Polishing Liquid Composition for High-Rate CMP Surface Washability
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Solution Overview
Problem
In semiconductor manufacturing, polishing scratches and poor washability of abrasive grains on the polished surface lead to reduced polishing rates and device yield, particularly when using abrasive grains with positive zeta potential.
Innovation Solution
A polishing liquid containing abrasive grains with a positive zeta potential, a hydroxy acid, and a polymer compound with a weight average molecular weight of 3000 or more, which improves washability by reducing residual abrasive grains on the surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If abrasive grains with positive zeta potential are used to enhance reactivity and improve polishing rate, then polishing rate is improved, but washability of polished surface deteriorates due to abrasive grain remaining
Solution Approach 1:
A polymer compound with specific molecular weight (3000-1000000) acts as an intermediary between abrasive grains and polished surface. The polymer adsorbs onto the positively charged abrasive grain surfaces, providing steric hindrance that prevents abrasive grains from adhering to the polished surface while maintaining their polishing effectiveness. This mediator resolves the contradiction by enabling high polishing rate with positive zeta potential grains while preventing washability issues.
Solution Approach 2:
The invention changes the physical-chemical parameters of the polishing system by controlling the polymer compound's molecular weight within a specific range (3000-1000000). This parameter optimization ensures the polymer is large enough to provide effective steric hindrance for washability but small enough to not interfere with polishing mechanics, thereby resolving the contradiction between polishing rate and washability.
2Manufacturing precision
If content of abrasive grains is decreased to reduce polishing scratches, then polishing scratches are reduced, but mechanical action at polishing is decreased
Solution Approach 1:
The invention changes the chemical composition parameters of the polishing liquid by introducing a polymer compound with specific molecular weight characteristics. This chemical parameter change enhances the lubrication and suspension properties of the polishing liquid, allowing adequate mechanical action with reduced abrasive grain content, thus resolving the contradiction between scratch reduction and maintaining mechanical action.
3Manufacturing precision
If size of abrasive grains is decreased to reduce polishing scratches, then polishing scratches are reduced, but mechanical action at polishing is decreased
Solution Approach 1:
The invention creates a composite polishing system combining fine abrasive grains with a polymer compound of specific molecular weight. The polymer component compensates for the reduced mechanical action of fine grains by providing enhanced lubrication and sustained contact pressure, thereby maintaining adequate mechanical action while using smaller grains for scratch-free polishing.
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 enhances the washability of the polished surface, reducing residual abrasive grains and improving device yield while maintaining a high polishing rate.
Implementation Method 1
a polymer compound having at least one selected from the group consisting of a hydroxyl group and an amide group... a weight average molecular weight of the polymer compound is 3000 or more... abrasive grains are likely to remain on a polished surface after polishing... washability is poor
Implementation Method 2
a zeta potential of the abrasive grains is positive... abrasive grains having a positive zeta potential tend to have a higher polishing rate for an insulating material... abrasive grains are likely to remain on a polished surface after polishing
Data Source
AI summary
A polishing liquid containing: abrasive grains; a hydroxy acid; a polymer compound having at least one selected from the group consisting of a hydroxyl group and an amide group; and a liquid medium, in which a zeta potential of the abrasive grains is positive, and a weight average molecular weight of the polymer compound is 3000 or more.