JP2003309068A - Semiconductor film and forming method therefor, and semiconductor device and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for forming a crystalline semiconductor film in simple processes. <P>SOLUTION: This method for forming a crystalline semiconductor film comprises a process for forming a semiconductor film, a process for forming heating/cooling control film wherein a heating/cooling control film is so formed thickly as to have a cap region melting energy larger than a bare region melting energy, a first irradiation process wherein irradiation with a first laser beam is performed with an energy larger than the cap region melting energy, a cap region crystallizing process wherein a cap region semiconductor film is crystallized based on a bare region semiconductor film, a second irradiation process wherein irradiation with a second laser beam is performed with an energy that is larger than the bare region melting energy and smaller than the cap region melting energy, a bare region crystallizing process wherein the bare region semiconductor film is crystallized based on the cap region semiconductor film, and a removing process wherein the heating/cooling control film is removed from the semiconductor film. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a crystalline semiconductor film obtained by crystallizing an amorphous semiconductor film formed on an amorphous insulating substrate, a method for forming the crystalline semiconductor film, and a semiconductor using the semiconductor film. More specifically, the present invention relates to a device and a method for manufacturing the same, in which thermal energy is applied to an amorphous semiconductor film formed on an amorphous insulating substrate by applying laser light to crystallize the amorphous semiconductor film. The present invention relates to a crystalline semiconductor film obtained by the method, a method for forming the crystalline semiconductor film, a semiconductor device using the semiconductor film, and a method for manufacturing the semiconductor device.

[0002]

2. Description of the Related Art An amorphous semiconductor thin film is formed on an amorphous substrate or an amorphous insulating film, heat energy is locally applied to the semiconductor thin film to melt it, and the melted portion is crystallized. A method of manufacturing a semiconductor film by converting it into a crystalline semiconductor film has a history of nearly 30 years of research. inside that,
A method of irradiating an amorphous semiconductor film with laser light as a heat energy source has been studied to form an SOI substrate in the 1980s, and since the 1990s, a liquid crystal panel is manufactured by a low temperature polysilicon technology. It has been used for method development and mass production, and can be said to be the most proven method. In particular, when an inexpensive substrate such as a glass substrate that cannot withstand a high temperature process is used, it is necessary to apply thermal energy within an extremely short time. The only way is to use a laser.

IEEE Electron Dev. L
ett. , EDL-7, 276, 1986 (Samejima et al., Reference 1) discloses a method of irradiating an amorphous silicon thin film formed on a glass substrate with a high-power excimer laser for crystallization. There is. The crystallization method of the amorphous silicon thin film disclosed in Document 1 was started by Samejima et al., And in this Document 1, the energy density of the laser beam with which the amorphous silicon thin film is irradiated is , A value such that the upper part of the silicon thin film is partially melted. In subsequent studies, the relationship between the energy density of the irradiated laser light and the crystal grain size of the formed crystalline semiconductor film was investigated in detail, and when the energy density of the laser light increased, the crystal grain size increased accordingly. Has been revealed to increase.

Regarding such increase in crystal grain size,
J. Appl. Phys. 82, 4086 (reference 2). According to this document 2, in particular, the depth at which the amorphous semiconductor film is melted by the irradiation of the laser light is immediately before the film thickness of the silicon thin film, that is,
It has been reported that huge crystal grains of several microns are formed when the silicon thin film is about to be melted to the interface reaching the underlying substrate or the like. This is because the crystal grains slightly remaining at the interface with the lower layer of the silicon thin film are
This is because it becomes a crystal nucleus at the time of starting the solidification of the crystal, and it becomes possible to grow crystal grains having a large grain size.

However, in the crystallization method described in Reference 2, when the energy density of the laser beam exceeds the value which is melted just before the interface of the silicon thin film and is completely melted until reaching the lower layer of the silicon thin film. A rapid cooling process occurs, random nucleation occurs, the crystal grains become very small, or re-amorphization occurs. Therefore, in practice, in consideration of the fluctuation of the output of the laser light, the irradiated laser light is set to an energy of a value slightly smaller than the energy density at which complete melting occurs. Therefore, the grain size of the obtained crystal grain is about several hundreds nm depending on the laser light irradiation conditions. Under the laser light irradiation conditions based on Document 2, mass production is currently being performed as a low-temperature polysilicon forming technique. A typical carrier mobility of a TFT manufactured based on the technique of Document 2 is an n-channel TFT.
Then, 150 cm ² / Vs, p-channel type channel TF
80 cm ² / Vs is obtained at T.

When a liquid crystal panel having a semiconductor device using a polysilicon semiconductor film crystallized by irradiation with pulsed laser light as described above is realized, the semiconductor thin film of polysilicon is made to have higher performance and further increase in number. There is an increasing demand to realize an active matrix TFT substrate in which functional circuit elements are integrated.

In response to such a demand, the amorphous silicon film is completely melted at the time of crystallization by irradiating a laser beam, and the generation of random nuclei during crystallization is suppressed, A method for obtaining TFT characteristics comparable to a single crystal substrate by controlling lateral growth has been reported.

At the research stage level, a wide variety of methods have been proposed, but these are methods in which a partially melted region is present in a silicon thin film so as to be in contact with a completely melted region, and partially melted. It is common as a basic idea that the crystal nuclei existing in the formed region serve as nuclei when the melted silicon film in the completely melted region starts to crystallize. Hereinafter, two methods will be described as examples of methods applicable to a practical level.

As a first method, a laser beam having an extremely high aspect ratio is formed, a semiconductor film in an irradiation region irradiated with this laser beam is completely melted, and then a laser beam adjacent to the irradiation region of the laser beam is formed. A method for inducing lateral crystal growth from a crystalline semiconductor film existing in a non-irradiated region is described in Appl.
Phys. Lett 691 (19), 4 Novem
ber 1996 (reference 3). In this method, laser light is grown in one direction along the scanning direction of the laser light by irradiating while scanning a region shifted by a distance approximately equal to the distance at which crystals can grow laterally by one melting. Fine crystal grains are obtained. From this, this crystallization method is described in J. Im et al., SLS (Sequential Latera)
l Solidification).

When this first method is used, there is an advantage that crystal grains of an arbitrary length can be formed on the entire surface without any gap.

As a second method, a method of forming an aluminum film, which is a beam reflecting film, in a stripe shape on an amorphous silicon thin film is an IEEE Elctron Devi method.
ceMeeting, San Frncisco (Reference 4).

FIG. 18 (a) is a sectional view showing the crystal growth method described in Document 4, and FIG. 18 (b) is a plan view of a crystalline semiconductor film obtained by this method.

In the method of Document 4, as shown in FIG. 18A, an amorphous silicon thin film (hereinafter also referred to as “a-Si film”) 2 formed on the surface of the insulating glass substrate 5 is used.
When irradiating the laser beam over the entire upper surface,
In the region 95 where the beam reflection film 91 is not provided, the amorphous silicon film is completely melted by the irradiation of the laser light because it is exposed to the irradiated laser light. And the beam reflection film 9
In the region 96 where 1 is provided, the amorphous silicon film 2 is an unmelted portion that is not melted because the laser light is not irradiated. The completely melted portion and the unmelted portion are arranged so as to be adjacent to each other repeatedly because the beam reflection film 91 is provided in a stripe shape. The silicon melted in the completely melted region 95 undergoes lateral crystal growth based on the crystal nuclei existing in the unmelted region 96, and as a result, as shown in FIG. Crystal growth is performed from both end sides in contact with the unmelted region 96 toward the central portion of the molten region 95, and crystal grains are formed in a shape in which the respective crystal grains collide with each other at the substantially central portion.

Also, the AM-LCD 2000 Dige
st, p281 (Reference 5) describes a method of forming a region that is partially thick in a silicon thin film, instead of providing a beam reflecting film. In the method of Document 5, the thinly formed portion of the silicon thin film is a completely melted portion, and the thickly formed portion is a partially melted portion that is partially melted. Then, the silicon thin film completely melted in the completely melted portion undergoes crystal growth in the lateral direction based on the crystal nucleus existing in the partially melted portion.

In these second methods, a laser is formed by patterning a reflection film on a silicon thin film into a desired shape, or by patterning a region formed in a thick film on the silicon thin film into a desired shape. Advantages that the crystal grain extension direction can be determined regardless of the beam scanning direction, and silicon films whose crystal grain extension directions are orthogonal to each other can be formed mixedly on the same substrate. There is.

However, in the above first and second methods,
There are problems as described below.

First, in the first method, the length of lateral growth in which crystal grains grow by one irradiation of laser light is
Since it becomes as fine as 0.5 to 4 μm, it is necessary to scan the laser beam with high precision in accordance with this length, and as a result, the processing time for crystallization becomes long and the laser beam It is necessary to prepare a device with a special structure for irradiation. Further, according to the first method, extremely elongated crystal grains elongated in the scanning direction of the laser beam can be obtained, and when a TFT is constituted by a crystalline silicon film having such crystal grains, the channel of the TFT is In the case where the carrier flow direction and the crystal grain extension direction coincide with each other, the carrier mobility is extremely high, but when the carrier flow direction is orthogonal to the crystal grain extension direction, the carrier is It is known that the mobility of carriers deteriorates to about ⅓ as compared with the case where the flowing direction and the extending direction of crystal grains are the same.
In this method, the direction in which crystal grains grow is determined by the scanning direction of the laser beam, so high characteristics can be obtained only in one direction, and crystal grains that extend in other directions should be mixed on the same substrate. I can't. Therefore, this method is not preferable due to restrictions in designing circuit elements.

On the other hand, in the second method, the length of the crystal grain is
There is a problem that it is limited to one lateral growth distance.In addition, in this crystallization method, crystal growth is started based on the crystal nuclei remaining in the unmelted region, so that it is adjacent to the melted region at a predetermined interval. It is necessary to form an unmelted area for each.
If the unmelted portion is formed too finely so that the crystal grains laterally grown in the completely melted portion are as close as possible to the crystal grains of the other completely melted portions that are adjacent to each other across the unmelted portion, Since the initial nuclei of the unmelted part required at the start of crystal growth may disappear by laser light irradiation and minute crystal nuclei may be formed by random nucleation, the unmelted part is formed to a certain size. There is a need. Therefore, this crystallization method has a problem that the element size increases due to the area required to form the unmelted portion.

A structure for solving such a problem is
It is disclosed in Japanese Patent Application No. 2001-292538. Figure 1
9 and 20 are cross-sectional views illustrating another conventional method for forming a crystalline semiconductor film.

Referring to FIG. 19, first, the glass substrate 5
A base coat film 6 is formed on top. Then, the a-Si film 2 is formed on the base coat film 6. Then a-S
A plurality of antireflection films 92 are formed in stripes on the i film 2 at regular intervals. Next, the reflection film 93 is laminated on each antireflection film 92.

Then, the a-Si film 2 is irradiated with the first laser beam from the reflective film 93 side. Bare region a-Si film 4 between antireflection films 92 not covered by antireflection film 92
Is completely melted by the first irradiation of laser light. The cap area a− covered with the antireflection film 92
The Si film 3 does not melt because the reflection film 93 reflects the first laser beam. The bare region a-Si film 4 completely melted by the first irradiation of the laser beam is covered with the antireflection film 92, and therefore the bare region a-Si film 3 is not melted and the bare region a-Si film 4 is used as a core. -S
Lateral growth is performed from both ends of the i film 4 toward the center of the bare region a-Si film 4 to form crystal grains.

Referring to FIG. 20, next, the reflection film 93 is removed. Then, from the antireflection film 92 side, the a-Si film 2
To the second laser beam. Reflection of the irradiated second laser beam is prevented by the antireflection film 92, and the cap region a-Si film 3 covered with the antireflection film 92 is completely melted. Completely melted cap area aS
The i film 3 laterally grows from both sides of the cap region a-Si film 3 toward the center with the crystal grains in the bare region a-Si film 4 formed when the first laser beam is irradiated as nuclei, Crystal grains are formed.

As described above, according to the above-mentioned conventional technique, it is possible to form a crystal grain having a length twice as long as the lateral growth distance once without forming a gap and to increase the element size. Instead, crystal streams extending along different directions can be formed on the same substrate.

[0024]

However, in the above-mentioned conventional technique described above with reference to FIGS. 19 and 20, the process is complicated because the reflection film 93 must be further laminated on the antireflection film 92. However, there is a problem that the cost increases.

Since the reflection film 93 further laminated on the antireflection film 92 must be removed after the first laser light irradiation and before the second laser light irradiation, the laser device is removed. The glass substrate 5 is taken out and the reflection film 9
3 must be removed and the glass substrate 5 from which the reflection film 93 has been removed must be set again in the laser device. Therefore, there is a problem that the process is further complicated and the cost is further increased.

Further, when the first laser beam is irradiated, the reflection film 93 made of metal melts and flows down onto the bare region a-Si film 4, or the reflection film 93 evaporates and vaporizes to leave the bare film. Since the a-Si film 2 is contaminated because it adheres to the region a-Si film 4, the characteristics of a thin film transistor (hereinafter also referred to as “TFT”) manufactured using such a crystalline semiconductor film deteriorates. However, there is a problem that variations in characteristics increase.

The present invention has been made to solve such a problem, and an object thereof is a method for forming a crystalline semiconductor film and a crystalline semiconductor film, which are simple in process, and a method for manufacturing a semiconductor device and a semiconductor. To provide a device.

Another object of the present invention is to provide a method for forming a crystalline semiconductor film and a crystalline semiconductor film which are low in cost, a method for manufacturing a semiconductor device and a semiconductor device.

[0029]

A method of forming a crystalline semiconductor film according to the present invention is a method of forming a crystalline semiconductor film by crystallizing a semiconductor film, wherein the semiconductor film is formed on an insulating substrate. A semiconductor film forming step, a heating / cooling suppressing film forming step of forming a plurality of heating / cooling suppressing films each having a predetermined film thickness on the semiconductor film and having a predetermined thickness in a stripe pattern at regular intervals, and the heating / cooling step. A first laser beam is irradiated from the heating / cooling suppression film side to the semiconductor film so that the cap region semiconductor film covered with the suppression film and the bare region semiconductor film not covered with the heating / cooling suppression film are completely melted. After the irradiation step, the cap area crystallization step of crystallizing the completely melted cap area semiconductor film based on the bare area semiconductor film, and the bare area semiconductor film after the cap area crystallization step. The irradiation with the second laser beam so only completely melted from the heating cooling suppression film side to the semiconductor film 2
An irradiation step, a bare area crystallization step of crystallizing the completely melted bare area semiconductor film based on the cap area semiconductor film, and a removal step of removing the heating / cooling suppression film from the semiconductor film are included. The above object is achieved by that.

The predetermined thickness of each heating / cooling suppressing film is set such that the cap region complete melting energy required to completely melt the cap region semiconductor film is the bare region required to completely melt the bare region semiconductor film. The film thickness is larger than the complete melting energy, the first laser light has an energy larger than the cap region complete melting energy, and the second laser light is the bare region complete melting energy. May have an energy greater than and less than the cap region full melting energy.

The first and second laser lights have wavelengths λ, respectively, and the thickness of the heating / cooling suppressing film is (3λ), where n is the refractive index of the heating / cooling suppressing film.
/ (8n) or more may be set.

The heating / cooling suppressing film may be composed of a silicon oxide film.

The heating / cooling suppressing film may be composed of any one of a silicon nitride film and a laminated film of a silicon oxide film and a silicon nitride film.

In the cap region semiconductor film crystallized in the cap region crystallization step, the semiconductor crystal grains forming the cap region semiconductor film are in contact with the bare region semiconductor film adjacent to the cap region semiconductor film. It is crystallized by lateral growth from both ends of the semiconductor film toward the center of the cap region semiconductor film,
In the bare region semiconductor film crystallized in the bare region crystallization step, the semiconductor crystal grains forming the bare region semiconductor film are in contact with the adjacent cap region semiconductor film. May be crystallized by lateral growth from both ends toward the center of the bare region semiconductor film.

The crystalline semiconductor film according to the present invention is formed by the method for forming a crystalline semiconductor film according to the present invention, thereby achieving the above object.

A method of manufacturing a semiconductor device according to the present invention is a method of manufacturing a semiconductor device in which a crystalline semiconductor film obtained by crystallizing a semiconductor film is used as a channel region, and the semiconductor film is formed on an insulating substrate. A semiconductor film forming step, a heating / cooling suppressing film forming step of forming a plurality of heating / cooling suppressing films each having a predetermined film thickness on the semiconductor film and having a predetermined thickness in a stripe pattern at regular intervals, and the heating / cooling step. A first laser beam is irradiated from the heating / cooling suppression film side to the semiconductor film so that the cap region semiconductor film covered with the suppression film and the bare region semiconductor film not covered with the heating / cooling suppression film are completely melted. After the irradiation step, the cap area crystallization step of crystallizing the completely melted cap area semiconductor film based on the bare area semiconductor film, and the cap area crystallization step, A second irradiation step of irradiating the semiconductor film with a second laser beam so that only the bare region semiconductor film is completely melted, and the completely melted bare region semiconductor film is applied to the cap region semiconductor film. The present invention is characterized in that it includes a bare region crystallization step of crystallizing based on this, and a removal step of removing the heating / cooling suppression film from the semiconductor film, whereby the above object is achieved.

Another method of manufacturing a semiconductor device according to the present invention is a method of manufacturing a semiconductor device in which a crystalline semiconductor film obtained by crystallizing a semiconductor film is used as a channel region, and the semiconductor film is formed on an insulating substrate. A step of forming a semiconductor film,
A plurality of first heating / cooling suppressing films each having a predetermined film thickness that are equal to each other in the first region on the semiconductor film are formed in stripes at regular intervals, and in the second region on the semiconductor film. A heating / cooling suppression film forming step of forming a plurality of second heating / cooling suppression films each having a predetermined film thickness along the direction intersecting with the first heating / cooling suppression film in stripes at regular intervals. So that the cap region semiconductor film covered by the first and second heating / cooling suppressing films and the bare region semiconductor film not covered by any of the first and second heating / cooling suppressing films are completely melted. A first irradiation step of irradiating the semiconductor film with a first laser beam from the first and second heating / cooling suppression film sides, and crystallizing the completely melted cap region semiconductor film based on the bare region semiconductor film. After the cap region crystallization step and the cap region crystallization step, a second laser beam is applied to the semiconductor film from the first and second heating / cooling suppression film sides so that only the bare region semiconductor film is completely melted. A second irradiation step of irradiating the bare region semiconductor film, a bare region crystallization step of crystallizing the completely melted bare region semiconductor film based on the cap region semiconductor film, and the first and second heating / cooling suppressing films A removal step of removing from the film is included, whereby the above object is achieved.

The semiconductor device according to the present invention is manufactured by the method for manufacturing a semiconductor device according to the present invention, whereby the above object is achieved.

The semiconductor film of the present invention is characterized in that part of the crystal grain boundaries of the laterally grown semiconductor crystal grains is in contact with the amorphous semiconductor film.

In the semiconductor film of the present invention, the laterally grown semiconductor crystal grains are in contact with each other at the crystal grain boundary, and the distance between adjacent crystal grain boundaries is not more than twice the distance at which the semiconductor crystal grains grow laterally. It is characterized by being.

In the semiconductor device of the present invention, a crystalline semiconductor film in which semiconductor crystal grains are laterally grown along the surface of the amorphous insulating substrate is provided on the amorphous insulating substrate. A semiconductor device having a crystalline semiconductor film as an active region, wherein the crystalline semiconductor film is characterized in that part of crystal grain boundaries of laterally grown semiconductor crystal grains is in contact with the amorphous semiconductor film. To do.

In the semiconductor device of the present invention, a crystalline semiconductor film in which semiconductor crystal grains are laterally grown along the surface of the amorphous insulating substrate is provided on the amorphous insulating substrate, A semiconductor device comprising the crystalline semiconductor film as an active region, wherein the laterally grown semiconductor crystal grains are in contact with each other at a crystal grain boundary, and the distance between adjacent crystal grain boundaries is small. It is characterized in that the distance is not more than twice the lateral growth distance of the semiconductor crystal grains.

A plurality of regions are provided in which the lateral growth directions of the semiconductor crystal grains are orthogonal to each other.

[0044]

BEST MODE FOR CARRYING OUT THE INVENTION In the method for forming a crystalline semiconductor film according to this embodiment, a polycrystalline silicon film is formed on a glass substrate.

(Embodiment 1) FIG. 1 is a cross-sectional view illustrating a step of forming an amorphous silicon film in the method for forming a crystalline semiconductor film according to Embodiment 1. First, the base coat film 6 made of a silicon oxide film is formed on the glass substrate 5 by P-CVD to a thickness of 300 n.
It is formed to a thickness of m. The glass substrate 5 is Turnin
g1737. Then, the a-Si film 2 is formed on the base coat film 6 by the P-CVD method.
It is formed to a thickness of nm. Next, the glass substrate 5 on which the a-Si film 2 and the base coat film 6 are formed is heated at 500 ° C. for 1 hour in a nitrogen atmosphere in an electric furnace to dehydrogenate the a-Si film 2.

FIG. 2 is a sectional view for explaining a step of forming a heating / cooling suppressing film in the method for forming a crystalline semiconductor film, and FIG. 3 is a perspective view thereof. Dehydrogenated a-
A silicon oxide film is formed on the Si film 2 by the P-CVD method. Then, the silicon oxide film formed on the a-Si film 2 is patterned by etching using the BHF 110 to form a plurality of heating / cooling suppressing films 1 having a film width of 2 microns in stripes at intervals of 2 microns. Form.

Here, the a-Si film 2 in the region covered by the heating / cooling suppressing film 1 is referred to as a cap region a-Si film 3, and the space between the heating / cooling suppressing film 1 not covered by the heating / cooling suppressing film 1 is called. The a-Si film 2 is replaced with the bare region a-Si film 4
I will call it.

FIG. 4 is a graph showing the relationship between the film thickness of the heating / cooling suppressing film and the cap region complete melting energy.
The horizontal axis represents the heating / cooling suppression film 1 formed on the a-Si film 2.
Of the laser energy necessary to completely melt the cap region a-Si film 3 covered with the heating / cooling suppression film 1 formed of a silicon oxide film (hereinafter referred to as “cap region”). Complete melting energy "
It means that).

Since the reflectance of the heating / cooling suppressing film 1 changes depending on the film thickness, the energy of the laser light reaching the cap region a-Si film 3 covered with the heating / cooling suppressing film 1 is equal to that of the heating / cooling suppressing film 1. It changes depending on the film thickness. Therefore, the cap region complete melting energy changes depending on the film thickness of the heating / cooling suppression film 1. The cap region complete melting energy changes in a cosine curve with respect to the film thickness of the heating / cooling suppressing film 1, reflecting the change of the reflectance of the heating / cooling suppressing film 1 with respect to the film thickness.

When the heating / cooling suppressing film 1 is made of a material having a large heat capacity such as a silicon oxide film, the heating / cooling suppressing film 1 in the energy of the irradiated laser light increases as the film thickness of the heating / cooling suppressing film 1 increases. The energy that is absorbed by and increases in the temperature of the heating / cooling suppression film 1 increases. Therefore, as shown in FIG. 4, the cap region complete melting energy that changes in a cosine curve shape is represented by a curve that increases to the right as the thickness of the heating / cooling suppressing film 1 increases. The cap region complete melting energy represented by the upwardly rising curve completely melts the bare region a-Si film 4 which is not covered by the heating / cooling suppressing film 1 as the thickness of the heating / cooling suppressing film 1 increases. The laser energy required for this purpose (hereinafter referred to as "bare region complete melting energy") may be exceeded.

As described above, the condition for the cap region complete melting energy to be larger than the bare region complete melting energy is that the film thickness d of the heating / cooling suppressing film 1 is (3λ) /
(8n) or more. Here, λ is the wavelength of the laser light to be irradiated, and n is the refractive index of the heating / cooling suppressing film 1.

The thickness of the heating / cooling suppressing film 1 formed on the a-Si film 2 is such that the cap region complete melting energy is larger than the bare region complete melting energy, for example, about 203 nm. To form. According to preliminary experiments, the cap region complete melting energy for completely melting the cap region a-Si film 3 covered with the heating / cooling suppressing film 1 having a thickness of about 203 nm by the XeCl laser is about 550 mJ / It was cm ² . Bare region a− that is not covered by the heating / cooling suppression film 1
According to preliminary experiments, the bare region complete melting energy for completely melting the Si film 4 by the XeCl laser is
It was about 440 mJ / cm ² .

FIG. 5 is a sectional view for explaining the step of irradiating the first laser beam. The first laser beam 7 having an energy density of greater 590mJ / cm ² than the cap region completely melted Energy 550 mJ / cm ² 308 nm
The a-Si film 2 is irradiated from the heating / cooling suppression film 1 side with a XeCl laser having a wavelength of. The beam size of the laser light 7 is 0.5 mm × 100 mm.
The Tion Retio is 80 Hz, and the stage feed speed is 40 mm / sec.

When the first laser beam 7 having an energy larger than the complete melting energy of the cap region is irradiated, the cap region a covered with the heating / cooling suppressing film 1 is formed.
The -Si film 3 and the bare region a-Si film 4 not covered with the heating / cooling suppression film 1 are completely melted.

FIG. 6 is a perspective view for explaining the cap region crystallization process, and FIG. 7 is a plan view thereof. Referring to FIGS. 5, 6 and 7, since the heating / cooling suppressing film 1 is composed of a silicon oxide film having a large heat capacity, the completely melted cap region a-Si film 3 is the cap region a-Si film. Cooling is suppressed by the heating / cooling suppressing film 1 that covers the cooling layer 3. Therefore, the bare region a-Si film 4 is solidified before the cap region a-Si film 3 whose cooling is suppressed by the heating / cooling suppressing film 1.

The crystal grains forming the cap region Si film 3 are based on the crystal nuclei present in the previously solidified bare region Si film 4, as shown in FIGS.
Crystals are grown and crystallized laterally from both sides of the film 3 toward the center.

FIG. 8 is a sectional view for explaining the step of irradiating the second laser beam. Bare region complete melting energy 44
0 mJ / large cap region than cm ² complete melting energy 550 mJ / cm less than ² 450 mJ / c
The ^second laser beam 8 having an energy density of m ²
The Si film 2 is irradiated from the heating / cooling suppression film 1 side with a XeCl laser having a wavelength of 08 nm. The beam size of the laser light 8 is the same as that of the first laser light 7 described above.
0.5mm x 100mm, Repetition
Retio is 80Hz and stage feed speed is 4
It is 0 mm / sec.

When the second laser beam 8 having an energy larger than the complete melting energy of the bare region and smaller than the complete melting energy of the cap region is irradiated, the heating and cooling suppressing film 1 suppresses the heating of the cap region Si film 3. Therefore, only the bare region Si film 4 is completely melted.

FIG. 9 is a perspective view for explaining the bare region crystallization process, and FIG. 10 is a plan view thereof. Referring to FIGS. 8, 9 and 10, the completely melted bare region Si film 4
Is based on the crystal nuclei existing in the cap region Si film 3 whose heating is suppressed by the heating / cooling suppression film 1, and as shown in FIGS. Crystals grow and crystallize in the direction.

Then, the heating / cooling suppressing film 1 is removed from the Si film 2 by etching using the BHF 110.

FIG. 11 is a plan view schematically showing the crystalline semiconductor film according to the first preferred embodiment. FIG. 11 shows the crystalline state of the crystalline silicon film 9 observed by SEM after removing the heating / cooling suppressing film 1. Cap area S
The crystal grains forming the i film 3 are the cap region Si film 3 in contact with the bare region Si film 4 adjacent to the cap region Si film 3.
Laterally grow from both ends toward the center of the cap region Si film 3. The crystal grains grown from both ends of the cap region Si film 3 toward the center collide with each other at the center of the cap region Si film 3, and the cap region S
At the center of the i film 3, a crystal grain boundary is formed along the longitudinal direction of the cap region Si film 3.

The crystal grains forming the bare region Si film 4 are horizontally oriented from both ends of the bare region Si film 4 in contact with the cap region Si film 3 adjacent to the bare region Si film 4 toward the center of the bare region Si film 4. Growing. Bare region Si film 4
Crystal grains grown from both ends toward the center collide with each other in the center of the bare region Si film 4 and form a grain boundary along the longitudinal direction of the bare region Si film 4 in the center of the bare region Si film 4. To do.

As described above, in the crystalline silicon film 9, the crystal grains grown in the lateral direction are formed without any gap.

Next, using the crystalline silicon film 9 thus formed, an n-channel thin film transistor having a channel arranged in the width direction and an n-channel thin film having a channel arranged in the crystal growth direction are used. A thin film transistor is manufactured. In the n-channel thin film transistor in which channels were arranged along the width direction, the mobility of carriers was 110 cm ² / Vs.

In the n-channel thin film transistor in which channels were arranged along the crystal growth direction, the carrier mobility was 300 cm ² / Vs. The defective rate defined by the variation of the threshold voltage is 0/100,
As a result of measuring the threshold voltage of 100 n-channel thin film transistors in which channels were arranged along the crystal growth direction, there was no defect.

As described above, in the method for forming a crystalline semiconductor film according to the first embodiment, the semiconductor film forming step of forming the a-Si film 2 on the glass substrate 5 and the striping of the semiconductor film at regular intervals. The cap region complete melting energy necessary for completely melting the plurality of heating / cooling suppressing films 1 arranged on the a-Si film 2 in a cap region a-Si film 3 covered by the heating / cooling suppressing film 1 is A heating / cooling suppression film forming step of forming a bare region a-Si film 4 not covered by the heating / cooling suppression film 1 with a film thickness larger than the bare region complete melting energy required for completely melting the bare region a-Si film 4. Cap region a-Si film 3 and bare region a-
A first irradiation step of irradiating the a-Si film 2 with a laser beam 7 having an energy larger than the cap region complete melting energy so that the Si film 4 is completely melted, and the complete melting. Cap region a-Si film 3
A crystallization process based on the bare region Si film 4 solidified prior to the cap region a-Si film 3 whose cooling is suppressed by the heating / cooling suppression film 1;
After the cap region crystallization process, the cap region Si film 3 is formed.
A laser beam 8 having an energy larger than the complete melting energy of the bare region and smaller than the complete melting energy of the cap region so that only the bare region Si film 4 is completely melted by suppressing the heating to the region by the heating / cooling suppressing film 1. Irradiation step of irradiating the Si film 2 from the heating / cooling prevention film 1 side, a bare region crystallization step of crystallizing the completely melted bare region Si film 4 based on the cap region Si film 3, and heating / cooling suppression The removal step of removing the film 1 from the Si film 2 is included.

Therefore, only the heating / cooling suppressing film 1 needs to be provided on the Si film 2, and the antireflection film 92 and the reflecting film 9 as in the prior art described above with reference to FIGS. 19 and 20.
3 and 3 need not be stacked on the a-Si film 2. Therefore, the process in the method for forming the crystalline semiconductor film can be simplified and the cost can be suppressed low.

Furthermore, after the first irradiation of laser light, 2
Before irradiating the second laser beam, in order to remove the reflection film 93 laminated on the antireflection film 92, the glass substrate 5 was taken out from the laser device, the reflection film 93 was removed, and the reflection film 93 was removed. It is not necessary to set the glass substrate 5 on the laser device again. Therefore, the process in the method for forming the crystalline semiconductor film can be further simplified, and the cost can be further reduced.

In the first embodiment described above,
An example in which the heating / cooling suppression film 1 is made of a silicon oxide film has been shown, but the present invention is not limited to this. The heating / cooling suppressing film 1 may be composed of any one of a silicon nitride film and a laminated film of a silicon oxide film and a silicon nitride film.

Next, another method for forming the crystalline semiconductor film according to the first embodiment will be described. The difference from the method for forming the crystalline semiconductor film described above with reference to FIGS. 1 to 11 is that the thickness of the heating / cooling suppressing film 1 is 101 nm, and the thickness of the heating / cooling suppressing film 1 is 101 nm. The point where the cap region complete melting energy is about 480 mJ / cm ² , and the energy density of the first laser beam 7 is larger than the cap region complete melting energy 480 mJ / cm ^2.
Since it is 10 mJ / cm ² and other points are the same as the above-described method for forming the crystalline semiconductor film, detailed description thereof will be omitted.

When the crystalline silicon film formed by such another method of forming a crystalline semiconductor film is observed by SEM, it is similar to the crystalline silicon film 9 formed by the above-described method of forming a crystalline semiconductor film. As shown in FIG. 11, the crystal grains forming the cap region Si film 3 are
The cap region Si film 3 is in contact with the adjacent bare region Si film 4 from both ends of the cap region Si film 3.
The film 3 was laterally grown toward the center of the film 3. The crystal grains grown from both ends of the cap region Si film 3 toward the center collide with each other in the center of the cap region Si film 3, and along the longitudinal direction of the cap region Si film 3 in the center of the cap region Si film 3. A grain boundary was formed.

The crystal grains forming the bare region Si film 4 are horizontally oriented from both ends of the bare region Si film 4 in contact with the adjacent cap region Si film 3 to the bare region Si film 4 toward the center of the bare region Si film 4. Was growing up. Bare region Si film 4
Crystal grains grown from both ends toward the center collide with each other in the center of the bare region Si film 4 and form a grain boundary along the longitudinal direction of the bare region Si film 4 in the center of the bare region Si film 4. Was.

As described above, in the crystalline silicon film, the crystal grains grown in the lateral direction were formed without any gap.

Next, using the crystalline silicon film according to another method of forming the crystalline semiconductor film thus formed, an n-channel thin film transistor having channels arranged in the width direction and a crystal growth direction An n-channel thin film transistor having a channel arranged along the above was manufactured. In an n-channel thin film transistor in which channels are arranged along the width direction, carrier mobility is 100 cm ²
Was / Vs.

In the n-channel thin film transistor in which channels were arranged along the crystal growth direction, the carrier mobility was 295 cm ² / Vs. The defective rate defined by the variation of the threshold voltage is 0/100,
As a result of measuring the threshold voltage of 100 n-channel thin film transistors in which channels were arranged along the crystal growth direction, there was no defect.

Next, a method of forming a crystalline semiconductor film according to a comparative example will be described. FIG. 12 is a plan view schematically showing a crystalline semiconductor film according to a comparative example. The difference from the method for forming a crystalline semiconductor film according to Embodiment 1 described above with reference to FIGS. 1 to 11 is that the thickness of the heating / cooling suppressing film 1 is set so that the cap region complete melting energy is more that was also a 53nm with a thickness such as to be smaller, and in that a cap region completely melted energy for this is the smaller of about 360 mJ / cm ² than the bare area completely melted energy 440 mJ / cm ^2. The energy density of the first laser beam 7 is higher than both the bare region complete melting energy 440 mJ / cm ² and the cap region complete melting energy 360 mJ / cm ² 450.
mJ / cm ² and the energy density of the second laser beam 8 is 360 mJ / c for the complete melting energy of the cap region.
Greater than m ² bare area complete melting energy 440 m
It was 400 mJ / cm ² , which was smaller than J / cm ² . Since the other points are the same as those of the crystalline semiconductor film forming method described above, detailed description thereof will be omitted.

A crystalline silicon film formed by the method for forming a crystalline semiconductor film according to the comparative example is subjected to SEM.
Observed by, as shown in FIG. 12, the crystal grains forming the cap region Si film 3 are
Is in contact with the bare region Si film 4 adjacent to the cap region Si
Lateral growth was performed from both ends of the film 3 toward the center of the cap region Si film 3.

However, in the bare region Si film 4, the crystal grain was a microcrystalline region in which lateral growth did not occur. The reason for this is as described below. Since the thickness 53 nm of the heating / cooling suppressing film 1 is thinner than the thicknesses 203 nm and 101 nm of the heating / cooling suppressing film 1 according to the first embodiment, the heating / cooling suppressing film 1 is capped after the first irradiation of the laser beam 7. It does not function as a cooling suppression film for the region a-Si film 3. Therefore, the bare region a-Si film 4 does not solidify before the cap region a-Si film 3, and the cap region a-Si film 4 does not solidify.
The -Si film 3 cannot laterally grow based on the previously solidified bare region Si film 4. In this state, when a second laser beam having an energy larger than the cap region complete melting energy and smaller than the bare region complete melting energy is irradiated, only the cap region Si film 3 is completely melted. The completely melted cap region Si film 3 is
Lateral growth is performed based on the bare region Si film 4. For this reason, as shown in FIG. 12, the crystal grains grow laterally only in the cap region Si film 3, and the bare region Si film 4 becomes a microcrystalline region in which the crystal grains do not grow laterally.
Areas in which crystal grains were laterally grown and microcrystalline areas were alternately formed.

Next, a method for forming a crystalline semiconductor film according to another comparative example will be described. 13 and 14 are cross-sectional views illustrating a method for forming a crystalline semiconductor film according to another comparative example. Referring to FIG. 13, first, the base coat film 6 made of a silicon oxide film is formed on the glass substrate 5 by P
-It is formed to a thickness of 300 nm by the CVD method. Then, the a-Si film 2 is formed on the base coat film 6 by P-CVD to have a thickness of 45 nm. Next, the glass substrate 5 on which the a-Si film 2 and the base coat film 6 are formed is heated at 500 ° C. for 1 hour in a nitrogen atmosphere in an electric furnace to dehydrogenate the a-Si film 2.

Referring to FIG. 14, a silicon oxide film 53n is then formed on the a-Si film 2 by P-CVD.
It is formed to a thickness of m. Then, an aluminum film having a thickness of 300 nm is deposited on the silicon oxide film by a sputtering method. Next, the aluminum film formed on the silicon oxide film is patterned by dry etching using BCl ₃ to form a reflection film 93. afterwards,
The antireflection film 92 is formed by patterning the silicon oxide film by etching using the BHF 110 using the patterned reflection film 93 as a mask. In this way, a laminated film of the antireflection film 92 and the reflection film 93 is formed on the a-Si film 2 in a stripe shape having a width of 2 microns with an interval of 2 microns.

Then, the first laser beam having an energy density of 450 mJ / cm ² was irradiated with the XeCl laser having a wavelength of 308 nm to form the antireflection film 92 and the reflection film 93.
The a-Si film 2 is irradiated from the side of the laminated film of. After that, the reflective film 93 is removed by etching with an SLA etchant using phosphoric acid and acetic acid. And 390m
The a-Si film 2 is irradiated with the second laser light having an energy density of J / cm ² from the antireflection film 92 side. Both the first laser light and the second laser light have a beam size of 0.5 mm × 100 mm.
on Retio is 80 Hz, and the stage feed rate is 40 mm / sec. Then, the antireflection film 92 is removed from the a-Si film 2 by etching using the BHF 110.

FIG. 15 is a plan view schematically showing a crystalline semiconductor film according to another comparative example. FIG. 15 shows the crystalline state of the crystalline silicon film observed by SEM after removing the antireflection film 92. Cap area Si film 3
The crystal grains constituting the crystal are laterally grown from both ends of the cap region Si film 3 toward the center. Bare area Si
Crystal grains forming the film 4 are laterally grown from both ends of the bare region Si film 4 toward the center. However, spot-like spots 94 are formed here and there. This is because when the first laser beam is irradiated, the reflection film 93 made of metal melts and flows down onto the bare region Si film 4, or the reflection film 93 evaporates and vaporizes to leave the bare region Si film 4. This is a result of the Si film 2 being contaminated because it adheres to the top.

Next, using the crystalline silicon film 9 thus formed, an n-channel thin film transistor having a channel arranged in the width direction and an n-channel thin film having a channel arranged in the crystal growth direction are used. A thin film transistor is manufactured. The mobility of carriers was 100 cm ² / Vs in an n-channel thin film transistor in which channels were arranged along the width direction. In the n-channel thin film transistor in which the channels were arranged along the crystal growth direction, the carrier mobility was 295 cm ² / Vs.

However, the variation of the threshold voltage is larger than the variation of the threshold voltage of the thin film transistor according to the first embodiment, and the defective rate defined by the variation of the threshold voltage is 13/100, which is along the crystal growth direction. As a result of measuring the threshold voltage of 100 n-channel thin film transistors with channels arranged, there were 13 defects.

(Embodiment 2) In Embodiment 2, a method of manufacturing a semiconductor device in which a crystalline semiconductor film formed by the method of forming a crystalline semiconductor film according to Embodiment 1 is used as a channel region will be described. To do. FIG. 16 is a plan view illustrating the method of manufacturing the thin film transistor in which the crystalline semiconductor film according to the second embodiment is used as the channel region. FIG. 17 is a plan view of a thin film transistor having a crystalline semiconductor film as a channel region.

First, as in the first embodiment, the base coat film is formed on the glass substrate. Then, an a-Si film is formed on the base coat film. Next, a-S
The glass substrate on which the i film and the base coat film are formed is heated in an electric furnace to dehydrogenate the a-Si film.

As shown in FIG. 16, the a-Si film has a substantially rectangular region 10 provided adjacent to each other.
And area 11. In the region 10, a plurality of heating / cooling suppressing films 1 are formed which are arranged in stripes at regular intervals along the left-right direction in FIG. In the region 11, a plurality of heating / cooling suppressing films 1 are arranged in stripes at regular intervals in the vertical direction in FIG. 16 which is perpendicular to the longitudinal direction of the heating / cooling suppressing film 1 formed in the region 10. Form.

Thus, the direction in which the heating / cooling suppressing film 1 formed in the region 10 extends is orthogonal to the direction in which the heating / cooling suppressing film 1 formed in the region 11 extends. Area 1
The direction in which the crystal grains of the cap region Si film and the bare region Si film at 0 grow is the vertical direction perpendicular to the horizontal direction in FIG. 16 in which the heating and cooling suppression film 1 formed in the region 10 extends. The direction in which the crystal grains of the cap region Si film and the bare region Si film grow in the region 11 is the horizontal direction perpendicular to the vertical direction in FIG. 16 in which the heating and cooling suppression film 1 formed in the region 11 extends. Therefore, the crystal grains in the region 11 grow along the direction perpendicular to the growing direction of the crystal grains in the region 11.

Therefore, as shown in FIG.
In the region 10, a TFT 12 having a source region 13 and a drain basin 14 is formed along the vertical direction in which the crystal grains grow in the region 10, and in the region 11, the source region 1 extends in the horizontal direction in which the crystal grains grow in the region 11.
When the TFT 12 provided with the drain region 3 and the drain region 14 is formed, the TF having the channel region with high carrier mobility is formed.
T can be formed. Therefore, high performance TF
T can be obtained.

[0090]

As described above, according to the present invention, it is possible to provide a method for forming a crystalline semiconductor film, a crystalline semiconductor film, a method for manufacturing a semiconductor device, and a semiconductor device which are simple in process.

Further, according to the present invention, it is possible to provide a method for forming a crystalline semiconductor film and a crystalline semiconductor film which are low in cost, a method for manufacturing a semiconductor device and a semiconductor device.

[Brief description of drawings]

FIG. 1 is a cross-sectional view illustrating a step of forming an amorphous silicon film in the method for forming a crystalline semiconductor film according to the first embodiment.

FIG. 2 is a cross-sectional view illustrating a step of forming a heating / cooling suppressing film in the method for forming a crystalline semiconductor film according to the first embodiment.

FIG. 3 is a perspective view illustrating a step of forming a heating / cooling suppressing film in the method for forming a crystalline semiconductor film according to the first embodiment.

FIG. 4 is a graph showing the relationship between the film thickness of the heating / cooling suppressing film and the cap region complete melting energy according to the first embodiment.

FIG. 5 is a cross-sectional view illustrating a step of irradiating a first laser beam in the method for forming a crystalline semiconductor film according to the first embodiment.

FIG. 6 is a perspective view illustrating a cap region crystallization step in the method for forming a crystalline semiconductor film according to the first embodiment.

FIG. 7 is a plan view illustrating a cap region crystallization step in the crystalline semiconductor film forming method according to the first embodiment.

FIG. 8 is a cross-sectional view illustrating a step of irradiating a second laser beam in the method for forming a crystalline semiconductor film according to the first embodiment.

FIG. 9 is a perspective view illustrating a bare region crystallization step in the method for forming a crystalline semiconductor film according to the first embodiment.

FIG. 10 is a plan view illustrating a bare region crystallization step in the method for forming a crystalline semiconductor film according to the first embodiment.

FIG. 11 is a plan view schematically showing the crystalline semiconductor film according to the first embodiment.

FIG. 12 is a plan view schematically showing a crystalline semiconductor film according to a comparative example in the first embodiment.

FIG. 13 is a cross-sectional view illustrating a method for forming a crystalline semiconductor film according to another comparative example in the first embodiment.

FIG. 14 is a cross-sectional view illustrating a method for forming a crystalline semiconductor film according to another comparative example in the first embodiment.

FIG. 15 is a plan view schematically showing a crystalline semiconductor film according to another comparative example in the first embodiment.

FIG. 16 is a plan view illustrating the method of manufacturing the thin film transistor in which the crystalline semiconductor film according to the second embodiment is formed as the channel region.

FIG. 17 is a plan view of a thin film transistor including a crystalline semiconductor film according to a second embodiment as a channel region.

18A is a cross-sectional view illustrating a conventional method for forming a crystalline semiconductor film, and FIG. 18B is a plan view thereof.

FIG. 19 is a cross-sectional view illustrating another conventional method for forming a crystalline semiconductor film.

FIG. 20 is a cross-sectional view illustrating another conventional method for forming a crystalline semiconductor film.

[Explanation of symbols]

1 Heating / cooling suppression film 2 Amorphous silicon film 3 Cap area amorphous silicon film 4 Bare region amorphous silicon film 5 glass substrates 6 Base coat film 7, 8 laser light 9 Polycrystalline silicon film

Claims (16)

[Claims] 1. A method for forming a crystalline semiconductor film by crystallizing a semiconductor film, the method comprising: forming a semiconductor film on an insulating substrate; and forming a predetermined film on the semiconductor film. A heating / cooling suppression film forming step of forming a plurality of thick heating / cooling suppression films in stripes at regular intervals, and a cap region semiconductor film covered by the heating / cooling suppression film and the heating / cooling suppression film. A first irradiation step of irradiating the semiconductor film with a first laser beam so that the bare region semiconductor film which is not melted is completely melted; and the completely melted cap region semiconductor film is bare region semiconductor A cap region crystallization step of crystallizing based on the film, and a second laser beam is suppressed in heating and cooling so that only the bare region semiconductor film is completely melted after the cap region crystallization step. A second irradiation step of irradiating the semiconductor film from the side, a bare region crystallization step of crystallizing the completely melted bare region semiconductor film based on the cap region semiconductor film, and a heating / cooling suppression film of the semiconductor film. A method for forming a crystalline semiconductor film, comprising a removing step of removing from above. 2. The predetermined thickness of each heating / cooling suppressing film is necessary for the cap region complete melting energy required for completely melting the cap region semiconductor film to completely melt the bare region semiconductor film. The film thickness is larger than the bare region complete melting energy, the first laser light has energy larger than the cap region complete melting energy, and the second laser light is the bare region complete melting energy. The method for forming a crystalline semiconductor film according to claim 1, wherein the crystalline semiconductor film has an energy larger than a melting energy and smaller than the cap region complete melting energy. 3. The first and the second laser lights each have a wavelength λ, and when the refractive index of the heating / cooling suppressing film is n, the thickness of the heating / cooling suppressing film is (3λ ) / (8n) or more, The method for forming a crystalline semiconductor film according to claim 1, wherein 4. The method for forming a crystalline semiconductor film according to claim 1, wherein the heating / cooling suppressing film is composed of a silicon oxide film. 5. The method for forming a crystalline semiconductor film according to claim 1, wherein the heating / cooling suppressing film is made of any one of a silicon nitride film, a silicon oxide film, and a laminated film of a silicon nitride film. 6. In the cap region semiconductor film crystallized in the cap region crystallization step, semiconductor crystal grains forming the cap region semiconductor film are in contact with a bare region semiconductor film adjacent to the cap region semiconductor film. The bare region semiconductor film, which is crystallized by lateral growth from both ends of the cap region semiconductor film toward the center of the cap region semiconductor film and crystallized in the bare region crystallization step, constitutes the bare region semiconductor film. The semiconductor crystal grains are crystallized by lateral growth of the bare region semiconductor film from both ends of the bare region semiconductor film in contact with the adjacent cap region semiconductor film toward the center of the bare region semiconductor film. Item 2. A method for forming a crystalline semiconductor film according to item 1. 7. A crystalline semiconductor film formed by the method for forming a crystalline semiconductor film according to claim 1. 8. A method of manufacturing a semiconductor device, comprising a crystalline semiconductor film obtained by crystallizing a semiconductor film as a channel region, comprising: a step of forming the semiconductor film on an insulating substrate; and a step of forming the semiconductor film. A heating / cooling suppression film forming step of forming a plurality of heating / cooling suppression films each of which has a predetermined film thickness and having a uniform thickness on each other in a stripe shape at regular intervals, and a cap region semiconductor film covered with the heating / cooling suppression film. And a first irradiation step of irradiating the semiconductor film with the first laser light from the heating / cooling suppression film side so that the bare region semiconductor film not covered with the heating / cooling suppression film is completely melted, and the completely melted cap A cap region crystallization process for crystallizing the region semiconductor film based on the bare region semiconductor film, and only the bare region semiconductor film is completely melted after the cap region crystallization process. Second irradiation step of irradiating the semiconductor film with the second laser light from the side of the heating / cooling suppressing film, and a bare region crystal for crystallizing the completely melted bare region semiconductor film based on the cap region semiconductor film A method of manufacturing a semiconductor device, comprising: a forming step; and a removing step of removing the heating / cooling suppressing film from the semiconductor film. 9. A method of manufacturing a semiconductor device, comprising a crystalline semiconductor film obtained by crystallizing a semiconductor film as a channel region, comprising: a step of forming the semiconductor film on an insulating substrate; and a step of forming the semiconductor film. A plurality of first heating / cooling suppressing films each having a predetermined film thickness equal to each other in the upper first region are formed in a stripe shape at regular intervals, and the first region is formed in the second region on the semiconductor film. A heating / cooling suppression film forming step of forming a plurality of second heating / cooling suppression films each having a predetermined film thickness along the direction intersecting with the heating / cooling suppression film in stripes at regular intervals; The first region is formed so that the cap region semiconductor film covered by the first and second heating / cooling suppressing films and the bare region semiconductor film not covered by any of the first and second heating / cooling suppressing films are completely melted. The laser light is applied to the first and the second
A first irradiation step of irradiating the semiconductor film from the heating / cooling suppression film side; a cap region crystallization step of crystallizing the completely melted cap region semiconductor film based on the bare region semiconductor film; After the step, a second laser beam is irradiated onto the semiconductor film from the first and second heating / cooling suppression film sides so that only the bare region semiconductor film is completely melted.
Irradiation step, bare area crystallization step of crystallizing the completely melted bare area semiconductor film based on the cap area semiconductor film, and removing the first and second heating / cooling suppression films from above the semiconductor film A method of manufacturing a semiconductor device, comprising: a removing step. 10. A semiconductor device manufactured by the method for manufacturing a semiconductor device according to claim 8. 11. A semiconductor device manufactured by the method for manufacturing a semiconductor device according to claim 9. 12. A semiconductor film, wherein a part of a crystal grain boundary of a laterally grown semiconductor crystal grain is in contact with an amorphous semiconductor film. 13. The laterally grown semiconductor crystal grains are in contact with each other at a crystal grain boundary, and the distance between adjacent crystal grain boundaries is
A semiconductor film characterized in that the distance is not more than twice the lateral growth distance of semiconductor crystal grains. 14. A crystalline semiconductor film in which semiconductor crystal grains are laterally grown along the surface of the amorphous insulating substrate is provided on the amorphous insulating substrate, and the crystalline semiconductor film is activated. A semiconductor device configured as a region, wherein the crystalline semiconductor film has a part of a crystal grain boundary of a laterally grown semiconductor crystal grain in contact with an amorphous semiconductor film. 15. A crystalline semiconductor film having semiconductor crystal grains laterally grown along the surface of the amorphous insulating substrate is provided on the amorphous insulating substrate, and the crystalline semiconductor film is activated. A semiconductor device configured as a region, wherein in the crystalline semiconductor film, laterally grown semiconductor crystal grains are in contact with each other at a crystal grain boundary, and the distance between adjacent crystal grain boundaries is such that the semiconductor crystal grains grow laterally. A semiconductor device characterized in that the distance is less than twice the distance. 16. The semiconductor device according to claim 14, wherein a plurality of regions are provided in which the directions of lateral growth of the semiconductor crystal grains are orthogonal to each other.
5. The semiconductor device according to item 5.