JP3534716B2 - Plasma processing method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus and a plasma processing method, and in particular, it is suitable for performing a process such as etching on a sample by using high density plasma.
The present invention relates to a plasma processing apparatus and a plasma processing method.

[0002]

2. Description of the Related Art As a conventional plasma processing apparatus, for example, a microwave plasma processing apparatus is used as described in Semiconductor Plasma Process Technology (edited by Takuo Sugano, published by Sangyo Tosho, (1980), P139). There is a discharge chamber made of quartz in a waveguide that propagates the plasma, and plasma is generated in the discharge chamber by the action of an external magnetic field and a microwave electric field generated by a coil arranged outside the discharge chamber. Then, it becomes possible to perform processing such as etching on the surface of the semiconductor wafer using the plasma.

In such a microwave etching apparatus, a non-magnetic and electrically conductive material to serve as a waveguide is required as a processing chamber in order to introduce a microwave and introduce an external magnetic field into the processing chamber. is there. Therefore, a metal such as aluminum (Al) or stainless steel (SUS) is generally used as the wall material of the processing chamber.

By the way, the stainless steel and other metals forming the wall surface of the processing chamber are scraped and scattered by the plasma, and become a pollution source together with the heavy metal contained therein.

On the other hand, Japanese Patent Laid-Open No. 4-229619 discloses a method in which a conductive coating capable of protecting a metal surface from chemical corrosion by a reaction gas used in a processing chamber is formed on the inner metal surface. It is shown. this is,
When plasma etching is performed using halogen gas such as chlorine as the processing gas, the metal wall of the processing chamber may be corroded. Therefore, a protective film is formed by coating on the metal inner wall surface of the processing chamber. Is. The metal in the processing chamber is aluminum, and the coating material is Ti
N, InSn, SiC, TiC, TaC and the like are listed. The thickness of the coating layer is 0.2 μm to 1 μm
It is said to extend.

Further, in Japanese Patent Laid-Open No. 63-138737, a dry etching apparatus having a counter electrode inside the chamber is detachable from the chamber in order to clean the inner surface of the contaminated chamber. Insulation is shown covering the interior of the chamber. As an insulating material,
Examples thereof include alumite, alumina spraying, Teflon (registered trademark), ceramics and the like.

[0007]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the conventional technique described in Japanese Patent No. 619, it is possible to protect the metal surface from the viewpoint of chemical corrosion due to the reaction gas used in the processing chamber. However, as is clear from the description in column 5 of the above publication as typical plasma etching process conditions, the temperature during plasma processing is limited to a relatively low temperature range of about 10 ° C to about 70 ° C. Has been done. If the temperature of the aluminum forming the processing chamber is 100 ° C.
It is considered that when the temperature rises above the above range, cracks may occur in the coating film on the aluminum surface due to thermal expansion of aluminum. In order to avoid the occurrence of cracks, the coating film has to be thin. However, when the film thickness is reduced, the coating film is corroded in a short time by the reaction gas accompanying the plasma etching, and the function of the coating film is not fulfilled. For example, according to experiments by the inventors, in the case of SiC, about 0.0 per minute is obtained by etching.
There is data that it will be cut by 5 μm. Therefore, 0.2
With a thickness of about 1 μm to 1 μm, the coating layer is destroyed and disappears after several hours, in other words, when several hundred samples are processed. As a result, the metal surface of the inner wall of the processing chamber is exposed to the plasma, and is abraded by the plasma or chemically reacts to be deteriorated, which becomes a source of heavy metal contamination or deteriorates the characteristics of the processing chamber.

On the other hand, in the invention described in the above-mentioned Japanese Patent Laid-Open No. 63-138737, the contaminated insulating material is removed from the chamber, cleaned, and then mounted again in the chamber for use. However, the insulating material is used. When the above is mounted on the inner surface of the chamber, there is a problem that the temperature of the insulating material mounted during the plasma processing fluctuates and the plasma processing characteristics fluctuate significantly.

An object of the present invention is to prevent the surface of the processing chamber from being altered by plasma and to become a source of heavy metal pollution, and to keep the temperature of the surface of the processing chamber at a desired temperature to stabilize the plasma processing characteristics with time. Another object of the present invention is to provide a plasma processing apparatus and a plasma processing method.

[0010]

Means for Solving the Problems The present invention comprises a plasma generating apparatus, a reduced pressure can process chamber, a processing gas supply unit for supplying a gas into the processing chamber, a sample stage and a vacuum exhaust device for holding a sample In the plasma processing method, wherein the processing chamber is provided with an outer cylinder capable of withstanding reduced pressure and an inner cylinder arranged inside the outer cylinder, the sample is plasma-treated by a plasma processing apparatus, wherein the inner cylinder is made of a non-magnetic material. Configured to be interchangeable
The temperature of the inner cylinder is monitored to treat the sample.
The desired internal cylinder temperature and the
The monitor temperature of the inner cylinder is compared and calculated, and based on the calculation result.
Therefore, the temperature of the inner cylinder is controlled by controlling the temperature of the outer cylinder.
Is controlled to a predetermined value .

Another feature of the present invention is a plasma generator, a processing chamber capable of decompressing, a processing gas supply device for supplying a gas to the processing chamber, a sample stage for holding a sample, and a vacuum exhaust device.
And a plasma processing method for plasma-treating a sample with a plasma processing apparatus, wherein the processing chamber has an outer cylinder that withstands reduced pressure, and an inner cylinder arranged inside the outer cylinder,
The inner cylinder is made of a non-magnetic material and is replaceable.
And the temperature of the inner cylinder is monitored, and a sample with a multilayer film structure is
In the processing of
Depending on the film quality of each structure, processing gas species, and discharge conditions
Comparing the desired inner cylinder temperature with the monitor temperature of the inner cylinder
And controlling the temperature of the outer cylinder based on the calculation result.
To control the inner cylinder temperature to a predetermined value .

Another feature of the present invention is that a plasma generator, a decompressible processing chamber, a processing gas supply device for supplying a gas to the processing chamber, a sample stage for holding a sample, and a vacuum exhaust device.
And a plasma processing method for plasma-treating a sample with a plasma processing apparatus, wherein the processing chamber has an outer cylinder that withstands reduced pressure, and an inner cylinder arranged inside the outer cylinder,
The inner cylinder is made of a non-magnetic material and is replaceable.
And monitor the temperature of the inner cylinder and process the lot.
The desired inner cylinder temperature and the inner cylinder previously input according to
Comparing calculation with the monitor temperature of
By controlling the temperature of the outer cylinder, the inner cylinder temperature can be
To compensate for process changes early in the lot .

Another feature of the present invention is that a plasma generator, a processing chamber capable of decompressing, a processing gas supply device for supplying a gas to the processing chamber, a sample stage for holding a sample, and a vacuum exhaust device.
And a plasma processing method for plasma-treating a sample with a plasma processing apparatus, wherein the processing chamber has an outer cylinder that withstands reduced pressure, and an inner cylinder arranged inside the outer cylinder,
The inner cylinder is made of a non-magnetic material and is replaceable.
And monitor the temperature of the inner cylinder and process the lot.
According to the desired inner cylinder temperature pattern
The monitor temperature of the inner cylinder is compared and calculated, and the calculated result is obtained.
By controlling the temperature of the outer cylinder based on
The temperature of the inner cylinder during processing is controlled to process the sample during the processing of one lot.
It is to stabilize the physical performance .

Since the inner cylinder made of a material that does not contain heavy metals such as ceramics is used as the inner wall of the processing chamber, the metal surface such as aluminum forming the outer cylinder is not exposed during the processing of the wafer, and therefore the metal is removed by the plasma. It does not become a source of heavy metal contamination on the wafer by being scraped or altered. On the other hand, since the inner cylinder has a lower thermal conductivity than the outer cylinder, the temperature of the inner cylinder during the etching process, in other words, the surface temperature of the processing chamber is 200 ° C. to 3 ° C. if no control is performed.
Reach 50 ° C or higher. In the present invention, since the temperature of the inner cylinder is controlled to a desired value, for example, a desired value between 100 ° C. and 350 ° C., the surface temperature of the processing chamber is also maintained at the desired value, so that the etching characteristics are stable. Becomes

Further, the process can be stabilized by controlling the surface temperature of the inner cylinder in a desired pattern.

The inner surface of the material forming the inner cylinder is
When using a material that is slightly scraped by plasma, the inner surface of the inner cylinder is constantly renewed to a new surface, so there is no risk of contamination due to alteration of the inner surface, and the characteristics of the processing chamber change little over time. Absent. Also, since the inner cylinder does not contain heavy metals, there is no concern that it will become a pollution source even if it is scraped.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

First, FIG. 1 is a front view in which a part of a microwave plasma processing apparatus according to an embodiment of the present invention is longitudinally cross-sectioned, and FIG. 2 is an enlarged view of a main part thereof. Reference numeral 1 is a magnetron as a microwave oscillation source, and 2 is a microwave waveguide. Reference numeral 3 is a quartz plate for vacuum-sealing the processing chamber 4 and supplying microwaves to the processing chamber 4. The processing chamber 4 includes, for example, an outer cylinder 5 made of high-purity aluminum (Al) that withstands a reduced pressure, and a silicon carbide (Si) arranged inside the outer cylinder 5.
The inner cylinder 6 is made of ceramic such as C). Since the inner surface of the processing chamber 4 is an insulator and the outside is a conductor, the processing chamber 4 also serves as a waveguide. 7 is a first solenoid coil for supplying a magnetic field, 8 (8A, 8B)
Is a second solenoid coil that supplies the magnetic field. The processing chamber 4 is evacuated by a vacuum pump connected to the vacuum chamber 9. Reference numeral 10 denotes a sample table on which a wafer 11 to be processed such as etching is placed, and a high frequency power source 12 is connected thereto. A processing gas supply system 13 supplies a processing gas for performing processing such as etching and film formation into the processing chamber 4.

There is a gap G14 of about 0.1 to 2 mm between the outer cylinder 5 and the inner cylinder 6, and a heat transfer gas for temperature control is introduced through a gas supply system 15 between them. Gas supply system 15
Is equipped with a gas source 16, a pressure control valve 17, a pressure detector 18, a pressure command instructing means 19, and a control circuit 20. The pressure detector 18 detects the pressure P in the gap 14 and sets this pressure P to a desired value. The opening degree of the pressure control valve 17 is controlled so as to be maintained at.

The inner cylinder 6 is supported by a support 32.
It is detachably supported on the outer cylinder 5 so that it can be replaced with a new one when it is consumed by a certain amount.

A heater 21 for heating the processing chamber 4 is arranged around the outer cylinder 5, a temperature detector 23 detects the temperature T of the inner cylinder 6, and a temperature controller 22 detects the temperature of the outer cylinder 5. The temperature T0 is controlled. This heater 21
The temperature T0 of the outer cylinder 5 and the pressure of the gap 14 are maintained at predetermined values to maintain the temperature T of the inner cylinder 6 at a predetermined value.

In the plasma etching process, while the process gas is introduced into the process chamber 4 from the gas supply system 13 at a predetermined flow rate, the pressure in the process chamber 4 is adjusted to a predetermined process pressure by evacuating the process gas by a vacuum pump. Adjust. Further, the heater 21, the gas supply system 15, the temperature controller 2
2, the temperature T0 of the outer cylinder 5, the temperature T of the inner cylinder 6, and the pressure P of the gap 14 are controlled to predetermined values.

On the other hand, the wafer 11 to be processed is placed and held on the sample table 10, the magnetron 1 and the first and second solenoid coils 7 and 8 are turned on, and microwaves are guided to the processing chamber 4. Plasma 100 is generated in the processing chamber 4, and the wafer 11 is subjected to processing such as etching.

According to the present invention, during processing of the wafer 11,
Since the metal surface such as aluminum is not exposed as the inner wall of the processing chamber 4, the metal is not ground or altered by the plasma 100, and does not become a heavy metal contamination source for the wafer 11.

On the other hand, the inner surface of SiC forming the inner cylinder 6 is gradually scraped by the plasma 100. However, since it does not contain heavy metals, there is no risk of becoming a pollution source even if it is scraped. Rather, since the inner surface of the inner cylinder 6 is constantly updated to a new surface by being scraped, there is no risk of contamination due to alteration of the inner surface, and the characteristics of the processing chamber 4 hardly change with time. The removed SiC component is
The processing chamber 4 is evacuated by a vacuum pump.

During the etching process, the temperature of the inner cylinder rises due to the heat generated in the processing chamber. If no control is performed, the temperature T of the inner cylinder becomes 200 ° C. to 350 ° C. or higher. On the other hand, the etching characteristics in the plasma etching process are greatly affected by the temperature of the inner surface of the inner cylinder 6. That is, the reaction between the inner cylinder 6 and the etching gas changes due to the change in the surface temperature of the inner cylinder 6, and the atmosphere of the etching gas changes, so that the etching characteristics are not stable. For example, when the temperature of the cylinder 6 changes, the composition and amount of the deposited substance on the wall change, and the reaction rate with the wall changes, which changes the composition in the plasma, resulting in an etching characteristic. Not stable.

In the present invention, by controlling the temperature T0 of the outer cylinder 5 and the pressure P of the gap 14 by the heater 21, the surface temperature T of the inner cylinder is 100 ° C to 350 ° C, preferably 150 ° C to 300 ° C. Control to the desired value between ° C. According to the present invention, since the temperature T on the surface of the inner cylinder 6 is maintained at a predetermined value, the etching characteristic becomes stable. Also,
Since the temperature of the inner cylinder 6 is maintained at a predetermined value and the reaction rate of the plasma on the inner surface of the inner cylinder 6 is stabilized, the amount of the surface of the inner cylinder 6 scraped by etching becomes constant. As a result, the characteristics of the processing chamber 4 are also stable.

FIG. 3 shows the temperature control function of the inner cylinder 6 by the temperature controller 22. As an example, it is shown that the temperature T of the inner cylinder 6 is brought close to T0 by maintaining the temperature of the outer cylinder 5 at T0.

In this case, as shown in FIG. 4, by increasing the pressure P in the gap 14, the difference between the temperatures T and T0 can be reduced. Specifically, the gap 14 is 1 mm, and the gap 14 is H
When the e gas is supplied and the gas pressure is controlled to 10 Torr, when the heat input amount to the inner cylinder 6 is equivalent to 0 to 300 W, the outer cylinder 5
The temperature of the inner cylinder 6 to 150 ° C ± 150 ° C
It is possible to keep at 20 ° C.

The optimum value of the desired temperature of the inner cylinder varies depending on the combination of the material of the cylinder, the quality of the film to be processed, the type of processing gas, the discharge conditions and the like.

For example, when a CF type gas is used as a processing gas and quartz is used for a cylinder to process the resist-coated oxide film sample shown in FIG. 12, when the temperature of the inner cylinder is not controlled, as shown in FIG. As the number of processed samples increases, the inner cylinder gradually receives heat from the plasma and gradually rises to reach the saturation temperature. At this time, the fluctuation of the etching rate of the oxide film is small, but the etching rate of the resist gradually decreases as the temperature of the inner cylinder rises, and the etching rate of the resist becomes stable when the temperature of the inner cylinder is saturated.

On the other hand, if the temperature of the inner cylinder is kept at the saturation temperature of FIG. 13 in advance, a stable resist etching rate can be obtained from the beginning of the number of processed samples.

If the temperature of the inner cylinder is maintained at the initial temperature instead of the saturation temperature shown in FIG. 13, the etching rate at the initial number of processed samples can be obtained.

The narrower the gap 14, the better the heat transfer by the gas, but the effect can be obtained up to a gap of about 2 mm.

The material of the inner cylinder 6 in the embodiment is a non-magnetic material for microwave discharge using a magnetic field, and it is necessary that it is not altered by plasma and does not contain heavy metals. To meet this condition, carbon C, silicon (Si), quartz (SiO2), alumina (Al2O)
Materials such as 3) may be used, but an aluminum material may be used depending on the content of plasma treatment.

Further, the inner cylinder 6 is required to have mechanical strength and durability of a predetermined value or more. That is, the thickness of the SiC in the embodiment forming the inner cylinder 6 has a mechanical strength capable of withstanding an external force acting during plasma processing, and can withstand a large amount of wafer processing while being scraped by the plasma 100. It must be durable. It is sufficient that the thickness of SiC is 2 to 10 mm in order to practically withstand the processing of tens of thousands of wafers, assuming that it is etched by about 0.05 μm per minute by etching.

In the embodiment shown in FIG. 1, the surface temperature of the quartz plate 3 is set to 1 by the same method as the temperature control of the inner cylinder 6.
It is preferable to control the temperature to 00 ° C to 350 ° C.

FIG. 5 is a vertical sectional view of a microwave plasma processing apparatus according to another embodiment of the present invention. The processing chamber 4 is composed of an outer cylinder 5 made of, for example, high-purity aluminum and a ceramic inner cylinder 6 arranged inside the outer cylinder 5. The inner surface of the processing chamber 4 has a reverse taper shape, and the inner cylinder 6 has a truncated cone shape. There is a gap 14 between the outer cylinder 5 and the inner cylinder 6. In the gap 14, as shown in FIG.
The corrugated plate 30 made of aluminum is arranged, and the corrugated plate 30 is in contact with the outer cylinder 5 and the inner cylinder 6 by the spring force. A heater 21 for heating is arranged on the outer circumference of the outer cylinder 5. The lower end portion of the inner cylinder 6 is held by the support portion 32 via the spring 31. A spring 33 is also provided at the upper end of the inner cylinder 6, and the corrugated plate 30, the outer cylinder 5, and the inner cylinder 6 are provided by these springs 31, 33.
The contact force of is increased. The springs 31 and 33 are also the outer cylinder 5
It also has a function of absorbing a difference in thermal expansion between the inner cylinder 6 and the inner cylinder 6.

Also in this embodiment, the function of the inner cylinder 6 made of SiC is the same as that of the above-mentioned embodiment. This embodiment is characterized in that the heat transfer between the outer cylinder 5 and the inner cylinder 6 is a combination of the contact heat conduction method using the corrugated plate 30 and the gas conduction method using the gas in the gap 14. According to this embodiment, the surface temperature T of the surface of the processing chamber, that is, the inner cylinder 6
Is maintained at a value having a small difference with respect to the temperature T0 of the outer cylinder 5, so that the etching characteristic becomes stable.

In the embodiments of FIGS. 1 to 5 described above, the temperature of the inner cylinder 6 need not be directly detected (if indirectly detected). However, by adding the temperature detector 23 to the inner cylinder 6, there are the following effects.

(1) In order to control the temperature T of the inner cylinder 6 more accurately, the pressure in the gap 14 can be made variable or the temperature of the outer cylinder 5 can be finely adjusted. Is improved.

(2) The temperature of the inner cylinder 6 can be monitored, and when the temperature of the inner cylinder 6 is out of a predetermined range, an alarm output such as not performing plasma processing can be output or the plasma processing can be stopped.

Although the heater heating device has been described as the temperature control function of the outer cylinder in the above-described first to fifth embodiments, the temperature control is performed from cooling to room temperature or below to heating by circulating the temperature-controlled circulating liquid in the outer cylinder. The range can be widened,
The temperature controllability of the inner cylinder is further improved.

FIG. 7 shows an example of application to a parallel plate plasma etching apparatus as another embodiment of the present invention. In this apparatus, the processing chamber 4 as a vacuum container is composed of a substantially closed metal reaction consisting of an outer chamber 40, a top plate 41, a side wall 42 and a bottom plate 43. A pair of opposed parallel plate electrodes (an anode grounded to the inner wall of the outer chamber 40, a cathode 47 attached to the outer chamber 40 via an insulator 46) are provided in the vacuum container, and high frequency energy is supplied to the cathode 47. There is a high frequency power supply 48. Furthermore, there is a connection 44 to a vacuum pump for partially evacuating the processing chamber 4, and a reactive gas supply source for supplying the reactive gas to the processing chamber 4 through a valve-controlled conduit 45. The wafer 11 to be etched is
It is mounted on the cathode 47.

An inner cylinder 49 made of SiC is provided on the inner surface of the outer chamber 40, that is, the upper plate 41, the side wall 42, and the bottom plate 4.
3 is formed on the inner surface. There is a gap 50 between the outer chamber 40 and the inner cylinder 49, and a heat transfer gas for temperature control is introduced between the gap 50 and the gas supply system. The gas supply system includes a gas source, a pressure control valve, a pressure detector, a pressure command instructing means, and a control circuit, as described in the embodiment of FIG.
It operates so as to maintain the pressure P of 0 at a predetermined value. Also,
A heater 51 for heating the processing chamber 4 is arranged on the outer periphery of the outer chamber 40, and the temperature T0 of the heater 51 is controlled by the temperature controller as in the embodiment of FIG. The temperature T can be maintained at a predetermined value by the controller. The temperature detector 23 may be added to the inner cylinder 6.

With such a configuration, the temperature of the inner cylinder 49 is maintained at a predetermined value during the plasma etching of the wafer 11, so that the same operation as that of the above-described embodiment can be achieved.
The effect that the metal is not scraped or altered by the plasma is obtained. In addition, since the inner surface of the inner cylinder 49 is constantly updated with a new surface, there is no risk of contamination due to alteration of the inner surface. Further, since the temperature of the inner cylinder 49 is maintained at a predetermined value, stable plasma processing becomes possible. In the parallel plate type etching apparatus, the material of the inner cylinder does not have to be limited to the non-magnetic material.

The present invention can be applied to other devices having different plasma generating mechanisms, and application examples thereof are shown in FIGS.
Shown in.

FIG. 8 shows an example in which the present invention is applied to a magnetron RIE device equipped with a magnet 80. The processing chamber 4 as a vacuum container is provided with a side wall 42 and a sample table 10 on which the wafer 11 is placed, and has a high frequency power supply 48 for supplying high frequency energy to the electrodes of the sample table 10. further,
The reaction gas is supplied to the processing chamber 4 through a connection to a vacuum pump for partially evacuating the processing chamber 4 and a valve-controlled conduit 13.
And a reaction gas supply source.

An inner cylinder 49 made of SiC is formed on the inner side surface of the side wall 42. There is a gap between the side wall 42 and the inner cylinder 49, and the heat transfer gas for temperature control is introduced through the gap between the side wall 42 and the inner cylinder 49. The gas supply system includes a gas source, a pressure control valve, a pressure detector, a pressure command instructing means, and a control circuit, as described in the embodiment of FIG. 1, so as to maintain the pressure P in the gap at a predetermined value. To work. A heater 51 for heating the processing chamber 4 is provided on the outer periphery of the side wall 42.
And the side wall 42 through the heater 51 by the temperature controller 22 as described in the embodiment of FIG.
Is controlled to maintain the temperature T of the inner cylinder 49 at a predetermined value.

With such a structure, the temperature of the inner cylinder 49 is maintained at a predetermined value during the plasma etching of the wafer 11, so that the same operation as that of the above-described embodiment is realized.
Stable plasma processing becomes possible. Furthermore, the effect that the metal is not scraped or altered by the plasma is obtained. In addition, since the inner surface of the inner cylinder 49 is constantly updated with a new surface, there is no risk of contamination due to alteration of the inner surface.

FIG. 9 shows an example in which the present invention is applied to an inductively coupled discharge system of the external energy supply and discharge system and a magnetic field-free type system. The processing chamber 4 includes a silicon plate 90 and a quartz chamber 92. It is surrounded by. 91 is a heated antenna member, and 95 is an upper heater. Also in this embodiment, by maintaining the temperature of the quartz chamber 92 at the predetermined value T during the plasma etching of the wafer 11, stable plasma processing can be performed by the same operation as in the above-described embodiment. Further, since the inner surface of the quartz chamber 92 is constantly updated with a new surface by the plasma, there is no fear of contamination due to alteration of the inner surface.

FIG. 10 shows an example in which the present invention is applied to an inductively coupled discharge method and a magnetic field type apparatus of the external energy supply discharge method. 105 is Belger, 1
10 is an antenna. The processing chamber 4 as a vacuum container,
There is an inner cylinder 112, an outer cylinder 114, and a sample table 10 on which the wafer 11 is placed, and there is a high frequency power supply 48 that supplies high frequency energy to the electrodes of the sample table 10. Further, there is a connection to a vacuum pump for partially evacuating the processing chamber 4 and a reaction gas supply source for supplying the reaction gas to the processing chamber 4 through a valve-controlled conduit. In addition, the heater 116 and the cooling water passage 12 that control the temperature by heating and cooling the outer cylinder 114.
It has 0.

Inner cylinder 112 and outer cylinder 11 made of SiC
There is a gap between the four, and a heat transfer gas for temperature control is introduced via the gas supply system 15 between them. The gas supply system is
As described in the previous embodiment, a gas source, a pressure control valve, a pressure detector, a pressure command indicating means, and a control circuit are provided,
It operates so as to maintain the pressure P in the gap at a predetermined value. Further, the temperature T0 of the outer cylinder 114 is controlled by the temperature controller via the heater 116, and the temperature T of the inner cylinder 112 can be maintained at a predetermined value.

With such a structure, by maintaining the temperature of the inner cylinder 112 at a predetermined value, stable plasma processing can be achieved by the same operation as that of the above-described embodiment.
Furthermore, the effect that the metal is not scraped or altered by the plasma is obtained. Further, since the inner surface of the inner cylinder is constantly updated with a new surface, there is no risk of contamination due to alteration of the inner surface.

FIG. 11 shows an example in which the present invention is applied to an inductively coupled discharge method and a magnetic field type apparatus of the external energy supply discharge method. Reference numeral 120 is an electrode, and 48 is a high frequency power source. The processing chamber 4 as a vacuum container includes a ceramic plate 124, an inner cylinder 122, and a sample table 10 on which the wafer 11 is placed. Further, a heater 166 that controls the temperature by heating and cooling the ceramic plate 124.
And a gas passage 130 for supplying gas to the gap. The gas supply system is provided with a gas source, a pressure control valve, a pressure detector, a pressure command instructing means, and a control circuit, as described in the previous embodiment, so as to maintain the pressure P in the gap at a predetermined value. Operate. In addition, the heater 1
The temperature T0 of the ceramic plate 124 is controlled via 26, and the temperature T of the inner cylinder 122 can be maintained at a predetermined value.

By maintaining the temperature of the inner cylinder 122 at a predetermined value with such a structure, stable plasma processing can be performed by the same operation as that of the above-described embodiment. Furthermore, the effect that the metal is not scraped or altered by the plasma is obtained. Further, since the inner surface of the inner cylinder is constantly updated with a new surface, there is no risk of contamination due to alteration of the inner surface.

As described above, in any of the embodiments described with reference to FIGS. 8 to 11, the material of the inner cylinder is preferably a non-magnetic non-metal material in order to reduce the influence on the magnetic field and the electric field.

The present invention is not limited to the plasma etching process described above, but can be applied to a CVD apparatus or a sputtering apparatus.

Further, it is not limited to the case where the process is stabilized by maintaining the temperature of the inner cylinder at a predetermined value. For example, the temperature of the inner cylinder is intentionally changed at the initial stage of the lot to prevent the process change at the initial stage of the lot. The same can be applied to correction.
That is, the process can be stabilized by improving the temperature controllability of the inner cylinder.

The apparatus described with reference to FIGS. 1 to 11 is used as follows. For example, before starting the apparatus, it is checked whether the temperature of the inner cylinder can be controlled to a desired temperature. First, the inside of the processing chamber 4 is evacuated to a predetermined pressure by operating a vacuum pump. Then the heater is activated. The inner cylinder is heated by the heat generated by the heater. Around this, heat transfer gas is supplied to the gap, and the gas pressure in the gap is adjusted to a predetermined pressure. That is, the heating of the inner cylinder is performed by utilizing the heat conduction of the heat transfer gas supplied to the gap. The temperature of the heated inner cylinder is directly or indirectly detected and controlled to a desired temperature. This confirms that the temperature of the inner cylinder can be controlled to a desired temperature. still,
When the temperature of the inner cylinder cannot be controlled to the desired temperature, the operation of the heater and the supply of the heat transfer gas to the gap are stopped, and the inconvenient portion is checked and restored.

On the other hand, in this case, one wafer is loaded into the processing chamber by the transfer device (not shown). The loaded wafer is transferred from the transfer device to the sample table,
The surface opposite to the surface to be processed is placed on the mounting surface corresponding to the sample mounting surface of the sample table.

In the apparatus described with reference to FIGS. 1 to 11, the sample stage is provided with temperature control means having a cooling function, and C
In a device such as a VD device or a sputtering device that needs to heat a wafer during processing, a temperature control unit having a heating function is additionally provided. Further, the wafer mounted on the sample mounting surface of the sample table is held on the sample table by a mechanical clamping means using a spring force or a load, an electrostatic attraction means, a vacuum attraction means, or the like.

Thereafter, the processing gas is supplied into the processing chamber at a predetermined flow rate. Part of the processing gas supplied into the processing chamber is exhausted to the outside of the processing chamber by the operating vacuum pump, whereby the pressure inside the processing chamber is adjusted to the processing pressure of the wafer.

In this state, the processing gas in the processing chamber is turned into plasma by discharge. The surface to be processed of the wafer mounted on the sample mounting surface of the sample table is processed by the plasma. During the processing, the temperature of the wafer is controlled to a predetermined temperature.

During wafer processing, the temperature of the inner cylinder is continuously or occasionally monitored. The monitor temperature is compared with a preset desired temperature, and the temperature of the inner cylinder is controlled to the desired temperature based on the comparison result. The temperature of the inner cylinder is controlled by adjusting the pressure of the heat transfer gas in the gap between the outer cylinder and the inner cylinder, or by adjusting the heat generated by the heater to adjust the temperature of the outer cylinder. In addition, the pressure adjustment of the heat transfer gas in the gap between the outer cylinder and the inner cylinder is
It is carried out by adjusting the supply amount or pressure of the heat transfer gas supplied to the gap.

Generally, a plurality of wafers are successively processed one by one. In this case, the temperature of the inner cylinder is controlled by a motor during the processing of one wafer until the processing of a plurality of wafers is completed, and then controlled to a desired temperature. For example, if there is a problem in the temperature monitoring of the inner cylinder or if the temperature of the inner cylinder cannot be controlled to a desired temperature, it is determined that the wafer processing characteristics cannot be stably maintained, and the wafer processing is interrupted. . Then, at the time of the interruption, countermeasures for solving the problem are implemented. Then, the processing of a plurality of wafers is resumed.

The inconvenience of the temperature monitoring of the inner cylinder and the inability to control the temperature of the inner cylinder to the desired temperature are notified to the operator by issuing some alarm through the control device. As a result, the operator takes recovery measures and restarts the wafer processing. By monitoring the factors related to the temperature control of the inner cylinder, it is possible to check the history leading up to the interruption of the wafer processing, and it is possible to investigate the cause and implement the recovery measures accurately and early. it can.

The processing chamber is cleaned. The processing is carried out by wiping off the inner surface of the processing chamber such as the surface of the inner cylinder or the surface of the inner component arranged in the processing chamber such as the sample table, or by using the plasma of the cleaning gas. Also,
The processing is performed before the processing of the wafers, during the processing of the plurality of wafers, or after the completion of the processing of the wafers.

When the wiping and cleaning process is performed, it is checked whether or not the temperature of the inner cylinder can be controlled to a desired temperature after the process is completed and before the wafer process is started. Also,
When the cleaning process is performed using plasma, it is checked whether the temperature of the inner cylinder can be controlled to a desired temperature during the process or after the process is completed and before the process of the wafer is started.

Furthermore, a break-in discharge (seasoning) treatment is carried out in the treatment chamber. The processing is performed before the wafer processing starts on that day or after the cleaning processing ends and before the wafer processing starts. In this case, it may be possible to check whether the temperature of the inner cylinder can be controlled to a desired temperature during the break-in discharge process.

In order to stabilize the plasma processing characteristics with time, it is necessary to control the temperature of the inner cylinder to a temperature according to the processing conditions of the wafer. Here, as the processing conditions of the wafer, there are a film quality to be processed, a processing gas type, a discharge condition, a discharge type and the like.

Then, the wafer processing conditions are input to the controller of the processing apparatus by the host controller or the operator. The temperature of the inner cylinder corresponding to the wafer processing conditions is previously input to the control device. In the control device, the temperature of the inner cylinder according to the input wafer processing condition is selected and set as the control temperature. On the other hand, the detected and monitored temperature of the inner cylinder is input to the control device. The detection / monitor temperature is
The temperature of the inner cylinder is controlled to the control temperature based on the result of comparison calculation with the control temperature.

Furthermore, for example, when the wafer has a multilayer film structure, the plasma processing characteristics can be improved by controlling the temperature of the inner cylinder to a temperature according to the film quality of each film, the processing gas species, the discharge conditions, and the like. It can be finely grained and stabilized over time.

When the processing performance of the wafer changes during the one rod processing after the break-in discharge (seasoning) processing, the temperature of the inner cylinder is changed along a desired temperature pattern in order to keep the processing performance constant. And good.

Up to now, the temperature adjustment of the inner cylinder of the chamber has been described, but the same can be applied to the temperature adjustment of the sample table cover installed around the sample table.

FIG. 14 shows a sectional view of an embodiment of the sample stage part to which the present invention is applied. A temperature control liquid circulates in the sample table 10, an insulator is applied to the surface of the sample table held at a desired temperature, and a DC power source for an electrostatic chuck in a state where discharge is generated in the processing chamber. By 54, the sample 11 is attracted to the sample table 10 by electrostatic force. Sample 11 and sample stand 10
A heat transfer gas (for example, He
Gas, etc.) is introduced. A sample table cover (an insulator such as alumina or a resistor such as SiC) is installed around the upper part of the sample table 10 to prevent the release of metals that are a problem when the metal sample table 10 is exposed to plasma. ing. By the way, the temperature of the sample table cover surface 50 rises because ions, radicals, etc. in the plasma collide with it. If the temperature of the sample table cover 50 around the sample fluctuates, the scientific / physical reaction around the sample changes, and there is a drawback that the processing characteristics of the sample change. Therefore, the gas sealing means 51 (for example, 0 ring) is provided between the sample table 10 and the sample table cover 51, and the heat transfer gas is introduced between them. The pressure control and the like are the same as in the case of the inner cylinder. In FIG. 14, the heat transfer gas for cooling the sample and the heat transfer gas for cooling the sample stand cover are used together, but it goes without saying that they may be supplied separately.

[0077]

According to the present invention, it is possible to control the temperature of the inner cylinder which is in direct contact with plasma, and it is possible to control the characteristic change of the plasma processing with time. In addition, the non-magnetic and conductive metal material that constitutes the processing chamber is prevented from being scraped or altered by plasma to become a source of heavy metal contamination, and the wall of the processing chamber is a reaction gas used in the processing chamber. As a result, it is possible to provide a plasma processing apparatus and method that have stable plasma processing characteristics without the risk of chemical corrosion.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional front view of a part of a microwave plasma processing apparatus according to an embodiment of the present invention.

FIG. 2 is an enlarged view of an essential part showing a temperature control unit of the inner cylinder of FIG.

3 is a diagram showing functions of the temperature controller of FIG. 1. FIG.

FIG. 4 is a diagram showing a relationship between a pressure P in a gap and a temperature difference in temperature control.

FIG. 5 is a vertical sectional view of a microwave plasma processing apparatus according to a second embodiment of the present invention.

6 is a cross-sectional view of the main parts of the plasma processing apparatus of FIG.

FIG. 7 is a vertical sectional view of a parallel plate plasma etching apparatus according to a third embodiment of the present invention.

FIG. 8 is a vertical cross-sectional view of an example in which the present invention is applied to a magnetron RIE device.

FIG. 9 is a vertical cross-sectional view of an example in which the present invention is applied to an inductively coupled discharge method and a magnetic field-free type apparatus of an external energy supply discharge method.

FIG. 10 is a vertical cross-sectional view of an example in which the present invention is applied to an inductively coupled discharge system of the external energy supply discharge system and a magnetic field type device.

FIG. 11 is a vertical cross-sectional view of an example in which the present invention is applied to an inductively coupled discharge system of the external energy supply discharge system and a magnetic field type device.

FIG. 12 is a vertical cross-sectional view of an oxide film sample with resist as an example of a sample processed by the apparatus of the present invention.

FIG. 13 is a diagram showing the relationship between the number of processed wafers and the temperature of the inner cylinder.

FIG. 14 is a cross-sectional view of an embodiment of a sample table cover section of a processing apparatus to which the present invention is applied.

[Explanation of symbols]

1 ... Magnetron, 2 ... Waveguide, 3 ... Quartz plate, 4 ... Processing chamber, 5 ... Outer cylinder, 6 ... Inner cylinder, 7 ... First solenoid coil, 8 ... Second solenoid coil, 9 ... Vacuum chamber 10, ...
Sample stage, 11 ... Wafer, 13 ... Processing gas supply system, 14 ...
Gap, 15 ... Gas supply system, 17 ... Pressure control valve, 18 ... Pressure detector, 20 ... Control circuit, 21 ... Heater, 22 ... Temperature controller 22

Front page continued (72) Inventor Ryoji Hamasaki 794, Higashi-Toyoi, Daimo, Shimomatsu, Yamaguchi Prefecture Inside the Kasado Plant, Hitachi, Ltd. In the factory (56) Reference JP-A-6-188220 (JP, A) JP-A-4-214873 (JP, A) JP-A-1-220447 (JP, A) JP-A-6-224153 (JP, A) ) JP-A-4-87329 (JP, A) JP-A-7-22404 (JP, A) JP-A-4-184924 (JP, A) JP-A-5-211125 (JP, A) JP-A-62-1 95828 (JP, A) JP 58-153332 (JP, A) JP 63-5526 (JP, A) JP 57-23228 (JP, A) Actual development 63-75034 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 21/3065 B01J 19/08 H05H 1/46 C23C 16/44

Claims (14)

(57) [Claims] 1. A plasma generator, a processing chamber capable of depressurizing, a processing gas supply device for supplying gas to the processing chamber, a sample stage for holding a sample, and a vacuum exhaust device, and the processing chamber is depressurized. In a plasma processing method of plasma-treating a sample by a plasma processing apparatus having an outer cylinder that withstands the above and an inner cylinder arranged inside the outer cylinder, the inner cylinder is made of a non-magnetic material and is configured to be replaceable. The temperature of the inner cylinder is monitored, the desired inner cylinder temperature pre-input according to the processing condition of the sample and the monitor temperature of the inner cylinder are compared and calculated, and the temperature of the outer cylinder is calculated based on the calculation result. A plasma processing method, wherein the inner cylinder temperature is controlled to a predetermined value by controlling. 2. A plasma generator, a processing chamber capable of depressurizing, a processing gas supply device for supplying gas to the processing chamber, a sample stage for holding a sample, and a vacuum exhaust device, and the processing chamber is depressurized. In a plasma processing method of plasma-treating a sample by a plasma processing apparatus having an outer cylinder that withstands the above and an inner cylinder arranged inside the outer cylinder, the inner cylinder is made of a non-magnetic material and is configured to be replaceable. The temperature of the inner cylinder is monitored, and when the sample having the multilayer structure is processed, the desired inner cylinder temperature and the inner temperature which are preliminarily input according to the film quality of each film of the multilayer structure, the processing gas species, and the discharge condition are input. A plasma processing method, comprising performing a comparison calculation with a monitor temperature of a cylinder, and controlling the temperature of the outer cylinder based on the calculation result to control the temperature of the inner cylinder to a predetermined value. 3. A plasma generator, a processing chamber capable of decompressing, a processing gas supply device for supplying gas to the processing chamber, a sample stage for holding a sample, and a vacuum exhaust device, and the processing chamber is decompressed. In a plasma processing method of plasma-treating a sample by a plasma processing apparatus having an outer cylinder that withstands the above and an inner cylinder arranged inside the outer cylinder, the inner cylinder is made of a non-magnetic material and is configured to be replaceable. The temperature of the inner cylinder is monitored, the desired inner cylinder temperature pre-input according to the processing conditions of the lot and the monitor temperature of the inner cylinder are compared and calculated, and the temperature of the outer cylinder is controlled based on the calculation result. By doing so, the inner cylinder temperature is changed at the beginning of the lot to correct the process change at the beginning of the lot. 4. A plasma generator, a processing chamber capable of depressurizing, a processing gas supply device for supplying gas to the processing chamber, a sample stage for holding a sample, and a vacuum exhaust device, and the processing chamber is depressurized. In a plasma processing method of plasma-treating a sample by a plasma processing apparatus having an outer cylinder that withstands and an inner cylinder arranged inside the outer cylinder, the inner cylinder is made of a non-magnetic material and is configured to be replaceable. The temperature of the inner cylinder is monitored, the desired inner cylinder temperature pattern previously input according to the processing conditions of the lot and the monitored temperature of the inner cylinder are compared and calculated, and the temperature of the outer cylinder is calculated based on the calculation result. A plasma processing method characterized by controlling the inner cylinder temperature during one lot processing to control the processing performance of the sample during the one lot processing by controlling. 5. The plasma processing method according to any one of claims 1 to 4, wherein heat of the outer cylinder is transferred via heat transfer gas supplied to a gap between the outer cylinder and the inner cylinder. A plasma processing method, wherein the temperature of the inner cylinder is controlled by transmitting the temperature to the inner cylinder. 6. The plasma processing method according to claim 5, wherein the temperature of the inner cylinder is monitored continuously or at any time. 7. A plasma processing method according to claim 5, when the plurality of samples are processed sequentially for each one, one the temperature of the inner tube until the processing of the plurality of samples is completed A plasma processing method characterized by continuously monitoring each time. 8. The plasma processing method according to claim 5, wherein the history of the sample until the plasma processing is interrupted is checked, and the sample processing is restarted. 9. The plasma processing method according to claim 5, wherein when performing a break-in discharge (seasoning) process in the processing chamber, the temperature of the inner cylinder is monitored during the break-in discharge process. Method. 10. The plasma processing method according to claim 5, wherein the temperature of the inner cylinder is monitored before starting the plasma processing of the sample or after finishing the cleaning processing. 11. The plasma processing method according to claim 5, wherein the plasma processing of the sample is interrupted according to the monitoring result. 12. The plasma processing method according to claim 1, wherein an alarm is issued according to the monitor temperature. 13. A plasma generator, a processing chamber capable of reducing pressure, a processing gas supply device for supplying gas to the processing chamber, a sample stage for holding a sample, a control method, and a vacuum exhaust device, and In the plasma processing method, wherein the processing chamber includes an outer cylinder that withstands a reduced pressure and an inner cylinder disposed inside the outer cylinder, the inner cylinder is made of a non-magnetic material and is configured to be replaceable. Before the treatment, during the plasma treatment of a plurality of samples, or after the plasma treatment of the samples, the cleaning treatment is performed using the plasma of the cleaning gas, and after the cleaning treatment and before the plasma treatment of the samples is started, the inner cylinder Is monitored, and the temperature of the outer cylinder is controlled based on the monitoring result to control the temperature of the inner cylinder to a predetermined value. 14. The plasma processing method according to claim 13, wherein the heat of the outer cylinder is transferred to the inner cylinder via the heat transfer gas supplied to the gap between the outer cylinder and the inner cylinder. A plasma processing method comprising controlling the temperature of the inner cylinder.