JP2005116565A - Substrate processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce poor substrate processing by detecting elastic deformation of a substrate caused when the substrate sent to a container is heated to a target temperature. <P>SOLUTION: A substrate processing apparatus comprises a susceptor 217 for holding a wafer 200 sent to the container 223, a heater 207 for heating the wafer 200 held by the susceptor 217, controlling means 54 for controlling the power supplied to the heater 207 from a power supply 52, a radiation thermometer 56 for detecting the temperature of the wafer or the susceptor 217, and a controller 55 which controls a power controlling means 53 so that the detected temperature may become a set one. In the controller 55, an allowable deviation value of power which is allowed for the detected temperature to become the set one is set when there is no warping occurring in the wafer 200 during heating of the wafer. Monitoring the power supplied to the heater 207, the controller 55 determines that there is warping occurring in the wafer when the monitored power exceeds the allowable deviation value, and outputs an abnormality signal. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a substrate processing apparatus, and more particularly to a substrate processing apparatus capable of detecting elastic deformation of a substrate during substrate heating.

The substrate processing apparatus is provided with a substrate heating control system for heating the substrate. FIG. 5 is a schematic configuration diagram of such a substrate heating control system.
The configuration of the substrate heating control system includes a heating body 1 for heating the substrate, a temperature detection unit 2 for detecting the substrate temperature, and an A / D conversion for converting the detected temperature (analog signal) from the temperature detection unit 2 into a digital signal. 3, controller 4 that outputs a power setting signal based on the difference between the detected temperature and the substrate target temperature (set temperature), control means 5 that determines the phase control amount based on the power setting signal from controller 4, and control means The power supply means 6 supplies power from the power source 7 to the heating body 1 in accordance with the phase control amount from 5.

  The operation of the thus configured substrate heating control system will be described. A preset temperature is set in the controller 4 in advance. The set temperature is determined by the thin film formation and heat treatment contents of the substrate. The temperature detecting means 2 detects the temperature of the substrate held on a susceptor (not shown) as a substrate holding means in the substrate processing chamber. The controller 4 applies a power setting signal to the control means 5. The control means 5 calculates the supply power required to raise the temperature of the heating element 1 to the set temperature from the difference between the set temperature and the detected temperature, and outputs a phase control signal corresponding to the phase control amount obtained by the calculation. Add to 6. The power supply means 6 to which the phase control signal is applied supplies the heating body 1 with the set power controlled by the phase control amount. The controller 4 has a feed hack circuit that maintains the set temperature after heating the substrate to the set temperature.

However, the substrate may be elastically deformed due to non-uniform substrate temperature, so-called warpage, during the substrate heat treatment process. In particular, in the case where a substrate is held on a substrate holding plate as a substrate holding means and the substrate is heated via the substrate holding plate, the spatial distance between the substrate on the substrate holding plate and the substrate holding plate is not improved by this deformation. It becomes uniform, and the state of heat inflow and outflow to the substrate becomes non-uniform. This phenomenon causes further elastic deformation, resulting in more uneven substrate temperature.
Thus, conventionally, the shape of the substrate holding plate has been devised, or a temperature bias or the like is intentionally applied when the substrate is heated to suppress the occurrence of elastic deformation.

  However, in the above-described prior art in which the shape of the substrate holding plate is devised or a temperature bias is intentionally applied when the substrate is heated, the frequency of occurrence of substrate elastic deformation depends on the pattern on the substrate or the thermal history of the substrate However, the elastic deformation of the substrate could not be sufficiently prevented. In addition, when the elastic deformation of the substrate cannot be prevented, it is necessary to use a person to find a defective substrate. The detection of defective substrates depends on the shape and production form of each device, but in ordinary semiconductor device factories, substrate sampling inspection is performed in the middle of several hundred processing steps. Will be discovered.

  The above-described substrate processing due to temperature non-uniformity causes a film thickness non-uniformity, a foreign matter defect and the like, resulting in a decrease in yield. Further, the substrate processing during the elastic deformation causes troubles such as generation of foreign matters in the processing chamber. This is because the film formed on the substrate peels off due to elastic deformation of the substrate, resulting in generation of foreign matter, or in the case of thermal CVD, the film forming gas itself grows in granular form by processing at a predetermined temperature or lower. There is a case.

  An object of the present invention is generated by elastic deformation of a substrate when heating the substrate by detecting the elastic deformation of the substrate when the substrate or the substrate holding means is heated to a set temperature by solving the above-described problems of the prior art. An object of the present invention is to provide a substrate processing apparatus capable of reducing defective substrate processing.

  According to a first aspect of the present invention, there is provided a container for containing a substrate, a substrate holding means for holding the substrate accommodated in the container, a heating means for heating the substrate held by the substrate holding means, and a power source for the heating means. Power control means for controlling the power supplied from the apparatus, temperature detection means for detecting the temperature of the substrate or the substrate holding means, detection temperature detected by the temperature detection means, and the preset substrate or the substrate holding means. A controller that controls the power control means so that the detected temperature becomes a set temperature by comparing with a set temperature, and the controller causes the substrate held by the substrate holding means to undergo elastic deformation during heating. In the case where the power supply means does not exist, an allowable upper limit value or lower limit value of power supplied from the power control means to the heating means is preset, and the power supply means supplies the heating means. The power of the substrate is monitored, the monitor power is compared with the upper limit value or the lower limit value, and an abnormal signal is output when the monitor power exceeds the upper limit value or the lower limit value. It is.

  When elastic deformation (warping) occurs in the substrate and a part of the substrate is separated from the substrate holding means, the total amount of heat transferred between the substrate holding plate and the substrate varies. This variation greatly affects the amount of power supplied to the heating means. That is, when the substrate is warped, the temperature of a part of the substrate is lowered. Further, the temperature of the corresponding part of the substrate holding means corresponding to a part of the substrate rises. For this reason, when the temperature detection means detects the temperature of the substrate, the controller controls the power supply means so as to raise the temperature of the substrate, and supplies larger electric power to the heating means. Further, when the temperature detection means detects the temperature of the substrate holding means, the controller controls the power supply means so as to lower the temperature of the substrate holding means so as to supply smaller power to the heating means. become. This power is monitored by the controller, and the controller outputs an abnormal signal when the monitored power exceeds the power upper limit value or the power lower limit value. Therefore, it can be determined whether or not the substrate is warped based on the presence or absence of an abnormal signal.

  A second invention is the substrate processing apparatus according to the first invention, wherein the power supply means controls the power supply amount by phase control by a thyristor. Since the amount of power supply can be controlled by phase control, the time until the temperature of the substrate or the substrate holding means is raised to the set temperature can be shortened.

  According to a third invention, in the first or second invention, the heating means is disposed in each of the zones divided into a plurality of zones at positions facing the substrate via the substrate holding means, and the power supply The means is a substrate processing apparatus which is controlled independently for each zone. Since the temperature of the substrate or the substrate holding means can be controlled independently in each zone, the in-plane temperature of the substrate or the substrate holding means can be made uniform. .

  A fourth invention is a substrate processing apparatus according to any one of the first to third inventions, wherein the abnormal signal is added to an alarm output means for outputting an alarm. Since an abnormality signal is used to sound an alarm sound or buzzer sound, or an alarm is displayed to notify the occurrence of a failure, the substrate processing abnormality can be reliably notified to the operator.

  According to a fifth invention, in the first to fourth inventions, the heating power is preheated before the main heating for processing the substrate, and the monitor power is set to a power upper limit during the preheating. The substrate processing apparatus is characterized by being compared with a value or a power lower limit value. Abnormalities can be known at the preheating stage before the substrate is fully heated.

  According to a sixth aspect of the present invention, in the first to fifth aspects of the present invention, the heating power is overheated before the substrate is preheated by the heating means, and the monitor power is set to a power upper limit value or a power lower limit value during the overheating. A substrate processing apparatus characterized in that comparison is made. Abnormalities can be known before entering the preheating step.

  A seventh invention is the substrate processing apparatus according to any one of the first to sixth inventions, wherein the temperature of the substrate or the substrate holding means is detected using a radiation thermometer. When a radiation thermometer is used, the temperature of the substrate can be detected without contact.

  According to the present invention, it is possible to detect elastic deformation of the substrate during substrate heating, thereby reducing substrate processing defects.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In FIG. 3, an outline of a substrate processing apparatus to which the present invention is applied will be described.
In the substrate processing apparatus to which the present invention is applied, a FOUP (front opening unified pod) is used as a carrier for transporting a substrate such as a wafer. Further, in the following description, front, rear, left and right are based on FIG. That is, with respect to the paper surface shown in FIG. 3, the front is below the paper surface, the back is above the paper surface, and the left and right are the left and right of the paper surface.

  As shown in FIG. 3, the substrate processing apparatus includes a first transfer chamber 103 configured in a load lock chamber structure that can withstand a pressure (negative pressure) less than atmospheric pressure such as a vacuum state. A casing 101 of the transfer chamber 103 is formed in a box shape having a hexagonal shape in plan view and closed at both upper and lower ends. The first transfer chamber 103 is provided with a first wafer transfer device 112 that transfers two wafers 200 simultaneously under a negative pressure. The first wafer transfer device 112 is configured to be moved up and down by an elevator 115 while maintaining the airtightness of the first transfer chamber 103.

  The two side walls located on the front side of the six side walls of the housing 101 are connected to the carry-in spare chamber 122 and the carry-out spare chamber 123 via gate valves 244 and 127, respectively. Each has a load lock chamber structure that can withstand negative pressure. Further, a substrate placing table 140 for loading / unloading chamber is installed in the spare chamber 122, and a substrate placing table 141 for unloading chamber is installed in the spare chamber 123.

  A second transfer chamber 121 used at substantially atmospheric pressure is connected to the front sides of the reserve chamber 122 and the reserve chamber 123 via gate valves 128 and 129. In the second transfer chamber 121, a second wafer transfer machine 124 for transferring two wafers 200 at the same time is installed. The second wafer transfer device 124 is configured to be moved up and down by an elevator (not shown) installed in the second transfer chamber 121 and reciprocated in the left-right direction by a linear actuator (not shown). It is configured to be.

  As shown in FIG. 3, an orientation flat aligning device 106 is installed on the left side of the second transfer chamber 121. Further, as shown in FIG. 3, a clean unit (not shown) for supplying clean air is installed in the upper part of the second transfer chamber 121.

  As shown in FIG. 3, the housing 125 of the second transfer chamber 121 has a wafer loading / unloading port 134 for loading / unloading the wafer 200 into / from the second transfer chamber 121, and the wafer loading / unloading. A lid (not shown) for closing the carry-out port and a pod opener 108 are installed. The pod opener 108 includes a cap of the pod 100 placed on the IO stage 105 and a cap opening / closing mechanism (not shown) that opens and closes a lid that closes the wafer loading / unloading port 134, and is placed on the IO stage 105. The cap of the pod 100 and the lid that closes the wafer carry-in / out port 134 are opened and closed by the cap opening / closing mechanism, whereby the pod 100 can be taken in and out of the wafer. The pod 100 is supplied to and discharged from the IO stage 105 by an in-process transfer device (RGV) (not shown).

  As shown in FIG. 3, two side walls located on the back side among the six side walls of the housing 101 have a first processing furnace 202 for performing a desired process on the wafer, and a second side A processing furnace 137 is connected adjacently. Both the first processing furnace 202 and the second processing furnace 137 are each constituted by a cold wall type processing furnace. The remaining two side walls of the casing 101 that are opposite to each other are provided with a first cooling unit 138 as a third processing furnace and a second processing furnace as a fourth processing furnace. A cooling unit 139 is connected to each other, and both the first cooling unit 138 and the second cooling unit 139 are configured to cool the processed wafer 200.

  Hereinafter, a processing process using the substrate processing apparatus having the above-described configuration will be described.

  In a state where 25 unprocessed wafers 200 are accommodated in the pod 100, the unprocessed wafer 200 is transferred to the substrate processing apparatus that performs the processing process by the in-process transfer apparatus. As shown in FIG. 3, the pod 100 that has been transported is delivered from the in-process transport device and placed on the IO stage 105. The cap for opening / closing the cap of the pod 100 and the wafer loading / unloading port 134 is removed by the cap opening / closing mechanism, and the wafer loading / unloading port of the pod 100 is opened.

  When the pod 100 is opened by the pod opener 108, the second wafer transfer machine 124 installed in the second transfer chamber 121 picks up two wafers 200 from the pod 100 and loads them into the spare chamber 122. Two wafers 200 are transferred to the substrate table 140. During this transfer operation, the gate valve 244 on the first transfer chamber 103 side is closed, and the negative pressure in the first transfer chamber 103 is maintained. When the transfer of the wafer 200 to the substrate table 140 is completed, the gate valve 128 is closed, and the preliminary chamber 122 is exhausted to a negative pressure by an exhaust device (not shown).

  When the preliminary chamber 122 is depressurized to a preset pressure value, the gate valves 244 and 130 are opened, and the preliminary chamber 122, the first transfer chamber 103, and the first processing furnace 202 are communicated. Subsequently, the first wafer transfer machine 112 in the first transfer chamber 103 picks up two wafers 200 from the substrate table 140 and loads them into the first processing furnace 202. Then, a processing gas is supplied into the first processing furnace 202 and a desired process is performed on the wafer 200.

  When the processing is completed in the first processing furnace 202, the two processed wafers 200 are carried out to the first transfer chamber 103 by the first wafer transfer device 112 in the first transfer chamber 103.

  Then, the first wafer transfer machine 112 carries the wafer 200 unloaded from the first processing furnace 202 into the first cooling unit 138, and cools the processed wafer.

  When the two wafers 200 are transferred to the first cooling unit 138, the first wafer transfer device 112 transfers the two wafers 200 prepared in advance on the substrate mounting table 140 in the preliminary chamber 122 to the first processing furnace. The wafer is transferred to 202 by the above-described operation, a processing gas is supplied into the first processing furnace 202, and a desired processing is performed on the wafer 200.

  When a preset cooling time has elapsed in the first cooling unit 138, the cooled wafer 200 is unloaded from the first cooling unit 138 to the first transfer chamber 103 by the first wafer transfer device 112.

  After the two cooled wafers 200 are carried out from the first cooling unit 138 to the first transfer chamber 103, the gate valve 127 is opened. The first wafer transfer device 112 then transports the two wafers 200 unloaded from the first cooling unit 138 to the preliminary chamber 123 and transfers them to the substrate table 141, and then the preliminary chamber 123 has the gate valve 127. Closed by.

  When the preliminary chamber 123 is closed by the gate valve 127, the inside of the discharge preliminary chamber 123 is returned to the atmospheric pressure by the inert gas. When the inside of the preliminary chamber 123 is returned to substantially atmospheric pressure, the gate valve 129 is opened, and a lid for closing the wafer loading / unloading port 134 corresponding to the preliminary chamber 123 of the second transfer chamber 121 and the IO stage 105 are mounted. The cap of the placed empty pod 100 is opened by the pod opener 108. Subsequently, the second wafer transfer device 124 in the second transfer chamber 121 picks up the two wafers 200 from the substrate table 141 and carries them out to the second transfer chamber 121. The wafer is stored in the pod 100 through the wafer loading / unloading port 134. When the storage of the 25 processed wafers 200 into the pod 100 is completed, the pod opener 108 closes the lid that closes the cap of the pod 100 and the wafer loading / unloading port 134. The closed pod 100 is transferred from the top of the IO stage 105 to the next process by the in-process transfer apparatus.

  By repeating the above operation, the wafers are sequentially processed two by two. The above operation has been described by taking the case where the first processing furnace 202 and the first cooling unit 138 are used as an example, but also when the second processing furnace 137 and the second cooling unit 139 are used. Similar operations are performed.

  In the above-described substrate processing apparatus, the spare chamber 122 is used for carrying in and the spare chamber 123 is used for carrying out. However, the spare chamber 123 may be used for carrying in, and the spare chamber 122 may be used for carrying out. Moreover, the 1st processing furnace 202 and the 2nd processing furnace 137 may perform the same process, respectively, and may perform another process. When performing another process in the first process furnace 202 and the second process furnace 137, for example, after performing a process on the wafer 200 in the first process furnace 202, another process is performed in the second process furnace 137. Processing may be performed. In the case where another process is performed in the second processing furnace 137 after performing a process on the wafer 200 in the first processing furnace 202, the first cooling unit 138 (or the second cooling unit 139) is installed. You may make it go through.

  As shown in FIG. 4, the processing furnace 202 according to the present invention is configured as a single wafer CVD furnace (single wafer cold wall CVD furnace), and a wafer (semiconductor wafer) as a substrate to be processed. A chamber 223 in which a processing chamber 201 for processing 200 is formed is provided. The chamber 223 is formed in a cylindrical shape in which an upper cap 224, a cylindrical cup 225, and a lower cap 226 are combined so that upper and lower end surfaces are closed.

  A wafer loading / unloading port 250 that is opened and closed by a gate valve 244 is opened horizontally in the middle of the cylindrical wall of the cylindrical cup 225 of the chamber 223. The wafer loading / unloading port 250 is a wafer 200 that is a substrate to be processed. Is formed in the processing chamber 201 so that it can be loaded and unloaded by a wafer transfer device (not shown in FIG. 4). That is, the wafer 200 is transported through the wafer loading / unloading port 250 and loaded into and unloaded from the processing chamber 201 while being mechanically supported from below by the wafer transfer device.

  An exhaust port 235 connected to an exhaust device (not shown) such as a vacuum pump communicates with the processing chamber 201 at the upper part of the wall surface of the cylindrical cup 225 facing the wafer loading / unloading port 250. The inside of the processing chamber 201 is exhausted by an exhaust device.

  Further, an exhaust buffer space 249 communicating with the exhaust port 235 is formed in an annular shape in the upper part of the cylindrical cup 225, and acts so that the exhaust is uniformly performed on the entire surface of the wafer 200 together with the cover plate 248.

  The cover plate 248 extends on a part of the susceptors 217 so as to cover the edge portion of the wafer 200 and is used to control a CVD film formed on the edge portion of the wafer 200.

  A shower head 236 for supplying a processing gas is integrally incorporated in the upper cap 224 of the chamber 223. That is, a gas supply pipe 232 is inserted into the ceiling wall of the upper cap 224, and each gas supply pipe 232 has, for example, processing gases A and B (such as source gas and purge gas) (see examples below for details of A and B), A gas supply device including an on-off valve 243 and a flow rate control device (mass flow controller = MFC) 241 is connected to introduce gas C (not shown) as required. A disc-shaped shower plate (hereinafter referred to as a plate) 240 is horizontally fixed on the lower surface of the upper cap 224 at a distance from the gas supply pipe 232. The outlets (hereinafter referred to as “blow-out outlets”) 247 are provided so as to be uniformly arranged over the entire surface and to circulate through the upper and lower spaces.

  A buffer chamber 237 is formed by an inner space in which the inner surface of the upper cap 224 and the upper surface of the plate 240 are formed, and the buffer chamber 237 diffuses the processing gas 230 introduced into the gas supply pipe 232 evenly as a whole. It is made to blow out from each blower outlet 247 equally in the shape of a shower.

  An insertion hole 278 is formed in a circular shape at the center of the lower cap 226 of the chamber 223, and a support shaft 276 formed in a cylindrical shape is inserted into the processing chamber 201 from below on the center line of the insertion hole 278. .

  The support shaft 276 is raised and lowered by an elevating mechanism (elevating means) 268 using an air cylinder device or the like.

  A heating unit 251 is concentrically arranged at the upper end of the support shaft 276 and is fixed horizontally. The heating unit 251 is moved up and down by the support shaft 276. That is, the heating unit 251 includes a support plate 258 formed in a disc shape, and the support plate 258 is fixed concentrically to the upper end opening of the support shaft 276. On the upper surface of the support plate 258, a plurality of electrode terminals 253 that also serve as columns are vertically erected. Between the upper ends of these electrode terminals 253, a heater (heating means) 207 is bridged and fixed at a position facing the main surface 200 a of the wafer 200 via a susceptor 217. The heater 207 has a plurality of heater patterns that are formed in a disc shape and are zone-divided into a plurality of zones. The plurality of heater patterns are concentrically divided into a center, a middle, and an outer. The electrical wiring 257 for the electrode terminal 253 is inserted through the hollow portion of the support shaft 276.

  In addition, a reflector 252 is fixed to the support plate 258 below the heater 207, and heat generated from the heater 207 is reflected toward the susceptor 217 so that efficient heating is performed.

  Further, a radiation thermometer 263 that is a temperature detecting means is provided in the heater 207 so that its detecting portion faces the susceptor 217. The radiation thermometer 263 is used to acquire the temperature of the susceptor 217 (the temperature of the susceptor 217 can be calculated from the temperature of the wafer 200 based on the relationship between the temperature of the wafer 200 and the susceptor 217 acquired in advance, or vice versa. The temperature of the wafer 200 can be calculated from the temperature of the susceptor 217), and the heating power of the heater 217 is controlled by adjusting the heater power based on this calculation result.

  On the outside of the support shaft 276 of the insertion hole 278 of the lower cap 226, a rotating shaft 277 formed in a cylindrical shape having a larger diameter than the support shaft 276 is disposed concentrically and is inserted into the processing chamber 201 from below. The rotary shaft 277 is lifted and lowered together with the support shaft 276 by a lifting mechanism 268 using an air cylinder device or the like. A rotating drum 227 is concentrically arranged at the upper end of the rotating shaft 277 and fixed horizontally. The rotating drum 227 is rotated by the rotating shaft 277. That is, the rotating drum 227 includes a rotating plate 229 formed in a donut-shaped flat plate and a rotating cylinder 228 formed in a cylindrical shape, and an inner peripheral edge of the rotating plate 229 is an upper end of a cylindrical rotating shaft 277. A rotating cylinder 228 is concentrically fixed to the outer peripheral edge of the upper surface of the rotating plate 229 and is fixed to the opening. A susceptor 217 formed in a disk shape using silicon carbide, aluminum nitride or the like is placed on the upper end of the rotating cylinder 228 of the rotating drum 227 so as to close the upper end opening of the rotating cylinder 228.

  As shown in FIG. 4, a wafer elevating device 275 is installed on the rotary drum 227. The wafer elevating device 275 is composed of two elevating rings formed in a circular ring shape with projecting pins (substrate projecting means) 266 and 274 projecting from each other. The rotation side ring is disposed on the rotating plate 229 of the rotating drum 227 concentrically with the support shaft 276. A plurality of (three in the present embodiment) protruding pins (hereinafter referred to as “rotating side pins”) 274 are arranged on the lower surface of the rotating side ring at equal intervals in the circumferential direction and vertically downward. Each rotation-side pin 274 is slidably fitted in each guide hole 255 that is arranged on the rotation plate 229 on a line concentric with the rotation cylinder 228 and opened in the vertical direction. The lengths of the rotation-side pins 274 are set to be equal to each other so that the rotation-side ring can be pushed up horizontally, and are set to correspond to the push-up amount of the wafer from the susceptor. The lower end of each rotation side pin 274 is opposed to the bottom surface of the processing chamber 201, that is, the upper surface of the lower cap 226 so as to be separable.

  On the support plate 258 of the heating unit 251, another lifting ring (hereinafter referred to as a heater side ring) formed in a circular ring shape is disposed concentrically with the support shaft 276. On the lower surface of the heater side ring, a plurality of (three in the present embodiment) protruding pins (hereinafter referred to as heater side pins) 266 are arranged at equal intervals in the circumferential direction and vertically downward. Each heater-side pin 266 is slidably fitted in each guide hole 254 that is arranged on the support plate 258 on a line concentric with the support shaft 276 and opened in the vertical direction. The lengths of these heater-side pins 266 are set to be equal to each other so that the heater-side ring can be pushed up horizontally, and their lower ends are opposed to the upper surface of the rotation-side ring with an appropriate air gap. That is, these heater side pins 266 do not interfere with the rotation side ring when the rotation drum 227 rotates.

  In addition, a plurality of (three in the present embodiment) protruding pins (hereinafter referred to as protruding portions) 266 are arranged on the upper surface of the heater side ring at equal intervals in the circumferential direction. The upper end of the protruding portion 266 is opposed to the heater 207 and the insertion hole 256 of the susceptor 217. The lengths of these protrusions 266 are set to be equal to each other so that the wafer 200 held by the susceptor 217 is horizontally floated from the susceptor 217 through the heater 207 and the insertion hole 256 of the susceptor 217 from below. Further, the lengths of these protrusions 266 are set so that the upper ends of the protrusions 266 do not protrude from the upper surface of the heater 207 when the heater side ring is seated on the support plate 258. That is, these protrusions 266 do not interfere with the susceptor 217 during rotation of the rotary drum 227 and do not hinder the heating of the heater 207.

  As shown in FIG. 4, the chamber 223 is horizontally supported by a plurality of columns 280. Each elevating block 281 is fitted to these columns 280 so as to be movable up and down, and an elevating platform that is raised and lowered by an elevating drive device (not shown) using an air cylinder device or the like is interposed between the elevating blocks 281. 282 is installed. A susceptor rotating device is installed on the lifting platform 282, and a bellows 279 is provided between the susceptor rotating device and the chamber 223 so as to hermetically seal the outside of the rotating shaft 277.

  A brushless DC motor is used for the susceptor rotating mechanism (rotating means) 267 installed on the lifting platform 282, and an output shaft (motor shaft) is formed as a hollow shaft and configured as a rotating shaft 277. The susceptor rotating mechanism 267 includes a housing 283, and the housing 283 is installed on the elevator base 282 in the vertical upward direction. A stator (stator) 284 composed of an electromagnet (coil) is fixed to the inner peripheral surface of the housing 283. That is, the stator 284 is configured by winding a coil wire (enamel-coated copper wire) 286 around an iron core (core) 285. A lead wire (not shown) is electrically connected to the coil wire 286 through an insertion hole (not shown) formed in the side wall of the housing 283, and the stator 284 receives electric power from a brushless DC motor driver (not shown). Is supplied to the coil wire 286 through a lead wire to form a rotating magnetic field.

  A magnetic sensor 295 for detecting each tooth which is a detected portion of the detected ring 296 is installed at a position of the housing 283 facing the detected ring 296. The detection result of the magnetic sensor 295 is transmitted to the drive control unit of the brushless DC motor, that is, the susceptor rotation mechanism 267, and used for recognizing the position of the susceptor 217 and used to control the rotation amount of the susceptor 217. The processing furnace 202 includes a main control unit 300 including a gas control unit 301, a drive control unit 302, a heating control unit 303, a temperature detection unit 304, and the like. The gas control unit 301 is connected to the MFC 241 and the open / close valve 243 and controls the gas flow rate and supply. The drive control unit 302 is connected to the susceptor rotating mechanism 267 and the lifting block 281 and controls the driving thereof.

  The heating control unit 303 is connected to the heater 207 via the wiring 257 and controls the heating state of the heater 207. The temperature detection unit 304 is connected to the radiation thermometer 263 via the lead wire 264, detects the temperature of the susceptor 217, and is used for heating control of the heater 207 in cooperation with the heating control unit 303.

  Next, by describing the operation of the processing furnace according to the above configuration, a film forming process in the method for manufacturing a semiconductor device according to an embodiment of the present invention will be described.

  When the wafer 200 is carried in and out, the rotary drum 227 and the heating unit 251 are lowered to the lower limit position by the rotary shaft 277 and the support shaft 276. Then, since the lower end of the rotation-side pin 274 of the wafer lifting device 275 abuts the bottom surface of the processing chamber 201, that is, the upper surface of the lower cap 226, the rotation-side ring rises relative to the rotation drum 227 and the heating unit 251. . The raised rotation side ring lifts the heater side ring by pushing up the heater side pin 266. When the heater side ring is lifted, the three projecting upper portions 266 standing on the heater side ring pass through the heater 207 and the insertion hole 256 of the susceptor 217 to support the wafer 200 held on the upper surface of the susceptor 217 from below. And lift from the susceptor 217.

  When the wafer lifting device 275 is in a state where the wafer 200 is lifted from the upper surface of the susceptor 217, an insertion space is formed between the lower space of the wafer 200, that is, the lower surface of the wafer 200 and the upper surface of the susceptor 217. A tweezer which is a substrate holding plate provided in a wafer transfer machine (not shown in FIG. 4) is inserted into the insertion space of the wafer 200 from the wafer loading / unloading port 250. The tweezer inserted below the wafer 200 moves up and receives the wafer 200. Upon receiving the wafer 200, the tweezer retreats from the wafer loading / unloading port 250 and unloads the wafer 200 from the processing chamber 201. Then, the wafer transfer machine that unloads the wafer 200 by the tweezer transfers the wafer 200 to a predetermined storage location such as an empty wafer cassette outside the processing chamber 201.

  Next, the wafer transfer machine receives a wafer 200 to be subjected to a film formation process next time from a predetermined storage location such as an actual wafer cassette by a tweezer, and carries it into the processing chamber 201 from the wafer loading / unloading port 250. The tweezers transport the wafer 200 above the susceptor 217 to a position where the center of the wafer 200 coincides with the center of the susceptor 217. When the wafer 200 is transported to a predetermined position, the tweezers are slightly lowered to transfer the wafer 200 to the susceptor 217. The tweezer that has transferred the wafer 200 to the wafer lift 275 moves out of the processing chamber 201 from the wafer loading / unloading port 250. When the tweezer leaves the processing chamber 201, the wafer loading / unloading port 250 is closed by a gate valve (gate valve) 244.

  When the gate valve 244 is closed, the rotary drum 227 and the heating unit 251 are lifted by the lift table 282 through the rotary shaft 277 and the support shaft 276 with respect to the processing chamber 201. As the rotary drum 227 and the heating unit 251 are raised, the thrust pins 266 and 274 are lowered relative to the rotary drum 227 and the heating unit 251, and the wafer 200 is placed on the susceptor 217 as shown in FIG. It will be in the state completely transferred to. The rotation shaft 277 and the support shaft 276 are stopped at a position where the upper end of the protrusion 266 is at a height close to the lower surface of the heater 207.

  On the other hand, the processing chamber 201 is exhausted by an exhaust device (not shown) connected to the exhaust port 235. At this time, the vacuum atmosphere in the processing chamber 201 and the external atmospheric pressure atmosphere are isolated by the bellows 279.

  Subsequently, the rotating drum 227 is rotated by the susceptor rotating mechanism 267 via the rotating shaft 277. That is, when the susceptor rotating mechanism 267 is operated, the rotating magnetic field of the stator 284 cuts the magnetic field of the plurality of magnetic poles of the rotor 289, so that the rotor 289 rotates, so that the rotation fixed to the rotor 289 The rotating drum 227 is rotated by the shaft 277. At this time, the rotational position of the rotor 289 is detected momentarily by the magnetic rotary encoder 294 installed in the susceptor rotation mechanism 267 and transmitted to the drive control unit 302, and the rotation speed and the like are controlled based on this signal. .

  During the rotation of the rotating drum 227, the rotation side pin 274 is separated from the bottom surface of the processing chamber 201, and the heater side pin 266 is separated from the rotation side ring. In addition, the heating unit 251 can maintain a stopped state. That is, in the wafer elevating device 275, the rotation side ring and the rotation side pin 274 rotate together with the rotation drum 227, and the heater side ring and the heater side pin 266 are stopped together with the heating unit 251.

  When the temperature of the wafer 200 rises to the processing temperature and the exhaust amount of the exhaust port 235 and the rotational operation of the rotary drum 227 are stabilized, the processing gas 230 is supplied to the supply pipe 232 as shown by solid arrows in FIG. To be introduced. The processing gas 230 introduced into the gas supply pipe 232 flows into the buffer chamber 237 functioning as a gas dispersion space and diffuses radially outward in the radial direction. It becomes a substantially uniform flow and blows out toward the wafer 200 in a shower shape.

  The processing gas 230 blown out in the form of a shower from the group of the outlets 247 passes through the space above the cover plate 248 and is sucked into the exhaust port 235 via the exhaust buffer space 249 and exhausted.

  At this time, since the wafer 200 on the susceptor 217 supported by the rotating drum 227 is rotating, the processing gas 230 blown out in a shower form from the group of the outlets 247 comes into contact with the entire surface of the wafer 200 evenly. Since the processing gas 230 is in uniform contact with the entire surface of the wafer 200, the film thickness distribution and film quality distribution of the CVD film formed on the wafer 200 by the processing gas 230 are uniform over the entire surface of the wafer 200.

  Since the heating unit 251 is not rotated by being supported by the support shaft 276, the temperature distribution of the wafer 200 heated by the heating unit 251 while being rotated by the rotating drum 227 is uniformly controlled over the entire surface. The Thus, by uniformly controlling the temperature distribution of the wafer 200 over the entire surface, the film thickness distribution and film quality distribution of the CVD film formed on the wafer 200 by the thermochemical reaction are controlled uniformly over the entire surface of the wafer 200.

  When a predetermined processing time selected in advance elapses, the operation of the susceptor rotation mechanism 267 is stopped. At this time, since the rotational position of the susceptor 217, that is, the rotor 289 is monitored every moment by the magnetic rotary encoder 294 installed in the susceptor rotating mechanism 267, the susceptor 217 is accurately stopped at the preset rotational position. The That is, the protrusion 266 and the heater 207 and the insertion hole 256 of the susceptor 217 are matched accurately and with good reproducibility.

  When the operation of the susceptor rotating mechanism 267 is stopped, as described above, the rotating drum 227 and the heating unit 251 are lowered to the loading / unloading position by the lifting platform 282 via the rotating shaft 277 and the support shaft 276. . As described above, the wafer 200 is lifted from above the susceptor 217 by the action of the wafer lifting device 275 during the lowering. At this time, the protruding portion 266 and the insertion hole 256 of the heater 207 and the susceptor 217 are matched accurately and with good reproducibility.

  Thereafter, by repeating the above-described operation, a CVD film is formed on the next wafer 200.

  By the way, in order to reduce the processing defect of the wafer due to the elastic deformation (wafer warpage) of the wafer 200, it is necessary to prevent the occurrence of the warpage of the wafer. As described above, the warpage of the wafer depends on the pattern on the wafer or the thermal history of the wafer, and cannot be sufficiently prevented. For this reason, in the present embodiment, the occurrence of warpage is not prevented in advance, but when the wafer warps, the generated warpage is detected quickly. Therefore, the existing substrate heating control system is improved.

  The configuration of the substrate heating control system of the embodiment is basically the same as the conventional example. The difference is that a monitor function for monitoring the heater supply power is added to the controller.

  A processing furnace provided with a substrate heating control system according to an embodiment to which the above monitoring function is added will be described with reference to FIG.

As shown in FIG. 1, the substrate processing apparatus includes a chamber 223 capable of supplying and exhausting a gas as a wafer container, a susceptor 217 as a substrate holding means for holding a wafer 200 accommodated in the chamber 223, and a heating means. As a heater 207. Gas supply is performed from a gas supply pipe 232 provided in the chamber 223, and the atmosphere in the chamber 223 is exhausted from the exhaust port 235.
Further, a radiation thermometer 263 as temperature detecting means for detecting the temperature of the susceptor 217, and an A / D converter 51 as a temperature detecting unit 304 (see FIG. 4) for converting an analog signal of the radiation thermometer 263 into a digital signal. Power supply means 53 for supplying power from the AC power supply 52 to the heater 207 in accordance with the phase control amount, control means 54 for controlling the phase control amount of the power supply means 53, temperature control of the susceptor 217, and heater 207 And a controller 55 for monitoring the power supplied to. The power supply means 53 and the control means 54 described above constitute a power control means 57. The power supply means 53, the control means 54, and the controller 55 constitute a heating control unit 303 (see FIG. 4).

  The power supply means 53 described above performs phase control based on the phase control signal by the thyristor, and supplies the power controlled by the phase control to the heater 207. The heater power can be controlled over 0% to 100% (full power). Further, the actual phase control amount is detected from the power supply means 53 and is input to the controller 55 as monitor power. Note that the phase control amount may be input to the controller 55 as monitor power from the control means 54 described later.

  The control means 54 calculates and obtains a phase control amount based on the power setting signal input from the controller 55 and outputs it to the power supply means 53 as a phase control signal. Note that the phase control amount may be obtained by a lookup table instead of the calculation.

  The controller 55 is set with a set temperature that is a target temperature of the susceptor 217. The controller 55 compares the set temperature with the detected temperature of the susceptor 217 taken out from the A / D converter 51, and controls the control means based on the difference between the detected temperature and the set temperature so that the detected temperature becomes the set temperature. The power setting signal is output to 54. Further, in order to detect wafer warpage, the controller 55 includes an allowable deviation value of power supplied to the heater 207, that is, an allowable deviation value between the monitor power and the power upper limit set value, and a monitor power and a power lower limit set value. The allowable deviation values are set respectively. The controller 55 compares the power upper limit set value and the power lower limit set value with the monitor power acquired from the power supply means 53, and when the monitor power exceeds the upper limit set value or falls below the lower limit set value (lower limit setting). It is configured to output an abnormal signal when the value is exceeded. The abnormal signal is applied to an alarm notification device as an alarm output means including a speaker, a buzzer, or an alarm display (not shown).

The operation of the substrate heating control system configured as described above is as follows.
The controller 55 calculates the temperature of the susceptor 207 from which the wafer target temperature can be obtained in the preheating step and the main heating step described later, and sets the calculated set temperature of the susceptor 207 in advance. The wafer target temperature is determined by the thin film formation of the wafer and the contents of the heat treatment. Further, an upper limit set value and a lower limit set value of the monitor power are set in the controller 55 in advance so that the monitor power can be compared and determined during the preheating step. The upper limit set value or the lower limit set value is a value that does not exceed the monitor power value during normal processing in which wafer warpage does not occur during wafer heating.

  The temperature of the susceptor 217 in the processing chamber is detected by the radiation thermometer 56. Detection is by sampling. The detection cycle is preferably as short as possible within the range allowed by the control delay time from the viewpoint of temperature controllability. The controller 55 calculates the supply power necessary for setting the susceptor temperature to the set temperature from the difference between the susceptor set temperature and the susceptor detection temperature, and outputs this to the control means 54 as a power set signal. Based on the power setting signal from the controller 55, the control unit 54 calculates a phase control amount for setting the susceptor 217 to the set temperature, and outputs this to the power supply unit 53 as a phase control signal. The power supply unit 53 supplies the power controlled by the phase control amount to the heater 207. When electric power is supplied to the heater 207, the wafer 200 is heated to reach the target temperature via the susceptor 217. As described above, since the substrate heating control system feedback-controls the susceptor temperature according to the detected temperature, the susceptor set temperature is maintained after the susceptor 217 is heated to the set temperature. In general, the feedback control uses a PID arithmetic expression. When the susceptor set temperature is maintained and the inside of the container 223 reaches a predetermined pressure, wafer processing is performed by exhausting while introducing the reaction gas into the container 223.

  During heating of the heater, the amount of power supplied to the heater 207 is detected by the power supply means 53 and is constantly monitored by the controller 55. When the monitor power exceeds the upper limit set value or the lower limit set value set by the controller 55, the controller 55 considers that the wafer 200 has warped and outputs an abnormal signal. The heater power monitor is also detected by sampling in the same manner as the susceptor temperature detection.

Next, the operation of the substrate heating control system will be described more specifically with reference to FIG. FIG. 2 is a graph showing changes in heater power, susceptor temperature, and wafer temperature (parameters) during a wafer processing cycle.
The wafer processing cycle indicates the cycle up to the first, second, and third sheets. In the illustrated example, the first and second wafers are processed normally without deformation of the wafer. Wafer deformation occurred in the third sheet, and abnormal processing was performed.
The heater power is monitor power detected from the power supply means 53. The susceptor temperature is the temperature at which the two radiation thermometers 263 described with reference to FIG. 4 detect the central portion or the end portion of the susceptor 217 or the average value of the two temperatures. Even if the temperature of any part of the susceptor 217 is detected, the susceptor temperature behaves as shown. The wafer temperature is not detected in the embodiment, but FIG. 2 shows the wafer temperature converted from the susceptor temperature for reference. The wafer temperature is lower than the susceptor temperature because the wafer 200 is indirectly heated via the susceptor 217. Further, the wafer temperature characteristic appears in a form similar to the susceptor temperature characteristic.
The heater power, the susceptor temperature, and the wafer temperature have a certain correlation as long as normal substrate processing is performed even in a thermal non-equilibrium state. As shown in FIG. Normal substrate processing such as wafer processing also has reproducibility.

There are four steps constituting one cycle focusing on the heater power: an overheating step for rapid heating, a preheating step, a main heating step for processing the wafer, and a temperature lowering step for cooling the processed wafer. It consists of steps.
In the processing of the first and second wafers, the wafer 200 is not warped when the wafer is heated, and is normally processed as follows. In the overheating step, the full power (100%) power larger than the setting power in the preliminary heating step and the main heating step is used as the power supply means 53 with the phase control amount determined by the power setting signal from the controller 55. The susceptor 217 is rapidly heated by rapidly supplying to the heater 207. After applying the full power power to the heater 207 for a predetermined time, the power supply to the heater 207 is temporarily interrupted, the power value is rapidly decreased, and when the power value is slightly below the set power value, the power supply is resumed, and then Supply set power. While the controller 55 performs feedback control based on the detected susceptor temperature, the preheating step and the main heating step are executed. Wafer processing is performed during the main heating, and after the wafer processing is completed, the power supply to the heater 207 is cut off and a temperature lowering step is entered to lower the susceptor temperature and cool the wafer 200.

In the third wafer processing, since the wafer is warped during the wafer heating process, the abnormal processing is performed as follows.
If the spatial distance from the surface of the susceptor 217 becomes non-uniform due to wafer warpage, the total amount of heat transferred between the susceptor 217 and the wafer 200 varies greatly with respect to normal processing in which no wafer warpage occurs. This is because the heat transfer medium is changed from solid to gas, and the heat transfer by the gas greatly depends on the spatial distance, and the total heat transfer amount is generally reduced. The decrease in the total heat transfer greatly affects the heater power. For example, when the temperature of the wafer 200 is obtained empirically based on the detected temperature of the susceptor 217 for indirectly heating the wafer 200, the heater power is increased as in the third wafer processing shown in FIG. Is greatly reduced. When the heater power falls below the preset power lower limit value in this way, an abnormal signal is output, an alarm is issued if necessary, the wafer processing is interrupted, and the wafer collection operation is started.

  This will be described more specifically. In the third wafer processing, the wafer 200 is warped during the overheating step. For example, a part of the wafer 200 is bent concavely on the opposite side of the susceptor, not on the susceptor 217 side. Suppose that the part is separated from the susceptor surface. The portion of the susceptor 217 facing the part of the wafer 200 that has been separated has a lower thermal conductivity from the portion of the susceptor 217 to the wafer 200 than when the wafer 200 is not warped. Therefore, the portion of the susceptor 217 can be quickly raised to the susceptor set temperature with less heater power during the overheating step, and less heater power during the preheating step and the main heating step. Thus, this portion of the susceptor 217 can be maintained at the set temperature. As a result, as shown in the figure, the monitor power detected by the controller 55 falls below the power lower limit set value.

  That is, in the embodiment, the power is monitored to detect the warpage of the wafer 200 on the premise of the feedback control of the wafer temperature. However, even if the susceptor temperature is controlled to the set temperature by feedback control, the wafer temperature may not reach the set temperature due to the warpage of the wafer 200. In that case, the power supply amount deviates from the range of the allowable deviation value as described above.

  Then, the controller 55 regards the wafer as being warped, outputs an abnormal signal, and issues an alarm as necessary. The substrate processing is interrupted by this alarm. The interruption of the process can be automatically performed in conjunction with the abnormal signal, and the range can be set in the controller 55 as a parameter. By issuing an alarm, the operator handles the interrupted processing wafer as a defective product. Therefore, it is possible to effectively prevent non-uniformity such as the film thickness of the thin film formed on the wafer and defect processing, unlike the case of overlooking the wafer defect and continuing the processing as it is. Yield is improved. Further, by preventing film formation on an unexpected part in the processing chamber, foreign matter generation can be prevented, apparatus troubles can be prevented, and the MTBF can be improved.

Note that up to one example, the processing conditions processed in the processing furnace 202 according to the present embodiment are as follows.
Film type: phosphorus-doped polysilicon (P-Doped Poly-Si)
Heater power:
Center approximately 30% (rated 2Kw), middle approximately 30% (rated 3Kw), outer approximately 50% (rated 4Kw)
Wafer diameter: φ300 mm, wafer temperature: 700 ° C., pressure: 24000 Pa
Gas A: Nitrogen 20 slm, Gas B: Monosilane 0.3 slm, Gas C: Phosphine 0.3 slm
Power cap setting value:
Center 50-100%, Middle 50-100%, Outer 70-100%
Lower power setting value:
Center 25-0%, Middle 25-0%, Outer 40-0%

  Note that the power upper limit set value and lower limit set value cannot be determined unconditionally. The degree of deformation greatly depends on the presence / absence of a film on the wafer (film type, thickness, pattern, laminated state). Therefore, when the wafer is deformed, the fluctuating power value also changes. Actually, after intentionally generating warpage (abnormal processing), power comparison with normal processing is performed for each product type and determined.

In the above-described embodiment, the abnormal phenomenon in the case where the power lower limit set value is exceeded has been described. However, the present invention can be applied to a case where the power upper limit is exceeded. For example, the following cases can be considered as cases where the power upper limit set value is exceeded due to non-uniform wafer temperature.
When the warpage of the wafer occurs, the thermal conductivity from the susceptor 217 to the wafer 200 decreases, so that the power upper limit set value is not normally exceeded. However, the substrate processing apparatus according to the embodiment includes a susceptor rotating mechanism (rotating unit) 267. When a wafer warp occurs, the radiation thermometer is rotated in the order of (a position that is warped and floating) → (a position that is warped but is in contact) → (a position that is warped and floating). When the temperature of the susceptor 217 is detected by H.263, although it is extreme, the power supply amount to be PID controlled becomes 0% → 100% → 0%... And may exceed the power upper limit set value.

In the above-described embodiment, the case where the temperature of the substrate holding means (susceptor) is detected to control the temperature of the wafer has been described. However, the temperature of the substrate may be directly detected.
Further, in the embodiment, the upper limit set value and the lower limit set value of the power to be monitored are set at the preheating step, and the heating abnormality is detected based on the set value. However, the present invention is not limited to this. . In each of the overheating step, the preheating step, the main heating step for processing the wafer, and the temperature decreasing step for cooling the processed wafer, a different power value is set for each to detect an abnormality. Is possible. In this case, considering the reduction of film stress and unnecessary thermal history due to wafer deformation, it is desirable to detect immediately after the wafer deformation occurs and perform the wafer recovery operation. However, wafer deformation does not always occur at a specific step, and the power value also changes continuously. Therefore, it is considered impossible to operate the detection function effectively at the same value for all steps. It is done. Therefore, by providing a different allowable deviation value at each step, it becomes possible to detect immediately after the wafer deformation occurs.
For example, as shown in FIG. 2, an upper limit set value and a lower limit set value of power to be monitored during the overheating step may be set, and a heating abnormality may be detected based on this set value.

  In the embodiment, since power is controlled by phase control using a thyristor, the amount of phase control is used for monitoring the heater power, but the heater power is measured using a voltage detector and a current detector. May be directly monitored.

It is the schematic of the processing furnace provided with the substrate heating control system which comprises the substrate processing apparatus by embodiment. It is explanatory drawing which shows each parameter transition at the time of the wafer normal process by embodiment, and a wafer abnormal process. 1 is a schematic diagram of a substrate processing apparatus according to an embodiment. It is a schematic sectional drawing which shows the outline of the processing furnace which comprises the substrate processing apparatus by embodiment. It is a schematic block diagram of the system of the substrate heating control by a prior art example.

Explanation of symbols

52 AC power supply 53 Power supply means 54 Control means 55 Controller 56 Radiation thermometer (temperature detection means)
57 Power control means 200 Wafer (substrate)
223 chamber
217 susceptor (substrate holding means)
207 Heater (heating means)

Claims (1)

A container for containing a substrate;
Substrate holding means for holding a substrate housed in the container;
Heating means for heating the substrate held by the substrate holding means;
Power control means for controlling power supplied from a power source to the heating means;
Temperature detecting means for detecting the temperature of the substrate or the substrate holding means;
A controller that controls the power control means so that the detected temperature becomes a set temperature by comparing the detected temperature detected by the temperature detecting means with a preset temperature of the substrate or the substrate holding means;
The controller is preset with an allowable upper limit value or a lower limit value of power supplied from the power control means to the heating means when the substrate held by the substrate holding means does not undergo elastic deformation during heating. The power supplied from the power supply means to the heating means is monitored, the monitor power is compared with the upper limit value or the lower limit value, and when the monitor power exceeds the upper limit value or the lower limit value, an abnormal signal Is output.

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