Know About the Types of Probe Cards

The probe card is used to locate defective chips on wafers and remove them before further processing. Probe cards are available in a wide range of sizes and prices, from a few thousand to more than a quarter of a million US dollars. 

However, they all have the same basic components: a probe head made up of probe needles and something to keep them in place, a printed circuit board (PCB) to make connections to the tester, and a mechanism for connecting the probe head to the PCB. 

PCBs were formerly simple to manufacture, but the specifications have increased to the point that just a few manufacturers can meet the industry's cutting-edge needs.

The expansion of fifth-generation mobile communications networks (5G) and the goods that enable them have accelerated the development of smaller and denser semiconductor devices. As a result, inspecting and analyzing various electronic components, such as integrated circuits (ICs) and large-scale integrated (LSI) circuits, requires increased precision.

A probe card is a tool used to check silicon wafers during front-end LSI manufacture. A probe card is a circular printed circuit board (PCB) with connected probe pins or needles.

Each LSI chip, which is manufactured on a wafer, is electrically tested by simultaneously touching numerous probe pin tips on the PCB. 

Probe cards detect open and short circuits while also measuring electric current and high frequencies. A probe card is often attached to a wafer tester's prober and, during inspection, comes into contact with a wafer chip on a stage.

Probe cards can be classed based on their structure, including probe alignment and fixation. Two typical probe cards are shown below, along with their features.

Vertical (advanced) probe card

A vertical (advanced) probe card comprises a PCB and a block on which perpendicular probes are mounted. 

This sort of probe may be aligned in a grid or used to measure several chips. Maintenance is simple because the probes may be changed separately. Additionally, dents may be reduced, causing minimal harm to soldiers. However, the production costs are rather expensive, making aluminum electrode pads on wafers impractical.

Cantilever Probe Card

The needles on a cantilever probe card are composed of tungsten and other comparable materials. These needles are directly mounted on a PCB.

This kind may be created at a lesser cost than the vertical form. Its probes may also be positioned with narrower pitches to accommodate aluminum pads. When opposed to the vertical type, the cantilever type places more restrictions on pin placement and produces bigger dents. This kind also necessitates that operators devote time and effort to routine maintenance tasks such as repair and adjustment.

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