Photo-patternable Polymer Protrusions for Electrostatic Chuck
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Solution Overview
Problem
In microelectronics manufacturing, electrostatic chucks face challenges in controlling temperature uniformity and minimizing particulate contamination, which can lead to substrate deformation and yield loss due to the abrasive nature of traditional protrusions and varying contact surface characteristics.
Innovation Solution
The development of an electrostatic chuck with soft protrusions made from photo-patternable polymers, such as epoxy or polyimide-based materials, which provide a non-abrasive surface and improved manufacturability, along with a charge control layer to manage electrostatic clamping and heat transfer, while maintaining compatibility with grounded surface platen designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional protrusions are used on the electrostatic chuck surface, then contact heat conduction is improved, but particulate contamination and substrate deformation increase
Solution Approach 1:
The patent changes the material parameter of the protrusions from hard traditional materials to soft materials with durometer between 20-80 Shore A. This parameter change allows the protrusions to deform elastically under wafer clamping force, maintaining contact heat conduction while reducing particle generation through abrasive wear. The soft material property fundamentally alters the interaction mechanism between protrusions and wafer surface.
Solution Approach 2:
The patent employs composite material construction where protrusions are made from soft polymer materials (such as silicone rubber or thermoplastic elastomers) rather than traditional hard materials. This composite approach combines the thermal conductivity needed for heat transfer with the compliance of soft materials to minimize particulate contamination and protect the wafer surface.
2Temperature
If the contact surface is made rough to increase contact area, then heat transfer is improved, but manufacturing precision and particle generation worsen
Solution Approach 1:
The patent changes the surface topology parameter by using compliant soft protrusions that adapt their contact area through elastic deformation rather than relying on fixed rough surface features. The protrusions naturally conform to the wafer back surface under clamping force, achieving high contact area without requiring precision-machined rough surfaces that would generate particles during manufacturing.
3Strength
If hard protrusions are used for durable contact, then strength is improved, but abrasion and particle generation increase
Solution Approach 1:
The patent fundamentally changes the mechanical property parameter of the protrusions by selecting soft materials with durometer 20-80 Shore A. This parameter change creates a paradoxical solution where the softer material provides sufficient durability through elastic recovery while dramatically reducing abrasive wear and particle generation compared to hard materials. The soft material deforms to accommodate surface variations without generating contaminants.
4Ease of manufacture
If photo-patternable polymers are used for protrusions, then ease of manufacture is improved, but material strength may be reduced
Solution Approach 1:
The patent replaces traditional mechanical machining methods with photo-patternable polymer processing techniques. The protrusions are formed through photolithographic patterning and selective removal of polymer material, followed by curing. This substitution of manufacturing methodology achieves complex protrusion geometries with high precision and repeatability while using soft polymer materials that inherently reduce particle generation, accepting the trade-off of lower mechanical strength in exchange for manufacturing ease and contamination reduction.
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 offers improved temperature control, reduced particulate contamination, and enhanced manufacturability, resulting in more uniform heat transfer and reduced substrate deformation, thereby minimizing yield loss and improving the reliability of microelectronic devices.
Implementation Method 1
The plurality of polymer protrusions extend to a height above portions of the charge control layer surrounding the plurality of polymer protrusions to support the substrate upon the plurality of polymer protrusions during electrostatic clamping of the substrate
Implementation Method 2
During use of an electrostatic chuck, the back side of a substrate, such as a semiconductor wafer, is held to the face of the electrostatic chuck by an electrostatic force
Implementation Method 3
Heat delivered to the substrate during processing can be transferred away from the substrate and to the electrostatic chuck by contact heat conduction with the protrusions
Data Source
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AI summary
In accordance with an embodiment of the invention, there is provided a soft protrusion structure for an electrostatic chuck, which offers a non-abrasive contact surface for wafers, workpieces or other substrates, while also having improved manufacturability and compatibility with grounded surface platen designs. The soft protrusion structure comprises a photo-patternable polymer.