1905.2013electronic pack….. summary slide 1 summary: fys 4260 microsystems and electronic...

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1905.2013 Electronic Pack….. Summary Slide 1

Summary: FYS 4260 Microsystems and Electronic Components, Packaging and Production

(Updated May 23th, 2013)

The course material was developed in INSIGTH II, a project sponsored by the Leonardo da Vinci program of the European Union

Electronic Pack….. Summary Slide 2

Compulsory Project

• The Compulsory Projects were graded and will count 20%

• Compulsory means compulsory – project report must be submitted and oral presentation must be given, and grading A, B,C,D or E necessary for final exam admission.

• SMD Circuit Design, Production and Testing are important for the course and should be understood and learned

– Questions usually given to check that all students in each group have worked with the project and understood and learned issues covered.

Electronic Pack….. Summary Slide 3

Chapter 1 Introduction: Electronic products, technologies and packaging

• Definition of ELECTRONIC PACKAGING:–"The realization of the physical, electronic system, starting with block-/circuit diagram”

• Involves choice of technology for implementation, choice of materials, detailed design in chosen technology, analysis of electrical and thermal properties, reliability.

• This definition is one among many, and may shift as the field is further developed.

Electronic Pack….. Summary Slide 4

Multidisciplinary

• Requires combination of many disciplines:

–Electronics–Materials properties and materials compatibility–Mechanics–Chemistry–Metallurgy–Production technology–Reliability, etc.

Electronic Pack….. Summary Slide 5

Development Phases

Product Development PhasesFeasibility Study Project Phase

Productidea

Productrecommend

-ation

Laboratorymodel

A-model B-model C-model

Fig. 1.1: Phases in the development of electronic systems.

Marketresearchideas

Pre-study

Specifi-cations

Develop-ment,mainprinciple

s

Detaileddesign

Pilotproduction,industrial-isation,marketing

Production,sales,service

Electronic Pack….. Summary Slide 6

LEVELS OF INTERCONNECTION

Fig 1.2 Levels of interconnections in large electronic systems

Electronic Pack….. Summary Slide 7

Chapter 2:

Technologies for Electronics - Overview

Electronic Pack….. Summary Slide 8

Fig. 2.1 Hole mounting (insertion-) technology printed circuit board

• Fig. 2.1: Hole mounting (insertion-) technology printed circuit board.

Electronic Pack….. Summary Slide 9

Fig. 2.2 Surface mount technology printed circuit board

• Fig. 2.2: Surface mount technology printed circuit board.

Electronic Pack….. Chapter 2 Slide 10

Advantages and Disadvantages of Surface Mount Technology (SMT)

• Fig. 2.3 Volumes of different kinds of components used 1980 – 94, and from 2002 to 2008

Electronic Pack….. Summary Slide 11

ADVANTAGES OF SMT• Space saving 50 % or more

–Efficient, highly automated production

Fig. 2.4 a): Size comparison of different package types with approximately the

same lead count which can be used for the same size of integrated circuit chip.

DIP

Chip Carrier

Die Cavity

Lead Count DIP Area : Chip Carrier Area18 2.7 : 124 4.5 : 140 5.2 : 164 5.6 : 1

Electronic Pack….. Summary Slide 12

Chip on Board, continued

Fig. 2.6: Chip connection by wire bonding, tape automated bonding (TAB) and flip chip, schematically.- Wire bonding (Chip and wire)- Tape Automated Bonding (TAB)- Flip chip

Comment: TAB not important part of Syllabus

Electronic Pack….. Summary Slide 13

Thick Film Hybrid Technology• High

temperature thick film:

–Screen printing of conducting, resistive and insulating materials in paste form onto ceramic substrate, in many layers.

Fig. 2.7: Thick film hybrid circuits.

Electronic Pack….. Summary Slide 14

Thin Film Hybrid technology, continued

(Fig. 2.9)

Fig. 2.9.a : Picture of a thin film hybrid circuit.

Electronic Pack….. Summary Slide 15

Multi-Chip Modules, continued • THE MAIN TYPES OF

MCMs–Multilayer ceramic

(MCM-C)• Many laminated thin

layers of alumina or other ceramic, with screen printed metallization between

• Fig. 2.12: With the multilayer ceramic module it is possible to combine hermetically sealed, wirebonded Si chips in a cavity with lid, soldered, surface mounted packaged chips, and soldered passive components.

Electronic Pack….. Summary Slide 16

TECHNOLOGY TRENDS

• The development in semiconductor technology makes ever more advanced electronic systems possible. Some important trends for the systems development are:

– Smaller critical dimensions, i.e. line widths and distances on the IC and module/PCB.

– Increasing packaging density, i.e. more and more electric functions are possible to implement in a given area or volume

– Increasing maximum operating frequency/bit rate

– Increasing power dissipated per unit area and -volume

– Increased possibility to realise complex circuit functions with standard hardware by programming software

– Ever lower price per electrical function

Electronic Pack….. Summary Slide 17

Technology Trends, continued

• The established technology cannot satisfy the needs and requirements, and new technology always appears. It seems as if we hit physical limits on many fronts.

• However, earlier, when such limits have appeared, new ideas and new principles have been found.

• This will probably also happen in the future and will make the field of microelectronics dynamic and exciting in the future, for scientists as well as for users.

Electronic Pack….. Summary Slide 18

Chapter 3 Materials and Basic processes

Electronic Pack….. Summary Slide 19

Material properties

• Table 3.1 shown below: Remembering data that can be easily found on Internet not important to memorise any longer!

• However, distinguese semiquantitave properties like that metals in general have higher thermal conductivity than polymers should be remembered.

Table 3.1 a): Properties of some important materials in electronics: Conductors[3.1].

Melting PointElectricalResistivity

ThermalExp. Coeff.

ThermalConductivity

Metal/Conductor [°C] [10-8Ohmm] [10-7/°C] [W/m.°K]Copper 1083 1.7 170 393Silver 960 1.6 197 418Gold 1063 2.2 142 297Tungsten 3415 5.5 45 200Molybdenum 2625 5.2 50 146Platinum 1774 10.6 90 71Palladium 1552 10.8 110 70Nickel 1455 6.8 133 92Chromium 1900 20 63 66Invar 1500 46 15 11Kovar 1450 50 53 17Silver-Palladium 1145 20 140 150Gold-Platinum 1350 30 100 130Aluminium 660 4.3 230 240Au-20%Sn 280 16 159 57Pb-5%Sn 310 19 290 63Cu-W(20%Cu) 1083 2.5 70 248Cu-Mo(20%Cu) 1083 2.4 72 197

Electronic Pack….. Summary Slide 20

Polymers (Plastics)

• Composition, properties:–Linear, branched or crosslinked

Electronic Pack….. Summary Slide 21

Plastics, continued

–"Glass transition": change from glass-like to rubber - like

Electronic Pack….. Summary Slide 22

Inorganic materials: Ceramics

• Non-metallic materials processed in high temperature reactions (>600 °C)–Electrical insulator

–Powder method:• Powder is mixed with binder and

pressed in a mould.

• During subsequent heat treatment (sintering) the binder evaporates and the materials are partly melted together

• Considerably shrinkage during sintering (15-20%)

Electronic Pack….. Summary Slide 23

Photolithography

• Fig. 3.10:The steps in photolithographic transfer of patterns and the subsequent etching of metal films with negative photoresist. If positive resist is used, it is the illuminated part of the photoresist, which is removed during the development.

Electronic Pack….. Summary Slide 24

ScreenPrinting and Stencil Printing

• Fig. 3.11: Screen printing: a) and b): Printing process, c) and d): Details of

the screen

Electronic Pack….. Summary Slide 25

Methods for Electrical and Mechanical Contact

• Soldering–Wetting: (Fig. 3.14)

Young´s eq.: lsl cos s

Bluetooth trancieverEricsson

Electronic Pack….. Summary Slide 26

Soldering: Lead free solder

• Transition to lead-free solder after the use of lead in electronics was heavily restricted by EU in 2006

• Tin-silver-copper (SAC) alloys are most commonly used for lead free soldering

• Sn - 3.0Ag 0.5 - Cu = SAC 305• Higher processing temperature

compared to lead based solder– 240 - 260°C

– Less experience and reliability data available

RoHS: Restriction of the use of certain Hazardous Substances in electrical and electronic equipment

Tin whiskers: Occurs on components plated with pure Tin. Have also been observed on SAC coated surfaces.

Electronic Pack….. Summary Slide 27

Electrical interconnect: Ball Grid Array (BGA)

• Can combine flip-chip and BGA package

• Easier to mount on PCB than direct flip-chip

• Flexibility

• CABGA = Chip Array - Ball Grid Array

Electronic Pack….. Summary Slide 28

Electrical interconnect: Miniaturization• Increasing demand for miniaturization

– Tape Automated Bonding

– Chip on board (multichipmodul MCM)

– Ball grid array (BGA)/ Chip scale package (CSP)

– Flip chip

Electronic Pack….. Summary Slide 29

Chapter 4 Components for Electronic Systems

• Description of geometrical, thermal and some electrical properties of main types of components. No description of electrical properties of monolithic circuits.

Electronic Pack….. Summary Slide 30

Surface Mounted Resistors

• Fig.4.2.a: Thick film layers on ceramic substrate, rectangular shape

Electronic Pack….. Chapter 4 Components for Electronic Systems Slide 31

Capacitors• Multilayer Ceramic Capacitors

Fig. 4.7.a: SMD Multilayer Ceramic Capacitor

Fig. 4.7.b: Metal system for the endtermination of multilayer ceramic capacitors.

Electronic Pack….. Summary Slide 32

Capacitors, continued• Fig.4.3: Electrical equivalent

model for capacitor. If Rp can be neglected the impedance is given by:

| Z | = [Rs2 + (L - 1/C)2]1/2

• Fig. 4.4: The frequency dependence of impedance for multilayer ceramic capacitors (below) and tantalum electrolytic capacitors (top), all having 100 nF capacitance value.

Rp

L RsC

Electronic Pack….. Chapter 4 Components for Electronic Systems Slide 33

Capacitors, continued• Tantalum, Dry Electrolytic

– Very high capacitance, low voltages, low leakage current

http://www.nec-tokin.com

• Electrolytic Capacitors – why they are polarised:– The capacitance is the oxidised surface of the anode– Reversed polarity will remove the oxide by reduxtion reaction

Electronic Pack….. Summary Slide 34

SMD IC Packages

Fig. 4.19: Surface mounted SO (Small Outline) IC package (Philips).

Electronic Pack….. Summary Slide 35

High Performance Packages

Fig. 4.27: Thermal via-holes in the printed circuit board, for better heat conduction.

Electronic Pack….. Summary Slide 36

Electrostatic Discharges - Component Damages and Precautions

Fig. 4.33: MOS transistor schematically. The gate oxide is very vulnerable for damage by electrostatic discharge. Gate oxides

down towards 10Å are used today (2012).

Electronic Pack….. Summary Slide 37

Chapter 5: Printed Wiring Boards

Electronic Pack….. Summary Slide 38

Substrate

• The purpose of the substrate for electronic component mounting is:–Mechanical support

–Electrical interconnection

–Heat conduction

Electronic Pack….. Summary Slide 39

Printed Wiring Boards, continued

Fig. 5.2: Printed wiring board structures with varying complexity: a) Single sided and double sided.b) Double sided through hole plated with bare Cu or Sn/Pb surface.c) Four layer board.d) Six layer board with two Cu/Invar/Cu cores.

Electronic Pack….. Summary Slide 40

New Materials for PWBs• Higher Tg• Better dimensional stability

• r low, not dependent on T, f, or moisture

• Low losses• Lower TCE • Purpose

– High frequency use– Controlled characteristic impedance– High reliability

• Materials– Cyanate ester– PTFE (Teflon)– Polyimide– and others

Electronic Pack….. Summary Slide 41

Special Boards• Flexible printed wiring boards

–Dynamic or static bending.–Uses: Movable parts and odd shaped, cramped places

Electronic Pack….. Summary Slide 42

Chapter 6: Printed Circuit Board Design

• Example of a Printed Circuit Board

Electronic Pack….. Summary Slide 43

PCB Design, continued

• Advanced PCB CAD tools a neccessity–Schematics–Component Library–Critical Parameters (Placement Constraints, Electromagnetic Compatibility, Thermal Limitations, etc)

–Automatic Routing–Final Touch Manual Routing–(Verification by Final Simulation and Back Annotation)

Electronic Pack….. Summary Slide 44

Important Aspects of Design, continued

Fig. 6.9: Via holes should be separated from solder lands.

Electronic Pack….. Summary Slide 45

Solder Land Dimensions, continued

Fig. 6.13: Additional dimensions of SMD component and solder lands. Width a: a = Wmax + K Length b: * Reflow : b = Hmax + 2Tmax + K * Wave: b = Hmax + 2Tmax + 2K Length B: B = Lmax + 2Hmax + 2Tmax + K, K = 0.25 mm.

Electronic Pack….. Summary Slide 46

Design for Testability

Fig. 6.18: a): Correct position of test point, separated from solder land. b): Test points on solder lands are not recommended. c): Testing on components or component leads should be avoided.

Electronic Pack….. Summary Slide 47

Thermal Design, continued

• Thermal Resistance–Rjc: Thermal resistance junction - case

–Rjl: Thermal resistance junction - lead

–Rja: Thermal resistance junction - ambient

• Tj = Ta + P x Rja

–Ta: Ambient temperature

–Tj : Junction temperature

Fig. 6.23: Thermal model of an IC and package.

Electronic Pack….. Summary Slide 48

High Frequency Design

• When needed?–tr < 2.5 tf

–tr = 10 - 90 % rise time

–tf = l/v

• tr is 10-90% rise time

• tf is time-of-flight-delay over the length l of critical conductor paths of the circuit

• v is propagation speed: v = c/r

– c speed of light

– r effective relative dielectric constant

Electronic Pack….. Summary Slide 49

High Frequency Design, continued

Fig. 6.34:Distorted signal as a function of time when the transmitter has 78 ohms impedance and the receiver has different impedances as indicated. If the receiver also has 78 ohms impedance the signal at the receiver is a time delayed replica of the transmitted signal.

Electronic Pack….. Summary Slide 50

High Frequency Design, continued

Fig. 6.35: Geometries for obtaining a controlled characteristic impedance.

Electronic Pack….. Summary Slide 51

Design of Flexible Printed Circuits, continued

Fig. 6.43: a): Solder lands on flexible prints should be rounded in order to reduce the possibility for failures, b): The contour of the board should be rounded in order to reduce possibilities for tearing (dimensions in inches). The "rabbit ears" on the ends of the metal foil is for obtaining better adhesion to the polyimide. c): Plastic rivets should be used to avoid sharp bends in the interface between the flexible and the rigid parts of the PCB.

a)

b)

c)

Electronic Pack….. Summary Slide 52

Chapter 7:Production of Printed Circuit Boards

• Focus on automated production of printed circuits by Surface Mounting Technology (SMT) and Hole Mounting Technology (HMT).

Electronic Pack….. Summary Slide 53

Hole Mounting• Axial components:

Sequencing and mounting

• Radial components: Mounting

• DIP components: Mounting

• Odd components: Robot or

hand mounting

Axial Components

Sequencing

Lead forming

Insertion

Cut-and-clinch

Wave soldering

DIP

Insertion

Lead forming

Cut-and-clinch

Radial Components

Insertion

Hand mounting ofspecial components

Electrical test

To customer

Faulty boards

Visual inspection

Cleaning

Robot mounting/hand mountingof odd compomnents

Repair

Fig. 7.1:The process for production of hole mounted PCBs

Electronic Pack….. Summary Slide 54

Surface Mounting• Soldering by wave solder process or by reflow process Fig. 7.13: Application of adhesive for SMD mounting by:

a): Screen printing

b): Dispensing

c): Pin transfer

Electronic Pack….. Summary Slide 55

Surface Mounting, continued

Fig. 7.15: Double wave for SMD soldering. The first is a turbulent wave that wets, followed by a gentle “lambda wave” that removes superfluous solder.

Lambda wave

Electronic Pack….. Summary Slide 56

Reflow Solder Process

• Print solder paste

• Mount components

• Dry solder paste

• Solder by heating to melting of paste

Electronic Pack….. Summary Slide 57

Other Soldering Methods

• Impulse (hot bar-, thermode-) soldering

• Hot plate / hot band soldering (thick film hybrid)

• Hot air soldering

• Laser soldering

Electronic Pack….. Summary Slide 58

Component Placement

–Automatic, dedicated pick-and-place machines

–Manual placement (prototypes, repair)–Semi-manual (light guided table, etc.)

• Programmable robot• Elements of Pick-and-Place Machine

– Board magazine/feeder system– Mounting head(s) (with interchangable grip tools)– Programming/control unit– Component "storage" and feeder– (Vision system)

Electronic Pack….. Summary Slide 59

Solder faults

Fig. 7.38: Small SMDs standing on edge due to the "Manhattan-" or "tombstone-" effect.

Electronic Pack….. Summary Slide 60

Process Sequences

Fig. 7.44 a -d): Process sequences for boards with different types of components on the two sides.

The steps marked "For all processes" on figure a) are not repeated on the other figures.

Electronic Pack….. Summary Slide 61

Board Testing

• Functional test

• "In-circuit" test

• NB: Good designs use one-sided testing–Test jigs

Electronic Pack….. Summary Slide 62

Chapter 8: Hybrid Technology and Multichip Modules

• Hybrid = mixture, i. e.: Components and wiring integrated on the substrate

Electronic Pack….. Summary Slide 63

Types of Hybrids and Multichip Modules

• Thick film technology–High temperature thick film hybrid technology–Polymer thick film hybrid technology

• Thin film technology–Conventional thin film technology (one conductor

layer)–Multilayer thin film technology

• Multichip modules:–Multilayer ceramic (MCM-C) (C for ceramic)–Multilayer thin film (MCM-D) (D for deposited)–Multilayer fineline circuit boards (MCM-L) (L for

laminated) Please also confer to Chapter 5.

Electronic Pack….. Summary Slide 64

Production process, continued• Printing process

–Printing–Drying at 100 - 150 °C–Firing at 700 - 1000 °C

Fig 8.1: Typicaltemperature profilefor thick filmfiring.

Electronic Pack….. Summary Slide 65

Production process,

continued

Fig. 8.7: Process flow for mounting of thick film hybrid circuits based on: a): Naked ICs and gluing of discrete components.

Electronic Pack….. Summary Slide 66

Polymer Thick Film Technology• In polymer thick film

hybrid technology (PTF) conductors, resistors and insulating layers use a polymer matrix instead of glass matrix, and these are made in several layers on ordinary printed wiring board laminates, flexible substrates and injection moulded plastic materials that can serve as combined printed circuits and chassis.

Electronic Pack….. Summary Slide 67

Thin Film Technology

• Substrate materials–Alumina, glass, silicon

• Conductor materials–Gold, aluminium

• Resistor materials–NiCr (Chromnickel), Ta2N (Tantalnitrid)

• Insulation/dielectrics/passivation materials–SiO2 (Silicon dioxide), SiN3 (Silicon nitride), Al2O3 (Silicon nitride), Ta2O5 (Tantaloxide)

Electronic Pack….. Summary Slide 68

Multilayer Thin Film - MCM-D

• Process–1. Spinning polyimide insulation–2. Deposition Al metallization–3. Photolithography, wet etch –4. Spinning polyimide –5. Etching vias –6. Repetition steps 1 - 5 –7. Metallization and etching of metal

Electronic Pack….. Summary Slide 69

MCM-C, continued

Fig. 8.19: Production process for multilayer ceramic, schematically.

29.05.2007 Electronic Pack….. Summary Slide 70

Combination Technologies

•Multilayer thin film - on - multilayer ceramic

Fig. 8.24: High performance modules made in a combination of multilayer thin film and multi layer ceramic technology: a): NEC Corporation computer SX-3 using flop TAB carrier on thin film and alumina based substrate. b): IBM Enterprise System/9000 packaging hierarchy using flip chip, polyimide/copper thin film on 63 layers glass ceramic substrate.

a)

b)

Electronic Pack….. Summary Slide 71

Chapter 9:Micro Structure Technology and Micromachined

Devices

Picture shows the interior chip assembly of the SA30 Crash Sensor, a microsystem from SensoNor, Norway

Electronic Pack….. Summary Slide 72

Silicon Micromachining

• Three-dimensional structuring by anisotropic and selective etching of silicon: Example: 4mmx4mm silicon pressure sensor chip

Electronic Pack….. Summary Slide 73

The Top Ten Success Factors of Micromachined Devices

• 1. Batch organised planar processing technology

• 2. Microelectronics manufacturing infrastructure

• 3. Research results from solid state technology and other

related fields of microelectronics

• 4. Micromachining

• 5. Wafer and chip bonding

• 6. Mechanical material characteristics

• 7. Sensor effects

• 8. Actuator functions

• 9. Integrated electronics

• 10. Combination of features

Electronic Pack….. Summary Slide 74

The Bottom Ten List of Inhibiting factors

• 1. Slow market acceptance

• 2. Low production volumes

• 3. Immature industrial infrastructure

• 4. Poor reliability

• 5. Complex designs and processes

• 6. Immature processing technology

• 7. Immature packaging and interconnection technologies

• 8. Limited research resources

• 9. Limited human resources

• 10. High costs

Electronic Pack….. Summary Slide 75

Crystal Structure of Single Crystal Silicon

• It is a face-centered cubic structure (diamond structure) with two atoms associated with each lattice point of the unit cube. One atom is located in position with xyz coordinates (0, 0, 0), the other in position (a/4, a/4, a/4), a being the basic unit cell length.

Electronic Pack….. Summary Slide 76

Miller Indices for a Plane in a Crystal

The orientation of of different crystal planes in the basic unit cell can be described by the Miller indices (hkl) between parentheses with each plane defined by a vector description (hx + ky + lz) of the direction perpendicular to that plane. This is related to a coordinate system oriented in parallel with the side edges of the basic cell, with the Miller indices reduced to the smallest possible integers with the same ratio.

x y

z

3

2

2

1

1

12

Electronic Pack….. Summary Slide 77

Important Crystal Planes in the Silicon Crystal

•(100), (110) and (111) are the three most important crystal planes of the silicon crystal structure.

Electronic Pack….. Summary Slide 78

Silicon as a Mechanical Material

CharacteristicsSingle CrystalSilicon

Stainless SpringSteel Units

Ultimate Strength ca. 7,0*109 ca. 2,0*109 N/m2

Yield Strength ca. 7,0*109 ca. 1,0*109 N/m2

Young's Modulus of Elasticity ca. 1,7*1011 ca. 1,9*1011 N/m2

Shear Modulus ca. 6,2*1010 ca. 8,2*1010 N/m2

Knoop Hardness ca. 8,5*109 ca. 6,6*109 N/m2

Density 2,3*103 7,9*103 Kg/m3

Thermal Conductivity1,6*102 0,33*102 W/m°C

Thermal Expansion 3*10-6 12*10-6 m/m°C

Chemical ResistanceExcellent Fair

Corrosion ResistanceExcellent Fair

Bulk Micromachining in Silicon• Three-dimensional micromachining in single

crystal silicon by means of photolithography and etching techniques

79

Si waferSi waferThin filmThin filmPhotoresistPhotoresist

Deposition

Patterning

Etching

Etching of silicon

80

An Introduction to MEMs Engineering - Nadim Maluf and Kirt Williams

• Anisotropy - directionally dependent

• Isotropy - identical properties in all directions

Surface Micromachining

• A set of methods to make three-dimensional surface structures, with deposition of thin films as additive technique and selective etching of the deposited thin films as subtractive techniques.

• In practice, single crystal silicon wafer is the dominant substrate material, and chemical vapor deposited (CVD) polysilicon is mostly used as the material making up the three-dimensional surface structures.

81

www.mems-exchange.org

Electronic Pack….. Summary Slide 82

Understanding Anisotropic Underetching• Anisotropic underetching of mask openings

nonparallel with <110> direction, and anisotropic underetching of convex corners.

• (a) is a typical pyramidal pit, bounded by the (111) planes, etched into silicon with an anisotropic etch through a square hole in an oxide mask.

• (b) is a type of pit which is expected from anisotropic etch with a slow convex undercut rate.

• (c) is the same mask pattern resulting in an substantial degree of undercutting using an etchant with a fast undercut rate such as EDP.

• In (d), further etching of (c) produces a cantilever beam suspended over the pit.

• (e) is an illustration of the general rule for anisotropic etch undercutting assuming a "sufficiently long" etching time. The reader who understands (e) has understood the main principles.

Electronic Pack….. Summary Slide 83

Electrochemical Selective Etching of Silicon

• Low-doped material can be passivated, both p-type and n-type. This gives more processing flexibility, and low-doped silicon can be used as substrate material for integrated components such as piezoresistors.

• High accuracy of thickness of unetched layer can be achieved, typical ±1micrometer, by using well-controlled implantation and diffusion techniques for making the p-n- junction.

• This method makes KOH a useful selective etch, avoiding the health dangers of EDP-etch.

Electronic Pack….. Summary Slide 84

Surface Micromachining:Process Sequence Diagram

• Figure XIII.12 Process sequence for the fabrication of laterally mobile structures using surface micromachining and sacrificial layer technique.

Electronic Pack….. Summary Slide 85

Anodic Wafer Bonding –Schematic View

• Schematic view of silicon-to-silicon anodic bonding and silicon-to-glass anodic bonding.

Sputtered Pyrex Borosilicate Glass

Silicon

Pyrex Borosilicate GlassSilicon

Silicon

-100 - 1200V-50 - 200V T 400 °C T 400 °C

0V0V

Electronic Pack….. Summary Slide 86

Integration and Packaging

• Hybrid integration in surface mount transfer moulded epoxy package

Electronic Pack….. Summary Slide 87

Adhesives

• Understand the difference between adhesive and cohesive failure

Electronic Pack….. Summary Slide 88

Adhesives• Thermoset adhesives

– Do not melt upon heating– Forms links or chemical bonds between adjacent chains, during curing (intra-molecular bonds) – Three dimensional rigid network – Properties depend on the molecular units, and the length and the density of the cross-links– Thermosetting resins are usually isotropic – Mostly epoxies, silicones, urethanes

Electronic Pack….. Summary Slide 89

Adhesives

• Adhesive as underfill– Bump lifetime under

thermal cycling decreases with induced strain

– Bumps without underfill:

– CTE mismatch => cyclic shear strain

– Crack growth

– Bumps with underfill

– Strain reduction

– Lifetime increase 10X

Electronic Pack….. Summary Slide 90

Adhesives

• Anisotropic Conductive Adhesive– The adhesive film is applied uniformly

– Pressure is applied during curing, giving conduction only between pads

– Thermoplastic or thermosetting

– Film (tape) or paste

– Monodispersive spheres can be used

Electronic Pack….. Summary Slide 91

Green electronics

• Life Cycle Perspective– The environmental

impacts in the different stages in a products lifecycle are generated e.g. from :

• Inputs like energy and raw materials

• Outputs like emissions to earth, air and water

• Production of solid waste

• Problems with the occupationalhealth and safety

Electronic Pack….. Summary Slide 92

RoHS – in brief

• The RoHS Regulations ban the placing on the EU market of new Electrical and Electronic Equipment (EEE) containing more than the set levels of lead, cadmium, mercury, hexavalent chromium and both polybrominated biphenyl (PBB) and polybrominated diphenyl ether (PBDE) flame retardants from 1 July 2006. There are a number of exempted applications for these substances.

• Manufacturers will need to ensure that their products - and the components of such products - comply with the requirements of the Regulations by the relevant date in order to be placed on the Single Market. The Regulations will also have an impact on those who import EEE into the European Union on a professional basis, those who export to other Member States and those who rebrand other manufacturers’ EEE as their own.

• These Regulations do not affect the application of existing legal requirements for EEE, including those regarding safety, the protection of health, existing transport requirements or provisions on hazardous waste. In other words, existing

legislation on EEE and hazardous substances must also be complied with.

Electronic Pack….. Summary Slide 93

Legislation• EEE has the authorities' attention, primarily because of the rising amounts of

waste and the connected disposal problems.

• This is the reason why since the beginning of the nineties there has been an ongoing work on legislation in this field, starting in Germany, Denmark, The Netherlands, Sweden and Norway, as well as on the EU-scale.

• The regulations are primarily concerned with:– establishing collection systems and securing correct handling of waste, which

means recycling and regaining of resources

– safe separation and disposal of environmental hazardous parts

– certain hazardous substances, which will either be banned or restricted in use

• The regulations also introduces a producer responsibility for the disposal, and demands information from the producer to the recycler about e.g. the content of environmentally hazardous parts and possibilities for recycling.

Electronic Pack….. Summary Slide 94

Leadless soldering• Leadless soldering replacing lead-based solder due health hazards and

environmental issues

Electronic Pack….. Summary Slide 95

The MultiMEMS MPW Process

• Schematic view of the MultiMEMS MPW process from Infineon Technologies SensoNor

Electronic Pack….. Summary Slide 96

The Tronic’s MPW Process

• Schematic view of the Tronic’s MPW process SOI HARM (Silicon On Insulator High Aspect Ratio Micromachining)

HF release

Si = 300µm

Hermetic Sealing

Si = 60µm

Gold contacts

DRIE > 1:20Min. gap: 3µmMin. Feat.: 4µm

BOX=2µm

Opening for light, fluids, gas or vacuum

Low vacuum sealed cavity

Si = 450µm

Copyright 2006 John Wiley & Sons, Inc. 4-97

Process Capability

(b) Design specifications (b) Design specifications and natural variation the and natural variation the same; process is capable same; process is capable of meeting specifications of meeting specifications most of the time.most of the time.

Design Design SpecificationsSpecifications

ProcessProcess

(a) Natural variation (a) Natural variation exceeds design exceeds design specifications; process specifications; process is not capable of is not capable of meeting specifications meeting specifications all the time.all the time.

Design Design SpecificationsSpecifications

ProcessProcess

Copyright 2006 John Wiley & Sons, Inc. 4-98

Process Capability

(c) Design specifications (c) Design specifications greater than natural greater than natural variation; process is variation; process is capable of always capable of always conforming to conforming to specifications.specifications.

Design Design SpecificationsSpecifications

ProcessProcess

(d) Specifications greater (d) Specifications greater than natural variation, but than natural variation, but process off center; process off center; capable but some output capable but some output will not meet upper will not meet upper specification.specification.

Design Design SpecificationsSpecifications

ProcessProcess

Copyright 2006 John Wiley & Sons, Inc. 4-99

Process Capability Measures

Process Capability Ratio

Cp =

=

tolerance range

process range

upper specification limit - lower specification limit

6

Copyright 2006 John Wiley & Sons, Inc. 4-100

Computing Cp

Net weight specification = 9.0 oz 0.5 ozProcess mean = 8.80 ozProcess standard deviation = 0.12 oz

Cp =

= = 1.39

upper specification limit - lower specification limit

6

9.5 - 8.5

6(0.12)

Copyright 2006 John Wiley & Sons, Inc. 4-101

Process Capability Measures

Process Capability IndexProcess Capability Index

CCpkpk = minimum = minimum

xx - lower specification limit - lower specification limit

33

==

upper specification limit -upper specification limit - x x

33

==

,,

Copyright 2006 John Wiley & Sons, Inc. 4-102

Electronic Pack….. Summary Slide 103

Copyright 2006 John Wiley & Sons, Inc. 4-104

Electronic Pack….. Summary Slide 105

End of Summary• Use this summary lecture as a guideline to what is considered the most

important parts of the course syllabus.

• Look at earlier exam tests and guides to get a feeling of the kind of questions that will be asked.

• Get the basic overview, and know the differences between the different technologies («Getting a C grade»)

– For instance, do not wrongly describe the process technology asked for by intermixing it with another technology – for instance know the differences between thick film technology and thin film technology.

• Then, start to learn and understand the finer details to be able to show you have a deep knowledge of the syllabus («Going for the A grade»)

• An understanding of work done in the Compulsory Project is expected, and highly probable a part of the Final Exam! (Active group membership will be hounoured – passivity punished)

• Good luck with your Examination Test, and thank you for attending this course!

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