JP2010278076A - Device spraying high temperature gas on low temperature substrate in two steps - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a substrate from being deformed or cracked in the film due to stress of a burnt film, when the substrate is placed on a support stand, and the film on the substrate is burnt so as to form the film by not heating the substrate from the support stand but spraying gas of a high temperature from the substrate. <P>SOLUTION: Burning heat treatment for spraying gas of the high temperature with a fixed heat amount from the support stand of the substrate and for spraying gas with not less than the fixed heat amount is performed. A difference of the heat amount is given by a gas temperature, a gas flow rate, moving speed of the substrate, and a difference between the substrate, and a gas spraying device. Heat burning treatment can also be performed on a bendable sheet-like resin substrate. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  Generally, among devices manufactured by forming a film on a substrate, there are devices that are desired to be processed while the substrate is kept at a low temperature. For example, there is a device using a glass substrate, a resin, a metal sheet substrate, or a silicon substrate after a required film is already formed. As a device using 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 electroluminescence (EL) display device, a solar cell and the like. As a device on a substrate that is inexpensive, easy to handle, and can be wound up, there is a solar cell fabricated on a resin or metal sheet. Recently, there are display devices on a substrate that can be bent and stretched. The thin film used is used as an amorphous film, a crystal film, an insulating film, a conductive film, or a protective film in any device.

An example of a film formed on a substrate held at a low temperature is a plasma-excited amorphous thin film. In this case, since it is non-equilibrium growth (growth that is not reversible reaction), the active composition in the vapor phase causes nucleation and adheres to the substrate, so that the growth proceeds. And the structure is complex and unstable. For this reason, the film contains undesired impurities such as hydrogen and oxygen, easily absorbs moisture, and is inferior in denseness. In order to improve this, there is a technique of annealing with a plasma beam (see Prior Patent Document 1) or laser light. A technique for forming a film having no composition or structural deterioration while maintaining the substrate at a low temperature is required for device production.
An existing manufacturing method for obtaining a dense film includes thermally excited chemical vapor deposition (thermal CVD). In addition, the material is not grown by thermal CVD, but is formed by forming a solution in which the material is dissolved on a substrate by a spin-on method, coating, spraying, or the like, and heating it at 300 to 600 ° C. There is. Examples of the insulating film include spin-on glass and thermosetting resin. Examples of the conductive film include a ZnO film containing impurities Al, a copper (Cu) film, and a silver (Ag) film. As the crystal film, for example, there is CIGS (compound of Cu, In, Ga, Se) which is a compound semiconductor.

  The present invention relates to an improvement in film formation suitable for manufacturing a large-area electronic device, for example, and can be bent like a substrate that cannot be heated to a high temperature, for example, a glass substrate, a substrate that has already completed a wiring process, or a resin or metal sheet A film that can be formed on a substrate only at a high temperature that requires a temperature higher than the temperature of the support that supports the substrate, such as a silicon film, a silicon oxide film, a silicon nitride film, a conductive film, a hard organic film, or a ternary or more The present invention relates to an apparatus for forming a film such as a compound film.

  In chemical vapor deposition (CVD) in which a film is grown on a substrate, the substrate is heated. The deposition gas caused thermal decomposition on the heated substrate, and the generated decomposition active species diffused on the substrate to grow a film on the surface with lateral diffusion. However, when the substrate is a resin or the like, the substrate cannot be heated at a high temperature. Even when a film is formed by coating, the film including the substrate cannot be heated and fired in an electric furnace or the like.

  In order to grow a film while keeping the substrate at a low temperature, active species are generated at a temperature higher than that of the substrate without heating the substrate, and high temperature gas containing the active species is diffused on the substrate placed on the support base. And a film is grown on the substrate. In order to bake the material applied to the substrate such as resin that cannot be heated at high temperature, the surface coating film is heated to release excess solvent by blowing high temperature gas on the substrate placed on the support base, and the structure is dense To stabilize. This is called firing. The problem at this time is shown in FIG. When the high-temperature gas beam 2 generated by the gas heater 3 is sprayed on the substrate surface 1a, the temperature of the substrate 1 varies depending on the degree of adhesion between the support 4 and the substrate back surface 1b, and the dust 5 on the substrate back surface 1b There was a problem affected by air. In the case of vacuum adsorption, the suction hole serves as a gap, and thus becomes a defective conductor of heat. That is, the thermal conductivity distribution depending on the degree of adhesion is transferred. This thermal transfer appears not only as dust, but also as an influence of the surface irregularities when an electrostatic chuck is used. For example, when there is an air gap between the support and the substrate, a 0.1 mm thick polycarbonate substrate is blown with a nitrogen gas beam 2 having a cross-sectional shape of 1 mm × 180 mm at 500 ° C. and 20 standard liters per minute (SLM). Deformed in some part. Thus, in the case of a thermoplastic material such as a resin, thermal transfer remains as a permanent deformation, which is a problem in maintaining flatness. When a film is formed by spraying high-temperature gas, a structure in which the substrate 1 is in close contact with the support table 4 with good reproducibility is required. In order to solve this problem, a viscous material 10 having viscosity, adhesive strength, and heat resistance is inserted between the substrate 1 and the support 4. Although the case where the substrate 1 is a flat surface is shown, the substrate may be a sheet-like substrate that bends. The heat from the substrate back surface 1 b moves to the support base 4 through the viscous material 10. The viscous material 10 is, for example, oil or heat resistant grease. By inserting the viscous material 10, voids created by the dust 5 and voids created by the undulation of the surface shape are filled with the viscous material 10. This eliminates partial non-uniformity in thermal conductivity. Even with an electrostatic chuck, thermal transfer of the surface shape can be prevented by inserting the viscous material 10. When the substrate is bendable, it can be supplied by a roll and collected on the roll, and continuous production of a sheet with a film while keeping the substrate at a low temperature becomes possible. When the substrate is bendable, such as a resin film or a metal sheet, it is easy to attach the viscous material 10 to the back surface of the substrate 1 and to provide a mechanism for collecting and reusing the adhered viscous material. Become.

JP 2006-06130 A

"Development of low-temperature growth technology for polycrystalline SiGe thin film by reactive thermal CVD" Tokyo Institute of Technology Graduate School of Science and Engineering, Image Information Engineering Laboratory Hanna Laboratory [Search June 12, 2008] Internet (URL: http: //www.isl.titech.ac.jp-hanna/cvd.html)

  The problem relates to the improvement of the film quality of the film deposited on the substrate. A film on the substrate can be baked by blowing a gas having a temperature higher than that of the substrate onto the thermoplastic substrate. At this time, film contraction occurs in the vertical and horizontal directions of the film, generating internal stress. This stress causes a problem of warping the substrate or causing cracks. Further, if the surface is baked before the inside, it is difficult for gas to escape from the deep part of the film (shown as outgassing in FIG. 1), and there is a problem that baking in the depth direction of the film becomes insufficient. .

  In order to solve the problem, the amount of heat to be sprayed is set below a certain level so that the film is not completely fired in the first gas spray, and the film is fired by spraying a heat amount exceeding the first time in the second gas spray. This will be described with an apparatus having the configuration shown in FIG. In the configuration of this apparatus, the substrate is moved relative to the two blowing gases. In the first firing, the surface is fired with an amount of heat that still allows the release of gas. Since the film is not completely baked, the contraction ratio of the film in the vertical and horizontal directions is allowed to be different. This is called gentle firing. The gentle firing enables gas release from the deep part of the film, and the contraction stress of the film is relieved by the difference in the amount of deformation in the vertical and horizontal directions of the film. After the first firing in which the film stress is relieved, if a high-temperature gas spray with a larger amount of heat is performed as the second heat treatment, stable bonding of the film structure is promoted. This is called sintering firing. There are four methods for increasing the amount of heat treatment by high temperature gas spraying from the first time to the second time. The first is a method of changing the temperature of the gas used for processing. That is, the temperature of the heater 21 is set lower than the heater 22, and the temperature 1 of the blowing gas 23 is set lower than the temperature 2 of the blowing gas 24. The second is a method of changing the gas flow rate (corresponding to the gas flow rate when the gas blowing section is constant). Even if the temperature 1 and the temperature 2 are the same, a gas blowing with a high flow rate blows a larger amount of heat than a slow blowing. In addition to the difference in the amount of heat that is carried, the difference is also promoted by the difference in the thickness of the stagnant layer that acts as a thermally conductive resistive layer formed on the substrate. The third is a method of changing the relative moving speed of the support base with which the substrate is closely attached and the gas spraying device. In this case, it is possible to perform processing using either a different device or two times using the same device. In FIG. 2, even if the temperatures 1 and 2 and the flow rates 1 and 2 are the same, the moving speed 1 and the second moving speed 2 of the substrate in the first gas blowing heat treatment are changed. The amount of heat irradiated per unit time can be changed by the difference in speed. The fourth is a method of changing the distance (denoted as a gap) from the outlet (orifice) of the heater from which the heated gas blows out to the substrate. The gap 1 is larger than the gap 2. Even if the flow rate of gas to be blown and the temperature of the gas are the same, as the gap increases, the gas that reaches the substrate entrains the surrounding gas and lowers the temperature. At the same time, the gas flow diverges and spreads, reducing the flow velocity. Further, when the speed of collision with the substrate decreases, the stagnant layer as the heat conductive resistance layer also becomes thick. Thus, the difference between gaps 1 and 2 creates a difference in the amount of heat transported to the substrate surface. The mild firing and the sintering firing can be performed in any combination of the four methods.

  The invention according to claim 1 is an apparatus that includes a mechanism for spraying a gas having a temperature higher than that of a substrate placed on a support table from a gas heating device to the surface of the substrate, and forms a film on the surface of the substrate by the spraying mechanism. The film forming apparatus is characterized in that after the gas having a constant temperature is sprayed on the substrate, the preceding gas having a temperature higher than the constant temperature is sprayed.

  The invention according to claim 2 is an apparatus comprising a mechanism for spraying a gas having a temperature higher than that of a substrate placed on a support base from a gas heating device to the surface of the substrate, and forming a film on the surface of the substrate by the spraying mechanism. The film forming apparatus is characterized in that after the gas is sprayed while the substrate is moved at a constant speed, the substrate is moved at a speed slower than the constant speed and the gas is sprayed in the previous period.

  According to a third aspect of the present invention, there is provided an apparatus for forming a film on the surface of a substrate by the spraying mechanism provided with a mechanism for spraying a gas having a temperature higher than that of the substrate placed on a support base from the gas heating device to the surface of the substrate. The film forming apparatus is characterized in that after the gas having a constant flow rate is blown, the gas having a flow rate slower than the constant flow rate is blown.

  According to a fourth aspect of the present invention, there is provided an apparatus for forming a film on the surface of a substrate by the blowing mechanism provided with a mechanism for spraying a gas having a temperature higher than that of a substrate placed on a support base from a gas heating device to the surface of the substrate. The film forming apparatus is characterized in that after the gas is sprayed at a constant distance (gap) from the gas outlet of the gas heating device to the substrate, the preceding gas is sprayed at a distance shorter than the constant distance.

  The invention according to claim 5 is the apparatus according to any one of claims 1 to 4, characterized in that the substrate is a resin or metal sheet containing polycarbonate, PET (polyethylene terephthalate), acrylic, or the like that can be bent.

  The invention according to claim 6 is the apparatus according to any one of claims 1 to 5, wherein a rotating drum is the support base.

  A seventh aspect of the present invention is the apparatus according to any one of the first to sixth aspects, wherein a plurality of the gas blowing mechanisms are provided.

  The invention according to claim 8 is the apparatus according to claims 5 and 7, wherein the bendable resin or metal sheet substrate is supplied from a roll, wound up and collected by the roll.

According to the inventions according to claims 1 to 4, when the film is heat-treated by spraying a gas at a temperature higher than that of the substrate with two different amounts of heat onto the substrate placed on the support table, the subsequent processing than the preceding processing. By performing with high heat quantity, the film can be stably fired on the substrate kept at a low temperature. The two-stage high-temperature gas heat treatment can relieve the stress of the film, which could not be avoided by one firing. As a result, cracks in the film can be prevented and the warpage of the substrate can be reduced.
According to the inventions according to claims 5 to 8, it is possible to use a resin film such as polycarbonate, PET (polyethylene terephthalate), or acrylic as a substrate which can be bent. A metal sheet may be used as the substrate. These bendable materials are light and easy to carry. If a film can be grown on such a substrate, the solar cell and the flat display device become lighter, and the transportation and installation become easier, and the production, supply, installation, and operation can be performed at a low cost. Therefore, the industrial value is high.

  It is possible to select a rotating drum as the support base 4 because it is a bendable substrate. When the substrate is in close contact with the drum and the drum rotates, the substrate can be moved by the rotation of the drum. The substrate moving speed can be controlled by the number of revolutions of the drum. Further, there is an advantage that the apparatus can be made smaller than the mechanism for moving the flat substrate support in the horizontal direction. When the rotating drum on the side not in contact with the substrate is brought into contact with the liquid medium, the substrate temperature can be continuously controlled by the medium temperature.

  According to the invention which concerns on Claim 7, the process by the gas spraying mechanism of different temperature or a different flow velocity and a different gap can be continuously performed by one apparatus. Whether it is a flat substrate or a bendable substrate, there is an advantage that the substrate can be continuously moved at a constant speed, and two different firing processes can be performed.

  According to the eighth aspect of the present invention, the bendable resin or metal sheet substrate can be supplied from a roll and wound on the roll. This allows for continuous film formation and high productivity.

FIG. 1 is a schematic diagram showing a problem of a film forming apparatus that blows a gas having a temperature higher than that of a substrate. FIG. 2 is a schematic diagram of the basic structure of an apparatus for solving the problems. Deterioration of the fired film is prevented by making the amount of heat of the preceding gas blowing process smaller than that of the subsequent process. FIG. 3 is a schematic view of an embodiment of a gas spraying apparatus using a sheet substrate and a rotating drum support. A bent substrate is wound around a drum and rotated. FIG. 4 is a schematic view of an embodiment of an apparatus for supplying and recovering a sheet substrate from a roll. This is an apparatus provided with two high-temperature gas spraying apparatuses. A viscous material is uniformly attached to the back surface of the sheet substrate using a squeegee, wiped with a squeegee after high-temperature gas treatment, and completely removed with a rotating brush soaked with a solvent. FIG. 5 is a schematic diagram of the prior art of an apparatus for heat-treating an amorphous film on a substrate with plasma.

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 is shown in FIG. A polycarbonate substrate 31 bent on the rotation support base 34 is in close contact with a grease 30 which is a viscous material. The rotation support base 34 is made of stainless steel. It is controlled by a stepping motor and rotates. The rotational speed is 300 mm / min as the moving speed of the surface. In this embodiment, a hot gas spraying device 32 is placed on a rotating support base. Nitrogen gas is introduced and heated by the gas heater 33. The gas is heated through two passages to create a gas beam 35 and a gas beam 36 that are blown into a beam. The gas heater 33 is made of carbon, and the surface in contact with the gas is coated with silicon carbide. The gas heater may be ceramics. A metal may be used at a low temperature. Since carbon is less deformed, it is suitable for producing a high-temperature gas. The beam-like gas exits from the outlet (orifice) of the gas heater having a width of 1 mm and a depth of 180 mm and strikes the surface of the substrate 31. Since the support base rotates to the left, the right gas beam 35 blows first. The gas heater is 550 ° C. The nitrogen gas beam 35 is 3 SLM (standard liters / minute), and the coating film on the substrate 31 (for example, coated organic glass that hardens when fired) is gently fired. The nitrogen gas beam 36 is 15 SLM, hits the polycarbonate substrate 31 at a high speed, and the coating film is sintered and fired. It was confirmed that the infrared absorption peak corresponding to the OH group was decreased from that before the baking treatment, and the baking was advanced. When the hardness of the fired film was measured by a pencil scratching method, scratches were not recognized with the naked eye with a pencil of 4H to 6H. Scratches were observed with pencils of higher hardness.
FIG. 4 shows a second embodiment. In this embodiment, two gas spraying devices 431 and 432 are provided. The distance (gap) between the spraying device 431 and the bendable polycarbonate substrate 41 is 20 mm. The spray device 432 is 10 mm larger than that of the device 431. Although the internal structure of the apparatus is not shown in the figure, two gas beams are sprayed as in FIG. The two nitrogen beams of the apparatus 431 are 3 SLM at the same flow rate, and the heating temperature is 350 ° C. The two nitrogen beams of the device 432 are 20 SLM at the same flow rate, and the heating temperature is 550 ° C.

  A polycarbonate sheet substrate 41 coated with an organic glass film that hardens when fired is supplied from a sheet substrate roller 42. The sheet substrate 41 is wound in close contact with the drum-shaped rotation support base 44. The other side of the rotation support base 44 is attached to a viscous material applicator 45 in which grease 40 is stored as the viscous material 10. The grease 40 adheres due to the rotation of the support base. The grease is attached to a certain amount of thickness with a rubber squeegee 46. While rotating the sheet substrate at a surface moving speed of 30 cm / min, nitrogen gas heated to 350 ° C. is blown by the gas blowing device 431 at a flow rate of 3 SLM. Next, nitrogen gas heated to 550 ° C. is blown at a flow rate of 20 SLM by a gas blowing device 432. The sprayed gas has a beam shape with a cross section of 1 mm × 180 mm. The grease 40 is collected by the squeegee 47 and returned to the applicator 45 again. The viscous material wiping device 49 storing the wiping liquid 48 is provided with a rotary wiping brush 50 and rotates while the wiping liquid 48 is bathed on the substrate sheet 41. In the case of grease, the wiping liquid 48 may be, for example, ethyl alcohol. The brush may be a sponge. In order to dry the alcohol, warm air is applied by a warm air dryer 51. Although the squeegee is shown as one stage, it may be any number of stages. There may be a plurality of viscous material wipers 49. The clean sheet substrate 41 after wiping off the viscous material is wound around the collection roller 52. In this manner, it was confirmed that the infrared absorption peak corresponding to the OH group of the coating film after the sintering and firing was reduced from that before the firing treatment, and the sintering and firing proceeded. When the hardness of the film was measured by a pencil scratching method, scratches were not recognized with the naked eye with pencils of 4H to 6H. Scratches were observed with pencils of higher hardness.

Here, the polycarbonate resin sheet substrate 41 is given as the bendable sheet substrate, but a resin film such as acrylic or PET (polyethylene terephthalate) may be used as the substrate. Further, a metal sheet of stainless steel or aluminum may be used. Although the grease 40 is given as the viscous material 10, oil, water, or wax may be used. Alternatively, it may be a film material that is preliminarily attached to the sheet substrate and softens or liquefies when high-temperature gas is sprayed.

The present invention facilitates the manufacture of solar cells and flat panel display devices that use large substrates that form films at higher temperatures than the substrate.

DESCRIPTION OF SYMBOLS 1 Substrate 1a Substrate surface 1b Substrate back surface 2 High temperature gas 3 Gas heater 4 Support stand 5 Garbage 10 Viscous material 21 Heater 1
22 Heater 2
23 Blowing gas 1
24 Blowing gas 2
30 Grease 31 Polycarbonate substrate 32 High-temperature gas spraying device 33 Gas heater 34 Rotating support base 35 Gas beam 1
36 Gas Beam 2
40 Grease 41 Sheet substrate 42 Feed roller 431 Gas spraying device 1
432 Gas spraying device 2
44 Rotating Support Base 45 Viscous Material Adhering Device 46 Shikiji 47 Squeegee 48 Wiping Liquid 49 Viscous Material Wiping Device 50 Rotating Wiping Brush 51 Dryer 52 Recovery Roller

Claims (8)

  A device for forming a film on the surface of the substrate by means of the blowing mechanism, the device being provided with a mechanism for spraying a gas having a temperature higher than that of the substrate placed on a support base onto the substrate surface from a gas heating device, A film forming apparatus characterized by spraying the gas at a temperature higher than the certain temperature after spraying the gas.   A device comprising a mechanism for spraying a gas at a temperature higher than that of a substrate placed on a support table from a gas heating device onto the surface of the substrate, and forming a film on the surface of the substrate by the spraying mechanism, wherein the substrate is moved at a constant speed. A film forming apparatus, wherein after spraying the gas while moving, the substrate is moved at a speed slower than the constant speed to spray the gas in the previous period.   A device for forming a film on the surface of the substrate by the blowing mechanism, the device having a mechanism for spraying a gas having a temperature higher than that of the substrate placed on a support table from a gas heating device to the surface of the substrate; A film forming apparatus, wherein after spraying, a previous gas having a flow rate slower than the constant flow rate is sprayed.   A device comprising a mechanism for spraying a gas at a temperature higher than that of a substrate placed on a support base from a gas heating device onto the surface of the substrate, and forming a film on the surface of the substrate by the spraying mechanism, the gas of the gas heating device A film forming apparatus, wherein the gas is sprayed at a distance shorter than the predetermined distance after the gas is sprayed at a constant distance from the outlet to the substrate.   5. The apparatus according to claim 1, wherein the substrate is a bendable polycarbonate, PET (polyethylene terephthalate), a resin containing acrylic, or a metal sheet.   6. A device according to claim 1, wherein the rotating drum is the support base.   7. The apparatus according to claim 1, wherein a plurality of the gas blowing mechanisms are provided.   The apparatus according to claim 5 or 7, wherein the bendable resin or metal sheet substrate is supplied from a roll, wound around the roll and collected.