taiwan union technology corporation - ibm · the desired low loss property and compatible with fr-4...

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Signal Integrity

2

Factors influencing Signal Integrity

3

Studying Factors

Studied the following factors

Resin system

Fabric

Construction

Conductor

Moisture

Temperature

Test method

Confidential & Proprietary

4

Resin systems

5

Neat resin electrical performance

Source : IPC EXPO 2009

Resin systems

6

Df (Resin System & RC)

RC

75%

0.004

0.006

0.008

0.010

0.012

0.014

0.016

0.018

0.020

35% 45% 55% 65%

Df

A

B

C

D

E

F

G

H

I

J

Mid-loss G : TUC mid-loss material

H : anhydride base mid-loss system

I : BT/Epoxy base system

Low-loss J : TUC low loss material

A : bisphenol A novolac system

B : bisphenol A+phenol novolac

C : TUC mid-Tg material

D : TUC Hi-Tg material

E : Hi-Tg Dicy-cured system

F : phenol novolac system

FR4


7

Mid / Low Loss Materials

-12

-11

-10

-9

-8

-7

-6

-5

-4

-3

-2

-1

0

0 5 10 15 20 25

Frequency ( GHz )

Lo

ss (

dB

)

Anhydride

Novolac : TU-862 HF Dicy Hi-Tg

Low-loss : TU-872 LK

Trace Length : 4 inch


• Low Dk resin system could be formulated with modified epoxy to achieve

the desired low loss property and compatible with FR-4 processing

parameters

8

Construction

9

1MHz : LCR meter

Dk – Construction

10

1MHz : LCR meter

Df – Construction

11

Loss – Construction

• Construction is one of key factor for loss

Construction Impact

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

0 5 10 15 20 Frequency ( GHz )

Lo

ss (

-d

B/c

m )

HRC LRC

HRC LRC

2 mil 5 mil

Delta dB 8 inch 12 inch 16 inch

5 GHz 0.164 0.246 0.329

10 GHz 0.341 0.512 0.683

15 GHz 0.518 0.777 1.036

20 GHz 0.697 1.045 1.394

Delta dB 8 inch 12 inch 16 inch

5 GHz 0.078 0.116 0.155

10 GHz 0.170 0.254 0.339

15 GHz 0.261 0.391 0.522

20 GHz 0.355 0.532 0.709

12

Fabric

13

Fabric

Source : IPC EXPO 2009

Low Dk Glass Signal Integrity Comparison

GF R/C DK DF

SLK E glass

106 6Z7B 70.6 3.5190 0.0086

1080 6Z5B 64.8 3.7070 0.0083

3313 6ZDB 56.5 3.9400 0.0086

2113 6ZMB 58.5 3.8530 0.0090

2116 6Z3B 54.7 3.9660 0.0086

SLK SP Low Dk

glass 1

1080 6D6B 66.3 3.3830 0.0082

1080 6D6B 63.0 3.3900 0.0074

2116 6D4B 56.6 3.5400 0.0081

SLK SP Low Dk

glass 2

1080 6DbB 67.0 3.3700 0.0085

1086 6DPB 63.8 3.3810 0.0083

3313 6DeB 62.0 3.4600 0.0085

2116 6DdB 59.0 3.5000 0.0084 Confidential & Proprietary

Low Dk Glass Signal Integrity Comparison

• The Dk of CCL reduces approximately by 0.30 -0.45

(depends on the RC) and 0.001 on Df when E glass

replaces with low Dk glass on the same resin system


16

Resin rich Resin poor

Resin Dk ~ 3.2 Glass Dk ~ 5.6

Signal Skew – Differential circuit

Special Layout and Routing

Designer Rotates Image

Lopsided glass weaving


17

1080 FABRIC

Signal Skew – Fabric Selection

Special Layout and Routing

Designer Rotates Image

Lopsided glass weaving


18

Regular Open-Filament Flatten Weaving

1080 Grade Fabric



19

Window Area

Ratio

Regular

Type

Open-filament

Type

Flatten Weaving

Type

2 mil ~30 % ~15 % ~1 %

3 mil ~25 % ~8 % ~3 %

4 mil ~10 % ~3 % ~1 %


100%

• Optimize fabric can moderate the signal

skew effect through:

• Use Low DK fabric

• Increase weaving density

• Even/flatten glass count/weave


20

Conductor

21

HTE – roughened foil RSTF – smooth foil

Conduct Loss – Roughness


22

F

G

Circuit trace surface roughness level

Type Position sample N

HTE Foil F : Shinny side 14 0.115 mil

G : matte side 14 0.313 mil

RTF Foil F : Shinny side 14 0.192 mil

G : matte side 14 0.207 mil

Roughness



23

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 5 10 15 20

Frequency ( GHz )

Lo

ss (

-d

B/c

m )

Smooth Foil

Roughened Foil


Freq/(delta) 8 inch 12 inch 16 inch

5 GHz 0.253 dB 0.379 dB 0.506 dB

10 GHz 0.504 dB 0.756 dB 1.008 dB

15 GHz 0.753 dB 1.130 dB 1.507 dB

20 GHz 1.004 dB 1.506 dB 2.008 dB

Material : Low Loss Material


• The difference in loss increases with increasing in frequency

24

Effective Dk/Df (IBM SPP Method)

Effective Df

0.000

0.004

0.008

0.012

0.016

0.020

0 5 10 15 20 Frequency ( GHz )

Df

HTE Foil

MLS Foil

2D field solver


• Changing from HTE to MLS foil, Df could reduce by ~ 18%

25

Temperature

26

Influence of Temp.

PN cured High Tg FR4

SPP method


• Temp increases from ambient temperature to 70C could cause Df

deteriorate by ~20%

27

Moisture

28

Influence of Moisture

• Resin system is a major factor for moisture pick up


29


Moisture Pick Up (wt%)


30

Moisture Pick Up (wt%)



31

Oxide Treatment

32

Influence of Oxide Treatment

Source : 2009 IPC APEX / Cisco / S20_02

HVLP

VLP

STD

• The oxide tooth also will affect the SI. Shorter the tooth,

lower the interference

33

Measuring Method

34

SECTION 2.5 - ELECTRICAL TEST METHODS

2.5.5A Dielectric Constant of Printed Wiring Materials--7/75

2.5.5.1BPermittivity (Dielectric Constant) and Loss Tangent (Dissipation Factor) of Insulating Material at 1MHz

(Contacting Electrode Systems)--5/86

2.5.5.2A Dielectric Constant and Dissipation Factor of Printed Wiring Board Material--Clip Method--12/87

2.5.5.3CPermittivity (Dielectric Constant) and Loss Tangent (Dissipation Factor) of Materials (Tw o Fluid Cell

Method)--12/87

2.5.5.4 Dielectric Constant and Dissipation Factor of Printed Wiring Board Material--Micrometer Method--10/85

2.5.5.5CStripline Test for Permittivity and Loss Tangent (Dielectric Constant and Dissipation Factor) at X-Band--

3/98

2.5.5.5.1 Stripline Test for Complex Relative Permittivity of Circuit Board Materials to 14 GHZ--3/98

2.5.5.6 Non-Destructive Full Sheet Resonance Test for Permittivity of Clad Laminates--5/89

2.5.5.7 Characteristic Impedance and Time Delay of Lines on Printed Boards by TDR--11/92

2.5.5.8 Low Frequency Dielectric Constant and Loss Tangent, Polymer Films--7/95

2.5.5.9 Permittivity and Loss Tangent, Parallel Plate, 1MHz to 1.5 GHz--11/98

2.5.5.10 High Frequency Testing to Determine Permittivity and Loss Tangent of Embedded Passive Materials

2.5.5.11 Propagation Delay of Lines on Printed Boards by TDR

2.5.5.12 Test Methods to Determine the Amount of Signal Loss on Printed Boards (PBs)

2.5.5.13 Relative Permittivity and Loss Tangent Using a Split-Cylinder Resonator

IPC Dk/Df & SI Test Method

V

V

V

V

V

35

TUC Capability

For base CCL material

2.5.5.2 (Network Analyzer )

2.5.5.9 ( Impendence Analyzer )

2.5.5.13 ( VNA & Split Post Cavity )

For print circuit board

Time delay - 2.5.5.11 ( TDR )

SPP, SET2DIL – 2.5.5.12 ( TDR, VNA )

Cisco MST ( VNA )

Eye-Diagram

TUC Capability


36

Test equipment : HP E4980A

Frequency range : 20KHz~2MHz

From Cp=E0XErX(A/d) to estimated Dk value of material at low

frequency .

D show material Dissipation factor values.

E0= 8.854X10^-12 F/M

Er= the Dk of material

d: thickness

A: Area

IPC 2.5.5.2


37

Equipment Used:

HP4291B 1MHz-1.8GHz RF Impedance / Material Analyzer

HP4291B Test Station

HP16453B Dielectric Material Test Fixture

This method uses the material capacitance and conductance

to determine the Dielectric Constant and Dissipation Factor

IPC 2.5.5.9


38

For resonant measurements, the Dielectric Constant is

determined from measurements of the resonance

frequency and quality factor

The Q=f0/f, where ‘f0’ is the resonance frequency and ‘∆f’ is the

frequency difference between 3dB points

Equipment used : Vector Network Analizar R&S ZVB 20

VNA available frequency range : 10MHz~20GHz

Fixtures working frequency : Split Post Cavity

@1.0GHz @3.0GHz @5.0GHz @10GHz

VNA SPC Fixture

IPC 2.5.5.13


39

Measurement

Equipment Methods

Sample Frequency

Range

Accuracy

Thickness Size Dk Df

Agilent

HP 4291B IPC 2.5.5.9

0.5-1.6

Mm

25x50

mm 1MHZ-1GHz

+/-

0.1

+/-

0.01

Agilent

E4980A LCR IPC 2.5.5.2

0.1~1.6

Mm

50X50

mm

20KHz~ 2MHz +/-

0.1

+/-

0.01

R&S VNA

ZVB 20

IPC 2.5.5.13

SPC

0.2~0.5

mm

80X100

mm

1GHz ; 3GHz

5GHz ; 10GHz

+/-

0.05

+/-

0.005

Summary


40

Insertion Loss Measurement

41

IBM SPP Technique

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

0 2 4 6 8 10 12 14

LOSS

Measured Simulation

Effective Dk/Df up to 50GHz

2D field solver TDR Base

Time-Domain Extraction Technique

SPP output : S21, Dk, Df, R, L, G, C


42

Effective Dk/Df - including

Dielectric Dk & Df

Trace effect

Oxide treatment

Foil roughness

Skin effect PCB

CCL

+

IBM SPP Technique


43

Cisco MST Method

Cisco MST Method : For 2+ GHz range

Use VNA to extract parameters.

“Real PCB” stripline TV – Not a tuned resonator.

Calibration structures built into the board ( TRL )

Thousands of discrete measurements (~5MHz intervals)

Results yielded : Effectively continues Dk/Df curves

Dk/Df extraction algorithms updated to account for Cu

roughness

Source : Cisco

44

Source : Cisco

Cisco MST Method

45

Intel : SET2DIL

SET2DIL

Single-Ended TDR/TDT To Differential Insertion Loss

Use TDR to measure SDD21 instead of VNA.

Measuring SDD21 using only a 2-port TDR

measurement.

More suitable for High-Volume Manufacturing (HVM).

SET2DIL is ½ the length of a standard insertion loss test

structure.

Can also be used as an impedance test coupon.

46

Intel : SET2DIL

Source : 2010 DesignCon / Intel

SET2DIL output : SDD21

47

Measurement results

• Measurement results vary with test method


Material

Type Resin RC %

SPC SPP

Dk Df Dk Df Insertion loss

(-db/inch)

@4 GHz @8 GHz @4 GHz @8 GHz @4 GHz @8 GHz @4 GHz @8 GHz @4 GHz @8 GHz

TU-862

HF

Rich 70 3.84 4.37 0.0141 0.0150 3.90 3.87 0.0187 0.0191 0.682 1.168

Poor 50 4.41 3.81 0.0174 0.0182 4.38 4.34 0.0168 0.0173 0.623 1.097

TU-872

LK

Rich 70 3.37 3.35 0.0087 0.0089 3.52 3.50 0.0126 0.0131 0.529 0.892

Poor 50 3.89 3.87 0.0081 0.0084 3.90 3.88 0.0110 0.0115 0.481 0.811

SET2DIL

Material Df @ 1GHz Foil Layer 4GHz 8GHz

(dB/inch) (dB/inch)

TU-862 HF 0.01

HTE L3 -0.581 -0.967

TU-862 HF HTE L6 -0.579 -0.965

TU-872 LK 0.008

MLS L3 -0.401 -0.793

TU-872 LK MLS L6 -0.398 -0.789

48

Loss Dominants

49

Attenuation = f ( frequency )

= Dielectric loss + Conductor loss

= Loss ( base material ) + Loss ( circuit trace )

= Material Dk / Df + Circuit Geometry and Roughness

Loss Elements (SPP Method)


50

Loss Dominator

~1.5GHz

Overall Loss

Conduct Loss

Dielectric Loss

FR4

Breakdown element

RTF foil


51

~4.0GHz

Loss Dominator

Overall Loss

Conduct Loss

Dielectric Loss

Mid-Loss

RTF foil


52

Loss Dominator

Overall - HTE

Overall - RTF

conductor - HTE

conductor - RTF

Dielectric

~12GHz

~17GHz


53

Loss Elements (SPP Method)


• Before the breakeven point (circle with red), the conductor will carry more

weight age in total loss than material. After cross over the breakeven point,

material will have higher effect on the total loss than conductor

• Break even point will be shifted to the right when moving from standard loss

to very low loss material

• Before the breakeven point, improvement should focus on improving the

processes like oxide type, copper tooth or copper etch rate. However, after

the breakeven point, the total loss can be reduced effectively through

selecting a lower loss property material

• Copper becomes a critical factor when moving toward from standard loss

application to very low loss application

54

Product Copper

Construction

Oxide

Moisture Temp.

Test Method

Fabric

Signal

Integrity

Factors influencing Signal Integrity


taiwan union technology corporation - ibm · the desired low loss property and compatible with fr-4...

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