The manufacturing of PCB and IC substrates is categorized into three primary processes based on how copper layers are added or removed: subtractive, semi-additive, and fully additive methods.

Subtractive Processing

This method uses photolithography to create a resist pattern, followed by etching to remove unwanted copper foil. After stripping the resist, the conductive circuit is formed. It is a mature, low-cost process suitable for large-scale production, but suffers from undercutting, limiting line width and spacing to a practical minimum of about 50 microns, which prevents ultra-fine circuit creation. It is primarily used for mid-to-low-end general PCBs, including single and double-sided boards, standard multi-layer boards, and boards for industrial and consumer electronics.

Semi-Additive Processing (SAP)

This process begins with electroless copper plating to create a thin seed layer. A photoresist pattern is then applied, and the circuit areas are thickened through electroplating. Finally, the photoresist is removed, and a flash etching step eliminates the ultrathin seed layer from non-circuit areas. This avoids undercutting issues, achieving line widths and spacing of 10 to 20 microns. However, the process is more complex and requires significant capital investment for equipment like electroless plating and electroplating systems. It is used for high-end HDI boards, IC substrates, and substrate-like PCBs (SLP) for smartphones.

Fully Additive Processing (AAP)

This method uses a specialized insulating substrate where a catalyst is activated in circuit areas through photolithography. Circuits are then formed solely by electroless copper plating, with no etching step involved. It offers the highest precision with no undercutting, theoretically achieving line widths below 5 microns. However, the process is extremely difficult and differs significantly from mainstream PCB manufacturing, resulting in poor scalability. Its application is limited to small-scale production of ultra-high-end IC substrates, such as FCBGA substrates and fan-out packaging substrates.

Overview of the MSAP Process (Modified Semi-Additive Processing)

The MSAP process is an optimized version of traditional SAP, designed to improve scalability, cost-effectiveness, and large-format compatibility. Its core innovation involves using a 2-3 micron carrier copper foil (a peelable ultra-thin copper foil on a carrier) instead of an electroless copper seed layer. It also optimizes the parameters for electroplating and flash etching. This method fills the technological gap between subtractive and SAP processes, achieving an optimal balance of precision, yield, and cost for the 20-40 micron line width range. It is the core mass-production process for the substrate-level upgrade of PCBs. Current applications include IC substrates, SLP, high-end HDI, and PCBs for 1.6T optical modules. The primary growth drivers are AI servers and high-speed optical modules.

Key Value-Add Segments

MSAP Mass Production Manufacturers

Taiwanese manufacturers lead in technology and yield, holding the majority of the global market share, but their expansion pace is conservative. Key players include Zhen Ding Technology, Unimicron Technology, Nanya PCB, and Kinsus Interconnect Technology.

Mainland Chinese manufacturers are the primary source of global capacity growth, with leading PCB and substrate companies achieving stable mass production. These include Pegatron, Shennan Circuits, WUS Printed Circuit, Kinwong Electronic, Fastprint Circuit Tech, and Founder Technology.

Material/Equipment Manufacturers

Carrier copper foil replaces the traditional electroless copper seed layer. This market has been long dominated by Mitsui Mining & Smelting of Japan, but is currently in the initial, 0-to-1 stage of domestic substitution in China. Players include Fangbang Electronics, Tongguan Copper Foil, and Defu Technology.

Wet electronic chemicals for MSAP require far higher control over electroplating uniformity and flash etching undercut than traditional processes, significantly increasing the value of the chemical solutions. Manufacturers include Tiancheng Technology, Guanghua Technology, and Sanfu New Materials.

Equipment for the MSAP process demands higher precision, substantially increasing the value of LDI exposure, drilling, and electroplating equipment. Key manufacturers include Cheng Mei Materials, Han's Laser Technology, Dongwei Technology, and Tai Jin New Energy.