JPS58114422A - Manufacture of substrate for semiconductor device - Google Patents

Abstract

PURPOSE:To obtain a substrate appropriate for an MOSFET, etc. by a method wherein, on a single crystal or a polycrystalline substrate, an insulation film having well curb form windows is formed, a thin insulation film is provided in the window, then a polycrystalline or an amorphous Si film having sufficient thickness is deposited over the entire surface, thereafter a laser is scanned, and thus the window is filled with Si. CONSTITUTION:On the single crystal or the polycrystalline Si substrate 11, the insulation film 12 constituted of SiO2 or Si3N4, etc. is adhered, then is selectively etched, thus a plurality of windows 13 are opened, and accordingly a part of the substrate 11 is exposed. Next, a thin insulation film 14 is provided on the exposed surface, and, over the entire surface including it, the polycrystalline or the amorphous Si film 15 is deposited by a CVD method. Thereat, the thickness of the film 15 is one having an amount enough to fill the window 13 when the fusion flow of Si thereafter. Thereafter, the substrate 11 is allowed to increase the temperature up to approx. 500 deg.C, then, while scanning a laser on the film 15 in this state, it is irradiated resulting in the fusion flow, and thus the window 13 is filled. Thus, after an irradiation spot moves, the Si in the window 13 is solidified, and simultaneously changed into single crystals 16A-16C.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to a semiconductor device, and more specifically, to a method for changing light on an amorphous insulating film from polycrystalline silicon to single crystal silicon by laser irradiation. The present invention relates to a method of manufacturing a substrate having a plurality of semiconductor sound device formation regions which are separated and separated by a dielectric material.

(2) Background of the technology Research and development is underway to convert amorphous or polycrystalline thin films into single-crystalline films by laser irradiation and use them in the manufacture of semiconductor devices (for example, Tokuyama and Kurashira).

Miyao: Laser annealing technology where research is rapidly expanding 2. Electronics, June 11, 1979 issue, Yuki 11
Pages 6 to 151, Hirohisa Nibibayashi: Single crystal growth method on amorphous insulating film to realize new LSI 9 Nikkei Electronics, February 18, 1980 issue, pages 82 to 90
(see page).

(3) Prior art and problems The applicant has filed Japanese Patent Application No. 55-98397 and Japanese Patent Application No. 5
No. 6- (filed on September 30, 1981), a semiconductor in which a single crystal region is formed from a non-single crystal material in a recess of an insulator by laser irradiation! ! Propose a manufacturing method for your favorite board.9.

The manufacturing method proposed in Japanese Patent Application No. 1983 was as follows.

#! As shown in Figure 1, 9 base plates 1 (silicon, metal,
A substrate 2 of an insulating layer (silicon dioxide) is formed on a plate (of alumina, high-purity quartz, etc.), and a recess 3 is formed by selectively etching this substrate 2 using a photolithography technique. Next, a polycrystalline silicon film 4 is formed on the entire surface, and a phosphosilicate glass (PEG) layer 5 is formed, although it is not essential.
is formed on top of it. for example.

The thickness of the substrate 2 is 4 if 1μ, the size of the recess is 30×50μ, and the thickness of the substrate 2 at the bottom of the recess is l.

is 0. It is an irises, and the width t between the depressions is 5μ islands.

The thickness t4 of the polycrystalline silicon film 4 is 0.5 to 1 μm.
, and the thickness of the phosphosilicate glass layer is 1 μm.

While heating and maintaining the entire structure at about 500° C. in the state shown in FIG. 1, a continuous wave (CW") laser is scanned and irradiated to melt the polycrystalline silicon film 4, and the molten material accumulates in the recess 3.

After the irradiation is completed due to the movement of the irradiation spot, the melt solidifies in the recess and becomes a single line crystal. The silicon single crystal regions 6A, 6B, and 6C (Fig. 2) thus obtained are I
m! They are surrounded by an edge layer and are dielectrically isolated from each other. Then, by removing the phosphosilicate glass layer 5, the semiconductor device substrate shown in FIG. is made.

A transistor (for example, MOS FET) is placed in the silicon single crystal region of the semiconductor device substrate manufactured in this manner.
If formed on a silicon base plate 1, a faster operating speed can be obtained than an ordinary 42) MOS FET formed on a silicon single crystal substrate (wafer).
The thin insulating layer between the source and drain of T causes a certain amount of parasitic capacitance, which limits the operating speed.

(4) Purpose of the Invention The purpose of the present invention is to improve the above-mentioned conventional substrate for semiconductor devices and to provide a substrate on which a MOS FET can be formed with higher operating speed and lower power consumption. be.

(5) Structure of the Invention The manufacturing method according to the present invention includes the following steps in addition to the conventional method for manufacturing a semiconductor device substrate: A step of forming a second insulating film on the silicon single crystal region and the insulating film.

forming a support layer on the second insulating film, which is the same or different from the second insulating film; and a base plate made of silicon or the like (e.g., a silicon substrate).
A process in which the silicon single crystal region is exposed by etching away.

We will discuss the addition of this as a feature. The exposed surface of this exposed silicon single crystal region is opposite to the conventional exposed surface, and this single crystal region is supported by the second insulating film and the support layer.

(6) Embodiments of the Invention The present invention will be described by way of embodiments suitable for trench penetration with reference to the accompanying drawings.

Figures 3 to 9 are a schematic cross-sectional view and a perspective view of a substrate for explaining each step of the method for manufacturing a semiconductor device substrate according to the present invention. And, Figure 11 shows the MOS FET
FIG. 10 is a schematic cross-sectional view when the structure is formed based on the base shown in FIG. 10;

As shown in FIG. 3, an insulating film 12 of silicon dioxide (or silicon nitride) is formed on a single-crystal or polycrystalline silicon substrate 11. The thickness of the insulating film 12 is 2, for example, 1 μm, and if it is a silicon dioxide film, it can be formed on a silicon substrate by thermal oxidation or chemical vapor deposition (CVD method); If it is a film, it is formed by the CVD method.

Next, the insulating film 12 is selectively etched using a conventional photoetching method to open a window 13 and expose a portion of the silicon substrate 11 (FIG. 4).

Silicon substrate 11 with this insulation 1112
A thin insulating layer 14 is formed on the surface of the exposed portion by thermal oxidation or thermal nitridation treatment (FIG. 5).

Alternatively, the structure shown in FIG. 5 may be obtained by performing controlled etching on the first insulating film 12 in the state shown in FIG. 3, leaving the insulating film 14. A perspective view of the state at this time is shown in FIG. 6, and a large number of windows 13 are formed in the insulating film 12.
The dimensions of 13 are, for example, 20 μll x 20 straws. The thickness of the thin insulating film 14 is 1, for example, 0.1 μm.

Next, a polycrystalline (or amorphous in some cases) silicon film 15
is formed on the entire surface by CVD method (FIG. 7). What is the thickness of this polycrystalline silicon 915?

For example, it is 0.4μ rich. A phosphosilicate glass film (for example, thickness: IJ1m) is deposited on this silicon film 15 by CVD.
It may also be formed by method D (not shown). This glass film acts to suppress heat dissipation and helps create a favorable temperature gradient during single crystallization in the post-processing process.

Obtained silicon substrate) 11t-, N, tba,
While heating and maintaining the temperature at about 500° C., the polycrystalline silicon film 15 is melted by scanning laser irradiation. This irradiation is carried out using, for example, a continuous wave (CW) argon laser with a power of 12 W! ) The scanning speed was 210 cIM/sec and the spot size was 50 μm.

The silicon melted on the insulating film 12 flows into the window 13, and when the irradiation spot moves, it solidifies and becomes a single crystal within the window 13), forming a silicon single crystal region 16A.

16B and 16C (FIG. 8) are formed. If a phosphosilicate glass film is formed, it is removed by etching in the ninth step.

Conventionally, silicon single crystal regions 16A and 16B are used.

Circuit elements such as predetermined transistors and diffused resistors in the 16C are manufactured using known processes.

According to the present invention, another insulating film 17 is then formed on these silicon single crystal regions 16A, 16B, 16C and on the insulating film 12 by chemical vapor deposition (CVD) or vapor deposition. (Figure 9).

This further insulation II (17Fi) is silicon dioxide or silicon nitride and has a thickness of 1, for example 1 to 2 microns. A support layer 18 is formed on this insulating film 17 (FIG. 9). This support layer 18 preferably has a thickness of 100Js or more, and may be made of polycrystalline silicon or resin.Furthermore, the support layer 18 may be composed of an adhesive and a glass (or ceramic) substrate. good.

Next, the silicon substrate 11 is etched away, and the thin/I insulating film 14 is further etched away using an appropriate etching agent (FIG. 10). In this way, silicon single crystal regions 16A and 16B are formed.

16C is surrounded by another insulating film 17 at its bottom and by an insulating layer 12 at its side to achieve complete dielectric isolation, thereby obtaining a semiconductor device substrate having such a single crystal region. .

FIG. 11 shows a case where a MOSFET is formed on this semiconductor device substrate by a known process. Silicon single crystal region 16
A source region and a drain region 21 are formed in B (the same is true for 16A and 16C, but only the region will be explained for convenience), and a gate 23 is provided on the insulating film 22 on the surface of the single crystal region.

Through the window of the insulating film 24 such as phosphosilicate glass, a predetermined electrode is
That is, the source electrode 25. A MOS FET is obtained by forming the gate electrode 26 and the drain electrode 27.

(7) Effects of the invention MOS FET in a silicon single crystal region as described above
The insulating film at the bottom of the MOS FET is much thicker than that of a conventional MOS FET, and the parasitic capacitance of the source and drain is also small.
Therefore, MOSFETs with higher performance than conventional ones, which have faster operating speeds and improved circuit speeds and lower power consumption, can be formed on semiconductor device substrates made using the manufacturing method of this invention. be able to.

[Brief explanation of the drawing]

1 FIA and FIG. 2 are schematic partial cross-sectional views of a rounded board for explaining the conventional manufacturing process of a board for a conductor device, and FIGS. 3 to 11 are for explaining the manufacturing process according to the present invention. FIG. 6 is a partial perspective view of the semiconductor device substrate shown in FIG. 5. FIG. 11... Silicon! Fast rate 12...
Insulating film 13... Window 14... Thin insulating film 15... Polycrystalline silicon film 16A, 16B, 16C... Silicon single crystal region 17... Insulating film 18... Support layer FIG. Figure 2 Figure 3 Figure 7/ Figure 8 Figure 9

Claims (1)

[Claims] 1. The following steps ω~): (7) A step of forming a thick fourth insulating film on a silicon substrate. ←) A step of selectively etching the first insulating film having a thickness of Lf-h to form a predetermined window portion, and forming a structure in which a depressed insulating film is on the substrate within the window. (b) melting the polycrystalline silicon by laser beam irradiation in an amount appropriate to deepen the window (and forming a polycrystalline silicon film over the entire surface); A step in which the polycrystalline silicon in the portion flowing into the window and forming a silicon single crystal region on the thin Vk layer inside the window by the irradiation wave. In a method of manufacturing a substrate for a semiconductor device having a dielectrically isolated silicon single crystal region comprising: The manufacturing method further includes the following steps) to (c): d) forming a second insulating film on the silicon single crystal region and the insulating film. (b) forming a support layer of the same or different quality as the second insulating film on the second insulating film; and (e) etching away the silicon substrate to expose the silicon single crystal region. Process. A method for manufacturing a substrate for a cow conductor cover, comprising: