Application for Probe Pin Materials

Semiconductor integrated circuits are subjected to current-carrying tests at each of the front-end and back-end processes of the manufacturing process.
The current-carrying test in the front-end process is called a wafer test, and a probe card is used. Probe cards use cantilever or vertical probe pins.
The current-carrying test performed in the back-end process is called the final test, and a test socket is used. Pogo pin type probe pins are used for the test sockets.
We offer a lineup of various probe pin materials, as the performance required in terms of mechanical properties such as hardness and bendability, and electrical properties such as electrical resistivity, etc., vary depending on the application.

Types and Features of Probe Pins

■Cantilever Type

• Features: These probe pins are used for probe cards for testing wiring boards with a terminal structure that works on the principle of a cantilever beam. The tip of the probe pin is tapered into a needle shape and bent.
• Material requirements: Material hardness, linearity, electrical resistivity, bendability, etc.
• Wire diameter: Φ50～300µm

■Vertical Type

• Features: These are used for probe cards for testing wiring boards with a terminal structure that works on the principle of buckling stress. The tip of the probe pin is processed into a needle or hemispherical shape, depending on the board.
• Material requirements: Material hardness, linearity, electrical resistivity, bendability, etc.
• Wire diameter: Φ20～70µm

■Pogo Pin Type

• Features: These are also called spring probes or contact probes. They are used for electric current inspection of ICs, electronic components, and printed circuit boards. The tip is processed into a shape that corresponds to the object to be inspected.
• Material requirements: Material hardness, linearity, contact resistance, etc.
• Wire diameter: Φ500µm～1,000µm

Major Materials for Probe Pins

^*1 : Repeated bending times to failure at 0.10mm in dia. (acc. to in-house standard)
^*2 : ASTM B540 equivalent
^*3 : Patent registered
^*4 : TK-101 is only available in Φ1.00 mm

The above is just an example, and we can also accommodate compositions not listed here, so please contact us for more information.

*The above are the property values for wire materials. The property values differ between wire and sheet materials.
*Sheet materials can be supplied for TK-FS, SP-1, and TK-101. For details, please refer to “Suppliable sheet materials” at the bottom of this page.

Developed material: TK-FS

Low electrical resistivity, high bendability, and a wide range of hardnesses are all achieved simultaneously.

There was no material in our existing products that could simultaneously achieve the three qualities of high hardness, low electrical resistivity, and high bendability, but we have succeeded in solving this problem with this product, making it possible to use the same material for various types of probe pins. This material can be applied to a wide range of probe pin types, such as the cantilever type and the vertical type for wafer testing (front-end process) probe cards.

Features

• Achieves three qualities simultaneously: Vickers hardness of 500 or more, electrical resistivity of 7.0 µΩ·cm or less, and resistance to bending more than 10 times repeatedly (in-house standard).
• Our unique processing technology enables adjustment to a wide range of Vickers hardness (400 to 520).
• Higher elongation (10% to 25%) than TANAKA PRECIOUS METAL TECHNOLOGIES’ existing probe pin materials.

Performance of TK-FS (comparison with Major Materials for Probe Pins)

• Vickers Hardness vs Electrical Conductivity

  

• Elongation at Failure

  

• Features of TK-FS (High Bending Durability)

  

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• Schematic Diagram of Repeated 90° Bending Test

Developed material: TK-SK

■Applications

As a palladium alloy for probe pins, TK-SK exhibits maximum hardness of 640HV that makes it suitable for use in test socket applications mainly in the final continuity testing stage (back-end process).

■Features

Pogo pin-type probe pins are typically used in test sockets. During testing, the tip or plunger of the probe pin can become deformed due to friction from contact with substrates. Solder may also adhere to the plungers, needing regular cleaning, which further increases the risk of deformation due to friction.

High-hardness probe pins, like TK-SK, reduce wear-related deformation, leading to longer service life and lower maintenance costs for semiconductor test equipment.

Sheet material for vertical probe pins

Sheet materials can be supplied for TK-FS, SP-1, and TK-101 according to customers’ needs.