ttm optical pcb - phoxtrotoptical pcb technology for in-chassis interconnects – h-v fabricator’s...

Optical PCB Technology for In-Chassis Interconnects – H-V Fabricator’s View

Marika Immonen, Hui Yuan Jan, Long Xiu Zhu,

Shi Xing Hong, Xiao L. Ren, Guoqiu Yan, Laixin Jiang, May Zhou

Advanced Development – Corporate Technology 4th Optical Interconnect in Data Centers

Symposium

ECOC Dusseldorf

September 19, 2016

Session 2: Bringing Technology to Market I

Contents

• TTM Optical PCB technology – Motivation: High speed system and RF PCB Challenges

– On-board Optical Application Scenarios

– TTM Optical PCB Process and Materials

– Waveguide Functional Characteristics

– OE PCB Challenges in Production

• PhoxTrot project – flash of results – Demonstrators: PhoxDem09.01; PhoxDem09.02

– Dual WG layer technology

– Glass OPCB technology

– PhoxDem09.03 in progress

• Summary and Key Takeaways

Proprietary and Confidential 2

TTM PCB Product Spectrum


Multilayer up to 60+

layers

Embedded passives

Heavy copper up to 10

oz.

Over 50 UL approved

laminates

Thickness up to .450“

Panel Size up to 30"x 54"

Thin core dielectrics

Mixed Dielectric (Hybrid)

Constructions

RF and High

Performance Designs

Buried Resistance and

Capacitance

Constrained Core MLB

HDI Microwave

RIGID PCBS

Military and

Aerospace

Certifications

1 - 68 Layers

High Frequency

(RF) Bandwidth

Designs

Buried Metal

Core

Construction

Surface

Mounted

Heatsinks

SPECIALTY FLEX & RIGID-FLEX

Type 2, 3 and 4

(double sided,

multilayer and

rigid-flex)

30+ layers

Dimensions up to

24" x 48“

Acrylic, epoxy and

adhesive-less

polyimide flex

materials

Over 50 rigid

material options

Thickness up .300"

MIL-SPEC & UL

Qualified

Custom Surface

Finishes Available

Up to 12L "anylayer"

stacked uVia Structure

1.6 / 2.0 mil line /

space

Wide material and

surface finish

selections

14 mil, 6L ultra thin

structure

3/7 mil uVia / Pad size

0.4 mm pitch BGA

with 2 traces fanout

Embedded, distributed

and discrete passive

components

HDI (HIGH DENSITY)

High frequency /

bandwidth

designs

Planar and

screened

resistors

Dimensions up to

24" x 48“

Mixed dielectrics

(hybrids)

Dielectric foam

Conductive paste

Plated cavities

Formed

(conformal) PCBs

Optical machining

RF / MICROWAVE

2,4,6 Layers

(2+2+2

stacked via)

BT material

Wire bonding

(ENEPIG,

Soft gold,

Hard gold)

IC PACKAGES

High Speed PCB Loss Reduction Requirements


COMPUTING AND COMMUNICATIONS – SYSTEMS PCB’S : Conventional, backplane, power, system rigid-flex/flex

RF PCB’s : antenna, base station power amplifier, microwave

Development for On-board Interconnections: Application Scenarios and Solution Space


DEFINITIONS

LR = Long reach 1m/ 39”

MR = Medium reach 50cm/ 20”

SR = Short reach 20cm/ 8”

VSR = Very short reach 10-15cm/ 4”-6”

XSR = Extra short reach ≤ 5cm

USR = Ultra short reach ≤ 1cm

Image source: OIF CEI56G

Glass interposer for optical IC

IBM 2013

Polymer WG on carrier

Flexible PWG links C2C

Flexible PWG links C2M

Fiber flex plane backplanes

Sumitomo

Molex

TTM Optical/Electrical Circuit Board Technology

Company Confidential 6

Hybrid PCB w/ optical and copper signal layers

Copper for power distribution and low speed

Optical layers for high speed signals

Embedded WGs, rigid/flex or flex OE PCBs

Multimode

waveguides

High density arrays Splitters, combiners

and NxN couplers

Low radius bendings,

crossings

Fan in/out structures and Connectors

Out-of-plane turns and vertical routings Optical connector

interface

Low-Loss Optical Materials and Process Optical Waveguide Components and Layer Integration

Channel termination

Pluggable optical connectors

Passive optical alignment

Density over fiber connections

Waveguides

Passive components

High density routings

Waveguide and OE PCB Fabrication Flow


Optical layer steps

Electrical layering steps

Electrical

Electrical

Optical

Substrate or sub-

core

CLAD2

Deposition and

patterning of core

Deposition and

patterning of clad

Lamination with copper layers

and finalization of O/E PCB

CLAD1 CORE

Deposition and

patterning of clad

OPTICAL

CLAD2 CLAD1 CORE

ELECTRICAL OPTICAL ELECTRICAL

TTM MM optical layer fab process utilize existing infrastructure: No need of specialized equipment

TTM Polymer Waveguides on PCB


OPCB fabrication in 16”x20” production panel : Panel scale fabrication capability

After clad1 layering (coating, soft bake, flood exposure, PEB)

After waveguide core patterning (coating, softbake, imaging, PEB,

development)

Product Example: 20L + 1 Opt Embedded


RoC:

0.5…50m

m L1…. mm

L2…. mm

90Bend

18x

• Product with optical layers

• 20 electrical layers with 1 optical layer

• Dimension (WxH): 277 x 312 mm (10”x12”)

• Material: EMC EM-285 HF

• Thickness: 2.8mm (+/- 0.300)mm

• QUALIFICATION

• Process qualifications: drilling (via optical layer, high dense via

arrays), plating, peel strong in customer existing product

• Reflow 4x 260̊ C; Thermal shock: solder float

• Optical layer

• Optical layers b/w L10/11

• Core: 50µm, 250µm pitch

• Optical patterns: straight,

diagonal, 90 bends

MM-PWG Functional Chacteristics (λ= 850nm) INSERTION LOSS

IL: < 0.05 dB/cm at 850nm (MMF)

TL: 0.03-0.05 dB/cm at 850nm (MMF)

TL: 0.4 dB/cm at 1310nm (MMF)

CROSSING LOSS

< 0.057 dB/X (MMF) 90

< 0.046 dB/X (SMF) 90

< 0.17 dB/X (MMF) 45

< 0.17 dB/X (SMF) 45

Light

BEND LOSS

RoC 5mm < 1.9 dB (MMF) < 1.2dB (SMF)

RoC 10mm < 1 dB (MMF) < 1.2 dB (SMF)

CROSSTALK

Waveguide length =20cm (8”)

L/S 50/200µm

Spacing 200µm (8mil) aggressor

Crosstalk isolation: -32 dB

Results – Reliability Tests: Solder Reflow (Tpeak=260°C,

5x), Temp/Humidity (85%RH/85°C), T/C (-40°C/+125°C)

SOLDER REFLOW

Temperature humidity

Test condition:

85%RH/85C

2000 hours

Sample:

Waveguides on silicon

substrate

Results:

No measureable (< 10-5

dB/cm*h) change in

attenuation

Thermal cycles

Test condition:

-40C/+125C

500 cycles

Sample:

Waveguides on

silicon substrate

Results:

No measureable

change in

attenuation

(± 0.005dB/cm)

TEMPERATURE HUMIDITY THERMAL CYCLING

Solder reflow

Test condition:

260C in air

5 cycles

Sample:

Waveguides on silicon

substrate

Results:

Increase of 0.016 ±

0.005 dB/cm (pass

telcordia requirements)

2.4Tbps Waveguide Demonstrator with 25Gbps Embedded Optical Links


• Two OBTs in the link prototype. Launching to WGs via fiber jumpers

• Electrical I/O we use 6 MXP connectors (Huber-Suhner)

• The OBTs are controlled through the I2C interface

Connector for power supply

OBT

OBT

Interface to

waveguides

USB Interface RF I/O

Power supply test Embedded

waveguide links 8x 12 WG ch sets/

board

Total: 96 ch/board

Capacity: 2.4Tbps

• Board: 284 x 311 mm.

• Construction: 6L+1Optical

• No # of WGs: 96 ch (8 x 12 ch)/ board

M.Immonen, R.Zhang, M.Press, H.Tang, W. Lei, J.Wu, H. J.Yan , L.X.Zhu, M.Serbay, “End-to-end Optical 25Gb/s Link

Demonstrator with Embedded Waveguides, 90°Out-of-Plane Connector and On-board Optical Transceivers”

JOINT DEVELOPMENT

Th.2.P2.SC4.13

M.Immonen, R.Zhang, M.Press, H.Tang, W. Lei, J.Wu, H. J.Yan , L.X.Zhu, M.Serbay, “End-to-end Optical 25Gb/s Link

Demonstrator with Embedded Waveguides, 90°Out-of-Plane Connector and On-board Optical Transceivers”

Results – Link Traffic Measurements at 25Gbps


Th.2.P2.SC4.13

PhoxTrot – EU FP7 FHG-IZM, Seagate, Compass

Networks, Mellanox with partners [10.2014-09.2016]


PhoxTroT is a large-scale European research effort focusing on

optical interconnects across the different hierarchy levels in Data

Center and High-Performance Computing Systems:

on-board,

board-to-board and

rack-to-rack

http://www.phoxtrot.eu

Fraunhofer IZM (DE)

Fraunhofer HHI (DE)

Vertilas GmbH (DE)

Seagate Technology Ltd (UK)

ams AG (AT)

TTM Technologies (HK)

AMO GmbH (DE)

ICCS/NTUA (EL)

DAS Photonics SL (ES)

Phoenix BV (NL)

CERTH (EL)

Compass Networks (IL)

Bright Photonics BV (NL)

CTI (EL)

CNRS-UB (FR)

CNRS-LPN (FR)

KIT (DE)

SDU (DK)

UPVLC (ES)

IMEC (BE)

Mellanox (IL)

TTM is developing: polymer waveguide PCBs and interface solutions

http://www.phoxtrot.eu/

Storage Controller Card Emulator with Embedded Optical Layer


PhoxTrot Demonstrator [PhoxDem09.01]

M. Immonen, J.Wu, H. J. Yan, L. X. Zhu, P.Chen, T.Rapala-Virtanen, “Development of electro-

optical PCBs with embedded waveguides for data center and high performance computing

applications”, Proc. of SPIE 8991, Optical Interconnects XIV, 899113. 8 Mar, 2014.

Electro-Optical Router with Optical Waveguide Connectivity


PhoxDem09.02 Physical Specifications

Board outline: 190 mm x 420 mm

Stack-up: 16L +1Opt (b/w L8 and L9)

14+14 embedded TX-RX channels @ 8Gbp/s -> 112 Gbps via board embedded polymer WGs

Max capacity: 1.34Tbps with 168 I/O’s; or 4.2 Tbps @ 25 Gbps/ch

Two CEOS ASICs with on-chip optical interconnects

52×52mm BGA with 4000 electrical pins

a router traffic manager incl. a switch fabric, queuing manager and egress processing. PhoxDem09.02 scaled down of functions of router chips e.g., not running L3 and switch fabric logic

C2C link: 15cm length. Density: 4ch/mm with 250µm pitch

Capacity: 16ch/mm 62.5µm pitch

2x12-ch mid-board MTP connectors (PhoxPlug02)

90 chip-on-board (3.6x0.5x0.2mm)

12-ch lensed MT (TE)

The power budget ~ 8-10dB

Waveguides Waveguides

Fibre-to-Board connector sockets

Chip-to-board optical connector

• Two router chips communicating via 2×14 WG arrays

• Two MTP connectors communicating with router chip via 2×12 WG arrays

• PCB: 16 layers, optical layer embedded into the board stack

HLC OE PCB : 16L + 1Opt (Embedded)

• First complex HLC EOPCB with embedded MM polymer waveguide layer

• Besides optical waveguides, the board contains all required electrical layers and via structures (PTHs, n-PTH, stacked and buried microvias) built around optical cores

Proprietary and Confidential

Fabricated 16L + 1Opt unit - Top side

2.03 mm +/- 0.2mm

Cross-section

Assembled [PhoxDem09.02] Demonstrator Showcased at OFC 2016 (Anaheim 03’2016)


Compass Networks finished assembly of two CEOS ASICs (OE- router chips) and MTP fiber

connector on TTM 16L+1Opt OPCB (Nov/2015)

Two CEOS ASICs with on-chip optical interconnects.

52×52mm BGA with 4000 electrical pins

a router traffic manager incl. a switch fabric, queuing

manager and egress processing.

PhoxDem09.02 scaled down of functions of router

chips e.g., not running L3 and switch fabric logic

Development of multilayer (dual-layer) OPCBs


a b c e

f g h i

MM Dual-WG OPCB development

First dual-layer units complete

Varying core sizes: width 20’ 35’ 50’ 60 µmx height 45-90µm

Excellent layer-to-layer registration < +/-5µm

2L OPCB fabrication in 16”x20” production panel

PhoxTrot09.03 / HDP Joint Eco-System Demonstrator Complete demonstrator platform including chassis and cards

OE2.LC1 - Logic card

(not shown)

OE2.TD1 - Test daughtercard

OE2 - OE2.BP1 - backplane

(HDPuG)

OE2.MC1 - Mezzanine card

with Ultracomm engine and high speed

RF connectors

Features 1. Electro-optical backplane with embedded waveguides (OE2.BP1) 2. Separate, interchangeable flexible waveguides with optical ferrule terminations 3. Backplane connector receptacles (commercial and proprietary) 4. Out-of-plane coupling elements for MPO cables 5. Pluggable Test Daughtercard with embedded waveguides and out-of-plane MPO couplers (OE2.TD1) 6. Pluggable Mezzanine Card to house optical engine and high speed RF connectors 7. Optical fibre or waveguide connection between optical engine and backplane connector plug

TTM Proprietary and Confidential 20

JOINT EFFORT with HDP Optical Interconnect Phase 2

http://www.flextronics.com/

http://www.philips.fi/index.page

PhoxDem09.03 Demonstrator Technologies


Huber Suhner

MXP array

connectors

FCI OBT

optical engine

Polymer WG Backplane

(PhoxDem09.03.BP3)

Glass WG Backplane

(PhoxDem09.03.BP2)

Polymer WG Daughter Card

(PhoxDem09.03.TD1B) Mezzanine Card

(PhoxDem09.03.MC2A)

Polymer WG Flex BP

PhoxTrot Optical Fiber-to-PCB waveguide interfaces


PhoxPlug05 with 90° MLA

assembled in PhoxTest05.03 board

PhoxPlug04 - Multimode waveguide

out-of-plane coupling interface (narrow)


out-of-plane coupling interface (wide)


In-plane coupling interface (narrow)

TTM FHG Glass Optical PCB Technology Core Technology Development [Q1/2016-Q4/2016]


Glass OE PCB

Polymer WG tech, optics integration, connectors

Glass WG PCBs (MM-Glass, SM-Glass) for 1310nm, 1550nm

PhoxDem09.03.BP2 – Backplane w/ Glass WGs


Glass waveguides

FTG0208-02A DMC PN:021457A

Characterization: Cross-section of WGs with white light illumination (as built)


Core w1 Core w2

ch1 ch2 ch3...

Measurement data from FHG

IZM for as-built WGs

• Gradient-index glass waveguides – Wavelength range is 850…1550nm

– Low dispersion (graded index)

– Direct seamless access to external fiber networks

– Mechanical and thermal stable during PCB embedding

– Manufacturing on panel formats

– Glass is substrate material (direct die attachment)

Flexible Polymer Waveguides


Photonic Packages and Single Mode Waveguide OPCBs for Silicon Photonics • Motivation: Emerging packages with silicon photonics chip

and optical transcever co-packaged with ASIC. – Strategic direction by various companies

– Optical IO with fibers or waveguides off package

– Intra package (/interposer or carrier) links with optical waveguide


1. Polymer WGs on carrier 2. Polymer WGs on-module

IBM 2013 IBM 2015

3. Polymer WG ”fly over” flexes off-pkg and C2C

Summary and Key Take Away

• TTM Optical Electrical PCB today

– TTM has panel scale WG fab process to support standard form factors in production environment – low cost, high volume, existing infrastructure

– TTM has technology on polymer waveguide, glass waveguides, flexible WGs

– TRL level and maturity varies per optical technology & eco-system

– TTM OPCBs with MM waveguides show low loss WGs < 0.05 dB/cm and ability to produce complex WG structures: Bends, over-crossings, cascades

– Optical polymer materials with shown compliance in HLC product (chemistries, drilling, plating) and reliability (reflow, thermal cycling)

– Connectors with various partners. Focus on scaling number of channels t and connector assembly routines

• Future steps

– Single mode waveguide technology on package & board level

– Single mode connectors with new set of challenges: novel solutions required (self aligning structures,..)

– Chip-to-WG interface connectors/interface needs more solutions



Acknowledgements: TTM Technologies

X.H. Shi, X.L. Ren, G. Yan, L. Jiang, M. Zhou, R.S. Zhi, L. Liu

Dow Corning Corp.

K. Weidner, J. deGroot, B. Swatowski, M. Mohamed

Financial support from European Commission through FP7-ICT project PhoxTroT

under Contract 318240

http://www.phoxtrot.eu/

Please visit us at Booth #350

ttm optical pcb - phoxtrotoptical pcb technology for in-chassis interconnects – h-v fabricator’s...

Documents