Ion implantation
First Claim
1. A method of implanting ions in a substrate using an ion beam having cross-sectional dimensions smaller that the substrate comprising the steps of:
- (a) establishing a stable ion beam with the substrate clear of the ion beam;
(b) implanting the substrate by causing relative motion between the ion beam and the substrate such that the ion beam traverses the substrate along at least one path;
(c) monitoring the ion beam for instabilities during step (b);
(d) upon detecting an ion beam instability, switching off the ion beam as the relative motion continues to leave an unimplanted portion of the path;
(e) recording an off position corresponding to the ion beam'"'"'s position relative to the substrate when the ion beam is switched off in step (d);
(f) establishing a stable ion beam once more; and
(g) continuing to implant the substrate by causing relative motion between the ion beam and the substrate along the unimplanted portion of the path.
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Accused Products
Abstract
This invention relates to a method of implanting ions in a substrate using an ion beam where instabilities in the ion beam may be present and to an ion implanter for use with such a method. This invention also relates to an ion source for generating an ion beam that can be switched off rapidly. In essence, the invention provides a method of implanting ions comprising switching off the ion beam when an instability has been detected whilst continuing motion of the substrate relative to the ion beam to leave an unimplanted portion of a scan line across the substrate, establishing a stable ion beam once more and finishing the scan line by implanting the unimplanted portion of the path.
47 Citations
30 Claims
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1. A method of implanting ions in a substrate using an ion beam having cross-sectional dimensions smaller that the substrate comprising the steps of:
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(a) establishing a stable ion beam with the substrate clear of the ion beam;
(b) implanting the substrate by causing relative motion between the ion beam and the substrate such that the ion beam traverses the substrate along at least one path;
(c) monitoring the ion beam for instabilities during step (b);
(d) upon detecting an ion beam instability, switching off the ion beam as the relative motion continues to leave an unimplanted portion of the path;
(e) recording an off position corresponding to the ion beam'"'"'s position relative to the substrate when the ion beam is switched off in step (d);
(f) establishing a stable ion beam once more; and
(g) continuing to implant the substrate by causing relative motion between the ion beam and the substrate along the unimplanted portion of the path. - View Dependent Claims (2, 3, 4, 5, 6, 7, 30)
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8. A method of implanting ions in a substrate held in a substrate holder moveable bidirectionally along a first axis of translation, the method comprising the steps of:
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(a) establishing a stable ion beam having cross-sectional dimensions smaller than the substrate with the ion beam clear of the substrate in a start position adjacent the substrate along the first axis;
(b) implanting the substrate by moving the substrate holder along the first axis such that the ion beam transverses the substrate along a first scan line and continues until clear of the substrate;
(c) causing relative motion between the ion beam and the substrate holder along a second axis;
(d) repeating steps (b) and (c) to implant a series of scan lines across the substrate;
(e) monitoring the ion beam during implantation in step (b) and as repeated according to step (d);
(f) upon detecting an ion beam instability, switching off the ion beam as the relative motion continues to leave an unimplanted portion of the scan line;
(g) recording an off position corresponding to the position of the substrate holder when the ion beam is switched off in step (f);
(h) establishing a stable ion beam once more;
(i) completing implantation of the scan line by moving the substrate holder along the first axis so that the ion beam scans over the unimplanted portion of the scan line; and
(j) completing implantation of the substrate by repeating steps (b) and (c) to complete the series of scan lines across the substrate. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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16. An ion implanter controller for an ion implanter operable to generate an ion beam for implanting into a substrate wherein the ion beam has cross-sectional dimensions smaller than the substrate, the controller comprising:
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ion beam switching means operable to cause the ion beam to switch on and off;
scanning means operable to cause relative motion between the ion beam and the substrate such that the ion beam traverses the substrate along at least one path;
ion beam monitoring means operable to receive a signal indicative of the ion beam flux and to detect instabilities in the ion beam therefrom during said relative motion; and
indexing means operable to determine the position of the ion beam relative to the substrate during said relative motion;
wherein the controller is arranged such that;
the ion beam switching means is operable to cause the ion beam to switch off during the relative motion when the ion beam monitoring means detects an instability in the ion beam to leave an unimplanted portion of the path;
the indexing means records an off position of the ion beam relative to the substrate when the ion beam is switched off;
the ion beam switching means is operable to cause the ion beam to switch on once more; and
the scanning means is operable to cause relative motion between the ion beam and the substrate such that the ion beam traverses the substrate along the unimplanted part of the path. - View Dependent Claims (17, 18, 19, 20)
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21. An ion source for an ion implanter comprising:
- a cathode, an anode, biasing means for biasing the anode relative to the cathode, a first switch, and a first electrical path connecting anode to cathode via the biasing means and the first switch arranged in series, wherein the first switch is operable to make or break the first electrical path.
- View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29)
Specification