JPH02210819A - Manufacture of soi substrate - Google Patents

Abstract

PURPOSE:To obtain a high quality SOI substrate free of exfoliation by directly or indirectly shielding the part where a base insulating film has a step-difference and exfoliation is apt to happen, with a light shielding film of high melting point metal or high melting point metal compound which does not transmit energy beam, and then projecting the energy beam. CONSTITUTION:When a poly Si film 3 on an insulating film 2 is irradiated with energy beam 4, the part is shielded with a light shielding film 5 which does not transmit the energy beam 4, in the case where the base insulating film 2 has a step-difference, and a part apt to exfoliate because of the difference of thermal conductivities between a substrate 1 and the insulating film 2 exists. That is, the poly Si film 3 is directly coated with the light shielding film 5 of high melting point metal or high melting point metal compound which does not transmit energy beam 4, or the light shielding mask 5 is formed on a mask substrate and then used as a mask by patterning. Thereby, the region apt to exfoliate is not irradiated with the energy beam 4, so that an excellent SOI substrate free from exfoliation can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] The present invention relates to a method for manufacturing a single crystal semiconductor substrate for a Sol structure semiconductor device, which is expected to be a next-generation technology in the semiconductor industry.

Only the part of the 501 substrate to be made into an element, or

The purpose is to manufacture good SOI substrates by irradiating energy beams while avoiding parts that are likely to peel off.

An insulating film and a polycrystalline silicon film are sequentially formed on a substrate, and when the polycrystalline silicon film is irradiated with energy,
A portion of the polycrystalline silicon film provided on the boundary between the substrate surface and the insulating film.

That energy? By shielding the team with a light-shielding film that does not transmit it,
It is constructed by irradiating the energy beam to recrystallize the polycrystalline silicon to form a silicon film.

[Industrial application field]

The present invention is a technology that is expected to become a next-generation technology in the semiconductor industry.
The present invention relates to a method for manufacturing a single-crystal semiconductor substrate for a semiconductor device having an ator) structure.

Semiconductor devices with an SOI structure have excellent high-temperature and high-speed operation and radiation resistance characteristics, but such semiconductor devices with an SOI structure are made using the highest possible quality of silicon (Si).
It is desired to form a single crystal on an insulating film.

[Conventional technology]

In conventional techniques for creating Sol substrates.

As shown in FIG. 4, after bonding a first substrate 20 and a second substrate 21 with an insulating film 19 interposed therebetween,
The first method is to thinly shave the layer 1 and stack an epitaxial film 22 to form an element forming layer.

As shown in FIG. 5(a), a polycrystalline silicon (poly-Si) film 25 is grown on an insulating film 24 on a substrate 23. As shown in FIG.

Direct irradiation with an energy beam 26 such as a laser.

There is a second method in which the poly-Si film 25 is replaced with the Si film 27.

However, both methods have problems in terms of quality and throughput, and there are many points that need to be improved before they can be used industrially.

[Problem to be solved by the invention]

For example, in the second method, as shown in FIG. 5(b), 3
1. When forming a silicon dioxide (SiO□) film 29 on a substrate 28 and irradiating an energy beam 31 to a poly-Si film 30 laminated thereon to form an S3 film 32, the structure of the base film is 2, for example, Sing. When the energy beam 31 hits a portion of the film 29, such as the film installation 9, the heat generated when the energy beam is irradiated causes damage to the SiO□ film 29.
A problem occurred in that the three films 30 were peeled off.

The reason for this is that the thermal conductivity of the Si0g film and Si are significantly different.

Due to the high thermal conductivity of Si, in the thin part of the Si film, heat dissipates to the underlying St substrate, preventing the poly-Si film from reaching a high temperature, and recrystallization of the poly-Si on the thin oxide film. It becomes difficult to proceed. Therefore, a phenomenon occurs in which the poly-Si film is peeled off from the SiO2 film due to the difference in stress with the part to be recrystallized or the large step difference in the oxide film or the like.

Once this peeling occurs, the peeling develops in the traveling direction as the energy beam advances, resulting in continuous peeling and progressing to the element forming region of the recrystallized St single crystal.

The present invention avoids such areas that include areas that are easy to peel off, or conversely, selects only the areas to be converted into SiO□iO□ elements and irradiates them with an energy beam.
The purpose is to obtain a high quality 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 substrate, 2 is an insulating film, and 3 is a poly 5ill.
i, 4 is an energy beam, 5 is a light shielding film that does not transmit the energy beam, 6 is a Si film, 7 is a movable stage,
8 is a heater.

As shown in FIG. 1, an insulating film 2 is formed on a substrate 1, and a poly-Si film 3 is further formed on the insulating film 2.

The substrate 1 is set on a movable stage 7, heated by a built-in heater 8, and moved back and forth 9 and left and right so that the energy beam 4 is irradiated to a predetermined location.

When the poly-Si film 3 on the insulating film 2 is irradiated with an energy beam, there are nine steps in the underlying insulating film 2.

In addition, if there is a structure where the substrate 1 and the insulating film 2 have significantly different thermal conductivities and are easily peeled off, use a light shield that does not transmit the energy beam to prevent the energy beam 4 from hitting and causing peeling. The membrane 5 shields that part.

The shielding method is to directly cover the poly-Si film 3 with a light shielding film 5 made of a high melting point metal or a high melting point metal compound that does not transmit the energy beam, or to directly cover the poly-Si film 3.

After forming the light shielding film 5 on the mask substrate, patterning is performed,
Use as a mask.

[Effect]

In the present invention, since the energy beam is not irradiated to areas where the underlying insulating film has a step and is likely to peel off, it is possible to create a high-quality SOI substrate that does not peel off.

〔Example〕

Two embodiments of the present invention are shown in FIGS. 2 and 3.

In the figure, 9 is a Si substrate, 10 is a 5iO1 film, 11
12 is a poly-Si film, 12 is a SiO□ film, 13 is a Si3N film, 14 is a tungsten (W) film, 15 is an Ar ion laser beam, 16 is a Si film, 17 is a quartz mask substrate, and 18 is a TiN film. be.

As shown in FIG. 2, it was deposited on a Si substrate 9 using the CVD method.

Sing film 10 is applied to 1,000 people, then S (not shown)
After sequentially forming Si, N, and Si3N4 films to a thickness of 1,000 nm, the Si3N4 film is patterned. Next, Sin
G film lO was formed to a thickness of 1.5 μm by thermal oxidation method, and S
After removing the i3N4 film, poly-Si was deposited using the CVD method.
The membrane 11 is laminated to a thickness of 5,000 layers.

Furthermore, by CVD method, 3
00 5i02 membrane 12 and 1, 000 Si3N,
A film 13 is sequentially formed to serve as a cap layer.

The first method of the embodiment is to remove the Si3N4 film 1 on the surface of the substrate 9.
3, a W film 14, which is a high-melting point metal, is formed to a thickness of 5,000 mm by sputtering, so that the W film 14 covers the stepped portion of the SiO□ film on the head that is easy to peel off. Buttering.

The substrate 9 is set on a movable stage and heated by a built-in heater.

Then, an Ar ion laser beam 15 was used as the energy beam, the laser output was IOW, and the scanning speed was 10 cm.
When the surface of the substrate 9 is irradiated while scanning under the condition of /win, the Si film 11 on the SiO□ film 10 main 10
is melted and recrystallized to form the St film 16, but W
The laser beam 15 is reflected in the portion shielded by the film 14 and does not reach the poly-Si film 11.
It will remain intact and will not peel off from that area.

The second method is similar to the above, as shown in Figure 3.
After forming Si, N, and up to the film 13 on the Si substrate 9.

A titanium nitride (TiN) film 18 as a high melting point metal compound is formed on a mask substrate 17 made of quartz to a thickness of 5,000 wafers by sputtering and patterned.

The parts of the poly-Si film 11 that are likely to peel off when irradiated with an energy beam are covered with patterned Ti on the mask substrate 17.
The St film 16 is formed by shielding with the N film 18 and irradiating with the Ar ion laser beam 15 while scanning.

W, Ti are used as light shielding films that do not transmit energy beams.
In addition to N, molybdenum (Mo), tantalum (Ta),
Chromium oxide (Crt(h), etc.) can be used.

〔Effect of the invention〕

According to the present invention, there is a step in the underlying insulating film.

Moreover, the thermal conductivity of the substrate and the insulating film are significantly different.

Parts that are prone to peeling are directly or indirectly shielded with a light-shielding film that does not transmit energy beams, such as high-melting point metals or high-melting point metal compounds, and the energy beam is not irradiated, making it possible to use high-quality SO substrates that do not peel off. You can get a hump.

FIG. 4 shows a conventional example (part 1).

Figure 5 is a conventional example (part 2) It is.

In fig.

■ is the substrate, 2 is the insulating film.

3 is a poly-Si film, 4 is an energy beam.

5 is a light shielding film, and 6 is a Si film.

7 is a movable stage, 8 is a heater 9 is a Si substrate, 10 is a 5i02 film.

11 is a poly-Si film, and 12 is a SiO□ film.

13 is a Si2N4 film, and 14 is a W film.

I5 is an Ar ion laser beam.

16 is a Si film, and 17 is a mask substrate.

18 is a TiN film

[Brief explanation of the drawing]

FIG. 1 is a diagram explaining the principle of the present invention. FIG. 2 shows an embodiment (part 1) of the present invention. FIG. 3 shows an embodiment (part 2) of the present invention. At the end of F, Ming Principles Explanation Team Figure 1, Example of Honju Akime Fruit Color (Sono υ Man 2 Figure Ji K Tei-Sun Moon Fruit) 1! Itari (2)M
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Claims (1)

[Claims] An insulating film (2) and a polycrystalline silicon film (3) are formed on the substrate (1).
) are sequentially formed on the polycrystalline silicon film (3), and when the energy beam (4) is irradiated on the polycrystalline silicon film (3), the polycrystalline silicon film (3) is A portion of the polycrystalline silicon film (3) is exposed to the energy beam (4).
An SOI substrate characterized in that the polycrystalline silicon (3) is recrystallized to form a silicon film (6) by shielding it with a light shielding film (5) that does not transmit the energy beam (4) and irradiating the energy beam (4). manufacturing method.