Pyrolyzed carbon as a true grayscale mask

Despite decades of promise, grayscale contact lithography remains a niche fabrication method. Part of this may be due to the inherent complexities of grayscale pattern transfer, but some of the slow progress may also be attributed to the lack of rapid affordable options for creating high fidelity grayscale masks. The recent emergence of direct write, multi-photon lithography makes grayscale lithography possible, however the serial nature of these direct write approaches do not scale well to high volume manufacturing. Here we demonstrate the conversion of 2.5D grayscale patterns written via multi-photon lithography into true grayscale masks for contact lithography via pyrolysis. We present a thorough analysis of the fabrication details and demonstrate micro-optical applications enabled with this new technology.