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PCB
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PCB Making Process
Artwork printingSingle Sided Process (Manual)Copper board cleaningLaminateUV ExposeDevelopEtchResist StripDrill holesCut to sizeNegative Process
Artwork printingSingle Sided Process (CNC)Copper board cleaningLaminateUV ExposeDevelopEtchResist StripDrill holesCut to sizeAlign artworkNegative Process
Artwork printingSingle Sided Process (Manual)Peel the protection layer of +ve boardUV ExposeDevelopEtchResist StripDrill holesCut to sizePositive ProcessUV ExposeDevelop
Process Comparison1 mil = 0.0254 mmHair = 4 6 mil = 0.1 0.15mm
Positive ProcessNegative ProcessManualCNCEasyHardMediumExpensiveCheaper (1/3)*Single sidedMultilayerUp to 1 milOnly up to 8 mil
Print ArtworkMEGA PhotoplotterLaser printerInkjet printerDarkerHigh resolutionCheapVery ExpensiveBest outputLow resolutionExpensive
PhotoresistPositive PhotoresistNegative PhotoresistLight sensitiveExposed to lightSolubleExposed to lightInsoluble
Laminate a Copper Board (Negative)Material:Dry Film Photoresist
UV ExposureFactor affect the output qualityPrinting sideUV Exposure UnitArtwork facing up or down.
UV Exposure = Ideal Case
UV Exposure = Actual Case
Correct Artwork Facing Position
Developing ProcessObjective:To remove soluble resist layerChemical:Developer NegativeCoustic soda (NaOH) PositiveNot fully developedFully developed
Etching ProcessObjective:To remove copper layerChemical:Ferric Chloride (FeCl3)
Factors Controlling Fine Line EtchingTheoretical Case
UNDER CUTFactors Controlling Fine Line EtchingActual Case
Equipment
Photoresist
Copper ThicknessFactors Controlling Fine Line EtchingSummary
The Finer The Line The Thinner The Copper35 =10 mil17 =4 8 mil5 =2 4 mil Factors Controlling Fine Line EtchingSummary
BeforeResist StripObjective:To remove resist layerChemical:Photoresist Stripper PC155 NegativeCoustic Soda (NaOH) PositiveAfter