JP2008117956A - Substrate cooling apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate cooling apparatus wherein any sensor for sensing the temperature of a substrate, any timing signal fed from host control systems, and so forth are made unneeded, and even for a high-speed-cool-able substrate cooling apparatus having a reduced gap, its cooling time can be shortened independently of the temperature of the substrate mounted on it. <P>SOLUTION: A temperature controlling portion of the substrate cooling apparatus has a temperature controlling function wherein a controlling program for temperature-controlling a substrate mounting plate in response to a target setting temperature T0 is provided, and has a target-temperature altering function for altering the target setting temperature T0 of the target value of the temperature control to a higher first temporarily set temperature T1 when a temperature varying factor dT of the substrate mounting plate exceeds a first decision value dT1. After a predetermined returning time tL elapses from the time point whereat the set target setting temperature T0 is altered to the first temporarily set temperature T1, its temperature is so controlled that the originally set target setting temperature T0 returns. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a substrate cooling apparatus used in a lithography process of a substrate such as a semiconductor wafer.

  Conventionally, in a lithography process of a substrate such as a semiconductor wafer, there has been a substrate cooling device for controlling cooling of a substrate heated to a high temperature before and after a photoresist solution coating and developing process to a target temperature near room temperature. 11, the substrate mounting plate 2 having minute protrusions 2 a for supporting the substrate 1 in a mounting state with a slight gap S, and the lower surface side of the substrate mounting plate 2 are in contact with each other. And a plurality of thermoelectric modules 3 that are dispersedly arranged at appropriate intervals, and water-cooling that is a water-cooled heat exchanger as a cooling body arranged in contact with the lower surface side of each thermoelectric module 3 The structure was provided with a jacket 4.

  Providing such a gap S between the substrate 1 and the substrate mounting plate 2 prevents dust from adhering to the lower surface of the substrate 1 or causes large temperature unevenness in the substrate 1 surface. This is to prevent this.

  The substrate mounting plate 2 is provided with a plate temperature sensor 5 for detecting the temperature of the substrate mounting plate 2, and the water cooling jacket 4 is supplied with a coolant for supplying and discharging cooling water as a refrigerant. The supply port 4a and the discharge port 4b were provided.

  When the substrate 1 such as a high-temperature semiconductor wafer is placed and supported on the protrusion 2a of the substrate placement plate 2 of the substrate cooling device 6 having such a structure, the heat of the substrate 1 is supported on the substrate placement plate 2. The electric current supplied to each thermoelectric module 3 is controlled by PID control or the like according to the temperature detected by the plate temperature sensor 5 disposed on the substrate mounting plate 2, and the substrate mounting plate 2 is Heat is absorbed by the thermoelectric module 3, and the heat radiating surface of each thermoelectric module 3 is cooled by the water cooling jacket 4. Here, the temperature of the substrate mounting plate 2 is set to a desired target temperature by the control of each thermoelectric module 3 by the temperature controller. The structure is configured to cool and indirectly cool and control the temperature of the substrate 1 such as a semiconductor wafer to a desired target temperature. Here, the thermoelectric module 3 and the water cooling jacket 4 constitute a cooling means.

  In cooling the substrate 1 such as a semiconductor wafer, a substrate cooling apparatus employing various cooling control methods has been proposed in order to efficiently use the thermoelectric module 3 composed of thermoelectric elements and to shorten the cooling time as much as possible. (For example, see Patent Documents 1 to 5).

  That is, according to Patent Document 1, cooling is performed with the maximum cooling output from the time when the substrate is obtained by a signal from the substrate transport unit, or the cooling plate is set with the second set temperature lower than the normal set temperature as a target. The temperature is controlled, and when the second set temperature is reached, the temperature of the cooling plate is controlled at the normal set temperature.

  According to Patent Document 2 and Patent Document 3, a boundary temperature higher than the normal set temperature is set, and when the plate temperature becomes higher than the boundary temperature, cooling is performed at the maximum cooling output, and the plate temperature becomes lower than the boundary temperature. Alternatively, when a predetermined time elapses from when the temperature becomes low, the temperature of the cooling plate is controlled at a normal set temperature.

  Further, according to Patent Document 4, as in Patent Document 1, cooling is performed at the maximum cooling output from the time of placing the substrate, the temperature rising peak of the cooling plate is detected, and the normal temperature associated with the obtained temperature rising peak is The cooling plate is temperature-controlled at a second set temperature lower than the set temperature, and when the plate temperature reaches the second set temperature, the cooling plate is temperature-controlled at the normal set temperature.

  According to Patent Document 5, when the wafer temperature obtained by the wafer temperature measurement sensor is separated from the cooling target set temperature of the cooling plate, cooling is performed with the maximum cooling output, and the temperature difference between the two is below a predetermined difference. If it becomes, it is set as the method switched to PID control.

JP-A-8-273993 JP-A-8-236414 JP-A-7-121247 JP-A-8-203796 JP-A-7-121246

  However, there is a limit to shortening the cooling time by the method of controlling the cooling output of the thermoelectric module 3. This is because heat transfer through the air layer due to the gap S between the substrate 1 and the substrate mounting plate 2 has a greater influence on the cooling time.

  Therefore, by reducing the gap S between the placed substrate 1 and the substrate placing plate 2, a substrate cooling device capable of high-speed cooling can be obtained. For example, conventionally, the distance of the gap S between the substrate 1 and the substrate mounting plate 2 was about 100 μm, but by shortening the gap S to 60 μm or less, the heat of the substrate 1 can be quickly increased. Can tell.

  However, when such a conventional control method is employed in such a substrate cooling apparatus, the following problems occur.

  That is, in the substrate cooling apparatus having a small gap S, the temperature of the substrate 1 rapidly approaches the temperature of the substrate mounting plate 2. For this reason, even if the maximum output cooling is started from the placement time of the substrate 1, the temperature of the substrate 1 becomes the temperature of the substrate placement plate 2 until the substrate placement plate 2 reaches the set target temperature. To reach. Therefore, when the substrate mounting plate 2 is cooled to a predetermined temperature that is equal to or lower than the target temperature, the substrate 1 is also cooled to the target temperature or lower, as shown in FIG. Become. For this reason, in the substrate cooling apparatus in which the gap S is reduced, a control method for cooling the temperature of the substrate mounting plate 2 to be lower than the target temperature cannot be adopted.

  Further, the temperature of the substrate 1 placed on the substrate placement plate 2 varies depending on the type of processing of the substrate 1 and the waiting time from the end of heating to the placement on the substrate cooling device, and is always the same. Not exclusively.

  On the other hand, in the case of a conventional substrate cooling device having a normal gap S, it takes time until the temperature of the substrate 1 approaches the temperature of the substrate mounting plate 2, so that the temperature of the substrate mounting plate 2 is stable. There was time to do so, and the influence due to the temperature difference of the substrate 1 could be absorbed.

  However, in the high-speed cooling type substrate cooling apparatus in which the gap S is reduced, the temperature of the substrate 1 approaches the temperature of the substrate mounting plate 2 in a short time, so that the temperature of the substrate mounting plate 2 is undershooted. It must be quickly converged to the target temperature.

  At this time, if the control conditions are optimized at the temperature of a certain substrate 1, there is a problem that when the substrate 1 at a different temperature is cooled, the temperature stability becomes slow and the cooling time becomes long.

  FIG. 13 shows a case where the substrate 1 heated to 200 ° C. is adjusted to control conditions suitable for cooling a semiconductor wafer as an example, and then the substrate 1 having a lower heating temperature is placed and cooled. The temperature change of the board | substrate 1 is shown. From this, it can be seen that when the temperature of the substrate 1 is low, undershoot occurs due to overcooling, and it takes a long time to stabilize the temperature.

  Further, in FIG. 14, after adjusting to control conditions suitable for cooling a semiconductor wafer as an example of the substrate 1 heated to 70 ° C., the substrate 1 having a higher heating temperature is placed and cooled. The temperature change of the board | substrate 1 in the case is shown. From this, it is understood that undershoot greatly occurs as the temperature of the substrate 1 to be placed increases.

  Further, in order to reduce the influence due to the temperature difference of the substrate 1, there is a method of controlling the temperature by determining the set temperature from the peak temperature of the substrate mounting plate 2. In the substrate cooling apparatus having a small gap S between the targets, the target cooling time is short. Therefore, when the temperature of the substrate mounting plate 2 reaches the peak, the target cooling time is already close. Therefore, if it is determined whether or not the cooling is performed at the maximum cooling output at the peak temperature of the substrate mounting plate 2 or the set temperature is changed, the cooling time cannot be met. That is, such a conventional method cannot solve the problem of the influence due to the temperature difference of the substrate 1 with respect to the substrate cooling apparatus capable of high-speed cooling with a small gap S.

  Further, according to the method of directly detecting the temperature of the substrate 1 and switching the control method, it is necessary to separately install a sensor for detecting the temperature of the substrate 1 in the apparatus, which is disadvantageous in terms of cost and installation location. It is necessary to secure a wiring route.

  Furthermore, according to the method of judging the timing when the substrate 1 is placed by an external signal, it is necessary to have the signal output from the control unit of the host device in the substrate processing step. On the other hand, in the upper apparatus, a plurality of substrates 1 are transported in a complicated procedure so that the number of processed substrates 1 is increased as much as possible. In such a situation, outputting the timing when the substrate 1 is placed (so-called cooling start) is a heavy burden for the control of the host device. Therefore, if possible, it is desirable that the substrate 1 is always optimally cooled only by placing the substrate 1 without outputting a signal of such timing.

  Therefore, the problem to be solved by the present invention is that even a substrate cooling device capable of high-speed cooling with a reduced gap does not require a sensor for detecting the temperature of the substrate or a timing signal from the host control system. An object of the present invention is to provide a substrate cooling apparatus capable of shortening the cooling time regardless of the temperature of the substrate to be placed.

  Technical means for solving the above problems include a substrate placement plate that supports a substrate in a placement state with a slight gap, and temperature control of the substrate placement plate in accordance with a detected temperature of the substrate placement plate. And a cooling means for controlling the temperature of the substrate mounting plate in accordance with a control signal from the temperature control unit, wherein the temperature control unit is configured to cool the substrate to a target temperature. A temperature control function having a control program for controlling the temperature of the substrate mounting plate according to the target temperature, and a target that is a target value for temperature control when the temperature change rate of the substrate mounting plate exceeds a predetermined determination value A target temperature changing function for changing the temperature to a higher temporary target temperature, and when the set target temperature is changed to the temporary target temperature, the original target temperature is restored after a predetermined return time has elapsed. It lies in controlling the temperature and.

  Further, a plurality of the predetermined determination values in the temperature change rate are set stepwise, and a target temperature that is a target value for the temperature control every time the temperature change rate of the substrate mounting plate exceeds a predetermined determination value. May be gradually changed to a higher temporary target temperature.

  Further, when the determination value of the highest value in the temperature change rate is exceeded, the cooling output by the cooling means is maximized, and the set target temperature is set after a predetermined maximum output continuation time when the cooling output is maximum. The control may be changed to a higher temporary target temperature.

  In addition, when the determination value of the highest value in the temperature change rate is exceeded, the cooling output by the cooling unit is maximized, and the set value is set after the detected temperature of the substrate mounting plate becomes equal to or lower than a predetermined temperature. The control may be changed to a temporary target temperature higher than the target temperature.

  Further, when the temperature of the substrate mounting plate exceeds a predetermined determination value, the temperature change rate detected after elapse of a predetermined time from exceeding the determination value exceeds the predetermined determination value. The control may be performed by selecting and changing a plurality of temporary target temperatures higher than the set target temperature, or performing cooling with the maximum cooling output by the cooling means.

  According to the substrate cooling apparatus of the present invention, the temperature control unit has a temperature control function including a control program for controlling the temperature of the substrate mounting plate according to the target temperature, and the temperature change rate of the substrate mounting plate is determined as a predetermined value. A target temperature change function that changes the target temperature, which is the target value for temperature control, to a higher temporary target temperature when the value exceeds the value, from the time when the set target temperature is changed to the temporary target temperature. This is a control method in which the temperature is controlled by returning to the original set target temperature after a predetermined return time has elapsed, and even if a substrate with a different heating temperature is mounted, the temperature change rate of the substrate mounting plate is determined in a predetermined manner. When the value exceeds the target temperature, the target temperature, which is the target value of the temperature control, is changed to the temporary target temperature to control the temperature of the substrate mounting plate. Temperature control is possible and cooling And it is effectively prevented undershoot in, there is effectively an advantage that good attained shorten the cooling time.

  In addition, since the temperature of the substrate mounting plate is controlled by changing the target temperature, which is the target value of the temperature control, to a higher temporary target temperature, the substrate cooling device can cool the substrate even if the substrate cooling device has a reduced gap. There is an advantage that undershoot at the time can be effectively prevented, the cooling capacity of the apparatus can be efficiently exhibited, and the cooling time can be shortened.

  Therefore, a separate sensor for detecting the temperature of the substrate, the transmission of a cooling start signal from the host control system, substrate temperature information, and the like are not required.

  In addition, a plurality of the predetermined determination values in the temperature change rate are set stepwise, and the target temperature, which is the target value for temperature control, is higher each time the temperature change rate of the substrate mounting plate exceeds the predetermined determination value. If the control method gradually changes to the tentative target temperature, even a substrate cooling device with a reduced gap can more effectively prevent undershoot during substrate cooling, and the cooling capacity in a device capable of high-speed cooling This is advantageous in that the cooling time can be further shortened.

  Furthermore, when the determination value of the highest value in the temperature change rate is exceeded, the cooling output by the cooling means is maximized, and the cooling output is higher than the set target temperature after the maximum predetermined maximum output duration has elapsed. If the control method is changed to the tentative target temperature, the maximum cooling output can be effectively used for more efficient cooling, and from this point, the cooling time can be further shortened.

  In addition, when the determination value of the highest value in the rate of temperature change is exceeded, the cooling output by the cooling means is maximized, and after the detected temperature of the substrate mounting plate falls below a predetermined temperature, the set target temperature is exceeded. If the control method is changed to a higher tentative target temperature, the maximum cooling output can be effectively used for more efficient cooling, and from this point, the cooling time can be further shortened.

  Further, when the temperature of the substrate mounting plate exceeds a predetermined determination value, the temperature change rate detected after elapse of a predetermined time after the determination value is exceeded exceeds a predetermined determination value. By selecting and changing from a plurality of provisional target temperatures higher than the target temperature, or by using a control method that performs cooling with the maximum cooling output by the cooling means, suitable temperature control can be performed according to the temperature change rate, and efficient Cooling can be performed, and from this point, there is an advantage that the cooling time can be shortened effectively.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Similarly to the substrate cooling apparatus 6 shown in FIG. 11, a substrate 1 such as a semiconductor wafer is placed in a mounted state having a slight gap S by a projection 2a or the like. As a substrate placed plate 2 to be supported, a plurality of thermoelectric modules 3 dispersedly arranged in contact with the lower surface side of the substrate placed plate 2, and a cooling body arranged in contact with the lower surface of each thermoelectric module 3 It is set as the structure provided with the water cooling jacket 4 which is this water cooling type heat exchanger. In this embodiment, the substrate cooling device 6 is capable of high-speed cooling with the gap S being reduced compared to the conventional case, for example, with the gap S being 60 μm or less.

  The water-cooling jacket 4 includes a jacket main body formed in a circular block shape in plan view formed of aluminum, an aluminum alloy, or the like, and includes a refrigerant feeding pipe disposed in a meandering manner in the jacket main body. Cooling water as a refrigerant is supplied from a supply port 4a which is one end of the refrigerant supply pipe, and is discharged from a discharge port 4b which is the other end. The water cooling jacket 4 has a circular shape that is slightly larger than the substrate 1 to be cooled.

  The thermoelectric modules 3 are distributed and arranged at predetermined positions on the upper surface of the jacket main body of the water cooling jacket 4 at appropriate intervals. The thermoelectric modules 3 and the water cooling jacket 4 constitute cooling means.

  Further, a substrate mounting plate 2 made of aluminum, an aluminum alloy or the like is disposed across the upper surface of each thermoelectric module 3, and the substrate mounting plate 2 is circular in plan view like the jacket body of the water cooling jacket 4. It is formed in a block shape with the same diameter as the jacket body.

  The substrate mounting plate 2 and the water cooling jacket 4 are overlapped with each other at an appropriate position avoiding each thermoelectric module 3 in a state where the substrate mounting plate 2 and the jacket main body of the water cooling jacket 4 overlap each other in plan view. By this screw fastening, each thermoelectric module 3 is connected and fixed in a state of being sandwiched between the opposing surfaces of the substrate mounting plate 2 and the water cooling jacket 4.

  In addition, each thermoelectric module 3 is connected to a control device (not shown), the contact surface on the water cooling jacket 4 side of each thermoelectric module 3 is a heat dissipation surface, and the contact surface on the substrate mounting plate 2 side is a heat absorption surface. It is configured to function.

  The substrate mounting plate 2 is equipped with a plate temperature sensor 5 for detecting the temperature as in the prior art. As shown in FIG. 2, the detected temperature detected by the plate temperature sensor 5 is a detection signal. It is comprised so that it may input into the temperature control part 8 of a control apparatus.

  Then, the temperature control unit 8 outputs a control signal to the cooling drive unit 9 in accordance with the detected temperature detected by the plate temperature sensor 5, and the cooling drive unit 9 performs cooling or heating in accordance with the input control signal. Is supplied to each thermoelectric module 3 for supply.

  In addition, the temperature control unit 8 includes, for example, a temperature control function including a program for PID control as a control program for controlling the temperature of the substrate mounting plate 2 according to the target temperature, and a temperature change of the substrate mounting plate 2. It has a target temperature change function that changes the target temperature, which is the target value for temperature control, to a higher temporary target temperature when the rate exceeds a predetermined judgment value. A set value such as a target temperature, a temporary target temperature, a temperature change rate determination value, or the like can be input and changed as desired from the value input unit 10.

  In the present embodiment, as shown in FIG. 3, a target set temperature T0 is set as a target temperature for cooling the substrate 1. Further, as the predetermined determination value in the temperature change rate, a plurality of first determination value dT1, second determination value dT2, and the highest third determination value dTN are set in stages. Then, the first temporary set temperature T1 is set as a higher temporary target temperature when the first determination value dT1 is exceeded, and the second temporary target temperature is set as a higher temporary target temperature when the second determination value dT2 is exceeded. Temporary set temperature T2 is set.

  Further, when the temperature change rate exceeds the third determination value dTN, control is performed so that the cooling output by each thermoelectric module 3 becomes maximum, and the state where the cooling output is maximum continues for a predetermined time. Is done. The maximum output duration tmax is set as the predetermined time, and after the maximum output duration tmax has elapsed, control is performed to change the temporary target temperature to be higher than the target set temperature T0. A third temporary set temperature TN is set as the temperature.

  Furthermore, when a predetermined fixed time elapses from the first change of the target temperature, the temperature is controlled to return to the original target temperature, and the predetermined time is longer than the maximum output duration tmax. A return time tL is set. Accordingly, when the set target set temperature T0 is changed to the first temporary set temperature T1, regardless of the subsequent change in the target temperature, after the return time tL has elapsed since the change to the first temporary set temperature T1. The control method is such that the temperature is controlled by returning to the original target set temperature T0.

  Next, cooling control by the substrate cooling device 6 will be described based on the flowchart shown in FIG.

  As shown in FIG. 3, first, PID control is performed so that the substrate mounting plate 2 reaches the target set temperature T0 until the substrate 1 such as a semiconductor wafer is mounted on the substrate mounting plate 2 (see FIG. 3). Step S1). In addition, this step S1 is not necessarily an operation | work required, but the method of controlling temperature other than target setting temperature T0 may be sufficient.

  Thereafter, when the substrate 1 heated to a high temperature is placed on the substrate placement plate 2, the temperature of the substrate placement plate 2 rises due to heat conduction from the substrate 1. The temperature controller 8 always detects the temperature of the substrate mounting plate 2 via the plate temperature sensor 5 and measures the temperature change rate dT. Whether the temperature change rate dT exceeds the first determination value dT1. Whether or not is determined (step S2).

  When the temperature change rate dT exceeds the first determination value dT1 due to an increase in the temperature change rate dT of the substrate mounting plate 2, the temperature change rate is changed from the target set temperature T0 as the target temperature, which is the target value for temperature control. The temperature is changed to the first temporary set temperature T1, which is a higher target temperature associated with dT, and thereafter, PID control is performed so that the first temporary set temperature T1 is reached. Simultaneously with the setting change of the target temperature, the first timer t1 for measuring the return time tL is set to 0, and the elapsed time t is started to be measured by the first timer t1 (step S3).

  Thereafter, it is determined whether or not the elapsed time t by the first timer t1 has passed the return time tL (step S4). If the return time tL has passed, the process returns to step S1. In step S4, if the return time tL has not elapsed, it is determined whether the temperature change rate dT exceeds the second determination value dT2 (step S5).

  When the temperature change rate dT exceeds the second determination value dT2, the second temporary value that is a higher target temperature associated with the temperature change rate dT from the first temporary set temperature T1 that is the current target temperature control temperature. The temperature is changed to the set temperature T2 (step S6), and thereafter, PID control is performed so that the second temporary set temperature T2 is reached.

  Thereafter, it is determined whether or not the elapsed time t by the first timer t1 has passed the return time tL (step S7). If the return time tL has passed, the process returns to step S1. In step S7, if the return time tL has not elapsed, it is determined whether the temperature change rate dT exceeds the third determination value dTN, which is the final determination value (step S8).

  When the temperature change rate dT exceeds the third determination value dTN, the cooling output is maximized and the maximum output duration tmax is measured regardless of the second temporarily set temperature T2 which is the current temperature control target temperature. The second timer t2 is set to 0, and the elapsed time t is started to be measured by the second timer t2 (step S9).

  Thereafter, it is determined whether or not the elapsed time t by the first timer t1 has passed the return time tL (step S10). If the return time tL has passed, the process returns to step S1. In step S10, if the return time tL has not elapsed, it is determined whether the elapsed time t by the second timer t2 has not exceeded the maximum output duration tmax (step S11), and the maximum output duration tmax. If not, the process returns to step S10. In step S11, if the maximum output duration time tmax has elapsed, the target temperature for temperature control is changed to a third temporary set temperature TN that is higher than the target set temperature T0, which is a normal target temperature, and thereafter the third temporary set temperature TN. PID control is performed so that the set temperature TN is reached (step S12). In addition, even if it transfers to this PID control, when a cooling output becomes the maximum as a result of the calculation, cooling will be continued with the maximum cooling output.

  Thereafter, it is determined whether or not the elapsed time t by the first timer t1 has passed the return time tL (step S13). If the return time tL has passed, the process returns to step S1. In step S13, when the elapsed time t by the first timer t1 has not passed the return time tL, the detected temperature difference between the substrate placement plate 2 and the third temporary set temperature TN is a predetermined value. If the value is lower than the value, the current set temperature may be returned to the target set temperature T0, and the temperature of the substrate mounting plate 2 may be PID controlled.

  When the temperature of the substrate mounting plate 2 is stabilized at the target set temperature T0, it is determined that the substrate 1 has been cooled to the target set temperature T0, and is taken out from the substrate mounting plate 2 and the next substrate 1 is mounted. And the same temperature control is repeated.

  FIG. 4 shows a relationship diagram between the cooling output, the temperature of the substrate mounting plate 2 and the temperature of the semiconductor wafer in the cooling control when the temperature of the semiconductor wafer as an example of the substrate 1 is low. In this case, since the temperature change rate dT does not reach the first determination value dT1, the target set temperature T0 is not changed and is cooled within the target time by the same control as usual.

  FIG. 5 shows the relationship between the cooling output, the temperature of the substrate mounting plate 2 and the temperature of the semiconductor wafer in the cooling control when the temperature of the semiconductor wafer is high. In this case, when a semiconductor wafer is mounted on the substrate mounting plate 2, the temperature change rate dT of the substrate mounting plate 2 exceeds the first determination value dT1, and the target set temperature T0 is higher than normal. The temperature is changed to the temporarily set temperature T1. As a result, the temperature of the semiconductor wafer is quickly cooled without greatly undershooting.

  FIG. 6 shows a relationship diagram between the cooling output, the temperature of the substrate mounting plate 2 and the temperature of the semiconductor wafer in the cooling control when the temperature of the semiconductor wafer is higher. In this case, when the semiconductor wafer is mounted on the substrate mounting plate 2, the temperature change rate dT of the substrate mounting plate 2 exceeds the first determination value dT1, and further exceeds the second determination value dT2. The target set temperature T0 is changed to the first temporary set temperature T1, and further to the higher second temporary set temperature T2. As a result, the temperature of the semiconductor wafer is quickly cooled without greatly undershooting.

  FIG. 7 shows a relationship diagram between the cooling output, the temperature of the substrate mounting plate 2 and the temperature of the semiconductor wafer in the cooling control when the temperature of the semiconductor wafer is even higher. In this case, when the semiconductor wafer is mounted on the substrate mounting plate 2, the temperature change rate dT of the substrate mounting plate 2 exceeds the first determination value dT1, further exceeds the second determination value dT2, Exceeds the third determination value dTN, so that the cooling output is cooled at the maximum. Thereafter, when the maximum output continuation time tmax elapses, the temperature is controlled at the third temporary set temperature TN, and when the return time tL elapses after changing the set temperature for the first time, the temperature is controlled at the target set temperature T0 that is a normal set temperature. The

  In this way, since the cooling with the maximum cooling output is started at an early stage, the cooling of the semiconductor wafer is not delayed. On the other hand, when the temperature of the semiconductor wafer is low, the semiconductor wafer is not cooled at the maximum cooling output as described above, and the semiconductor wafer temperature can be effectively prevented from being disturbed during cooling. Suitable cooling control can be performed according to the above.

  FIG. 8 shows a test result when a semiconductor wafer as an example of the substrate 1 is cooled from each heating temperature using the substrate cooling device 6 in the present embodiment.

  At this time, the target set temperature T0, which is the target temperature, is 23 ° C., the first determination value dT 1 is 0.6 ° C./second, the first temporary set temperature T 1 is the target set temperature T 0 + 0.15 ° C., and the second determination value dT 2. Is 1.0 ° C./second, the second temporary set temperature T2 is the target set temperature T0 + 0.25 ° C., the third determination value dTN that maximizes the cooling output is 1.2 ° C./second, and the maximum output duration tmax is 3. Second, the third temporary set temperature TN after the maximum cooling output is the target set temperature T0 + 0.15 ° C., and the return time tL for returning to the target set temperature T0 is 25 seconds.

  As shown in FIGS. 13 and 14, in the conventional control method, the cooling characteristics differ depending on the heating temperature of the semiconductor wafer. However, in the control method of this embodiment, as shown in FIG. It can be seen that even if the heating temperatures are different, each temperature converges to the target temperature without being disturbed.

  In the conventional substrate cooling apparatus 6 in which the gap S is 100 μm, when a semiconductor wafer having a heating temperature of 200 ° C. is cooled to 23 ° C. by PID control, the cooling time takes about 40 seconds. In the substrate cooling apparatus 6 of this embodiment having a thickness of 60 μm, when a semiconductor wafer having a heating temperature of 200 ° C. is cooled to 23 ° C., the cooling time is approximately 20 seconds, and the cooling time is reduced to almost half compared to the conventional case. Therefore, the effect of reducing the gap S can be sufficiently exhibited.

  As described above, according to the present embodiment, even if the substrate 1 having a different heating temperature is placed on the substrate placing plate 2, the temperature change rate dT of the substrate placing plate 2 is the predetermined determination value dT1 (dT2). ), The target set temperature T0 (first temporary set temperature T1), which is the target value for temperature control, is changed to a higher temporary set temperature T1 (T2) to control the temperature of the substrate mounting plate 2. The temperature of the substrate mounting plate 2 can be controlled in accordance with the temperature of the mounted substrate 1, and undershooting during cooling can be effectively prevented, and the cooling time can be shortened efficiently.

  In addition, since the target setting temperature T0 (first temporary setting temperature T1), which is a target value for temperature control, is changed to a higher temporary setting temperature T1 (T2), the temperature of the substrate mounting plate 2 is controlled. Even in the substrate cooling device 6 with reduced S, there is an advantage that undershooting during the cooling of the substrate 1 can be effectively prevented, the cooling capacity in the device 6 can be efficiently exhibited, and the cooling time can be shortened.

  Therefore, there is an advantage that a separate sensor for detecting the temperature of the substrate 1, a cooling start signal from the host control system, transmission of substrate temperature information, and the like are unnecessary.

  Further, a plurality of predetermined determination values dT1 and dT2 at the temperature change rate dT are set in stages, and each time the temperature change rate dT of the substrate mounting plate 2 exceeds the predetermined determination values dT1 and dT2, the target of temperature control This is a control method in which the target set temperatures T0 and T1 as values are gradually changed to higher temporary set temperatures T1 and T2, and even when the substrate cooling device 6 has a reduced gap S, it is under-cooled when the substrate 1 is cooled. The chute can be more effectively prevented, the cooling capacity of the apparatus 6 capable of high-speed cooling can be exhibited more efficiently, and the cooling time can be further shortened.

  Further, when the third determination value dTN as the determination value of the highest value in the temperature change rate dT is exceeded, the cooling output by each thermoelectric module 3 is maximized, and a predetermined maximum output duration tmax at the maximum cooling output. This is a control method of changing to the third temporary set temperature TN higher than the target set temperature T0 after the elapse of time. The maximum cooling output in the substrate cooling device 6 can be effectively used to perform cooling more efficiently. There is an advantage that the time can be further shortened.

  In the above embodiment, the step of raising the target temperature according to the temperature change rate dT is two steps, but it may be one step or three or more steps, and may be determined as appropriate.

  In the above embodiment, an example is shown in which the target value of the control temperature is increased stepwise as the temperature change rate dT of the substrate mounting plate 2 increases. However, the temperature of the substrate mounting plate 2 is determined to be a predetermined value. The temperature change rate dT of the substrate mounting plate 2 is measured after a predetermined time has passed after exceeding the value, and according to the value, that is, according to which judgment values dT1 and dT2 set in advance are exceeded. Control that selects and changes from a plurality of provisional target temperatures higher than the normal set target set temperature T0, and performs cooling at the maximum cooling output by the cooling means if the measured value exceeds the determination value dTN It is good also as a method.

  In FIG. 9, the temperature change rate dTy is measured after a predetermined time tw from the time when the temperature of the substrate mounting plate 2 exceeds Tx, and cooling is performed by changing the set temperature or by the maximum cooling output depending on the value of the temperature change rate dTy. An example is shown.

  Also in this case, suitable temperature control can be performed according to the temperature change rate dT of the substrate mounting plate 2, and cooling can be performed efficiently as in the above-described embodiment, and shortening of the cooling time is also effective from this point of view. There are advantages that can be achieved.

  Further, after the temperature of the substrate mounting plate 2 exceeds a predetermined determination value, the temperature of the substrate mounting plate 2 is measured after a lapse of a predetermined time, and a normal set target set temperature T0 is determined according to the value. It is good also as a control method which selects and changes from several higher temporary target temperature, and performs cooling by the maximum cooling output by a cooling means, if the measured value exceeds predetermined value.

  FIG. 10 shows measurement of the temperature Ty of the substrate mounting plate 2 after a predetermined time tw from the time when the temperature of the substrate mounting plate 2 exceeds Tx, and cooling by changing the set temperature or the maximum cooling output depending on the value of the temperature Ty. An example of performing is shown. In this case, the change from the temperature Tx to the temperature Ty can be regarded as the temperature change rate dT for the predetermined time tw.

  Therefore, also in this case, suitable temperature control can be performed according to the temperature change rate dT of the substrate mounting plate 2, and cooling can be performed efficiently as in the above-described embodiment. There is an advantage that shortening can be effectively achieved.

  Note that, instead of the time when the temperature exceeds Tx, the time when the temperature change rate dT exceeds a predetermined value may be used as a reference.

  In the above embodiment, a method is described in which the maximum cooling output is continued for a predetermined maximum output duration tmax when the temperature change rate dT exceeds the third determination value dTN. After the determination value dTN of 3 is exceeded and the cooling output is maximized, if the detected temperature of the substrate mounting plate 2 falls below a predetermined temperature, the third temporary set temperature TN higher than the set target set temperature T0 In this case, the maximum cooling output can be effectively used for more efficient cooling, and from this point, the cooling time can be further shortened.

  Furthermore, in this embodiment, the structure which employ | adopted PID control as the control method which controls the temperature of the substrate mounting plate 2 is shown, However, The structure which employ | adopts the control program for other temperature control suitably may be sufficient. .

  The target set temperature T0, the first temporary set temperature T1, the second temporary set temperature T2, the first determination value dT1, the second determination value dT2, the third determination value dTN, the maximum output duration tmax, the return What is necessary is just to set time tL etc. suitably according to the cooling capacity etc. of the board | substrate cooling device 6. FIG.

It is a flowchart which shows the cooling control procedure of this invention. It is a schematic block diagram of a substrate cooling device. It is a relationship figure between the temperature of a substrate mounting plate, a temperature change rate, preset temperature, and cooling output. It is a relationship figure between the temperature of a substrate mounting plate and a semiconductor wafer, and cooling output. It is a relationship figure between the temperature of a substrate mounting plate and a semiconductor wafer, and cooling output. It is a relationship figure between the temperature of a substrate mounting plate and a semiconductor wafer, and cooling output. It is a relationship figure between the temperature of a substrate mounting plate and a semiconductor wafer, and cooling output. It is a temperature change figure at the time of the semiconductor wafer cooling by this board | substrate cooling device. It is a related figure of the temperature of a substrate mounting plate and temperature change rate in other embodiments. It is a related figure of temperature of substrate mounting plate and elapsed time in other embodiments. It is a schematic front view which shows the structure in a substrate cooling device. It is a related figure of the temperature of substrate mounting plate and a board | substrate at the time of employ | adopting the conventional temperature control method, and elapsed time. It is a temperature change figure at the time of board | substrate cooling at the time of employ | adopting the conventional temperature control method. It is a temperature change figure at the time of board | substrate cooling at the time of employ | adopting the conventional temperature control method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 Substrate mounting plate 3 Thermoelectric module 4 Water cooling jacket 5 Plate temperature sensor 6 Substrate cooling device

Claims (5)

A substrate mounting plate (2) for supporting the substrate (1) in a mounting state with a slight gap (S), and the substrate mounting plate (2) according to the detected temperature of the substrate mounting plate (2). A temperature control unit (8) for temperature control, and cooling means (3) (4) for controlling the temperature of the substrate mounting plate (2) according to a control signal from the temperature control unit (8), In the substrate cooling device (6) for cooling the substrate (1) to the target temperature (T0),
The temperature control unit (8) includes a temperature control function including a control program for controlling the temperature of the substrate mounting plate (2) according to the target temperature (T0), and the temperature change rate ( a target temperature changing function for changing a target temperature (T0), which is a target value for temperature control, to a higher temporary target temperature (T1) when dT) exceeds a predetermined determination value (dT1);
After the predetermined return time (tL) has elapsed from the time when the set target temperature (T0) is changed to the temporary target temperature (T1), the temperature is controlled to be returned to the original set target temperature (T0). A substrate cooling device. The substrate cooling apparatus according to claim 1,
A plurality of the predetermined determination values (dT1) and (dT2) in the temperature change rate (dT) are set stepwise, and the temperature change rate (dT) of the substrate mounting plate (2) is a predetermined determination value ( The target temperature (T0) (T1), which is the target value of the temperature control, is gradually changed to a higher temporary target temperature (T1) (T2) every time dT1) (dT2) is exceeded Cooling system. In the substrate cooling device according to claim 1 or 2,
When the determination value (dTN) of the highest value in the temperature change rate (dT) is exceeded, the cooling output by the cooling means (3) and (4) is maximized, and the cooling output is the maximum predetermined output. The substrate cooling apparatus is characterized by changing to a temporary target temperature (TN) higher than the set target temperature (T0) after elapse of time (tmax). In the substrate cooling device according to claim 1 or 2,
When the determination value (dTN) of the highest value in the temperature change rate (dT) is exceeded, the cooling output by the cooling means (3) (4) is maximized, and the detected temperature of the substrate mounting plate (2) After the temperature becomes equal to or lower than a predetermined temperature, the substrate cooling apparatus is changed to a temporary target temperature higher than the set target temperature (T0). The substrate cooling apparatus according to claim 3,
When the temperature of the substrate mounting plate (2) exceeds a predetermined determination value (Tx), the temperature change rate (dTy) detected after a predetermined time (tw) has passed since the determination value (Tx) was exceeded. Is selected from a plurality of provisional target temperatures higher than the set target temperature (T0) when the value exceeds the predetermined determination value (dT1) (dT2) (dTN), or the cooling means (3 The substrate cooling apparatus is characterized in that the cooling is performed with the maximum cooling output according to (4).

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