Originating Task Group IPC-TM-650 TEST METHODS MANUAL

1 1 ScopeThis test is used to determine the total ionic con-tent extractable from on, and absorbed within, the surface ofprinted wiring boards (PWBs), for the purposes of processcontrol. The conductivity of the extract solution is measuredand the results are expressed as sodium chloride equivalenceper unit Applicable DocumentsIPC-TM-650 Test Method , Detection and Measure-ment of Ionizable Surface Contaminants by Resistivity of Sol-vent Extract (ROSE)3 Test SpecimensThe test specimen may be any unpopulated PWB. The num-ber of specimens depends on the process control plan orproduct Apparatus or Material An automated Resistivity of Solvent Extract (ROSE) tester Conductivity dip probe with appropriate meter with tem-perature compensation Hydrometer ( - ) for ROSE tester calibration Thermometer for ROSE tester calibration Clean room (non-ionic) gloves or forceps KAPAK plastic bags or equivalents (see ) Bag sealing equipment Water bath, capable of sustaining an 80 C 2 C [176 F F] temperature Second water bath capable of sustaining a 25 C 1 C[77 F F] temperature Precision solvent measurement equipment, such as class Apipettes Volumetric glassware Plastic ware - high density polyethylene, polymethylpentene(polypentene) or equivalent.

2 Extract solution: 25% v/v deionized water (18 M -cm nomi-nal resistivity), 75% v/v 2-propanol (electronic or HPLC grade). No alternative solution or composition is allowed. Sodium chloride - reagent grade Analytical balance accurate to gramsWARNING:2-propanol is a flammable material. The 2-propanol /water mixture is also flammable. Exercise caution when using ExtractionNOTE:Throughout this procedure, do not touch the sampleboards with bare hands. Use the clean room gloves specifiedor use clean the surface area of the PWB using:Area (in cm2) = Length x Width x a volume of extract solution specified in clean room gloves or clean forceps, place thePWB into virgin KAPAK bags. Choose the bag size to giveat least an additional cm [ in] on each side of the boardto minimize the amount of extract solution used. Allow at leastan additional 5 cm [ in] above the board a pipette or graduated cylinder, add a volume ofthe extract solution into the bag.

3 The amount will depend onthe area of the board surface. This usually varies from [ mL/in2] up to about 3 mL/cm2[19 mL/in2]. Forexample, a 10 cm x cm [ in x in] board wouldrequire about 100 mL of solution. The amount of solutionshould just cover the board completely when most of the airis forced out of the most of the air from the bag and heat seal thebag. This involves contact with a hot metal bar. Take reason-able precautions to keep extract solution from contacting thehot bar. Alternatively, the top of the bag may be folded overand clipped the bag(s) vertically in a water bath which hasstabilized at 80 C [176 F]. Make sure that the boards do notfloat above the water line. Do not allow the water from thebath to enter the bag or for extract solution to leak out of Sanders RoadNorthbrook, IL 60062-6135 IPC-TM-650 TEST METHODS Cleanliness Testing of Bare PWBsDateOctober 2000 RevisionOriginating Task GroupBare Board Cleanliness Assessment Task Group5-32cMaterial in this Test METHODS MANUAL was voluntarily established by Technical Committees of IPC.

4 This material is advisory onlyand its use or adaptation is entirely voluntary. IPC disclaims all liability of any kind as to the use, application, or adaptation of thismaterial. Users are also wholly responsible for protecting themselves against all claims or liabilities for patent referenced is for the convenience of the user and does not imply endorsement by CONNECTINGELECTRONICS INDUSTRIES the boards to extract in this manner for a periodof time of 60 5 the extraction of , remove the bagsfrom the water bath and allow the extract solution to cool forat least 30 minutes, with the specimen still in the clean tongs or forceps, remove the PWB fromthe Measurement DIP Probe Calibration of BridgeThis is essential in this methodbecause there can be no correlation between resistivity/conductivity readings and NaCl equivalents without a standard NaCl solution from a weight ofdry reagent grade NaCl salt dissolved in deionized water toproduce a final diluted concentration of g/liter NaCl (5 mLequals 300 g NaCl).

5 1 liter of the 2-propanol water solution (at thecalibration temperature of the bridge in use) in a plastic :The 75 % v/v 2-propanol solution must be used in thiscalibration. 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 columnuntil the required resistivity/conductivity is a 50 mL burette, add to the liter of test solu-tion, 5 mL of the standard g/liter NaCl solution. Stir andmeasure a 50 mL burette, add to the liter of test solu-tion, 20 additional mL of the standard g/liter NaCl solu-tion, for a total of 25 mL. Stir and measure a 50 mL burette, add to the liter of test solu-tion, 25 additional mL of the standard g/liter NaCl solu-tion, for a total of 50 mL. Stir and measure a three point nomogram of Conductivity Concentration (in g/liter NaCl).

6 See Figure 1 forexample. You should get a linear relationship. Use a best fitline obtained with a piecewise linear Test Procedure - DIP ProbeNOTE:If desired, this test can be run at other temperatures;however, the calibration process must be repeated for thealternative temperature. This calibration process need only bedone once, providing the conductivity cell has not beenexposed to harsh chemicals which would alter the cell con-stants. If the conductivity cell is routinely used on harshchemical solutions ( , plating baths), then the calibrationshould be repeated before every test the Kapak bags containing the extract solu-tions into the 25 C [77 F] water bath and allow the extractsolutions to reach 25 C [77 F]. the conductivity probe into the Kapak bagcontaining 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.

7 Immerse the probeto a suitable :A suitable depth is one which covers the cell elec-trodes, but not an immersion which covers the wiring. Manycells are marked with a scribed line which indicates the properimmersion agitate the solution. Read the conductivity ofthe solution. The time between immersion of the cell and tak-ing the reading should be the same as used for the calibrationcurve. Sufficient time should be allowed for the reading tocome to equilibrium (no change for two minutes).IPC-2325-1 Figure 1 Nomogram of Conductivity vs. SolutionConcentrationConductivitySolutio n Concentrationin micrograms Cleanliness Testing of Bare PWBsDateOctober 2000 RevisionPage2of4 NOTE:Between measurements, rinse the cell with deionizedwater and leave the cell soaking in virgin extract use a dry cell as this is bad the linear relationship formed in ,determine the concentration of sodium chloride correspond-ing to the conductivity reading.

8 Use the equation given belowto determine the total micrograms of sodium chloride equiva-lence per square centimeter ( g NaCl Eq. /cm2)Using the nomogram:Conductivity of Unknown Concentration of UnknownConcentrationVolume of Extract Solution( g/liter)x(liter)Extracted Surface Area(cm2)= g NaCl the conductivity of the unknown solution is outsideof the bounds represented on the existing nomogram, thencontinue the technique used to generate the nomogram ( ) until the bounds contain the conductivity of theunknown Measurement Static ROSE Tester MethodNOTE:This section was developed using an Omegameter600 SMD with a 10,000 mL cell. Make appropriate changes tothe procedure to accommodate other static ROSE a system verification the instrument to an appropriate amount of sol-vent volume. A target solution level should be mL for onecm2of board surface. It is not necessary to cover the sprayjets (if applicable).

9 If the lid is on the test cell, the CO2mixingis the appropriate surface area into the allow for the volume of solvent that is to be added,the instrument setup volume will be set at the minimum vol-ume ( , 2300 mL) plus the volume of solution in the extrac-tion bag ( , 100 mL).Dwell time or run time: 2 minutesPass / Fail Value: NoneBegin the test and follow the test the cell open the test bag and quickly pour theextract solution into the test cell. To minimize CO2absorption,the addition should be made as quickly as possible and thecell cover quickly instrument should very quickly reach equilibrium(10 - 15 seconds) and then should remain essentiallyunchanged for the remainder of the two minute the reading in total g of sodium chloride equiva-lence per Static ROSE Calculation Example:Testing a bare board, 10 cm x 20 cm [ in x in]Surface area is 10 cm x 20 cmx2=400cm2[62 in2]Bag size should be about 15 cm x 30 cm [ in x 12 in] orlargerExtract solution would be about 620 mLROSE volume input to 4620 mL (4000 mL to cover spraysand 620 mL from extraction)ROSE tester cell volume set to 4000 time - 2 Measurement Dynamic ROSE Tester a system verification the instrument with the appropriate surfacearea of the the instrument to the beginning open the test bag and quickly pour theextract solution into the test cell.

10 To minimize CO2absorption,the addition should be made as quickly as possible and thecell cover quickly the instrument completes the test, log the read-ing in total g of sodium chloride equivalence per background for this test method may be found intechnical papers: Rationale and Methodology for a Modified Resistivity of Sol-vent Extract Test Method, Philip W. Wittmer, IPC 1995 FallMeeting Proceedings, Cleanliness Testing of Bare PWBsDateOctober 2000 RevisionPage3of4 Ionic Cleanliness of LPISM Circuit Boards, Hank Sanftle-ben, IPC 1995 Fall Meeting Proceedings, Handbook and Guide to the Require-ments for Soldered Electrical and Electronic Assemblies toSupplement ANSI/J-STD-001 is another source for under-standing ROSE testing in method may also be known as the modified-ROSE test. This test, due to its longer extraction time and higherextraction temperature, has demonstrated better correlationwith the total ion determination by ion chromatography thanIPC-TM-650, Test Method , Detection and Measure-ment of Ionizable Surface Contaminants by Resistivity of Sol-vent Extract (ROSE) Method.