Recent experimental results of inverted pyramids passivated emitter and rear cells (IP-PERC) of varying thickness down to 63 ?m on FZ and Cz material are presented. The rear side contacts are made conventionally as well as by the laser-fired contacts (LFC) method . The Voc dependence on cell thickness of annealed and degraded Cz is measured. The investigated relationships can be modeled well by PC1D. Thus it is possible to predict the cell performance depending on thickness and bulk diffusion length. The wafers were thinned down from 250 ?m with new equipment (fully automatic infeed grinder) at Fraunhofer ISE labs.