Abstract: A system and method of compensating for pressure variations in a flow controller entails the use of the compressibility of the gas being controlled to provide a more accurate measurement of the flow.

Abstract: A thermal mass flow controller or mass flow meter having a novel sensor housing that reduces heat conduction from the housing mounting plate or base to the sensor itself. The housing also greatly minimizes the thermal gradient that can result from the uneven application of heat to the housing base. This reduction is accomplished in part by the use of one or more thermal isolation slots to isolate the upper portion of the housing (which holds the sensor) from the lower portion of the housing. Heat transfer to the sensor housing is also minimized by raising the middle portion of the bottom of the housing so that thermal contact is made between the base and the housing only at the two ends of the housing.

Abstract: Systems and methods for liquid flow sensing and control for use with a variety of different types of liquid flow measurement and control systems. The liquid flow sensor system senses a flow signal indicative of the flow rate of the liquid flowing in a sensor conduit and analyzes the flow signal to determine, by detecting characteristic changes in the signal, whether a bubble is present in the sensor conduit. Where the system determines that a bubble is present, it may generate an alarm signal indicative of the presence of the bubble. A flow control system incorporating the flow sensor as a feedback source may respond to the detection of a bubble by temporarily freezing the flow control parameters until the bubble has exited the sensor conduit. The flow control system can implement procedures for clearing a bubble from the sensor conduit where the system detects that the bubble has become stuck.

Abstract: An improved flow measuring device, such as a mass flow meter or mass flow controller, providing a high turn-down ratio as compared to prior art devices. In accordance with various embodiments of the invention, a flow sensor includes a sensor flow path that includes one or more restrictions configured to provide the sensor flow path with a non-linear relationship between a pressure drop across the sensor flow path and the flow of fluid through the flow sensor conduit. Such a flow sensor preferably achieves a high turn-down ratio by way of a variable bypass ratio that is directly proportional to the sensor tube mass flow rate so that the turn-down ratio of the mass flow controller will be ideally proportional to the square of the turndown achievable by the flow sensor conduit fluid sensing portion alone. In some embodiments, the restriction can be employed as a part of a fluid seal having an orifice and disposed between a flow sensor portion of a flow meter and a bypass portion of the flow meter.

Abstract: Performance of mass flow controller may be vulnerable to pressure transients in a flow path to which the controller is coupled for the purpose of controlling the fluid flow. A system and method are provided for reducing or eliminate performance degradations, instabilities, and/or inaccuracies of a mass flow controller caused by changes in the pressure environment. In particular, a method and system are provided for compensating for pressure transients in the pressure environment of a flow path and mass flow controller.

Abstract: Systems and methods for digitally controlling sensors. In one embodiment, a digital controller for a capacitance diaphragm gauge is embedded in a digital signal processor (DSP). The controller receives digitized input from a sensor AFE via a variable gain module, a zero offset module and an analog-to-digital converter. The controller automatically calibrates the received input by adjusting the variable gain and zero offset modules. The controller also monitors and adjusts a heater assembly to maintain an appropriate temperature at the sensor. The controller utilizes a kernel module that allocates processing resources to the various tasks of a gauge controller module. The kernel module repetitively executes iterations of a loop, wherein in each iteration, all of a set of high priority tasks are performed and one of a set of lower priority tasks are performed. The controller module thereby provides sensor measurement output at precisely periodic intervals, while performing ancillary functions as well.

Abstract: Performance of mass flow controller may be vulnerable to pressure transients in a flow path to which the controller is coupled for the purpose of controlling the fluid flow. A system and method are provided for reducing or eliminate performance degradations, instabilities, and/or inaccuracies of a mass flow controller caused by changes in the pressure environment. In particular, a method and system are provided for compensating for pressure transients in the pressure environment of a flow path and mass flow controller.

Abstract: A fluid flow control system that includes a fluid inlet to receive a flow of process fluid and a plurality of fluid outlets. The plurality of fluid outlets include a first fluid outlet and at least one second fluid outlet. The first fluid outlet provides a first predetermined portion of the flow of process fluid, and the at least one second fluid outlet provides the remaining portion of the flow of process fluid. In one embodiment, the control system includes a pressure transducer, first and second multipliers, and first and second flow controllers. The first multiplier multiplies a pressure signal received from the pressure transducer by a first setpoint to control a first flow controller that provides the first predetermined portion of the flow of process fluid. The second multiplier multiplies the pressure signal by a second setpoint to control a second flow controller that provides the remaining portion.

Abstract: Systems and methods for flow verification and validation of mass flow controllers are disclosed. A mass flow controller may be commanded to a specified flow and flow measurement commenced. During an interval, gas is accumulated in a first volume and measurements taken within this volume. The various measurements taken during the interval may then be used to calculate the flow rate. The flow rate, in turn, may be used to determine the accuracy of the mass flow controller relative to a setpoint.

Abstract: Systems and methods for flow verification and validation of mass flow controllers are disclosed. A mass flow controller may be commanded to a specified flow and flow measurement commenced. Gas is accumulated in a first volume and while measurements are taken within this volume. Gas may then flow into a second volume while measurements are taken. The various measurements taken during the two intervals may then be used to calculate the flow rate. The flow rate, in turn, may be used to determine the accuracy of the mass flow controller relative to a setpoint. Additionally, these systems and methods may utilize only one volume to perform flow verification by flowing gas into this volume, taking measurements, and calculating the flow rate based only upon this set of measurements.

Abstract: Disclosed herein are systems and methods for attitude insensitive flow devices. The system can include a flow device having a processor and a computer readable medium accessible by the processor that stores a set of computer instructions executable by the processor. The computer instructions can include instructions executable to receive an orientation signal, receive a sensed flow signal, and determine a flow through the flow device based on the sensed flow signal and the orientation signal.

Abstract: A thermal mass flow meter associated with an inclination sensor that detects an angle of inclination of at least one portion of a thermal mass flow sensor relative to at least one reference axis. Based upon the detected angle of inclination, the output signal of the mass flow meter that is indicative of the mass flow rate of fluid through the sensor may be compensated to account for any inaccuracies relating to the orientation in which the mass flow meter is installed. Inaccuracies for which compensation may be provided include thermal siphoning effects and fluid buoyancy effects. By compensating for such inaccuracies, the mass flow meter may be used in any orientation, and/or may be used in non-inertial (e.g., accelerating) environments. The flow meter may be used as a stand alone device, or incorporated in a thermal mass flow controller.

Abstract: A variable capacitance measuring device can comprise any one or more features in various different embodiments allow a reliable, compact device to be achieved. A capacitor electrode, a gettering housing, and pinch-off connector may be aligned along a common axis may reduce width dimensions without a substantial increase in length. Temperature-induced variations may be reduced by selecting materials that have coefficients of thermal expansion relatively closer to one another. Substantially varying topologies for ceramic-metal interfaces may reduce the likelihood of external contaminants from reaching the evacuated portion of the device. A tube can be used between the capacitor portion and a gettering housing to isolate external forces and getter activation heat from the sensor. The same tube also reduces heat loss from a heated sensor and protects the electronics from overheating. Embodiments also include processes for using and forming the devices.

Abstract: A system and method for controlling a mass flow controller to have a constant control loop gain under a variety of different types of fluids and operating conditions, and for configuring the mass flow controller for operation with a fluid and/or operating conditions different from that used during a production of the mass flow controller. Further, the system and method includes providing control by reducing the effects of hysteresis in solenoid actuated devices by providing a non-operational signal to the solenoid actuated device.

Abstract: Systems and methods for controlling the temperature of a wafer are disclosed. These systems and methods may employ a back side wafer pressure control system (BSWPC) that includes subsystems and a controller operable in tandem to control the temperature of wafers in one or more process chambers. The subsystems may include mechanical components for controlling a flow of gas to the backside of a wafer while the controller may be utilized to control these mechanical components in order to control wafer temperature in a process chamber. Furthermore, embodiments of these systems and methods may also use a chiller in combination with the controller to provide both coarse and fine temperature control.

Abstract: A fluid flow control system that includes a fluid inlet to receive a flow of process fluid and a plurality of fluid outlets. The plurality of fluid outlets include a first fluid outlet and at least one second fluid outlet. The first fluid outlet provides a first predetermined portion of the flow of process fluid, and the at least one second fluid outlet provides the remaining portion of the flow of process fluid. In one embodiment, the control system includes a pressure transducer, first and second multipliers, and first and second flow controllers. The first multiplier multiplies a pressure signal received from the pressure transducer by a first setpoint to control a first flow controller that provides the first predetermined portion of the flow of process fluid. The second multiplier multiplies the pressure signal by a second setpoint to control a second flow controller that provides the remaining portion.

Abstract: Systems and methods for correcting measurements of fluid flow using device-specific information to compensate for differences between individual devices of the same design. In one embodiment, a method includes providing device-specific calibration data; sensing a fluid flow; computing a measured fluid flow based on the sensed fluid flow, and correcting the measured fluid flow based on the device-specific calibration data. More particularly, the fluid flow measurement is corrected using correction factors that compensate for the use of a gas that is different from the calibration gas (CF0 (1+aF+bF2+cF3)), for device variations in sensor sensitivity (1+??R), and for variations in the split flow of fluid through the flow meter (1???ADC(Sp/100)2). The sensor and split flow correction factors may be used independently of each other in some embodiments.

Abstract: An ultrasonic flow sensor that includes a conduit having a length, a first ultrasonic transducer disposed at a first position along the length of the conduit, a second ultrasonic transducer disposed at a second position along the length of the conduit, the second position being spaced apart from the first position, a first reflecting interface and a second reflecting interface. The first reflecting interface is in registration with the first ultrasonic transducer to receive first acoustic energy from the first ultrasonic transducer and to reflect the first acoustic energy in a direction generally along a length of the conduit and into a fluid within the conduit. The second reflecting interface is in registration with the second ultrasonic transducer to receive second acoustic energy from the second ultrasonic transducer and to reflect the second acoustic energy in a direction generally along the length of the conduit and into the fluid within the conduit.

Abstract: A method and apparatus for blending and supplying process materials. The method and apparatus are particularly applicable to the blending of ultra-high purity chemicals, the blending of abrasive slurries with other chemicals for the polishing of semiconductor wafers, and high-accuracy blending of chemicals.

Abstract: A method and apparatus for blending and supplying process materials. The method and apparatus are particularly applicable to the blending of ultra-high purity chemicals, the blending of abrasive slurries with other chemicals for the polishing of semiconductor wafers, and high-accuracy blending of chemicals. The apparatus may include a dispensing subsystem that supplies process materials to a mixing subsystem where they are blended with a static mixer. The method may include supplying process materials with a dispensing subsystem and blending the process materials in a static mixer.