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When contacting solder bump vertical probe card, a flat tip is always utilized; when contacting aluminum surfaces, a pointed tip is better since it will penetrate any oxide layer; and when contacting gold surfaces, both pointed and flat tips can be used.
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Understanding Vertical Probe Cards Semi Probes
Vertical-contact probe cards for wafer testing have several advantages, including full array testing and high parallel probing flexibility. Regardless of how the pads are arranged, several dice can be probed and examined at the same time. Parallel testing procedures can significantly cut costs.
Full -Array Probing • The widespread use of flip-chips and other array bumping techniques necessitates the contact of a large number of pads on a single square centimeter. Because of the physical limits imposed by the needle's horizontal arrangement, this application cannot be carried out with epoxy ring probe cards. • Increasing the throughput of a probing line lowers test costs and, lowers manufacturing costs. As a result, the goal is to test as many chips as feasible at the same time while reducing the number of touchdowns per wafer. The pads on the wafer must be placed in specific patterns for epoxy ring probe cards, due to physical limitations in the horizontal placement of the needles, parallel probing was adopted. Parallel probing with epoxy ring probe cards are frequently required to be factored into the chip design. This highlights a few drawbacks in the use of parallel probing.
High-Temperature Range • During the die test, the temperature range gradually widens. Temperatures of 0 to +125°C are necessary for numerous sorts of probing procedures. In this case, too, the traditional probing card technology demonstrates its limitations. In terms of thermal behavior, the construction of a needle card is exceedingly intricate and difficult to control. • Higher probing requirements can be met with vertical-contact probe cards. The buckling-beam principle is the foundation for a vertical probe card (or buckling wire). The bending or buckling of columns is defined by mathematical formulae as a function of loads applied to them. This relationship demonstrates that if a force is applied to the wire's end, the wire will bend and generate a spring force that is nearly independent of the wire's displacement. The force graph is constructed as a function of displacement for a buckling wire and a compression spring as a comparison. A significant non-linear spring characteristic is achieved, resulting in homogeneous force distribution over all contacts of a vertical probe card, in contrast to the spring concept of a needle card.
Vertical Probing Assembly • The ViPhead, which contacts the wafer (DUT), and the ViPconnection, which ensures good contact to the PCB, make up the vertical probing assembly. The ViPhead is made up of guide plates that are drilled to match the wafer footprint. The holes must be placed with exceptional precision to ensure high probe positioning accuracy of the buckling wires. The ViPhead's buckling beams align perfectly with the wires in the ViPconnector, ensuring great contact. This design also makes it easy to change the ViPhead for maintenance. The following capabilities were given significant consideration during development: high density probing; flexible, parallel probing; the high accuracy of contact points; and suitability for high-temperature ranges.
High-Density Probing • The vertical technology allows for the precise arrangement of thousands of contacts on a postage stamp's surface. Buckling beams (spring wires) that have been specially made are positioned in guide plates that have been perforated according to the footprint of the DUT. There are two types of vertical probe tip shapes: flat and pointy. When contacting solder bump vertical probe card, a flat tip is always utilized; when contacting aluminum surfaces, a pointed tip is better since it will penetrate any oxide layer; and when contacting gold surfaces, both pointed and flat tips can be used. Parallel probing reduces test time by a significant amount. If the contact pattern can be easily modified according to the intended parallel test strategy, the vertical probe card is especially ideal for parallel probing. This is accomplished by drilling a guide plate based on the DUT's footprints. Parallel testing must be factored into the wafer design.
In Short • ViProbe can be used to probe memory wafers in a variety of ways, including array probing, peripheral parallel probing, and multi-die probing. When it comes to array probing, the ViProbe is particularly well suited to full array probing, such as on flip-chip wafers. Semi Probe offers a wide range of probe cards and accessories, check out for details.
