JPH0722261U - Contact type uniform heating device - Google Patents

Abstract

(57) [Summary] [Purpose] To obtain a uniform temperature distribution with a simple configuration. [Structure] A sealed space portion 2 is provided corresponding to substantially the entire heating surface 1 on which an LCD glass substrate 100 is placed, and a heat transfer liquid contained in a liquid reservoir portion 2a located in a central portion below the space portion 2. 3 and an electric heater 4 for heating the heat transfer liquid 3 in the liquid reservoir 2a. A fin 6 fixed to the heating surface 1 and a bottom plate 5 forming the space 2 by brazing or the like is provided in the space 2, and the inside thereof is filled with a saturated gas of the heat transfer medium 3 corresponding to the temperature thereof. Has been done. A heating current is sent from the power source 7 to the electric heater 4 via the operating end 8, and the evaporation amount of the heat transfer liquid 2 is controlled by the temperature sensor 9 and the temperature controller 10. [Effect] Even if the amount of heat radiated from the heating surface changes,
The temperature of the heating surface can be maintained extremely accurately and uniformly. In addition, it does not require adjustment and is easy to handle.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a contact heating device for heating an object to be heated by placing it on a heating surface and contacting it.

For example, in a manufacturing process of a liquid crystal display (LCD), a resist or the like for forming an alignment film on a glass substrate, forming a pattern and forming a driving device is heated at a high temperature after applying a material on the glass substrate. Drying and baking are performed, but if this is performed by hot air drying, the surface may dry quickly, and bubbles of solvent vapor may remain inside the delayed drying, resulting in poor quality. There is also the problem that wind ripples remain. For this reason, a hot plate is used as a heating source for the LCD glass substrate baking apparatus so that the LCD glass substrate can be dried in a windless state. Also, in the manufacturing of semiconductor devices, in the tests that are performed at high temperature among the operation tests, the device is preheated to the test temperature and sent to the test unit. A hot plate or heat block is used as the heat source for the high temperature handler. The contact heating device of the present invention is used for such a hot plate or heat block, for example. Furthermore, it is also used for hot plates and the like other than industrial applications such as cooking.

[0003]

[Prior art]

 Conventionally, as a contact heating device such as a hot plate or a heat block, a device configured by attaching an electric heater as a heating element to a metal having good thermal conductivity such as aluminum or its alloy has been used. As a method for attaching this electric heater, there are adopted a mechanical pressure welding method in which a thin heater is sandwiched between metal plates and a method in which a sheathed heater is cast in metal. The surface temperature distribution is the most important factor in the performance of hot plates and heat blocks, but in the pressure contact type heater as described above, there are variations in the pressure contact state, so the entire surface is heated with a uniform capacity. A good temperature distribution cannot be obtained even when heated in a vessel. Further, in such a contact heating device, since the heat dissipation is larger in the peripheral part than in the central part, if the supplied heat amount is the same, a temperature difference occurs between them.

As a contact heating device that solves such a problem, a heating section is divided into a large number, and a small-capacity heater and a temperature sensor, which are divided into each section, are provided, and each sensor is provided. There is also a device that connects to as many temperature controllers as there are compartments and controls the temperature of each heater individually for each compartment. In this device, the temperature setting values of many temperature controllers are basically the same, but they are finely adjusted while actually measuring the temperature distribution. In addition, there is also a device in which one section that can represent the whole is selected, a temperature sensor is attached to it, and it is connected to a temperature controller to control all sections. In this device, the capacity of the heater provided in each section can be changed by individual voltage adjustment and phase control, and each capacity is adjusted while actually measuring the temperature distribution so that the temperature distribution is optimized. Was set to capacity.

However, if a large number of temperature controllers and capacity controllers of heaters are provided in this way, the apparatus becomes complicated and the cost is high, and it takes a long time to adjust the temperature distribution. In addition, even if the heating capacity is adjusted for each section, the temperature distribution during adjustment may not be reproduced due to changes in the state of wind that flows on the surface of the hot plate or heat block, or changes in air temperature. Then, when the heater was replaced due to disconnection, etc., the temperature distribution was measured each time and it was necessary to readjust the capacity. Furthermore, in the case of a heater failure such as wire breakage or poor insulation, the cast-in type had to be replaced in its entirety, which was a large expense.

[0006]

[Problems to be solved by the device]

 The present invention solves the above problems in the prior art, has a simple structure, does not require special adjustment, and has a highly accurate and uniform temperature distribution even when the surface wind conditions and temperature change. It is an object of the present invention to provide a contact heating device having good performance and good operability.

[0007]

In order to solve the above problems, the present invention provides a contact heating device for heating an object to be heated by placing the object on a heating surface and bringing the object into contact therewith. In the above, there is provided a space portion which is provided so as to correspond to substantially the entire area of the heating surface and which is filled with a heat transfer medium and its saturated gas, and a heating means for heating the heat transfer medium. In addition to the above, the invention of claim 2 is characterized in that the heating surface is a flat surface having a considerable spread, and the invention of claim 3 is characterized in that in addition to the features of the invention of claim 1, The heating surface is an elongated surface.

[0008]

[Action]

 According to the invention of claim 1, since the heat transfer liquid and its saturated gas are contained in the closed space, when the heat transfer liquid is heated by the heating means, its temperature rises and at the same time, a part thereof. Are vaporized at the same temperature, and the pressure in the space rises. Such changes maintain the relationship between saturation temperature and saturation pressure. The vaporized saturated gas immediately spreads inside the space. Since this space is provided corresponding to substantially the entire heating surface on which the object to be heated is placed, the gas filled in the space gives heat to the substantially entire heating surface. In this case, since this gas is a saturated gas, heat is applied to the heating surface by condensing on the wall surface in the space, so the heat transfer coefficient is extremely good. Then, since the state change in which the saturated gas condenses occurs at a constant temperature, the saturated gas gives only large latent heat to the heating surface at a constant temperature, and the heating surface is heated uniformly and becomes constant. There is no temperature variation as it reaches temperature. Further, since the heating means evaporates the heat transfer liquid, the saturated gas is always supplied, so that even if the heat radiation is large, for example, in the portion where the object to be heated is placed or the peripheral portion of the heating surface, By increasing the heat absorption capacity of a part, more gas is supplied and liquefied in the space corresponding to that part than in other parts, and the partial temperature drop on the heating surface is suppressed by the inevitable increase in the amount of heat supply. To be done. That is, the condensed droplets drop on the wall surface in the space, and the saturated gas is continuously and freely supplied as needed, so that the uniformity of the heating surface temperature is maintained as a whole. For example, in heating with a heating wire or the like, since the amount of heat supplied is constant, such an action does not occur, and the temperature significantly decreases at the peripheral portion of the heating surface and the like.

According to the second aspect of the invention, since the heating surface is a plane having a considerable spread, the contact heating device can be used as, for example, a hot plate. When heating the hot plate, for example, a structure in which a plurality of heat pipes are installed in parallel under the heating surface to uniformly heat with an electric heater etc. and to prevent local surface temperature variations However, in this configuration, there is a temperature difference between the part with the heat pipe and the part between them. Further, when the heat pipe operates, heat absorption and heat dissipation occur on the evaporation side and the condensation side, respectively, so a certain temperature difference is required between them, and it is possible to avoid a certain temperature difference on the surface. Absent. However, in the present proposal, since the space is provided corresponding to the heating surface and the saturated gas is freely supplied to this space, even if the heating surface has a two-dimensional spread, There is no temperature difference in the direction, and the present invention is particularly effective for such a heating surface.

The invention of claim 3 is intended for the case where the heating surface is elongated. The contact heating device having such a heating surface is used, for example, as a heat block for heating a semiconductor element. In this case, when the saturated gas gives heat to the heating surface and condenses, the liquid needs to be returned to the position where it is heated and evaporated again by the heating means, but when the length of the heat block is particularly long, On the other hand, the liquid does not return well on the heated surface, and the heat transport capacity is slightly reduced (10 to 30%). This problem can be solved by designing with a reduction in mind or by inclining the heating surface. If the heating surface is inclined, there is an effect that the object to be heated can be heated while being dropped by its own weight. When the heating surface is horizontal, an object to be heated such as a semiconductor element is forcibly fed by mechanical force.

[0011]

【Example】

 FIG. 1 shows a cross-sectional structure of a hot plate as a contact heating apparatus of the embodiment. The hot plate is a device that heats an object to be heated, for example, by placing an LCD glass substrate 100 on the heating surface 1 and bringing it into contact with the heating surface 1. The hot plate is provided in substantially the entire area of the heating surface 1 and is a sealed space. 2, a heat transfer medium 3 contained in a liquid reservoir 2a located in the center below the heating medium, and a heating means provided outside the liquid reservoir 2a so as to contact the heat transfer medium 3 to heat the heat transfer medium 3. And an electric heater 4 as

The space 2 is filled with a saturated gas of the heat transfer liquid 3 corresponding to the temperature. In this embodiment, the heating surface 1 is formed in a flat shape. However, it is naturally possible to make it concave or inclined. Further, fins 6 fixed to the heating surface 1 and the bottom plate 5 forming the space 2 by brazing or the like are entirely provided in the space 2 (in FIG. 1 (a), an intermediate portion is shown). Omitted). The fins 6 are heat transfer surfaces that are expanded to increase the amount of heat transfer from the space 2 to the heating surface 1, and the strength that prevents the heating surface 1 from deforming due to internal pressure and maintains its flatness. Become a member. The fin 6 is provided with a notch 6a to improve the flow of gas between the fins.

There are many kinds of heat transfer liquid 3 that can be used in the contact heating device, and which one is used is selected according to the temperature range of the heating surface which is determined corresponding to the object to be heated. . For example, if it is used in a pressure range from negative pressure to 10 to 15 kg / cm ² , CFC R114, CFC R11, CFC R113 and water are 80 ° C, 110 ° C, 140 ° C and 200 ° C, respectively. It can be operated up to moderate temperatures. In the manufacturing process of the LCD glass substrate, it is appropriate to set the temperature of the heating surface 1 to about 80 to 120 ° C. Therefore, as the heat transfer medium, for example, Freon R113 or water can be used. As the heat transfer medium in the high temperature range, for example, those such as naphthalene and sodium metal that are solid at room temperature and liquefy when the temperature rises and vaporize when heat is further applied are used. Naphthalene is operated in a temperature range of about 200 ° C to 350 ° C.

A heating current is sent to the electric heater 4 from the electric power source 7 via the operating end 8. In this embodiment, the temperature sensor 9 and the temperature controller 10 are provided, the detected temperature of the heating surface 1 is compared with the set value in the temperature controller 10, and the operation amount according to the deviation is output. The current sent from the power supply 7 is adjusted so that the temperature of the heating surface 1 reaches the desired temperature set at the operating end 8, and the evaporation amount of the heat transfer medium 3 is controlled. The temperature sensor 9 is attached so as not to impede the flatness of the heating surface. The hot plate has its entire circumference excluding its heating surface kept warm by an insulating material (not shown) to reduce heat dissipation and reduce the amount of electricity.

The hot plate is operated as follows. When the temperature of the heating surface 1 is set to a desired temperature at the operating end 8 and the power source 7 is turned on, an electric current is passed through the electric heater 4 to heat the heating medium liquid 3 stored in the liquid reservoir 2a, As the temperature rises, the amount of vaporization increases, the amount of gas in the space 2 increases, and its pressure and temperature rise. The pressure and the temperature change while maintaining the relationship between the saturation pressure and the saturation temperature based on the characteristics of the heat transfer medium 3. Further, since the gas inside is a gas at the saturation temperature, it liquefies when the temperature drops even a little, so that the temperature of the gas is the same anywhere in the space 2. When the gas spreads in the space 2 through the spaces between the fins 6 and through the notches 6a and touches the fins 6 and the back surface side of the heating surface 1 which is not insulated, heat is taken away at the contact portions and condensed. Liquefy. At this time, latent heat of condensation is applied to the heating surface 1 from the contact portion. On the other hand, the liquid droplets of the liquefied heat transfer medium drop or flow down from the heat transfer surface, are collected in the liquid reservoir 2a along the inclined bottom plate 5, and are heated and evaporated again. Since the gas having the same temperature and the same latent heat in the space has such a function, the heating surface 1 is uniformly heated over the entire area. In this case, the peripheral portion of the heating surface 1 dissipates a large amount of heat, so the temperature tends to drop, but if the temperature drops, the endothermic ability of this part increases, and the amount of gas condensed inside increases. As a result, the same temperature is maintained in the peripheral area as in the central area.

When the temperature of the heating surface 1 reaches the set temperature, the current sent to the electric heater 4 decreases, the vaporization amount of the heating medium liquid 1 decreases, and the heating surface 1 is maintained at the set temperature. When the object to be heated is placed on the heating surface in this state, heat transfer occurs during this time, and the temperature of that part of the heating surface decreases, but the evaporation amount of the heat transfer liquid 1 is adjusted so that this temperature becomes the set temperature. Increase, the amount of gas supplied to the part where the temperature has dropped increases and the temperature of that part rises. In this way, a generally uniform temperature is maintained throughout. In the conventional hot plate, the variation in temperature increases as the size increases and the set temperature increases, and the value is ± 5 ° C to ± 10 ° C. Irrespective of the size and temperature, the temperature variation could be easily controlled to about ± 1 ° C to ± 2 ° C.

In the above, the case where the hot plate has a rectangular shape has been shown, but it goes without saying that it may have another shape such as a circle. Further, although the fin 6 is provided in the space portion 2, it may be omitted. Further, the space portion 2 may be provided so as to communicate with the entire heating surface 1 substantially in its entirety, and for example, after a number of inclined holes are drilled from the periphery of an integral plate material, the space portion 2 is exposed to the outside. It may be formed by a method of closing the opening of the.

FIG. 2 shows the structure of a heat block as another embodiment of the contact heating device. The heat block is a device that heats an object to be heated, for example, by placing semiconductor elements 101 aligned on the heating surface 1 and bringing the semiconductor element 101 into contact with the heating surface 1 to cover substantially the entire area of the elongated heating surface 1. And the sealed space 2, the heat medium liquid 3 contained in the liquid reservoir 2a located at the lower end of the space 2, and the outside of the liquid reservoir 2a so as to come into contact therewith. It is provided with an electric heater 4 provided as a heating means for heating the heat transfer liquid 3.

The space portion 2 is formed by piercing the inside of the main body portion 11 or inserting the tube 12 therein. The liquid reservoir portion 2a is provided inside the pipe below the main body 11 by bending the pipe 12. As the heat transfer liquid 3, the same one as in the case of a hot plate can be used. Although not shown, the electric heater 4 is provided with an electric power source, an operating end, a temperature sensor, and a temperature controller, as in the case of FIG. 1, so that the heating medium 1 is heated to a desired temperature. The amount of evaporation is controlled. In this case, the temperature sensor is attached at a position where it does not hinder the transportation of the semiconductor element 101. Reference numeral 102 is a conveyance guide for the semiconductor element 101. Although the heating surface 1 has a groove shape in FIG. 2B, it may have a mountain shape as shown in FIG.

This heat block is operated as follows. When the heating medium 3 stored in the liquid reservoir 2a is heated by the electric heater 4 while being controlled by a control system (not shown) so that the temperature of the heating surface 1 becomes a desired temperature, saturated gas is generated and the pipe 12 The space 2 formed by the above is filled, and the inner wall of the tube 12 is touched to be liquefied. At this time, latent heat of condensation is given to the tube 12 to heat the heating surface 1. The liquefied heat transfer medium flows down from the tube wall, and when it is accumulated in the tube to some extent, it is collected in the liquid reservoir 2a and heated and evaporated again. Since a saturated gas having the same latent heat at the same temperature anywhere in the tube has such an effect, the heating surface 1 is uniformly heated over the entire area and has a uniform temperature, as in the case of the hot plate. Also, although the amount of heat released increases at both ends of the heating surface 1 and the portion where the semiconductor element 101 is placed, the temperature drop is prevented by the increase in the amount of gas condensed, and a generally uniform temperature is maintained. To be done. As a result, temperature variations are significantly reduced compared to conventional heat blocks. For example, in the case of the present embodiment, the variation in temperature could be easily set to about ± 2 ° C regardless of the size and the temperature.

FIG. 4 shows an example in which the heating surface 1 is inclined. By doing so, the returning of the liquefied heat medium liquid is improved, and the temperature of the heating surface 1 is made more uniform. Also, the semiconductor element 101 can be slid and conveyed.

FIG. 5 shows the structure of the tube 12 in the case where the heat block is a multi-row type. In this case, the respective pipes 12 are connected by a header pipe 13, and the electric heater 4 is provided so as to surround the header pipe 13. However, the electric heater 4 may be arranged below the header tube 13 so as to be in contact therewith. With such a structure, the structure is simplified and the saturated gas of the same pressure and temperature is supplied to all the pipes 12, so that all the multi-row heat blocks can be made to have a uniform temperature. .

[0023]

[Effect of device]

 As described above, according to the present invention, there are various changes in the amount of heat radiated from the heating surface of the contact heating device due to the contact of the object to be heated, the difference between the central part and the peripheral part, the flow of air, the change in the air temperature, etc. Even if it occurs or its change is rapid, the required amount of heat in the form of latent heat of saturated gas is immediately supplied as a natural phenomenon to maximize the temperature of the heated surface with high accuracy. It can be held uniformly. Further, since the contact heating device is formed only by providing the space corresponding to the heating surface and providing the heating means for heating the heat transfer liquid, the structure is simple and the manufacturing is easy. Therefore, the cost can be reduced. In addition, the initial temperature adjustment and adjustment after failure replacement, which were required in conventional equipment, are not necessary at all, and handling is extremely improved.

[Brief description of drawings]

FIG. 1 shows a structure of a hot plate of an embodiment, (a)
Is a cross-sectional view, and (b) is a view in which a description of the control system is added to the cross-section taken along line bb of (a).

FIG. 2 shows the structure of the heat block of the embodiment, (a)
Is a sectional view and (b) is a sectional view taken along line bb of (a).

FIG. 3 is a cross-sectional view showing another structure of the heating surface portion of the heat block of the embodiment.

FIG. 4 is a sectional view showing the structure of a heat block of another embodiment.

FIG. 5 is a perspective view showing a tube arrangement of a heat block of still another embodiment.

[Explanation of symbols]

 1 Heating Surface 2 Space 3 Heat Transfer Liquid 4 Electric Heater (Heating Means)

Claims (3)

[Scope of utility model registration request] 1. A contact heating device for heating an object to be heated by placing it on a heating surface and bringing it into contact with the heating surface, the heating medium liquid and its saturated gas being provided corresponding to substantially the entire area of the heating surface. A contact heating device, comprising: a space portion in which is placed and sealed; and a heating unit that heats the heat medium liquid. 2. The contact heating device according to claim 1, wherein the heating surface is a flat surface having a considerable spread. 3. The contact heating device according to claim 1, wherein the heating surface is an elongated surface.