In the manufacturing process of the semiconductor industry, it can be mainly divided into four steps: IC design, wafer manufacturing process, wafer testing, and wafer packaging. Wafer testing involves testing the electrical properties of each grain on a wafer to detect and eliminate unqualified grains. Let's take a look at the connection between probe cards and LTCC/HTCC technology.

1、 The "Fingertip" of Wafer Testing Equipment - Probe Card

The main method of wafer testing is through the linkage between the testing machine and the probe station. During the testing process, the testing machine station cannot directly measure the wafer being tested, but instead forms electrical contact through the probe in the probe card and the solder pad or bump on the wafer, and then sends the test signal measured through the probe to the automatic testing equipment (ATE) for analysis and judgment, Therefore, the electrical characteristics test results of each grain on the wafer can be obtained.

Probe cards are important components that need to be used during semiconductor wafer testing, and are considered the "fingertips" of testing equipment. Customized probe cards are required for different chips, and currently there is no type of probe card on the market that can fully meet testing needs. Meanwhile, for a mature product, as production increases, the testing demand will also increase, and the consumption of probe cards will also multiply.

2、 Application of LTCC/HTCC Technology in Probe Cards

Probe cards are the core components of wafer and wafer testing, providing electrical connections between the wafer/silicon chip and testing instruments. In the entire probe card, the spatial conversion substrate (STF substrates) is the core component, playing the role of electronic connection spacing conversion and electrical signal transmission, while providing sufficient mechanical/mechanical strength to support the applied force of hundreds to thousands of Newtons during the testing process.

The probe card is affected by the substrate material and can deform in environments with multiple temperature ranges (-55 ℃~150 ℃), especially at high and low temperatures. The probe is directly assembled on the probe card, and the deformation of the probe card can cause the offset of the probe needle trace, resulting in poor contact between the probe on the probe card and the PAD (pad) of the wafer, leading to unstable testing and affecting testing time and quality. Excessive needle offset can damage the internal circuit of the wafer, leading to scrap and economic losses.

With the maturity and improvement of technology, chip functions gradually increase, design becomes increasingly complex, and the number of chip input/output pins continues to increase. In order to reduce production costs and continuously increase wafer size, the demand for probe cards for large-scale detection is gradually increasing. Due to the small spacing between probe contact points, multi-layer substrates with circuits are usually used in structures as spatial conversion devices between multiple probes and circuit boards.

The ceramic substrate used for probe cards is generally a single layer thin film with metallization or a multi-layer ceramic substrate with multiple layers of thin films. The multi-layer ceramic substrate is made by co firing high-temperature or low-temperature co fired ceramics through multiple layers of lamination and co firing, commonly referred to as a multi-layer ceramic space conversion matrix (MLC).

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