WO2003030235A1

WO2003030235A1 - Plasma processor and plasma processing method

Info

Publication number: WO2003030235A1
Application number: PCT/JP2002/008968
Authority: WO
Inventors: Yoshiyuki Kobayashi; Keiichi Nagakubo
Original assignee: Tokyo Electron Limited
Priority date: 2001-09-27
Filing date: 2002-09-04
Publication date: 2003-04-10
Also published as: JP2003100709A; JP4860078B2

Abstract

While a wafer (W) mounted on a lower electrode (2) is etched as predetermined, the top of a lifter pin (60) electrically connected to the lower electrode (2) remains pressed on the wafer (W) by a spring built in the lifter pin (60). Most part of the rear of the wafer (W) corresponding to a through hole (2a) receives the contact of the top of this lifter pin (60) to keep a condition similar to a contact with the lower electrode (2). Thus, the whole of a substrate to be processed is processed uniformly, so that the uniformity of the in-plane processing of the substrate to be processed is more improved than conventional.

Description

Description Plasma processing apparatus and plasma processing method

The present invention relates to a plasma processing apparatus and a plasma processing method, and more particularly to a plasma processing apparatus for performing a plasma processing such as etching on a substrate to be processed such as a semiconductor substrate (semiconductor wafer) or a glass substrate (glass wafer) for a display device. The present invention relates to a processing apparatus and a plasma processing method. Background art

Conventionally, in the field of semiconductor device manufacturing, plasma is generated in a processing chamber, and this plasma is applied to a substrate to be processed (for example, a semiconductor wafer or a glass substrate for a display device) arranged in the processing chamber. A plasma processing apparatus that performs a predetermined process (for example, etching, film formation, and the like) is used.

In such a plasma processing apparatus, a predetermined process is performed by applying plasma to a substrate to be processed in a vacuum chamber whose inside can be hermetically closed. For example, in a so-called parallel plate type plasma processing apparatus, an upper electrode and a lower electrode are provided in the vacuum chamber so as to face in parallel. Then, the substrate to be processed is placed on the lower electrode, high-frequency power is supplied between the upper electrode and the lower electrode to generate plasma, and the plasma is applied to the substrate to be processed to perform a predetermined process. It is configured as follows.

That is, in the above-described plasma processing apparatus, the lower electrode also serves as a support for the substrate to be processed. And for this lower electrode The loading and unloading of substrates to be processed is usually automatically performed by a transport mechanism.

For this reason, the lower electrode penetrates the lower electrode vertically so that the substrate to be processed is placed on the lower electrode and the substrate to be processed placed on the lower electrode can be easily taken out. Thus, a substrate supporting member is provided. And, by moving the substrate support member and the lower electrode relatively up and down, the substrate support member protrudes above the lower electrode, and the substrate to be processed is supported on the lower electrode by the substrate support member; and From this state, the substrate supporting member is retracted into the lower electrode, and the substrate to be processed can be placed on the lower electrode.

In addition, the above-mentioned substrate support member is often formed in a pin shape (elongated rod shape). In many cases, about three or four pin-shaped substrate support members are provided, and the substrate to be processed is supported at three or four points. Further, in order to provide such a substrate support member, three or four through holes are provided in the lower electrode so as to penetrate in the vertical direction. As described above, in the plasma processing apparatus, the lower electrode also serving as a support for the substrate to be processed is provided with a through-hole for providing a pin-shaped substrate support member or the like. During the plasma processing, the substrate support member is retracted into the lower electrode, and the processing is performed while the substrate to be processed is supported on the upper surface of the lower electrode.

However, in the above-described conventional plasma processing apparatus, the substrate to be processed mounted on the lower electrode is in a non-contact state with the lower electrode at the portion of the through hole described above.

For this reason, the processing speed of the through-hole portion is different from that of the other portions, for example, a phenomenon that the etching rate of the through-hole portion is slower than that of the other portions occurs. The problem of loss of uniformity O Disclosure of the invention

SUMMARY OF THE INVENTION An object of the present invention is to provide a plasma processing apparatus capable of performing uniform processing over the entire surface of a substrate to be processed and improving the uniformity of processing within the surface of the substrate to be processed, as compared with the related art. And to provide a plasma processing method.

According to the present invention, there is provided a vacuum chamber which is capable of airtightly closing the inside thereof, performs a predetermined process by applying plasma to a substrate to be processed, and a mounting surface provided in the vacuum chamber and formed on an upper surface. An electrode configured to place the substrate to be processed thereon, and an electrode provided so as to penetrate the electrode, and by moving up and down relatively to the electrode, the back side of the substrate to be processed is moved. A plasma processing apparatus, comprising: a substrate supporting member configured to support and move the substrate to be processed up and down between the mounting surface and the mounting surface. The apparatus is characterized in that it is electrically connected and that the substrate support member is kept in contact with the back surface of the substrate to be processed during the processing of the substrate to be processed.

Further, the present invention is characterized in that in the above-mentioned plasma processing apparatus, high-frequency power is supplied to the electrode.

Further, the present invention is characterized in that, in the plasma processing apparatus, the substrate support member is formed in a pin shape and is elastically expandable and contractible. Further, the present invention is characterized in that, in the above-described plasma processing apparatus, four pin-shaped substrate support members are provided on a vertically movable support.

The present invention also provides the plasma processing apparatus, wherein the contact portion of the pin-shaped substrate support member with the back surface of the substrate to be processed is made of a conductive resin. It is characterized by being composed of a material or a protective film.

Further, the present invention is characterized in that, in the plasma processing apparatus, an etching process is performed by applying plasma to the substrate to be processed.

The method of the present invention is characterized in that a predetermined process is performed by applying plasma to the substrate to be processed using the plasma processing apparatus. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a diagram schematically showing a schematic configuration of an embodiment of the plasma processing apparatus of the present invention.

FIG. 2 is a diagram schematically showing an enlarged main part configuration of the plasma processing apparatus of FIG. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 schematically shows an outline of a configuration of an embodiment in which the present invention is applied to a plasma etching apparatus for etching a wafer. In the figure, reference numeral 1 denotes a vacuum chamber which is made of, for example, aluminum or the like and is configured so as to be able to hermetically close the inside thereof, and forms a cylindrical plasma processing chamber.

A shield box 10 is provided above the vacuum chamber 1. A drive mechanism 20 for moving a lower electrode 2 described later up and down is provided below the vacuum chamber 1.

Inside the vacuum chamber 1, there is provided a lower electrode 2 for supporting a wafer W as a substrate to be processed substantially horizontally with the surface to be processed facing upward. Then, in the vacuum chamber 1 so as to face the lower electrode 2 in parallel. An upper electrode 3 is provided on the ceiling.

The upper electrode 3 is formed with a large number of through holes (not shown) to form a so-called short head. A predetermined processing gas supplied from a processing gas supply source (not shown) can be uniformly delivered from these through holes toward the wafer W provided on the lower electrode 2. On the other hand, an exhaust port (not shown) is provided at the bottom of the vacuum chamber 1 so that the inside of the vacuum chamber 1 can be exhausted to a predetermined degree of vacuum by an exhaust mechanism such as a vacuum pump (not shown).

The upper electrode 3 is electrically connected to a high-frequency power supply 22 via a matching box 21 so that the upper electrode 3 has a predetermined frequency (for example, 380 kHz to 100 MHz). It is configured to be able to supply high frequency power.

Also, a ring-shaped clamp ring 4 supported from the ceiling side of the vacuum chamber 1 is provided between the lower electrode 2 and the upper electrode 3. The clamp ring 4 is configured to be vertically movable by a clamp ring drive mechanism 4a. The clamping ring 4 and the clamp ring driving mechanism 4 a press the peripheral portion of the wafer W toward the lower electrode 2, and fix the wafer W on the lower electrode 2.

In addition, a coolant flow path (not shown) for circulating a coolant is provided to the lower electrode 2, and He gas is supplied to the back surface of the wafer W in order to efficiently transmit cold heat from the coolant to the wafer W. A gas introduction mechanism (not shown) is provided to control the temperature of the wafer W to a desired temperature. Further, a resin film (not shown) is provided on the upper surface of the lower electrode 2 (the mounting surface of the wafer W) so as not to damage the rear surface of the wafer W.

The lower electrode 2 is configured to be vertically movable by the above-described driving mechanism 20 including, for example, a ball screw and a motor for rotating the ball screw. Has been established. A bellows 5 made of stainless steel or the like is provided between the lower electrode 2 and the bottom in the vacuum chamber 1 to hermetically close the space therebetween.

Further, a lifter unit 6 provided with a plurality (four in this example) of lifter pins described later as a substrate support member is provided at the center of the lower electrode 2. Then, as the lower electrode 2 moves up and down, the lifter pin is configured to be able to protrude above the lower electrode 2 through the through hole 2 a provided in the lower electrode 2.

In FIG. 1, reference numeral 7 denotes a high frequency power of a predetermined frequency (for example, 380 kHz to 40.6 MHz) from the high frequency power supply 24 via the matching unit 23, and 2 shows the RF port to supply to 2. Reference numeral 8 denotes a temperature sensor cable for deriving a detection signal from a temperature sensor provided in the lower electrode 2.

Next, the configuration of the above-described rifle unit 6 will be described with reference to FIG. Note that FIG. 2 schematically shows the configuration of the lifter unit 6, and the left side of the dashed line shown in the center of the figure shows the state in which the lifter pin 60 is lowered. The right side of indicates that the lifter pin 60 has been raised.

The lifter pins 60 shown in FIG. 2 are arranged so as to penetrate through holes 2 a provided in the lower electrode 2, and the lower end thereof is fixed to the base 61 by screwing or the like. I have. Usually, about three or four lifter pins 60 are provided. In the present embodiment, four lifter pins 60 are fixed to the base 61, and these lift pins 60 are symmetrically arranged around the center of the lower electrode 2.

A through hole 61 a is provided in the center of the base 61. Then, the support shaft 62 is inserted into the through hole 61a from below, and the upper end of the support shaft 62 is The base 61 is fixed to the lower electrode 2 with screws or the like, and the base 61 is supported by a stopper 63 provided at the lower end of the support shaft 62. Are supported so as to be relatively vertically movable. Further, a lifter spring 64 is provided on the support shaft 62 so that the base 61 is directed downward with respect to the lower electrode 2 (in the direction in which the lift pin 60 descends). ) Is configured to be biased.

At the lower part of the base 61, there are provided a lift shaft 65 and a rod 66, and through these lift shaft 65 and the rod 66, the base is provided. The bottom of 6 1 is pressed, and the base 6 1 moves upward relative to the lower electrode 2 while contracting the lift spring 6 4, and the lift pin 60 protrudes from the upper surface of the lower electrode 2. It is configured to be. The bottom of the base 61 is pressed by the lift shaft 65 and the rod 66 by moving the lower electrode 2 up and down, or by the lift shaft 65 and the rod 66. Is performed by moving up and down.

Further, a spring (coil spring, etc.) (not shown) is built in the lift pin 60, and as shown in the right end of FIG. 2, a predetermined stroke S, for example, about 3 mm, is elastically expandable and contractable. It is configured. Further, a coating film 60a made of a conductive resin, for example, conductive Teflon (registered trademark) is applied to a tip portion of the rifle pin 60, and the coating film 60a is applied through the coating film 60a. The top of the pin 60 is in contact with the back surface of the wafer W. It should be noted that the present invention is not limited to the formation of the coating layer, and a configuration may be adopted in which a conductive resin material is attached to the tip of the pin 60 by bonding or the like.

The rifle pin 60, the base 61, the support shaft 62, the rifle spring 64, and the like are made of a conductive material such as stainless steel. Further, since the coating film 60a is also conductive, (C) The top of the riff pin 60 contacting the rear surface of W is in a state of being electrically connected to the lower electrode 2 and has substantially the same potential as the lower electrode 2. .

The coating film 60a is for preventing the back surface of the wafer W from being scratched. In order to improve the processing uniformity, it is preferable to make the coating film as thin as possible. The thickness is preferably, for example, about 50 5m to 200 / m. Further, it is possible to prevent the back surface of the wafer W from being scratched by machining the tip of the lift pin 60 without providing the coating film 60a.

Then, the lift pins 60 are relatively lowered with respect to the lower electrode 2, and the wafer W mounted on the lower electrode 2 is fixed by the clamp ring 4 described above, and a predetermined etching process is performed on the wafer W. During this operation, the top of the pin 60 is pressed against the back surface of the wafer W by a spring built in the bin 60 as shown on the left side of FIG. (The remaining stroke S 1 of the pin 60 shown in the figure is, for example, about 1 mm). As a result, most of the portion corresponding to the through-hole 2a on the back surface of the wafer W is brought into contact with the top of the pin 60, so that the lower electrode is substantially electrically electrically connected. The state is kept the same as the state of contact with 2.

At this time, each of the four provided lift pins 60 is brought into contact with the back surface of the wafer W by the elastic force of each built-in individual panel. For example, each lifter pin 60 Even if there is a slight deviation in the height of the top (the contact surface with the wafer W), it is possible to ensure that all four pins 60 of each rift are securely in contact with the back surface of the wafer W. .

On the other hand, when loading and unloading the wafer W to and from the lower electrode 2, as shown on the right side of FIG. The wafer W is lifted above the lower electrode 2 by four lifter pins 60 so that the wafer W is supported by the four lifter pins 60. At this time, with the wafer W held, the lift pin 60 hardly shrinks, the lift pin 60 descends to the lowest point, and the tip of the lifter pin 60 is connected to the lower electrode 2. The elastic force of the panel built in each lifter pin 60 is set on the upper surface of the panel so as to protrude by a value obtained by subtracting the stroke S i from the total stroke S (for example, 3 mm).

Next, a plasma etching process in the plasma etching apparatus configured as described above will be described.

First, a gate valve (not shown) is opened, and the wafer W is loaded into the vacuum chamber 1 by a transfer ham of an automatic transfer mechanism or the like via a load lock chamber (not shown) arranged adjacent to the gate valve. . At this time, the lower electrode 2 is lowered to a predetermined position in advance, and the four riff pins 60 are projected on the lower electrode 2. The wafer W is placed. After placing the wafer W, the transfer arm is retracted out of the vacuum chamber 1, and the gate valve is closed.

Thereafter, the lower electrode 2 is raised to a predetermined height by the drive mechanism 20, and accordingly, substantially the entirety of the lift pin 60 is housed in the lower electrode 2. Then, the peripheral edge of the wafer W is pressed against the lower electrode 2 by the clamp ring 4, and the wafer W is fixed on the lower electrode 2. At this time, as shown in the left part of FIG. 2 described above, the top of each lifter pin 60 is in a state of being abutted on the back surface of the wafer W by the spring built in the lifter pin 60. It has been.

After that, the inside of the vacuum chamber 1 is evacuated by the exhaust mechanism, and a predetermined processing gas is introduced into the vacuum chamber 1 through the through hole of the upper electrode 3, for example. For example, it is introduced at a flow rate of 100 to 1 000 sccm, and the inside of the vacuum chamber 1 has a predetermined pressure, for example, 1.33 to: L33Pa (10 to: LOO OmT orr), preferably 2.67 to 26.7. It is kept at about P a (20 to 200 mT orr).

Then, in this state, high-frequency power having a frequency of, for example, 380 KHz to 100 MHz is supplied from the high-frequency power supplies 22 and 24 to the upper electrode 3 and the lower electrode 2, and the processing gas supplied into the vacuum chamber 1 is supplied. The film is turned into plasma, and a predetermined film on the wafer W is etched by the plasma.

At this time, the top of each rifle pin 60 electrically connected to the lower electrode 2 is in contact with the back surface of the wafer W as described above. This suppresses non-uniform processing, such as a decrease in the etching rate at the portion of the through-hole 2 a of the lower electrode 2, and improves in-plane uniformity of the etching processing of the wafer W. be able to.

When the predetermined etching process is performed, the supply of the high-frequency power from the high-frequency power sources 22 and 24 and the supply of the processing gas are stopped, the etching process is stopped, and the procedure is reverse to the procedure described above. Then, the wafer W is carried out of the vacuum chamber 1.

Using the etching apparatus described above, the pressure in the vacuum chamber 1 was 26.7 Pa (200 mTorr), and the processing gas was CHF ₃ (flow rate 45 SCCM) + CF ₄ (flow rate 90 SCCM) + Ar (flow rate 600 SCCM). the high-frequency power as 1 1 00W, PR (photoresist g) in Bruno £ 03 Bruno 3:10 ₂ went 60 seconds etching of the wafer W is formed. As a result, a decrease in the etching rate of the portion of the wafer W corresponding to each of the lift pins 60 (through holes 2a) was suppressed, and the in-plane uniformity of the etching rate of the wafer W was 3.7%. . Also, under the same conditions, each of the ribs 60 was changed to one without a built-in panel. The etching process was performed in the state of being brought into contact with the substrate. As a result, the in-plane uniformity of the etching rate was 5.0%.

For comparison, each lifter pin 60 was etched under the same conditions without contacting the back surface of the wafer W. As a result, the etching rate of the portion of the wafer W corresponding to each rifle pin 60 (through hole 2a) was reduced, and the in-plane uniformity of the etching rate was 13.9%.

As is evident from the above results, during the etching process, the top of the pin 60, which is electrically connected to the lower electrode 2, is brought into contact with the back surface of the wafer W, so that the in-plane etching rate is reduced. The uniformity was greatly improved. In addition, the use of lifter pins 60 with built-in panels ensures that the pins 60 are in contact with the back surface of the wafer W, thereby greatly improving the in-plane uniformity of the etching rate. I was able to.

In the above embodiment, the case where the present invention is applied to the etching apparatus for etching the wafer W has been described, but the present invention is not limited to such a case. For example, it may be one that processes a substrate other than the wafer W, and may be applied to plasma processing other than etching, for example, a film forming apparatus such as a CVD.

Further, in the above embodiment, the case where four lift pins 60 are used as the substrate supporting member has been described. However, the number of lift pins 60 may be any number. However, the present invention is not limited to the pin-shaped substrate supporting member, and a substrate supporting member having another shape may be used.

As described above, according to the present invention, uniform processing can be performed over the entire surface of a substrate to be processed, and the uniformity of processing within the surface of the substrate to be processed can be improved as compared with the related art. Can be. Industrial applicability

INDUSTRIAL APPLICABILITY The plasma processing apparatus and the plasma processing method according to the present invention can be used in a semiconductor manufacturing industry or the like that manufactures semiconductor devices. Therefore, the present invention has industrial applicability.

Claims

The scope of the claims

1. A vacuum chamber for allowing the inside to be hermetically closed and for applying a predetermined process by applying plasma to the substrate to be processed;

An electrode provided in the vacuum chamber and configured to mount the substrate to be processed on a mounting surface formed on an upper surface;

The substrate is provided so as to penetrate the electrode, and moves up and down relatively to the electrode to support the back side of the substrate to be processed, and between the upper side of the mounting surface and the mounting surface. A substrate support member for vertically moving the substrate to be processed, and

The substrate support member is electrically connected to the electrode, and the substrate support member is kept in contact with the back surface of the substrate to be processed during processing of the substrate to be processed. Plasma processing apparatus characterized by comprising

2. The plasma processing apparatus according to claim 1,

A plasma processing apparatus configured to supply high-frequency power to the electrode.

3. The plasma processing apparatus according to claim 1,

A plasma processing apparatus, wherein the substrate support member is formed in a pin shape and is elastically stretchable.

4. The plasma processing apparatus according to claim 3,

4. A plasma processing apparatus, wherein four pin-shaped substrate support members are provided on a vertically movable support.

5. The plasma processing apparatus according to claim 3,

A contact portion of the pin-shaped substrate support member with the back surface of the substrate to be processed is made of a conductive resin material or a protective film. Plasma processing apparatus.

6. The plasma processing apparatus according to claim 1,

A plasma processing apparatus, wherein an etching process is performed by applying plasma to the substrate to be processed.

7. A plasma processing method using the plasma processing apparatus according to claim 1, wherein predetermined processing is performed by applying plasma to the substrate to be processed.