¬¬Mechanically Punched Micro Via Fabrication Process in LCP Substrate for RF-MEMS and Related Electronic Packaging Applications

1. Understanding Micro Via Fabrication by Mechanical Punching in Liquid Crystal Polymer (LCP) Substrate for RF-MEMS and Related Electronic Packaging Applications Mohammad K. Chowdhury, 1 Li Sun, 2 Shawn Cunningham, 2 and Ajay P. Malshe 1* 1 University of Arkansas, Fayetteville, AR 72701 2 WiSpry Inc., Irvine, CA 92618 * Contact E-mail: [email_address] IMAPS 2009 November 3 rd , 2009

4. Driver Applications: Tuesday, November 03, 2009 IMAPS 2009, San Jose McEnery Convention Center www.morgantechnicalceramics.com www.smalltimes.com www.ec.europa.eu – ANASTASIA Project Transreceiver Base Station for Cell Phone

6. Different Material Candidates for the Substrate: Tuesday, November 03, 2009 IMAPS 2009, San Jose McEnery Convention Center LCP - ULTRALAM 3850 [1] LTCC - DuPont 951 Green Tape [2] Kapton - Dupont HN100 [3] Peel Strength ( lbs/in) 8.52 12 7.2 Tensile strength ( MPa) 200 320 231 Tensile Modulus(GPa) 2.255 120 2.0 Density ( g/cm 3 ) 1.4 3.1 1.42 CTE ( ppm/°C) 17 (X & Y axis) 150 (Z-axis) 5.8 20 Melting Temp. (°C) 335 738 360 Thermal Conductivity ( W/m/°K) 0.2 3.3 1.09 Dielectric Constant @ 10 GHz, 23°C 2.9 7.1 3.5 Dissipation Factor/Loss Tangent @ 10 GHz, 23°C 0.0025 0.005 0.002 Volume Resistivity ( Mohm) 1x10 12 1x10 14 1x10 17 Dielectric Breakdown Strength (V/mil) 3500 1000 5200 Chemical Resistance 98.7% - 95% Water Absorption (23°C, 24 hrs) 0.04% - 2.8%

7. Different Techniques for µ-Via Fabrication : Tuesday, November 03, 2009 IMAPS 2009, San Jose McEnery Convention Center Via Diameter, Substrate Material Via Pitch Via Shape in Z-axis Aspect Ratio Damage to Substrate Speed Cost/Via Mechanical Punching 30µm, Mylar [8] - Uniform Low - 3:1 [8] Relatively Smooth Surface of the Via Wall High Very Low [11] Mechanical Drilling 100µm, PCB [6] 50µm [6] Almost Uniform Low Very Rough Surface of the Via Wall Slow Low [11] Laser Drilling (CO 2 , YAG, YVO 4 Excimer) 25 to 75 µm, Polyimide - CO 2 , [4] 10 to 15 µm, Ceramics, PVA, Polystyrene, & Pyrex Glass - YAG –[5] 25µm, LCP - YVO 4 , [7] - Very Uniform [8, 12] Very High -20:1 [13] Carbon Residue Leftover [12] Smooth Surface of the Via Wall [13] Slow Low [4] Plasma Etching 50 µm, Kepton [10] - Very Uniform High Very Smooth Surface of the Via Wall Very Slow Expensive E-beam Machining 65 µm, Green Tape [9] 200 µm [9] Very Uniform [9] High [9] Very Smooth Surface of the Via Wall [9] Very Slow Extremely Expensive

10. How The Punching System Works? Tuesday, November 03, 2009 IMAPS 2009, San Jose McEnery Convention Center Die Bushing LCP Copper Copper Pin LCP Copper Copper Before Punching Copper Copper LCP After Punching Copper Copper LCP APS 8718 Automatic Punching System Pacific Trinetics Corporation 6” x 6” Sample Holder Punch Pin Holder & Die Bushing

13. Punching Directions: Tuesday, November 03, 2009 IMAPS 2009, San Jose McEnery Convention Center

15. Mechanism of LCP film Z-axis Expansion : Tuesday, November 03, 2009 IMAPS 2009, San Jose McEnery Convention Center a) Via Pitch Via Diameter b) Via Diameter Via Pitch d) c)

25. [1] MSDS, ULTRALAM ® 3000 - Liquid Crystalline Polymer Circuit Material, Rogers Corporation, Arizona, USA [2] Low Temperature Cofire Dielectric Tape Technical information, 951 Green Tape TM , DuPont Microcircuit Materials [3] Summary of Properties for Kapton® Polyimide Film, DuPont Microcircuit Materials [4] Jim Morrison, Ted Tessier, and Bo Gu, “A Large Format Modified TEA CO 2 Laser Based Process for Cost Effective Small via Generation,” MCM Proceedings, pp 369-377, 94 [5] Vijay V. Kancharla, Kira K. Hendricks, and Shaochen Chen, “Micromachining of packaging materials for MEMS using laser” Micromachining and Microfabrication Process Technology VII, Proceeding of SPIE, Vol. 4557, pp 220-224, 2001 [6] Brian J. McDermott, and Sid Ttyzbiak, “Practical application of photo-defined micro-via technology,” 3 rd International Symposium on Advanced Packaging Material, pp 24-28, 1997 [7] Mingwei Li, Hix Ken, Dosser Larry, Hartke Kevin, and Blackshire Jim, “Micromachining of Liquid Crystal Polymer film with Frequency converted diode-pumped Nd: YVO 4 Laser” Photon Processing in Microelectronics and Photonics II, Proceeding of SPIE, Vol. 4977, 2003 [8] Gunter Hagen, and Lars Rebenklau, “Fabrication of smallest vias in LTCC tape,” Electronics Systemintegrations Technology Conference, Dresden, Germany, pp 642-647, 2006 [9] M.A. Sarfaraz, C. Long, and You-Wen Yau, “Enhanced MCM-C Packaged Performance by Formation of improved 3-D interconnections,” Electronic Components and Technology Conference, Proceedings, pp 1067-1071, 1993 [10] James Keating, and Robert Larmouth, “Microvias and Flex – An enabling MCM-L Technology,” International Conference on Multichip Modules and High Density Packaging, pp 342 -384, 1998 [11] T. G. Tessier, and Bill Adams, “Mechanical Punching of Through-Holes in Thin Laminates for Higher Density MCM-L Fabrication” MCM Proceedings, pp 173-181, 1994 [12] Dane Thompson, “Characterization and Design of Liquid Crystal Polymer (LCP) Based Multilayer RF Components and Packages” PhD dissertation 2006, Georgia Tech. [13] T. M. Yue, and K.C. Chan, “Laser Drilling of Liquid Crystal Polymer Composites” Polymer Composites, Vol.19, No.1, 1998 References: Tuesday, November 03, 2009 IMAPS 2009, San Jose McEnery Convention Center

26. Thank You ! Questions, Comments & Suggestions

28. Plasma Cleaning of LCP Residual Removal Tuesday, November 03, 2009 IMAPS 2009, San Jose McEnery Convention Center Before O 2 Plasma Cleaning LCP Burr Copper Etched Out After O 2 Plasma Cleaning Before O 2 Plasma Cleaning After O 2 Plasma Cleaning