Session: 13-02-01: Design and Fabrication, Analysis, Processes, and Technology for Micro and Nano Devices and Systems

Paper Number: 144986

144986 - Photopatternable Flexible Piezoelectric Polyimide/cobalt Iron Oxide Composite for Mems Applications 

Piezoelectric composite films for Microelectromechanical systems (MEMS) applications is growing in demand due to their unique ability to have their properties be tailored for their precise application. Typically, polymeric thin films are used as the matrix material for the composite to offer flexible mechanical properties. However, most of the composite films investigated to date are difficult to integrate into a MEMS fabrication process due to patterning issues. Etching composite films can be difficult using wet or drying etching as the user needs to develop a new etching process for each material that can etch the polymer and nanoparticles. This paper will investigate using HD-4100 polyimide, which is a photodefinable polymer that is patterned using standard photolithography methods. The HD-4100 is renowned for its exceptional thermal stability, mechanical strength, and dielectric performance, making it invaluable in a wide array of applications. Polyimides are widely used in MEMS as they can provide insulation, protection, and structural support to delicate electronic and mechanical components. Their versatility across industries, including microelectronics, aerospace, medical devices, and optoelectronics, emphasizes their important role in advancing technological innovation and driving progress in various fields. Recent advances have demonstrated that PI can be used as a matrix to create multifunctional materials including piezoelectric lead zirconate titanate. Additionally, the incorporation of CoFe₂O₄ (CFO) nanoparticles into piezoelectric polymer matrix polyvinylidene fluoride (pvdf) matrices has garnered significant attention, as it can enhance the materials magnetic properties. However, as stated previously these required complex patterning which limits its ability to be integrated into a MEMS device.  This study investigates the development of PI/CFO composite using PI-4100 as the matrix.  The study investigates optimization of the photolithography process used to pattern the material and characterization of the materials properties. Understanding the optimization of PI-CFO composite thin films, particularly in relation to developer (PA-401D) dwell time, holds paramount importance in advancing MEMS technology.

This research examines refining the resolution of PI composite thin films infused with 5 wt.% CFO nanoparticles. The investigation focuses on optimizing development time (60 sec, 90 sec, and 120 sec) and i-line (365nm) UV exposure intensity. The analysis emphasizes that the pinnacle conditions for achieving improved resolution entail a developer time of 60 sec combined with a transmission power of 50%. This optimal resolution was achieved with a 60 sec developer time and 50% of transmission power proceeds from a delicate interplay of chemical and optical processes. An ideal developer time of 60 sec ensures the comprehensive removal of uncured material, while the 50% transmission power strikes a balance between effective curing and minimizing overexposure. Collectively, these factors lead to sharper pattern edges and enhanced resolution in the PI composite thin films where we were able to achieve resolution down to 10μm. This study provides valuable information for enhancing the performance of PI composite thin films in various technological applications.

Presenting Author: Fazli Akram University of New Mexico

Presenting Author Biography: NA

Authors:

Fazli Akram University of New Mexico
Zeynel Guler University of New Mexico
Akanksha Adaval University of New Mexico
Ranjith Janardhana University of New Mexico
Nathan Jackson University of New Mexico