Die-to-Wafer (D2W)

Die-to-Wafer (D2W) is an advanced semiconductor packaging and 3D integration technique in which individual semiconductor dies are bonded onto a target wafer. Unlike traditional wafer-to-wafer (W2W) bonding, where two complete wafers are joined together, D2W allows only selected dies—typically known-good dies (KGD)—to be integrated onto a wafer. This significantly improves manufacturing yield and enables heterogeneous integration.

D2W vs W2W

Characteristic Die-to-Wafer (D2W) Wafer-to-Wafer (W2W)
Bonding unit Individual dies Entire wafers
Yield Higher (KGD selection) Lower when one wafer contains defects
Throughput Lower Higher
Heterogeneous integration Excellent Limited
Chiplet support Ideal Less flexible
Manufacturing complexity Higher Lower

W2W offers superior throughput because complete wafers are bonded in a single operation. However, if either wafer contains defective dies, yield losses can be significant. D2W addresses this issue by allowing only tested, functional dies to be assembled.

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