WO2021049283A1 - Procédé de traitement thermique et appareil de traitement thermique - Google Patents

Procédé de traitement thermique et appareil de traitement thermique Download PDF

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Publication number
WO2021049283A1
WO2021049283A1 PCT/JP2020/031834 JP2020031834W WO2021049283A1 WO 2021049283 A1 WO2021049283 A1 WO 2021049283A1 JP 2020031834 W JP2020031834 W JP 2020031834W WO 2021049283 A1 WO2021049283 A1 WO 2021049283A1
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WIPO (PCT)
Prior art keywords
heat treatment
chamber
gas
semiconductor wafer
flash
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PCT/JP2020/031834
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English (en)
Japanese (ja)
Inventor
晃頌 上田
浩志 三宅
行雄 小野
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株式会社Ｓｃｒｅｅｎホールディングス
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Publication of WO2021049283A1 publication Critical patent/WO2021049283A1/fr

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/26—Bombardment with radiation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/26—Bombardment with radiation
    • H01L21/263—Bombardment with radiation with high-energy radiation
    • H01L21/265—Bombardment with radiation with high-energy radiation producing ion implantation

Definitions

  • the present invention relates to a heat treatment method and a heat treatment apparatus for heating a thin plate-shaped precision electronic substrate (hereinafter, simply referred to as "substrate”) such as a semiconductor wafer by irradiating the substrate with flash light.
  • substrate thin plate-shaped precision electronic substrate
  • Flash lamp annealing In the semiconductor device manufacturing process, flash lamp annealing (FLA), which heats a semiconductor wafer in an extremely short time, is attracting attention.
  • FLA flash lamp annealing
  • Flash lamp annealing uses a xenon flash lamp (hereinafter, simply referred to as "flash lamp” to mean a xenon flash lamp) to irradiate the surface of the semiconductor wafer with flash light, so that only the surface of the semiconductor wafer is extremely exposed.
  • flash lamp xenon flash lamp
  • the radiation spectral distribution of the xenon flash lamp is from the ultraviolet region to the near infrared region, the wavelength is shorter than that of the conventional halogen lamp, and it almost coincides with the basic absorption band of the silicon semiconductor wafer. Therefore, when the semiconductor wafer is irradiated with the flash light from the xenon flash lamp, the transmitted light is small and the temperature of the semiconductor wafer can be rapidly raised. It has also been found that if the flash light is irradiated for an extremely short time of several milliseconds or less, the temperature can be selectively raised only in the vicinity of the surface of the semiconductor wafer.
  • Such flash lamp annealing is used for processing that requires heating for an extremely short time, for example, activation of impurities injected into a semiconductor wafer.
  • activation of impurities injected into a semiconductor wafer By irradiating the surface of a semiconductor wafer into which impurities have been implanted by the ion implantation method with flash light from a flash lamp, the surface of the semiconductor wafer can be raised to the activation temperature for a very short time, and the impurities are deeply diffused. Only impurity activation can be performed without causing it.
  • Patent Document 1 states that after preheating a semiconductor wafer by irradiating light from a halogen lamp, the surface of the semiconductor wafer is exposed to flash light from a flash lamp for 1 second or less. A device for heating for a short time is disclosed.
  • the flash lamp annealing apparatus disclosed in Patent Document 1 after the flash heating is completed, the temperature of the semiconductor wafer is lowered to a predetermined temperature or less by natural cooling, and then the semiconductor wafer is carried out from the chamber.
  • the present invention has been made in view of the above problems, and an object of the present invention is to provide a heat treatment method and a heat treatment apparatus capable of efficiently and quickly cooling the inside of a chamber.
  • the first aspect of the present invention is a heat treatment method for heating a substrate by irradiating the substrate with flash light, in which the substrate is accommodated in a chamber and the substrate is accommodated in the chamber.
  • the cooling gas is hydrogen or helium.
  • the supply of the cooling gas is started after the time when the substrate is irradiated with the flash light.
  • the supply of the cooling gas is started when the continuous lighting lamp is turned off.
  • the supply of the cooling gas is stopped when the temperature inside the chamber is lowered to a predetermined temperature.
  • the chamber containing the substrate and the substrate housed in the chamber are irradiated with light to irradiate the substrate.
  • the cooling gas is hydrogen or helium.
  • the gas supply unit starts supplying the cooling gas after the time when the substrate is irradiated with the flash light.
  • the gas supply unit starts supplying the cooling gas when the continuous lighting lamp is turned off.
  • the gas supply unit stops the supply of the cooling gas when the temperature inside the chamber is lowered to a predetermined temperature. ..
  • the inside of the chamber is efficiently and quickly cooled by the cooling gas having a high cooling ability. can do.
  • the supply of the cooling gas is stopped when the temperature inside the chamber is lowered to a predetermined temperature, so that the components in the chamber are prevented from being excessively cooled.
  • the temperature history of the substrate can be made uniform.
  • the heat treatment apparatus in order to supply the cooling gas having a thermal conductivity higher than that of nitrogen into the chamber, the inside of the chamber is efficiently and quickly cooled by the cooling gas having a high cooling ability. can do.
  • the supply of the cooling gas is stopped when the temperature inside the chamber is lowered to a predetermined temperature, so that the components in the chamber are prevented from being excessively cooled.
  • the temperature history of the substrate can be made uniform.
  • FIG. 1 is a vertical cross-sectional view showing the configuration of the heat treatment apparatus 1 according to the present invention.
  • the heat treatment apparatus 1 of FIG. 1 is a flash lamp annealing apparatus that heats a disk-shaped semiconductor wafer W as a substrate by irradiating the semiconductor wafer W with flash light.
  • the size of the semiconductor wafer W to be processed is not particularly limited, but is, for example, ⁇ 300 mm or ⁇ 450 mm ( ⁇ 300 mm in this embodiment).
  • Impurities are injected into the semiconductor wafer W before it is carried into the heat treatment apparatus 1, and the activation treatment of the impurities injected by the heat treatment by the heat treatment apparatus 1 is executed.
  • the dimensions and numbers of each part are exaggerated or simplified as necessary for easy understanding.
  • the heat treatment apparatus 1 includes a chamber 6 for accommodating a semiconductor wafer W, a flash heating unit 5 containing a plurality of flash lamps FL, and a halogen heating unit 4 containing a plurality of halogen lamps HL.
  • a flash heating unit 5 is provided on the upper side of the chamber 6, and a halogen heating unit 4 is provided on the lower side.
  • the heat treatment apparatus 1 includes a holding portion 7 that holds the semiconductor wafer W in a horizontal position inside the chamber 6, a transfer mechanism 10 that transfers the semiconductor wafer W between the holding portion 7 and the outside of the apparatus. To be equipped.
  • the heat treatment apparatus 1 includes a halogen heating unit 4, a flash heating unit 5, and a control unit 3 that controls each operation mechanism provided in the chamber 6 to execute heat treatment of the semiconductor wafer W.
  • the chamber 6 is configured by mounting quartz chamber windows above and below the tubular chamber side portion 61.
  • the chamber side portion 61 has a substantially cylindrical shape with upper and lower openings, and the upper chamber window 63 is attached to the upper opening and closed, and the lower chamber window 64 is attached to the lower opening and closed.
  • the upper chamber window 63 constituting the ceiling portion of the chamber 6 is a disk-shaped member formed of quartz, and functions as a quartz window that transmits the flash light emitted from the flash heating portion 5 into the chamber 6.
  • the lower chamber window 64 constituting the floor portion of the chamber 6 is also a disk-shaped member formed of quartz, and functions as a quartz window that transmits light from the halogen heating portion 4 into the chamber 6.
  • a gas ring 90 is attached to the upper part of the inner wall surface of the chamber side portion 61, and a reflection ring 69 is attached to the lower part. Both the gas ring 90 and the reflection ring 69 are formed in an annular shape.
  • the inner space of the chamber 6, that is, the space surrounded by the upper chamber window 63, the lower chamber window 64, the chamber side 61, the reflection ring 69, and the gas ring 90 is defined as the heat treatment space 65.
  • a recess 62 is formed on the inner wall surface of the chamber 6. That is, a central portion of the inner wall surface of the chamber side 61 to which the reflection ring 69 and the gas ring 90 are not mounted, an upper end surface of the reflection ring 69, and a recess 62 surrounded by the lower end surface of the gas ring 90 are formed.
  • the recess 62 is formed in an annular shape along the horizontal direction on the inner wall surface of the chamber 6 and surrounds the holding portion 7 that holds the semiconductor wafer W.
  • the chamber side portion 61 is provided with a transport opening (furnace port) 66 for carrying in and out of the semiconductor wafer W into and out of the chamber 6.
  • the transport opening 66 can be opened and closed by a gate valve 185.
  • the transport opening 66 is communicatively connected to the outer peripheral surface of the recess 62. Therefore, when the gate valve 185 opens the transport opening 66, the semiconductor wafer W is carried in from the transport opening 66 through the recess 62 into the heat treatment space 65 and the semiconductor wafer W is carried out from the heat treatment space 65. It can be performed. Further, when the gate valve 185 closes the transport opening 66, the heat treatment space 65 in the chamber 6 becomes a closed space.
  • a through hole 61a is bored in the chamber side portion 61.
  • a radiation thermometer 20 is attached to a portion of the outer wall surface of the chamber side 61 where the through hole 61a is provided.
  • the through hole 61a is a cylindrical hole for guiding the infrared light emitted from the lower surface of the semiconductor wafer W held by the susceptor 74, which will be described later, to the radiation thermometer 20.
  • the through hole 61a is provided so as to be inclined with respect to the horizontal direction so that the axis in the through direction intersects the main surface of the semiconductor wafer W held by the susceptor 74.
  • a transparent window 21 made of a barium fluoride material that transmits infrared light in a wavelength region that can be measured by the radiation thermometer 20 is attached to the end of the through hole 61a on the side facing the heat treatment space 65.
  • a gas discharge port 81 for supplying the processing gas to the heat treatment space 65 is formed in the upper part of the inner wall of the chamber 6.
  • the gas discharge port 81 is formed between the gas ring 90 and the upper chamber window 63.
  • the gas discharge port 81 is communicated with and connected to the gas supply pipe 83 via the internal space of the gas ring 90.
  • the gas supply pipe 83 is connected to the processing gas supply source 85.
  • a valve 84 is inserted in the middle of the path of the gas supply pipe 83. When the valve 84 is opened, the processing gas is supplied from the processing gas supply source 85 to the gas ring 90.
  • a buffer space and a labyrinth structure are provided in the internal space of the gas ring 90.
  • the processing gas supplied from the processing gas supply source 85 to the gas ring 90 passes through the internal space of the gas ring 90, so that the flow velocity along the radial and circumferential directions of the chamber 6 is reduced, and the gas discharge port 81 Is uniformly discharged into the heat treatment space 65.
  • the treatment gas for example, an inert gas such as nitrogen (N 2 ), a reactive gas such as hydrogen (H 2 ) or ammonia (NH 3 ), or a mixed gas in which they are mixed can be used (this). Nitrogen gas in the embodiment).
  • the processing gas supply source 85 can also supply helium (He) or hydrogen as a cooling gas.
  • a gas exhaust hole 86 for exhausting the gas in the heat treatment space 65 is formed in the lower part of the inner wall of the chamber 6.
  • the gas exhaust hole 86 is formed at a position below the recess 62, and may be provided in the reflection ring 69.
  • the gas exhaust hole 86 is communicatively connected to the gas exhaust pipe 88 via a buffer space 87 formed in an annular shape inside the side wall of the chamber 6.
  • the gas exhaust pipe 88 is connected to the exhaust unit 190.
  • a valve 89 is inserted in the middle of the path of the gas exhaust pipe 88. When the valve 89 is opened, the gas in the heat treatment space 65 is discharged from the gas exhaust hole 86 to the gas exhaust pipe 88 via the buffer space 87.
  • the processing gas supply source 85 and the exhaust unit 190 may be a mechanism provided in the heat treatment apparatus 1, or may be a utility of a factory in which the heat treatment apparatus 1 is installed.
  • a gas exhaust pipe 191 for discharging the gas in the heat treatment space 65 is also connected to the tip of the transport opening 66.
  • the gas exhaust pipe 191 is connected to the exhaust unit 190 via a valve 192. By opening the valve 192, the gas in the chamber 6 is exhausted through the transfer opening 66.
  • FIG. 2 is a perspective view showing the overall appearance of the holding portion 7.
  • the holding portion 7 includes a base ring 71, a connecting portion 72, and a susceptor 74.
  • the base ring 71, the connecting portion 72 and the susceptor 74 are all made of quartz. That is, the entire holding portion 7 is made of quartz.
  • the base ring 71 is an arc-shaped quartz member in which a part is missing from the ring shape. This missing portion is provided to prevent interference between the transfer arm 11 of the transfer mechanism 10 described later and the base ring 71.
  • the base ring 71 By placing the base ring 71 on the bottom surface of the recess 62, the base ring 71 is supported on the wall surface of the chamber 6 (see FIG. 1).
  • a plurality of connecting portions 72 (four in the present embodiment) are erected on the upper surface of the base ring 71 along the circumferential direction of the ring shape.
  • the connecting portion 72 is also a quartz member, and is fixed to the base ring 71 by welding.
  • FIG. 3 is a plan view of the susceptor 74.
  • FIG. 4 is a cross-sectional view of the susceptor 74.
  • the susceptor 74 includes a holding plate 75, a guide ring 76 and a plurality of substrate support pins 77.
  • the holding plate 75 is a substantially circular flat plate-shaped member made of quartz. The diameter of the holding plate 75 is larger than the diameter of the semiconductor wafer W. That is, the holding plate 75 has a plane size larger than that of the semiconductor wafer W.
  • a guide ring 76 is installed on the upper peripheral edge of the holding plate 75.
  • the guide ring 76 is a ring-shaped member having an inner diameter larger than the diameter of the semiconductor wafer W. For example, when the diameter of the semiconductor wafer W is ⁇ 300 mm, the inner diameter of the guide ring 76 is ⁇ 320 mm.
  • the inner circumference of the guide ring 76 is a tapered surface that widens upward from the holding plate 75.
  • the guide ring 76 is made of quartz similar to the holding plate 75.
  • the guide ring 76 may be welded to the upper surface of the holding plate 75, or may be fixed to the holding plate 75 by a separately processed pin or the like. Alternatively, the holding plate 75 and the guide ring 76 may be processed as an integral member.
  • the region inside the guide ring 76 on the upper surface of the holding plate 75 is a flat holding surface 75a for holding the semiconductor wafer W.
  • a plurality of substrate support pins 77 are erected on the holding surface 75a of the holding plate 75. In the present embodiment, a total of 12 substrate support pins 77 are erected at every 30 ° along the circumference of the outer circumference circle (inner circumference circle of the guide ring 76) of the holding surface 75a and the concentric circles.
  • the diameter of the circle in which the 12 substrate support pins 77 are arranged is smaller than the diameter of the semiconductor wafer W, and if the diameter of the semiconductor wafer W is ⁇ 300 mm, the diameter is ⁇ 270 mm to ⁇ 280 mm (this implementation). In the form, it is ⁇ 270 mm).
  • Each substrate support pin 77 is made of quartz.
  • the plurality of substrate support pins 77 may be provided on the upper surface of the holding plate 75 by welding, or may be processed integrally with the holding plate 75.
  • the four connecting portions 72 erected on the base ring 71 and the peripheral edge portion of the holding plate 75 of the susceptor 74 are fixed by welding. That is, the susceptor 74 and the base ring 71 are fixedly connected by the connecting portion 72.
  • the base ring 71 of the holding portion 7 is supported on the wall surface of the chamber 6, so that the holding portion 7 is mounted on the chamber 6.
  • the holding plate 75 of the susceptor 74 is in a horizontal posture (a posture in which the normal line coincides with the vertical direction). That is, the holding surface 75a of the holding plate 75 is a horizontal plane.
  • the semiconductor wafer W carried into the chamber 6 is placed and held in a horizontal posture on the susceptor 74 of the holding portion 7 mounted on the chamber 6.
  • the semiconductor wafer W is supported by the twelve substrate support pins 77 erected on the holding plate 75 and held by the susceptor 74. More precisely, the upper ends of the 12 substrate support pins 77 come into contact with the lower surface of the semiconductor wafer W to support the semiconductor wafer W. Since the heights of the 12 substrate support pins 77 (distance from the upper end of the substrate support pins 77 to the holding surface 75a of the holding plate 75) are uniform, the semiconductor wafer W is placed in a horizontal position by the 12 substrate support pins 77. Can be supported.
  • the semiconductor wafer W is supported by a plurality of substrate support pins 77 from the holding surface 75a of the holding plate 75 at a predetermined interval.
  • the thickness of the guide ring 76 is larger than the height of the substrate support pin 77. Therefore, the horizontal misalignment of the semiconductor wafer W supported by the plurality of substrate support pins 77 is prevented by the guide ring 76.
  • the holding plate 75 of the susceptor 74 is formed with an opening 78 that penetrates vertically.
  • the opening 78 is provided so that the radiation thermometer 20 receives the synchrotron radiation (infrared light) radiated from the lower surface of the semiconductor wafer W. That is, the radiation thermometer 20 receives the light radiated from the lower surface of the semiconductor wafer W through the transparent window 21 mounted in the opening 78 and the through hole 61a of the chamber side portion 61, and measures the temperature of the semiconductor wafer W. Measure.
  • the holding plate 75 of the susceptor 74 is provided with four through holes 79 through which the lift pin 12 of the transfer mechanism 10 described later penetrates for the transfer of the semiconductor wafer W.
  • FIG. 5 is a plan view of the transfer mechanism 10.
  • FIG. 6 is a side view of the transfer mechanism 10.
  • the transfer mechanism 10 includes two transfer arms 11.
  • the transfer arm 11 has an arc shape that generally follows the annular recess 62.
  • Two lift pins 12 are erected on each transfer arm 11.
  • the transfer arm 11 and the lift pin 12 are made of quartz.
  • Each transfer arm 11 is rotatable by a horizontal movement mechanism 13.
  • the horizontal movement mechanism 13 has a transfer operation position (solid line position in FIG. 5) for transferring the semiconductor wafer W to the holding portion 7 and the semiconductor wafer W held by the holding portion 7. It is horizontally moved to and from the retracted position (two-point chain line position in FIG. 5) that does not overlap in a plan view.
  • the horizontal movement mechanism 13 may be one in which each transfer arm 11 is rotated by an individual motor, or a pair of transfer arms 11 are interlocked and rotated by one motor using a link mechanism. It may be something to move.
  • the pair of transfer arms 11 are moved up and down together with the horizontal movement mechanism 13 by the elevating mechanism 14.
  • the elevating mechanism 14 raises the pair of transfer arms 11 at the transfer operation position, a total of four lift pins 12 pass through the through holes 79 (see FIGS. 2 and 3) formed in the susceptor 74, and the lift pins The upper end of 12 protrudes from the upper surface of the susceptor 74.
  • the elevating mechanism 14 lowers the pair of transfer arms 11 at the transfer operation position, the lift pin 12 is pulled out from the through hole 79, and the horizontal movement mechanism 13 moves the pair of transfer arms 11 so as to open each.
  • the transfer arm 11 moves to the retracted position.
  • the retracted position of the pair of transfer arms 11 is directly above the base ring 71 of the holding portion 7. Since the base ring 71 is placed on the bottom surface of the recess 62, the retracted position of the transfer arm 11 is inside the recess 62.
  • An exhaust mechanism (not shown) is also provided in the vicinity of the portion where the drive unit (horizontal movement mechanism 13 and elevating mechanism 14) of the transfer mechanism 10 is provided, and the atmosphere around the drive unit of the transfer mechanism 10 is provided. Is configured to be discharged to the outside of the chamber 6.
  • the chamber 6 is provided with a radiation thermometer 20 and a temperature sensor 29.
  • the radiation thermometer 20 is provided obliquely below the semiconductor wafer W held by the susceptor 74.
  • the radiation thermometer 20 receives infrared light radiated from the lower surface of the semiconductor wafer W and measures the temperature of the lower surface from the intensity of the infrared light.
  • the temperature sensor 29 is configured by using a thermocouple.
  • the temperature sensor 29 is attached to the inner wall surface of the chamber 6.
  • the temperature sensor 29 measures the ambient temperature in the chamber 6.
  • the flash heating unit 5 provided above the chamber 6 is provided inside the housing 51 so as to cover a light source composed of a plurality of (30 in this embodiment) xenon flash lamp FL and the upper part of the light source.
  • the reflector 52 and the reflector 52 are provided.
  • a lamp light radiation window 53 is attached to the bottom of the housing 51 of the flash heating unit 5.
  • the lamp light emitting window 53 constituting the floor portion of the flash heating unit 5 is a plate-shaped quartz window made of quartz.
  • Each of the plurality of flash lamps FL is a rod-shaped lamp having a long cylindrical shape, and the longitudinal direction thereof is along the main surface of the semiconductor wafer W held by the holding portion 7 (that is, along the horizontal direction). They are arranged in a plane so as to be parallel to each other. Therefore, the plane formed by the arrangement of the flash lamps FL is also a horizontal plane. The region where the plurality of flash lamps FL are arranged is larger than the plane size of the semiconductor wafer W.
  • the xenon flash lamp FL has a cylindrical glass tube (discharge tube) in which xenon gas is sealed inside and an anode and a cathode connected to a condenser are arranged at both ends thereof, and on the outer peripheral surface of the glass tube. It is provided with an attached trigger electrode. Since xenon gas is electrically an insulator, even if electric charges are accumulated in the condenser, electricity does not flow in the glass tube under normal conditions. However, when a high voltage is applied to the trigger electrode to break the insulation, the electricity stored in the capacitor instantly flows into the glass tube, and light is emitted by the excitation of xenon atoms or molecules at that time.
  • the electrostatic energy stored in the capacitor in advance is converted into an extremely short optical pulse of 0.1 millisecond to 100 millisecond, so that the halogen lamp HL is continuously lit. It has the feature that it can irradiate extremely strong light compared to a light source. That is, the flash lamp FL is a pulsed lamp that emits light instantaneously in an extremely short time of less than 1 second. The light emission time of the flash lamp FL can be adjusted by the coil constant of the lamp power supply that supplies power to the flash lamp FL.
  • the reflector 52 is provided above the plurality of flash lamps FL so as to cover all of them.
  • the basic function of the reflector 52 is to reflect the flash light emitted from the plurality of flash lamps FL toward the heat treatment space 65.
  • the reflector 52 is made of an aluminum alloy plate, and its surface (the surface facing the flash lamp FL) is roughened by blasting.
  • the halogen heating unit 4 provided below the chamber 6 contains a plurality of halogen lamps HL (40 in this embodiment) inside the housing 41.
  • the halogen heating unit 4 is a light irradiation unit that heats the semiconductor wafer W by irradiating the heat treatment space 65 with light from below the chamber 6 through the lower chamber window 64 by a plurality of halogen lamps HL.
  • FIG. 7 is a plan view showing the arrangement of a plurality of halogen lamps HL.
  • the 40 halogen lamps HL are arranged in two upper and lower stages. Twenty halogen lamps HL are arranged in the upper stage near the holding portion 7, and 20 halogen lamps HL are also arranged in the lower stage farther from the holding portion 7 than in the upper stage.
  • Each halogen lamp HL is a rod-shaped lamp having a long cylindrical shape.
  • the 20 halogen lamps HL in both the upper and lower stages are arranged so that their longitudinal directions are parallel to each other along the main surface of the semiconductor wafer W held by the holding portion 7 (that is, along the horizontal direction). There is. Therefore, the plane formed by the arrangement of the halogen lamps HL in both the upper and lower stages is a horizontal plane.
  • the arrangement density of the halogen lamp HL in the region facing the peripheral edge portion is higher than the region facing the central portion of the semiconductor wafer W held by the holding portion 7 in both the upper and lower stages.
  • the arrangement pitch of the halogen lamp HL is shorter in the peripheral portion than in the central portion of the lamp arrangement. Therefore, it is possible to irradiate a peripheral portion of the semiconductor wafer W, which tends to have a temperature drop during heating by light irradiation from the halogen heating unit 4, with a larger amount of light.
  • the lamp group consisting of the upper halogen lamp HL and the lamp group consisting of the lower halogen lamp HL are arranged so as to intersect in a grid pattern. That is, a total of 40 halogen lamps HL are arranged so that the longitudinal direction of the 20 halogen lamps HL arranged in the upper stage and the longitudinal direction of the 20 halogen lamps HL arranged in the lower stage are orthogonal to each other. There is.
  • the halogen lamp HL is a filament type light source that incandescents the filament and emits light by energizing the filament arranged inside the cylindrical glass tube. Inside the glass tube, a gas in which a small amount of a halogen element (iodine, bromine, etc.) is introduced into an inert gas such as nitrogen or argon is sealed. By introducing the halogen element, it becomes possible to set the temperature of the filament to a high temperature while suppressing the breakage of the filament. Therefore, the halogen lamp HL has a characteristic that it has a longer life and can continuously irradiate strong light as compared with a normal incandescent lamp.
  • a gas in which a small amount of a halogen element iodine, bromine, etc.
  • the halogen lamp HL is a continuously lit lamp that continuously emits light for at least 1 second or longer. Further, since the halogen lamp HL is a rod-shaped lamp, it has a long life, and by arranging the halogen lamp HL along the horizontal direction, the radiation efficiency to the upper semiconductor wafer W becomes excellent.
  • a reflector 43 is provided under the two-stage halogen lamp HL in the housing 41 of the halogen heating unit 4 (FIG. 1).
  • the reflector 43 reflects the light emitted from the plurality of halogen lamps HL toward the heat treatment space 65.
  • the control unit 3 controls the above-mentioned various operating mechanisms provided in the heat treatment apparatus 1.
  • the configuration of the control unit 3 as hardware is the same as that of a general computer. That is, the control unit 3 stores a CPU, which is a circuit that performs various arithmetic processes, a ROM, which is a read-only memory for storing basic programs, a RAM, which is a read / write memory for storing various information, and control software and data. It has a magnetic disk to store.
  • the processing in the heat treatment apparatus 1 proceeds when the CPU of the control unit 3 executes a predetermined processing program.
  • the heat treatment apparatus 1 prevents an excessive temperature rise of the halogen heating unit 4, the flash heating unit 5, and the chamber 6 due to the thermal energy generated from the halogen lamp HL and the flash lamp FL during the heat treatment of the semiconductor wafer W. Therefore, it has various cooling structures.
  • a water cooling pipe (not shown) is provided on the wall of the chamber 6.
  • the halogen heating unit 4 and the flash heating unit 5 have an air-cooled structure in which a gas flow is formed inside to exhaust heat.
  • air is also supplied to the gap between the upper chamber window 63 and the lamp light radiation window 53 to cool the flash heating unit 5 and the upper chamber window 63.
  • FIG. 8 is a flowchart showing a processing procedure of the semiconductor wafer W in the heat treatment apparatus 1.
  • the semiconductor wafer W to be processed here is a semiconductor substrate to which impurities (ions) have been added by the ion implantation method. Activation of the impurities is carried out by flash light irradiation heat treatment (annealing) by the heat treatment apparatus 1.
  • the processing procedure of the heat treatment apparatus 1 described below proceeds by the control unit 3 controlling each operation mechanism of the heat treatment apparatus 1.
  • the valve 84 for air supply is opened, and the valves 89 and 192 for exhaust are opened to start air supply and exhaust to the inside of the chamber 6.
  • nitrogen gas as a processing gas is supplied from the processing gas supply source 85 to the gas ring 90, and the nitrogen gas that has passed through the internal space of the gas ring 90 is sent from the gas discharge port 81 to the heat treatment space 65. It is discharged.
  • the valve 89 is opened, the gas in the chamber 6 is exhausted from the gas exhaust hole 86. As a result, the nitrogen gas supplied from the upper part of the heat treatment space 65 in the chamber 6 flows downward and is exhausted from the lower part of the heat treatment space 65.
  • valve 192 when the valve 192 is opened, the gas in the chamber 6 is also exhausted from the transport opening 66. Further, the atmosphere around the drive unit of the transfer mechanism 10 is also exhausted by the exhaust mechanism (not shown).
  • Step S1 the gate valve 185 is opened to open the transfer opening 66, and the semiconductor wafer W after ion implantation is carried into the heat treatment space 65 in the chamber 6 through the transfer opening 66 by a transfer robot outside the apparatus.
  • the atmosphere outside the apparatus may be involved with the loading of the semiconductor wafer W, but since the nitrogen gas continues to be supplied to the chamber 6, the nitrogen gas flows out from the transport opening 66, and so on. It is possible to minimize the entrainment of an external atmosphere.
  • the semiconductor wafer W carried in by the transfer robot advances to a position directly above the holding portion 7 and stops. Then, the pair of transfer arms 11 of the transfer mechanism 10 move horizontally from the retracted position to the transfer operation position and rise, so that the lift pin 12 protrudes from the upper surface of the holding plate 75 of the susceptor 74 through the through hole 79. Receives the semiconductor wafer W. At this time, the lift pin 12 rises above the upper end of the substrate support pin 77.
  • the transfer robot exits the heat treatment space 65, and the transfer opening 66 is closed by the gate valve 185. Then, as the pair of transfer arms 11 descend, the semiconductor wafer W is handed over from the transfer mechanism 10 to the susceptor 74 of the holding portion 7 and held in a horizontal posture from below.
  • the semiconductor wafer W is supported by a plurality of substrate support pins 77 erected on the holding plate 75 and held by the susceptor 74. Further, the semiconductor wafer W is held by the holding portion 7 with the surface on which the pattern is formed and the impurities are injected as the upper surface.
  • a predetermined distance is formed between the back surface (main surface opposite to the front surface) of the semiconductor wafer W supported by the plurality of substrate support pins 77 and the holding surface 75a of the holding plate 75.
  • the pair of transfer arms 11 lowered to the lower side of the susceptor 74 are retracted to the retracted position, that is, inside the recess 62 by the horizontal movement mechanism 13.
  • FIG. 9 is a diagram showing changes in the surface temperature of the semiconductor wafer W.
  • the 40 halogen lamps HL of the halogen heating portion 4 are turned on all at once to prepare. Heating (assisted heating) is started (step S2).
  • the halogen light emitted from the halogen lamp HL passes through the lower chamber window 64 and the susceptor 74 made of quartz and irradiates the lower surface of the semiconductor wafer W.
  • the semiconductor wafer W is preheated and the temperature rises. Since the transfer arm 11 of the transfer mechanism 10 is retracted inside the recess 62, it does not interfere with heating by the halogen lamp HL.
  • the temperature of the semiconductor wafer W is measured by the radiation thermometer 20. That is, the radiation thermometer 20 receives infrared light radiated from the lower surface of the semiconductor wafer W held by the susceptor 74 through the opening 78 through the transparent window 21 and measures the wafer temperature during temperature rise. The measured temperature of the semiconductor wafer W is transmitted to the control unit 3.
  • the control unit 3 controls the output of the halogen lamp HL while monitoring whether or not the temperature of the semiconductor wafer W, which is raised by light irradiation from the halogen lamp HL, has reached a predetermined preheating temperature T1.
  • the control unit 3 feedback-controls the output of the halogen lamp HL so that the temperature of the semiconductor wafer W becomes the preheating temperature T1 based on the measured value by the radiation thermometer 20.
  • the preheating temperature T1 is about 200 ° C. to 800 ° C., preferably about 350 ° C. to 600 ° C. (600 ° C. in the present embodiment) so that impurities added to the semiconductor wafer W are not diffused by heat. ..
  • the control unit 3 After the temperature of the semiconductor wafer W reaches the preheating temperature T1, the control unit 3 maintains the semiconductor wafer W at the preheating temperature T1 for a while. Specifically, the control unit 3 adjusts the output of the halogen lamp HL at the time t2 when the temperature of the semiconductor wafer W measured by the radiation thermometer 20 reaches the preheating temperature T1 to substantially reserve the temperature of the semiconductor wafer W. The heating temperature is maintained at T1.
  • the entire semiconductor wafer W is uniformly heated to the preheating temperature T1.
  • the temperature of the peripheral portion of the semiconductor wafer W which is more likely to dissipate heat, tends to be lower than that of the central portion.
  • the region facing the peripheral edge portion is higher than the region facing the central portion of the substrate W. Therefore, the amount of light irradiated to the peripheral portion of the semiconductor wafer W where heat dissipation is likely to occur increases, and the in-plane temperature distribution of the semiconductor wafer W in the preheating step can be made uniform.
  • the flash lamp FL of the flash heating unit 5 irradiates the surface of the semiconductor wafer W held by the susceptor 74 with flash light (step). S3). At this time, a part of the flash light radiated from the flash lamp FL goes directly into the chamber 6, and the other part is once reflected by the reflector 52 and then goes into the chamber 6, and these flash lights The semiconductor wafer W is flash-heated by irradiation.
  • the surface temperature of the semiconductor wafer W can be raised in a short time. That is, the flash light emitted from the flash lamp FL has an extremely short irradiation time of 0.1 millisecond or more and 100 millisecond or less, in which the electrostatic energy stored in the capacitor in advance is converted into an extremely short optical pulse. It is a strong flash. Then, the surface temperature of the semiconductor wafer W flash-heated by the flash light irradiation from the flash lamp FL momentarily rises to the processing temperature T2 of 1000 ° C. or higher, and the impurities injected into the semiconductor wafer W are activated. After that, the surface temperature drops rapidly.
  • the impurities are activated while suppressing the diffusion of the impurities injected into the semiconductor wafer W due to the heat. Can be done. Since the time required for the activation of impurities is extremely short compared to the time required for the thermal diffusion, the activation can be performed even for a short time in which diffusion of about 0.1 msecond to 100 msecond does not occur. Complete.
  • the halogen lamp HL is turned off at time t4 when a predetermined time (for example, 2 seconds) has elapsed after the flash heat treatment is completed.
  • a predetermined time for example, 2 seconds
  • the supply of the cooling gas is started (step S4).
  • helium gas is supplied as cooling gas from the processing gas supply source 85 to the gas ring 90 at the time t4 when the halogen lamp HL is turned off.
  • the helium gas supplied to the gas ring 90 is supplied from the gas discharge port 81 to the heat treatment space 65 in the chamber 6. Further, the exhaust from the gas exhaust hole 86 is also continuously performed.
  • Helium gas has high thermal conductivity (about 0.144 W / m ⁇ K at 0 ° C). Therefore, helium gas has a high cooling capacity.
  • the inner wall surface of the gas ring 90 separated from the wall body is not sufficiently cooled. Therefore, the inner wall surface of the gas ring 90 tends to be heated to a high temperature by light irradiation from the halogen lamp HL and the flash lamp FL, and may be discolored by the reaction product derived from the film of the semiconductor wafer W which has been heated.
  • helium gas having a high cooling ability is supplied into the chamber 6 after flash heating, not only the semiconductor wafer W but also the components of the chamber 6 including the gas ring 90 are rapidly cooled. It will be. Thereby, discoloration of the gas ring 90 can be prevented.
  • the ambient temperature in the chamber 6 is measured by the temperature sensor 29.
  • the supply of helium gas is continued until the ambient temperature in the chamber 6 measured by the temperature sensor 29 drops to a predetermined temperature (for example, 200 ° C. to 250 ° C.) (step S5). Then, at the time t5 when the ambient temperature in the chamber 6 measured by the temperature sensor 29 drops to a predetermined temperature, the process proceeds from step S5 to step S6, and the supply of the cooling gas is stopped.
  • a predetermined temperature for example, 200 ° C. to 250 ° C.
  • step S7 the pressure inside the chamber 6 is reduced. Specifically, the valve 84 is closed to stop the gas supply to the chamber 6, and only the exhaust from the chamber 6 is executed to reduce the pressure in the chamber 6. By reducing the pressure inside the chamber 6, the helium gas used for cooling is discharged from the chamber 6.
  • step S8 After the inside of the chamber 6 is depressurized to a predetermined pressure (for example, about 100 Pa), nitrogen gas is supplied into the chamber 6 and the inside of the chamber 6 is restored to the atmospheric pressure (step S8). At this time, the valve 84 is opened again, nitrogen gas is supplied from the processing gas supply source 85, and nitrogen gas is supplied into the chamber 6 from the gas discharge port 81. As a result, the inside of the chamber 6 becomes a nitrogen atmosphere again.
  • a predetermined pressure for example, about 100 Pa
  • the cooled semiconductor wafer W is carried out from the chamber 6 (step S9).
  • the pair of transfer arms 11 of the transfer mechanism 10 horizontally move from the retracted position to the transfer operation position again and rise, so that the lift pin 12 is moved to the susceptor 74.
  • the semiconductor wafer W protruding from the upper surface and cooled is received from the susceptor 74.
  • the transfer opening 66 closed by the gate valve 185 is opened, the semiconductor wafer W mounted on the lift pin 12 is carried out by a transfer robot outside the apparatus, and the semiconductor wafer W is processed in the heat treatment apparatus 1. Complete.
  • helium gas having a high cooling ability is supplied into the chamber 6 as a cooling gas.
  • the inside of the chamber 6 including the semiconductor wafer W and the gas ring 90 can be cooled efficiently and quickly.
  • the cooling time of the semiconductor wafer W can be shortened as compared with natural cooling, and the throughput can be improved.
  • discoloration of the gas ring 90 can be prevented.
  • the supply of the cooling gas is stopped when the ambient temperature in the chamber 6 is lowered to a predetermined temperature. If the cooling gas is continuously supplied for a long period of time, the components of the chamber 6 will be excessively cooled. Then, when the subsequent processing of the new semiconductor wafer W is performed, the semiconductor wafer W is held by the overcooled susceptor 74, and the temperature history of the plurality of semiconductor wafers W becomes non-uniform. Occurs. Therefore, the supply of the cooling gas is stopped when the ambient temperature in the chamber 6 is lowered to a predetermined temperature so that the inside of the chamber 6 is not excessively cooled.
  • the present invention can be modified in various ways other than those described above as long as the gist of the present invention is not deviated.
  • helium gas is used as the cooling gas, but the present invention is not limited to this, and the cooling gas may be a gas having a higher thermal conductivity than nitrogen. That is, the thermal conductivity of nitrogen gas is about 0.024 W / m ⁇ K at 0 ° C., and a gas having a thermal conductivity higher than that may be supplied into the chamber 6 as a cooling gas.
  • the gas having a thermal conductivity higher than that of nitrogen other than helium include hydrogen (about 0.168 W / m ⁇ K at 0 ° C.). Even if hydrogen gas is supplied as a cooling gas into the chamber 6 after the flash heat treatment is completed, the same effect as that of the above embodiment can be obtained.
  • the supply of the cooling gas is started at the same time when the halogen lamp HL is turned off, but the supply timing of the cooling gas is not limited to this, and the flash light is irradiated from the flash lamp FL. It may be after the time point (time t3 or later). Therefore, for example, the supply of the cooling gas may be started at the same time as the flash lamp FL emits light. However, even if the halogen lamp HL is lit for a predetermined time (the period from time t3 to time t4) after the flash light is irradiated and the flash lamp FL emits light and the supply of cooling gas is started at the same time, the halogen lamp is used.
  • Heating by HL and cooling by cooling gas are performed at the same time, which is not efficient. Therefore, as in the above embodiment, it is possible to efficiently cool the inside of the chamber 6 by starting the supply of the cooling gas at the same time when the halogen lamp HL is turned off. Also, it is prohibited to supply cooling gas before irradiating with flash light. This is because if the cooling gas is supplied before the flash light is irradiated, the temperature of the semiconductor wafer W may be lower than the preheating temperature T1 at the time of the flash light irradiation.
  • the flow velocity of the cooling gas in the chamber 6 may be increased by controlling the supply flow rate of the cooling gas from the gas ring 90 and the exhaust pressure from the gas exhaust hole 86.
  • the supply flow rate of the cooling gas can be up to 150 liters / minute.
  • the flash heating unit 5 is provided with 30 flash lamp FLs, but the present invention is not limited to this, and the number of flash lamp FLs can be any number. .. Further, the flash lamp FL is not limited to the xenon flash lamp, and may be a krypton flash lamp. Further, the number of halogen lamps HL provided in the halogen heating unit 4 is not limited to 40, and can be any number.
  • the semiconductor wafer W is preheated by using a filament type halogen lamp HL as a continuous lighting lamp that continuously emits light for 1 second or longer, but the present invention is not limited to this.
  • a discharge type arc lamp for example, a xenon arc lamp
  • a continuous lighting lamp to perform preheating.
  • the substrate to be processed by the heat treatment apparatus 1 is not limited to the semiconductor wafer, and may be a glass substrate used for a flat panel display such as a liquid crystal display device or a substrate for a solar cell.

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Abstract

Selon la présente invention, de la lumière est émise sous la forme de flashs d'une lampe flash vers une surface d'une plaquette semi-conductrice qui a été préchauffée par irradiation de lumière provenant d'une lampe halogène. Lorsqu'elle est irradiée avec la lumière sous la forme de flashs, la température de la surface de la plaquette semi-conductrice augmente rapidement en une courte période de temps. Dès que la lampe halogène est éteinte à la suite de l'achèvement de l'irradiation par la lumière flash, de l'hélium gazeux ayant une conductibilité thermique plus élevée que celle de l'azote est apporté dans une chambre en tant que gaz de refroidissement. Grâce à l'apport d'hélium gazeux qui a une capacité de refroidissement élevée, il est possible de refroidir efficacement et rapidement l'intérieur de la chambre qui loge une plaquette semi-conductrice et un anneau de gaz.
PCT/JP2020/031834 2019-09-11 2020-08-24 Procédé de traitement thermique et appareil de traitement thermique WO2021049283A1 (fr)

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JP2019165294A JP7377653B2 (ja) 2019-09-11 2019-09-11 熱処理方法および熱処理装置

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH05275433A (ja) * 1992-03-27 1993-10-22 Rohm Co Ltd 半導体装置の製法
JP2003045817A (ja) * 2001-07-27 2003-02-14 Dainippon Screen Mfg Co Ltd 基板の熱処理装置
JP2010114207A (ja) * 2008-11-05 2010-05-20 Dainippon Screen Mfg Co Ltd 熱処理装置

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4481528B2 (ja) 2001-06-22 2010-06-16 株式会社東芝 半導体製造装置及び半導体装置の製造方法
KR100439276B1 (ko) 2003-11-24 2004-07-30 코닉 시스템 주식회사 급속열처리 장치

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH05275433A (ja) * 1992-03-27 1993-10-22 Rohm Co Ltd 半導体装置の製法
JP2003045817A (ja) * 2001-07-27 2003-02-14 Dainippon Screen Mfg Co Ltd 基板の熱処理装置
JP2010114207A (ja) * 2008-11-05 2010-05-20 Dainippon Screen Mfg Co Ltd 熱処理装置

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