| 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. |
|
|
| Key Words |
| alloys, plating, surface, thermal analysis, reflectivity |
|
|
 |
|
