Validity of the IPC R.O.S.E. IPC

Method 2.3.25 Researched

IPC APEX 2010 Technical Conference

Dr. Mike Bixenman, Kyzen Corp.

Steve Stach, AAT

April 6, 2010

Agenda

• Why is Cleanliness Testing Important?

• What is a “ROSE” Cleanliness Test?

• Miniaturization and Flux Changes

• R.O.S.E. Testing Limitations

• Improving R.O.S.E. Testing

• Inferences from the Data Findings

• Conclusions

Cause of Fire

No single ignition source of the fire was

conclusively identified.

Determination

The most probable initiator was an electrical

arc in the sector between the -Y and +Z

spacecraft axes

January 27, 1967

How Circuit Board Residues

Affects Reliability? • Ionic Residues Facilitate Electro-Chemical Reactions

– Promotes Dendrites, Conductive Anodic Filaments

• Bulk Residues Create Cross Talk in High Speed Circuits

– Degrades 10 Gigahertz signals, Matched Impedance Lines

• Bulk Residues Trap other Contaminations

– Finger soils, other fluxes, chemicals, particulate

+

Image courtesy of NASA

History of the Cleanliness Test

• In the 1960’s

– DoD concerned about PCB failure

– Ionic contamination cited at the root cause

• Quality assurance and process control needed

• Task Force Objectives

– Quantitative process control method

– Detect ionic contamination

– Establish Pass / Fail criteria

What is a “ROSE” test

“Resistivity Of Solvent Extract”

• Industry standard test for circuit board cleanliness

(Mil-P-28809 in 1971)

• Measures the ionizable residues remaining on a

circuit board or assembly

0 1 2 3 4

Ionic Concentration (NaCl equivalent PPB)

1/R

(Conductance

µSiemens)

Manual ROSE Method

• Procedure

– Rinse each board with

50ml of reagent grade IPA

and H20 in a 75%/25%

mixture per inch square

– Measure the resistance

drop

Automatic “ROSE” testers

• Automated “ROSE” testers were developed

• Using Spray-under-immersion to minimize CO2

interference

• Deionization filters wereused to re-new IPA/water test

solution

Payback - Circuit Board Cleanliness?

• Manufacturing ROI - Improved Yields

• Product ROI – Better Product Performance

• Service ROI – Happy Customers

Miniaturization and New Fluxes

Miniaturization

• Increases soldering complexities

– Wetting

– Surface tension

– Oxidation resistance

– Oxygen barrier

• Flux residues bridge conductors

High Density Components

• Challenge the definition of circuit board cleanliness

• No good method for detecting residues under components

1970’s 1980’s 1990’s 2000’s

• QFNs

• 0.16” Centers

• Lead Free

• Lead Free

Fluxes

• Very High

Density• QFPs

• BGAs

• 0.20” Centers

• NC & WS

Fluxes

• High Density• Thru Hole• 0.1” Centers• Wave Solder• Active

Fluxes

• SMT

• 0.05” Centers

• Reflow Solder

• RMA Fluxes

• 2 sided

boards

Manual ROSE

ROSE TesterSMT Tester

PCB Assy & ROSE

Trend Lines

ROSE Testing Limitations

ROSE Limitations

• Initially designed for Rosin based fluxes

• IPA and/or water is not a good extraction

solvent for modern day fluxes

– Higher temperature reflow profiles

– New temperature resins and polymers

– Higher flux activity required

Improving ROSE Testing

Rethink the ROSE Test Platform

• Two driving factors

1. Extraction solvent (Static Dissolution Rate)

• To completely dissolve the residues

2. Higher Energy (Dynamic Dissolution Rate)

• Shorter test times

Like Dissolves Like

Teas Chart showing Hansen Solubility Ranges

Engineered Extraction Solvents

Innovative Extraction Solvents

• Flux residues differences

1. Characterize flux residues

2. Place fluxes with similar solubility in classes

3. Engineered extraction solvents that dissolve

flux residues

Response

Like Dissolves Like

Modern

Fluxes

Test Methodology

Solubility Testing

1. Two extraction solvents

tested

1. IPA / H20

2. Engineered extraction

solvent

2. Four flux families tested

1. Water Soluble ~ Lead-Free

2. Rosin ~ Tin-Lead

3. No-Clean ~ Tin-Lead

4. No-Clean ~ Lead-Free

3. Static time = 10 minutes

4. Temperature

• 20C

• 40C

• 60C

Flux Classification Extraction Solvent Time

Shaker

Table Grade

Visual

Cleanliness

IPA/H2O 10 min. 100 RPM (1-6)

Extration Solvent 10 min. 100 RPM (1-6)

IPA/H2O 10 min. 100 RPM (1-6)

Extration Solvent 10 min. 100 RPM (1-6)

IPA/H2O 10 min. 100 RPM (1-6)

Extration Solvent 10 min. 100 RPM (1-6)

IPA/H2O 10 min. 100 RPM (1-6)

Extration Solvent 10 min. 100 RPM (1-6)

IPA/H2O 10 min. 100 RPM (1-6)

Extration Solvent 10 min. 100 RPM (1-6)

IPA/H2O 10 min. 100 RPM (1-6)

Extration Solvent 10 min. 100 RPM (1-6)

IPA/H2O 10 min. 100 RPM (1-6)

Extration Solvent 10 min. 100 RPM (1-6)

IPA/H2O 10 min. 100 RPM (1-6)

Extration Solvent 10 min. 100 RPM (1-6)

IPA/H2O 10 min. 100 RPM (1-6)

Extration Solvent 10 min. 100 RPM (1-6)

IPA/H2O 10 min. 100 RPM (1-6)

Extration Solvent 10 min. 100 RPM (1-6)

IPA/H2O 10 min. 100 RPM (1-6)

Extration Solvent 10 min. 100 RPM (1-6)

IPA/H2O 10 min. 100 RPM (1-6)

Extration Solvent 10 min. 100 RPM (1-6)

No-Clean

Tin-Lead 3

No-Clean

Lead-Free 1

No-Clean

Lead-Free 2

No-Clean

Lead-Free 3

Rosin

Tin-Lead 1

Rosin

Tin-Lead 2

Rosin

Tin-Lead 3

No-Clean

Tin-Lead 1

Water Soluble

Lead-Free 1

Water Soluble

Lead-Free 2

Water Soluble

Lead-Free 3

No-Clean

Tin-Lead 2

Water Soluble Lead-Free 1

ReagentGrade

Table 120C Image 40C Image 60 C Image

IPA/H2O

1 @ 20C

1 @ 40C

1 @ 60C

New

Reagent

Design

1 @ 20C

1 @ 40C

1 @ 60C

Water Soluble Lead-Free 2

ReagentGrade

Table 120C Image 40C Image 60 C Image

IPA/H2O

1 @ 20C

1 @ 40C

1 @ 60C

New

Reagent

Design

1 @ 20C

1 @ 40C

1 @ 60C

Water Soluble Lead-Free 3

ReagentGrade

Table 120C Image 40C Image 60 C Image

IPA/H2O

1 @ 20C

1 @ 40C

1 @ 60C

New

Reagent

Design

1 @ 20C

1 @ 40C

1 @ 60C

Rosin ~ Tin-Lead 1

ReagentGrade

Table 120C Image 40C Image 60 C Image

IPA/H2O

1 @ 20C

1 @ 40C

1 @ 60C

New

Reagent

Design

1 @ 20C

1 @ 40C

1 @ 60C

Rosin ~ Tin-Lead 2

ReagentGrade

Table 120C Image 40C Image 60 C Image

IPA/H2O

1 @ 20C

1 @ 40C

1 @ 60C

New

Reagent

Design

1 @ 20C

1 @ 40C

1 @ 60C

Rosin ~ Tin-Lead 3

ReagentGrade

Table 120C Image 40C Image 60 C Image

IPA/H2O

1 @ 20C

1 @ 40C

1 @ 60C

New

Reagent

Design

1 @ 20C

1 @ 40C

1 @ 60C

No-Clean ~ Tin-Lead 1

ReagentGrade

Table 120C Image 40C Image 60 C Image

IPA/H2O

1 @ 20C

1 @ 40C

1 @ 60C

New

Reagent

Design

1 @ 20C

1 @ 40C

1 @ 60C

No-Clean ~ Tin-Lead 2

ReagentGrade

Table 120C Image 40C Image 60 C Image

IPA/H2O

1 @ 20C

1 @ 40C

1 @ 60C

New

Reagent

Design

1 @ 20C

1 @ 40C

1 @ 60C

No-Clean ~ Tin-Lead 3

ReagentGrade

Table 120C Image 40C Image 60 C Image

IPA/H2O

1 @ 20C

1 @ 40C

1 @ 60C

New

Reagent

Design

1 @ 20C

1 @ 40C

1 @ 60C

No-Clean ~ Lead-Free 1

ReagentGrade

Table 120C Image 40C Image 60 C Image

IPA/H2O

1 @ 20C

1 @ 40C

1 @ 60C

New

Reagent

Design

1 @ 20C

1 @ 40C

1 @ 60C

No-Clean ~ Lead-Free 2

ReagentGrade

Table 120C Image 40C Image 60 C Image

IPA/H2O

1 @ 20C

1 @ 40C

1 @ 60C

New

Reagent

Design

1 @ 20C

1 @ 40C

1 @ 60C

No-Clean ~ Lead-Free 3

ReagentGrade

Table 120C Image 40C Image 60 C Image

IPA/H2O

1 @ 20C

1 @ 40C

1 @ 60C

New

Reagent

Design

1 @ 20C

1 @ 40C

1 @ 60C

Summary of Data Findings

0.00

1.00

2.00

3.00

4.00

5.00

6.00

WS

1

Lead_F

ree

WS

2

Lead_F

ree

WS

3

Lead_F

ree

Rosin

1

Tin

_Lead

Rosin

2

Tin

_Lead

Rosin

3

Tin

_Lead

No-C

lean 1

Tin

_Lead

No-C

lean 2

Tin

_Lead

No-C

lean 3

Tin

_Lead

No-C

lean 1

Lead_F

ree

No-C

lean 2

Lead_F

ree

No-C

lean 3

Lead_F

ree

IPA / H2O @ 20°C IPA / H2O @ 40°C IPA / H2O @ 60°C

New Reagent @ 20°C New Reagent @ 40°C New Reagent @ 60°C

Score

Inferences from the Data

• IPA/H2O does not dissolve many of today’s

flux residues

• We need engineered extraction solvent to

dissolve/test flux residues

• More than one engineered solvent may be

needed depending on flux type

• The data indicates that temperature can

accelerate dissolution of most flux residues

Our Industry Needs ROSE Test

Improvements

• Engineer/test new solvent blends

• Develop/build new test instrument compatible with the new test solvents

• Evaluate dynamic energy methods to accelerate test

• Establish test sensitivity levels sufficient to detect flux trapped under critical parts