Method and apparatus for characterizing a semiconductor device

• US 6,319,737 B1
• Filed: 08/10/1999
• Issued: 11/20/2001
• Est. Priority Date: 08/10/1999
• Status: Expired due to Term

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: Advanced Micro Devices, Inc.
• Inventors: Sun, Chin-Yang, Cheng, Jennifer Meng-Tzu, Putnam, Gary Gene
• Primary Examiner(s): Niebling, John F.
• Assistant Examiner(s): STEVENSON, ANDRE C
• Application Number:
  US09/371,498
• Time in Patent Office: 833 Days
• Field of Search: 118/719, 437/8, 257/773, 324/158.1, 438/17, 438/592, 438/622
• US Class Current: 438/17
• CPC Class Codes: G01R 31/2831 Testing of materials or semi-finished products, e.g. semiconductor wafers or substrates G01R31/318511 takes precedence; testing during manufacture H01L22/00
• CPC Class Codes: H01L 22/20 Sequence of activities consisting of a plurality of measurements, corrections, marking or sorting steps

Abstract

A method and apparatus are provided for providing characterization data for semiconductor devices. A first data set containing measured results obtained from wafer electrical tests performed on the semiconductor device during the fabrication process is compared to a second data set containing values corresponding to design characteristics for the semiconductor device. Based on this comparison, semiconductor devices having valid and invalid performance characteristics are identified. The characterization results data are subsequently generated for the identified semiconductor devices.

Claims

1. A computer-readable medium carrying one or more sequences of instructions for generating characterization data for a fabrication process in which semiconductor devices are formed upon at least one wafer, wherein execution of the one or more sequences of instructions by one or more processors causes the one or more processors to perform the steps of:

receiving a first data set containing measured results obtained from tests performed on the semiconductor devices during the fabrication process;

receiving a second data set containing values corresponding to design characteristics for the semiconductor devices;

comparing the measured results from the first data set to the design characteristics from the second data set;

identifying semiconductor devices having valid and invalid performance characteristics, based on the step of comparing; and

generating the characterization data for the fabrication process based on the identified valid semiconductor devices;

whereby the characterization data includes proposed limit parameters to which test results from said semiconductor devices will conform.

2. The computer-readable medium of claim 1, wherein the step of receiving a first data set further comprises the steps:

determining if split lots were used in the fabrication process to form the semiconductor devices;

receiving input, from a user, that identifies split lots to which each of the at least one wafer belongs; and

generating one or more process characteristics for each split lot, based on the received input.

3. The computer-readable medium of claim 2, wherein the step of generating one or more process characteristics further comprises the steps:

combining measured results for semiconductor devices formed on wafers belonging to a selected split lot;

determining a statistical mean for the combined measured results of the selected split lot; and

repeating the steps of combining and determining until all split lots have been identified.

4. The computer-readable medium of claim 1 wherein the one or more processors further perform the steps:

identifying a key test parameter;

determining net die per wafer value; and

creating scatter plot that displays the results of the key test parameter relative to test parameters from the first and second data set.

5. The computer-readable medium of claim 1, wherein the one or more processors further perform the steps:

receiving a third data set corresponding to measured results from a prescribed number of previously fabricated wafers; and

determining, based on the third data set, a current statistical mean and standard deviation of the measured results for the semiconductor devices on the at least one wafer.

6. The computer-readable medium of claim 1, wherein the step of receiving a first data set further comprises the steps:

receiving a test parameter from a user;

determining a statistical mean of the measured results corresponding to the received test parameter for each of the at least one wafer; and

determining minimum and maximum values of the measured results corresponding to the received test parameter for each of the at least one wafer.

7. The computer-readable medium of claim 1, wherein the step of receiving further comprises the step of determining a statistical mean of each measured result for each of the at least one wafer.

8. The computer-readable medium claim 1, wherein the step of receiving a first data set further comprises the steps:

receiving at least two selected test parameters from a user;

determining a statistical mean of the measured results corresponding to the two selected test parameters, for each of the at least one wafer;

determining minimum and maximum values of the measured results corresponding to the two selected test parameters, for each of the at least one wafer; and

determining a median and standard deviation of the measured results corresponding to the two selected test parameters, for each of the at least one wafer.

9. The computer-readable medium of claim 1, wherein the step of identifying semiconductor devices having valid and invalid performance characteristics further comprises the steps:

sequentially selecting a test parameter from test parameters used to obtain the measured results; and

for each test parameter selected, performing the steps;

identifying measured results, from the first data set, corresponding to a selected test parameter for the semiconductor devices,

identifying values, from the second data set, corresponding to design characteristic values for the selected test parameter,

comparing the measured results identified from the first data set to the values identified from the second data set, and

determining, based on the step of comparing the values, semiconductor devices that have measured results which do not conform to the design characteristics.

10. The computer-readable medium of claim 1, wherein the step of identifying semiconductor devices having valid performance characteristics further comprises the steps:

identifying values, from the first data set, corresponding to a voltage transition parameter that is measured from the semiconductor devices;

identifying values, from the second data set, corresponding to design characteristic values for voltage transition;

comparing the values identified from the first data set to the values identified from the second data set; and

determining, based on the step of comparing the values, semiconductor devices that do not transition between a first state and a second state.

11. The computer-readable medium of claim 1, wherein the step of identifying semiconductor devices having valid and invalid performance characteristics further comprises the steps:

comparing measured results for each test parameter from the first data set to corresponding values from the selected data limits; and

identifying semiconductor devices having measured results that fall outside a prescribed range of values.

12. The computer-readable medium of claim 11, wherein the one or more processors further perform a step of identifying devices whose test results produce abnormal values.

13. The computer-readable medium of claim 1, wherein the one or more processors further perform the steps:

determining a percentage of identified semiconductor devices that have invalid performance characteristics; and

if the determined percentage value exceeds a predetermined threshold, then outputting a warning.

14. The computer-readable medium of claim 1, wherein the step of identifying further includes the step of removing, by a user, individual semiconductor devices that have measured results considered to be invalid.

15. The computer-readable medium of claim 1, wherein the step of generating further includes the steps:

selecting semiconductor devices having marginal performance characteristics; and

determining a change for measured results for the semiconductor devices at different temperatures.

16. The computer-readable medium of claim 1, wherein the step of receiving the first data set includes the step of receiving the first data set from a remote location through the Internet, using a web browser interface.

17. The computer-readable medium of claim 1, wherein the step of receiving a second data set includes the step of receiving the second data set from a remote location through the Internet, using a web browser interface.

18. A system for generating characterization data for a fabrication process comprising:

a workstation configured to;

access a first data set containing measured results obtained from tests performed on said semiconductor devices during said fabrication process,

access a second data set containing values corresponding to design characteristics for said semiconductor devices,

compare the measured results from said first data set to the design characteristics from said second data set to thereby identify semiconductor devices having valid and invalid performance characteristics, and

generate said characterization data for the fabrication process based on the identified valid semiconductor devices,

whereby said characterization data includes proposed limit parameters to which test results from said semiconductor devices will conform; and

a display operatively coupled to said workstation for displaying said characterization data.

19. The system of claim 18, further comprising a second workstation for storing said first and second data sets, said first workstation is further configured to execute a web browser for providing a communication platform for accessing said first and second data sets via the a packet data network.

20. The system of claim 18, wherein, upon accessing said first data set, said workstation is further configured to:

receiving a test parameter from a user;

determining a statistical mean of the measured results corresponding to the received test parameter for each of the at least one wafer; and

determining minimum and maximum values of the measured results corresponding to the received test parameter for each of the at least one wafer.

21. The system of claim 18, wherein said first and second data sets are stored on a computer-readable medium.

22. The system of claim 18, wherein said workstation is further configured to identify said semiconductor devices having valid and invalid performance characteristics by performing the steps:

sequentially selecting a test parameter from test parameters used to obtain the measured results; and

for each test parameter selected, performing the steps;

identifying measured results, from the first data set, corresponding to a selected test parameter for the semiconductor devices,

identifying values, from the second data set, corresponding to design characteristic values for the selected test parameter,

comparing the measured results identified from the first data set to the values identified from the second data set, and

determining, based on the step of comparing the values, semiconductor devices that have measured results which do not conform to the design characteristics.