Method for forming die bonding connection structure of reflective LED at low temperature

Abstract

The invention discloses a method for forming a die bonding connection structure of a reflective LED at low temperature, which comprises the following steps of: forming a first metal layer on a first surface of a base plate, and providing an LED epitaxial structure on a second surface of the base plate; forming a second metal layer on a base body, wherein the material of the second metal layer is different from that of the first metal layer; applying a force to the base plate and the base body so that the first metal layer and the second metal layer produce plastic deformation and are primarily bonded together; and heating the base plate and the base body in a high temperature furnace, wherein the first metal layer and the second metal layer are subjected to solid state diffusion in an interface to form a diffusion alloy layer.

Description

technical field [0001] The invention relates to a method for forming a reflective light-emitting diode crystal bonding structure at low temperature, in particular to a method for utilizing the physical characteristics of rapid diffusion of the gold / silver interface to achieve the goal of low temperature crystal bonding to avoid thermal expansion of different substrates A low-temperature method for forming a reflective light-emitting diode die-bonding structure due to thermal stress problems caused by different coefficients (CTE). Background technique [0002] Since light emitting diodes have the advantages of small size, high luminous efficiency, long life and rich color changes, it is expected that the applications of light emitting diodes will increase. Generally speaking, bare LED chips need to undergo packaging steps such as die bonding, wire bonding, glue sealing, and product classification before the chips can be commercialized to customers. The existing die-bonding m...

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Problems solved by technology

However, compared with silver colloidal die bonding, the die bonding equipment is more complicated and expensive (the die bonding machine needs to be equipped with a temperature control system and a pressure system), and the production capacity is also lower.

However, if high melting point metal soldering materials are used, such as gold tin (AuSn), gold silicon (AuSi), tin silver (SnAg), tin (Sn), etc., the light-emitting diode chip will be easily damaged due to high junction temperature ( Thermal stress due to difference in thermal expansion coefficient)

If you use low melting point metals, such as indium (In), indium silver (InAg), indium gold (InAu), bismuth tin (BiSn), etc. (about 70-80°C), due to the low melting point of the bonding layer, the material of the bonding layer will soften due to the rapid diffusion of atoms or the phenomenon of excessive growth of intermetallic compounds will occur, resulting in a significant decrease in the reliability of the joint decline

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