Advanced wafer thinning technologies to enable multichip packages

Wafer thinning for advanced packaging methods has gained importance as demand has increased for memory cards, portable computing systems, multiple chip packages (MCPs), and other applications that require thin integrated circuits (ICs). This paper gives an overview of the different industrial wafer thinning techniques - backgrind, poligrind, dry mechanical polishing, chemical mechanical polishing (CMP), wet etch, dry etch, and dice before grind (DBG) - and the challenges encountered during thinning of wafers to less than 100mum. Some reliability issues have also been investigated, including die strength and subsurface damage associated with these processes and mechanical properties, such as surface roughness and wafer warp