mSAP Process Becomes Entry Ticket for High-End PCB as Chiplet Wave Drives FC-BGA Substrate Demand

In 2026, with the comprehensive upgrade of AI computing power hardware, the generational replacement of PCB manufacturing processes and packaging technologies is happening simultaneously. The mSAP, or modified semi-additive process, with its ultra-fine circuit processing capability, is penetrating from an exclusive process in the IC substrate field to high-end PCB across the board, becoming the entry process for high-end computing power hardware. The accelerated popularization of the Chiplet architecture continues to drive FC-BGA substrate demand, pushing packaging substrates to the core position of the AI industry chain.

mSAP: From Substrate Exclusive to High-End PCB Entry Ticket

mSAP, or Modified Semi-Additive Process, is a PCB manufacturing process specially designed for ultra-fine circuits. Unlike the traditional subtractive method of panel plating plus etching, mSAP adopts a process route of about 3 micrometers ultra-thin copper foil plus pattern plating plus quick etching, improving line width and spacing precision to 15 micrometers and below. Line width precision can reach plus or minus 3 micrometers, far better than the plus or minus 8 micrometers of the subtractive method. Copper foil utilization increases from 55 percent to 92 percent. Impedance control precision reaches plus or minus 5 percent, suitable for high-speed signal transmission above 56 Gbps.

The application boundary of mSAP process is expanding rapidly. In the optical module field, as the Rubin series AI chips enter mass production, 1.6T optical modules are gradually becoming standard in AI data centers. The PCB circuit fineness of 1.6T optical modules is comprehensively improved compared with 800G. The traditional HDI line width limit can no longer adapt to 224 Gbps high-speed signals, while mSAP can stably achieve 15 to 20 micrometers ultra-fine circuits, becoming a rigid demand process for high-end high-speed optical modules.

At the packaging architecture level, the release of Nvidia’s CoWoP packaging roadmap in July 2025 became a key turning point. This new architecture cancels the traditional packaging substrate and directly solders the chip module to the high-density PCB motherboard, making mSAP process jump from an auxiliary technology to a core bottleneck in AI hardware manufacturing. China Merchants Securities pointed out that the commercialization of CoWoP technology is accelerating, and mSAP capacity, equipment, and technical capability will become the next higher-threshold competitive track for PCB manufacturers.

Downstream leading manufacturers have already laid out mSAP capacity. Zhen Ding Technology plans 11 lines and 660,000 square meters. Shennan Circuits plans 7 lines and 420,000 square meters. Jingwang Electronics plans 5 lines and 300,000 square meters. Xingsen Technology plans to add an annual output of 120,000 square meters of mSAP substrate capacity through its Zhuhai project. Dingying Investment Control’s Thailand P5a plant will introduce mSAP process, targeting high-end applications such as AI servers, GPUs, ASICs, and optical modules.

Morgan Stanley estimates that from 2025 to 2028, the global mSAP substrate market for AI optical modules will grow from 620 million US dollars to 3.77 billion US dollars, with a compound annual growth rate of 83 percent. mSAP is undergoing a penetration trajectory similar to HDI ten years ago, starting from high-end applications and gradually becoming mainstream standard.

Chiplet Architecture Continues to Drive FC-BGA Substrate Demand

Parallel to the mSAP process upgrade is the continuous pull of the Chiplet architecture on FC-BGA substrate demand.

Traditional monolithic chip design is facing physical limits in area, yield, and cost. Chiplet splits a large chip into multiple small chiplets and integrates them on a shared substrate through advanced packaging. This architecture places requirements on packaging substrate I/O density, signal integrity, and heat dissipation efficiency far beyond traditional solutions. Traditional 4 to 6 layer BT substrates can no longer meet demand. ABF substrates are accelerating toward ultra-high-end specifications of more than 10 layers, line width and spacing below 10 micrometers, and size exceeding 100 mm by 100 mm.

Advanced packaging is upgrading from a traditional back-end supporting role to a core fulcrum for extending Moore’s Law. As the core substrate accounting for more than 50 percent of the cost in advanced packaging, IC substrates are upgrading from packaging supporting role to key computing power carrier. FC-BGA substrates, widely used in CPUs, GPUs, AI accelerators, and high-performance network processors, are expected to account for more than 58.9 percent of the advanced packaging substrate market in 2026.

Data on both supply and demand sides intuitively reflect the intensity of this trend. On the demand side, the requirements of AI large models for computing power chip I/O density continue to rise, and FC-BGA packaging substrates and Chiplet interconnection processes are advancing toward ultra-fine circuits. On the supply side, Morgan Stanley predicts that the high-end ABF substrate gap will reach 10 percent in the second half of 2026, expand to 21 percent in 2027, and soar to 42 percent in 2028. Goldman Sachs’ qualitative judgment is more direct: this round of substrate supply tightness is more lasting than memory chips. The monthly capacity gap for ABF substrates reaches 15 to 20 percent. Substrate delivery times are generally extended to 24 to 36 weeks, and unit prices have increased by more than 35 percent year-on-year.

Global leading substrate manufacturers have taken comprehensive action. LG Innotek’s FC-BGA production line is already operating near full capacity. Samsung Electro-Mechanics plans to invest 1.2 billion US dollars in its Vietnam plant to expand FC-BGA capacity. Shennan Circuits’ Guangzhou ABF production line is steadily ramping up. Products of 22 layers and below have been mass-produced, and high-order products of 24 layers and above continue to be sent for sample verification.

Dual Resonance of Process and Packaging

The mSAP process upgrade and Chiplet packaging evolution together constitute the two core driving forces of the high-end PCB industry in 2026. mSAP provides the manufacturing-level entry capability for high-order PCB. Without an mSAP production line, it is impossible to undertake high-end orders such as 1.6T optical modules and CoWoP motherboards. FC-BGA substrates provide the packaging-level carrying base for the Chiplet architecture. Without sufficient high-end substrate capacity, the Chiplet solution cannot be implemented on a large scale.

The two form a close linkage in the industry chain. The FC-BGA substrate demand driven by Chiplet further increases the importance of mSAP process in substrate manufacturing. The expansion of mSAP capacity provides process assurance for the refined production of FC-BGA substrates. In this round of industrial upgrading driven by AI computing power, enterprises that master mSAP process capabilities and FC-BGA substrate capacity are standing at the forefront of industry chain value distribution.

Gopcba provides professional PCB manufacturing, PCB assembly, prototype PCB assembly, low-volume PCB assembly, high-volume PCB assembly, SMT PCB assembly, through-hole PCB assembly, mixed-technology PCB assembly, flex PCB assembly, PCB design layout, components procurement, rapid PCBA prototyping, conformal coating, PCBA testing, box build assembly, wire cable harness assembly, medical PCBA, telecommunications PCBA, energy PCBA, industrial PCBA, artificial intelligence PCBA, Internet of Things PCBA, PCB capabilities, and PCBA capabilities. You can also visit our blog, learn about us, see why us, review our quality management, or contact us for more information.