Liquid crystal display (LCD) screens are omnipresent in our technologically saturated lives. Having largely displaced the older CRT screens, LCDs make up a large portion of the digital imaging we see all around us. They are present in everything from our ubiquitous smartphones and computer screens to digital billboards, wristwatches and vehicle and aircraft instrumentation. How do flat panel LCD screens work? One can often find videos and articles documenting eager teardowns of new devices, but few delve beyond the hardware and into the materials and design behind the screen itself. For this series of blog posts, we will be review some aspects of display technology , why they work, and how they are assembled. To illustrate my points, I’ve disassembled a legacy Sony Ericsson® S500i phone [...]
Figure 1: Unpowered Sony Ericsson S500i LCD screen at 200x magnification In our last blog post, I wrote about some of the physics and materials science principles that go into the design and manufacture of liquid-crystal display (LCD) screens. The eponymous liquid crystals (LCs) in such a display have to be quite small in order to create a seamless image; as I mentioned in the last entry, the subpixels (the red, green and blue elements comprising a pixel, visible in Figure 1) can be smaller than a red blood cell. Each of these subpixels needs its own control system that interacts with the data drivers along the periphery of the screen. These power and control circuit components [...]
Figure 1: Composite layered heater from patent US 9,224,626 B2 Alexander Glew, Ph.D., P.E. recently contributed to a new patent on an advanced thin-film electric heaters, layered composite heaters, for CVD semiconductor processing and related technologies titled “Composite substrate for layered heaters”. Watlow Electric, based in St. Louis, hired Glew Engineering and Dr. Glew to help develop this heater technology due to his experience in the Silicon Valley’s semiconductor industry. As a semiconductor equipment expert and materials engineering consultant, Dr. Glew’s familiarity with semiconductor manufacturing meant he understood both the limitations of common semiconductor chuck heating methods and the techniques that could be used to construct a better heater. In this post, we review how this composite heater capitalizes on semiconductor [...]
Equipment designers must accommodate thermal expansion (CTE)of dissimilar materials, especially when they are subject to large temperature changes. This problem is often called "CTE mismatch." In this blog, we give the fundamentals of thermal expansion calculations used in thermo-mechanical analysis. These calculations are simple but useful, and easy enough to perform by hand or with a spread sheet. For more complicated shapes, one must use computer modeling. As an example, we perform a finite element analysis (FEA) in a later blog http://glewengineering.com/thermal-expansion-in-a-glass-and-aluminum-window-part-2/, of a glass and aluminum window and frame to show where the stress is excessive. This points to the obvious need for a gasket to perform as a thermal interface material, in order to lessen [...]
Fig. 1 Tall Fire from Chemical We have written about pyrophoric materials in a number of Glew Engineering’s previous blogs on safety in semiconductor fabrication, but have yet to cover how to define it or its danger. At its simplest, a pyrophoric substance is any substance that spontaneously ignites in room temperature air. As one might imagine, spontaneous combustion on contact with the regular atmosphere we live in can be quite dangerous. Last year, Glew Engineering assisted a research lab in designing a safe gas distribution system for their plasma-enhanced chemical vapor deposition chamber. During the initial work, the building administrators and safety managers were concerned about the lab’s proposed use of silane and germane, two pyrophoric and toxic materials. To them, [...]
Thermal Mass Flow Controllers A mass flow controller (MFC) for each gas line in a semiconductor tool’s gas panel measures and regulates the mass flow of the gas in order to set the gas entering the process chamber to the values in the process recipe. While pressure regulation and temperature control are needed for sensitive chemical vapor deposition (CVD), plasma etching, or thin film processes, gas flow control can be just as important. Semiconductor process recipes involve precise ratios of gas phase chemical to assure the correct stoichiomtery and reaction rates. Due to the accuracy and precision required of the gas flow rate, mass flow controllers are often the most sensitive and expensive components installed in a gas [...]
An article on pressure transducers used in semiconductor fabs and semiconductor equipment.
Pressure gauges and pressure transducer use in semiconductor fabs.
Devices for regulating gas pressure in semiconductor processes.
Valve specification and design for high purity semiconductor equipment.
Mechanical engineering for high-purity processes in semiconductor fabs: gas distribution lines for transporting hazardous gases and materials.
Mechanical engineering design for high-purity processes in semiconductor fabs: process pumps, abatement and exhaust lines.
Mechanical engineering design for high-purity processes in semiconductor fabs: gas cabinets, liquid sources and valve manifold boxes.
Introduction to our blog series on the complexities of mechanical engineering design for high-purity gas panels in semiconductor fabrication.
A close look at how 2-D phosphorus is being used in 2-Dimensional drumhead resonators, and what this means for future electronic devices.
Semiconductor & Robotics Industries Prepare for 450mm Wafers.