Intel seems pretty excited about glass substrates
 

These days when we talk about what's next for chip design, we focus on things like cramming in more cores, increasing clock speeds, shrinking transistors and 3D stacking. We rarely think about the package substrate, which holds and connects those components. Today Intel, in the midst of its reinvention as a foundry company, has announced it's made a major breakthrough in substrate materials—and it's all about glass.

https://www.engadget.com/intel-seems...3.html?src=rss