Shields

About: Shields is a research topic. Over the lifetime, 1456 publications have been published within this topic receiving 10896 citations.

Particulate reduction using temperature-controlled chamber shield

Abstract: Particle flaking is reduced in a semiconductor wafer processing apparatus by installing a chamber shield assembly in the chamber of the apparatus. The shield assembly includes a plurality of nested shields that are supported out of contact with each other and suspended such that, during thermal expansion and contraction, gaps are maintained that are sufficient to avoid arcing. Alignment structure on the shields and on the chamber walls force the shields to align concentrically and maintain the gaps. The shields are made of aluminum or another thermally conductive material and have cross-sectional areas large enough to provide high thermal conductivity throughout the shields. Mounting flanges and other mounting surfaces are provided on the shields that form intimate thermal contact with sufficient contacting area to insure high thermal conductivity from the shields to the temperature controlled walls of the chamber. Radiant lamps of an array are spaced around the chamber and extend vertically to expose multiple shields across large areas to heat for pre-heating bake-out of the shields and to eliminate thermal shock upon processing the first wafer of a run.

Geometrical aspects of magnetic shielding at extremely low frequencies

Abstract: The magnetic shielding effectiveness for closed and open shield structures is studied at extremely low frequencies. Analytical solutions are used for simple geometries, while more complex structures are evaluated using a finite-element method. Both highly conductive and ferromagnetic materials are studied, and their different shielding behavior is shown. Ferromagnetic shields give good results for small and closed shields and they also give a large field attenuation at close range to the source for open shield geometries. Highly conductive materials, on the other hand, are found to be suitable for large shield sizes. The attenuation is, however, reduced in the close vicinity of the source. Comparisons of numerical results with analytical calculations and measurements confirmed the high accuracy of the finite-element model. >

Principles of quasistatic magnetic shielding with cylindrical and spherical shields

Abstract: The basic principles that underlie materials-based quasistatic magnetic shielding are described. Shielding mechanisms are identified and shown in specific examples that involve long cylindrical and spherical shield geometries. Analytic results are given both for shields that enclose the shielded region and for shields that enclose the source. The two configurations are reciprocal in the sense that identical shields have identical shielding factors for a uniform externally applied field and for a dipole source within the shield. Flux shunting and induced current shielding mechanisms are each described quantitatively and qualitatively in shielding situations where only one mechanism is involved. Situations where the mechanisms are simultaneously involved are then analyzed, and the relevances of the descriptions that involve only one mechanism are identified as regimes within the general descriptions.

Method to make a perpendicular magnetic recording head with a side write shield

Abstract: A perpendicular magnetic recording (PMR) head is fabricated with a self-aligned pole tip shielded laterally by a separated pair of side shields and shielded from above by an upper shield. The side shields are formed from a shield layer by a RIE process characterized by a mask and gases producing a variety of etch rates. The differential in etch rates maintains the opening dimension within the mask and allows the formation of a wedge-shaped trench within the shield layer that then separates the layer into two shields. The pole tip is then plated within the trench and an upper shield is formed above the side shields and pole.