Processing device

Abstract

To improve a productivity as compared with the case where a composite substrate is transported between a laser processing device and an optical inspection device in a laser lift off.SOLUTION: A processing device comprises: a holding table; a laser beam irradiation unit that emits a pulse-like laser beam with a wavelength absorbed only by a buffer layer while passing through a first substrate against a composite substrate held by the holding table, and is for destroying a buffer region corresponded to each device in the buffer layer; a peeling unit that peels the first substrate from the composite substrate of which at least one part of the buffer layer is damaged; an imaging unit; and a controller. The controller includes a calculation part that calculates a damage success ratio that is the number of buffer regions damaged in a level that each device from the total number of the buffer regions corresponded to a plurality of devices and the first substrate are separated on the basis of an image obtained by imaging a device layer or the buffer layer after laser processing with an imaging unit.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a processing apparatus for separating a plurality of devices from a composite substrate including a first substrate, a second substrate, and a plurality of devices sandwiched between the first substrate and the second substrate, by using a pulsed laser beam. [Background technology]

[0002] In recent years, micro LED (Light Emitting Diode) displays, which are extremely small light-emitting diodes arranged in large numbers on a two-dimensional plane, have been developed. Micro LED displays have a faster response speed and lower power consumption than liquid crystal displays, and are expected to be the next-generation displays capable of projecting high-brightness, high-resolution images.

[0003] In order to mount the micro LED chips on a display panel, first, a plurality of micro LEDs including an epitaxial growth layer are formed on a first substrate (i.e., a source substrate) for forming an epitaxial growth layer, and then the plurality of micro LEDs are transferred to a second substrate (i.e., a destination substrate).

[0004] As a transfer method, a laser lift-off (LLO) process (hereinafter simply referred to as laser lift-off) is used (see, for example, Patent Document 1). In the laser lift-off, a composite substrate in which a plurality of micro LEDs are sandwiched between a first substrate and a second substrate is transported to a laser processing device, and each micro LED is irradiated with a laser beam through the first substrate, for example, to separate each micro LED from the first substrate.

[0005] However, in laser lift-off, due to defects in the laser processing, it is possible that not all of the micro LEDs are transferred to the second substrate, and multiple micro LEDs remain on the first substrate. Therefore, after the laser processing, the processed composite substrate is removed from the laser processing device and transported to an optical inspection device, and the proportion of the total number of micro LEDs that have been properly transferred to the second substrate (i.e., the transfer rate) is inspected using the optical inspection device.

[0006] However, when the composite substrate is transported between the housing of the laser processing device and the housing of the optical inspection device in this manner, the productivity decreases due to the transport between the devices. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2019-67892 A Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made in consideration of these problems, and aims to improve productivity when performing laser processing and transfer rate inspection in laser lift-off, compared to the case where a composite substrate is transported between the housing of a laser processing device and the housing of an optical inspection device. [Means for solving the problem]

[0009] According to one aspect of the present invention, there is provided a processing apparatus for separating a plurality of devices from a first substrate by using a pulsed laser beam in a composite substrate including a first substrate, a second substrate, and a plurality of devices sandwiched between the first substrate and the second substrate, the processing apparatus comprising: a device layer including the plurality of devices fixed to a first surface side of the first substrate via a buffer layer; and a fixed surface of the device layer opposite the buffer layer fixed to a second surface of the second substrate, the processing apparatus comprising: a holding table for holding a third surface of the second substrate opposite the second surface; and a laser oscillator, the processing apparatus irradiating the composite substrate held by the holding table with the laser beam in a direction proceeding from the first substrate to the second substrate, the laser beam having a wavelength that is transmitted through the first substrate but is absorbed by the buffer layer, to separate the devices from the buffer layer by using a pulsed laser beam. a controller having a processor and a memory, and controlling the holding table, the laser beam irradiation unit, the peeling unit, and the imaging unit, wherein the controller has a calculation section that calculates a destruction success rate, which is the number of buffer regions that were destroyed to the extent that the devices and the first substrate were separated out of the total number of buffer regions corresponding to the plurality of devices, or a destruction failure rate, which is the number of buffer regions that were not destroyed to the extent that the devices and the first substrate were separated out of the total number, based on an image obtained by imaging the device layer or the buffer layer after laser processing by the laser beam irradiation unit with the imaging unit.

[0010] Preferably, the controller further has a post-processing judgment unit which judges whether a result of the laser processing is acceptable or not based on the destruction success rate or the destruction failure rate calculated by the calculation unit.

[0011] Also, preferably, if the judgment result at the post-processing judgment section is a failure, the controller controls the laser beam irradiation unit to irradiate the laser beam again so as to destroy the remaining buffer region in contact with one or more devices.

[0012] Also, preferably, after the laser beam irradiation unit irradiates the laser beam onto the buffer region corresponding to each device and the peeling unit peels off the first substrate, the calculation unit calculates the destruction success rate or the destruction failure rate based on an image obtained by imaging the second surface side of the second substrate with the imaging unit, and if the judgment result by the post-processing judgment unit based on the destruction success rate or the destruction failure rate is unacceptable, the controller returns the first substrate to its original position so that it overlaps the second substrate, and then controls the laser beam irradiation unit to re-irradiate the laser beam so as to destroy the remaining buffer region in a manner that contacts the one or more devices.

[0013] Furthermore, preferably, after the laser beam irradiation unit irradiates the laser beam onto the buffer region corresponding to each device and the peeling unit peels off the first substrate, the calculation unit calculates the destruction success rate or the destruction failure rate based on an image obtained by imaging the first surface side of the first substrate with an imaging unit different from the imaging unit, and if the judgment result by the post-processing judgment unit based on the destruction success rate or the destruction failure rate is unacceptable, the controller returns the first substrate to its original position so that the first substrate overlaps the second substrate, and then controls the laser beam irradiation unit to re-irradiate the laser beam so as to destroy the remaining buffer region in a manner that contacts the one or more devices.

[0014] Furthermore, preferably, after the laser beam irradiation unit irradiates the buffer region corresponding to each device with the laser beam and before the peeling unit peels off the first substrate, the calculation unit calculates the destruction success rate or the destruction failure rate based on an image obtained by imaging the first surface side of the first substrate with the imaging unit, and if the judgment result by the post-processing judgment unit based on the destruction success rate or the destruction failure rate is unsatisfactory, the controller controls the laser beam irradiation unit to irradiate the laser beam again through the first substrate so as to destroy the remaining buffer region in a manner contacting the one or more devices.

[0015] In addition, preferably, the controller further includes a pre-processing judgment section which judges whether or not the plurality of devices are formed normally based on an image obtained by imaging the device layer with the imaging unit through the first substrate of the composite substrate held on the holding table before the laser beam is irradiated to the composite substrate by the laser beam irradiation unit.

[0016] In a preferred embodiment, the processing device further includes a display device, and the controller further includes a processing condition change unit that performs laser processing under different processing conditions set by an operator for each of a plurality of processing regions constituting the first surface of the first substrate, and after the laser beam is irradiated onto the buffer layer under processing conditions specified by the processing condition change unit for each of the plurality of processing regions, the calculation unit calculates the success rate of destruction or the failure rate of destruction for each processing region based on an image obtained by capturing an image of the device layer or the buffer layer with the imaging unit, and the controller causes the display device to display the different processing conditions and the success rate of destruction or the failure rate of destruction for each processing region calculated by the calculation unit.

[0017] In addition, preferably, after the laser beam irradiation unit irradiates the buffer region corresponding to each device with the laser beam under predetermined processing conditions, the controller associates the destruction success rate or the destruction failure rate calculated by the calculation unit based on the image obtained by imaging the device layer or the buffer layer with the imaging unit with the predetermined processing conditions and stores them in the memory, and the processing device further includes an alarm device for notifying an operator that the destruction success rate has fallen below the predetermined threshold or that the destruction failure rate has exceeded the second threshold when the destruction success rate obtained by performing laser processing under the predetermined processing conditions falls below a first threshold or when the destruction failure rate exceeds a second threshold. Effect of the Invention

[0018] In a processing device according to one embodiment of the present invention, an imaging unit captures an image of a device layer or a buffer layer that has been subjected to laser processing, and a calculation section of a controller calculates the rate of successful destruction of the buffer region or the rate of unsuccessful destruction of the buffer region based on the obtained image.

[0019] Therefore, when performing the laser lift-off, the laser processing and the calculation of the transfer rate can be performed in the processing device. Therefore, the time required for transporting the composite substrate can be reduced compared to the case where the composite substrate is transported between the housing of the laser processing device and the housing of the optical inspection device, and therefore the productivity can be improved. Furthermore, reprocessing can be performed in the processing device when the transfer rate is low. [Brief description of the drawings]

[0020] [Figure 1] FIG. 2 is a cross-sectional view of a composite substrate. [Diagram 2] FIG. 1 is a perspective view showing an example of a processing apparatus. [Diagram 3] FIG. 3(A) is a diagram showing an outline of a laser beam irradiation unit in a plan view, and FIG. 3(B) is a diagram showing a laser processing step. [Figure 4] FIG. 4(A) is a diagram showing an outline of the peeling unit as seen from the side, and FIG. 4(B) is a diagram showing the peeling step. [Diagram 5] FIG. 2 is a block diagram for explaining the function of a controller. [Figure 6] FIG. 4 is a flow diagram of laser lift-off in the first embodiment. [Figure 7] FIG. 13 is a diagram showing an imaging step after a peeling step. [Figure 8] FIG. 8(A) shows six devices in a plan view before the laser processing process, FIG. 8(B) shows an example in which six devices have been successfully transferred, and FIG. 8(C) shows an example in which one device has been successfully transferred but five devices have not been transferred. [Figure 9] FIG. 13 is a diagram showing a returning step of returning the peeled first substrate to its original position. [Figure 10] FIG. 13 illustrates a laser beam reprocessing process. [Figure 11] FIG. 11 is a flow diagram of laser lift-off in the second embodiment. [Figure 12] 13 is a diagram showing a state in which the first substrate is imaged after a peeling step in the second embodiment. FIG. [Figure 13] FIG. 11 is a flow diagram of laser lift-off in the third embodiment. [Figure 14] 13A to 13C are diagrams illustrating an imaging process in the third embodiment. [Figure 15] FIG. 13 is a flow diagram of laser lift-off in the fourth embodiment. [Figure 16] FIG. 16(A) is a diagram showing a pre-processing imaging step S4 in the fourth embodiment, and FIG. 16(B) is a block diagram for explaining the function of a controller in the fourth embodiment. [Figure 17] FIG. 17(A) is a block diagram for explaining the function of controller 82 in the first modified example, and FIG. 17(B) is a plan view of a composite substrate for showing the processing conditions set for each processing region. [Figure 18] FIG. 13 is a diagram showing an example of a screen display showing a destruction success rate and a processing time for each processing condition. [Figure 19]FIG. 19(A) is a diagram showing an example of a screen display when the destruction success rate falls below a first threshold, and FIG. 19(B) is a diagram showing an example of a screen display when the destruction failure rate exceeds a second threshold. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] (First embodiment) An embodiment according to one aspect of the present invention will be described with reference to the accompanying drawings. First, with reference to Fig. 1, a composite substrate 11 to be processed in laser lift-off using a processing device 2 (see Fig. 2) will be described.

[0022] 1 is a cross-sectional view of composite substrate 11. Composite substrate 11 has a rectangular plate-shaped first substrate 13 made of sapphire. First substrates 13 are located on opposite sides to each other in the thickness direction of first substrate 13, and each has a rectangular front surface (first surface) 13a and back surface 13b.

[0023] In this specification, the terms "front" and "back" are used for the sake of convenience, and the front side may be referred to as "one side" and the back side as "the other side." A buffer layer 17 including a plurality of island-shaped buffer regions 15 is provided on the front side 13a of the first substrate 13.

[0024] The buffer regions 15 are formed by dividing the buffer layer 17 into a lattice shape. The buffer regions 15 have approximately the same thickness, and are arranged on the surface 13a of the first substrate 13 at approximately equal intervals.

[0025] Each buffer region 15 has a substrate fixing surface 15a and a device fixing surface 15b located opposite to each other in the thickness direction of the buffer region 15. The substrate fixing surface 15a of the buffer region 15 contacts the surface 13a of the first substrate 13.

[0026] The buffer region 15 has a function of reducing the degree of lattice mismatch between the first substrate 13 made of, for example, sapphire and one device 19 formed in contact with one device fixing surface 15b.

[0027] The material of the buffer region 15 is determined depending on the device 19, and may be, for example, gallium nitride (GaN), aluminum gallium nitride (AlGaN), etc. In contact with one buffer region 15, one device 19 is formed.

[0028] More specifically, the compound semiconductor layer constituting the device 19 is formed by epitaxial growth in contact with the device fixing surface 15b of the buffer region 15. That is, a growth initiation surface 19a at which epitaxial growth starts in the device 19 is in contact with the device fixing surface 15b of the buffer region 15.

[0029] In this manner, the devices 19 are fixed to the front surface 13a side of the first substrate 13 via the buffer layer 17. Each device 19 has a growth start surface 19a and a fixed surface 19b located on opposite sides to each other in the thickness direction of the device 19.

[0030] Since each device 19 has approximately the same thickness and can be regarded as approximately one layer in contact with the buffer layer 17, the layer including the multiple devices 19 is referred to as a device layer 21 in this embodiment.

[0031] A plurality of devices 19 are formed two-dimensionally at substantially equal intervals in accordance with the plurality of buffer regions 15. The devices 19 in this embodiment are micro LEDs. The devices 19 include a compound semiconductor formed of a combination of a group III element and a group V element.

[0032] Compound semiconductors constituting device 19 include the above-mentioned GaN, gallium phosphide (GaP), indium gallium phosphide (GaInP), indium gallium arsenide (GaInAs), indium gallium arsenide phosphide (InGaAsP), indium phosphide (InP), indium nitride (InN), indium arsenide (InAs), aluminum nitride (AlN), and aluminum gallium arsenide (AlGaAs).

[0033] Further, the devices 19 have a first electrode serving as an anode and a second electrode serving as a cathode (both not shown). The laminate of the first substrate 13, the buffer layer 17 and the device layer 21 is fixed to the second substrate 25 via a bonding material 23 so that the multiple devices 19 are sandwiched between the first substrate 13 and the second substrate 25.

[0034] The bonding material 23 is formed of an alloy such as silver-tin (AgSn) or gold-tin (AuSn), a pure metal such as gold (Au), platinum (Pt), chromium (Cr), indium (In), or palladium (Pd), or an organic material such as resin.

[0035] The second substrate 25 is a silicon (Si) single crystal substrate having approximately the same rectangular plate shape as the first substrate 13. However, the second substrate 25 may be a copper (Cu) substrate, a molybdenum (Mo) substrate, or the like having the same shape.

[0036] The second substrates 25 are located on opposite sides in the thickness direction of the second substrate 25, and each has a rectangular front surface (second surface) 25a and a rear surface (third surface) 25b. A bonding material 23 having a substantially uniform thickness is formed on the entire front surface 25a of the second substrate 25.

[0037] The bonding material 23 is in contact with the fixed surface 19b of each device 19 located on the opposite side of the buffer layer 17 in the device layer 21. That is, the fixed surface 19b of each device 19 is fixed to the surface 25a of the second substrate 25 via the bonding material 23.

[0038] In this manner, the device layer 21 is sandwiched and fixed between the first substrate 13 and the second substrate 25 to form the composite substrate 11. Next, a processing device 2 for separating the plurality of devices 19 in the composite substrate 11 from the first substrate 13 by using a laser beam L will be described.

[0039] Fig. 2 is a perspective view showing an example of the processing device 2. The X-axis direction (processing feed direction), the Y-axis direction (indexing feed direction), and the Z-axis direction (up-down direction, vertical direction) shown in Fig. 2 are mutually orthogonal. The processing device 2 has a base 4 that supports each component.

[0040] A ball screw type movement mechanism 6 is provided on the upper surface of the base 4. The movement mechanism 6 has a pair of Y-axis guide rails 8 fixed to the upper surface of the base 4. The pair of Y-axis guide rails 8 are arranged along the Y-axis direction, and a Y-axis direction movement plate 10 is fixed to the upper portion thereof so as to be slidable along the Y-axis direction.

[0041] The Y-axis direction moving plate 10 has a rectangular plate shape in which the length in the X-axis direction is longer than the length in the Y-axis direction. A nut portion (not shown) is fixed to the lower surface of the Y-axis direction moving plate 10, and a screw shaft 12 is rotatably connected to the nut portion by using a ball (not shown).

[0042] The screw shaft 12 is disposed approximately parallel to the Y-axis direction. A driving source 14 such as a stepping motor for rotating the screw shaft 12 is connected to one end of the screw shaft 12. When the driving source 14 is operated, the Y-axis direction moving plate 10 moves along the Y-axis direction.

[0043] A pair of X-axis guide rails 16 are fixed to the upper surface of the Y-axis direction moving plate 10. The pair of X-axis guide rails 16 are arranged along the X-axis direction, and an X-axis direction moving plate 18 is fixed to the upper portion thereof so as to be slidable along the X-axis direction.

[0044] A nut portion (not shown) is fixed to the lower surface side of the X-axis direction moving plate 18, and a screw shaft 20 is rotatably connected to the nut portion by using balls (not shown). The screw shaft 20 is disposed substantially parallel to the X-axis direction. A drive source 22 such as a stepping motor for rotating the screw shaft 20 is connected to one end of the screw shaft 20.

[0045] When the driving source 22 is operated, the X-axis direction moving plate 18 moves along the X-axis direction. A cylindrical table base 24 is provided on the upper surface side of the X-axis direction moving plate 18. A rotation driving source (not shown) such as a motor is provided inside the table base 24.

[0046] A disk-shaped chuck table (holding table) 26 is disposed on the top of the table base 24, and the chuck table 26 can be rotated around a predetermined rotation axis parallel to the Z-axis direction by the above-mentioned rotation drive source.

[0047] The chuck table 26 has a disk-shaped frame made of non-porous metal. A disk-shaped recess is formed in the center of the upper surface of the frame. A disk-shaped porous plate made of porous ceramics is fixed in this recess.

[0048] A predetermined flow path (not shown) is formed in the frame. A suction source (not shown) such as a vacuum pump is connected to the frame via a duct, a pipe, etc. that forms a gas flow path (not shown). An opening / closing valve (not shown) such as an electromagnetic valve is provided in the middle of the gas flow path that connects the frame and the suction source.

[0049] When the on-off valve is opened, negative pressure is transmitted from the suction source to the upper surface of the porous plate. The annular upper surface of the frame and the circular upper surface of the porous plate are substantially flush with each other, and function as a substantially flat holding surface 26a for holding the composite substrate 11 by suction.

[0050] The holding surface 26a is disposed approximately parallel to the XY plane. A plurality of (four in this embodiment) clamp units 26b are provided on the outer periphery of the chuck table 26 at approximately equal intervals along the circumferential direction of the chuck table 26.

[0051] Each clamp unit 26b is an air actuator including a vane (not shown) that is rotationally driven by air. The vane is connected to a metal frame pressing part, and the frame pressing part opens and closes by rotating the vane.

[0052] When the composite substrate 11 is held by suction on the holding surface 26a, the frame pressing portion is opened, and then a conveying device (not shown) places the composite substrate unit 31, in which the composite substrate 11 is supported by a metal annular frame 29 via a circular tape 27, on the holding surface 26a (see FIG. 3(B)).

[0053] Thereafter, the frame pressing portion is closed, whereby frame 29 is sandwiched and spatially fixed by clamp unit 26b, and rear surface 25b of second substrate 25 is suction-held by holding surface 26a via tape 27.

[0054] A first support structure 30 is provided in a predetermined region of the base 4 located behind the movement mechanism 6 (one side in the Y-axis direction). A ball screw type Z-axis movement mechanism 32 is provided on one side of the first support structure 30 along the YZ plane.

[0055] The Z-axis direction movement mechanism 32 has a pair of Z-axis guide rails 34. Note that one Z-axis guide rail 34 is shown in Fig. 2. The pair of Z-axis guide rails 34 are fixed to one side surface of the first support structure 30.

[0056] The pair of Z-axis guide rails 34 are disposed along the Z-axis direction, and a Z-axis direction moving plate 36 is fixed to the pair of Z-axis guide rails 34 so as to be slidable along the Z-axis direction. A nut portion (not shown) is fixed to the rear surface of the Z-axis direction moving plate 36, and a screw shaft (not shown) is rotatably connected to the nut portion by using a ball (not shown).

[0057] The screw shaft of the Z-axis direction moving mechanism 32 is disposed approximately parallel to the Z-axis direction. A driving source 38 such as a stepping motor for rotating the screw shaft is connected to the upper end of the screw shaft. When the driving source 38 is operated, the Z-axis direction moving plate 36 moves along the Z-axis direction.

[0058] A support 40 is fixed to the surface of the Z-axis direction moving plate 36. The support 40 supports a laser beam irradiation unit 42. The laser beam irradiation unit 42 has a cylindrical housing 44. The housing 44 is movable along the Z-axis direction by the Z-axis direction moving mechanism 32.

[0059] In this embodiment, the laser oscillator 46 is provided in the housing 44. However, the laser oscillator 46 may be provided in an optical box (not shown) placed on the base 4, instead of in the housing 44 supported by the Z-axis direction moving mechanism 32.

[0060] The laser oscillator 46 has, for example, a Nd:YVO4 crystal as a laser medium, an excitation light source (not shown) such as a lamp that irradiates the laser medium with excitation light, and a Q switch (not shown) that controls the timing at which the laser beam L is emitted.

[0061] The laser oscillator 46 generates a pulsed laser beam L having a predetermined wavelength (e.g., 266 nm) that is transmitted through the first substrate 13 but absorbed by the buffer layer 17. In Fig. 2, the laser beam L in the housing 44 is indicated by a dashed arrow. The transmittance of the laser beam L through the first substrate 13 is, for example, 70% or more and 90% or less (i.e., not 100%).

[0062] An irradiation head 48 is provided at the tip of the housing 44. The irradiation head 48 has a galvano scanner 50 for moving the focal point of the laser beam L within the XY plane with respect to the composite substrate 11 held by suction on the holding surface 26a.

[0063] 3(A) is a plan view showing an outline of the laser beam irradiation unit 42. The galvano scanner 50 has a first mirror 50a that moves the focal point along the X-axis direction, and a second mirror 50b that moves the focal point along the Y-axis direction.

[0064] The first mirror 50a has a rotation axis arranged along the Z-axis direction, and the reflecting surface of the first mirror 50a is configured to be rotatable within a predetermined angle range on the X-Y plane. The second mirror 50b has a rotation axis arranged along the X-axis direction, and the reflecting surface of the second mirror 50b is configured to be rotatable within a predetermined angle range on the Y-Z plane.

[0065] The laser beam L reflected by the galvano scanner 50 passes through a telecentric fθ lens 52 and is irradiated onto the composite substrate 11 in a direction traveling from the first substrate 13 to the second substrate 25 .

[0066] Fig. 3(B) is a diagram showing the laser processing step S10 (see Fig. 6 for reference symbol S10). Note that in Fig. 3(B) and subsequent figures, hatching of composite substrate 11 is omitted for ease of viewing the figures.

[0067] The laser beam L transmitted through the telecentric fθ lens 52 is irradiated substantially perpendicularly onto the composite substrate 11. The focal point of the laser beam L irradiated onto the composite substrate 11 has substantially the same diameter regardless of the position within the XY plane.

[0068] In this embodiment, the galvano scanner 50 moves the light collection point in a spiral shape so as to approach the center of rotation (or move away from the center of rotation) as it rotates.

[0069] After the laser beam L passes through the first substrate 13, it is absorbed in the buffer region 15, whereby an ablation process is performed on the buffer region 15, and as a result, the buffer region 15 corresponding to each device 19 is destroyed.

[0070] Returning now to Fig. 2, a microscope camera unit (imaging unit) 54 is provided on the side surface near the tip of the housing 44. The microscope camera unit 54 of this embodiment includes a condenser lens (not shown) and a solid-state imaging element (not shown) capable of photoelectrically converting light in the visible light band.

[0071] A solid-state imaging device is a two-dimensional image sensor in which photoelectric conversion elements are arranged two-dimensionally, and more specifically, is a complementary metal-oxide-semiconductor (CMOS) image sensor, a charge-coupled device (CCD) image sensor, or the like.

[0072] The microscope camera unit 54 of this embodiment captures an image of the device layer 21 or the buffer layer 17 after laser processing by the laser beam irradiation unit 42 .

[0073] The image obtained by imaging is used in the controller 82 described later to calculate the number of destroyed buffer areas 15 relative to the total number of buffer areas 15 (i.e., the destruction success rate), or the number of undestroyed buffer areas 15 relative to the total number of buffer areas 15 (i.e., the destruction failure rate).

[0074] After performing laser processing on composite substrate 11 to destroy at least a portion of buffer layer 17, chuck table 26 moves along the X-axis direction to directly below peeling unit 56. Then, peeling unit 56 peels off first substrate 13 from composite substrate 11.

[0075] A second support structure 60 is provided behind the movement mechanism 6 and adjacent to the first support structure 30 in the X-axis direction. A ball screw type Z-axis movement mechanism 62 is provided on one side of the second support structure 60 along the YZ plane.

[0076] The Z-axis direction movement mechanism 62 has a pair of Z-axis guide rails 64. Note that one Z-axis guide rail 64 is shown in Fig. 2. The pair of Z-axis guide rails 64 are fixed to one side surface of the second support structure 60.

[0077] The pair of Z-axis guide rails 64 are disposed along the Z-axis direction, and a Z-axis direction moving plate 66 is fixed to the pair of Z-axis guide rails 64 so as to be slidable along the Z-axis direction. A nut portion (not shown) is fixed to the rear surface of the Z-axis direction moving plate 66, and a screw shaft (not shown) is rotatably connected to the nut portion by using a ball (not shown).

[0078] The screw shaft of the Z-axis direction moving mechanism 62 is disposed approximately parallel to the Z-axis direction. A driving source 68 such as a stepping motor for rotating the screw shaft is connected to the upper end of the screw shaft. When the driving source 68 is operated, the Z-axis direction moving plate 66 moves along the Z-axis direction. A support 70 is fixed to the surface of the Z-axis direction moving plate 66.

[0079] The support 70 supports a cylindrical housing 72. The housing 72 is movable along the Z-axis direction by the Z-axis direction movement mechanism 62. The above-mentioned peeling unit 56 is fixed to the tip of the housing 72.

[0080] The peeling unit 56 will now be described with reference to Fig. 4(A). Fig. 4(A) is a side view showing an outline of the peeling unit 56. The peeling unit 56 has a columnar portion 58a fixed to the housing 72.

[0081] The top surface of a disk-shaped head portion 58b is fixed to the bottom of the cylindrical portion 58a. A plurality of suction pads 58c are provided on the bottom surface of the head portion 58b. In this embodiment, for example, four suction pads 58c are provided on the head portion 58b, but the number of suction pads 58c may be two or more.

[0082] The four suction pads 58c are each equidistant from the center of the bottom surface of the head portion 58b and are arranged at approximately equal intervals in the circumferential direction of the head portion 58b. A negative pressure is supplied to each suction pad 58c from a suction source (not shown) such as a vacuum pump.

[0083] A push-up mechanism (not shown) is provided below the peeling unit 56. The push-up mechanism applies an upward external force to the first substrate 13 by pushing up one side of the first substrate 13 while the composite substrate 11 is held by suction on the holding surface 26a, using the principle of a lever. This promotes the destruction of the buffer region 15, and reduces the bonding force between the device 19 and the first substrate 13.

[0084] However, the force that the push-up mechanism applies to the composite substrate 11 is not strong enough to destroy the unbroken buffer region 15. In Fig. 4(A), the destroyed buffer region 15 is shown in black, and the unbroken buffer region 15 is shown in white.

[0085] For example, after a push-up mechanism pushes up each side of the first substrate 13, the suction pads 58c suck and hold the first substrate 13 by utilizing negative pressure. Fig. 4(B) is a diagram showing the peeling step S20 (see Fig. 6 for reference symbol S20). Note that, for convenience of explanation, a number of devices 19 present in the depth direction of the page are omitted in Fig. 4(B).

[0086] While the second substrate 25 continues to be held by suction on the holding surface 26a via the tape 27, when the head portion 58b, which is holding the first substrate 13 by suction, is raised, the first substrate 13 is peeled off from the composite substrate 11.

[0087] Instead of or together with the push-up mechanism, an ultrasonic application unit (not shown) may apply ultrasonic waves (i.e., elastic vibration waves in a frequency band exceeding 20 kHz) to the buffer region 15 to apply an external force. When applying ultrasonic waves, the ultrasonic application unit applies ultrasonic waves to the buffer layer 17 before the first substrate 13 is sucked and held by the suction pad 58c.

[0088] The ultrasonic wave application unit has, for example, a piezoelectric element and a nozzle, and sprays liquid such as pure water to which ultrasonic waves are applied by the piezoelectric element from the nozzle onto the first substrate 13. Alternatively, the ultrasonic wave application unit may have a horn connected to the piezoelectric element and a nozzle.

[0089] In this case, ultrasonic waves may be applied from the horn to first substrate 13 while liquid such as pure water flows between the horn and first substrate 13 with the horn in close proximity to first substrate 13. Alternatively, ultrasonic waves may be applied from the horn to first substrate 13 without passing through liquid with the horn connected to a piezoelectric element in close proximity to first substrate 13.

[0090] The ultrasonic wave application unit first applies an external force by using ultrasonic waves to a localized region having a diameter of about 5 mm to 50 mm on the first substrate 13. Next, the ultrasonic wave application unit applies an external force to another region of the first substrate 13 by moving the nozzle or horn and the chuck table 26 relatively.

[0091] In this way, the destruction of the buffer region 15 can be accelerated by gradually expanding the area to which the external force is applied on the rear surface 13b of the first substrate 13. However, the external force caused by the ultrasonic waves is not strong enough to destroy the buffer region 15 that is not destroyed.

[0092] 2, a description will now be given of other elements of the processing device 2. The above-mentioned moving mechanism 6, chuck table 26, first support structure 30, second support structure 60, etc. are covered from above and sides by a housing 4a composed of multiple panels.

[0093] A touch panel 74 is provided on the front side (the other side in the Y-axis direction) of the housing 4a. The touch panel 74 has a liquid crystal display and functions as a display device that displays images obtained by the microscope camera unit 54, processing conditions, messages, etc., and as an input device for the operator to input instructions.

[0094] The touch panel 74 also functions as a notification device 80 that notifies the operator of the result of the laser processing. For example, if the above-mentioned destruction success rate falls below the first threshold value as a result of the laser processing, or if the destruction failure rate (= 1 - destruction success rate) exceeds the second threshold value, the touch panel 74 notifies the operator of that fact by displaying it on the screen.

[0095] A speaker 76 and a rotating light 78 are provided on the top surface of the housing 4a. The speaker 76 is configured to emit voice, electronic sounds, alarm sounds, etc. These voices, etc. are stored in the processing device 2 in advance.

[0096] For example, when the rate of successful destruction falls below the first threshold or the rate of unsuccessful destruction exceeds the second threshold as a result of the laser processing, the speaker 76 notifies the worker of this by voice or the like. That is, the speaker 76 also functions as the notification device 80.

[0097] The rotating light 78 is a so-called patrol lamp, and is made up of a red lamp, a yellow lamp, a green lamp, and a blue lamp stacked from top to bottom in that order. The rotating light 78 lights up or flashes in a predetermined color according to the result of the laser processing.

[0098] For example, if, as a result of the laser processing, the above-mentioned destruction success rate falls below the first threshold value, or if the destruction failure rate exceeds the second threshold value, the rotating light 78 will notify the operator of this by emitting a color.

[0099] For example, the rotating light 78 notifies the user that the result of the laser processing is favorable by lighting a blue lamp, and notifies the user that the result of the laser processing is unfavorable by flashing a red lamp. In other words, the rotating light 78 also functions as a notification device 80.

[0100] The operations of the chuck table 26, Z-axis direction moving mechanism 32, laser beam irradiation unit 42, microscope camera unit 54, peeling unit 56, Z-axis direction moving mechanism 62, touch panel 74, speaker 76, rotating light 78, etc. are controlled by a controller 82.

[0101] In controlling the operation of the chuck table 26, the controller 82 also controls the operations of the moving mechanism 6, the rotation drive source in the table base 24, the on-off valve connected to the vacuum pump, the clamp unit 26b, and the like.

[0102] The controller 82 is configured by a computer having a processor 84 represented by a CPU (Central Processing Unit), for example, and a memory 86. The memory 86 includes a main storage device such as a DRAM (Dynamic Random Access Memory) and an auxiliary storage device such as a flash memory.

[0103] The auxiliary storage device stores software including a predetermined program. The functions of the controller 82 are realized by operating the processor 84 in accordance with this software.

[0104] Next, the function of the controller 82 shown in Fig. 5 will be described with reference to the flow diagram shown in Fig. 6. Fig. 5 is a block diagram for explaining the function of the controller 82, and Fig. 6 is a flow diagram of the laser lift-off in the first embodiment.

[0105] In the laser lift-off, first, the chuck table 26 and the laser beam irradiation unit 42 are controlled to irradiate the buffer regions 15 corresponding to each device 19 with a laser beam L (see FIG. 3(B)). As a result, each buffer region 15 is destroyed by ablation processing (laser processing step S10). An example of processing conditions is shown below.

[0106] Wavelength: 266nm Repetition frequency: 50kHz Average output: 0.12W Focus point movement speed: 600mm / s Diameter of the focal point: 70μm

[0107] After the laser processing step S10 (i.e., laser processing), the chuck table 26 is moved to directly below the peeling unit 56. Then, the push-up mechanism and / or the ultrasonic application unit are operated to apply an external force to the composite substrate 11, thereby reducing the bonding force of the destroyed buffer region 15.

[0108] Thereafter, the peeling unit 56, the Z-axis direction moving mechanism 62, etc. are controlled to peel off the first substrate 13 from the composite substrate 11 (peeling step S20) (see FIGS. 4(A) and 4(B)). At this time, the entire buffer layer 17 may not be completely destroyed.

[0109] Since the bonding strength between the first substrate 13 and the device 19 by the undestroyed buffer region 15 is stronger than the bonding strength between the second substrate 25 and the device 19 by the bonding material 23, the device 19 in contact with the undestroyed buffer region 15 remains on the first substrate 13 in the peeling process S20.

[0110] In this embodiment, after the first substrate 13 is peeled off, the chuck table 26 is moved below the microscope camera unit 54, and the microscope camera unit 54 captures an image of the front surface 25a side of the second substrate 25. This results in an image 54a (see FIG. 5) (imaging step S30).

[0111] Fig. 7 is a diagram showing the imaging step S30 after the peeling step S20. For convenience of explanation, in Fig. 7, similarly to Fig. 4(B), a plurality of devices 19 present in the depth direction of the page are omitted.

[0112] In the imaging process S30, the microscope camera unit 54 images a specified area narrower than the surface 25a of the second substrate 25, and then the chuck table 26 is moved along the X-axis or Y-axis direction so that the microscope camera unit 54 images another area.

[0113] By acquiring a plurality of images 54a in this manner, the entire range of the surface 25a of the second substrate 25 is imaged. The calculation unit 82a of the controller 82 has an image linking function that creates an entire image of the surface 25a by arranging the acquired individual images 54a in a tiled shape and linking them.

[0114] The calculation unit 82a has image processing functions such as edge detection and object detection, and performs image processing on the entire image after creating the entire image. As a result, the calculation unit 82a highlights the outlines of devices 19 that have outlines that match predetermined shapes (e.g., substantially rectangular) and vertical and horizontal sizes (e.g., 15 μm vertical and 10 μm horizontal) (i.e., satisfy the specified conditions) in the display area of ​​the touch panel 74 (see FIG. 8(B)).

[0115] The calculation unit 82a further counts the number of devices 19 that satisfy the specified condition. The number of devices 19 that satisfy the specified condition with respect to the total number of buffer regions 15 indicates the ratio of devices 19 that have been transferred from the first substrate 13 to the second substrate 25 (i.e., the transfer success rate).

[0116] Successful transfer means that the buffer regions 15 are properly destroyed. Therefore, the transfer success rate can be regarded as a destruction success rate, which is the number of buffer regions 15 that are destroyed to such an extent that the devices 19 and the first substrate 13 are separated from each other among the buffer regions 15 corresponding to the multiple devices 19.

[0117] The calculation unit 82a of this embodiment calculates the destruction success rate based on the whole image (calculation step S40). Note that since the complementary event of destruction success is destruction failure (i.e., the sum of the destruction success rate and the destruction failure rate is 1), the calculation unit 82a may calculate the destruction failure rate in the calculation step S40.

[0118] In other words, the calculation unit 82a may calculate, based on the overall image, a failure destruction rate, which is the number of buffer regions 15 corresponding to a plurality of devices 19 that were not destroyed to the extent that the devices 19 and the first substrate 13 were separated.

[0119] In the following explanation, the destruction success rate is basically used to calculate the transfer success rate, but the destruction failure rate may also be used. Since one of the destruction success rate and the destruction failure rate can be calculated and then the other can be calculated by subtracting the one from 1, there is no essential difference whether the destruction success rate or the destruction failure rate is used.

[0120] Such a calculation unit 82a can be realized by executing a first program stored in an auxiliary storage device by the processor 84. Note that since the calculation unit 82a can calculate the destruction success rate by image processing such as object detection, even if the vertical and horizontal orientations of the image 54a are inclined with respect to the X-axis direction (or Y-axis direction) on the XY plane, no problem occurs in calculating the destruction success rate and / or destruction failure rate.

[0121] Fig. 8(A) is a diagram showing six devices 19 in a plan view before the laser processing step S10. Fig. 8(A) shows the initial state of the devices 19 before the laser processing step S10.

[0122] Figure 8(A) corresponds to a portion of an overall image obtained, for example, by imaging a composite substrate 11 in which the back surface 25b of the second substrate 25 is suction-held by the holding surface 26a from above so as to pass through the first substrate 13.

[0123] FIG. 8(B) is a portion of the result of image processing applied to the overall image obtained in the imaging process S30 after the laser processing process S10 and the peeling process S20, and shows an example in which the buffer region 15 has been destroyed and six devices 19 have been successfully transferred.

[0124] FIG. 8(C) is a portion of the results of image processing applied to the overall image obtained in the imaging process S30 after the laser processing process S10 and the peeling process S20, and shows an example in which the transfer of one device 19 is successful but the transfer of five devices 19 is unsuccessful.

[0125] In Fig. 8(C), four devices 19 in the first and second columns only partially remain on the second substrate 25. Also, in Fig. 8(C), one device 19 in the first row and third column does not remain at all on the second substrate 25 (indicated by a dashed line in Fig. 8(C)).

[0126] After the calculation step S40, the post-processing determination unit 82b of the controller 82 determines whether the result of the laser processing is acceptable or not based on the destruction success rate (or destruction failure rate) calculated by the calculation unit 82a.

[0127] A threshold value for the destruction success rate (e.g., 99%) is stored in advance in the memory 86, and the post-processing judgment unit 82b reads out this threshold value from the memory 86 and compares the destruction success rate calculated by the calculation unit 82a with this threshold value.

[0128] If the destruction success rate is equal to or greater than the threshold value, the post-processing judgment unit 82b judges that the result of the laser processing is acceptable (YES in S60). If the judgment result is acceptable, the flow ends.

[0129] On the other hand, if the destruction success rate is less than the threshold (i.e., below the threshold), the post-processing judgment unit 82b judges that the result of the laser processing is unacceptable (NO in S60). The post-processing judgment unit 82b can be realized by causing the processor 84 to execute a second program stored in the auxiliary storage device.

[0130] Of course, a threshold value (for example, 1%) of the destruction failure rate may be stored in advance in the memory 86. In this case, the post-processing determination unit 82b compares this threshold value with the destruction failure rate calculated by the calculation unit 82a.

[0131] If the judgment result is a failure, the controller 82 returns the chuck table 26 to directly below the peeling unit 56, and further returns the first substrate 13 accurately to its original position before the peeling process S20 so that the first substrate 13 overlaps the second substrate 25 in the Z-axis direction (returning process S70).

[0132] Fig. 9 is a diagram showing a returning step S70 in which the peeled first substrate 13 is returned to its original position. For convenience of explanation, Fig. 9 omits a plurality of devices 19 present in the depth direction of the page, as in Fig. 4(B) and Fig. 7. After the returning step S70, the process returns to the laser processing step S10.

[0133] In other words, the controller 82 moves the chuck table 26 to directly below the irradiation head 48 and controls the laser beam irradiation unit 42 to again irradiate the laser beam L so as to destroy the remaining buffer region 15 in contact with one or more devices 19 (reprocessing process).

[0134] Fig. 10 is a diagram showing a re-processing step using the laser beam L. In Fig. 10, like Fig. 4(A), the undestroyed buffer region 15 is shown in white, but the buffer region 15 destroyed in the initial laser processing step S10 is not shown in Fig. 10.

[0135] For example, in the re-processing step, the entire buffer layer 17 is irradiated again with the laser beam L. At this time, in order to reduce damage to the device 19 that has already been successfully transferred, it is preferable to lower the average power of the laser beam L below the average power used in the laser processing step S10.

[0136] Furthermore, instead of irradiating the entire buffer layer 17 with the laser beam L again, the coordinates of the buffer regions 15 that were not properly destroyed in the calculation step S40 may be specified in advance by the controller 82, and in the re-irradiation step, only the buffer regions 15 that were not properly destroyed may be irradiated with the laser beam L. In this case, the average output of the laser beam L may be approximately the same as the average output used in the laser processing step S10.

[0137] The coordinates of the buffer area 15 that was not properly destroyed are specified, for example, by the calculation unit 82a in the calculation step S40. The specified coordinates are stored in the memory 86 and are used in the reprocessing step.

[0138] In this embodiment, when performing laser lift-off, a laser processing step S10 and a calculation step S40 for calculating a transfer rate can be performed in the processing device 2.

[0139] Therefore, the time required to transport the composite substrate 11 can be reduced compared to the case where the composite substrate 11 is transported between the housing of the laser processing device and the housing of the optical inspection device, thereby improving productivity. Furthermore, a re-processing step in the case where the transfer rate is low can also be performed in the processing device 2.

[0140] In the imaging process S30 of the first embodiment, an area corresponding to the entire surface 25a of the second substrate 25 is imaged, but the calculation process S40 may be performed by having the microscope camera unit 54 image only a partial area of ​​the surface 25a.

[0141] In this case, the success or failure of the laser processing result is judged based on the destruction success rate, etc. in a partial region of the surface 25a. In other words, the destruction success rate, etc. in other regions of the surface 25a that are not imaged are estimated based on the destruction success rate, etc. in a partial region of the surface 25a.

[0142] Second Embodiment Next, a second embodiment will be described with reference to Figures 11 and 12. Figure 11 is a flow diagram of laser lift-off in the second embodiment.

[0143] In the second embodiment, after the laser processing step S10 and the peeling step S20, the surface 13a of the first substrate 13 is imaged by a microscope camera unit (another imaging unit) 88 shown in FIG. 12, instead of the microscope camera unit 54 (imaging step S32).

[0144] The microscope camera unit 88 is located to the side of the chuck table 26, and is fixed to the X-axis direction moving plate 18. The direction in which the microscope camera unit 88 captures an image of a subject is opposite to the direction in which the microscope camera unit 54 captures an image.

[0145] Fig. 12 is a diagram showing how the surface 13a of the first substrate 13 is imaged by the microscope camera unit 88 after the peeling step S20 in the second embodiment. For ease of explanation, Fig. 12 omits the second substrate 25 located on the holding surface 26a, the multiple devices 19 present in the depth direction of the page, the clamp unit 26b, the tape 27, the frame 29, and the like.

[0146] In the imaging step S32, devices 19 whose buffer regions 15 were not properly destroyed are imaged, and in the calculation step S40, the calculation unit 82a calculates the destruction failure rate (or destruction success rate) based on the one or more obtained images 54a.

[0147] The subsequent flow is the same as in the first embodiment, and proceeds to a judgment step S50. If the judgment result is pass (YES in S60), the flow ends, but if the judgment result is fail (NO in S60), the flow proceeds to a reprocessing step (i.e., the laser processing step S10) via a return step S70.

[0148] In the second embodiment, after the peeling step S20, the imaging step S32 can be performed in a state where the chuck table 26 is disposed in the vicinity of the peeling unit 56, without moving the chuck table 26 in the X-axis direction to the vicinity of the laser beam irradiation unit 42. Therefore, the productivity can be further improved compared to the first embodiment.

[0149] (Third embodiment) Next, a third embodiment will be described with reference to Fig. 13 and Fig. 14. Fig. 13 is a flow diagram of laser lift-off in the third embodiment. In the third embodiment, after the laser processing step S10 and before the first substrate 13 is peeled off by the peeling unit 56, the microscope camera unit 54 captures an image of the front surface 13a side of the first substrate 13 (imaging step S34).

[0150] 14 is a diagram showing an imaging step S34 in the third embodiment. When buffer region 15 is properly destroyed, the top surface of device 19 in image 54a or the entire image (i.e., the surface closer to first substrate 13) has a different color, contour, etc., compared to the top surface of device 19 in which buffer region 15 is not properly destroyed and remains.

[0151] The calculation unit 82a calculates the destruction success rate based on the image 54a obtained by imaging the front surface 13a side of the first substrate 13 (calculation step S42). After the calculation step S42, the process proceeds to a determination step S50. If the determination result is unsuccessful (NO in S60), the process proceeds to a reprocessing step (i.e., the laser processing step S10).

[0152] On the other hand, if the determination result is pass (YES in S60), controller 82 moves chuck table 26 to directly below peeling unit 56, and peels first substrate 13 from composite substrate 11 (peeling step S62).

[0153] In the third embodiment, the laser processing step S10 is repeated until the judgment result is pass, and only after the judgment result is pass is the first substrate 13 peeled off. Therefore, there is an advantage that the peeling step S20 and the returning step S70 can be omitted when the laser processing step S10 is repeated two or more times.

[0154] (Fourth embodiment) Next, a fourth embodiment will be described with reference to Fig. 15, Fig. 16(A) and Fig. 16(B). Fig. 15 is a flow diagram of laser lift-off in the fourth embodiment. The flow of the fourth embodiment is basically the same as the flow of the first embodiment shown in Fig. 6.

[0155] However, in the fourth embodiment, before the laser processing step S10, the microscope camera unit 54 captures an image of the device layer 21 through the first substrate 13 of the composite substrate 11 held by suction on the holding surface 26a (pre-processing imaging step S4).

[0156] 16(A) is a diagram showing a pre-processing imaging step S4 in the fourth embodiment. Since the image obtained in the pre-processing imaging step S4 is used in a verification operation performed at a later date, it is preferable to image the entire range of the surface 13a of the first substrate 13.

[0157] After the pre-processing imaging process S4, the calculation unit 82a calculates the proportion of devices 19 that are normally formed out of the total number of devices 19 (for convenience, referred to as the normal formation proportion) based on the images obtained by the image linking and image processing functions (pre-processing calculation process S6).

[0158] The buffer layer 17 is very thin, from several hundred Å to about 1 μm, so that the device layer 21 can be imaged through the buffer layer 17. There are only a few abnormal (i.e., defective) devices 19, and in the obtained image, the devices are clearly different in color, shape, etc., from normal devices 19. Therefore, the calculation unit 82a can calculate the normal formation rate based on the obtained image.

[0159] The controller 82 of the fourth embodiment further includes a pre-machining determination unit 82c (see FIG. 16B). The pre-machining determination unit 82c can be realized by causing the processor 84 to execute a third program stored in the auxiliary storage device.

[0160] 16B is a block diagram for explaining the function of the controller 82 in the fourth embodiment. The pre-processing determination unit 82c determines whether or not the multiple devices 19 are normally formed (pre-processing determination step S8).

[0161] The memory 86 pre-stores a threshold value (e.g., 99.5%) of the ratio of the number of devices 19 that are normally formed to the total number of devices 19, and the pre-processing judgment unit 82c reads out this threshold value from the memory 86 and compares it with the normal formation ratio calculated by the calculation unit 82a.

[0162] If the normal formation rate is equal to or higher than the threshold value in the pre-processing judgment step S8, the pre-processing judgment unit 82c judges that the devices 19 are normally formed on the composite substrate 11. The judgment result is stored in the memory 86 together with the normal formation rate.

[0163] In the pre-processing calculation step S6, the calculation unit 82a may calculate the ratio of the number of devices 19 that are not normally formed (for convenience, referred to as the abnormal formation ratio) to the total number of devices 19. The complementary event of normal formation is abnormal formation (i.e., the sum of the normal formation ratio and the abnormal formation ratio is 1).

[0164] When the calculation unit 82a calculates the abnormality formation rate, a threshold value (e.g., 0.5%) of the ratio of the number of devices 19 that are not formed normally to the total number of devices 19 is pre-stored in the memory 86, and in the pre-processing judgment step S8, the pre-processing judgment unit 82c reads out this threshold value from the memory 86 and compares it with the abnormality formation rate calculated by the calculation unit 82a.

[0165] If the rate of abnormality formation is less than the threshold value in the pre-processing judgment step S8, the pre-processing judgment unit 82c judges that the device 19 is normally formed. The judgment result is stored in the memory 86 together with the rate of abnormality formation.

[0166] In the fourth embodiment, the calculation unit 82a and the pre-processing judgment unit 82c can confirm whether the device 19 is formed normally before the laser processing step S10. Therefore, if a defect is discovered in a product or semi-finished product equipped with the device 19 at a later date, it has the advantage that it can be clearly identified whether or not the defect is caused by the laser processing step S10.

[0167] (First Modification) Next, a first modification will be described with reference to Fig. 17(A), Fig. 17(B) and Fig. 18. In the first modification, before the laser processing step S10, an operator inputs information through the touch panel 74 to divide the surface 13a of the first substrate 13 into a plurality of processing regions, and sets different processing conditions for each of the processing regions.

[0168] The different processing conditions mean that one or more elements of the wavelength, repetition frequency, average output, and moving speed and diameter of the focal point of the laser beam L are different in the laser processing step S10.

[0169] 17A, the controller 82 of the first modified example has a machining condition changing unit 82d. The machining condition changing unit 82d changes the machining conditions according to the machining area in accordance with the set machining conditions.

[0170] 17A is a block diagram for explaining the function of the controller 82 in the first modified example. The processing condition change unit 82d can be realized by the processor 84 executing a fourth program stored in the auxiliary storage device.

[0171] FIG. 17B shows four processing regions 13a 11 ,13a 12 ,13a 21 ,13a 22 17(B) is a plan view of composite substrate 11 for illustrating the above-mentioned structure. For ease of explanation, rear surface 13b of first substrate 13 is omitted in FIG.

[0172] 17(B), the surface 13a of the first substrate 13 is divided into four rectangular regions, but the number of regions is not limited to four, and the shape of the processing region is not limited to a rectangle. In the first modified example, the processing device 2 also performs each process on the composite substrate 11 according to the flow shown in FIG.

[0173] In the following, the explanation will be given according to the flow shown in FIG. 6, but the first variant example may be combined with the flow shown in FIG. 11 (second embodiment), FIG. 13 (third embodiment), or FIG. 15 (fourth embodiment).

[0174] In the laser processing step S10, the laser beam irradiation unit 42 irradiates the buffer layer 17 with a laser beam L under processing conditions set for each processing region.

[0175] Thereafter, after the peeling step S20 and the imaging step S30, in the calculation step S40, the calculation unit 82a calculates the destruction success rate (or destruction failure rate) for each processed region based on the image obtained in the imaging step S30.

[0176] Next, in the determination step S50, the controller 82 causes the touch panel 74 to display the different processing conditions, processing times, and the destruction success rate (or destruction failure rate) for each processing region.

[0177] FIG. 18 is a diagram showing an example of a screen display of the touch panel 74 showing the destruction success rate and the processing time for each processing condition. 11 corresponds to the processing conditions applied to

[0178] Similarly, recipe #2 is processed in area 13a 12 Recipe #3 corresponds to the processing conditions applied to processing area 13a 21 Recipe #4 corresponds to the processing conditions applied to processing area 13a 22 corresponds to the processing conditions applied to

[0179] The destruction success rate and the processing time are not necessarily compatible. Therefore, if processing conditions with a high destruction success rate are selected, the processing time will be long, and if processing conditions with a short processing time are selected, the destruction success rate will be low. Therefore, the lower limit threshold of the destruction success rate and the upper limit threshold of the processing time are preset in the controller 82 by the operator.

[0180] In this case, the controller 82 selects the processing conditions (i.e., recipe) in which the destruction success rate is equal to or greater than the lower threshold and the processing time is equal to or less than the upper threshold after the calculation step S40, and then displays the recommended processing conditions on the touch panel 74. In the first modified example, by setting different processing conditions for each processing area, the optimum processing conditions can be automatically selected.

[0181] (Second Modification) Next, the second modification will be described with reference to Fig. 19(A) and Fig. 19(B). The second modification will also be described according to the flow shown in Fig. 6, but the second modification may be combined with the flow shown in Fig. 11 (second embodiment), Fig. 13 (third embodiment) or Fig. 15 (fourth embodiment).

[0182] In the second variant, the laser processing step S10 is performed under specified processing conditions, and then the controller 82 associates the destruction success rate (or destruction failure rate) with the specified processing conditions based on the image obtained in the imaging step S30 and stores them in the memory 86.

[0183] Then, at the timing after the judgment step S50, when the destruction success rate obtained by performing the laser processing under the predetermined processing conditions falls below the first threshold value, the notification device 80 (see Fig. 2 and Fig. 5) notifies the operator that the destruction success rate falls below the predetermined threshold value. Fig. 19(A) is a diagram showing an example of a screen display when the destruction success rate falls below the first threshold value A1.

[0184] Alternatively, when the failure rate of destruction obtained by performing laser processing under a predetermined processing condition exceeds the second threshold, the notification device 80 may notify the operator that the failure rate of destruction has exceeded the second threshold. Fig. 19(B) is a diagram showing an example of a screen display when the failure rate of destruction has exceeded the second threshold A2.

[0185] In the second variant, not only can the transfer rate of each of a large number of composite substrates 11 be checked during the production process, but when the processing device 2 is operated on a trial basis, it can also be quickly checked whether the processing device 2 is operating normally.

[0186] In addition, the structures, methods, etc. according to the above-mentioned embodiments can be appropriately modified without departing from the scope of the present invention. The composite substrate 11 is not limited to a rectangular shape, and may have a disk shape. In this case, the first substrate 13 and the second substrate 25 are disks of approximately the same diameter. [Explanation of symbols]

[0187] 2: Processing device, 4: Base, 4a: Housing, 6: Moving mechanism 8: Y-axis guide rail, 10: Y-axis direction moving plate, 12: screw shaft, 14: driving source 11: Composite board 13: first substrate, 13a: front surface (first surface), 13b: back surface 13a 11 ,13a 12 ,13a 21 ,13a 22 :Processing area 15: buffer region, 15a: substrate fixing surface, 15b: device fixing surface 16: X-axis guide rail, 18: X-axis direction moving plate, 20: screw shaft, 22: driving source 17: Buffer layer 19: device, 19a: growth start surface, 19b: fixed surface, 21: device layer 23: Bonding material, 25: Second substrate, 25a: Front surface (second surface), 25b: Back surface (third surface) 24: Table base 26: chuck table (holding table), 26a: holding surface, 26b: clamp unit 27: tape, 29: frame, 31: composite board unit 30: First support structure, 32: Z-axis direction movement mechanism 34: Z-axis guide rail, 36: Z-axis direction moving plate, 38: driving source, 40: support 42: laser beam irradiation unit, 44: housing, 46: laser oscillator 48: Irradiation head, 50: Galvano scanner 50a: first mirror, 50b: second mirror, 52: telecentric fθ lens 54: microscope camera unit (imaging unit), 54a: image 56: peeling unit, 58a: cylindrical part, 58b: head part, 58c: suction pad 60: Second support structure, 62: Z-axis direction movement mechanism 64: Z-axis guide rail, 66: Z-axis direction moving plate, 68: driving source, 70: support 72: Housing 74: touch panel, 76: speaker, 78: rotating light, 80: alarm device 82: controller, 82a: calculation unit, 82b: post-processing determination unit, 82c: pre-processing determination unit 82d: Processing condition change section 84: Processor, 86: Memory 88: Microscope camera unit (other imaging unit) A1: First threshold, A2: Second threshold L: Laser beam S4: Pre-processing imaging process, S6: Pre-processing calculation process, S8: Pre-processing judgment process S10: Laser processing process, S20: Peeling process, S30, S32, S34: Imaging process S40, S42: Calculation steps, S50: Determination step, S62: Peeling step, S70: Returning step

Claims

1. A processing apparatus for separating a plurality of devices from a composite substrate including a first substrate, a second substrate, and a plurality of devices sandwiched between the first substrate and the second substrate by utilizing a pulsed laser beam, the processing apparatus comprising: a device layer including the plurality of devices is fixed to the first surface side of the first substrate via a buffer layer, and a fixed surface of the device layer located on the opposite side to the buffer layer is fixed to the second surface of the second substrate, the second substrate of the composite substrate having such a fixed surface, the device layer being located on the opposite side to the buffer layer, fixed to the second surface of the second substrate; and a laser beam irradiation unit having a laser oscillator, for irradiating the composite substrate held by the holding table with the laser beam in a direction proceeding from the first substrate to the second substrate, the laser beam having a wavelength that is transmitted through the first substrate but absorbed by the buffer layer, thereby destroying buffer regions in the buffer layer corresponding to each device; a peeling unit that peels off the first substrate from the composite substrate in which at least a portion of the buffer layer is destroyed; an imaging unit for imaging the device layer or the buffer layer; a controller having a processor and a memory, and controlling the holding table, the laser beam irradiation unit, the peeling unit and the imaging unit; The controller a calculation unit that calculates a destruction success ratio, which is the number of buffer regions that have been destroyed to an extent that the device and the first substrate are separated out of the total number of buffer regions corresponding to the plurality of devices, or a destruction failure ratio, which is the number of buffer regions that have not been destroyed to an extent that the device and the first substrate are separated out of the total number, based on an image obtained by imaging the device layer or the buffer layer after laser processing by the laser beam irradiation unit with the imaging unit; A processing device comprising:

2. 2. The processing apparatus according to claim 1, wherein the controller further comprises a post-processing judgment unit that judges whether a result of the laser processing is acceptable or not based on the destruction success rate or the destruction failure rate calculated by the calculation unit.

3. The processing apparatus according to claim 2, characterized in that if the post-processing judgment section judges that the processing is unsuccessful, the controller controls the laser beam irradiation unit to irradiate the laser beam again so as to destroy the remaining buffer area in contact with one or more devices.

4. the laser beam irradiation unit irradiates the buffer region corresponding to each device with the laser beam, and the peeling unit peels off the first substrate, and then the calculation unit calculates the destruction success rate or the destruction failure rate based on an image obtained by imaging the second surface side of the second substrate with the imaging unit; The processing apparatus according to claim 3, characterized in that if the judgment result in the post-processing judgment unit based on the destruction success rate or the destruction failure rate is failure, the controller returns the first substrate to its original position so that the first substrate overlaps the second substrate, and then controls the laser beam irradiation unit to irradiate the laser beam again so as to destroy the remaining buffer region in a manner that contacts the one or more devices.

5. the laser beam irradiation unit irradiates the buffer region corresponding to each device with the laser beam, and the peeling unit peels off the first substrate, and then the calculation unit calculates the destruction success rate or the destruction failure rate based on an image obtained by imaging the first surface side of the first substrate with an imaging unit different from the imaging unit; The processing apparatus according to claim 3, characterized in that if the judgment result in the post-processing judgment unit based on the destruction success rate or the destruction failure rate is failure, the controller returns the first substrate to its original position so that the first substrate overlaps the second substrate, and then controls the laser beam irradiation unit to irradiate the laser beam again so as to destroy the remaining buffer region in a manner that contacts the one or more devices.

6. After the laser beam irradiation unit irradiates the buffer region corresponding to each device with the laser beam and before the peeling unit peels off the first substrate, the calculation unit calculates the destruction success rate or the destruction failure rate based on an image obtained by imaging the first surface side of the first substrate with the imaging unit; The processing apparatus according to claim 3, characterized in that if the judgment result in the post-processing judgment section based on the destruction success rate or the destruction failure rate is failure, the controller controls the laser beam irradiation unit to irradiate the laser beam again through the first substrate so as to destroy the remaining buffer region in a manner contacting the one or more devices.

7. The controller The processing apparatus according to any one of claims 1 to 6, further comprising a pre-processing judgment unit that judges whether or not the plurality of devices are formed normally based on an image obtained by imaging the device layer through the first substrate of the composite substrate held on the holding table, before the laser beam irradiation unit irradiates the composite substrate with the laser beam.

8. Further comprising a display device, The controller further includes a processing condition change unit that executes laser processing under processing conditions different from each other that are set by an operator for each of a plurality of processing regions that constitute the first surface of the first substrate, After the buffer layer is irradiated with the laser beam under processing conditions designated by the processing condition changing unit for each of the plurality of processing regions, the calculation unit calculates the destruction success rate or the destruction failure rate for each of the processing regions based on an image obtained by imaging the device layer or the buffer layer with the imaging unit; The processing device according to any one of claims 1 to 6, characterized in that the controller causes the display device to display the different machining conditions and the destruction success rate or the destruction failure rate for each machining area calculated by the calculation unit.

9. After the laser beam irradiation unit irradiates the buffer region corresponding to each device with the laser beam under predetermined processing conditions, the controller associates the destruction success rate or the destruction failure rate calculated by the calculation unit based on an image obtained by imaging the device layer or the buffer layer with the imaging unit, with the predetermined processing conditions, and stores them in the memory; The processing device according to any one of claims 1 to 6, further comprising an alarm device for notifying an operator that the rate of successful destruction obtained by performing laser processing under the specified processing conditions has fallen below a first threshold value or that the rate of failed destruction has exceeded a second threshold value when the rate of successful destruction obtained by performing laser processing under the specified processing conditions has fallen below a first threshold value or that the rate of failed destruction has exceeded a second threshold value.

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