According to the PCB industry forecast and prospect analysis report released by Zhiyan Consulting, the proportion of high-end circuit board products in China is still relatively low. Especially in the field of packaging substrates, compared with Japan and other countries, domestic circuit board manufacturers produce mostly low-end, low-value-added products, and there is still a technological gap. The thermal conductivity of circuit boards is related to their material. Choosing different substrate materials is a current development trend; otherwise, ceramic substrates cannot stand out.

　 　Comparison of circuit board materials on the market

　　Currently, there are three types of PCB that are developing well in the market: FR-4 copper-clad laminates, metal substrates, and ceramic circuit boards. FR-4 circuit boards are the most widely used in the market, but the defect of FR-4 circuit boards is irreversible.

　　 (1) Advantages of FR-4 copper-clad laminates:

　　1. No insulation layer used.

　　2. Mass production.

　　3. Fast forming speed.

　　4. Low price.

　 　There are about 12 defects:

　　1. Common thickness tolerances include thicker in the middle and thinner on the four sides, or thicker on one side and thinner on the other, which will affect the processing of the PCB. Uneven thickness will affect the depth of the slot and the resistance of the substrate. For more precise printed circuit boards, excessive board thickness will cause uneven tightness during the insertion and removal of the entire machine, resulting in poor contact and affecting the performance of electronic devices. For multilayer printed circuit boards, the accumulation of thickness tolerances may cause the overall thickness of the entire board to be too poor, resulting in scrap products. It cannot meet the tolerance requirements for the bottom thickness of high-voltage boards for high-precision products such as test benches.

　　2. Substrate vibration: Affects the solderability, electrical insulation, and other performance of the substrate, and cannot be used as a genuine product.

　　3. Substrate delamination: This phenomenon is not inapplicable, but it cannot be a Class A product.

　　4. White spots and white lines on the substrate: Seriously affect the manufacturing quality of the PCB.

　　5. Exposed substrate graphics: Cause a decrease in insulation performance and seriously affect the quality of the PCB.

　　6. Substrate impurities and black spots: In addition to affecting the appearance of the product, there are other impacts. Currently, what can be done is

　　7. Copper foil creases: Boards with such creases are not allowed to be used in PCB production.

　　8. Glue spots: These are cured resins that cannot be corroded during production, seriously affecting the insulation between conductors, so they cannot be used in PCB production.

　　9. Pitting: Has a great impact on the quality of PCB products, and may cause or appear to cause line blockage.

　　10. Pinholes: Will cause the image to be rough, with traces of kerosene leakage.

　　11. Copper foil oxidation: Slight oxidation will not affect the quality of PCB products, but it should be prevented as much as possible. Severe oxidation may make it difficult to corrode and clean the PCB process, and it cannot be used in the production of copper-clad laminates.

　　12. Copper foil highlights: Because the anti-oxidation layer at this point is damaged, this point is easily oxidized during product storage, which has a negative impact on the PCB. For larger highlights, the copper and tin here may be thinner than other places, which will also affect the manufacturing quality of the PCB.

　　13. Light recess, as long as it appears once, many will appear continuously. Manufacturers will not accept this phenomenon.

　　14. Steel plate pattern: When copper-clad laminates with steel plate patterns are used for fine-line board production, ripples will appear on the surface of the copper foil, which is obviously not allowed.

　　15. Uneven filling affects the insulation and mechanical processing performance of the PCB.

　　16. The problem of insufficient substrate curing reduces the mechanical strength of the substrate, the white circle of the substrate punching is more obvious, and there are more burrs on the edge.

　　17. Common defects of prepreg.

　　18. CAF (substrate anti-ion migration problem) will cause a large error in the copper ion thickness coverage rate during PCB processing.

　　 (2) Advantages of aluminum substrates:

　　1. More suitable for SMT mounting technology;

　　2. Meets RoHS requirements;

　　3. Effectively handles heat dissipation, thereby reducing the operating temperature of the module, extending its service life, and improving reliability;

　　4. Reduced size, reducing the mounting area of heat sinks and other hardware (including thermal interface materials), reducing product size, and lowering hardware and assembly costs;

　　5. Good mechanical durability, superior to some ceramic circuit boards made with simple processes.

　　 Disadvantages of aluminum substrates:

　　1. Higher cost: Compared with other inexpensive products, the price of aluminum substrates accounts for more than 30% of the product price, which does not meet the standard.

　　2. Currently, the mainstream can only make single-sided boards, and it is difficult to make double-sided boards. Currently, domestic single-sided boards are relatively proficient, and the processes and technologies of multilayer boards are relatively mature abroad, and more people will come to learn about them.

　　3. The products produced are prone to problems in electrical strength and withstand voltage: This problem is mainly related to the material itself.

　　4. Aluminum substrate will affect the withstand voltage index of the board; the withstand voltage value of the whole lamp does not meet the standard; circuit design and structural design both affect the withstand voltage, and the measured withstand voltage of some aluminum substrates used in LED lamps on the market cannot exceed 800V.

　　5. The thermal conductivity test method and test results are inconsistent, and the thermal conductivity of the dielectric layer is different from that of the finished aluminum substrate.

　　6. The material specifications of aluminum-clad laminates are not unified, including CPCA industry standards, national standards, and international standards.

　　7. If the copper foil thickness does not meet the standard, it will also cause circuit burnout and power supply explosion.

　　8. More and more PCB manufacturers are producing counterfeit products, disrupting the market, cutting corners, and using inferior products as superior ones.

　　(3) Advantages of ceramic circuit boards:

　　1. Strong durability.

　　2. Excellent high-frequency characteristics.

　　4. High thermal conductivity: This is related to the material itself; ceramics have an advantage over metals and resins.

　　5. Good chemical stability, better shock resistance, heat resistance, pressure resistance, internal circuits, and MARK points than general circuit boards.

　　6. More accurate printing, chip placement, and soldering.

　　Disadvantages of ceramic boards:

　　1. Fragile: This is one of the major drawbacks; currently, only small-area circuit boards can be produced.

　　2. Expensive: With the increasing demands of electronic products, ceramic circuit boards only meet the requirements of some high-end products; low-end products will not use them at all.