JP2002346367A - Vacuum apparatus, method for controlling degree of vacuum in the apparatus, and program for controlling degree of vacuum - Google Patents

Abstract

PROBLEM TO BE SOLVED: To early detect an abnormality such as the generation of an abnormal outgas or the intrusion of a gas into a vacuum container from the outside on account of poor seal during evacuation to efficiently find out the cause for the abnormality, to predict the time necessary to reach the target degree of vacuum, and to optimize the baking time for attaining the target degree of vacuum within a short time. SOLUTION: The vacuum degree controller 2 of a vacuum apparatus 1 is provided with a means for predicting a theoretical pressure, a means 7 for calculating the quantity of an abnormal gas, a means 8 for judging an abnormality, a means 9 for calculating a pressure calibration value, a means 10 for predicting the time necessary to attain the target degree of vacuum, and a means 11 for display. The means 8 concretely judges an evacuation abnormality in each stage of evacuation, while the means 10 predicts the time necessary to reach the target degree of vacuum.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum device, a method of controlling the degree of vacuum, and a program for controlling a degree of vacuum.
The present invention relates to a vacuum device using a vacuum control device capable of detecting an abnormality in exhaust and predicting a time required to reach a target vacuum in a control relating to the vacuum of the vacuum device, a vacuum control method thereof, and a vacuum control program.

[0002]

2. Description of the Related Art A vacuum apparatus for a semiconductor manufacturing apparatus first comprises:
By being evacuated by an auxiliary pump such as a Roots blower and subsequently evacuated by a main pump such as a cryopump or a turbo molecular pump, for example, 1 × 10 ⁻⁶ (P
a) A high vacuum state of the order is reached. In other words, a vacuum device exhausts gas molecules in a vacuum vessel by adsorbing them on a cooled cryosurface or by flipping them off with the blades of a turbo-molecular pump. It takes 10 to 10 hours. In addition, the vacuum device is provided with an electric degassing member (baking heater) that generates heat to promote degassing of the inner wall surface of the vacuum vessel.

The above-mentioned vacuum apparatus for a semiconductor manufacturing apparatus generally means a vacuum apparatus used for a semiconductor manufacturing apparatus such as a sputtering apparatus, a dry etching apparatus, an E-gun apparatus, and a CVD apparatus. In addition, the vacuum apparatus, the vacuum degree control method thereof, and the vacuum degree control program of the present invention are not limited to the vacuum apparatuses used in these apparatuses.

Conventionally, a vacuum device for realizing a high vacuum state has
Although it is possible to know the final pressure inside the vacuum vessel and the final energizing current to the electric degassing member, it is possible to grasp the transition of the vacuum state inside the vacuum vessel from the start of evacuation to the end of evacuation. Did not.

That is, even if there are factors that cannot achieve a high vacuum state, such as dirt inside the vacuum vessel or failure of a sealing portion such as a vacuum valve, the vacuum device accurately determines these abnormalities during the evacuation. Because it was not possible, the main pump was operated for several hours to several tens hours until the scheduled evacuation end time. Further, the conventional vacuum apparatus cannot obtain effective information when taking measures against a factor that cannot achieve a high vacuum state, and has spent a great deal of effort in investigating the cause of exhaust abnormality.

In recent years, as a technique for improving this problem,
Japanese Patent Application Laid-Open No. 5-184904 discloses a technique of "a method for reducing the pressure of a vacuum apparatus for a semiconductor manufacturing apparatus and a vacuum apparatus for a semiconductor manufacturing apparatus". This technique will be described with reference to the drawings.

(Conventional Example) FIG. 8 is a schematic configuration diagram of a vacuum degassing apparatus for a semiconductor manufacturing apparatus in a conventional example.
FIG. 9 is a schematic enlarged view of a display screen of a display device used in a conventional vacuum degassing device for a semiconductor manufacturing apparatus.

In FIG. 1, the vacuum degassing device main body 1
01 denotes a vacuum vessel 102, a valve 105, a main pump 103, and a valve 1 connected in series with the vacuum vessel 102.
06, an auxiliary pump 104, an electrically heated degassing target member 107 and a pressure sensor 114 disposed inside the vacuum vessel 102, a degassing power supply device 108, a control device 109, and a display device 111. It is.

Here, the control device 109 has a built-in ammeter for measuring the amount of current supplied to the member 107 to be degassed, and a pressure sensor 114 for detecting the pressure inside the vacuum vessel of the vacuum vessel 102. It is connected. Thus, when the inside of the vacuum vessel 102 is evacuated, the vacuum degassing apparatus main body 101 is energized to the degassing member 107 that promotes the change of the pressure in the vacuum vessel 102 with time and the degassing of the vacuum vessel 102. The current change over time is recorded. Therefore, when any trouble occurs in the vacuum state of the vacuum container 102, an operator or the like based on the temporal change of the pressure in the vacuum container 102 and the temporal change of the amount of current supplied to the degassed member 107 based on this change. Pursue the cause of the failure.

[0010] In the vacuum degassing apparatus main body 101 thus configured, first, the vacuum container 102 is evacuated by the auxiliary pump 104, and then the main pump 103 is evacuated. Then, in the vacuum degassing apparatus main body 101, when the pressure in the vacuum vessel 102 becomes lower than a preset pressure, the control device 109 supplies a degassing current to the degassing target 107.

Here, a display device 111 for displaying a temporal change of the pressure in the vacuum vessel 102 and a temporal change of the amount of current supplied to the degassing member 107 is provided as shown in FIG. The change curve 112 of the vacuum pressure in the inside and the increase curve 113 of the degassing current are displayed. Therefore, when any trouble occurs in the vacuum state of the vacuum container 102, the worker or the like generates a trouble based on the change curve 112 of the vacuum pressure and the increase curve 113 of the degassing current recorded on the display device 111. The cause can be pursued.

Next, when the pressure in the vacuum chamber 102 reaches the set value and the degassing current reaches the set value, the main body 103 of the vacuum degassing apparatus stops the main pump 103 and sets the vacuum pump. The process shifts to a semiconductor manufacturing process using the container 102.

[0013]

However, the vacuum degassing apparatus main body 101 only stores a change curve 112 of the vacuum pressure and an increase curve 113 of the degassing current.
When an abnormality occurs in the vacuum state of the vacuum vessel 102, an operator or the like pursues the cause of the failure based on these records.
In Japanese Patent Application Publication No. 4 (1999) -1995, there is no description about a method of judging an abnormal state and a method of judging a cause of a defect from the change curve 112 of the vacuum pressure and the increase curve 113 of the degassing current. In other words, the vacuum degassing apparatus main body 101 early detects abnormalities such as the occurrence of abnormal degassing of the vacuum vessel 102 and the intrusion of gas from outside the vacuum vessel 102 due to defective sealing during the evacuation of the vacuum vessel 102. And the cause of the abnormality cannot be efficiently investigated.

Further, since the vacuum degassing apparatus main body 101 does not have a function of determining whether or not the target vacuum degree is reached, the vacuum degassing apparatus 101 sets the target vacuum degree suitable for the semiconductor manufacturing process during the evacuation of the vacuum vessel 10. There was a problem that it was not possible to determine whether to reach or not to reach.

Further, since the vacuum degassing apparatus main body 101 does not have a function of predicting the time until the set pressure is reached from the vacuum pressure change curve 112 and the degassing current increase curve 113, the vacuum vessel 102 is evacuated. During this process, there is a problem that it is impossible to predict a time until the pressure reaches a set pressure suitable for the semiconductor manufacturing process.

Further, in the conventional vacuum apparatus and vacuum degree control method, the relationship between the baking time by the electric degassing member and the degree of vacuum is not sufficiently considered, and therefore, the target vacuum degree is required to be reached in a short time. There is a problem that the baking time cannot be optimized.

The present invention has been made in order to solve the above-mentioned problems, and it is possible to prevent abnormal occurrence of abnormal degassing or intrusion of gas from the outside of a vacuum vessel due to poor sealing during vacuum evacuation of a vacuum apparatus. To efficiently investigate the cause of the exhaust abnormality, predict the time to reach the target vacuum degree, and optimize the baking time to reach the target vacuum degree in a short time It is an object of the present invention to provide a vacuum device capable of performing the above, a vacuum degree control method thereof, and a vacuum degree control program.

[0018]

In order to achieve this object, a vacuum apparatus according to the present invention comprises a vacuum container, a vacuum control device for controlling the degree of vacuum of the vacuum container, and a vacuum for exhausting gas in the vacuum container. A pump, a baking heater for heating a wall in the vacuum vessel, a pressure measuring means for measuring a pressure in the vacuum vessel, a wall temperature measuring means for measuring a wall temperature in the vacuum vessel, and a gas temperature in the vacuum vessel A vacuum device comprising gas temperature measuring means for measuring the pressure, wherein the vacuum degree control device, the theoretical pressure prediction means for predicting the theoretical pressure in the vacuum vessel after a unit time has elapsed from an arbitrary time, the unit from the arbitrary time An abnormal gas for calculating an abnormal gas amount from a difference between a measured pressure in the vacuum vessel measured by the pressure measuring means after a lapse of time and a theoretical pressure in the vacuum vessel predicted by the theoretical pressure predicting means. And quantity calculating means is a configuration in which and a abnormality determination means for determining an abnormality of said abnormal gas amount.

Thus, the abnormal gas amount is calculated from the difference between the measured pressure in the vacuum vessel measured by the pressure measuring means after a unit time has elapsed from an arbitrary time and the theoretical pressure in the vacuum vessel predicted by the theoretical pressure predicting means. Therefore, the abnormality of the abnormal gas amount can be accurately determined.

Further, in the vacuum apparatus according to the present invention, the theoretical pressure predicting means may be configured such that the amount of gas released from the wall surface inside the vacuum vessel at the arbitrary time, the pressure inside the vacuum vessel measured by the pressure measuring means, The theoretical pressure in the vacuum vessel after a unit time has elapsed from the arbitrary time is predicted based on the volume of the vessel, the pumping speed of the vacuum pump, and the pumping limit pressure of the vacuum pump. In this way, the theoretical pressure in the vacuum vessel can be accurately predicted.

In the vacuum apparatus according to the present invention, the abnormal gas amount may be a sum of a degas amount from a wall surface in the vacuum vessel per unit time and an intrusion gas amount from outside the vacuum vessel. is there. In this way, the cause of the abnormality can be limited with respect to the abnormality of the abnormal gas amount.

In the vacuum apparatus according to the present invention, the abnormality judging means judges the abnormality of the degassing amount and / or the intruding gas amount based on the abnormal gas amount.
In this way, it is possible to detect whether the abnormal gas amount is abnormal, whether the amount of degassing gas is abnormal, the amount of intruding gas, or whether the amount of degassing gas is abnormal. And the cause of the abnormality can be specifically identified.

Further, in the vacuum apparatus according to the present invention, the abnormality determining means may be configured such that the value of the abnormal gas amount is set to a predetermined abnormality determination value in a time interval from the start of baking until the abnormal gas amount hardly changes. When it becomes smaller, the degassing amount is determined to be abnormal. In this manner, particularly in the evacuation stage after the start of baking, for example, when baking is not performed due to a failure of a baking heater or when baking is insufficient, vaporization is performed at a high temperature such as oil. A substance that is easy to be vaporized is not sufficiently vaporized, and an abnormality relating to the amount of degassing can be detected. Further, since the cause of the exhaust abnormality can be specified as baking failure, the cause can be easily investigated.

Further, in the vacuum apparatus according to the present invention, the abnormal gas judging means may be provided in a time interval after the start of baking and after the amount of the abnormal gas hardly changes until the end of the baking. When the value of the amount is larger than a predetermined abnormality determination value of the abnormal gas amount, it is determined that the degassing amount and / or the intrusion gas amount is abnormal.

In this way, after the baking is started, and during the time interval from the time when the abnormal gas amount hardly changes to the time when the baking is completed, for example, the degassing amount from the wall surface in the vacuum vessel, An abnormality in the amount of gas entering from outside the vacuum vessel can be detected, and the cause of the abnormality in the exhaust can be easily investigated. Further, in the time interval from the start of baking until the abnormal gas amount hardly changes, the value of the abnormal gas amount becomes larger than the abnormality determination value set in advance, and it is determined that the degas amount is not abnormal. When the value of the abnormal gas amount becomes larger than the preset abnormal gas amount abnormality determination value in the time interval from the time when the abnormal gas amount hardly changes until the end of baking, the cause of the exhaust abnormality is usually determined. Since it can be identified as a vacuum-system seal failure, the cause can be easily investigated.

Further, the vacuum apparatus of the present invention is characterized in that, when the abnormality determining means increases the abnormal gas amount without converging to a substantially constant value in a time interval from the end of baking to reaching the target vacuum degree, It is configured to determine that the amount of intruding gas is abnormal. In this way, during the time interval from the end of baking to the target vacuum degree,
For example, it is possible to detect the amount of invading gas based on a bad seal of the vacuum system, and it is possible to easily investigate the cause of the exhaust abnormality.

In the vacuum apparatus according to the present invention, the abnormality determining means determines an abnormality in the degassing amount and / or the intruding gas amount based on the accumulated value of the abnormal gas amount. In this manner, based on the accumulated value of the abnormal gas amount, it is accurately determined whether the abnormality is the degas amount, the intrusion gas amount, or the abnormality of the degas amount and the intrusion gas amount. It can be detected, and the cause of the abnormality can be specified specifically.

Further, in the vacuum apparatus according to the present invention, the abnormality determining means determines that the degassing amount and / or the intruding gas amount is abnormal if the accumulated value of the abnormal gas amount does not decrease after the completion of the baking. There is. In this way, after the baking is completed, for example, since the baking heater is not normally turned off, the amount of degas due to the gas in the vacuum container not being re-adsorbed to the wall surface, or the intrusion from outside the vacuum container due to a minute leak An abnormality in the gas amount can be detected, and the cause of the exhaust abnormality can be easily investigated.

Further, in the vacuum apparatus of the present invention, the vacuum pump is a cryopump and the theoretical pressure is as follows:
formula

(Equation 3) t: time P (t): theoretical pressure in the vacuum vessel at time t P ₀ : pressure at time t = 0 (pressure in the vacuum vessel measured by pressure measuring means at an arbitrary time) P _eq0 : pressure on the cryopump of the cryopump pressure, constant determined from the gas temperature and the cryo-surface temperature (= vacuum pumping limit coefficient determined by the gas type and pump) S _c: pumping speed factor of the cryopump (= constant) V: the vacuum container volume C _v: vacuum The value obtained from the surface area of the inner wall of the vessel, the thermal velocity of gas molecules, the adsorption time of gas molecules on the inner wall of the vacuum vessel, the probability of gas molecules adhering to the inner wall of the vacuum vessel, and the surface roughness coefficient of the inner wall of the vacuum vessel (= The gas pressure coefficient, the gas temperature, and the gas release coefficient that varies depending on the vacuum vessel. The internal pressure of the chamber is substituted into P ₀ as the initial pressure in the vacuum vessel, and the theoretical pressure P (t) in the vacuum vessel after t hours is calculated. In this case, when the vacuum pump is a cryopump, the theoretical pressure after the elapse of a unit time in the theoretical pressure prediction means can be accurately predicted.

Further, the vacuum apparatus according to the present invention is characterized in that the amount of abnormal gas at the time of the elapse of the unit time after the elapse of a predetermined time from the start of the baking until the end of the baking from the time of the elapse of the unit time. , Calculated as a pressure correction value per unit time, and from the baking end time to the time when the target vacuum degree is reached, the abnormal gas amount calculated per unit time from the baking end time calculated and stored in advance and stored. A pressure correction value calculating means for calculating a value obtained by dividing by the abnormal gas amount at the baking end time and multiplying the abnormal gas amount at the time of each unit time elapse as a pressure correction value per unit time; and The amount of gas released from the inner surface of the vacuum vessel, the pumping speed of the vacuum pump, and the limiting pressure of the vacuum pump at each time A time for each elapse of the unit time based on a degas amount from the inner wall surface of the vacuum vessel, a volume of the vacuum vessel, and a pressure correction value calculated for each unit time calculated by the pressure correction value calculation means. The predicted pressure after a lapse of a unit time is predicted using the pressure in the vacuum vessel as an initial pressure in the above, and the predicted pressure after the next unit time is predicted using the predicted pressure as an initial pressure. Calculates the time at which the predicted pressure reaches the target vacuum degree, and predicts the time from the time at which the unit time elapses to the time at which the target vacuum degree is reached as the target vacuum degree arrival time. It is configured to have arrival time prediction means.

In this way, the target vacuum arrival time can be accurately predicted on the basis of the pressure correction value calculated by the pressure correction value calculation means.

Further, in the vacuum apparatus of the present invention, the vacuum pump is a cryopump, and a predicted pressure after a lapse of a unit time is expressed by the following equation (2).

(Equation 4) t: time P (t): predicted pressure at time t P ₀ : pressure at time t = 0 (pressure in the vacuum vessel measured by pressure measuring means at an arbitrary time) P _eq0 : pressure and gas on the cryopump surface of the cryopump Constant obtained from temperature and cryosurface temperature (= vacuum pump evacuation limit coefficient determined by gas type and pump) S _c : Evacuation speed of cryo pump (= constant) V: Vacuum container volume C _v : Vacuum container inner wall surface Surface area, thermal motion velocity of gas molecules, adsorption time of gas molecules on the inner wall of vacuum vessel, adhesion probability of gas molecules on the inner wall of vacuum vessel, value obtained from surface roughness coefficient of inner wall of vacuum vessel (= coefficient of gas, temperature of the gas, the gas discharge coefficient varies by vacuum container) P _{x (t):} calculated in a pressure correction value obtained by said pressure correction value calculating means, the target degree of vacuum arrival time predicting means , There once before predicted pressure P in the iterative calculation of (t) as a configuration substituted into P _0, to calculate the predicted pressure P after t time (t).

Thus, when the vacuum pump is a cryopump, it is possible to accurately predict the predicted pressure after the elapse of the unit time in the target vacuum degree reaching time predicting means.

Further, in the vacuum apparatus of the present invention, the target vacuum degree reaching time predicting means changes the baking end time and predicts the target vacuum degree reaching time with respect to the changed baking end time. The baking end time with the shortest target vacuum degree arrival time is selected as the optimum baking end time. This way,
The baking end time can be simulated so that the target degree of vacuum is reached in the shortest time.

Further, the method for controlling the degree of vacuum of a vacuum apparatus according to the present invention comprises a vacuum vessel, a vacuum degree control device for controlling the degree of vacuum of the vacuum vessel, a vacuum pump for exhausting gas in the vacuum vessel, A baking heater for heating a wall of the vacuum vessel, a pressure measuring means for measuring a pressure in the vacuum vessel, a wall temperature measuring means for measuring a wall temperature in the vacuum vessel,
And a method of controlling the degree of vacuum of a vacuum device comprising gas temperature measuring means for measuring a gas temperature in the vacuum vessel, wherein the theoretical pressure predicting means of the vacuum degree control device is a vacuum vessel after a unit time elapses from an arbitrary time. Predict the internal theoretical pressure, the abnormal gas amount calculating means of the vacuum degree control device, the measured pressure in the vacuum vessel measured by the pressure measuring means after a unit time has elapsed from the arbitrary time and the theoretical pressure predicting means predicted by the theoretical pressure predicting means Calculate the abnormal gas amount from the difference with the theoretical pressure in the vacuum vessel,
An abnormality determining means of the vacuum control device determines the abnormality of the abnormal gas amount.

As described above, the present invention is also effective as a method of controlling the degree of vacuum in a vacuum apparatus. According to this control method, an exhaust abnormality is detected based on the abnormal gas amount obtained from the abnormal gas amount calculating means. be able to.

Further, in the method of controlling the degree of vacuum of a vacuum apparatus according to the present invention, the pressure correction value calculating means of the vacuum degree control device may calculate a time from a time every unit time after a predetermined time has elapsed since the start of baking. Until the baking end time, the abnormal gas amount at the time of each unit time elapse is calculated as a pressure correction value per unit time, and is calculated and stored in advance from the baking end time to the time of reaching the target vacuum degree. The abnormal gas amount calculated for each unit time from the baking end time is divided by the abnormal gas amount at the baking end time, and a value obtained by multiplying the abnormal gas amount at the unit time elapse time by a unit time Calculated as a pressure correction value for each unit, the target degree of vacuum arrival time prediction means of the vacuum degree control device, Gas discharge amount of the vacuum vessel wall,
The pumping speed of the vacuum pump, the pumping limit pressure of the vacuum pump, the degassing amount from the inner wall surface of the vacuum vessel, the volume of the vacuum vessel, and the unit time calculated by the pressure correction value calculating means. Based on the pressure correction value, predicting the predicted pressure after the elapse of a unit time as the initial pressure with the pressure in the vacuum vessel at the time of the elapse of the unit time, further, the predicted pressure as the initial pressure,
Repeat the calculation to predict the predicted pressure after the next unit time,
The time at which the predicted pressure predicted by the repeated calculation reaches the target vacuum degree is calculated, and the time from the time at which the unit time elapses to the time at which the target vacuum degree is reached is predicted as the target vacuum degree arrival time. There is a way. In this way, the target vacuum arrival time prediction means can predict the target vacuum arrival time.

The vacuum control program for a vacuum device according to the present invention comprises a vacuum container, a vacuum control device for controlling the degree of vacuum of the vacuum container, a vacuum pump for exhausting gas in the vacuum container, Baking heater for heating the wall of the vessel, pressure measuring means for measuring the pressure in the vacuum vessel,
A vacuum degree control program for a vacuum apparatus comprising a wall surface temperature measuring means for measuring a wall temperature in the vacuum vessel, and a gas temperature measuring means for measuring a gas temperature in the vacuum vessel, wherein a unit time elapses from an arbitrary time. The procedure for predicting the theoretical pressure in the vacuum chamber after, and the measured pressure in the vacuum vessel measured by the pressure measuring means after the unit time elapses from the arbitrary time and the theoretical pressure in the vacuum vessel predicted by the theoretical pressure prediction means It is configured to execute a procedure of calculating an abnormal gas amount from the difference and a procedure of determining an abnormality of the abnormal gas amount.

As described above, the present invention is also effective as a vacuum degree control program for a vacuum apparatus. According to this control program, an exhaust abnormality is detected based on the abnormal gas amount obtained from the abnormal gas amount calculating means. be able to.

Further, the vacuum degree control program of the vacuum apparatus of the present invention is characterized in that, after a lapse of a predetermined time from the start of baking, from the time every unit time has elapsed until the baking end time, the time every unit time has elapsed. Is calculated as a pressure correction value per unit time, and
From the baking end time to the time when the target vacuum degree is reached, the abnormal gas amount calculated per unit time from the previously calculated and stored baking end time is divided by the abnormal gas amount at the baking end time, and
A procedure of calculating a value obtained by multiplying the abnormal gas amount at the time of each unit time as a pressure correction value for each unit time, and the gas release amount of the vacuum vessel inner wall surface at the time of the unit time, The pumping speed of the vacuum pump, the pumping limit pressure of the vacuum pump, the degassing amount from the inner wall surface of the vacuum vessel, the volume of the vacuum vessel, and the pressure calculated per unit time calculated by the pressure correction value calculating means. Based on the correction value, predicting a predicted pressure after a lapse of a unit time by using the pressure in the vacuum vessel at the time of each lapse of the unit time as an initial pressure, and further using the predicted pressure as an initial pressure, and It repeats the calculation for predicting the predicted pressure of, calculates the time when the predicted pressure predicted by the repeated calculation reaches the target vacuum degree, and The time from time to time to reach the target degree of vacuum, it is constituted to execute a step of predicting a desired vacuum degree arrival time. This way,
The target vacuum arrival time can be predicted.

Further, the vacuum apparatus of the present invention comprises a vacuum vessel, a vacuum control device for controlling the degree of vacuum in the vacuum vessel, a vacuum pump for exhausting gas in the vacuum vessel, and heating the wall surface in the vacuum vessel. A vacuum comprising a baking heater, pressure measuring means for measuring the pressure in the vacuum vessel, wall temperature measuring means for measuring the wall temperature in the vacuum vessel, and gas temperature measuring means for measuring the gas temperature in the vacuum vessel. An apparatus, wherein the vacuum degree control program for a vacuum apparatus according to claim 16 or 17 is installed. As described above, the vacuum apparatus of the present invention can detect an exhaust abnormality based on an abnormal gas amount by using a vacuum apparatus equipped with a vacuum degree control program.
In addition, it is possible to predict the target vacuum arrival time.

[0042]

Embodiments of the present invention will be described below with reference to the drawings. First, an embodiment of a vacuum device of the present invention will be described with reference to the drawings.

[Vacuum Apparatus] FIG. 1 is a schematic block diagram for explaining a basic configuration of an embodiment of a vacuum apparatus according to the present invention. In FIG. 1, a vacuum device 1 includes a vacuum container 1a, a vacuum control device 2 for controlling the degree of vacuum of the vacuum container 1a, a vacuum pump 12 for evacuating gas in the vacuum container 1a, and heating the wall surface in the vacuum container 1a. Baking heater 13, pressure measuring means 3 for measuring the pressure in vacuum vessel 1a, wall temperature measuring means 4 for measuring the wall temperature in vacuum vessel 1a, and gas temperature measurement for measuring the gas temperature in vacuum vessel 1a. The configuration includes the means 5.

Here, the vacuum vessel 1a is a vessel for achieving a high vacuum state for performing a vacuum process in a semiconductor device manufacturing process or the like, and the inside of the vacuum vessel 1a has an adverse effect on evacuation. In order to remove the applied oil and the like, it has been sufficiently washed with a dedicated washing liquid or the like.

The vacuum pump 12 is a vacuum pump such as a cryopump or a diffusion pump for discharging gas in the vacuum vessel 1a to the outside of the vacuum vessel 1a. Although not shown, a vacuum pipe, a vacuum valve, a vacuum It is connected to the vacuum vessel 1a via a fitting or the like, and exhausts gas inside the vacuum vessel 1a.

The baking heater 13 is disposed on the inner wall surface of the vacuum vessel 1a, heats (bakes) the inner wall face of the vacuum vessel 1a, volatilizes volatile substances attached to the inner wall face at an early stage, and evacuates. To assist. Further, the baking heater 13 is not limited to a heater provided on the inner wall surface of the vacuum vessel 1a.
a) A heater (not shown) is provided around an input material such as a semiconductor element to be input into the device (a) to volatilize volatile substances attached to the surface of the input material at an early stage and assist in evacuation. Shall be considered.

The pressure measuring means 3 is a pressure gauge such as a Mcland gauge or a spinning rotor gauge, and is disposed in the vacuum vessel 1a for measuring the pressure in the vacuum vessel 1a.

The wall surface temperature measuring means 4 and the gas temperature measuring means 5 are thermometers such as a thermocouple and a platinum thermal resistor, and are used for measuring the wall surface temperature in the vacuum vessel 1a.
It is arranged on the wall in a. The gas temperature measuring means 5
Is not provided, the gas temperature can be estimated from the inner wall surface temperature of the vacuum vessel 1a measured by the wall surface temperature measuring means 4. Further, the pressure measuring means 3, the wall surface temperature measuring means 4 and the gas temperature measuring means 5 are provided for the vacuum vessel 1a.
It is attached with a vacuum joint, etc.
a has a configuration capable of maintaining a high vacuum state.

The vacuum control device 2 in the vacuum device 1
It comprises theoretical pressure predicting means 6, abnormal gas amount calculating means 7, abnormal determining means 8, pressure correction value calculating means 9, target vacuum arrival time predicting means 10, and display means 11.

The theoretical pressure predicting means 6 predicts the theoretical pressure in the vacuum vessel after a lapse of a unit time from an arbitrary time. That is,
The theoretical pressure predicting unit 6 is electrically connected to the pressure measuring unit 3, the wall surface temperature measuring unit 4, and the gas temperature measuring unit 5, and inputs the pressure inside the vacuum container, the wall surface temperature, and the gas temperature in the vacuum container 1a. . The theoretical pressure predicting means 6 calculates the amount of gas released from the wall surface inside the vacuum vessel 1a at any time, the pressure inside the vacuum vessel measured by the pressure measuring means 3, the volume of the vacuum vessel 1a, the pumping speed of the vacuum pump 12, and Based on the exhaust pressure limit of the vacuum pump 12, predict (calculate) the theoretical pressure in the vacuum vessel after a lapse of a unit time from an arbitrary time.
I do.

Thus, the theoretical pressure predicting means 6
Can accurately predict the theoretical pressure in a vacuum vessel. Further, the theoretical pressure prediction means 6 outputs the calculation result to the abnormal gas amount calculation means 7 and the display means 11. In addition,
The theoretical pressure estimating means 6 is not limited to the evacuation method of the vacuum pump 12, and can predict the theoretical pressure without trouble even for vacuum pumps having different evacuation methods such as a cryopump and a diffusion pump. .

Here, the amount of gas released from the wall surface in the vacuum vessel 1a at an arbitrary time is determined by the thermal motion velocity of the gas molecules in the vacuum vessel 1a obtained from the gas temperature and the gas molecular weight measured by the gas temperature measuring means 5, Wall temperature measuring means 4
Container 1 determined from the wall temperature measured by
It can be obtained from the adsorption time of gas molecules on the inner wall surface a, the surface area of the inner wall surface of the vacuum vessel 1a, the probability of gas molecules adhering in the vacuum vessel 1a, and the surface roughness coefficient of the inner wall surface of the vacuum vessel 1a.

In this specification, the term “unit time” refers to a time preset in the vacuum controller 2. That is, it usually takes several hours to several tens of hours to evacuate the vacuum container 1a to a high vacuum state. Therefore, if the unit time is set to, for example, one second, the time interval is too short. When the time is set, the time interval is too long, so that a few minutes is generally set as the unit time. In addition, it is needless to say that the unit time can be set at any interval.

The amount of gas released from the wall surface in the vacuum vessel 1a is expressed by the following equation (3).

(Equation 5) C _V : Amount of gas released from the inner wall surface of the vacuum vessel v: Average velocity of thermal motion of gas molecules τ: Adsorption time of gas molecules on the inner wall surface of the vacuum vessel T: Surface temperature in the vacuum vessel A: Surface area in the vacuum vessel δ: Vacuum Adhesion probability of gas molecules on the inner wall surface of the container β: It is obtained by the surface roughness coefficient of the inner wall surface of the vacuum container. Here, the theoretical pressure predicting means 6 includes (3)
It is preferable to calculate the gas release amount using the equation. In this case, the gas release amount on the wall surface inside the vacuum vessel 1a can be calculated with high accuracy.

Further, the most probable speed is adopted as the above-mentioned thermal momentum speed, and this thermal momentum speed (most probable speed) is expressed by the following equation (4).

(Equation 6) M ': Gas molecular weight Tg: Gas temperature Here, the theoretical pressure predicting means 6 satisfies (4)
It is preferable to calculate the thermal momentum velocity by using the equation. In this case, the thermal momentum velocity can be calculated with high accuracy.

The adsorption time of gas molecules on the inner wall surface of the vacuum vessel is expressed by the following equation (5).

(Equation 7) τ: adsorption time of gas molecules on the inner wall surface of the vacuum vessel τ ₀ : gas residence time constant E: activation energy of gas desorption R: gas constant T: surface temperature in the vacuum vessel Here, the theoretical pressure predicting means 6 satisfies (5)
It is preferable to calculate the adsorption time by using the equation. In this case, the adsorption time of the gas molecules on the inner wall surface of the vacuum vessel 1a can be calculated with high accuracy.

The theoretical pressure predicting means 6 is provided for the vacuum vessel 1
The gas in a is assumed to be the vapor of the substance most contained in the gas, and the gas molecular weight of the substance may be used as the gas molecular weight. In this case, the gas in the vacuum chamber 1a is Even when the vapor of a plurality of substances is used as a main component, the thermal motion velocity of gas molecules can be calculated with high accuracy.

Therefore, when the gas in the vacuum vessel 1a is mainly composed of water vapor, the theoretical pressure predicting means 6 assumes that the gas in the vacuum vessel 1a is water vapor and uses the gas molecular weight of water as the gas molecular weight. In this case, the thermal motion velocity of the gas molecule can be calculated with high accuracy.

The theoretical pressure predicting means 6 is provided for the vacuum vessel 1.
When the gas in a is mainly composed of oil vapor, the vacuum vessel 1
The gas in a may be assumed to be oil vapor, and the gas molecular weight of the vacuum oil may be used as the gas molecular weight. In this case, the thermal motion velocity of the gas molecules can be calculated with high accuracy.

The abnormal gas amount calculating means 7 includes the pressure measuring means 3
And a theoretical pressure in the vacuum vessel after a unit time has elapsed from the arbitrary time, and a pressure in the vacuum vessel measured by the pressure measuring means 3 after a unit time has elapsed from the arbitrary time. Enter Further, the abnormal gas amount calculating means 7 calculates a difference between the measured vacuum vessel pressure and the vacuum vessel theoretical pressure, and calculates an abnormal gas quantity based on the pressure difference. The abnormal gas amount calculation means 7 is electrically connected to the abnormality determination means 8, the pressure correction value calculation means 9 and the display means 11, and is connected to the abnormality determination means 8, the pressure correction value calculation means 9 and the display means 11. The abnormal gas amount is output.

As described above, in the vacuum apparatus 1, the abnormal gas amount calculating means 7 calculates the difference between the measured pressure in the vacuum vessel measured by the pressure measuring means and the theoretical pressure in the vacuum vessel predicted by the theoretical pressure predicting means 6. Since the abnormal gas amount is calculated, the abnormality determining means 8 can accurately determine the abnormality of the abnormal gas amount.

Further, the vacuum apparatus 1 calculates the abnormal gas amount
The amount of degassing from the wall surface inside the vacuum vessel 1a per unit time and the amount of gas entering from the outside of the vacuum vessel 1a may be configured to be a sum. Can be limited to degassing and / or invading gas.

In the vacuum apparatus 1, the abnormality judging means 8
On the basis of the abnormal gas amount calculated by the abnormal gas amount calculating means 7, the abnormality of the degassing amount and / or the intrusion gas amount is determined, and the determination result is output to the display means 11. This way,
It is possible to detect whether the abnormal gas amount is abnormal, whether the amount of degassing amount is abnormal, the amount of intruding gas amount, or the abnormal amount of degassing amount and the amount of intruding gas amount.
The cause of the abnormality can be specifically identified. Note that the abnormality determination means 8 compares the profile with the profile of the abnormal gas amount when vacuuming is performed in a normal state, for example.
It is possible to determine whether or not the exhaust is abnormal.

In the vacuum apparatus 1, the abnormality determining means 8
It is preferable to determine the abnormality of the degassing amount and / or the intrusion gas amount based on the accumulated value of the abnormal gas amount. In this case, the abnormality of the degassing amount is determined based on the accumulated value of the abnormal gas amount. It is possible to accurately detect whether there is an abnormality, an abnormality in the amount of intruding gas, or an abnormality in the amount of degassing and the amount of intruding gas, and specifically identify the cause of the abnormality.

In other words, the abnormality determination means 8 is not limited to the case where the determination is made based on the abnormal gas amount calculated for each unit time, but the cumulative value of the abnormal gas amount calculated by the abnormal gas amount calculation means 7 May exceed the preset value, it may be determined that the exhaust is abnormal. In such a case, based on the cumulative value of the abnormal gas amount, the exhaust abnormality in the high vacuum state or a state close to the high vacuum state may be determined. Can be determined with higher accuracy.

In this specification, “abnormality of the outgassing amount and / or the amount of the intruding gas” means “abnormality of the outgassing amount, the abnormality of the intruding gas amount, or the abnormality of the outgassing amount and the intrusion gas amount”. These abnormalities are collectively referred to as exhaust abnormality.

The abnormality determining means 8 determines that the degassing amount is abnormal when the value of the abnormal gas amount becomes smaller than a predetermined abnormality determination value in the time interval from the start of baking until the abnormal gas amount hardly changes. In this case, particularly when the baking is not performed due to a failure of the baking heater or the baking is insufficient at the evacuation stage after the start of the baking, the oil content is reduced. For example, a substance that easily vaporizes at a high temperature, such as a high temperature, is not sufficiently vaporized, and an abnormality relating to the degassing amount can be detected. Further, since the cause of the exhaust abnormality can be specified as baking failure, the cause can be easily investigated.

If a substance which is easily vaporized at a high temperature, such as oil, is not sufficiently vaporized during this time interval, a high vacuum state cannot be reached or the arrival time becomes long even if the evacuation is continued. , And the exhaust becomes abnormal.

Further, after the baking has been started, the abnormality determining means 8 determines the value of the abnormal gas amount in a time interval from when the abnormal gas amount hardly changes to the end of the baking. When the gas amount is larger than the abnormality determination value, it is preferable to determine that the amount of degassing and / or the amount of intruding gas is abnormal.
After the start of baking, in the time interval from the time when the amount of abnormal gas hardly changes to the end of baking, for example, the amount of degassing from the wall surface in the vacuum vessel or the intrusion gas from the outside of the vacuum vessel An abnormality in the amount can be detected, and the cause of the exhaust abnormality can be easily investigated.

The abnormality determination means 8 may be configured to determine that the amount of degassing and / or the amount of invading gas is abnormal if the cumulative value of the amount of abnormal gas does not decrease after baking.
In this way, after the baking is completed, for example, since the baking heater is not normally turned off, the amount of degassing due to the gas in the vacuum vessel not being re-adsorbed to the wall surface, or intrusion from outside the vacuum vessel due to a minute leak An abnormality in the gas amount can be detected, and the cause of the exhaust abnormality can be easily investigated.

Further, the abnormality determination means 8 determines whether the abnormality has occurred in the time interval from the end of baking to the time when the target vacuum degree is reached.
When the abnormal gas amount does not converge to a substantially constant value and increases, it is preferable to determine that the amount of the intruding gas is abnormal. In this case, for example, in the time interval from the end of baking to reaching the target vacuum degree, for example, the vacuum system It is possible to detect the amount of invading gas based on the defective seal, and to easily investigate the cause of the exhaust abnormality.

In the period from the start of baking until the abnormal gas amount hardly changes, the vacuum vessel 1
As the temperature in the area a rises, the oil and the like adhering to the inside of the vacuum vessel 1a evaporate vigorously, so that the amount of the abnormal gas usually becomes a variable value without being stabilized.

Next, each calculation formula when the vacuum pump 12 is a cryopump will be described. First, when the vacuum pump 12 is a cryopump, the theoretical pressure in the vacuum vessel after a lapse of a unit time from an arbitrary time is calculated by the above equation (1).

(Equation 8) t: time P (t): theoretical pressure in the vacuum vessel at time t P ₀ : pressure at time t = 0 (pressure in the vacuum vessel measured by pressure measuring means at an arbitrary time) P _eq0 : cryopump of the cryopump pressure, constant determined from the gas temperature and the cryo-surface temperature (= the gas type and the vacuum pumping limit coefficient determined by the pump) S _c: pumping speed of the cryopump (= constant) V: the vacuum container volume C _v: vacuum container Surface area, thermal velocity of gas molecules, adsorption time of gas molecules on the inner wall of the vacuum vessel, adhesion probability of gas molecules on the inner wall of the vacuum vessel, value obtained from the surface roughness coefficient of the inner wall of the vacuum vessel (= gas coefficient) , Gas temperature, and gas release coefficient depending on the vacuum vessel). Here, the theoretical pressure predicting means 6 substitutes the pressure in the vacuum vessel from the pressure measuring means 3 at an arbitrary time into P ₀ as the initial vacuum vessel pressure, and calculates the theoretical pressure P (t) in the vacuum vessel after t hours. The calculation is preferably performed. In this case, when the vacuum pump is a cryopump, the theoretical pressure in the vacuum vessel can be accurately predicted.

The theoretical pressure predicting means 6 adopts the equation (1), and when estimating the theoretical pressure in the vacuum vessel in consideration of the gas release coefficient C _v , the degree of vacuum in the vacuum vessel 1a increases. Alternatively, when the baking heater 13 is turned on, the degassing greatly affects the theoretical pressure in the vacuum vessel 1a. Therefore, in the equation (1), the gas pressure is set so that the calculated theoretical pressure and the actually measured pressure become substantially the same. Emission coefficient C _v
May be modified and set.

When calculating the equation (1), the pumping speed of the cryopump is calculated by the following equation (6).

(Equation 9) Sc: Pumping speed of the cryopump C: Crowsing coefficient between the exhaust port of the vacuum pump and the low-temperature surface A: Area of the cryogenic surface of the vacuum pump c (Tg): Condensation probability on the cryogenic surface of the vacuum pump v (Tg): Gas molecule It is determined by the average thermal motion velocity of. Here, the theoretical pressure predicting means 6 includes (6)
The pumping speed of the cryopump may be calculated using the equation. In this case, the theoretical pressure predicting means 6 can calculate the pumping speed of the cryopump with high accuracy.

When calculating the equation (1), the cryopump exhaust limit pressure is calculated by the following equation (7).

(Equation 10) P _eq0 : Cryo pump exhaust limit pressure P _eq : Cryo surface pressure Ts: Cryo surface temperature Tg: Gas temperature Here, the theoretical pressure predicting means 6 calculates (7)
It is preferable to calculate the cryopump exhaust limit pressure using the equation. In this case, the theoretical pressure predicting means 6 can accurately calculate the cryopump exhaust limit pressure.

Next, the above equation (1) will be proved from the basic equation of the pumping speed of the cryopump. The basic formula for the pump speed S (m ³ / sec) of the cryopump
(m ² ), the Crowsing coefficient between the pump outlet and the cold surface is C, the probability of condensation is the temperature function c (T) of the incident molecule coming to the cold surface, and the average value of the thermal motion velocity v (T) of the gas molecule. , The temperature of the gas molecules Tg (K), the temperature of the cryogenic surface Ts (K), the pressure P (Pa), and the pressure of the cryogenic surface P _eq (Pa), the following expression (8) is obtained.

[Equation 11]

Here, the temperature of the gas and the temperature of the cryosurface are kept constant, and the following equation (9) is obtained.

(Equation 12) And the following equation (10)

(Equation 13) In other words, the above equation (8) is simplified to the following equation (11).

[Equation 14]

Further, the degassing amount from the wall surface of the vacuum vessel 1a includes a pressure P (Pa), an average value v (m / sec) of thermal velocities of molecules,
Adsorption time τ (sec), the probability adhesion molecules δ (0 <δ <1) , when the surface roughness coefficient β (> 1), the suction gas density ^{σ (Pa · m 3 · m} -2) of the container surface ^{[ 2 ]} is represented by the following equation (12).

(Equation 15)

Assuming that the surface area A (m ² ) and the pressure change ΔP (Pa) in the vacuum vessel 1 a are expressed by the following equation (12),
3) It is expressed by the equation.

(Equation 16)

The equation (8) in which the exhaust performance of the vacuum vessel 1a and the cryopump and the amount of degassing from the wall are added, the pressure in the vacuum vessel is P (t) (Pa), the volume is V (m ³ ), The surface area A (m ² ) in the vacuum vessel and the gas density on the solid surface are represented by σ (Pa · m
³・ m ⁻² ), Cryopump pumping speed S (m ³ / sec)
Where, the gas amount PV in the vacuum vessel at time t + Δt after the elapse of Δt time from t is the gas quantity PV in the vacuum vessel at time t.
If it is considered that this is equal to the sum of the change in the gas release amount Aσ of the solid portion from t to t + Δt time and the amount of gas exhausted by the cryopump in the Δt time, the following equation (14) can be expressed.

[Equation 17] Here, AΔPvτδβ / 4 is the amount of degassing from the wall surface at the time Δt, and ΔP is the pressure change amount P (t +
Δt) -P (t).

When the above equation (14) is rearranged into a differential equation, it is expressed by the following equation (15).

(Equation 18)

When the differential equation of the above equation (15) is solved, the equation for predicting the theoretical pressure inside the vacuum vessel 1a using the cryopump is given by the above equation (1).

[Equation 19] Becomes Here, Cv is given by the following equation (3).

(Equation 20) And P _eq0 is the following equation (7)

(Equation 21) There is.

In the above formulas (1), (3) and (7), V: volume (m ³ ) of the vacuum vessel 1a P _eq : pressure on the cryo surface (P _a ) Tg: gas temperature (K ) Ts: cryo surface temperature (K) S _c: pumping speed of the cryopump (m ³ / sec) a: surface area of the vacuum vessel (m ²⁾ v: average value of the thermal velocity of gas molecules (m / sec) τ: adsorption time (sec) of gas molecules on the wall δ: adhesion probability of gas molecules β: surface roughness coefficient

[0085] In addition, the theoretical pressure prediction means 6, the P ₀ of equation (1) for predicting the vacuum vessel theoretical pressure in said vacuum container 1a, in the vacuum container 1a as measured by the pressure measuring means 3 By substituting the pressure in the vacuum container and calculating by adding a unit time to t, the theoretical pressure in the vacuum container after the unit time can be predicted.

In the vacuum device 1, when the vacuum vessel 1a is evacuated by the vacuum pump 12 and reaches a vacuum region on the order of about 10 ^-3 (Pa), the degree of vacuum is controlled by degassing from the inner wall surface. becomes the area, the gas discharge coefficient C _v from the wall surface, it is necessary to appropriately set. Therefore, (3)
In the formula, the surface roughness coefficient β of the inner wall surface of the vacuum vessel is preferably set to a value of 1 or more.
The gas release coefficient _Cv can be largely corrected so that the theoretical pressure calculated in the equation (1) and the actually measured pressure become substantially the same.

Further, the vacuum apparatus 1 may be configured so that the probability of gas molecules colliding with the inner wall surface of the vacuum vessel 1 and being adsorbed on the wall surface is represented by a value from 0 to 1 as a gas molecule adhesion probability. In this way, the probability of gas molecule adhesion can be set to a value of practical accuracy.

The vacuum apparatus 1 may be configured such that the wall temperature inside the wall of the vacuum vessel 1a is assumed to be the gas temperature in the vacuum vessel 1a. In addition, since it is not necessary to form a mounting hole which may cause a sealing failure in the vacuum vessel 1a, the danger of the sealing failure can be reduced by that much.

Next, the pressure correction value calculating means and the target degree of vacuum reaching time estimating means of the vacuum apparatus 1 will be described. The vacuum apparatus 1 preferably includes a pressure correction value calculation unit 9 and a target vacuum degree arrival time prediction unit 10. In this case, the target vacuum is calculated based on the pressure correction value calculated by the pressure correction value calculation unit 9. The attainment time estimating means 10 can accurately calculate the target evacuation time.

Here, the pressure correction value calculating means 9 is electrically connected to the abnormal gas amount calculating means 7 and detects abnormalities at a time every unit time after a lapse of a predetermined time from the start of baking. Assuming that the gas amount does not change until the baking end time, the abnormal gas amount at the time of the unit time elapse from the time of each unit time elapse to the baking end time is a pressure correction value for each unit time. Is calculated as The predetermined time from the start of baking may be set to the time from the start of baking until the abnormal gas amount hardly changes. In such a case, the predetermined time is affected by the initial fluctuation of the degassing amount after the start of baking. The pressure correction value can be obtained with high accuracy without any need.

The pressure correction value calculating means 9 calculates the abnormal gas amount calculated per unit time from the baking end time calculated and stored in advance from the baking end time to the time when the target degree of vacuum is reached. A value obtained by dividing by the abnormal gas amount at the baking end time and further multiplying the abnormal gas amount at the time of each unit time elapse,
The pressure correction value is calculated as a pressure correction value for each unit time, and this pressure correction value is output to the target vacuum arrival time prediction means 10.

The target vacuum degree arrival time predicting means 10 includes pressure measuring means 3, wall temperature measuring means 4, gas temperature measuring means 5,
And is electrically connected to the pressure correction value calculating means 9 for inputting the pressure inside the vacuum vessel, the wall temperature, the gas temperature and the pressure correction value.

The target vacuum degree arrival time predicting means 10
Is the vacuum vessel 1 at each time the unit time has passed.
a The amount of gas released from the wall surface, the evacuation speed of the vacuum pump 12, the evacuation limit pressure of the vacuum pump 12, the amount of degassing from the inner wall surface of the vacuum vessel 1, the volume of the vacuum vessel 1, and the pressure correction value calculation means 9. Based on the pressure correction value that changes every unit time, the pressure inside the vacuum vessel 1a at the time of each elapse of the unit time is predicted as the initial pressure, and the predicted pressure after the elapse of the unit time is predicted. As, the calculation for predicting the predicted pressure after the next unit time is repeated, the time at which the predicted pressure predicted by the repetitive calculation reaches the target vacuum degree is calculated, and the time at each unit time elapse is set to the target vacuum degree. The time until the arrival time is predicted as the target vacuum degree arrival time, and the arrival time and / or the time until the arrival time is output to the display unit 11.

The amount of gas released from the wall surface of the vacuum vessel 1a at each time when the unit time has elapsed is determined by the pressure inside the vacuum vessel measured by the pressure measuring means 3, the gas temperature measured by the gas temperature measuring means 5 at the same time. Thermal velocity of gas molecules in vacuum vessel 1a determined from gas molecular weight, adsorption time of gas molecules on inner wall surface of vacuum vessel 1a, surface area of inner wall surface of vacuum vessel 1a, probability of adhesion of gas molecules in vacuum vessel 1a, vacuum vessel 1a is determined from the surface roughness coefficient of the inner wall surface.

When the vacuum pump 12 is a cryopump, the predicted pressure after a lapse of a unit time is calculated by the above equation (2).

(Equation 22) t: time P (t): predicted pressure at time t P ₀ : pressure at time t = 0 (pressure in the vacuum vessel measured by pressure measuring means at an arbitrary time) P _eq0 : pressure and gas on the cryopump surface of the cryopump constant determined from the temperature and cryo surface temperature (= the gas type and the vacuum pumping limit coefficient determined by the pump) S _c: pumping speed of the cryopump (= constant) V: the vacuum vessel volume C _v: in the vacuum chamber wall Value obtained from surface area, thermal velocity of gas molecules, adsorption time of gas molecules on the inner wall of vacuum vessel, adhesion probability of gas molecules on the inner wall of vacuum vessel, surface roughness coefficient of inner wall of vacuum vessel (= coefficient of gas, P _x (t): The pressure correction value obtained by the pressure correction value calculation means. Here, target vacuum arrival time prediction means 1
0 is the predicted pressure P (t) immediately before in the repetitive calculation as P ₀
To calculate the predicted pressure P (t) after time t. In this case, when the vacuum pump 12 is a cryopump, the target pressure elapse time estimating means 10 after the unit time elapses Can be accurately calculated.

Further, the vacuum apparatus 1 determines the pressure inside the vacuum vessel measured by the pressure measuring means 3, the theoretical pressure inside the vacuum vessel after the elapse of a unit time predicted by the theoretical pressure predicting means 6, and the determination result determined by the abnormality determining means 8. Display means 1 such as a CRT for displaying the predicted pressure predicted by the target vacuum arrival time prediction means 10 and the target vacuum arrival time.
It is good to have a configuration provided with 1.
Since the vacuum state in the vacuum vessel 1a can be easily grasped, the operability can be improved.

The vacuum control device 2 of the vacuum device 1
The theoretical pressure predicting means 6, the abnormal gas amount calculating means 7, the abnormal determining means 8, the pressure correction value calculating means 9 and the target vacuum arrival time predicting means 10 do not need to be individually provided. It is a matter of course that a single computer having a (CPU) and a memory may be used, and the computer may execute each process of the above-described units by a control program described later. In other words, each process of each of the above means is executed by the vacuum control device 2 in which the control program and the computer cooperate.

Next, the operation of the vacuum apparatus 1 having the above configuration will be described. First, the vacuum vessel 1a is evacuated by a roughing vacuum pump (not shown), then evacuated by a vacuum pump 12 such as a cryopump, and the inner wall surface is heated (baked) by a baking heater 13. . Here, the pressure in the vacuum chamber 1a is firstly reduced by being evacuated by the roughing vacuum pump, and then increased once by the heating of the baking heater 13,
Subsequently, the air is evacuated by the vacuum pump 12 and gradually lowers.

The theoretical pressure predicting means 6 is provided by means of the pressure inside the vacuum vessel 1a measured by the pressure measuring means 3 per unit time, the wall temperature measured by the wall temperature measuring means 4, and the gas temperature measuring means 5 When the measured gas temperature is inputted, for example, when the vacuum pump 12 is a cryopump, the inside of the vacuum vessel after a unit time is calculated using the above-mentioned equation (1) which is a formula for calculating the theoretical pressure inside the vacuum vessel of the cryopump. Predict the theoretical pressure.

Subsequently, the abnormal gas amount calculating means 7 calculates the theoretical pressure in the vacuum vessel after the elapse of the unit time calculated by the theoretical pressure estimating means 6 and the pressure in the vacuum vessel from the pressure measuring means 3 after the elapse of the unit time. The value obtained by subtracting the theoretical pressure in the vacuum vessel after the elapse of the unit time calculated by the theoretical pressure estimating means 6 from the pressure in the vacuum vessel after the elapse of the unit time of the pressure measuring means 3 is calculated as the abnormal gas amount (the degassing amount and (Sum of the amount of invading gas).

Next, in the vacuum apparatus 1, the abnormality determining means 8
An abnormality is determined using the abnormal gas amount calculated by the abnormal gas amount calculating means 7. Here, when the abnormal gas amount calculating means 7 starts calculating the abnormal gas amount, the abnormality determining means 8 calculates the time from the start of baking to the target degree of vacuum by the abnormal gas amount calculating means 7 from the start of baking. A first time interval until the abnormal gas amount no longer changes, a second time interval from when the abnormal gas amount calculated by the abnormal gas amount calculating means 7 does not change to the end of baking, and a target from the end of the baking. The method is divided into a third time section until the degree of vacuum is reached, and in each time section, the abnormality determination method is switched to perform the abnormality determination.

First, an abnormality determination method in the first time section will be described with reference to the drawings. FIG. 2 is a schematic diagram for explaining an abnormality determination diagram in a first time section. In the figure, the horizontal axis is the time (sec) from the start of baking, and the vertical axis is the amount of abnormal gas calculated by the abnormal gas amount calculating means 7 (in the figure, the number of moles is displayed). And the transition of the number of moles (abnormal gas amount) in two cases during normal times and two cases during abnormal times. This transition of the number of moles is an example.

The conversion into the number of moles is performed by the abnormality determining means 8 by transforming the abnormal gas amount (obtained as a pressure value) obtained by the abnormal gas amount calculating means 7 into a gas equation PV = nRT. Equation (16) below

(Equation 23) Is done by substituting into In this way, the abnormal gas amount obtained as the pressure value can be converted to the number of moles, which is the gas amount, and abnormality determination can be performed using this number of moles.

In the first time section, that is, in the section from 0 sec to about 5000 sec in the figure, the abnormal gas quantity calculated by the abnormal gas quantity calculating means 7 decreases from the start of baking (0 sec) to about 1800 sec. , About 1800 sec. Here, about 1
The minimum value of the abnormal gas amount at 800 sec is usually a negative value when converted to the number of moles.

Then, the abnormality determination means 8 determines the abnormality in this time interval based on the minimum value of the negative value based on the minimum value of the negative value in the normal state when the target vacuum degree is reached in this time interval. If the value falls below a first normal / abnormal judgment value set in advance, it is judged as abnormal.

That is, the pressure measuring means 3 after the elapse of the unit time
The difference between the vacuum pressure measured in the vacuum vessel and the theoretical pressure in the vacuum vessel after the elapse of the unit time becomes a negative value because the vacuum measured by the pressure measuring means 3 from the theoretical pressure in the vacuum vessel after the elapse of the unit time This is because the pressure in the container has decreased, which means that the degassing amount at this time (after the elapse of the unit time) is small. Then, when the minimum value of the abnormal gas amount falls below the first normal / abnormal judgment value, the vacuum device 1
For example, when baking is not performed due to a failure of a baking heater, or when baking is insufficient, a substance that is easily vaporized at a high temperature, such as oil, is not sufficiently vaporized.

Therefore, in the vacuum apparatus 1, the abnormality judging means 8 judges that there is an abnormality relating to the degassing amount when the number of moles of the abnormal gas amount falls below the first normal abnormality judging value set in advance. , The abnormality can be detected at an early stage, and the cause of the exhaust abnormality can be identified as a baking defect, making it easy to investigate the cause and avoiding the trouble of trying to evacuate despite the abnormality. can do. Note that in FIG.
The vacuum apparatus 1 is operated until 0 sec. However, in actual work, when the number of moles of the abnormal gas amount falls below the first normal abnormality determination value, the vacuum apparatus 1 may be stopped to take measures against the cause. it can.

Next, an abnormality determination method in the second time section will be described with reference to the drawings. FIG. 3 is a schematic diagram for explaining an abnormality determination diagram in a second time section. In the figure, the horizontal axis is the time (sec) from the start of baking, and the vertical axis is the amount of abnormal gas calculated by the abnormal gas amount calculating means 7 (in the figure, the number of moles is displayed). And the transition of the number of moles (abnormal gas amount) in two cases during normal times and two cases during abnormal times. This transition of the number of moles is an example.

In the second time section, that is, in the section from about 5000 sec to about 25000 sec in the figure, the abnormal gas amount calculated by the abnormal gas amount calculating means 7 has a substantially constant value. The abnormal gas amount having a substantially constant value is usually a positive value.

Therefore, the abnormality determination means 8 sets the above-mentioned substantially constant value in advance as the abnormality determination in this time interval based on the substantially constant value in the normal state when the target vacuum degree is reached. If the value exceeds a given second normal / abnormality determination value, it is determined to be abnormal.

The difference between the pressure inside the vacuum vessel measured by the pressure measuring means 3 after the lapse of the unit time and the theoretical pressure inside the vacuum vessel after the lapse of the unit time becomes a positive value because the pressure after the lapse of the unit time This is because the pressure inside the vacuum vessel measured by the pressure measuring means 3 is larger than the theoretical pressure inside the vacuum vessel, which means that the amount of degassed and / or invaded gas is larger.
If the value of the abnormal gas amount that has become substantially constant exceeds the second normal / abnormal judgment value, the vacuum device 1 may, for example, remove the amount of degas from the wall surface in the vacuum vessel 1a or the vacuum vessel 1a. There is a large amount of gas entering from the outside.

Therefore, when the abnormality determining means 8 determines that the number of moles of the abnormal gas exceeds the second normal abnormality determination value set in advance, the vacuum apparatus 1 sets the degassing amount and / or
Or, since it is determined that there is an abnormality related to the amount of intruding gas, abnormality detection can be performed at an early stage.
Efforts to evacuate can be avoided. Although the vacuum device 1 is operated up to 30,000 seconds in FIG. 3, in actual work, when the number of moles of the abnormal gas amount exceeds the second normal abnormality determination value,
It is possible to stop the vacuum device 1 and take measures against the cause.

In the first time interval from the start of baking until the abnormal gas amount hardly changes, the minimum value of the abnormal gas amount becomes larger than the first normal abnormality judgment value set in advance, and the degassing amount becomes smaller. In the case where it is not determined that the abnormality is abnormal, in the second time interval from the time when the abnormal gas amount hardly changes until the end of baking, the value of the abnormal gas amount is the second normal abnormality determination value set in advance. When it becomes larger, normally, the cause of the exhaust abnormality can be specified as a vacuum system sealing defect (defective intrusion gas amount due to minute leak), so that the cause investigation can be easily performed.

In the first time interval, the minimum value of the abnormal gas amount becomes smaller than the first normal abnormality determination value set in advance, and it is determined that the degas amount is abnormal. If it is not determined to be abnormal, but the minimum value of the abnormal gas amount is small and close to the first normal abnormality determination value, in the second time interval, the gas present on the inner wall surface of the vacuum vessel 1a increases. Therefore, the cause of the exhaust abnormality may be specified as the abnormality of the degassing amount in some cases. When the value of the abnormal gas amount becomes larger than the second normal / abnormal judgment value, it is needless to say that there may be a case where the abnormal gas amount can be specified as a defect of the degassing amount and the intrusion gas amount.

Next, a method of determining abnormality in a third time section will be described with reference to the drawings. FIG. 4 is a schematic diagram illustrating a first abnormality determination diagram in a third time section. In the figure, the horizontal axis is the time (sec) from the start of baking, and the vertical axis is the amount of abnormal gas calculated by the abnormal gas amount calculating means 7 (in the figure, the number of moles is displayed). The transition of the accumulated mole number (accumulated abnormal gas amount) in one example in a normal state and one example in an abnormal state is shown. The transition of the cumulative mole number is an example.

In the third time section, that is, in the section from the time of baking OFF to the time of reaching the target degree of vacuum in the same figure, the cumulative abnormal gas amount (cumulative Number) decreases from the time of baking OFF. That is, when the baking is turned off, the temperature of the wall surface in the vacuum vessel 1a decreases, and the gas remaining in the vacuum vessel 1a is re-adsorbed on the wall face. Decreases from time to time.

On the other hand, if the cumulative number of moles does not decrease from the time of baking OFF, for example, baking is
In spite of the FF, the power supply to the baking heater 13 is not interrupted, the wall surface temperature in the vacuum container 1a does not decrease, and the gas remaining in the vacuum container 1a is not re-adsorbed to the wall surface. This is the case where a degassing abnormality has occurred, or a case where a vacuum-based sealing defect (defective intrusion gas amount due to minute leak) has occurred.

Therefore, the abnormality judging means 8 sets the third normal abnormality judgment criterion after the completion of baking (OFF).
If the cumulative value of the abnormal gas amount does not decrease, it is determined that the amount of degassing and / or the amount of intruding gas is abnormal. In this way, after the baking is completed, for example, it is possible to detect an abnormality in the amount of degassing based on the baking heater or an abnormality in the amount of gas entering from outside the vacuum vessel due to a minute leak, and to investigate the cause of the exhaust abnormality. It can be done easily.

In consideration of the fact that the reliability of the on / off control of the baking heater 13 is usually high, the abnormality determining means 8 determines that the cause of the exhaust abnormality in the second time interval is as follows.
In order to confirm whether or not this is due to a defect in the amount of intruding gas,
By turning off the baking heater 13 temporarily, it is possible to confirm that there is no abnormality in the amount of intruding gas due to a minute leak.

FIG. 5 is a schematic diagram for explaining a second abnormality determination diagram in a third time section.
In the figure, the horizontal axis represents time (se) from the start of baking.
c), and the vertical axis is the abnormal gas amount calculated by the abnormal gas amount calculating means 7 (in the figure, converted to the number of moles and displayed). Over time). This transition of the number of moles is an example.

In the third time section, that is, in the section from the time of baking OFF to the time of reaching the target degree of vacuum in the same figure, the abnormal gas amount (molar number) calculated by the abnormal gas amount calculating means 7 in a normal state. Is baking OF
It decreases from the time of F, then increases and becomes a substantially constant value.
That is, when the baking is turned off and the gas remaining in the vacuum vessel 1a is re-adsorbed to the wall surface,
The amount of abnormal gas (number of moles) becomes a substantially constant value.

On the other hand, the amount of abnormal gas (number of moles) decreased from the time of baking OFF, increased thereafter, and further increased.
The case where the value increases without being substantially constant is a case where a vacuum seal failure (defective intrusion gas amount due to a minute leak) has occurred.

Therefore, as a fourth normal abnormality determination criterion, the abnormality determining means 8 determines whether the amount of the invading gas increases when the amount of abnormal gas increases rather than becoming substantially constant during the time interval from baking OFF to reaching the target vacuum degree. It is determined that the amount is abnormal. In this way, for example, during the time interval from baking OFF to reaching the target degree of vacuum, it is possible to detect, for example, the amount of invasive gas based on a vacuum system sealing defect, and to easily investigate the cause of the exhaust abnormality. it can.

Next, the pressure correction value calculating means 9 assumes that the abnormal gas amount at the time of each unit time elapse after a predetermined time has elapsed from the start of baking does not change until the baking end time. From the time at which the unit time elapses to the baking end time, the abnormal gas amount at the time at which the unit time elapses is calculated as a pressure correction value per unit time.

The pressure correction value calculating means 9 calculates the abnormal gas amount calculated per unit time from the baking end time calculated and stored in advance from the baking end time to the time when the target degree of vacuum is reached. A value obtained by dividing by the abnormal gas amount at the baking end time and further multiplying the abnormal gas amount at the time of each unit time elapse,
It is calculated as a pressure correction value for each unit time.

Next, the target vacuum degree arrival time prediction means 10
Is the vacuum vessel 1 at each time the unit time has passed.
a The amount of gas released from the inner wall surface, the pumping speed of the vacuum pump 12, the limit pressure of the vacuum pump 12, the amount of degassing from the inner wall surface of the vacuum vessel 1a, the volume of the vacuum vessel 1a, and the pressure correction value calculation means 9 Based on the pressure correction value calculated for each unit time, a predicted pressure after a lapse of a unit time is predicted using the pressure in the vacuum vessel 1a at each time of the unit time as an initial pressure, and the predicted pressure With the initial pressure as the initial pressure, the calculation for predicting the predicted pressure after the next unit time is repeated, the time at which the predicted pressure predicted by the repetitive calculation reaches the target vacuum degree is calculated, and the target time is calculated from the time for each elapse of the unit time. The time to reach the degree of vacuum is predicted as the target time to reach the degree of vacuum, and the time to reach and / or the time to reach the time is output to the display means 11. .

Further, the target vacuum degree arrival time prediction means 10
Automatically changes the baking end time, predicts the target vacuum degree reaching time with respect to the changed baking end time, and determines the shortest baking end time with the target vacuum degree reaching time as the optimal baking end time. It is preferable that the time is selected as the time. In this case, the baking end time can be simulated so that the target degree of vacuum is reached in the shortest time.

Further, the target vacuum arrival time prediction means 10
Can also calculate the predicted pressure at the scheduled evacuation end time. In this way, if evacuation is continued in the middle of evacuation, the degree of vacuum at the evacuation end time is estimated. Can be predicted from the predicted pressure.

The display means 11 displays, for example, the pressure inside the vacuum vessel measured by the pressure measuring means 3, the theoretical pressure inside the vacuum vessel after a unit time calculated by the theoretical pressure predicting means 6, and the abnormal gas amount calculating means. 7 is a graph showing the abnormal gas amount calculated by 7, the determination result determined by the abnormality determining means 8, the optimal baking end time, the predicted pressure, and the target vacuum degree reaching time calculated by the target vacuum degree reaching time predicting means 10. Display with numerical values, characters, etc.

As described above, the vacuum device of the present invention
During vacuum evacuation of the vacuum vessel, abnormalities such as the occurrence of abnormal degassing or intrusion of gas from outside the vacuum vessel due to poor sealing are detected, and the cause of the abnormality is efficiently investigated.
It is possible to predict the time required to reach the target degree of vacuum, and to optimize the baking time to reach the target degree of vacuum in a short time. If the vacuum pump 12 is a cryopump, the target vacuum arrival time may be calculated using the equation (2). In this case, the target vacuum arrival time can be calculated with high accuracy.

The vacuum apparatus 1 is not limited to the above configuration. For example, although an error occurs in the theoretical pressure predicting means 6, the wall temperature in the vacuum vessel 1a and the gas temperature in the vacuum vessel 1a are controlled. It is possible to predict the theoretical pressure in the vacuum vessel after a unit time by not measuring but keeping a constant value. In the target vacuum degree reaching time prediction means 10, although an error occurs, the wall temperature in the vacuum vessel 1a and the gas temperature in the vacuum vessel 1a are not measured.
With a fixed value, a predicted pressure after a lapse of a unit time can be calculated.

Further, even if the theoretical pressure predicting means 6 uses a pump other than a cryopump as the vacuum pump 12, the vacuum apparatus 1 uses the cryogenic pressure calculation formula for calculating the theoretical pressure in the vacuum vessel after a unit time has elapsed. By replacing the pump term with the term of the vacuum pump to be used, it is possible to predict the theoretical pressure inside the vacuum vessel after a unit time has elapsed for any vacuum pump. Similarly, even when the target vacuum degree reaching time prediction means 10 uses a pump other than a cryopump as the vacuum pump 12, the target cryopump term of the theoretical pressure calculation formula in the vacuum vessel after the elapse of the unit time is obtained. By substituting the term of the vacuum pump to be used, it is possible to calculate a predicted pressure after a unit time for any vacuum pump.

[Vacuum Degree Control Method of Vacuum Apparatus] The present invention is also effective as a vacuum degree control method of a vacuum apparatus.
A method of controlling the degree of vacuum for operating the vacuum device having the above configuration will be described with reference to the drawings. FIG. 6 is a schematic time chart for explaining the method of controlling the degree of vacuum of the vacuum apparatus according to the present invention. FIG. 7 is a schematic flowchart for explaining the method of controlling the degree of vacuum of the vacuum apparatus according to the present invention.

In FIG. 6, first, the power of the vacuum control device 2 is turned on, and subsequently, data input is performed. Here, the input data includes data such as the volume of the vacuum vessel 1a, data such as the type and performance of the vacuum pump 12, baking start time and end time, target degree of vacuum, scheduled evacuation end time, and first normal time. An abnormality determination value, a second normal abnormality determination value, an abnormal gas amount at a previously calculated baking end time, an abnormal gas amount calculated per unit time from the baking end time, and the like.

[0135] Next, the vacuum pump 12 is turned ON, the start evacuation of the vacuum vessel 1a is followed at any time T _0, the theoretical pressure prediction means 6 and the abnormal gas amount calculating means 7
Starts calculating the amount of abnormal gas and continues to calculate the amount of abnormal gas every unit time.

Here, in the method of continuously calculating the abnormal gas amount every time the unit time elapses, as shown in FIG. 7, the vacuum control device 2 starts the process at the unit time n-1 (step S1). . Then, the theoretical pressure predicting means 6 acquires the pressure value P (n-1) from the pressure measuring means 3 (step S2), and subsequently obtains the wall temperature T from the wall temperature measuring means 4.
h (n-1) is obtained (step S3), and further, the gas temperature Tg (n-1) is obtained from the gas temperature measuring means 5 (step S4). Next, the theoretical pressure prediction means 6
The predicted pressure P '(n) for the unit time n is calculated and further stored in the memory (step S5).

Next, when the unit time elapses from the unit time n-1 and reaches the unit time n, the vacuum control device 2 starts the processing in the unit time n (step S11).
Then, the theoretical pressure predicting unit 6 acquires the pressure value P (n) from the pressure measuring unit 3 (step S12), and subsequently acquires the wall surface temperature Th (n) from the wall surface temperature measuring unit 4 (step S13). Further, a gas temperature Tg (n) is obtained from the gas temperature measuring means 5 (step S14). Next, the theoretical pressure predicting means 6 calculates a predicted pressure P '(n + 1) for the unit time n + 1, and further stores it in the memory (step S15). Subsequently, the abnormal gas amount calculating means 7
Calculates an abnormal gas amount P _x (n) from the predicted pressure P ′ (n) and the pressure value P (n) (step S16).

Next, in the vacuum control device 2, the pressure correction value calculating means 9 sends the abnormal gas amount _Px
(N) is input to calculate a pressure correction value (step S1).
7). Here, the method of calculating the pressure correction value differs depending on the section of evacuation. Subsequently, the predicted pressure after the unit time n + 1 is predicted by the target degree of vacuum arrival time prediction means 10 (step S18). And the display means 11
The predicted pressure is displayed as a result (step S20).

Further, the abnormality determining means 8 receives the abnormal gas amount Px (n) from the abnormal gas amount calculating means 7 and calculates the abnormal gas amount Px (n) by the above-described abnormality determining method in the first, second and third time intervals. An abnormality is determined (step S19). Then, the display unit 11 displays the result of the abnormality determination (step S20).

Next, when the unit time elapses from the unit time n and reaches the unit time n + 1, the vacuum control device 2 starts processing in the unit time n + 1 (step S2).
1). Then, the theoretical pressure predicting means 6 includes the pressure measuring means 3
Pressure value P (n + 1) is obtained from (step S22),
Subsequently, the wall surface temperature Th (n +
1) is obtained (step S23), and the gas temperature Tg (n + 1) is obtained from the gas temperature measuring means 5 (step S24). Next, the theoretical pressure predicting means 6 calculates a predicted pressure P ′ (n + 2) for the unit time n + 2,
The data is stored in the memory (step S25). Subsequently, the abnormal gas amount calculating means 7 calculates the predicted pressure P ′ (n + 1) and the pressure value P
The abnormal gas amount P _x (n + 1) is calculated from (n + 1) (step S26).

Next, in the vacuum control device 2, the pressure correction value calculating means 9 sends the abnormal gas amount P _x
(N + 1) is input, and a pressure correction value is calculated (step S27). Here, the method of calculating the pressure correction value differs depending on the section of evacuation. Subsequently, the predicted pressure after the unit time n + 2 is predicted by the target degree of vacuum arrival time prediction means 10 (step S28). And display means 11
Displays the predicted pressure as a result (step S30).

Further, the abnormality determining means 8 receives the abnormal gas amount P _x (n + 1) from the abnormal gas amount calculating means 7 and performs the above-described abnormality determining method in the first, second and third time sections. Is determined (Step S2
9). Then, the display means 11 displays the result of the abnormality determination (step S30). In this manner, the vacuum control device 2 continues to calculate the abnormal gas amount every unit time (unit time n−1 → unit time n → unit time n + 1 →...).

Next, a method of determining an abnormal gas amount by the abnormality determining means 8 will be described with reference to FIG. As described above, the abnormality determination unit 8 performs the abnormality determination using the abnormal gas amount calculated by the abnormal gas amount calculation unit 7.

Here, when the abnormal gas amount calculating means 7 starts calculating the abnormal gas amount, the abnormal judging means 8 operates from the start of baking until the abnormal gas amount calculated by the abnormal gas amount calculating means 7 does not change. A first time interval, a second time interval from the time when the abnormal gas amount calculated by the abnormal gas amount calculating means 7 does not change to the end of baking,
It is divided into a third time interval from the end of baking to reaching the target vacuum degree, and in each time interval, a first normal abnormality judgment value, a second normal abnormality judgment value, a third normal Abnormality is determined based on the normal / abnormality determination standard.

[0145] The pressure correction value calculating means 9, even after baking start, from time T _n which abnormal gas quantity calculated is not substantially changed by the abnormal gas amount calculating means 7 calculates the pressure correction value .

Here, the pressure correction value calculating means 9 is a
Unit time after a predetermined time has passed since the start of
Time of every passing (T_{n + 3}Abnormal gas volume (Q)
_{n + 3}) Does not change until the baking end time
Assuming, that is, a certain amount of time has elapsed since baking started
Some time later (T_n) To the time per unit time
(T _{n + 3}Abnormal gas volume (Q)_{n + 3}) But above
The time (T _{n + 3}) To finish baking
Assuming that it does not change until the
Time of every passing (T_{n + 3}) To baking end time
Is the time (T_{n + 3}In)
Abnormal gas volume (Q_{n + 3}) Is the pressure compensation value per unit time
Is calculated as

In the figure, for example, when one unit time has elapsed from the present time, the time for each elapse of the unit time is T _{n + 4} (not shown), and the time for each elapse of the unit time (T _{n + 4} ) From the time t to the baking end time, the abnormal gas amount (Q _{n + 4} ) at the time (T _{n + 4} ) every unit time has been calculated as a pressure correction value per unit time.

From the baking end time to the time when the target degree of vacuum is reached, the pressure correction value calculating means 9 calculates the abnormal gas amount (Q) calculated per unit time from the previously calculated and stored baking end time. _m1 ,
Q _m2 , Q _m3 ...) is divided by the abnormal gas amount (Q _m0 ) at the baking end time, and further multiplied by the abnormal gas amount Q _{n + 3} at the time T _{n + 3} for each unit time, that is, Q _{n + 3} × ( _Qm1 / _Qm0 ), Q
_{n + 3} × (Q _m2 / Q _m0 ), Q _{n + 3} × (Q _m3 / Q
_m0 ) are calculated as pressure correction values per unit time.
That is, the pressure correction value is previously calculated and stored, any unit time baking end time is proportional to the abnormal gas amount Q _m at the time Tm has elapsed.

Next, the target vacuum arrival time prediction means 10
Are the amount of gas released from the inner wall surface of the vacuum vessel 1a, the exhaust speed of the vacuum pump 12, the limit pressure of exhaustion of the vacuum pump 12, and the amount of degassing from the inner wall surface of the vacuum vessel 1a at the time ( _{Tn + 3} ) every unit time. , The volume of the vacuum container 1a, and the pressure correction value calculated for each unit time calculated by the pressure correction value calculation means 9, the pressure in the vacuum container at the time (T _{n + 3} ) at each unit time has elapsed. The predicted pressure after the elapse of the unit time is predicted as the initial pressure, and further, the calculation for predicting the predicted pressure after the next unit time is repeated using the calculated predicted pressure as the initial pressure, and the predicted pressure calculated by the repeated calculation is the target pressure. The time to reach the degree of vacuum is calculated, and the time from the time (T _{n + 3} ) at each unit time elapse to the time to reach the target vacuum degree is predicted as the target vacuum degree time I do.

As described above, according to the method for controlling the degree of vacuum in the vacuum vessel, during the evacuation of the vacuum vessel, abnormalities such as occurrence of abnormal degassing or intrusion of gas from outside the vacuum vessel due to poor sealing are detected. In addition, the cause of the abnormality can be efficiently investigated, the time required to reach the target vacuum degree can be predicted, and the baking time for reaching the target vacuum degree in a short time can be optimized.

[Vacuum Degree Control Program for Vacuum Apparatus] The present invention is also effective as a vacuum degree control program for a vacuum apparatus. Is executed.
In other words, the vacuum degree control program predicts the theoretical pressure in the vacuum vessel, calculates an abnormal gas amount, performs an abnormality determination process for determining an exhaust abnormality, calculates a pressure correction value, and predicts a target vacuum degree arrival time. Target vacuum degree reaching time prediction processing can be performed.

That is, the abnormality determination processing and the target vacuum degree arrival time prediction processing are executed by the vacuum apparatus 1 in which the control program and the vacuum degree controller 2 cooperate. In particular,
The degree of vacuum control program includes a procedure for causing the theoretical pressure predicting means 6 to predict the theoretical pressure in the vacuum vessel, a procedure for causing the abnormal gas amount calculating means 7 to calculate an abnormal gas amount, and a procedure for causing the abnormal determining means 8 to determine exhaust abnormality. A procedure for causing the pressure correction value calculating means 9 to predict the pressure correction value, a procedure for causing the target vacuum degree reaching time predicting means 10 to predict the target vacuum degree reaching time,
And a procedure for causing the display means 11 to display information on the vacuum state in the vacuum vessel 1a.

As described above, the vacuum degree control program of the vacuum apparatus detects abnormalities such as occurrence of abnormal degassing or intrusion of gas from the outside of the vacuum container due to poor sealing during the evacuation of the vacuum container, In addition to efficiently examining the cause, the time required to reach the target vacuum degree can be predicted, and the baking time for reaching the target vacuum degree in a short time can be optimized.

The vacuum control program can be stored not only in the ROM of the computer but also in a computer-readable recording medium such as an external storage device and a portable recording medium. Here, the external storage device refers to a storage expansion device that incorporates a recording medium such as a magnetic disk and is externally connected to the information processing device 11. On the other hand, a portable recording medium is a recording medium that can be mounted on a recording medium drive (drive device) and that is portable, such as a CD-ROM, a flexible disk, a memory card, and a magneto-optical disk. .

Then, the program stored in the recording medium is loaded into the RAM of the computer and executed by the CPU. By this execution, each function of the above-described vacuum control device 2 is realized. When a control program is loaded by a computer, the control program held by another computer can be downloaded to its own RAM or external storage device using a communication line.

Further, the vacuum apparatus of the present invention comprises a vacuum vessel, a vacuum control device for controlling the degree of vacuum in the vacuum vessel, a vacuum pump for exhausting gas in the vacuum vessel, and a baking heater for heating the wall surface in the vacuum vessel. A pressure measuring means for measuring a pressure in the vacuum vessel, a wall temperature measuring means for measuring a wall temperature in the vacuum vessel, and a gas temperature measuring means for measuring a gas temperature in the vacuum vessel, comprising: A vacuum device control program for the vacuum device according to claim 16 or 17 may be installed. In this way, by using a vacuum device having the vacuum control program installed, the vacuum device can be configured based on an abnormal gas amount. In addition, it is possible to detect an exhaust abnormality, and to predict a target vacuum degree reaching time.

In the vacuum apparatus according to the present invention, the abnormality determining means determines the exhaustion abnormality based on the accumulated value of the abnormal gas amount. Vacuum control device that determines by different abnormality determination methods, vacuum control device using a vacuum pump as a cryopump, vacuum control device that calculates target vacuum arrival time using pressure correction value, selected as optimal baking end time The degree of vacuum control devices can be implemented independently of each other, and can also be implemented as a combination of these, and it goes without saying that the respective effects can be exhibited. Although the present invention has been described as a vacuum device, the present invention can, of course, exert the same effects as a vacuum degree control method for a vacuum device and a vacuum degree control program for a vacuum device.

[0158]

As described above, according to the vacuum apparatus, the method of controlling the degree of vacuum, and the program for controlling the degree of vacuum according to the present invention, during the evacuation of the vacuum vessel, the vacuum caused by abnormal degassing of the vacuum vessel or defective sealing is caused. An abnormality such as gas intrusion from the outside of the container can be determined, and an abnormality such as occurrence of abnormal degassing or gas intrusion can be detected, and the cause of the abnormality can be efficiently investigated. Further, according to the vacuum apparatus, its degree of vacuum control method and the degree of vacuum control program, the time required to reach the target degree of vacuum is predicted, and the baking time for reaching the target degree of vacuum in a short time is optimized. Can be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram for explaining a basic configuration of an embodiment of a vacuum apparatus according to the present invention.

FIG. 2 is a schematic diagram for explaining an abnormality determination diagram in a first time section.

FIG. 3 is a schematic diagram for explaining an abnormality determination diagram in a second time section.

FIG. 4 is a schematic diagram for explaining a first abnormality determination diagram in a third time section.

FIG. 5 is a schematic diagram for explaining a second abnormality determination diagram in a third time section.

FIG. 6 is a schematic time chart for explaining a method of controlling the degree of vacuum of the vacuum apparatus according to the present invention.

FIG. 7 is a schematic flowchart for explaining a method of controlling the degree of vacuum of the vacuum apparatus according to the present invention.

FIG. 8 is a schematic configuration diagram of a vacuum degassing apparatus for a semiconductor manufacturing apparatus in a conventional example.

FIG. 9 is a schematic enlarged view of a display screen of a display device used in a vacuum degassing device for a semiconductor manufacturing apparatus in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum container 1a Vacuum container 2 Controller 3 Pressure measuring means 4 Wall temperature measuring means 5 Gas temperature measuring means 6 Theoretical pressure predicting means 7 Abnormal gas amount calculating means 8 Abnormality judging means 9 Pressure correction value calculating means 10 Target vacuum arrival time Predicting means 11 Display means 12 Vacuum pump 13 Baking heater 101 Vacuum degassing device main body 102 Vacuum vessel 103 Main pump 104 Auxiliary pump 105 Valve 106 Valve 107 Degassing member 108 Degassing power supply 109 Control device 111 Display device 112 Vacuum pressure Change curve 113 Degassing current increase curve 114 Pressure sensor

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/3065 H01L 21/31 A 21/31 21/302 BF Term (Reference) 4K029 DA02 EA03 FA00 4K030 DA06 EA11 JA09 5F004 AA16 BC02 CA02 CA07 5F045 BB08 EG03 EG05

Claims (18)

[Claims] 1. A vacuum container, a vacuum control device for controlling the degree of vacuum of the vacuum container, a vacuum pump for exhausting gas in the vacuum container, a baking heater for heating a wall surface in the vacuum container, A vacuum measuring device for measuring the pressure of the vacuum vessel, a wall temperature measuring means for measuring a wall temperature in the vacuum vessel, and a gas temperature measuring means for measuring a gas temperature in the vacuum vessel; A degree control device, a theoretical pressure predicting means for predicting a theoretical pressure in the vacuum vessel after a lapse of a unit time from an arbitrary time, a measured pressure in the vacuum vessel measured by the pressure measuring means after a lapse of a unit time from the arbitrary time, and the theoretical From the difference from the theoretical pressure in the vacuum vessel predicted by pressure prediction means,
A vacuum apparatus comprising: an abnormal gas amount calculating unit that calculates an abnormal gas amount; and an abnormality determining unit that determines an abnormality of the abnormal gas amount. 2. The method according to claim 1, wherein the theoretical pressure predicting means is configured to determine, at the arbitrary time, the amount of gas released from the wall surface in the vacuum vessel, the pressure inside the vacuum vessel measured by the pressure measuring means, the volume of the vacuum vessel, and the vacuum pump. 2. The vacuum apparatus according to claim 1, wherein a theoretical pressure in the vacuum vessel after a lapse of a unit time from the arbitrary time is predicted based on a pumping speed of the vacuum pump and a pumping limit pressure of the vacuum pump. 3. The method according to claim 1, wherein the abnormal gas amount is a sum of a degas amount from a wall surface in the vacuum vessel per unit time and an intrusion gas amount from the outside of the vacuum vessel. 3. The vacuum apparatus according to 2. 4. The vacuum apparatus according to claim 3, wherein the abnormality determining means determines an abnormality in the degassing amount and / or the intruding gas amount based on the abnormal gas amount. 5. The abnormality determination means, when the value of the abnormal gas amount becomes smaller than a predetermined abnormality determination value in a time interval from the start of baking until the abnormal gas amount hardly changes, the degassing is performed. The vacuum apparatus according to claim 4, wherein it is determined that the amount is abnormal. 6. The abnormality determination means sets the value of the abnormal gas amount in advance in a time interval after the start of the baking and after the abnormal gas amount hardly changes until the end of the baking. The vacuum apparatus according to claim 4, wherein when the abnormal gas amount becomes larger than the abnormal determination value, the degas amount and / or the intruding gas amount are determined to be abnormal. 7. The abnormality judging means, when the abnormal gas amount increases without converging to a substantially constant value in a time interval from the end of baking to reaching a target vacuum degree,
The vacuum apparatus according to claim 4, wherein it is determined that the amount of the intruding gas is abnormal. 8. The apparatus according to claim 3, wherein the abnormality determining means determines an abnormality in the degassing amount and / or the intruding gas amount based on a cumulative value of the abnormal gas amount. The vacuum apparatus according to claim 1. 9. The abnormality determining means determines that the degassing amount and / or the intruding gas amount is abnormal if the accumulated value of the abnormal gas amount does not decrease after the baking is completed. The vacuum device as described. 10. The cryopump is used as the vacuum pump, and the theoretical pressure is calculated by the following equation. t: time P (t): theoretical pressure in the vacuum vessel at time t P ₀ : pressure at time t = 0 (pressure in the vacuum vessel measured by pressure measuring means at an arbitrary time) P _eq0 : pressure on the cryopump of the cryopump pressure, constant determined from the gas temperature and the cryo-surface temperature (= vacuum pumping limit coefficient determined by the gas type and pump) S _c: pumping speed factor of the cryopump (= constant) V: the vacuum container volume C _v: vacuum The value obtained from the surface area of the inner wall of the vessel, the thermal velocity of gas molecules, the adsorption time of gas molecules on the inner wall of the vacuum vessel, the probability of gas molecules adhering to the inner wall of the vacuum vessel, and the surface roughness coefficient of the inner wall of the vacuum vessel (= The gas pressure coefficient, the gas temperature, and the gas release coefficient that varies depending on the vacuum vessel. The vessel internal pressure is substituted into P ₀ as an initial vacuum chamber pressure, vacuum device according to any one of claims 1 to 9, wherein calculating a time t after the vacuum vessel theoretical pressure P (t) . 11. From a time after each elapse of a unit time after a predetermined time has elapsed from the start of baking to a baking end time, the abnormal gas amount at the time of each elapse of the unit time is corrected for pressure by the unit time. Calculated as a value,
And, from the baking end time to the time to reach the target vacuum degree, the abnormal gas amount calculated per unit time from the previously calculated and stored baking end time is divided by the abnormal gas amount at the baking end time, and A pressure correction value calculation unit that calculates a value obtained by multiplying the abnormal gas amount at a time every unit time by a time as a pressure correction value per unit time; For each unit time calculated by the gas discharge amount, the pumping speed of the vacuum pump, the pumping limit pressure of the vacuum pump, the degassing amount from the inner wall surface of the vacuum vessel, the volume of the vacuum vessel, and the pressure correction value calculating means. Based on the pressure correction value calculated in the above, the pressure in the vacuum vessel at the time of each elapse of the unit time is set as the initial pressure for the unit time The predicted pressure after the passage of time is predicted, and the predicted pressure is predicted as the initial pressure, and the calculation for predicting the predicted pressure after the next unit time is repeated. A target vacuum degree arrival time predicting means for calculating a time of arrival, and estimating a time from the time of elapse of the unit time to the time of reaching the target vacuum degree as a target vacuum degree arrival time. The vacuum device according to any one of claims 1 to 10. 12. The vacuum pump is a cryopump, and a predicted pressure after a lapse of a unit time is expressed by the following equation: t: time P (t): predicted pressure at time t P ₀ : pressure at time t = 0 (pressure in the vacuum vessel measured by pressure measuring means at an arbitrary time) P _eq0 : pressure and gas on the cryopump surface of the cryopump Constant obtained from temperature and cryosurface temperature (= vacuum pump evacuation limit coefficient determined by gas type and pump) S _c : Evacuation speed of cryo pump (= constant) V: Vacuum container volume C _v : Vacuum container inner wall surface Surface area, thermal motion velocity of gas molecules, adsorption time of gas molecules on the inner wall of vacuum vessel, adhesion probability of gas molecules on the inner wall of vacuum vessel, value obtained from surface roughness coefficient of inner wall of vacuum vessel (= coefficient of gas, temperature of the gas, the gas discharge coefficient varies by vacuum container) P _{x (t):} calculated in a pressure correction value obtained by said pressure correction value calculating means, the target degree of vacuum arrival time predicting means , Once before the predicted pressure P in the iterative calculation (t) is substituted into P _0, according to any one of claims 1 to 11, characterized in that to calculate the predicted pressure P after t time (t) Vacuum equipment. 13. The target vacuum degree arrival time predicting means,
The baking end time is changed, the target vacuum degree arrival time is predicted with respect to the changed baking end time, and the shortest baking end time with the target vacuum degree arrival time is selected as the optimum baking end time. 13. The vacuum apparatus according to claim 11, wherein: 14. A vacuum container, a vacuum control device for controlling the degree of vacuum of the vacuum container, a vacuum pump for exhausting gas in the vacuum container, a baking heater for heating a wall surface in the vacuum container, A pressure measuring means for measuring the pressure of the vacuum vessel, a wall temperature measuring means for measuring the wall temperature in the vacuum vessel, and a method for controlling the degree of vacuum of a vacuum apparatus comprising a gas temperature measuring means for measuring the gas temperature in the vacuum vessel. The theoretical pressure predicting means of the vacuum degree control device predicts a theoretical pressure in a vacuum vessel after a lapse of a unit time from an arbitrary time, and the abnormal gas amount calculating means of the vacuum degree control device calculates a unit pressure from the arbitrary time. Calculating an abnormal gas amount from a difference between a measured pressure in the vacuum vessel measured by the pressure measuring means after a lapse of time and a theoretical pressure in the vacuum vessel predicted by the theoretical pressure predicting means; A method for controlling the degree of vacuum of a vacuum device, wherein the abnormality determining means of the airiness control device determines an abnormality of the abnormal gas amount. 15. The pressure correction value calculation means of the vacuum degree control device, wherein after the elapse of a predetermined time from the start of baking, from the time every unit time elapse to the baking end time, The abnormal gas amount at the time is calculated as a pressure correction value per unit time, and from the baking end time to the time when the target degree of vacuum is reached, is calculated per unit time from the previously calculated and stored baking end time. Divided abnormal gas amount by the abnormal gas amount at the baking end time,
The value obtained by multiplying the abnormal gas amount at the time of the elapse of the unit time is calculated as a pressure correction value for the unit time, and the target degree of vacuum arrival time prediction means of the vacuum degree control device is:
The amount of gas released from the inner surface of the vacuum vessel, the pumping speed of the vacuum pump, the exhaust pressure limit of the vacuum pump, the amount of degassing from the inner wall surface of the vacuum vessel, and the volume of the vacuum vessel at each time the unit time elapses Based on the pressure correction value calculated for each unit time calculated by the pressure correction value calculation means, the pressure inside the vacuum vessel at the time of each elapse of the unit time is set as the initial pressure, and the predicted pressure after the elapse of the unit time is calculated. Predicting, and further using the predicted pressure as the initial pressure, repeat the calculation of predicting the predicted pressure after the next unit time, and calculate the time at which the predicted pressure predicted by the repeated calculation reaches the target vacuum degree. And estimating a time from a time at which the unit time elapses to a time at which the target vacuum degree is reached as a target vacuum degree arrival time. 4 vacuum degree control method for a vacuum apparatus according. 16. A vacuum container, a vacuum control device for controlling the degree of vacuum of the vacuum container, a vacuum pump for exhausting gas in the vacuum container, a baking heater for heating a wall surface in the vacuum container, Pressure measurement means for measuring the pressure of the vacuum vessel, wall temperature measurement means for measuring the wall temperature in the vacuum vessel, and a vacuum control program for a vacuum apparatus provided with gas temperature measurement means for measuring the gas temperature in the vacuum vessel. And a procedure for predicting the theoretical pressure in the vacuum vessel after a lapse of a unit time from an arbitrary time, and the measured pressure in the vacuum vessel and the theoretical pressure in the vacuum vessel measured by the pressure measuring means after a lapse of a unit time from the arbitrary time. And a procedure for calculating an abnormal gas amount based on the difference between the two, and a procedure for determining whether the abnormal gas amount is abnormal. 17. After a predetermined time elapses from the start of baking, from the time every unit time elapse to the baking end time, the abnormal gas amount at the time every unit time elapse is corrected by the pressure correction per unit time. Calculated as a value,
And, from the baking end time to the time to reach the target vacuum degree, the abnormal gas amount calculated per unit time from the previously calculated and stored baking end time is divided by the abnormal gas amount at the baking end time, and Calculating a value obtained by multiplying the abnormal gas amount at each time unit time by a time as a pressure correction value per unit time; and The pumping speed of the vacuum pump, the pumping limit pressure of the vacuum pump, the degassing amount from the inner wall surface of the vacuum vessel, the volume of the vacuum vessel, and the unit time calculated by the pressure correction value calculating means. Based on the pressure correction value, the predicted pressure after the elapse of the unit time is set as the initial pressure with the pressure in the vacuum vessel at the time of the elapse of the unit time. Predict the force, furthermore, with the predicted pressure as the initial pressure, repeat the calculation to predict the predicted pressure after the next unit time, the time when the predicted pressure predicted by the repeated calculation reaches the target vacuum degree And estimating the time from the time of elapse of each unit time to the time of reaching the target vacuum degree as a target vacuum degree arrival time. program. 18. A vacuum container, a vacuum control device for controlling the degree of vacuum in the vacuum container, a vacuum pump for exhausting gas in the vacuum container, a baking heater for heating a wall surface in the vacuum container, Claims: 1. A vacuum apparatus comprising: a pressure measuring means for measuring a pressure of a gas; a wall temperature measuring means for measuring a wall temperature in the vacuum vessel; and a gas temperature measuring means for measuring a gas temperature in the vacuum vessel. A vacuum apparatus, wherein the vacuum control program for a vacuum apparatus according to claim 16 or 17 is installed.