Methods of forming tall, high-aspect ratio vias and trenches in photo-imageable materials, photoresist materials, and the like
 Simple and cost-effective methods for forming tall, high-aspect ratio structures in a material layer comprising a first layer of a image-reversal-type photo-sensitive material and a second layer of a positive-type photo-sensitive material is disclosed. The layers are formed, exposed to actinic radiation, and developed such that the formation, exposure, and development of the second layer does not substantially modify or destroy the patterns formed in the first layer. In one embodiment, the first layer is exposed to actinic radiation through a first mask comprising the complimentary image, or negative, of a desired high-aspect ratio structure. The image in the first layer is then reversed by heating to an elevated temperature and subsequently blank flood exposure of actinic radiation. A second layer of a positive type photo-sensitive material chemically compatible with the IRP layer is then formed over the first layer. The second layer is exposed to actinic radiation through a second mask comprising the positive image of the desired structure. Both layers are exposed to a developer solution to remove material from the layers, thereby completing the formation of the desired structure. 
Fujitsu Limited
G G
G03F G03F
inventional inventional
William Tai-Hua Wen-chou Vincent
Chou Wang