Method for forming a semiconductor device and a semiconductor device formed by the method

Abstract

A method for forming a multi-layer semiconductor device ( ) having a lower silicon layer ( ), an intermediate silicon layer ( ) within which micro-mirrors ( ) are formed and an upper spacer layer ( ) of silicon for spacing another component from the micro-mirrors ( ). First and second etch stop layers ( ) of oxide act as insulation between the respective layers ( ). In order to minimize damage to the micro-mirrors ( ), the formation of the micro-mirrors ( ) is left to the end of the forming process. An assembly of the lower layer ( ) and the intermediate layer ( ) with the first etch stop layer ( ) is formed, and the second etch stop layer ( ) is then grown and patterned on the intermediate layer ( ) for subsequent formation of the micro-mirrors ( ). The upper layer ( ) is then bonded by an annealing process to the patterned second etch stop layer ( ). After the formation of communicating bores ( ) in the lower layer ( ) and thinning of the first etch stop layer ( ) adjacent the micro-mirrors ( ) through the communicating bores ( ), openings ( ) in the upper layer ( ) and the micro-mirrors ( ) are sequentially formed by reactive ion etching through the upper layer ( ). Portions of the first and second etch stop layers ( ) adjacent the micro-mirrors ( ) are then etched away.