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