JPH08203822A - Thin film semiconductor material forming equipment - Google Patents

Abstract

(57) [Summary] [Object] To provide a thin film semiconductor material forming apparatus for irradiating a semiconductor substrate with a linear heat source having a periodic intensity distribution easily and accurately. A linear heat source or a semiconductor substrate having a polycrystalline or amorphous Si film formed thereon is relatively moved, comprising a member having at least two regions having different transmissivities with respect to radiation from the linear heat source. By radiating the radiation from the linear heat source through the member and irradiating the semiconductor substrate, the thin film semiconductor material partially free of crystal defects can be formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film semiconductor material forming apparatus, and more particularly to a thin film semiconductor material forming apparatus for forming single crystal Si on an insulating material.

[0002]

2. Description of the Related Art S for forming single crystal Si on an insulating material
Many techniques have been proposed for the OI (Silicon On Insulator) technique, but among them, polycrystalline or amorphous Si formed on an insulating material is melted and recrystallized to form a single crystal. The method is particularly effective as a basic technology for manufacturing a three-dimensional integrated circuit, and various methods using a strip heater, a laser beam, an electron beam, a halogen lamp, or the like as a heat source for melting and recrystallization are available. Being researched.

A single crystal Si thin film can be formed by growing a crystal from a single nucleus by the above-mentioned method.
In the single crystal Si produced by these methods, crystal defects called subgrain boundaries have an interval of 10 μm and a length of 100 μm.
It exists in a branch shape with m. FIG. 10 is a diagram showing how sub-grain boundaries are generated. The liquid phase 32 of Si is obtained by melting the polycrystalline Si 31 by the heat source irradiated from above the paper surface of FIG.
Are recrystallized to form the solid phase 33, the sub-grain boundaries 34
Is generated. In FIG. 10, the operation direction of the sample with respect to the heat source is the left direction, that is, the crystal growth direction is the right direction, and 35 is the solidification interface from the liquid phase 32 to the solid phase 33. This sub-grain boundary 34 is a slight crystal orientation deviation of 1 ° or less in the direction parallel to the film surface, and solidifies in the microscopic unevenness generated at the solidification interface 35 composed of facets during melt recrystallization. Is known to occur at a partially delayed position.

Generation of subgrain boundaries is unavoidable unless the solidification interface is completely flat at the atomic level. Further, a flat solidification interface is not achieved until the impurity concentration on the liquid phase side near the interface is extremely low, but in the case of the melt recrystallization method, a high temperature Si melt is surrounded by SiO _2. From the characteristic of the method of existence, it is unavoidable that oxygen as an impurity is dissolved in the Si melt according to the temperature gradient in the vicinity of the solidification interface, and therefore, the solidification interface has microscopic unevenness, Subgrain boundaries corresponding to it will always occur.

The existence of such sub-grain boundaries in single crystal Si causes variations in characteristics and the occurrence of defects when devices are formed therein. Therefore, as shown in FIG. 11, for example, a thin film semiconductor material, such as a polycrystalline Si film, is patterned into a connected island shape so as to be melted, and the heat flow in the connecting portion 37 of the connected island Si 36 is controlled. Method to suppress the generation of sub-grain boundaries (Fukami et al., IEICE Transactions, J69-C (1986) 1089)
Is proposed. However, according to this method, S
Since the i film is subdivided into a specific shape by patterning, the number of process steps for patterning is increased, the device layout is largely restricted, and there is a problem in that the substrate is effectively used. . On the other hand, in melt recrystallization of a continuous Si film, it is technically difficult to suppress the generation of subgrain boundaries. Therefore, a method of controlling the position where the sub-grain boundaries are generated to a position that does not affect the device characteristics has been proposed.

As a method for controlling the position of sub-grain boundary generation, the method shown in FIG.
As shown in FIG. 2, for example, a polycrystalline Si film 40 is formed on the thermally oxidized Si 39 formed by thermally oxidizing the surface of the Si wafer 38, and a surface protection layer 41 is further laminated on the thin film semiconductor material substrate. , There is a method of forming a periodic heat generating portion 42 in a stripe shape by various methods and scanning a heat source in a direction parallel to the heat generating portion 42 (J. Electr).
ochem. Soc, 130, p. 1178 (198
3)). According to this method, the polycrystalline Si film 40 is heated by the heat source.
The Si melt in which is melted has a high temperature under the heat generating portion 42 and delays solidification, so that the generation of sub-grain boundaries can be concentrated there. Further, band-shaped pattern regions having different laser light reflectances are periodically formed on the substrate to achieve the same effect, and melt recrystallization in which the position of generation of sub-grain boundaries is controlled is performed (Japanese Patent Laid-Open No. Sho 61-96). 62-179112).

In the above-described method, the stripe-shaped heat generating portion and the band-shaped pattern area having different reflectance of laser light are periodically formed, so that the upper portion of the Si film has a periodic structure, and the melted film is melted again. It is known that a phenomenon (bead-up phenomenon) occurs in which the Si melt locally pops and rounds during crystallization. For example, in the example shown in FIG. 12, the surface protection layer 41 interposed between the Si film 40 and the heat generating portion 42 is formed to prevent impurities from being mixed and to suppress such a bead-up phenomenon. However, as an effect of periodically forming the heat generating portion and the like, the strength of the surface protective layer also becomes periodic. Therefore, while there is an effect of suppressing bead up,
As shown in FIG. 3, the single-crystallized Si film 43 is periodically deformed and its flatness is lowered, and a further flattening process is required to form a device having a multilayer structure. There is. Further, according to the above-mentioned method, there is a problem that a step for forming a heat generating part or the like on each thin film semiconductor material substrate is required, which complicates the process and lengthens the time.

When performing a melt recrystallization, if a periodic structure of heat is formed in a direction parallel to the direction promoting the recrystallization, S
The i-melt is periodically heated to a high temperature, and sub-grain boundaries are concentrated at positions where solidification is partially delayed. As a method of forming such a periodic structure of heat, a method of forming a specific periodic structure on the substrate side and making the heat source itself linear with periodic intensity can be considered. If this is possible, it is possible to avoid the deformation of the recrystallized Si film due to the periodical change in the strength of the surface protective layer without adding a substrate processing process.

As one method of linearizing the heat source itself with a periodic intensity, as shown in FIG. 14, a plurality of laser beams having a Gaussian intensity distribution are overlapped at appropriate intervals. However, a method of arranging them in a straight line has been proposed (Japanese Patent Laid-Open No. 59-52831). In FIG. 14 (a), a circle 44 indicates the range over which the intensity of each laser beam extends. Each circle corresponds to each laser beam, the maximum intensity is at the center of the circle, and the intensity reaches the contour of the circle. It means that it extends. Further, FIG. 14B shows the overall laser intensity distribution obtained by combining the laser beams shown in FIG. 14A. In this case, since the high temperature part in the thermal periodic structure corresponds to the maximum intensity position of each laser beam forming the linear laser, the number of laser beams required to generate sub-grain boundaries is required. Usually, the intervals at which sub-grain boundaries are generated are several tens of μm, and the cycle of the heat periodic structure for controlling the position is at most about 100 μm. Therefore, in order to recrystallize a wide area of several tens mm or several hundred mm at the same time in order to increase the throughput, an extremely large number of laser beams are required. At this time, it is not appropriate to use a plurality of laser light sources because the device becomes large and the cost is increased.

Therefore, a method of dividing laser light from a single laser light source by using some kind of optical member can be considered. As one of such methods, as shown in FIG. 15A, a laser beam 45 having a Gaussian intensity distribution is passed through a plurality of sub refraction plates 46 and 48 to form a multimodal intensity distribution. A method has been proposed. (JP-A-59-
121822). Reference numeral 47 is a (γ / 4) plate for adjusting the wavelength. By using such a method, a laser having a desired intensity distribution can be obtained as shown in FIG. However, when this method is used, the number of laser beams doubles each time it passes through the sub refraction plate, but when recrystallizing a wide region at the same time, the number of sub refraction plates is also reduced. It requires a very large number, which makes the optical component complicated and expensive,
Further, the absorption of laser light in the sub refraction plate cannot be ignored.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the above-mentioned conventional techniques, and provides a semiconductor substrate having a polycrystalline or amorphous Si film formed on an insulating material. It is arranged at a position facing a linear heat source with a substantially uniform intensity distribution in the length direction, and the linear heat source or the semiconductor substrate is relatively moved so that the radiation from the linear heat source irradiates the semiconductor substrate evenly. Polycrystalline or amorphous Si
When the film is melted and recrystallized into a single-crystal Si film, the solidification interface of Si is periodically delayed in the direction parallel to the moving direction of the heat source or the semiconductor substrate to concentrate the sub-grain boundaries and partially In a thin film semiconductor material forming apparatus that uses a method of forming a region without subgrain boundaries (hereinafter referred to as an entrainment method), the thin film semiconductor material substrate is not processed to have a periodic heat structure, It is an object of the present invention to provide a thin film semiconductor material forming apparatus that easily and accurately forms a linear heat source having properties and irradiates the thin film semiconductor material substrate.

[0012]

In order to achieve the above-mentioned object, a thin film semiconductor material forming apparatus of the present invention has a length of a semiconductor substrate having a polycrystalline or amorphous Si film formed on an insulating material. The linear heat source or the semiconductor substrate is relatively moved so that the radiation from the linear heat source uniformly irradiates the semiconductor substrate. A thin film semiconductor material forming apparatus for melting and recrystallizing a crystalline or amorphous Si film into a single crystal Si film, comprising a member having at least two regions having different transmissivities with respect to radiation from a linear heat source, The main feature is that the semiconductor substrate is irradiated with the radiation from the heat source after passing through the member.

[0013]

When the thin film semiconductor material forming apparatus of the present invention is used,
It is possible to easily and accurately form a linear heat source having a periodicity in the intensity distribution. When melting or recrystallizing polycrystalline or amorphous Si into single crystal Si, the solidification interface of Si is used as a semiconductor substrate or It is possible to delay in a direction parallel to the moving direction of the linear heat source and concentrate the sub-grain boundaries there to form a region without sub-grain boundaries.

[0014]

EXAMPLES The present invention will now be described in more detail with reference to examples. (Embodiment 1) In Embodiment 1 of the present invention, in a thin film semiconductor material forming apparatus using an entrainment method, a linear heat source having a substantially uniform strength distribution in the longitudinal direction is provided in the longitudinal direction of the linear heat source. By using a member that periodically changes the intensity, the intensity distribution of the linear heat source is changed at a period of about 100 μm or less to irradiate the semiconductor substrate.

FIG. 1 shows a schematic configuration of a semiconductor material forming apparatus according to a first embodiment of the present invention. In FIG. 1A, 1 is output 1.
It is an Ar laser light source with 0 W and a beam diameter of 1.5 mm.
The Ar laser light 6 emitted from here is passed through the lens 2 so that the beam diameter is condensed to 50 μm at the position of the sample 5. The laser light passing through the lens is then turned back toward the sample by the mirror 3 for beam scanning. By driving this mirror as shown by 7, the laser beam 6 linearly reciprocally scans a range of 10 mm width on the sample at a scanning speed of 10 cm / sec. FIG. 1B is the same as FIG.
FIG. 7A shows a cross-sectional view taken along a line Y, which is orthogonal to the traveling direction of the laser light 6 indicated by XX ′ in FIG. 8A, and the laser light 6 has a uniform intensity in the length direction as indicated by 8. It becomes a linear heat source. In the present embodiment, laser beam scanning with Ar laser light is given as an example of irradiation with a linear heat source, but the linear heat source may be generated from other sources such as an electron beam that can be used as a heat source. It may be.

The pseudo linear beam 8 obtained by folding back the beam scanning mirror 3 then passes through the beam transforming substrate 4 placed at a position of about 5 mm above the sample. This beam deformation substrate has a thickness of 0.5 mm as shown in FIG.
The Cr pattern 10 is patterned in stripes on the glass substrate 9 with a width of 20 μm and an interval of 80 μm. By injecting the pseudo linear beam 8 from the direction orthogonal to the surface on which the stripe is formed, the beam transmitted through the glass substrate 9 is irradiated on the sample 5 at a cycle of about 100 μm. Regarding the cycle of the intensity change of the linear heat source 8 at this time, it may be set so that the generation position thereof is effectively controlled in accordance with the interval of the generated sub-grain boundaries, but the generation of the sub-grain boundaries occurs. The interval is usually several tens of μm, and the cycle of the thermal periodic structure for controlling the position is at most 10
Since it is about 0 μm, it is preferably about 100 μm or less.

The above-mentioned mirror 3 is driven so as to obtain the pseudo linear beam 8. Therefore, if it is such a structure, the optical system may have another structure. For example, as shown in FIG. 3, a plurality (two in this example) of mirrors 3 and 11 may be used in combination. In this case, if at least one mirror is driven in the same manner as described above, a pseudo linear shape is obtained. Beam 8 can be obtained.

Next, the result of actual recrystallization using the above-mentioned apparatus will be described below. An example of the sample to be recrystallized is shown in FIG. In FIG. 4, a Si thermal oxide film 13 having a thickness of 1 μm is formed on the Si wafer 12, and C is formed thereon.
The polycrystalline Si film 14 is formed by 3000 V by the VD method, and the SiO ₂ film 15 is formed by the CVD method as a surface protection layer by 1.5 μm.

When the sample having such a layer structure is irradiated with the pseudo linear beam 8 and the sample is scanned at 1 mm / sec in the direction orthogonal to the pseudo linear beam 8, the beam is directly irradiated by being reflected by the Cr pattern 10. Even if it is not done, about 1
The polycrystalline Si film 14 is melted due to the temperature rise in the melting region due to the beam irradiation formed in the cycle of 00 μm, and as a result, the continuous S having a periodic change in spread as shown in FIG.
A fused region 16 of i was formed. That is, it was possible to obtain the same effect as that using the heat source shown in FIG. 14 in which the laser light was formed on a plurality of straight lines. In FIG. 5, 17 is a sub-grain boundary and 18 is a Si recrystallized film. In the above-described embodiment, the semiconductor substrate to be melted and recrystallized is moved with respect to the fixed linear heat source, but the linear heat source is irradiated so that the radiation from the linear heat source evenly irradiates the semiconductor substrate. Alternatively, the semiconductor substrate may be moved relatively, for example, the linear heat source may be moved with respect to the fixed semiconductor substrate. Further, in the above-mentioned embodiment, the linear heat source is formed as a linear heat source, but it may be formed in a curved line or a polygonal line shape without departing from the spirit of the present invention. However, the linear heat source is effective because it can easily generate sub-grain boundaries at desired positions in a concentrated manner.
Further, the laser light output of 10 W is set in consideration of the fact that Si in the sample can be completely and continuously melted at the beam reciprocating scanning speed and the sample scanning speed described above. Therefore, if Si can be melted completely continuously, the output as a heat source may have another value. Further, although the Cr pattern 10 is formed in a stripe shape on the glass substrate 9, as long as it can prevent the transmission of the laser light or weaken or reflect the laser light within the range not departing from the gist of the present invention, other It may be formed by using the above material, or may be formed in another shape.

When the single crystal Si formed by the above-described method was evaluated, it was found that when recrystallization was performed, the solidification interface was scanned by the substrate at the position where the periodically formed beam was directly irradiated and the melting region expanded. On the other hand, the generation of the sub-grain boundaries 17 concentrates at this position where the recrystallization is delayed periodically, and about 1 mm is generated in the Si recrystallization film 18 having a width of about 10 mm.
There are 10 subgrain-free regions with a width of about 80 μm in a cycle of 00 μm.
It was found that the film was formed with a flatness of 0 Å or less.

(Embodiment 2) In Embodiment 2, the linear heat source with uniform intensity distribution in the length direction of Embodiment 1 relating to the thin film semiconductor material forming apparatus using the entrainment method is used.
It is formed by arranging a plurality of single laser beams parallel to each other and adjacent to each other on the semiconductor substrate such that the ranges of their intensities overlap.

FIG. 6 shows a schematic configuration of the semiconductor material forming apparatus of the second embodiment. In FIG. 6A, 19 is an output 20.
W is an Ar laser light source with a beam diameter of 1.5 mm, and five identical laser light sources are installed side by side. The laser beam emitted from each Ar laser light source 19 was passed through a laser beam expander 20 having a conversion rate of 10 times immediately after the emission, so that the beam diameter was set to 15 mm. These 5
A beam combining optical system 22 including a mirror and a polarization beam splitter superimposes the beam 21 of each of the beams by the radius of the beam as shown by 23, and when viewed as a whole, the beam 21 has a substantially linear shape as shown in FIG. 6B. And a linear beam having a uniform intensity over a width of about 30 mm was formed. It should be noted that the circle representing each laser beam of the beam arrangement shown by 23 has the maximum intensity at the center portion of the circle, and the laser beam intensity extends to the contour portion of the circle. Therefore, as a result of combining the intensities of the respective laser lights, the intensity distribution as a whole as shown in FIG. 6B is obtained.

The sample was scanned at 0.5 mm / sec while irradiating the sample with the uniform linear beam thus formed through the beam-deforming substrate in the same manner as in Example 1. A controlled recrystallized film with equivalent sub-grain position could be obtained over a width of about 30 mm.

(Embodiment 3) In Embodiment 3, the linear heat source having a uniform intensity distribution in the length direction of Embodiment 1 relating to the thin film semiconductor material forming apparatus using the entrainment method is used.
Formed by stacking multiple parallel laser beams,
Further, an optical member that forms a stripe-shaped antireflection film for laser light and periodically changes the intensity of the linear heat source in the lengthwise direction is used as the beam deforming substrate.

7A and 7B are schematic configuration diagrams of an optical member used in Example 3 for periodically changing the beam intensity in the lengthwise direction. FIG. 7A is a front view thereof, and FIG. It is the side view. In FIGS. 7A and 7B, 9
Is a glass substrate with a thickness of 0.5 mm similar to that used in Example 1, and a Si nitride film 24 formed on the glass substrate with a thickness such that the reflectance of Ar laser is minimized is
Stripes are patterned at 0 μm and at intervals of 80 μm.

Laser light from five 15 W Ar lasers was shaped into such an optical member into a uniform linear beam in the same manner as in Example 2, and then the striped antireflection film 24 shown in FIG. 7 was formed. When the sample is irradiated while being scanned through the beam-deforming optical member, the intensity of the laser beam that has passed through the antireflection film 24 is stronger, so that the molten region at the position irradiated with the laser beam periodically expands. .

At the position where the beam is irradiated through the antireflection film and the melting region spreads, the solidification interface is delayed with respect to the substrate scanning and the recrystallization is periodically delayed. Generation of sub-grain boundaries is concentrated, and in the recrystallized film having a width of about 30 mm, the width is about 8 μm at a cycle of about 100 μm.
A region having no grain boundary of 0 μm was formed with a flatness of 100 Å or less.

(Embodiment 4) In Embodiment 4, the linear heat source having a uniform strength distribution in the length direction of Embodiment 1 relating to the thin film semiconductor material forming apparatus using the entrainment method is used.
Formed by stacking multiple parallel laser beams,
Further, an optical member that periodically changes the intensity of the linear heat source in the lengthwise direction of the linear heat source is used as the beam deforming substrate as the striped laser light absorbing layer.

FIG. 8 is a schematic view of the structure of an optical member used in Example 4 for periodically changing the beam intensity in the longitudinal direction. FIG. 8 (a) is a front view thereof, and FIG. 8 (b) is a schematic view thereof. It is the side view. In FIGS. 8A and 8B, 9
Is a glass substrate with a thickness of 0.5 mm similar to that used in Example 1, and has a thickness of 1 on which an Ar laser is absorbed.
A Si film 25 having a thickness of 20 μm is patterned in a stripe shape with a width of 20 μm and an interval of 80 μm.

Laser light from five 20 W Ar lasers was shaped into such an optical member into a uniform linear beam in the same manner as in Example 2, and then the striped laser light absorption layer 25 shown in FIG. 8 was formed. When the sample is irradiated while being scanned through the beam-deforming optical member, the intensity of the laser light that has not passed through the laser light absorption layer 25 is higher, so that the melting region at the position irradiated with the laser light is stronger. Spread periodically.

At the position where the periodically formed molten region spreads, the solidification interface is delayed with respect to the substrate scanning, and the generation of sub-grain boundaries is concentrated at this position where the recrystallization is periodically delayed.
About 100 in a recrystallized film over a width of about 30 mm
100 Å in a region without sub-grain boundaries with a width of about 80 μm in a μm cycle
It was formed with the following flatness.

(Fifth Embodiment) In the fifth embodiment, a linear heat source having a uniform beam intensity distribution in the length direction of the thin film semiconductor material forming apparatus using the entrainment method is used in the length direction. An optical member that changes its intensity periodically has a means for cooling the member.

FIG. 9 shows a schematic configuration of the semiconductor material forming apparatus of the fifth embodiment. In FIG. 9, reference numeral 26 denotes an optical member similar to that used in the fourth embodiment, which periodically changes the beam intensity in the lengthwise direction. What is used in the fourth embodiment is Si.
The film thickness is different and about 1000Å. In addition, the optical member 26
A nozzle 27 that blows N ₂ gas to cool this is installed above. The reason why N ₂ gas is used in the cooling means is that this gas has no adverse effect on the formation of the thin film semiconductor material according to the present invention and there is no problem in terms of safety.

Laser light from five 17 W Ar lasers 19 is shaped into such an optical member 26 into a uniform linear beam by the laser beam expander 20 and the beam combining optical system 22 as in the second embodiment. When the sample 28 is irradiated while scanning it through the beam-deforming optical member 26 having the stripe-shaped laser light absorption layer formed thereon,
Since the intensity of the laser light that has not passed through the laser light absorption layer of the optical member 26 is stronger, the molten region at the position irradiated with the laser light periodically expands.

At the position where the periodically formed molten region spreads, the solidification interface is delayed with respect to the substrate scanning, and the generation of sub-grain boundaries is concentrated at this position where the recrystallization is periodically delayed.
About 100 in a recrystallized film over a width of about 30 mm
100 Å in a region without sub-grain boundaries with a width of about 80 μm in a μm cycle
It was formed with the following flatness.

(Embodiment 6) In Embodiment 6, a linear heat source having a uniform beam intensity distribution in the length direction of Embodiment 1 relating to the thin film semiconductor material forming apparatus using the entrainment method is arranged in the length direction. A member for periodically changing the strength and a semiconductor substrate are installed in parallel, and the distance between the member and the semiconductor substrate is about 1 mm or less.

The apparatus according to the sixth embodiment uses the same laser irradiation system and sample as in the first embodiment. Then, the substrate for beam deformation and the sample for beam deformation were placed in parallel with the distance changed from 1 mm to 5 mm at an interval of 1 mm, and the sample was melted and recrystallized by the same method as in Example 1. It was As a result, in any case, the sub-grain boundaries were periodically controlled to the position where recrystallization was delayed,
The morphology of subgrain boundaries at that time was different. That is, when the distance between the beam-deforming substrate and the sample is set to 2 mm or more, the position-controlled sub-grain boundaries do not become linear and are irregularly present in a region of a width of 10 to 20 μm at a cycle of about 100 μm. The region where no field exists does not have width 90-
Only 80 μm could be taken. On the other hand, when the distance between the beam deformation substrate and the sample is set to 1 mm, the sub-grain boundaries become a single linear shape, and the crystallinity is wide and good in the region other than the linear sub-grain boundaries at intervals of about 100 μm. It was possible to obtain a good single crystal Si.

(Embodiment 7) Embodiment 7 relates to a thin film semiconductor material forming apparatus using an entrainment method.
Nos. 6 to 6 are performed under a reduced pressure atmosphere.

When the melt recrystallization of each of Examples 1 to 6 was carried out under a reduced pressure atmosphere of 1 Torr or less, a recrystallized film having a more stable subgrain boundary generation position was formed at 20 to 30.
% Laser light output could be obtained. This is considered to be because heat fluctuation and loss due to convection were small due to the melt recrystallization under a reduced pressure atmosphere. According to this method, heat can be stably supplied and low output is obtained. Even if it is a heat source, there is an advantage that the generation position of the sub-grain boundaries can be controlled more stably.

[0040]

According to the present invention, the semiconductor substrate is provided with a member having at least two regions having different transmissivities with respect to the radiation from the linear heat source, and the radiation from the linear heat source is transmitted through the member. Since the irradiation is performed on the thin film semiconductor material substrate, the step of forming the periodic heat absorbing portions in a stripe shape on the thin film semiconductor material substrate is unnecessary, and the process can be prevented from becoming complicated and taking a long time. Further, since the periodic structure does not exist on the Si film, the strength of the cap layer has no periodicity, and the Si film is not deformed periodically to reduce the flatness. Therefore, a device having a multilayer structure is formed. Does not require a planarization step. Further, the substrate 1 in which an optical system for periodically changing the beam intensity is also patterned
It is as simple as one sheet and can avoid complication of the device.

Further, according to the present invention, as the linear heat source, a plurality of single laser lights are arranged in parallel with each other so that adjacent single laser lights have overlapping ranges on the semiconductor substrate. Since the one formed by arranging was used, in the method of high-speed scanning with a single laser light, when the laser light scanning distance for forming the linear heat source becomes long, the Si film is formed from the relationship between the laser output and the scanning speed. While it is difficult to obtain the energy density of the beam enough to melt it, it is possible to recrystallize any area at the same time by increasing the number of laser light sources, so it is easy to support large area substrates. Can improve the throughput.

Further, according to the present invention, since the member on which the antireflection film for the laser light is formed is used, the loss of the laser light due to the reflection from the member is reduced and the laser light can be effectively used. Laser power can be reduced.

Further, according to the present invention, since the member on which the laser light absorption layer is formed is used, a mechanism for receiving the reflected laser light is not required, and the device can be simplified.

Further, according to the present invention, since the cooling mechanism for cooling the beam deforming member is provided, even if the laser light absorbing layer is made thin, it does not melt due to absorption and heat generation of the laser light, and it is thin. A laser light absorption layer can be used.
In addition, since the sample is also irradiated with the light that is not absorbed by the laser light absorption layer, the laser output required for the melting and recrystallization can be made smaller than when the laser light absorption layer absorbs almost all the laser light.

Furthermore, according to the present invention, the semiconductor substrate and the beam-deforming member are substantially parallel to each other and the distance between them is about 1 mm.
Since the spread of the radiation of the heat source after passing through the member is small, the difference between the expanded and non-expanded portions of the periodically formed melting region is large, and the difference in the unevenness of the solidification interface of Si is The position of the sub-grain boundary can be controlled stably with a large size. When the sub-grain boundaries have a stable linear shape, the entire recrystallized region can be effectively used, which is convenient for device design.

[Brief description of drawings]

FIG. 1 is a semiconductor material forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a beam deforming substrate according to the first embodiment.

FIG. 3 is another configuration example of the optical system of the apparatus according to the first embodiment.

FIG. 4 is an example of a sample used in the present invention.

FIG. 5 is a diagram showing how Si is recrystallized by the semiconductor material forming apparatus of the first embodiment.

FIG. 6 is a semiconductor material forming apparatus according to a second embodiment of the present invention.

FIG. 7 is an optical member (beam deformation substrate) according to the third embodiment.
Is.

FIG. 8 is an optical member (beam deformation substrate) according to the fourth embodiment.
Is.

FIG. 9 is a semiconductor material forming apparatus according to a fifth embodiment of the present invention.

FIG. 10 is a diagram showing how subgrain boundaries are generated.

FIG. 11 is an example of a conventional technique for suppressing generation of sub-grain boundaries by forming a heat generating portion on a semiconductor substrate.

FIG. 12 is an example of a conventional technique in which a sub-grain boundary generation position is controlled by forming a heat generating portion on a semiconductor substrate.

FIG. 13 is a diagram showing a drawback of the conventional technique for controlling the position of sub-grain boundary generation.

FIG. 14 is an example of a conventional technique in which a heat source is linearly formed with periodic intensity.

FIG. 15 is an example of a conventional technique of dividing a laser beam from a single laser light source into a plurality of laser beams.

[Explanation of symbols]

1, 19 Ar Laser Light Source 2 Lens 3, 11 Mirror 4, 26 Beam Deformation Substrate 5, 28 Sample 6 Ar Laser Light 7 Mirror Driving Direction 8 Pseudo Linear Beam (Linear Heat Source) 9 Glass Substrate 10 Cr Pattern 12 Si Wafer 13 Si thermal oxide film 14 Polycrystalline Si film 15 SiO ₂ film 16 Si melting region 17 Sub-grain boundary 18 Si recrystallized film 20 Laser beam expander 21 Beam (laser light) 22 Beam combining optical system 23 Beam arrangement 24 Reflection Prevention film 25 Laser light absorption layer 27 Nozzle

Claims (8)

[Claims] 1. Polycrystalline or amorphous Si on an insulating material
The semiconductor substrate on which the film is formed is arranged at a position facing a linear heat source having a substantially uniform intensity distribution in the length direction, and the linear heat source uniformly irradiates the semiconductor substrate with radiation. By moving the heat source or the semiconductor substrate relatively, the polycrystalline or amorphous Si film is made into a single crystal Si.
In a thin film semiconductor material forming apparatus for melting and recrystallizing a film, a member having at least two regions having different transmissivities with respect to radiation from the linear heat source is provided, and the radiation from the linear heat source is provided with the member. An apparatus for forming a thin film semiconductor material, characterized by irradiating the semiconductor substrate after the light is transmitted. 2. The member is characterized in that two regions having different transmissivities with respect to radiation from the linear heat source are alternately arranged in stripes at a cycle of about 100 μm or less. The thin film semiconductor material forming apparatus according to claim 1. 3. The thin-film semiconductor material forming apparatus according to claim 1, wherein the linear heat source is a linear light source, and the radiation is light radiation. 4. The linear light source is arranged such that a plurality of single laser beams are parallel to each other and adjacent to each other so that the respective ranges of intensity of the single laser beams overlap on the semiconductor substrate. The thin film semiconductor material forming apparatus according to claim 3, wherein 5. The thin-film semiconductor material forming apparatus according to claim 4, wherein the member has an antireflection film for laser light formed in a stripe shape. 6. The thin film semiconductor material forming apparatus according to claim 4, wherein the member has a laser light absorption layer formed in a stripe shape. 7. The thin film semiconductor material forming apparatus according to claim 6, further comprising cooling means for cooling the member. 8. The thin-film semiconductor material forming apparatus according to claim 1, wherein the semiconductor substrate and the member are substantially parallel to each other and the distance between them is about 1 mm or less.