PCMI BOSTON. October 11, 2011 "3D Etching Process of the Hybrid Laminate of Metal Foils on Polyimide Film to Build Ultra Thin Connectors for High Density Flexible Circuits Yosuke Kobayashi Dominique Numakura Hirai Seimitsu Kogyo
1. Introduction of Hirai Seimitsu Kogyo Corp. Foundation : October 28 th, 1967 in Osaka, Japan Total Staff : 420 employees Customers : Over 1,000 per year Services : -Chemical Milling Process for Metal and Polyimide -Lamination Process (Metal + Tape ) -Bonding Process (Thermal Pressure bonding, Spot welding) -Plating Process and Surface treatment -Machining Process (Laser, Wire Cut)
Lamination Heat Spreader with Various tape QFN Leadframe with Polyimide film 3-Dimensional Etching Process Depth : 0.2mm Depth : 0.05mm
Etching & Laser for PI film and Metal +PI doc Half Etching Through Hole Cu 0.4mm t PI 0.025mm t Polyimide film (0.025 0.125mmt ) Copper + Polyimide film
2. Basic Concept of UTF Connector UTF Connection Systems provide extremely low height connections smaller than 0.3 mm on the rigid board surface for high density flexible circuits using micro bump arrays. The connector devices have been developed utilizing the lamination and etching capabilities of Hirai Seimitsu.
Why is it demanded? Currently, Mobile electronics have been consuming a lot of connectors for the termination of high density flexible circuits. Cellular phones, Smart phones Digital cameras MP3 Notebook PC, Tablet PC DVD players Navigators Display devices Sensor devices Medical devices
Tear down of a cellular phone
Several termination technologies have been developed for the repeated connection of the high density flexible circuits. However, they have limitations to reduce the height and pitches. It will be a geometrical limitations for the next generation electronics packaging. FFC connectors BTB connectors
Traditional Technologies(1) FFC Connectors Height: > 0.7 mm Traditional Technologies (2) BTB Connectors Height: > 1.0 mm
Current termination devices of the flexible circuits have been occupying the largest areas and volume on the SMT circuit boards. The connector manufacturers have been trying to reduce the termination pitches and the height of the connections, however, there could be mechanical limitations if they will stay with the same termination concepts. New alternative termination technologies will be demanded in the near future for higher circuit densities with smaller heights.
## UTF Connection will provide the thinnest solution for the repeatable termination of the high density flexible circuits designed for the next generation portable electronics.
Stiffener Board UTF Connector Micro Bump Substrate Flexible Circuit Via Hole Rigid Circuit Board Connected Basic Mechanisms of UTF Connectors
Features of UTF Connection
Basic Mechanisms UTF Connector Flexible Circuits TH Multi-layer Board
Examples of the Pad Array
UTF Connectors could have many varieties to satisfy different requirements by applications.
UTF Connector Flexible Circuits Rigid Board Hooking Mechanisms of UTF Connector
Flex circuit UTF Connector Hinge Rigid board Variations for the Terminations of Hinge Type UTF Connector
Hinge Construction Large bumps for guide & fixing Fixing frame Flexible hinge Fixing bumps Metal bump Metal bump array Metal Stiffener Base film Metal bump
UTF Connector with hinge Hinge Flex Circuit Rigid Board Connection of the Hinge Construction
3. Manufacturing of UTF Connector Manufacturing specialties for UTF Connecters How to build Mt. Fuji (truncated cone) shape bump arrays? The basic idea was to utilize the side etching effects.
3. Manufacturing of UTF Connector Polyimide Cut Etching for metal on polyimide tape Half etching Bump forming Specialties of the Etching Process for UTF Connecter
Challenges of the Manufacturing Process 1. To etch different metal foils with different thicknesses in one process. 2. One side etching for thick metal foils. 3. To control the amount of side etching to generate appropriate slope shapes for the micro bump arrays. 4. To minimize the side etching to make accurate perimeters of the stiffener metals. 5. To conduct half etching for stiffener metals. 6. To remove polyimide resin from hook metal surface. 7. To cut polyimide film substrate with good alignment.
Process Flow 1) First Lamina-on (Metal with PI ) Metal Foil Polyimide Film (with Adhesive Layers )
Process Flow 2) Second Lamina-on *Different metal foil with different thickness
Process Flow 3) Differen-al 3D Etching Process
Process Flow 4) Laser CuIng
4. Result, UTF Connector *The differential 3D etching was successful to generate micro bump arrays with appropriate slopes for the UTF Connectors. *The etching process is also capable to make perimeters of the stiffeners and fixing frames. *The manufacturing processes do not need expensive pressing dies.
After chemical etching
Shape of the micro bumps
Cross-section photo of the Mt. Fuji shape micro bumps
Flex termination by hinge type UTF Connector
5. Conclusion 1. The differential 3D etching process is capable to produce UTF Connectors with various varieties of the hybrid laminates. 2. The etching process realizes under 0.3 mm height connections for high density flex circuits in thin portable electronics. 3. It can be a low cost solution for both of the prototype production and volume production because of all chemical process eliminating assembling process and expensive tooling.
UTF Connection is a foundation for the next generation electronics packaging technologies. The differential 3D etching process will be the main manufacturing process of the connectors. Thank you very much for your attentions. Hirai Seimitsu Kogyo Corp. http://www.hirai.co.jp DKN Research LLC http://www.dknresearch.com