Trapped moisture inside an IC package can crack the component during reflow soldering. Sometimes this can be violent enough to pop the casing apart.<\/p>\n\n\n\n
MSL baking is the controlled heating process that removes that moisture before assembly, governed by the JEDEC MSL standard (IPC\/JEDEC J-STD-033). When you’re assembling moisture-sensitive surface-mount devices, knowing when and how to bake components before reflow is the difference between reliable boards<\/a> and costly field failures.<\/p>\n\n\n\n Get a Quote<\/a>. Just share your temperature range, load size, and airflow needs.<\/p>\n\n\n\n MSL baking is a low-temperature heating process (typically between 40\u00b0C\/104\u00b0F and 125\u00b0C\/257\u00b0F) designed to remove absorbed moisture from electronic component packaging before reflow soldering. The term “MSL” refers to the moisture sensitivity level assigned to a component under IPC\/JEDEC J-STD-020, while the baking procedures themselves are defined in IPC\/JEDEC J-STD-033.<\/p>\n\n\n\n Components sit in a dry, heated laboratory oven<\/a> long enough for trapped water to escape through the package walls without damaging the component or its internal bonds.<\/p>\n\n\n\n Surface-mount components with organic substrates, plastic molding, or epoxy casings absorb small amounts of water vapor from ambient air. That absorbed moisture becomes dangerous during reflow, when temperatures climb past 200\u00b0C\/392\u00b0F in seconds.<\/p>\n\n\n\n The most well-known failure mode is the “popcorn effect.” During reflow, trapped moisture flashes into steam and expands, generating mechanical stress at internal interfaces\u2014between die and substrate, substrate and molding compound. The result ranges from invisible micro-cracks to visible bulging or cracking of the package body.<\/p>\n\n\n\n Moisture also reduces solderability on exposed leads, producing weak joints prone to voiding and oxide growth. Over time, residual moisture promotes corrosion too, particularly on fine-pitch packages like BGAs and QFNs.<\/p>\n\n\n\n The JEDEC MSL standard classifies surface-mount devices into eight sensitivity levels based on how quickly they absorb moisture once removed from sealed packaging. Each level defines a “floor life”, which is the maximum time a component can sit at factory-floor conditions (\u226430\u00b0C\/\u226486\u00b0F \u2013 60% RH) before it needs baking or resealing.<\/p>\n\n\n\n Component manufacturers print the MSL rating on the moisture barrier bag label and include a humidity indicator card inside the packaging per JEDEC moisture bake requirements.<\/p>\n\n\n\n Components need MSL baking whenever they’ve exceeded their rated floor life. Common triggers include:<\/p>\n\n\n\n If the card’s dots are still blue and the floor-life window hasn’t expired, baking isn’t required.<\/p>\n\n\n\n PCBs absorb moisture too. If bare boards sat outside sealed packaging for more than 24\u201348 hours, many assemblers bake them at 105\u2013125\u00b0C (221\u2013257\u00b0F) for two to six hours before reflow.<\/p>\n\n\n\n The IC moisture bake procedure defined in IPC\/JEDEC J-STD-033 provides three temperature tiers. Bake duration depends on MSL rating, package thickness, and exposure severity. The table below covers the most common production scenario: parts that have exceeded floor life by up to 72 hours at \u226430\u00b0C\/\u226486\u00b0F \u2013 60% RH.<\/p>\n\n\n\nWhat is <\/strong>MSL baking<\/strong>?<\/strong><\/h2>\n\n\n\n
Why moisture causes failures in electronics<\/strong><\/h2>\n\n\n\n
What are moisture sensitivity levels?<\/strong><\/h2>\n\n\n\n
When do electronic components need moisture bake-out?<\/strong><\/h2>\n\n\n\n
Standard <\/strong>MSL baking<\/strong> temperatures and times<\/strong><\/h2>\n\n\n\n