Patent ID: 7449284

Claim:
A method for fabricating mechanical deflection structures from bonding substrates, the method comprising: providing a bonded substrate structure, the bonded substrate structure comprising a first substrate having a first thickness and a first face, the bonded substrate structure comprising a second substrate having a second thickness and a second face, wherein the first face is bonded to the second face, at least the first substrate or at least the second substrate having a buried alignment mark on either the first face or the second face; applying a layer of photomasking material overlying a backside surface of the first substrate; illuminating electromagnetic radiation through the layer of photomasking material and through a portion of the first thickness, thereby scattering the electromagnetic radiation off of the buried alignment mark; detecting an indication of the buried alignment mark using a signal associated with a portion of the electromagnetic radiation, wherein the signal traverses through the portion of the first thickness and through the layer of photomasking material; aligning a pattern on a reticle to the layer of photomasking to an accuracy of 200 nanometers and less with respect to the buried alignment mark based on the detected indication; and exposing a portion of the layer of photomasking material once the pattern has been aligned using the buried alignment mark to form a second alignment mark on the backside surface of the first substrate.