JP2009231015A - Uniform heating control device of tabular member, and control method of the device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device capable of optimizing an individual electric power supply amount to a plurality of electric heaters used in a heat treatment process against a tabular member, and of controlling to achieve a state that the whole face has a uniform temperature matching the target temperature, that is, that there is no unevenness in temperature distribution. <P>SOLUTION: A uniform heating control device of the tabular member is equipped with a distribution thermometer 13 to measure the distribution temperature by arranging respective distribution temperature sensors in the vicinity of a plurality pieces of heaters H1 to H8 to constitute a hot plate 11 in order to heat the tabular member, the main temperature adjuster 14 in which by arranging the main temperature sensor in order to carry out automatic control at a position to best reflect the present temperature of the hot plate, an output command value (%) of all the heaters is obtained by that information, a uniform heating controller 16 in which by comparing individual temperatures obtained from the distribution thermometer and the current temperature obtained from the main temperature adjuster, a suitable output value (%) is sent to the individual heaters via an electric power adjuster, and the electric power adjuster 19 to carry out electric power control of the individual heaters. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a control device for uniformly heating the entire surface of a flat plate member and a control method for the device.

  For example, in order to uniformly heat a deposition target substrate called a substrate (SUBSTRATE) or the like to a constant target temperature, a hot plate (heater panel) installed at a constant distance is set to a uniform temperature. Must be controlled. In order to cope with an increasing substrate, it is required to maintain a large area hot plate surface at a uniform target temperature. Heating heaters are divided and arranged in advance in order to heat the hot plate evenly, but temperature differences occur partially due to the heating capacity difference of the heater and the heat conduction of the hot plate (metal) that mediates. To do. In order to eliminate this temperature difference, temperature control is required to maintain the same temperature for each heater.

  When each heater is controlled independently using a separate temperature controller: In order to suppress the expansion of the temperature difference between the heaters during the temperature rise, control for suppressing the temperature difference is required while exchanging information on the current temperature with each temperature controller. Each temperature controller is affected by the heat generated by the adjacent heater and the heat conduction of the plate, so the required temperature characteristics cannot be obtained only by the amount of heat generated by the corresponding heater, and each temperature controller has an appropriate temperature. It is difficult to obtain the heating conditions necessary for adjustment. 3. In addition, an automatic temperature controller for the number of heater control points is required, and control for “same temperature adjustment” is required for soaking in the temperature rising process. And the resulting costs increase proportionally.

  In order to deal with such a problem, for example, there is an invention disclosed in Japanese Patent Application Laid-Open No. 2005-174943, which is a low-cost and simple configuration for temperature distribution in a heating region between a plurality of panel heaters. The object is to provide a method and apparatus that can be uniformized in a short time. The invention of the same number has a heater facing the partitioned heating surface to be heated, and is provided with a gas flow hole to flow a gas having a temperature lower than the heater set temperature, so that the gas has an effect on the heating target. The effect cannot be avoided. Further, it takes time to guide the gas to the target position and flow time, and it is not suitable for the substrate such as the substrate described above. Japanese Patent Laid-Open No. 2001-336880 discloses an invention related to soaking control of a plasma display panel baking furnace, and the temperature of a specific heater block deviates from the set temperature due to a set temperature difference between the heater blocks. The glass substrate can be heated uniformly. However, it is considered to be the same as in the past in that “individual temperature control” by a plurality of heaters is required.

JP-A-2005-174943 JP 2001-336880 A

  The present invention has been made paying attention to the above points, and the problem is that it is used in a heat treatment process for a flat member such as a substrate in a vacuum film forming process of a semiconductor, a flat panel display (FPD), a thin film solar cell panel or the like. Optimize the individual power supply amount to multiple electric heaters (electric heating means) to be controlled so that the temperature is consistent with the target temperature and the entire surface is uniform (there is no uneven temperature distribution) It is to provide a control device capable of performing the above. Another object of the present invention is to provide a control method having an extremely simple configuration and capable of automatically optimizing the output to each heater that is automatically and uniformly controlled under main temperature control. That is.

  In order to solve the above-described problems, the present invention relates to a soaking control device having a hot plate for uniformly heating the entire surface of a flat plate-like member, each having a distributed temperature in the vicinity of a plurality of heaters constituting the hot plate. A distribution thermometer that measures the distribution temperature by arranging the sensor and a main temperature sensor for automatic control to the position that best reflects the current temperature of the hot plate are arranged, and the output command value (%) of all heaters with that information Compare the individual temperature obtained from the distribution thermometer with the current temperature obtained from the main temperature controller, and supply the appropriate output value (%) to the individual heater via the power regulator. Means for providing a soaking controller and a power regulator for controlling the power of individual heaters are provided (claim 1).

  The distributed thermometer in the above configuration processes temperature signals from the same number of distributed temperature detection sensors as the number of heaters and converts them into individual temperatures. The soaking controller is an individual temperature obtained from the distributed thermometer. The temperature difference between the relevant position is calculated from the current temperature information and the main current temperature information obtained from the main temperature controller, and the heating amount commanded by the main temperature controller is optimized. The apparatus of the present invention makes it possible to control a flat member to be heated so that there is no uniform temperature, that is, a temperature difference or uneven temperature distribution, using a heater, that is, an electric heating means.

  Further, in the present invention, a temperature difference is obtained based on the temperature measured by the main thermometer and the distribution temperature measured by the distribution thermometer, and the soaking controller for adjusting the obtained temperature difference, and the target temperature As a control method for an apparatus comprising a main temperature controller that collectively manages power and individual power regulators, the main temperature control is performed so that a hot plate having a plurality of heaters matches a target temperature. When supplying appropriate power to all heaters with the output determined by the meter, the current temperature in the vicinity of each heater is measured by the distributed temperature sensor located in each heater, and Using the lowest temperature as a reference, calculate the temperature difference from each distribution temperature, calculate the suppression amount using the calculated temperature difference as an overpower, and use the suppression controller to send the command signal to the main temperature controller To the power regulator To optimize the output, optimizing so that uniform heating balance of the parts of the hot plate, and take measures that go through the process for equalizing the surface temperature (claim 2).

  By the above method, the soaking control device according to claim 1 is most appropriately controlled, and the flat plate member to be heated can be heated to a uniform temperature, that is, a temperature difference and a temperature distribution non-uniformity.

  Since the present invention is configured and operates as described above, it is possible to provide a flat member uniform heating apparatus capable of automatically adjusting the balance of individual heater outputs with the above simple configuration. There is an effect. Further, according to the present invention, it is applied to a heat treatment process of a flat member such as a substrate to be heated, and an electric heating means such as a heater is brought into a uniform heating state without temperature difference and temperature distribution unevenness. It is possible to reduce the occurrence of product defects due to the temperature difference of substrate heating in the vacuum film formation process, and to contribute to the reduction of power in order to limit the excess power, and the equipment There is an effect that it is possible to reduce the burden for designing and adjusting the heat quantity design of the heater in the design process.

Hereinafter, the present invention will be described in more detail with reference to the illustrated embodiments.
<Configuration of uniform heating device for flat plate member>
FIG. 1 is an explanatory view of a flat plate member soaking control apparatus 10 showing an example of the present invention, and 11 shows a hot plate (heater panel) for uniformly heating the entire surface of the flat plate member. A uniform heating mechanism for heating the substrate is configured. In the case of the hot plate 11 shown in the figure, eight heaters 12 having the symbols H1 to H8 having a capacity capable of heating the entire surface to a target temperature are arranged on the surface of the hot plate 11 in advance.

  The substrate heating mechanism in the actual machine varies depending on the processing method, and the heater heat capacity design and arrangement for keeping the entire surface of the hot plate at a uniform temperature under a plurality of conditions such as heating characteristics, thermal conductivity, and disturbance. Is not easy. For this reason, in the apparatus of the present invention, each of the eight heaters H1 to H8 in FIG. 1 has an appropriate heating capacity necessary for heating each of the eight divided regions on the surface of the hot plate, and In addition, the empirical value and the actual measurement value obtained in advance are taken into consideration, and it is assumed that the heating position is suitable for the heat treatment. The area of the hot plate 11 is such that the entire surface of the flat plate member can be heated uniformly. As the heaters H1 to H8, a sheath heater was used, and suitable results could be obtained.

  In addition, at the positions of the heaters H1 to H8, a number of distributed temperature detection sensors TC1 to TC8 equal to the number of heaters are arranged one by one. The distributed temperature detection sensors TC1 to TC8 are arranged at positions near the heaters that are affected by the heat of the individual heaters H1 to H8, and the surface of the hot plate heated by these heaters is an object to be heated. The main target temperature detection sensor TC-M is disposed at a position that most reflects the temperature of the flat plate member such as a substrate. Thermocouples are suitable as temperature sensors used for these temperature detection sensors TC1 to TC8 and TC-M.

  In the temperature detection sensors TC1 to TC8, temperature data is sequentially taken in at a high speed by the device distribution thermometer 13 controlled by the soaking controller 16 of the soaking controller 15, and the obtained current temperature information is soaking. It is sent to the controller 16 and stored as current temperature information of the position.

  The apparatus of the present invention includes a main temperature controller 14 for calculating an output signal necessary for automatically controlling the temperature of the hot plate 11 and the individual heaters H1 to H8 for the purpose of adapting the main current temperature to the main target temperature. A soaking controller 16 for optimizing the output is provided. The main temperature controller 14 recognizes the hot plates 11 used for substrate heating as a group, and issues a command signal to the soaking control unit 15 described below for the purpose of automatically controlling the target temperature of the panel 11. is there.

  The soaking control unit 15 corresponds to a sub-temperature controller because it calculates and controls the temperature control command signal from the main temperature controller 14 and the temperature difference between the individual heaters. That is, the soaking controller 16 uses the temperature information obtained from the distribution thermometer 13 at the individual heater position and the main current temperature information of the hot plate 11 obtained from the main temperature controller 14 as the corresponding temperature and reference. Measures the temperature difference between the temperatures, performs output suppression control to match it with the reference temperature, matches the command value (%) issued by the main temperature controller 14 and the adjustment value (%), It is an automatic gain (gradient) adjuster for supplying an output value (%) proportional to the heating amount to the power adjuster 19. In the figure, reference numeral 17 denotes a temperature difference detection unit, and 18 denotes an output control unit, which constitutes the suppression control unit 12.

  The power regulator 19 described above is composed of the same number of the heaters H1 to H8 that are divided and arranged on the surface of the panel body in order to uniformly heat the entire surface of the flat plate member. It is a device that can control the amount of heat by adjusting the. In the illustrated example, a thyristor is used as the power regulator 19.

<Control method of uniform heating device for flat plate member>
The flat member uniform heating apparatus according to the present invention having the above-described configuration operates and controls as described below.

<Main temperature control method>
The main temperature controller 14 obtains an output signal for matching the current temperature measured by the main temperature detection sensor 20 with the target temperature. The power regulator 19 uses a thyristor (SCR 1-8) as a temperature controller with a general-purpose temperature controller, adjusts the output signal to a power proportional to this as a command, and outputs it to the heaters H1-8. Heat.

<Regulation of treatment state by temperature during heating process>
At this time, the case where the current temperature (PV) is not achieved at the temperature reaching position obtained by subtracting the temperature difference (X) separately defined in advance from the target temperature (SV) is defined as “heating”, and When the temperature reaches that temperature, the temperature is defined as “soaking”, and the current temperature above the main target temperature is defined as “overheating”.

<Individual temperature measurement>
The current temperature in the vicinity of the heaters H1 to H8 is read by the distribution thermometer 13, and each temperature on the panel is grasped.

<Method of suppressing output of each heater due to temperature difference>
As shown in FIG. 2, the thyristors (SCR 1 to 8) that control the electric power according to the output command from the main temperature controller 14 in the “rising” process, as shown in FIG. A difference in the temperature of the panel surface will occur. Therefore, in the present invention, among the temperature information of the current temperature measured by the distribution thermometer 13, the lowest temperature (TC2, TC7, only during temperature increase in the example of FIG. 2) is set as the reference temperature, and the current values at other locations. The temperature difference from the temperature is calculated. The calculated temperature difference is calculated and processed as “transient output (%)” of each of the heaters H1 to H8, and is adjusted to an adjustment signal “command (power%)” uniformly commanded from the main temperature controller 14. (Suppression value = gain adjustment (%)) is synthesized to obtain (command value (%) * adjustment value (%) = output value (%)), and a command to the corresponding power regulator 19 (SCR 1 to 8) is issued. (Repeat thereafter)

  In the example of FIG. 2, the output to the heater of the hottest TC7 is most suppressed, and then the output to the hotter TC4, TC3 and TC6 is suppressed. As a result, during temperature rising, the main temperature controller is collectively adjusted for all the panels while individually adjusting the outputs of the heaters H1 to H8 so that the temperature distribution at each point becomes uniform with reference to the position where the temperature raising efficiency is low. Heat treatment can be performed under the control of 14. Further, the effect of the present invention will be described with reference to FIG. FIG. 3 shows the change in temperature distribution before and after the application of the present invention. In FIG. 3A, in the heating process targeting 200 ° C., the temperature difference of the eight heaters ranges from about 188 to 205 ° C. and exceeds 20 ° C. The temperature difference after application of the present invention is in the range of about 200 to 204 ° C. FIG. 3B shows the case where the present invention is applied during the temperature rise of 70 ° C., and the eight heater temperatures reach about 60 to 72 ° C. at the start of the control as described above, and the temperature difference of about 12 ° C. In contrast, after application of the present invention, the temperature difference is in the range of about 69-72 ° C. and about 3 ° C. Thus, the remarkable effect of the present invention could be confirmed by showing a tendency that a large temperature difference before application of the invention is remarkably reduced after application and converges.

According to the present invention showing such a configuration and effect, the following matters are possible.
・ Hot plate (heater panel), which is an assembly of individual heaters, is defined as a group and the temperature is controlled under the control of one temperature controller, and the entire heater is heated by fine adjustment of the output of each individual heater. Therefore, it is possible to perform soaking without greatly affecting the temperature control conditions necessary for the control, and as a result, management to the main target temperature can be simplified to a minimum.
・ Temperature unevenness generated on the heater panel is repeatedly fine-adjusted (gain adjustment) at any time, making it possible to control soaking without changing the temperature control conditions of the main temperature controller (PID parameters, etc.) It is possible to cope with changes in various heating conditions during the heating process without using complicated definitions.
A large number of temperature measuring distribution thermometers 13 required for individual adjustment do not require high-speed response enough to continuously monitor changes in temperature, and therefore use a scanner method (temperature switching) method. It is possible to measure with a thermometer on the table.

It is explanatory drawing which shows an example of the soaking | uniform-heating control apparatus of the flat member which concerns on this invention. It is a graph which shows the specific example of the soaking | uniform-heating control in the heating control method of the soaking | uniform-heating control apparatus of a flat member similarly. The effect of the present invention is shown. A is a graph showing a change in temperature difference before and after application of the present invention at 200 ° C., and B is a graph showing a change in temperature difference before and after application of the present invention during 70 ° C. is there.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Soaking control apparatus of flat plate member 11 Hot plate 12 Inhibition control part 13 Distribution thermometer 14 Main temperature controller 15 Soaking control apparatus
16 Heat equalization controller 17 Temperature difference detection unit 18 Output control unit 19 Power regulator 20 Main temperature detection sensor H1 to H8 Heater SCR1-8 Thyristor as temperature controller TC1 to TC8 Temperature detection sensor

Claims (2)

A soaking control device having a hot plate for uniformly heating the entire surface of a flat plate member,
A distribution thermometer that measures the distribution temperature by arranging a distribution temperature sensor near each of the plurality of heaters constituting the hot plate;
A main temperature controller that automatically controls the main temperature sensor to the position that most reflects the current temperature of the hot plate, and obtains the output command value (%) of all heaters with that information, and
A soaking controller that compares the individual temperature obtained from the distributed thermometer with the current temperature obtained from the main temperature controller and sends an appropriate output value (%) to the individual heater via the power regulator,
A soaking control device for a flat plate member comprising the above power regulator for controlling the power of each heater. A temperature difference is obtained based on the temperature measured by the main thermometer and the distribution temperature measured by the distribution thermometer, and a temperature equalization controller for adjusting the obtained temperature difference and a target temperature are collectively managed. A method for controlling an apparatus comprising a temperature controller and individual power regulators,
When supplying appropriate power to all heaters with the output determined by the main temperature controller in order to match the hot plate with multiple heaters with the target temperature,
Measure the current temperature in the vicinity of each heater with the distribution temperature sensor arranged in each heater, calculate the temperature difference with each distribution temperature based on the lowest temperature in the distribution temperature group,
Calculate the amount of suppression using the calculated temperature difference as the excess output, synthesize the result with the command signal of the main temperature controller in the suppression control unit, optimize the output to the power regulator,
A heating control method for a flat plate member soaking control device, wherein the heating balance of each part of the hot plate is optimized so as to be uniform, and the surface temperature is made uniform.

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