Optimal pad location method for microelectronic circuit cell placement
First Claim
1. A method for optimally locating a plurality of electrical terminals on a border of a microelectronic circuit that includes a plurality of cells, comprising the steps of:
- (a) performing a placement of said cells;
(b) calculating cell interconnect points in said placement corresponding to the electrical terminals respectively;
(c) calculating positions on said border at which distances between said positions and said interconnect points are minimum respectively; and
(d) locating the terminals at said positions respectively, in which;
step (c) enables said positions to be calculated such that the terminals can overlap after performing step (d); and
the method further comprises the steps, performed after step (d), of;
(e) calculating adjusted positions for said terminals respectively in accordance with a predetermined function such that said overlap is eliminated; and
(f) locating the terminals at said adjusted positions respectively;
step (c) comprises calculating said positions in two-dimensional coordinates respectively; and
step (e) comprises the substeps of;
(g) converting said positions into one-dimensional coordinates measured along said border respectively;
(h) calculating said adjusted positions in one-dimensional coordinates; and
(i) converting said adjusted positions into two-dimensional coordinates.
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Accused Products
Abstract
A cell placement is generated for a microelectronic circuit chip. Interconnect points for cell nets are calculated, for example, as gravity points of the cells of the respective nets. Optimal positions for external connection terminals or pads along the border of the circuit are calculated as being the closest positions to the respective interconnect points. The total wirelength of the placement is calculated as including the distances between the interconnect points and the respective pads. Where initial location of the pads results in overlap thereof, clusters of pads are identified and expanded to remove the overlap. Concatenated overlapping clusters resulting from expansion are treated as new clusters and subsequently expanded until all overlap is eliminated. The centers of gravity of the clusters are preserved. During the overlap removal process, initial rectangular coordinates of the pad positions are converted into linear coordinates along the border. After the overlap is eliminated, the linear coordinates are converted back to rectangular coordinates.
33 Citations
7 Claims
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1. A method for optimally locating a plurality of electrical terminals on a border of a microelectronic circuit that includes a plurality of cells, comprising the steps of:
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(a) performing a placement of said cells; (b) calculating cell interconnect points in said placement corresponding to the electrical terminals respectively; (c) calculating positions on said border at which distances between said positions and said interconnect points are minimum respectively; and (d) locating the terminals at said positions respectively, in which; step (c) enables said positions to be calculated such that the terminals can overlap after performing step (d); and the method further comprises the steps, performed after step (d), of; (e) calculating adjusted positions for said terminals respectively in accordance with a predetermined function such that said overlap is eliminated; and (f) locating the terminals at said adjusted positions respectively; step (c) comprises calculating said positions in two-dimensional coordinates respectively; and step (e) comprises the substeps of; (g) converting said positions into one-dimensional coordinates measured along said border respectively; (h) calculating said adjusted positions in one-dimensional coordinates; and (i) converting said adjusted positions into two-dimensional coordinates.
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2. A method for optimally locating a plurality of electrical terminals on a border of a microelectronic circuit that includes a plurality of cells, comprising the steps of:
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(a) performing a placement of said cells; (b) calculating cell interconnect points in said placement corresponding to the electrical terminals respectively; (c) calculating positions on said border at which distances between said positions and said interconnect points are minimum respectively; and (d) locating the terminals at said positions respectively, in which; step (c) enables said positions to be calculated such that the terminals can overlap after performing step (d); and the method further comprises the steps, performed after step (d), of; (e) calculating adjusted positions for said terminals respectively in accordance With a predetermined function such that said overlap is eliminated; and (f) locating the terminals at said adjusted positions respectively; step (c) comprises calculating said positions in rectangular coordinates respectively; and step (e) comprises the substeps of; (g) converting said positions into linear coordinates measured along said border respectively; (h) calculating said adjusted positions in linear coordinates; and (i) converting said adjusted positions into rectangular coordinates.
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3. A method for removing overlap between electrical terminals on a border of a microelectronic circuit resulting from initial location of the terminals at positions that allow said overlap, comprising the steps of:
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(a) identifying overlapping clusters of terminals; (b) calculating adjusted positions for said terminals of said clusters respectively in accordance with a predetermined function such that said overlap is eliminated; and (c) locating the terminals at said adjusted positions respectively, in which; said positions are specified in two-dimensional coordinates prior to performing step (a) respectively; and step (b) comprises the substeps of; (d) converting said positions into one-dimensional coordinates measured along said border respectively; (e) calculating said adjusted positions in one-dimensional coordinates; and (f) converting said adjusted positions into two-dimensional coordinates. - View Dependent Claims (4, 5)
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6. A method for removing overlap between electrical terminals on a border of a microelectronic circuit resulting from initial location of the terminals at positions that allow said overlap, comprising the steps of:
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(a) identifying overlapping clusters of terminals; (b) calculating adjusted positions for said terminals of said clusters respectively in accordance with a predetermined function such that said overlap is eliminated; and (c) locating the terminals at said adjusted positions respectively, in which; said positions are specified in rectangular coordinates prior to performing step (a) respectively; and step (b) comprises the substeps of; (d) converting said positions into linear coordinates measured along said border respectively; (e) calculating said adjusted positions in linear coordinates; and (f) converting said adjusted positions into rectangular coordinates. - View Dependent Claims (7)
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Specification