UV Curable CMP Pads via Photocurable Printing
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Solution Overview
Problem
Conventional polishing pads used in chemical mechanical polishing (CMP) processes for electronic device manufacturing suffer from instability in material properties over a wide temperature range, leading to reduced performance and increased defectivity such as scratches on the substrate surface.
Innovation Solution
A photocurable printing composition comprising a urethane acrylate oligomer with specific viscosity and glass transition temperature ranges, combined with acrylate monomers and a photoinitiator, is used to form polishing pads with improved stability and performance through additive manufacturing, providing a polishing pad with enhanced planarity and reduced dishing and erosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If polishing pads are formed of harder materials to provide superior local planarization performance, then polishing performance is improved, but defectivity increases such as undesirable scratches on substrate surface
Solution Approach 1:
The patent changes the material parameters by using a softer polishing pad material with controlled hardness (storage modulus) that maintains stability across temperature ranges. This parameter change allows achieving acceptable planarization performance while reducing defectivity caused by overly hard materials.
Solution Approach 2:
The patent employs composite material structures combining different polymer components (polyurethane, polyester, acrylic) with specific ratios to create a polishing pad that balances hardness and compliance. This composite approach enables simultaneous achievement of planarization performance and reduced scratch generation.
2Ease of manufacture
If conventional polishing pads are used, then they are available and cost-effective, but they soften at high temperatures reducing their ability to maintain desirable hardness over a wide temperature range
Solution Approach 1:
The patent modifies the material composition parameters by incorporating heat-resistant polymer components and optimizing cross-linking density to raise the glass transition temperature. This enables the polishing pad to maintain its hardness and mechanical properties across a wide temperature range from -50°C to 150°C.
Solution Approach 2:
The patent uses composite polymer systems combining thermoplastic and thermosetting components that provide both processability and thermal stability. The composite structure maintains material integrity and hardness stability under varying temperature conditions while remaining manufacturable.
3Object-generated harmful factors
If softer polishing pads are used to reduce defectivity and scratches, then substrate surface quality is improved, but local planarization performance deteriorates
Solution Approach 1:
The patent optimizes the hardness parameter (storage modulus) to a specific range that provides compliance for reduced scratching while maintaining sufficient rigidity for effective planarization. The controlled hardness range achieves the balance between gentleness on substrate and effectiveness on polishing.
Solution Approach 2:
The patent introduces dynamic compliance through viscoelastic material design that adapts its effective hardness during operation. The material exhibits different mechanical responses under varying contact pressures and temperatures, providing softness during contact to reduce scratches while maintaining structural integrity for planarization.
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 maintains consistent material properties and performance over a wide temperature range, reducing defects like scratches and improving local planarization, thereby enhancing the reliability and performance of CMP processes.
Implementation Method 1
The photocurable printing composition further includes a photoinitiator
Data Source
AI summary
The disclosure generally relates to polishing pads, methods of manufacturing polishing pads, and formulations for manufacturing polishing pads, and more particularly, to polishing pads used for chemical mechanical polishing (CMP) of a substrate in electronic device processing. In one aspect, a photocurable printing composition containing photopolymerizable compounds and photopolymerization initiator is provided. The photocurable printing composition comprises a urethane acrylate oligomer having a functionality of 2 or more, a nominal viscosity greater than 20,000 cP at 60 degrees Celsius, and a glass transition temperature (Tg) of −4 degrees Celsius or greater, the urethane acrylate oligomer present from about 20% to about 60% by weight based on a total weight of the photopolymerizable compounds. The photocurable printing composition has a viscosity of 20 centipoise or higher at 70 degrees Celsius.