High aspect ratio contacts

Abstract

A contact formed in accordance with a process for etching a insulating material to produce an opening having an aspect ratio of at least 15:1 by first exposing the insulating material to a second plasma of a second gaseous etchant comprising Ar, Xe, and combinations thereof to form an opening having an aspect ratio of less than 15:1. Secondly, the insulating material is exposed to a first plasma of a first gaseous etchant having at least fifty percent helium (He) to etch the opening having an aspect ratio of at least 15:1, thereby increasing the aspect ratio to greater than 15:1, where the first gaseous etchant has a lower molecular weight than the second gaseous etchant.

1 . A capacitor comprising:
 a first conducting material for a bottom electrode formed in an opening having a bottom and a side in a insulating material that allows an axis perpendicular to the insulating material to pass through the opening to the bottom uninterrupted by the side of the opening, where the opening defines an essentially elongate symmetrical shape having an aspect ratio of at least 20:1;   a dielectric material formed over the first conducting material; and   a second conducting material for a top electrode formed over the dielectric material.   
     
     
         2 . The capacitor of  claim 1 , wherein the opening is formed by exchanging a first ion gaseous etchant for a second ion gaseous etchant, the second ion gaseous etchant including a second inert gas and a second reactive gas, once the aspect ratio of the opening is etched to approximately 15:1, the second ion gaseous etchant being used to further etch the opening to the aspect ratio of at least 20:1, the first ion gaseous etchant includes a first inert gas and the first reactive gas. 
     
     
         3 . The capacitor of  claim 2 , wherein the second ion gaseous etchant has a lower mean molecular weight of the mixture of the second inert gas and the second reactive gas than the mean molecular weight of the mean molecular weight of the mixture of the first inert gas and the first reactive gas. 
     
     
         4 . The capacitor of  claim 3 , wherein the opening is formed by exposing the insulating material in a plasma etch reactor to a plasma of the first ion gaseous etchant including the first inert gas and a first reactive gas, to etch the opening to an aspect ratio of approximately 15:1. 
     
     
         5 . The capacitor of  claim 1 , wherein the opening is formed by:
 first exposing the insulating material to a plasma of a second gaseous etchant comprising Ar, Xe, and combinations thereof to etch an opening to a first aspect ratio of less than 15:1;   exposing the insulating material to a plasma of a first gaseous etchant having at least fifty percent helium (He) to etch the opening from the first aspect ratio to a second aspect ratio of at least 15:1 with the plasma of the first gaseous etchant; and   exposing the insulating material to a plasma of a reactive gaseous etchant in conjunction with each of the first and second gaseous etchants,   wherein the first gaseous etchant has a lower molecular weight than the second gaseous etchant.   
     
     
         6 . The capacitor of  claim 5 , wherein the second gaseous etchant includes He. 
     
     
         7 . The capacitor of  claim 6 , formed in accordance with the process for etching the insulating material further comprising exchanging the second gaseous etchant for the first gaseous etchant once the aspect ratio of the etched openings reaches approximately 15:1. 
     
     
         8 . The capacitor of  claim 5 , where the first gaseous etchant is a mixture of He and Ar. 
     
     
         9 . The capacitor of  claim 5 , where the first gaseous etchant is approximately ninety percent He and approximately ten percent Ar. 
     
     
         10 . The capacitor of  claim 5 , where the first gaseous etchant is approximately one hundred percent He. 
     
     
         11 . The capacitor of  claim 5 , wherein the contact has an aspect ratio of at least 20:1. 
     
     
         12 . The capacitor of  claim 1 , wherein the opening is formed by:
 first exposing the insulating material to a second plasma of a second gaseous etchant comprising Ar, Xe, and combinations thereof to form an opening having an aspect ratio of less than 15:1; and   second exposing the insulating material to a first plasma of a first gaseous etchant having at least fifty percent helium (He) to etch the opening having an aspect ratio of at least 15:1, thereby increasing the aspect ratio to greater than 15:1,   wherein the first gaseous etchant has a lower molecular weight than the second gaseous etchant.   
     
     
         13 . A memory device comprising:
 a transistor;   a conductive line; and   a capacitor connected by the conductive line to the transistor,   wherein the capacitor is contained in a insulating material having an opening with a bottom and a side in the insulating material that allows an axis perpendicular to the insulating material to pass through the opening to the bottom uninterrupted by the side of the opening and having an aspect ratio of at least 20:1.   
     
     
         14 . The memory device of  claim 13 , wherein the opening is formed by:
 first exposing the insulating material to a second plasma of a second gaseous etchant comprising Ar, Xe, and combinations thereof to form the opening to an aspect ratio of approximately 15:1; and   second exposing the insulating material to a first plasma of a first gaseous etchant having at least fifty percent helium (He) to etch the opening to an aspect ratio of at least 15:1,   wherein the first gaseous etchant has a lower molecular weight than the second gaseous etchant.   
     
     
         15 . The memory device of  claim 13 , wherein the opening is formed by:
 exposing the insulating material in a plasma etch reactor to a plasma of a heavy ion gaseous etchant to etch the opening to an aspect ratio of less than approximately 15:1; and   exchanging the heavy ion gaseous etchant for a light ion gaseous etchant including a second inert gas and a second reactive gas, once the aspect ratio of the etched opening reaches approximately 15:1 to further etch the opening to the aspect ratio of at least 20:1,   wherein the light ion gaseous etchant has a lower mean molecular weight of the mixture of the second inert gas and the second reactive gas than the mean molecular weight of the first inert gas and the first reactive gas in the heavy ion gaseous etchant.   
     
     
         16 . The memory device of  claim 13 , wherein the opening is formed by:
 first exposing the insulating material to a second plasma of a second gaseous etchant to form the opening to an aspect ratio of approximately 15:1; and   second exposing the insulating material to a first plasma of a first gaseous etchant to etch the opening to an aspect ratio of greater than 15:1,   wherein the first gaseous etchant has a lower molecular weight than the second gaseous etchant.   
     
     
         17 . The memory device of  claim 13 , wherein the first plasma of a first gaseous etchant has at least fifty percent helium (He). 
     
     
         18 . The memory device of  claim 14 , wherein the memory device is a memory cell of a memory selected from a group comprising a dynamic random access memory (DRAM) and a static random access memory (SRAM). 
     
     
         19 . A system, comprising:
 a data input device;   a data output device;   a processor coupled to the data input and data output devices; and   a random access memory (RAM) device coupled to the processor, where the memory device includes:
 a transistor; 
 a conductive line connected to the transistor; and 
 a capacitor connected to the conductive line, 
 wherein the capacitor is contained in a insulating material having an opening with a bottom and a side in the insulating material that allows an axis perpendicular to the insulating material to pass through the opening to the bottom uninterrupted by the side of the opening having an aspect ratio of at least 20:1. 
   
     
     
         20 . The memory device of  claim 19 , wherein the opening is formed by:
 first exposing the insulating material to a plasma of a first gaseous etchant to form the opening to an aspect ratio of less than 15:1; and   second exposing the insulating material to a plasma of a second gaseous etchant having a lower molecular weight than the first gaseous etchant and including at least fifty percent helium (He) to increase the aspect ratio to greater than 15:1.