Comment by Sanzig

> Also do chips in space need casing or could the wafers be just exposed on that back layer?

Even in LEO they benefit tremendously from radiation shielding, even a couple millimeters of aluminum greatly reduces the total ionizing dose. Also LEO has the issue of monatomic oxygen in the thermosphere which tends to react aggressively with the surface of anything it touches. An aluminium spacecraft structure isn't really affected, but I don't think it'd be very good for a semiconductor wafer.