WO2017206331A1

WO2017206331A1 - Led package substrate and preparation method therefor

Info

Publication number: WO2017206331A1
Application number: PCT/CN2016/094070
Authority: WO
Inventors: 赵龙
Original assignee: 深圳朝伟达科技有限公司
Priority date: 2016-06-02
Filing date: 2016-08-09
Publication date: 2017-12-07
Also published as: CN105914288A

Abstract

An LED package substrate and a preparation method therefor. The LED package substrate comprises: a package substrate (101) used for protecting and bearing an LED chip; a reflective layer (107, 108) located on the package substrate (101); a light conversion layer (109) located on the reflective layer (107, 108); a package substrate-free LED chip located on the light conversion layer (109), said chip being capable of bidirectionally emitting light having a specific wavelength. The package substrate includes the light conversion layer (109), thereby simplifying a package process. The preparation process is advantageous for the large-batch preparation of package substrates containing a uniform fluorescent powder, and increases product yield and production.

Description

LED package substrate and preparation method thereof

Technical field

The present invention relates to a light emitting diode based package substrate and a method of fabricating the same, and more particularly to a package substrate including a light conversion material.

Background technique

Solid-state lighting, especially light-emitting diodes (LEDs), is becoming a new generation of light sources because of its long life, no pollution, and high luminous efficiency. Since the LEDs produced by direct production are monochromatic light, in order to obtain white light, a plurality of colors must be mixed to form. The most common way to prepare a white LED is to use a blue/ultraviolet LED to excite the light conversion material, and the light emitted by the LED itself and the complementary light converted by the light conversion layer together form white light.

The preparation process of the existing LED package is as follows: an LED package substrate is provided, the LED chip is fixed on the package substrate, and after the wire is applied, the phosphor is coated on the chip and then baked. After the blue light emitted from the LED chip passes through the phosphor layer, it is partially absorbed by the phosphor and converted into yellow light, which is mixed with the blue light to form white light.

The most critical step in the packaging process is to coat the phosphor, and the prior art, whether dispensing or dusting, has its insurmountable shortcomings. The dispensing method is to use a dispenser to dispense the fluorescent glue on the package substrate of the LED chip. Due to the fluctuations (pressure, voltage, etc.) of the dispenser machine, the glue on each LED chip is not the same. At the same time, due to the sedimentation of the phosphor, the concentration of the phosphor contained on each LED chip is also different. These two points eventually caused the difference in color point of the white LED chips manufactured in the same batch, which caused a bad. In addition, dispensing machines are slower to dispense and have limited capacity in high volume manufacturing. Although the method of powder coating phosphor is improved in terms of color point uniformity, since the area of the powder is large each time, the edge of the sample to be sprayed causes a great waste. At the same time, the dusting equipment is expensive, and the cost per package is high.

Summary of the invention

The purpose of the invention is to simplify the LED packaging process and improve the shortcomings of the existing phosphor coating method, mainly through the system. When the substrate is packaged, the phosphor is prepared on the substrate, so that the package only needs to complete the die bonding and wire bonding process.

To achieve this object, the present invention provides a susceptor for carrying the rest of the package substrate; a reflective reflective layer on the pedestal for reflecting light emitted by the LED chip and emitted by the phosphor a light conversion layer prepared on the reflective layer for absorbing blue light emitted from the LED chip toward the package substrate and converting into yellow light. The blue light emitted by the chip upward and the yellow light reflected by the reflective layer are mixed together to form white light.

In one embodiment, the susceptor is a ceramic pedestal on which a circuit is pre-arranged for subsequent use with the LED chip; then a reflective material is plated on the surface of the ceramic pedestal for use as a reflective layer . Wherein, a conductive material such as silver or the like is plated on the susceptor circuit. The other part is coated with an insulating material, such as DBR; finally, the ceramic phosphor sheet is aligned and bonded to the ceramic base, and is sintered at 500 ° C - 1000 ° C; wherein the ceramic phosphor sheet is pre-drilled The hole is filled with a conductive material in the through hole.

In one embodiment, a ceramic phosphor sheet is first provided, a through hole is drilled thereon, and a conductive material is filled in the through hole; and a partition bar is formed on the back surface of the ceramic phosphor sheet with an insulating material to separate the positive a negative electrode through hole; a conductive reflective material is plated on the back surface of the ceramic phosphor sheet as a reflective layer, such as silver; and a thick (more than 100 micrometer) conductive layer is plated under the reflective layer on the back surface of the ceramic phosphor sheet. It is used to protect the supporting phosphor sheet and the reflective layer and function as a pedestal. The manufacturing method is characterized in that the conductive light-reflecting layer and the thick conductive layer are all spaced apart in the positive and negative electrode through holes by the partition bar.

In one embodiment, a susceptor is provided on which the grooves, circuitry and solder bumps are pre-arranged. A recess is used to place the phosphor layer; circuitry and solder bumps are used to form an electrical connection with the LED chip; a reflective material is applied to the surface of the base as a reflective layer. A conductive material such as silver or the like is plated on the susceptor circuit. The remaining part is plated with an insulating material, such as DBR, etc.; the surface of the base is coated with a fluorescent glue, and baked at 100 ° C - 500 ° C; grinding / cutting flatten the surface of the fluorescent glue to expose the solder bumps.

While the invention will be described in conjunction with the exemplary embodiments and the methods of the invention, it is understood that the invention is not intended to limit the invention. Rather, the invention is to cover all alternatives, modifications, and equivalents of the scope of the invention as defined by the appended claims.

DRAWINGS

The drawings are intended to provide a further understanding of the invention, and are intended to be a In addition, the drawing figures are a summary of the description and are not drawn to scale.

1 is a schematic cross-sectional view of Embodiment 1.

2 is a flow chart of the preparation of Example 1.

3 is a schematic cross-sectional view of Embodiment 2.

4 is a flow chart of the preparation of Example 2.

Fig. 5 is a schematic cross-sectional view showing the third embodiment.

Figure 6 is a flow chart showing the preparation of Example 3.

The numbers in the figure indicate:

101 ceramic base

102 ceramic body

103 ceramic base circuit

104 ceramic base circuit

105 ceramic base internal through hole conductive column

106 insulation block

107, 207 Ag reflective layer

108, 208 DBR reflective layer

109,209 ceramic phosphor film

Through-hole conductive column inside 110,210 ceramic phosphor sheet

212 conductive base

301 base

302 insulated base body

303 circuit

304 solder bump

305 white reflective paint

306 fluorescent glue

307 groove

detailed description

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings and embodiments, in which the present invention can be applied to the technical problems, and the implementation of the technical effects can be fully understood and implemented. It should be noted that the various embodiments of the present invention and the various features of the various embodiments may be combined with each other, and the technical solutions formed are all within the scope of the present invention.

Example 1:

A schematic cross-sectional view of a single package substrate of Example 1 prepared and cut is shown in FIG. The preparation process is as shown in FIG. 2, and a ceramic base 101 prepared in advance is first provided. The ceramic pedestal comprises a ceramic body 102, a lower surface circuit 103, an upper surface circuit 104, and a via-conducting post 105 inside the ceramic pedestal connecting the upper and lower surface circuits, wherein the circuits of the same surface are separated by an insulating block 106; The material of the seat may be alumina, aluminum nitride or the like, and preferably, the base is made of alumina. The material of the upper and lower surfaces and the through-hole conductive pillars may be one or an alloy of copper, silver and gold. Preferably, copper is used as the conductive material. The material used for the insulating block 106 is alumina.

Then, the surface of the ceramic base is plated with a reflective layer, and the upper surface circuit 104 is plated with a conductive reflective material, preferably silver plated 107; an insulating material is plated on the insulating block 106, preferably, DBR is plated. . The embodiment S11 can be: 1) first plating the DBR on the whole surface; 2) using the photoresist to open the pattern on the DBR, the upper part of the insulating block is blocked by the photoresist, and the electricity is blocked. The road position is exposed; 3) etching the exposed DBR layer; 4) depositing the Ag layer. 5) Remove the photoresist. The DBR material is a combination of silicon oxide and titanium oxide.

Finally, as shown in S12, a pre-prepared ceramic phosphor sheet 109 is provided which contains via-hole conductive posts 110 therein. The ceramic phosphor sheet 109 is aligned and bonded to the ceramic base 101, and is sintered at 500 ° C - 1000 ° C, preferably at 850 ° C.

The package substrate of the invention is integrally formed by a susceptor and a ceramic phosphor powder sheet, and the components are combined well, the structural strength is higher, and the electrical and thermal conductivity properties are better. At the same time, the phosphor coating method of the invention does not need to be coated on different package brackets separately, which reduces the problem of large difference in color point of the conventional dispensing method, and is more suitable for mass production and production. Finally, the blue light emitted by the LED back is within twice the thickness of the phosphor sheet. Therefore, it is possible to convert more yellow light with a thinner phosphor.

Example 2:

A schematic cross-sectional view of a single package substrate of Example 2 prepared and cut is shown in FIG. The preparation process is as shown in FIG. 4, and a pre-prepared ceramic phosphor sheet 209 is provided, which internally contains a via-hole conductive pillar 210.

Then, as shown in S21, a partition 208 is formed of an insulating material on the back surface of the ceramic phosphor sheet 209 to partition the positive and negative electrode through holes. Preferably, we here select a plated insulated DBR, such as a combination of silicon oxide and titanium oxide. The implementation method is as follows: 1) firstly plating the DBR on the whole surface; 2) using the photoresist to open the pattern on the DBR, the insulating area is blocked by the photoresist, and the conductive position is exposed; 3) etching the exposed DBR Floor;

Then, as shown in S22, an Ag layer is further deposited as a reflective layer on the back side of the ceramic phosphor sheet under the condition that the photoresist in the step S21 is left.

Finally, as shown in S23, a thick (over 100 μm) conductive layer is further deposited on the back side of the ceramic phosphor sheet under the condition of retaining the photoresist in the step S21 for protecting the supporting phosphor sheet and the reflective layer. , plays the role of the pedestal. The material of the conductive layer is copper silver gold or an alloy thereof. Preferably, the total thickness of the conductive layer and the Ag light reflecting layer is greater than the thickness of the DBR layer.

This embodiment is a simplified version of Embodiment 1, which is more advantageous in cost due to the saving of the ceramic base.

Example 3:

A schematic cross-sectional view of a single package substrate of Example 3 prepared and cut is shown in FIG. The preparation process is as shown in FIG. 6, and a susceptor 301 is provided on which the groove 307, the circuit 303 and the solder bump 304 are arranged in advance. Preferably, the material of the pedestal is selected from engineering plastics such as PPA, EMC, etc.; the circuit and the solder bumps are selected from copper.

Then, as shown in S31, a reflective paint is selectively applied to the surface of the susceptor 301 as a reflective layer. The reflective varnish is applied to the surface of the pedestal except the solder bump.

Then, as shown in S32, the surface of the susceptor 301 is coated with a fluorescent gel 306, which is baked in an oven at 150 ° C for four hours.

Finally, the polishing/cutting flattens the surface of the phosphor to expose the solder bumps.

Claims

An LED package substrate comprising: a pedestal for carrying a remaining portion of the package substrate; a reflective layer on the pedestal; a light conversion layer on the reflective layer; the pedestal is made of plastic or metal One or more combinations of ceramics; the pedestal further comprising a thermally conductive and electrically conductive passage for communicating the LED chip and the external environment; the reflective layer being composed of one or more of a metal mirror, a photonic crystal, and a reflective coating The light conversion material of the light conversion layer is composed of one or more of a phosphor, a quantum dot, and an organic fluorescent/phosphorescent material, wherein the thickness of the light conversion layer is less than 1 mm.
A method for preparing an LED package substrate according to claim 1, characterized in that:

1) providing a ceramic pedestal on which a circuit is pre-arranged for conducting with the LED chip;

2) A reflective material is plated on the surface of the ceramic base as a reflective layer. A conductive material such as silver or the like is plated on the susceptor circuit. Insulate the rest of the material, such as DBR;

3) aligning the ceramic phosphor sheet to the ceramic base, and sintering at 500 ° C - 1000 ° C; wherein the ceramic phosphor sheet is pre-drilled through the through hole, and the conductive material is filled in the through hole .