JPS63265419A - Manufacture of semiconductor crystal layer - Google Patents

Abstract

PURPOSE:To form a single crystal semiconductor film for shaping an upper layer element without giving thermal damage to a lower layer element while simplifying a manufacturing process for the semiconductor film, increasing the area of an element forming region and flattening a stepped section on an opening section in an insulating film on a substrate by forming the semiconductor film in the opening section to a recessed shape. CONSTITUTION:An silicon oxide film 12 is deposited onto a semiconductor substrate 11, and an opening section 13 is shaped to one part of the silicon oxide film 12. A polycrystalline silicon film 14 is deposited onto the whole surface. The whole surface of the polycrystalline silicon film 14 is etched until the surface of the silicon oxide film 12 is exposed. A polycrystalline silicon film 15 is deposited onto the whole surface again, and the surface of the polycrystalline silicon film 15 is formed to a recessed shape that the surface shape of the polycrystalline silicon film 14 as a first layer is reflected in the opening section 13. An silicon oxide film 16 is deposited onto the whole surface as a protective film, the substrate 11 is heated while quasi linear electron beams 17 are applied, and the polycrystalline silicon film 16 is melted and recrystallized. Accordingly, the polycrystalline silicon film 15 is changed into an excellent single crystal film by growth from the opening section 13.

Description

[Detailed description of the invention] [Object of the invention] (Prior art) In recent years, so-called SOI (SOI
111con on In5ulator) technology is being actively developed. Furthermore, development of three-dimensional ICs in which elements are formed three-dimensionally using this technology is also underway. This 3D IC is produced by forming a 3-dimensional CT layer on the backside of a semiconductor wafer;
It is manufactured by forming a single crystal semiconductor film (by SOI technology) and then forming an element (upper layer element) on the single crystal semiconductor film.

By the way, in order to form a single crystal semiconductor film for forming an upper layer element, a technique for controlling the crystal orientation is required. As this technique, the lateral seeding epitaxial growth method is widely used because it can reliably control the crystal orientation and can increase the area of single crystallization. In this growth method, when forming a single crystal semiconductor film for forming an upper layer element using an energy beam, the lower semiconductor single crystal is grown from the opening of the interlayer insulating film using a lateral seeding epitaxial method. When creating a semiconductor film, in the conventional sample structure, when the semiconductor film is melted by an energy beam,
It is difficult to melt the semiconductor film in the opening of the interlayer insulation group without causing thermal damage to the underlying elements. In order to solve this problem, methods of reducing the opening area by dividing the opening into stripes, making the opening into dots, etc. have been studied.

This makes it possible to limit the area of the opening to the minimum size necessary for forming a single crystal semiconductor film and facilitate melting of the semiconductor film in the opening. However, in order to further reduce the flow of heat to the lower layer elements and to sufficiently reduce thermal damage to the lower layer elements, it is necessary to thicken the interlayer insulating layer to 1 μm or more. Melting of the membrane was difficult.

As a countermeasure for this problem, there are methods such as creating a slope in the interlayer insulating film at the opening and making the polycrystalline or amorphous semiconductor film thicker in the opening and its surrounding area than in other parts. It has been proposed and has shown some effectiveness. however,
In this type of method, the number of steps is increased and the area occupied by the opening is increased, resulting in an element-regulating interlayer insulating film, 13 is the opening, 15 is a polycrystalline or amorphous silicon film, and 16 is a protective film.

(Problems to be Solved by the Invention) Conventionally, when creating a single crystal semiconductor film for forming an upper layer element using an energy beam without causing thermal damage to the C lower layer element, the number of steps increases, There have been problems such as a reduction in the element forming area and flattening of the opening when forming a multilayer structure.

The present invention has been made in consideration of the above circumstances.

The purpose is to be able to create a single crystal semiconductor film for forming upper layer elements without causing thermal damage to lower layer elements, and to simplify the manufacturing process.

It is an object of the present invention to provide a method for manufacturing a semiconductor crystal layer, which can increase the area of an element formation region and facilitate flattening of steps on an opening, and is suitable for manufacturing a three-dimensional IC.

[Structure of the Invention (Means for Solving Problems)] The gist of the present invention is to provide energy beam irradiation by forming the semiconductor film in the opening into a concave shape.1: Uniformity of the semiconductor film during irradiation The i
?・j1 That is, the present invention has a partial opening on the semiconductor substrate.
After forming an insulating film, a polycrystalline or amorphous semiconductor film is deposited on the insulating film and on the dead conductor substrate exposed in the opening, and this semiconductor film is formed into a concave shape in the opening. In this method, the semiconductor film is formed into a single crystal by scanning the semiconductor film while irradiating it with an energy beam.

(Function) According to the present invention, the distance between the semiconductor substrate in the opening and the energy beam heating part can be shortened compared to the conventional method, and the distance between the semiconductor substrate in the opening and the energy beam heating part can be shortened, and the interlayer insulating film Even if the thickness is increased, the semiconductor film in the opening is easily dissolved. Therefore, the amount of energy beam irradiation can be reduced compared to the conventional method, and thermal damage to lower layer elements can be reduced. In addition, the interlayer insulation M of the opening
XK does not require an inclined portion, and therefore the manufacturing process is simplified. Furthermore, since the unevenness of the single-crystal semiconductor film is only a small depression above the opening, it can be used for a long time, eliminating the need for a cap.

(Example) Hereinafter, the details of the present invention will be explained by referring to an example shown in one figure.

Figure 1 shows a single crystal IJ according to an embodiment of the method of the present invention.
:ry. ,Building process, 8 ocution, figure, ah. First, as shown in FIG.
A silicon oxide film (interlayer insulating film) 12 with a thickness of μm is deposited, and a portion of this silicon oxide film 12 is coated by RIE. )2At
An opening 13 of Iφ is formed. Subsequently, a polycrystalline silicon film (semiconductor film) 14 was deposited on the entire surface to a thickness of 2 μm.

Note that it is assumed that a predetermined element (lower layer element) is formed on the silicon substrate 11. Furthermore, although the openings 13 are arranged in dots as shown in FIG. 2(a), they may be formed in stripes as shown in FIG.

Then, using a chemical dry etching (CDI) method,
The entire surface of the polycrystalline silicon film 14 was etched until the surface of the silicon oxide film 12 was exposed. At this time, the opening 13
The inner polycrystalline silicon film 14 had a concave shape as shown in FIG. 1(b). Incidentally, in the above-mentioned CDEO, a mixed gas of CF4 and 02 was used as an etching gas.

Next, as shown in FIG. 1(,), polycrystalline silicon WX15 was deposited again on the entire surface to a thickness of 0.81Ar, resulting in a concave shape reflecting the shape of the original.

1. Next, as shown in FIG. 1(d), after depositing a silicon oxide film 16 to a thickness of 0.5 m on the entire surface as a protective film, the substrate 11 is heated to 600° C. and a pseudo linear electron beam 11 is deposited on the entire surface. was irradiated to melt and recrystallize the polycrystalline silicon film 16. Here, the pseudo-linear electron beam is a beam that is virtually made into a linear electron beam by deflecting the beam at high speed in a direction perpendicular to the beam scanning direction. In addition, the conditions for beam irradiation include an accelerating voltage of 10 kV,
Beam length 0.8 μ width, beam deflection frequency 30 MHz
, beam modulation frequency 10 kHz, beam scanning speed 1
00+g@/s@e.

As a result, the polycrystalline silicon film 15 grew from the opening 13 and became a good single crystal film. Nine.

The lower layer element formed on the silicon substrate 1 did not suffer any inconvenience such as deterioration of its characteristics (due to thermal damage during beam annealing).

Thus, according to the method of this embodiment, a high-quality single-crystal silicon film can be formed on the insulating film 12, and a remarkable effect can be obtained compared to the conventional method. That is.

In the conventional method, the opening of the interlayer insulating film is sloped. In contrast, with the method of this embodiment, even if the glabella insulating film was 2 cm thick, it was possible to form a polycrystalline silicon film into a single crystal. Furthermore, the peeling of the silicon film near the opening, which has been observed in the past, did not occur at all.

Further, according to experiments conducted by the present inventors, it has been confirmed that the same effect can be obtained even when the thickness of one interlayer insulating film is 4 μm. Similar effects were obtained even when the diameter of the opening was reduced to 0.8 μmφ. Furthermore, similar effects were obtained when the openings were formed into stripes.

Note that the present invention is not limited to the method of the embodiment described above. For example, as the energy beam, a spot or linear electron beam may be used instead of the quasi-linear electron beam, and a Lede beam or a strip heater may also be used. Also,
Semiconductor films that become monocrystalline are not limited to polycrystalline silicon.

It may also be amorphous silicon. Furthermore, in place of silicon, Go, GaAa, GaP, In
It is also possible to use P, etc.

Further, the concave shape of the semiconductor film in the opening part 1 can be used. Keep it as well! ! As for the film, in addition to the above-mentioned insulating films, metal films such as W, TI, and AA can be used.
It is also possible to use membranes. In addition, various modifications can be made without departing from the gist of the present invention.

[Effects of the Invention] As detailed above, according to the present invention, a single crystal semiconductor film can be formed on an insulating film without causing thermal damage to underlying elements, and the element formation area can be increased and The planarization process can be facilitated. Therefore, great effects can be obtained when applied to the manufacture of three-dimensional ICs, etc.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the manufacturing process of a single-crystal silicon film according to a method according to an embodiment of the present invention, FIG. 2 is a schematic diagram showing the shape of an opening, and FIG. 3 is a cross-sectional view for explaining a conventional method. It is a diagram. 11-... Single crystal silicon substrate (semiconductor substrate), 12.
・・Silicon oxide II & (interlayer insulation j!K), 13−・
- Opening, 14.15... Polycrystalline silicon film (semiconductor M). 11ζ16...Protection Ms J y...Electron beam (
energy beam). -・１ ２′ Applicant Kozo Iizuka, Director General of the Agency of Industrial Science and Technology Figure 1

Claims (4)

[Claims] (1) A step of forming an insulating film having a partial opening on a semiconductor substrate, depositing a polycrystalline or amorphous semiconductor film on the insulating film and the semiconductor substrate exposed in the opening, and A method for manufacturing a semiconductor crystal layer, comprising the steps of: forming a semiconductor film in a concave shape in the opening; and converting the semiconductor film into a single crystal by scanning while irradiating an energy beam. (2) As the step of forming the polycrystalline or amorphous semiconductor film, first, after depositing a first layer of semiconductor film,
Claim 1, characterized in that the entire surface of the semiconductor film is etched by a chemical dry etching method to leave the semiconductor film in a concave shape within the opening, and then a second layer of semiconductor film is deposited again. A method for manufacturing a semiconductor crystal layer. (3) The method for manufacturing a semiconductor crystal layer according to claim 1, wherein the openings are formed in a dotted line. (4) The method for manufacturing a semiconductor crystal layer according to claim 1, wherein an insulating film or a metal film is formed on the semiconductor film before the single crystallization step of the semiconductor film.