Method for making multilayer connection structure
First Claim
1. A method, for use with a three-dimensional stacked IC device having a stack of at least 4 contact levels at an interconnect region, for creating interconnect contact regions aligned with and exposing landing areas at the contact levels, each contact level comprising a conductive layer and an insulation layer, the method comprising:
- removing at least a portion of any upper layer overlying the interconnect region to expose a first contact level and create contact openings for each contact level;
selecting a set of N etch masks for creating a plurality of levels of interconnect contact regions at the stack of the contact levels, N being an integer equal to at least 2;
using the N masks to etch the contact openings up to and including 2N contact levels, the N masks using step comprising;
using a first mask to etch one contact level for effectively half of the contact openings;
using a second mask to etch two contact levels for effectively half of the contact openings; and
the removing, selecting and using steps being carried out so that the contact openings extend to the 2N contact levels; and
whereby electrical conductors can be formed through the contact openings to contact the landing areas at the contact levels.
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Accused Products
Abstract
A method provides electrical connections to a stack of contact levels of an interconnect region for a 3-D stacked IC device. Each contact level comprises conductive and insulation layers. A portion of any upper layer is removed to expose a first contact level and create contact openings for each contact level. A set of N masks is used to etch the contact openings up to and including 2N contact levels. Each mask is used to etch effectively half of the contact openings. When N is 3, a first mask etches one contact level, a second mask etches two contact levels, and a third mask etches four contact levels. A dielectric layer may be formed on the sidewalls of the contact openings. Electrical conductors may be formed through the contact openings with the dielectric layers electrically insulating the electrical conductors from the sidewalls.
68 Citations
16 Claims
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1. A method, for use with a three-dimensional stacked IC device having a stack of at least 4 contact levels at an interconnect region, for creating interconnect contact regions aligned with and exposing landing areas at the contact levels, each contact level comprising a conductive layer and an insulation layer, the method comprising:
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removing at least a portion of any upper layer overlying the interconnect region to expose a first contact level and create contact openings for each contact level; selecting a set of N etch masks for creating a plurality of levels of interconnect contact regions at the stack of the contact levels, N being an integer equal to at least 2; using the N masks to etch the contact openings up to and including 2N contact levels, the N masks using step comprising; using a first mask to etch one contact level for effectively half of the contact openings; using a second mask to etch two contact levels for effectively half of the contact openings; and the removing, selecting and using steps being carried out so that the contact openings extend to the 2N contact levels; and whereby electrical conductors can be formed through the contact openings to contact the landing areas at the contact levels. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for providing electrical connections to landing areas at a stack of contact levels of an interconnect region for a three-dimensional stacked IC device of a type comprising an interconnect region, the interconnect region including an upper layer with a stack of contact levels beneath the upper layer, each contact level comprising a conductive layer and an insulation layer, the method comprising:
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removing at least a portion of any upper layer overlying the interconnect region to expose a first contact level and create contact openings for each contact level; selecting a set of N etch masks for creating a plurality of levels of interconnect contact regions at the stack of the contact levels, N being an integer equal to at least 2; using the N masks to etch the contact openings up to and including 2N contact levels, the N masks using step comprising; using a first mask to etch one contact level for effectively half of the contact openings; using a second mask to etch two contact levels for effectively half of the contact openings; and the removing selecting and using steps being carried out so that the contact openings define sidewalls and extend to the 2N contact levels; forming a dielectric layer on the sidewalls; and forming electrical conductors through the contact openings to the landing areas at the contact levels, the dielectric layers electrically insulating the electrical conductors from the sidewalls. - View Dependent Claims (13, 14, 15, 16)
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Specification