JP2020088322A - Epitaxial wafer manufacturing method and device - Google Patents

Abstract

To provide an epitaxial wafer manufacturing method and device capable of stabilizing the quality of the epitaxial wafer when performing multi-deposition processing.SOLUTION: An epitaxial wafer manufacturing device comprises: a sheet-type epitaxial growth furnace 1 including a quartz upper dome 12; a susceptor 16 in which a wafer W is placed; a gas supply system 3 which supplies a reaction gas or a cleaning gas into a chamber 11 of the epitaxial growth furnace; a heater 15 which heats the inside of the chamber; an infrared radiation temperature sensor 4 which detects a temperature on a surface of the wafer; and a controller 5 which controls output of the heater in such a manner that the detected temperature is within a predetermined temperature range, and controls the gas supply system. The controller sets a standby time from end of cleaning processing to first throwing of the wafer into the chamber to such a time that a variation coefficient of the output of the heater is settled within a predetermined range, and inhibits the first throwing of the wafer until a time from the end of the cleaning processing reaches the standby time.SELECTED DRAWING: Figure 1

Description

The present invention relates to an epitaxial wafer manufacturing method and apparatus.

In the production of silicon epitaxial wafers, a single-wafer type epitaxial growth apparatus that is applicable to a large-diameter silicon wafer is used in addition to a batch-type epitaxial growth apparatus that simultaneously performs epitaxial growth processing on a plurality of silicon wafers. This type of single-wafer type epitaxial growth apparatus heats and rotates a wafer placed on a susceptor in a chamber of an epitaxial growth furnace to a high temperature, introduces a silicon reaction gas by hydrogen carriers, and deposits a silicon thin film on the surface of the wafer. Grow. As a reaction gas for silicon epitaxial growth, monosilane gas (SiH ₄ ) or silane chloride gas (SiH ₂ Cl ₂ , SiHCl ₃ ) or the like is used.

In this reaction process, a product of a material gas such as amorphous silicon or a silane chloride polymer adheres and deposits on the wall surface in the chamber, the susceptor, or the like. If this deposit is peeled off during the epitaxial growth process and adheres to the wafer, it may be mixed in the thin film of the wafer as an impurity to deteriorate the quality of the wafer. Therefore, a cleaning gas such as hydrogen chloride gas or chlorine trifluoride gas is supplied into the chamber during the sequential epitaxial growth process of the wafer to perform a cleaning process for removing deposits. Since the productivity decreases if the cleaning process is performed for each epitaxial growth process of one wafer, the cleaning process in the chamber is performed once after the epitaxial growth processes are continuously performed a plurality of times. A treatment method may be performed (Patent Document 1).

JP, 2015-26776, A

However, based on the device structure, the quality of the silicon epitaxial thin film on the surface of the silicon wafer has also been improved and the accuracy has been improved. When the above multi-deposition treatment method is performed, the first epitaxial growth after the cleaning treatment in the chamber is performed. There is a problem that the quality (for example, film thickness) of the epitaxial layer by the treatment and the quality (for example, film thickness) of the epitaxial layer by the second and subsequent epitaxial growth treatments vary, and the quality is not stable.

The problem to be solved by the present invention is to stabilize the quality of an epitaxial wafer when performing a multi-deposition process in which a cleaning process in a chamber is performed once after continuously performing an epitaxial growth process a plurality of times, and It is an object of the present invention to provide a method and an apparatus for manufacturing an epitaxial wafer, which can keep equipment conditions such as epitaxial growth processing conditions constant.

The present invention puts wafers one by one into a chamber of an epitaxial growth furnace,
While measuring the temperature of the surface of the wafer by a non-contact temperature sensor, controlling the output of the heater to heat the inside of the chamber so that the detected temperature is within a predetermined temperature range,
A method of manufacturing an epitaxial wafer, wherein an epitaxial layer is vapor-phase grown on a surface of a wafer while supplying a reaction gas into the chamber,
In a method of manufacturing an epitaxial wafer, after performing a plurality of epitaxial growth treatments in succession, a cleaning treatment for removing deposits deposited in the chamber is performed once,
The waiting time from the end of the cleaning process to the loading of the first wafer into the chamber is such that the fluctuation rate of the output of the heater during the multiple epitaxial growth processes falls within a predetermined range. The above problem is solved by an epitaxial wafer manufacturing method in which the time is set and an epitaxial growth process is performed.

In the present invention, the standby time is the output of the heater when the first epitaxial growth process is performed after the cleaning process is finished, and the heater when the second and subsequent epitaxial growth processes are performed. It is more preferable that the variation rate with the output of is within a range of ±0.5%.

In the present invention, a quartz upper dome is provided in the upper part of the epitaxial growth furnace, and the non-contact temperature sensor detects the temperature of the surface of the wafer from outside the epitaxial growth furnace through the quartz dome. Can be configured to.

In the present invention, the non-contact temperature sensor is, for example, an infrared radiation temperature sensor.

Further, the present invention is a single-wafer type epitaxial growth furnace having at least a quartz upper dome,
A susceptor for mounting a wafer,
A gas supply system for supplying a reaction gas or a cleaning gas into the chamber of the epitaxial growth furnace;
A heater for heating the inside of the chamber,
An infrared radiation temperature sensor for detecting the temperature of the surface of the wafer from outside the chamber through the quartz upper dome;
While controlling the output of the heater so that the temperature detected by the infrared radiation temperature sensor falls within a predetermined temperature range, and a controller that controls the gas supply system, in an epitaxial wafer manufacturing apparatus,
The controller is
The gas supply system is controlled so that the cleaning process for removing the deposit accumulated in the chamber is performed once after the epitaxial growth process is continuously performed a plurality of times,
The waiting time from the end of the cleaning process to the loading of the first wafer into the chamber is such that the fluctuation rate of the output of the heater during the plurality of epitaxial growth processes falls within a predetermined range. Set in time,
Until the time from the end of the cleaning process reaches the waiting time, the first wafer loading is prohibited, and if the time from the end of the cleaning process exceeds the waiting time, The above problem is also solved by an epitaxial wafer manufacturing apparatus that permits the first wafer loading.

According to the present invention, the waiting time from the end of the cleaning process until the first wafer is loaded into the chamber is determined by the fluctuation rate of the output of the heater when the epitaxial growth process is performed a plurality of times within a predetermined range. Since the time is set to the start time, the quality of the epitaxial wafer can be stabilized and the equipment conditions such as the epitaxial growth processing conditions can be kept constant when performing the multi-depot processing.

It is a block diagram showing one embodiment of a manufacturing device of an epitaxial wafer of the present invention. It is a graph which shows the temperature transition of the processing process (multi-depot processing) of one embodiment of the manufacturing method of the epitaxial wafer of the present invention. It is a graph which shows the result of the confirmation experiment which measured the relative film thickness of the epitaxial layer when standby time was made into 0 second-300 second. It is a graph which shows the result of the confirmation experiment which measured the relative temperature of the silicon wafer surface when standby time was made into 0 second-300 second. It is a graph which shows the result of the confirmation experiment which measured the relative output of the halogen lamp when standby time was made into 0 second-300 second. It is a graph which shows the result of the confirmation experiment which measured the relative temperature of the upper dome when standby time was made into 0 second-300 second. It is a graph which shows the result of having measured the relationship between waiting time and the relative temperature of the upper dome at the time of the 1st-3rd epitaxial growth processing.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of an epitaxial wafer manufacturing apparatus A of the present invention.

As shown in FIG. 1, the epitaxial growth furnace 1 has a chamber 11 for forming an epitaxial layer on a silicon wafer W. The chamber 11 includes an upper dome 12, a lower dome 13, and a dome mount 14 that fixes and supports the upper dome 12 and the lower dome 13. The upper dome 12 and the lower dome 13 are made of a transparent material such as quartz, and are mounted on a susceptor 16 and a susceptor 16 described later by a plurality of halogen lamps 15 arranged above and below the epitaxial growth furnace 1. The silicon wafer W is heated. As shown in a part of FIG. 1, the plurality of halogen lamps 15 are annularly arranged above and below the epitaxial growth furnace 1, and the output of each halogen lamp 15 is controlled by the driving unit 24. The section 24 is controlled by a control signal from the controller 5.

The epitaxial growth furnace 1 further includes a susceptor 16 that partitions the chamber 11 into an upper space 11a and a lower space 11b. The susceptor 16 has a disc shape, is fixed to the outer peripheral portion of the lower surface of the susceptor by a support arm 18 connected to the susceptor rotating shaft 17, and is rotated by rotationally driving the susceptor rotating shaft 17. Further, in the outer peripheral portion of the susceptor 16, a total of three through holes are formed every 120 degrees in the circumferential direction. A lift pin 19 for lifting the silicon wafer W is loosely inserted in each through hole. Lifting of the lifting pins 19 is performed by a lift arm 20. The rotational drive of the susceptor rotary shaft 17 and the vertical drive of the lift arm 20 are performed by a drive unit 21, and the drive unit 21 is controlled by a command signal from the controller 5.

The material of the susceptor 16 is not particularly limited as long as the surface of the susceptor 16 is made of SiC in order to prevent impurities from being mixed in when forming the epitaxial layer. Generally, a carbon substrate having a surface coated with a silicon carbide (SiC) film is often used, but the entire susceptor 16 may be formed of SiC.

A gas supply port 22 and a gas discharge port 23 are arranged to face each other at a height position of the dome mounting body 14 that is substantially equal to the upper surface of the susceptor 16. During the epitaxial growth process, a silicon reaction gas such as trichlorosilane (SiHCl ₃ ) is diluted with a carrier gas such as hydrogen gas (H ₂ gas) into the chamber 11 from the gas supply port 22, and diborane is added as necessary. A mixed gas in which a small amount of a dopant such as (B ₂ H ₆ ) is mixed is supplied in parallel (horizontal direction) to the upper surface of the silicon wafer W. The supplied mixed gas passes through the surface of the silicon wafer W to grow an epitaxial layer, and then is discharged from the chamber 11 through the gas discharge port 23.

On the other hand, during the cleaning process, a cleaning gas such as hydrogen chloride (HCl) gas is supplied according to a predetermined procedure while the silicon wafer W is unloaded from the chamber 11 through a gate valve (not shown) by a wafer transfer mechanism (not shown). The gas is introduced into the chamber 11 through the port 22 and discharged through the gas discharge port 23. As a result, the deposits attached to the susceptor 16 and the like are removed by dry etching. The supply and discharge of the reaction gas and the cleaning gas are performed by the gas supply system 3, and the gas supply system 3 is controlled by the control signal from the controller 5.

An infrared radiation temperature sensor 4 is provided in the central portion above the epitaxial growth furnace 1, and the amount of infrared radiation emitted from the silicon wafer W is optically detected via the upper dome 12, whereby the silicon wafer W Detects the surface temperature without contact. It should be noted that the object radiates infrared rays from its surface, and the temperature of the object surface is determined by the amount of infrared rays, and the infrared rays have a characteristic of carrying energy through space. The infrared radiation temperature sensor 4 optically reads the infrared rays transmitted through this space and measures the temperature without bringing the object into contact with the sensor. The detection signal detected by the infrared radiation temperature sensor 4 is read out to the controller 5, and the controller 5 outputs the output of the halogen lamp 15 from the drive unit 24 according to the surface temperature of the silicon wafer W detected by the controller 5. For example, PID control (Proportional Integral Differential Controller) is performed. That is, during the epitaxial growth process, the drive unit 24 is controlled so that the surface temperature of the silicon wafer W falls within a predetermined temperature range, and the output of each halogen lamp 15 is controlled. For example, when the detected surface temperature of the silicon wafer W is lower than the predetermined temperature range, the output of the halogen lamp 15 is increased, and when it is higher than the predetermined temperature range, the output of the halogen lamp 15 is decreased.

The controller 5 is composed of a computer having a CPU, a ROM, a RAM, and the like, and controls a wafer transfer mechanism and a gate valve (not shown), the gas supply system 3, the driving unit 24 of the halogen lamp 15, and the driving unit 21 of the susceptor 16. Therefore, a processing program (hereinafter also referred to as a process recipe) of an apparatus regarding a process sequence and control parameters (control target values such as temperature, pressure, gas type and gas flow rate, time) for manufacturing an epitaxial wafer, and epitaxial growth. A process program (hereinafter also referred to as a cleaning recipe) regarding a process sequence and control parameters for cleaning the furnace and the exhaust pipe is established, and the process recipe is read during the epitaxial growth process, and the wafer transfer mechanism, the gate valve, the gas supply system are read. 3, the drive unit 24 of the halogen lamp 15 and the drive unit 21 of the susceptor 16 are controlled so that the cleaning recipe is read during the cleaning process, and the wafer transfer mechanism, the gate valve, the gas supply system 3, and the drive unit 24 of the halogen lamp 15 are read. It also controls the drive unit 21 of the susceptor 16.

In the epitaxial wafer manufacturing apparatus A of this embodiment, a so-called multi-depot process is executed. The multi-depot treatment refers to an operation system in which after performing the epitaxial manufacturing treatment a plurality of times in succession, a cleaning treatment for removing deposits accumulated in the chamber 11 is performed once. An example of multi-depot processing is shown in FIG. In the example shown in the figure, after the epitaxial growth treatment of the first time, the second time, and the third time is continuously performed, the cleaning process is performed once, and this is repeated.

A gate valve and a load lock chamber (not shown) are provided on one side surface of the epitaxial growth furnace 1, and the silicon wafer W before the epitaxial growth process is loaded into the chamber 11 from the load lock chamber through the gate valve and after the epitaxial growth process. The silicon wafer W is taken out to the load lock chamber via the gate valve. That is, a gate valve (not shown) is opened, and the silicon epitaxial wafer W after film formation is unloaded from the chamber 11 via the gate valve by a wafer transfer mechanism (not shown). Then, the gate valve is closed and the driving unit 24 is controlled to control the output of the halogen lamp 15 to raise the temperature in the chamber 11 of the epitaxial growth furnace 1 to a predetermined temperature, and the gas supply system 3 is controlled to control the chamber. A cleaning gas such as hydrogen chloride gas or chlorine trifluoride gas is supplied into the chamber 11 for a predetermined time to remove deposits (cleaning process). Next, the halogen lamp 15 is turned off, and the chamber 11 of the epitaxial growth furnace 1 is purged with hydrogen gas and cooled. Here, the temperature rise to the predetermined temperature (cleaning process temperature) is preferably 1130° C. to 1250° C., and the higher the temperature, the shorter the cleaning gas supply time can be. Then, the predetermined time for supplying the cleaning gas is set to such a time as to remove the silicon deposits deposited in the chamber and also remove the silicon deposits attached to the inner wall of the quartz upper dome 12. The cleaning treatment temperature is preferably set higher than the temperature of the epitaxial growth treatment described later. Thereby, the silicon deposit can be cleaned in a short time.

When the cleaning process is completed, a silicon wafer W before film formation is loaded into the chamber 11, and then the driving unit 24 is controlled to control the output of the halogen lamp 15 to control the internal temperature of the chamber 11 between 1000 and 1200°C. The temperature is raised to a predetermined temperature by controlling the gas supply system 3, and the reaction gas such as monosilane gas (SiH ₄ ) or silane chloride gas (SiH ₂ Cl ₂ , SiHCl ₃ ) is supplied into the chamber 11 with hydrogen or an inert gas. The carrier gas is supplied for a predetermined time to form an epitaxial layer on the surface of the silicon wafer W (epitaxial growth process). Next, after turning off the halogen lamp 15 and purging the inside of the chamber 11 with hydrogen gas to cool it, the silicon epitaxial wafer W after the film formation is carried out from the chamber 11, and the silicon wafer W before the next film formation is carried out. Then, the epitaxial growth process is performed in the same manner as the first epitaxial growth process. After repeating the epitaxial growth process three times, the cleaning process described above is performed.

Here, the inventors of the present invention have sought to find that, under the condition that the cleaning treatment temperature is set higher than the epitaxial growth treatment temperature, the film formation is performed depending on the time between the completion of the cleaning treatment and the first epitaxial growth treatment. It was found that the film thickness of the formed silicon epitaxial wafer W varies. FIG. 3 shows that the cleaning process ends when the cleaning process and the epitaxial growth process are performed three times under the same conditions using the same epitaxial wafer manufacturing apparatus A under the condition that the cleaning process temperature is set higher than the epitaxial growth process temperature. The time (hereinafter, also referred to as standby time, which is also the cooling time of the chamber 11) between the first and the first epitaxial growth treatment is 0 seconds, 60 seconds, 120 seconds, 180 seconds, 240 seconds, and It is a graph which shows the result of the confirmation experiment which measured the relative film thickness of the center of the wafer of an epitaxial layer when it was 300 seconds. The epitaxial thickness was 4 μm. According to the result of this confirmation experiment, the increase/decrease rate of the film thickness of the second time and the film thickness of the third time is increased or decreased by 0.2% or less at any level, which is not so different. It was found that the increase/decrease rate of the film thickness of the first time and the film thickness of the second time and thereafter decreased at a value exceeding 0.5%, which is not negligible. The shorter the waiting time, the thicker the first film thickness, and the longer the waiting time, the thinner the first film thickness. Therefore, it can be understood that the increase/decrease rate of the film thickness of the first time and the film thickness of the second time and thereafter is reduced by selecting an appropriate time. The rate of increase/decrease is ((absolute value of ((n+1)th value [μm]-nth value [μm]))/nth value [μm]×100[%] (where n is 1 The value defined above is used.

Since the film thickness of the epitaxial layer during the epitaxial growth process becomes thicker as the surface temperature of the silicon wafer W increases, the controller 5 controls the halogen lamp 15 of the halogen lamp 15 according to the surface temperature of the silicon wafer W detected by the infrared radiation temperature sensor 4. The output is subjected to PID control so that the surface temperature of the silicon wafer W falls within a predetermined temperature range. FIG. 4 is a graph showing the measurement result of the relative temperature of the surface of the silicon wafer W detected by the infrared radiation temperature sensor 4 in the confirmation experiment described above. According to this result, the surface temperature of the silicon wafer W is maintained in the predetermined temperature range from the first time to the third time. Although the surface temperature of the silicon wafer W is maintained within the predetermined temperature range as described above, the difference between the film thickness of the first time and the film thickness of the second time and thereafter becomes large as shown in FIG. There is. The fluctuation of the surface temperature of the silicon wafer W is preferably ±1 degree or less.

By the way, FIG. 5 is a graph showing the result of measuring the fluctuation of the relative output of the halogen lamp 15 in the above-mentioned confirmation experiment. According to this result, the output of the halogen lamp 15 is controlled to be smaller as the standby time is shorter, and the output of the halogen lamp 15 is controlled to be larger as the standby time is longer. This is because the shorter the standby time is, the higher the internal temperature of the epitaxial growth furnace 1 is maintained, so that control is performed so that the output of the halogen lamp 15 becomes smaller. The longer the standby time, the lower the internal temperature of the epitaxial growth furnace 1. It is considered that this is because the control in the direction of increasing the output of the halogen lamp 15 is executed.

However, as shown in FIGS. 4 and 5, although the output of the halogen lamp 15 is PID-controlled so that the surface temperature of the silicon wafer W detected by the infrared radiation temperature sensor 4 falls within a predetermined temperature range. As shown in FIG. 3, the variation in the first film thickness is presumed to be due to some other factor. Therefore, the present inventor paid attention to the temperature of the upper dome 12, and measured the temperature of the upper dome 12 in the above-described confirmation experiment during the epitaxial growth process by using an infrared radiation temperature sensor capable of measuring a quartz surface (not shown). did. The result is shown in FIG. FIG. 6 shows the relative positions of the upper dome 12 when the standby time was set to 0 seconds, 60 seconds, 120 seconds, 180 seconds, 240 seconds, and 300 seconds under the condition that the cleaning processing temperature was set higher than that of the epitaxial growth processing. It is a graph which shows the result of the confirmation experiment which measured temperature. According to this result, the temperature of the upper dome 12 is higher as the waiting time is shorter, and the temperature of the upper dome 12 is lower as the waiting time is longer. That is, when the results of FIG. 6 and the results of FIG. 3 are combined, the higher the temperature of the upper dome 12, the thicker the first film thickness, and the lower the temperature of the upper dome 12, the thinner the first film thickness. , The relationship between temperature and film thickness is matched. Therefore, it is presumed that if the temperature of the upper dome 12 is controlled, it is possible to suppress the first variation in the film thickness shown in FIG. The infrared radiation temperature sensor capable of measuring the quartz surface has a measurement wavelength different from that of the infrared radiation temperature sensor 4. Specifically, the detection range of the infrared radiation temperature sensor 4 is 0.9 to 0.97 μm, and 4.8 to 5.2 μm is used.

FIG. 7 shows the waiting time and the first to the third time when the cleaning process and the epitaxial growth process were performed three times under the same conditions using the same epitaxial wafer manufacturing apparatus A as that used in the confirmation experiment. It is a graph which shows the result of having measured the relation with the relative temperature of the upper dome 12 at the time of the epitaxial growth process of one time. According to this result, the temperature of the upper dome 12 fluctuates only in the first epitaxial growth process, and the temperature of the upper dome 12 in the second and third epitaxial growth processes is almost constant. Is becoming Therefore, it is presumed that if the temperature of the upper dome 12 during the first epitaxial growth process, that is, the waiting time after the cleaning process is controlled, it is possible to suppress the variation in the first film thickness shown in FIG. To be done. Further, the waiting time is set so that the temperature of the upper dome 12 is ±10 degrees or less, preferably ±5 degrees or less in all epitaxial growth processes by using an infrared radiation temperature sensor capable of measuring the quartz surface. be able to.

The variation in the film thickness after the first epitaxial growth treatment due to the temperature of the upper dome 12 is presumed to be due to the following reasons. That is, when the standby time is short, the temperature of the upper dome 12 is high although the output of the halogen lamp 15 is suppressed by the PID control, and the radiant heat from the upper dome 12 causes the actual surface temperature of the silicon wafer W to increase. It is presumed that the temperature is higher than the temperature detected by the infrared radiation temperature sensor 4. Therefore, the actual film thickness becomes thicker than the target film thickness. On the other hand, when the standby time is long, the temperature of the upper dome 12 is sufficiently low and the influence of the radiant heat from the upper dome 12 is extremely small. Therefore, the actual surface temperature of the silicon wafer W has a smaller deviation from the surface temperature of the silicon wafer W detected by the infrared radiation temperature sensor 4, and becomes a surface temperature according to the output of the halogen lamp 15 that is PID-controlled. Therefore, it is estimated that the target film thickness will be obtained.

According to the above confirmation experiment, in the epitaxial wafer manufacturing apparatus A of the present embodiment, the standby time is set to the unique value of the epitaxial wafer manufacturing apparatus A without preparing a plurality of process recipes for the epitaxial growth process. It is possible to reduce the variation between the film thickness after the first epitaxial growth process shown in 3 and the film thickness after the second epitaxial growth process. Since the standby time is expected to vary depending on the individual difference of the epitaxial wafer manufacturing apparatus A and the conditions of the process recipe, the first time when a plurality of standby times are set for each epitaxial wafer manufacturing apparatus A and each process recipe Data of the film thickness of the epitaxial layer during the epitaxial growth process and the film thickness during the second and subsequent epitaxial growth processes is acquired by experiment or computer simulation, and the increase/decrease rate of these film thicknesses falls within a predetermined allowable range. The range of the waiting time of is acquired in advance. Then, during the actual production, using the range of the waiting time thus acquired, if the time after the cleaning process is finished is within the range of the waiting time, the next wafer is permitted to be input and the cleaning process is finished. If the time after that is not within the range of the waiting time, the controller 5 controls so as to prohibit the input of the next wafer. In addition, the upper dome temperature can be acquired in the same manner and the range of the waiting time when the upper dome temperature falls within a predetermined allowable range can be acquired. The output of the halogen lamp 15 can be further stabilized by stabilizing the temperature in the equipment state, especially in the quartz upper dome. The permission and prohibition of the next wafer loading can be performed by controlling the wafer transfer mechanism (not shown) by the controller 5. The predetermined range of the rate of increase/decrease is preferably ±0.5% or less, and more preferably ±0.2% or less. Here, when displayed with ±, it indicates the direction of increase and decrease.

As described above, the film thickness during the first epitaxial growth process and the film thickness during the second and subsequent epitaxial growth processes in the multi-deposition process have a strong correlation with the temperature of the upper dome 12, and therefore, as shown in FIG. The temperature of the upper dome 12 with respect to the standby time was measured, and the variation rate between the temperature of the upper dome 12 during the first epitaxial growth treatment and the temperature of the upper dome 12 during the second and subsequent epitaxial growth treatments was within a predetermined range. The range of the waiting time to enter may be obtained in advance. Instead of this, the film thickness during the first epitaxial growth process and the film thickness during the second and subsequent epitaxial growth processes in the multi-deposition process also have a strong correlation with the output of the halogen lamp 15. Therefore, as shown in FIG. In addition, the output of the halogen lamp 15 for a plurality of standby times is measured, and the fluctuation rate between the output of the halogen lamp 15 during the first epitaxial growth process and the output of the halogen lamp 15 during the second and subsequent epitaxial growth processes is predetermined. The range of the waiting time that falls within the range may be obtained in advance.

Table 1 shows the results of the fluctuation rate of the output of the halogen lamp 15 shown in FIG. 5 and the increase/decrease rate of the epitaxial film shown in FIG. It should be noted that the fluctuation rate of the output of the halogen lamp 15 is (output of the halogen lamp 15 during the second and subsequent epitaxial growth processes-output of the halogen lamp 15 during the first epitaxial growth process)/(during the first epitaxial growth process) Output of the halogen lamp 15). The rate of increase/decrease in the film thickness of the epitaxial layer is shown in Table 1 based on the above definition, based on the above-mentioned definition.

In the results of the epitaxial wafer manufacturing apparatus A shown in FIG. 5, the fluctuation rate when the standby time is 0 second is 1.64%, the fluctuation rate when 60 seconds is 1.25%, and the fluctuation time is 120 seconds. The rate is 0.50%, the variation rate at 180 seconds is 0.25%, the variation rate at 240 seconds is -0.49%, and the variation rate at 300 seconds is -0.98%. On the other hand, the rate of increase and decrease in film thickness between the first and second times shown in FIG. 3 is 0.55% when the standby time is 0 seconds, and the increase or decrease in film thickness when the standby time is 60 seconds. The rate is 0.42%, the film thickness change rate at 120 seconds is 0.18%, the film thickness change rate at 180 seconds is 0.03%, and the film thickness change rate at 240 seconds is 0.13%. %, the rate of change in film thickness at 300 seconds is 0.16%. By setting the allowable range of the increase/decrease rate of the thickness of the epitaxial layer to 0.20% or less, the variation of the film thickness is suppressed when the variation rate of the output of the halogen lamp 15 is in the range of ±0.98%.

A... Epitaxial wafer manufacturing apparatus 1... Epitaxial growth furnace 11... Chamber 12... Upper dome 13... Lower dome 14... Dome mount 15... Halogen lamp 16... Susceptor 16a... Outer peripheral portion 17... Susceptor rotating shaft 18... Support arm 19... Lifting pin 20... Lift arm 21... Drive unit 22... Gas supply port 23... Gas discharge port 24... Drive unit 3... Gas supply system 4... Infrared radiation temperature sensor 5... Controller W... Silicon wafer

Claims (5)

Put one wafer at a time in the chamber of the epitaxial growth furnace,
While measuring the temperature of the surface of the wafer by the non-contact temperature sensor, controlling the output of the heater to heat the inside of the chamber so that the detected temperature is within a predetermined temperature range,
A method of manufacturing an epitaxial wafer in which an epitaxial layer is vapor-grown on a surface of the wafer while supplying a reaction gas into the chamber,
In a method for manufacturing an epitaxial wafer, after performing a plurality of epitaxial growth treatments successively, a cleaning treatment for removing deposits accumulated in the chamber is performed once,
The waiting time from the end of the cleaning process to the loading of the first wafer into the chamber is such that the fluctuation rate of the output of the heater during the plurality of epitaxial growth processes falls within a predetermined range. A method for manufacturing an epitaxial wafer in which an epitaxial growth process is performed by setting the time. The standby time is the output of the heater when performing the first epitaxial growth treatment after the cleaning treatment is finished and the output of the heater when performing the second and subsequent epitaxial growth treatments. The method for producing an epitaxial wafer according to claim 1, wherein the fluctuation rate is a time within a range of ±0.5%. A quartz upper dome is provided on the upper portion of the epitaxial growth furnace,
The method for manufacturing an epitaxial wafer according to claim 1, wherein the non-contact temperature sensor detects the temperature of the surface of the wafer from outside the epitaxial growth furnace through the quartz dome. The method for manufacturing an epitaxial wafer according to claim 1, wherein the non-contact temperature sensor is an infrared radiation temperature sensor. A single-wafer epitaxial growth furnace having at least a quartz upper dome;
A susceptor for mounting a wafer,
A gas supply system for supplying a reaction gas or a cleaning gas into the chamber of the epitaxial growth furnace;
A heater for heating the inside of the chamber,
An infrared radiation temperature sensor for detecting the temperature of the surface of the wafer from outside the chamber through the quartz upper dome;
While controlling the output of the heater so that the temperature detected by the infrared radiation temperature sensor falls within a predetermined temperature range, and a controller that controls the gas supply system, in an epitaxial wafer manufacturing apparatus,
The controller is
The gas supply system is controlled so that the cleaning process for removing the deposit accumulated in the chamber is performed once after the epitaxial growth process is continuously performed a plurality of times,
The waiting time from the end of the cleaning process to the loading of the first wafer into the chamber is such that the fluctuation rate of the output of the heater during the multiple epitaxial growth processes falls within a predetermined range. Set in time,
Until the time from the end of the cleaning process reaches the waiting time, the first wafer loading is prohibited, and if the time from the end of the cleaning process exceeds the waiting time, An epitaxial wafer manufacturing apparatus that permits the first wafer loading.

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