ormecon csn immersion tin - intercontifiles.interconti.cz/200000656-55c3b56b53/ormecon-csn.pdf ·...

Whisker Reduced Process & Optimal Solderability

ORMECON CSN

Immersion Tin

A Platform Specialty Products Company. 2

HASL OSP Imm Silver Imm Tin ENIG ENEPIG

Planarity No Yes Yes Yes Yes Yes

Solderjoint Cu-Sn Cu-Sn Cu-Sn Cu-Sn Ni-Sn Ni-Sn

Relative Cost $ $ $$ $$ $$$ $$$

IPC Shelf Life No Specification No Specification 12 months 12 months 12 months 12 months

Reflows 6 4 6 2 6 6

Contact E-Test, ICT Difficult E-Test, ICT, Keypad E-Test E-Test, ICT, Keypad E-Test, ICT, Keypad

Press Fit Good Good Good Good Good Good

Au Wirebond No No No No No Yes

Al Wirebond No No Yes No Yes Yes

Final Finish OverviewAdvantages & Disadvantages


Processability

A Complete Value Chain Solution

Visibility

Manufacturability

Dependability

Reliability

ORMECON CSN Delivers Value Throughout The Supply Chain


High Crystallinity & Reduced Copper Diffusion: lower

internal stress, less oxidation for improved appearance, more

free tin

Effective Whisker Protection: easy controllable whisker reducing additives in the pre-dip

Eliminated Tin Melting Risk: Ag content maintained at sufficiently low levels to prevent tin layer melting

Effective Mousebite Reduction: Optimal process control and replenishment ensures minimal mousebite

Reduction in Surface Discolouration: combination of post-

treatments for contamination removal. Reduced scrap for visual

defects

Lead-Free Solderability: Consistent solderability during

multiple assembly steps

Robust Process, Long Life: Stable plating quality within a wide process window

ORMECON CSN At a Glance


Whisker & Mousebite Reduction

ORMECON CSN

Vertical and horizontal

operations.

MacDermid Enthone technology

in the pre-dip

Lower temperature process

Less soldermask degredation

Robust, long bath life

CLEANER

MICROETCH

PRE-DIP

TIN PLATE

POST-TREATMENT

ORMECON CSN Process


Technology & Reaction Mechanism

ORMECON CSN

Technology of the Ormecon CSN pre-dip controls the copper

oxidation reaction allowing for improved tin layer properties

Cu2+

Sn0Sn2+

Cu0

Cu will deposit on

Sn

Sn will NOT deposit on

Cu

Cu0

Sn2+

Thiourea changes

oxidation potential of

Cu to below Sn

General deposition rule:

The more noble metal will deposit on the less noble metal.

2Cu + Sn²+ ------> Sn + 2Cu+


Product Line

ORMECON CSN

CLEANER

MICROETCH

PRE-DIP

TIN PLATE

POST-TREATMENT

ORMECON CSN ProcessPC 7086

Alkaline for optimized

surface cleaning

Usually Customer Own

For oxide removalOMP 7001 R

Deposition of a wet

Organic Metal / Ag nano

layer. Influences whisker

growth and tin deposition

mechanism.

CSN 7004-1

CSN 7004-2

CSN 7004 R1 V3

CSN 7004 R2 V3

CSN 7004-2 V3

Components for MU &

replenishment

Deposition of a high

crystalline structured tin

layer

RAD 7000 C

Removes polar

compounds. Reduces

ionic contamination

RPT 7000 C

Removes non-polar

compounds. Reduces

surface discolouration


Process Advantages

ORMECON CSN

Competitive Immersion Tin Supplier

Acid

Cleaner Rin

se

Micro Etch Pre-DipImmersion Tin

Sn + Ag (+Cu)Rin

se

DryFinal rinsing section

MacDermid Enthone with Organic Metal Silver Pre-dip

Cleaner

Rin

se

Micro Etch

Rin

se


Pre-Dip

Ag

Immersion Tin

Sn (Cu)

Three metals in one bath very difficult to control, complicated

replenishment

Contain competing immersion reactions (e.g. ImSn and ImAg) which will

yield inconsistent coating composition and plating thickness

Annual new make up required

Ag and Sn separated independent monitoring, easier maintenance &

process control, simple replenishment

A precise quantity of the secondary metal is applied prior to the immersion

tin coating providing the most consistent Ag/Sn ratios pad to pad and board

to board


Stability & Tin (IV)

Robust Process

Sn deposition rate of CSN 7004 is NOT affected by Sn(IV) while the

other ImSn process is strongly affected above 2 g/l of Sn(IV)

The other Sn process requires costly procedures to remove the Sn(IV)

ORMECON CSN

Classic (CSN 7004)

Other MSA ImSn

Tin

th

ick

nes

s [

µm

]


Stability & Tin (IV)

Robust Process

CSN has a higher throughput at higher Sn(IV) concentrations

Throughput Veriation

0%

20%

40%

60%

80%

100%

0 1 2 3 4 5

Sn (IV) Concentration (g/L)

CSN

Other supplier


Three metals in one bath very difficult to control

Ag deposits together with Sn

Too much Ag in Sn layer causes Sn layer to melt during assembly

Subsequent assembly steps become more difficult

Competitive Immersion Tin Supplier

Acid

Cleaner Rin

se

Micro Etch Pre-DipImmersion Tin

Sn + Ag (+Cu)Rin

se


Ag is deposited and controlled separately to the Sn

Amount of Ag deposited significantly less than competitor

A lower Ag content in the Sn layer reduces the Sn melting risk

Solderability is maintained

MacDermid Enthone with Organic Metal Silver Pre-dip

Cleaner

Rin

se

Micro Etch

Rin

se


Pre-Dip

AgImmersion Tin

Sn (Cu)

Advantage of ORMECON CSN Technology

Eliminate Tin Melting Risk


Advantage of ORMECON CSN Technology

Eliminate Tin Melting Risk

ORMECON CSN Classic

Results After 2nd Reflow

Competitive ImSn

Results After 2nd Reflow

ORMECON CSN has reduced tin melting

Improved wetting performance during the second lead free reflow cycle

Less scrap for second side dewetting


Solder Spread Comparison

Lead-Free Solderability

Solder spread decreases with increasing lead free reflow cycles

Spread is higher for ORMECON CSN compared to a competitor process

ORMECON CSN

A Tin

Reflow status fresh 1x reflow 2x reflow 3x reflow 4x reflow 5x reflow

Sn - thickness 0.94 µm 0.22 µm 0.11 µm 0.05 µm 0.04 µm 0.03 µm

Spreading 257% 114% 108% 107% 101% 97%

Reflow status fresh 1x reflow 2x reflow 3x reflow 4x reflow 5x reflow

Sn - thickness 1.13 µm 0.32 µm 0.26 µm 0.22 µm 0.13 µm 0.11 µm

Spreading 286% 98% 105% 101% 95% 93%


Disadvantage of Depositing Ag and Sn Together

Lead-Free Solderability

With Ag in the immersion Sn bath, the competing interactions (e.g. immersion Ag and Sn) yielded inconsistent silver concentration and solderability.

* Preconditioned with 1x lead free reflows

No Ag Ag 1 Ag 2


Cu

Sn

Solder mask

Cu

Sn

Solder mask

dark field view bright field viewmouse bite

* A specialized test coupon (mouse bite coupon) can be used to evaluate the mousebite

Effective Mousebite ReductionWhat is Mousebite?


Mousebite was monitored in a cross test on both ORMECON CSN

and A lines

Company spec: < 7 µm surface & < 10 µm hole

Average Result: ORMECON CSN (IML Line) 1.8 µm

A Line 3.3 µm

Effective Mousebite ReductionComparison Study at Customer Z

-1.0

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

11.0

MB of IML line

MB of A line


ORMCEON CSN Technology

Effective Whisker Protection

The OM-Ag nano layer is incorporated into the Sn coating

Reduction in the internal stress due to inter-diffusion between Cu and Sn, which is the driving force for whiskers

Without OMP

7001 Predip

With OMP

7001 Predip

24.15 µm 5.94 µm

* 6 weeks in ambient condition


The silver in ORMECON CSN is only 0.3% and evenly distributed. The concentration is not highest at the surface but collects in two regions; one just under the surface (0.2 µm) and the other around the transition to the intermetallic phase (0.85 µm)

Tiefe [μm]

0 0,5 1,0 1,5 2,0 2,5 3,0

Massekonz. [%

]

0

10

20

30

40

50

60

70

80

90

100 Sn

Sn

Sn Sn

Ag

Ag

Ag AgCu

Cu

Cu Cu

P P P PS S S SC C C CN N N N

OO O ONa Na Na Na

Proben-Nr 12_273_4BeschreibungAuftrag 2K12609-4

Sn - s(100%)Ag - s(1%)

Cu - s(100%)P - s(1%)

S - s(1%)C - s(1%)

N - s(10%)O - s(10%)Na - s(1%)

Ag scale = 5%

ImSn Supplier A

PCB Shop O

Tiefe [μm]

0 0,5 1,0 1,5 2,0 2,5 3,0

Massekonz. [%

]

0

10

20

30

40

50

60

70

80

90

100

Sn

Sn Sn Sn

Ag

Ag Ag Ag

Cu

Cu Cu Cu

P P P PS S S SC C C C

N N N NO

O O ONa Na Na Na

Proben-Nr 12_273_1

BeschreibungAuftrag 2K12609-1

Sn - s(100%)

Ag - s(5%)Cu - s(100%)

P - s(1%)

S - s(1%)C - s(1%)

N - s(10%)

O - s(10%)

Na - s(1%)

Tiefe [μm]

0 0,5 1,0 1,5 2,0 2,5 3,0

Massekonz. [%

]

0

10

20

30

40

50

60

70

80

90

100

Sn

Sn

Sn Sn

Ag

Ag

AgAg

Cu

Cu

Cu Cu

Proben-Nr 12-273_6BeschreibungAuftrag 2K12609-6

Sn - s(100%)Ag - s(1%)

Cu - s(100%)

Ag scale = 1%

ORMECON CSN

PCB Shop S

Tiefe [μm]

0 0,5 1,0 1,5 2,0 2,5 3,0

Massekonz. [%

]

0

10

20

30

40

50

60

70

80

90

100 Sn

Sn

Sn Sn Ag Ag

Ag AgCu

Cu

Cu Cu

P P P PS S S SC C C CN N N N

OO O ONa Na Na Na

Proben-Nr 12_273_3

Beschreibung

Auftrag 2K12609-3

Sn - s(100%)Ag - s(1%)

Cu - s(100%)

P - s(1%)

S - s(1%)C - s(1%)

N - s(10%)

O - s(10%)Na - s(1%)

Comparison with Supplier A


The silver content in the tin layer of Supplier A tin layer is much higher (3%) and is distributed as a gradient. It decreases continually from the surface, where the highest concentration can be found.


All samples with different OM-Ag thickness show a maximum whisker length well below 50 µm after 32 weeks of testing

40-6020-403-20

70

60

50

40

30

20

10

0

OM-Ag (um)

Maxim

um

len

gth

(u

m)

Boxplot of Maximum Whisker Length (um)

ORMECON CSN Whisker Observation Data



Post-Treatment combination effectively cleans surface.

Significant reduction in rejects and returns for visual defects.

Delivers consistent, reproducible coating no discolouration.

Fewer Visual Defects Reduction in Surface Discolouration

ORMECON CSN boards

Before Reflow

ORMECON CSN boards

After 3 X IR Reflows


Create Value With MacDermid Enthone and ORMECON CSN

ORMECON® CSN Classic

Suppliers NOT

using OM Technology

Bath Make UpExended life/Reduced make-up

frequencyRequire fresh make-up each

year

Whisker ControlOM-Ag complex predip independant of Sn bath

Ag integrated in Sn bath, difficult to control

High risk of tin melting

Deposition RateSn deposition rate not

impacted by Sn(IV)

Sn depostion rate reduced by Sn(IV); Sn(IV) reduction

required

Energy DemandLow (recommended process

temp: 68°C)Higher energy demand

(72°C)

Surface Cleanliness

RAD, RPT post-dips assure surface cleanliness

Post-dip in optional, high risk of surface discoloration

22

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ormecon csn immersion tin - intercontifiles.interconti.cz/200000656-55c3b56b53/ormecon-csn.pdf ·...

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