Simulation method and simulation apparatus

A non-transitory computer-readable recording medium having stored therein a simulation program for causing a computer to execute a simulation process comprising:

• producing, by a processor, a first wiring board internal structure model for a basic line length including one first glass cloth at the upper side of a pair of first differential lines by modeling an internal structure of a wiring board using a three-dimensional numerical analysis program, and producing, by a processor, a second wiring board internal structure model for a basic line length including one second glass cloth at the lower side of a pair of second differential lines by modeling an internal structure of a wiring board using a three-dimensional numerical analysis program;
• producing, by a processor, a plurality of first positional patterns having different relative positional relationships between the first differential lines and the first glass cloth by varying relative positional relationships between the first differential lines and the first glass cloth of the first wiring board internal structure model using a three-dimensional numerical analysis program, and producing, by a processor, a plurality of second positional patterns having different relative positional relationships between the second differential lines and the second glass cloth by varying relative positional relationships between the second differential lines and the second glass cloth of the second wiring board internal structure model using a three-dimensional numerical analysis program;
• calculating, by a processor, by performing a three-dimensional electromagnetic field analysis using a three-dimensional numerical analysis program for each of the plurality of first positional patterns, a first skew generated between the pair of first differential lines in each of the plurality of first positional patterns, and calculating, by a processor, by performing a three-dimensional electromagnetic field analysis using a three-dimensional numerical analysis program for each of the plurality of second positional patterns, a second skew generated between the pair of second differential lines in each of the plurality of second positional patterns;
• and
• calculating, by a processor, for each of a plurality of wiring board patterns configured by combining a plurality of first combination patterns individually configured by combining the plurality of first positional patterns of the first wiring board internal structure model for a certain line length and a plurality of second combination patterns individually configured by combining the plurality of second positional patterns of the second wiring board internal structure model for a certain line length, a total skew by adding a sum of the first skews obtained by summing the first skew of each of the plurality of first positional patterns configuring each of the plurality of first combination patterns to a sum of the second skews obtained by summing the second skew of each of the plurality of second positional patterns configuring each of the plurality of second combination patterns, and then acquiring a skew distribution in a wiring board having a certain line length based on the calculated total skews.

A simulation apparatus, comprising:

• a processor;
• wherein the processor configured to execute a process including:
• producing a first wiring board internal structure model for a basic line length including one first glass cloth at the upper side of a pair of first differential lines by modeling an internal structure of a wiring board using a three-dimensional numerical analysis program, and producing a second wiring board internal structure model for a basic line length including one second glass cloth at the lower side of a pair of second differential lines by modeling an internal structure of a wiring board using a three-dimensional numerical analysis program;
• producing a plurality of first positional patterns having different relative positional relationships between the first differential lines and the first glass cloth by varying relative positional relationships between the first differential lines and the first glass cloth of the first wiring board internal structure model using a three-dimensional numerical analysis program, and producing a plurality of second positional patterns having different relative positional relationships between the second differential lines and the second glass cloth by varying relative positional relationships between the second differential lines and the second glass cloth of the second wiring board internal structure model using a three-dimensional numerical analysis program;
• calculating, by performing a three-dimensional electromagnetic field analysis using a three-dimensional numerical analysis program for each of the plurality of first positional patterns, a first skew generated between the pair of first differential lines in each of the plurality of first positional patterns, and calculating, by performing a three-dimensional electromagnetic field analysis using a three-dimensional numerical analysis program for each of the plurality of second positional patterns, a second skew generated between the pair of second differential lines in each of the plurality of second positional patterns;
• and
• calculating, for each of a plurality of wiring board patterns configured by combining a plurality of first combination patterns individually configured by combining the plurality of first positional patterns of the first wiring board internal structure model for a certain line length and a plurality of second combination patterns individually configured by combining the plurality of second positional patterns of the second wiring board internal structure model for a certain line length, a total skew by adding a sum of the first skews obtained by summing the first skew of each of the plurality of first positional patterns configuring each of the plurality of first combination patterns to a sum of the second skews obtained by summing the second skew of each of the plurality of second positional patterns configuring each of the plurality of second combination patterns, and then acquires a skew distribution in a wiring board having a certain line length based on the calculated total skews.