JPH0582511A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain the final protective film having an excellent film condition, and to provide a semiconductor device in which the safety of the inside semiconductor element can be protected. CONSTITUTION:After a field oxide film 12 has been formed on a semiconductor substrate 11, a lower layer insulating film 13 is formed with its tip slightly staggering from the field oxide film 12, an upper layer of insulating film 14 is formed thereon with its tip staggering from the tip of the lower layer of insulating film 13, and the final protective film 15 is formed thereon staggering its tip.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor element capable of completely protecting an internal element by obtaining a good state of a final protective film, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, when a plurality of chips are manufactured in a wafer, it is common to form scribe lines so that the chips can be easily divided. This scribe line is removed so that the gate electrode layer and the wiring layer do not cause a short circuit later, and the insulating film layer also does not cause cracks or the like when the chip is cut out and deteriorate the internal elements. The portions necessary for cutting are removed at the time of etching each layer.

FIG. 2 is a sectional view of a conventional semiconductor device.
Reference numeral 21 in the figure denotes a semiconductor substrate. After forming a field oxide film 22 on the semiconductor substrate 21, a first insulating film 23,
After the second field oxide film 24 is sequentially formed so as to be positioned on the inner side by removing the portion necessary for cutting out by etching, the final protective film 25 is formed.

At this time, as shown in FIG. 2, the tips of the respective insulating layers of the first insulating film 23 and the second insulating film 24 are shifted inward, and the final protective film 25 is moved to the outermost side, so that the entire chip is formed. The structure is usually covered.

This is because when the tips of the insulating layers are aligned, the step 26 becomes steep as shown in the circle A1 in FIG.
This is to prevent the final protective film 25 from being completely covered and causing deterioration of the device due to intrusion of water or the like from here.

[0006]

However, in the structure of the semiconductor device as shown in FIG. 2, when the second insulating film 24 in the upper layer is removed by etching, the first insulating film in the lower layer is overetched. 23 was also removed, and in the extreme case, a step as shown in the circle A2 of FIG. 4 was generated, and the shape was the same as that of the example of FIG. 3, and a satisfactory final protective film 25 could not be formed.

This is because the insulating layer is generally an oxide film or the oxide film is doped with impurities (phosphorus, boron, etc.), and the selection ratio between each insulating film and the semiconductor substrate 21 during etching is sufficient. This is because the scribe line is a wide region ranging from several tens to several hundreds of μm, and etching progresses faster than the inside.

The invention of claim 1 solves the problem that the state of the final protective film is deteriorated due to the deterioration of the step shape at the scribe line among the problems of the prior art. An element is provided.

According to the second aspect of the present invention, among the problems of the prior art, the selection ratio at the time of etching by doping the oxide forming the first and second insulating films with impurities is sufficient. The present invention provides a method for manufacturing a semiconductor device, which solves the problem that etching proceeds faster than inside.

[0010]

According to a first aspect of the present invention, in a semiconductor element, a plurality of insulating films are provided so that the upper layer covers the lower layer by shifting the tip.

According to a second aspect of the present invention, in the method of manufacturing a semiconductor element, a step of shifting the tip to completely cover the lower insulating film with the upper insulating film when forming the upper insulating film on the lower insulating film is performed. It was introduced.

[0012]

According to the invention of claim 1, since the semiconductor element is configured as described above, the lower insulating film covers the upper insulating film, so that a sufficient selection ratio between the insulating film and the substrate can be obtained, and etching can be performed. There is no time lag and the state of the final protective film is good, so that the above problems can be eliminated.

According to the second aspect of the present invention, since the steps as described above are introduced in the method of manufacturing a semiconductor element, the insulating film and the substrate can be sufficiently selected, and the final protective film is coated. Also has better coverage.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a semiconductor device and a method of manufacturing the same according to the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a semiconductor device of the present invention obtained by the manufacturing method of the present invention.

As shown in FIG. 1, after the field oxide film 12 is formed on the semiconductor substrate 11, the lower first insulating film 13 is formed. The first insulating film 13 is located outside the lower field oxide film 12 by several μm.

A second insulating film 14 is formed on the first insulating film 13.
To form. At this time, the second insulating film 14 is replaced by the first insulating film 13
It is located outside by several μm.

Then, the final protective film 1 is formed on the second insulating film 14.
5 is formed, the final protective film 15 has a structure that covers the entire surface.

By adopting such a structure, when the final protective film 15 is formed, the tips of the respective insulating layers, that is, the first insulating film 13 and the second insulating film 14 are displaced by several μm. , It has a gentle shape, does not have a step like the conventional semiconductor element shown in FIG. 3, a good film state is obtained, and the second insulating film 14 is formed when the upper second insulating film 14 is etched. Even if the etching of the film 14 is completed faster than the inside, the semiconductor substrate 11 is exposed to the etching atmosphere, so that a high selection ratio (about 5 times) with respect to the second insulating film 14 can be obtained.

For this reason, so-called hollowing due to overetching does not occur, and the shape as shown in FIG. 1 is obtained, and the coating state of the final protective film is not deteriorated. In the present embodiment, the insulating film has a two-layer structure, but the present invention is not limited to this, and even if the insulating film is composed of three or more layers, each insulating film is a lower layer film and an upper layer film in order. The same effect can be obtained if the structure is used.

[0020]

As described above in detail, the first aspect of the present invention is provided.
According to the invention, since the upper insulating film is shifted in its tip so as to cover the lower insulating film, it is possible to always obtain a good film state of the final protective film without causing egress during overetching. It will be possible. Therefore, it is possible to realize a semiconductor element that is resistant to intrusion of water and the like.

According to the second aspect of the present invention, after the lower insulating film is formed on the semiconductor substrate and the tip of the upper insulating film is shifted, the final protective film is shifted on the upper insulating film. Since it is formed, the etching is performed based on the high selection ratio between the substrate and the insulating film, and it is possible to always obtain a good final protective film without causing an undercut at the time of overetching. The element can be completely protected.

[Brief description of drawings]

FIG. 1 is a sectional view showing the configuration of an embodiment of a semiconductor device of the present invention.

FIG. 2 is a sectional view of a conventional semiconductor device.

FIG. 3 is a cross-sectional view for explaining the coverage of each insulating layer of a conventional semiconductor device.

FIG. 4 is a cross-sectional view for explaining the coverage of each insulating layer of a conventional semiconductor element.

[Explanation of symbols]

 11 semiconductor substrate 12 field oxide film 13 first insulating film 14 second insulating film 15 final protective film

Claims (2)

[Claims] 1. A semiconductor device is formed on a semiconductor substrate via a field oxide film, and outside the region of the field oxide film,
A lower insulating film having a region in contact with the semiconductor substrate, and an upper insulating film having a region in contact with the semiconductor substrate, formed on the lower insulating film, outside the region of the lower insulating film, A semiconductor device comprising: a final protective film formed on an upper insulating film and having a region outside the region of the upper insulating film and in contact with the semiconductor substrate. 2. A step of forming a field oxide film on a semiconductor substrate and then forming a lower insulating film by shifting the tip of the field oxide film from the tip of the field oxide film, and insulating the lower layer on the lower insulating film. A step of forming an upper insulating film by displacing the tip from the tip of the film, and a step of forming a final protective film on the upper insulating film by displacing the tip from the tip of the upper insulating film Manufacturing method of device.