4. Integrated process flow. Design a process flow to fabricate the microstructure shown below. Try to use as few masks and lithography steps as possible. Please indicate details of each step, including UV exposure method (type of photoresist used, contact, proximity, or projection exposure), thin film deposition (PECVD, LPCVD, or others.) and etching method (chemical used in wet etching, RIE etching or others), and explain why this method was chosen. Integrated process flow. Design a process flow to fabricate the microstructure shown below. Try to use as few masks and lithography steps as possible. Please indicate details of each step, including UV exposure method (type of photoresist used, contact, proximity, or projection exposure), thin film deposition (PECVD, LPCVD, or others.) and etching method (chemical used in wet etching, RIE etching or others), and explain why this method was chosen