1Scope This test is used to determine the total ionic con-tent extractable from on,and absorbed within,the surface of printed wiring boards(PWBs),for the purposes of process control.The conductivity of the extract solution is measured and the results are expressed as sodium chloride equivalence per unit area.
2Applicable Documents
IPC-TM-650Test Method2.3.25,Detection and Measure-ment of Ionizable Surface Contaminants by Resistivity of Sol-vent Extract(ROSE)
3Test Specimens
The test specimen may be any unpopulated PWB.The num-ber of specimens depends on the process control plan or product drawings/prints.
4Apparatus or Material
•An automated Resistivity of Solvent Extract(ROSE)tester
•Conductivity dip probe with appropriate meter with tem-perature compensation
•Hydrometer(0.800-0.900)for ROSE tester calibration •Thermometer for ROSE tester calibration
•Clean room(non-ionic)gloves or forceps
•KAPAK™plastic bags or equivalents(see6.9)
•Bag sealing equipment
•Water bath,capable of sustaining an80°C±2°C[176°F±3.6°F]temperature
端粒和端粒酶•Second water bath capable of sustaining a25°C±1°C [77°F±1.8°F]temperature
•Precision solvent measurement equipment,such as class A pipettes
•Volumetric glassware
•Plastic ware-high density polyethylene,polymethylpentene (polypentene)or equivalent.
•Extract solution:25%v/v deionized water(18MΩ-cm nomi-nal resistivity),75%v/v2-propanol(electronic or HPLC grade).No alternative solution or composition is allowed.•Sodium chloride-reagent grade
•Analytical balance accurate to0.0001grams
WARNING:2-propanol is a flammable material.The2-propanol/ water mixture is also flammable.Exercise caution when using this solution.
5Procedure
5.1Extraction
NOTE:Throughout this procedure,do not touch the sample boards with bare hands.Use the clean room gloves specified or use clean forceps.
5.1.1Calculate the surface area of the PWB using: Area(in cm2)=Length x Width x2
5.1.2Prepare a volume of extract solution specified in4. 5.1.3Using clean room gloves or clean forceps,place the
PWB into virgin KAPAK™bags.Choose the bag size to give at least an additional2.5cm[1.0in]on each side of the board to minimize the amount of extract solution used.Allow at least an additional5cm[2.0in]above the board top.
5.1.4Using a pipette or graduated cylinder,add a volume of the extract solution into the bag.The amo
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unt will depend on the area of the board surface.This usually varies from0.8 mL/cm2[5.2mL/in2]up to about3mL/cm2[19mL/in2].For example,a10cm x11.5cm[3.94in x4.53in]board would require about100mL of solution.The amount of solution should just cover the board completely when most of the air is forced out of the bag.
5.1.5Force most of the air from the bag and heat seal the bag.This involves contact with a hot metal bar.Take reason-able precautions to keep extract solution from contacting the hot bar.Alternatively,the top of the bag may be folded over and clipped shut.
5.1.6Place the bag(s)vertically in a water bath which has stabilized at80°C[176°F].Make sure that the boards do not float above the water line.Do not allow the water from the bath to enter the bag or for extract solution to leak out of the bag.
Material in this Test Methods Manual was voluntarily established by Technical Committees of IPC.This material is advisory only
and its use or adaptation is entirely voluntary.IPC disclaims all liability of any kind as to the use,application,or adaptation of this
material.Users are also wholly responsible for protecting themselves against all claims or liabilities for patent infringement.
Equipment referenced is for the convenience of the user and does not imply endorsement by IPC.
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5.1.7Allow the boards to extract in this manner for a period of time of60±5minutes.结肠
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5.1.8Following the extraction of 5.1.7,remove the bags from the water bath and allow the extract solution to cool for at least30minutes,with the specimen still in the bag. 5.1.9Using clean tongs or forceps,remove the PWB from the bag.
5.2Measurement–DIP Probe Method
5.2.1Calibration of Bridge This is essential in this method because there can be no correlation between resistivity/ conductivity readings and NaCl equivalents without calibra-tion.
5.2.1.1Prepare a standard NaCl solution from a weight of
dry reagent grade NaCl salt dissolved in deionized water to produce a final diluted concentration of0.06g/liter NaCl(5mL equals300µg NaCl).
5.2.1.2Place1liter of the2-propanol water solution(at the calibration temperature of the bridge in use)in a plastic bea-ker.
NOTE:The75%v/v2-propanol solution must be used in this calibration.Water cannot be used since it is not the test solu-tion used in the procedure.The test solution used in this cali-bration can be recleaned by passing through the DI column until the required resistivity/conductivity is obtained.
5.2.1.3From a50mL burette,add to the liter of test solu-tion,5mL of the standard0.06g/liter NaCl solution.Stir and measure resistivity/conductivity.
5.2.1.4From a50mL burette,add to the liter of test solu-tion,20additional mL of the standard0.06g/liter NaCl solu-tion,for a total of25mL.Stir and measure resistivity/ conductivity.
5.2.1.5From a50mL burette,add to the liter of test solu-tion,25additional mL of the standard0.06g/liter NaCl solu-tion,for a total of50mL.Stir and measure resistivity/ conductivity.
5.2.1.6Plot a three point nomogram of Conductivity vs. Solution Concentration(inµg/liter NaCl).See Figure1for example.You should get a linear relationship.Use a best fit line obtained with a piecewise linear method.5.2.2Test Procedure-DIP Probe
NOTE:If desired,this test can be run at other temperatures; however,the calibration process must be repeated for the alternative temperature.This calibration process need only be done once,providing the conductivity cell has not been exposed to harsh chemicals which would alter the cell con-stants.If the conductivity cell is routinely used on harsh chemical ,plating baths),then the calibration should be repeated before every test run.
5.2.2.1Place the Kapak™bags containing the extract solu-tions into the25°C[77°F]water bath and allow the extract solutions to reach25°C[77°F].
5.2.2.2Insert the conductivity probe into the Kapak™bag containing the room-temperature extract solution.It is impor-tant that the extract solution be measured at the same tem-perature used for the calibration solutions.Immerse the probe to a suitable depth.
NOTE:A‘‘suitable depth’’is one which covers the cell elec-trodes,but not an immersion which covers the wiring.Many cells are marked with a scribed line which indicates the proper immersion depth.
中央民族大学图书馆5.2.2.3Gently agitate the solution.Read the conductivity of the solution.The time between immersion of the cell and tak-ing the reading should be the same as used for the calibration curve.Sufficient time should be allowed for the reading to come to equilibrium(no change for two minutes).
Figure1Nomogram of Conductivity vs.Solution Concentration
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NOTE:Between measurements,rinse the cell with deionized water and leave the cell soaking in virgin extract solution. Never use a dry cell as this is bad technique.
5.2.2.4Using the linear relationship formed in 5.2.1.6, determine the concentration of sodium chloride correspond-ing to the conductivity reading.Use the equation given below to determine the total micrograms of sodium chloride equiva-lence per square centimeter(µg NaCl Eq./cm2)
Using the nomogram:
Conductivity of Unknown→
Concentration of Unknown
Concentration Volume of Extract Solution
(µg/liter)x(liter)
Extracted Surface Area(cm2)
=µg NaCl Eq./cm2
5.2.2.5If the conductivity of the unknown solution is outside of the bounds represented on the existing nomogram,then continue the technique used to generate the nomogram(see 5.2.1)until the bounds contain the conductivity of the unknown solution.
5.3Measurement–Static ROSE Tester Method NOTE:This section was developed using an Omegameter 600SMD with a10,000mL cell.Make appropriate changes to the procedure to accommodate other static ROSE testers. 5.3.1Perform a system verification check.
5.3.2Set the instrument to an appropriate amount of sol-vent volume.A target solution level should be1.5mL for one cm2of board surface.It is not necessary to cover the spray
jets(if applicable).If the lid is on the test cell,the CO
2
mixing is minimized.
5.3.3Enter the appropriate surface area into the instrument.
5.3.4To allow for the volume of solvent that is to be added, the instrument setup volume will be set at the minimum ,2300mL)plus the volume of solution in the extrac-tion ,100mL).
Dwell time or run time:2minutes
Pass/Fail Value:None
Begin the test and follow the test prompts.
Remove the cell cover.5.3.5Carefully open the test bag and quickly pour the extract solution into the test cell.To minimize CO
2
absorption, the addition should be made as quickly as possible and the cell cover quickly replaced.
5.3.6The instrument should very quickly reach equilibrium (10-15seconds)and then should remain essentially unchanged for the remainder of the two minute run.
5.3.7Log the reading in totalµg of sodium chloride equiva-lence per cm2.
5.3.8Static ROSE Calculation Example:
Testing a bare board,10cm x20cm[3.9in x7.9in] Surface area is10cm x20cm x2=400cm2[62in2]
Bag size should be about15cm x30cm[5.9in x12in]or larger
Extract solution would be about620mL
ROSE volume input to4620mL(4000mL to cover sprays and620mL from extraction)灭滴灵
ROSE tester cell volume set to4000mL.
Run time-2minutes
5.4Measurement–Dynamic ROSE Tester Method
5.4.1Perform a system verification check.
5.4.2Program the instrument with the appropriate surface area of the board.
5.4.3Cycle the instrument to the beginning cleanliness point.
5.4.4Carefully open the test bag and quickly pour the
extract solution into the test cell.To minimize CO
2
absorption, the addition should be made as quickly as possible and the cell cover quickly replaced.
5.4.5When the instrument completes the test,log the read-ing in totalµg of sodium chloride equivalence per cm2.
6Notes
6.1The background for this test method may be found in technical papers:
‘‘Rationale and Methodology for a Modified Resistivity of Sol-vent Extract Test Method,’’Philip W.Wittmer,IPC1995Fall Meeting Proceedings,S13-4.
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‘‘Ionic Cleanliness of LPISM Circuit Boards,’’Hank Sanftle-ben,IPC1995Fall Meeting Proceedings,S13-3.
6.2IPC-HDBK-001‘‘Handbook and Guide to the Require-ments for Soldered Electrical and Electronic Assemblies to Supplement ANSI/J-STD-001’’is another source for under-standing ROSE testing in general.
6.3This method may also be known as the modified-ROSE test.This test,due to its longer extraction time and higher extraction temperature,has demonstrated better correlation with the total ion determination by ion chromatography than IPC-TM-650,Test Method2.3.25,Detection and Measure-ment of Ionizable Surface Contaminants by Resistivity of Sol-vent Extract(ROSE)Method.However,as a bulk contamina-tion measurement method,it cannot distinguish individual ion species.
6.4From an analytical standpoint,the dip probe method is preferred as more repeatable than the automated ROSE testers and avoids many of the test ,CO
2 absorption from spray agitation)inherent in those instruments. It should be stressed that the dip probe method is an electro-lytic conductivity measurement and must be temperature-compensated.
6.5The dip probe calibrations can be run at multiple tem-peratures and a family of curves generated,widening the test window for use with this method.Higher temperatures,how-ever,will lead
to a faster2-propanol evaporation rate.The test can also be run with more dilute concentrations,prepared by series dilution.
6.6Conductivity cells have a‘‘constant’’value.Measured readings must be multiplied by this constant.Exposure to harsh chemicals may alter the constant,making a re-calibration necessary.Do not allow the probe used for this procedure to contact sticky,oily,or resinous ,flux).
6.7This procedure is intended to be a process control aid and as such,no pass-fail criteria is stated.It is expected that the fabricator/assembler will determine,with their customer, the necessary pass-fail criteria for their product by this method.6.8This method is best suited for monitoring and control of
a previously optimized process and should not be used to generate acceptance data unless part of a larger correlation study.Values generated with this method should be corre-lated to acceptable electrical performance if used for accep-tance.
6.9Kapak™500Series Bags can be obtained from: Kapak Corporation
5305Parkdale Drive
Minneapolis,MN55416
800-527-2557
www.kapak
A secondary source of Kapak™or Scotchpak™polyester bags or pouches can be obtained from:
VWR International
1310Goshen Parkway
West Chester,PA19380
Orders:1-800-932-5000
Web Orders:www.vwrsp
If an alternative to the Kapak™bag or Scotchpak™is desired,the bag must have the following characteristics:
•No extractable ionic material in75%2-propanol/25%DI water at80°C[176°F]for60minutes
•0.01cm[0.0039in]wall thickness minimum
•Heat sealable or mechanical seal
6.10There is some concern regarding ROSE tester cell size. Testing a2cm x2cm[0.79in x0.79in]board in a20,000 mL cell causes such a severe dilution as to cause the signal to be lost in the noise.A recommended cell size is5000mL or less.Smaller cell volumes will allow for a more measurable result.If a smaller cell,or running with a smaller test volume, are not an option,then the number of bare boards can be increased,all extracted separately,and the extract solutions all tested at once.
6.11When testing hybrids or microelectronics,be aware that2-propanol stored in glass containers can leach out materials such as sodium,borates,and silica.2-propanol stored in plastic containers does not have such a leaching problem.
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