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TFE4180 Semiconductor Manufacturing Technology
Assembly and Packaging (Part 1)Chapter 20 : Semiconductor Manufacturing Technology by M. Quirk & J. Serda
Norwegian University of Science and Technology ( NTNU )
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Objectives
• Describe the general trends and design constraints ofassembly and packaging.
• State and discuss the traditional assembly methods.
• Describe the different traditional packaging options.
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• Final assembly and packaging, the back-end of the IC manufacturing process
• Two distinct processes
TFE4180 Semiconductor Manufacturing Technology
Introduction
4 Traditional Final Assembly and Packaging Process (Encapsulation)
Wafer test and sort
Wire bond
Die Separation
Plastic packaging Final packaging and test
Die Attach
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Four Important Functions of IC Packaging
1. Protection from environment and handling damage2. Interconnections for signals into and out of the chip3. Physical support of the chip4. Heat dissipation
Final product assembly: Final assembly of circuit boards into system
Metal leads for mounting onto printed circuit board
Pins
Pins are inserted into holes then soldered on rear of PCB.
Surface mount chips are soldered
on top of copper pads
ont the PCB.
Edge connector plugs into main system
PCB subassembly
Leads
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Traditional Assembly
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Four Steps of Traditional Assembly
• Backgrind• Die separation• Die attach• Wire bonding
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Backgrind
Rotating and oscillating spindle
Wafer on rotating chuck
Downforce
Table rotates only during indexing of wafers
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Advantages of Thinning Wafers
• Thinner wafers are easier to dice into chips• Improved thermal dissipation• Reduces thermal stresses in thin ULSI packages• Thinner chips reduce the size profile and weight of
Mixture of silver and glass particles suspended in an organic medium
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Wire Bonding
Electrical connection from chip surface to inner lead terminal
http://www.youtube.com/watch?v=VwOEQodkBrY
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Wire Connection Between Bonding Pad and Lead Frame
Moulding compound
LeadframeBonding pad
Die
Bond wire
Pin Tip
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Different Methods of Wire Bonding
• Thermocompression bonding
• Ultrasonic bonding
• Thermosonic ball bonding
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Thermocompression Wedge Bonding
Lead-terminal
Wedge bondDevice Bond pad
Heat
Pressure
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Ultrasonic Bonding
Wire
Wedge tool
(1)
Tool moves upward
Wire fed
(3)
Ultrasonic energy
Pressure
Lead Frame
(4)
Tool moves upward
Wire Breaks
(5)
(2)
Al bonding pad
Ultrasonic energy
Pressure
Die
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Ball Bonding
(2)
H2 TorchBall
(1)
Gold WireCapillary tool
(5)
Pressure and heat
Lead Frame
(6)
Tool moves upward
Wire Breaks at the bond
Bonding ball onpad
Pressure + Ultrasonic energy
Die
(3)
Tool moves upWire Fed
Die(4)
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Comparison Among Methods
Al, AuAuYes100-150 oCLowBall bonding
Al, AuAu, AlYes25 oCLowUltrasonic
Al, AuAu,No300-500 oCHighThermo Compression
PadWireUltrasonic energyTemperaturePressureType
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Wirebond Quality Measuring
• Visual inspection
• Pull test
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Visual Inspection
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Wire broken Wire missing Ball short circuit
• Used to detect wirebonding failures
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Pull Test
TerminalDevice
Chip under test
Hook
Holder
• Quantitative assessment of wirebond quality
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Traditional Packaging
• Metal packaging
• Plastic packaging
• Ceramic packaging
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Metal Packaging• Was common in early history of Semiconductor industry
• Still used today in special cases
Die
Gold‐plated header
Wirebonds
Leads
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Transistor Outline (TO) Type Metal Package
Used for packaging this type of devices:
• Semiconductor lasers, solid-state lasers with a diode pumping • Photodetectors, matrix photodetectors (CCD, FPA) • X-Ray detectors• Transistors, operational amplifiers, etc.
Voltage regulatorin TO3 package [2]
Laser diodein TO39 package [1]
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Plastic Packaging• Industry mainstay since its introduction• Highly popular due to:
o flexibility of the lead shape (gull-wings, J-leads, PIH) o high volume production techniques
DieLeadframe
Tie bar
Tie bar removallines
Leadframe [3]
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Packaging procedure• Molding • Deflashing• Component lead forming• Lead finish
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Plastic Packaging
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Plastic Dual In-Line Package (DIP)A type of through-hole mount package with lead pins protruding from both sides of the package.
Used for packaging this type of devices:
Microcontrollers, logic elements, memory, operational amplifiers, buffers, optocouplers, timers, signal generators, etc.
DIP20 package [4] DIP6 package [5]
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Single In-Line Package (SIP)
A single row of leads protruding from the bottom of its body.
SIP's are often used in packaging:• networks of multiple resistors• single on chip amplifier solutions• voltage regulators
Power controller in SIP package [6]
Audio power amplifier in SIP package [7]
Resistor network in SIP package [8]
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TSOP with Gull Wings
• Low profile• Tight lead spacing• High pin count• Used for surface mount
TSOPs are often used in packaging memory modules (SRAM, Flash memory, FSRAM and E2PROM)
SDRAM [9] DRAM [10]
TSOP - Thin Small Outline PackageGull Wings – shape of the pins
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QFP with Gull Wing andSurface Mount Leads
• QFP – Quad Flat Pack
• Socketing such packages is rare and through-hole mounting is not possible.
• Used for packaging memory, processors, controllers, ASIC, DSP, etc.
80‐pin Microprocessor in TQFP package [12]
TQFP ‐ Thermally Enhancedpackage [11]
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PLCC with J-Leads
• PLCC - Plastic Leaded Chip Carrier
• Used for surface mount
• Used for packaging memory, processors, controllers, ASIC, DSP
EEPROM from ALTERA [13]
PAL from TIin 28 pin package [14]
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Leadless Chip Carrier (LCC)
LCC from Tektronics [15]
• Used for packaging CMOS image sensors, MEMS,crystal oscillator filters, antenna switch modules
• Available in plastic and ceramic packaging
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Two main methods of ceramic packaging: • Refractory ceramic (used for high performance IC packaging)• Laminated ceramic (low cost approach used to create CerDIP package)
CPGA [16]
OpAmp from AD in CerDIP package for use in harsh environment [17]