CMP Fluid Delivery Arms for Edge Polishing Uniformity
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Solution Overview
Problem
Chemical mechanical polishing (CMP) processes face challenges in achieving uniform material removal across semiconductor substrates due to uneven polishing fluid distribution, leading to non-uniform removal rates near the edge of the substrate.
Innovation Solution
A method and apparatus that utilize a first and second fluid delivery arm to control the distribution of polishing fluids on a CMP system, with the second arm delivering fluids or creating a vacuum at a radial distance greater than the first arm to manage fluid accumulation and composition near the substrate edge, thereby regulating the polishing rate and improving planarization uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If polishing fluid is dispensed from a single location towards the center of the polishing pad, then the polishing fluid can be delivered to the substrate surface, but the polishing fluid accumulates near the edge of the substrate causing uneven material removal
Solution Approach 1:
The single fluid delivery location is segmented into multiple fluid delivery locations (first and second fluid delivery arms) positioned at different radial distances from the central axis. This segmentation allows independent control of fluid delivery to different regions of the substrate, preventing accumulation at the edge while maintaining adequate fluid supply to the center.
Solution Approach 2:
Different regions of the polishing pad receive different amounts and types of polishing fluid based on their specific needs. The first fluid delivery arm delivers fluid at a first radial distance to address center region requirements, while the second fluid delivery arm delivers fluid at a second radial distance greater than the first to address edge region requirements, creating local quality variations in fluid distribution.
2Quantity of substance
If polishing fluid is dispensed evenly under the substrate, then fluid accumulation is reduced, but interaction between the substrate and retaining ring causes non-uniformities near the edge
Solution Approach 1:
The system applies local quality by delivering polishing fluid specifically to the edge region through the second fluid delivery arm positioned at a greater radial distance. This localized fluid delivery compensates for the non-uniformities caused by substrate-retaining ring interaction, ensuring that the edge region receives adequate fluid supply independent of the overall even distribution.
Solution Approach 2:
The second fluid delivery arm preemptively delivers polishing fluid to the edge region before the substrate rotates into positions where retaining ring interaction would cause fluid depletion. This preliminary anti-action counteracts the anticipated harmful effect of fluid accumulation or depletion at the edge.
3Device complexity
If a single fluid delivery arm is used, then the system structure is simpler, but the ability to control fluid distribution at different radial positions is limited
Solution Approach 1:
The fluid delivery system is segmented into multiple independent delivery arms (first and second fluid delivery arms) positioned at different radial distances from the central axis. Each arm can independently control fluid delivery to its specific region, providing precise radial position control that would be impossible with a single delivery arm.
Solution Approach 2:
The system adds a radial dimension to fluid delivery control by positioning delivery arms at different radial distances from the central axis. This dimensional differentiation allows independent control of fluid distribution across the radius of the polishing pad, transforming a single-point delivery system into a multi-point radial delivery system.
Data Source
AI summary
A method and apparatus for dispensing polishing fluids and onto a polishing pad within a chemical mechanical polishing (CMP) system are disclosed herein. In particular, embodiments herein relate to a CMP system with a first fluid delivery arm and a second fluid delivery arm disposed over the polishing pad to dispense fluid, such as a polishing fluid or water, and/or provide a vacuum pressure. The second fluid delivery arm is configured to dispense a fluid or vacuum pressure onto the polishing pad to effect the polishing rate at the edge of the substrate.