Dimensional Stability, Glass Reinforced Thin …

1 ScopeThis procedure defines a test method used todetermine Dimensional stability of Glass Reinforced , copper-clad, thin laminates intended for use in rigid multilayer test is appropriate for checking material consistency. It isnot intended for defining suitability of the raw material to beused in a specific printed board product or Applicable DocumentsIPC-TR-483 Dimensional stability Testing of Thin Lami-nates Test SpecimenThe specimen shall be 300 mm x 280mm [12 in x 11 in] in size with the warp direction in the 300mm dimension. A minimum of three specimens is required perinspection lot. When evaluating laminate sheets, specimensshould be taken from opposite diagonal corners and from thecenter of the sheet.

2 For precut panels three randomly selectedpanels shall be used to obtain the test measurement apparatus shall be capable of mea-suring the specimen within an accuracy of mm[ in], over 250 mm [ in] dimension. (Supergauge, orequivalent, may be used.) used for baking must be of the air circulating typeand capable of 2 C control. The recovery time of the tem-perature must be less than 15 minutes after specimens areplaced in the stabilization chamber (drying cabinet) containing cal-cium chloride or silica gel capable of maintaining less than 20RH at 21 2 Test Preparation of the the specimen for traceability in the identificationarea (see Figure 1).

3 No mechanical or chemical pre-cleaning ispermitted on the the four location points (see Figure 1) by drill-ing or distances Fl, F2, W1, and W2 utilizing theapparatus defined in paragraph Define distances to thenearest microns [ in]; the last digit of the readingmay be estimated. Record all values as initial optical measurement must be used, a rigid plateshall maintain the test specimen in a flat and horizontal a 12 mm [ in] diameter tape dot over holesor scribe marks on side of laminate to be measured and apiece of 25 mm x 12 mm [ in x in] wide tape over iden-tifying 1 All dimensions are in inches. Fourmeasurements are required as indicated.

4 Locatemeasuring points approximately [ in] fromeach edge in the fill direction, and mm [ in] fromeach edge in the warp Institute for Interconnecting and Packaging Electronic Circuits2215 Sanders Road Northbrook, IL 60062-6135 IPC-TM-650 TEST METHODS stability , Glass Reinforced ThinLaminatesDate2/86 RevisionAOriginating Task GroupN/AMaterial in this Test Methods Manual was voluntarily established by Technical Committees of the IPC. 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 the Copper RemovalRemove copper by etching in cupricchloride containing spray etcher at less than 50 C (122 F).

5 Rack samples upon exit from etcher, rinse, remove the tape,and air-dry laminate. Submit to bake cycle (paragraph )within four hours. (Note:Do not use resist stripping solutions.) only the thermal stress cycle is to be used proceed If not, proceed to Bake specimens at 105 C 5 C for four hours 10minutes. Vertically rack and place specimens in oven parallelto air flow with specimens being separated by a minimum of1/2 baking, immediately place the test specimens ina stabilization chamber (paragraph ). from stabilization chamber after one hour+1 2/-0 hours and, within 5 minutes, measure W11,W21,F11,and F21, using the apparatus defined in paragraph the thermal stress cycle is to be included in this test,proceed to paragraph If not, proceed to Thermal Stress CycleAfter the bake cycle measure-ment ( ), if immediate further processing is not feasible,place specimens in a stabilization chamber until test is a stabilization chamber is used, remove from thestabilization chamber and bake specimens at 150 C 5 C fortwo hours 5 minutes.

6 Vertically rack and place specimens inoven parallel to air flow, with specimens being separated by aminimum of 1/2 baking, immediately place the test specimen in astabilization chamber (paragraph ). from stabilization chamber after 1 hour + 1/ 2hour, -0 hours, and, within 5 minutes, measure W1, W2, F1,and F2, using the apparatus indicated in paragraph values as W12,W22,F12, and EvaluationDetermine the change in Dimensional sta-bility using the following Warp EvaluationsWarp=W11 W1W1x103=Mils/per inch for W1 after bakeW21 W2W2x103=Mils/per inch for W2 after bakeRepeat for W12and W22for after stressWhere W1/W2 = initial dimensions,W11/W21= after bake dimensions.

7 AndW12/W22= after thermal Fill EvaluationsFill=F11 F1F1x103=Mils/per inch for F1 after bakeF21 F2F2x103=Mils/per inch for F2 after bakeRepeat for F12and F22for after stressWhere F1/F2 = initial dimensions,F11/F21= after bake dimensions, andF12/F22= after thermal CalculationsTake the warp dimensions made on allthe measured specimens and determine the mean value forthe warp Dimensional stability characteristics of the laminateafter bake. Follow similar procedures on the calculations forthe fill Dimensional stability characteristics after bake. Extremevalues should be eliminated using the procedure defined inparagraph Similar measurements are made to calculatethe after thermal stress Dimensional stability Extreme Value EliminatedTake measurements insubgroup (warp or fill) and arrange in descending order ofmagnitude.

8 Solve for D, using procedure detailed in Table 1. Ifcalculated D is larger than the value of D shown in Table 2 forthe number of measurements being evaluated, the outlier issignificant and should be following is a checklist that should be usedby personnel responsible for performing this method in orderto provide repeatable/correlatable results. The IPC Dimen-sional stability Task Group responsible for the technical reporton Dimensional stability has determined that checklist items 2,5, 6, 9, 14, 15, 16 and 18 are critical to appropriate use of thisprocedure. (See IPC-TR-463.) stability , Glass Reinforced Thin LaminatesDate2/86 RevisionAPage2of3 CHECKLIST1.

9 Is the specimen size 300 mm x 280 mm[12 in x 11 in]?.. ____2. Is the warp direction properly identified? .. ____3. Were the four location points prepared by eitherdrilling or scribing?.. ____4. Were the measured points located approximately12 mm [ in] from each edge of the fill directionand approximately 25 mm [ in] from each edgeof the warp direction?.. ____5. Were the measurements taken from the samefeature location, , edge of the hole, center,scribe mark, etc? .. ____6. Were specimens processed without mechanicalor chemical pre-cleaning?.. ____7. Was cupric chloride etching with spray used toremove the copper? .. ____8. Was the temperature of the etching less than50 C?

10 ____9. The specimens were not exposed to resiststripping solution?.. ____10. Were specimens racked after removal frometching cycle?.. ____11. Is the oven used for baking capable of 2 Ccontrol and has a recovery time of less than15 minutes?.. ____12. Were specimens subjected to the bake cyclewithin 4 hours after etching?.. ____13. Were the specimens baked at 105 C 5 C for4 hours and vertically racked? .. ____14. Was the stabilization chamber capable ofmaintaining 20% RH maximum at 21 2 C? .. ____15. Was each specimen removed from stabilizationafter 1 hour + 1/2 hour -0 hours and were allmeasurements taken within 5 minutes?.. ____16. Were samples stored in stabilization chamberbetween after bake and after thermal stressmeasurements if immediate processing notfeasible?