Effect of interface microstructure on the mechanical properties of Pb-free hybrid microcircuit solder joints
Although Sn-Pb eutectic alloy is widely used as a joining material in the electronics industry, it has well documented environmental and toxicity issues. Sandia National Laboratories is developing alternative solder materials to replace traditional Pb-containing alloys. The alloys are based on the Sn-Ag, Sn-Ag-Bi and Sn-Ag-Bi-Au systems. Prototype hybrid microcircuit (HMC) test vehicles have been developed to evaluate these Pb-free solders, using Au-Pt-Pd thick film metallization. Populated test vehicles with surface mount devices have been designed and fabricated to evaluate the reliability of surface mount solder joints. The test components consist of a variety of dummy chip capacitors and leadless ceramic chip carriers (LCCC`s). Intermetallic compound (IMC) layer reaction products that form at the solder/substrate interface have been characterized and their respective growth kinetics quantified. Thicker IMC layers pose a potential reliability problem with solder joint integrity. Since the IMC layer is brittle, the likelihood of mechanical failure of a joint in service is increased. The effect of microstructure and the response of these different materials to wetting, aging and mechanical testing was also investigated. Solid-state reaction data for intermetallic formation and mechanical properties of the solder joints are reported.
- Research Organization:
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 676869
- Report Number(s):
- SAND-98-1438C; CONF-981022-; ON: DE98006146; BR: DP0101031; TRN: AHC29821%%2
- Resource Relation:
- Conference: Institute for Interconnecting and Packaging Electronics Circuits/Surface Mount Technology Association electronics assembly expo, Providence, RI (United States), 27-29 Oct 1998; Other Information: PBD: [1998]
- Country of Publication:
- United States
- Language:
- English
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