US 5,489,856 AGranted

Laser-programmable clocked-logic integrated-circuit

AssigneeThe United States of America as represented by the Director, National Security Agency

InventorsJohn A. Rimshaw, Daniel A. Anthony

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Abstract

A laser-programmable clocked-logic integrated-circuit cell having a transmission gate; a first laser-cut area; a first two-input nand gate; a second two-input nand gate; a third two-input nand gate; a first inverter; a first tri-state clocked-inverter; a second laser-cut area; a second inverter; a third inverter; a second tri-state clocked-inverter; a third laser-cut area; a fourth two-input nand gate; a fifth two-input nand gate; a sixth two-input nand gate; a fourth inverter; a third tri-state clocked-inverter; a fourth tri-state clocked-inverter; a first laser-link area; a second laser-link area; a fourth laser-cut area; a fifth laser-cut area; and a third laser-link area.

Claims6

Dependent claims

A laser-programmable clocked-logic integrated-circuit cell, comprising:

(a) a transmission gate, having an input that traverses said cell, having a first control-input, having a second control-input, and having an output;
(b) a first laser-cut means comprising a metal line having a first end and a second end, where the first end of said first laser-cut means is connected to the output of said transmission gate;
(c) a first two-input nand gate, having a first input connected to the second end of said first laser-cut means, having a second input that traverses said cell, and having an output, where the first input to said first nand gate traverses said cell;
(d) a second two-input nand gate, having a first input connected to the output of said first nand gate, having a second input, and having an output that traverses said cell;
(e) a third two-input nand gate, having a first input that traverses said cell, having a second input that traverses said cell, and having an output connected to the second input of said second nand gate;
(f) a first inverter, having an input connected to the output of said second nand gate, and having an output that traverses said cell;
(g) a first tri-state clocked-inverter, having an input connected to the output of said first inverter, having a clock-input connected to the second control-input of said transmission gate, and having an output connected to the output of said transmission gate;
(h) a second laser-cut means comprising a metal line having a first end and a second end, where the first end of said second laser-cut means runs the width of said cell;
(i) a second inverter, having a first input connected to the second end of said second laser-cut means, and having an output connected to the clock-input of said first tri-state clocked-inverter;
(j) a third inverter, having an input connected to the output of said second inverter, and having an output connected to the first control-input of said transmission gate;
(k) a second tri-state clocked-inverter, having an input connected to the output of said first inverter, having a clocked-input connected to the output of said second inverter, and having an output;
(l) a third laser-cut means comprising a metal line having a first end and a second end, where the first end of said third laser-cut means is connected to the output of said second tri-state clocked-inverter;
(m) a fourth two-input nand gate, having a first input connected to the second end of said third laser-cut means, having a second input that traverses said cell, and having an output, where the first input of said fourth nand gate traverses said cell;
(n) a fifth two-input nand gate, having a first input connected to the output of said fourth nand gate, having a second input, and having an output that traverses said cell;
(o) a sixth two-input nand gate, having a first input that traverses said cell, having a second input that traverses said cell, and having an output connected to the second input of said fifth nand gate;
(p) a fourth inverter, having an input connected to the output of said fifth nand gate, and having an output that traverses said cell;
(q) a third tri-state clocked-inverter, having an input connected to the output of said fourth inverter, having a clock-input connected to the output of said third inverter, and having an output connected to the output of said second tri-state clocked-inverter;
(r) a fourth tri-state clocked-inverter, having an input connected to the output of said fourth inverter, having a clock-input, and having an output;
(s) a first laser-link means, comprising
(i) a first metal line,
(ii) a second metal line adjacent to, and electrically isolated from, said first metal line;
and
(iii) a via over said first metal line and said second metal line so that said first metal line and said second metal line may be fused together with a laser, where the first metal line of said first laser-link means is connected to the input of said second inverter, and where the second metal line of said first laser-link means traverses said cell;
(t) a second laser-link means, comprising
(i) a first metal line,
(ii) a second metal line adjacent to, and electrically isolated from, said first metal line;
and
(iii) a via over said first metal line and said second metal line so that said first metal line and said second metal line may be fused together with a laser, where said first metal line of said second laser-link means is connected to the second metal line of said first laser-link means, and where said second metal line of said second laser-link means is connected to the clocked-input of said fourth tri-state clocked-inverter;
(u) a fourth laser-cut means comprising a metal line having a first end connected to the second metal line of said second laser-link means, and having a second end that traverses said cell;
(v) a fifth laser-cut means comprising a metal line having a first end connected to the output of said fourth tri-state clocked-inverter, and having a second end runs the width of said cell;
and
(w) a third laser-link means, comprising
(i) a first metal line,
(ii) a second metal line adjacent to, and electrically isolated from, said first metal line;
and
(iii) a via over said first metal line and said second metal line so that said first metal line and said second metal line may be fused together with a laser, where said first metal line of said third laser-link means is connected to the output of said fourth tri-state clocked-inverter, and where the second metal line of said third laser-link means traverses said cell.

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Dependencies are inferred from the claim text.

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Abstract

A laser-programmable clocked-logic integrated-circuit cell, comprising:

(a) a transmission gate, having an input that traverses said cell, having a first control-input, having a second control-input, and having an output;
(b) a first laser-cut means comprising a metal line having a first end and a second end, where the first end of said first laser-cut means is connected to the output of said transmission gate;
(c) a first two-input nand gate, having a first input connected to the second end of said first laser-cut means, having a second input that traverses said cell, and having an output, where the first input to said first nand gate traverses said cell;
(d) a second two-input nand gate, having a first input connected to the output of said first nand gate, having a second input, and having an output that traverses said cell;
(e) a third two-input nand gate, having a first input that traverses said cell, having a second input that traverses said cell, and having an output connected to the second input of said second nand gate;
(f) a first inverter, having an input connected to the output of said second nand gate, and having an output that traverses said cell;
(g) a first tri-state clocked-inverter, having an input connected to the output of said first inverter, having a clock-input connected to the second control-input of said transmission gate, and having an output connected to the output of said transmission gate;
(h) a second laser-cut means comprising a metal line having a first end and a second end, where the first end of said second laser-cut means runs the width of said cell;
(i) a second inverter, having a first input connected to the second end of said second laser-cut means, and having an output connected to the clock-input of said first tri-state clocked-inverter;
(j) a third inverter, having an input connected to the output of said second inverter, and having an output connected to the first control-input of said transmission gate;
(k) a second tri-state clocked-inverter, having an input connected to the output of said first inverter, having a clocked-input connected to the output of said second inverter, and having an output;
(l) a third laser-cut means comprising a metal line having a first end and a second end, where the first end of said third laser-cut means is connected to the output of said second tri-state clocked-inverter;
(m) a fourth two-input nand gate, having a first input connected to the second end of said third laser-cut means, having a second input that traverses said cell, and having an output, where the first input of said fourth nand gate traverses said cell;
(n) a fifth two-input nand gate, having a first input connected to the output of said fourth nand gate, having a second input, and having an output that traverses said cell;
(o) a sixth two-input nand gate, having a first input that traverses said cell, having a second input that traverses said cell, and having an output connected to the second input of said fifth nand gate;
(p) a fourth inverter, having an input connected to the output of said fifth nand gate, and having an output that traverses said cell;
(q) a third tri-state clocked-inverter, having an input connected to the output of said fourth inverter, having a clock-input connected to the output of said third inverter, and having an output connected to the output of said second tri-state clocked-inverter;
(r) a fourth tri-state clocked-inverter, having an input connected to the output of said fourth inverter, having a clock-input, and having an output;
(s) a first laser-link means, comprising
(i) a first metal line,
(ii) a second metal line adjacent to, and electrically isolated from, said first metal line;
and
(iii) a via over said first metal line and said second metal line so that said first metal line and said second metal line may be fused together with a laser, where the first metal line of said first laser-link means is connected to the input of said second inverter, and where the second metal line of said first laser-link means traverses said cell;
(t) a second laser-link means, comprising
(i) a first metal line,
(ii) a second metal line adjacent to, and electrically isolated from, said first metal line;
and
(iii) a via over said first metal line and said second metal line so that said first metal line and said second metal line may be fused together with a laser, where said first metal line of said second laser-link means is connected to the second metal line of said first laser-link means, and where said second metal line of said second laser-link means is connected to the clocked-input of said fourth tri-state clocked-inverter;
(u) a fourth laser-cut means comprising a metal line having a first end connected to the second metal line of said second laser-link means, and having a second end that traverses said cell;
(v) a fifth laser-cut means comprising a metal line having a first end connected to the output of said fourth tri-state clocked-inverter, and having a second end runs the width of said cell;
and
(w) a third laser-link means, comprising
(i) a first metal line,
(ii) a second metal line adjacent to, and electrically isolated from, said first metal line;
and
(iii) a via over said first metal line and said second metal line so that said first metal line and said second metal line may be fused together with a laser, where said first metal line of said third laser-link means is connected to the output of said fourth tri-state clocked-inverter, and where the second metal line of said third laser-link means traverses said cell.

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