JPH0629212A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To obtain a substantial single-crystal silicon thin film by crystallizing an a-Si (amorphous silicon) thin film or a polycrystalline Si thin film on a substrate by a simple method. CONSTITUTION:A laser irradiation operation in order to form a nucleus and an annealing operation in order to grow the nucleus are performed simultaneously. That is to say, a crystallization apparatus wherein an excimer laser irradiation operation (hnu1) is performed from the surface side of a wafer 6 and a lamp annealing operation (hnu2) is performed from the rear side is used, and an a-Si thin film 21 is crystallized on a transparent quartz (SiO2) substrate 20. Then, the formation of crystal nuclei 22 and the growth of the nuclei in the two-dimensional direction progress in parallel, and substantial single-crystal Si thin films 23 are obtained. When an Si ion-beam annealing operation is performed in advance to parts other than the nucleus formation positions, it is possible to restrain that a regular grain boundary is formed. When an excimer laser is irradiated via a photomask, parts where the crystal nuclei 22 are produced can be specified easily.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and in particular, a single crystal silicon thin film for forming a channel region of a thin film transistor is formed by a simple method.
The present invention relates to a method for manufacturing a semiconductor device that can be used for mass production of three-dimensional devices by OI technology.

[0002]

2. Description of the Related Art Melt recrystallization by laser irradiation has been studied for the purpose of improving the crystallinity of polycrystalline silicon on an insulating film or growing a single crystal. In particular, the technology for growing a single crystal silicon thin film on a SiO ₂ substrate that has excellent interface characteristics with silicon is called SOI (Silicon-On-Insulator), and is a low-cost LSI process that is highly compatible with conventional semiconductor processes. Has the potential to be manufactured. In addition, it is highly anticipated as a technology that can realize a three-dimensional device by stacking multiple active layers with an insulating film interposed therebetween.

[0003] In addition to LSI, high-voltage devices and thin film transistors (TFTs) are used as application fields of SOI technology.
Etc. are considered. Among them, the TFT is used, for example, for constructing a matrix drive circuit of a liquid crystal display device. As a conventional TFT, a TFT in which a source / drain region and a channel region are formed in an amorphous silicon thin film or a polycrystalline silicon thin film is generally used. But,
For TFTs formed using these thin films as a base,
(A) Leakage current is large and there is a limit to high reliability of operation and reduction of power consumption, (b) Low carrier mobility and limit to high speed operation, (c) Design
The channel length is approaching the crystal grain size due to the miniaturization of rules, and especially when using a polycrystalline silicon thin film, the TFT
That the device characteristics of are likely to vary,
There is a problem such as.

Therefore, in order to further increase the speed and reliability of the TFT in the future, it is necessary to use a structurally uniform single crystal silicon thin film having no crystal grain boundary as a base.

[0005]

However, in such a conventional method, it is necessary to perform nucleation and nucleation in different steps using different devices, and it is desired to greatly improve productivity and economic efficiency. It is not possible. This makes the manufacturing process extremely complicated when, for example, manufacturing a three-dimensional device using TFTs by laminating several single-crystal silicon thin films with an interlayer insulating film interposed therebetween. Is also an obstacle.

Therefore, the present invention makes it possible to form a single crystal thin film with a simple device and process, greatly improve productivity and economic efficiency, and mass-produce semiconductor devices having a complicated three-dimensional structure. The purpose is to provide a possible method.

[0007]

A method of manufacturing a semiconductor device of the present invention is proposed to achieve the above-mentioned object, and an amorphous thin film or a polycrystalline thin film formed on a substrate is formed into a single crystal. It is characterized in that the nucleation by laser irradiation and the nuclei growth by the annealing treatment are performed at the same time when the single crystal thin film is formed by crystallization.

The present invention also provides a laser irradiation for nucleation and an annealing treatment for nucleation when an amorphous thin film or a polycrystalline thin film formed on a light transmissive substrate is monocrystallized. Is simultaneously applied to the substrate from the directions in which they are in a front-back relationship with each other.

According to the present invention, when an amorphous thin film or a polycrystalline thin film formed on a light transmissive substrate is monocrystallized to form a single crystal thin film, laser irradiation and lamp annealing are both performed on the substrate. Characterized by applying from the same side to the main surface of

The present invention is also characterized in that the light transmissive substrate is made of a silicon oxide material or a silicon nitride material, and the amorphous thin film or polycrystalline thin film is made of a silicon material.

According to the present invention, when an amorphous thin film or a polycrystalline thin film formed on a light-shielding substrate is monocrystallized to form a single crystal thin film, both laser irradiation and lamp annealing are performed on the substrate. It is characterized in that it is applied from the side where the amorphous thin film or the polycrystalline thin film is formed.

According to the present invention, the light-shielding substrate is composed of a silicon-based material having a surface coated with an insulating material,
The amorphous thin film or the polycrystalline thin film is made of a silicon material.

The present invention is also characterized in that prior to the nucleation, any position on the amorphous thin film or the polycrystalline thin film is thoroughly amorphized by ion implantation.

The present invention is further characterized in that the laser irradiation is performed through a photomask to selectively form nuclei at an arbitrary position on the amorphous thin film or the polycrystalline thin film.

[0015]

The present invention is characterized in that laser irradiation for nucleation and annealing treatment for nuclei growth are performed at the same time by using an apparatus having both a laser irradiation mechanism and an annealing treatment mechanism. The annealing process in this case is
Lamp annealing or resistance heating may be used. In any case, the formation of one layer of single crystal silicon thin film is completed in one process, and the manufacturing process can be significantly simplified.

Here, when the annealing treatment is performed by resistance heating, the substrate is placed on an appropriate supporting base, and the substrate placed in contact therewith is heated by heat conduction by heating the supporting base. The annealing method does not depend on the constituent material of the substrate. On the other hand, when the annealing treatment is performed by lamp annealing, the treatment method naturally differs depending on whether the substrate is light transmissive or light shielding.

That is, when the substrate is made of a light-transmissive material such as quartz (SiO ₂ ), the laser light and the annealing light reach the amorphous thin film or the polycrystalline thin film from both the front and back sides of the substrate. can do. Therefore, the laser light and the annealing light can be simultaneously irradiated from the front and back directions of the substrate. Of course, both lights may be emitted from the front side of the substrate or both of them from the back side. In this specification, the surface on which the amorphous thin film or the polycrystalline thin film is formed is called the front side, and the opposite side is called the back side.

On the other hand, when the substrate is made of a light-shielding material such as single crystal Si, the laser light and the annealing light can both be irradiated only from the front side.

Although the present invention is based on the above idea, a method for precisely controlling the size of the single crystallized region is also proposed. One of them is to completely amorphize a part of the amorphous thin film or the polycrystalline thin film by ion implantation prior to the nucleation by laser irradiation. An attempt to arbitrarily specify the position of nucleation by ion implantation is described in Extended Abstracts of the 22nd (1990 Intern
ational) Conference on Solid State Devices and Mate
rials, 1990, p.1159-1160. In this report, Si ⁺ is ion-implanted into an amorphous silicon thin film at a predetermined interval and then annealed at 600 ° C. to form a polycrystalline silicon thin film having a uniform grain size by crystal growth centered on this implantation site. ing. The present inventors focused on the fact that nuclei were most likely to be formed in such a thoroughly amorphized region, and applied ion implantation to the nucleation of the single crystal thin film in the present invention. That is, if ion implantation is performed at one place in a region where a single crystal thin film is to be formed, and laser light is irradiated onto the region to generate single crystal nuclei and at the same time nucleus growth by annealing treatment is performed, grain boundaries within the region are formed. It is possible to obtain a uniform single crystal thin film in which there is no

In the present invention, it is also proposed to perform laser irradiation through a photomask as a more simple method for specifying the nucleation position. As a result, it is possible to selectively irradiate a specific portion with the laser light and specify the nucleation position. In the above-mentioned ion implantation, it is necessary to form a resist mask on the amorphous thin film or the polycrystalline thin film by a photolithography technique to specify the ion implantation position.
Such complicated steps are not necessary at all.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below with reference to the drawings.

Example 1 In this example, amorphous silicon (a) on a quartz substrate is used.
-Si) When the thin film is single-crystallized, the front side of the wafer a-
This is an example in which excimer laser irradiation is performed from the Si thin film formation side) and lamp annealing is performed simultaneously from the back side (quartz substrate side). First, FIG. 1 shows a schematic configuration of the single crystallization apparatus used in this example.

This single crystallization apparatus 100 has a structure in which a laser light source 1 is arranged facing the front side of a wafer 6 placed on a wafer stage 2, and a high pressure mercury lamp 4 is arranged facing the back side. . In this figure, the light energy hν ₁ (h is Planck's constant, ν ₁ is wave number) emitted from the laser light source 1 is drawn so as to be uniformly incident on the wafer 6, but the actual laser light is not shown. Scanning is performed by using a mirror in a state where the beam is focused into a narrow beam by a lens included in the optical system. Here, KrF excimer laser light (249 nm) was used.

On the other hand, the annealing light emitted from the high-pressure mercury lamp 4 is efficiently introduced into the condenser lens 3 by using the reflecting mirror 5, and its light energy hν ₂ (h is Planck's constant, ν ₂ is wave number) is applied to the wafer. Irradiate 6 evenly from the back side. Here, the g-line (436 nm) was used.
Further, as is clear from the above configuration, the wafer stage 2 needs to be made of a material exhibiting a high light transmittance at the wavelength of the annealing light of the high pressure mercury lamp 4. Here, a wafer stage 2 made of quartz was used.

Next, an actual single crystallization process using the above single crystallization apparatus 100 will be described with reference to FIG. First, the wafer 6 used in this example is shown in FIG.
As shown in (a), an a-Si thin film 21 having a thickness of about 100 nm is formed on a transparent quartz substrate 20.

This wafer is set on the wafer stage 2 of the single crystallization apparatus 100 shown in FIG. 1, the wafer 6 is heated from the back side to 525 to 650 ° C. by the g line, and the KrF excimer laser irradiation is performed from the front side. went. Then, as shown in FIG. 2B, a-
A plurality of single crystal nuclei 22 are generated at random positions in the Si layer 21, and then the single crystal nuclei 2 are formed by lamp annealing.
Two-dimensional single crystallization centered on 2 proceeded.

Finally, as shown in FIG. 2C, the entire a-Si thin film 21 was changed to a single crystal Si thin film 23.

Example 2 This example is a single crystallization process of an a-Si thin film by the same KrF excimer laser irradiation and g-line lamp annealing. In this example, the controllability of the single crystal growth is enhanced by ion-implanting Si ⁺ into a part of the (shaped region) to make it completely amorphous. This process will be described with reference to FIG. Note that the reference numerals in FIG. 3 are partially common to those in FIG.

In this embodiment, first, the a-Si thin film 21 on the quartz substrate 20 as shown in FIG. 1A is patterned by a normal resist process and dry etching, and then the pattern shown in FIG. The a-Si island 21a corresponding to the formation region of each device was formed as shown in FIG. Furthermore, a resist coating film is formed on the entire surface of the wafer, and photolithography and development are performed to form a resist film.
The mask 23 was formed. This resist mask 23 is
One opening 24 is provided facing each a-Si island 21a.

Next, using the resist mask 23 as a mask, the dose amount is 1 × 10 ¹⁵ / cm ² , and the implantation energy is 7
When Si ⁺ was ion-implanted under the condition of ⁰ keV, a
-In the region of the Si island 21a exposed on the bottom surface of the opening 24, the structure is thoroughly amorphized,
Thorough amorphized region 2 as shown in FIG. 3 (b)
1b was formed.

Next, this wafer is processed into a single crystallization apparatus 1 shown in FIG.
00, and KrF excimer laser irradiation and g-line lamp annealing were performed in the same manner as in Example 1. Then, as shown in FIG. 3C, the single crystal nuclei 22 were selectively generated in the thoroughly amorphized region 21b, and the single crystal nuclei 22 grew in the two-dimensional direction. Figure 3 finally
As shown in (d), one a-Si island 21a was changed to a uniform single crystal Si island 23a.

In Example 1 described above, since the single crystal nuclei 22 were generated at random positions, the grown single crystal Si thin films 22 had non-uniform dimensions, and grain boundaries existed between the adjacent thin films. . On the other hand, when the generation position of the single crystal nucleus 22 is specified by Si ⁺ ion implantation, the size of the single crystal Si thin film 22 can be controlled. Particularly, if the number of single crystal nuclei 22 produced on each a-Si island 21a is limited to one as in the present embodiment, a single crystal Si thin film having no grain boundary in each island can be obtained. .

Example 3 This example is an example of performing KrF excimer laser irradiation through a photomask as a method for identifying the site where single crystal nuclei are formed in the a-Si thin film. FIG. 4 shows a schematic configuration of the single crystallization apparatus used in this example. Note that the reference numerals in FIG. 4 are partially common to those in FIG.
Descriptions of common parts are omitted to avoid duplication.

This single crystallizing apparatus 101 comprises a laser light source 1
And a wafer 6 with a photomask 7 interposed. As shown in FIG. 5B in an enlarged manner, a part of the photomask 7 is Cr formed in a predetermined pattern on a photomask substrate 8 made of a transparent material such as glass.
The light shielding film 9 made of a film or the like is formed. The light-shielding film 9 is provided with an opening 10 for specifying the site where the single crystal nucleus 22 is generated.

Further, in FIG. 4, the photomask 7 and the wafer 6 are illustrated as being separated from each other for convenience of explanation, but this does not mean that only the irradiation by the projection method using the projection optical system is taken into consideration. Without, for example, photomask 7
Irradiation by a contact method in which the wafer 6 and the wafer 6 are brought into close contact with each other or a proximity method in which the both are arranged in close proximity is also possible.

Next, a single crystallization process using this single crystallization apparatus 101 will be described. As shown in FIG. 5A, the wafer used here has an a-Si island 21a formed on the quartz substrate 20 through a predetermined patterning. This wafer was set in the single crystallizing apparatus 101, KrF excimer laser irradiation was performed from the front side through the photomask 7, and g-line lamp annealing was performed from the back side. In this step, as shown in FIG. 5B, each a- by the KrF excimer laser light that has passed through the opening 10 of the light shielding film 9 on the photomask 7.
Single crystal nuclei 22 were generated on the Si island 21a. At the same time, the nucleus growth centered on the single crystal nuclei 22 progressed by the annealing light irradiated from the back side.

Finally, a uniform single crystal Si island 23a was formed as shown in FIG. 5 (c).

Example 4 In this example, when an a-Si thin film laminated on a single crystal Si substrate via a SiO ₂ interlayer insulating film is single crystallized,
This is an example in which both the excimer laser irradiation and the lamp annealing are performed from the front side of the wafer. First, FIG. 6 shows a schematic configuration of the single crystallization apparatus used in this example. Note that the reference numerals in FIG. 6 are partially common to those in FIG.

This single crystallizing apparatus 102 includes a laser light source 1
Is arranged so as to face the wafer 11, and lamp annealing by the high pressure mercury lamp 4 can be performed obliquely above the wafer 11. The wafer stage in this case does not have to be made of a particularly transparent material. Further, the photomask 7 as described above may be interposed between the laser light source 1 and the wafer 11 if necessary.

Next, a single crystallization process using this single crystallization apparatus 102 will be described. In the wafer 11 used here, as shown in FIG. 7A, an a-Si thin film 32 having a thickness of about 100 nm is formed on a light-shielding single crystal Si substrate 30 via a SiO ₂ interlayer insulating film 31. It was done. The wafer 11 was set in the single crystallization apparatus 102, and KrF excimer laser irradiation and g-line lamp annealing were performed. The photomask 7 was not used here. As a result, as shown in FIG.
A plurality of single crystal nuclei 33 were generated in the Si thin film 33, and two-dimensional single crystallization proceeded around the single crystal nuclei 33.

Finally, as shown in FIG. 7C, the entire a-Si thin film 32 was changed to the single crystal Si thin film 34.

Also in this embodiment, if the Si.sup. ⁺ Ion implantation as described in the second embodiment is performed in advance or the laser irradiation through the photomask 7 as described in the third embodiment is performed, the single irradiation is performed. The generation site of the crystal nucleus 33 can be specified, and the dimensional controllability of the single crystallized region is further improved.

Embodiment 5 In this embodiment, the structure of the single crystallization device is devised so that both the laser light and the annealing light are irradiated onto the wafer at the same incident angle. First, FIG. 8 shows a schematic configuration of the single crystallization apparatus used in this example. The reference numerals in FIG. 8 are
It is partially common to FIG.

In this single crystallizing device 103, a high pressure mercury lamp 4 is arranged to face the wafer 11, and a dichroic mirror 12 is arranged on the optical path between the condenser lens 3 and the wafer 11. Annealing light emitted from the high-pressure mercury lamp 4 can pass through the dichroic mirror 12. On the other hand, the laser light source 1 and the high pressure mercury lamp 4 are arranged so that their optical paths are orthogonal to each other, and the laser light emitted from the laser light source 1 is reflected by the dichroic mirror 12.
It is adapted to be vertically incident on the wafer 11. A photomask (not shown) may be interposed on the optical path between the laser light source 1 and the dichroic mirror 12 if necessary.

This single crystallizing device 103 is also effective for single crystallizing an a-Si thin film on the light-shielding single crystal Si substrate 30, and almost the same result as in Example 4 was obtained.

Example 6 This example is an example in which the above-described single crystallization process is repeated twice to construct a three-dimensional device by the SOI technique. This process will be briefly described with reference to FIG. First, as shown in FIG. 9A, the quartz substrate 4
A first single crystal Si island 41 was formed on the upper surface of 0. This first single crystal Si island 41 is obtained by single crystallizing an a-Si thin film or a polycrystalline Si thin film. In this case, the method for producing the single crystal nuclei may be Si ⁺ ion implantation or laser irradiation through a photomask. Further, since the quartz substrate 40 is transparent, the lamp annealing can be performed from the back side at this stage, but in this embodiment, the single crystallizing apparatus shown in FIG. 6 or 8 was used to perform the lamp annealing from the front side. This is because in the second single crystallization process described later, the first light-shielding single crystal Si is formed on the wafer.
Since the island 41 has already been formed, the front side is more convenient for efficient lamp annealing.

Next, as shown in FIG. 9B, the entire surface of the wafer is thermally oxidized to form a gate oxide film, and then the polycrystalline silicon layer or the like is patterned to form the first gate electrode 4.
2 is formed, impurities are ion-implanted into the single crystal Si island 41 in a self-aligned manner using the first gate electrode 42 as a mask, and then the entire surface of the wafer is covered with the SiO ₂ interlayer insulating film 43.
Was flattened with.

Then, as shown in FIG. 9C, S
A _second single crystal Si island 44 was similarly formed on the i02 interlayer insulating film 43. The single crystallization method at this time is also the same as the case of forming the first single crystal Si island 41. Further, as shown in FIG. 9D, the entire surface of the wafer was thermally oxidized to form a gate oxide film, and then the polycrystalline silicon layer was patterned to form a second gate electrode 45. Impurities are ion-implanted into the second single crystal Si islands 44 in a self-aligning manner using the second gate electrode 45 as a mask, and then the entire surface of the wafer is covered with the SiO ₂ interlayer insulating film 4.
It was flattened at 6. After this, the second single crystal Si island 44 and the first
Facing the single crystal Si island 41 of each of the connection holes 4
8,49 were opened. Furthermore, these connection holes 48, 4
9 was embedded with an Al-based material layer or the like to form the upper wiring 49, thus completing the three-dimensional device.

Although the present invention has been described based on the six examples, the present invention is not limited to these examples. For example, in each of the above-described embodiments, the a-Si thin film is used as the thin film to be single-crystallized, but the same result can be obtained by using the polycrystalline Si thin film. Furthermore, if the type of the laser light source or the annealing light source is appropriately selected in consideration of the light absorption characteristics, the present invention can be applied to single crystallization of an amorphous thin film or a polycrystalline thin film made of a material other than Si.

As the light transmissive substrate, the quartz substrate is used in each of the above embodiments, but a substrate made of a dielectric material such as SiN _x may be used. As the annealing light, lamp annealing was adopted in all the examples, but this may be replaced by resistance heating. In the above-described Embodiments 2 and 3, the a-Si thin film is islanded before the single crystallization, but the islanding may be performed after the single crystallization. In this case, a single crystal nucleus may be generated at a specific site of the a-Si thin film and grown, and then a region including a grain boundary may be selectively removed by etching.

In the first to third embodiments described above, since the transparent quartz substrate 20 is used to form the wafer, the lamp annealing is all performed from the back side. As shown in FIG. 6 and FIG. Lamp annealing may be performed from the front side by using such single crystallizing devices 102 and 103. However, when the laser irradiation is performed through the photomask 7 as in the third embodiment, the lamp annealing can be performed from the front side only when the laser irradiation is performed by the projection method. In the contact method and the proximity method, since the photomask 7 is arranged in close contact with or close to the wafer, annealing light does not reach from the front side, and the photomask 7 is also thermally deformed.

Needless to say, the type of laser light source or annealing light source used, the configuration of the single crystallization apparatus, the configuration of the wafer, the configuration of the three-dimensional device, etc. can be changed as appropriate.

[0053]

As is apparent from the above description, if the present invention is applied to the single crystallization work, which was conventionally performed in two processes of nucleation and nucleation by separate devices, the single crystallization work is performed. It becomes possible to carry out in one process with one device. As a result, it is possible to significantly improve the productivity and the economic efficiency in manufacturing the semiconductor device. In addition, the present invention has a great industrial value as a technology that opens the way to mass production of three-dimensional devices to which the SOI technology is applied.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a configuration example of a single crystallization apparatus used in the present invention.

FIG. 2 is a schematic cross-sectional view showing an example of a process of applying the present invention to single-crystallize an a-Si thin film on a quartz substrate according to the order of steps, and FIG. 2 (a) shows a-Si thin film on a quartz substrate. The formed state, (b) is a state in which single crystal nuclei are formed in the a-Si thin film and nucleus growth is progressing, (c) is a-.
Each of the states in which the entire Si thin film is changed to a single crystal Si thin film is shown.

FIG. 3 is a schematic cross-sectional view showing another example of a process in which the present invention is applied to single-crystallize an a-Si thin film on a quartz substrate in the order of steps, and (a) is a resist on an a-Si island. A state in which Si ⁺ is ion-implanted through a mask, (b) is a state in which a thoroughly amorphized region is formed in a part of the a-Si island by ion implantation, and (c) is generation of single crystal nuclei. The state in which the nucleus growth is in progress and the state (d) in which the single crystal Si islands are formed are shown.

FIG. 4 is a schematic cross-sectional view showing another configuration example of the single crystallization device used in the present invention.

FIG. 5 is a schematic cross-sectional view showing still another process example of applying the present invention to single-crystallize an a-Si thin film on a quartz substrate in the order of steps, and (a) shows a- on the quartz substrate. A state where Si islands are formed, (b) a state where single crystal nuclei are formed in a part of the a-Si islands by laser irradiation through a photomask, and nucleus growth is progressing,
Each of (c) represents a state in which a single crystal Si island is formed.

FIG. 6 is a schematic cross-sectional view showing still another configuration example of the single crystallization device used in the present invention.

FIG. 7 is a diagram showing an example of applying SiO ₂ on a single crystal Si substrate according to the present invention.
Is a schematic sectional view showing a process example in which a single crystal of an a-Si thin film deposited on the interlayer insulating film according to the process order, through a SiO ₂ interlayer insulating film (a) is on a monocrystalline Si substrate a -Si thin film is formed, (b) is a
A state in which single crystal nuclei are formed in the -Si thin film and nucleus growth is progressing, and (c) shows a state in which the entire a-Si thin film is changed to the single crystal Si thin film.

FIG. 8 is a schematic cross-sectional view showing still another configuration example of the single crystallization device used in the present invention.

FIG. 9 is a schematic cross-sectional view showing an example of a process of forming a three-dimensional device to which the present invention is applied in the order of steps, in which (a) is a state in which a first single crystal Si island is formed on a quartz substrate. , (B), the first gate electrode is formed on the first single crystal Si island, and the entire surface of the wafer is S.
A state of being flattened by an SiO ₂ interlayer insulating film, (c) is SiO
_In the state where the second single crystal Si island is formed on the _two- layer insulating film, (d) shows that the second gate electrode is formed on the second single-crystal Si island and flattening by the SiO ₂ interlayer insulating film is performed. A state in which an upper layer wiring has been formed is shown.

[Explanation of symbols]

1 ... Laser light source 2 ... Wafer stage 3 ... Condenser lens 4 ... High-pressure mercury lamp 6,11 ... Wafer 7 ... Photomask 12 ... Two-color mirror 20 ... -Quartz substrate 21,32 ... a-Si thin film 21a ... a-Si island 21b ... Thorough amorphization region 22,33 ... Single crystal nucleus 23,34 ... Single crystal Si thin film 23a. ..Single crystal Si island 30 ... single crystal Si substrate 100, 101, 102, 103 ... single crystallizing device

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[Procedure amendment]

[Submission date] August 13, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

Title: Method for manufacturing semiconductor device

[Claims]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and in particular, a single crystal silicon thin film for forming a channel region of a thin film transistor is formed by a simple method.
The present invention relates to a method for manufacturing a semiconductor device that can be used for mass production of three-dimensional devices by OI technology.

[0002]

2. Description of the Related Art Melt recrystallization by laser irradiation has been studied for the purpose of improving the crystallinity of polycrystalline silicon on an insulating film or growing a single crystal. In particular, a technique for growing a single crystal silicon thin film on a SiO ₂ substrate having excellent interface characteristics with silicon is SOI (Silicon-On-I).
It has a possibility of being able to manufacture an LSI at a low cost in a process highly compatible with a conventional semiconductor process. In addition, it is highly anticipated as a technology that can realize a three-dimensional device by stacking multiple active layers with an insulating film interposed therebetween.

In addition to silicon devices, thin film transistors (TFTs) formed on a glass substrate are considered as application fields of SOI technology. Among these, TF
T is used, for example, in constructing a matrix drive circuit of a liquid crystal display device. For a conventional TFT, the source /
In general, the drain region and the channel region are formed in an amorphous silicon thin film or a polycrystalline silicon thin film. However, a TFT formed by using these thin films as a base has (a) a large leak current, and there is a limit to high reliability of operation and reduction of power consumption, and (b) operation with low carrier mobility. There is a limit to the speedup of
(C) Problems such as that the channel length is approaching the crystal grain size with the miniaturization of the design rule, and the device characteristics of the TFT are likely to vary particularly when a polycrystalline silicon thin film is used. There is.

Therefore, in order to further increase the speed and reliability of the TFT in the future, it is necessary to use a structurally uniform single crystal silicon thin film having no crystal grain boundary as a base.

[0005]

However, in such a conventional method, it is necessary to perform nucleation and nucleation in different steps using different devices, and it is desired to greatly improve productivity and economic efficiency. It is not possible. This makes the manufacturing process extremely complicated when, for example, manufacturing a three-dimensional device using TFTs by laminating several single-crystal silicon thin films with an interlayer insulating film interposed therebetween. Is also an obstacle.

Therefore, the present invention makes it possible to form a single crystal thin film with a simple device and process, greatly improve productivity and economic efficiency, and mass-produce semiconductor devices having a complicated three-dimensional structure. The purpose is to provide a possible method.

[0007]

A method of manufacturing a semiconductor device of the present invention is proposed to achieve the above-mentioned object, and crystallizes an amorphous thin film or a polycrystalline thin film formed on a substrate. When this is done, the formation of nuclei by laser irradiation and the growth of nuclei by an annealing treatment are carried out at the same time, whereby substantial single crystallization is carried out. The annealing treatment in this case may be lamp annealing or resistance heating.
When the above-mentioned annealing treatment is performed by resistance heating, the substrate is placed on an appropriate supporting base, and the substrate placed in contact therewith is heated by heat conduction through heating of this supporting base. It does not depend on the constituent material of the substrate. On the other hand, when the annealing treatment is performed by lamp annealing, the treatment method naturally differs depending on whether the substrate is light transmissive or light shielding.

Here, when the substrate is light transmissive,
The laser light and the annealing light can reach the amorphous thin film or the polycrystalline thin film from either the front side or the back side of the substrate. Therefore, the laser light and the annealing light can be simultaneously irradiated from the front and back directions of the substrate. Of course, both lights may be emitted from the front side of the substrate or both of them from the back side. In this case, a silicon oxide type material or a silicon nitride type material is suitable as a constituent material of the light transmissive substrate, and a silicon type material is practically important as the amorphous thin film or the polycrystalline thin film. In this specification, the surface on which the amorphous thin film or the polycrystalline thin film is formed is called the front side, and the opposite side is called the back side.

On the other hand, when the substrate has a light-shielding property, both the laser light and the annealing light can be irradiated only from the front side. In this case, the constituent material of the light-shielding substrate may be a silicon-based material having a surface coated with an insulating material, and the amorphous thin film or the polycrystalline thin film may be composed of a silicon-based material. is important.

Prior to the nucleation, a portion other than the nucleation position on the amorphous thin film or the polycrystalline thin film may be annealed by ion beam irradiation.

Furthermore, if the laser irradiation is performed through a photomask, nucleation can be selectively performed at any position on the amorphous thin film or the polycrystalline thin film.

[0012]

In the present invention, the laser irradiation for nucleation and the annealing treatment for nuclei growth are performed simultaneously by using the apparatus equipped with both the laser irradiation mechanism and the annealing treatment mechanism. The formation of the chemical thin film can be completed in one process. Therefore, the manufacturing process can be significantly simplified.

Further, depending on whether the substrate is light-transmitting or light-shielding, it is naturally decided whether the laser light or the annealing light should arrive from the front side or the back side of the substrate. In any case, the above process is performed. Only one manufacturing device is required.

Further, a portion other than the nucleation position on the amorphous thin film or the polycrystalline thin film is annealed by ion beam irradiation in advance to realize a single crystal grain growth in which grain boundaries are not regularly arranged. can do.

If the laser irradiation is performed through a photomask, the nucleation position can be specified more easily. In other words, selectively irradiate a specific region with laser light,
The nucleation position can be specified. In the above-mentioned ion beam annealing, it is necessary to form a resist mask on the amorphous thin film or the polycrystalline thin film by photolithography technology in order to identify the ion beam irradiation site. If
Such complicated steps are not necessary at all.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below with reference to the drawings.

Example 1 In this example, amorphous silicon (a) on a quartz substrate is used.
-Si) When crystallizing a thin film, the front side (a-
This is an example in which excimer laser irradiation is performed from the Si thin film formation side) and lamp annealing is performed simultaneously from the back side (quartz substrate side). First, FIG. 1 shows a schematic structure of the crystallization apparatus used in this example.

The crystallizing apparatus 100 has a structure in which a laser light source 1 is arranged facing the front side of a wafer 6 placed on a wafer stage 2, and a short wavelength arc lamp 4 is arranged facing the back side. Have. In this figure, the light energy hν ₁ emitted from the laser light source ₁ (h is Planck's constant,
ν ₁ is a wave number) so that it is uniformly incident on the wafer 6, but the actual laser beam is narrowed into a narrow beam by a lens included in an optical system (not shown) and is scanned using a mirror. To be done. Here, KrF excimer laser light (249 nm) was used.

On the other hand, the annealing light emitted from the arc lamp 4 is efficiently introduced into the condenser lens 3 by using the reflecting mirror 5, and the light energy hν ₂ (h is Planck's constant, ν ₂ is wave number) of the wafer. 6 is heated uniformly from the back side. Also, as is clear from the above configuration,
The wafer stage 2 needs to be made of a material having a high light transmittance at the wavelength of the annealing light of the arc lamp 4. Here, a wafer stage 2 made of quartz was used.

Next, an actual crystallization process using the above crystallization apparatus 100 will be described with reference to FIG. First, the wafer 6 used in this example is shown in FIG.
As shown in (a), an a-Si thin film 21 having a thickness of about 100 nm is formed on a transparent quartz substrate 20.

This wafer is set on the wafer stage 2 of the crystallization apparatus 100 of FIG. 1, the wafer 6 is heated to 525 to 650 ° C. from the back side by the arc lamp 4, and the KrF excimer laser is irradiated from the front side. I went.
Then, as shown in FIG. 2B, a plurality of crystal nuclei 22 are generated at random positions in the a-Si layer 21 due to the laser irradiation, and the crystal nuclei 22 are subsequently formed by lamp annealing. The two-dimensional single crystal grain growth centered on the center of the surface proceeded.

Finally, as shown in FIG. 2 (c), the entire a-Si thin film 21 was changed to a substantially single crystal Si thin film 23.

Example 2 This example is also a crystallization process of an a-Si thin film by KrF excimer laser irradiation and short wavelength arc lamp annealing. This is an example in which the controllability of single crystal grain growth is improved by performing Si ⁺ ion beam annealing on a part of (island region). This process will be described with reference to FIG. The reference numerals in FIG. 3 are the same as those in FIG.
And is partly common.

In this embodiment, first, the a-Si thin film 21 on the quartz substrate 20 as shown in FIG. 1A is patterned by a normal resist process and dry etching, and then the pattern shown in FIG. The a-Si island 21a corresponding to the formation region of each device was formed as shown in FIG. Furthermore, a resist coating film is formed on the entire surface of the wafer, and photolithography and development are performed to form a resist
The mask 24 was formed. This resist mask 24 is
One is formed on each a-Si island 21a.

Next, when Si ⁺ ion beam annealing was performed through the resist mask 24, a-
The exposed region of the Si island 21a is heated, and as shown in FIG.
The heating region 21b as shown in (b) was formed.

Next, the wafer is crystallized from the crystallization apparatus 10 shown in FIG.
0 was set, and KrF excimer laser irradiation and arc lamp annealing were performed as in Example 1. Then, as shown in FIG. 3C, crystal nuclei 22 are selectively generated in the remaining a-Si islands 21a that have not been subjected to the ion beam annealing, and the crystal nuclei 22 grow in a two-dimensional direction. . Finally, as shown in FIG. 3D, each single a-Si island 21a was changed to a substantially single crystal Si island 23a.

In the first embodiment described above, since the crystal nuclei 22 are generated at random positions, the grown single crystal Si thin films 2 are formed.
The size of No. 3 was non-uniform, and grain boundaries existed between the adjacent thin films. On the other hand, when the generation position of the crystal nucleus 22 is specified by Si ⁺ ion beam annealing, the size of the single crystal Si thin film 23 can be controlled. In particular,
If the number of crystal nuclei 22 produced on each a-Si island 21a is limited to one as in the present embodiment, a Si thin film having no grain boundary in each island can be obtained.

Example 3 In this example, similarly, as a method for identifying the site where crystal nuclei are formed in the a-Si thin film, K is applied through a photomask.
This is an example of irradiation with rF excimer laser. The schematic structure of the crystallization apparatus used in this example is shown in FIG.
Note that the reference numerals in FIG. 4 are partially common to those in FIG. 1, and the description of the common portions is omitted to avoid duplication.

The crystallization apparatus 101 has a structure in which a photomask 7 is interposed between the laser light source 1 and the wafer 6. As shown in FIG. 5B in a partially enlarged manner, the photomask 7 is a light-shielding film made of a Cr film or the like formed in a predetermined pattern on a photomask substrate 8 made of a transparent material such as glass. 9 is formed. The light-shielding film 9 is provided with an opening 10 for specifying the generation site of the crystal nucleus 22.

Further, in FIG. 4, the photomask 7 and the wafer 6 are illustrated as being separated from each other for convenience of explanation, but this does not mean that only irradiation by the projection method using the projection optical system is taken into consideration. Without, for example, photomask 7
Irradiation by a contact method in which the wafer 6 and the wafer 6 are brought into close contact with each other or a proximity method in which the both are arranged in close proximity is also possible.

Next, a crystallization process using the crystallization device 101 will be described. As shown in FIG. 5A, the wafer used here has an a-Si island 21a formed on the quartz substrate 20 through a predetermined patterning. This wafer is used as the crystallization device 10
1 and set Kr from the front side through the photomask 7.
F excimer laser irradiation was performed, and g-line lamp annealing was performed from the back side. In this step, as shown in FIG. 5B, the opening 10 of the light shielding film 9 on the photomask 7 is formed.
Each a-Si by the KrF excimer laser light that has passed through
Crystal nuclei 22 were generated on the island 21a. At the same time, the nucleus growth centered on the crystal nucleus 22 progressed by the annealing light emitted from the back side.

Finally, as shown in FIG. 5C, a substantial single crystal Si island 23a was formed.

Example 4 In this example, when crystallizing an a-Si thin film laminated on a single crystal Si substrate via an SiO ₂ interlayer insulating film, both excimer laser irradiation and lamp annealing are performed. This is an example performed from the front side of the wafer. First, FIG. 6 shows a schematic configuration of the crystallization apparatus used in this example. Note that the reference numerals in FIG. 6 are partially common to those in FIG.

The crystallizing apparatus 102 is arranged such that the laser light source 1 is arranged so as to face the wafer 11 and that lamp annealing can be performed on the wafer 11 obliquely from above by the arc lamp 4. The wafer stage in this case does not have to be made of a particularly transparent material. Further, the photomask 7 as described above may be interposed between the laser light source 1 and the wafer 11 if necessary.

Next, a crystallization process using the crystallization device 102 will be described. Wafer 1 used here
As shown in FIG. 7A, 1 is a light-shielding single crystal S
The a-Si thin film 32 having a thickness of about 100 nm is formed on the i substrate 30 with the SiO ₂ interlayer insulating film 31 interposed therebetween. The wafer 11 was set in the crystallization device 102, and KrF excimer laser irradiation and arc lamp annealing were performed. The photomask 7 was not used here. As a result, as shown in FIG.
A plurality of crystal nuclei 33 were generated in the —Si thin film 33, and two-dimensional single crystal grain growth proceeded around the crystal nuclei 33.

Finally, as shown in FIG. 7C, the entire a-Si thin film 32 was changed to a substantially single crystal Si thin film 34.

Also in this embodiment, the Si ⁺ ion beam irradiation as described in the second embodiment is performed in advance, or
Alternatively, by performing laser irradiation through the photomask 7 as described in Example 3, the generation site of the crystal nucleus 33 can be specified, and the dimensional controllability and position controllability of the crystallization region are further improved.

Embodiment 5 In this embodiment, the structure of the crystallization device is devised so that both the laser light and the annealing light are irradiated onto the wafer at the same incident angle. First, FIG. 8 shows a schematic structure of the crystallization apparatus used in this example. The reference symbols in FIG. 8 are the same as those in FIG.
And is partly common.

In this crystallization device 103, the arc lamp 4 is arranged so as to face the wafer 11, and the condenser lens 3 is used.
A two-color mirror 12 is arranged on the optical path between the wafer 11 and the wafer 11. The annealing light emitted from the arc lamp 4 can pass through this dichroic mirror 12. On the other hand, the laser light source 1 is arranged so that the optical path is orthogonal to the arc lamp 4, and the laser light emitted from the laser light source 1 is reflected by the dichroic mirror 12.
It is adapted to be vertically incident on the wafer 11. A photomask (not shown) may be interposed on the optical path between the laser light source 1 and the dichroic mirror 12 if necessary.

This crystallizing device 103 is also effective for crystallizing the a-Si thin film on the light-shielding single crystal Si substrate 30, and almost the same result as in Example 4 was obtained.

Embodiment 6 This embodiment is an example in which the crystallization process as described above is repeated twice to construct a three-dimensional device by the SOI technique. This process will be briefly described with reference to FIG. First, as shown in FIG. 9A, the quartz substrate 40
A first single crystal Si island 41 was formed on top. The first single crystal Si island 41 is obtained by crystallizing an a-Si thin film or a polycrystalline Si thin film. In this case, the method of generating crystal nuclei may be Si ⁺ ion beam annealing or laser irradiation via a photomask. Further, since the quartz substrate 40 is transparent, the lamp annealing can be performed from the back side at this stage, but in this embodiment, it was performed from the front side using the crystallization apparatus shown in FIG. 6 or 8. This is because when the second crystallization process described below is performed, the light-shielding first
Since the single crystal Si island 41 is already formed, the front side is more convenient for efficient lamp annealing.

Next, as shown in FIG. 9B, the entire surface of the wafer is thermally oxidized to form a gate oxide film, and then the polycrystalline silicon layer or the like is patterned to form the first gate electrode 4.
2 was formed, and the single crystal Si island 41 was ion-beam-irradiated with impurities by using the first gate electrode 42 as a mask in a self-aligned manner, and then the entire surface of the wafer was flattened by the SiO ₂ interlayer insulating film 43.

Then, as shown in FIG. 9C, S
A _second single crystal Si island 44 was similarly formed on the iO ₂ interlayer insulating film 43. The crystallization method at this time is also the first
This is similar to the case of forming the single crystal Si island 41. Further, as shown in FIG. 9D, the entire surface of the wafer was thermally oxidized to form a gate oxide film, and then the polycrystalline silicon layer was patterned to form a second gate electrode 45. After the second single crystal Si island 44 was ion-beam-irradiated with impurities by self-alignment using the second gate electrode 45 as a mask, the entire surface of the wafer was flattened with an SiO ₂ interlayer insulating film 46. After that, the connection holes 47 and 48 were opened so as to face the second single crystal Si island 44 and the first single crystal Si island 41 by a normal contact formation process. Furthermore, these connection holes 4
7 and 48 are embedded with an Al-based material layer or the like to form the upper wiring 4
9 was formed to complete the three-dimensional device.

Although the present invention has been described based on the six examples, the present invention is not limited to these examples. For example, in each of the above-described embodiments, the a-Si thin film is used as the thin film to be crystallized, but substantially the same result can be obtained by using the polycrystalline Si thin film. Further, the present invention can be applied to crystallization of an amorphous thin film or a polycrystalline thin film made of a material other than Si by appropriately selecting the type of laser light source or annealing light source in consideration of light absorption characteristics.

As the light transmissive substrate, the quartz substrate is used in each of the above embodiments, but a substrate made of a dielectric material such as SiN _x may be used. As the annealing light, lamp annealing was adopted in all the examples, but this may be replaced by resistance heating. In the above-described Embodiments 2 and 3, the a-Si thin film is islanded before crystallization, but islanding may be performed after crystallization. In this case, after a crystal nucleus is generated at a specific portion of the a-Si thin film and grown, the region including the grain boundary may be selectively removed by etching.

In the above-mentioned first to third embodiments, since the transparent quartz substrate 20 is used to form the wafer, the lamp annealing is all performed from the back side. As shown in FIG. 6 and FIG. Lamp annealing may be performed from the front side by using such crystallization devices 102 and 103. However, when the laser irradiation is performed through the photomask 7 as in the third embodiment, the lamp annealing can be performed from the front side only when the laser irradiation is performed by the projection method. In the contact method and the proximity method, since the photomask 7 is arranged in close contact with or close to the wafer, annealing light does not reach from the front side, and the photomask 7 is also thermally deformed.

Needless to say, the type of laser light source or annealing light source used, the structure of the crystallization apparatus, the structure of the wafer, the structure of the three-dimensional device, etc. can be changed as appropriate.

[0048]

As is apparent from the above description, if the present invention is applied to the crystallization work which has conventionally been performed by using two separate devices, the nucleation and the nucleation, which are divided into two processes. It becomes possible to carry out in one process using a single apparatus. As a result, it is possible to significantly improve the productivity and the economic efficiency in manufacturing the semiconductor device. In addition, the present invention has a great industrial value as a technology that opens the way to mass production of three-dimensional devices to which the SOI technology is applied.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing one structural example of a crystallization device used in the present invention.

2A and 2B are schematic cross-sectional views showing an example of a process of crystallizing an a-Si thin film on a quartz substrate according to the present invention in the order of steps, wherein FIG. (B) is a state in which crystal nuclei are formed in the a-Si thin film and nucleus growth is in progress, and (c) is a-Si.
Each of the states in which the entire thin film is changed to a substantially single crystal Si thin film is shown.

FIG. 3 is a schematic cross-sectional view showing another example of the process of crystallizing an a-Si thin film on a quartz substrate according to the order of steps, to which the present invention is applied. The state where Si ⁺ ion beam annealing is performed through the mask, (b) shows the ion beam
A heating region is formed in a part of the a-Si island by annealing, (c) is a state in which crystal nucleus generation and nucleus growth are in progress, and (d) is a state in which a single crystal Si island is formed. Represent each.

FIG. 4 is a schematic cross-sectional view showing another configuration example of the crystallization device used in the present invention.

FIG. 5 is a schematic cross-sectional view showing yet another process example of crystallizing an a-Si thin film on a quartz substrate according to the order of steps, to which the present invention is applied.
-Si islands are formed, (b) is a state in which crystal nuclei are formed in a part of the a-Si islands by laser irradiation through a photomask and nucleus growth is progressing,
Each of (c) represents a state in which a single crystal Si island is formed.

FIG. 6 is a schematic cross-sectional view showing still another configuration example of the crystallization device used in the present invention.

FIG. 7 is a diagram showing an example of applying SiO ₂ on a single crystal Si substrate according to the present invention.
Is a schematic sectional view showing an example process of crystallizing the a-Si thin film deposited on the interlayer insulating film according to the order of steps, (a) shows the through SiO ₂ interlayer insulation film on a single crystal Si substrate a- The state where the Si thin film is formed, (b) is a-
A state in which crystal nuclei are formed in the Si thin film and nucleus growth is progressing, (c) shows that the entire a-Si thin film is substantially single crystal Si
The state of the thin film is shown.

FIG. 8 is a schematic cross-sectional view showing still another configuration example of the crystallization device used in the present invention.

FIG. 9 is a schematic cross-sectional view showing an example of a process of forming a three-dimensional device to which the present invention is applied in the order of steps, in which (a) is a state in which a first single crystal Si island is formed on a quartz substrate. , (B), the first gate electrode is formed on the first single crystal Si island, and the entire surface of the wafer is S.
A state of being flattened by an SiO ₂ interlayer insulating film, (c) is SiO
_In the state where the second single crystal Si island is formed on the _two- layer insulating film, (d) shows that the second gate electrode is formed on the second single-crystal Si island and flattening by the SiO ₂ interlayer insulating film is performed. A state in which an upper layer wiring has been formed is shown.

[Explanation of Codes] 1 ... Laser light source 2 ... Wafer stage 3 ... Condenser lens 4 ... Arc lamp 6,11 ... Wafer 7 ... Photomask 12 ... Two-color mirror 20 ... Quartz substrate 21, 32 ... A -Si thin film 21a ... a-Si island 21b ... Heating region 22,33 ... Crystal nucleus 23,34 ... Single crystal Si thin film 23a ... Single crystal Si island 30 ... Single crystal Si Substrate 100, 101, 102, 103 ... Crystallizing device

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 3

[Correction method] Change

[Correction content]

[Figure 3]

Claims (8)

[Claims] 1. A method for manufacturing a semiconductor device in which an amorphous thin film or a polycrystalline thin film formed on a substrate is monocrystallized to form a single crystal thin film, wherein nucleation by laser irradiation and nucleation by annealing treatment are performed. A method for manufacturing a semiconductor device, characterized in that the single crystal thin film is formed by carrying out at the same time. 2. A method of manufacturing a semiconductor device in which an amorphous thin film or a polycrystalline thin film formed on a light transmissive substrate is monocrystallized to form a single crystal thin film, wherein laser irradiation and nuclei for forming nuclei are used. A method of manufacturing a semiconductor device, wherein the single crystal thin film is formed by simultaneously performing annealing treatment for growth on the substrate from directions in which the substrates are in a front-back relationship. 3. A method of manufacturing a semiconductor device in which an amorphous thin film or a polycrystalline thin film formed on a light transmissive substrate is monocrystallized to form a single crystal thin film, wherein laser irradiation and nuclei for forming nuclei are used. A method of manufacturing a semiconductor device, characterized in that lamp annealing for growth is performed from the same side with respect to the main surface of the substrate. 4. The light transmissive substrate is made of a silicon oxide material or a silicon nitride material, and the amorphous thin film or polycrystalline thin film is made of a silicon material. 3. The method for manufacturing a semiconductor device according to 3. 5. A method for manufacturing a semiconductor device in which an amorphous thin film or a polycrystalline thin film formed on a light-shielding substrate is single-crystallized to form a single-crystal thin film. A method of manufacturing a semiconductor device, characterized in that the lamp annealing for performing the above is performed from the side of the substrate on which the amorphous thin film or the polycrystalline thin film is formed. 6. The light-shielding substrate is made of a silicon-based material whose surface is coated with an insulating material, and the amorphous thin film or the polycrystalline thin film is made of a silicon-based material. A method for manufacturing a semiconductor device as described above. 7. Prior to the nucleation, any position on the amorphous thin film or the polycrystalline thin film is thoroughly amorphized by ion implantation.
7. The method for manufacturing a semiconductor device according to claim 6. 8. The nucleation is selectively performed at an arbitrary position on the amorphous thin film or the polycrystalline thin film by performing the laser irradiation through a photomask. 7. The method for manufacturing a semiconductor device according to any one of 6 above.