Derivatized Polyamino Acid CMP Slurry for Corrosion and Planarity
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Solution Overview
Problem
As semiconductor device feature sizes shrink, achieving local and global planarity in chemical-mechanical polishing (CMP) operations becomes increasingly difficult, leading to issues like array erosion, plug and line recessing, and metal corrosion, which compromise device integrity and electrical performance.
Innovation Solution
A chemical mechanical polishing composition comprising a water-based liquid carrier, abrasive particles, and a cationic polymer with a derivatized amino acid monomer, such as derivatized polylysine, is used to inhibit metal corrosion and improve planarity during CMP operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional CMP compositions are used for metal polishing, then polishing operation can be performed, but metal corrosion and loss occur compromising device integrity
Solution Approach 1:
The patent introduces a polymer with amino acid monomers as an intermediary substance in the CMP composition. This polymer acts as a mediator between the abrasive particles and the metal surface, providing corrosion inhibition while maintaining polishing effectiveness. The polymer contains functional groups that can interact with metal surfaces to prevent corrosion during the polishing process.
Solution Approach 2:
The patent modifies the chemical composition parameters of the CMP slurry by incorporating specific amino acid monomers (such as lysine, arginine, histidine, ornithine, or a combination thereof) into the polymer structure. These parameter changes in the chemical composition enable the composition to inhibit metal corrosion while maintaining effective metal removal rates.
2Productivity
If feature sizes are reduced to continue scaling, then device density increases, but achieving planarity becomes increasingly difficult
Solution Approach 1:
The patent changes the chemical parameters of the CMP composition by incorporating amino acid-containing polymers, which alter the interaction between the slurry and the workpiece surface. This enables better control over material removal characteristics, improving planarity achievement even at reduced feature sizes where planarity control becomes more challenging.
3Reliability
If cobalt is used as interconnect material instead of tungsten, then electrical performance improves, but corrosion susceptibility increases
Solution Approach 1:
The amino acid-containing polymer acts as a protective intermediary between the CMP composition and the cobalt surface. The polymer contains basic amino acid residues that can interact with cobalt to form protective complexes, reducing corrosion susceptibility while allowing the CMP process to proceed effectively.
Solution Approach 2:
The patent modifies the chemical environment of the CMP process by introducing amino acid monomers that change the interaction dynamics with cobalt surfaces. This parameter change in the slurry composition specifically addresses cobalt's high corrosion susceptibility while maintaining the electrical performance benefits of using cobalt as the interconnect material.
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 composition effectively inhibits tungsten and cobalt corrosion while enhancing removal rates and topography, reducing defects and improving pattern wafer performance in metal CMP operations.
Implementation Method 1
a cationic polymer having a derivatized amino acid monomer... effectively inhibits tungsten and cobalt corrosion
Implementation Method 2
abrading the substrate to remove a portion of a metal or dielectric layer from the substrate
Data Source
Figure 1
AI summary
A composition comprises, consists of, or consists essentially of a polymer including a derivatized amino acid monomer unit. A chemical mechanical polishing composition includes a water based liquid carrier, abrasive particles dispersed in the liquid carrier, and a cationic polymer having a derivatized amino acid monomer unit. A method of chemical mechanical polishing includes utilizing the chemical mechanical polishing composition to remove at least a portion of a metal or dielectric layer from a substrate and thereby polish the substrate.