JPH03234023A - Etching device for mirror finishing of semiconductor wafer - Google Patents

Abstract

PURPOSE:To improve etching characteristics by providing means for rotating containers of etchant both on their axes and on the axis of the table on which they are placed. CONSTITUTION:A plurality of holders 8 are fixed on a table 9, and a container 7 of liquid etchant 3 is placed in each bolder. A wafer 1 is put in each container for etching. The table 9 is rotated by a motor 18 through a gear train, and simultaneously the holders 8 are also rotated through a gear train. As a result, the wafer makes complex movements by the rotation of both the table and holder. Therefore, it is possible to process a plurality of wafers simultaneously while eliminating irregular etching.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application J] The present invention relates to a mirror etching apparatus for semiconductor substrates.

[Prior Art 1] After the surface of a semiconductor substrate (hereinafter referred to as ``C'') is mirror-finished by chemical and mechanical polishing, an etching process is further performed to remove the remaining process-affected layer. L
When performing the etching process, the etching pattern must be constant over all wafers being processed, the etched wafer must maintain the flatness obtained by polishing, and the wafer surface must be free from etching unevenness, waviness, etc. In addition, from the viewpoint of productivity and cost, processing time per sheet is required to be short.

FIGS. 3 and 4 show an example of a conventionally used single-wafer etching apparatus that processes a large number of wafers at the same time using a multi-wafer type uneven etching process and a beaker work. In both figures, 1 is a wafer, 2 is a carrier that supports the wafer 1, 3 is an etching solution, 4 is an etching tank, 5 is an arm that operates the carrier 2, and 6 is a beaker.

In the device shown in FIG.
is immersed in etching solution 3. l-ty') 72 is given vertical and horizontal movement or rotational movement by arm b. After one tweezing for a predetermined period of time is completed, the carrier 2 is transported by the arm 5 and washed in a pure water tank.

At position 'fA' in FIG. 4, the etching plate 1 is placed in the etching liquid 3 in a horizontal position, and etching is performed by rotating and swinging the etching in this state. The pure water cleaning is performed by instantaneously pouring most of the pure water into the beaker 6.

[Problems to be Solved by the Invention] As mentioned above, etching apparatuses can be roughly divided into multiple wafer processing apparatuses (e.g., Fig. 3) and single wafer processing apparatuses (e.g., Fig. 4), each of which has advantages and disadvantages. .

In the case of a multi-wafer simultaneous processing device, the number of sheets processed per unit time is large and the productivity is excellent, but on the other hand, J-etching unevenness occurs at the contact area between the outer periphery of the T and the carrier, worsening the mirror surface condition and causing problems in the etching tank. The etching liquid flowing on the mirror surface leaves traces when it is pulled up from 4 or during transportation. Furthermore, a large amount of etching solution is required, which may lead to an increase in the size of the apparatus due to waste liquid treatment, etc. On the other hand, in the case of single wafer processing equipment, uniform
Although it has the advantage of producing a very smooth etching solution and does not leave any etching residue, it has the disadvantage that it is extremely difficult to mass-produce.

SUMMARY OF THE INVENTION An object of the present invention is to provide a mirror etching apparatus for semiconductor substrates that is highly productive and provides good etching characteristics.

Means for Solving Problem 1] The present invention provides a mirror etching apparatus for semiconductor substrates that removes process-altered particles 1 remaining on the surface after polishing to give a mirror finish. The first feature is that it has a means for swinging by movement, and the second feature is that the revolution and rotation of this etching container is based on a rotation system that is a combination of a heptad and gears. The revolution and rotation are
The third feature is that the direction and speed change periodically, and the objective is to be achieved by improving productivity and etching performance.

[Function] According to the present invention, in the specular etching apparatus for conductive substrates, containers containing etching liquid are placed on t=number of pedestals which are fixed to the r-pull, and the wafer is placed in the pedestals. The wafer is rotated through a gear system by the Tanabata rotation, and at the same time the pedestal is rotated by a series of gear systems to perform etching, so the wafer has both orbital movement due to the rotation of the table and rotational movement due to the rotation of the pedestal. As a result, complicated rocking is performed, and etching unevenness that tends to occur during etching can be completely removed while processing a plurality of wafers at the same time. Furthermore, since this revolution and rotation movement can change its direction and speed periodically - good results can be obtained.

[Example J Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
The figure is a sectional view showing one embodiment of the mirror etching apparatus for semiconductor substrates of the present invention, and FIG. 2 is a plan view of the gear system shown in FIG. 1. In both figures, 1 is the etching liquid, 7 is the etching container, 8 is the pedestal for the container 7, and 9 is the etching liquid.
10 is a sun gear, 11 is an idle gear that meshes with the sun gear 10, 12 is a planetary gear that meshes with the idle gear 11, 13 is a shaft made integrally with the cradle 8, and 14 is a block. ) A pin that fixes the net gear 12 and the shaft 13, 15 is a shaft screwed to the table 9, 16 is a nut that rotatably attaches the idle gear 11 to the shaft 15, and 17 is a cylindrical support that supports the pedestal 8. It is screwed to the table 9. 18
is the motor.

As shown in both figures, the etching container 7 is placed on a pedestal 8, and the pedestal 8 is placed on a cylindrical support 17. The cylindrical support 17 is fixed to the table 9 with bolts. A shaft 13 is attached to the opposite side of the pedestal 8, and the shaft 13 is fixed to the planetary gear 12 by a pin 14. The planetary gear 12 meshes with the idle gear 11, and the idle gear 11 is attached to the restable 9 by a shaft 15 and meshes with the ring gear 10.

The sun gear 10 is fixed to the device Togane.

In this state, when the motor [epsilon]3 is rotated, the table 9, which is connected to the seven-piece safety shaft, rotates accordingly. When the j-pull 9 rotates, the pedestal 8 and the planetary gear 1
2. The idle gear 11 rotates around the angle gear V10. This is the orbital motion. Since the sun gear 10 is fixed to the frame, the idle gear 11 meshes with the sun gear 10 and rotates, and this rotation causes the planetary gear 12 to rotate. The rotation of the planetary gear 12 is transmitted to the pedestal 8 by the shaft 13, and the pedestal 8 rotates. This is rotational motion.

In this case, the number of teeth of the sun gear 10 and the planetary gear 12 are made equal, and a single wafer etching method (
The same operation as in FIG. 4) can be performed. Furthermore, by operating the tllllll system of the motor 18 and periodically changing its rotational direction and rotational speed, *rough etching operations can be performed.

Using this device, etching was carried out on a 3" diameter V insulating gallium arsenic (GaAs) wafer. H2SO4 used in the 1st Lung: l-+2o2
:H2O-5:1:1 solution was used, the temperature was 60°C, the number of sheets to be processed was 4, the motor rotation speed was 42r, p, a+, 5
The rotation was reversed for each rotation, and the rotation speed was set to 60r, p, a+ for 1/44 rotation in one rotation.

This connection beam has a flatness of TTV (TTV) before etching.
tal rhickness Variatio
n) was 2,5-3.0 am,
Although approximately 8 μm was removed by etching for 1 minute, the TTV after etching was 2.8 to 3.5 μm, showing almost no change compared to before etching.

In addition, the surface of the plate was smooth without any etching liquid unevenness or waviness, which was a significant improvement over the conventional multi-plate type.

The processing time is 3 minutes per sheet, which is slightly slower than the conventional multi-sheet method, but it is about 4 times faster than beaker work! l! 1 instant speed was obtained.

[Effects of the Invention 1 As described above, according to the present invention, the following effects can be obtained.

(1) It is possible to obtain a smooth mirror surface that is caused by uneven etching, waviness, etc.

(2) The flatness obtained by polishing can be maintained.

(3) Since a large number of etching processes can be performed simultaneously without increasing the size of the apparatus, productivity can be greatly improved.

(4) It is possible to reduce the -J stress of the product by improving productivity.

[Brief explanation of drawings]

1 and 2 are a cross-sectional view and a plan view of a gear system showing an embodiment of a mirror etching apparatus for semiconductor substrates according to the present invention, and FIGS. 3 and 4 are a conventional multi-processing type etching apparatus and a single-wafer etching apparatus. FIG. 2 is an explanatory diagram of a type etching apparatus. 1: Wafer. 3: Etching liquid, 0 1 2 3 8: Container, : Table, Niring gear, : Idle gear, : Planetary gear, : Shaft, : Motor. Old Day Day ■

Claims (1)

[Scope of Claims] 1. In a mirror etching apparatus for semiconductor substrates, which removes the process-affected layer remaining on the surface after finishing polishing to give it a mirror-like finish, the container used for etching is shaken by revolution and rotation. 1. A mirror etching apparatus for a semiconductor substrate, comprising a means for moving a semiconductor substrate. 2. The mirror etching apparatus for semiconductor substrates according to claim 1, wherein the revolution and rotation of the etching container is performed by a rotation system formed by coupling various gears. 3. The mirror etching apparatus for a semiconductor substrate according to claim 2, wherein the revolution and rotation movements are performed by periodically changing the direction and speed.