WO2024077749A1 - 激光切割装置以及晶圆切割方法 - Google Patents

激光切割装置以及晶圆切割方法 Download PDF

Info

Publication number
WO2024077749A1
WO2024077749A1 PCT/CN2022/137439 CN2022137439W WO2024077749A1 WO 2024077749 A1 WO2024077749 A1 WO 2024077749A1 CN 2022137439 W CN2022137439 W CN 2022137439W WO 2024077749 A1 WO2024077749 A1 WO 2024077749A1
Authority
WO
WIPO (PCT)
Prior art keywords
laser
substrate
wafer
acts
cutting
Prior art date
Application number
PCT/CN2022/137439
Other languages
English (en)
French (fr)
Inventor
彭杨
陈帮
郭万里
Original Assignee
武汉新芯集成电路制造有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 武汉新芯集成电路制造有限公司 filed Critical 武汉新芯集成电路制造有限公司
Publication of WO2024077749A1 publication Critical patent/WO2024077749A1/zh

Links

Images

Classifications

    • 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
    • B23K26/36—Removing material
    • B23K26/38—Removing material by boring or cutting
    • 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
    • B23K26/70—Auxiliary operations or equipment
    • B23K26/702—Auxiliary equipment
    • 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
    • H01L21/70—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
    • H01L21/77—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate
    • H01L21/78—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate with subsequent division of the substrate into plural individual devices
    • 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
    • B23K2101/00—Articles made by soldering, welding or cutting
    • B23K2101/36—Electric or electronic devices
    • B23K2101/40—Semiconductor devices

Definitions

  • the present invention relates to the field of semiconductor integrated circuit manufacturing, and in particular to a laser cutting device and a wafer cutting method.
  • the mainstream cutting methods include mechanical cutting, laser cutting and plasma etching; among them, plasma etching has the advantages of fast processing speed, good stress healing effect after etching and high etching depth-to-width ratio (wafer thickness is less than 100 ⁇ m), and has become the mainstream wafer cutting method; however, there are many layers of materials in the wafer that cannot be processed by plasma etching, such as the metal layer on the cutting path, low dielectric constant materials and oxides, but can be more easily ablated by laser.
  • a method combining plasma etching and laser cutting is used to cut the wafer.
  • a layer of water-soluble laser protection liquid needs to be coated on the surface of the wafer, and the insulating layer on the substrate and the metal layer in the insulating layer are cut by laser, and the substrate is etched by plasma.
  • a wafer 10 is placed on a carrier 11, and a laser 12 is arranged above the wafer 10.
  • the laser L1 emitted by the laser 12 is focused on the cutting path (not shown) of the wafer 10 after passing through a focusing unit 13, so as to cut the insulating layer on the cutting path and the metal layer in the insulating layer.
  • the instantaneous high temperature generated by laser cutting vaporizes the surface material of the wafer 10, and the gaseous material condenses to form slag when it evaporates and is cooled.
  • the thermal effect generated during the laser processing will affect the surface morphology of the cutting location. The above problems will cause the flatness of the surface of the wafer 10 to deteriorate, thereby affecting the subsequent bonding process.
  • the object of the present invention is to provide a laser cutting device and a wafer cutting method, so that While maintaining high cutting efficiency, it can also improve the surface flatness of the cut wafer.
  • the present invention provides a laser cutting device for cutting a substrate fixed on a carrier, the laser cutting device comprising:
  • a laser wherein the substrate is disposed between the laser and the carrier, the laser is used to emit a first laser and a second laser, the first laser acts on the substrate, the second laser acts on a position on the substrate where the first laser acts, and a difference T between a time when the second laser acts on a position on the substrate and a time when the first laser acts on a corresponding position on the substrate is greater than or equal to 0;
  • the first laser is used to cut the substrate
  • the second laser is used to remove byproducts generated when the first laser cuts the substrate.
  • a pulse width of the first laser is greater than a pulse width of the second laser and a range in which the first laser acts on the substrate is smaller than a range in which the second laser acts on the substrate, so that the first laser is used to cut the substrate and the second laser is used to remove byproducts of the first laser.
  • a range in which the second laser acts on the substrate is 1 ⁇ m to 7 ⁇ m larger than a range in which the first laser acts on the substrate.
  • the at least two lasers are used to emit the first laser and the second laser respectively.
  • the laser emitting the first laser is a picosecond laser
  • the laser emitting the second laser is a femtosecond laser
  • the laser cutting device further comprises a focusing spectrometer unit disposed between the substrate and the laser, the focusing spectrometer unit being used to adjust the distance in the horizontal direction between an emission path of the first laser close to the substrate and an emission path of the second laser close to the substrate.
  • the laser cutting device further comprises a focusing unit, which is arranged between the focusing and splitting unit and the laser, and the focusing unit is used to focus the first laser and the second laser on the focusing and splitting unit.
  • the present invention also provides a wafer cutting method, comprising:
  • the first laser is used to cut the wafer
  • the second laser is used to remove byproducts generated when the first laser cuts the wafer.
  • the pulse width of the first laser is greater than the pulse width of the second laser and the range of the first laser acting on the wafer is smaller than the range of the second laser acting on the wafer, so that the first laser is used to cut the substrate and the second laser is used to remove the first laser byproducts.
  • the first laser is a picosecond laser
  • the second laser is a femtosecond laser
  • the wafer includes a substrate and a dielectric layer formed on the substrate, wherein a conductive material is formed in the dielectric layer; the dielectric layer and the conductive material on the wafer are cut using the first laser and the second laser, and the substrate on the wafer is cut using an etching process.
  • the laser cutting device of the present invention comprises a laser, wherein the substrate is arranged between the laser and the supporting platform, and the laser is used to emit a first laser and a second laser, wherein the first laser acts on the substrate, and the second laser acts on the position where the first laser acts on the substrate, and the difference T between the time when the second laser acts on the position on the substrate and the time when the first laser acts on the corresponding position on the substrate is greater than or equal to 0; wherein the first laser is used to cut the substrate, and the second laser is used to remove by-products generated when the first laser cuts the substrate, so as to ensure high cutting efficiency while improving the surface flatness of the substrate after cutting.
  • the wafer cutting method of the present invention comprises providing a first laser and a second laser, wherein the first laser acts on the wafer, and the second laser acts on the position on the wafer where the first laser acts, and the time at which the second laser acts on the position on the wafer is the same as the time at which the first laser acts on the wafer.
  • the time difference T between corresponding positions on the wafer is greater than or equal to 0; wherein the first laser is used to cut the wafer, and the second laser is used to remove by-products generated when the first laser cuts the wafer, so as to ensure high cutting efficiency while improving the surface flatness of the wafer after cutting.
  • FIG1 is a schematic diagram of a laser cutting device
  • FIG2 is a schematic diagram of a laser cutting device according to an embodiment of the present invention.
  • FIG. 3 is a flow chart of a wafer cutting method according to an embodiment of the present invention.
  • An embodiment of the present invention provides a laser cutting device for cutting a substrate fixed on a supporting platform, the laser cutting device comprising: a laser, the substrate is arranged between the laser and the supporting platform, the laser is used to emit a first laser and a second laser, the first laser acts on the substrate, the second laser acts on the position where the first laser acts on the substrate, and the difference T between the time when the second laser acts on the position on the substrate and the time when the first laser acts on the corresponding position on the substrate is greater than or equal to 0; wherein the first laser is used to cut the substrate, and the second laser is used to remove by-products generated when the first laser cuts the substrate.
  • the laser cutting device provided in this embodiment is introduced in detail below.
  • the bearing surface of the bearing platform faces the laser, and the substrate is fixed to the bearing surface of the bearing platform. On the carrying surface, the substrate is arranged between the laser and the carrying platform.
  • the carrying platform is provided with an adsorption component or a clamping component, or both are provided with an adsorption component and a clamping component, so that the substrate can be fixed on the carrying platform by the adsorption component and/or the clamping component.
  • the substrate may be a glass substrate, a ceramic substrate, a wafer or various substrates known to those skilled in the art.
  • the substrate is a wafer, and the wafer comprises a substrate and a dielectric layer disposed on the substrate, wherein a conductive material is formed in the dielectric layer.
  • the wafer comprises a plurality of chip areas and cutting paths connecting adjacent chip areas, and the chips are obtained after the cutting paths are cut.
  • the pulse width of the first laser is greater than the pulse width of the second laser and the range in which the first laser acts on the substrate is smaller than the range in which the second laser acts on the substrate, so that the first laser is used to cut the substrate and the second laser is used to remove byproducts generated when the first laser cuts the substrate.
  • the magnitude of the thermal effect is closely related to the pulse width of the laser. For example, when the laser acts on the material, the energy is first absorbed by the excited electrons, and then the energy is transferred to the lattice through the electron lattice scattering. The time scale of this process is tens of picoseconds. After that, the heat is transferred between the lattices, causing the temperature of the surrounding lattices to rise, causing the material to change into flames and vaporize.
  • the pulse width is much longer than the time of electron lattice scattering, during the pulse action, there is enough time for the energy to be transferred from the electrons to the lattice and diffuse between the lattices, causing the lattice temperature to gradually rise and melt and vaporize.
  • the pulses generated by femtosecond lasers have shorter pulse widths. At this time, the pulse action time is much shorter than the time of electron lattice scattering.
  • the laser pulse is completed, the energy is not transferred to the lattice in time. At this time, the lattice is "cold", and the material dissociation caused by the femtosecond laser occurs within a few picoseconds.
  • the picosecond pulse width is between the nanosecond and femtosecond pulse widths. When the picosecond laser interacts with the material, the thermal effect generated is between that of the nanosecond laser and the femtosecond laser.
  • the pulse width of the first laser is greater than the electron lattice scattering time of the substrate, so that the first laser is used to cut the substrate.
  • the first laser cuts the substrate, a deep groove is cut on the substrate to ensure high cutting efficiency.
  • the thermal effect is obvious, resulting in various by-products on the surface of the groove and the surface of the substrate near the groove.
  • the by-products may be slag and curling generated at the top corner of the groove.
  • the second laser is basically not used to continue cutting the substrate to avoid the continued accumulation of byproducts. Instead, the second laser acts on the substrate in a larger range than the first laser, so that various byproducts on the groove surface and the substrate surface near the groove are melted and gasified, thereby achieving the effect of removing the byproducts generated when the first laser cuts the substrate, thereby improving the surface flatness of the substrate after cutting.
  • the horizontal distance between the emission path of the first laser close to the substrate and the emission path of the second laser close to the substrate is set to L, L is greater than or equal to a preset distance, and the preset distance can achieve that the position of the second laser acting on the substrate can cover the position of the first laser acting on the substrate or the position of the second laser acting on the substrate intersects with the position of the first laser acting on the substrate.
  • the position of the second laser acting on the substrate covers the position of the first laser acting on the substrate or the position of the second laser acting on the substrate intersects with the position of the first laser acting on the substrate; when L is greater than the preset distance, the position of the second laser acting on the substrate does not overlap or intersect with the position of the first laser acting on the substrate.
  • the range of the second laser acting on the substrate is 1 ⁇ m to 7 ⁇ m larger than the range of the first laser acting on the substrate.
  • the first laser acts on the substrate and the second laser acts on the same position on the substrate at the same time, and L is equal to a preset distance, so that the first laser is used to cut the substrate and the second laser is used to remove byproducts generated when the first laser cuts the substrate.
  • the second laser acts on the same position on the substrate as the first laser, and there is a time lag between the second laser and the first laser acting on the same position on the substrate, and L can be equal to the preset distance or greater than the preset distance.
  • L is equal to the preset distance
  • the same position on the substrate is located at the same time of the first laser and the second laser. In the action range, the first laser is emitted first and then the second laser is emitted, so that the second laser acts on the substrate after the first laser acts on the substrate.
  • the first laser and the second laser are emitted alternately at pulse intervals. After the first laser acts on the action point of the substrate, the substrate remains stationary. The second laser is emitted in the gap between two adjacent first lasers, so that the second laser acts on the action point of the substrate (the same position on the substrate, corresponding to point M in FIG. 1 in this embodiment). In this embodiment, after the first laser and the second laser act alternately on the action point (point M) of the substrate in sequence to complete the cutting and by-product removal at the position of the action point (point M) of the substrate, the substrate is moved to perform cutting at the next position of the substrate. In one embodiment, L is greater than the preset distance, and the same position on the substrate is not simultaneously within the action range of the first laser and the second laser.
  • the second laser acts on the same position on the substrate as that on which the first laser acted.
  • the substrate moves in a direction away from the next position on the substrate (corresponding to point B in FIG. 2 in this embodiment).
  • the second laser removes the byproducts generated by the first laser cutting the action point (point A) of the substrate.
  • the second laser acts on the same position on the substrate as the first laser.
  • the second laser acts on the substrate after the first laser acts on the substrate, which corresponds to a cycle.
  • the first laser acts on the substrate x times
  • the second laser acts on the substrate y times
  • the cycle is repeated N times, wherein x ⁇ 1, y ⁇ 1, N ⁇ 1, and x, y, and N are all integers.
  • the above cycle is repeated until the substrate is cut off, so that the substrate can be cut and by-products near the substrate can be removed, thereby polishing the surface near the cutting groove of the substrate, avoiding the accumulation of by-products generated during the cutting process, and improving the flatness of the cutting surface of the substrate.
  • step S21 the first laser acts on the substrate once to cut the substrate; then, step S22: the second laser acts on the substrate once to remove the byproducts generated when the first laser cuts the substrate, completing the cutting and Removal of by-products.
  • step S21 the first laser acts on the substrate once to cut the substrate; then, step S22: the second laser acts on the substrate once to remove the by-products generated when the first laser cuts the substrate; finally, step S21 to step S22 are cycled once to complete the cutting of the substrate and the removal of by-products.
  • step S21 the first laser acts on the substrate twice to cut the substrate; then, step S22: the second laser acts on the substrate three times to remove the by-products generated when the first laser cuts the substrate; finally, step S21 to step S22 are cycled three times to complete the cutting of the substrate and the removal of by-products.
  • the emission path of the first laser close to the substrate and the emission path of the second laser close to the substrate are separated in the horizontal direction by a distance L greater than a preset distance, and the substrate moves in a direction from the substrate action point to the next position of the substrate.
  • Step S21 to Step S22 are cycled N-1 times to complete the cutting of the substrate and the removal of by-products.
  • the laser may be one or at least two.
  • the one laser sequentially and alternately emits the first laser and the second laser, or the one laser simultaneously emits the first laser and the second laser.
  • the at least two lasers are respectively used to emit the first laser and the second laser, or the at least two lasers are respectively used to alternately emit the first laser and the second laser, or the at least two lasers are spaced a certain distance apart in the horizontal direction and simultaneously emit the first laser and/or the second laser.
  • the lasers when there are at least two lasers, the lasers may be at least two of nanosecond lasers, picosecond lasers and femtosecond lasers, and the pulse widths of the lasers emitted by the nanosecond lasers, the picosecond lasers and the femtosecond lasers decrease in sequence. That is, the nanosecond laser and the picosecond laser may be used to emit nanosecond laser and picosecond laser, respectively, to cut the substrate, or the nanosecond laser and the femtosecond laser may be used to emit nanosecond laser and femtosecond laser, respectively, to cut the substrate and clean it.
  • the picosecond laser and the femtosecond laser are used to respectively emit picosecond laser and femtosecond laser to cut the substrate and remove byproducts, or the nanosecond laser, the picosecond laser and the femtosecond laser are used in sequence to respectively emit nanosecond laser, picosecond laser and femtosecond laser to cut the substrate and remove byproducts.
  • the laser emitting the first laser is a picosecond laser
  • the laser emitting the second laser is a femtosecond laser.
  • the laser pulse width emitted by the nanosecond laser is the largest, the laser emitted by the nanosecond laser can not only cut a deep groove on the substrate, but can even completely cut off the substrate; and the pulse width emitted by the picosecond laser is between the femtosecond laser and the nanosecond laser, and the cutting force of the picosecond laser is between the cutting force of the nanosecond laser and the cutting force of the femtosecond laser. Therefore, in order to make the pulse width of the first laser greater than the electron lattice scattering time of the substrate and use the first laser to cut the substrate, the laser emitting the first laser can be a nanosecond laser or a picosecond laser.
  • the laser pulse width emitted by the femtosecond laser is smaller than the electron lattice scattering time of the substrate, when the laser emitted by the femtosecond laser acts on the substrate, it basically does not further deepen the depth of the groove cut by the previous laser, but vaporizes the slag on the groove surface and the substrate surface close to the groove and the curled edge on the top of the groove, thereby removing the by-products on the groove surface and the substrate surface close to the groove, and has a better polishing effect on the substrate surface. Therefore, it is preferred to use a femtosecond laser to emit the second laser to remove the by-products generated when the first laser cuts the substrate.
  • the laser cutting device further includes a focusing spectrometer, which is disposed between the substrate and the laser, and is used to adjust the distance between the emission path of the first laser close to the substrate and the emission path of the second laser close to the substrate in the horizontal direction.
  • a focusing spectrometer which is disposed between the substrate and the laser, and is used to adjust the distance between the emission path of the first laser close to the substrate and the emission path of the second laser close to the substrate in the horizontal direction.
  • the emission path of the second laser emitted by the laser close to the substrate can be aligned with the emission path of the first laser close to the substrate.
  • the distance between the emission paths of the substrate in the horizontal direction is reduced so that the second laser can remove the slag and the curling more quickly, thereby avoiding the gradual accumulation of the slag and the curling.
  • the focusing and light splitting unit may include a lens and a component for fixing the lens.
  • the laser cutting device also includes a focusing unit, which is arranged between the focusing and spectroscopic unit and the laser, and the focusing unit is used to focus the first laser and the second laser emitted by the laser on the focusing and spectroscopic unit respectively; and the focusing and spectroscopic unit can focus the first laser and the second laser incident on the focusing and spectroscopic unit again respectively, so that the first laser and the second laser incident on the substrate are more concentrated, thereby making the position of cutting the substrate more precise.
  • a focusing unit which is arranged between the focusing and spectroscopic unit and the laser, and the focusing unit is used to focus the first laser and the second laser emitted by the laser on the focusing and spectroscopic unit respectively; and the focusing and spectroscopic unit can focus the first laser and the second laser incident on the focusing and spectroscopic unit again respectively, so that the first laser and the second laser incident on the substrate are more concentrated, thereby making the position of cutting the substrate more precise.
  • the focusing unit may include a lens and a component for fixing the lens.
  • first laser and the second laser When the first laser and the second laser are emitted from the laser, they may be substantially parallel to each other or not. After being processed by the focusing and spectroscopic unit, the first laser and the second laser emitted from the focusing and spectroscopic unit to the substrate are parallel to each other, so that the cutting paths of the first laser and the second laser emitted by the laser on the substrate remain consistent, thereby avoiding cutting deviation.
  • two lasers are arranged above the substrate 20 on the carrier 21, which may be a picosecond laser 221 and a femtosecond laser 222, respectively.
  • the picosecond laser 221 and the femtosecond laser 222 are arranged at intervals.
  • the first laser L2 emitted by the picosecond laser 221 is focused by the first focusing unit 241 and incident on the focusing and spectroscopic unit 23, and is emitted from the focusing and spectroscopic unit 23 to the substrate 20.
  • the second laser L3 emitted by the femtosecond laser 222 is focused by the second focusing unit 242 and incident on the focusing and spectroscopic unit 23, and is emitted from the focusing and spectroscopic unit 23 to the substrate 20.
  • the first laser L2 and the second laser L3 are incident on the same cutting path on the substrate 20.
  • the second laser L3 acts on the same action point (point A) on the substrate 20.
  • the emission path of the first laser L2 close to the substrate and the emission path of the second laser L3 close to the substrate are separated by a distance L in the horizontal direction (X direction).
  • the distance L is greater than the preset distance.
  • the carrier 21 is moved along the X direction so that the The substrate 20 moves in a direction away from the action point (point A) of the substrate 20 toward the next position (point B) of the substrate.
  • the second laser L3 clears the by-products produced by the first laser L2 cutting the action point (point A) of the substrate 20, thereby achieving the first laser L2 cutting the cutting path first, and the second laser L3 follows along the cutting path of the first laser L2 to cut the same cutting path.
  • the laser cutting device of the present invention includes a laser, and the substrate is arranged between the laser and the supporting platform.
  • the laser is used to emit a first laser and a second laser, the first laser acts on the substrate, and the second laser acts on the position where the first laser acts on the substrate, and the time difference T between the position where the second laser acts on the substrate and the position where the first laser acts on the substrate is greater than or equal to 0; wherein the first laser is used to cut the substrate, and the second laser is used to remove the by-products generated when the first laser cuts the substrate, so as to ensure high cutting efficiency while improving the surface flatness of the substrate after cutting.
  • An embodiment of the present invention provides a wafer cutting method.
  • the wafer cutting method includes:
  • Step S1 providing a wafer, wherein the wafer is fixed on a carrier;
  • Step S2 providing a first laser and a second laser, wherein the first laser acts on the wafer, and the second laser acts on the position on the wafer where the first laser acts, and the difference T between the time when the second laser acts on the position on the wafer and the time when the first laser acts on the corresponding position on the wafer is greater than or equal to 0; wherein the first laser is used to cut the wafer, and the second laser is used to remove byproducts generated when the first laser cuts the wafer.
  • the wafer cutting method is described in detail below.
  • step S1 a wafer is provided and the wafer is fixed on a carrier.
  • the carrying surface of the carrying platform faces the laser, the wafer is fixed on the carrying surface of the carrying platform, and the wafer is arranged between the laser and the carrying platform.
  • the description of the laser refers to the above-mentioned laser cutting device, which will not be repeated here.
  • the laser is fixed and the carrier is moved horizontally so that the carrier is close to the laser in the horizontal direction.
  • the wafer includes a substrate and a dielectric layer formed on the substrate, wherein a conductive material is formed in the dielectric layer.
  • the wafer includes a plurality of chip regions and cutting paths connecting adjacent chip regions, and chips are obtained after the cutting paths are cut.
  • a first laser and a second laser are provided, wherein the first laser acts on the wafer, and the second laser acts on the position on the wafer where the first laser acts, and a difference T between a time when the second laser acts on the position on the wafer and a time when the first laser acts on the corresponding position on the wafer is greater than or equal to 0; wherein the first laser is used to cut the wafer, and the second laser is used to remove byproducts generated when the first laser cuts the wafer.
  • the pulse width of the first laser is greater than the pulse width of the second laser and the range in which the first laser acts on the wafer is smaller than the range in which the second laser acts on the wafer, so that the first laser is used to cut the wafer and the second laser is used to remove byproducts generated when the first laser cuts the wafer.
  • the horizontal distance between the emission path of the first laser close to the wafer and the emission path of the second laser close to the wafer is set to L, L is greater than or equal to a preset distance, and the preset distance can achieve that the position of the second laser acting on the wafer can cover the position of the first laser acting on the wafer or the position of the second laser acting on the wafer intersects with the position of the first laser acting on the wafer.
  • the position of the second laser acting on the wafer covers the position of the first laser acting on the wafer or the position of the second laser acting on the wafer intersects with the position of the first laser acting on the wafer; when L is greater than the preset distance, the position of the second laser acting on the wafer does not overlap or intersect with the position of the first laser acting on the wafer.
  • the range of the second laser acting on the wafer is 1 ⁇ m to 7 ⁇ m larger than the range of the first laser acting on the wafer.
  • the first laser acts on the wafer while the second laser acts on the same position on the wafer, and L is equal to the preset distance, so that the first laser is used to cut the wafer while the second laser is used to clear the first A byproduct of laser cutting of the wafer.
  • the second laser acts on the same position on the wafer as the first laser, and there is a time lag between the second laser and the first laser acting on the same position on the wafer, and L can be equal to the preset distance or greater than the preset distance. In one embodiment, L is equal to the preset distance, and the same position on the wafer is simultaneously within the action range of the first laser and the second laser.
  • the first laser and the second laser are alternately emitted at pulse intervals. After the first laser acts on the action point of the wafer, the wafer remains stationary. The second laser is emitted in the gap between two adjacent first lasers, so that the second laser acts on the action point of the wafer (the same position on the wafer, corresponding to point M in FIG. 1 in this embodiment).
  • the first laser and the second laser act alternately on the action point (point M) of the wafer in sequence to complete the cutting and by-product removal of the position of the action point (point M) of the wafer, , move the wafer to cut the next position of the wafer; in another embodiment, L is greater than the preset distance, and the same position on the wafer is not located within the action range of the first laser and the second laser at the same time.
  • the wafer moves in a direction away from the next position on the wafer (corresponding to point B in FIG. 2 in this embodiment).
  • the second laser removes the by-products generated by the action point (point A) of the first laser cutting the wafer.
  • the second laser acts on the same position on the wafer as the first laser, and the number of times the first laser acts on the wafer in the gap between two adjacent times the second laser acts on the wafer is x, and the number of times the second laser acts on the wafer in the gap between two adjacent times the first laser acts on the wafer is y.
  • the second laser acts on the wafer again, which corresponds to a cycle.
  • the number of times the cycle is repeated is N, where x ⁇ 1, y ⁇ 1, N ⁇ 1, x, y, and N are all integers.
  • the above cycle is repeated until the wafer is cut off, which can achieve cutting of the wafer and removal of by-products near the wafer, thereby polishing the surface near the wafer cutting groove, avoiding the accumulation of by-products generated during the cutting process, and improving the flatness of the wafer cutting surface.
  • step S21 the first laser acts on the wafer once to cut the wafer; then, step S22: the second laser acts on the wafer once to remove the byproducts generated when the first laser cuts the wafer, completing the cutting of the wafer and the removal of the byproducts.
  • step S21 the first laser acts on the wafer once to cut the wafer; then, step S22: the second laser acts on the wafer once to remove the byproducts generated when the first laser cuts the wafer; finally, step S21 to step S22 are cycled once to complete the cutting of the wafer and the removal of the byproducts.
  • step S21 the first laser acts on the wafer twice to cut the wafer; then, step S22: the second laser acts on the wafer three times to clean up the by-products generated when the first laser cuts the wafer; finally, step S21 to step S22 are cycled three times to complete the cutting of the wafer and the cleaning of the by-products.
  • the emission path of the first laser close to the wafer and the emission path of the second laser close to the wafer are separated in the horizontal direction by a distance L greater than a preset distance, and the wafer moves in a direction from the wafer action point to the next position of the wafer.
  • Step S21 to Step S22 are cycled N-1 times to complete the cutting of the wafer and the removal of by-products.
  • the first laser is a picosecond laser
  • the second laser is a femtosecond laser
  • the nanosecond laser has the largest pulse width, so it can not only cut a deep groove on the wafer, but even completely cut the wafer off.
  • the pulse width of the picosecond laser is between that of the femtosecond laser and the nanosecond laser.
  • the picosecond laser cutting force is between the nanosecond laser cutting force and the femtosecond laser cutting force. Therefore, in order to make the pulse width of the first laser greater than the electron lattice scattering time of the wafer so that the first laser is used to cut the wafer, the first laser can be a nanosecond laser or a picosecond laser.
  • the laser pulse width of the femtosecond laser is smaller than the electron lattice scattering time of the wafer, when the femtosecond laser acts on the wafer, it basically does not further deepen the depth of the groove previously cut by the laser. Instead, the slag on the groove surface and the wafer surface close to the groove and the curled edge at the top of the groove are vaporized, thereby removing the by-products on the groove surface and the wafer surface close to the groove, and achieving a better polishing effect on the wafer surface. Therefore, it is preferred to use a femtosecond laser to remove the by-products generated when the first laser cuts the wafer.
  • the dielectric layer and the conductive material on the cutting path can be cut by using a picosecond laser emitted by a picosecond laser, and then the surface of the wafer can be polished by using a femtosecond laser emitted by a femtosecond laser, and then the substrate on the cutting path can be cut by using a dry etching (such as plasma etching) or wet etching process; or, the cutting path can be cut by using a nanosecond laser emitted by a nanosecond laser, and then the surface of the wafer can be polished by using a femtosecond laser emitted by the femtosecond laser.
  • a dry etching such as plasma etching
  • wet etching process wet etching process
  • the cutting path can be cut by using a nanosecond laser emitted by a nanosecond laser, and then the surface of the wafer can be polished by using a femtosecond laser emitted by the femtosecond laser.
  • the wafer cutting method further includes: covering the surface of the wafer with a protective layer, the protective layer is used to protect the area outside the cutting path (including the chip area) from being etched when the substrate on the cutting path is cut by the etching process.
  • the protective layer can also protect the area outside the cutting path during laser cutting, and prevent the slag generated by the laser cutting from adhering to the area outside the cutting path.
  • the material of the protective layer can be a water-soluble resin.
  • the wafer cutting method of the present invention provides a first laser and a second laser, wherein the first laser acts on the wafer, and the second laser acts on the position where the first laser acts on the wafer, and the difference T between the time when the second laser acts on the position on the wafer and the time when the first laser acts on the position on the wafer is greater than or equal to 0; wherein the first laser is used to cut the wafer, and the second laser is used to remove the first laser cutting the wafer.
  • the by-product produced during the rounding process ensures high cutting efficiency while improving the surface flatness of the cut wafer.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Plasma & Fusion (AREA)
  • Mechanical Engineering (AREA)
  • General Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Laser Beam Processing (AREA)
  • Processing Of Stones Or Stones Resemblance Materials (AREA)

Abstract

本发明提供了一种激光切割装置以及晶圆切割方法，所述激光切割装置用于对固定于承载台上的基板进行切割，所述激光切割装置包括：激光器，所述激光器与所述承载台之间设置有所述基板，所述激光器用于发射第一激光和第二激光，所述第一激光作用于所述基板，所述第二激光作用于所述第一激光作用在所述基板上的位置，且所述第二激光作用于所述基板上的位置的时间与所述第一激光作用在所述基板上的相应位置的时间之差T大于等于0；其中，所述第一激光用于切割所述基板，所述第二激光用于清除所述第一激光切割所述基板时产生的副产物。本发明的技术方案使得在确保高切割效率的同时，还能提高切割后的晶圆表面平整度。

Description

激光切割装置以及晶圆切割方法 技术领域
本发明涉及半导体集成电路制造领域，特别涉及一种激光切割装置以及晶圆切割方法。
背景技术
在3D IC工艺中，为了实现芯片与晶圆之间的键合，需要将完整的晶圆切割成芯片，再通过键合技术将不同功能的芯片与晶圆连接，减小芯片面积，提高集成度。目前，主流的切割方法包含机械切割、激光切割和等离子体刻蚀；其中，等离子体刻蚀具有加工速度快、刻蚀后应力愈合效果好以及刻蚀深宽比高(晶圆厚度小于100μm)等优点，成为主流晶圆切割方法；但是，晶圆中有许多层材料不能采用等离子体刻蚀进行处理，例如，切割道上的金属层、低介电常数的材料以及氧化物等，但可以更容易被激光烧蚀。因此，采用等离子体刻蚀与激光切割相结合的方法切割晶圆，在对晶圆进行切割时，需要在晶圆表面涂布一层水溶性激光保护液，采用激光切割衬底上的绝缘层以及位于绝缘层中的金属层，采用等离子体刻蚀衬底。
参阅图1，在现有的激光切割装置中，晶圆10放置在承载台11上，激光器12设置于晶圆10的上方，激光器12发射的激光L1经聚焦单元13后聚焦在晶圆10的切割道(未图示)上，以对切割道上的绝缘层以及位于绝缘层中的金属层进行切割。其中，激光切割产生的瞬时高温将晶圆10表面物质气化，气态物质挥发时遇冷凝结形成熔渣，并且，激光加工过程中产生的热效应会影响切割处的表面形貌，上述问题均会导致晶圆10表面的平整度变差，从而影响后续键合制程。
因此，如何对现有的激光切割装置进行改进，以在确保高切割效率的同时，还能提高切割后的晶圆表面平整度是目前亟需解决的问题。
发明内容
本发明的目的在于提供一种激光切割装置以及晶圆切割方法，使得在确 保高切割效率的同时，还能提高切割后的晶圆表面平整度。
为实现上述目的，本发明提供了一种激光切割装置，用于对固定于承载台上的基板进行切割，所述激光切割装置包括：
激光器，所述激光器与所述承载台之间设置有所述基板，所述激光器用于发射第一激光和第二激光，所述第一激光作用于所述基板，所述第二激光作用于所述第一激光作用在所述基板上的位置，且所述第二激光作用于所述基板上的一位置的时间与所述第一激光作用在所述基板上的相应位置的时间之差T大于等于0；
其中，所述第一激光用于切割所述基板，所述第二激光用于清除所述第一激光切割所述基板时产生的副产物。
可选地，所述第一激光的脉宽大于所述第二激光的脉宽且所述第一激光作用在所述基板上的范围小于所述第二激光作用在所述基板上的范围，以使所述第一激光用于切割所述基板、所述第二激光用于清除所述第一激光副产物。
可选地，所述第二激光作用在所述基板上的范围比所述第一激光作用在所述基板上的范围大1μm～7μm。
可选地，所述激光器至少两个，所述至少两个激光器分别用于发射所述第一激光和所述第二激光。
可选地，发射所述第一激光的激光器为皮秒激光器，发射所述第二激光的激光器为飞秒激光器。
可选地，所述激光切割装置还包括聚焦分光单元，设置于所述基板与所述激光器之间，所述聚焦分光单元用于调整所述第一激光的靠近所述基板的发射路径和所述第二激光的靠近所述基板的发射路径在水平方向上之间的距离。
可选地，所述激光切割装置还包括聚焦单元，设置于所述聚焦分光单元与所述激光器之间，所述聚焦单元用于将所述第一激光和所述第二激光聚焦在所述聚焦分光单元上。
本发明还提供一种晶圆切割方法，包括：
提供一晶圆，所述晶圆固定于承载台上；
提供第一激光和第二激光，所述第一激光作用于所述晶圆，所述第二激光作用于所述第一激光作用在所述晶圆上的位置，且所述第二激光作用于所述晶圆上的一位置的时间与所述第一激光作用在所述晶圆上的相应位置的时间之差T大于等于0；
其中，所述第一激光用于切割所述晶圆，所述第二激光用于清除所述第一激光切割所述晶圆时产生的副产物。
可选地，所述第一激光的脉宽大于所述第二激光的脉宽且所述第一激光作用在所述晶圆上的范围小于所述第二激光作用在所述晶圆上的范围，以使所述第一激光用于切割所述基板、所述第二激光用于清除所述第一激光副产物。
可选地，所述第一激光为皮秒激光，所述第二激光为飞秒激光。
可选地，所述晶圆包括衬底以及形成于所述衬底上的介质层，所述介质层中形成有导电材料；采用所述第一激光和所述第二激光切割所述晶圆上的介质层和导电材料，并采用刻蚀工艺切割所述晶圆上的所述衬底。
与现有技术相比，本发明的技术方案具有以下有益效果：
1、本发明的激光切割装置，由于包括激光器，所述激光器与所述承载台之间设置有所述基板，所述激光器用于发射第一激光和第二激光，所述第一激光作用于所述基板，所述第二激光作用于所述第一激光作用在所述基板上的位置，且所述第二激光作用于所述基板上的位置的时间与所述第一激光作用在所述基板上的相应位置的时间之差T大于等于0；其中，所述第一激光用于切割所述基板，所述第二激光用于清除所述第一激光切割所述基板时产生的副产物，使得在确保高切割效率的同时，还能提高切割后的基板表面平整度。
2、本发明的晶圆切割方法，通过提供第一激光和第二激光，所述第一激光作用于所述晶圆，所述第二激光作用于所述第一激光作用在所述晶圆上的位置，且所述第二激光作用于所述晶圆上的位置的时间与所述第一激光作用 在所述晶圆上的相应位置的时间之差T大于等于0；其中，所述第一激光用于切割所述晶圆，所述第二激光用于清除所述第一激光切割所述晶圆时产生的副产物，使得在确保高切割效率的同时，还能提高切割后的晶圆表面平整度。
附图说明
图1是一种激光切割装置的示意图；
图2是本发明一实施例的激光切割装置的示意图；
图3是本发明一实施例的晶圆切割方法的流程图。
其中，附图1～图3的附图标记说明如下：
10-晶圆；11-承载台；12-激光器；20-基板；21-承载台；221-皮秒激光器；222-飞秒激光器；23-聚焦分光单元；241-第一聚焦单元；242-第二聚焦单元。
具体实施方式
为使本发明的目的、优点和特征更加清楚，以下结合附图对本发明提出的激光切割装置以及晶圆切割方法作进一步详细说明。需说明的是，附图均采用非常简化的形式且均使用非精准的比例，仅用以方便、明晰地辅助说明本发明实施例的目的。
本发明一实施例提供一种激光切割装置，用于对固定于承载台上的基板进行切割，所述激光切割装置包括：激光器，所述激光器与所述承载台之间设置有所述基板，所述激光器用于发射第一激光和第二激光，所述第一激光作用于所述基板，所述第二激光作用于所述第一激光作用在所述基板上的位置，且所述第二激光作用于所述基板上的位置的时间与所述第一激光作用在所述基板上的相应位置的时间之差T大于等于0；其中，所述第一激光用于切割所述基板，所述第二激光用于清除所述第一激光切割所述基板时产生的副产物。
下面对本实施例提供的激光切割装置进行详细介绍。
所述承载台的承载面朝向所述激光器，所述基板固定于所述承载台的承 载面上，所述基板设置于所述激光器与所述承载台之间。
所述承载台上设置有吸附部件或夹持部件，或者同时设置吸附部件和夹持部件，以通过吸附部件和/或夹持部件将所述基板固定于所述承载台上。
所述基板可以是玻璃基板、陶瓷基板、晶圆或者本领域技术人员已知的各种基板。优选地，所述基板为晶圆，所述晶圆包括衬底以及设置在所述衬底上的介质层，所述介质层中形成有导电材料。所述晶圆包括多个芯片区以及连接相邻芯片区之间的切割道，在对切割道进行切割后获得芯片。
所述第一激光的脉宽大于所述第二激光的脉宽且所述第一激光作用在所述基板上的范围小于所述第二激光作用在所述基板上的范围，以使所述第一激光用于切割所述基板、所述第二激光用于清除所述第一激光切割所述基板时产生的副产物。
激光与物质相互作用时，热效应的大小与激光的脉宽之间关系极为密切。举例来说，激光作用到材料上，能量首先被激发的电子吸收，再通过电子晶格散射的作用将能量传递给晶格，这个过程的时间尺度在几十个皮秒，之后热量在晶格之间传递，使得周围晶格温度升高，引起材料的相变焰化和气化。对于纳秒激光来说，由于其脉宽远大于电子晶格散射的时间，在脉冲作用的过程中，能量有足够的时间由电子传递给晶格，并在晶格之间扩散，使得晶格温度逐渐升高发生溶化和气化。与之所不同的是，飞秒激光器产生的脉冲，其脉宽更短，此时脉冲的作用时间远小于电子晶格散射的时间，激光脉冲作用完成时能量来不及传递给晶格，此时的晶格是“冷”的，飞秒激光引起的材料解离发生在几个皮秒的时间内。皮秒脉宽介于纳秒与飞秒的脉宽之间，皮秒激光与材料相互作用时，产生的热效应影响介于纳秒激光和飞秒激光之间。
因此，所述第一激光的脉宽大于所述基板的电子晶格散射时间，以使所述第一激光用于切割所述基板。所述第一激光切割所述基板时会在所述基板上切割出一个很深的槽，以确保高切割效率，但是，由于激光的能量很高，热效应明显，导致槽的表面以及靠近槽的基板表面会产生各种副产物，所述副产物可以是熔渣以及槽的顶部拐角处产生的卷边。
通过将所述第二激光的脉宽小于所述基板的电子晶格散射时间，使所述 第二激光基本不用于继续切割所述基板，避免副产物的继续堆积。而是通过将所述第二激光作用在所述基板的范围比所述第一激光作用在所述基板上的范围大，将槽表面以及靠近槽的基板表面的各种副产物溶化和气化，从而实现清除所述第一激光切割所述基板时产生的副产物的效果，进而能够提高切割后的基板表面平整度。
所述第一激光用于切割所述基板，所述第二激光用于清除所述第一激光切割所述基板时产生的副产物可以有多种实施方式。将所述第一激光的靠近所述基板的发射路径与所述第二激光的靠近所述基板的发射路径在水平方向上间隔距离设为L，L大于等于一预设距离，所述预设距离能够实现所述第二激光作用在所述基板上的位置可以覆盖所述第一激光作用在所述基板上的位置或者所述第二激光作用在所述基板上的位置与所述第一激光作用在所述基板上的位置有交叉。当L等于预设距离时，所述第二激光作用在所述基板上的位置覆盖所述第一激光作用在所述基板上的位置或者所述第二激光作用在所述基板上的位置与所述第一激光作用在所述基板上的位置有交叉；当L大于预设距离时，所述第二激光作用在所述基板上的位置与所述第一激光作用在所述基板上的位置既不重合也不交叉。优选地，所述第二激光作用在所述基板上的范围比所述第一激光作用在所述基板上的范围大1μm～7μm。
当所述第二激光作用于所述基板上的位置的时间与所述第一激光作用在所述基板上的相应位置的时间之差T＝0时，所述第一激光作用于所述基板的同时所述第二激光作用于所述基板上的同一位置，所述L等于预设距离，能够实现所述第一激光用于切割所述基板的同时所述第二激光用于清除所述第一激光切割所述基板时产生的副产物。
当所述第二激光作用于所述基板上的位置的时间与所述第一激光作用在所述基板上的相应位置的时间之差T＞0时，在所述第一激光作用于所述基板上后所述第二激光再作用于所述第一激光在所述基板上所作用的同一位置，所述第二激光与所述第一激光作用于所述基板上同一位置具有时间滞后，所述L可以等于预设距离也可以大于预设距离。一实施例中，所述L等于所述预设距离，所述基板上的同一位置同时位于所述第一激光与所述第二激光的 作用范围内，通过先发射所述第一激光、后发射所述第二激光实现在所述第一激光作用于所述基板上后所述第二激光再作用于所述基板上，所述第一激光与所述第二激光呈脉冲间隔交替发射，所述第一激光作用在所述基板的作用点后所述基板保持不动，在相邻两个所述第一激光的间隙发射所述第二激光，使所述第二激光作用在所述基板的作用点(所述基板上的同一位置，本实施例中对应为图1中的M点)，在该实施例中，在所述第一激光与所述第二激光依次交替作用在所述基板的作用点(M点)完成所述基板的作用点(M点)位置的切割与副产物去除后，移动所述基板进行所述基板下一位置的切割；另一实施例中，所述L大于所述预设距离，所述基板上的同一位置不同时位于所述第一激光与所述第二激光的作用范围内，通过同时发射所述第一激光、所述第二激光实现在所述第一激光作用于所述基板上后所述第二激光再作用于所述第一激光在所述基板上所作用的同一位置，所述第一激光作用在所述基板的作用点(所述基板上的同一位置，本实施例中对应为图2中的A点)后所述基板沿着背向所述基板上的下一位置(本实施例中对应为图2中的B点)的方向移动，当所述基板的作用点(A点)移动至所述第二激光作用范围时，所述第二激光清除所述第一激光切割所述基板的作用点(A点)产生的副产物。
在所述第一激光作用于所述基板上后所述第二激光再作用于所述第一激光在所述基板上所作用的同一位置，所述第一激光作用在所述基板上后所述第二激光再作用于所述基板对应为一个周期，在一个周期内所述第一激光作用所述基板的次数为x，所述第二激光作用所述基板的次数为y，所述周期重复的次数为N，其中，x≥1、y≥1、N≥1，x、y、N均为整数，重复上述周期直至切断所述基板，能够实现切割所述基板并清除基板附近的副产物，从而对基板切割槽附近的表面进行抛光，并避免切割过程中产生的副产物堆积，提高基板切割表面平整度。
一实施例中，当x＝1、y＝1、N＝1时，步骤S21：所述第一激光对所述基板作用一次切割所述基板；接着，步骤S22：所述第二激光对所述基板作用一次清除所述第一激光切割所述基板时产生的副产物，完成所述基板的切割与 副产物的清除。又一实施例中，当x＝1、y＝1、N＝2时，步骤S21：所述第一激光对所述基板作用一次切割所述基板；接着，步骤S22：所述第二激光对所述基板作用一次清除所述第一激光切割所述基板时产生的副产物；最后，将步骤S21至步骤S22循环一次完成所述基板的切割与副产物的清除。再一实施例中，当x＝2、y＝3、N＝3时，步骤S21：所述第一激光对所述基板作用2次切割所述基板；接着，步骤S22：所述第二激光对所述基板作用3次清除所述第一激光切割所述基板时产生的副产物；最后，将步骤S21至步骤S22循环三次完成所述基板的切割与副产物的清除。
优选的，所述第一激光的靠近所述基板的发射路径与所述第二激光的靠近所述基板的发射路径在水平方向上间隔距离L大于一预设距离，所述基板沿着所述基板作用点背向所述基板下一位置的方向移动，步骤S21：所述第一激光对所述基板作用x次沿着所述基板作用点背向所述基板下一位置的方向上切割所述基板；步骤S22：所述第二激光对所述基板作用y次沿着所述基板作用点背向所述基板下一位置的方向上清除所述第一激光切割所述基板时产生的副产物；将步骤S21至步骤S22循环N-1次完成所述基板的切割与副产物的清除。
所述激光器可以是一个，也可以是至少两个。所述激光器为一个时，所述一个激光器依次交替发射所述第一激光和所述第二激光，或者，所述一个激光器同时发射所述第一激光和所述第二激光。所述激光器为至少两个时，所述至少两个激光器分别用于发射所述第一激光和所述第二激光，可以是所述至少两个激光器分别用于依次交替发射所述第一激光和所述第二激光，也可以是所述至少两个激光器在水平方向上间隔一定距离同时发射所述第一激光和/或所述第二激光。
其中，所述激光器为至少两个时，所述激光器可以为纳秒激光器、皮秒激光器和飞秒激光器中的至少两个，所述纳秒激光器、所述皮秒激光器和所述飞秒激光器发射激光的脉宽依次减小。即可以采用所述纳秒激光器和所述皮秒激光器分别发射纳秒激光和皮秒激光切割所述基板，或者，采用所述纳秒激光器和所述飞秒激光器分别发射纳秒激光和飞秒激光切割所述基板并清 除副产物，或者，采用所述皮秒激光器和所述飞秒激光器分别发射皮秒激光和飞秒激光切割所述基板并清除副产物，或者，依次采用所述纳秒激光器、所述皮秒激光器和所述飞秒激光器分别发射纳秒激光、皮秒激光、飞秒激光切割所述基板并清除副产物。优选的，发射所述第一激光的激光器为皮秒激光器，发射所述第二激光的激光器为飞秒激光器。
在纳秒激光器、皮秒激光器、飞秒激光器中，由于所述纳秒激光器发射的激光脉宽最大，所述纳秒激光器发射的激光不仅能在所述基板上切割出一个很深的槽，甚至能够将所述基板完全切断；而所述皮秒激光器发射的脉宽位于所述飞秒激光器与所述纳秒激光器之间，所述皮秒激光器切割力位于所述纳秒激光器切割力与所述飞秒激光器切割力之间。因此，为使所述第一激光的脉宽大于所述基板的电子晶格散射时间而使所述第一激光用于切割所述基板，发射所述第一激光的激光器可以为纳秒激光器、皮秒激光器。
由于所述飞秒激光器发射的激光脉宽小于所述基板的电子晶格散射时间，所述飞秒激光器发射的激光作用在基板上时，基本不会使得之前激光器切割的槽的深度进一步加深，而是将槽表面和靠近槽的基板表面的熔渣以及槽顶部的卷边气化从而去除槽表面和靠近槽的基板表面的副产物，对所述基板表面的抛光效果更好，因此，优选采用飞秒激光器发射所述第二激光用于清除所述第一激光切割所述基板时产生的副产物。
所述激光切割装置还包括聚焦分光单元，设置于所述基板与所述激光器之间，所述聚焦分光单元用于调整所述第一激光的靠近所述基板的发射路径和所述第二激光的靠近所述基板的发射路径在水平方向上之间的距离。通过将所述聚焦分光单元向所述激光器的方向移动，使得所述第一激光的靠近所述基板的发射路径和所述第二激光的靠近所述基板的发射路径在水平方向上之间的距离增大；通过将所述聚焦分光单元向所述基板的方向移动，使得所述第一激光的靠近所述基板的发射路径和所述第二激光的靠近所述基板的发射路径在水平方向上之间的距离减小。
当所述激光器发射的第一激光切割导致的熔渣和卷边的量很多时，可以将所述激光器发射的第二激光的靠近所述基板的发射路径与第一激光的靠近 所述基板的发射路径在水平方向上之间的距离减小，以使得所述第二激光能够更快速的去除熔渣和卷边，避免熔渣和卷边逐渐堆积。
所述聚焦分光单元可以包括透镜以及用于固定透镜的部件。
所述激光切割装置还包括聚焦单元，设置于所述聚焦分光单元与所述激光器之间，所述聚焦单元用于将所述激光器发射的所述第一激光和所述第二激光分别聚焦在所述聚焦分光单元上；并且，所述聚焦分光单元能够对入射至所述聚焦分光单元中的所述第一激光和所述第二激光分别再次进行聚焦，以使得入射至所述基板上的所述第一激光和所述第二激光均更加集中，从而使得对所述基板进行切割的位置更加精确。
所述聚焦单元可以包括透镜以及用于固定透镜的部件。
所述第一激光和所述第二激光从所述激光器发射出来时，相互之间可以基本平行也可以不平行，经过所述聚焦分光单元的处理之后，从所述聚焦分光单元出射至所述基板上的所述第一激光和所述第二激光之间相互平行，使得所述激光器发射的所述第一激光和所述第二激光对所述基板的切割路径保持一致，避免导致切割偏移。
在图2所示的实施例中，所述承载台21上的基板20上方设置有两个所述激光器，可以分别为皮秒激光器221和飞秒激光器222，所述皮秒激光器221和所述飞秒激光器222间隔设置，所述皮秒激光器221发射的第一激光L2经所述第一聚焦单元241聚焦后入射至所述聚焦分光单元23中，并从所述聚焦分光单元23中出射至所述基板20上，所述飞秒激光器222发射的第二激光L3经所述第二聚焦单元242聚焦后入射至所述聚焦分光单元23中，并从所述聚焦分光单元23中出射至所述基板20上；且当所述基板20为晶圆时，第一激光L2与第二激光L3入射至所述基板20上的同一切割道上。第一激光L2作用于所述基板20上的作用点(A点)后第二激光L3再作用于所述基板20上的同一作用点(A点)，第一激光L2的靠近所述基板的发射路径与第二激光L3的靠近所述基板的发射路径在水平方向(X方向)上间隔距离为L，所述L大于所述预设距离，在切割的过程中，所述第一激光L2作用在所述基板20上的作用点(A点)之后，沿着X方向移动所述承载台21，使得所述 基板20沿着所述基板20作用点(A点)背向所述基板下一位置(B点)的方向移动，当所述基板20上的作用点(A点)移动至所述第二激光L3的作用范围时，所述第二激光L3清除所述第一激光L2切割所述基板20的作用点(A点)产生的副产物，从而实现第一激光L2先对所述切割道进行切割，第二激光L3沿着第一激光L2的切割路径跟随着对同一切割道进行切割。
从上述内容可知，本发明的激光切割装置，由于包括激光器，所述激光器与所述承载台之间设置有所述基板，所述激光器用于发射第一激光和第二激光，所述第一激光作用于所述基板，所述第二激光作用于所述第一激光作用在所述基板上的位置，且所述第二激光作用于所述基板上的位置与所述第一激光作用在所述基板上的位置的时间差T大于等于0；其中，所述第一激光用于切割所述基板，所述第二激光用于清除所述第一激光切割所述基板时产生的副产物，使得在确保高切割效率的同时，还能提高切割后的基板表面平整度。
本发明一实施例提供一种晶圆切割方法，参阅图3，所述晶圆切割方法包括：
步骤S1、提供一晶圆，所述晶圆固定于承载台上；
步骤S2、提供第一激光和第二激光，所述第一激光作用于所述晶圆，所述第二激光作用于所述第一激光作用在所述晶圆上的位置，且所述第二激光作用于所述晶圆上的位置的时间与所述第一激光作用在所述晶圆上的相应位置的时间之差T大于等于0；其中，所述第一激光用于切割所述晶圆，所述第二激光用于清除所述第一激光切割所述晶圆时产生的副产物。
下面对所述晶圆切割方法进行详细说明。
按照步骤S1，提供一晶圆，所述晶圆固定于承载台上。
所述承载台的承载面朝向所述激光器，所述晶圆固定于所述承载台的承载面上，所述晶圆设置于所述激光器与所述承载台之间，所述激光器的描述参见上述激光切割装置，在此不再赘述。
在切割所述晶圆的过程中，所述激光器固定不动，水平移动所述承载台，使得所述承载台在水平方向上靠近所述激光器。
所述晶圆包括衬底以及形成于所述衬底上的介质层，所述介质层中形成有导电材料。所述晶圆包括多个芯片区以及连接相邻芯片区之间的切割道，在对切割道进行切割后获得芯片。
按照步骤S2，提供第一激光和第二激光，所述第一激光作用于所述晶圆，所述第二激光作用于所述第一激光作用在所述晶圆上的位置，且所述第二激光作用于所述晶圆上的位置的时间与所述第一激光作用在所述晶圆上的相应位置的时间之差T大于等于0；其中，所述第一激光用于切割所述晶圆，所述第二激光用于清除所述第一激光切割所述晶圆时产生的副产物。
所述第一激光的脉宽大于所述第二激光的脉宽且所述第一激光作用在所述晶圆上的范围小于所述第二激光作用在所述晶圆上的范围，以使所述第一激光用于切割所述晶圆、所述第二激光用于清除所述第一激光切割所述晶圆时产生的副产物。
所述第一激光用于切割所述晶圆，所述第二激光用于清除所述第一激光切割所述晶圆时产生的副产物可以有多种实施方式。将所述第一激光的靠近所述晶圆的发射路径与所述第二激光的靠近所述晶圆的发射路径在水平方向上间隔距离设为L，L大于等于一预设距离，所述预设距离能够实现所述第二激光作用在所述晶圆上的位置可以覆盖所述第一激光作用在所述晶圆上的位置或者所述第二激光作用在所述晶圆上的位置与所述第一激光作用在所述晶圆上的位置有交叉。当L等于预设距离时，所述第二激光作用在所述晶圆上的位置覆盖所述第一激光作用在所述晶圆上的位置或者所述第二激光作用在所述晶圆上的位置与所述第一激光作用在所述晶圆上的位置有交叉；当L大于预设距离时，所述第二激光作用在所述晶圆上的位置与所述第一激光作用在所述晶圆上的位置既不重合也不交叉。优选地，所述第二激光作用在所述晶圆上的范围比所述第一激光作用在所述晶圆上的范围大1μm～7μm。
当所述第二激光作用于所述晶圆上的位置的时间与所述第一激光作用在所述晶圆上相应位置的时间之差T＝0时，所述第一激光作用于所述晶圆的同时所述第二激光作用于所述晶圆上的同一位置，所述L等于预设距离，能够实现所述第一激光用于切割所述晶圆的同时所述第二激光用于清除所述第一 激光切割所述晶圆时产生的副产物。
当所述第二激光作用于所述晶圆上的位置的时间与所述第一激光作用在所述晶圆上的相应位置的时间之差T＞0时，在所述第一激光作用于所述晶圆上后所述第二激光再作用于所述第一激光在所述晶圆上所作用的同一位置，所述第二激光与所述第一激光作用于所述晶圆上同一位置具有时间滞后，所述L可以等于预设距离也可以大于预设距离。一实施例中，所述L等于所述预设距离，所述晶圆上的同一位置同时位于所述第一激光与所述第二激光的作用范围内，通过先发射所述第一激光、后发射所述第二激光实现在所述第一激光作用于所述晶圆后所述第二激光再作用于所述晶圆上，所述第一激光与所述第二激光呈脉冲间隔交替发射，所述第一激光作用在所述晶圆的作用点后所述晶圆保持不动，在相邻两个所述第一激光的间隙发射所述第二激光，使所述第二激光作用在所述晶圆的作用点(所述晶圆上的同一位置，本实施例中对应为图1中的M点)，在该实施例中，在所述第一激光与所述第二激光依次交替作用在所述晶圆的作用点(M点)完成所述晶圆的作用点(M点)位置的切割与副产物去除后，移动所述晶圆进行所述晶圆下一位置的切割；另一实施例中，所述L大于所述预设距离，所述晶圆上的同一位置不同时位于所述第一激光与所述第二激光的作用范围内，通过同时发射所述第一激光、所述第二激光实现在所述第一激光作用在所述晶圆上后所述第二激光再作用于所述第一激光在所述晶圆上所作用的同一位置，所述第一激光作用在所述晶圆的作用点(所述晶圆上的同一位置，本实施例中对应为图2中的A点)后所述晶圆沿着背向所述晶圆上的下一位置(本实施例中对应为图2中的B点)的方向移动，当所述晶圆的作用点(A点)移动至所述第二激光作用范围时，所述第二激光清除所述第一激光切割所述晶圆的作用点(A点)产生的副产物。
在所述第一激光作用于所述晶圆后所述第二激光再作用于所述第一激光在所述晶圆上所述作用的同一位置，在相邻两个所述第二激光作用所述晶圆的间隙所述第一激光作用所述晶圆的次数为x，在相邻两个所述第一激光作用所述晶圆的间隙所述第二激光作用所述晶圆的次数为y，将所述第一激光作用 在所述晶圆上后所述第二激光再作用于所述晶圆对应为一个周期，所述周期重复的次数为N，其中，x≥1、y≥1、N≥1，x、y、N均为整数，重复上述周期直至切断所述晶圆，能够实现切割所述晶圆并清除晶圆附近的副产物，从而对晶圆切割槽附近的表面进行抛光，并避免切割过程中产生的副产物堆积，提高晶圆切割表面平整度。
一实施例中，当x＝1、y＝1、N＝1时，步骤S21：所述第一激光对所述晶圆作用一次切割所述晶圆；接着，步骤S22：所述第二激光对所述晶圆作用一次清除所述第一激光切割所述晶圆时产生的副产物，完成所述晶圆的切割与副产物的清除。又一实施例中，当x＝1、y＝1、N＝2时，步骤S21：所述第一激光对所述晶圆作用一次切割所述晶圆；接着，步骤S22：所述第二激光对所述晶圆作用一次清除所述第一激光切割所述晶圆时产生的副产物；最后，将步骤S21至步骤S22循环一次完成所述晶圆的切割与副产物的清除。再一实施例中，当x＝2、y＝3、N＝3时，步骤S21：所述第一激光对所述晶圆作用2次切割所述晶圆；接着，步骤S22：所述第二激光对所述晶圆作用3次清除所述第一激光切割所述晶圆时产生的副产物；最后，将步骤S21至步骤S22循环三次完成所述晶圆的切割与副产物的清除。
优选的，所述第一激光的靠近所述晶圆的发射路径与所述第二激光的靠近所述晶圆的发射路径在水平方向上间隔距离L大于一预设距离，所述晶圆沿着所述晶圆作用点背向所述晶圆下一位置的方向上移动，步骤S21：所述第一激光对所述晶圆作用x次沿着所述晶圆作用点背向所述晶圆下一位置的方向上切割所述晶圆；步骤S22：所述第二激光对所述晶圆作用y次沿着所述晶圆作用点背向所述晶圆下一位置的方向上清除所述第一激光切割所述晶圆时产生的副产物；将步骤S21至步骤S22循环N-1次完成所述晶圆的切割与副产物的清除。
优选的，所述第一激光为皮秒激光，所述第二激光为飞秒激光。
在纳秒激光、皮秒激光、飞秒激光中，由于所述纳秒激光脉宽最大，所述纳秒激光不仅能在所述晶圆上切割出一个很深的槽，甚至能够将所述晶圆完全切断；而所述皮秒激光的脉宽位于所述飞秒激光与所述纳秒激光之间， 所述皮秒激光切割力位于所述纳秒激光切割力与所述飞秒激光切割力之间。因此，为使所述第一激光的脉宽大于所述晶圆的电子晶格散射时间而使所述第一激光用于切割所述晶圆，所述第一激光可以为纳秒激光、皮秒激光。
由于所述飞秒激光的激光脉宽小于所述晶圆的电子晶格散射时间，所述飞秒激光作用在晶圆上时，基本不会使得之前激光切割的槽的深度进一步加深，而是将槽表面和靠近槽的晶圆表面的熔渣以及槽顶部的卷边气化从而去除槽表面和靠近槽的晶圆表面的副产物，对所述晶圆表面的抛光效果更好，因此，优选采用飞秒激光用于清除所述第一激光切割所述晶圆时产生的副产物。
在对所述晶圆的切割道进行切割时，可以先采用皮秒激光器发射的皮秒激光切割所述切割道上的介质层和导电材料，再采用飞秒激光器发射的飞秒激光对所述晶圆表面抛光处理，接着再采用干法刻蚀(例如等离子体刻蚀)或湿法刻蚀工艺切割所述切割道上的衬底；或者，先采用纳秒激光器发射的纳秒激光切断所述切割道，再采用所述飞秒激光器发射的飞秒激光对所述晶圆表面抛光处理。需要说明的是，将所述切割道完全切断的方案不仅限于上述两种，可以根据需要选择合适的切割方案。
另外，若采用先激光切割再刻蚀工艺切割的切割方案，则在切割所述切割道上的介质层和导电材料之前，所述晶圆切割方法还包括：在所述晶圆表面覆盖保护层，所述保护层用于在采用刻蚀工艺切割所述切割道上的衬底时保护所述切割道以外的区域(含芯片区)不被刻蚀。并且，所述保护层还能在激光切割时保护所述切割道以外的区域，避免激光切割产生的熔渣附着在所述切割道以外的区域上。
所述保护层的材质可以为水溶性树脂。
从上述内容可知，本发明的晶圆切割方法，通过提供第一激光和第二激光，所述第一激光作用于所述晶圆，所述第二激光作用于所述第一激光作用在所述晶圆上的位置，且所述第二激光作用于所述晶圆上的位置的时间与所述第一激光作用在所述晶圆上的位置的时间之差T大于等于0；其中，所述第一激光用于切割所述晶圆，所述第二激光用于清除所述第一激光切割所述晶 圆时产生的副产物，使得在确保高切割效率的同时，还能提高切割后的晶圆表面平整度。
上述描述仅是对本发明较佳实施例的描述，并非对本发明范围的任何限定，本发明领域的普通技术人员根据上述揭示内容做的任何变更、修饰，均属于权利要求书的保护范围。

Claims (11)

  1. 一种激光切割装置，用于对固定于承载台上的基板进行切割，其特征在于，所述激光切割装置包括：
    激光器，所述激光器与所述承载台之间设置有所述基板，所述激光器用于发射第一激光和第二激光，所述第一激光作用于所述基板，所述第二激光作用于所述第一激光作用在所述基板上的位置，且所述第二激光作用于所述基板上的一位置的时间与所述第一激光作用在所述基板上的相应位置的时间之差T大于等于0；
    其中，所述第一激光用于切割所述基板，所述第二激光用于清除所述第一激光切割所述基板时产生的副产物。
  2. 如权利要求1所述的激光切割装置，其特征在于，所述第一激光的脉宽大于所述第二激光的脉宽且所述第一激光作用在所述基板上的范围小于所述第二激光作用在所述基板上的范围，以使所述第一激光用于切割所述基板、所述第二激光用于清除所述第一激光副产物。
  3. 如权利要求2所述的激光切割装置，其特征在于，所述第二激光作用在所述基板上的范围比所述第一激光作用在所述基板上的范围大1μm～7μm。
  4. 如权利要求1所述的激光切割装置，其特征在于，包括：至少两个激光器，所述至少两个激光器分别用于发射所述第一激光和所述第二激光。
  5. 如权利要求4所述的激光切割装置，其特征在于，发射所述第一激光的激光器为皮秒激光器，发射所述第二激光的激光器为飞秒激光器。
  6. 如权利要求1所述的激光切割装置，其特征在于，所述激光切割装置还包括聚焦分光单元，设置于所述基板与所述激光器之间，所述聚焦分光单元用于调整所述第一激光的靠近所述基板的发射路径和所述第二激光的靠近所述基板的发射路径在水平方向上之间的距离。
  7. 如权利要求6所述的激光切割装置，其特征在于，所述激光切割装置还包括聚焦单元，设置于所述聚焦分光单元与所述激光器之间，所述聚焦单元用于将所述第一激光和所述第二激光聚焦在所述聚焦分光单元上。
  8. 一种晶圆切割方法，其特征在于，包括：
    提供一晶圆，所述晶圆固定于承载台上；
    提供第一激光和第二激光，所述第一激光作用于所述晶圆，所述第二激光作用于所述第一激光作用在所述晶圆上的位置，且所述第二激光作用于所述晶圆上的一位置的时间与所述第一激光作用在所述晶圆上的相应位置的时间之差T大于等于0；
    其中，所述第一激光用于切割所述晶圆，所述第二激光用于清除所述第一激光切割所述晶圆时产生的副产物。
  9. 如权利要求8所述的晶圆切割方法，其特征在于，所述第一激光的脉宽大于所述第二激光的脉宽且所述第一激光作用在所述晶圆上的范围小于所述第二激光作用在所述晶圆上的范围，以使所述第一激光用于切割所述基板、所述第二激光用于清除所述第一激光副产物。
  10. 如权利要求9所述的晶圆切割方法，其特征在于，所述第一激光为皮秒激光，所述第二激光为飞秒激光。
  11. 如权利要求8所述的晶圆切割方法，其特征在于，所述晶圆包括衬底以及形成于所述衬底上的介质层，所述介质层中形成有导电材料；采用所述第一激光和所述第二激光切割所述晶圆上的介质层和导电材料，并采用刻蚀工艺切割所述晶圆上的所述衬底。
PCT/CN2022/137439 2022-10-11 2022-12-30 激光切割装置以及晶圆切割方法 WO2024077749A1 (zh)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202211244108.6A CN115533338A (zh) 2022-10-11 2022-10-11 激光切割装置以及晶圆切割方法
CN202211244108.6 2022-10-11

Publications (1)

Publication Number Publication Date
WO2024077749A1 true WO2024077749A1 (zh) 2024-04-18

Family

ID=84734101

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2022/137439 WO2024077749A1 (zh) 2022-10-11 2022-12-30 激光切割装置以及晶圆切割方法

Country Status (3)

Country Link
CN (1) CN115533338A (zh)
TW (1) TW202416369A (zh)
WO (1) WO2024077749A1 (zh)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001219285A (ja) * 2000-02-10 2001-08-14 Nippon Steel Corp 鋼材のレーザ切断方法
CN108500468A (zh) * 2018-01-22 2018-09-07 江苏大学 一种曲线轮廓激光去毛刺的方法
WO2022004827A1 (ja) * 2020-06-30 2022-01-06 古河電気工業株式会社 金属箔のレーザ切断方法およびレーザ切断装置
CN114728378A (zh) * 2019-11-22 2022-07-08 美敦力公司 激光切割***
CN114918558A (zh) * 2022-05-27 2022-08-19 武汉新芯集成电路制造有限公司 激光切割装置以及晶圆切割方法

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001219285A (ja) * 2000-02-10 2001-08-14 Nippon Steel Corp 鋼材のレーザ切断方法
CN108500468A (zh) * 2018-01-22 2018-09-07 江苏大学 一种曲线轮廓激光去毛刺的方法
CN114728378A (zh) * 2019-11-22 2022-07-08 美敦力公司 激光切割***
WO2022004827A1 (ja) * 2020-06-30 2022-01-06 古河電気工業株式会社 金属箔のレーザ切断方法およびレーザ切断装置
CN114918558A (zh) * 2022-05-27 2022-08-19 武汉新芯集成电路制造有限公司 激光切割装置以及晶圆切割方法

Also Published As

Publication number Publication date
TW202416369A (zh) 2024-04-16
CN115533338A (zh) 2022-12-30

Similar Documents

Publication Publication Date Title
JP5607138B2 (ja) ガラス基板上のチップスケールパッケージのレーザ個別化のための方法
US10315403B2 (en) Method for cutting object to be processed
TWI508155B (zh) 使用混合式***射束雷射劃線製程及電漿蝕刻的晶圓切割
TWI536438B (zh) 多步驟且非對稱塑形的雷射束劃線
TWI422451B (zh) Laser processing method and semiconductor chip
KR101721709B1 (ko) 가공 대상물 절단 방법
TWI647758B (zh) 無遮罩混合式雷射劃線及電漿蝕刻晶圓切割製程
JP6081993B2 (ja) プラズマエッチングを伴うハイブリッドガルバニックレーザスクライビングプロセスを用いたウェハダイシング
US20140091069A1 (en) Ultrashort laser pulse wafer scribing
JP2015519732A (ja) プラズマエッチングによるハイブリッドマルチステップレーザスクライビングプロセスを用いたウェハダイシング
TWI607526B (zh) 切割包含複數個積體電路之基板的方法
JP2018523291A (ja) 半導体加工対象物のスクライブ方法
JP2005294325A (ja) 基板製造方法及び基板製造装置
JP6012185B2 (ja) 半導体デバイスの製造方法
WO2014030517A1 (ja) 加工対象物切断方法
KR102527033B1 (ko) 웨이퍼의 가공 방법
KR102270457B1 (ko) 다이 패키징 품질을 향상시키기 위한 웨이퍼 다이싱 방법
JP5969214B2 (ja) 半導体デバイスの製造方法
WO2024077749A1 (zh) 激光切割装置以及晶圆切割方法
JP2022544148A (ja) 空間的に複数の焦点を合わせるレーザビームのレーザスクライビング処理およびプラズマエッチング処理を用いるハイブリッドウエハダイシング手法
WO2017056769A1 (ja) レーザ加工方法及びレーザ加工装置
JP2020021968A (ja) 半導体加工対象物のスクライブ方法
CN109979879A (zh) 半导体芯片制造方法
JP2013157449A (ja) 半導体デバイスの製造方法
CN116984760A (zh) 激光加工碳化硅晶圆的方法及***

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 22961928

Country of ref document: EP

Kind code of ref document: A1