Inkjet resist inks Krishna Balantrapu
OUTLINE Conventional Vs. Inkjet-Cost Savings Inkjet Material Design Inkjet Equipment-Lunaris Future work 2
DOW-R&D DRIVERS FOR NEW PRODUCT DEVELOPMENT Technology Need Requirements for end device New specifications New material choices Smaller feature size Different feature shape New equipment sets Environmental New legislative requirements Expense in waste treating Concern regarding hazards REACH and RoHS Cost Raw material costs high Fluctuating prices Reduce risk
CONVENTIONAL Vs. INKJET ETCH RESIST Dry film Process New Inkjet Process 4 - Do not share without permission
LEAN MANUFACTURING WITH INKJET 35 Average Minutes Cycle Time/Panel for Imaging 30 32 25 20 15 10 5 0 Conventional LDI Lunaris 7 1.2 *For conventional processing, imaging includes lamination, artwork exposure, mylar peel, developing, and first artcle check. LDI is the same sequence minus first article. Lunaris on the other hand, is just one simple step. 5
LABOR COST Throughput Dry Film (manual) Dry Film (automatic) LDI Inkjet Panel output/ hr 35 40 35 50 Production hrs/day 23 20 23 18 Labor Photo plotter 1 1 - - Pre-clean & Laminate 2 2 2 1 Printing 2 2 1 - DES 2 2 2 1 AOI 2 2 2 - Labor cost/panel $ 4.14 $ 6.21 $ 4.83 $ 1.38 Labor cost/year $828,000 1,242,000 $ 966,000 $ 276,000
PROCESS CHEMISTRY COSTS Process step Liters/day of waste Annual cost of chemicals & waste treatment Inkjet material costs Pre-clean 120 $14,300 $7,150 Pre-clean rinse 3600 $4,100 $2,050 Comments No micro etch Vs. dry film Developer 310 $12,100 - - Develop rinse 3600 $3,500 - - Etcher 1440 $182,400 $182,400 Etching rinse 3600 $4,900 $4,900 Stripper Stripper rinse 240 3600 $17,700 $4,050 $8,850 $2,025 Inkjet strips as sheets Ink thickness is 50% of dry film resist Total 16510 $243,050 $207,375 1 m/min line speed@ 35 micron Cu per side and 18 X 24 panels
OVERALL SAVINGS OF JET-RESIST ENABLED PCB FAB FACTORY First fully digital, green, automated PCB factory in the world 3-4 year ROI vs China Outsource at Whelen Avg Cost per 18" x 24" Panel $70 $60 $50 $40 $30 $20 $10 $0 China Outsource Whelen Captive Shop
CONNECTOR REEL TO REEL PLATING-LITHOJET 250 Band masking seepage Coating in non functional areas
CONVENTIONAL MASKING VS. INKJET PLATING RESIST Physical masking Inkjet masking Spot/brush plating tank Gold Inkjet resist Print heads Gold plating tank Resist strip tank Gold Excessive gold bleed ZERO gold bleed Set up time too long Mobile unit which can be fit in any connector line Cannot be used for tight geometries Excessive mask maintenance Excess gold still has to be recovered Coverage zone capability on connector parts ranges from 250 X 250 µm to 3 X 3 Alignment accuracy of ± 100 µm Can be used at line speeds up to 35ft/min No gold recovery step
Cost savings/line Line speed (ft/min) Annual ink volume ( kg) Annual Au cost ( 30 µin thick and 20% seepage) 10 250 kg $ 820000 20 500 kg $1600000 30 750 kg $ 2500000 40 1000 kg $3200000 Calculations based on: Strip width: 1 Resist thickness : 15 µm Metal area after connector is formed: 50% Plated area after connector is formed: 20% of metal Masking area : ~ 60% of the metal Working days: 250 11
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ADVANTAGE FOR HIGH RESOLUTION DESIGN General Inkjet ink LithoJet System Inkjet Head Inkjet Head LithoJet material is formulated for minimizing spreading after jetting After jetting, Ink is spreading. à Limitation for high resolution 13
PRE-TREATMENT No shorts or Cu spots due to the lock-in resist to a salt spot since there is no developer No redeposit of debris prior to etch 14
MECHANIAL STRENGTH Pencil hardness after UV cure 3 H 15
CHEMICAL RESISTANCE S LithoJet ink on High Carbon Steel following an aggressive Ferric Chloride Etch S Etch Depth is approx. 20 mils deep S Good Ink integrity after etching S Customers have had success with etching times over 3 hours Ink Overhang 16
POST ETCH RESULTS
MATERIAL WASTE COMPARISON ETCH RESIST Inkjet Functional Material Conventional 25 µm Dry Film Inkjet Resist LithoJet inks are 100% solids and do not contain any VOCs 18
PACKAGING COMPARISON Dry Film Roll 24 in x 500 ft = 167 panels Includes: Box, End Caps, Core, Wrapper, PET Cover Sheet, and Release Sheet Inkjet container 750g = 300 panels double sided Inkjet ink saves a lot of storage space and storage costs associated with the dry film No cold storage required for LithoJet inks 19
LITHOJET 223 ETCH RESIST Inkjet Head Type Jetting Temperature (@ 8-10 cp) Viscosity at Room Temp. Surface Tension Feature Resolution Curing Energy Curing / Pinning Wavelength Pencil Hardness after Curing Color Etch Compatibility Stripping Method Stripping Time Plating Compatibility Applied Thickness Stability At Jetting Temperature Dimatix, OCE, Xerox, Piezoelectric heads 85-90 C Semi-solid below 60C ~ 28-30 dynes/cm 30 µm printed gap; 70 µm printed feature (SE-128) 1000-1500 mj/cm 2 @ 365 nm peak UVA and/or UVB H-3H (Cure Dependent) Blue Green Acid copper etch and alkaline ammoniacal etch Surface strip 446-1 @ 50 C. Strips as insoluble particles ~60-90 sec. with spray agitation Acid and Alkaline Plating compatible ~ 10-25 µm (dpi dependant) ~ 10 days 20
ADVANTAGES OF LITHOJET Photolithography Alternative Faster Job Turns Direct CAD to image Shorter change-over times Reduced Work In Process (WIP) Smaller batch sizes become practical Green Chemistry 100% solids, no VOCs Low waste, low process steps Achieve High Resolution Advantages of Hot Melt low spread Higher Yields Elimination of repeating mask defects Reduction in alignment / scaling defects Possibility for Various Electronic Devices Fabrication 21
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PIEZOELECTRIC INKJET DROP EJECTION Drop-on-Demand printing deposits single drops of material Primary technique for electronic imaging is a piezoelectric inkjet print head 1. Rest 2. Fill Chamber 3. Fire 4. Drop Eject + - - Voltage 100 3.2 Standard Square Wave 13.0 1.2 0 Rise Time Pulse Width 23 Fall Time
WHAT YOU SEE IS WHAT YOU ETCH Pre etch* Post etch* Resist line width (track) 100 µm 75 µm Line width variation 3σ +/- 10 µm 3σ +/- 10 µm* Space (gap) 50 µm 75 µm Front-to-Back Alignment +/- 15 µm Same-Side Alignment +/- 10 µm Full IQI (AOI) Yes Throughput cores/hour ** 50 Throughput sides/hour ** 100 Substrate size 24 X 24 Panel thickness 0,035 2,5 mm * Typical 2 ounce copper example from Beta Site. Lower cu weights will have better tolerances ** Panel size 610 x 533 mm
PATENTED INKJET TECHNOLOGY Without a Print Strategy. CAM data Raster data Nozzle output Etch Resist Uncontrolled flow With Advanced Print Strategy. CAM data Raster data Inkflow calculations based on procédé 26pl drop 65µm spot 10µm panel accuracy Output
RESOLUTION IN SCAN DIRECTION Combination of table speed and frequency results in Y-dpi Frequency in Hertz dpi = Table speed in in/sec 30 pl Head Drops merge ~ 500 dpi with 50um drop size Example One: f=1500 Hz dpi = 1500/10 = 225 Table speed = 10 m/min Example Two: f=3000 Hz dpi = 3000/10 = 450 Table speed = 10 m/min Thickness of ink will increase due to overlap! Example Three: f=6000 Hz dpi = 60000/10 = 900 Table speed = 10 m/min 26
RESOLUTION IN ORTHOGONAL DIRECTION Example 20 mils = 50 dpi native Spectra SE-128 One head / One pass 10 mils = 100 dpi interlaced 2nd head / 2nd pass 27
PRINTED LINES Edge roughness <10 µm pre-etch 2 8
REDUNDANCY 20 heads printing 40 heads predicting 3 heads positioned same raster line 60 heads, 15360 nozzles in a virtual beam
100% IMAGE QUALITY INSPECTION Inline-product AOI: IQI Check against CAM Info Check at process speed for errors Detect Opens & Mouse Bites (Missing ink) 12345 Text Used for Product Calibration Approval of every printed panel (prior to etching) Check for Shorts & Filter Spots 3 0
LUNARIS @ WHELEN The first fully digital inner and outer layer printer based on ink-jet technology Area requirement placement :6000x3600x3000 mm (LxBxH)
LUNARIS IN PRODUCTION 32
ROADMAP 33
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