CN103855293B - Led - Google Patents

Abstract

The present invention is applicable to the field of semiconductor technology, and provides an LED, which includes a first etched metal sheet and a second etched metal sheet used as positive and negative electrodes of the LED, and the positive and negative electrodes are respectively welded to the first etched metal sheet An LED flip-chip chip with a second metal etching sheet, the LED flip-chip chip is covered by fluorescent glue, the fluorescent glue is covered by transparent encapsulation glue, the first metal etching sheet and the second metal etching sheet are close to each other The two sides form a "convex" shaped through groove. In this way, there is a transition between the electrode of the LED flip-chip chip and the welding electrode on the application side, which is used as the positive and negative electrodes of the LED, so that the use of this LED product on the application side will not increase the difficulty, which is completely equivalent to the use of injection molded brackets. And because the LED does not have the bracket required by conventional LED packaging, it has extremely high reliability. In addition, the packaging cost of the LED is extremely low.

Description

led

technical field

The invention belongs to the field of semiconductors, in particular to an LED.

Background technique

The packaging method of white light LED products is to fix the LED chip on the bracket by bonding or eutectic welding, use gold wires to connect the positive pole of the chip to the positive pole of the bracket, and connect the negative pole of the chip to the negative pole of the bracket, and then Fill with phosphors that match the target color zone. Due to the different thermal expansion coefficients of brackets and wafer colloids, reliability problems are prone to occur in brackets, die-bonding glue, gold wires, colloids, etc., and there are many types of LED brackets. The materials for bonding the positive and negative electrodes of the bracket are PPA, PCT, and EMC. , in terms of high temperature resistance and air tightness, there are relatively large defects, which affect the reliability of LED products; ceramic brackets have better high temperature resistance and better air tightness, but the cost of the bracket is close to the chip cost, and the package LED manufacturing costs are expensive, equipment investment is large, and production capacity is small. In short, the reliability, service life and product price of LED lighting products with bracket package structure are the biggest obstacles for LED lighting products to replace traditional lighting.

Contents of the invention

The purpose of the embodiments of the present invention is to provide an LED with high reliability.

The embodiment of the present invention is achieved in this way, an LED, including a first metal etching sheet and a second metal etching sheet used as the positive and negative electrodes of the LED, and the positive and negative electrodes are welded to the first metal etching sheet and the second metal etching sheet respectively. An etched LED flip chip, the LED flip chip is covered by fluorescent glue, the fluorescent glue is covered by transparent encapsulation glue, the two sides of the first metal etched sheet and the second metal etched sheet that are close to each other form a " Convex-shaped through-groove, the transparent packaging glue is filled in the upper part of the "convex"-shaped through-groove, the lower part of the "convex"-shaped through-groove is filled with solder resist material, the "convex"-shaped through-groove The upper part is etched prior to the lower part of the "convex" shaped through groove.

In the embodiment of the present invention, the first etched metal sheet and the second etched metal sheet are used as the positive and negative poles of the LED respectively, and the positive and negative poles of the LED flip chip are soldered to the first etched metal sheet and the etched metal sheet respectively. , so that there is a transition between the electrode of the LED flip-chip chip and the welding electrode on the application side, which is used as the positive and negative electrodes of the LED, so that the use of this LED product on the application side will not increase the difficulty, which is completely equivalent to the use of the injection molding bracket. . And because the LED does not have the bracket required by conventional LED packaging, it has extremely high reliability. In addition, the packaging cost of the LED is extremely low.

Description of drawings

Figure 1 is a schematic structural view of an LED provided by an embodiment of the present invention (the transparent encapsulant is only filled in the upper part of the "convex" shaped through groove);

Fig. 2 is a schematic structural view of the LED provided by the embodiment of the present invention (the transparent encapsulant is filled in the upper part of the "convex" shaped through groove, and the lower part of the "convex" shaped through groove is filled with solder resist material);

Fig. 3 is a schematic structural view of the LED provided by the embodiment of the present invention (transparent encapsulant is filled in the entire "convex" shaped through groove);

Fig. 4 is a flow chart of realizing the LED packaging method provided by the first embodiment of the present invention;

Fig. 5 is a structural schematic diagram of etching the first half-etched groove out of the metal etching sheet;

Fig. 6 is a schematic structural diagram of an LED flip chip;

Fig. 7 is a structural schematic diagram of LED flip-chip chip eutectic soldering on both sides of the first half etching groove;

Fig. 8 is a schematic structural view of coating fluorescent glue on the surface of the LED flip chip shown in Fig. 7;

FIG. 9 is a structural schematic diagram of etching grooves for standardizing fluorescent glue around the area where the LED flip chip is fixed;

Fig. 10 is a schematic structural view of coating fluorescent glue on the surface of the LED flip chip shown in Fig. 9;

Fig. 11 is a schematic structural view (sectional view) of laying transparent encapsulant on the etched metal sheet shown in Fig. 8;

Fig. 12 is a schematic structural view (top view) of laying transparent encapsulant on the etched metal sheet shown in Fig. 8;

Fig. 13 is a schematic structural view of etching a second half-etched groove at the bottom of the metal etching sheet;

Fig. 14 is a schematic diagram of the structure of each LED cut out from the semi-finished product shown in Fig. 13;

Fig. 15 is a schematic structural view of filling the solder resist material in the second half-etched groove shown in Fig. 13;

Fig. 16 is a schematic structural diagram of cutting out each LED from the semi-finished product shown in Fig. 15;

Fig. 17 is a flow chart of realizing the LED packaging method provided by the second embodiment of the present invention;

Fig. 18 is a structural schematic diagram of an etching groove etched out of a metal etching sheet;

Fig. 19 is a schematic structural diagram of an LED flip chip;

Fig. 20 is a structural schematic diagram of the electrode eutectic welding of the LED flip-chip chip on both sides of the upper part of the etching groove;

Figure 21 is a top view of Figure 20;

FIG. 22 is a schematic structural view of coating fluorescent glue on the surface of the LED flip chip shown in FIGS. 20 and 21;

Figure 23 is a top view of Figure 22;

FIG. 24 is a structural schematic diagram of etching grooves for standardizing fluorescent glue around the area where the LED flip-chip is fixed;

Fig. 25 is a schematic structural view of coating fluorescent glue on the surface of the LED flip chip shown in Fig. 24;

Fig. 26 is a schematic structural view of sticking an adhesive tape on the lower surface of the metal etching sheet shown in Fig. 22;

Fig. 27 is a schematic structural view of laying transparent encapsulant on the etched metal sheet shown in Fig. 26;

Figure 28 is a top view of Figure 27;

Fig. 29 is a schematic diagram of the structure after the transparent encapsulant is cured and the adhesive tape is removed;

Fig. 30 is a structural schematic diagram when cutting the semi-finished product shown in Fig. 29;

Figure 31 cuts out the structural schematic diagram of each LED;

FIG. 32 is a top view of FIG. 31 .

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

In the embodiment of the present invention, the first etched metal sheet and the second etched metal sheet are respectively used as the positive and negative poles of the LED, and the positive and negative poles of the LED flip chip are welded to the first etched metal sheet and the etched metal sheet respectively. , so that there is a transition between the electrode of the LED flip-chip chip and the welding electrode on the application side, which is used as the positive and negative electrodes of the LED, so that the use of this LED product on the application side will not increase the difficulty, which is completely equivalent to the use of the injection molding bracket. . And because the LED does not have the bracket required by conventional LED packaging, it has extremely high reliability. In addition, the packaging cost of the LED is extremely low.

The implementation of the present invention will be described in detail below in conjunction with specific embodiments.

As shown in Figures 1 to 3, the LED provided by the embodiment of the present invention includes a first etched metal sheet 11 and a second etched metal sheet 12 used as positive and negative electrodes of the LED, and the positive and negative electrodes are welded to the first etched metal sheet respectively. 11 and the LED flip chip 3 of the second metal etching sheet 12, the LED flip chip 3 is covered by the fluorescent glue 4, the fluorescent glue 4 is covered by the transparent encapsulation glue 7, the first metal etching sheet 11 and the second metal etching sheet The two side surfaces of the two metal etching pieces 12 close to each other form a "convex" shaped through groove. In this way, there is a transition between the electrode of the LED flip-chip chip 3 and the welding electrode of the application end, which are used as LED positive and negative electrodes. How to use the bracket. And because the LED does not have the bracket required by conventional LED packaging, it has extremely high reliability. In addition, the packaging cost of the LED is extremely low.

As an embodiment of the present invention, the transparent encapsulant 7 is simultaneously filled in the upper part of the “convex” through-groove, as shown in FIG. 1 . As a preference, the lower part of the "convex" through-groove is filled with solder resist material 10, which helps the bonding between the positive and negative metal etched sheets of the LED 8 and improves the reliability of the entire LED 8; secondly, it ensures the application terminal solder paste will not short circuit, as shown in Figure 2.

As another embodiment of the present invention, the transparent encapsulant 7 is filled in the entire “convex” through groove, as shown in FIG. 3 . It also contributes to the bonding between the positive and negative metal etching sheets of the LED 8 and improves the reliability of the entire LED 8; secondly, it ensures that the solder paste at the application end will not be short-circuited.

Fig. 4 shows the implementation process of the LED packaging method provided by the first embodiment of the present invention, which is described in detail as follows.

In step S401, a plurality of parallel first half-etched grooves are etched on the metal etching sheet.

In the embodiment of the present invention, a plurality of parallel first half-etched grooves 2 are etched on the upper part of the metal etching sheet 1. The width of the first half-etched grooves 2 is equal to the shortest distance between the positive and negative electrodes of the LED flip-chip chip 3, which is convenient for subsequent processes. The LED flip chip 3 is welded, and the depth of the first half-etched groove 2 is slightly greater than the shortest distance between the positive and negative electrodes of the LED flip chip 3 , as shown in FIGS. 5 and 6 . Wherein, the thickness of the metal etching sheet 1 is preferably 0.1-0.3 mm. Because the size of the manufactured LED product is determined by the size of the positive and negative electrodes of the etched sheet, it is easy to make a packaged product of the etched sheet bracket with the same size as the conventional LED packaged product.

In step S402, the positive and negative electrodes of the LED flip chip are welded to both sides of the first half-etched groove respectively.

In the embodiment of the present invention, a plurality of LED flip-chip chips 3 are obtained first, and then the positive and negative electrodes of each LED flip-chip chip 3 are eutectically soldered to both sides of the first half-etched groove 2 , as shown in FIG. 7 . It should be noted that the positive and negative electrodes of the LED flip chip 3 are located at the bottom thereof, one of which is a positive electrode and the other is a negative electrode.

In step S403 , coating the fluorescent glue covering the LED flip chip on the metal etching sheet and curing it.

In the embodiment of the present invention, the fluorescent glue 4 covering the LED chip-on-chip 3 is coated on the metal etching sheet 1 and cured, as shown in FIGS. 8-10 . Specifically, the applicant can adopt the method of coating fluorescent glue on the surface of the LED flip chip disclosed in the patent application document with the document number CN102544260A. If grooves 6 are used to standardize the fluorescent glue 4 , when etching the first half-etched groove 2 , grooves 6 are etched around the area where the LED flip chip 3 is fixed, as shown in FIG. 9 . Wherein, the thickness of the fluorescent glue 4 is preferably 0.03-0.5 mm. Because the fluorescent glue 4 has a certain viscosity and surface tension, it will not flow out along the first half-etched groove 2 .

In step S404, a transparent encapsulation glue covering the fluorescent glue is formed on the metal etching sheet and cured.

In the embodiment of the present invention, a transparent packaging glue (such as transparent silica gel) 7 covering the fluorescent glue 4 is molded on the metal etching sheet 1 and cured, as shown in FIGS. 11 and 12 . Wherein, the transparent encapsulant 7 is also filled in the first half-etched groove 2 . In order to enhance the light spot uniformity of LED products, a certain proportion of silicon dioxide powder is doped in the transparent packaging glue 7 . In addition, the upper surface of each LED 8 is formed into an arc surface by the transparent packaging glue 7 . Likewise, because the transparent encapsulant 7 has certain viscosity and surface tension, it will not flow out along the first half etching groove 2 .

In step S405 , a second half-etched groove communicating with the first half-etched groove is etched on the bottom of the etched metal sheet.

In order to completely separate the positive and negative poles, and ensure that the distance between the positive and negative poles at the bottom of the LED product is suitable for patch welding. Here, the second half-etched groove 9 communicating with the first half-etched groove 2 is etched at the bottom of the metal etching sheet 1 , as shown in FIG. 13 . Wherein, the width (0.2-0.5 mm) of the second half-etched groove 9 is larger than that of the first half-etched groove 2 , and the metal etching sheets on both sides of the second half-etched groove 2 are respectively used as positive and negative poles of the LED 8 . It should be noted that the first half-etched groove 2 and the second half-etched groove 9 constitute the aforementioned "convex" shaped through groove.

In step S406, each LED is cut out.

In the embodiment of the present invention, before cutting out each LED 8 , a solder resist material 10 (such as solder resist silica gel) is filled in the second half-etched groove 9 , as shown in FIGS. 14-16 . Firstly, it helps the bonding of the positive and negative metal sheets of the LED 8 and improves the reliability of the entire LED 8; secondly, it ensures that the solder paste at the application end will not be short-circuited.

Fig. 17 shows the implementation flow of the LED packaging method provided by the second embodiment of the present invention, which is described in detail as follows.

In step S1701, a plurality of parallel etching grooves are etched on the etched metal sheet, the etching grooves run through the etched metal sheet, the width of the lower part is greater than the width of the upper part, and the edges of the etched metal sheet are intact.

In the embodiment of the present invention, a plurality of parallel etching grooves are etched on the metal etching sheet 1, the etching grooves run through the metal etching sheet 1, the width of the lower part 9 is greater than that of the upper part 2, and the edge 10 of the metal etching sheet is intact. Preferably, the width of the upper part 2 of the etching groove is equal to the shortest distance between the positive and negative electrodes of the LED flip-chip chip 3, which is convenient for welding the LED flip-chip chip 3 in the subsequent process, and the depth of the upper part 2 of the etching groove is slightly larger than that of the LED flip-chip chip. The shortest distance between the positive and negative poles of the wafer 3 is shown in Figures 18 and 19. Wherein, the thickness of the metal etching sheet 1 is preferably 0.05-0.5 mm. Because the size of the manufactured LED product is determined by the size of the positive and negative electrodes of the etched sheet, it is easy to make a packaged product of the etched sheet bracket with the same size as the conventional LED packaged product.

In step S1702, the positive and negative electrodes of the LED flip chip are soldered to both sides of the upper part of the etching groove respectively.

In the embodiment of the present invention, a plurality of LED flip-chip chips 3 are obtained first, and then the positive and negative electrodes of each LED flip-chip chip 3 are eutectically soldered to both sides of the upper part 2 of the etching groove, as shown in FIGS. 20 and 21 . It should be noted that the positive and negative electrodes of the LED flip chip 3 are located at the bottom thereof, one of which is a positive electrode and the other is a negative electrode.

In step S1703 , coating the fluorescent glue covering the LED chip on chip on the metal etching sheet and curing it.

In the embodiment of the present invention, the fluorescent glue 4 covering the LED chip-on-chip 3 is coated on the metal etching sheet 1 and cured, as shown in FIGS. 22-25 . Specifically, the applicant can adopt the method of coating fluorescent glue on the surface of the LED flip chip disclosed in the patent application document with the document number CN102544260A. If grooves are used to standardize the fluorescent glue 4 , when etching the etching groove 2 , grooves 6 are etched around the area where the LED flip chip 3 is fixed, as shown in FIGS. 24 and 25 . Wherein, the thickness of the fluorescent glue 4 is preferably 0.03-0.5 mm. Because the fluorescent glue 4 has a certain viscosity and surface tension, it will not flow down or out along the etching groove 2 .

In step S1704, an adhesive tape is pasted on the lower surface of the etched metal sheet.

The embodiment of the present invention is to protect the metal layer at the bottom of the etched metal sheet 1 and prevent it from adhering to the transparent silica gel in the subsequent process. On the lower surface of the etched metal sheet 1, stick an adhesive tape 5 that can withstand high temperature (150°C, the baking temperature of silica gel), As shown in Figure 26.

In step S1705 , forming a transparent encapsulation glue covering the fluorescent glue on the etched metal sheet, the transparent encapsulation glue is blocked by an adhesive tape to fill the etching groove, and then the transparent encapsulation glue is cured.

In the embodiment of the present invention, a transparent packaging glue (such as transparent silica gel) 7 covering the fluorescent glue 4 is molded on the metal etching sheet 1 and cured, as shown in FIGS. 27 and 28 . Wherein, the transparent encapsulant 7 is also filled in the etching groove and blocked by the adhesive tape 5 . In order to enhance the light spot uniformity of LED products, a certain proportion of silicon dioxide powder is doped in the transparent packaging glue 7 . In addition, the upper surface of each LED 8 is formed into an arc surface by the transparent packaging glue 7 . Likewise, because the transparent encapsulant 7 has a certain viscosity and surface tension, it will not flow out along the upper part 2 of the etching groove.

In step S1706, the edge of the metal etching sheet and the adhesive tape are removed, and each LED is cut out, and the metal etching sheets on both sides of the etching groove are respectively used as positive and negative electrodes of the LED.

As shown in Figures 29 and 30, in the embodiment of the present invention, the adhesive tape 5 is torn off first, and then the edge 10 of the metal etching sheet is cut off to completely separate the positive and negative poles of each LED 8, and finally cut according to the cutting line 11 shown in Figure 30 8 out of each LED. After cutting, the metal etching sheets on both sides of the etching groove are used as the positive and negative poles of the LED 8 respectively. It should be noted that the etching groove is the aforementioned "convex" shaped through groove.

To sum up, the LED packaging method provided by the embodiment of the present invention has the following advantages:

1. The bottom electrode of the LED flip-chip chip is eutectic on the metal etching chip, and the packaging process is stable and convenient;

2. Coating and molding fluorescent glue and transparent packaging glue are carried out on the metal etching sheet, which has high material utilization rate and reduces packaging cost;

3. The LED packaged in this way only consists of silica gel, metal electrode sheets, flip chip and fluorescent glue coated on the surface of the chip. The materials are simple and stable, and the reliability of LED products is correspondingly good.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. within range.

Claims (6)

1. a LED, it is characterised in that include as LED positive and negative electrode the first metal etch sheet and Second metal etch sheet and positive and negative electrode are respectively welded in described first metal etch sheet and the second metal etch The LED overlay crystal chip of sheet, described LED overlay crystal chip is covered by fluorescent glue, and described fluorescent glue is by transparent envelope Two sides formation that dress glue covering, described first metal etch sheet and the second metal etch sheet are close to each other " convex " shape runs through groove, and described transparent enclosure glue is filled in described " convex " shape simultaneously and runs through the top of groove, institute Stating " convex " shape to run through the under-filled of groove and have anti-welding material, described " convex " shape runs through the top of groove prior to institute " convex " shape described in stating runs through the lower etch of groove and forms.

2. LED as claimed in claim 1, it is characterised in that the region week of fixed described overlay crystal chip Enclose the groove being etched with in order to specification fluorescent glue.

3. LED as claimed in claim 2, it is characterised in that described " convex " shape runs through groove top Width is equal to the minimum range between LED overlay crystal chip positive and negative electrode.

4. LED as claimed in claim 1, it is characterised in that the thickness of described metal etch sheet is 50～500 μm。

5. LED as claimed in claim 4, it is characterised in that the thickness of described fluorescent glue is 30～500 μm。

6. LED as claimed in claim 5, it is characterised in that each LED upper surface is by described transparent envelope Dress gum forming is cambered surface.