On January 1, 2026, the General Technical Specification for SMT Solder Processes (GB/T 43287-2025), which is under the jurisdiction of the National Technical Committee for Standardization of High-Frequency Components for Electronic Equipment and approved and released by the Ministry of Industry and Information Technology, was officially implemented. Building on the framework of GB/T 3131-2013, this standard puts forward more stringent and verifiable technical requirements for the physical performance characterization, printing adaptability, reflow response characteristics, and long-term service stability of SMT solders in response to actual working conditions such as current high-density interconnection, miniaturized devices, and mass production of automotive-grade boards. It covers all forms of SMT solder categories from Solder Paste and Solder Wire to preformed solder sheets, and simultaneously repeals the lenient clauses in the original 2013 version that are no longer compatible with the automatic calibration capabilities of production lines, such as the ±5°C melting point deviation and the absence of specified viscosity measurement temperature.

The new standard, for the first time, incorporates the solder joint crack propagation rate of SMT solder after 1000 thermal cycles at a peak temperature of 260°C into mandatory type inspection items, explicitly requiring that the failure cycle of BGA package solder joints under temperature variation conditions from -40°C to 125°C must be no less than 850 cycles. This indicator directly responds to the reliability demands of new energy vehicle electronic control modules for PCBA under complex vibration and wide temperature range working conditions. Previously, the industry generally relied on internal enterprise control standards or supplementary clauses of IPC-J-STD-005 for implementation, lacking a unified basis for value traceability, which made it difficult to horizontally compare yield data between different foundries. This national standard upgrade truly enables cross-supply chain reproducibility in the thermomechanical performance evaluation of SMT solders.

In terms of process adaptability, the standard adds a calculation model for the impact of stencil thickness and opening size on solder paste deposition volume, stipulating that the solder paste volume variation coefficient of the pads corresponding to 0.3mm pitch QFN devices must be controlled at ≤12%, which is 3 percentage points stricter than the recommended value in the 2019 industry white paper. It also requires that after 3 hours of continuous printing of solder paste in a constant temperature environment of 25°C, its viscosity attenuation rate must not exceed 18% of the initial value. These parameters are all derived from the measured big data feedback of production lines of leading domestic EMS enterprises in the past three years, rather than deduced under ideal laboratory conditions, reflecting the in-depth understanding of the standard formulators regarding the multiple disturbance factors affecting SMT solder in real production lines, such as temperature and humidity fluctuations, squeegee pressure drift, and stencil wear.

Units participating in the standard revision, including Shennan Circuits, Universal Scientific Industrial, and the Huawei HiSilicon Process Center, simultaneously disclosed that they completed the switch of the solder paste supplier access system for all core production lines in the second half of 2025. Newly introduced SMT solder batches need to additionally provide a Flux residue ion chromatography analysis report issued by a third-party institution and a Tg value thermal expansion coefficient curve. Some customers have listed compliance with GB/T 43287-2025 as a precondition for PPAP submission in procurement agreements, which means that SMT solder has gradually shifted from a traditional auxiliary material role to a key process element affecting the failure rate of complete machines, and its material selection, batch control, and process monitoring are being rapidly embedded into the quality gate process of complete machine manufacturers.

It is worth noting that this standard does not impose mandatory path restrictions on the lead-free route, and still retains the parallel space for multiple technical routes such as Sn-Ag-Cu, Sn-Bi-Cu, and low-silver systems. However, all formulations must pass the newly added thickness gradient detection of the IMC layer on the copper substrate interface to curb the risk of cold soldering and insufficient soldering caused by abnormal growth of intermetallic compounds. This adjustment not only respects the current technical differences of Domestic Solder Paste enterprises in silver content cost control and wetting activity balance, but also forces upstream alloy smelting and flux compounding processes to evolve towards higher-precision coordination.