JP2003282436A - Heat-treatment apparatus for substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat-treatment apparatus that can sufficiently and uniformly heat-treat a silicon film on a substrate, and has an improved apparatus life time. <P>SOLUTION: In a heat-treatment chamber 65, a flash heating means 80 and a preheating means 90 are provided above and below while a glass substrate W is held between them. The preheating means 90 is used of preheating the glass substrate W to 200 to 400°C. The preheated glass substrate W is heat- treated by the flash irradiation of a xenon flash lamp 81. By the flash irradiation, the amorphous silicon film on the glass substrate W is uniformly heated, and thus polycrystallinity is achieved. The xenon flash lamp 81 is arranged displaced from a virtual line L1 of the flash irradiation so that the preheating means 90 is not exposed by the flash irradiation. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate heat treatment apparatus for improving the characteristics of a material by irradiating it with light,
It is particularly suitable for use in polycrystallizing an amorphous silicon film at the time of manufacturing a semiconductor substrate and a thin film transistor (TFT) for a liquid crystal display device.

[0002]

2. Description of the Related Art For high resolution displays, a polycrystalline silicon thin film transistor (TF) is used as a switching element.
A small, high-definition active matrisk type liquid crystal display (LCD) panel using T) has been developed. When a polycrystalline silicon TFT is used for an active element of an LCD, a pixel array section and a drive array section can be formed on the same transparent insulating substrate in the same process, which has an advantage that steps such as wire bonding and drive IC mounting can be reduced. is there.

A polycrystalline silicon TFT is a semiconductor thin film (thickness of several tens to several hundreds nm) formed on a substrate having an insulating surface.
This is a technique for forming a thin film transistor (TFT) by using (about). Especially when a TFT is used as a switching element of an LCD, the drive circuit requires a drive frequency of several hundred kHz or more. Therefore, a TFT using a polycrystalline silicon film (polysilicon film) as an active layer is used to form the drive circuit. Needed.

Hitherto, high temperature annealing has been required to form a highly crystalline polysilicon film. Such a polysilicon film is generally called high temperature polysilicon. 10 to form a high temperature polysilicon film
A substrate having a high heat resistance capable of withstanding a process temperature close to 00 ° C. is required, and for that reason, a quartz substrate (or a silicon substrate in some cases) is currently used.

However, the unit cost of the quartz substrate is high, and there is a problem in that the manufacturing cost and the product cost increase. Therefore, recently, a low temperature polysilicon film formed on an inexpensive glass substrate has received attention. This low-temperature technology reduces the process temperature to 600 ° C or lower. In this temperature range, a hard glass substrate with a large area can be used at a low cost, so a large LC circuit integrated with a drive circuit can be used.
It is possible to realize a D or a lower cost compact LCD.

However, it is not technically easy to manufacture a high-performance polysilicon TFT in this temperature range, and an amorphous silicon thin film or a polysilicon thin film is made amorphous by ion-implanting silicon. There is a heat treatment method of irradiating with and polycrystallizing. For example, a SiO ₂ (silicon oxide) film is formed as an insulating film serving as a base film on a glass substrate, and an amorphous amorphous silicon film is formed on the SiO ₂ film by low pressure CVD (Chemical Vapor Deposition). Then, a polysilicon film is formed by crystallizing the amorphous silicon film by a heat treatment process such as a laser annealing process, a solid phase growth process, and a lamp annealing process.

Then, the polysilicon film is doped with a predetermined amount of a donor and an acceptor to form a channel forming region, a drain region and the like. Furthermore, a gate insulating film, a gate electrode, a source electrode, a drain electrode,
A thin film transistor is formed by forming an interlayer insulating film or the like, and a semiconductor device including the thin film transistor is manufactured.

Further, in the case of the structure in which the crystallized polysilicon film is doped with impurities such as phosphorus and boron,
The light irradiation process is performed for the purpose of activating the impurities implanted in the doping process and modifying the interface of the film.

[0009]

However, the conventional example having such a structure has the following problems. In the above-mentioned conventional light irradiation heat treatment method, the light source and the large substrate are moved relative to each other in response to the increase in the size of the liquid crystal glass TFT substrate, and the large substrate passes through the light irradiation area by the light source, so that the light irradiation processing of the entire surface of the substrate is performed. Japanese Patent Application Laid-Open No. 200
It is proposed as Japanese Patent Publication No. 1-110738. As a result, there is an advantage that large substrates can be continuously processed. Further, there is disclosed a heat treatment apparatus in which a substrate is preheated by a preheating unit before the substrate is heated by a light source. A light source such as a lamp is used as the preheating means used in the heat treatment apparatus described above. On the other hand, it is possible to raise the temperature of only the silicon film in a short time by irradiating the surface of the substrate with flash light using a flash lamp or the like as the light source.

However, in the case of adopting a structure in which the temperature of the surface of the substrate is raised by using flash light, the flash light or radiant heat transmitted through the substrate results in burning or deterioration of the filament of the lamp of the preheating means. Will result.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a substrate heat treatment apparatus capable of operating stably.

[0012]

In order to achieve the above object, the present invention is a heat treatment apparatus for heat treating a substrate by irradiating the substrate with light, which is arranged on the back surface side of the substrate. Preheating means for preheating the substrate in a light irradiation region generated by light irradiation through a condenser, and a substrate arranged on the front surface side of the substrate to raise the substrate to a preset preheating temperature. After heating, a flash for irradiating the preheated substrate to the processing temperature by irradiating the same position on the surface of the substrate as the light irradiation region by the preheating means with a flash through a condenser. A heating means, wherein the preheating means and the flash heating means are arranged so as to be inclined in the same direction with respect to a vertical line in the light irradiation region. It is a device.

The operation of the present invention is as follows. In the substrate heat treatment apparatus according to the first aspect of the present invention, the substrate is heated in the preliminary heating step and heated to the processing temperature by flash light irradiation. This flash does not require much energy because the glass substrate has been heated in advance.
Further, the preheating means and the flash heating means are arranged so as to be inclined in the same direction with respect to the perpendicular to the light irradiation area on the substrate. As a result, most of the flash light is prevented from reaching the preheating means by the flash heating means. Therefore,
The preheating means is not deteriorated by the flash light.

According to a second aspect of the present invention, in a heat treatment apparatus for heat-treating a substrate by irradiating the substrate with light, the substrate is arranged on the back surface side of the substrate, and the substrate is irradiated with light through a condenser. Preheating means for preheating in the generated light irradiation area, and the light arranged by the preheating means arranged on the front surface side of the substrate and heated to a preheating temperature set in advance by the preheating means on the surface of the substrate. Flash heating means for raising the temperature of the preheated substrate to a processing temperature by irradiating the same position as the irradiation area with flash light through a condenser, and the flash heating means and the light irradiation area. In the heat treatment apparatus for a substrate, the preliminary heating means is arranged at a position deviating from a virtual line connecting the two.

According to the invention of claim 2, the preheating means is arranged at a position deviating from the imaginary line connecting the flash heating means and the light irradiation area. As a result, most of the flash light is prevented from reaching the preheating means by the flash heating means. Therefore, the preheating means is not deteriorated by the flash light.

According to a third aspect of the present invention, in the heat treatment apparatus for a substrate according to the first and second aspects, the light irradiation area generated by the preheating means and the flash heating means, and the inside of the light irradiation area are provided. It is characterized in that the substrate arranged on the substrate moves relative to the substrate.

According to the third aspect of the present invention, the entire surface of the substrate is continuously processed, and the preheating means and the flash heating means do not have to be arranged so as to cover the entire surface of the substrate.

According to a fourth aspect of the present invention, in the heat treatment apparatus for a substrate according to any of the first to third aspects, light is further emitted to the front surface side of the substrate on an imaginary line connecting the preheating means and the light irradiation region. A first detector for detecting and a second detector for detecting light on the back surface side of the substrate on an imaginary line connecting the flash heating means and the light irradiation region are provided.

According to the invention of claim 4, the first and second detectors detect the light transmitted through the substrate. As a result, for example, it is possible to detect a defect such as no irradiation of light from the preheating means and the flash heating means.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. <First Embodiment> FIG. 1 is a sectional view of a heat treatment apparatus according to an embodiment of the present invention, and FIG. 2 is a schematic plan view thereof.
And FIG. 3 is an enlarged view of a main part inside the heat treatment apparatus.

This heat treatment apparatus comprises an upper plate 61, a bottom plate 62, and a pair of side plates 63, 64, and a glass substrate W having an amorphous silicon film formed thereon is housed therein for heat treatment. A heat treatment chamber 65 is provided. Each plate 61, 62, 63, 6 forming the heat treatment chamber 65
4 is made of, for example, a material such as stainless steel, and has its surface polished so as to prevent deformation due to radiant heat during a heat treatment process using flash light described later. Further, in the space forming the heat treatment chamber 65, a transfer means 70 for supporting and transferring the glass substrate W described later from its lower surface is arranged.

The conveying means 70 in the heat treatment chamber 65 has a plurality of conveying rollers 71 arranged from the vicinity of the opening 66 toward the inside. The transport roller 71 is driven by a drive source (not shown) disposed outside the side plate forming the heat treatment chamber 65 to rotate forward and backward, and transports the glass substrate W above it.

Further, the side plate 64 constituting the heat treatment chamber 65 is formed with an opening 66 for loading and unloading the glass substrate W. The opening 66 can be opened and closed by a gate valve 68 that rotates about a shaft 67. The glass substrate W has the opening 66 opened,
It is carried into the heat treatment chamber 65 by a transfer robot (not shown).

Above the transfer means 70 in the heat treatment chamber 65,
A flash heating means 80 is arranged. In the flash heating means 80, one rod-shaped xenon flash lamp 81 is arranged in parallel with the conveying means 70 as shown in an enlarged view in FIG. Further, a reflector 82 is arranged above the xenon flash lamp 81, and a lens 83 as a condenser is arranged below the xenon flash lamp 81.

The xenon flash lamp 81 has a glass tube in which a xenon gas is sealed and an anode and a cathode connected to a condenser are provided at both ends of the glass tube, and the glass tube is wound around the outer circumference of the glass tube. And a trigger electrode. Since xenon gas is an electrical insulator, electricity does not flow in the glass tube under normal conditions. However, when a high voltage is applied to the trigger electrode to break the insulation, electricity stored in the capacitor flows into the glass tube, and the Joule heat at that time heats the xenon gas to emit light. This xenon flash lamp 8
In No. 1, since the electrostatic energy stored in advance is converted into an extremely short light pulse of 0.1 millisecond to 10 millisecond, it is possible to irradiate extremely strong light compared with the light source for continuous lighting. Have.

The lens 83 is, as shown in the side view of FIG. 4, a polarizing lens 831 made of quartz for uniforming the peripheral exposure.
A glass plate 832 made of quartz glass or diffusion glass is arranged on the glass substrate W side of the polarizing lens 831.

The flash light from the xenon flash lamp 81 and the reflected light from the reflector 82 are condensed by the lens 83, and a strip-shaped light irradiation area M1 is generated on the surface of the glass substrate W located on the transport means 70. The light irradiation region M1 has a spread in the transport direction F of the glass substrate W around the point P1 where the virtual line L1 connecting the xenon flash lamp 81 and the lens 83 intersects on the surface of the glass substrate W, and the width direction of the glass substrate W. It has a strip shape with the same length as (direction perpendicular to the transport direction). In addition, the end of the glass substrate W along the transport direction F collects light from the polarizing lens 831 to correct the thermal gradient at the end of the glass substrate W.

An imaginary line L1 connecting the xenon flash lamp 81 and the point P1 of the light irradiation area M1 has an angle α with respect to a perpendicular line L2 on the surface of the glass substrate W, which is opposite to the carrying direction F of the glass substrate W. The xenon flash lamp 81 is arranged so as to be inclined. This angle α is preferably set to 45 degrees in the range of 0 <α <90 degrees.

Below the conveying means 70 in the heat treatment chamber 65,
A preheating means 90 for preheating the glass substrate W is arranged. In the preheating means 90, one rod-shaped halogen lamp 91 is arranged in parallel with the conveying means 70. Further, a reflector 92 is provided near the halogen lamp 91,
A lens 93 having the same configuration as the lens 83 as a condenser is arranged above.

In the halogen lamp 81, lighting and reflected light from the reflector 82 are condensed by the lens 93, and a band-shaped light irradiation area M2 is formed on the back surface of the glass substrate W located on the conveying means 70. This light irradiation area M2
Is a virtual line L3 connecting the halogen lamp 91 and the lens 93.
Are intersected with each other on the surface of the glass substrate W, that is, the size is set to have the same size as the light irradiation region M1 on the surface side of the glass substrate W with the point P1 as the center. As a result, the same area of the glass substrate W is heated by irradiation with light from the front and back surfaces.

An imaginary line L3 connecting the halogen lamp 91 and the point P1 of the light irradiation area M2 has an angle α with respect to the perpendicular line L2 of the surface of the glass substrate W, which is opposite to the conveying direction F of the glass substrate W, and the halogen. The lamp 81 is arranged to be inclined. This angle α is preferably set to 45 degrees in the range of 0 <α <90 degrees. That is, it is tilted in the same direction as the xenon flash lamp 80 at the same tilt angle.

Further, on the downstream side of the transport direction F of the glass substrate W, a first detector 95 is arranged above the front surface of the glass substrate W, and a second detector 85 is arranged below the rear surface of the glass substrate W.
The first detection 95 includes the halogen lamp 91 and the light irradiation area M2.
It is composed of a lens 96 for condensing the light transmitted to the front surface side of the glass substrate W and a light receiver 97 on a virtual line L3 connecting the two.
The second detector 85 is composed of a lens 86 for condensing light that is transmitted to the back surface side of the glass substrate W on a virtual line L1 connecting the xenon flash lamp 81 and the light irradiation area M1 and a light receiver 87. When light is detected by these light receivers 87 and 97, the signal is input to the control unit 100 described later.

At the loading / unloading position of the glass substrate W shown in FIG. 1, the glass substrate W loaded through the opening 66 is placed on the transport roller 71 by using a transport robot (not shown), or on the transport roller 71. This is a state for carrying out the glass substrate W placed on the opening 66 from the opening 66.

In the heat treatment state of the glass substrate W from the state shown in FIG. 1, since the glass substrate W is subjected to the heat treatment, the glass substrate W is conveyed into the heat treatment chamber 65 by the rotation of the conveying roller 71. In this carrying process, the front and back surfaces of the glass substrate W are heated by the light irradiation areas M1 and M2 set between the carrying rollers 71, and the entire surface is irradiated with light while being sequentially moved. When the entire surface of the glass substrate W reaches the downstream side in the transport direction F, the transport roller 71 reverses to return the glass substrate W to the loading / unloading position.

An introduction path 75 is formed in the side plate 63 on the opposite side of the opening 66 in the heat treatment chamber 65. The introduction path 75 is for introducing air when the atmosphere is released, which will be described later. Note that nitrogen gas or the like may be introduced instead of introducing air.

On the other hand, a discharge path 76 is formed in the bottom plate 62 in the heat treatment chamber 65. This discharge path 76 is
It is connected to a pressure reducing mechanism such as a vacuum pump via an opening / closing valve 77. The discharge passage 76, the opening / closing valve 77, and the depressurizing mechanism (not shown) constitute the depressurizing means according to the present invention.

The control unit 100 has a flash heating means 80.
And the heat treatment process by the preheating means 90, the first detector 95
The lamp state is detected by the second detector 85, the transfer operation of the glass substrate W that controls the transfer unit 70 and the gate valve 68, and the atmosphere in the heat treatment chamber 65 is controlled by the decompression unit.

Next, the heat treatment operation of the glass substrate W by the heat treatment apparatus according to the present invention will be described. FIG. 5 is a flow chart showing the heat treatment operation of the glass substrate W by the heat treatment apparatus according to the present invention, and FIG. 6 shows a graph showing the transition of the temperature of the glass substrate W and the glass substrate transfer timing at that time.

First, as a substrate, as shown in FIG.
A glass plate W1 having a thickness of 5 to 1.1 mm (typically 0.7 mm) is prepared. The glass plate W1 is generally used for an LCD display device. When the glass plate W1 as described above is prepared, the amorphous silicon film W is added to the glass plate W1.
2 is deposited to form a glass substrate W.

In this heat treatment apparatus, with the gate valve 68 open, the glass substrate W is loaded through the opening 66 by the transport robot (not shown) and placed on the transport roller 71 at the load / unload position. . When the loading of the glass substrate W is completed, the opening 66 is closed by the gate valve 68 (step S1). Then, the transport roller 71 starts rotating at timing T11 in FIG. 6 to move the glass substrate W in the transport direction F.

The preheating means 90 is a halogen lamp 9.
Lighting is started at the same time as the operation of the transport roller 71, or when the detection unit (not shown) detects that the first processed portion of the glass substrate W has reached the light irradiation region M2. Therefore, the back surface of the glass substrate W is preheated, and the temperature of the glass substrate W is sequentially increased as shown in FIG. 6 (step S2).

In parallel with the lighting of the preheating means 90,
The pressure inside the heat treatment chamber 65 is reduced (step S3). That is, the on-off valve 77 is opened and the introduction path 75 is connected to a decompression mechanism (not shown), so that the inside of the heat treatment chamber 65 is exhausted and decompressed. At this time, in order to effectively bring out various effects to be described later, the inside of the heat treatment chamber 65 is 1/10 atm to 1 / atm.
It is preferable to reduce the pressure to 1000 atm.

When the glass substrate W is transported and the first processed portion on the surface overlaps the light irradiation area M2, the control unit 1
00 stops driving of the conveyance roller 71.

In this state, the glass substrate W is continuously heated by the preheating means 90. Then, when the temperature of the glass substrate W rises, a surface temperature of the glass substrate W, that is, whether or not the amorphous silicon film W1 has reached the preheating temperature T1 is constantly monitored by a temperature sensor (not shown) (step S4). .

The preheating temperature T1 is 20 degrees Celsius.
The temperature is from 0 to 400 degrees Celsius. Glass substrate W
Is heated to the preheating temperature T1 of this degree,
The amorphous silicon film W1 is never polycrystallized. Further, the glass plate W1 does not warp or warp.

Immediately after the surface temperature of the glass substrate W reaches the preheating temperature T1 shown in FIG. 6, the xenon flash lamp 81 is turned on to perform flash heating (step S5). The lighting time of the xenon flash lamp 81 in this flash heating step is about 0.1 millisecond to 10 millisecond, and the light irradiation region is in the energy range of 10 to 30 J / cm ^{2 in} the wavelength range from visible light to infrared light. Irradiate M1. As described above, in the xenon flash lamp 81, since the electrostatic energy stored in advance is converted into such an extremely short light pulse, an extremely strong flash light is emitted.

In this state, the surface temperature of the glass substrate W becomes the temperature T2 shown in FIG. This temperature T2 is a temperature required for processing the glass substrate W at about 500 degrees Celsius to about 600 degrees Celsius. When the surface of the glass substrate W is heated to such a processing temperature T2, the amorphous silicon film W2 is crystallized to form a polysilicon film. In this state, the amorphous silicon film W2 in the light irradiation region M1 irradiated with light on the glass substrate W is melted by light energy and recrystallized to be a polysilicon film.

The light irradiation energy at this time is appropriately adjusted depending on the film thickness of the amorphous silicon film W2 to be irradiated, but since the temperature is raised in advance by the preheating step,
It is adjusted within the above range.

At this time, the surface temperature of the glass substrate W is 0.
Since the temperature is raised to the processing temperature T2 in an extremely short time of about 1 millisecond to 10 milliseconds, the recrystallization of the amorphous silicon film W2 on the glass substrate W is completed in a short time. Therefore, it is possible to reduce the processing time and prevent the temperature of the glass plate W1 from rising.

Before the xenon flash lamp 81 is turned on to heat the glass substrate W, the preheating means 90 is used.
Is used to heat the surface temperature of the glass substrate W to a preheating temperature T1 of about 200 to 400 degrees Celsius, the glass substrate W is heated to about 500 to 600 degrees Celsius by the xenon flash lamp 81. It is possible to quickly raise the temperature to the processing temperature T2.

In this flash heating step, each of the plates 61, 62, 63 and 64 forming the heat treatment chamber 65 receives a light ray which is not absorbed by the amorphous silicon film W2. However, since each plate 61, 62, 63, 64 is made of aluminum whose surface is polished, each plate 6
No thermal deformation occurs in 1, 62, 63, 64.

The flash heating step described above is performed under reduced pressure. Therefore, as in the conventional case, the heat treatment chamber 6
The gas does not react within 5 to diffuse the particles or move the glass substrate W.

Similarly, by reducing the pressure in the heat treatment chamber 65, it is possible to uniformly heat the entire surface of the glass substrate W in the preheating process and the flash heating process without generating convection in the heat treatment chamber 65. Become.

Similarly, since the xenon flash lamp 81 and the halogen lamp 91 are arranged so as to be inclined at the angle α, even if the respective irradiation lights travel along the virtual lines L1 and L3, they pass through the glass substrate W. They are not exposed to each other's direct light. As a result, it is possible to prevent the components such as the filaments forming the respective lamps from being deteriorated by the irradiation light or the radiant heat. In particular, since the halogen lamp 91 is not directly exposed to the intense flash of the xenon flash lamp 81, it can be used for a longer life.

Furthermore, by reducing the pressure in the heat treatment chamber 64, it is possible to remove oxygen and organic substances from the heat treatment chamber 65. Therefore, it is possible to prevent the life of the heat treatment apparatus from being shortened due to the oxidation of the material forming the heat treatment chamber 65 and the blackening of the organic matter.

When the heat treatment of the first heat treatment site is completed,
The carrying roller 71 is driven again from the timing T12, and step carrying S6 is carried in which the second heat treatment site is carried. The carrying distance of the step carrying S6 is set to a length in the carrying direction F equivalent to that of the light irradiation area M1 or a slightly shorter distance. By doing so, the entire surface of the glass substrate W can be processed by sequentially moving the heat treatment area in the same range as the light irradiation area M1 without any gap.

Then, unless the rear end of the glass substrate W passes through the light irradiation region M1, the process returns to step S4 in step S7, and heat treatment from preheating by light irradiation heating to flash heating is performed in the same manner as the first heat treatment site. Is done. The preheating by the preheating means 90 is continued during the step conveyance S6, and when the preheating temperature T1 is reached, the flash heating S5 is performed. By repeating this operation, the entire surface of the glass substrate W is heat-treated.

During the heat treatment process of steps S4 to S7 of the glass substrate W, the first detector 95 and the second detector 85 are provided.
Always detects the irradiation light. Then, each transmits the detection signals from the light receiver 97 and the light receiver 87 to the control unit 100. By doing so, the control unit 100 monitors whether the xenon flash lamp 81 and the halogen lamp 91 are lit at a timing according to a preset program. When the signals from the light receivers 87 and 97 are not received at the timings when the respective lamps are turned on, the control unit 100 stops the heat treatment apparatus or operates the abnormality operation panel in order to prevent processing defects of the glass substrate W. It can be configured such as to be displayed on. According to this configuration, since the lamp abnormality is confirmed during the light irradiation heat treatment,
It is possible to respond to abnormalities more quickly.

When the detection of light by the first detector 95 and the second detector 85 is performed during the light heating process,
Since the light transmitted through the glass substrate W is detected, the light receiver 8
Since the levels of the signals from 7 and 97 become small, it is necessary to set the set level in the determination flow by the control unit 100 to a value that is obtained in advance by experiments or the like.

When the heat treatment process is completed by detecting that the rear end of the glass substrate W has passed through the light irradiation region M1,
By closing the on-off valve 77 and introducing air from the introduction path 76, the heat treatment chamber 65 is opened to the atmosphere (step S8). Then, the halogen lamp 91 of the preheating means 90 is turned off (step S9). In addition, the control unit 10
In timing 0, the transport roller 71 is reversed at timing T110 to transport the glass substrate W to the carry-out position and stop.

The flash heating is performed immediately after the surface temperature of the glass substrate W reaches the preheating temperature T1 for the following reason. In the heat treatment apparatus according to the present invention, by performing flash heating immediately after the surface temperature of the glass substrate W reaches the preheating temperature T1, the flash heating becomes higher than the preheating temperature T1. Prevent it from being executed at some point.

At the same time, after the heating process of the entire surface of the glass substrate W is completed, the inside of the heat treatment chamber 65 is exposed to the atmosphere to lower the temperature inside the heat treatment chamber 65.

When the atmospheric release of the heat treatment chamber 65 is completed, the opening 66 closed by the gate valve 68 is released. Then, the glass substrate W placed on the carrying roller 71 is carried out by a carrying robot (not shown) (step S8).

As described above, a good quality polycrystalline silicon film is obtained by the heat treatment according to the present invention. As a result,
A TFT having excellent characteristics can be obtained. Further, the device can be downsized and the life of parts can be improved. As a result, for example, a liquid crystal display (LCD) panel using TFT can be manufactured at low cost.

Next, the maintenance process in this heat treatment apparatus will be described. The flash heating means 80 and the preheating means 90 have a first detector 95 and a second detector 85 arranged in the respective light irradiation directions. With the glass substrate W not loaded, the xenon flash lamp 8
1 and the halogen lamp 91 are individually turned on by an operation unit (not shown), and the control unit 100 controls the lighting. The signals detected by the light receivers 87 and 97 for the light irradiation by this lighting are input to the control unit 100. And ON / OF of this signal
The lighting state is judged by F or strength.

That is, the xenon flash lamp 81
If no light is emitted due to an abnormality, there is no light received by the photodetector 87 through the lens 86, so no signal is output from the second detector 85. As a result, the operator is prompted to perform maintenance by displaying the abnormality of the xenon flash lamp 81 on the operation unit.

By doing so, the lighting failure of the xenon flash lamp 81 can be confirmed in the heat treatment chamber 65 which is hermetically sealed. Further, even when the lighting state is weak, the light can be detected by condensing the light at the site where the light irradiation intensity is the strongest. Further, even if there is reflected light in the heat treatment chamber 65, it has little influence on the detected light that is collected, and can be detected more accurately.

Also, in the case of the first detector 95 of the preheating means 90 corresponding to the halogen lamp 91, similarly, the lighting state of the halogen lamp 91 can be accurately detected.

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 8 is an enlarged view of a main part inside the heat treatment apparatus. That is, the flash heating means 80 and the preheating means 90 are not arranged so as to be inclined in the same direction with respect to the perpendicular line L2 in the light irradiation region M1, but the preheating means is located at a position deviated from the imaginary line L1 of the flash heating means 90. By arranging 90, you may comprise so that it may not be directly exposed to mutually irradiated light. In the case of this configuration, the second detector 95 can be arranged close to the flash heating means 80 on the front surface side of the glass substrate W, so that the arrangement position is opposite to the direction in which the irradiation light from the flash heating means 80 travels. ,
The influence of light from the flash heating means 80 on the second detector 95 can be reduced. Similarly, on the back surface side of the glass substrate W, the first detector 85 can be arranged at a portion where the influence of the preheating means 90 is small.

The present invention is not limited to the above-described embodiments, but can be implemented in other forms as follows.

(1) In the above embodiment, the example of polycrystallizing the amorphous silicon film has been described, but the above-mentioned amorphous silicon film is formed as the glass substrate on which the silicon film is formed. In addition to the glass substrate, a glass substrate on which a silicon nitride film is formed or a glass substrate on which various silicon films are formed, such as a glass substrate on which a polycrystalline silicon film is formed, The heat treatment method can be carried out. For example, a polycrystalline silicon film formed by the CVD method is ion-implanted with silicon to form an amorphous silicon film, and a silicon oxide film serving as an antireflection film is further formed thereon. In this state, the entire surface of the amorphous silicon film is irradiated with light, and the heat treatment according to the present invention is performed to form a polycrystalline silicon film in which the amorphous silicon film is polycrystallized.

(2) Further, the base SiO _{2 is formed} on the glass substrate.
A TFT substrate having a film, a polysilicon film obtained by crystallizing amorphous silicon, and having a structure in which the polysilicon film is doped with impurities such as phosphorus and boron may be heat-treated according to the present invention. The purpose of performing such a light irradiation treatment is mainly to activate the impurities implanted in the doping process and to modify the film. In this process, it is possible to perform a uniform process.

Besides, it is possible to make various design changes within the scope of the technical matters described in the claims.

[0074]

According to the present invention, a large-sized substrate is preheated by light irradiation and then flash-heated, so that the film can be uniformly heat-treated by light irradiation. At this time, since the preheating means and the flash heating means are not exposed to the irradiation light, deterioration of the parts can be prevented.

[Brief description of drawings]

FIG. 1 is a side sectional view of a heat treatment apparatus according to the present invention.

FIG. 2 is a plan view of a heat treatment apparatus according to the present invention.

FIG. 3 is an enlarged view of a main part of the heat treatment apparatus according to the present invention.

FIG. 4 is an explanatory diagram showing a configuration of flash heating means 80.

FIG. 5 is a glass substrate W produced by the heat treatment apparatus according to the present invention.
3 is a flowchart showing the heat treatment operation of FIG.

FIG. 6 is a graph showing the transition of the processing temperature of the glass substrate W and the transfer timing.

FIG. 7 is a cross-sectional view showing a glass substrate W.

FIG. 8 is an enlarged view of an essential part showing a second embodiment of the heat treatment apparatus according to the present invention.

[Explanation of symbols]

61 Upper plate 62 Bottom plate 63, 64 side plate 65 heat treatment room 66 opening 68 Gate valve 80 Flash heating means 81 xenon flash lamp 85 Second detector 90 Preheating means 91 halogen lamp 95 First detector 100 control unit 70 transportation means 71 Transport roller M1, M2 light irradiation area L1 and L3 virtual lines L2 perpendicular H overshoot T1 preheating temperature T2 processing temperature W glass substrate W1 glass plate W2 amorphous silicon film

Claims (4)

[Claims] 1. A heat treatment apparatus for heat-treating a substrate by irradiating the substrate with light, wherein the light irradiation region is disposed on the back surface side of the substrate and is generated by the light irradiation through the condenser to the substrate. And a preheating means for preheating with a substrate, which is disposed on the front surface side of the substrate and is heated to a preset preheating temperature of the substrate, and then at the same position as the light irradiation area by the preheating means on the surface of the substrate. And a flash heating means for raising the temperature of the preheated substrate to a processing temperature by irradiating with flash light through a condenser, the preheating means and the flash heating means being provided with the light irradiation. A heat treatment apparatus for a substrate, which is arranged so as to be inclined in the same direction with respect to a vertical line in a region. 2. A heat treatment apparatus for heat-treating a substrate by irradiating the substrate with light, wherein the light irradiation region is disposed on the back surface side of the substrate and is generated by the light irradiation through the condenser with respect to the substrate. And a preheating means for preheating with a substrate, which is disposed on the front surface side of the substrate and is heated to a preset preheating temperature of the substrate, and then at the same position as the light irradiation area by the preheating means on the surface of the substrate. On the other hand, a flash heating unit that raises the temperature of the preheated substrate to a processing temperature by irradiating with flash light through a condenser is provided, and the flash heating unit deviates from an imaginary line connecting the light irradiation region. An apparatus for heat treating a substrate, characterized in that the preheating means is arranged at a different position. 3. The heat treatment apparatus for a substrate according to claim 1, wherein the light irradiation region generated by the preheating unit and the flash heating unit, and the substrate arranged in the light irradiation region. An apparatus for heat treating a substrate, wherein and are relatively moved. 4. The heat treatment apparatus for a substrate according to claim 1, further comprising a first detector for detecting light on the front surface side of the substrate on a virtual line connecting the preheating means and the light irradiation region. And a second detector for detecting light on the back surface side of the substrate on an imaginary line connecting the flash heating unit and the light irradiation region, the heat treatment apparatus for a substrate.