Long life incandescent switching system
Method for controlling plasma etching rates
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Etching method and etching apparatus Patent #: 4931135
ApplicationNo. 714231 filed on 06/12/1991
US Classes:156/345.44, Electrically coupled to a power supply or matching circuit118/723E, Having glow discharge electrodes (e.g., DC, AC, RF, etc.)204/298.06, Triode, tetrode, auxiliary electrode or biased workpiece204/298.34, Auxiliary electrode, bias means or specified power supply315/111.51Induction type
ExaminersPrimary: Simmons, David A.
Assistant: Goudreau, George
Attorney, Agent or Firm
International ClassH01L 021/00
Foreign Application Priority Data1990-06-15 JP
AbstractA plasma generating apparatus comprising a transformer including a primary winding connected to a high frequency power source and a secondary winding having two end terminals and a plurality of tap terminals connected between the end terminals, the transformer being adapted to deliver first and second high frequency electric powers with a phase difference of 180° from the end terminals, upper and lower electrodes disposed in a vacuum chamber so as to be opposed at a distance from each other and supplied with the first and second high frequency powers, respectively, and a power ratio selector for switching the tap terminals to select the ratio between the first and second high frequency powers supplied to the electrodes, wherein a to-be-processed object placed on the lower electrode is processed by means of plasma formed between the electrodes.