wafer level packaging & bumping – a view from a european ... · pdf filecertified...

Certified ISO 9001:2000 & ISO TS 16949

9th International IEEE CPMT Symposium on High Density Design,Packaging and Microsystem Integration (HDP’07)

26th-28th June 2007Shanghai, China

Wafer Level Packaging & Bumping– A view from a European Service Provider

Thomas OppertVP Marketing & Sales

oppert@pactech.de

Certified ISO 9001:2000 & ISO TS 16949

• Overview on Semiconductor Markets– 1970 to 2010– Applications and usage/implementation of eless NiAu

• ENIG UBM – History & Now– The early days of eless NiAu– Licenses & worldwide wafer bumping capacity– Pac Tech and eless NiAu now– Equipment for eless NiAu

• Soldering– Paste Printing– Single Ball Placement– Gang (Micro) Ball Placement

• Summary

Content

Certified ISO 9001:2000 & ISO TS 16949

Overview on Overview on Semiconductor MarketsSemiconductor Markets

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Evolution Semiconductor Market 1970 - 2010

Military/ Aerospace

Government

Enterprise

Internet

Consumer/Wireless

Source: SIA

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Semiconductor Market 2006

PC/ Computer 43,70%

Cell Phone/ mobil 17,00%

Wired Comm 7,00%

Industrial/ Military 7,30%

Automotive 8,70%Consummer

17,20%

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Products using electroless Ni/Au

• …First for products under very high price pressure (RFID)

• Meanwhile wide range of applications- ASIC (Sensors)- LCD Drivers- PowerMOS (Automotive)- Protection devices (Passives) CSP‘s, WLCSP‘s- Memories and memory modules- Consumer electronics- Mobile Phone- Medical (Ear phone)

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Worldwide use of Pac Tech eless Ni & solder printing

Mobile Phone; 40,00%

MOSFET; 20,00%

RFID; 20,00%

Memory; 5,00%

LCD Driver/ ASIC; 5,00%

Medical; 10,00%

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Electroless Electroless NiAuNiAuHistory & NowHistory & Now

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A Crazy Idea?• Technically impossible• Wrong concept• Not reliable• No infrastructure• Economically not feasible• hard to control dangerous / critical• Will be never accepted by customer

Electroless Ni/Au for Semiconductor Devices

Sounds familiar?

19901990

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A Crazy Idea?• Technically impossible• Wrong concept• Not reliable• No infrastructure• Economically not feasible• hard to control dangerous / critical• Will be never accepted by customer

Remember:

18861886

Certified ISO 9001:2000 & ISO TS 16949

History of electroless Ni/Au @ Pac Tech

• Basic studies & publications in 1985• First active electroless bumped wafer in 1989• Formation of Pac Tech in 1995• Further developments of the eless Ni UBM• Pilot production line in 1997• Start of customer qualification & production in 1998

2007…Pac Tech Wafer Bumping facilities in Germany, USA, Japan, Malaysia

…10x Pac Tech eless NiAu Bumping processlicensed and equipment installed worldwide

Certified ISO 9001:2000 & ISO TS 16949

1st Ni Bumps1st Ni Bumps 19901990

Certified ISO 9001:2000 & ISO TS 16949

Certified ISO 9001:2000 & ISO TS 16949

…more electroless Ni/Au

• ENIG NOT only for Al, also for Cu pads• ENIG UBM for FC and Wire Bonding• Eless Ni/Pd/Au for Wire Bond of Power

Devices

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2000 2001 2002 2003 2005 2006 2007 2008 Year

Gro

wth Japan

(ABT)

Subcon

Korea(STW)

LCD-Driver

USA

Memory

USA

(PacTech)

SubCon

USAPower Dev.

Business Development – Installed Equipment for ENIG UBM & Technology Transfer/Licenses of Pac Tech

Philippines

Telecom.

France

Telecom.

Germany

Telecom.

FranceQ2/07

Taiwan

Q4/07

Malaysia

Q3/07

Japan

Nagase

300 mm

300 mm

300 mm

300 mm

300 mm300 mm

300 mm

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150k600kPac Tech Asia

150k600kABT ("Pac Tech Japan")

150k600kPac Tech USA

100k600kPac Tech GmbH

<12" Wafer><4-8" Wafer>2008

100k300kPac Tech Asia

-600kABT ("Pac Tech Japan")

150k600kPac Tech USA

100k600kPac Tech GmbH

<12" Wafer><4-8" Wafer>2007

-450kABT ("Pac Tech Japan")

150k600kPac Tech USA

100k600kPac Tech GmbH

<12" Wafer><4-8" Wafer>2006

Pac Tech Group Worldwide Wafer Bumping CapacityPac Tech Group Worldwide Wafer Bumping Capacity

Certified ISO 9001:2000 & ISO TS 16949

Wafer Level UBMWafer Level UBMElectroless Electroless NiAuNiAu

Certified ISO 9001:2000 & ISO TS 16949

Process Flow - Electroless Ni/Au Bumping

Al Pad Cu Pad

Zinkating Pd Seed

Ni Plating

Flash Au Flash Au

Thick AuFlash Au

Pd Barrier

FCB Wire Bonding Wire Bonding

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Backside Coating

Pad Cleaning

Pad Activation

Electroless Nickel

Flash Gold

Coating Removal

Under Bump Metal Process

Electroless Plating of Ni/Au Bumps on Al pad 1/2

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Backside Coating

Aluminum Cleaning

Zincate Pretreatment

Electroless Nickel

Immersion Gold

Coating Removal

Under Bump Metal Process

Electroless Plating of Ni/Au Bumps on Al pad 2/2

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Electroless Electroless Ni/Au on Copper Pad

Backside Coating

Pad Cleaning

Pd Treatment

Electroless Nickel

Flash Gold

Coating Removal

300 mm Capability !

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Backside Coating

Aluminum Cleaning

Zincate Pretreatment

Electroless Nickel

Electroless Palladium

Immersion Gold

Coating Removal

Electroless Ni/Pd/Au Bumping on Al Electroless Ni/Pd/Au Bumping on Al

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Flip Chip Modules for contactless Smart Cards

Interconnection: Electroless NiAu with ACF

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Pacline 300 - A50

10 Plating Systems in the Field

300 mm

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- Capability for parallel processing of 3 carriers with 50 wafers 8“ or 3 carrierswith 26 wafers 12”- UPH: max. 150 Wafers 8"/hour or max. 78 wafers 12”/hour (5µm Ni/Au UBM)- Thick Au ability for wire bonding reliability- Ni bath control with ConPac 2.0 (bath conditioner) and ConPac control set- Central Computer Control Unit (CCCU)- PLC with Profi Bus system- Additional security tanks for each module and pump system- Design will be adapted to customer’s facility- SECS GEM Interfacing- The system fulfils the fire safety standard FM 4910

Pacline 300 - A50

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Wafer Level Solder PrintingWafer Level Solder Printing

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Comparison of Solder Bumping Technologies

Evaporated SolderBump

Sputtered UBM + Plating

Sputtered UBM + Print (FCT)

Electroless UBM (+) Print or Ball Attach

C4 Solder Solder

Au

Solder Solder

Ni/Au

Electroless UBM (+) Print or Ball Attach

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PbSn

Electroless Ni/Au Bumping

Solder Paste Printing

Reflow

Wafer Cleaning

Wafer Inspection

Pack & Ship

Stencil Solder Printing Process FlowStencil Solder Printing Process FlowSnPb37, LeadSnPb37, Lead--free: free: SnAgCuSnAgCu

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Applications for mobile phone

GSM Phone: Battery ControlWafer: Si-Ge Technology

Protection Devices

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Solder Printing on 300mm Wafer

• 740.000 I/O per Wafer• 680 I/O per Chip• 225µm pitch• 100µm pad size• 70µm solder ball height

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Solder Ball PlacementSolder Ball Placement&&

Laser ReflowLaser Reflow

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Laser Soldering SB2-Jet

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SB2 – Equipment

SB²-Jet LF

Semiautomatic SB²-SM

Automatic SB²-Jet

300 mmESD version of SB²-JetFor HGA & HSA Assembly

SB²-Jet LF with R2R Machines sold > 200 pcs

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SB2-Jet Advantages

• No tooling• Solder ball diameters from 80(60)µm - 760µm• Solder alloys: SnPb, SnAg, SnAgCu, AuSn• No flux• No mechanical stress/contact• No thermal stress• No additional reflow• No cleaning of flux residues• Fine pitch applications (110µm/100µm)

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SB2-Applications

• Wafer Bumping• BGA/ CSP Bumping• Wafer Level CSP Bumping• Rework/ Repair• Optoelectronic Packaging• SAW, BAW• MEMS & 3-D Packaging• Hard Disk Drive (HGA, HSA)• Camera Modules

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A

B

C

3D – AssemblyDesign Considerations

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Source: Seagate

Fluxless 3D-Ball Placement & Laser Reflow on FlexSuspension for HDD (HGA)

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Silicon stator(non-moving, attached to suspension)

Silicon rotor(moving, holds magnet and slider

Magnet/ buttom keeper

Narrow beam flexure(connects rotor to stator)

Read / write transducer

Electrical connections to read / write sliderElectrical connections to drive coil

Suspension

369

Fluxless 3D-Ball Placement & Laser Reflow on FlexSuspension for HDD (HGA)

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Gang (Micro) Ball Placement

Certified ISO 9001:2000 & ISO TS 16949

Automatic Gang Ball Placer for Micro Ball Placement 1/2

• Cassette to Cassette robot handling f. wafer up to 12“

• Integrated rework capability• 100% yield

• 2x optical inspection• 1st after ball transfer• 2nd after repair

• min ball size 100µm• pre- fluxing by printing/spraying• UPH 5min/Wafer (8“)

1st fully auto machine already installed in Japan

300 mm Capability !

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Gang Ball Placer for Micro Ball Placement 2/2

• 8“ Wafer• Pitch 200µm• 400.000 I/O‘S• 100µm solder balls SnAgCu

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Wafer Level CSP Application

• eutectic SnPb or lead-free• pitches: 180µm – 1mm

• wafer sizes: 4” – 8”• solder ball diameter: 100 - 760 µm

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Solder Ball Transfer by GBP - Ball Pickup

MaskSolder Ball Bond Tool

Vibration

Vacuum

1

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Solder Ball Transfer by GBP – Ball Placement

2

3

Mask

Wafer

Solder Ball

UBM

Flux

Bond Tool

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Placement Force

Gravity only

Ball Drop vs. Ball Transfer

Ball Drop Process

• Weak solder bump adhesion to UBMdue to insufficient flux wetting of solder ball

• “Ball Escape” out of dispense unit possible

Ball Transfer Process

• much better fluxing process due to application of additional placement force

• “Ball Escape” not possible

Certified ISO 9001:2000 & ISO TS 16949

• Overview on Semiconductor Markets

• Electroless NiAu UBM – History & Now– Eless NiAu for Al and Cu– Eless NiPdAu

• Soldering Processes– Paste Printing– Single Ball Placement– Gang (Micro) Ball Placement

Summary

Certified ISO 9001:2000 & ISO TS 16949

Questions ?