Burn-in & Test Socket Workshop

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March 3-6 , 2002

Hilton Phoenix East/Mesa Hotel Mesa, Arizona

Burn-in & Test

Socket Workshop

IEEE

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COPYRIGHT NOTICE

• The papers in this publication comprise the proceedings of the 2002

BiTS Workshop. They reflect the authors’ opinions and are reproduced as presented , without change. Their inclusion in this publication does not constitute an endorsement by the BiTS Workshop, the sponsors, or the Institute of Electrical and Electronic Engineers, Inc.

· There is NO copyright protection claimed by this publication. However, each presentation is the work of the authors and their respective

companies: as such, proper acknowledgement should be made to the appropriate source. Any questions regarding the use of any materials presented should be directed to the author/s or their companies.

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Burn-in & Test Socket Workshop

Session 8

Wednesday 3/06/02 10:30AM

New Products

“Kelvin Contacting Solutions For Leadless Device Types”

Gerhard Gschwendtberger - Multitest Elektronische Systeme GmbH

“Interconnecting At 40 GHz and Beyond”

Roger Weiss, PhD - Paricon Technologies Corporation

“Electro-chemical Cleaning Process”

Erik Orwoll - Nu Signal LLC

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Kelvin Contacting Solutions for

Leadless Device Types

Gerhard Gschwendtberger Product Manager Contactors

(5)

(6)

Leadless Packages

Leadless Packages = JEDEC compliant QFN plastic package MO-220/MO-229

VQFN MLP

MLF

VQPFN

etc.

Typical Package Sizes:

2x1mm 3/5 lead up to 9x9mm 64 lead Body thickness ~1mm

(7)

Kelvin Contactors

7 6 2 1 R R R R = R R × if

Kelvin contactors are typically used for sensitive resistance measurements at Analog/Mixed Signal- and Automotive applications

Electrical principle: Two independent electrical

connections to the device lead allow to compensate parastic resistances between DUT and Tester.

(8)

New technology required

IC Package Trends

D o w n S i z i n g

device size, lead pitch/size

DIP, TO SOJ

SOP, SSOP

TSSOP Leadless

Current Kelvin contactor technologies

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Kelvin Contactors for Leadless Devices

Typical Kelvin Contactor Solution for SOP, SSOP, TSSOP Packages

◆_{contact springs}

on the top and bottom of the device lead

◆_{contact spring wider}

than device lead

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Kelvin Contactors for Leadless Devices

Design Objectives

Mechanical

◆ _{Leadless packages down to 0.4mm lead pitch}

◆_{Modular design to enable multi-site testing}

◆_{Integrated solution at Pick & Place}

and Gravity test handlers

◆ _{High durability & lifespan}

◆_{Field serviceable}

(11)

Electrical:

◆ _{High current capability}

◆_{Repeatable contact resistance values}

◆_{Low inductance}

Thermal:

◆ _{Temperature range -55°C through 155°C}

Kelvin Contactors for Leadless Devices

Design Objectives

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Contactor Design - Package Dimensions

Tolerances on D & E dimensions typically +/- 0.15mm 0,5 0,3 0,27 0,16 0,4 0,5 0,3 0,3 0,18 0,5 0,5 0,3 0,35 0,23 0,65 0,75 0,5 0,4 0,28 0,8 0,75 0,5 0,47 0,35 1,27 L (max) L (min) B (max) b (min) Lead Pitch e

(13)

Contactor Design - Technology

Pad dimensions lead pitch 0.4mm Contact area worst case:

0.16 x 0.3 = 0.048mm2

Kelvin contact spring

(14)

Contactor Design - Features

Kelvin contact spring block

◆ Molded tungsten needles

◆ No scrub

◆ Needles penetrate oxide

◆ 0.3N @ 0.3mm deflection ◆ 0.1mm distance between adjacend needles ◆ Minimum spring pitch 0.4mm ◆ PC board 10mm distance to DUT

(15)

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Contactor Design - Features

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Contactor Design - Socket Arrangement

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Contactor Design - Dual Contact Unit

Guide pins

(handler docking)

Air connection Temperature

insulation Base Plate Guiding holes (plunger reference) Kelvin contact spring block

(19)

d

Contactor Design - Device Positioning

Gravity test handler - vacuum plunger

Guiding door

Guiding bar

Device

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Design Evaluation - Contact Springs

Contact spring marks

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Design Evaluation - Contact Springs

Contact spring marks MLF 4x4 20lead 0.5mm

Contact springs

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Design Evaluation - Resistance Distribution

Contact resistance measurements taken from 100 Devices MLP6x5 8lead Temperature ambient 0 50 100 150 200 250 300

Contact Resistance mOhm

Num

ber o

f sources

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Design Evaluation - Contact Resistance

80 90 100 110 120 130 140 150 1 51 101 151 201 251 301 351 401 451 PIN 1 PIN 2 PIN 3 PIN 4 PIN 5 PIN 6 PIN 7 PIN 8

Contact resistance versus number of insertions (ambient)

Res

istance

mO

hm

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Evaluation Results - Maximum Current

0 1 2 3 4 5 6 7 8 9 10 10 50 100 250 500 1000 Pulse (ms) Cur re n t I ( A )

Max. Current Amp

Maximum test current versus pulse duration

Base:

(25)

Evaluation Results - Temperature Accuracy

1 5 0 1 5 2 1 5 4

4 0 8 0 1 2 0 1 6 0

Temperature drift DUT during test at 155°C

Start of test

Time s

Temper

ature

°C

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Evaluation Results - Temperature Accuracy

-6 0 -5 8 -5 6 -5 4 -5 2 -5 0 0 4 8 1 2 1 6 2 0 2 4 2 8 3 2 3 6 4 0 4 4 4 8 5 2 5 6 6 0 6 4 6 8 7 2 7 6 8 0 Time s

Temperature drift DUT during test at - 55°C

Temper

ature

°C

Start of test

(27)

Thermal:

Temperature range -55°C up to 155°C

Electrical:

Contact resistance typ. 130mOhm

Maximim current continuous 1 Amp

Mechanical:

Package JEDEC MO220 / MO229

Lifespan min 1Mio insertions

Contact force 0.3N

Contact deflection 0.3mm

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®

Interconnecting at 40 GHz

and Beyond

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®

Problem Definition

Electronic Capability Continuously Evolves

Smaller, Faster, Better Performance,

Lower Cost and More Functionality

L Computer Speed and Size

L Wireless and Telecom

L Military

L Medical

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®

Core Technology

Paricon’s Interconnect Technology

Based on Controlled

Electromagnetic Alignment of

Ferro-Magnetic Particles Within a

Polymer Matrix

(31)

®

Core Technology

After Several Years of Research Paricon Has

Perfected a Long Promised Capability

LCore Technology Acquired From Bell Labs

LHigh Performance Materials Developed

LImproved Manufacturing Methods

Introduced

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®

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Our Name

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Contact Resistance

TH RO UG H RESISTANCE CURVE 0 5 10 15 20 25 -3 -2 -1 0 1 2 3 Norm al Probability Contact Resistance (M illi Ohm s) Set 1

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Rise Time

TDT thru -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2 250 300 350 400 t [ps] Rh o THRU probes THRU Mat'l. A THRU Mat'l. B THRU Mat'l. C

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®

Electrical Parameters

Shunt Capacitance (G-S-G) 30 femto Farad

Self Inductance 70 pico Henry

Rise Time (Same as Test System) 32 ps

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®

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11

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Resistance vs. Temperature

Thermal Coefficient Of Resistance

0 2 4 6 8 10 12 0 20 40 60 80 100 Resistance (mohm) Average Resistance Silver Best Fit R=R₀[1+αααα₁(T-T₀)+αααα₂(T-T₀)2] αααα1=6.76x10 -3 C-1 αααα2=72.9x10 -6 C-1

(39)

®

Material Properties

L Isolation Gap

*

: As low as 0.010”

L Nominal Operating PSI: 15 - 100 PSI

L Current Capability

*

: Up to 1 Amp for 25 mil pad

L Environmental Seal: Silicone Gasket

L Size/Shape: Any shape < 12” x 30”

L Pad size

*

: .025 inches Typical

L Contact Materials: Noble Metals

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®

Material Properties

L Solvent Resistance: Excellent

L Thermal Conductivity: 2 W/m -°°°°C

L Pitch: Engineered

L Thickness: 8-15 mils

L Op. Temperature Range: - 40 to 160 C

L Storage Temperature: -170 to 160 C

L Durability: >500,000 cycles at 18 PSI

(41)

®

Material Properties

L Burn-in Cycles >500 to 150 C

L Contact Resistance <20 milliohms

L Inductance: 70 pH

L Capacitance: .03 Pico farads

L Insulation Resistance: > 1 gig ohm

L Frequency Range: At least 40 GHz

L Glitch >2500 Hours per EIA-540

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®

L

Performance

L

Scalability

L

Cost

L

Quick Time to Market

L

Highly Configurable

L

Enables New Approaches

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®

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®

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®

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®

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®

ü Benefits of the PariPoser® Anisotropic

Conductive Interconnection Fabric.

vConducts Only in the Z-Axis

vProvides Multiple Signal Paths per Pad.

vExceeds Industry Electronic Needs.

vExtendable to Very High Density.

vInterconnect at 40 GHz and Beyond

vExtends Interconnection capabilities to new

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®

Projected Capability

vDie scale interconnection

§ 0.004” pitch demonstrated

vWafer Scale Test Probe for 300mm

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ELECTRO-CHEMICAL

CLEANING PROCESS

March 2002 BiTS Workshop

Presented by Erik Orwoll

President Nu Signal LLC

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INTERCONNECT DEGRADATION

Causes:

èTin Lead Transfer (Metallic Formation)

èMechanical Wear (Surface finish change)

èLocalized areas of plating are removed

èPoor Plating adhesion

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TOPICS TO BE ADDRESSED

èRemoval of Tin Lead Transfer & Oxidized

Metallics

èMethod for Detecting Exposed Base Metal

èLead Free Solder

èProcess can be applied to both Burn-In and

(54)

CURRENT METHODS FOR

TIN/LEAD REMOVAL

èMechanical Removal - Typically brass or nylon

brushes. Consistency is difficult and damage can occur.

èChemical Cleaners - Can be harmful to contactor

plating, base metal, and socket housings. Also volatile & toxic.

èAbrasive - Ceramic or similar material. Can cause

damage to plating or base metal.

èUltra-Sonic Cleaning - Removes dirt and loose

particles, but has little or no effect on transferred metals.

(55)

TIN LEAD DEPOSITS

Excessive

Solder Build-Up Gold Plating

(56)

TIN LEAD DEPOSITS

Solder Build-Up Solder Build-Up

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ELECTRO-CHEMICAL CLEANING

PROCESS

èMetal fouling, which is deposited on the contactor, is

selectively removed by an electrochemical process which is innocuous to the connector base metal

èAn electrolyte is suspended between the base metal

and a collection plate, and a potential is applied

èTin Lead deposits are solubilized and deposited on

the collection plate

(58)

“REVERSE” PLATING PROCESS

èThis process is similar to standard

electro-plating. However, the potential is reversed,

causing the Tin/Lead deposits to be removed from the base metal and released into solution (See

Figures 1 & 2)

(59)

FIGURE 1

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ELECTROCHEMICAL TRANSFER

Test Set-up Collection Plate Shorted BGA Device

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DEPOSITS ON COLLECTION PLATE

Collection Plate

Solder Deposits

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MID-PROCESS CONTACT

CONDITION

Remaining Solder Solder Removed

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ELECTRICAL DATA

5.5 6 6.5 7 7.5 8 0 1 2 3 4 5 6 7 8 9 10 11 CYCLE COUNT BUL K RES IS T AN CE ( O h m s ) SOCKET #1 SOCKET #2 CLEANED

(65)

BASE METAL DETECTION

èA special solution is applied to the socket

after it has been cleaned to detect the

presence of copper. If plating is not present (typically Nickel/Gold), the exposed area will be highlighted with a stain

èThe purpose is to highlight the damaged

(66)

PERIODIC CLEANING

èCleaning should occur at regular intervals

to avoid interconnect failures

èThe number of cycles and conditions of

use determine the interval

èCommon Values:

Test Contactor - 20,000 cycles Burn-In Connector - 1000 cycles

(67)

LEAD FREE SOLDER

èLead Free Solder can be accommodated

with minor modifications to the electrolytic solution

èConcentrations of up to 5% Copper or

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PROS / CONS

Advantage

èSolder is removed without risk of mechanical

damage to base metal or gold plating

èConnector life is extended

Disadvantage

èProcess requires connectors to be cleaned

“off-line”