Simple lithographic technique for chip repairing using a light microscope

We have developed a simple lithographic technique for repairing damaged chips, even after the end of the whole fabrication process, by using simply a light microscope for lithographic definition. In the usual laboratory practice, it can happen that the fabricated chips present defects which make them useless, such as broken metallic lines, or unwanted contacts between close elements on the same layer. Repairing these defects requires that the damaged area is lithographically defined in the photoresist, so that a subsequent step of film deposition (for broken lines) or etching (for unwanted contacts) can be performed. The white illumination of a usual light microscope with a reduced field (by means of a diaphragm already present in the microscope optical path) can provide the necessary light source to expose the resist. Both spots and narrow lines (several microns wide) can be defined in the resist; we give the details of operation and show some examples from our devices. © 1999 American Vacuum Society.