Today, with the rapid development of the semiconductor industry, IC testing, as a crucial link to ensure the performance of chips, its accuracy and stability directly affect the yield rate of chips and the competitiveness of the industry. As the chip manufacturing process continues to advance towards 3nm, 2nm and even more advanced nodes, the requirements for core components in IC testing equipment are becoming increasingly strict. Granite bases, with their unique material properties and performance advantages, have become an indispensable "golden partner" for IC testing equipment. What technical logic lies behind this?
I. The "Inability to Cope" of Traditional Bases
During the IC testing process, the equipment needs to precisely detect the electrical performance of the chip pins, signal integrity, etc. at the nanoscale. However, traditional metal bases (such as cast iron and steel) have exposed many problems in practical applications.
On the one hand, the coefficient of thermal expansion of metallic materials is relatively high, usually above 10×10⁻⁶/℃. The heat generated during the operation of IC testing equipment or even slight changes in ambient temperature can cause significant thermal expansion and contraction of the metal base. For instance, a 1-meter-long cast iron base can expand and contract by up to 100μm when the temperature changes by 10℃. Such dimensional changes are sufficient to misalign the test probe with the chip pins, resulting in poor contact and subsequently causing distortion of the test data.
On the other hand, the damping performance of the metal base is poor, making it difficult to quickly consume the vibration energy generated by the operation of the equipment. In the scenario of high-frequency signal testing, continuous micro-oscillation will introduce a large amount of noise, increasing the error of signal integrity testing by more than 30%. In addition, metal materials have a high magnetic susceptibility and are prone to coupling with the electromagnetic signals of the testing equipment, resulting in eddy current losses and hysteresis effects, which interfere with the accuracy of precise measurements.
Ii. The "Hardcore Strength" of Granite Bases
Ultimate thermal stability, laying the foundation for precise measurement
Granite is formed by the tight combination of mineral crystals such as quartz and feldspar through ionic and covalent bonds. Its coefficient of thermal expansion is extremely low, only 0.6-5×10⁻⁶/℃, which is approximately 1/2-1/20 of that of metallic materials. Even if the temperature changes by 10℃, the expansion and contraction of the 1-meter-long granite base is less than 50nm, nearly achieving "zero deformation". Meanwhile, the thermal conductivity of granite is only 2-3 W/(m · K), which is less than 1/20 of that of metals. It can effectively prevent the heat conduction of the equipment, keep the surface temperature of the base uniform, and ensure that the test probe and the chip always maintain a constant relative position.
2. Super strong vibration suppression creates a stable testing environment
The unique crystal defects and grain boundary sliding structure inside granite endow it with a strong energy dissipation capacity, with a damping ratio of up to 0.3-0.5, which is more than six times that of the metal base. Experimental data show that under the vibration excitation of 100Hz, the vibration attenuation time of the granite base is only 0.1 seconds, while that of the cast iron base is 0.8 seconds. This means that the granite base can instantly suppress the vibrations caused by equipment start-up and shutdown, external impacts, etc., and control the vibration amplitude of the test platform within ±1μm, providing a stable guarantee for the positioning of nanoscale probes.
3. Natural anti-magnetic properties, eliminating electromagnetic interference
Granite is an diamagnetic material with a magnetic susceptibility of approximately -10 ⁻⁵. The internal electrons exist in pairs within chemical bonds and are almost never polarized by external magnetic fields. In a strong magnetic field environment of 10mT, the induced magnetic field intensity on the surface of granite is less than 0.001mT, while that on the surface of cast iron is as high as more than 8mT. This natural anti-magnetic property can create a pure measurement environment for IC testing equipment, protecting it from external electromagnetic interference such as workshop motors and RF signals. It is particularly suitable for testing scenarios that are extremely sensitive to electromagnetic noise, such as quantum chips and high-precision ADCs/Dacs.
Third, the practical application has achieved remarkable results
The practices of numerous semiconductor enterprises have fully demonstrated the value of granite bases. After a globally renowned semiconductor testing equipment manufacturer adopted a granite base in its high-end 5G chip testing platform, it achieved astonishing results: the positioning accuracy of the probe card increased from ±5μm to ±1μm, the standard deviation of the test data decreased by 70%, and the misjudgment rate of a single test dropped significantly from 0.5% to 0.03%. Meanwhile, the vibration suppression effect is remarkable. The equipment can start the test without waiting for the vibration to decay, shortening the single test cycle by 20% and increasing the annual production capacity by over 3 million wafers. In addition, the granite base has a lifespan of over 10 years and requires no frequent maintenance. Compared with metal bases, its overall cost is reduced by more than 50%.
Fourth, adapt to industrial trends and lead the upgrade of testing technology
With the development of advanced packaging technologies (such as Chiplet) and the rise of emerging fields like quantum computing chips, the requirements for device performance in IC testing will continue to rise. Granite bases are also constantly innovating and upgrading. Through surface coating treatment to enhance wear resistance or by combining with piezoelectric ceramics to achieve active vibration compensation and other technological breakthroughs, they are moving towards a more precise and intelligent direction. In the future, the granite base will continue to safeguard the technological innovation of the semiconductor industry and the high-quality development of "Chinese chips" with its outstanding performance.
Choosing a granite base means choosing a more accurate, stable and efficient IC testing solution. Whether it is the current advanced process chip testing or the future exploration of cutting-edge technologies, the granite base will play an irreplaceable and significant role.
Post time: May-15-2025