Multilayer structure and its fabrication method

Abstract

Abstract A multilayer structure of the invention is fabricated by patterning a first electrically conductive layer on an insulative substrate; coating a polyamic acid resin layer all over the first electrically conductive layer; piercing a metal pin into the resin layer so that a first end of the pin contacts and is cold-welded to the first electrically conductive layer; hardening said polyamic acid resin to become polyimide resin; and patterning a second electrically conductive layer over the resin layer and the second end of the pin exposed from the surface of the resin layer. The cold-welding of the pin to the first conductive layer allows a reliable connection thereof. Moreover, this structure and method allow an improved flatness of each layer, resulting in an achievement of a larger number of the multilayers without the prior art problem of pattern breakage caused from less flat layers. The polyimide resin, which is not required to be photosensitive in the above fabrication method, can be employed so that its thermal expansion coefficient is same as the pin. Accordingly, no thermal stress is generated at the connection between the pin and the second conductive layer, resulting in an improved reliability of the connection.

Inventors

• 👤 Noritoshi Sugawara
• 👤 Kazuaki Satoh

Bibliographic Details