IEC 60749-20-1:2009

FOREWORD
INTRODUCTION
1 Scope
2 Normative references
3 Terms and definitions
4 General applicability and reliability considerations
  4.1 Assembly processes
      4.1.1 Mass reflow
      4.1.2 Localized heating
      4.1.3 Socketed components
      4.1.4 Point-to-point soldering
  4.2 Reliability
5 Dry packing
  5.1 Requirements
  5.2 Drying of SMDs and carrier materials before being
      sealed in MBBs
      5.2.1 Drying requirements - level A2
      5.2.2 Drying requirements - levels B2a to B5a
      5.2.3 Drying requirements - carrier materials
      5.2.4 Drying requirements - other
      5.2.5 Excess time between bake and bag
  5.3 Dry pack
      5.3.1 Description
      5.3.2 Materials
      5.3.3 Labels
      5.3.4 Shelf life
6 Drying
  6.1 Drying options
  6.2 Post exposure to factory ambient
      6.2.1 Floor life clock
      6.2.2 Any duration exposure
      6.2.3 Short duration exposure
  6.3 General considerations for baking
      6.3.1 High-temperature carriers
      6.3.2 Low-temperature carriers
      6.3.3 Paper and plastic container items
      6.3.4 Bakeout times
      6.3.5 ESD protection
      6.3.6 Reuse of carriers
      6.3.7 Solderability limitations
7 Use
  7.1 Floor life clock start
  7.2 Incoming bag inspection
      7.2.1 Upon receipt
      7.2.2 Component inspection
  7.3 Floor life
  7.4 Safe storage
      7.4.1 Safe storage categories
      7.4.2 Dry pack
      7.4.3 Dry atmosphere cabinet
  7.5 Reflow
      7.5.1 Reflow categories
      7.5.2 Opened MBB
      7.5.3 Reflow temperature extremes
      7.5.4 Additional thermal profile parameters
      7.5.5 Multiple reflow passes
      7.5.6 Maximum reflow passes
  7.6 Drying indicators
      7.6.1 Drying requirements
      7.6.2 Excess humidity in the dry pack
      7.6.3 Floor life or ambient temperature/humidity exceeded
      7.6.4 Level B6 SMDs
Annex A (normative) Symbol and labels for moisture-sensitive
        devices
Annex B (informative) Board rework
Annex C (informative) Derating due to factory environmental
        conditions
Bibliography

IEC 60749-20-1:2009 applies to all non-hermetic SMD packages which are subjected to reflow solder processes and which are exposed to the ambient air. The purpose of this document is to provide SMD manufacturers and users with standardized methods for handling, packing, shipping, and use of moisture/reflow sensitive SMDs which have been classified to the levels defined in IEC 60749-20. These methods are provided to avoid damage from moisture absorption and exposure to solder reflow temperatures that can result in yield and reliability degradation. By using these procedures, safe and damage-free reflow can be achieved, with the dry packing process, providing a minimum shelf life capability in sealed dry-bags from the seal date.