Method and apparatus for yield and failure analysis in the manufacturing of semiconductors

• US 6,477,685 B1
• Filed: 09/22/2000
• Issued: 11/05/2002
• Est. Priority Date: 09/22/1999
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Lovelace, Jerome R.
• Primary Examiner(s): Siek, Vuthe
• Assistant Examiner(s): TAT, BINH C
• Application Number:
  US09/668,566
• Time in Patent Office: 774 Days
• Field of Search: 716/4, 716/5, 716/6, 716/18-21, 438/12, 438/1, 438/18
• US Class Current: 716/56
• CPC Class Codes: H01L 22/20 Sequence of activities consisting of a plurality of measurements, corrections, marking or sorting steps

Abstract

A yield and failure analysis system having composite wafermaps provides the ability to view numerous lots on a single screen, identifying the semiconductor manufacturing process, which caused wafer failures and the associated malfunctioning equipment. A wafer inspection instrumentation (28) probes each wafer within a given lot and applies a series of tests. Wafer defect data is stored in a first relational database (46) for compiling a composite wafermap for each lot. Collected wafer defect data is converted into a FFT signature. Present wafer defect data is compared with stored converted wafer defect data patterns to generate correlation coefficients. When the correlation coefficients are within a predetermined range, the converted wafer defect data pattern is stored in the second relational database (47). Data may be accessed from both databases by a user interface (44), enabling the user to analyze data in real time and generate reports.

Claims

1. An automated wafer yield and failure analysis system, comprising:

a wafer inspection instrument;

a data collection means coupled to said wafer inspection instrument for collecting wafer defect data from multiple defects on wafers from said wafer inspection instrument, said wafer defect data includes x, y and z coordinates;

a central database system having a means for storing wafer defect data coupled to receive said wafer defect data to compile a composite wafermap for each lot;

a conversion means coupled to the wafer inspection instrument for converting the collected wafer defect data from the wafer inspection instrument from an instrument specific format to a standard format, said conversion means uses a plurality of Fast Fourier Transform equations to convert the defect data;

said central database system having a means for storing converted wafer defect data patterns coupled to receive said converted wafer defect data patterns, wherein the stored converted wafer defect data patterns are retrievable based on selected criteria;

a means for comparing present wafer defect data to said stored converted wafer defect data patterns to generate correlation coefficients coupled to receive said wafer defect data and said stored converted wafer defect data, wherein the correlation coefficients identify the process associated with the die failure;

said converted wafer defect data pattern is stored in said central database system when correlation coefficients are within a predetermined range; and

at least one user interface workstation wherein user selected converted wafer defect data can be analyzed in real time to identify the associated malfunctioning equipment.

2. The system as in claim 1, wherein said first central database system comprises:

a server;

a first relational database installed on said server for organizing said composite wafer defect data in tables wherein said wafer defect data is summed for a wafer-lot;

a second relational database installed on said server for organizing said converted wafer defect data in tables;

a third relational data base installed on said server for organizing said converted wafer defect data patterns when said correlation coefficients are within a predetermined range; and

wherein said means for storing composite wafer defect data and converted wafer defect data comprises a memory associated with said server to store said composite wafer defect data, said converted wafer defect data, and said tables.

3. The system as in claim 2, wherein said at least one interface workstation includes:

means for creating statistical graphical representations from said user selected composite wafer defect data; and

means for displaying said representations coupled to receive said statistical graphical representations.

4. The system as in claim 1, further comprising:

a second central database system including,

a server,

a relational database installed on said server for organizing said converted wafer defect data in tables wherein said converted wafer defect data is tagged according to preselected criteria, and

wherein said means for composite wafer defect data comprises a memory associated with said server to store said composite wafer defect data and said tables.

5. The system as in claim 4, wherein said at least one interface workstation includes:

means for creating statistical graphical representations from said user selected converted wafer defect data; and

means for displaying said representations coupled to receive said statistical graphical representations.

6. The system as in claim 3, further comprising:

at least one data analysis station having a means for analyzing said composite wafer defect data coupled to receive said user selected composite wafer defect data to analyze said composite wafer defect data;

a third central database system having means for storing composite wafer defect data pattern and analyzed composite wafer defect data coupled to receive said composite wafer defect data pattern and analyzed composite wafer defect data, wherein the stored composite wafer defect data patterns and analyzed composite wafer defect data are retrievable based on selected criteria;

a second conversion means coupled to the third central database system for converting the collected wafer defect data stored in the third central database system from an instrument specific format to a standard format, said second conversion means uses Fast Fourier Transform equations to convert said wafer defect data; and

a means for transferring said composite wafer defect data pattern and said analyzed wafer defect data to said second central database system.

7. The system as in claim 6, wherein said at least one data analysis station includes a means for creating statistical and graphical representations.

8. The system as in claim 7, wherein said means for creating said statistical and graphical representations is independent of said third central database system.

9. The system as in claim 8, wherein said means for creating said statistical and graphical representations includes a point-and-click graphical interface system allowing said user selected analyzed data to be selectively displayed in at least one format selected from the group consisting of a trend chart, an image, a wafer map, a tool comparison, or a Pareto chart.

10. The system as in claim 1, wherein said selected criteria includes process technology, layer, lot, wafer, device, process equipment identification, and scan tool identification.

11. A method for generating failure and yield analysis for composite wafermaps, comprising the steps of:

collecting wafer defect data from multiple defects on wafers from a wafer inspection instrument;

storing the wafer defect data from the wafer inspection instrument in a first central database system to form composite wafermaps for each lot;

converting wafer defect data into Fast Fourier Transform signatures;

storing the converted wafer defect data from the wafer inspection instrument in a second central database;

comparing wafer defect data with data previously stored in said second central database;

generating correlation coefficients from the comparison of present wafer defect data to past wafer defect data, wherein the correlation coefficients identify the process associated with the die failure;

transferring wafer defect data on to at least one user interface workstation;

analyzing wafer defect data to identify the associated malfunctioning equipment; and

displaying wafer defect data on to at least one user interface workstation.

12. The method of claim 11, further comprising the step of organizing said composite wafer defect data in tables in a relational database installed on a server in said first central database system wherein said composite wafer defect data is tagged according to preselected criteria comprising process technology, layer, lot, wafer, device process equipment identification, and scan tool identification.

13. The method of claim 12, further comprising the steps of creating statistical and graphical representations from said user selected composite wafer defect data;

and

displaying said representations at said user interface workstation in a format selected from the group consisting of a trend chart, an image, a wafer map, a tool comparison, or a pareto chart.