Although the PCB often plays a supporting rather than a starring role, it serves as the primary foundation for installing and interconnecting electronic components, making it an essential component in all electronic products. From mobile phones and PDAs to personal computers, PCBs are virtually indispensable.
Take Taiwan as an example: as early as 2004, the output value of Taiwan’s PCB-related applied materials industry reached 45.27 billion Taiwan dollars, accounting for 35.8% of the total output value of Taiwan’s electronic materials industry and ranking first among its six major sectors. That year, Taiwan led the world in the output of electronic glass fiber cloth, flexible copper-clad laminate, and IC carrier plates (PCBs).
Since last year, due to sharp increases in international copper prices and growing product applications, upstream raw materials like copper foil substrates have seen price hikes and increased shipments. In 2006, Taiwan’s market for printed circuit board materials reached NT $77.7 billion, up nearly 21% from 2005.
In 2007, steady increases in raw material prices such as copper foil and glass fiber yarn/cloth led substrate manufacturers to mitigate sharp price hikes, enhancing their price competitiveness. Despite the traditional first-quarter slump, PCB output in Q1 of 2007 rose by 7% compared to the previous year, driven by robust demand for consumer goods. Growth in soft PCBs was modest at around 1%, influenced by slower growth in mobile products and declining LCD soft board prices, while IC carrier board growth hovered around 2% due to oversupply.
In recent years, heightened environmental consciousness has spurred a trend toward eco-friendly raw materials. For instance, Japan’s JPCA Exhibition showcases numerous environmental resource recovery technologies. Furthermore, major PCB manufacturers are focusing on advancing technologies for high frequency, heat resistance, and overall performance. Meanwhile, consumer electronics are pushing for thinner profiles, a trend that extends to PCB materials themselves.
In the manufacture of rigid PCBs, materials have remained largely unchanged, typically comprising copper foil substrates (CCL), copper foil, films, and various chemicals. Copper foil substrates, which primarily consist of glass fiber cloth and electrolytic copper foil, represent the highest material cost, ranging from 50% to 70% depending on the layer count. Glass fiber cloth reinforces substrate hardness through woven glass fiber yarn.
Having developed over 30 years, Taiwan’s PCB industry boasts a comprehensive upstream, midstream, and downstream structure. Taiwanese manufacturers have achieved global leadership in glass fiber yarn and cloth production. Electrolytic copper foil, a crucial electronic material, demands high standards, including heat and oxidation resistance, surface integrity free of pinholes and wrinkles, high peel strength with laminates, and compatibility with standard etching methods to avoid substrate contamination like particle migration.
The classification of copper foil substrates, critical in PCB production, varies by raw materials and flame retardancy. Based on reinforcement materials, substrates are categorized into paper-based, glass fiber cloth-based, composite (CEM series), multilayer board, and special materials (ceramics, metal core). Resin adhesives used in the base plate include phenolic resin (XPc, XxxPC, FR-1, FR-2), epoxy resin (FR-3), polyester resin, among others. Epoxy resin (FR-4, FR-5) dominates glass fiber cloth-based substrates, supplemented by special resins such as Gemalais and imine-modified triamcinolone resin (BT).
As electronic product functionalities become more complex with higher frequency and performance demands, PCBs are increasingly shifting toward multilayer boards. Consequently, glass fiber cloth-based copper foil substrates currently dominate the market.
According to fire resistance characteristics, PCBs can be divided into two main categories: flame retardant (UL94-VO, UL94-V1) and non-flame retardant (UL94-HB) substrates. In recent years, increased environmental awareness has highlighted a new category of bromine-free CCLs within flame retardant PCBs, termed “green flame retardant CCLs”. With advancing electronic product technology, there is a growing demand for higher performance PCBs. Accordingly, PCBs are classified based on performance into general-purpose, low dielectric constant, high heat resistance (with Tg above 150°C), low thermal expansion coefficient (commonly used in packaging substrates), and other types.
Since the 1960s and 1970s, flexible printed circuit boards (FPCs) have been widely adopted in automotive and photographic industries. Initially serving as cable and wire substitutes, FPCs were limited by technology. By the 1980s, their application scope expanded into telecommunications and military sectors, increasingly incorporating automated processes. In the 1990s, driven by the information age, FPCs found new roles in portable devices like mobile phones and laptops, emphasizing functionality, compact size, and lightweight construction. Additionally, LCD panel COF technology and IC structure loading boards have become primary applications for flexible PCBs.
A flexible printed circuit board (FPC) comprises an insulating substrate, adhesive, and copper conductors, earning its name from its flexibility. Notably, FPCs enable three-dimensional wiring, allowing for embedded conductors shaped freely with equipment. They offer flexibility, lightness, and thinness unattainable by traditional rigid laminated boards. FPCs are typically classified as single-sided, double-sided, multi-layered, and hybrids of soft and hard materials.
Single-sided FPCs, due to their single conductor layer, may optionally include a cover layer. Insulating substrates vary by application, commonly employing materials like polyester, polyimide, polytetrafluoroethylene, and soft epoxy glass fiber cloth. Double-sided FPCs incorporate two conductor layers, while multi-layer FPCs employ lamination technology to achieve structures with three or more layers. Hybrid PCBs integrate both soft and hard PCB elements, reducing weight and volume while enhancing reliability, assembly density, and electrical characteristics.
To further miniaturize portable electronics, there’s a growing trend towards high-density PCB wiring and the adoption of three-dimensional, multi-axis installations using flexible substrates (FPCs). This shift from 2D planar components to 3D installations helps reduce product component and substrate space. Recently, the combination of 3D-mounted FPCs and multilayer rigid PCBs has gained widespread use as hardboard flexible substrate technology.
The transition to lead-free processes, driven by environmental and regulatory pressures like EU RoHS specifications, has significantly impacted PCB manufacturing. Higher lead-free soldering temperatures have increased failure risks such as delamination, lamination fractures, Cu cracks, and CAF (conductive anode wire whisker) failures, particularly in large, complex thick circuit boards. Surface coating materials also play a crucial role.
In practical applications, joints between soldering and Ni layers (from ENIG coating) are more susceptible to failure compared to joints with Cu (e.g., OSP and silver immersion), leading to comprehensive failure scenarios akin to those seen with Microsoft Xbox 360. Design considerations are critical to mitigate such issues, especially under mechanical stresses like drop tests, which can exacerbate PCB cracking associated with lead-free soldering. The PCB industry must innovate in material design concepts to meet the challenges posed by this green process trend.
In the past year, rising copper prices exerted significant cost pressures on PCB-related industries, though this has somewhat eased. However, escalating crude oil prices this year have renewed cost pressures on PCB materials, surpassing the capacity of PCB manufacturers to absorb. Taiwan’s access to critical materials is often constrained by foreign suppliers, impacting its competitiveness amid competition from countries like mainland China, Japan, and South Korea, prompting concerns among Taiwanese PCB manufacturers.
Take Taiwan as an example: as early as 2004, the output value of Taiwan’s PCB-related applied materials industry reached 45.27 billion Taiwan dollars, accounting for 35.8% of the total output value of Taiwan’s electronic materials industry and ranking first among its six major sectors. That year, Taiwan led the world in the output of electronic glass fiber cloth, flexible copper-clad laminate, and IC carrier plates (PCBs).
Since last year, due to sharp increases in international copper prices and growing product applications, upstream raw materials like copper foil substrates have seen price hikes and increased shipments. In 2006, Taiwan’s market for printed circuit board materials reached NT $77.7 billion, up nearly 21% from 2005.
In 2007, steady increases in raw material prices such as copper foil and glass fiber yarn/cloth led substrate manufacturers to mitigate sharp price hikes, enhancing their price competitiveness. Despite the traditional first-quarter slump, PCB output in Q1 of 2007 rose by 7% compared to the previous year, driven by robust demand for consumer goods. Growth in soft PCBs was modest at around 1%, influenced by slower growth in mobile products and declining LCD soft board prices, while IC carrier board growth hovered around 2% due to oversupply.
In recent years, heightened environmental consciousness has spurred a trend toward eco-friendly raw materials. For instance, Japan’s JPCA Exhibition showcases numerous environmental resource recovery technologies. Furthermore, major PCB manufacturers are focusing on advancing technologies for high frequency, heat resistance, and overall performance. Meanwhile, consumer electronics are pushing for thinner profiles, a trend that extends to PCB materials themselves.
In the manufacture of rigid PCBs, materials have remained largely unchanged, typically comprising copper foil substrates (CCL), copper foil, films, and various chemicals. Copper foil substrates, which primarily consist of glass fiber cloth and electrolytic copper foil, represent the highest material cost, ranging from 50% to 70% depending on the layer count. Glass fiber cloth reinforces substrate hardness through woven glass fiber yarn.
Having developed over 30 years, Taiwan’s PCB industry boasts a comprehensive upstream, midstream, and downstream structure. Taiwanese manufacturers have achieved global leadership in glass fiber yarn and cloth production. Electrolytic copper foil, a crucial electronic material, demands high standards, including heat and oxidation resistance, surface integrity free of pinholes and wrinkles, high peel strength with laminates, and compatibility with standard etching methods to avoid substrate contamination like particle migration.
The classification of copper foil substrates, critical in PCB production, varies by raw materials and flame retardancy. Based on reinforcement materials, substrates are categorized into paper-based, glass fiber cloth-based, composite (CEM series), multilayer board, and special materials (ceramics, metal core). Resin adhesives used in the base plate include phenolic resin (XPc, XxxPC, FR-1, FR-2), epoxy resin (FR-3), polyester resin, among others. Epoxy resin (FR-4, FR-5) dominates glass fiber cloth-based substrates, supplemented by special resins such as Gemalais and imine-modified triamcinolone resin (BT).
As electronic product functionalities become more complex with higher frequency and performance demands, PCBs are increasingly shifting toward multilayer boards. Consequently, glass fiber cloth-based copper foil substrates currently dominate the market.
According to fire resistance characteristics, PCBs can be divided into two main categories: flame retardant (UL94-VO, UL94-V1) and non-flame retardant (UL94-HB) substrates. In recent years, increased environmental awareness has highlighted a new category of bromine-free CCLs within flame retardant PCBs, termed “green flame retardant CCLs”. With advancing electronic product technology, there is a growing demand for higher performance PCBs. Accordingly, PCBs are classified based on performance into general-purpose, low dielectric constant, high heat resistance (with Tg above 150°C), low thermal expansion coefficient (commonly used in packaging substrates), and other types.
Since the 1960s and 1970s, flexible printed circuit boards (FPCs) have been widely adopted in automotive and photographic industries. Initially serving as cable and wire substitutes, FPCs were limited by technology. By the 1980s, their application scope expanded into telecommunications and military sectors, increasingly incorporating automated processes. In the 1990s, driven by the information age, FPCs found new roles in portable devices like mobile phones and laptops, emphasizing functionality, compact size, and lightweight construction. Additionally, LCD panel COF technology and IC structure loading boards have become primary applications for flexible PCBs.
A flexible printed circuit board (FPC) comprises an insulating substrate, adhesive, and copper conductors, earning its name from its flexibility. Notably, FPCs enable three-dimensional wiring, allowing for embedded conductors shaped freely with equipment. They offer flexibility, lightness, and thinness unattainable by traditional rigid laminated boards. FPCs are typically classified as single-sided, double-sided, multi-layered, and hybrids of soft and hard materials.
Single-sided FPCs, due to their single conductor layer, may optionally include a cover layer. Insulating substrates vary by application, commonly employing materials like polyester, polyimide, polytetrafluoroethylene, and soft epoxy glass fiber cloth. Double-sided FPCs incorporate two conductor layers, while multi-layer FPCs employ lamination technology to achieve structures with three or more layers. Hybrid PCBs integrate both soft and hard PCB elements, reducing weight and volume while enhancing reliability, assembly density, and electrical characteristics.
To further miniaturize portable electronics, there’s a growing trend towards high-density PCB wiring and the adoption of three-dimensional, multi-axis installations using flexible substrates (FPCs). This shift from 2D planar components to 3D installations helps reduce product component and substrate space. Recently, the combination of 3D-mounted FPCs and multilayer rigid PCBs has gained widespread use as hardboard flexible substrate technology.
The transition to lead-free processes, driven by environmental and regulatory pressures like EU RoHS specifications, has significantly impacted PCB manufacturing. Higher lead-free soldering temperatures have increased failure risks such as delamination, lamination fractures, Cu cracks, and CAF (conductive anode wire whisker) failures, particularly in large, complex thick circuit boards. Surface coating materials also play a crucial role.
In practical applications, joints between soldering and Ni layers (from ENIG coating) are more susceptible to failure compared to joints with Cu (e.g., OSP and silver immersion), leading to comprehensive failure scenarios akin to those seen with Microsoft Xbox 360. Design considerations are critical to mitigate such issues, especially under mechanical stresses like drop tests, which can exacerbate PCB cracking associated with lead-free soldering. The PCB industry must innovate in material design concepts to meet the challenges posed by this green process trend.
In the past year, rising copper prices exerted significant cost pressures on PCB-related industries, though this has somewhat eased. However, escalating crude oil prices this year have renewed cost pressures on PCB materials, surpassing the capacity of PCB manufacturers to absorb. Taiwan’s access to critical materials is often constrained by foreign suppliers, impacting its competitiveness amid competition from countries like mainland China, Japan, and South Korea, prompting concerns among Taiwanese PCB manufacturers.
