[{"data":1,"prerenderedAt":64},["ShallowReactive",2],{"blog-moisture-sensitive-devices-msl-handling-en":3},{"title":4,"description":5,"date":6,"lastUpdated":6,"category":7,"image":8,"readingTime":9,"wordCount":10,"timeRequired":11,"htmlContent":12,"faq":13,"tags":29,"slug":33,"sourceLocale":34,"availableLocales":35,"jsonld":40},"Moisture-Sensitive Devices: MSL and Floor-Life Control","Track moisture-sensitive devices from receiving to reflow using component labels, floor-life records and controlled handling of storage or exposure exceptions.","2026-11-04","assembly",null,13,2530,"PT13M","\u003Cp>Moisture-sensitive semiconductor packages need a documented path from receiving through storage, assembly, reflow and any subsequent rework. The controlling information is the \u003Cstrong>specific component’s label, manufacturer instructions and applicable handling procedure\u003C/strong>. Once a sealed moisture-barrier bag is opened, the assembler must account for eligible floor exposure and resolve any uncertainty before reflow.\u003C/p>\n\u003Cp>The risk is internal moisture turning to vapor during soldering. Rapid heating can produce package cracking, delamination or other damage that may not be visible after assembly. A moisture sensitivity level (MSL) identifies a package’s exposure sensitivity under specified conditions; it is not a general property of every device with the same package outline.\u003C/p>\n\u003Cp>This subject differs from \u003Ca href=\"/en/blog/bga-assembly/\">BGA assembly\u003C/a>, which covers placement and solder-joint challenges, and from bare-board storage. A PCBA can require controls for both boards and components, but the limits, records and corrective actions are not automatically interchangeable.\u003C/p>\n\u003Ch2>Why moisture matters during reflow\u003C/h2>\n\u003Cp>Many plastic semiconductor packages absorb moisture from the surrounding air. Absorption depends on the package construction, the environment and the duration of exposure. During reflow, that moisture can expand rapidly as the package heats.\u003C/p>\n\u003Cp>Possible consequences include:\u003C/p>\n\u003Cul>\n\u003Cli>Internal delamination between package materials.\u003C/li>\n\u003Cli>Cracking or localized package deformation, sometimes described as “popcorning.”\u003C/li>\n\u003Cli>Damage to internal connections or other reliability weaknesses.\u003C/li>\n\u003Cli>Defects that are not apparent from a normal external visual inspection.\u003C/li>\n\u003C/ul>\n\u003Cp>These mechanisms are among the risks discussed in \u003Ca href=\"/en/blog/electronic-component-failure-modes/\">electronic component failure modes\u003C/a>. Inspection and electrical testing are valuable, but a passing result does not reconstruct a missing exposure history or prove that no moisture-related latent damage exists.\u003C/p>\n\u003Cp>A reflow profile also has its own constraints. The package’s moisture classification does not by itself authorize a particular peak temperature or number of heat cycles. See \u003Ca href=\"/en/blog/reflow-soldering/\">reflow soldering\u003C/a> for the broader thermal process; for a specific part, use its applicable component and assembly requirements.\u003C/p>\n\u003Ch2>What the MSL and floor-life label mean\u003C/h2>\n\u003Cp>The MSL is associated with a particular device and package as classified by the applicable requirements. Read it together with the stated exposure conditions and any temperature, handling or reflow restrictions. Do not substitute an MSL from a similar-looking part, another package variant or an old internal record.\u003C/p>\n\u003Cp>IPC/JEDEC J-STD-020 addresses moisture/reflow sensitivity classification of surface-mount devices. IPC/JEDEC J-STD-033 addresses handling, packing, shipping and use of moisture-sensitive surface-mount devices. The contract and project documentation should identify the applicable editions; manufacturer instructions and approved procedures must also be considered.\u003C/p>\n\u003Cp>Texas Instruments’ \u003Cstrong>Power Module MSL Ratings and Reflow Profiles\u003C/strong>, document \u003Cstrong>SLVA840\u003C/strong>, explains the relationship between MSL, ambient exposure and baking constraints, including constraints that can differ between devices and carriers. It references an older edition of J-STD-033, so its references should not be assumed to determine the edition for a new project.\u003C/p>\n\u003Cp>TI SLVA840 identifies MSL 3 with a 168-hour exposure under specified conditions in its context. That figure is useful for understanding the calculation below, but it is \u003Cstrong>not a blanket allowance for all components\u003C/strong>. Use the applicable label, including its exact environmental conditions, and the approved process for the actual lot.\u003C/p>\n\u003Ch3>Example: cumulative exposure\u003C/h3>\n\u003Cp>Assume a lot’s applicable label permits \u003Cstrong>168 hours under its stated factory conditions\u003C/strong>, and the approved procedure treats both logged intervals as eligible floor exposure under those conditions:\u003C/p>\n\u003Ctable>\n\u003Cthead>\n\u003Ctr>\n\u003Cth>Exposure record\u003C/th>\n\u003Cth align=\"right\">Time\u003C/th>\n\u003C/tr>\n\u003C/thead>\n\u003Ctbody>\u003Ctr>\n\u003Ctd>First exposure interval\u003C/td>\n\u003Ctd align=\"right\">48 h\u003C/td>\n\u003C/tr>\n\u003Ctr>\n\u003Ctd>Second exposure interval\u003C/td>\n\u003Ctd align=\"right\">36 h\u003C/td>\n\u003C/tr>\n\u003Ctr>\n\u003Ctd>Total logged exposure\u003C/td>\n\u003Ctd align=\"right\">48 h + 36 h = \u003Cstrong>84 h\u003C/strong>\u003C/td>\n\u003C/tr>\n\u003Ctr>\n\u003Ctd>Nominal remaining allowance before reflow\u003C/td>\n\u003Ctd align=\"right\">168 h − 84 h = \u003Cstrong>84 h\u003C/strong>\u003C/td>\n\u003C/tr>\n\u003C/tbody>\u003C/table>\n\u003Cp>The remaining 84 hours is nominal: it assumes there were no other chargeable exposures and that the recorded conditions and intervals are accepted under the applicable procedure. Time spent in dry storage or a repacked bag must be treated as the approved procedure specifies. \u003Cstrong>Repacking does not automatically reset the exposure clock.\u003C/strong>\u003C/p>\n\u003Cp>If the lot experienced hotter or more humid conditions, missing records or an excursion, do not apply this simple subtraction as a disposition. Place the material on hold for an approved assessment.\u003C/p>\n\u003Ch2>Receiving: preserve the evidence in the bag\u003C/h2>\n\u003Cp>A dry-packed component lot typically arrives in a moisture-barrier bag with a label, desiccant and a humidity indicator card (HIC). The manufacturer’s packaging instructions and the applicable procedure govern what must be present and how it is evaluated.\u003C/p>\n\u003Cp>At receiving, record enough information to connect the unopened package to the later assembly record:\u003C/p>\n\u003Cul>\n\u003Cli>Manufacturer, part number, package identification and MSL.\u003C/li>\n\u003Cli>Lot, batch or other traceability identifiers, plus quantity and carrier type.\u003C/li>\n\u003Cli>Labelled floor-life conditions and any stated reflow or handling restrictions.\u003C/li>\n\u003Cli>Bag seal date, if supplied, and other applicable packing or shelf-life information.\u003C/li>\n\u003Cli>Receipt date and the condition of the bag, seals and labels.\u003C/li>\n\u003Cli>Applicable documentation or revision used to accept the lot.\u003C/li>\n\u003Cli>Any damage, missing information or discrepancy, together with its disposition.\u003C/li>\n\u003C/ul>\n\u003Cp>Inspect the outside of the bag without opening it merely to complete a routine receiving record, unless the approved process requires otherwise. A puncture, failed seal, missing label or untraceable lot should trigger the designated hold process, not an assumption that the components are acceptable.\u003C/p>\n\u003Cp>When the bag is opened for use, check and document the HIC and packaging contents as required by the applicable instructions. The card is an indicator to be interpreted under that procedure, not a universal pass/fail instrument with one criterion for every product. If the indication is unacceptable or cannot be interpreted, hold the lot for assessment. Desiccant presence alone does not establish that the contents are dry.\u003C/p>\n\u003Cp>\u003Cimg src=\"/assets/blogs/moisture-sensitive-devices-msl-handling/humidity-indicator-card-example.webp\" alt=\"Example six-spot humidity indicator card with printed relative humidity values\">\u003C/p>\n\u003Cp>Image: \u003Ca href=\"https://commons.wikimedia.org/wiki/File:6_Spot_Humidity_Indicator_Card.jpg\">6 Spot Humidity Indicator Card\u003C/a>, by Egandolfo, licensed under \u003Ca href=\"https://creativecommons.org/licenses/by-sa/3.0/\">CC BY-SA 3.0\u003C/a>; converted to WebP. This external example is not a HILPCB site photograph or actual lot condition. Values and instructions on the card apply to that specific card, not as universal acceptance criteria.\u003C/p>\n\u003Ch2>Start, track and reconcile floor exposure\u003C/h2>\n\u003Cp>A reliable exposure record links each opening and subsequent movement to the actual component lot. In a typical process, the opening of the sealed bag initiates tracking under the applicable procedure. Confirm the event that starts the clock for the particular material and document it.\u003C/p>\n\u003Cp>The log should make it possible to answer:\u003C/p>\n\u003Col>\n\u003Cli>\u003Cstrong>Which components?\u003C/strong> Record the part number, lot and quantities, including any split reels or trays.\u003C/li>\n\u003Cli>\u003Cstrong>When exposed?\u003C/strong> Record the opening time and each subsequent exposure interval.\u003C/li>\n\u003Cli>\u003Cstrong>Under what conditions?\u003C/strong> Record or reference the environmental monitoring information required by the approved procedure.\u003C/li>\n\u003Cli>\u003Cstrong>Where did they go?\u003C/strong> Identify line-side staging, assembly, approved dry storage, repacking or transfer to another operation.\u003C/li>\n\u003Cli>\u003Cstrong>What remains?\u003C/strong> Record cumulative chargeable exposure and the remaining allowance, or flag the balance as unknown.\u003C/li>\n\u003Cli>\u003Cstrong>What happened next?\u003C/strong> Link the lot to the assembled boards, reflow event, return to stock or authorized disposition.\u003C/li>\n\u003C/ol>\n\u003Cp>A lot may be opened for setup, returned to storage and opened again. The exposure calculation must account for all chargeable intervals rather than treating each opening as a fresh allowance. If a reel is split, each resulting quantity needs a traceable history; otherwise, the exposure balance can be lost during routine material handling.\u003C/p>\n\u003Cp>The required controls extend beyond placement. Coordinate staging and production so that applicable exposure is accounted for through the relevant reflow operation. Components already mounted on a board may still require protection while the board waits for reflow or moves between operations.\u003C/p>\n\u003Ch3>Dry storage and repacking\u003C/h3>\n\u003Cp>Approved dry storage or repacking can be part of an exposure-control process, but neither action should be described as an automatic reset. The applicable standard, component instructions and approved procedure determine whether time in a particular storage condition is treated differently and what records are required.\u003C/p>\n\u003Cp>When moving material into controlled storage, record the transfer time, quantity, lot identity and exposure balance to that point. Record its removal as well. If repacking is authorized, preserve the identity and history with the new package rather than replacing the original history with a new bag date.\u003C/p>\n\u003Cp>If storage conditions were not maintained or cannot be demonstrated, the affected interval needs assessment. Do not silently classify it as protected time.\u003C/p>\n\u003Ch2>Decision table for common handling situations\u003C/h2>\n\u003Ctable>\n\u003Cthead>\n\u003Ctr>\n\u003Cth>Situation\u003C/th>\n\u003Cth>Immediate action\u003C/th>\n\u003Cth>Information needed for disposition\u003C/th>\n\u003C/tr>\n\u003C/thead>\n\u003Ctbody>\u003Ctr>\n\u003Ctd>Intact, identified dry pack received\u003C/td>\n\u003Ctd>Record receipt and store under the applicable instructions\u003C/td>\n\u003Ctd>Part and lot, label, seal date if supplied, bag condition and applicable packing requirements\u003C/td>\n\u003C/tr>\n\u003Ctr>\n\u003Ctd>Bag opened for production\u003C/td>\n\u003Ctd>Start or continue the approved exposure record\u003C/td>\n\u003Ctd>Opening time, MSL, labelled conditions, lot and environmental record\u003C/td>\n\u003C/tr>\n\u003Ctr>\n\u003Ctd>Partial lot returned to storage\u003C/td>\n\u003Ctd>Maintain lot identity and record transfer\u003C/td>\n\u003Ctd>Cumulative exposure, quantity, storage conditions and approved treatment of storage time\u003C/td>\n\u003C/tr>\n\u003Ctr>\n\u003Ctd>Bag damage, missing label or questionable HIC\u003C/td>\n\u003Ctd>Hold the affected material\u003C/td>\n\u003Ctd>Packaging evidence, manufacturer instructions, traceability and approved assessment\u003C/td>\n\u003C/tr>\n\u003Ctr>\n\u003Ctd>Exposure limit may have been exceeded, or history is unknown\u003C/td>\n\u003Ctd>Hold before further heat exposure\u003C/td>\n\u003Ctd>All available timestamps and conditions, affected quantities, applicable recovery options and authorization\u003C/td>\n\u003C/tr>\n\u003Ctr>\n\u003Ctd>Baking is being considered\u003C/td>\n\u003Ctd>Do not bake until the process is approved\u003C/td>\n\u003Ctd>Device and carrier instructions, allowable cycle, equipment method and required records\u003C/td>\n\u003C/tr>\n\u003Ctr>\n\u003Ctd>Board requires rework\u003C/td>\n\u003Ctd>Assess both moisture and thermal history\u003C/td>\n\u003Ctd>Component exposure, prior reflows, rework method, device limits and board-specific instructions\u003C/td>\n\u003C/tr>\n\u003C/tbody>\u003C/table>\n\u003Cp>The table is a routing aid, not a replacement for the project’s approved handling procedure.\u003C/p>\n\u003Ch2>Excursions, unknown exposure and baking\u003C/h2>\n\u003Cp>An excursion is a decision point, not an invitation to guess. Examples include an unrecorded opening time, an environmental condition outside the stated basis, a damaged bag discovered after receipt or a lot found with an unreliable exposure balance. Identify and segregate the affected quantity, preserve the available evidence and obtain an authorized disposition before reflow or another relevant heat operation.\u003C/p>\n\u003Cp>The disposition may involve manufacturer guidance, the applicable standard and the agreed engineering or quality authority. Depending on the case, it could call for a permitted recovery process, further investigation or rejection. A visual check of an apparently intact package is not a substitute for that decision.\u003C/p>\n\u003Ch3>Baking is component- and carrier-specific\u003C/h3>\n\u003Cp>Baking can be a permitted recovery method for some moisture-sensitive devices, but it is not a universal corrective action. There is no safe generic bake time or temperature for every component, reel, tray or tube.\u003C/p>\n\u003Cp>Before authorizing a bake, establish:\u003C/p>\n\u003Cul>\n\u003Cli>Whether the device manufacturer permits it and under what conditions.\u003C/li>\n\u003Cli>Whether the \u003Cstrong>actual carrier\u003C/strong> can withstand the proposed process.\u003C/li>\n\u003Cli>Whether components must be transferred to an approved carrier.\u003C/li>\n\u003Cli>Whether the proposed conditions affect solderability, packaging or other requirements.\u003C/li>\n\u003Cli>Which approved procedure, equipment and records apply.\u003C/li>\n\u003Cli>Who has authority to release the lot afterward.\u003C/li>\n\u003C/ul>\n\u003Cp>Microchip’s \u003Cstrong>MSL Communication\u003C/strong> warns that some trays are not bakeable. TI SLVA840 likewise discusses device and carrier-specific baking constraints. A component’s ability to tolerate a process does not establish that its shipping tray or reel can tolerate the same process.\u003C/p>\n\u003Cp>After an authorized bake, record the material identity and quantity, the approved procedure and its revision, the actual cycle information required by that procedure, completion and release authorization. Then establish the subsequent exposure record according to the approved rules. Do not infer a new allowance merely because an oven cycle was performed.\u003C/p>\n\u003Ch2>Reflow, inspection and rework\u003C/h2>\n\u003Cp>Before reflow, the assembler should be able to connect each controlled component lot to its exposure status and to the boards on which it was used. The production record should also reference the applicable reflow profile and component thermal limits. Moisture control and thermal-profile control are related, but one does not replace the other.\u003C/p>\n\u003Cp>Post-reflow inspection can identify some package and assembly defects. The appropriate methods depend on the design and inspection plan; \u003Ca href=\"/en/blog/pcb-inspection/\">PCB inspection\u003C/a> provides broader context. Neither visual inspection nor a single test method should be represented as proof that an exposure excursion caused no hidden damage.\u003C/p>\n\u003Cp>Rework deserves the same discipline. A board returning for localized heating may contain moisture-sensitive packages that have already experienced assembly heat and subsequent ambient exposure. Before rework, review the affected components’ exposure history, permitted thermal history, rework instructions and any approved conditioning requirement. Record the rework and link it to the board and component traceability. Do not assume that a successful first reflow gives unlimited permission for later heating.\u003C/p>\n\u003Ch2>Release and RFQ information\u003C/h2>\n\u003Cp>For procurement, the practical question is not simply whether the parts have an MSL label. It is whether each party can preserve and transfer the information needed for an authorized assembly decision.\u003C/p>\n\u003Cp>Include the following in the release package or request for quotation:\u003C/p>\n\u003Cul>\n\u003Cli>\u003Cstrong>Component identification:\u003C/strong> manufacturer, full part number, package, MSL and applicable label conditions.\u003C/li>\n\u003Cli>\u003Cstrong>Lot and packaging:\u003C/strong> quantities, lot identifiers, carrier type, bag condition, seal date if available, and any known prior openings.\u003C/li>\n\u003Cli>\u003Cstrong>Exposure history:\u003C/strong> timestamps, cumulative chargeable exposure, environmental records or a clear statement that history is unknown.\u003C/li>\n\u003Cli>\u003Cstrong>Applicable requirements:\u003C/strong> J-STD-020 and J-STD-033 editions specified by contract, component instructions, approved internal procedures and any conflict-resolution route.\u003C/li>\n\u003Cli>\u003Cstrong>Storage and recovery:\u003C/strong> requirements for dry storage, repacking, excursion review and any authorized bake process, including carrier restrictions.\u003C/li>\n\u003Cli>\u003Cstrong>Assembly plan:\u003C/strong> allocation of component lots to boards, intended reflow and rework constraints, and required traceability.\u003C/li>\n\u003Cli>\u003Cstrong>Release evidence:\u003C/strong> records and approvals the receiving party needs before material can be used or returned to stock.\u003C/li>\n\u003Cli>\u003Cstrong>Disposition contacts:\u003C/strong> the named project roles authorized to assess exceptions and release held material.\u003C/li>\n\u003C/ul>\n\u003Cp>Assign responsibilities explicitly. A component supplier may provide original packaging, labels and manufacturer documentation; the customer or material owner should disclose known prior handling; and the assembly party should record the operations it performs under the agreed process. Who monitors conditions, retains records, authorizes recovery and accepts exceptions should be settled in the project agreement—not assumed from a purchase order.\u003C/p>\n\u003Cp>For a project involving supplied or procured components, review the scope of \u003Ca href=\"/en/products/smt-assembly/\">SMT assembly\u003C/a> or \u003Ca href=\"/en/products/turnkey-assembly/\">turnkey assembly\u003C/a>, then identify the required moisture-control responsibilities in the agreement. Submit the part and exposure information with a \u003Ca href=\"/en/quote/\">quote request\u003C/a>, or \u003Ca href=\"/en/contact/\">contact HILPCB\u003C/a> to discuss an unresolved material-history requirement.\u003C/p>\n\u003Cdiv data-component=\"BlogQuickQuoteInline\">\u003C/div>\n\u003C!-- faq:start -->\n\u003Ch2>Frequently Asked Questions\u003C/h2>\n\u003Ch3>Does opening a moisture-barrier bag always start a new full floor life?\u003C/h3>\n\u003Cp>No. Start or continue the exposure record as required by the applicable procedure. A previously opened lot may already have accumulated exposure.\u003C/p>\n\u003Ch3>Is every MSL 3 device allowed 168 hours on the factory floor?\u003C/h3>\n\u003Cp>Do not assume so without checking the applicable label and conditions. The cited 168-hour example is tied to stated environmental conditions and does not override device-specific instructions.\u003C/p>\n\u003Ch3>Does putting a reel back in a sealed bag reset its clock?\u003C/h3>\n\u003Cp>Not automatically. Account for the previous exposure and treat the repacked storage period according to the approved procedure.\u003C/p>\n\u003Ch3>Can any moisture-sensitive component be baked in its original tray?\u003C/h3>\n\u003Cp>No. Device and carrier limits must both permit the proposed process; some trays are not bakeable.\u003C/p>\n\u003Ch3>What should happen when the exposure history is unknown?\u003C/h3>\n\u003Cp>Hold the affected material before further heat exposure and obtain an authorized disposition using the available records, manufacturer instructions and applicable procedure.\u003C/p>\n\u003C!-- faq:end -->\n\u003Csection class=\"related-links\" aria-label=\"Related\">\u003Ch3>Related links\u003C/h3>\u003Cul>\u003Cli>\u003Ca href=\"/en/blog/bga-assembly/\">BGA Assembly: Complete Guide to Ball Grid Array PCB Assembly Process\u003C/a>\u003C/li>\u003Cli>\u003Ca href=\"/en/blog/electronic-component-failure-modes/\">Electronic Component Failure Modes: Types, Causes and Diagnosis\u003C/a>\u003C/li>\u003Cli>\u003Ca href=\"/en/blog/reflow-soldering/\">Reflow Soldering: Process Stages, Temperatures and Reflow vs Wave Soldering\u003C/a>\u003C/li>\u003Cli>\u003Ca href=\"/en/blog/pcb-inspection/\">PCB Inspection Services: AOI, X-Ray, and Quality Control Solutions\u003C/a>\u003C/li>\u003Cli>\u003Ca href=\"/en/products/smt-assembly/\">SMT assembly\u003C/a>\u003C/li>\u003Cli>\u003Ca href=\"/en/products/turnkey-assembly/\">turnkey assembly\u003C/a>\u003C/li>\u003Cli>\u003Ca href=\"/en/quote/\">quote request\u003C/a>\u003C/li>\u003C/ul>\u003C/section>",[14,17,20,23,26],{"question":15,"answer":16,"answerText":16},"Does opening a moisture-barrier bag always start a new full floor life?","No. Start or continue the exposure record as required by the applicable procedure. A previously opened lot may already have accumulated exposure.",{"question":18,"answer":19,"answerText":19},"Is every MSL 3 device allowed 168 hours on the factory floor?","Do not assume so without checking the applicable label and conditions. The cited 168-hour example is tied to stated environmental conditions and does not override device-specific instructions.",{"question":21,"answer":22,"answerText":22},"Does putting a reel back in a sealed bag reset its clock?","Not automatically. Account for the previous exposure and treat the repacked storage period according to the approved procedure.",{"question":24,"answer":25,"answerText":25},"Can any moisture-sensitive component be baked in its original tray?","No. Device and carrier limits must both permit the proposed process; some trays are not bakeable.",{"question":27,"answer":28,"answerText":28},"What should happen when the exposure history is unknown?","Hold the affected material before further heat exposure and obtain an authorized disposition using the available records, manufacturer instructions and applicable procedure.",[30,31,32],"MSL","moisture sensitive devices","floor life","moisture-sensitive-devices-msl-handling","en",[34,36,37,38,39],"de","cn","fr","ru",{"blog":41,"breadcrumb":50},{"@context":42,"@type":43,"headline":4,"description":5,"url":44,"datePublished":6,"dateModified":6,"timeRequired":11,"keywords":45,"articleSection":7,"author":46,"publisher":49},"https://schema.org","BlogPosting","https://hilpcb.com/en/blog/moisture-sensitive-devices-msl-handling/","MSL, moisture sensitive devices, floor life",{"@type":47,"name":48},"Organization","HILPCB",{"@type":47,"name":48},{"@context":42,"@type":51,"itemListElement":52},"BreadcrumbList",[53,58,62],{"@type":54,"position":55,"name":56,"item":57},"ListItem",1,"Home","https://hilpcb.com/",{"@type":54,"position":59,"name":60,"item":61},2,"Blog","https://hilpcb.com/en/blog/",{"@type":54,"position":63,"name":33,"item":44},3,1794062105287]