Bond aligner

06/01/1997

Bond aligner

This new tool aligns a stack of up to three transparent or nontransparent wafers (up to 6 ? 6 in.) for a subsequent bonding step and is equipped with the Inter-Substrate-Alignment System (ISA-System), which requires alignment targets only on the bond sides. The ISA principle aligns wafers by placing two pairs of video image microscopes between two substrates. Each pair consists of two accurately adjusted microscopes for simultaneous viewing of the two surfaces to be bonded. The alignment of the wafers is performed manually; then the ISA microscopes are retracted and the aligned wafers are brought together within a close gap, sufficiently separated to prevent premature wafer bond contact. High-precision guide rails ensure an accurate vertical substrate movement and guarantee an overall alignment accuracy of 3 ?m. Karl Suss, Garching, Germany; ph 49/89-3200-7150, fax 49/89-3200-7129.