Serpentine Conductive Socket Layout for Uniform Etch Rates
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Solution Overview
Problem
The challenge of reliably landing contacts and/or vias on conductive lines with small widths and small pitches without electrically shorting neighboring lines, due to the small dimensions and pitches, is exacerbated by uneven etch and removal rates at conductive sockets with large, rectangular top layouts.
Innovation Solution
The formation of conductive sockets with a serpentine layout and width similar to the conductive lines, using a sidewall spacer structure as a mask for both conductive lines and sockets, allows for uniform etch and removal rates, reducing the need for separate photomasks or reticles and minimizing over or under removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conductive sockets with large rectangular top layouts are used, then contact landing area is improved, but etch and removal rates become uneven causing manufacturing defects
Solution Approach 1:
The patent applies serpentine curvature to the conductive socket layout instead of rectangular geometry. The serpentine path with controlled width creates uniform etch exposure along the entire socket length, eliminating the uneven etch rates that occur with large rectangular layouts while maintaining adequate contact landing area.
Solution Approach 2:
The patent changes the geometric parameters of the conductive socket from large rectangular dimensions to a serpentine configuration with width matching the conductive line width. This parameter change ensures uniform etch and removal rates while providing sufficient area for contact landing through the extended serpentine path.
2Manufacturing precision
If separate photomasks or reticles are used for conductive lines and sockets, then manufacturing precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent merges the patterning of conductive lines and conductive sockets into a single photomask or reticle. The serpentine socket layout is designed to be formed simultaneously with the conductive lines through one exposure step, eliminating the need for separate photomasks while maintaining manufacturing precision through the unified design approach.
Solution Approach 2:
The single photomask serves multiple functions by defining both the conductive line patterns and the serpentine conductive socket patterns in one exposure. This universal mask design reduces device complexity and cost while maintaining the precision needed for small width and small pitch features.
3Productivity
If photolithography is used to transfer patterns, then manufacturing efficiency is improved, but feature size limits are reached
Solution Approach 1:
The patent segments the conductive socket into a serpentine configuration that follows the path of the conductive line. This segmentation allows the socket to be formed using the same photolithography step as the line, maintaining manufacturing efficiency while enabling smaller feature sizes through self-aligned patterning.
Solution Approach 2:
The serpentine conductive socket layout is designed in advance to match the conductive line geometry, allowing both features to be formed in a single photolithography exposure. This preliminary design enables the use of standard photolithography tools to achieve smaller feature sizes without requiring additional processing steps.
Data Source
AI summary
Various embodiments of the present disclosure are directed towards methods for forming conductive lines and conductive sockets using mandrels with turns, as well as the resulting conductive lines and sockets. A conductive socket of the present disclosure may have a top layout with at least one turn and with a width that is substantially the same as that of conductive lines along the at least one turn. Such a top layout may reduce loading during formation of the conductive socket. Conductive lines of the present disclosure may comprise outer conductive lines and inner conductive lines having ends laterally offset from ends of the outer conductive lines along lengths of the conductive lines. Formation of the inner and outer conductive lines using a mandrel with a turn may enlarge a process window while cutting ends of a sidewall spacer structure from which the inner and outer conductive lines are formed.