Abstract: A gate array is disclosed having a programmable polysilicon layer which serves as both the gate electrodes for MOS transistors and routing lines for some connections between gate electrodes. The gate array structure is formed on a semiconductor substrate and has an array of identical base cells located in a core region of the structure. Each such base cell des the following elements: (1) a plurality of transistors, each of which includes a gate electrode; and (2) one or more gate connection strips formed on the substrate and electrically connecting selected gate electrodes of two or more of the transistors. Preferably, the gate connection strips are made from the same material as the selected gate electrodes (e.g., polysilicon) and are integrally connected therewith. The gate connection strips may patterned (i.e., programmed) to form substrate level routing between gates of various transistors.

Abstract: A circuit for holding constant the propagation delay time at an output terminal in response to an input signal having a varying transition time from one logic state to another logic state at an input terminal is provided. The circuit has a plurality of inverters, each inverter having an input node and an output node, connected in series between the input terminal and the output terminal. The circuit also has a first capacitive means coupled to one of the first inverter output nodes through a switch, and has a means coupled between the input terminal and the switch for engaging the switch to couple the capacitive means to one of the first inverter output nodes. The engaging means is timed to couple the capacitive means responsive to the transition time of the input signal whereby the propagation delay time at the output terminal is constant.

Abstract: A base cell design is disclosed, which base cell design includes ten transistor base cell design that includes (1) a first group of four n-type transistors; (2) a second group of four p-type transistors; and (3) a third group of two n-type transistors. The transistors in the first and second groups have substantially the same gate widths, while the transistors of the third group have a substantially smaller gate width. Further, the transistors of the first and second groups all have gates that are aligned in parallel with a first axis, and the transistors of the third group all have gates that are aligned in parallel with a second axis that is substantially perpendicular to the first axis. The first and second groups of transistors each contain at least one set of two transistors which are connected in series and share a source/drain region.

Abstract: A gate array is disclosed having a programmable polysilicon layer which serves as both the gate electrodes for MOS transistors and routing lines for some connections between gate electrodes. The gate array structure is formed on a semiconductor substrate and has an array of identical base cells located in a core region of the structure. Each such base cell includes the following elements: (1) a plurality of transistors, each of which includes a gate electrode; and (2) one or more gate connection strips formed on the substrate and electrically connecting selected gate electrodes of two or more of the transistors. Preferably, the gate connection strips are made from the same material as the selected gate electrodes (e.g., polysilicon) and are integrally connected therewith. The gate connection strips may patterned (i.e., programmed) to form substrate level routing between gates of various transistors.

Abstract: A process monitor for a CMOS integrated circuit includes first and second delay units that are connected in a ring to constitute a ring oscillator that generates pulses having different phases at the outputs of the delay units respectively. The delay units affect the frequency of the pulses and also the rising and falling edges of the pulses differently depending on the process factor of PMOS and NMOS transistors in the delay units. The process factor can be computed from the frequency, or the ratio of the phase differences between the rising and falling edges of the pulses at the outputs of the first and second delay units. The oscillatory configuration of the monitor is highly sensitive to variations in process factor, and enables the monitor to be embodied by a relatively small number of elements that can fit in two input/output slots in a standard integrated circuit layout.

Abstract: A circuit for holding constant the propagation delay time at an output terminal in response to an input signal having a varying transition time from one logic state to another logic state at an input terminal is provided. The circuit has a plurality of inverters, each inverter having an input node and an output node, connected in series between the input terminal and the output terminal. The circuit also has a first capacitive means coupled to one of the first inverter output nodes through a switch, and has a means coupled between the input terminal and the switch for engaging the switch to couple the capacitive means to one of the first inverter output nodes. The engaging means is timed to couple the capacitive means responsive to the transition time of the input signal whereby the propagation delay time at the output terminal is constant.

Abstract: A process for evaluating acceptability of a digital circuit having a first type of circuit element for a first change of state and a second type of circuit element for a second change of state, the process comprising: generating a leading edge of a first pulse with a pulse generation circuit formed on a substrate in common with the digital circuit and having elements of the first and the second type; generating a trailing edge of a first pulse with a pulse generation circuit formed on a substrate in common with the digital circuit and having elements of the first and the second type; generating an accepted-rejected signal, functionally related to the width of the pulse.

Abstract: A process monitor for a CMOS integrated circuit includes first and second delay units that are connected in a ring to constitute a ring oscillator that generates pulses having different phases at the outputs of the delay units respectively. The delay units affect the frequency of the pulses and also the rising and falling edges of the pulses differently depending on the process factor of PMOS and NMOS transistors in the delay units. The process factor can be computed from the frequency, or the ratio of the phase differences between the rising and falling edges of the pulses at the outputs of the first and second delay units. The oscillatory configuration of the monitor is highly sensitive to variations in process factor, and enables the monitor to be embodied by a relatively small number of elements that can fit in two input/output slots in a standard integrated circuit layout.