JP5710382B2 - Manufacturing method of semiconductor device - Google Patents

Description

  The technology disclosed in this specification relates to a method for manufacturing a semiconductor device.

  When manufacturing a power semiconductor device that handles a large current, a thick film may be grown on the surface of a semiconductor wafer. However, if the semiconductor wafer becomes excessively thicker than a general thickness by growing a thick film, it becomes difficult to process the semiconductor wafer with a general processing facility. In order to solve this problem, a semiconductor wafer having a thin original thickness is used so that the thickness of the semiconductor wafer after growing the film becomes a predetermined thickness, and a thick film is formed on the surface of the semiconductor wafer. Methods for growing are known. As another method, a method is known in which after a film is grown, the back surface of the semiconductor wafer (the surface opposite to the grown film) is polished or etched to thin the semiconductor wafer.

JP-A-9-52796

  In the method of growing a film on the surface of an original thin semiconductor wafer, the following problems occur. That is, since it is difficult to handle a thin semiconductor wafer, chipping may occur in the semiconductor wafer during the handling, or slip defects may occur in the semiconductor wafer due to temperature changes.

  In addition, in the method of thinning the semiconductor wafer by polishing or etching the back surface of the semiconductor wafer after the film is grown, there is a possibility that the quality of the film is deteriorated because such processing is performed after the film is grown. .

  In any of the above-described methods, when a film is grown, the film also grows on the surface of an apparatus in the chamber of the film forming apparatus (for example, the surface of a susceptor on which a semiconductor wafer is placed). For this reason, after performing the film forming process, it is necessary to perform a cleaning process in which an etching gas is introduced into the empty chamber to remove the film grown on the surface of the equipment inside the chamber. This cleaning process becomes a factor of lowering the manufacturing efficiency of the semiconductor device.

  Therefore, the present specification is a technique for growing a film on the surface of a semiconductor wafer, can suppress an increase in the thickness of the semiconductor wafer, can improve the quality of the semiconductor wafer, and A technology capable of efficiently manufacturing a device is provided.

  Patent Document 1 discloses a technique for growing a film on the surface of a semiconductor wafer after etching the semiconductor wafer.

  In order to solve the problems of the conventional methods described above, the present inventors use a semiconductor manufacturing apparatus capable of performing an operation of growing a film on the surface of a semiconductor wafer and an operation of etching the semiconductor wafer as follows. I devised a technique for growing films. In this technique, a semiconductor wafer is placed in a chamber of a semiconductor manufacturing apparatus, and the semiconductor wafer is first etched. This thins the semiconductor wafer. Next, a film is grown on the surface of the semiconductor wafer. According to this method, even if a semiconductor wafer having a thick original thickness is used, a film is grown on the surface of the semiconductor wafer after the semiconductor wafer is thinned by etching. Don't get too thick. In addition, since the film can be grown on the surface of the semiconductor wafer without moving it after etching, it is possible to suppress chipping in the semiconductor wafer or defects in the semiconductor wafer. Further, since the processing for thinning the semiconductor wafer after the film formation is unnecessary, the quality of the film can be maintained. However, even with this technique, since it is necessary to carry out a cleaning process, the manufacturing efficiency of the semiconductor device cannot be improved so much.

Therefore, the present inventors have created the following manufacturing method by further improving the above manufacturing method. In this manufacturing method, a susceptor disposed in a chamber is provided, an operation of growing a film on the surface of a semiconductor wafer disposed on the susceptor , and etching of the semiconductor wafer disposed on the susceptor and the film are etched. A semiconductor manufacturing apparatus capable of performing an operation of introducing a possible etching gas into the chamber is used. The manufacturing method includes a carry-in process, a first etching process, a first film forming process, a replacement process, a second etching process, and a second film forming process. In the carry-in process, the semiconductor wafer is carried onto the susceptor in the chamber of the semiconductor manufacturing apparatus. In the first etching process , the semiconductor wafer is etched by introducing the etching gas into the chamber after the carrying-in process. In the first film formation step, a film is grown on the surface of the semiconductor wafer in the chamber after the first etching step. In the replacement step, after the first film formation step, the semiconductor wafer is unloaded from the chamber and another semiconductor wafer is placed on the susceptor in the chamber. In the second etching process, the film on the surface of the semiconductor wafer and the susceptor is etched by introducing the etching gas into the chamber after the replacement process. In the second film formation step, a film is grown on the surface of the semiconductor wafer in the chamber after the second etching step. In the replacement process, the cleaning process for removing the film formed on the surface of the susceptor is not performed between the time when the semiconductor wafer is unloaded from the chamber and the time when another semiconductor wafer is placed on the susceptor in the chamber.

  In this manufacturing method, a semiconductor wafer (hereinafter referred to as a first semiconductor wafer) is carried into the chamber in the carry-in process, the first semiconductor wafer is thinned in the first etching process, and then the first film-forming process. A film is grown on the surface of one semiconductor wafer. In the first film formation step, a film also grows on the surface of equipment in the chamber of the semiconductor manufacturing apparatus. When the first film formation step is completed, the semiconductor wafer is replaced in the replacement step. Then, a second etching process is performed on a semiconductor wafer newly loaded into the chamber (hereinafter referred to as a second semiconductor wafer). In the second etching step, the second semiconductor wafer is etched and the film formed on the surface of the device in the chamber is also etched. That is, in the second etching step, the chamber is cleaned at the same time as the second semiconductor wafer is thinned. When the second etching process is completed, a film is grown on the surface of the second semiconductor wafer in the second film forming process. As described above, in this manufacturing method, film formation is performed after etching each semiconductor wafer. Therefore, in this manufacturing method, it is possible to grow a film on the surface of the semiconductor wafer while suppressing an increase in the thickness of the semiconductor wafer and maintaining the quality of the semiconductor wafer. In the second etching step, the chamber can be cleaned simultaneously with the etching of the second semiconductor wafer. That is, the etching process and the cleaning process, which are conventionally performed separately, can be performed simultaneously. Therefore, according to this manufacturing method, a semiconductor device can be manufactured with high manufacturing efficiency.

  In the manufacturing method described above, it is preferable that the etching thickness of the semiconductor wafer in the second etching step is larger than the thickness of the film grown in the first film forming step. Note that the etching thickness of the semiconductor wafer means a difference between the thickness of the semiconductor wafer before the second etching process and the thickness of the semiconductor wafer after the second etching process.

  According to such a configuration, almost all of the film grown on the surface of the device in the chamber in the first film forming process can be removed in the second etching process. Therefore, even if this manufacturing method is repeatedly performed, it is possible to prevent the film from growing on the surface of the equipment in the chamber.

  In the manufacturing method described above, it is preferable to grow a film having a thickness of 100 μm or more in the first film formation step and the second film formation step.

In the manufacturing method described above, it is preferable that the susceptor includes a mounting surface on which the semiconductor wafer is mounted. In the second etching step, it is preferable to perform etching until all the films grown on the mounting surface in at least the first film forming step are removed. More preferably, in the second etching step, it is preferable to perform etching until all the films grown on the surface of the susceptor in the first film forming step are removed. Thus, by removing unnecessary films existing in the vicinity of the semiconductor wafer, it is possible to manufacture a higher quality semiconductor device.

1 is a schematic sectional view of a semiconductor manufacturing apparatus. 5 is a flowchart showing a film forming process. The figure which shows the temperature profile of the susceptor in the film-forming process, and the gas supplied in a chamber. FIG. 4 is a longitudinal sectional view of the susceptor 16 in a replacement process after a deposited semiconductor wafer is unloaded and before a new semiconductor wafer is loaded. The longitudinal section of susceptor 16 in the state after carrying in new semiconductor wafer 50 in the exchange process. The longitudinal cross-sectional view of the susceptor 16 after an etching process. The longitudinal cross-sectional view of the susceptor 16 after the film-forming process.

  In the manufacturing method of this embodiment, the semiconductor wafer 50 is processed using the semiconductor manufacturing apparatus 10 shown in FIG. The semiconductor wafer 50 is a semiconductor wafer made of p-type silicon. First, the semiconductor manufacturing apparatus 10 will be described. The semiconductor manufacturing apparatus 10 includes a first housing 12 and a second housing 14 installed in the first housing 12. A chamber 15 is formed by the internal space of the second housing 14. A susceptor 16 is installed in the chamber 15.

  The susceptor 16 is a cylindrical member, and includes a holder portion 17 having a large diameter and a shaft portion 18 having a small diameter. A bearing portion 20 is formed at the bottom of the housing 12. The shaft portion 18 of the susceptor 16 is inserted into the bearing portion 20. As a result, the susceptor 16 can be rotated as indicated by an arrow 60 in FIG. The susceptor 16 can be rotated by a driving device (not shown). The holder part 17 is located in the chamber 15. A recess is formed in the center of the upper surface of the holder portion 17. The bottom surface 17a of the recess is a mounting surface on which the semiconductor wafer 50, on which the epitaxial layer is grown, is mounted. As shown in FIG. 5, the mounting surface 17 a has a region 17 c that is covered with the semiconductor wafer 50 when the semiconductor wafer 50 is mounted, and a region 17 d that is not covered with the semiconductor wafer 50 at that time. . As shown in FIG. 1, a convex portion 17e protruding upward from the placement surface 17a is formed around the placement surface 17a. An opening 17b is formed in the center of the mounting surface 17a. The semiconductor wafer 50 is mounted on the mounting surface 17a so as to close the opening 17b. Inside the holder part 17, a resistance heating type heater 22 is installed. The heater 22 is installed immediately below the opening 17b. Therefore, the semiconductor wafer 50 placed on the placement surface 17a can be heated by the heater 22.

Gas supply paths 24 a and 24 b are connected to the upper portion of the chamber 15. The gas supply paths 24 a and 24 b are drawn out of the housing 12. The upstream ends of the gas supply paths 24 a and 24 b are connected to the gas supply device 25. The gas supply device 25 can supply various gases into the gas supply paths 24a and 24b. Specifically, the gas supply device 25 can supply H ₂ gas (hydrogen gas) into the gas supply paths 24a and 24b. In addition, the gas supply device 25 includes a mixed gas (hereinafter, this mixed gas) of H ₂ gas, SiHCl ₃ gas (trichlorosilane gas), and PH ₃ gas (hydrogen phosphide gas) in the gas supply paths 24a and 24b. , Referred to as a raw material mixed gas). H ₂ gas and SiHCl ₃ gas are gases that cause a silicon film to grow epitaxially on the surface of the semiconductor wafer 50 by reacting with each other. The PH ₃ gas is a dopant gas for doping phosphorus into the epitaxially grown silicon film to make the silicon film N-type. The gas supply device 25 can supply a mixed gas of H ₂ gas and HCl gas (hydrochloric acid gas) into the gas supply paths 24a and 24b. HCl gas is an etching gas for etching silicon. A shower plate 26 is installed in the upper part of the chamber 15 so as to separate the gas supply paths 24 a and 24 b from the chamber 15. The shower plate 26 includes a large number of communication holes that communicate with the front and back surfaces thereof. Therefore, the gas supplied from the gas supply device 25 is supplied into the chamber 15 through the gas supply paths 24 a and 24 b and the shower plate 26.

  Exhaust passages 28 a and 28 b are connected to the bottom surface of the chamber 15. The downstream ends of the exhaust passages 28 a and 28 b are connected to the exhaust pump 29. The exhaust pump 29 discharges the gas in the exhaust passages 28a and 28b to the outside. By operating the exhaust pump 29, the inside of the chamber 15 can be depressurized.

  A water-cooled tube 32 is disposed between the outer peripheral wall of the casing 14 and the outer peripheral wall of the casing 12. Cold water can be circulated in the water cooling pipe 32. The water cooling pipe 32 can cool the outer peripheral wall of the casing 14 (that is, the outer peripheral wall of the chamber 15). Thereby, it is suppressed that the gas in the chamber 15 reacts on the surface of the outer peripheral wall.

  Next, the manufacturing method of an Example is demonstrated. First, the outline of the manufacturing method of the embodiment will be described with reference to FIG. As shown in FIG. 2, in the manufacturing method of the embodiment, after the carry-in process S2, the etching process S4, the film forming process S6, and the replacement process S8 are repeatedly performed. In the loading step S <b> 2, the semiconductor wafer 50 is loaded into the chamber 15. In the etching step S4, an etching gas is introduced into the chamber 15 to etch the semiconductor wafer 50. Thereby, the semiconductor wafer 50 is thinned to a predetermined thickness. In the film forming step S <b> 6, a raw material mixed gas is introduced into the chamber, and a silicon film is epitaxially grown on the surface of the semiconductor wafer 50. When the silicon film is grown, the silicon film also grows on the surface of the device in the chamber 15. When the film forming step S6 is completed, the semiconductor wafer on which the silicon film is formed is completed. In the replacement step S8, the semiconductor wafer 50 in the chamber 15 is replaced. That is, the semiconductor wafer 50 on which film formation has been completed is unloaded from the chamber 15, and a new semiconductor wafer 50 before film formation is loaded into the chamber 15. Thereafter, steps S4 to S8 are repeated. At the start of the second and subsequent etching steps S4, the silicon film formed in the film forming step S6 performed in advance is present on the surface of the device in the chamber 15. Accordingly, in the second and subsequent etching steps S4, the semiconductor wafer 50 is etched and the silicon film formed on the surface of the device in the chamber 15 is also etched. Thereby, cleaning of the chamber 15 is performed simultaneously with the etching of the semiconductor wafer 50. Thus, the silicon film grown on the surface of the device in the chamber 15 in the film forming step S6 for the previous semiconductor wafer 50 is removed in the etching step S4 for the next semiconductor wafer 50. By repeatedly performing each step of FIG. 2, the semiconductor wafer 50 on which the silicon film is formed can be mass-produced.

  Next, the manufacturing method of an Example is demonstrated in detail. The semiconductor wafer 50 (semiconductor wafer 50 before film formation) used in the manufacturing method of the embodiment is a silicon wafer having a thickness of about 725 μm. In order to suppress the occurrence of crystal defects in the semiconductor wafer during etching, it is preferable to use a silicon wafer having as low an oxygen concentration and defect density as possible for the semiconductor wafer 50. In order to ensure mechanical strength, it is preferable to use a silicon wafer containing a high concentration of p-type impurities (for example, boron) as the semiconductor wafer 50.

  FIG. 3 shows the temperature profile of the susceptor 16 and the gas introduced into the chamber 15 when the steps S4 to S8 of FIG. Note that the temperature control shown in FIG. 3 is performed by the heater 22. Further, the supply and stop of the gas shown in FIG. Each of the cycles C <b> 1 to C <b> 3 is a cycle of processing performed on one semiconductor wafer 50. Since the processing performed in each cycle is the same, the cycle C2 will be mainly described below.

As shown in FIG. 3, H ₂ gas is always supplied into the chamber 15 by the gas supply device 25 during the process of repeating steps S4 to S8. Further, the exhaust pump 29 is operating during this process. The pressure in the chamber 15 is appropriately controlled by the gas supply device 25 and the exhaust pump 29.

  When the processing for the semiconductor wafer 50 is completed in the cycle C1, the semiconductor wafer 50 after film formation is unloaded from the chamber 15 in the last replacement step S8 of the cycle C1, and a new semiconductor wafer 50 before film formation is placed in the chamber 15. It is brought in. That is, as shown in FIG. 1, a new semiconductor wafer 50 is placed on the placement surface 17 a of the susceptor 16. When a new semiconductor wafer 50 is carried into the chamber 15, a processing cycle C <b> 2 for the new semiconductor wafer 50 starts. When a new semiconductor wafer 50 is loaded, the chamber 15 is closed. Since the replacement step S8 includes a step of loading a new semiconductor wafer 50 into the chamber 15, it can also be regarded as a loading step.

  FIG. 4 shows a cross-sectional view of the susceptor 16 (that is, the susceptor 16 in which the semiconductor wafer 50 is not placed) immediately after the semiconductor wafer 50 processed in the cycle C1 is unloaded from the chamber 15. As shown in the drawing, a silicon film 80 is formed on the surface of the region 17d (the region of the mounting surface 17a that is not covered with the semiconductor wafer 50) and the convex portion 17e. As will be described in detail later, the thickness of the silicon film 80 is 145 μm or less. The silicon film 80 is grown in the film forming step S6 of the cycle C1. Although not shown, the silicon film 80 is also formed on the side surface of the susceptor 16 and the wall surface of the chamber 15. However, the thickness of the silicon film 80 on the side surface of the susceptor 16 and the wall surface of the chamber 15 is not as thick as described above. Since the silicon film 80 is already formed on the surface of the susceptor 16 as shown in FIG. 4, when a new semiconductor wafer 50 is placed on the susceptor 16, the state shown in FIG. 5 is obtained.

Next, preparatory process S3 is implemented. As shown in FIG. 3, in the replacement step S8, the susceptor 16 is maintained at a low temperature of about 800.degree. In the preparation step S3, the temperature of the susceptor 16 is increased from about 800 ° C. to about 1200 ° C. When the temperature of the susceptor 16 is increased, the temperature of the semiconductor wafer 50 placed on the susceptor 16 is also increased to substantially the same temperature as the susceptor 16 (that is, approximately 1200 ° C.). Thereafter, the temperature of the susceptor 16 is maintained at a substantially constant temperature until the film forming step S6 is completed. In the preparation step S3, the pressure in the chamber 15 is controlled to a predetermined value. Thereafter, the pressure in the chamber 15 is maintained substantially constant until the film forming step S6 is completed. In the preparation step S3, the susceptor 16 is rotated at a high speed around its central axis. The rotation of the susceptor 16 is maintained until the film forming step S6 is completed. In preparation step S 3, H ₂ gas is supplied into the chamber 15. The H ₂ gas that has flowed into the chamber 15 from the shower plate 26 flows toward the semiconductor wafer 50 as indicated by an arrow 70 in FIG. Under the influence of the high-speed rotation of the susceptor 16, the H ₂ gas flows at a high speed along the surface of the semiconductor wafer 50 toward the outer periphery of the semiconductor wafer 50 as indicated by an arrow 72. Most of the gas that has flowed to the outer peripheral edge of the semiconductor wafer 50 flows as indicated by an arrow 74 and is discharged to the outside through the exhaust passages 28a and 28b. Although not shown, a part of the gas that has flowed to the outer peripheral edge of the semiconductor wafer 50 convects in the chamber 15. Such a gas flow is common in all steps S4 to S7 described later. When the temperature of the susceptor 16 rises to about 1200 ° C., the state is maintained for a certain time. Then, the high-temperature semiconductor wafer 50 is exposed to H ₂ gas flowing along the surface of the semiconductor wafer 50 as indicated by an arrow 72. As a result, the natural oxide film formed on the surface of the semiconductor wafer 50 is removed.

When the preparation step S3 is completed, the etching step S4 is performed. Also in the etching step S4, the temperature of the susceptor 16 is maintained at about 1200 ° C., and the susceptor 16 is maintained in a rotating state. In the etching step S < _b > 4, HCl gas is supplied into the chamber 15 in addition to the H ₂ gas already supplied into the chamber 15. HCl gas flows as indicated by arrows 70-74. The HCl gas flowing along the surface of the semiconductor wafer 50 as shown by the arrow 72 reacts with the semiconductor wafer 50 (ie, silicon) heated to a high temperature, as shown in the following reaction formula.
Si + 3HCl → SiHCl ₃ + H ₂
By this reaction, the surface of the semiconductor wafer 50 is etched. As a result, the semiconductor wafer 50 becomes thinner as shown in FIG. In FIG. 6, a dotted line 52 indicates the shape of the semiconductor wafer 50 before etching. In this embodiment, the semiconductor wafer 50 having a thickness of about 725 μm is etched before the etching step until the thickness becomes 575 μm. That is, the etching thickness (symbol ΔT1 in FIG. 6) in the etching step S4 is about 150 μm. As shown in FIG. 5, a silicon film 80 is formed on the surface of the susceptor 16 before the etching step S4. In the etching step S4, the silicon film 80 is also etched by HCl gas. The silicon film 80 around the semiconductor wafer 50 is etched at substantially the same speed as the semiconductor wafer 50. Further, as described above, the thickness of the silicon film 80 is 145 μm or less, which is smaller than the etching thickness of 150 μm. Therefore, the silicon film 80 on the surface of the region 17d and the convex portion 17e is completely removed by etching. The thin silicon film formed on the side surface of the susceptor 16 and the inner surface of the chamber 15 is also removed almost completely in the etching step S4. As described above, in the etching step S4, simultaneously with the etching of the semiconductor wafer 50, the silicon film formed on the surface of the device in the chamber 15 is removed (ie, cleaned). In this embodiment, by appropriately setting the gas supply amount to the chamber 15, the gas discharge amount from the chamber 15, and the rotation speed of the susceptor 16, the vicinity of the semiconductor wafer 50 indicated by the arrow 72 is set. High-speed gas flow is created stably. By stably creating the flow indicated by the arrow 72, the concentration of HCl gas in the vicinity of the surface of the semiconductor wafer 50 becomes uniform, so that the semiconductor wafer 50 can be etched uniformly.

When the etching step S4 is completed, a gas replacement step S5 is performed. In the gas replacement step S < _b > 5, supply of HCl gas to the chamber 15 is stopped and only H ₂ gas is continuously supplied to the chamber 15. As a result, HCl gas is discharged from the chamber 15.

When the gas replacement step S5 is performed for a predetermined time, the film forming step S6 is performed. Also in the film forming step S6, the temperature of the susceptor 16 is maintained at about 1200 ° C., and the susceptor 16 is maintained in a rotating state. In the film forming step S < _b > ₆ , SiHCl ₃ gas and PH ₃ gas are supplied into the chamber 15 in addition to the H ₂ gas already supplied into the chamber 15. That is, the raw material mixed gas is supplied into the chamber 15. The raw material mixed gas flows as indicated by arrows 70 to 74. As shown by an arrow 72, the raw material mixed gas flowing along the surface of the semiconductor wafer 50 reacts as shown in the following reaction formula by the heat of the semiconductor wafer 50 heated to a high temperature.
SiHCl ₃ + H ₂ → Si + 3HCl
Si on the right side of this reaction formula becomes silicon that adheres to the surface of the semiconductor wafer 50. That is, by this reaction, as shown in FIG. 7, the silicon film 82 is epitaxially grown on the surface of the semiconductor wafer 50. Hereinafter, in the semiconductor wafer 50 after the silicon film 82 shown in FIG. 7 is formed, a portion other than the silicon film 82 (a portion constituted by the semiconductor wafer 50 before the silicon film 82 is formed) is referred to as a substrate region. 84. When the silicon film 82 is grown, P in the PH ₃ gas is taken into the silicon film 82. Therefore, the silicon film 82 is N-type silicon. Further, as described above, the temperature of the susceptor 16 is substantially equal to the temperature of the semiconductor wafer 50. Therefore, the above reaction also occurs on the surface of the susceptor 16, and the silicon film 80 grows on the surface of the susceptor 16. Therefore, as shown in FIG. 7, the silicon film 80 grows thick also on the surface of the region 17d and the protrusion 17e around the semiconductor wafer 50. Although not shown, a thin silicon film also grows on the side surface of the susceptor 16 and the inner surface of the chamber 15. Note that the thickness of the silicon film grown on the surface of the semiconductor wafer 50 in the film forming step S6 (thickness ΔT2 in FIG. 7) is about 145 μm. Therefore, the thickness of the silicon film 82 grown on the surface of the susceptor 16 is 145 μm or less even at the thickest portion. Even in the film forming step S6, a high-speed gas flow in the vicinity of the semiconductor wafer 50 indicated by the arrow 72 is stably generated. Accordingly, the silicon film 82 can be grown on the surface of the semiconductor wafer 50 with a uniform thickness.

When the film forming step S6 is completed, a cooling step S7 is performed. In the cooling step S < _b > 7, the supply of SiHCl ₃ gas and PH ₃ gas to the chamber 15 is stopped and only H ₂ gas is continuously supplied to the chamber 15. As a result, SiHCl ₃ gas and PH ₃ gas are discharged from the chamber 15. In the cooling step S7, the temperature of the susceptor 16 is lowered from about 1200 ° C. to about 800 ° C.

  When the temperature of the susceptor 16 is lowered to about 800 ° C., the semiconductor wafer 50 that has been formed is unloaded from the chamber 15 in a replacement step S8, and a new semiconductor wafer 50 that has not been formed is loaded into the chamber 15. At the stage where a new semiconductor wafer 50 is carried into the chamber 15, the next cycle C3 is started. Also in the etching step S4 of cycle C3, the semiconductor wafer 50 is thinly processed by etching, and the silicon film on the surface of the device in the chamber 15 is removed by etching. Then, a silicon film 82 is formed on the surface of the semiconductor wafer 50 in the film forming step S6. As described above, by repeating steps S4 to S8, the semiconductor wafer 50 on which the silicon film 82 is formed can be mass-produced. Various semiconductor devices such as a power semiconductor device can be manufactured using the obtained semiconductor wafer 50.

  As described above, in the manufacturing method of the embodiment, after the semiconductor wafer 50 is thinned by etching, the thick silicon film 82 is epitaxially grown on the surface of the semiconductor wafer 50. Therefore, the semiconductor wafer 50 having the thick silicon film 82 can be obtained without greatly changing the thickness from the original semiconductor wafer 50. Since the thickness of the semiconductor wafer 50 after film formation is substantially the same as that of the semiconductor wafer 50 before film formation, it can be handled using a general processing apparatus. In this manufacturing method, the semiconductor wafer 50 is not transported from the start of the etching process to the end of the film formation process, the pressure in the chamber 15 is maintained substantially constant, and the semiconductor wafer 50 The temperature is maintained approximately constant. That is, almost no stress is applied to the thin semiconductor wafer 50. Therefore, it is possible to suppress chipping in the thin semiconductor wafer 50 and to form defects in the thin semiconductor wafer 50. This reduces defects in the substrate region 84 in the semiconductor wafer 50 after film formation. Further, in this manufacturing method, after the silicon film 82 is formed, processing for thinning the semiconductor wafer 50 is not performed. Therefore, stress is suppressed from being applied to the silicon film 82. As a result, the occurrence of defects or the like in the silicon film 82 is suppressed. Thus, according to this manufacturing method, it is possible to obtain a semiconductor wafer 50 having both the substrate region 84 and the silicon film 82 with high quality.

  Further, in this manufacturing method, simultaneously with the etching of the semiconductor wafer 50, the cleaning in the chamber 15 (that is, the etching of the silicon film 80 formed on the surface of the equipment in the chamber 15) is performed. Therefore, it is not necessary to perform a cleaning process only for cleaning the inside of the chamber 15. For this reason, a semiconductor device can be manufactured efficiently. In particular, when a thick silicon film having a thickness of 100 μm or more is grown on the surface of the semiconductor wafer, the silicon film grown on the surface of the device in the chamber is also thickened. For this reason, in the conventional method, when a silicon film having a thickness of 100 μm or more is grown, it is necessary to perform a cleaning process after each film forming process. For this reason, the time for which the semiconductor manufacturing apparatus is occupied by the cleaning process becomes extremely long. In the manufacturing method of the present embodiment, there is no time for the semiconductor manufacturing apparatus to be occupied by the cleaning process, so that the manufacturing efficiency of the semiconductor device can be greatly improved. That is, the technique disclosed in this embodiment is particularly useful when growing a silicon film of 100 μm or more. In this manufacturing method, the etching thickness ΔT1 in the etching step S4 is larger than the thickness ΔT2 of the silicon film 82 to be grown. Therefore, substantially all of the silicon film 80 grown on the surface of the susceptor 16 in the film forming step S6 can be removed in the etching step S4. Therefore, even if steps S4 to S8 are repeatedly performed, the silicon film 80 does not grow cumulatively on the surface of the susceptor 16. As described above, in the manufacturing method of the embodiment, since the silicon film 80 on the surface of the device in the chamber 15 can be removed, particles are generated from the silicon film 80 and formed on the silicon film 82 on the surface of the semiconductor wafer 50. It is possible to suppress problems such as adhesion of particles. According to the manufacturing method of this embodiment, a high-quality silicon film 80 can be obtained stably.

  In the above-described embodiment, the susceptor 16 (that is, the semiconductor wafer 50) is maintained at about 1200 ° C. in the etching process and the film forming process, but the temperature of the susceptor 16 may be within a range of 1100 ° C. to 1300 ° C. Any temperature may be used.

  In the above-described embodiment, the silicon film 80 on the surface of the susceptor 16 is completely removed in the etching process. However, depending on the gas flow and the shape of the susceptor 16, it may be difficult to remove all of the silicon film 80. In this case, it is preferable to remove the silicon film 80 on at least the mounting surface of the semiconductor wafer (that is, a plane continuous with the surface on which the semiconductor wafer is mounted). If the silicon film 80 on the mounting surface is removed, most of the problems caused by the silicon film 80 can be prevented.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

10: Semiconductor manufacturing device 15: Chamber 16: Susceptor 17a: Placement surface 17b: Opening 22: Heater 25: Gas supply device 26: Shower plate 29: Exhaust pump 50: Semiconductor wafer 80: Silicon film 82: Silicon film

Claims (5)

A method for manufacturing a semiconductor device, comprising:
Has disposed on a susceptor in a chamber, the operation of growing a film on the surface of the semiconductor wafer placed on the susceptor, and said film and semiconductor wafer placed on the susceptor etchable etching gas A loading step of placing a semiconductor wafer on a susceptor in a chamber of a semiconductor manufacturing apparatus capable of performing an operation to be introduced into the chamber;
A first etching step of etching the semiconductor wafer by introducing the etching gas into the chamber after the carrying-in step;
A first film forming step of growing a film on the surface of the semiconductor wafer in the chamber after the first etching step;
After the first film forming step, the semiconductor wafer is unloaded from the chamber , and another semiconductor wafer is disposed on the susceptor in the chamber;
A second etching step of etching the film on the surface of the semiconductor wafer and the susceptor by introducing the etching gas into the chamber after the replacement step;
A second film-forming step of growing a film on the surface of the semiconductor wafer in the chamber after the second etching step;
I have a,
In the replacement process, the cleaning process for removing the film formed on the surface of the susceptor is not performed after the semiconductor wafer is unloaded from the chamber until another semiconductor wafer is placed on the susceptor in the chamber. A featured manufacturing method.   The manufacturing method according to claim 1, wherein the etching thickness of the semiconductor wafer in the second etching step is larger than the thickness of the film grown in the first film forming step.   3. The manufacturing method according to claim 1, wherein in the first film forming step and the second film forming step, a film having a thickness of 100 μm or more is grown. The susceptor includes a mounting surface on which the semiconductor wafer is mounted ;
The manufacturing method according to any one of claims 1 to 3, wherein in the second etching step, etching is performed until at least the film grown on the mounting surface in the first film forming step is completely removed. The semiconductor wafer is a silicon wafer,
The film grown in the first film formation step and the second film formation step is a silicon film.
The manufacturing method as described in any one of Claims 1-4.

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