Managing Lead and LeadFree Transition

1
Managing Lead and Lead-Free Transition

• Dr. Sudarshan Lal
• FCI USA, Inc.
• Etters, PA (USA)
• June 20, 2002

2
Outline

• Introduction
• Lead-free test plans
• Lead-free implementation for
• i) Pressfit ii) Reflow iii) BGA Applications
• Test status
• Conclusions

3
Market Segment Requirements

• Commercial 2003
• Industrial Not Clearly Defined
• Computer 2003
• Telecom/Backpanel Not Clearly Defined

• Board and connector performance issues are the
  cause for a less defined need in the
  Telecom/Backpanel market

Request for segment data made to fleck and bishop
4
Regions Timing Requirements

• Americas Not Clearly Defined
• A/P 2003 (Some Appliances in Japan)
• Europe 2006 (Servers Auto. 2010)
• Although there is no legislation, pending or
  otherwise, Japan is calling for the reduction or
  elimination of lead in Electronics. Several
  Japanese OEMs have taken it upon themselves to
  be as proactive in this market as possible

5
Timing Requirements Europe A/P

• The use of lead in electronics assembly within
  the European Union will be banned after January
  2008 (and possibly as soon as 2006). Servers and
  Automotive exempted until 2010
• Since A/P, specifically Japan, is the first
  regional area to require lead-free products,
  FCIs lead-free implementation will be heavily
  influenced by the needs and requirements of major
  Japanese OEM customers.

SourceEnvirowise Website http//www.envirowise.go
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6
Lead-Free Global Team Charter

• Provide leadership, coordination, and
  communication to FCI Worldwide to implement a
  lead-free offering of our products where
  appropriate in a way that
• Identifies marketing and customer expectations
• Establishes product conversion priority and
  timing
• Provides leadership and communication
• Coordinates activities with the other regions
• Provides technology solutions for our products
• Assures the generation and communication of
  technical support data, and
• Generates an implementation plan that includes
  sales, marketing, engineering, manufacturing, and
  technology actions and timing
• so that FCI can provide a lead-free product
  offering that meets the needs of our customers in
  a timely manner and meets our business
  objectives.

7
Lead-Free Team Methodology
Rather than focus on 40 product lines, the
lead-free team will focus on the three main
termination styles. Each termination style
will have a different technical solution or a
significantly different performance or whisker
issue that needs solving.
8
Implementation By Termination Style
Thru-Hole
SMT
BGA Termination
Reflow
Press-Fit
9
Advantages of Sn-Cu v. Sn coating

• Aesthetically superior bright deposit with low
  carbon stable alloy composition
• Sn-Cu is less prone to whiskering than pure tin .
  Alloying helps in whisker mitigation
• Low foam, stable solution without strong odors
  for Sn-Cu bath
• Plated Sn-Cu film resistant to discoloration in
  heat tests
• Solderability for Sn-Cu coating is equivalent or
  better than Sn-Pb and pure tin finishes. Tin
  coatings after steam aging exhibited poor
  solderability (longer wetting times, negative
  forces)

10
Technical Solution
Press-Fit Reflow Sn-Cu Plating ( Bath
Globally Available) BGA Sn-Cu-Ag Spheres
(Spheres Globally Available) Note FCI Searching
Lead-Free Epoxy to Withstand 260 C
11
Press-Fit Lead-Free Implementation Flow Chart
Perform DOE And Test Plan Utilizing Multiple
Boards
Connector Technical Solution Sn-Cu Plating
Test Boards Immersion Ag Immersion Sn Bare
Cu/OSP Tin/Lead Nickel Gold
Confirm Technical Solution In Press-Fit
Applications
12
Lead-Free Press-Fit Test Plan

• Utilizing a Metral EON press-fit pin
• Testing conducted with Tin-Lead, OSP, ImAg,
  ImSn, Ni-Au Boards
• Telecom UE Tests
• Vibration Shock 50 Contacts Min. Max. PTH
  Board
• Thermal Shock/Humidity 50 contacts Min.
  Max. PTH Board
• Mixed Flow Gas 25 Contacts Max. PTH Board
  Only
• Repair (Insertion/Retention, Heat Age, Hole
  Deformation) 150 Contacts Min. Max. PTH Board

13
Press-Fit Test Results Status

• Vibration Shock No abnormalities found
• Thermal Shock/Humidity test In Progress
• Mixed Flow Gas Initial Preparation Completed.
  Going to MFG chamber
• Repair (Insertion/Retention, Heat Age,
  Hole-size) Passed within normal limits
• Compliant pin resistances were within
  specifications (less than 1 milliohm)

14
BGA Implementation Flow Chart
Perform DOE And Test Plan Utilizing Copper Board
Connector Technical Solution SnCuAg BGA
Test Boards Bare Cu/OSP
Confirm Technical Solution In BGA Applications
15
Lead-Free BGA Test Plan

• Test PCB Pad Plating OSP (Cu with Coating)
• 1.) Thermal Shock Testing Per MEG-Array Product
  Spec GS-12-100
• 2.) Solder Joint Tensile Strength 3-Point Bend
  Testing per MEG-Array Product Specification
  GS-12-100 2a. Solder ball pull strength.
• 3.) Solder Wicking Evaluation
• 4.) Thermal Cycling per IPC-SM-785 (Telecom
  Central Office Environment)

16
Lead-Free BGA Test Results

• Passed three-point bend test. No dye penetration
  observed. Micro-cracks were absent
• Lead-free solder tensile strength was greater
  than standard Tin-lead solder
• Solder joint reliability was equivalent to
  Tin-lead

17
Re-flow Termination Implementation Flow Chart
Perform DOE And Test Plan Utilizing Copper Board
Connector Technical Solution Sn-Cu Plating
Test Boards Bare Cu/OSP
Confirm Technical Solution In Re-flow Applications
18
Lead-free Re-flow Test Status

• Solderability was excellent exhibiting normal
  forces and percentage coverage comparable to
  Tin-lead
• Tensile Strength using Instron was similar to
  Tin-lead
• Whisker tendency not studied yet. Reflow should
  minimize whisker formation
• Need to develop plan for i) Bergstik-thruhole
  ii) Bergstak-SMT iii) Memory-SMT Products

19
Resins Molding For Lead-Free
Three resins failed to withstand the industry
anticipated 260C peak re-flow temperature for
lead free soldering. These resins are
LCP A (280C) (Baby HMetral
Headers) PPS (Card Edge Press-Fit) SPS (GBIC
SMT) Polyamide 46 Polyphthalamide high
temperature nylons passed at all re-flow
temperatures in the dry state, but failed at all
re-flow temperatures (even the current 223C) in
the wet state via blistering. The failures were
due to the hygroscopic property of the material
and not the re-flow temperature.   In general,
those materials with a melting point of 285C and
lower exhibited visual and/or dimensional defects
following exposure to 260C and higher re-flow
temperatures. All resins with melting points
greater than 285C successfully sustained the
industry anticipated 260C peak re-flow profile
without visual/dimensional damage.
Converged EON Metral Headers Use LCP E Melt
Temp 335C
20
Existing FCI Lead-Free Products
21
Conclusions

• FCI maintains an open dialogue with suppliers,
  contract manufacturers, OEMs and consortia
  regarding lead-free technical solutions.
  Presently customers are interested in plans ,
  capabilities and limited test samples
• The global lead-free team is in the process of
  identifying testing lead-free solutions for
  BGA, press-fit re-flow products
• Implementation and smooth transition shall be
  case-by- case based on credible scientific data
  of proven reliability, market demand, regulatory
  compliance, supply assurance, quality and
  competitive cost