WO2024018786A1 - Laser annealing apparatus, laser annealing method, and laser annealing program - Google Patents

Laser annealing apparatus, laser annealing method, and laser annealing program Download PDF

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Publication number
WO2024018786A1
WO2024018786A1 PCT/JP2023/022020 JP2023022020W WO2024018786A1 WO 2024018786 A1 WO2024018786 A1 WO 2024018786A1 JP 2023022020 W JP2023022020 W JP 2023022020W WO 2024018786 A1 WO2024018786 A1 WO 2024018786A1
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Prior art keywords
laser
semiconductor wafer
pulse
temperature
activation
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PCT/JP2023/022020
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French (fr)
Japanese (ja)
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雅史 萬
康弘 岡田
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住友重機械工業株式会社
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Publication of WO2024018786A1 publication Critical patent/WO2024018786A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/352—Working by laser beam, e.g. welding, cutting or boring for surface treatment
    • B23K26/354—Working by laser beam, e.g. welding, cutting or boring for surface treatment by melting
    • 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
    • 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
    • H01L21/268—Bombardment with radiation with high-energy radiation using electromagnetic radiation, e.g. laser radiation

Definitions

  • the present invention relates to a laser annealing device and the like.
  • Patent Document 1 discloses a laser annealing technique in which a semiconductor wafer is irradiated with laser light oscillated by a laser device. This technology, which aims to form extremely shallow p-n junctions, activates dopants added just below the surface of the semiconductor wafer by irradiating it with laser light strong enough not to melt the semiconductor wafer. Further, the subsequent "low temperature rapid thermal annealing" repairs damage to the crystals of the semiconductor wafer.
  • laser annealing unlike Patent Document 1, it is also common to repair damage caused by dopant ion implantation by melting the surface of the semiconductor wafer. Thus, laser annealing has two different roles: repairing damage by melting the surface of the semiconductor wafer and activating dopants implanted into the semiconductor wafer. As disclosed in Patent Document 2, in order to effectively achieve surface melting and subsurface activation, multiple different modes of laser light are required, and typically multiple different laser devices are required. It was necessary to prepare.
  • the present invention has been made in view of these circumstances, and it is an object of the present invention to provide a laser annealing device and the like that can effectively melt the surface of a semiconductor wafer and activate the subsurface of the semiconductor wafer using a single pulse laser device. purpose.
  • a laser annealing apparatus irradiates a semiconductor wafer with laser pulses oscillated by a pulsed laser apparatus, and heats the surface of the semiconductor wafer above its melting point using a plurality of laser pulses.
  • a surface melting step in which the semiconductor wafer is melted, and a laser pulse is continuously irradiated to the semiconductor wafer from the surface melting step, and the subsurface of the semiconductor wafer is raised to a predetermined activation temperature or higher for at least a predetermined time using a plurality of laser pulses. heating and activating dopants added below the surface of the semiconductor wafer.
  • one pulsed laser device continues to irradiate the semiconductor wafer with laser pulses through successive surface melting steps and activation steps, thereby performing both surface melting and subsurface activation.
  • the surface of the semiconductor wafer melted in the surface melting step continues to be intermittently irradiated with laser pulses even in the activation step, but due to heat radiation from the surface during the non-pulse period when the laser pulse is not irradiated, the surface of the semiconductor wafer melted during the activation step. This prevents the surface of the semiconductor wafer from becoming overheated. Note that the surface melting step and the activation step may overlap in time.
  • Another aspect of the present invention is a laser annealing method.
  • This method consists of a surface melting step in which the semiconductor wafer is irradiated with laser pulses emitted by a pulsed laser device, and the surface of the semiconductor wafer is heated to a temperature higher than the melting point by multiple laser pulses and melted, and the surface melting step is continued.
  • the semiconductor wafer is irradiated with a laser pulse, and the temperature below the surface of the semiconductor wafer is raised to a predetermined activation temperature or higher for at least a predetermined period of time using multiple laser pulses, thereby activating the dopants added below the surface of the semiconductor wafer. an activation step of activating the method.
  • the present invention also encompasses any combination of the above components and the conversion of these expressions into methods, devices, systems, recording media, computer programs, etc.
  • melting on the surface of a semiconductor wafer and activation below the surface of the semiconductor wafer can be effectively achieved with one pulse laser device.
  • FIG. 1 is a perspective view schematically showing the configuration of a laser annealing device.
  • the configuration of an optical fiber, which is a main part of a fiber laser device, and the principles of laser pulse generation and amplification in the optical fiber are schematically shown.
  • the configuration of a pulse laser device as a fiber laser device is schematically shown.
  • 3 shows the time course of the surface temperature of a semiconductor wafer irradiated with various laser beams.
  • FIG. 1 is a perspective view schematically showing the configuration of a laser annealing apparatus 1 according to an embodiment of the present invention.
  • the laser annealing device 1 is a device that performs an annealing process (heating process) by irradiating the semiconductor wafer 3 with laser pulses generated by a pulsed laser device 2 .
  • the semiconductor wafer 3 fixedly mounted on the wafer table 31 can be driven integrally with the wafer table 31 in the illustrated x direction by a stage device 4, which will be described later. Further, the laser pulse (laser light) oscillated by the pulse laser device 2 can be scanned in the y direction orthogonal to the x direction by a galvano scanner 14, which will be described later. Laser pulses (laser light) scanned in the y direction by the galvano scanner 14 are reflected by a mirror 16, which will be described later, and are incident on the semiconductor wafer 3 in the z direction orthogonal to the x and y directions.
  • the x direction which is the driving direction of the semiconductor wafer 3 is parallel to the X-axis direction (X direction)
  • the y direction which is the scanning direction of the laser pulse (laser light)
  • the z direction which is the direction of incidence of the laser pulse (laser light) on the wafer 3, is parallel to the Z-axis direction (Z direction).
  • the x direction and the X direction will also be referred to as the vertical direction
  • the y direction and the Y direction will also be referred to as the horizontal direction
  • the z direction and the Z direction will also be referred to as the height direction.
  • the pulse laser device 2 is a laser device that oscillates laser pulses at a frequency of 100kHz or higher.
  • the frequency of the laser pulse oscillated by the pulsed laser device 2 is, for example, between 100kHz and 10MHz, and between 500kHz and 5MHz. , more preferably between 700kHz and 3MHz.
  • the frequency of the laser pulse oscillated by the pulse laser device 2 is 800 kHz will be described.
  • the pulse laser device 2 is configured by, for example, a fiber laser device that oscillates laser pulses using an optical fiber.
  • FIG. 2 schematically shows the configuration of an optical fiber 20, which is a main part of the fiber laser device, and the principle of generation and amplification of laser pulses LP in the optical fiber 20.
  • the optical fiber 20 includes a core 201 in the center, a first clad 202 provided around the core 201, and a second clad 203 provided around the first clad 202.
  • the refractive index of the core 201 is higher than the refractive index of the first cladding 202
  • the refractive index of the first cladding 202 is higher than the refractive index of the second cladding 203. That is, the refractive index of the optical fiber 20 is higher as it is closer to the center (core 201) and lower as it is closer to the periphery (second cladding 203).
  • Excitation light EL generated by a light emitting element such as a laser diode enters from one end of the optical fiber 20 (for example, the left end in FIG. 2).
  • This excitation light EL propagates inside the core 201 and the first cladding 202 while being totally reflected at the interface between the first cladding 202 and the second cladding 203.
  • Each time the excitation light EL passes through the core 201 it excites a rare earth element such as Yb added to the core 201, and generates stimulated emission light that becomes the source of the laser pulse LP (laser light).
  • the stimulated emission light generated in the core 201 propagates inside the core 201 while being totally reflected at the interface between the core 201 and the first cladding 202 .
  • mirrors such as total reflection mirrors such as FBG (Fiber Bragg Grating) and output mirrors are formed at both ends of the core 201, and the stimulated emission light that is repeatedly reflected between these mirrors is reflected back to the core.
  • a laser pulse LP laser light
  • This laser pulse LP is formed by being amplified while reciprocating inside the 201. This laser pulse LP is output to the outside of the optical fiber 20 from an output mirror formed at one end of the core 201 (for example, the right end in FIG. 2).
  • FIG. 3 schematically shows the configuration of a pulse laser device 2 as a fiber laser device including an optical fiber 20 as shown in FIG.
  • the pulse laser device 2 includes an excitation light supply section 21, a laser light generation section 22, and a laser light supply section 23.
  • the excitation light supply unit 21 includes a light emitting element 211 such as one or more laser diodes that emits light that is the source of the excitation light EL, and when a plurality of light emitting elements 211 are provided, combines the respective lights to generate the excitation light EL. It includes an optical coupling section 212 to be formed.
  • the excitation light supply section 21 supplies excitation light EL based on the light emitted by the light emitting element 211 to the laser light generation section 22 .
  • the laser light generation unit 22 includes the aforementioned optical fiber 20 to which the excitation light EL is supplied from the input end (left end in FIG. 3), and an input mirror 221 and an output mirror 222 formed at both ends thereof.
  • the input mirror 221 and the output mirror 222 are both formed by FBG at both ends of the core 201, for example. It is preferable that the reflectance of the input mirror 221 provided on the input side (excitation light supply section 21 side) is higher than the reflectance of the output mirror 222 provided on the output side (laser light supply section 23 side).
  • the input mirror 221 is preferably configured as a total reflection mirror that totally reflects the stimulated emission light inside the core 201, which is the source of the laser pulse LP (laser light), toward the output side.
  • the output mirror 222 reflects a part of the stimulated emission light inside the core 201 to the input side, and outputs the rest to the laser light supply section 23 .
  • the laser light supply section 23 includes an optical fiber 231 that guides the laser pulse LP (laser light) generated by the laser light generation section 22 to the output point OP of the pulse laser device 2.
  • the output point of the laser beam generation section 22 may be the output point OP of the pulsed laser device 2, and in that case, it is not necessary to provide the laser beam supply section 23.
  • the laser pulse LP is emitted from the output point OP of the pulse laser device 2 in the X direction.
  • a laser annealing device 1 that guides this laser pulse LP to a semiconductor wafer 3 to be irradiated includes a beam expander 11, a mirror 12, a beam shaping optical element 13, a galvano scanner 14, an f ⁇ lens 15, and a mirror 16. .
  • the beam expander 11 adjusts the laser pulse LP (laser light) emitted from the output point OP of the pulse laser device 2 to a predetermined size (diameter). For example, when the cross section of the laser pulse LP (laser light) emitted from the output point OP of the pulse laser device 2 is approximately circular with a diameter D0, the beam expander 11 adjusts the cross section of the laser pulse LP (laser light) to a predetermined shape. Convert (typically enlarge) into a substantially circular shape with diameter D1.
  • the beam expander 11 is composed of a plurality of lenses 111, 112, and 113.
  • lens 111 is a convex lens
  • lens 112 is a concave lens
  • lens 113 is a convex lens
  • the number and type of lenses and other optical elements constituting the beam expander 11 are arbitrary as long as the desired function and/or effect of adjusting the size of the laser pulse LP can be obtained.
  • the beam expander 11 may be composed of two or more convex lenses and one or more concave lenses arranged in any order, or may be composed only of three or more convex lenses.
  • the mirror 12 reflects the laser pulse LP whose size has been adjusted by the beam expander 11, and changes its traveling direction from the X direction to the Y direction.
  • the beam shaping optical element 13 shapes the laser pulse LP whose size has been adjusted by the beam expander 11, and adjusts its shape and/or intensity distribution.
  • the cross section of the laser pulse LP whose size has been adjusted by the beam expander 11 is approximately circular and has an intensity distribution that follows a Gaussian distribution or a normal distribution, but is shaped by the beam shaping optical element 13 to be approximately rectangular and have an approximately uniform intensity distribution. be done.
  • Such a beam shaping optical element 13 is constituted by, for example, a diffractive optical element (DOE).
  • DOE diffractive optical element
  • the galvano scanner 14 is a laser pulse scanning unit that scans the laser pulse LP shaped by the beam shaping optical element 13 in the y direction (Y direction).
  • the galvano scanner 14 includes a galvano mirror 141 that can reflect the laser pulse LP, and a motor 142 that rotates the galvano mirror 141 around the Z axis.
  • the motor 142 adjusts the rotational position or rotational angle of the galvano mirror 141 around the Z axis, so that the laser pulse LP incident on the galvano mirror 141 is reflected to an arbitrary position in the y direction.
  • the laser pulse scanning unit that scans the laser pulse LP in the y direction is not limited to the galvano scanner 14, but may also be configured by a polygon mirror scanner equipped with a polygon mirror that can be rotated, a MEMS (Micro Electro Mechanical Systems) mirror, etc. good.
  • the scanning direction of the laser pulse LP by the laser pulse scanning unit such as the galvano scanner 14 is not limited to the y direction (Y direction), but may be a direction intersecting the y direction (Y direction) such as the x direction (X direction). , the x direction (X direction) and the y direction (Y direction) may be used.
  • the laser pulse scanning unit such as the galvano scanner 14 can scan the laser pulse LP within the xy plane (XY plane), that is, within the plane of the semiconductor wafer 3, the semiconductor wafer 3 and the wafer table 31 are It is not necessary to provide a stage device 4 that is driven in a direction (X direction) or the like.
  • the f ⁇ lens 15 focuses the laser pulse LP scanned in the y direction (Y direction) by the galvano scanner 14 onto the semiconductor wafer 3 to be annealed.
  • a mirror 16 provided between the f ⁇ lens 15 and the semiconductor wafer 3 reflects the laser pulse LP in the X direction from the f ⁇ lens 15 and irradiates the semiconductor wafer 3 in the Z direction (z direction).
  • the laser pulse LP thus focused on the semiconductor wafer 3 by the f ⁇ lens 15 and the mirror 16 moves in the Y direction within the plane of the semiconductor wafer 3 by scanning in the Y direction by the galvano scanner 14.
  • the size of the laser pulse LP focused on the semiconductor wafer 3 can be arbitrarily designed, it is preferably between 0.10 mm square and 0.15 mm square, and more preferably between 0.12 mm square and 0.13 mm square.
  • the scanning speed of the laser pulse LP in the Y direction on the semiconductor wafer 3 surface can be arbitrarily designed; for example, 100 cm/s and 500 cm. It is preferably between 250 cm/s and 350 cm/s, more preferably between 250 cm/s and 350 cm/s.
  • the laser pulse LP moves relatively within the surface of the semiconductor wafer 3 in the X direction.
  • the laser pulse LP can be moved within the xy plane (in the XY plane), that is, the semiconductor wafer 3. Can scan in 3 planes.
  • the driving direction of the semiconductor wafer 3 by the stage device 4 is not limited to the x direction (X direction), but may also be a direction intersecting the x direction (X direction) such as the y direction (Y direction), or ) and the y direction (Y direction).
  • X direction x direction
  • Y direction y direction
  • a galvanometer that scans the laser pulse LP in the y direction (Y direction) etc.
  • a laser pulse scanning unit such as the scanner 14 may not be provided.
  • FIG. 4 shows the time course of the surface temperature of the semiconductor wafer 3 irradiated with various laser beams.
  • the solid line indicates the surface temperature when the laser pulse LP of high frequency (800 kHz in the illustrated example) oscillated by the fiber laser device as the pulse laser device 2 according to the present embodiment is irradiated.
  • the dashed line indicates the surface temperature when irradiated with a high peak power (typically several 100 kW) and low frequency (typically between 2 kHz and several 10 kHz) laser pulses emitted by conventional pulsed laser equipment. show.
  • the dashed-dotted line indicates the surface temperature when irradiated with a low peak power (typically several kW) and low frequency laser light emitted by a conventional diode laser device. Note that the peak power is the value obtained by dividing the pulse energy by the pulse width.
  • a high peak power, low frequency laser pulse emitted by a conventional pulse oscillation laser device shown by a broken line is used for the purpose of repairing damage caused by dopant ion implantation by melting the surface of the semiconductor wafer 3.
  • the semiconductor wafer 3 is made of general silicon, the surface will be melted by heating it above its melting point (1,410° C.).
  • the surface temperature of the semiconductor wafer 3 instantaneously rises to over 1,500°C due to the high peak power laser pulses emitted by the conventional pulsed laser device shown by the broken line.
  • the surface of the formed semiconductor wafer 3 is melted and damage is repaired.
  • the conventional laser pulse has a low frequency, the surface temperature of the semiconductor wafer 3 drops rapidly immediately after the laser pulse is irradiated. For this reason, the interior or subsurface of the semiconductor wafer 3 into which the dopant is implanted is not sufficiently heated, and the dopant is not activated.
  • a low peak power and low frequency laser beam oscillated by a conventional diode laser device shown by a dashed line is used. Since this laser beam has a low peak power, it cannot heat the surface of the semiconductor wafer 3 above its melting point, but it continuously heats the inside or under the surface of the semiconductor wafer 3 to activate the implanted dopant. can. In this way, a pulsed laser device (dashed line) is generally used for melting on the surface of the semiconductor wafer 3, and a diode laser device (dotted chain line) is used for activation below the surface of the semiconductor wafer 3. Met. Since it is necessary to prepare different laser devices for annealing for different purposes, this has led to an increase in the size and cost of the laser annealing device.
  • one pulse laser device 2 melts the surface of the semiconductor wafer 3 and melts the surface of the semiconductor wafer 3. Activation at the bottom can be effectively achieved.
  • the pulsed laser device 2 according to the present embodiment performs a surface melting step (a period of "surface melting” shown in the figure) in which the surface of the semiconductor wafer 3 is heated to a temperature higher than the melting point and melted by a plurality of laser pulses LP.
  • the semiconductor wafer 3 is irradiated with laser pulses LP, and the temperature below the surface of the semiconductor wafer 3 is raised to a predetermined activation temperature or higher for at least a predetermined period of time using a plurality of laser pulses LP. , an activation step (the illustrated "activation" period) for activating the dopant added below the surface of the semiconductor wafer 3.
  • the surface temperature of the semiconductor wafer 3 rises above the melting point (1,410° C.) by a large number of laser pulses LP that are intermittently irradiated at a high frequency (800 kHz in the illustrated example). Therefore, the surface of the semiconductor wafer 3 is melted, and damage caused by dopant ion implantation or the like is repaired.
  • the individual laser pulses LP do not have sufficient power to heat the surface of the semiconductor wafer 3 above the melting point, but the semiconductor wafer 3 is heated by being irradiated with high frequency. As a result of accumulation, the surface temperature can be raised above the melting point.
  • the surface melting step starts when the surface temperature of the semiconductor wafer 3 rises above the melting point, and ends when the surface temperature of the semiconductor wafer 3 falls below the melting point.
  • the laser pulse LP is scanned in the Y direction (y direction) on the semiconductor wafer 3 by the galvano scanner 14 as a laser pulse scanning unit, but the laser pulse LP having a width in the Y direction is scanned on the semiconductor wafer 3
  • the time required to pass through a point is substantially equal to the time of the surface melting step. Strictly speaking, the time from when the laser pulse LP starts hitting a point on the semiconductor wafer 3 until the surface temperature reaches the melting point, and the time from when the laser pulse LP passes a point on the semiconductor wafer 3 until the surface temperature falls below the melting point. Due to time constraints, there may be a slight time difference.
  • the semiconductor wafer 3 is irradiated with the laser pulse LP continuously from the surface melting step, so that the temperature inside or under the surface of the semiconductor wafer 3 into which the dopant is implanted is increased to a predetermined activation temperature or higher. , the dopant is activated.
  • the activation temperature may vary depending on the type of dopant and the material of the semiconductor wafer 3 (silicon, silicon carbide, gallium nitride, etc.), but the most common method is to implant an acceptor (P-type dopant) such as boron into a silicon semiconductor wafer 3. In a typical case, the temperature is about 1,000°C.
  • the temperature of that region is maintained at or above the activation temperature for a predetermined period of time.
  • This predetermined time may also vary depending on the type and amount of dopant and the material of the semiconductor wafer 3, but is typically about 10 ⁇ s.
  • the interior or subsurface region of the semiconductor wafer 3 into which the dopants have been implanted is heated to 1000° C. for at least 10 ⁇ s.
  • a typical goal is to increase the temperature above this level.
  • the activation step starts when the temperature of the activation region under the surface of the semiconductor wafer 3 into which the dopant is implanted rises above the activation temperature, and ends when the temperature of the activation region falls below the activation temperature. do. Since FIG. 4, which shows the surface temperature of the semiconductor wafer 3, does not show the temperature of the activation region below the surface, the start timing and end timing of the activation step are shown as a guide. Typically, the activation step is shorter than the surface fusing step, as shown. Additionally, the start timing of the activation step is typically later than the start timing of the surface melting step. Furthermore, the end timing of the activation step is substantially equal to the end timing of the surface melting step.
  • the temperature of the activation region in the semiconductor wafer 3 involved in the activation step is less likely to drop than the temperature of the surface of the semiconductor wafer 3 involved in the surface melting step.
  • the timing of the end of the surface melting step (the surface temperature decreases below the melting point) is considered to be slightly later than the end timing of the surface melting step (the surface temperature decreases below the melting point).
  • the activation step may be made longer than 10 ⁇ s.
  • the activation step can be lengthened by slowing down the scanning speed of the laser pulse LP in the Y direction (y direction) by the galvano scanner 14 as a laser pulse scanning unit.
  • the same effect can be obtained by setting the oscillation frequency of the laser pulse LP by the pulse laser device 2 higher than 800 kHz.
  • the surface melting step will inevitably be lengthened, but the surface of the semiconductor wafer 3 may become overheated due to heat radiation from the surface of the semiconductor wafer 3 during the non-pulse period when the intermittent laser pulse LP is not irradiated. (In the example shown, the surface temperature is kept below 2,000°C.) In this way, according to the present embodiment, the surface melting step can be appropriately performed regardless of the length of the activation step.
  • one pulsed laser device 2 continues to irradiate the semiconductor wafer 3 with laser pulses LP through the successive surface melting steps and activation steps, thereby combining melting on the surface and activation below the surface. You can do it.
  • each device and each method described in the embodiments can be realized by hardware resources or software resources, or by cooperation of hardware resources and software resources.
  • hardware resources for example, a processor, ROM, RAM, and various integrated circuits can be used.
  • software resources for example, programs such as operating systems and applications can be used.
  • the present invention relates to a laser annealing device and the like.
  • Laser annealing device 2. Pulse laser device, 3. Semiconductor wafer, 4. Stage device, 11. Beam expander, 13. Beam shaping optical element, 14. Galvano scanner, 20. Optical fiber, 22. Laser light generation unit, LP laser pulse.

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Abstract

This laser annealing apparatus performs: a surface melting step for irradiating a semiconductor wafer with laser pulses LP oscillated by a pulse laser device and melting the surface of the semiconductor wafer by heating the surface thereof to a melting point or higher by means of a plurality of laser pulses (LP); and an activation step for irradiating the semiconductor wafer with the laser pulses (LP) consecutively from the surface melting step, and further heating the lower portion of the surface of the semiconductor wafer to a predetermined activation temperature or higher by means of the plurality of laser pulses (LP) for at least a predetermined time period, so that a dopant added to the lower portion of the surface of the semiconductor wafer is activated. In the activation step, a region up to 10 μm below the surface of the semiconductor wafer is heated to 1,000 °C or higher over at least 10 μs.

Description

レーザアニール装置、レーザアニール方法、レーザアニールプログラムLaser annealing equipment, laser annealing method, laser annealing program
　本発明は、レーザアニール装置等に関する。 The present invention relates to a laser annealing device and the like.
　特許文献１には、レーザ装置が発振するレーザ光を半導体ウエハに照射するレーザアニール技術が開示されている。極めて浅いpn接合の形成を目的とする本技術では、半導体ウエハを溶融させない強度のレーザ光を照射することで、半導体ウエハの表面直下に添加されたドーパントを活性化する。また、それに続く「低温急速熱アニール」によって、半導体ウエハの結晶の損傷が修復される。 Patent Document 1 discloses a laser annealing technique in which a semiconductor wafer is irradiated with laser light oscillated by a laser device. This technology, which aims to form extremely shallow p-n junctions, activates dopants added just below the surface of the semiconductor wafer by irradiating it with laser light strong enough not to melt the semiconductor wafer. Further, the subsequent "low temperature rapid thermal annealing" repairs damage to the crystals of the semiconductor wafer.
特表２００３－５２８４６２号公報Special Publication No. 2003-528462 特開２０１３－２５８２８８号公報JP2013-258288A
　レーザアニールでは、特許文献１と異なり、半導体ウエハの表面を溶融させることで、ドーパントのイオン注入による損傷を修復することも一般的である。このように、レーザアニールには、半導体ウエハの表面の溶融による損傷修復と、半導体ウエハ内に注入されたドーパントの活性化という、二つの異なる役割がある。特許文献２に開示されているように、表面における溶融および表面下における活性化を効果的に実現するためには、複数の異なる態様のレーザ光が必要となり、典型的には複数の異なるレーザ装置を用意する必要があった。 In laser annealing, unlike Patent Document 1, it is also common to repair damage caused by dopant ion implantation by melting the surface of the semiconductor wafer. Thus, laser annealing has two different roles: repairing damage by melting the surface of the semiconductor wafer and activating dopants implanted into the semiconductor wafer. As disclosed in Patent Document 2, in order to effectively achieve surface melting and subsurface activation, multiple different modes of laser light are required, and typically multiple different laser devices are required. It was necessary to prepare.
　本発明はこうした状況に鑑みてなされたものであり、一つのパルスレーザ装置によって半導体ウエハの表面における溶融および半導体ウエハの表面下における活性化を効果的に実現できるレーザアニール装置等を提供することを目的とする。 The present invention has been made in view of these circumstances, and it is an object of the present invention to provide a laser annealing device and the like that can effectively melt the surface of a semiconductor wafer and activate the subsurface of the semiconductor wafer using a single pulse laser device. purpose.
　上記課題を解決するために、本発明のある態様のレーザアニール装置は、パルスレーザ装置が発振するレーザパルスを半導体ウエハに照射し、複数のレーザパルスによって半導体ウエハの表面を融点以上に昇温して溶融させる表面溶融ステップと、表面溶融ステップから継続してレーザパルスを半導体ウエハに照射し、更に複数のレーザパルスによって半導体ウエハの表面下を少なくとも所定時間に亘って所定の活性化温度以上に昇温し、半導体ウエハの表面下に添加されたドーパントを活性化する活性化ステップと、を実行する。 In order to solve the above problems, a laser annealing apparatus according to an embodiment of the present invention irradiates a semiconductor wafer with laser pulses oscillated by a pulsed laser apparatus, and heats the surface of the semiconductor wafer above its melting point using a plurality of laser pulses. a surface melting step in which the semiconductor wafer is melted, and a laser pulse is continuously irradiated to the semiconductor wafer from the surface melting step, and the subsurface of the semiconductor wafer is raised to a predetermined activation temperature or higher for at least a predetermined time using a plurality of laser pulses. heating and activating dopants added below the surface of the semiconductor wafer.
　この態様では、連続する表面溶融ステップおよび活性化ステップを通じて、一つのパルスレーザ装置がレーザパルスを半導体ウエハに照射し続けることで、表面における溶融および表面下における活性化が併せて行われる。表面溶融ステップにおいて溶融した半導体ウエハの表面には、活性化ステップにおいてもレーザパルスが間欠的に照射され続けるが、レーザパルスが照射されない非パルス期間における表面からの放熱等によって、活性化ステップの間に半導体ウエハの表面が過熱状態となることが防止される。なお、表面溶融ステップおよび活性化ステップは時間的に重複していてもよい。 In this embodiment, one pulsed laser device continues to irradiate the semiconductor wafer with laser pulses through successive surface melting steps and activation steps, thereby performing both surface melting and subsurface activation. The surface of the semiconductor wafer melted in the surface melting step continues to be intermittently irradiated with laser pulses even in the activation step, but due to heat radiation from the surface during the non-pulse period when the laser pulse is not irradiated, the surface of the semiconductor wafer melted during the activation step. This prevents the surface of the semiconductor wafer from becoming overheated. Note that the surface melting step and the activation step may overlap in time.
　本発明の別の態様は、レーザアニール方法である。この方法は、パルスレーザ装置が発振するレーザパルスを半導体ウエハに照射し、複数のレーザパルスによって半導体ウエハの表面を融点以上に昇温して溶融させる表面溶融ステップと、表面溶融ステップから継続してレーザパルスを半導体ウエハに照射し、更に複数のレーザパルスによって半導体ウエハの表面下を少なくとも所定時間に亘って所定の活性化温度以上に昇温し、半導体ウエハの表面下に添加されたドーパントを活性化する活性化ステップと、からなる。 Another aspect of the present invention is a laser annealing method. This method consists of a surface melting step in which the semiconductor wafer is irradiated with laser pulses emitted by a pulsed laser device, and the surface of the semiconductor wafer is heated to a temperature higher than the melting point by multiple laser pulses and melted, and the surface melting step is continued. The semiconductor wafer is irradiated with a laser pulse, and the temperature below the surface of the semiconductor wafer is raised to a predetermined activation temperature or higher for at least a predetermined period of time using multiple laser pulses, thereby activating the dopants added below the surface of the semiconductor wafer. an activation step of activating the method.
　なお、以上の構成要素の任意の組合せや、これらの表現を方法、装置、システム、記録媒体、コンピュータプログラム等に変換したものも、本発明に包含される。 It should be noted that the present invention also encompasses any combination of the above components and the conversion of these expressions into methods, devices, systems, recording media, computer programs, etc.
　本発明によれば、一つのパルスレーザ装置によって半導体ウエハの表面における溶融および半導体ウエハの表面下における活性化を効果的に実現できる。 According to the present invention, melting on the surface of a semiconductor wafer and activation below the surface of the semiconductor wafer can be effectively achieved with one pulse laser device.
レーザアニール装置の構成を模式的に示す斜視図である。FIG. 1 is a perspective view schematically showing the configuration of a laser annealing device. ファイバレーザ装置の要部である光ファイバの構成と、光ファイバにおけるレーザパルスの発生および増幅の原理を模式的に示す。The configuration of an optical fiber, which is a main part of a fiber laser device, and the principles of laser pulse generation and amplification in the optical fiber are schematically shown. ファイバレーザ装置としてのパルスレーザ装置の構成を模式的に示す。The configuration of a pulse laser device as a fiber laser device is schematically shown. 各種のレーザ光が照射された半導体ウエハの表面温度の時間推移を示す。3 shows the time course of the surface temperature of a semiconductor wafer irradiated with various laser beams.
　以下では、図面を参照しながら、本発明を実施するための形態（以下では実施形態ともいう）について詳細に説明する。説明および／または図面においては、同一または同等の構成要素、部材、処理等に同一の符号を付して重複する説明を省略する。図示される各部の縮尺や形状は、説明の簡易化のために便宜的に設定されており、特に言及がない限り限定的に解釈されるものではない。実施形態は例示であり、本発明の範囲を何ら限定するものではない。実施形態に記載される全ての特徴やそれらの組合せは、必ずしも本発明の本質的なものであるとは限らない。 Hereinafter, modes for carrying out the present invention (hereinafter also referred to as embodiments) will be described in detail with reference to the drawings. In the description and/or drawings, the same or equivalent components, members, processes, etc. are denoted by the same reference numerals, and redundant description will be omitted. The scales and shapes of the parts shown in the drawings are set for convenience to simplify the explanation, and should not be interpreted in a limited manner unless otherwise stated. The embodiments are illustrative and do not limit the scope of the present invention. Not all features or combinations thereof described in the embodiments are necessarily essential to the present invention.
　図１は、本発明の実施形態に係るレーザアニール装置１の構成を模式的に示す斜視図である。レーザアニール装置１は、パルスレーザ装置２が発振するレーザパルスを半導体ウエハ３に照射してアニール処理（加熱処理）を施す装置である。 FIG. 1 is a perspective view schematically showing the configuration of a laser annealing apparatus 1 according to an embodiment of the present invention. The laser annealing device 1 is a device that performs an annealing process (heating process) by irradiating the semiconductor wafer 3 with laser pulses generated by a pulsed laser device 2 .
　ウエハテーブル３１に固定的に載置された半導体ウエハ３は、後述するステージ装置４によってウエハテーブル３１と一体的に図示のｘ方向に駆動可能である。また、パルスレーザ装置２によって発振されたレーザパルス（レーザ光）は、後述するガルバノスキャナ１４によってｘ方向と直交するｙ方向に走査（スキャン）可能である。ガルバノスキャナ１４によってｙ方向に走査されたレーザパルス（レーザ光）は、後述するミラー１６によって反射されてｘ方向およびｙ方向と直交するｚ方向に半導体ウエハ３に入射する。 The semiconductor wafer 3 fixedly mounted on the wafer table 31 can be driven integrally with the wafer table 31 in the illustrated x direction by a stage device 4, which will be described later. Further, the laser pulse (laser light) oscillated by the pulse laser device 2 can be scanned in the y direction orthogonal to the x direction by a galvano scanner 14, which will be described later. Laser pulses (laser light) scanned in the y direction by the galvano scanner 14 are reflected by a mirror 16, which will be described later, and are incident on the semiconductor wafer 3 in the z direction orthogonal to the x and y directions.
　以下では、互いに直交するＸＹＺの各軸を座標軸とする三次元直交座標系に基づいて、レーザアニール装置１の構成および／または作用に関する方向を記述する。半導体ウエハ３の駆動方向であるｘ方向はＸ軸方向（Ｘ方向）と平行であり、レーザパルス（レーザ光）の走査方向であるｙ方向はＹ軸方向（Ｙ方向）と平行であり、半導体ウエハ３に対するレーザパルス（レーザ光）の入射方向であるｚ方向はＺ軸方向（Ｚ方向）と平行である。以下では便宜的に、ｘ方向およびＸ方向を縦方向ともいい、ｙ方向およびＹ方向を横方向ともいい、ｚ方向およびＺ方向を高さ方向ともいう。 Hereinafter, directions regarding the configuration and/or operation of the laser annealing apparatus 1 will be described based on a three-dimensional orthogonal coordinate system whose coordinate axes are XYZ axes that are perpendicular to each other. The x direction, which is the driving direction of the semiconductor wafer 3, is parallel to the X-axis direction (X direction), and the y direction, which is the scanning direction of the laser pulse (laser light), is parallel to the Y-axis direction (Y direction). The z direction, which is the direction of incidence of the laser pulse (laser light) on the wafer 3, is parallel to the Z-axis direction (Z direction). Hereinafter, for convenience, the x direction and the X direction will also be referred to as the vertical direction, the y direction and the Y direction will also be referred to as the horizontal direction, and the z direction and the Z direction will also be referred to as the height direction.
　パルスレーザ装置２は、100kHz以上の周波数でレーザパルスを発振するレーザ装置である。本実施形態に係るレーザアニール装置１の後述する作用や効果を十分に得る上で、パルスレーザ装置２によって発振されるレーザパルスの周波数は、例えば100kHzと10MHzの間であり、500kHzと5MHzの間であるのが好ましく、700kHzと3MHzの間であるのが更に好ましい。本実施形態では、パルスレーザ装置２によって発振されるレーザパルスの周波数が800kHzである例について説明する。 The pulse laser device 2 is a laser device that oscillates laser pulses at a frequency of 100kHz or higher. In order to fully obtain the functions and effects described below of the laser annealing device 1 according to the present embodiment, the frequency of the laser pulse oscillated by the pulsed laser device 2 is, for example, between 100kHz and 10MHz, and between 500kHz and 5MHz. , more preferably between 700kHz and 3MHz. In this embodiment, an example in which the frequency of the laser pulse oscillated by the pulse laser device 2 is 800 kHz will be described.
　本実施形態に係るパルスレーザ装置２は、例えば、光ファイバによってレーザパルスを発振するファイバレーザ装置によって構成される。図２は、ファイバレーザ装置の要部である光ファイバ２０の構成と、光ファイバ２０におけるレーザパルスＬＰの発生および増幅の原理を模式的に示す。光ファイバ２０は、中央部のコア２０１と、当該コア２０１の周囲に設けられる第１クラッド２０２と、当該第１クラッド２０２の周囲に設けられる第２クラッド２０３を備える。コア２０１の屈折率は第１クラッド２０２の屈折率より高く、第１クラッド２０２の屈折率は第２クラッド２０３の屈折率より高い。つまり、光ファイバ２０の屈折率は、中央部（コア２０１）に近いほど高く、周縁部（第２クラッド２０３）に近いほど低い。 The pulse laser device 2 according to the present embodiment is configured by, for example, a fiber laser device that oscillates laser pulses using an optical fiber. FIG. 2 schematically shows the configuration of an optical fiber 20, which is a main part of the fiber laser device, and the principle of generation and amplification of laser pulses LP in the optical fiber 20. The optical fiber 20 includes a core 201 in the center, a first clad 202 provided around the core 201, and a second clad 203 provided around the first clad 202. The refractive index of the core 201 is higher than the refractive index of the first cladding 202, and the refractive index of the first cladding 202 is higher than the refractive index of the second cladding 203. That is, the refractive index of the optical fiber 20 is higher as it is closer to the center (core 201) and lower as it is closer to the periphery (second cladding 203).
　光ファイバ２０の一端（例えば図２における左端）からは、レーザダイオード等の発光素子によって生成された励起光ＥＬが入射する。この励起光ＥＬは、第１クラッド２０２と第２クラッド２０３の境界面で全反射しながら、コア２０１および第１クラッド２０２の内部を伝播する。励起光ＥＬはコア２０１を通過する度に、コア２０１に添加されたYb等の希土類元素等を励起し、レーザパルスＬＰ（レーザ光）の元となる誘導放出光を生成させる。コア２０１で生成された誘導放出光は、コア２０１と第１クラッド２０２の境界面で全反射しながら、コア２０１の内部を伝播する。後述するように、コア２０１の両端部にはFBG（Fiber Bragg Grating）等の全反射鏡や出力鏡等の鏡が形成されており、これらの鏡の間で繰り返し反射される誘導放出光がコア２０１の内部を往復しながら増幅されることでレーザパルスＬＰ（レーザ光）が形成される。このレーザパルスＬＰは、コア２０１の一端部（例えば図２における右端部）に形成された出力鏡から光ファイバ２０外に出力される。 Excitation light EL generated by a light emitting element such as a laser diode enters from one end of the optical fiber 20 (for example, the left end in FIG. 2). This excitation light EL propagates inside the core 201 and the first cladding 202 while being totally reflected at the interface between the first cladding 202 and the second cladding 203. Each time the excitation light EL passes through the core 201, it excites a rare earth element such as Yb added to the core 201, and generates stimulated emission light that becomes the source of the laser pulse LP (laser light). The stimulated emission light generated in the core 201 propagates inside the core 201 while being totally reflected at the interface between the core 201 and the first cladding 202 . As described later, mirrors such as total reflection mirrors such as FBG (Fiber Bragg Grating) and output mirrors are formed at both ends of the core 201, and the stimulated emission light that is repeatedly reflected between these mirrors is reflected back to the core. A laser pulse LP (laser light) is formed by being amplified while reciprocating inside the 201. This laser pulse LP is output to the outside of the optical fiber 20 from an output mirror formed at one end of the core 201 (for example, the right end in FIG. 2).
　図３は、図２のような光ファイバ２０を備えるファイバレーザ装置としてのパルスレーザ装置２の構成を模式的に示す。パルスレーザ装置２は、励起光供給部２１と、レーザ光生成部２２と、レーザ光供給部２３を備える。励起光供給部２１は、励起光ＥＬの元となる光を発する一または複数のレーザダイオード等の発光素子２１１と、発光素子２１１が複数設けられる場合にそれぞれの光を結合して励起光ＥＬを形成する光結合部２１２を備える。励起光供給部２１は、発光素子２１１が発した光に基づく励起光ＥＬをレーザ光生成部２２に供給する。 FIG. 3 schematically shows the configuration of a pulse laser device 2 as a fiber laser device including an optical fiber 20 as shown in FIG. The pulse laser device 2 includes an excitation light supply section 21, a laser light generation section 22, and a laser light supply section 23. The excitation light supply unit 21 includes a light emitting element 211 such as one or more laser diodes that emits light that is the source of the excitation light EL, and when a plurality of light emitting elements 211 are provided, combines the respective lights to generate the excitation light EL. It includes an optical coupling section 212 to be formed. The excitation light supply section 21 supplies excitation light EL based on the light emitted by the light emitting element 211 to the laser light generation section 22 .
　レーザ光生成部２２は、入力端（図３における左端）から励起光ＥＬが供給される前述の光ファイバ２０と、その両端部に形成される入力鏡２２１および出力鏡２２２を備える。入力鏡２２１および出力鏡２２２は、例えば、いずれもFBGによってコア２０１の両端部に形成される。入力側（励起光供給部２１側）に設けられる入力鏡２２１の反射率は、出力側（レーザ光供給部２３側）に設けられる出力鏡２２２の反射率より高くするのが好ましい。特に、入力鏡２２１は、レーザパルスＬＰ（レーザ光）の元となるコア２０１の内部の誘導放出光を、出力側に全反射する全反射鏡として構成されるのが好ましい。出力鏡２２２は、コア２０１の内部の誘導放出光の一部を入力側に反射し、残りをレーザ光供給部２３に対して出力する。 The laser light generation unit 22 includes the aforementioned optical fiber 20 to which the excitation light EL is supplied from the input end (left end in FIG. 3), and an input mirror 221 and an output mirror 222 formed at both ends thereof. The input mirror 221 and the output mirror 222 are both formed by FBG at both ends of the core 201, for example. It is preferable that the reflectance of the input mirror 221 provided on the input side (excitation light supply section 21 side) is higher than the reflectance of the output mirror 222 provided on the output side (laser light supply section 23 side). In particular, the input mirror 221 is preferably configured as a total reflection mirror that totally reflects the stimulated emission light inside the core 201, which is the source of the laser pulse LP (laser light), toward the output side. The output mirror 222 reflects a part of the stimulated emission light inside the core 201 to the input side, and outputs the rest to the laser light supply section 23 .
　レーザ光供給部２３は、レーザ光生成部２２が生成したレーザパルスＬＰ（レーザ光）を、パルスレーザ装置２の出力点ＯＰまで導く光ファイバ２３１を備える。なお、レーザ光生成部２２の出力点を、パルスレーザ装置２の出力点ＯＰとしてもよく、その場合はレーザ光供給部２３を設ける必要はない。 The laser light supply section 23 includes an optical fiber 231 that guides the laser pulse LP (laser light) generated by the laser light generation section 22 to the output point OP of the pulse laser device 2. Note that the output point of the laser beam generation section 22 may be the output point OP of the pulsed laser device 2, and in that case, it is not necessary to provide the laser beam supply section 23.
　図１において、レーザパルスＬＰは、パルスレーザ装置２の出力点ＯＰからＸ方向に出射される。このレーザパルスＬＰを照射対象の半導体ウエハ３まで導くレーザアニール装置１は、ビームエキスパンダ１１と、ミラー１２と、ビーム整形光学素子１３と、ガルバノスキャナ１４と、fθレンズ１５と、ミラー１６を備える。 In FIG. 1, the laser pulse LP is emitted from the output point OP of the pulse laser device 2 in the X direction. A laser annealing device 1 that guides this laser pulse LP to a semiconductor wafer 3 to be irradiated includes a beam expander 11, a mirror 12, a beam shaping optical element 13, a galvano scanner 14, an fθ lens 15, and a mirror 16. .
　ビームエキスパンダ１１は、パルスレーザ装置２の出力点ＯＰから出射されたレーザパルスＬＰ（レーザ光）を所定のサイズ（径）に調整する。例えば、パルスレーザ装置２の出力点ＯＰから出射されたレーザパルスＬＰ（レーザ光）の断面が径D0の略円形である場合、ビームエキスパンダ１１は当該レーザパルスＬＰ（レーザ光）の断面を所定の径D1の略円形に変換（典型的には拡大）する。ビームエキスパンダ１１は、複数のレンズ１１１、１１２、１１３によって構成される。典型的には、レンズ１１１は凸レンズであり、レンズ１１２は凹レンズであり、レンズ１１３は凸レンズである。但し、ビームエキスパンダ１１を構成するレンズその他の光学素子の数や種類は、レーザパルスＬＰのサイズを調整するという所期の作用および／または効果が得られる限り任意である。例えば、ビームエキスパンダ１１は、任意の順に配置される二つ以上の凸レンズと一つ以上の凹レンズによって構成されてもよいし、三つ以上の凸レンズのみによって構成されてもよい。 The beam expander 11 adjusts the laser pulse LP (laser light) emitted from the output point OP of the pulse laser device 2 to a predetermined size (diameter). For example, when the cross section of the laser pulse LP (laser light) emitted from the output point OP of the pulse laser device 2 is approximately circular with a diameter D0, the beam expander 11 adjusts the cross section of the laser pulse LP (laser light) to a predetermined shape. Convert (typically enlarge) into a substantially circular shape with diameter D1. The beam expander 11 is composed of a plurality of lenses 111, 112, and 113. Typically, lens 111 is a convex lens, lens 112 is a concave lens, and lens 113 is a convex lens. However, the number and type of lenses and other optical elements constituting the beam expander 11 are arbitrary as long as the desired function and/or effect of adjusting the size of the laser pulse LP can be obtained. For example, the beam expander 11 may be composed of two or more convex lenses and one or more concave lenses arranged in any order, or may be composed only of three or more convex lenses.
　ミラー１２は、ビームエキスパンダ１１によってサイズが調整されたレーザパルスＬＰを反射し、その進行方向をＸ方向からＹ方向に変える。 The mirror 12 reflects the laser pulse LP whose size has been adjusted by the beam expander 11, and changes its traveling direction from the X direction to the Y direction.
　ビーム整形光学素子１３は、ビームエキスパンダ１１によってサイズが調整されたレーザパルスＬＰを整形して、その形状および／または強度分布を調整する。例えば、ビームエキスパンダ１１によってサイズが調整されたレーザパルスＬＰの断面は、略円形でガウス分布または正規分布に従う強度分布を有するが、ビーム整形光学素子１３によって略矩形で強度分布が略均一に整形される。このようなビーム整形光学素子１３は、例えば回折光学素子（DOE: Diffractive Optical Element）によって構成される。 The beam shaping optical element 13 shapes the laser pulse LP whose size has been adjusted by the beam expander 11, and adjusts its shape and/or intensity distribution. For example, the cross section of the laser pulse LP whose size has been adjusted by the beam expander 11 is approximately circular and has an intensity distribution that follows a Gaussian distribution or a normal distribution, but is shaped by the beam shaping optical element 13 to be approximately rectangular and have an approximately uniform intensity distribution. be done. Such a beam shaping optical element 13 is constituted by, for example, a diffractive optical element (DOE).
　ガルバノスキャナ１４は、ビーム整形光学素子１３によって整形されたレーザパルスＬＰをｙ方向（Ｙ方向）に走査するレーザパルス走査部である。ガルバノスキャナ１４は、レーザパルスＬＰを反射可能なガルバノミラー１４１と、当該ガルバノミラー１４１をＺ軸周りに回転駆動するモータ１４２を備える。モータ１４２によってガルバノミラー１４１のＺ軸周りの回転位置または回転角度が調整されることで、ガルバノミラー１４１に入射するレーザパルスＬＰが任意のｙ方向位置に反射される。 The galvano scanner 14 is a laser pulse scanning unit that scans the laser pulse LP shaped by the beam shaping optical element 13 in the y direction (Y direction). The galvano scanner 14 includes a galvano mirror 141 that can reflect the laser pulse LP, and a motor 142 that rotates the galvano mirror 141 around the Z axis. The motor 142 adjusts the rotational position or rotational angle of the galvano mirror 141 around the Z axis, so that the laser pulse LP incident on the galvano mirror 141 is reflected to an arbitrary position in the y direction.
　なお、レーザパルスＬＰをｙ方向に走査するレーザパルス走査部はガルバノスキャナ１４に限らず、回転駆動可能なポリゴンミラーを備えるポリゴンミラースキャナや、MEMS（Micro Electro Mechanical Systems）ミラー等によって構成されてもよい。また、ガルバノスキャナ１４等のレーザパルス走査部によるレーザパルスＬＰの走査方向もｙ方向（Y方向）に限らず、ｘ方向（X方向）等のｙ方向（Y方向）に交差する方向でもよいし、ｘ方向（X方向）およびｙ方向（Y方向）の二方向でもよい。後者の場合のように、ガルバノスキャナ１４等のレーザパルス走査部が、ｘｙ平面内（ＸＹ平面内）すなわち半導体ウエハ３面内でレーザパルスＬＰを走査できる場合、半導体ウエハ３およびウエハテーブル３１をｘ方向（Ｘ方向）等に駆動するステージ装置４を設けなくてもよい。 Note that the laser pulse scanning unit that scans the laser pulse LP in the y direction is not limited to the galvano scanner 14, but may also be configured by a polygon mirror scanner equipped with a polygon mirror that can be rotated, a MEMS (Micro Electro Mechanical Systems) mirror, etc. good. Further, the scanning direction of the laser pulse LP by the laser pulse scanning unit such as the galvano scanner 14 is not limited to the y direction (Y direction), but may be a direction intersecting the y direction (Y direction) such as the x direction (X direction). , the x direction (X direction) and the y direction (Y direction) may be used. As in the latter case, when the laser pulse scanning unit such as the galvano scanner 14 can scan the laser pulse LP within the xy plane (XY plane), that is, within the plane of the semiconductor wafer 3, the semiconductor wafer 3 and the wafer table 31 are It is not necessary to provide a stage device 4 that is driven in a direction (X direction) or the like.
　fθレンズ１５は、ガルバノスキャナ１４によってｙ方向（Ｙ方向）に走査されたレーザパルスＬＰをアニール対象の半導体ウエハ３に集光する。fθレンズ１５と半導体ウエハ３の間に設けられるミラー１６は、fθレンズ１５からのＸ方向のレーザパルスＬＰを反射してＺ方向（ｚ方向）に半導体ウエハ３に照射する。このようにfθレンズ１５およびミラー１６によって半導体ウエハ３に集光されるレーザパルスＬＰは、ガルバノスキャナ１４によるｙ方向の走査によって半導体ウエハ３面内をＹ方向に移動する。半導体ウエハ３に集光されるレーザパルスＬＰのサイズは任意に設計できるが、例えば0.10mm四方と0.15mm四方の間とするのが好ましく、0.12mm四方と0.13mm四方とするのが更に好ましい。また、半導体ウエハ３面におけるレーザパルスＬＰのＹ方向の走査速度（および／または、ステージ装置４による半導体ウエハ３のＸ方向の駆動速度）も任意に設計できるが、例えば100 cm/sと500 cm/sの間とするのが好ましく、250 cm/sと350 cm/sの間とするのが更に好ましい。 The fθ lens 15 focuses the laser pulse LP scanned in the y direction (Y direction) by the galvano scanner 14 onto the semiconductor wafer 3 to be annealed. A mirror 16 provided between the fθ lens 15 and the semiconductor wafer 3 reflects the laser pulse LP in the X direction from the fθ lens 15 and irradiates the semiconductor wafer 3 in the Z direction (z direction). The laser pulse LP thus focused on the semiconductor wafer 3 by the fθ lens 15 and the mirror 16 moves in the Y direction within the plane of the semiconductor wafer 3 by scanning in the Y direction by the galvano scanner 14. Although the size of the laser pulse LP focused on the semiconductor wafer 3 can be arbitrarily designed, it is preferably between 0.10 mm square and 0.15 mm square, and more preferably between 0.12 mm square and 0.13 mm square. Furthermore, the scanning speed of the laser pulse LP in the Y direction on the semiconductor wafer 3 surface (and/or the driving speed of the semiconductor wafer 3 in the X direction by the stage device 4) can be arbitrarily designed; for example, 100 cm/s and 500 cm. It is preferably between 250 cm/s and 350 cm/s, more preferably between 250 cm/s and 350 cm/s.
　また、ステージ装置４が半導体ウエハ３およびウエハテーブル３１をｘ方向（Ｘ方向）に駆動することで、レーザパルスＬＰは半導体ウエハ３面内をＸ方向に相対移動する。このように、ガルバノスキャナ１４によるレーザパルスＬＰのｙ方向の走査と、ステージ装置４による半導体ウエハ３のｘ方向の駆動を組み合わせることで、レーザパルスＬＰをｘｙ平面内（ＸＹ平面内）すなわち半導体ウエハ３面内で走査できる。なお、ステージ装置４による半導体ウエハ３の駆動方向はｘ方向（Ｘ方向）に限らず、ｙ方向（Ｙ方向）等のｘ方向（Ｘ方向）に交差する方向でもよいし、ｘ方向（X方向）およびｙ方向（Y方向）の二方向でもよい。後者の場合のように、ステージ装置４がｘｙ平面内（ＸＹ平面内）で半導体ウエハ３をレーザパルスＬＰに対して相対駆動できる場合、レーザパルスＬＰをｙ方向（Ｙ方向）等に走査するガルバノスキャナ１４等のレーザパルス走査部を設けなくてもよい。 Further, by the stage device 4 driving the semiconductor wafer 3 and the wafer table 31 in the x direction (X direction), the laser pulse LP moves relatively within the surface of the semiconductor wafer 3 in the X direction. In this way, by combining the scanning of the laser pulse LP in the y direction by the galvano scanner 14 and the driving of the semiconductor wafer 3 in the x direction by the stage device 4, the laser pulse LP can be moved within the xy plane (in the XY plane), that is, the semiconductor wafer 3. Can scan in 3 planes. Note that the driving direction of the semiconductor wafer 3 by the stage device 4 is not limited to the x direction (X direction), but may also be a direction intersecting the x direction (X direction) such as the y direction (Y direction), or ) and the y direction (Y direction). As in the latter case, when the stage device 4 can drive the semiconductor wafer 3 relative to the laser pulse LP within the xy plane (XY plane), a galvanometer that scans the laser pulse LP in the y direction (Y direction) etc. A laser pulse scanning unit such as the scanner 14 may not be provided.
　図４は、各種のレーザ光が照射された半導体ウエハ３の表面温度の時間推移を示す。実線は、本実施形態に係るパルスレーザ装置２としてのファイバレーザ装置が発振する高周波数（図示の例では800kHz）のレーザパルスＬＰが照射された際の表面温度を示す。破線は、従来のパルス発振レーザ装置が発振する高ピークパワー（典型的には数100kW）かつ低周波数（典型的には2kHzと数10kHzの間）のレーザパルスが照射された際の表面温度を示す。一点鎖線は、従来のダイオードレーザ装置が発振する低ピークパワー（典型的には数kW）かつ低周波数のレーザ光が照射された際の表面温度を示す。なお、ピークパワーとは、パルスエネルギーをパルス幅で除した値である。 FIG. 4 shows the time course of the surface temperature of the semiconductor wafer 3 irradiated with various laser beams. The solid line indicates the surface temperature when the laser pulse LP of high frequency (800 kHz in the illustrated example) oscillated by the fiber laser device as the pulse laser device 2 according to the present embodiment is irradiated. The dashed line indicates the surface temperature when irradiated with a high peak power (typically several 100 kW) and low frequency (typically between 2 kHz and several 10 kHz) laser pulses emitted by conventional pulsed laser equipment. show. The dashed-dotted line indicates the surface temperature when irradiated with a low peak power (typically several kW) and low frequency laser light emitted by a conventional diode laser device. Note that the peak power is the value obtained by dividing the pulse energy by the pulse width.
　破線で示される従来のパルス発振レーザ装置が発振する高ピークパワーかつ低周波数のレーザパルスは、半導体ウエハ３の表面を溶融させることで、ドーパントのイオン注入による損傷を修復する目的で使用される。半導体ウエハ３が一般的なシリコンによって形成される場合、その融点（1,410℃）以上に加熱することで表面が溶融する。図示の例では、破線で示される従来のパルス発振レーザ装置が発振する高ピークパワーのレーザパルスによって、半導体ウエハ３の表面温度が瞬間的に1,500℃以上に上がるため、融点が1,410℃のシリコンで形成される半導体ウエハ３の表面が溶融して損傷が修復される。しかし、従来のレーザパルスは低周波数であるため、半導体ウエハ３の表面温度はレーザパルス照射直後に急激に下がる。このため、ドーパントが注入された半導体ウエハ３の内部または表面下は十分に加熱されず、ドーパントは活性化されない。 A high peak power, low frequency laser pulse emitted by a conventional pulse oscillation laser device shown by a broken line is used for the purpose of repairing damage caused by dopant ion implantation by melting the surface of the semiconductor wafer 3. If the semiconductor wafer 3 is made of general silicon, the surface will be melted by heating it above its melting point (1,410° C.). In the illustrated example, the surface temperature of the semiconductor wafer 3 instantaneously rises to over 1,500°C due to the high peak power laser pulses emitted by the conventional pulsed laser device shown by the broken line. The surface of the formed semiconductor wafer 3 is melted and damage is repaired. However, since the conventional laser pulse has a low frequency, the surface temperature of the semiconductor wafer 3 drops rapidly immediately after the laser pulse is irradiated. For this reason, the interior or subsurface of the semiconductor wafer 3 into which the dopant is implanted is not sufficiently heated, and the dopant is not activated.
　そこで、半導体ウエハ３内に注入されたドーパントを活性化する目的で、一点鎖線で示される従来のダイオードレーザ装置が発振する低ピークパワーかつ低周波数のレーザ光が使用される。このレーザ光は低ピークパワーであるため、半導体ウエハ３の表面を融点以上に加熱することはできないが、半導体ウエハ３の内部または表面下を持続的に加熱して、注入されたドーパントを活性化できる。このように、半導体ウエハ３の表面における溶融にはパルス発振レーザ装置（破線）が使用され、半導体ウエハ３の表面下における活性化にはダイオードレーザ装置（一点鎖線）が使用されるのが一般的であった。異なる目的のアニールのために異なるレーザ装置を用意する必要があるため、レーザアニール装置の大型化や高コスト化に繋がっていた。 Therefore, for the purpose of activating the dopant implanted into the semiconductor wafer 3, a low peak power and low frequency laser beam oscillated by a conventional diode laser device shown by a dashed line is used. Since this laser beam has a low peak power, it cannot heat the surface of the semiconductor wafer 3 above its melting point, but it continuously heats the inside or under the surface of the semiconductor wafer 3 to activate the implanted dopant. can. In this way, a pulsed laser device (dashed line) is generally used for melting on the surface of the semiconductor wafer 3, and a diode laser device (dotted chain line) is used for activation below the surface of the semiconductor wafer 3. Met. Since it is necessary to prepare different laser devices for annealing for different purposes, this has led to an increase in the size and cost of the laser annealing device.
　これに対して、実線で示される本実施形態に係る高周波数のレーザパルスＬＰによれば、一つのパルスレーザ装置２（ファイバレーザ装置等）によって半導体ウエハ３の表面における溶融および半導体ウエハ３の表面下における活性化を効果的に実現できる。具体的には、本実施形態に係るパルスレーザ装置２は、複数のレーザパルスＬＰによって半導体ウエハ３の表面を融点以上に昇温して溶融させる表面溶融ステップ（図示の「表面溶融」の期間）と、表面溶融ステップから継続してレーザパルスＬＰを半導体ウエハ３に照射し、更に複数のレーザパルスＬＰによって半導体ウエハ３の表面下を少なくとも所定時間に亘って所定の活性化温度以上に昇温し、半導体ウエハ３の表面下に添加されたドーパントを活性化する活性化ステップ（図示の「活性化」の期間）と、を実行する。 On the other hand, according to the high frequency laser pulse LP according to the present embodiment shown by the solid line, one pulse laser device 2 (fiber laser device etc.) melts the surface of the semiconductor wafer 3 and melts the surface of the semiconductor wafer 3. Activation at the bottom can be effectively achieved. Specifically, the pulsed laser device 2 according to the present embodiment performs a surface melting step (a period of "surface melting" shown in the figure) in which the surface of the semiconductor wafer 3 is heated to a temperature higher than the melting point and melted by a plurality of laser pulses LP. Continuing from the surface melting step, the semiconductor wafer 3 is irradiated with laser pulses LP, and the temperature below the surface of the semiconductor wafer 3 is raised to a predetermined activation temperature or higher for at least a predetermined period of time using a plurality of laser pulses LP. , an activation step (the illustrated "activation" period) for activating the dopant added below the surface of the semiconductor wafer 3.
　表面溶融ステップでは、高周波数（図示の例では800kHz）で間欠的に照射される多数のレーザパルスＬＰによって、半導体ウエハ３の表面温度が融点（1,410℃）以上に上がる。このため、半導体ウエハ３の表面が溶融して、ドーパントのイオン注入等による損傷が修復される。なお、図示されるように、個々のレーザパルスＬＰは、半導体ウエハ３の表面を融点以上に加熱するための十分なパワーを持たないが、高周波数で照射されることで半導体ウエハ３に熱が蓄積される結果、その表面温度を融点以上に上げられる。表面溶融ステップは、半導体ウエハ３の表面温度が融点以上に上がった時に開始し、半導体ウエハ３の表面温度が融点未満に下がった時に終了する。 In the surface melting step, the surface temperature of the semiconductor wafer 3 rises above the melting point (1,410° C.) by a large number of laser pulses LP that are intermittently irradiated at a high frequency (800 kHz in the illustrated example). Therefore, the surface of the semiconductor wafer 3 is melted, and damage caused by dopant ion implantation or the like is repaired. Note that, as shown in the figure, the individual laser pulses LP do not have sufficient power to heat the surface of the semiconductor wafer 3 above the melting point, but the semiconductor wafer 3 is heated by being irradiated with high frequency. As a result of accumulation, the surface temperature can be raised above the melting point. The surface melting step starts when the surface temperature of the semiconductor wafer 3 rises above the melting point, and ends when the surface temperature of the semiconductor wafer 3 falls below the melting point.
　前述のように、レーザパルスＬＰはレーザパルス走査部としてのガルバノスキャナ１４によって半導体ウエハ３上をＹ方向（ｙ方向）に走査されるが、Ｙ方向に幅を持つレーザパルスＬＰが半導体ウエハ３上の一点を通過するのに要する時間は表面溶融ステップの時間と実質的に等しい。厳密には、レーザパルスＬＰが半導体ウエハ３上の一点に当たり始めてから表面温度が融点に達するまでの時間と、レーザパルスＬＰが半導体ウエハ３上の一点を通過した後に表面温度が融点を下回るまでの時間があるため、僅かな時間差が存在しうる。 As mentioned above, the laser pulse LP is scanned in the Y direction (y direction) on the semiconductor wafer 3 by the galvano scanner 14 as a laser pulse scanning unit, but the laser pulse LP having a width in the Y direction is scanned on the semiconductor wafer 3 The time required to pass through a point is substantially equal to the time of the surface melting step. Strictly speaking, the time from when the laser pulse LP starts hitting a point on the semiconductor wafer 3 until the surface temperature reaches the melting point, and the time from when the laser pulse LP passes a point on the semiconductor wafer 3 until the surface temperature falls below the melting point. Due to time constraints, there may be a slight time difference.
　活性化ステップでは、表面溶融ステップから継続してレーザパルスＬＰが半導体ウエハ３に照射されることで、ドーパントが注入された半導体ウエハ３の内部または表面下が所定の活性化温度以上に昇温し、ドーパントが活性化される。活性化温度は、ドーパントの種類や半導体ウエハ３の材料（シリコン、炭化ケイ素、窒化ガリウム等）によって異なりうるが、最も一般的なシリコンの半導体ウエハ３にホウ素等のアクセプタ（P型ドーパント）を注入した典型的な場合では約1,000℃である。また、半導体ウエハ３の内部または表面下に添加されたドーパントを十分に活性化するためには、その領域の温度を所定時間に亘って活性化温度以上に維持する必要がある。この所定時間も、ドーパントの種類や量、半導体ウエハ３の材料によって異なりうるが、典型的なケースでは約10μsである。このように、活性化ステップでは、ドーパントが注入された半導体ウエハ３の内部または表面下の領域（典型的には半導体ウエハ３の表面下の10μmまでの領域）を、少なくとも10μsに亘って1000℃以上に昇温することが典型的な目標になる。 In the activation step, the semiconductor wafer 3 is irradiated with the laser pulse LP continuously from the surface melting step, so that the temperature inside or under the surface of the semiconductor wafer 3 into which the dopant is implanted is increased to a predetermined activation temperature or higher. , the dopant is activated. The activation temperature may vary depending on the type of dopant and the material of the semiconductor wafer 3 (silicon, silicon carbide, gallium nitride, etc.), but the most common method is to implant an acceptor (P-type dopant) such as boron into a silicon semiconductor wafer 3. In a typical case, the temperature is about 1,000℃. Furthermore, in order to sufficiently activate the dopant added inside or under the surface of the semiconductor wafer 3, it is necessary to maintain the temperature of that region at or above the activation temperature for a predetermined period of time. This predetermined time may also vary depending on the type and amount of dopant and the material of the semiconductor wafer 3, but is typically about 10 μs. Thus, in the activation step, the interior or subsurface region of the semiconductor wafer 3 into which the dopants have been implanted (typically up to 10 μm below the surface of the semiconductor wafer 3) is heated to 1000° C. for at least 10 μs. A typical goal is to increase the temperature above this level.
　活性化ステップは、ドーパントが注入された半導体ウエハ３の表面下の活性化領域の温度が活性化温度以上に上がった時に開始し、当該活性化領域の温度が活性化温度未満に下がった時に終了する。半導体ウエハ３の表面温度を示す図４は表面下の活性化領域の温度を示すものではないため、活性化ステップの開始タイミングと終了タイミングは目安として示されている。典型的には、図示されるように、活性化ステップは表面溶融ステップより短い。また、活性化ステップの開始タイミングは、典型的には表面溶融ステップの開始タイミングより遅い。更に、活性化ステップの終了タイミングは、表面溶融ステップの終了タイミングと実質的に等しい。但し、厳密には、活性化ステップが関わる半導体ウエハ３内の活性化領域の温度は、表面溶融ステップが関わる半導体ウエハ３の表面の温度より下がりにくいため、活性化ステップの終了タイミング（活性化領域が活性化温度未満に降温）は表面溶融ステップの終了タイミング（表面が融点未満に降温）より僅かに遅くなると考えられる。 The activation step starts when the temperature of the activation region under the surface of the semiconductor wafer 3 into which the dopant is implanted rises above the activation temperature, and ends when the temperature of the activation region falls below the activation temperature. do. Since FIG. 4, which shows the surface temperature of the semiconductor wafer 3, does not show the temperature of the activation region below the surface, the start timing and end timing of the activation step are shown as a guide. Typically, the activation step is shorter than the surface fusing step, as shown. Additionally, the start timing of the activation step is typically later than the start timing of the surface melting step. Furthermore, the end timing of the activation step is substantially equal to the end timing of the surface melting step. However, strictly speaking, the temperature of the activation region in the semiconductor wafer 3 involved in the activation step is less likely to drop than the temperature of the surface of the semiconductor wafer 3 involved in the surface melting step. The timing of the end of the surface melting step (the surface temperature decreases below the melting point) is considered to be slightly later than the end timing of the surface melting step (the surface temperature decreases below the melting point).
　なお、活性化領域に添加されたドーパントの量が通常より多い場合や、活性化領域が10μmより深い場合は、活性化ステップを10μsより長くすればよい。具体的には、レーザパルス走査部としてのガルバノスキャナ１４によるレーザパルスＬＰのＹ方向（ｙ方向）の走査速度を遅くすることで、活性化ステップを長くできる。あるいは、パルスレーザ装置２によるレーザパルスＬＰの発振周波数を800kHzより高くすることで同様の効果が得られる。活性化ステップを長くすると表面溶融ステップも必然的に長くなるが、間欠的なレーザパルスＬＰが照射されない非パルス期間における半導体ウエハ３の表面からの放熱等によって、半導体ウエハ３の表面が過熱状態となることが防止される（図示の例では表面温度が2,000℃以下に抑えられる）。このように、本実施形態によれば、活性化ステップの長さによらず表面溶融ステップを適切に実行できる。 Note that if the amount of dopant added to the activation region is larger than usual or if the activation region is deeper than 10 μm, the activation step may be made longer than 10 μs. Specifically, the activation step can be lengthened by slowing down the scanning speed of the laser pulse LP in the Y direction (y direction) by the galvano scanner 14 as a laser pulse scanning unit. Alternatively, the same effect can be obtained by setting the oscillation frequency of the laser pulse LP by the pulse laser device 2 higher than 800 kHz. If the activation step is lengthened, the surface melting step will inevitably be lengthened, but the surface of the semiconductor wafer 3 may become overheated due to heat radiation from the surface of the semiconductor wafer 3 during the non-pulse period when the intermittent laser pulse LP is not irradiated. (In the example shown, the surface temperature is kept below 2,000°C.) In this way, according to the present embodiment, the surface melting step can be appropriately performed regardless of the length of the activation step.
　本実施形態によれば、連続する表面溶融ステップおよび活性化ステップを通じて、一つのパルスレーザ装置２がレーザパルスＬＰを半導体ウエハ３に照射し続けることで、表面における溶融および表面下における活性化を併せて行える。 According to this embodiment, one pulsed laser device 2 continues to irradiate the semiconductor wafer 3 with laser pulses LP through the successive surface melting steps and activation steps, thereby combining melting on the surface and activation below the surface. You can do it.
　以上、本発明を実施形態に基づいて説明した。例示としての実施形態における各構成要素や各処理の組合せには様々な変形例が可能であり、そのような変形例が本発明の範囲に含まれることは当業者にとって自明である。 The present invention has been described above based on the embodiments. It will be obvious to those skilled in the art that various modifications can be made to the combinations of components and processes in the exemplary embodiments, and such modifications are within the scope of the present invention.
　なお、実施形態で説明した各装置や各方法の構成、作用、機能は、ハードウェア資源またはソフトウェア資源によって、あるいは、ハードウェア資源とソフトウェア資源の協働によって実現できる。ハードウェア資源としては、例えば、プロセッサ、ＲＯＭ、ＲＡＭ、各種の集積回路を利用できる。ソフトウェア資源としては、例えば、オペレーティングシステム、アプリケーション等のプログラムを利用できる。 Note that the configuration, operation, and function of each device and each method described in the embodiments can be realized by hardware resources or software resources, or by cooperation of hardware resources and software resources. As hardware resources, for example, a processor, ROM, RAM, and various integrated circuits can be used. As software resources, for example, programs such as operating systems and applications can be used.
　本発明は、レーザアニール装置等に関する。 The present invention relates to a laser annealing device and the like.
　１　レーザアニール装置、２　パルスレーザ装置、３　半導体ウエハ、４　ステージ装置、１１　ビームエキスパンダ、１３　ビーム整形光学素子、１４　ガルバノスキャナ、２０　光ファイバ、２２　レーザ光生成部、ＬＰ　レーザパルス。 1. Laser annealing device, 2. Pulse laser device, 3. Semiconductor wafer, 4. Stage device, 11. Beam expander, 13. Beam shaping optical element, 14. Galvano scanner, 20. Optical fiber, 22. Laser light generation unit, LP laser pulse.

Claims (6)

  1. 　パルスレーザ装置が発振するレーザパルスを半導体ウエハに照射し、複数の前記レーザパルスによって前記半導体ウエハの表面を融点以上に昇温して溶融させる表面溶融ステップと、
    　前記表面溶融ステップから継続して前記レーザパルスを前記半導体ウエハに照射し、更に複数の前記レーザパルスによって前記半導体ウエハの表面下を少なくとも所定時間に亘って所定の活性化温度以上に昇温し、前記半導体ウエハの表面下に添加されたドーパントを活性化する活性化ステップと、
    　を実行するレーザアニール装置。     a surface melting step of irradiating the semiconductor wafer with laser pulses emitted by a pulsed laser device, and heating the surface of the semiconductor wafer to a temperature above the melting point by the plurality of laser pulses to melt it;
    Continuing from the surface melting step, the semiconductor wafer is irradiated with the laser pulse, and the temperature below the surface of the semiconductor wafer is raised to a predetermined activation temperature or higher for at least a predetermined period of time by a plurality of the laser pulses, an activation step of activating dopants added below the surface of the semiconductor wafer;
    Laser annealing equipment that performs.
  2. 　前記パルスレーザ装置は、100kHz以上の周波数で前記レーザパルスを発振する、請求項１に記載のレーザアニール装置。 The laser annealing device according to claim 1, wherein the pulse laser device oscillates the laser pulse at a frequency of 100kHz or more.
  3. 　前記パルスレーザ装置は、光ファイバによって前記レーザパルスを発振するファイバレーザ装置である、請求項１に記載のレーザアニール装置。 The laser annealing device according to claim 1, wherein the pulse laser device is a fiber laser device that oscillates the laser pulse using an optical fiber.
  4. 　前記活性化ステップは、前記半導体ウエハの表面下の10μmまでの領域を少なくとも10μsに亘って1000℃以上に昇温する、請求項１から３のいずれかに記載のレーザアニール装置。 4. The laser annealing apparatus according to claim 1, wherein the activation step raises the temperature of a region up to 10 μm below the surface of the semiconductor wafer to 1000° C. or higher for at least 10 μs.
  5. 　パルスレーザ装置が発振するレーザパルスを半導体ウエハに照射し、複数の前記レーザパルスによって前記半導体ウエハの表面を融点以上に昇温して溶融させる表面溶融ステップと、
    　前記表面溶融ステップから継続して前記レーザパルスを前記半導体ウエハに照射し、更に複数の前記レーザパルスによって前記半導体ウエハの表面下を少なくとも所定時間に亘って所定の活性化温度以上に昇温し、前記半導体ウエハの表面下に添加されたドーパントを活性化する活性化ステップと、
    　からなるレーザアニール方法。     a surface melting step of irradiating the semiconductor wafer with laser pulses emitted by a pulsed laser device, and heating the surface of the semiconductor wafer to a temperature above the melting point by the plurality of laser pulses to melt it;
    Continuing from the surface melting step, the semiconductor wafer is irradiated with the laser pulse, and the temperature below the surface of the semiconductor wafer is raised to a predetermined activation temperature or higher for at least a predetermined period of time by a plurality of the laser pulses, an activation step of activating dopants added below the surface of the semiconductor wafer;
    A laser annealing method consisting of
  6. 　パルスレーザ装置が発振するレーザパルスを半導体ウエハに照射し、複数の前記レーザパルスによって前記半導体ウエハの表面を融点以上に昇温して溶融させる表面溶融ステップと、
    　前記表面溶融ステップから継続して前記レーザパルスを前記半導体ウエハに照射し、更に複数の前記レーザパルスによって前記半導体ウエハの表面下を少なくとも所定時間に亘って所定の活性化温度以上に昇温し、前記半導体ウエハの表面下に添加されたドーパントを活性化する活性化ステップと、
    　をコンピュータに実行させるレーザアニールプログラム。     a surface melting step of irradiating the semiconductor wafer with laser pulses emitted by a pulsed laser device, and heating the surface of the semiconductor wafer to a temperature above the melting point by the plurality of laser pulses to melt it;
    Continuing from the surface melting step, the semiconductor wafer is irradiated with the laser pulse, and the temperature below the surface of the semiconductor wafer is raised to a predetermined activation temperature or higher for at least a predetermined period of time by a plurality of the laser pulses, an activation step of activating dopants added below the surface of the semiconductor wafer;
    A laser annealing program that runs on a computer.
PCT/JP2023/022020 2022-07-19 2023-06-14 Laser annealing apparatus, laser annealing method, and laser annealing program WO2024018786A1 (en)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005223301A (en) * 2003-06-24 2005-08-18 Fuji Electric Device Technology Co Ltd Method for manufacturing semiconductor device
JP2020202242A (en) * 2019-06-07 2020-12-17 住友重機械工業株式会社 Laser annealing method and laser control device

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005223301A (en) * 2003-06-24 2005-08-18 Fuji Electric Device Technology Co Ltd Method for manufacturing semiconductor device
JP2020202242A (en) * 2019-06-07 2020-12-17 住友重機械工業株式会社 Laser annealing method and laser control device

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