Push-Pull Capacitance Sensor Measures Ungrounded Targets
Push-Pull Capacitance Sensor Measures Ungrounded Targets Solar, Semiconductor Measurement of Ungrounded Targets Thickness, Metrology Description [Application Note 50318] Today’s semiconductor and solar industries drive the demand for thinner wafers to conserve silicon and fulfill new IC applications. To meet this demand, wafer fabricators seek greater dimensional control of their silicon products. Non-contacting capacitance sensors offer the precision, accuracy, and speed needed to measure flatness, thickness variation, and other critical dimensions. Typically, the standard capacitance sensor acts as one plate of a classical two-plate capacitive gap measurement scenario. The grounded target [...]
Wafer Measurement – Ungrounded
Wafer Measurement - Ungrounded Semiconductor Wafer Measurement - Ungrounded Metrology Description MTI Instruments Inc. has developed a thickness measurement device that eliminates the effect of varying target conductivity. Called the Push-Pull probe, it’s a unique version of the AccumeasureTM amplifier series. This special design provides accurate surface information for wafer bow and warp. Bow is the deviation of the center point of the median surface of a free, un-clamped wafer from the median surface to the reference plane. Where, the reference plane is defined by three corners of equilateral triangle. This [...]
Wafer Thickness, Bow, Warp And TTV
Semiconductor Wafer Thickness, Bow, Warp And Ttv Surface Description Thickness Measurement 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). Figure above shows a wafer placed between two non-contact measurement probes. By monitoring changes between the upper probe face [...]
Tape Cartridge Movement
Tape Cartridge Movement Semiconductor Tape Cartridge Movement Positioning Description Researchers are presently working on drives with track widths in the 5 to 1 micron region. For these small widths, tape wander, properly called Lateral Tape Movement (LTM), must be less than 1 micron. This is because the track following head always lags the moving target and produces a position error signal. If the position error signal gets to be larger than about 1/10 the track width, the track cannot be read. However, it follows that the smaller the LTM, the [...]
Wafer QA/QC After Slicing And Polishing
Wafer QA/QC After Slicing And Polishing Semiconductor Wafer Qa/Qc After Slicing And Polishing Surface Description Introduction:When wafers are sliced up with wire saws, they are measured to make sure they are within the specified thickness, with minimal bow, warp, and TTV. After initial measurement, they are sorted and sent for polishing. Since polishing removes material and smoothes out the rough surfaces they need to be measured again to ensure they meet thickness guidelines and quality standards. Solution:MTI Instruments manufactures multiple systems to perform thickness measurements. From semi automated Proforma 300SA to manual [...]
Wire Bonding
Wire Bonding Semiconductor Wire Bonding Level Description Introduction What is Wire Bonding? Wire bonding is a critical semiconductor manufacturing process that creates electrical connections between integrated circuits (ICs) and their packaging substrates. This wire bonding technique uses ultra-thin bond wires, typically made of gold or aluminum, to establish reliable electrical pathways in microelectronics applications. Understanding Wire Bond Fundamentals A typical wire bond consists of bonded wire connecting a die pad to a substrate pad on a PC board. The bond wire diameter varies between 18 and 50 microns, with 25 microns [...]
GaAs Substrate Thickness Measurement
Semiconductor Gaas Substrate Thickness Measurement 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 [...]
Photolithography Using Capacitance Sensors
Photolithography Using Capacitance Sensors Semiconductor Photolithography Using Capacitance Sensors Positioning Description When it comes to photolithography, how accurate are our sensors? Accurate enough to measure this: ​   Photo by D. Carr and H. Craighead, Cornell The world's smallest guitar is 10 micrometers long -- about the size of a single cell -- with six strings each about 50 nanometers, or 100 atoms, wide. Made by Cornell University researchers from crystalline silicon, it demonstrates a new technology for a new generation of electromechanical devices. Even the world’s smallest guitar’s 2 micron [...]
Hard Drive Position
Semiconductor Hard Drive Position Positioning Description
LED Substrate Thickness
LED Substrate Thickness Semiconductor Led Substrate Thickness Thickness Description Remember that old acronym, GIGO?  Garbage in garbage out, it can apply to raw materials as well as programming. Sapphire wafers need to be of a certain quality to ensure maximum yield. Excessive TTV, Bow, and Warp lead to premature LED failure. LED manufacturers need to inspect incoming wafers. Wafer producers also need to check and control TTV, Bow and Warp. The market for sapphire wafers, driven by the growth in LED manufacturing, is booming. While the price has come down [...]