The effect of laser power pattern on the temperature and thermal stress distributions in LED die bonding process is investigated in this work. The wavelength of 940nm diode laser source is used in this study. The laser light is focus on the back of an AlN substrate. The eutectic Au80Sn20 solder metallized between die and substrate is soldered by the heat conducted from the controlled laser power. The finite element package software-MSC. Marc is employed to simulate the laser soldering process. The thermal-elastic-plastic models of the solid elements are used. The temperature dependent material properties are applied to characterize the temperature variation effect during the die bonding. The measured temperature data have also been used to derive the absorption coefficient, conductivity, specific heat of AlN substrate and the convection coefficient in free convection via the inverse engineering process. A difference between the simulated and measured temperature can be kept in 10%. The temperature and thermal stress distributions during the die bonding process have been simulated and studied. The distributions of residual stress induced in this die bonding process have also been studied. The effects of different laser soldering parameters, e.g. focus shift, defocus, inclined angle, on the die bonding are also studied.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0719112-123238 |
| Date | 19 July 2012 |
| Creators | Chan, Wei-yi |
| Contributors | none, none, Jao- hwa Kuang, none, none |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0719112-123238 |
| Rights | user_define, Copyright information available at source archive |
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