PCB制程设计PCBA制程改善 DFM,DFT, Process, PCBA process_en.ppt

-Lead (Pb) -Chromium VI (Cr 6+) -Mercury (Hg) -Cadmium (Cd) -Polybrominated Biphenyls (PBB) -Polybrominated diphenyl ethers (PBDE)
SnPb SAC305
Melting point@183oC Melting point@217oC ( Sn-3.0Ag-0.5Cu)
87.54min 120min↑ N/A 100min↑ 37.53min 120min↑ 40min↑ N/A N/A 60min↑ 120min↑ 60min↑ 25min↑ 32.2 min 25min↑ N/A
No-dicy No-dicy No-dicy dicy dicy dicy Halogen Free Halogen Free Halogen Free Halogen Free Halogen Free dicy dicy dicy dicy dicy
Nanya Grace ITEQ Uniplus Nanya Grace Nanya ITEQ ITEQ Grace Grace Grace Grace Nanya Uniplus ITEQ
180±5 180±5℃ 180±5 170℃ 170±5 175±5℃ 150±5 155 145 135℃↑ 165℃↑ 145℃↑ 135℃↑ 140±5 135℃↑ 138
This is HAT PCB Panelization Due to limited G PCB capabilities, 5mm clearance are required. But L PCB supplier can accept 2mm.
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Second, find some potential issues, In order to sure to avoid problems for PCB or product assembly.
ENIG ElectrolessNi /Immersion Gold OSP Organic Solderability Preservatives
Difficult to get accept barrel fill for PTH;Must be processed within 48hrs after exposing boards;testing probe contact issue
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2.3, RoHS and Reach
RoHS : Restriction of the use of certain Hazardous Substances in electrical and electronic equipment. Take effect on 1 July 2006 and requires that such equipment must not contain the following chemicals:
DFT check Item including: Test coverage Test points on bottom/top side
Test point style
Test points need to added or modified
PTH, NPTH size
Solder side clearance Component clearance Copper connection Silkscreen Solder mask color UL logo/PCB vendor
PCBA Presentation
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Content Structure
1, DFM/DFT Introduction 2,PCB Process and Material 3, PCBA Process and SAC305 4, ICT Testing
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1, DFM/DFT Introduction
A,Small issue: no UL logo and PCB supplier information on the PCB. Actually, these words were printed under heatsink.
B,Balanced trace can prevent tombstone issue.
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The coupon indicates the number of the layer in a window. In case of a pressed multilayer, all layers are legible in the correct order.
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Draw a conclusion: It’s necessary to do DFx analysis before Gerber out. The value of DFx in PCBA design and manufacturing can be factored directly into the cost to produce a printed circuit board or assembly. If the PCB/PCBA is manufactured with defects, the manufacturers or LEM will have to bear the high cost for defects and repairs. The only way those defects can be identified is by tests or assembly.
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2.6, PCB surface finish
HAL SnAgCu Hot Air Solder Leveling, specified at LEM file Second choice at LEM file
Chemical Tin
Immersion Silver
Easier to process ;sufficient barrel fill for PTH;good solderability;no contact issue during ICT&FCT
R&D release Gerber files Flex receive data Flex run DFx
No
Meet DFx Guidelin e DFx Review
Yes
Confirm DFx issue LXX Draw a conclusion
Meet DFx
Yes
Guideline
No
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2.4, PCB Manufacture Process
Pre-engineering Pattern imaging
Etching
Laminating Drilling
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Desmear Cu plating Hole plugging Belt Sanding Cu plating Pattern imaging
C, Thermal relief for PTH (Plated Through Hole) components insufficient solder issue.
D,Critical issue: H component can’t be located in the center of magnetic Core. It affects PCBA assembly. We’re thinking of some methods to fix it.
1.2, DFx Benefits Improved design Decrease the time-to-market Decrease product cost Increase market share and profitability
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1.3,How to implement DFx process
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Solder Mask
Surface finish
Electrical test
Visual inspection
Shipping
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2.5,Laminate: 4 layer PCB
Kraft Paper
Iron Platform
Copper Prepreg Inner Prepreg Copper Iron Platform Kraft Paper
1.1, Why we need to do DFx (DFM/DFT) analysis for PCB checking before we finalize the Gerber files?
First, the PCBs or PCBAs we design should match with PCB or PCBA supplier capability.
Arbitrate for Non-conform issue *1 Closed Gerber out
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1.4,DFM/DFT check Item
DFM check Item including:
Tooling hole Mounting hole Fiducial marks
Board size
Post assembly issue
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2, PCB Process and Material
2.1, PCB Material
Lamilates Laminates NP-180 High Tg, High Td GA-180 IT-180TC UP-170 High Tg, Low Td NP-170 GA-170 NPG-TL IT-155GTC Low Tg, High Td IT-140GTC GA-HF14 GA-HF GA-150 GA-140 Low Tg , Low Td NP-140 UP-001TC IT-140TC Supplies ANSI Type FR-5 FR-5 FR-4 FR-4 FR-4 FR-4 FR-4 FR-4 FR-4 FR-4 FR-4 FR-4 FR-4 FR-4 FR-4 FR-4 Tg (℃ ) Td (℃ ) (5% weight Loss） 373.24 368 378 364 330.5 325 360 350 346 350 356 339 324 326 324 312 T260 T288 61.12min 90min↑ 60min↑ 60min↑ 23.55min 10min 24min↑ 60min↑ 60min↑ 60min↑ 90min↑ 15min↑ N/A N/A N/A N/A character Cost
130% 130% 130% 120% 120% 120% 120% 130% 120% 120% 125% 110% 100% 100% 100% 100%
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2.2,PCB character explain Tg: Glass transition temmperature T260: Test at 260oC Testing for solderability T288: Test at 288oC Testing for thermal stress at 3times@10seconds Dicy: Curing agent (Dicy-free for Anti-CAF ; Dicy-cure for process) Halogen: Halogen free good for CTE CTE: Temperature expansion coefficient Moisture absorption: below 5%