Fluid flow control method and apparatus for an ion implanter
First Claim
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1. A system for treating one or more generally circular wafers comprising:
- a) a chamber that defines a chamber interior having a wafer support onto which one or more wafers are moved prior to treatment;
said chamber having cylindrical internal flow-defining surfaces that encircle an outer periphery of the wafer support;
b) means for inserting wafers into the chamber and placing them on the wafer support prior to treatment and removing the wafers from the chamber after they have been treated;
c) structure for venting fluid into the chamber through a first passageway and for evacuating the chamber by withdrawing fluid from the chamber through a second passageway;
d) a controller for adjusting fluid flow entering or exiting the chamber via the first and the second passageways; and
e) fluid flow distribution means mounted relative the wafer support within the chamber for providing radial fluid flow away from the cylindrical internal flow-defining surfaces to a region of the wafers during chamber venting and for providing radial fluid flow toward the cylindrical internal flow-defining surfaces from the region of the wafers during chamber evacuation to impede particle contamination of wafers within the chamber;
f) said cylindrical internal flow-defining surfaces and the flow distribution means defining a flow region through the chamber for promoting laminar fluid flow within the chamber.
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Abstract
A fluid flow control for use with a process chamber. In the disclosed embodiment, the process chamber is for ion implantation of a workpiece such as a silicon wafer and the fluid flow control is to assure the flow rates are maintained at values which are efficient in evacuating and pressurizing the chamber do not dislodge particulate contaminants from the process chamber walls. In the disclosed design, wafers are inserted into the chamber by use of a loadlock which avoids the requirement that the process chamber be cyclicly pressurized and depressurized. A diffuser plate intercepts fluid flowing into and out of the process chamber.
64 Citations
18 Claims
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1. A system for treating one or more generally circular wafers comprising:
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a) a chamber that defines a chamber interior having a wafer support onto which one or more wafers are moved prior to treatment;
said chamber having cylindrical internal flow-defining surfaces that encircle an outer periphery of the wafer support;b) means for inserting wafers into the chamber and placing them on the wafer support prior to treatment and removing the wafers from the chamber after they have been treated; c) structure for venting fluid into the chamber through a first passageway and for evacuating the chamber by withdrawing fluid from the chamber through a second passageway; d) a controller for adjusting fluid flow entering or exiting the chamber via the first and the second passageways; and e) fluid flow distribution means mounted relative the wafer support within the chamber for providing radial fluid flow away from the cylindrical internal flow-defining surfaces to a region of the wafers during chamber venting and for providing radial fluid flow toward the cylindrical internal flow-defining surfaces from the region of the wafers during chamber evacuation to impede particle contamination of wafers within the chamber; f) said cylindrical internal flow-defining surfaces and the flow distribution means defining a flow region through the chamber for promoting laminar fluid flow within the chamber. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An ion implantation system for sequentially treating workpieces comprising:
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a) an implantation chamber that defines a chamber interior into which the workpieces are moved for treatment, said chamber having an opening for inserting workpieces into the chamber prior to treatment and removing the workpieces from the chamber after they have been treated; b) a pressure chamber in fluid communication with the implantation chamber through the opening of the implantation chamber including a region bounded by a wall having a first opening for allowing a fluid to enter the pressure chamber through an inlet flow control passageway and a second opening concentric with the first opening for evacuating the pressure chamber by withdrawing fluid in the pressure chamber through an outlet flow control passageway; and c) a flow controller for controlling fluid flow entering or exiting the pressure chamber via the first and second flow control passageways to enable workpieces to be moved into and out of the pressure chamber at atmospheric pressure and moved into and removed from the implantation chamber at a pressure less than atmospheric pressure;
said controller including means for performing a cleaning cycle to cleanse contaminants from said pressure chamber by simultaneously routing pressurized fluid into the pressure chamber through the inlet flow control passageway and out the outlet flow control passageway. - View Dependent Claims (14)
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15. A method for moving silicon wafers through a loadlock chamber to an ion implantation chamber comprising the steps of:
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a) moving a generally circular wafer from a supply and placing the wafer on a wafer support; b) moving a movable chamber wall to enclose the wafer in an intermediate chamber; c) withdrawing fluid from the intermediate chamber through a first conduit in fluid communication with the intermediate chamber but spaced from the wafer by a diffuser plate attached to the movable chamber wall; d) monitoring pressure within the intermediate chamber and moving the wafer into a process chamber at a reduced pressure when sensed pressure within the intermediate chamber reaches the reduced pressure; e) processing the generally circular wafer; f) moving the wafer from the process chamber into the intermediate chamber; and g) increasing the pressure in the intermediate chamber by infusing fluid into the intermediate chamber through a second conduit concentric with the first conduit before removing the generally circular wafer from the intermediate chamber. - View Dependent Claims (16)
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17. An ion implantation system for sequentially treating workpieces comprising:
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a) an implantation chamber that defines a chamber interior into which the workpieces are moved for treatment, said chamber having a workpiece opening for inserting workpieces into the chamber prior to treatment and removing the workpieces from the chamber after they have been treated; b) a pressure chamber in fluid communication with the implantation chamber through the opening of the implantation chamber including a workpiece support positioned within the pressure chamber at a region bounded by a wall having a first fluid opening for allowing a fluid to enter the pressure chamber through an inlet flow control passageway and a second fluid opening concentric with the first opening for evacuating the pressure chamber by withdrawing fluid in the pressure chamber through an outlet flow control passageway; c) a flow diffuser mounted to a wall of the pressure chamber between the workpiece support and the first and second fluid openings that defines a radial fluid flow path to a center region of the workpiece support; and d) a flow controller for controlling fluid flow entering or exiting the pressure chamber via the first and second flow control passageways to enable workpieces to be moved into and out of the pressure chamber at atmospheric pressure and moved into and removed from the implantation chamber at a pressure less than atmospheric pressure;
said controller including means for performing a cleaning cycle to cleanse contaminants from said pressure chamber by simultaneously routing pressurized fluid into the pressure chamber through the inlet flow control passageway and out the outlet flow control passageway. - View Dependent Claims (18)
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Specification