Method for analyzing wafer test parameters
First Claim
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;
performing a first searching step to determine which item of sample test items, in-line QC items and process step items is related to the wafer test item of each residual lot in the low yield group from the database;
when the sample test item is determined to be related to the wafer test item in the first searching step, obtaining a second standard value within a second range by analyzing the parameters related to the sample test item of the wafers in the high yield group;
performing a second comparison step to compare the parameters of sample test item of each residual lot in the low yield group with the second standard value and delete lot numbers of residual lots with parameters related to the sample test item within the second range;
determining a second amount of residual lots in the low yield group after the second comparison step;
while the second amount of residual lots in the low yield group is not equal to zero, performing the following steps;
a second searching step to determine which item of the in-line QC items and the manufacturing machine items is related to the sample test item of each residual lot from the low yield group in the database;
when the in-line QC item is determined to be related to the sample test item in the second searching step, obtaining a third standard value within a third range by analyzing the parameters related to the in-line QC item of the wafers in the high yield group;
performing a third comparison step to compare the parameters of in-line QC item of each residual lot in the low yield group with the third standard value and delete lot numbers of residual lots with the parameters related to the in-line QC item within the third range;
determining a third amount of residual lots in the low yield group after the third comparison step;
while the third amount of residual lots in the low yield group is not equal to zero, performing the following steps;
performing a third searching step to determine the process step item related to the in-line QC item of each residual lot in the low yield group in the database;
when the process step item is determined to be related to the in-line QC item in the third searching step, searching for manufacturing machines utilized for the production of the wafers in the high yield group at the process step;
searching for manufacturing machines utilized for the production of the residual lots of wafers in the low yield group at the process step; and
performing a determining process to determine manufacturing machines utilized for producing more wafers included in the residual lots in the low yield group than wafers in the high yield group; and
while the third amount of residual lots in the low yield group is equal to zero, stopping performing the third searching step; and
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.
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Accused Products
Abstract
A plurality of lots of wafers, each lot of wafers having a lot number and each wafer of each lot having at least one test parameter generated by performing at least one wafer test item stored in a database, are divided into a high yield group and a low yield group. By analyzing the wafer test parameters of the wafers in the high yield group, a first standard value within a first range is obtained. A first comparison step is then performed 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. Finally, a first amount of residual lots in the low yield group is determined. In response to the first amount of residual lots in the low yield group not equaling to zero, a first searching step is performed to which item of sample test items, in-line QC items and process step items is related to the wafer test item of each residual lot in the low yield group in the database.
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Citations
32 Claims
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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:
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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; performing a first searching step to determine which item of sample test items, in-line QC items and process step items is related to the wafer test item of each residual lot in the low yield group from the database; when the sample test item is determined to be related to the wafer test item in the first searching step, obtaining a second standard value within a second range by analyzing the parameters related to the sample test item of the wafers in the high yield group; performing a second comparison step to compare the parameters of sample test item of each residual lot in the low yield group with the second standard value and delete lot numbers of residual lots with parameters related to the sample test item within the second range; determining a second amount of residual lots in the low yield group after the second comparison step; while the second amount of residual lots in the low yield group is not equal to zero, performing the following steps; a second searching step to determine which item of the in-line QC items and the manufacturing machine items is related to the sample test item of each residual lot from the low yield group in the database; when the in-line QC item is determined to be related to the sample test item in the second searching step, obtaining a third standard value within a third range by analyzing the parameters related to the in-line QC item of the wafers in the high yield group; performing a third comparison step to compare the parameters of in-line QC item of each residual lot in the low yield group with the third standard value and delete lot numbers of residual lots with the parameters related to the in-line QC item within the third range; determining a third amount of residual lots in the low yield group after the third comparison step; while the third amount of residual lots in the low yield group is not equal to zero, performing the following steps; performing a third searching step to determine the process step item related to the in-line QC item of each residual lot in the low yield group in the database; when the process step item is determined to be related to the in-line QC item in the third searching step, searching for manufacturing machines utilized for the production of the wafers in the high yield group at the process step; searching for manufacturing machines utilized for the production of the residual lots of wafers in the low yield group at the process step; and performing a determining process to determine manufacturing machines utilized for producing more wafers included in the residual lots in the low yield group than wafers in the high yield group; and while the third amount of residual lots in the low yield group is equal to zero, stopping performing the third searching step; and 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. - View Dependent Claims (2)
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3. 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, the wafer test item comprising a plurality of electrical tests performed on each die of each wafer, the wafer test parameters comprising statistic results of the electrical tests, 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:
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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; searching for parameters of the electrical tests performed on each die of each wafer in the low yield group to define dies failing in the electrical tests as target dies and obtain a distribution chart of target dies of each wafer; comparing the distribution chart of target dies of each wafer with a distribution chart of the wafer test parameters of the corresponding wafer to obtain an overlapping ratio; marking wafers with the overlapping ratio greater than an second standard value as target wafers; selecting lot numbers of lots comprising an amount of target wafers greater than a third standard value; and determining which item of the sample test items and the process step items is related to the wafer test item of each residual lot in the low yield group in the database; and while the first amount of residual lots in the low yield group is equal to zero, stopping searching. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. 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:
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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; performing a first searching step to determine which item of sample test items, in-line QC items and process step items is related to the wafer test item of each residual lot in the low yield group from the database; when the in-line QC item is determined to be related to the wafer test item in the first searching step, obtaining the third standard value within the third range by analyzing the parameters related to the in-line QC item of the wafers in the high yield group; performing the third comparison step to compare the parameters of in-line QC item of each residual lot in the low yield group with the third standard value and delete lot numbers of residual lots with the parameters related to the in-line QC item within the third range; determining the third amount of residual lots in the low yield group after the third comparison step; while the third amount of residual lots in the low yield group is not equal to zero, performing the following steps; performing the third searching step to determine which item of the process step items is related to the in-line QC item of each residual lot in the low yield group in the database; when the process step item is determined to be related to the in-line QC item in the third searching step, searching for manufacturing machines utilized for the production of the wafers in the high yield group at the process step; searching for manufacturing machines utilized for the production of the residual lots of wafers in the low yield group at the process step; and performing a determining process to determine manufacturing machines utilized for producing more wafers included in the residual lots in the low yield group than wafers in the high yield group; and while the third amount of residual lots in the low yield group is equal to zero, stopping performing the third 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. - View Dependent Claims (20)
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21. 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:
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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; performing a first searching step to determine which item of sample test items, in-line QC items and process step items is related to the wafer test item of each residual lot in the low yield group from the database; when the process step item is determined to be related to the wafer test item in the first searching step, performing the following steps; searching for manufacturing machines utilized for the production of the wafers in the high yield group at the process step; searching for manufacturing machines utilized for the production of the residual lots of wafers in the low yield group at the process step; and performing a determining process to determine manufacturing machines utilized for producing more wafers included in the residual lots in the low yield group than wafers in the high yield group; and while the first amount of residual lots in the low yield group is equal to zero, stopping performing the first searching step. - View Dependent Claims (22)
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23. 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:
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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; performing a first searching step to determine which item of sample test items, in-line QC items and process step items is related to the wafer test item of each residual lot in the low yield group from the database; when the first amount of residual lots in the low yield group is determined not to be zero, determining defects on wafers in the residual lots in the low yield group and recording lot numbers of lots comprising wafers with defects; making a distribution chart of defects in a plurality of layers on each wafer with defects in each lot; making a distribution chart of the wafer test parameters of each wafer with defects; comparing the distribution chart of defects for the plurality of layers with the distribution chart of wafer test parameters of each wafer with defects to obtain an overlapping ratio of the distribution chart of defects in the plurality of layers to the distribution chart of wafer test parameters of each wafer with defects and finding out at least one target layer with a high overlapping ratio; and searching the database for the process step item related to the target layer; and while the first amount of residual lots in the low yield group is equal to zero, stopping performing the first searching step. - View Dependent Claims (24, 25, 26, 27)
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28. 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:
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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; performing a first searching step to determine which item of sample test items, in-line QC items and process step items is related to the wafer test item of each residual lot in the low yield group from the database; when the first amount of residual lots in the low yield group is determined not to be zero, determining defects on wafers in the residual lots in the low yield group and recording lot numbers of lots comprising wafers with defects; making a distribution chart of defects in each layer on each wafer with defects in each lot; calculating the defects in each layer on each wafer with defects in each lot; analyzing a distribution chart of the wafer test parameters of each wafer with defects; comparing the distribution chart of defects in each layer with the distribution chart of wafer test parameters of each wafer with defects to obtain an overlapping ratio of the distribution chart of defects in each layer to the distribution chart of wafer test parameters of each wafer with defects; calculating a defect ratio of the number of defects in each layer on each wafer to the number of dies with wafer test parameters not within the first range; determining the overlapping ratio; while the overlapping ratio is larger than or equal to a fifth standard value, performing the following steps; marking the layer as a first defective layer; determining the defect ratio; while the defect ratio is larger than or equal to a sixth standard value, performing the following steps; marking the layer as a second defective layer; searching for lot numbers of lots with wafers comprising at least one of either the first defective layer or the second defective layer; and searching the database for the process step item related to either the first defective layer or the second defective layer; and while the defect ratio is less than the sixth standard value, not marking the layer as the second defective layer; and while the overlapping ratio is less than the fifth standard value, not marking the layer as the first defective layer; and while the first amount of residual lots in the low yield group is equal to zero, stopping performing the first searching step. - View Dependent Claims (29, 30, 31, 32)
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Specification