Introduction
A computer chip's purpose is to transmit information, in the form of small electric signals, from place to place. The chips themselves are made of a semiconducting metal, usually silicon or germanium, covered in a thin film of insulation (sand or glass). To make electric circuits for the information, tiny amounts of the insulation are removed to make a contact point where a wire can be attached. This allows the information to go to the correct point without interference from other signals on the same chip. It also allows for millions of circuits to be placed on a thumbnail-sized chip.

In the production of chips, it is important that the film of insulation be a uniform thickness, or else the chip is no good. As it turns out, a small difference in film thickness makes a big difference in the reflectivity of the film. What that means is that measuring the reflectivity of the film can tell you how thick it is. This is important to manufacturers because they can create just the right film thickness by depositing SiO2 until it reaches the correct reflectivity. A procedure such as this would cut production costs and reduce the amount of computer chip waste.

This experiment is intended to produce data on polished wafers of silicon, germanium, and a combination of the two. Data will also be taken on some experimental Simox wafers and on some Ronchi ruled reticles. Reticles are glass slides with thin parallel chrome lines deposited on them. They are used as guides in etching lines on wafers.

conclusion main page experimental setup