Continuous Polishing of Refractory and Copper Metal Layers
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Solution Overview
Problem
Polishing metal-containing layers in electronic devices, particularly integrated circuits, is challenging due to the need for different polishing pads and slurries for refractory metals like tungsten and titanium nitride, which disrupts the polishing process and reduces equipment throughput.
Innovation Solution
A process that uses a selectivity agent in the polishing fluid to improve the selectivity of polishing dissimilar conductive layers over an interlevel dielectric, allowing for continuous polishing of refractory metal-containing and non-refractory metal-containing layers without significant delay or damage to the underlying dielectric.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If different polishing pads and slurries are used for refractory metals and copper, then polishing selectivity is improved, but process continuity and equipment throughput deteriorate
Solution Approach 1:
The patent employs a universal polishing pad and slurry formulation that can effectively polish both refractory metals (titanium nitride, tungsten) and copper without requiring material-specific tooling changes. This multi-functional approach maintains polishing selectivity while enabling continuous processing across different metal layers, thereby resolving the contradiction between precision and productivity
Solution Approach 2:
The invention modifies the chemical composition parameters of the polishing slurry to achieve optimal performance across multiple metal types. By adjusting slurry chemistry rather than physical pad or process parameters, the system maintains selective removal rates for different metals while ensuring process continuity and high throughput
2Manufacturing precision
If polishing process is interrupted to change pads or slurries, then material-specific polishing quality is improved, but processing time and complexity increase
Solution Approach 1:
The patent enables continuous polishing action across multiple metal layers by eliminating the need to stop and change pads or slurries. The universal polishing system maintains consistent performance on refractory metals, copper, and other conductive layers, ensuring uninterrupted processing and reducing total manufacturing time while preserving polishing quality
3Ease of operation
If same polishing pad and slurry are used for all metals, then process simplicity is improved, but polishing selectivity and material-specific quality deteriorate
Solution Approach 1:
The patent achieves universality in the polishing system where a single pad and slurry combination effectively processes multiple metal types including refractory metals and copper. This universal approach maintains material-specific polishing quality without complicating the process, as the same tools deliver optimized results across different conductive layers
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 approach enables efficient and selective polishing of multiple conductive layers with reduced removal of the underlying interlevel dielectric, improving equipment throughput and reducing complications associated with changing polishing pads and slurries.
Implementation Method 1
a polishing slurry 16 that includes a liquid medium 162 and abrasive particles 164
Data Source
AI summary
A process of forming an electronic device can include providing a workpiece. The workpiece can include a substrate, an interlevel dielectric overlying the substrate, a refractory-metal-containing layer over the interlevel dielectric, and a first metal-containing layer over the refractory-metal-containing layer. The first metal-containing layer can include a metal element other than a refractory metal element. The process further includes polishing the first metal-containing layer and the refractory-metal-containing layer as a continuous action to expose the interlevel dielectric. In one embodiment, the metal element can include copper, nickel, or a noble metal. In another embodiment, polishing can be performed using a selectivity agent to reduce the amount of the interlevel dielectric removed.