JPH04271115A - Manufacture of semiconductor - Google Patents

Abstract

PURPOSE:To obtain a semiconductor manufacturing method capable of forming a silicon film excellent in flatness and crystallinity wherein orientation in the XY surface is uniform, regarding a method for forming a silicon film excellent in crystallinity wherein orientation is uniform, on an insulating film. CONSTITUTION:In a semiconductor manufacturing method for forming a silicon film 5 on an insulating film 2, trenches 4 are formed in the insulating film 2, a silicon film 5 is deposited at a temperature of 400-600 deg.C on the insulating film 2 in which the trenches 4 are formed, and annealing is performed at a temperature of 400-700 deg.C, after the surface is irradiated in a spot manner with an energy beam like an argon laser beam.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a silicon film with uniform orientation and good crystallinity on an insulating film.

In order to improve the degree of integration of semiconductor devices,
It is necessary to miniaturize the dimensions of each element. To this end, in addition to reducing the two-dimensional dimensions, it is essential to make the film thinner in forming the multilayer structure. In this case, it is necessary that the thin film has a uniform thickness and a flat surface in order to prevent disconnection of the film formed in the upper layer.

[0003] Furthermore, in order to prevent impurity elements in the film from diffusing during heat treatment in a subsequent process, it is also necessary to lower the temperature of the manufacturing process.

[0004] In summary, there is a need in the miniaturization process for a manufacturing technique that deposits a film with a uniform thickness at a low temperature and also improves the orientation and crystallinity of the deposited thin film.

[0005]

2. Description of the Related Art When a silicon film is formed on a silicon oxide film, the deposition temperature is usually 620 to 630° C., and the silicon film in this case becomes polycrystalline. In order to further flatten and thin the silicon film, methods of depositing it at lower temperatures are being considered.

For example, when deposited at a temperature of 600° C. or lower, an amorphous silicon film is formed. Since this silicon film is not crystallized, even if the film thickness is reduced, the film thickness will be uniform and the surface will be extremely flat. When this film is annealed, crystallization progresses from the base oxide film interface,
After the crystallization is complete, the grain size reaches a maximum of 1 μm or more. Therefore, grain boundaries are reduced, and as a result, a silicon film with high mobility in electrical characteristics is obtained.

[0007]

[Problem to be solved by the invention] When amorphous silicon formed on an oxide film crystallizes, the crystallization starting position is said to be from the base oxide film, but it is not possible to accurately control the position. Not done. Therefore, grain boundaries are formed in the element formation region, and crystal grains are oriented in a specific plane direction in the Z-axis direction.
As shown in the figure, the orientation is uneven, and as a result, good mobility cannot be obtained at present.

The purpose of the present invention is to eliminate this drawback, and in addition to having good flatness and crystallinity,
An object of the present invention is to provide a semiconductor manufacturing method capable of forming a silicon film with uniform orientation in its plane.

[0009]

[Means for solving the problem] The above purpose is to achieve an insulating film (
2) In a semiconductor manufacturing method in which a silicon film (5) is formed on the insulating film (2), grooves (4) parallel to each other are formed in a predetermined direction of the insulating film (2), and the A silicon film (5) is deposited on the insulating film (2) of
This is achieved by a semiconductor manufacturing method that performs annealing after spot-wise irradiation with an energy beam. The energy beam is preferably an argon laser beam and has a light intensity that does not melt the silicon film (5), and the silicon film (5) is deposited at a temperature of 400 to 600°C. The annealing temperature is preferably 400 to 700°C. Furthermore, it is effective to irradiate the energy beam at the center of the region of the silicon film (5) where the elements are to be formed.

0010

[Operation] Using a method called graphoepitaxy method, as shown in FIGS. 2(b) and 2(c), grooves 4 are formed in a specific direction in the silicon oxide film 2, and a silicon film is formed on the grooves 4. 5 is deposited and annealed, the silicon film 5 grows crystals in an energetically stable direction, as shown in the figure.
Good orientation can be obtained. However, with this method, it is not possible to control the position of the nucleus where the crystal starts.

On the other hand, it has been confirmed that when a silicon film is deposited at a low temperature on a flat silicon oxide film and annealed after spot irradiation with a laser, the spot irradiated with the laser becomes a nucleus and crystal growth occurs. . Furthermore, evaluation by Raman spectroscopy has confirmed that each crystal has good crystallinity. However, in this method, the crystal orientation in the XY plane becomes irregular.

Therefore, the semiconductor manufacturing method according to the present invention makes it possible to control the crystal orientation and the position of nucleus generation by combining the above two methods.

That is, grooves 4 are formed in silicon oxide film 2 using lithography. Usually, a silicon wafer with a (100) plane is used, so the shape of the groove is shown in Figure 2.
It may be rectangular as shown in (b). On top of this is a silicon film 5.
is deposited at a temperature of 400 to 600°C, spot irradiated with an energy beam such as a laser, electron beam, or ion beam, and then annealed at a temperature of 400 to 700°C.
The spot irradiated with the energy beam becomes a nucleus and the crystal grows in a specific direction, and the crystal grains are large and
A silicon film with good orientation is formed.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A semiconductor manufacturing method according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a process diagram for forming a silicon film. As shown in the figure (a), a thermal oxide film 2 with a thickness of 1 μm is formed on the (100) plane of a silicon substrate 1, a resist film 3 is applied thereon, and this is coated using a photolithography method. It is patterned and remains in the form of a blind at intervals of 4 μm. Next, as shown in FIG.
Using as a mask, oxide film 2 is etched to a depth of 300n.
m grooves 4 are formed. It goes without saying that the groove spacing and depth are not limited to these values.

Using the CVD method, disilane (Si2 H6) is reacted at a temperature of 450.degree. C. to deposit an amorphous silicon film 5 with a thickness of 400 nm, as shown in FIG. 2(c).

As shown in FIG. 2D, an argon laser is focused and irradiated onto the silicon film 5. In the same figure,
6 is a laser source, 7 is a microscope, 8 is a mirror, 9 is an objective lens, and 10 is an XY stage. Although the laser intensity generated by the laser source 6 varies depending on the optical system, it must be selected to an intensity that does not melt the silicon film. In this example, it was set to 40 mW. A 100x magnification lens is used as the objective lens 9 of this intensity microscope to focus the laser beam diameter to about 1 μm, and the silicon film 5 is irradiated for about 1 second. The silicon substrate 1 is moved using the XY stage 10, and a plurality of seeds are formed in the silicon film 5 by sequentially irradiating the silicon substrate 1 with a laser beam at intervals determined depending on the size of the device. Then, at a temperature of 650°C, 3
Anneal for 0 minutes. Note that the annealing temperature varies depending on the sample structure and film quality.

Note that if the irradiation position of the laser beam is selected at the center of the element formation region, crystal grain boundaries will not be formed in the element formation region, improving the mobility in electrical characteristics and producing elements with good performance. can be formed.

[0019]

[Effects of the Invention] As explained above, in the semiconductor manufacturing method according to the present invention, grooves parallel to each other are formed in a predetermined direction in an oxide film, and a flat amorphous silicon film is deposited on the grooves at a low temperature. Since this is annealed by spot-wise irradiation with an energy beam, it is possible to control both the position and orientation of the nucleus where the crystal begins, creating a silicon thin film with a flat surface and good crystal orientation. can be formed. This method leads not only to improved crystallinity but also to increased mobility in electrical characteristics, and greatly contributes to improving the performance of semiconductor devices.

[Brief explanation of the drawing]

FIG. 1 is a process diagram for manufacturing a silicon film according to the present invention.

FIG. 2 is a diagram showing the relationship between the surface shape of an oxide film and the plane orientation of a silicon film formed thereon.

[Explanation of symbols]

1 Silicon substrate 2 Insulating film (silicon oxide film) 3 Resist film 4 Groove 5 Silicon film 6 Laser source 7 Microscope 8 Mirror 9 Objective lens 10 XY stage

Claims (3)

[Claims] 1. A semiconductor manufacturing method in which a silicon film (5) is formed on an insulating film (2), in which grooves (4) parallel to each other are formed in a predetermined direction of the insulating film (2); 4
) on the insulating film (2) formed with a silicon film (5).
A semiconductor manufacturing method characterized by depositing a substance, irradiating it spot-wise with an energy beam, and then annealing it. 2. The semiconductor manufacturing method according to claim 1, wherein the energy beam is an argon laser beam and has a light intensity that does not melt the silicon film (5). 3. The semiconductor manufacturing method according to claim 1, wherein the energy beam is irradiated at the center of a region of the silicon film (5) where an element is to be formed.