JPH02219252A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To avoid the oxidation of a part position, and prevent the generation of defects by forming a third semiconductor oxide film on a first semiconductor substrate via a non-oxidizing film, at the time of forming an element isolation region. CONSTITUTION:On a first semiconductor substrate 1, a non-oxidizing film 2 is formed; a first insulating film 3 is formed thereon; a second insulating film 5 is formed on a second semiconductor substrate 4; the first insulating film 3 on the first semiconductor substrate 1 and the second insulating film 6 on the second semiconductor substrate 4 are stuck to each other, thereby forming an SOI substrate. Successively, the second semiconductor substrate 4 is polished up to a necessary thickness, or the first semiconductor substrate 1 is polished up to a necessary thickness. Etching is performed so as to penetrate the second semiconductor substrate 4 polished up to a necessary thickness, the second insulating film 6, and a first insulating film 3, or to use the non- oxidizing film 2 as a stopper for the first semiconductor substrate 1. Thereby, a trench for forming an element isolation region, on the bottom surface of which the non- oxidizing film is exposed, is formed. Next, by oxidation, a third insulating film 7 is formed on the inner wall of the trench. Hence crystal defect can be reduced.

Description

[Detailed description of the invention] 〔overview〕 The present invention uses an insulating layer such as a semiconductor oxide film.

By bonding semiconductor substrates together, elements are formed on the insulating layer. Regarding a method for manufacturing a semiconductor device using the so-called bonding Sol technology.

The purpose is to reduce crystal defects caused by the formation of element isolation regions when bonded SOI substrates are used.

A step of sequentially forming a non-oxidizing film and a first insulating film on a first semiconductor substrate, and a step of forming a second insulating film on a second semiconductor substrate.

bonding the second semiconductor substrate onto the first semiconductor substrate via the second insulating film and the first insulating film; A process of etching a certain amount of the surface opposite to the adhesive surface.

A groove for isolation between elements is formed in the first semiconductor substrate or the second semiconductor substrate that has been etched by a certain amount, and the non-oxidizing film is exposed on the bottom surface. and a step of forming an insulating film.

[Industrial application field]

In the present invention, elements are formed on the insulating layer by bonding semiconductor substrates together via an insulating layer such as a semiconductor oxide film. The present invention relates to a method for manufacturing a semiconductor device using the so-called bonded SOI technology, and in particular to reducing crystal defects caused by the formation of element isolation regions when using an SOI substrate.

Semiconductor integrated circuit devices are also required to be more highly integrated and faster.

For this reason, the development of devices using Sol substrates requires not only miniaturization but also improvements in device performance.

[Conventional technology]

FIG. 3 shows a schematic cross-sectional view of a conventional method for separating elements on a Sol substrate.

In the figure, 27 is the first Si substrate, 28 is the first 34
0g film, 29 is the second Si substrate, 30 is the second 340g
film.

31 is the first epitaxial layer, 32 is the third SiO□
The film 33 is a buried collector layer, 34 is a second epitaxial layer, 35 is a fourth SiO□ film, 36 is a U groove, and 37 is a fifth SiO□ film.

As shown in FIG. 3(a), a first Si substrate 27 is thermally oxidized to form a first SiO□ film 28 on its surface.

As shown in FIG. 3(b), the other second Si substrate 29 is thermally oxidized to grow a second 5i02 film 30 on one surface and patterned.

After forming a first epitaxial layer 31 of Si single crystal thereon, the second Si substrate 29 is surface-treated with nitric acid to form a thin third SiO□ film 32.

Next, as shown in FIG. 3(C), the first Si substrate 27
and second Si substrate 29, respectively, with first oxide film 28 and second SiO□ film 30. and a third 5iO7
They are bonded together with a film 32 interposed therebetween.

As shown in FIG. 3(d), the bonded substrates are attached to the second Si substrate 2 using the second SiO□ film 30 as a stopper.
9 is polished and removed.

As a result, the first epitaxial layer 31 of thin single crystal Si is formed on the insulating layer in the uppermost layer of the first Si substrate 27.

Next, as shown in FIG. 3(e), a buried collector layer 33 is formed by n diffusion into the first epitaxial layer 31, and then an n-type second epitaxial layer 34 is grown on the entire surface.

Subsequently, as shown in FIG. 3(f), a fourth S layer is deposited on the grown second epitaxial layer 34 by the CVD method.
An iO□ film 35 is grown.

Next, as shown in FIG. 3(g), a fourth 5in2 film 3 is formed.
After patterning 5, the first SiO□ film 28 film shape 8
A U-groove 36 for forming an element isolation region is formed as a capper.

Subsequently, as shown in FIG. 3(h), a fifth SiO□ film 37 is formed on the inner wall of the U-groove 36 by thermal oxidation.

At this time, by oxidation heat treatment, the buried collector layer 33 and
In the Si single crystal of the second epitaxial layer 34.

Crystal defects occur.

And a second epitaxial layer 34 which is an element formation region.
Moreover, when a bipolar transistor is formed, the characteristics deteriorate.

As mentioned above, the conventional bonded Sol substrate uses a SiO2 film as an insulating layer.

Therefore, stress was applied to the Si single crystal due to thermal oxidation during subsequent formation of the element isolation region, and crystal defects were generated in the element formation region.

[Problem to be solved by the invention]

Therefore, even if an element is formed, the characteristics of bipolar transistors and the like deteriorate due to the occurrence of crystal defects, resulting in a loss of reliability.

The present invention aims to reduce crystal defects when performing element isolation using a bonded Sol substrate.

[Means to solve the problem]

FIG. 1 is a diagram explaining the principle of the present invention.

In the figure, 1 is a first semiconductor substrate, 2 is a non-oxidizing film,
3 is a first insulating film, 4 is a second semiconductor substrate, 5 is a second insulating film, 6 is a groove for forming an element isolation region, and 7 is a third insulating film.

As shown in FIG. 1(a), a non-oxidizing film 2 is formed on a first semiconductor substrate 1, and a first insulating film 3 is formed thereon.

Further, as shown in FIG. 1(b), a second insulating film 5 is formed on the second semiconductor substrate 4.

Next, as shown in FIG. 1(c), the first semiconductor substrate 1
The first insulating film 3 on the top and the second insulating film 5 on the second semiconductor substrate 4 are bonded together to form a Sol substrate.

Subsequently, as shown in FIG. 1(d), the second semiconductor substrate 4 is polished to a required thickness, or the first semiconductor substrate 1 is polished to a required thickness.

The bottom surface is etched through the second semiconductor substrate 4 polished to a required thickness, the second insulating film 5, and the first insulating film 3, or the first semiconductor substrate 1 is etched using the non-oxidizing film 2 as a stopper. A trench 6 for forming an element isolation region in which the non-oxidizing film is exposed is formed, and then oxidation is performed to form a third insulating film 7 on the inner wall of the trench.

[Effect]

In the present invention, as shown in No. 1119, the third semiconductor oxide film 7 is formed on the first semiconductor substrate X via the non-oxidizing film 2 when forming the element isolation region. That part will not be oxidized.

Therefore, no defects occur.

〔Example〕

FIG. 2 shows schematic cross-sectional views of two embodiments of the present invention in order of steps.

In the figure, 8 is the first Si substrate, 9 is the first 5iOz
10 is a Si3N4 film, 11 is a second SiO□ film, 1
2 is the second Si substrate, 13 is the third 5i02 film, 14 is the first epitaxial layer, 15 is the fourth 5i(h film, 1
6 is a buried collector layer, 17 is a second epitaxial layer,
18 is the fifth Si0g film, 19 is the U groove, 20 is the sixth S
An iO□ film, 21 is poly-Si, 22 is a seventh SiO□ film, and 23 is an An electrode.

In both examples, the first and second Si substrates are p-type <
100 > orientation, mirror-polished Si with resistivity 10Ωcm
Uses wafers.

In the first embodiment, as shown in FIG. 2(a), first, a first Si substrate 8 is thermally oxidized at 1,000''C, and a first SiO□ film 9 is formed to a thickness of 1μ. Then, by the CVD method, an S!
A second 5i02 film 11 is formed to a thickness of 100 mm using C.

As shown in FIG. 2(b), the other second Si substrate 12 was thermally oxidized at 1,000°C to form a third 5iO7 film 13 to a thickness of 5,000 mm. , patterning. After growing a first epitaxial layer 14 of p-type Si with a resistivity of 100 cm to a thickness of 5,000 cm, the second Si base 12 is surface-treated with nitric acid, and a thin epitaxial layer 14 is grown thereon. A fourth StO□ film 15 is formed on the surface.

Next, as shown in FIG. 2(C), the second SiO□ film 11 on the first Si substrate 8 and the fourth SiO□ film 15 on the second Si substrate 12 are aligned. 1,200°C for 30 minutes in a nitrogen gas atmosphere under slight pressure.
Heat for a minute and stick together.

Subsequently, as shown in FIG. 2(d), the bonded substrates are covered with a second SiO film 13 using the third SiO□ film 13 as a stopper.
The base Fi12 is completely removed by polishing.

As a result, the topmost layer of the first Si substrate 8 has a thin first epitaxial layer 14 of Si single crystal formed on the insulating layer.

Furthermore, as shown in FIG. 2(e), this first epitaxial layer 14 is coated with antimony (Sb) at 1,250°C.
A buried collector layer 16 is formed by performing n+ diffusion over the entire surface.

Subsequently, an n-type first epitaxial layer 17 is grown on the surface of the buried collector layer 16 to a thickness of 1 μm by heat treatment at 1050° C. for 5 minutes.

Subsequently, as shown in FIG. 2(f), a fifth 5iQz film 18 is grown to a thickness of 3,000 wafers at 800'C by CVD on the grown second epitaxial layer 17.

Next, a U-groove 19 is formed in the element isolation region by anisotropic etching using the Si, INa film 10 as a stopper, followed by thermal oxidation at 1,000°C for 1 hour.
A sixth SiO□ film 20 is formed on the inner wall of the U-groove 19 to a thickness of 1,000 mm.

Next, as shown in FIG. 2(g), poly 5i21 is
It is grown in the U groove 19 at 0°C to fill the groove.

Thereafter, poly-Si deposited outside the grooves is removed by three polishing steps.

Subsequently, thermal oxidation is performed at 1000°C for 1 hour to grow a seventh 5in2 film 22 on the surface to a thickness of 3000mm.

After this, the second epitaxial layer 1 of the first Si substrate 8 is
In 7, form the Hess region and Emic region using the normal process, and then proceed to! The electrode 23 is patterned to form an element.

A second embodiment is shown in FIG. 2(e). The steps up to the formation of the buried collector layer 16 and the second epitaxial layer 17 are performed in the same steps as in the first embodiment.

Then, as shown in FIG. 2(h), a second 5tJa film 24 is formed on the second epitaxial layer 17 at 800° C. to a thickness of 3,000 yen by CVO method, and then patterned. do.

Subsequently, 3.5μ oxidation is performed using 5iJ411i24 as an oxidation mask. As a result, a fifth SiO□ film 25 is formed for element isolation.

Subsequently, as shown in FIG. 2(i), similar to the first embodiment, in the second epitaxial layer 17, by a normal process,
A base region and an emitter region are formed, and the Al electrode 26 is patterned to form a device.

〔Effect of the invention〕

As described above, according to the present invention, the stress due to volume expansion during element isolation oxidation is mainly influenced only in the lateral direction, and the stress from the bottom surface can be almost ignored, so the occurrence of crystal defects can be reduced. .

[Brief explanation of the drawing]

FIG. 1 is a diagram explaining the principle of the present invention. FIG. 2 is a schematic cross-sectional view of the steps in an embodiment of the present invention. FIG. 3 is an explanatory diagram of a conventional example. In fig. 1 is a first semiconductor substrate, 2 is a non-oxidizing film 3 is a first insulating film, 4 is a second semiconductor substrate 5 is a second insulating film,
6 is the groove. 7 is a third insulating film, and 8 is a first Si substrate. 9 is the first SiO□ film, 10 is the Si3N4 film 11 is the second SiO□ film, 12 is the second Si substrate 13 is the third SiO□ film, and 12 is the second SiO□ film.
The O□ film 14 is the first epitaxial layer. 15 is a fourth 5iO7 film, and 16 is a buried collector layer. 17 is a second epitaxial layer. 18 is the fifth SiO□ film, 19 is the U-groove 20 is the sixth SiO□ film, and 21 is poly-Si. 22 is the seventh SiO□ film, 23 is the electrode 24 is the second 5iJn film, and 25 is the fifth 5iO7 film. 26 ha! electrode ℃

Claims (1)

[Claims] A non-oxidizing film (2) is sequentially formed on the first semiconductor substrate (1).
and a step of forming a first insulating film (3), and a step of forming a second insulating film (5) on the second semiconductor substrate (4), and a step of forming the second insulating film (5) on the second semiconductor substrate (4). a step of adhering onto the first semiconductor substrate (1) via the second insulating film (5) and the first insulating film (3); Second semiconductor substrate (4
) of the first semiconductor substrate (1) or the second semiconductor substrate (4) that has been etched by a certain amount, a non-oxidizing film (2 )
A semiconductor device comprising the steps of: forming a trench (6) for isolation between elements in which is exposed; and then performing oxidation to form a third insulating film (7) in the trench (6). manufacturing method.