Mask design

As in electrodeposition, proper mask design aimed at achieving as uniform a layout of circuit elements as possible will be one of the keys to the future success of electroless deposition in microelectronics, whether it is employed to deposit conductors (Cu) or thin barrier layers. 

The optimization techniques are performed on mask design or processing level and approach planarity problems from different directions. Some of them reduce the pre-CMP topography, others reduce density variations or nonuniformity dimensions with respect to the planarization length, and still... 

As shown in the previous section, localized porous-type anodization and selective etching of A1 can be used for the fabrication of complex microstructures composed from freestanding porous AI2O3. As an example, Fig. 16a and b demonstrates SEM and optical images of microstructured porous AI2O3 substrates, which are utilized for sensor applications (Fig. 16c, d). The lateral dimensions of freestanding ceramic substrates were controlled by the mask design and process conditions. The thickness was controlled by the current density and duration of anodization (2 min anodization... 

EMM can be applied to either Al films, typically deposited on SiCVSi substrates, or Al foils. The dimensions of metallic features are determined by the same rules the etch factor, the depth of porous-type anodization, the mask design, and process conditions. In addition to the fabrication of metallic microstructures, EMM can be used to produce microstructured ceramic substrates composed of porous AI2O3. For the fabrication of both types of 3D microstructures by localized porous-type anodization, the following technological problems have to be addressed the reliability of a mask material, the fidelity of the mask transfer, volumetric expansion of porous AI2O3 during anodization, and the effect of the mask design on the rate of porous-type anodization and on the completion of anodization of the entire thickness of Al without traces of Al islands. 

For optimal mask design problem the Nx N vertices of the grid graph Gi correspond to a NxiV array. The distance between grid cells and(z2, 2)inthe... 

Whatever the type, faceseals must not extend beyond the hairline, otherwise trapped hair will cause leaks, and all faceseals need a cross-sectional skin contact of about 10 mm to be effective (not easy to achieve at the temples). If the respirator incorporates an oronasal mask designed to seal to the skin, then this, too, needs to seal properly without compromising the main face-seal. In addition, the topography of the oronasal sealing area is complex, particularly around the nose, and good fits across the whole user population are difficult to achieve. Some typical face-seals are shown in Figure 2. 

The combination of phase masks and specially designed, highly sensitive photopolymers can be used to fabricate fast, three-dimensional topographies using laser ablation. The improvements of the phase mask, by incorporating the ablation behavior of the polymer into the mask design, and the application of photopolymers which decompose without contamination of the surface, allows a fast fabrication of microoptical elements. 

Testing a suit and gas mask designed to resist nerve agents. 

Fig. 19 Mask design for the portable PCR-CE system. The glass mlcrocharmels are indicated in black, the RTD and microfabricated electrodes are in green, and the heater (located on the back of the device) Is shown in red. The PCR chamber is loaded through reservoirs a and b. Reservoir c is the co-inject reservoir, d is the cathode, e is the waste, and/is the anode. Reproduced from [ill] with permission...

By design, the SCALPEL exposure tool employs a small (1 mm x 1 mm) electron optical field, which is consistent with the strutted mask design and step-and-scan writing strategy. Since the electron optical field is the same width as the pattern area between the mask struts, die exposure is accomplished by mechanically scanning the mask and wafer through the effective electron optical field. ... 

Fig. 2-1. Theodore A. Hoffman patented this respirator in 1866. It is representative of the already developing protective mask designs of the post-American Civil War era. Ironically, these masks were superior to the ad hoc emergency masks used by the Allies after the Germans began chemical warfare in World War I. Reprinted from US Patent No. 58,255 25 Sep 1866.

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