Structured Diamond Abrasive for CMP Pad Conditioning
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Solution Overview
Problem
Current CMP conditioning disks with embedded diamond particles suffer from irreproducibility and defects due to Gaussian distribution of particle sizes and potential for particle breakage or dislodgment, leading to variations in polishing rates and increased defect rates in semiconductor and other precision industries.
Innovation Solution
The development of precision microfabricated or nanofabricated diamond abrasive articles with tightly controlled placement and geometry of diamond geometrical protrusions, such as spikes or pyramids, to ensure uniform and predictable abrasive action, reducing particle loss and enhancing reproducibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If diamond grit particles are embedded in a metal layer using electroplating, then the conditioning disk can be manufactured with relatively simple process, but the particle size distribution follows Gaussian distribution with 15-20% standard deviation leading to poor uniformity in pad conditioning
Solution Approach 1:
The patent replaces the electroplating process with a magnetic field-based assembly system. Magnetic fields are used to position diamond particles at specific locations on the conditioning disk surface, enabling precise control of particle placement and eliminating the Gaussian distribution problem inherent in electroplating methods.
Solution Approach 2:
The patent introduces a magnetic field as an intermediary mechanism to mediate the placement of diamond particles. This magnetic intermediary enables precise positioning and controlled distribution of particles, achieving uniformity that cannot be obtained through direct electroplating alone.
2Duration of action of moving object
If larger diamond particles are used to increase effective work life, then the number of wafers that can be processed increases, but the particles may break or be dislodged causing large scratches and defects on polished surfaces
Solution Approach 1:
The patent applies local quality by using smaller diamond particles (with controlled size distribution) that are precisely positioned in specific locations on the conditioning disk. This local precision control allows the use of smaller, more stable particles that won't break or dislodge, thereby reducing defect rates while maintaining effective work life through optimized particle distribution.
Solution Approach 2:
The patent changes the particle size parameter from large particles to smaller particles with a controlled narrow size distribution. This parameter change, combined with precise placement control, reduces particle breakage and dislodgment while maintaining conditioning effectiveness, thus reducing defect rates.
3Manufacturing precision
If diamond particles are tightly controlled in size and placement through precision microfabrication, then uniformity and reproducibility of CMP process is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent replaces complex precision microfabrication mechanical processes with a magnetic field-based assembly system. This substitution achieves tight control of particle size and placement through magnetic field manipulation rather than complex mechanical fabrication, thereby improving uniformity while reducing overall device complexity.
Solution Approach 2:
The patent uses magnetic fields as an intermediary to achieve precise particle placement without requiring complex microfabrication machinery. This magnetic intermediary simplifies the fabrication process while maintaining high manufacturing precision in particle distribution.
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
This approach results in highly controlled abrasive action, extended tool life, and reduced defect rates by maintaining uniformity and reproducibility in CMP processes, suitable for applications in semiconductor, optical, and MEMS manufacturing.
Implementation Method 1
Some embodiments described herein are designed to produce precision microfabricated or nanofabricated abrasive articles or polish pad conditioners with a plurality of raised geometrical protrusions which produce abrasive action or material removal when placed into contact with a target surface
Data Source
AI summary
The present invention describes a microfabricated or nanofabricated structured diamond abrasive with a high surface density array of geometrical protrusions of pyramidal, truncated pyramidal or other shape, of designed shapes, sizes and placements, which provides for improved conditioning of CMP polishing pads, or other abrasive roles. Three methods of fabricating the structured diamond abrasive are described: molding of diamond into an array of grooves of various shapes and sizes etched into Si or another substrate material, with subsequent transferal onto another substrate and removal of the Si; etching of an array of geometrical protrusions into a thick diamond layer, and depositing a thick diamond layer over a substrate pre-patterned (or pre-structured) with an array of geometrical protrusions of designed sizes, shapes and placements on the surface.