JPH02267967A - Manufacture of semiconductor element - Google Patents

Abstract

PURPOSE:To improve the adhesion of a passivation material to a semiconductor substrate and to make possible the formation of a stable electrode film by a method wherein a substrate surface region which comes into contact to a mesa groove formation region is roughened by sandblasting. CONSTITUTION:The surface of a silicon substrate 1 is covered with a resist film 5, which is used as a maskant, excepting the formation region of a mesa groove 4 and a wet etching is performed. As the edge part of the film 5 coats a sandblasted region 3 of the surface of the substrate 1, the film 5 is closely adhered to the substrate 1 at this region and is never peeled from the substrate 1. As a result of the wet etching, the groove 4 is formed, a p-n junction is exposed on the inner surface of the groove and a junction covering resin 6 which is used as a passivation material is applied on this exposed surface, but as the end part of this resin 6 is also closely adhered to the sandblasted region 3, the resin 6 is never peeled from the inner surface of the groove 4. After that, a metal film is deposited on the exposed surface of the substrate 1. Thereby, the substrate surface is smoothened, the deposited film is closely adhered to the substrate surface and a stable electrode film is obtained.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention involves applying a masking agent to the surface of a semiconductor substrate having at least one pn junction, and etching the portion not covered with the masking agent to form a mesa groove. A semiconductor device is manufactured by forming a pn junction on the inner surface of a mesa groove, coating the exposed pn junction with a passivation material such as glass, polyimide, or junction coating resin (JCR), and then depositing a metal electrode film on the substrate surface. Regarding the manufacturing method.

[Conventional technology]

When manufacturing semiconductor devices, a mesa groove is formed by wet etching to expose a pn junction from one surface of a semiconductor substrate to the inner surface, the exposed surface of the pn junction is covered with a passivation material, and a metal electrode film is further coated on the substrate surface. This is known as a method suitable for mass-producing elements with high reliability. Conventionally, as such a manufacturing method, for example, pn
A photoresist, polyimide, etc. is applied as a masking agent onto the S10 film covering the surface of the silicon substrate on which the bond is formed, and a mask with an arbitrary pattern is formed by photoetching, and then wet etching is performed, and after the etching is completed. The masking agent was removed and the exposed pn junction was coated with a bashing material such as glass, polyimide, or bonding coating resin. Another method is to perform sandblasting on the entire surface before wet etching to remove the 310% of the silicon substrate surface. ．． After removing the film and leaving it in a rough state, we perform buttering and wet etching using photoresist, polyimide, etc. as a masking agent.
After etching, the masking agent is removed or left as is, and the exposed pn junction is coated with glass, polyimide, bonding coating resin, or the like.

[Problem to be solved by the invention]

In conventional manufacturing methods, if sandblasting is not performed at all before wet etching, the adhesion between the masking agent and the semiconductor substrate is weak, and in the worst case, the masking agent may peel off before wet etching of the mesa groove. Also, when coating the exposed pn junction, the adhesion of the bancibasin material was poor, which was a problem. On the other hand, on the surface sandblasted before wet etching, the adhesion of the mask agent is good, but the adhesion of the vapor deposited film is poor, making it impossible to form a stable electrode film by vapor deposition when attaching the electrodes. Electroless plating must be used to deposit metal films onto semiconductor substrates, but in that case the plating solution is glass.

There has been a problem in that it has an adverse effect on films made of pansibasin materials such as polyimide and JCR, resulting in unstable properties.

An object of the present invention is to solve the above-mentioned problems and to improve the adhesion of the mask to the substrate during wet etching for forming mesa grooves, the adhesion between the bancibasin material and the exposed pn junction, and the adhesion between the metal electrode and the substrate surface. An object of the present invention is to provide a method for manufacturing a good semiconductor device.

[Means to solve the problem]

In order to achieve the above object, the present invention applies a masking agent to one surface of a semiconductor substrate having at least one pn junction, and forms a mesa groove by etching the portion not covered with the masking agent. A method for manufacturing a semiconductor device, comprising: exposing a pn junction on an inner surface of a mesa groove; coating the exposed pn junction with a puffy basis material after removing a masking agent; and further depositing a metal electrode film on at least one surface of a semiconductor substrate. , before applying the masking agent, a slightly wider area of the oxide film on the one surface of the semiconductor substrate including the mesa groove formation region is removed, and then the exposed semiconductor substrate surface is roughened by sandblasting.

[Effect]

By sandblasting an area slightly wider than the mesa groove formation area on the semiconductor substrate surface, removing the oxide film existing in that area and making the surface rough, the masking agent deposited on the semiconductor substrate except for the mesa groove formation area has a rough edge. Since it adheres to the rough surface, the adhesion of the masking agent to the substrate surface is improved. After forming a mesa groove by etching, when the masking agent is removed and the exposed pn junction is covered with a puffy basis material, the edge of the puffy basis material film adheres to the rough surface of the substrate, so the contact between the puffy basis material and the substrate is Adhesion is also improved. Moreover, since the substrate surface other than the vicinity of the mesa groove is not roughened, it is possible to form a stable electrode film by vapor deposition.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4. Figure 1 (5), (bl, tel) shows the surface roughening process of the silicon substrate, (8) is a plan view, (b) is a cross-sectional view, (C) is an enlarged view of part A of (b). A part 3 of 5tozll*2 covering the surface of the silicon substrate on which a pn junction parallel to the 0 surface was formed was removed by selective etching. This is a region on the can plate with a width equal to the width of the mesa groove. Then, this S10. Region 3 from which the film 2 was removed was roughened by sandblasting.
al, (b), and (c) show the etching process of the mesa groove, and similarly to FIG. 1, (a) is a plan view, (b) is a sectional view, and (C) is an enlarged view of the (blOA part). In this step, a resist film 5 is used as a masking agent in areas other than the area where the mesa groove 4 is formed.
and wet etching.

Since the edge of the resist film 5 is deposited on the sandblasted area 3 on the surface of the silicon substrate 1, it adheres closely to the substrate in this area and does not separate from the substrate.As a result of wet etching, the mesa groove 4 is formed. is formed, and a pn junction is exposed on its inner surface. In FIG. 3, the exposed surface of the pn junction is coated with a bonding coating resin 6 as a pansibasin material.

Since the edge of this bonding coating resin 6 also adheres to the sandblasted area 3, it will not peel off from the inner surface of the mesa groove 4. According to the method, the bonding coating resin 6 is masked and the film 2 on the surface is removed by etching, and then the metal film 7 is deposited on the exposed surface of the silicon substrate 1 as shown in FIG. The deposited film adheres closely, and a stable electrode film 7 is obtained.

〔Effect of the invention〕

According to the present invention, by roughening the surface area of the semiconductor substrate in contact with the mesa groove forming area by sandblasting, a masking agent is applied to areas other than the mesa groove forming area, and a pansive material is coated on the inner surface of the mesa groove. The edges adhere to the roughened area and will not peel off, and electrodes can be stably attached to the non-roughened areas, making it possible to manufacture highly reliable semiconductor devices.

[Brief explanation of drawings]

Figure 1 (al, Cbl, fcl shows the roughening process of one embodiment of the present invention, fat is a plan view, (b) is a sectional view, (C) is an enlarged view of part A of (bl, second Figures (al, (b)
l, (C1 shows the mesa groove forming step of one embodiment of the present invention, (4) is a plan view, (b) is a cross-sectional view, (C) is (bl
An enlarged view of the OA part, FIG. 3 is a cross-sectional view showing the puff sealing process of an embodiment of the present invention, and FIG. 1: Silicon substrate, 2: Sin, film, 3: Sandblasting area, 4: Mesa groove, 5: Resist film, 6: Bonding coating resin, 7: Metal bridge film, -7 proxy 4t
Jχ soil Iwao Yamaguchi

Claims (1)

[Claims] 1) Apply a masking agent to one surface of a semiconductor substrate having at least one pn junction, and form a mesa groove by etching the portion not covered with the masking agent to expose the pn junction on the inner surface of the mesa groove, and then apply the mask. In a method for manufacturing a semiconductor device, the method includes covering the exposed pn junction with a passivation material after removing the masking agent, and further depositing a metal electrode film on at least one surface of the semiconductor substrate. After removing a slightly wider area including the mesa groove formation area of the oxide film existing on the one surface of the oxide film,
A method for manufacturing a semiconductor device, characterized by roughening the exposed surface of a semiconductor substrate by sandblasting.