Wafer-level underfill is a technique for IC packaing with use of pre-applied underfill (or non-flow underfill or non-conductive film (NCF) underfill) at wafer-level, instead of chip-level by using the conventional capillary underfill (CUF).
Types of Underfill
- Capillary Underfill (CUF) (into gap between chip and substrate)
- Standard CUF are typically designed to cure at about 150 °C.
- Pre-Applied Underfill
- Non-Conductive Paste (NCP) (pre-applied on substrate)
- Anisotropic Conductive Paste
- Wafer-Level Underfill (WLUF) (pre-applied on wafer or chip)
- Non-Conductive Film (NCF) (pre-applied on wafer or chip)
- Non-Flow Underfill (pre-applied on wafer or chip)