IPC7095 - PowerPoint PPT Presentation

Title: IPC7095


1
Design 4 Manufacture withIPC Standards
2

• Peter Burnley MIT
• Technology Centre Manager
• Electronics Yorkshire
• Eric Hinsley
• Senior Tutor
• Electronics Yorkshire

3

• Introduction to IPC
• Overview of IPC Design Acceptance Standards
• Implementation of a Manufacturable Design
• Quality Inspection

4

• IPC is a Technical Organization that meets
  Industry Requirements as it is driven by Industry
• There are many committees that sit regularly to
  discuss the changes that are happening in the
  industry
• The standards and certifications are updated
  regularly

5
Applicable IPC Standards 4 Design

• -7351 Land Pattern Considerations (IPC782)
• -7095 BGA Process Implementation
• -2315 HDI Microvia Design Guide
• -2220 Design for Manufacture
• -D-279 Design for SMT Reliability
• J-STD-001 Soldering Requirements
• -A-610 Assembly Acceptability
• -6010 Printed Board Series
• J-STD-004/005 Solder Flux/Paste
• IPC-1752 Material Declaration

6
International Organizations

• ISO - International Organization for
  Standardization
• Deals mostly with Mechanical Standards
• IEC - International Electrotechnical Commission
• Deals mostly with Electrical / Electronic
  Standards.
• Both ISO IEC managed from same location in
  Geneva, Switzerland
• Occasional overlap between ISO and IEC
  programming
• Both require participating Country support

7

• IPC defines 3 levels of product quality for
  Manufactures to build to and designers to aim
  for.
• Class 1 - General Electronic Products
• Class 2 - Dedicated Service Electronic Products
• Class 3 - High Reliability Electronic Products
• There are more defined classifications within the
  sub categories of IPC standards

8
Overview of IPC Design Acceptance Standards
9
Design Acceptance Covers

• The guidelines are constantly evolving on Rigid,
  Flex boards and assemblies, pc cards, modules,
  embedded passive components
• Other new technologies intended to address
  tighter tolerances, greater electrical
  capabilities and increased product performance
  requirements.
• Consideration is also given on CAD/CAM capability
  and data transfer from supply source.

10
Electronic Equipment Design

• IPC-2221
• Generic Standard on Printed Board Design
• IPC-2222
• Sectional Standard on Rigid Organic Printed
  Boards
• IPC-2223
• Sectional Design Standard for Flexible Printed
  Boards
• IPC-2224
• Sectional Standard of Design of PWB for PC Cards
• IPC-2225
• Sectional Design Standard for Organic Multichip
  Modules (MCM-L) and MCM-L Assemblies
• IPC-2226
• Sectional Design Standard Guide for High Density
  Interconnects Microvias
• IPC-2315
• Design Guide for High Density Interconnects
  Microvias
• IPC-2316
• Design Guide for Embedded Component
  Technology(will become IPC-2227)

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Whats Involved in theDocumentation Package

• Fabrication Drawings
• Assembly Drawings
• Bill of Materials
• Schematic or Logic Diagrams
• Wiring Diagrams
• Specification Control Drawings
• Electronic Data
• Mechanical Drawings

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Design Issues

• Land pattern concepts
• Component selection
• Mounting substrate design
• Assembly methods
• Method of test
• Phototool generation
• Meeting solder joint requirements
• Stencil fixture requirements
• Providing access for inspection
• Access for rework and repair

13
Manufacturing Allowance

• The courtyard represents the starting point of
  the minimum area needed for the component and the
  land pattern
• Manufacturing allowance must be considered in
  the design process
• Manufacturing, assembly and testing
  representatives should be involved in determining
  the additional room needed to accommodate
  placement, testing, modification and rework

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IPC-7351 Land Pattern Software
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Whats Next?

• New Design Standards
• Major support by CAD tool providers
• National Institute Standard Technology (NIST)
  viewer can be used to check data files
• NIST Gerber to IPC-2581 conversion
• New tools becoming available daily

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Material Selection
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Material Requirements Cover

• Existing standards
• New materials being developed to meet higher
  temperature assembly due to lead free
  implementation
• Assembly materials
• Requirement for halogen free laminate

18
Standards for Laminates

• Flexible Laminate
• Rigid and HDI Laminate
• Foil-Laminate

19
PCB Base Material

• Base materials for printed board applications are
  changing faster than at any point in their short
  45 year history.
• FR-4 is improving technically to facilitate
• Lead-free assembly
• Halogen-free assembly
• Global market place requires global
  specifications
• With new materials and technologies developed
  rapidly, governing standards must be generated
  just as fast in order to maintain a cohesive
  pattern of control

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Key Material Properties

• While there are many different material
  properties that can be measured in a laminate,
  only a few are of overriding importance in
  circuit design and are of major concern to
  designers. These properties are
• Thermal expansion
• Glass transition temperature (Tg)
• Moisture absorption
• Time to Decomposition (Td)

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Solder Alloy Selection
Solder alloys exist for the electronic industries
that have primarily been eutectic in nature.
Rework repair soldering require the same type
of solder flux combination as the original reflow
combination. With RoHS we now have a much wider
range of alloys. The predominant group are SAC (
Sn Ag Cu ) alloy, and an industry standard alloy
is the SAC 305.
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Printed Board Process Characteristics
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Surface Finish

• HASL - hot air solder leveling
• OSP - organic solderability preservative
• ENIG - electro less nickel immersion
  gold
• ImAg - immersion silver
• ImSn - immersion tin
• New Developments include DIG
• Direct Immersion Gold

24
Related Process Issues

• Solder paste application (volume
• control)
• Tented or plugged vias
• Solder flux removal vs flux residue
• Impact of wave soldering
• Partially filled vias

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Workmanship Discrimination Standards
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Standards of Workmanship

• Any training provided should be across the board
  and not just to operators so that everyone
  understands the design and performance intent.
• Discuss both the mounting structure and the
  assembly end product characteristics
• Need for describing the manufacturing target
  condition
• Compares acceptable workmanship as well as
  rejected or process indicator criteria.

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Acceptance

• IPC-A-600G
• Acceptability of Printed Boards
• IPC-A-610D
• Acceptability of Electronic Assemblies
• IPC-WHMA-A-620A
• Requirements Acceptance for Cable Wire
  Harness Assemblies

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Workmanship

• IPC J-STD-001D
• Requirements for Soldering Electrical
  Electronic Assemblies
• IPC-7711A IPC-7721A
• Rework of Electronic Assemblies
• Repair and Modification of PCBs and electronic
  Assemblies

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Materials Inspection
Materials inspection shall consist of
certification, supported by verifying data based
on statistical sampling that all materials which
become a part of the finished product are in
accordance with the printed board procurement
documentation.
Quality Conformance Inspection
Quality conformance inspection shall be performed
using either quality conformance coupons and/or
production boards.
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Acceptance

• Acceptance of product for delivery shall be based
  on product that has passed the testing
  requirements shown in the applicable Performance
  Specification and User defined documentation.

Rejected Lots
If an inspection lot is rejected, the supplier
shall screen out the defective units, i.e. 100
lot inspection, or other documented supplier
quality system.
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Quality and Inspection
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Quality Assessment

• Covers existing standards
• Test method and techniques used to evaluate the
  products that are part of the electronic
  equipment
• Addresses techniques for process control, how
  these should be applied and sampling plan
  characteristics
• Industry best practice criteria for the products
  in question.

33
Process Control Elements

• Key Process Control Variables
• Incoming Material
• Design For Manufacture (DFM)
• Manufacturing Processes
• Training
• Documentation

34
Key Considerations forImproving Yield

• Finer the pitch, more difficult is the
  implementation of design manufacture.
• With reduced pitch, precision becomes more
  intense and process windows tighten
• Lower yield and higher cost if design is not
  precise and processes are not very tightly
  controlled
• With the widespread use of smaller and smaller
  components with finer and finer pitches, the
  problem is simply compounded

35
Common Quality Control Techniques Trial and Error

• Trial Error methods are expensive, time consuming
  and can be frustrating.
• The processes are incredibly high speed.
• They must be performed by machines.
• The equipment must be thoroughly characterized.
• Most large companies have assigned engineers to
  optimize small companies learn as they go.
• Learn as you go is not a real option, since
  revenue or product schedule or both may be
  adversely impacted.
• Fine pitch, BGA, CSP, 0402, 0201, 01005, thin
  PCBs and, no-clean flux compound the yield
  problems

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Design to Improve ManufacturingFirst Pass Yield

• Must understand the interdependency of design,
  incoming materials and manufacturing processes
• Then and only then can we achieve higher yield,
  lower cost and faster time to market
• This requires considerable investment of
  engineering resources at all levels in
• a) Process characterization
• b) Training not just for ENGINEERS but
  MANUFACTURING and support staff
• c) Documentation

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Design For Manufacturability

• DFM is one of the key drivers of manufacturing
  yield

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Design For Manufacturability

• DFM is one of the key drivers of manufacturing
  yield
• Very few circuit board designers have a good
  understanding of manufacturing

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Design For Manufacturability

• DFM is one of the key drivers of manufacturing
  yield
• Very few circuit board designers have a good
  understanding of manufacturing
• So it is common to blame manufacturing for all
  the yield problems since that is where defects
  are discovered

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Incoming Materials Quality

• Garbage in garbage out
• There is no way to improve manufacturing yield if
• Boards and components have poor solderability
• Paste is susceptible to slumping solder balling
• Flux is not compatible with the process, boards
  or components
• Purchasing are unaware of the requirements of the
  above issues.
• Must communicate clearly with suppliers on
  specific process requirements.
• Remember Industry standards are not procurement
  specs
• Demand materials meet your requirements for which
  you are paying.

41
Manufacturing Processes Equipment

• Once the problems in design and incoming
  materials have been addressed, it is time to
  focus on the manufacturing processes and
  equipment to improve yield and expenses
• How should one go about identifying the key
  manufacturing process issues?
• First characterize the process
• Document the details of equipment and
  non-equipment dependent variables that control
  yield. This document serves as the process
  recipe
• Ensure staff are properly trained and competent
  on the use equipment

42
ISO 9000 and Quality

• Most companies claim to have process recipe since
  most of them are now ISO certified
• Unfortunately most ISO 9000 documents do not even
  come close to defining what variables are
  important for yield
• ISO certification is a good thing but very often
  it is more of a marketing tool and not very
  helpful for building products with high yield
• ISO requirement say what you do and do what you
  say as a result most companies dont say much!
• Need detailed recipe to produce quality product

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Meeting ISO but not Quality Requirements

• Use one profile for all products. This is OK for
  ISO but you really need a unique profile for each
  product
• Even an unique profile is not going to help if
  cause is
• Poor solder paste
• Mis-registration or misplacement of components
• Poor handling of components and boards
• Poor solderability
• The process document needs to address all these
  issues in specific detail, even though this is
  more than required for ISO certification

44
Training Documentation

• Having the right design, good quality incoming
  materials and an in-house process document are
  necessary but not sufficient to achieve high
  yield on a consistent basis
• Training of personnel at all levels, from senior
  managers to engineers, operators and support
  staff (i.e. purchasing) is critical for
  addressing all the issues needed to improve yield
  and then profitability

45
Quality Assessment

• Process control is a way of life
• Use of statistics and process control
• Documented expectation and implementation
• Sampling plans for best practice criteria
• Keep operators involved in the process
• Develop meaningful design of experiments

46
AdditionalDocumentation

• SMT Materials Process Specification
• SMT Design For Manufacturability (DFM)
• Surface Mount Equipment Characterization
  (IPC-9850-Not released yet)
• SMT Land Pattern Specification (IPC - 782)
• Adhesive Specification (IPC - 817)
• Solderability Specification (ANSI/J-Std .002/003)
• Need to be developed in-house

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AdditionalDocumentation (continued)

• Solder Fluxes (J-Std -004)
• Solder Paste Specification (J-Std -005)
• Stencil Design Guidelines (IPC 7525)
• Guidelines for Temperature Profiling (IPC-7530)
• Component Handling Series IPC-M-109 (Includes
  J-STD-020/33/35 and IPC-9501/02/03). Formerly
  IPC-786
• SMT Workmanship Standard (J-Std 001/IPC-A- 610)

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• Our thanks go to IPC for providingthe base
  material forthis presentation