JPS5821335A - Etching method for semiconductor wafer - Google Patents

Abstract

PURPOSE:To homogenize etching, by controlling the temperature of a liquid while providing a wafer with a rotation and up-down movements and generating bubblings in the lower part of the liquid when chemical etching by containing a semiconductor wafer after a finish lapping in an etchant bath. CONSTITUTION:A cylindrical rotary cage 2 wherein a plurality of semiconductor wafers 1, 1' are contained is provided in the etchant bath 3, the bath 3 is filled with the etchant 4, and a temperature detection part 5 is hung down thereto. Next, the etchant is heated to a fixed temperature by a heater 6 provided in a pipe for circulation of the liquid 4 according to the detected temperature, and simultaneously the cage 2 is rotated and moved up and down. In this constitution, further, a spouting part 10 having many spouting holes on the upper surface is provided on the bottom surface of the bath 3, an air or a non-oxidizing gas such as N which well protects the etchant is made to spout therefrom resulting in bubblings. In this manner, the difference in upper and lower temperature of the etchant 4 is eliminated, and flat etching can be performed.

Description

[Detailed description of the invention] The present invention relates to a method for etching semiconductor wafers.

A semi-integrated wafer on which semiconductor elements are formed is manufactured by slicing a semiconductor ingot into a wafer shape, which is then subjected to processes such as lapping, chemical etching, and boring. Improvements are being made to reduce warpage in the slicing process and to improve parallelism and flatness of both principal surfaces in other processes. Recently, semiconductor wafers have become larger in diameter, for example, 100 mm in diameter, and as the patterns in semiconductor devices become finer, there is a strong demand for improved flatness and other properties. (It's getting worse.

Traditionally, it is the first type of traditional etching applied to 2-pings.
The etching process was carried out as follows using an etching device as shown in the figure. That is, a plurality of semiconductor wafers (1),
(1')... are placed in a cylindrical rotating cage (2) that stores horizontally and in multiple stages, and placed in an etching liquid tank (3).
immerse it in the etching solution (4). A temperature detecting section (5) and a heater (6) interlocked with the temperature detecting section (5) are installed so that the etching solution is maintained at a desired temperature. The rotating cage also rotates in the liquid around a cylindrical axis. Further, at the same time as the rotation, vertical movement is also performed.

The above-mentioned conventional etching method has the disadvantage that a temperature difference is generated between the etching center (the upper part and the lower part of the etching solution). For this reason, uniform etching cannot be performed and the precision of wrapping is impaired, so countermeasures have been required.

This invention was made in order to improve the drawbacks of the above-mentioned conventional method.
The semiconductor wafer is rotated and moved up and down in the etching solution, the temperature of the solution is controlled, and the etching solution is bubbled in the lower part of the etching solution to eliminate the temperature difference between the upper and lower parts of the etching solution.

The invention will be explained in detail below with respect to one embodiment.

The etching apparatus used in method 62 of this invention is as shown in FIG. 2, in contrast to the conventional apparatus shown in FIG. Differently, the etching method is the same as the conventional method in that the rotation and vertical movement of the semiconductor wafer and the liquid temperature are controlled, but in addition to these, bubbling is applied to the lower part of the etching liquid.

The intensity of this bubbling is experimentally adjusted depending on the size, depth, etching time, etc. of the etching container. In addition, the fumarole gas for bubbling with may be air, but
A non-oxidizing gas such as an electron is suitable for storing the etching solution.

According to Jin's invention, the temperature difference between the upper and lower parts of the etching solution is extremely reduced, the uniformity of etching is improved, and the desired flat etching can be achieved. In addition, in conventional etching methods, there was generally a temperature difference of around 10°C and a difference of about twice the etching speed, but according to the example, the temperature difference was less than 1°C, making it possible to chemically etch large-diameter semiconductor wafers. make it good.

[Brief explanation of the drawing]

Figure si is a sectional view schematically showing a conventional chemical etching apparatus, and Figure 2 is a sectional view schematically showing a chemical etching apparatus of the embodiment. 1, l'... Semiconductor wafer 3 Etching liquid tank 4 Etching liquid 10 (Bubbling) Blower agent
Patent Attorney Inoue - Male

Claims (1)

[Claims] After final lapping, the semiconductor wafer is subjected to chemical etching in an etching liquid bath (characteristics include rotation and vertical movement of the semiconductor wafer in the etching liquid, liquid temperature control, and aS nibbling under the etching liquid). A method for etching semiconductor wafers.