Printed Circuit Boards (PCBs) are indispensable components in modern electronic devices, often referred to as the "Mother of the Electronics Industry." What exactly are PCBs? How are the supply chain of the PCB industry connected and what are the primary end-use applications? In this article, we will walk through the PCB industry in detail.

What is PCB?

A Printed Circuit Board (PCB) consists of a substrate layered with copper foil and insulation materials. The copper foil is etched and printed to form circuits, allowing the PCB to perform functions such as electrical connectivity and signal transmission. PCBs are vital to nearly all electronic products, earning them the title of the "Mother of the Electronics Industry."

The PCB Industry Supply Chain

Upstream: Raw Materials

The upstream segment primarily provides materials for substrates, including fiberglass, copper foil, and resin.

• Fiberglass and resin: Supplied by companies such as Fulltech Fiber Glass (1815), Taiwan Glass (1802), and Taimide (3645).
• Copper foil: Accounting for approximately 27% of PCB board costs, copper foil is a key material supplied by Co-Tech (8358), Nan Ya (1303), and Chang Chun Chemical.

Midstream: Manufacturing and Assembly

PCBs are classified into rigid boards, flexible boards, and IC substrates, catering to different use cases.

1. Rigid Boards

Rigid boards are manufactured from durable materials such as fiberglass or phenolic boards. Their non-flexible and highly stable characteristics make them particularly suitable for larger devices such as televisions and computers. Rigid boards are typically categorized into several types: single-layer boards, double-layer boards, multilayer boards, and high-density interconnect (HDI) boards. Among these, HDI boards, known for their high density and compact size, have emerged as the leading trend in rigid board technology. Key players in this industry include Compeq Manufacturing (2313), Tripod Technology (3044), and Gold Circuit (2368).

2. Flexible Boards

Lightweight and bendable, flexible boards are well-suited for compact electronics such as smartphones and cameras. Based on the materials used, flexible boards can be categorized into PI, MPI, and LCP. While PI is gradually being phased out, MPI and LCP are primarily used for medium- and high-frequency products, respectively. Due to the smaller market demand, only a limited number of manufacturers specialize in flexible boards. Key players include Zhen Ding (4958), Flexium Interconnect (6269), and Compeq Manufacturing (2313).

3. IC Substrates

IC Substrates serve as carriers for IC chips,

• Serve as carriers for IC chips, providing protection, signal connectivity, and heat dissipation.
• Types: ABF, BT, and EMC substrates.
  • ABF substrates: Used for GPUs, CPUs, and ASICs, benefitting from advancements in AI and packaging technologies.
  • BT substrates: Commonly found in memory and mobile applications.
    • Key players: The "Big Three" in Taiwan—Unimicron (3037), Kinsus (3189), and Nan Ya PCB (8046).

Downstream: End Applications

Since almost all electronic devices require circuit connections, PCB applications are omnipresent, spanning automotive, medical, industrial, and consumer electronics.

Recent advancements in AI have driven growth in server, GPU, and ASIC markets, increasing demand for PCBs with higher layer counts, denser circuits, and smaller form factors.