Advanced Flexible Circuit Materials
As Components For Particle
Detectors and Other Applications
Neutrinos and Arms Control Workshop
February 5-7, 2004, University of Hawaii
Mark Richmond, Development Engineer
3M Corporate Research Laboratory
© 2003 IEEE. Reprinted, with permission, from:
Robert Dodsworth, Marketing Manager
John Geissinger, Applications Engineer
3M Electronic Solutions Division
Austin, Texas
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Flexible Circuit Products
Product Applications
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and Bio-Medical
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Flexible Circuit Global Support
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3MTM FLEXIBLE CIRCUITS
Global Manufacturing/Lab Locations
COLUMBIA, MO, USA
MFG/LAB
Typical Web Processing
Equipment
KIMITSU, JAPAN (JICS)
MFG/LAB
Advanced Development
Laboratory, Austin TX
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SINGAPORE
MFG/LAB
3MTM Flexible Circuit Demo Circuit
Key Construction Features Applicable To Particle
Detection in Photomultipliers
Open Vias - Metallized or
bare chem milled (40 um) or
laser drilledTo 25 um Dia
•Thin Dielectric
•Roll to Roll Processing
•Wide web process, 12”
expose area
Metal Features
Unsupported To 40 um
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Metal Features
On Dielectric To 20 um
Basic Construction of Typical Two
Metal Layer, Adhesiveless flex
Chemically Milled Via similar
to a GEMS substrate
Base Metal, can be Cu or
Au, .5-70 um in thickness
Dielectric, can be Kapton®,
Apical® or Liquid Crystal
Polymer (LCP)
~25-50um
Cover metals, Ni/Au or Sn
typical in electronic
applications, other options
available.
Cover coat, available in
either Photo Imageable or
Screen Printable
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Advantages of Adhesiveless 3MTM Flexible Circuits
•
Adhesiveless Construction Produced By Direct Metallization of Dielectric
Yielding Uniform Product Construction
•
Monolithic PI (No PI Adhesion Layers)
–
Result  Less Potential Outgassing Of Organic, Redepositable Materials
(Conductive Surfaces Will Not Develop Insulated Regions)
–
Simple Baking or Vacuum Holds Remove Moisture From PI
(Maintain High Voltage Gradient Across Dielectric Large Area Dielectric Layer)
•
Stable Adhesion Between Copper & Substrate (Copper to PI & LCP)
•
Photolith Imaging of All Metal and Dielectric Features
•
Roll to roll (continuous) processing.
•
Simultaneous Chemical hole milling in roll to roll format.
–
Dielectric Patterns Closely Registered to Copper Pattern
Minimal Tooling Cost
•
Net End User Benefit 
High Performance Product Design and Reliability,
Especially, for Long Term Use & Next Level Assembly
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Fine Pitch Roadmap
Fine Pitch
50µm pitch
38µm pitch
35µm pitch
30µm pitch
25µm pitch
2001
2003
2003
2005
Development
2005
2007
2007
2009
Preproduction
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1ML
2ML
Mass Production
“Sea of Holes” Open Tool Foil
For R&D Purposes
Active Area 100 mm x 100 mm
Typical Cross Sectional View Of 2 Metal Layer Foil
3M does not warrant that the product represented by these
samples will be offered for commercial sale in the future.
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Digging Into An Open Tool Foil
Construction Detail
Open Tooled Flex
PI Only
Cu/PI/Cu
Cut Away
Views
PI/Cu Bottom
140 um Hex
Grid
70 um Dia Cu
Holes
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Dielectric Film Property Comparison
(chemically etchable)
Kapton®
H
E
Apical®
NP
HP
LCP
400
800
570
900
480
Elastic modulus (kpsi)
77
60
85
40
30
Elongation (%)
35
50
42
40
28
Tensile (kpsi)
0.15
0.08
0.08
0.06
>0.5
Heat shrinkage (%)
30
13
15
14
17
CTE (ppm/deg.C)
>360
>350
>320
>320
200-300
Tg (deg.)
3
2.4
2.2
2
0.04
Moisture uptake (%)
24
9
13
8
4
CHE (ppm/%RH)
40
7
33
7
0
Water permeability
(gm/m2/day)
3.7
3.3
3.3
3.1
3.0
Dielectric constant
13
7
5
5
N/A
Surface Rq (nm)side 1
40
22
5
5
N/A
side 2
_____________________________________________________________________________
Note: The actual measurement values may be slightly different from the list due to variations from film and test.
Kapton is a registered Trademark of E. I. Dupont and Company
Apical is a registered Trademark of Kaneka High-Tech Materials, Inc.
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Open Via Detail
Non-Conductive Via Shape Vs. Material Types
Dielectric Etch Material A
Minimum Thru Diameter = ~40 um
Undercut Is Minimized
Copper Adhesion Maximized
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Dielectric Etch Material B
Minimum Thru Diameter = 70 um
Undercut Is Present
Copper Adhesion Adequate but denting
effected electrical performance
Open Tool Foil Construction
Foil Parts Made To Date & Possible Variations
Characteristics
Copper Layer Thickness - 5 um (0.5 to 70)
Copper Surface Roughness - ~0.15 um
Dielectric Material Thicknesses - 25 & 50 um
70 um diameter on 140 um pitch today
Other hole geometries/spacing could be investigated
Voltage Withstand (Reported) Using 50 um PI - Over 500V.
(Standard chemical mill process with no additional cleaning)
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3M Support For New Device
& Technology Commercialization
3M Has Production Capability for Large Volumes of Uniform Quality
Components Suitable for Applications Such As:
Electronic
Photodetection Planes (such as GEM Devices*)
X-Ray Polarizer For Imaging
High Energy Particle Counting
Mechanical
Acoustic Filters & Windows (Patterning of Thick & Thin Copper)
Fluidic Channels (Dielectric Patterning, Partial Thickness Milling)
Optics
Wavelength Filters
Moiré Patterns
Maximum Size Component Made to Date  250 mm Diameter
Maximum Artwork Size  305 mm X 305 mm
Open Tool Design (150 mm X 150 mm) Design Is Available
(Minimum Quantity 20 Pcs.)
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*Radiation detectors and X-ray imagers using GEM foils are discussed in
the following U.S. patents, which may have foreign counterparts: U.S.
Pat. No. 6,011,265 "Radiation Detector of Very High Performance” and
U.S. Pat. No. 6,198,798 “Planispherical Parallax-Free X-Ray Imager".
These patents are owned by CERN. 3M expresses no opinion as to the
validity, scope, or relevance of these patents.
Conclusion
•3M CRL is interested in developing new technologies for
high potential markets.
•3M Electronic Solutions Divisions has world wide, cutting
edge, high volume, wide web capability.
•3M’s manufacturing techniques (chemical milling and roll
to roll processing) provide many advantages.
•GEM foil “open tool” design is available.
•CRL is interested in exploring all opportunities in the
GEM’s/particle detection space.
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谢谢你。
Thank
Obrigado
Спасибо
Mange takk
You…..
Merci
Gracias
Ringraziarlo
Vielen Dank
Dank u
Questions?
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