The industry's sole guideline on the handling, packaging and storage of printed boards. The guidelines in this document are intended to protect printed boards from contamination, physical damage, solderability degradation and moisture uptake. Consideration is given to packaging material types and methods, production environment, handling and transport of product, and establishing baking profiles for moisture removal. Revision A provides expanded coverage of moisture barrier bags (MBBs), the impact of baking on printed board solderability, ESD issues, mositure concerns for etched cores and composites, desiccant material and HIC cards, and example flowdowns of packaging and handling requirements.
Historically, the printed board industry has relied on military specifications and guidelines to define packaging methods to preserve the quality and reliability of printed boards during shipment and storage. However, many of these documents are obsolete, incomplete, do not address lead-free assembly processes, or do not cover newer laminates or final finishes. Additionally, the proliferation of alternative final finishes has produced concerns and requirements for printed board packaging and handling to preserve the finish and assure good solderability.
This document provides suggestions for proper handling, packaging materials and methods, environmental conditions, and storage for printed boards. These guidelines are intended to protect printed boards from contamination, physical damage, solderability degradation, electrostatic discharge (ESD) (when necessary), and moisture uptake. Moisture absorbed in printed board
laminates expands at soldering temperatures, and in some cases, the resulting vapor pressure can cause internal delamination or excessive strain on plated-hole walls and other structures. This is especially challenging with the higher temperatures used for lead-free soldering. This document covers all phases from the manufacture of the bare printed board, through delivery, receiving, stocking, assembly, and soldering. As a guideline, this information is to be used with, and is secondary to, the established requirements in such documents as the IPC-4550 series for alternate final finishes.
The target audience includes those involved in all phases of printed board design, manufacture, assembly, shipping, storage, and possible warranty activities. Information herein has been supplied by all of these functions, as well as the material and equipment suppliers.
1.4 Terms and Definitions
The definition of all terms used herein shall be as specified in IPC-T-50 and as defined in 1.4.1 through 1.4.6.
1.4.1 Humidity Indicator Card (HIC)
A card on which a moisture-sensitive chemical is applied such that it will make a significant, perceptible change in color (hue), typically from blue (dry) to pink (wet) when the indicated relative humidity is exceeded. The HIC is packed inside the moisture-barrier bag (MBB), along with a desiccant, to aid in determining the level of moisture to which the moisture-sensitive devices or printed boards have been subjected.
1.4.2 Moisture Barrier Bag (MBB)
A bag designed to restrict the transmission of water vapor and used to pack moisture sensitive devices. An MBB is made of material with a low WVTR (see 4.2.1).
In sequential lamination, a structure composed of more than two layers that have been laminated together, and which will subsequently be laminated with other layers into a complete printed board.
1.4.4 Water Vapor Transmission Rate (WVTR)
A measure of the permeability of plastic film or metallized plastic film material to moisture, an important rating for moisture barrier bags (MBBs).
1.4.5 Sulfur Free
Chemicals that are unlikely to express corrosive sulfur compounds like H2S or S02.
1.4.6 Dry Packaging
Packaging that consists of desiccant material and a Humidity Indicator Card (HIC) sealed with the printed boards inside a Moisture Barrier Bag (MBB) (See 4.3.1).
2 APPLICABLE DOCUMENTS
IPC-HDBK-001 Handbook and Guide to Supplement J-STD-001
IPC-T-50 Terms and Definitions for Interconnecting and Packaging Electronic Circuits
IPC-A-311 Process Controls for Phototool Generation and Use
IPC-TR-585 Time, Temperature and Humidity Stress of Final Board Finish Solderability