JPS63185032A - Etching apparatus for silicon substrate - Google Patents

Abstract

PURPOSE:To make it possible to perform reaction treatment corresponding to silicon substrates and to reduce dispersion in parallelism, by providing a holder, which supports a plurality of the silicon substrates so that the substrates can be rotated, and providing a liquid-flow providing means in a reaction bath containing etching liquid. CONSTITUTION:The temperature of etching liquid 14 is controlled by means of a heat exchanger 25. The liquid 14 is pressed into a reaction bath 11 with a plurality of pumps 19. In etching work, a dummy wafer is etched, and parallelism is measured with an interference-fringe measuring instrument. A variable- flow-rate valve 24 is adjusted so that an adequate flow rate is obtained. Namely, the amount of the etching liquid 14 corresponding to the parallelism of a plurality of silicon substrates 15 is jet into the reaction bath 11. Meanwhile, a holder 13, which holds a plurality of the silicon substrates 15, is rotated at the number of rotation that does not disturb the flow of the liquid. Thus the silicon substrates 15 are contacted with the flowing etching liquid 14 and undergo reaction treatment. The liquid, which is injected into the reaction bath 11, overflows and returns to a well 18 through a returning pipe 23.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a silicon substrate etching apparatus using an etching solution.

(Prior Art) As shown in FIG. 5, a conventional etching apparatus fills a reaction tank 1 with an etching solution 2, and a holder fixing shaft 3 is placed in the reaction tank 1.
It has a structure in which a rotatably driven holder 4 supported by a holder 4 is immersed, and a large number of silicon substrates 5 are held between the holder 4 and rotated together with the holder 4 to perform etching. Therefore, the silicon substrate 5 is subjected to a reaction treatment by contact with the stationary etching liquid 2, and the contact with the etching liquid 2 is as follows.
It depends exclusively on the rotational movement of the silicon substrate 5.
・ (Problems to be solved by the invention) However, ``the etching apparatus described above does not remove the silicon substrate 5.
When subjected to reaction treatment, variations in parallelism occur between the large number of silicon substrates S, S, etc. held by the negative holder 4. That is, as described above, since the silicon substrate 5 is rotated at a high speed, the silicon substrate 5
It is not possible to control the state of contact with the etching liquid 2. Therefore, variations occur in the contact between the silicon substrate 5 and the etching liquid 2, and as a result, variations in parallelism occur between the silicon substrates 5.5.

(Means for Solving the Problems) The present invention has been made to solve the above problems.
The following technical measures will be adopted.

That is, the present invention provides a silicon substrate etching apparatus comprising a holder for rotatably supporting a plurality of silicon substrates and a reaction tank in which the holder is housed and an etching solution. It is constructed by attaching means.

(Function) According to the above configuration, in addition to high-speed rotation of the silicon substrate, the etching solution itself flows, promoting contact between the silicon substrate and the etching solution, and eliminating variations in parallelism of the silicon substrate. be done.

(Example) Hereinafter, the present invention will be explained in further detail based on illustrative drawings.

FIG. 1 is a front view showing an embodiment of the present invention, and FIG. 2 is a side view of the same, in which 11 is a reaction tank, 12 is a holder fixing shaft, 1
3 is a holder, 14 is an etching solution, 15 is a silicon substrate, and 16 is a thermocouple.

The silicon substrate etching apparatus of the present invention includes a liquid flow providing means 17.

That is, in the present invention, a storage tank 18 containing an etching liquid 14 is disposed near the reaction tank 11, and the etching liquid 14 in the storage tank 18 is supplied to the reaction tank by a pump 19 and a plurality of independent supply pipes 20. The etching solution 14 is introduced into a divided tank 21 provided at the bottom of the reaction tank
It is ejected from a multi-divided spout 22 formed at the bottom of 1,
On the other hand, a return pipe 23 is provided between the upper part of the reaction 4%"jLl and the storage tank 18, and the used etching solution 14 is transferred to the storage tank 18.
It is configured to return to Reference numeral 24 designates a plurality of variable flow rate valves attached to each supply pipe 20 independently from each other, and 25 designates a heat exchanger provided in the storage tank 18.

The etching apparatus according to the present invention described above is used as follows.

First, a thermocouple 16 disposed in the reaction tank 11 measures the liquid temperature, and a heat exchanger 25 provided in the storage tank 18 controls the liquid temperature.

The temperature-controlled etching liquid 14 is supplied by a plurality of pumps 19.
At that time, the flow rate is adjusted using a variable flow valve 24 attached to the supply pipe 20. Specifically, when etching is performed, a dummy wafer is etched, parallelism is measured with an interference fringe measuring device, and the variable flow rate valve 24 is adjusted to obtain an appropriate flow rate. In other words, the etching liquid 14 is suitable for the parallelism of the plurality of silicon substrates 15 in the holder 13.
is ejected into the reaction tank 11. FIG. 3 is a graph showing the correlation between the flow rate of the etching liquid 14 and the thickness unevenness. For example, at a flow rate of 4041/win, the thickness unevenness is 1 to 3 gm. From this graph, the thickness unevenness becomes smaller as the flow rate increases, but 50! It can be seen that there is no value in increasing the flow rate above L/+sin.

On the other hand, the holder 13 holding the plurality of silicon substrates 15 is rotated at a rotation speed (for example, 50
Rotate at rp■±5rp■).

Thus, the silicon substrate 15 is exposed to the flowing etching solution 1.
The liquid injected into the reaction tank 11 overflows and returns to the storage tank 18 through the return pipe 23.

(Effects of the Invention) As explained above, the present invention is configured to include a liquid flow providing means, and reacts a silicon substrate with the liquid flow. Therefore, by changing the flow rate, a reaction suitable for the silicon substrate can be achieved. processing becomes possible, and the variation in parallelism, which was large in the past, becomes smaller.

FIG. 4 is a distribution diagram of thickness unevenness when the etching apparatus according to the present invention is used, and compared to FIG. 6 (when conventional bags are used), the remarkable effect of the present invention can be seen.

In these figures, the vertical axis is the number (n), the horizontal axis is the thickness unevenness (pm), where N is the number of tests, X is the arithmetic mean, and σ
indicates the standard deviation of the distribution.

[Brief Description of the Drawings] Fig. 1 is a front view showing one embodiment of the present invention, Fig. 2 is a side view of the same, Fig. 3 is a correlation diagram between liquid flow rate and etching thickness unevenness, Fig. 4 5 is a front view showing a conventional device, and FIG. 6 is a distribution diagram of thickness unevenness in the case of using the conventional device. 11...Reaction tank 13...Holder 15...Silicon 17...Liquid flow imparting means Patent applicant Kyushu Electronic Metals Co., Ltd. (Train 1) Agent Patent attorney Masazumi Mori Figure 3 Figure 4 Collar outside the figure! Sugar n * area whole': S Kankatatami, 's@-'s pust

Claims (1)

[Claims] In a silicon substrate etching apparatus comprising a holder that rotatably supports a plurality of silicon substrates and a reaction tank that houses the holder and contains an etching solution, the reaction tank is provided with a liquid flow providing means. Characteristic silicon substrate etching equipment.