JP3497463B2 - Hot plate unit for semiconductor manufacturing equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot plate unit for a semiconductor manufacturing apparatus . 2. Description of the Related Art In a semiconductor manufacturing process, for example, when heating and drying a silicon wafer after a photosensitive resin coating step, a heating device called a hot plate is usually used. [0003] As a conventional example of this type of apparatus, there is, for example, one disclosed in Japanese Patent Publication No. 4-13837.
The apparatus disclosed in the publication includes a hot plate made of an aluminum nitride sintered body as an electric heating member, and a resistor provided on the plate. The resistor is sandwiched between ceramic substrates constituting a hot plate. Both ends of the resistor protruding to the side of the plate are respectively connected to a power supply via wiring. [0004] A silicon wafer to be heated is placed on the upper surface side of the hot plate, and a current is applied to the resistor in this state, whereby the silicon wafer is heated to several hundred degrees Celsius. When the photosensitive resin is dried by heating the resistor for a predetermined period of time by energizing the resistor, the hot plate is first cooled to a somewhat lower temperature, and then cooled. It is necessary to remove the silicon wafer. However, it takes a certain amount of time to cool, and this is an obstacle to improving the productivity. Therefore, for example, a countermeasure may be taken to provide a cooling pipe on the lower surface side of the plate and pass cooling water through the pipe, thereby forcibly cooling the plate to reduce the cooling time. However, with such measures,
Not only is the structure of the whole unit complicated, but also the unit may be bulky and large. [0007] A countermeasure to reduce the cooling time by forcibly cooling the plate by blowing air on the lower surface side of the hot plate is also conceivable. However, with such a measure, the surroundings of the device may be contaminated by moisture or dust contained in the air, which is not feasible at present. The present invention has been made in view of the above problems, and an object of the present invention is to provide a hot plate unit for a semiconductor manufacturing apparatus which can be cooled in a short time without complicating the structure or increasing the size. It is in. According to the first aspect of the present invention, a ceramic hot plate having a resistor is provided at an opening of a casing. A hot plate unit, wherein the cable
A fluid supply port for supplying a cooling fluid to the thing,
Fluid discharge port or cooling flow for discharging cooling fluid
It has an opening for discharging the body and for cooling
Fluid can flow space is constituted by said hot plate and the casing, the wire lead portion in the casing, the hot plate unit for a semiconductor manufacturing apparatus characterized by seal structure is provided This is the gist. Hereinafter, the "action" of the present invention will be described. According to the present invention, it is possible to forcibly cool the hot plate by flowing the fluid through the space formed by the casing and the hot plate, and it is possible to perform the cooling in a shorter time than the cooling. In addition, since there is no need to provide a cooling pipe or the like, there is no fear that the structure of the entire unit becomes complicated or bulky and large. Moreover,
By sealing the wiring lead-out portion in the casing, leakage of the fluid to the outside of the device through the portion is prevented, and higher airtightness is secured in the space. Further, since the drawn wiring does not directly rub against the opening edge of the wiring drawing portion, damage to the wiring is reduced, and the reliability of the device is improved. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a hot plate unit 1 according to an embodiment of the present invention will be described in detail with reference to FIGS. The hot plate unit 1 shown in FIGS. 1 and 2 includes a casing 2 and a hot plate 3 as main components. The casing 2 is a bottomed metal member (in this case, an aluminum member), and has an opening 4 having a circular cross section on an upper side thereof. Pin insertion sleeves 5 through which lift pins (not shown) are inserted are provided at three places at the center of the bottom 2 a of the casing 2. These lift pins raise and lower the silicon wafer W1 while supporting the silicon wafer W1 at three points. A hot plate 3 is provided on the outer periphery of the bottom 2a.
Is formed with a wire drawing hole 7 for inserting a lead wire 6 for supplying a current to the wire. The hot plate 3 of the present embodiment is provided with a silicon wafer W1 on which a photosensitive resin is applied.
This is a low-temperature hot plate 3 for drying at a temperature of 0 ° C. This hot plate 3 is configured by providing a wiring resistance 10 as a resistor on a plate-like base material 9 made of a ceramic sintered body. The plate-shaped base material 9 is connected to the opening 4 of the casing 2 via a seal ring 14 described later.
Installed in By installing this, a substantially sealed space S1 is formed between the inner surface side of the casing 2 and the lower surface side of the hot plate 3. Here, the thickness of the unit 1 is 5 mm to 10 mm.
It is often set to 0 mm, especially 10 mm ~
It may be set to 50 mm. The reason is that if the unit 1 is too thick, the whole becomes bulky and large. Conversely, if the unit 1 is to be made thinner, the hot plate 3 and the casing 2 must be made thinner, which may make production difficult. In the present embodiment, the thickness is set to 20 mm in consideration of the above. [0015] As shown in FIG.
Is formed in a circular shape, and the casing 2
It is designed to have a slightly smaller diameter than the external dimensions of.
The wiring resistor 10 is formed concentrically or spirally on the lower surface side of the plate-shaped base material 9. In the center of the hot plate 3, pin insertion holes 11 are provided at three positions corresponding to the respective lift pins. As the ceramic sintered body constituting the plate-shaped substrate 9, it is preferable to select a nitride ceramic sintered body having excellent heat resistance and high thermal conductivity.
As the nitride ceramic, for example, a sintered body of a metal nitride ceramic such as aluminum nitride, silicon nitride, boron nitride, titanium nitride or the like is preferable, and among them, an aluminum nitride sintered body is desirable. The reason is that the thermal conductivity is the highest in the above-mentioned sintered body. In addition to these, a sintered body of a metal carbide ceramic such as silicon carbide, zirconium carbide, titanium carbide, tantalum carbide, tungsten carbide, or the like may be selected. The wiring resistor 10 of the present embodiment is formed by baking a conductive paste on a plate-like base material 9 which is a sintered body. As the conductive paste, those containing metal particles, metal oxides, resins, solvents and the like are generally used. Suitable metal particles used for the conductive paste, for example, gold, silver, platinum, palladium,
Lead, tungsten, nickel and the like can be mentioned. This is because these metals are relatively unlikely to be oxidized even when exposed to a high temperature, and exhibit a sufficiently large resistance value when generating heat by energization. Suitable metal oxides used for the conductive paste include, for example, lead oxide, zinc oxide, silica, boron oxide, alumina, yttria, titania, and the like. As shown in FIG. 2, a pad 10a as an external connection terminal is formed at an end of the wiring resistor 10. The base ends of the terminal pins 12 made of a conductive material are soldered to these pads 10a. As a result, electrical continuity between each terminal pin 12 and the wiring resistor 10 is achieved. On the other hand, at the tip of each terminal pin 12,
A socket 6a at the tip of the lead wire 6 is fitted. Accordingly, a current is supplied to the wiring resistor 10 via the lead wire 6 and the terminal pin 12, and as a result, the temperature of the wiring resistor 10 increases, and the entire hot plate 3 is heated. As shown in FIG. 2, a plurality of screw holes 13 are formed in the upper edge of the opening 4 of the casing 2 at regular intervals. Similarly, a seal ring 14 as a seal structure is disposed on the upper edge of the opening 4. The seal ring 14 has an annular shape and is substantially equal in size to the opening 4. As a material for forming the seal ring 14, for example, an elastic body such as resin or rubber is preferable. A plurality of screw holes 15 are provided at locations corresponding to the respective screw holes 13 in the seal ring 14. On the inner peripheral surface of the seal ring 14, a supporting step 16 for horizontally supporting the outer peripheral portion on the lower surface side of the hot plate 3 is formed over the entire periphery thereof. When the hot plate 3 is supported by the supporting step 16, the height of the upper end surface of the seal ring 14 and the height of the upper surface of the hot plate 3 are substantially the same. The seal ring 14 in the present embodiment seals a gap formed between the upper edge of the opening 4 of the casing 2 and the outer peripheral portion of the lower surface of the hot plate 3 so that air flows through the gap. Has a role to prevent. As shown in FIGS. 1 and 2, on the upper surface of the seal ring 14, a locking ring 21 is fixed by screws 25. The locking ring 21 has an annular main body 22.
And a plurality of screw holes 23 and a plurality of locking pieces 24. The hot plate 3 set on the supporting step 16 is
By being pressed from the plate thickness direction by each locking piece 24, it is clamped and fixed to the seal ring 14. As shown in FIG. 1, a fluid supply port 17 and a fluid discharge port 1 are provided at the bottom 2a of the casing 2.
8 are respectively installed using bolts or the like. In this embodiment, the ports 17 and 18 are disposed at positions separated from each other. Both ports 17 and 18 have flow paths that open on both the inner end face and the outer end face. For this reason, the inside and the outside of the casing 2 are communicated through the flow path. A female screw groove is formed on the inner peripheral surface of the opening on the outer end surface side of the fluid supply port 17, and one end of a fluid supply pipe (not shown) is detachable from the opening. The other end of the pipe is connected to a gas pressure pump, so that air as a cooling fluid is supplied through the pipe. On the other hand, a female screw groove is also formed on the inner peripheral surface of the opening on the outer end surface side of the fluid discharge port 18, and one end of a fluid discharge pipe (not shown) is detachable from the opening. The air in the casing 2 is discharged to the outside through this pipe. The other end of the pipe is open at a location slightly away from the apparatus. As shown in FIG. 2, a seal packing 8 as a seal structure is mounted in the wiring drawing hole 7. The seal packing 8 has an annular shape and is formed of a suitable elastic body such as rubber. Each lead wire 6 is inserted into the through hole of the seal packing 8 and then drawn out of the casing 2. That is, the seal packing 8 in the present embodiment.
Plays a role of preventing the flow of air through the gap by sealing the gap formed between each lead wire 6 and the wiring lead-out hole 7. Next, this hot plate unit 1
How to use will be described. The silicon wafer W1 coated with the photosensitive resin is placed on the hot plate 3, and the wiring resistor 10 is energized in this state. Then, by contact with the heated hot plate 3, the silicon wafer W
The temperature of 1 gradually increases. When the photosensitive resin is sufficiently dried by heating for a predetermined time, the power supply to the wiring resistor 10 is stopped. Here, the gas pressure pump is driven to supply cooling air to the fluid supply port 17 side.
Is introduced into the closed space S1 through the air. The air discharged through the fluid supply port 17 flows toward the fluid discharge port 18 while contacting the lower surface of the hot plate 3 in the closed space S1. At this time, the heat of the hot plate 3 is taken away by the air. The air whose temperature has risen by removing heat flows out of the space again through the fluid discharge port 18 and is discharged to another space where there is no concern about contamination. Note that a series of air flows is schematically indicated by thick arrows in FIG. Then, when the hot plate 3 is cooled down to a somewhat low temperature, the silicon wafer W1 is removed from the hot plate 3. Therefore, according to the present embodiment, the following effects can be obtained. (1) In the hot plate unit 1, the substantially closed space S1 is formed between the casing 2 and the hot plate 3 as described above. Although there are projections such as terminal pins 12 on the lower surface side of the hot plate 3, they are arranged in a space S1 formed between the casing 2 and the hot plate 3. That is, the protrusion is not exposed to the outside of the device, and is in a protected state as it were.
Therefore, the bottom surface of the casing 2 can be attached to the support stage (not shown) without difficulty regardless of the presence of the protrusion. (2) The space S1 formed between the casing 2 and the hot plate 3 is substantially sealed, so that air can be circulated. Therefore, the hot plate 3 can be forcibly cooled by the flow of air into the space S1, and the time required for cooling can be reduced as compared with the case of cooling. Therefore, if this hot plate unit 1 is used, the time required for one drying process is reliably reduced, and the productivity can be improved. Since the space S1 is not in an open state but in a substantially closed state, it is difficult for air to leak out of the apparatus, and there is no risk of contaminating the surroundings. That is, according to the present embodiment, a clean unit 1 can be realized. Further, according to this configuration, since there is no need to provide a cooling pipe or the like, there is no fear that the structure of the entire unit 1 becomes complicated or bulky and large. (3) In the present embodiment, the casing 2 is provided with a fluid supply port 17 and a fluid discharge port 18 that communicate the inside and outside thereof. Therefore, by efficiently circulating the air into the closed space S1 through the ports 17 and 18, the hot plate 3 can be forcibly cooled and returned to a low temperature in a relatively short time. (4) In the hot plate unit 1, the upper edge of the opening 4 of the casing 2 and the hot plate 3
The seal ring 14 is provided between the outer peripheral portion of the lower surface and the outer peripheral portion of the seal member to seal a gap in the portion. Therefore, air leakage to the outside of the device through the gap between the casing 2 and the hot plate 3 is prevented, and higher sealing performance can be secured in the space S1. This contributes to ensuring the prevention of surrounding pollution by air discharge. (5) Further, in the hot plate unit 1, a seal packing 8 is further provided in the wiring drawing hole 7 in the bottom portion 2a, and the lead wire 6 is inserted through the wiring drawing hole 7. Therefore, air leakage to the outside of the device through the wiring lead-out hole 7 is prevented, and higher sealing performance can be secured in the space S1. This also contributes to the prevention of surrounding pollution by air discharge. Furthermore, the lead wire 6 that is drawn out does not directly rub against the opening edge of the wiring drawing hole 7 and is rubbed. For this reason, damage to the lead wire 6 is reduced, and it is possible to prevent the conductor portion of the lead wire 6 from being exposed by the rubbing or the conductor portion from being disconnected. Therefore, the reliability of the device is reliably improved. (6) In this embodiment, since the thickness of the unit 1 is set within the above-mentioned preferred range, it is possible to avoid difficulties in manufacturing and an increase in size. Note that the embodiment of the present invention may be modified as follows. If the hermeticity is ensured to some extent, the seal ring 14 is omitted, and the locking ring 21 is screwed directly to the upper surface of the opening 4 of the casing 2. The hot plate 3 may be attached to the hot plate. That is, the hot plate 3 can be directly attached to the casing 2. A wiring lead-out hole 7 serving as a wiring lead-out part;
May be provided at a place other than the bottom 2 a of the casing 2, for example, on a side wall of the casing 2. Similarly, port 1
7 and 18 may be arranged on the side wall of the casing 2. The number of wiring holes 7 and ports 17 and 18 can be increased or decreased as needed. The closed space S partitioned by the casing 2
A gas other than air (air), for example, an inert gas such as carbon dioxide gas or nitrogen gas, can be circulated as a cooling fluid in 1. In addition, as long as it does not adversely affect the electrical configuration, it is acceptable to allow the liquid to flow as a cooling fluid. A thermocouple may be embedded in the plate-like base material 9 constituting the hot plate 3 as needed. Measure the temperature of the hot plate 3 with a thermocouple,
This is because the temperature can be controlled by changing the voltage value or the current value based on the data. In this case, it is preferable that the lead wire of the thermocouple is also drawn out to the outside via the seal packing 8. As shown in another example of the hot plate unit 1 shown in FIG.
May be omitted and a simple exhaust hole 31 may be used. That is,
The interior of the unit 1 does not necessarily have to be a substantially closed space as in the embodiment (in other words, it may be an open space). According to this configuration, the number of components is reduced, and the structure of the unit 1 is simplified. It may be configured as another example of the hot plate unit 1 shown in FIG. That is, here, the casing 2A having no bottomed shape is used. Inside such a bottomless casing 2A, an exhaust hole 3 as an opening is provided.
1 is provided. The intermediate bottom plate 41 of this another example is fixed to the upper surface of the fixed portion 45 of the casing 2A using screws 43 and nuts 44 while being supported by a substantially U-shaped support fitting 42.
In this alternative structure, the space is not closed. The air flows through the casing 2A and the midsole plate 41.
It is possible to get out of the gap from the gap. An opening may be formed in the midsole plate 41. Here, an example of a manufacturing process of the hot plate 3 of another example of FIG. 4 will be described. (1) 100 parts by weight of aluminum nitride powder (manufactured by Tokuyama Corporation, average particle size 1.1 μm), yttrium oxide (Y
4 parts by weight of ₂ O ₃ : yttria, average particle diameter 0.4 μm) and 12 parts by weight of an acrylic resin binder (SA-545 manufactured by Mitsui Chemicals, acid value 0.5) were mixed and put into a mold to obtain a molded body. . (2) 350 ° C. in a nitrogen atmosphere
By heating for 4 hours, the acrylic resin binder was thermally decomposed. (3) The compact was hot-pressed at 1890 ° C. and a pressure of 150 kg / cm ² for 3 hours to obtain an aluminum nitride sintered body. (4) On the bottom surface of the sintered body obtained in (3),
The conductive paste was printed by screen printing. The printing pattern was a concentric pattern. As the conductive paste, “SOLVEST PS603D” manufactured by Tokurika Kagaku Kenkyusho, which is used for forming through holes in a printed wiring board, was used. This conductive paste is a silver / lead paste, and based on 100 parts by weight of silver, lead oxide (5% by weight), zinc oxide (55% by weight), silica (10% by weight), and boron oxide (25% by weight). And 7.5 parts by weight of a metal oxide comprising alumina and 5% by weight. (5) Next, the sintered body on which the conductive paste is printed is heated and fired at 780 ° C. to obtain silver in the conductive paste,
While sintering the lead, it was baked on a sintered body to form a part of the resistor (heating element). Silver / lead heating elements
5 μm in thickness, 2.4 mm in width, and 7.7 m in sheet resistivity
Ω / □. (6) Nickel sulfate 80 g / l, sodium hypophosphite 24 g / l, sodium acetate 12 g / l,
The sintered body prepared in the above (4) was immersed in an electroless nickel plating bath composed of an aqueous solution containing 8 g / l of boric acid and 6 g / l of ammonium chloride. Then, a metal coating layer (nickel layer) having a thickness of 1 μm was deposited on the surface of the tin / lead heating element to obtain a wiring resistor 10 as a resistor. (7) A silver / lead solder paste (manufactured by Tanaka Kikinzoku Co., Ltd.) was printed by screen printing on a portion where a terminal for securing connection to a power supply was to be formed, to form a solder layer. Next, the terminal pins 12 made of Kovar were placed on the solder layer, and heated and reflowed at 300 ° C. to attach the terminal pins 12 to the surfaces of the connection pads 10a. (8) A thermocouple for temperature control was inserted into the bottomed hole and filled with a polyimide resin, and cured at 190 ° C. for 2 hours to obtain a hot plate 3. Then, the hot plate 3 was incorporated in the unit 1 of FIG.
As a material of the seal ring 14, a fluororesin was used. After the temperature of the unit 1 is raised to 140 ° C., air is supplied from the fluid supply port 17 to 90 °
When the cooling time until the temperature was lowered to ° C. was measured, it was 3 minutes. Further, the hot plate 3 was manufactured according to the above-mentioned procedures (1) to (8), and the hot plate 3 was brought into contact with an aluminum plate provided with an air flow passage therein. This was used as a comparative example. . 140 ° C. for this comparative example
After the temperature was increased until the temperature was lowered to 90 ° C. by flowing air, the cooling time was 8 minutes. Next, in addition to the technical ideas described in the claims, the technical ideas grasped by the above-described embodiments will be listed below together with their effects. (1) In Claim 1, the seal structure provided in the wiring lead-out portion is an annular seal packing made of an elastic body. Therefore, according to the invention described in the technical idea 1, it is difficult to form a gap between the wiring inserted into the seal packing and the wiring lead-out portion, and leakage of the fluid to the outside of the device is more reliably prevented. , Sealing performance is improved. (2) In Claim 1 or the technical idea, the fluid is air (air). Therefore, according to the invention described in the technical idea 2, the reactivity is low, there is no fear of short-circuit between the resistors, and it is advantageous for cost reduction. As described in detail above, according to the first aspect of the present invention, the structure is not complicated and the size is not increased.
A hot plate unit for a semiconductor manufacturing apparatus that can be cooled in a short time can be provided. Further, it can be made even cleaner.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic sectional view showing a hot plate unit according to an embodiment. FIG. 2 is a partially enlarged sectional view of the same. FIG. 3 is a schematic sectional view showing another example of a hot plate unit. FIG. 4 is a schematic sectional view showing another example of a hot plate unit. [Explanation of reference numerals] 1 ... hot plate unit, 2, 2A ... casing,
Reference numeral 3 denotes a hot plate, 4 denotes an opening, 6 denotes a lead wire as a wiring, 7 denotes a wiring drawing hole as a wiring drawing part, 8
... Seal packing as a seal structure, 10 ... Wiring resistance as a resistor, S1 ... Space.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-130830 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/68 H01L 21/027

Claims (1)

(57) in All Claims opening of 1. A casing, cell having a resistor
A hot plate unit provided with a hot plate made of lamic , wherein a cooling flow is provided in the casing.
Fluid supply port to supply body and discharge cooling fluid
Provide a fluid discharge port or an opening to discharge cooling fluid.
A space through which a fluid for cooling can flow is constituted by the casing and the hot plate, and a wiring structure in the casing is provided with a seal structure. Hot plate unit for semiconductor manufacturing equipment.