Transcript PCB design and fabrication - Rice University -

PCB design and fabrication
Lin Zhong
ELEC424, Fall 2010
Alternatives to PCB
• Breadboard
Breadboard prototype of the first IBM PC motherboard (1981)
http://www.yourdictionary.com/computer/breadboard
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Alternative to PCB (Contd.)
• Prefabricated PCB
Digikey.com
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Outline
• Basic concepts
• Introduction to EAGLE
• A small design project
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PCB design concepts
Function Design
Schematic
Component
library
Form factor
constraints
Layout
Routing
Design tools
Design rules
Production
Assembly
PCBexpress.com
Any local workshops
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Schematic Capture
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Layout and Routing
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Layout and Routing (Contd.)
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Component Library
• Component packaging
– Surface mount technology (SMT)
– Through-hole packaging
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Chip packaging
• Through-hole
– Dual in-line(DIP)
– Pin grid array (PGA)
• Surface mount
XC68020
– Quad flat (QFP)
– Ball grid array (BGA)
• Socket-based
– Land grid array (LGA)
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Core 2 Duo E6700
PCB design concepts
Function Design
Schematic
Component
library
Form factor
constraints
Layout
Routing
PCB design tool
Design rules
Production
Assembly
PCBexpress.com
Any local workshops
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Production
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Patterning (etching)
– Subtractive process to remove copper cover from a
preimpregnated substrate
– Silk-screen printing of etch-resistant inks
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Lamination
– Multilayer PCBs
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Drilling (vias and holes)
Coating (Solder and Solder mask /resist)
Printing text and symbols
http://www.unitechelectronics.com
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Assembly
• Pick & place machine
http://www.europlacer.com
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Assembly (Contd.)
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Assembly (Contd.)
• Soldering
– Wave soldering
– Reflow oven
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Wave soldering
• Waves of liquid solder
• Board passes the waves
• Large devices, high pin count, through-hole
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Reflow Oven
• Heat the board up (infrared)
• Small, surface mounted components
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Further Reading
• How motherboards are made
– http://www.pcstats.com/articleview.cfm?articleid=1722
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Caveats
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Locations of components
Orientation of components
Height of components
Polarity of components
SMT vs. Through-hole components
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PCB vs. IC
Function Design
Schematic
Component
library
Form factor
constraints
Layout
Routing
Design rules
Production
Integrated
Assembly
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PCB vs. IC production
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Polymer composite board
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Silicon wafer
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Silkscreen printing, photoengraving
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Photolithography
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Metallic (copper) wires
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Make devices such as transistors on
the wafer
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Modification
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Etch away copper
Copper wires
Place components on top of board
Soldering
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Ion implantation, furnace anneal
Deposition
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Physical vapor deposition (PVD)
Chemical vapor deposition (CVD)
Small scale and large # of devices
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