JP5694824B2 - Heating device - Google Patents

Description

  The present invention relates to a heating apparatus, for example, a heating apparatus that heats a semiconductor wafer to a predetermined temperature.

  2. Description of the Related Art Conventionally, in a coater / developer apparatus used for a pattern printing process or the like on a semiconductor wafer, the wafer is heated to a predetermined temperature by a heating device. At this time, the wafer is placed on a substrate having a heat generating portion through a gap, and is heated by heat from the heat generating portion radiated through the substrate (see, for example, Patent Document 1).

  In the heating device of Patent Document 1, an aluminum substrate is used as a substrate, and a face plate is configured by including the aluminum substrate and a film heater attached to the lower surface of the aluminum substrate. In such an aluminum substrate of the face plate, a film heater is affixed to the lower surface, and an alumite layer is formed except for the part where the film heater is affixed, and the entire aluminum substrate has insulation and corrosion resistance. Has been granted.

JP 2008-277382 A

  By the way, since the front and back of the aluminum substrate are covered with an insulating film heater or an alumite layer, the entire face plate acts as a capacitor and is charged. Since the charged electric charge may be inadvertently discharged or leaked, the aluminum substrate of the face plate is grounded via a grounding member to a conductive base plate arranged to face downward.

However, if the aluminum substrate of the base plate and the face plate are simply connected by the ground member, the aluminum substrate bends upward or downward by the force from the ground member, and the gap between the face plate and the wafer on the face plate is constant. This causes a problem that the temperature distribution of the wafer is not uniform.
In addition, when the aluminum substrate is heated by the heating unit, heat escapes from the aluminum substrate side to the base plate side via the ground member, but depending on the connection position of the ground member to the face plate, the temperature of the face plate may be affected by the heat escape. The distribution is uneven, and as a result, the temperature distribution of the wafer placed on the face plate with a desired gap is also uneven, which affects the processing of the wafer.

  In particular, the time to raise or lower the substrate temperature by heating the aluminum substrate or cooling the aluminum substrate that has been heated to high is downtime, and in order to reduce such downtime, the heat capacity of the aluminum substrate is reduced. If the aluminum substrate is made thinner and the heat capacity is made smaller, the rigidity of the aluminum substrate is lowered, so that even a slight external force from the ground member is easily bent, and temperature distribution unevenness is likely to occur.

  An object of the present invention is to provide a heating device that can make the substrate less likely to be bent and reduce the influence of heat escape while reliably grounding, even when the substrate is remarkably thinned and the temperature change is accelerated. It is in.

  A heating device according to a first aspect of the present invention is a conductive base plate, a face plate that is positioned above the base plate and on which a wafer is placed, and is disposed between the base plate and the face plate to conduct each other. A ground member, and the face plate includes an aluminum substrate whose surface is electrically insulated except for a conductive portion with the ground member, and a heating unit that is provided on the aluminum substrate and heats the wafer. The conductive portion of the aluminum substrate with the ground member is provided in the center of the aluminum substrate, and a plurality of bent portions are provided in the middle of the ground member in the longitudinal direction. And

  In the heating device according to the second aspect of the invention, a conductive washer is interposed between the conductive portion of the aluminum substrate and the end of the ground member, and the thickness of the washer is around the conductive portion. The thickness of the insulating layer is equal to or greater than the thickness of the insulating layer.

  In the heating device according to the third aspect of the present invention, a holding bolt having a guide hole penetrating along the axial direction is screwed into the center of the base plate, and a lower end side is inserted into the guide hole at the center of the face plate. A long screw which is a lot portion to be inserted and whose upper end is a male screw portion which is screwed into a nut provided on the head of the holding bolt is inserted.

  In the heating device according to a fourth aspect of the present invention, the head portion of the holding bolt is provided with a holding portion to which the nut is slidably fitted up and down in a non-rotating state.

  In the heating device according to the fifth aspect of the present invention, a base plate, a face plate positioned above the base plate and on which a wafer is placed, and a coolant provided between the base plate and the face plate to cool the face plate Provided between a cooling pipe through which gas flows and the base plate and the face plate, guides the refrigerant gas ejected through the cooling pipe, and shields radiant heat from the face plate to the base plate. A thermal rectifying plate, wafer support means protruding from the upper surface of the face plate, a terminal block attached to the base plate and connected to wiring from an external power source, and between the base plate and the face plate Standing up A plurality of struts for supporting the face plate; a plurality of tension members for pulling the face plate toward the base plate; and a grounding member disposed between the base plate and the face plate to conduct each other. An aluminum substrate whose surface is electrically insulated except for a conductive portion with the ground member, and a heating terminal provided on the aluminum substrate for heating the wafer and connected to the terminal block. And a conductive portion of the aluminum substrate connected to the ground member is provided at the center of the aluminum substrate, and a plurality of bent portions are provided in the middle of the ground member in the longitudinal direction. It is provided.

  According to the first and fifth inventions, since a plurality of bent portions are provided in the middle of the longitudinal direction of the earth member, the bent members are bent so that the earth member faces the aluminum substrate upward. It can absorb the force to push up and pull down, and even when a thin aluminum substrate is used, it can prevent the aluminum substrate from bending up and down, and the gap between the aluminum substrate and the wafer is constant. Can be made uniform. In addition, since the end of the grounding member on the side of the aluminum substrate is connected to the center of the aluminum substrate, the influence of the temperature distribution due to the heat escape extends almost evenly around the center of the aluminum substrate. The uneven distribution can be eliminated, and the influence of heat escape on wafer processing can be reduced.

  According to the second invention, by providing the washer, the step between the base portion of the aluminum substrate and the insulating layer portion can be filled, and the end of the ground member is reliably conducted to the aluminum substrate via the washer. Can do.

  According to the third invention, the long screw is inserted from above the face plate and screwed into the nut disposed between the face plate and the base plate. At this time, the rod portion of the long screw is guided to the holding bolt. If the long screw is passed through the face plate, the rod part of the long screw may be inserted into the nut and guided into the guide hole. Even if the nut does not shift and move before screwing and the nut is not visible on the face plate, the long screw can be securely screwed into the nut, and assemblability can be improved.

  According to the fourth invention, since the nut is held in the non-rotating state by the holding portion, it is not necessary to hold the nut while the long screw is screwed in, and the assemblability can be further improved.

The disassembled perspective view which shows schematic structure of the heating apparatus which concerns on one Embodiment of this invention. Sectional drawing which shows the faceplate which comprises a heating apparatus. Sectional drawing which shows the support structure of the faceplate in the outer peripheral side of a baseplate. Sectional drawing which shows the support structure to the baseplate of the wafer mounting area | region of a faceplate. Sectional drawing which shows the holding structure of a gap ball. Sectional drawing which shows the earthing | grounding structure by an earth member. The perspective view which shows a ground member. The disassembled perspective view which shows a terminal block and a terminal. The figure which shows the modification of this invention. The figure which shows another modification of this invention.

[Description of the entire device]
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In FIG. 1, a heating apparatus 1 is an apparatus mounted on a coater / developer apparatus used in a semiconductor manufacturing process, and a semiconductor wafer (hereinafter simply referred to as a wafer) W such as a silicon wafer indicated by a two-dot chain line is patterned. It is comprised so that it may heat to the predetermined temperature according to various processes, such as a baking process.

  Specifically, the heating device 1 includes a disk-shaped base plate 2, a disk-shaped face plate 3 supported above the base plate 2, a cooling pipe 11 accommodated between the plates 2 and 3, and a heat shield. A wafer W provided with a rectifying plate 12 and mounted on the upper surface side of the face plate 3 with a predetermined gap C (FIG. 4) is heated by a film heater 32 (FIG. 2), which will be described later, constituting the face plate 3. It has come to be.

  The face plate 3 is provided with three insertion holes 30 for raising and lowering pins (not shown) for raising and lowering the wafer W. With the lifting pins raised from the insertion holes 30, the wafer W is loaded into the heating device 1 held at a predetermined temperature by the hand robot and placed on the upper ends of the lifting pins. Further, after the hand robot is retracted, the lifting pins are lowered, and the wafer W that has been lowered is placed on the face plate 3 via the gap balls 6.

While the wafer W is being processed, the wafer W is heated by the heating device 1 and maintained at a predetermined temperature. After the predetermined processing is performed on the wafer W, the lifting pins are raised again, and the wafer W that has risen along with the lifting pins is unloaded from the heating device 1 by the hand robot and replaced with the next wafer W.
Further, when the processing conditions (recipe) to be applied to the wafer W are changed and the temperature of the face plate 3 is changed from, for example, a high temperature to a low temperature, the refrigerant gas is supplied to the cooling pipe 11, and the small ejection holes ( The face plate 3 is cooled by the refrigerant gas ejected from (not shown). Thereafter, the refrigerant gas is guided to the cutoff rectifying plate 12 and exhausted from the center of the base plate 2. When the face plate 3 falls below the set temperature, the supply of the refrigerant gas is stopped, and the face plate 3 is again heated and held at the set temperature according to the processing conditions.

[Description of base plate]
The base plate 2 is made of metal, and stainless steel is used in this embodiment. Such a base plate 2 is provided with a plurality of openings 21 for weight reduction and an exhaust opening 22 for discharging the refrigerant gas used for cooling the face plate 3 from the center. Since the base plate 2 has a sufficient thickness, the rigidity of the entire heating device 1 is guaranteed. Further, eight terminal blocks 9 are provided at equal intervals on the lower surface on the outer peripheral side of the base plate 2 and are supplied with power from the outside (four are shown by broken lines in FIG. 1).

  Such a terminal block 9 is connected to a terminal 33 extending from the film heater 32 in a channel (C shape) and a wiring 24 (FIG. 8) from an external power supply (not shown). Power is supplied to the film heater 32 by conducting the currents through the circuit 9. Specific structures of the terminal block 9 and the terminal 33 will be described later.

[Description of face plate]
As shown in FIG. 2A, the face plate 3 has a structure in which film heaters 32 (32A, 32B) are attached to the upper and lower surfaces of an aluminum substrate 31 by hot pressing. As shown in FIG. 1, such a face plate 3 has eight wafer guides 4 arranged at equal circumferential intervals on the outermost peripheral side, and a plurality of columns 5 arranged at appropriate positions inside the wafer guides 4. It is supported by the base plate 2. A specific support structure by the wafer guide 4 and the support column 5 will also be described later.

  The aluminum substrate 31 has a thin plate shape and has a plate thickness of 1.5 mm in this embodiment. An alumite layer 34 is formed on the entire surface of the aluminum substrate 31 by alumite treatment. Such alumite treatment is applied to the outer peripheral end face and the inside of various through holes in addition to the upper and lower surfaces of the aluminum substrate 31.

  The film heater 32 has a configuration in which a circuit pattern for heat generation is formed by a stainless foil 36 on the surface of the base film 35 and this circuit pattern is covered with a cover film 37. As the films 35 and 37, polyimide resin is used. The film heater 32A attached to the lower surface of the aluminum substrate 31 so as to face the base plate 2 is supplied with power by providing the terminal 33 (FIG. 1). However, the upper surface of the aluminum substrate 31 faces the wafer W. The film heater 32B attached to is not provided with a terminal for power supply, and is not supplied with power.

That is, the film heater 32B on the upper surface is a dummy member having a circuit pattern substantially the same as the film heater 32A. By attaching film heaters 32A and 32B having substantially the same structure on both the upper and lower surfaces of the aluminum substrate 31, the linear expansion coefficients on both sides of the aluminum substrate 31 can be made the same, and bending due to thermal expansion during heating can be suppressed. As a result, the face plate 3 mainly expands in the in-plane direction (same as the radial direction) from the center toward the outside. The circuit pattern of the film heater 32B is arbitrary as long as there is no difference in the linear expansion coefficient from the film heater 32A, and is not limited to the circuit pattern substantially the same as the film heater 32A.
Further, as shown in FIG. 2B, an alumite layer 34 ′ having a thickness enough to eliminate the difference in linear expansion coefficient may be formed on the upper surface of the aluminum substrate 31 instead of providing the dummy film heater 32 B. Good. In this case, the alumite layer may not be provided on the lower surface of the aluminum substrate 31.

  Although not shown, the circuit pattern of the film heater 32 as the heating means is a small pattern in which the heat generating surface of the film heater 32 is arbitrarily divided into a central circular portion and an outer circular portion. A circuit is formed so that it is divided into regions and power is supplied to each small region independently. By dividing the heat generating surface into a plurality of small regions and independently generating heat, the temperature distribution of the heated wafer W can be made more uniform and uneven heating can be reduced.

  In the present embodiment in which a plurality of circuit patterns corresponding to each small region are formed, eight terminal blocks 9 are provided, and power supply terminals 33 are also provided at 16 locations as eight pairs. A terminal 33 that does not feed power to a plurality of regions among the 16 locations is a dummy, and is not electrically connected to the circuit pattern for heat generation.

  In order to uniformly heat the wafer W, it is desirable to divide the heat generating surface of the film heater 32 into a plurality of small regions, and the number of terminals 33 corresponding to the region to which power is supplied is sufficient. On the other hand, when the influence of the stress on the thin plate-like aluminum substrate 31 due to the reaction force (elastic force) of the terminals 33 is taken into consideration, it is preferable that each pair of terminals 33 is arranged at equal intervals along the circumferential direction. However, since it is not common for manufacturing reasons to arrange the number of terminals 33 corresponding to the region to be fed at equal circumferential intervals, eight pairs of terminals 33 including dummy are provided and arranged at equal circumferential intervals. doing.

  In the above face plate 3, the film heater 32 </ b> A generates heat by feeding power to the stainless steel foil 36 of the lower film heater 32 </ b> A, and the aluminum substrate 31 is heated. When the aluminum substrate 31 is heated, the wafer W placed on the face plate 3 is heated via the gas present immediately above the entire face plate 3. The temperature control at this time is performed by adjusting the power supply to the film heater 32A based on a signal from a temperature sensor (not shown) embedded in the aluminum substrate 31.

  Further, since the face plate 3 has a structure in which the conductive aluminum substrate 31 is sandwiched between insulating polyimide resins, the entire face plate 3 acts as a capacitor and is charged. Furthermore, when a pinhole exists in the base film 35, the electric charge charged in the aluminum substrate 31 may easily leak. For this reason, in the present embodiment, a part of the ground surface of the aluminum substrate 31 is exposed at the center of the lower surface of the face plate 3, and this exposed part is connected to the base plate 2 via the ground member 8 (FIGS. 6 and 7). Shorted and grounded. Details of the grounding structure by the ground member 8 will also be described later.

[Description of cooling pipe]
In addition, an annular cooling pipe 11 and a heat shield rectifying plate 12 are disposed between the base plate 2 and the face plate 3. A supply pipe 13 is connected to the cooling pipe 11 through a central exhaust opening 22, and refrigerant gas is supplied from the supply pipe 13 into the cooling pipe 11. The refrigerant gas is ejected from a plurality of ejection holes (not shown) provided in the cooling pipe 11 toward the center to cool the face plate 3 from the lower side.

  The face plate 3 uses a thin plate-like aluminum substrate 31 with a small plate thickness, so that the heat capacity is kept small. Therefore, the heating and cooling temperature can be changed quickly by turning on and off the power supply to the film heater 32A. However, it is possible to change the temperature more quickly by effectively cooling the face plate 3 with the refrigerant gas ejected from the cooling pipe 11.

[Description of heat shield rectifying plate]
The heat shield rectifying plate 12 prevents the refrigerant gas ejected from the cooling pipe 11 from flowing out from the opening 21 provided in the base plate 2, guides it to the central exhaust opening 22, promotes exhaust, and generates heat. The radiant heat from the face plate 3 to the base plate 2 is blocked. Thereby, the thermal expansion of the base plate 2 and the thermal influence on the various components attached to the base plate 2 can be suppressed.

[Description of support structure of face plate by wafer guide]
Hereinafter, a support structure by the wafer guide 4 on the outer peripheral side of the face plate 3 will be described with reference to FIGS. 1 and 3.
First, at the eight locations on the outer peripheral side of the base plate 2, first through holes 2 </ b> A penetrating up and down subjected to anodizing are provided. On the other hand, the wafer guide 4 has a support bolt 41 inserted from above into the first through hole 2A, and a resin guide member 42 disposed on the upper surface of the face plate 3 and in contact with the outer peripheral edge of the wafer W. And.

  The support bolt 41 includes a male screw portion 43 that passes through the first through hole 2A of the base plate 2 and a placement portion 44 that is integrally provided on the top of the male screw portion 43 and on which the face plate 3 is placed. Yes. Such a support bolt 41 passes the flat washer 45 and the spring washer 45 'through the male screw portion 43 protruding from the lower surface of the first through hole 2A in a state where the mounting portion 44 is placed on the upper surface of the base plate 2. It is fixed to the base plate 2 by screwing with the nut 46.

  The upper surface of the mounting portion 44 of the support bolt 41 is flat, and a first support ball 47 made of an extremely small ceramic is press-fitted into a part of the upper surface. A part of the first support ball 47 protrudes from the upper surface of the mounting portion 44 by a predetermined dimension. That is, in detail, the face plate 3 placed on the placement unit 44 is placed on the first support ball 47 in a point contact state. Since the contact area with the face plate 3 can be reduced by such point contact, heat transfer from the face plate 3 can be suppressed, and thermal expansion and contraction in the radial direction of the face plate 3 can be prevented. And since the 1st support ball 47 is a product made from a ceramic, heat conduction is lower than the aluminum used for the faceplate 3, the heat transfer from the faceplate 3 can be suppressed also in this point, and also in a clean environment It corresponds.

  In a state where the face plate 3 is placed on the placement portion 44, a metal ring member 48 is dropped into the first mounting hole 3A where the face plate 3 is anodized. It is placed on the upper surface of the part 44. The guide member 42 is fixed to the mounting portion 44 by a countersunk screw 49 that passes through the ring member 48 and is screwed into the female screw portion 44 </ b> A of the mounting portion 44.

  In such a structure, the face plate 3 is sandwiched and fixed between the lower surface of the guide member 42 and the first support ball 47. In the process in which the face plate 3 is clamped by tightening the countersunk screw 49, the lower surface of the guide member 42 contacts the ring member 48, so that excessive tightening of the countersunk screw 49 can be prevented. If the countersunk screw 49 is tightened too much, the face plate 3 is deformed so that it undulates at that point, and the wafer W cannot be placed at an appropriate position. The first mounting hole 3A of the face plate 3 is formed as a long hole having a predetermined length along the radial direction of the face plate 3, and allows thermal expansion and expansion / contraction of the face plate 3 in the radial direction. Further, the guide member 42 may be fixed by any fixing means in a state of being biased toward the base plate 2 on the face plate 3, and is not limited to screwing.

[Explanation of support structure of face plate with support]
Next, with reference to FIG. 1 and FIG. 4, the support structure by the support | pillar 5 of the face plate 3 is demonstrated.
The face plate 3 is supported by the base plate 2 via a plurality of support columns 5. As the support pillars 5, eight support pillars 5 </ b> A arranged at equal intervals on the outside of the wafer W indicated by a two-dot chain line, and arranged at equal intervals in the mounting area of the wafer W inside thereof. Eight struts 5B and three struts 5C arranged at equal intervals on the inner side are provided.

  A second through hole 2 </ b> B penetrating vertically is provided at a position corresponding to the column 5 of the base plate 2. The support column 5 is a bolt inserted from above into the second through hole 2B. The support column 5 has a male screw portion 51 that penetrates the second through hole 2B, and a placement portion 52 that is integrally provided on the top of the male screw portion 51 and on which the face plate 3 is placed. In a state where the portion 52 is placed on the upper surface of the base plate 2, the flat washer 53 and the spring washer 53 ′ are passed through the male screw portion 51 protruding from the lower surface of the second through-hole 2 </ b> B, and screwed with the nut 54, whereby the base plate 2 It is fixed to.

  The upper surface of the mounting portion 52 is also flat, and a ceramic second support ball 55 larger than the first support ball 47 is press-fitted into the center of the upper surface. A part of the second support ball 55 protrudes from the upper surface of the mounting portion 52 by a predetermined dimension. That is, the face plate 3 placed on the placement unit 44 is placed in a state of point contact with the second support ball 55 as in the support structure by the wafer guide 4. The effect of such point contact is the same as that of the support structure by the wafer guide 4.

  Further, since the face plate 3 is supported not only by the wafer guide 4 on the outer peripheral side but also at a plurality of locations in the wafer W mounting region from below by the pillars 5B and 5C, the thin plate-like aluminum having a small rigidity is provided. Although it is the face plate 3 using the substrate 31, it is possible to prevent bending by its own weight that is convex downward, and the wafer W can be reliably placed at an appropriate position.

  Here, in the vicinity of the place where the face plate 3 is supported by the support 5, there are provided second mounting holes 3 </ b> B penetrating the upper and lower film heaters 32 </ b> A and 32 </ b> B and the aluminum substrate 31. In the present embodiment, the second mounting hole 3B also penetrates the film heater 32A on the lower surface side, but there is no problem even if it does not penetrate the film heater 32A. In the second mounting hole 3B, a ceramic gap ball 6 as a wafer support means is press-fitted and held from above.

  The gap ball 6 protrudes from the upper surface of the face plate 3 by a predetermined amount. This protrusion amount corresponds to the gap C in FIG. That is, the wafer W is supported in a point contact state on these gap balls 6, and is placed at an appropriate position with a uniform gap C of a predetermined dimension from the upper surface of the face plate 3. However, in FIG. 4, the gap ball 6, the hole diameter of the second mounting hole 3 </ b> B, and the size of the gap C are greatly exaggerated in view of the thickness of the face plate 3 in consideration of easy viewing. Yes.

  In addition, the gap ball 6 is not provided in the vicinity of all the support portions by the support columns 5, and at the support locations supported by the support columns 5 </ b> B, every other four support columns among the eight support columns 5 </ b> B. It is provided close to 5B. However, the gap balls 6 may be provided in correspondence with all the columns 5, and in which place the gap balls 6 are provided may be determined as appropriate.

[Explanation of tension member]
In the vicinity of the place where the column 5 is supported, a tension member 7 that biases the face plate 3 downward is provided in the vicinity. The tension member 7 is not necessarily provided in the vicinity of all the support portions by the support column 5, but the support member 5 is indispensable at a location where the gap ball 6 and the tension member 7 are used in combination. The support column 5 can be used alone or in a place where either the gap ball 6 or the tension member 7 is present in the vicinity.

  In FIG. 4, the base plate 2 is provided with a third through hole 2C, and the face plate 3 is provided with a third attachment hole 3C at a position corresponding to the third through hole 2C. The third through-hole 2C has a stepped shape having a counterbore portion from below, and the third attachment hole 3C has a stepped shape having a counterbore portion from above.

  The tension member 7 is inserted into the shaft 71 inserted through both the third through hole 2C of the base plate 2 and the third attachment hole 3C of the face plate 3, and the shaft 71 protruding downward from the third through hole 2C. 3 A washer 72 located in the through-hole 2C, a coil spring 73 that is also inserted through the shaft 71 and located below the washer 72, and is inserted through the shaft 71 to contact the lower surface of the base plate 2. A washer 74 and a nut 75 screwed into the male screw portion 76 on the lower side of the shaft 71.

  The washer 72 is pushed up to the stepped portion in the third through hole 2 </ b> C via the washer 74 and the coil spring 73 by tightening the nut 75, and comes into contact therewith. The coil spring 73 is a compression spring. The coil spring 73 is provided on the base plate 2 side and disposed between the coil spring 73 and the nut 75, so that the coil spring 73 is compressed by further tightening of the nut 75. After the nut 75 is screwed in until the washer 74 comes into contact with the lower surface of the base plate 2, the nut 75 is further tightened so that the washer 74 and the nut 75 on the lower side of the shaft 71 are moved downward by the reaction force of the compressed coil spring 73. The entire shaft 71 is urged downward.

  In the third mounting hole 3 </ b> C of the face plate 3, a flange-shaped head portion 77 provided at the upper end of the shaft 71 is locked to the step portion, and the face plate 3 is biased downward via the head portion 77. . That is, according to the tension member 7, the face plate 3 is pulled downward from the base plate 2 side, and there is no portion protruding from the upper surface of the face plate 3. Therefore, the tension member 7 does not interfere with the wafer W regardless of the downward placement of the wafer W on the face plate 3.

  With the structure described above, the lower face of the face plate 3 is supported by the second support ball 55 of the support column 5 while being pulled downward by the tension member 7. Is suppressed, and upward convex deformation due to thermal expansion is also suppressed. As a result, the flatness of the face plate 3 can be maintained with high accuracy, and the wafer W can be reliably placed at an appropriate position. Further, since the tension member 7 does not protrude from the upper surface of the face plate 3 and the aluminum substrate 31 constituting the face plate 3 is thinned, the entire heating device 1 is also thinned.

[Description of gap ball holding structure]
Based on FIG. 5, the holding structure of the gap ball 6 will be described.
The gap ball 6 is press-fitted and held in the inner wall surface of the second mounting hole 3B that penetrates the face plate 3. Specifically, the gap ball 6 is held only by the inner wall surface corresponding to the second mounting hole 3B in the aluminum substrate 31, and the holding position of the gap ball 6 in the second mounting hole 3B is aluminum. In the present embodiment, the gap ball 6 having a diameter larger than the thickness of the aluminum substrate 31 is press-fitted into a position slightly higher than the center in the thickness direction. In addition, a predetermined protrusion amount of the gap ball 6 is ensured.

  The gap ball 6 is press-fitted from above into the second mounting hole 3B. At this time, the surface of the anodized layer 34 applied to the inner wall surface of the aluminum substrate 31 is thinly removed at the press-fitted portion, but remains. . If the gap ball 6 is pressed into the second mounting hole 3B deeply below the center in the thickness direction of the aluminum substrate 31, the alumite layer 34 will be exposed to all the portions below the press-fitting site by external force from above. It peels off from the inner wall surface and may be lost at once. In this case, the holding force on the lower side of the gap ball 6 is reduced, so that the gap ball 6 cannot be stably held and the gap C cannot be maintained. On the other hand, in the present embodiment, the gap ball 6 is held at a position higher than the center of the aluminum substrate 31 in the plate thickness direction so that the gap C can be maintained more reliably without being lost. Yes.

  Further, according to the present embodiment, by providing the second mounting hole 3B so as to penetrate the aluminum substrate 31, there is no bottom portion formed as a part of the aluminum substrate 31 in the second mounting hole 3B. However, the gap ball 6 is not placed on such a bottom portion. Accordingly, it is possible to eliminate the thermal influence exerted on the gap ball 6 by such deformation at the thin bottom portion. Even if the second mounting hole 3B does not penetrate the aluminum substrate 31 and the bottom portion is present on the aluminum substrate 31, the gap ball 6 may not be in contact with the bottom portion. The influence of the thermal expansion and contraction of the bottom portion on the gap ball 6 can be reduced.

  In addition, since there is no bottom portion formed by the aluminum substrate 31 in the second mounting hole 3B, a sealed space is not formed below the gap ball 6, so that the air in the sealed space expands during heating so that the gap ball 6 is The phenomenon of pushing up does not occur, and the gap C can be maintained well.

[Description of grounding structure with grounding member]
A grounding structure using the grounding member 8 will be described with reference to FIGS. 1, 6, and 7.
1 and 6, a fourth through hole 2D penetrating the front and back is provided in the center of the base plate 2, and a female screw is formed in the fourth through hole 2D. A screw hole 2E is provided at a position spaced apart from the fourth mounting hole 2D of the base plate 2 by a predetermined dimension.
On the other hand, at a position corresponding to the fourth through hole 2D of the face plate 3, a fourth mounting hole 3D penetrating the front and back is provided.

  A holding bolt 81 is screwed into the fourth through hole 2D of the base plate 2 from above. The holding bolt 81 has a male screw portion 82 that is screwed into the fourth through hole 2 </ b> D, and a columnar head portion 83 that is integrally provided at the upper end of the male screw portion 82. A guide hole 81 </ b> A penetrating along the axial direction is provided in the center of the holding bolt 81. The portion of the guide hole 81A corresponding to the head 83 is wider in the radial direction than the portion corresponding to the male screw portion 82, and is a holding portion 81B having a hexagonal shape in plan view.

  A hexagonal nut 89 is fitted to the holding portion 81B so as to be slidable up and down. A long screw 84 inserted from above into the fourth mounting hole 3 </ b> D of the face plate 2 is screwed into the nut 89. The long screw 84 is provided at the lower end side and is inserted into the guide hole 81A of the holding bolt 81, the rod part 84A, the male screw part 84B integrally provided at the upper end of the rod part 84A and screwed into the nut 89, It has a head portion 84 </ b> C that is integrally provided at the upper end of the male screw portion 84 </ b> B and is locked by a spot facing portion in the fourth mounting hole 3 </ b> D of the face plate 3. Such a long screw 84 passes through one end side (upper end side) of the ground member 8 interposed between the lower surface of the face plate 3 and the nut 89.

  As shown in FIGS. 6 and 7, the ground member 8 is a metal strip having conductivity such as stainless steel, and the first to fourth bent portions 8A, 8B, 8C, It is formed in a staircase shape having 8D. One end side of the ground member 8 is provided with an insertion hole 8E through which the long screw 84 is inserted, and the other end side (lower end side) is provided with an insertion hole 8F through which the screw 85 is inserted. The screw 85 is screwed into the screw hole 2E so that the other end side of the ground member 8 is sandwiched between the upper surface of the base plate 2 and the washer 86.

  On one end side of the ground member 8, a conductive metal washer 87 is disposed between the lower surface of the face plate 3 and the ground member 8, and is inserted through a long screw 84. The portion of the film heater 32A (FIG. 2) that faces the washer 87 is an opening that is slightly larger than the diameter of the washer 87, and the aluminum substrate 31 (FIG. 2) is also a portion that is also slightly larger than the diameter of the washer 87. The alumite treatment is not applied. And the thickness of the washer 87 is more than the thickness of the insulating layer which consists of the alumite layer 34 and the film heater 32A. As a result, in the state where the long screw 84 is tightened with a predetermined tightening force, the washer 87 is brought into contact with the base portion of the aluminum substrate 41 and becomes conductive, and the ground member 8 is connected to the aluminum substrate via the washer 87. The aluminum substrate 31 is grounded to the base plate 2 through the ground member 8.

  Here, a resin washer 88 having heat insulation and insulation is disposed between the ground member 8 and the nut 89, and is inserted through the long screw 84. Therefore, it is difficult to transfer the heat from the face spray 3 to the nut 89 and the holding bolt 81, and heat transfer can be suppressed. Further, by providing the ground member 8 in the center, even if there is a heat escape, it is less affected from the viewpoint of uniformity than provided at the end.

  In such a ground member 8, the first to fourth bent portions 8 </ b> A to 8 </ b> D are provided in the middle of the longitudinal direction, and thus the external force acting on the ground member 8 is the first to fourth bent portions 8 </ b> A. Absorbed by bending at ˜8D, reaction force against external force hardly occurs at both ends of the ground member 8. Accordingly, the lower surface of the face plate 3 is not pressed upward particularly through the one end side of the ground member 8, and it is possible to prevent the center plate of the face plate 3 from being deformed so as to be pushed upward. Moreover, according to the earth member 8, the bending along the first to fourth bent portions 8A to 8D can cope with the displacement along the longitudinal direction due to the thermal expansion and contraction of the earth member 8.

  In the structure described above, the other end side of the ground member 8 is fixed to the base plate 2 with the screw 85 in the previous step of supporting the face plate 3 on the base plate 2. Further, the nut 89 and the like are also accommodated in the holding portion 81B of the holding bolt 81 screwed into the base plate 2, and one end side of the ground member 8 is positioned above the nut 89 and the washers 87 and 88 are arranged. Keep it.

At the stage of supporting the face plate 3 on the base plate 2, the long screw 84 is inserted into the fourth mounting hole 3 </ b> D of the face plate 3, and at the same time, the ground member 8, the washers 87 and 88, the nut 89, and the holding bolt 81. Insert. Thereafter, when the rod portion 84A of the long screw 84 is rotated while being guided in the guide hole 81A of the holding bolt 81, the nut 89 is screwed into the long screw 84 and slides upward in the holding portion 81 without rotating. Finally, the ground member 8 and the washers 87 and 88 are sandwiched between the lower surface of the face plate 3 and the nut 89.

[Description of terminal block and terminal]
In FIG. 8, the terminal block 9 includes an insulating resin base 91 fixed to the lower surface of the base plate 2, and a conductive pair of metal conductive plates 92 attached to the base 91. And a pressing member 93 attached to the outer end of the conduction plate 92.

  The outer edge of the base 91 is substantially flush with the end surface of the base plate 2. The base 91 is provided with two mounting grooves 91A along the inner and outer directions (same as the radial direction of the base plate 2), and the conduction plate 92 is disposed in the mounting groove 91A. At the center in the longitudinal direction of the mounting groove 91A and the conduction plate 92, through holes 91B and 92A penetrating the front and back are provided. A cylindrical member 94 made of resin having insulation properties is inserted into the through holes 91B and 92A.

A screw 96 passed through a flat washer 95 and a spring washer 95 ′ is inserted into the cylindrical member 94, and the screw 96 is screwed into a screw hole 2 </ b> F provided in the base plate 2. With this screw 96, the base 91 is fixed to the base plate 2, and the conduction plate 92 is attached to the base 91. At this time, the screw 96 screwed into the base plate 2 is insulated from the conductive plate 92 by being inserted into the cylindrical member 94, so that the conductive plate 92 is not electrically connected to the base plate 2.

  In the conduction plate 92, screw holes 92B are provided on both sides of the through hole 92A, and screws 97 are screwed into the screw holes 92B. The base 92 is provided with a round hole 91C at a position corresponding to the screw hole 92B. The round hole 91C is for avoiding interference between the tip of the screw 97 protruding from the screw hole 92B and the base 91. It is a hole.

A screw 97 screwed inwardly of the conduction plate 92 is inserted into the crimp terminal 24A of the wiring 24 through a flat washer 98 and a spring washer 98 '. By screwing the screw 97 into the screw hole 92 </ b> B, the wiring 24 is connected onto the conduction plate 92.
A screw 97 screwed on the outer side of the conduction plate 92 is inserted into the holding member 93 via a flat washer 98 and a spring washer 98 ', and is inserted into the terminal 33 of the film heater 32A (FIG. 2). . By screwing the screw 97 into the screw hole 92 </ b> B, the terminal 33 is connected to the conduction plate 92 so as to be pressed by the pressing member 93.
In FIG. 8, the base plate 2 and the terminal block 9 are shown as viewed from below. However, the operation of attaching the terminal block 9 to the base plate 2 and the operation of connecting the wiring 24 and the terminal 33 are performed on the base plate 2. This is done with the bottom side up.

  The terminal 33 connected to the terminal block 9 has a channel shape (a U shape) having first and second bent portions 33A and 33B in the middle of the longitudinal direction. Therefore, by having the first and second bent portions 33A and 33B, the external force acting on the terminal 33 is caused by the bending at the first and second bent portions 33A and 33B, similarly to the ground member 8 described above. Absorbed, the reaction force against the external force hardly occurs at both ends of the terminal 33. Accordingly, the lower surface of the face plate 3 is not pressed upward or pulled downward, particularly via the base end side of the terminal 33, and the outer periphery of the face plate 3 is pushed upward or pulled down. Can be prevented from being deformed. Further, even if the face plate 3 is pushed up or pulled down for some reason, the terminals 33 are arranged at equal intervals, so that they are not deformed into irregular shapes and the influence of the deformation can be reduced. .

Further, since the terminal block 9 is attached to the lower surface of the base plate 2, the work of connecting the terminals 33 can be facilitated by turning the lower surface of the base plate 2 upward, and the workability is good.
In addition, the terminal block 9 is conventionally attached to the upper surface of the base plate 2 and accommodated in the space between the face plate 3, but by being attached to the lower surface of the base plate 2, the base play 2, the face plate 3, , And the overall thickness reduction of the heating device 1 can be promoted.

It should be noted that the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
For example, in the above-described embodiment, the tension members 7 are provided in the vicinity of all the support portions by the support column 5, but the tension members 7 are not only in the vicinity of all the support portions but only in the vicinity of some appropriately selected support portions. Even when the member 7 is provided, it is included in the present invention, and the case where the tensile member 7 is provided in a place other than the vicinity of the support place in the support column 5 is also included in the present invention. In short, it is only necessary that the portion of the face plate 3 corresponding to the wafer W mounting region is urged downward by the tension member 7 from the base plate 2 side.

In the above embodiment, the film heater 32A is used as the heating means according to the present invention, but it is not necessary to use the film heater as long as the circuit pattern for heat generation can be formed on the substrate itself.
In the above embodiment, the coil spring 73 is used as the biasing means for the tension member 7, but it may be a columnar rubber member having elasticity.
In the above-described embodiment, the gap ball 6 is used as the wafer support means. However, the present invention is not limited to this. For example, a substantially conical protrusion that tapers toward the upper end may be used.

In the said embodiment, although the shape of the earth member 8 is a linear form extended toward the radial direction outer side from the center of the heating apparatus 1 in planar view, it is not limited to such a shape. For example, as shown in FIGS. 9A and 9B, the extending direction may be changed by 90 degrees at the second bent portion 8B to form an L shape in plan view. As shown in A) and (B), in addition to the second bent portion 8B, the extension direction is changed again by 90 ° at the fourth bent portion 8D to form a crank shape in plan view. May be.
In the ground member 8 having these shapes, the first and second bent portions 8A and 8B are bent, and the third and fourth bent portions 8C and 8D are bent, so that they are orthogonal to each other. Can cope with displacement in direction.

  The present invention can be used for heating a semiconductor wafer.

  DESCRIPTION OF SYMBOLS 1 ... Heating device, 2 ... Base plate, 3 ... Face plate, 5 ... Support | pillar, 6 ... Gap ball which is wafer support means, 7 ... Tensile member, 8 ... Ground member, 8A, 8B, 8C, 8D ... Bending part, DESCRIPTION OF SYMBOLS 9 ... Terminal block, 11 ... Cooling pipe, 12 ... Thermal insulation rectifying plate, 24 ... Wiring, 32, 32A ... Film heater which is heating means, 33 ... Terminal, 71 ... Shaft, 73 ... Compression spring which is urging means Coil spring, 75 ... nut, 81 ... holding bolt, 81A ... guide hole, 81B ... holding part, 83 ... head, 84 ... long screw, 84A ... rod part, 84B ... male screw part, 87 ... washer, 89 ... nut , W ... wafer.

Claims (5)

A conductive base plate;
A face plate on which a wafer is placed above the base plate;
A grounding member disposed between the base plate and the face plate to conduct each other;
The face plate is
An aluminum substrate whose surface is electrically insulated except for a conductive portion with the ground member;
Heating means provided on the aluminum substrate for heating the wafer;
The conductive portion of the aluminum substrate with the ground member is provided at the center of the aluminum substrate,
In the middle of the longitudinal direction of the ground member, a plurality of bent portions are provided. The heating device according to claim 1,
A conductive washer is interposed between the conductive portion of the aluminum substrate and the end of the ground member,
The thickness of the said washer is more than the thickness of the insulating layer around the said conduction | electrical_connection part. The heating apparatus characterized by the above-mentioned. In the heating device according to claim 1 or 2,
In the center of the base plate, a holding bolt having a guide hole penetrating along the axial direction is screwed,
In the center of the face plate, a long screw having a lower end side which is a lot portion inserted into the guide hole and an upper end side which is a male screw portion which is screwed into a nut provided on the head of the holding bolt is inserted. A heating device characterized by that. The heating device according to claim 3, wherein
The heating device, wherein the head of the holding bolt is provided with a holding portion in which the nut is slidably fitted up and down in a non-rotating state. A base plate;
A face plate on which a wafer is placed above the base plate;
A cooling pipe provided between the base plate and the face plate, through which a refrigerant gas for cooling the face plate flows;
A heat-insulating rectifying plate that is provided between the base plate and the face plate, guides the refrigerant gas ejected through the cooling pipe, and shields radiant heat from the face plate to the base plate;
Wafer support means provided protruding from the upper surface of the face plate;
A terminal block attached to the base plate, to which wiring from an external power source is connected;
A plurality of columns that are erected between the base plate and the face plate to support the face plate;
A plurality of tension members for pulling the face plate toward the base plate;
A grounding member disposed between the base plate and the face plate to conduct each other;
The face plate is
An aluminum substrate whose surface is electrically insulated except for a conductive portion with the ground member;
A heating unit provided on the aluminum substrate for heating the wafer and having a power feeding terminal connected to the terminal block,
The conductive portion of the aluminum substrate with the ground member is provided at the center of the aluminum substrate,
In the middle of the longitudinal direction of the ground member, a plurality of bent portions are provided.

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