CMP Slurry with Amino-Hydroxyl Compound for Step Height Control
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Solution Overview
Problem
Current chemical mechanical polishing slurries for STI formation fail to maintain a small step height between insulating films and stop films, leading to excessive removal of insulating films and decreased reliability of semiconductor elements due to non-uniform polishing and high polishing rates.
Innovation Solution
A slurry comprising abrasive grains such as cerium oxide and a compound with an amino group having a pKa of more than 9 and multiple hydroxyl groups, along with water, is used to achieve improved planarization and reduced step height between insulating films and stop films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the polishing rate of insulating film is high to efficiently remove excess film, then the polishing efficiency is improved, but the insulating film on concave parts is excessively removed causing dishing phenomenon
Solution Approach 1:
The patent applies local quality control by using a compound with specific functional groups that creates different polishing characteristics in different regions. The compound's chemical properties enable the slurry to selectively control the polishing rate based on local conditions (convex vs. concave regions), allowing efficient removal from convex areas while protecting concave areas from excessive removal.
Solution Approach 2:
The compound with specific functional groups acts as an intermediary between the abrasive grains and the films being polished. This intermediary substance modulates the interaction between the slurry and different film types/regions, enabling efficient polishing where needed while preventing excessive removal in sensitive areas, thus resolving the contradiction between polishing efficiency and film thickness uniformity.
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 slurry effectively minimizes the step height between insulating films and stop films, enhancing the planarization performance and reliability of semiconductor elements by balancing adsorption strength and reducing overpolishing.
Implementation Method 1
The slurry comprises abrasive grains (a), compound (b) having an amino group having a pKa of more than 9 and not less than 3 hydroxyl groups
Implementation Method 2
A slurry comprising abrasive grains such as cerium oxide and a compound with an amino group having a pKa of more than 9 and multiple hydroxyl groups, along with water, is used to achieve improved planarization
Data Source
Figure 1~4
AI summary
The present invention provides a slurry for chemical mechanical polishing, containing abrasive grain (a), compound (b) having an amino group having a pKa of more than 9, and not less than 3 hydroxyl groups, and water.