Process Development for Novel Wafer Processing Using Laser-Induced High-Quality Cutting in Liquids

Heterogeneous 2.5D and 3D integration is key to continuously increasing computing and memory performance in the smallest possible space. Increasingly complex structures made up of ever-thinner chips, as well as so-called chiplets and interposers, are being developed to combine the advantages of different semiconductor materials within a single component or package.

The NewWAVE investment project, outlined in parallel, proposes a new liquid-assisted laser cutting process that offers significant advantages for processing at the 300 mm wafer level.

The aim of this R&D project, WAVE4Tech, is therefore to investigate the scientific principles and develop optimal processing parameters for the laser singulation of wafers made of various materials (e.g., Si, glass, compound semiconductors such as SiC or GaN) that are coated with various surface layers (e.g., superconducting TiN or low-k dielectrics). In comparison to conventional dicing methods such as sawing (blade) and standard laser dicing (stealth dicing), the influence of the set process parameters of the new laser dicing method on the width of the “dicing line,” chip stability, cracking at the chip edges, saw edge morphology, residual stresses caused by separation, and the formation of nano- and microparticles during processing. The goal is to increase the reliability of chips and chiplets for the optimal use of the liquid-assisted laser dicing process in the manufacture of heterogeneous 3D packages. This is the necessary foundation for providing optimal and novel high-density integration technologies of the next generations in advanced packaging for future fields such as high-performance computing, AI applications, or quantum computing.

For the characterization of the process results, IZM-ASSID is working closely together with Fraunhofer IKTS.