MLC
Due to the increase in the number of pins and the shrinking of the spacing between the horizontal probe card and the vertical probe card, the load capacity of the original circuit board has been exceeded, and a substrate must be added between the vertical probe card circuit board and the probe to deal with it. The ceramic substrate aims at higher substrate strength to overcome the expansion of the number of needles and DUT.
Depending on the design structure, NTK provides a complete circuit board, MLO, and Multi-Layer Ceramic (MLC).
MLC Substrate
MLC Carrier
Why are ceramic substrates used?
High hardness
Directly bearing the pressure of the probe test and causing no deformation or damage on the ceramic surface PAD.
| Material | CTE (ppm/℃) |
|---|---|
| Si | 3.4 |
| Ceramic (HTCC : Alumina) | 7.6 |
| Ceramic (LTCC : GM-1) | 4.1 |
| Organic (FR-4) | 15~20 |
Low thermal expansion rate
Compared with organic materials, the thermal expansion rate of the board is closer to that of the wafer (silicon). In high and low temperature tests, the probe will still contact the wafer at the correct position, avoiding errors caused by the difference in expansion rate.
Heat resistance
Ceramics are high-temperature sintered materials, with sintering temperatures close to 800~1200°C. In the most severe wafer tests, the shape and the physical and electrical properties of the ceramic substrate can be maintained in environments above 200°C.
