Semiconductors

Bow and warp of wafers

Confocal chromatic sensors scan the wafer surface to detect bow, warp and distortion. Providing a measuring rate of 70 kHz, confocalDT controllers enable highly dynamic measurements, allowing the wafer to be inspected within short cycle times.

Detection and measurement of saw marks

For automatic detection and measurement of saw marks, confocal chromatic sensors from Micro-Epsilon are used. The fast surface compensation feature of the controller regulates the exposure cycles in order to achieve maximum signal stability on surfaces with varying reflection characteristics. As confocal sensors from Micro-Epsilon can tolerate a large tilt angle and offer an extremely small light spot, they reliably detect saw marks and other indentations on the wafer.

Recognition and measurement of bumps on silicon wafers

Confocal chromatic displacement sensors from Micro-Epsilon are used to inspect bumps. They generate a small light spot onto the wafer, while reliably detecting the smallest of parts and structures at high resolutions. Therefore, shape and dimensions of bumps are reliably measured for contacting purposes.

Transparent layers & adhesive beading

Confocal chromatic sensors are used for one-sided layer thickness measurements. The confocal measuring principle enables the evaluation of several signal peaks, allowing the thickness of transparent materials to be determined. With the multi-peak measurement feature, the confocalDT controller reliably determines the thickness of protective coatings and paint layers.

Wafer thickness measurement / TTV

Confocal chromatic sensors measure the thickness deviation (Total Thickness Variation) and the wafer thickness from both sides. Based on the wafer thickness profile, bow and warp of the wafer can be detected. High measuring rates enable thickness detection of the entire wafer in short cycle times.

Inspection of cracks and breakages

Confocal chromatic sensors from Micro-Epsilon are used to detect cracks and other defects on the wafer. They reliably detect surfaces with varying reflection characteristics due to a fast surface compensation feature. An extremely small light spot and high resolution enable the reliable detection of the finest of anomalies on the wafer.

Positioning of the lens system in lithography machines

Non-contact, inductive displacement sensors (eddy current) measure the position of lens elements in order to achieve the highest possible imaging accuracy. Depending on the lens system, displacement sensors from Micro-Epsilon are used to detect movement and position in up to 6 degrees of freedom. Providing a high frequency response, eddyNCDT sensors also monitor highly dynamic movements of the lens system.

Positioning the wafer stage

Non-contact sensors from Micro-Epsilon are used for position monitoring of the wafer stage, where they measure highly dynamic XYZ movements of the stage which accelerates very rapidly. Capacitive and inductive (eddy current) sensors achieve nanometer resolution in order to ensure that the wafer is precisely positioned for the exposure process. These innovative sensors can be used in vacuum applications and are insensitive to strong magnetic fields.

Nanometer positioning in lithography machines

To illuminate individual components on the wafer, the lithographic devices move the wafer to the respective position. Capacitive displacement sensors measure the position of the travel path in order to enable nanometer-accurate positioning.

Positioning of masks in lithography

Lithography processes require high resolution and long-term measurement of machine movements in order to achieve maximum precision. High resolutions enable nanometer-precise positioning of masks using capacitive sensors from Micro-Epsilon. Their vacuum-suitable design enables the sensors and cables to be used in ultra-high vacuum.

Recommended sensor technology

capaNCDT 6200

High precision thickness measurement of silicon wafers

Capacitive displacement sensors are used for the exact thickness measurement of wafers. Two opposing sensors detect the thickness and also determine other parameters such as deflection or sawing marks. The position of the wafer in the measuring gap may vary.

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