Contact plug and interconnect employing a barrier lining and a backfilled conductor material
DCFirst Claim
1. A low resistance contact plug, stable in the presence of aluminum, formed in a contact hole less than about μ
- m2 in area through at least one insulating layer formed on a semiconductor surface to at least a portion of a doped region in said semiconductor surface, said contact comprising;
(a) an adhesion and contacting layer of titaniun about 100-800Å
thick formed at least along the walls of said contact hole through said at least one insulating layer and in contact with said portion of said doped region;
(b) a barrier layer formed over said adhesion and contacting layer; and
(c) a conductive material formed over said barrier layer and at least substantially filling said contact hole; and
a patterned interconnect electrically and physically contacting said plug.
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Abstract
A stable, low resistance contact is formed in a contact hole (16) through an insulating layer (14), e.g., silicon dioxide, formed on a surface of a semiconductor substrate (12), e.g., silicon, to a portion of a doped region (10) in said semiconductor surface. The contact comprises (a) an adhesion and contacting layer (18) of titanium formed along the walls of the insulating layer and in contact with the portion of the doped region; (b) a barrier layer (20) formed over the adhesion and contacting layer; and (c) a conductive material (22) formed over the barrier layer and at least substantially filling said contact hole. A patterned metal layer (26) forms an ohmic contact interconnect to other devices and external circuitry. The adhesion and contacting layer and barrier layer are either physically or chemically vapor deposited onto the oxide surface. The conductive layer comprises one of CVD or bias sputtered tungsten, molybdenum or in situ doped CVD polysilicon. The contact of the invention avoids the problems of encroachment at the oxide-silicon interface and worm holes associated with other contact schemes but retains process simplicity.
258 Citations
18 Claims
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1. A low resistance contact plug, stable in the presence of aluminum, formed in a contact hole less than about μ
- m2 in area through at least one insulating layer formed on a semiconductor surface to at least a portion of a doped region in said semiconductor surface, said contact comprising;
(a) an adhesion and contacting layer of titaniun about 100-800Å
thick formed at least along the walls of said contact hole through said at least one insulating layer and in contact with said portion of said doped region;(b) a barrier layer formed over said adhesion and contacting layer; and (c) a conductive material formed over said barrier layer and at least substantially filling said contact hole; and a patterned interconnect electrically and physically contacting said plug. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
- m2 in area through at least one insulating layer formed on a semiconductor surface to at least a portion of a doped region in said semiconductor surface, said contact comprising;
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10. A low resistance contact plug, stable in the presence of aluminum, formed in a contact hole less than about 2 μ
- m2 in area through at least one insulating layer formed on a semiconductor surface to at least a portion of a doped region in said semiconductor surface, said contact comprising;
(a) an adhesion and contacting layer of titanium about 100-800 Å
thick formed at least along the walls of said contact hole through said at least one insulating layer and in contact with said portion of said doped region;(b) a barrier layer comprising a material selected from the group consisting of titanium nitride, titanium-tungsten, titanium tungsten nitride, and boron nitride formed over said adhesion and contacting layer; and (c) a conductive material formed over said barrier layer and at least substantially filling said contact hole; and a patterned interconnect electrically and physically contacting said plug. - View Dependent Claims (11, 12, 13, 14)
- m2 in area through at least one insulating layer formed on a semiconductor surface to at least a portion of a doped region in said semiconductor surface, said contact comprising;
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15. A low resistance contact plug, stable in the presence of aluminum, formed in a contact hole less than about 2 μ
- m2 in area through a layer of silicon dioxide formed on a silicon surface to at least a portion of a doped region in said silicon surface, said contact comprising;
(a) an adhesion and contacting layer of sputtered titanium about 100-800 Å
thick formed at least along the walls of said contact hole through said silicon dioxide and in contact with said portion of said doped region;(b) a barrier layer of sputtered titanium nitride formed over said adhesion and contacting layer; and (c) a CVD conductive material selected from the group consisting of tungsten and in situ doped polysilicon formed over said barrier layer and at least substantially filling said contact hole; and
a patterned interconnect electrically and physically contacting said plug. - View Dependent Claims (16, 17, 18)
- m2 in area through a layer of silicon dioxide formed on a silicon surface to at least a portion of a doped region in said silicon surface, said contact comprising;
Specification