1、1DS01-81 Rev. 2.0 (03/02)DuPont RistonSpecial W Series - W250Data Sheet and Processing InformationTechnical DataPhotopolymer Dry Film for most demandingPWB applicationsSIT (Secondary Image Transfer)Electroless/Electrolytic Ni/AuAggressive plating and tenting applicationsW250 showing 30 micron develo
2、ped image, 50 micron thick resist深圳市甘井高新材料有限公司 崔恒辉 136026001532DS01-81 Rev. 2.0 (03/02)This Data Sheet documents specific process information for Riston W250. For more back-ground on general Riston processing see the General Processing Guide.QUALITY CERTIFICATIONDUPONTS QUALITY SYSTEM IS ISOAPPROVED
3、All Riston products are produced under the moststringent manufacturing conditions. They havebeen thoroughly tested by DuPont during productionand are certified as conforming to the relevantproduction standards applicable at the time ofmanufacture. As DuPonts photopolymer manufac-turing facilities ar
4、e ISO 9001 approved, additionalcertification of product quality should not benecessary. However, should you require certifica-tion please contact your local DuPont representa-tive.PART 1: COPPER SURFACES ANDSURFACE PREPARATIONVendor Copper (Print high pressure (10 bar)final rinse (pH 6-8); hot air d
5、ry.Jet Pumice:3F or 4F grade, unfused, 15-20 % v/v, fines re-moval and replenishment per vendor recommenda-tions; high pressure (10 bar) final rinse (pH 6-8);hot air dry.Jet or Brush Aluminum Oxide (Al2O3):Follow vendor recommendations.Compressed Pad Brushing:500 grit; 1/4- 3/8“ brush foot print; hi
6、gh pressure (8-10 bar) final rinse (pH 6-8).Bristle Brushing500 grit; 1/4-3/8“ brush foot print; final rinse: 2-3bar, pH 6-8.PRODUCT FEATURES/ APPLICATIONS Negative working, aqueous processable dry filmphotoresist Specially formulated to allow high yield process-ing in the most demanding PWB applica
7、tions. Excellent Fine Line capability and low sensitivityto off-contact exposure. Extremely wide processing latitude. Outstanding flow characteristics and strongadhesion. Suitable for use in electroless Ni/Au and otheraggressive plating applicatins. Suitable for secondary image transfer (SIT) andsel
8、ective metallization processes with finefeature requirement.PRODUCT DESCRIPTION(Physical Parameters)Available Thicknesses: 50 micronsUnexposed Color in Yellow Light: GreenExposed Color in Daylight: BlueExposed Color in Yellow light: GreenPrint-Out (Phototropic) Image: StrongContrast to Copper: Stron
9、gOdor: LowSTORAGE hard water is acceptablebut may cause scale build up and clog nozzles.The lamination conditions recommended here willprovide good resist conformation and adhesion toclean copper surfaces, but there is no single set ofconditions which is optimum for every process.Hence, these condit
10、ions should be considered onlyas a starting point for process optimization.On rougher laminate or with marginally-prepared surfaces, yield can often be in-creased by laminating at higher roll tempera-tures. However, one must be cautious for severalreasons. All resists emit vapors during lamination,a
11、nd vapors increase at higher temperature. Whilehigher temperature usually benefits yield in a tentand etch process, it should not be used withoutadequate ventilation, since high vapor levels canpose a potential health hazard.Also, higher roll temperature may cause wrinkles and canadversely affect te
12、nting performance on larger holes. So, ifyou raise roll temperature above that recommended here,dont forget to consider these effects.Laminator ConditionsDuPont ASL-24 hard water is acceptablebut may cause scale build up and clog nozzles.Note: Reduced lamination roll pressure and/ortemperature may b
13、e required in tenting applicationsto avoid tent breakage and resist flow into through-holes.Vacuum LaminationVacuum lamination may be used to provide opti-mum conformation onto extreme surface topogra-phy (SIT processes, over conductors etc.).DuPont SMVLTemp.: 70 - 75CCycle Time: 45 - 60 secSlap Dow
14、n Time: 7-9 sec.Post-Lamination Hold Time Panels may be exposed immediately after lamination;however, allow enough time for panels to cool to roomtemperature before lamination (about 15 minutes; useaccumulator in in-line systems). Minimize hold time for best tenting performance. Maximum hold time (g
15、uidelines):Wet Lamination: 24 hoursDry Lamination: up to 3 daysHold times should be determined empiricallybased on the temperature and relative humidityof the storage area.Note: strip within 5 days after laminationPanel Handling/Racking/ Stacking:Preferred: Vertical racking in slotted racksLess desi
16、rable: StackingTo minimize adverse effects: stack on edge verti-cally after cooling; avoid dust and dirt trappingbetween panels; insert unlaminated panel betweenstack support and first laminated panel to protectlaminated panel. Unlaminated support panel shouldbe at least as big as the laminated pane
17、ls. Thinflexible innerlayers usually cannot be racked.Preferred techniques: hanging panels vertically orstacking on edge after cool down. If innerlayers arestacked horizontally in trays, the stack height shouldnot exceed 13 mm (1/2 inch). For panels with thinphotoresist and fine circuitry reduce sta
18、ck heightfurther.Individual racking of tent and etch panels is highlyrecommended.Performance on flexible SubstratesRiston W250 is also ideally suited for use on thincore laminate and flexible substrates.PART 3: EXPOSUREResolutionThe resolution data given here represent thesmallest lines and spaces o
19、btainable in a productionenvironment, with acceptable yields attained on fullsize panels with Riston W250 Series photoresist.They do not necessarily represent the finest spacewhich can be resolved nor the finest resist lineremaining intact after image development. In Optimized Production Environment
20、(hard contact, high intensity exposure, good develop-ment and rinse control): 50 micron L/S In Lab Environment: 30 micron L/SExposure Intensity 5 mW/cm2 at the photoresist surface for 8-10 mil L/Sresolution; higher intensities are desirable for finerL/S.Exposure Energy Vs “Steps Held”Riston W250mJ/c
21、m2 40 - 150RST 6 -18SST 6 - 10 Exposure energy (mJ/cm2) from International LightRadiometer model ZL400A with super slim UV probe. Steps held can vary by + 1 RST depending on thedevelopment breakpoint used. If panels are exposed when warm, there may be aslight increase in the steps held. RST = DuPont
22、 Riston 25-Step Density tablet; SST = Stouffer 21-Step Density Guide; “Step Held“ = last step covered 50% withphotoresist.深圳市甘井高新材料有限公司 崔恒辉 136026001535DS01-81 Rev. 2.0 (03/02)Vacuum Frame Operation Preferred Contact Mode: Hard Contact Check for small, immovable Newtons Rings as anindicator of good
23、contact between the panel,phototool, and vacuum frame cover. Use air bleeder veins to channel air to vacuum portand reduce vacuum drawdown time (with Mylar/Glass exposure frames). Bleeder Vein thickness: Same as panelPART 4: DEVELOPMENTChemistries/Make-up Potassium carbonate (potash; K2CO3)For make
24、up use either potassium carbonate powder,i.e. anhydrous (potash) K2CO3 or a liquid concentratesuch as DuPont D-4000 developer (40% concentrate):Working solution: 1.0 wt%. For 380 liters solution use6.8 liters of D-4000 or 3.8 kg. of anhydrous potassiumcarbonate. Sodium carbonate, anhydrous, ( soda a
25、sh), Na2CO3Working solution: 0.85 wt%. Use 0.0085 kg/liter Sodium carbonate, monohydrate; Na2CO3H2OWorking solution: 1.00 wt%. Use 0.01 kg/litersEquations to calculate required amountsfor desired wt% of working solutions: D-4000: liters (or gallons) D-4000 = wt% x sump volliters (or gallons) x 0.018
26、 K2CO3: kg K2CO3 = wt% x sump vol liters x 0.01lb. K2CO3 = wt % x sump vol gallons x 0.083 Na2CO3: kg Na2CO3 = wt% x sump vol liters x 0.01 lb.Na2CO3 = wt% x sump vol gallons x 0.083Control TestTitration of fresh developer solution (e.g. 25ml),before defoamer addition, with 0.1 N HCl to theMethyl Or
27、ange end point:wt% = N x ml HCl x FW / 20 x ml Sample(N= acid normality; FW = formula weight)FW of Na2CO3=106FW of Na2CO3H2O= 124FW of K2CO3 = 138DefoamersRiston W250 has been successfully used withoutdefoamer but this is highly equipment dependent .The need for defoamer and the amount requiredare d
28、ependent on water quality, carbonate purity,photoresist loading, and equipment design. Ifrequired, add 1.3 ml/liter (5 ml/gallon) ofFoamFree 940 , or BASFs Pluronic 31R1, orequivalent polyethylene-polypropylene glycol blockco-polymer. For batch operation: add defoamer during initial makeup; For auto
29、matic replenishment systems: adddefoamer directly to the sump in a high turbulencearea at a predetermined rate. Do not add defoamer tothe supply tank or to the replenishment solution. FoamFREE 940 has an inverse solubility curve andbecomes effective only above its cloud point. Anyexcessive foaming t
30、hat may be noticed belowoperating temperature should subside upon heating.Development Conditions Spray Pressure: 1.5 - 1.8 bar (22-25 psig) Spray Nozzles: high impact direct-fan nozzlespreferred; a combination of cone andfan nozzles may be preferred if filmtent breakage is experienced. Chemistry:Na2
31、CO3: 0.7-1.0 wt%; 0.85 wt% preferredNa2CO3H2O: 0.8-1.1 wt%; 1.0 wt% preferredK2CO3: 0.8-1.1 wt%; 1.0 wt% preferred Temperature: 27-35C (80-95F); 85F preferredDwell Time Breakpoint: 50-70% (60% preferred) Time in Developer (Dwell Time), at 1.5 - 1.8 bar (22-25psig) spray pressure, 60% breakpoint, 30C
32、, freshdeveloper solution at recommended carbonateconcentrations in a Chemcut 2000 developer:Riston W250: 45 - 52 secondsNote: Total time in developer = Time to cleanBreakpoint. Time to Clean (time in developer to wash off unex-posed resist): 30 seconds for Riston W250depending on conditions. Shorte
33、r times to clean are achieved at highertemperatures, higher carbonate concentrations, andhigher pressures. If developer conveyor speed is too fast for matchwith other in-line equipment: reduce soda ashconcentration to as low as 0.6wt%. Do not lowertemperature or spray pressure below recommendedlevel
34、s.深圳市甘井高新材料有限公司 崔恒辉 136026001536DS01-81 Rev. 2.0 (03/02)Post Development CureA post development cure may be necessary toachieve chemical resistance to successfully passharsh plating cycles. This step also reduces theeffect the resist may have on the plating bath , andthe frequency of carbon treatmen
35、t.A thermal bake of 1 hour 150C (300F) and/ora UV bump of 0.4 - 1.1 J/cm2 may be needed foroptimum performance.Each process is different, and the above data isintended to serve as a starting point for optimizationof a specific process.Resist Loading Resist Loading: 2-12 mil-ft2/gal (0.05 -0.30 mil-m
36、2/lt.)Note: this range gives a fairly constant time toclean; lower loadings result in shorter time to clean;higher loadings increase the time to clean.Rinsing 1/2 preferred. Drying: blow dry thoroughly.Controls: For batch processing: adjust conveyor speed tomaintain desired breakpoint; dump develope
37、r solutionwhen development time has become 50% longer thanfor fresh solution. Developer conveyor speed: see “Dwell Time”. Feed stop addition when pH 10.7 is reached.Hold Time after Development beforeEtching0-5 daysNote: minimize white light exposure during postdevelopment hold to prevent film embrit
38、tlement.Developer ResiduesW250 is a very clean-developing film which leavesalmost no residues. However, partial polymerizationof resist can generate developer residues which inturn cause copper spots in etching. Partial lightblockage in exposure frames by registration tooling,etc., can be a serious
39、problem in both manual andautomated exposure units, and must be avoided.Ideally, all exposed resist should be the same color,with good definition after development. Color fadein certain places after development indicates partialexposure from light blockage, which can causedeveloper residue and coppe
40、r spots. For a print andetch process, this can usually be prevented bymodifying artwork designs or by installing physicalbarriers to completely block light at problemlocations.Developer MaintenanceClean at least once a week to remove resistresidue, calcium carbonate (scale), defoamer, anddye from de
41、veloped resist. Dye build-up can beminimized by the use of anti-foam.PART 5: PLATINGW250 is suitable for a variety of metallizationprocesses including electroless nickel and gold,electrolytic copper, tin, tin-lead, nickel and gold.PART 6: ETCHINGRiston W250 resist is compatible with most acidetchant
42、s, e.g. cupric chloride (free HCl normality 3.0 N), H2O2/H2SO4, and ferric chloride.W250 is also compatible with most alkalineanmonical etchants.PART 7: STRIPPINGAqueous Caustic (NaOH or KOH)Conveyorized Stripping Stripper Dwell Times (seconds) at 55C (130F),25psig (1.7 kg/cm2), over recommended exp
43、osurerange:深圳市甘井高新材料有限公司 崔恒辉 136026001537DS01-81 Rev. 2.0 (03/02)Stripping Dwell TimesW2501.5 wt% (15 g/l) NaOH 1003.0 wt% (30 g/l) NaOH 701.5 wt% (15 g/l) KOH 1403.0 wt% (30 g/l) KOH 70Note: Dwell Time = 2x Time to strip resist High caustic concentrations produce larger skin sizesand higher loading
44、 capabilities. KOH generally produces smaller skin sizes thanNaOH.Particle Size at 1.5% NaOH: 5-10mmParticle Size at 3.0% NaOH: SheetParticle Size at KOH: 2-4mm Solubility of Stripped Particles: Nearly Insoluble Rate of dissolution ofStripped Particles: Very Slow Physical Characteristics ofStripped
45、Particles : Non sticky Higher stripping temperature increases the strippingrate. Stripping rate can be increased with higher impactsprays. Use higher pressures and/or high-impactspray nozzles. Avoid low impact deflector nozzles. Time to strip increases with white light exposure. A20% increase in str
46、ip time over 8 days exposure is notunusual. Higher levels of exposure may slightly increase Time-to-Strip.For example, with Riston W250 Series the dwelltime increases 20% from RST of 18 compared toRST of 10.DefoamersAdditives for foam control may not be requireddepending on equipment design and oper
47、ation.However, if defoamer is needed, use DuPontFoamFREE 940 at 2ml/gallon(0.5 ml/ liter) forresist loadings up to 25 mil-ft2/gal (0.6 mil-m2/liter).Controls/ Solution Maintenance: Preferred: Continuous replenishment (feed & bleed)using board count.Maintain resist loading at 20 mil-square feet/ gall
48、on(0.5 mil-m2/liter) Batch: up to 25 mil-square feet/ gallon (0.6 mil-m2/liter). Maintain breakpoint at 50% by loweringconveyor speed or by starting batch stripping with alower breakpoint and changing the solution oncebreakpoint moves above 50%. However, lowbreakpoints can cause copper oxidation.Fil
49、tration SystemsW250 Series film is formulated to obtain relativelyinsoluble skins in stripping. This can extend strip-ping solution life greatly. However, in machineswhich do not have automatic skin removal, filterbaskets must be emptied more frequently to preventfilter “blinding“.For W250, and other non-dissolving resists, it is apractical necessity that spray stripping equipmentcontain a filtration system to collect and removeresist skins to avoid nozzle clogging, to extendstripper life, and
