JP3595150B2 - Temperature control device and temperature control method - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention adjusts and maintains a temperature-controlled object such as a semiconductor wafer placed on the upper surface of the heat plate at a preset high temperature state by operating a heating means configured on the heat plate, The present invention relates to a temperature control apparatus and a method for adjusting a temperature controlled object to a preset low temperature state via a heat plate by cooling a base on which a heat plate is mounted.
[0002]
[Prior art]
In the semiconductor manufacturing process, the semiconductor wafer is heated at 110 to 130 ° C. to remove the solvent remaining in the applied resist film, or the semiconductor wafer is heated to facilitate adhesion between the resist and the substrate before etching. A heating step such as post-baking for heating to 120 to 150 ° C. is included, and a cooling step such as cooling for cooling the heated semiconductor wafer to a room temperature level of about 20 ° C. is included. In this case, it is important to control the temperature of the semiconductor wafer with high responsiveness and high accuracy in order to improve the throughput.
[0003]
As this type of temperature control device, for example, a hollow cooling plate serving as a base, and a heat plate formed of a metal having excellent thermal conductivity such as aluminum, and a heat plate mounted on the upper surface of the cooling plate, In some cases, a fluid circulating supply system for circulating a temperature fluid adjusted to about 20 ° C. is connected to the hollow portion of the cooling plate, and a thin film heater is bonded to the heat plate.
[0004]
In this temperature control device, the wafer is heated to a desired temperature by placing the wafer on the upper surface of the heat plate and operating the thin film heater with the fluid circulation supply system stopped. On the other hand, if the wafer is placed on the upper surface of the heat plate and the fluid circulation supply system is operated from a state where the thin film heater is stopped, the heat plate is cooled to a temperature close to the temperature of the temperature fluid, and the heat of the wafer is further reduced. And the wafer is cooled to the desired temperature.
[0005]
According to this temperature control device, the heating step and the cooling step of the wafer can be performed on the upper surface of the same heat plate, so that not only the space can be saved but also the working efficiency is advantageous. .
[0006]
[Problems to be solved by the invention]
By the way, in the temperature control device as described above, when the thin film heater is operated, the heat of the thin film heater is released from the cooling plate via the heat plate. There is a possibility that thermal responsiveness may be impaired.
[0007]
Moreover, the above-described heat release causes a temperature difference between the upper surface side portion and the lower surface side portion of the heat plate, and causes the heat plate to be deformed outward. In such a case, the gap between the thin-film heater of the heat plate and the wafer is not uniform, so that the wafer has a variation in temperature distribution.
[0008]
Further, in the temperature control device, since the fluid circulation supply system must be stopped while the thin film heater is being operated, that is, the fluid circulation supply system must be intermittently operated, the cooling plate is not required. The time required to cool the wafer to the above temperature is required, and the thermal responsiveness when cooling the wafer may be impaired.
[0009]
An object of the present invention is to provide a temperature control apparatus and a method capable of improving the thermal responsiveness and accurately controlling the temperature of a temperature-controlled object in view of the above circumstances.
[0010]
Means for Solving the Problems and Effects
According to the first aspect of the present invention, there is provided a heat plate which is mounted on a base and constitutes a heating means for adjusting and maintaining a temperature-controlled object placed on an upper surface at a preset high temperature state; A cooling means for cooling the table to adjust and maintain the temperature-controlled object at a preset low temperature state via the heat plate, wherein the heating means is operated. And a separating means for separating the heat plate and the base from each other.
[0011]
According to the first aspect of the present invention, when the heating means is operated, the heat plate and the base are separated from each other by the separation means, so that the heat of the heating means is released from the base. Does not occur.
[0012]
Therefore, according to the first aspect of the present invention, it is possible to improve the thermal responsiveness when heating the object to be temperature-controlled, and furthermore, to prevent the thermal deformation of the heat plate as much as possible to control the temperature. Accurate temperature control of the object becomes possible.
[0013]
In addition, according to the first aspect of the present invention, it is possible to continuously operate the cooling means even while the heating means is operating. Can also improve the thermal response.
[0014]
According to a second aspect of the present invention, in the first aspect of the present invention, the heating means is configured by disposing heaters on both upper and lower surfaces of the heat plate.
[0015]
According to the second aspect of the present invention, the temperature difference between the upper surface side portion and the lower surface side portion of the heat plate can be made as small as possible irrespective of external factors, and the temperature control target It is possible to more accurately control the temperature of the object.
[0016]
According to the invention as set forth in claim 3, as the separation means, the heat plate is disposed so as to be vertically movable so as to penetrate the base, and when the heating means is operated, the heat plate is placed upward with respect to the base. You are applying something to move.
[0017]
According to the third aspect of the present invention, since the high-temperature heat plate is moved apart from the low-temperature base, thermal contact between the two is ensured even when the amount of movement is small. It becomes possible to cut off.
[0018]
In addition, according to the third aspect of the present invention, since the movement of the heat plate is above the base and the separating means is disposed within the installation area of the base, the mounting of the base can be prevented. It is only necessary to secure a space that can be used, and there is no possibility that the apparatus will be enlarged.
[0019]
In the invention according to claim 4, by operating the heating means configured on the heat plate, the temperature-controlled object placed on the upper surface of the heat plate is adjusted and maintained at a preset high temperature state, By cooling the base on which the heat plate is mounted, in the temperature control method of adjusting and maintaining the temperature-controlled object at a preset low temperature state via the heat plate, when operating the heating means, The heat plate and the base are separated from each other.
[0020]
According to the fourth aspect of the invention, since the heat plate and the base are separated from each other when the heating means is operated, the situation in which the heat of the heating means is released from the base does not occur.
[0021]
Therefore, according to the fourth aspect of the present invention, it is possible to improve the thermal responsiveness when heating the object to be temperature-controlled, and further to prevent the thermal deformation of the heat plate as much as possible to control the temperature. Accurate temperature control of the object becomes possible.
[0022]
In addition, according to the fourth aspect of the present invention, since the cooling can be continuously performed even while the heating means is operated, the thermal response at the time of cooling the object to be temperature-controlled is achieved. Characteristics can also be improved.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings showing one embodiment.
1 and 2 conceptually show one embodiment of a temperature control device according to the present invention. The temperature control device exemplified here is:
(1) Wafer cleaning (2) Resist coating (3) Pre-baking (110-130 ° C) + cooling (20 ° C)
(4) Exposure (5) Development (6) Rinse (7) Post baking (120-150 ° C) + cooling (20 ° C)
(8) In a semiconductor manufacturing process of forming a resist film through a process called etching, which is used in the above-described pre-baking + cooling or post-baking + cooling, first, a wafer W to be subjected to a temperature-controlled object is removed. Control is performed such that a cycle of heating to a high temperature (baking) and then cooling the wafer W to room temperature (cooling) is repeated every several tens of seconds for each wafer. That is, the temperature control device has two target temperatures, that is, a target temperature for heating and a target temperature for cooling, and performs control to alternately repeat heating and cooling.
[0024]
As shown in the figure, the temperature control device includes a cooling plate (base) 10 inside the chamber C. The cooling plate 10 is formed by filling a uniform cylindrical member 12 of the same material in a hollow cylindrical case 11 made of a material having high thermal conductivity such as aluminum, and the upper surface of the case 11 is horizontal. Is fixedly installed in the chamber C.
[0025]
The cooling plate 10 has only one discharge pipe 13 at the center of the bottom wall, and has a plurality of inflow pipes 14 at a portion of the bottom wall located around the discharge pipe 13. The discharge pipe 13 and the inflow pipe 14 communicate with each other via the above-described uniform member 12 inside the case 11, and the discharge pipe 13 is connected to the heat storage tank (cooling means) 21 through the discharge passage (cooling means) 20. While being connected to the return port 21a, the plurality of inflow pipes 14 merge with each other, and then to a discharge port 21b of the heat storage tank 21 through a common supply path (cooling means) 23 having a supply pump (cooling means) 22. It is connected. The heat storage tank 21 has a temperature fluid L therein, specifically, a liquid such as a fluorocarbon liquid (= Fluorinert: registered trademark), ethylene glycol, oil, water, or a gas such as nitrogen, air, or helium. By appropriately storing the temperature fluid L in accordance with the target temperature to be controlled and circulating the temperature fluid L with the chiller tank 24, the temperature fluid L is adjusted and maintained at a temperature of about 20 ° C. . Reference numeral 25 in the drawing denotes an opening / closing valve interposed in the supply passage 23.
[0026]
The cooling plate 10 has a plurality of (at least three) spaced-pin insertion holes 15 formed at equal intervals on the same circumference located at the outer peripheral edge thereof, and the spaced-pin insertion holes 15 are formed. A plurality (at least three) of susceptor pin insertion holes 16 are formed on the same circumference, which is located on the inner circumference side with respect to 15 and is smaller in diameter than the wafer W to be processed, and are at equal intervals from each other. The separation pin insertion hole 15 and the susceptor pin insertion hole 16 extend in the vertical direction so as to penetrate the cooling plate 10, respectively, and allow the separation pins (separation means) 30 to pass through the inside of the separation pin insertion hole 15. Meanwhile, the susceptor pins 31 are inserted into the respective susceptor pin insertion holes 16.
[0027]
The separation pins 30 have a small diameter with each of the distal ends having a pointed shape, each having a length sufficiently larger than the height of the cooling plate 10, and a horizontal pin connecting the individual base ends. The actuator is connected to an actuator such as a cylinder actuator (not shown) via the outer connection plate 32, and can be vertically moved in synchronization with each other by the operation of the actuator.
[0028]
The susceptor pin 31 has a small diameter with a pointed tip like the spacing pin 30 and has a length sufficiently larger than the height of the cooling plate 10 to connect the individual base ends. The actuator is connected to an actuator such as a cylinder actuator (not shown) via a horizontal inner connecting plate 33, and can be moved in the vertical direction in synchronization with each other by the operation of the actuator.
[0029]
On the other hand, the temperature control device includes a heating unit 40 on the upper surface of the cooling plate 10. The heating means 40 has a circular thin plate shape made of a material having high thermal conductivity, such as aluminum, similarly to the cooling plate 10 described above. Specifically, when the height of the cooling plate 10 is 30 to 40 mm, the heating means 40 is about 2 mm. A heat plate 41 having a plate thickness and thin film heaters 42 and 43 adhered and held on the front and back surfaces of the heat plate 41, respectively, are provided so as to penetrate through portions of the cooling plate 10 corresponding to the susceptor pin insertion holes 16 respectively. The cooling plate 10 has a hole 44, and the through hole 44 is mounted on the upper surface of the cooling plate 10 so as to match the susceptor pin insertion hole 16 and cover the separation pin insertion hole 15.
[0030]
Although not shown in the drawing, the thin film heaters 42 and 43 are formed by appropriately forming a resistance wire inside a resin having heat stress resistance such as a polyimide resin or the like. And has a thin-film disk shape having a diameter larger than the wafer W to be processed, and is bonded to the heat plate 41 by bonding means such as a welding sheet. In addition, a shim 45 for securing a gap of about 0.1 mm between the thin film heater 42 and the wafer W attached to the upper surface of the heat plate 41 is provided.
[0031]
Hereinafter, in the temperature control device configured as described above, the operation when the temperature of the wafer W is alternately controlled at 150 ° C. and 20 ° C. at intervals of several tens of seconds, that is, the temperature of the wafer W is set to 150 ° C. The operation in the case where the baking to be performed and the cooling for subsequently cooling the temperature of the wafer W to 20 ° C. are alternately performed will be described.
[0032]
First, in the temperature control device, when in a start-up standby state, each end of the above-described separation pin 30 is disposed inside the separation pin insertion hole 15, and the heating unit 40 is mounted on the upper surface of the cooling plate 10. In addition, each end of the above-described susceptor pin 31 is disposed inside the susceptor pin insertion hole 16.
[0033]
When the wafer W coated with the resist is loaded into the chamber C while being placed on the robot hand R from the start standby state described above, the susceptor pins 31 synchronously move upward as shown in FIG. The wafer W placed on the robot hand R is received between the tips of the susceptor pins 31.
[0034]
During this time, in the temperature control device, the separation pin 30 moves upward in synchronization, and the heating means 40 is separated from the upper surface of the cooling plate 10, specifically, about 20 mm. By operating the thin film heaters 42 and 43, the heating means 40 is maintained at a temperature of about 150 ° C., and the supply pump 22 is operated to circulate and supply the temperature fluid L stored in the heat storage tank 21. As a result, the cooling plate 10 is maintained at a temperature near 20 ° C.
[0035]
Here, in the above-described state, although the heating unit 40 in the high temperature state and the cooling plate 10 in the low temperature state are arranged to face each other, most of the heat radiation from the heating unit 40 is directed upward. On the other hand, since most of the cold heat radiation from the cooling plate 10 proceeds downward, the thermal contact is also disconnected, and there is no possibility that both will thermally affect each other.
[0036]
Moreover, in the heating means 40, since the thin film heaters 42 and 43 adhered to the front and back surfaces of the heat plate 41 operate, there is no possibility that a temperature difference occurs between the front side portion and the back side portion. The situation where the heat plate 41 is deformed toward the out-of-plane direction does not occur.
[0037]
Therefore, after the robot hand R has evacuated, as shown in FIG. 3A, the susceptor pin 31 is synchronously moved down while the separation pin 30 is moved upward, and the wafer W is heated via the shim 45. When the wafer W is placed on the upper surface of the heating means 40, the wafer W can be quickly and accurately heated to 150 ° C. with a uniform gap secured between the wafer W and the heating means 40.
[0038]
When the baking performed by heating the wafer W to 150 ° C. by the operation described above is completed, cooling for cooling the temperature of the wafer W to 20 ° C. is performed.
[0039]
That is, when the baking is completed, the operations of the thin film heaters 42 and 43 are immediately stopped, and thereafter, the separation pins 30 move down in synchronization with each other, and the heating means 40 is mounted on the upper surface of the cooling plate 10.
[0040]
At that time, at the initial stage when the heating means 40 reaches the upper surface of the cooling plate 10, as shown in FIG. 3 (b), the back side portion of the heat plate 41 is in a lower temperature state than its front side portion. The heat plate 41 is deformed upward in an out-of-plane direction.
[0041]
However, in the state shown in FIG. 3B described above, the outer peripheral portion of the heat plate 41 which comes into contact with the cooling plate 10 and is in a lower temperature state is separated from the wafer W, while being separated from the cooling plate 10 and the outer peripheral portion The central portion of the heat plate 41 in which the temperature is higher than that is close to the wafer W, and the variation in the temperature distribution with respect to the wafer W is offset by the relationship of these distances, and the temperature distribution of the wafer W There is no possibility of influence due to variation.
[0042]
As the cooling by the cooling plate 10 progresses, the temperature difference between the front side portion and the back side portion of the heat plate 41 is eventually eliminated, and as shown in FIG. The heat of the wafer W is uniformly radiated via the cooling plate 41 and the cooling plate 10, and the wafer W is rapidly and accurately cooled to 20 ° C.
[0043]
When the cooling of the wafer W is completed as described above, the susceptor pins 31 move upward in synchronization with each other, so that the wafer W is spaced apart from the heating means 40. Is replaced with a new wafer W, and the same heating and cooling are repeatedly performed on the new wafer W.
[0044]
As described above, according to the temperature control device, when the thin film heaters 42 and 43 are operated, the heat plate 41 and the cooling plate 10 are separated from each other by the separation pin 30, and the thermal contact therebetween is cut off. Therefore, it is possible to prevent a situation in which the heat of the heating means 40 is released via the cooling plate 10 and a situation in which the heat plate 41 is deformed in an out-of-plane direction, and the wafer W can be quickly and accurately moved. Can be heated.
[0045]
In addition, even while the thin film heaters 42 and 43 are operated, the supply pump 22 can be continuously operated to cool the cooling plate 10 without causing energy loss. W can be cooled quickly and accurately.
[0046]
Further, according to the temperature control device, the heating step and the cooling step of the wafer W can be performed on the same upper surface of the heat plate 41, so that not only the space can be saved, but also the work efficiency can be improved. But it is very advantageous.
[0047]
In the above-described embodiment, an example in which the temperature of the wafer is controlled in the semiconductor manufacturing process is described. However, the present invention can be applied to the case where the temperature of another object to be controlled is controlled.
[0048]
Further, in the above-described embodiment, since the heating means employs a heat plate in which thin film heaters are adhered to both the front and back surfaces of the heat plate, deformation of the heat plate in the out-of-plane direction can be more reliably prevented. Although possible, the present invention is not limited to this. For example, the heating means may be configured by incorporating a heater in the heat plate, or a plate-shaped heater may be applied as the heating means, and the plate-shaped heater may be used as the heat plate. Further, as in the case of cooling, the heating means may be formed by forming the heat plate in a hollow shape and supplying a high-temperature fluid to the hollow portion.
[0049]
Further, in the above-described embodiment, when the heat plate and the cooling plate are spaced apart from each other, the heat plate is moved with respect to the fixed cooling plate, but the cooling plate is moved with respect to the heat plate. Alternatively, both may be moved at the same time. Further, as the separating means, a separating pin which moves vertically in a manner penetrating the cooling plate is applied, and the heat plate is moved to an area above the cooling plate. It is possible to reduce the size of the device by securing a space, but the present invention is not limited to this. For example, a fixed arm may be provided on the heat plate, and the heat plate and the cooling plate may be separated from each other by operating the fixed arm. In this case, the direction of movement of the heat plate does not necessarily have to be in the upper region of the cooling plate, but may be moved to the side region or lower region of the cooling plate. When the fixing arm is provided on the heat plate, it is needless to say that a heat insulating material is preferably interposed between the heat plate and the heat plate.
[0050]
Furthermore, in the above-described embodiment, as the cooling means, a means for supplying a temperature fluid into the closed hollow portion of the cooling plate is illustrated. However, a chamber that is open to the atmosphere is formed in the cooling plate, and the temperature fluid is supplied to the chamber. The same operation and effect can be expected even if the cooling means is formed by spraying or directly arranging the heat transfer element of the cooling plate.
[Brief description of the drawings]
FIG. 1 is a diagram conceptually showing an embodiment of a temperature control device according to the present invention.
FIG. 2 is an exploded perspective view of a main part of the temperature control device shown in FIG.
FIG. 3 is a view sequentially showing the operation of the temperature control device shown in FIG. 1;
[Explanation of symbols]
Reference Signs List 10 cooling plate, 20 discharge passage, 21 heat storage tank, 22 supply pump, 23 supply passage, 30 separation pin, 40 heating means, 41 heat plate, 42, 43 thin film heater, L temperature fluid , W ... wafer.

Claims (4)

A heat plate, which is mounted on a base and constitutes a heating means for adjusting and maintaining a temperature-controlled object placed on the upper surface at a preset high temperature state, and cooling the base, A cooling means for adjusting and maintaining the temperature-controlled object at a preset low-temperature state via a plate,
A temperature control device, further comprising: a separation unit that separates the heat plate and the base from each other when operating the heating unit. 2. The temperature control device according to claim 1, wherein the heater is configured by disposing heaters on both upper and lower surfaces of the heat plate. The separating means is arranged so as to be vertically movable in a manner penetrating the base, and moves the heat plate upward with respect to the base when operating the heating means. The temperature control device according to claim 1, wherein By operating the heating means configured on the heat plate, the temperature-controlled object placed on the upper surface of the heat plate is adjusted and maintained at a preset high temperature state, while the base on which the heat plate is mounted is mounted. By cooling, the temperature control method for adjusting and maintaining the temperature-controlled object to a preset low temperature state through the heat plate,
A temperature control method, wherein the heat plate and the base are separated from each other when the heating means is operated.

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