CMP Slurry with Phosphoric Acid and Anionic Polymer for Dishing Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The CMP process for semiconductor devices experiences excessive dishing during the polishing of silicon oxide layers, leading to performance and reliability issues due to high polishing selectivity, which causes excessive polishing of the silicon oxide layer and leaves the silicon nitride layer untouched.
Innovation Solution
A CMP slurry comprising a polishing abrasive, a linear anionic polymer, a compound with a phosphoric acid group, and water, with a polishing speed ratio of 30:1 to 50:1 for silicon oxide to silicon nitride, which inhibits excessive polishing of the silicon nitride layer and allows controlled polishing of the silicon oxide layer, reducing dishing generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high polishing selectivity is achieved to polish silicon oxide layer effectively, then polishing rate to silicon oxide layer is improved, but dishing is generated due to excessive polishing of silicon oxide layer
Solution Approach 1:
The patent changes the chemical composition parameters of the CMP slurry by incorporating specific compounds (phosphoric acid group compounds, linear anionic polymers, and metal ion complexes) to adjust the polishing characteristics. This allows achieving a balanced polishing rate that maintains high productivity while preventing excessive polishing that causes dishing
Solution Approach 2:
The patent uses a composite slurry formulation combining multiple functional components: polishing abrasives, phosphoric acid group compounds for chemical reaction, linear anionic polymers for adhesion control, and metal ion complexes for selective polishing enhancement. This composite approach enables simultaneous achievement of high polishing rate and reduced dishing by coordinating the effects of different materials
2Productivity
If polishing selectivity is increased to achieve low polishing rate to silicon nitride layer, then selective polishing of silicon oxide layer is improved, but silicon nitride layer is excessively protected leading to dishing
Solution Approach 1:
The patent adjusts the chemical parameters of the slurry by controlling the concentration ratios of phosphoric acid group compounds to linear anionic polymers, and optimizing metal ion content. These parameter changes fine-tune the polishing selectivity to achieve 30:1 to 50:1 ratio between silicon oxide and silicon nitride, preventing both excessive polishing and excessive protection
Solution Approach 2:
The patent introduces metal ion complexes as intermediary substances that mediate the interaction between the slurry and both silicon oxide and silicon nitride layers. These metal ions act as catalysts that enhance the chemical reaction with silicon oxide while having limited effect on silicon nitride, achieving balanced selectivity without extreme protection
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 CMP slurry effectively reduces dishing generation while maintaining selective polishing of the silicon oxide layer, preventing over-polishing and improving the planarization process, thereby enhancing the performance and reliability of semiconductor devices.
Implementation Method 1
a polishing abrasive
Implementation Method 2
a linear anionic polymer, a compound including a phosphoric acid group
Data Source
AI summary
The present invention relates to a CMP slurry that is able to reduce dishing generation, when it is applied to polishing or planarization of silicon oxide layer, for example, and a polishing method.The CMP slurry includes a polishing abrasive, a linear anionic polymer, a compound including a phosphoric acid group, and water, and the ratio of CMP polishing speed to a silicon oxide layer: CMP polishing speed to a silicon nitride layer is 30:1 to 50:1.