JPH02267931A - Manufacturing method of semiconductor device - Google Patents

Abstract

PURPOSE:To obtain a single crystal layer excellent in crystallizability in a wide range by a method wherein, when SOI (semiconductor or silicon on insulator) structure is formed by lateral direction solid growth method, the surface temperature at the time of recrystallization is smoothly controlled. CONSTITUTION:By using repeated selective oxidation in which oxidation resistant masks 4, 5 formed in the same region on a substrate 1 are gradually made smaller, abrupt temperature change on the boundary of thickness of an insulating layer 2 is prevented in accordance with the distance further from a seed part 6 in contact with single crystal. That is, when SOI structure is formed by using lateral direction solid growth method, the surface temperature at the time of recrystallization can be smoothly controlled, thereby obtaining a single crystal layer excellent in crystallizability in a wider range.

Description

[Detailed description of the invention] [Summary] SOI (Semiconductor or 5ili
Concerning a method for manufacturing a con on inductor structure.

When forming SO■ structure by lateral solid phase growth method.

Enables smooth temperature control during recrystallization.

The aim is to obtain a single crystal layer with good crystallinity over a wide range.

An insulating layer (2) is deposited on a single crystal substrate (1), an oxidation-resistant first mask pattern (4) is formed on the insulating layer, and the substrate is selectively thermally oxidized to form the first mask pattern. forming an oxidation-resistant second mask pattern (5) on the flat surface of the recess of the insulating layer, selectively thermally oxidizing the substrate, and removing the second mask pattern; The process is repeated until the area of the flat surface of the concave portion of the insulating layer gradually decreases to a predetermined size, and then the insulating layer on the flat surface is opened to form a seed portion (6). step, growing a non-single crystal layer (3) on the insulating layer, covering the seed portion.

irradiating the non-single-crystal layer on the seed portion with an energy beam and recrystallizing the non-single-crystal layer by scanning in the lateral direction.

[Industrial application field]

The present invention relates to a method for manufacturing a semiconductor device, and particularly to a method for manufacturing a Sol structure.

In recent years, the Sol structure has been used in CMOS ICs, three-dimensional ICs, etc. due to the miniaturization of elements accompanying the increase in the degree of integration of semiconductor devices.

[Prior Art] One of the conventional Sol structure formation techniques is to heat a non-single crystal layer, which is partially in contact with a single crystal substrate and the rest is formed on an insulating layer, by laser irradiation or radiation irradiation.

There is a lateral solid phase growth method in which recrystallization is performed in the lateral direction from a seed portion in contact with a single crystal substrate.

In this method, it is necessary to control the surface temperature distribution during recrystallization in order to obtain a single crystal layer over a wide area on the insulating layer.

FIG. 2 is a cross-sectional view illustrating a conventional lateral solid phase growth method.

In the figure, an insulating layer 2 with a seed portion opened is formed on a single crystal substrate l, and a polycrystalline or amorphous non-single crystal layer 3 is grown over the entire surface of the substrate.

Next, the non-single crystal layer 3 is irradiated with an energy beam such as a laser beam from the seed part to recrystallize this layer, and the beam is scanned over the non-single crystal layer 3 formed on the insulating layer 2.
This layer is successively recrystallized.

At this time, the opening of the insulating layer 2 in the seed portion is formed by patterning using lithography, and one level difference is steep.

[Problems to be Solved by the Invention] However, during the process of crystal growth from the seed portion onto the insulating layer, the film thickness of the insulating layer changes rapidly and the surface temperature cannot be adequately controlled, resulting in a wide single crystal region. I couldn't get it.

The purpose of the present invention is to obtain a single crystal layer with good crystallinity over a wide range by smoothly controlling the surface temperature during recrystallization when forming a Sol structure by lateral solid phase epitaxy. shall be.

[Means for solving the problem] The solution to the above problem is to form an insulating layer (2) on a single crystal substrate (1).
, and an oxidation-resistant first mask pattern (
4), selectively thermally oxidizing the substrate to remove the first mask pattern; forming an oxidation-resistant second mask pattern (5) on the flat surface of the recess of the insulating layer; selectively thermally oxidizing and removing the second mask pattern;
The above steps are repeated until the area of the flat surface of the concave portion of the insulating layer gradually decreases to a predetermined size, and then the insulating layer on the flat surface is opened to form a seed portion (6). step, and a non-single crystal layer (3
), irradiating the non-single-crystal layer on the seed portion with an energy beam, and recrystallizing the non-single-crystal layer by scanning in the lateral direction.

[Effect]

The present invention uses repeated selective oxidation that is performed by gradually reducing the oxidation-resistant mask formed in the same area on the substrate, and gradually increases the thickness of the insulating layer as it moves away from the seed part in contact with the single crystal. This method improves the recrystallization conditions by creating a gradient in the surface temperature at the time of heating and preventing sudden temperature changes from occurring at the boundary between the seed portion and the insulating layer.

〔Example〕

FIGS. 1 (1) to (6) are cross-sectional views illustrating a lateral solid phase growth method according to an embodiment of the present invention.

In FIG. 1 (1), a single crystal substrate 1 is made of single crystal Si.
A substrate is used, and an insulating layer 2 with a thickness of 500 mm is applied on top of the substrate.
Form an i02 layer.

Next, a Si and N4 layer is grown on the entire surface of the insulating layer 2 using a vapor phase epitaxy (CVD) method, and this layer is patterned to leave a seed part included, as an oxidation-resistant first mask pattern 4. 5iJn pattern is formed.

In FIG. 1(2), using the first mask pattern 4 as a mask, the substrate is subjected to wet thermal oxidation to make the thickness of the insulating layer 2 (flat portions on both sides) 3000 mm.

Next, the first mask pattern 4 is removed using hot phosphoric acid.

In FIG. 1 (3), a second
A 5iJn pattern is formed as a mask pattern 5.

At this time, the second mask pattern 5 is the same as the first mask pattern 4.
It is smaller and includes a seed portion.

In FIG. 1 (4), using the second mask pattern 5 as a mask, the substrate is wet thermally oxidized to reduce the thickness (
5,000 people (flat areas on both sides).

Next, the second mask pattern 5 is removed using hot phosphoric acid.

Thereafter, the above steps are repeated until the flat surface of the concave portion of the insulating layer 2 matches the size of the seed portion (in this case, the thickness of the flat portions on both sides is 1 μm).The insulating layer on the seed portion is removed, and the substrate surface is to expose.

By repeating this process, the thickness of the insulation N2 can be given a gentle gradient.

In FIG. 1 (5), a non-single crystal layer 3 with a thickness of 400 mm is formed on the insulating layer 2 covering the seed part 6 using the CVD method.
0 polycrystalline silicon (poly-Si) layer or amorphous silicon (a-
5i) Grow layers.

In FIG. 1 (6), a CW (continuous wave)-Ar laser beam is irradiated to the non-single crystal layer 3 on the seed part 6 and scanned in the lateral direction to form a single crystal layer on the inclined insulating layer 2. Grow 3A laterally.

An example of the recrystallization conditions at this time is first order.

Laser power: 3- Beam diameter = approximately 10 μm (melt width 12-13 μm) Beam scanning speed: 150 mm/see Substrate temperature:
500°C Next, numerical examples showing the effects of the present invention are shown in the table below in comparison with the conventional example.

Crystallinity Single crystallized area (distance x width) Conventional example Polycrystalline nucleus generation 4 μm x 10 μm (grain boundary generation) Example Crystal subgrain boundary generation 10 μm x 12 μm Here,
The single crystallized area is the value of the laser irradiated area per seed part.

The single crystallized area is expressed as the product of the distance in the scanning direction and the width of the molten part, and the embodiment can form a single crystal over a larger area than the conventional example at the time of irradiation before laser scanning, and this area is used as the nucleus. Single crystallization has become possible over a wide range by laser scanning.

[Effects of the Invention] As explained above, according to the present invention, when forming an SOI structure by lateral solid phase epitaxy, the surface temperature during recrystallization can be smoothly controlled, and a wide range of A single crystal layer with good crystallinity can be obtained.

[Brief explanation of drawings]

FIGS. 1 (1) to (6) are cross-sectional views illustrating a lateral solid phase growth method according to an embodiment of the present invention. FIG. 2 is a cross-sectional view illustrating a conventional lateral solid phase growth method. In fig. ■ is a single crystal substrate, which is a single crystal Si substrate. 2 is an insulating layer, which is a SiO□ layer. 3 is a non-single crystal layer, which is a poly-Si layer or an a-Si layer. 3A is a single crystal layer, which is a single crystal Si layer. 4 is the first mask pattern, which is a Si3N4 pattern. 5 is the second mask pattern, which is a 5ilN4 pattern. 6 is the seed part Figure 1 (Part 1) 6. Seed part actual example 0 sectional view Figure 1 (Active Z)

Claims (1)

[Claims] An insulating layer (2) is deposited on a single crystal substrate (1), an oxidation-resistant first mask pattern (4) is formed on the insulating layer, and the substrate is selectively thermally oxidized. , removing the first mask pattern, forming an oxidation-resistant second mask pattern (5) on the flat surface of the recess of the insulating layer, selectively thermally oxidizing the substrate, and removing the second mask pattern. The removing step and the above steps are repeated until the area of the flat surface of the recess of the insulating layer gradually decreases to a predetermined size, and then the insulating layer on the flat surface is opened to form a seed portion ( 6), and growing a non-single crystal layer (3) on the insulating layer covering the seed part, irradiating the non-single crystal layer on the seed part with an energy beam and scanning it in the lateral direction. A method for manufacturing a semiconductor device, comprising the step of recrystallizing the non-single crystal layer.