Material development for 3D wafer bond and de-bonding process

3D integration technology using through silicon via (TSV) is progressing for high volume manufacturing in various applications. Thin wafer handling using temporary bonding technology is an important process within 3D integration. There are several temporary de-bonding processes being developed and used in industry, such as thermal slide debonding, mechanical de-bonding and laser de-bonding. In general, thermal slide de-bonding materials, which consist of thermoplastic polymer, are considered to be the most suitable for high throughput and easy de-bonding. However, they also have the disadvantage of thermal resistance during 3D-IC processes such as PECVD process. In order to improve the thermal resistance, higher Tg materials should be considered but, high Tg materials often introduce additional wafer stress, and increase the difficulty of bonding and de-bonding. A new temporary bonding material has been developed for thermal slide de-bonding which provides high thermal resistance, low residual stress, easy bonding and de-bonding, good chemical resistance and easy cleaning after the de-bonding process. This paper will discuss a DOE conducted for adjusting rheological properties and the data showed that viscosity was drastically decreased and remain suitable for the bonding and de-bonding processes. The newly developed material is expected to contribute to future high performance in 3D-IC processes.