Ceria CMP Composition for Auto-Stop Patterned Oxide Polishing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current chemical mechanical polishing (CMP) solutions lack an effective auto-stop function, leading to high polishing rates on both blank and patterned silicon wafers, resulting in excessive trench loss and reduced planarization efficiency.
Innovation Solution
A chemical mechanical polishing solution comprising cerium oxide abrasive particles, hydroxylamine, and optional additives like 4-hydroxybenzoic acid or salicylhydroxamic acid, with controlled pH and solid content, to achieve a lower polishing rate on blank wafers and a higher rate on patterned wafers, thereby enabling auto-stop functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If cerium oxide is used as polishing particles to improve polishing rate, then polishing rate increases, but trench loss increases and planarization efficiency decreases
Solution Approach 1:
The patent changes the chemical composition parameters of the polishing solution by adding hydroxylamine and specific additives (4-hydroxybenzoic acid or salicylhydroxamic acid) to control the polishing chemistry. This modifies the reaction mechanisms between cerium oxide and the dielectric material, enabling selective removal rates that achieve auto-stop function - where polishing rate automatically decreases when step height becomes small, thereby reducing trench loss while maintaining overall planarization efficiency
Solution Approach 2:
The patent creates a composite polishing solution system combining cerium oxide abrasive particles with hydroxylamine and organic additives. This composite chemical system produces synergistic effects where the additives modify the polishing mechanism to achieve differential removal rates based on step height, resolving the contradiction between high polishing rate and low trench loss
2Productivity
If polishing rate on blank wafer is increased to improve planarization efficiency, then planarization efficiency improves, but trench loss on patterned silicon wafer increases
Solution Approach 1:
The patent achieves local quality differentiation in polishing behavior through chemical mechanisms. The polishing solution exhibits different effective polishing rates in different local conditions: high removal rate where step height is large (blank areas needing planarization) and low removal rate where step height is small (patterned areas). This chemical local quality control enables simultaneous achievement of high planarization efficiency and low trench loss
3Loss of substance
If auto-stop function is implemented to reduce trench loss, then trench loss decreases, but polishing process complexity increases
Solution Approach 1:
The patent implements self-service auto-stop function through chemical mechanisms in the polishing solution itself. The hydroxylamine and additives create a self-regulating polishing chemistry that automatically adjusts removal rates based on step height without requiring external detection or control systems. The solution itself provides the control function, eliminating the need for complex endpoint detection devices or process control systems
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 solution effectively inhibits polishing on blank wafers while maintaining high rates on patterned wafers, reducing trench loss and enhancing planarization efficiency without the need for additional detection devices.
Implementation Method 1
chemical mechanical polishing (CMP) has become the most effective and mature planarization technology
Implementation Method 2
The chemical mechanical polishing solution comprises cerium oxide abrasive particles, hydroxylamine (NH2OH) and water
Data Source
AI summary
Disclosed is a chemical mechanical polishing solution containing water, cerium oxide abrasive particles and hydroxylamine, which can also increase the removal rate of patterned silicon dioxide with further addition of 4-hydroxybenzoic acid or salicylhydroxamic acid.