"Polymer Coating of Compound Semiconductors" flyer

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Polymer Coating of
Compound Semiconductors
Polymer coatings enable improved functionality for compound semiconductor devices. Besides their use as insulating layers,
polymer coatings exhibit advantages for other applications. The low dielectric constant (low-k) of polymers facilitated higher
switching frequencies of compound semiconductor devices. In turn, this enables faster data standards. On the other hand,
elevated on-chip interconnects called air bridges, are used for the same reason. To cope with reliability demands, these fragile
gold structures need rigid support. In addition, polymers such as PBO or BCB are standard for scratch protection layers, as an
overcoat to protect the wafer front side for the following back side processing.
EVG’s OmniSpray technology is a universal coating technology that accomplishes such demanding coating applications
OmniSpray® for Compound Semiconductors
Depending on the application, different types of polymer compounds are available on the market, such as epoxies, polyimides,
BCB, PBO or silicones. Varying material characteristics, hence varying process requirements, recommend OmniSpray as
universal coating technology. In addition, OmniSpray helps to reduce material usage up to 80%, considerably lowering bill of
material and working on an improved cost-of-ownership.
Advantages of EVG’s OmniSpray® for compound semiconductors:
• Reduced resist consumption (up to 80%), especially important for expensive encapsulates – such as PBO, BCB or polyimide
• Universal technology to coat polymers with largely varying solids content and viscosities
• Ideal for planarization applications (spray / spin process combination)
• Uniform coating of deep trenches and high aspect ratio features
• Special setup for high viscosity polymers
• Ideal for thick resist coating applications
Underfill Process with spray and spin
(courtesy of Agilent Technologies)
Spray coated cavities with high
EVG proprietary OmniSpray® resist
atomization nozzle
Encapsulation of compound semiconductor devices is a frequently used technology. In a wafer level approach, packages with
virtually the same size as the devices itself can be housed. Especially, consumer electronics profit from this approach, by
reduced cost, by reduced package size and higher material utilization.
Depending on the requirements of the later package, either inorganic shell materials, for vacuum and hermetic packages, or
polymer materials are used.
EVG‘s resist processing & mask aligner technology for encapsulation-based WLP features:
• Thick resist coating and patterning of sacrificial spacer layers, defining the cavity dimension and volume
• Lithographical etching mask generation for openings in inorganic films such as oxide or nitride based capping layers
• Direct patterning of photoactive polymer encapsulates, such as SU8, BCB or ShinEtsu SINR™
• Wet chemical sacrificial layer removal
• Coating and enclosure device cavities
• Etch mask patterning or lithographic opening of electrical contacts
EVG®120 – Highest flexibility for a fast paced industry
EVG®120 Fully-automated Resist Processing System up to 200mm:
• Coating of thick and thin resists such as required for optical lithography and adhesive packaging
• Spin and spray coating capability in the same bowl
• Spray Coating with X-Y Scanning or rotary motion
• Simplified operator usability and serviceability
• Reduced process qualification time
• Minimized footprint for highest fab utilization
• Fast changeover times for multiple substrate sizes
• Advanced handling and processing of bowed / warped wafers
EVG®120 Automated Resist Processing System
EVG®120 Spin Coat Module
EVG®120 Advanced Dispense Technology
Printed on paper from sustainable sources. Data, design and specifications may not simultaneously apply; or depend on individual equipment configuration, process conditions and materials and may vary accordingly. EVG reserves the right to change
data, design and specifications without prior notice. All trademarks, logos, website addresses or equipment names are registered trademarks and/or the property of EV Group or their respective owners. V01/13
Thick Resist Processing for Wafer Level Packaging

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