摘要 |
A method for forming a multi-layer semiconductor device (1) having a lower silicon layer (4), an intermediate silicon layer (5) within which micro-mirrors (10) are formed and an upper spacer layer (6) of silicon for spacing another component from the micro-mirrors (10). First and second etch stop layers (8, 9) of oxide act as insulation between the respective layers (4, 5, 6). In order to minimise damage to the micro-mirrors (10), the formation of the micro-mirrors (10) is left to the end of the forming process. An assembly of the lower layer (4) and the intermediate layer (5) with the fist etch stop layer (8) is formed, and the second etch stop layer (9) is than grown and patterned on the intermediate layer (5) for subsequent formation of the micro-mirrors (10). The upper layer (5) is then bonded by an annealing process to the is patterned second etch stop layer (9). After the formation of communicating bores (30) in the lower layer (4) and thinning of the fist etch stop layer (8) adjacent the micro-mirrors (10) through the communicating bores (30), openings (16) in the upper layer (6) and the micro-mirrors (10) are sequentially formed by reactive ion etching through the upper layer (6). Portions of the first and second etch stop layers (8, 9) adjacent the micro-mirrors (10) am then etched away.
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