The Problem With Copper Bond Wires…. For Designers

The Problem With Copper Bond Wires…. For Designers

In this short piece I’m linking Semi Design groups to an increasingly important discussion in the Semi Failure Analysis group. Here’s the link Why? Because materials decisions made about bonding and packaging are not just downstream from the design process, they have important effects on how a Design cycle can be shortened by facilitating – or inhibiting – verification, modification and test. As a Failure Analyst the reasons for getting into packages while leaving the devices functional is obvious (to understand problems) and is an important step as you can see from the active discussion linked here. But as a FIB-Chip Design-Nano Surgeon supporting design teams with circuit edit, I also need routine access to functional opened devices. Using FIB Nano-Surgery in the Design Verification process is quite commonplace, either to confirm metal fixes before implementing layout changes, or getting 1st Silicon through test and starting applications board testing. So the link between how you correct a design flaw and open a package, is increasingly important for shortening design times. The move from Gold to Copper bond wires shaves a finite fraction from the cost of bonding a device, but also presents an additional challenge for opening up these packages. The discussion here shows many different approaches being tried as people try to adapt the Gold or Aluminium compatible ‘opening’ processes and existing hardware, to handle Copper (instead of instantly dissolving it). Decap tool vendors provide valuable insight with information about their latest Copper specific solutions. The danger is that the unpredictable and sometimes involved process of Design Verification and specifically FIB nano-surgery, may not have been fully factored in to that cost/material decision along...