| 摘要 |
A chemical mixture etches chemically different materials, layers, or films on the surface of a semiconductor wafer or other workpiece at approximately the same rate. The different layers may include, for example, a first material, having a first chemical composition, encapsulated within or sandwiched between one or more materials having chemical compositions different from the first material. For example, a TiN layer may be encapsulated within or sandwiched between two or more TEOS layers. By etching away the different layers at approximately the same rate, undercutting of the encapsulated or sandwiched layer is substantially or entirely prevented. Flaking, liftoff, and similar defects are avoided.
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