Techniques and apparatus for unidirectional hole elongation using angled ion beams

Abstract

A method of patterning a substrate. The method may include providing a cavity in a layer, disposed on the substrate, the cavity having a first length along a first direction and a first width along a second direction, perpendicular to the first direction, and wherein the layer has a first height along a third direction, perpendicular to the first direction and the second direction. The method may include depositing a sacrificial layer over the cavity in a first deposition procedure; and directing angled ions to the cavity in a first exposure, wherein the cavity is etched, and wherein after the first exposure, the cavity has a second length along the first direction, greater than the first length, and wherein the cavity has a second width along the second direction, no greater than the first width.

What is claimed is: 
     
         1 . An apparatus, comprising;
 at least one plasma chamber, the at least one plasma chamber comprising an extraction plate having an extraction aperture arranged to:
 direct a reactive angled ion beam to a substrate at a non-zero angle of incidence with respect to a normal to a substrate plane; and 
 direct depositing species to the substrate to deposit a polymer layer on the substrate; and 
   a controller, coupled to the at least one plasma chamber, and arranged to cycle the substrate over a plurality of etch cycles, wherein a given etch cycle comprises deposition of the polymer layer from the depositing species and etching of the substrate using the reactive angled ion beam.   
     
     
         2 . The apparatus of  claim 1 , further comprising:
 a process chamber to house the substrate; and   a substrate stage, disposed in the process chamber and arranged to scan the substrate with respect to the reactive angled reactive ion beam along a first direction within the substrate plane.   
     
     
         3 . The apparatus of  claim 2 , the extraction aperture being elongated along a second direction, perpendicular to the first direction. 
     
     
         4 . The apparatus of  claim 1 , wherein the at least one plasma chamber is a single plasma chamber. 
     
     
         5 . The apparatus of  claim 1 , further comprising a beam blocker, disposed over the extraction aperture, wherein the beam blocker defines the first extraction aperture and a second extraction aperture, wherein the reactive angled ion beam is a first reactive angled ion beam, wherein the second extraction aperture is arranged to direct a second reactive angled ion beam to the substrate at a second non-zero angle of incidence with respect to the normal to the substrate plane. 
     
     
         6 . The apparatus of  claim 2 , further comprising a bias supply to apply a voltage between the at least one plasma chamber and the process chamber, wherein a first value of the voltage for generating the reactive angled ion beam is greater than a second value of the voltage for depositing the polymer layer. 
     
     
         7 . The apparatus of  claim 6 , wherein the second value is 200 V or less. 
     
     
         8 . An apparatus, comprising;
 a loadlock to receive a substrate;   a transfer chamber, coupled to the loadlock, and arranged to transfer the substrate under vacuum;   an angled ion beam etch station, coupled to the transfer chamber, to direct a reactive angled ion beam to the substrate at a non-zero angle of incidence with respect to a normal to a substrate plane; a   a polymer deposition chamber, coupled to the transfer chamber, arranged to deposit a polymer layer on the substrate; and   a controller, coupled to the polymer deposition chamber, the transfer chamber and the angled ion beam etch station, to cycle the substrate over a plurality of etch cycles, wherein a given etch cycle comprises deposition of the polymer layer in the polymer deposition chamber, etching of the substrate in the angled ion beam etch station, and transporting the substrate between the polymer deposition chamber and the angled ion beam etch station via the transfer chamber.   
     
     
         9 . The apparatus of  claim 8 , the angled ion beam etch station comprising:
 a plasma chamber for generating a plasma therein;   extraction plate, disposed along a side of the plasma chamber, and including an extraction aperture to direct the angled reactive ion beam to the substrate; and   a substrate stage, disposed to scan the substrate with respect to the angled reactive ion beam along a first direction.   
     
     
         10 . The apparatus of  claim 9 , the extraction aperture being elongated along a second direction, perpendicular to the first direction. 
     
     
         11 . The apparatus of  claim 9 , further comprising a beam blocker, disposed over the extraction aperture, wherein the beam blocker defines the first extraction aperture and a second extraction aperture, wherein the reactive angled ion beam is a first reactive angled ion beam, wherein the second extraction aperture is arranged to direct a second reactive angled ion beam to the substrate at a second non-zero angle of incidence with respect to the normal to the substrate plane. 
     
     
         12 . The apparatus of  claim 9 , the plasma chamber comprising a first plasma chamber to generate a first plasma therein, the polymer deposition chamber comprising a second plasma chamber to generate a second plasma therein. 
     
     
         13 . The apparatus of  claim 12 , the first plasma comprising a CF 4 /O 2  plasma, and the second plasma comprising a CH 3 F plasma. 
     
     
         14 . The apparatus of  claim 12 , further comprising a bias supply to apply a first voltage between the first plasma chamber and the substrate, wherein the second plasma chamber is arranged to be biased with respect to the substrate at a second voltage, less than the first voltage.