JPS6211218A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To obtain recrystallized silicon having a large area and excellent crystallizability onto an insulating substrate by a method wherein a recessed section is formed to the surface of an insulating film shaped onto a single crystal semiconductor substrate, an opening section reaching the surface of the substrate from the bottom of the recessed section is formed, a semiconductor layer is shaped to the opening section and the surface of the insulating film and the semiconductor layer is recrystallized through heating. CONSTITUTION:An Si oxide film 12 is shaped onto a single crystal Si substrate 11, a resist pattern 15 with openings in regions as seed sections is formed onto the oxide film 12, and the silicon oxide film 12 is wet-etched. The film 12 is dry-etched in an anisotropic manner up to the surface of the substrate 11 to shape the species regions. The resist 15 is removed, and polysilicon is deposited and recrystallized through heating. Accordingly, since the areas of contact sections among polysilicon as species and the single crystal substrate 11 are reduced, heat flux in the direction of the substrate 11 can be minimized, and the temperature difference of the species sections and an SOI section can be lowered, thus generating no peeling, etc., then acquiring recrystallized Si having a large area and excellent crystallizability.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to a 'II manufacturing method of a semiconductor device for obtaining a large area and highly crystalline single crystal silicon on an insulating substrate.

Conventional technology In recent years, a technology for recrystallizing polysilicon deposited on an insulating substrate (hereinafter referred to as RSO [formation technology]) has been developed.
It has become extremely important in terms of increasing the speed and making three-dimensional integrated circuits possible.

By the way, conventional Sol formation technology melts polysilicon by irradiating the polysilicon deposited on an insulating substrate with an energy beam such as a laser or an electron beam, or heating it with a strip heater, etc. The aim was to achieve single crystallization through solidification. However, in order to form an integrated circuit on recrystallized silicon, the recrystallized silicon needs to have a large area and good crystallinity. Conventionally, for example, as shown in FIG. 5, a part of an insulating plug 2 on a single crystal silicon substrate 1 is opened to secure a seed area for crystal growth, and then a polysilicon layer 3 is deposited on the entire surface. However, a method in which laser irradiation is performed from above to grow crystals using the seed region as a nucleus (hereinafter referred to as "lateral seeding epitaxy") has been widely adopted. Note that 4 is a cap layer.

Problems to be Solved by the Invention However, in the conventional method described above, since there is a large difference in thermal conductivity between silicon and the insulating substrate 2, the polysilicon layer on the seed portion and the insulating substrate 2 is heated. 3〈hereinafter r
A temperature difference occurs between the 801 layer 3 and the 801 layer 3, which makes it difficult to obtain recrystallized silicon with good crystallinity over a large area.

The present invention solves the above-mentioned conventional problems, and aims to provide a method for manufacturing a semiconductor device that can obtain recrystallized silicon with good crystallinity over a large area on an insulating substrate.

Means for Solving the Problems In order to solve the above problems, the method for manufacturing a semiconductor device of the present invention includes a step of forming an insulating film on a single crystal semiconductor substrate, and forming a recess on the surface of the insulating film. forming an opening in the insulating film with a depth reaching from the bottom of the recess to the surface of the single crystal semiconductor substrate; The method includes a step of forming a semiconductor layer, and a step of heating and recrystallizing the semiconductor layer.

Effect According to the above method, the area of the seed region is reduced, the heat flux in the direction of the single crystal silicon substrate is reduced, and on the contrary, the heat flux to the edge portion of the insulating substrate is increased, and the seed region and the
The temperature difference between the 01 layer and the 01 layer will be reduced. As a result, problems such as removal of the 801 layer do not occur, and recrystallized silicon with good crystallinity can be formed over a large area.

EXAMPLE Hereinafter, an example of the present invention will be described based on FIGS. 1 to 4.

FIG. 1 is a cross-sectional view of a semiconductor device obtained by a method for manufacturing a semiconductor device according to an embodiment of the present invention, in which 11 is a single crystal silicon substrate, and 12 is a single crystal silicon substrate formed by thermal oxidation to a thickness of about 1 μm. Alternatively, 13 is a silicon oxide film deposited by a CVD method, a polysilicon layer having a thickness of about 0.5 μm, and 14 is a cap layer.

In manufacturing the above semiconductor device, first, as shown in FIG. 2, a silicon oxide film 12 of about 1 μm is formed on a single crystal silicon substrate 11, and an opening is formed on the silicon oxide film 12 in a region that will become a seed portion. After forming the resist pattern 15, the third
As shown in the figure, the silicon oxide film 12 is wet-etched for 6 minutes using an etching solution such as buffered hydrofluoric acid through the opening. Next, as shown in Figure 4,
The silicon oxide film 12 is etched to the surface of the single crystal silicon substrate 11 by anisotropic dry etching to form a seed region. After this, after removing the resist 15,
The steps of depositing polysilicon and recrystallizing it by lateral seeding epitaxy are conventional.

When the seed region is configured as described above, the area where the polysilicon serving as the seed and the single-crystal silicon substrate 11 are in contact is small, so that the heat flux in the direction of the single-crystal silicon substrate 11 can be reduced. . On the other hand, since the oxide film edge portion is formed by wet etching, it has a spherical shape and has a large area. Therefore, the heat flux to the edge portion can be increased. In other words, since the temperature difference between the seed portion and the 801 layer can be reduced, problems such as peeling of the 801 layer do not occur, and recrystallized silicon with a large area and good crystallinity can be obtained.

Effects of the Invention As described above, according to the present invention, recrystallized silicon with high crystallinity in cross-sectional area can be formed by an extremely simple method, and its industrial utility value is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a semiconductor device obtained by a method for manufacturing a semiconductor device according to an embodiment of the present invention, FIGS. 2 to 4 are cross-sectional views at each step of the method for manufacturing the semiconductor device, and FIG. is a cross-sectional view of Sol formed by conventional lateral seeding epitaxy. 11... Single crystal silicon substrate, 12... Silicon oxide film, 13... Polysilicon layer, 14... Cap layer agent Yoshihiro Morimoto Figure 1 Figure 4 Figure Z

Claims (1)

[Claims] 1. Forming an insulating film on a single crystal semiconductor substrate, forming a recess on the surface of the insulating film, and forming an opening with a depth reaching from the bottom of the recess to the surface of the single crystal semiconductor substrate. A step of forming a polycrystalline or amorphous semiconductor layer on the insulating film, a step of forming a polycrystalline or amorphous semiconductor layer on the opening and a surface of the insulating film, and a step of heating the semiconductor layer to recrystallize it. A method for manufacturing a semiconductor device.