Method for analyzing in-line QC test parameters

A method for analyzing in-line QCtest parameters is used to analyze a plurality of lots of products, each lot of products having a lot number and being formed using a plurality of equipments. At least one wafer of each lot of products is tested by at least one in-line QC test item to generate an in-line QC test parameter. The in-line QC test item, a sample test item and a wafer test item related to the in-line QC test item are stored in a database. The database further stores the in-line QC test parameter and data of a plurality of lots of high-yield product stocks, such as various test items and test parameters. The method includes the following steps: analyzing the in-line QC test parameter to determine whether the in-line QC test parameter corresponds to a predetermined spec or not; searching the database to find out the sample test item or the wafer test item related to the in-line QC test item when the in-line QC test parameter does not correspond to the predetermined spec; searching the database to find out the corresponding test parameters of the high-yield product stocks according to the in-line QC test item and the searched sample test item or the wafer test item; and generating a correlation to illustrate the relationship between the in-line QC test item and the sample test item, or the relationship between the in-line QC test item and the wafer test item according to the searched high-yield product stocks.