JPS60167439A - Manufacture of complementary dielectric isolation substrate - Google Patents

Abstract

PURPOSE:To enable easy manufacture of the titled substrate having good single crystal islands by preventing excess of polishing by polishing the Si surface produced by thick epitaxial growth of Si single crystals, grown at a wide aperture of an insulation oxide film, as a polishing check pattern. CONSTITUTION:An aperture 1b of large aperture width is bored in an Si oxide film at the part of an n type single crystal island 1a. Next, a p type Si is epitaxially grown thinly, and then oxidized. With the Si oxide film 6 left only on the p type single crystal Si grown at the aperture 1b of the Si oxide film, the other part is removed by photoetching technique. A p type single crystal Si layer 3, a polycrystalline Si layer 4, and a transition region 5 are grown as they are, and a polycrystalline Si 7 grows on the oxide film 6. Then, polishing is carried out; when the polishing advances to the part of the single crystal grown at the aperture 1b of the Si oxide film, a wide single crystal part appears and warns the operator that further polishing imposes the danger of exposing the Si oxide film of the n-island 1.

Description

Detailed Description of the Invention A. Industrial Application Field The invention is a complementary semiconductor substrate having single crystal islands for forming n-type and p-type elements separated from each other by an insulating film on one semiconductor substrate. The present invention relates to a method for manufacturing a type insulating isolation substrate.

Complementary technology dielectric isolation substrates can be manufactured using either p-type silicon substrates or n-type silicon substrates, and the invention also applies regardless of whether silicon substrates of either conductivity type are used. Although you can.

Here, a case 1r using an n-type silicon substrate will be explained. A complementary dielectric isolation substrate using an n-type silicon substrate is
It has an n-island formed by anisotropically etching an n-type silicon substrate, and a p-island formed by epitaxially growing p-type silicon after the anisotropic etching. After epitaxially growing p-type silicon, it is necessary to polish the epitaxially grown surface of the silicon substrate.
This polishing is performed on all the tinic patterns formed on the n-island. A portion of the silicon oxide film on the n-island is opened to expose the single crystal, and when the p-island is formed by epitaxial growth, it is used as a check pattern for all the single crystals that will grow in the opening. Since the check pattern is determined by the width of the aperture, we create check patterns of different heights by changing the aperture width, and use this as a guideline for all polishing to determine which width of the check pattern casing will be visible. A check pattern with a small distance from the n-island, that is, a low definition, has a narrow opening in the silicon oxide film and a narrow width of the silicon grown in that area, so polishing has not reached the check pattern. However, it is difficult to distinguish between single-crystal silicon and polycrystalline silicon, so even if the check pattern appears, it cannot be confirmed and there is a risk of excessive polishing and exposing the silicon oxide film on the n-island. . Once the silicon oxide film is rendered useless by polishing, it is removed by various later etching steps.

The film thickness becomes thinner, and the silicon oxide film becomes useless as a mask when forming the P+ layer on the p-island.

There is a high possibility that acceptor impurities will be introduced into the n-island, and even if an element is later formed on such an n-island, satisfactory characteristics will not be obtained. Therefore, it is necessary to avoid exposing the oxidized rM on the n-island due to excessive polishing.

C1 Purpose of the invention The non-invention is a manufacturing method that makes it possible to overcome the drawback that it is difficult to recognize the check pattern at a small distance from the n-island as described above! I! The purpose is to provide i:.

According to the present invention, anisotropic etching is performed on a base silicon substrate of a -4 voltage type, and then an oxide film for insulation isolation is entirely formed, and the insulation oxide film is removed by photolithography. A wide opening is made in one part, and then a thin layer of silicon of the opposite conductivity type is grown epitaxially, followed by complete oxidation. A complementary dielectric comprising: leaving only an oxide film of the silicon, then epitaxially growing a thick layer of silicon, and then polishing the silicon surface grown thickly and epitaxially using the silicon single crystal grown in the wide opening as a polishing check pattern. A method for manufacturing a separated substrate is obtained.

E, Example Next, let's take a look at examples of non-invention! I will explain.

FIGS. 1A to 1D are cross-sectional views of a work-in-progress board in the order of the manufacturing process to fully explain an embodiment of the present invention. 1st
Figure (al) shows that the n-type silicon substrate 11 is anisotropically etched and then oxidized, and then unnecessary parts of the oxide film are removed by photolithography and the oxide film 2 of the useful parts is removed.
It shows the state where . At this time, n-type single crystal island 1a
An aperture 1b having a large aperture width is formed in the silicon oxide film at a portion indicated by . Next, as shown in the same figure (bl), p-type silicon is grown epitaxially.

5- As a result, p-type nested crystalline silicon layer 3. Polycrystalline silicon layer 4. A transition region 5 made of p-type crystalline silicon containing many crystal defects is formed. Next, the silicon oxide film 6 is left only on the p-type single crystal silicon grown on the open hole part 1bK of the silicon oxide film, and the other parts are removed by oxidation and photolithography, as shown in FIG. Remove. clearly, p
Grow thick silicon epitaxially.

As a result, as shown in fdl in the same figure, the p-type nested crystalline silicon layer 3 and the polycrystalline silicon layer 4% transition region 5 grow to their casings, and the polycrystalline silicon 7 grows on the oxide film 6.・Next, complete polishing is performed - but as the polishing progresses and reaches the single crystal part that has grown in the opening 1b of the silicon oxide film, a wide single crystal part appears, and if the polishing continues any further, n-island 1 Warning that there is a risk of exposing the silicon oxide film. Therefore, polishing is stopped at this point.

This state is fat in FIG.

1. Effects of the Invention As mentioned above, in the method of the present invention, if the width of the opening 1b in the silicon oxide film is made sufficiently large, it is easy to see that the single crystal that has grown in that part appears by polishing. You can check it. If this is used in conjunction with a conventional check pattern, excessive polishing can be prevented, there is no risk of the silicon oxide film on the n-islands being exposed by polishing, and complementary dielectric isolation with good single-crystal islands can be achieved. A substrate can be obtained.

[Brief explanation of drawings]

FIGS. 1 through 1 are cross-sectional views of a work-in-progress board in the order of manufacturing steps to fully explain an embodiment of the present invention. 11...N-type single crystal silicon substrate, 1. la...
...N-type silicon single crystal island, ib...Wide opening in oxide film, 2...Oxide film for insulation isolation, 3...
... p-type silicon single crystal layer, 4 ... polycrystalline silicon layer, 5 ... transition region, 6 ... oxide film on opening single crystal silicon , 7...Opening polycrystalline silicon layer. 7-

Claims (1)

[Claims] Anisotropic etching is performed on a silicon single crystal substrate of one conductivity type, an insulating film for insulation isolation is formed, a wide opening is made in a part of the insulating oxide film by photolithography, and then A thin film of silicon of the opposite conductivity type is grown epitaxially, and then oxidized. Of the oxide film formed by this oxidation, only the oxide film on the single crystal silicon grown in the opening is left, and then a thick silicon layer is grown epitaxially. and then completely polishing the silicon surface grown epitaxially to a large extent as a check pattern for polishing the entire silicon single crystal grown in the wide opening portion.