The development of printed circuit boards, or PCBs, has a rich history dating back to the early 20th century. PCBs were originally created as a solution to the complex wiring systems found in early electronics, and over time have become a critical component in the manufacturing of electronic devices. Let’s see how printed circuit board(PCB) developed!
Early PCB manufacturing process
A printed circuit board was born in Japan in 1936. But the work that really gave it significance was done by Dr. Eisler in England. In 1940, with the help of mature processes such as photography, plate making, and corrosion in printing technology, he manufactured the first printed circuit board with practical value on an insulating substrate covered with metal foil.
In 1947, the United States held the first printed circuit technology seminar, which summarized the main manufacturing methods of printed circuits before, and summarized them into six categories: coating method, spraying method, molding method, powder pressing method, vacuum coating method and chemical deposition method.
However, these methods have not been able to achieve large-scale industrial production, and some of them are still used for reference and extended. For example, ceramic substrates suitable for coating method to manufacture hybrid circuits have been retained as an important technology, and circuit boards formed by printing conductive paste on insulating substrates have gradually attracted attention and will be promoted to industrialization in the future. In addition, the chemical deposition method is the basis of the additive method to manufacture printed circuit boards, and it is still under research and development.
Development of modern printed circuits
The concept of the “Printed Circuit” was first proposed by Dr. Eisler of the United Kingdom in 1936, but it did not arouse the interest of electronics manufacturers at that time. Dr. Eisler was dissatisfied with the research and comparison of the original process methods, so he proposed the copper foil etching process. It was he who pioneered the current mainstream printed circuit large-scale manufacturing method, that is, after coating the insulating substrate fully covered with metal foil with etching-resistant ink, then corroding the unnecessary metal foil to form a printed circuit board.
In 1942, he used a paper laminated insulating substrate to bond copper foil, screen-printed conductive patterns, and then etched away the unnecessary copper foil to produce a printed circuit board for radio. This craft was neglected in the UK at the time, but it was first accepted by the Americans. In World War II, Americans applied the technology invented by Dr. Eisler to manufacture printed circuit boards, which were used in military electronic devices and achieved great success, which attracted the attention of electronics manufacturers.
By the early 1950s, the copper foil etching method became the most practical printed circuit board manufacturing technology and began to be widely used. Therefore, Dr. Eisler is also known as “the father of printed circuits”.
Since the copper foil etching method became the main method of printed circuit production, printed circuit technology has developed very rapidly, and it has better adapted to the needs of the rapid development of electronic technology. In fact, the development of printed circuits is carried out almost simultaneously with the development of semiconductor devices.
Let’s see how printed circuit board (PCB) technology developed during 70 years from the 1950s to the 2020s.
(1) 1950s
Around the 1950s, when the transistor came out, a single-layer PCB could meet the application requirements of a transistor radio. Products are mainly civilian appliances, such as radios, televisions and so on.
The manufacturing method of single-layer PCB is to use copper-clad paper-based phenolic resin laminate (PP board) as the base material, and use chemicals to dissolve the unnecessary copper foil on the PP board, and the remaining copper lines are all designed circuits. This production technique is called the “subtractive process”.
However, even in some branded electronics manufacturers at that time, the PCB subtractive process was still dominated by manual operations, and the corrosive solution used was ferric chloride. At that time, the representative application product of printed circuit boards was Sony’s portable transistor radio, which was a single-sided PCB using PP substrate. In 1958, Japan published the earliest enlightenment book in the printed circuit industry, namely “Printed Circuits”.
In the late 1950s, electronic tubes were gradually replaced by transistors, and the electronics industry entered the “transistor era”. In order to meet the needs of production development, the printed circuit board has developed from a single-sided phenolic resin base to an epoxy resin-based insulating layer material reinforced with glass fiber cloth.
(2) 1960s
In 1955, Oki Electric Company of Japan entered into technical cooperation with Raytheon Company of the United States to manufacture marine radar. Raytheon Company specifies that the PCB should be applied with copper-clad glass cloth epoxy resin laminate (GE substrate). The GE base material developed in Japan has realized the mass production of marine radar.
Since 1960, OKI Electric Co., Ltd. began to use a large number of GE substrate materials on the PCB of mass-produced electrical transmission devices. In 1962, the Japan Printed Circuit Industry Association was established. In 1964, the American Optical Circuit Company developed a thick copper electroless copper plating solution (CC-4 solution), and started a new additive process for manufacturing printed circuit boards. Hitachi Chemical Company introduced CC-4 technology for GE substrate of PCB. In the initial application, GE substrates had problems such as heating warpage and copper foil peeling, which were significantly improved after gradual improvements by material manufacturers. Since 1965, several material manufacturers in Japan have begun to mass-produce GE substrates.
Around 1960, “double-layer PCB” and “hole metallized double-sided printed circuit boards” with circuit patterns on both sides were put into production one after another. At the same time, “multi-layer printed circuit boards” that overlapped several layers of printed circuit boards were also developed. At this time, the products were mainly used in precision electronic instruments and military electronic equipment.
Around 1968, medium and large-scale integrated circuits had been developed and put into production. The “hole metallized double-sided PCB” that is compatible with it has gradually replaced the single-sided PCB, and a soft, foldable and bendable “flexible PCB” has also been developed.
(3) 1970s
After 1970, the emergence of large-scale integrated circuits accelerated the development of printed circuits in the direction of multilayering. Electronic computers with small size and many functions have also come out one after another. Communication equipment manufacturers such as Japan’s Oki Electric Co., Ltd. have set up PCB production factories, and PCB professional manufacturing companies have also risen rapidly.
At this time, the use of plated-through holes to realize the interlayer interconnection of PCB is gradually adopted. In the 10 years from 1972 to 1981, the amount of PCB production in Japan increased by about 6 times (the output value in 1972 was 47.1 billion yen, and the output value in 1981 was 302.1 billion yen), which is a leapfrog record.
Since 1970, the number of PCB layers for electronic switches of telecommunications companies has reached 3 layers. Since then, the development of large computers has promoted the development of more layers of PCB. The number of layers of PCB also starts from 4 layers to 6, 8, 10, 20, 40, 50 layers, and even more layers. At the same time, PCB also achieves high density (refinement of lines, miniaturization of holes, thinning of insulating layer), and the width and spacing of lines are reduced from 0.5mm to smaller sizes of 0.35mm, 0.2mm, and 0.1mm. This greatly increases the wiring density per unit area of the PCB.
In addition, the installation method of components on the PCB has begun a revolutionary change, and the original Through-hole Mounting Technology (THT) has gradually developed into a more sophisticated surface mounting technology (SMT). Historically, Through-hole Mounting Technology have relied on manual operations on PCBs. The successful development of automatic component insertion machine has realized the automatic assembly of components. SMT uses an automatic assembly line to realize the placement of electronic components on both sides of the PCB.
(4) 1980s
After 1980, with the development of ultra-large-scale integrated circuits, it was combined with high-density multilayer printed circuits, and supercomputers with hundreds of millions of calculations appeared. In the 10 years from 1982 to 1991, the output value of PCB in Japan increased by about three times (the output value in 1982 was 361.5 billion yen, and in 1991 it was 1,094 billion yen). The output value of MLB was 146.8 billion yen in 1986, which exceeded the output value of single-sided PCB; by 1989, it was 278.4 billion yen, which was close to the output value of double-sided PCB.
After 1980, the high density of PCB increased significantly. A glass-ceramic-based MLB with up to 62 layers formed. MLB densification has effectively driven intense competition in the development of mobile phones and computers. In 1988, IBM Corporation of the United States took the lead in using up to 42 layers of printed circuits in the production of computers. And now, 80-layer high-density printed circuit has also been put into application.
(5) 1990s
After 1991, the Japanese bubble economy burst, and electronic equipment and PCBs were greatly affected. Gradually recovered after 1994, MLB and flexible PCB also began to grow rapidly, while the output of single-sided PCB and double-sided PCB began to decline.
Since 1998, the build-up method MLB has entered the practical period, and the output has increased rapidly. At the same time, it promotes the miniaturization and ultra-high-density installation of integrated circuit (IC) packaging in the era of area array termination ball grid array (BGA) and chip scale packaging (CSP). With the large-scale development of chip components, SMT technology has entered a period of rapid development in this era, which has significantly increased the interconnection density of electronic products.
(6) 2020s
With the development of electronic products in the direction of miniaturization and thinning, especially the emergence of smart products and equipment, the mounting area of printed circuit board surface components is greatly limited. The three-dimensional installation of components or IC devices, that is, the integrated integration of PCB has become the most important technology in the manufacture of printed circuit boards in the 21st century. For now, the embedding of electronic components can reduce the area of printed circuit boards by 40%, which can greatly reduce the size of printed circuit boards and give more area to batteries or other components.
Outlook
Over the past 70 years, the development of PCB has changed greatly. Since the invention of semiconductor transistors in 1947, the form of electronic equipment has undergone great changes. Semiconductors have developed from integrated circuits (IC), large-scale integrated circuits (LSI), and very large-scale integrated circuits (VLSI) to high integration.
More integrated IC package methods such as multi-chip modules (MCM), ball grid arrays (BGA), and chip-scale packaging (CSP) have been developed. The research on printed circuit board technology in the early 21st century will continue to strive for the realization of high density, miniaturization, light weight and high integration of electronic products, and the leading innovative technology “nanotechnology” in the 21st century will also promote printed circuit products and technology development.
Printed Circuit Boards (PCBs) have a fascinating history that reflects the evolution of electronic technology. Their development spans several key milestones that contributed to the modern, highly sophisticated PCBs we use today.
Early Beginnings: The concept of using conductive pathways to connect electronic components dates back to the early 20th century. The first significant step toward modern PCBs came in the 1930s and 1940s. During this period, engineers and inventors began experimenting with ways to simplify the assembly of electronic circuits. One notable early example is the work of Paul Eisler, an Austrian inventor who developed a method for creating circuit boards using a technique known as "etched circuits" around 1943. This method involved applying a thin layer of conductive material onto an insulating board and then etching away the unwanted parts to create the circuit pathways.
World War II Influence: The development of PCBs gained momentum during World War II. The military’s need for reliable and compact electronic circuits for equipment and communication devices pushed forward the adoption of PCBs. The technology was used in radar and other advanced electronics, showcasing its potential and leading to further refinements.
Post-War Advancements: After the war, the electronics industry saw rapid growth and commercialization. In the 1950s and 1960s, the use of PCBs became more widespread as electronics became more accessible to the public. This era saw significant improvements in PCB manufacturing techniques, including the introduction of multi-layer boards and more sophisticated etching processes.
Modern Era: By the 1970s and 1980s, PCBs had become a standard component in electronic devices, driven by advances in materials and manufacturing technologies. The rise of computers and consumer electronics accelerated the demand for increasingly complex and reliable PCBs. Innovations like surface-mount technology (SMT) and high-density interconnects (HDI) continued to evolve the design and functionality of PCBs.
Today: In the 21st century, PCBs are integral to almost every electronic device, from smartphones to medical equipment. The technology has advanced to include flexible and printed circuit boards, which offer greater versatility and miniaturization options.
The history of PCB (Printed Circuit Board) software is a fascinating journey that mirrors the evolution of technology in electronics design and manufacturing.
Early Days of Circuit Design: Before the advent of PCB software, designing circuits was a labor-intensive process done by hand. Engineers and designers would manually draw circuit diagrams and layouts, which were then used to create physical circuit boards. This method was not only time-consuming but also prone to errors, making it clear that a more efficient solution was needed.
The Rise of Computer-Aided Design (CAD): The 1960s and 1970s saw the introduction of computer-aided design (CAD) tools, which marked the beginning of automated PCB design. Early PCB software was relatively rudimentary, offering basic tools for creating and editing circuit layouts. These early systems were often expensive and required specialized knowledge to operate, limiting their use to larger companies and research institutions.
1980s and 1990s: Growth and Innovation: The 1980s brought significant advancements as PCB software became more accessible and sophisticated. During this period, software tools started to include features like auto-routing (which automatically lays out connections) and more advanced design rule checks. Companies like Cadence, Mentor Graphics, and Altium emerged, offering increasingly powerful software solutions that helped streamline the design process. This era also saw the introduction of graphical user interfaces (GUIs), making the software more user-friendly.
Early 2000s: Increased Integration and User Accessibility: By the early 2000s, PCB software had become an essential tool for designers across various industries. The integration of 3D modeling capabilities allowed designers to visualize how components fit together in three dimensions, improving accuracy and reducing errors. Software also began to offer more robust simulation tools, enabling designers to test their circuits before manufacturing. The growing availability of affordable and powerful PCs contributed to the broader adoption of PCB design software.
Recent Developments and Trends: In the last decade, PCB software has continued to evolve with advancements in technology. Cloud-based solutions and collaboration tools have become more common, allowing teams to work together on designs from different locations. The rise of open-source PCB design tools has made it easier for hobbyists and small businesses to access high-quality design software. Additionally, the integration of artificial intelligence and machine learning is beginning to enhance design automation, making it possible to optimize layouts and detect potential issues more effectively.
The Future of PCB Software: Looking ahead, PCB software is likely to continue evolving with trends such as more advanced AI-driven design assistance, improved integration with other engineering tools, and increased support for emerging technologies like flexible and wearable electronics. As electronics become more complex, the software will need to adapt, offering even more powerful tools for design, simulation, and manufacturing.
The invention of PCB (Printed Circuit Board) design is attributed to several key figures and developments over time, but one standout pioneer is Paul Eisler, an Austrian inventor.
Paul Eisler’s Contribution: In the early 1940s, Paul Eisler developed one of the first practical methods for creating PCBs. Eisler’s work involved using a technique where conductive pathways were etched onto a non-conductive board, which allowed for a more efficient and reliable way to assemble electronic circuits. His invention was crucial during World War II, as it enabled more compact and reliable electronics for radar and other military devices.
Early Developments: Before Eisler’s work, circuit designs were manually wired, which was cumbersome and error-prone. The transition to printed circuits marked a significant advancement, streamlining the manufacturing process and improving the performance and durability of electronic devices.
Post-War Advances: After Eisler’s invention, the technology continued to evolve, with further contributions from engineers and researchers. The 1950s and 1960s saw the development of more sophisticated PCB design techniques and the introduction of automated processes. Companies and individuals began refining the technology, adding features like multi-layer boards and automated routing to enhance the design and manufacturing of PCBs.
Broader Impact: The development of PCB design was not solely the work of one individual but rather a series of innovations and improvements made by many in the field of electronics and manufacturing. Paul Eisler's contributions were foundational, but the technology grew through the efforts of various engineers, researchers, and companies who built upon his early work.
The development of a Printed Circuit Board (PCB) involves several key stages, each crucial for ensuring that the final board performs reliably and meets design specifications. Here’s a breakdown of the typical stages in PCB development:
1. Concept and Design: The process starts with defining the requirements of the PCB based on the electronic device it will support. Engineers and designers create a schematic diagram, which is a detailed drawing that represents the electronic circuits and connections. This step involves deciding on the layout, choosing components, and specifying how they will be interconnected.
2. PCB Layout: Once the schematic is complete, the next stage is to translate it into a physical layout. This involves placing the components on the PCB and routing the electrical connections between them. The layout must account for various factors, including the size of the PCB, the placement of components to minimize signal interference, and the need for heat dissipation.
3. Design Verification: Before moving to manufacturing, the design is thoroughly checked for errors or potential issues. This can include running simulations to test how the circuit will perform, checking for design rule violations, and ensuring that the layout meets all specifications. This stage helps catch and correct problems early, saving time and cost in the long run.
4. Prototyping: With the design verified, a prototype PCB is created. This initial board is used to test the design in real-world conditions. Prototyping helps identify any issues with the board’s functionality, performance, or manufacturability. Adjustments are often made based on these tests.
5. Manufacturing Preparation: Once the prototype is approved, the design is finalized for mass production. This stage involves preparing detailed manufacturing files, including Gerber files, which provide the necessary information for the PCB fabrication process. Manufacturers also select materials and processes that meet the required specifications.
6. PCB Fabrication: The fabrication process involves creating the physical PCB. This includes printing the circuit patterns onto the board, etching away excess copper, and adding layers if it's a multi-layer board. The board is then drilled for component mounting and plated with finishes that help with soldering and protect the circuits.
7. Assembly: After fabrication, the PCB goes through the assembly stage, where electronic components are soldered onto the board. This can be done using automated processes like pick-and-place machines and solder reflow ovens, or manually for more complex or small-batch boards. Quality control checks are performed to ensure that all components are correctly placed and soldered.
8. Testing and Quality Assurance: The assembled PCBs are tested to ensure they function as intended. This can involve various tests, such as electrical testing, functional testing, and thermal testing. Any defects or issues found during this stage are addressed before the PCBs are shipped to customers or integrated into products.
9. Final Adjustments and Production: Based on testing results, final adjustments may be made to the design or manufacturing process. Once everything is confirmed to be working correctly, full-scale production can begin. This stage ensures that the PCBs meet all quality and performance standards consistently.
PCBA development, or Printed Circuit Board Assembly development, is the process of transforming a designed PCB (Printed Circuit Board) into a fully functional electronic assembly. This involves several stages that go beyond just designing the board itself. Here’s a breakdown of what PCBA development entails:
1. Design Finalization: The first step in PCBA development is to finalize the PCB design. This includes making sure that the board layout, component placement, and circuit connections are all correct and optimized for performance. Once the design is complete, it’s converted into manufacturing files that provide detailed instructions for creating the board and assembling the components.
2. Prototyping: Before mass production, a prototype of the PCB is created. This prototype allows engineers to test the board in real-world conditions and make sure everything functions as intended. It’s an opportunity to identify any design flaws or potential issues that might not be obvious in the initial design phase.
3. Fabrication: In this stage, the physical PCB is manufactured. This involves creating the actual board by printing the circuit patterns, etching away excess material, and adding layers if needed. The fabrication process also includes drilling holes for component mounting and applying finishes to protect the board and facilitate soldering.
4. Component Sourcing and Preparation: Once the PCB is fabricated, the next step is to source and prepare the electronic components that will be soldered onto the board. This can involve selecting components from various suppliers, ensuring they meet quality standards, and preparing them for assembly.
5. Assembly: The assembly process involves placing and soldering the electronic components onto the PCB. This can be done using automated equipment, such as pick-and-place machines and solder reflow ovens, or manually for smaller or more complex boards. Proper assembly is crucial for the board to function correctly and reliably.
6. Testing and Quality Assurance: After assembly, the PCBA undergoes thorough testing to ensure it meets all specifications and works as intended. This may include electrical testing to check for correct connections, functional testing to verify that the board performs its intended tasks, and visual inspections to catch any physical defects. Quality assurance is a critical step to identify and correct any issues before the board is used in final products.
7. Final Adjustments: Based on the results of testing, adjustments might be made to either the PCB design or the assembly process. This could involve modifying the board layout, changing component placements, or refining the assembly techniques.
8. Production and Delivery: Once the PCBA has passed all tests and adjustments, it moves into full-scale production. The final assemblies are produced in larger quantities and prepared for delivery to customers or integration into end products.
9. Support and Documentation: Finally, the development process includes providing support and documentation for the PCBA. This ensures that manufacturers and users have the necessary information for assembly, troubleshooting, and maintenance.
Last updated on August 27th, 2024 at 03:41 am