An IC structure comprises a substrate, a first dielectric structure, a second dielectric structure, a first via structure, and a memory cell structure. The substrate comprises a memory region and a logic region. The first dielectric structure is over the memory region. The second dielectric structure laterally extends from the first dielectric structure to over the logic region. The second dielectric structure has a thickness less than a thickness of the first dielectric structure. The first via structure extends through the first dielectric structure. A top segment of the first via structure is higher than a top surface of the first dielectric structure. The first memory cell structure is over the first via structure.