Selective ion filtering in a multipurpose chamber

Abstract

A multipurpose semiconductor process chamber includes a vessel wall that encloses contiguous first and second volumes of the multipurpose chamber, and means for selectively effectively preventing ions moving across a plane that partitions the first volume from the second volume. For example, the means can include an electromagnet, or at least one permanent magnet, that is operable to impose and remove a magnetic field with field lines extending in the plane.

What is claimed is: 
     
         1 . An apparatus comprising:
 a vessel wall that encloses contiguous first and second volumes of a multipurpose chamber;   a first vacuum-sealable opening in the vessel wall for introducing a semiconductor wafer into the first volume of the multipurpose chamber;   a second vacuum-sealable opening and an electrode for producing a plasma in the second volume of the multipurpose chamber; and   a selective ion filter that is operable between an activated condition in which the selective ion filter effectively prevents ions passing across a plane that partitions the first volume from the second volume, and a de-activated condition in which the selective ion filter permits ions to pass between the first and second volumes.   
     
     
         2 . The apparatus of  claim 1  wherein the selective ion filter comprises an electromagnet and control circuitry connected to energize the electromagnet to impose a magnetic field with field lines that extend along the plane that partitions the first volume from the second volume. 
     
     
         3 . The apparatus of  claim 2  wherein the control circuitry is configured to energize the electromagnet in response to the first vacuum-sealable opening being sealed. 
     
     
         4 . The apparatus of  claim 3  wherein the control circuitry is configured to produce a first plasma in the second volume by opening the second vacuum-sealable opening and energizing an electrode, in response to a period of time elapsing after energizing the electromagnet. 
     
     
         5 . The apparatus of  claim 1  wherein the selective ion filter comprises first and second permanent magnets movably mounted to the chamber and movable into and out of an activated condition in which opposed poles of the first and second permanent magnets face each other in a plane extending across the multipurpose chamber between the first and second volumes of the multipurpose chamber, such that the first and second permanent magnets impose a magnetic field with field lines that extend along the plane that partitions the first volume from the second volume. 
     
     
         6 . The apparatus of  claim 5  wherein the first and second permanent magnets are movable between the activated condition and a de-activated condition in which at least one of the first and second permanent magnets is moved away from the plane that partitions the first and second volumes along an axis perpendicular to the plane. 
     
     
         7 . An apparatus comprising:
 a vessel wall that encloses contiguous first and second volumes of a multipurpose chamber; and   means for selectively effectively preventing ions moving across a plane that partitions the first volume from the second volume.   
     
     
         8 . The apparatus of  claim 7  wherein the means for selectively effectively preventing ions moving across the plane comprises means for imposing and removing a magnetic field with field lines that extend along the plane. 
     
     
         9 . The apparatus of  claim 8  wherein the means for imposing and removing the magnetic field include an electromagnet disposed such that, when energized, the electromagnet produces the magnetic field. 
     
     
         10 . The apparatus of  claim 8  wherein the means for imposing and removing the magnetic field include at least one permanent magnet movably mounted such that, in a first position, the at least one permanent magnet produces the magnetic field in the plane, and in a second position the at least one permanent magnet does not produce the magnetic field in the plane.