ABOUT WAFER BOW AND WARP MEASUREMENT SYSTEMS
Thickness Measurement for Metrology Systems ASTM F657: The distance through a wafer between corresponding points on the front and back surface. Thickness is expressed in microns or mils (thousandths of an inch). Total Thickness Variation (TTV) ASTM F657: The difference between the maximum and minimum values of thickness encountered during a scan pattern or series of point measurements. TTV is expressed in microns or mils (thousandths of an inch). ASTM F534 3.1.2: The deviation of the center point of the median surface of a free, unclamped wafer from the median [...]
LITHOGRAPHY OPTICS POSITION FOCUS
Industry Semiconductor Applications Photolithography Using Capacitance Sensors Measurement Type Positioning Description One specific area where capacitance systems excel is high resolution focusing of complex lens systems such as those found in atomic force microscopes, vision inspection machines and photolithography tools. In a multi-million dollar photolithography tool, high accuracy, nanometer resolution and maximum thermal stability are absolutely critical to maintain proper focus and obtain integrated circuit line widths as small as 45 nanometers. Additionally, most systems demand low power consumption and maximum heat dissipation to eliminate any adverse affects from [...]
GAAS SUBSTRATE THICKNESS MEASUREMENT
Industry Semiconductor Applications Gaas Substrate Thickness Measurement Measurement Type Thickness Description Measuring Thickness of Wafers with Different Chemistries Introduction: Silicon wafers are ordinarily highly conductive and easy to measure with standard capacitive displacement sensors (See MTI’s Proforma 300i). Measuring the thickness of GaAs wafers that have high bulk resistivity (>10k Ohm/cm) is a little more difficult because the wafers act as non-conductive insulators in a capacitive sensor’s measuring field. Fortunately, MTI has a solution to this problem. Solution: It’s possible to measure the thickness and TTV of high resistivity semiconducting wafers (like GaAs) using non-contact capacitive [...]
Application Note: Replace Three Legacy Systems with One: Modernizing Aerospace/Defense Test Cells with PBS eXpress GalleryApplication Note: Replace Three Legacy Systems with One: Modernizing Aerospace/Defense Test Cells with PBS eXpress
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Application Note: Replace Three Legacy Systems with One: Modernizing Aerospace/Defense Test Cells with PBS eXpress
Introduction Many military/defense and commercial aerospace test cells still rely on aging analog instruments that, while functional, introduces risk through calibration challenges, legacy components, and lack of digital data access. As testing demands evolve, the industry is moving toward compact, digital platforms that simplify workflows and improve data usability. A Vitrek customer faced this challenge across multiple engine test cells. Their solution: replace two legacy systems with a single PBS eXpress R+, enabling faster setup, digital data acquisition, and automated reporting. The Challenge The customer’s test cells were built around a mix of aging instrumentation, including TrigTek tracking filters, [...]
Spindle Run Out
Industry Automotive Applications Spindle Run Out Measurement Type Positioning Description Rotating targets frequently have an intermittent, uncertain or nonexistent ground path. This introduces unwanted noise, instability, drift and reduces accuracy of the measurement. MTI Instruments offers a unique “Push-Pull” capacitance measurement system that does not require a grounded target. It utilizes two probes, built into one body, that work together to complete the ground path. One probe pushes current into the brake rotor while the adjacent probe pulls the current out. The result is a “clean”, consistent electrical sensing path. As the [...]
CAPACITANCE SENSORS FACILITATE 3D IC CONSTRUCTION
[Application Note 70518] To boost device performance, today’s semiconductor and microelectronics manufacturers are building three-dimensional integrated circuits featuring vertically-stacked silicon wafers and dies. The rationale is simple. Exploiting the Z-axis avoids the power and footprint penalties associated with two-dimensional processes. Implementing the rationale, however, is not so simple. Going vertical requires coplanar surfaces to make contact with all pins, pads, and pillars. Problem Typically, manufacturers measure the angle and gap between two planes to determine coplanarity. Bonding tool actuators rely on these angle/gap measurements to adjust components and make sure all device pins and/or solder balls reside on the [...]
Application Note: Why Charge Amplifiers Remain Essential in Aerospace Test Systems
Introduction Many aerospace test programs rely on charge-output piezoelectric accelerometers, force sensors, and dynamic pressure transducers because of their wide frequency response, rugged construction, and ability to capture rapidly changing events. These sensors generate extremely small electrical charge signals—often measured in picocoulombs (pC)—that are susceptible to cable capacitance effects, electrical noise, leakage currents, and environmental influences that can compromise measurement accuracy. Charge amplifiers address these challenges by converting the sensor’s high-impedance charge output into a stable, low impedance voltage signal suitable for transmission, recording, and analysis. By making measurements largely independent of cable capacitance while maintaining low noise, stable [...]
CAMERA SHIELD MEASUREMENT
Equipment Setup Equipment Used DTS-25-04 laser head Rotary Stage PC with Digital Microtrak Basic Support software Setup Power is automatic mode. Filter is 100Hz Sample rate is 1000 samples sec The head was operated in diffuse mode (not specular/tilted) Validation of Setup The setup should be validated by performing a total runout scan on the rotary stage with no target present. The stage should be cleaned with Isopropyl alcohol and allowed to dry prior to the scan. This reduces any dust or dirt accumulation which will give a false reading of runout. A 360-degree runout of the rotary table, [...]
Application Note: Accessing Digital Engine Data for Multi-Platform Aircraft Balancing with MTI PBS Systems GalleryApplication Note: Accessing Digital Engine Data for Multi-Platform Aircraft Balancing with MTI PBS Systems
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Application Note: Accessing Digital Engine Data for Multi-Platform Aircraft Balancing with MTI PBS Systems
Introduction Modern aircraft engines are no longer dependent solely on discrete analog sensors for critical performance data. Increasingly, vibration amplitudes, phase information, and engine speed are transmitted digitally through aircraft data buses such as ARINC 429 and ARINC 664 Part 7 (AFDX). Yet in many MRO environments, balancing systems continue to rely on accelerometers and tachometer pickups—introducing additional setup time, cabling complexity, and potential variability in measurements. This disconnect between available digital data and traditional measurement approaches creates inefficiencies, particularly for facilities servicing multiple aircraft platforms. For organizations supporting a diverse fleet, the opportunity is clear: leverage the aircraft’s [...]
MONITOR ROLLER GAPS AND PARALLELISM
Easy Roller Gap Measurement Ensures Calendering Success Many roll-to-roll finishing processes typically use a calender, or series of hard pressure rollers, to deliver smooth, high-quality products of plastic, textile, or paper (Fig 1). Ensuring a consistent material thickness, however, depends on the ability to monitor, and maintain, a precise gap between rollers. This application note describes a quick and easy means for roller gap measurement. Problem Establishing a roller gap and checking for parallelism across roller width can be a slow and cumbersome procedure. Manual measurement requires multiple sized feeler gauges which can introduce errors. Misinterpreting feeler gauge drag, [...]