Foamed CMP Slurry Delivery for Lower Waste Polishing
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Solution Overview
Problem
Significant slurry waste occurs during chemical mechanical polishing (CMP) processes, leading to inefficiencies in material removal rate, planarization rate, and surface quality due to excessive use of polishing liquid that is not effectively utilized.
Innovation Solution
A system and apparatus that produces a polishing foam by mixing polishing liquid, surfactant, and gas to create a foam slurry, which is dispensed onto the substrate, reducing waste and maintaining the effectiveness of the CMP process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If slurry is continuously supplied over the polishing pad, then the polishing process can proceed, but a considerable amount of slurry is wasted and not effectively utilized
Solution Approach 1:
The patent changes the physical state of the slurry from liquid to foam by incorporating gas bubbles. This parameter change increases the slurry's viscosity and allows it to remain on the substrate surface longer, improving utilization efficiency and reducing waste while maintaining polishing productivity
Solution Approach 2:
The patent introduces a foam structure as an intermediary between the liquid slurry and the substrate. The foam acts as a carrier that delivers the slurry components more effectively to the polishing interface, reducing the amount of slurry needed and minimizing waste
2Quantity of substance
If polishing liquid is used in large quantities, then the polishing process can be maintained, but material removal rate and planarization rate are inefficient
Solution Approach 1:
By transforming the slurry into a foam state, the patent changes its rheological properties including viscosity and surface tension. This allows the polishing liquid to be applied in smaller quantities while achieving better material removal rates and planarization efficiency
Solution Approach 2:
The patent utilizes gas-liquid foam structure to deliver the polishing slurry. The pneumatic component (gas bubbles) provides better distribution and retention of the liquid slurry on the substrate, improving the efficiency of material removal with reduced liquid consumption
3Quantity of substance
If conventional liquid slurry is used, then the polishing process proceeds, but surface quality is compromised due to excessive slurry use
Solution Approach 1:
The foam structure changes the delivery characteristics of the slurry, providing more controlled and uniform distribution on the substrate surface. This improves surface quality by preventing excessive slurry accumulation and ensuring consistent polishing across the surface
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 use of polishing foam increases viscosity, allowing more slurry to remain on the substrate, thereby improving material removal rate, planarization rate, and surface quality while reducing slurry waste.
Implementation Method 1
creating a polishing foam using a polishing liquid, a surfactant, and a gas
Implementation Method 2
creating a polishing foam using a polishing liquid, a surfactant, and a gas
Implementation Method 3
rotating the polishing pad using the platen to polish the substrate
Implementation Method 4
a polishing liquid or slurry, which may include an abrasive and at least one chemically reactive agent
Data Source
AI summary
Embodiments of the present disclosure generally relate to dispensing slurry as a foam in chemical mechanical polishing systems. A polishing apparatus includes a platen, a polishing pad having a polishing surface and disposed on the platen, a carrier head configured to press a substrate onto the polishing surface, a spray bar assembly configured to dispense a polishing foam onto the polishing surface, and a controller coupled to the polishing apparatus and configured to cause the polishing apparatus to: place a substrate on the polishing surface using the carrier head, create a polishing foam using a polishing liquid, a surfactant, and a gas using the spray bar assembly, use the spray bar assembly to dispense the polishing foam onto the polishing pad, and rotate the polishing pad using the platen to polish the substrate.