INTERLAYER CONDUCTOR AND METHOD FOR FORMING
First Claim
1. A method for forming a device having contact landing areas at varying depths in a substrate, comprising:
- forming a patterned, first mask layer on the substrate, including a contact area opening on the substrate;
forming a second mask layer over the first mask layer, the second mask layer filling said contact area opening;
using a patterned, third mask layer to define a starting via location within the contact area opening;
etching a via through the second mask layer at the starting via location; and
forming contact landing areas at a plurality of depths in the substrate by iteratively etching an increment in depth into the substrate through the via, and trimming the second mask layer to enlarge the via.
1 Assignment
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Accused Products
Abstract
A 3-D structure includes a stack of active layers at different depths has a plurality of contact landing areas on respective active layers within a contact area opening. A plurality of interlayer conductors, each includes a first portion within a contact area opening extending to a contact landing area, and a second portion in part outside the contact area opening above the top active layer. The first portion has a transverse dimension Y1 that is nominally equal to the transverse dimension of the contact area opening, and the second portion having a transverse dimension Y2 that is greater than the transverse dimension of the contact area opening. The active layers can be bit lines or word lines for a 3-D memory device, or other active layers in integrated circuits.
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Citations
21 Claims
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1. A method for forming a device having contact landing areas at varying depths in a substrate, comprising:
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forming a patterned, first mask layer on the substrate, including a contact area opening on the substrate; forming a second mask layer over the first mask layer, the second mask layer filling said contact area opening; using a patterned, third mask layer to define a starting via location within the contact area opening; etching a via through the second mask layer at the starting via location; and forming contact landing areas at a plurality of depths in the substrate by iteratively etching an increment in depth into the substrate through the via, and trimming the second mask layer to enlarge the via. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for forming a device having contact landing areas at varying depths in a substrate, comprising:
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forming contact landing areas at a plurality of depths in the substrate within a contact area opening in a first insulating layer, wherein the contact area opening has a longitudinal dimension and a transverse dimension; forming an etch stop layer (e.g., silicon nitride) over the contact landing areas on substrate, on sidewalls of the contact area opening, and on the overlying mask layer; forming a second insulating layer over the etch stop layer, the insulating layer filling the contact area opening; defining a plurality of interlayer conductor locations for corresponding contact landing areas in the contact area opening, the interlayer conductor locations having a transverse dimension that is greater than the transverse dimension of the contact area opening, and having a longitudinal dimension; etching through the second insulating layer at the interlayer conductor locations by using a process selective for the second insulating layer over the etch stop layer, and then etching openings in the etch stop layer exposing the contact landing areas at the plurality of depths to form interlayer conductor vias while leaving at least portions of the etch stop layer on the sidewalls; and filling the interlayer conductor vias with a conductive material to form interlayer conductors. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A 3-D structure, comprising:
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a stack including a plurality of active layers at a corresponding plurality of depths in the stack, including a top active layer, and a plurality of contact landing areas on respective active layers; a first insulating layer over the top active layer, and having a contact area opening over the plurality of contact landing areas, the contact area opening having a longitudinal dimension and a transverse dimension; a second insulating layer over the first insulating layer, and filling the contact area opening and having a depth over the first insulating layer; a plurality of interlayer conductors in the second insulating layer, the interlayer connectors having a first portion within the contact area opening through the first insulating layer and extending to a corresponding one of said contact landing areas, and a second portion in part outside the contact area opening above the first insulating layer, said first portion having a transverse dimension Y1 that is nominally equal to the transverse dimension of the contact area opening, and said second portion having a transverse dimension Y2 that is greater than the transverse dimension of the contact area opening. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21)
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Specification