Negative-Tone Photosensitive Polymeric Bonding Material to Enable Room Temperature Prebond for Cu/Polymer Hybrid Bonding

This article presents an evaluation of a negative-tone i-line photosensitive polymeric bonding material for achieving prebonding in Cu/polymer hybrid bonding at low temperatures via the Cu damascene process. The polymeric material has a ${T}_{g}\le 100 ^{\circ }\text{C}$ ; Young's modulus of 99 MPa, the dielectric constant of 2.6, and dissipation factor of 0.0016 at 10 GHz. Shear tests revealed a bond shear strength of over 10 MPa when prebonded at 30 °C. Subsequent thermal compression bonding (TCB) at 300 °C for 1 h increased the bond shear strength to over 60 MPa. The material is compatible with the typical Cu damascene process involving lithography, Ti barrier layer deposition, Cu seed layer deposition, Cu electroplating, and Cu chemical mechanical polish (CMP). The photosensitive nature of the low- ${T}_{g}$ polymeric bonding material, along with its compatibility with the Cu damascene process, opens up possibilities for low-temperature Cu/polymer hybrid bonding.