Self-Aligned Via Formation Using Directed Self-Assembly
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Solution Overview
Problem
Current lithographic tools struggle to create patterns with critical dimensions small enough to meet design specifications in semiconductor device manufacturing, leading to challenges in via overlay and potential circuit shorts due to resolution limitations.
Innovation Solution
The use of directed self-assembly (DSA) of block copolymers, which micro-phase separate to form nanometer-sized structures, allowing for the creation of fully self-aligned vias that align with metal runners, enhancing via overlay and reducing overlay errors by leveraging the orthogonal nature of metal levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If lithographic tools are used to create patterns, then manufacturing process is simple, but manufacturing precision deteriorates due to resolution limitations
Solution Approach 1:
The block copolymer system performs self-alignment automatically through microphase separation, where the polymer blocks spontaneously organize into domains that align with the underlying metal runners without requiring complex lithographic alignment procedures. The system uses its own internal structure (orthogonal metal levels) to guide the formation of accurately positioned vias.
Solution Approach 2:
The patent changes the physical and chemical parameters of the patterning system by using block copolymers with specific molecular weights, compositions, and phase separation characteristics. These parameter changes enable the formation of nanometer-scale patterns that meet design specifications while simplifying the overall patterning process.
2Manufacturing precision
If lithographic tools are used to create patterns, then process complexity is low, but manufacturing precision deteriorates due to resolution limitations
Solution Approach 1:
The block copolymer system performs self-alignment automatically through microphase separation, where the polymer blocks spontaneously organize into domains that align with the underlying metal runners without requiring complex lithographic alignment procedures. The system uses its own internal structure (orthogonal metal levels) to guide the formation of accurately positioned vias.
Solution Approach 2:
The patent changes the physical and chemical parameters of the patterning system by using block copolymers with specific molecular weights, compositions, and phase separation characteristics. These parameter changes enable the formation of nanometer-scale patterns that meet design specifications while simplifying the overall patterning process.
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
DSA processing increases the overlay budget for via placement, ensuring precise alignment and reducing the risk of shorts in semiconductor circuits by forming self-aligned vias that meet design specifications, thereby improving the accuracy and reliability of semiconductor device manufacturing.
Implementation Method 1
Directed self-assembly (DSA) of block copolymers, which micro-phase separate to form nanometer-sized structures
Implementation Method 2
block copolymers, which micro-phase separate to form nanometer-sized structures
Data Source
AI summary
A formed back-end-of-line (BEOL) metal line layer may include a plurality of metal lines with dielectric oxide caps that are disposed in between each metal lines. To overlay an interconnecting layer of metal lines on a selected metal line of the BEOL metal line layer, a block copolymer (BCP) may be formed on a patterning layer. Thereafter, a selective etching of the formed BCP creates a recess above the selected metal line. The created recess facilitates the overlaying of the interconnecting layer of metal lines.