Cross-Linkable Protective Layer for Sub-10 nm Gap Filling
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Solution Overview
Problem
As semiconductor devices miniaturize, the gap-filling ability and wet etch resistance of bottom layers in etching masks become compromised, leading to potential damage of work function metal layers during photolithographic processing, especially in features with gaps less than 10 nm.
Innovation Solution
A composition of cross-linkable polymers with specific molecular weights and functional groups is used to form a protective layer that enhances gap-filling ability, wet etch resistance, and adhesion to metal layers, including a polymer backbone and end units with cross-linkable groups, which are cross-linked to form a robust protective layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional photolithographic materials and processes are used, then manufacturing process is simple, but gap-filling ability deteriorates and wet etch resistance is compromised in features with gaps less than 10 nm
Solution Approach 1:
The patent uses a bi-layer mask structure combining a bottom layer (BARC) and a top layer (photoresist), where each layer has specific functional properties. The bottom layer is designed with high gap-filling ability to fill sub-10nm gaps, while the top layer provides patterning capability. This composite structure resolves the contradiction by distributing functions across multiple materials rather than relying on a single material to perform all functions.
Solution Approach 2:
The etching mask is segmented into multiple functional layers: a bottom layer for gap-filling and a top layer for photolithographic patterning. This segmentation allows each layer to be optimized independently for its specific function, enabling the bottom layer to achieve high gap-filling ability in sub-10nm features without compromising the overall process simplicity.
2Manufacturing precision
If bottom layer thickness is increased to improve gap-filling ability, then gap-filling improves, but adhesion to metal layers deteriorates
Solution Approach 1:
The bottom layer is engineered with specific local properties including controlled thickness (5-20 nm), specific molecular weight (1000-10000 daltons), and functional groups (hydroxyl, carboxyl, or amine groups) that enhance both gap-filling ability and adhesion to metal layers. This localized optimization of material properties resolves the contradiction by achieving high gap-filling in sub-10nm features while maintaining strong adhesion through chemical functionality.
Solution Approach 2:
The patent optimizes specific parameters of the bottom layer including thickness (5-20 nm), molecular weight (1000-10000 daltons), and chemical composition (polymers with hydroxyl, carboxyl, or amine groups). These parameter changes enable the bottom layer to simultaneously achieve high gap-filling ability in sub-10nm features and strong adhesion to underlying metal layers, resolving the contradiction between these two properties.
3Length of moving object
If photolithographic process window is narrowed due to device miniaturization, then device size decreases, but process robustness deteriorates
Solution Approach 1:
The bottom layer is applied and cured before the photolithographic patterning step, creating a robust foundation that fills sub-10nm gaps and provides a stable platform for subsequent processing. This preliminary action ensures that the photolithographic process window remains adequate even as device dimensions are reduced, maintaining process robustness while enabling device miniaturization.
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
The protective layer effectively fills gaps and withstands wet etching processes, ensuring the integrity of work function metal layers and improving the electrical performance of semiconductor devices.
Implementation Method 1
A composition of cross-linkable polymers with specific molecular weights and functional groups is used to form a protective layer that enhances gap-filling ability, wet etch resistance, and adhesion to metal layers, including a polymer backbone and end units with cross-linkable groups, which are cross-linked to form a robust protective layer.
Implementation Method 2
The protective layer effectively fills gaps and withstands wet etching processes, ensuring the integrity of work function metal layers
Data Source
AI summary
A method of manufacturing a semiconductor device includes the following operations. A protective layer is formed over a substrate, in which the protective layer is formed by a composition including a polymer having a polymer backbone and end groups. The polymer backbone is formed by polymerizing a monomer composition including first monomers, and each of the first monomer independently has an aryl substituted with 1, 2, 3, 4, or 5 hydroxyl groups. The end groups include:or combinations thereof. A is a substituted or unsubstituted hydrocarbon group. B is a hydroxyl group, an alkyl group, or a fluoroalkyl group. A photoresist layer is formed over the protective layer. The photoresist layer is patterned.