High-Reliability Fine-Pitch RDL on Glass with Superior Electrical Performance for Heterogeneous Integration

As AI cloud infrastructures and ultra-high-speed data transfer technologies continue to evolve and scale toward mass production, advanced chiplet-compatible interposers are emerging as a key enabler for next-generation semiconductor packaging in AI data center servers. In particular, high-density interposer technologies utilizing silicon or glass are essential to achieve high-bandwidth, low-latency interconnections among heterogeneous chiplets.

In this paper, we report on the development of RDL(Redistribution Layer) interposer suitable for high density, fine wiring, and high-speed transmission, as well as on the formation technology of fine wiring at 2-µm pitch, protective film formation technology to ensure reliability, and demonstration results in a 300 x 400 mm size to accommodate the increase in chip size. Furthermore, we conducted electromigration tests on our proposed inorganic dielectric-coated wiring with wiring widths of 1 µm and 2 µm, and carried out electrical evaluations and discussions. These results indicated that, compared to conventional wiring, our proposed structure enables finer dimensions while maintaining higher reliability.