JP2011049333A - Double side heater for substrate, and heated gas blowing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem where a substrate is warped or cracked by a temperature difference between a surface and a reverse face of the substrate, in a method of blowing a high temperature of gas beam line-likely toward the substrate and of moving relatively the substrate, because the substrate is difficult to be heated over the whole thereof when a size of the substrate comes, in particular, to about 1 m or more, in a manufacturing process to heat uniformly the large-sized substrate in a short time without deforming the substrate. <P>SOLUTION: The temperature difference between the surface and the reverse face of the substrate is restrained low by blowing high temperature gas linearly onto the surface and the reverse face. The large-sized substrate is uniformly anneal-treated in the short time, by this manner. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

In general, some devices manufactured by forming a film on a substrate have a large size of 1 m class. For example, there is a device using a substrate of glass, resin, or metal sheet. As a device having a thin film grown on a glass substrate, there are so-called large-area electronic devices such as a liquid crystal display device (LCD), an organic EL (electrominescence) display device, and a solar cell.
The thin film is used as an amorphous film, a crystal film, an insulating film, a conductive film, or a protective film in any device.

  Since these substrates cannot be subjected to high-temperature heat treatment like silicon wafers, plasma chemical vapor deposition (CVD) films that can be formed while holding the substrate at a low temperature in a vacuum chamber are used. Since this film grows while adsorbing the gas species generated by plasma decomposition, it contains undesired impurities such as hydrogen and oxygen, is easy to absorb moisture, and is inferior in density. In order to improve this, there is a technique for removing impurities by annealing with a plasma beam (see Prior Patent Document 1) or laser light. In addition, in the case of an insulating film, chemical vapor deposition (CVD) using reduced pressure is established, but since reduced pressure is used, the apparatus becomes expensive. For this purpose, a method of heating a film formed on the substrate by another method is taken. For example, there is a material in which a solution in which a target film material is dissolved is formed on a substrate by a method such as spin coating (also called spin-on) or spraying, and then heated at 200 to 500 ° C. . Examples of the insulating film include an organic polymer, an inorganic polymer, or a polymer coating film in which these are mixed. As the conductive film, for example, there is a coating film of a ZnO film containing Al. There is a metal coating film in which fine particles of copper (Cu) or silver (Ag) are surrounded by a dispersion material and dissolved in a solvent. As the crystal film, for example, there is a coating film of CIGS (compound of Cu, In, Ga, Se) which is a compound semiconductor. These coating films are used on a large substrate of about 40 cm to 2 m. In order to manufacture inexpensively, the material of a board | substrate is glass or a heat resistant resin. These films are used by annealing the film applied thereon by raising the temperature of the substrate. However, when the substrate is 40 cm to 2 m in size, it is difficult to raise the substrate temperature uniformly and uniformly. In order to apply heat uniformly everywhere, for example, when annealing in a furnace, it takes several hours to prevent temperature differences throughout the substrate. In this correspondence, there arises a problem that the number of production per unit time decreases. Annealing is particularly difficult when the substrate is made of glass or resin having poor heat resistance. Although it has been proposed or performed to anneal the substrate while maintaining the substrate at a low temperature using a plasma jet or a laser, there is a problem that the productivity of a large-area substrate is inferior (see Patent Documents 1 and 2).

The present invention relates to an improvement in film formation suitable for manufacturing a large area electronic device, for example, and relates to annealing of a material applied on a glass substrate, for example. In particular, the present invention relates to an apparatus for modifying a film by annealing a coating film including a silicon oxide film, a silicon nitride film, a conductive film, or a multi-component compound film coated on a large glass substrate. Not only glass substrates but also large area devices using resin substrates and metal substrates have the same problem.

JP 2006-06130 A JP 2006-278625 A

  Representative of large substrate heating devices are a furnace annealing device and a lamp annealing device. There are problems with large substrates. Regardless of whether one or many sheets are placed in the furnace, the temperature rises differently around the substrate and in the center. In order to make it uniform, the temperature must be raised slowly over time. In addition to the decrease in productivity, this has a problem that it does not match the timing of other processes. In lamp annealing in which a large number of lamps are arranged so as to cover a large substrate, the difference between the periphery and the center of the substrate can be suppressed by adjustment, but a temperature difference occurs between the lamp and the lamp. In addition, when the substrate is transparent, there is a problem that light is hardly absorbed, and absorption depends on the type and thickness of the surface material. As a method for solving these problems, there is a method in which heated gas is sprayed in a beam shape perpendicularly to the substrate. The gas at a constant temperature sprayed in the form of a beam continuously applies heat to the substrate surface by heat conduction, so that the coating film on the substrate surface is annealed at high speed. When the substrate is as small as about 10 cm, the warpage of the substrate caused by the temperature difference between the back surface and the surface to which the gas is blown is relatively small. However, when the size of the substrate is 50 cm or 2 m, the amount of warpage of the substrate due to the temperature difference between the front and back of the substrate becomes relatively large. Since the distance between the gas outlet and the substrate affects the substrate surface temperature, this warpage must be kept below a certain level. This is a challenge.

This problem is shown in FIG. The substrate 1 placed on the support base 6 in contact with the back surface 1b of the substrate moves under the gas sprayer 2. A coating film 5 is formed on the surface 1 a of the substrate 1. The gas beam 3 heated by the gas heating mechanism 4 of the gas sprayer 2 sprays the substrate surface almost vertically to heat the substrate surface. The coating film 5 applied on the substrate surface is annealed by the gas beam 3 to release a gas such as a solvent. The temperature of the substrate varies depending on the degree of adhesion between the support base 6 and the back surface 1b of the substrate, and is influenced by defective conductors such as air on the back surface 1b of the substrate. The surface 1a of the substrate is heated by the blowing gas 2 and the heated portion 1c of the substrate expands upward. The gap 7 between the completed support base 6 deteriorates the thermal conductivity, the temperature of the back surface rises, and the bulge is reduced to a constant bulge. If this bulge leaves a permanently deformed strain on the substrate heated to a high temperature, the substrate loses its flatness. This is a challenge. A structure of a gas spraying device that does not deform the substrate beyond a certain level is required.

FIG. 2 shows the basic structure of the apparatus of the present invention that solves the problem. The substrate 1 passes through the gas spraying device 2 while sliding on the left and right support bases 25 and 26 with a gap. A high temperature support base 27 for heating the back surface of the substrate is provided between the support bases 25 and 26. The temperature of the high temperature support 27 is adjusted by an electric heater 28 provided therein. The temperature is adjusted so that the temperature of the front surface and the back surface of the substrate is in an equilibrium state when the substrate hits the gas beam 3. By this adjustment, the swelling of the heated portion 1c of the substrate that is exposed to the gas beam is suppressed. There are several alternative techniques for creating an equilibrium state. Even in furnace annealing, both the front and back surfaces of the substrate are annealed in an oven having an infrared heater above and below. The present invention is characterized in that in the apparatus in which gas is blown perpendicularly to the front surface of the substrate, the back surface of the substrate is heated only at the place where the beam hits. In order to obtain the effect of reducing the temperature difference between the front and back surfaces, a mechanism that suppresses heat radiation from the back surface may be used without actively heating the back surface. For this effect, a heat insulating mechanism using air may be used without placing a support base at the place where the beam hits. In order to obtain the same effect, a mechanism for reflecting infrared rays may be provided to assist in heating the back surface. In order to obtain the same effect, a mechanism that applies heated gas to the back surface may be used. Between the gas of the two upper and lower gas spraying devices that faced the substrate with the same spraying device as the gas spraying device 2 placed on the lower side, so that the front and back are at the same temperature condition You may let it pass. The substrate is instantaneously heated on the front and back as it passes through the spray beam. Therefore, the coating film 5 on the substrate 1 is instantaneously heated when it passes. In principle, there is no temperature difference between the front and back surfaces of the substrate because the gas beams of the same temperature hit the top and bottom of the substrate. In the above description, the substrate is moved. However, the spraying device and the substrate may be moved relative to each other, and the structure for moving the device for heating the substrate may be used.

  The invention according to claim 1 is a substrate heating apparatus that includes a mechanism for moving the substrate, and heats the substrate surface by spraying a heated gas beam having a rectangular or linear cross section on the surface of the substrate, A substrate heating apparatus comprising a back surface heating mechanism that heats a back surface of a substrate that is exposed to the heated gas beam, wherein the substrate passes between the heated gas beam and the back surface heating mechanism.

The invention according to claim 2 is the apparatus according to claim 1, wherein the back surface heating mechanism is sandwiched between the support bases.

The invention according to claim 3 is the apparatus according to claim 1 or 2, wherein the back surface heating mechanism is an electric heater.

The invention according to claim 4 is the apparatus according to claim 1 or 2, wherein the back surface heating mechanism is a mechanism for blowing a beam of gas heated.

The invention according to claim 5 is the apparatus according to claims 1 to 4, wherein the gas is a gas containing nitrogen, oxygen, hydrogen, argon, and water.

The invention according to claim 6 is the apparatus according to any one of claims 1 to 5, wherein the substrate is made of glass, resin, or metal.

The invention according to claim 7 is a metal plate in which a groove serving as a gas flow path having an inlet and an outlet is formed from one end of the surface of the heated metal heating plate to the opposite end, and is insulated with a heat insulating material. In close contact with the surface of the metal heating plate, the groove forms a channel shielded from the outside, and at least two or more horizontal grooves are formed in the longitudinal direction of the metal plate in the middle of the channel, The number of vertical grooves that are narrower than the horizontal grooves and more than the horizontal grooves are connected to each other across the wall between the horizontal grooves and the horizontal grooves. This is a heated gas spraying device in which a flow path that collides with the wall of the horizontal groove and joins at the horizontal groove is formed, the gas is heated by passing through the flow path, and the heated gas is blown out in a beam shape.

The invention according to claim 8 is the apparatus according to claim 7, wherein the metal heating plate is heated with a heating wire.

According to the first and second aspects of the present invention, the substrate surface can be instantaneously heated without thermally deforming the substrate, and the substrate can be passed over the support base. In the case of annealing in the furnace, the substrate could not be moved, but in the present invention, it can be moved. In lamp annealing, the temperature becomes non-uniform at the boundary between the lamps, and it is difficult to uniformly anneal a large 1 m class substrate. There is also a problem that the infrared absorption of the material on the substrate differs depending on the difference in the optical properties of the material. However, since the present invention is heating by heat conduction of a gas beam, there is no material dependence.

According to the invention of claim 3, since the heating mechanism of the expandable electric heater can prevent a large substrate from warping, the device can be extended at a low cost.

According to the invention of claim 4, since the front and back surfaces of the substrate are heated by the same gas beam, surface heating is possible even when the substrate moves at a high speed. Even if the substrate moving speed is changed, the upper and lower heating mechanisms are symmetrical, so that the temperature difference between the front and back sides can be reduced ideally.

According to the invention which concerns on Claim 5, water can be included as gas. Organic substances on the substrate can be removed with water. When oxygen is included in the gas, it is difficult to oxidize the organic substance to form a gas or to burn the metal to diffuse it. When hydrogen is included in the gas, impurities can be removed as a hydride. The gas types of the upper and lower gas spraying apparatuses can be selected according to the purpose, whether they are the same or different.

According to the invention which concerns on Claim 6, it can handle so that a large sized glass substrate may not be broken and may not be changed. Even a metal or resin can be prevented from being deformed. The present invention is particularly effective when using a substrate that is desired to maintain a flat surface.

According to the invention which concerns on Claim 7 and 8, the gas groove which can cover and heat a large board | substrate is created by extending freely the horizontal groove of a gas heating apparatus corresponding to the magnitude | size of a large board | substrate in a longitudinal direction. Can do.

FIG. 1 is a schematic view of an apparatus for heating a substrate surface placed on a support with a heated gas beam. The gas beam strikes the substrate surface and instantly heats the substrate surface. Due to the temperature difference between the back surface and the front surface, the substrate with the beam swells upward. FIG. 2 is a schematic view of an apparatus to which a mechanism for suppressing the swelling of the substrate is added in a heating mechanism for blowing a heated gas beam. Added a mechanism to raise the temperature of the backside of the substrate directly below the substrate that the beam hits. Here, a first embodiment in which an electric heater is disposed as the mechanism is shown. FIG. 3 is a schematic view of an apparatus in which a first gas blowing mechanism and a second gas blowing mechanism for blowing a heated gas beam are arranged to face each other with a substrate interposed therebetween. By passing between the spraying mechanisms arranged symmetrically with respect to the substrate, the temperature difference between the front and back of the substrate can be kept small. FIG. 4 is a schematic view of a mechanism for heating the gas. (A) is a longitudinal sectional view of the mechanism, and (B) is a YY sectional view. The gas from the gas introduction pipe gathers as a gas having a constant pressure in a wide groove in a wide space, obtains a high flow velocity in a 1 mm wide vertical groove, and collides with the wall of the front horizontal groove at the outlet. This collision efficiently transfers heat from the wall to the gas. There should be at least two lateral grooves. In this case, a uniform slit-shaped gas beam is created while performing five stages of impact heat transfer.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the accompanying drawings, the same or corresponding parts are denoted by the same reference numerals.

Example 1 will be described with reference to FIG. A gas blowing device 2 is disposed on the substrate 1. The gas heating mechanism 4 is made of aluminum. The gas is heated by passing through the heating mechanism 4. A schematic diagram of the structure of the heating mechanism is shown in FIG. The heated gas beam 3 strikes the surface 1a of the moving substrate 1. The coating film 5 on the substrate surface is heated with a gas beam. The substrate 1 moves on the support bases 25 and 26. A mechanism 27 for heating the back surface of the substrate is provided between the support tables 25 and 26. Heating is performed by an electric heater 28 inside the heating mechanism 27. The support bases 25 and 26 are fixed. The heating mechanism 27 is separated from the support base and heats the adjacent support base. The temperature of the heating mechanism is set to 250 ° C., the temperature of the gas beam is set to 250 ° C., and the substrate having a width of 0.7 mm and a width of 40 cm narrower than the gas beam width of 45 cm is moved from right to left at a speed of 300 mm / min. It was. The gas of the gas beam was nitrogen and the flow rate was 50 SLM. When the warping of the substrate was observed from the side, it was not recognized. SiOC film coated on the substrate (Miraspin manufactured by APM, Korea)
TRX) showed a hardness characteristic with a pencil hardness of 8H. It was confirmed that the coating film on the substrate could be annealed without deforming the substrate.

Example 2 is shown in FIG. Gas spraying devices were arranged symmetrically above and below the substrate. The upper gas spraying device 31 and the lower gas spraying device 32 were the same. The internal gas heating mechanisms 35 and 36 are the same. The substrate 1 moves on the support bases 37 and 38 from right to left. The upper gas beam 33 hits the substrate surface 1a, and the lower gas beam 34 hits the back surface 1b of the substrate. The substrate moves between the upper and lower gas beams 33 and 34. The temperature of the heating mechanism was set to 250 ° C., the temperature of the gas beam was set to 250 ° C., and a glass substrate having a thickness of 0.7 mm and a width of 40 cm was moved from right to left at a speed of 300 mm / min. The gas of the gas beam was nitrogen and the flow rate was 50 SLM. When the warping of the substrate was observed from the side, it was not recognized. SiOC film coated on the substrate (Miraspin manufactured by APM, Korea)
TRX) showed a hardness characteristic with a pencil hardness of 8H. It was confirmed that the coating film on the substrate could be annealed without deforming the substrate. Here, nitrogen was used as the gas. Argon may be selected as the inert gas. It is also possible to mix reactive gases. When oxygen is included in the gas, it is difficult to oxidize the organic substance to form a gas or to burn the metal to diffuse it. There is a metal coating film in which metal fine particles are covered with a dispersion material and dissolved in a solvent, but an oxygen beam also works effectively to remove the dispersion material. When hydrogen is included in the gas, impurities can be removed as a hydride. The gas can also contain water. Water having a temperature higher than the boiling point is effective for removing organic substances on the substrate. The gas types of the upper and lower gas spraying apparatuses can be selected according to the purpose, whether they are the same or different.

Example 3 is shown in FIG. FIG. 4 is a schematic diagram of the structure of the heating mechanisms 35 and 36 of the heated gas spraying devices 31 and 32 used in Example 2 in which both surfaces of the substrate are heated with a gas beam. (A) shows the cross section of the heating mechanism in the thickness direction. (B) is a YY sectional view. The metal heating plate 41 was made of aluminum having a thickness of 20 mm. Six lateral grooves 42 and 43 having a depth of 5 mm, a width of 5 mm, and a length of 450 mm were cut at equal intervals of 6 mm on both surfaces of the metal plate. The adjacent horizontal grooves in the upper and lower sides were connected by arranging vertical grooves 44 and 45 having a depth of 3 mm and a width of 1 mm with a distance of 14 mm. The vertical groove of the next stage was arranged so as to be in the center of the gap. In the drawing, the number of vertical holes is omitted and reduced. Shallow slit grooves 46 and 47 having a depth of 1 mm, a width of 30 mm, and a length of 450 mm were cut to the lower end of the metal plate 41 in connection with the horizontal grooves 42-6 and 43-6 arranged at the bottom. Gas inlet pipes 48 and 49 of 3/8 inch were connected to the uppermost lateral grooves 42-1 and 43-1 through connecting holes 50 and 51, and gas was introduced in two systems. The introduction pipes were arranged at both longitudinal ends so as to make the temperature distribution in the longitudinal direction of the heating mechanism uniform. A groove formed by cutting the surface of the metal plate 41 was brought into close contact with the metal side plates 52 and 53, and the groove was used as a gas flow path. The outside of the metal side plate was cut into a box shape, and heat insulating materials 54 and 55 were disposed therein and sealed with metal lids 56 and 57. The heat insulating material 58 was sealed also on the top of the metal plate, and the heat insulating materials 59 and 60 were sealed on the end surface of the metal plate 41. An insulated heating wire 61 is folded back through the metal plate 41 and heated by a power source (not shown) to heat the metal plate 41. The temperature of the gas was measured with a thermocouple (TC) and controlled with a power supply so that the set temperature was reached. Two beams were used as one beam by the aperture part 62. There are times when the aperture part 62 is removed and two beams are used according to the purpose. For example, assembling a process that first reduces the gas flow rate of the beam that passes through the substrate to reduce the heating effect, volatilizes the solvent of the coating film, and then increases the gas flow rate of the beam that passes through and completes the firing. Is possible.

In this embodiment, aluminum is selected as the metal plate material, but other materials may be selected according to the temperature range and the type of gas used. Although the heating method is heating wire, lamp heating or induction heating may be selected. A preheated gas may be introduced from the gas introduction part. Moreover, although it was set as the structure which put the heat insulating material in the side plate, you may form a side plate with a heat insulating material or ceramics. Although six horizontal grooves are shown in the embodiment, the number of horizontal grooves may be a minimum of two.

The present invention provides a manufacturing apparatus structure that uniformly heats the surface of a large substrate exceeding 1 m without substrate deformation. Manufacturing of a solar cell or a flat panel display device using a large substrate is facilitated.

DESCRIPTION OF SYMBOLS 1 Substrate 1a Substrate surface 1b Substrate back surface 1c Heated portion 2 of substrate 2 Gas spraying device 3 Gas beam 4 Gas heating mechanism 5 Coating film 6 Support base 7 Gap 25 Support base 26 Support base 27 Back surface heating mechanism
28 gas heater on electric heater 31 gas blower on the lower side of gas blower 33 on gas heater 34 on gas heater 35 on gas heater 35 on gas heater 37 on gas heater 35 on support base 41 metal plate 42 and 43 transverse groove 44 , 45 longitudinal groove 46, 47 slit groove 48, 49 gas introduction pipe 50, 51 connecting hole 52, 53 side plate 54, 55 heat insulating material 56, 57 metal cover 58, 59, 60 heat insulating material 61 heating wire 62 aperture part

Claims (8)

A substrate heating device having a mechanism for moving a substrate and spraying a heated gas beam having a rectangular or linear cross section on the surface of the substrate to heat the substrate surface, the back surface of the substrate being exposed to the heated gas beam A substrate heating apparatus comprising a back surface heating mechanism for heating the substrate, wherein the substrate passes between the heated gas beam and the back surface heating mechanism. The apparatus according to claim 1, wherein the back surface heating mechanism is sandwiched between the support bases. 3. The apparatus according to claim 1, wherein the back surface heating mechanism is an electric heater. 3. The apparatus according to claim 1, wherein the back surface heating mechanism is a mechanism for blowing a heated gas beam. 5. The apparatus according to claim 1, wherein the gas is a gas containing nitrogen, oxygen, hydrogen, argon, and water. 6. The apparatus according to claim 1, wherein the substrate is made of glass, resin, or metal. A gas flow channel with an inlet and outlet is created from one end of the heated metal heating plate surface to the opposite end, and the metal plate insulated by the heat insulating material is in close contact with the metal heating plate surface The groove forms a flow path that is shielded from the outside, and at least two or more horizontal grooves are formed in the longitudinal direction of the metal plate in the middle of the flow path. The vertical grooves of the horizontal grooves are connected to each other across the wall between the horizontal grooves, and the gas in the horizontal grooves is accelerated by being divided by the vertical grooves and colliding with the wall of the horizontal groove in front of the vertical groove outlet. A heated gas spraying device in which a flow path that merges in the horizontal groove is formed, the gas is heated by passing through the flow path, and the heated gas is blown out in a beam shape. The apparatus according to claim 7, wherein the metal heating plate is heated with a heating wire.