omg fidelity electroless nickel immersion gold omg fidelity electroless nickel immersion gold...

24
OMG Fidelity OMG Fidelity ELECTROLESS NICKEL ELECTROLESS NICKEL IMMERSION GOLD IMMERSION GOLD FIDELITY

Upload: ava-ruddell

Post on 31-Mar-2015

290 views

Category:

Documents


5 download

TRANSCRIPT

Page 1: OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD FIDELITY

OMG FidelityOMG Fidelity

ELECTROLESS NICKELELECTROLESS NICKELIMMERSION GOLDIMMERSION GOLD

FIDELITY

Page 2: OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD FIDELITY

Typical PCB ProcessTypical PCB Process

Acid CleanAcid Clean

MicroetchMicroetch

Palladium ActivatePalladium Activate

Electroless Nickel PlateElectroless Nickel Plate

Immersion Gold PlateImmersion Gold Plate

Page 3: OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD FIDELITY

Metal Finishing Metal Finishing EN FormulationsEN Formulations

Low Phos.Low Phos.

Chosen for solderablity.

Heavy metal stab. Difficult to control. No longer in use

for PCB processing.

Mid Phos.Mid Phos.

Great general purpose plating.

Not designed for PCB processing.

Can skip plate. Still used for PCB

processing.

Page 4: OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD FIDELITY

9026M Electroless Nickel9026M Electroless NickelSpecifically formulated for circuit boardsSpecifically formulated for circuit boards

Consistent deposition rate over a wide Consistent deposition rate over a wide range of bath loading.range of bath loading.

No minimum work load! No Dummy panels!No minimum work load! No Dummy panels! Self pH regulating. Self pH regulating. 1 to 1 replenishment. Easy to control.1 to 1 replenishment. Easy to control. No bail-out, far less to waste treat.No bail-out, far less to waste treat. Works well with many types of Works well with many types of

soldermasks.soldermasks.

Page 5: OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD FIDELITY

Electroless Ni Bath is Electroless Ni Bath is KeyKey to this Process to this Process

Many problems seen in the industry come from the electroless nickel bath.

Two main process problems: Skip and Stray plating along with the main performance problem identified recently ; “Black Pad”

Although other processes can influence these problems, most of the control is in the electroless nickel bath formulation and operation..

Page 6: OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD FIDELITY

Electroless Nickel Bath Electroless Nickel Bath Ingredients Ingredients

NICKEL NICKEL

REDUCING AGENTREDUCING AGENT

COMPLEXERSCOMPLEXERS ADDITIVESADDITIVES

STABILIZERSSTABILIZERS

Page 7: OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD FIDELITY

EN Bath Additives Effect EN Bath Additives Effect on PCB’son PCB’s

Key to Soldermask compatibility.

Controls phosphorus content and deposit characteristics/performance.

Determines operating temperature and plating rate.

Determines work load range. Prevents bath decomposition from

normal activator drag-in.

Page 8: OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD FIDELITY

Type and Control of Type and Control of Additives are Additives are CriticalCritical Control of replenishment is essential to

proper electroless nickel operation as well as the properties of the deposit.

Over stabilized >> Skip (areas without EN)and “black Pad” (areas with EN).

Under stabilized >> Stray (EN creeps on to laminate or soldermask)

Consumption of Additives may not be equal to that of nickel and hypo. This will create an “out of balance” condition.

Page 9: OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD FIDELITY

Effect of Additive BalanceEffect of Additive Balance

For many years, certain compoundsFor many years, certain compounds

(typically two or three types) are used(typically two or three types) are used

as additives in electroless nickelas additives in electroless nickel

formulations at PPM levels. They mustformulations at PPM levels. They must

be in balance to get an optimal nickelbe in balance to get an optimal nickel

deposit. Their balance or “ratio” has adeposit. Their balance or “ratio” has a

large effect on the depositlarge effect on the deposit

characteristics. characteristics.

Page 10: OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD FIDELITY

““Out of Balance”Out of Balance”Deposit effects Deposit effects

Low type 1 additive and/or high type 2• Rough deposits• Tank plate-out• Background plating• Black pad and possibly skip plate

Low type 2 and/or high type 1• Edge pull back• Low plating rate

Page 11: OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD FIDELITY

Additive LevelsAdditive Levels

When the additives are in balance, the deposit may appear normal. Higher than normal levels can cause problems that are not easy to detect.

Assembly defects are usually detected too late.

The goal is to eliminate the root cause of unseen defects rather than try to precisely control the levels.

Page 12: OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD FIDELITY

Real World Processing- Real World Processing- What HappensWhat Happens In Your TankIn Your Tank

NickelLevel

AdditiveLevel

AdditiveWith NiReplen.

AdditiveTotal

100% 100% 0% 100%90% 60% 40% 100%

80% 36% 80% *116%

70% 22% 120% *144%

60% 13% 160% *173%

Continued large replenishments can aggravate these higher than normal levels.

Page 13: OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD FIDELITY

Cyanide Strip TestCyanide Strip Test

Indicates corrosion resistance of the nickel deposit.

Does not show the difference between nickel oxide and bath by-products. Nickel oxide is normal and will not be a problem for assembly as long as the gold is present and of sufficient thickness.

Strip time/temp and stripper bath composition have large effects on the appearance of the nickel.

Page 14: OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD FIDELITY

““Black Pad”?Black Pad”?Hard to tell by eye!Hard to tell by eye!

“A” “H” “M”Photos taken after immersion gold was cyanide stripped.

This shows the boundary layer between the bulk EN and the gold. “H” has a phosphorus content of 12%. “A” and “M” both

have a phosphorus content of 7%, with different stabilizers. High phos nickel (“H”) has the highest corrosion resistance to the stripping solution. Slight darkening from nickel oxide (“M”) should not be confused with unwanted bath compounds.

Only “A” has detectable amount of Additive byproducts.

Page 15: OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD FIDELITY

““Hypercorrosion” =Hypercorrosion” =Much ConfusionMuch Confusion

Immersion Gold bath corrosion has Immersion Gold bath corrosion has been confused with as plated been confused with as plated electroless nickel deposit structure.electroless nickel deposit structure.

Until now, little work has been done Until now, little work has been done on the effects of the EN additives on on the effects of the EN additives on both composition and structure.both composition and structure.

Page 16: OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD FIDELITY

Structure VsStructure Vs Composition Composition

This type of nickel structure has passed all assembly criteria. Only extremely rough

deposits where nickel to nickel failure is likely will cause assembly rejects.

Test sample plated at both higher than

normal pH and temperature

Page 17: OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD FIDELITY

What Is “Black Pad”?What Is “Black Pad”?

Whatever the cause, everyone will agree,

assembly rejects are the major concern.

What is the cause? How can a theory be proven? Analysis of failed parts is a requirement of

any defect investigation. Once a mechanism is suspected, it must be

tested by assembly.

Page 18: OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD FIDELITY

Assembly Performance Assembly Performance TestingTesting

Performed at independent test labPerformed at independent test lab

#1. Circuit patterns prone to “black

pad” are selected for test. #2. Patterns are plated with two

different EN formulas at four

different stabilizer levels. #3. Wire leads are applied. #4. Leads are pull tested to failure.

Page 19: OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD FIDELITY

Performance TestingPerformance TestingAcceptability CriteriaAcceptability Criteria

Pass• Wire breaks, other than at neck• Pad (foil copper) pulls from substrate

Fail • Wire separates from pad• Neck of wire breaks

Page 20: OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD FIDELITY

Assembly Performance Assembly Performance Results- Pull TestResults- Pull Test

0

20

40

60

80

100

50% 100% 150% 200% 250%

EN Bath Additive Concentration (% of Normal)

%Y

ield

aft

er T

est

Typically used additives 9026M Additive System

Page 21: OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD FIDELITY

Solder Joint Solder Joint Shear Test ResultsShear Test Results

0

10

20

30

40

50

60

70

80

90

50% 100% 150% 200% 250%

Additive Level in EN Bath

% F

ail

afte

r 1

Kg

of

shea

rTypical Additive 9026M Additive

Page 22: OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD FIDELITY

9026M Additives9026M AdditivesThe EN System Improved !The EN System Improved !

New Additives for improved circuit New Additives for improved circuit board performance (assembly).board performance (assembly).

Improved system eliminates Improved system eliminates break-down and co-deposition break-down and co-deposition mechanism. No “black pad”.mechanism. No “black pad”.

Page 23: OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD FIDELITY

9026M Deposit9026M DepositShelf Life TestingShelf Life Testing

Average Wetting Forces @ 5 MTO’s

85% RH + 85°F aging

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

0.2

0.25

0.3

0

0.6

1.2

1.8

2.5

3.1

3.7

4.3 5

5.6

6.2

6.8

7.5

8.1

8.7

9.3 10

time in seconds

mN

/mm

control

8 hrs

16 hrs

24 hrs

Page 24: OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD OMG Fidelity ELECTROLESS NICKEL IMMERSION GOLD FIDELITY

SummarySummary

Typical Metal Finishing formulations are not well Typical Metal Finishing formulations are not well suited for Printed Circuits.suited for Printed Circuits.

Although some Additives are in low Although some Additives are in low concentrations (ppm), they have profound concentrations (ppm), they have profound effects on the deposit composition and structure. effects on the deposit composition and structure.

When “black pads” are seen, higher than normal When “black pads” are seen, higher than normal conventional Additive concentrations are usually conventional Additive concentrations are usually the culprit. the culprit.

Even at much higher than normal Even at much higher than normal concentrations, the 9026M Additives will not concentrations, the 9026M Additives will not cause assembly rejects.cause assembly rejects.