Subtractive manufacturing process

The process time depends on the complexity of the 3D microstructures therefore, it is commonly used for prototyping. An extensive review on stereolithography can be found in Reference 119. The latter method is a subtractive manufacturing process that uses a focused high-intensity laser beam to evaporate the material from the surface. Laser ablation is mostly used to fabricate microchannels in thermosetting polymers such as polyimide due to its physical properties. Microstructures of nanometer scale have been danonstrated, but the surface roughness and properties using laser... 

By its virtue, chemical mechanical planarization (CMP) is a subtractive manufacturing process that polishes off overburden material as exemplified in Figure 17.3. So, naturally, once finished, it will reveal all the feamres underneath, circuits and defects alike. Also, in the semiconductor process flow, CMP is usually the terminal downstream process that completes the definition of a device or circuit. As a consequence, not only does it generate defects of its own, but it can also modulate defects from upstream processes. Therefore, the post-CMP defect target is usually the most stringent along the entire process flow because at this stage, defects have the most direct impacts on yield and reliability. 

Custom molds and dies, as well as many other commercial products, are typically produced by subtractive processes such as drilling, turning, milling, and so on, which machine away a larger work piece to obtain the desired shape. Subtractive manufacturing processes do not typically require significant investment on an application-specific basis (beyond the... 

Solid Freeform Fabrication (SFF) technologies have in common the capability to build objects with comphcated 3D geometries, directly from Computer-Aided Design (CAD) files, without the necessity of tooling. SFF technologies also have in common the employment of an additive building process, in which a 3D object is built up by the repeated addition of layers of material. This is in contrast to more standard technologies which are characterized by the implementation of a subtractive fabrication process, e.g., CNC (Computer Numerical Control), where the 3D object is manufactured by calculated removal of material from a block of raw material. 

Subtractive technique The continuous removal of material from a larger original piece in the manufacturing process examples include stone working and wood carving. Synchronic Dealing with a moment in time, a single time period. 

This chapter presents an overview of performance plastic polymers in commercial planar and 3-dimensional circuit board products, and describes in detail one approach (two-shot molding) developed as an integrated 3-D circuit manufacturing technology. The distinctions between conventional planar (2-dimensional) circuitry, based on thermoset laminates and "subtractive etching processes, and the enhanced design flexibility afforded by expanded interconnection capacity in three axes are discussed. Specific examples of 3-dimensional interconnect protoypes and products are described and pictured. 

Subtractive methods processes involving material removal starting from a stock piece (Kalpakjian and Schmid 2009). The main disadvantage of these methods is high setup and manufacturing time and costs when complex shapes are required. 

The flexural pivot is free of the problems associated with the knife edge. However, it can act as a spring and therefore may add an extra force to the weighing process. This force may artificially subtract from an object s true mass and provide inaccurate readings. This effect may arise as a result of time or as temperature changes. Manufacturing design may decrease this effect, and it may also be... 

Microfabrication has emerged from microelectronics manufacturing and is using its proven processes and process sequences. Additionally, specific methods have been developed to fabricate mechanical, electrical, optical, or sensor structures, which are characteristics of microfabrication. In order to stay within the scope of this book, only top-down methods, that is, the manufacture of smaller structures with higher functionality from larger structures by the use of subtractive methods, will be discussed. Bottom-up methods, which create larger structures by ordered arrangement of small units (molecules, nanoparticles), are still in their infancy and mainly employed for biosensors. 

Similarly, the computer contains a program for determining the intensities of the characteristic peaks. Again, two processes are used (i) the peak intensities are obtained by fitting a Gaussian profile, to which the peaks closely approximate, or (ii) the peak is compared with a library standard peak, which has been acquired previously and stored. There is little to pick between the two processes (as with those for background subtraction), and the operator usually has no choice because the processes available have been selected by the manufacturer of the EDX spectrometer system. 

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