Method of forming contact hole arrays using a hybrid spacer technique
AssigneeSanDisk 3D LLC
InventorsChun-Ming Wang, Chenche Huang, Masaaki Higashitani
Life of this patent
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Abstract
One embodiment of the invention provides a method of forming a plurality of contact holes, including forming a first feature and a second feature over an underlying material, forming sidewall spacers on the first and second features, removing the first and second features without removing the sidewall spacers, forming a cover mask at least partially exposing the sidewall spacers, and etching the underlying material using the cover mask and the sidewall spacers as a mask to form the plurality of contact holes.
Claims17
A method of forming a plurality of contact holes, comprising:
- forming a first feature and a second feature over an underlying material;
- forming sidewall spacers on the first and second features;
- removing the first and second features without removing the sidewall spacers;
- forming a cover mask at least partially exposing the sidewall spacers;
- and
- etching the underlying material using the cover mask and the sidewall spacers as a mask to form the plurality of contact holes,
- wherein the cover mask comprises at least one strip extending over the sidewall spacers such that at least two rows of non-staggered contact holes are formed, wherein the contact holes comprise 19 nm or smaller resolution.
A method of forming a plurality of contact holes, comprising:
- forming at least one underlying layer over a substrate;
- forming a plurality of spaced apart features over the at least one underlying layer;
- forming a spacer layer over the features and the at least one underlying layer;
- etching the spacer layer to form a spacer pattern comprising a plurality of spacer shells, wherein each one of the spacer shells is formed so as to completely surround sidewalls of a respective one of the features while exposing an upper surface of each feature and portions of the underlying layer located between adjacent spacer shells;
- removing the features without removing the spacer shells to expose top portions of the underlying layer below locations previously occupied by the features;
- forming a cover mask comprising at least a first strip portion and a second strip portion of cover mask material formed spaced apart and substantially parallel to one another such that the first strip portion covers a first wall and the second strip portion covers an opposing second wall of each of the spacer shells;
- and
- etching exposed portions of the underlying layer below locations previously occupied by the features and at locations between each of the plurality of spacer shells to form the plurality of contact holes;
- wherein the cover mask further comprises:
- a third strip portion of cover mask material formed above the underlying layer thereby connecting a first end of the first strip portion and a first end of the second strip portion;
- a fourth strip portion of cover mask material formed above the underlying layer thereby connecting a second end of the first strip portion and a second end of the second strip portion;
- and
- at least one additional fifth strip portion of cover mask material formed substantially parallel to and between the first and second strip portions and over the spacer shells;
- wherein:
- the third and fourth strip portions are each substantially perpendicular to the first and second strip portions, and the spacer shells are located between the third and fourth strip portions;
- a first end of the at least one additional fifth strip portion contacts the third strip portion, and a second end of the at least one additional fifth strip portion contacts the fourth strip portion;
- and
- the contact holes have a substantially square cross-sectional shape.
Dependencies are inferred from the claim text.