S. Goh, J. Cho, Global Foundries, Singapore, Singapore

Summary: Resolution enhancement from diffractive solid immersion lens is well established. For backside laser based IC failure analysis (FA), although its performance has been demonstrated to be comparable to refractive solid immersion lens, it is less widely adopted. A conventional DSIL for backside laser based FA has three major drawbacks. First, it does not allow for multiple site analyzes. It is static The other drawback is the process dependent quality of lens such that performance may be affected significantly. This is especially so when the focused systems used to fabricate the lens is poorly maintained. The last factor is fabrication time. It is proportional to the size of lens. A larger lens gives higher resolving power but require longer time to fabricate which makes it unattractive for routine failure analysis. A mobile diffractive solid immersion lens (DSIL) design is proposed in this paper. It has the potential to overcome these limitations and will greatly enhance its industrial application for backside IC failure analysis.