Directional Patterning of Metal Features With Low Line Width Roughness
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current lithography processes face challenges in achieving smaller feature sizes required for advanced technology nodes due to limitations in resolution and line width roughness, necessitating additional process steps to compensate for these inadequacies.
Innovation Solution
A directional patterning method involving a cyclic deposition and etching process is employed, where a protection layer is deposited and then etched to increase the length of opening patterns in a controlled manner, reducing line width roughness and enabling precise definition of metal features without breaking or bridging, particularly useful for forming metal layers in integrated circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional lithography processes are used to form smaller features, then feature size reduction is attempted, but line width roughness increases and resolution is insufficient
Solution Approach 1:
The patterning process is divided into multiple sequential steps: initial mandrel formation, spacer deposition, and iterative etching/deposition cycles. Each step refines the pattern independently, allowing precise control of line width and reduced roughness accumulation that would occur in a single lithography step.
Solution Approach 2:
Mandrels are formed first as preliminary structures that define the initial pattern. Spacers are then deposited on these mandrels before the mandrels are removed. This preliminary action establishes a template that guides subsequent pattern formation, enabling better precision than direct lithography alone.
2Manufacturing precision
If additional process steps are added to compensate for lithography inadequacies, then manufacturing precision improves, but process complexity increases
Solution Approach 1:
Multiple functions are merged into the spacer deposition and etching process. The spacers serve as both the pattern definition structure and the final metal feature template. The iterative etching and deposition cycles combine pattern refinement with material removal, achieving high precision without requiring separate lithography correction steps.
Solution Approach 2:
The spacer structures self-align to the mandrels through conformal deposition, automatically defining the pattern pitch and dimensions. The etching process selectively removes mandrels while preserving spacers based on material differences, with no additional alignment steps required. This self-service mechanism reduces process complexity despite multiple steps.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method effectively reduces line width roughness to about 2.8 or less, allowing for the precise definition of metal features with narrow pitch without pattern defects, thereby addressing the limitations of existing lithography processes in achieving smaller feature sizes.
Implementation Method 1
a protection layer is deposited conformally on the mask layer
Implementation Method 2
a protection layer is deposited conformally on the mask layer
Implementation Method 3
A first gas is introduced into an etching chamber and a polymer layer is formed on a sidewall and a bottom of the at least one opening pattern
Implementation Method 4
A second gas is introduced into the etching chamber, and therefore, the polymer layer is etched away
Data Source
AI summary
A directional patterning method includes following steps. A substrate is provided with a mask layer thereon, and the mask layer has at least one opening pattern therein. A cyclic deposition and etching process is performed to increase a length of the at least one opening pattern.