In the semiconductor materials industry manufacturing enterprise process, can be divided into IC design, wafer manufacturing process, wafer testing and wafer packaging as the four basic steps. One of the so-called wafer test, is the wafer on each grain can be analyzed and tested for electrical properties to detect and eliminate the unqualified grains on the wafer. Below through we come together to understand more about the students of China's semiconductor wafer test probe card, and electronic probe card and LTCC/HTCC technology development has its own how to contact.

Wafer test equipment "fingertips" - probe card

Wafer testing is mainly through the linkage between the tester and the probe station. In the test process, the tester can not be directly measured on the wafer to be tested, but through the probe card in the probe and the wafer on the pad or bump contact for electrical contact, and then the probe measured test probe signals sent to the automatic test equipment (ATE) to analyze the judgment, so as to get the wafer.

Probe card is an important part of the semiconductor wafer test process, is considered to be the "fingertips" of the test equipment. As each chip has a different pin arrangement, size, pitch, frequency, test current, test machine, different chips need to be customized probe card, there is no one probe card on the market can fully meet the test requirements. At the same time, for a mature product, with the increase in production, the test requirements will also increase, the consumption of probe cards will also be exponential growth.

Therefore, driven by the rapid development of the semiconductor test market in recent years, the global probe card industry is also growing rapidly. According to VLSI Research, in 2020, the global sales scale of probe cards will be $2.206 billion, in 2021, the global semiconductor probe card output value will reach $2.368 billion, and in 2022 it will reach $2.608 billion, a rapid growth rate.

Second, LTCC / HTCC technology in the application of the probe card

The probe card is the core component of wafer and wafer testing, providing an electrical connection between the wafer/silicon chip and the test instrument. In the whole probe card, the STF substrate is the core component. The Space Translation Matrix acts as an electronic link for pitch conversion and electrical signal transmission throughout the Probe Card while providing sufficient mechanical/mechanical strength to support hundreds to thousands of Newton forces applied during testing.

The probe card (probe station card body) is affected by the substrate material and is subject to deformation in multi-temperature (-55°C to 150°C) environments, especially at high and low temperatures. The probe is directly assembled on the probe card, and the deformation of the probe card causes the probe trace (the trace left when the probe makes contact with the wafer during wafer testing) to shift. The offset of the trace usually causes the probe on the probe card to make poor contact with the PAD (pad) of the wafer, resulting in unstable testing, affecting test time and quality. If the trace offset is too large, the contact between the probe and the PAD of the wafer will damage the internal circuitry of the wafer, resulting in scrap and economic loss. At the same time, the probe card will not be able to carry out wafer testing and scrap.

Precision ceramic substrate has excellent electrical insulation, high thermal conductivity, high adhesion strength and large current carrying capacity. It can be used in the temperature range of -55 degrees to 850 degrees Celsius with a coefficient of thermal expansion similar to that of silicon chips. It is one of the effective ways to solve the problem of deformation in multi-temperature test environments.

In addition, with the maturity and advancement of technology, the functions of the chip are gradually increasing, the design is becoming more complex, and the number of inputu002Foutput pins of the chip is also increasing. In order to reduce production costs, micromanipulator wafer sizes are also getting larger (e.g. 12-point wafers), so the demand for large-area probe cards for inspection is also gradually increasing. This large-area probe card, due to the small distance between the probe contact points, usually uses a multilayer substrate (e.g., a multilayer ceramic substrate) to arrange the circuitry between a plurality of probes and the circuit board as a spatial conversion device for the circuitry.

One form of the spatial translation matrix consists of stacked ceramic layers having metallized vias (passes through, passes through) that extend through the layers or wires and pass through the metallized traces between the layers. The channels and traces or circuits provide conductive paths from the probe pads to each PCB pad. Along a path through said layers and between said layers, said conductive path may extend from said probe pad spacing to said PCB pad spacing.

The ceramic substrate for the probe card is typically a ceramic multilayer substrate having a metallized monolayer or multilayer film. Multilayer ceramic substrates are made from high temperature or low temperature co-fired ceramics by laminating and co-firing multiple layers, often referred to as multilayer ceramics (MLC).