Thinning and mounting a texas instruments 3-phase CCD

By having the ability to thin CCDs with precise control of thickness and surface quality astronomers will be able to optimize chips for specific applications. Traditional chemical etching is used to reduce subsurface damage of the silicon crystal lattice. We demonstrate a means of mechanically thinning a TI 800×800 CCD with an abrasive slurry of aluminum oxide. Using the same techniques we can replace the abrasives with a chemical solution to eliminate subsurface damage. We also demonstrate a technique of mounting the CCD which retains the high quality surface generated during thinning. This requires the backside of the chip to be bonded to a glass window which closely matches silicon’s thermal expansion properties. Thinned CCDs require backside treatment to enhance blue and UV quantum efficiency. Two methods are discussed which may be effective with this mounting system. Due to silicon’s high index of refraction in the visible spectral region up to 50 percent of the radiation incident onto a CCD can be lost to reflection. We briefly discuss the improvements to be gained from AR coating the backside.