IEC 60191-4:2013

FOREWORD
1 Scope
2 Coding system of package outlines for
  semiconductor devices
3 Classification into forms of package
  outlines for semiconductor devices
4 Coding system for semiconductor-device
  packages
5 Coding system of package-outline styles
Annex A (informative) - Examples of descriptive
        coding system application
Annex B (informative) - Derivation and application
        of the descriptive coding system - Common
        package names
Annex C (informative) - Terminology of semiconductor
        package outlines

IEC 60191-4:2013 specifies a method for the designation of package outlines and for the classification of forms of package outlines for semiconductor devices and a systematic method for generating universal descriptive designators for semiconductor device packages. The descriptive designator provides a useful communication tool but has no implied control for assuring package interchangeability. This edition includes the following significant technical changes with respect to the previous edition:
a) Material code "S" is added to indicate a silicon based package.
b) Description of "WL" is added to be used for general use.