JP2010170815A - Heating and cooling unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heating and cooling unit in which the temperature changing speed is increased while maintaining soaking performance in cooling and the time required for stabilizing the temperature of a heater after cooling finish is shortened, thereby, a treating object is mounted promptly to attain an improvement in throughput. <P>SOLUTION: The heater unit 10 includes a heater substrate 1 made of, preferably, ceramics having a mounting face for mounting and treating a treating object and a cooling block 2 for cooling the heater substrate 1, and an inclusion layer 6 of a certain height exists between the heater substrate 1 and the cooling block 2. The inclusion layer 6 is arranged with a density distribution in which a region which becomes relatively a high temperature part in heating of the heater substrate 1 becomes high density than the region which becomes relatively a low temperature part. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a heater unit mainly used when heating a semiconductor substrate or a flat display panel substrate and a manufacturing / inspection apparatus equipped with the heater unit, and in particular, a heat treatment apparatus used in a photolithography process or a prober inspection process, or The present invention relates to a heat treatment apparatus used in a final inspection process of a semiconductor substrate.

  Many devices have been developed that can place an object to be heated and heat-treat it. Of these, a semiconductor device is particularly required to have a uniform temperature distribution of the object to be heated (hereinafter also referred to as "uniform temperature"). And heater units used for heating semiconductor substrates and glass substrates in the production of flat display panels. This heater unit is used, for example, for heating and drying a resist solution applied on a substrate in a lithography process, or used for raising a temperature for performing a substrate inspection process at a desired temperature.

  Thus, when processing a several process process using one heater unit, it is normally performed in the following procedures. First, the heating element circuit of the heater unit in a low temperature state is energized to raise the temperature, and then the object to be heated is placed on the placement surface of the heater unit to raise the temperature of the object to be heated. When the predetermined temperature is reached, the object to be heated is processed while maintaining this temperature. When this process ends, the object to be heated is taken out from the placement surface, and the next object to be heated is placed on the placement surface. When the predetermined number of processes are completed, the temperature condition of the heater unit is changed to perform another process. When the temperature condition after the change is stabilized, an object to be heated in another process is mounted on the heater substrate, and thereafter the same processing is performed.

  By the way, in the production of semiconductor devices and flat display panels, it is competing to reduce the price of products by mass production through continuous operation, and shortening of the tact time is demanded in manufacturing and inspection devices. Therefore, in order to obtain a high throughput while processing a plurality of processes using one heater unit, not only the processing time of the object to be processed during the temperature maintenance time but also the change of the heater temperature accompanying the change of the processing conditions It is necessary to shorten the time required for heating (heating time, cooling time).

  For this reason, the present inventors have already made it possible to move a cooling block having a predetermined heat capacity relative to the heater substrate in a heater unit composed of a heater substrate and a cooling block, so that the cooling block is heated during heating. Invented to quickly cool the heater substrate and the heated object placed on the heater substrate by bringing the cooling block into contact with the heated heater substrate at the time of cooling. Patent Document 1). As a result, the time required for the heat treatment could be reduced.

  Although the temperature of the object to be heated can be cooled in a short time by the above invention, in order to place the next object to be heated on the heater substrate after cooling, temperature variation in the placement surface that occurs during cooling It has been necessary to wait until the temperature converges and the temperature of the heater substrate becomes substantially uniform over the entire surface of the mounting surface.

  Therefore, the present inventors have arranged an intervening layer between the cooling block and the heater substrate to reduce the temperature variation in the mounting surface of the heater substrate at the time of the temperature change described above, and after reaching a predetermined temperature The invention which can heat-process a to-be-processed object on the following process conditions rapidly was performed (patent document 2).

JP 2004-014655 A JP 2007-059178 A

  However, when the intervening layer is disposed between the cooling block and the heater substrate, the intervening layer becomes a thermal resistance during cooling, and it may take a long time to cool. Further, holes or the like are provided in the cooling block and the heater board in order to mount or insert a power supply terminal for supplying power or a support pin for supporting the object to be processed, and these parts are physically provided in the heater board. Since it does not abut, it cannot be cooled effectively, and there is a limit to the reduction in temperature variation within the mounting surface that occurs during cooling.

  The present invention has been made in view of the above-described problems. The temperature change rate is increased while maintaining the thermal uniformity during cooling in the same manner as in the prior art or better than in the prior art. The purpose is to improve the throughput by reducing the time required to stabilize the temperature so that the next workpiece can be quickly placed.

  With the improvement, especially in the manufacturing process of semiconductor devices and flat display panels, by performing heat treatment under the following conditions immediately after changing the temperature conditions, and by achieving high in-plane thermal uniformity, in the semiconductor process, For example, an object is to reduce variations in film thickness and line width in the photoresist process. Furthermore, it aims at improving the productivity, performance, yield, and reliability of semiconductor devices and flat display panels manufactured through this heat treatment step.

  As a result of intensive research in order to solve the above problems, the present inventors have arranged an intervening layer having a certain height between the cooling block and the heater substrate in the heater unit including the heater substrate and the cooling block. In this case, by disposing the intervening layer with a density distribution in the plane, the temperature can be changed quickly without impairing the thermal uniformity in the plane and without sacrificing the cooling time. It has been found that the time required for mounting can be shortened, and the present invention has been completed.

  That is, the heater unit provided by the present invention includes a heater substrate having a placement surface for placing and processing an object to be processed, and a cooling block for cooling the heater substrate. And an intervening layer between the cooling block and the intervening layer has a higher density in a region that becomes a relatively high temperature portion when the heater substrate is heated than a region that becomes a relatively low temperature portion. It is characterized by being arranged with a density distribution such that

  In the heater unit of the present invention, it is preferable that the intervening layer is present at a relatively high density in the vicinity of the counterbore or the through hole formed on the surface facing the heater substrate in the cooling block. .

  In the heater unit of the present invention, it is preferable that the cooling block is in contact with the heater substrate when the heater substrate is cooled and is separated from the heater substrate when the heater substrate is heated.

  According to the present invention, it is possible to reduce the temperature variation in the mounting surface that occurs during cooling without sacrificing the required cooling time, and to shorten the time until the workpiece is placed after the temperature change. Thus, throughput can be improved.

  As a result, particularly in the manufacturing process of a semiconductor device or a flat display panel, the heat treatment can be performed immediately under the next processing condition after the temperature condition is changed. In addition, by achieving high in-plane thermal uniformity, it is possible to reduce variations in film thickness and line width in, for example, a photoresist process in a semiconductor process. As described above, when a workpiece such as a semiconductor device or a flat display panel is manufactured using the heater unit of the present invention, productivity, performance, yield, and reliability can be improved.

It is a schematic sectional drawing which shows one specific example of the heater unit of this invention. FIG. 2 is a schematic cross-sectional view schematically showing a separated state and a contact state of the heater unit of FIG. 1. It is a top view which shows one example of arrangement | positioning of the intervening layer which the heater unit of this invention has. It is a fragmentary sectional view showing the example which arranged the intervening layer densely around the penetration hole of a cooling block. It is a top view which shows the other example of arrangement | positioning of the intervening layer which the heater unit of this invention has. It is a graph which shows the heat_generation | fever density of a heat generating body circuit.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing a specific example of the heater unit 10 of the present invention, a heater substrate 1 having a mounting surface 1a for mounting and processing an object to be processed such as a semiconductor wafer, A cooling block 2 for cooling the heater substrate 1 is provided.

  The heater substrate 1 is provided with a heating element circuit 3 on a surface opposite to the mounting surface 1a on which the object to be processed is mounted (hereinafter referred to as the back surface of the heater substrate 1). A power supply wiring (not shown) for supplying power to the circuit 3 and a temperature sensor (not shown) for monitoring the temperature of the heater substrate 1 are connected. The heating element circuit 3 is disposed in a spiral heater pattern by etching stainless steel or nickel-chrome foil, for example.

  The heating element circuit 3 can be arranged with a density distribution in the plane of the heater substrate 1. For example, when a gap is expected to be generated between the placement surface 1a of the heater substrate 1 and the object to be processed due to warpage of the object to be processed, the amount of heat generated per unit area of the region where the gap is generated ( The temperature distribution in the surface can be made uniform by arranging the heating element circuit 3 so that the heat generation density is higher than that in other regions.

  Further, since the heater substrate 1 has a relatively large amount of heat radiated from a region or side surface on which the object to be processed on the placement surface 1a is not placed, the heater substrate 1 is arranged so that the heat generation density of the outer peripheral portion becomes high in order to compensate for the heat radiation. By doing so, the in-plane temperature distribution can be made uniform. The arrangement of the heating element circuit 3 so as to locally vary the heat generation density in this way can be realized with only a single heating element circuit 3, but a plurality of heating element circuits 3 are arranged on the back surface, for example, It can also be realized by separately providing the peripheral portion and the outer peripheral portion, or by further dividing the inner peripheral portion and the outer peripheral portion in the circumferential direction.

  An electric insulating sheet 4 and a back plate 5 as a pressing plate are further disposed on the back side of the heater substrate 1 (hereinafter, the heater substrate 1, the heating element circuit 3, the electric insulating sheet 4 and the back plate 5 are connected). Collectively referred to as heater module). The relatively strong back plate 5 and the heater substrate 1 are mechanically connected by using, for example, screws or the like with an electrical insulating sheet 4 interposed therebetween. It is desirable to use the electrical insulating sheet 4 having a high thermal conductivity as much as possible. If the electrical conductivity of the electrical insulating sheet 4 is high, the in-plane temperature distribution caused by factors such as the structure of the heating element circuit 3 and the environment can be reduced, and the heater unit 10 with high heat uniformity can be provided. Because.

  In addition, it is preferable to use a flexible material for the electrical insulating sheet 4 in order to favorably diffuse the heat of the heating element circuit 3 on the back surface side of the heater substrate 1. If the electrical insulating sheet 4 is more flexible than the heater substrate 1 and the back plate 5, it is possible to fill a small gap caused by the flatness of each and the back plate 5 by eliminating local heat resistance. This is because it is possible to provide a heater unit 10 that maximizes the effects of heat conduction and heat capacity, has high heat uniformity, and is stable against disturbances such as the environment. In addition, the flatness of a surface means the distance between the two planes when assuming two planes with the shortest distance between two planes parallel to each other with the plane interposed therebetween. .

  The electrical insulating sheet 4 can be selected from, for example, silicone resin, fluororesin, polyimide resin, ceramic fiber sheet, mica, and the like. As described above, the silicone resin can contribute to the improvement of the heater characteristics utilizing the flexibility, and the fluororesin, polyimide resin, ceramic fiber sheet, mica and the like can be used even in a temperature range exceeding 200 ° C. In particular, mica can be used even in a temperature range exceeding 500 ° C. and is excellent in electrical insulation, so that it is suitable for use in a high temperature range.

  In this case, the mica and the heating element circuit 3 can be integrated by thermocompression bonding. By integrating, the mutual adhesion increases, and the thermal resistance at these interfaces can be lowered. That is, it is possible to maximize the effects of heat conduction and heat capacity of the back plate 5 by eliminating local heat resistance. Further, by integrating, even when the heating element circuit 3 is repeatedly expanded and contracted under the influence of a thermal environmental load, a positional deviation in the plane direction is less likely to occur, and a highly reliable heater unit. 10 can be provided. The electrical insulating sheet 4 may be formed by coating on, for example, a spiral heating element circuit 3 disposed on the back surface of the heater substrate 1.

  A highly heat conductive sheet (flexible and high in thermal conductivity in the plane direction) between the electrical insulating sheet 4 and the back plate 5 or between the heating element circuit 3 and the heater substrate 1 compared to the heater substrate 1 and the back plate 5 ( (Not shown) may be arranged. For example, an aluminum sheet having a thermal conductivity of 100 to 250 W / m · K, a copper sheet having a thermal conductivity of 400 W / m · K, and a graphite sheet having a thermal conductivity of 200 to 1700 W / m · K are used as the high thermal conductivity sheet. be able to.

  When the heater substrate 1 is conductive, or when the above-described high thermal conductive sheet is formed of a conductive material and is disposed between the heating element circuit 3 and the heater substrate 1, the heating element circuit 3 Insulating sheets for ensuring insulation are loaded between the heating element circuit 3 and the heater substrate 1 in the former case, and between the heating element circuit 3 and the high thermal conductive sheet in the latter case.

  The thickness of the heater substrate 1 is formed thin in order to reduce the heat capacity and shorten the time required for temperature change. As described above, although the temperature change can be speeded up by forming the heater substrate 1 thin, the heat uniformity on the placement surface 1a may be impaired. Therefore, it is desirable that the back plate 5 provided just below the heater substrate 1 and the heating element circuit 3 has a particularly good thermal conductivity. Moreover, it is preferable that the screw for connecting the heater substrate 1 and the back plate 5 is provided with a bearing.

  Thereby, in the axial direction of the screw, the heater substrate 1 and the back plate 5 are fixed so as not to move relatively, and in the direction intersecting the axial direction, the heater substrate 1 and the back plate are supported by the bearings. 5 can absorb the difference in thermal expansion between the heater substrate 1 and the back plate 5, and the heater substrate 1 and the back plate 5 can change in flatness due to the mutual thermal expansion difference. It is not generated and good heat conduction is maintained.

  The material having good thermal conductivity used for the back plate 5 is, for example, an aluminum plate having a thermal conductivity of 100 to 240 W / m · K, a copper plate having a thermal conductivity of 400 W / m · K, or heat including any of them. Metals such as alloys having a conductivity of 200 to 700 W / m · K, aluminum nitride having a thermal conductivity of 100 to 200 W / m · K, ceramics such as silicon carbide having a thermal conductivity of 200 to 300 W / m · K, or these ceramics And ceramic metal composites made of metal.

  The main component of the heater substrate 1 is preferably selected from the group consisting of aluminum nitride, silicon carbide, aluminum oxide, silicon nitride, copper, aluminum, nickel, and silicon. Among these, ceramics are preferable if possible. This is because when metal is used, particles that are avoided in the microfabrication process of the device manufacturing process are generated and may adhere to the wafer. Furthermore, since ceramics have high processing accuracy, the flatness of the mounting surface 1a on which the workpiece is placed can be finished with high accuracy.

  Among ceramics, if importance is placed on soaking, aluminum nitride or silicon carbide having high thermal conductivity is preferable. On the other hand, if importance is placed on reliability, aluminum nitride and silicon nitride are preferable because they are high in strength and resistant to thermal shock. Moreover, if importance is attached to the cost, aluminum oxide is preferable. Furthermore, if the heater substrate 1 is insulative, it is not necessary to interpose the aforementioned insulating sheet between the heater circuit 3 and the aluminum nitride and aluminum oxide that are insulative from the viewpoint of cost and thermal resistance. Or silicon nitride.

  Since the present invention has a problem of soaking at the time of temperature change and shortening of the heating / cooling time, among the above materials, high thermal conductivity for soaking and thermal shock resistance to withstand temperature change, Furthermore, aluminum nitride which is an insulating material capable of reducing thermal resistance is preferable.

  If necessary, the heater unit 10 may incorporate a mechanism (not shown) for moving the cooling block 2 and the heater substrate 1 relatively to contact / separate each other. For example, an elevating mechanism (not shown) made of an air cylinder or the like may be provided on the opposite side of the surface of the cooling block 2 facing the heater substrate 1, and the cooling block 2 may be moved up and down using this mechanism. Thereby, the heater substrate 1 and the cooling block 2 can be separated from each other as shown in FIG. 2A, or can be brought into contact with each other as shown in FIG.

  It is preferable that the elevating mechanism such as the air cylinder has a large thrust acting in the direction of contacting the heater substrate 1 as much as possible under the constraints of the installation environment of the heater unit 10 and the allowable weight and dimensions. As a result, the thermal resistance generated on the abutting surface between the cooling block 2 and the back plate 5 can be reduced, and the time required for cooling is shortened as well as the local thermal resistance is eliminated. It is possible to achieve soaking on the surface 1a. Specifically, the thrust of the lifting mechanism such as the air cylinder is preferably equal to or greater than the weight of the cooling block 2.

  The main component of the cooling block 2 is preferably selected from the group consisting of copper, aluminum, nickel, magnesium, titanium having good thermal conductivity, or an alloy (or stainless steel) containing these as main components. In particular, since copper has a large heat capacity, the amount of heat taken away from the object to be cooled is large when adopting the above-described contact / separation structure, which is suitable for cooling at high speed. Moreover, you may surface-treat to the base | substrate which comprises the cooling block 2 as needed. As such surface treatment, nickel plating with high corrosion resistance and oxidation resistance is desirable.

  A coolant channel (not shown) is formed in the cooling block 2, and the coolant can be circulated therethrough. In this method of forming the refrigerant flow path, a metal pipe is used, and the pipe is mechanically connected to the cooling block 2 using a screw or the like that connects the base body and the mounting part constituting the cooling block 2. There is a method (hereinafter referred to as a pipe method).

  In addition, a groove serving as a flow path is formed by machining on one side of the base body constituting the cooling block 2, and another base body having the same component as the base body is stacked so as to cover the flow path. There is also a method of integrating by means such as attaching. In the latter method, the groove serving as the flow path may be processed only in one of the two substrates that are overlapped with each other, or may be processed in both of them facing each other. Compared to the pipe method, the method of processing the groove serving as the flow path is preferable because the refrigerant directly contacts the base body of the cooling block 2, so that the heat exchange efficiency is high and the cooling is performed at high speed.

  Between the back plate 5 and the cooling block 2, there is an intervening layer 6 having a certain height. The intervening layer 6 is arranged with a density distribution in a surface where the cooling block 2 and the heater substrate 1 are in contact with each other (hereinafter referred to as a contact surface). That is, the intervening layer 6 is not arranged uniformly in the surface direction of the contact surface, but is arranged or not arranged depending on the location (hereinafter, such in-plane arrangement). Is also referred to as arrangement density). For example, in the cooling of the heater substrate 1, the outer peripheral surface area is wider than the inner peripheral surface area of the heater substrate 1 and heat dissipation is easier, so the outer peripheral portion tends to cool faster than the inner peripheral portion. Therefore, it is preferable to arrange the intervening layer 6 so that the inner peripheral portion is denser than the outer peripheral portion.

  Further, since the cooling block 2 is provided with a support pin for supporting the object to be processed and a counterbore or a through hole (not shown) through which the above-described temperature sensor is mounted or inserted, the intervening layer 6 has It is preferable to arrange the counter holes and the through holes so as to be dense. This is because when these counterbores and through holes are opened in the cooling block 2, portions corresponding to the counterbores and through holes in the heater substrate 1 are portions that do not contact the cooling block 2 and do not cool locally. For this reason, it is preferable to arrange the intervening layer 6 so that the intervening layer 6 is denser than other regions in the peripheral region of the counterbore or the through hole in order to cancel it. As a result, a cooling rate equivalent to that in other regions is realized, and temperature variations in the wafer mounting surface 1a are suppressed.

  Furthermore, since the cooling block 2 is provided with through holes (not shown) through which the above-described power supply terminals are inserted, it is preferable that the intervening layer 6 is arranged so as to be dense around these through holes. This is because the heat generation density of the power supply part is designed to be high for the purpose of canceling out heat escape from the power supply terminal during heating of the heater, so that the temperature can be stabilized when the workpiece is placed or after cooling is completed. This is because the amount of heat generated is relatively increased in the power supply part compared to other parts during transient heat generation. That is, by arranging the intervening layer 6 densely around the through hole through which the power feeding terminal is inserted, the transient heat generation amount can be offset.

  The shape of the intervening layer 6 is not particularly limited as long as it can be arranged at a certain height with an appropriate density distribution, and may be circular or square, ring-shaped or other shapes. May be. The density distribution can be realized, for example, by dispersing a plurality of circular intervening layers 6 in the form of dots in the surface or by forming one or a plurality of holes in one sheet of intervening layer 6. Become. Alternatively, the dot-like intervening layer 6 and the sheet-like intervening layer 6 may be combined. The size of the dot or hole can be appropriately changed according to the installation location.

  For example, in FIG. 3, one circular sheet-shaped intervening layer 6 a is disposed on the inner peripheral portion excluding the periphery of the through-hole, and a plurality of fan-shaped or triangular sheet-shaped intervening layers 6 b are disposed on the outer peripheral portion excluding the periphery of the through-hole. An example in which the intervening layer 6c is arranged around the through-hole through which the temperature sensor is inserted, the intervening layer 6d is arranged around the through-hole through which the support pin is inserted, and the intervening layer 6e is arranged densely around the through-hole through which the power supply terminal is inserted. It is shown. FIG. 4 shows a schematic partial cross-sectional view showing the state in which the intervening layers are densely arranged around the through holes at a constant height, taking the intervening layer 6d as an example.

  In FIG. 5, one circular sheet-shaped intervening layer 6 a is disposed on the inner peripheral portion excluding the periphery of the through hole, and a plurality of dot-shaped intervening layers 6 f are disposed on the outer peripheral portion excluding the periphery of the through hole. An example is shown. 5, the intervening layer 6c and the intervening layer 6d are arranged as in FIG. 3, but a fan-shaped intervening layer 6g is arranged around the through hole through which the power supply terminal is inserted. The shape and density distribution of the intervening layer 6 are not limited to those shown in FIGS. 3 and 5 and can be appropriately changed depending on the heat generation density of the heating element circuit 3 and the external environment.

  The place where the intervening layer 6 is disposed may be a surface facing the back plate 5 on the cooling block 2 or a surface facing the cooling block 2 on the back plate 5. Or both sides may be sufficient. A preferable arrangement location is a surface facing the back plate 5 on the cooling block 2. This is because, on the surface facing the cooling block 2 on the back plate 5, a heat load is always applied to the intervening layer 6 from the heating element circuit 3, so that the intervening layer 6 is easily worn by the thermal history. Further, depending on the operating temperature of the heating element circuit 3, the specification of the intervening layer 6 and the method of attaching the intervening layer 6 are limited to specific ones from the viewpoint of the heat resistance of the intervening layer 6 used continuously.

  The material of the intervening layer 6 is preferably a heat-resistant material such as foam metal or metal mesh, graphite sheet, fluororesin, polyimide, silicone resin. The intervening layer 6 preferably has a high thermal conductivity. In particular, the thermal conductivity is preferably 1 W / m · K or more. If it is less than 1 W / m · K, the thermal resistance increases and the cooling rate becomes slow. In addition, it is preferable to use a resin containing a heat conductive filler such as carbon, for example, so that the thermal resistance is reduced and the resin can be cooled at high speed.

  Furthermore, the intervening layer 6 preferably has flexibility. If there is no flexibility, when the cooling block 2 is brought into contact with the back plate 5, it will not be able to adhere well due to the flatness of the two contact surfaces, and a gap will remain locally. It is because it becomes impossible to suppress the temperature variation at the time of cooling. On the other hand, if the intervening layer 6 has flexibility, the flatness of the abutting surfaces of the back plate 5 and the cooling block 2 and partial unevenness, protrusions, scratches, flashes generated by machining, It can absorb surface conditions such as burr and foreign matter. As such a material, a silicone resin is particularly preferable among the above-mentioned materials.

  The thickness of the intervening layer 6 is preferably thicker than the sum of the flatness of the surface facing the cooling block 2 on the heater module and the flatness of the surface facing the heater module on the cooling block 2. More preferably, it is within 3 mm. If less than 0.1 mm, a local gap is generated unless the sum of the flatness of the surface on the cooling block 2 on the heater module and the flatness of the surface facing the heater module on the cooling block 2 is less than 0.1 mm. In addition, it is not preferable that the flatness needs to be strictly controlled, because it is not suitable for mass production from the viewpoint of machining accuracy and cost. In addition, the thickness of the intervening layer 6 itself is too thin, which makes it difficult to handle and hinders stable production. On the other hand, if it exceeds 3 mm, the thermal resistance at the time of cooling increases excessively, the cooling rate becomes slow, and the heater unit 10 can be rate-limiting in making it compact.

  The flatness of the surface facing the cooling block 2 on the back plate 5 and the flatness of the surface facing the back plate 5 on the cooling block 2 are each preferably 0.5 mm or less. If the thickness exceeds 0.5 mm, it is difficult to maintain the contact property with the intervening layer 6, and the thickness of the intervening layer 6 may be increased to maintain the contact property. Because there is. It is preferable that the sum of the flatness of the surface facing the cooling block 2 on the back plate 5 and the flatness of the surface facing the back plate 5 on the cooling block 2 is 0.1 mm or less. By doing so, the thickness of the intervening layer 6 can theoretically be reduced to 0.1 mm, so that the thermal resistance is small and cooling can be performed at high speed.

  Furthermore, the area of the region where the intervening layer 6 is disposed is preferably 10% or more and 90% or less of the area of the surface of the cooling block 2 facing the heater substrate 1. This is because if the amount is less than 10%, the contact area becomes too small and the cooling rate becomes slow. In addition, when it exceeds 90%, it is difficult to realize a necessary arrangement distribution in the plane.

  The method for attaching the intervening layer 6 is not particularly limited as long as it can be fixed, but for example, it can be attached by using an adhesive means such as an adhesive, a double-sided tape, and an adhesive resin. Among these bonding means, those that are thin, have high thermal conductivity, and have low thermal resistance are desirable. In the case of a sheet having a certain size, it may be mechanically fixed by a coupling means such as screwing.

Next, the manufacturing method of the heater substrate 1 of the present invention will be described in detail by taking the case of aluminum nitride as an example. The AlN raw material powder preferably has a specific surface area of 2.0 to 5.0 m ² / g. When the specific surface area is less than 2.0 m ² / g, the sinterability of aluminum nitride is lowered. On the other hand, if it exceeds 5.0 m ² / g, the aggregation of the powder becomes very strong, making it difficult to handle. Furthermore, the amount of oxygen contained in the raw material powder is preferably 2 wt% or less. When the oxygen amount exceeds 2 wt%, the thermal conductivity of the sintered body decreases.

  The amount of metal impurities other than aluminum contained in the raw material powder is preferably 2000 ppm or less. When the amount of metal impurities exceeds this range, the thermal conductivity of the sintered body decreases. In particular, group IV elements such as Si and iron group elements such as Fe as metal impurities have a high effect of lowering the thermal conductivity of the sintered body, and therefore their contents may be 500 ppm or less, respectively. preferable.

  Since AlN is a hardly sinterable material, it is preferable to add a sintering aid to the AlN raw material powder. The sintering aid to be added is preferably a rare earth element compound. The rare earth element compound reacts with the aluminum oxide or aluminum oxynitride existing on the surface of the aluminum nitride powder particles during the sintering to promote the densification of the aluminum nitride and the thermal conductivity of the aluminum nitride sintered body. Therefore, the thermal conductivity of the aluminum nitride sintered body can be improved.

  The rare earth element compound is preferably an yttrium compound that is particularly effective in removing oxygen. The addition amount is preferably 0.01 to 5 wt%. If it is less than 0.01 wt%, it is difficult to obtain a dense sintered body, and the thermal conductivity of the sintered body decreases. If it exceeds 5 wt%, a sintering aid exists at the grain boundaries of the aluminum nitride sintered body. Therefore, when used in a corrosive atmosphere, the sintering aid present at the grain boundaries is etched. , Cause degranulation and particles. Furthermore, the preferable addition amount of the sintering aid is 1 wt% or less. If it is 1 wt% or less, the sintering aid is not present at the triple point of the grain boundary, so that the corrosion resistance is improved.

  In addition, oxides, nitrides, fluorides, stearic acid compounds, and the like can be used as the rare earth element compound. Of these, oxides are preferable because they are inexpensive and readily available. In addition, since the stearic acid compound has a high affinity with an organic solvent, when the aluminum nitride raw material powder and the sintering aid are mixed with the organic solvent, the mixing property is particularly preferable.

  Next, a predetermined amount of a solvent, a binder and, if necessary, a dispersant and a glaze are added to and mixed with the aluminum nitride raw material powder and the sintering aid powder. As the mixing method, ball mill mixing, ultrasonic mixing, or the like is possible. A raw material slurry can be obtained by such mixing. An aluminum nitride sintered body can be obtained by molding and sintering the obtained slurry. There are two types of methods, a cofire method and a post metallization method.

  First, the post metallization method will be described. The slurry is dried by a technique such as a spray dryer to produce granules. The granules are inserted into a predetermined mold and press-molded. At this time, the pressing pressure is desirably 9.8 MPa or more. When the pressure is less than 9.8 MPa, the strength of the molded body is often not sufficiently obtained, and is easily damaged by handling.

The density of the compact varies depending on the binder content and the amount of sintering aid added, but is preferably 1.5 g / cm ³ or more. If it is less than 1.5 g / cm ³ , the distance between the raw material powder particles becomes relatively large, so that sintering does not proceed easily. Moreover, it is preferable that the density of a molded object is 2.5 g / cm < ³ > or less. If it exceeds 2.5 g / cm ³ , it will be difficult to sufficiently remove the binder in the molded body by the degreasing treatment in the next step. For this reason, it becomes difficult to obtain a dense sintered body as described above.

  Next, the molded body is heated in a non-oxidizing atmosphere to perform a degreasing treatment. When the degreasing treatment is performed in an oxidizing atmosphere such as the air, the surface of the AlN powder is oxidized, so that the thermal conductivity of the sintered body is lowered. As the non-oxidizing atmosphere gas, nitrogen or argon is preferable. The heating temperature for the degreasing treatment is preferably 500 ° C. or higher and 1000 ° C. or lower. When the temperature is less than 500 ° C., the binder cannot be sufficiently removed, and therefore excessive carbon remains in the laminated body after the degreasing treatment, which inhibits sintering in the subsequent sintering step. Further, at a temperature exceeding 1000 ° C., the amount of remaining carbon becomes too small, so that the ability of the oxide film present on the surface of the AlN powder to remove oxygen is lowered, and the thermal conductivity of the sintered body is lowered.

  Moreover, it is preferable that the carbon amount which remains in the molded object after a degreasing process is 1.0 wt% or less. If carbon exceeding 1.0 wt% remains, sintering is inhibited, so that a dense sintered body cannot be obtained.

  Next, sintering is performed. Sintering is performed at a temperature of 1700 to 2000 ° C. in a non-oxidizing atmosphere such as nitrogen or argon. At this time, it is preferable that the moisture contained in the atmosphere gas such as nitrogen used is −30 ° C. or less in terms of dew point. In the case of containing more moisture than this, AlN reacts with moisture in the atmospheric gas during sintering to form oxynitrides, which may reduce the thermal conductivity. Moreover, it is preferable that the oxygen amount in atmospheric gas is 0.001 vol% or less. If the amount of oxygen is large, the surface of AlN may be oxidized and the thermal conductivity may be reduced.

  Furthermore, a boron nitride (BN) compact is suitable for the jig used during sintering. This BN compact has sufficient heat resistance to the sintering temperature and has a solid lubricating property on the surface thereof, so that there is a gap between the jig and the sintered compact when the sintered compact shrinks during sintering. Therefore, a sintered body with less strain can be obtained. The obtained sintered body is processed as necessary. Thereby, the ceramic sintered body used as the heater substrate 1 is obtained.

  The surface roughness of the mounting surface on which the object to be processed is mounted is preferably 5 μm or less in terms of Ra. When the Ra exceeds 5 μm, AlN may be shed more frequently due to friction between the heater substrate 1 and the workpiece. At this time, the shed particles become particles and have an adverse effect on processes such as film formation and etching on the object to be processed. The surface roughness is more preferably 1 μm or less in terms of Ra.

  When the heating element circuit 3 is formed, a conductive paste is applied to the ceramic sintered body by, for example, screen printing, degreased and fired. The conductor paste can be obtained by mixing metal powder, oxide powder as necessary, binder, and solvent. Further, when the electrical insulating sheet 4 is formed in order to ensure the insulation of the formed heating element circuit 3, a paste made of crystallized glass or the like is applied on the heating element circuit 3 by, for example, screen printing. If necessary, degreasing and baking.

  Next, the cofire method will be described. The raw material slurry described above is formed into a sheet by the doctor blade method. Although there is no restriction | limiting in particular regarding sheet formation, As for the thickness of a sheet | seat, 3 mm or less is preferable after drying. If the thickness of the sheet exceeds 3 mm, the amount of drying shrinkage of the slurry increases, so that the probability of cracking in the sheet increases.

  A metal layer to be an electric circuit having a predetermined shape is formed on the above-described sheet by applying a conductive paste by a technique such as screen printing. The same conductor paste as that used in the post metallization method can be used. However, in the cofire method, there is no problem even if the oxide powder is not added to the conductor paste.

  Next, the sheet on which the circuit is formed and the sheet on which the circuit is not formed are stacked. In the laminating method, each sheet is set at a predetermined position and overlapped. At this time, a solvent is applied between the sheets as necessary. In the state of being overlaid, heat as necessary. When heating, it is preferable that heating temperature is 150 degrees C or less. When heated to a temperature exceeding this, the laminated sheets change greatly. Then, pressure is applied to the stacked sheets to integrate them. The applied pressure is preferably in the range of 1 to 100 MPa. If the pressure is less than 1 MPa, the sheets may not be sufficiently integrated and may peel during the subsequent steps. Further, when a pressure exceeding 100 MPa is applied, the amount of change in the sheet becomes too large.

  This laminated body is degreased and sintered in the same manner as the above-described post metallization method. The degreasing treatment and sintering temperature, the amount of carbon, etc. are the same as in the post metallization method. When printing the above-mentioned conductor paste on a sheet, it is also possible to produce an energizing heat generating heater having a plurality of electric circuits. In this way, a ceramic laminated sintered body composed of the heater substrate 1 and the heating element circuit 3 can be obtained.

  When the electric circuit such as the heating element circuit 3 is formed in the outermost layer of the ceramic laminate, the same as the above-described post metallization method for the purpose of protecting and insulating the electric circuit and preventing oxidation. The electric insulating sheet 4 can be formed on the electric circuit.

  The heater unit according to the present invention described above is preferably mounted on a semiconductor manufacturing / inspection apparatus or a flat display panel manufacturing / inspection apparatus. As a result, the temperature can be raised and lowered faster than the conventional apparatus, the temperature distribution of the heater becomes more uniform, and the performance, yield, and reliability of the semiconductor and flat display panel can be improved. Further, the time required for the heat treatment process is shortened compared to the conventional apparatus, and the productivity of semiconductors and flat display panels can be improved.

  As mentioned above, although the heater unit of this invention was demonstrated based on embodiment, this invention is not limited to this embodiment, It can implement in the various aspect of the range which does not deviate from the main point of this invention. Should be understood. That is, the technical scope of the present invention extends to the claims and their equivalents.

[Example 1]
As an example according to the present invention, the heater unit 10 shown in FIG. 1 was manufactured by the following method. The heater substrate 1 made of ceramic, and aluminum nitride powder of 100 parts by weight, were mixed Y ₂ O ₃ powder of 0.5 parts by weight, a polyvinyl butyral binder, dibutyl phthalate as a solvent, respectively 10 parts by weight, 5 After mixing parts by weight and producing granules with a spray dryer, press molding, degreasing in a nitrogen atmosphere at 700 ° C., and sintering at 1850 ° C. in a nitrogen atmosphere, an aluminum nitride sintered body was produced. The aluminum nitride powder used had an average particle size of 0.6 μm and a specific surface area of 3.4 m ² / g. The aluminum nitride sintered body was processed to have a diameter of 330 mm and a thickness of 6 mm.

  In addition, the heating element circuit 3 was made of a stainless steel foil patterned by etching, and the electrical insulating sheet 4 was made of mica. The back plate 5 was processed tough pitch copper to have a diameter of 330 mm and a thickness of 3 mm, followed by Ni plating. In addition, the pattern of the heat generating circuit 3 was a center hot pattern having a heat generation density closer to the inner periphery than the outer periphery, as shown in FIG. These were mechanically connected using a screw provided with a bearing for absorbing thermal expansion of the two plates in the plane direction to form a heater module.

  Next, as the cooling block 2, an oxygen-free copper metal plate having a diameter of 330 mm and a thickness of 4 mm and 8 mm was prepared. Of these, a groove serving as a flow path was provided on an 8 mm copper plate, and a feed hole, a sensor, and a through hole through which a wafer support pin was inserted were provided. A copper plate having a thickness of 4 mm was subjected to the same processing except for the groove processing, and these two sheets were integrated by brazing. At that time, a part made of stainless steel was brazed as a connector to be connected to the flow path outside the system at a portion serving as the entrance / exit of the flow path.

  These heater module and cooling block 2 were attached to a container having a predetermined shape. An intervening layer 6 to be described later can be arranged on the surface of the cooling block 2 facing the back plate 5. Further, an air cylinder was attached to the cooling block 2 so as to be able to contact and separate from the back plate 5 of the heater module. Here, the roundness of the frame portion of the container was finished to 0.1 mm or less by machining.

  The heater module was set at the center of the container so that the coaxiality between the heater module and the container frame was within 0.1 mm. By doing in this way, the heat of a heater module was locally taken away by the container, and the soaking property was not inhibited. Further, the container was made of stainless steel having mechanical strength so as not to be distorted even when the heater module and the cooling block 2 were attached. Furthermore, a power supply terminal, a cable, and a temperature sensor for energizing the heater were attached.

For the intervening layer 6, a 0.5 mm thick silicone resin sheet was used. This was processed to produce five types of intervening layers 6 having different density distributions in the surface direction as shown in Table 1 below. With respect to five cases (cases 1 to 5) in which these five types of intervening layers 6 are arranged in the cooling block 2, the heater unit was evaluated by the method described later. Further, for the sake of comparison, the same evaluation was performed for a case where the intervening layer 6 is not disposed (case 6) and a case where the intervening layer 6 is disposed on the entire surface regardless of the inner and outer periphery (case 7). In Table 1, the inner peripheral portion refers to a region having a center to a diameter of 240 mm (45240 mm ² ), and the outer peripheral portion refers to a region having a diameter of 240 mm to a diameter of 328 mm (39260 mm ² ).

  First, the heater was energized with the cooling block 2 separated from the heater module, and heated to 180 ° C. In this state, a known wafer thermometer was placed on the wafer placement surface of the heater module, and the temperature distribution in the wafer surface was measured.

  When the temperature becomes stable, the cooling block 2 is brought into contact with the back plate 5 of the heater module using the air cylinder to cool, and the indication value of the temperature sensor attached to the heater module becomes 130 ° C. The cooling block 2 is separated from the heater module. Then, after reaching 130 ° C., power is applied to the heater module to stabilize the heater, and the soaking range after 30 seconds (temperature difference between the highest temperature part and the lowest temperature part of the mounting surface) is measured, Data was obtained on the correlation between the arrangement density distribution in the surface direction of the intervening layer 6 (contact density distribution between the cooling block 2 and the back plate 5) and the thermal uniformity. These results are shown in Table 1 below. In the evaluation columns of Tables 1 to 3, “◯” indicates that the thermal uniformity is superior to that of the comparative example, and “◎” indicates that it is extremely excellent.

  As can be seen from this result, in case 6 of the comparative example, after reaching 130 ° C., the in-wafer in-plane soaking range 30 seconds after applying the electric power for stabilizing the heater temperature is as large as 16.2 ° C. It was. This is because the in-plane distribution depends on the flatness of the surface facing the cooling block 2 on the heater module and the flatness of the surface facing the heater module on the cooling block 2, and these are in contact with each other. Is excessively cooled, and the region where the voids are formed is not cooled and is due to the high temperature. That is, if the flatness of the abutting surface changes due to manufacturing variation or the like, it means that the in-plane temperature distribution during and after the cooling also varies.

  Further, in the case 7 of the comparative example, the in-plane soaking range of the wafer is 6.1 ° C., and the temperature distribution of this example was center hot, so that the outer peripheral part compared to the inner peripheral part during cooling. You can see that it is cold well. This is because the cooling of the heater substrate 1 due to the contact of the cooling block 2 includes the heat transfer from the heater substrate 1 to the cooling block 2 and the heat dissipation from the heater. This is considered to be due to more heat dissipation than the part.

  On the other hand, in cases 1 to 5 in which the arrangement density of the intervening layer 6 is different between the inner and outer circumferences, a decrease in the soaking range was recognized by lowering the arrangement density of the outer circumference compared to the inner circumference. In particular, Cases 3 and 4 arranged so that the arrangement density of the outer peripheral portion was 70 to 80% by area ratio showed a very good value of 1.3 to 1.7 ° C. in the soaking range. Note that the temperature distribution at this time is neither center hot nor center cool, but the support pin supporting the object to be processed, the through hole through which the temperature sensor is inserted, and the vicinity of the through hole through which the power supply wiring for power supply is inserted are relatively It showed a low temperature.

[Example 2]
The pattern of the heating element circuit 3 is the same as that of the first embodiment except that the pattern of the heating element circuit 3 is a center cool pattern having a dense heat generation density in the outer peripheral portion as compared with the heat generation density in the inner peripheral portion as shown in FIG. In addition, five cases (cases 8 to 12) having different density distributions in the surface direction of the intervening layer 6, and a case where the intervening layer 6 is not arranged (case 13) and the intervening layer 6 are arranged on the entire surface regardless of inner and outer circumferences for comparison. The case (case 14) was evaluated. These results are shown in Table 2 below.

  As can be seen from this result, in the case 13 of the comparative example, as in the case of the center hot pattern, the soaking range is extremely large, and the temperature distribution is the flatness of the surface facing the cooling block 2 on the heater module, This depends on the flatness of the surface of the cooling block 2 facing the heater module. That is, the place where they contact each other was excessively cooled, and the region where the void was formed was not cooled and the temperature was high. In the case 14 of the comparative example, the result was the same as in the case of the center hot pattern. However, the soaking range slightly decreased compared to the center hot pattern because the surface area of the heater during cooling was particularly small. This is probably because the heat generation density at the outer periphery is designed to be high so as to compensate for heat dissipation from the large outer periphery.

  On the other hand, in the cases 8 to 12 in which the arrangement density of the intervening layer 6 is distributed on the inner and outer circumferences, a reduction in the soaking range is recognized by lowering the arrangement density of the inner circumference compared to the outer circumference. It was. In particular, for the cases 10 and 11 arranged so that the arrangement density of the inner peripheral portion was 70 to 80% in terms of area ratio, the soaking range showed a very good value of 1.2 to 1.5 ° C. Note that the temperature distribution at this time is not center hot or center cool, as in the case of the center hot pattern, a support pin for supporting the object to be processed, a through hole through which the temperature sensor is inserted, and a power supply wiring line for power supply The temperature in the vicinity of the through hole through which was inserted was relatively low.

[Example 3]
The pattern of the heating element circuit 3 is the same as that in Example 1 except that the pattern of the heating element circuit 3 is a uniform pattern having the same heat generation density at the inner peripheral portion and the outer peripheral portion as shown in FIG. 5 cases (cases 15 to 19) having different density distributions in the plane direction, a case in which no intervening layer 6 is arranged for comparison (case 20), and a case in which the intervening layer 6 is arranged on the entire surface regardless of the inner and outer circumferences (case 21) Was evaluated. These results are shown in Table 3 below.

  As can be seen from this result, the case 20 of the comparative example was almost the same as the cases 6 and 13 of the examples 1 and 2 in both the soaking range and the temperature distribution. In the case 21 of the comparative example, the results were almost the same as the cases 7 and 14 of the first and second embodiments.

  On the other hand, in cases 15 to 19 in which the arrangement density of the intervening layer 6 is different between the inner and outer circumferences, a decrease in the soaking range was recognized by lowering the arrangement density of the outer circumference compared to the inner circumference. This is assumed to be the same mechanism as in the cases 7 and 14 of the first and second embodiments. However, since heat is dissipated from the outer peripheral portion having a large surface area of the heater during cooling, the inner periphery is relatively during cooling. It has been found that the outer peripheral part cools better than the part. Therefore, it is considered that the arrangement density of the intervening layer 6 is relatively denser in the inner peripheral part than in the outer peripheral part (the outer peripheral part is sparser than the inner peripheral part), thereby maintaining the balance.

[Example 4]
In Examples 1 to 3, the arrangement density of the intervening layers 6 is made relatively dense so as to cancel out the heat density distribution of the heat generating circuit 3, that is, in a region where the heat density is relatively high in the plane. However, in a relatively low area in the plane, the arrangement density of the intervening layer 6 is made relatively sparse, so that the soaking range after applying electric power to stabilize the heater temperature after cooling is reduced. I found out.

  Here, as a result of optimizing the density distribution of the heating element circuit 3 and the arrangement density distribution of the intervening layer 6 in Examples 1 to 3 in order to further improve the thermal uniformity, the through hole through which the support pin and the temperature sensor are inserted , And the fact that the temperature in the vicinity of the through hole through which the power supply wiring is inserted is relatively low, and in addition to the density distribution of the inner and outer circumferences, the arrangement density distribution in the vicinity of the through hole described above is changed to change the temperature immediately after the temperature change. Verification was performed to improve the soaking characteristics.

  The arrangement of the intervening layer 6 is based on the structure of the case 4 in which the heating element circuit 3 is a center hot pattern in Example 1 and the arrangement density distribution of the intervening layer 6 is 100% for the inner circumference and 80% for the outer circumference. A heater module in which the density was locally changed was produced (cases 22 to 28), and the same evaluation as in Example 1 was performed. As shown in FIG. 3, the local density change location is in the vicinity of the through hole through which the temperature sensor is inserted, in the vicinity of the through hole through which the workpiece is inserted through the support pin, and in the vicinity of the through hole through which the power supply terminal and the power supply wiring are inserted. Three locations were provided.

  These three places are places where they do not come into physical contact when the cooling block 2 is brought into contact with the back plate 5. For this reason, the temperature at the location is relatively higher than that of other contact areas where no through-holes or the like are provided, which may be a factor that hinders the in-plane temperature distribution.

  And the same evaluation as Example 1, the result of measuring the soaking range after 30 seconds after applying power to the heater unit to increase and decrease the arrangement density in the vicinity of each through hole and stabilize the heater Is shown in Table 4 below. The evaluation in the evaluation column is based on the soaking range of Case 4, where ○ is superior to Case 4, ◎ is extremely superior to Case 4, and △ is Case 4. It is slightly inferior to.

  As can be seen from this result, a through hole for inserting each part is provided in the cooling block 2 that is in contact with each other, and the location is physically on the contact surface of the heater substrate 1 with the cooling block 2. Since they do not contact, it is harder to cool than other parts during cooling. Therefore, in any experiment, by increasing the arrangement density in the vicinity of the through holes, the soaking range after power application for stabilizing the temperature of the heater unit slightly decreased. Further, in case 28 in which these were combined, the soaking range after 30 seconds of power application could be greatly reduced to 0.3 ° C.

  This is because by increasing the arrangement density in the vicinity of each through-hole, it is possible to actively cool the region that is not physically contacted and difficult to cool at the time of cooling, in particular, all the vicinity of the three through-holes where this phenomenon is remarkable. It is considered that this can be offset by preliminarily cooling the portion that generates excessive heat locally after application of power, for example, the vicinity of the power supply terminal excessively in advance. . This is because the power supply terminal has a certain heat capacity and is connected to a power supply device outside the heater unit system via a power line for applying power, etc., so that it can be exposed indirectly to the outside air via this power line. To dissipate more heat. Considering such heat escape, the heat generation pattern in the vicinity of the power supply terminal is prepared in advance by increasing the heat generation density. Therefore, it is possible to increase the arrangement density of the intervening layers 6 around this part in terms of heat equalization. It is thought that it was effective.

DESCRIPTION OF SYMBOLS 1 Heater board 2 Cooling block 3 Heat generating body circuit 4 Electrical insulation sheet 5 Back plate 6 Interposition layer 10 Heater unit

Claims (3)

  In a heater unit including a heater substrate having a mounting surface for mounting and processing an object to be processed and a cooling block for cooling the heater substrate, a constant is provided between the heater substrate and the cooling block. There is an intervening layer having a height, and the intervening layer has a density such that a region that becomes a relatively high temperature portion when the heater substrate is heated has a higher density than a region that becomes a relatively low temperature portion. A heater unit characterized by being distributed.   2. The heater according to claim 1, wherein the intervening layer is disposed at a relatively high density in the vicinity of a counterbore or a through-hole formed on a surface facing the heater substrate in the cooling block. unit.   3. The heater unit according to claim 1, wherein the cooling block contacts the heater substrate when the heater substrate is cooled and is separated from the heater substrate when the heater substrate is heated.

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