JP2002334844A - Apparatus and method for heat treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem, when a wafer boat which carries many semiconductor wafers is carried in the reaction chamber of vertical type thermal treatment equipment, of a long time being required, until the temperature of the wafer is stabilized. SOLUTION: When the wafer boat is carried in the reaction chamber, a set temperature value which is different from a target temperature is outputted, and when, for example, the carrying-in operation of the boat is completed or before or after the carrying-in operation is completed, the set temperature value is changed toward a second set temperature value which corresponds to the target temperature. Here, what is referred to as the target temperature. The set temperature value which is different from the target temperature is a first set temperature value (or third set temperature value) which is lower (or higher) than the target temperature. It is also possible to output the first set temperature value, and when for example, the carrying-in operation of the wafer boat is completed or before or after the carrying-in operation is completed, to change the first set temperature value to the third set temperature value which is higher than the target temperature, and successively, to gradually lower the third set temperature value toward the target temperature.

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 and a heat treatment method for performing heat treatment on an object to be processed such as a semiconductor wafer.

[0002]

2. Description of the Related Art Semiconductor wafers (hereinafter referred to as "wafers")
As a device for performing batch heat treatment such as film formation by CVD (chemical vapor deposition), oxidation, diffusion, and the like, there is a vertical heat treatment device. In this apparatus, a vertical reaction vessel is provided in a heating furnace, a wafer holder is mounted on a lid that opens and closes a lower end opening of the reaction vessel, and a large number of wafers are held in a shelf shape by the wafer holder. After carrying the wafer holder into the reaction vessel by raising the lid, a predetermined heat treatment is performed.

For controlling the temperature inside the reaction vessel, an internal thermocouple provided inside the reaction vessel and an external thermocouple provided near the heater outside the reaction vessel are used, and these temperatures are detected by a temperature controller. The heat value (supplied power) of the heater is controlled based on the comparison result between the value and the temperature set value. FIG. 12 shows the profile of the temperature set value output from the temperature controller. The temperature is set during the loading operation for loading the wafer holder into the reaction vessel and thereafter until the temperature is stabilized. The value is P1. Thereafter, the temperature is increased to the process temperature P2 according to a predetermined pattern, and returns to P1 after the process. The timing to start increasing the temperature set value from P1 is set based on the timing at which the temperature of the wafer W is stabilized at the target temperature at the time of loading in advance, and based on the timing. How the temperature detection values of the internal thermocouple and the external thermocouple are incorporated into the control loop depends on the user. For example, the internal thermocouple or the external thermocouple may be used before the temperature starts rising from P1. It has been practiced to use the temperature detection values of a thermocouple and to use both temperature detection values at a predetermined timing after the start of temperature rise.

[0004]

By the way, since a large number of wafers are mounted on the wafer holder, when the wafer holder is carried into the reaction vessel, the temperature inside the reaction vessel temporarily drops. In this case, when the control is performed using the internal thermocouple, the temperature detection value is greatly reduced, so that a large amount of power is supplied to the heater and an overshoot occurs after the heater is carried in. FIG. 13 is a diagram showing this state. The dotted line, the solid line, and the chain line show the temperature set value (target temperature to be stabilized), the detected temperature in the reaction vessel (internal temperature), and the temperature of the wafer W, respectively. As can be seen from this figure, the detected temperature value begins to decrease after the start of loading of the wafer holder, and approaches the target temperature at the end of loading, but when the detected temperature value is low, a large amount of power is supplied to the heater. As a result, the heating value of the heater increases after the temperature drop in the reaction vessel, and as a result, the detected temperature value of the internal thermocouple is overridden. Accordingly, the internal temperature and the temperature of the wafer W are correspondingly increased. Takes a long time to stabilize at the target temperature.

If control is performed using an external thermocouple instead of an internal thermocouple, the temperature of the external thermocouple hardly decreases even if the temperature in the reaction vessel decreases, and the internal state cannot be detected. It takes a long time for the temperature to rise toward the target temperature. Here, if the temperature of the wafer W is increased without being stabilized at the target temperature, then the influence of the difference between the target temperature and the wafer temperature appears. Normally, the wafer mounting area of the wafer holder is divided into a plurality of upper and lower parts, and the heater is divided into a plurality of parts corresponding to this, so-called zone control is performed. It takes time to eliminate the difference between the temperature set value and the wafer temperature. As a result, it takes a long time to stabilize the temperature. Therefore, it is necessary to keep the temperature stable after loading the wafer.

Therefore, conventionally, there is a problem that it takes a long time until the temperature is stabilized after an object to be processed such as a wafer is carried into the reaction vessel, which causes a reduction in throughput.

The present invention has been made in view of the above circumstances, and an object of the present invention is to allow the temperature of an object to be processed to be rapidly stabilized after the object is carried into a reaction vessel. -To provide a heat treatment apparatus and a heat treatment method capable of improving the put.

[0008]

A heat treatment apparatus according to the present invention comprises:
A reaction vessel and a heating means are provided, and the object is carried into the reaction vessel. After the temperature of the object is stabilized at the target temperature at the time of carrying in, the temperature inside the reaction vessel is raised to or increased to the processing temperature. The present invention is directed to an apparatus for performing a heat treatment on an object to be processed at that temperature without heating, and one aspect of the present invention is to provide a temperature detection unit for detecting a temperature in the reaction vessel, A temperature set value output unit that outputs a first temperature set value lower than the target temperature when the wafer is carried in, and then outputs a second temperature set value corresponding to the target temperature; Means for comparing the output temperature set value with the result of temperature detection by the temperature detection unit, and controlling the amount of heat generated by the heating means based on the comparison result.

Specifically, the temperature set value output from the temperature set value output section increases from the first temperature set value to the second temperature set value at or before or after the completion of loading of the object to be processed. . In this case, for example, the temperature set value gradually increases from the first temperature set value toward the second temperature set value.

According to the present invention, in stabilizing the temperature of the object to be processed to the target temperature when the object is carried into the reaction vessel when the object is carried into the reaction vessel, the inside of the reaction vessel is cooled by carrying the object to be treated, The temperature overshoots based on the initial small temperature set value, and the second temperature which is the target temperature is
Therefore, the temperature of the object to be processed quickly stabilizes at the target temperature.

In another aspect of the invention, the temperature set value output section outputs a third temperature set value higher than the target temperature when the object to be processed is carried into the reaction vessel, and thereafter outputs a second temperature set value corresponding to the target temperature. Is output. Specifically, the temperature set value gradually decreases, for example, from the third temperature set value to the second temperature set value before or after the completion of the loading of the object to be processed.

According to still another aspect of the present invention, the temperature set value output section outputs a first temperature set value lower than the target temperature when the object to be processed is carried into the reaction vessel, and then outputs the first temperature set value. It is configured to output a high third temperature set value, and then output a second temperature set value corresponding to the target temperature. Specifically, the temperature set value rises, for example, instantaneously from the first temperature set value to the third temperature set value at or around the end of the loading of the object to be processed, and then from the third temperature set value to the third temperature set value. For example, the temperature gradually decreases toward the temperature set value of 2.

According to these inventions, the object to be processed can be quickly stabilized at the target temperature at the time of carrying in. However, the pattern of the invention in which the temperature set value is changed depends on the target temperature at the time of carrying in and the apparatus configuration. An optimal pattern may be selected according to the situation.

The temperature set value output section includes a plurality of time change patterns of the temperature set values for stabilizing the temperature when the workpiece is carried in. You may be comprised so that the pattern according to the number of to-be-processed objects hold | maintained by a holder may be selected. Alternatively, the temperature set value output unit includes a plurality of temporal change patterns of the temperature set values for stabilizing the temperature at the time of carrying in the object to be processed. May be configured to select a pattern according to the carry-in speed.

Further, in the heat treatment method of the present invention, the object to be processed is carried into the reaction vessel, and the heating means is controlled based on a result of comparison between the set temperature value and the detected temperature value in the reaction vessel. The present invention is directed to a method of performing a heat treatment by heating the first temperature set value to a first temperature set value lower than a second temperature set value corresponding to a target temperature at the time of carrying in an object to be processed. Setting and carrying the object into the reaction vessel; and then setting the temperature set value to a second temperature set value higher than the first temperature set value; and After the temperature is stabilized at the temperature set value of 2, the step of heating the inside of the reaction vessel to the processing temperature or performing a heat treatment on the object at that temperature without raising the temperature. . Note that the change pattern of the temperature set value may be a pattern similar to that of the other and further inventions of the above-described heat treatment apparatus.

As a heat treatment apparatus to which the present invention is applied,
A large number of workpieces are placed on a holder and carried into the reaction vessel, and the heating means may be a batch type heater which is a heater provided outside the reaction vessel. In this case, for example, the heater is divided in the longitudinal direction of the reaction vessel, and the temperature detecting section is provided in an area where the temperature is controlled by the divided heaters. Means for controlling the heat generation amount are provided for each heater.

[0017]

FIG. 1 is an overall configuration diagram of an embodiment in which the present invention is applied to a vertical heat treatment apparatus. First, the overall configuration of this vertical heat treatment apparatus will be briefly described. This apparatus is, for example, a double tube made of, for example, quartz made of an inner tube 1a having both ends open and an outer tube 1b having an upper end closed. A reaction tube 1 having a structure is provided. A cylindrical heat insulating body 21 is fixedly provided on a base body 22 around the reaction tube 1. Inside the heat insulating body 21, a heater 3 composed of a resistance heating element is divided into a plurality of parts, for example, vertically. It is provided. The number of divisions is, for example, five. In this example, for convenience, three-stage division (3a,
3b, 3c). As the heater 3, a carbon wire formed by weaving a plurality of bundles of high-purity carbon fibers having a wire diameter of, for example, about 10 microns is used as a ceramic, for example, a transparent quartz tube having an outer diameter of more than ten millimeters. Can be used sealed inside
For example, it is formed in a wave shape along the circumferential direction of the heat insulator 21.
The heater 3 is not limited to this, but may be a metal body such as an iron-tantalum-carbon alloy.

The inner pipe 1a and the outer pipe 1b are supported on a cylindrical manifold 23 at the lower side.
3, a gas supply pipe 24 is provided so that a supply port is opened in a lower region inside the inner pipe 1a, and one end is connected to a vacuum pump (not shown) so as to exhaust air from between the inner pipe 1a and the outer pipe 1b. The exhaust pipe 25 whose side is connected is connected.
In this example, a reaction vessel is constituted by the inner tube 1a, the outer tube 1b, and the manifold 23.

Further, a lid 11 is provided so as to close the lower end opening of the manifold 23, and the lid 11 is provided with a ball.
It is provided on the elevator 12. A rotary table 15 is provided on the lid 11 via a rotary shaft 14 by a driving unit 13, and a wafer holder as a substrate holder is provided on the rotary table 15 via an insulating unit 16 formed of, for example, a heat insulating cylinder. 17 is mounted. The wafer boat 17 is configured so that a large number of wafers W, which are substrates, can be placed on a shelf.

The lid 11 has a thin quartz tube 40 for thermocouples.
Are raised in the heat treatment atmosphere in the inner tube 1a and penetrate therethrough. In the quartz tube 40, for example, the heat treatment atmosphere of each heater 3 (3a, 3b, 3c) divided into three stages is provided. The internal temperature detector 3 detects the temperature respectively.
The internal thermocouples 4 (4a, 4b, 4c) are provided. A heater 3 between the inner pipe 1a and the outer pipe 1b.
In the vicinity of (3a, 3b, 3c), heaters 3 (3
External thermocouples 5 (5a, 5b, 5c) are provided as external temperature detectors for detecting the temperatures a, 3b, 3c, respectively.

The heaters 3 (3a, 3b, 3
c) a control unit 6 (6a, 6a) for controlling the heat value for each
b, 6c) are provided, and each control unit 6 (6a, 6c) is provided.
b, 6c) are, for example, internal thermocouples 4 (4a, 4b, 4).
c) and the external thermocouple 5 (5a, 5b,
Based on the detected temperature value and the set temperature value according to 5c),
It is configured to control the amount of heat generated by controlling the power supplied to the heater 3 (3a, 3b, 3c). The internal thermocouple 4 (4
The signal lines a, 4b, and 4c) are drawn from the lower side of the quartz tube 40 outside the lid 11, but are shown for convenience in FIG.

Since the control units 6 (6a, 6b, 6c) have the same configuration, one of them will be described with reference to FIG. In FIG. 2, reference numeral 61 denotes a temperature set value output unit for outputting the temperature set value of the heat treatment atmosphere in the inner tube 1a, and stores a temperature pattern which is a set value of the temperature set values at each timing. When the wafer W is loaded, a first temperature set value T1 is output, and after the wafer W is loaded, the temperature pattern increases toward a second temperature set value that is larger than the first temperature set value. Are set to rise to the process temperature after stabilizing to the second temperature set value, and to decrease to the first temperature set value after the process is completed.

On the output side of the temperature set value output section 61, a comparison operation section 62 for comparing the temperature set value with the temperature detection results of the internal thermocouple 4 and the external thermocouple 5 (detecting a difference) is provided. I have. The temperature detection results of the internal thermocouple 4 and the external thermocouple 5 are, for example, a value obtained by mixing the temperature detection value of the internal thermocouple 4 and the temperature detection value of the external thermocouple 5 at a predetermined ratio in the mixing unit 63 (internal temperature Detection value x Y% + external temperature detection value x (10
0-Y)%). In this example, after the wafer W is loaded, the internal temperature detection value, which is the temperature detection value of the internal thermocouple 4, is used as the temperature detection result until the inside of the inner tube 1a is stabilized at the second temperature set value T2 (that is, Y). = 100)
However, an external temperature detection value which is a temperature detection value of the external thermocouple 5 may be mixed. After the temperature is stabilized at the second temperature set value T2, for example, a value obtained by mixing both at a predetermined ratio is used, and there are various methods of using the values of both.

An amplifier 63 is provided on the output side of the comparison operation unit 62. The amplifier 63 amplifies the comparison result (operation signal) of the comparison operation unit and supplies the electric power supplied from the power supply unit 31 to the heater 3. Is output as a control signal of the switch unit 32 for controlling The control unit 6 is actually, for example, a CPU,
It is composed of a ROM storing a program, a memory storing a temperature set value, and the like. Output of the temperature set value is performed by reading data from the memory, and each operation is performed by software by the program. FIG. 2 schematically shows the image configuration.

Next, the operation of the above embodiment will be described. First, a number of wafers W to be processed are transferred to a wafer boat 17 below the reaction vessel (reaction tube 1 and manifold 23) and held in a shelf shape, and the boat elevator 12 is raised. Then, the wafer boat 17 (wafer W) is carried into the reaction vessel. On the other hand, the first temperature set value T1 is output from the temperature set value output unit 61, and at this stage, the ratio of the temperature detected value of the internal thermocouple 4 in the mixing unit 63 is set to 10
The detected temperature value is input to the comparison operation unit 62 as 0%, and the power supplied to the heater 3 is controlled based on the deviation.

FIG. 3 is a diagram schematically showing a temperature set value and a temperature detection value (internal temperature detection value) of the internal thermocouple 4 for explaining the operation of this embodiment. In this example, the wafer temperature in FIG. 3 is a temperature detection value of a temperature detection unit provided on a wafer positioned at the middle stage of the wafer boat 17. Until time t1 when the loading of the wafer boat 17 is started, the temperature set value is the first temperature set value indicated by the dotted line, and the detected internal temperature is substantially stable at the first temperature set value. Then, when the loading of the wafer boat 17 is started at time t1, that is, when the upper end of the wafer boat 17 enters the reaction vessel, the wafer boat 17 is cooled at room temperature, so that the heat in the reaction vessel is reduced. And the internal temperature (internal temperature detection value) decreases as indicated by the solid line. After the lid 11 is raised to almost close the lower end opening of the manifold 23, the ascending speed is reduced and the opening is closed gently, and the loading is completed at time t2. In this example, the timing t0 at which the detected internal temperature is the lowest in FIG.
1 is when the opening is almost closed,
At this point, the internal temperature detection value has started to rise.

As described above, when the wafer boat 17 is loaded, the internal temperature detection value becomes lower than the first temperature set value, so that the output of the amplifier 63 increases according to the deviation, and the output to the heater 3 is increased. The supplied power is increased, and the amount of heat generated by the heater 3 is increased. However, since there is a time delay from when the power supplied to the heater 3 becomes large to when the temperature inside the reaction vessel rises, the internal temperature rises even after the loading of the wafer boat 17 is completed (after time t2). And the first temperature set value T1
Overshoot. Incidentally, the first temperature set value T1 is lower than the target temperature T2 at which the inside of the reaction vessel is to be stabilized after the loading is completed. Therefore, for example, at time t2 when the loading is completed, the temperature set value from the temperature set value output unit 61 is gradually increased from the first temperature set value to the second temperature set value as the target temperature while gradually increasing. I will do it. The switching of the temperature set value can be grasped on a program or a switch for detecting that the lid 11 is completely closed, for example, on a device controller which controls the control of the entire vertical heat treatment device. Control unit 6 (6
a, 6b, 6c).

The temperature set value is equal to the second temperature set value T2.
, The internal temperature, which has risen by overshooting the first temperature set value, tends to converge to the second temperature set value, and at time t3, the second internal temperature rises. Stabilizes at the temperature setting. Therefore, the temperature of the wafer W quickly converges to the temperature set value T2 without causing a large overshoot as in the related art (see FIG. 13). In addition, R in FIG. 3 is a temperature stabilization time after completion of carrying in. Such an operation is obtained in each divided region assigned to the heater 3 in each stage, and the temperature of the wafer W is stabilized at the target temperature set in each divided region.

Thereafter, as described in the section of the conventional example (see FIG. 5), the temperature set value increases and the temperature inside the reaction vessel rises.
After the wafer W is stabilized at the process temperature, the gas supply pipe 24
A predetermined processing gas, for example, a film forming gas is supplied into the reaction vessel from the apparatus, and is maintained at a predetermined degree of vacuum by a vacuum pump (not shown) via an exhaust pipe 25. A film forming process, which is a heat treatment, is performed on W. Thereafter, the temperature set value decreases and the temperature inside the reaction vessel drops. For example, after the temperature reaches the first temperature set value, the boat elevator 12 descends and the wafer boat 17 is carried out. In the actual temperature control, a program is set so that the timing at which the wafer W is stabilized at the target temperature at the time of loading is grasped, and the temperature is raised toward the process temperature at that timing.

According to the above-described embodiment, when the wafer boat is carried into the reaction vessel, the first temperature lower than the target temperature.
The temperature set value is output, and thereafter, the temperature is increased toward the second temperature set value corresponding to the target temperature. Therefore, the inside of the reaction vessel is cooled by carrying in the wafer boat and the first first temperature is set. Although the temperature is overdriven based on the temperature set value, the overtemperature is used to approach the second temperature set value, which is the target temperature. As a result, both the internal temperature and the temperature of the wafer W are reduced. As will be apparent from the test examples described later, the target temperature is rapidly stabilized to the target temperature, which contributes to the improvement of the throughput.

Here, the apparatus shown in FIG. 1 is used, and the number of heaters is divided into five stages. The temperature in the reaction vessel and the temperature of the wafer W corresponding to the lowermost stage are set to the same values as in the prior art. FIG. 4 shows the results of the investigation when the temperature is not changed and when the temperature is set to two levels as in the present invention.
Solid lines a1 and b1 are the conventional internal temperature detection value and the internal temperature detection value of the present invention, respectively, and solid lines a2 and b2 are the conventional wafer temperature and the wafer temperature of the present invention, respectively. The target temperature is 590 ° C., and the first temperature set value is 576 ° C. As can be seen from FIG. 4, in both cases, the temperature inside the reaction vessel has been temporarily lowered by carrying in the wafer boat.
The time required for the present invention to stabilize at the target temperature is shorter than that of the related art.

In the above-described embodiment, the process is performed by raising the temperature after the inside of the reaction vessel is stabilized at the target temperature.
The case where the process is carried out at the target temperature without raising the temperature after stabilization to the target temperature is also included in the scope of the invention. In addition, the method of increasing from the first temperature set value toward the second temperature set value may be increased linearly, may be increased stepwise, and may be further increased rapidly. Is also good. The timing of increasing from the first temperature set value toward the second temperature set value is such that the effect of shortening the time until the temperature stabilizes can be obtained as compared with the related art.
Any timing is included in the scope of the present invention. Next, another embodiment of the present invention will be described with reference to FIG. In the above embodiment, the temperature set value is initially set lower than the target temperature T2, and the wafer boat 17
Is gradually increased to the target temperature T2 after the completion of the loading, but in this embodiment, as shown by the dotted line, the temperature set value is initially set to the third temperature set value T3 higher than the target temperature T2, After the loading of the wafer boat 17 is completed, the temperature is gradually lowered to the second temperature set value T2 which is the target temperature. This embodiment is different from the temperature set value output unit 61 shown in FIG.
Has the same configuration as that of the previous embodiment except that a part of the temperature pattern stored in is stored as shown in FIG. In this case, the temperature set value is not limited to the time when the loading of the object is completed, and may be set to decrease from the third temperature set value to the second temperature set value before and after that.

In this example, the detected value of the internal temperature in the reaction vessel is the time t at which the loading of the wafer boat 17 is started.
Up to 1 is substantially stable at the third temperature set value T3,
When the loading of the wafer boat 17 is started at time t1, the internal temperature (internal temperature detection value) decreases as indicated by the solid line as already described in detail, and starts to rise at time t0, and the loading is completed. At time t2, the temperature returns to temperature T3. Thereafter, if the temperature set value remains at T3, the internal temperature rises beyond T3 due to an increase in the amount of heat generated by the heater 3 in accordance with the difference between the temperature set value during loading and the detected internal temperature. When the temperature set value decreases from T3 toward the second temperature set value T2, which is the target temperature, the internal temperature also decreases and attempts to converge on the second temperature set value, and at time t
At 3, the temperature is stabilized at the second temperature set value.

In this embodiment, since the vertical fluctuation of the internal temperature after loading the wafer is small, as a result, the temperature of the wafer W is more quickly stabilized to the target temperature than in the prior art, contributing to the improvement of the throughput. I do. The method of setting the initial set temperature higher than the target temperature in this manner is suitable when the target temperature T2 at the time of loading the wafer is relatively low. The reason is that when the target temperature T2 is low, the wafer W
If the temperature at the time of loading is lower than the target temperature, the temperature rise rate of the wafer W is further reduced, and it takes time until the temperature of the wafer W converges to the target temperature. This is because increasing the internal temperature of the reaction vessel quickly raises the temperature of the wafer W, and as a result, the time required for the wafer W to stabilize at the target temperature T2 is reduced. When the target temperature at the time of loading is low, the method shown in FIG. 5 is better than the method shown in FIG.
Even if the method is used, the temperature stabilization time is shorter than that of the conventional method.

FIG. 6 shows a case where the apparatus shown in FIG. 1 is used and the number of heater divisions is set to five, and the temperature in the reaction vessel corresponding to the lowest one is not changed as in the conventional case. These are the results of a study on a case where two levels of temperature setting values are provided as shown in FIG. Solid lines a1 and b1 are the conventional internal temperature detection value and the internal temperature detection value of the present invention, respectively, and solid lines a2 and b2 are the conventional wafer temperature and the wafer temperature of the present invention, respectively. The target temperature is 300 ° C., and the third temperature set value is 390 ° C. As can be seen from FIG. 6, with respect to the time until the internal temperature stabilizes at the target temperature, the method of the present invention is later than the conventional case. The invention is shorter than before.

Referring to still another embodiment of the present invention, FIG. 7 is a view showing the entire structure of a vertical heat treatment apparatus used in this embodiment. This device differs from the structure of FIG. 1 in the following points. That is, as the heater 7 (use “7” to distinguish it from FIG. 1), it is responsible for heating all the regions of the arrangement region of the wafer W, or almost all regions except the upper and lower parts of the arrangement region of the wafer W And a pair of sub-heaters 7a and 7 which are provided above and below the main heater 7b and form a heat treatment atmosphere at the upper end and the lower end of the reaction tube 1, respectively.
c. As a material of the heater 7, for example, a material obtained by sealing a carbon wire in ceramics, for example, a quartz tube can be used. The heat insulating unit 16 includes a heater 16a and is mounted on the lid 11, and a rotation shaft 14 for rotating the wafer boat 17 penetrates the center. 70 is a ceiling heater.

In the heat treatment apparatus having such a structure,
Depending on the temperature range of the target temperature when the wafer boat 17 is loaded, it is advisable to set the temperature set value higher than the target temperature initially in the low temperature range as shown in FIG. There is a large temperature difference between the upper stage side of the wafer boat 17 carried into the lower stage and the lower stage side introduced later. In such a situation, that is, once a large temperature difference occurs between the wafers, if the heating control of the wafer W from the upper stage to the lower stage is uniformly performed by the long main heater 7b, it takes a long time to correct the temperature difference. Take it.

Therefore, in such an apparatus, as shown in FIG. 8, the temperature set value is set to the first temperature set value T1 lower than the target temperature T2 until the loading of the wafer boat 17 is completed (time t2). At t2, it is preferable that the temperature be raised at once to a third temperature set value T3 higher than the target temperature T2, and then be gradually lowered toward the target temperature T2. In this example, when the wafer boat 17 is loaded, the temperature inside the reaction vessel is low, so the temperature difference in the length direction of the wafer boat 17 (the temperature difference between the surfaces of the wafers W) is small. Further, at the end of loading, the temperature set value is raised to T3 at a stretch, so that the temperature rising rate of the wafer W increases, and then gradually decreases toward the target temperature T2. The temperature quickly converges to the target temperature T2. According to such a method, the temperature stabilization time is shorter than that of the conventional method even though the method of FIGS. 3 and 5 is more advantageous than the method of FIGS. In this embodiment, the temperature set value may rise instantaneously from the first temperature set value to the third temperature set value before and after the completion of the loading of the object to be processed, not only at the end of the loading of the object.

FIG. 9 shows a case in which the apparatus shown in FIG. 7 is used to change the temperature in the vicinity of the central portion in the longitudinal direction in the reaction vessel as in the conventional case where the temperature set value is not changed. These are the results of an investigation with and without a change. Solid lines a1 and b1 are the conventional internal temperature detection value and the internal temperature detection value of the present invention, respectively, and solid lines a2 and b2 are the conventional wafer temperature and the wafer temperature of the present invention, respectively. The target temperature is 400 ° C., the temperature set value is initially 380 ° C., and is raised to 460 ° C. at a stretch after the loading is completed. As can be seen from FIG. 9, the method of the present invention is delayed from the conventional case with respect to the time until the internal temperature stabilizes at the target temperature. The invention is shorter than before.

Here, in the present invention, the temperature set value output unit 61
For example, when a pattern shown in FIG. 5 is prepared as a temporal change pattern (temperature set value pattern) of the temperature set value output from the controller, a plurality of patterns are prepared according to the number of product wafers W mounted on the wafer boat 17. You may.
FIG. 10 shows the configuration of a control unit for implementing such a method. The batch size table 81 is data for associating the batch size with the number of product wafers for one batch to be subjected to heat treatment. What is batch size?
For example, assuming that the number of product wafers is 100 when the product wafers W are fully loaded on the wafer boat 17, the product wafers are divided into four sizes, for example, 100, 50, and 25. 25 sheets size (L25) for 1-35 sheets, 50 for 36-65 sheets
The sheet size (L50) and 66 to 100 sheets are classified as 100 sheet size (L100). The number of product wafers for one batch is determined by the wafer counter 8 on the control unit side of the apparatus.
The batch size is known from the batch size table 81 because the batch value is known from the count value from 2 and the like.

On the other hand, a storage section 83 serving as a temperature set value output section stores data in which a batch size and a temperature set value pattern are associated with each other. A set value pattern is selected, and temperature control is performed. 85 is a CPU. For example, when the temperature set value is changed as shown in FIG. 5, the smaller the batch size, the lower the value of the third temperature set value T3, and from the third temperature set value T3 to the first temperature set value T
The timing to shift to 2 is made earlier.

Depending on the apparatus configuration, if the temperature set value pattern when the batch size is large is used when the batch size is small, the temperature of the wafer W may be excessively high and overshoot may occur. By employing this, the temperature of the wafer W can be quickly stabilized at the target temperature T2 regardless of the size of the batch size.

Further, in the present invention, as shown in FIG. 11, various temperature set value patterns are prepared in the storage unit 91 corresponding to various loading speeds of the wafer W (elevating speed of the wafer boat 17). When the carry-in speed is selected by the carry-in speed selecting section 92, the corresponding temperature set value pattern may be selected. In this case, for example, if the temperature set value pattern shown in FIG. 8 is used, when the transfer speed is high, the temperature difference between the wafers W at the time of transfer is small, so the first temperature set value T1 is increased and the third temperature is set. The setting value T3 may be lowered, and when the loading speed is low, the setting may be reversed. By doing so, the temperature of the wafer W can be quickly stabilized at the target temperature T2 regardless of the loading speed.

[0044]

As described above, according to the present invention, after the object to be processed is loaded into the reaction vessel, the temperature of the object to be processed can be quickly stabilized at the target temperature at the time of loading. Can be improved.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view showing a vertical heat treatment apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a control unit used in this embodiment.

FIG. 3 is an explanatory diagram showing the operation of this embodiment.

FIG. 4 is an explanatory diagram showing an experimental result for confirming the effect of the present invention.

FIG. 5 is an explanatory diagram showing the operation of another embodiment of the present invention.

FIG. 6 is an explanatory diagram showing an experimental result for confirming an effect of another embodiment.

FIG. 7 is a longitudinal sectional side view showing a vertical heat treatment apparatus suitable for still another embodiment of the present invention.

FIG. 8 is an explanatory diagram showing the operation of still another embodiment of the present invention.

FIG. 9 is an explanatory diagram showing an experimental result for confirming an effect of still another embodiment.

FIG. 10 is a block diagram showing a control unit according to still another embodiment of the present invention.

FIG. 11 is a block diagram showing a control unit according to a further embodiment of the present invention.

FIG. 12 is an explanatory diagram showing an example of a temperature profile in a conventional vertical heat treatment apparatus.

FIG. 13 is an explanatory diagram showing a temperature change in a reaction vessel in a conventional vertical heat treatment apparatus.

[Explanation of symbols]

 1a Inner tube 1b Outer tube 1 Reaction tube 11 Lid 17 Wafer boat 23 Manifold 24 Gas supply tube 25 Exhaust tube 3 (3a, 3b, 3c) Heater 32 Switch section 4 (4a, 4b, 4c) Inside Thermocouple 5 (5a, 5b, 5c) External thermocouple 6 (6a, 6b, 6c) Control unit 61 Temperature setting output unit 62 Comparison operation unit 63 Mixing unit

Claims (20)

[Claims] An object is provided with a reaction vessel and a heating means. The object is carried into the reaction vessel. After the temperature of the object is stabilized at the target temperature at the time of carrying in, the inside of the reaction vessel is heated to the processing temperature. In an apparatus for performing a heat treatment on an object to be processed at that temperature without heating or raising the temperature, a temperature detection unit that detects a temperature in the reaction container; and loading the object into the reaction container. A temperature set value output unit that outputs a first temperature set value lower than the target temperature, and then outputs a second temperature set value corresponding to the target temperature; Means for comparing a temperature set value and a temperature detection result by the temperature detection unit, and controlling a calorific value of the heating means based on the comparison result;
A heat treatment apparatus comprising: 2. The temperature setting value output section is configured such that the temperature setting value increases from the first temperature setting value to the second temperature setting value at or before or after the completion of loading of the object to be processed. The heat treatment apparatus according to claim 1, wherein: 3. The temperature set value output section outputs a first temperature set value.
3. The heat treatment apparatus according to claim 2, wherein the heat treatment apparatus is configured to gradually increase from the temperature set value to the second temperature set value. 4. A reaction vessel and a heating means are provided, and the object is carried into the reaction vessel. After the temperature of the object is stabilized at a target temperature at the time of carrying in, the inside of the reaction vessel is heated to a processing temperature. In an apparatus for performing a heat treatment on an object to be processed at that temperature without heating or raising the temperature, a temperature detection unit that detects a temperature in the reaction container; and loading the object into the reaction container. A temperature set value output unit that outputs a third temperature set value higher than the target temperature, and then outputs a second temperature set value corresponding to the target temperature; Means for comparing a temperature set value and a temperature detection result by the temperature detection unit, and controlling a calorific value of the heating means based on the comparison result;
A heat treatment apparatus comprising: 5. The temperature set value output section is configured such that the temperature set value decreases from the third temperature set value to the second temperature set value at or before or after the completion of loading of the object to be processed. The heat treatment apparatus according to claim 4, wherein: 6. A temperature set value output section, wherein the temperature set value is a third set value.
The heat treatment apparatus according to claim 5, wherein the heat treatment apparatus is configured to gradually decrease from the temperature set value to the second temperature set value. 7. A reaction vessel and a heating means are provided, and the object is carried into the reaction vessel. After the temperature of the object is stabilized at the target temperature at the time of carrying in, the inside of the reaction vessel is heated to the processing temperature. In an apparatus for performing a heat treatment on an object to be processed at that temperature without heating or raising the temperature, a temperature detection unit that detects a temperature in the reaction container; and loading the object into the reaction container. Sometimes, first, a first temperature set value lower than the target temperature is output, then a third temperature set value higher than the target temperature is output, and then a second temperature set value corresponding to the target temperature is output. A temperature set value output unit that performs temperature comparison between a temperature set value output from the temperature set value output unit and a temperature detection result obtained by the temperature detection unit, and controls a heat generation amount of the heating unit based on the comparison result. Means,
A heat treatment apparatus comprising: 8. The temperature set value output section instantaneously rises from the first temperature set value to the third temperature set value at or before or after the completion of loading of the object to be processed, and then sets the third temperature set value. The heat treatment apparatus according to claim 7, wherein the heat treatment apparatus is configured to gradually decrease from the temperature set value to the second temperature set value. 9. The apparatus according to claim 1, wherein a large number of objects to be processed are mounted on a holder and carried into the reaction vessel, and the heating means is a heater provided outside the reaction vessel. The heat treatment apparatus according to any one of the above. 10. The temperature set value output unit includes a plurality of time change patterns of temperature set values for stabilizing the temperature at the time of carrying in an object to be processed, and includes a plurality of time change patterns of the plurality of temperature set values. 10. The heat treatment apparatus according to claim 9, wherein a pattern according to the number of objects to be processed held by the holder is selected. 11. The temperature set value output section includes a plurality of time change patterns of the temperature set values for stabilizing the temperature at the time of carrying in the object to be processed, and includes a plurality of time change patterns of the plurality of temperature set values. 10. The heat treatment apparatus according to claim 9, wherein a pattern according to the carrying speed of the holder is selected. 12. A heater is divided in the longitudinal direction of the reaction vessel, and a temperature detector is provided in an area where the temperature is controlled by each of the divided heaters. The heat treatment apparatus according to any one of claims 9 to 11, wherein a means for controlling the amount of heat generated is provided for each heater. 13. An object to be processed is carried into a reaction vessel, and a heating means is controlled based on a comparison result between a set temperature value and a detected temperature value in the reaction vessel to heat the object to perform heat treatment. In the performing method, the temperature set value is set to a first temperature set value lower than a second temperature set value corresponding to a target temperature at the time of carrying in the object, and the object is carried into the reaction vessel. A step of subsequently setting a temperature set value to a second temperature set value higher than the first temperature set value; and after the temperature of the object to be processed is stabilized at a second temperature set value,
Heating the inside of the reaction vessel to the processing temperature or performing a heat treatment on the object at that temperature without raising the temperature;
A heat treatment method comprising: 14. The heat treatment method according to claim 13, wherein the temperature set value increases from the first temperature set value to the second temperature set value before or after the loading of the object to be processed. . 15. The heat treatment method according to claim 14, wherein the temperature set value gradually increases from the first temperature set value toward the second temperature set value. 16. An object to be processed is carried into a reaction vessel, and a heating means is controlled based on a comparison result between a set temperature value and a detected temperature value in the reaction vessel to heat the object to perform heat treatment. In the performing method, the temperature set value is set to a third temperature set value higher than the second temperature set value corresponding to the target temperature at the time of carrying in the object, and the object is carried into the reaction vessel. And a step of setting the temperature set value to a second temperature set value lower than the third temperature set value. After the object to be processed is stabilized at the second temperature set value, the inside of the reaction vessel is A step of performing a heat treatment on the object to be processed at a temperature with or without increasing the temperature to the processing temperature. 17. The heat treatment apparatus according to claim 16, wherein the temperature set value decreases from the third temperature set value to the second temperature set value before or after the completion of the loading of the object to be processed. . 18. The heat treatment apparatus according to claim 17, wherein the temperature set value gradually decreases from the third temperature set value toward the second temperature set value. 19. An object to be processed is carried into a reaction vessel, and heating means is controlled based on a comparison result between a set temperature value and a detected temperature value in the reaction vessel to heat the object to perform heat treatment. In the performing method, the temperature set value is set to a first temperature set value lower than a second temperature set value corresponding to a target temperature at the time of carrying in the object, and the object is carried into the reaction vessel. Setting the temperature set value to a third temperature set value higher than the second temperature set value; and then setting the temperature set value to a second temperature set value from the third temperature set value. After the object to be processed is stabilized at the second temperature set value, heat treatment is performed on the object at that temperature with or without raising the temperature in the reaction vessel to the processing temperature. A heat treatment method. 20. The temperature set value instantaneously rises from the first temperature set value to the third temperature set value before or after the completion of the loading of the object to be processed, and then from the third temperature set value to the second temperature set value. 20. The heat treatment method according to claim 19, wherein the temperature gradually decreases toward the temperature set value.