We evaluated laser ablation and sandblasting as preparation methods for package related failures and for backside analysis of ICs. With laser ablation we uncovered gold wedges on an internal board of a PLFBGA package without damage of the gold wires and the board metallization. This was possible by optimization of the laser pulse energy and the pulse repetition rate and by limitation of the ablation area. Sandblasting showed to be a gentle way for backside thinning down to 60 ìm silicon thickness. For a surface smoothness sufficient for IR imaging a subsequent planarization treatment is necessary.

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