Silicon micromachining using a high-density plasma source

Abstract

Dry etching of Si is critical in satisfying the demands of themicromachining industry. The micro-electro-mechanical systems (MEMS) communityrequires etches capable of high aspect ratios, vertical profiles, good featuresize control and etch uniformity along with high throughput to satisfyproduction requirements. Surface technology systems' (STS's) high-densityinductively coupled plasma (ICP) etch tool enables a wide range ofapplications to be realized whilst optimizing the above parameters.Components manufactured from Si using an STS ICP include accelerometers andgyroscopes for military, automotive and domestic applications. STS's advancedsilicon etch (ASETM) has also allowed the first generation ofMEMS-based optical switches and attenuators to reach the marketplace. Inaddition, a specialized application for fabricating the next generationphotolithography exposure masks has been optimized for 200 mm diameter wafers,to depths of ~750 µm.Where the profile is not critical, etch rates of greater than8 µm min-1 have been realized to replace previous methods such as wetetching. This is also the case for printer applications. Specializedapplications that require etching down to pyrex or oxide often result in theloss of feature size control at the interface; this is an industry wideproblem. STS have developed a technique to address this.The rapid progression of the industry has led to development of the STS ICP etch tool,as well as the process.