Helicon wave plasma processing apparatus

• US 6,096,160 A
• Filed: 04/16/1997
• Issued: 08/01/2000
• Est. Priority Date: 02/10/1994
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Kadomura, Shingo
• Primary Examiner(s): Dang, Thi
• Assistant Examiner(s): ALEJANDRO MULERO, LUZ L
• Application Number:
  US08/840,325
• Time in Patent Office: 1,203 Days
• Field of Search: 118/723 AN, 118/723 I, 118/723 IR, 118/723 MR, 118/723 MA, 156/345, 204/298.16, 204/298.37, 438/711, 438/714, 438/732, 216/68, 216/70, 315/111.41, 315/111.51
• US Class Current: 156/345.49
• CPC Class Codes: C23F 4/00 Processes for removing metallic material from surfaces, not provided for in group C23F1/00 or C23F3/00
• CPC Class Codes: H01J 2237/3345 anisotropy
• CPC Class Codes: H01J 2237/3346 Selectivity
• CPC Class Codes: H01J 37/321 the radio frequency energy being inductively coupled to the plasma
• CPC Class Codes: H01J 37/3211 Antennas, e.g. particular shapes of coils
• CPC Class Codes: H01J 37/32422 Arrangement for selecting ions or species in the plasma
• CPC Class Codes: H01L 21/3213 Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer

Abstract

Controlling ion/radical ratio and monoatomic/polyatomic radical ratio in a process plasma provides improved processing performance during inductively-coupled plasma and/or helicon wave plasma processing of substrate materials. In a plasma processing method employing inductively coupled plasma, high frequency current to a high frequency antenna is intermittently supplied in a controlled manner to control the state of gas dissociation to promote formation of polyatomic radicals. In a plasma processing method employing helicon wave plasma, current supplied to a magnetic field generator is intermittently supplied in a controlled manner to promote formation of ions. In a preferred method, both the high frequency current and magnetic field generating current are varied in a controlled manner to provide a variable plasma composition, i.e., radical rich plasma or ion-rich plasma, as desired, for improved plasma processing, especially improved selective anisotropic dry etching at high etch rate.

Claims

1. A plasma apparatus, comprising:

a vacuum vessel for accommodating a substrate therein, said vacuum vessel having a wall,

a portion of said wall of said vacuum vessel being formed of an electrically non-conductive material,

a high-frequency antenna placed around the portion of the wall of the vacuum vessel formed of the electrically non-conductive material,

magnetic field generating means place on an outer periphery of said high-frequency antenna for generating a magnetic field,

magnetic field control means for switching between generation and extinction of the magnetic field by said magnetic field generating means so as to switch between a helicon wave plasma and an inductively coupled plasma in said vacuum vessel,

high-frequency electrical field control means for high-speed switching between supply and interruption of a high-frequency current to said high-frequency antenna, and

means for generating a helicon-wave plasma within said vacuum vessel.

2. A plasma apparatus, comprising:

a vacuum vessel for accommodating a substrate therein, said vacuum vessel having a wall, a portion of said wall of said vacuum vessel being formed of an electrically non-conductive material,

a high-frequency antenna placed around the portion of said wall of said vacuum vessel formed of the electrically non-conductive material,

magnetic field generating means placed on an outer periphery of said high-frequency antenna for generating a magnetic field,

magnetic field control means for switching between generation and extinction of the magnetic field by said magnetic field generating means,

means for generating a helicon-wave plasma within said vacuum vessel.

3. The plasma apparatus as claimed in claim 2, wherein said magnetic field generating means is a solenoid coil and wherein said magnetic field controlling means controls current supply to said solenoid coil for switching between generation and extinction of the magnetic field.

4. The plasma apparatus as claimed in claim 2, further comprising

high-frequency electrical field control means for high-speed switching between supply and interruption of the high-frequency current to said high-frequency antenna,

means for generating a helicon-wave plasma within said vacuum vessel.

5. A plasma apparatus, comprising:

a vacuum processing chamber, a bell jar within said vacuum processing chamber for accommodating a substrate therein, said bell jar having a wall, said vacuum processing chamber including an evacuation port and a gas supply duct,

said wall of said vacuum vessel being formed of an electrically non-conductive material,

a substrate stage of electrically conductive material in said vacuum processing chamber, said substrate stage being electrically insulated from walls said processing chamber,

a cooling pipe connected to said substrate stage,

a radio frequency power source connected to said substrate stage,

a matching network connected between said radio frequency power source and said substrate stage,

a high-frequency loop antenna placed around the portion of the wall of the vacuum vessel formed of the electrically non-conductive material, said high-frequency loop antenna having upper and lower loops connected to cause current flow in mutually opposite directions,

magnetic field generating means place on an outer periphery of said high-frequency antenna for generating a magnetic field, said magnetic field generating means including a solenoid coil,

means for generating an auxiliary magnetic field including one of a magnet and a solenoid,

magnetic field control means for switching between generation and extinction of the magnetic field by said magnetic field generating means, said magnetic field control means being effective to switch between a helicon wave plasma and an inductively coupled plasma within said vacuum processing chamber;

an impedance matching network connected between said high-frequency electrical field control means and said high-frequency antenna,

said apparatus being operable to generate a helicon-wave plasma within said bell jar upon operation of said magnetic field generating means, said apparatus generating an inductively coupled plasma during non-operation of said magnetic field generating means.

6. A plasma apparatus, comprising:

a vacuum vessel for accommodating a substrate therein, said vacuum vessel having a wall, a portion of said wall of said vacuum vessel being formed of an electrically non-conductive material, said vacuum vessel including an evacuating duct,

an evacuating system connected to said evacuating duct of said vacuum vessel,

an electrically conductive substrate stage in said vacuum vessel electrically isolated from said wall,

a matching network connected to said electrically conductive substrate stage,

a radio frequency power source connected to said matching network to supply a substrate bias to said substrate stage,

a high-frequency multi-turn antenna placed around the portion of the wall of the vacuum vessel formed of the electrically non-conductive material,

high-frequency electrical field control means for high-speed switching between supply and interruption of a high-frequency current to said high-frequency antenna, said high-frequency electrical field control means including;

a high-frequency current source,

a pulse generating circuit connected to switch a high-frequency current from said high-frequency current source by a pulse from said pulse generating circuit, and

an impedance matching network connected between said pulse generating circuit and

said high-frequency multi-turn antenna, and a magnetic field generating means for switching between generation and extinction of a magnetic field, said magnetic field generating means including a solenoid and an electronic switch connected to selectively connect power to said solenid.

7. A plasma apparatus, comprising:

a vacuum processing chamber, a bell jar within said vacuum processing chamber for accommodating a substrate therein, said bell jar having a wall, said vacuum processing chamber including an evacuation port and a gas supply duct,

said wall of said vacuum vessel being formed of an electrically non-conductive material,

a substrate stage of electrically conductive material in said vacuum processing chamber, said substrate stage being electrically insulated from walls said processing chamber,

a cooling pipe connected to said substrate stage,

a radio frequency power source connected to said substrate stage,

a matching network connected between said radio frequency power source and said substrate stage,

a high-frequency loop antenna placed around the portion of the wall of the vacuum vessel formed of the electrically non-conductive material, said high-frequency loop antenna having upper and lower loops connected to cause current flow in mutually opposite directions,

magnetic field generating means place on an outer periphery of said high-frequency antenna for generating a magnetic field, said magnetic field generating means including one of a solenoid coil,

means for generating an auxiliary magnetic field including one of a magnet and a solenoid,

magnetic field control means for switching between generation and extinction of the magnetic field by said magnetic field generating means to switch between a helicon wave plasma and an inductively coupled plasma,

high-frequency electrical field control means for high-speed switching between supply and interruption of a high-frequency current to said high-frequency antenna, said high-frequency electrical field control means including a radio frequency power source and a pulse generating circuit connected to pulse an output of said radio frequency power source,

an impedance matching network connected between said high-frequency electrical field control means and said high-frequency antenna,

said apparatus being operable to generate a helicon-wave plasma within said bell jar.