| 摘要 |
PURPOSE: An etchant of 6a group is to improve an etching efficiency for a bottom metallic layer in a process for etching a double layer structured gate. CONSTITUTION: An etchant of 6a group comprises 10 to 13% by weight of Ce(NH4)x(NO3)y, wherein x exceeds zero, and y exceeds zero; 4 to 6% by weight of HClO4; and 1 to 3% by weight of CH3COOH, alternatively Ce(NH4)x(NO3)y, wherein x exceeds zero and y exceeds zero, being contained by 11 to 13% by weight, HClO4 being contained by 4 to 5% by weight, CH3COOH being contained by 1 to 2% by weight, and x is 2 and y is 6. Using the etchant, a Cr layer is selectively etched and the remaining chemical components after etching does not nearly exist, so that the Cr layer being directly etched immediately after an Al alloy layer is etched and therefrom a photoresist is stripped off, thus to eliminate a hard baking process and an ashing process.
|
