IEC 60749-20-1:2019

Overview

IEC 60749-20-1:2019 is an IEC standard that defines standardized handling, packing, labelling and shipping procedures for surface-mount devices (SMDs) that are sensitive to the combined effects of moisture and soldering heat. It applies to all devices exposed to bulk solder reflow during PCB assembly-particularly plastic‑encapsulated, process‑sensitive and other moisture‑permeable materials (epoxies, silicones, etc.). The objective is to prevent moisture-induced damage during reflow that can degrade yield and long‑term reliability.

Key topics and technical requirements

• Scope and applicability: Covers SMDs classified to IEC 60749-20 levels and devices used in mass reflow processes.
• Dry packing (MBBs): Requirements for moisture barrier bags (MBBs), desiccants, sealing, labeling and minimum shelf life from the seal date to enable safe, damage‑free reflow.
• Drying and baking: Approved drying options, bake tables and precautions to remove absorbed moisture prior to sealing or reflow. Annex D provides guidance on derivation of bake tables.
• Floor life and use: Rules for floor life start, clock resetting/pausing, safe storage categories, and reflow categories including limits on multiple reflow passes.
• Inspection and indicators: Incoming bag inspection, humidity indicator cards (HIC) testing and interpretation. Annex C is a normative method for colorimetric testing of HICs.
• Labels and symbols: Standardized MSID (Moisture Sensitive Identification) labels, caution labels and information required on packaging (Annex A).
• Rework and board baking: Guidance on component removal, rework and baking of populated boards (informative Annex B).
• Alignment with industry practices: Updates to align subclauses with IPC/JEDEC J‑STD‑033C, including aqueous cleaning and dry‑pack precautions.

Practical applications and users

Who benefits:

• SMD manufacturers and semiconductor packaging teams
• PCB assemblers and contract manufacturers (CMs)
• Quality, reliability and materials engineers
• Supply chain, packaging, logistics and warehouse personnel
• Failure analysis and board rework technicians

Practical uses:

• Establishing a dry‑pack and shipping process to ensure minimum shelf life and safe reflow
• Creating incoming inspection procedures using HICs
• Determining bake times and storage rules to reset or preserve floor life
• Standardizing labels and documentation for moisture‑sensitive devices in transit

Related standards

• IEC 60749-20 (classification of moisture sensitivity levels)
• IPC/JEDEC J‑STD‑033 (industry practices for moisture/reflow sensitive SMDs)

By following IEC 60749-20-1:2019, organizations can reduce moisture-related assembly failures, standardize handling and packaging practices, and improve yield and reliability for moisture‑sensitive SMDs.