JPH069131U - Pellet etching equipment - Google Patents

Abstract

(57) [Summary] [Purpose] Generally, it is difficult to stir the etchant uniformly, and uneven etching is inevitably caused on the pellet surface, which increases the leakage current in the completed thyristor and reduces the switching speed. This is to eliminate this etching unevenness. [Structure] An etching tank that is rotated by a motor and has blades fixed inside, a sample stand that is attached to a stay that is inserted into the etching tank, and a blade is provided on the lower part of the sample stand, and a semiconductor substrate is provided on the upper part. And a rotator connected so as to be rotatable through the sample table.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a pellet etching device.

[0002]

[Prior art]

 A conventional pellet etching apparatus is shown in FIG. 5, and an etching bath 2 contains an etching liquid 2. Then, the pellet 3 is set in the etching solution 2 so that it can be etched. When etching is performed with such an apparatus, the etching bath 1 is inclined and rotated so that the etching liquid on the surface of the pellet 3 is always convected. This means that the surface of the pellet 3 is always uniformly etched.

[0003]

[Problems to be solved by the device]

 However, it is difficult to uniformly stir the etching solution in the etching device with such a structure, and uneven etching is inevitably generated on the pellet surface, which increases the leakage current in the completed thyristor and causes switching. The result is a slowdown. The present invention has been made in view of the above-mentioned points, and an object of the present invention is to provide a pellet etching apparatus which does not cause uneven etching on the pellet surface.

[0004]

[Means for Solving the Problems]

 In other words, the means for achieving that purpose are: an etching tank that is rotated by a motor and has blades fixed inside; a sample stand that is attached to a stay that is inserted into this etching tank; It has blades and a table on which a semiconductor substrate is set, which is composed of a rotor rotatably connected via the sample table.

[Operation] The operation will be described in combination with the embodiment described below. An embodiment of the present invention will be described below in detail with reference to the drawings.

[0005]

【Example】

 FIG. 1 is an explanatory view showing an embodiment of the present invention, FIG. 2 is an explanatory view of a pellet, FIG. 3 is an explanatory view showing a measurement portion, and FIG. 4 is a comparative drawing of etching unevenness between a conventional device and the present invention. In FIGS. 1 and 2, an etching tank 5 which is rotated by a motor (not shown) and has blades 4 fixed at a plurality of internal positions, and a sample table 7 which is attached to a stage 6 to be inserted into the etching tank 5. The sample table 7 has a blade 8 at the lower part, and the upper part has a table 9 for setting the semiconductor substrate, that is, the pellet 1, which are connected via the sample table 7 so as to be rotatable. It is composed of a rotor 10 and a rotor. The axis of the rotor 10 is slightly offset from the axis of the etching tank 5 so as to be eccentric. Moreover, the shape of the blade 8 is formed so as to enhance the convection effect with respect to the depth of the etching tank 5. Further, a slide ball 11 is provided on the sample table so that the rotor 10 can rotate on the sample table 7. Here, in FIG. 2, 12 is, for example, a Si plate, 13 is an etching mask, 14 is an etching amount, and 15 is an etching surface.

Next, the operation will be described. When etching the pellet 1, the pellet 1 is set on the rotor 10 and the etching bath 5 is rotated. The blades 8 of the rotor 10 rotate with the rotation of the etching solution 2, and convection of the etching solution 2 occurs in the etching tank 5. As a result, a new etching solution 2 is constantly circulated on the surface of the pellet 1 and the surface of the pellet 1 is uniformly etched. FIG. 4 shows the amount of etching at four outer peripheral end portions of the pellet 1 shown in FIG. 3 measured using ten samples. As shown in Fig. 4, the conventional pellets show an etching unevenness of up to 40 microns, but according to the present invention, it is possible to suppress the etching unevenness to several microns. This also reduced the leakage current in the experiment.

[0007]

[Effect of device]

 As described above, according to the present invention, the motor is rotated by the motor and the blades are fixed inside the etching tank, the sample table is attached to the stay to be inserted into the etching tank, and the sample table has the blades at the bottom. However, there is a table for setting the semiconductor substrate on the upper part, and since these are composed of a rotor connected so as to be rotatable through the sample table, the etching unevenness is extremely smaller than that of the conventional one. It was

[0008]

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a main part of FIG.

FIG. 3 is an explanatory diagram showing a measurement portion of FIG.

FIG. 4 is a comparative diagram of etching unevenness.

FIG. 5 is an explanatory diagram showing a conventional example.

[0009]

[Explanation of symbols]

 1 etching tank 2 etching liquid 3 pellets 4 blades 5 etching tank 6 stays 7 sample stage 8 blades 9 units 10 rotor 11 ball 14 etching amount 15 etching surface

Claims (1)

[Scope of utility model registration request] 1. An etching tank which is rotated by a motor and has blades fixed therein, a sample stand attached to a stay to be inserted into the etching tank, and a blade on the lower part of the sample stand, and an upper part A pellet etching apparatus comprising a stage for setting a semiconductor substrate, and a rotor which is rotatably connected via the sample stage.