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MERIX CORPORATIONYOUR COMPLETE CIRCUIT BOARD SOLUTION

1/20/20101/20/2010

IPC Board Designers MtgIPC Board Designers Mtg

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Agenda

3:30-4:00 Registration, Snacks, Voting4:00-4:30 Merix Presentation

4:30-6:30 Plant Tour

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Table of Contents

Specifications & Drawing Communications (slide 3)

Common Errors (slides 4-12)

Copper Foil & Plating Thickness Requirements (slides 13-17) Balanced Circuitry (slide 18)

Clearance Rings (slide19)

Laser Drill ing (slides 20-23)

Electrical Test: IPC Definitions (slide 24)

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PCB Specification & Drawing Communications

Identify default tolerances on prints.

Need instructions for soldermask edits on prints for tented vias.Encroach or fi ll?

Need to identify soldermask defined pads to avoid accidental

enlargement.

Keep data files separated for different parts. Should not combine printnotes on one print for sister parts if they do not apply.

Send only one set of data files. Customers are often sending in

ODB++ and Gerber files but they differ in content.

Datum points need to be tangible not an arbitrary point outside of theimage.

Identify intentional net-list errors.

Surface finish should be on the print not buried in the spec.

Prefer to have customer supply the array drawings.

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Common Errors

IPC 4552 Specification for ElectrolessNickel/Immersion Gold (ENIG) Plating for

Printed Circuit Boards Merix commonly sees a misinterpretation of theImmersion Gold thickness spec

As written, the gold thickness spec is 0.05um (1.97uin) minimum. No maximum value is specified.

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Common Errors

ENIG Spec (Continued) Paragraph 3.2.2 Immersion Gold ThicknessThe minimum

immersion gold thickness shall be 0.05

m[1.97

in] at foursigma (standard deviation) below the mean; the typical range is0.075 to 0.125m[2.955 to 4.925in].

We see a lot of callouts for a gold thickness spec of 2-5 or 3-5uin based on this paragraph

Statistics reminder: Range = Max Min

Specs of 2-5 or 3-5 uin are nearly impossible to meet andexceed not only the capability of the process but also theverification equipment.

Merix typical process capability for immersion gold is 2 8 uin,which has a range of 6 uin

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Common Errors

ENIG Spec (Continued) Paragraph 3.2.2 Immersion Gold ThicknessThe minimum

immersion gold thickness shall be 0.05

m[1.97

in] at foursigma (standard deviation) below the mean; the typical range is0.075 to 0.125m[2.955 to 4.925in].

We see a lot of callouts for a gold thickness spec of 2-5 or 3-5uin based on this paragraph

Statistics reminder: Range = Max Min

Specs of 2-5 or 3-5 uin are nearly impossible to meet andexceed not only the capability of the process but also theverification equipment.

Merix typical process capability for immersion gold is 2 8 uin,which has a range of 6 uin

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Common Errors

Specifying Plated Conductor Layers Or

How Thick is an Ounce? What is 1 oz copper? A square foot of 1 oz

thick copper will weigh 1 oz.

According to IPC 4562 the nominal equivalentthickness for 1 oz copper 34.3 um (.00135)

1 oz Foil1.35 mils

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Common Errors

Specifying Plated Conductor Layers Or

How Thick is an Ounce? IPC 4562 and 4101 allow purchased foil to be

10% below nominal. This means the 1 oz foil

Merix buys may be as low as 30.9 uin(.00122)

1 oz Foil1.22 mils

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Common Errors

Specifying Plated Conductor Layers Or

How Thick is an Ounce? IPC 6012 allows 1 oz foil in finished board tobe as thin as 24.9 uin (.00098)

1 oz Foil0.98 mils

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Common Errors

What does this have to do with platedconductor layer thickness?

Merix commonly sees plated layer callouts using ozfor thickness

For example

0.5 oz plated with 1.0 oz

1.5 oz finished

No industry standard for converting weight to

thickness for plated layers (1.4, 1.2 or 1.0?) Are the specified values min, nominal, max?

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Common Errors

IPC 6012 to the Rescue

Table 3.8 specified minimum external conductor

thickness after plating based on specified starting foil

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Common Errors

IPC 6012 to the Rescue

Caveats:

Table specifies externalthickness does it apply to platedinner layers?

Assumes copper in hole is also plated on the surface. Thisisnt necessarily compatible with some HDI platingstrategies filled vias, button plate, etc.

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Copper Foil / Plate Thickness

Preferred dimension in inches.

Specify dimension as a minimum or anominal with a tolerance.

Do not use copper weights [oz/in2 org/M2]

There is no industry standard for conversion

of copper weight to thickness.

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Preferred

Foil Thickness Dimension

Spec

Drawing/Stack-up Callout Where Plated OL Plated IL

Finished copper thickness on the

surface layers to be .002 inch

minimum OL 0.002 inch minimum

Final copper thickness 1.9+/- 0.40mil OL 0.0015 to 0.0023 inches

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Confusing

Foil Thickness Dimension

Spec

Drawing/Stack-up Callout Where Plated OL Plated IL

0.5 oz + Plating (2.0 mils thick) OL

0.5 oz copper callout + 1.9 mils

finished thickness in stack-up OL or IL

0.5 oz (.0024" thick after plat ing) OL

1/2 oz plated with 1oz OL

1oz plated up to 2oz, finished

external copper thickness: 2oz OL

Outer layers shall be produced

by

starting with 1/2 oz. copper and

plate up to a nominal finish of 2oz. copper. OL1 oz copper c lad/1 oz copper

plating

OL

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Confusing

Foil Thickness Dimension

Spec

Drawing/Stack-up Callout Where Plated OL Plated IL

1 oz after plating OL

1 oz copper finishedOL and unplatedIL

Copper weight: 1.5 oz finished OL

305g/M2 fin ished.

Unless indicated otherwise. OLElectroplate copper on outer

layers

to 1.5 oz., nominal. OL

0.5 oz (0.0007) copper clad

(1oz. Minimum after p lating)

outer layers OL

1/2 to 1 oz OL

1.5-2 oz. copper after fabrication

on external layers OL

0.5 oz copper foil plated to 1 to

1.5 oz OL

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IPC-6012B, Am. 1

IPC 2221 C D i

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IPC-2221 Coupon Design

Segments A and B

Purpose

Inspect the structural integrity of the platedfeatures in the board. Examples of platedfeatures are component PTH, via holes,

buried vias, blind vias, and microvias. An attribute inspected during structural

integrity inspection is internal annular ring.

IPC 2221 Coupon Design

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IPC-2221 Coupon Design

Segments A and B

Annular ring / registration inspection Inspection done on IPC-2221 coupons. Coupon represent the smallest pad diameter for each layer. Coupon located where the greatest material movement occurs on the

panel.

IPC 2221 Coupon Design

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IPC-2221 Coupon Design

Segments A and B

Plane Layer

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Plane Layer

Smallest Pad Diameter

The smallest pad diameter onplane layers tends to be thermalrelief pads.

The antipad diameter is the same asother locations on the plane layer.

The thermal relief pad diameter isreduced to fit within the antipad withadequate clearance.

The smaller thermal relief paddiameter is used in the couponpattern used for annular ringinspection.

This results in a pad diameter thatexceeds the registration tolerancefor manufacturing.

Product is non-compliant for

annular ring failures on IPC Class 3product.

When this condition is evident,some design have a larger paddiameter for holes connected totraces.

Pad Diameter

0.018"

Pad Diameter

0.024"

AntiPad Diameter

0.033"

Thermal Relief Pad

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Thermal Relief Pad

Tolerance

What is the effecton functionality of

the circuit board forthe following

conditions?

Condition A

Condition B

A

B

Balanced circuitry and/or use

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Isolated circuitry

Thieving applied

Balanced circuitry and/or useof thieving on plated layers

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Minimum 8.0 mil clearance rings for plated layers

The small surface areaof a clearance ring isdifficult to hold goodResist adhesion. 8.0

mils give a good bondarea to with stand anyplating conditions andpossible handlingdamage

Hitachi Dual (UV+CO2) Laser dril ling machine

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Hitachi Dual (UV+CO2) Laser dril ling machine

Model: LUC-2F21E(C)

System Specifications:

UV Laser system

(1) Model : C-10FA(2) Type of laser : LD pumped UV(3) Wavelength : 355 nm(5) Pulse frequency : 25,000 to 70,000 Hz(6) Average Output : 10W at 50KHz

CO2 Laser system(1) Model : Super Pulse 12A(2) Type of laser : CO2 gas laser

(3) Wavelength : 9,400 nm(4) Pulse width : 0.001 to 0.030 msec(5) Pulse frequency : 100 to 6000 Hz (6) Average Output : 200W max.

Hitachi Dual (UV+CO2) Laser drilling machine

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Hitachi Dual (UV+CO2) Laser drilling machine,

Model: LUC-2F21E(C)System Options

Laser power meter (Built into machine)To measure laser output power and pulse energy.Power measurement software and hardware integral to

machine.

Automatic machine setup function1) Automatic machine warm-up, power measurement

and galvano compensation function

2) LOG functiona) Production control data fileb) GCOMP/GCHK data filec) Laser power measurement data file

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Laser in action

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Micro-via design considerations

1. Aspect ratio Depth : Diameter 0.8 : 1

2. Via shape: Bottom dia. > 50% top dia.

3. Glass styles should be limited to finer glasswhen possible 1080, 106, 2113

4. Top dia. from 3.5 mils to 13.5 mils

5. Registration can be assessed by the paneltargets or when needed internal fiducialscan be used.

6. Buried micro-vias should be epoxy filled,copper filled

1-3 micro-viaconnection inone lamination

process!

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Electrical Test

IPC-9252 Vs IPC-9252A

Class III 10 Ohm 9252A Class III 20 Ohm 9252

Concerns that the industry is designing product under the Class IIIcategory but copper lengths within the layout exceed 10 Ohms. By

referee modeling, any net with any point-to-point length of ~20 mayviolate Class III. This is creating a hybrid type of design as requestsare being made to allow the Class II nets to be accepted. Thisrequires double testing and manual programming as CAM softwarehas not adapted to this new scenario. IPC has not addressed onwhat appears to be emerging as Class 2.5.

Indirect Continuity/Isolation Testing by Signature Comparison

Concern on Class III, AABUS. Difficulty for manufactures to revisitcustomers to allow Flying Probe (Capacitive Discharge) on Class IIIproduct. Not addressed in 9252.

Adjacency (for isolation testing)

Concern on Class III, AABUS. Same difficulty as noted above

IPC-9252A Table 4-1

Quick reference table does not address Class 3/A Exceptions forSpace and Military Avionics (IPC-6012B w/Amendment 1)

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Thank YouThank You