High Frequency Flex Project Definition Phase Project Lead: TBD Project Facilitator: John Davignon,...

High Frequency Flex ProjectDefinition Phase

Project Lead: TBDProject Facilitator: John Davignon, HDPUG

HDP User Group Member Meeting Santa Clara, CA Feb 10-11, 2016

Problem Statement

© 2015 HDP User Group International, Inc. All rights reserved

Flexible printed circuits (FPCs) provide a practical option for interconnection of printed circuit boards and electronic modules. Moreover FPC construction offers greater levels of impedance control compared with co-axial and other wired connections. However with FPCs increasingly being used in high speed digital applications, understanding their electrical performance at high frequencies becomes a growing challenge. Differences between measured results and present models have been seen. Several issues arise from using them for this purpose.

1. Controlling the critical geometries of flexible materials as they differ from rigid PWBs.

2. The differing properties of the materials (Dk, Df etc.) involved and the fact that some dielectrics and adhesives are very hygroscopic.

3. Cross hatch GND planes. Simulating the effect of the non-contiguous plane and the effect of various shapes. Cross hatch GND Planes used for Flexibility & Impedance control

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Project Proposal/Scope

Of the three areas of concern the team has decided to conduct a study to characterize the effect on signal integrity for flexible printed circuit boards operating at high end digital transmission frequencies with regards to:

• Different design features: Various Crosshatched ground plane designs

• Material choice: Polyimide (DuPont/Panasonic)• Laminate thickness: 100 um• Frequency ranges up to 20 Ghz• S parameter performance analysis (Insertion & Return Loss

and Impedance) of FPC test vehicles• Comparison of measured results vs. models

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DOE/Objectives


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• Design a test vehicle using a Solid Plane as the reference feature and various cross hatch designs.

• Run with a series of frequencies up to 20 GHz and see the effect on impedance/loss. Would need TDR and S parameters.

• Evaluate how the cross hatch designs effects impedance and S parameters (insertion and return loss)

• Overlay the response on a plot and evaluate how much they are different or change.

• Compare model to measured results

Deliverables

© 2015 HDP User Group International, Inc. All rights reserved 5

• Publish a comparison of measured SI data to present model predictions

• Publish guidelines on crosshatch design findings

• Publish final report to members• Present finding at industry conference

(EIPC/IPC APEX) • Recommendation for the next phase of work

Benefits


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This project will provide the industry with the fundamental knowledge of the mechanical/design and electrical properties differences between flex and rigid products. Provide important knowledge of why the present models do not match the performance being measured.

Provide better methods to design with flex going forward.

Provide an understanding of the effects of crosshatching design and how to improve the design.

Status


• Team focused on replacing Project Lead and loss of Polar Instruments

• Flex Laminate Materials and thickness have been decided

• Frequency test range has been decided• Coupon designs are underway • Project still open to new participants and presently

seeking project resources• CAD Designer help for coupon/layout (Ciena)• Additional Flex Fabricator• Additional test house (SPP - Introbotix)• 3D simulation capabilities

TV Stack-up


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25 um Low Modulus PI Constant - used for both DuPont and Panasonic builds25 um Acrylic Adhesive

18 um 0.5 oz RA Cu

50 um High Modulus PI Panasonic R-F775 .002"RAH/RAH

18 um 0.5 oz RA Cu

25 um Acrylic Adhesive

50 um Low Modulus PI Constant - used for both DuPotn and Panasonic builds

25 um Acrylic Adhesive

18 um 0.5 oz RA Cu

100 um High Modulus PI Panasonic R-F775 .004"RAH/RAH

18 um 0.5 oz RA Cu

25 um Acrylic Adhesive25 um Low Modulus PI Constant - used for both DuPotn and Panasonic builds

LF0110 Coverlay

AP8525R Core

LF0121 Bondply

AP8545R Core

LF0110 Coverlay

Flow Chart


MaterialsHatched Plane TV Design

Fabricate TV Test

Select Laminate Materials

Procure Materials

PanasonicDuPont

ImpedanceLoss

–DuPont/Introbotix

Design TV w/ Gerber files

M-Flex

Fabricator(s)TTM

DOE Definition

Downselect Objective/Goals

3D Simulations –MFlex

2D Simulations - TBD

Finalize Test coupon designsDuPont/ Ciena

Analyze DataDuPont/Nokia

Write ReportTBD

Present Report Close Project

Resource & Schedule


Task Owner Planned Schedule

Actual Schedule

DOE Definition Polar Q4’ 15 Completed

Design TV coupons Polar Q4’ 15 In-progress

Generate Gerber/Design Files

M-Flex / Ciena Q1’ 16

Procure TV laminate DuPont / Panasonic

Q1’16

Fabricate TV TTM Q2’16

Test - Measure Coupons

DuPont / Introbotix

Q3’16

Analyze Data / Compare Si to Models

DuPont / Nokia-US

Q3’16

Write Report Team Q4’16

Present / Publish Findings

Team Q4’16

Project Participants


DuPont EngentIBMM-Flex –Non-MemberMicroConnex – Non-MemberNokia-USPanasonicRogersTTM

High Frequency Flex


Potential Project Partners

Input is still welcome from HDP User Group members who can contribute. In particular, a CAD designer, additional Flex fabricator and test houses/test equipment providers would be desirable for the project to deliver maximum benefit.

Contact : John Davignon, HDP Project Facilitator at [email protected].

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mailto:[email protected]

High Frequency Flex Project Definition Phase Project Lead: TBD Project Facilitator: John Davignon,...

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