Wafer drying

Funkhanel J, Schupke K. Wafer drying in wet processing the challenge of the future. Semiconductor International Oct 2004. 

K. Wolke, B. Eite, M. Schenki, S. Rummelin, R. Schild, Marangoni wafer drying avoids disadvantages. Solid State Technol. 39 (8) (1996) 87. 

Cmmbles are formed by grinding pellets to the desired sizes. Specialty feeds such as flakes can be made by mnning newly manufactured pellets through a press or through use of a double dmm dryer. The latter type of flakes begin as a slurry of feed ingredients and water. When the slurry is pressed between the hot rollers of the double dmm dryer, wafer thin sheets of dry feed are produced that are then broken into small pieces. The different colors observed in some tropical fish foods represent a mixture of flakes, each of which contains one or more different additives that impart color. 

Waferboard, a more recent wood constmction product, competes more with plywood than particle board. Waferboard and strand board are bonded with soHd, rather than Hquid, phenoHc resins. Both pulverized and spray-dried, rapid-curing resins have been successfully appHed. Wafers are dried, dusted with powdered resin and wax, and formed on a caul plate. A top caul plate is added and the wafers are bonded in a press at ca 180°C for 5—10 min. Physical properties such as flexural strength, modulus, and internal bond are similar to those of a plywood of equivalent thickness. 

The impurities on the surface are contained in the resulting water droplet or moisture film, and are collected in situ for further investigation by scanning the surface with an auxiliary water droplet (e.g., 50 pi). The VPD residue is allowed to dry in the center of the wafer and subjected to TXRF analysis. A schematic of a VPD reactor is shown in F ure 3. 

Vapor-phase decomposition and collection (Figs 4.16 to 4.18) is a standardized method of silicon wafer surface analysis [4.11]. The native oxide on wafer surfaces readily reacts with isothermally distilled HF vapor and forms small droplets on the hydrophobic wafer surface at room temperature [4.66]. These small droplets can be collected with a scanning droplet. The scanned, accumulated droplets finally contain all dissolved contamination in the scanning droplet. It must be dried on a concentrated spot (diameter approximately 150 pm) and measured against the blank droplet residue of the scanning solution [4.67-4.69]. VPD-TXRF has been carefully evaluated against standardized surface analytical methods. The user is advised to use reliable reference materials [4.70-4.72]. 

Figure 8. Example of microwave conductivity transient map PMC relaxation time map taken from a 20- m thin silicon wafer onto which 11 droplets of zeolith suspension were deposited and dried. Reduced lifetimes are clearly observed in the region of droplets. For color version please see color plates opposite this page.

Bovine growth hormone, a difficult protein for which to develop controlled release systems due to its propensity toward self-aggregation and inactivation, has successfully been incorporated into polyanhydride matrices (18). The growth hormone was colyophilized with sucrose, dry-mixed with finely powdered polyanhydride, and then compression molded into 1.4-cm-diaraeter wafers, 1 mm thick. As is shown in Fig. 15, release of bovine growth hormone was well controlled over a prolonged period of time. The assay for bovine... 

The catalyst for the in situ FTIR-transmission measurements was pressed into a self-supporting wafer (diameter 3 cm, weight 10 mg). The wafer was placed at the center of the quartz-made IR cell which was equipped with two NaCl windows. The NaCI window s were cooled with water flow, thus the catalyst could be heated to 1000 K in the cell. A thermocouple was set close to the sample wafer to detect the temperature of the catalyst. The cell was connected to a closed-gas-circulation system which was linked to a vacuum line. The gases used for adsorption and reaction experiments were O, (99.95%), 0, (isotope purity, 97.5%), H2 (99.999%), CH4 (99.99%) and CD4 (isotope purity, 99.9%). For the reaction, the gases were circulated by a circulation pump and the products w ere removed by using an appropriate cold trap (e.g. dry-ice ethanol trap). The IR measurements were carried out with a JASCO FT/IR-7000 sprectrometer. Most of the spectra were recorded w ith 4 cm resolution and 50 scans. 

Microfabrication of the silicon part of the device is done by processing a silicon wafer with LPCVD and other thin-film techniques, standard photohfhography, dry... 

A (100) oriented p-silicon wafer (Wacker Chemitronic) was cut into 5x5 mm pieces. These were cleaned in a UV/ozone dry stripper (Samco) for 15 min followed by a two minute rinse in doubly deionized water. The samples were dried in clean air for several minutes. A 10 pi amount of TEOS (purchased by Aldrich, electronic grade, as received) was dropped onto the dried surfaces. The film was allowed to dry in ambient air for 10 minutes and then immediately transferred into the vaccum-chamber of the TOF-SIMS spectrometer. 

Complex formation between Co and chelating agents was investigated by FT-IR spectroscopy after the second impregnation followed by drying. The dried sample was diluted with KBr powder and then formed into a self-supporting wafer. FT-IR measurements were carried out in a transmittance mode on an FTS6000 FT-IR spectrometer (Varian) with spectral resolution and accumulation time of 4 cm 1 and 1,024, respectively. 

Figure 13.2. Inorganic micro/nanoscale elements derived from wafers can be used to form solution suspensions for delivery to another substrate (e.g., plastic sheet) by casting processes (left frame), or they can be dry transfer printed in a way that preserves their lithographically defined spatial organizations (right frame).

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