TW202105466A - Method for transferring optical component can remove the buffer layer remanent on the optical component layer without pickling - Google Patents

Abstract

A method for transferring an optical component is provided. When the optical component layer is transferred, the buffer layer remanent on the optical component layer can be removed without pickling. The method for transferring an optical component includes a transfer substrate bonding step ST11, a buffer layer destruction step ST12, an optical component layer transferring step ST13, and a buffer layer removing step ST14. In the optical component layer transferring step ST13, which is after the buffer layer destruction step ST12, the epitaxy substrate is peeled from the optical component layer and the optical component layer is transferred to the transfer substrate. In the buffer layer removing step ST14, which is after the optical component layer transferring step ST13, a pulsed laser beam with a wavelength having the absorptivity is irradiated on the buffer layer remanent on the optical component layer to remove the remanent buffer layer.

Description

Relocation method of optical element

The present invention relates to a method for transferring optical components.

Optical elements such as LEDs (Light Emitting Diodes) are formed by, for example, epitaxial growth of an n-type semiconductor layer and a p-type semiconductor layer constituting a pn junction on the surface of a sapphire substrate. A peeling technique is known, which is a so-called laser peeling technique in which the optical element layer formed as described above is peeled from the sapphire substrate (see Patent Documents 1 and 2). The optical element layer is formed on a sapphire substrate with a buffer layer interposed therebetween. In the laser lift-off method, the buffer layer is irradiated with a laser beam to separate the sapphire substrate and the optical element layer, and the optical element layer is moved to the substrate. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] JP 2004-072052 A [Patent Document 2] JP 2016-021464 A

[The problem to be solved by the invention] In the past, by applying hydrochloric acid (HCL) pickling to the transferred optical element layer, the residue of the buffer layer damaged by the irradiation of the laser beam was removed, and it was directly attached to the optical element layer without being damaged. The buffer layer and so on. However, there are the following problems: the cost is greatly increased due to the waste liquid treatment, the waste liquid treatment is a dangerous operation, and a cleaning step for removing hydrochloric acid is further required after pickling, which increases the time required.

In view of the above-mentioned problems, the purpose of the present invention is to provide a method for transferring an optical element. When the optical element layer is transferred, the buffer layer remaining on the optical element layer is removed without performing pickling.

[Technical means to solve the problem] In order to solve the above-mentioned problems and achieve the objective, the optical element transfer method of the present invention transfers the optical element of the optical element wafer in which the optical element layer is laminated on the front surface of the epitaxial substrate via the buffer layer to the transfer substrate, which is characterized by The method includes: a transfer substrate bonding step of bonding the transfer substrate through the bonding layer on the front surface of the optical element layer of the optical element wafer to form a composite substrate; a buffer layer destruction step, after the transfer substrate bonding step, from forming the composite substrate The back side of the epitaxial substrate of the optical element wafer is irradiated with a pulsed laser beam of a wavelength penetrating the epitaxial substrate and absorbing to the buffer layer to destroy the buffer layer; and the optical element layer transfer step, in the buffer layer After the layer destruction step, peel the epitaxial substrate from the optical element layer and transfer the optical element layer to the transfer substrate; after the optical element layer transfer step, irradiate a wavelength that absorbs the buffer layer remaining on the optical element layer This pulsed laser beam is subjected to a buffer layer removal step for removing the remaining buffer layer.

It may also include a micro-light-emitting diode forming step, which divides the light element layer into wafer sizes and forms a micro-light-emitting diode before the transfer substrate bonding step.

It may also include a mounting step, which picks up the optical element layer from the transfer substrate and mounts it on the mounting substrate after the buffer layer removal step.

[Efficacy of invention] In the present invention, when the optical element layer is transferred, the buffer layer remaining on the optical element layer can be removed without performing pickling.

With reference to the drawings, the mode (embodiment) for implementing the present invention will be described in detail. The present invention is not limited by the content described in the following embodiments. In addition, the constituent elements described below include substantially the same technical content that can be easily thought of by those having ordinary knowledge in the technical field to which the present invention belongs. Furthermore, the configurations described below can be appropriately combined. In addition, various omissions, substitutions, or changes in the configuration can be made without departing from the scope of the present invention.

[Implementation] The relocation method of the embodiment of the present invention will be described based on the drawings. First, the structure of the optical element wafer 1 to be transferred including the transfer method of the optical element 7 of the embodiment will be described. FIG. 1 is a perspective view of an optical element wafer 1 that includes a transfer target of an optical element 7 transfer method according to the embodiment. FIG. 2 is a cross-sectional view of the optical element wafer 1 of FIG. 1. In addition, FIGS. 1 and 2 illustrate the optical element layer 5 and the like of the optical element wafer 1 in a larger size than the actual size for the description of the present embodiment, and the following drawings are also the same. As shown in FIG. 2, the optical element wafer 1 includes an epitaxial substrate 2 and an optical element layer 5 laminated on the front surface 3 of the epitaxial substrate 2 with a buffer layer 4 interposed therebetween.

In this embodiment, the epitaxial substrate 2 is a sapphire substrate having a circular plate shape with a diameter of about 6 inches (about 150 mm) and a thickness of about 1.2 mm to 1.5 mm. In this embodiment, the optical element layer 5, as shown in FIG. 2, is formed on the front surface 3 of the epitaxial substrate 2 by the epitaxial growth method into an n-type gallium nitride semiconductor layer 5-1 with a total thickness of about 6 µm and The p-type gallium nitride semiconductor layer 5-2. The optical element layer 5 is used as an LED, for example. In this embodiment, the buffer layer 4 is formed between the front surface 3 of the epitaxial substrate 2 and the p-type gallium nitride semiconductor layer 5-2 of the optical element layer 5 when the optical element layer 5 is laminated on the epitaxial substrate 2. The thickness of the gallium nitride (GaN) layer is about 1µm.

In this embodiment, as shown in FIG. 1, the optical element layer 5 is divided into a wafer size in a plurality of regions divided by a plurality of dicing lanes 6 intersecting in a lattice shape, and the optical element 7 is laminated to form the optical element 7. The distance between the optical element layers 5, that is, the distance between the optical elements 7 is the same as the width of the scribe lane 6. In this embodiment, the distance between the optical element layers 5 is about 5 μm. The size of the optical element layer 5, that is, the size of the optical element 7, is the same as the distance between the dicing lanes 6 and each other. In this embodiment, the size of the optical element layer 5 is approximately 10 μm to 20 μm. In the optical element layer 5, in this embodiment, about 2 million optical elements 7 used as LEDs are formed on an epitaxial substrate 2 having a diameter of 6 inches. Furthermore, the epitaxial substrate 2 may also be a CMOS (Complementary Metal Oxide Semiconductor) wafer. The wafer size of the CMOS element is, for example, about 8 mm to 11 mm, and a plurality of optical element layers 5 are formed on this CMOS element.

Next, the transfer method of the optical element 7 of the embodiment will be described. FIG. 3 is a flowchart showing the method of transferring the optical element 7 according to the embodiment. The method for transferring the optical element 7 is as shown in FIG. 3 and includes: a substrate bonding step ST11, a buffer layer destruction step ST12, an optical element layer transfer step ST13, and a buffer layer removal step ST14.

4 is a cross-sectional view showing a state of the transfer substrate bonding step ST11 of FIG. 3. FIG. 5 is a cross-sectional view showing a state after FIG. 4 in the transfer substrate bonding step ST11 of FIG. 3. The transfer substrate bonding step ST11 is a step of bonding the transfer substrate 11 to the front surface of the optical element layer 5 of the optical element wafer 1 through the bonding layer 12 to form the composite substrate 10 as shown in FIGS. 4 and 5.

In the transfer substrate joining step ST11, specifically, as shown in FIG. 4, first, a transfer substrate 11 having the same size as the epitaxial substrate 2 is prepared. An adhesive is applied to one surface of the transfer substrate 11 to form a bonding layer 12.

In addition, in the present embodiment, the transfer substrate 11 is a glass substrate having a thickness of about 2.0 mm which is the same as that of the epitaxial substrate 2 and is used as a suitable substrate, but the present invention is not limited to this. The transfer substrate 11 may be bonded to a predetermined adhesive, and a substrate made of various other materials such as a metal substrate may also be used.

In addition, the adhesive is preferably composed of an organic compound. For example, a paste for adhering an adhesive film is used. The adhesive has the following properties: it is softened by heating and the viscosity is reduced, and further by heating or irradiating ultraviolet rays, it will cause a chemical reaction such as a curing reaction to harden and thereby reduce the viscosity.

In the transfer substrate bonding step ST11, next, the optical element layer 5 laminated on the epitaxial substrate 2 and the bonding layer 12 formed by the adhesive applied to the transfer substrate 11 are opposed, approached, and brought into contact with each other. In the transfer substrate bonding step ST11, the substrate 11 is transferred from the side opposite to the front surface 3 of the epitaxial substrate 2, that is, the back surface 8 side, or from the transfer substrate 11 and the bonding layer 12 side coated with the adhesive The opposite side faces the epitaxial substrate 2 and is pressed. Thereby, in the transfer substrate bonding step ST11, as shown in FIG. 5, the bonding layer 12 is deformed along the optical element layer 5 so that a part of the optical element layer 5 is buried in the bonding layer 12. In this way, in the transfer substrate bonding step ST11, the transfer substrate 11 is bonded to the front surface of the optical element layer 5 of the optical element wafer 1 through the bonding layer 12 to form the composite substrate 10.

In the transfer substrate bonding step ST11, in the present embodiment, a bonding layer formed by an adhesive is provided in such a way that there is a gap 15 between the optical element layer 5 and the optical element layer 5 that are divided into chip sizes of the optical element wafer 1. 12 Bond the optical element layer 5 side of the optical element wafer 1 and the transfer substrate 11. Here, in the transfer substrate bonding step ST11, it is preferable to simultaneously control the pressing force and the temperature at the time of bonding so that the gap 15 between the optical element layers 5 is not buried in the adhesive. In addition, in the transfer substrate bonding step ST11, although bonding by an adhesive is adopted in this embodiment, the present invention is not limited to this, and other bonding methods may be adopted.

FIG. 6 is a cross-sectional view showing an example of the buffer layer destruction step ST12 of FIG. 3. The buffer layer destruction step ST12 is shown in FIG. 6, after the transfer substrate bonding step ST11, irradiation from the back 8 side of the epitaxial substrate 2 of the optical element wafer 1 constituting the composite substrate 10 is transparent and transparent to the epitaxial substrate 2 The step of destroying the buffer layer 4 by a pulsed laser beam 34 of a wavelength having absorption to the buffer layer 4.

In the buffer layer destruction step ST12, specifically, as shown in FIG. 6, first, the surface on the transfer substrate 11 side of the composite substrate 10 of the transfer substrate 11 and the optical element wafer 1 bonded in the transfer substrate bonding step ST11 is bonded. It is sucked and held on the holding surface 21 of the chuck table 20 connected to a vacuum source (not shown).

In the buffer layer destruction step ST12, next, from the back 8 side of the epitaxial substrate 2 of the composite substrate 10 of the optical element wafer 1 held by the chuck table 20 and the transfer substrate 11, the laser beam irradiation unit 30 removes The pulse laser beam 34 irradiates the buffer layer 4. The pulsed laser beam 34 is a pulsed laser beam with a wavelength that is penetrative to the epitaxial substrate 2 and is absorbing to the buffer layer 4. Thereby, in the buffer layer destruction step ST12, the buffer layer 4 is destroyed. In the buffer layer destruction step ST12, in the present embodiment, the entire surface of the epitaxial substrate 2 is irradiated with the pulsed laser beam 34, but the present invention is not limited to this. In the buffer layer destruction step ST12, the pulse laser beam 34 may be irradiated only on the position of the epitaxial substrate 2 where the buffer layer 4 is formed.

Here, as shown in FIG. 6, the laser beam irradiation unit 30 oscillates the above-mentioned pulsed laser beam 34 of the predetermined wavelength by the laser beam oscillation means 31. The laser beam irradiation unit 30 changes the pulse laser beam 34 from the laser beam oscillation means 31 to face the back 8 of the epitaxial substrate 2 of the composite substrate 10 held by the chuck table 20 by the optical mirror 32 Orthogonal direction. The laser beam irradiation unit 30 condenses the pulsed laser beam 34 from the optical mirror 32 by the condenser lens 33. The laser beam irradiation unit 30 adjusts the irradiation conditions such as output or defocus amount of the pulsed laser beam 34 in the buffer layer destruction step ST12.

In the buffer layer destruction step ST12, for example, ultraviolet laser light having a repetition frequency of approximately 50 kHz to 200 kHz and an average output of approximately 0.1 W to 2.0 W is used as the pulsed laser beam 34. In the buffer layer destruction step ST12, for example, the spot diameter is set to about 10µm to 50µm, the defocus is adjusted to about 1.0mm to 2.0mm, the overlap ratio is adjusted to about 20% to 60%, and buffering is performed. Destruction of layer 4.

FIG. 7 is a cross-sectional view showing an example of the optical element layer transfer step ST13 in FIG. 3. The optical element layer transfer step ST13 is a step of peeling the epitaxial substrate 2 from the optical element layer 5 after the buffer layer destruction step ST12 and transferring the optical element layer 5 laminated on the epitaxial substrate 2 to the transfer substrate 11.

In the optical element layer transfer step ST13, specifically, from the back 8 side of the epitaxial substrate 2 of the composite substrate 10 where the buffer layer 4 was destroyed in the buffer layer destruction step ST12, an ultrasonic vibration (not shown) is provided. The horn of the method applies ultrasonic vibration. Thereby, in the optical element layer transfer step ST13, using the damaged buffer layer 4 as a starting point, the epitaxial substrate 2 is peeled from the optical element layer 5 and the optical element layer 5 is transferred to the transfer substrate 11.

In the optical element layer transfer step ST13, as shown in FIG. 7, by pulling the epitaxial substrate 2 away from the optical element layer 5, the transfer substrate 11, and the bonding layer 12, the optical element 5 layer transferred to the transfer substrate 11 is formed ( The optical element 7) The optical element layer transfer substrate 13 in a state where the bonding layer 12 protrudes.

FIG. 8 is a cross-sectional view showing an example of step ST14 of removing the buffer layer. The buffer layer removal step ST14 is shown in FIG. 8, after the optical element layer transfer step ST13, a pulsed laser beam 34 having a wavelength that is absorptive to the buffer layer 4 remaining on the optical element layer 5 is irradiated to remove the remaining buffer layer 4 of the steps.

In the buffer layer removal step ST14, specifically, as shown in FIG. 8, the optical element layer transfer substrate 13 from the optical element layer 5 side of the epitaxial substrate 2 peeled off in the optical element layer transfer step ST13 is performed by laser The beam irradiation unit 30 irradiates the pulsed laser beam 34 to the remaining pulse layer 4. At this time, the surface of the optical element layer transfer substrate 13 on the transfer substrate 11 side is sucked and held on the holding surface 21 of the chuck table 20 connected to a vacuum source (not shown). It is preferable that the chuck table 20 continues to be sucked and held from the buffer layer destruction step ST12. The pulsed laser beam 34 is a pulsed laser beam with a wavelength that is absorptive to the buffer layer 4. Thereby, in the buffer layer removal step ST14, the buffer layer 4 is removed. Here, the laser irradiation unit 30 is preferably the same device as the laser beam irradiation unit 30 used in the buffer layer destruction step ST12.

In the buffer layer removal step ST14, for example, ultraviolet laser light having a repetition frequency of approximately 50 kHz to 200 kHz and an average output of approximately 0.1 W to 2.0 W is used as the pulsed laser beam 34. In the buffer layer removal step ST14, for example, the spot diameter is set to about 10 µm to 50 µm, the defocus is adjusted to about 1.0 mm to 2.0 mm, and the overlap ratio is adjusted to about 20% to 60%, and the buffer layer is executed. 4's removal process. The repetition frequency, average output, spot diameter, defocus, and overlap ratio of the pulsed laser beam 34 in the buffer layer removal step ST14 may also be different values from the parameters of the buffer layer destruction step ST12. For example, the average output may be 0.68W in the buffer layer destruction step ST12, and 0.64W in the buffer layer removal step ST14. For example, the defocus may be 1.2 mm in the buffer layer destruction step ST12 and 2.0 mm in the buffer layer removal step ST14.

The transfer method of the optical element 7 of the optical element wafer 1 of the embodiment includes: a transfer substrate bonding step ST11, a buffer layer destruction step ST12, an optical element layer transfer step ST13, and a buffer layer removal step ST14. In the transfer substrate bonding step ST11, the transfer substrate 11 is bonded to the front surface of the optical element layer 5 of the optical element wafer 1 through the bonding layer 12 to form the composite substrate 10. In the buffer layer destruction step ST12, from the back 8 side of the epitaxial substrate 2 of the optical element wafer 1 constituting the composite substrate 10, a pulse having a wavelength that is transparent to the epitaxial substrate 2 and is absorbing to the buffer layer 4 is irradiated The laser beam 34 destroys the buffer layer 4. In the optical element layer transfer step ST13, after the buffer layer destruction step ST12, the epitaxial substrate 2 is peeled from the optical element layer 5 and the optical element layer 5 is transferred to the transfer substrate 11. In the buffer layer removal step ST14, after the optical element layer transfer step ST13, a pulsed laser beam 34 having a wavelength that absorbs the buffer layer 4 remaining on the optical element layer 5 is irradiated to remove the remaining buffer layer 4.

Thereby, the buffer layer 4 can be cleaned using the same means as the laser beam irradiation means (laser beam irradiation unit 30) used in the buffer layer destruction step ST12 for destroying the buffer layer 4. Therefore, the steps required for the transfer of the optical element 7 can be shortened. In addition, since there is no need to prepare chemical liquids, pickling equipment, and waste liquid treatment equipment for pickling, cost increases can be suppressed. In addition, it can also reduce the environmental load caused by pickling and waste liquid treatment.

[First Modification Example] The transfer method of the first modification of the embodiment of the present invention will be described. FIG. 9 is a flowchart showing a method of transferring the optical element 7 according to the first modification. The method for transferring the optical element 7 is as shown in FIG. 9, including: a micro light emitting diode formation step ST10, a transfer substrate bonding step ST11, a buffer layer destruction step ST12, an optical element layer transfer step ST13, and a buffer layer removal step ST14. The transfer method of the modified example is the same as the embodiment except that it further includes the micro light emitting diode forming step ST10.

10 is a cross-sectional view of the optical element wafer 1 before the micro light emitting diode forming step ST10 of FIG. 9 is implemented. FIG. 11 is a cross-sectional view showing an example of the step ST10 of forming the micro light emitting diode of FIG. 9. In addition, the parts in FIG. 10 and FIG. 11 that are the same as those in the embodiment are denoted by the same reference numerals, and the description thereof is omitted. The micro-light-emitting diode formation step ST10 is a step of dividing the light element layer 5 into wafer sizes and forming micro-light-emitting diodes before the transfer substrate bonding step ST11.

The light element 7 is a micro light emitting diode in the first modification. The optical element layer 5 is in the state before the formation of the micro light emitting diode in the first modification. In the first modification example, as shown in FIG. 10, an optical element wafer 1 includes an epitaxial substrate 2 and an optical element layer 5 laminated on the front surface 3 side of the epitaxial substrate 2 with a buffer layer 4 interposed therebetween.

In the micro light-emitting diode formation step ST10, specifically, first, the planned dividing line for dividing the optical element layer 5 is set. The planned dividing line is a line that coincides with the dicing lane 6. As shown in FIG. 11, the laser beam irradiation unit 30 irradiates the optical element layer 5 with a pulsed laser beam 34 along a predetermined dividing line. The pulsed laser beam 34 is a pulsed laser beam with a wavelength that is penetrative to the epitaxial substrate 2 and is absorbing to the buffer layer 4. In the micro-light-emitting diode forming step ST10, the pulsed laser beam 34 is irradiated along the predetermined dividing line so as to form the predetermined width and depth of the scribe lane 6. The depth of the cutting lane 6 is equal to the thickness of the optical element layer 5 or greater than the thickness of the optical element layer 5. Thereby, in the micro-light-emitting diode forming step ST10, the dicing lane 6 is formed in the optical element layer 5, and the light element 7 as a micro-emitting diode is formed in the area divided by the dicing lane 6.

In the micro-light-emitting diode forming step ST10, in the first modification, the dicing lane 6 is formed by laser processing, but the present invention is not limited to this, and other processing methods may be adopted. In the micro light emitting diode forming step ST10, for example, the dicing lane 6 may also be formed by etching using a cutting device or the like.

The method of transferring the optical element 7 of the optical element wafer 1 of the first modification includes the step of dividing the optical element layer 5 (optical element 7) into wafer sizes and forming micro light emitting diodes before the substrate bonding step ST11. The micro light emitting diode formation step ST10. When the light element 7 is a micro light-emitting diode, if the buffer layer 4 is removed by pickling, the chemical solution flows to the side of the light element 7, which may cause not only the buffer layer 4 but also the light element layer 5 to be removed. doubt. In the buffer layer removal step ST14, the remaining buffer layer 4 is removed by irradiating a pulsed laser beam 34 having an absorptive wavelength, so that only the buffer layer 4 can be processed. Therefore, it is possible to prevent the optical element layer 5 and the bonding layer 12 from being accidentally removed.

[Second Modification Example] The transfer method of the second modification of the embodiment of the present invention will be described. FIG. 12 is a flowchart showing the method of transferring the optical element 7 according to the second modification. The transfer method of the optical element 7 is as shown in FIG. 12, including: a transfer substrate bonding step ST11, a buffer layer destruction step ST12, an optical element layer transfer step ST13, a buffer layer removal step ST14, and a mounting step ST15. The transfer method of the modified example is the same as the embodiment except that it further includes the mounting step ST15.

Fig. 13 is a cross-sectional view showing a state of the mounting step ST15 of Fig. 12. Fig. 14 is a cross-sectional view showing a state after Fig. 13 in the mounting step ST15 of Fig. 12. In addition, the parts in FIGS. 13 and 14 that are the same as those in the embodiment are denoted by the same reference numerals, and the description thereof will be omitted. The mounting step ST15 is shown in FIGS. 13 and 14, and is a step of picking up the optical element layer 5 from the transfer substrate 11 and mounting on the mounting substrate 100 after the buffer layer removal step ST14.

In the mounting step ST15, specifically, first, it is preferable to perform an adhesiveness reduction process which reduces the adhesiveness of the adhesive of the bonding layer 12 supporting the optical element layer 5 (optical element 7). The adhesion reduction treatment is, for example, a treatment for reducing the viscosity of the adhesive by heating the bonding layer 12, or by irradiating the bonding layer 12 with ultraviolet rays or heating to cause a curing reaction such as a polymerization reaction, thereby Treatment to reduce the adhesiveness of the adhesive. The adhesion reduction process enables the pickup unit 50 to pick up the optical element layer 5 (optical element 7) with less force, which improves the picking accuracy and reduces and suppresses the adhesive remaining on the optical element layer 5 (optical element 7).

In the mounting step ST15, next, as shown in FIG. 13, the optical element layer 5 (optical element 7) is gripped or held by suction in the pickup portion 51 of the pickup unit 50. At this time, the surface of the optical element layer transfer substrate 13 on the transfer substrate 11 side is sucked and held on the holding surface 21 of the chuck table 20 connected to a vacuum source (not shown). The chuck table 20 may continue to be sucked and held from the buffer layer destruction step ST12. Thereby, the transfer substrate 11 and the bonding layer 12 remain on the chuck table 20, and only the optical element layer 5 is picked up by the pickup unit 51 of the pickup unit 50. The pickup unit 51 is arranged side by side at a position facing the optical element layer 5 (optical element 7). Each pick-up part 51 picks up each optical element layer 5 (optical element 7) in an opposing position. In the mounting step ST15, afterwards, as shown in FIG. 14, the optical element layer 5 (optical element 7) picked up by each pickup portion 51 of the pickup unit 50 is moved to the bonding layer 110 provided on the mounting substrate 100 and mounted Set. The bonding layer 110 is arranged and arranged in the same shape, size, and interval as the optical element layer 5 (optical element 7).

In the mounting step ST15, each optical element layer 5 (optical element 7) transferred to the bonding layer 110 of the mounting substrate 100 is bonded to the mounting substrate 100 via the bonding layer 110 and mounted.

In this way, in the mounting step ST15, in this embodiment, the optical element layers 5 (optical elements 7) protruding from the bonding layer 12 are all transferred to the mounting substrate 100 by the pickup portions 51 of the pickup unit 50. The optical element layer 5 (optical element 7) is transferred efficiently. In addition, the mounting step ST15 of the present invention is not limited to the second modification, and the optical element layers 5 (optical elements 7) protruding from the bonding layer 12 may be moved one by one to the mounting substrate 100 by using one pick-up portion 51. . In this case, the accuracy of the transfer of each optical element layer 5 (optical element 7) can be improved.

The transfer method of the optical element 7 of the optical element wafer 1 of the second modification includes a mounting step ST15, which picks up the optical element layer 5 (optical element 7) from the transfer substrate 11 and mounts it after the buffer layer removal step ST14. The substrate 100.

In addition, the present invention is not limited to the above-mentioned embodiment. That is, various modifications can be added and implemented without departing from the gist of the present invention.

1: Optical component wafer 2: Epitaxy substrate 3: positive 4: Buffer layer 5: Optical element layer 7: Optical components 8: back 10: Composite substrate 11: Move the substrate 12: Bonding layer 34: Pulse laser beam

FIG. 1 is a perspective view of an optical element wafer to be transferred including the optical element transfer method of the embodiment. FIG. 2 is a cross-sectional view of the optical element wafer of FIG. 1. FIG. FIG. 3 is a flow chart showing the method of transferring the optical element according to the embodiment. FIG. 4 is a cross-sectional view showing a state of the transfer substrate bonding step of FIG. 3. FIG. FIG. 5 is a cross-sectional view showing a state after FIG. 4 in the transfer substrate bonding step of FIG. 3. Fig. 6 is a cross-sectional view showing an example of the step of destroying the buffer layer of Fig. 3. FIG. 7 is a cross-sectional view showing a state in the step of transferring the optical element layer of FIG. 3. FIG. Fig. 8 is a cross-sectional view showing an example of the buffer layer removal step of Fig. 3. Fig. 9 is a flowchart showing a method of transferring an optical element according to the first modification. FIG. 10 is a cross-sectional view of the optical element wafer before the step of forming the micro light emitting diode of FIG. 9 is implemented. FIG. 11 is a cross-sectional view showing an example of the steps of forming the micro light emitting diode of FIG. 9. Fig. 12 is a flowchart showing a method of transferring an optical element according to a second modification. Fig. 13 is a cross-sectional view showing an example of the installation procedure of Fig. 12. Fig. 14 is a cross-sectional view showing a state after Fig. 13 in the installation step of Fig. 12;

ST11: Transfer substrate bonding step

ST12: buffer layer destruction step

ST13: Optical element layer transfer steps

ST14: Buffer layer removal step

Claims (3)

A method for transferring an optical element, which transfers an optical element of an optical element wafer with an optical element layer laminated on the front surface of an epitaxial substrate via a buffer layer to a transfer substrate, which is characterized in that it comprises: A transfer substrate bonding step, bonding the transfer substrate through the bonding layer on the front surface of the optical element layer of the optical element wafer to form a composite substrate; The buffer layer destruction step, after the transfer substrate bonding step, irradiate a pulse of a wavelength that is transparent to the epitaxial substrate and absorbs the buffer layer from the back side of the epitaxial substrate of the optical element wafer constituting the composite substrate The laser beam destroys the buffer layer; and An optical element layer transfer step, after the buffer layer destruction step, peel the epitaxial substrate from the optical element layer and transfer the optical element layer to the transfer substrate; After the optical element layer transfer step, the pulsed laser beam having a wavelength that absorbs the buffer layer remaining on the optical element layer is irradiated to perform a buffer layer removal step for removing the remaining buffer layer. The method for transferring a light element according to claim 1, which includes a micro light emitting diode forming step, which divides the light element layer into a wafer size and forming a micro light emitting diode before the transfer substrate bonding step. The optical element transfer method of claim 1 or 2, which includes a mounting step of picking up the optical element layer from the transfer substrate and mounting on the mounting substrate after the buffer layer removal step.

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