JPS61208222A - Plasma treatment method and device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a plasma processing method and apparatus.

[Background of the invention]

For example, when etching a semiconductor element substrate (hereinafter referred to as a substrate), which is a sample, using plasma, it is necessary to suppress the non-uniformity of the etching rate caused by the non-uniform distribution of the electric field, that is, the non-uniformity of the etching process. For this purpose, a method is known in which a sample electrode on which a substrate is installed is rotated during the processing period. (lol Komiseki '5" l-5 Trade No. 2 Ko 8
．． ) However, in such a case, it is possible to improve the uniformity of plasma processing by activating the processing gas in the non-uniform processing length within the processing surface of the sample during the processing of the sample using plasma. There is no recognition that

[Purpose of the invention]

It is an object of the present invention to provide a plasma processing method and apparatus capable of improving the uniformity of plasma processing by activating processing gas in non-uniform processing areas within the surface of the sample to be processed during the processing of the sample using plasma. Our goal is to provide the following.

[Summary of the invention]

The present invention provides a processing chamber in which a counter electrode and a sample electrode are disposed facing each other, an exhaust system that depressurizes and exhausts the inside of the processing chamber, and a processing gas discharged toward the sample electrode via the counter electrode. A gas supply system, and a power source for causing discharge between the counter electrode and the sample electrode, and the counter electrode is composed of an electrode plate and an electrode cover, and the electrode plate and the 1! A device configured to be able to rotate the electrode cover relative to the pole cover and to change the release position or release position and release amount of the processing gas by the rotation allows the processing gas to be released during the sample processing using plasma. By changing the release position or release position and release amount with respect to the surface to be processed of the sample, the processing gas can be activated in non-uniform processing areas within the surface to be processed of the sample during the processing of the sample using plasma. ,
This is intended to improve the uniformity of plasma processing.

[Embodiments of the invention]

For example, when a sample having an M film, a polycrystalline Si film, etc. is etched using plasma, the etching rate distribution in the radial direction from the center of the surface of the sample to be processed is As shown by the solid line in Figure 1, the etching rate is thicker at the periphery of the surface to be processed of the sample (the distribution tends to decrease as it approaches the center).

In this state, the inventor conducted an experiment by changing the release position of the processing gas with respect to the surface to be processed of the sample, especially the non-uniform processing area, in this case, other parts other than the periphery of the surface to be processed. did. As a result, for example, if the release position of the processing gas is set to the center of the surface to be processed, where the etching rate is the lowest, the etching rate will be lower in other parts of the surface than the periphery of the surface, as shown by the broken line in Figure 1. It was found that the uniformity of this distribution can be significantly improved. This is because 5) the gas fraction between the processing gas and the reaction product corresponding to the surface to be processed was improved, and the processing gas was activated. This result is
This means that the uniformity of plasma processing can be improved by changing the release status of the processing gas, that is, the release position or release position and release amount of the processing gas, relative to the surface to be processed of the sample during the sample processing period. do. The present invention has been made based on this viewpoint.

An embodiment of the present invention will be described with reference to FIGS. 2 to 9E4.

'@2 In Figure 2, the processing chamber lO includes the electrode plate 21 that constitutes the counter electrode J and the sample mold [! The electrode plate 31 that constitutes the chrysanthemum.

In this case, they are provided internally facing each other in the vertical direction.

In this case, the exhaust thread cutter is composed of a vacuum pump 41, a variable resistance valve stem, and an exhaust pipe pipe. An exhaust nozzle 11 is provided on the bottom wall of the processing chamber 10 . One end of the exhaust pipe 4 is connected to an exhaust nozzle 11, and the other end is connected to a vacuum pump 41. A variable resistance valve is provided in the exhaust pipe 4.

In FIG. 2, the counter electrode is composed of an electrode plate 4, an electrode cover n, and an electrode shaft. The electrode shaft has its lower end protruding into the processing chamber 10, and is rotatably provided on the top wall of the processing chamber 10 in an airtight manner. The processing chamber 10 and the electrode axis n are electrically insulated. In this case, the means for rotating the electrode shaft is composed of a motor, a pinion 51, and a gear 52. The gear 52 is provided outside the processing chamber 10 of the electrode shaft device. A pinion 51 is provided on the motor shaft and meshes with a gear 52. electrode axis,
23 is grounded via a brush ω. The gas supply system π includes a processing gas source 71 and a gas flow rate control device (hereinafter referred to as MF
C) 72 and a gas supply pipe n. One end of the gas supply pipe 73 is connected to a processing gas source n.

The other end of the gas supply pipe n is connected to the electrode shaft via a rotary joint 74. The gas supply pipe n is communicated with a gas supply path S formed on the electrode shaft n. MFC72 is
In this case, eight gas dispersion grooves 6 are provided in a radial direction.
are formed at equal intervals. The gas dispersion groove 5 is open toward the electrode plate 31. By the way, is it for gas dispersion? 1t
The number and spacing of 25 are set based on the number of sample installation locations on the electrode plate 31 and the spacing.

The gas dispersion groove 5 is communicated with the gas supply path. The electrode cover n is for gas dispersion of the electrode plate 31.

It is provided so as to correspond to the surface on which the groove 5 is formed and not to inhibit the rotation of the electrode plate 21. That is, the longitudinal cross-sectional shape of the electrode cover n is concave in this case, and the electrode plate 21
It has a size and shape that can accommodate. A side wall end of the electrode cover 4 is provided on the top wall of the processing chamber IO. In this case, on the bottom wall of the electrode cover n, as shown in FIG.
A large number of gas discharge holes 3 are provided. That is, the electrode plate 21
on a line having a predetermined angle θ with the gas dispersion groove 5, and
A gas discharge hole 3 is provided so as to correspond to the sample installation position of the electrode plate. The range in which the gas release holes 3 are drilled is, for example, the non-uniform processing area of the surface to be processed of the sample (material) (if the sample is M or Po1y-8t, 2/2 from the peripheral edge).
The peripheral part of 4 is made to correspond to the (part).

In FIG. 2, the sample electrode □□□ is composed of an electrode plate 31 and an electrode axis n. The electrode shaft & is provided with its upper end protruding into the processing chamber 10 and held airtight on the bottom wall of the processing chamber IO. The processing chamber 10 and the 1s polar axis are electrically insulated. The axis of the electrode shaft, C., is aligned with the axis of the electrode shaft. The electrode plate 31 is provided at the upper end of the electrode shaft 32 with the sample installation surface facing upward. The size of the electrode plates 31 is such that, in this case, eight electrode plates can be placed simultaneously between samples on the same circumference.

In FIG. 2, a source, for example a high frequency power source, is
It is installed outside. The lower end of the electrode shaft n is connected to the high frequency power source. The high frequency power source is grounded.

In Figures 2 to 4, a sample 8 is inserted into the processing chamber 0 from the outside.
0 is carried in and placed on the sample installation position of the electrode plate 31 with the surface to be treated facing upward. On the other hand, the inside of the processing chamber 10 is evacuated to a predetermined pressure by the operation of the vacuum pump 41. Thereafter, the processing gas whose flow rate is controlled by the MFC72 is passed through the opposed type tf! (9) to the sample type fF!30. Along with this, a part of this released processing gas is
The inside of the processing chamber 10, which is evacuated by the vacuum pump 41, is adjusted to a predetermined processing pressure by the action of the variable resistance valve 42.

Thereafter, a high frequency voltage is applied to the electrode plate m via the electrode axis n from a high frequency type N90. As a result, the electrode plate 2
Glow discharge occurs between the electrode plate 1 and the electrode plate 31, and the processing gas is turned into plasma.

Using this plasma, the surface of the sample (material) to be processed is subjected to a predetermined process, in this case an etching process. By operating the motor during this processing period, the electrode plate 21 is rotated in the direction of arrow 100. Due to this rotation, the processing gas that has passed through the gas supply path and been dispersed in the gas dispersion groove 3 is released from the gas release hole whose release position changes sequentially from the person in the direction of B (Fig. J4). become. This causes the above-mentioned phenomenon, and as a result, the uniformity of the kneeling process is improved. When the etching process is completed, the electrode plate is rotated 40 times, and the supply of the gas and the application of the high frequency voltage are stopped, and then the processed sample is
It is removed from the electrode plate A and carried out to the outside of the processing chamber 10.

In this embodiment, the following effects can be obtained.

(1) During the etching process of the sample, it is possible to activate the processing gas in non-uniform areas on the surface of the sample to be processed, so that the etching rate is uniform at each position on the surface of the sample to be processed. The uniformity of the etching process is improved.

(2) The average kneeching speed within the surface of the sample to be processed is improved, for example, as shown by the broken line in Figure 1!1, and the throughput is improved.

FIG. 5 shows a second embodiment of the present invention, and is largely different from FIG. 2 which shows the above embodiment of the present invention. The point is that the electrode cover n' is rotatable.

In FIG. 5, the electrode cover n' has a portion that substantially includes the electrode plate 21' therein, and a portion that includes the lower end of the electrode shaft n. In this case, the electrode shaft is fixed to the top wall of the processing chamber 10. The electrode cover includes the electrode plate 21' and the lower end of the electrode shaft, and is rotatably provided on the electrode shaft 3 while keeping the inside of the processing chamber 10 airtight. The gear 52 is provided on the electrode cover n' outside the processing chamber 10. Also, 1
! A recess that forms the bottom wall of the electrode force bar and the gas dispersion chamber n is formed on the surface of the electrode plate 21' that corresponds to the bottom wall of the electrode cover n'. The gas distribution chamber n is communicated with the gas supply path U. Further, the other end of the gas supply pipe 73 communicates with the gas supply path U and is connected to the electrode shaft 23t, and the electrode shaft n is grounded. Note that in FIG. 5, other devices that are the same as those in FIG. 2 and FIG.

In this embodiment, it is possible to obtain the same effect as in the above-mentioned embodiment, and furthermore, since the release position of the processing gas also changes in the circumferential direction when viewed from the surface to be processed of the sample, the knee y9
- The uniformity of the processing is improved.

Figure @6 shows the embodiment of $3 of the present invention, and differs from Fig. 4 which shows the above-mentioned embodiment of the present invention in that the gas discharge holes formed in the electrode cover n are A, B: The hole diameter at the center is larger than the hole diameter at both ends.

In this example, it is possible to obtain the same effect as in the above-mentioned example, and furthermore, since not only the gas release position but also the gas release amount can be changed, the etching rate at the center of the surface to be processed of the sample can be changed. If it is even smaller, it is more effective.゛ Fig. 7 shows a fourth embodiment of the present invention, and the difference from Fig. 4 showing the above-mentioned embodiment of the present invention is that the electrode cover n has gas release grooves Z instead of gas release holes. This is the point where it is formed. In addition, in this case, the groove width of the gas release groove Z is A
, B It is narrow at both ends and wide at the center.

In this embodiment, the same effects as those in the third embodiment can be obtained.

@8 Figure shows the fifth embodiment of the present invention.

The difference from FIG. 4, which shows the above embodiment of the present invention, is that the gas discharge hole formed in the electrode cover 4 is located in the center between A and B. It is a point that is perforated around the .

In this embodiment, the same effects as those in the third embodiment can be obtained.

FIG. 9 shows a sixth embodiment of the present invention, and differs from FIG. 3 showing the above-mentioned embodiment of the present invention in that the electrode plate 31 between the sample electrodes at the electrode base of the counter electrode head is A gas dispersion groove 3' is spirally formed on the surface facing the . One end of the gas dispersion groove 5', and in the second case, the end on the center side of the electrode root gyre, are communicated with the gas supply path.

In this embodiment, the same effects as those in the above embodiment can be obtained.

In the third to fifth embodiments described above, the electrode cover is fixed at the opposing electrode and the electrode plate is rotated. The electrode cover may be rotated while being fixed.

〔Effect of the invention〕

As explained above, the present invention can activate the processing gas in non-uniform processing areas within the surface of the sample to be processed during the sample processing using plasma, thereby improving the uniformity of plasma processing. There is an effect that it can be done.

[Brief explanation of the drawing]

Figure @i is a schematic diagram of the relationship between the gas release position and etching rate, Figure 2 is a vertical sectional view of the main part showing an example of a plasma processing apparatus in which the present invention is implemented, and Figure @3 is the opposite of Figure $2. The plan view of the electrode plate of the electrode, FIG. 4, is the same (the plan view of the electrode cover, FIG.
FIGS. 6 to 8 are longitudinal cross-sectional views of main parts showing examples of the present invention, and FIGS. The figure shows a sixth example of a plasma processing apparatus embodying the present invention, and is a plan view of an electrode plate of a counter electrode. 10...Processing chamber, 20.20'...Counter electrode, 21.21'...Electrode plate, 22. Z2'・
...Electrode cover, 25.25'...Gas dispersion groove, 26...Gas release hole, 2'...
...Other gas release holes, n...Gas dispersion chamber, nephew...
...Gas release groove, (capital) ...Sample electrode,
Off: Exhaust system, Father: Motor, 51.
...Gear, 70...Gas supply system, ■...
・・・High frequency power supply 11 Figure N J1's sho (9 Ko side jilt included, t et al distance 2nd mouth 3 Figure 4 5th arrow 6 Concave off Figure 18 Figure O 9

Claims (1)

[Claims] 1. A plasma processing method characterized by changing the release position or the release position and release amount of a processing gas with respect to the surface to be processed of the sample during a sample processing period using plasma. . 2. A processing chamber in which a counter electrode and a sample electrode are disposed facing each other, an exhaust system for evacuating the inside of the processing chamber under reduced pressure, and supplying a processing gas discharged toward the sample electrode via the counter electrode. The counter electrode includes a gas supply system and a power source that generates a discharge between the counter electrode and the sample electrode, the counter electrode is configured with an electrode plate and an electrode cover, and the electrode plate and the electrode cover are arranged relative to each other. 1. A plasma processing apparatus, characterized in that the plasma processing apparatus is configured to be rotatable, and to be able to change the release position or the release position and release amount of the processing gas by said rotation.