Why Disc Geometry Matters In Wafer Production
This is the first of three articles in Semiconductor Wafer Measurement for Increased Profitability. The second article examines the cost of failing to inspect semiconductor wafers. The third article describes the benefits of using semi-automated, fully-automated, and manual systems for wafer metrology and inspection. Semiconductor wafers are cut from cylindrical silicon crystals, or ingots. The flatness of these disc-shaped wafers is controlled to tight tolerances to ensure that the entire wafer surface is suitable for integrated circuit (IC) production. If disc geometry is out-of-spec after cutting, it may be possible to reprocess the wafer. Cutting is only the first [...]
Advantages of Measuring Semiconductor Thin Film Thickness with Capacitance
Thin Film Thickness Measurement Using Capacitance in the Semiconductor Industry In the semiconductor industry, the precise measurement of thin film thickness is crucial for ensuring the quality and functionality of wafer coatings. Thin films are deposited onto silicon and other wafer materials one atomic layer at a time, and the thickness of these coatings significantly impacts the wafer’s electrical, optical, and mechanical properties. Thin film thickness measurement is particularly important for semiconductor wafers, which may have either conductive metallic films or non-conductive metal oxide films deposited onto them. Common deposition methods include chemical vapor deposition (CVD) and physical vapor [...]
Why Demand for SiC Wafers is Soaring and Durable
Silicon carbide (SiC) wafers are in high demand, particularly in high-temperature applications. Silicon carbide (SiC), a semiconductor material made of both silicon and carbon, can withstand extreme temperatures of up to 2700°C. Often referred to as carborundum, SiC’s unique properties also make it a key material in non-electronic applications such as bulletproof vests, extrusion dies, sandpaper, and high-performance disc brakes. In the electronics industry, SiC wafers are crucial for devices operating under high temperatures, high voltages, or both. For example, they are used in electric vehicle (EV) power electronics, 5G communication systems, and LED technology, making SiC a material [...]
Wafer Stress Analysis Using the 300iSA
Wafer Stress Analysis Using MTI Instruments Proforma 300iSA Wafer processing involves several stages that can lead to mechanical changes in the wafer structure. These changes, or stresses, may result in deformities, making the wafer either unusable or only marginally usable. To evaluate these stresses and determine the wafer's quality, wafer stress measurement is essential. The Proforma 300iSA wafer characterization tool offers a powerful solution for wafer stress analysis. It allows for the analysis of a wafer both before and after processing. By comparing these two states, the Proforma 300iSA effectively evaluates the wafer's stress levels and mechanical alterations, providing [...]
CMP and Capacitance-Based Semiconductor Wafer Measurement
Chemical mechanical polishing (CMP) uses chemical oxidation and mechanical abrasion to selectively remove material from semiconductor wafers in order to achieve very high levels of planarity. The planarity, or flatness, of these wafers is important for optical lithography, a microfabrication technique that produces integrated circuits (ICs) by transferring a geometric pattern from a photomask to a light-sensitive chemical photoresist. Also known as photolithography or UV lithography, optical lithography can produce a geometric pattern on a thin film or directly onto the substrate. Semiconductor Wafer Measurements: Flatness and Shape During optical lithography, variations in wafer flatness must be smaller than [...]
MEMS and Capacitance-Based Semiconductor Wafer Measurement
MEMS Technology and Capacitance-Based Wafer Measurement Micro-electrical-mechanical systems (MEMS) are tiny devices that house electrical and mechanical components on a single silicon chip or integrated circuit (IC). They integrate mechanical structures with electronics that are normally fabricated with complementary metal-oxide-semiconductor (CMOS) technologies. In addition to miniaturization, the benefits of MEMS include expanded functionalities at lower cost and with improved performance and reliability. With MEMS devices, critical physical dimensions range from smaller than one micron (µ) to larger than several millimeters (mm). In complex systems, multiple moving elements may be controlled by integrated electronics. Examples of the mechanical components in [...]
Wafer Backgrinding and Semiconductor Thickness Measurements
Wafer Backgrinding and Thickness Measurements in Semiconductor Manufacturing Wafer backgrinding, also known as wafer thinning or wafer lapping, is a critical step in semiconductor packaging. This process, which involves grinding the backside of a semiconductor wafer, reduces its thickness to enable the stacking of integrated circuits (ICs) and support high-density packaging. The thickness of the wafer plays a crucial role in determining the overall size of the package, an important factor as modern electronics such as smartphones, laptops, and other devices continue to get thinner and more compact. In applications like MEMS (Micro-Electro-Mechanical Systems), the backgrinding process also affects [...]
Transducer Selection for High Resolution Applications
High resolution applications do not always require an interferometer. If you want to make accurate measurements in the micron to picometer range, then an MTI Digital Accumeasure D100 HD or D200 system may be what you need. Laser interferometers can sell for more than $15,000 and be difficult to setup. For example, you may have to buy additional optics to guarantee a good return signal since the laser beam must reflect off a mirror surface or precision retro reflector in order for the beam to re-enter the interferometer’s optics at less than a degree of reflection angle. The downsides [...]
High Resolution Semiconductor Wafer Measurements at Lower Costs
MTI's Proforma technology characterizes semiconductor wafers in terms of bow and warp, thickness, total thickness variation (TTV) and center thickness. Until recently, semiconductor wafer measurements at resolutions less than 100 µm were cost-prohibitive. Moreover, only expensive devices such as interferometers were capable of these measurements. Today, the semiconductor industry can use capacitance gauges instead of laser interferometers to achieve high resolution at fraction of the cost. Much like affordable CCD cameras transformed and expanded the market for video, cost-effective capacitance is disrupting the semiconductor wafer measurement market and creating new opportunities for quality testing and validation. The [...]
Capacitance Sensing for Non-Contact Thickness Measurements of Insulating Materials
Capacitance sensing can be used to make non-contact thickness measurements for most insulating materials. Capacitance sensors are known for their ability to precisely measure the thickness and position of conductive targets, but what’s less known is that these sensors can also measure the thickness of non-conductive materials. Examples include glass, sapphire, and plastics, as well as semi-insulating semiconductor materials such as GaAs and silicon nitride. Analog vs. Digital Technologies MTI Instruments, a global supplier of precision measurement technologies, takes the guesswork out of what used to be a complex measurement for non-conductive materials. MTI's Digital Accumeasure system features a [...]






