JPH03211725A - 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 [Industrial Application Field] The present invention relates to a plasma processing method and apparatus for samples such as wafers for manufacturing semiconductor devices.

[Conventional technology]

Conventional plasma processing methods and devices include, for example,
JP-A-56-53853 and JP-A-63-2382
No. 88 is mentioned. These examples show a method and apparatus for electrostatically adsorbing a wafer and performing plasma processing (dry etching in this example).

[Problem to be solved by the invention]

Among the conventional examples described above, the former is one in which the wafer is electrostatically attracted via plasma, and the electrostatic adsorption force is generated after the plasma is turned on. Therefore, there is a problem that the thermal resistance between the wafer and the electrode (low temperature source) is large until just before plasma generation, and it takes time to sufficiently lower the wafer temperature, making it impossible to increase the throughput.

Furthermore, in the latter conventional example, an insulating film is provided between the twin FI & and the wafer to perform electrostatic adsorption, and since electrostatic adsorption can be performed without using plasma, the above-mentioned problem can be overcome.

On the other hand, however, since the wafer is polarized positively and negatively to charge up, current flows inside the wafer when discharge occurs, causing a problem of deterioration of the withstand voltage of the thin gate film.

An object of the present invention is to provide a plasma processing method and apparatus that uses a single electrode and that adsorbs a wafer before plasma generation.

[Means to solve the problem]

The above purpose is to provide an insulating film on the nest electrode, ground the top or edge of the installed wafer and electrostatically attract it, remove the ground and perform plasma treatment, and release the attraction force after the plasma treatment. achieved by

[For production]

Since a single electrode is used, it is possible to charge up uniformly over the entire wafer using the same electrode. As a result, no current is generated inside the 7-chip during plasma generation. In addition, since the wafer can be adsorbed before plasma generation, it is easy to cool the wafer until plasma generation.
When gas cooling is used in combination, excellent temperature characteristics can be obtained since discharge can be started after the gas pressure has been sufficiently increased through adsorption.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 shows an overall configuration diagram of a plasma processing apparatus, in this case a microwave etching apparatus, and FIG. 2 is a diagram showing details of the electrode 6 of FIG. 1.

The microwave etching device includes a waveguide 11 discharge tubes 2, l.
iiMh generation coil 3, electric 1fi5, high frequency electric jl16
A high-density plasma is created in the discharge tube 2 by the electric field of the microwave (hereinafter referred to as [μ wave]) 4 introduced into the waveguide 1 and the fii field of the magnetic field generating coil 3. By applying a high frequency voltage to the electrode 5, 1lEW
The configuration is such that reactive ion etching can be performed by applying an appropriate bias voltage to the wafer 6 set above to draw in ions in the plasma.

In FIG. 1, the discharge chamber 2 is configured to be separated from the buffer chamber 7 by a shutter 11, and the discharge chamber 2 is separated from the buffer chamber 7 by a shutter 11.
An arm 8 for wafer transfer is provided inside, and can be rotated and moved up and down by a rotating arm 9 and a vertical mechanism 10. Further, a wafer push-up bottle L is provided inside the electronic 11i@5, and has a vertical mechanism separate from the vertical mechanism 13 of the electronic FIA5.

In FIG. 2, the electrode 5 is surrounded by an insulating weight 5,
A high frequency power source 16 and a DC power source 18 are connected.

17 is a matching circuit, and 4 is a high frequency cutoff circuit.

Further, the upper surface of the electrode 5 is coated with a scar 14.

After the wafer 6 is transported by the arm 8 and is placed on the insulating film 14 of the electrode 5 using the wafer push-up pin,
When the arm 8 is lowered to come into contact with the outer periphery of the wafer 6 and grounded, and the DC voltage i18 is turned on, the wafer 6 is electrostatically attracted to the electrode 5. Thereafter, the arm 8 rises, rotates and escapes, sets the position of the utility pole 5 with the weno 6 adsorbed, starts μ-wave discharge and high-frequency application, and performs etching. If the DC power source is turned on during processing, electrostatic absorption and power saving can be maintained through plasma, but it is also possible to use only a self-bias voltage by applying a high frequency.

When the etching process is finished, the electrode 5 returns to its original position.
The wafer 6 is released from the suction force by contact with the wafer pusher and is carried out by the arm 8.

In the etching process described above, in the present invention, a single electrode is used for electrostatic adsorption, so that the entire wafer can be charged up uniformly with the same polarity, so that no current is generated inside the wafer when plasma is generated. There is no. In addition, since the wafer can be adsorbed before plasma generation, it is easy to cool the wafer until plasma generation.Especially when it is desired to introduce a cooling gas such as He to the underside of the wafer to reduce the thermal resistance between the wafer and the insulating film. Since the discharge can be started after the gas pressure has been sufficiently increased, it is possible to control the temperature of the superior sea urchin, and the cooling time before discharge is shortened (thus increasing the throughput).

As described above, in the present invention, the wafer is grounded during suction by the transfer arm 8, but as shown in FIG.

This may be done using the up-and-down mechanism 10'. In particular, when the buffer 1 chamber 7 is connected to another processing chamber, M(7)
Since the arm 8' that received the wafer in the chamber can return to the wafer 6 in the direct method and ground it, it has the effect of increasing the throughput.

Note that in this embodiment, the arm 8 is used to ground the wafer when it is picked up.
However, a bumper may be provided at the 3'' end to grip and release the wafer end. in this case,
It is preferable that the bushing be constructed so that it can be retracted to a position where it does not interfere with the μ-wave discharge. 4 to 6 show the implementation of the method using bushings. The bushings Z are numbered and attached to a ring group on the buffer chamber 7, and can be set on the wafer 6 by moving in the radial direction, as shown in the plan view of FIG. Therefore, in this embodiment, when the electrode 5 rises and contacts the leaf spring η attached to the bushing as shown in FIG. 6, grounding for electrostatic adsorption becomes possible, and the wafer 6 is electrostatically adsorbed. can do. Further, in this embodiment, after electrostatic adsorption, the negative electrode 5 is lowered, and when the pusher 4 is separated, the pusher is retracted so as to be drawn in, and the electrode 5 is raised again to start etching.

In a μ-wave etching apparatus, it is common to provide a ground when applying RF, and this ground is provided in a ring shape around the electric field fM5. Therefore, it is desirable that the vacuum interior portion of the buzzer be constructed so that it can be evacuated below this ground. Further, a part of the RF grounding member may be configured to serve as the button 4.

FIG. 7 shows another embodiment. In this embodiment, the bushing is tilted and provided in the buffer chamber 7, so that the wafer 6 can be pressed and grounded even without a stroke of the electric fi5, as shown in FIGS. 4 to 6. There is no need to move the electrode 5 up and down twice as in the embodiment shown in FIG.
Thrubutts can be raised.

When grounding is performed using the bushing described above, an operating mechanism can be provided separately from the wafer transport mechanism, which has the effect of improving the reliability of the apparatus.

Generally, an air cylinder is used for the bushing, but in the case of a low temperature etching apparatus, it is also possible to use a shape memory alloy by utilizing the heat of a low temperature source.

In the above embodiments, the etching process and apparatus have been explained using a μ-wave etching apparatus as an example. However, the present invention also applies to other parallel plate type etching devices! 1ItL? C.V.D.
, It can also be applied to processing and equipment using film forming equipment such as a sputter.

〔Effect of the invention〕

According to the present invention, since a single electrode can be used and the wafer can be adsorbed before plasma generation, plasma processing with high throughput and good temperature control can be performed without deterioration of the withstand voltage of the gate oxide film. effective.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a microwave dry etching apparatus which is an embodiment of the present invention, FIG. 2 is a block diagram showing the ridges of the electrode in FIG. 1, and FIG. 3 is a block diagram showing a second embodiment of the present invention. FIGS. 4 to 6 are block diagrams showing a microwave dry etching apparatus as an example, and FIGS.
The figure is a configuration diagram of the microwave etching device, and Figure 5 is the 4th one.
6 is a detailed view of the bushing, and FIG. 7 is a configuration diagram showing a microwave dry etching apparatus according to a fourth embodiment of the present invention. 5... Electrode, 14... Insulating film, 6...
...Wafer, 8°8'...Arm, n...
...Wafer push-up, 18...DC power supply, 16...High frequency Wlj, 21. Z3...
・・Bubushio map 4th map

Claims (1)

[Claims] 1. A wafer is placed on a single electrode provided with an insulating film, the upper end or end of the placed wafer is grounded and electrostatically attracted, and the ground is removed and plasma processing is performed. . A plasma processing method characterized by releasing the adsorption force after the plasma processing. 2. The plasma processing method according to claim 1, wherein the wafer is electrostatically attracted to the wafer so that different positive and negative charge-ups do not occur within the wafer before the plasma processing. 3. The plasma processing method according to claim 1, wherein a DC voltage is applied to the single electrode also during the plasma processing. 4. The plasma processing method according to claim 1, wherein a high frequency voltage is applied to the single electrode so that a self-bias voltage is applied to the insulating film during plasma processing. 5. The plasma processing method according to claim 1, wherein a cooling gas is introduced into the lower surface of the wafer. 6. A single electrode provided with an insulating film, a transport means for placing a wafer on the electrode, a DC power source for applying a DC voltage to the electrode, and a ground potential applied to the wafer placed on the front electrode. a vacuum container for forming a vacuum atmosphere around the electrode, and a plasma generating means for generating plasma in the vacuum container, and the means for applying the ground potential applies the ground potential to the wafer before generating the plasma. A plasma processing device characterized by being detachable. 7. The plasma processing apparatus according to claim 6, wherein the wafer is grounded by a wafer transfer arm. 8. The plasma processing apparatus according to claim 6, wherein the attraction force is released by a wafer push-up pin after the wafer is attracted and held by applying the DC voltage. 9. The plasma processing apparatus according to claim 8, wherein the potential of the wafer push-up pin is the same as the potential of the single electrode. 10. The plasma processing apparatus according to claim 6, wherein the wafer is grounded using a pusher that grips and releases an end of the wafer.