JP2000277429A - Manufacture of thin-film element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a polysilicon layer of a large crystal particle size in a channel region, related to a thin-film element used as a switching element of an active matrix liquid-crystal display. SOLUTION: An amorphous silicon film 2 is formed on a glass substrate 1, on which a glass film 3 is formed. A modulation region 4 is so formed that the optical property of the glass film 3 at least changes in the direction parallel to the surface of the glass substrate 1. A laser beam 5 is made incident on the glass film 3, whose intensity distribution is modulated with the glass film 3 and made incident on the amorphous silicon film 2, so that the amorphous silicon film is poly-crystallized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a thin film element used as a switching element in an active matrix type liquid crystal display (LCD).

[0002]

2. Description of the Related Art A thin film electronic device represented by a thin film transistor (TFT) is used as a switching element for driving each of a plurality of pixels arranged in a matrix on an array substrate made of a glass substrate in a liquid crystal display. Used. In general, amorphous (amorphous) silicon is used for an operation semiconductor layer (channel layer) of a thin film electronic element formed on an array substrate. In recent years, polysilicon (polycrystalline silicon) is used as an operation semiconductor layer. Thin film transistors are also being manufactured. Further, the application range of a manufacturing process of a thin-film electronic device using polysilicon as an operation semiconductor layer is also expanding. For example, a driver IC for driving and controlling a thin film transistor by supplying a gate signal to a gate bus line on an array substrate is conventionally formed on a single crystal wafer by a completely different process from the manufacture of a thin film transistor. It has become possible to simultaneously form a driver IC on an array substrate in a manufacturing process for forming a polysilicon TFT thereon.

[0003] In particular, relatively low temperatures (eg, 600 °
C or less), the low-temperature polysilicon TFT manufacturing process of forming a polysilicon layer can form a polysilicon thin film on an inexpensive glass substrate with low heat resistance.
It is highly expected as a method for manufacturing a next-generation active matrix type liquid crystal display in which a large number of thin film electronic elements are formed on an array substrate.

In this low-temperature polysilicon TFT manufacturing technology, it is necessary to form a polysilicon layer having good crystallinity within a range of a thermal load allowed by an alkali-free glass substrate or the like having a lower heat resistance than quartz or the like. There is. A conventional low-temperature polysilicon manufacturing process will be briefly described with reference to FIG. FIG. 10 shows a partial cross section of the substrate cut in a direction perpendicular to the glass substrate surface. First, an amorphous silicon (a-Si) film 2 is formed on a substrate 1 such as glass using a plasma CVD method or the like. Next, the substrate 1 is irradiated with the laser light 5 using an excimer laser capable of irradiating an ultraviolet light having a large absorption in the a-Si film 2, and only the amorphous silicon film is selectively melted and polycrystallized.

[0005] Usually, the intensity of the laser beam 5 to be applied is extremely strong, reaching a high temperature enough to melt silicon. Therefore, in order to prevent the glass substrate 1 from being damaged, the irradiation of the laser beam is completed within 300 nanoseconds.

However, in this method, since the irradiation time of the laser light 5 is extremely short, the heat of the silicon layer 2 generated by the irradiation of the laser light 5 is conducted to the glass substrate in a short time, and the molten silicon Quickly cools down. This rapid cooling causes crystal nuclei to be randomly generated in the crystal growth of silicon and also increases the nucleation density, so that the crystal grain size of silicon obtained by this method is reduced. ing. In a TFT channel formed of polysilicon having a small crystal grain size, it is difficult to obtain high mobility of carriers.

In order to solve this problem, the spatial intensity distribution of the laser beam 5 is modulated by using an optical element (not shown) such as a phase shift mask so that the temperature distribution in the plane of the a-Si film 2 is reduced. There is known a method of generating crystals having a large grain size by lowering a substantial cooling rate. In this method, the position where large crystal grains are obtained in the direction of the substrate surface in the silicon film 2 depends on the spatial distribution of the laser light 5.
Therefore, it is necessary to precisely align (align) the optical element when irradiating the laser 5 so that a crystal having a large grain size is located in a channel region of a thin film electronic element such as a TFT.

[0008]

However, since the optical element is arranged at a distance from the substrate 1 and the distance from the substrate 1 is extremely long compared to the width of a channel region to be formed, the optical element on the substrate 1 It is extremely difficult to align an optical element in accordance with a channel region in an element formation region, and a problem arises in that a high-precision precision mechanical device must be used, which causes a rise in manufacturing cost. Excimer lasers (including gas lasers such as argon lasers), which are generally used as light sources, have a laser medium in a gaseous phase, so that the traveling direction and spatial intensity distribution of laser light are likely to change with time, There is also a problem that it is difficult to irradiate the thin film electronic element with laser light with an appropriate intensity distribution.

An object of the present invention is to provide a method of manufacturing a thin film element capable of forming a polysilicon layer having a large crystal grain size in a channel region. Another object of the present invention is to provide a method of manufacturing a thin film element that can be accurately and easily aligned when a polysilicon layer is formed in a channel region. It is a further object of the present invention to provide a method for manufacturing a thin film element suitable for use in an active matrix type liquid crystal display or the like.

[0010]

The object of the present invention is to provide a method of manufacturing a thin film element formed on an insulating substrate, comprising the steps of: forming an amorphous silicon film on the insulating substrate; Forming a glass film on the glass substrate, changing the optical properties of the glass film at least in a direction parallel to the surface of the insulating substrate, and irradiating the glass film with light, and distributing the intensity distribution of the light with the glass film. Modulating the light to make it incident on the amorphous silicon film and crystallizing the amorphous silicon film.

[0011] It is another object of the present invention to provide a method of manufacturing a thin film element formed on an insulating substrate, wherein the step of forming a glass film on the insulating substrate and the optical property of the glass film are performed at least on the surface of the insulating substrate. A step of changing in a direction parallel to, and a step of forming an amorphous silicon film on the glass film,
Light incident on the glass film, modulating the intensity distribution of the light with the glass film and incident on the amorphous silicon film, and crystallizing the amorphous silicon film. This is achieved by a manufacturing method.

In the method of manufacturing a thin film element according to the present invention, an ion exchange method can be used in the step of changing the optical properties of the glass film. Further, an ion implantation method may be used in the step of changing the optical properties of the glass film.
Further, in the step of changing the optical properties of the glass film, an alignment mark for positioning may be formed in the glass film at the same time. Further, the glass film may be formed to include a silicon-based oxide.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for manufacturing a thin film device according to a first embodiment of the present invention will be described with reference to FIG. FIG.
2 shows a partial cross section of the substrate cut in a direction perpendicular to the glass substrate surface. First, in FIG. 1A, a silicon film 2 is formed on a substrate 1. As the substrate 1, a glass substrate is usually used. The silicon film 2 is provided for forming a channel region of the thin film electronic device, and is formed by plasma CVD.
After being formed as a non-amorphous film by a method or the like, it is crystallized by irradiation with a laser beam. On the silicon film 2, a glass film 3 containing silicon oxide (SiO2) is formed. The glass film 3 functions as an optical element that modulates and transmits the intensity distribution of the laser light. For this reason, the glass film 3 is provided with a modulation region 4 whose optical properties are changed. The modulation region 4 of the glass film 3 has a different refractive index from the other regions of the glass film 3 and is formed, for example, so that the intensity of laser light transmitted through the modulation region 4 is higher than that of the other regions. Have been.

Next, as shown in FIG. 1B, a laser beam 5 is irradiated in a direction from the glass film 3 to the substrate 1. Laser light 5 incident on glass film 3 functioning as an optical element
Is made to have an intensity distribution whose intensity is spatially modulated by a modulation region 4 formed in the optical element of the glass film 3. The laser light 5 converted into an uneven intensity distribution in a plane parallel to the surface of the substrate 1 is emitted from the glass film 3 and enters the amorphous silicon film 2. The amorphous silicon film 2 receives heat from the laser beam 5 and generates heat to generate a temperature distribution inside the film. This temperature distribution is shown as a change in density in FIG. 1B, and is not uniform in a plane parallel to the surface of the substrate 1 corresponding to the intensity distribution of the laser beam. Therefore, solidification starts gradually in the silicon film 2 from a low temperature region, and crystals grow in a direction parallel to the surface of the substrate 1 to obtain large crystal grains. In FIG. 1B, two modulation regions 4 are shown, and the growth of crystals proceeds in a direction parallel to the surface of the substrate 1 from the silicon film 2 immediately below these modulation regions 4 by shading. .

As described above, according to the method of manufacturing a thin film element according to the present embodiment, first, the problem of the conventional method using no optical element can be solved. That is, in the conventional method shown in FIG. 10, even if the laser beam 5 is irradiated, the heat of the molten silicon is almost conducted to the substrate 1 in a short time and escapes from the silicon film 2 and is formed in the silicon film 2. Although the crystal grains of the polysilicon have become smaller, such a problem cannot occur in the present embodiment. Second, in the present embodiment, since the glass film 3 functioning as an optical element can be stably arranged close to the silicon film 2 as a workpiece, it is possible to reduce the difficulty of alignment as in the related art. Can be. Therefore, it is possible to suppress the manufacturing cost without using a high-precision positioning precision machine. Third, in the present embodiment, since the modulation region 4 for forcibly changing the light intensity distribution is formed in the glass film 3, the deflection of the laser light of a gas laser such as an excimer laser and the temporal change of the intensity distribution are obtained. The effect of the change can be suppressed.

Next, a method of manufacturing a thin film device according to a second embodiment of the present invention will be described with reference to FIG. FIG.
Components having the same functions and functions as those of the first embodiment described using the same reference numerals are denoted by the same reference numerals, and description thereof will be omitted. FIG. 2 shows a partial cross section of the substrate cut in a direction perpendicular to the glass substrate surface. The present embodiment is characterized in that a glass film 3 functioning as an optical element is provided between a silicon film 2 as a workpiece and a glass substrate 1.

First, a glass film 3 is formed on a substrate 1 shown in FIG. As the substrate 1, a glass substrate is used. Usually, the glass substrate is made of not only silicon oxide but also a mixture of various metal oxides such as aluminum and barium. For this reason, it is not preferable that these elements diffuse into the silicon film 2 formed on the substrate 1. Therefore, a glass film such as a silicon oxide film is formed between the substrate 1 and the silicon film 2 as a barrier layer. In the present embodiment, the element structure is simplified by using the glass film 3 as the barrier layer as an optical element.

The glass film 3 functions as an optical element that modulates the intensity distribution of the laser light and transmits the same, as in the first embodiment. For this reason, the glass film 3 is provided with a modulation region 4 whose optical properties are changed. The modulation region 4 of the glass film 3
It has a different refractive index from the other regions, and is formed, for example, so that the intensity of the laser beam transmitted through the modulation region 4 is higher than the other regions.

As shown in FIG. 2A, a laser beam 5 is irradiated in a direction from the substrate 1 to the glass film 3. The intensity of the laser light 5 incident on the glass film 3 functioning as an optical element is made to have an intensity distribution spatially modulated by a modulation region 4 formed in the optical element of the glass film 3. The laser light 5 converted into an uneven intensity distribution in a plane parallel to the surface of the substrate 1 is emitted from the glass film 3 and enters the amorphous silicon film 2. The amorphous silicon film 2 receives energy from the laser beam 5 and generates heat to generate a temperature distribution inside the film. This temperature distribution is shown as a change in density in FIG. 2A, and is not uniform in a plane parallel to the surface of the substrate 1 corresponding to the intensity distribution of the laser beam. Therefore, solidification starts gradually in the silicon film 2 from a low temperature region, and crystals grow in a direction parallel to the surface of the substrate 1 to obtain large crystal grains. FIG.
(A) shows two modulation regions 4, and the density of crystal growth from the silicon film 2 immediately above these modulation regions 4 in a direction parallel to the surface of the substrate 1 is shown. The same effect as that described in the first embodiment can be obtained also by the method of manufacturing the thin film element according to the present embodiment shown in FIG.

FIG. 2B shows a modification of the configuration of FIG. 2A. In order to form the modulation region 4 in the glass film 3 and function as an optical element, it is necessary to add various elements in order to modulate the optical properties in the film. Therefore, in FIG. 2B, the glass film 3 is not used as a barrier layer, and a barrier of a silicon oxide film or a chamber silicon film deposited between the glass film 3 and the silicon film 2 by a plasma CVD method or the like. A layer 6 is provided. The same effect as that described in the first embodiment can be obtained also by the method of manufacturing the thin film element according to the present embodiment shown in FIG.

Next, a method of manufacturing a thin film device according to a third embodiment of the present invention will be described with reference to FIGS. Components having the same functions and functions as those of the first embodiment described with reference to FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. 3 to 5 each show a partial cross section of the substrate cut in a direction perpendicular to the glass substrate surface, and show a specific thin-film element manufacturing process according to the present embodiment. First, in FIG. 3 (a), immersed in a solution of tetraethoxysilane dissolved in ethanol and stirred while adding an aqueous ammonia solution,
The Corning 1737 (trade name) glass substrate 1 is dipped and then pulled up, and the glass film 3 is applied to the surface of the substrate 1 by a so-called sol-gel method. The solution may contain metal ions using potassium nitrate, lead nitrate, or the like.
In this example, sodium is contained using sodium nitrate.

Next, in FIG. 3 (b), a titanium film is deposited to a thickness of about 0.5 μm by DC sputtering and patterned by a photolithography process to become a modulation region 4 for changing optical properties. Then, a mask 7 having a pattern in which an opening is formed is formed.

Next, as shown in FIG.
Was formed in a molten salt solution 12 mixed with zinc sulfate, potassium sulfate and thallium sulfate at 500 ° C., and an electric field was applied to replace sodium with thallium and potassium. The electric field at this time is generated by applying a DC voltage of 15 V from the DC power supply 9 by bringing the negative electrode 10 close to the back surface of the substrate 1 and the positive electrode 11 close to the surface side of the substrate 1. The voltage application time to both electrodes 10 and 11 is 8 hours.

This is a so-called ion exchange method, in which thallium / potassium is diffused into the glass film 3 from the opening of the mask 7 by an applied electric field and replaces sodium, so that the refractive index of the glass film 3 exposed at the opening is changed. Can be made larger than other regions. After the processing is completed, the mask 7 is removed in a dilute hydrochloric acid solution. Next, an amorphous silicon film 2 is deposited to a thickness of 50 nm by plasma CVD using silane / hydrogen gas as a raw material.
Heat treatment for one hour is performed to remove hydrogen contained in the amorphous silicon film 2.

Next, as shown in FIG. 4A, a XeCl excimer laser (oscillation wavelength 308 n
m, a pulse time of 30 ns), and irradiate a laser beam with an irradiation energy of 330 mJ / cm 2 to turn the amorphous silicon film 2 into polysilicon. Next, as shown in FIG. 4 (b), the plasma CV
A silicon oxide film having a thickness of about 120 n is formed on the substrate 1 by the method D.
m, and an aluminum film is deposited to a thickness of about 200 nm by DC sputtering. Next, the silicon oxide film and the aluminum film are patterned to form a gate insulating film 14 and a gate electrode 13 formed by laminating the silicon oxide film and the aluminum film in this order. Reference numeral 19 in FIG. 4B indicates a crystal grain boundary generated in the silicon film 2. As shown in this figure, according to the present embodiment, since the laser light intensity distribution can be easily given so as to match the element, the number of crystal grain boundaries 19 in the channel region of the element can be reduced. do it,
It is also possible to make the crystal grain boundaries 19 exist only outside the channel region, and it is possible to improve the yield of device manufacture.

Next, as shown in FIG. 5A, phosphorus (P) ions are implanted into the silicon film 2 using the gate electrode 13 as a mask to form a source region 15 and a drain region 16.
To form Next, as shown in FIG. 5B, an aluminum film is deposited to a thickness of about 200 nm by DC sputtering, and the source electrode 17 is formed by photolithography.
And a drain electrode 18 are formed. These source electrodes 1
7. When patterning the drain electrode 18, the alignment at the time of photolithography is performed using the alignment marks formed in the glass film 3 at the same time as the formation of the modulation region 4, which will be described in detail later. .

Next, a method of manufacturing a thin film device according to a fourth embodiment of the present invention will be described with reference to FIG. FIG.
Components having the same functions and functions as those of the third embodiment described with reference to FIGS. 5 to 5 are denoted by the same reference numerals, and description thereof will be omitted. FIG. 6 shows a partial cross section of the substrate cut in a direction perpendicular to the glass substrate surface, and shows a specific thin film element manufacturing process according to the present embodiment. First, in FIG.
A glass film 3 of a silicon oxide film having a thickness of about 300 nm is deposited on a 37 glass substrate 1 by a plasma CVD method.

Next, in FIG. 6 (b), a photoresist is applied to the entire surface and then patterned by a photolithography process to have a pattern in which an opening is formed at a position to be a modulation region 4 for changing optical properties. Mask 7
To form

Next, as shown in FIG.
, Boron (B) ions 20 are implanted at an acceleration voltage of 80 keV and at a dose of 1 × 10 17 / cm 2.
Next, the substrate 1 is heated at 450 ° C. for 1 hour in a nitrogen atmosphere to stabilize boron implanted into the glass film 3 from the opening of the mask 7 to increase the refractive index of the region. In the above example, boron was used, but as a material that can be used in this ion implantation method, for example, Al, In, B
i, Cu, Au, Ag, N and the like. The subsequent steps for forming the element are the same as those in the third embodiment, and a description thereof will be omitted.

The present embodiment is characterized in that an optical element whose refractive index is modulated using a semiconductor process can be formed without using a molten salt which is difficult to handle as in the third embodiment. ing. Further, since ions to be implanted can be freely selected, a desired refractive index can be easily obtained.

Next, a method of manufacturing a thin film device according to a fifth embodiment of the present invention will be described with reference to FIGS. Components having the same functions and functions as those described in the first to fourth embodiments are denoted by the same reference numerals, and description thereof is omitted. 7A to 9A show a partial plan view of the substrate 1 as viewed from the element formation side, and FIGS. 7B to 9B show A- 2 shows a partial cross section of the substrate cut along a line A in a direction perpendicular to the surface of the substrate 1.

As shown in FIG. 7A, an alignment mark 21 is formed at a predetermined position together with the modulation area 4 on the glass film 3 on the substrate 1. The alignment mark 21 is used for positioning the substrate and the mask in a photolithography process. Since the alignment mark 21 is formed simultaneously with the formation of the modulation region 4 of the glass film 3, it has a different refractive index from the peripheral region. Therefore, the presence of the alignment mark 21 can be confirmed by optical observation from the silicon film 2 side or the glass substrate 1 side. Therefore, based on the position of the alignment mark 21, the relative position of each modulation region 4 and the region 22 crystallized by expanding the crystal grain size can be positioned. The region 23 is a region where the modulation region 4 is not arranged, and is a region of a polysilicon film having a smaller crystal grain size than the region 22.

In the manufacturing process of the thin film element, the alignment mark 21 according to the present embodiment works extremely effectively in a photolithography process in which the formation position of each component and the position of the mask need to be accurately aligned. It is possible to improve the throughput in element manufacturing.

Now, a method of manufacturing the thin film device according to the present embodiment will be described with reference to FIGS. The Corning 1737 glass substrate 1 is immersed in a solution obtained by dissolving tetraethoxysilane in ethanol and then stirred while adding an aqueous ammonia solution in the same manner as in the process described in the third embodiment. Then, the glass film 3 is adhered to the surface of the substrate 1 by a sol-gel method. Thereafter, a mask having a predetermined pattern is formed on the surface of the glass film 3 so as to form the alignment mark 21 together with the modulation region 4, and the modulation region 4 and the alignment mark 21 whose refractive index is changed by the ion exchange method are formed. As the mark shape of the alignment mark 21 to be formed, not only a cross pattern as shown in FIG. 7 but also a circular pattern, a square pattern, or various patterns obtained by combining them.

Next, as shown in FIG. 8, silane, hydrogen,
The thickness is about 2 by plasma CVD method using laughing gas as raw material.
A 00 nm silicon oxide film is formed. This silicon oxide film functions as the barrier layer 6. Next, silane and hydrogen gas are used as raw materials by plasma CVD to about 50 nm.
Is deposited, and heat treatment is performed at 450 ° C. for 1 hour in an electric furnace to remove hydrogen contained in the amorphous silicon film 2.

Next, as shown in FIG. 9, a laser beam is irradiated from the back surface of the substrate 1 with a XeCl excimer laser (oscillation wavelength: 308 nm, pulse time: 30 ns) and irradiation energy of 330 mJ / cm 2, and the amorphous silicon film 2 is irradiated. Polysilicon.

Since the region 22 having a large crystal grain size is arranged in alignment with the modulation region 4, in order to match the channel region of the thin film transistor with the region 22 having a large crystal grain size, the channel formation region must also be aligned with the modulation region 4. It is necessary to arrange at the position corresponding to. However, since the difference in optical properties between the region 22 where the modulation region 4 exists and the region 23 where the modulation region 4 does not exist is small, it is difficult to optically detect and align the position of the region 22 having a large crystal grain size. It is. Therefore, by using the alignment mark 21 of the present embodiment, the channel region of the thin film transistor and the modulation region 4 can be easily matched. For example, after a photoresist is applied to the entire surface of the substrate, the region 22 having a large crystal grain boundary in the polysilicon film 2 is accurately formed in the channel formation region of the thin film element by a photolithography process using the alignment mark 21 according to the present embodiment. It can be patterned. In this patterning, an alignment mark may be formed on the polysilicon film 2. In that case, the subsequent photolithography is the same as a normal alignment operation. In addition,
Subsequent steps of forming the thin film transistor are the same as in the third embodiment, and a description thereof will be omitted.

The present invention is not limited to the above embodiment, but can be variously modified. For example, in the above-described embodiment, a structure in which the glass film 3 and the silicon film 2 are directly in contact with each other and a structure in which a barrier layer such as a silicon oxide film or a silicon nitride film is interposed between the glass film 3 and the silicon film 2. Either one is shown for each embodiment, but in each embodiment, a thin film element can be manufactured with both structures.

[0039]

As described above, according to the present invention, the intensity of the laser beam can be modulated so as to match the element without irrespective of mechanical accuracy, and irradiation can be performed. By reducing the crystal grain boundaries from the channel region of the device, a thin film device having excellent device characteristics can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a method for manufacturing a thin-film element according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a method for manufacturing a thin-film element according to a second embodiment of the present invention.

FIG. 3 is a diagram illustrating a method for manufacturing a thin-film device according to a third embodiment of the present invention.

FIG. 4 is a diagram illustrating a method for manufacturing a thin film device according to a third embodiment of the present invention.

FIG. 5 is a diagram illustrating a method for manufacturing a thin film device according to a third embodiment of the present invention.

FIG. 6 is a diagram illustrating a method for manufacturing a thin film device according to a fourth embodiment of the present invention.

FIG. 7 is a diagram illustrating a method of manufacturing a thin-film element according to a fifth embodiment of the present invention.

FIG. 8 is a diagram illustrating a method for manufacturing a thin-film element according to a fifth embodiment of the present invention.

FIG. 9 is a view illustrating a method of manufacturing a thin-film element according to a fifth embodiment of the present invention.

FIG. 10 is a diagram illustrating a conventional method of manufacturing a thin film element.

[Explanation of symbols]

 Reference Signs List 1 substrate 2 silicon film 3 glass film 4 modulation region 5 laser beam 6 barrier layer 7 mask 9 DC power supply 10, 11 electrode 12 molten salt solution 13 gate electrode 14 gate insulating film 15 source region 16 drain region 17 source electrode 18 drain electrode 19 Crystal grain boundary 20 ion 21 alignment mark

Continued on the front page F term (reference) 2H092 JA24 KA04 KA05 MA05 MA08 MA09 MA29 MA30 NA27 NA29 PA01 5F052 AA02 BB07 CA04 DA02 DB03 EA02 EA12 JA01 5F110 AA16 AA26 BB01 CC02 DD02 DD13 DD14 DD17 DD25 EE03 FF30 FF23 GG45 GG58 HJ01 HJ13 PP04 PP23 PP35 QQ11

Claims (6)

[Claims] 1. A method for manufacturing a thin film element formed on an insulating substrate, comprising: forming an amorphous silicon film on the insulating substrate; and forming a glass film on the amorphous silicon film. And a step of changing the optical property of the glass film at least in a direction parallel to the surface of the insulating substrate; and making light incident on the glass film and modulating the intensity distribution of the light with the glass film. And causing the amorphous silicon film to enter the amorphous silicon film to crystallize the amorphous silicon film. 2. A method of manufacturing a thin film element formed on an insulating substrate, comprising: forming a glass film on the insulating substrate; and adjusting the optical properties of the glass film at least on the surface of the insulating substrate. Changing the light in a direction parallel to the direction; forming an amorphous silicon film on the glass film; irradiating light to the glass film, and modulating the intensity distribution of the light by the glass film to form the amorphous silicon film. Making the amorphous silicon film crystallize by entering the film into the crystalline silicon film. 3. The method for manufacturing a thin film device according to claim 1, wherein an ion exchange method is used in the step of changing the optical properties of the glass film. 4. The method for manufacturing a thin film element according to claim 1, wherein an ion implantation method is used in the step of changing optical properties of the glass film. 5. The method for manufacturing a thin film element according to claim 1, wherein the step of changing an optical property of the glass film includes simultaneously forming an alignment mark for positioning in the glass film. A method for manufacturing a thin film element. 6. The method for manufacturing a thin film device according to claim 1, wherein the glass film is formed so as to include a silicon-based oxide.