Abstract: A method for removing chemisorbed halogens from the surface of a silicon wafer after a plasm etching process is described. The removal takes place before the wafer is unloaded from the etching chamber in order to avoid exposure to atmospheric moisture. Exposure to moisture would cause the discharge of the chemisorbed halogen into the ambient causing corrosion of metal surfaces, particulate formation which reduces product yield, and unsafe halogen levels near the etching tool. The method is particularly useful during silicon etching with HBr where considerable amounts of bromine are chemisorbed onto wafer surfaces. After the etching process is complete, and without breaking vacuum, a carrier gas containing water vapor is flowed over the wafer for a brief time period. The chemisorbed bromine reacts with the water vapor and is converted to HBr which is then purged from the chamber.

Abstract: A method for preventing corrosion in a load-lock chamber used in a cluster-type wafer processing system by utilizing an additional degas chamber and by the execution of an additional degas operation is provided. In the method, a degas chamber which is equipped with a purge gas inlet and a purge gas outlet directed at a wafer surface positioned in the degas chamber is used. The wafer is degassed by a purge gas of N.sub.2, O.sub.2 or any other suitable gas prior to being transferred back to a load-lock chamber. A suitable purge gas flow rate between about 100 sccm and about 5,000 sccm is used to effectively purge away undesirable, residual process gas from the surface of a wafer. In an alternate embodiment, the purge gas of N.sub.2 or O.sub.2 may be preheated to at least 30.degree. C. to improve the efficiency of purging. In another alternate embodiment, the wafer itself may be heated in the degas chamber to a temperature of between about 100.degree. C. and about 250.degree. C.

Abstract: The invention relates to a technique called "Internal Linear Feedback (ILF)" for the stabilization of high-order sigma-delta modulators. The ILF technique involves an overload detector and a selector. Once "overloaded" is detected by the overload detector, the selector is activated to make the modulator entering the ILF mode, in which additional internal linear feedback paths are employed to stabilize the modulator. Otherwise, the modulator operates in normal mode as a general high-order modulator.

Abstract: The invention relates to a high performance and absolute stable 4th-order sigma-delta modulator with leapfrog topology which contains the following key components: (a) four integrators for integrating the difference signal between the input and reconstruct signal; (b) three add/subtract adders for adding or subtracting analog signal; (c) three loop coefficient control members for controlling the performance and stability of the modulator, (d) an analog-to-digital converter (A/D converter) for quantizing the output signals of the fourth integrator to digital codes, and (e) a digital-to-analog converter (D/A converter) for converting the digital codes to analog signals.