Drop Test for Electroless Nickel Electroless Palladium Immersion Gold (ENEPIG) Surface Treatment Application That is Suitable to a Low-Cost, Fine Pitch and Easy Fabrication

Abstract

For an application of fine pitch Ball Grid Array (BGA) or Land Grid Array (LGA) packages, ENEPIG is a promising surface finish technology of low cost, fine pitch and easy fabrication. In this paper, we study the drop test, one of the most important items of hand held device reliability test, of ENEPIG surface finished packages. This paper focuses on the drop test performance of a bond between the main board and three kinds of packages. Those packages are designed with a daisy chain for a detection of open/short during the drop test. The main board has a bar type outline and is suitable for an In-Situ data acquisition. Drop tester is composed of a drop test unit, a high speed resistance meter and a data acquisition system (PC). JEDEC Condition B (1,500G and 0.5milliseconds duration time and half-sine pulse) in JESD22-B111 Table 1 or in JESD22-B104-C Table 1 is applied as a test condition. After the drop test, the joint geometry and the intermetallic compound (IMC) of failure samples are analyzed through the cross section method. The result shows no breaks at the solder joint of package side. All breaks, however, are originated from the solder joints of main board side. It is a significant outcome of this work to show no performance difference between ENEPIG and Electrolytic Ni/Au.