JP4043794B2 - Method of mounting nitride compound semiconductor device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for mounting a nitride-based compound semiconductor device, and more specifically, a method for mounting a nitride-based compound semiconductor device that enables accurate alignment without requiring a special positioning mark. It is about.
[0002]
[Prior art]
Nitride compound semiconductors (hereinafter referred to as nitride compound semiconductors) such as GaN, AlGaN, GaInN, AlGaInN, and AlBGaInN generally have band gap energy compared to III-V group compound semiconductors such as AlGaInAs and AlGaInP. Eg is large and it is a direct transition semiconductor.
Due to this feature, these nitride-based compound semiconductors are attracting attention as materials for producing semiconductor light-emitting elements such as semiconductor laser elements that emit light in a wide wavelength range from the ultraviolet region to red and light-emitting diodes (LEDs). Has been.
These semiconductor light-emitting elements are being widely applied as light sources for recording / reproducing optical pickups of high-density optical disks, light-emitting elements for full-color displays, and other light-emitting devices in fields such as environment and medicine.
[0003]
These nitride-based compound semiconductors have, for example, a high saturation rate of GaN in a high electric field region, or a nitride-based compound semiconductor is insulated as a semiconductor layer when forming a MIS (Metal-Insulator-Semiconductor) structure. A feature is that aluminum nitride (AlN) is used as the layer, and the semiconductor layer and the insulating layer can be continuously crystal-grown.
Due to this feature, nitride-based compound semiconductor devices are attracting attention as electronic devices that have high saturation drift speed and electrostatic breakdown voltage, and are excellent in high-speed operability, high-speed switching performance, large current operability, and the like.
[0004]
In addition, nitride compound semiconductors are (1) more highly conductive than GaAs, etc., and are therefore more advantageous as materials for high-power devices at high temperatures than GaAs. (2) Chemically stable materials In addition, since it has high hardness, it can be evaluated as a highly reliable element material.
[0005]
In general, when a semiconductor film is grown on a substrate, a bulk substrate similar to the growth film or having a lattice constant close to that is used as the substrate. Therefore, in the case of a nitride-based semiconductor element, for example, a GaN substrate made of the same nitride-based semiconductor is desirable. However, a GaN substrate is manufactured in a small size under ultra-high pressure and ultra-high temperature. Therefore, it is extremely difficult to produce a substrate having a large size practically.
SiC substrates, ZnO substrates, and MgAl ₂ O ₄ substrates have also been used as substrates for nitride-based semiconductor devices, but in general, nitride-based semiconductor devices are most often fabricated on sapphire substrates.
[0006]
The sapphire substrate is supplied with a high quality, low cost, and a size of 2 inches or more. However, the sapphire substrate has a problem of large lattice mismatch and a large difference in thermal expansion coefficient from GaN, which is a typical nitride semiconductor. In addition, the sapphire substrate is not cleaved, has low electrical conductivity, and is electrically insulated.
For example, since the lattice mismatch between sapphire and GaN is about 13%, which is large, a buffer layer is provided between the sapphire substrate and the GaN layer to alleviate the mismatch, and a good single crystal GaN layer is epitaxially grown. However, the defect density reaches, for example, about 10 ⁸ to 10 ⁹ cm ⁻² , which adversely affects the operation reliability of the semiconductor element.
[0007]
(1) Since the difference in thermal expansion coefficient between the sapphire substrate and the GaN layer is large, if the crystal growth film is thick, the warpage of the substrate becomes large even at room temperature, and there is a concern about the occurrence of cracks. (2) The sapphire substrate has no cleaving property and it is difficult to stably form a laser facet with high specularity. Furthermore, (3) sapphire is insulative, so GaAs It is difficult to provide one electrode on the back surface of the substrate as in a semiconductor laser device, and it is necessary to provide both the p-side electrode and the n-side electrode on the nitride compound semiconductor laminated structure side on the substrate. Becomes wider and the process becomes complicated.
[0008]
In view of this, research has been actively conducted to produce a nitride compound semiconductor, in particular, a GaN single crystal substrate lattice-matched with a GaN compound semiconductor by an industrially easy method.
As one of them, for example, Japanese Patent Application Laid-Open No. 2001-102307 discloses that a growth surface of vapor phase growth is not in a flat state but has a three-dimensional facet structure, and the facet structure is embedded while the facet structure is maintained. Disclosed is a crystal growth method for single-crystal gallium nitride in which dislocations are reduced by growing without crystal. According to this method, a GaN single crystal layer can be produced by growing a GaN single crystal layer on a GaAs substrate through a windowed mask and slicing the grown GaN single crystal layer.
[0009]
By the way, when a nitride compound semiconductor device is incorporated as a system component, packaging suitable for the purpose of the system is required.
For example, in the case of an optical system element such as a semiconductor laser element, when mounting a package, the light emitting position with respect to the base on which the package is mounted, that is, the positioning of the emission end face is directly related to light wavefront accuracy, high-speed modulation, coupling with an optical fiber, etc. Since it affects the photoelectric characteristics, accurate control of positioning is required. Furthermore, since the package mounting itself is an important operation that greatly affects the seismic resistance, heat dissipation, moisture resistance, etc. of the semiconductor laser device, sufficient consideration is required.
For example, the semiconductor laser element is extremely small and weak against external force, and is thus die-bonded on a submount made of AlN or the like. In addition, since the semiconductor laser element has high heat generation properties, a submount in which the semiconductor laser element is die-bonded is further bonded onto a heat sink to enhance heat dissipation.
[0010]
When a semiconductor laser element is integrated on a semiconductor substrate or an optical crystal substrate to produce an integrated element, the semiconductor laser element is integrated on a base such as a semiconductor substrate or an optical crystal substrate by a combination of process steps. There is monolithic integration and hybrid integration in which a semiconductor laser element is integrated by die bonding in a mounting process on a base such as a semiconductor substrate or an optical crystal substrate manufactured in a process different from the process of forming a semiconductor laser element.
Hybrid integration has the advantage that a wide range of materials can be combined, and that a highly functional and integrated device can be fabricated compared to monolithic integration.
[0011]
In hybrid integration and package mounting, there are a manual type and an automatic type as a positioning method of an element, for example, a semiconductor laser element.
The manual type method is a method in which a human visually aligns a semiconductor laser element and a base. For example, as shown in FIG. 7A, when the semiconductor laser element 80 is mounted on the heat sink 82, the emission end face of the semiconductor laser element 80 and the front surface of the heat sink 82 are aligned with each other, and then on the heat sink 82. The distance between the positioning mark 84 and the side wall of the semiconductor laser element 80 is visually measured to position the semiconductor laser element 80 at a predetermined position.
[0012]
7B, when the semiconductor laser element 80 is mounted on the heat sink 82 via the submount 86, the emission end face of the semiconductor laser element 80, the front surface of the submount 86, and the heat sink 82 The front surface is flush with the front surface, then the submount 86 is positioned on the heat sink 82, and then the distance between the mark 88 on the submount 86 and the side wall of the semiconductor laser device 80 is visually measured. Is positioned at a predetermined position.
[0013]
On the other hand, in the automation type method, positioning marks are provided on both the semiconductor laser element and the base, the base is placed on an XY stage, and the position is used as a signal using a CCD camera with reference to the positioning mark. This is a method of performing positioning automatically by taking in and controlling the position by software and an XY stage.
In other words, both the manual type method and the automation type method require a mark, and the difference between the two is that the distance between the positioning mark of the semiconductor laser element and the positioning mark of the base is visually observed, or a CCD camera is used. The only difference is what to do.
[0014]
[Problems to be solved by the invention]
By the way, as the function and complexity of the nitride compound semiconductor element and the integrated element increase, the number of elements to be integrated increases, and so on, precise position control is required, and the required precision of positioning is extremely high.
Since the displacement due to the positioning failure has a great influence on the yield and cost of the product, there is a need for a device mounting method that can perform positioning with higher accuracy than conventional devices when mounting the device.
Moreover, unlike compound semiconductor elements formed on a GaAs substrate or InP substrate, nitride-based compound semiconductor elements have poor cleavage and it is difficult to accurately form the outer edge of the element serving as a positioning mark with good reproducibility. The individual difference is extremely large. Therefore, in the conventional positioning method described above, an error is likely to occur in the distance measurement, and it has been difficult to position accurately.
[0015]
Accordingly, an object of the present invention is to provide a method for mounting a nitride-based compound semiconductor element that enables accurate positioning using the characteristics of a semiconductor substrate when mounting a nitride-based compound semiconductor element. is there.
[0016]
[Means for Solving the Problems]
In the course of research to solve the above-mentioned problems, the present inventor has developed GaN developed as a semiconductor substrate having a novel configuration in which high-density defect regions are regularly, for example, periodically arranged in low-density defect regions. We focused on single crystal substrates.
This GaN single crystal substrate has been developed by improving the technique disclosed in Japanese Patent Laid-Open No. 2001-102307 and controlling the position of the high-density defect region generated in the low-density defect region.
[0017]
The developed high-density defect region arrangement pattern of the semiconductor substrate can be freely selected, for example, a square lattice arrangement as shown in FIG. 8, a rectangular lattice arrangement as shown in FIG. As shown in 9 (b), there is a hexagonal lattice arrangement. FIGS. 8A and 8B are a plan view and a cross-sectional view of a GaN substrate for explaining a high-density defect region, respectively.
Further, the arrangement pattern of the high-density defect area is not limited to the distributed pattern as described above. For example, as shown in FIG. 10A, the dot-like high-density defect area is intermittently arranged linearly. In addition, as shown in FIG. 10B, it is possible to produce a structure in which high-density defect regions are continuous in a linear shape.
[0018]
Here, a method for manufacturing a GaN single crystal substrate will be described.
The basic crystal growth mechanism of a GaN single crystal is to grow with a slope consisting of facets, and maintain and maintain the facets slope to propagate the dislocations and collect the dislocations in place. Let The region grown by this facet surface becomes a low defect region due to dislocation movement.
On the other hand, the growth is carried out with a high-density defect region with a clear boundary at the lower part of the facet slope, and dislocations gather at the boundary of the high-density defect region or inside, and disappear here. Or accumulate.
[0019]
The shape of the facet surface varies depending on the shape of the high-density defect region. When the defect area is dot-shaped, the facet surface is surrounded with the dot as the bottom, and a pit composed of the facet surface is formed.
In addition, when the defect region has a stripe shape, it becomes a triangular prism-shaped facet surface that has a stripe as a valley bottom, has facet inclined surfaces on both sides thereof, and lies sideways.
[0020]
This dense defect area can have several states. For example, it may be made of polycrystal. Moreover, although it is a single crystal, it may be slightly inclined with respect to the surrounding low defect area | region. In addition, the C axis may be inverted with respect to the surrounding low defect area. Thus, this high density defect area has a clear boundary and is distinguished from the surroundings.
By growing with this high defect density region, the growth can proceed while maintaining the facet surface without embedding the facet surface around the region.
Then, by grinding and polishing the surface of the GaN growth layer, the surface can be flattened and used as a substrate.
[0021]
This method of forming a high-density defect region can be generated by pre-forming seeds in a place where the high-density defect region is to be formed when GaN is grown on a base substrate. . As the seed, an amorphous or polycrystalline layer is formed in a micro region serving as a seed. On top of that, by growing GaN, a high-density defect region can be formed in that kind of region.
[0022]
A specific method for manufacturing the GaN single crystal substrate is as follows. First, a base substrate on which a GaN layer is grown is used. The base substrate is not necessarily specified and may be a general sapphire substrate, but a GaAs substrate or the like is preferable in consideration of removing the base substrate in a later step.
For example, seeds made of, for example, a SiO ₂ layer are regularly and periodically formed on the base substrate. The shape of the seed is a dot shape or a stripe shape according to the arrangement and shape of the high-density defect region.
Thereafter, GaN is grown in a thick film by a Hydrocarbon Vapor Phase Epitaxy (HVPE). After the growth, a facet surface corresponding to the pattern shape of the seed is formed on the surface. For example, when the seed is a dot-like pattern, pits composed of facet surfaces are regularly formed, and when the seed is a stripe shape, a prism-like facet surface is formed.
[0023]
After the GaN layer is grown, the base substrate is removed, and the thick film layer of GaN is ground and polished to flatten the surface. Thereby, a GaN substrate can be manufactured. The thickness of the GaN substrate can be freely set.
The GaN substrate manufactured in this way has a C-plane as a main surface, in which a high defect density region of a predetermined size of dots or stripes is regularly formed. The single crystal region other than the high defect density region is a low dislocation density region in which the dislocation density is significantly lower than that of the high defect density region.
[0024]
The present inventor has found that the above-described high-density defect region of the GaN substrate is a region where a component of the nitride-based compound semiconductor element should not be provided due to many crystal defects, but accurate positioning as described above. We focused on the fact that high-density defect regions were generated there.
Then, the inventors came up with the idea of mounting a nitride-based compound semiconductor element using the high-density defect region as a positioning mark, and came to invent the present invention after the experiment.
In the above description, the semiconductor laser element has been mainly described as an example, but this applies to all nitride-based compound semiconductor elements.
[0025]
In order to achieve the above object, the nitride-based compound semiconductor device mounting method according to the present invention includes a high-density defect penetrating the substrate in a periodic array on the substrate surface as a region where the crystal defect density is higher than the surroundings. A method of mounting a nitride compound semiconductor device comprising a nitride compound semiconductor laminated structure on a semiconductor crystal substrate having a region,
A hole is formed so as to penetrate or not penetrate the substrate of the core region having the highest defect density in the high-density defect region, and then a nitride-based compound semiconductor laminated structure is formed on the substrate, and the chip is formed into a nitride. After producing a compound semiconductor device, when die-bonding a nitride compound semiconductor device on a base,
In positioning the nitride compound semiconductor element on the base, the nitride compound semiconductor element is irradiated with light to detect the position of the hole, and the hole is used as a positioning mark. It is characterized by positioning on the base.
[0026]
In the present invention, a through hole is not necessarily required as a hole for opening the substrate in the core region, and may be a blind hole halfway through the substrate. The diameters of the through hole and the blind hole are arbitrary, and are not limited as long as the hole can be detected by the irradiated light.
The high-density defect region is a columnar region that penetrates the substrate, and the cross-sectional shape of the high-density defect region is arbitrary.
In the present invention, the active region of the laminated structure of the nitride-based compound semiconductor layers constituting the nitride-based compound semiconductor element is provided on the low-density defect region between the high-density defect region and the high-density defect region.
[0027]
The nitride compound semiconductor element of the present invention is a concept including a nitride semiconductor laser element, a nitride semiconductor light emitting diode, a nitride compound semiconductor electronic element, and the like.
The semiconductor crystal substrate is not limited in its composition as long as it has a high-density defect region penetrating the substrate in a periodic arrangement on the substrate surface as a region where the crystal defect density is higher than the surroundings.
The nitride-based compound semiconductor, refers _{Al a B b Ga c In d} N (a + b + c + d = 1,0 ≦ a, b, c, d ≦ 1) a.
[0028]
The nitride-based compound semiconductor device mounting method according to the present invention uses a hole provided in a high-density defect region generated accurately and with high reproducibility as a positioning mark. The nitride-based compound semiconductor element can be accurately positioned on the base without providing a separate positioning mark.
[0029]
In the method of the present invention, the arrangement pattern of the high-density defect region is free. Specifically, the high-density defect region is periodically formed on the substrate surface of the semiconductor crystal substrate, for example, a square lattice shape, a rectangular lattice shape, And may be scattered in any arrangement of a hexagonal lattice.
In addition, the high-density defect regions are linear high-density defect regions that are periodically and spaced apart from each other on the substrate surface of the semiconductor crystal substrate, and the dotted high-density defect regions are The high-density defect area | region which is mutually arrange | positioned or intermittently arrange | positioned at linear form, or the high-density defect area | region where a high-density defect area | region extends linearly continuously may be sufficient.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below specifically and in detail with reference to the accompanying drawings. It should be noted that the composition and process conditions of the compound semiconductor layer shown in the following embodiment examples are merely examples for facilitating understanding of the present invention, and the present invention is not limited to these examples.
Embodiment 1
This embodiment is an example of an embodiment of a nitride compound semiconductor device mounting method according to the present invention, and FIG. 1 shows a configuration of a nitride semiconductor laser device to which the method of this embodiment is applied. Cross-sectional views and FIGS. 2A to 2C are cross-sectional views and perspective views for each step in fabricating a nitride-based semiconductor laser device to which the method of this embodiment is applied, respectively. FIG. 3 is a flowchart for explaining the chip forming process and the mounting process, and FIG. 4 is a perspective view for explaining the positioning of the nitride-based semiconductor laser device by applying the method of this embodiment. FIGS. 8A and 8B are a plan view and a cross-sectional view showing the arrangement of high-density defect regions on the GaN substrate of the nitride-based semiconductor laser device of this embodiment, respectively.
[0031]
As shown in FIGS. 8A and 8B, the GaN substrate 76 on which the nitride-based semiconductor laser device 10 of this embodiment is formed has a so-called high-density defect region in which the crystal defect density is higher than the surrounding region. 78 has a characteristic that it penetrates the GaN substrate 76 and is present in a square square lattice arrangement on the substrate surface in a plan view. The next n-type GaN substrate 12 is a part of the GaN substrate 76 as shown in FIG. 11A, and 90 indicates a laser stripe.
[0032]
The nitride-based semiconductor laser device 10 mounted in the present embodiment is an edge-emitting semiconductor laser device having a resonator length of 600 μm, and as shown in FIG. n-type GaN layer 14, Si-doped n-type AlGaN cladding layer 16, Si-doped n-type GaN optical waveguide layer 18, active layer 20 having a multiple quantum well structure, Mg-doped p-type GaN optical waveguide layer 22, Mg-doped p-type AlGaN A laminated structure of the cladding layer 24 and the Mg-doped p-type GaN contact layer 26 is provided.
The nitride-based semiconductor laser device 10 includes a striped p-side electrode 28 on the p-type GaN contact layer 26 and a striped n-side electrode 30 on the back surface of the n-type GaN substrate 12.
[0033]
Further, the nitride-based semiconductor laser device 10 includes a through hole 32 having a diameter of 50 μm that penetrates at least one row of the core portions 12 a in the high-density defect region of the type GaN substrate 12. The core portion 12a is a portion having a particularly high crystal defect density in the high-density defect region, and a region between the through holes 32 is a low-density defect region.
In the present embodiment, the diameter of the through hole 32 is 50 μm, but it is not necessary to be 50 μm, and there is no restriction as long as the hole can be detected by the irradiated light. For example, it is about several μm to 100 μm, preferably not more than the diameter of the core portion 12a. The reason why the diameter is smaller than the diameter of the core portion 12a is that the core portion has a high crystal defect density, and therefore it is easy to provide a through hole.
The n-side electrode 30 is provided so as to be positioned between the core portion 12 a and the adjacent core portion 12 a, and the p-side electrode 28 is provided just above the n-side electrode 30.
[0034]
In the method of the present embodiment, first, as shown in FIG. 2A, the core of the high-density defect region of the n-type GaN substrate 12 having periodically high-density defect regions whose crystal defect density is higher than the surrounding region. A through hole 32 is provided in one row of the portion 12a. The core portion 12a is a portion having a particularly high crystal defect density even in the high-density defect region, and a region between the core portion 12a and the core portion 12a is a low-density defect region having a low crystal defect density.
When opening the through-hole 32, the through-hole 32 having a diameter of 50 μm that penetrates the core portion 12a is easily formed by wet etching using KOH or phosphoric acid as an etchant by using the crystal defect density. Can do. In this embodiment, the diameter of the through hole 32 is smaller than the diameter of the core portion 12a.
[0035]
The etching method for opening the through holes 32 is not limited to the wet etching method using KOH or phosphoric acid as an etchant, and a dry etching method or a thermal etching method can be applied.
[0036]
Next, on the n-type GaN substrate 12, as shown in FIG. 2B, for example, by MOCVD (Metalorganic Chemical Vapor Deposition), for example, at a growth temperature of 1000 ° C., sequentially, Si-doped. The GaN layer 14 is grown to a thickness of 3.0 μm, the Si-doped n-type AlGaN cladding layer 16 is grown to a thickness of 0.5 μm, and the Si-doped n-type GaN optical waveguide layer 18 is grown to a thickness of 0.1 μm.
Subsequently, the active layer 20 having a multiple quantum well structure made of, for example, Ga _1-x In _x N (well layer) and Ga _1-y In _y N (barrier layer) is grown to a thickness of 40 nm at a growth temperature of 800 ° C. .
Further, at a growth temperature of 1000 ° C., the Mg-doped p-type GaN optical waveguide layer 22 has a thickness of 0.1 μm, the Mg-doped p-type AlGaN cladding layer 24 has a thickness of 0.5 μm, and the Mg-doped p-type GaN contact layer 26 sequentially. Is grown to a thickness of 0.5 μm.
[0037]
Next, as shown in FIG. 2C, for example, palladium, platinum, and gold are sequentially deposited on the p-type contact layer 26 to form a striped p-side electrode 28. Next, the back surface of the n-type GaN substrate 12 is polished and thinned, and then, for example, titanium, platinum, and gold are sequentially deposited on the back surface of the substrate to form a striped n-side electrode 30.
[0038]
Next, as shown in FIG. 3, the substrate (wafer) having the above-described structure is cleaved into bars so that the resonator length becomes 600 μm, and then an end face reflection film (not shown) is formed on the resonator end face. Film. Thereby, the nitride-based semiconductor laser device 10 shown in FIG. 1 can be completed.
Next, as shown in FIG. 4, the nitride-based semiconductor laser device 10 is die-bonded on the heat sink 40 by a junction down method, and subsequently provided on the n-side electrode 30 and the heat sink 40 of the nitride-based semiconductor laser device 10. The external terminals (not shown) are wire-bonded. Here, the junction down method is a method in which the p-side electrode 28 is bonded onto the heat sink 40. Of course, a junction-up system in which the n-side electrode 30 is bonded onto the heat sink 40 may be used.
Then, the characteristics of the nitride semiconductor laser element 10 die-bonded on the heat sink 40 are measured. Note that the characteristics may be measured after cleaving or before die bonding.
[0039]
In this embodiment, when the nitride-based semiconductor laser device 10 is die-bonded on the heat sink 40, the emission end face 34 of the nitride-based semiconductor laser device 10 and the front surface 42 of the heat sink 40 are faced as shown in FIG. Match with one.
In the present embodiment, the emission end face 34 of the nitride semiconductor laser element 10 and the front face 42 of the heat sink 40 are flush with each other. However, this is not always necessary, and the nitride semiconductor laser element is not necessarily required. The ten emission end faces 34 may be set back from the front face 42 of the heat sink 40.
Next, the nitride-based semiconductor laser device 10 is irradiated with light, for example, laser light, with a lens, and the position of the through hole 32 is detected, and this is used as a positioning mark for the nitride-based semiconductor laser device 10. Then, the nitride-based semiconductor laser device 10 is positioned on the heat sink 40 so that the distance between the through hole 32 and the positioning mark 44 on the heat sink 40 is a predetermined distance.
[0040]
Embodiment 2
This embodiment is another example of the embodiment of the nitride-based compound semiconductor device mounting method according to the present invention, and FIG. 5 is a perspective view for explaining the positioning by applying the method of this embodiment. FIG.
The method of this embodiment is the same as that of Embodiment 1 except that the nitride-based semiconductor laser device 10 manufactured in the same manner as Embodiment 1 is die-bonded on the heat sink 40 via the submount 46. It is a configuration.
In this embodiment, when the nitride semiconductor laser element 10 is die-bonded on the heat sink 40 via the submount 46, the nitride semiconductor laser element 10 is submounted by the junction down method as shown in FIG. The emission end face 34 of the nitride-based semiconductor laser device 10, the front face 42 of the heat sink 40, and the front face 48 of the submount 46 are flush with each other.
[0041]
Next, the nitride-based semiconductor laser device 10 is irradiated with light, for example, laser light, with a lens, and the position of the through hole 32 is detected, and this is used as a positioning mark for the nitride-based semiconductor laser device 10. Then, the nitride-based semiconductor laser device 10 is positioned on the submount 46 so that the distance between the through hole 32 and the positioning mark 50 on the submount 46 is a predetermined distance.
[0042]
In the methods of the first and second embodiments, the through hole 32 provided in the high-density defect region generated at a precise position with good reproducibility is used as a positioning mark, thereby positioning the nitride semiconductor laser element 10 separately. The nitride-based semiconductor laser device 10 can be accurately positioned without providing a mark.
[0043]
Embodiment 3
This embodiment is another example of the embodiment of the nitride compound semiconductor device mounting method according to the present invention. FIG. 6 (a) shows a nitride-based application of the method of this embodiment. It is a perspective view explaining a mode that a semiconductor laser element is positioned, and FIG.6 (b) is a perspective view explaining the conventional positioning method.
The method of this embodiment is applied when the nitride semiconductor laser device 10 die-bonded on the heat sink 40 by the method of Embodiment 1 is mounted on the PDIC 52. Here, the PDIC is a photodiode integrated circuit.
When positioning the nitride semiconductor laser element 10 die-bonded on the heat sink 40 with respect to the photodiode 54 on the PDIC 52, as shown in FIG. For example, the position of the through hole 32 is detected by irradiating a laser beam with a lens.
Then, using the through hole 32 as a positioning mark, the nitride semiconductor laser element 10 is positioned with respect to the positioning mark 56 on the PDIC. The positioning mark 56 is provided at a predetermined position with respect to the photodiode 54 on the PDIC 52. In FIG. 6, 58 is a terminal.
[0044]
On the other hand, in the conventional method, in positioning the nitride semiconductor laser element 10 die-bonded on the heat sink 40 with respect to the photodiode 54 on the PDIC 52, as shown in FIG. The nitride-based semiconductor laser device 10 is positioned with respect to the photodiode 54 so that a predetermined distance is formed between the emission end face 34 of the device 10 and the positioning mark 56 on the PDIC.
[0045]
Nitride-based semiconductor laser elements have poor individual cleavage because they have poor cleaving properties, and therefore the output end face has poor linearity and cleavage reproducibility is poor. Therefore, in the conventional method using the emission end face 34 as a positioning reference, it is difficult to accurately position the nitride-based semiconductor laser device 10 with respect to the photodiode 54. However, in this embodiment, the position is high at an accurate position. Since the through hole 32 provided with reproducibility is used as a positioning reference, the nitride-based semiconductor laser device 10 can be accurately positioned with respect to the photodiode 54.
[0046]
In the above-described embodiment, the GaN substrate 76 in which the high-density defect regions are arranged in a square lattice shape is used as the GaN substrate. However, the present invention is not limited to this, and for example, as shown in FIG. A GaN substrate 92 in which density defect regions are arranged in a rectangular lattice shape, or a GaN substrate 94 in which high density defect regions are arranged in a hexagonal lattice shape as shown in FIG. 11C can be used.
Furthermore, as shown in FIGS. 12A and 12B, GaN substrates 96 and 98 in which high-density defect regions are linearly arranged can be used. 11 and 12 show the positional relationship between the high-density defect region and the laser stripe. In FIGS. 11 and 12, reference numeral 90 denotes a laser stripe.
[0047]
【The invention's effect】
According to the present invention, when a hole penetrating or not penetrating through the substrate in the core region having the highest defect density in the high-density defect region is provided, and when die-bonding to a heat sink, submount, package body, etc., a laser beam or the like By irradiating the nitride-based compound semiconductor element with the light and detecting the hole and using it as a positioning mark, the position of the nitride-based compound semiconductor element can be precisely controlled. Thereby, the yield of products can be improved and the cost can be reduced.
Similarly, when a nitride-based semiconductor laser device is mounted on a PDIC, precise position control of the nitride-based semiconductor laser device is possible, and the device characteristics of the integrated nitride-based semiconductor laser device are improved. Thereby, the yield of products can be improved and the cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a configuration of a GaN-based semiconductor laser device to which a method of Embodiment 1 is applied.
FIGS. 2A to 2C are cross-sectional views or perspective views for each step when die bonding of a GaN-based semiconductor laser device is performed by applying the method of Embodiment 1; FIG.
FIG. 3 is a flowchart illustrating a chip forming process and a mounting process.
4 is a perspective view for explaining the positioning of a nitride-based semiconductor laser device by applying the method of Embodiment 1; FIG.
5 is a perspective view for explaining the positioning of a nitride-based semiconductor laser device by applying the method of Embodiment 2; FIG.
6 (a) and 6 (b) show how a nitride-based semiconductor laser device is positioned with respect to a photodiode on a PDIC by applying the method of Embodiment 3 and the conventional method, respectively. FIG.
FIGS. 7A and 7B are perspective views showing a conventional method for positioning a nitride-based semiconductor laser device on a heat sink and a submount, respectively.
8A and 8B are a plan view and a cross-sectional view of a GaN substrate for explaining a high-density defect region, respectively.
FIGS. 9A and 9B are diagrams showing an array of rectangular lattices and an array of hexagonal lattices, respectively.
FIGS. 10A and 10B respectively show an arrangement in which dot-like high-density defect regions are arranged in a line in an intermittent manner, and a high-density defect region is arranged in a line in a continuous manner. FIG.
FIGS. 11 (a) to 11 (c) show sections of GaN-based semiconductor laser elements on GaN substrates in which high-density defect regions are arranged in a square lattice, a rectangular lattice, and a hexagonal lattice, respectively. FIG.
FIGS. 12A and 12B are diagrams showing sections of a GaN-based semiconductor laser device on a GaN substrate in which high-density defect regions are linearly arranged, respectively.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... GaN-type semiconductor laser element of Example 1, 12 ... n-type GaN substrate, 12a ... Core part, 14 ... n-type GaN layer, 16 ... n-type AlGaN clad layer, 18 ... n-type GaN optical waveguide layer, 20... Active layer having a multiple quantum well structure composed of Ga _1-x In _x N (well layer) and Ga _1-y In _y N (barrier layer), 22... P-type GaN optical waveguide 24... P-type AlGaN cladding layer 26... P-type GaN contact layer 28... P-side electrode 30... N-side electrode 32. , 42 ... front, 44 ... positioning mark, 46 ... submount, 48 ... front, 50 ... positioning mark, 52 ... PDIC, 54 ... photodiode, 56 ... positioning mark, 58 ... terminal 76 ... GaN substrate, 7 8: High-density defect region, 80: Semiconductor laser element, 82: Heat sink, 84: Positioning mark, 86: Submount, 88: Positioning mark, 90: Laser stripe, 92: High-density defect GaN substrate in which regions are arranged in a rectangular lattice, 94... GaN substrate in which high-density defect regions are arranged in a hexagonal lattice, 96, 98... GaN in which high-density defect regions are arranged in a line substrate.

Claims (7)

As a high crystal defect density than the surrounding area, to the semiconductor crystal substrate with a high density defective region extending through the substrate on the periodic substrate plane array, nitride comprising a nitride compound semiconductor multilayer structure A method of mounting a compound semiconductor device,
The penetrating highest core region defect density in the high density defective region or a hole so as to blind provided, then the semiconductor crystal forming the laminated structure on the substrate, chips and nitride system compound semiconductor after producing the element, when die bonding the nitride compound semiconductor device on a base,
The nitrided by the use of the nitride-based compound semiconductor device Upon positioning on the base, by irradiating light to the nitride-based compound semiconductor device detects the position of the hole, the hole as the positioning marks A method for mounting a nitride-based compound semiconductor element, comprising positioning a physical compound semiconductor element on the base. 2. The method for mounting a nitride-based compound semiconductor device according to claim 1, wherein the base for die-bonding the nitride-based compound semiconductor device is a submount or a heat sink. The nitride-based compound semiconductor element is a nitride semiconductor laser element, the base is a full photodiode integrated circuits having a light-receiving element on the surface,
The nitride semiconductor laser device Upon positioning the photodiode integrated circuit, by radiating light on the nitride-based semiconductor laser device to detect the position of the hole, using said holes as the positioning mark, mounting method for a nitride compound semiconductor device according to claim 1, characterized in that positioning the nitride semiconductor laser element to the light receiving element on the base. The high-density defect regions, mounting method for a nitride compound semiconductor device according to claim 1, characterized in that said are semiconductor periodically interspersed on the substrate surface of the crystal substrate. The high-density defect regions, the semiconductor crystal substrate of the substrate surface on a square grid pattern, rectangular grid pattern, and a hexagonal lattice as claimed in claim 1, characterized in that it is interspersed with either arrangement Method for mounting nitride compound semiconductor device. The high-density defect regions, according to claim 1, wherein the semiconductor crystal to each other to parallel spaced on the surface of the substrate, and is periodically disposed linear high density defective regions Mounting method for nitride-based compound semiconductor device . The linear high-density defect region is a linear high-density defect region in which dot-like high-density defect regions are in contact with each other or intermittently arranged in a line, or a high-density defect region is continuously linear. 7. The method for mounting a nitride-based compound semiconductor device according to claim 6, wherein the nitride-based compound semiconductor device is a high-density defect region extending in the region.

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