Universal two-input logic gate that is configurable and connectable in an integrated circuit by a single mask layer adjustment
AssigneeNational Semiconductor Corporation
InventorJane Xin-LeBlanc
Life of this patent
Estimating the term…
Abstract
A spare logic circuit for implementing any one of a plurality of logic gates includes a multiplexer circuit whose select inputs are utilized as logic gate inputs, and whose output is utilized as a logic gate output. Each of a plurality of data inputs of the multiplexer circuit is configured to receive one of first and second logic voltage levels which define the desired logic function. By modifying a single photolithographic mask, the spare logic gate can be: configured to perform the desired logic function; connected into a target logic circuit; or both configured and connected into a target logic circuit.
Claims21
1-12. (canceled)
A semiconductor integrated circuit apparatus, comprising:
- a plurality of metal layers;
- a plurality of via layers, each via layer including vias that interconnect two of the metal layers;
- and
- an unused logic gate having an input node, the via layers connected to the input node to make the input node electrically accessible on all of the metal layers.
A circuit for implementing any one of a plurality of logic gates, comprising:
- first and second logic gate inputs;
- a multiplexer circuit having first and second select inputs respectively connected to the first and second logic gate inputs, the multiplexer circuit also having a plurality of data inputs, each data input configured to receive one of first and second logic voltage levels, the multiplexer circuit including an output;
- and
- a logic gate output connected to the output of the multiplexer circuit.
A semiconductor integrated circuit apparatus, comprising:
- a spare logic gate comprising a first control input and multiple data inputs;
- and
- a photolithographic mask associated with at least a first metal layer and configured to be modified to:
- connect a node of a target logic circuit to the first control input;
- and
- connect at least one of the data inputs to a supply voltage.
Dependencies are inferred from the claim text.