Fingertip-Probe Card for Wafer Test Technology Equipment

The manufacturing process in the semiconductor industry can be divided into four steps: integrated circuit design, wafer manufacturing, wafer testing and wafer packaging. The so-called wafer test is to detect and eliminate the electrical properties of each grain on the wafer that does not qualify the grain. Let's take a look at the probe card for semiconductor wafer test and how it relates to LTCC/HTCC technology.

Fingertips of Wafer Test Equipment - Probe Cards

The primary method of wafer test is through the connection between the tester and the test bench. In the test process, the test machine can not directly measure the wafer to be tested, but through the probe card (probe card) and the wafer pad on the probe (probe pad) or with the formation of electrical contact collision contact, the probe measured test signals sent to the automatic test equipment (ATE) to analyze and judge, so as to obtain the electrical properties of each grain of the wafer.

Probe card is an important part of the semiconductor wafer test process, known as the test equipment "fingertips". Because each chip's pin arrangement, size, pitch change,wafer level testing frequency change, test current, test platform are not the same, so different chips need to customize the probe card. Currently, there is no one type of probe card on the market that can fully meet the testing requirements. At the same time, for a mature product, when the production volume increases, the test demand will also increase, and the consumption of the probe card will also increase exponentially.

Therefore, in recent years in the semiconductor to test through the rapid and healthy development of the market economy, driven by the global electronic probe card industry has also been a rapid development. According to VLSI Research's data analysis shows that in 2020 the global biological probe card sales enterprise scale is 2.206 billion U.S. dollars, in 2021 the global country semiconductor as a probe card output value of up to 2.368 billion U.S. dollars, to 2022 the world's largest semiconductor probe card output value of up to 2.608 billion U.S. dollars, the growth as well as the speed can be faster.

LTCC/HTCC technology in the application of the probe card

The probe card is the core component of wafer and wafer testing, providing the electrical connection between the wafer silicon and the test instrument. The STF substrate is the core component in the entire probe card. The Space Translation Matrix plays the role of electronic connection space translation and electrical signal transmission in the entire probe card, while providing sufficient mechanical /mechanical strength to support the hundreds to thousands of Newtons of force exerted during the test process.

The probe card (probe card body) is affected by the substrate material and is subject to deformation in multi-temperature (-55 ° C ~ 150 ° C) environments, especially at high and low temperatures. The probe is mounted directly to the probe card, and the deformation of the card causes an offset of the probe trace (the trace left when the probe touches the wafer contact point). The offset of the trace usually results in poor contact between the probe on the probe card and the wafer PAD,failure analysis which leads to test instability and affects the time and quality of the test. If the pointer offset is too large, the internal circuitry of the wafer will be damaged when the probe contacts the wafer PAD, resulting in scrap and financial loss. The probe card will also be rejected because it cannot be used for wafer testing.

Precision ceramic substrates have excellent electrical insulation, high thermal conductivity, high adhesion strength and large current carrying capacity. The temperature range of use is wide and can reach -55°C to 850°C. The coefficient of thermal expansion is close to that of silicon chips. It is one of the effective solutions for deformation in multi-temperature test environments.

In addition, with the maturity and enhancement of China's science and technology information technology, the chip to carry out the function can be gradually developed to increase the design research gradually formed complex, the chip input/output pin number also continued to increase. In order to be able to reduce the cost of enterprise production management, wafer size is also constantly learning to improve (such as 12-hour wafers), so the need for large-area detection with the probe card demand has gradually increased. Such large-area probe cards, due to the small pitch of the probe contact points, the structure is usually utilized in the network with an important line of the multilayer substrate (such as multilayer ceramic substrate) is set up in a number of probes and circuit boards between the travel line as a spatial conversion device.

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 lines 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). Eyes

Fingertip-Probe Wafer Test

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