Contact Window Formation Using Amorphous Carbon Mandrel
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Solution Overview
Problem
Conventional methods for forming contact windows in non-volatile memory devices result in under-cut or side-etch/bowing profiles, leading to increased resistance and potential short circuits between select gates and bit-line contact windows due to reduced size and increased component density.
Innovation Solution
A method involving the formation of a patterned amorphous carbon layer or spin-on coating layer on a substrate, followed by the deposition of an interlayer dielectric layer and a conductive material to create a contact window with a major axis direction almost perpendicular to the substrate surface, eliminating under-cut or side-etch/bowing profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional methods are used to form contact window openings with reduced size and increased component density, then storage capacity increases, but under-cut or side-etch/bowing profiles occur causing seams and increased resistance
Solution Approach 1:
A mandrel layer is formed at the bottom of the contact window opening before filling with conductive material. This preliminary structure prevents under-cut and side-etch/bowing profiles during the filling process, ensuring a perpendicular contact window axis even as component density increases and openings become smaller.
2Quantity of substance
If contact window size is reduced to increase memory cell density, then storage capacity increases, but short circuits between select gates or bit-line contact windows occur
Solution Approach 1:
The mandrel layer is formed in advance at the bottom of contact window openings before conductive material filling. This preliminary structure maintains proper spacing and perpendicular orientation of contact windows, preventing short circuits between adjacent select gates or bit-line contact windows even when component density is increased and contact windows are reduced in size.
3Ease of manufacture
If conventional etching methods are used for contact window formation, then manufacturing simplicity is maintained, but seams form in contact window openings leading to increased resistance
Solution Approach 1:
A mandrel layer is formed at the bottom of contact window openings before filling with conductive material. This preliminary structure prevents seam formation during the filling process by providing a foundation that ensures complete and uniform filling, thereby maintaining low resistance while preserving manufacturing simplicity.
Data Source
AI summary
A method for forming a contact window includes: a step of providing a substrate; a step of forming a patterned amorphous carbon layer or spin-on coating layer, in which a surface of the substrate is exposed at two sides of the amorphous carbon layer or spin-on coating layer; a step of forming an interlayer dielectric layer on the substrate; a step of removing a portion of the interlayer dielectric layer until the patterned amorphous carbon layer or spin-on coating layer is exposed; a step of removing the patterned amorphous carbon layer or spin-on coating layer to form an opening; and a step of filling the opening with a conductive material to form the contact window.