JP2012182278A - Laser lift-off device and laser lift-off method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize laser lift-off processing by radiating laser lights while holding a deformed workpiece without breaking it.SOLUTION: A workpiece 1, on which a sapphire substrate 1a, a material layer 1b, and a support substrate 1c are laminated, for example, which is deformed to project downward, is supported and located on a support rod 12 of a support mechanism 10 provided on a stage 20 at three points. The stage 20 is located on a conveying mechanism 2 such as a conveyor, and conveyed at a predetermined speed by the conveying mechanism 2. The workpiece 1 is irradiated with pulse laser lights L emitted from a pulse laser source (not shown) through the substrate 1a, while being conveyed together with the stage 20. The deformed workpiece 1 is not corrected into a plane shape, is supported under a deformed condition, and is subjected to laser lift-off processing. Therefore, even when the workpiece is significantly deformed, the workpiece can be processed without breaking it.

Description

  The present invention relates to a laser lift-off apparatus and method for peeling a material layer from a substrate by irradiating a workpiece having a material layer on the substrate with a laser beam in a wavelength region that passes through the substrate. The present invention relates to a laser lift-off device and a laser lift-off method capable of holding a work as it is, irradiating a laser beam, decomposing the material layer and peeling it from the substrate (hereinafter referred to as laser lift-off).

  In a manufacturing process of a semiconductor light emitting device formed of a gallium nitride (GaN) compound semiconductor, a GaN compound material layer formed on one surface of a sapphire substrate is irradiated with laser light from the other surface corresponding to the back surface of the sapphire substrate. A technique of laser lift-off that peels off by irradiation is known.

When performing the semiconductor exposure process or the laser lift-off process, usually, a work (wafer) that is an object to be irradiated is sucked and held on a work stage, and exposure light or laser light is irradiated from a light source.
When exposing a planar workpiece such as a silicon wafer used in the semiconductor exposure process, the workpiece is usually placed on the workpiece stage and exhausted from a plurality of exhaust holes provided in the workpiece stage. A method is used in which the space between the stages is depressurized and held on the stages.
Even if the workpiece is deformed irregularly or irregularly, if the deformation is slight and the workpiece itself can be deformed, it can be corrected to a flat surface using the above method. Can be held.

Moreover, when it deform | transforms upwards and the deformation | transformation amount is large, as described in patent document 1, the method of decompressing and adsorb | sucking and hold | maintaining a lower space is known, for example.
In the method described in Patent Document 1, a circuit board (work) deformed upwardly as shown in FIG. 9 is held as follows.
That is, a through-hole 102 is provided in the suction stage 101, and a vacuum suction bellows 103 is provided in the through-hole so as to protrude onto the suction stage 101. Then, the circuit board (work) 104 is vacuum-sucked by the vacuum suction bellows 103, the circuit board (work) is corrected into a flat shape, and is sucked and fixed to the board suction surface 105.

As a method of holding a workpiece deformed downward and irregularly deformed, a method using a plurality of support bars (lift pins) whose tip portion is elastically deformed and adsorbed to the workpiece surface is known. (Patent Document 2)
In the device described in Patent Document 2, the workpiece 110 is held on a stage 112 using lift pins 111 that attract the workpiece 110 as shown in FIG.
As shown in FIG. 10A, the lift pins 111 are provided at, for example, three locations through the through-hole 113 provided on the stage 112 so as to be movable up and down, as shown in FIG. The ring 111a is composed of an elastic member having a tube-shaped hollow portion, the column 111b, and the like. The hollow portion communicates with a negative pressure generating source such as a pneumatic unit 111c through a pipe 111b.

In order to hold the deformed workpiece on the stage 112, the lift pin 111 is raised on the surface of the stage 112 and brought into contact with the lower surface of the workpiece 110. When the lift pin 111 comes into contact with the workpiece, the ring 111a made of an elastic member is deformed according to the shape of the workpiece, the tip of the ring 111a is in close contact with the workpiece 110, and the lift pin 111 is vacuum-sucked to the lower surface of the workpiece 110.
When the lift pin 111 is lowered in this state, the workpiece 110 is pressed against the stage 112 while the deformation is corrected. When substantially the entire surface of the work 110 comes into contact with the surface of the stage 112, the air of the work 110 and the surface of the stage 112 is sucked through a vacuum suction hole (not shown) provided in the stage 112, and the work 110 is sucked and fixed to the stage surface. .

JP 2007-294781 A JP 2010-226039 A

In manufacturing an LED, for example, a work in which a gallium nitride layer is formed on a circular sapphire substrate is used. As described above, when a workpiece formed with a layer having a different expansion coefficient from that of the substrate is warped or deformed due to a difference in thermal expansion coefficient between the upper and lower materials when heating and cooling are repeated in the previous process.
For example, in the case of a work in which a gallium nitride layer is formed on a sapphire substrate of about 500 μm, a gallium nitride crystal layer is grown on the sapphire substrate at about 800 ° C. At this time, although the workpiece is flat, the sapphire substrate having a large expansion coefficient contracts greatly as it cools, so that the workpiece warps to the sapphire substrate side (the sapphire substrate side becomes the concave side).
When performing the laser lift-off process, since the laser beam is irradiated from the sapphire substrate side as described above, the work is placed on the work stage with the sapphire substrate facing up. Therefore, the work is usually placed on the work stage in a convex state.

When such a workpiece is held on the workpiece stage and a laser lift-off process is to be performed, the conventional workpiece stage or the workpiece stage described in Patent Document 1 or Patent Document 2 cannot be used.
This is because the workpiece in the laser lift-off process is warped and deformed as described above, and the amount of warpage and deformation is large and the rigidity is higher than that of the silicon wafer. That is, as in the conventional holding method, when the workpiece is corrected to a flat surface and is intended to be sucked and fixed to the stage surface, the workpiece may be damaged.
In many cases, the workpiece in the laser lift-off process is placed on the workpiece stage in a downwardly convex state, and therefore cannot be sucked and held by the method described in Patent Document 1.
Further, when the laser lift-off process is attempted in a state where the workpiece is held by the lift pin described in Patent Document 2, a part of the lift pin is deformed by an elastic member. When the stage is moved, positional displacement or vibration due to deformation of the lift pin occurs due to acceleration / deceleration when the stage is moved, and cannot be stably held.
The present invention has been made based on the above circumstances, and it is an object of the present invention to provide a laser lift-off apparatus and method capable of performing laser lift-off processing by holding a deformed workpiece without damaging it and irradiating a laser beam.

In the conventional exposure process, even if the workpiece is warped or deformed, the workpiece is basically pressed against the workpiece stage surface to form a flat surface for exposure processing.
In contrast, many workpieces in the laser lift-off process are greatly deformed as described above. As is conventionally done, when a workpiece is pressed against a workpiece stage surface to correct it into a flat surface, the workpiece is likely to be broken or broken.
Therefore, in the present invention, even if the workpiece is warped or deformed, it is held on the stage as it is, and the laser lift-off process is performed. Therefore, in this invention, the support body which supports a workpiece | work at 3 points | pieces is provided on a stage, and it supports on a stage in the state which deform | transformed the workpiece | work. The deformed workpiece is irradiated with laser light to perform laser lift-off processing. As a laser source for emitting laser light, a light source capable of irradiating a workpiece with laser light having an energy level exceeding the decomposition threshold of the material layer is used.
Thereby, the laser lift-off process can be performed without damaging the workpiece. Moreover, since it supported by 3 points | pieces, regardless of the deformation | transformation state of a workpiece | work, a workpiece | work can be supported, without applying unnecessary force to a workpiece | work.
When performing the laser lift-off process, it is necessary to precisely position the irradiation position, and a method of intermittently moving the work and irradiating a plurality of exposure areas with laser light may be used. Because there are many, it is necessary to prevent the position of the workpiece from shifting or vibrating as it moves. Therefore, it is desirable to provide a mechanism for pressing the workpiece toward the support so that the workpiece does not move.

Based on the above, in the present invention, the above-described problem is solved as follows.
(1) A material layer is formed on a substrate, and the substrate is transmitted from the laser source while moving the laser beam from the laser source and the workpiece relative to the workpiece deformed upward or downward. A laser lift-off device for irradiating a laser beam in a wavelength range to peel off the material layer from the substrate, comprising a stage having a support mechanism for supporting the workpiece, the support mechanism protruding from the stage And a workpiece support that supports the workpiece in a deformed state. The laser source irradiates the deformed workpiece with laser light having an energy level exceeding a decomposition threshold of the material layer. .
(2) In the above (1), the work support includes three support bars projecting from the stage, and the support mechanism has pressing means for pressing the work toward the support bars.
(3) In the above (2), the support rod of the workpiece support is made of a rigid body having a tip shape that makes point contact with the workpiece, and the pressing means is composed of an elastic member arranged around the support rod. The elastic member is arranged so as to form a closed space between the elastic member and the lower surface of the work when the lower surface of the work and the supporting bar are in contact with each other, and the suction hole for decompressing the closed space is formed in the supporting bar. Provided.
(4) In (2) and (3) above, the three support rods are positioned at substantially equal intervals on a virtual circle centered on the center point of the stage.
(5) A material layer is formed on the substrate and the substrate is transmitted from the laser source while moving the laser beam from the laser source and the workpiece relative to the workpiece deformed upward or downward. In a laser lift-off method in which the material layer is peeled off from the substrate by irradiating a laser beam in a wavelength range to exceed the decomposition threshold of the material layer for the work supported at three points in a deformed state Irradiate energy level laser light.

According to the present invention, the following effects can be obtained.
(1) Since the workpiece is supported in a deformed state at three points protruding from the stage and laser lift-off processing is performed, the laser is not damaged even if the workpiece is greatly deformed. A lift-off process can be performed. Further, since the support is made at three points, the work can be supported without applying unnecessary force to the work, regardless of how the work is deformed.
(2) By providing a pressing mechanism for pressing the workpiece toward the support rod in the support mechanism that supports the workpiece, the workpiece can be securely held at three points, and the position of the workpiece is shifted as the workpiece moves. Can be prevented.
In particular, when the support rod that supports the workpiece at three points is a rigid body having a tip shape that makes point contact with the workpiece, the workpiece can be held without being vibrated when the workpiece is moved.
(3) The pressing means is composed of an elastic member arranged around the support rod, and when the work lower surface and the support rod come into contact, the elastic member and the work lower surface form a closed space, and the closed By depressurizing the space, even if the work moves, it can be held without causing any positional deviation or vibration while being maintained in point contact between the support bar and the work.
(4) The work can be stably supported by positioning the three support rods at substantially equal intervals on a virtual circle centered on the center point of the stage.

It is a conceptual diagram explaining the outline | summary of the laser lift-off process of the Example of this invention. It is a conceptual diagram which shows the structure of the optical system of the laser lift-off apparatus of the Example of this invention. It is a figure explaining a mode that a laser beam is superimposed and irradiated on a work. It is a perspective view of the stage of the Example of this invention. It is a figure which shows the 1st Example of the workpiece support body of this invention. It is a figure which shows the state holding the workpiece | work which deform | transformed using the support body of a present Example. It is a figure which shows the 2nd Example of the workpiece support body of this invention. It is a figure which shows the other structural example of the support mechanism which provided the elastic member separately from the support rod. It is a figure which shows the structural example (1) of the holding stage which hold | maintains the conventional board | substrate. It is a figure which shows the structural example (2) of the holding stage holding the conventional board | substrate.

FIG. 1 is a conceptual diagram illustrating an outline of laser lift-off processing according to an embodiment of the present invention.
In this embodiment, the laser lift-off process is performed as follows.
Three workpieces 1 on which a substrate (sapphire substrate) 1a that transmits laser light L in the ultraviolet region and a material layer 1b are laminated and a support substrate 1c is bonded are provided on the support rod 12 of the support mechanism 10 provided on the stage 20. Is supported and placed. The workpiece 1 is, for example, deformed downwardly as shown in FIG. Note that the amount of warpage of the workpiece is about 400 μm in the case of a 4-inch workpiece.
The stage 20 provided with the support mechanism 10 on which the workpiece 1 is placed is placed on a transport mechanism 2 such as a conveyor, and is transported by the transport mechanism 2 at a predetermined speed. The workpiece 1 is irradiated with a pulse laser beam L emitted from a pulse laser source (not shown) through the substrate 1a while being conveyed in the direction of arrow AB in the figure together with the stage 20.
The workpiece 1 is formed by forming a material layer 1b of a gallium nitride (GaN) compound on the surface of a substrate 1a made of sapphire. The substrate 1a only needs to be able to form a GaN-based compound material layer satisfactorily and transmit laser light having a wavelength necessary for decomposing the GaN-based compound material layer. A GaN-based compound can be used for the material layer 1b in order to efficiently output high-output blue light with low input energy. As the material layer 1b, a group III compound can be used, such as the GaN compound, indium gallium nitride (InGaN) compound, aluminum gallium nitride (AlGaN) compound, or the like.
When the material layer 1b is irradiated with the pulsed laser beam L, GaN in the material layer 1b is decomposed into gallium (Ga) and nitrogen (N ₂ ).

  The laser beam L should be appropriately selected according to the substance constituting the substrate 1a and the material layer 1b peeled from the substrate 1a. When the GaN-based compound material layer 1b is peeled from the sapphire substrate 1a, for example, a KrF (krypton fluorine) excimer laser emitting a wavelength of 248 nm can be used. The light energy (5 eV) with a laser wavelength of 248 nm is between the band gap of GaN (3.4 eV) and the band gap of sapphire (9.9 eV). Therefore, a laser beam having a wavelength of 248 nm is desirable for peeling the material layer of the GaN-based compound from the sapphire substrate.

FIG. 2 is a conceptual diagram showing the configuration of the optical system of the laser lift-off device according to the embodiment of the present invention. In the figure, a laser lift-off device is a stage having a laser source 30 for generating pulsed laser light, a laser optical system 40 for shaping the laser light into a predetermined shape, and a support mechanism 10 on which the workpiece 1 is placed. 20, a transport mechanism 2 that transports the stage 20, and a control unit 31 that controls the irradiation interval of the laser light generated by the laser source 30 and the operation of the transport mechanism 2.
The laser optical system 40 includes cylindrical lenses 41 and 42, a mirror 43 that reflects the laser light in the direction of the workpiece, a mask 44 for shaping the laser light into a predetermined shape, and the laser light L that has passed through the mask 44. And a projection lens 45 for projecting an image onto the work 1. The area and shape of the irradiation region of the pulse laser beam on the workpiece 1 can be appropriately set by the laser optical system 40.

A workpiece 1 is disposed at the tip of the laser optical system 40. The workpiece 1 is supported at three points on the support rod 12 of the support mechanism 10 provided on the stage 20. In the example of FIG. 5, the elastic member 16 provided around the support rod 12 of the support mechanism 10 and the workpiece. The work 1 is pressed in the direction of the support rod 12 by making the closed space 17 between the back surface 1 and the back surface of the support rod 12 be in contact with any one point of the support rod end portion 14.
The stage 20 is placed on the transport mechanism 2 and is transported by the transport mechanism 2. In other words, the workpiece 1 is sequentially conveyed in the directions of arrows A and B shown in FIG. When the laser beam is irradiated from the irradiation region at one end to the irradiation region at the other end, the workpiece 1 moves in the direction of arrow C in FIG. 1 and then sequentially conveyed in the directions of arrows A and B as described above. However, the laser light is sequentially irradiated to the adjacent irradiation regions.
The control unit 31 controls the pulse interval of the pulsed laser light generated by the laser source 30 so that the degree of superimposition of each laser light irradiated on the adjacent irradiation region of the workpiece 1 becomes a desired value.

The laser beam L generated from the laser source 30 is, for example, a KrF excimer laser that generates ultraviolet rays having a wavelength of 248 nm. An ArF laser or a YAG laser may be used as the laser source.
The pulsed laser light L generated by the laser source 30 passes through the cylindrical lenses 41 and 42, the mirror 43, and the mask 44, and is then projected onto the work 1 by the projection lens 45. The pulse laser beam L is applied to the interface between the substrate 1a and the material layer 1b through the substrate 1a.
By irradiating the pulse laser beam L at the interface between the substrate 1a and the material layer 1b, GaN near the interface between the material layer 1b and the substrate 1a is decomposed. In this way, the material layer 1b is peeled from the substrate 1a.

The pulse laser beam L has, for example, an irradiation region formed in a quadrangular shape, and is irradiated so that the laser beams overlap each other in regions adjacent to each other as shown in FIG. Note that the vertical axis in FIG. 3 indicates the intensity (energy value of the cross section) of the laser beam irradiated to each irradiation region of the workpiece, and the horizontal axis indicates the conveyance direction of the workpiece. L1 and L2 indicate laser beams irradiated to adjacent irradiation areas of the workpiece, and are areas where hatched areas in FIG. In addition, the same figure shows a case where the irradiation surface of the workpiece 1 is shifted from the focal position, and the cross sections of the laser beams L1 and L2 are formed in a substantially trapezoidal shape having an edge portion that gently spreads in the circumferential direction and a flat surface on the top Is shown.
The laser beams L1 and L2 are not irradiated at the same time, but the laser beam L2 is irradiated after one pulse interval from the irradiation of the laser beam L1. Further, as shown by broken lines in FIG. 3, the laser beams L1 and L2 are superimposed in an energy region exceeding a decomposition threshold VE necessary for decomposing and separating the material layer of the GaN-based compound from the sapphire substrate.
Thus, by setting the intensity of each pulsed laser beam in the region irradiated with the superimposed laser beam so as to exceed the decomposition threshold value VE, it is sufficient to peel the material layer from the substrate. Therefore, the material layer can be reliably peeled from the substrate without causing a crack in the material layer formed on the substrate.

Here, as described above, the workpiece 1 is warped by about 400 μm, for example, and the laser optical system 40 applies laser light having an energy level exceeding the decomposition threshold of the material layer to the workpiece warped as described above. It is necessary to irradiate.
Therefore, the laser optical system 40 can irradiate a laser beam having an energy level exceeding the decomposition threshold of the material layer 1b even if the distance between the projection lens 45 and the workpiece 1 varies by about 400 μm due to deformation of the workpiece 1. Specifically, when the distance between the laser optical system 40 and the workpiece 1 fluctuates by about 400 μm, the variation of the size (d in FIG. 3) of the region where the material layer 1b undergoes the decomposition reaction is about 30 μm. Use the following.
That is, when the workpiece 1 is deformed, the distance between the projection lens 45 and the workpiece 1 fluctuates when the irradiation position of the laser light relatively moves on the workpiece 1, and the irradiation surface of the workpiece is the focal position of the projection lens. The size of the region where the decomposition reaction of the crystal layer of the workpiece 1 also fluctuates, but this variation is set to about 30 μm or less, and the amount of overlap of the irradiation region is considered in consideration of the variation of 30 μm of this irradiation region. The moving condition of the stage 20 is set with the processing condition being that the amount becomes a certain amount. Thus, the entire work surface can be processed with a fixed focus position setting, that is, without adjusting the distance between the work 1 and the laser optical system 40 in real time.

Next, a specific configuration example of the stage according to the embodiment of the present invention will be described.
FIG. 4 is a perspective view of the stage according to the embodiment of the present invention.
On the stage 20, three support rods 12 that are workpiece supports constituting the support mechanism 10 are arranged. The support bar 12 is fitted into, for example, a through hole 11 provided in the stage 20, and an elastic member 16 is provided around the support bar 12 as will be described later.
The support rods 12 are arranged at substantially equal intervals on a virtual circle centered on the center point of the stage 20. By disposing the support rod 12 in this way, the workpiece can be stably supported. Further, by placing the work 1 so that the position of the center of gravity of the work 1 is substantially the center position of the stage 20, the forces applied to the three support rods 12 can be made equal.

FIG. 5 is a schematic view showing a first embodiment of a workpiece support constituting the support mechanism of the present invention. The support rod 12 is made of a hard material such as stainless steel, and the exhaust hole 13 passes through the central portion.
The support rod end portion 14 on the side on which the work is mounted is formed of a curved surface. Further, the exhaust hole 13 penetrating the center portion of the support rod 12 is bent on the support rod end portion 14 side, and an exhaust port 15 is opened on the side of the support rod end portion. That is, the exhaust port 15 is opened at a location where the surface of the workpiece 1 does not contact when the workpiece 1 is mounted.
A cylindrical elastic member 16 made of rubber or the like that is easily deformed is provided as a pressing means around the support rod end 14, and one end of the elastic member 16 surrounds the periphery of the support rod end 14. It is in close contact.
When the work 1 is mounted on the other end of the elastic member 16, the elastic member 16 is deformed as shown in FIG. 5A and is surrounded by the surface of the work 1, the support rod end 14 and the inner wall space of the elastic member 16. A closed space 17 is formed.
The closed space 17 is depressurized from the exhaust hole 13 using a compressor or the like until the work 1 and the support rod end portion 14 contact each other. Thereby, as shown in FIG.5 (b), the workpiece | work 1 is pressed on the support rod 12 direction. Since the end of the support bar 12 is formed of a curved surface, the workpiece 1 and the support bar end 14 come into contact at one point. If three support bars are used, the workpiece 1 can be fixed to the stage via the support bars 12.

  FIG. 6 shows a state in which the deformed workpiece 1 is held by using the support body of the present embodiment (the third support bar is not shown). As described above, the workpiece 1 has a three-layer structure including a substrate (sapphire substrate) 1a that transmits laser light, a material layer 1b, and a support substrate 1c. The workpiece 1 is placed on the support rod 12 so that the substrate 1a is on the upper side. Can be placed. The lower surface of the workpiece 1 is in point contact with the support rod 12 made of a rigid body, and the height from the stage 20 can be determined accurately. The support rods 12 provided at the three locations are basically set to have the same height, and the height is appropriately set in consideration of the deformation amount of the workpiece.

FIG. 7 is a schematic view showing a second embodiment of the work support constituting the support mechanism of the present invention.
The support bar 12 is made of a hard material such as stainless steel, and an exhaust hole 13 passes through the support bar 12 as shown in FIG.
The support rod end 14 on the side on which the workpiece 1 is mounted has a conical shape. Further, the exhaust hole 13 penetrating through the inside of the support rod 12 has an exhaust port 15 opened at a portion adjacent to the conical support rod end portion 14. Also in this case, the work 1 is point-contacted at the tip of the support rod end portion 14, and the work 1 is held at three points.

In the embodiment described above, the elastic member 16 is provided around the support rod end portion 14 as the pressing means, and the closed space 17 formed by the elastic member 16 and the lower surface of the workpiece 1 is decompressed to hold the workpiece 1. However, the workpiece 1 may be pressed against the support rod 12 as shown in FIG.
FIG. 8 is a diagram showing a configuration example when a means for pressing the workpiece 1 against the support bar 12 is provided separately from the support bar 12.
In the figure, the support rods 12 are provided at three places on the stage 20 as described above, and the workpiece 1 is placed thereon. A through hole 11 is provided near the center of the stage 20, and a cylindrical exhaust pipe 18 having an exhaust hole 13 is provided in the through hole 11. The exhaust pipe 18 is communicated with a compressor or the like to suck air. As a result, the space between the stage 20 and the lower surface of the work 1 is depressurized, the air pressure on the lower surface of the work 1 becomes relatively lower than the surrounding air pressure, the work 1 is pressed against the stage 20 side, and the work 1 moves. Not to be fixed.

1 Work 1a Substrate (Sapphire substrate)
1b Material layer 1c Support substrate 2 Transport mechanism 10 Support mechanism 11 Through hole 12 Support rod 13 Exhaust hole 14 Support rod end 15 Exhaust port 16 Elastic member 17 Closed space 18 Exhaust pipe 20 Stage 30 Laser source 31 Control unit 40 Laser optical system 41, 42 Cylindrical lens 43 Mirror 44 Mask 45 Projection lens

Claims (5)

A wavelength region in which a material layer is formed on a substrate and the workpiece is deformed into a convex shape or a concave shape, and the laser beam from the laser source and the workpiece are moved relative to each other while the workpiece is transmitted through the substrate. A laser lift-off device that irradiates the laser beam to peel the material layer from the substrate,
A stage provided with a support mechanism for supporting the work, the support mechanism comprising a work support for supporting the work in a deformed state at three points protruding from the stage;
The laser source irradiates the deformed workpiece with a laser beam having an energy level exceeding a decomposition threshold value of the material layer. 2. The laser lift-off device according to claim 1, wherein the workpiece support includes three support rods protruding from the stage, and the support mechanism includes a pressing unit that presses the workpiece toward the support rod. 3. . The support rod of the workpiece support is composed of a rigid body having a tip shape that makes point contact with the workpiece,
The pressing means is composed of an elastic member arranged around the support bar, and the elastic member forms a closed space between the elastic member and the work lower surface when the work lower surface and the support bar come into contact with each other. The laser lift-off device according to claim 2, wherein the support rod is provided with a suction hole for decompressing the closed space. 4. The laser lift-off device according to claim 2, wherein the three support rods are positioned at substantially equal intervals on a virtual circle centered on a center point of the stage. A wavelength region in which a material layer is formed on a substrate and the workpiece is deformed into a convex shape or a concave shape, and the laser beam from the laser source and the workpiece are moved relative to each other while the workpiece is transmitted through the substrate. A laser lift-off method in which the material layer is peeled off from the substrate by irradiating a laser beam of
A laser lift-off method characterized by irradiating the workpiece supported at three points in a deformed state with a laser beam having an energy level exceeding a decomposition threshold of the material layer.

Images