LASER LIFT-OFF METHOD, METHOD FOR PRODUCING A RECEIVER SUBSTRATE, DEVICE FOR LASER LIFT-OFF AND PHOTOMASK

Abstract

The present invention provides a laser lift-off method for transferring objects from a first substrate, which is provided with the objects to be transferred, to a second substrate by means of laser lift-off. The method comprises a single transfer step in which the objects to be transferred are removed from the first substrate by irradiating the interfaces between the objects to be transferred and the first substrate with a laser beam and transferred to the second substrate all at once. In the single transfer step, only a portion of an interface between each of the objects to be transferred and the first substrate is irradiated with the laser beam. This method makes it possible to provide a laser lift-off process that can prevent damage to the objects to be transferred during the transfer.

Description

TECHNICAL FIELD

[0001] The present invention relates to a laser lift-off method, a method for producing a receiver substrate, a laser lift-off device and a photomask. STATE OF THE ART

[0002] In recent years, nitride semiconductor optical devices have been increasingly used for liquid crystal display backlighting and digital signage.

[0003] For example, numerous optical devices are manufactured on a sapphire substrate using a semiconductor process. Millions of micro-LEDs are required to produce a 4-inch display substrate with LEDs, each measuring 100 μm square or less, called micro-LEDs. The micro-LED, a tiny device measuring a few tens of micrometers in length, is used after being separated from the sapphire substrate, which is an epitaxial substrate.

[0004] Separation is generally achieved by bonding a carrier substrate as a donor precursor substrate to optical devices arranged on a sapphire substrate and separating the optical devices from the sapphire substrate by laser lift-off (LLO). This makes it possible to obtain a donor substrate on whose surface a large number of optical devices are provided.

[0005] Such a method can be applied not only to those related to optical devices but also to the manufacture of a donor substrate on the surface of which objects to be transferred, such as minute semiconductor devices, are provided.

[0006] Furthermore, objects to be transferred on a donor substrate, for example, may be transferred to a receiving substrate to be arranged correspondingly to a circuit board of a product, and may then be transferred from the receiving substrate to another circuit board, such as the circuit board of the product, due to the use of a stamping process.

[0007] For example, Patent Document 1 proposes a method in which objects to be transferred on a donor substrate are precisely transferred to a receiving substrate using irradiation with a laser beam.

[0008] A laser lift-off process is a technique by which objects to be transferred from a substrate provided with the objects to be transferred (a first substrate) are removed by irradiating an interface between the objects to be transferred and the first substrate with a laser beam and then transferring the removed objects to be transferred to another substrate (a second substrate).

[0009] Such a laser lift-off procedure is roughly divided into gap laser lift-off (gap LLO) and contact laser lift-off (contact LLO). These techniques are described below with reference to Fig. 21 and Fig. 22 described schematically.

[0010] In the Gap-LLO, first, as in Fig. As shown in Fig. 21(a), a first substrate (e.g., a sapphire substrate) 1 provided with objects to be transferred (e.g., micro-LED chips) 10, and a second substrate (e.g., a quartz substrate) 2 provided with an adhesive layer 3 on its surface are arranged opposite to each other with a distance between the objects 10 to be transferred and the adhesive layer 3, that is, with a gap. In this state, the interface 11 between each of the objects 10 to be transferred and the first substrate 1 is irradiated with a laser beam 20R from a laser oscillator 110 through a surface opposite to a surface of the first substrate 1 provided with the objects 10 to be transferred. Generally, the entire surface of the interface 11 between each of the objects 10 to be transferred and the first substrate 1 is sequentially irradiated with the laser beam 20R.

[0011] For example, if the first substrate is a sapphire substrate provided with the objects 10 to be transferred and having a GaN layer on the interface 11, the GaN layer is decomposed (ablated) by irradiation with the laser beam 20R. When the bonding force (adhesion force, adhesive force, etc.) between the objects 10 to be transferred and the first substrate 1 becomes weak due to the ablation, the objects 10 to be transferred detach from the first substrate 1. Furthermore, the decomposition of the GaN layer generates a gas (for example, nitrogen gas). The removed objects 10 to be transferred are transferred to the second substrate 2 with a propulsive force due to the pressure of this gas, move in a space between the first substrate 1 and the second substrate 2, and reach the adhesive layer 3 on the second substrate 2. In this way, the objects 10 to be transferred are transferred to the second substrate 2.

[0012] Next, as in Fig. 21(b), the first substrate 1 is removed. Thus, the transfer of the objects 10 to be transferred from the substrate 1 to the substrate 2 is completed.

[0013] In contact LLO, the process is initially the same as in gap LLO, except that a first substrate 1 provided with objects 10 to be transferred and a second substrate 2 provided with an adhesive layer 3 on its surface are arranged so that they face each other and the objects 10 to be transferred and the adhesive layer 3 are arranged as in Fig. 22(a). By removing the first substrate as shown in Fig. 22(b), after irradiation with the laser beam 20R, the transfer of the objects 10 to be transferred from the substrate 1 to the substrate 2 is completed. LITERATURE LISTPATENT LITERATURE

[0014] Patent Document 1: JP 2020-4478 A SUMMARY OF THE INVENTION TECHNICAL PROBLEM

[0015] Traditionally, objects being transferred were sometimes broken due to gap LLO transfer. Even with contact LLO transfer, chipping of the transferred objects sometimes occurred.

[0016] The present invention was made to solve the above-mentioned problem. An object of the present invention is to provide a laser lift-off method that can prevent damage to the objects to be transferred during transfer, a method for producing a receiving substrate that can produce a receiving substrate provided with objects to be transferred without damage, a laser lift-off device that can prevent the occurrence of damage to the objects to be transferred during transfer, and a photomask used in laser lift-off that can reduce the occurrence of damage to the objects to be transferred during transfer. SOLUTION TO THE TASK

[0017] In order to achieve the above-described object, the present invention provides a laser lift-off method for transferring objects to be transferred from a first substrate provided with the objects to be transferred to a second substrate due to laser lift-off, comprising a one-time transfer step in which the objects to be transferred are removed from the first substrate by irradiating the interfaces between the objects to be transferred and the first substrate with a laser beam and are transferred to the second substrate at once, wherein in the transfer step which takes place at a time, only a portion of an interface between each of the objects to be transferred and the first substrate is irradiated with the laser beam.

[0018] Here, "only a portion of an interface is irradiated with the laser beam" means that the irradiation of each interface with the laser beam is performed at a portion of each interface. That is, the irradiation of each interface with the laser beam only needs to be performed at a portion of each interface, and at the same time, an area that does not have any objects to be transferred can be irradiated with the laser beam. Accordingly, the present invention also includes an embodiment in which, as described later, Fig. 4, Fig. 5 and Fig. 6, an area without objects to be transferred, such as an area between adjacent objects to be transferred, is also irradiated with the laser beam.

[0019] In a single transfer step, by irradiating a portion (hereinafter also referred to as "partial irradiation") of the interface between each of the objects to be transferred and a first substrate with the laser beam, it is possible to reduce an impact generated during laser lift-off and reduce the occurrence of damage such as cracking and chipping on the objects to be transferred during transfer.

[0020] It is preferred that the method further includes, prior to the all-in-one transfer step, a preparatory irradiation step of irradiating the interface between each of the objects to be transferred and the first substrate with a laser beam having a lower energy than that in the all-in-one transfer step, which is insufficient to remove the objects to be transferred from the first substrate.

[0021] By performing such a preparatory irradiation step in the all-in-one transfer step, it is possible to further reduce the impact on the objects to be transferred and prevent positional deviation of the objects to be transferred. Furthermore, it is possible to prevent the occurrence of splitting and thus reduce the formation of residues in the all-in-one transfer step when a material with a crystal structure, such as a GaN layer, is used as the ablation layer.

[0022] In this case, it is particularly preferable that in the preparatory irradiation step, only a portion of the interface between each of the objects to be transferred and the first substrate is irradiated with the laser beam.

[0023] By performing partial irradiation also in the preparatory irradiation step, it is possible to further prevent the occurrence of cleavage and consequently reduce the formation of residues when a material with a crystal structure, such as a GaN layer, is used as the ablation layer.

[0024] For example, the preparatory irradiation step can be performed 1 to 4 times.

[0025] The number of times the preparatory irradiation step is performed is not particularly limited, but repeating this step facilitates the control of the impact effect on the objects to be transferred during the laser lift-off while keeping the speed of the laser lift-off appropriate.

[0026] For example, it is preferable that in each of the preliminary irradiation step and the all-at-once transfer step, irradiation with the laser beam is performed such that an irradiated area with the laser beam is 10 to 60% of an area of ​​the interface between each of the objects to be transferred and the first substrate.

[0027] When an irradiated area by the partial irradiation in each of the preliminary irradiation step and the all-at-once transfer step is within the range of 10 to 60% of the area of ​​the interface between each of the objects to be transferred and the first substrate, it is possible to efficiently transfer the objects to be transferred from the first substrate to the second substrate and provide a margin for irradiation errors with the laser beam.

[0028] Areas irradiated with the laser beam are preferably adjusted to be different between the preparatory irradiation step and the all-in-one transfer step.

[0029] By making the irradiated areas different between the preliminary irradiation step and the all-in-one transfer step, it is possible to reduce the occurrence of non-irradiated areas between objects to be transferred and the first substrate and to reduce the occurrence of cleavage when a material having a crystal structure, such as a GaN layer, is used as the ablation layer.

[0030] It is preferable that the preliminary irradiation step and the simultaneous transfer step are performed such that there is no overlap of the irradiated areas, or such that an overlap of the irradiated areas is 10% or less of the area of ​​the interface between each of the objects to be transferred and the first substrate.

[0031] The irradiated area in the preliminary irradiation step and that in the transfer step can overlap. By keeping the overlap of the irradiated areas to 10% or less, it is possible to suppress excessive deterioration of the objects to be transferred and create a margin for laser beam irradiation errors.

[0032] In total, the irradiated areas of the preparatory irradiation step and the simultaneous transfer step may amount to 40 to 100% of an area of ​​the interface between each of the objects to be transferred and the first substrate.

[0033] By irradiating 40% or more of the interface area between each of the objects to be transferred and the first substrate as the sum total of the preliminary irradiation step and the transfer step at once, the transfer of the objects can be performed more efficiently. Furthermore, the entire area, i.e., 100% of the interface area between each of the objects to be transferred and the first substrate can be irradiated with the laser beam as the sum total of the preliminary irradiation step and the transfer step at once.

[0034] For example, laser powers can be adjusted to differ between the preparatory irradiation step and the all-in-one transfer step.

[0035] The energy of the laser beam for irradiation in the preparatory irradiation step can be lower than that in the all-in-one transfer step, for example, by making the laser powers different between the preparatory irradiation step and the all-in-one transfer step.

[0036] Alternately, a photomask may be provided having a first part with a first laser transmittance and a second part with a second laser transmittance less than the first laser transmittance, In the preparatory irradiation step, the irradiation with the laser beam can be carried out through the second part of the photomask, and In the transfer step, which takes place all at once, the irradiation with the laser beam can take place through the first part of the photomask.

[0037] In this way, the laser powers do not need to be different between the preparatory irradiation step and the all-in-one transfer step, and thus this is advantageous for mass production.

[0038] In the all-at-once transfer step, irradiation with the laser beam is preferably performed such that an irradiated area with the laser beam is 40 to 90% of an area of ​​the interface between each of the objects to be transferred and the first substrate.

[0039] If the laser irradiated area in the one-shot transfer step is within the above range, it is possible to reduce the occurrence of damage to the objects to be transferred while maintaining transfer efficiency.

[0040] In the all-at-once transfer step, the irradiation of the laser beam may be performed such that the laser-irradiated portions are formed in multiples at the interface between each of the objects to be transferred and the first substrate.

[0041] A form of partial irradiation is not particularly limited, but sections irradiated with laser, for example, can be formed in many ways.

[0042] In this case, the irradiation with the laser beam in the all-in-one transfer step may be performed, for example, such that the laser-irradiated portions have at least one shape selected from the group consisting of a circular shape, an elliptical shape, and a polygonal shape.

[0043] The shape of the laser irradiated sections is not particularly limited, but it can be, for example, a circular shape, an elliptical shape or a polygonal shape.

[0044] Alternatively, in the one-time transfer step, the irradiation with the laser beam can be carried out in such a way that the laser-irradiated sections have a line shape.

[0045] The laser-irradiated sections may have a linear shape.

[0046] For example, the laser irradiated portions in the all-at-once transfer step may have a rectangular shape or a line shape, and the irradiation with the laser beam may be performed such that a longitudinal direction of the laser irradiated portions approximately coincides with the longitudinal direction of the objects to be transferred.

[0047] Alternatively, the laser irradiated portions in the all-at-once transfer step may have a rectangular shape or a line shape, and the irradiation of the laser beam may be performed such that a longitudinal direction of the laser irradiated portions approximately coincides with a short length direction of the objects to be transferred.

[0048] Alternatively, the laser-irradiated portions in the all-at-once transfer step may have a rectangular shape or a linear shape, and the irradiation with the laser beam may be carried out in such a way that the laser-irradiated portions come to lie on adjacent objects to be transferred.

[0049] As described above, the arrangement of the plurality of laser irradiated sections is not particularly limited with respect to the objects to be transferred.

[0050] In the all-at-once transfer step, irradiation of the laser beam may be performed such that non-irradiated portions at which the irradiation of the laser beam is not performed are formed in multiples at the interface between each of the objects to be transferred and the first substrate.

[0051] Partial irradiation can be performed in such a way that a plurality of non-irradiated sections are formed.

[0052] In this case, the irradiation with the laser beam in the all-in-one transfer step may be performed, for example, such that the non-irradiated portions have at least one shape selected from the group consisting of a circular shape, an elliptical shape, and a polygonal shape.

[0053] The shape of the non-irradiated sections is not particularly limited, but it can be, for example, a circular shape, an elliptical shape or a polygonal shape.

[0054] Alternatively, in the single transfer step, the laser beam can be irradiated in such a way that the non-irradiated sections have a line shape.

[0055] The non-irradiated sections may have a line shape.

[0056] For example, the non-irradiated portions in the all-at-once transfer step may have a rectangular shape or a line shape, and the irradiation with the laser beam may be performed such that a longitudinal direction of the non-irradiated portions approximately coincides with the longitudinal direction of the objects to be transferred.

[0057] Alternatively, the non-irradiated portions in the all-at-once transfer step may have a rectangular shape or a line shape, and the irradiation with the laser beam may be performed such that a longitudinal direction of the non-irradiated portions approximately coincides with a short length direction of the objects to be transferred.

[0058] Alternatively, the non-irradiated portions in the all-in-one transfer step may have a rectangular shape or a line shape, and the irradiation with the laser beam may be performed such that the non-irradiated portions are placed on adjacent objects to be transferred.

[0059] As described above, the arrangement of the plurality of non-irradiated portions is not particularly limited with respect to the objects to be transferred.

[0060] As the objects to be transferred, for example, the objects selected from the group consisting of semiconductor chips, LED chips, resin material films and inorganic films can be transferred.

[0061] In the present invention, the objects to be transferred are not particularly limited, but may be, for example, those mentioned above.

[0062] Furthermore, the present invention provides a method for producing a receiver substrate provided with objects to be transferred, the method comprising: a step of providing a donor substrate provided with the objects to be transferred and a receiver precursor substrate; and a step of obtaining the receiving substrate by transferring the objects to be transferred from the donor substrate to the receiving precursor substrate due to the laser lift-off, wherein in the step of obtaining the receiver substrate due to the laser lift-off method of the present invention, the objects to be transferred are subjected to a laser lift-off from the donor substrate as the first substrate to the receiver precursor substrate as the second substrate.

[0063] According to the method for producing a receiver substrate of the present invention, the receiver substrate can be obtained by transferring the objects to be transferred according to the laser lift-off method of the present invention; and thus, a receiver substrate provided with objects to be transferred that are free of damage can be produced. Furthermore, it is possible to improve the production yield of a receiver substrate.

[0064] Furthermore, the present invention provides a laser lift-off device for transferring objects to be transferred from a first substrate provided with the objects to be transferred to a second substrate due to laser lift-off, the device comprising: a laser oscillator; a table for supporting the first substrate and the second substrate while facing each other; and a photomask provided in an optical path between the laser oscillator and the table, wherein the laser oscillator, the photomask and the table are configured to irradiate interfaces between the objects to be transferred and the first substrate at once with a laser beam from the laser oscillator, and the photomask has a pattern for shaping the laser beam from the laser oscillator into such a shape that only a portion of an interface between each of the objects to be transferred and the first substrate is irradiated with the laser beam.

[0065] The laser lift-off device of the present invention can perform partial irradiation of each of the objects to be transferred when the objects to be transferred are transferred at once to a second substrate due to laser lift-off. As a result, it is possible to reduce the impact generated during laser lift-off and reduce the occurrence of damage such as cracking and chipping on the objects to be transferred during transfer.

[0066] The laser lift-off device is preferably further configured to be able to switch energy of the laser beam for irradiating the interfaces between the objects to be transferred and the first substrate with the laser beam between an energy that is not sufficient to remove the objects to be transferred from the first substrate and an energy that is sufficient to remove the objects to be transferred from the first substrate.

[0067] By using such a device, partial irradiation can be performed on a plurality of stages, and the impact on the objects to be transferred can be further reduced when the objects to be transferred are transferred all at once to a second substrate by laser lift-off. Furthermore, when a material with a crystal structure, such as a GaN layer, is used as the ablation layer to transfer the objects to be transferred all at once to a second substrate by laser lift-off, it is possible to prevent the occurrence of cleavage and thus reduce the generation of residue.

[0068] In this case, the pattern of the photomask may, for example, include a first pattern and a second pattern, and the laser lift-off device may be configured: in order to be able to irradiate the interfaces between the objects to be transferred and the first substrate with the laser beam through the first pattern at once with the energy sufficient to remove the objects to be transferred from the first substrate, and in order to be able to irradiate the interfaces between the objects to be transferred from the first substrate with the laser beam through the second pattern at once with an energy which is insufficient to remove the objects to be transferred from the first substrate.

[0069] Such a laser lift-off device can perform partial irradiation on a variety of tables without changing the laser power.

[0070] Furthermore, the present invention provides, as the photomask of the first embodiment, a photomask used in a laser lift-off method in which objects to be transferred are transferred from a first substrate provided with the objects to be transferred to a second substrate due to the laser lift-off, wherein the photomask is configured so that an interface between each of the objects to be transferred and the first substrate is irradiated with a received laser beam at once, and the photomask has a pattern to shape the laser beam such that only a portion of the interface between each of the objects to be transferred and the first substrate is to be an irradiated portion.

[0071] Here, "only one proton ... shall be an irradiated portion" means that an irradiated area with the laser beam of each interface is a portion of each interface. That is, an irradiated area with the laser beam need only be a portion of each interface, and an area that does not have objects to be transferred may also be included in the pattern as well as the irradiated area. Accordingly, the present invention includes an embodiment in which the photomask has a pattern such that, as in the examples described later, Fig. 4, Fig. 5 and Fig. 6, an area without objects to be transferred, such as a space between adjacent objects to be transferred, is also irradiated with the laser beam.

[0072] Using such a photomask, partial irradiation of each object to be transferred can be achieved when the objects to be transferred are transferred simultaneously to a second substrate due to laser lift-off. This makes it possible to reduce the impact generated during laser lift-off and reduce the occurrence of damage such as cracking and chipping on the objects to be transferred during transfer.

[0073] For example, the patterning may be a pattern for shaping the laser beam so that the laser irradiated portions are formed in multiples.

[0074] Alternatively, the pattern is a pattern for shaping the laser beam such that non-irradiated portions where irradiation with the laser beam is not performed are formed in multiples at the interface between each of the objects to be transferred and the first substrate.

[0075] In this way, a pattern of the photomask for the first embodiment of the present invention may be one for forming multiple laser irradiated portions or one for forming multiple non-irradiated portions.

[0076] The photomask may include a first portion on which the pattern is formed and having a first laser transmittance, and a second portion having a second laser transmittance lower than the first laser transmittance.

[0077] A photomask for the first embodiment of the present invention may include two or more parts, each having a different laser transmittance from each other. By using such a photomask, it is possible to change the energy for irradiating the interface between each of the objects to be transferred and the first substrate without changing the laser power.

[0078] Furthermore, the present invention provides, as a photomask of the second embodiment, a photomask used in a laser lift-off method in which objects to be transferred are transferred from a first substrate provided with the objects to be transferred to a second substrate due to laser lift-off, comprising: a first part having a pattern for shaping a shape of a received laser beam into a patterned shape and a first laser transmittance; and a second part having a second laser transmittance that is less than the first laser transmittance.

[0079] By using such a photomask of the second embodiment, it is possible to perform partial irradiation against each of the objects to be transferred when the objects to be transferred are transferred at once onto a second substrate due to laser lift-off. Due to this, it is possible to reduce the impact generated during laser lift-off and reduce the occurrence of damage such as cracking and chipping on the objects to be transferred during transfer.

[0080] Furthermore, by using such a photomask, it is possible to change the laser energy for irradiating an interface between each of the objects to be transferred and the first substrate without changing the laser power. Accordingly, it is not necessary to incorporate a plurality of laser oscillators into a single laser lift-off device, to perform two laser beam irradiations using a single laser lift-off device while changing the laser power from its laser oscillator, or to manufacture two laser lift-off devices having laser oscillators with different laser powers, and it becomes possible to perform laser beam irradiation with multiple laser powers through a single laser beam operation. ADVANTAGEOUS EFFECTS OF THE INVENTION

[0081] As described above, the laser lift-off method of the present invention can reduce the occurrence of damage to the objects to be transferred during transfer.

[0082] Furthermore, the method for producing a receiver substrate of the present invention can produce a receiver substrate provided with objects to be transferred that have no damage.

[0083] Furthermore, by using the laser-laser lift-off device of the present invention, it is possible to implement a laser lift-off method that can reduce the occurrence of damage to the objects to be transferred during transfer.

[0084] And then, a photomask of the present invention can be a photomask for laser lift-off, which can reduce the occurrence of damage to objects to be transferred during transfer. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic diagram of the first example of the laser lift-off device according to the invention; Fig. 2 is a schematic representation of the second example of the laser lift-off device according to the invention; Fig. 3 is a schematic diagram showing the all-in-one transfer step in an example of the laser lift-off method according to the present invention; Fig. 4 is a schematic diagram showing some forms of partial irradiation in the all-in-one transfer step of the laser lift-off method according to the invention; Fig. 5 is a schematic diagram showing some examples of photomask patterns used in the laser lift-off method according to the present invention; Fig. 6 is a schematic diagram showing some examples of photomask patterns used in the laser lift-off method according to the present invention; Fig. 7 is a schematic diagram showing a preliminary irradiation step and a one-shot transfer step in an example of the laser lift-off method according to the present invention; Fig. Figure 8 is a photograph of a first substrate after the objects to be transferred have been Fig. 7 shown preparatory irradiation step and one-time transfer step; Fig. 9 is a photograph of a first substrate after objects to be transferred have been Fig. 3 shown in a single transfer step; Fig. 10 is a schematic diagram showing a mechanism of the Fig. 3 shows the single transfer step shown; Fig. Figure 11 is a schematic diagram showing the mechanisms of Fig. 7 shows the preparatory irradiation step and the simultaneous transfer step; Fig. 12 is a schematic diagram showing the preliminary irradiation step and the all-in-one transfer step in another example of the laser lift-off according to the present invention; Fig. 13 is an enlarged view of part XIII of the Fig. Photomask shown in 12. Fig. 14 is a schematic diagram showing the preliminary irradiation step and the all-in-one transfer step in another example of the laser lift-off according to the present invention; Fig. 15 is an enlarged view of part XV of the Fig. Photomask shown in 14. Fig. 16 is a schematic diagram showing the preliminary irradiation step and the all-in-one transfer step in another example of the laser lift-off according to the present invention; Fig. 17 is an enlarged view of part XII of the Fig. Photomask shown in 16. Fig. 18 is a schematic diagram showing an arrangement of objects to be transferred and a photomask in an example of the laser lift-off method according to the present invention; Fig. Fig. 19 is a schematic diagram showing an example of laser irradiated portions after partial irradiation using the method shown in Fig. 18 shown photomask was performed. Fig. 20 is a photograph of the first substrate after transfer was performed in Example 1; Fig. Figure 21 is a schematic diagram to describe conventional gap LLO; Fig. Figure 22 is a schematic diagram to describe contact LLO. DESCRIPTION OF EMBODIMENTS

[0085] As described above, it has been desired to develop: a laser lift-off method that can reduce the occurrence of damage to objects to be transferred during transfer; a method of manufacturing a receiver substrate, the method capable of manufacturing a receiver substrate provided with objects to be transferred without damage; a laser lift-off device that can reduce the occurrence of damage to objects to be transferred during transfer; and a photomask for laser lift-off that can reduce the occurrence of damage to objects to be transferred during transfer.

[0086] As a result of their diligent study of the above-described problems, the inventors found that, in transferring objects to be transferred by laser lift-off, by adopting an all-at-once transfer step in which objects to be transferred are transferred all at once due to the laser lift-off and irradiating only a portion of the interface between each of the objects to be transferred and the first substrate with a laser beam in the all-at-once transfer step, it is possible to prevent positional deviation of the objects to be transferred that occurs in the laser lift-off, reduce the impact that occurs in the laser lift-off, and reduce the occurrence of damages such as cracking and chipping of objects to be transferred during transfer, and then completed the present invention.

[0087] That is, the present invention relates to a laser lift-off method for transferring objects to be transferred from a first substrate provided with the objects to be transferred to a second substrate due to laser lift-off, comprising a one-time transfer step in which objects to be transferred are removed from a first substrate by simultaneously irradiating the interfaces between the objects to be transferred and the first substrate with a laser beam and are transferred all at once to a second substrate, wherein in the transfer step which takes place at a time, only a portion of an interface between each of the objects to be transferred and the first substrate is irradiated with the laser beam.

[0088] Furthermore, the present invention relates to a method for producing a receiver substrate provided with objects to be transferred, the method comprising: a step of providing a donor substrate provided with the objects to be transferred and a receiver precursor substrate; and a step of obtaining the receiving substrate by transferring the objects to be transferred from the donor substrate to the receiving precursor substrate due to the laser lift-off, wherein in the step of obtaining the receiver substrate due to the laser lift-off method of the present invention, the objects to be transferred are subjected to a laser lift-off from the donor substrate as the first substrate to the receiver precursor substrate as the second substrate.

[0089] Furthermore, the present invention relates to a laser lift-off device for transferring objects to be transferred from a first substrate provided with the objects to be transferred to a second substrate due to laser lift-off, the device comprising: a laser oscillator; a table for supporting the first substrate and the second substrate while facing each other; and a photomask provided in an optical path between the laser oscillator and the table, wherein the laser oscillator, the photomask and the table are configured to irradiate interfaces between the objects to be transferred and the first substrate at once with a laser beam from the laser oscillator, and the photomask has a pattern for shaping a laser beam from the laser oscillator into such a shape that only a portion of an interface between each of the objects to be transferred and the first substrate is irradiated with the laser beam.

[0090] Furthermore, the present invention relates to a photomask which is used in a laser lift-off method in which objects to be transferred are transferred from a first substrate provided with the objects to be transferred to a second substrate due to laser lift-off, wherein the photomask is configured so that an interface between each of the objects to be transferred and the first substrate is irradiated with a received laser beam at once, and the photomask has a pattern to shape the laser beam such that only a portion of the interface between each of the objects to be transferred and the first substrate is to be an irradiated portion.

[0091] Furthermore, the present invention relates to a photomask used in a laser lift-off method in which objects to be transferred are transferred from a first substrate provided with the objects to be transferred to a second substrate due to laser lift-off, comprising: a first part having a pattern for shaping a shape of a received laser beam into a patterned shape and a first laser transmittance; and a second part having a second laser transmittance that is less than the first laser transmittance.

[0092] Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto. [Laser lift-off device]

[0093] Fig. 1 shows a schematic representation of the first example of the laser lift-off device according to the invention.

[0094] A laser lift-off device 100, which in Fig. 1 is configured to perform Gap-LLO.

[0095] The laser lift-off device 100 includes a laser oscillator 110, a stage 160, and a photomask 130. The laser lift-off device 100 further includes, as optional components, a shaping optical system 120, a reflecting mirror 140, a reduced projection lens 150, an alignment camera 170, and a controller 180.

[0096] The table 160 includes an upper table 161 having an opening 161a, which supports a first substrate 1, and a lower table 162, which supports a second substrate 2. The first substrate 1 includes a plurality of objects 10 to be transferred, similar to a first substrate 1, which in Fig. 21(a) and Fig. 22(a). The table 160 is configured to support the first substrate 1 and the second substrate 2 while facing each other.

[0097] The laser oscillator 110 is configured to oscillate a laser beam 20a. In the laser lift-off device 100, the components are arranged to form an optical path in which the laser beam emitted by the laser oscillator 110 passes through the shaping optical system 120 to be shaped into a laser beam 20b; the laser beam 20b passes through the photomask 130, where it is shaped into a laser beam 20c; the direction of the laser beam 20c is changed by the reflecting mirror 140; the laser beam 20c passes through the reduced projection lens 150 to become a laser beam 20; and the laser beam 20 passes through the opening 161a of the upper table 161 to reach the first substrate 1. That is, the photomask 130 is provided in an optical path between the laser oscillator 110 and the stage 160.

[0098] In the Fig. In the laser lift-off device 100 shown in Figure 1, the laser oscillator 110, the photomask 130, and the table 160 (upper table 161 and lower table 162) are configured to irradiate interfaces between the objects 10 to be transferred and the first substrate 1 with the laser beam 20 from the laser oscillator 110 at once.

[0099] The optical path of the laser beam emitted from the laser oscillator 110 is described below.

[0100] The laser beam 20a emitted by the laser oscillator 110 is, for example, an excimer laser beam.

[0101] The shaping optical system 120, which is an optional component, shapes an irradiation shape of the laser beam 20a emitted from the laser oscillator 110, for example, as shown in Fig. 1(a), into a rectangular irradiation shape, for example as shown in Fig. 1(b), and then the shaped laser beam is emitted as laser beam 20b. Laser beam 20b, which has a rectangular irradiation shape, can exhibit a uniform irradiation energy density and has a beam profile that exhibits, for example, a cylindrical shape. However, the shaping of the laser by the shaping optical system 120 is not limited to this.

[0102] The photomask 130 is configured to bring the irradiation beam of the incident laser beam 20b into a patterned shape, as shown in Fig. 1(c) to emit the shaped laser beam as laser beam 20c. More specifically, the photomask 130 has a pattern that shapes a laser beam from the laser oscillator 110 into a laser beam having a shape such that only a portion of an interface between each of the objects 10 to be transferred and the first substrate 1 is irradiated with the laser beam. Further, it can also be said that the photomask 130 is configured to irradiate the interface between each of the objects 10 to be transferred and the first substrate 1 with the received laser beam at once, and that the photomask 130 has a pattern for shaping the laser beam so that only a portion of the interface between each of the objects 10 to be transferred and the first substrate 1 becomes the irradiated area.

[0103] The photomask 130 may further include a pattern for shaping the laser beam so that an entire area of ​​the interface between each of the objects 10 to be transferred and the first substrate 1 becomes an irradiated area. Further details of the photomask 130 will be described later.

[0104] The laser beam 20c emitted from the photomask 130 changes its direction of travel through the reflection mirror 140 and enters the reduced projection lens 150. The reduced projection lens 150 reduces the irradiation shape of the incident laser beam 20c, for example, from the Fig. 1(d) shown in Fig. 1(e) and emits the laser beam as laser beam 20.

[0105] By incorporating the reduced-size projection lens 150 into the optical path, the energy of the laser beam 20b incident on the photomask 130 can be made smaller than the energy required to remove the objects 10 to be transferred from the first substrate 1. When the reduction magnification of the reduced-size optical projection lens 150 is N, the energy of the laser beam 20b received by the photomask 130 is 1 / (N 2) compared to the energy of the laser beam 20 required to remove the objects 10 to be transferred from the first substrate 1. This can prevent deterioration of the forming optical system 120 and the photomask 130 due to irradiation with a laser beam, as well as thermal drift due to the energy of the laser beam 20b, suppressing the thermal expansion of the photomask 130, and highly precise transfers can be performed even after a prolonged laser lift-off. Furthermore, the influence of particles on the photomask 130 can also be reduced.

[0106] The alignment camera 170 and the controller 180 are configured to monitor the areas irradiated with the laser beam 20 on the first substrate 1 and to control the laser oscillator 110, the photomask 130, and the stage 160 (upper stage 161 and lower stage 162). For example, the controller 180 can move the photomask 130 to change the position of the pattern of the photomask 130 relative to the optical path of the laser beam 20b. Furthermore, the controller 180 can move and / or rotate the upper table 161 on the same plane to change the position of the first substrate 1, in particular the position of the objects 10 to be transferred with respect to the optical path of the laser beam 20. Furthermore, the controller 180 can move and / or rotate the lower table 162 on the same plane to change the position of the second substrate 2 with respect to the optical path of the laser beam 20.

[0107] Furthermore, the controller 180 may control the laser lift-off device 100 to implement the laser lift-off method of the present invention, as described later.

[0108] In the Fig. In the laser lift-off device 100 shown in Figure 1, the laser oscillator 110, the photomask 130, the alignment camera 170, the upper table 161 and the lower table 162 are each connected to the controller 180 via a communication line 18.

[0109] The laser-laser lift-off device 100 of the present invention is not limited to a device that performs Gap-LLO as shown in Fig. 1, but can also be a device that performs contact LLO.

[0110] Fig. Figure 2 is a schematic representation of a second example of the laser lift-off device according to the invention. Fig. The laser lift-off device 100 shown in Figure 2 is configured to perform contact LLO. Fig. 2 is the same as the laser lift-off device 100 shown in Fig. 1, except that the table 160 has an opening 160a and supports the first substrate 1 and the second substrate 2, while the objects 10 to be transferred on the first substrate maintain contact with the second substrate 2. [Laser lift-off procedure]

[0111] The following is an example of the laser lift-off method according to the invention using the method described in Fig. 1. However, the laser lift-off method according to the invention is not limited to one that uses the laser lift-off device 100 shown in Fig. 1 shown laser lift-off device 100, and can also be carried out with the Fig. 2 shown laser lift-off device 100 or other devices.

[0112] The laser lift-off method according to the invention includes a one-shot transfer step using partial irradiation, which is described below with reference to Fig. 3 is described.

[0113] Fig. 3(a) is a schematic cross-sectional view showing a concept of irradiation with a laser beam in the all-at-once transfer step in an example of the laser lift-off method according to the present invention. Fig. 3(b) is a diagram showing the positional relationship between a pattern of the photomask and one of the objects to be transferred during the Fig. 3(a) shows the irradiation with a laser beam.

[0114] In this example, a laser beam 20a emitted by the Fig. 1, is formed into a laser beam 20b by the forming optical system 120. The laser beam 20b enters the Fig. 3(a) and Fig. 3(b) shown photomask 130.

[0115] The Fig. 3(a) and Fig. 3(b) includes a laser-transmissive base material 131 and a pattern-forming layer 132 formed on the base material 131. As shown in Fig. As shown in Fig. 3(b), a pattern 31 including a plurality of openings 132a is formed in the pattern forming layer 132.

[0116] The portion not corresponding to the openings 132a of the pattern-forming layer 132 blocks the laser beam. Therefore, only the components of the laser beam 20b incident on the photomask 130 that pass through the portions corresponding to the openings 132a are transmitted through the photomask 130. As a result, a laser beam (which is Fig. 1), which has an irradiation shape with a pattern 31, is emitted from the photomask 130. Next, the laser beam 20c, although in Fig. 3 not shown, in the Fig. 1 shown reduced projection lens 150. In the reduced projection lens 150, the laser beam 20c is reduced, while the irradiation form is the one shown in Fig. 3(b) and is emitted as the laser beam 20.

[0117] The laser beam 20 emitted by the reduced projection lens 150 is incident on the surface of the first base material 1 opposite the objects 10 to be transferred. The laser beam 20 passes through the first base material 1 and reaches the interface 11 between the first base material 1 and the objects 10 to be transferred.

[0118] Here, the term "interface" does not refer to a strict boundary surface, but rather to a region that undergoes decomposition or similar degradation upon irradiation with a laser beam. Therefore, it can also be referred to as an ablation layer.In particular, it includes: an embodiment in which at least a portion of the side of the first substrate 1 with the objects to be transferred 10 is an ablation layer; an embodiment in which the side with the objects to be transferred 10 has an ablation layer formed on the first substrate 1; an embodiment in which at least a portion of the side in contact with the first substrate 1 of the objects to be transferred 10 is an ablation layer; an embodiment in which the side in contact with the first substrate 1 of the objects to be transferred 10 has an ablation layer formed; and an embodiment in which an ablation layer is arranged between the first substrate 1 and the objects to be transferred 10. The ablation layer can be part of the first substrate 1 or part of the objects to be transferred 10. The ablation layer can be provided separately from the first substrate 1 and the objects to be transferred 10.

[0119] Although Fig. 3 shows only one of the objects 10 to be transferred, the interface 11 between the objects 10 to be transferred and the first substrate 1 in the laser lift-off method according to the invention is irradiated with the laser beam 20 in the all-in-one transfer step, for example using a pattern 31 as in Fig. 4(a) or Fig. 4(b). However, the objects 10 to be transferred do not necessarily have to be adjacent to one another, as shown. For example, the objects 10 to be transferred can be arranged separately from one another without bordering one another.

[0120] As described above, the laser beam 20 has an irradiation pattern with the pattern 31 of the photomask 130. Therefore, as shown in Fig. 3(a) and Fig. 3(b), not the entire area of ​​the interface 11 between each of the objects 10 to be transferred and the first substrate 1 is irradiated with the laser beam 20, but only sections 11a of the interface 11 are irradiated with the laser beam 20. This means that in the laser lift-off method according to the invention, only sections 11a of the interface 11 between each of the objects 10 to be transferred and the first substrate 1 are irradiated with the laser beam 20 in the transfer step that takes place all at once (partial irradiation).

[0121] In the transfer step which takes place all at once, the objects 10 to be transferred are removed from the first substrate 1 due to such partial irradiation of the objects 10 to be transferred with the laser beam 20.

[0122] The energy required for removal is energy that can weaken bonding forces (e.g., adhesion force or joining force) between the objects 10 to be transferred and the first substrate 1, thus separating the objects 10 to be transferred from the first substrate 1. For example, if a GaN layer is present at the interface between the objects 10 to be transferred and the first substrate 1, it is necessary to decompose (ablate) the GaN layer to remove the objects 10 to be transferred. The laser energy density required in this case is high. In addition, the decomposition of the GaN layer generates nitrogen gas. The pressure of the generated nitrogen gas becomes a propulsive force, and the objects 10 to be transferred, which have been separated from the first substrate 1, are moved to the second substrate 2. This completes the transfer.

[0123] Although GaN is difficult to decompose, it decomposes quickly when the energy exceeds a threshold. Therefore, in the all-in-one transfer step, as shown in Fig. As shown in Figure 22, when the entire area of ​​the interface 11 between the objects 10 to be transferred and the first substrate 1 is irradiated with the laser beam 20R having an energy capable of separating the objects 10 to be transferred from the first substrate 1, a large amount of nitrogen gas is rapidly generated, and the ejection vector due to the generated gas is excessively large. As a result, the objects 10 to be transferred, which have been separated from the first substrate 1, are subjected to excessive pressure or have an excessively high initial velocity, and consequently collide with the surface of the second substrate 2 due to a very large ejection vector from the first substrate 1 to the second substrate 2.As a result, the objects 10 to be transferred are likely to crack while being transferred from the first substrate 1 to the second substrate 2, or the objects 10 to be transferred are likely to crack and chip when reaching the second substrate 2. Furthermore, due to the excessive ejection vector, it becomes difficult to control the movement of the objects 10 to be transferred onto the second substrate 2, and unintentional positional deviation of the objects 10 to be transferred is likely to occur when the objects to be transferred onto the second substrate 2.

[0124] In contrast, in the laser lift-off method of the present invention, by performing partial irradiation in the all-at-once transfer step, irradiating only a portion of the interface 11 between each of the objects 10 to be transferred and the first substrate 1 with the laser beam 10 as described above, the amount of gas generated when the objects 10 to be transferred are removed from the first substrate 1 is reduced, and the pressure exerted on the objects 10 to be transferred removed from the first substrate 1 can be reduced. As a result, the propulsive force imparted to the objects 10 to be transferred removed from the first substrate 1 can be moderately reduced, and the impact caused by the contact between the objects 1 to be transferred and the second substrate 2 can be reduced.Furthermore, the objects 10 to be transferred can be moved directly from the first substrate 1 to the second substrate 2 after removal, and it is possible to perform the lift-off process with high accuracy of the transferred position.

[0125] As described above with an example in which the GaN layer decomposes during the removal of the objects to be removed, since laser lift-off removal relies on ablation, the problem that the ejection vector becomes too large will inevitably arise in the case of irradiation of the entire surface as in the above example. On the other hand, in the laser lift-off method according to the present invention, since this ejection vector is kept small by performing partial irradiation in the all-at-once transfer step, the objects 10 to be transferred can be transferred while preventing damage such as cracking and chipping to the objects 10 to be transferred, regardless of the combination of the substrate 1 and the objects 10 to be transferred.In addition, although the application of partial irradiation for laser lift-off using ablation is described here, even in the case of transfer methods in which the propulsion force is imparted due to something other than ablation to objects to be transferred by irradiation with a laser beam, the propulsion force can be reduced by the partial irradiation with the laser beam, which can lead to improved transfer accuracy.

[0126] Furthermore, even when transmitting by contact LLO using the Fig. In the laser lift-off device 100 shown in Figure 2, cracking or chipping due to an excessively large ejection vector can occur, as described above, when the entire surface is irradiated. According to the laser lift-off method of the present invention, even in contact LLO, the objects 10 to be transferred can be transferred while preventing damage such as cracking or chipping of the objects 10 to be transferred.

[0127] Furthermore, when decomposition products are generated by irradiation with a laser beam, the amount of the generated products can be reduced and the subsequent cleaning process can be simplified.

[0128] Various modifications can be made to the laser lift-off method and apparatus of the present invention. Some embodiments are described below. [Laser irradiated section and non-irradiated section]

[0129] In the laser lift-off method according to the invention, only a portion of the interface 11 between each of the objects 10 to be transferred and the first substrate 1 is partially irradiated with the laser beam 20; and thus, a laser irradiated portion where irradiated with the laser beam 20 and a non-irradiated portion where not irradiated with the laser beam 20 are formed.

[0130] For example, the portions corresponding to the openings 132a of the pattern 31 of the photomask 130 shown in Fig. 4(a) and Fig. 4(b) shall be the laser irradiated portions, and the portions corresponding to the non-openings 132b except for the openings 132a of the pattern 31 shall be the non-irradiated portions.

[0131] Although the embodiment of the partial irradiation is not particularly limited, the irradiation with the laser beam 20 may be carried out so that the laser irradiated portions are formed in multiples, as shown in Fig. 4(a) and Fig. 4(b) shown.

[0132] The shape of the laser irradiated section can be changed as required by, for example, the pattern 31 of the photomask 130.

[0133] Fig. 5(a) to 5(d) schematically show some examples of the pattern of the photomask that can be used to form a plurality of laser irradiated portions in the present invention.

[0134] For example, the openings 132a of the photomask 130, as shown in Fig. 5(a) and Fig. 5(b), can be executed in a circular manner. In Fig. 5(a), the circular openings 132a are arranged offset, i.e. alternately. In Fig. 5(b), the circular openings 132a are arranged in a matrix, that is, in rows and columns. The shape of the staggered or matrix-arranged openings 132a is not limited to a circular shape, and may also be an elliptical shape, a polygonal shape, or other shapes, or a combination thereof.

[0135] Fig. 5(c) and (d) are examples in which the opening 132a of the photomask 130 has a rectangular shape. In Fig. 5(c), the longitudinal directions of a plurality of rectangular openings 132a approximately coincide with the direction of the short length of the objects 10 to be transferred. In Fig. 5(d), the longitudinal directions of a plurality of rectangular openings 132a approximately coincide with the longitudinal direction of the objects 10 to be transferred. Here, "approximately coincide" means that two straight lines coincide or the angle between them is 5 degrees or less.

[0136] Furthermore, Fig. 5(c), a plurality of rectangular openings 132a are arranged so as to extend over adjacent objects 10 to be transferred. By using such a photomask 130, it is possible to perform the irradiation with the laser beam 20 such that the laser-irradiated portions lie on the adjacent objects 10 to be transferred.

[0137] It should be noted that the Fig. 4 and Fig. In the examples of the photomask 130 shown in FIG. 5, the non-opening portion 132b is continuous except for the opening portions 132a. Therefore, a continuous non-irradiation region can be formed by irradiating a laser beam using such a photomask 130.

[0138] On the other hand, for example, using the Fig. 6(a) to 6(d) shown photomask 130, which is formed by inverting the pattern of the photomask shown in each example in Fig. 5, irradiation with the laser beam 20 can be performed so that a plurality of non-irradiation regions can be formed.

[0139] For example, as in Fig. 6(a) and Fig. 6(b), the non-opening portions 132a of the photomask 130 may be circular. In Fig. 6(a), the circular non-opening portions 132a are arranged in a staggered manner, that is, alternately. In Fig. 6(b), the circular non-opening portions 132a are arranged in a matrix, that is, in rows and columns. The shape of the non-opening portions 132a arranged in a staggered or matrix manner is not limited to a circular shape, and may also be an elliptical shape, a polygonal shape, or other shapes, or a combination thereof.

[0140] Fig. 6(c) and (d) are examples in which the non-opening portions 132a of the photomask 130 have a rectangular shape. In Fig. 6(c), the longitudinal directions of the plurality of rectangular non-opening portions 132a approximately coincide with the short length directions of the objects 10 to be transferred. In Fig. 6(d), the longitudinal directions of the plurality of rectangular non-opening portions 132a approximately coincide with the longitudinal directions of the objects 10 to be transferred. Here, "approximately coincide" means that two straight lines coincide or the angle between them is 5 degrees or less.

[0141] Furthermore, Fig. 6(c), a plurality of rectangular non-opening portions 132a are arranged so as to extend over adjacent objects 10 to be transferred. By using such a photomask 130, it is possible to perform the irradiation with the laser beam 20 so that the non-irradiated portions are located on adjacent objects to be transferred.

[0142] Note that the means for forming a plurality of irradiation regions and the means for forming a plurality of non-irradiation regions are not limited to the above examples.

[0143] Furthermore, in the all-at-once transfer step, irradiation with the laser beam is preferably performed such that an irradiated area with the laser beam is 40 to 90% of an area of ​​the interface 11 between each of the objects 10 to be transferred and the first substrate 1.

[0144] When the area of ​​the laser irradiated portion in the one-shot transfer step is within the above-mentioned range, the occurrence of damage to the objects 10 to be transferred can be reduced while maintaining transfer efficiency. [Multiple irradiation]

[0145] The laser lift-off method according to the invention further includes, before the above-described all-in-one transfer step, a preparatory irradiation step in which the interface 11 between each of the objects 10 to be transferred and the first substrate 1 is irradiated with a laser beam having a lower energy than that in the all-in-one transfer step and which is insufficient to remove the objects 10 to be transferred from the first substrate 1.

[0146] By performing such a preliminary irradiation step in the all-in-one transfer step, it is possible to further reduce the impact on the objects 10 to be transferred. Furthermore, it is also possible to prevent the occurrence of splitting and reduce the formation of residues when a material with a crystal structure, such as a GaN layer, is used as the ablation layer in the all-in-one transfer step.

[0147] In the preparatory irradiation step, the entire interface 11 between each of the objects 10 to be transferred and the first substrate 1 can be irradiated with the laser beam, but it is particularly advantageous that only a portion of the interface 11 is irradiated with the laser beam.

[0148] By performing partial irradiation also in the preparatory irradiation step, it is possible to further prevent the occurrence of cleavage and consequently the occurrence of residues can be reduced when a material having a crystal structure such as a GaN layer is used as an ablation layer.

[0149] In the preliminary irradiation step, the means for performing irradiation with the laser beam 20, which has a lower energy than in the all-in-one transfer step and is insufficient to remove the objects 10 to be transferred from the first substrate 1, is not particularly limited. This will be described below with reference to some examples. <Erstes Beispiel>

[0150] Fig. Figure 7(a) schematically shows a first example of the preparatory irradiation step in an example of the laser lift-off method according to the invention. Furthermore, Fig. 7(b) is an example of the one-shot transfer step that follows the procedure described in Fig. 7(a) is carried out.

[0151] In the Fig. In the preparatory irradiation step shown in Fig. 7(a), portions 11b of the interface 11 between each of the objects 10 to be transferred and the first substrate 1 are irradiated with the laser beam 20e having a lower energy than that of the laser beam 20 used in the step shown in Fig. 7(b) shown all at once, and which is not sufficient to remove the objects 10 to be transferred from the first substrate 1.

[0152] In this example, as Fig. 7, sections 11b, which are irradiated with the laser beam 20e in the preparatory irradiation step, differ from sections 11a, which are irradiated with the laser beam 20 in the all-in-one transfer step, at the interface 11. Such partial irradiation can be achieved by using the photomask 130, for example, as shown in Fig. 7, which has a second pattern 32 including openings 132c, which is different from a pattern (first pattern) 31 including openings 132a, and can be achieved by performing the preparatory irradiation step through the second patterns 32.

[0153] Fig. Figure 8 shows a photograph of the first substrate 1 after the objects 10 to be transferred have been Fig. 7 shown preparatory irradiation step and a single transfer step. Furthermore, Fig. 9 shows, for comparison, a photograph of a first substrate 1 after objects 10 to be transferred have been Fig. 3 shown in a single transfer step.

[0154] As can be seen from the comparison between Fig. 8 and Fig. 9, the first substrate 1 ( Fig. 8), from which the objects 10 to be transferred were transferred by the preparatory irradiation step and the transfer step taking place at once, no observations of residues were made on the first substrate 1 ( Fig. 9) remained for which the preparatory irradiation step was not carried out. The reason for this is explained below with reference to Fig. 10 and Fig. 11 described.

[0155] Fig. Figure 10 is a schematic diagram showing the mechanism of the Fig. 3 shows the single transfer step. Fig. Figure 11 is a schematic diagram showing the mechanism of the Fig. 7 shows the preparatory irradiation step and the simultaneous transfer step.

[0156] In the Fig. In the one-shot transfer step shown in Figure 3, as described above, a component (e.g., GaN) contained in the portions 11a of the interface 11 between the objects 10 to be transferred and the first substrate 1 is decomposed. Since the energy required to decompose GaN is high, the energy of the laser beam 20 incident on the portions 11a of the interface 11 is, for example, approximately 1.4 J / cm 2When the laser beam 20 irradiates the portions 11a of the interface 11 with such energy, the portions 11a are normal removal portions, but the energy is also transferred to portions adjacent to the portions 11a of the interface 11. Furthermore, the nitrogen gas generated by the decomposition of GaN creates a large ejection vector 14, which acts on the portions 11a of the interface 11 and generates stresses in the portions adjacent to the portions 11a of the interface 11. As a result, cleavage portions 11c are generated in the portions adjacent to the portions 11a of the interface 11.

[0157] The generated cleavage sections 11c remain as a residue 13 on the first substrate 1 and / or on the objects 10 to be transferred when the objects 10 to be transferred are removed from the substrate 1. Fig. The black objects shown in 9 are the residues.

[0158] In the Fig. On the other hand, in the preparatory irradiation step shown in Fig. 11(a), portions 11b of the interface 11 between the objects 10 to be removed and the first substrate 1 are irradiated with the laser beam 20e with an energy that is insufficient to remove the objects 10 to be transferred from the first substrate 1. With such irradiation with the laser beam, the GaN in the portions 11b is partially separated; but the separated portion is very thin; and the first substrate 1 and the objects 10 to be transferred remain loosely connected to each other. Furthermore, since the amount of decomposition of GaN is small, the ejection vector 14 is smaller than that shown in Fig. 10. Such preparatory irradiation can prevent the occurrence of the Fig. 10 shown gap sections 11c.

[0159] In the Fig. The example shown in Figure 11 is after the preparatory irradiation step described in Fig. 11(a), which is shown in Fig. 11(b) is performed. In the all-in-one transfer step, irradiation with the laser beam 20 is performed with an energy that can transfer GaN contained in the interface 11 in the same manner as in the all-in-one transfer step shown in Fig. 10 and can remove the objects 10 to be transferred from the first substrate 1. At this time, the same large ejection vector 14 acts as in Fig. 10, onto the portions 11a of the interface 11. Since the preparatory irradiation step causes a very thin delamination in advance in the portions 11b adjacent to the portions 11a of the interface 11, the effect of stresses that may cause the split portions 11c can be prevented. As a result, even after the objects 10 to be transferred have been removed from the first substrate 1, it is possible to prevent the residues, as shown in Fig. 8, as shown in Fig. 9 shown.

[0160] Although the residue 13 originates from a portion of the objects 10 to be transferred, in this embodiment, it is part of the components for holding the objects 10 to be transferred on the first substrate 1, and thus, the function of the objects 10 to be transferred is not significantly impaired. Therefore, even if the residue 13 remains on the first substrate 1 or the objects 10 to be transferred, this does not mean that the objects 10 to be transferred are damaged.

[0161] However, if the residue 13 remains after transfer, and if the objects to be transferred are light-emitting devices, there is a risk of uneven light emission or a source of dust. For mass production, it is advantageous to suppress the generation of the residue because it requires cleaning the first substrate 1 and the objects 10 to be transferred.

[0162] It should be noted that a description has been given of cleavages that may occur when a material with a crystal structure, such as a GaN layer, is used as the ablation layer.

[0163] On the other hand, the present invention is also effective for an ablation layer in which the occurrence of splitting is not a problem. In particular, when an organic film such as a polyimide film is used as an ablation layer, splitting occurs; however, by performing partial irradiation with a laser beam, the excessive propulsive force that occurs in objects 10 to be transferred during irradiation with a laser beam can be mitigated, and thus the transfer of the objects 10 to be transferred to the second substrate 2 can be controlled. Examples of such organic films include, in addition to polyimide films, organic films such as polymethyl methacrylate, polycarbonate, polyethylene terephthalate, nitrocellulose, polystyrene, poly(α-methylstyrene), and polytetrafluoroethylene.

[0164] When an organic film such as a polyimide film is used as an ablation layer, the laser energy density required to ablate the ablation layer is generally lower than the energy density required when an inorganic film such as a GaN layer is used as the ablation layer. In particular, the energy density required to ablate a GaN layer is approximately 1200 to 1600 mJ / cm 2 , while for removing a polyimide film the energy density is about 50 to 300 mJ / cm 2 Therefore, when the shape of the laser beam irradiated onto the photomask 6 is made rectangular or linear, the length in the longitudinal direction of the laser shape can be increased without changing the length in the short direction. In particular, when attempting to produce a rectangular or linear laser beam with an energy density of about 1200 to 1600 mJ / cm 2The upper limit of the longitudinal length is about 30 mm. However, if you try to obtain a rectangular or linear laser beam with an energy density of about 50 to 300 mJ / cm 2To obtain the desired length, the length in the longitudinal direction can be increased to about 90 mm. Therefore, by using a laser beam with such a long length in the longitudinal direction, it is possible to apply laser lift-off to a large number of objects 10 to be transferred at once. Even if the occurrence of transfer defects is small at first glance, in such a case where a large number of objects 10 to be transferred are transferred at once, a large number of transfer defects will occur due to the large number of objects 10 to be transferred. In other words, when transferring a large number of objects 10 to be transferred at once, it is very important to improve the transfer precision, and the industrial effects achieved by applying the present invention are very significant.

[0165] In the Fig. 7 and Fig. 11, the energy of the laser beam 20e incident on the portions 11b of the interface 11 in the preparatory irradiation step is set smaller than the energy of the laser beam 20 incident on the portions 11a of the interface 11 in the all-in-one transfer step by adjusting the energy of the laser beam 20d incident on the photomask 130 or the power of the laser beam 20e incident on the photomask 130. Fig. 1 shown laser oscillator 110 is changed. <Zweites Beispiel>

[0166] Fig. 12(a) schematically shows the second example of the preparatory irradiation step in an example of the laser lift-off method according to the invention. Fig. Figure 12(b) shows an example of the all-in-one transfer step performed after the Fig. 12(a) is carried out. Furthermore, Fig. 13 an enlarged view of part XIII of the Fig. 12 photomask used.

[0167] The second example differs from the first example in that the energy of the laser beam 20b incident on the photomask 130 does not differ between the preliminary irradiation step and the all-in-one transfer step; that is, the laser power of the laser oscillator 110 is not changed, and in the second pattern 32 of the photomask 130 used in the preliminary irradiation step.

[0168] The second pattern 32 of the photomask 130 in the second example has a plurality of openings 132c, as shown in Fig. 12(a) and Fig. 13, and dot-shaped non-opening portions 132d provided in each of the opening portions 132c.

[0169] Each of the point-shaped non-aperture portions 132d is smaller than the irradiation wavelength of the laser beam 20b incident on the photomask 130. Therefore, the non-aperture portions 132d do not contribute to changing the irradiation shape of the laser beam 20b. On the other hand, the laser beam 20b impinges on the non-aperture portions 132d, thus attenuating the energy of the laser beam 20b. Therefore, the laser beam 20b, by passing through the second pattern 32 with the non-opening portions 132d of the photomask 130, is formed into the laser beam 20f having a pattern corresponding to the opening portions 132c, which is the same pattern as when the non-opening portions 132d are not present, and its attenuated energy is attenuated, and the laser beam 20f is emitted from the photomask 130. Thus, in the Fig. 12(a), portions 11b of the interface 11 between each of the objects 10 to be transferred and the first substrate 1 are irradiated with the laser beam 20f having a lower energy than that of the laser beam 20 used in the preparatory irradiation step shown in Fig. 12(b) shown all at once, and which is not sufficient to remove the objects 10 to be transferred from the first substrate 1. <Drittes Beispiel>

[0170] Fig. 14(a) schematically shows the third example of the preparatory irradiation step in an example of the laser lift-off method according to the present invention. Fig. Figure 14(b) shows an example of the one-shot transfer step performed after the Fig. 14(a) is carried out. Furthermore, Fig. 15 an enlarged view of part XV of the Fig. 14 photomask used.

[0171] The third example differs from the second example in that each opening 132e in the second pattern 32 of the photomask 130 is provided with striped non-opening portions 132f.

[0172] The width of each of the striped non-opening portions 132f is smaller than the irradiation wavelength of the laser beam 20b incident on the photomask 130. Therefore, the non-opening portions 132f do not participate in changing the irradiation shape of the laser beam 20b. On the other hand, the laser beam 20b encounters the non-opening portions 132f, and thus the energy of the laser beam 20b is attenuated. Therefore, by passing through the second pattern 32 having the non-opening portions 132f of the photomask 130, the laser beam 20b is formed into a laser beam 20g having a pattern corresponding to the opening portions 132e, which is the same pattern as when the non-opening portions 132f are absent, and the attenuated energy of the laser beam 20g is emitted from the photomask 130. Thus, in the Fig. 14(a), portions 11b of the interface 11 between each of the objects 10 to be transferred and the first substrate 1 are irradiated with the laser beam 20g having a lower energy than that of the laser beam 20 used in the preparatory irradiation step shown in Fig. 14(b) shown all at once, and which is not sufficient to remove the objects 10 to be transferred from the first substrate 1. <Viertens Beispiel>

[0173] Fig. 16(a) schematically shows the fourth example of the preparatory irradiation step in an example of the laser lift-off method according to the invention. Furthermore, Fig. 16(b) is an example of the one-shot transfer step that follows the procedure described in Fig. 16(a) is carried out. Furthermore, Fig. 17 an enlarged view of part XVII of the Fig. 16 photomask used.

[0174] The fourth example differs from the second example in that the second pattern 32 of the photomask 130 includes a plurality of phase shift mask portions 132g.

[0175] A portion of the components of the laser beam 20b incident on the phase-shift mask portions 132g undergoes a 180° phase shift upon passing through a phase-shift film enclosed in the phase-shift mask portions 132g. The phase-shifted component is 180° out of phase with the component that has not passed through the phase-shift film, and thus they cancel each other out. This attenuates the energy of the laser beam 20b incident on the phase-shift mask portions 132. Therefore, by passing through the second pattern 32 with the phase-shift mask portions 132g of the photomask 130, the laser beam 20b is formed into a laser beam 20h having a pattern corresponding to the opening portions 132g and attenuated energy, and the laser beam 20b is emitted from the photomask 130. Thus, the data contained in the Fig. 16(a), portions 11b of the interface 11 between each of the objects 10 to be transferred and the first substrate 1 are irradiated with the laser beam 20h having a lower energy than that of the laser beam 20 used in the preparatory irradiation step shown in Fig. 16(b) shown all at once, and which is not sufficient to remove the objects 10 to be transferred from the first substrate 1.

[0176] In this way, for example, according to the second to fourth examples, in the preliminary irradiation step, portions 11b of the interface 11 between each of the objects 10 to be transferred and the first substrate 1 can be irradiated with the laser beam having a lower energy than that of the laser beam 20 emitted in the subsequent all-in-one transfer step, and which is insufficient to remove the objects 10 to be transferred from the first substrate 1, without changing the power of the laser beam emitted by the oscillator 110. From a mass production perspective, it is very advantageous that the preliminary irradiation step and the all-in-one transfer step can be performed without changing the power of the laser oscillator 110.

[0177] A specific example in which the preliminary irradiation step and the simultaneous transfer step of the second example described with reference to Fig. 12 and Fig. 13, is described with reference to Fig. 18 and Fig. 19 described.

[0178] Fig. 18 is a schematic diagram showing an arrangement example of the photomask 130 that enables the preliminary irradiation step and the simultaneous transfer step of the second example to be performed, and the objects 10 to be transferred. In Fig. 18, illustrations of components other than the photomask 130 and the objects 10 to be transferred are omitted.

[0179] The Fig. 18 includes a second portion 134 which is a Fig. 12(a), and a first portion 133 having a second pattern 32 shown in Fig. 12(b) has the first pattern 31 shown.

[0180] An arrow in Fig. 18 indicates a direction of movement of the objects 10 to be transferred. In this example, the photomask 130 and the objects 10 to be transferred are arranged such that the second pattern 32 of the photomask 130 passes over the objects 10 to be transferred before the first pattern 31 does.

[0181] In the second pattern 32, a chromium shielding film which is the pattern forming layer 132 in which the opening portions 132c and the dot-shaped non-opening portions 132d are formed, which are Fig. 12(a) and Fig. 13 are formed on a quartz glass which is a base material 131.

[0182] The point-shaped non-opening sections 132d shield 15% of the opening area of ​​each of the opening sections 132c.

[0183] In the first pattern 31, on the other hand, a chromium shielding film which is the pattern forming layer 132 in which the opening portions 132a are formed is formed, which are Fig. 12(b) are formed on a quartz glass which is a base material 131.

[0184] Therefore, the first portion 133 of the photomask 130 has a first laser transmittance and the second portion 134 has a second laser transmittance that is less than the first laser transmittance.

[0185] When the laser lift-off is carried out with such an arrangement, in particular, the energy (energy density) of the laser beam 20f incident on the portions 11b of the interface 11 between each of the objects 10 to be transferred and the first substrate 1 is in the Fig. 12(a) is 15% lower than the energy of the laser beam 20 incident on the portions 11a of the interface 11 between each of the objects 10 to be transferred and the first substrate 1, in which Fig. 12(b). For example, if the energy incident on the portions 11a of the interface 11 in the single transfer step is 1.4 J / cm 2 , the energy of the laser beam 20f incident on the sections 11b of the interface 11 in the preparatory irradiation step is 1.2 J / cm 2 .

[0186] If the preparatory irradiation step and the simultaneous transfer step are carried out in the Fig. 18 shown arrangement, for example as in Fig. 19, the second pattern 32 having the plurality of irradiated portions 32a in the preliminary irradiation step and the first pattern 31 having the plurality of irradiated portions 31a in the all-at-once transfer step are formed so as to be shifted from each other.

[0187] As an example, Fig. 18 a photomask 130 with the second pattern 32, which in Fig. 12 and Fig. 13, but the photomask 130 used in the present invention may have the second pattern 32 in the other example described above or other second patterns.

[0188] The preparatory irradiation step described above can be carried out in various forms.

[0189] For example, the preparatory irradiation step can be performed 1 to 4 times.

[0190] The number of times the preliminary irradiation step is not particularly limited, but performing the preliminary irradiation step once or twice can improve the speed of the laser lift-off transfer process. Furthermore, performing the preliminary irradiation step three or four times makes it easier to control the impact applied to the objects to be transferred during laser lift-off while maintaining an appropriate speed for the laser lift-off transfer process.

[0191] For example, in each of the preliminary irradiation step and the one-time transfer step, irradiation with the laser beam is carried out so that an irradiated area with the laser beam (for example, the irradiated portions 31a and 32a shown in Fig. 19) is 10 to 60% of an area of ​​the interface 11 between each of the objects 10 to be transferred and the first substrate 1.

[0192] When an irradiation area by the partial irradiation in each of the preliminary irradiation step and the all-at-once transfer step is within the range of 10 to 60% of the area of ​​the interface 11 between each of the objects 10 to be transferred and the first substrate 1, it is possible to efficiently transfer the objects to be transferred from the first substrate to the second substrate and provide a margin for irradiation errors of the laser beam.

[0193] Furthermore, the irradiation areas with the laser beam are preferably set to be different between the preparatory irradiation step and the all-in-one transfer step.

[0194] By changing the laser irradiated area between the preparatory irradiation step and the all-in-one transfer step, for example as described in relation to Fig. 11, it is possible to detect the occurrence of Fig. 10 when a material having a crystal structure, such as a GaN layer, is used as the ablation layer.

[0195] In addition, the preliminary irradiation step and the simultaneous transfer step are performed such that the irradiated areas do not overlap with each other, or such that an overlap of the irradiated areas is 10% or less of the area of ​​the interface 11 between each of the objects 10 to be transferred and the first substrate 1.

[0196] The irradiation areas in the preparatory irradiation step and the all-at-once transfer step can overlap with each other, and by making the overlap more than 0% and less than 10%, it is possible to provide a margin for irradiation errors of the laser beam.

[0197] For example, the degree to which the irradiation areas overlap with each other can be easily controlled by arranging the arrangement of the opening portions in the first portion 133 and the second portion 134 of the photomask 130 in the matrix.

[0198] Furthermore, it is preferable if the laser irradiated portion or non-irradiated portions have a line shape as shown in Fig. 4, Fig. 5(c) and (d), and Fig. 6(c) and (d) show that the laser-irradiated portion or non-irradiated portions are arranged at intervals equal to or greater than the width in the short-length directions of these portions. With such an arrangement, the degree of overlap of the irradiated portions can be easily controlled.

[0199] In addition, the irradiated areas as the total sum of the preparatory irradiation step and the transfer step at once may be 40 to 100% of an area of ​​the interface 11 between each of the objects 10 to be transferred and the first substrate 1.

[0200] By irradiating 40% or more of the area of ​​the interface 11 between each of the objects 10 to be transferred and the first substrate 1 with the laser beam as the sum of the preliminary irradiation step and the transfer step at once, the transfer of the objects can be performed more efficiently. As the sum of the preliminary irradiation step and the transfer step at once, the entire area or 100% of the interface 11 between each of the objects 10 to be transferred and the first substrate 1 can be irradiated with the laser beam.

[0201] It is particularly preferred that the laser lift-off device according to the invention is configured to be able to carry out the preparatory irradiation step described above.

[0202] For example, the laser lift-off device 100 according to the invention can be further configured to switch the energy of the laser beam for irradiating the interfaces 11 between the objects 10 to be transferred and the first substrate 1 between an energy that is not sufficient to remove the objects 10 to be transferred from the first substrate 1 and an energy that is sufficient to remove the objects 10 to be transferred from the first substrate 1, as described with reference to Fig. 7 described first example.

[0203] Alternatively, in the laser lift-off device 100, the pattern of the photomask may include the first pattern 31 and the second pattern 32, like the second to fourth examples described with reference to Fig. 12 to 17, and the laser lift-off device may be configured to: be able to irradiate the interfaces 11 between the objects 10 to be transferred and the first substrate 1 with the laser beam 20 through the first pattern 31 at once with an energy sufficient to remove the objects 10 to be transferred from the first substrate 1; and thus, to be able to irradiate the interfaces 11 between the objects 10 to be transferred and the first substrate 1 with the laser beam through the first pattern 32 at once with an energy insufficient to remove the objects 10 to be transferred from the first substrate 1. The laser lift-off device 100 having such aspects is very advantageous in terms of mass production. [Objects to be transferred]

[0204] The objects to be transferred in the present invention are not particularly limited. For example, objects selected from the group consisting of semiconductor chips, LED chips, resin material films, and inorganic films can be transferred. The resin material film may contain an inorganic material. Further, the resin material film may have a multilayer structure, and a plurality of films constituting the multilayer structure may be made of only one resin material film or may be made of a combination of a resin material film and an inorganic material film.

[0205] When thin objects to be transferred with a thickness of 1 to 10 µm are subjected to full-surface irradiation using a standard laser lift-off process, the longer a longitudinal dimension of the objects to be transferred or a portion of the objects to be transferred, the more likely the objects to be damaged during the laser lift-off. This is especially true for objects to be transferred with a longitudinal dimension of 80 µm or more or objects to be transferred with an area of ​​6400 µm. 2or more, the objects to be transferred are easily broken during laser lift-off by performing full-surface irradiation. Therefore, applying the present invention is effective, which can reduce the propulsive force exerted on the transferred objects. The upper limits for the longitudinal dimension and area are not particularly limited, but for ease of manufacture, they are approximately 500 µm or less and 40,000 µm, respectively. 2 or less. [Method for producing a receiver substrate]

[0206] The above-described laser lift-off method of the present invention can be applied, for example, to a method for manufacturing a receiver substrate.

[0207] For example, if it is a method for producing a receiver substrate provided with objects to be transferred, the method comprises: a step of providing a donor substrate provided with the objects to be transferred and a receiver precursor substrate; and a step of obtaining the receiver substrate by transferring the objects to be transferred from the donor substrate to the receiver precursor substrate due to laser lift-off, wherein in the step of obtaining the receiver substrate due to the laser lift-off method according to the invention, the objects to be transferred are subjected to laser lift-off from the donor substrate as the first substrate to the receiver precursor substrate as the second substrate;Since a receiving substrate is obtained by transferring objects to be transferred according to the laser lift-off method of the present invention, it is possible to produce a receiving substrate provided with the objects to be transferred without positional deviation thereof or damage.

[0208] The method of producing a receiver substrate according to the invention is an example of the application of the laser lift-off method according to the invention, and the application of the laser lift-off method according to the invention is not limited thereto. [Photomask]

[0209] The photomask according to the invention is a photomask that can be used in the laser lift-off method of the present invention described above. Therefore, the photomask according to the invention includes all of the above-described aspects of photomask 130.

[0210] For example, a photomask of the first aspect of the present invention is a photomask used in a laser lift-off method in which the objects 10 to be transferred are transferred from the first substrate 1 provided with the objects to be transferred to the second substrate 2 due to laser lift-off, the photomask being configured so that the interface 11 between each of the objects 10 to be transferred and the first substrate 1 is irradiated at once with a received laser beam, and the photomask has a pattern 31 for shaping the laser beam so that only a portion 11a of the interface 11 between each of the objects 10 to be transferred and the first substrate 1 is to be an irradiated portion.

[0211] As described above, the pattern 31 of the photomask 130 may shape the laser beam to form a plurality of laser irradiated portions, or may shape the laser beam to form a plurality of non-irradiated portions in which the laser beam is not irradiated at the interface 11 between each of the objects 10 to be transferred and the first substrate 1.

[0212] Furthermore, by using the photomask having a first part 133 with the pattern (a first pattern) 31 formed thereon and a first laser transmittance, and a second part 134 with a second laser transmittance lower than the first laser transmittance, the preliminary irradiation step and the all-at-once transfer step described above can be performed without changing the laser power of the laser oscillator 110.

[0213] Expressing such a photomask 130 from a further aspect, it can be said about the photomask of the present invention in a second aspect that the photomask 130 used in a laser lift-off method in which objects 10 to be transferred are transferred from a first substrate provided with the objects 10 to be transferred to a second substrate due to laser lift-off comprises: a first part 133 having a pattern 31 for shaping a shape of a received laser beam into a patterned shape and a first laser transmittance, and a second portion 134 having a second laser transmittance less than the first laser transmittance.

[0214] By performing the laser lift-off method according to the invention using the photomask 130 according to the invention, it is possible to prevent damage to the objects to be transferred without causing positional deviation of the objects to be transferred during transfer. Note that the laser lift-off method according to the invention can be performed without using the photomask 130 according to the invention. EXAMPLES

[0215] The present invention will be specifically described below with reference to examples and comparative examples. However, the present invention is not limited thereto. (Example 1)

[0216] A sapphire substrate containing 1.5 million LED chips as the objects to be transferred was prepared as the first substrate. The size of the LED chips was 40 µm × 60 µm.

[0217] Further, a quartz substrate having a silicone rubber layer as an adhesive layer on its surface was provided as the second substrate.

[0218] In Example 1, a total of 1.5 million LED chips were fabricated using the contact LLO process using the Fig. 2 from the first substrate to the second substrate.

[0219] In Example 1, a preliminary irradiation step and a one-shot transfer step were performed using the photomask 130 as described with reference to Fig. 12, Fig. 13 and Fig. 18 described.

[0220] In particular, in this example, as in Fig. As shown in Figure 18, the objects to be transferred are moved relative to the photomask in the direction of the arrow. Therefore, in practice, laser lift-off is performed in the following sequence. (i) The preparatory irradiation step for a lower row (ii) The simultaneous transfer step for the lower row and the preparatory irradiation step for an upper row (iii) The simultaneous transfer step for the upper row and the preparatory irradiation step for a next row above the upper row (iv) The single transfer step for the next row above the upper row and the preparatory irradiation step for two rows above the upper row

[0221] Of course, the preliminary irradiation step and the all-in-one transfer step may be completed for each specific area; for example, the preliminary irradiation step and the all-in-one transfer step may be completed for each row, and then the preliminary irradiation step and the all-in-one transfer step may be performed for another area.

[0222] Furthermore, the simultaneous transfer step for all LED chips can be performed after the preliminary irradiation step has been performed on all LED chips. The preliminary irradiation step can be performed for all LED chips in a single step, or the preliminary irradiation steps can be performed separately for each of the divided specific areas. Furthermore, the simultaneous transfer step for all LED chips can be performed in a single step, or the simultaneous transfer step can be performed separately for each of the divided specific areas.

[0223] The first pattern 31 and the second pattern 32 of the photomask 130 were manufactured with a line to area ratio of 1:1, each with 8 µm.

[0224] In the preparatory irradiation step, the energy (energy density) of the laser beam 20f incident on the portions 11b of the interface 11 between each of the objects 10 to be transferred and the first substrate 1 was set to 1.2 J / cm 2 set.

[0225] The photomask 130 was then cut by 8 µm into the Fig. 18 and then the all-in-one transfer step was performed.

[0226] In the all-in-one transfer step, the energy (energy density) of the laser beam 20 incident on portions 11b of the interface 11 between each of the objects 10 to be transferred and the first substrate 1 was set to 1.4 J / cm 2 set. (Example 2)

[0227] In Example 2, a total of 1.5 million LED chips were transferred from a first substrate to a second substrate in the same manner as in Example 1, except that the preparatory irradiation step was not performed. (Comparison example)

[0228] In a comparative example, a total of 1.5 million LED chips were transferred from a first substrate to a second substrate in the same manner as in Example 2, except that the entire surface of the interfaces 11 between each of the objects 10 to be transferred and the first substrate 1 was irradiated with the laser beam in the all-at-once transfer step.

[0229] The LED chips transferred to the second substrate in Examples 1 and 2 were checked, and the results showed that the positioning accuracy of the LED chips was high and no major damage to the LED chips was confirmed.

[0230] On the other hand, in the comparative example, it was confirmed that 10% of the LED chips transferred to the second substrate were damaged.

[0231] A photograph of the first substrate after transfer in Example 1 is shown in Fig. 20. As shown in Fig. As can be seen from Figure 20, almost no residues were observed on the first substrate after transfer in Example 1.

[0232] On the other hand, Fig. 9 a photograph of the first substrate after transfer in Example 2. As can be seen from Fig. As can be seen from Figure 9, some residues were observed on the first substrate after transfer in Example 2.

[0233] It should be noted that the residue was observed as a black residue in the microscope due to the light used in this evaluation.

[0234] Note that in the above-described embodiment, an example was described in which LED chips having a GaN layer as objects to be transferred are subjected to lift-off from a sapphire substrate as the first substrate. However, the present invention is not limited to this embodiment. Specifically, it is also applicable to a case in which a resin material film or an inorganic film in a chip shape, or the like, a microscopic device, or a chip provided on a first substrate having a sapphire substrate or a glass substrate as the base material is transferred to a second substrate. Furthermore, it is also applicable to a case in which objects to be transferred, adhered via an ablation layer, are transferred from a first substrate having the ablation layer, such as a polyimide film, formed on its surface, to a second substrate.

[0235] Furthermore, the present invention is not limited to the embodiments described above. The above embodiments are merely examples, and any examples having substantially the same features and exhibiting the same functions and effects as those in the technical concept disclosed in the claims of the present invention are included within the technical scope of the present invention. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2020-4478 A

[0014]

Claims

[1] A laser lift-off method for transferring objects to be transferred from a first substrate provided with the objects to be transferred to a second substrate by means of laser lift-off, comprising a one-time transfer step in which objects to be transferred are removed from a first substrate by simultaneously irradiating the interfaces between the objects to be transferred and the first substrate with a laser beam and are transferred all at once to a second substrate, wherein in the transfer step which takes place at a time, only a portion of an interface between each of the objects to be transferred and the first substrate is irradiated with the laser beam. [2] The laser lift-off method according to claim 1, further comprising, prior to the all-in-one transfer step, a preparatory irradiation step of irradiating the interface between each of the objects to be transferred and the first substrate with a laser beam having a lower energy than that in the all-in-one transfer step and insufficient to remove the objects to be transferred from the first substrate. [3] The laser lift-off method according to claim 2, wherein in the preliminary irradiation step, only a portion of the interface between each of the objects to be transferred and the first substrate is irradiated with the laser beam. [4] The laser lift-off method according to claim 2 or 3, wherein the preparatory irradiation step is performed 1 to 4 times. [5] The laser lift-off method according to any one of claims 2 to 4, wherein in each of the preliminary irradiation step and the all-at-once transferring step, irradiation with the laser beam is performed such that an irradiated area with the laser beam is 10 to 60% of an area of ​​the interface between each of the objects to be transferred and the first substrate. [6] The laser lift-off method according to any one of claims 2 to 5, wherein the irradiated areas with the laser beam are set to be different between the preliminary irradiation step and the all-in-one transfer step. [7] The laser lift-off method according to claim 6, wherein the preliminary irradiation step and the all-at-once transferring step are performed so that there is no overlap of the irradiated areas with the laser beam, or so that an overlapping area of ​​the irradiated areas with the laser beam is 10% or less of the area of ​​the interface between each of the objects to be transferred and the first substrate. [8] The laser lift-off method according to claim 6 or 7, wherein, as a total of the preliminary irradiation step and the all-at-once transfer step, 40 to 100% of an area of ​​the interface between each of the objects to be transferred and the first substrate is irradiated with the laser beam. [9] A laser lift-off method according to any one of claims 2 to 8, wherein laser powers are adjusted to differ between the preparatory irradiation step and the all-in-one transfer step. [10] Laser lift-off method according to one of claims 2 to 8, wherein a photomask is provided having a first part with a first laser transmittance and a second part with a second laser transmittance which is less than the first laser transmittance, in the preparatory irradiation step, irradiation with the laser beam takes place through the second part of the photomask, and In the transfer step, which takes place all at once, the laser beam is irradiated through the first part of the photomask. [11] The laser lift-off method according to claim 1, wherein in the all-at-once transferring step, irradiation with the laser beam is performed such that an irradiated area with the laser beam is 40 to 90% of an area of ​​the interface between each of the objects to be transferred and the first substrate. [12] The laser lift-off method according to any one of claims 1 to 11, wherein, in the all-at-once transferring step, irradiation with the laser beam is carried out so that laser-irradiated portions are formed in multiples at the interface between each of the objects to be transferred and the first substrate. [13] The laser lift-off method according to claim 12, wherein in the all-at-once transferring step, the irradiation of the laser beam is performed such that the laser-irradiated portions have at least one shape selected from the group consisting of a circular shape, an elliptical shape and a polygonal shape. [14] The laser-laser lift-off method according to claim 12, wherein in the all-at-once transferring step, the irradiation of the laser beam is carried out such that the laser-irradiated portions have a line shape. [15] The laser lift-off method according to claim 12, wherein in the all-at-once transferring step, the laser irradiated portions have a rectangular shape or a line shape, and the irradiation of the laser beam is performed such that a longitudinal direction of the laser irradiated portions approximately coincides with the longitudinal direction of the objects to be transferred. [16] The laser lift-off method according to claim 12, wherein in the all-at-once transferring step, the laser irradiated portions have a rectangular shape or a line shape, and the irradiation of the laser beam is performed such that a longitudinal direction of the laser irradiated portions approximately coincides with a short length direction of the objects to be transferred. [17] The laser lift-off method according to claim 12, wherein in the all-at-once transferring step, the laser irradiated portions have a rectangular shape or a line shape, and the irradiation of the laser beam can be carried out so that the laser irradiated portions come to lie on adjacent objects to be transferred. [18] The laser lift-off method according to any one of claims 1 to 11, wherein in the all-at-once transferring step, irradiation of the laser beam is performed so that non-irradiated portions at which irradiation of the laser beam is not performed are plurally formed at the interface between each of the objects to be transferred and the first substrate. [19] The laser lift-off method according to claim 18, wherein in the all-at-once transferring step, the irradiation of the laser beam is performed such that the non-irradiated portions have at least one shape selected from the group consisting of a circular shape, an elliptical shape and a polygonal shape. [20] The laser-laser lift-off method according to claim 18, wherein in the all-at-once transferring step, the irradiation with the laser beam is carried out so that the non-irradiated portions have a line shape. [21] The laser lift-off method according to claim 18, wherein in the all-at-once transferring step, the non-irradiated portions have a rectangular shape or a line shape, and the irradiation with the laser beam is performed such that a longitudinal direction of the non-irradiated portions approximately coincides with a longitudinal direction of the objects to be transferred. [22] The laser lift-off method according to claim 18, wherein in the all-at-once transferring step, the non-irradiated portions have a rectangular shape or a line shape, and the irradiation of the laser beam is performed such that a longitudinal direction of the non-irradiated portions approximately coincides with a short length direction of the objects to be transferred. [23] The laser lift-off method according to claim 18, wherein in the all-at-once transferring step, the non-irradiated portions have a rectangular shape or a line shape, and the irradiation with the laser beam can be carried out so that the non-irradiated portions come to lie on adjacent objects to be transferred. [24] The laser lift-off method according to any one of claims 1 to 23, wherein the objects to be transferred are selected from the group consisting of semiconductor chips, LED chips, resin material films and inorganic films. [25] A method for producing a receiving substrate provided with objects to be transferred, the method comprising: a step of providing a donor substrate provided with the objects to be transferred and a receiver precursor substrate; and a step of obtaining a receiver substrate by transferring the objects to be transferred from the donor substrate to the receiver precursor substrate due to the laser lift-off, wherein in the step of obtaining the receiver substrate due to the laser lift-off method according to any one of claims 1 to 23, the objects to be transferred are subjected to a laser lift-off from the donor substrate as the first substrate to the receiver precursor substrate as the second substrate. [26] Laser lift-off device for transferring objects to be transferred from a first substrate provided with the objects to be transferred to a second substrate due to laser lift-off, the device comprising: a laser oscillator; a table for supporting the first substrate and the second substrate while facing each other; and a photomask provided in an optical path between the laser oscillator and the table, wherein the laser oscillator, the photomask and the table are configured to irradiate interfaces between the objects to be transferred and the first substrate at once with a laser beam from the laser oscillator, and the photomask has a pattern for shaping a laser beam from the laser oscillator into such a shape that only a portion of an interface between each of the objects to be transferred and the first substrate is irradiated with the laser beam. [27] The laser lift-off device according to claim 26, wherein the laser lift-off device is further configured to switch energy of the laser beam for irradiating the interfaces between the objects to be transferred and the first substrate with the laser beam between an energy insufficient to remove the objects to be transferred from the first substrate and an energy sufficient to remove the objects to be transferred from the first substrate. [28] The laser lift-off device according to claim 27, wherein the pattern of the photomask includes a first pattern and a second pattern, and the laser lift-off device is configured: in order to be able to irradiate interfaces between the objects to be transferred and the first substrate with the laser beam through the first pattern at once with the energy sufficient to remove the objects to be transferred from the first substrate, and in order to be able to irradiate interfaces between the objects to be transferred from the first substrate with the laser beam through the second pattern at once with an energy that is not sufficient to remove the objects to be transferred from the first substrate. [29] A photomask used in a laser lift-off process in which objects to be transferred are transferred from a first substrate provided with the objects to be transferred to a second substrate due to laser lift-off, wherein the photomask is configured so that an interface between each of the objects to be transferred and the first substrate is irradiated with a received laser beam at once, and the photomask has a pattern to shape the laser beam such that only a portion of the interface between each of the objects to be transferred and the first substrate is to be an irradiated portion. [30] The photomask according to claim 29, wherein the pattern is a pattern for shaping the laser beam so that the laser irradiated portions are formed in multiples. [31] The photomask according to claim 29, wherein the pattern is a pattern for shaping the laser beam so that non-irradiated portions at which irradiation with the laser beam is not performed are plurally formed at the interface between each of the objects to be transferred and the first substrate. [32] A photomask according to any one of claims 29 to 31, wherein the photomask comprises: a first part on which the pattern is formed and which has a first laser transmittance; and a second part having a second laser transmittance that is less than the first laser transmittance. [33] A photomask used in a laser lift-off process in which objects to be transferred are transferred from a first substrate provided with the objects to be transferred to a second substrate due to laser lift-off, comprising: a first part having a pattern configured to shape a received laser beam into a patterned shape and a first laser transmittance; and a second part having a second laser transmittance that is less than the first laser transmittance.

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