| 摘要 |
<p>A silicon substrate having a silicon dioxide bird's head is provided. A thermal oxide layer is grown on the exposed silicon surface. A layer, e.g., 4000 A DEG , of phosphogermanosilicate glass is deposited on the thermal oxide and on the silicon dioxide bird's head. The structure is heated to 950 DEG C, causing a reflow of the glass which results in a planar surface. The thermal oxide and the phosphogermanosilicate glass are then wet etched at the same rate with a solution of hydrofluoric acid, ammonium fluoride, and deionized water. The wet etch is terminated when the exposed silicon surface is reached, resulting in a smooth surface as defined by the planar reflow surface. Other embodiments are disclosed.</p> |
