Timing based net constraints tagging with zero wire load validation
View Patent ↗A method is provided for facilitating an integrated circuit design layout. The method includes receiving a netlist including a plurality of subnets. For each subnet, the method also includes obtaining a Steiner net length value and related net delays in a signal path for a metal wiring layer using timings of all involved circuits of the subnet, and determining whether the net delay is smaller than a predefined value. On a negative outcome of the determination, a wire delay is ascertained for the named metal wiring layer based on a maximum buffer distance retrieved from a cycle reach table, and determining whether the ascertained wire delay is below the related net delay. On a positive outcome of the second determination, a next increased metal wire width is selected and a metal wire based wire delay for the named metal wiring layer including a buffer is ascertained.
1. A method in a data processing system for timing based net constraints tagging within a multi-layer integrated circuit design layout, the method comprising:
receiving a hierarchical netlist characterizing the multi-layer integrated circuit design layout, wherein the netlist includes a plurality of subnets, each subnet comprising a plurality of partial circuits; and
for each subnet, processing the subnet to facilitate laying out wiring for the multi-layer integrated circuit design, the processing facilitating providing a complete netlist with wiring layout, and including the following:
ascertaining a Steiner net length value between the subnets and partial circuits and related net delays of all subnets and partial circuits in a signal path defined by the hierarchical netlist for a named metal wiring layer using timing characteristics of each source circuit and related sink circuit of the subnet;
determining, in a first determination, whether the net delay is not larger than a predefined delay value;
on a negative outcome of the first determination, ascertaining a metal wire based wire delay for the named metal wiring layer based on a maximum buffer distance retrieved from a cycle reach table;
determining, in a second determination, whether the ascertained metal wire based wire delay is below the related net delay;
on a positive outcome of the second determination, selecting a next increased width of the metal wire out of the cycle reach table;
continuing with the ascertaining of a metal wire based wire delay for the named metal wiring layer including a buffer; and
initiating fabrication of the multi-layer integrated circuit using the complete netlist with wiring layout.
2. The method according to claim 1 , wherein the hierarchical netlist defines a timing based on a slack, a slew, a driver strength of all of the source circuits and a pin capacitance of all of the subnets and partial circuits within the hierarchical netlist.
3. The method according to claim 1 , further comprising, based on a negative outcome of the second determination, selecting timing delays of the named metal wiring layer and the metal wire width from the cycle reach table.
4. The method according to claim 1 , wherein the selecting a next increased width of the metal wire also comprises increasing a number of the named metal wire layer if a maximum width value has been exceeded.
5. The method according to claim 1 , wherein the selecting a next increased width of the metal wire also comprises highlighting the related subnet based on the number of the named metal wire layer exceeding a predefined maximum layer number.
6. The method according to claim 1 , wherein the ascertaining a metal wire based wire delay for the named metal wiring layer including at least one buffer comprises:
using a cycle and buffer delay table comprising a predefined buffer delay value as well as a delay table defining wire delays based on a mix of used metal materials, a metal material width, and individual ratios of the mixed used metal materials.
7. The method according to claim 1 , wherein the cycle read table includes at least one selected out of the group comprising a metal type, the width of the metal type, the delay and a the maximum buffer distance.
8. A system for timing based net constraints tagging within a multi-layer integrated circuit design layout, the system comprising:
a memory; and
a processor communicatively coupled to the memory, wherein the system performs a method comprising:
receiving a hierarchical netlist characterizing the multi-layer integrated circuit design layout, wherein the netlist includes a plurality of subnets, each subnet comprising a plurality of partial circuits; and
for each subnet, processing the subnet to facilitate laying out wiring for the multi-layer integrated circuit design, the processing facilitating providing a complete netlist with wiring layout, and including the following:
ascertaining a Steiner net length value between the subnets and partial circuits and related net delays of all subnets and partial circuits in a signal path defined by the hierarchical netlist for a named metal wiring layer using timing characteristics of each source circuit and related sink circuit of the subnet;
determining, in a first determination, whether the net delay is not larger than a predefined delay value;
on a negative outcome of the first determination, ascertaining a metal wire based wire delay for the named metal wiring layer based on a maximum buffer distance retrieved from a cycle reach table;
determining, in a second determination, whether the ascertained metal wire based wire delay is below the related net delay;
on a positive outcome of the second determination, selecting a next increased width of the metal wire out of the cycle reach table;
continuing with the ascertaining of a metal wire based wire delay for the named metal wiring layer including a buffer; and
initiating fabrication of the multi-layer integrated circuit using the complete netlist with wiring layout.
9. The system according to claim 8 , wherein the hierarchical netlist defines a timing based on a slack, a slew, a driver strength of all of the source circuits and a pin capacitance of all of the subnets and partial circuits within the hierarchical netlist.
10. The system according to claim 8 , further comprising, based on a negative outcome of the second determination selecting timing delays of the named metal wiring layer and the metal wire width from the cycle reach table.
11. The system according to claim 8 , wherein the selecting a next increased width of the metal wire also comprises increasing a number of the named metal wire layer if a maximum width value has been exceeded.
12. The method according to claim 8 , wherein the selecting a next increased width of the metal wire also comprises highlighting the related subnet based on the number of the named metal wire layer exceeding a predefined maximum layer number.
13. The system according to claim 8 , wherein the ascertaining a metal wire based wire delay for the named metal wiring layer including at least one buffer comprises:
using a cycle and buffer delay table comprising a predefined buffer delay value as well as a delay table defining wire delays based on a mix of used metal materials, a metal material width, and individual ratios of the mixed used metal materials.
14. The system according to claim 8 , wherein the cycle read table includes at least one selected out of the group comprising a metal type, the width of the metal type, the delay and a the maximum buffer distance.
15. A computer program product for timing based net constraints tagging within a multi-layer integrated circuit design layout, the computer program product comprising:
a non-transitory computer readable storage medium having program instructions embodied therewith, the program instructions being executable by one or more computing systems to cause the one or more computing systems to:
receive a hierarchical netlist characterizing the multi-layer integrated circuit design layout, wherein the netlist includes a plurality of subnets, each subnet comprising a plurality of partial circuits; and
for each subnet, processing the subnet to facilitate laying out wiring for the multi-layer integrated circuit design, the processing facilitating providing a complete netlist with wiring layout, and including the following:
ascertaining a Steiner net length value between the subnets and partial circuits and related net delays of all subnets and partial circuits in a signal path defined by the hierarchical netlist for a named metal wiring layer using timing characteristics of each source circuit and related sink circuit of the subnet;
determining, in a first determination, whether the net delay is not larger than a predefined delay value;
on a negative outcome of the first determination, ascertaining a metal wire based wire delay for the named metal wiring layer based on a maximum buffer distance retrieved from a cycle reach table;
determining, in a second determination, whether the ascertained metal wire based wire delay is below the related net delay;
on a positive outcome of the second determination, selecting a next increased width of the metal wire out of the cycle reach table;
continuing with the ascertaining of a metal wire based wire delay for the named metal wiring layer including a buffer; and
initiating fabrication of the multi-layer integrated circuit using the complete netlist with wiring layout.
16. The computer program product of claim 15 , wherein the hierarchical netlist defines a timing based on a slack, a slew, a driver strength of all of the source circuits and a pin capacitance of all of the subnets and partial circuits within the hierarchical netlist.
17. The computer program product of claim 15 , further comprising, based on a negative outcome of the second determination, selecting timing delays of the named metal wiring layer and the metal wire width from the cycle reach table.
18. The computer program product of claim 15 , wherein the selecting a next increased width of the metal wire also comprises increasing a number of the named metal wire layer if a maximum width value has been exceeded.
19. The computer program product of claim 15 , wherein the selecting a next increased width of the metal wire also comprises highlighting the related subnet based on the number of the named metal wire layer exceeding a predefined maximum layer number.
20. The computer program product of claim 15 , wherein the ascertaining a metal wire based wire delay for the named metal wiring layer including at least one buffer comprises:
using a cycle and buffer delay table comprising a predefined buffer delay value as well as a delay table defining wire delays based on a mix of used metal materials, a metal material width, and individual ratios of the mixed used metal materials.