Maskless lithography
The high and rising cost of photomasks (largely driven by writing times exceeding 24 h) is driving the exploration of maskless lithography for applications requiring throughput about 1cm2/s which is about one tenth that of an optical projection exposure system. Achieving this throughput with charged particle lithography requires currents 10,000 times larger than those presently used and hence sets up the need for charged particle optics radically different from those being used today. Achieving this throughput with optical maskless lithography at the required minimum features sizes of 65nm and below is a serious engineering challenge for the spatial light modulator. Meeting 10% or even 1% of the throughput requirement might still result in mask writing and inspection technologies that would lead to significantly less expensive masks. Furthermore, relaxing the requirements on control of individual edge positions (i.e., a fixed-shape projector) would significantly ease the above challenges.
maskless lithography electron beam optical lithography