JP3657873B2 - Control equipment for plasma equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device for a plasma-using device, and more particularly to a control device for a plasma-using device capable of controlling with high accuracy and excellent stability.
[0002]
[Prior art]
The characteristics of plasma itself in plasma-based devices have not been fully elucidated. For this reason, it is difficult to obtain a predetermined result by controlling the process parameters in accordance with variations in process characteristics. In conventional plasma-based equipment, there is a method for controlling the process parameters set at the start of production to be constant. It has been adopted.
[0003]
On the other hand, in plasma-based equipment for manufacturing semiconductor devices, the state of the reactor itself changes due to reaction products accumulated in the reactor during manufacturing, and the plasma processing characteristics change over time. For this change over time, it is necessary to open the reactor and perform initialization work such as cleaning or parts replacement.
[0004]
[Problems to be solved by the invention]
In recent years, the concept of APC (Auto Process Control) has been introduced to control devices for plasma-using devices, and process control using various measuring instruments has been attempted. However, there is an interaction and a trade-off between the process parameters that determine the state of the plasma treatment. For this reason, as described above, effective process control has not been realized in plasma-based equipment.
[0005]
On the other hand, the method of controlling using multivariate analysis requires controlling a plurality of process parameters for one process characteristic. A method of controlling a plurality of process parameters for one process characteristic requires complicated calculation, and verification of the calculation result requires a huge amount of work, and is difficult to put into practical use.
[0006]
The present invention has been made in view of the above problems, and provides a plasma apparatus control apparatus that is effective even when there is an interaction between process parameters.
[0007]
[Means for Solving the Problems]
The present invention employs the following means in order to solve the above problems.
[0008]
A first, second, and third communication link connected to each other; a plasma state detector that detects a state of plasma generated in a vacuum processing chamber of a plasma-using device connected to the first communication link; A processing object state detector for detecting a state of a processing object placed on a mounting table disposed in a vacuum processing chamber, and a utility detector for detecting a gas supply state of a peripheral device for supplying a processing gas to a plasma utilization device; An apparatus controller and a plasma utilization device for controlling a plasma utilization device based on numerical information detected by the plasma state detector, the workpiece state detector and the utility detector connected to the second communication link. A utility controller for controlling peripheral equipment for supplying the processing gas; an energy control device connected to the third communication link; and A device controller connected to the second communication link based on numerical information detected by the plasma state detector, the workpiece state detector and the utility detector connected to the first communication link, Based on the control numerical information information respectively calculated by the utility controller, an energy control device connected to the third communication link and a control device for the plasma utilizing device for controlling the utility control device, each of the controllers being mainly a predetermined Numerical information that affects only the process characteristics is selected as control information.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a diagram showing a control device for a plasma-using device according to an embodiment of the present invention. In the figure, 10 is a first communication link, 11 is a second communication link, 12 is a third communication link, and the first communication link and the third communication link are mutually connected via the second communication link. Connect to. 1 is an apparatus controller for controlling the plasma processing apparatus, 3 is an apparatus state detection sensor for detecting the apparatus state (gas pressure in the vacuum processing chamber, plasma fluctuation, etc.), and 4 is the state of an object to be processed such as a semiconductor wafer. A processing object state detection sensor for detecting (position, temperature, processing speed, etc. of the processing object), and 5 is an energy control device for controlling energy supplied to a plasma generation device or the like. 6 is a utility control device that controls utility equipment that is a peripheral device of the plasma processing apparatus such as an introduction gas supply device, 7 is a production stabilization controller that manages the plasma processing process and its preceding and following processes, and 8 is a utility that controls the utility equipment. A controller 9 is a tact management controller that manages the processes of various processing apparatuses in a coordinated manner.
[0010]
13 is an energy monitor that monitors the amount of energy supplied to the plasma generator or the cooling device of the plasma generator, 14 is a monitor that measures the utility status (introduction gas flow rate, gas pressure, etc.), 15 the number of processed wafers or dummy wafers It is a counter that counts the number of sheets used. Reference numeral 16 denotes an emission spectrometer that analyzes light emission based on a reaction product generated during the plasma processing, and reference numeral 17 denotes a mass analyzer that analyzes the reaction product generated during the plasma processing, both of which are installed in the reaction chamber. 18 is a plasma probe, and 19 and 20 are communication lines connecting the first communication link 10 and the second communication link 11, and the second communication link 11 and the third communication link 12, respectively. 21 is an apparatus control man-machine interface for an operator to input processing conditions (etching conditions, etc.) of the plasma processing apparatus, and 22 is a man-machine interface for performing maintenance of the plasma processing apparatus (transfer test of the wafer transfer apparatus, etc.). , 30 is a host computer that integrates and manages a plurality of semiconductor manufacturing apparatuses, and manages apparatus information, processing object information, production information, etc. of the manufacturing line. Reference numeral 90 denotes a tact management controller connected to a link for managing other semiconductor manufacturing apparatuses.
[0011]
As shown in the figure, the first communication link 10 includes an apparatus state detection sensor 3, an object state detection sensor 4, an energy monitor 13, a utility monitor 14, a counter 15, a mass analyzer 17, and an emission spectrometer 16. The plasma probe 18 is connected. Measurement value information measured by these measuring devices is transmitted to the second communication link via the communication line 19.
[0012]
The second communication link 11 is connected to a controller such as the device controller 1, the production stabilization controller 7, the utility controller 8, and the tact management controller 9. These controllers receive the numerical information, and generate control numerical information for various control devices based on the received numerical information.
[0013]
An energy control device 5 and a utility control device 6 are connected to the third communication link 12. These control devices receive the control numerical information, and control the energy control device and the peripheral device based on the received control numerical information.
[0014]
The device controller 1, the production stabilization controller 7, the utility controller 8, and the tact management controller 9 connected to the second communication link respectively fetch numerical information detected by various measuring devices connected to the first communication link 10, Predetermined arithmetic processing is performed to generate control numerical information. The various controllers control the energy control device and peripheral devices based on the control numerical value information, and transmit the calculation processing result information to other controllers. The other controller that has received the arithmetic processing result information can perform arithmetic processing again based on the information to generate control numerical value information. The tact management controller 9 can transmit and receive the calculation result information to and from other tact management controllers 90 to perform process progress management.
[0015]
Thus, according to this embodiment, distributed computer control becomes possible. The shape of the communication link can be a line shape or other shapes in addition to the loop shape shown in the figure.
[0016]
Next, an example of processing a Poly-Si gate electrode by applying the control device for the plasma-using device to a dry etching device will be described. It is known that the etching rate, which is one of process characteristics, decreases when processing of a Poly-Si wafer is continued with a dry etching apparatus.
[0017]
Factors that affect process characteristics are as follows: (1) Gas components supplied from reaction products deposited in the reactor (vacuum processing chamber) by processing; (2) Effective earth area of high-frequency discharge by deposition of reaction products (3) Impedance of electrode and reactor wall with attached reaction products, (4) Subtle change in gas pressure due to temperature rise in each part of reactor, (5) Reaction production attached to electrode surface on which wafer is mounted Examples include impedance changes with respect to wafer bias due to objects, and fluctuations in high-frequency output based on (6) atmosphere and temperature rise of the reactor itself.
[0018]
On the other hand, constant control as process parameters of the dry etching apparatus includes (1) high frequency output, (2) wafer bias output, (3) supply gas flow rate, (4) reactor internal pressure, (5) electrode cooling water. Temperature and cooling water flow rate, (6) Temperature adjustment water temperature and flow rate of reactor wall surface.
[0019]
Examples of the process parameters effective for improving the decrease in the etching rate include (1), (2), (3), (4), (5), and (6). However, if the high frequency output of (1) is increased, the gas flow rate of (3) is increased, or the gas pressure of (4) is increased, the plasma characteristics change and the etching species increase. For this reason, the etching rate returns to the initial value, but the etching shape, which is another process characteristic, or the etching rate ratio with the base film or the photoresist greatly changes.
[0020]
Moreover, when the electrode cooling water temperature of said (5) is raised, reaction efficiency can be improved and an etching rate can be raised. However, this method is difficult to control due to the large time constant of the control system, and may cause etching shape defects such as side etching and notches. In addition, the adjustment of the temperature adjustment water temperature of the wall surface in (6) has a larger time constant than in the case of (5) and cannot be controlled.
[0021]
However, it has been found that the method (2) of increasing the wafer bias output can recover the etching rate with little influence on other process characteristics. Therefore, a film thickness monitor that can measure the etching rate during etching is newly provided, and the wafer bias output is increased in accordance with the decrease in the etching rate, thereby preventing changes in the etching rate characteristics and maintaining the initial characteristics for a long time. be able to.
[0022]
Next, an example will be described in which the control device of the plasma-using device is applied to a dry etching apparatus and a hole is formed in the interlayer insulating film of the SiO ₂ film. It is known that the etching rate, which is one of the process characteristics, decreases when the hole processing of the SiO ₂ wafer is continued with a dry etching apparatus. Factors affecting the process characteristics are: (1) gaseous components supplied from reaction products deposited in the reactor by treatment, and (2) reduction in effective earth area of high-frequency discharge due to deposition of reaction products. (3) Impedance change of electrode or reactor wall to which reaction product is attached, (4) Subtle change of gas pressure due to temperature rise in each part of reactor, (5) Reaction product attached to electrode surface on which wafer is mounted Examples include impedance changes with respect to wafer bias, and (6) fluctuations in high-frequency output due to the temperature rise of the atmosphere and reactor itself.
[0023]
On the other hand, constant control as process parameters of the dry etching apparatus includes (1) high frequency output, (2) wafer bias output, (3) supply gas flow rate, (4) reactor internal pressure, (5) electrode cooling water. Temperature and cooling water flow rate, (6) Temperature control water temperature and flow rate of reactor wall surface. First, the above-mentioned (1), (2), (3), (4), (5) and (6) can be cited as effective process parameters for improving the decrease in the etching rate. However, if the high frequency output of (1) is increased or the gas pressure of (4) is increased, the plasma characteristics change and the etching species increase, so that the etching rate can be restored to the initial value. The etching characteristics, which are process characteristics, and the etching rate ratio with the underlying film and photoresist are greatly changed. Further, since the wafer bias output of (2) is very large as compared with the Poly-Si gate etching, if the etching rate is increased as the etching rate is recovered, the etching shape which is another process characteristic is greatly affected. Further, (5) and (6) have a large time constant and cannot be controlled as described in the previous example. However, it has been found that the method (3) can recover the etching rate with little influence on other process characteristics by increasing the flow rate of oxygen among fluorocarbon and oxygen as the supply gas species. . Therefore, a film thickness monitor that can measure the etching rate during etching is newly provided, and the oxygen gas flow rate is increased by a small amount in accordance with the decrease in the etching rate, thereby preventing changes in the etching rate characteristics and maintaining the initial characteristics for a long time. can do.
[0024]
Next, an example of processing the aluminum alloy film wiring by applying the control device of the plasma utilizing device to a dry etching device will be described. It is known that when the wiring processing of the aluminum alloy film wafer is continued with a dry etching apparatus, the etching shape, which is one of the process characteristics, tapers from the vertical. Factors affecting the process characteristics are: (1) the gas component supplied from the reaction product deposited in the reactor by the treatment, and (2) the effective earth area of the high-frequency discharge due to the deposition of the reaction product. Reduction, (3) Impedance change of electrode and reactor wall to which reaction product is attached, (4) Subtle change of gas pressure due to temperature rise in each part of reactor, (5) Reaction product attached to electrode surface on which wafer is mounted (6) Variation in high-frequency output due to an increase in temperature of the atmosphere and reactor itself. Among these, the gas component supplied from the attached reaction product (1) has the greatest influence.
[0025]
On the other hand, constant control as process parameters includes (1) high frequency output, (2) wafer bias output, (3) supply gas flow rate, (4) reactor internal pressure, (5) electrode cooling water temperature and cooling water. Flow rate, (6) Temperature adjustment water temperature and flow rate of reactor wall surface. Examples of the process parameters effective for improving the deterioration of the etching shape include the above (1), (2), (3), (4), (5) and (6). However, if the high-frequency output (1) is increased or the wafer bias output (2) is increased, the selection ratio with the resist is greatly affected. The deterioration of the etching shape can be prevented by increasing the supply gas flow rate in (3) to make the gas component supplied from the attached reaction product relatively equivalent to the initial etching stage, but the plasma state changes. As a result, other process characteristics are affected. Further, (5) and (6) have a large time constant and cannot be controlled as described in the previous example. However, in the case of (4), it was found that the etching shape can be recovered with little influence on other process characteristics by slightly reducing the pressure in the reactor. Therefore, a dimension monitor that can measure the width of the etched wiring dimension during etching is newly provided, and the pressure inside the reactor is reduced according to the tapering of the etching shape, thereby preventing the deterioration of the etching shape and the initial characteristics. Can be maintained for a long time.
[0026]
In each of the above examples, the initial characteristics can be maintained for a long time not by providing a new monitor in the reactor, but also by controlling the control parameters based on offline measurement results.
[0027]
As described above, according to the present embodiment, first, one process characteristic that greatly affects the inhibition of stability in plasma processing is extracted, and a plurality of process parameters that change the process characteristic are determined. Then, a process parameter that has the least influence on other process characteristics other than the extracted process characteristics is selected instead of the process parameter that has the largest influence on the process characteristics, and is selected as the first control. It is a parameter. Next, a process parameter is selected in the same procedure for other process characteristics that inhibit the stability in the plasma processing, and this is set as the second parameter. In the same manner, process parameters for characteristics that require control are selected. Note that the selection of these process parameters may be performed by a computer using a method such as the Taguchi method. In this way, by controlling the selected process parameters, multiple process characteristics that hinder the stability of the plasma treatment can be controlled with minimal interaction, and the initial process characteristics can be controlled over time. Can be maintained.
[0028]
Furthermore, since process parameters that do not affect other process characteristics as much as possible are selected and controlled, it is possible to save time and effort for verifying changes with time. In addition, it is possible to suppress changes in plasma characteristics over time without directly controlling comprehensive plasma characteristics that have not been elucidated.
[0029]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a plasma apparatus control apparatus that is effective even when there is an interaction between process parameters.
[Brief description of the drawings]
FIG. 1 is a diagram showing a control device for a plasma-using device according to an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 apparatus controller 3 apparatus state detection sensor 4 to-be-processed state detection sensor 5 energy control apparatus 6 utility control apparatus 7 production stabilization controller 8 utility controller 9, 90 tact management controller 10 1st communication link 11 2nd communication link 12 Third communication link 13 Energy monitor 14 Utility 15 Counter 16 Emission spectroscope 17 Mass spectrometer 18 Plasma probe 19, 20 Communication line 21 Device control man-machine interface 22 Maintenance man-machine interface 30 Host computer

Claims (2)

First, second and third communication links connected to each other;
A plasma state detector connected to the first communication link for detecting a state of plasma generated in a vacuum processing chamber of a plasma utilizing device, and an object to be processed mounted on a mounting table disposed in the vacuum processing chamber A processing state detector for detecting the state and a utility detector for detecting a gas supply state of a peripheral device for supplying a processing gas to the plasma utilization device ; and
Based on the numerical information detected by the plasma state detector, the workpiece state detector, and the utility detector connected to the second communication link, the apparatus controller that controls the plasma using device and the plasma using device process A utility controller that controls peripheral devices that supply gas ;
An energy control device and a utility control device connected to the third communication link ;
Based on the numerical information detected by the plasma state detector, workpiece state detector and utility detector connected to the first communication link, the device controller and utility controller connected to the second communication link respectively calculated A control device for a plasma utilizing device that controls an energy control device and a utility control device connected to a third communication link based on control numerical information information, wherein each controller mainly affects only predetermined process characteristics. A control device for a plasma-using device, wherein numerical information to be given is selected as control information. In the control apparatus of the plasma utilization apparatus of Claim 1,
Information selected by the controllers as information mainly affecting only predetermined process characteristics includes high frequency output, wafer bias output, supply gas flow rate, reactor internal pressure, electrode cooling water temperature and cooling water flow rate, and reactor wall temperature adjustment. A control device for a plasma-using device, characterized by being one of water temperature and flow rate.

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