Manufacturing Better Electronics With PCB Laminates

At the heart of those electronics are PCBs, or Printed Circuit Boards, which prevent the conduction of signals or current via conductive pathways etched and laminated with multiple sheets.

 

Image used courtesy of Adobe Stock

 

PCBs are used in limitless industries (consumer electronics, automotive, aviation, medical, etc.) to which they deliver stability and performance. The major role is played by the laminates used while manufacturing PCBs, as PCB laminates are what binds and holds the component layers together.

 

Mobile, 5G to Boost PCB Laminate Demand

The soaring demand in the communication industry, due to the advancements and improvements in data transmission, makes it the largest application of PCBs and PCB laminates.

According to Information and Communication Technology (ICT) provider Ericsson, the number of mobile subscriptions is projected to increase from 8.2 billion by the end of 2021 to more than 9 billion by 2027.

 

Figure 1. Global Mobile Subscriptions 2022-2027. Image used courtesy of Stratview Research

 

The global count of 5G subscribers is also growing rapidly. Estimates suggest that 5G will become the prevailing mobile access technology by subscriptions in the year 2027, with more than 4.4 billion subscriptions globally, accounting for 48% of all mobile subscriptions.

 

Figure 2. PCB Production by volume (APAC, 2020). Image used courtesy of Stratview Research

 

To meet such growing demand, mobile manufacturers have been focusing on accelerating production, which increases the demand for PCB laminates. The majority of mobile subscribers come from Asia-Pacific (Figure 3), and Asia-Pacific accounted for more than 85% of PCB production in 2020 (Figure 2 depicts the share of production of PCBs in the APAC region). APAC boasts the largest PCB production base globally. 

 

Figure 4. Mobile Subscriptions by Region (2021-2025). Image used courtesy of Stratview Research

 

Do All Industries Use the Same Type of PCBs?

PCBs across different industries are not created equal. The terms single-sided, double-sided, and multilayer or rigid, flexible, and high-density interconnect/HDI are often used to describe PCBs. Manufacturers use these terms to categorize the complexity of a board’s structure.

 

Manufacturing printed circuit boards. Image used courtesy of Adobe Stock

 

Single-sided: Ideal for simple low-density designs, these boards are used usually in radios, coffee makers, camera systems, and other consumer electronics.

Double-sided: There are limitless applications of double-sided PCBs. Examples include industrial controls, UPS systems, and regulators.

Multilayer: Having higher assembly density, and increased flexibility, these multilayer PCBs are used more than any other type. Examples of applications of multilayer PCBs are computers, mobile devices, medical devices like heart monitors, and X-ray equipment.

Rigid: A rigid PCB board is made of ceramic or glass. Durable enough to withstand high heat and prolonged exposure to the elements, this is used in devices like printers.

Flexible: A flexible printed circuit is a form of conductor printed onto a flexible insulating film and can be used in military and space applications.

PCB manufacturers have seen increased demand for rigid-multilayer boards, a combination of multilayer and rigid PCBs, due to the need for smaller, complex devices. These combination multilayer-rigid boards, by their innate versatile properties, provide multiple benefits such as:

• High capacity and high speed in a smaller footprint
• Reduced need for connectors required for multiple layers of PCBs
• Simplified construction
• Lighter weight

 

What Are PCBs Made of? 

These flat laminated composites can be made of either one or two layers of copper. In high-density applications, they can have as many as 40 or 50 layers or even more. Manufacturers look for the following characteristics for the laminates used in PCBs:

• Dielectric constant
• Fire retardance
• Tensile strength
• Glass transition temperature
• Shear strength

 

Table 1. Types of Laminates and Their Characteristics.

Laminates	Characteristics	Materials used
FR – 4	Flame-resistant material, good thermal, electrical, and mechanical characteristics, a favorable strength-to-weight ratio makes it ideal for most devices.	Woven fiberglass cloth and epoxy resin binder.
High Tg (glass transition temperature)	Superior thermal performance and chemical resistance. Offers excellent electrical insulation in devices with extreme humidity and temperatures.	Copper-coated laminate treated by internal layer imaging along with PREPREG layers application.
CEM (Composite Epoxy Material)	Comes in 5 variants. CEM-1 is a low-cost, cellulose-paper-based laminate with just one layer of woven glass fabric. CEM-2 has cellulose paper core and woven glass fabric surfaces. CEM-3 (similar to FR-4) is white in color and is flame-retardant. CEM-4 (similar to CEM-3) is not flame-retardant. CEM-5 (also called CRM-5) has a polyester woven glass core.	Layers of woven glass fabric and paper (cellulose) along with epoxy (source -pcbdirectory)
Halogen Free FR-4	Phosphorus or nitrogen materials are used to replace halogens as frame-retardants, they have smaller thermal expansion coefficient, and moisture-absorption rate.	Halogen-free copper-clad (phosphorus and phosphorus-nitrogen)

 

The favorable characteristics and properties of ‘FR4’ support its widespread usage. FR4 laminates are made from fiberglass cloth and epoxy resin. These are usually the lowest cost laminates available for PCBs.

 

Characteristics of FR4 PCB Laminates

The characteristics of FR4 PCB laminates include:

• Flame retardance: FR4 laminates are flame-retardant systems of woven glass covered with epoxy-like resin. These laminates gain their fire-retardancy from the presence of the halogen chemical element bromine. 
• Good electrical properties: The electrical properties of FR4 PCB laminates are critical for signal integrity. They specify how fast an electrical signal propagates through the material and how much electric charge it can retain. 
• Low moisture absorption: This property makes FR4 PCB laminate material highly resistant to water and delamination. FR4 materials offer a low moisture absorption of 0.1% even when immersed in water for 24 hours.
• Cost-effectiveness: These materials are lower cost when compared to other materials.

 

Trends Powering the PCB Market

Efforts to eliminate environmentally unfriendly substances are already impacting the PCB laminates market. This trend opens the doors for ‘halogen-free’ laminates. The use of halogen as a flame-retardant, which emits a large amount of highly toxic gas, is being replaced by phosphorus and phosphorus-nitrogen.

These ‘halogen-free’ laminates provide good stability, improved insulation, and water absorption properties, making them more expensive than conventional PCBs.

The shift toward miniaturization is increasing HDI techniques, which means fewer layers on board yet provides amazing signal transmission speed.

Tech-friendly PCB laminates could be the next big thing in the PCB market. The Internet of Things (IoT) is being widely applied in manufacturing smart home appliances, smart wearable devices, and automotive LCD displays. 

According to the latest statistics on IoT devices, the number of IoT-connected devices will exceed 3.5 billion by 2023. By 2025, more than 152,000 IoT devices will connect to the internet every minute.

PCB laminates have transformed over the years. After COVID-19 hit, a deficit in copper supplies, the prime element needed for manufacturing PCBs, led to an increase in raw materials prices. Although, due to the high demand for electronic devices, the market is slowly and steadily growing. 

A gradual shift toward such trends is likely to create new revenue streams for market players and by 2027, the PCB laminates market could reach $20.5 billion, according to Stratview Research.

 

Future Consumer Electronics Landscape

There are a few instances that could change the present prospect of the PCB laminates market. Government programs encourage tech giants to shift their production units to India and other countries. Similarly, rising geopolitical tensions, like the US-China trade war and supply chain crunches amid the pandemic are forcing several giants like Google and Apple to move production to nearby countries.

 

Automated robotic assembly of an electronic circuit board. Image used courtesy of Adobe Stock

 

For example, Apple has diversified its supply chains from China and started manufacturing iPhone 14 in India and iPads and watches in Vietnam as tensions rise between Washington and Beijing. Rising labor costs in South Korea and China have pushed Samsung to discontinue its mobile production in these regions and shift to countries like India and Vietnam.

Irrespective of the other developments in the industry, the changing manufacturing landscape for electronics is worth noticing. With growing consumer demands for smarter and smaller products, industries are now focused on accelerating production.

The future of the PCB industry, thus, is luminous, shaped by product performance and miniaturization to make consumers’ lives easier.