CMP Gap-Fill Dielectric Hardening for Deep Trench Scratch Reduction
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Solution Overview
Problem
The increasing aspect ratio of deep trenches in FinFET formation during semiconductor manufacturing makes it difficult to fill with dense gap-fill materials, leading to scratch defects during chemical mechanical planarization (CMP) and poor adhesion between layers, which can cause leakage, shorts, and other issues in IC products.
Innovation Solution
Treating the lower density gap-fill material with a thermally controlled aqueous oxidizer to enhance its hardness and adhesion with a higher density material before CMP, reducing scratch defects and improving layer adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If low density gap-fill material is used to fill deep trenches with high aspect ratio, then the trenches can be properly filled, but scratch defects occur during CMP processes
Solution Approach 1:
The patent applies thermal treatment to change the physical and chemical parameters of the gap-fill material. By heating the material to specific temperatures (e.g., 400-800°C), the material undergoes densification and cross-linking, transforming its properties to resist CMP scratching while maintaining the ability to fill high aspect ratio trenches
Solution Approach 2:
The patent creates a composite structure by depositing multiple layers of gap-fill materials with different densities. A first low-density layer fills the deep trenches, while a second high-density layer is deposited on top to provide scratch resistance during CMP, combining the advantages of both material types
2Reliability
If two or more layers of gap-fill materials are deposited to meet low wet etch rate requirements, then etch rate requirements are satisfied, but adhesion between adjacent layers deteriorates
Solution Approach 1:
The patent uses thermal treatment to change the surface properties and chemical composition of the first gap-fill layer, creating a more adhesive surface that bonds better with the second layer. The thermal process modifies functional groups and surface energy, improving inter-layer adhesion while maintaining the etch rate benefits of the multi-layer structure
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
Significantly reduces CMP scratch defects by 50% to 75% and enhances adhesion between layers, maintaining the integrity of IC devices without strain relaxation issues associated with high-temperature annealing.
Implementation Method 1
treating the lower density gap-fill material with a thermally controlled aqueous oxidizer to enhance its hardness
Implementation Method 2
treating the lower density gap-fill material with a thermally controlled aqueous oxidizer
Data Source
AI summary
Disclosed is a method of forming a semiconductor device. The method includes providing a precursor having a substrate and protrusions over the substrate. The protrusions are interposed by trenches. The method further includes depositing a first dielectric layer over the protrusions and filling the trenches. The first dielectric layer has a first hardness. The method further includes treating the first dielectric layer with an oxidizer. The method further includes performing a chemical mechanical planarization (CMP) process to the first dielectric layer.