IP Library Granted Patent US 9,984,855
Granted Patent B2
US 9,984,855 · App. 12/948,309 · Granted May 29, 2018

Implementation of co-gases for germanium and boron ion implants

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Quick Facts
Patent No.
US 9,984,855
App. No.
12/948,309
Granted
May 29, 2018
Kind
B2
Abstract

An ion implantation system for improving performance and extending lifetime of an ion source is disclosed. A fluorine-containing dopant gas source is introduced into the ion chamber along with one or more co-gases. The one or more co-gases can include hydrogen or krypton. The co-gases mitigate the effects caused by free fluorine ions in the ion source chamber which lead to ion source failure.

Claims (27)

1. An ion implantation system for improving performance and extending lifetime of an ion source in an ion implanter comprising:

an ion source assembly comprising a dopant gas controller, a co-gas controller, and an ion source chamber, the dopant gas controller operatively controlling the rate and flow of a fluorine-containing dopant gas source into the ion source chamber, and the co-gas controller operatively controlling the rate and flow of a co-gas into the ion source chamber, wherein the dopant gas controller and the co-gas controller are configured to operatively control a combined rate and flow of the fluorine-containing dopant gas and the co-gas to limit a pressure within the ion source chamber, and wherein the co-gas controller is further configured to adjust the rate and flow of the co-gas into the ion source chamber during operation of the ion implantation system to achieve a maximum beam current of an ion beam formed therein, wherein the co-gas controller is configured to incrementally increase the flow of the co-gas into the ion source chamber until the beam current begins to decrease, thereby establishing a threshold co-gas flow, and to further validate the beam current based on a mass spectral analysis performed on the ion beam and a comparison of a measured reduction in an undesired gas associated with the fluorine-containing dopant gas and a measured increase in a resultant gas formed after a reaction of the fluorine-containing dopant gas with the co-gas;

a beam line assembly that receives the ion beam from the ion source and processes the ion beam; and

a target location that receives the ion beam from the beam line assembly.

2. The system of claim 1 , wherein the co-gas controller releases the co-gas from one or more co-gas sources into the ion source chamber.

3. The system of claim 2 , wherein the co-gas and the dopant gas are released into the ion source chamber simultaneously.

4. The system of claim 2 , wherein the co-gas and the dopant gas are released into the ion source chamber sequentially.

5. The system of claim 1 , wherein the fluorine-containing dopant gas source comprises one or more of boron trifluoride, germanium tetrafluoride, phosphorous trifluoride, or silicon tetrafluoride.

6. The system of claim 1 , wherein the co-gas comprises hydrogen.

7. The system of claim 6 , wherein the co-gas reacts with the fluorine-containing dopant gas to form hydrogen fluoride.

8. The system of claim 7 , wherein the co-gas further comprises krypton.

9. An apparatus for improving performance of an ion source in an ion implanter comprising:

a dopant gas controller for introducing a dopant gas into the ion source chamber, the dopant gas comprising a fluorine-containing gas; and

a co-gas controller for introducing at least one co-gas into the ion source chamber, the co-gas reacting with the fluorine in the dopant gas to improve the performance of the ion source, wherein the dopant gas controller and the co-gas controller are configured to operatively control a combined rate and flow of the dopant gas and the co-gas to limit a pressure within the ion source chamber, and wherein the co-gas controller is further configured to adjust the rate and flow of the co-gas into the ion source chamber during operation of the ion source chamber to achieve a maximum beam current of an ion beam formed therein, wherein the co-gas controller is configured to incrementally increase the flow of the co-gas into the ion source chamber until the beam current begins to decrease, thereby establishing a threshold co-gas flow, and to further validate the beam current based on a mass spectral analysis performed on the ion beam and a comparison of a measured reduction in an undesired gas associated with the fluorine-containing gas and a measured increase in a resultant gas formed after a reaction of the fluorine-containing gas with the co-gas.

10. The apparatus of claim 9 , wherein the at least one co-gas reacts with the fluorine-containing dopant gas to produce hydrogen fluoride.

11. The apparatus of claim 9 , wherein the co-gas comprises hydrogen.

12. The apparatus of claim 11 , wherein the co-gas further comprises krypton.

13. A method for improving productivity of an ion source including an ion source chamber, the method comprising:

introducing a fluorine-containing dopant gas to the ion source chamber for generating a plasma therein;

introducing at least one co-gas to the ion source chamber, the co-gas being operative to react with fluorine ions in the plasma to reduce formation of contaminants in the ion source chamber, wherein introducing the fluorine-containing dopant gas and the at least one co-gas to the ion source chamber limits a pressure within the ion source chamber by controlling a combined rate and flow of the fluorine-containing dopant gas and the co-gas, and wherein the rate and flow of the co-gas into the ion source chamber is adjusted during operation of the ion source chamber, wherein the flow of the co-gas into the ion source chamber is incrementally increased until a beam current of an ion beam formed therein begins to decrease, thereby defining a maximum beam current of the ion beam and establishing a threshold co-gas flow, and wherein the beam current is further validated based on a mass spectral analysis performed on the ion beam and a comparison of a measured reduction in an undesired gas associated with the fluorine-containing dopant gas and a measured increase in a resultant gas formed after a reaction of the fluorine-containing dopant gas with the co-gas;

exciting the fluorine-containing dopant gas within the chamber to create a plasma of dissociated and ionized dopant and fluorine constituents; and

reacting the dissociated and ionized fluorine constituents with the at least one co-gas to reduce poisoning of the ion source chamber and increase ion source lifetime.

14. The method of claim 13 , the gas source comprising one or more of boron trifluoride, germanium tetrafluoride, phosphorous trifluoride, or silicon tetrafluoride.

15. The method of claim 14 , wherein the co-gas comprises hydrogen.

16. The method of claim 15 , wherein the co-gas further comprises krypton.

17. The method of claim 15 , wherein the reacting of the dissociated and ionized fluorine constituents with the at least one co-gas comprises forming hydrogen fluoride.

18. The method of claim 13 , further comprising releasing a predetermined amount of co-gas into the ion source chamber.

Assignments (4)
RELEASE OF SECURITY INTEREST Recorded Apr 7, 2023
From: SILICON VALLEY BANK A DIVISION OF FIRST-CITIZENS BANK & TRUST COMPANY
To: AXCELIS TECHNOLOGIES, INC.
Reel/Frame 063270/0277 →
SECURITY INTEREST Recorded Jul 31, 2020
From: AXCELIS TECHNOLOGIES, INC.
To: SILICON VALLEY BANK, AS ADMINISTRATIVE AGENT
Reel/Frame 053375/0055 →
FIRST AMENDMENT TO SECURITY AGREEMENT Recorded May 10, 2011
From: AXCELIS TECHNOLOGIES, INC.
To: SILICON VALLEY BANK
Reel/Frame 026250/0524 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Dec 3, 2010
From: COLVIN, NEIL; HSIEH, TSEH-JEN
To: AXCELIS TECHNOLOGIES, INC.
Reel/Frame 025444/0262 →