Method of operating ion source and ion implanting apparatus

• US 20070089833A1
• Filed: 10/19/2006
• Published: 04/26/2007
• Est. Priority Date: 10/20/2005
• Status: Active Grant

• Current Assignee: Nissin Ion Equipment Co., LTD. (Sumitomo Corporation)
• Original Assignee: Nissin Ion Equipment Co., LTD. (Sumitomo Corporation)
• Inventors: Ando, Yasunori, Matsuda, Yasuhiro, Dohi, Syojiro, Inouchi, Yutaka
• Granted Patent: US 8,147,705 B2
• Time in Patent Office: Days
• US Class Current: 156/345.400
• CPC Class Codes: C23C 14/48 Ion implantation
• CPC Class Codes: H01J 2237/082 Electron beam
• CPC Class Codes: H01J 37/08 Ion sources; Ion guns

Abstract

When an ion beam 4 is to be extracted from an ion source 2 by using a gas containing boron trifluoride as an ion source gas 50 for supplying the gas into a plasma chamber 20 for the ion source 2, a bias voltage V_B of a plasma electrode 31 with respect to the plasma chamber 20 for the ion source 2 is set to be positive by a bias circuit 64.

Claims

1. A method of operating an ion source which comprises a plasma chamber into which an ion source gas is introduced, and which is used for internally producing a plasma, an ionizing member for ionizing the ion source gas in said plasma chamber by means of electron impact to produce a plasma, an extraction electrode system which is disposed in a vicinity of an opening portion of said plasma chamber, which extracts an ion beam from the plasma, and which has one or more electrodes, an insulating member for electrically insulating a plasma electrode from said plasma chamber, said plasma electrode being an electrode which is closest to the plasma among said electrodes constituting said extraction electrode system, and a plurality of magnets which form a cusp magnetic field in a vicinity of an inner wall of said plasma chamber, said method comprising-a step of:

when the ion beam is to be extracted by using a gas containing boron trifluoride (BF₃) as the ion source gas, setting a bias voltage of said plasma electrode with respect to said plasma chamber to be positive.

2. A method of operating an ion source according to claim 1, further comprising a step of:

when the ion beam is to be extracted by using a gas containing phosphine (PH₃) as the ion source gas, setting the bias voltage of said plasma electrode with respect to said plasma chamber to be negative.

6. A method of operating an ion source according to claim 1, wherein when the gas containing boron trifluoride is used as the ion source gas, the bias voltage is set in a range of 0<

V_B≦

15 [V] wherein V_B is the bias voltage.

7. A method of operating an ion source according to claim 2, wherein when the gas containing phosphine (PH₃) is used as the ion source gas, the bias voltage is set in a range of −

30≦

V_B<

0 wherein V_B is the bias voltage.

3. An ion implanting apparatus having a configuration in which ion implantation is performed by causing an ion beam extracted from an ion source to be incident on a substrate, wherein said apparatus comprises:

an ion source having;

a plasma chamber into which an ion source gas is introduced, and which is used for internally producing a plasma;

an ionizing member for ionizing the ion source gas in said plasma chamber by means of electron impact to produce a plasma;

an extraction electrode system which is disposed in a vicinity of an opening portion of said plasma chamber, which extracts an ion beam from the plasma, and which has one or more electrodes;

an insulating member for electrically insulating a plasma electrode from said plasma chamber, said plasma electrode being an electrode which is closest to the plasma among said electrodes constituting said extraction electrode system; and

a plurality of magnets which form a cusp magnetic field in a vicinity of an inner wall of said plasma chamber;

a gas supplying unit for supplying an ion source gas containing boron trifluoride (BF₃) into said plasma chamber of said ion source; and

a biasing unit in which, when the ion beam is to be extracted by using a gas containing boron trifluoride as the ion source gas, a bias voltage of said plasma electrode with respect to said plasma chamber is set to be positive.

5. An ion implanting apparatus according to claim 3, wherein said apparatus further comprises a mass separating unit for performing mass separation on the ion beam which is extracted from said ion source, between said ion source and a holding portion for said substrate.

8. An ion implanting apparatus according to claim 3, wherein when the gas containing boron trifluoride is used as the ion source gas, the bias voltage is set in a range of 0<

V_B≦

15 [V] wherein V_B is the bias voltage.

4. An ion implanting apparatus having a configuration in which ion implantation is performed by causing an ion beam extracted from an ion source to be incident on a substrate, wherein said apparatus comprises:

an ion source having;

a plasma chamber into which an ion source gas is introduced, and which is used for internally producing a plasma;

an ionizing member for ionizing the ion source gas in said plasma chamber by means of electron impact to produce a plasma;

an extraction electrode system which is disposed in a vicinity of an opening portion of said plasma chamber, which extracts an ion beam from the plasma, and which has one or more electrodes;

an insulating member for electrically insulating a plasma electrode from said plasma chamber, said plasma electrode being an electrode which is closest to the plasma among said electrodes constituting said extraction electrode system; and

a plurality of magnets which form a cusp magnetic field in a vicinity of an inner wall of said plasma chamber;

a gas supplying unit for switchingly supplying an ion source gas containing boron trifluoride (BF₃), and an ion source gas containing phosphine (PH₃) into said plasma chamber of said ion source;

a biasing unit in which, when the ion beam is to be extracted from said ion source, a bias voltage of said plasma electrode with respect to said plasma chamber is switchable between a positive voltage and a negative voltage; and

a controller for controlling said gas supplying unit and said biasing unit to, when the ion source gas containing boron trifluoride is to be supplied into said plasma chamber, set the bias voltage to be positive, and, when the ion source gas containing phosphine is to be supplied into said plasma chamber, set the bias voltage to be negative.

9. An ion implanting apparatus according to claim 4, wherein when the gas containing boron trifluoride is used as the ion source gas, the bias voltage is set in a range of 0<

V_B≦

15 [V] wherein V_B is the bias voltage, and when the gas containing phosphine (PH₃) is used as the ion source gas, the bias voltage is set in a range of −

30≦

V_B<

0 wherein V_B is the bias voltage.

10. An ion implanting apparatus according to claim 4, wherein said apparatus further comprises a mass separating unit for performing mass separation on the ion beam which is extracted from said ion source, between said ion source and a holding portion for said substrate.