Impact of Redundancy on Yield

1
Impact of Redundancy on Yield

• n x m array with s spare columns
• The probability that any one element will be
  defect free
• The probability that a complete column of n
  elements will be defect free
• The probability that m of the ms columns in the
  array are defect free
• is the probability that there are sufficient
  elements to make the array completely operational

2
Impact of Redundancy on Yield

• If the control unit has an area of the
  probability of the control circuitry being defect
  free is
• The probability that a completely functional
  array is produced

3
Impact of Redundancy on Yield

• Example 4 x 4 array with two spare columns

4
Impact of Redundancy on Yield

• The yield of the circuit can be calculated as
• The yield of the nonredundant circuit

5
Impact of Redundancy on Yield

• The yield improvement is

6
Impact of Redundancy on Yield