Abstract: A via opening (24) is formed within a semiconductor structure (10) in order to allow for the insertion of a contact to establish multi-level interconnects in an integrated circuit. The via opening (24) extends to a conductive layer (16) within the semiconductor structure (10). During the formation of the via opening (24), a residual layer (26) is created within the via opening (24) and on the exposed surface of the conductive layer (16). A dry plasma material is introduced at the semiconductor structure (10) to remove the residual layer (26) from the via opening (24) and the exposed surface of the conductive layer (16). After removal of the residual layer (26), a conductive material for establishing the contact for connection to the conductive layer (16) is inserted within the via opening (24).

Abstract: A combined transducer that measures force or displacement and temperature utilizes a pair of vibrating tines to provide a simultaneous output representative of temperature and force or displacement whereby the sum or average of the vibrating frequencies of the two tines is representative of temperature and the difference is representative of force or displacement.

Abstract: Apparatus and method for counting frequency of a signal with improved resolution. Frequency counters (10, 60, and 100) accumulate clock cycles from a reference oscillator (20) during a sample interval. In the simplest form of the frequency counter, the reference clock signal is inverted and both the noninverted and inverted clock cycles are accumulated in separate counters (40 and 44). The accumulated counts are totaled in a summing circuit (48) and divided by two to determine their average, thereby doubling the resolution of the frequency counter. A more complex embodiment of the invention corrects a raw count of cycles of an input signal (12) that are accumulated during an extended sample interval defined by successive rising edges of a sample signal (114).

Abstract: A device and method for measuring the frequency of an input signal by measuring the number of cycles of the input signal that occur in a sample interval between successive sampling times t.sub.n. An integer counter determines an estimated integer number of input signal cycles, and fraction counters determine fractional counts by counting cycles of a clock signal during time intervals between a first measurement time before the sampling time and a second measurement time after the sampling time. A correction circuit refines the fractional counts by determining the phase relationships between the clock and input signals at each measurement time. The correction circuit includes a constant current source, a capacitor, a first switch connected between the constant current source and a reference potential, a second switch connected between the constant current source and the capacitor, and a control circuit for the switches.

Abstract: An apparatus and method for counting the number of cycles of a sensor signal and of a reference signal that occur during respective time intervals associated with a sampling interval defined by a sample signal. Sensor and reference gate signals are produced and respectively define sensor and reference intervals. The sensor interval begins and ends synchronously with respect to the sensor signal, and the reference interval begins and ends synchronously with respect to the reference signal. The sensor, reference and sampling intervals are approximately coextensive with one another. Cycles of the sensor and reference signals are counted during the sensor and reference intervals, respectively. The process may be repeated for a plurality of successive sampling intervals.

Abstract: An accelerometer has two proof masses each constrained from movement by a beam resonant force transducer. The proof mass-force transducer systems are mounted with the sensitive axes of the proof masses aligned and the force transducers arranged so that their resonant frequencies f.sub.1 and f.sub.2 vary oppositely with a change in acceleration. The acceleration is determined in accordance with the relationa=A.sub.1 f.sub.1 -A.sub.2 f.sub.3 +A.sub.0ora=A.sub.1 f.sub.1.sup.2 -A.sub.2 f.sub.2.sup.2 +A.sub.0where a is the acceleration and A.sub.1, A.sub.2 and A.sub.0 are calibration coefficients.

Abstract: Recognizing and counting geometrically distant objects, such as objects of a particular morphological type (e.g., reticulated red blood cells), located in a field of objects of varying types is disclosed. Coherent light is directed toward a monolayer of objects of various types. The light scattered by the objects is collected by a collecting lens and forms a composite Fourier spectrum at the focal plane of the lens. The Fourier spectrum is selectively analyzed on the basis that each object creates a unique portion of the composite Fourier spectrum, and that a family of objects that are geometrically similar have additive spectrums, when their population is large, randomly located, and nonoverlapping. The analysis is performed by making intensity measurements at radial points in the Fourier plane, weighting the measurements, and summing the result. The radial points and weighting factors are determined using regression techniques.