JP2011074466A - Film-forming apparatus and film-forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film-forming apparatus that covers a region in the vicinity of the jointed part of an electrode, that feeds an electric power to a heater when heating a silicon wafer of a substrate, and thereby can prevent the contamination. <P>SOLUTION: The film-forming apparatus 100 includes: a hoisting unit 133 for placing the silicon wafer 101 on a susceptor 110; the heater 121 for heating the silicon wafer 101; the electroconductive bus bar 123 which supports the heater 121; an electrode 107 which is fixed to the bus bar 123 and can feed an electric power to the heater 121; and a hollow column 105 which accommodates and supports the electrode 107 and a purge gas introduction pipe 135 that can supply a purge gas. The film-forming method includes: supplying the purge gas to the periphery of the jointed part from the purge gas introduction pipe 135 while covering the jointed part of the bus bar 123 with the electrode 107 with a tabular hoisting base 131 of the hoisting unit 133, by lowering the hoisting unit 133; and heating the substrate with the heater 121 while purging the peripheral region with the gas. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a film forming apparatus and a film forming method.

  Conventionally, an epitaxial growth technique has been utilized for manufacturing a semiconductor element that requires a relatively large crystal film, such as a power device such as an IGBT (Insulated Gate Bipolar Transistor). In order to manufacture an epitaxial wafer in which a single crystal film such as silicon is grown on a wafer as a substrate, a single wafer type film forming apparatus is often used.

FIG. 4 is a schematic cross-sectional view of a conventional film forming apparatus.
A conventional single-wafer type film forming apparatus 200 includes a chamber 201 which is a film forming chamber, a base 202 on which the chamber 201 is loaded, a reaction gas supply path 215 for supplying a reaction gas 204 into the chamber 201, and a film formation. Wafer heating means 205 that enables heating of the wafer 203 as the target substrate is provided. A hollow cylindrical column 206 extending upward into the chamber 201 is attached to the lower portion of the base 202.

  The wafer heating means 205 described above is attached to the upper end portion of the column 206. Two electrode rods 208 that are fixed to the column 206 are provided inside the column 206. The two electrode rods 208 extend through the upper end portion of the support column 206 to the wafer heating means 205 in the chamber 201.

  The wafer heating means 205 includes a heater 209 and a conductive booth bar 210 that holds the heater 209 fixedly. The booth bar 210 is fixed to a connecting member 211 fixed to the upper end portion of the support column 206. As a result, the heater 209 has a structure fixed to the support column 206. The two electrode rods 208 are connected to the connecting member 211, respectively. Therefore, power can be supplied to the heater 209 via the two electrode bars 208. The support 206 is further provided with an upper lid 212 for closing the upper surface portion.

  In the chamber 201, a wafer 203, which is a substrate to be deposited, is disposed, and a susceptor 220 for placing and holding the wafer 203 is provided. The susceptor 220 is rotatable as follows. That is, the hollow cylindrical support column 206 is provided with a hollow rotation shaft 221 so as to surround the periphery thereof, and this rotation shaft 221 is rotatably attached to the base 202 independently of the support column 206 by a bearing (not shown). It is attached and rotated by a separate motor 222.

  A rotating cylinder 223 is disposed at the upper end of the rotating shaft 221 extending to the inside of the chamber 201, and the above-described susceptor 220 is attached to the rotating cylinder 223. Therefore, the susceptor 220 is rotatably disposed above the wafer heating unit 205 and inside the chamber 201.

  In addition, elevating pins 230 that pass through the inside of the column 206 are disposed inside the column 206. And the lower end of the raising / lowering pin 230 is extended to the raising / lowering apparatus (not shown) which is provided under the support | pillar 206 and raises / lowers the raising / lowering pin 230. As shown in FIG. Then, the lifting / lowering pin 230 can be moved up or down by operating the lifting / lowering device.

  The elevating pins 230 are used when the wafer 203 loaded into the film forming apparatus 200 is placed on the susceptor 220 or when the wafer 203 after the film forming process is picked up from the susceptor 220 and taken out of the film forming apparatus 200. Used when

  That is, when carrying out the wafer 203 on the susceptor 220 after the film forming process from the film forming apparatus 200, the elevating pins 230 are provided at the upper side by using the upper end of the elevating pins 230 ascended by the elevating apparatus (not shown). It pushes up against the lower surface of the wafer 203 on the susceptor 220 and supports it from below. Then, the wafer 203 is further lifted, and the wafer 203 is separated from the susceptor 220, lifted, and delivered to a transfer robot (not shown). Then, the wafer 203 is carried out of the film forming apparatus 200 by the transfer robot.

  In addition, when the wafer 203 to be deposited is loaded into the deposition apparatus 200 and placed on the susceptor 220, the lifting pins 230 are loaded into the deposition apparatus 200 by a transfer robot (not shown). The processed wafer 203 is raised to a position where it can be received.

  The wafer 203 on the transfer robot is supported on the lower surface by the elevating pins 230 that are further raised by the elevating device, and lifted upward away from the transfer robot.

Thereafter, the transfer robot that has been emptied after delivering the wafer 203 moves out of the chamber 201 of the film forming apparatus 200.
On the other hand, the lift pins 230 are lowered to a position where the wafer 203 is in contact with and supported by the susceptor 220 while supporting the wafer 203.

  By returning the position supported on the susceptor 220 in this way, the wafer 203 is placed on the susceptor 220 at a position where a film forming reaction process can be performed. On the other hand, the elevating pin 230 is further lowered, and waits for the next work at a predetermined position as shown in FIG.

  And in the film-forming apparatus 200 provided with the above structure, the wafer 203 which is a board | substrate is rotated in the state mounted on the susceptor 220 after that. Then, while rotating, heating is performed by the heater 209 of the wafer heating means 205 provided below the susceptor 220. At this time, an epitaxial film is formed on the wafer 203 by supplying the reactive gas 204 through the reactive gas supply path 215.

During the vapor deposition, in the film forming apparatus 200, the temperature of the wafer 203 may be in a very high temperature exceeding 1000 ° C. due to the heater heating of the wafer heating means 205.
Patent Document 1 discloses a thin film growth apparatus provided with lift pins that slidably pass through a countersink portion of a susceptor and that lift and lower a substrate such as a wafer.

JP 2000-26192 A

  As described above, the chamber 201 is placed in a very high temperature environment when the wafer is heated during vapor deposition. Therefore, each part of the film forming apparatus 200 needs to be configured with a high heat resistant material.

  Therefore, as the material of each part constituting the wafer heating means 205, high-purity SiC or the like is used for the heater 209 having the highest temperature, and the SiC-coated carbon is used as the conductive booth bar 210 that supports the heater 209. Etc. are used as materials. These SiC materials and SiC-coated carbon are used because they are less likely to be contaminated during heating film formation, although they have problems such as being inferior in flexibility and being easily broken. On the other hand, although desirable in terms of flexibility and high heat resistance, a metal material that may be contaminated during heating film formation is not usually used as a constituent material of the wafer heating means.

  On the other hand, in the electrode rod 208 disposed inside the hollow cylindrical column 206, the ultimate temperature is slightly lower than that of the heater 209 and the vicinity thereof, so securing and improving the conductive performance are more important issues. Become. As a result, the electrode rod 208 is usually used as a homogeneous rod (rod-like body) using metallic molybdenum as a material. The molybdenum electrode rod 208 has excellent conductivity and rigidity. Similarly, a metal molybdenum material may be used for the connecting member 211 that connects the two electrode rods 208 and the booth bar 210.

  However, the electrode rod 208 is disposed inside the hollow cylindrical column 206 and has a temperature slightly lower than that of the heater 209 and its vicinity, but is about 700 to 800 ° C. or higher in the chamber 201. May be exposed to high temperature environment. As a result, impurities contained therein are released from the metal molybdenum constituting the electrode rod 208 and the connecting member 211, and the molybdenum itself is thermally decomposed to contaminate the substrate such as a wafer to be deposited. There was a case.

  Further, as described above, the conductive connecting member 211 made of, for example, metal molybdenum supports the conductive booth bar 210 that supports the heater 209, while being connected to the electrode rod 208. In this case, power can be supplied to the heater 209 via the electrode rod 208, but a gap is formed in the joint portion between the connecting member 211 and the booth bar 210 and the joint portion between the connecting member 211 and the electrode rod 208 when the heater is heated. There is.

  Regarding the formation of a gap at such a joining portion, the contribution of the booth bar 210 and the connecting member 211, and the booth bar 210 and the electrode rod 208 being made of different materials is large. That is, the booth bar 210 is made of, for example, carbon, and the connecting member 211 and the electrode rod 208 are made of metallic molybdenum. Due to the difference in thermal expansion coefficient of each material at the time of high-temperature heating during vapor phase film formation, for example, the booth bar 210 A gap may occur in the joint surface between 210 and the connecting member 211.

In that case, the reaction gas 204 may enter and react with the minute gaps that are formed, and by-product adhesion or corrosion may occur. As a result, the electrical resistance value rises at the above-mentioned joining portion, which causes factors such as shortening the maintenance interval of the wafer heating means 205 and the electrode rod 208, and shortening the life of the apparatus.

  Therefore, in order to prevent metal contamination of the substrate such as a wafer to be deposited, and to prevent adhesion or corrosion of by-products that may occur at the joint between the connecting member and the booth bar or electrode. However, conventional film forming apparatuses and film forming methods are insufficient, and a film forming apparatus and a film forming method having a new configuration are required.

  The present invention has been made in view of these points. That is, an object of the present invention is to provide a metal electrode or a connecting member thereof disposed in a hollow cylindrical column extending into a chamber that is a film forming chamber when a substrate such as a wafer to be formed is heated. It is an object of the present invention to provide a film forming apparatus having a mechanism for preventing contamination of a substrate such as a wafer that may occur due to the above.

  In addition, another object of the present invention is to react from the upper side where the pillars open in the vicinity of the joint portion between the booth bar and the connecting member and the joint portion between the connecting member and the electrode rod during film formation on a substrate such as a silicon wafer. An object of the present invention is to provide a film forming apparatus and a film forming method capable of preventing gas from entering and suppressing adhesion or corrosion of by-products.

  Other objects and advantages of the present invention will become apparent from the following description.

A first aspect of the present invention includes a film formation chamber,
A susceptor on which the substrate is placed in the deposition chamber;
A rotating cylinder that supports the susceptor at the top;
A heater provided inside the rotating cylinder, for heating the substrate, and a conductive booth bar for supporting the heater;
A rotating shaft provided at a lower portion of the film forming chamber to support and rotate the rotating cylinder;
A film-forming apparatus having a hollow cylindrical column provided inside the rotating shaft and containing an electrode for supplying power to the heater via a booth bar,
An elevating unit having a plate-like elevating base and a plurality of elevating pins erected on the elevating base is disposed inside the rotary cylinder,
Inside the column, a purge gas introduction pipe that is open at the top and capable of supplying purge gas is disposed,
Raise and lower the lifting unit, and place the substrate on the susceptor with the lifting pins,
The elevating unit is lowered to cover the space above the booth bar / electrode joint with the elevating base, and the purge gas is supplied from the purge gas introduction pipe to purge the area around the booth bar / electrode joint. It is what.

  And it is preferable that the continuous protrusion part is provided in the surrounding part of the lower surface of a raising / lowering base.

  And it is preferable that the groove | channel is provided in the booth bar by the position and shape corresponding to the projection part of the raising / lowering base lower surface which opposes.

  Moreover, it is preferable that the rotating cylinder is provided with a purge gas discharge portion capable of discharging gas in the vicinity of the bottom surface portion.

According to a second aspect of the present invention, a substrate is placed on a susceptor provided in a film forming chamber by using an elevating pin of an elevating unit that can be moved up and down, and a rotating cylinder on which the susceptor is arranged is formed in a film forming chamber. A reaction gas is formed in the film formation chamber while the substrate is heated by supplying power through a booth bar and an electrode supporting the heater to a heater disposed inside the rotating cylinder. Forming a film on the surface of the substrate by supplying
The elevator unit after the substrate is placed on the susceptor is lowered, the plate-like elevator base of the elevator unit is used to cover the space above the joint between the booth bar and the electrode, and the booth bar covered with the elevator base; The substrate is heated while supplying a purge gas around the electrode joint portion to form a gas purged state around the booth bar and the electrode joint portion.

  According to the first aspect of the present invention, when heating a substrate such as a wafer that is a film formation target, the electrode rod upper part and the connecting part of the connecting member constituting the electrode, and the peripheral region of the connecting part of the connecting member and the booth bar, It is possible to effectively separate from the substrate installation area such as the wafer in the heater installation atmosphere where the heater is installed. Therefore, there is provided a film forming apparatus that can prevent contamination of the substrate such as a wafer that may be caused by heating of the electrode rod or the connecting member during film formation on the substrate such as a wafer.

  According to the second aspect of the present invention, at the time of heating a substrate such as a wafer that is a film formation target, the electrode rod upper portion constituting the electrode and the joining portion of the connecting member and the peripheral region of the joining portion of the connecting member and the booth bar, It is possible to perform the film forming process on the substrate such as a wafer after the heater is installed and effectively separated from the substrate installation region such as the wafer in the heater installation atmosphere. Therefore, there is provided a film forming method capable of preventing contamination on the substrate such as a wafer that may be caused by heating of the electrode rod or the connecting member during film formation on the substrate such as a wafer.

It is typical sectional drawing of the film-forming apparatus of embodiment of this invention. It is a typical top view which shows an example of the raising / lowering unit of embodiment of this invention. It is typical sectional drawing of the rotation cylinder part of the film-forming apparatus of another embodiment of this invention. It is typical sectional drawing of the conventional film-forming apparatus.

  FIG. 1 is a schematic cross-sectional view of a film forming apparatus 100 according to an embodiment of the present invention. In this embodiment mode, a silicon wafer 101 is used as a film formation target substrate. However, the present invention is not limited to this, and a wafer made of another material may be used depending on the case.

  The film formation apparatus 100 includes a chamber 102 as a film formation chamber. A base 104 on which the chamber 102 is loaded is provided. A support 105 having a non-conductive and hollow cylindrical shape is attached to the lower surface side of the base 104 and extends upward into the chamber 102.

  A reaction gas supply path 103 for supplying a reaction gas 115 for forming a crystal film on the surface of the heated silicon wafer 101 is connected to the upper portion of the chamber 102. In the film formation apparatus 100 of this embodiment, trichlorosilane can be used as the reaction gas 115 and is introduced into the chamber 102 from the reaction gas supply path 103 in a state of being mixed with hydrogen gas as a carrier gas.

  At this time, a current plate (not shown) having an appropriate number of through holes (not shown) through which the reaction gas passes is provided upstream of the direction (arrow direction) in which the reaction gas flows with respect to the silicon wafer 101. It may be. The reaction gas supplied from the reaction gas supply path 103 flows down toward the silicon wafer 101.

  Inside the chamber 102, a susceptor 110 on which the silicon wafer 101 is placed is provided on a hollow rotating cylinder 111. The rotating cylinder 111 is supported by the rotating shaft 112 and is provided so as to surround the periphery of the hollow cylindrical column 105 extending from the lower surface of the base 104 into the chamber 102.

  The rotating shaft 112 is rotatably attached to the base 104 by a bearing (not shown) independently of the support column 105, and is rotated by a separate motor 113. That is, when the rotating shaft 112 rotates through the motor 113, the rotating cylinder 111 attached to the rotating shaft 112 rotates, and the susceptor 110 provided on the rotating cylinder 111 also rotates.

  Wafer heating means 120 is attached to the upper surface of a hollow cylindrical column 105 extending into the chamber 102. Note that the upper end of the column 105 is closed by an upper lid 106.

  The surface temperature of the silicon wafer 101 that changes due to heating and the temperature of the susceptor 110 on which the silicon wafer 101 is placed are measured by a radiation thermometer (not shown) provided in the upper part of the chamber 102. For this reason, it is preferable that the chamber 102 and a necessary baffle plate (not shown) are made of quartz. Thereby, temperature measurement by a radiation thermometer (not shown) can be prevented from being hindered by the chamber 102 and the current plate (not shown). The measured temperature data is sent to a control device (not shown).

  A control device (not shown) controls the operation of a three-way valve (not shown) provided in the hydrogen gas flow path. That is, when the silicon wafer 101 reaches a predetermined temperature or higher, a control device (not shown) moves a three-way valve (not shown) to control the supply amount of hydrogen gas to the chamber 102. A control device (not shown) also controls the output of the heater 121.

  As for the shape of the upper surface of the column 105, as shown in FIG. 1, a shape in which the cylindrical shape of the column 105 is combined with a donut-shaped disk with a hole, that is, a shape having a protruding portion protruding from the cylindrical member. Alternatively, a flange shape may be used, and an edge that rises upward may be provided around the protruding portion. Since the upper end portion of the support column 105 has such a shape, the attachment of the wafer heating means 120 described below can be made more reliable.

  Two electrodes 107 are provided inside the hollow cylindrical column 105. Each of these electrodes 107 includes a uniform rod-shaped metal molybdenum (Mo) electrode rod 108 and a connecting member 124 that is fixed to the upper end portion of the electrode rod 108 and supports a booth bar 123 described later.

  The connecting member 124 of the electrode 107 has a shape extending from the upper end portion of the electrode rod 108 in the circumferential direction of the support column 105. Therefore, the electrode 107 has a shape bent as an L shape as a whole. That is, the electrode rod 108 and the connecting member 124 are L-shaped electrodes. The connecting member 124 is made of metallic molybdenum, and the electrode 107 bent in an L shape is made of metallic molybdenum as a whole.

  The wafer heating means 120 includes a heater 121 that heats the silicon wafer 101 and an arm-shaped booth bar 123 that fixes and supports the heater 121. At this time, the booth bar 123 is supported by the connecting member 124 at the end opposite to the side supporting the heater 121. The booth bar 123 is fixed and integrated with the connecting member 124 by bolting using the bolt 126.

  The heater 121 is made of silicon carbide (SiC), and the two arm-shaped booth bars 123 that support the heater 121 are conductive, for example, made of a carbon material coated with SiC. As described above, the connecting member 124 is made of metal molybdenum in the same manner as the electrode rod 108. Therefore, power can be supplied from the electrode 107 to the heater 121 via the booth bar 123.

  The wafer heating means 120 can be provided with an out-heater between the heater 121 and the susceptor 110 on the back side of the susceptor 110. By this outheater, the peripheral edge of the silicon wafer 101 and the susceptor 110 can be mainly heated. Thus, when two types of heaters are provided to heat the silicon wafer 101, the uniformity of the temperature distribution in the surface of the silicon wafer 101 can be improved.

  In this case, after the silicon wafer 101 is placed on the susceptor 110 in the chamber 102, the silicon wafer 101 is uniformly heated by the coordinated heating of the heater 121 and the outheater, and a predetermined film forming process can be performed.

  Next, as shown in FIG. 1, in the fixed and integrated booth bar 123 and the connecting member 124, the lower surface of the connecting member 124 protrudes so as to protrude from the upper surface of the column 105, that is, the cylindrical member of the column 105. It is in contact with at least a part of the upper surface of the portion. Further, at least one of the booth bar 123 and the connecting member 124 is also in contact with the edge of the upper surface of the support column 105 described above, and is configured to be fixed to the support column 105 by supporting at least two points.

Next, a particularly characteristic lifting unit 133 in the film forming apparatus 100 according to the embodiment of the present invention will be described.
In the film forming apparatus 100 according to the present embodiment, an elevating bar 132 that passes through the upper lid 106 and penetrates the support column 105 and the elevating bar 132 are provided inside the rotating cylinder 111 in the chamber 102 and the rotating shaft 112 that supports the rotating cylinder 111. A lifting unit 133 including a plate-like lifting base 131 provided at an upper end portion of the base plate and a plurality of lifting pins 130 standing on the periphery of the upper surface of the lifting base 131 is disposed.

For example, each part of the lifting unit 133 is made of a material that does not release impurities that contaminate the silicon wafer 101 that is a film formation target even when exposed to a high temperature exceeding 1000 ° C., specifically, silicon dioxide ( It is desirable to use SiO ₂ ), silicon carbide (SiC), SiC-coated carbon (C), or the like.

  And the lower end of the raising / lowering rod 132 of the raising / lowering unit 133 is extended to the raising / lowering apparatus (not shown) which is provided under the support | pillar 105 and controls raising / lowering of the raising / lowering rod 132. As shown in FIG.

  That is, in the film forming apparatus 100 according to the embodiment of the present invention, the elevating device (not shown) is operated to raise or lower the elevating rod 132, and as a result, the elevating unit 133 is raised or lowered to raise and lower the elevating base. The elevating pin 130 standing on 131 can be raised or lowered.

  It should be noted that when the elevator unit 133 is moved up and down, the installation position is taken into consideration so that the lift pins 130 of the lift unit 133 do not contact the heater 121. Further, as described above, when the wafer heating means 120 also has an outheater, the elevating pins 130 are arranged so that the outheater and the elevating pins 130 are not in contact with each other.

  The elevating base 131 of the elevating unit 133 and the elevating pins 130 provided on the elevating unit 133 are used when the silicon wafer 101 carried into the film forming apparatus 100 is placed on the susceptor 110 or after the film forming process. This is used when picking up 101 from the susceptor 110 and carrying it out of the film forming apparatus 100.

  That is, when the silicon wafer 101 on the susceptor 110 after film formation is unloaded from the film formation apparatus 100, the lift pins 130 are lifted by the entire lift unit 133 being lifted by a lift apparatus (not shown), and the top end portion thereof Is pushed up in contact with the lower surface of the silicon wafer 101 on the susceptor 110 provided above and supported from below. Then, the silicon wafer 101 is further lifted, lifted and separated from the susceptor 110, and delivered to a transfer robot (not shown) waiting in the chamber 102. Thereafter, the silicon wafer 101 is carried out of the film forming apparatus 100 by a transfer robot.

  In addition, when the silicon wafer 101 to be deposited is carried into the deposition apparatus 100 and placed on the susceptor 110, the lifting unit 133 is raised and the deposition apparatus 100 is moved by a transfer robot (not shown). The elevating pins 130 are raised to a position where the silicon wafer 101 carried in is received.

  Then, the silicon wafer 101 supported by the transfer robot (not shown) and carried into the chamber 102 of the film forming apparatus 100 is held on the lift pins 130 while being supported on the transfer robot. Keep it. Thereafter, the elevating unit 133 is further raised by an elevating device (not shown), and the elevating pins 130 support the silicon wafer 101 on the transfer robot from the lower surface. Then, it is pushed up and lifted upward, and separated from the transfer robot so that it is supported by the lift pins 130.

Thereafter, the transfer robot (not shown) that has been emptied after delivering the silicon wafer 101 moves out of the chamber 102 of the film forming apparatus 100.
On the other hand, the elevating unit 133 descends while the silicon wafer 101 is supported by the elevating pins 130 and continues to descend to a position where the silicon wafer 101 contacts and is supported by the susceptor 110.

The silicon wafer 101 thus carried into the chamber 102 is placed on the susceptor 110 at a position where a film forming reaction process can be performed.
Then, as shown in FIG. 1, after the silicon wafer 101 is placed on the susceptor 110, the elevating unit 133 is further lowered, and at a predetermined position during the film forming operation using the reaction gas 115 on the silicon wafer 101. Wait until the next silicon wafer 101 is unloaded.

  FIG. 2 is a schematic plan view showing an example of the lifting unit according to the embodiment of the present invention. The lifting unit 133 ′ shown in FIG. 2 has a configuration in which three lifting pins 130 ′ are erected on the periphery of the upper surface of a disk-shaped lifting base 131 ′. In FIG. 2, the rotary cylinder 111 is also shown so that the positional relationship between the rotary cylinder 111 and the lifting unit 133 can be understood.

  As shown in FIG. 1, during this film forming operation, the lifting unit 133 is such that the lower surface of the disk-shaped lifting base 131 does not contact the head of the bolt 126 that fixes the lower portion of the booth bar 123 and the connecting member 124. Wait at a slightly higher position. The upper portion of the electrode base 108 constituting the electrode 107 and the joining portion of the connecting member 124 and the region on the lower surface side of the lifting base 131 including the periphery of the joining portion of the connecting member 124 and the booth bar 123 can be covered. That is, it can serve as a lid that separates a region where the silicon wafer 101 is placed above the lifting base 131 and a lower region including the joint portion of the electrode 107.

  At this time, an annular continuous protrusion 137 is provided on the peripheral portion of the lower surface of the elevating base 131. Therefore, when the elevating unit 133 is lowered, the elevating base 131 uses the protrusion 137 on the lower surface of the elevating base 131 to connect the upper portion of the electrode bar 108 and the connecting member 124 and the connecting portion of the connecting member 124 and the booth bar 123. It is possible to cover efficiently.

  On the other hand, in the lower part of the booth bar 123 facing the protrusion 137 on the lower surface of the elevating base 131, a groove is formed as a correspondingly shaped recess. Since this concave groove is provided, it is avoided that the elevating unit 133 and the booth bar 123 contact each other when the elevating unit 133 is lowered. And it installs in the sky a little apart from the booth bar 123 as a lid | cover which isolate | separates the area | region where the silicon wafer 101 above the raising / lowering base 131 mentioned above and the area | region containing the junction part of the electrode 107 are isolate | separated.

  Further, a purge gas introduction pipe 135 that passes through the upper lid 106 and opens at the top is disposed inside the support column 105. The purge gas introduction pipe 135 can be supplied with a purge gas from its lower opening. Therefore, the purge gas can be introduced into the lower surface side region of the lift base 131 of the lift unit 133 through the upper opening portion, and the atmosphere in that region can be purged. At this time, the protrusions 137 provided on the peripheral edge of the lower surface of the elevating base 131 serve as a barrier, and the gas purge of the region including the joint portion of the electrode 107 can be performed effectively.

  That is, the elevating base 131 is installed above the booth bar 123, and purge gas is supplied to the lower surface side area of the elevating base 131, so that the elevating base 131 is connected to the lower surface side of the elevating base 131 and the upper part of the electrode rod 108 constituting the electrode 107. The joining portion of the member 124 and the surrounding region of the joining portion of the connecting member 124 and the booth bar 123 can be effectively separated from the region in which the heater 121 is installed and in the heater installation atmosphere.

  Further, in this case, even if purge gas is introduced below the heater 121, the effect does not reach the heater 121, and heater heating is not hindered.

  It should be noted that, as described above, the region where the upper portion of the electrode rod 108 constituting the electrode 107 and the connecting member 124 and the peripheral portion of the connecting portion of the connecting member 124 and the booth bar 123 are in the heater installation atmosphere with the heater 121 installed. In order to separate the two, it is also possible to provide a separation plate that partitions the two regions. However, it becomes necessary to provide a separating plate for the partition. Therefore, the film forming apparatus 100 according to the present embodiment has the elevating unit 133 that already has the function of the separation plate, and can achieve the desired performance without increasing the number of parts.

  Further, the purge gas introduced into the rotary cylinder 111 using the purge gas introduction pipe 135 does not reach the silicon wafer 101 during film formation due to the effect of the lifting base 131 of the lifting unit 133 as described above. It is discharged into the chamber 102. Thereafter, the gas is exhausted to the outside of the chamber 102 together with the source gas through a gas exhaust unit (not shown) in the chamber 102. Therefore, it is desirable that the rotary cylinder 111 is provided with an appropriate gas discharge port.

  FIG. 3 is a schematic cross-sectional view showing the structure of a rotating cylinder portion of a film forming apparatus according to another embodiment of the present invention. In the film forming apparatus of another embodiment shown in FIG. 3, a purge gas discharge unit 136 is provided in the vicinity of the bottom surface of the rotating cylinder 111 ′. The purge gas introduced from the purge gas introduction pipe (not shown) into the rotary cylinder 111 ′ by the purge gas discharge unit 136 does not reach the heater 121 ′ during heating or the silicon wafer 101 ′ during film formation. It is discharged into a chamber (not shown).

  Further, the supply of the purge gas to the purge gas introduction pipe 135 is similarly controlled by the control device (not shown) that controls the supply amount of the hydrogen gas to the chamber 102 described above. Therefore, the hydrogen gas used as the carrier gas for the reaction gas 115 can be used as the purge gas. It is also possible to supply an inert gas such as nitrogen gas or argon gas from a purge gas supply source (not shown) separately provided for the purge gas under the control of the control device (not shown).

  That is, when a silicon crystal film is formed on a substrate, it is desirable to use hydrogen gas or nitrogen gas as a purge gas. When a SiC crystal film having a film formation temperature of about 1600 ° C. is formed, it is preferable to use a less reactive argon gas as the purge gas. In addition, when depositing gallium nitride (GaN), hydrogen gas is preferably used as a purge gas.

  As described above, the lifting base 131 covers the region on the lower surface side of the lifting base 131 that includes the upper part of the electrode rod 108 constituting the electrode 107 and the joining part of the connecting member 124 and the periphery of the joining part of the connecting member 124 and the booth bar 123. In the film forming apparatus 100 of the present embodiment, the bonding member 124 and the booth bar 123 are joined at the time of film formation on the substrate such as the silicon wafer 101 by supplying the purge gas from the purge gas introduction pipe 135 to the region. It is possible to prevent the joint portion between the portion and the connecting member 124 and the electrode rod 108 from being exposed to the reaction gas 115.

  As a result, it is possible to prevent the reaction gas 115 from entering the bonding portion between the connecting member 124 and the booth bar 123 and the bonding portion between the connecting member 124 and the electrode rod 108 during film formation on the silicon wafer 101. In the film forming apparatus 100, it is possible to suppress adhesion of by-products, corrosion, and the like at the joint portion between the connecting member 124 and the booth bar 123 and the joint portion between the connecting member 124 and the electrode rod 108.

  Furthermore, the electrode rod 108 is disposed inside the hollow cylindrical column 105 and has a temperature that is slightly lower than that of the heater 121 and its vicinity, but is about 700 to 800 ° C. or higher in the chamber 102. May be exposed to high temperature environment. As a result, impurities contained therein may be released from the metal molybdenum constituting the electrode rod 108, or the molybdenum itself may be thermally decomposed to contaminate a substrate such as a wafer to be deposited. there were.

  Therefore, by supplying the purge gas from the purge gas introduction pipe 135, the discharged impurities and the like are discharged into the chamber 102 together with the purge gas while not reaching the silicon wafer 101, and without contaminating the silicon wafer 101, It is possible to discharge out of the chamber 102.

  Furthermore, by supplying the purge gas from the purge gas introduction pipe 135, it is possible to control the electrode rod 108 and the connecting member 124 that have risen in temperature during film formation heating so that the temperature is not increased. That is, the upper portion of the electrode rod 108 and the connecting member 124 are cooled by supplying the purge gas, and the temperature is set to a temperature at which impurities are not released from the electrode rod 108 and the connecting member 124 made of molybdenum, specifically 700 ° C. to 800 ° C. It is also possible to control to the extent that it does not reach.

Next, the film forming method of the present invention will be described.
Formation of the silicon epitaxial film on the silicon wafer 101 is performed as follows. The silicon wafer 101 can be a 300 mm silicon wafer used for applications such as power semiconductors.

  First, the silicon wafer 101 is carried into the chamber 102 using a transfer robot (not shown). After the carry-in, the silicon wafer 101 is placed at the carry-in position of the substrate in the chamber 102 while being supported by the transfer robot.

Next, after the silicon wafer 101 is carried in, heating is performed using the wafer heating means 120, and after the temperature of the susceptor 110 reaches a specified temperature that is 200 ° C. to 300 ° C. lower than a predetermined film forming temperature on the silicon wafer 101, the wafer is moved up and down. Activate the device (not shown).
That is, the elevating unit 133 disposed at the standby position is started to rise by an elevating device (not shown).

  The silicon wafer 101 is supported from the lower surface by the lift pins 130 of the lift unit 133. Then, the silicon wafer 101 is pulled away from the transfer robot and lifted further upward. Thus, the silicon wafer 101 is received from the transfer robot so that the silicon wafer 101 is supported only by the lift pins 130.

  Thereafter, the transfer robot that has been emptied after delivering the silicon wafer 101 is moved out of the chamber 102. Then, the lifting unit 133 that has received the silicon wafer 101 is lowered while the silicon wafer 101 is supported by the lifting pins 130.

  The lift unit 133 is lowered to a position where the silicon wafer 101 is in contact with and supported by the susceptor 110 while the silicon wafer 101 is supported by the lift pins 130.

The silicon wafer 101 thus carried into the chamber 102 is placed on the susceptor 110 at a position where a film forming reaction process can be performed.
Then, as shown in FIG. 1, the elevating unit 133 is further lowered and waits until the next silicon wafer 101 is unloaded at a predetermined position during the film forming operation using the reaction gas 115 on the silicon wafer 101.

  Next, the silicon wafer 101 is placed on the susceptor 110 and attached to the rotating cylinder 111, and the silicon wafer 101 is rotated at about 50 rpm.

  Next, the silicon wafer 101 is heated to a higher temperature by controlling the heater 121 as a heating means. For example, the film is gradually heated to a film forming temperature of 1150 ° C. After confirming that the temperature of the silicon wafer 101 has reached 1150 ° C. by measurement with a radiation thermometer (not shown), the rotational speed of the silicon wafer 101 is gradually increased. Then, the reaction gas 115 is caused to flow down from the reaction gas supply path 103 onto the silicon wafer 101 via a rectifying plate (not shown). Thus, an epitaxial layer of silicon having a uniform thickness is grown on all the silicon wafers 101.

  At this time, for example, in a power semiconductor application, a thick film having a thickness of 10 μm or more, most often about 10 μm to 100 μm, is formed on a 300 mm silicon wafer. In order to form a thick film, it is preferable to rotate the silicon wafer 101 during film formation. And it is good to make the rotation speed of the silicon wafer 101 high, for example, it is good to set it as the rotation speed of about 900 rpm.

  As the above-described heating of the silicon wafer 101 by the heater 121 is started, the purge gas to the purge gas introduction pipe 135 provided inside the column 105 is controlled by a control device (not shown). Start supplying. As the purge gas, hydrogen gas which is a carrier gas of the reaction gas 115 is used.

  Then, by supplying the purge gas using the purge gas introduction pipe 135, the purge gas is introduced into the lower surface side region of the lift base 131 of the lift unit 133, and the atmosphere in the region is purged. At this time, the protrusions 137 provided on the peripheral edge of the lower surface of the elevating base 131 serve as a barrier, and the gas purge of the region including the joint portion of the electrode 107 can be performed effectively. At this time, even if purge gas is introduced below the heater 121, the effect does not reach the heater 121, and heater heating is not hindered.

  On the other hand, the upper part of the electrode rod 108 and the connecting member 124 are cooled by supplying the purge gas, and the temperature is set such that impurities are not released from the electrode rod 108 and the connecting member 124 made of metal molybdenum. It is possible to control the temperature so as not to reach 700 ° C. to 800 ° C.

  After the epitaxial film having a predetermined thickness is formed on the silicon wafer 101, the supply of the reaction gas 115 is terminated. The supply of the carrier gas can also be terminated upon completion of the supply of the reaction gas 115, but is terminated after confirming that the silicon wafer 101 has become lower than a predetermined temperature by measurement with a radiation thermometer (not shown). You may make it do. Then, after the temperature of the silicon wafer 101 reaches a predetermined temperature, for example, 700 ° C. to 800 ° C., the supply of the purge gas to the region including the joint portion of the electrode 107 using the purge gas introduction pipe 135 is finished.

After that, it is confirmed that the silicon wafer 101 has been cooled to a predetermined temperature, and the lifting device (not shown) is operated again.
That is, the elevating unit 133 disposed at the standby position is started to rise by an elevating device (not shown).

  The silicon wafer 101 on the susceptor 110 is brought into contact with the tip of the lift pin 130 of the lift unit 133 from the lower surface side and supported from below. Further, the lifting / lowering unit 133 is raised, the silicon wafer 101 is lifted from the susceptor 110, separated, and delivered to a transfer robot (not shown) that enters the chamber 102 and stands by. Thereafter, the silicon wafer 101 after the film formation process is carried out of the chamber 102 of the film formation apparatus 100 by the transfer robot.

  At this time, the lifting unit 133 is lifted to cover the upper part of the electrode rod 108 constituting the electrode 107 and the joining portion of the connecting member 124 and the region including the periphery of the joining portion of the connecting member 124 and the booth bar 123. The elevating base 131 will also rise. As a result, the upper portion of the electrode rod 108 constituting the electrode 107 and the connecting portion of the connecting member 124 and the connecting portion of the connecting member 124 and the booth bar 123 are exposed. As a result, the state where the upper part of the electrode rod 108 and the connecting part 124 constituting the electrode 107 and the surrounding area of the connecting part of the connecting member 124 and the booth bar 123 are separated from the area where the heater 121 is installed and in the heater installation atmosphere. Will be resolved.

However, as described above, the lifting unit 133 is lifted after confirming that the silicon wafer 101 has been cooled to a predetermined temperature, for example, 500 ° C. or lower. Therefore, even if the reaction gas 115 enters the joining portion between the connecting member 124 and the booth bar 123 and the vicinity of the joining portion between the connecting member 124 and the electrode rod 108, the temperature reaches a temperature lower than the reaction temperature, that is, 700 ° C to 800 ° C. By-products do not adhere to the joined portions that have reached the temperature, and corrosion does not occur.
Similarly, the impurities contained therein are not released from the molybdenum metal constituting the sufficiently cooled electrode rod 108 or the like, and the molybdenum itself does not thermally decompose.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the first embodiment, an epitaxial growth apparatus is used as an example of a film forming apparatus, but the present invention is not limited to this. Any other film forming apparatus may be used as long as it supplies a reactive gas into the film forming chamber and heats the substrate placed in the film forming chamber to form a film on the surface of the substrate.

100, 200 Film forming apparatus 101 Silicon wafer 102, 201 Chamber 103, 215 Reactive gas supply path 104, 202 Base 105, 206 Prop 106, 212 Upper lid 107 Electrode 108, 208 Electrode rod 110, 220 Susceptor 111, 223 Rotary cylinder 112, 221 Rotating shaft 113, 222 Motor 115, 204 Reactive gas 120, 205 Wafer heating means 121, 209 Heater 123, 210 Booth bar 124, 211 Connecting member 126 Bolt 130, 230 Lifting pin 131 Lifting base 132 Lifting rod 133 Lifting unit 135 Introduction of purge gas Pipe 136 Purge gas discharge part 137 Projection part 203 Wafer

Claims (5)

A deposition chamber;
A susceptor on which a substrate is placed in the film formation chamber;
A rotating cylinder that supports the susceptor at the top;
A heater provided inside the rotating cylinder, for heating the substrate, and a conductive booth bar for supporting the heater;
A rotating shaft provided at a lower portion of the film forming chamber to support and rotate the rotating cylinder;
A film-forming apparatus having a hollow cylindrical column provided inside the rotating shaft and containing an electrode for supplying power to the heater via the booth bar,
An elevating unit having a plate-like elevating base and a plurality of elevating pins erected on the elevating base is disposed inside the rotating cylinder,
Inside the column, a purge gas introduction pipe that is open at the top and capable of supplying purge gas is disposed,
Raising and lowering the lifting unit, placing the substrate on the susceptor by the lifting pins,
The elevating unit is lowered to cover the space between the booth bar and the electrode by the elevating base, and purge gas is supplied from the purge gas introduction pipe to purge the area around the booth bar and the electrode. A film forming apparatus configured as described above.   The film forming apparatus according to claim 1, wherein a continuous protrusion is provided on a peripheral portion of the lower surface of the elevating base.   3. The film forming apparatus according to claim 1, wherein the booth bar is provided with a concave groove at a position and shape corresponding to a protruding portion of the lower surface of the ascending / descending base.   The film forming apparatus according to any one of claims 1 to 3, wherein the rotary cylinder is provided with a purge gas discharge portion capable of gas discharge in the vicinity of a bottom surface portion. A rotating shaft provided on the lower part of the film forming chamber is provided with a rotating cylinder in which the substrate is placed on the susceptor provided in the film forming chamber by using an elevating pin of an elevating unit capable of moving up and down, and the susceptor is arranged on the upper part. The substrate is heated by supplying power through a booth bar and electrodes that support the heater to the heater disposed inside the rotating cylinder to heat the substrate while supplying the reaction gas into the film formation chamber. A film forming method for forming a film on the surface of
The elevator unit after the substrate is placed on the susceptor is lowered, the plate-like elevator base of the elevator unit is used to cover the space above the booth bar and the electrode, and the elevator base The substrate is heated while supplying a purge gas around the junction between the booth bar and the electrode covered with gas to form a gas purged state around the junction between the booth bar and the electrode. A film forming method.

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