Patent ID: 6968280
Filing Date: 2005-11-22
Classification: H01L

Abstract:
1. A method for analyzing wafer test parameters of a plurality of lots of wafers, each lot of the wafers comprising a lot number, each wafer of each lot comprising at least one wafer test parameter generated by performing at least one wafer test item stored in a database, parameters related to at least one sample test item, one in-line quality control (QC) item and one process step item related to the wafer test item being stored in the database, the method comprising: dividing the lots of wafers into at least a high yield group and a low yield group based on yield of the lots; obtaining a first standard value within a first range by analyzing the wafer test parameters of the wafers in the high yield group; performing a first comparison step to compare each wafer test parameter of each lot in the low yield group with the first standard value and delete lot numbers of lots with wafer test parameters within the first range; determining a first amount of residual lots in the low yield group after the first comparison step; while the first amount of residual lots in the low yield group is not equal to zero, performing the following steps: while the second amount of residual lots in the low yield group is not equal to zero, performing the following steps: while the second amount of residual lots in the low yield group is equal to zero, stopping performing the second searching step; and while the first amount of residual lots in the low yield group is equal to zero, stopping performing the first searching step.