Aluminum Sputtering Target

A new high-strength aluminum sputtering target, made using a patented breakthrough aluminum-processing technique that yields the finest-grain aluminum microstructure in the semiconductor industry, is available from AlliedSignal Electronic Materials (ASEM), Wafer Fabrication Materials (WFM). WFM is a strategic business enterprise of ASEM providing materials used in the production of advanced integrated circuits. The sputtering target is produced by ASEM's Wafer Fabrication Materials (WFM), formerly Johnson Matthey Electronics, a supplier of components and thin-film deposition materials to the semiconductor and microelectronics industries. The new APX UF (ultra fine) is a precipitate-free sputtering target whose superior material strength makes it ideally suited for high-power, sub-0.25-micron physical vapor deposition (PVD) processing of semiconductor wafers up to 300 mm in diameter.

ASEM's Wafer Fabrication Materials' (WFM) new target has a typical grain size of 0.5 micron, whereas the traditional process of forging and rolling aluminum yields grain sizes ranging from 50 to 200 microns. A feature of this new target is extremely fine precipitate distribution with a reduction of over 1000 times in average size as compared to traditional targets. Finer grains improve the microstructure of the target by dramatically reducing the size distribution. This translates directly to a smoother, more consistent sputtering surface which provides customers with fewer defects caused by arcing. In fact, field tests have showed an over 60% reduction in cumulative arcing levels compared with conventional processed material. Aluminum sputtering targets are used during the PVD process for depositing thin films of high-purity material onto a wafer. PVD continues to grow in importance as the number of circuit layers on chips continue to increase.

With the global semiconductor industry considering a transition to larger 300mm diameter wafers, sputtering targets must be made bigger, but they also must be stronger to resist warping during high temperature processing. The transition to 300mm PVD processing increases the tendency for target warping due to the large target diameters (over 20" in size). Conventionally processed high purity Al-0.5%Cu (the leading interconnect alloy) has low mechanical strength. Testing has shown that APX UF grade materials show over a 5 times increase in material strength compared to conventionally processed high purity Al.

AlliedSignals, Electronic Materials Headquarters, 101 Albright Way, Suite D, Los Gatos, CA 95030. Tel: 408-341-3000. Fax: 408-341-3001.