From design to application, a chip must undergo extremely rigorous chip probing (CP) and final test (FT). In these two key links, the spring thimble plays an indispensable role:
Wafer test (CP): Before wafer cutting, the thimble on the probe card (a precision device integrated with hundreds of spring thimbles) will directly contact the tiny solder pad on the wafer, preliminarily screen the chip performance, and effectively reduce the subsequent packaging costs.
Final test (FT): After the chip is packaged, it will be put into the test socket. The spring thimble in this test seat serves as a temporary but stable bridge to connect the chip (DUT) with expensive automatic test equipment (ATE) for final performance verification.
System level test: After the chip is installed on the PCB board, the “needle bed” jig with integrated spring thimble is also often used for online test (ICT) to find assembly defects in production. With the continuous evolution of chip technology (such as AI, 5G, automotive electronics and other needs), the spring thimble technology itself is also developing rapidly. Behind an advanced probe is the combination of materials science, precision manufacturing and microwave engineering.
Challenges brought by advanced manufacturing process in technical dimension Solution and technical evolution of spring thimble
The contact spacing of the miniaturized chip is reduced to 0.35mm or even lower, and the traditional thick probe cannot be accurately aligned. The tip spacing can be 0.07mm-0.14mm, and the bevel offset tip design is used to precisely match the micro contact.
High frequency high-speed 5G, millimeter wave chips require the test interface to have extremely low loss and signal integrity. Traditional probes are prone to signal distortion and crosstalk. The probe can work at 50GHz or even higher. Its key technology evolution includes the use of 45 ° inclined coplanar waveguide (CPW) structure to reduce signal reflection, and the integration of innovative isolation structure to reduce crosstalk.
High reliability and long-life mass production testing requires that the probe undergo hundreds of thousands of times of plugging and unplugging, and that the performance is not degraded. The insertion and removal life of more than 500000 times has become a common standard for high-end probes. To achieve this goal, the industry adopts the Kelvin four wire structure to eliminate contact resistance error, develops a scratch needle with self-cleaning function to break through the oxide layer, and develops an ultra-low temperature test fixture (as low as 54K/-219 ℃) to meet the needs of frontier fields such as quantum computing.
New materials and new processes need to achieve the best balance between conductivity, hardness, wear resistance and cost. Materials have evolved from traditional beryllium copper (BeCu) to more wear-resistant palladium alloy (Palladium) and palladium nickel alloy (PdNi); In manufacturing, in addition to precision CNC turning, MEMS (Micro Electro Mechanical System) technology has also been introduced to manufacture more precise probes.
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Post time: Apr-16-2026