Integrated circuit chip reliability qualification using a sample-specific expected fail rate

A method comprising:

• sorting integrated circuit chips manufactured according to a design into groups of integrated circuit chips, said groups corresponding to different process windows within a process distribution for said design;
• and,
• performing reliability qualification of said integrated circuit chips, said performing of said reliability qualification comprising:
• determining group fail rates for said groups;
• determining an expected overall fail rate for said integrated circuit chips, said expected overall fail rate being based on said group fail rates;
• selecting a sample of said integrated circuit chips from at least one of said groups;
• identifying all specific groups from which said sample was selected;
• determining percentages of said sample selected from said specific groups and specific group fail rates for said specific groups;
• determining an expected sample fail rate for said sample, said expected sample fail rate being determined considering said percentages and said specific group fail rates and being different from said expected overall fail rate;
• stress testing said sample to determine an actual sample fail rate for said sample;
• and,
• comparing said expected sample fail rate to said actual sample fail rate.

A method comprising:

• sorting integrated circuit chips manufactured according to a design into groups of integrated circuit chips, said groups corresponding to different process windows within a process distribution for said design;
• and,
• performing reliability qualification of said integrated circuit chips, said performing of said reliability qualification comprising:
• determining group fail rates for said groups;
• determining an expected overall fail rate for said integrated circuit chips, said expected overall fail rate being based on said group fail rates;
• selecting a sample of said integrated circuit chips from at least one of said groups;
• identifying all specific groups from which said sample was selected;
• determining percentages of said sample selected from said specific groups and specific group fail rates for said specific groups;
• determining an expected sample fail rate for said sample, said expected sample fail rate being calculated as a sum of fail rate contributions from said specific groups, each fail rate contribution of each specific group comprising a product of a specific group fail rate determined for said specific group multiplied by a percentage of said sample selected from said specific group;
• stress testing said sample to determine an actual sample fail rate for said sample;
• and,
• comparing said expected sample fail rate to said actual sample fail rate.