JPS58168259A - Manufacture of semiconductor integrated circuit device - Google Patents

Abstract

PURPOSE:To isolate elements with each other via a complete filmlike silicon oxidized film by thermally oxidizing an oxygen-added thin silicon film formed in the groove formed on the surface of a silicon substrate, thereby eliminating an air gap presented in the oxygen-added thin silicon film and improper filmlike part. CONSTITUTION:An oxygen added thin silicon film 7 is thermally oxidized in dipped oxidative atmosphere to form a completely filmlike silicon oxidized film 72 having 2 of oxygen composition ratio to silicon. Air gap is compressed due to the volumetric expansion of the case that the film 72 is varied to obtain a completely filmlike property so that the volumetric expansion becomes small amount. Thus, no dislocation of crystal is produced in the silicon substrate 1. Then, the film 72 except the groove is removed by anisotropic etching, thereby forming a silicon oxidized film 73 only in the groove 4, and removing a silicon nitrided film 6 and a silicon oxidized film 5 on an element region 3. A silicon oxidized film 51, a silicon nitrided film 61 and a silicon oxidized film 73 are formed only in the inner surface of the groove 4, these insulators can isolate elements with each other, and the substrate 1 can be exposed on an element region 3.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a semiconductor integrated circuit device, and more particularly to a method for electrically isolating base elements formed in a semiconductor substrate using an insulator.

Conventionally, as a method for finely separating elements, a method is known in which a groove is formed in a predetermined region of a surface layer of a semiconductor substrate, and the inside of the groove is filled with an electrical insulator.

An overview of this separation method is shown in Figures 1 and 2.
m, first, as shown in happy iml, the silyran group @
1. A predetermined area K to separate O element 10 M.

If you keep it as a master with resist etc., it will become a parallel plate electrode type dog! A silicon oxide film 2 is formed using a quenching method (hereinafter referred to as anisotropic etching) to directly etch the etching surface, and then a silicon oxide film 2.
is deposited by a chemical vapor deposition method (hereinafter abbreviated as OVD machine). Thereafter, as shown in Figure 211, a method was used in which the silicon oxide film 21 was removed by anisotropic etching to form a silicon oxide film 21 only inside the trenches, thereby isolating the elements. -ru.

However, in such conventional separation methods, the 31st
As shown in FIG. 1, silicon oxide 22 without voids and a filmy O storm is likely to be formed in the center of the groove during deposition in the silicon oxide metal 1oOVD method.

As shown in Fig. 314, the center 11KIII of the groove after etching is located at the ninth part, which is properly etched compared to the anisotropically etched @Km unfavorable film part.
The main drawback is that it causes cuts.

In order to eliminate the above-mentioned quadratic defect, the present invention deposits an oxygen-doped silicon thin film with an oxygen-to-silicon ratio of less than 2 in a groove layered in a region of a silicon substrate where devices are to be separated. Then, by thermally oxidizing this oxygen-doped silicon thin film to form a silicon oxide film with the above-mentioned oxidation ratio of 20, the oxygen-doped silicon thin film contains 9! Ig
The present invention provides a method for manufacturing a semiconductor integrated circuit device in which elements can be separated by a silicon oxide film of perfect film quality by eliminating portions with poor I and O film quality.

Embodiments of the present invention will be described below with reference to the drawings.

Broom 511PJI Figure 9 is part 1 of the manufacturing method according to the present invention.
1IA11i1 is a partial step cross-sectional view of a rounded inter-element dividing area. First, as shown in Figure 11g5, the conductivity type is P type and carrier #I degree is 1O14~10''
A region K114 is formed in which elements other than the element region 3 above the m-'s* series group I[1 are to be separated. In this case, when forming the grooves 4, patterning is performed on the silicon substrate 1 and a resist is used to resist etching of the silicon oxide film, etc.
Thin film! The silicon aWt may be anisotropically etched using a parallel plate electrode 1i etching apparatus or the like. For example, patterning on WiA silicon base IEI with a thickness of 1.8 aslljlE()■-137
A resist consisting of 0! The reactant gas CCI, F was applied to the above-mentioned Goods Ma etching at a pressure of 50 to 500 siTorr.

By etching the silicon base 41[1] laterally using etching, a concave shape 4 having a thickness of n,5saK is formed.

Next, as shown in III@IIK, in order to improve the interface state of the silicon substrate 1 inside the #$4 and on the element region 3, the substrate temperature was increased to 900 to 1100'' by thermal oxidation.
o4 and f thickness 1200~2ooooim degree.

A silicon oxide film 5 is formed, and then a silicon oxide film 5 is formed on the film by KOvD method or the like at a substrate temperature of 700-1000''C and a thickness of 1B00-2ooo using silane and ammonia as reaction gases.
! A high-grade silicon nitride 1146 is formed as an oxidation-resistant thin film. Then, K as shown in FIG.

In the OVD method, the iop group [11j[700-1000'ol
Silane as reaction residue, 00. ．． A thin layer of oxygen-doped silicon (8i0x, 0 < x < 2) 7 is deposited using H, in which the ratio of oxygen to silicon is less than 2. The film thickness of element-doped silicon is s
4j＠". 9. 1. In the deposition of the acid-doped silicon thin film T, unnecessary film molecules 1 containing voids are formed at the center of #14 at a depth of 11 KMi. ”
7. Ht, □ Ru・ Then, as shown in Figure -8, the 1 m bulk-added silicon □ thin film 7 was thermally oxidized in a moist oxidizing atmosphere at a substrate temperature of 900 to 1100°C, and the oxygen A complete film of silicon oxide 1172 having a composition ratio of 2 is formed. As a result, the voids existing in the poor film quality portion 11 are compressed due to the volume expansion when the thermal oxidation 1 -Cd, oxygen addition 7, 2 thin film T silicon oxidation 11?2. , the poor film quality 71 is improved, and a silicon oxide film 72 with perfect film quality is obtained. t, above 0
No stress is generated in 1, and therefore no crystal defects are generated.

Next, using a reaction sputter etching device, a pressure of 1-100 storr was used, and o'IP4 and H-ho were used as reaction gases. By removing the silicon oxide film T2, a silicon oxide film 13 is formed only inside a $4, and finally by removing the silicon nitride 6 and silicon oxide layer 5 on the element region 3, LIl 14 is formed. A silicon oxide film 51°, a silicon nitride film @1 and a silicon oxide film 13 are formed only directly within the element region 3, and these insulators can isolate the elements. You can be self-sufficient by exposing yourself.

In the above-mentioned nine embodiments, the silicon oxide film 5 and the silicon nitride film 6 as an oxidation-resistant thin film are laminated and formed on the silicon substrate surface including the inside of J114, but the present invention is not limited to this. The above-mentioned silicon oxide film 5.
A suitable oxidation-resistant thin film was selected9, and a silicon substrate was also used.
Of course, various changes can be made, such as using different shapes.

That’s all! As explained, according to Headquarters @, an oxygen-doped silicon thin film is formed inside the container formed on the surface of a silicon substrate, and by thermally oxidizing this oxygen-doped silicon thin film, during the formation of the oxygen-doped silicon thin film, Since it is possible to remove the void in the center of the round groove and the unreliable film part, the groove can be filled with only a perfect silicon oxide film, and
A flat isolation region can be formed. In addition, since the volumetric expansion of the oxygen-doped silicon thin film during the above thermal oxidation is small,
This method has the effect of eliminating crystal defects in the silicon substrate, which occur when polycrystalline silicon is thermally oxidized.

[Brief explanation of the drawing]

FIGS. 1 to 4 are partial process cross-sections 111 of an element isolation section for explaining a conventional example, and FIGS. FIG. 6 is a partial process cross-sectional view of the rounded element isolation section shown in FIG. )...Silicon substrate, 3...Element area, 4...
Siri: 2y group 41 [#IlI picture groove, 5.51...
Silicon oxide film formed by thermal saponification, 6, @1.
...Silicon oxide film, 7..Oxygen 511A silicon thin metal, 71..Unstormy metal part containing voids exclusively in oxygen-added silicon thin film T, 72.73..Oxygen A complete silicon oxide film is formed by thermally saponifying the doped silicon substrate T. Patent applicant: Masaki Yamakawa, agent of Nippon Telegraph and Telephone Public Corporation

Claims (1)

[Claims] A groove is formed in the area where the elements are to be separated on the main surface of the silicon substrate O, and at least the silicon substrate that meets the inside of the groove is leak-tight. A semiconductor integrated circuit comprising forming an additive silicon thin film and converting it into a silicate oxide film having an affinity ratio of 20 (by heat treatment in an oxidizing atmosphere), and creating an isolation region between elements with the silicon oxide film. A method of manufacturing a circuit device.