Topology optimization for optical microlithography with partially coherent illumination

Abstract

SUMMARYThis article revisits a topology optimization design approach for micro-manufacturing and extends it to optical microlithography with partially coherent illumination. The solution is based on a combination of two technologies, the topology optimization and the proximity error correction in micro-/nano-lithography. The key steps include (i) modeling the physical inputs of the fabrication process, including the UV-light illumination source and the mask, as the design variables in optimization and (ii) applying physical filtering and heaviside projection for topology optimization, which correspond to the aerial image formulation and the pattern development processes, respectively. The proposed approach results in an effective source and a binary design mask, which can be sent directly to fabrication without additional post-processing steps for proximity error correction. Meanwhile, the performance of the device is optimized and robust w.r.t. process variations, such as dose / photo-resist variations and lens defocus. A compliant micro-gripper design example is considered to demonstrate the applicability of this approach. CCC Received . . .

Topology optimization of compliant mechanisms with stress constraints and manufacturing error robustness

“…Over-or under-exposure and over-or under-etching are common sources of uncertainty in this field and motivated the robust formulation by [7]. Deeper investigations of these effects together with actual physical modeling of micro-and nano-lithography processes as a part of the topology optimization process have been discussed in [18][19][20][21]. Non-uniform manufacturing uncertainties have also been investigated for compliant mechanism design by [11], but the conclusion of that paper was that this did not result in significantly different designs compared to the uniform variations approach.…”

Improving the efficiency of solar cells by upconverting sunlight using field enhancement from optimized nano structures

“…A combined topology-optimization and PEC approach, which integrates manufacturing constraints and thus ensures realizability, is described in Refs. [42,43].…”

Designing meta material slabs exhibiting negative refraction using topology optimization

“…It is therefore valuable to know how production errors affect the designs performance. Common manufacturing errors in micro-nano-processing are over-and under-etching or over-and under exposure which can be observed as near uniform erosion or dilation of manufactured devices (Zhou et al, 2016;Jansen et al, 2013). Hence, this section presents an investigation of how uniform dilation/erosion of the optimized design considered in section 7.2, optimized for multiple incoming angles, affects its transmittance and index of refraction.…”