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Nanosensor Laboratory
Published in Vinod Kumar Khanna, Nanosensors, 2021
During dicing, the wafer saw, consisting of a blade embedded with diamond particles that rotates at a very high speed, passes through the wafer at boundaries between dies known as saw streets, established during wafer fabrication. The dicing machine is programmed to drive the saw blade through the saw streets at a defined spindle speed, saw rate, and depth, separating the wafer into individual dies. The blade must be carefully aligned with saw streets to avoid any chip loss at this stage, where the wafer has undergone all the processes.
The Economics of Semiconductor Scaling
Published in Lambrechts Wynand, Sinha Saurabh, Abdallah Jassem, Prinsloo Jaco, Extending Moore’s Law through Advanced Semiconductor Design and Processing Techniques, 2018
Lambrechts Wynand, Sinha Saurabh, Prinsloo Jaco, Abdallah Jassem
In all three examples given in Figure 2.9, the wafer sizes are (arbitrarily) 300 mm in diameter. Figures 2.9a, b and c have dies of sizes 10 × 10 mm, 20 × 20 mm and 40 × 40 mm, respectively. In all three examples, the gray dies are discarded dies, typically found around the edges of the wafer and not processed as full dies; therefore, these dies are not included in the yield criteria. The black dies in these examples are dies that have passed optical and electrical inspection and the white dies have failed optical or electrical inspection. The yield equation used in this example is simplified and only determines the true yield based on the total number of fully processed dies and the number of dies that passed optical and electrical inspection, such that
Wafer Cleaning: Present and Future
Published in R. P. Donovan, Particle Control for Semiconductor Manufacturing, 2018
The purpose of a wafer-cleaning step is to remove surface particles as well as organic and inorganic contaminants, and to prepare a “clean” surface prior to specific process steps. To evaluate a wafer-cleaning technique, one must realize that a wafer-cleaning process is actually a chemical process designed to achieve a desired electrical result. Specific questions must be asked regarding the desired state of a wafer surface: What is the condition of the surface immediately prior to the cleaning treatment? Is there a native or chemical oxide layer that must be removed? What types of contaminants and particles appear on the surface? When do these contaminants appear? How do the types and quantities of surface impurities vary as a function of time?Is the wafer surface relatively flat, or are there many three-dimensional structures such as contact holes, vias, and trenches? What chemical treatments must be applied to the sides or bottom of these topographical structures?What is the required condition of the surface following the chemical treatment? Is a thin native or chemical oxide on the silicon surface desired? What level of particulate and molecular contaminants must be achieved? Is there a safe window of variability? To what degree must the surface, including the inner surfaces of three-dimensional structures, be dry?
Spatially weighted graph theory-based approach for monitoring faults in 3D topographic surfaces
Published in International Journal of Production Research, 2021
Mejdal A. Alqahtani, Myong K. Jeong, Elsayed A. Elsayed
Semiconductor wafers are commonly used for the fabrication of electronic chips such as diodes, transistors, capacitors, among others. The use of semiconductor wafers has many benefits in terms of its low cost, small weight, high processing speed, easy replacement, and low power consumption (Bao, Wang, and Jin 2014). There are various faults that might be observed during the manufacture of semiconductor wafers, which may result in lower functionality of the fabricated chips (Rao et al. 2015b). In particular, pits and ridge faults may observe on the surface topography of wafers because of chemical aging and uneven temperatures, respectively, whereas scratch faults may observe due to the material handling and shipping (Jeong, Kim, and Jeong 2008). Such faults are important indicators that should be addressed for accurate analyses of process changes. Figure 11 presents examples of the surface topography of non-smooth and smooth copper wafers measured using a laser interferometer (Rao et al. 2015a). Note that the non-smooth copper wafer is associated with different faults such as pits, ridges, and scratches.
Effects of substrates on the performance of optoelectronic devices: A review
Published in Cogent Engineering, 2020
Joseph Asare, Benjamin Agyei-Tuffour, Evangeline A. Amonoo, David Dodoo-Arhin, Emmanuel Nyankson, Bismark Mensah, Oluwaseun O. Oyewole, Abu Yaya, Boateng Onwona-Agyeman
A substrate mostly refers to a slice of semiconducting material like silicon or metal oxide in computing and electronics. (Duan et al., 2003; Rogers et al., 2009) Substrates serve as the foundation for the fabrication of components such as integrated circuits and transistors. Materials used for substrates are cut to form thin discs, sometimes called wafers, on which other electronic components are constructed. (Isa et al., 2009) Vacuum vapor deposition methods used mostly for substrate fabrication and deposition makes them light, flexible and non-oxidizing in air. (Jean et al., 2016; Montanino et al., 2015) Depending on the industry involved, the substrate material could differ, so the various types of substrates used based on the device configuration or fabrication parameters could be rigid or flexible depending on the intended purpose. (Mortimer et al., 2006; Rogers et al., 2009; Zardetto et al., 2011)
Minimising total completion time on single-machine scheduling with new integrated maintenance activities
Published in International Journal of Production Research, 2019
Tsui-Ping Chung, Zhen Xue, Tong Wu, Stephen C. Shih
A wafer, also referred to as a slice or substrate, is a thin slice of semiconductor material. Prior to the commencement of each manufacturing procedure, the wafers are required to undergo necessary cleaning operations to prevent them from being contaminated. To ensure that the wafers are kept tightly covered to avoid being in contact with contaminated surfaces, most of the wafer cleaning operations are carried out in a controlled cleanroom environment. Essentially, the process of wafer cleaning is to clean up and further remove contaminants (including particle, organic, and metal-ions) from the surface of wafers. Using a cleaning agent as the main material of wafer cleaning, contaminants are dissolved and removed from the wafer surfaces. It must be meticulously operated when applying such cleaning agents. In the event that the level of contamination has gone overboard, the cleaning agent may well be detrimental to the wafer surface. Thus, performing timely maintenance activities to change the cleaning agents is crucial.