1. Soon, the demand for petrol and diesel will vanish, and if all goes well, so will human drivers. The next time you’re in an Uber, don’t panic if there’s no one in the driver’s seat. That’s how technology works.

2. With the focus shifting towards automatic and electric vehicles, the automotive PCB industry is set to experience rapid growth. Printed circuit boards integrate all the sophisticated sensors and components necessary for the stable operation of vehicles.

3. If you envision the PCB as a chassis, with the car, engine, sensors, axle, and wheels forming the electronic components on the circuit board, it becomes easier to understand its role.

4. Reliability is paramount for automotive printed circuit boards. They must endure extreme environmental conditions and vibrations without any performance setbacks. Moreover, these circuit boards are expected to maintain full functionality over the long term.

5. Heat resistance and longevity distinguish automotive printed circuit boards from their counterparts. PCB manufacturers must adhere to the ISO/TS 16949 standard, which is based on the ISO 9001 automotive standard.

6. So, what are these specialized PCBs made of? What substrates are used, and do they have sufficient heat sinks? Let’s delve deeper.

7. Flexible PCBs – These boards are crafted from flexible plastic substrates such as PEEK, polyamide, or transparent polyester film. They can be twisted and bent, often utilized in car corners and curves.

8. Rigid PCBs – Composed of rigid plates made from FR4, these boards lack flexibility and are commonly employed in display screens and reverse camera screens.

9. Rigid-flex PCBs – A blend of rigid and flexible PCBs, these boards find application in lighting systems.

10. HDI PCBs – Featuring higher line density per unit area, thinner lines and spaces, and increased pad connection density, HDI boards accommodate more components and play a pivotal role in miniaturization. They are extensively used in infotainment systems.

11. LED PCBs – Utilizing aluminum substrates for heat dissipation, LED substrates are prevalent in car indicators, headlights, and brake lights.

1. Ceramic Substrate PCB – Ceramic substrates are composed of high-temperature co-fired alumina and aluminum nitride. These circuit boards are utilized in the engine compartment due to their ability to withstand high temperature changes.

2. PTFE PCBs – Polytetrafluoroethylene (PTFE) PCBs can endure high frequencies and are utilized in safety systems and/or radar technology.

3. Metal Core PCB – The metal core PCB comprises an aluminum base, specifically an aluminum alloy plate, on which the entire construction rests. The base functions as a radiator, making it suitable for heat transfer applications. Moreover, the metal core enhances electrical insulation and thermal conductivity. These boards are integrated into anti-lock braking systems (ABS).

4. Heavy Copper PCB – Automotive printed circuit boards utilize thicker copper (Cu) plates in both the outer and inner layers. These heavy copper plates are preferred over conventional ones because they can withstand high temperatures, frequencies, and currents. While the copper thickness of conventional circuit boards ranges from about 25 μm to 50 μm, heavy copper PCBs are 150 μm to 200 μm thick. They are commonly employed in security and signaling systems.

5. As more chips are integrated together, the materials binding them will play a crucial role.

6. Automotive PCBs must undergo rigorous thermal cycling tests, thermal shock tests, and temperature and humidity tests before being considered. Defects in the conductive anode filament (CAF) must be suppressed in the circuit board to prevent short circuits between the copper clad laminate (CCL) and the conductive trace line. The primary focus is on self-driving cars, although the safety of fully autonomous vehicles remains questionable. Nevertheless, systems with automatic braking have successfully initiated braking when rapidly approaching stationary vehicles. Vehicles increasingly rely on dependable printed circuit boards equipped with microchips that regulate engine performance and vehicle safety. All safety features, such as drowsy driver alarms and blind spot detection, necessitate PCBs.

7. The current developmental trajectory of the automobile industry will elevate the value of automotive electronic products. Regarding PCBs, the technology will need to accommodate multiple 100A high currents and gigahertz levels of information processing.

8. From a product performance standpoint, PCB functionality in automobiles surpasses its traditional role, necessitating the adoption of new concepts. While most signal processing technologies associated with PCBs can be transferred to the consumer product industry, adapting them for automotive use requires meeting stringent quality and reliability standards. For power electronic products, new PCBs must be developed to facilitate mass production for broader market penetration. However, thus far, only small batches of power electronics have been produced.

9. PCBs are pivotal components of these electronic systems. Given the demand for high-speed functionality, PCBs serve not merely as connectors between devices but as critical elements requiring special attention to prevent failure modes that could lead to short or open circuits. In a driverless car powered by hundreds of volts, thorough comprehension of PCBs is essential to ensure reliable operation. Common stressors and major failure modes of PCBs during production and product lifespan include environmental loads such as temperature cycling, bending, vibration, humidity, and combinations thereof.

10. PCB assembly (PCBA) environmental loads encompass reflow welding, selective welding, and pressing technologies.

11. Potential failure modes include cracks in copper-plated holes or inner copper layers, cracks in outer copper layers, cracks in microconductance holes, cracks in semi-cured pieces, cracks in solder masks, and electrochemical migration on PCB surfaces.

12. The specific requirements of automotive PCBs are influenced by their lifetime environmental loads, including temperature, humidity, and vibration. Diversified requirements will arise depending on the application, with electronics becoming smaller and closer to actuators (e.g., engines), necessitating materials capable of withstanding higher temperatures. Conversely, electronic devices like on-board computers require enhanced protection against external stresses, demanding longer service lives due to extended charging times and round-the-clock operation.

13. Functional requirements vary as well. While employing a PCB in an electric vehicle may present a cost-effective solution, the PCB must endure a vehicle environment with currents reaching several hundred amperes over a 1-million-hour lifespan and voltages up to 1000 volts.

14. To meet the signal processing demands of autonomous and connected cars, the automotive industry’s HDI (High-Density Interconnect) technology must advance significantly to accommodate thousands of processors and memory units with I/O and BGA (Ball Grid Array) pitches of less than 0.8 mm. High-speed requirements necessitate the utilization of new materials capable of meeting environmental demands, particularly humidity and temperature.

15. Failure modes induced by environmental temperature and humidity are critical in automotive electronics. While the industry has long concentrated on failures stemming from temperature cycling, the influence of humidity and temperature is equally crucial, notwithstanding the self-heating phenomenon evident in many car applications during operation. Preceding startup, cars may remain in humid environments for extended periods, allowing humidity to permeate electronic products through plastic or atmospheric compensation kits.

16. The impact of humidity on both the surface and internal structure of PCBs is a primary concern, with detailed studies conducted on potential failure modes. This article emphasizes failures resulting from temperature, humidity, and bias (THB). Even without condensation, elevated humidity levels can lead to electrical short circuits if materials are not carefully selected. Surface insulation resistance (SIR) may decrease, potentially causing electronic product failures. Our approach involves comprehensively understanding the temperature and humidity conditions within protective enclosures (metal or plastic) through simulation and experimental testing. Additionally, materials and design elements are identified under various temperature and humidity conditions using the SIR test method outlined in IPC-9202.

17. Within PCBs, humidity plays a critical role, with various failure modes potentially arising due to electrochemical migration (ECM). Conductive anode wire (CAF) or hollow fiber failure modes are recognized issues within the industry. It is imperative to investigate PCB or bulk material cracks in deformation areas and around plated through-holes. Resin cracking may occur due to temperature drops, high pressure, bending, and/or mechanical loading. Furthermore, the properties of PCB materials under high pressure warrant examination to ensure PCB insulation characteristics.

18. Simulating local environmental conditions such as temperature and humidity within PCBs in electronic systems is essential to ensure PCB substrate stability in automotive electronic products. Simulation conditions are compared against the load capacity and design of utilized materials. Life models aid in translating PCB identification test results into the actual conditions of electronic systems, enabling determination of appropriate design criteria distances within PCBs. Simulations also encompass CAF failure modes and other potential PCB cracks.

19. Presently, identification tests and life models are still under development. In instances where no applicable life model exists, materials or failure modes must be addressed through material limitations or stringent process controls (e.g., for hollow fiber failure modes).

20. High-speed applications, such as interconnectivity or image recognition (anticipated to reach up to 10 GHz in the future), radar (77 GHz), and signal processing, necessitate clearly defined substrates and design rule elements. Impedance-controllable PCB lamination and stringent PCB supplier process controls are standard in the consumer industry. The automotive sector must ensure high-quality signal integrity, power integrity, and electromagnetic compatibility. Material selection must account for stability in temperature, humidity, and bias, in addition to electrical properties, imposing constraints on future material selection and design rules. Identifying PCB suppliers capable of meeting the requirements for high-speed applications is imperative. Considering the electrical characteristics of PCB

1. The functions and requirements of automotive electronics are undergoing dramatic changes.

2. Solutions from the consumer product industry can be modified or adapted to meet automotive product requirements, while new ideas for mass production of power electronics must be developed.

3. To summarize, the escalating demands of automobiles include: