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