IPC/JEDEC J-STD-020C ASSOCIATION CONNECTING ELECTRONICS INDUSTRIES ® Moisture/Reflow Sensitivity Classification for Nonhermetic Solid State Surface Mount Devices A joint standard developed by the IPC Plastic Chip Carrier Cracking Task Group (B-10a) and the JEDEC JC-14.1 Committee on Reliability Test Methods for Packaged Devices Supersedes: IPC/JEDEC J-STD-020B July 2002 IPC/JEDEC J-STD-020A April 1999 J-STD-020 - October 1996 JEDEC JESD22-A112 IPC-SM-786A - January 1995 IPC-SM-786 - December 1990 Users of this standard are encouraged to participate in the development of future revisions. Contact: JEDEC Solid State Technology Association 2500 Wilson Boulevard Arlington, VA 22201-3834 Phone (703) 907-7500 Fax (703) 907-7501 IPC 2215 Sanders Road Northbrook, IL 60062-6135 Phone (847) 509-9700 Fax (847) 509-9798 July 2004 IPC/JEDEC J-STD-020C Table of Contents 1 1.1 1.2 2 PURPOSE ................................................................. 1 Scope .................................................................... 1 Background .......................................................... 1 APPLICABLE DOCUMENTS ................................... 1 2.1 2.2 JEDEC Solid State Technology Associaton ........ 1 IPC ....................................................................... 2 2.3 Joint Industry Standards ...................................... 2 3 APPARATUS ............................................................. 2 3.1 3.2 Temperature Humidity Chambers ....................... 2 Solder Reflow Equipment ................................... 2 3.2.1 3.2.2 Full Convection (Preferred) ................................. 2 Infrared ................................................................. 2 3.3 3.4 3.4.1 3.4.2 Ovens ................................................................... Microscopes ......................................................... Optical Microscope .............................................. Scanning Acoustic Microscope ........................... 3.5 3.6 Cross-Sectioning .................................................. 2 Electrical Test ...................................................... 2 3.7 Weighing Apparatus (Optional) ........................... 2 4 4.1 4.2 5 5.1 5.1.1 2 2 2 2 CLASSIFICATION/RECLASSIFICATION ................. 3 CRITERIA .................................................................. 6 6 6.1 6.2 Failure Criteria ..................................................... 6 Criteria Requiring Further Evaluation ................ 7 6.2.1 6.3 Delamination ........................................................ 7 Failure Verification .............................................. 8 7 MOISTURE/REFLOW SENSITIVITY CLASSIFICATION ..................................................... 8 8 OPTIONAL WEIGHT GAIN/LOSS ANALYSIS ........ 8 8.1 8.2 Weight Gain ......................................................... 8 Absorption Curve ................................................. 8 8.2.1 8.2.2 8.2.3 8.2.4 8.3 8.3.1 Read Points .......................................................... Dry Weight ........................................................... Moisture Soak ...................................................... Readouts ............................................................... Desorption Curve ................................................. Read Points .......................................................... 8.3.2 8.3.3 Baking .................................................................. 9 Readouts ............................................................... 9 9 8 8 8 8 9 9 ADDITIONS AND EXCEPTIONS ............................. 9 Annex A ..................................................................... 10 Compatibility with Pb-Free Rework ................... 3 Reclassification .................................................... 3 PROCEDURE ............................................................ 4 5.1.2 5.2 5.3 5.4 5.5 5.6 Sample Requirements .......................................... Reclassification (Qualified Package Without Additional Reliability Testing) ............................ Classification/Reclassification and Rework ........ Initial Electrical Test ............................................ Initial Inspection .................................................. Bake ..................................................................... Moisture Soak ...................................................... Reflow .................................................................. 5.7 5.8 Final External Visual ........................................... 5 Final Electrical Test ............................................. 5 5.9 Final Acoustic Microscopy .................................. 5 Figures 4 4 4 4 4 5 5 5 Figure 5-1 Classification Reflow Profile ................................ 6 Tables Table 4-1 SnPb Eutectic Process – Package Peak Reflow Temperatures .......................................... 3 Table 4-2 Pb-free Process – Package Classification Reflow Temperatures .......................................... 3 Table 5-1 Moisture Sensitivity Levels .................................. 5 Table 5-2 Classification Reflow Profiles .............................. 6 v July 2004 IPC/JEDEC J-STD-020C Moisture/Reflow Sensitivity Classification for Nonhermetic Solid State Surface Mount Devices 1 PURPOSE The purpose of this standard is to identify the classification level of nonhermetic solid state surface mount devices (SMDs) that are sensitive to moisture-induced stress so that they can be properly packaged, stored, and handled to avoid damage during assembly solder reflow attachment and/or repair operations. This standard may be used to determine what classification/preconditioning level should be used for SMD package qualification. Passing the criteria in this test method is not sufficient by itself to provide assurance of long-term reliability. This classification procedure applies to all nonhermetic solid state Surface Mount Devices (SMDs) in packages, which, because of absorbed moisture, could be sensitive to damage during solder reflow. The term SMD as used in this document means plastic encapsulated surface mount packages and other packages made with moisture-permeable materials. The categories are intended to be used by SMD producers to inform users (board assembly operations) of the level of moisture sensitivity of their product devices, and by board assembly operations to ensure that proper handling precautions are applied to moisture/reflow sensitive devices. If no major changes have been made to a previously qualified SMD package, this method may be used for reclassification according to 4.2. 1.1 Scope This standard cannot address all of the possible component, board assembly and product design combinations. However, the standard does provide a test method and criteria for commonly used technologies. Where uncommon or specialized components or technologies are necessary, the development should include customer/manufacturer involvement and the criteria should include an agreed definition of product acceptance. SMD packages classified to a given moisture sensitivity level by using Procedures or Criteria defined within any previous version of J-STD-020, JESD22-A112 (rescinded), IPC-SM-786 (superseded) do not need to be reclassified to the current revision unless a change in classification level or a higher peak reflow temperature is desired. Note: If the procedures in this document are used on packaged devices that are not included in this specification’s scope, the failure criteria for such packages must be agreed upon by the device supplier and their end user. 1.2 Background The vapor pressure of moisture inside a nonhermetic package increases greatly when the package is exposed to the high temperature of solder reflow. Under certain conditions, this pressure can cause internal delamination of the packaging materials from the die and/or leadframe/substrate, internal cracks that do not extend to the outside of the package, bond damage, wire necking, bond lifting, die lifting, thin film cracking, or cratering beneath the bonds. In the most severe case, the stress can result in external package cracks. This is commonly referred to as the ‘‘popcorn’’ phenomenon because the internal stress causes the package to bulge and then crack with an audible ‘‘pop.’’ SMDs are more susceptible to this problem than through-hole parts because they are exposed to higher temperatures during reflow soldering. The reason for this is that the soldering operation must occur on the same side of the board as the SMD device. For through-hole devices, the soldering operation occurs under the board that shields the devices from the hot solder. 2 APPLICABLE DOCUMENTS 2.1 JEDEC Solid State Technology AssociatIon1 JESD22-A120 Test Method for the Measurement of Moisture Diffusivity and Water Solubility in Organic Materials Used in Integrated Circuits JESD22-A113 Preconditioning Procedures of Plastic Surface Mount Devices Prior to Reliability Testing JESD 47 Stress Test Driven Qualification Specification JESD-625 Requirements for Handling Electrostatic Discharge Sensitive (ESD) Devices 1. www.jedec.org 1