US 6,389,584 B1 · Gate input protection with a reduced number of antenna diodes

Abstract

Antenna diodes reduction. The number of antenna diodes is reduced in order to achieve an improved integrated circuit (IC) performance in terms of speed and power consumption. Essentially, before the number of antenna diodes can be reduced interconnect segments at a metal layer and metal layers below it are checked to find out if there are any segments of interconnects to gate inputs that are not yet connected to an output of a signal source. Further, a ratio is established for each segment of interconnect to gate input(s) that is not yet connected to an output. The ratio relates to the physical characteristics of the gate and interconnect and is expressed as the relationship between the gate area and area of the interconnect segments that are not yet connected to the signal source. The ratio is then compared against a set criteria such as an upper limit of the ratio. Finally, based on this comparison and the number of gate inputs attached to the interconnect, a decision is made whether to reduce the number of antenna diodes. Once a decision is made, the number of antenna diodes is adjusted accordingly by removing antenna diodes or by reducing the number of antenna diodes to be added. In accordance with a purpose of the invention, a computer system can be used in which an embodiment of the invention is implemented. The invention can be implemented in the computer system as a separate design automation tool or as part of other design automation tools. The invention can be embodied in the computer system in the form of computer program code stored in a computer readable medium.

Claims43

Dependent claims

A method for minimizing the number of antenna diodes, comprising:

selecting a segment of an interconnect routed in one or more metal layers of an integrated circuit (IC);
determining whether the selected interconnect is attached to any gate input and, if so, further determining whether the selected segment is connected to a signal source;
determining whether the selected segment is at the lowest metal layer for the routed interconnect if the selected segment is already connected to a signal source and, if the selected segment is at the lowest metal layer, excluding all antenna diodes from all gate inputs that are attached to the selected segment, wherein protection of each gate input is maintained;
and
determining whether to adjust the number of antenna diodes associated with gate inputs that are attached to the selected segment if the selected segment is not connected to the signal source, including:
determining an interconnect area;
determining a gate area;
determining a ratio between the interconnect area and the gate area;
determining, based on criteria including the ratio, whether to reduce to a minimum the number of antenna diodes;
and
minimizing the number of antenna diodes if it is so determined, wherein protection of each gate input is maintained.

8 more elements

An apparatus for minimizing the number of antenna diodes, comprising:

means for selecting a segment of an interconnect routed in one or more metal layers of an integrated circuit (IC);
means for determining whether the selected segment is attached to any gate input and, if so, further determining whether the selected segment is connected to a signal source;
means for determining whether the selected segment is at the lowest metal layer for the routed interconnect if the selected segment is already connected to a signal source and, if the selected segment is at the lowest metal layer, for excluding all antenna diodes from all gate inputs that are attached to the selected segment, wherein protection of each gate input is maintained;
and
means for determining whether to adjust the number of antenna diodes associated with gate inputs that are attached to the selected segment if the selected segment is not yet connected to the signal source, including:
means for determining an interconnect area;
means for determining a gate area;
means for determining a ratio between the interconnect area and the gate area;
means for determining, based on criteria including the ratio, whether to reduce to a minimum the number of antenna diodes;
and
means for minimizing the number of antenna diodes if it is so determined, wherein protection of each gate input is maintained.

8 more elements

An integrated circuit (IC), comprising:

gate inputs;
interconnects routed in one or more metal layers of the IC, and attached to at least one of the gate inputs, the interconnects forming signal routes;
and
gate inputs protection designed with a reduced number of antenna diodes provided by a diodes number reduction engine capable of:
selecting the signal routes one at a time until all signal routes in the IC have been selected;
selecting the interconnects for each selected signal route one at a time until all interconnects of each selected signal route have been selected;
selecting segments of each selected interconnect one at a time until all the segments of each selected interconnect have been selected;
and
performing steps for each selected segment of:
determining whether the selected segment is attached to any gate input and, if so, further determining whether the selected segment is connected to a signal source;
and
determining whether the selected segment is at the lowest metal layer for the routed interconnect if the selected segment is already connected to a signal source and, if the selected segment is at the lowest metal layer, for excluding all antenna diodes from all gate inputs that are attached to the selected segment, wherein protection of each gate input is maintained;
wherein, for each selected segment, the diodes number reduction engine is further capable of:
determining whether to adjust the number of antenna diodes associated with gate inputs that are attached to the selected segment if the selected segment is not connected to the signal source, including:
determining an interconnect area;
determining a gate area;
determining a ratio between the interconnect area and the gate area;
determining, based on criteria including the ratio, whether to reduce the number of antenna diodes;
and
reducing the number of antenna diodes if it is so determined, wherein protection of each gate input is maintained.

17 more elements

Dependencies are inferred from the claim text.

Gate input protection with a reduced number of antenna diodes

Life of this patent

Gate input protection with a reduced number of antenna diodes

Life of this patent

Abstract

Claims43