Abstract
On the implementation of LED flexible package model, the substrate was required to adopt the flexible material. This is to be applied to different styling of lamps or flexible 3C products. However, due to poor heat transfer of polymer substrate, LED operation power is limited. Also, high temperature and high thermal stress caused by die bonding process often damage the flexible substrate, making the bonding success rate being low. The production cost increase; therefore, LED flexible package model can’t be widely applied. The purpose of this study, that is to develop a set of low-temperature die attach material process applied to flexible polymer substrate. With the Parameter setting analysis, design of the overall structure will be completed. This research can be divided into two themes: Select the low melting temperature alloy as a die attach material, which can reduce operating temperature in die bonding, so as to make LED chip directly bonding on the polymer substrate. By the technology of laser drilling and copper electroless plating, flexible substrates with heat dissipation column are successfully fabricated. Furthermore, we conducted some experiments to show the characteristics of whole process, and also execute the LED lighting test to prove concrete feasibility. Through die shearing test of the die attach material and measurement of thermal resistance, reliability of this new flexible LED package process can be confirmed.