| 摘要 |
PURPOSE:To improve the yield of an air bridge by covering lower layer wirings with an insulating material which is softened at high temperature of 500 deg.C or lower, forming upper layer wirings, and removing by gas plasma the insulating material, thereby eliminating the restriction in the steps due to the stepwise disconnection and weakness in mechanical strength. CONSTITUTION:Upper layer wirings 22 cross lower layer wirings 21 through an insulating film 23 having a smooth section. The film 23 is etched by gas plasma which does not affect the influence to a substrate or wiring metal, thereby foring an air bridge in noncontact. After lower layer wiring metal 31 is formed by normal photolithographic and lift-off methods, a photoresist (OFPR-800) is formed on the entire substrate. A resist film 33 is allowed to remain only on the crossover of the upper and lower layer wirings forming the air bridge by the lithography and the peripheral regions, and baked at 200 deg.C for 20min. Then, upper layer wirings 32 are formed by the method equivalent to the lower layer wirings. The film 33 of air bridge structure is removed by plasma etching with oxygen gas an air bridge. |
