Photocrosslinking of ferroelectric polymers and its application in three-dimensional memory arrays

An I-line photolithography process for ferroelectric polymers is developed. It is based on photocrosslinking using a bisazide photoinitiator. Patterned layers were realized down to 1–2 μm resolution. Crosslinking yields a close-to-insoluble ferroelectric polymer network that counter intuitively has similar ferroelectric properties as a noncrosslinked film. The negative process is used to stack ferroelectric films on top of each other to make three-dimensional cross-bar arrays of nonvolatile ferroelectric capacitor memories.