WO2019244460A1 - Semiconductor element forming sapphire substrate, method of manufacturing semiconductor element forming sapphire substrate, and method of transferring semiconductor element - Google Patents

Semiconductor element forming sapphire substrate, method of manufacturing semiconductor element forming sapphire substrate, and method of transferring semiconductor element Download PDF

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Publication number
WO2019244460A1
WO2019244460A1 PCT/JP2019/016277 JP2019016277W WO2019244460A1 WO 2019244460 A1 WO2019244460 A1 WO 2019244460A1 JP 2019016277 W JP2019016277 W JP 2019016277W WO 2019244460 A1 WO2019244460 A1 WO 2019244460A1
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Prior art keywords
sapphire substrate
semiconductor element
gallium
gallium nitride
nitrogen
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PCT/JP2019/016277
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French (fr)
Japanese (ja)
Inventor
良勝 柳川
貴文 平野
康一郎 深谷
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株式会社ブイ・テクノロジー
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Priority claimed from JP2018157485A external-priority patent/JP2019220666A/en
Application filed by 株式会社ブイ・テクノロジー filed Critical 株式会社ブイ・テクノロジー
Priority to US17/048,763 priority Critical patent/US20210151354A1/en
Priority to KR1020217000444A priority patent/KR20210020078A/en
Priority to CN201980041198.9A priority patent/CN112313776A/en
Publication of WO2019244460A1 publication Critical patent/WO2019244460A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • 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
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/683—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/48—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages

Definitions

  • the present invention relates to a sapphire substrate on which a semiconductor element is formed, a method for manufacturing the sapphire substrate on which a semiconductor element is formed, and the method for transferring a semiconductor element.
  • sapphire Since sapphire has a small lattice mismatch with gallium nitride, a method of manufacturing a semiconductor device by laminating a gallium nitride-based semiconductor material on a sapphire substrate is generally used. On the other hand, sapphire is inferior in thermal conductivity and conductivity, and thus is not always suitable for a manufactured semiconductor device. Therefore, a semiconductor element is peeled off from a sapphire substrate and mounted on a predetermined circuit board.
  • LLO laser lift-off
  • Laser lift-off is a method in which a gallium nitride-based semiconductor element is separated from the sapphire substrate by irradiating a laser beam from the back side of the sapphire substrate to the vicinity of the interface with the gallium nitride-based semiconductor element (for example, see Patent Document 1).
  • gallium nitride based semiconductor devices separated from a sapphire substrate are difficult to handle. Therefore, a method of transferring the semiconductor device to a circuit board after laser lifting off the semiconductor device on an adhesive film or the like is adopted. Has been.
  • the method of once laser lifting off a semiconductor element on an adhesive film or the like requires not only an adhesive film but also a device for handling the adhesive film, and has a problem that the number of manufacturing steps is increased. Further, when the adhesive film is deformed or the like, there is a problem that the semiconductor element transferred to the adhesive film is displaced, and the semiconductor element cannot be transferred to the circuit board with high accuracy.
  • a semiconductor device is provided to a user of the semiconductor device in a state of being arranged on a sapphire substrate. Therefore, when a user of a semiconductor element performs a laser lift-off, a device for handling an adhesive film and a device for performing a laser lift-off are required, and there has been a problem that the cost is increased.
  • An object of the present invention is to solve the above-described problems, and it is possible to transfer a semiconductor element to a circuit board with high accuracy, and to reduce the number of steps and equipment burden in a step of separating a semiconductor element from a sapphire substrate. It is an object of the present invention to provide a sapphire substrate on which a semiconductor element is formed, a method for manufacturing the sapphire substrate on which a semiconductor element is formed, and a method for transferring a semiconductor element.
  • a semiconductor element forming sapphire substrate is a semiconductor element forming sapphire substrate in which gallium nitride based semiconductor elements are arranged and formed on a sapphire substrate, wherein the sapphire substrate and the semiconductor A nitrogen gallium re-fusion layer is provided at the interface with the element, and the adhesive strength of the nitrogen gallium re-fusion layer is smaller than the adhesion strength of the adhesive layer for bonding the semiconductor element to the circuit board.
  • the semiconductor element forming sapphire substrate according to the present invention has the nitrogen gallium re-fusion layer at the interface between the sapphire substrate and the semiconductor element.
  • This nitrogen-gallium re-fusion layer is formed by irradiating a laser beam with an energy density smaller than the energy density of the laser beam that separates the semiconductor element from the sapphire substrate. Therefore, this nitrogen-gallium re-fusion layer is a fragile layer formed of re-solidified gallium or a part of gallium nitride that has not been ablated. Is held in a state where it does not peel off.
  • the nitrogen-gallium re-fusion layer has an adhesive strength smaller than the adhesive strength of the adhesive layer for bonding the semiconductor element to the circuit board. Therefore, the semiconductor element can be easily separated from the sapphire substrate by utilizing the adhesive force of the adhesive layer used when the semiconductor element is bonded to the circuit board. As a result, there is no need for the user of the semiconductor element to prepare an apparatus for handling the adhesive film or an apparatus for performing a laser lift-off, thereby reducing the man-hour and equipment burden in the step of separating the semiconductor element from the sapphire substrate. Can be.
  • the semiconductor element of the sapphire substrate can be directly transferred to the circuit board without using an adhesive film or the like, and high-accuracy transfer can be performed.
  • the adhesive strength of the nitrogen gallium re-fusion layer at the interface between the sapphire substrate and the semiconductor element is 230 kg / cm 2 or less in shear strength.
  • used when bonding the semiconductor element via an adhesive layer on said circuit board, for adhesion of typical adhesive layers, depending on the type of adhesive is approximately 100kg / cm 2 ⁇ 400kg / cm 2
  • the semiconductor element can be separated from the sapphire substrate.
  • the shear strength of the nitrogen-gallium re-fused layer only needs to be smaller than the adhesive strength of the adhesive layer as described above, and more preferably less than 100 kg / cm 2 .
  • a method for manufacturing a semiconductor element forming sapphire substrate according to the present invention which has been made to solve the above problem, forms a gallium nitride based semiconductor element on a sapphire substrate, and then peels off the semiconductor element from the sapphire substrate.
  • a pre-peeling process is performed, wherein the pre-peeling process is performed by irradiating a laser beam from a back surface side of the sapphire substrate to an interface between the semiconductor element and the sapphire substrate.
  • the laser light in the step is irradiated with a laser element at an energy density smaller than the energy density of the laser light peeling the semiconductor element from the sapphire substrate, after the laser light irradiation,
  • the sapphire substrate and the semiconductor element are connected to the It is characterized by a small adhesive strength than the adhesive strength of the adhesive layer for bonding, and is held in.
  • the energy density at the interface between the semiconductor element and the sapphire substrate is smaller than the energy density of the laser light at which the semiconductor element is separated from the sapphire substrate.
  • the nitrogen-gallium re-fusion layer can be easily formed.
  • the adhesive strength of the nitrogen-gallium re-fusion layer is smaller than the adhesive strength of the adhesive layer for bonding the semiconductor element to the circuit board, the adhesive layer used for bonding the semiconductor element to the circuit board to be formed thereafter is not used. The semiconductor element can be easily separated from the sapphire substrate by the adhesive force.
  • the sapphire substrate and the semiconductor element are held by a nitrogen gallium re-fusion layer having a shear strength of 230 kg / cm 2 or less.
  • the laser light is irradiated a plurality of times to each of the gallium nitride-based semiconductor elements.
  • the semiconductor element may be separated from the sapphire substrate. Therefore, it is desirable to reduce the energy density of the laser light and irradiate the laser light a plurality of times.
  • a method for manufacturing a semiconductor element-formed sapphire substrate according to the present invention which has been made to solve the above-described problem, is a method for manufacturing a semiconductor element-formed sapphire substrate in which a gallium nitride-based semiconductor element is formed on a sapphire substrate.
  • the gallium nitride based semiconductor device After the formation of the gallium nitride based semiconductor device, including a pre-peeling process for peeling the semiconductor device from the sapphire substrate, the pre-peeling process, the interface between the gallium nitride based semiconductor device and the sapphire substrate.
  • the gallium nitride based semiconductor device irradiates a laser beam having an energy density smaller than the energy density of the laser beam peeled from the sapphire substrate a plurality of times from the back side of the sapphire substrate.
  • the semiconductor element is not separated from the sapphire substrate by irradiating the laser light having an energy density smaller than the energy density of the laser light from which the gallium nitride based semiconductor element is separated from the sapphire substrate a plurality of times from the back surface side of the sapphire substrate. Even so, processing for facilitating separation of the semiconductor element from the sapphire substrate can be performed.
  • the laser beam is irradiated from the back surface side of the sapphire substrate while applying pressure between the gallium nitride based semiconductor device and the sapphire substrate.
  • the conditions (process margin) for forming a nitrogen-gallium re-fusion layer in the pre-peeling treatment process are increased. is there.
  • an interface region between the gallium nitride-based semiconductor element and the sapphire substrate may be divided into a plurality of regions, and the laser light may be irradiated from a back surface side of the sapphire substrate.
  • a method of irradiating a laser beam by dividing an interface region between a semiconductor element and a sapphire substrate into a plurality of parts has the same effect as irradiating a laser beam while applying pressure between a semiconductor element and a sapphire substrate.
  • the laser beam is applied to the sapphire through a projection mask designed to irradiate an area smaller than an interface area between the gallium nitride based semiconductor device and the sapphire substrate. Irradiation is preferably performed from the back side of the substrate.
  • a method for transferring a semiconductor element from a sapphire substrate is directed to a method for manufacturing a sapphire substrate for forming a semiconductor element or a semiconductor element formed by the method for manufacturing a sapphire substrate for forming a semiconductor element.
  • the safing process is performed by the bonding step of bonding through the bonding layer and the bonding force of the bonding layer.
  • separating the semiconductor element from A substrate is characterized in that it comprises a peeling-arranging step of arranging the semiconductor element to the circuit board.
  • the semiconductor element can be easily separated from the sapphire substrate by bonding the semiconductor element to the circuit board via an adhesive layer. Can be. Moreover, the purchaser of the semiconductor element does not need to prepare an apparatus for handling the adhesive film or an apparatus for performing a laser lift-off, which can reduce the number of steps and equipment burden in the step of peeling the semiconductor element from the sapphire substrate. it can. In addition, since the semiconductor element can be directly transferred to the circuit board without using an adhesive film or the like, high-accuracy transfer can be performed.
  • a semiconductor element forming sapphire substrate, and a semiconductor element forming semiconductor device capable of transferring a semiconductor element onto a circuit substrate with high precision and reducing the number of steps and equipment burden in a step of separating the semiconductor element from the sapphire substrate
  • the method for manufacturing a formed sapphire substrate and the method for transferring a semiconductor element can be obtained.
  • FIG. 1 is a schematic sectional view showing a sapphire substrate on which a semiconductor element is formed according to the present invention.
  • FIG. 2 is a schematic configuration diagram showing an example of an apparatus configuration for performing the method for manufacturing a sapphire substrate on which a semiconductor element is formed according to the present invention.
  • FIG. 3 is a plan view showing a semiconductor device formed on a sapphire substrate.
  • FIG. 4 is a side view of FIG.
  • FIG. 5 is a flowchart showing the steps of a method for manufacturing a sapphire substrate on which a semiconductor element is formed and a method for transferring a semiconductor element according to the present invention.
  • FIG. 6 is a schematic configuration diagram for explaining the process of step S2 in FIG. FIG.
  • FIG. 7 is a schematic configuration diagram for explaining the process of step S3 in FIG.
  • FIG. 8 is a schematic configuration diagram for explaining the process of step S4 in FIG.
  • FIG. 9 is a schematic configuration diagram for explaining the process of step S5 in FIG.
  • FIG. 10 is a diagram showing the relationship between the energy density and the number of irradiations (the number of shots) of laser light and the conditions under which the semiconductor element is separated from the sapphire substrate.
  • FIG. 11 is a diagram exemplifying a method of using a transparent plate such as quartz glass as a method of applying pressure between a semiconductor element and a sapphire substrate.
  • FIG. 12 is a diagram illustrating a method of using an adhesive film as a method of applying pressure between a semiconductor element and a sapphire substrate.
  • FIG. 13 shows the energy density and the number of shots (the number of shots) of the laser beam when the laser beam is irradiated from the back surface side of the sapphire substrate while pressing the semiconductor device and the sapphire substrate, and the semiconductor device is separated from the sapphire substrate. It is a figure showing the relation with a condition.
  • FIG. 14 is a diagram illustrating a method of irradiating a laser beam by dividing an interface region between a semiconductor element and a sapphire substrate into a plurality of regions.
  • FIG. 15 is a diagram illustrating a method of irradiating a laser beam by dividing an interface region between a semiconductor element and a sapphire substrate into a plurality.
  • a sapphire substrate 12 on which a semiconductor element is formed has a gallium nitride-based semiconductor element 10 arrayed on a sapphire substrate 11.
  • a method for forming the gallium nitride based semiconductor element 10 on the sapphire substrate 11 a generally known method can be used.
  • a gallium nitride based light emitting diode can be cited.
  • a semiconductor element 10 made of a gallium nitride-based semiconductor material such as a light emitting diode (LED)
  • a sapphire substrate 11 having a small lattice mismatch with gallium nitride is preferably used.
  • the gallium nitride-based semiconductor material is not limited to pure gallium nitride, and may be a semiconductor material containing a small amount of aluminum or indium, which is the same Group III element as gallium.
  • the gallium nitride-based light-emitting diodes are formed and arranged in a matrix on the main surface of the sapphire substrate 11, as shown in FIGS. Is about 20 to about 80 ⁇ m, and the thickness is about several ⁇ m to about 10 ⁇ m.
  • a nitrogen-gallium re-fusion layer A is formed between the sapphire substrate 11 and the semiconductor element 10 (interface).
  • This nitrogen-gallium re-fusion layer A applies laser light from the back side of the sapphire substrate 11 to the interface between the semiconductor element 10 and the sapphire substrate 11, as will be described in detail later in the method for manufacturing a sapphire substrate for forming a semiconductor element. It is formed by irradiation. At this time, the energy density of the laser light is smaller than the energy density of the laser light that ablates gallium nitride and peels off the semiconductor element 10 from the sapphire substrate 11.
  • gallium nitride is decomposed into gallium and nitrogen even when irradiated with a laser beam having a low energy density. Is presumed to be composed of gallium that has subsequently been resolidified or some gallium nitride that has not been ablated. Then, the semiconductor element 10 of the semiconductor element formation sapphire substrate 12 on which the nitrogen gallium re-fusion layer A is formed is held on the sapphire substrate 11 without being separated from the sapphire substrate 11.
  • the sapphire substrate 11 and the semiconductor element 10 are connected by a nitrogen gallium re-fusion layer having a shear strength of 230 kg / cm 2 or less.
  • the adhesive strength of the common adhesive layer (shear strength), depending on the type of adhesive, is approximately 100kg / cm 2 ⁇ 400kg / cm 2 .
  • the shear strength of the nitrogen-gallium re-fusion layer is 230 kg / cm 2 or less, which is smaller than the bonding strength of the bonding layer for bonding the semiconductor element to the circuit board, it is used when bonding the semiconductor element to the circuit board.
  • the semiconductor element can be easily separated from the sapphire substrate by the adhesive force of the adhesive layer obtained.
  • the shear strength of the nitrogen-gallium re-fused layer only needs to be smaller than the adhesive strength of the adhesive layer as described above, and more preferably less than 100 kg / cm 2 .
  • FIG. 2 is a diagram showing an example of an apparatus configuration for performing the method for manufacturing a sapphire substrate on which a semiconductor element is formed according to the present invention.
  • the apparatus shown in FIG. 2 is not particularly limited.
  • an apparatus (laser processing apparatus) 100 for performing the method of manufacturing a sapphire substrate on which a semiconductor element is formed includes a laser head 110, a uniform optical system 120, a microscope unit 130, a processing stage 140, and a control unit 150.
  • the laser head 110 for example, one that outputs a picosecond laser having a wavelength of 263 nm (FHG) with a pulse width of 10 psec can be used.
  • the uniform optical system 120 is for making the laser light output from the laser head 110 have a uniform intensity distribution, and includes a beam expanding lens 121, a homogenizer 122, and a condenser lens 123.
  • the beam expanding lens 121 expands the beam diameter of the laser light output from the laser head 110
  • the homogenizer 122 uniforms the intensity distribution of the laser light having the expanded beam diameter.
  • the condenser lens 123 again narrows the beam diameter of the laser light, so that the laser light output from the laser head 110 can have a uniform intensity distribution as a whole.
  • the microscope section 130 is for irradiating the laser light output from the laser head 110 to the processing target W at an appropriate energy density.
  • the microscope unit 130 includes an objective lens 131 and a projection mask 132, and is configured to focus laser light having a desired shape by the projection mask 132 onto a processing target W on a processing stage 140 by the objective lens 131. Have been.
  • As the processing stage 140 it is preferable to use a so-called XY ⁇ stage that can move horizontally in the vertical and horizontal directions and in the rotation direction.
  • control unit 150 links the intensity and timing of the laser beam output from the laser head 110 with the movement of the processing target W performed by the processing stage 140.
  • the control unit 150 includes a laser power supply / control unit 151, a stage control unit 152, and a control computer 153.
  • the laser power supply / control unit 151 controls the output of the laser head 110, and the stage control unit 152
  • the movement is controlled, and the control computer 153 is configured to control the laser power supply / control unit 151 and the stage control unit 152.
  • the intensity and timing of the laser beam output from the laser head 110 can be linked with the movement of the processing target W performed by the processing stage 140.
  • FIG. 3 and 4 are views showing an example of a semiconductor element formed on a sapphire substrate by a general method.
  • FIG. 3 is a plan view
  • FIG. 4 is a side view.
  • the semiconductor element 10 is formed by crystal growth on a sapphire substrate 11, and as a substantial extension of the sapphire crystal lattice in the sapphire substrate 11, a semiconductor element is formed by growing a gallium nitride-based semiconductor material crystal.
  • the gallium nitride-based semiconductor material may be not only pure gallium nitride but also a semiconductor material containing a small amount of aluminum or indium, which is the same Group III element as gallium.
  • FIGS. 3 and 4 generally, a plurality of semiconductor elements 10 are formed on one sapphire substrate 11. Further, an electrode 13 necessary for the following description is provided on the semiconductor element 10 (see FIG. 1). The other detailed configuration of the semiconductor element 10 is not described because it does not affect the embodiment of the present invention.
  • a sapphire substrate 11 on which the semiconductor elements 10 are arranged and formed on the sapphire substrate 11 shown in FIGS. 3 and 4 is prepared (step S1 in FIG. 5).
  • a nitrogen gallium re-fusion layer forming step for separating the substrate 11 from the semiconductor element 10 is performed (step S2 in FIG. 5).
  • This pre-processing step (Step S2) is performed using the above-described laser processing apparatus 100 (see FIG. 2).
  • FIG. 6 shows the state of the sapphire substrate on which the semiconductor element is formed in step S2.
  • the interface between the semiconductor element 10 and the sapphire substrate 11 is irradiated with laser light L from the back side of the sapphire substrate 11, thereby forming the nitrogen-gallium re-fusion layer A.
  • the laser light is applied at an energy density smaller than the energy density of the laser light L that separates the semiconductor element from the sapphire substrate.
  • the energy density smaller than the energy density of the laser beam that separates the semiconductor element from the sapphire substrate means that the energy density is lower than the energy density used in general conventional laser lift-off.
  • the energy density used in the laser lift-off is generally 150 mJ / cm 2
  • the energy density of the laser beam L applied in step S2 is less than 150 mJ / cm 2 .
  • gallium nitride near the interface with the substrate 11 irradiated with a laser beam having a high energy density is decomposed into gallium and nitrogen, and gasified nitrogen is dissipated, so that the interface with the substrate 11 is reduced. Peels off.
  • the laser beam having a small energy density applied in step S2 the laser beam is not of such an extent that gallium nitride is decomposed into gallium and nitrogen and gasified nitrogen is dissipated.
  • the element 10 is re-fused (the nitrogen-gallium re-fused layer A is formed at the interface between the sapphire substrate 11 and the semiconductor element 10).
  • a part of the gallium nitride that has not been ablated remains at the interface between the sapphire substrate 11 and the semiconductor element 10 (a nitrogen gallium re-fusion layer A is formed).
  • the shear strength (adhesion strength) at the interface between the substrate 11 and the semiconductor element 10 is smaller than the adhesion strength when the semiconductor element 10 is bonded to the circuit board in a later step.
  • the nitrogen gallium re-fusion layer A has a shear strength of 230 kg / cm 2 or less.
  • the laser beam L irradiated in step S2 is applied to each semiconductor element 10 a plurality of times, and the number of times of irradiation is 10 or more times for each semiconductor element 10. preferable. More preferably, it is 10 to 20 times.
  • the energy density of the irradiated laser beam is not necessarily constant, so that the energy density is divided into a plurality of times to offset the variation and to prevent the semiconductor element 10 from exceeding the energy density at which the semiconductor element 10 is separated from the substrate 11.
  • step S2 corresponds to the method for manufacturing a sapphire substrate on which a semiconductor element is formed according to the embodiment of the present invention.
  • the sapphire substrate on which a semiconductor element is formed according to the embodiment of the present invention is manufactured Is done.
  • FIG. 1 An embodiment according to a semiconductor element transfer method of the present invention will be described with reference to FIGS. 5, 7, 8, and 9.
  • FIG. 1 a sapphire substrate on which a semiconductor element is formed on which the above-mentioned nitrogen gallium re-fusion layer A is formed is prepared.
  • an adhesive layer having a greater shear strength (adhesive strength) than the shear strength (adhesive strength) of the nitrogen-gallium re-fusion layer A is formed on a semiconductor element on the sapphire substrate or a circuit board, though not shown. .
  • the semiconductor element forming sapphire substrate 12 on which the nitrogen-gallium re-fusion layer A is formed is transported under the circuit board 14 (see FIG. 5), and the semiconductors arranged on the substrate 11 as shown in FIG. The element 10 is aligned with the circuit board 14 (Step S3 in FIG. 5).
  • an electrode 15 is provided on the circuit board 14.
  • the electrode 15 is for electrically connecting to the electrode 13 provided on the semiconductor element 10. Therefore, unless the electrodes 15 of the circuit board 14 and the electrodes 13 of the semiconductor element 10 are properly aligned, the semiconductor element 10 cannot be properly conducted.
  • the semiconductor element formation sapphire substrate 12 shown in FIG. 7 is in a state where the semiconductor element 10 is held on the sapphire substrate 11 via the nitrogen gallium re-fusion layer A. Therefore, the semiconductor element 10 can be positioned with respect to the circuit board 14 while maintaining high positional accuracy during the manufacture of the semiconductor element 10. Furthermore, as compared with the conventional method of transferring the semiconductor element 10 to the adhesive film and then positioning the semiconductor element 10 on the circuit board 14, the positioning accuracy in Step S3 is extremely high.
  • the semiconductor element 10 is bonded to the circuit board 14 while pressing the semiconductor element forming sapphire substrate 12 against the circuit board 14 (Step S4 in FIG. 5).
  • a known method is used so that the semiconductor element 10 is fixed to the circuit board 14 while securing electrical connection between the electrode 15 of the circuit board 14 and the electrode 13 of the semiconductor element 10. Then, the semiconductor element 10 is bonded to the circuit board 14 via the bonding layer.
  • the adhesive constituting the adhesive layer a general photosensitive adhesive can be used.
  • the adhesive force of the adhesive (shear strength), depending on the type of adhesive is approximately 100kg / cm 2 ⁇ 400kg / cm 2.
  • a peeling step of peeling the sapphire substrate 11 from the semiconductor element 10 (Step S5 in FIG. 5) is performed.
  • the semiconductor element 10 is peeled from the sapphire substrate 11 using the adhesive strength of the semiconductor element 10 to the circuit board 14 (the adhesive strength of the adhesive layer).
  • the bonding strength (share strength) between the sapphire substrate 11 and the semiconductor element 10 by the nitrogen-gallium re-fusion layer A is determined by the bonding strength (share strength) of the bonding layer that bonds the semiconductor element 10 to the circuit board 14.
  • the semiconductor element 10 is peeled from the sapphire substrate 11 by peeling the sapphire substrate 11 from the circuit board 14. That is, the semiconductor element 10 is transferred (transferred) from the sapphire substrate 11 to the circuit substrate 14.
  • the method of transferring a semiconductor element does not include a conventional step of irradiating a laser beam for peeling a semiconductor element. Therefore, the user of the semiconductor device can transfer (transfer) the semiconductor device 10 from the sapphire substrate 11 to the circuit substrate 14 with high accuracy without using a laser beam irradiation device.
  • the pre-processing step (Step S2) is for facilitating peeling of the semiconductor element 10 from the sapphire substrate 11 after the formation of the semiconductor element 10,
  • the interface is irradiated with laser light having an energy density smaller than the energy density of the laser light peeled from the sapphire substrate 11 by the semiconductor element 10 a plurality of times from the back surface side of the sapphire substrate 11.
  • FIG. 4 is a diagram showing the relationship between the energy density of laser light, the number of irradiations (the number of shots), and the conditions under which the semiconductor element peels off from the sapphire substrate.
  • the state of the interface between the semiconductor element 10 and the sapphire substrate 11 after irradiating the interface between the semiconductor element 10 and the sapphire substrate 11 with laser light from the back side of the sapphire substrate 11 can be roughly divided. It can be divided into three states. That is, the state in which the close contact state between the semiconductor element 10 and the sapphire substrate 11 does not change even after the laser light irradiation (area (a)), and the state in which the semiconductor element 10 peels off from the sapphire substrate 11 after the laser light irradiation.
  • region (b) There is a state (region (b)) and a state (region (c)) in which a nitrogen gallium re-fusion layer is formed between the semiconductor element 10 and the sapphire substrate 11 after the laser beam irradiation.
  • a nitrogen gallium re-fusion layer is formed between the semiconductor element 10 and the sapphire substrate 11 after the laser beam irradiation.
  • the specific composition of the nitrogen-gallium re-fusion layer is not clear here, even in the case of laser light with a low energy density, some gallium nitride is decomposed into gallium and nitrogen, It is presumed that some of the nitrogen released is dissipated. Therefore, it is presumed that gallium solidified alone or part of gallium nitride not ablated remains in the nitrogen gallium re-fusion layer.
  • the conditions (process margin) under which the nitrogen-gallium re-fused layer can be formed in the pretreatment step (step S2) are narrow.
  • the energy density of the irradiated laser beam is lower than E1
  • the adhesion state between the semiconductor element 10 and the sapphire substrate 11 does not change, and a desired nitrogen gallium re-fusion layer cannot be formed.
  • the energy density of the irradiated laser beam is higher than E3, the semiconductor element 10 is separated from the sapphire substrate 11. Further, even if the energy density of the laser light to be irradiated is lower than E3, the nitrogen-gallium re-fusion layer cannot be formed unless the number of laser light irradiations (the number of shots) is at least n1.
  • step S2 the following measures may be taken.
  • One is a method of irradiating a laser beam from the back surface side of the sapphire substrate 11 while applying pressure between the semiconductor device 10 and the sapphire substrate 11, and the other is a method of irradiating the interface between the semiconductor device 10 and the sapphire substrate 11.
  • This is a method in which a region is divided into a plurality of regions and a laser beam is irradiated from the back side of the sapphire substrate 11.
  • a method of irradiating a laser beam from the back side of the sapphire substrate 11 while applying pressure between the semiconductor element 10 and the sapphire substrate 11 for example, a method using a transparent plate such as quartz glass as shown in FIG. As shown in the above, a method using an adhesive film can be adopted.
  • the sapphire substrate 11 is placed on the processing stage 140 with the semiconductor element 10 facing the processing stage 140, and the sapphire substrate is The laser beam is irradiated while pressing 11 on the processing stage 140.
  • a laser beam is applied from the back side of the sapphire substrate 11 with the elastic adhesive film 17 attached to the surface of the sapphire substrate 11 on which the semiconductor element 10 is formed. Irradiate.
  • the semiconductor element 10 is irradiated with laser light from the back side of the sapphire substrate 11 in a state where the semiconductor element 10 is pressed against the sapphire substrate 11 by the elasticity of the adhesive film 17. .
  • FIG. 13 shows the energy density and the number of irradiations (the number of shots) of the laser beam when the laser beam is irradiated from the back side of the sapphire substrate 11 while applying pressure between the semiconductor element 10 and the sapphire substrate 11 according to the method described above.
  • FIG. 4 is a diagram showing the relationship between the condition (1) and the condition under which the semiconductor element is separated from the sapphire substrate. As can be understood from a comparison between FIG. 13 and FIG. 10, when the laser beam is irradiated from the back surface side of the sapphire substrate 11 while applying pressure between the semiconductor element 10 and the sapphire substrate 11, the entire graph spreads in the vertical direction.
  • the energy density of the irradiated laser light is higher when the pressure is applied than when the pressure is not applied. Specifically, the energy density of E1 rises to E1 ', the energy density of E2 rises to E2', and the energy density of E3 rises to E3 '. I have.
  • the process margin when performing the pre-processing step (step S2) without applying pressure has an energy density of 50 to 60 mJ / cm 2 and the number of shots is 20 or more
  • the semiconductor element 10 and the sapphire substrate 11 When the laser light is irradiated from the back side of the sapphire substrate 11 while the pressure is increased, the process margin is increased to an energy density of 60 to 100 mJ / cm 2 and the number of shots is increased to 20 or more.
  • the pressure between the semiconductor element 10 and the sapphire substrate 11 is pressurized by using a separate jig or component, but the area of the interface between the semiconductor element and the sapphire substrate shown in FIGS. Even in the method of irradiating the laser light in a plurality of parts, substantially the same effect as pressurizing can be obtained. Therefore, a method for irradiating a laser beam by dividing an interface region between a semiconductor element and a sapphire substrate into a plurality of regions will be described with reference to FIGS.
  • FIG. 14 schematically shows a state in which the interface between the semiconductor element 10 and the sapphire substrate 11 is observed through the sapphire substrate 11.
  • the region of the interface between the semiconductor element 10 and the sapphire substrate 11 is divided into a plurality of regions, and laser light is irradiated from the back surface side of the sapphire substrate 11.
  • the irradiation area L of the laser beam is set to be narrower than the area of the interface between the semiconductor element 10 and the sapphire substrate 11, and the semiconductor element 10 and the sapphire substrate 11 are divided into two times. The entire area of the interface between them is processed.
  • step S2 it is assumed that the laser light is irradiated a plurality of times. However, when the region is divided into a plurality of regions, each region is irradiated with the laser light a plurality of times.
  • FIG. 15 schematically shows a state where the interface between the semiconductor element 10 and the sapphire substrate 11 is observed through the sapphire substrate 11.
  • the region of the interface between the semiconductor element 10 and the sapphire substrate 11 is divided into a plurality of stripes, and the laser light in the stripe-shaped irradiation region L is irradiated from the back side of the sapphire substrate 11. While moving in the direction of the arrow in the figure. Even if such an irradiation method is used, the region of the interface between the semiconductor element 10 and the sapphire substrate 11 is divided into a plurality of regions, and each region is irradiated with laser light a plurality of times.
  • a projection mask designed to irradiate a region smaller than the region at the interface between the semiconductor element 10 and the sapphire substrate 11 is required. It is preferable to irradiate the laser beam through the interface.
  • the laser light in the irradiation region L smaller than the region of the interface between the semiconductor element 10 and the sapphire substrate 11 is irradiated, a region not irradiated with the laser light always remains. The close contact state between them is maintained without change. Therefore, the adhesion force in the area where the close contact state is maintained exerts a pressurizing action on the area where the laser beam is irradiated and the processing is in progress.
  • the method of irradiating the laser light by dividing the region of the interface between the semiconductor element 10 and the sapphire substrate 11 into a plurality of parts has the same effect as that of irradiating the laser light while applying pressure between the semiconductor element 10 and the sapphire substrate 11. Will be played.
  • the gallium nitride-based semiconductor device is described by taking a gallium nitride-based light emitting diode as an example, but the present invention is not limited to this.

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Abstract

The present invention makes it possible to transfer a semiconductor element to a circuit board with high accuracy and reduce man-hours and facility burden in a step of releasing the semiconductor element from a sapphire substrate. The present invention is a semiconductor element forming sapphire substrate 12 on which gallium nitride-based semiconductor elements are arranged on the sapphire substrate 12, and is characterized in that a gallium nitride re-fusing layer A is provided at an interface between the sapphire substrate 11 and the semiconductor elements 10 and the gallium nitride re-fusing layer has adhesive strength that is smaller than the adhesive strength of an adhesive layer that adheres the semiconductor elements to a circuit board.

Description

半導体素子形成サファイア基板、及び前記半導体素子形成サファイア基板の製造方法、並びに前記半導体素子の転写方法Sapphire substrate on which semiconductor element is formed, method for manufacturing the sapphire substrate on which semiconductor element is formed, and method for transferring the semiconductor element
　本発明は、半導体素子形成サファイア基板、及び前記半導体素子形成サファイア基板の製造方法、並びに前記半導体素子転写方法に関する。 The present invention relates to a sapphire substrate on which a semiconductor element is formed, a method for manufacturing the sapphire substrate on which a semiconductor element is formed, and the method for transferring a semiconductor element.
　サファイアは窒化ガリウムとの格子不整合が小さいので、サファイア基板上に窒化ガリウム系の半導体材料を積層して半導体素子を製造する方法が一般によく用いられている。
　一方、サファイアは熱伝導性や導電性に劣るので、製造後の半導体素子にとっては必ずしも好適とは言えない。そのため、半導体素子をサファイア基板から剥離し、所定の回路基板に装着することが行われている。 Since sapphire has a small lattice mismatch with gallium nitride, a method of manufacturing a semiconductor device by laminating a gallium nitride-based semiconductor material on a sapphire substrate is generally used.
On the other hand, sapphire is inferior in thermal conductivity and conductivity, and thus is not always suitable for a manufactured semiconductor device. Therefore, a semiconductor element is peeled off from a sapphire substrate and mounted on a predetermined circuit board.
　このサファイア基板から窒化ガリウム系半導体素子を剥離する方法として、従来からレーザリフトオフ（ＬＬＯ）が知られている。
　レーザリフトオフとは、サファイア基板の裏側から窒化ガリウム系半導体素子との界面付近にレーザ光を照射することで、サファイア基板から窒化ガリウム系半導体素子を剥離する方法である（例えば特許文献１参照）。
　通常、サファイア基板から分離された状態の窒化ガリウム系半導体素子は、取扱いが困難なため、粘着フィルム等の上に半導体素子をレーザリフトオフした後に、当該半導体素子を回路基板に転写するという方法が取られている。 As a method for separating the gallium nitride based semiconductor element from the sapphire substrate, laser lift-off (LLO) has been conventionally known.
Laser lift-off is a method in which a gallium nitride-based semiconductor element is separated from the sapphire substrate by irradiating a laser beam from the back side of the sapphire substrate to the vicinity of the interface with the gallium nitride-based semiconductor element (for example, see Patent Document 1).
Usually, gallium nitride based semiconductor devices separated from a sapphire substrate are difficult to handle. Therefore, a method of transferring the semiconductor device to a circuit board after laser lifting off the semiconductor device on an adhesive film or the like is adopted. Has been.
特開２００２－１８２５８０号公報JP-A-2002-182580
　しかしながら、粘着フィルム等の上に半導体素子を一旦レーザリフトオフする方法は、粘着フィルムが必要なだけでなく、粘着フィルムを取り扱うための装置を必要とし、製造工程も増大するという課題があった。
　また、粘着フィルムに変形等が生じると、粘着フィルムに転写された半導体素子に位置ずれが生じ、半導体素子を回路基板に高精度に転写できないという課題があった。 However, the method of once laser lifting off a semiconductor element on an adhesive film or the like requires not only an adhesive film but also a device for handling the adhesive film, and has a problem that the number of manufacturing steps is increased.
Further, when the adhesive film is deformed or the like, there is a problem that the semiconductor element transferred to the adhesive film is displaced, and the semiconductor element cannot be transferred to the circuit board with high accuracy.
　更に、一般的に、半導体素子はサファイア基板に配置された状態で、半導体素子の利用者に提供される。そのため、半導体素子の利用者が、レーザリフトオフを行う場合には、粘着フィルムを取り扱うための装置やレーザリフトオフを行うための装置が必要となり、そのためのコストが嵩むという課題があった。 Furthermore, in general, a semiconductor device is provided to a user of the semiconductor device in a state of being arranged on a sapphire substrate. Therefore, when a user of a semiconductor element performs a laser lift-off, a device for handling an adhesive film and a device for performing a laser lift-off are required, and there has been a problem that the cost is increased.
　本発明は、上記課題を解決することを目的とするものであり、半導体素子を回路基板に高精度に転写でき、またサファイア基板から半導体素子を剥離する工程における工数および設備負担を軽減することができる、半導体素子形成サファイア基板、及び前記半導体素子形成サファイア基板の製造方法、並びに前記半導体素子転写方法を提供することを目的とする。 SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems, and it is possible to transfer a semiconductor element to a circuit board with high accuracy, and to reduce the number of steps and equipment burden in a step of separating a semiconductor element from a sapphire substrate. It is an object of the present invention to provide a sapphire substrate on which a semiconductor element is formed, a method for manufacturing the sapphire substrate on which a semiconductor element is formed, and a method for transferring a semiconductor element.
　上記課題を解決するためになされた、本発明にかかる半導体素子形成サファイア基板は、窒化ガリウム系半導体素子がサファイア基板上に配列形成された半導体素子形成サファイア基板であって、前記サファイア基板と前記半導体素子との界面に窒素ガリウム再融着層を有し、前記窒素ガリウム再融着層の接着強度が、前記半導体素子を回路基板に接着する接着層の接着強度よりも小さいことを特徴としている。 In order to solve the above problems, a semiconductor element forming sapphire substrate according to the present invention is a semiconductor element forming sapphire substrate in which gallium nitride based semiconductor elements are arranged and formed on a sapphire substrate, wherein the sapphire substrate and the semiconductor A nitrogen gallium re-fusion layer is provided at the interface with the element, and the adhesive strength of the nitrogen gallium re-fusion layer is smaller than the adhesion strength of the adhesive layer for bonding the semiconductor element to the circuit board.
　このように、本発明にかかる半導体素子形成サファイア基板は、サファイア基板と前記半導体素子との界面に窒素ガリウム再融着層を有している。
　この窒素ガリウム再融着層は、半導体素子がサファイア基板から剥離するレーザ光のエネルギー密度よりも小さなエネルギー密度で、レーザ光を照射することによって形成される。そのため、この窒素ガリウム再融着層は、再凝固したガリウム、あるいはアブレーションしなかった一部の窒化ガリウムで形成された脆弱な層であって、この窒素ガリウム再融着層によりサファイア基板から半導体素子が剥離しない状態で保持される。 As described above, the semiconductor element forming sapphire substrate according to the present invention has the nitrogen gallium re-fusion layer at the interface between the sapphire substrate and the semiconductor element.
This nitrogen-gallium re-fusion layer is formed by irradiating a laser beam with an energy density smaller than the energy density of the laser beam that separates the semiconductor element from the sapphire substrate. Therefore, this nitrogen-gallium re-fusion layer is a fragile layer formed of re-solidified gallium or a part of gallium nitride that has not been ablated. Is held in a state where it does not peel off.
　更に、前記窒素ガリウム再融着層は、半導体素子を回路基板に接着する接着層の接着強度よりも小さな接着強度を有している。そのため、回路基板に半導体素子を接着する際に用いられる接着層の接着力を利用して、サファイア基板から前記半導体素子を容易に剥離することができる。
　その結果、半導体素子の利用者が、粘着フィルムを取り扱うための装置やレーザリフトオフを行うための装置を用意する必要がなく、サファイア基板から半導体素子を剥離する工程における工数および設備負担を軽減することができる。また、粘着フィルム等を介することなく、サファイア基板の半導体素子を回路基板に直接転写することができ、高精度の転写を行うことができる。 Further, the nitrogen-gallium re-fusion layer has an adhesive strength smaller than the adhesive strength of the adhesive layer for bonding the semiconductor element to the circuit board. Therefore, the semiconductor element can be easily separated from the sapphire substrate by utilizing the adhesive force of the adhesive layer used when the semiconductor element is bonded to the circuit board.
As a result, there is no need for the user of the semiconductor element to prepare an apparatus for handling the adhesive film or an apparatus for performing a laser lift-off, thereby reducing the man-hour and equipment burden in the step of separating the semiconductor element from the sapphire substrate. Can be. In addition, the semiconductor element of the sapphire substrate can be directly transferred to the circuit board without using an adhesive film or the like, and high-accuracy transfer can be performed.
　ここで、前記サファイア基板と前記半導体素子の界面の窒素ガリウム再融着層の接着強度が、シェア強度で２３０ｋｇ／ｃｍ２以下であることが望ましい。
　半導体素子を前記回路基板に接着層を介して接着する際用いられる、一般的な接着層の接着力は、接着剤の種類にもよるが、おおよそ１００ｋｇ／ｃｍ２～４００ｋｇ／ｃｍ２であるため、一般的な接着層を用いることにより、サファイア基板から半導体素子を剥離することができる。
　また、窒素ガリウム再融着層のシェア強度は、前記したように接着層の接着力よりも小さければ良く、１００ｋｇ／ｃｍ２未満であれば更に良い。 Here, it is preferable that the adhesive strength of the nitrogen gallium re-fusion layer at the interface between the sapphire substrate and the semiconductor element is 230 kg / cm 2 or less in shear strength.
Used when bonding the semiconductor element via an adhesive layer on said circuit board, for adhesion of typical adhesive layers, depending on the type of adhesive is approximately 100kg / cm 2 ~ 400kg / cm 2 By using a general adhesive layer, the semiconductor element can be separated from the sapphire substrate.
Further, the shear strength of the nitrogen-gallium re-fused layer only needs to be smaller than the adhesive strength of the adhesive layer as described above, and more preferably less than 100 kg / cm 2 .
　また、上記課題を解決するためになされた、本発明にかかる半導体素子形成サファイア基板の製造方法は、窒化ガリウム系半導体素子をサファイア基板上に形成し、その後、前記半導体素子をサファイア基板から剥離するための剥離前処理がなされる半導体素子形成サファイア基板の製造方法において、前記剥離前処理には、半導体素子とサファイア基板の界面に対して、前記サファイア基板の裏面側からレーザ光を照射し、窒素ガリウム再融着層を形成する工程を含み、前記工程におけるレーザ光は、半導体素子が前記サファイア基板から剥離するレーザ光のエネルギー密度よりも小さいエネルギー密度で照射されることにより、レーザ光照射後、前記窒素ガリウム再融着層により、サファイア基板と半導体素子が、半導体素子を回路基板に接着する接着層の接着強度よりも小さい接着強度で、保持されていることを特徴としている。 Further, a method for manufacturing a semiconductor element forming sapphire substrate according to the present invention, which has been made to solve the above problem, forms a gallium nitride based semiconductor element on a sapphire substrate, and then peels off the semiconductor element from the sapphire substrate. In the method for manufacturing a sapphire substrate formed with a semiconductor element, a pre-peeling process is performed, wherein the pre-peeling process is performed by irradiating a laser beam from a back surface side of the sapphire substrate to an interface between the semiconductor element and the sapphire substrate. Including a step of forming a gallium re-fusion layer, the laser light in the step is irradiated with a laser element at an energy density smaller than the energy density of the laser light peeling the semiconductor element from the sapphire substrate, after the laser light irradiation, The sapphire substrate and the semiconductor element are connected to the It is characterized by a small adhesive strength than the adhesive strength of the adhesive layer for bonding, and is held in.
　このように、本発明にかかる半導体素子形成サファイア基板の製造方法によれば、半導体素子とサファイア基板の界面に対して、半導体素子が前記サファイア基板から剥離するレーザ光のエネルギー密度よりも小さいエネルギー密度で、レーザ光を照射することにより、窒素ガリウム再融着層を容易に形成することができる。
　しかも、窒素ガリウム再融着層の接着強度が、半導体素子を回路基板に接着する接着層の接着強度よりも小さいため、その後になされる回路基板に半導体素子を接着する際に用いられる接着層の接着力によって、サファイア基板から半導体素子を容易に剥離することができる。 As described above, according to the method for manufacturing a sapphire substrate on which a semiconductor element is formed according to the present invention, the energy density at the interface between the semiconductor element and the sapphire substrate is smaller than the energy density of the laser light at which the semiconductor element is separated from the sapphire substrate. By irradiating a laser beam, the nitrogen-gallium re-fusion layer can be easily formed.
In addition, since the adhesive strength of the nitrogen-gallium re-fusion layer is smaller than the adhesive strength of the adhesive layer for bonding the semiconductor element to the circuit board, the adhesive layer used for bonding the semiconductor element to the circuit board to be formed thereafter is not used. The semiconductor element can be easily separated from the sapphire substrate by the adhesive force.
　ここで、サファイア基板と半導体素子が、シェア強度で２３０ｋｇ／ｃｍ２以下の窒素ガリウム再融着層で保持されることが望ましい。
　また、前記窒素ガリウム再融着層を形成する工程における前記レーザ光の照射は、前記窒化ガリウム系半導体素子の各々に対して複数回の照射されることが望ましい。
　このように、レーザ光のエネルギー密度にはばらつきがあるため、一度の照射で接続層を形成すると、サファイア基板から半導体素子が剥離するおそれがある。そのため、レーザ光のエネルギー密度を小さくし、複数回照射するのが望ましい。 Here, it is desirable that the sapphire substrate and the semiconductor element are held by a nitrogen gallium re-fusion layer having a shear strength of 230 kg / cm 2 or less.
In the step of forming the nitrogen-gallium re-fusion layer, it is preferable that the laser light is irradiated a plurality of times to each of the gallium nitride-based semiconductor elements.
As described above, since the energy density of the laser beam varies, when the connection layer is formed by one irradiation, the semiconductor element may be separated from the sapphire substrate. Therefore, it is desirable to reduce the energy density of the laser light and irradiate the laser light a plurality of times.
　また、上記課題を解決するためになされた、本発明にかかる半導体素子形成サファイア基板の製造方法は、窒化ガリウム系半導体素子がサファイア基板上に形成された半導体素子形成サファイア基板の製造方法において、前記窒化ガリウム系半導体素子の形成後になされる、前記半導体素子をサファイア基板から剥離するための剥離前処理工程を含み、　前記剥離前処理工程では、前記窒化ガリウム系半導体素子と前記サファイア基板の界面に対して、前記窒化ガリウム系半導体素子が前記サファイア基板から剥離するレーザ光のエネルギー密度よりも小さいエネルギー密度のレーザ光を前記サファイア基板の裏面側から複数回照射する、ことを特徴としている。
　このように、窒化ガリウム系半導体素子がサファイア基板から剥離するレーザ光のエネルギー密度よりも小さいエネルギー密度のレーザ光をサファイア基板の裏面側から複数回照射することで、サファイア基板から半導体素子が剥離しないまでも、半導体素子をサファイア基板から剥離するのを容易にする加工を施すことができる。 Further, a method for manufacturing a semiconductor element-formed sapphire substrate according to the present invention, which has been made to solve the above-described problem, is a method for manufacturing a semiconductor element-formed sapphire substrate in which a gallium nitride-based semiconductor element is formed on a sapphire substrate. After the formation of the gallium nitride based semiconductor device, including a pre-peeling process for peeling the semiconductor device from the sapphire substrate, the pre-peeling process, the interface between the gallium nitride based semiconductor device and the sapphire substrate In addition, the gallium nitride based semiconductor device irradiates a laser beam having an energy density smaller than the energy density of the laser beam peeled from the sapphire substrate a plurality of times from the back side of the sapphire substrate.
As described above, the semiconductor element is not separated from the sapphire substrate by irradiating the laser light having an energy density smaller than the energy density of the laser light from which the gallium nitride based semiconductor element is separated from the sapphire substrate a plurality of times from the back surface side of the sapphire substrate. Even so, processing for facilitating separation of the semiconductor element from the sapphire substrate can be performed.
　ここで、前記剥離前処理工程では、前記窒化ガリウム系半導体素子と前記サファイア基板の間を加圧させながら、前記レーザ光を前記サファイア基板の裏面側から照射することが好ましい。
　半導体素子とサファイア基板の間を加圧させながらレーザ光をサファイア基板の裏面側から照射する場合、剥離前処理工程にて窒素ガリウム再融着層を形成し得る条件（プロセスマージン）が広がるからである。 Here, in the pre-peeling treatment step, it is preferable that the laser beam is irradiated from the back surface side of the sapphire substrate while applying pressure between the gallium nitride based semiconductor device and the sapphire substrate.
When irradiating laser light from the back side of the sapphire substrate while applying pressure between the semiconductor element and the sapphire substrate, the conditions (process margin) for forming a nitrogen-gallium re-fusion layer in the pre-peeling treatment process are increased. is there.
　また、前記剥離前処理工程では、前記窒化ガリウム系半導体素子と前記サファイア基板の界面の領域を複数に分けて、前記レーザ光を前記サファイア基板の裏面側から照射するとしてもよい。
　半導体素子とサファイア基板の界面の領域を複数に分けて、レーザ光を照射する方法は、半導体素子とサファイア基板の間を加圧させながらレーザ光照射するのと同様の効果を奏する。
　尚、このような照射方法のためには、前記窒化ガリウム系半導体素子と前記サファイア基板の界面の領域よりも小さい領域を照射するように設計された投影マスクを介して、前記レーザ光を前記サファイア基板の裏面側から照射するのが好ましい。 Further, in the pre-peeling treatment step, an interface region between the gallium nitride-based semiconductor element and the sapphire substrate may be divided into a plurality of regions, and the laser light may be irradiated from a back surface side of the sapphire substrate.
A method of irradiating a laser beam by dividing an interface region between a semiconductor element and a sapphire substrate into a plurality of parts has the same effect as irradiating a laser beam while applying pressure between a semiconductor element and a sapphire substrate.
Note that, for such an irradiation method, the laser beam is applied to the sapphire through a projection mask designed to irradiate an area smaller than an interface area between the gallium nitride based semiconductor device and the sapphire substrate. Irradiation is preferably performed from the back side of the substrate.
　また、上記課題を解決するためになされた、本発明にかかるサファイア基板からの半導体素子転写方法は、上記半導体素子形成サファイア基板、または上記半導体素子形成サファイア基板の製造方法により製造された半導体素子形成サファイア基板を用意する工程と、前記サファイア基板と前記半導体素子の界面の窒素ガリウム再融着層の接着強度よりも大きな接着強度を有する接着層を、前記サファイア基板上の半導体素子あるいは回路基板に形成する工程と、前記サファイア基板上に配列された半導体素子を、回路基板に対して位置合わせする位置合わせ工程と、前記サファイア基板を回路基板に対して押圧しながら、半導体素子を前記回路基板に、前記接着層を介して接着する接着工程と、前記接着層の接着力によって、前記サファイア基板から前記半導体素子を剥離し、前記回路基板に前記半導体素子を配置する剥離・配置工程と、を含むことを特徴としている。 Further, a method for transferring a semiconductor element from a sapphire substrate according to the present invention, which has been made to solve the above-mentioned problems, is directed to a method for manufacturing a sapphire substrate for forming a semiconductor element or a semiconductor element formed by the method for manufacturing a sapphire substrate for forming a semiconductor element. A step of preparing a sapphire substrate, and forming an adhesive layer having an adhesive strength larger than the adhesive strength of the nitrogen gallium re-fusion layer at the interface between the sapphire substrate and the semiconductor element on the semiconductor element or the circuit board on the sapphire substrate. And a positioning step of positioning the semiconductor elements arranged on the sapphire substrate with respect to a circuit board, and pressing the sapphire substrate against the circuit board while placing the semiconductor elements on the circuit board. The safing process is performed by the bonding step of bonding through the bonding layer and the bonding force of the bonding layer. And separating the semiconductor element from A substrate is characterized in that it comprises a peeling-arranging step of arranging the semiconductor element to the circuit board.
　このように、本発明にかかるサファイア基板からの半導体素子転写方法によれば、半導体素子を前記回路基板に、接着層を介して接着することにより、サファイア基板から前記半導体素子を容易に剥離することができる。
　しかも、半導体素子の購入者は、粘着フィルムを取り扱うための装置やレーザリフトオフを行うための装置を用意する必要がなく、サファイア基板から半導体素子を剥離する工程における工数および設備負担を軽減することができる。また、粘着フィルム等を介することなく、半導体素子を回路基板に直接転写することができるため、高精度の転写を行うことができる。 As described above, according to the method for transferring a semiconductor element from a sapphire substrate according to the present invention, the semiconductor element can be easily separated from the sapphire substrate by bonding the semiconductor element to the circuit board via an adhesive layer. Can be.
Moreover, the purchaser of the semiconductor element does not need to prepare an apparatus for handling the adhesive film or an apparatus for performing a laser lift-off, which can reduce the number of steps and equipment burden in the step of peeling the semiconductor element from the sapphire substrate. it can. In addition, since the semiconductor element can be directly transferred to the circuit board without using an adhesive film or the like, high-accuracy transfer can be performed.
　本発明によれば、半導体素子を回路基板に高精度に転写でき、またサファイア基板から半導体素子を剥離する工程における工数および設備負担を軽減することができる、半導体素子形成サファイア基板、及び前記半導体素子形成サファイア基板の製造方法、並びに前記半導体素子転写方法を得ることができる。 According to the present invention, a semiconductor element forming sapphire substrate, and a semiconductor element forming semiconductor device capable of transferring a semiconductor element onto a circuit substrate with high precision and reducing the number of steps and equipment burden in a step of separating the semiconductor element from the sapphire substrate The method for manufacturing a formed sapphire substrate and the method for transferring a semiconductor element can be obtained.
図１は、本発明にかかる半導体素子形成サファイア基板を示す概略断面図である。FIG. 1 is a schematic sectional view showing a sapphire substrate on which a semiconductor element is formed according to the present invention. 図２は、本発明にかかる半導体素子形成サファイア基板の製造方法を実施するための装置構成の一例を示す概略構成図である。FIG. 2 is a schematic configuration diagram showing an example of an apparatus configuration for performing the method for manufacturing a sapphire substrate on which a semiconductor element is formed according to the present invention. 図３は、サファイア基板上に形成された半導体素子を示す平面図である。FIG. 3 is a plan view showing a semiconductor device formed on a sapphire substrate. 図４は、図３の側面図である。FIG. 4 is a side view of FIG. 図５は、本発明にかかる半導体素子形成サファイア基板の製造方法、及び半導体素子の転写方法の手順を示すフローチャートである。FIG. 5 is a flowchart showing the steps of a method for manufacturing a sapphire substrate on which a semiconductor element is formed and a method for transferring a semiconductor element according to the present invention. 図６は、図５のステップＳ２の工程を説明するための概略構成図である。FIG. 6 is a schematic configuration diagram for explaining the process of step S2 in FIG. 図７は、図５のステップＳ３の工程を説明するための概略構成図である。FIG. 7 is a schematic configuration diagram for explaining the process of step S3 in FIG. 図８は、図５のステップＳ４の工程を説明するための概略構成図である。FIG. 8 is a schematic configuration diagram for explaining the process of step S4 in FIG. 図９は、図５のステップＳ５の工程を説明するための概略構成図である。FIG. 9 is a schematic configuration diagram for explaining the process of step S5 in FIG. 図１０は、レーザ光のエネルギー密度および照射回数（ショット数）と半導体素子がサファイア基板から剥離する条件との関係を示す図である。FIG. 10 is a diagram showing the relationship between the energy density and the number of irradiations (the number of shots) of laser light and the conditions under which the semiconductor element is separated from the sapphire substrate. 図１１は、半導体素子とサファイア基板の間を加圧する方法として、石英ガラス等の透明板を用いる方法を例示する図である。FIG. 11 is a diagram exemplifying a method of using a transparent plate such as quartz glass as a method of applying pressure between a semiconductor element and a sapphire substrate. 図１２は、半導体素子とサファイア基板の間を加圧する方法として、粘着フィルムを用いる方法を例示する図である。FIG. 12 is a diagram illustrating a method of using an adhesive film as a method of applying pressure between a semiconductor element and a sapphire substrate. 図１３は、半導体素子とサファイア基板の間を加圧させながらレーザ光をサファイア基板の裏面側から照射する場合のレーザ光のエネルギー密度および照射回数（ショット数）と半導体素子がサファイア基板から剥離する条件との関係を示す図である。FIG. 13 shows the energy density and the number of shots (the number of shots) of the laser beam when the laser beam is irradiated from the back surface side of the sapphire substrate while pressing the semiconductor device and the sapphire substrate, and the semiconductor device is separated from the sapphire substrate. It is a figure showing the relation with a condition. 図１４は、半導体素子とサファイア基板の界面の領域を複数に分けてレーザ光を照射する方法を示す図である。FIG. 14 is a diagram illustrating a method of irradiating a laser beam by dividing an interface region between a semiconductor element and a sapphire substrate into a plurality of regions. 図１５は、半導体素子とサファイア基板の界面の領域を複数に分けてレーザ光を照射する方法を示す図である。FIG. 15 is a diagram illustrating a method of irradiating a laser beam by dividing an interface region between a semiconductor element and a sapphire substrate into a plurality.
　まず、本発明の半導体素子形成サファイア基板にかかる実施形態について、図１に基づいて説明する。
　図１に示すように、半導体素子形成サファイア基板１２は、サファイア基板上１１に窒化ガリウム系半導体素子１０が配列形成されている。サファイア基板上１１に窒化ガリウム系半導体素子１０を形成する方法については、一般的に知られている方法を用いることができる。 First, an embodiment of a sapphire substrate on which a semiconductor element is formed according to the present invention will be described with reference to FIG.
As shown in FIG. 1, a sapphire substrate 12 on which a semiconductor element is formed has a gallium nitride-based semiconductor element 10 arrayed on a sapphire substrate 11. As a method for forming the gallium nitride based semiconductor element 10 on the sapphire substrate 11, a generally known method can be used.
　この半導体素子としては、例えば、窒化ガリウム系の発光ダイオード（ＬＥＤ）をあげることができる。例えば発光ダイオード（ＬＥＤ）など、窒化ガリウム系の半導体材料で製造される半導体素子１０の場合、窒化ガリウムとの格子不整合が小さいサファイアの基板１１が好適に用いられる。
　尚、窒化ガリウム系の半導体材料とは、純粋な窒化ガリウムだけではなく、ガリウムと同じIII族元素であるアルミニウムやインジウムを少量含む半導体材料であってもよい。
　この窒化ガリウム系発光ダイオード（ＬＥＤ）は、例えば、図３、図４に示すように、サファイア基板上１１の主面上にマトリクス状に形成、配置されており、半導体素子１０の一つの大きさは約２０乃至約８０μｍ、厚さは数μｍ乃至約１０μｍ程度である。 As this semiconductor element, for example, a gallium nitride based light emitting diode (LED) can be cited. For example, in the case of a semiconductor element 10 made of a gallium nitride-based semiconductor material such as a light emitting diode (LED), a sapphire substrate 11 having a small lattice mismatch with gallium nitride is preferably used.
Note that the gallium nitride-based semiconductor material is not limited to pure gallium nitride, and may be a semiconductor material containing a small amount of aluminum or indium, which is the same Group III element as gallium.
The gallium nitride-based light-emitting diodes (LEDs) are formed and arranged in a matrix on the main surface of the sapphire substrate 11, as shown in FIGS. Is about 20 to about 80 μm, and the thickness is about several μm to about 10 μm.
　また、図１に示すように、サファイア基板１１と前記半導体素子１０との間（界面）には、窒素ガリウム再融着層Ａが形成されている。
　この窒素ガリウム再融着層Ａは、後の半導体素子形成サファイア基板の製造方法で詳述するように、半導体素子１０とサファイア基板１１の界面に対して、サファイア基板１１の裏面側からレーザ光を照射することによって形成される。このときのレーザ光のエネルギー密度は、窒化ガリウムがアブレーションし、半導体素子１０がサファイア基板１１から剥離するレーザ光のエネルギー密度よりも小さい。 Further, as shown in FIG. 1, a nitrogen-gallium re-fusion layer A is formed between the sapphire substrate 11 and the semiconductor element 10 (interface).
This nitrogen-gallium re-fusion layer A applies laser light from the back side of the sapphire substrate 11 to the interface between the semiconductor element 10 and the sapphire substrate 11, as will be described in detail later in the method for manufacturing a sapphire substrate for forming a semiconductor element. It is formed by irradiation. At this time, the energy density of the laser light is smaller than the energy density of the laser light that ablates gallium nitride and peels off the semiconductor element 10 from the sapphire substrate 11.
　また、前記窒素ガリウム再融着層Ａの組成は定かではないが、エネルギー密度が小さいレーザ光を照射した場合にも、窒化ガリウムはガリウムと窒素に分解するため、前記窒素ガリウム再融着層Ａは、その後再凝固したガリウム、あるいはアブレーションしなかった一部の窒化ガリウムで構成されると推察される。
　そして、この窒素ガリウム再融着層Ａが形成された半導体素子形成サファイア基板１２の半導体素子１０は、サファイア基板１１から剥離しない状態で、サファイア基板１１に保持される。 Although the composition of the nitrogen gallium re-fusion layer A is not known, gallium nitride is decomposed into gallium and nitrogen even when irradiated with a laser beam having a low energy density. Is presumed to be composed of gallium that has subsequently been resolidified or some gallium nitride that has not been ablated.
Then, the semiconductor element 10 of the semiconductor element formation sapphire substrate 12 on which the nitrogen gallium re-fusion layer A is formed is held on the sapphire substrate 11 without being separated from the sapphire substrate 11.
　具体的には、シェア強度で２３０ｋｇ／ｃｍ２以下の窒素ガリウム再融着層で、サファイア基板１１と半導体素子１０は接続されている。 Specifically, the sapphire substrate 11 and the semiconductor element 10 are connected by a nitrogen gallium re-fusion layer having a shear strength of 230 kg / cm 2 or less.
　一方、半導体素子１０を回路基板に接着する際用いられる、一般的な接着層の接着力（シェア強度）は、接着剤の種類にもよるが、おおよそ１００ｋｇ／ｃｍ２～４００ｋｇ／ｃｍ２である。 On the other hand, is used when bonding the semiconductor element 10 to the circuit board, the adhesive strength of the common adhesive layer (shear strength), depending on the type of adhesive, is approximately 100kg / cm 2 ~ 400kg / cm 2 .
　したがって、窒素ガリウム再融着層のシェア強度が、半導体素子を回路基板に接着する接着層の接着強度よりも小さい、２３０ｋｇ／ｃｍ２以下であるため、回路基板に半導体素子を接着する際に用いられる接着層の接着力によって、前記サファイア基板から前記半導体素子を容易に剥離することができる。また、窒素ガリウム再融着層のシェア強度は、前記したように接着層の接着力よりも小さければ良く、１００ｋｇ／ｃｍ２未満であれば更に良い。 Therefore, since the shear strength of the nitrogen-gallium re-fusion layer is 230 kg / cm 2 or less, which is smaller than the bonding strength of the bonding layer for bonding the semiconductor element to the circuit board, it is used when bonding the semiconductor element to the circuit board. The semiconductor element can be easily separated from the sapphire substrate by the adhesive force of the adhesive layer obtained. Further, the shear strength of the nitrogen-gallium re-fused layer only needs to be smaller than the adhesive strength of the adhesive layer as described above, and more preferably less than 100 kg / cm 2 .
（半導体素子形成サファイア基板の製造方法）
本発明の半導体素子形成サファイア基板の製造方法にかかる実施形態について、図２乃至図６に基づいて説明する。 (Method of manufacturing sapphire substrate on which semiconductor element is formed)
An embodiment according to a method for manufacturing a sapphire substrate on which a semiconductor element is formed according to the present invention will be described with reference to FIGS.
　まず、本発明の半導体素子形成サファイア基板の製造方法を実施するための装置について、図２に基づいて説明する。尚、図２は、本発明の半導体素子形成サファイア基板の製造方法を実施するための装置構成の一例を示す図であり、本発明の半導体素子形成サファイア基板の製造方法を実施するための装置は、図２に示された装置に、特に限定されるものではない。 First, an apparatus for performing the method for manufacturing a sapphire substrate on which a semiconductor element is formed according to the present invention will be described with reference to FIG. FIG. 2 is a diagram showing an example of an apparatus configuration for performing the method for manufacturing a sapphire substrate on which a semiconductor element is formed according to the present invention. The apparatus shown in FIG. 2 is not particularly limited.
　図２に示されるように、半導体素子形成サファイア基板の製造方法を実施するための装置（レーザ加工装置）１００は、レーザヘッド１１０と均一光学系１２０と顕微鏡部１３０と加工ステージ１４０と制御部１５０とを備えている。
　前記レーザヘッド１１０としては、例えば波長が２６３ｎｍ（ＦＨＧ）のピコ秒レーザをパルス幅が１０ｐｓｅｃで出力するものを用いることができる。 As shown in FIG. 2, an apparatus (laser processing apparatus) 100 for performing the method of manufacturing a sapphire substrate on which a semiconductor element is formed includes a laser head 110, a uniform optical system 120, a microscope unit 130, a processing stage 140, and a control unit 150. And
As the laser head 110, for example, one that outputs a picosecond laser having a wavelength of 263 nm (FHG) with a pulse width of 10 psec can be used.
　また、前記均一光学系１２０は、レーザヘッド１１０が出力したレーザ光を均一な強度分布にするためのものであり、ビーム拡大レンズ１２１とホモジナイザ１２２とコンデンサレンズ１２３とを備えている。
　前記ビーム拡大レンズ１２１は、レーザヘッド１１０が出力したレーザ光のビーム径を拡大し、ホモジナイザ１２２はビーム径が拡大されたレーザ光の強度分布を均一化するものである。
　そして、前記コンデンサレンズ１２３がレーザ光のビーム径を再び絞ることで、全体としてレーザヘッド１１０が出力したレーザ光を均一な強度分布にすることができる。 The uniform optical system 120 is for making the laser light output from the laser head 110 have a uniform intensity distribution, and includes a beam expanding lens 121, a homogenizer 122, and a condenser lens 123.
The beam expanding lens 121 expands the beam diameter of the laser light output from the laser head 110, and the homogenizer 122 uniforms the intensity distribution of the laser light having the expanded beam diameter.
Then, the condenser lens 123 again narrows the beam diameter of the laser light, so that the laser light output from the laser head 110 can have a uniform intensity distribution as a whole.
　前記顕微鏡部１３０は、レーザヘッド１１０が出力したレーザ光を適切なエネルギー密度で加工対象Ｗに照射するためのものである。
　前記顕微鏡部１３０は、対物レンズ１３１や投影マスク１３２を備えており、投影マスク１３２によって所望の形状にしたレーザ光を、対物レンズ１３１によって加工ステージ１４０上の加工対象Ｗに集光するように構成されている。
　前記加工ステージ１４０は、水平の上下左右方向と回転方向の移動が可能な、いわゆるＸＹθステージを用いることが好ましい。 The microscope section 130 is for irradiating the laser light output from the laser head 110 to the processing target W at an appropriate energy density.
The microscope unit 130 includes an objective lens 131 and a projection mask 132, and is configured to focus laser light having a desired shape by the projection mask 132 onto a processing target W on a processing stage 140 by the objective lens 131. Have been.
As the processing stage 140, it is preferable to use a so-called XYθ stage that can move horizontally in the vertical and horizontal directions and in the rotation direction.
　また、前記制御部１５０は、レーザヘッド１１０が出力するレーザ光の強度およびタイミングと加工ステージ１４０によって行う加工対象Ｗの移動を連動させるものである。
　前記制御部１５０は、レーザ電源・制御部１５１とステージ制御部１５２と制御コンピュータ１５３とを備え、レーザ電源・制御部１５１がレーザヘッド１１０の出力を制御し、ステージ制御部１５２が加工ステージ１４０の移動を制御し、制御コンピュータ１５３がレーザ電源・制御部１５１およびステージ制御部１５２を制御するように構成されている。
　これにより、レーザヘッド１１０が出力するレーザ光の強度およびタイミングと、加工ステージ１４０によって行う加工対象Ｗの移動とを連動させることができる。 Further, the control unit 150 links the intensity and timing of the laser beam output from the laser head 110 with the movement of the processing target W performed by the processing stage 140.
The control unit 150 includes a laser power supply / control unit 151, a stage control unit 152, and a control computer 153. The laser power supply / control unit 151 controls the output of the laser head 110, and the stage control unit 152 The movement is controlled, and the control computer 153 is configured to control the laser power supply / control unit 151 and the stage control unit 152.
Thereby, the intensity and timing of the laser beam output from the laser head 110 can be linked with the movement of the processing target W performed by the processing stage 140.
　次に、半導体素子形成サファイア基板の製造方法について、図３乃至図６に基づいて説明する。 Next, a method for manufacturing a sapphire substrate on which a semiconductor element is formed will be described with reference to FIGS.
　図３および図４は、一般的な方法により、サファイア基板上に形成された半導体素子の例を示す図であって、図３は平面図、図４は側面図である。
　この半導体素子１０はサファイア基板１１の上に結晶成長によって形成され、サファイア基板１１におけるサファイアの結晶格子の実質的な延長として、窒化ガリウム系半導体材料の結晶が成長することによって、半導体素子が形成される。
　尚、既に述べたように、窒化ガリウム系の半導体材料とは、純粋な窒化ガリウムだけではなく、ガリウムと同じIII族元素であるアルミニウムやインジウムを少量含む半導体材料であってもよい。 3 and 4 are views showing an example of a semiconductor element formed on a sapphire substrate by a general method. FIG. 3 is a plan view, and FIG. 4 is a side view.
The semiconductor element 10 is formed by crystal growth on a sapphire substrate 11, and as a substantial extension of the sapphire crystal lattice in the sapphire substrate 11, a semiconductor element is formed by growing a gallium nitride-based semiconductor material crystal. You.
As described above, the gallium nitride-based semiconductor material may be not only pure gallium nitride but also a semiconductor material containing a small amount of aluminum or indium, which is the same Group III element as gallium.
　図３および図４に示されるように、一般的に、半導体素子１０は一枚のサファイア基板１１上に複数形成されている。また、後の説明との関係で必要となる電極１３が半導体素子１０には設けられている（図１参照）。
　尚、その他の半導体素子１０の詳細な構成は、発明の実施に影響しないので省略する。 As shown in FIGS. 3 and 4, generally, a plurality of semiconductor elements 10 are formed on one sapphire substrate 11. Further, an electrode 13 necessary for the following description is provided on the semiconductor element 10 (see FIG. 1).
The other detailed configuration of the semiconductor element 10 is not described because it does not affect the embodiment of the present invention.
　このようにして形成された、図３，４に示すサファイア基板１１上に半導体素子１０が配列形成された半導体素子形成サファイア基板１１を用意する（図５のステップＳ１）。 (4) A sapphire substrate 11 on which the semiconductor elements 10 are arranged and formed on the sapphire substrate 11 shown in FIGS. 3 and 4 is prepared (step S1 in FIG. 5).
　次に、図６に示すように、半導体素子１０から基板１１を剥離するための窒素ガリウム再融着層形成工程（前処理工程）を行う（図５のステップＳ２）。
　この前処理工程（ステップＳ２）は、前記したレーザ加工装置１００（図２参照）を用いて実施される。尚、図６は、このステップＳ２における半導体素子形成サファイア基板の状態を示している。 Next, as shown in FIG. 6, a nitrogen gallium re-fusion layer forming step (pre-treatment step) for separating the substrate 11 from the semiconductor element 10 is performed (step S2 in FIG. 5).
This pre-processing step (Step S2) is performed using the above-described laser processing apparatus 100 (see FIG. 2). FIG. 6 shows the state of the sapphire substrate on which the semiconductor element is formed in step S2.
　このステップＳ２では、半導体素子１０とサファイア基板１１の界面に対して、前記サファイア基板１１の裏面側からレーザ光Ｌを照射することにより、窒素ガリウム再融着層Ａが形成される。
　このとき、レーザ光は、半導体素子が前記サファイア基板から剥離するレーザ光Ｌのエネルギー密度よりも小さいエネルギー密度で照射される。 In this step S2, the interface between the semiconductor element 10 and the sapphire substrate 11 is irradiated with laser light L from the back side of the sapphire substrate 11, thereby forming the nitrogen-gallium re-fusion layer A.
At this time, the laser light is applied at an energy density smaller than the energy density of the laser light L that separates the semiconductor element from the sapphire substrate.
　前記した半導体素子が前記サファイア基板から剥離するレーザ光のエネルギー密度よりも小さいエネルギー密度とは、一般的な従前のレーザリフトオフにて用いられるエネルギー密度よりも低いエネルギー密度という意味である。
　例えば、レーザリフトオフにて用いられるエネルギー密度が、一般的に１５０ｍＪ／ｃｍ２であるのに対し、このステップＳ２にて照射されるレーザ光Ｌのエネルギー密度は、１５０ｍＪ／ｃｍ２未満である。 The energy density smaller than the energy density of the laser beam that separates the semiconductor element from the sapphire substrate means that the energy density is lower than the energy density used in general conventional laser lift-off.
For example, the energy density used in the laser lift-off is generally 150 mJ / cm 2 , whereas the energy density of the laser beam L applied in step S2 is less than 150 mJ / cm 2 .
　一般的な従前のレーザリフトオフでは、高エネルギー密度のレーザ光が照射された基板１１との界面付近の窒化ガリウムがガリウムと窒素に分解され、気体化した窒素が消散することで基板１１との界面が剥離する。
　一方で、このステップＳ２にて照射されるエネルギー密度の小さいレーザ光の場合には、窒化ガリウムをガリウムと窒素に分解し、気体化した窒素を消散させる程度のものではなく、サファイア基板１１と半導体素子１０とを再融着させる（サファイア基板１１と半導体素子１０との界面に窒素ガリウム再融着層Ａが形成される）と推察される。あるいはまた、サファイア基板１１と半導体素子１０との界面に、アブレーションしなかった窒化ガリウムの一部が残存する（窒素ガリウム再融着層Ａが形成される）と推察される。 In the conventional conventional laser lift-off, gallium nitride near the interface with the substrate 11 irradiated with a laser beam having a high energy density is decomposed into gallium and nitrogen, and gasified nitrogen is dissipated, so that the interface with the substrate 11 is reduced. Peels off.
On the other hand, in the case of the laser beam having a small energy density applied in step S2, the laser beam is not of such an extent that gallium nitride is decomposed into gallium and nitrogen and gasified nitrogen is dissipated. It is presumed that the element 10 is re-fused (the nitrogen-gallium re-fused layer A is formed at the interface between the sapphire substrate 11 and the semiconductor element 10). Alternatively, it is presumed that a part of the gallium nitride that has not been ablated remains at the interface between the sapphire substrate 11 and the semiconductor element 10 (a nitrogen gallium re-fusion layer A is formed).
　その結果、基板１１と半導体素子１０との界面（窒素ガリウム再融着層Ａ）におけるシェア強度（接着強度）は、後の工程における半導体素子１０を回路基板に接着する際の接着強度よりも小さい状態となる。例えば、窒素ガリウム再融着層Ａは、シェア強度が２３０ｋｇ／ｃｍ２以下となる。 As a result, the shear strength (adhesion strength) at the interface between the substrate 11 and the semiconductor element 10 (nitrogen gallium re-fusion layer A) is smaller than the adhesion strength when the semiconductor element 10 is bonded to the circuit board in a later step. State. For example, the nitrogen gallium re-fusion layer A has a shear strength of 230 kg / cm 2 or less.
　なお、ステップＳ２にて照射されるレーザ光Ｌは、各半導体素子１０に対して複数回の照射であることが好ましく、その照射回数は各半導体素子１０に対して、１０回以上であることが好ましい。より好ましくは、１０回～２０回である。
　照射されるレーザ光のエネルギー密度は必ずしも一定ではないので、複数回に分けることでバラツキを相殺し、半導体素子１０が基板１１から剥離するエネルギー密度を超えないようにするためである。 In addition, it is preferable that the laser beam L irradiated in step S2 is applied to each semiconductor element 10 a plurality of times, and the number of times of irradiation is 10 or more times for each semiconductor element 10. preferable. More preferably, it is 10 to 20 times.
The energy density of the irradiated laser beam is not necessarily constant, so that the energy density is divided into a plurality of times to offset the variation and to prevent the semiconductor element 10 from exceeding the energy density at which the semiconductor element 10 is separated from the substrate 11.
　このステップＳ２における工程が、本発明の実施形態に係る半導体素子形成サファイア基板の製造方法に相当しており、このステップＳ２を経ることで、本発明の実施形態に係る半導体素子形成サファイア基板が製造される。 The process in step S2 corresponds to the method for manufacturing a sapphire substrate on which a semiconductor element is formed according to the embodiment of the present invention. Through this step S2, the sapphire substrate on which a semiconductor element is formed according to the embodiment of the present invention is manufactured Is done.
　（半導体素子転写方法）
　本発明の半導体素子転写方法にかかる実施形態について、図５、図７、図８、図９に基づいて説明する。
　まず、上記した窒素ガリウム再融着層Ａが形成された半導体素子形成サファイア基板を用意する。
　一方、前記窒素ガリウム再融着層Ａのシェア強度（接着強度）よりも大きなシェア強度（接着強度）を有する接着層を、図示しないが、前記サファイア基板上の半導体素子、あるいは回路基板に形成する。
　そして、前記窒素ガリウム再融着層Ａが形成された半導体素子形成サファイア基板１２を回路基板１４のもとに搬送し（図５参照）、図７に示すように基板１１上に配列された半導体素子１０を回路基板１４に対して位置合わせを行う（図５のステップＳ３）。 (Semiconductor element transfer method)
An embodiment according to a semiconductor element transfer method of the present invention will be described with reference to FIGS. 5, 7, 8, and 9. FIG.
First, a sapphire substrate on which a semiconductor element is formed on which the above-mentioned nitrogen gallium re-fusion layer A is formed is prepared.
On the other hand, an adhesive layer having a greater shear strength (adhesive strength) than the shear strength (adhesive strength) of the nitrogen-gallium re-fusion layer A is formed on a semiconductor element on the sapphire substrate or a circuit board, though not shown. .
Then, the semiconductor element forming sapphire substrate 12 on which the nitrogen-gallium re-fusion layer A is formed is transported under the circuit board 14 (see FIG. 5), and the semiconductors arranged on the substrate 11 as shown in FIG. The element 10 is aligned with the circuit board 14 (Step S3 in FIG. 5).
　図７に示すように、回路基板１４には電極１５が設けられている。この電極１５は、半導体素子１０に設けられた電極１３と電気的に接続するためのものである。
　したがって、回路基板１４の電極１５と半導体素子１０の電極１３とが正しく位置合わせされなければ、半導体素子１０を正しく導通することはできない。
　図７に示す半導体素子形成サファイア基板１２は、半導体素子１０が、窒素ガリウム再融着層Ａを介してサファイア基板１１に保持された状態にある。そのため、半導体素子１０の製造時における高い位置精度が維持された状態で、回路基板１４に対して半導体素子１０を位置合わせすることができる。
　更に言えば、従来の半導体素子１０を粘着フィルムに転写した後に回路基板１４に位置合わせする方法と比較して、ステップＳ３における位置合わせの精度は、非常に高いものとなる。 As shown in FIG. 7, an electrode 15 is provided on the circuit board 14. The electrode 15 is for electrically connecting to the electrode 13 provided on the semiconductor element 10.
Therefore, unless the electrodes 15 of the circuit board 14 and the electrodes 13 of the semiconductor element 10 are properly aligned, the semiconductor element 10 cannot be properly conducted.
The semiconductor element formation sapphire substrate 12 shown in FIG. 7 is in a state where the semiconductor element 10 is held on the sapphire substrate 11 via the nitrogen gallium re-fusion layer A. Therefore, the semiconductor element 10 can be positioned with respect to the circuit board 14 while maintaining high positional accuracy during the manufacture of the semiconductor element 10.
Furthermore, as compared with the conventional method of transferring the semiconductor element 10 to the adhesive film and then positioning the semiconductor element 10 on the circuit board 14, the positioning accuracy in Step S3 is extremely high.
　次に、図８に示すように、半導体素子形成サファイア基板１２を回路基板１４に対して押圧しながら、半導体素子１０を回路基板１４に接着する（図５のステップＳ４）。
　このステップＳ４における接着工程では、回路基板１４の電極１５と半導体素子１０の電極１３との間の電気的接続を確保しながら、半導体素子１０が回路基板１４に固定されるように、公知の方法にて半導体素子１０を前記回路基板１４に、前記接着層を介して接着する。 Next, as shown in FIG. 8, the semiconductor element 10 is bonded to the circuit board 14 while pressing the semiconductor element forming sapphire substrate 12 against the circuit board 14 (Step S4 in FIG. 5).
In the bonding step in step S4, a known method is used so that the semiconductor element 10 is fixed to the circuit board 14 while securing electrical connection between the electrode 15 of the circuit board 14 and the electrode 13 of the semiconductor element 10. Then, the semiconductor element 10 is bonded to the circuit board 14 via the bonding layer.
　この接着層を構成する接着剤としては、一般的な感光性接着剤を用いることができる。尚、前記したように、この接着剤の接着力（シェア強度）は、接着剤の種類にもよるが、おおよそ１００ｋｇ／ｃｍ２～４００ｋｇ／ｃｍ２である。 As the adhesive constituting the adhesive layer, a general photosensitive adhesive can be used. Incidentally, as described above, the adhesive force of the adhesive (shear strength), depending on the type of adhesive is approximately 100kg / cm 2 ~ 400kg / cm 2.
　最後に、図９に示すように、サファイア基板１１を半導体素子１０から剥離する剥離工程（図５のステップＳ５）を行う。
　この剥離工程は、回路基板１４に対する半導体素子１０の接着強度（接着層の接着強度）を用いて、サファイア基板１１から半導体素子１０を剥離する。既に述べたように、窒素ガリウム再融着層Ａによって、サファイア基板１１と半導体素子１０との接着強度（シェア強度）は、半導体素子１０を回路基板１４に接着する接着層の接着強度（シェア強度）よりも小さい。
　したがって、回路基板１４に対してサファイア基板１１を引き剥がすことにより、半導体素子１０はサファイア基板１１から剥離される。即ち、半導体素子１０がサファイア基板１１から回路基板１４へ乗せ換えられた（転写された）ことになる。 Finally, as shown in FIG. 9, a peeling step of peeling the sapphire substrate 11 from the semiconductor element 10 (Step S5 in FIG. 5) is performed.
In this peeling step, the semiconductor element 10 is peeled from the sapphire substrate 11 using the adhesive strength of the semiconductor element 10 to the circuit board 14 (the adhesive strength of the adhesive layer). As described above, the bonding strength (share strength) between the sapphire substrate 11 and the semiconductor element 10 by the nitrogen-gallium re-fusion layer A is determined by the bonding strength (share strength) of the bonding layer that bonds the semiconductor element 10 to the circuit board 14. ) Less than.
Therefore, the semiconductor element 10 is peeled from the sapphire substrate 11 by peeling the sapphire substrate 11 from the circuit board 14. That is, the semiconductor element 10 is transferred (transferred) from the sapphire substrate 11 to the circuit substrate 14.
　以上のように、本発明の実施形態に係る半導体素子転写方法（図５のステップＳ３からステップＳ５）には、従来のような半導体素子を剥離するレーザ光を照射する工程を含まない。
　したがって、半導体素子の利用者は、レーザ光の照射装置を用いることなく、高精度にサファイア基板１１から回路基板１４へ半導体素子１０を乗せ換える（転写する）ことができる。 As described above, the method of transferring a semiconductor element (steps S3 to S5 in FIG. 5) according to the embodiment of the present invention does not include a conventional step of irradiating a laser beam for peeling a semiconductor element.
Therefore, the user of the semiconductor device can transfer (transfer) the semiconductor device 10 from the sapphire substrate 11 to the circuit substrate 14 with high accuracy without using a laser beam irradiation device.
　（前処理工程）
　ここで、上記説明した前処理工程（ステップＳ２）の詳細および変形例について説明する。
　前述したように、前処理工程（ステップＳ２）は、半導体素子１０の形成後に、半導体素子１０をサファイア基板１１から剥離するのを容易にするためのものであり、半導体素子１０とサファイア基板１１の界面に対して、半導体素子１０がサファイア基板１１から剥離するレーザ光のエネルギー密度よりも小さいエネルギー密度のレーザ光をサファイア基板１１の裏面側から複数回照射する。 (Pretreatment step)
Here, details and modifications of the above-described pre-processing step (step S2) will be described.
As described above, the pre-processing step (Step S2) is for facilitating peeling of the semiconductor element 10 from the sapphire substrate 11 after the formation of the semiconductor element 10, The interface is irradiated with laser light having an energy density smaller than the energy density of the laser light peeled from the sapphire substrate 11 by the semiconductor element 10 a plurality of times from the back surface side of the sapphire substrate 11.
　ここで、半導体素子がサファイア基板から剥離するレーザ光のエネルギー密度よりも小さいエネルギー密度とは、一般的な従前のレーザリフトオフにて用いられるエネルギー密度よりも低いエネルギー密度という意味であり、図１０は、レーザ光のエネルギー密度および照射回数（ショット数）と半導体素子がサファイア基板から剥離する条件との関係を示す図である。 Here, the energy density smaller than the energy density of the laser beam that separates the semiconductor element from the sapphire substrate means that the energy density is lower than the energy density used in general conventional laser lift-off, and FIG. FIG. 4 is a diagram showing the relationship between the energy density of laser light, the number of irradiations (the number of shots), and the conditions under which the semiconductor element peels off from the sapphire substrate.
　図１０に示すように、半導体素子１０とサファイア基板１１の界面に対して、サファイア基板１１の裏面側からレーザ光を照射した後の半導体素子１０とサファイア基板１１の界面の状態は、大きく分けて３つの状態に分けることができる。すなわち、レーザ光を照射した後でも半導体素子１０とサファイア基板１１の間の密着状態が変わらない状態（領域（ａ））と、レーザ光を照射した後に半導体素子１０がサファイア基板１１から剥離してしまう状態（領域（ｂ））と、レーザ光を照射した後に半導体素子１０とサファイア基板１１の間に窒素ガリウム再融着層が形成される状態（領域（ｃ））である。
　なお、ここで窒素ガリウム再融着層とは、具体的組成までは明らかではないものの、エネルギー密度の小さいレーザ光の場合にも、一部の窒化ガリウムはガリウムと窒素に分解され、その気体化された一部の窒素が消散されると推察される。したがって、窒素ガリウム再融着層には、ガリウムが単体で固体化されたものやアブレーションしなかった窒化ガリウムの一部が残存すると推察されている。 As shown in FIG. 10, the state of the interface between the semiconductor element 10 and the sapphire substrate 11 after irradiating the interface between the semiconductor element 10 and the sapphire substrate 11 with laser light from the back side of the sapphire substrate 11 can be roughly divided. It can be divided into three states. That is, the state in which the close contact state between the semiconductor element 10 and the sapphire substrate 11 does not change even after the laser light irradiation (area (a)), and the state in which the semiconductor element 10 peels off from the sapphire substrate 11 after the laser light irradiation. There is a state (region (b)) and a state (region (c)) in which a nitrogen gallium re-fusion layer is formed between the semiconductor element 10 and the sapphire substrate 11 after the laser beam irradiation.
Although the specific composition of the nitrogen-gallium re-fusion layer is not clear here, even in the case of laser light with a low energy density, some gallium nitride is decomposed into gallium and nitrogen, It is presumed that some of the nitrogen released is dissipated. Therefore, it is presumed that gallium solidified alone or part of gallium nitride not ablated remains in the nitrogen gallium re-fusion layer.
　図１０に示されるグラフから解るように、前処理工程（ステップＳ２）にて窒素ガリウム再融着層を形成し得る条件（プロセスマージン）は狭い。照射するレーザ光のエネルギー密度がＥ１よりも低い場合は、半導体素子１０とサファイア基板１１の間の密着状態が変わらず、所望の窒素ガリウム再融着層を形成することができない。一方、照射するレーザ光のエネルギー密度がＥ３よりも高い場合は、半導体素子１０がサファイア基板１１から剥離してしまう。
　また、照射するレーザ光のエネルギー密度がＥ３より低くても、レーザ光の照射回数（ショット数）がｎ１以上でないと、窒素ガリウム再融着層を形成することができない。 As can be seen from the graph shown in FIG. 10, the conditions (process margin) under which the nitrogen-gallium re-fused layer can be formed in the pretreatment step (step S2) are narrow. When the energy density of the irradiated laser beam is lower than E1, the adhesion state between the semiconductor element 10 and the sapphire substrate 11 does not change, and a desired nitrogen gallium re-fusion layer cannot be formed. On the other hand, when the energy density of the irradiated laser beam is higher than E3, the semiconductor element 10 is separated from the sapphire substrate 11.
Further, even if the energy density of the laser light to be irradiated is lower than E3, the nitrogen-gallium re-fusion layer cannot be formed unless the number of laser light irradiations (the number of shots) is at least n1.
　そこで、前処理工程（ステップＳ２）におけるプロセスマージンを広げるために、以下に示す工夫を施すことが考えられる。一つは、半導体素子１０とサファイア基板１１の間を加圧させながら、レーザ光をサファイア基板１１の裏面側から照射する方法であり、もう一つは、半導体素子１０とサファイア基板１１の界面の領域を複数に分けて、レーザ光をサファイア基板１１の裏面側から照射する方法である。 Therefore, in order to increase the process margin in the pre-processing step (step S2), the following measures may be taken. One is a method of irradiating a laser beam from the back surface side of the sapphire substrate 11 while applying pressure between the semiconductor device 10 and the sapphire substrate 11, and the other is a method of irradiating the interface between the semiconductor device 10 and the sapphire substrate 11. This is a method in which a region is divided into a plurality of regions and a laser beam is irradiated from the back side of the sapphire substrate 11.
　半導体素子１０とサファイア基板１１の間を加圧させながら、レーザ光をサファイア基板１１の裏面側から照射する方法としては、例えば図１１に示すように石英ガラス等の透明板を用いる方法や図１２に示すように粘着フィルムを用いる方法が採用し得る。 As a method of irradiating a laser beam from the back side of the sapphire substrate 11 while applying pressure between the semiconductor element 10 and the sapphire substrate 11, for example, a method using a transparent plate such as quartz glass as shown in FIG. As shown in the above, a method using an adhesive film can be adopted.
　図１１に示すように、石英ガラス等の透明板を用いる方法では、半導体素子１０を加工ステージ１４０側にして加工ステージ１４０の上にサファイア基板１１を載置し、石英ガラス１６を用いてサファイア基板１１を加工ステージ１４０に加圧しながらレーザ光を照射する。
　また、図１２に示すように、粘着フィルムを用いる方法では、半導体素子１０を形成したサファイア基板１１の面に弾力性を有する粘着フィルム１７を貼付した状態でレーザ光をサファイア基板１１の裏面側から照射する。すると、図１２中の部分拡大図に示すように、粘着フィルム１７の弾力性によって半導体素子１０がサファイア基板１１に加圧された状態でレーザ光をサファイア基板１１の裏面側から照射することになる。 As shown in FIG. 11, in the method using a transparent plate such as quartz glass, the sapphire substrate 11 is placed on the processing stage 140 with the semiconductor element 10 facing the processing stage 140, and the sapphire substrate is The laser beam is irradiated while pressing 11 on the processing stage 140.
As shown in FIG. 12, in the method using an adhesive film, a laser beam is applied from the back side of the sapphire substrate 11 with the elastic adhesive film 17 attached to the surface of the sapphire substrate 11 on which the semiconductor element 10 is formed. Irradiate. Then, as shown in the partial enlarged view of FIG. 12, the semiconductor element 10 is irradiated with laser light from the back side of the sapphire substrate 11 in a state where the semiconductor element 10 is pressed against the sapphire substrate 11 by the elasticity of the adhesive film 17. .
　図１３は、上記説明した方法にしたがって、半導体素子１０とサファイア基板１１の間を加圧させながらレーザ光をサファイア基板１１の裏面側から照射する場合のレーザ光のエネルギー密度および照射回数（ショット数）と半導体素子がサファイア基板から剥離する条件との関係を示す図である。
　図１３と図１０を比較すると解るように、半導体素子１０とサファイア基板１１の間を加圧させながらレーザ光をサファイア基板１１の裏面側から照射する場合、グラフ全体が縦方向に広がっている。このことは、照射するレーザ光のエネルギー密度が、加圧しない場合よりも加圧する方が高くなるということである。具体的には、エネルギー密度がＥ１であったものがＥ１′に上昇し、エネルギー密度がＥ２であったものがＥ２′に上昇し、エネルギー密度がＥ３であったものがＥ３′に上昇している。 FIG. 13 shows the energy density and the number of irradiations (the number of shots) of the laser beam when the laser beam is irradiated from the back side of the sapphire substrate 11 while applying pressure between the semiconductor element 10 and the sapphire substrate 11 according to the method described above. FIG. 4 is a diagram showing the relationship between the condition (1) and the condition under which the semiconductor element is separated from the sapphire substrate.
As can be understood from a comparison between FIG. 13 and FIG. 10, when the laser beam is irradiated from the back surface side of the sapphire substrate 11 while applying pressure between the semiconductor element 10 and the sapphire substrate 11, the entire graph spreads in the vertical direction. This means that the energy density of the irradiated laser light is higher when the pressure is applied than when the pressure is not applied. Specifically, the energy density of E1 rises to E1 ', the energy density of E2 rises to E2', and the energy density of E3 rises to E3 '. I have.
　一方、このことは前処理工程（ステップＳ２）にて窒素ガリウム再融着層を形成し得る条件（プロセスマージン）が広がったことになっている。例えば、加圧しない状態で前処理工程（ステップＳ２）を行ったときのプロセスマージンがエネルギー密度５０～６０ｍＪ／ｃｍ２かつショット数が２０回以上である場合には、半導体素子１０とサファイア基板１１の間を加圧させながらレーザ光をサファイア基板１１の裏面側から照射すると、プロセスマージンがエネルギー密度６０～１００ｍＪ／ｃｍ２かつショット数が２０回以上に広がる。エネルギー密度の側面に限って言えば、プロセスマージンが１０ｍＪ／ｃｍ２であったものが４０ｍＪ／ｃｍ２に広がっているので、その差は顕著である。
　プロセスマージンが広がるということは、前処理工程（ステップＳ２）にて窒素ガリウム再融着層を形成すること容易にすると共に、不良品の発生率を低減することにも繋がる。 On the other hand, this means that conditions (process margin) for forming the nitrogen-gallium re-fused layer in the pre-treatment step (step S2) have been widened. For example, if the process margin when performing the pre-processing step (step S2) without applying pressure has an energy density of 50 to 60 mJ / cm 2 and the number of shots is 20 or more, the semiconductor element 10 and the sapphire substrate 11 When the laser light is irradiated from the back side of the sapphire substrate 11 while the pressure is increased, the process margin is increased to an energy density of 60 to 100 mJ / cm 2 and the number of shots is increased to 20 or more. As far as the side surface of the energy density, since those process margin was 10 mJ / cm 2 is spread 40 mJ / cm 2, the difference is significant.
The increase in the process margin facilitates the formation of the nitrogen-gallium re-fused layer in the pretreatment step (step S2), and also reduces the occurrence of defective products.
　上記説明した方法は、別途の冶具ないし部品を用いて半導体素子１０とサファイア基板１１の間を加圧させるものであるが、図１４および図１５に示す、半導体素子とサファイア基板の界面の領域を複数に分けてレーザ光を照射する方法においても、実質的に加圧するのと同じ効果を得ることができる。
そのため、図１４および図１５に基づいて、半導体素子とサファイア基板の界面の領域を複数に分けてレーザ光を照射する方法についても説明する。 In the method described above, the pressure between the semiconductor element 10 and the sapphire substrate 11 is pressurized by using a separate jig or component, but the area of the interface between the semiconductor element and the sapphire substrate shown in FIGS. Even in the method of irradiating the laser light in a plurality of parts, substantially the same effect as pressurizing can be obtained.
Therefore, a method for irradiating a laser beam by dividing an interface region between a semiconductor element and a sapphire substrate into a plurality of regions will be described with reference to FIGS.
　図１４は、半導体素子１０とサファイア基板１１の間の界面を、サファイア基板１１を介して観察した状態を模式的に示している。図１４に示すように、この照射方法では、半導体素子１０とサファイア基板１１の界面の領域を複数に分けて、レーザ光をサファイア基板１１の裏面側から照射する。
　この図１４に示される例では、レーザ光の照射領域Ｌが半導体素子１０とサファイア基板１１の間の界面の領域よりも狭く設定されており、２回に分けて半導体素子１０とサファイア基板１１の間の界面の全領域を加工している。
　なお、この前処理工程（ステップＳ２）では、レーザ光を複数回照射することが前提とされているが、領域を複数に分ける場合は、各領域にレーザ光を複数回照射するようにする。 FIG. 14 schematically shows a state in which the interface between the semiconductor element 10 and the sapphire substrate 11 is observed through the sapphire substrate 11. As shown in FIG. 14, in this irradiation method, the region of the interface between the semiconductor element 10 and the sapphire substrate 11 is divided into a plurality of regions, and laser light is irradiated from the back surface side of the sapphire substrate 11.
In the example shown in FIG. 14, the irradiation area L of the laser beam is set to be narrower than the area of the interface between the semiconductor element 10 and the sapphire substrate 11, and the semiconductor element 10 and the sapphire substrate 11 are divided into two times. The entire area of the interface between them is processed.
In this preprocessing step (step S2), it is assumed that the laser light is irradiated a plurality of times. However, when the region is divided into a plurality of regions, each region is irradiated with the laser light a plurality of times.
　図１５は、半導体素子１０とサファイア基板１１の間の界面を、サファイア基板１１を介して観察した状態を模式的に示している。図１５に示すように、この照射方法では、半導体素子１０とサファイア基板１１の界面の領域をストライプ状に複数に分けて、ストライプ状の照射領域Ｌのレーザ光をサファイア基板１１の裏面側から照射しながら図中矢印方向に移動させる。このような照射方法を用いても、半導体素子１０とサファイア基板１１の間の界面の領域を複数に分けて各領域にレーザ光を複数回照射することになる。 FIG. 15 schematically shows a state where the interface between the semiconductor element 10 and the sapphire substrate 11 is observed through the sapphire substrate 11. As shown in FIG. 15, in this irradiation method, the region of the interface between the semiconductor element 10 and the sapphire substrate 11 is divided into a plurality of stripes, and the laser light in the stripe-shaped irradiation region L is irradiated from the back side of the sapphire substrate 11. While moving in the direction of the arrow in the figure. Even if such an irradiation method is used, the region of the interface between the semiconductor element 10 and the sapphire substrate 11 is divided into a plurality of regions, and each region is irradiated with laser light a plurality of times.
　上記図１４および図１５に示したようなレーザ光の照射領域Ｌを形成するためには、半導体素子１０とサファイア基板１１の界面の領域よりも小さい領域を照射するように設計された投影マスクを介してレーザ光照射するのが好ましい。
　半導体素子１０とサファイア基板１１の界面の領域よりも小さい照射領域Ｌのレーザ光を照射した場合、レーザ光が照射されていない領域が常に残っており、当該領域では半導体素子１０とサファイア基板１１の間の密着状態が変わらず維持される。
　したがって、この密着状態が維持された領域における密着力が、レーザ光が照射されて加工が進行している領域に対して加圧作用する。
　すなわち、半導体素子１０とサファイア基板１１の界面の領域を複数に分けて、レーザ光を照射する方法は、半導体素子１０とサファイア基板１１の間を加圧させながらレーザ光照射するのと同様の効果を奏するものとなる。 In order to form the laser light irradiation region L as shown in FIGS. 14 and 15, a projection mask designed to irradiate a region smaller than the region at the interface between the semiconductor element 10 and the sapphire substrate 11 is required. It is preferable to irradiate the laser beam through the interface.
When the laser light in the irradiation region L smaller than the region of the interface between the semiconductor element 10 and the sapphire substrate 11 is irradiated, a region not irradiated with the laser light always remains. The close contact state between them is maintained without change.
Therefore, the adhesion force in the area where the close contact state is maintained exerts a pressurizing action on the area where the laser beam is irradiated and the processing is in progress.
That is, the method of irradiating the laser light by dividing the region of the interface between the semiconductor element 10 and the sapphire substrate 11 into a plurality of parts has the same effect as that of irradiating the laser light while applying pressure between the semiconductor element 10 and the sapphire substrate 11. Will be played.
　尚、上記実施形態では、窒化ガリウム系半導体素子として、窒化ガリウム系の発光ダイオードの場合を例にとって説明したが、本発明はこれに限定されるものではない。 In the above embodiment, the gallium nitride-based semiconductor device is described by taking a gallium nitride-based light emitting diode as an example, but the present invention is not limited to this.
　１０　　窒化ガリウム系半導体素子
　１１　　（サファイア）基板
　１２　　半導体素子形成サファイア基板
　１３　　電極
　１４　　回路基板
　１５　　電極
　１００　レーザ加工装置 REFERENCE SIGNS LIST 10 gallium nitride based semiconductor element 11 (sapphire) substrate 12 sapphire substrate for forming semiconductor element 13 electrode 14 circuit board 15 electrode 100 laser processing apparatus

Claims (11)

  1. 　窒化ガリウム系半導体素子がサファイア基板上に配列形成された半導体素子形成サファイア基板であって、
    　前記サファイア基板と前記半導体素子との界面に窒素ガリウム再融着層を有し、
    　前記窒素ガリウム再融着層の接着強度が、前記半導体素子を回路基板に接着する接着層の接着強度よりも小さいことを特徴とする半導体素子形成サファイア基板。     A gallium nitride based semiconductor device is a semiconductor device formed sapphire substrate arranged and formed on a sapphire substrate,
    At the interface between the sapphire substrate and the semiconductor element has a nitrogen gallium re-fusion layer,
    A semiconductor element-formed sapphire substrate, wherein the adhesive strength of the nitrogen-gallium re-fusion layer is smaller than the adhesive strength of an adhesive layer for bonding the semiconductor element to a circuit board.
  2. 　前記サファイア基板と前記半導体素子との界面の窒素ガリウム再融着層の接着強度が、シェア強度で２３０ｋｇ／ｃｍ２以下であることを特徴とする請求項１記載の半導体素子形成サファイア基板。 2. The sapphire substrate according to claim 1, wherein an adhesive strength of a nitrogen gallium re-fusion layer at an interface between the sapphire substrate and the semiconductor element is 230 kg / cm 2 or less in shear strength. 3.
  3. 　窒化ガリウム系半導体素子をサファイア基板上に形成し、その後、前記半導体素子をサファイア基板から剥離するための剥離前処理がなされる半導体素子形成サファイア基板の製造方法において、
    　前記剥離前処理には、半導体素子とサファイア基板の界面に対して、前記サファイア基板の裏面側からレーザ光を照射し、窒素ガリウム再融着層を形成する工程を含み、
    　前記工程におけるレーザ光は、半導体素子が前記サファイア基板から剥離するレーザ光のエネルギー密度よりも小さいエネルギー密度で照射されることにより、
    　レーザ光照射後、前記窒素ガリウム再融着層により、サファイア基板と半導体素子が、半導体素子を回路基板に接着する接着層の接着強度よりも小さい接着強度で、保持されていることを特徴とする半導体素子形成サファイア基板の製造方法。     Forming a gallium nitride-based semiconductor element on a sapphire substrate, and thereafter, a method for manufacturing a semiconductor element-formed sapphire substrate, in which pre-peeling treatment for separating the semiconductor element from the sapphire substrate is performed,
    The pre-peeling treatment includes irradiating a laser beam to the interface between the semiconductor element and the sapphire substrate from the back side of the sapphire substrate to form a nitrogen-gallium re-fusion layer,
    The laser light in the step is irradiated with an energy density smaller than the energy density of the laser light in which the semiconductor element is separated from the sapphire substrate,
    After the laser beam irradiation, the sapphire substrate and the semiconductor element are held by the nitrogen-gallium re-fusion layer with an adhesive strength smaller than the adhesive strength of the adhesive layer for bonding the semiconductor element to the circuit board. A method for manufacturing a sapphire substrate on which a semiconductor element is formed.
  4. 　前記サファイア基板と半導体素子が、シェア強度で２３０ｋｇ／ｃｍ２以下の窒素ガリウム再融着層で保持されることを特徴とする請求項３記載の半導体素子形成サファイア基板の製造方法。 4. The method according to claim 3, wherein the sapphire substrate and the semiconductor element are held by a nitrogen-gallium re-fusion layer having a shear strength of 230 kg / cm 2 or less.
  5. 　前記工程における前記レーザ光は、前記窒化ガリウム系半導体素子の各々に対して複数回の照射されることを特徴とする請求項３に記載された半導体素子形成サファイア基板の製造方法。 4. The method according to claim 3, wherein the laser beam in the step is applied to each of the gallium nitride-based semiconductor elements a plurality of times. 5.
  6. 　前記工程における前記レーザ光は、前記窒化ガリウム系半導体素子の各々に対して複数回の照射されることを特徴とする請求項４に記載された半導体素子形成サファイア基板の製造方法。 The method according to claim 4, wherein the laser beam in the step is applied to each of the gallium nitride-based semiconductor elements a plurality of times.
  7. 　窒化ガリウム系半導体素子がサファイア基板上に形成された半導体素子形成サファイア基板の製造方法において、
    　前記窒化ガリウム系半導体素子の形成後になされる、前記半導体素子をサファイア基板から剥離するための剥離前処理工程を含み、
    　前記剥離前処理工程では、前記窒化ガリウム系半導体素子と前記サファイア基板の界面に対して、前記窒化ガリウム系半導体素子が前記サファイア基板から剥離するレーザ光のエネルギー密度よりも小さいエネルギー密度のレーザ光を前記サファイア基板の裏面側から複数回照射する、
    　ことを特徴とする半導体素子形成サファイア基板の製造方法。     In a method of manufacturing a semiconductor element formed sapphire substrate in which a gallium nitride based semiconductor element is formed on a sapphire substrate,
    After the formation of the gallium nitride based semiconductor element, including a pre-peeling treatment step for separating the semiconductor element from the sapphire substrate,
    In the pre-peeling treatment step, a laser beam having an energy density smaller than the energy density of the laser beam from which the gallium nitride-based semiconductor device peels off from the sapphire substrate is applied to an interface between the gallium nitride-based semiconductor device and the sapphire substrate. Irradiating a plurality of times from the back side of the sapphire substrate,
    A method for manufacturing a sapphire substrate on which a semiconductor element is formed, characterized by comprising:
  8. 　前記剥離前処理工程では、前記窒化ガリウム系半導体素子と前記サファイア基板の間を加圧させながら、前記レーザ光を前記サファイア基板の裏面側から照射する、
    　ことを特徴とする請求項７に記載の半導体素子形成サファイア基板の製造方法。     In the pre-peeling step, the laser beam is irradiated from the back side of the sapphire substrate while applying pressure between the gallium nitride based semiconductor device and the sapphire substrate.
    The method for manufacturing a sapphire substrate on which a semiconductor element is formed according to claim 7.
  9. 　前記剥離前処理工程では、前記窒化ガリウム系半導体素子と前記サファイア基板の界面の領域を複数に分けて、前記レーザ光を前記サファイア基板の裏面側から照射する、
    　ことを特徴とする請求項７に記載の半導体素子形成サファイア基板の製造方法。     In the pre-peeling treatment step, the interface region between the gallium nitride-based semiconductor element and the sapphire substrate is divided into a plurality of regions, and the laser light is irradiated from the back side of the sapphire substrate.
    The method for manufacturing a sapphire substrate on which a semiconductor element is formed according to claim 7.
  10. 　前記剥離前処理工程では、前記窒化ガリウム系半導体素子と前記サファイア基板の界面の領域よりも小さい領域を照射するように設計された投影マスクを介して、前記レーザ光を前記サファイア基板の裏面側から照射する、
    　ことを特徴とする請求項９に記載の半導体素子形成サファイア基板の製造方法。     In the pre-peeling treatment step, the laser light is applied from a back side of the sapphire substrate through a projection mask designed to irradiate a region smaller than an interface region between the gallium nitride based semiconductor element and the sapphire substrate. Irradiate,
    The method for manufacturing a sapphire substrate on which a semiconductor element is formed according to claim 9.
  11. 　請求項１または請求項２に記載された半導体素子形成サファイア基板、または請求項３乃至請求項１０のいずれかの半導体素子形成サファイア基板の製造方法により製造された半導体素子形成サファイア基板を用意する工程と、
    　前記サファイア基板と前記半導体素子の界面の窒素ガリウム再融着層の接着強度よりも大きな接着強度を有する接着層を、前記サファイア基板上の半導体素子あるいは回路基板に形成する工程と、
    　前記サファイア基板上に配列された半導体素子を、回路基板に対して位置合わせする位置合わせ工程と、
    　前記サファイア基板を回路基板に対して押圧しながら、半導体素子を前記回路基板に、前記接着層を介して接着する接着工程と、
    　前記接着層の接着力によって、前記サファイア基板から前記半導体素子を剥離し、前記回路基板に前記半導体素子を配置する剥離・配置工程と、
    　を含むことを特徴とするサファイア基板からの半導体素子転写方法。      A step of preparing a sapphire substrate for forming a semiconductor element according to claim 1 or claim 2, or a sapphire substrate for forming a semiconductor element manufactured by the method for manufacturing a sapphire substrate for forming a semiconductor element according to any one of claims 3 to 10. When,
    Forming an adhesive layer having an adhesive strength greater than the adhesive strength of the nitrogen gallium re-fusion layer at the interface between the sapphire substrate and the semiconductor element on the semiconductor element or the circuit board on the sapphire substrate;
    A semiconductor element arranged on the sapphire substrate, an alignment step of aligning with a circuit board,
    While pressing the sapphire substrate against the circuit board, a bonding step of bonding a semiconductor element to the circuit board via the bonding layer,
    A peeling / arranging step of peeling the semiconductor element from the sapphire substrate by the adhesive force of the adhesive layer and arranging the semiconductor element on the circuit board,
    A method for transferring a semiconductor device from a sapphire substrate, comprising:
PCT/JP2019/016277 2018-06-19 2019-04-16 Semiconductor element forming sapphire substrate, method of manufacturing semiconductor element forming sapphire substrate, and method of transferring semiconductor element WO2019244460A1 (en)

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JP2014132606A (en) * 2013-01-04 2014-07-17 Stanley Electric Co Ltd Method of manufacturing nitride semiconductor element
JP2014239171A (en) * 2013-06-10 2014-12-18 ソニー株式会社 Light-emitting element wafer, light-emitting element, electronic apparatus, and method of manufacturing light-emitting element wafer

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JP2007036131A (en) * 2005-07-29 2007-02-08 Canon Inc Film transfer method
JP2014075565A (en) * 2012-10-04 2014-04-24 Mtec:Kk Method of manufacturing compound semiconductor device
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