Liquid Crystal Polymer Substrates to Enable Advanced RF and Medical Applications

Transcription

1 Liquid Crystal Polymer Substrates to Enable Advanced RF and Medical Applications Susan Bagen & Brian Sinclair MST Inc. Eckardt Bihler, Marc Hauer & Daniel Schulze DYCONEX AG New England 42nd Symposium & Expo

2 Attenuation db LCP LIQUID CRYSTAL POLYMER - PROPERTIES Very flexible thermoplastic 5 SIGNAL ATTENUATION High temperature stability Si** (Tg > 280 C, Td > 320 C) 3.5 Very low water absorption (0.04 %) GaAS** Near-hermetic 2 LCP* Excellent high frequency properties (ε R = 2.9, tan θ = ) 0.5 Light weight (1.4 g/cm 3 ) Frequency GHz 120 *D. Thompson, et al., W-Band Characterization of Finite Ground Coplanar Transmission Lines on Liquid Crystal Polymer (LCP) Substrates, IEEE ECTC ** Fred Brauchler, Ph.D. Dissertation, The University of Michigan, Ann Arbor, MI. New England 42nd Symposium & Expo DYCONEX AG May

3 COMPARISON of MATERIALS Material Property LCP Rogers Ultralam 3000 PTFE / Glass Rogers RT/duroid 5880 Hydrocarbon / Ceramic Rogers RO4350B PTFE / Ceramic Rogers RO3003 LTCC Different Suppliers Dielectric constant Dissipation factor Water GHz * % < 0.1 < 0.05 CTE X ppm/ C * CTE Y ppm/ C * CTE Z ppm/ C * Density g/cm Thermal conductivity W/m K * * Values vary depending on LTCC type used New England 42nd Symposium & Expo DYCONEX AG May

4 PROCESS PROPERTIES LCP vs. LTCC LCP PCB processes produce improved conductor structures with reduced skin effect losses at high frequencies. Edge profile nearperpendicular and better defined. LTCC printed conductor profile LCP Copper etched conductor profile Conductor edge roughness reduced. 65µm traces on LTCC 60µm traces on LCP New England 42nd Symposium & Expo DYCONEX AG May

5 Effective Dielectric Constant LCP FREQUENCY UP TO 110 GHz LCP has stable dielectric constant over a very wide frequency range LCP Frequency (GHz) Multilayer structures have homogeneous LCP dielectric throughout cross-section. Source: IEEE ECTC 2003 W-Band Characterization of Finite Ground Coplanar Transmission Lines on Liquid Crystal Polymer (LCP) Substrates, Dane Thompson*, Pete Kirby, John Papapolymerou, Manos M. Tentzeris, Georgia Institute of Technology New England 42nd Symposium & Expo DYCONEX AG May

6 Dielectric Constant LCP vs. CONVENTIONAL PCB MATERIALS 4.8 Dielectric Constant Variation with Moisture LCP, Polyimide, and FR-4 Laminates FR-4: 50 C Immersion FR-4: 23 C, 50%RH PI: 50 C Immersion PI: 23 C, 50%RH LCP: 50 C Immersion LCP: 23 C, 50%RH Frequency, GHz LCP dielectric constant remains stable upon exposure to moisture. New England 42nd Symposium & Expo DYCONEX AG May

7 Dissipation Factor LCP vs. CONVENTIONAL PCB MATERIALS Dissipation Factor Variation with Moisture LCP, Polyimide, and FR-4 Laminates FR-4: 50 C Immersion FR-4: 23 C, 50%RH PI: 50 C Immersion PI: 23 C, 50%RH LCP: 50 C Immersion LCP: 23 C, 50%RH Frequency, GHz LCP dissipation factor remains stable upon exposure to moisture. New England 42nd Symposium & Expo DYCONEX AG May

8 LCP SUBSTRATE FABRICATION FEATURES Cavity structures for die placement and patch antenna Flexible antennas, connectors & electrodes Source: D.L. Paul, et al., Flexible Dual Band LCP Antenna for RFID Applications, Proceedings of the 2013 International Symposium on Electromagnetic Theory, pp New England 42nd Symposium & Expo DYCONEX AG May

9 LCP SUBSTRATE FABRICATION FEATURES Wirebondable cavity ledge to access inner layers without lossy vias Air bridges New England 42nd Symposium & Expo DYCONEX AG May

10 LCP SUBSTRATE WITH HEATSINK BASE High power density application Direct bonding to heat sink Operating temperature up to 150 C Gold wire bondable surface: ENEPIG Buried RF tracks under lid mounting Lids mounted to circuit to seal cavities Metal Lid 50 µm LCP 50 µm Bondply 100 µm LCP LCP Die Cavity Aluminum Plate New England 42nd Symposium & Expo DYCONEX AG May

11 HF LCP BGA PACKAGE Laser blind vias 50 or 75 µm Laser vias through 3 layers 75 or 100 µm Line / Space: > 25 / 25 µm Lid sealing for near-hermetic package Metal Lid Cavity 50 µm LCP 50 µm Bondply 100 µm LCP 20 µm LCP Soldermask Die BGA New England 42nd Symposium & Expo DYCONEX AG May

12 BIOCOMPATIBLE SUBSTRATES New biocompatible metal layers New market fields Smaller feature sizes Biocompatible PCBs Manufacturing know how Large panel format Long term stability New England 42nd Symposium & Expo DYCONEX AG May

13 COMPARISON: Standard PCB vs. Noble Metal PCB Standard PCB subtractive copper etching Thick metal Line / Space: > 25 µm Reliable z-axes connection (via) Noble metal PCB additive technology Thin metal Line / Space: < 25 µm Challenging z-axes connection Thick Cu Standard PCB Noble Metal PCB Thin Metal high resolution Reliable vias Biocompatible Electrodes Multilayer Flexible thin PCB Typical build up of a sensor New England 42nd Symposium & Expo DYCONEX AG May

14 ISO : Cor 1:2010 Regulation Definition of Biocompatibility: The quality of not having toxic or injurious effects on biological systems. * The ISO : Cor 1: 2010 set a series of standards for evaluating the biocompatibility of a medical device prior to a clinical study. ** 18 different specification points ISO :2009 Biological evaluation of medical devices Part 1: Evaluation and testing in the risk management process ISO :2009 Biological evaluation of medical devices Part 18: Chemical characterization of materials Project Risk "There is no bio-incompatible material.. the dose makes the poison" Wrong constraint too carefully too careless Patient Risk Bio PCB Project New England 42nd Symposium & Expo DYCONEX AG * Dorland's Medical Dictionary ; ** Wikipedia

15 Cytoxiticity Sensitization Irritation or intra cutaneous reaction Systematic Toxiticity Subacute and subchronic toxiticity Genotoxiticity Implantation Hemocompabtibility Chronic toxiticity Carcinogenicity ISO : Cor 1:2010 Biological Evaluation Tests Not all tests are essential but a base knowledge of ISO is mandatory Substrates processed by DYCONEX have been successfully tested for ISO Test for in vitro cytoxicity Nature of Body Contact Category Surface Device External Device Implant Device Medical Device Category Contact Skin Mucosal menbrane Breached surface Blood Path Direct Tissue bones dentin Circulating blood Tissues bones Blood Contact Time A- limited (< 24 h) B- short term (24h - 30 d) C - permanent (> 30 d) Biological Effect A x x x B x x x C x x x A x x x B x x x o o C x x x o x x o o A x x x o B x x x o o o C x x x o x x o o A x x x x x B x x x x o x C x x o x x x o x o A x x x o B x x x x x x x C x x x x x x x o A x x x o B x x x x x x x C x x x x x x x o A x x x o B x x x x x x x C x x x x x x x o A x x x x x x x B x x x x x x x x C x x x x x x x x o x - Test according ISO o - Additional Tests (USA) New England 42nd Symposium & Expo DYCONEX AG May

16 BIOCOMPATIBLE MATERIAL AVAILABLE OPTIONS For flexible applications: Polyimide LCP For rigid applications: Glass PEEK Flexible material with a rigid stiffener Cover materials: For flexible applications: Solder mask (can be used for short term implants) LCP Parylene coatings New England 42nd Symposium & Expo DYCONEX AG May

17 APPLICATION: SHORT TERM BLOOD GLUCOSE SENSORS Compact, handheld, portable device which measures blood glucose levels as part of a diabetes management regimen for the chronic diabetic Direct implantable bio sensor with clinical approved studies flexible PCB substrate flexible cover mask 30 days in human body Measures capacitive electric charge current Typical 3-electrode system Source: _images/5060.jpg Counter Electrode Reference Electrode Work Electrode C Ag/AgCl Au Source: New England 42nd Symposium & Expo DYCONEX AG May

18 APPLICATION: PERMANENT IMPLANT COCHLEAR ELECTRODES Need of pure biocompatible materials without copper for long term implant cover mask Pt Au LCP for excellent biocompatible properties Au for good adhesion and flexible properties LCP Pt for selective electrodes robustness Test design with 125 µm traces on 250 µm pads Test structures with 15 µm Line / Space N =5.62 % C =2.84 % Au = % pure gold electrodes gold + platinum electrodes New England 42nd Symposium & Expo DYCONEX AG May

19 APPLICATION: THERMISTORS FOR HEAT MEASUREMENTS Balloon catheters with electrodes for neurostimulation or ablation Invasive surgical procedure Extremely flexible ultra thin 2-layer LCP build up with 50 µm final thickness One thermistor per electrode couple with thin film layer 25 µm Line / Space One sided copper plating with 100% via-fill Source: Surface finish: electroplated gold on copper for short term implant Source: New England 42nd Symposium & Expo DYCONEX AG May

20 SUMMARY Advanced LCP processing has been developed to establish fabrication capabilities of complex substrates for RF microwave applications as well as structures for directly implantable medical technologies. Examples of RF substrate designs are complex multilayer stackups that include cavity structures for bonding of high power die directly to heat sink materials. Multilayer structures of LCP with noble metal conductors for biocompatible medical implants are also discussed. New England 42nd Symposium & Expo DYCONEX AG May

21 THANK YOU FOR YOUR ATTENTION! DYCONEX AG Grindelstrasse 40 CH-8303 Bassersdorf Switzerland Phone +41 (43) Fax +41 (43) New England 42nd Symposium & Expo DYCONEX AG May