A ring oscillator for detecting a characteristic degradation of MOSFETs is required to be highly sensitive to NBTI degradation or PBTI degradation. A semiconductor device comprises a ring oscillator and a delay detecting circuit which detects a delay through gate circuits based on the oscillation frequency of the ring oscillator. The ring oscillator comprises an input terminal to which an oscillation control signal is input, an output terminal which outputs an oscillation signal, an oscillation control gate circuit having a first input terminal which is coupled to the input terminal and a second input terminal to which a terminal different from the input terminal is coupled, NAND circuits, and NOR circuits. The NAND and NOR circuits are cascade coupled alternately, plural inputs of the NAND circuits and of the NOR circuits are coupled together, and drive power of the NAND circuits differs from drive power of the NOR circuits.

Apparatuses including test segment circuits and methods for testing the same are disclosed. An example apparatus includes a plurality of segment lines configured to form a ring around a die and a plurality of test segment circuits, each test segment circuit coupled to at least two segment lines of the plurality of segment lines. Each test segment circuit is coupled to a portion of a first signal line, a portion of a second signal line, and a portion of a third signal line and each test segment circuit is configured to control an operation performed on at least one segment line of the plurality of segment lines.

A method of determining a phase misalignment between a first signal generated from a first signal path and a second signal generated from a second signal path may include obtaining multiple samples of the first signal proximate to when the first signal crosses zero wherein the first signal can be approximated as linear; obtaining multiple samples of the second signal proximate to when the second signal crosses zero wherein the first signal can be approximated as linear; based on the multiple samples of the first signal, approximating a first time at which the first signal crosses zero; based on the multiple samples of the second signal, approximating a second time at which the second signal crosses zero; and determining the phase misalignment between the first signal and the second signal based on a difference between the first time and the second time.

The timing margin of various signal paths in an integrated circuit is monitored by components on the integrated circuit itself. Path margin monitor (PMM) circuits on the integrated circuit receive (a) functional signals propagating along signal paths in the integrated circuit, and (b) corresponding clock signals that are used to clock the functional signals. The PMM circuits output signals (PMM signals) which are indicative of the actual timing margins for the signal paths. For convenience, these will be referred to as path margins. A controller is also integrated on the integrated circuit. The controller controls the PMM circuits. It also receives and analyzes the PMM signals to monitor the path margins across the integrated circuit. Automated software is used to automatically insert instances of the PMM circuits into the design of the integrated circuit. The controller may also be automatically configured and inserted into the design.

Apparatuses including test segment circuits and methods for testing the same are disclosed. An example apparatus includes a plurality of segment lines configured to form a ring around a die and a plurality of test segment circuits, each test segment circuit coupled to at least two segment lines of the plurality of segment lines. Each test segment circuit is coupled to a portion of a first signal line, a portion of a second signal line, and a portion of a third signal line and each test segment circuit is configured to control an operation performed on at least one segment line of the plurality of segment lines.

An apparatus comprising: a functional circuit comprising one or more circuit components configured to perform a function based on one or more first input signals; at least one failure-prediction circuit for use in predicting failure of the functional circuit, the failure-prediction circuit comprising a replica of the functional circuit in terms of constituent circuit components; wherein the failure-prediction circuit is configured to be more susceptible to failure than said functional circuit, wherein the apparatus is configured to provide a prediction of failure of the functional circuit based on a determination of failure of the failure-prediction circuit.

Provided are a method of testing semiconductor device and a system for testing semiconductor device. The method includes measuring a minimum operating voltage of each of a plurality of sample semiconductor devices and an operating frequency of corresponding ring oscillators included in each of the plurality of sample semiconductor devices, generating a model between the operating frequencies of the ring oscillators and the minimum operating voltages of the sample semiconductor devices, measuring an operating frequency of ring oscillators included in a target semiconductor device, and determining a target minimum operating voltage of the target semiconductor device based on the operating frequency of the ring oscillators of the target semiconductor device and the model.

Obtaining a periodic test signal, sampling the periodic test signal using a sampling element according to a sampling clock to generate a sampled periodic output, the sampling element operating according to a supply voltage provided by a voltage regulator, the voltage regulator providing the supply voltage according to a supply voltage control signal, comparing the sampled periodic output to the sampling clock to generate a clock-to-Q measurement indicative of a delay value associated with the generation of the sampled periodic output in response to the sampling clock, generating the supply voltage control signal based at least in part on an average of the clock-to-Q measurement, and providing the supply voltage to a data sampling element connected to the voltage regulator, the data sampling element being a replica of the sampling element, the data sampling element sampling a stream of input data according to the sampling clock.

Embodiments of the invention provide for integrated circuits for testing one or more transistors for process variation effects. According to an embodiment, the integrated circuit can include: a plurality of ring oscillator macro circuits, wherein each ring oscillator macro circuit includes two ring oscillators, a first multiplexer, and a first divide-by-two circuit; a multiplexer stage; a divide-by-two circuit stage; a second multiplexer; a second divide-by-two circuit; and frequency measurement circuit. According to another embodiment, the integrated circuit can include: a first shift register including a plurality of devices-under-test; a second shift register including a plurality of static latches; a first multiplexer configured to receive outputs from each of the plurality of DUTs; a second multiplexer configured to receive outputs from each of the plurality of static latches; and a comparator configured to compare an output from the first multiplexer with an output from the second multiplexer.

An integrated circuit includes first to n.sup.th metal layers vertically stacked on a substrate, and a test circuit outputting a test result signal according to a characteristic of each of the first to n.sup.th metal layers. The test circuit includes first to n.sup.th test circuits for generating a plurality of clock signals. Each clock signal of the plurality of clock signal has a frequency according to a characteristic of a corresponding metal layer among the first to n.sup.th metal layers, and n is a natural number.