The probe card is the interface between the chip under test and the test machine in wafer test. It is mainly used to conduct preliminary measurements of the electrical performance of the chip before chip slicing and packaging, and to screen out bad chips before proceeding packaging engineering. It is a key tool for chip functional verification testing and industrial testing.

• Blade Probe Card: Dozens to hundreds of micro-cantilever-shaped probes are fixed on the PCB board through epoxy resin rings, and are laid out according to the positions of the pins on the chip to be tested.
• Cantilever Probe Card: Similar to the blade probe card, the micro-cantilever probe is placed on the upper surface of the PCB board.
• Vertical Probe Card: A probe that can be bent in the vertical direction is used to replace the cantilever beam and blade-like structure, which can save space and increase the density and quantity of probes.
• Membrane Probe Card: The micro-cantilever-shaped probe is fixed on the PCB board through the holes in the film.
• MEMS Probe Card: Taking advantage of MEMS technology, probe cards are used to test the high accuracy and reliability of logic devices and microprocessors.

Probes are an important part of the probe card. They are divided according to probe materials. Common ones include tungsten probes, cymbal copper probes, and tungsten-rhenium alloy probes.

• Tungsten probes have high strength and low contact resistance, but are highly destructive; beryllium copper alloy provides lower contact resistance than tungsten, but the probe hardness is not as good as tungsten needles, and the tip wears faster;
• The contact resistance of tungsten-rhenium alloy (97%-3%) is slightly higher than that of tungsten, and its fatigue resistance is similar. However, the lattice structure of tungsten-rhenium alloy is closer than that of tungsten, and the plane at the top of the probe is smoother, which can ensure wear resistance. Damage, not easy to stain.

Generally, the contact resistance of comprehensive tungsten-rhenium alloy probes is relatively stable, taking into account both hardness and flexibility and is not prone to probe deflection. Therefore, tungsten-rhenium alloy probes are commonly used probes with good performance at this stage.

• Pay attention to avoid mechanical damage when making contact: The contact part of the probe card is easily susceptible to mechanical damage. When using it, you need to pay attention to avoid damage such as impact or bending.
• Prevent high temperature and humid environments: The probe card needs to be used in a dry and temperature-friendly environment to avoid damage caused by high temperature and humid environments.
• Pay attention to anti-static interference: When using the probe card, you need to pay attention to electrostatic interference to avoid affecting the circuit.
• Pay attention to grounding issues: When testing the circuit board, the probe card needs to be grounded correctly to avoid errors caused by poor grounding.
• You need to be careful when using it: The test accuracy of the probe card is high, so you need to be careful when using it to avoid affecting the test results.

The probe card needs to test the following aspects:

• Electrical performance testing of the probe card: including testing the resistance, insulation resistance, contact resistance, and other parameters of the probe to ensure that the probe card can accurately transmit signals and avoid short circuits, open circuits, and other faults.
• Mechanical performance test of the probe card: including testing the elasticity, wear resistance, insertion and extraction force, and other parameters of the probe to ensure that the probe card can reliably contact the chip during use and avoid damage between the probe card and the chip. damage.
• Stability test of the probe card: including testing the performance stability of the probe card after long-term use and the consistency under different temperature and humidity conditions to ensure that the probe card can remain stable during use. performance.
• Probe card reliability testing: including testing the reliability of the probe card after multiple uses, as well as the consistency and stability under various environmental conditions, to ensure that the probe card can reliably be used during use. Test the performance of the chip.

The chip industry’s demand for probe cards continues to change. The distance between adjacent probe tips has grown from millimeters to tens of microns. The leakage requirements of probes have also gradually increased. The test frequency of probe cards has developed from ordinary low-frequency testing to ultra-high-frequency testing. High-frequency testing, etc. The demand for chip testing has caused the probe card manufacturing industry to face technical challenges such as high-density probe distribution, large-area array testing, and high-frequency testing.