Electronics Manufacturing Cell Phones

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Electronics ManufacturingCell Phones

• James Farrell
• Amanda Feather
• Ellie Heidingsfelder
• Kevin Kelly
• Scott Owens

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Overview

• James Farrell

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Basic Parts (Sony-Ericsson W300)
LCD screen
Camera/lens
Keypad
Microchips
PCBs
Plastic housing
Rechargeable battery
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General Process - Nokia

• Made entirely in-house
• 10 factories worldwide
• Make 325 million per year
• 10 per second
• Gross margin 33
• Best in industry

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Components

• 100 billion parts handled per year
• Almost all come from outside suppliers
• Factory for final assembly, integration, and test

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Circuit Boards

• Electrical components added to printed circuit
  board
• Parts loaded onto spindles with tape
• Feed into automated machines that pull parts off
  the tape
• Lays parts onto the printed circuit boards
• Boards baked for 7 minutes

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Testing

• Completed PCBs receive software
• Chips configured
• Tested for proper functionality

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Hand Work

• Remainder of parts installed by hand
• LCDs, cameras, casing, keypads, etc.
• Different for each customer

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Customization

• Handset put into cradle
• Given unique serial number
• Customer specific software downloaded into phone
• Custom menus, features, logos added
• Final testing
• Visual inspection and cleaning
• Phones shipped to wireless companies

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Printed Circuit Boards(PCB)

• Scott Owens

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What Are PCBs?

• A flat plastic or fiberglass board on which
  interconnected circuits and components are
  laminated or etched
• Chips and other electronic components are mounted
  on the circuits
• Single side circuitry printed on only one side
  of the board
• Double side circuitry printed on both sides of
  the board
• Multi-layered circuitry printed in combined
  layers (ideally used for communications)

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PCB Components

• The board made from nonconductive material
  (normally plastic)
• The circuitry made from conductive material
  (normally copper)

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PCB History

• 1930s first PCBs invented
• Invented by Dr. Paul Eisler, Australian Engineer
• Graduated from Vienna University 1930
• 1950-60s Single side PCBs dominated
• Mid 1960s-70s Double sided PCBs became industry
  standard
• Mid 1980s emergence of multi-layered PCBs

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Manufacturing Processes

• Drilling
• 1st Copper Plating
• Imaging (Photosensitive Resist)
• 2nd Copper Plating Tin/Lead Plating
• Resist removal
• Etching
• Tin/Lead Removal Solder masking (Polymer)
• Final plating (Electroless Nickel, Immersion
  Gold)

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Manufacturing Processes

• Overall process takes about 3 hours (advanced
  circuits)
• The process can vary depending on the
  manufacturer and design
• The following Process Map is from Morris
  Productions

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Microchips

• Ellie Heidingsfelder

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Manufacturing Steps

• Silicon conversion
• Wafer fabrication
• Final cleaning
• Etching
• Layering
• Ion implantation

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Silicon Conversion

• Raw silicon dioxide heated with wood and coke
• Produces MGS silicon
• MGS silicon is transformed into EGS silicon
• EGS is continuously tested until acceptable
  purity level is reached
• Large silicon ingot/cylinder is grown to be later
  processed into wafers
• Expose small seed of purified silicon to a molten
  batch of silicon (1500-2000C)
• Molten silicon attaches to purified silicon

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Wafer Fabrication

• Silicon ingot placed on a precision lathe to
  ensure size consistency
• Placed under X-ray observation to check for
  impurities
• Flat surface ground on one ingot side
• Water acts as lubricant
• Sliced into wafers with diamond wire saw
• Can be as thin as .020
• Wafers checked for consistency
• Damaged silicon removed by chemical etching using
  potassium hydroxide
• Wafers polished and shipped to wafer fabrication
  plant

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Wafer Fabrication Plant

• Silicon wafers converted from raw silicon to
  microchips
• Highly sterile environment
• On average one particle of contaminant in the air
  per square foot
• Typical hospital operating room has an average of
  10,000 times more contaminants in the air
• If only a few particles get onto wafer, it is
  ruined

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Final Cleaning

• Electronic film placed onto wafer
• Bathed in combination of chemical acids to remove
  any more contaminants (deposition)
• Insulating layer placed on silicon wafer
  (metallization)
• Microscopic pieces of metal placed over
  insulating layer
• Gas flows over the insulating layer to get rid of
  any impurities

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Etching

• Surface of wafer coated with photoresist
• Photolithography
• Mask placed over the wafer
• Ultraviolet light exposed to wafer
• Creates a gooey surface of photoresist
• Wafer dipped into a bath of developer to remove
  photoresist
• Pattern exposed
• Each chip has own unique pattern
• Wafer dipped into a chemical bath to expose
  silicon dioxide

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Layering

• Microprocessors have many unique layers
• Etching process continued by growing new silicon
  dioxide on top of old layers

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Ion Implantation

• Wafer exposed to a stream of ions through an ion
  implanter
• Ions alter the way the silicon conducts
  electricity throughout the chip
• Ions alter the surface properties of the
  semiconductor surface
• After ion implantation, atoms of metals placed
  between layers
• Creates electrical connections between layers
• Process repeated many times depending on
  complexity of microchip

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Manufacturing Steps
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Battery and LCD

• Kevin Kelly

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Cell Phone Battery

• Types
• Lithium-Ion (Li-Ion) Lithium Ion Polymer
• Nickel-Metal Hydride and Nickel-Cadmium
• Lead Acid
• Lithium ? Superior Energy Density
• Electrodes and Electrolytes
• Separated From Phone
• Vibrate

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Battery

• Two designs
• Prismatic
• Benefits due to packing efficiency
• Stronger casing needed to avoid bulging/swelling
• Cylindrical
• Sensitive
• Protect from moisture ? Dewpoint control
• 4 elements
• Lithium anode
• Metallic oxide cathode
• Dry solid polymer electrolyte
• Metallic current collector

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Battery Manufacturing

• 5kg Lithium stock extruded into sheet 250 microns
  thick
• Laminated ? further thinning to 20-40 microns
• Rolled up into separate cell sections
• Heated in vacuum oven 90 min at 80C
• Voltmeter and caliper used to check quality
• Metalizing of contacts ? spraying on molten metal
• Casing/insulating sleeve
• Injection molded plastics
• Insert moldings and overmolding
• Part of the battery outer casing for cell phone

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Tolerances

• Allow for alternative cells
• Allow for potential swelling (up to 10)
• 3 of voltage

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Cell Phone LCD

• OLEDs (Organic Light Emitting Diodes)
• Current causes it to become opaque
• Sandwiching liquid crystal between layers of
  plastic

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LCD Manufacturing Process

• Preparing the glass/plastic substrates
• Creating electrode pattern
• Coating with Indium Tim Oxide, Masking (Silk
  Screening)
• Etching
• Applying the polymer
• Coat with polymer
• Stroke in parallel fashion
• Sealing resin
• Plastic spacers
• Inject liquid crystal
• Polarizers
• Final assembly

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LCD

• Glass edge polishing units
• Glass substrate conveyor equipment
• LCD panel prober table units
• Lasers
• Silicon annealing (Excimer Lasers)
• Glass edge polishing

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Tolerances

• Testing electrical characteristics
• LCD panel prober table units
• Quality control
• Clean rooms
• AMLCDs 50 rejection rate
• Tight dimensional tolerances
• Philips ? zero tolerance (manufacturing process
  defects)
• Zero bright dot policy in 2001

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Plastic Technologies and Recycling

• Amanda Feather

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Plastic Technologies

• Crude Oil Natural Gas Chemicals Plastics
• Active Disassembly Research Ltd.
• Heated 60-150C (40-302F) to activate
• Memory plastics and metals used during
  manufacture to activate memory state
• Completely reversible so that disassembly is
  cheap and fast

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Plastic Parts

• Screws
• Hot Melt Adhesives

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Metal Parts

• Metals used are Martensite and Austenite
• Same as in eye glasses with Flexon frames
• Metal rivets, zippers, pushing ribbons

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Hazardous Materials

• EPA and Basel Action Network classify cell phones
  as hazardous waste
• When thrown into landfills, dangerous materials
  seep into ground and water
• Lead
• Affects brain, nervous system, and circulatory
  system
• Mercury
• Causes brain damage
• Cadmium
• Carcinogenic and acutely toxic
• Arsenic
• Carcinogen and causes multiple organ failure

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End of life

• Constantly updating technology leads to high
  turnover
• Phones used for average of 18 months
• Estimated 750 million cell phones currently in
  waste stream or in peoples drawers
• 130 million phones discarded yearly, resulting in
  about 65,000 tons of waste
• Only 625,000 recycled yearly, less than 1 percent
• Numerous organizations accept used cell phones
  for recycling and reuse

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Questions?