Printed circuit boards used in 5G applications are designed to prevent transmission loss. To do this, the copper circuit’s surface roughness is minimized.
Image of a printed circuit board cross section
Conventionally, the wettability on the copper foil side was used to control the bond quality of the base copper foil and the organic material. However, demand for surface roughness evaluation of the copper foil continues to increase as the functionality of flexible printed circuit (FPC) boards improves.
Surface Acoustic Wave Device Wafers
Surface acoustic wave devices use vibrations transmitted through a solid surface to extract certain signals from background radio waves. In high-frequency 5G applications, the back of the wafer is roughened to scatter undesirable frequencies.
Roughness Measurement Challenges
Conventional roughness measurement using a contact stylus can damage the sample’s surface and is not sensitive enough to detect minute roughness changes.
Laser Microscope Roughness Measurement
The OLS5100 3D measuring laser microscope enables highly accurate, non-contact surface roughness measurement of copper foil and wafers. It’s capable of high-resolution surface roughness measurements in very small areas without damaging the sample’s surface.
3D measurement of copper foil
Copper foil for medium and low frequencies
High-frequency (5G) copper foil
High-resolution image of copper foil surface
3D image of copper foil surface
Roughness measurement of the back surface of lithium tantalate wafer after copper roughening
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