JP2012009885A - Lighting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heating unit that effectively uses radiation from a heat transfer plate of the heating unit including a light source and the heat transfer plate.SOLUTION: In the heating unit that irradiates the heat transfer plate by a halogen lamp and heats a body to be heated with heat transferred from the irradiated heat transfer plate, the heat transfer plate comprises a holder which has optical transparency and a heat transfer body which is provided to the holder on the side of the body to be heated, and absorbs light transmitted through the holder to generate heat. A light source-side surface of the holder is processed into a mirror surface, and a surface roughness Ra (μm) of the surface processed into a mirror surface has a value smaller than a wavelength of 2.5 (μm) of the radiant light radiated by the heat transfer body.

Description

  The present invention relates to a light irradiation type heating unit for heating a substrate such as a semiconductor wafer or a display panel, or for heating glass or plastic, and in particular, irradiates a heat transfer plate with light from a light source. The present invention relates to a heating unit that heats an object to be heated by radiation from the heat transfer plate.

  Conventionally, various processes such as annealing, film formation, and sputtering are used in processes such as processing semiconductor wafers. In addition to wafer processing, heat treatment is also performed in a glass substrate processing process for manufacturing a display.

  As a heating unit that performs such heat treatment, a heating source (a lamp in a light irradiation type heating unit) and a work piece are used to heat the work surface so that the temperature distribution on the work surface becomes uniform. A member provided with a so-called soaking plate is known. As the soaking plate, a metal or carbon plate having good thermal conductivity is used. Japanese Patent Application Laid-Open No. 7-172996 discloses one using a stainless steel plate as a soaking plate.

By the way, in the heating unit using this heat equalizing plate (heat transfer plate), a heat equalizing plate having high thermal conductivity and a large heat capacity is used in consideration of the influence of disturbance, but on the other hand, it is a heating source. The response to changes in lamp output becomes dull, and temperature control in a short time becomes difficult.
From such a viewpoint, it is desirable that the heat equalizing plate used in the heating unit has a small heat capacity, and a heat equalizing plate that is as thin as possible is required.

  However, if a thin heat equalizing plate, for example, a metal heat equalizing plate having a thickness of 3 mm is used, the heat capacity is small, so that thermal distortion occurs due to the temperature difference between the two surfaces of the heat equalizing plate and warpage (deformation) occurs. There is a defect that occurs.

  In addition, when a carbon plate is used as the soaking plate, warpage (deformation) due to residual strain during processing may occur during cooling after molding at high temperature. For example, a carbon soaking plate having a thickness of 3 mm warps about 1 mm for a length of 300 mm.

  If there is such warpage (deformation), the distance between the heat equalizing plate and the work to be heated is not constant, and the heat from the heat equalizing plate is transferred to the work non-uniformly. There is a problem that overheating is not uniform.

  In order to solve these problems of the heating unit using the heat equalizing plate, the inventors filed Japanese Patent Application No. 2003-364398 and Japanese Patent Application No. 2004-40744 to hold the heat transfer plate with light transmittance. A heating unit is proposed that includes a body and a heat transfer body that is provided on the surface of the holding body and generates heat by absorbing light from a light source.

  Thus, a heat transfer unit that suppresses deformation such as warpage of the heat transfer body by providing a thin heat transfer body to improve heat responsiveness and providing the heat transfer body on a light-transmissive holding body is provided. It is something to be done.

Japanese Patent Laid-Open No. 7-172996

The above application has proposed a heating unit provided with a heat transfer plate having good heat responsiveness and no deformation of the heat transfer body, but the present invention relates to an improvement of these proposed heating units.
That is, in these heating units, the radiation from the heat transfer body is only used from the surface, that is, the surface to be heated to the object to be heated, and the back side, that is, the light source (lamp). Since the radiation from the side surface side is not used, the energy of the light source is not used effectively.

  Therefore, an object of the present invention is to provide a heating unit that can effectively use the energy of irradiation light from a light source by increasing radiation from a heat transfer body to an object to be heated. .

  Means for solving the problems of the present invention is a heating unit that irradiates a heat transfer plate with a halogen lamp and heats an object to be heated by heat transfer from the irradiated heat transfer plate. A holding body having light permeability and a heat transfer body that is provided on the heated object side of the holding body and absorbs light transmitted through the holding body to generate heat, and the light source side surface of the holding body has a mirror surface The surface roughness Ra (μm) of the processed and mirror-finished surface is a value smaller than the wavelength 2.5 (μm) of the radiated light radiated from the heat transfer body.

According to the present invention, by mirror-treating the lower surface of the holding body, at least a part of the radiation from the heat transfer plate to the light source side is reflected and returned to the heat transfer body side and reheated to be heated. The amount of radiation to the object can be increased.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a detailed partial view of Embodiment 1 of the present invention. (A) (B) (C) The partial figure of embodiment of Example 1 of this invention. The detailed fragmentary diagram of Example 2 of this invention. FIG. 5 is a detailed partial view of Embodiment 3 of the present invention. Spectrum of light source (halogen lamp). The emission spectrum of the heat transfer body. (A) (B) The detail fragmentary figure of other embodiment of Example 3. FIG.

An embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a cross-sectional view illustrating a configuration of a heating unit according to Embodiment 1 of the present invention.
In the figure, a plurality of light sources 1 are provided in the unit body 5. The light source 1 is, for example, an incandescent lamp such as a halogen lamp, a discharge lamp such as a xenon lamp or a metal halide lamp. Above the light source 1 of the main body 5, a holding body 2 that transmits light from the light source 1 and an upper surface thereof, which absorbs light from the light source 1 that has transmitted through the holding body 2 and generates heat. A heat transfer plate 4 comprising a heat body 3 is provided. A heated object 6 such as a semiconductor wafer or a glass substrate is disposed above the heat transfer plate 4.

The holding body 2 is made of glass such as quartz glass, borosilicate glass, sintered quartz glass, and aluminosilicate glass, glass ceramic, translucent alumina, sapphire, and the like. Since these materials have a smaller coefficient of thermal expansion than metals and carbon graphite, they are less likely to deform, are chemically robust and have excellent heat resistance, transmit light in the ultraviolet region or visible region, and generate less heat.

The heat transfer body 3 is made of diamond-like carbon (DLC), metal oxide such as chromium oxide, nitride such as aluminum nitride or boron nitride, silicide such as silicon carbide or molybdenum silicide, and the like. Or it consists of various glass and various ceramics containing molybdenum, chromium, carbon, etc. These materials are chemically robust and excellent in heat resistance, generate heat by blocking light from the ultraviolet region to the visible region, and have high thermal conductivity.

  Formation (coating, etc.) of the heat transfer body 3 on the holding body 2 is performed by CVD in the case of diamond-like carbon (DLC), and in the case of metal oxide, nitride, or silicon carbide, coating / firing or plasma. It is formed by thermal spraying, printing, etc., and in the case of silicide, it is formed by heating after CVD, sputtering or vapor deposition. When CVD, coating, thermal spraying, printing, sputtering, and vapor deposition are used, the heat transfer body 3 can be formed by controlling the thickness of the heat transfer body 3 to a desired thickness even if the holding body 2 has some unevenness.

  FIG. 2 is a detailed partial view, wherein the upper surface of the heat transfer body 3, that is, the surface 3A on the heated object 6 side is processed with a diffusion surface. In general, the amount of radiation from an object is proportional to the surface area, but the surface area of the surface 3A is increased from the back surface, that is, the surface 3B on the light source 1 side by the diffusion surface processing. As a result, the radiation from the heat transfer body 3 heated by the light transmitted from the light source 1 through the holding body 2 is lower, that is, higher than the radiation amount toward the light source 1 side, that is, toward the heated object 6 side. The amount of radiation increases. Therefore, the irradiation energy from the light source 1 can be used more effectively.

  The diffusion surface processing of the upper surface 3A of the heat transfer body 3 may be any method that forms irregularities on the surface by mechanical rough polishing processing, frost processing, cutting processing, chemical etching processing, or the like. And as the uneven | corrugated shape, as shown in FIG. 3, various shapes may be sufficient. 3A shows a large number of mountain-shaped convex portions 7A, FIG. 3B shows a continuous convex portion 7B, and FIG. 3C shows a large number of concave portions 7C. It is a thing.

FIG. 4 is a detailed partial view of a second embodiment in which the lower surface of the holding body 2, that is, the surface 2B on the light source 1 side is mirror-finished. The surface roughness (Ra) of the mirror-finished surface 2B is set to a value smaller than the wavelength λ of the radiation light. By doing this, among the radiant light radiated from the heated heat transfer body 3, the radiant light having a certain incident angle or more is totally reflected by the mirror surface and returned to the heat transfer body 3 direction. Reheat 3. And it is radiated | emitted to the to-be-heated material 6 from the upper surface 3A.
Thereby, at least a part of the radiation light downward from the lower surface 3 </ b> B of the heat transfer body 3 can be effectively used by returning it to the heated object 6 side.

FIG. 5 is a detailed partial view of another embodiment 3, in which a radiation reflection layer 10 is provided below the holder 2 of the heat transfer plate 4, that is, below the light source 1 side. The radiation reflection layer 10 is formed of a multilayer film reflection layer that transmits light from the light source 1 and reflects radiation light from the heat transfer body 3. When the light source 1 is a halogen lamp, the incident light from the light source 1 emits less in the wavelength region of 2.5 μm or more when the color temperature of the tungsten filament exceeds 2200 K as shown in FIG. On the other hand, the radiation from the heat transfer body 3 has a spectrum in a wavelength region of 2.5 μm or more as shown in FIG.
Therefore, the radiation reflection layer 10 has such characteristics that it transmits light having a wavelength of 2.0 to 2.5 μm or less and reflects light having a wavelength of more than this region in consideration of both of these spectra. Any material can be used as long as it satisfies such conditions, and examples of the constituent material for the multilayer film include low refractive materials such as Al ₂ O ₃ , SiO, SiO ₂ , MgF ₂ , and AlF ₃ , TiO ₂ , Ta ₂ O ₅ , It is obtained by a combination of materials selected from high refractive materials such as Si, ZrO ₂ and Y ₂ O ₃ .

  In the third embodiment, as in the second embodiment of FIG. 4, the radiation light directed downward from the heated heat transfer body 3 is returned to the heat transfer body 3 by the radiation reflection layer 10 and reheated. . Thus, the radiant light from the heat transfer body 3 heated by the light source 1 can be used effectively.

  The transmission wavelength characteristics of the radiation reflection layer 10 have been described in the spectrum when a halogen lamp is used as the light source 1. However, even in the case of other lamps such as a xenon lamp and a metal halide lamp, 2.0 to If it is a characteristic that transmits light having a wavelength of 2.5 μm or less, most of the light emitted from these lamps is transmitted, and there is no practical problem.

By the way, in the said Example 3, although what has arrange | positioned the radiation reflection layer 10 under the heat exchanger plate 4 was shown, it is not restricted to this.
FIG. 8 shows another embodiment, and in the structure shown in FIG. 8A, the radiation reflection layer 10 is provided on the upper surface of the holding body 2, that is, between the holding body 2 and the heat transfer body 3.
8B, the radiation reflection layer 10 is provided on the lower surface of the holding body 2 of the heat transfer plate 4. As shown in FIG.
Any of these radiation reflecting layers 10 shown in FIG. 8 is made of a multilayer film similar to that shown in FIG.

It will be easily understood that these radiation reflecting layers 10 have the same function as the radiation reflecting layer 10 of FIG.
That is, the radiation reflection layer 10 may be any layer as long as it returns radiation from the heat transfer body 3 toward the light source 1 to the heat transfer body 3 again, and may be provided between the heat transfer body 3 and the light source 1.

In addition, in the Example of the heat exchanger plate of this invention, although the heat exchanger has demonstrated the structure formed in the upper surface of a holding body, as shown in Japanese Patent Application No. 2004-40744, it holds with a heat exchanger. The structure which provided the gap | interval between the bodies may be sufficient. In this configuration, it is preferable that the upper surface of the holder has a function of reflecting radiation.

Further, in each of the above embodiments, the heating unit is irradiated upward, and the article 6 to be heated is disposed above the heating unit. However, the present invention is not limited to this. It may be in any direction such as downward or sideward, and the object to be heated 6 only needs to be disposed opposite to the heat transfer plate 4 of the heating unit.

  As described above, in the present invention, in the heating unit provided with the light source and the heat transfer plate, the heat transfer plate is constituted by the holding body that transmits the light source light and the heat transfer body provided on the upper surface thereof, From the heat transfer body heated by the light source by processing the diffusion surface on the upper surface of the heat transfer body, mirror-finishing the lower surface of the holding body, or providing a radiation reflection layer between the heat transfer body and the light source Since the radiant light radiated to the object to be heated can be increased, an excellent effect that the heat treatment can be performed by effectively using the irradiation energy from the light source is achieved.

DESCRIPTION OF SYMBOLS 1 Light source 2 Holding body 3 Heat transfer body 4 Heat transfer plate 5 Unit main body 6 Heated object 10 Radiation reflection layer

Claims (1)

In a heating unit that irradiates a heat transfer plate with a halogen lamp and heats an object to be heated by heat transfer from the irradiated heat transfer plate,
The heat transfer plate is composed of a holder having light permeability, and a heat transfer body that is provided on the heated object side of the holder and absorbs light transmitted through the holder to generate heat.
The light source side surface of the holding body is mirror-finished,
The heating unit characterized in that the surface roughness Ra (μm) of the mirror-finished surface is smaller than the wavelength 2.5 (μm) of the radiated light radiated from the heat transfer body.

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