JP2002367914A - Heat treatment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat treatment device which can prevent the warp deformation of a workpiece from occurring on temperature rise of the workpiece, without causing the drop of throughput. SOLUTION: This heat treatment device is placed has a treatment container 14 capable of being vacuumized, a stage 24 on which the workpiece to be treated at a specified temperature provided within the treatment container, a heating means 50 having a plurality of zone heaters for heating the workpiece on the stage separately for each zone divided concentrically, and a power supply means 56 for supplying each zone heater of the heating means with power. Further, the device has a temperature measuring means 60 which is provided to correspond to at least one zone among the concentric zones, and a power control means 58 which controls the power supply means so that it may heat the workpiece to a warp safe temperature at least lower than the specified temperature, in condition that the workpiece bears such temperature distribution that the temperature at the center of the workpiece becomes high, and that the temperature of the periphery becomes lower, based on the detection value of the temperature measuring means at temperature rise of the workpiece. The power controller includes a limiter for limiting the quantity of operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat treatment apparatus for performing heat treatment such as film formation or annealing on a semiconductor wafer or the like one by one.

[0002]

2. Description of the Related Art Generally, in order to manufacture a semiconductor integrated circuit, a substrate such as a semiconductor wafer is repeatedly subjected to various heat treatments such as a film forming process, an etching process, an oxidative diffusion process, an annealing reforming process, and the like. An integrated circuit is formed. An example of a single-wafer heat treatment apparatus for performing such heat treatment will be described. FIG. 12 is a schematic configuration diagram showing an example of a conventional heat treatment apparatus, and FIG. 13 is a schematic diagram showing a warped state of a semiconductor wafer on a mounting table. This heat treatment apparatus has a processing container 2 which can be evacuated, and a mounting table 4 on which a semiconductor wafer W is mounted is provided therein, and a processing gas is supplied to a ceiling portion of the processing container 2. A shower head 6 for introduction is provided. And
A plurality of heating lamps 8 as heating means are provided below the bottom of the processing vessel 2, and the mounting table 4 is irradiated with heat rays radiated from the heating lamp 8 through a transmission window 10 made of, for example, quartz provided at the bottom. As a result, the temperature of the wafer W is increased and a desired heat treatment is performed at a predetermined temperature.

[0003]

In the process of processing semiconductor wafers, it is necessary to increase productivity, that is, throughput, so that the wafer temperature is raised to a predetermined process temperature as quickly as possible. I have. In this case, even if the temperature was rapidly increased, no serious problem occurred in the case of a wafer having a relatively small diameter, for example, a 6-inch wafer. However, as the wafer size increased to 8 inches and 12 inches, FIG. As shown in the figure, there has been a problem that the peripheral portion of the semiconductor wafer W itself warps upward and deforms when the temperature rises. The cause of the warpage is that the amount of thermal expansion on the back surface of the wafer in contact with the mounting table 4 is larger than that on the front surface of the wafer. Such a warping phenomenon of the wafer is particularly large in the case of a 12-inch (30 cm) wafer, and depending on the process temperature, the warping height H of the peripheral portion may reach up to about 3 mm. The reason why the wafer warps at the time of temperature rise is that the thermal expansion coefficient from room temperature to, for example, about 327 ° C. as shown in the graph of the thermal expansion coefficient of the Si wafer shown in FIG. Due to being much larger than that.

As described above, if warpage occurs, there is a problem that a transfer error occurs during transfer of the wafer, or if a thin film is deposited in this state, the film stress increases and the film is liable to peel off. . The present invention has been devised in view of the above problems and effectively solving them. SUMMARY OF THE INVENTION An object of the present invention is to provide a heat treatment apparatus capable of preventing the object from being warped and deformed when the temperature of the object is raised without lowering the throughput. This case is an improvement of the invention disclosed in the earlier application filed by the present applicant (Japanese Patent Application No. 2001-40570).

[0005]

According to a first aspect of the present invention, there is provided a processing container which is capable of being evacuated and an object to be processed which is provided in the processing container and which is to be processed at a predetermined temperature. The mounting table to be mounted on, the heating means having a zone heating unit for heating the object to be processed of the mounting table in a zone shape, and a heat treatment apparatus having a power supply means for supplying power to the heating means, Power control means for controlling the power supply means so as to raise the temperature of the object to be processed in a state where a temperature distribution is provided such that the temperature of the central portion of the object to be processed is high and the temperature of the peripheral portion is low. The power control means includes a limiter unit for limiting an operation amount. The invention as defined in claim 2 is characterized in that a processing container which is made evacuable, a mounting table which is provided in the processing container and on which an object to be processed at a predetermined temperature is mounted, A heating unit having a plurality of zone heating units that individually heat the object to be processed of the mounting table for each zone concentrically divided, and a power supply unit that supplies electric power to each zone heating unit of the heating unit. A temperature measuring unit provided corresponding to at least one of the concentric zones; and the processing object based on a detection value of the temperature measurement unit when the temperature of the processing object is raised. In a state where the temperature distribution is such that the temperature of the central part of the object is high and the temperature of the peripheral part is low, the object is raised to a warp safe temperature at least lower than the predetermined temperature. So that the And a power control means for controlling the supply means, said power control means is a heat treatment apparatus which is characterized in that it contains a limiter portion for limiting the manipulated variable.

According to a third aspect of the present invention, there is provided a processing container capable of being evacuated, and a mounting table provided in the processing container for mounting an object to be processed at a predetermined temperature on the processing container. A heating unit having a plurality of zone heating units for individually heating the object to be processed of the mounting table in each of the concentrically divided zones; and a power supply for supplying power to each zone heating unit of the heating unit. And a heat treatment apparatus having
Power detection means for measuring power supplied to each of the zone heating units of the power supply means or emitted from each of the zone heating units, and a detection value of the power detection means when the temperature of the object to be processed is raised. The object to be processed in a state where the object to be processed is provided with a temperature distribution such that the temperature of the central part of the object is high and the temperature of the peripheral part is low based on
Power control means for controlling the power supply means so as to raise the temperature to a warp safe temperature lower than at least the predetermined temperature, the power control means including a limiter unit for limiting the operation amount. A heat treatment apparatus.

According to a fourth aspect of the present invention, there is provided a processing container capable of being evacuated, and a mounting table provided in the processing container for mounting an object to be processed at a predetermined temperature on the processing container. Heating means having a zone heating unit for heating the object to be processed of the mounting table in a concentrically divided zone shape,
In a heat treatment apparatus having power supply means for supplying power to the heating means, a temperature measurement means provided corresponding to at least one of the concentric zones, and Based on the detection value of the temperature measuring means, the object to be processed in a state where the temperature of the object to be processed is given a temperature distribution such that the temperature of the central part of the object is high and the temperature of the peripheral part is low. Power control means for controlling the power supply means so as to raise the temperature to a warp safety temperature lower than at least the predetermined temperature, wherein the power control means includes a limiter unit for limiting the operation amount. A heat treatment apparatus characterized in that:

According to a fifth aspect of the present invention, there is provided a processing container which can be evacuated, and a mounting table which is provided in the processing container and which mounts an object to be processed at a predetermined temperature on the processing container. Heating means having a zone heating unit for heating the object to be processed of the mounting table in a concentrically divided zone shape,
In a heat treatment apparatus having a power supply unit that supplies power to the heating unit, a power detection unit that measures power released from each of the zone heating units of the power supply unit, and when the temperature of the object to be processed is increased. The object to be processed in a state where the object to be processed has a temperature distribution such that the temperature of the center of the object is high and the temperature of the peripheral part is low based on the detection value of the power detection means. Power control means for controlling the power supply means so as to raise the temperature to at least the warp safe temperature lower than the predetermined temperature, the power control means has a limiter unit for limiting the operation amount It is a heat treatment apparatus characterized by including. As described above, since the temperature is increased in a state where the temperature of the central portion of the processing target is high and the temperature of the peripheral portion is low, the processing target is warped and deformed. Therefore, it is possible to prevent peeling of the thin film and occurrence of an error in transporting the object to be processed.

In this case, for example, the limiter section may apply a fixed limiter constant to the operation amount so that the operation amount does not saturate when the temperature of the workpiece is raised. I have. Thus, a fixed limiter constant is applied to the operation amount so that the operation amount does not saturate, so that it is possible to prevent the temperature distribution from being disrupted in the temperature increasing process. In addition, for example, when the operation amount corresponding to one zone is saturated when the temperature of the object to be processed is saturated, the limiter unit can be changed to the operation amount of another zone in accordance with the saturation. To apply a typical output limit value. As a result, even if the operation amount of a certain zone becomes saturated, this result can be reflected in the operation amount of another zone, and as a result, this temperature increase can be performed without disturbing the temperature distribution of the object to be processed. It is possible to do.

In this case, for example, the output limit value is a ratio between the operation amount of the zone where the operation amount is saturated and the saturation operation amount. In addition, for example, a predetermined averaging constant is added to the arithmetic processing as defined in claim 9. Further, for example, as defined in claim 10, the safe warp temperature is in a range of 300 ° C or higher.

Further, for example, the power detector is any one of a current detector, a voltage detector, and a light amount detector. Further, for example, as defined in claim 12, the power control means is configured to control the power so that a temperature rising rate of the object to be processed is lower than a heat transfer rate from a central portion to a peripheral portion of the object to be processed. Control the supply means.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the processing apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a cross-sectional configuration diagram showing a processing apparatus according to the present invention, FIG. 2 is a configuration diagram showing a control system of a heating unit for heating a mounting table, and FIG. 3 is an example of a change in a temperature distribution when a temperature of a workpiece is raised. FIG. Here, a single wafer type film forming apparatus will be described as an example of the processing apparatus. As shown in the figure, the film forming apparatus 12 has a processing container 14 made of aluminum having a substantially cylindrical cross section, for example. A shower head 16 for introducing, for example, various film-forming gases as a process gas whose flow rate is controlled, is provided on a ceiling portion of the processing chamber 14 with a sealing member 17 such as an O-ring.
The film forming gas is injected toward the processing space S from a number of gas injection ports 18 provided on the lower surface.

The processing vessel 14 is covered on a cylindrical reflector 20 raised from the bottom of the processing vessel via, for example, three L-shaped holding members 22 (only two are shown in FIG. 1). A mounting table 24 for mounting a semiconductor wafer W as a processing body is provided. The reflector 20 is made of aluminum, and the holding member 22 is made of a heat-permeable material, for example, quartz.
The mounting table 24 is, for example, a carbon material having a thickness of about 1 mm,
It is made of a ceramic such as AlN. Below the mounting table 24, a plurality of, for example, three L-shaped lifter pins 26 (only two are shown in the illustrated example) are provided so as to stand upward, and the base of the lifter pin 26 is a ring. Commonly connected to the member 28. And
By moving the ring member 28 up and down by a push-up bar 30 provided through the bottom of the processing container, the lifter pins 26 can be inserted into lifter pin holes 32 provided through the mounting table 24 to lift the wafer W. It has become.

An extensible bellows 34 is interposed in the penetrating portion of the push-up bar 30 at the bottom of the container in order to keep the inside of the processing vessel 14 airtight. The lower end of the push-up bar 30 is connected to the actuator 36. Have been.
Further, an exhaust port 38 is provided at a peripheral edge of the bottom of the processing container 14, and an exhaust passage 40 connected to a vacuum pump (not shown) is connected to the exhaust port 38.
4 can be maintained at a predetermined degree of vacuum. A gate valve 42 that is opened and closed when a wafer is loaded and unloaded is provided on a side wall of the processing container 14.

A transmission window 44 made of a heat ray permeable material such as quartz is provided airtightly at the bottom of the processing container immediately below the mounting table 24 via a sealing member 46 such as an O-ring.
Below this, a box-shaped heating chamber 4 surrounding the transmission window 44 is provided.
8 are provided. In the heating chamber 48, a heating means 50 composed of, for example, a plurality of heating lamps is attached to a turntable 52 also serving as a reflecting mirror, and the turntable 52 is provided at the bottom of the heating chamber 48 via a rotation shaft. Rotary motor 54
Is rotated by Therefore, the heat rays emitted from the heating means 50 can pass through the transmission window 44 and irradiate the lower surface of the mounting table 24 to heat it. The heating means 50 is connected to a power supply means 56 for supplying power to the heating means 50.
Is controlled by power control means 58 composed of, for example, a microcomputer.

On the other hand, as shown in FIG.
A temperature measuring means 60, for example, composed of a thermocouple, is provided on the back side of the device for measuring the temperature of this portion. The measured value is supplied to the power control means 58. Specifically, here, the mounting table 24 is concentrically divided into a plurality of, for example, three zones 24A, 24B, and 24C. And each of the above zones 24
Thermocouples 60A, 60B, and 60C are respectively provided as the temperature measuring means 60 corresponding to A to 24C. The plurality of heating lamps forming the heating means 50 corresponding to each of the zones 24A to 24C of the mounting table 24 are three groups, that is, heating lamps (zone heating units).
It is divided into 50A, 50B and 50C. Accordingly, the inner heating lamp 50A mainly irradiates the inner zone 24A, the middle heating lamp 50B irradiates the middle zone 24B, and the outer heating lamp 50C mainly irradiates the outer zone 24C. I have. The power supply means 56 also includes three power supply units 56A, 56B, and 5 connected in correspondence with the three lamp groups 50A to 50C.
6C, and can be individually controlled for each of the lamps 50A to 50C. According to the present invention, when the temperature of the semiconductor wafer W is increased by the power control means 58, the temperature distribution is set so that the temperature of the central portion of the wafer W is high and the temperature of the peripheral portion is low. W can be heated to a predetermined temperature. Further, here, the power control means 58 is provided with a limiter section described later for always limiting the operation amount or when necessary, so as to prevent collapse of the temperature distribution in the wafer surface when the temperature of the wafer is raised. It has become.

Next, a description will be given of a control method performed by using the apparatus configured as described above. First, the gate valve 42 provided on the side wall of the processing container 14 is opened, the wafer W is loaded into the processing container 14 by a transfer arm (not shown), and the lifter pins 26 are pushed up to transfer the wafer W to the lifter pins 26. And the lifter pin 26
Is lowered by lowering the push-up bar 30, and the wafer W is mounted on the mounting table 24.

Next, a predetermined film-forming gas or the like is supplied as a processing gas from a processing gas source (not shown) to the shower head section 16 by a predetermined amount, and the gas is supplied substantially uniformly into the processing container 14 from the gas injection port 18 on the lower surface. To supply. At the same time, the inside of the processing container 14 is set to a predetermined degree of vacuum, for example, about 600 Pa by sucking and exhausting the internal atmosphere from the exhaust port 38, and each heating lamp 50 </ b> A of the heating means 50 located below the mounting table 24. Drive while rotating ~ 50C to radiate heat energy. The radiated heat rays pass through the transmission window 44 and then irradiate the back surface of the mounting table 24 to heat it. Since the mounting table 24 is very thin, about 1 mm as described above, it is quickly heated. Therefore, the wafer W mounted thereon is quickly heated to a predetermined temperature, for example, 550 ° C.
Can be heated to a degree. The supplied film-forming gas causes a predetermined chemical reaction, and a thin film is deposited and formed on the entire surface of the wafer.

Here, when the temperature of the semiconductor wafer W is raised by the conventional method, as shown in FIG. 4A, the entire surface of the wafer is heated at a uniform temperature, so that the heat moves from the back surface of the wafer to the front surface. As a result, the temperature difference between the front and back surfaces of the wafer has increased. On the other hand, in the method of the present invention, when the temperature of the semiconductor wafer W is raised, the temperature is raised in such a temperature distribution that the central portion of the wafer becomes higher and the peripheral portion thereof becomes lower. As described above, a component in which heat moves from the back surface of the wafer to the front surface and a component that moves from the center of the wafer to the side surface are formed. As a result, the temperature difference between the front and back surfaces of the wafer is reduced. More specifically, in the method of the present invention,
With the temperature distribution shown in FIG. 3, the temperature of the wafer W is raised to a predetermined temperature. That is, the detected values of the thermocouples 60A to 60C of the temperature measuring means 60 provided for each of the zones 24A to 24C of the mounting table 24 are determined by the power control means 58.
To the power supply means 5 based on these detected values.
By controlling the power supply units 56A to 56C of No. 6, the power supply amounts of the heating lamps 50A to 50C for each zone are determined. At this time, the amount of power supplied to each of the heating lamps 50A to 50C is naturally feedback-controlled so as to maintain the temperature distribution of the mounting table 24 as shown in FIG.

In FIG. 3, the passage of time flows upward from below in the graph, and shows the transition of the temperature distribution at predetermined intervals. That is, the temperature difference between the central portion and the peripheral portion of the mounting table 24 is approximately Δt ° C., and the central portion has a high temperature distribution, and the entire wafer is maintained while maintaining this temperature distribution state. Temperature goes up. Then, the temperature at the center of the wafer is set to 550, which is the set value.
When the temperature substantially reaches ° C, the temperature raising operation of only the peripheral portion is further continued for a certain period of time to set the entire temperature of the wafer W to the set value of 550 ° C. In this case, the temperature difference Δ
Although it depends on the diameter of the wafer W and the set value of the target temperature, t ° C. is, for example, about 10 to 30 ° C. when the wafer W is 300 mm (12 inches) in size.

If the temperature at the central portion of the wafer reaches a safe warp temperature, for example, 300 to 350 ° C., in the above-mentioned temperature raising process, the temperature is thereafter uniform and flat (not convex but flat). The temperature may be raised. The reason is that the thermal expansion coefficient of the constituent material of the wafer is lower in the temperature range above the safe warp temperature than in the temperature range around room temperature, so that the warping deformation stress is higher than the warp safe temperature. This is because the relaxation is achieved in the region of FIG. In this case, the rate of temperature rise of the wafer can be slightly increased. Here, the warp safe temperature refers to a temperature range in which the wafer AW does not undergo warp deformation even when the temperature is raised with a flat temperature distribution.

An important point here is that, as shown in FIG. 3, the temperature rising speed V1 of the semiconductor wafer W is set to be lower than the heat transfer speed V2 when heat is transferred from the center to the peripheral portion of the wafer. That is the point. That is, if the temperature rising speed V1 is too fast than the heat transfer speed V2, the heat transfer component from the back surface to the front surface of the wafer W increases, so that the difference in thermal expansion between the front surface and the back surface of the wafer W increases. Although warping deformation occurs in the wafer, as in the present embodiment, the wafer W
The temperature is raised while maintaining the temperature difference between the central portion and the peripheral portion of the wafer at about Δt ° C., and the wafer is warped by setting the temperature rising speed V1 to be lower than the heat transfer speed V2. It is possible to raise the temperature without lowering the throughput without lowering the throughput. Here, Δt ° C. is preferably in the range of about 10 ° C. to 30 ° C. from the viewpoint of preventing damage to the susceptor due to thermal stress and preventing warpage of the wafer. In this case, the temperature rise rate V1 of the wafer W is such that the wafer is not warped and deformed.
Moreover, it is preferable to set the speed in a speed range where the throughput is not significantly reduced, for example, about 10 ° C./sec.

The pressure in the processing chamber 14 at the time of raising the temperature of the wafer is set to 600 Pa, which is higher than the process pressure as described above in order to maintain relatively good thermal conductivity between the wafer W and the mounting table 24. Although the pressure is set to a degree, the pressure at the time of temperature rise is not limited to this. In the above embodiment, the mounting table 24
Although the heating lamps are individually provided for each of the zones, the present invention is not limited to this.If a desired temperature distribution is obtained, it is not necessary to provide a heating lamp for each zone, and a heating lamp smaller than the number of zones may be used. For example, a one-zone heating lamp may be used. Further, in the present embodiment, the power control means 58 is provided with limiters LIM1, LIM2, and LIM3 (see FIG. 5) for limiting the operation amounts of the respective zones. Always limit,
The operation amount is prevented from being saturated.

FIG. 5 is a block diagram showing an example of a control system of the power control means 58 in which control is performed based on such a method. In FIG. 5, reference numerals 62A, 62B, and 62C denote comparison units corresponding to the respective zones, which compare the set temperature values of the respective zones with the measured values from the thermocouples 60A to 60C, and output deviations. Reference numeral 64 denotes a control unit that performs control calculations based on deviations from the comparison units 62A to 62C to obtain the respective operation amounts U1, U2, and U3. Then, for each of the operation amounts U1 to U3 output from the control unit 64, a gain constant K that is variably set corresponding to each zone.
1, K2 and K3 are multiplied. Then, the output after the gain multiplication is limited by a limiter constant LC1 to LC3 predetermined in each of the limiters LIM1 to LIM3, and the output is output to each of the power supply units 56A to 56C. That is, each limiter unit LIM1
LIM3 operates as a fixed limiter. Here, for example, if the gain K1 corresponding to the inner peripheral zone 24A is "1", the other gain constants K2 and K3 are numerical values less than "1" so as to generate the temperature distribution as shown in FIG. Is set in advance. The thermocouple 6 in the inner zone
If the detected value of 0A reaches the set temperature which is the target value,
The other gain constants K2 and K3 also sequentially change toward "1", and finally the temperature over the entire surface of the wafer is maintained at the set temperature.

In this case, the limiters LIM1 to LIM1
In IM3, a positive limiter constant smaller than "1" is set for each operation amount. This value is, for example, LC1 = 0.
9, LC2 = C2 · LC1, LC3 = C3 · LC1, where C2 and C3 are averaging constants that are predetermined so that the power of each channel is averaged.
That is, Cj (j is a positive integer) sets the ratio of the operation amount of each channel in advance so that the temperature distribution shown in FIG. 3 can be maintained even when the operation amount of each channel is saturated. (Averaging constant). Also,
The meaning of LC1 = 0.9 is, for example, as follows. That is, when the input operation amount W1 of the power supply unit 56A exceeds a certain value, the output is saturated, but a certain value at this time is defined as W1 _SUS . When the input operation amount of the limiter unit LIM1 is V1 and the output operation amount is W1, the output of the limiter unit is W1 in the case of V1 <0.9 · W1 _SUS , and the case of V1 ≧ 0.9 · W1 _SUS . , The output of the limiter is 0.9 · W1 _SUS . Such a relationship is similarly performed in the other limiters LIM2 and LIM3. The input operation amounts are V2 and V3, respectively, and the output operation amounts are W2 and W3, respectively.
As a result, if the operation amount of some zones becomes saturated, the balance of the supplied heat amount is lost due to the saturation, and the temperature distribution at the time of temperature rise (see FIG. 3) cannot be maintained. By applying the limiter in this manner, the temperature rise rate is slightly reduced, but the temperature of the wafer can be surely raised while maintaining the temperature distribution as shown in FIG. As described above, by applying the fixed limiter constants LC1 to LC3 to the respective manipulated variables, the saturation of the manipulated variables is prevented, and the wafer is raised as quickly as possible without causing the temperature distribution to collapse. Can be warmed.

In the above embodiment, the thermocouples 60A to 60C are provided for each of the zones 24A to 24C of the mounting table 24. However, the present invention is not limited to this. For example, at least two thermocouples are required to detect a temperature distribution. May be provided. For example, inner zone 2
4A and the outer peripheral zone 24C are thermocouples 60A and 6C, respectively.
0C may be provided, and the temperature of the middle zone 24B may be controlled by taking, for example, an intermediate value between the detected values of the two thermocouples 60A and 60C. Also,
By further pushing the above idea, only one thermocouple may be provided, and power may be supplied to the other zones at a predetermined ratio so as to generate a temperature distribution as shown in FIG. FIG. 6 is a block diagram when such control is performed, and the thermocouple 60 is provided only in the inner peripheral zone 24A.
The case where A is provided is shown. In the control unit 64, based on the detected value of the thermocouple 60A and a predetermined power ratio, each of the operation amounts U2 of the other middle zone and the outer zone,
U3 is also calculated and obtained.

In each of the above embodiments, each limiter unit L
In IM1 to LIM3, the operation amount is always limited by a fixed limiter constant LIM1 to LIM3. However, the operation amount is not limited to this, and the operation corresponding to any one zone when the temperature of the wafer is increased is performed. When the amount is saturated, the final output operation amount may be limited by multiplying the operation amount of another zone by a variable output control value correspondingly. That is, here, it operates not as a fixed limiter but as a variable limiter. This allows
Even when the operation amount is saturated, the temperature of the wafer can be raised while maintaining the temperature distribution as shown in FIG. FIG. 7 shows a block diagram for performing such control. Control unit 6 in the figure
4 calculates the manipulated variables of the three channels corresponding to each zone. At this time, the channel in which the manipulated variable is saturated is tentatively set as the “i” channel, and the LI based on the control calculation is used.
An input operation of Mi Vi, the input operation amount when the power supply unit 56i causes saturation and Wi _sus. Then, the ratio Li of the two manipulated variables is defined as in the following equation. Li = Vi / Wi _sus

Then, based on the ratio Li, the limiter constant LCj of the other channel not causing saturation is calculated as in the following equation, and this is set to the limiter section of the other channel other than the saturated channel. It will be sent out as a constant. LCj = (Cj / Li) × (Vj / Wj _sus ) Here, Cj is an averaging constant predetermined so that the power of each channel is averaged as described above. According to the above control calculation, for example, when the operation amount of the channel in the inner peripheral zone is saturated, the following table is obtained. L1 = V1 / W1 _sus

As described above, when the manipulated variable corresponding to any one of the zones has a manipulated variable saturation, the manipulated variable of a channel not subject to the manipulated variable saturation is changed from the manipulated variable of a channel not subject to the manipulated variable saturation. The operation amount is dynamically restricted on the basis of the information. Therefore, even if the manipulated variable corresponding to any of the zones is saturated, the output manipulated variable of each channel is appropriately maintained, thereby maintaining the temperature distribution as shown in FIG. 3 more accurately. The temperature of the wafer can be increased while the wafer is being warped, so that it is possible to reliably prevent the wafer from being warped. Further, in the above description, the concept of clamping the operation amount Wj has been described as the concept of the limiter, but the idea of the present application is not limited to this. For example, in the case of a fixed limiter, it is possible to have a constant limiter constant in all zones and always multiply the input manipulated variable Vj by this limiter constant so that the output is not saturated. Further, even in the case of the variable limiter, when the operation amount is saturated in any zone, the operation amount can be limited immediately without waiting for the operation amount to be clamped in other zones. . Note that, in each of the above embodiments, as shown in FIG.
Although the temperature of these zones is directly measured in accordance with the above, the present invention is not limited to this, and zone heating units (heating lamps) corresponding to the above zones 24A to 24C are provided.
Power input to 50A-50C and each zone 24A-
Power detection means for detecting the power supplied to the 24C may be provided, and the power may be controlled based on each detection value of the power detection means.

FIG. 8 is a diagram in which current detectors 66A, 66B and 66C for detecting output currents from the power supply units 56A to 56C are provided as power detection means.
Are voltage detectors 68A, 68B, 6 for detecting output voltages from the respective power supply units 56A to 56C as power detection means.
8C shows a diagram provided with 8C. Then, based on the measured output current or output voltage, the power control means 58
Controls the power supplied to each of the heating lamps 50A to 50C. Further, as shown in FIG.
For example, the light amount detectors 70A, 70B, and 70C that detect the light amount by providing optical fibers and the like close to each other may be provided to detect the light amount of the heat rays from each of the heating lamps 50A to 50C. Then, based on the detection values of the light amount detectors 70A to 70C, the power control unit 58
The power supply to A to 50C will be controlled.

Accordingly, also in the case of the apparatus shown in FIGS. 8 to 10, the temperature difference between the central portion and the peripheral portion of the wafer W is Δt.
By raising the temperature while maintaining the temperature at about ° C., it becomes possible to raise the temperature without causing the wafer to be warped and without lowering the throughput. 8 to 10, at least one thermocouple is provided in order to directly measure the temperature of the mounting table 24. 8 to 10 show a case where a thermocouple 60A corresponding to the inner peripheral zone 24A is provided.

In the embodiment described above, the mounting table 2
FIG. 4 illustrates an example in which the power supplied to each of the zones 24A to 24C is controlled in order to realize the temperature distribution as shown in FIG. 3, but this operation method is not performed in addition to or without this operation method. Then, when the temperature of the wafer is raised, the processing container 1
The pressure in 4 may be reduced to a pressure below the viscous flow. In practice, the pressure below this viscous flow is 13
It refers to a pressure of 3 Pa (1 Torr) or less, and is a pressure in the region of molecular flow. Thereby, heat transfer between the mounting table 24 and the wafer W is dominated by conduction and radiation, and there is almost no heat transfer due to convection. Therefore, heat transfer between the two is slightly suppressed. As a result, the temperature rise rate of the wafer itself is suppressed and slowed down, and the component of heat transfer from the center of the wafer to the side surface increases, so that the temperature difference between the front surface and the back surface of the wafer is reduced accordingly. As a result, it is possible to prevent the wafer itself from being deformed by warpage.

Although a heating lamp composed of a point light source is used as the heating means here, the invention is not limited to this. For example, a linear light source lamp obtained by winding a filament or the like in a linear shape may be used. In this case, as shown in FIG. 11, for example, a plurality of, for example, four, linear heating lamps in which a filament 90 is wound in a linear manner may be provided and arranged. Here, the number of windings of the filament 90 is not uniform, and for example, the high-density portion 92A,
B, density is provided like low density portion 92C. By arranging the linear heating lamps 92 such that the high-density portion 92A is located on the center side of the turntable 52, FIG.
A zone-like temperature distribution as shown in FIG.

In this embodiment, the case where the mounting table 24 is divided into three zones has been described as an example. However, the number of divisions is not limited to this, and any number of divisions may be used as long as it is two or more. Also, here, the case where the zones are divided into concentric circles has been described. However, the present invention is not limited to this, and the mounting table may be divided into a plurality of circular zones. Further, the heating means is not limited to the heating lamp, and a resistance heater embedded in the mounting table may be used. Furthermore,
The present invention can be applied not only to a film forming apparatus but also to an etching process, an oxidation diffusion process, an annealing reforming process, and the like. Further, in this embodiment, a semiconductor wafer has been described as an example of an object to be processed, but the present invention is not limited to this, and it is needless to say that the present invention can be applied to an LCD substrate, a glass substrate, and the like.

[0035]

As described above, according to the heat treatment apparatus of the present invention, the following excellent functions and effects can be exhibited. According to the first to fifth and eighth to twelfth aspects of the present invention, the temperature is increased in a state where a temperature distribution is such that the temperature of the central part of the object to be processed is high and the temperature of the peripheral part is low. Therefore, it is possible to prevent the object to be warped from being deformed, thereby preventing the thin film from being peeled off and the transport error of the object to be processed from occurring. According to the sixth aspect of the present invention, a fixed limiter constant is applied to the operation amount so as not to saturate the operation amount, so that it is possible to prevent the temperature distribution from being disrupted in the temperature increasing process. According to the invention according to claim 7, even when the operation amount of a certain zone is saturated, the result can be reflected on the operation amount of another zone, and as a result, the temperature distribution of the object to be processed is reduced. This heating can be performed without breaking.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a processing apparatus according to the present invention.

FIG. 2 is a configuration diagram illustrating a control system of a heating unit that heats a mounting table.

FIG. 3 is a schematic diagram illustrating an example of a change in a temperature distribution when a temperature of a target object is raised.

FIG. 4 is a diagram showing a state of heat transfer when a temperature of a target object is raised by a conventional method and a method of the present invention.

FIG. 5 is a block diagram showing an example of a control system of a power control unit of the device of the present invention.

FIG. 6 is a block diagram showing an example of a control system of another modification of the power control means of the device of the present invention.

FIG. 7 is a block diagram showing an example of a control system of still another modification of the power control means of the device of the present invention.

FIG. 8 is a diagram showing a state where a current detector for detecting an output current from each power supply unit is provided as power detection means.

FIG. 9 is a diagram showing a state in which a voltage detector for detecting an output voltage from each power supply unit is provided as power detection means.

FIG. 10 is a diagram illustrating a state in which a light amount detector is provided as power detection means in correspondence with each zone to detect the amount of heat rays from each heating lamp.

FIG. 11 is a plan view showing a heating lamp according to a modification of the heating means in the present invention.

FIG. 12 is a schematic configuration diagram illustrating an example of a conventional heat treatment apparatus.

FIG. 13 is a schematic diagram showing a warped state of a semiconductor wafer on a mounting table.

FIG. 14 is a graph showing the relationship between the coefficient of thermal expansion of silicon and temperature.

[Explanation of symbols]

 Reference Signs List 12 film forming apparatus (heat treatment apparatus) 14 processing container 16 shower head section 24 mounting table 44 transmission window 50 heating means 50A to 50C heating lamp (zone heating section) 56 power supply means 56A to 56C power supply section 58 power control means 60 temperature Measurement means 60A to 60C Thermocouple 62 Comparison unit 64 Control unit 66A to 66C Current detector 68A to 68C Voltage detector 70A to 70C Photodetector LIM1 to LIM3 Limiter unit W Semiconductor wafer (workpiece)

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3K058 AA87 BA19 CA12 CA69 CB09 CB10 4K030 FA10 HA11 JA10 KA24 KA41 LA15 5F045 AA06 AF01 BB11 DP03 DQ04 EC03 EF05 EK14 EK22 EK27 EK30 EM09 EN04 GB04 GB05

Claims (12)

[Claims] 1. A processing container capable of being evacuated, a mounting table provided in the processing container, on which a processing target to be processed at a predetermined temperature is mounted, and a mounting table of the mounting table. In a heat treatment apparatus having a heating unit having a zone heating unit for heating a processing object in a zone shape, and a power supply unit for supplying power to the heating unit, a temperature of a central part of the processing target is high and a peripheral part is provided. Power control means for controlling the power supply means so as to raise the temperature of the object to be processed in a state where a temperature distribution is provided such that the temperature of the object becomes low. A heat treatment apparatus, comprising: 2. A processing container capable of being evacuated, a mounting table provided in the processing container, on which an object to be processed at a predetermined temperature is mounted, and a processing table mounted on the mounting table. In a heat treatment apparatus having a heating unit having a plurality of zone heating units for individually heating the processing body for each of the zones divided concentrically, and a power supply unit for supplying electric power to each zone heating unit of the heating unit. A temperature measuring means provided corresponding to at least one of the concentric zones; and a temperature measuring means provided on the processing target based on a detection value of the temperature measuring means when the temperature of the processing target is raised. In a state where a temperature distribution such that the temperature of the central part of the processing body is high and the temperature of the peripheral part is low is provided, the processing target is heated to at least a warp safe temperature lower than the predetermined temperature. The power supply means Gosuru and a power control unit, the power control unit is a heat treatment apparatus, characterized in that it includes a limiter unit for limiting the manipulated variable. 3. A processing container capable of being evacuated, a mounting table provided in the processing container, on which a processing object to be processed at a predetermined temperature is mounted, and a processing table mounted on the mounting table. In a heat treatment apparatus having a heating unit having a plurality of zone heating units for individually heating the processing body for each of the zones divided concentrically, and a power supply unit for supplying electric power to each zone heating unit of the heating unit. Power detection means for measuring power supplied to each of the zone heating units of the power supply means or emitted from each of the zone heating units; and detecting the power detection means when the temperature of the object to be processed is increased. Based on the value, the object to be processed in a state where a temperature distribution such that the temperature of the central part of the object is high and the temperature of the peripheral part is low, at least the predetermined temperature Lower warpage safety And a power control means for controlling said power supply means so as to warm to time, the power control unit is a heat treatment apparatus, characterized in that it includes a limiter unit for limiting the manipulated variable. 4. A processing container capable of being evacuated, a mounting table provided in the processing container for mounting an object to be processed at a predetermined temperature on the processing container, A heating unit having a zone heating unit that heats the processing body in a zone shape concentrically divided, and a heat treatment apparatus having a power supply unit that supplies power to the heating unit, wherein the concentric zone A temperature measuring unit provided corresponding to at least one zone, wherein the temperature of the central portion of the processing target is higher on the processing target based on a detection value of the temperature measuring unit when the temperature of the processing target is raised. Power control for controlling the power supply means so as to raise the temperature of the object to be processed to at least a warp safe temperature lower than the predetermined temperature in a state where a temperature distribution such that the temperature of the peripheral portion is lowered is provided. Means The heat treatment apparatus is the power control means, characterized in that it includes a limiter portion for limiting the manipulated variable. 5. A processing container capable of being evacuated, a mounting table provided in the processing container, on which a processing target to be processed at a predetermined temperature is mounted, and a processing table of the mounting table. In a heat treatment apparatus, comprising: a heating unit having a zone heating unit for heating a processing body in a zone shape concentrically divided; and a power supply unit for supplying power to the heating unit, wherein each of the zones of the power supply unit is Power detection means for measuring the power emitted from the heating unit; and, when the temperature of the object to be processed is increased, the temperature of the central part of the object to be processed is determined based on a value detected by the power detection means. A power for controlling the power supply means so as to raise the temperature of the object to be processed to at least a warp safe temperature lower than the predetermined temperature in a state where the temperature distribution is high and the temperature of the peripheral portion is low. Control means and A, the power control unit is a heat treatment apparatus, characterized in that it includes a limiter unit for limiting the manipulated variable. 6. The apparatus according to claim 1, wherein the limiter unit applies a fixed limiter constant to the operation amount so that the operation amount does not saturate when the temperature of the object is raised. The heat treatment apparatus according to any one of the above. 7. When the operation amount corresponding to one zone is saturated when the temperature of the object to be processed is increased, the limiter unit applies a variable output limit value to the operation amount of another zone in accordance with the saturation. The heat treatment apparatus according to claim 1, wherein: 8. The heat treatment apparatus according to claim 7, wherein the output limit value is a ratio between an operation amount of a zone where the operation amount is saturated and a saturation operation amount. 9. The arithmetic processing according to claim 7, wherein a predetermined averaging constant is taken into account.
The heat treatment apparatus according to the above. 10. The heat treatment apparatus according to claim 2, wherein the warpage safe temperature is in a range of 300 ° C. or higher. 11. The heat treatment apparatus according to claim 10, wherein the power detection unit is any one of a current detector, a voltage detector, and a light amount detector. 12. The power control unit controls the power supply unit such that a rate of temperature rise of the object to be processed is lower than a speed of heat transfer from a central part to a peripheral part of the object to be processed. The heat treatment apparatus according to any one of claims 1 to 11, wherein