| 摘要 |
A tamper resistant structure has a pattern which covers portions of an IC but exposes other portions of the IC so that etching away the tamper resistant structure destroys the exposed portions. The IC can not be easily disassembled and reverse engineered because the tamper resistant structure hides active circuitry and removing the tamper resistant structure destroys active circuitry. One embodiment of the tamper resistant structure includes a metal layer and a cap layer. The cap layer typically includes material that is difficult to remove, such as silicon carbide, silicon nitride, or aluminum nitride. The metal layer typically includes a chemically resistant material such as gold or platinum. A bonding layer of nickel-vanadium alloy, titanium-tungsten alloy, chromium, or molybdenum, may be used to provide stronger bonds between layers. Some embodiments provide an anti-corrosion seals for bonding pads in addition to the tamper residant structure. The seals and tamper resistant structures are formed using the same materials and processing steps. The choice of pattern which covers and exposes different portions of the IC can be random or tailored to the active circuitry. The pattern can be the same for every chip or different for every chip formed from a wafer. |
