JP2003100628A - Forming method of semiconductor film and semiconductor device as well as display device manufactured by employing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce occurrence of an irregular crystalline grain boundary and to control a position whereat the crystalline grain boundary occurs. SOLUTION: An amorphous or polycrystalline state Si film 1 formed on a substrate is formed so as to have a pattern having a main area 1b with a given widthwise size and a terminal area 1a, whose widthwise size is sequentially reduced from one end of the main area 1b and becomes zero at the tip end of the same, while a laser beam formed so as to be a beam spot 2 having a recessed non-heating area 2a at the rear side with respect to a scanning direction is positioned, so that the fore part of the recessed non-heating area 2a formed on the beam spot 2 is projected to the tip end of the end area 1a of the Si film 1, then, the laser beam is scanned from the end area 1a of the Si film 1 toward the main area 1b of the same.

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 semiconductor film and a semiconductor device and a display device manufactured by the method, and more particularly, to a semiconductor device formed on a non-single crystal insulating film or a non-single crystal insulating substrate. A method for forming a semiconductor film, in which an energy beam is applied to an amorphous or polycrystal semiconductor film formed by heating to crystallize the amorphous semiconductor film, and a high-performance semiconductor film using the semiconductor film is formed. The present invention relates to a semiconductor device such as a liquid crystal driver, a semiconductor memory and a semiconductor logic circuit, and a display device using these semiconductor devices.

[0002]

2. Description of the Related Art Conventionally, a semiconductor film such as an amorphous or polycrystalline film is formed on a non-single crystal insulating film formed on a substrate or on a non-single crystal insulating substrate, and the semiconductor film is irradiated with an energy beam. A method of crystallizing a semiconductor film is known. When a crystalline semiconductor film is formed by this method,
In order to prevent the existence of crystal grain boundaries in the device formation region, it is possible to suppress the generation of many irregular crystal nuclei in a semiconductor film such as an amorphous material by irradiation with an energy beam, and also to form crystal grain boundaries. It is important to control the position to move.

In Japanese Patent Laid-Open No. 58-85519 (hereinafter, referred to as Conventional Example 1), a Si film 28 is patterned in a predetermined shape on a rectangular insulating substrate 27 as shown in FIG. There is disclosed a method of applying heat energy by heating. In Conventional Example 1, the Si film 28 is provided over the entire surface of the insulating substrate 27 except one side edge portion. The Si film 28 has a main region 28b provided in a region other than the side edge of the insulating substrate 27 and a small region 28a provided in the center of the side edge of the insulating substrate 27. In the region 28b, the width dimension of the side edge portion continuous with the small region 28a is gradually reduced as the width dimension approaches the small region 28a. In the method of Conventional Example 1, the narrow region 2 of the Si film 28 is
The crystal nucleus formed in 8a serves as a seed crystal, the crystal region spreads from this seed crystal to the main region 28b, and the entire Si film 28 is monocrystallized. In this case, as the Si seed crystal formed in the narrow region 28a, a single crystal piece of Si may be arranged on the narrow region 28a instead of using crystal nuclei that naturally occur in the narrow region 28a.

In addition, Appl. Phys. Lett. V
ol. 70 No. 25 pp. 3434-3436
In (hereinafter, referred to as Conventional Example 2), the Si film 30 patterned on the substrate in a shape as shown in FIG. 11 is irradiated with a laser beam while scanning in the direction of arrow 31, thereby A method of obtaining a single crystal region extending along the scanning direction is disclosed.

[0005]

In the method of forming a semiconductor film of the above-mentioned conventional example 1, the small region 28a to the main region 28b are formed.
In addition to the crystal region crystallized by the seed crystal generated or arranged in the small region 28a, a crystal region in which crystallization is advanced from the crystal nucleus spontaneously generated in any part of the main region 28b is generated as However, irregular grain boundaries may occur.

Further, in the method of forming a semiconductor film of the second conventional example, an elongated single crystal region along the scanning direction of the laser beam is formed in the center of the patterned Si film 30, but the center of the Si film 30 is formed. A polycrystalline region is included in the peripheral portion of the portion to form an irregular grain boundary.

When a semiconductor device (transistor) such as a liquid crystal driver, a semiconductor memory or a semiconductor logic circuit is manufactured using such a semiconductor film having irregular crystal grain boundaries, the carrier mobility becomes small, and the threshold voltage There is a problem that the carrier mobility and the threshold voltage of the semiconductor devices (transistors) formed in a large number in the liquid crystal driver and the like have large variations.

The present invention has been made in order to solve the above problems. Even if the dimensional width is wide, the positions where the crystal grain boundaries are generated are controlled, and irregular crystal grain boundaries are generated. It is an object of the present invention to provide a method for forming a semiconductor film with reduced power consumption, a semiconductor device manufactured by using the method, and a display device.

[0009]

In order to solve the above-mentioned problems, a method of forming a semiconductor film according to the present invention comprises melting an amorphous or polycrystalline semiconductor film formed on a substrate into the semiconductor film. A method for forming a semiconductor film, which comprises crystallizing the semiconductor film by irradiating an energy beam which gives thermal energy while scanning in a constant direction, wherein the semiconductor film comprises a main region having a constant width direction dimension, A pattern is formed on the substrate so that one end of the main region has an end region continuously provided so that the dimension in the width direction becomes gradually smaller as the distance from the main region increases,
The energy beam is given by a beam spot having a concave non-heated region at a rear portion with respect to the scanning direction, and a front portion of the concave non-heated region in the beam spot is irradiated to the outermost portion of the end region of the semiconductor film. The alignment is performed as described above, and the beam spot is scanned from the end region of the semiconductor film toward the main region.

In the method for forming a semiconductor film of the present invention, the patterned semiconductor film has a plurality of main regions and a plurality of end regions continuous with the respective main regions, and the beam spot includes It is preferable that a plurality of concave non-heated regions corresponding to the respective end regions are formed.

In the method for forming a semiconductor film of the present invention, before forming the semiconductor film on a substrate by patterning, a base film having a step portion in which a portion corresponding to a central portion in the width direction of the main region is lowered. Is preferably provided, and the central portion in the width direction of the main region is formed lower than both side edge portions.

In the method of forming a semiconductor film of the present invention, it is preferable that the end region is formed continuously with a central portion of a main region provided on the step.

In the method for forming a semiconductor film of the present invention, it is preferable that antireflection films are provided on both sides of the main region of the semiconductor film before being irradiated with the energy beam, except for the central portion in the width direction. .

In the method for forming a semiconductor film of the present invention, the semiconductor film is preferably a silicon film.

In the method for forming a semiconductor film of the present invention, the energy beam is preferably a laser beam.

In the method for forming a semiconductor film of the present invention, it is preferable that the energy beam is shaped light or point light shaped so that the concave non-heated region is provided.

In the method for forming a semiconductor film of the present invention, it is preferable that the laser beam is intermittently irradiated at intervals of 0.1 μm to 10 μm.

The semiconductor device of the present invention has a semiconductor film formed by the method for forming a semiconductor film of the present invention.

A display device of the present invention includes the above semiconductor device of the present invention.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below in detail with reference to the drawings.

(Embodiment 1) In the method for forming a semiconductor film according to Embodiment 1, a semiconductor such as an amorphous or polycrystalline semiconductor is formed on a non-single crystal insulating film formed on a substrate or on a non-single crystal insulating substrate. A film is provided, patterned into a predetermined shape, and irradiated with an energy beam to single crystallize the semiconductor film.

FIG. 1 is a schematic plan view showing a semiconductor film patterned on a substrate and an energy beam in such a method for forming a semiconductor film.

As shown in FIG. 1, a silicon (Si) film 1 which is a semiconductor film provided on a substrate has a main region 1b formed in a rectangular shape having a constant width direction dimension, and this main region 1
The dimension in the width direction is continuously provided at one end of b, and the dimension in the width direction gradually decreases as the distance from the main region 1b increases, and the dimension in the width direction becomes 0 at the end farthest from the main region 1b.
Is formed into a shape having an end region 1a which is

Then, the S thus patterned is formed.
Beam spot 2 of energy beam for i film 1
As indicated by the arrow 3, from the end region 1a side to the main region 1b
Irradiation is carried out while scanning in a direction orthogonal to the width direction of Si, and the Si film 1 in the amorphous or polycrystalline state is monocrystallized.
The beam spot 2 of the energy beam with which the semiconductor film 1 is irradiated has a shape having a concave non-heated region in the rear portion with respect to the scanning direction. In the first embodiment, as shown in FIG. 1, the beam spot 2 is formed in a substantially V shape so that the central portion side in the direction orthogonal to the scanning direction projects in the scanning direction. Such a beam spot 2 is formed by inclining a pair of linear beam spots in mutually opposite directions and overlapping their front end portions with each other.

Then, this energy beam irradiates the outermost end of the end region 1a of the Si film 1 with the projecting portion located forward of the concave non-heated region 2a formed in the beam spot 2 in the scanning direction. Are aligned as shown in FIG. 1, and the end region 1a of the Si film 1 is aligned as indicated by an arrow 3 in FIG.
The main area 1b is sequentially irradiated with.

FIG. 2A shows a substantially V-shaped beam spot 2 in which a concave non-heated area 2a is formed at the rear portion in the scanning direction, and FIG. 2B shows FIG. 2A. A-A '
2 shows the beam intensity in the cross section along the line, and FIG.
2C shows the temperature distribution of the Si film 1 heated by the irradiation of the beam spot 2 having the beam intensity shown in FIG. 2B.

In the beam spot 2 having a substantially V shape, as shown in FIG.
In the cross section taken along the line AA ′ in (a), as shown in FIG. 2 (b), in each region where the beam spot 2 is irradiated, the beam intensity becomes constant and the beam spot 2 is not irradiated. The beam intensity is 0 in the non-heated area 2a. On the other hand, the temperature distribution of the Si film 1 due to the irradiation of the beam spot 2 is shown in FIG.
2C does not have the same shape as the intensity distribution of the beam spot 2, and as shown in FIG. 2C, the beam spots 2 on both sides of the concave non-heated region 2a become maximum in each irradiated region, Even in the concave non-heated area 2a where the spot 2 is not irradiated, the temperature rises due to heat conduction,
In the concave non-heated area 2a, the temperature is slightly lower than that of each area heated by the irradiation of the beam spot 2.

For this reason, the temperature of the Si film 1 becomes lower in the region outside the region irradiated with the beam spot 2 having a substantially V-shape and in the concave non-heated region 2a of the beam spot 2, so that these Crystal nuclei are generated in the area. Therefore, crystallization progresses from each side of the beam spot 2 toward the concave non-heated region 2a and from the concave non-heated region 2a of the beam spot 2 toward each side.

In the first embodiment, since the concave non-heated region 2a is formed in the rear portion of the beam spot 2 irradiated on the Si film 1 with respect to the scanning direction, the distribution of the heating temperature by the beam spot 2 fluctuates. Even if occurs, the crystallization proceeds in a stable direction, new crystal nuclei are not generated due to fluctuations in the temperature distribution, and the end region 1a having the smallest width dimension of the Si film 1 is formed. It is possible to grow a single crystal stably using the crystal nuclei generated at the end of
A crystalline semiconductor film having a wide crystal region formed of a single crystal can be stably formed.

On the other hand, when the beam spot of the energy beam has a constant beam intensity along the direction orthogonal to the scanning direction, if a slight fluctuation occurs in the temperature distribution of the beam spot, New crystal nuclei are generated at the portion where the fluctuation is generated, and crystallization progresses using the crystal nuclei as seeds, so that an irregular crystal region having a plurality of crystal regions may be formed.

Next, a specific example of the first embodiment will be described.

First, low pressure CVD using Si ₂ H ₆ gas
A Si film 1 which is a semiconductor film is formed to a thickness of 50 nm on an insulating substrate such as a glass substrate by a (chemical vapor deposition) method. The Si film 1 in this state is in an amorphous state. A part of the Si film 1 is etched by a reactive ion etching method (hereinafter referred to as RIE method) using CF ₄ gas and O ₂ gas, and as shown in FIG. A main region 1b having a directional dimension,
A pattern is formed on one end of the main region 1b so as to have a continuous end region 1a such that the widthwise dimension thereof becomes smaller as the distance from the main region 1b increases.

Next, the Si film 1 is irradiated with a laser beam as an energy beam to crystallize the Si film 1 in an amorphous state.

As shown in FIG. 1, this laser beam forms a substantially V-shaped beam spot 2 on the Si film 1, and the front portion of the concave non-heated region 2 a of the beam spot 2 is the Si film 1. Positioning is performed so that the outermost portion of the end region 1a is irradiated, and scanning is performed from the end region 1a of the Si film 1 in a direction orthogonal to the width direction of the main region 1b. In this case, the beam spot 2 is intermittently irradiated at intervals of 0.5 μm. By irradiating this beam spot 2, Si
The portion of the film 1 irradiated with the beam spot 2 is locally heated and melted. Then, the melted portion is further crystallized so that it has crystallinity continuing from the adjacent crystal region, and as a result, a crystal region grown along the scanning direction of the laser beam is formed.

In the first embodiment, first, the Si film 1 is melted from the outermost end of the end region 1a to generate crystal nuclei in this portion, and the crystal nuclei are used as seeds to make the width direction constant. Further, a single crystal crystal region spreads toward the main region 1b of the Si film 1, and as a result, a single crystal semiconductor film in which the crystal region extends in a band shape along the scanning direction of the laser beam can be formed.

(Second Embodiment) FIG. 3 shows the second embodiment.
FIG. 3 is a schematic plan view showing a pattern shape of a Si film 1 formed on a substrate and a beam spot 2 irradiated on the Si film 1 when the semiconductor film forming method of FIG.

In the method of forming a semiconductor film according to the second embodiment, first, Si, which is an amorphous or polycrystalline semiconductor film, is formed on a non-single-crystal insulating film formed on a substrate or on a non-single-crystal insulating substrate. The film 1 is provided and patterned into a predetermined shape.

As shown in FIG. 3, the Si film 1 formed on the substrate has a plurality of main regions 1b formed in a rectangular shape having a constant width direction and one main region 1b at one end thereof. Each of the patterns is formed into a shape having an end region 1a provided continuously. The widthwise dimension of each end region 1a gradually decreases with distance from the main region 1b, and the widthwise dimension becomes 0 at the farthest end farthest from the main region 1b. The main regions 1b adjacent to each other are arranged continuously with each other.

The S thus patterned is formed.
The i film 1 is irradiated with a beam spot 2 while being scanned from each end region 1a side in a direction orthogonal to the width direction of the Si film 1 as shown by an arrow 3 to form an amorphous or polycrystalline state. The Si film 1 that has become a single crystal is crystallized.

The beam spot 2 of the energy beam with which the Si film 1 is irradiated has a shape in which a concave non-heated region 2a is formed in the rear part in the scanning direction corresponding to each main region 1b. The beam spot 2 has a substantially V-shaped scanning direction in which the central portion of the beam spot 2 in the direction orthogonal to the scanning direction of the front portion of each non-heated region 2a provided corresponding to each main region 1b projects in the scanning direction. It is formed in a shape that is continuous in a direction orthogonal to.

In the energy beam, the portions located in front of the scanning direction with respect to the plurality of concave non-heated regions 2a formed in the beam spot 2 are Si.
The edges of each end region 1a of the film 1 are aligned so as to irradiate each of the outermost ends, and as shown by an arrow 3 in FIG.
The i-film 1 is sequentially irradiated to the main region 1b from the outermost end of each end region 1a.

Next, a specific example of the second embodiment will be described.

First, similarly to the method of forming a semiconductor film according to the first embodiment, the Si film 1 which is a semiconductor film is formed to a thickness of 50 nm on an insulating substrate such as a glass substrate. The Si film 1 in this state is in an amorphous state. This Si film 1 is etched by the RIE method,
A pattern is formed in a shape having a plurality of main regions 1b having a constant width direction dimension and a plurality of end region 1a continuously provided at one end of each main region 1b.
The widthwise dimension of each end region 1a gradually decreases with distance from the main region 1b, and the end regions 1a adjacent to each other are continuous with each other.

Next, the Si film 1 is irradiated with a laser beam as an energy beam to crystallize the amorphous Si film 1.

As shown in FIG. 3, this laser beam forms a beam spot in which a plurality of substantially V-shaped shapes are continuous, and each concave non-heated area 2 a of this beam spot 2.
Is aligned such that the frontmost part of each of the end regions 1a of the Si film 1 is irradiated, and a direction orthogonal to the width direction of each main region 1b from each end region 1a of the Si film 1. Scan along. In this case, the beam spot 2 is 0.5μ.
Irradiate intermittently at intervals of m. By the irradiation of the beam spot 2, the portion of the Si film 1 irradiated with the beam spot 2 is locally heated and melted. Then, the melted portion is crystallized so as to maintain the crystallinity continuing from the adjacent crystal region, and as a result, a single crystal crystal region grown along the scanning direction of the laser beam is formed.

In the second embodiment, first, the nuclei of the Si film 1 are melted from the outermost ends of the respective end regions 1a and crystal nuclei are generated in this part, and the crystal nuclei are used as seeds of the Si film 1. A single crystal region spreads toward each main region 1b. In each main region 1b of the Si film 1, the crystal regions grown by using the crystal nuclei generated at each end of each end region 1a as seeds are indicated by points A in FIG. 3 where each main region 1b is continuous. They collide with each other at positions, and a crystal grain boundary (shown by a broken line in FIG. 3) is generated from the point A along the scanning direction of the laser beam.

As a result, in the second embodiment, a semiconductor film having a wide width and a plurality of strip-shaped single crystal regions in which the positions where the crystal grain boundaries are generated are controlled is regularly arranged is formed. be able to.

(Third Embodiment) FIG. 4 shows the third embodiment.
FIG. 3 is a perspective view showing a Si film patterned on a substrate and an energy beam for explaining the method of forming the semiconductor film of FIG.

In the method of forming a semiconductor film according to the third embodiment, before forming the Si film 1 on the substrate 7, a base film 8 which is a lower layer of the Si film 1 is provided. A central portion in the width direction of the base film 8 is a step portion 8a which is thinner than the side portions on both sides. The Si film 1 is formed on the step portion 8a by a later process.
And is patterned so that the length in the longitudinal direction of the Si film 1 provided on the base film 8 is shorter than that of the main region 1b.

Next, the Si film 1 is formed on the base film 8 patterned in the above shape, and then the Si film 1 is formed.
Main region 1b formed in a rectangular shape having a constant width direction dimension
And a shape having an end region 1b continuously provided at one end of the main region 1b. The width of the end region 1a gradually decreases with distance from the main region 1b, and the size of the end region 1a in the width direction becomes 0 at the farthest end from the main region 1b. The main region 1b is formed on the stepped portion 8a of the base film 8, and both side edges are constant so as to overlap the thickened portion of the lower layer base film 8 where the stepped portion 8a is not formed. Patterned with a thickness of. Therefore, the main area 1b
Has a portion stacked on the step portion 8a lower than both side edge portions. Further, the end region 1a of the Si film 1 is provided continuously to the main region 1b located in the step portion 8a formed in the base film 8, and therefore, the maximum dimension in the width direction is the step portion. It matches the dimensional length of 8a in the width direction.

Then, S patterned in this way is formed.
For the i film 1, the same V spot as the beam spot shown in FIG.
The character-shaped beam spot 2 is aligned so that the projecting portion located in the front in the scanning direction with respect to the concave non-heated region 2a is irradiated to the outermost end of the end region 1a of the Si film 1, As shown by arrow 3 in FIG. 4, the end regions 1a to S
Irradiation is performed while scanning in a direction orthogonal to the width direction of the i film 1, and the amorphous or polycrystalline Si film 1 is sequentially single-crystallized from the end region 1a to the main region 1b.

In the third embodiment, the step portion 8a is formed in the underlying film 8 below the Si film 1, and the main region 1b of the Si film 1 is formed.
The inventor of the present application has found that the crystal grain boundaries are generated only in the portion of the underlying film 8 stacked on the stepped portion 8a because both side edges of the base film are higher than the central portion. Therefore, in the method for forming a semiconductor film according to the third embodiment, the position where the crystal grain boundary is wide and wide in the width direction is
Main region 1b laminated on the stepped portion 8a of the underlying layer film 8
A crystalline Si film can be formed so that

Next, a specific example of the third embodiment will be described.

First, a SiO ₂ film as a base film 8 is formed to a thickness of 100 nm on an insulating substrate 7 such as a glass substrate by a plasma CVD method using SiH ₄ gas and O ₂ gas. And RI using CF ₄ gas and CHF ₃ gas
By the E method, the step portion 8a having a depth of 50 nm is formed by etching into a predetermined shape. This step portion 8a is
It is formed along the main region 1b of the Si film 1 provided on the SiO ₂ film which is the base film 8 in a later step, and S
The i-film 1 is formed such that its longitudinal dimension is slightly shorter than that of the main region 1b.

Next, the Si film 1 which is a semiconductor film is formed to a thickness of 50 nm on the substrate 7 and the SiO ₂ film which is the base film 8 by the low pressure CVD method using Si ₂ H ₆ gas.
The Si film 1 in this case is in an amorphous state.
CF ₄ gas and O ₂ are applied to a part of the Si film 1.
Etching is performed by RIE using a gas to form a main region 1b having a constant widthwise dimension and an end region 1a at one end of the main region 1b. The end region 1a is
It is continuously provided in the main region 1b portion on the base film 8, and the widthwise dimension is gradually reduced as the distance from the main region 1b is increased.

Next, the Si film 1 is irradiated with a laser beam as an energy beam to crystallize the Si film 1 in an amorphous state.

This laser beam is approximately V on the Si film 1.
Forming a beam spot 2 in the shape of a letter
The front portion of the concave non-heated region 2a is aligned so as to irradiate the outermost portion of the end region 1a of the Si film 1,
Scanning is performed from the end region 1a of the Si film 1 in a direction orthogonal to the width direction of the main region 1b. In this case, the beam spot 2 is intermittently irradiated at intervals of 0.5 μm. By the irradiation of the beam spot 2, the portion of the Si film 1 irradiated with the beam spot 2 is locally heated and melted. Then, the melted portion is further crystallized so that it has crystallinity continuing from the adjacent crystal region, and as a result, a crystal region grown along the scanning direction of the laser beam is formed.

Moreover, since the main region 1b of the Si film 1 is high in both side edges and low in the center in the width direction, the main region 1b is limited to the part where the height increases from the lowered center. Grain boundaries are formed.

(Fourth Embodiment) FIG. 5 shows the fourth embodiment.
FIG. 3 is a perspective view showing a Si film 1 patterned on a substrate and a beam spot of an energy beam for explaining the method of forming a semiconductor film of FIG.

In the method of forming a semiconductor thin film according to the fourth embodiment, before forming the Si film 1 on the substrate 7, a base film 8 which is a lower layer of the Si film is provided. A central portion in the width direction of the base film 8 is a step portion 8a which is thinner than the side portions on both sides. In the step portion 8a, each main region 1b of the Si film 1 is provided in a later step, and the base film 8 is formed.
The patterning is performed so that the length in the longitudinal direction is slightly shorter than that of each main region 1b provided on each of the above.

Next, the Si film 1 is formed on the base film 8 patterned in the above shape, and then the Si film 1 is formed.
Patterning is performed so as to have a shape having a plurality of rectangular main regions 1b having a constant width direction dimension and a plurality of end regions 1a continuously provided at one edge of each main region 1b. . The widthwise dimension of each end region 1a gradually decreases with distance from each main region 1b, and the widthwise dimension becomes 0 at the most end farthest from each main region 1b. Each main region 1b has a base film 8
Of the lower base film 8 is formed on the stepped portion 8a of the lower layer 8a, and a pattern is formed with a constant thickness so as to overlap the thicker portion of the underlying film 8 that is not formed. To be done. Therefore, in each main region 1b, the portion stacked on the step portion 8a is lower than the side edge portions. Further, each end region 1a of the Si film 1 is continuously provided to each main region 1b located in each step portion 8a formed in the base film 8, and therefore, the maximum dimension in the width direction is set. , The widthwise dimension of each stepped portion 8 is matched.

Then, the S thus patterned is formed.
A beam spot 2 having a V-shaped continuous shape similar to the beam spot 2 shown in FIG. The end regions 1a of the film 1 are aligned so as to irradiate the respective outermost ends thereof, and are orthogonal to the width direction of the Si film 1 from the respective end regions 1a as indicated by an arrow 3 in FIG. The Si film 1 which is in an amorphous or polycrystalline state is irradiated from the end regions 1a to the main regions 1 by irradiating while scanning in the direction.
Crystallization is carried out sequentially over b.

In the fourth embodiment, a plurality of step portions 8a are formed in the underlying film 8 below the Si film 1, and the respective side edges of each main region 1b of the Si film 1 are more than the central portion. The inventor of the present application has found that the crystal grain boundaries are generated only in the portion of the underlying film 8 stacked on the step portion 8a due to the height. Therefore, in the method for forming a semiconductor film according to the fourth embodiment, the position where the width is wide and the crystal grain boundary is generated is the main region 1b stacked on the step portion 8a of the base film 8. It is possible to form a crystalline Si film.

Next, a specific example of the fourth embodiment will be described.

First, similarly to the method of forming a semiconductor film according to the third embodiment described above, a SiO ₂ film as a base film 8 is formed to a thickness of 100 nm on an insulating substrate 7 such as a glass substrate. Then, RIE using CF ₄ gas and CHF ₃ gas
By the method, a plurality of step portions 8a having a depth of 50 nm are formed by etching into a predetermined shape. This step portion 8a
Is formed along each main region 1b of the Si film 1 provided on the SiO ₂ film which is the base film 8 in a later step, and has a dimension slightly longer than the main region 1b of the Si film 1 in the longitudinal direction. It is formed to be short.

Next, the Si film 1 which is a semiconductor film is formed to a thickness of 50 nm on the substrate 7 and the SiO ₂ film which is the base film 8 by the same method as in the third embodiment. The Si film 1 in this case is in an amorphous state. This Si
A partial region of the film 1 is etched by the RIE method using CF ₄ gas and O ₂ gas to form a plurality of main regions 1b having a constant width direction dimension and one end of each main region 1b. To form a plurality of continuous end regions 1a. Each end region 1a is provided continuously to the main region 1b portion on the base film 8, and the dimension in the width direction gradually decreases as the distance from the main region 1b increases.

Next, the Si film 1 is irradiated with a laser beam which is an energy beam to crystallize the amorphous Si film 1.

As shown in FIG. 5, this laser beam forms a plurality of beam spots 2 each having a substantially V-shaped continuous shape, and each concave non-heated region 2 of each beam spot 2.
The front part of a is aligned so as to irradiate the outermost portions of the respective end regions 1a of the Si film 1, and is orthogonal to the width direction of the respective main regions 1b from the respective end regions 1a of the Si film 1. Scan along the direction. In this case, the beam spot 2 is set to 0.5
Irradiate intermittently at intervals of μm. This beam spot 2
By the irradiation, the portion of the Si film 1 irradiated with the beam spot 2 is locally heated and melted. Then, the melted portion is crystallized so as to maintain the crystallinity continuing from the adjacent crystal region, and as a result, a single crystal crystal region grown along the scanning direction of the laser beam is formed.

Moreover, each main region 1b of the Si film 1 has a high side edge and a low center in the width direction.
The crystal grain boundaries are formed only in the portion where the height increases from the lowered central portion.

(Fifth Embodiment) FIG. 6 shows the fifth embodiment.
FIG. 3 is a perspective view showing a Si film patterned on a substrate and an energy beam for explaining the method of forming the semiconductor film of FIG.

In the method of forming a semiconductor film according to the fifth embodiment, an amorphous or polycrystalline semiconductor film 1 is provided on a non-single-crystal insulating film formed on a substrate or on a non-single-crystal insulating substrate, and thereafter. Then, the semiconductor film is patterned into a predetermined shape and irradiated with an energy beam to single crystallize the semiconductor film.

As shown in FIG. 6, the Si film 1 which is a semiconductor film provided on the substrate has a main region 1b formed in a rectangular shape with a constant width direction dimension, and one end of this main region 1b. And the end region 1a whose width dimension is 0 at the end farthest from the main region 1b. Is patterned into a shape having. Next, the antireflection film 10 is provided on both side edge portions of the main region 1b and the substrate 7 so that the central portion in the width direction of the main region 1b of the Si film 1 formed in such a pattern is exposed.

The S thus patterned is formed.
For the i film 1, the same V spot as the beam spot shown in FIG.
The character-shaped beam spot 2 is aligned so that the projecting portion located in the front in the scanning direction with respect to the concave non-heated region 2a is irradiated to the outermost end of the end region 1a of the Si film 1, As shown by the arrow 3 in FIG. 6, the end regions 1a to S
Irradiation is performed while scanning in a direction orthogonal to the width direction of the i film 1, and the amorphous or polycrystalline Si film 1 is sequentially single-crystallized from the end region 1a to the main region 1b.

In the fifth embodiment, the main region 1 of the Si film 1 is
SiO ₂ film 1 as an antireflection film corresponding to both sides of b
0 is provided, and the irradiation of the laser beam causes the temperature of the Si film 1 under the antireflection film 10 to be higher than that of the Si film 1 of the other portions, so that crystallization is delayed compared to the other portions. Therefore, the region where the crystal grain boundary is generated can be formed in the lower portion of the antireflection film 10 where crystallization is the last, and the position where the crystal grain boundary is generated is wide in the width direction and the antireflection film is formed. A crystalline Si film can be accurately formed in the region under 10.

Next, a specific example of the fifth embodiment will be described.

First, by using a method similar to the method of forming the semiconductor film of the third embodiment, the base film 8 of SiO 2 is formed on the substrate 7.
_Two films are formed with a film thickness of 50 nm. Then, a Si film 1 which is a semiconductor film is formed to a film thickness of 50 nm by a method similar to the method of forming a semiconductor film of the first embodiment, and the Si film 1 is etched to obtain a constant width. A main region 1b having a directional dimension and an end region 1a are formed by patterning continuously to one end of the main region 1b. The widthwise dimension of the end region 1a is gradually reduced with increasing distance from the main region 1b.

Next, a SiO ₂ film 10 serving as an antireflection film is formed to a thickness of 160 nm by a plasma CVD method using SiH ₄ gas and O ₂ gas, and then CF ₄ gas and C are used.
By the RIE method using HF ₃ gas, etching is performed so that the central portion in the width direction of the main region 1b of the Si film 1 is exposed.

Next, the Si film 1 is irradiated with a laser beam as an energy beam to crystallize the Si film 1 in an amorphous state.

This laser beam is approximately V on the Si film 1.
A beam-shaped beam spot is formed, and the front portion of the concave non-heated region 2a of the beam spot 2 is aligned so as to irradiate the outermost end of the end region 1a of the Si film 1, S
Scanning is performed in a direction orthogonal to the width direction of the main region 1b from the end region 1a of the i film 1. In this case, beam spot 2
Are intermittently irradiated at intervals of 0.5 μm. By the irradiation of the beam spot 2, the beam spot 2 of the Si film 1
The part irradiated with is locally heated and melted. Then, the melted portion is further crystallized so that it has crystallinity continuing from the adjacent crystal region, and as a result, a crystal region grown along the scanning direction of the laser beam is formed.

Moreover, the antireflection film 10 is formed on both side edges of the main region 1b of the Si film 1.
Since the temperature becomes higher than that in other regions where the antireflection film 10 is not formed and crystallization lags behind other regions, crystal grain boundaries are formed on both side edges of the main region 1b where the antireflection film 10 is provided.

(Sixth Embodiment) FIG. 7 shows a sixth embodiment.
FIG. 3 is a perspective view showing a Si film patterned on a substrate and an energy beam for explaining the method of forming the semiconductor film of FIG.

In the method of forming a semiconductor film according to the sixth embodiment, an amorphous or polycrystalline semiconductor film is provided on the non-single crystal insulating film formed on the substrate or on the non-single crystal insulating substrate,
After that, the semiconductor film is patterned into a predetermined shape and irradiated with an energy beam to single crystallize the semiconductor film.

As shown in FIG. 7, a Si film 1 which is a semiconductor film provided on a substrate has a plurality of main regions 1b formed in a rectangular shape with a constant width direction dimension and one of the main regions 1b. The main regions 1 are continuously provided at the end portions, and the widthwise dimension thereof gradually decreases as the distance from each main region 1b increases.
A pattern is formed in a shape having a plurality of end regions 1a having a dimension in the width direction of 0 at the most end portion farthest from b. Then, the antireflection film 10 is provided on both side edges of the main region 1b and on the substrate 7 so that the central portion in the width direction of each main region 1b of the Si film 1 formed in such a pattern is exposed.

Then, S patterned in this way is formed.
For the i film 1, the same V as the beam spot shown in FIG.
The beam spot 2 having a continuous V-shape is positioned so that the projecting portion located in front of the concave non-heated area 2a in the scanning direction is irradiated to the outermost end of each end area 1a of the Si film 1. Simultaneously, as shown by arrow 3 in FIG. 7, irradiation is performed while scanning from each end region 1a in a direction orthogonal to the width direction of the Si film 1, and the Si is in an amorphous or polycrystalline state.
The film 1 is sequentially single-crystallized from each end region 1a to each main region 1b.

In the sixth embodiment, the SiO 2 which is the antireflection film 10 corresponds to both sides of each main region 1b of the Si film 1.
_Two films are provided, and when the laser beam is irradiated, the Si film 1 under the antireflection film 10 is replaced with the Si film in the other part.
The temperature is higher than that of the film 1, and crystallization is delayed compared to other parts.
Therefore, the region where the crystal grain boundary is generated can be formed in the lower portion of the antireflection film 10 where crystallization is the last, and the position where the crystal grain boundary is generated is wide in the width direction and the antireflection film is formed. A crystalline Si film can be accurately formed in the region under 10.

Next, a specific example of the sixth embodiment will be described.

First, the base film 8 made of SiO 2 is formed on the substrate 7 by the same method as the semiconductor film forming method of the fourth embodiment.
_Two films are formed with a film thickness of 50 nm. Then, a Si film 1 which is a semiconductor film is formed to a film thickness of 50 nm by a method similar to the method of forming a semiconductor film of the first embodiment, and the Si film 1 is etched to obtain a constant width. A plurality of main regions 1b having directional dimensions and a plurality of end regions 1a are continuously formed on one end of each main region 1b by patterning. The widthwise dimension of each end region 1a becomes smaller as it goes away from the main region 1b.

Next, by a plasma CVD method using SiH ₄ gas and O ₂ gas, SiO to be the antireflection film 10 is formed.
After forming _two films to a thickness of 160 nm, CF ₄ gas and CH
By the RIE method using F ₃ gas, etching is performed so that the central portion of each main region 1b of the Si film 1 in the width direction is exposed.

Next, the Si film 1 is irradiated with a laser beam 2 as an energy beam to crystallize the Si film 1 in an amorphous state.

This laser beam is approximately V on the Si film 1.
A beam spot 2 having a continuous V-shape is formed.
The end portions 1a of the Si film 1 are aligned so as to irradiate the outermost portions of the end regions 1a, and the end regions 1a of the Si film 1 to the main regions 1 are aligned.
Scanning is performed along a direction orthogonal to the width direction of b. In this case, the beam spot 2 is intermittently irradiated at intervals of 0.5 μm. By the irradiation of the beam spot 2, the portion of the Si film 1 irradiated with the beam spot 2 is locally heated and melted. Then, the melted portion is further crystallized so that it has crystallinity continuing from the adjacent crystal region, and as a result, a crystal region grown along the scanning direction of the laser beam is formed.

Moreover, the antireflection film 10 is formed on both side edges of each main region 1b of the Si film 1.
Since the temperature becomes higher than that in other regions where 0 is not formed and crystallization is delayed compared to other regions, crystal grain boundaries are formed on both side edges of the main region 1b where the antireflection film 10 is provided.

(Seventh Embodiment) FIG. 8 shows the seventh embodiment.
FIG. 6 is a cross-sectional view showing the method of manufacturing the semiconductor device of FIG.

In the seventh embodiment, the above-described first embodiment is used.
A method for manufacturing a semiconductor device such as a thin film transistor using the semiconductor film described in any one of to 6 will be described. The semiconductor device manufactured by the manufacturing method according to the seventh embodiment can be used for a liquid crystal driver, a semiconductor memory, a semiconductor logic circuit and the like.

Hereinafter, a specific description will be given with reference to FIG.

First, on the glass substrate 11 on which the SiO ₂ film 12 is formed with a film thickness of 50 nm, the above-described first to _third embodiments are formed.
6. A crystalline Si film having a film thickness of 50 nm is formed by the method for forming a semiconductor film according to any one of 6 above, and subsequently, this crystalline Si film is subjected to an RIE method using CF ₄ gas and O ₂ gas. Patterning into a predetermined shape by means of island-shaped crystalline Si
The film 13 is formed. After that, plasma CV using TEOS (tetraethoxysilane) gas and O ₃ gas is applied over the entire surface of the substrate on which the crystalline Si film 13 is formed.
The gate SiO ₂ film 14 is formed by the D method.

Next, by sputtering, W is formed over the entire surface of the substrate on which the gate SiO ₂ film 14 is formed.
After forming the Si ₂ layer, R using CF ₄ gas and O ₂ gas
By the IE method, the WSi ₂ polycrystalline gate electrode 15 is formed by etching such that the WSi ₂ layer is left only in the substantially central portion of the crystalline Si film 13.

Next, impurities are introduced on the crystalline Si film 13 to form the source / drain regions of the thin film transistor. In the case of the seventh embodiment, the WSi ₂ polycrystal gate electrode 15 serves as a mask for introducing impurities, and the crystalline Si film 13 is formed on the crystalline Si film 13 other than the portion where the WSi ₂ polycrystal gate electrode 15 is provided. Impurities are introduced. When forming an n-type transistor, the introduced impurity is phosphorus (P), and when forming a p-type transistor, the introduced impurity is boron (B).

Next, by the plasma CVD method using TEOS gas and O ₃ gas, S is deposited over the entire surface of the substrate.
After forming the iO ₂ film 16, a contact hole is formed on the crystalline Si film 13 to be the source / drain regions by the RIE method using CF ₄ gas and CHF ₃ gas.

Next, the surface of the substrate is sputtered using the sputtering method.
After laminating Al on the entire surface, BCl₃Gas and Cl₂With gas
According to the RIE method used, the gate SiO₂Membrane 14 and S
iO ₂Connection through the contact hole formed in the film 16
The Al wiring 17 is electrically connected to the crystalline Si film 13.

Next, SiH ₄ gas, NH ₃ gas and N ₂
A SiN protective film 18 is formed on the entire surface of the substrate by a plasma CVD method using a gas, and finally SiN is formed.
A part of the protective film 18 is etched by using CF ₄ gas and CHF ₃ gas to open a window so as to be electrically connected to a part on one side of the Al wiring 17, and the thin film transistor is completed.

(Embodiment 8) FIG. 9 shows the eighth embodiment.
FIG. 6 is a cross-sectional view showing a method of manufacturing a display device using the semiconductor device of FIG.

The eighth embodiment is the same as the seventh embodiment.
A method of manufacturing a display device such as a liquid crystal display device using a semiconductor device manufactured by the same method as described above will be described.

The eighth embodiment will be described below with reference to FIG.
This will be described with reference to (a) and (b).

First, the semiconductor device is manufactured on the insulating substrate 11 made of glass or the like by the manufacturing method of the seventh embodiment.
It should be noted that each component of the semiconductor device formed on this insulating substrate 11 is denoted by the same reference numeral as in the seventh embodiment, and detailed description thereof is omitted.

Next, the SiO ₂ film 19 of 300 n is formed over the entire insulating substrate on which the semiconductor device is formed by the plasma CVD method using TEOS gas and O ₃ gas.
It is formed to a film thickness of m.

Next, R using CF ₄ gas and CHF ₃ gas was used.
A through hole reaching the Al wiring 17 of the semiconductor device is formed by the IE method.

Next, SiO 2 is formed by a sputtering method.
_The ITO film is formed over the entire surface of the substrate on which the ₂ film 19 is formed, and subsequently, etching is performed by using HCl and FeCl ₃ gas to etch the semiconductor device through the through hole formed in the SiO ₂ film 19. Al wiring 17
The pixel electrode 20 that is electrically connected to is formed to a film thickness of 500 nm.

Next, the SiN protective film 21 is formed to a thickness of 400 nm over the entire surface of the substrate by the plasma CVD method using SiH ₄ gas, NH ₃ gas and N ₂ gas. Further, a polyimide film 22 serving as an alignment film is formed on the SiN protective film 21 by an offset printing method,
Perform rubbing treatment.

On the other hand, as shown in FIG. 9 (b), a film on which another photosensitive resin film of R (red), G (green) and B (blue) is attached is thermocompression-bonded on another glass substrate 23. Patterning is performed by a photolithography process, and a black matrix portion having a light-shielding property is formed between the portions where the R, G, and B photosensitive resins are transferred, and the color filter 24 is formed. To make.

On this color filter 24, an ITO film is formed over the entire surface of the substrate by a sputtering method to form a counter electrode 25. Further, a polyimide film 26 which is an alignment film is formed on the counter electrode 25 by an offset printing method, and a rubbing process is performed.

The glass substrate 23 on which the color filter 24 shown in FIG. 9B formed as described above is formed, and the glass substrate 11 on which a semiconductor device such as a thin film transistor shown in FIG. 9A is formed, The rubbing-treated surfaces are arranged so as to face each other, and they are bonded together by a sealing resin. At this time, pearly silica is sprinkled between the glass substrates so that the space between the two glass substrates is constant. Then, after injecting liquid crystal serving as a display medium between both substrates, a polarizing plate or the like is attached to both outer sides of both glass substrates, and peripheral ICs or the like are mounted to complete the liquid crystal display device.

In the semiconductor film forming methods of the above-described first to sixth embodiments, a method of forming a Si film is shown as a specific example of the semiconductor film to be formed. , Si film, SiGe film, GaAs
It can also be applied to the case of forming a film, InP or the like.

Further, in the above-described first to sixth embodiments, the method of irradiating the laser beam as the energy beam for applying the thermal energy for melting the amorphous semiconductor film is used. Alternatively, the shaped light shaped so that the concave non-heated region is formed, or the point-like light obtained by condensing the point-like light may be scanned at high speed and irradiated.

Further, when the antireflection film as described in the fifth and sixth embodiments is not formed, the shaped charged particles or the point-like charged particle beam may be scanned in a line at a high speed and irradiated. good.

Further, in the above embodiment, the laser beam was intermittently irradiated at intervals of 0.5 μm, but this interval can be appropriately selected within the range of 0.1 to 10 μm.

[0116]

According to the method of forming a semiconductor film of the present invention, a semiconductor film in an amorphous or polycrystalline state formed on a substrate is formed into a main region having a constant width direction and one of the main regions. From the end portion of the semiconductor film is patterned into a shape having an end region whose widthwise dimension is successively reduced, and with respect to this semiconductor film, a beam spot having a concave non-heated region on the rear side with respect to the scanning direction is formed. The formed energy beam,
The front portion of the concave non-heated region formed in the beam spot is aligned so that it is irradiated to the outermost portion of the end region of the semiconductor film, and in the direction from the end region of the semiconductor film toward the main region. Since the scanning is performed, the crystal growth proceeds using the crystal nuclei generated at the outermost end of the end region as a seed, and the temperature distribution of the semiconductor film irradiated with the energy beam is high in the irradiation region, and the temperature becomes slightly lower during that period. Even if the generated energy distribution causes a temperature fluctuation in the irradiated energy beam, it is possible to prevent the generation of irregular crystal nuclei due to the temperature fluctuation.

If a semiconductor film is formed with a plurality of main regions and a plurality of end regions at one end of each main region, and the main regions are formed in a continuous pattern, the outermost end of each end region is formed. Each crystal region grown as a seed crystal using the crystal nuclei generated in step clashes at the part where the main regions are in contact with each other, and a grain boundary is generated in this part. Can be controlled.

Therefore, by using the method for forming a semiconductor film of the present invention, a wide band-shaped single crystal semiconductor film or a crystalline semiconductor film in which single crystal regions are regularly arranged in columns can be obtained. it can. With such a semiconductor film having good crystallinity, a high-quality semiconductor device and further a display device can be manufactured.

[Brief description of drawings]

FIG. 1 is a schematic plan view illustrating a method of forming a semiconductor film according to a first embodiment.

2A is a plan view showing a beam spot of an energy beam used in the method for forming a semiconductor film according to the first embodiment, and FIG. 2B is a sectional view taken along line AA ′ in FIG. The beam intensity, in (c), shows the temperature distribution of the semiconductor film 1 along the line AA '.

FIG. 3 is a schematic plan view showing a method for forming a semiconductor film according to a second embodiment.

FIG. 4 is a perspective view showing a method of forming a semiconductor film according to a third embodiment.

FIG. 5 is a perspective view showing a method of forming a semiconductor film according to a fourth embodiment.

FIG. 6 is a perspective view showing a method for forming a semiconductor film according to a fifth embodiment.

FIG. 7 is a perspective view showing a method for forming a semiconductor film according to a sixth embodiment.

FIG. 8 is a sectional view showing a semiconductor device according to a seventh embodiment.

9A and 9B are cross-sectional views showing a substrate constituting a liquid crystal display device of Embodiment 8, wherein FIG. 9A shows a substrate on which a semiconductor device is formed, and FIG. 9B shows a substrate on which a counter electrode is provided. There is.

FIG. 10 is a plan view for explaining a method for forming a semiconductor film of Conventional Example 1.

FIG. 11 is a plan view for explaining a method for forming a semiconductor film of Conventional Example 2.

[Explanation of symbols]

1 Si film 2 Beam spot 3 Energy beam scanning direction 7 Substrate 8 Underlayer film 10 Antireflection film 11 Glass substrate 12 Underlayer film 13 Crystalline Si film 14 Gate SiO ₂ film 15 WSi ₂ polycrystalline gate electrode 16 SiO ₂ film 17 Al Wiring 18 SiN protective film 19 SiO ₂ film 20 Pixel electrode 21 SiN protective film 22 Polyimide film 23 Glass substrate 24 Color filter 25 Counter electrode 26 Polyimide film

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2H092 KA04 KA05 MA29 MA30 NA24                 5F052 AA02 BA08 BA09 CA04 DA02                       DA03 DA05 DB02 EA07 FA02                       FA12 FA13 FA27 JA01                 5F110 AA30 BB01 CC02 DD02 DD13                       EE05 EE44 FF02 FF30 GG01                       GG02 GG04 GG13 GG23 GG25                       GG47 HJ01 HL03 HL23 NN03                       NN23 NN24 NN35 PP03 PP05                       PP06 PP08 QQ11

Claims (11)

[Claims] 1. An amorphous or polycrystalline semiconductor film formed on a substrate is irradiated with an energy beam which gives thermal energy for melting the semiconductor film while scanning the semiconductor film in a certain direction. A method of forming a semiconductor film to be crystallized, the semiconductor film comprising: a main region having a constant width direction dimension;
A pattern is formed on the substrate so as to have one end portion of the main region, the end region being continuously provided so that the widthwise dimension becomes gradually smaller as the distance from the main region increases, The energy beam is given by a beam spot having a concave non-heated region at the rear part with respect to the scanning direction, and the front part of the concave non-heated region in the beam spot is irradiated to the outermost part of the end region of the semiconductor film. A method for forming a semiconductor film, which comprises performing the alignment as described above and scanning the beam spot from the end region of the semiconductor film toward the main region. 2. The patterned semiconductor film has a plurality of main regions and a plurality of end regions continuous with the respective main regions, and the beam spot has a plurality of beam spots corresponding to the respective end regions. The method for forming a semiconductor film according to claim 1, wherein the concave non-heated region is formed. 3. Before forming a pattern of the semiconductor film on a substrate, a base film having a step portion in which a portion corresponding to a central portion in the width direction of the main region is lowered is provided, and a width of the main region is formed. The method for forming a semiconductor film according to claim 1, wherein the central portion in the direction is formed lower than the side edge portions. 4. The method for forming a semiconductor film according to claim 3, wherein the end region is formed continuously with a central portion of a main region provided on the step portion. 5. The semiconductor film according to claim 1, wherein an antireflection film is provided on both side portions of the main region of the semiconductor film before being irradiated with the energy beam, except for the central portion in the width direction. Forming method. 6. The method for forming a semiconductor film according to claim 1, wherein the semiconductor film is a silicon film. 7. The method for forming a semiconductor film according to claim 1, wherein the energy beam is a laser beam. 8. The method of forming a semiconductor film according to claim 1, wherein the energy beam is shaping light or point light shaped so that the concave non-heated region is provided. . 9. The laser beam is 0.1 μm to 1 μm.
The method for forming a semiconductor film according to claim 7, wherein irradiation is performed intermittently at intervals of 0 μm. 10. A semiconductor device having a semiconductor film formed by the method for forming a semiconductor film according to claim 1. 11. A display device comprising the semiconductor device according to claim 10.