Digital Integrated Circuits A Design Perspective

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© Digital Integrated Circuits2nd Manufacturing

Digital Integrated Digital Integrated CircuitsCircuitsA Design PerspectiveA Design Perspective

ManufacturingManufacturingProcessProcess

Jan M. RabaeyAnantha ChandrakasanBorivoje Nikolic

July 30, 2002

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CMOS ProcessCMOS Process

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A Modern CMOS ProcessA Modern CMOS Process

p-well n-well

p+

p-epi

SiO2

AlCu

poly

n+

SiO2

p+

gate-oxide

Tungsten

TiSi2

Dual-Well Trench-Isolated CMOS ProcessDual-Well Trench-Isolated CMOS Process

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Circuit Under DesignCircuit Under Design

VDD VDD

VinVout

M1

M2

M3

M4

Vout2

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Its Layout ViewIts Layout View

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The Manufacturing ProcessThe Manufacturing Process

For a great tour through the IC manufacturing process and its different steps, checkhttp://www.fullman.com/semiconductors/semiconductors.html

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oxidation

opticalmask

processstep

photoresist coatingphotoresistremoval (ashing)

spin, rinse, dryacid etch

photoresist

stepper exposure

development

Typical operations in a single photolithographic cycle (from [Fullman]).

Photo-Lithographic ProcessPhoto-Lithographic Process

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Patterning of SiO2Patterning of SiO2

Si-substrate

Si-substrate Si-substrate

(a) Silicon base material

(b) After oxidation and depositionof negative photoresist

(c) Stepper exposure

PhotoresistSiO2

UV-light

Patternedoptical mask

Exposed resist

SiO2

Si-substrate

Si-substrate

Si-substrate

SiO2

SiO2

(d) After development and etching of resist,chemical or plasma etch of SiO2

(e) After etching

(f) Final result after removal of resist

Hardened resist

Hardened resist

Chemical or plasmaetch

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CMOS Process at a GlanceCMOS Process at a GlanceDefine active areasEtch and fill trenches

Implant well regions

Deposit and patternpolysilicon layer

Implant source and drainregions and substrate contacts

Create contact and via windowsDeposit and pattern metal layers

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CMOS Process Walk-ThroughCMOS Process Walk-Through

p+

p-epi (a) Base material: p+ substrate with p-epi layer

p+

(c) After plasma etch of insulatingtrenches using the inverse of the active area mask

p+

p-epiSiO2

3SiN

4

(b) After deposition of gate-oxide andsacrificial nitride (acts as abuffer layer)

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CMOS Process Walk-ThroughCMOS Process Walk-ThroughSiO2

(d) After trench filling, CMP planarization, and removal of sacrificial nitride

(e) After n-well and VTp adjust implants

n

(f) After p-well andVTn adjust implants

p

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(g) After polysilicon depositionand etch

poly(silicon)

(h) After n+ source/drain andp+ source/drain implants. These

p+n+

steps also dope the polysilicon.

(i) After deposition of SiO2insulator and contact hole etch.

SiO2

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(j) After deposition and patterning of first Al layer.

Al

(k) After deposition of SiO2insulator, etching of via’s,

deposition and patterning ofsecond layer of Al.

AlSiO2

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Advanced MetallizationAdvanced Metallization

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Advanced MetallizationAdvanced Metallization

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Design RulesDesign Rules

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3D Perspective3D Perspective

Polysilicon Aluminum

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Design RulesDesign Rules

Interface between designer and process engineer

Guidelines for constructing process masks Unit dimension: Minimum line width

scalable design rules: lambda parameter absolute dimensions (micron rules)

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CMOS Process LayersCMOS Process Layers

Layer

Polysilicon

Metal1

Metal2

Contact To Poly

Contact To Diffusion

Via

Well (p,n)

Active Area (n+,p+)

Color Representation

Yellow

Green

Red

Blue

Magenta

Black

Black

Black

Select (p+,n+) Green

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Layers in 0.25 Layers in 0.25 m CMOS processm CMOS process

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Intra-Layer Design RulesIntra-Layer Design Rules

Metal24

3

10

90

Well

Active3

3

Polysilicon

2

2

Different PotentialSame Potential

Metal13

3

2

Contactor Via

Select

2

or6

2Hole

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Transistor LayoutTransistor Layout

1

2

5

3

Tra

nsis

tor

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Vias and ContactsVias and Contacts

1

2

1

Via

Metal toPoly ContactMetal to

Active Contact

1

2

5

4

3 2

2

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Select LayerSelect Layer

1

3 3

2

2

2

WellSubstrate

Select3

5

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CMOS Inverter LayoutCMOS Inverter Layout

A A’

np-substrate Field

Oxidep+n+

In

Out

GND VDD

(a) Layout

(b) Cross-Section along A-A’

A A’

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Layout EditorLayout Editor

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Design Rule CheckerDesign Rule Checker

poly_not_fet to all_diff minimum spacing = 0.14 um.

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Sticks DiagramSticks Diagram

1

3

In Out

VDD

GND

Stick diagram of inverter

• Dimensionless layout entities• Only topology is important• Final layout generated by “compaction” program

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PackagingPackaging

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Packaging RequirementsPackaging Requirements

Electrical: Low parasitics Mechanical: Reliable and robust Thermal: Efficient heat removal Economical: Cheap

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Bonding TechniquesBonding Techniques

Lead Frame

Substrate

Die

Pad

Wire Bonding

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Tape-Automated Bonding (TAB)Tape-Automated Bonding (TAB)

(a) Polymer Tape with imprinted

(b) Die attachment using solder bumps.

wiring pattern.

Substrate

Die

Solder BumpFilm + Pattern

Sprockethole

Polymer film

Leadframe

Testpads

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Flip-Chip BondingFlip-Chip Bonding

Solder bumps

Substrate

Die

Interconnect

layers

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Package-to-Board InterconnectPackage-to-Board Interconnect

(a) Through-Hole Mounting (b) Surface Mount

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Package TypesPackage Types

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Package ParametersPackage Parameters

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Multi-Chip ModulesMulti-Chip Modules

Documents

Digital Integrated Circuits A Design Perspective