| Title |
Reflectivity and Thermal Shock Properties of Sn-3.5Ag Electroless-plated Deposit for LED Lead Frames |
| Authors |
기세호(Se Ho Kee); 김원중(Won Joong Kim); 정재필(Jae Pil Jung) |
| DOI |
https://doi.org/10.3365/KJMM.2013.51.2.089 |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
alloys; plating; surface; thermal analysis; reflectivity |
| Abstract |
The surface roughness and reflection characteristics of electroless-plated Sn-3.5 wt%Ag on a LED (light emitting diode) lead frame were investigated. Cu electroplating was carried out prior to electroless plating of Sn-3.5Ag to improve the reflectivity of the Sn-3.5Ag deposit. A thermal shock test was performed to evaluate the stability of the deposits, namely the surface roughness and the reflectivity of the Sn-3.5Ag layer. The experimental results revealed that the surface roughness of the Sn-3.5Ag deposit was 0.135μm (arithmetical average roughness, Ra), 1.77 μm (maximum height roughness, Rmax) and the reflectivity was 1.86 GAM. After 500 thermal shock cycles of the Sn-3.5Ag deposit between 85℃ and -55℃, the surface roughness became 0.145 μm (Ra) and 1.93 μm (Rmax), and the reflectivity was 1.76 GAM, which indicates that the Sn-3.5Ag deposit was stabilized by 500 thermal cycles. |