JP2004072095A - Hot plate unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hot plate unit that can be cooled down in a short time without causing complication or size enlargement of a structure. <P>SOLUTION: This hot plate unit 1 has a hot plate 3 having a resistor 10 installed at an opening 4 of a casing 2. The hot plate 3 has a fluid cooling down the hot plate 3 and a space S1 that is constituted in such a manner as to freely circulate this fluid. This space S1 is formed between the inner side of the casing 2 and the lower side of the hot plate 3. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a hot plate unit.
[0002]
[Prior art]
In a semiconductor manufacturing process, for example, when heating and drying a silicon wafer that has undergone 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, for example, there is one disclosed in Patent Document 1. The device disclosed in Patent Document 1 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]
Then, 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.
[0005]
[Patent Document 1]
Japanese Patent Publication No. 4-13837 [0006]
[Problems to be solved by the invention]
When the photosensitive resin is dried by heating the resistor for a predetermined period of time by energizing the resistor, it is necessary to first cool the hot plate to a somewhat lower temperature, and then remove the silicon wafer. However, it takes a certain amount of time to cool, and this is an obstacle to improving the productivity.
[0007]
Therefore, for example, a countermeasure can be considered in which a cooling pipe is provided on the lower surface side of the plate and cooling water is passed through the pipe to forcibly cool the plate to reduce the cooling time. However, such measures may not only complicate the entire structure of the unit but also increase the size and size of the unit.
[0008]
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 that can be cooled in a short time without complicating the structure or increasing the size.
[0009]
[Means for Solving the Problems]
In order to solve the above problem, the invention according to claim 1 is a hot plate unit in which a hot plate having a resistor is installed in an opening of a casing, and a fluid for cooling the hot plate is provided. The hot plate unit is characterized in that it has a space configured to allow the fluid to flow freely, and the space is formed between the inside of the casing and the lower portion of the hot plate. .
According to the second aspect of the present invention, there is provided a hot plate unit in which a hot plate having a resistor is provided at an opening of a casing, wherein a space through which a fluid can flow is constituted by the casing and the hot plate. The gist is a hot plate unit characterized in that:
[0010]
According to a third aspect of the present invention, in the first or second aspect, the casing is provided with a fluid supply port for supplying the fluid by communicating the inside and the outside thereof.
[0011]
According to a fourth aspect of the present invention, in any one of the first to third aspects, the casing is provided with a discharge hole for discharging a fluid supplied from a fluid supply port from the space.
[0012]
According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the casing is provided with a fluid discharge port for discharging a fluid supplied from a fluid supply port from the space. .
[0013]
According to a sixth aspect of the present invention, in any one of the third to fifth aspects, the fluid supply port is provided on a side wall and / or a bottom of the casing.
[0014]
According to a seventh aspect of the present invention, in any one of the fourth to sixth aspects, the discharge hole or the fluid discharge port is provided on a side wall and / or a bottom of the casing.
[0015]
According to an eighth aspect of the present invention, in any one of the fifth to seventh aspects, the fluid supply port and the fluid discharge port are provided on a side wall and / or a bottom of the casing.
[0016]
In a ninth aspect of the present invention, in any one of the third to eighth aspects, the casing includes a plurality of at least one of the fluid supply port and the fluid discharge port.
[0017]
According to a tenth aspect of the present invention, in any one of the fourth to ninth aspects, the casing includes a plurality of at least one of the fluid supply port and the discharge hole.
[0018]
According to an eleventh aspect of the present invention, in any one of the third to tenth aspects, the hot plate is formed of a plate-shaped base material, and the fluid supplied from the fluid supply port is supplied to the plate-shaped base material. It was made to flow while contacting the lower surface side.
[0019]
According to a twelfth aspect of the present invention, in any one of the first to eleventh aspects, the fluid is air or an inert gas.
According to a thirteenth aspect, in any one of the first to twelfth aspects, the hot plate is made of ceramic.
[0020]
According to a fourteenth aspect of the present invention, in any one of the first to thirteenth aspects, the hot plate is formed by forming a resistor on a lower surface side of a ceramic plate-shaped base material.
Hereinafter, the “action” of the present invention will be described.
[0021]
According to the first to fourteenth aspects of the present invention, it is possible to forcibly cool the hot plate by flowing the fluid through the space, and it can be completed in a shorter time than 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.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a hot plate unit 1 according to an embodiment of the present invention will be described in detail with reference to FIGS.
[0023]
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. On the outer peripheral portion of the bottom portion 2a, a lead wire drawing hole 7 for inserting a lead wire 6 for supplying a current to the hot plate 3 is formed.
[0024]
The hot plate 3 of the present embodiment is a low-temperature hot plate 3 for drying the silicon wafer W1 coated with the photosensitive resin at 200 to 300 ° 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 substrate 9 is installed in the opening 4 of the casing 2 via a seal ring 14 described later. 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.
[0025]
Here, the thickness of the unit 1 is preferably set to 5 mm to 100 mm, and particularly preferably set to 10 mm 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.
[0026]
As shown in FIG. 1, the plate-like base material 9 constituting the hot plate 3 has a circular shape and is designed to have a diameter slightly smaller than the outer dimensions of the casing 2. 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.
[0027]
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.
[0028]
The wiring resistor 10 of the present embodiment is formed by baking a conductive paste on the plate-shaped 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 include, for example, gold, silver, platinum, palladium, lead, tungsten, nickel and the like. 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.
[0029]
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, a socket 6a at the tip of the lead wire 6 is fitted to the tip of each terminal pin 12. 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.
[0030]
As shown in FIG. 2, a plurality of screw holes 13 are provided at equal intervals in the upper edge of the opening 4 of the casing 2. 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.
[0031]
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 periphery of the lower surface of the hot plate 3, thereby preventing air from flowing through the gap. Is responsible for.
[0032]
As shown in FIGS. 1 and 2, a locking ring 21 is fixed to the upper surface of the seal ring 14 with a screw 25. The locking ring 21 has an annular main body 22, a plurality of screw holes 23, and a plurality of locking pieces 24. The hot plate 3 set on the supporting step 16 is pressed by the locking pieces 24 from the plate thickness direction, and is clamped and fixed to the seal ring 14.
[0033]
As shown in FIG. 1, a fluid supply port 17 and a fluid discharge port 18 are provided on the bottom 2 a of the casing 2 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.
[0034]
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.
[0035]
As shown in FIG. 2, a seal packing 8 as a seal structure is mounted in the above-mentioned lead wire 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 has a role of sealing the gap formed between each lead wire 6 and the lead wire drawing hole 7 to prevent air from flowing through the gap.
[0036]
Now, a method of using the hot plate unit 1 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, the temperature of the silicon wafer W1 gradually increases due to the contact with the heated hot plate 3. When the photosensitive resin is sufficiently dried by heating for a predetermined time, the power supply to the wiring resistor 10 is stopped.
[0037]
Here, the gas pressure pump is driven to supply cooling air to the fluid supply port 17 side, and the air is introduced into the closed space S1 through the port 17. 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.
[0038]
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.
[0039]
On the other hand, in the conventional device, if a terminal is provided on the lower surface side of the plate and wiring is to be pulled out therefrom, a projection exists on the lower surface side of the device, and mounting on the support stage becomes difficult. Become.
[0040]
(2) Further, since the space S1 formed between the casing 2 and the hot plate 3 is substantially sealed, 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.
[0041]
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. On the other hand, in the countermeasure of forcibly cooling the plate by blowing air to the lower surface side of the hot plate, the surroundings of the apparatus may be contaminated by moisture and dust contained in the air.
[0042]
In addition, according to the configuration of the present embodiment, since there is no need to provide a cooling pipe or the like, there is no concern that the entire structure of the 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.
[0043]
(4) In this hot plate unit 1, a seal ring 14 is provided 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 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.
[0044]
(5) Further, in the hot plate unit 1, a seal packing 8 is further provided in the wiring drawing hole 7 in the bottom 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.
[0045]
(6) In the present embodiment, since the thickness of the unit 1 is set within a preferable range of 10 mm to 100 mm, 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.
[0046]
If the sealability 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. 3 may be attached. That is, the hot plate 3 can be directly attached to the casing 2.
[0047]
The wiring lead-out hole 7 serving as a wiring lead-out portion may be provided at a location other than the bottom 2 a of the casing 2, for example, at a side wall of the casing 2. Similarly, the ports 17 and 18 may be provided 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.
[0048]
A gas other than air (air), for example, an inert gas such as carbon dioxide or nitrogen, can flow as a cooling fluid in the closed space S1 defined by the casing 2. 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. Air and inert gas have low reactivity, do not cause a risk of short-circuit between resistors, and are advantageous in reducing costs.
[0049]
A thermocouple may be embedded in the plate-shaped base material 9 constituting the hot plate 3 as necessary. This is because the temperature can be controlled by measuring the temperature of the hot plate 3 with a thermocouple and 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.
[0050]
As in another example of the hot plate unit 1 shown in FIG. 3, the fluid discharge port 18 may be omitted from the casing 2 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.
[0051]
-You may comprise like the hot plate unit 1 of another example shown in FIG. That is, here, the casing 2A having no bottomed shape is used. Inside such a bottomless casing 2A, a metal middle bottom plate 41 having an exhaust hole 31 as an opening 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 can escape from the gap between the casing 2A and the midsole plate 41 to the outside. An opening may be formed in the midsole plate 41.
[0052]
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), 4 parts by weight of yttrium oxide (Y ₂ O ₃ : yttria, average particle size 0.4 μm), acrylic resin binder (Mitsui Chemicals) SA-545 (acid value 0.5) 12 parts by weight were mixed and put into a molding die to obtain a molded product.
[0053]
(2) The molded body was heated in a nitrogen atmosphere at 350 ° C. for 4 hours to thermally decompose the acrylic resin binder.
(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.
[0054]
(4) A conductive paste was printed on the bottom surface of the sintered body obtained in (3) 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 conductor 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 composed of alumina (5% by weight).
[0055]
(5) Next, the sintered body on which the conductive paste was printed was heated and fired at 780 ° C. to sinter silver and lead in the conductive paste, and baked on the sintered body to form a heating element. The silver / lead heating element had a thickness of 5 μm, a width of 2.4 mm, and a sheet resistivity of 7.7 mΩ / □.
[0056]
(6) An electroless nickel plating bath comprising an aqueous solution containing 80 g / l of nickel sulfate, 24 g / l of sodium hypophosphite, 12 g / l of sodium acetate, 8 g / l of boric acid, and 6 g / l of ammonium chloride as described in (4) above. The produced sintered body was immersed, and a metal coating layer (nickel layer) having a thickness of 1 μm was deposited on the surface of the tin / lead (9/1) heating element to obtain a wiring resistance of 10.
[0057]
(7) A silver / lead solder paste (manufactured by Tanaka Kikinzoku) was printed by screen printing on a portion to which a terminal for securing connection to a power supply was attached, to form a solder layer. Next, 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 heating element connection pads 10a.
[0058]
(8) A thermocouple for temperature control was inserted into the bottomed hole, filled with a polyimide resin, and cured at 190 ° C. for 2 hours to obtain a hot plate 3. This hot plate 3 was incorporated in the unit of FIG. The seal ring 14 used a fluorine resin. After the temperature of the unit 1 was raised to 140 ° C., air was supplied from the supply port to measure the cooling time to 90 ° C., and it was 3 minutes. Further, as a comparative example, when the hot plate 3 manufactured in (1) to (8) was brought into contact with an aluminum plate having an air flow path therein, and cooled to 90 ° C., it took 8 minutes. .
[0059]
【The invention's effect】
As described in detail above, according to the first to fourteenth aspects of the present invention, it is possible to provide a hot plate unit that can be cooled in a short time without complicating the structure or increasing the size.
[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 symbols]
DESCRIPTION OF SYMBOLS 1 ... Hot plate unit, 2, 2A ... Casing, 3 ... Hot plate, 4 ... Opening, 7 ... Wiring lead-out hole as a wiring lead-out part, 17 ... Fluid supply port, 18 ... Fluid discharge port, 31 ... Discharge hole Exhaust hole, 41 ... middle bottom plate, S1 ... space.

Claims (14)

A hot plate unit in which a hot plate having a resistor is installed in an opening of the casing,
A fluid for cooling the hot plate and a space configured to allow the fluid to flow therethrough, wherein the space is formed between the inside of the casing and the lower portion of the hot plate. Hot plate unit. A hot plate unit in which a hot plate having a resistor is installed in an opening of the casing,
A hot plate unit, wherein a space through which a fluid can flow is constituted by the casing and the hot plate. 3. The hot plate unit according to claim 1, wherein the casing is provided with a fluid supply port that supplies the fluid by communicating the inside and the outside thereof. 4. The hot plate unit according to claim 1, wherein the casing is provided with a discharge hole for discharging a fluid supplied from a fluid supply port from the space. The hot plate unit according to any one of claims 1 to 4, wherein the casing is provided with a fluid discharge port for discharging a fluid supplied from a fluid supply port from the space. The hot plate unit according to claim 3, wherein the fluid supply port is provided on a side wall and / or a bottom of the casing. The hot plate unit according to claim 4, wherein the discharge hole or the fluid discharge port is provided on a side wall and / or a bottom of the casing. The hot plate unit according to claim 5, wherein the fluid supply port and the fluid discharge port are provided on a side wall and / or a bottom of the casing. The hot plate unit according to claim 3, wherein the casing includes a plurality of at least one of the fluid supply port and the fluid discharge port. The hot plate unit according to claim 4, wherein the casing includes a plurality of at least one of the fluid supply port and the discharge hole. The said hot plate is comprised by a plate-shaped base material, and makes the fluid supplied from the said fluid supply port distribute | circulate, making the lower surface side of the said plate-shaped base material contact. Item 2. The hot plate unit according to item 1. The hot plate unit according to any one of claims 1 to 11, wherein the fluid is air or an inert gas. The hot plate unit according to claim 1, wherein the hot plate is made of ceramic. 14. The hot plate unit according to claim 1, wherein the hot plate is formed by forming a resistor on a lower surface side of a ceramic plate-shaped base material.

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