JPH01246844A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent an abnormal form from occurring at the end parts of a LOCOS isolation region by a method wherein a CVDSiO2 film is buried in grooves in the surface of a substrate to form trench isolation parts and the LOCOS isolation region is formed in a large area of the substrate surface. CONSTITUTION:Grooves are provided in the surface of an Si substrate 1 and after a thermal oxide SiO2 film 2 (1) is formed in the grooves, a CVDSiO2 film is formed on the whole surface and that film is heat-treated to form a buried glass layer 3 in the grooves. After that, the glass layer on the surface is removed to form trench isolation parts 4. Then, a thermal oxide SiO2 film 5 (2) and an Si3N4 film 6 are provided at an element part 9 and moreover, a LOCOS SiO2 film 8 is provided on the large area of the substrate surface by a thermal oxidation and after a LOCOS isolation region is formed, the films 5 and 6 are removed to make Si appear at the part 9. Thereby, no abnormal form appears at the end parts of the LOCOS isolation region and a semiconductor device can be manufactured by a simple process.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a semiconductor device, and relates to a device isolation method using a dielectric material. As an element isolation method, there was a dielectric isolation method using trench isolation.

[Problem to be Solved by the Invention 1] However, according to the above-mentioned prior art, trench isolation alone cannot be applied to integrated circuit devices that require large-area isolation areas (for example, pads and wiring areas). There was a problem that I couldn't do. Therefore,
Naturally, trench isolation and LOGOS
It is possible that isolation is used in combination, but in this case as well, an abnormality may occur in the shape of the end of the isolation part of LOGOS isolation, for example, an extremely thin groove may be formed at the end of the LOCOS isolation part. There was a problem in that in order to fill in the narrow trenches, the same process as trench isolation formation had to be performed again.

The present invention solves the problems of the prior art and
By combining isolation and LOGOS isolation, it is possible to manufacture thin isolation and isolation in areas that require a large area without creating abnormal shapes even at the edges of LOGOS isolation, and with a simple process. The purpose is to provide a method that can be used.

[Means for Solving the Problems] In order to solve the above problems, the present invention relates to a method for manufacturing a semiconductor device, in which a groove (trench) is formed from the surface of a semiconductor substrate by dry etching, and a CVD5
After forming a dielectric element isolation region by so-called trench isolation, which is filled with iO, a phosphorous glass film, etc., an isolation region by so-called LOGOS is formed over a large area of the semiconductor substrate surface where an isolation region is required. take measures to do so.

[Example] Hereinafter, the present invention will be explained in detail with reference to Examples.

FIG. 1 shows an embodiment of the present invention in the order of steps. That is, (a) a thin groove (trench) is formed on the surface of the Si substrate l by dry etching, and a thermally oxidized SiOx film (1
) 2 on the entire surface, for example, a CVD Si Ox film is formed on the entire surface, or a CVD phosphorous glass film is formed and then heat treated to form an embedded glass 3 in the trench, and these on the surface are removed. By removing the glass layer by etching back, the trench isolation part 4 can be formed. (b) Thermal oxidation SiO2 film (2) and CV D +, m J
: 6si sNa film 6 is formed, and the element portions are thermally oxidized 5iO- films (2) 5 and 5iiN4 by photo-etching.
It is removed leaving the film 6 behind. These remaining film ends are normally formed inside the trench isolation section 4, but as shown in the overlap section 7, they may be formed slightly protruding from the S1 surface.

Next, (c) a LOCOS SiO2 film 8 is formed in a large area where isolation is required by thermal oxidation, and the S
By removing the i s Na film 6 and the thermally oxidized 5iOz film (2), Si can be made to appear in the element portion 9. Furthermore, in the overlap portion 7, as shown in the bird's peak portion lO, Si can be exposed. , the end of LOGO3 is formed in a shape different from the shape that appears in the case of the LOCOS SiO2 film 8 extending from the part where the end of the 5isN4 film 6 is formed in the trench isolation part 4. However, in a relatively large isolation region, there is no practical problem even if the bird's peak portion IO appears.

The present invention applies not only to Si substrates but also to so-called SOI (S1 single crystal film substrates on insulators or insulating films).
Needless to say, the present invention can also be applied to a silicon on inductor structure.

[Effects of the Invention] According to the present invention, in a method of manufacturing a semiconductor device, by combining trench isolation and LOGOS isolation 3, thin isolation and isolation gin in a portion requiring a large area can be reduced to abnormalities at the ends of LOCOS isolation. This has the advantage that it can be easily carried out in a simple process without creating a strange shape.

[Brief explanation of the drawing]

FIGS. 1(a) to 1(c) show an embodiment of the present invention in the order of manufacturing steps. 1...Si substrate 2...Thermal oxidation 5iOz film (1) 3...Embedded glass 4...Trench isolation part 5...Thermal oxidation 5iOz film (2) 6...S i x N4 film 7...Overlap part 8...LOCO3SiO□ film 9...Element part 10...Birds peak part and above Applicant Seiko Epson Corporation

Claims (1)

[Claims] Grooves (
After forming a dielectric element isolation region by so-called trench isolation, in which a CVDSiO_2 film, a phosphorous glass film, etc. is embedded in the trench, a large area of the semiconductor substrate surface requires an isolation region. The so-called LOCOS (
1. A method for manufacturing a semiconductor device, comprising forming an isolation region using a local oxidation structure.