Mechanical Characterization of Ultra-Thin, Flexible Glass Substrates for RF Applications

Glass has been shown to be a capable core substrate material for high-frequency applications. In this article, we examine the capabilities of ultra-thin glass as a material that can be used for high-frequency flexible applications. The two stack-ups discussed in the work presented are 60
$\mu \text{m}$
in total thickness with a core glass substrate (Schott AF32) of 30
$\mu \text{m}$
thickness. One stack-up uses 15
$\mu \text{m}$
JSR GT-N01 as a buildup dielectric on each side of the glass and the other uses 15
$\mu \text{m}$
Taiyo Ink photo imageable dielectric (PID). Both stack-ups have been characterized to 110 GHz and have shown to have comparable performance to materials used in this frequency range. This work then focuses on the mechanical characterization of these stack-ups using free arc bending. The free arc bending tests show that both ultra-thin glass stack-ups are suitable for bending applications as the tested samples can bend to a panel separation below 33% of the sample’s total length. This article concludes that the ultra-thin glass stack-ups are suitable for high-frequency flexible applications because the electrical performance is comparable to other high-frequency rigid materials while exhibiting their flexible capabilities.