New interferometer for high-precision wafer thickness measurement

The IMS5420-TH white light interferometer opens up new perspectives in industrial thickness measurement of monocrystalline silicon wafers. Due to its broadband superluminescent diode (SLED), the IMS5420-TH can be used for undoped, doped and highly doped SI wafers. The thickness measuring range extends from 0.05 up to 1.05 mm. The measurable thickness of air gaps is even up to 4 mm.

In semiconductor production, highest precision is essential. An important process step is the lapping of the blanks, which are thereby brought to a uniform thickness. In order to continuously control the thickness, the interferoMETER IMS5420 series white light interferometers were developed.

These each consist of a compact sensor and a controller housed in a robust industrial-grade enclosure. Active temperature control integrated in the controller ensures high stability of measurements.

The interferometer is available as either a thickness or a multi-peak thickness measuring system. The multi-peak thickness measuring system can measure the thickness of up to five layers, e.g., wafer thickness, air gap, film and coatings >50 µm. For thickness measurements in difficult environmental conditions, the IMS5420IP67 controller is available with IP67 protection rating and stainless steel housing as well as matching fiber optics and sensors.