Advanced transfer system for spin coating film transfer and hot-pressing in planarization technology

A film transfer system suitable for the spin coating film transfer and hot-pressing (STP) method was developed. The STP method consists of three steps: spin coating a base film with a dielectric, transferring it from the base film to a wafer by hot pressing in a vacuum, and peeling off the base film from the dielectric. STP is simple and cost effective for film deposition and planarization, since both processes can be performed simultaneously. Among the above steps, the transfer step is the most crucial in achieving stable and reproducible transfer of a dielectric. To improve this step, we devised an arrangement of the base film and wafer, and introduced a tension ring for stretching the base film and a press force equalizer. Each technique was individually evaluated and proved to be effective. A low-k material (k = 2.9) was applied to the system and the overall effect of the three techniques working together was also investigated. The experimental results show that the system achieves better film transfer with the thickness variation of 1.8% on the wafer and that STP is a very promising key technology for planarization. (C) 2002 American Vacuum Society.