JPH1025577A - Film processing equipment - Google Patents

Abstract

(57) [Problem] To provide a film forming apparatus capable of rapidly stabilizing the temperature of an object to be processed even if film formation adheres to an unnecessary portion. SOLUTION: A processing container 6 composed of an inner cylinder 2 and an outer cylinder 4 arranged concentrically outside the inner cylinder 2 and a plurality of workpieces W are placed and accommodated in the processing vessel in a removable manner. A supporting boat 14, a heating means 8 concentrically arranged outside the processing vessel, a heater temperature detecting means 28 arranged near the heating means, and the outer cylinder housed in a sealed protective tube. Control temperature detecting means 32A to 32E provided between the control unit 4 and the inner cylinder; and a control unit 4 for controlling power supplied to the heating means based on a detection value of the control temperature detecting means.
And a temperature suppressing tube 50 made of a transparent heat-resistant material, the inside of which can be ventilated, provided outside the protective tube. To be configured. As a result, an unnecessary film is adhered also to the temperature suppression pipe, and the rate of temperature rise of the control temperature detecting means in this portion is reduced, and the calorific value of the heating means is increased accordingly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a film forming apparatus for forming a film on an object to be processed such as a semiconductor wafer.

[0002]

2. Description of the Related Art In general, in order to manufacture a semiconductor device, a film formation process and a pattern etching process are repeatedly performed on a semiconductor wafer to manufacture a desired device. The specifications are becoming stricter with the integration. With regard to film formation, vertical batch processing furnaces have become the mainstream because a large number of wafers can be processed at one time, and wafer temperature control during processing is especially important to efficiently form good quality film formation. It is.

[0003] For example, in the case of a double tube vertical furnace, a thermocouple for heater is provided on the heating furnace side, and a control temperature is provided between the inner cylinder and the outer cylinder of the processing vessel. A thermocouple,
The temperature inside the container is detected by a thermocouple for control, and the power supplied to the heater is controlled based on the detected value. In this case, since the heat dose decreases each time the light passes through the outer cylinder and the inner cylinder made of quartz, a thermocouple for control is provided inside the inner cylinder in order to accurately detect the wafer temperature. Good, but metals such as thermocouples cannot be installed inside the inner cylinder to prevent metal contamination etc. of the wafer,
As described above, a thermocouple for control is provided between the inner cylinder and the outer cylinder as a second best measure to detect the wafer temperature indirectly.

In this case, a slight temperature difference between the actual temperature of the wafer and the detected temperature of the control thermocouple disposed between the inner cylinder and the outer cylinder, for example, a temperature difference of about several tens of degrees Celsius. Prior to the process, for example, a table thermocouple expected to more accurately detect the wafer temperature inside the inner cylinder at the assembly factory level is placed before the process, and this table thermocouple and The temperature correlation between the control thermocouple and the heater thermocouple is previously tabulated. The actual process is performed with the above-described table thermocouple removed, and the heater is supplied to the heater based on the detection value of the control thermocouple disposed between the inner cylinder and the outer cylinder as described above. The power is controlled.

Here, a conventional vertical film forming apparatus will be described. FIG. 9 is a configuration diagram showing a conventional vertical film forming apparatus. This film forming apparatus has a processing vessel 6 having a double tube structure composed of an inner cylinder 2 made of quartz and an outer cylinder 4 made of quartz concentrically arranged outside the inner cylinder 2. And the like, and a heating furnace 12 provided with a heat insulating material 10. The lower end of the processing container 6 is open,
A support boat 14 on which a number of semiconductor wafers W as objects to be processed are mounted from below is detachably inserted so as to be able to move up and down. The support boat 14 is mounted on a rotary table 18 via a heat insulating tube 16 made of quartz, and the rotary table 18 is attached to an upper end of a rotary shaft 22. The rotation shaft 22 penetrates a lid 20 that allows the lower end opening side of the processing vessel 6 to be opened and sealed freely and airtightly and rotatably. When the support boat 14 moves up and down, the lid 20 also moves up and down integrally. Is done.

A processing gas introduction nozzle 24 for introducing a processing gas for film formation into the inner cylinder 2 is provided at a lower side of the processing vessel 6, and an exhaust connected to a vacuum exhaust system (not shown) is provided at a lower side of the outer cylinder 4. A mouth 26 is provided. The heating furnace 12 is divided into a plurality of, for example, five zones in the vertical direction, and at least one heater temperature detecting means, for example, a thermocouple is provided for each zone in order to perform temperature control independently for each zone. 2
8A to 28E, and a control temperature detecting means housed in a quartz protection tube 30 having a diameter of about several mm which is sealed between the inner cylinder 2 and the outer cylinder 4 corresponding to this zone. For example, thermocouples 32A to 32E are provided.

In the apparatus configured as described above, focusing on the temperature distribution, it is natural that the temperature of the heating means 8 as the heat source is the highest, and the temperature increases as it goes inside the processing vessel 6. Is generally reduced and a temperature gradient is formed. For example, when it is desired to set the processing temperature of the wafer W located at the center of the container to 600 ° C., the temperature of the control thermocouple 32 outside the temperature is about 630 ° C.
The temperature of the heater thermocouple 28 on the outer side is 660
About ℃. In this case, the correlation between the desired wafer temperature, and the temperature of the control thermocouple 32 and the temperature of the heater thermocouple 28 at that time is slightly different for each processing apparatus. At the factory level or the like, table thermocouples 34A to 34E are arranged between the inner cylinder 2 and the support boat 14 in correspondence with the zones, and the table thermocouples 34, the control thermocouples 32, and the heater thermocouples are provided. The temperature correlation with the temperature 28 is obtained for each zone and for each of a plurality of desired wafer temperatures, and is tabulated in advance. In this case, the detected temperature of the table thermocouple 34 closest to the wafer is regarded as the wafer temperature.

[0008] Such a table is stored in a control computer, and the actual film forming process is performed with the table thermocouple 34 removed, and based on the temperature detected by the control thermocouple 32. The power supply to the heater is controlled by, for example, PID control while referring to the table. For example, when a film is to be formed at a temperature of 600 ° C., the temperature of the wafer cannot be directly detected.
The power supply to the heater 8 is controlled so as to maintain. Such temperature control is performed similarly when the temperature of the processing container 6 is raised from idling to a predetermined process temperature, and the detected temperature value of the control thermocouple 32 is always used as a reference.

[0009]

By the way, in order to raise the temperature of a wafer to a predetermined temperature after introducing a normal-temperature wafer into the processing chamber, the temperature is raised as quickly as possible in order to improve the processing efficiency. It is necessary to stabilize the whole at the process temperature with high accuracy. In this case, of the five zones divided vertically, the zone located at the bottom is
Since the heat retaining cylinder 16 having a larger heat capacity than the other parts is located and this part is finally accommodated in the processing container 6, the lowest zone is heated most slowly. Will determine the time to temperature stabilization. Therefore, how to stabilize the temperature of the lowermost zone quickly is an important point in improving the processing efficiency.

In general, when the film forming process by CVD or the like is repeatedly performed, the portions in contact with the processing gas, ie, the inner and outer wall surfaces of the inner tube 2, the inner wall surface of the outer tube 4, and the outer wall surface of the protection tube 30 are slightly increased. For example, a polysilicon film or Si ₃
A film such as N ₄ tends to adhere. FIG. 10 is an enlarged view of a portion surrounded by a broken line A in FIG.
Unnecessary film formations 36A and 36B adhere to the inner and outer wall surfaces, and unnecessary film formation 36C adheres to the inner wall surface of the cylindrical outer cylinder 4,
Unnecessary film formation 36D on the outer wall surface of sealed thin tubular protective tube 30
Is attached.

This film has a lower thermal emissivity (absorptivity) and a higher thermal reflectivity than the quartz constituting the processing vessel 6, so that heat from the heater 8 is directed toward the center of the processing vessel 6. Difficult to reach. For example, taking the thermocouple in the lowermost zone shown in FIG. 10 as an example, the temperature gradient between the control thermocouple 32E and the wafer temperature (the portion of the table thermocouple 34E) during the temperature rise causes the process. It means that it increases each time a film is repeatedly deposited. That is, the film forming through which the heat ray is transmitted when the table thermocouple 34E faces from the heater 8 is formed by the film forming 36C attached to the inner wall surface of the outer cylinder 4 and the two film forming 36A attached to both surfaces of the inner cylinder 2; 36B, which is a total of three, and the thickness of these films increases, so that it is difficult for heat to be transmitted to the center of the container. The protective tube 30 has a diameter of several meters.
m, so that the film 36D adhered to this has nothing to do with electric heating to the center of the container. On the other hand, when the control thermocouple 32 </ b> E faces from the heater 8, the film through which the heat rays pass is formed by the film 36 </ b> C attached to the inner wall surface of the outer cylinder 4 and the film 36 </ b> D attached to the protection tube 30. There are two in total. Therefore, the heat ray reaching the wafer passes through one additional film formation, and accordingly, the rate of temperature increase of the actual temperature of the wafer portion is higher than that of the corresponding control thermocouple 32E. It will gradually become slower.

Also in this case, the temperature control in the furnace is
When assembling the equipment, it is performed based on the temperature correlation table obtained before performing the actual process.
There has been a problem that the followability of the actual wafer temperature gradually deteriorates, and more time is spent until the wafer temperature is actually stabilized.

FIG. 11 shows an unnecessary polysilicon film having a thickness of 5 μm.
m is a graph showing a temperature profile when about m is attached, in which R is a control thermocouple in the lowermost zone, S
Represents the temperature change of the lowermost zone heater thermocouple, and P represents the temperature change of the lowermost zone table thermocouple (attached for the test). Here, each time the film forming process is repeated, the film thickness of the film deposited on the unnecessary portion increases, so that the temperature rising rate of the temperature of the table thermocouple (which can be regarded as the actual temperature of the wafer) is one point. As indicated by the dashed line, the time becomes gradually slower, and the time from when the normal temperature wafer is loaded into the container until the temperature is stabilized at 600 ° C. becomes gradually longer. That is, even if the detection temperature of the control thermocouple reaches the stable region early, the actual temperature of the wafer is far from the stable region, and as a result of the detected temperature entering the stable region, the heater power is reduced. As a result, it takes a considerable amount of time thereafter for the wafer temperature to enter the stable region. In the illustrated example, for example, when a polysilicon film having a thickness of 5 μm adheres to an unnecessary portion, it takes 111.2 minutes to stabilize the temperature.

To solve such a problem, PID
When compensating for the degradation of the heating rate by changing the control parameters in the middle, or when taking a table of temperature correlation,
It is also possible to attach a small amount of film to the inner cylinder, outer cylinder, and protection tube.However, there is a limit to correcting the parameters by software. However, the above-mentioned problem cannot be solved sufficiently. The present invention has been devised in view of the above problems and effectively solving them. An object of the present invention is to provide a film forming apparatus capable of rapidly stabilizing the temperature of an object to be processed even if a film is attached to an unnecessary portion.

[0015]

The inventor of the present invention has conducted intensive studies on the temperature control of the film forming process. As a result, the PID control is performed by intentionally deteriorating the electric heating efficiency of the heating wire from the heater to the control thermocouple. The present invention has been made based on the finding that an increase in the power supplied to the heater can increase the rate of temperature rise of the object to be processed. The present invention is a processing vessel comprising an inner cylinder and an outer cylinder arranged concentrically on the outside thereof, and a support boat on which a plurality of objects to be processed are placed and removably housed in the processing vessel, Heating means arranged concentrically outside the processing vessel, heater temperature detecting means arranged near the heating means, and housed in a sealed protective tube between the outer cylinder and the inner cylinder. It has a control temperature detecting means installed, and a control unit for controlling power supplied to the heating means based on a detection value of the control temperature detecting means, and forms a film on the object by a processing gas. In the film forming apparatus to be applied, a temperature suppressing tube made of a transparent heat-resistant material and having a permeable inside is provided outside the protective tube.

By repeatedly performing the film forming process by the apparatus as described above, the heat reflectance is large on both surfaces of the inner cylinder of the processing container, the inner wall surface of the outer cylinder, the outer surface of the protection tube, and the inner and outer surfaces of the temperature control tube. Unnecessary film formation gradually adheres. Then, the number of unnecessary film formations between the heating means and the control temperature detecting means is increased, and the number of unnecessary film formations between the heating means and the object is increased. Since the temperature rising rate of the temperature detecting means decreases, the control unit that controls the power supply to the heating means based on the detected value is reduced by the slower the temperature rising rate of the temperature detected by the control temperature detecting means. It operates to increase the supply power.

Therefore, the object to be processed is quickly heated, and quickly reaches the temperature stable region. That is, by providing a temperature suppression tube and intentionally suppressing the amount of heat supplied to the control temperature detecting means by using unnecessary film deposition attached thereto, the amount of power supplied to the heating means is reduced accordingly. The temperature of the object to be processed is quickly raised to a temperature stable region. In this case, the processing container is divided into a plurality of zones in the vertical direction, and the temperature is controlled independently and independently for each zone. However, the processing container is located at the lowermost zone that controls the time until the temperature of the object is stabilized. At least a temperature suppression pipe is provided corresponding to the control temperature detecting means. This temperature suppression tube is made of, for example, a quartz tube, and is fixed to the outer wall of the protection tube by welding. Further, each of the temperature detecting means may be constituted by a thermocouple.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a film forming apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. 1 is a block diagram showing a film forming apparatus according to the present invention, FIG. 2 is an enlarged view of a main part in FIG. 1, FIG. 3 is a partial plan view of the main part shown in FIG. 2, and FIG. It is a perspective view showing a control pipe. The same parts as those of the conventional device will be described with the same reference numerals.

Here, a vertical heat treatment apparatus by CVD will be described as an example of a film forming apparatus. As shown in the figure, this heat treatment apparatus has a processing vessel 6 having a double tube structure composed of a cylindrical inner cylinder 2 made of quartz and an outer cylinder 4 made of quartz arranged concentrically outside the inner cylinder 2. The outside thereof is covered with a heating means 12 such as a heating heater and a heating furnace 12 having a heat insulating material 10. The heating means 8 is provided on the entire inner surface of the heat insulating material 10. The lower end of the processing vessel 6 is supported by a cylindrical manifold 38 made of, for example, stainless steel, and a quartz support boat on which a plurality of semiconductor wafers W as processing objects are mounted from below the manifold 38. 14 is removably insertable and removable.

The support boat 14 is made of a heat insulating tube 1 made of quartz.
The rotary table 18 is mounted on a rotary table 18 via a rotary shaft 6. The rotary table 18 is supported on a rotary shaft 22 that penetrates a lid 20 that opens and closes a lower end opening of a manifold 38. For example, a magnetic fluid seal 40 is interposed in the penetrating portion of the rotating shaft 22, and rotatably supports the rotating shaft 22 while hermetically sealing it. In addition, a seal member 42 made of, for example, an O-ring is provided between the periphery of the lid 20 and the lower end of the manifold 38 to maintain the sealing property in the container.

The rotating shaft 22 is attached to the tip of an arm 46 supported by a lifting mechanism 44 such as a boat elevator, so that the supporting boat 14 and the lid 20 can be moved up and down integrally. I have. A processing gas introduction nozzle 24 for introducing a processing gas for film formation into the inner cylinder 2 and an exhaust port 26 for discharging the atmosphere in the container from between the inner cylinder 2 and the outer cylinder 4 are provided on the side of the manifold 38. A vacuum exhaust system provided with a vacuum pump or the like (not shown) is connected to the exhaust port 26.

On the other hand, such a heating furnace 12 is vertically divided into a plurality of, for example, five zones 48A to 48E in order to control the entire temperature with high accuracy. The heaters are also divided into five groups of 8A to 8E. And the heaters 8A to 8E of each zone
, For example, heater thermocouples 28A to 28A as heater temperature detecting means for detecting the heater temperature.
E is provided.

Also, between the inner cylinder 2 and the outer cylinder 4, here, five control thermocouples 32 A to 32 E as control temperature detecting means corresponding to each zone are provided with one sealed quartz quartz. The lower end of the protective tube 30 is bent and supported in a gas-tight manner through the manifold 38. The detected values of the respective thermocouples are input to a control unit 49 composed of, for example, a microcomputer or the like, and the power supplied to the heaters 8A to 8E in each zone is individually and independently determined during the process based on the detected values. Control. The protection tube 30 is provided with a temperature suppression tube 50 which is a feature of the present invention. Specifically, this temperature suppression tube 5
0 is the lowermost end, which does not cover the entire protective tube 30 but controls the speed until the temperature of the object to be processed is stabilized until the temperature rises slowest due to the location of the heat retaining tube 16 having a large heat capacity. Is provided so as to cover at least a portion of the control thermocouple 32E located in the zone 48E. Specifically, as shown in FIGS. 2 to 4, the temperature suppressing tube 50 has a length L.
Is made of a quartz tube having a diameter of about 30 mm, and its inner diameter R1 is 11 mm, which is slightly larger than that of the protective tube 30 having an outer diameter of about 9 mm.
The thickness is set to about 1 mm.

The temperature control pipe 50 is welded and fixed to the outer wall of the protection pipe 30 by partial welding 52 at the upper and lower ends thereof, and the processing gas being exhausted flows into the temperature control pipe 50. Thus, an unnecessary film can be formed on the tube wall. By providing the temperature suppression tube 50 in this manner, an unnecessary polysilicon film, nitride film, or the like having a higher reflectance than quartz adheres to the inner and outer surfaces during the film forming process, and the control thermoelectric element located inside the film is used. Vs 32E
Can be intentionally suppressed. Needless to say, the length L and the inner diameter R1 of the temperature suppression tube 50 are not limited to the above values. Also, the method of holding the temperature suppression tube 50 is not based on welding as described above, and the length of the suppression tube 50 may be increased to be supported by the bent portion of the protection tube 30. Even temperature suppression tube 50
Is set in a state in which the processing gas can flow.

Next, a film forming process using the apparatus configured as described above will be described. First, prior to the actual execution of the film forming process, the temperature profile in the radial direction of the processing container is tabulated in advance for each zone. This temperature profile is performed, for example, when the apparatus is assembled, or when a very small unnecessary film is deposited on the inner wall of the container after performing a film forming process on a trial basis.
When this table is created, the table thermocouples 34A to 34A to
34E is placed inside the inner tube 2 in a state of being housed in the quartz tube 56. The table thermocouples 34A to 34E are:
Since it is as close as possible to the wafer W, the detected value can be regarded as the actual wafer temperature in that zone.

In this state, when the detection values of the table thermocouples 34A to 34E reach various process temperatures, the corresponding control thermocouples 32A to 32E correspond to the process temperatures.
The detected values of the heater thermocouples 28A to 28E are detected for each zone and are tabulated. For example, when the process temperature is desired to be 600 ° C., the table thermocouples 34A to 34A
The detection values of the control thermocouple and the heater thermocouple when 34E detects 600 ° C. are tabulated. Normally, the temperature is highest in the vicinity of the heater. At this time, the detected value decreases as the temperature of the heater thermocouple approaches 660 ° C. and the temperature of the control thermocouple approaches 630 ° C. Therefore, at the time of actual processing, since the table thermocouples 34A to 34E which are obstacles are removed, when processing a wafer at a process temperature of 600 ° C., the control unit 49 controls the control thermocouples 32A to 32E. 32E is 63
The electric power supplied to the heater is controlled so as to maintain 0 ° C.

In this case, the control unit controls the supplied power by well-known PID control, and naturally operates to increase the supplied power as the temperature deviation is larger and to narrow the supplied power as the deviation is smaller. . Therefore, the control thermocouple 32A
In the case where the rate of temperature increase of .about.32E is slow and the deviation from the target temperature value is not easily reduced, the power supplied to the heater is increased and the operation is performed so as to generate more heat. In the present invention, by utilizing this development, the rate of temperature rise of the control thermocouple is intentionally reduced to induce more heat generation. When the temperature profile table is completed in this way, the table is stored in the control unit 49 and is referred to in the subsequent actual film forming process.

Next, when the actual film forming process is performed on the wafer, the table thermocouples 34A to 34E which become obstacles are removed from the processing container as described above. First, when the wafer is unloaded and the processing apparatus is in a standby state, the processing container 6 is maintained at a process temperature, for example, 600 ° C. or lower, and supports a large number of wafers W at a normal temperature. The container is sealed by closing the opening at the lower end of the manifold 38 with the lid 20 while the container is placed in the processing container 6 and loaded into the processing container 6 from below. Then, while maintaining the inside of the processing container 6 at a predetermined process pressure, the process waits until the wafer temperature rises and stabilizes at the predetermined process temperature. 6 is introduced. The determination as to whether or not the temperature of the wafer is stable is made based on whether or not the temperature in the lowermost zone where the heat retaining cylinder 16 having a large heat capacity is located is stable. After the processing gas is introduced from the processing gas introduction nozzle 24 to the bottom of the inner cylinder 2, the film forming reaction proceeds while contacting the wafer W being rotated therein, and rises. The gas flows down the gap between the outer cylinder 4 and is discharged from the container through the exhaust port 26. Temperature control during the process is performed by controlling thermocouples 32A to 3A.
The power supply to the heaters 8A to 8E is controlled by PID control so that the detected value in 2E becomes the temperature of the control thermocouple on the table corresponding to the process temperature at that time.

The flow of the film forming process has been described above. If such a process is repeated, unnecessary film forming, for example, poly film, is performed on the wall surface of the quartz member that comes into contact with the processing gas in the flow direction. It is unavoidable that a silicon film is formed little by little. Unnecessary film formation includes the inner and outer surfaces of the inner tube 2, the inner surface of the outer tube 4, and the control thermocouples 32A to 32A.
It adheres to the outer surface of the protection tube 30 accommodating 32E, the inner and outer surfaces of the temperature suppression tube 50, and the like. FIGS. 5 and 6 show the state of adhesion of unnecessary film formation at that time. The film formation 36A adheres to the inner surface of the inner cylinder 2 and the film formation 36B adheres to the outer surface thereof. A film 36C adheres to the inner surface of the outer cylinder 4, and a film 36D adheres to the outer surface of the protective tube 30. Up to this point, it is the same as the conventional apparatus shown in FIG. Further, in the present invention, the film 36E and the film 36F adhere to the inner surface and the outer surface of the temperature suppression tube 50 surrounding the control thermocouple 32E corresponding to the lowermost zone, respectively. These films usually have a thickness of about several μm, depending on the number of processes.

As described above, these unnecessary films generally have a low absorptivity to heat rays and a high reflectivity. Therefore, as the film thickness grows, the temperature profile initially determined gradually deteriorates, and It is no longer a table that reflects the temperature profile. As described with reference to FIG. 11, for example, in the conventional apparatus, when the wafer is faced from the heater 8, the heat rays are divided into three films 36 </ b> A, 36 </ b> A.
B, 36C, from the heater 8 to the control thermocouple 3
At the time of approaching 2, since the heat ray passes through the two film formations 36C and 36D, the control thermocouple 32 enters the temperature stable region earlier due to the difference in the number of film formations transmitted by the heat ray. However, the actual temperature of the wafer has not risen to the temperature determined by the temperature profile,
It has become increasingly necessary for the wafer temperature to gradually enter the stable region.

On the other hand, in the present invention, by providing the temperature suppression tube 50 and attaching an unnecessary film to the inner and outer surfaces thereof, the control thermocouple 32E in the lowermost zone faces from the heater 8E. At that time, the heat rays are deposited on the outer cylinder 4
6C, the film formation 36D of the protection tube 30 and the temperature suppression tube 50
Since the film passes through the two film formations 36E and 36F on the inner and outer surfaces, a total of four film formations are passed, and the number of film formations from the heater to the wafer is increased by one from three (the same as the conventional case). This means that even if the same heating value is emitted from the heater 8E, the temperature rise of the control thermocouple 32E is suppressed. Under the PID control, the larger the deviation between the detected temperature value and the target temperature value is, the more the amount of heat generated per unit time is released, even if there is an upper limit, so that the temperature difference is reduced quickly. As a result, as described above, as a result of suppressing the rate of temperature rise of the control thermocouple 32E, the control unit 48 increases the power supply to the heater 8E so as to emit more heat. As a result, the actual temperature of the wafer W is quickly heated to the temperature stable region even though an unnecessary film is formed due to the repetition of the process, and the temperature rising rate is almost lower than the initial temperature. And the rate of temperature rise can be kept high.

As described above, by providing the temperature suppression tube 50 and deliberately reducing the thermal responsiveness of the control thermocouple 32E in the lowermost zone, as a result, the rate of temperature rise of the wafer itself can be maintained high. And the temperature can be quickly raised to the heat stable region. FIG. 7 is a graph schematically showing the temperature rising rate at this time, and shows the detected value of the heater thermocouple, the detected value of the control thermocouple, and the wafer temperature in order from the top. In the figure, the solid line indicates the conventional temperature curve, and the dashed line indicates the temperature curve of the present invention. When a normal-temperature wafer is loaded into the container, the detection value of the control thermocouple 32E temporarily decreases, but the control unit 48, which detects this decrease, increases the power supplied to the heater and increases the control thermoelectric power. The detection value of pair 32E is about to be immediately drawn into the temperature stable region. Accordingly, the wafer temperature also becomes, for example, 600
The temperature rises rapidly to ° C.

Here, when the temperature suppressing tube 50 is provided as in the present invention, the unnecessary film formation formed on the temperature suppressing tube 50 reduces the rate of temperature rise of the control thermocouple 32E after the wafer is loaded. On the other hand, more electric power is supplied to the heater controlled under the PID control, and the heater thermocouple 2 is controlled.
The temperature of 8E rises, and similarly, the temperature rise rate of the wafer W also rises, and the wafer W quickly enters the temperature stable region. Here, the temperature stable region refers to a state where the detected value falls within a range of ± 1 ° C. of the target temperature. FIG. 8 is a graph showing a temperature curve in the lowermost zone using an actual apparatus, which is performed in a state where a polysilicon film having a thickness of about 5 μm is formed as unnecessary film formation. The target temperature value of the wafer portion is set to 600 ° C., and from the top of the graph, the detected value of the heater thermocouple, the detected value of the control thermocouple, and the table thermocouple (wafer temperature) provided for the experiment. 3) shows the respective temperature curves of the detected values.

According to this, it takes 89 minutes for the detected value of the table thermocouple, that is, the actual wafer temperature to stabilize. In the case of the conventional apparatus shown in FIG.
In contrast to 2 minutes, in the present invention, it is found that the temperature can be raised to the temperature stable region as early as about 22 minutes. In the above embodiment, the temperature suppression tube is provided only in the portion of the protection tube 30. However, the temperature suppression tube is not limited to this, and may be provided over the entire protection tube. In addition, although a semiconductor wafer has been described as an example of an object to be processed, it is needless to say that the present invention can be applied to film formation on another substrate such as an LCD. Furthermore, although the vertical type film forming apparatus has been described here, the present invention can also be applied to a horizontal type film forming apparatus.

[0035]

As described above, according to the film forming apparatus of the present invention, the following excellent effects can be obtained. A temperature suppression tube was provided in the protective tube containing the control temperature detection means, and the rate of temperature rise of the temperature detection means was suppressed by unnecessary film formation attached to the protection tube.
To that extent, the amount of heat radiation from the heating means can be increased, and the rate of temperature increase of the actual temperature of the object to be processed can be maintained high despite unnecessary film deposition. Therefore, the waiting time until the temperature of the object to be processed is stabilized can be greatly shortened, and not only the throughput can be improved, but also the non-uniformity of the film thickness caused by performing the film forming process when the temperature is unstable can be suppressed. . In particular, by providing the temperature suppression tube in the control temperature detecting means corresponding to the lowermost zone that controls the speed up to the temperature stabilization, the above effect can be exhibited with a simple structure. Further, this temperature suppressing tube can be easily attached to and fixed to the protective tube by welding.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a film forming apparatus according to the present invention.

FIG. 2 is an enlarged view of a main part in FIG.

FIG. 3 is a partial plan view of a main part shown in FIG. 2;

FIG. 4 is a perspective view showing a protection tube and a temperature suppression tube.

FIG. 5 is a partially enlarged view showing a state when an unnecessary film is attached to the portion shown in FIG. 2;

FIG. 6 is a partial plan view of the portion shown in FIG. 5;

FIG. 7 is a graph schematically showing a heating rate according to the present invention.

FIG. 8 is a graph showing a temperature rise rate when the temperature is raised using an actual apparatus.

FIG. 9 is a configuration diagram illustrating a conventional film forming apparatus.

FIG. 10 is a partially enlarged view showing a part when an unnecessary film is adhered in the apparatus shown in FIG. 9;

FIG. 11 is a graph showing a temperature rising rate of a conventional film forming apparatus.

[Explanation of symbols]

 2 Inner tube 4 Outer tube 6 Processing vessel 8 Heating means (Heating heater) 14 Support boat 16 Protective cylinder 28 Heater temperature detecting means (thermocouple) 30 Protective tube 32A-32E Control temperature detecting means (thermocouple) 34A-34E Table thermocouples 36A to 36F Unnecessary film formation 48 Zone 49 Control unit 50 Temperature suppression tube 52 Welding W Semiconductor wafer (workpiece)

Claims (5)

[Claims] 1. A processing vessel comprising an inner cylinder and an outer cylinder arranged concentrically outside the inner cylinder, a support boat on which a plurality of objects to be processed are placed and accommodated in the processing vessel so as to be insertable and removable. Heating means arranged concentrically outside the processing vessel,
A heater temperature detecting means disposed in the vicinity of the heating means; a control temperature detecting means housed in a sealed protective tube and disposed between the outer cylinder and the inner cylinder; and a control temperature detecting means. A control unit for controlling the power supplied to the heating means based on the detected value of, in a film forming processing apparatus for forming a film on the object to be processed by a processing gas, the inside of the protective tube, A film forming apparatus characterized in that a temperature suppressing tube made of a transparent heat-resistant material is provided so as to allow ventilation. 2. The heating means is divided into a plurality of zones in the height direction, and a plurality of the heater temperature detecting means and the control temperature detecting means are provided corresponding to the zones. The film forming apparatus according to claim 1, wherein: 3. The control device according to claim 2, wherein the temperature suppression pipe is provided in correspondence with the control temperature detecting means corresponding to at least a zone located at a lowermost end of the plurality of zones. The film forming apparatus according to any one of the preceding claims. 4. A film forming apparatus according to claim 1, wherein each of said temperature detecting means comprises a thermocouple. 5. The film forming apparatus according to claim 1, wherein the temperature suppression tube is formed of a quartz tube, and is fixed to an outer wall of the protection tube by welding.