System and method for detecting parasitic thyristors in an integrated circuit

A method of checking an integrated circuit layout database for parasitic thyristors, the method comprising:

• retrieving an integrated circuit layout database a non-transitory computer readable medium;
• identifying hot pad diffusion sites, identifying hot pad diffusion sites comprising identifying diffusion sites in the layout databases that are coupled to pads.
• identifying parasitic thyristor structures in the layout database by using a computer, identifying parasitic thyristor structures comprising:
• identifying anode regions, cathode regions and well regions,
• determining that particular anode regions, cathode regions and well regions comprise an identified parasitic thyristor if a distance between an anode region and a cathode region is less than a second threshold, wherein the parasitic thyristor structures are different from the identified hot pad diffusion sites;
• and
• flagging a violation when a distance between an identified parasitic thyristor and an identified hot pad diffusion site is less than a first threshold.

A non-transitory computer readable medium with an executable program stored thereon, wherein the program instructs a processor to perform the following steps:

• identifying hot pad diffusion sites in a layout database, identifying hot pad diffusion sites comprising identifying diffusion sites in the layout databases that are coupled to pads.
• identifying parasitic thyristor structures in the layout database, identifying parasitic thyristor structures comprising:
• identifying anode regions, cathode regions and well regions,
• determining that particular anode regions, cathode regions and well regions comprise an identified parasitic thyristor if a distance between an anode region and a cathode region is less than a second threshold, wherein the parasitic thyristor structures are different from the identified hot pad diffusion sites;
• and
• flagging a violation when a distance between an identified parasitic thyristor and an identified hot pad diffusion site is less than a first threshold.

A method comprising:

• retrieving a layout of an integrated circuit design from a non-transitory computer readable medium;
• identifying a silicon controlled rectifier (SCR) structure in the layout by using a computer;
• identifying a current injection site in the layout;
• determining if a distance between the identified current injection site and the identified SCR structure and is less than a first threshold, wherein the distance between the identified current injection site and the identified SCR structure is zero when the current injection site is coincident with an anode or a cathode of the identified SCR structure;
• wherein identifying the silicon controller rectifier structure comprises:
• identifying a structure comprising an anode and a cathode;
• determining when a distance between the anode and the cathode is less than a second threshold;
• and
• when the distance is less than the second threshold, identifying the structure as the identified SCR structure;
• and
• flagging a violation if the determined distance is less than the first threshold.

A method comprising:

• retrieving a layout of an integrated circuit design from a non-transitory computer readable medium;
• and
• identifying a silicon controlled rectifier (SCR) structure in the layout by using a computer,
• identifying a current injection site in the layout, wherein the current injection site is different from the identified SCR structure, identifying the SCR structure comprising
• identifying a structure comprising an anode and a cathode,
• determining a nominal potential difference between the anode and the cathode,
• adjusting a threshold to be proportional to the nominal potential difference between the anode and the cathode,
• determining when a distance between the anode and the cathode is less than the threshold, and
• when the distance is less than the threshold, identifying the structure as the identified SCR structure.

A method comprising:

• retrieving a layout of an integrated circuit design from a non-transitory computer readable medium;
• identifying a silicon controlled rectifier (SCR) structure in the layout by using a computer, wherein identifying the silicon controlled rectifier structure comprises:
• identifying a structure comprising an anode and a cathode,
• determining when a distance between the anode and the cathode is less than a second threshold, and
• when the distance is less than the second threshold, identifying the structure as the identified SCR structure;
• determining a SCR category of the identified SCR structure from a plurality of SCR categories, wherein determining the category comprises:
• determining that the identified SCR structure is in a first category when the anode is disposed in a floating n-well, and
• determining that the identified SCR structure is in a second category when the anode is disposed in an n-well that is configured to be coupled to a power supply node;
• adjusting the first threshold according to the determined SCR category;
• identifying a current injection site in the layout;
• determining when a distance between the identified current injection site and the identified SCR structure and is less than a first threshold;
• and
• flagging a violation when the determined distance is less than the first threshold.