The tariff war between the United States and China continues to escalate, causing a significant impact on the semiconductor supply chain. Increased import costs and limited supply of key equipment such as photolithography and etching equipment are urgently driving strong domestic demand for breakthrough technologies and localized substitution. This demand runs through the entire industry chain, including the requirement for core components in the test chain.
The test probe market can be divided into semiconductor, PCB, ICT online test and other segments according to application. Among them, semiconductor test probes have the highest technical barriers due to their manufacturing difficulty, extreme precision in size, and complex electrical and mechanical performance requirements. For a long time, this market has been highly concentrated in the hands of a few imported brands such as YOKOWO from Japan, ECT from the United States and IDI. This leads to a key question: China's semiconductor packaging and testing link in the global market has occupied an important position, why in this seemingly small probe, still facing the "neck" of the dilemma?
Semiconductor test probes, is the size of a small but heavy responsibility of precision electronic components. Although the appearance of different uses, but usually consists of a needle, needle rod (or a complex structure containing a spring and sleeve) and other components, the overall size often reaches the micron level. Mainly used in semiconductor chip design verification, wafer testing, finished product testing links, as a bridge between the chip pins / solder balls and the test machine, the precise transmission of signals to detect the chip's various performance indicators.
It is not easy to process microstructures on a scale of only a grain of rice or even smaller, and it is even more difficult to ensure that the processed probes have excellent electrical conductivity (low contact resistance), mechanical strength (not easy to bend), and high wear resistance (long service life). General processes, such as photolithography combined with chemical etching or precision stamping and molding, in response to the micron-level precision, often face the problem of complex processes and high costs. Especially when processing high hardness or special materials such as tungsten, tungsten steel, palladium alloys, etc., they are prone to defects such as roughness of the contact surface, residual burrs, deformation of the material due to stress, and poor control of the shape of the tip. These defects directly affect the accuracy and reliability of probe testing, posing a severe test to the yield and cost control of the semiconductor industry.
Then there is no other way? At present, femtosecond laser processing technology shows great potential to solve the above problems. Take 0.1mm thick tungsten steel probe as an example: using femtosecond laser cutting, the top width is accurately controlled at 110.7μm±1μm, the processing process is stress-free and deformation-free, and the roughness is as low as Ra≤0.1μm, which fully demonstrates the excellent ability of femtosecond laser in microfabrication of high hard materials.
How does femtosecond laser do it?
1. "Cold" processing without damage: The pulse width of the femtosecond laser (10-¹⁵ seconds) is much smaller than the time of heat transfer within the material, and the energy acts on the material surface in a very short instant and directly vaporizes and strips it off, with almost no heat-affected zone. This means that high quality "cold" cuts can be achieved without recast layers, microcracks or thermally induced deformations, whether it is tungsten, tungsten steel with a high hardness and high melting point, or other metals, ceramics, polymers and other materials. This is essential to maintain the original physical properties of the probe material, ensuring stable electrical conductivity and long mechanical life during testing.
2, the ultimate precision microfabrication: femtosecond laser spot can be focused to the micron or even sub-micron level, combined with a high-precision motion control system, can achieve ± 1μm or even higher processing accuracy. Non-contact laser processing is not limited by the shape of the tool, through the control of the beam path, can flexibly cut the rib width of only a dozen microns of a variety of complex two-dimensional, three-dimensional contours of the probe structure, especially suitable for the development of new products and small batch, multi-species production model.
3, excellent cutting edge quality: probe contact surface and edge quality directly affects the stability of contact resistance and probe life. Femtosecond laser cutting edge is smooth, good verticality (no taper or controllable taper), roughness up to Ra ≤ 0.1μm, almost no burr, no slag. This not only enhances the contact stability and durability of the probes, but also eliminates the need for complicated subsequent treatment processes such as deburring and polishing.
Looking ahead, the industrialized application of femtosecond laser technology is continuing to deepen. This technological innovation provides new possibilities for overcoming the manufacturing difficulties of high-end test probes and other key components, and is expected to become an important technological support for breaking the long-term dominance of foreign brands in this field and enhancing the level of independent control of key components. This will play a positive role in promoting the resilience and competitiveness of China's semiconductor industry chain.
