Abstract: A laser ablation mask repair method. Defects (holes) are located in a dielectric mask. The surface of the mask above the defect is melted with a CO.sub.2 laser to form a depression in the surface. The depression forms a lens which diffuses ablation laser energy instead of transmitting it. Thus, the ablation laser is prevented from ablating a polymer ablation layer, because the holes are blocked and, the mask is repaired. The method may also be used to make Engineering Changes (EC) laser ablation masks.

Abstract: A method of patterning a preimidized benzophenone photoactive polymer used as a photoresist with a laser light source improves its crosslinking efficiency and reduces swelling, thereby enabling the formation of lines on the order of microns.

Abstract: Control of the local environment during pulsed laser removal of thin film circuit metallurgy is used to change the nature of the top surfaces. Interconnecting such laser treated surfaces with LCVD films results in different growth morphologies, dependent on the nature of the surface created and the debris generated during the ablation process. Flowing helium across the surface during the ablation process results in improved growth morphologies for the same laser writing conditions. A low power laser scan is used to induce metal deposition on the substrate without surface damage. This is followed by several scans at an intermediate laser power to deposit the desired thickness of metal (e.g., about 8 .mu.m). Lastly, a high power laser scan is used, either at the points of intersection between the existing metallurgy and the metal repair or across the entire deposit area. Thermal spreading or blooming is reduced by modulating the intensity of the laser source.

Abstract: A method for etching a polyimide body which involves directing U.V. radiation having a wavelength between about 240 to 400 nm. onto the body is described. The radiation is continued to be applied to the body for sufficient time to cause a direct etching of the body where the radiation impinges upon the body. The method is particularly useful where the U.V. radiation is passed through a mask located between the source of the ultraviolet radiation and the body so that a radiation pattern is projected onto the body where the direct etching takes place. The etching can be caused to produce openings having a positive slope in the radiation pattern upon the polyimide layer. The advantage of the positive slope is particularly great where a coating such as a metal layer is deposited over the remaining polyimide layer having the openings therein. The positive slope allows the complete filling of the openings.