JPS63312645A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent a passivation film from being stepwisely cut by providing the step of finishing to form a smooth shape by etching the end of a step by using the step of accurately removing it except a mesa region by a dry etching method and a wet etching method. CONSTITUTION:A semiconductor substrate 1 is covered with a photoresist 2, and patterned to expose the substrate 1 in a window 2' state in a region for surrounding a mesa forming region. Thereafter, the substrate 1 is selectively etched by dry etching to form a mesa groove 3. Subsequent to the dry etching, a wet etching is conducted. The corners of a mesa groove 4 are rounded by the wet etching.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a semiconductor device, and particularly to a method of forming a mesa structure of a semiconductor device.

[Conventional technology]

Conventionally, the method for forming this type of mesa structure is to use a photoresist process to form seven areas on a semiconductor substrate.
Seven photoresists were formed so as to be surrounded by photoresist grooves, and then the portions of the semiconductor substrate exposed to the photoresist grooves were etched by a wet method, thereby forming a mesa structure.

[Problem that the invention seeks to solve]

The conventional method described above uses photoresist, which is an organic material, as the substrate material. For this reason, when performing wet etching, the photoresist does not have sufficient resistance to the etchant. In other words, most etchants cause an exothermic reaction, which deteriorates the adhesion of the photoresist to the semiconductor substrate, making it difficult to obtain the desired mesa structure as the mesa groove becomes wider or its shape is distorted. That's six.

Although various waxes are excellent as a means of solving the above-mentioned drawbacks, they are difficult to form grooves with high precision and are inferior in terms of 8 degrees, making it difficult to obtain the desired shape.

The above-mentioned conventional methods have drawbacks such as durability, heat resistance, or accuracy, which causes poor characteristics and reduced yield.

[Means for solving problems]

The purpose of the present invention is to eliminate the above drawbacks and improve the mesa structure with high precision.
It is an object of the present invention to provide a method for manufacturing a mesa structure in which problems do not occur even in subsequent steps.

That is, according to the present invention, using a dry etching method,
The process includes a process of removing areas other than the desired mesa area with high precision, and then a process of etching the reduced part of the stepped part in particular using a wet etching method to finish it into a smooth shape.The present invention According to the authors, since etching to create mesa grooves in semiconductor substrates is carried out by dry etching, ordinary photoresist can be used as the etching mask material, and since the finishing is done by wet etching afterwards, the shape of the mesa part can be easily adjusted. This makes the surface smooth and prevents breakage, etc. due to subsequent formation of a passibele film.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIGS. 1(a) to 1(d) are cross-sectional views of one embodiment of the present invention! (a) shows the completed cross-sectional view. First, a semiconductor substrate 1 is formed in the shape of a window 2I in an area surrounding the area shown in FIG.

After that, the semiconductor substrate 1 is selectively etched by dry etching to form a mesa groove 3 (FIG. 1(C)).
. Next, as shown in FIG. 1(d), wet etching is performed following dry etching. (Figure 1 (
d)). By this wet etching, the corners of the mesa groove 4 are rounded.

By carrying out the above steps (C), sharp etching grooves are formed in the semiconductor substrate and the shape becomes smooth.

According to another embodiment of the present invention, a desired metal mask is placed on the semiconductor substrate 1, as shown in FIG. 1(b). Next, the protect wax is heated and turned into a liquid, which is then sprayed onto the substrate from above the metal mask. Next, the hot plate (
Place the board on top (200℃) and melt the wax using a strong
Let's call it 2. Thereafter, as shown in FIG. 1 (C1), the semiconductor substrate 1 is etched by dry etching. In the case of silicon, this dry etching is performed using a gas such as CF4.

Following dry etching, wet etching (using a mixed solution of nitric acid, iodine and glacial acetic acid in this method) is performed to etch the semiconductor substrate 1 and form etching grooves 4. Thereafter, the wax mask 2 is removed using an organic solvent such as trichlene to form a mesa structure as shown in FIG. 1(a).

〔Effect of the invention〕

As described above, the present invention has the effect of improving yield and reducing electrical layer defects by forming a mesa region with high precision and a smooth shape.

[Brief explanation of the drawing]

FIGS. 1(a) to 1(d) are cross-sectional views of each manufacturing process shown to explain a manufacturing method according to an embodiment of the present invention. 1...Semiconductor substrate, 2...Photoresist 1-or protection wax 2+...Photoresist selection window, 3...Mesa groove, 4...・
...Mesa groove after wet etching. .

Claims (1)

[Claims] A mesa groove is formed on a semiconductor substrate using a dry etching method,
1. A method for manufacturing a semiconductor device, characterized in that finishing is then performed using a wet method.