JP2001244243A - Plasma treatment equipment and plasma treatment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide plasma treatment equipment wherein plasma treatment in a region corresponding to a pin hole for a lifter pin and a peripheral region of the above region becomes almost uniform in the case that base substance of an object is dielectrics. SOLUTION: Plasma treatment equipment 10 is provided with a hermetic sealed vessel 20, a lower electrode 50 arranged in the hermetic vessel 20 with a member 90 mounted, an upper electrode 40 which faces the lower electrode 50 in the hermetic vessel 20, and a lifter pin 60 to penetrate a through hole 52 arranged on the lower electrode 50 and formed so as to be able to push up the member 90 from the lower electrode 50. The lifter pin 60 is formed of conductive material, at the same potential as the lower electrode, and made to abut against the member 90 mounted on the lower electrode 50 with elasticity by function of an elastic member at least while a plasma is generated. The lifter pin 60 has a covering part formed of material softer than its tip region to cover the tip region.

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 capable of uniformly processing an object having an insulating substrate.

[0002]

2. Description of the Related Art In a plasma processing apparatus, for example, a dry etching apparatus used for manufacturing a semiconductor, a semiconductor wafer is generally used as an object to be processed, and the semiconductor wafer is mounted on a lower electrode. Dry etching is performed by being exposed to plasma while being placed and fixed. When the semiconductor wafer is placed on the lower electrode prior to the dry etching, first, the semiconductor wafer whose lower surface peripheral portion is supported by the workpiece holding portion of the transport mechanism is transported above the lower electrode. . And
The lifter pins protrude from the lower electrode toward the vicinity of the center of the object to be processed through the pin holes formed in the lower electrode. In this state, the object to be processed holding portion of the transport mechanism is lowered to lifter pins. The semiconductor wafer is delivered. Thereafter, the object holding part of the transport mechanism is moved outside the plasma processing apparatus. Then, the lifter pin projecting from the pin hole is retracted and retracted from the lower electrode. As a result, the object to be processed is placed on the lower electrode, and then the plasma processing is performed.

[0003] During the plasma processing, a voltage is applied between the lower electrode and the upper electrode, and the semiconductor wafer mounted on the lower electrode has substantially the same potential as the lower electrode. Plasma is collected on a semiconductor wafer and plasma processing is performed. Therefore, the region of the semiconductor wafer corresponding to the above-described pin hole has a potential slightly different from that of the lower electrode, and the etching in that region may proceed at a different speed from the surrounding region. However, since an object to be processed in semiconductor manufacturing is generally a semiconductor wafer having a high electrical conductivity, even in a region corresponding to the pin hole in the object to be processed, the potential becomes substantially the same as the surrounding region, and the etching speed is also low. It is almost equal.

However, when the substrate of the object to be processed is formed of a non-conductive material such as glass, for example, when the glass substrate used for the liquid crystal panel is the substrate of the object to be processed, it corresponds to the pin hole. In some cases, a potential difference is generated between the region and the surrounding region, and the etching speed may be significantly different. As described above, when the substrate of the object to be processed is a non-conductor, the uniformity of the plasma processing may be impaired in the region corresponding to the pin hole and the region around the pin hole.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and has as its object to provide an area corresponding to a pin hole for a lifter pin even when a substrate of a processing object is a non-conductor. It is an object of the present invention to provide a plasma processing apparatus and a plasma processing method in which plasma processing is substantially uniform between a plasma processing apparatus and a surrounding area.

[0006]

Means for Solving the Problems (1) A plasma processing apparatus according to the present invention comprises an airtight container, a plasma source arranged in the airtight container, and a plasma source arranged in the airtight container,
A lower electrode on which the object is placed; an upper electrode facing the lower electrode in the hermetic container; and a through-hole provided in the lower electrode, which pushes up the object from the lower electrode. And a lifter pin made of a conductive material, wherein the lifter pin is placed on the lower electrode while plasma is being generated from at least the plasma generation source. In contact with the object to be processed.

According to the present invention, while the object is placed on the lower electrode and subjected to the plasma processing, the lifter pins located in the through holes of the lower electrode are in contact with the object. Therefore, the lifter pin having the same potential as the lower electrode contacts the object even in the portion where the through hole of the lower electrode is located, so that the electric potential distribution of the object including the region corresponding to the through hole is uniform. Thus, the object can be uniformly plasma-processed.

(2) The plasma processing apparatus according to the present invention is further characterized in that the plasma processing apparatus further comprises an elastic body that elastically contacts the lifter pin to the object to be processed.

According to the present invention, since the lifter pins are brought into contact with the object to be processed by the elasticity of the elastic body, the lifter pins can be reliably brought into contact with the object to be processed. Further, since the lifter pin is pressed against the object by being pressed through the elastic body, an excessive force is applied to the object by using an elastic body having an appropriate elastic constant with an appropriate deformation amount. The object to be processed can be prevented from being damaged or damaged.

(3) The plasma processing apparatus according to the present invention is characterized in that the lifter pin further includes a coating portion made of a material softer than the tip region and covering the tip region.

According to the present invention, since the lifter pins come into contact with the object to be processed through the covering portion formed of a material softer than the tip end region, the object to be processed is damaged, and thus the lifter pin is damaged. The possibility of dusting can be further reduced.

(4) In the plasma processing apparatus according to the present invention, in (3), the covering portion is formed of a resin,
It is characterized in that it is thin enough to cause almost no potential difference between its outer surface and the tip region.

According to the present invention, there is almost no potential difference between the tip region of the lifter pin and the outer surface of the covering portion covering the tip region. Therefore, by bringing the lifter pins into contact with the object through the covering portion, the region corresponding to the through-hole of the lower electrode in the object to be processed is directly connected to the tip region of the lifter pin having the same potential as the lower electrode. In this case, the potential can be set to substantially the same as when the object is brought into contact with the object. Therefore, the potential distribution of the object to be processed including the region corresponding to the through hole can be made substantially uniform, and the object to be processed can be uniformly plasma-processed. In addition, since the lifter pins come into contact with the object to be processed via the covering portion formed of a material softer than the tip region, the possibility of damaging the object to be processed is low.

(5) In the plasma processing apparatus according to the present invention, in (3), the coating portion is formed of a conductive material.

According to the present invention, there is almost no potential difference between the tip region of the lifter pin and the outer surface of the covering portion covering the tip region. Therefore, by bringing the lifter pins into contact with the object through the covering portion, the region corresponding to the through-hole of the lower electrode in the object to be processed is directly connected to the tip region of the lifter pin having the same potential as the lower electrode. In this case, the potential can be set to be the same as that when the object is contacted. In addition, since the lifter pins come into contact with the object to be processed via the covering portion formed of a material softer than the tip region, the possibility of damaging the object to be processed is low.

(6) The plasma processing apparatus according to the present invention further includes a fixing mechanism for fixing the object to be processed to the lower electrode.

According to the present invention, the object to be processed can be securely brought into close contact with the lower electrode by the fixing mechanism, and the object to be processed can have a uniform potential distribution. Further, even when the lifter pin elastically contacts the object to be processed, the object to be processed does not rise from the lower electrode.

(7) A plasma processing method according to the present invention is a method of performing plasma processing on an object to be processed by using the plasma processing apparatus according to claim 1, wherein the lifter pin projects from the lower electrode. A mounting step of mounting the object to be processed thereon, and a fixing step in which the lifter pins are in contact with the object to be processed, and the object to be processed is fixed on the lower electrode; A plasma processing step of performing plasma processing on the object to be processed in a fixed state by the fixing step.

According to the present invention, the lifter pins located in the through-holes of the lower electrode are in contact with the workpiece while the workpiece is fixed on the lower electrode and subjected to plasma processing. Therefore, the lifter pin having the same potential as the lower electrode contacts the object even in the portion where the through hole of the lower electrode is located, so that the electric potential distribution of the object including the region corresponding to the through hole is uniform. Thus, the object can be uniformly plasma-processed.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below more specifically with reference to the drawings.

1. <Structure of Plasma Processing Apparatus> FIG. 1 is a schematic cross-sectional view showing an overall configuration of an etching apparatus 10 as a plasma processing apparatus in the present embodiment. As shown in this figure, the etching apparatus 10 includes an airtight container 20, a high-frequency power supply 30, an upper electrode 40, a lower electrode 50, and a lifter pin 60.

The shape and material of the hermetic container 20 are not particularly limited. For example, the hermetic container 20 has a cylindrical shape, and is made of anodized aluminum, and has a plasma generating source 30, an upper electrode 40, and a lower electrode. 50 is housed inside. The hermetic container 20 can be opened and closed by an opening / closing mechanism (not shown) such as a gate valve mechanism, and is closed when the opening / closing mechanism is closed. It can be set to about 10 Pa.

The shape and material of the upper electrode 40 are not particularly limited. For example, the upper electrode 40 has a hollow disk shape, is made of aluminum, and the surface thereof is alumite-treated. It can be moved up and down through a connecting rod with a ball screw or the like. The upper electrode 40 has at least one of a reactive gas from a gas supply source (not shown) such as argon, helium, sulfur hexafluoride, carbon tetrafluoride, etc.
One is connected to a reaction gas supply pipe 24 for introducing one. A number of small holes (not shown) are provided on the lower surface of the upper electrode 40, and the reaction gas can flow out of the small holes into the hermetic container 20. The upper electrode 40 has a power of about 500 to 1500 W and a frequency of 300 kHz to 13 M, for example.
It is connected to a high frequency power supply 30 of about Hz. A shield ring 42 made of an insulating material such as tetrafluoroethylene resin is formed on the outer periphery of the upper electrode 40 and the periphery of the lower surface so that plasma is generated in a region having substantially the same size as the object 90 held by the lower electrode 50. Is provided. Note that the upper electrode 40 may be formed of carbon or silicon.

An upper electrode cooling block 48 for cooling the upper electrode 40 is provided in contact with the upper surface of the upper electrode 40. In the upper electrode cooling block 48, a coolant can be circulated from a coolant circulator (not shown) via a coolant pipe 49.

The lower electrode 50 has a disk shape, is made of aluminum, has an alumite-treated surface, is disposed below the airtight container 20, and is electrically grounded. The lower electrode 50 is an object to be processed 90 (for example, a glass substrate)
The mounting surface, that is, the upper surface, is formed somewhat convex. An object held and carried in the object holder of the transport mechanism (not shown) is a lower electrode 5
0. The lower electrode 5
In the vicinity of the center of 0, a through-hole 52 for penetrating a lifter pin 60 that pushes up the object to be processed is provided.
Further, on an upper outer periphery of the lower electrode 50, a clamp ring 80 for fixing the peripheral edge of the mounted object 90 to the lower electrode 50 with a desired clamp load is provided with a ring elevating mechanism 82 via a connecting rod 81, such as an air cylinder. It is installed so that it can go up and down. The clamp ring 80 is made of aluminum and the surface is anodized. The fixing mechanism for fixing the object to be processed includes the above-described clamp ring 80, the connecting rod 81, and the ring elevating mechanism 82.

A lower electrode cooling block 56 is provided below the airtight container 20 in contact with the lower surface of the lower electrode 50. In the lower electrode cooling block 56, a cooling liquid, such as water, can be circulated from a cooling liquid circulator (not shown) via a cooling pipe 57.

In the etching apparatus 10 as the plasma processing apparatus of the present embodiment, the reaction gas supply pipe 24
The upper electrode 40 connected to the high-frequency power source 30 and the grounded lower electrode 50 form a plasma generating portion, and plasma is generated in a space between the upper electrode 40 and the lower electrode 50.

Three or four lifter pins 60 are provided, and are formed so as to be able to push up the workpiece 90 through the through holes 52 provided in the lower electrode 50. Specifically, the lifter pin 60 is connected to a pin elevating mechanism 62, for example, an air cylinder or the like, via a connecting portion 66. The lifter pin 60 is formed by covering the main body 63 with a covering portion 64 having a bottomless hollow cylindrical shape as shown in FIG. The main body 63 of the lifter pin 60 is made of a conductive material such as stainless steel, and has the same potential as the lower electrode 50. The covering portion 64 of the lifter pin 60 is softer than the main body portion, and is a resin having a thickness of 10 μm to 100 μm, more preferably a resin having a thickness of 20 μm to 70 μm, for example, a polyimide resin, a fluorine resin, or a silicon resin, or an organic resin. It is formed of the resin in which an inorganic pigment is dispersed. As shown in FIG. 1, the lifter pin 60 holds the lower electrode 5 at least while plasma is being generated from the plasma generation source, that is, while plasma processing is being performed.
In this state, the object 90 is in contact with the lower surface of the object 90 placed on the upper surface of the object 90. The connecting portion 66 for connecting the lifter pin 60 and the pin elevating mechanism 62 incorporates a spring 67 as an elastic body. The lifter pin 60 elastically contacts the workpiece 90 by the action of the spring 67.

As described above, in the etching apparatus 10 which is the plasma processing apparatus according to the present embodiment, since the lifter pins 60 are brought into contact with the processing target 90 by the elasticity of the spring 67, the lifter pins 60 are 90 can be reliably contacted. In addition, the lifter pin 60 is pressed by the pin elevating mechanism 62 via the spring 67, so that the lifter pin 60 is pressed against the processing target 90. Therefore, by using the spring 67 having an appropriate elastic constant with an appropriate amount of deformation, the lifter pin 60 can be pressed against the processing target 90 with an appropriate pressing force. To prevent the workpiece 90 from being damaged or damaged.

The lifter pin 60 is attached to its main body 6.
Since the object 90 comes into contact with the object to be processed 90 via the covering portion 64 formed of a material softer than 3, the possibility of damaging the object to be processed 90 can be further reduced.

Further, as described above, the covering portion 64
Since it is made of resin, it has almost no conductivity, but its thickness is about 10 μm to 100 μm, and the thickness is such that there is almost no potential difference between the outer surface of the covering portion 64 and the tip region of the main body 63. Has become. Therefore, by bringing the lifter pins 60 into contact with the processing target 90 via the covering portion 64, the region corresponding to the through-hole of the lower electrode 50 in the processing target 90 is lifted to the same potential as the lower electrode 50. The potential can be substantially the same as when the tip region of the pin 60 is in direct contact with the workpiece 90. Thereby, even when a substrate having low conductivity, for example, an object to be processed formed of glass or ceramic is used, uniform plasma processing is performed in a region corresponding to the through hole and a region around the through hole. Becomes possible.

In the etching apparatus 10 of this embodiment, the object 90 is fixed to the lower electrode 50 by a fixing mechanism including the clamp ring 80, the connecting rod 81, and the ring lifting mechanism 82. Have been. Therefore, the object to be processed 90 is fixed to the lower electrode 5 by the fixing mechanism.
0 can be reliably brought into close contact with each other, and the object to be processed 90 can have a uniform potential distribution. In addition, the object to be processed 90 does not rise from the lower electrode 50 due to the pressing force of the lifter pin 60 that contacts the object to be processed 90 with elasticity.

2. <Operation of Plasma Processing Apparatus> Next, an operation of the etching apparatus 10 as the plasma processing apparatus of the present embodiment will be described.

First, the lifter pins 60 are made to protrude from the lower electrode 50. Then, the object to be processed 90 is carried into the hermetic container 20 with the lower peripheral edge portion supported by the object to be processed holding portion of the transport mechanism (not shown), and FIG.
As shown in the schematic partial sectional view of FIG.
0.

Thereafter, by operating the pin lifting mechanism 62 to lower the lifter pin 60 and retract the lifter pin 60 from the lower electrode 50, the object 90 is processed as shown in a schematic partial sectional view of FIG. The state is set on the lower electrode 50.

Then, after moving the object holding portion of the transport mechanism to the outside of the airtight container 20, the airtight container 20 is sealed. Thereafter, the ring elevating mechanism 82 is operated to lower the clamp ring 80, and the object to be processed 90 is pressed against the lower electrode 50. After that, the lifter pin 60 is slightly lifted again by the pin lifting mechanism 62, and the lifter pin 60 comes into contact with the object 90 with an appropriate pressing force as shown in a schematic partial cross-sectional view in FIG. State.

The interior of the airtight container 20 is evacuated to a predetermined degree of vacuum, for example, about several Pa to several tens Pa by a vacuum pump (not shown). Further, the upper electrode 40 connected by the connecting rod 45 is lowered by the operation of the electrode lifting mechanism 44,
The electrode interval with the lower electrode 50 is set to an appropriate interval, for example, about several mm.

Next, a reaction gas such as argon, helium, sulfur hexafluoride, carbon tetrafluoride or the like is supplied from a gas supply source (not shown) to the upper electrode 40 via the reaction gas supply pipe 24. This reaction gas flows out of the small hole (not shown) on the lower surface of the upper electrode 40 into the airtight container 20. At the same time, a high-frequency voltage is applied to the upper electrode 40 by the high-frequency power source 30 and the grounded lower electrode 50
A plasma is generated in the space between. The processing target 90 on the lower electrode 50 is etched by this plasma.

When the etching is completed, the process opposite to that described above is performed, that is, the clamp ring 80 is raised to release the pressure-bonding between the processing target 90 and the lower electrode 50, and the lifter pins 60 are raised to lift the processing target 90. The object 90 is received from below by the object holding portion of the transport mechanism and held there, and is held in the airtight container 2.
Taken from 0.

3. <Modification> 3.1 In the above, the high frequency power supply 3
0 is connected and the lower electrode 50 is grounded. However, the applied potential may be reversed, the upper electrode 40 may be grounded, and the high frequency power supply 30 may be connected to the lower electrode 50. Also in this case, the lower electrode 50 and the lifter pin 60 have the same potential.

3.2 In the above, the lifter pin 6
0 is a covering portion 64 in which the tip region of the main body 63 is made of resin.
An example formed by coating was shown. However, as long as the lower surface of the object to be processed can be brought into contact without damaging it, the lifter pin may be formed only of the main body. Even when this lifter pin is used, the lifter pin having the same potential as the lower electrode comes into contact with the object to be processed even in the portion where the through hole of the lower electrode is located. In addition, the potential distribution of the object to be processed becomes uniform, and the object to be processed can be uniformly plasma-processed.

3.3 In the above, the example of the lifter pin 60 formed by covering the main body 63 with the covering portion 64 having a bottomless hollow cylindrical shape has been described. However, as shown in FIG. 4, a lifter having a covering portion 97 in which a resin film 98, for example, a polyimide resin or fluororesin film having a thickness of about 25 μm is adhered to an end of a main body 96 with an adhesive 99 having a thickness of about 10 to 25 μm. The pin 95 may be used. The adhesive is not particularly specified as long as there is no deterioration due to a rise in temperature due to heat transmitted from the processing target 90 or the like. Even when this lifter pin 95 is used, the lifter pin having substantially the same potential as the lower electrode comes into contact with the object to be processed even at the portion where the through-hole of the lower electrode is located. The potential distribution of the object to be processed including the region becomes substantially uniform, and the object to be processed can be subjected to almost uniform plasma processing.

3.4 In the above, an example has been shown in which the lifter pin is formed at the tip of the main body by covering it with a resin that is softer and more insulating than the main body, for example, a polyimide resin. However, the covering portion may be formed of a conductive material that is softer than the main body portion, for example, a resin material or a conductive polymer material in which carbon or metal is dispersed.

3.5 Further, in the above, the example of the plasma etching apparatus has been described as an example of the plasma processing apparatus, but the present invention can be applied to a plasma CVD apparatus, a sputtering apparatus, and an ion implantation apparatus. is there.

3.6 In the above, an example in which plasma is generated between the upper electrode 40 and the lower electrode 50 has been described. However, a plasma processing apparatus may be used in which plasma is generated in a region inside the hermetic container 20 but not between the upper electrode 40 and the lower electrode 50 so as to be collected at the lower electrode 50.

3.7 The present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an etching apparatus according to an embodiment.

FIG. 2 is a longitudinal sectional view showing the vicinity of the tip of a lifter pin used in the etching apparatus of the embodiment.

FIGS. 3A, 3B, and 3C are partial cross-sectional views illustrating the operation of the etching apparatus according to the embodiment;

FIG. 4 is a longitudinal sectional view showing the vicinity of the tip of a lifter pin in a modified example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Etching apparatus 20 Airtight container 40 Upper electrode 50 Lower electrode 52 Through-hole 60 Lifter pin 64 Covering part 67 Spring (elastic body) 90 Object to be processed

Claims (7)

[Claims] 1. An airtight container, a plasma generation source disposed in the airtight container, a lower electrode disposed in the airtight container, and on which an object to be processed is mounted, and a lower electrode in the airtight container An upper electrode facing the lower electrode, and is formed so as to be inserted into a through hole provided in the lower electrode so as to push up the object to be processed from the lower electrode, made of a conductive material, and made to have the same potential as the lower electrode. And a lifter pin, wherein the lifter pin is in contact with the object to be processed placed on the lower electrode at least while plasma is being generated from the plasma generation source. A plasma processing apparatus characterized by the above-mentioned. 2. The plasma processing apparatus according to claim 1, further comprising an elastic body that elastically contacts the lifter pin to the object to be processed. 3. The plasma processing apparatus according to claim 1, wherein the lifter pin further includes a covering portion made of a material softer than a tip region thereof and covering the tip region. 4. The plasma processing apparatus according to claim 3, wherein the covering portion is formed of a resin and is thin enough to cause almost no potential difference between an outer surface thereof and the tip region. 5. The plasma processing apparatus according to claim 3, wherein the covering portion is formed of a conductive material. 6. The plasma processing apparatus according to claim 1, further comprising a fixing mechanism for fixing the object to be processed to the lower electrode. 7. A method of performing plasma processing on an object using the plasma processing apparatus according to claim 1, wherein the object is mounted on the lifter pins protruding from the lower electrode. A mounting step, a fixing step in which the lifter pins are in contact with the object to be processed, and the object to be processed is fixed on the lower electrode; and the object to be processed in a fixed state by the fixing step. A plasma processing step of performing a plasma processing on the plasma processing method.