Plasma processing method and plasma processing apparatus

• US 6,110,287 A
• Filed: 04/28/1997
• Issued: 08/29/2000
• Est. Priority Date: 03/31/1993
• Status: Expired due to Term

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited, Tokyo Electron Yamanashi Ltd. (Tokyo Electron Limited)
• Inventors: Miura, Yutaka, Iimuro, Shunichi, Tahara, Yoshifumi, Fukasawa, Kazuo, Mitano, Yoshinobu, Hosoda, Shozo, Nishikawa, Hiroshi, Arai, Izumi
• Primary Examiner(s): DANG, THI D
• Application Number:
  US08/843,129
• Time in Patent Office: 1,219 Days
• Field of Search: 156/345, 118/723 E
• US Class Current: 156/345.34
• CPC Class Codes: C23C 16/5096 Flat-bed apparatus
• CPC Class Codes: H01J 37/3244 Gas supply means
• CPC Class Codes: H01L 21/67069 for drying etching

Abstract

A plasma processing method in which a high-frequency power is supplied to a processing chamber in which an object to be processed is mounted, thereby producing a plasma in the processing chamber, and the object is processed in an atmosphere of the plasma, wherein the high-frequency power is subjected to modulation by a low-frequency power. In one embodiment a plasma is produced in a processing chamber by using an electric power with a direction of current changed with passing of time, and the object to be processed is processed in an atmosphere of the plasma, wherein a power having a basic frequency is subjected to frequency modulation with a frequency equal to n-times (n=an integer) the basic frequency. In a plasma processing apparatus of the invention, while a process gas is supplied to a processing chamber via a first gas introducing hole formed in an electrode, an object to be processed, which is held on an opposed electrode, is subjected to plasma processing. There is provided a resistance applying [means for applying] apply resistance to the process gas flowing to the processing chamber via the gas introducing hole from the gas introducing means such that a plasma discharge is prevented from occurring in the gas introducing means when a process pressure in the processing chamber is set at 0.5 Torr or less.

Claims

1. A plasma processing apparatus, comprising:

a processing chamber;

a first electrode having gas introducing means;

a first gas introducing hole formed in said first electrode;

a second electrode provided opposite said first electrode;

a resistance applying means having a resistance plate provided with a second gas introducing hole formed therein,

wherein a process gas is supplied to said processing chamber via said first gas introducing hole formed in said first electrode,

an object to be processed held on said second electrode is subjected to plasma processing,

said resistance applying means applies resistance to the process gas flowing to said processing chamber via said first gas introducing hole from said gas introducing means such that a plasma discharge is prevented from occurring under a condition of a process pressure less than 0.5 Torr in said processing chamber,

said resistance plate is provided between said first electrode and said gas introducing means, and

the resistance to the flowing process gas is varied by varying at least a thickness of said resistance plate, a pitch of one of said first and second gas introducing holes, and a diameter of one of said first and second gas introducing holes.

2. A plasma processing apparatus, comprising:

a processing chamber;

first and second electrodes provided in the processing chamber and facing each other to form a plasma processing space therebetween, the first electrode supporting an object to be processed thereon, and the second electrode having a plurality of first gas introducing holes;

process gas introducing means having a chamber communicating with the plasma processing space through the first gas introducing holes in the second electrode;

gas supply means for supplying a process gas into the chamber in the process gas introducing means, so that the process gas flows into the plasma processing space through the first gas introducing holes;

means for evacuating the processing chamber so that a gas pressure in the plasma processing space allows plasma to be formed in the plasma processing space;

means for generating plasma in the plasma processing space; and

resistance applying means provided between the chamber of the process gas introducing means and the second electrode for applying resistance to the process gas flowing to the plasma processing space from the chamber thereby increasing a gas pressure in the chamber to be greater than the gas pressure in the plasma processing space so as to prevent generation of plasma in the chamber,

wherein said resistance applying means has a resistance plate electrically and thermally connected to the second electrode and a plurality of second gas introducing holes formed in the resistance plate so that the chamber communicates with the first gas introducing holes through the second gas introducing holes,

said second gas introducing holes are respectively coaxially aligned with the corresponding first gas introducing holes, and each of the second gas introducing holes has a larger diameter than that of each of the first gas introducing holes, and

a thickness of said resistance plate, a pitch and a diameters of at least one of the second gas introducing holes and the first gas introducing holes are changed to vary the resistance of the flowing process gas.