me 482 - manufacturing systems electronics manufacturing by ed red electronics manufacturing...

ME 482 - Manufacturing SystemsME 482 - Manufacturing Systems

Electronics Electronics ManufacturingManufacturing

ByBy Ed RedEd Red

EElectronics manufacturing comprises 1/3 of all lectronics manufacturing comprises 1/3 of all manufacturing in the world!manufacturing in the world!


ObjectivesObjectives

• Review basic processes used to make IC’s.Review basic processes used to make IC’s.

• Review basic processes used to make circuit boards.Review basic processes used to make circuit boards.

• Review methods and equipment used to assemble circuit Review methods and equipment used to assemble circuit

boards.boards.


IC production overviewIC production overview

The process begins by producing from The process begins by producing from quartzite (SiO2) an electronic-grade silicon quartzite (SiO2) an electronic-grade silicon (EGS) with little impurity. The process (EGS) with little impurity. The process involves mixing of elements into a furnace, involves mixing of elements into a furnace, grinding of the resulting alloy, and further grinding of the resulting alloy, and further chemical reaction with the powder to produce chemical reaction with the powder to produce the pure silicon. the pure silicon.

The process begins by producing from The process begins by producing from quartzite (SiO2) an electronic-grade silicon quartzite (SiO2) an electronic-grade silicon (EGS) with little impurity. The process (EGS) with little impurity. The process involves mixing of elements into a furnace, involves mixing of elements into a furnace, grinding of the resulting alloy, and further grinding of the resulting alloy, and further chemical reaction with the powder to produce chemical reaction with the powder to produce the pure silicon. the pure silicon.

A crystal growing A crystal growing process is used to process is used to grow single crystal grow single crystal ingots of silicon of ingots of silicon of diameters diameters approaching 12 approaching 12 inches and lengths to inches and lengths to 10 ft.10 ft.

A crystal growing A crystal growing process is used to process is used to grow single crystal grow single crystal ingots of silicon of ingots of silicon of diameters diameters approaching 12 approaching 12 inches and lengths to inches and lengths to 10 ft.10 ft.

An ingot is sliced into An ingot is sliced into wafers of thickness wafers of thickness about 0.02 inches, about 0.02 inches, followed by polishing followed by polishing and edge rounding.and edge rounding.

An ingot is sliced into An ingot is sliced into wafers of thickness wafers of thickness about 0.02 inches, about 0.02 inches, followed by polishing followed by polishing and edge rounding.and edge rounding.

IC production process is IC production process is a planar process a planar process consisting of region-consisting of region-specific layering or de-specific layering or de-layering processes to layering processes to constitute the many constitute the many microscopic electronic microscopic electronic devices spread across devices spread across the wafer surface.the wafer surface.

IC production process is IC production process is a planar process a planar process consisting of region-consisting of region-specific layering or de-specific layering or de-layering processes to layering processes to constitute the many constitute the many microscopic electronic microscopic electronic devices spread across devices spread across the wafer surface.the wafer surface.

Procedures are repeated Procedures are repeated until you build the until you build the desired integrated desired integrated circuit features that you circuit features that you want..these are called want..these are called dies.dies.

Procedures are repeated Procedures are repeated until you build the until you build the desired integrated desired integrated circuit features that you circuit features that you want..these are called want..these are called dies.dies.

Transfer of the IC to an Transfer of the IC to an electronics component is electronics component is called called packagingpackaging..

Transfer of the IC to an Transfer of the IC to an electronics component is electronics component is called called packagingpackaging..


IC packagingIC packaging

An IC is comprised of millions An IC is comprised of millions of electronic devices such as of electronic devices such as diodes, resistors, and diodes, resistors, and transistors, and is packaged in transistors, and is packaged in a plastic enclosed body as a a plastic enclosed body as a through hole or surface mount through hole or surface mount device with leads (legs) for device with leads (legs) for electrical interfacing to circuit electrical interfacing to circuit

boards.boards.

Through hole

Surface mount

Two materials are typically used to encapsulate the IC: Two materials are typically used to encapsulate the IC: 1) plastics with no hermetic sealing; and 2) ceramics with 1) plastics with no hermetic sealing; and 2) ceramics with hermetic sealing (e.g., alumina, Alhermetic sealing (e.g., alumina, Al22OO33).).


IC packagingIC packagingThe number of I/O terminals is a The number of I/O terminals is a function of the number of devices function of the number of devices on the IC. The dependency between on the IC. The dependency between the two is established by Rent’s the two is established by Rent’s Rule (around 1960):Rule (around 1960):

nnioio = C n = C nccmm

where nwhere nioio is the number of I/O leads is the number of I/O leads

and nand nc c is the number of circuits on is the number of circuits on

the IC, usually taken as the the IC, usually taken as the number of logic gates. Some number of logic gates. Some common values for C and m are:common values for C and m are: Microprocessor C = 4.5Microprocessor C = 4.5 m = 0.5m = 0.5 Static memory C = 6.0Static memory C = 6.0 m = 0.12m = 0.12

Lead spacing is about 20

mils


IC etchIC etch

Photolithographic process applied to a silicon wafer:(1) prepare surface; (2) apply photoresist; (3) soft bake; (4) align mask and expose; (5) develop resist; (6) hard bake; (7) etch; (8) strip resist.


IC MOSFETMOSFET


IC fabIC fab

IC fabrication sequence: (1) SiIC fabrication sequence: (1) Si33NN44 mask is deposited by CVD on Si substrate; (2) SiO mask is deposited by CVD on Si substrate; (2) SiO22

is grown by thermal oxidation in unmasked regions; (3) the Siis grown by thermal oxidation in unmasked regions; (3) the Si33NN44 mask is stripped; (4) mask is stripped; (4)

a thin layer ofa thin layer of SiOSiO22 is grown by thermal oxidation; (5) polysilicon is deposited by CVD is grown by thermal oxidation; (5) polysilicon is deposited by CVD

and doped and doped n+ n+ using ionusing ion implantation; (6) the polysilicon is selectively etched using implantation; (6) the polysilicon is selectively etched using photolithography to define the gate electrode; (7) source and drain regions are formed photolithography to define the gate electrode; (7) source and drain regions are formed by doping by doping n+ n+ in the substrate; and (8) P-glass is deposited onto the surface for in the substrate; and (8) P-glass is deposited onto the surface for protection.protection.


IC waferIC wafer

This 8-inch "wafer" of This 8-inch "wafer" of silicon contains 212 silicon contains 212 MediaGX™ processors MediaGX™ processors produced on the 0.35 produced on the 0.35 micron production line. micron production line. (For comparison, a human (For comparison, a human hair is 50 to 70 microns hair is 50 to 70 microns wide.) (Photo courtesy of wide.) (Photo courtesy of National Semiconductor)National Semiconductor)


IC manufacturingIC manufacturing

Photo Photo micrography micrography captures intricate captures intricate circuit lines circuit lines hundreds of times hundreds of times smaller than a smaller than a human hair.human hair. (Photo courtesy of (Photo courtesy of National National Semiconductor)Semiconductor)


IC manufacturing

Another micrograph Another micrograph photo.photo. (Photo courtesy (Photo courtesy of National of National Semiconductor)Semiconductor)



A manufacturing A manufacturing associate wears a associate wears a "bunnysuit" "bunnysuit" while handling while handling wafers at this wafers at this 1200-degree 1200-degree Centigrade Centigrade furnace.furnace. (Photo (Photo courtesy of courtesy of National National Semiconductor)Semiconductor)



At National At National Semiconductor's Semiconductor's wafer fabrication wafer fabrication plant in Arlington, plant in Arlington, Texas, many Texas, many manufacturing manufacturing processes are processes are computerized.computerized. (Photo courtesy of (Photo courtesy of National National Semiconductor)Semiconductor)



National's wafer fabrication facility in South Portland, Maine, National's wafer fabrication facility in South Portland, Maine, houses the latest sub-micron manufacturing equipment. houses the latest sub-micron manufacturing equipment. Containers in foreground, called pods, protect wafers from dust Containers in foreground, called pods, protect wafers from dust particles.particles. (Photo courtesy of National Semiconductor)(Photo courtesy of National Semiconductor)

A common clean room requirement of A common clean room requirement of 100 implies that no more than 100 100 implies that no more than 100 particles of size 0.5 particles of size 0.5 m or greater can m or greater can exist in 1 ftexist in 1 ft33..



National National Semiconductor's Semiconductor's new micro SMD new micro SMD packaging enable packaging enable dramatically dramatically smaller printed-smaller printed-circuit boards. circuit boards. Because micro Because micro SMD packages SMD packages are smaller than are smaller than chip capacitors, chip capacitors, they look like they look like mere dots on the mere dots on the smaller board.smaller board. ((Photo courtesy of National Photo courtesy of National Semiconductor)Semiconductor)



Until the release of the micro SMD package, a semiconductor device's die has always been much smaller than its package. With micro SMD, packaging can get no smaller because "The die IS the package!“(Photo courtesy of National Semiconductor)



Last year, National Last year, National Semiconductor Semiconductor introduced the world’s introduced the world’s smallest dual op amp, smallest dual op amp, the LMC6035. Now a the LMC6035. Now a portfolio of products portfolio of products are available in this are available in this package -- a package package -- a package so small that several so small that several devices fit on the head devices fit on the head of a pushpin with room of a pushpin with room to spare.to spare. ((Photo courtesy of Photo courtesy of National Semiconductor)National Semiconductor)



National National Semiconductor's Semiconductor's new four-, five-, new four-, five-, and eight-bump and eight-bump micro SMD micro SMD packages comply packages comply with a JEDEC with a JEDEC standard. The chip-standard. The chip-scale packages' scale packages' solder-bump pitch solder-bump pitch is 5 mm. is 5 mm. ((Photo courtesy of Photo courtesy of National Semiconductor)National Semiconductor)


IC yieldsIC yields

The IC manufacturing process consists of many steps. The

probability of good yield can be computed from

Y = Yc Ys Yw Ym Yt

where Yi is the yield at each step.

Typical yield values are

Crystal (Yc ) – 50%

Wafer slicing (Ys ) – 50%

Wafer yield/processing (Yw ) – 70%

Wafer multi-probe testing (Ym ) – 10% - 90%

Wafer full testing (Yt ) – 90%

Y = (0.5)(0.5)(0.7)(0.5)(0.9) = 0.08 (< 10%)Y = (0.5)(0.5)(0.7)(0.5)(0.9) = 0.08 (< 10%)


Circuit boardsCircuit boards

The printed circuit board (PCB) is a laminated The printed circuit board (PCB) is a laminated medium for mounting and interfacing electronic medium for mounting and interfacing electronic components, thus providing for their electrical components, thus providing for their electrical connection.connection.

The layers are made of copper foil conducting layers The layers are made of copper foil conducting layers interspersed with insulating layers made of polymer interspersed with insulating layers made of polymer composites reinforced with glass or paper fabrics. composites reinforced with glass or paper fabrics. Copper foil thickness is around 0.0015 in, while the Copper foil thickness is around 0.0015 in, while the insulation layer ranges from 0.031 in. to 0.125 in. Single insulation layer ranges from 0.031 in. to 0.125 in. Single and double-sided boards are produced in quantity and and double-sided boards are produced in quantity and then laminated to make multi-layer boards in a fairly then laminated to make multi-layer boards in a fairly complex process, since via holes are needed to complex process, since via holes are needed to electrically connect the different layers.electrically connect the different layers.

copper foil

insulatorinsulator


Circuit boards – prep stepsCircuit boards – prep steps

1. Board preparation1. Board preparation – shearing to create the proper board profile, hole – shearing to create the proper board profile, hole making to create tooling holes, and shaping operations to create tabs, making to create tooling holes, and shaping operations to create tabs, slots and other features. These phases are followed with bar-coding and slots and other features. These phases are followed with bar-coding and board cleaning.board cleaning.

2. Hole drilling2. Hole drilling – Circuit holes are drilled or punched to create – Circuit holes are drilled or punched to create insertion insertion holesholes or or via holesvia holes. Since the drill bit is usually small (< 0.05”) and . Since the drill bit is usually small (< 0.05”) and required to pass through different layers having different properties, required to pass through different layers having different properties, the drill speed is usually very high (100,000 rpm) and thus requires the drill speed is usually very high (100,000 rpm) and thus requires special drill motors/spindles.special drill motors/spindles.


Circuit boards – prep stepsCircuit boards – prep steps 3. Circuit pattern imaging and etching3. Circuit pattern imaging and etching – uses either of two methods – – uses either of two methods – screen printing (tracks > 0.01 in.) or photolithography (tracks < 0.01 screen printing (tracks > 0.01 in.) or photolithography (tracks < 0.01 in.) – to create the tracks and land of the circuit. The photolithography in.) – to create the tracks and land of the circuit. The photolithography method is similar to that used in IC production. The only difference is method is similar to that used in IC production. The only difference is that the photoresist covers portions of the copper layer and chemical that the photoresist covers portions of the copper layer and chemical etching is used to remove the exposed copper.etching is used to remove the exposed copper.

4. Plating4. Plating – used to plate the holes to provide a conductive path. Uses – used to plate the holes to provide a conductive path. Uses either electroplating or electroless plating methods.either electroplating or electroless plating methods.

5. Cleaning/inspection5. Cleaning/inspection - finished boards are usually cleaned, inspected - finished boards are usually cleaned, inspected and tested to complete the process. Visual inspection is used to find and tested to complete the process. Visual inspection is used to find obvious flaws, while continuity testing is used to find more subtle obvious flaws, while continuity testing is used to find more subtle problems, particularly in multi-layer boards. Finally, the board tracks problems, particularly in multi-layer boards. Finally, the board tracks and land surfaces are coated with solder to protect the copper.and land surfaces are coated with solder to protect the copper.


Electronics assemblyElectronics assembly Modern assembly plants use automatic insertion machines, Modern assembly plants use automatic insertion machines, and sometimes robots for non-standard parts.and sometimes robots for non-standard parts.

The Fuji CP-643E combines high-speed placing with an innovative new PCB loading The Fuji CP-643E combines high-speed placing with an innovative new PCB loading system to increase throughput. The machine achieves a placing speed of 0.09 sec/shot and system to increase throughput. The machine achieves a placing speed of 0.09 sec/shot and can be loaded with up to 140 part types. can be loaded with up to 140 part types.


Electronics assembly: Electronics assembly: control technologiescontrol technologies

Critical to advanced electronics manufacturing are:Critical to advanced electronics manufacturing are:

• Vision processes for part inspection, and rigid-body Vision processes for part inspection, and rigid-body

offsets for precision assemblyoffsets for precision assembly

• Motion and I/O control, using asynchronous architecturesMotion and I/O control, using asynchronous architectures

• Mechanism and tooling design and calibration Mechanism and tooling design and calibration


Machine visionMachine vision

Vision is used for testing/inspection, feature finding, and rigid-body Vision is used for testing/inspection, feature finding, and rigid-body correction. correction.

Mechanisms and their end-effectors (vacuum grippers, Mechanisms and their end-effectors (vacuum grippers, finger grippers, etc.) must move to parts that will be finger grippers, etc.) must move to parts that will be deposited on the IC boards, then pick them up, move to the deposited on the IC boards, then pick them up, move to the circuit board pad location, then deposit the part. The circuit board pad location, then deposit the part. The accuracy requirements can be in the thousandths of inches accuracy requirements can be in the thousandths of inches or less. The accuracy will depend on the lead pitch or less. The accuracy will depend on the lead pitch requirements(moving to 0.15 mm).requirements(moving to 0.15 mm).


Machine visionMachine vision

Vision is used for testing/inspection, feature finding, and rigid-body Vision is used for testing/inspection, feature finding, and rigid-body correction. correction.

Because of errors in part presentation and the part picking, Because of errors in part presentation and the part picking, it is required that vision systems view these parts relative to it is required that vision systems view these parts relative to the tool before placement to correct for part picking rigid-the tool before placement to correct for part picking rigid-body errors (offsets) in both position and orientation. body errors (offsets) in both position and orientation. Similar errors exist for the placement of the circuit board on Similar errors exist for the placement of the circuit board on the board holder. the board holder.


Example - asynchronous control methodExample - asynchronous control method

Process 1 (Tool process)Process 1 (Tool process) Process 2 (Vision process)Process 2 (Vision process)

Pick up partPick up part while(1): while(1):

Move part under cameraMove part under camera Wait until signal5 == Part_there Wait until signal5 == Part_there

Set signal5 to Part_thereSet signal5 to Part_there Take picture and load offsets Take picture and load offsets

Wait until signal93 == Vsn_DoneWait until signal93 == Vsn_Done Set signal93 = Vsn_Done Set signal93 = Vsn_Done

Read offsets and adjust targetRead offsets and adjust target Set signal5 = Part_not_there Set signal5 = Part_not_there

Control Control process 2process 2

Control Control process 1process 1

ServerServer


Electronics assemblyElectronics assembly

Assembly considerations:Assembly considerations:

• Use control programs.Use control programs.

• Move components from reel feeders to the board.Move components from reel feeders to the board.

• Insert components through holes or surface mount them.Insert components through holes or surface mount them.

• Through hole assembly: Through hole assembly:

- pre-form the leads. - pre-form the leads.

- insert leads into holes. - insert leads into holes.

- crop or clinch leads on the other side of the board. - crop or clinch leads on the other side of the board.

- wave solder the board undersides. - wave solder the board undersides.


Electronics assemblyElectronics assembly

Assembly considerations:Assembly considerations:

• Surface mounted component:Surface mounted component:

- rely on calibration procedures and sensor measurement. - rely on calibration procedures and sensor measurement.

- place and orient the leads on mounting pads (land). - place and orient the leads on mounting pads (land).

- screening used to place solder paste onto the pads - screening used to place solder paste onto the pads

- boards passed through oven to “reflow” solder - boards passed through oven to “reflow” solder


Electronics board testingElectronics board testing (after cleaning)(after cleaning)

Testing methods:Testing methods:

• InspectionInspection

• Vision systemsVision systems

• Functional testing ( tested by energizing circuits)Functional testing ( tested by energizing circuits)

• Burn-in testBurn-in test to verify full functionality for a given period of to verify full functionality for a given period of

time time

If the board fails any of these tests, then rework is often used to try to If the board fails any of these tests, then rework is often used to try to recover the board.recover the board.


Electronics assembly videosElectronics assembly videos

We will now see videos on We will now see videos on circuit board assembly. circuit board assembly. Be sure Be sure to take notes because you will be to take notes because you will be

tested on the video material!tested on the video material!


Reference Reference - “Electronic Manufacturing and Packaging in - “Electronic Manufacturing and Packaging in Japan,” Michael J. Kelly, Chair William R. Boulton, Editor, Japan,” Michael J. Kelly, Chair William R. Boulton, Editor, John A. Kukowski, Eugene S. Meieran, Michael Pecht, John John A. Kukowski, Eugene S. Meieran, Michael Pecht, John W. Peeples, Rao R. Tummala, JTEC (Japanese Technology W. Peeples, Rao R. Tummala, JTEC (Japanese Technology Evaluation Center) Panel Report, February, 1995Evaluation Center) Panel Report, February, 1995

Note: Note: See report link on class websiteSee report link on class website

The state of electronics The state of electronics manufacturing in the U. S.manufacturing in the U. S.


Report conclusions:Report conclusions:

• Japan leads the United States in almost every Japan leads the United States in almost every electronics packaging technology.electronics packaging technology.

• Japan clearly has achieved a strategic advantage in Japan clearly has achieved a strategic advantage in electronics production and process technologies. electronics production and process technologies.

• Japan has established this marked competitive Japan has established this marked competitive advantage in electronics as a consequence of advantage in electronics as a consequence of developing low-cost, high-volume consumer products.developing low-cost, high-volume consumer products.

The stateThe state



• Japan's infrastructure, and the remarkable cohesiveness of Japan's infrastructure, and the remarkable cohesiveness of vision and purpose in government and industry, are key vision and purpose in government and industry, are key factors in the Japan’s success.factors in the Japan’s success.

• Although Japan will continue to dominate consumer Although Japan will continue to dominate consumer electronics in the foreseeable future, opportunities exist for electronics in the foreseeable future, opportunities exist for the United States and other industrial countries to capture the United States and other industrial countries to capture an increasingly larger share of the market.an increasingly larger share of the market.

• The JTEC panel identified no insurmountable barriers The JTEC panel identified no insurmountable barriers that would prevent the United States from regaining a that would prevent the United States from regaining a significant share of the consumer electronics market.significant share of the consumer electronics market.

The stateThe state



““The Japanese can do it; Americans can do it. The The Japanese can do it; Americans can do it. The issue that separates the United States from Japan issue that separates the United States from Japan in high-volume, low-cost electronic assembly is in high-volume, low-cost electronic assembly is neither technology nor manufacturing; it is neither technology nor manufacturing; it is primarily the will to take the measures necessary primarily the will to take the measures necessary to compete and succeed.”to compete and succeed.”

Electronics manufacturingElectronics manufacturing


What have we learned?What have we learned?

Electronics manufacturingElectronics manufacturing

me 482 - manufacturing systems electronics manufacturing by ed red electronics manufacturing...

Documents

ic production process

circuit boards

review basic processes

microprocessor c

doped n

number of devices

static memory c

review methods