Laser processing device and laser processing method

Abstract

The present specification relates to a device (20) configured for laser processing, the device comprising a laser-transparent substrate (22) and an object (30) bonded to the substrate via a photonic crystal (40).

Description

Technical Field

[0001] The present disclosure generally relates to a laser processing device and a laser processing method for such a device.

Background Art

[0002] In certain applications, it may be desirable to perform laser processing of an object present on a support through which a laser substantially passes. An application example is the separation of an object bonded to a support, such as an electronic circuit. For this purpose, a layer that absorbs the laser is disposed between the object to be separated and the support, the focus of the laser beam is adjusted to this absorption layer, and the object is separated from the support by ablation of the absorption layer. The absorption layer corresponds to, for example, a metal layer, particularly a gold layer.

Summary of the Invention

Problems to be Solved by the Invention

[0003] When the object is an electronic circuit, it may be desirable for the support to correspond to the substrate on which the electronic circuit is formed in order to avoid transfer of the electronic circuit to the support. In this case, the absorption layer corresponds to a layer formed monolithically with the layer of the electronic circuit.

[0004] A disadvantage may be that it is difficult to form an absorption layer having desired absorption characteristics. This can be the case especially when the object is at least partially formed by epitaxially depositing a layer on the absorption layer. In fact, it is generally impossible to use a metal absorption layer. Therefore, it is necessary to increase the output of the laser used to remove the absorption layer. In this case, it may be difficult to prevent deterioration of the region near the absorption layer, particularly the region forming a part of the object to be separated. This can further be the case when the thickness of the absorption layer is limited, especially for cost reasons or technical feasibility reasons.

[0005] Accordingly, an object of the embodiments is to at least partially overcome the disadvantages of the laser processing device described above and the laser processing method using such a device.

[0006] An object of the embodiments is to align the focus of the laser beam with the area to be processed of the device through a part of the device.

[0007] Another object of the embodiments is that the area close to the area to be processed is not damaged by the processing.

[0008] Another object of the embodiments is that the method of manufacturing the device does not have a step of moving one element to another element.

[0009] Another object of the embodiments is that the method of manufacturing the device has an epitaxial deposition step.

[0010] Another object of the embodiments is to reduce the thickness of the absorption layer.

Means for Solving the Problems

[0011] The embodiments provide a device configured to be processed by a laser, the device comprising a substrate through which the laser passes and an object respectively joined to the substrate via a photonic crystal.

[0012] According to the embodiments, the photonic crystal is a two-dimensional photonic crystal.

[0013] According to the embodiments, the photonic crystal has a base layer of a first material and columnar bodies arranged in a lattice pattern of a second material different from the first material, and the columnar bodies respectively extend to the base layer over at least a part of the thickness of the base layer.

[0014] According to the embodiments, the first material has an absorption coefficient of less than 1 with respect to the laser.

[0015] According to an embodiment, the second material has an absorption coefficient of less than 1 with respect to the laser.

[0016] According to an embodiment, the substrate is formed of the second material.

[0017] According to an embodiment, the second material has an absorption coefficient in the range of 1 to 10 with respect to the laser.

[0018] According to an embodiment, the substrate has a first surface and a second surface facing each other, the laser is configured to cross the substrate from the first surface to the second surface, and the photonic crystal covers the second surface.

[0019] According to an embodiment, the device further includes a layer that absorbs the laser between the object and the substrate.

[0020] According to an embodiment, the device further includes at least one layer that is disposed between the photonic crystal and the layer that absorbs the laser and that passes the laser.

[0021] According to an embodiment, the substrate is a semiconductor.

[0022] According to an embodiment, the substrate is formed of at least two mixtures or alloys of silicon, germanium, or compounds thereof.

[0023] According to an embodiment, the object has an electronic circuit.

[0024] According to an embodiment, the object has at least one optoelectronic component having a three-dimensional semiconductor element covered with an active layer, and the three-dimensional semiconductor element has a base in contact with at least one of the columns.

[0025] According to an embodiment, the second material is a nitride, carbide, or boride of a transition metal in Group IV, V, or VI of the periodic table of elements, or a combination of these compounds, or aluminum nitride, aluminum oxide, boron, boron nitride, titanium, titanium nitride, tantalum, tantalum nitride, hafnium, hafnium nitride, niobium, niobium nitride, zirconium, zirconium boride, zirconium nitride, silicon carbide, tantalum carbonitride, magnesium nitride, or a mixture of at least two of these compounds.

[0026] An embodiment further provides a method for manufacturing a device including a substrate through which a laser passes and an object respectively joined to the substrate via a photonic crystal, the method including forming the photonic crystal and forming the object.

[0027] According to an embodiment, in the method, the object is formed on the photonic crystal by forming the photonic crystal on the substrate and depositing and / or growing a layer on the photonic crystal.

[0028] An embodiment further provides a method for processing a device including a substrate through which a laser passes and an object respectively joined to the substrate via a photonic crystal with a laser, the method including exposing the photonic crystal to a laser beam through the substrate.

[0029] According to an embodiment, in the method, the object is joined to a support, the object remains connected to the substrate, and a region including the photonic crystal or a region adjacent to the photonic crystal is destroyed by a laser.

Brief Description of the Drawings

[0030] The foregoing and other features and advantages are described in detail in the remainder of the present disclosure of specific embodiments given as non-limiting examples with reference to the accompanying drawings.

[0031]

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Embodiments for Carrying Out the Invention

[0032] Like features are indicated by like reference numerals in the various figures. In particular, structural and / or functional features common to the various embodiments may have the same reference numeral and may have the same structural properties, dimensional properties, and material properties. For clarity, only the steps and elements useful for understanding the embodiments described herein are shown and described in detail. In particular, laser light sources are well known to those skilled in the art and are not described in detail below.

[0033] In the remainder of the present disclosure, when referring to terms that limit absolute positions such as "front", "rear", "top", "bottom", "left", "right", etc., or relative positions such as "above", "below", "upper side", "lower side", etc., this term refers to the orientation of the drawing, unless otherwise specified. Expressions such as "about", "substantially", "essentially", and "degree" represent within a range of 10% of the corresponding value, preferably within a range of 5%, unless otherwise specified. Further, in this specification, the terms "insulating" and "conductive" are considered to represent "electrically insulating" and "electrically conductive", respectively.

[0034] In the remainder of the present disclosure, the internal transmittance of a layer corresponds to the ratio of the intensity of the emitted radiation light from the layer to the intensity of the incident radiation light on the layer, and the rays of the incident radiation light are perpendicular to the layer. The absorptivity of a layer is equal to the difference between 1 and the internal transmittance. In the remainder of the present disclosure, when the absorptivity of the radiation light passing through a layer or a film is less than 60%, the layer or the film is considered to transmit the radiation light. In the remainder of the present disclosure, when the absorptivity of the radiation light passing through a layer or a film exceeds 60%, the layer or the film is considered to absorb the radiation light. In the remainder of the present disclosure, the laser is considered to correspond to monochromatic radiation light. In fact, the laser may have a narrow wavelength region centered on the central wavelength, referred to as the wavelength of the laser. In the remainder of the present disclosure, the refractive index of a material corresponds to the refractive index of the material at the wavelength of the laser used for laser processing. The imaginary part of the optical index of the corresponding material is referred to as the absorption coefficient k. The absorption coefficient is related to the linear absorption α of the material according to the relationship α = 4πk / λ.

[0035] FIG. 1 is a partial cross-sectional schematic view showing an embodiment of the processing system 10 of the device 20.

[0036] The processing system 10 includes a laser light source 12 and an optical focus adjustment device 14 having an optical axis D. The laser light source 12 is adapted to provide an incident laser beam 16 to the focus adjustment device 14, and the focus adjustment device provides a converging laser beam 18. The optical focus adjustment device 14 may have one optical component, two optical components, or three or more optical components, and the optical components correspond to, for example, lenses. The incident laser beam 16 is preferably substantially collimated along the optical axis D of the optical device 14.

[0037] The device 20 includes a substrate 22 having two opposing surfaces 24, 26. The laser beam 18 enters the substrate 22 through the surface 24. According to an embodiment, the surfaces 24 and 26 are parallel. According to an embodiment, the surfaces 24 and 26 are flat. According to an embodiment, the thickness of the substrate 22 is in the range of 50 μm to 3 mm. According to an embodiment, an anti-reflection layer of a laser (not shown) is provided on the surface 24 of the substrate 22. The substrate 22 may have a single-layer structure or a multi-layer structure. According to an embodiment, the substrate 22 is formed of a semiconductor material. The semiconductor material may be at least a mixture of two of silicon, germanium, or a compound thereof. The substrate 22 is preferably formed of silicon, more preferably single-crystalline silicon. According to another embodiment, the substrate 22 is at least partially formed of a non-semiconductor material, such as an insulating material, particularly sapphire, or a conductive material.

[0038] Device 20 includes an absorption region 28 on a surface 26 and at least one object 30 in contact with the absorption region 28. The object 30 is joined to the absorption region 28 on a side of the absorption region 28 opposite to the substrate 22 and is desirably separated from the substrate 22. As an example, FIG. 1 shows a plurality of objects 30 joined to the absorption region 28. The object 30 may have an electronic circuit, such as a circuit including a light-emitting diode, or a circuit including a transistor, particularly a MOS transistor. FIG. 1 shows an absorption region 28 that is continuous on the surface 26. As a variant, the absorption region 28 may exist only between each object 30 and the substrate 22 and may not exist between the objects 30.

[0039] In the processing method, the processing system 10 and the device 20 may be relatively moved so that the laser beam 18 irradiates the entire absorption region 28 to be processed. During processing, it is preferable that the optical axis D of the optical device 14 is perpendicular to the surface 24.

[0040] The wavelength of the laser is selected according to the material forming the substrate 22 so that the substrate 22 allows the laser to pass through.

[0041] According to an embodiment, particularly when the substrate 22 is a semiconductor, the wavelength of the laser beam 18 is preferably at least 500 nm, more preferably at least 700 nm greater than the wavelength corresponding to the bandgap of the material forming the substrate 22. For this reason, it is advantageous that the interaction between the laser beam 18 and the substrate 22 can be reduced while the laser beam 18 traverses the substrate 22. According to an embodiment, the wavelength of the laser beam 18 is smaller than the sum of 2,500 nm and the wavelength corresponding to the bandgap of the material forming the substrate 22. For this reason, it is advantageous that a laser beam forming a laser spot with a small size can be supplied more easily.

[0042] When the substrate 22 is a semiconductor, the wavelength of the laser beam 18 may be in the range of 200 nm to 10 μm. In particular, when the substrate 22 is formed of silicon having a bandgap of 1.14 eV corresponding to a wavelength of 1.1 μm, the wavelength of the laser beam 18 is selected to be approximately equal to 2 μm. When the substrate 22 is formed of germanium having a bandgap of 0.661 eV corresponding to a wavelength of 1.87 μm, the wavelength of the laser beam 18 is selected to be approximately equal to 2 μm or 2.35 μm.

[0043] When the substrate 22 is formed of sapphire, the wavelength of the laser beam 18 may be in the range of 300 nm to 5 μm.

[0044] According to an embodiment, the laser beam 18 is polarized. According to an embodiment, the laser beam 18 is polarized according to linear polarization. For this reason, it is advantageous that the interaction between the laser beam 18 and the absorption region 28 can be enhanced. According to another embodiment, the laser beam 18 is polarized according to circular polarization. For this reason, it is advantageous that the propagation of the laser beam 18 to the substrate 22 can be promoted.

[0045] According to an embodiment, the laser beam 18 is emitted by the processing system 10 in the form of one pulse, two pulses, or three or more pulses, and the duration of each pulse is in the range of 0.1 ps to 1,000 ns. The peak output of the laser beam per pulse is in the range of 10 kW to 100 MW.

[0046] FIG. 2 is an enlarged view showing an embodiment of the absorption region 28 of the device 20. According to this embodiment, the absorption region 28 corresponds to a laminate of a photonic crystal layer 40 and an absorption layer 42 that absorbs the laser. According to an embodiment, the photonic crystal layer 40 is disposed between the surface 26 of the substrate 22 and the absorption layer 42. As a modification, the absorption layer 42 is disposed between the surface 26 of the substrate 22 and the photonic crystal layer 40. According to an embodiment, the propagation mode of the photonic crystal layer 40 corresponds to the wavelength of the laser. The photonic crystal layer 40 preferably corresponds to a two-dimensional photonic crystal.

[0047] According to an embodiment, the thickness of the absorption layer 42 is in the range of 5 nm to 80 nm. The absorption rate of the absorption layer 42 with respect to the laser exceeds 80%. According to an embodiment, the absorption layer 42 is formed of at least a mixture of two of a metal nitride, a semiconductor material, or a compound thereof. According to an embodiment, the absorption coefficient k of the absorption layer 42 in a linear state with respect to the wavelength of the laser is in the range of 1 to 10.

[0048] The photonic crystal layer 40 has a layer 44, hereinafter referred to as a base layer, of a first material having a first refractive index at the wavelength of the laser, and columnar bodies 46 of a second material having a second refractive index at the wavelength of the laser extend on the base layer. According to an embodiment, each columnar body 46 extends substantially along a central axis perpendicular to the surface 26 along a height L measured perpendicular to the surface 26. The distance between the central axes of two adjacent columnar bodies is referred to as "a" (pitch). According to an embodiment, each columnar body 46 extends substantially over the entire thickness of the base layer 44. It is preferable that the first refractive index is smaller than the second refractive index. The first material may have an absorption coefficient of less than 1 at the wavelength of the laser 18. The first material may be a nitride or an oxide of a semiconductor compound, for example, silicon oxide (SiO 2 )), silicon nitride (SiN), or aluminum oxide (Al 2 O 3 ). The second material may have an absorption coefficient of less than 1 at the wavelength of the laser. The second material may be a nitride of a semiconductor compound such as GaN, or a semiconductor compound such as silicon (Si) or germanium (Ge). The thickness of the photonic crystal layer 40 may be in the range of 0.1 μm to 3 μm.

[0049] FIG. 3 is an enlarged view showing another embodiment of the absorption region 28 of the device 20. The absorption region 28 has all the elements described above with respect to the embodiment shown in FIG. 1, except that the absorption layer 42 is not provided. The columnar bodies 46 of the photonic crystal layer 40 may be formed of one of the materials described above with respect to the absorption layer 42. In this case, the columnar bodies 46 further perform the function of the absorption layer 42 as described in more detail below. As a variant, the base layer 44 of the photonic crystal layer 40 is formed of one of the materials described above with respect to the absorption layer 42. In this case, the base layer 44 further performs the function of the absorption layer 42 as described in more detail below.

[0050] FIG. 4 is an enlarged view showing another embodiment of the absorption region 28 of the device 20. The absorption region 28 has all the elements described above with respect to the embodiment shown in FIG. 1, except that it further includes at least one intermediate layer 48 disposed between the photonic crystal layer 40 and the absorption layer 42. The intermediate layer 48 is laser-passing. According to an embodiment, the intermediate layer 48 is formed of a semiconductor material, such as silicon (Si), an oxide of a semiconductor, such as silicon oxide (SiO 2 ), or a nitride of a semiconductor, such as silicon nitride (SiN). According to an embodiment, the thickness of the intermediate layer 48 is in the range of 1 nm to 500 nm, preferably in the range of 5 nm to 500 nm. As a variant, a laminate of two layers or three or more layers may be disposed between the photonic crystal layer 40 and the absorption layer 42. In this case, each layer of the laminate is laser-passing. According to an embodiment, the total thickness of the laminate is in the range of 1 nm to 500 nm, preferably in the range of 5 nm to 500 nm.

[0051] According to another embodiment of the absorption region 28, neither the absorption layer 42 is provided, nor the material forming the columnar bodies 46 of the photonic crystal layer 40 and the material forming the base layer 44 of the photonic crystal layer 40 have an absorption coefficient k in the range of 1 to 10 at the wavelength of the laser in the linear mode.

[0052] In the above-described embodiment of the absorption region 28, the height L of each columnar body 46 may be in the range of 0.1 μm to 3 μm. The columnar bodies 46 are preferably arranged in a lattice pattern. According to the embodiment, the pitch a between each columnar body 46 and one or more adjacent columnar bodies is substantially constant.

[0053] FIG. 5 is a partial enlarged plan schematic view of an embodiment of the photonic crystal layer 40 in which the columnar bodies 46 are arranged in a hexagonal lattice pattern. This means that the columnar bodies 46 are arranged in rows in a plan view, the centers of the columnar bodies 46 are at the vertices of an equilateral triangle, the centers of two adjacent columnar bodies 46 in the same row are separated by a pitch a, and the centers of the columnar bodies 46 in two adjacent rows are offset by a distance a / 2 along the row direction.

[0054] FIG. 6 is a partial enlarged plan schematic view of an embodiment of the photonic crystal layer 40 in which the columnar bodies 46 are arranged in a hexagonal lattice pattern. This means that the columnar bodies 46 are arranged in rows and columns, the centers of the columnar bodies 46 are at the vertices of a square, two adjacent columnar bodies 46 in the same row are separated by a pitch a, and two adjacent columnar bodies 46 in the same column are separated by a pitch a.

[0055] In the embodiments shown in FIGS. 5 and 6, each columnar body 46 has a circular cross-section with a diameter D in a plane parallel to the surface 26. In the case of a hexagonal lattice arrangement or a square lattice arrangement, the diameter D may be in the range of 0.05 μm to 2 μm. The pitch a may be in the range of 0.1 μm to 4 μm.

[0056] In the embodiments shown in FIGS. 5 and 6, the cross-section of each columnar body 46 in a plane parallel to the surface 26 is circular. However, the cross-section of the columnar body 46 may have different shapes, such as an oval, a polygon, particularly a square, a rectangle, a hexagon, etc. According to the embodiment, all the columnar bodies 46 have the same cross-section.

[0057] FIG. 7 is an enlarged cross-sectional view showing another embodiment of the device 20, and FIG. 8 is a plan view of a cross-section taken along line VIII-VIII of FIG. 7. The device 20 shown in FIG. 7 includes all the elements of the device 20 shown in FIG. 3. Further, in this embodiment, each object 30 corresponds to an optoelectronic circuit having at least one three-dimensional optoelectronic component 50, and one three-dimensional optoelectronic component 50 is shown in FIG. 7. The three-dimensional optoelectronic component 50 has wires, and other elements of the three-dimensional optoelectronic component 50 are not shown in FIG. 7 and will be described in more detail below. The base 53 of each wire 52 is placed on at least one, preferably a plurality of, the columns 46.

[0058] The device 20 further includes a seed structure 54 that covers the substrate 22 to advantageously facilitate the growth of the wires 52. The seed structure 54 has specific pads 46 of the photonic crystal layer 40 and may have an additional seed layer or a stack of additional layers. The seed structure 54 shown as an example in FIG. 7 particularly has a seed layer 56, and the seed layer 56 is disposed between the substrate 22 and the photonic crystal layer 40.

[0059] According to an embodiment, the base layer 44 of the photonic crystal layer 40 is formed of one of the materials described above with respect to the absorption layer 42. In this embodiment, the absorption of the laser is performed at the level of the photonic crystal layer 40 by a mechanism described in more detail below.

[0060] A more detailed embodiment of the optoelectronic component 50 when the optoelectronic component 50 of the object 30 corresponds to a three-dimensional type light emitting diode is described in connection with FIGS. 9 and 10. However, it should be clear that these embodiments may also relate to other applications, particularly optoelectronic components for the detection or measurement of electromagnetic radiation, or optoelectronic components for photovoltaic applications.

[0061] FIG. 9 is a partial cross-sectional schematic view showing an embodiment of the optoelectronic component 50 of the optoelectronic circuit 30. The optoelectronic circuit 30 further has an insulating layer 58 that covers the photonic crystal layer 40.

[0062] The three-dimensional optoelectronic component 50 has a wire 52 protruding from the photonic crystal layer 40, which is schematically shown in FIGS. 9 and 10. The optoelectronic component 50 further has a shell 60 covering the outer wall of the upper portion of the wire 52, and the shell 60 has at least one laminate of an active layer 62 covering the upper portion of the wire 52 and a semiconductor layer 64 covering the active layer 62. In this embodiment, since the shell 60 covers the side wall of the wire 52, the optoelectronic component 50 is called a radial configuration. The optoelectronic circuit 30 further has an insulating layer 66 extending on the insulating layer 58 and extending on the side wall of the lower portion of the shell 60. The optoelectronic circuit 30 further has a conductive layer 68 covering the shell 60 to form an electrode, and the conductive layer 68 passes the emitted light emitted by the active layer 62. The conductive layer 68 may particularly cover the shells 60 of a plurality of optoelectronic components 50 of the optoelectronic circuit 30, and thus form an electrode common to the plurality of optoelectronic components 50. The optoelectronic circuit 30 further has a conductive layer 70 extending on the electrode layer 68 between the wires 52. The optoelectronic circuit 30 further has a sealing layer 72 covering the optoelectronic component 50.

[0063] FIG. 10 is a partial cross-sectional schematic view of another embodiment of the optoelectronic component 50. The optoelectronic component 50 shown in FIG. 10 has all the elements of the optoelectronic component 50 shown in FIG. 9 except that the shell 60 is provided only at the topmost portion of the wire 52. Therefore, the optoelectronic component 50 is called an axial configuration.

[0064] According to an embodiment, the wire 52 is at least partially formed of at least one semiconductor material. The semiconductor material is selected from the group including III-V compounds, II-VI compounds, group-IV semiconductors and compounds. The wire 52 may be at least partially formed of a semiconductor material mainly including a III-V compound, for example, a III-N compound. Examples of group-III elements include gallium (Ga), indium (In) or aluminum (Al). Examples of III-N compounds include GaN, AlN, InN, InGaN, AlGaN or AlInGaN. Other group-V elements, for example, phosphorus or arsenic may be further used. The wire 52 may be at least partially formed of a semiconductor material mainly including a II-VI compound. Examples of group-II elements include group-IIA elements, particularly beryllium (Be) and magnesium (Mg), and group-IIB elements, particularly zinc (Zn), cadmium (Cd) and mercury (Hg). Examples of group-VI elements include group-VIA elements, particularly oxygen (O) and tellurium (Te). Examples of II-VI compounds include ZnO, ZnMgO, CdZnO, CdZnMgO, CdHgTe, CdTe or HgTe. Generally, the elements in the III-V compound or the II-VI compound may be combined at different molar fractions. The wire 52 may be at least partially formed of a semiconductor material mainly including at least one group-IV compound. Examples of group-IV semiconductor materials include silicon (Si), carbon (C), germanium (Ge), silicon carbide (SiC) alloy, silicon-germanium (SiGe) alloy or germanium carbide (GeC) alloy. The wire 52 may contain a dopant. For example, regarding III-V compounds, the dopant may be selected from the group including P-type group-II dopants such as magnesium (Mg), zinc (Zn), cadmium (Cd) and mercury (Hg), P-type group-IV dopants such as carbon (C), and N-type group-IV dopants such as silicon (Si), germanium (Ge), selenium (Se), sulfur (S), terbium (Tb) and tin (Sn).

[0065] The seed structure 54 is formed of a material that facilitates the growth of the wire 52. By way of example, the material forming the pads 46 may be a nitride, carbide, or boride of a transition metal in column IV, V, or VI of the periodic table of the elements, or a combination of these compounds. By way of example, each pad 46 may be aluminum nitride (AlN), aluminum oxide (Al 2 O 3 ), boron (B), boron nitride (BN), titanium (Ti), titanium nitride (TiN), tantalum (Ta), tantalum nitride (TaN), hafnium (Hf), hafnium nitride (HfN), niobium (Nb), niobium nitride (NbN), zirconium (Zr), zirconium boride (ZrB 2 ), zirconium nitride (ZrN), silicon carbide (SiC), tantalum carbonitride (TaCN), or magnesium nitride in the form of Mg x N y (where x is approximately 3 and y is approximately 2, for example magnesium nitride in the form of Mg 3 N 2 ).

[0066] The insulating layers 58, 66 may be formed of a dielectric material, such as silicon oxide (SiO 2 ), silicon nitride (Si x N y , where x is approximately 3 and y is approximately 4, for example Si 3 N 4 ), silicon oxynitride (for example Si x N y of the general formula SiO x N y ), such as Si 2 ON 2 ), hafnium oxide (HfO 2 ), or diamond, respectively.

[0067] The active layer 62 may have confinement means such as a single quantum well or multiple quantum wells. The active layer 62 can be obtained, for example, by alternately forming GaN layers with a thickness of 5 - 20 nm (e.g., 8 nm) and InGaN layers with a thickness of 1 - 10 nm (e.g., 2.5 nm). The GaN layer may be doped, for example, N-type or P-type. According to another example, the active layer may have, for example, one InGaN layer with a thickness greater than 10 nm.

[0068] For example, the semiconductor layer 64 doped P-type may correspond to a stack of semiconductor layers, enabling a P-N junction or a P-I-N junction, and the active layer 62 is provided between the P-type intermediate layer of the P-N junction or P-I-N junction and the N-type wire 52.

[0069] The electrode layer 68 can polarize the active layer of the light-emitting diode and allow the electromagnetic radiation emitted by the light-emitting diode to pass through. The material forming the electrode layer 68 may be a transparent conductive material such as indium tin oxide (ITO), pure zinc oxide, aluminum zinc oxide, gallium zinc oxide, graphene, or silver nanowires. By way of example, the thickness of the electrode layer 68 is in the range of 5 nm to 200 nm, preferably in the range of 30 nm to 100 nm.

[0070] The encapsulation layer 72 may be formed of an organic material or an inorganic material and at least partially allow the radiation light emitted by the light-emitting diode to pass through. The encapsulation layer 72 may have a lumophore, and when the lumophore is excited by the light emitted by the light-emitting diode, it can emit light at a wavelength different from the wavelength of the light emitted by the light-emitting diode.

[0071] The first simulation was performed. In these first simulations, the photonic crystal layer 40 has columnar bodies 46 formed of silicon, and the base layer 44 is SiO 2It is formed. The columnar bodies 46 are dispersed in a hexagonal lattice, and each columnar body 46 has a circular cross-section with a diameter D of 0.97 μm. In the first simulation, the thickness L of the columnar bodies 46 was 1 μm. The absorption layer 42 had a thickness of 50 nm, a refractive index of 4.5, and an absorption coefficient of 3.75.

[0072] FIG. 11 shows curves C1 and C2 of the change in the average absorption rate Abs of the absorption region 28 according to the ratio a / λ of the pitch a to the wavelength λ of the laser. Curve C1 was obtained when the absorption region 28 has the structure shown in FIG. 4, and curve C2 was obtained when the absorption region 28 has no photonic crystal layer 40 and has only the absorption layer 42. When the photonic crystal layer 40 does not exist, the average absorption rate of the absorption region 28 is approximately 55%. When the photonic crystal layer 40 exists, the average absorption rate exceeds 55% over a plurality of ranges of the ratio a / λ, and reaches 90% when the ratio a / λ is approximately 0.75.

[0073] The second simulation was performed. In these second simulations, the photonic crystal layer 40 has columnar bodies 46 formed of silicon, and the base layer 44 is SiO 2 It is formed. The columnar bodies 46 are dispersed in a hexagonal lattice, and each columnar body 46 has a circular cross-section. In the second simulation, the thickness L of the columnar bodies 46 was 1 μm.

[0074] FIGS. 12 and 13 respectively show, in grayscale, depth maps of the average absorption rate Abs of the absorption region 28 according to the ratio a / λ on the abscissa and the filling factor FF on the ordinate. The filling factor FF corresponds to the ratio of the total area of the columnar bodies 46 in plan view to the total area of the photonic crystal layer 40. As an example, for columnar bodies 46 having a circular cross-section, the filling factor FF is given by the following relational expression [Equation 1].

[0075]

Equation

[0076] In FIG. 12, regions A and B can be identified, and in FIG. 13, region B' can be identified. In these regions, the average absorption rate Abs exceeds approximately 70%. Regions B and B' are obtained with respect to a ratio a / λ in the range of 0.1 to 1 and a filling factor FF in the range of 1% to 50%, and region A is obtained with respect to a ratio a / λ in the range of 0.5 to 2 and a filling factor FF in the range of 10% to 70%.

[0077] FIG. 14 shows a curve C3 of the change in the average absorption rate Abs according to the height L of the columnar body 46 with respect to a filling factor FF of 0.3 and a ratio a / λ of 0.6.

[0078] FIG. 15 shows a curve C4 of the change in the average absorption rate Abs according to the height L of the columnar body 46 with respect to a filling factor FF of 0.5 and a ratio a / λ of 0.6.

[0079] Curves C3 and C4 show local maximum values corresponding to Fabry - Perot resonances at different orders, and FIGS. 14 and 15 show the corresponding values of the height L. It is preferable to select the height L of the columnar body 46 that is substantially at one level within the Fabry - Perot resonance.

[0080] FIGS. 16 to 22 are partial cross - sectional schematic views showing the structures obtained in successive steps of a manufacturing method for manufacturing a device 20 having the structure in which the absorption region 28 is shown in FIG. 2. The manufacturing method includes - a step of manufacturing a substrate 22 (FIG. 16), - a step of etching an opening 80 in the substrate 22 to a depth substantially equal to the desired height L (the cross - section of the opening 80 corresponds to the desired cross - section of the columnar body 46) (FIG. 17), - a step of depositing a layer 82 of a second material covering the substrate 22 and in particular filling the opening 80 (FIG. 18), - a step of etching the layer 82, for example, by chemical - mechanical polishing (CMP) until reaching the substrate 22, and retaining only a part of the layer 82 in the opening 80 to form the columnar body 46 of the photonic crystal layer 40 (a part of the substrate 22 surrounding the columnar body 46 forms the base layer 44 of the photonic crystal layer 40) (FIG. 19). - A step of depositing or growing an absorption layer 42 on a photonic crystal layer 40 (FIG. 20), - A step of forming a layer stack 84 on the absorption layer 42 (FIG. 21), and - A step of etching the layer stack 84 to the absorption layer 42 using, for example, an etching mask 86 to define an object 30 (FIG. 22) (one object is particularly shown in FIG. 22) It has.

[0081] FIGS. 23 to 26 are partial cross-sectional schematic views showing structures obtained in consecutive steps of another embodiment of the laser processing method of the device 20.

[0082] FIG. 23 shows the structure obtained after the manufacture of the device 20.

[0083] FIG. 24 shows the structure obtained after the object 30 is joined to the support 90 by bringing the device 20 into contact with the support 90. According to an embodiment, the joining of the object 30 to the support 90 may be performed by a hybrid molecular joining of the object to the support 90. According to an embodiment, the support 90 may have a pad 92 at the joining position of the object 30. Therefore, until the object 30 contacts the pad 92, the device 20 and the support 90 approach each other. According to an embodiment, not all the objects 30 joined to the support 22 are configured to be transferred to the same support 90. For this reason, the support 90 may have a pad 92 only for the object 30 transferred to the support 90. In this case, when the device 20 and the support 90 approach each other until a part of the object 30 contacts the pad 92, the object 30 not in front of the pad 92 does not contact the support 90 and thus is not joined to the support 90.

[0084] FIG. 25 shows the structure obtained during the passage of the laser 18 to separate the object 30 transferred to the support 90 from the substrate 22. During operation, it is preferable that the focus of the laser beam 18 is aligned with the absorption region 28. The photonic crystal layer 40 of the absorption region 28 makes it possible to enhance the absorption of the laser light by the absorption region 28.

[0085] When the absorption region 28 has the absorption layer 42, the photonic crystal layer 40 can particularly enhance the absorption of the light of the laser 18 by the absorption layer 42. Therefore, ablation of the absorption layer 42 becomes possible. When the columnar body 46 or the base layer 44 is formed of a material that absorbs the laser 18, the photonic crystal layer 40 can particularly enhance the absorption of the laser light by the columnar body 46 or the base layer 44. Therefore, ablation of the photonic crystal layer 40 becomes possible.

[0086] When the absorption layer 42 is not provided and neither the material forming the columnar body 46 of the photonic crystal layer 40 nor the material forming the base layer 44 of the photonic crystal layer 40 has an absorption coefficient k in the range of 1 to 10 at the wavelength of the laser in the linear mode, the photonic crystal layer 40 can locally increase the energy density in the photonic crystal layer 40 and in the vicinity of the photonic crystal layer 40. Therefore, the absorption of the laser can be enhanced by the non-linear absorption phenomenon in the photonic crystal layer 40 and in the vicinity of the photonic crystal layer 40, particularly on the substrate 22, and ablation of the photonic crystal layer 40 is performed. Since the photonic crystal layer 40 is provided, a non-linear absorption phenomenon occurs in the photonic crystal layer 40 and / or in the vicinity of the photonic crystal layer 40, particularly on the substrate 22, and it is possible to reduce the intensity of the laser.

[0087] When the substrate 22 is formed of a semiconductor material, particularly silicon, it may be necessary to set the wavelength of the laser in the infrared region so that the substrate 22 transmits the laser. However, commercially available infrared lasers generally have a lower maximum energy than other commercially available lasers of other frequencies. The use of the photonic crystal layer 40 is advantageous in that laser cutting can be performed even when using an infrared laser, and thus it is advantageous that a semiconductor substrate 22 formed particularly of silicon can be used.

[0088] FIG. 26 shows a structure obtained after separating the substrate 22 from the support 90. The object 30 joined to the support 90 is separated from the substrate 22.

[0089] In the above-described embodiment, the columnar bodies 46 are dispersed in a regular lattice pattern. According to another embodiment, in order to change the dispersion of the energy density in the vicinity of the photonic crystal layer 40 and / or the photonic crystal layer 40, there may be a missing portion in the lattice arrangement of the columnar bodies 46. The missing portion may correspond to the columnar bodies 46 not being provided in the case of the lattice arrangement of the columnar bodies 46, or may correspond to the columnar bodies 46 having a size different from the size of the adjacent columnar bodies, for example, in the case of columnar bodies having a circular cross section, the columnar bodies 46 having a diameter D different from the diameter of the adjacent columnar bodies are provided.

[0090] FIG. 27 is a plan view similar to FIG. 5 in which the columnar bodies 46 are missing in the lattice arrangement of the columnar bodies 46.

[0091] FIG. 28 is a chart similar to FIG. 11 obtained with the arrangement shown in FIG. 27. An average absorption rate Abs exceeding 90% is obtained at a ratio a / λ of approximately 0.53.

[0092] FIG. 29 is a grayscale depth map showing the energy density obtained on a plane parallel to the surface 26 and 0.6 μm away from the surface 26 in the photonic crystal layer 40 in the arrangement shown in FIG. 27 when the ratio a / λ is approximately 0.66 at a filling rate of 0.7. As shown in FIG. 29, the energy density locally increases at the position of the missing columnar bodies. Therefore, it is possible to specify the maximum value of the peak of the energy density even for the average absorption rate. According to the embodiment, the missing portions of the lattice arrangement of the photonic crystal layer are dispersed so as to be at the level of the object 30 where the maximum value of the peak of the energy is shifted. Therefore, even when the positioning accuracy of the laser 18 is low, it is possible to obtain the peak of the energy density at an accurate position. Since the missing portions are provided, it is possible to arrange the region with the highest absorption at a desired position.

[0093] FIG. 30 is a plan view similar to FIG. 5 in which the columnar body 46 has a larger diameter than the other columnar bodies in the arrangement of the columnar bodies of the photonic crystal layer 40. Depending on the parameter a and the parameter D, the energy density distribution may have a general shape similar to the shape of FIG. 29.

[0094] Various embodiments and modifications are described. Those skilled in the art will understand that they can combine certain features of these various embodiments and modifications, and other modifications will be recalled by those skilled in the art. Finally, the actual implementation of the described embodiments and modifications is within the scope of the skills of those skilled in the art based on the functional representations described above.

[0095] This patent application claims the priority of French Patent Application No. 19 / 15606, which is incorporated herein by reference.

Claims

1. A device configured to be processed by a laser, comprising: a substrate through which the laser passes; and an object respectively joined to the substrate via an absorption region for the laser, the absorption region including a photonic crystal. The photonic crystal is configured to enhance absorption of the laser by the absorption region, and the absorption region is configured such that ablation is at least partially performed by the action of the laser that separates the object from the substrate.

2. The device according to claim 1, wherein the photonic crystal is a two-dimensional photonic crystal.

3. The device according to claim 1 or 2, wherein the photonic crystal has a base layer of a first material and columnar bodies arranged in a lattice pattern of a second material different from the first material, and the columnar bodies respectively extend into the base layer over at least a part of the thickness of the base layer.

4. The device according to claim 3, wherein the first material has an absorption coefficient of less than 1 with respect to the laser.

5. The device according to claim 3 or 4, wherein the second material has an absorption coefficient of less than 1 with respect to the laser.

6. The device according to claim 5, wherein the substrate is formed of the second material.

7. The device according to claim 3 or 4, wherein the second material has an absorption coefficient in the range of 1 to 10 with respect to the laser.

8. The device according to any one of claims 1 to 7, wherein the substrate has a first surface and a second surface facing each other, the laser is configured to cross the substrate from the first surface to the second surface, and the photonic crystal covers the second surface.

9. The device according to any one of claims 1 to 8, further comprising a layer that absorbs the laser between the object and the substrate.

10. The device according to claim 9, further comprising at least one layer through which the laser passes, the at least one layer being disposed between the photonic crystal and the layer that absorbs the laser.

11. The device according to any one of claims 1 to 10, wherein the substrate is formed of at least two mixtures or alloys of silicon, germanium, or compounds thereof.

12. ​ The device according to claim 3, wherein the object has at least one optoelectronic component having a three-dimensional semiconductor element covered with an active layer, and the three-dimensional semiconductor element has a base in contact with at least one of the columns.

13. The device according to claim 12, wherein the second material is a nitride, carbide, or boride of a transition metal in column IV, V, or VI of the periodic table of elements, or a combination of these compounds, or aluminum nitride, aluminum oxide, boron, boron nitride, titanium, titanium nitride, tantalum, tantalum nitride, hafnium, hafnium nitride, niobium, niobium nitride, zirconium, zirconium boride, zirconium nitride, silicon carbide, tantalum carbonitride, magnesium nitride, or a mixture of at least two of these compounds.

14. A method of manufacturing the device according to any one of claims 1 to 13, forming the photonic crystal to form the object.

15. The method according to claim 14, wherein the object is formed on the photonic crystal by forming the photonic crystal on the substrate and depositing and / or growing a layer on the photonic crystal.

16. A method of processing the device according to any one of claims 1 to 13 with a laser, irradiating the photonic crystal with a laser beam through the substrate.

17. The method according to claim 16, wherein the object is joined to a support, the object remains connected to the substrate, and a region including the photonic crystal or a region adjacent to the photonic crystal is destroyed by a laser.

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