JP6593413B2 - Heater unit for wafer heating - Google Patents

Description

  The present invention relates to a heater unit that heats from the lower surface side with a semiconductor wafer placed thereon.

  In semiconductor manufacturing equipment for manufacturing semiconductor devices such as LSI and memory, a series of processes such as film formation by CVD or sputtering, photolithography such as resist application, exposure and development, etching for patterning, etc. on a semiconductor wafer Thin film processing consisting of processes is performed. In these thin film processes, the semiconductor wafer is generally processed while being heated to a predetermined temperature. For example, in a coater / developer apparatus in which photolithography is performed, a semiconductor wafer as an object to be processed is placed and heated from its lower surface. A heater unit for heating a wafer, also called a susceptor, is used.

  For example, as disclosed in Patent Document 1, the wafer heating heater unit supports a wafer mounting table made of a ceramic disk-shaped member having a flat wafer mounting surface on the upper surface, and supports this from the lower surface side. A heating support circuit such as an electric heating coil or a patterned metal thin film is embedded in the wafer mounting table in parallel with the wafer mounting surface. A pair of electrode terminals provided on the lower surface side of the wafer mounting table are electrically connected to both ends of the heat generating circuit, and the heat generating circuit is connected from an external power source via the pair of electrode terminals and the lead wires. Is supplied with power.

  In the above-described heater unit for heating a wafer, it is required to heat the semiconductor wafer uniformly over the entire surface by improving the heat uniformity on the wafer mounting surface so that the quality of the semiconductor device as a product does not vary. ing. Therefore, the circuit pattern of the heat generating circuit is made minute so as not to cause temperature unevenness, or the temperature is individually controlled for each of a plurality of heating zones (multi-zones) defined on the wafer mounting surface. A heating circuit that extends in parallel with the wafer mounting surface is arranged in each of the plurality of heating zones to supply power individually.

JP 2003-17224 A

  Although it becomes possible to individually control the temperature of the plurality of heating zones by arranging a plurality of heating circuits in the plurality of heating zones defined on the wafer mounting surface as described above, the heating zones are arranged in each heating zone. In a control system that controls the amount of heat generated by the heat generation circuit with voltage or current, generally, one temperature sensor is provided for each heating zone as a temperature detector. Therefore, when the area of the heating zone increases, heating is performed with one temperature sensor. It may be difficult to properly detect the temperature of the zone, and the temperature may not be controlled well.

  Conventionally, the adverse effect on the thermal uniformity of the wafer mounting surface due to the above temperature detection problem was so small that it could be ignored, but with the recent miniaturization of semiconductor devices, More precise control is required for the temperature of the wafer mounting surface on which the semiconductor wafer is mounted. Therefore, the above-mentioned problems that have not been regarded as problems so far are becoming apparent. The present invention has been made in view of such circumstances, and in each of a plurality of heating zones defined on the wafer mounting surface, the temperature of the wafer mounting surface is appropriately detected and controlled. It is an object of the present invention to provide a wafer heating heater unit capable of enhancing thermal properties.

  In order to achieve the above object, a heater unit for heating a wafer according to the present invention includes a disk-shaped wafer mounting table having a wafer mounting surface on which a semiconductor wafer is mounted, and a disk that supports the wafer mounting table. A wafer heating heater unit having a circular support plate, and a circular thin film heating module sandwiched between the wafer mounting table and the supporting plate, the heating module being parallel to the wafer mounting surface And the plurality of heating zones defined on the wafer mounting surface by the plurality of heating circuits are adjacent to each other in the radial direction of the wafer mounting surface. Also in the zones, the separation distance of the center position of each heating zone is 50% or more of the longest distance from the center position of each heating zone to the boundary of the heating zone. There.

  According to the present invention, it is possible to appropriately detect and control the temperature in each of the plurality of heating zones defined on the wafer mounting surface, so that it is possible to improve the thermal uniformity of the wafer mounting surface. Become.

It is a longitudinal cross-sectional view of one specific example of the heater unit for wafer heating which concerns on this invention. It is a top view which shows the division | segmentation pattern of the some heating zone of the wafer mounting surface demarcated by the some heat generating circuit which the heater unit for wafer heating of FIG. 1 has. FIG. 3 is a plan view showing the relationship between the distance between the center positions of adjacent heating zones and the longest distance from the center position of each heating zone to the zone boundary in the division pattern of FIG. 2. It is a top view which shows the division pattern of the several heating zone defined on the wafer mounting surface of the heater unit for wafer heating of the comparative examples 1 and 2 of this invention.

  First, embodiments of the present invention will be listed and described. An embodiment of a heater unit for heating a wafer according to the present invention includes a disk-shaped wafer mounting table provided with a wafer mounting surface on which a semiconductor wafer is mounted, and a disk-shaped support plate that supports the wafer mounting table. A heater unit for heating a wafer having a circular thin film heating module sandwiched between the wafer mounting table and the support plate, wherein the heating module extends in parallel to the wafer mounting surface. The plurality of heating zones defined on the wafer mounting surface by the plurality of heating circuits are any heating zones adjacent to each other in the radial direction of the wafer mounting surface, The separation distance of the center position of each heating zone is 50% or more of the longest distance from the center position of each heating zone to the boundary of the heating zone. As a result, the temperature can be appropriately detected and controlled in each of the plurality of heating zones defined on the wafer placement surface, so that it is possible to improve the thermal uniformity of the wafer placement surface.

  In the embodiment of the heater unit for heating a wafer of the present invention, the plurality of heating zones include a central fan-shaped heating zone obtained by dividing the circular central portion into three equal parts in the circumferential direction, and an annular peripheral portion in the heating module. It is preferable to include a peripheral fan-shaped heating zone divided into six equal parts in the direction and an intermediate fan-shaped heating zone obtained by dividing the annular intermediate part between the circular central part and the annular peripheral part into six equal parts in the circumferential direction. Thereby, the thermal uniformity of the mounting surface on which the semiconductor wafer is mounted can be further enhanced. Moreover, in the embodiment of the heater unit for heating a wafer according to the present invention, the semiconductor is between the heating zones adjacent in the circumferential direction and / or between the heating zones adjacent in the radial direction among the plurality of heating zones. An insertion hole for a lift pin of the wafer is preferably provided. Thereby, the bad influence to the thermal uniformity of the mounting surface by the insertion hole for lift pins can be suppressed.

  Next, a specific example of the wafer heating heater unit of the present invention will be described. As shown in FIG. 1, a heater unit 10 for heating a wafer according to a specific example of the present invention includes a disk-shaped wafer mounting table 11 having a wafer mounting surface 11a on which a semiconductor wafer W is mounted on the upper surface, The wafer mounting table 11 has a disk shape having an outer diameter substantially equal to that of the wafer mounting table 11. The supporting plate 12 supports the wafer mounting table 11 from the lower surface to the entire surface, and the wafer mounting table 11 and the supporting plate 12. And a heat generating module 13 in the form of a circular thin film having an outer diameter substantially equal to that of the wafer mounting table 11. The wafer heating heater unit 10 is supported by a plurality of columnar legs 20 provided on the lower surface side of the support plate 12.

  The wafer mounting table 11 is preferably made of a material having a high thermal conductivity so as to realize extremely high temperature uniformity, that is, high heat uniformity over the entire surface of the wafer mounting surface 11a, such as copper or aluminum. Metal is more preferred. The material of the wafer mounting table 11 may be a ceramic (ceramic composite) having a high rigidity (Young's modulus) such as silicon carbide, aluminum nitride, Si—SiC, or Al—SiC. In addition, it is not necessary to increase the thickness of the wafer mounting table 11 for the purpose of preventing warpage of the wafer mounting surface 11a, so that the heat capacity can be reduced, and thus the temperature raising / lowering speed can be increased.

  The material of the support plate 12 is also preferably a ceramic or a ceramic composite such as silicon carbide, aluminum nitride, Si—SiC, or Al—SiC having high rigidity (Young's modulus). In particular, when the material of the wafer mounting table 11 is metal, the wafer mounting table 11 and the support plate 12 are overlapped and mechanically coupled with each other with the heat generating module 13 interposed therebetween, as described later. Since the warpage can be suppressed, the heater unit 10 having both high heat uniformity and flatness on the wafer mounting surface 11a can be realized.

  It is preferable that the wafer mounting table 11 and the support plate 12 are mechanically coupled to each other by screwing or the like. In particular, when the wafer mounting table 11 and the support plate 12 are made of different materials, the wafer mounting table 11 and the support plate 12 can be freely thermally expanded in the direction of the wafer mounting surface 11a according to the respective temperatures. For example, a male screw (not shown) is inserted from below into a screw hole (not shown) penetrating the support plate 12 in the thickness direction, and a female screw portion (not shown) provided on the lower surface side of the wafer mounting table 11 is inserted. And a bearing (not shown), for example, is interposed between the seat surface of the male screw and the lower surface of the support plate 12 serving as the contact portion. In this case, also in the heat generating module 13, the insertion hole of the female screw portion is provided at a position corresponding to the screw hole of the support plate 12.

  Here, the screwing portion is preferably arranged outside the effective diameter of a heat generating circuit described later. By doing in this way, it is possible to realize a mounting table with high temperature uniformity in which local cool spots hardly occur. Moreover, when arrange | positioning the said screwing part in the effective diameter of a heat generating circuit, it arrange | positions between the heating zones adjacent to the circumferential direction among several heating zones, and / or between the heating zones adjacent to a radial direction. In addition, it is preferable that the segmented pattern be axisymmetric with respect to the radial line segment of the wafer mounting surface passing through the arrangement position, thereby suppressing deterioration in temperature uniformity due to the screwing portion. it can. More preferably, the screwing portion is located on the same radial line segment as the lift pin insertion hole described above, and the segmented pattern is axisymmetric with respect to the line segment. As described above, when there are singularities such as mechanical parts and electrical parts that interfere with any or all of the mounting table, heating unit, and support plate, these singularities are placed outside the effective diameter of the heating circuit. Alternatively, in the case of within the effective diameter, the desired function can be exhibited without impairing the temperature uniformity by disposing it at a position that is between adjacent heating zones and that is a symmetrical line of the division pattern. The effective diameter of the heat generating circuit is a diameter of a circular area in the wafer mounting surface 11a where a heat generating circuit 13a described later is arranged directly below.

  The heat generating module 13 sandwiched between the wafer mounting table 11 and the support plate 12 has a plurality of heat generating circuits 13a extending on a surface parallel to the wafer mounting surface 11a. The plurality of heat generating circuits 13a are covered with an insulator so as to be electrically insulated from the wafer mounting table 11 and the support plate 12, and the heat generating module 13 having such a configuration includes, for example, a stainless steel foil or the like. A plurality of heat generating circuits 13a can be formed by patterning the conductive metal foil by etching or laser processing, and then sandwiched by a heat resistant insulating sheet such as a polyimide sheet from above and below.

  Alternatively, if it is difficult to handle the heat generating circuit 13a because the line width of the circuit pattern of the heat generating circuit 13a is narrow or the thickness of the conductive metal foil used for the heat generating circuit 13a is difficult, the conductive pattern before the patterning process is used. The conductive polyimide foil and a heat-resistant insulating sheet such as a polyimide sheet for electrical insulation are preliminarily superposed and thermocompression bonded, and after this thermocompression bonding, only the conductive metal foil is patterned by etching, etc. The film and the pattern foil (that is, the foil-like heat generating circuit 13a) are integrated, and a polyimide film is further superposed on the integrated foil-like heat generating circuit 13a, followed by thermocompression bonding. May be produced.

  As described above, by providing the heat generating module 13 with a plurality of heat generating circuits 13a extending in parallel to the wafer mounting surface 11a, the wafer mounting surface 11a can be divided into a plurality of heating zones. There is no particular limitation on the division pattern of the plurality of heating zones defined by the plurality of heating circuits 13a, but the disk-shaped wafer mounting table 11 generally radiates heat from the peripheral portion having a larger surface area than the central portion. For this reason, the peripheral edge tends to be locally low in a steady state. On the other hand, when a semiconductor wafer is mounted on a mounting table, since the outer diameter of the mounting table is generally larger than the wafer diameter, the center of the mounting table is a concentric center cool type temperature that is lower than the outer periphery. Distribution occurs. Thereafter, the temperature of the mounting table is raised to a predetermined temperature by the action of the control system, but since it is affected by the above temperature distribution, the transient temperature distribution of the semiconductor wafer also becomes a concentric center cool. In order to correct such a center-cool type temperature distribution, it is preferable to divide the heating zone section pattern into concentric circles in the radial direction. Further, since a load lock or the like is provided on the wall surface of the vacuum chamber on which the heater unit 10 is mounted, the environment around the wafer mounting table 11 is not uniform in the circumferential direction. Therefore, as shown in FIG. 2, it is preferable to divide the wafer mounting surface 11a into concentric circles, and then further divide the wafer mounting surface 11a evenly in the circumferential direction.

  That is, in the divided pattern of the plurality of heating zones shown in FIG. 2, the wafer mounting surface 11a has a circular central portion A, an annular intermediate portion B outside the circular central portion A, and an outer portion of the annular intermediate portion B. It is divided concentrically into an annular peripheral edge C. Further, the circular central part A is divided into three equal parts in the circumferential direction as central fan-shaped heating zones A1 to A3, and the annular intermediate part B is an intermediate fan-shaped part. The circumferential zones C are equally divided into six heating zones B1 to B6, and the annular peripheral edge C is equally divided into six circumferentially fan-shaped heating zones C1 to C6.

  Furthermore, in the heater unit 10 of one specific example of the present invention, the heating zone composed of the 15 zones divided as described above is the heating zone adjacent to each other in the radial direction of the wafer mounting surface 11a. The separation distance between these two center positions is 50% or more of the longest distance from the center position of each heating zone to the zone boundary. Here, the center position of the heating zone can be defined as a geometric center point in the case of a general shape such as a circle or a triangle, and in the case of a line-symmetric shape, a symmetrical line segment serving as the axis of symmetry. Can be defined as an intermediate point. For example, in the case of a fan-shaped heating zone as shown in FIG. 2, the intermediate position in the circumferential direction and the intermediate point in the radial direction become the center position.

  The relationship between the distance between the center positions of adjacent heating zones and the longest distance from the center position of each heating zone to the zone boundary will be described in more detail with reference to FIG. First, the relationship between the circular central portion A and the annular intermediate portion B adjacent to each other in the radial direction of the wafer mounting surface 11a will be examined. Among the circular central portion A, the heating zones in which the central fan-shaped heating zone A1 is adjacent in the radial direction are the two intermediate fan-shaped heating zones B1 and B2.

Of these, the relationship between the central portion fan heating zone A1 and the intermediate portion diverging heating zone B1, the distance of the center position O _B1 of the center position O _A1 and the intermediate portion diverging heating zone B1 of the central fan heating zone A1 is a line _{This is} the distance of the minute _LA1B1 . In the central sector heating zone A1, the longest straight line distance from the center position O _A1 to the zone boundary is the distance of the line segment L _A1 connecting the center position O _A1 and P _A1 corresponding to the corner of the sector. It is. On the other hand, in the intermediate sector heating zone B1, the longest straight line distance from the center position O _B1 to the zone boundary is the distance of the line segment L _B1 connecting the center position O _B1 and P _B1 corresponding to the corner of the sector. It is.

As can be seen from FIG. 3, compared to the distance of the line segment L _A1B1 a distance of the distance and both the center position of the line segment L _A1, 50% of the length of the distance of the line segment L _A1, said It is shorter than the distance of line segment L _A1B1 . Also, compared to the distance of the line segment _{L A1B1} a distance of the distance and both the center position of the line segment _{L B1,} 50% of the length of the distance of the line segment _{L B1,} the above line segment _{L A1B1} Shorter than the distance. In addition, the division pattern shown in FIG. 3 is axisymmetric with respect to the boundary line between the intermediate fan-shaped heating zones B1 and B2, and thus the adjacent central fan-shaped heating zone A1 and intermediate fan-shaped heating zone B2 This relationship is also the same as the relationship between the central fan-shaped heating zone A1 and the intermediate fan-shaped heating zone B1. Further, the relationship between the central fan-shaped heating zone A2 and the intermediate fan-shaped heating zones B3 and B4 and the relationship between the central fan-shaped heating zone A3 and the intermediate fan-shaped heating zones B5 and B6 are the same as the above-described central fan-shaped heating zone A1. This is the same as the relationship with the intermediate fan-shaped heating zone B1.

The same can be said for the relationship between the annular intermediate portion B and the annular peripheral portion C adjacent to each other in the radial direction of the wafer mounting surface 11a. That is, the heating zone adjacent to the intermediate fan heating zone B1 in the annular intermediate portion B is the peripheral fan heating zone C1. Distance of the center position _{O C1} of the center position _{O B1} and periphery fan heating zone C1 of the intermediate portion diverging heating zone B1 is the distance of the line segment _{L B1C1.} In the intermediate fan-shaped heating zone B1, as described above, the longest straight line distance from the center position O _B1 to the zone boundary is a line connecting the center position O _B1 and P _B1 corresponding to the fan-shaped corner. This is the distance of the minute L _B1 . On the other hand, the periphery fan heating zone C1, the longest linear distance from the center position O _C1 to the zone boundary, the distance of the line segment L _C1 connecting the P _C1 corresponding to the corners of the fan and the center position O _C1 It is.

As it can be seen from FIG. 3, compared to the distance of the line segment L _B1C1 a distance of the distance and both the center position of the line segment L _B1, 50% of the length of the distance of the line segment L _B1, the above It is shorter than the distance of the line segment L _B71C1 . Also, compared to the distance of the line segment _{L B1C1} a distance of the distance and both the center position of the line segment _{L C1,} 50% of the length of the distance of the line segment _{L C1,} the above line segment _{L B1C1} Shorter than the distance. It should be noted that the relationship between the intermediate fan heating zone B2 and the peripheral fan heating zone C2, the relationship between the intermediate fan heating zone B3 and the peripheral fan heating zone C3, the intermediate fan heating zone B4 and the peripheral fan heating zone C4, In the relationship between the intermediate fan heating zone B5 and the peripheral fan heating zone C5, and the relationship between the intermediate fan heating zone B6 and the peripheral fan heating zone C6, the above-described intermediate fan heating zone B1. And the peripheral fan-shaped heating zone C1.

  The wafer heating heater unit 10 of one specific example of the present invention has the above-described division pattern, so that the temperature of the mounting surface 11a can be more precisely controlled. The heater unit 10 for heating a wafer according to a specific example of the present invention may include an insertion hole for a lift pin of a semiconductor wafer between the heating zones adjacent in the circumferential direction among the plurality of heating zones. Good. For example, FIG. 2 shows an example in which three lift pin insertion holes Q1 to Q3 are provided between the central fan-shaped heating zones A1 and A2, between A2 and A3, and between A3 and A1, respectively. It is shown. Thus, by providing the lift pin insertion hole between the heating zones adjacent in the circumferential direction, it is possible to suppress the adverse effect of the thermal uniformity on the placement surface 11a due to the insertion hole. Alternatively, the lift pin insertion holes may be provided between the heating zones adjacent in the radial direction, or between the heating zones adjacent in the circumferential direction and between the heating zones adjacent in the radial direction. May be.

  There is no particular limitation on the circuit pattern of a heating circuit (not shown) provided in each heating zone, and various circuit patterns can be provided. For example, a circuit pattern formed in a single stroke can be formed by a plurality of concentric curved conductive portions and a linear conductive portion connecting adjacent ones of the curved conductive portions. In this case, two electrode terminals (not shown) are connected to both ends of the heat generating circuit.

  The plurality of heat generating circuits may have different heat generation densities for each heating zone. For example, as described above, since the outer diameter of the mounting table is generally larger than the wafer diameter, when a semiconductor wafer is mounted on the mounting table, the central portion of the mounting table has a concentric center cooler at a lower temperature than the outer peripheral portion. A temperature distribution of the mold occurs. Thereafter, the temperature of the mounting table is raised to a predetermined temperature by the action of the control system, but since it is affected by the above temperature distribution, the transient temperature distribution of the semiconductor wafer also becomes a concentric center cool. In order to correct such a center-cool type temperature distribution, by designing the heat generation density of the central fan-shaped heating zones A1 to A3 to be high, the transient temperature uniformity during wafer mounting can be further improved. . A method of increasing the heat generation density can be realized by reducing the pitch of the circuit pattern of the heat generating circuit or by narrowing the width of the conductive line constituting the heat generating circuit.

  In addition, in the heat generating module 13, the effective area of the heat generating circuit with respect to the entire area parallel to the wafer mounting surface 11a (that is, the space between the heating zones adjacent to each other, the screw hole from the total area of the heat generating module 13). And the ratio of the effective heat generation area is preferably 80% or more.

  The heater unit 10 for heating a wafer according to a specific example of the present invention corresponds to the above-described center position of a temperature measuring sensor (not shown) including a temperature measuring element whose resistance value is adjusted in each of a plurality of heating zones. It is preferable that the heating circuit in the heating zone is individually controlled based on the detection value of each temperature sensor while being provided at the position. As a result, the mounting surface 11a can be locally heated, so that, for example, even if the mounting surface 11a is partially cooled by opening / closing a load lock or the like, good thermal uniformity is maintained. Is possible. For example, the temperature measuring sensor is provided with a counterbore hole having a size that can accommodate the temperature measuring sensor on the lower surface side of the wafer mounting table 11, and an adhesive is applied to the bottom surface of the wafer mounting table 11 so that the temperature measuring sensor is bonded and fixed. The temperature can be detected well.

  Returning to FIG. 1 again, the wafer heating heater unit 10 according to an embodiment of the present invention is provided with a cooling unit 30 below the support plate 12. The cooling unit 30 is movable cooling that can reciprocate between a contact position that contacts the lower surface side of the support plate 12 as indicated by a one-dot chain line and a spaced position that is separated from the support plate 12 as indicated by a solid line. A plate 31 and a fixed cooling stage 32 that abuts when the movable cooling plate 31 is in the separated position. The material of the movable cooling plate 31 and the fixed cooling stage 32 is selected from the group consisting of copper, aluminum, nickel, magnesium, titanium having high thermal conductivity, an alloy mainly containing at least one of these, or stainless steel. It is preferable to do.

  The fixed cooling stage 32 has a refrigerant flow path 32a in which an antifreeze liquid such as a fluorine-based refrigerant cooled by a cooling device such as a chiller (not shown), a refrigerant such as air, and general water is circulated. The form of the refrigerant flow path is not particularly limited. For example, a metal pipe such as Cu is provided as a refrigerant flow path on the lower surface side of the metal plate-like member, and a stainless steel joint is provided at both ends of the metal pipe. In addition to the attachment, the pressing plate and the plate-like member can be mechanically coupled with a screw or the like in a state where the metal pipe is pressed against the plate-like member with the holding plate.

  Alternatively, in order to obtain higher thermal efficiency, a structure in which, for example, a spiral counterbore groove is provided on the lower surface side of the metal plate-like member, and a metal pipe for circulating the refrigerant formed in a spiral shape in the counterbore groove is installed. Good. In this case, in order to maintain good heat transfer between the metal pipe and the cooling plate, it is preferable to bond and fix the surface of the metal pipe and the inner surface of the counterbored groove with a caulking material, a sealant, an adhesive, or the like. Alternatively, two plate-like members of substantially the same shape made of the same material are prepared, and a groove to be a flow path is formed by machining on one or both surfaces of the two members so that the flow path side faces each other. For example, a structure in which a plurality of plate-like members are overlapped and integrated by a joining method such as brazing may be used.

  The movable cooling plate 31 is attached to an elevating mechanism 33 composed of an air cylinder or the like. Accordingly, by operating the elevating mechanism 33, the fixed cooling plate 31 can be reciprocated between the contact position described above and the separation position. Instead of using the movable cooling plate 31, the cooling stage 32 itself having the refrigerant flow path may be reciprocated between a position where it abuts on the lower surface side of the support plate 12 and a position where it is separated from the lower surface side. .

  An intervening layer (not shown) may be provided on the upper surface of the movable cooling plate 31, the upper surface of the fixed cooling stage 32, and / or the lower surface of the support plate 12. This intervening layer preferably has cushioning properties (flexibility) in the thickness direction, and preferably has heat resistance. Furthermore, it is preferable to have a high thermal conductivity of, for example, 1 W / m · K or more. Examples of such a material include foam metal, metal mesh, graphite sheet, or resin sheet such as fluororesin, polyimide resin, or silicone resin. In addition, it becomes possible to make thermal resistance smaller by containing thermal conductive fillers, such as carbon, in said resin sheet. In addition, it is preferable that the wafer heating heater unit 10 and the cooling unit 30 of one specific example of the present invention are preferably housed in a container 40 made of stainless steel.

  As mentioned above, although one embodiment was mentioned and demonstrated about the heater unit for wafer heating of this invention, this invention is not limited to this embodiment, It implements in the various aspects of the range which does not deviate from the main point of this invention. It is possible. That is, the technical scope of the present invention extends to the claims and their equivalents.

[Example 1]
A wafer heating heater unit 10 having a cooling unit 30 provided below as shown in FIG. 1 was produced, and the thermal uniformity of the wafer mounting surface 11a was evaluated. Specifically, first, a disk-shaped copper plate having a diameter of 320 mm and a thickness of 3 mm was prepared as the wafer mounting table 11. Fifteen counterbore holes are formed at the center position, which will be described later, of the surface opposite to the wafer mounting surface 11a of the copper plate, and each of these counterbore holes is made of a ceramic (W2 mm × D2 mm × H1 mm) measurement. The temperature element was bonded and fixed using a silicone adhesive.

  Next, a disc-shaped Si—SiC plate having a diameter of 320 mm and a thickness of 3 mm was prepared as the support plate 12. The Si-SiC plate was provided with a lead wire for the temperature measuring element and a through hole for insertion such as a screw to be described later. Next, as a resistance heating element to be a plurality of heat generating circuits 13a of the heat generating module 13, a circuit pattern of the plurality of heat generating circuits 13a is formed by etching on a stainless steel foil having a thickness of 20 μm, and a power supply cable is connected to each of both end portions thereof. Then, the resistance heating element was covered with a polyimide sheet having a thickness of 50 μm from both the upper and lower surfaces and thermocompression bonded to prepare a heating module 13 in the form of a circular film having a diameter of 320 mm.

  Here, the plurality of heating zones in which the plurality of heat generating circuits 13a of the heat generating module 13 are respectively provided have the division pattern of FIG. Specifically, with respect to the center point of the circular heat generating module 13, three concentric circles of φ120 mm, φ246 mm, and φ302 mm are divided into a circular central portion A, an annular intermediate portion B, and an annular peripheral portion C, and further, φ120 mm The circular central portion A is divided into three equal parts in the circumferential direction to form central fan-shaped heating zones A1 to A3, and the annular intermediate part B having an outer diameter of φ246 mm and an inner diameter of φ120 mm is divided into six equal parts in the circumferential direction. To B6, an annular peripheral edge C having an outer diameter of φ302 mm and an inner diameter of φ246 mm was equally divided into six in the circumferential direction to form peripheral fan-shaped heating zones C1 to C6. The temperature measuring elements were arranged at the center positions of the respective sections so that the fifteen heating circuits 13a provided in the heating zones of the total 15 sections were individually controlled. Note that the power supply cable of the heat generation circuit is also drawn out for each section.

  The heat generating module 13 produced in this way is sandwiched between the wafer mounting table 11 and the support plate 12, and a screw is inserted into a through hole provided in the support plate 12 in advance to be screwed into the wafer mounting table 11. did. As a result, a wafer heating heater unit 10 in which the wafer mounting table 11 and the support plate 12 were mechanically coupled to each other with the heat generating module 13 interposed therebetween was produced. In addition, the fastening screw provided with the bearing on the seat surface was used for said screw so that the wafer mounting base 11 and the support plate 12 might not deform | transform by the thermal expansion amount difference. Three fastening screws were provided for PCD 120 mm and six for PCD 310 mm. In addition, in order to suppress the heat escape from the lead wire of the temperature measuring element, the lead wire of the temperature measuring element taken out from the support plate 12 is bonded and fixed with a silicone resin in a state of being in contact with the support plate 12 for a length of 30 mm. did.

  Next, as a cooling unit 30 provided below the wafer heating heater unit 10, a disk-shaped aluminum alloy plate having a diameter of 320 mm × a thickness of 12 mm for the movable cooling plate 31 and a diameter of 320 mm for the fixed cooling stage 32. X A disk-shaped aluminum alloy plate having a thickness of 12 mm was prepared. In the aluminum alloy plate for the movable cooling plate 31, a flexible silicone sheet is disposed on the upper surface side in contact with the support plate 12 so that the entire surface of the support plate 12 and the movable cooling plate 31 are in contact with each other. . On the other hand, a phosphorus-deoxidized copper pipe having an outer diameter of 6 mm and a wall thickness of 1 mm for the refrigerant flow path 32a was attached to the lower surface of the aluminum alloy plate for the stationary cooling stage 32 using screws. Then, joints for supplying and discharging the refrigerant were attached to both ends of the copper pipe.

  Both aluminum alloy plates as the cooling unit 30 thus produced were provided with through-holes through which the feeding cable, the lead wires of the temperature measuring element, and the legs 20 standing from the bottom of the container 40 described later are inserted. . Further, the aluminum alloy plate for the fixed cooling stage 32 was provided with a through hole through which the rod of the elevating mechanism 33 composed of an air cylinder of the movable cooling plate 31 was inserted. The cooling unit 30 was installed in a stainless steel container 40 having a wall having a wall thickness of 1.5 mm and having an open top. The elevating mechanism 33 is attached to the lower side of the fixed cooling stage 32, the rod is inserted into the above-described through hole for inserting the rod, and the movable cooling plate 31 is attached to the tip thereof. In this way, the heater unit 10 for heating the wafer of the sample 1 provided with the cooling unit 30 was produced. The distance between the lower surface of the support plate 12 and the upper surface of the movable cooling plate 31 when the rod of the elevating mechanism 33 was retracted was 10 mm.

  For comparison, the same as the sample 1 except that the segment pattern of the heat generating module sandwiched between the wafer mounting table 11 and the support plate 12 is changed to the segment pattern of FIGS. 4A and 4B instead of FIG. Thus, a heater unit for heating the wafer of Samples 2 and 3 equipped with a cooling unit was prepared. That is, in the heating module of the heater unit for heating the wafer of sample 2, three concentric circles of φ95 mm, φ246 mm, and φ302 mm with respect to the center point are arranged in a circular central portion D, an annular intermediate portion E, and an annular peripheral portion F. The circular central portion D and the annular intermediate portion E are not divided in the circumferential direction, but are used as a circular heating zone and an annular heating zone, respectively, and only the annular peripheral portion F having an outer diameter of φ302 mm and an inner diameter of φ246 mm is 4 in the circumferential direction. To obtain peripheral edge fan-shaped heating zones F1 to F4. A temperature measuring element was provided at the central position of each of the six heating zones. However, for the annular intermediate portion E, a temperature measuring element was provided at one place on the circumference of φ151 mm with respect to the center point of the heat generating module.

  On the other hand, in the heat generating module of the heater unit for heating the wafer of sample 3, the circular central part G, the inner annular intermediate part H, and the outer side are formed by four concentric circles of φ95 mm, φ171.5 mm, φ246 mm, and φ302 mm with respect to the center point. It is divided into an annular intermediate portion I and an annular peripheral edge portion J, and the inner annular intermediate portion H having an outer diameter of φ171.5 mm and an inner diameter of φ95 mm is equally divided into two in the circumferential direction to form inner intermediate fan-shaped heating zones H1 to H2. The outer annular intermediate portion I having an outer diameter φ246 mm and an inner diameter φ171.5 mm is equally divided into four in the circumferential direction to form outer intermediate fan-shaped heating zones I1 to I4, and an annular peripheral portion J having an outer diameter φ302 mm and an inner diameter φ246 mm is 8 in the circumferential direction. Equally divided into peripheral fan heating zones J1 to J8. A temperature measuring element was provided at the center position of each of the heating zones of a total of 15 sections. Table 1 shows a summary of the division patterns of the plurality of heating zones in the heater units of Samples 1 to 3.

  First, the flatness of the wafer mounting surface 11a was measured with a commercially available three-dimensional measuring device for the heater units of Samples 1 to 3 prepared above. Next, each of the heater units of Samples 1 to 3 was supplied with power to the plurality of heat generating circuits 13a and heated from room temperature to 110 ° C., and then held for 1 hour while controlling the temperature at a set temperature of 110 ° C. Thereafter, a commercially available wafer thermometer with a temperature sensor embedded therein was placed on the wafer placement surface 11a, and a soaking range, which is the difference between the maximum temperature and the minimum temperature in the wafer placement surface 11a, was measured. The results are shown in Table 2 below.

  As can be seen from the results in Table 2, the soaking range of the heater unit of Sample 2 was 0.17 ° C., and the soaking range of the heater unit of Sample 3 was 0.21 ° C. According to the detailed temperature distribution, the sample 2 has a maximum temperature and a minimum temperature in the heating zone of the annular intermediate portion E, and the vicinity of the bolt that fastens the wafer mounting table 11 and the support plate 12 is a low temperature region. It was. On the other hand, in the sample 3, one heating zone in the outer annular intermediate portion I was a high temperature region.

  When the output to the heating circuit of the heater unit of the sample 3 is confirmed, there is no output in one heating zone of the outer annular intermediate portion I, which has been in a high temperature range, and the heating of the inner annular intermediate portion H adjacent thereto is not performed. The output to the zone was relatively large. This is because the center positions of the heating zones adjacent to each other are too close to the size of each heating zone. Specifically, the separation distance between these two center positions is the center of each heating zone. Since it is less than 50% of the longest distance from the position to the zone boundary, it is greatly affected by the heat generation circuit of the adjacent inner annular intermediate portion H and reaches the set temperature or higher even if it is not output at the outer annular intermediate portion I It is thought that it was due to what was done. That is, it is inferred that there was interference in temperature control between adjacent heating zones.

  On the other hand, the heater unit of sample 1 has a soaking range of 0.06 ° C., which is the longest distance from the center position of each heating zone to the zone boundary. Since it was 50% or more of the distance, the specific temperature distribution due to the local temperature decrease confirmed in Samples 2 and 3 and the interference of temperature control between adjacent heating zones was not confirmed. Furthermore, the temperature around the fastening bolt that fastens the wafer mounting table 11 and the support plate 12 was not specific. This is because the position of the fastening bolt is arranged on the boundary between the heating zone of the circular central portion A and the heating zone of the annular intermediate portion B on the outer peripheral side, thereby dispersing the influence of the fastening bolt in a plurality of heating zones. It is presumed that this was done.

[Example 2]
Except that the material of the wafer mounting table 11 is changed to Si—SiC instead of copper, the heater units of the samples 4 to 6 are manufactured in the same manner as the samples 1 to 3 of the first embodiment, and the same as the first embodiment. Was evaluated. The results are shown in Table 3 below together with the flatness of the wafer mounting table 11.

  It can be seen from Table 3 that there is a tendency similar to that in Example 1. Further, as compared with Example 1, all of the heater units of Samples 4 to 6 were slightly improved in heat uniformity. This is because the wafer mounting table 11 is replaced with highly rigid Si—SiC, so that the flatness of the wafer mounting table 11 is stabilized, and the distance between the wafer mounting surface 11a and the wafer is uniform over the entire surface. This is probably due to the fact that

DESCRIPTION OF SYMBOLS 10 Heater unit for wafer heating 11 Wafer mounting base 11a Wafer mounting surface 12 Support plate 13 Heat generating module 13a Heat generating circuit 20 Leg 30 Cooling unit 31 Movable cooling plate 32 Fixed cooling stage 32a Refrigerant flow path 33 Elevating mechanism 40 Container A Circular central part A1 to A3 Central part fan-shaped heating zone B Annular intermediate part B1 to B6 Intermediate part fan-shaped heating zone C Annular peripheral part C1 to C6 Peripheral part fan-shaped heating zone L _A1 , L _B1 , L _C1 , L _A1B1 , L _B1C1 line min _{O A1,} O B1, O _C1 center position _{P A1,} P B1, insertion _{P C1} corner Q1~Q3 lift pin hole D circular central portion E annular middle portion F peripheral annular portion F1~F4 periphery fan heating zone G circular Central part H Inner ring intermediate part H1-H2 Inner intermediate part fan-shaped heating zone I Outer ring intermediate part I1-I Outer intermediate portion diverging heating zone J annular periphery J1~J8 periphery fan heating zones W semiconductor wafer

Claims (3)

A disk-shaped wafer mounting table having a wafer mounting surface on which a semiconductor wafer is mounted, a disk-shaped supporting plate that supports the wafer mounting table, and the wafer mounting table and the support plate A heater unit for heating a wafer having a circular thin film heat generating module sandwiched between,
The heat generating module includes a plurality of heat generating circuits extending in parallel to the wafer mounting surface and a heat-resistant insulating sheet sandwiching the plurality of heat generating circuits, and is defined on the wafer mounting surface by the plurality of heat generating circuits. Each of the plurality of heating zones has a temperature measuring sensor at the center position thereof, and the temperature measuring sensors are provided on the lower surface side of the wafer mounting table, and are arranged in the radial direction of the wafer mounting surface. in any of the heating zones adjacent to, the wafer heater unit is the distance of those two center positions from the center of其's heating zone more than 50% of the maximum distance to the boundary of the heating zone.
  The plurality of heating zones include a central fan-shaped heating zone obtained by dividing the circular central part into three equal parts in the circumferential direction, a peripheral fan-shaped heating zone obtained by dividing the annular peripheral part into six equal parts in the circumferential direction, the circular central part, and the annular The heater unit for heating a wafer according to claim 1, comprising an intermediate fan-shaped heating zone obtained by dividing an annular intermediate portion between the peripheral portion and the peripheral portion into six equal parts in the circumferential direction.   The through holes for lift pins of the semiconductor wafer are provided between heating zones adjacent in the circumferential direction and / or between heating zones adjacent in the radial direction among the plurality of heating zones. The heater unit for heating a wafer according to claim 2.

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