JPH0223629A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To shorten the production time, and to polish a semiconductor substrate in uniform thickness by laminating an silicon substrate and a support substrate isolated by a dielectric. CONSTITUTION:An silicon dioxide film region 2 as an annular field insulating film is formed under the surface of an n-type silicon sub strate 1. An silicon dioxide laminated film 3 is shaped onto the surface of the n-type silicon substrate 1, and the surface is flatten ed through polishing. An silicon support substrate 4, to the surface of which hydrophilic treatment is executed and the type of an impurity of which is not specified, is prepared, fast stuck to the n-type silicon substrate 1, and silanol-joined. The rear of the n-type silicon substrate 1 is polished, the silicon dioxide film region 2 is exposed, and an element forming region 1a surrounded by the silicon dioxide film region 2 is shaped. An impurity is introduced to the ground surface of the n-type silicon substrate 1 and p layers 5, 5 in desired depth are formed, and an n<+> layer 7 is shaped to the p layer 6. A gate electrode G is formed onto the p layer 6, all anode electrode A to the p layer 5 and a cathode electrode C onto the n<+> layer 7 respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a semiconductor device, and particularly to a method of manufacturing a semiconductor device using a dielectric isolation structure.

[Conventional technology]

Conventionally, as a method for manufacturing a semiconductor device using a dielectric separation method, a method using a polycrystalline silicon layer as a support substrate has been known, and this technology is, for example, developed by N.C.
Research and Development (NECRe5erch)
& Deve! opment) Volume 57, 1980
Published in 2013, page 39.

FIGS. 3(a) to 3(d) are cross-sectional views of a semiconductor chip shown in order of steps to explain an example of a conventional method for manufacturing a semiconductor device.

First, as shown in FIG. 3(a), an n-type silicon substrate 1
After selectively etching 1 to form a layer 10 for element isolation, the surface is thermally oxidized to form an oxide film 12.
form a.

Next, as shown in FIG. 3(b), a polycrystalline silicon layer 1 is formed on the surface of the silicon dioxide film 12a in which the groove 10a is formed.
3 is deposited to a thickness of several hundred μm to fill the armature 10a.

Next, as shown in FIG. 3C, using the polycrystalline silicon layer 13 as a support substrate, the back surface of the semiconductor substrate 11 is polished away to form a single-crystal silicon island element formation region 11a.

Next, as shown in FIG. 3(d), the element formation region 11a
By forming a thyristor 8a having an anode A, a gate G, and a cathode C, a semiconductor device is completed.

[Problem to be solved by the invention]

In the conventional semiconductor device manufacturing method described above, it takes a lot of time and money to deposit several hundred micrometers of polycrystalline silicon layer used as a supporting substrate, and the polycrystalline silicon layer does not have a uniform thickness. Furthermore, it is not possible to polish a semiconductor substrate made of single crystal silicon to a uniform thickness because the polycrystalline silicon layer grows on the opposite side of the growth surface during the process of growing the polycrystalline silicon layer. There were many problems.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a semiconductor device that reduces manufacturing time and allows a semiconductor substrate to be polished to a uniform thickness.

[Means to solve the problem]

A first method for manufacturing a semiconductor device of the present invention includes: (A) forming a field insulating film region from the surface surrounding an element formation region on one principal surface of the semiconductor substrate; (B) forming a field insulating film region from the surface of the semiconductor substrate and the a step of forming an insulating film on the surface of the field insulating film region; (C) a step of closely adhering a semiconductor support substrate to the surface of the insulating film and performing heat treatment to form a laminated substrate; (D) a step of forming a bonded substrate on the surface of the semiconductor substrate; The method includes the step of polishing the main surface to expose the field insulating film region and forming an island-shaped element formation region.

A second method for manufacturing a semiconductor device of the present invention includes a step of forming a stack of an insulating film and a polycrystalline silicon layer on the surface of the semiconductor substrate and the surface of the field insulating film region, in place of the above item (B). It is composed of:

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1(a) to 1(e) are cross-sectional views of a semiconductor chip shown in order of steps for explaining a first embodiment of the present invention.

First, as shown in FIG. 1(a), an n-type silicon substrate 1
A silicon dioxide film region 2, which will become an annular field insulating film, is formed below the surface of the silicon substrate by a local thermal oxidation method surrounding the element formation region, or by a CVD method after locally etching the silicon substrate.

Next, as shown in FIG. 1(b), a silicon nitride silicon dioxide laminated film 3 is formed on the surface of the n-type silicon substrate 1,
The surface is made flat by polishing.

Next, a silicon support substrate 4 whose surface has been subjected to hydrophilic treatment and whose impurity type is not specified is prepared, and brought into close contact with the n-type silicon substrate 1 to perform silanol bonding.

The hydrophilic treatment is a treatment for forming an oxide film on the wafer surface, and is performed by thermally oxidizing the surface of the silicon substrate 4 or immersing it in peroxide water.

Silanol bonding is a process in which the wafer surfaces are brought into close contact with each other and heat treated at 1000°C, for example, so that the hydroxyl groups on the wafer surface become H2O through the heat treatment, causing dehydration and condensation, resulting in the bonding of the wafers.

This method is, for example, I.E.I.E.

International, Electron, Device Meeting (IEEE, International Elec)
tron DeviceMeeting) Technical Digest,
1985, pp. 684-687.

Next, as shown in FIG. 1(d), an n-type silicon substrate 1
The back surface of the silicon dioxide film region 2 is polished to expose the silicon dioxide film region 2, thereby forming an element formation region 1a surrounded by the silicon dioxide film region 2.

Since this polishing method uses an amine aqueous solution as the chemical solution and does not process the silicon dioxide film region 2 at all, the polishing process can be easily stopped at the surface of the silicon dioxide film region 2.

Next, as shown in FIG. 1(e), an n-type silicon substrate 1
Impurities are introduced into the polished surface to form two layers 5 and 6 of a desired depth, and an N+ layer 7 is further formed on the second layer 6.

Next, a gate electrode G is formed on the second layer 6, an anode electrode A is formed on the P layer 5, and an upper cathode electrode C is formed on the N+ layer, thereby completing a dielectrically isolated semiconductor device.

FIGS. 2(a) to 2(e) are cross-sectional views of a semiconductor chip shown in order of steps for explaining a second embodiment of the present invention.

First, as shown in FIG. 2(a), a silicon dioxide film region 2 is formed locally under the surface of an n-type silicon substrate 1 in the same process as in the first embodiment.

Next, as shown in FIG. 2(b), a silicon dioxide film 3a is formed on the surface of the n-type silicon substrate 1, and a polycrystalline silicon layer 9 is further formed on the surface by the CVD method.

Next, as shown in FIG. 2(c), a silicon support substrate 4 having a hydrophilic surface is brought into close contact with the polycrystalline silicon layer 5, and silanol bonding is performed.

Hereinafter, as shown in FIGS. 2(d) and (e), the above-mentioned first
The thyristor 8 is formed in the element formation region 1a in the same process as in the embodiments (d) and (e).

In this embodiment, the polycrystalline silicon layer 5 can easily be polished to a highly flat surface, which has the effect of facilitating bonding to the support substrate 4.

As described above, by using the silicon supporting substrate 4 in the first and second embodiments, it is not necessary to deposit a polycrystalline silicon layer as in the conventional method, and the back surface of the n-type silicon substrate 1 can be made more uniform. It becomes possible to polish.

In the first and second embodiments described above, a case was described in which a citristor was manufactured in the element formation region 1a, but the semiconductor element to be formed is not limited to that. It can be similarly applied to the manufacture of bipolar transistor integrated circuits.

[Effects of the Invention] As explained above, the present invention can be easily formed by laminating a silicon substrate and a support substrate separated by a dielectric material, and can be easily formed by depositing a polycrystalline silicon layer as in the conventional method. Since this is no longer necessary, manufacturing time is shortened, and the thickness of the dielectrically isolated silicon region can be formed uniformly. It has the effect of being controllable.

[Brief explanation of the drawing]

FIGS. 1(a) to (e) are cross-sectional views of a semiconductor chip shown in the order of steps for explaining the first embodiment of the present invention, and FIGS. A cross-sectional view of the semiconductor chip shown in FIG.
1A to 1D are cross-sectional views of a semiconductor chip shown in the order of steps for explaining an example of a conventional method for manufacturing a semiconductor device. 1... N-type silicon plate, 1a... Element formation area,
2... Silicon dioxide film region, 3... Lamination of silicon nitride film and silicon dioxide film, 4... Silicon support substrate, 5... P layer, 7... N+ layer, 8... Thyristor , 9... polycrystalline silicon layer.

Claims (1)

[Claims] 1. (A) forming a field insulating film region from the surface surrounding an element formation region on one main surface of the semiconductor substrate; (B) forming a field insulating film region on the surface of the semiconductor substrate and the field insulating film region; a step of forming an insulating film on the surface; (C) a step of closely adhering a semiconductor support substrate to the surface of the insulating film and heat-treating it to form a laminated substrate; (D) polishing the other main surface of the semiconductor substrate. A method of manufacturing a semiconductor device, comprising: exposing the field insulating film region to form an island-shaped element formation region. 2. A semiconductor device characterized by including a step of forming a laminated layer of an insulating film and a polycrystalline silicon layer on the surface of the semiconductor substrate and the surface of the field insulating film region in place of item (B) of claim 1. manufacturing method.