Analyse du processus d'assemblage des cartes de circuits imprimés dans 2026
Dans 2026, L'ensemble de cartes de circuit imprimé (PCBA) industry is undergoing an unprecedented transformation. It is no longer merely about the traditional process of soldering components onto circuit boards, but has evolved into a precision intelligent manufacturing industry deeply integrating artificial intelligence (IA) puissance de calcul, advanced packaging technologies, and full-process digitalization. From ultra-high-layer backplanes driving NVIDIA Rubin architecture GPUs to 01005 components as small as grains of sand in smart glasses, every stage of PCBA is pushing the limits of physics and manufacturing processes. This article provides an in-depth analysis of the core processes, technological trends, and current industry challenges of PCBA in 2026.
Core Driving Forces of PCBA in 2026
Entering 2026, the global PCBA market continues to expand under the strong momentum of AI. According to market research data, le mondial Assemblage PCB market was valued at over $100 milliards en 2025 and is projected to grow at a compound annual growth rate (TCAC) de 5.5% à travers 2035. Behind this growth lie three key driving forces:
D'abord, the upgrade of AI computing infrastructure is the primary engine. To meet the ultra-high computing demands of platforms such as NVIDIA Rubin NVL144/576, PCB technology is undergoing a generational leap. Traditional PCBs are advancing toward ultra-high-layer backplanes with 40–80 layers, with interlayer alignment errors strictly controlled within ±5 μm. En même temps, the large-scale application of M9-grade materials (integrating high-frequency/high-speed resins, HVLP ultra-low profile copper foil, and quartz fiber cloth) marks a qualitative leap in signal transmission efficiency.
Deuxième, edge AI and automotive intelligence are opening new growth opportunities. The rapid growth of terminal devices such as AI smartphones and AI glasses is driving flexible printed circuits (FPCS) to upgrade to 4–6 layers, while substrate-like PCBs (Orthophoniste) are seeing significantly increased adoption in flagship Android devices. In the automotive sector, the proliferation of L3+ autonomous driving is pushing intelligent driving domain controller PCBs to evolve from traditional HDI to hybrid solutions combining “high multilayer + HDI” to meet the stringent requirements of high-computing-power chips such as AI5.
Enfin, the restructuring of the global supply chain and domestic substitution are reshaping the industry landscape. D'une part, AI PCB industry clusters in Southeast Asia are taking shape, becoming key hubs serving North American customers. D'autre part, high-end materials such as quartz fiber cloth (Q cloth) are experiencing sharp price increases due to supply-demand gaps (estimated at 25–30%), and the unit price of high-end drill bits has risen by more than 30%, creating opportunities for manufacturers with core technologies.
Core Process Revolution: From Advanced Packaging to Micro Assembly
Par 2026, the “core processes” of PCBA have extended beyond traditional SMT and are increasingly penetrating into chip-level packaging technologies.
2.1 Integration of Advanced Packaging: CoWoP and Glass Substrates
Dans le passé, packaging and assembly were clearly separated, but in today’s AI server field, this boundary is becoming increasingly blurred. CoWoP (Chip-on-Wafer-on-PCB) technology is expected to formally expand from optical modules into AI server motherboards in 2026. This technology integrates IC substrates with PCBs into a unified structure, essentially applying substrate-like PCB (Orthophoniste) technology to large-size products. It requires PCB manufacturers to possess mSAP (modified semi-additive process) capacités, which is becoming a key competitive advantage for the next generation.
Entre-temps, to address warpage issues, glass core substrates and TGV (Through-Glass Via) technologies are transitioning from laboratory research to industrial validation, aiming to provide better electrical stability and flatness for AI chips.
2.2 Extreme Challenges in SMT: 01005 and POP Adoption
In consumer electronics and IoT sectors, miniaturization remains the dominant trend.
01005 Placement des composants:
With dimensions of only 0.4 mm × 0.2 mm—smaller than a grain of sand—these components require pick-and-place machines to achieve sub-micron optical alignment accuracy and extremely precise nozzle pressure control. Even minor vibrations can lead to tombstoning or misalignment.
POP (Package on Package) Technologie:
With the increasing integration of mobile chips, POP technology—stacking logic chips and memory chips—has become standard. This process requires high-precision secondary alignment and strict temperature control during reflow soldering to prevent defects such as bridging or cold solder joints between upper and lower chips.
In-Depth Analysis of the Full PCBA Process
Étape 1: Material Preparation and Incoming Inspection
Objectif: Ensure all materials meet process requirements.
PCB Incoming Inspection:
Check whether pads are oxidized, whether the solder mask is peeling off, and whether the surface finish (such as ENIG – Electroless Nickel Immersion Gold) is uniform. For high-frequency M9 materials, warpage must also be verified to be less than 0.5%.
Composants:
Batch numbers are scanned and recorded, then verified against the BOM (Sauvetage). For MSDs (Moisture Sensitive Devices), vacuum packaging integrity must be confirmed. If exposure time exceeds limits, baking is required for moisture removal (Par exemple, 125°C for 4–8 hours).
Solder Paste Management:
After removal from refrigeration, solder paste must be brought to room temperature (typiquement 4 heures) and stirred to restore proper viscosity.
Étape 2: Impression de pâte de soudure
Objectif: Accurately transfer solder paste onto PCB pads.
Stencil Installation:
A laser-cut stencil (typically 0.1–0.15 mm thick) is installed according to PCB pad design.
Printing Process:
A squeegee pushes the solder paste at a specific angle and pressure, allowing it to roll and fill stencil apertures, depositing onto pads.
SPI Inspection:
Immediately after printing, 3D solder paste inspection is performed. The system measures volume, hauteur, and area of paste on each pad. If insufficient paste, pontage, or excessive thickness is detected, alarms are triggered or automatic cleaning is initiated.
Étape 3: Top-Side Component Placement
Objectif: Place components onto solder-pasted pads.
Adhesive/Red Glue Process (si nécessaire):
For heavier components on the soudure d'onde side, adhesive is applied first for fixation.
Placement à grande vitesse:
Pick-and-place machines operate at tens of thousands of components per minute, placing micro components such as 01005 (0.4 × 0.2 MM) with ±0.025 mm accuracy using flying alignment technology.
Odd-Shape Component Placement:
General-purpose heads handle larger or irregular components such as BGA, QFN, and connectors. Vision systems capture component leads and PCB fiducial marks, using laser alignment to ensure precise positioning.
Étape 4: Soudeur de reflux (Top Side)
Objectif: Melt solder paste to form metallurgical bonds between components and PCB.
Conveying:
The PCB passes through a reflow oven with multiple independently controlled temperature zones.
Four Temperature Zones:
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Zone de préchauffage: Gradual heating activates flux and evaporates solvents.
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Zone de trempage: Maintains temperature to equalize heat across PCB and components, preventing thermal shock.
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Zone de refusion: Temperature rises rapidly to peak (typically 235–250°C), melting solder paste and forming IMC (Intermetallic Compounds).
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Zone de refroidissement: Rapid cooling forms strong and shiny solder joints.
Atmosphere Control:
For high-density BGA assemblies, nitrogen is often introduced to reduce oxidation and improve soldering yield.
Étape 5: Board Flipping and Bottom-Side Placement
Objectif: Complete component placement on the bottom side.
Board Flipper:
Gently flips the PCB after top-side soldering to prevent heavy components from falling.
Repeat Printing and Placement:
Mesures 2 et 3 are repeated for the bottom side.
Second Reflow:
PCB undergoes another reflow cycle. Fixture design is critical to prevent previously soldered components from detaching.
Étape 6: Selective Wave Soldering (Through-Hole Components)
Objectif: Solder through-hole components such as connectors and transformers.
Insertion:
Components are inserted manually or via automated insertion machines.
Flux Spraying:
A robotic arm with a micro-nozzle applies flux only to required through-hole areas.
Localized Soldering:
The PCB moves over a solder nozzle that sprays molten solder upward, precisely contacting leads and hole walls to complete soldering while protecting SMT components from excessive heat.
Étape 7: Press-Fit and Depaneling
Press-Fit Process:
For certain solderless connectors, hydraulic equipment presses pins into PCB holes, forming airtight connections.
Depaneling:
If the PCB is panelized, routing or laser cutting is used along V-Cuts or mouse bites to separate individual boards.
Étape 8: AOI (Inspection optique automatisée)
Objectif: Detect visual defects.
Position:
Typically performed after reflow soldering.
Principe:
High-resolution cameras capture PCB images and compare them with standard references to detect missing components, désalignement, tombstoning, polarity errors, and solder bridging.
Étape 9: AXI (Inspection automatisée aux rayons X)
Objectif: Inspect hidden solder joints.
Targets:
Components like BGA and QFN with concealed leads.
Inspection des rayons X:
X-rays penetrate the package to detect voids, pontage, circuits ouverts, and cold solder joints. Par 2026, 3D CT scanning is mainstream, enabling layer-by-layer analysis of each solder ball.
Étape 10: TIC (Test en circuit)
Objectif: Tests de performances électriques.
Test de sonde volante:
For prototypes or small batches, probes move across test points to measure open/short circuits and component values (résistance, capacitance, inductance), verifying placement accuracy and component integrity.
Étape 11: FCT (Test fonctionnel)
Objectif: Simulate real operating conditions to verify board functionality.
Power-On Testing:
Dedicated test fixtures power the PCBA and input simulated signals, checking outputs. Examples include verifying power board voltage levels, communication signal waveforms, and AI accelerator performance.
Étape 12: Revêtement conforme
Objectif: Protection and lifespan extension.
Applications:
Électronique automobile, outdoor devices, systèmes de contrôle industriels, etc..
Coating Process:
Automated spraying applies a uniform acrylic, polyurethane, or silicone layer to protect against moisture, poussière, brouillard salin, and chemical contamination.
Étape 13: Burn-In Testing
Objectif: Identify early failures.
Processus:
PCBA units are placed in high-temperature chambers (typically 55–85°C) and powered on for several hours to tens of hours, accelerating the exposure of latent defects.
Étape 14: Final Cleaning, Conditionnement, and Shipment
Nettoyage:
Eco-friendly cleaning agents remove residual flux.
Inspection finale & Conditionnement:
Manual or automated visual inspection is performed, followed by vacuum packaging. Products are placed in anti-static containers, labeled with traceability barcodes, and shipped to customers.
Three PCBA Assembly Technologies: Technologie à travers (Tht), Technologie de montage de surface (Smt), and Hybrid Assembly
Technologie à travers (Tht) Processus d'assemblage
As a classic method in PCB assembly, through-hole technology typically combines manual operations with automated equipment. The overall process includes the following steps:
Étape 1: Insertion de composants
This stage is usually performed manually by experienced technicians. Operators insert various components quickly and accurately into designated holes according to the Conception de PCB files provided by the customer. Pendant ce processus, strict adherence to THT standards is required, such as verifying component polarity and orientation, and preventing interference between components. For electrostatic-sensitive devices like ICs, anti-static protection (Par exemple, wrist straps) must be used to ensure both product quality and component safety.
Étape 2: Inspection and Adjustment
Après l'insertion, the PCB is placed into dedicated carriers, where inspection systems automatically verify component placement and condition. Any misalignment or errors can be corrected before soldering, reducing the risk of defects in subsequent processes.
Étape 3: Soudure d'onde
The PCB then enters the soldering stage. It passes through a wave soldering machine, moving slowly over molten solder at approximately 260°C (500°F), allowing component leads to form reliable connections with pads. After this process, through-hole components are securely fixed onto the PCB.
Technologie de montage de surface (Smt) Processus d'assemblage
Compared with THT, SMT offers significantly higher manufacturing efficiency, characterized by a highly automated process from printing to soldering. The main steps are as follows:
Étape 1: Impression de pâte de soudure
Solder paste is first evenly applied onto PCB pads using a printing machine. Un pochoir (steel mesh) controls the deposition location and volume to ensure precise coverage. Since this step directly impacts soldering quality, many manufacturers perform inspection after printing. If defects are found, cleaning and reprinting are required.
Étape 2: Placement des composants
After printing, the PCB is automatically transferred to the pick-and-place machine. With the adhesive properties of solder paste, components or ICs are accurately placed onto corresponding pads. Components are supplied via tape reels, enabling high-speed and precise automated placement.
Étape 3: Soudeur de reflux
The assembled PCB enters a reflow oven, where solder paste melts at around 260°C, forming solder joints that securely attach surface-mount devices to the PCB.
Hybrid Assembly Technology
With the continuous advancement toward higher integration and miniaturization in electronic products, a single assembly method is no longer sufficient. Aujourd'hui, most PCB assemblies include both through-hole and surface-mount components.
Donc, in practical production, THT and SMT processes are often used in combination. Cependant, since soldering is inherently complex and influenced by multiple factors, properly planning the sequence of these processes is critical, as it directly affects the final product’s quality and reliability.
Conclusion
Transforming a bare PCB into a fully functional PCBA requires more than a dozen, sometimes over twenty, core processes. Dans 2026, this workflow is not only a sequence of physical operations but also a continuous data flow—SPI data, placement coordinates, and reflow temperature profiles for each PCB are recorded, forming a traceable “digital twin.” Understanding this process means understanding the fundamental manufacturing logic of modern electronics.
