CMP Slurry Composition for Fast Tungsten and Cobalt Planarization
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Solution Overview
Problem
There is a need for a chemical-mechanical polishing composition and method that can efficiently polish semiconductor substrates containing conductive metals like tungsten and cobalt, achieving a flat and defect-free surface while maintaining high speed and preventing corrosion.
Innovation Solution
A composition comprising silica particles with a functional group covalently bonded to their surface and a silane compound, along with optional additives such as an oxidizing agent and organic acid, is used for chemical-mechanical polishing. This composition is designed to effectively polish semiconductor substrates, particularly those with tungsten and cobalt, by forming a protective film and controlling the polishing process to prevent defects and corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional CMP compositions are used for polishing tungsten and cobalt, then polishing can be performed, but material removal rate is insufficient and surface defects occur
Solution Approach 1:
The patent modifies the chemical composition parameters of the CMP slurry by incorporating specific organic acids (carboxylic acid, sulfonic acid, or phosphonic acid) and their derivatives at controlled concentrations (0.01-5 wt%). This chemical parameter change enables effective removal of tungsten and cobalt while maintaining surface quality, resolving the contradiction between material removal rate and surface defect rate
Solution Approach 2:
The invention creates a composite polishing system combining multiple components: abrasive particles, binding agents, and specifically selected organic acid additives. This composite formulation works synergistically to achieve both high material removal rate and low surface defect rate for conductive metal layers, transforming the polishing composition into a multi-functional system that addresses both productivity and precision requirements
2Productivity
If polishing speed is increased for efficient removal of tungsten and cobalt, then productivity improves, but surface defects and corrosion increase
Solution Approach 1:
The organic acid additives act as intermediary substances that mediate between the abrasive particles and the conductive metal surfaces (tungsten and cobalt). These intermediaries facilitate controlled chemical reactions that enable high-speed polishing while simultaneously protecting the surface from defects and corrosion, thus resolving the contradiction between polishing speed and surface quality
Solution Approach 2:
The patent adjusts the pH and chemical composition parameters of the polishing slurry by adding specific organic acids. This parameter optimization allows the system to operate at higher polishing speeds while maintaining surface integrity and corrosion resistance, effectively resolving the trade-off between productivity and reliability
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 proposed solution enables efficient polishing of semiconductor substrates with conductive metals, achieving high speed and reducing surface defects, while maintaining a defect-free and corrosion-resistant surface.
Implementation Method 1
chemical mechanical polishing
Implementation Method 2
silica particles having a functional group represented by general formula (1)... —COO−M+ (1)
Implementation Method 3
silane compound... Si(OR1)4 (2)
Implementation Method 4
silane compound... SiR2m(OR3)n(R4—NR52)p (3)
Implementation Method 5
oxidizing agent... suppress the corrosion of tungsten and cobalt
Data Source
AI summary
Provided are a chemical-mechanical polishing composition and a chemical-mechanical polishing method capable of polishing a semiconductor substrate containing a conductive metal such as tungsten or cobalt flatly and at high speed as well as reducing surface defects after polishing. The composition for chemical-mechanical polishing contains (A) silica particles having a functional group represented by general formula (1) and (B) a silane compound. —COO-M+ . . . (1) (M+ represents a monovalent cation.)