CN217426775U

CN217426775U - Fluorescent powder-free white light LED chip and composite substrate

Info

Publication number: CN217426775U
Application number: CN202220906036.6U
Authority: CN
Inventors: 王峰; 汪欢; 赵海琴; 陈素; 慈欣欣
Original assignee: Suzhou Ruiermei Photoelectric Technology Co ltd
Current assignee: Suzhou Ruiermei Photoelectric Technology Co ltd
Priority date: 2022-04-19
Filing date: 2022-04-19
Publication date: 2022-09-13
Anticipated expiration: 2032-04-19

Abstract

The utility model discloses a white light LED chip of no phosphor powder, which comprises a substrate, the substrate has first surface and second surface, the first surface is provided with graphical structure, the second surface is the polished surface the first surface of substrate is provided with LED epitaxial structure layer, the second surface bonding of substrate has first bonding base plate, and another surface bonding of first bonding base plate has second bonding base plate, obtains composite base plate, and first bonding base plate is the yellow alumina single crystal substrate of mixing nickel ion, and second bonding base plate is the red alumina single crystal substrate of mixing chromium ion. And exciting yellow light in the yellow aluminum oxide single crystal substrate and red light in the red aluminum oxide single crystal substrate by using blue light emitted from the epitaxial structure layer quantum well, so that the blue light, the yellow light and the red light are mixed to form low-color-temperature high-color-rendering-index white light. The process is effectively simplified, the process preparation time is shortened, the process cost is reduced, the LED energy conversion efficiency is improved, and the service life is prolonged.

Description

Fluorescent powder-free white light LED chip and composite substrate

Technical Field

The utility model belongs to the technical field of the LED chip, specifically relate to a white light LED chip and composite substrate of no phosphor powder.

Background

The current white light LED mainly adopts the following two structures:

one is to coat phosphor on the blue LED, that is, a part of blue light emitted by the blue LED is absorbed by the phosphor and emits yellow light, and the other part of blue light is mixed with the yellow light emitted by the phosphor, thereby obtaining white light. However, the white light LED mixed by the secondary quantum conversion using the phosphor has low luminous efficiency. Or the blue light LED chip is used for exciting the yellow light fluorescent powder to generate white light, the yellow light fluorescent powder and the silica gel are mixed together and packaged in the blue light LED chip to form a white light LED device, the yellow light fluorescent powder and the silica gel are in direct contact with the blue light LED chip which is heated after being electrified, so that the yellow light fluorescent powder and the silica gel are heated and aged in advance, and meanwhile, the thermal resistance of the blue light LED chip is increased due to the wrapping of the silica gel and the yellow light fluorescent powder, so that the heat dissipation of the blue light LED chip is not facilitated, and finally, the blue light LED chip is attenuated in advance.

The other is to laminate the LED chips of the three primary colors of red, green and blue together and light the LEDs of the three primary colors at the same time, thereby mixing the three primary colors of red, green and blue to obtain white light. The white light LED needs to laminate LED chips with three primary colors, so the preparation method of the white light LED with the structure is complex and has high cost.

Chinese patent document CN 104868027 a discloses a phosphor-free GaN-based white light LED epitaxial structure and a preparation method thereof, the epitaxial structure comprises a substrate, a GaN buffer layer, an N-GaN layer, a multiple quantum well layer with ultraviolet wavelength, a non-doped high-low temperature GaN layer, a multiple quantum well layer with blue wavelength and a P-GaN layer which are sequentially arranged from bottom to top. The yellow band of the non-doped high-low temperature GaN layer is excited by ultraviolet light to emit light, and the yellow band is superposed with blue light to obtain a GaN-based white light LED structure. However, in the method, the high-low temperature GaN layer is inserted between the ultraviolet light multi-quantum well layer and the blue light multi-quantum well layer, the process is complex, the realization difficulty is high, the growth time is long, and the cost of the epitaxial wafer is increased.

SUMMERY OF THE UTILITY MODEL

To the technical problem who exists above-mentioned, the utility model aims at: the blue light emitted from the quantum well of the epitaxial structure layer is used for exciting yellow light in the yellow aluminum oxide single crystal substrate and red light in the red aluminum oxide single crystal substrate, so that the blue light, the yellow light and the red light are mixed to form low-color-temperature high-color-rendering-index white light. The process is effectively simplified, the process preparation time is shortened, the process cost is reduced, the LED energy conversion efficiency is improved, the service life of the LED is prolonged, and the quality of emergent light, the light-emitting stability and the product repeatability are improved.

The technical scheme of the utility model is that:

the composite substrate comprises a substrate, wherein the substrate is provided with a first surface and a second surface, the first surface is provided with a graphical structure, the second surface is a polished surface, the first surface of the substrate is provided with an LED epitaxial structure layer, the second surface of the substrate is bonded with a first bonding substrate, the other surface of the first bonding substrate is bonded with a second bonding substrate to obtain the composite substrate, the first bonding substrate is a yellow aluminum oxide single crystal substrate doped with nickel ions, and the second bonding substrate is a red aluminum oxide single crystal substrate doped with chromium ions.

In a preferred technical scheme, the LED epitaxial structure layer comprises a buffer layer, an N-type GaN semiconductor structure layer and a P-type GaN semiconductor structure layer which are epitaxially grown in sequence.

In a preferred technical scheme, the substrate is a sapphire substrate.

In the preferred technical scheme, the thickness of the substrate is 100-200 um, the BOW is controlled within +/-5 um, and the Warp Warp is less than or equal to 10 um.

In an optimized technical scheme, the first surface and the second surface of the first bonding substrate and the second bonding substrate are polished surfaces, the thickness is 100-200 um, the BOW BOW is controlled within +/-5 um, and the Warp Warp is less than or equal to 10 um.

In a preferred technical solution, the first bonding substrate and the second bonding substrate are bonded by using a high refractive index bonding agent.

In a preferred technical scheme, the bonding agent is one of epoxy resin, silica gel or a mixture of the epoxy resin and the silica gel.

The invention also discloses a white light LED chip without fluorescent powder, which comprises the composite substrate, wherein the LED epitaxial structure layer of the composite substrate is provided with a P-type electrode and an N-type electrode.

In a preferred technical scheme, the P-type electrode and the N-type electrode are flip-chip mounted on the heat dissipation substrate in a eutectic bonding manner, and the heat dissipation substrate is provided with a positive electrode and a negative electrode which are respectively in one-to-one correspondence with the P-type electrode and the N-type electrode.

In a preferred technical solution, the positive electrode and the negative electrode of the heat dissipation substrate are further provided with lead bonding areas for external leads of the flip chip, and the heat dissipation substrate is one of a ceramic substrate, an aluminum substrate, a silicon substrate, or a copper substrate with an insulating layer coated on the surface.

Compared with the prior art, the utility model has the advantages that:

1. the white light LED chip bonds a patterned sapphire substrate growing over the LED epitaxy, a yellow aluminum oxide single crystal substrate doped with nickel ions (Ni3+) and a red aluminum oxide single crystal substrate doped with chromium ions (Cr3+) to form a composite substrate, and the color temperature and the color rendering index of the white light LED can be adjusted by adjusting the doping concentrations of the nickel ions (Ni3+) and the chromium ions (Cr3+) in the aluminum oxide single crystal.

2. And a back light emitting mode is adopted to excite yellow light in the yellow aluminum oxide single crystal substrate and red light in the red aluminum oxide single crystal substrate by using blue light emitted from the epitaxial structure layer quantum well, so that the blue light, the yellow light and the red light are mixed to form low-color-temperature high-color-rendering-index white light. The process is effectively simplified, the process preparation time is shortened, the process cost is reduced, the LED energy conversion efficiency is improved, the service life of the LED is prolonged, and the quality of emergent light, the light-emitting stability and the product repeatability are improved. The white light LED chip does not need to be added with fluorescent powder, avoids the aging problem of the fluorescent powder, is suitable for large-scale batch production, and can be widely applied to the field of semiconductor solid illumination.

Drawings

The invention will be further described with reference to the following drawings and examples:

fig. 1 is a schematic structural diagram of a composite substrate for manufacturing a phosphor-free white LED chip according to the present invention;

fig. 2 is a schematic structural diagram of the fluorescent powder-free white light LED chip of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in detail with reference to the accompanying drawings. It should be understood that the description is intended to be illustrative only and is not intended to limit the scope of the present invention. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present invention.

Example (b):

as shown in fig. 1, a composite substrate for manufacturing a phosphor-free white LED chip includes a substrate 1, the substrate 1 has a first surface and a second surface, the first surface is provided with a patterned structure 2, the second surface 8 is a polished surface, the patterned structure 2 on the first surface of the substrate 1 is provided with an LED epitaxial structure layer, the second surface 8 of the substrate 1 is bonded with a first bonded substrate 6, the other surface of the first bonded substrate 6 is bonded with a second bonded substrate 7, so as to obtain the composite substrate 100, the first bonded substrate 6 is a nickel-doped ion (Ni ion) (Ni-doped substrate 6) ³⁺ ) The second bonding substrate is a chromium ion (Cr) doped substrate ³⁺ ) The red alumina single crystal substrate of (1).

Can adjust nickel ion (Ni) in the alumina single crystal ³⁺ ) And chromium ion (Cr) ³⁺ ) The color temperature and the color rendering index of the white light LED are adjusted.

Preferably, the substrate 1 is a sapphire substrate, but may be silicon (Si), silicon carbide (SiC), or the like.

In a preferred embodiment, the LED epitaxial structure layer includes a buffer layer 3, an N-type GaN semiconductor structure layer 4 and a P-type GaN semiconductor structure layer 5 which are epitaxially grown in sequence. The method of epitaxial growth is a Metal Organic Chemical Vapor Deposition (MOCVD) method.

In a preferred embodiment, the back surface 8 of the polished surface of the sapphire substrate 1 is subjected to back surface thinning polishing after the growth of the LED epitaxial structure is completed, the surface roughness of the back surface 8 of the polished surface after thinning polishing is less than or equal to 0.3nm, the diameter of the sapphire substrate 1 is 2-6 inches, the thickness of the sapphire substrate 1 after thinning polishing is controlled to be 100-200 um, the total thickness variation TTV is less than or equal to 5um, the BOW is controlled to be within ± 5um, and the Warp is less than or equal to 10 um.

In a preferred embodiment, the first surface and the second surface of the first bonding substrate 6 are polished surfaces, the surface roughness of the two surfaces after double-side polishing is less than or equal to 0.3nm, the diameter of the first bonding substrate 6 is equivalent to that of the sapphire substrate 1 and is also 2-6 inches, the thickness of the first bonding substrate 6 after double-side polishing is controlled within 100-200 um, the total thickness variation TTV is less than or equal to 5um, the BOW BOW is controlled within +/-5 um, and the warping degree Warp is less than or equal to 10 um.

The first surface and the second surface of the second bonding substrate 7 are polished surfaces, the surface roughness of the two surfaces after double-side polishing is less than or equal to 0.3nm, the diameter of the second bonding substrate 7 is equivalent to that of the sapphire substrate 1 and is also 2-6 inches, the thickness of the second bonding substrate after double-side polishing is controlled to be 100-200 um, the total thickness variation TTV is less than or equal to 5um, the bending BOW is controlled to be +/-5 um, and the warping degree Warp is less than or equal to 10 um.

And bonding the back surface 8 of the sapphire substrate which grows beyond the LED epitaxy and has the back surface thinned and polished and the first polished surface 9 of the first bonding substrate together in sequence by using a bonding process, and bonding the second polished surface 10 of the first bonding substrate and the first polished surface 11 of the second bonding substrate together to form the composite substrate 100.

Preferably, the bonding is performed by using a bonding agent 13, and the bonding agent 13 is epoxy resin, silica gel or a mixture of the epoxy resin and the silica gel with high refractive index, i.e. the refractive index is greater than or equal to 1.5.

The bonding process is carried out in a vacuum environment, the process vacuum degree is 5-10 mbar, the bonding adopts a hot-pressing UV rapid curing mode, the substrate to be bonded is heated to 100-150 ℃, the bonding agent 13 is coated on the bonding surface of the substrate, the substrates are bonded together through pressurization, the applied pressure is 0.1-0.5 kg/square centimeter, then the bonding agent 13 is rapidly cured through UV light irradiation, the bonding agent 13 is sensitive to UV light, the wavelength range of the UV light is 365-385 nm, and the irradiation time of the UV light is 5-10 seconds.

As shown in fig. 2, the invention also discloses a phosphor-free white LED chip, which includes the above composite substrate 100, and the LED epitaxial structure layer of the composite substrate 100 is provided with a P-type electrode 14 and an N-type electrode 15.

The electrode formation surface of the composite substrate 100 is the epitaxial growth surface of the sapphire substrate 1. The P-type electrode 14 and the N-type electrode 15 can be prepared on the electrode preparation surface of the composite substrate by using the semiconductor chip processing technologies such as photolithography, development, etching, sputtering, evaporation, coating and the like.

The material of the P-type electrode 14 and the N-type electrode 15 is one or more of chromium, platinum, gold, nickel, titanium, copper, indium, tin, lead and silver.

And finally, cutting the composite substrate into independent LED chips by laser scribing. The LED lamp can be suitable for large-scale batch production, greatly reduces the manufacturing cost, and can be widely applied to the field of semiconductor solid illumination.

In a preferred embodiment, the P-type electrode 14 and the N-type electrode 15 of the LED chip are flip-chip mounted on the heat dissipation substrate 21 by eutectic bonding, the heat dissipation substrate 21 is provided with a positive electrode 17 and a negative electrode 18, the positive electrode 17 and the negative electrode 18 of the heat dissipation substrate 21 respectively correspond to the P-type electrode 14 and the N-type electrode 15 of the white LED chip, and the positive electrode 17 and the negative electrode 18 of the heat dissipation substrate 21 are further provided with lead bonding pads 19 for external leads of the chip.

The heat dissipation substrate 21 is one of ceramic substrates, aluminum substrates, silicon substrates, copper substrates, and other plates with excellent heat dissipation function, the surfaces of which are coated with the insulation layer 20.

The blue light emitted from the quantum well of the epitaxial structure layer is used for exciting the yellow light in the yellow aluminum oxide single crystal substrate and the red light in the red aluminum oxide single crystal substrate in a back light emitting mode, so that the blue light, the yellow light and the red light are mixed to form the white light with low color temperature and high color rendering index.

It should be understood that the above-described embodiments of the present invention are merely illustrative of or explaining the principles of the invention and are not to be construed as limiting the invention. Therefore, any modification, equivalent replacement, improvement and the like made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. Further, it is intended that the appended claims cover all such variations and modifications as fall within the scope and boundaries of the appended claims or the equivalents of such scope and boundaries.

Claims

1. The composite substrate for manufacturing the fluorescent powder-free white light LED chip comprises a substrate, wherein the substrate is provided with a first surface and a second surface, the first surface is provided with a graphical structure, and the second surface is a polished surface.

2. The composite substrate for manufacturing a phosphor-free white light LED chip according to claim 1, wherein the LED epitaxial structure layer comprises a buffer layer, an N-type GaN semiconductor structure layer and a P-type GaN semiconductor structure layer which are epitaxially grown in sequence.

3. The composite base plate for manufacturing a phosphor-free white LED chip according to claim 1, wherein the substrate is a sapphire substrate.

4. The composite substrate for manufacturing a phosphor-free white LED chip according to claim 1, wherein the thickness of the substrate is 100-200 um, the BOW BOW is controlled within +/-5 um, and the Warp Warp is less than or equal to 10 um.

5. The composite substrate for manufacturing a phosphor-free white LED chip according to claim 1, wherein the first and second surfaces of the first and second bonded substrates are polished surfaces with a thickness of 100-200 um, a BOW BOW is controlled within ± 5um, and a Warp Warp is less than or equal to 10 um.

6. The composite substrate for making a phosphor-free white LED chip according to claim 1, wherein the first and second bonding substrates are bonded using a high refractive index bonding agent.

7. The composite substrate for making a phosphor-free white LED chip according to claim 6, wherein the bonding agent is one of epoxy, silica gel or a mixture thereof.

8. A phosphor-free white light LED chip, characterized by comprising the composite substrate of any one of claims 1 to 7, wherein the LED epitaxial structure layer of the composite substrate is provided with a P-type electrode and an N-type electrode.

9. The phosphor-free white LED chip of claim 8, wherein the P-type electrode and the N-type electrode are flip-chip bonded by eutectic bonding on a heat sink substrate, the heat sink substrate being provided with a positive electrode and a negative electrode, the positive electrode and the negative electrode corresponding to the P-type electrode and the N-type electrode one-to-one, respectively.

10. The phosphor-free white LED chip of claim 9, wherein the positive and negative electrodes of the heat dissipating substrate are further provided with wire bonding pads for external leads of a flip chip, the heat dissipating substrate being one of a ceramic substrate, an aluminum substrate, a silicon substrate, or a copper substrate with an insulating layer coated on a surface thereof.