Precise downsizing of a <100-um thin die out of a package prior to delayering

Figure 1. LatticeAx indent and cleaving system.

Figure 2. Diamond wedge indenter close to the sample surface.

Figure 3. Left. Sketch of wedge indenter separating the sample Right. Sample downsized using the LatticeAx.

Delayering is used to prepare thin die removed from their packages for fault isolation and failure analysis. To precisely delayer a sample its size must be reduced.  Downsizing the sample size prior to polishing minimizes edge rounding and improves control of the planar polishing. Centering the area of interest (AOI) prior to polishing also improves success rate compared to samples with targets on the edge of the sample. Handling small (typically <10mm square) and thin <100 micron thick samples is difficult. The samples are prone to chipping and loss of the AOI. A fabless semiconductor company was looking for a fast, clean more successful method to replace their current sawing or hand cleaving process. They used the LatticeAx indent and cleaving system (Figure 1), and it is now their process of record.

A diamond wedge indenter is precisely positioned on the sample to control the location of the cleave. As the indenter is lowered it creates a defect on the sample surface that eventually causes a cleave to propagate (Figures 2 and 3). This simple process results in a clean sample without damage to the sample edges (Figure 4).

Figure 4. Left. Thin sample after downsizing using sawing. Right. Thin sample after cleaving with the LatticeAx


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