CMP Slurry Spray Pulsing for Uniform Pad Fluid Distribution
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Solution Overview
Problem
Conventional chemical mechanical polishing (CMP) systems face challenges in uniformly dispensing polishing fluid, leading to uneven material removal profiles and excessive fluid consumption due to continuous high flow rates, which result in wasted fluid and reduced pad lifetime.
Innovation Solution
A method and apparatus that utilize a fluid delivery assembly with adjustable nozzles capable of pulsing fluid at variable flow rates, allowing for independent control of fluid dispensing at different radial positions on the polishing pad, reducing fluid usage by up to 50% compared to conventional systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If continuous high flow rates of polishing fluid are used, then uniform fluid distribution is achieved, but fluid consumption increases significantly
Solution Approach 1:
The patent applies periodic action by pulsing the polishing fluid delivery in a controlled manner. The fluid is delivered in pulses rather than continuously, with the pulse frequency and duty cycle adjusted based on pad position. This periodic delivery method maintains uniform fluid distribution across the pad surface while significantly reducing overall fluid consumption compared to continuous high flow rates.
2Manufacturing precision
If conventional slurry tubes are used, then fluid delivery is simple, but uniform fluid distribution at low flow rates cannot be achieved
Solution Approach 1:
The patent segments the fluid delivery system into multiple independent nozzle assemblies positioned at different radial locations on the carrier assembly. Each nozzle can be independently controlled to deliver fluid to specific zones on the polishing pad. This segmentation enables precise control over fluid distribution uniformity while allowing the system to operate at lower overall flow rates compared to conventional single-tube systems.
Solution Approach 2:
The patent implements dynamics by making the fluid delivery system adjustable and adaptive. The nozzle assemblies can be positioned at different radial distances from the carrier center, and the pulse frequency and duty cycle can be dynamically adjusted based on the desired fluid distribution pattern. This dynamic capability allows the system to achieve uniform fluid distribution at low flow rates, which would be impossible with fixed conventional slurry tubes.
3Manufacturing precision
If high flow rates are used to compensate for poor distribution, then fluid accumulation at pad edge is reduced, but fluid waste increases
Solution Approach 1:
The patent applies local quality by delivering polishing fluid to different radial zones of the polishing pad with different pulse parameters. Nozzles positioned at different radial locations can operate with different duty cycles and pulse frequencies, allowing optimized fluid distribution tailored to each zone's requirements. This localized control prevents both fluid accumulation at the pad edge and excessive fluid waste, achieving uniform material removal with efficient fluid usage.
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 achieves uniform fluid distribution across the polishing pad, reducing fluid consumption while maintaining effective material removal rates and extending the life of the polishing pad by optimizing fluid delivery patterns and flow rates.
Implementation Method 1
A first flow rate of the variable flow rate is pulsed at a frequency and a duty cycle
Implementation Method 2
one or more fan jet nozzles configured to dispense pressurized fluid having a flat fan jet shape
Implementation Method 3
the polishing fluid migrates towards an outer edge of the polishing pad as the polishing pad rotates
Implementation Method 4
urging a substrate against a surface of a pad of a polishing system using a carrier assembly
Implementation Method 5
translating the carrier assembly across a surface of the pad while rotating the carrier assembly about a rotational axis
Data Source
AI summary
Methods and apparatuses for dispensing polishing fluids onto a polishing pad within a chemical mechanical polishing (CMP) system are disclosed herein. In particular, embodiments herein relate to a CMP polishing method including urging a substrate against a surface of a pad of a polishing system using a carrier assembly. A fluid is dispensed onto the pad from a fluid delivery assembly at a variable flow rate and a first flow rate of the variable flow rate is pulsed at a frequency and a duty cycle. The frequency refers to a number of pulses of the fluid at the first flow rate per rotation of the pad. The term duty cycle refers to a percentage of the pad exposed to fluid per rotation of the pad. The carrier assembly is translated across a surface of the pad while rotating the carrier assembly about a rotational axis.