Novel Pressureless ZTACH® ACA for Flexible Hybrid Electronics Interconnect

Next Generation FHE – Materials and Processes

Dr. S. Manian Ramkumar

CPES 2019May 17, 2019

Traditional Material Limitations for Flexible and Advanced Technologies

Material limitations: high temperature assembly Mechanical limitations: product flexibility Manufacturing limitations: fine and ultra-fine pitch assembly bonding

Typical Electrical Interconnect Challenges

Ferromagnetic particles randomly distributed

within adhesive matrix

Magnetic field applied during curing process

creating Z-Axis columns

Columns provide electrical & thermal

conduction in Z-axis only; electrical insulation in the

X-Y plane.

Thermal dissipation due to columns outside

electrical pads

ZTACH® Pressure-Less ACA - How does it work?

https://youtu.be/Gt0l0cxGawg

BEFORE CURE:Randomly Dispersed Particles

AT 4 SECONDSParticles Align and Settle

AT 10 SECONDSColumns Form Completely

Bond Pitch100–200 microns

Bond Pitch <100 microns

Bond Pitch> 200 microns

ZTACH® Pressure-Less ACA Performance Characteristics versus No-Lead Solder and ACF randomly distributed within the matrix until processed

Parameter ZTACH® ACA No-Lead Solder ACF

Pressure Bar, kg/cm2 None Yes (Direct Bonding) >18

Curing Temperature °C 50 – 200 or UV 250 - 340 130 –150

Feature Size microns <50 <50 >150

Co-planarity concerns No Yes Yes

Precision Printing Not Required Required Not Required

Requires flux for processing No Yes No

Connection Resistance (Z-Axis) mOhms-cm 7 < 7 20-100

Insulation Resistance (X-Y) Ohms-cm >1011 <1010 >1010

Thermal Conductivity W/mK 35 - 73 60 - 100 3 - 5

End-to-End Process Time secs 300 – 600 400 - 600 750 - 1500

ZTACH® Pressure-Less ACA Value Proposition

ZTACH® Pressure-Less ACA Manufacturing Process

Reflow Oven

UV Oven

Roll-to-Roll

Batch Oven

• Minimal Preparation• Existing Deposition Processes• Existing Component Attach Methods• Magnetic Pallets – Minimal Additional Process• Standard Curing Processes – Batch Oven, Reflow Oven, UV Cure

Molex identified ZTACH® Pressure-Less ACA as an enabling technology for hybrid printed electronics.

o For use with flexible substrates including: PET, fabrics, stretchable materials and paper

o Enabling: Electronic component attach Battery attach Circuit to circuit mating Flexible display integration

Current testing/evaluations performed to date (on PET)o Demonstrated the use of ZTACH® Pressure-Less ACA for attaching components down to 0402

and 0.4mm pitch packages/connectorso Mechanical and environmental reliability testing results are equal to or better than conductive

epoxyo Attach process has been demonstrated using existing SMT line with minimal process

modifications

ZTACH® Pressure-Less Application and Qualification for Production Readiness

• ZTACH® ACA addresses complex interconnect needs for FHE:– No Pressure Required– Low Temperature Cure or UV Cure– High Density Interconnects / Multiple Component Assembly

• ZTACH® ACA process integrates into existing SMT Process (batch/reflow oven)• Strong Reliability Performance: 1000 hours at HT and HH• Opportunity for ZTACH® ACA integration is widespread• Good ZTACH® ACA initial performance in Molex test vehicles; and has wider

benefits beyond fine pitch• Products enabled with ZTACH® ACA are soon coming to the marketplace

Summary of Conclusions

ZTACH® Pressure-Less ACA Application Case Studies

• Industry:–Printed Electronics

• Requirements:–Miniaturization–Hybrid Flexible Substrates–Transparent Substrates–Rapid Cure

• Solution–Fine Pitch Capability–Low Temperature or UV Cure

ZTACH® Pressure-Less ACA Case Studies

Challenge: Mylar/Kapton substrates under high temperature curing incurred warpage; also the fine pitch requirements were not achievable.

Solution: ZTACH® ACA UV curable formulation was used to eliminate warpage, fine pitch requirement was achieved and attaching on flexible substrate was not an issue. Demonstrated ability to heat cure at 70° C to eliminate warpage for substrates that are not transparent.

• Industry–Medical Devices

• Requirements: –Miniaturization–Flexible Substrates/Delicate Components

• Solution–Fine Pitch Capability–Pressure-less–Low Temperature or UV Cure

ZTACH® Pressure-Less ACA Case Studies

Challenge: Transducers are very thin, very fine pitch and temperature sensitive. Transducers must be interconnected to flexible substrates for use in ultrasound diagnostic capsules. Previous tested materials were unsuccessful in making fine pitch interconnects.

Solution: Collaborated with customer in developing fine pitch interconnections of transducers to flexible substrate with low temperature curing. ZTACH® ACA was the only interconnect material that was successful. SunRay is identified as their Industrial Supplier.

Customer Requirement: Small Form Factor & Fine Pitch Capability

Courtesy: Purdue University

ZTACH ® Pressure-less ACA Biomedical Case Study: Small Form Factor

ZTACH® Pressure-Less ACA opens new applications for the Medical Device Market

Glaucoma is predicted to affect about 60.5 million people, of which 4.5 million will become blind in both eyes

Implanted Ocular Device for Studying Glaucoma

Source: Implantable Wireless Telemetry Boards for In Vivo Transocular Transmission, IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, DECEMBER 2008

ZTACH® Pressure-Less ACA 3D Packaging Medical Case Study

ZTACH® Pressure-Less ACA Case Studies

• Industry:–ALL

• Requirements:–3D Stacked Chip Stacking–Small Form Factors–Miniaturization

• Solution–Reverse 3D Chip Stacking–Fine Pitch Capability

ZTACH® Pressure-Less ACA’s Reverse 3D- Stacking Improves efficiency,

Lowers Cost & Improves Reliability

Challenge: Current process of wire bonding is very complex. Heat build up is of great concern.

Solution: ZTACH® ACA allows for direct connection from chips to host substrate, a compact design, one direction stacking and the ability to add heat sink for thermal dissipation

Thank You...

Madhu Stemmermann, SunRay Scientific LLC

CEOmadhu@sunrayscientific.com

Dr. Martin Anselm, RIT Director of CEMAmkamet@rit.edu