Low-Dielectric-Constant Benzocyclobutene-Based Polysiloxane Resins with Excellent Photoimaging Properties

With the rapid rise of the Internet of things, high-frequency mobile communications, artificial intelligence, and other application scenarios, demand has been increasing for integrated circuits with a high performance, a low power, and a small size. However, in wafer-level packaging, the size reduction, wafer flatness, defect control, and controllable patterning requirements are already high. At the same time, the high degree of integration makes internal thermal management and signal transmission of the circuits more complex. Thus, the development of application-side photolithographically patternable low-dielectric (or ultralow-dielectric) materials has become a significant topic of interest in the chip industry. The main challenge involves the introduction of photoactive structures with beneficial dielectric properties. Herein, we propose a low-dielectric UV-curable resin with a large concentration of photoactive double-bonding groups in the structure. This low-dielectric resin is prepared by UV/thermal curing of a linear silicone-benzocyclobutene oligomer (BCB-LPS). Oligomeric BCB-LPS is prepared by a simple and efficient hydrolytic polycondensation reaction and then capped. In this manner, a large proportion of double bonds and BCB groups are introduced into the resin, allowing BCB-LPS to be both UV- and heat-cured. The cured BCB-LPS resin has high thermal stability, a high mechanical strength, a low dielectric constant, and a low dielectric loss as well as controllable lithographic patternability. Thus, this resin represents a generation of low-dielectric, lithographically patternable materials.