| 摘要 |
PURPOSE:To prevent over-etching without requiring any special attachment by controlling etching time based on the change in the internal pressure of an etching chamber in performing etching of Al type films by a C-contg. gas. CONSTITUTION:An Si substrate deposited with an Al film is installed in a plasma etching device and, for example, gaseous CCl4 is introduced, after which electric charge is caused and etching is performed. After the start of the charging, the pressure in the etching chamber ascends once and attains a peak value, after which it drops and shows steady value. The rate DELTAp of the pressure drop of the initial period is proportional to etching rates. Hence, this relation is registered before hand in a memory, and film thickness data are actually measured by every treatment lot and are inputted to a microcomputer. When the pressure attains the steady state after the start of etching, the DELTAp value is fed automaticaly to the computer, by which the required time is calculated and when the etching is carried out by that time, the device stops automatically. |
