Method for manufacturing a planar electrical interconnection utilizing isotropic deposition of conductive material
First Claim
1. A method wherein a first electrically insulating layer having a largely planar upper surface is formed on a substructure, and first openings are etched through the first insulating layer down to the substructure, characterized by the steps of:
- forming a first electrically conductive planarizing layer having a largely planar upper surface on the first insulating layer and in the first openings by an operation in which tungsten or molybdenum is isotropically deposited to create at least a portion of the first planarizing layer extending from its upper surface partway into the first openings;
removing a relatively uniform thickness of the first planarizing layer down to the upper surface of the first insulating layer;
forming a second electrically insulating layer having a largely planar upper surface on the first insulating layer and on the material in the first openings;
etching second openings through the second insulating layer down to the material in the first openings;
forming a second electrically conductive planarizing layer having a largely planar upper surface on the second insulating layer and in the second openings by an operation in which tungsten or molybdenum is isotropically deposited to create at least a portion of the second planarizing layer extending from its upper surface partway into the second openings; and
removing selected material of the second planarizing layer so as to leave the remainder of the second planarizing layer in a desired pattern;
where each isotropic deposition entails providing tungsten or molybdenum from a species in a vapor by a surface-controlled chemical reaction in the immediate vicinity of where the tungsten or molybdenum accumulates.
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Accused Products
Abstract
A planar electrical interconnection system suitable for an integrated circuit is created by a process in which an insulating layer (31) having a planar upper surface is formed on a substructure after which openings (32) are etched through the insulating layer. A conductive planarizing layer (33) having a planar upper surface is formed on the insulating layer and in the openings by an operation involving isotropic deposition of a material, preferably tungsten, to create at least a portion of the planarizing layer extending from its upper surface partway into the openings. The planarizing layer is then etched down to the insulating layer. Consequently, its upper surface is coplanar with that of the material (33'"'"') in the openings. The foregoing steps are repeated to create another coplanar conductive/insulating layer (34 and 36'"'"'). If the lower openings are vias while the upper openings are grooves, the result is a planar interconnect level. Further planar interconnect levels can be formed in the same way.
69 Citations
30 Claims
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1. A method wherein a first electrically insulating layer having a largely planar upper surface is formed on a substructure, and first openings are etched through the first insulating layer down to the substructure, characterized by the steps of:
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forming a first electrically conductive planarizing layer having a largely planar upper surface on the first insulating layer and in the first openings by an operation in which tungsten or molybdenum is isotropically deposited to create at least a portion of the first planarizing layer extending from its upper surface partway into the first openings; removing a relatively uniform thickness of the first planarizing layer down to the upper surface of the first insulating layer; forming a second electrically insulating layer having a largely planar upper surface on the first insulating layer and on the material in the first openings; etching second openings through the second insulating layer down to the material in the first openings; forming a second electrically conductive planarizing layer having a largely planar upper surface on the second insulating layer and in the second openings by an operation in which tungsten or molybdenum is isotropically deposited to create at least a portion of the second planarizing layer extending from its upper surface partway into the second openings; and removing selected material of the second planarizing layer so as to leave the remainder of the second planarizing layer in a desired pattern;
where each isotropic deposition entails providing tungsten or molybdenum from a species in a vapor by a surface-controlled chemical reaction in the immediate vicinity of where the tungsten or molybdenum accumulates. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method in which an electrically insulating layer having a largely planar upper surface is formed on a substructure, and first openings are etched through the first insulating layer down to the substructure, characterized by the steps of:
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forming a first planarizing layer by (1) creating a first lower layer on the first insulating layer and in the first openings, the first lower layer comprising electrically conductive material that adheres to the first insulating layer, adheres to the material exposed through the first openings, and acts as a nucleation surface for tungsten, and (2) isotropically depositing a sufficient amount of tungsten on the first lower layer to form a much thicker first upper layer having a largely planar upper surface; removing a relatively uniform thickness of the first planarizing layer down to the upper surface of the first insulating layer; forming a second electrically insulating layer having a largely planar upper surface on the first insulating layer and on the material in the first openings; etching second openings through the second insulating layer down to the material in the first openings; forming a second planarizing layer by (1) creating a second lower layer on the second insulating layer and in the second openings, the second lower layer comprising electrically conductive material that adheres to the second insulating layer, adheres to the material exposed through the second openings, and acts as a nucleation surface for tungsten, and (2) isotropically depositing a sufficient amount of tungsten on the second lower layer to form a much thicker second upper layer having a largely planar upper surface; and removing a relatively uniform thickness of the second planarizing layer down to the upper surface of the second insulating layer. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method in which an electrically insulating layer having a largely planar upper surface is formed on a substructure, and first openings are etched through the first insulating layer down to the substructure, each first opening being a via whose length and width are approximately the same, characterized by the steps of:
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forming a substantially void-free first planarizing layer by (1) creating a first lower layer on the first insulating layer and in the first openings, the first lower layer consisting substantially of electrically conductive material that adheres to the first insulating layer, adheres to the material exposed through the first openings, and acts as a tungsten nucleation surface, and (2) isotropically depositing tungsten on the first lower layer to form a much thicker first upper layer having a largely planar upper surface; removing a relatively uniform thickness of the first planarizing layer down to the upper surface of the first insulating layer; forming a second electrically insulating layer having a largely planar upper surface on the first insulating layer and on the material in the first openings; etching second openings through the second insulating layer down to the material in the first openings, each second opening being a groove having much greater length than width; forming a substantially void-free second planarizing layer by (1) creating a second lower layer on the second insulating layer and in the second openings, the second lower layer consisting substantially of electrically conductive material that adheres to the second insulating layer, adheres to the material exposed through the second openings, and acts as a tungsten nucleation surface, and (2) isotropically depositing tungsten on the second lower layer to form a much thicker second upper layer having a largely planar upper surface; and removing a relatively uniform thickness of the second planarizing layer down to the upper surface of the second insulating layer;
where each isotropic deposition entails providing tungsten from a species in a vapor by a surface-controlled chemical reaction in the immediate vicinity of where the tungsten accumulates. - View Dependent Claims (23, 24)
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25. A method wherein an electrically insulating layer having a largely planar upper surface is formed on a substructure, and openings are etched through the insulating layer down to the substructure, characterized by the steps of:
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forming a continuous electrically conductive layer by (1) creating a lower layer over the insulating layer and in the openings, the lower layer consisting substantially of electrically conductive material that adheres to the insulating layer, adheres to the material exposed through the openings, and acts as a tungsten nucleation surface, and (2) creating a much thicker upper layer of tungsten over the lower layer by an operation in which tungsten is isotropically deposited from a species in a vapor by a surface-controlled chemical reaction in the immediate vicinity of where the tungsten accumulates, material of the continuous layer filling the openings in a substantially void-free manner; and removing material of the continuous layer down to the upper surface of the insulating layer. - View Dependent Claims (26, 27, 28, 29, 30)
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Specification