3-DIMENSIONAL PATTERNING TECHNOLOGY FOR THE FABRICATION OF COMPLEX MICRO-COMPONENTS

Virtually all patterning steps in the semiconductor industry make use of resist, a radiation-sensitive film. Masking this film before exposu re to the radiation, or alternatively by direct writing with a radiati on beam, followed by development, leaves a pattern of resist. This res ist pattern is then itself used as a mask for subsequent pattern trans fer via, for example, etching, impurity implantation or deposition. In the micro-electronics industry, all transistors and other active comp onents, metallizations, interconnects and dielectrics are defined in t his way. Features of sub-micrometre size are readily achieved across w afers of 6'' (0.15m) diameter Ultra-violet (UV) light is the most comm on radiation used and resists sensitive to UV are termed photoresists. Whilst the technology has developed over the years to provide good tw o-dimensional control, the third dimension (perpendicular to the surfa ce) is essentially fixed at one value, for example, uniform etch depth , implant depth, or metallization thickness. In recent years, with the advent of micro-optics and micro-engineering, interest in three-dimen sional patterning has grown, and effort has been directed towards exte nding the technology to provide true photo-sculpting. This paper descr ibes the 3-D patterning technology developed at GEC-Marconi Infra-Red Limited over the past six years.