摘要 |
<p>A method and apparatus is disclosed for controlling the pressure of reaction chamber (106) in wafer processing equipment. The disclosed apparatus and method uses a ballast port (150a, 150b) for inserting gas into the evacuation system (130), thereby controlling the pressure in the reaction chamber (106). The disclosed apparatus and method further uses estimation curves to estimate the desired position of a controlled gate valve (124) which is located between the reaction chamber (106) and turbo pump (126). The disclosed apparatus and method further introduces process gases at higher rate than set point levels to reduce the transition time or stabilization time required when raising the pressure in the reaction chamber (106).</p> |