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LED heating heat sink rear using laser and heat sink bonding method

A LED chip and heat sink technology, which is applied in the field of LED chip and heat sink bonding, can solve problems such as gasification, failure to ensure reliable bonding of LED chip and heat sink, and solder oxidation, so as to avoid oxidation and gasification, and facilitate The effect of automation and high production efficiency

Inactive Publication Date: 2008-11-12
HARBIN INST OF TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In order to solve the problem that the laser is directly irradiated on the solder layer, the solder will be oxidized or even gasified due to the rapid temperature rise in a short period of time, and the reliable bonding between the LED chip and the heat sink cannot be guaranteed, and a laser is proposed. The method for bonding the LED chip heated by sinking the back and the heat sink, the specific steps of the present invention are:

Method used

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  • LED heating heat sink rear using laser and heat sink bonding method
  • LED heating heat sink rear using laser and heat sink bonding method
  • LED heating heat sink rear using laser and heat sink bonding method

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Experimental program
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specific Embodiment approach 1

[0012] Specific implementation mode one: combine image 3 , to illustrate the LED chip and heat sink bonding method described in this embodiment using laser heating on the back of the heat sink. Its specific steps are:

[0013] Step 1. Plating Au on the back of the LED chip 3-1 and the pads of the heat sink 3-2 respectively;

[0014] Step 2, plating or printing a solder layer 3-3 on the gold-plated Au pad;

[0015] Step 3, paste the LED chip 3-1 on the solder layer 3-3 of the gold-plated Au pad;

[0016] Step 4: Use the laser beam 3-4 to align the backside of the gold-plated Au pad on the heat sink 3-2 and heat until the solder layer 3-3 melts.

[0017] The shape of the heat sink 3-2 in this embodiment is flat, U-shaped or fin-shaped.

[0018] The material of the heat sink 3-2 in this embodiment is copper Cu or aluminum Al.

[0019] The solder layer 3-3 in this embodiment mode is SnAg, SnAgCu, or PbSn.

[0020] In this embodiment, the laser beam 3-4 is used to locally hea...

specific Embodiment approach 2

[0021] Embodiment 2: In this embodiment, the bonding method described in Embodiment 1 is used to realize the bonding of multiple LED chips 3-1 and the heat sink 3-2. The specific process is as follows:

[0022] Repeat step 1 to achieve gold-plated Au on multiple pads on the back of multiple LED chips 3-1 and on the heat sink 3-2;

[0023] Repeat step 2 to plate or print solder layers 3-3 on multiple gold-plated Au pads;

[0024] Repeating step 3, attaching multiple LED chips 3-1 to the solder layers 3-3 of multiple gold-plated Au pads;

[0025] The heat sink 3-2 or the laser beam 3-4 is moved manually or automatically, and step 4 is repeated to realize the bonding of the LED chips 3-1 and the heat sink 3-2 one by one.

[0026] In this embodiment, the bonding of multiple LED chips 3 - 1 and the heat sink 3 - 2 is realized by repeating the steps described in the first embodiment.

[0027] The mounting of the brazing laser output lens 3-5 and the LED chip 3-1 in this embodiment...

specific Embodiment approach 3

[0028] Specific implementation mode three: combination Figure 5 , to describe this embodiment. The difference between the present embodiment and the specific embodiment 1 or 2 is that in the step 4, the laser spot pointer 3-7 is used to realize the alignment of the gold-plated Au pad with the laser beam 3-4.

[0029] The alignment method described in this embodiment is as follows: place the laser spot indicator 3-7 above the heat sink, fix the brazing laser output lens 3-5, and move the laser spot indicator 3-7 so that The laser indicating light 3-6 output by it coincides with the brazing laser beam 3-4 output by the brazing laser output lens 3-5, and the LED chip 3-1 to be bonded is positioned at the position by moving the heat sink 3-2. 3-6 times of the above-mentioned laser pointing light.

[0030] In this embodiment, a laser spot indicator 3-7 is added, which simplifies the alignment method between the laser beam 3-4 and the gold-plated Au pad, and facilitates automatic...

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Abstract

The invention relates to a method for bonding an LED chip and heat sink by adopting laser to heat the back of the heat sink, in particular to a method for bonding an LED chip and heat sink; the method solves the problems that when the laser beams directly radiate on a brazing filler metal layer, the brazing filler metal is to undergo oxidization and even vaporization due to rapid temperature raising in a short time, and the reliable bonding of the LED chip and heat sink cannot be ensured. The specific steps of the method are as follows: first, the metal Au is plated on the back of the LED chip and the bonding pad of the heat sink; then, the brazing filler metal layer is plated or printed on the Au-plated bonding pad; the LED chip is attached on the brazing filler metal layer of the Au-plated bonding pad; laser beams are pointed to the position on the back of the heat sink where the LED chip is positioned until the brazing filler metal is melted. The method has the advantages that: the laser beams heat the position on the back of the heat sink where the chip is positioned to avoid oxidation and vaporization of the brazing filler metal; a plurality of chips can be attached on the position waiting for bonding in advance and then bonding can be conducted. The method can be applied to the field of LED chip packaging.

Description

technical field [0001] The invention relates to a bonding method of an LED chip and a heat sink, which belongs to a method of LED chip packaging. Background technique [0002] With the development of LED chips in the direction of high power, the problem of heat dissipation becomes more and more prominent. Improving the packaging structure, adopting a new design concept and low thermal resistance packaging structure and technology is becoming the direction of efforts in the LED industry. [0003] In traditional packaging methods, there are usually a variety of high thermal resistance materials sandwiched between the chip and the heat sink, such as ceramic substrates, adhesive layers or gaskets, etc., which form the heat dissipation bottleneck in the chip package. Therefore, simplifying the packaging level and process between the chip and the heat sink is bound to and is becoming a development trend of power LED packaging. [0004] In the invention patent application with pu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01L33/00H01L21/50B23K1/005B23K1/20
Inventor 王春青田艳红孔令超杨罡
Owner HARBIN INST OF TECH
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