With the development of integrated circuits, the integration level and power density of semiconductor devices have significantly increased. Consequently, the heat generated by corresponding operations has dramatically risen. According to statistics, as high as 55% of high-power device failures are caused by heat. To address the heat dissipation issue in circuits, it is essential to first identify the components within the electronic packaging system that affect heat dissipation. As the carrier of integrated circuit chips, the substrate is in direct contact with the circuit, and thus the heat generated by the circuit needs to be dissipated outward through the substrate. In order to facilitate better heat dissipation for the circuit, the substrate material must possess high thermal conductivity.
Moreover, in fields such as new energy vehicles and modern rail transit, complex application conditions such as bumps and vibrations need to be considered during the use of high-power devices. This imposes higher requirements on the mechanical properties and reliability of the substrate material.
So, who can undertake such a heavy responsibility?
01 Silicon Nitride, the “top-notch” material in heat dissipation substrates
Compared to other materials, ceramic substrates demonstrate superior performance, thus selecting ceramic materials as substrates will have a broader prospect.
The ceramic materials that can be used as substrates mainly include: AlN, Al2O3, SiC, BeO, Si3N4, and so on. Although BeO ceramic substrates have high thermal conductivity and low dielectric constant, their powders are toxic and harmful to health, so they are rarely used nowadays. SiC is stable in nature, but it has high dielectric loss and low breakdown voltage, making it unsuitable for high-voltage working environments. Al2O3 ceramic substrates have the longest history of application and are the most mature, but due to the low theoretical and actual thermal conductivity of Al2O3, they cannot meet the heat dissipation requirements of large circuits and can only be used for small circuits. In comparison, AlN ceramics combine high thermal conductivity, good insulation, and low dielectric constant. However, AlN also has significant drawbacks that cannot be ignored, including its susceptibility to hydrolysis, insufficient strength and toughness, and brittleness. Therefore, there is an urgent need for a more stable ceramic material to compensate for the limitations of AlN.
performance comparison of several substrate materials
| Substrate material | Si3N4 | AIN | Al2O3 |
| Thermal conductivity/W/(m·k) | 80-100 | 170 | 20-30 |
| Fracture toughness/Mpad·m1/2 | 6.0-8.0 | 2.7 | 3.0 |
| Strength/Mpa | 600-800 | 350 | 400 |
| Current carrying capacity/A | ≥300 | 100-300 | ≤100 |
| Reliability/time | ≥5000 | 200 | 300 |
| Cost | relatively high | High | Low |
Compared with other materials, silicon nitride ceramics are recognized as the preferred material for high thermal conductivity ceramic substrates due to their high thermal conductivity (the thermal conductivity of its crystal can reach 320 W·m-1·K-1), low dielectric constant, non-toxicity, and a thermal expansion coefficient that matches that of single crystal Si.
Established in 2017, Zhejiang Zhengtian New Materials Technology Co., Ltd. (hereinafter referred to as “Zhengtian New Materials”) has achieved a significant breakthrough in the field of high-performance silicon nitride ceramic substrates through independent innovation. By mastering core technologies throughout the complete processing chain such as casting, cutting, punching, sintering, as well as post-processing CNC, grinding, polishing, and laser cutting, they have developed high thermal conductivity and high-performance silicon nitride ceramic substrate products.
02 Addressing the industry challenges of stable performance and large-scale production of Si3N4 substrates
While silicon nitride ceramic substrates are recognized as the best heat dissipation substrates in terms of comprehensive performance, two challenging issues need to be addressed in actual production: achieving “high thermal conductivity” and “sustained stable large-scale production.”
Zhengtian New Materials Si3N4
To achieve “high thermal conductivity,” high-quality silicon nitride powder and scientific, advanced preparation processes are indispensable. In terms of raw materials, Zhengtian New Materials selects high-quality silicon nitride powder globally, ensuring the “excellent genes” of silicon nitride substrates right from the source.
For silicon nitride substrates, achieving sustained and stable large-scale production is an industry challenge. It requires not only a stable process that ensures the avoidance of phenomena such as warping and cracking in the substrate but also the realization of efficient continuous operations.
Zhengtian New Materials casting workshop
With advanced processes and equipment, Zhengtian New Materials has already taken the lead in tackling high thermal conductivity and high-performance silicon nitride substrates. Currently, the company has achieved stable mass production with a thermal conductivity of up to 85W/(m·K) and a coefficient of thermal expansion of 2.7×10-6/℃. The products also feature excellent mechanical strength, good chemical stability, heat resistance, and large size (138mm*190.5mm) with low warpage (≤200μm) for silicon nitride ceramic substrates.
Dimensions of silicon nitride ceramic substrate products
| Main Project | Specification | Index |
| Substrate size (mm) | 100*100, 114.3*114.3, 138*190.5 | ±0.1mm |
| Thickness | 0.2, 0.25, 0.32, 0.635, 1.0 | ±10% NLT:±0.04mm 10% NLT:±0.04mm |
03 Fish leap in the boundless sea, and the birds soar in the vast sky
With the rapid proliferation of the third-generation semiconductor chips based on SiC in new energy vehicles and 5G technology, the demand for silicon nitride ceramic substrates has also entered a phase of rapid development.
According to projections, the global annual sales of electric vehicles will exceed 25 million units by 2025. Assuming the proportion of SiC power devices is 37% based on data estimated by multiple investment institutions, and considering the current usage of Si3N4 ceramic substrates for electric vehicles as one standard piece (7.5×5.5 inches) per vehicle, and two standard pieces per vehicle for large vehicles such as buses, the global additional annual demand for high thermal conductivity silicon nitride substrates in 2025 is estimated to be approximately 600,000 square meters.
This is just a market forecast within the new energy vehicle sector. In addition, the demand for high-performance silicon nitride ceramic substrates is also rapidly increasing in other fields such as charging systems and LED applications.
Through independent innovation, Zhengtian New Materials has achieved mass production of high-performance, large-size silicon nitride ceramic substrates. While comprehensively enhancing its own competitive strength, it has led the industry onto a path of independent and controllable high-quality development.
