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Solder for flip chip LED and application thereof

A solder and flip-chip technology, applied in the direction of welding/cutting media/materials, welding media, welding equipment, etc., can solve the problems of poor heat dissipation and reliability, reduce soldering void rate, and low production efficiency, so as to improve stability and Reliability, improved heat dissipation performance, and improved productivity

Inactive Publication Date: 2019-01-11
YUNNAN KEWEI LIQUID METAL VALLEY R & D CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The solder has good thermal conductivity and can transfer heat to the substrate for heat dissipation; at the same time, the solder has low hardness, which can effectively absorb the thermal stress generated by material expansion in the chip and improve the stability and reliability of the chip; and the solder Separated from the flux, it can greatly reduce the void rate of soldering, thus solving the shortcomings of traditional flip-chip LED such as complex process, high production cost, low production efficiency, high post-solder void rate, poor heat dissipation performance and reliability, etc.

Method used

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  • Solder for flip chip LED and application thereof
  • Solder for flip chip LED and application thereof
  • Solder for flip chip LED and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] Embodiment 1 A kind of solder for flip-chip LED

[0047] A kind of solder used for flip-chip LED chips is a Sn-Zn-Cu alloy material, wherein, in terms of mass percentage, the content of Sn is 80%, the content of Zn is 18.5%, and the content of Cu is 1.5%.

[0048] The melting point of the solder ranges from 220°C to 300°C, the thermal conductivity is greater than 70W / (m·K), and the hardness is 16HV, which can effectively absorb the thermal stress generated by the heating of the substrate and chip.

Embodiment 2

[0049] Embodiment 2 Preparation of a kind of solder for flip-chip LED

[0050]The preparation of the solder uses a vacuum high-frequency induction melting furnace for secondary melting, and argon is filled as a protective gas during the melting process to prevent metal oxidation. The metal is melted at high temperature for the first time, and mechanically stirred at medium temperature for the second time to homogenize the components of the alloy.

[0051] After the preparation is completed, the alloy solder is cast into blocks, and pressed into tablets by a tablet press.

[0052] For different pad 300 shapes, utilize laser or mold to cut out required thin solder sheet 200, thick solder sheet 201, complete the preparation of solder sheet 2.

Embodiment 3

[0053] Embodiment 3 A flip-chip LED (single chip)

[0054] A flip-chip LED chip, such as image 3 , Figure 4 , consisting of a substrate, pad, solder layer, and chip from bottom to top; and fill the gap between the substrate and the chip, and around the solder layer with insulating heat-conducting glue.

[0055] Wherein, the pads can be copper pads, aluminum pads, etc.; there is no solder bump or electroplated solder layer on the pads.

[0056] Wherein, the chip adopts GaAs, sapphire or silicon substrate material.

[0057] Wherein, the main component of the insulating and thermally conductive adhesive is selected from one or more of epoxy resin, acrylic resin, and silicone resin.

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Abstract

The invention relates to solder for a flip chip LED and application thereof. The solder is an Sn-Zn-X multi-component alloy, wherein X is selected from one or more of Al, Ag, Cu and Bi. The solder isprepared from in percentage by mass: 40-95% (preferably 50-85%) of Sn, 5-60% (preferably 7-50%) of Zn, and 0.5-15% (preferably 0.5-10%) of X. The solder has the beneficial effects that a packaging technology is simplified, and the production efficiency of a flip chip is improved; the working junction temperature of the chip is lowered, the welding voidage of the chip is decreased, the heat-dissipating property of the chip can be improved, luminous decay is lowered, the luminous efficiency of the chip is improved greatly, and the service life of the chip is prolonged greatly; and meanwhile, thesolder can absorb heat stress generated during working of the chip, and thus stability and reliability of the chip are improved.

Description

technical field [0001] The invention relates to a solder for flip-chip LEDs and its application, and belongs to the field of LED lighting flip-chip technology. Background technique [0002] The packaging process of LED mainly includes three packaging methods: front-mounted structure, vertical structure and flip-chip structure. Among them, flip-chip structure LEDs have gradually gained widespread attention in the lighting industry because they can be integrated and mass-produced, their preparation technology is mature, and their performance is excellent. [0003] The soldering process of traditional flip-chip LED chips mainly includes: (1) making of flip-chip solder bumps. The key to ball making is to ensure that the consistency of the ball is good, and the chip cannot be damaged when the ball is formed; (2) Print solder paste or dot conductive glue on the substrate pad. Solder paste mainly includes high-temperature solder paste and conductive silver glue, etc.; (3) The die...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B23K35/26B23K1/00H01L33/48H01L33/62H01L33/64
CPCB23K1/00B23K35/262H01L33/483H01L33/62H01L33/641H01L33/647H01L2933/0066
Inventor 田鹏蔡昌礼缪祥辉郭文波邓中山
Owner YUNNAN KEWEI LIQUID METAL VALLEY R & D CO LTD
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