JPH02143423A - Plasma processing apparatus - Google Patents

Abstract

PURPOSE:To enable an object to be treated uniformly as a whole by adapting a plasma treatment apparatus such that the positional relation of the periphery of an upper electrode to the object can be changed and regulated appropriately. CONSTITUTION:Prior to performing plasma etching, angle of a skirt 15 mounted on an upper electrode 8 is regulated such that optimum uniformity of etching rate can be obtained in the surface of a wafer 1. The angle of the skirt 15 which includes rings 16a-16d superposed one on another can be changed by deviating the rings 16a-16d axially and sequentially in a stepped manner. An angle of the skirt 15 at which optimum uniformity of etching rate can be obtained is determined empirically through experiments or the like and the rings 16a-16d are fixed by a bolt 18 at that angle. When the positional relation of the skirt 15 of the electrode 8 to the wafer 1 is regulated in this manner, the skirt 15 can prevent created plasma and supplied etching from escaping out of the apparatus.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a processing technology, particularly a dry etching technology that performs an etching process using a plasma reaction. ! This invention relates to a technique that can be effectively used to perform an etching process on a wafer in the manufacturing process of a device.

[Conventional technology]

In the manufacturing process of a semiconductor device, a dry etching apparatus is used to perform etching on a thin film 11A on a wafer.The wafer is held by the lower electrodes of parallel flat plates ti arranged above and below, and a high frequency voltage is applied between both electrodes. Some devices are configured to perform etching by converting etching gas, which is supplied in a shower form from an upper electrode onto a wafer, into plasma.

Examples of dry etching techniques using shower electrodes include JP-A-59-43880, JP-A-60-187023, and JP-A-60-9.
There are No. 0629 and Japanese Unexamined Patent Publication No. 163640.

[Problem to be solved by the invention]

However, in such dry etching equipment,
Because only the uniformity of the etching gas flow is considered, and the escape of plasma to the outside of the electrode is not considered, the etching speed is smaller around the wafer than at the center of the wafer, and the uniformity is not improved as much as expected. There is a problem (as revealed by the inventor).

An object of the present invention is to provide a plasma processing apparatus that can perform plasma processing more uniformly over the entire object to be processed.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Means to solve problems]

An overview of typical inventions disclosed in this application is as follows.

That is, in a plasma processing apparatus that includes an upper electrode disposed directly above the object to be treated, and the lower electrode is configured to supply processing gas to the object to be treated to a shower wand, the lower electrode The peripheral portion of the apparatus is configured such that the positional relationship with respect to the object to be processed can be changed.

[Effect]

According to the above-mentioned means, each time the positional relationship of the outer periphery of the upper 1it pole with respect to the object to be processed is adjusted, the plasma and processing gas formed in the space between the upper electrode and the object to be processed are transferred to the upper electrode. Since it is possible to suppress escape to the outside and to generate a velocity electric field concentration near the outer periphery of the upper electrode, it is possible to make the plasma near the object to be processed uniform, thereby making it possible to uniformize the plasma in the vicinity of the object to be processed. Processing speed can be made uniform.

〔Example〕

FIG. 1 is a vertical sectional view showing a dry etching apparatus according to an embodiment of the present invention, FIG. 2 is a partially cutaway bottom view showing an upper electrode, and FIG. 3 is an enlarged partial sectional view thereof.

In this embodiment, the dry etching apparatus according to the present invention includes a processing chamber 2 for processing a wafer 1 as an object to be processed.
The chamber 3 is formed from a main body 4 and a lid body 5 made of stainless steel or the like. The chamber main body 4 is formed in a substantially disk shape with an open top and a closed bottom, and the main body 4 and the lid 5 are connected to each other so that the wafer l
It is configured to be opened and closed for taking in and out.

An exhaust port 6 for exhausting the inside of the processing chamber 2 is provided in the side wall of the main body 4. The lid 5 is made of quartz and has a substantially cylindrical shape, and is detachably placed over the upper opening of the main body 4 to seal the processing chamber 2.

A pair of electrodes 7.8 are horizontally disposed at the lower and upper portions of the processing chamber 2 so as to form parallel plate electrodes. The lower electrode 7 is supported on the bottom wall of the main body 4 via an insulator 9, and is configured to be able to hold one wafer 1 in a six state on its upper surface. The upper electrode 8 is connected to a support shaft 1 inserted into the lid 5 through an insulator 10.
1, and a high frequency type 11IX12 is connected between it and the lower electrode 7. Further, a gas supply path 13 is provided inside the upper electrode 8 and its support shaft 11, and a gas supply path 13 is provided on the lower surface of the upper electrode 8. ! Several gas outlets 14 are opened so that the gas in the gas supply path 13 can be blown out toward the wafer.

A plurality of skirt portions 15 are provided on the outer circumference of the upper TL pole 8. A alignment rings 16a~]Gd are formed by fitting each other, and this skirt portion 15 is connected to the lower m pole 7.
414 so as to be able to adjust the positional relationship with respect to each other. On the outer periphery of the upper electrode 8, a plurality of adjustment rings 16a to 16L (i
The adjustment rings 16a to 16d are arranged so as to be slidably fitted to each other and are externally mounted, and each of the adjustment rings 16a to 16d is arranged in a circumferential direction. The position can be adjusted and replaced by inserting the poles 18 into the long holes 17, which are arranged at several locations and extending in the axial direction, and by screwing them into the side wall of the upper electrode 8. It is possible to be fixed.

Next, the effect will be explained.

The wafer l is at the bottom T1. When placed on the electrode 7 and the inside of the processing chamber 2 is evacuated, an etching gas (for example, S F h , Cz CI F s, etc.) is supplied to the gas supply path 13 and is blown out from the blow-off port 14 of the upper electrode 8 . Along with being
A high frequency voltage is applied between the picture electrodes 7,8 by the power source 12. This causes a plasma etching reaction,
A desired etching process is performed depending on the selectivity between the resist (not shown) deposited on the wafer 1 and the underlying layer.

Incidentally, since the plasma etching reaction depends on the plasma density and etching gas concentration, in the conventional structure of only the shower upper electrode, the etching rate at the center of the wafer is higher than at the periphery of the wafer. That is, in the conventional upper electrode structure, the plasma and etching gas in the periphery of the wafer escape outward, and the plasma and etching gas in the wafer periphery become diluted compared to the central part.

Therefore, in this embodiment, when carrying out the plasma etching operation, the angle of the skirt portion 15 attached to the upper electrode 8 is adjusted in advance so that the uniformity of the etching rate within one wafer surface is the best! J! It will be arranged. That is, since the skirt portion 15 has a structure in which rings 16a to 16d are stacked as shown in FIGS. 2 and 3, each ring 16a to 16d is sequentially shifted in the axial direction in a stepped manner As a result, the angle of the skirt portion 15 can be changed. Then, the angle of the skirt portion 15 that provides the best etching rate uniformity under certain etching conditions is determined by empirical rules such as experiments, and each of the rings 16a to 16d is fixed with bolts 18 in a state that matches the angle.

In this way, when the positional relationship of the skirt portion 15 with respect to the wafer l at the outer peripheral portion of the upper electrode 8 is adjusted,
plasma generated between the upper electrode 8 and the lower electrode 7;
The skirt portion 15 prevents the etching gas supplied therefrom from escaping outward. Further, since a moderate electric field concentration is generated by the skirt portion 15 at the outer circumferential portion of the upper electrode 8, the etching rate is relatively equalized between the peripheral portion and the central portion of the wafer l. The effect of suppressing the escape of plasma and etching gas by the skirt part 15 and the effect of concentrating the electric field at the outer peripheral part are determined by the vertical and radial positional relationship of the skirt part 15 with respect to the shaft 1, that is, the inclination angle of the skirt part 15. The inclination angle of this skirt portion 15 should be adjusted appropriately! I! By adjusting the etch rate, the equalization of the etch rate can be controlled as desired.

According to the embodiment described above, the following effects can be obtained.

(1) By configuring the outer periphery of the upper electrode so that the positional relationship with respect to the object to be processed can be changed and adjusted, the plasma reaction atmosphere formed between the upper electrode and the object to be processed can be vented 5 and the outer periphery. Since the electric field concentration at the skirt part can be controlled by adjusting the positional relationship of the skirt part with respect to the object to be processed, the processing speed can be equalized in the peripheral area and the center area of the object to be processed. The processing state of the entire processing object can be made uniform.

(2) By configuring the skirt part so that a plurality of rings are arranged concentrically with each other and are movably fitted and fixed so that the position can be adjusted, the positional relationship with the workpiece can be improved! liJ
! I! (3) Conventionally, in order to obtain the best etching rate uniformity for each etching condition, multiple standards of upper electrodes were prepared. It is necessary to correspond to each etching condition, but the above (]) and (
2) allows the electrode structure to be made flexible; li can accommodate all etching conditions. As a result, equipment costs can be saved and productivity can be increased.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the Examples and can be modified in various ways without departing from the gist thereof. Nor.

For example, the skirt portion is not limited to being configured by fitting a plurality of rings concentrically to each other, but may be configured to be changeable in shape using a bellows mechanism or the like.

The above explanation mainly describes the case where the invention made by the present inventor is applied to dry etching technology, which is the field of application behind the invention. It can be applied to all types of plasma processing equipment.

〔Effect of the invention〕

A brief explanation of the effects obtained by nine representative inventions among the inventions disclosed in this application is as follows.

By configuring the outer periphery of the upper electrode so that its positional relationship with respect to the object can be changed and adjusted, the plasma reaction atmosphere formed between the upper electrode and the object to be processed can escape, and the electric field can be concentrated in the outer periphery. can be controlled by adjusting the positional relationship of the skirt section to the workpiece, making it possible to equalize the processing speed at the periphery and center of the workpiece, thereby improving the processing status of the entire workpiece. can be made uniform.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing a dry etching apparatus according to an embodiment of the present invention, FIG. 2 is a partially cutaway bottom view showing an upper electrode, and FIG. 3 is an enlarged partial cross-sectional view thereof. l...Wafer (workpiece), 2...processing chamber, 3...
・Chamber, 4...Main body, 5...Lid, 6...Exhaust port, 7...Lower electrode, 8...Upper electrode, 9.10
... Insulator, 11 ... Support shaft, 12 ... High frequency m source, 13 ... Gas supply path, 14 ... Gas outlet, 15
...Skirt part, l[3a-16d...Ring, 1
7... Long hole, 18... Bolt.

Claims (1)

[Scope of Claims] 1. Plasma processing comprising an upper electrode placed directly above the object to be processed, and the upper electrode is configured to supply processing gas to the object to be processed in the form of a shower. 1. A plasma processing apparatus, wherein the upper electrode is configured such that the positional relationship of its peripheral portion with respect to the object to be processed can be changed. 2. The upper electrode has a skirt portion on its outer periphery,
2. The plasma processing apparatus according to claim 1, wherein the skirt portion is constructed by slidably fitting each of a plurality of cylinders.