JPH1092759A - Substrate heat treatment device and substrate heat treatment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat treatment device and a heat treatment method, which can suppress the warp deformation of a substrate. SOLUTION: The substrate heat treatment device has a port 4 and a reaction tube 7. The port 4 arranges insulating wafers 1 used for integrating and forming a thin film transistor at prescribed intervals in a vertical direction and horizontally supports the respective wafers 1. The reaction tube 7 stores the port 4, heats the wafers 1 and executes treatment including one of annealing, thermal oxidation, impurity diffusion and impurity activation, which are required at least for forming the thin film transistor. The port 4 has supporting points supporting the peripheral end parts of the wafers 1 at more than three points. The positions of the respective supporting points are set so that the center of a polygon connecting the respective supporting points is matched with the centroids of the wafers 1. The port can be provided with a supporting beam for supporting the bottoms of the wafers by line contact or face contact. For using a lateral port, supporting structure where the inclinations of the wafers become within 10 deg. against the vertical direction is provided.

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 and a substrate heat treatment method for a thin film element used in an active matrix type liquid crystal display device, a line sensor and the like.

[0002]

2. Description of the Related Art Substrates on which thin film transistors of thin film transistors are integratedly formed have been widely used as components of active matrix type liquid crystal displays, plasma displays, EL displays, line sensors, and the like. The thin film element is formed in an integrated manner by applying an LSI manufacturing process using a thin film made of polycrystalline silicon, amorphous silicon, or the like formed on the substrate surface as a semiconductor active layer. L
The SI manufacturing process includes a high-temperature heat treatment such as an impurity diffusion step, a gate insulating film forming step, or an annealing step, and the substrate must have excellent heat resistance that can withstand the highest processing temperature during the manufacturing process. . This maximum processing temperature differs depending on the material of the thin film and the content of the LSI manufacturing process to be applied. When a glass material is used as the substrate, an appropriate material is set according to the maximum processing temperature. For example, when forming an amorphous silicon thin film transistor element, the maximum processing temperature is generally about 500 ° C. In this case, barium borosilicate glass (for example, Corning 7059) having a strain point of about 600 ° C. is used. The strain point is defined as the temperature at which the viscosity of the material becomes about 10 ^13.5 Pa · s, and is a measure of heat resistance. When a transistor element is formed using a polycrystalline silicon thin film, the maximum processing temperature is 600 when CVD is used as a method for forming a gate insulating film.
Reaches approx. In this case, about 64 are used as the substrate material.
Alumina borosilicate glass (for example, Corning 1733) having a strain point of 0 ° C. is used. When a thermal oxidation process is used instead of CVD as a method for forming a gate insulating film, the substrate processing temperature reaches about 1000 ° C. At this time, quartz glass having a strain point of about 1060 ° C. is used as a substrate material. In addition, various types of glass materials are used depending on the maximum processing temperature during the LSI manufacturing process.

[0003]

However, even when the temperature of the substrate is below the strain point, the viscosity decreases as the temperature increases. In particular, since a glass material is amorphous, its viscosity decreases substantially monotonically with an increase in temperature. For this reason, 1
Even if heat treatment is applied at a temperature as low as about 00 ° C., the material is slightly deformed. For example, when warpage deformation occurs, not only a dimensional error occurs in mask alignment by a stepper, but also a robot cannot handle during transport, resulting in a control error. Furthermore, when the warpage becomes severe, the threshold voltage of the thin-film transistor element fluctuates, causing a problem that the circuit does not operate. Therefore, deformation such as warpage of the substrate must be prevented as much as possible.

Conventionally, various measures have been proposed to prevent deformation of the substrate. For example, Japanese Patent Application Laid-Open No. Hei 5-216066 discloses a technique for improving the heat resistance of a quartz substrate by improving the composition of the substrate. According to this, by controlling the OH group concentration in the quartz substrate to 200 ppm or less, it is possible to suppress the warpage of the substrate due to the heat treatment. In the case where fused quartz is used as the substrate material, in the step of dissolving the natural quartz cut in advance and densifying it again, a chemical treatment for removing as much moisture as possible is performed.
The H group concentration is controlled to 200 ppm or less. On the other hand, synthetic quartz is a raw material Si that is artificially synthesized and generated in advance.
The ingot is made by burning Cl ₄ to convert it to SiO ₂ and making it transparent. In this manufacturing process, the concentration of OH groups is controlled to be 200 ppm or less by minimizing mixing of moisture. However, actually, the OH group in quartz is
In order to control the content to be less than 00 ppm, precise process management and additional processes are required, and there is a problem in manufacturing cost.
Even if the OH group concentration is suppressed to 200 ppm or less, it is difficult to completely suppress the warpage of the substrate.

As another measure, it is conceivable to increase the heat resistance by using a substrate as thick as possible. However, for example, in a high-temperature process of a polycrystalline silicon thin-film transistor element, the same equipment as used in LSI manufacturing is used, so the thickness of the substrate is limited, and a thick substrate cannot be used without limitation. For this reason, warpage occurs during high-temperature heat treatment. Even if the thickness of the substrate is increased, the warpage cannot be completely suppressed. For example, when a gate insulating film of a thin film transistor element is formed by thermal oxidation, the processing temperature reaches 1100 ° C. or higher. In this case, even if a quartz substrate is used, the viscosity is reduced by as much as two orders of magnitude, and even if the thickness of the substrate is increased, there is no effect.

As another countermeasure, Japanese Patent Application Laid-Open No. 5-291164
Japanese Patent Application Laid-Open Publication No. H11-139,086 discloses a method using a support (backing member). In this conventional example, when a vertical heat treatment apparatus is used, a substrate (wafer) to be heat-treated is held horizontally at a predetermined pitch with respect to the boat. This boat is inserted into the reaction tube of the heat treatment apparatus and heat treatment is performed. At this time, a support (backing member) made of a substrate material having a viscosity higher than the viscosity of the wafer is laid under the wafer to perform a heat treatment to prevent warpage. When the wafer is made of, for example, quartz, silicon can be used as a support material. However, this method has a problem that the load on the robot increases because the support must be handled together with the wafer.

Further, another measure is disclosed in JP-A-5-291165. When a vertical heat treatment apparatus is used, a boat in which wafers are horizontally held by a plurality of posts at a predetermined pitch is inserted into a reaction tube.
In this state, heat treatment is usually performed two or more times. At this time, the heat treatment is performed at least once in a posture in which the wafer placed on the boat is changed in the planar direction, thereby preventing the accumulation of the heat treatment deformation. Alternatively, first heat-treat the substrate with the substrate facing upward, reverse the front and back when it is warped to some extent, and perform the heat treatment.
There is also a method of undoing the warpage. However, these countermeasures require handling for turning the wafer upside down, and have a problem that handling of the substrate becomes complicated.

[0008]

The following means have been taken in order to solve the above-mentioned problems of the prior art. According to a first aspect of the present invention, a substrate heat treatment apparatus includes a vertical boat and a reaction furnace. In this vertical boat, insulating substrates used for integrated formation of thin film transistors are vertically arranged at regular intervals and horizontally supported. The reaction furnace stores the boat and heats the substrate, and performs at least processing including annealing, thermal oxidation, impurity diffusion and impurity activation necessary for forming a thin film transistor. As a characteristic feature, the boat has support points that support the peripheral end of the substrate at three or more points, and positions of the support points are such that the center of a polygon connecting the support points coincides with the center of gravity of the substrate. Is set. Alternatively, the boat has a support beam for supporting the bottom portion of the substrate by line contact or surface contact. Preferably, a projection is formed on the surface of the support beam to reduce the contact area with the bottom surface of the substrate. The boat is made of silicon or silicon carbide.

According to a second aspect of the present invention, a substrate heat treatment apparatus includes a horizontal boat and a reaction furnace. In this horizontal boat, insulating substrates used for integrated formation of thin film transistors are arranged at predetermined intervals in the horizontal direction, and the substrates are supported substantially vertically. The reaction furnace stores the boat and heats the substrate, and performs at least processing including annealing, thermal oxidation, impurity diffusion and impurity activation necessary for forming a thin film transistor. As a feature, the boat has a support structure in which the inclination of the substrate is within 10 ° with respect to the vertical direction. Specifically, the boat has a support structure that supports the substrate substantially vertically at three or more points. Alternatively, the boat has a support groove for supporting the lower end of the substrate, and the depth and width of the support groove are set so that the inclination of the substrate is within 10 °. Even in horizontal substrate heat treatment equipment,
Preferably, the boat is made from silicon or silicon carbide.

According to a third aspect of the present invention, there is provided a vertical boat in which insulating substrates used for integrated formation of thin film transistors are vertically arranged at regular intervals and each substrate is supported horizontally. In a substrate heat treatment method, the boat is stored in a reaction furnace and the substrate is heated to perform at least a process including annealing, thermal oxidation, impurity diffusion and impurity activation necessary for forming a thin film transistor. Is placed on the boat with the vertical upwards.

According to a fourth aspect of the present invention, in a substrate heat treatment method for heating an insulating substrate used for integrated formation of a thin film transistor and performing a thermal oxidation process required for forming the thin film transistor, a heat source required for the thermal oxidation process is provided. The substrate is irradiated with light energy or plasma energy. Preferably, heat energy is supplied to the substrate in addition to light energy or plasma energy. Preferably, after the thermal energy is supplied to the substrate to perform the primary thermal oxidation at a relatively low temperature, the substrate is irradiated with light energy or plasma energy to perform the secondary thermal oxidation at a relatively high temperature.

According to a fifth aspect of the present invention, an insulating substrate used for integrated formation of a thin film transistor is formed by a resistance heating method,
The substrate is placed on a susceptor of a high-frequency heating type or a lamp heating type and heated, and at least a process including any of annealing, thermal oxidation, impurity diffusion and impurity activation necessary for forming a thin film transistor is performed.

According to a first aspect of the present invention, in a vertical substrate heat treatment apparatus, when a peripheral portion of a substrate is supported at three or more points, the center of a polygon connecting the supporting points is made to coincide with the center of gravity of the substrate. ing. Thereby, the stress applied to the substrate during the heat treatment can be equalized, and thermal deformation such as warpage can be suppressed. Alternatively, warping deformation can be suppressed by providing a support beam that supports the bottom surface of the substrate by line contact or surface contact. According to a second aspect of the present invention, in the horizontal substrate heat treatment apparatus, the boat has a support structure in which the inclination of the substrate is within 10 ° with respect to the vertical direction. This makes it difficult to apply a stress that causes deformation to the substrate. According to a third aspect of the present invention, in a substrate heat treatment method using a vertical substrate heat treatment apparatus, a surface on which a thin film transistor is to be formed is arranged on a boat with a vertical direction facing upward. In this way, even if warpage occurs, the warpage can be easily corrected when the substrate is incorporated into the liquid crystal display panel in a later step. In the fourth aspect of the present invention, the substrate is irradiated with light energy or plasma energy as a heat source required for the thermal oxidation treatment, and the amount of heat itself that causes warpage is suppressed. In the fifth aspect of the present invention, an insulating substrate used for integrated formation of a thin film transistor is placed on a susceptor of a resistance heating system, a high frequency heating system or a lamp heating system and heated. Thereby, the warpage of the substrate can be physically suppressed.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic diagram showing a first embodiment of a substrate heat treatment apparatus according to the present invention. As shown, this embodiment is a vertical heat treatment apparatus,
A gas supply pipe 8 is provided in a bottomed quartz reaction tube 7 having a bottom opening and extending upward. Individual wafer (substrate)
1 is horizontally held in a state of being separated from the boat 4 at a predetermined pitch, and is conveyed through a heat retaining tube 9. The opening of the reaction tube 7 is sealed by a cap 10 fixed to the heat retaining tube 9 when the boat 4 is completely inserted into the inside.
A heater 11 is provided around the reaction tube 7 to maintain the ambient temperature at a high temperature. When, for example, a thermal oxidation treatment is performed using this heat treatment apparatus, a process gas is introduced from the gas supply pipe 8 while maintaining the inside of the reaction tube 7 at a high temperature atmosphere of, for example, 1000 ° C., and is maintained for a predetermined reaction time. .
As described above, in the vertical substrate heat treatment apparatus, the insulating wafers 1 used for integrated formation of thin film transistors using the boat 4 are vertically arranged at regular intervals and each substrate is horizontally supported. . The reaction tube 7 stores the boat 4 and heats the wafer 1 to perform at least a process including annealing, heat treatment, impurity diffusion and impurity activation necessary for forming a thin film transistor.

From the viewpoint of space saving and uniformity of heat treatment, the above-mentioned vertical heat treatment apparatus has become mainstream. The heat treatment apparatus includes, for example, a diffusion / oxidation furnace and an LP-CVD furnace. A vertical heat treatment apparatus is disclosed, for example, in Japanese Patent Application Laid-Open No. 3-235329. In this vertical type, only the end of the wafer 1 is supported by the boat 4 and held horizontally. Accordingly, the support structure is basically susceptible to thermal deformation due to the weight of the wafer 1. Because of this,
If a vertical heat treatment apparatus is used, even if the strain point is 100
Even if heat treatment is performed at a temperature as low as about ° C., warpage of the wafer occurs due to its own weight. Particularly, in the process of manufacturing a thin film element such as a thin film transistor, a plurality of heat treatments such as an impurity diffusion step, a step of forming a gate insulating film by thermal oxidation, and an annealing step are repeatedly performed. Even if the amount of warpage generated by one heat treatment is small, the deformation is accumulated each time the heat history is repeated, and eventually the amount of warpage becomes large. When the substrate is warped, a trouble such as an exposure defect due to a wafer transfer trouble or a stage suction failure of the exposure apparatus occurs in a later process. In addition, the stress inside the thin film increases due to the deformation of the substrate, and the electrical characteristics of the thin film element become poor. When the diameter of a wafer is increased to an 8 inch size or the like, the absolute amount of warpage is further increased, so that various defects, failures or defects occur frequently.

Therefore, in order to minimize thermal deformation such as warpage of the substrate, in the present embodiment, the structure of the boat 4 is devised to support the peripheral end of the wafer (substrate) 1 at three or more points. The positions of the support points are set such that the center of the polygon connecting the support points coincides with the center of gravity of the wafer 1. Thereby, the stress applied to the wafer 1 during the heat treatment is equalized, and the warpage is prevented as much as possible. As described above, even when a heat treatment at a temperature exceeding 1000 ° C. is performed, the warpage of the wafer 1 can be suppressed to be smaller than in the related art.

Hereinafter, an example of high-temperature heat treatment will be described for reference. The high-temperature heat treatment is performed, for example, to obtain a high-quality gate insulating film. Polycrystalline silicon thin film transistor is MOS
It has a structure, and a gate insulating film is essential. The most common gate insulating film in a semiconductor process is a thermal oxide film. However, polycrystalline silicon is a collection of grains (crystal grains). When thermally oxidized, grains are oxidized, but boundaries between grains are hardly oxidized. In addition, the completed oxide film becomes uneven. For this reason, the electric field tends to concentrate on a part of the unevenness, and a breakdown occurs there. That is, the pressure resistance is reduced. Therefore, it is said that oxidation is preferably performed at a temperature as high as possible (for example, 1100 ° C. to 1150 ° C.) in order to eliminate irregularities. This is because the higher the temperature, the lower the viscosity of the oxide film and the more the fluidity appears, so that the unevenness becomes smoother. High-temperature heat treatment is also performed to increase the mobility of polycrystalline silicon. When polycrystalline silicon is thermally annealed at a high temperature, the boundaries between the grains fuse because the silicon atoms themselves diffuse, and the grains grow into larger grains. Therefore, the mobility is increased, and the operation characteristics of the thin film transistor are improved.

FIG. 2 is an external perspective view showing an example of the boat used in the first embodiment shown in FIG. Boat 4
Is a pair of disks 5, 6 which are vertically spaced apart from each other at a predetermined interval, and a plurality of disks (4 in this example) connected therebetween.
Book 2). As a material of the boat 4, for example, silicon (Si) or silicon carbide (SiC) having excellent heat resistance is used. Grooves are formed on the side surfaces of the individual posts 2 at a predetermined pitch. The edge of one wafer engages with the groove at the same level and is supported horizontally.

FIG. 3 shows a plan view of the boat 4 shown in FIG. The plurality of posts 2 are arranged at predetermined intervals along the circumferential direction of the disk 5. The ends of the wafer 1 are supported at multiple points by grooves formed in the individual posts 2. In this embodiment, the wafer 1 is supported at four points by four posts 2. In the present embodiment, the positions of the support points (ie, the positions of the posts 2) are set such that the center of the rectangle connecting the four support points coincides with the center of gravity of the wafer 1. In the illustrated four-point support, each support point is located on two diagonal lines. In this way, by supporting the center of the polygon connecting the support points so as to coincide with the center of gravity of the wafer 1,
The stress applied to the wafer 1 can be equalized, and distortion such as extreme warpage can be suppressed.

FIG. 4 is a schematic partial perspective view showing an improved example of the boat 4. As shown in FIG. The boat 4 includes a wafer (not shown)
Is provided with a support beam 15 for supporting the bottom surface portion of the device by line contact or surface contact. In this example, this support beam 15 is composed of four posts 2
Has a cross shape connected to the By mounting the wafer on the beam 15 having the cross shape, the warpage can be suppressed. In this case, the boat 4 is made of S having excellent heat resistance.
Preferably, it is made of i or SiC. In addition, support beam 1
The shape of 5 is not limited to the cross shape, but it is generally preferable that the contact area with the bottom surface of the wafer is small in order to prevent foreign matters from adhering.

FIG. 5 is a schematic partial perspective view showing another example of the boat 4. In this example, the support beam 15a has a disk shape supported by the four posts 2, and supports the wafer (not shown) by surface contact from the bottom surface. The projection 15 is provided on the surface of the disk-shaped support beam 15a.
Since a large number of b are formed, the contact area with the bottom surface of the wafer is reduced. Such a structure is suitable when not only the front surface but also the back surface of the wafer is to be subjected to thermal oxidation treatment.

FIG. 6 is a process chart showing an embodiment of the substrate heat treatment method according to the present invention. As shown in FIG. 1A, an insulating wafer (substrate) 1 used for integrated formation of a thin film transistor 21 and a pixel electrode 22 is arranged at regular intervals in a vertical direction, and each wafer is horizontally supported. boat
(Not shown) for heat treatment. This wafer 1 is used for assembling an active matrix type liquid crystal display device. The boat on which the wafers 1 are set is stored in a reaction furnace and heated, and at least a process including any of annealing, thermal oxidation, impurity diffusion, and impurity activation necessary for forming the thin film transistor 21 is performed. At this time, the thin film transistor 21 is arranged on the boat with the surface on which the thin film transistor 21 is formed facing upward in the vertical direction. (A) shows the state after the heat treatment,
The wafer 1 is warped downward by its own weight.
(B) shows the substrate (wafer) 1 shown in FIG.
3 shows a state of joining. An opposing electrode 24 is formed on the opposing substrate 23, and is bonded via a sealing material 25 to the substrate 1 on which the thin film transistors 21 and the pixel electrodes 22 are integrally formed. Spacers 26 having a constant particle size are dispersed in a gap between the two substrates 1 and 23. (C) shows a state where the liquid crystal 27 is sealed in the gap between the upper and lower substrates 23 and 1. When the liquid crystal 27 is sealed, the inside of the cell in which the upper and lower substrates 23 and 1 are bonded is evacuated. Therefore, the substrate 1 that has been warped downward in a convex shape is deformed by receiving pressure from the atmosphere during the evacuation process. As described above, the warpage deformed downward into a convex shape can be corrected at the stage of assembling the liquid crystal cell. On the other hand, the substrate 1 deformed in a convex shape cannot be corrected. Therefore, in the case of processing a substrate for a liquid crystal panel using a vertical heat treatment apparatus, it is preferable that a substrate on which a thin film transistor or the like is formed be placed on a boat with the surface on which the thin film transistor or the like is formed facing upward. In addition, shortening the heat treatment time as much as possible is effective for suppressing the warpage. For example, in order to suppress the amount of warpage to 100 μm or less, when performing a heat treatment at 1100 ° C. on a quartz substrate having a thickness of 1.6 mm, the treatment time may be set within 10 minutes.

FIG. 7 shows a second embodiment of the present invention, and shows the shape of a boat used in a horizontal heat treatment apparatus. The horizontal heat treatment apparatus has a structure in which a plurality of substrates or wafers to be processed are placed in a furnace in a state of being leaned on a boat 4, and is characterized in that the backflow of air during wafer transfer is small. That is, in a horizontal heat treatment apparatus,
In the boat 4, insulating substrates (not shown) used for integrated formation of thin film transistors are arranged at regular intervals in the horizontal direction and each substrate is supported substantially vertically. The reaction furnace stores the boat 4 and heats the substrate, and performs at least processing including annealing, heat treatment, impurity diffusion and impurity activation necessary for forming a thin film transistor. The boat 4 of this embodiment has a support structure in which the inclination of the substrate is within 10 ° with respect to the vertical direction. Specifically, the boat 4 has a support structure for supporting the substrate substantially vertically at three or more points. In the present embodiment, using four rods 2a,
Since each substrate is supported at four points, the wafer can be reliably held in a vertical position. In this way, a stress that causes warpage is not applied to the wafer.

FIG. 8 is a schematic partial sectional view showing another example of a horizontal boat. In this example, the boat 4 is the wafer 1
And the depth and width of the support groove 4a are set so that the inclination θ of the wafer 1 is within 10 °. If the inclination θ is within 10 °,
The wafer 1 hardly undergoes warp deformation due to gravity acting in the vertical direction. For horizontal boats,
It is preferable to use Si or SiC excellent in heat resistance as the material.

FIG. 9 is a schematic view showing another embodiment of the substrate heat treatment method according to the present invention. In the present embodiment, the insulating wafer 1 used for integrated formation of the thin film transistor is heated to perform a thermal oxidation process necessary for forming the thin film transistor. As a feature, the substrate is irradiated with light energy or plasma energy as a heat source required for the thermal oxidation treatment. Thereby, the heat treatment time can be shortened, and the warpage of the wafer 1 can be suppressed accordingly. Excimer laser light or strong lamp light can be used as light energy. When irradiating plasma energy, plasma oxygen is preferably used. By using plasma oxygen, thermal oxidation treatment can be promoted, which leads to a reduction in heat treatment time. If heat energy is supplied to the substrate in addition to light energy or plasma energy, the processing time can be further reduced. In some cases, after thermal energy is supplied to the wafer 1 to perform primary thermal oxidation at a relatively low temperature, light energy or plasma energy is applied to the wafer 1 to perform secondary thermal oxidation at a relatively high temperature. It may be. The wafer 1 hardly deforms in the primary thermal oxidation process. Although some deformation occurs in the secondary thermal oxidation treatment, since the primary thermal oxidation treatment is performed in advance, the time for the secondary thermal oxidation treatment can be shortened, and the amount of warpage deformation decreases accordingly.

FIG. 10 is a schematic view showing another embodiment of the substrate heat treatment method according to the present invention. In this embodiment,
Insulating wafer 1 used for integrated formation of thin film transistors
Is placed on a susceptor 31 of a resistance heating system, a high frequency heating system or a lamp heating system and heated, and at least a process including any of annealing, thermal oxidation, impurity diffusion and impurity activation necessary for forming a thin film transistor is performed. Do. By mounting the wafer 1 on the susceptor 31, the wafer 1 is physically
To prevent warp deformation. In this embodiment, the wafer 1 is 1
Although a single-wafer method in which heat treatment is performed one by one is adopted, a batch-type susceptor may be used instead.

[0027]

As described above, according to the first aspect of the present invention, in the vertical substrate heat treatment apparatus, when the peripheral end of the substrate is supported at three or more points, the center of the polygon connecting the supporting points is located at the center. It is made to match the center of gravity of the substrate. In a vertical substrate heat treatment apparatus, a support beam for supporting the bottom surface of the substrate by line contact or surface contact is provided on the boat. According to the second aspect, in the horizontal substrate heat treatment apparatus, the boat has a support structure such that the inclination of the substrate is within 10 ° with respect to the vertical direction. According to the third aspect, when heat treatment is performed using a vertical heat treatment apparatus, the surface on which the thin film transistors are to be formed is disposed on the boat with the surface facing upward in the vertical direction. According to the fourth aspect, when performing thermal oxidation treatment required for forming a thin film transistor, light energy or plasma energy is irradiated as a heat source to shorten the heating time. According to the fifth aspect of the present invention, a heat treatment is performed by placing an insulating substrate used for integrated formation of thin film transistors on a susceptor of a resistance heating system, a high frequency heating system, or a lamp heating system. As described above, it is possible to prevent the occurrence of the warpage of the substrate due to the heat treatment, and to obtain an effect that the thin film element substrate can be manufactured at a high yield and at a low cost.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a vertical substrate heat treatment apparatus according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing an example of a boat used in the vertical substrate heat treatment apparatus shown in FIG.

FIG. 3 is a schematic diagram showing a plan shape of the boat shown in FIG. 2;

FIG. 4 is a partial perspective view showing an improved example of a boat used in a vertical substrate heat treatment apparatus.

FIG. 5 is a partial perspective view showing another improved example of the boat.

FIG. 6 is a process chart showing an embodiment of a substrate heat treatment method according to the present invention.

FIG. 7 is a perspective view showing a boat used in a horizontal substrate heat treatment apparatus according to a second embodiment of the present invention.

FIG. 8 is a partial sectional view showing another example of the boat.

FIG. 9 is a schematic view showing another embodiment of the substrate heat treatment method according to the present invention.

FIG. 10 is a schematic view showing another embodiment of the substrate heat treatment method according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Wafer (substrate), 2 ... Post, 4 ... Boat, 7 ... Reaction tube, 11 ... Heater, 15 ... Support beam, 15a ... Support beam,
31 ... susceptor

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01L 21/336

Claims (13)

[Claims] 1. A vertical boat in which insulating substrates used for integrated formation of thin film transistors are arranged at regular intervals in a vertical direction and horizontally support a substrate, and the boat is stored and the substrate is heated. At least a substrate heat treatment apparatus comprising: a reaction furnace for performing a process including any of annealing, thermal oxidation, impurity diffusion, and impurity activation necessary for forming a thin film transistor; A substrate heat treatment apparatus comprising: support points for supporting at least points, wherein the positions of the support points are set such that the center of a polygon connecting the support points coincides with the center of gravity of the substrate. 2. A vertical boat in which insulating substrates used for integrated formation of thin film transistors are arranged at regular intervals in the vertical direction and each substrate is horizontally supported, and the boat is stored and the substrate is heated. A reaction furnace for performing at least one of annealing, thermal oxidation, impurity diffusion, and impurity activation necessary for forming a thin film transistor. An apparatus for heat treating a substrate, comprising a support beam for supporting in contact or surface contact. 3. The substrate heat treatment apparatus according to claim 2, wherein a projection is formed on a surface of the support beam to reduce a contact area with a bottom surface of the substrate. 4. A vertical boat in which insulating substrates used for integrated formation of thin film transistors are arranged at regular intervals in a vertical direction and each substrate is supported horizontally, and the boat is stored and the substrate is heated. At least a substrate heat treatment apparatus including a reaction furnace for performing a process including any of annealing, thermal oxidation, impurity diffusion, and impurity activation necessary for forming a thin film transistor, wherein the boat is made of silicon or silicon carbide. A substrate heat treatment apparatus characterized by the above-mentioned. 5. A horizontal boat for arranging insulating substrates used for integrated formation of thin film transistors at a predetermined interval in a horizontal direction and supporting the substrates substantially vertically, and storing the boats to heat the substrates. At least a substrate heat treatment apparatus having a reaction furnace for performing a process including any of annealing, thermal oxidation, impurity diffusion, and impurity activation necessary for forming a thin film transistor, wherein the boat has a vertical substrate inclination. A substrate heat treatment apparatus characterized by having a support structure that is within 10 ° of the substrate. 6. The substrate heat treatment apparatus according to claim 5, wherein the boat has a support structure for supporting the substrate substantially vertically at three or more points. 7. The boat has a support groove for supporting the lower end of the substrate, and the depth and width of the support groove are set so that the inclination of the substrate is within 10 °. The substrate heat treatment apparatus according to claim 5. 8. A horizontal boat in which insulating substrates used for integrated formation of thin film transistors are arranged at a constant interval in a horizontal direction and support the substrates substantially vertically, and the boat is stored and the substrate is heated. A substrate heat treatment apparatus having at least a reactor for performing a process including any of annealing, thermal oxidation, impurity diffusion, and impurity activation necessary for forming a thin film transistor, wherein the boat is made of silicon or silicon carbide. A substrate heat treatment apparatus. 9. A vertical boat in which insulating substrates used for integrated formation of thin film transistors are arranged at regular intervals in a vertical direction and each substrate is supported horizontally, and this boat is stored in a reaction furnace. A substrate heat treatment method for performing a treatment including at least one of annealing, thermal oxidation, impurity diffusion and impurity activation necessary for forming a thin film transistor, wherein the surface on which the thin film transistor is formed is oriented vertically. A substrate heat treatment method, wherein the substrate is disposed on a boat. 10. A substrate heat treatment method for heating an insulating substrate used for integrated formation of a thin film transistor and performing a thermal oxidation process required for the formation of the thin film transistor, wherein light energy or plasma energy is used as a heat source required for the thermal oxidation process. Irradiating the substrate with the substrate. 11. The method according to claim 10, wherein heat energy is supplied to the substrate in addition to light energy or plasma energy. 12. A method of performing primary thermal oxidation at a relatively low temperature by supplying thermal energy to a substrate, and then performing secondary thermal oxidation at a relatively high temperature by irradiating the substrate with light energy or plasma energy. The substrate heat treatment method according to claim 10, wherein: 13. An insulative substrate used for integrated formation of a thin film transistor is placed on a susceptor of a resistance heating system, a high frequency heating system or a lamp heating system and heated, and at least annealing and thermal oxidation necessary for forming the thin film transistor are performed. Substrate heat treatment method for performing a process including any of impurity diffusion and impurity activation.