JP2019071351A - Heater unit for wafer heating - Google Patents

Abstract

To provide a heater unit for wafer heating capable of improving thermal uniformity of a wafer mounting surface.SOLUTION: In a heater unit 10 having a discoid wafer mounting table 11 including a wafer mounting surface 11a, and multiple heating circuits 13a extending on a surface in parallel with the wafer mounting surface 11a and heating the wafer mounting surface 11a, multiple insertion holes 10a for a rod-like support part 21 for mounting and separating a semiconductor wafer W are bored in the wafer mounting table 11 in the thickness direction, multiple heating zones defined on the wafer mounting surface 11a by the multiple heating circuits 13a has a classification pattern where each of the multiple regions sectioned into concentric circle is further sectioned in the hoop direction, and of the multiple regions, the region where the multiple insertion holes 10a are arranged in the boundary in the radial direction has the number of division in the hoop direction equal to an integer times of the multiple insertion holes 10a.SELECTED DRAWING: Figure 2

Description

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

  In a semiconductor manufacturing apparatus for manufacturing semiconductor devices such as LSIs and memories, a series of film formation such as CVD or sputtering on a semiconductor wafer, coating of a resist, photolithography such as exposure and development, etching for patterning, etc. A thin film process consisting of steps is performed. In these thin film processes, since the process is generally performed with the semiconductor wafer heated to a predetermined temperature, for example, in a coater development apparatus in which photolithography is performed, the semiconductor wafer of the object to be processed is placed and heated from its lower surface. A wafer heating heater unit also referred to as a susceptor is used.

  For example, as disclosed in Patent Document 1, the above-mentioned heater unit for wafer heating supports a wafer mounting table made of a ceramic disk-shaped member having a flat wafer mounting surface on the upper surface, and this from the lower surface side. A heating circuit such as an electric heating coil or a patterned metal thin film is embedded in parallel to the wafer mounting surface in the interior of the wafer mounting table. A pair of electrode terminals provided on the lower surface side of the wafer mounting table is electrically connected to both ends of the heating circuit, and the heating circuit is connected from an external power supply through the pair of electrode terminals and the lead wire thereof. Power is supplied.

  In the above-described heater unit for wafer heating, it is required to uniformly heat the semiconductor wafer over the entire surface by enhancing the heat uniformity on the wafer mounting surface so that the quality of the semiconductor device as a product does not vary. ing. Therefore, in order to make the circuit pattern of the heat generating circuit dense and prevent temperature unevenness from occurring or individually perform temperature control for each of a plurality of heating zones (multi-zones) defined on the wafer mounting surface, In each of the plurality of heating zones, a heating circuit extending parallel to the wafer mounting surface is disposed to feed power separately.

Japanese Patent Application Laid-Open No. 2003-17224

  Although extending the plurality of heating circuits to a plane parallel to the wafer mounting surface as described above makes it possible to individually control the temperature of the plurality of heating zones defined on the wafer mounting surface, In a control system that controls the amount of heat generation of the heating circuit disposed in each heating zone with voltage or current, one temperature sensor is generally provided for each heating zone as a temperature detector. If a singular point such as a cool spot exists in the heating zone, it may be difficult to control the temperatures of the plurality of heating zones in a well-balanced manner, and temperature control may not be performed well.

  In the past, the adverse effect on the temperature uniformity of the wafer mounting surface caused by the above-mentioned problems with temperature control was negligible because it was negligible, but with the recent miniaturization of semiconductor devices, As for the temperature of the wafer mounting surface on which the semiconductor wafer is mounted, more precise control is required. Therefore, the above-mentioned problem which has not been regarded as a problem is emerging. The present invention has been made in view of such circumstances, and it is possible to improve the heat uniformity of the wafer mounting surface by controlling the temperature of the plurality of heating zones defined on the wafer mounting surface in a well-balanced manner. It is an object of the present invention to provide a wafer heating heater unit.

  In order to achieve the above object, a wafer heating heater unit according to the present invention comprises a disk-like wafer mounting table having a wafer mounting surface on which a semiconductor wafer is mounted, and a surface parallel to the wafer mounting surface. A wafer heating heater unit having a plurality of heating circuits extending upward to heat the wafer mounting table, wherein the wafer mounting table mounts the semiconductor wafer on the wafer mounting surface and A plurality of insertion holes for rod-like supporters to be separated are formed in the thickness direction, and a plurality of heating zones defined on the wafer mounting surface by the plurality of heating circuits are concentrically partitioned. Each of the plurality of regions further has a division pattern equally divided in the circumferential direction, and among the plurality of regions, those in which the plurality of insertion holes are arranged at the boundary portion in the radial direction are The number of divisions in the circumferential direction is before It is characterized by an integer multiple of the number of the plurality of insertion holes.

  According to the present invention, temperature control of the plurality of heating zones defined on the wafer mounting surface can be performed in a well-balanced manner, so that it is possible to improve the heat uniformity of the wafer mounting surface.

FIG. 7 is a longitudinal sectional view of a specific example of a wafer heating heater unit according to the present invention. It is a top view which shows the division pattern of several heating zones on the wafer mounting surface defined by several heating circuit which the heater unit for wafer heating of FIG. 1 has. 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 Comparative example 1 and 2 of this invention.

  First, embodiments of the present invention will be listed and described. The embodiment of the heater unit for heating a wafer according to the present invention comprises a disk-like wafer mounting table provided with a wafer mounting surface on which a semiconductor wafer is mounted, and a surface extending parallel to the wafer mounting surface. A wafer heating heater unit having a plurality of heating circuits for heating the wafer mounting table, wherein the wafer mounting table is a rod-like support for mounting and separating the semiconductor wafer with respect to the wafer mounting surface A plurality of insertion holes for a part are bored in the thickness direction, and a plurality of heating zones defined on the wafer mounting surface by the plurality of heating circuits are concentrically divided. Further, each of the plurality of areas has a division pattern equally divided in the circumferential direction, and among the plurality of areas, the plurality of insertion holes are disposed at the radial boundary portion, the number of divisions in the circumferential direction Is the number of the plurality of insertion holes It is characterized by an integer multiple. As a result, the temperature control of the plurality of heating zones defined on the wafer mounting surface can be performed in a well-balanced manner, so that it is possible to improve the heat uniformity of the wafer mounting surface.

  In the embodiment of the heater unit for heating a wafer according to the present invention, the plurality of concentric regions are composed of a circular central portion, an annular intermediate portion positioned on the outer peripheral side of the circular central portion, and an annular peripheral portion. The circular central portion is preferably equally divided into three in the circumferential direction, the annular intermediate portion is equally divided into six in the circumferential direction, and the annular peripheral portion is preferably equally divided into six in the circumferential direction. This makes it possible to further improve the heat uniformity of the mounting surface on which the semiconductor wafer is mounted. Further, in the embodiment of the heater unit for wafer heating of the present invention, the heating zones adjacent in the circumferential direction among the plurality of heating zones and / or between the heating zones adjacent in the radial direction, It is preferable that a plurality of insertion holes be provided at equal intervals in the circumferential direction. Thereby, the bad influence to the thermal uniformity of the mounting surface by the penetration 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, the wafer heating heater unit 10 according to one specific example of the present invention is a disk-shaped wafer mounting table 11 having a wafer mounting surface 11a on which the semiconductor wafer W is mounted. A support plate 12 is formed in a disk shape having an outer diameter substantially equal to that of the wafer mounting table 11 and supports the wafer mounting table 11 from the lower surface side over the entire surface, and the wafer mounting table 11 and the support plate 12 And a circular thin-film heat generating module 13 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 14 provided on the lower surface side of the support plate 12. The semiconductor wafer W placed on the wafer placement surface 11a is placed on the wafer placement surface 11a or lifted from the wafer placement surface 11a by the support mechanism 20 described later. Therefore, in the wafer heating heater unit 10, a plurality of insertion holes 10a for inserting a plurality of rod-like support portions (also referred to as lift pins) of the support mechanism 20 are formed in the thickness direction.

  The wafer mounting table 11 is preferably made of a material having a high thermal conductivity so as to achieve extremely high temperature uniformity, that is, high heat uniformity over the entire surface of the wafer mounting surface 11a. For example, copper, aluminum, etc. Metal is more preferred. The material of the wafer mounting table 11 may be a ceramic or ceramic complex having high rigidity (Young's modulus) such as silicon carbide, aluminum nitride, Si-SiC, Al-SiC, etc., whereby the flatness of the wafer mounting surface 11a is always obtained. It is possible to maintain the temperature, and 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 it is possible to reduce the heat capacity and to increase the temperature rising and lowering speed.

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

  It is preferable that the wafer mounting table 11 and the support plate 12 be 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 thermally expanded freely in the direction of the wafer mounting surface 11 a according to the respective temperatures. For example, a female screw (not shown) is provided on the lower surface side of the wafer mounting table 11 by inserting a male screw (not shown) from below into a screw hole (not shown) which penetrates through the support plate 12 in the thickness direction. Preferably, for example, a bearing (not shown) is interposed between the bearing surface of the male screw and the lower surface of the support plate 12 which is the contact portion. In this case, also in the heat generating module 13, the insertion holes of the female screw portion are provided at positions corresponding to the screw holes of the support plate 12.

  Here, the screwing portion is preferably disposed outside the effective diameter of the heating circuit described later. By doing this, it is possible to realize a mounting table with high temperature uniformity in which local cool spots hardly occur. When the screwing portion is disposed within the effective diameter of the heating circuit, the plurality of heating zones are disposed between the heating zones adjacent in the circumferential direction and / or between the heating zones adjacent in the radial direction. It is preferable that the division pattern be axisymmetric with respect to a radial line segment of the wafer mounting surface passing through the arrangement position, thereby suppressing the 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 division pattern is line symmetrical with respect to the line segment. As described above, when there are singular points such as mechanical parts and electrical parts that interfere with any or all of the mounting table, the heating unit, and the support plate, these singular points are disposed outside the effective diameter of the heating circuit. Alternatively, by arranging the heating zones between the adjacent heating zones within the effective diameter and at the position of the symmetry line of the sectional pattern, the desired function can be exhibited without compromising the temperature uniformity. The effective diameter of the heat generating circuit is the diameter of a circular area of the wafer mounting surface 11a where the heat generating circuit 13a described later is disposed immediately below.

  The heat generating module 13 held between the wafer mounting table 11 and the support plate 12 has a plurality of heat generating circuits 13 a extending on a surface parallel to the wafer mounting surface 11 a. The plurality of heating circuits 13a are covered with an insulator so as to be in an electrically insulated state from the wafer mounting table 11 and the support plate 12 described above. The conductive metal foil is patterned by etching or laser processing to form a plurality of heat generating circuits 13a, which can then be fabricated by sandwiching it from above and below with a heat resistant insulating sheet such as a polyimide sheet.

  Alternatively, when 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, the thickness of the conductive metal foil used for the heat generating circuit 13a is thin, etc. Heat-resistant insulation sheet such as conductive metal foil and polyimide sheet for electrical insulation in advance and thermo-compression bonding, and after this thermo-compression bonding, only conductive metal foil is patterned by etching etc. The heat generating module 13 is integrated by integrating the film and the pattern foil (that is, the heat generating circuit 13a in the form of a foil) and further laminating a polyimide film on the integrated heat generating circuit 13a in the form of a foil. May be produced.

  As described above, by providing the plurality of heating circuits 13a extending in parallel with the wafer mounting surface 11a in the heating module 13, the wafer mounting surface 11a can be divided into a plurality of heating zones. The division pattern of the plurality of heating zones defined by the plurality of heating circuits 13a is not particularly limited, but the disk-shaped wafer mounting table 11 generally dissipates heat from the peripheral portion having a larger surface area than the central portion. Because there are many, in the steady state, the peripheral portion is likely to be locally low in temperature. On the other hand, when the semiconductor wafer is mounted on the mounting table, the outer diameter of the mounting table is generally larger than the diameter of the wafer. Distribution occurs. Thereafter, the temperature of the mounting table is raised to a predetermined temperature by the operation of the control system. However, since the temperature distribution is affected, the transition temperature distribution of the semiconductor wafer also becomes concentric center cooling. In order to correct such a center-cool type temperature distribution, it is preferable that the division pattern of the heating zone be concentrically divided 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 use a division pattern in which the wafer mounting surface 11a is divided concentrically and further divided equally in the circumferential direction.

  That is, in the divided patterns 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 side of the annular intermediate portion B. It is divided concentrically into an annular peripheral portion C, and the circular central portion A is equally divided into three in the circumferential direction as central fan-shaped heating zones A1 to A3, and the annular intermediate portion B is an intermediate portion fan-shaped The heating zones B1 to B6 are equally divided into six in the circumferential direction, and the annular peripheral portion C is equally divided into six circumferentially equal areas as the heating zones C1 to C6.

  Furthermore, in the heater unit 10 according to one specific example of the present invention, of the concentric circular regions consisting of the circular central portion A, the annular middle portion B, and the annular peripheral portion C, which are divided concentrically, In the case where the plurality of insertion holes 10a are arranged at the boundary portion, the number of divisions in the circumferential direction is an integral multiple of the number of the plurality of insertion holes 10a. That is, in the divided pattern shown in FIG. 2, three lift pin insertion holes 10 a are provided at the boundary between the circular central portion A and the annular middle portion B adjacent to each other in the radial direction. Then, one circular central portion A is equally divided into three in the circumferential direction, so that the number of divisions in the circumferential direction is equal to the number of the insertion holes 10a (that is, 1 time). Further, the other annular intermediate portion B is equally divided into six in the circumferential direction, so that the number of divisions in the circumferential direction is twice the number of the insertion holes 10a.

  As described above, it is preferable that the plurality of insertion holes 10a be arranged at equal intervals in the circumferential direction at the boundary between the heating zones adjacent in the radial direction of the wafer mounting surface 11a. Furthermore, as shown in FIG. 2, it is preferable that the plurality of insertion holes 10a be arranged also at the boundary between the heating zones adjacent in the circumferential direction of the wafer mounting surface 11a. That is, in the division pattern shown in FIG. 2, in addition to the three insertion holes 10a being disposed at the boundary between the circular central portion A and the annular intermediate portion B, the central fan-shaped heating zones A1 and A2 and , A2 and A3, and A3 and A1. By providing the lift pin insertion holes between the heating zones adjacent in the radial direction and / or between the heating zones adjacent in the circumferential direction as described above, the adverse effect of the heat uniformity on the mounting surface 11 a due to the insertion holes Can be reduced.

  There is no particular limitation on the circuit pattern of the heating circuit (not shown) provided in each heating zone, and various circuit patterns can be provided. For example, it is possible to form a circuit pattern formed in a one-stroke writing shape with a plurality of concentrically 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 heating density of the plurality of heating circuits may be different for each heating zone. For example, as described above, since the outside diameter of the mounting table is generally larger than the diameter of the wafer, when the semiconductor wafer is mounted on the mounting table, the center of the mounting table is concentrically cooled at a center portion whose temperature is lower than that of the outer peripheral portion. A mold temperature distribution results. Thereafter, the temperature of the mounting table is raised to a predetermined temperature by the operation of the control system. However, since the temperature distribution is affected, the transition temperature distribution of the semiconductor wafer also becomes concentric center cooling. In order to correct such a center-cool type temperature distribution, by designing the heat density of the central fan-shaped heating zones A1 to A3 high, it is possible to further improve the transient temperature uniformity at the time of wafer placement. . The method of increasing the heat generation density can be realized by narrowing the pitch of the circuit pattern of the heat generating circuit or narrowing the width of the conductive wire constituting the heat generating circuit.

  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 separated space between the heating zones adjacent to each other from the above total area of the heat generating module 13) And the ratio of the effective heat generation area, i.e., the ratio of the effective heat generation area is preferably 80% or more.

  The wafer heating heater unit 10 according to one embodiment of the present invention is provided with a temperature measuring sensor (not shown) consisting of a temperature measuring element whose resistance value is adjusted, for example, in each of a plurality of heating zones at the center position of the heating zone. In addition, it is preferable to individually control the heating circuit in the heating zone based on the detection value of each temperature measurement sensor. Here, the central position of the heating zone can be defined as a geometrical central point in the case of a general shape such as a circle or a triangle, and in the case of a line symmetrical shape, a symmetrical line segment which is the axis of symmetry It can be defined as the middle point of For example, in the case of a fan-shaped heating zone as shown in FIG. 2, the center position is at the middle angular position in the circumferential direction and at the middle position in the radial direction.

  By configuring the control system as described above, the mounting surface 11a can be locally heated, so that, for example, the mounting surface 11a is partially cooled by opening and closing the load lock or the like. Even so, it becomes possible to maintain good thermal uniformity. The temperature measuring sensor described above is, for example, provided with a counterbore hole of a size that the temperature measuring sensor fits on the lower surface side of the wafer mounting table 11, and an adhesive is applied to the bottom surface to fix the temperature measuring sensor. The temperature can be detected well.

  Returning to FIG. 1 again, the semiconductor wafer W is mounted on the wafer mounting surface 11a below the wafer heating heater unit 10 according to one specific example of the present invention, or the semiconductor wafer W is mounted on the wafer mounting surface. A support mechanism 20 is provided which is spaced apart from 11a. The support mechanism 20 includes a plurality of rod-like support portions 21 which protrude and retract from the insertion holes 10 a provided in the wafer heating heater unit 10, and a drive portion 22 which reciprocates them in the vertical direction.

  Further, below the wafer heating heater unit 10 according to one embodiment of the present invention, a cooling unit 30 for rapidly cooling the heater unit 10 is provided. The cooling unit 30 is movable cooling that can reciprocate between an abutting position abutted against the lower surface side of the support plate 12 as indicated by an alternate long and short dash line and a separated position separating from the support plate 12 as indicated by a solid line. It has a plate 31 and a stationary 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, or an alloy or stainless steel mainly containing at least one of them. It is preferable to do.

  The stationary 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), air, or a general-purpose refrigerant such as water circulates. The form of the refrigerant flow path is not particularly limited. For example, a metal pipe such as Cu is placed along the lower surface side of the metal plate member as a refrigerant flow path, and stainless steel joints are provided at both ends of the metal pipe. While being attached, in a state where the metal pipe is pressed against the plate-like member by the pressing plate, the pressing plate and the plate-like member can be mechanically coupled with each other by a screw or the like.

  Alternatively, in order to obtain higher thermal efficiency, for example, a spiral counterbore groove is provided on the lower surface side of the metal plate-like member, and a metallic pipe for circulating refrigerant formed in a spiral shape is installed in the counterbore groove. Good. In this case, in order to maintain a 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 counterbore with a caulking material, a sealant, an adhesive or the like. Alternatively, prepare two plate-like members of substantially the same shape and made of the same material, and form a groove serving as a flow path by machining on one side or both sides of the two, so that the side of the flow side faces each other The sheet members may be stacked and integrated by a bonding method such as brazing.

  The movable cooling plate 31 is attached to an elevating mechanism 33 composed of an air cylinder or the like. As a result, by operating the elevating mechanism 33, it becomes possible to reciprocate the stationary cooling plate 31 between the contact position and the separated position described above. It should be noted that the cooling stage 32 having the refrigerant flow path itself may be reciprocated between a position contacting the lower surface side of the support plate 12 and a position separating from the lower surface side without using the movable cooling plate 31 .

  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. The intervening layer preferably has cushioning properties (flexibility) in the thickness direction, and preferably has heat resistance. Furthermore, it is preferable to have high thermal conductivity, for example, of 1 W / m · K or more. Examples of such a material include a foam metal, a metal mesh, a graphite sheet, or a resin sheet such as a fluorine resin, a polyimide resin, or a silicone resin. In addition, it becomes possible to make thermal resistance smaller by containing heat conductive fillers, such as carbon, in said resin sheet. The wafer heating heater unit 10 and the cooling unit 30 according to one embodiment of the present invention are preferably housed in a container 40 made of stainless steel.

  Although the wafer heating heater unit of the present invention has been described above with reference to one embodiment, the present invention is not limited to the embodiment, and various modifications can be made without departing from the scope of the present invention. It is possible. That is, the technical scope of the present invention is the scope of the claims and the equivalents thereof.

Example 1
The wafer heating heater unit 10 provided with the support mechanism 20 and the cooling unit 30 below as shown in FIG. 1 was manufactured, and the heat 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. Three insertion holes for lift pins were evenly drilled in the circumferential direction of the wafer mounting surface 11 a at a position of PCD 120 mm of this copper plate. In addition, 15 counterbore holes are formed at the center position described later of the surface opposite to the surface to be the wafer mounting surface 11a of this copper plate, and each of these counterbore holes is made of ceramics (W2 mm × D2 mm × H1 mm) The temperature measuring element of the above was adhesively fixed using a silicone adhesive.

  Next, a disk-shaped Si-SiC plate with a diameter of 320 mm and a thickness of 3 mm was prepared as the support plate 12. Also in this Si-SiC plate, three insertion holes for lift pins were equally drilled in the circumferential direction of the wafer mounting surface 11a at a position of PCD 120 mm. Furthermore, the through-hole for penetration of the lead wire of the said temperature-measurement element, the screw mentioned later, etc. was provided in this Si-SiC board. Next, a circuit pattern of the plurality of heating circuits 13a is formed by etching on a stainless steel foil having a thickness of 20 μm as a resistance heating element to be the plurality of heating circuits 13a of the heating module 13. Then, the resistance heating element was covered from both upper and lower sides with a 50 μm thick polyimide sheet and thermocompression bonded to prepare a circular film-like heat generating module 13 having a diameter of 320 mm.

  Here, the plurality of heating zones in which the plurality of heating circuits 13a of the above-described heating module 13 are provided are made to have the division pattern of FIG. Specifically, three concentric circles of φ 120 mm, φ 246 mm, and φ 302 mm are divided into three parts, ie, circular central portion A, annular intermediate portion B, and annular peripheral portion C with respect to the center point of circular heat generating module 13, and further φ 120 mm. The central portion A of the circle is equally divided into three in the circumferential direction to form central fan-shaped heating zones A1 to A3, and the annular intermediate portion B having an outer diameter of 246 mm and an inner diameter of 120 mm is circumferentially divided into six equal portions. An annular peripheral portion C having an outer diameter of 302 mm and an inner diameter of 246 mm is equally divided into six in the circumferential direction to form peripheral fan-shaped heating zones C1 to C6. Further, in the heat generating module 13, three insertion holes for lift pins were equally drilled in the circumferential direction of the wafer mounting surface 11a at a position of PCD 120 mm. The above-mentioned temperature measurement element was arranged at the center position of each section so that the 15 heating circuits 13a provided in each of the heating zones of these 15 sections in total were individually controlled. The feed cable of the heating circuit is also drawn out for each section.

  The heat generating module 13 manufactured in this manner is sandwiched between the wafer mounting table 11 and the support plate 12, and a screw is inserted into a through hole previously provided in the support plate 12 and screwed onto the wafer mounting table 11. did. Thus, a wafer heating heater unit 10 was produced, 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. As the above-mentioned screw, a fastening screw having a bearing on the bearing surface was used so that the wafer mounting table 11 and the support plate 12 would not be deformed due to the thermal expansion difference. Three fastening screws were provided for PCD 120 mm, and six fastening screws were provided for PCD 310 mm. Also, in order to suppress heat escape from the lead wires of the temperature measuring element, the lead wires of the temperature measuring element taken out from the support plate 12 are adhered and fixed with silicone resin in a state of being in contact with the support plate 12 over a length of 30 mm. did.

  Next, below the heater unit 10 for wafer heating, a support mechanism 20 for mounting the semiconductor wafer W on the wafer mounting surface 11 a or separating it from the wafer mounting surface 11 a is provided. The support mechanism 20 includes three rod-like support portions 21 which protrude and retract from the insertion holes 10a provided in the wafer heating heater unit 10, and a drive portion 22 which reciprocates them in the vertical direction. Further, as the cooling unit 30, a disk-shaped aluminum alloy plate of 320 mm in diameter × 12 mm in thickness for the movable cooling plate 31, and a disk-shaped aluminum alloy plate of 320 mm in diameter × 12 mm in thickness for the stationary cooling stage 32. Prepared. A flexible silicone sheet is disposed on the aluminum alloy plate for the movable cooling plate 31 so that the entire surface of the supporting plate 12 and the movable cooling plate 31 is in contact with the upper surface side in contact with the support plate 12. . On the other hand, on the lower surface of the aluminum alloy plate for stationary cooling stage 32, a phosphorus-deoxidized copper pipe having an outer diameter of 6 mm and a thickness of 1 mm for refrigerant channel 32a was attached using a screw. Then, joints for supplying and discharging the refrigerant were attached to both ends of the copper pipe.

  The supporting portion 21, the feeding cable, the lead wire of the temperature measuring element, and the leg portion 14 erected from the bottom of the container 40 described later are inserted into both aluminum alloy plates as the cooling unit 30 manufactured in this manner. A through hole was provided. Further, the aluminum alloy plate for the stationary cooling stage 32 was provided with a through hole through which the rod of the elevating mechanism 33 consisting of the air cylinder of the movable cooling plate 31 is inserted. The above-mentioned cooling unit 30 was placed in a stainless steel container 40 having a side wall of 1.5 mm thick and opened at the top. The elevating mechanism 33 was attached to the lower side of the fixed cooling stage 32, and the rod was inserted through the above-mentioned through hole for rod insertion, and the movable cooling plate 31 was attached to the tip thereof. Thus, the wafer heating heater unit 10 of the sample 1 provided with the support mechanism 20 and the cooling unit 30 was manufactured. 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 division pattern of the heat generating module held between the wafer mounting table 11 and the support plate 12 is changed to the division patterns of FIGS. 3 (a) and 3 (b) instead of FIG. The heater units for wafer heating of Samples 2 and 3 equipped with a cooling unit were manufactured. That is, in the heat generating module of the heater unit for wafer heating of sample 2, three concentric circles of φ 95 mm, φ 246 mm and φ 302 mm with respect to the center point of circular central portion D, annular intermediate portion E, and annular peripheral portion F Divide the circular central part D and the annular middle part E into circular heating zones and annular heating zones as they are without dividing them in the circumferential direction. Only the annular peripheral part F with an outer diameter of φ 302 mm and an inner diameter of φ 246 mm in the circumferential direction As a result, the peripheral fan-shaped heating zones F1 to F4 are obtained. A temperature measuring element was provided at the center position of each of the six heating zones in total. However, for the annular intermediate portion E, a temperature measuring element was provided at one position on the circumference of φ 151 mm with respect to the center point of the heat generating module.

  On the other hand, in the heat generating module of the wafer heating heater unit of sample 3, the four concentric circles φ 95 mm, φ 171.5 mm, φ 246 mm and φ 302 mm with respect to the center point form a circular central portion G, an inner annular intermediate portion H, and an outer side. The inner intermediate portion H is divided into four into an annular intermediate portion I and an annular peripheral portion J, and an inner annular intermediate portion H having an outer diameter of 171.5 mm and an inner diameter of 95 mm is equally divided into two in the circumferential direction to form inner intermediate fan heating zones H1 to H2. The outer annular intermediate portion I having an outer diameter of 246 mm and an inner diameter of 171.5 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 of 302 mm and an inner diameter of 246 mm in the circumferential direction. Equal parts were divided into peripheral fan-shaped heating zones J1 to J8. A temperature measuring element was provided at the center position of each of these 15 zones of heating zones.

  With respect to the heater units of Samples 1 to 3 prepared above, first, the flatness of the wafer mounting surface 11 a was measured by a commercially available three-dimensional measuring device. Next, power was supplied to the plurality of heating circuits 13a for each of the heater units of Samples 1 to 3 to raise the temperature from normal temperature to 110 ° C., and then held for 1 hour while controlling temperature at 110 ° C. Thereafter, a commercially available wafer thermometer in which a temperature measuring sensor is embedded was installed on the wafer mounting surface 11a, and the soaking range, which is the difference between the maximum temperature and the minimum temperature in the wafer mounting surface 11a, was measured. The results are shown in Table 1 below.

  From the results in Table 1 above, the soaking range was 0.17 ° C. in the heater unit of Sample 2. According to the detailed temperature distribution, the maximum temperature and the minimum temperature exist in the annular intermediate portion E, and the vicinity of the bolt fastening the wafer mounting table 11 and the support plate 12 and the insertion hole for the support portion 21 The area around 10a was a low temperature area (cool spot). This is because the annular intermediate portion E is constituted by only one heating zone, and therefore, the influence is caused by the fact that the heat generating circuit can not be disposed in the fastening bolt or the insertion hole 10a disposed in the one heating zone. And, it is considered that the temperature sensor can not detect the heat radiation from the part of the fastening bolt and the insertion hole 10a.

  In the heater unit of sample 3, the soaking range is 0.21 ° C., and according to the detailed temperature distribution, in the inner annular intermediate portion H divided into two equal parts, like the heater unit of sample 2, the fastening bolt, support portion 21 The low temperature region (cool spot) was around the insertion hole 10a for the purpose. The reason is also considered to be the same as the heater unit of sample 2 described above, and the number of heating zones divided in the circumferential direction is not an integral multiple of the number of fastening bolts and insertion holes 10a. It is considered that the thermal uniformity was adversely affected.

  On the other hand, in the heater unit of sample 1, since the positions of the fastening bolts on the inner peripheral side and the insertion holes 10a for the support portion 21 are arranged at the boundary between the circular central portion A and the annular intermediate portion B adjacent to each other in the radial direction The effects of heat radiation and the like are dispersed, and the number of divisions in the circumferential direction of the circular central portion A and the annular intermediate portion B becomes an integral multiple of the number of fastening bolts and the number of insertion holes 10a for the support portion 21. As described above, the number of fastening bolts is three, the number of insertion holes 10a for the support portion 21 is three, and the fastening bolts and the insertion holes 10a are at the boundary between adjacent heating zones in the circumferential direction. Because of the arrangement, both of the heating zones adjacent to each other in the radial direction and the heating zones adjacent to each other in the circumferential direction, that is, a total of four heating zones distribute the adverse effects of the fastening bolts and the insertion holes 10a. Singularity as was not confirmed.

Example 2
The heater units of Samples 4 to 6 are manufactured in the same manner as Samples 1 to 3 in Example 1 except that the material of wafer mounting table 11 is changed to copper and Si-SiC is used, and the same as Example 1 The evaluation of The results are shown in Table 2 below together with the flatness of the wafer mounting table 11.

  It can be seen from Table 2 that the same tendency as in Example 1 is present. In addition, as compared with Example 1, the heater units of Samples 4 to 6 all showed a slight improvement in thermal uniformity. This is because the flatness of the wafer mounting table 11 is stabilized by replacing the material of the wafer mounting table 11 with Si-SiC with high rigidity, whereby the distance between the wafer mounting surface 11 a and the wafer is uniform over the entire surface. It is guessed that it is because it became.

DESCRIPTION OF SYMBOLS 10 wafer heating heater unit 10 a lift pin insertion hole 11 wafer mounting table 11 a wafer mounting surface 12 support plate 13 heat generation module 13 a heat generation circuit 14 leg portion 20 support mechanism 21 support portion 22 drive portion 30 cooling unit 31 movable cooling plate 32 Fixed type cooling stage 32a Refrigerant flow path 33 Lifting 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 fanned heating zone C annular peripheral part C1 to C6 peripheral part fan shaped heating zone D Circular central portion E annular intermediate portion F annular peripheral portion F1 to F4 peripheral portion fan-shaped heating zone G circular central portion H inner annular intermediate portion H1 to H2 inner intermediate portion fan-shaped heating zone I outer annular intermediate portion I1 to I4 outer intermediate portion fan-shaped heating Zone J Annular edge J1 to J8 Peripheral fan heating zone W Semiconductor wafer

Claims (3)

A disk-like wafer mounting table having a wafer mounting surface on which a semiconductor wafer is mounted, and a plurality of heating circuits which extend on a surface parallel to the wafer mounting surface to heat the wafer mounting table A heater unit for heating a wafer,
In the wafer mounting table, a plurality of insertion holes for rod-like support portions for mounting and separating the semiconductor wafer with respect to the wafer mounting surface are bored in a thickness direction, and the plurality of heating circuits The plurality of heating zones defined on the wafer mounting surface has a division pattern in which each of the plurality of concentrically divided regions is further divided equally in the circumferential direction, and the plurality of heating zones The wafer heating heater unit wherein the plurality of insertion holes are arranged at the boundary in the radial direction among the plurality of insertion holes in the circumferential direction is an integral multiple of the number of the plurality of insertion holes.   The plurality of concentric regions are composed of a circular central portion, an annular intermediate portion positioned on the outer peripheral side of the circular central portion, and an annular peripheral portion, and the circular central portion is equally divided into three in the circumferential direction. The wafer heating heater unit according to claim 1, wherein the annular intermediate portion is equally divided into six in the circumferential direction, and the annular peripheral portion is equally divided into six in the circumferential direction.   Among the plurality of heating zones, the plurality of insertion holes are provided at equal intervals in the circumferential direction between the heating zones adjacent in the circumferential direction and / or between the heating zones adjacent in the radial direction. The heater unit for wafer heating according to claim 1 or claim 2.

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