Abstract: A circuit is provided that provides for the same power characteristics to an assembly of electrical resistive elements wired in parallel as to the assembly as wired in series. An input power source provides electrical resistive power to a plurality of load elements, wherein the plurality of load elements are connected in parallel to each other. A plurality of power splitters divide the power source into separate and equal power subsources such that there is one power splitter and one power subsource for each load element, wherein the power provided to each of the plurality of load elements is equal to the power of the electrical power source. Redundancy and fault tolerance is provided to the circuitry by permitting remaining load elements to continue to operate should one or more load elements fail.

Abstract: Heating element assemblies, heating furnaces incorporating heating element assemblies, methods to form heating element assemblies, methods to form heating furnaces and methods to reduce a magnetic field in a bifilar coil are disclosed. The heating element assembly includes two components, each component formed from heating element wire. The two components are spatially positioned and electrically arranged, relative to each other, so that an electrical current applied to the heating element assembly simultaneously travels through the two components in opposite directions.

Abstract: A method for monitoring the condition of a heating element involving installing the heating element in a location and setting the initial composition Ci of the material as a reference baseline at an initial time Ti corresponding to said installation of the heating element. Data is then collected reflecting the subsequent composition Cs of the heating element material after a subsequent time Ts at the installed location and any change in the material composition of the heating element between Ti and Ts is monitored. An alarm is sent when the change reaches a threshold value indicating a possible failure condition. According to one embodiment, an impedance monitor is provided that calculates and compares impedance at the required levels of accuracy to determine changes in material composition. The impedance monitor, or portions thereof can be embedded within a microcontroller for increased portability and functionality.

Abstract: A method for monitoring the condition of an electric current-carrying heating element involving installing the heating element in a location and setting the initial composition Ci of the material as a reference baseline at an initial time Ti corresponding to said installation of the heating element. Data is then collected reflecting the subsequent composition Cs of the heating element material after a subsequent time Ts at the installed location and any change in the material composition of the heating element between Ti and Ts is monitored. An alarm is sent when the change reaches a threshold value indicating a possible failure condition. According to one embodiment, an impedance monitor is provided that calculates and compares impedance at the required levels of accuracy to determine changes in material composition. The impedance monitor, or portions thereof may be embedded within a microcontroller for increased portability and functionality.

Abstract: A circuit is provided that provides for the same power characteristics to an assembly of electrical resistive elements wired in parallel as to the assembly as wired in series. An input power source provides electrical resistive power to a plurality of load elements, wherein the plurality of load elements are connected in parallel to each other. A plurality of power splitters divide the power source into separate and equal power subsources such that there is one power splitter and one power subsource for each load element, wherein the power provided to each of the plurality of load elements is equal to the power of the electrical power source. Redundancy and fault tolerance is provided to the circuitry by permitting remaining load elements to continue to operate should one or more load elements fail.

Abstract: A method for monitoring the condition of a heating element involving installing the heating element in a location and setting the initial composition Ci of the material as a reference baseline at an initial time Ti corresponding to said installation of the heating element. Data is then collected reflecting the subsequent composition Cs of the heating element material after a subsequent time Ts at the installed location and any change in the material composition of the heating element between Ti and Ts is monitored. An alarm is sent when the change reaches a threshold value indicating a possible failure condition. According to one embodiment, an impedance monitor is provided that calculates and compares impedance at the required levels of accuracy to determine changes in material composition. The impedance monitor, or portions thereof can be embedded within a microcontroller for increased portability and functionality.

Abstract: A method for monitoring the condition of an electric current-carrying heating element involving installing the heating element in a location and setting the initial composition Ci of the material as a reference baseline at an initial time Ti corresponding to said installation of the heating element. Data is then collected reflecting the subsequent composition Cs of the heating element material after a subsequent time Ts at the installed location and any change in the material composition of the heating element between Ti and Ts is monitored. An alarm is sent when the change reaches a threshold value indicating a possible failure condition. According to one embodiment, an impedance monitor is provided that calculates and compares impedance at the required levels of accuracy to determine changes in material composition. The impedance monitor, or portions thereof may be embedded within a microcontroller for increased portability and functionality.

Abstract: The present invention is an apparatus for calibrating a temperature feedback value in a water processing chamber to automatically compensate for variations in infrared emissions from a heated semiconductor wafer due to variations in composition and coatings from wafer to wafer. A calibration wafer with an imbedded thermocouple is used to generate a table relating actual wafer temperatures to power supplied to the heating chamber and infrared emissions detected by a pyrometer. A sample wafer of a batch to be processed is subsequently placed in the chamber at a known power level, and any difference between the detected infrared emission value and the value in the table is used to adjust the entire table according to a first predetermined formula or table. Before each wafer is processed, a known source of infrared light is reflected off the wafer and detected. The reflected light value is compared to a reflection measurement for the sample wafer.

Abstract: The present invention is a method and apparatus for calibrating a temperature feedback value in a wafer processing chamber to automatically compensate for variations in infrared emissions from a heated semiconductor wafer due to variations in composition and coatings from wafer to wafer. A calibration wafer with an imbedded thermocouple is used to generate a table relating actual wafer temperatures to power supplied to the heating chamber and infrared emissions detected by a pyrometer. A sample wafer of a batch to be processed is subsequently placed in the chamber at a known power level, and any difference between the detected infrared emission value and the value in the table is used to adjust the entire table according to a first predetermined formula or table. Before each wafer is processed, a known source of infrared light is reflected off the wafer and detected. The reflected light value is compared to a reflection measurement for the sample wafer.

Abstract: A low pressure control system for chemical vapor deposition (CVD) apparatus, including a vacuum pressure chamber and an exhaust pump, is provided by a vacuum pump DC motor which is supplied power from a DC motor speed controller coupled to a DC control input signal from a pulsewidth modulation DC converter. The converter receives a single pulsewidth modulated pulse train having its percentage of modulation controlled in accordance with a DC to pulsewidth modulation controller which operates in accordance with the difference between a pair of DC input signals corresponding to the actual pressure inside the vacuum pressure chamber and a desired or set point pressure respectively. The vacuum pump motor speed and accordingly the exhaust pump is controlled with a high degree of precision, thereby providing improved coating uniformity of semiconductor wafers being fabricated by the CVD apparatus.