3D integrated circuits, a key technology for faster computing, is enabled by temporary wafer bonding. Here, spin-on adhesives attach device wafers to supportive carriers so they can be ground to tens of microns thick. Then, they can have vertical connections called vias etched and metallized into them to allow stacked wafers to communicate. Most tapes, waxes and other adhesives previously used for wafer thinning are inadequate for this application, so higher specification products must be used. These can be thermoplastic or UV cured spin-on polymers. For most people how the marvels that electronic devices bring are achieved is a mystery, though it's clear that ever more is being crammed into surprisingly small packages. However, there are physical limits to continually increasing computing power, for example in delays in propagating digital signals through on-chip wiring that occur as integrated circuits (ICs) shrink further.