Performance of SR Lithography in Giga-bit DRAM Fabrication.

Abstract

We have studied the characteristics of replicated resist pattern by synchrotron radiation (SR) lithography on the real topographic substrates such as a dynamic random access memory (DRAM) structure. Two type topographic structures; the step height between memory cell area and peripheral circuit area, which is regarded as the deviation of the mask/wafer gap and causes the difference of the optical image at each area, and small topographic structure in the memory cell area where the resist thickness changes continuously. It was found that the critical dimension (CD) was controlled within ±10% CD at the range of the proximity gap 14µm and a high contrast resist is effective to control the CD deviation in the memory 0 cell area. On the real DRAM topographic structure at the height of 500A, we obtained the CD deviation of 0.014µm(36) for 0.14µm transfer gate pattern. These results show SR lithography is the promising technique for giga bit scale device fabrication.

Proposal of Lithography using LB Film Resist and EBEP Etching.

“…Several approaches are being worked out to obtain fine pattern lithography below 100 nm. The major competitors for this work are X-ray lithography and electron beam (Ebeam)lithography [1,2]. For the high resolution E-beam lithography, one of the major limitation is the thickness of the resist film.…”

Quantification of the extent of reaction in a negative, novolac-based, chemically amplified resist

“…[2][3][4][5][6] The sensitivity of this resist formulation, however, is not sufficient for use as a production-compatible x-ray resist. [2][3][4][5][6] The sensitivity of this resist formulation, however, is not sufficient for use as a production-compatible x-ray resist.…”