PCB · PCB ASSEMBLY · DESIGN · PROCUREMENT AND ACCEPTANCE
Select PCB surface finishes by region according to soldering, contact, and storage requirements. This article compares priorities for HASL, OSP, ENIG, immersion tin, immersion silver, and contact gold. A split-bag opening example explains inventory management, with records for coating-thickness definitions, region boundaries, and soldering-failure troubleshooting.
Read ArticleThermal vias require joint review of hole-wall copper, fill, soldering, and external contact. This article uses hole-wall copper cross-sections and parallel thermal-path calculations to explain the limits of adding vias, with via-array configurations, stencil coordination, and measurement tables for diagnosing solder loss, voids, interface air gaps, and unchanged temperature rise.
Read ArticleEmbedded copper connects high-current or heat-transfer regions through local cross-sections; its capacity cannot be determined from copper weight alone. This article uses cross-section, resistance, and dissipation calculations to illustrate connection bottlenecks, and provides three-dimensional structural inputs, insulation and lamination checks, four-wire voltage-drop measurements, and local hot-spot troubleshooting.
Read ArticleTenting, plugging, filling, and copper capping correspond to different cross-sections; via-in-pad requirements cannot be defined by 'plugging' alone. This article compares hole treatments for preventing solder wicking, planarity, protection, and assembly, uses a hole-volume calculation to illustrate dimensional effects, and provides hole-group tables, inspection methods, and solder-loss troubleshooting.
Read ArticleAn HDI fabrication review must check each microvia group's start and end layers, depth, fill, stacked interfaces, and lamination sequence. This article uses an eight-layer via configuration and an aspect-ratio calculation to explain documentation methods, with checklists for fabrication inputs, representative cross-sections, and fault localization. It distinguishes copper-filled microvias, resin-filled vias, and tented vias.
Read ArticleDistinguish static forming from dynamic bending first. A strain example explains thickness/radius relationships, with transition, coverlay, stiffener, and assembly-route checks. Staged continuity and physical evidence help locate bend-induced opens.
Read ArticlePCB rules must match copper weight, hole types, materials, and tolerances rather than uniformly smaller clearances. Annular-ring/routing-channel examples explain dependencies, with grouped CAD rules, exception closure, and fabrication review, distinguishing manufacturing rules from electrical spacing.
Read ArticleDigital stackup libraries organize inputs, but library names do not replace approved order snapshots. This article distinguishes typical material-class values from specific grades, using revision changes to identify dielectric-thickness, foil, and impedance impacts, with snapshot, difference-review, and repeat-order checks.
Read ArticleSelect PCB thermal structures from the source-to-ambient path. This article compares roles of IMS metal substrates, thermal vias, and embedded copper, locating bottlenecks through series-resistance examples. Insulation, assembly, measurement, and specimen matrices explain why more copper/vias may not reduce temperature.
Read ArticleDetermine HDI order from actual BGA breakout, references, and via layer pairs. This article compares through-hole dogbones, microvia dogbones, and microvias in pads, using routing-width examples to identify bottlenecks. Sequential-lamination, stacking tradeoffs, and verification inputs prevent structure upgrades based only on package pitch.
Read ArticleDeliver manufacturing files as complete revision packages, with shared units/revisions across graphics, drilling, stackup, and notes. Based on Ucamco's transfer guide, this article provides directory examples, receiving checks, coordinate-ratio checks, and old/new attachment conflict handling for traceable engineering closure.
Read ArticleGerber Job provides machine-readable manufacturing attributes but cannot automatically resolve thickness, finish, or layer-order conflicts. A Job/drawing thickness mismatch illustrates attribute comparisons, referenced-file completeness, complete-package reissue, and checksum records, defining partial-implementation boundaries.
Read ArticleHDI structure and low-volume material preparation involve two separate decisions: define via layer pairs and build-up layers, then assess how material availability and substitutions affect validation.
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