Tungsten Needles and Tungsten Rhenium Needles Used in the Construction of Probe Cards

Tungsten needle, also named tungsten pin, mainly refer to thin tungsten rod or thin tungsten rod with sharp tip. Their properties are basically the same, but uses are different. Mostly, their diameters are usually below 2mm and lengths range from 15mm to 100mm. 

For thin tungsten rod, it is mainly used as an electrode for argon arc welding. During welding, an arc will be generated between the tungsten electrode and the workpiece, and under the action of the arc heat, the filler metal will melt with the workpiece to form a weld.

Tungsten rod with pointed tip can be simply understood as pure tungsten or tungsten alloys with pointed tips at one end or both ends, which are mainly used as instrument probes, such as digital four-probe testers. The distance between the four tungsten needles in the digital four-probe tester cannot be too long or too short, and each one has a different function.

The rods with pointed tip are usually called tungsten probes. Most integrated circuits are tested using cantilever blade and epoxy ring probe cards. Contact resistance, balanced contact force and card life are directly dependent on probe material and shape. Therefore, a critical design step for any card is the specification of the probes.

In blade cards, probes are soldered to metal or ceramic blades, which in turn are mounted to a printed wiring board (PWB) to match the contact land pattern of the device under test. For epoxy ring cards, the probes are arranged in a contact pad pattern, embedded in the epoxy ring, and the bake-hardened assembly is bonded and soldered to the PWB.

The use of tungsten rhenium (WRe) needles in probe card construction has grown considerably over the past two years. Traditionally, tungsten (W) probes have been used for many reasons - excellent stiffness, hardness and wear properties.

The growing acceptance of WRe as an alternative probe material seems to be mainly due to the good user experience. Chinatungsten/CTIA GROUP found both tungsten and WRe materials were effective in scrubbing the contact pads. But due to its higher hardness, the WRe probe exhibits excellent resistance to tip fouling and better overall lifetime characteristics.

Chinatungsten/CTIA GROUP are professional manufacturers of tungsten for more than two decades, please feel free to contact us if you have any purchasing plans for tungsten and tungsten rhenium needles. 

• < Prev
• Next >