Partial wafer processing for random size wafers

• US 20030224552A1
• Filed: 06/03/2002
• Published: 12/04/2003
• Est. Priority Date: 06/03/2002
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Subramanian, Balamurugan
• Granted Patent: US 7,015,068 B2
• Time in Patent Office: Days
• US Class Current: 438/106
• CPC Class Codes: H01L 2223/54453 for use prior to dicing
• CPC Class Codes: H01L 2223/54466 Located in a dummy or reference die
• CPC Class Codes: H01L 23/544 Marks applied to semiconductor devices or parts, e.g. registration marks, alignment structures, wafer maps test patterns for characterising or monitoring manufacturing processes H01L22/00
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A method of processing a partial wafer in accordance with one embodiment comprises includes after of loading partial wafer into wafer table of pick and place equipment after saw; downloading wafer map data for the wafer from wafer map data host. If the partial wafer has a reference die then positioning the wafer table to the reference die and then moving the wafer table to the last column of the partial wafer. If the partial wafer does not have a reference die the last column (LCOLUMN) information is obtained from wafer map data header field in one embodiment and using LCOLUMN information remove all dies in the right side of partial wafer map. The wafer table is moved to pseudo reference die which is the first die in the bottom right. The pseudo reference die coordinate (x1, y1) is calculated where x1=first column from right to left that has a die in the wafer map data and y1=first bottom most row in the column x1 from the wafer map data. If this partial wafer is not the last partial wafer of this wafer, the wafer table is moved to the last left column (LCOLUMN) of the partial wafer. The LCOLUMN is set as complete if this is the last partial wafer and then the LCOLUMN is updated in the wafer map data header field in the original wafer map. The LCOLUMN information is used remove all dies from the wafer map data that are not part of this partial wafer. The LCOLUMN is updated in the wafer map data header field. The wafer map data file is saved for next partial wafer of the same wafer to process in the pick and place equipment and the then pick and place operation.

Claims

1. A method of processing partial wafers comprising the steps of:

making all partial wafer cuts perpendicular to the wafer flat with all partial wafer cuts following a cut sequence where the first cut section is with a reference die and the other cut sections are in the numerical order from right to left with the first partial wafer of the full wafer having a reference die

identifying a pseudo reference die for each partial wafer not having a reference die which die is the first die in the bottom right;

moving wafer table to the last left column of the partial wafer and determining the coordinate;

removing all dies from the wafer map that are not part of the partial wafer using said coordinate; and

performing picking and placing dies.

2. The method of claim 1 wherein said pseudo reference die is determined by die coordinate (x1,y1) where x1=first column from right to left that has a die in the wafermap data and y1=first bottom most row in the column x1 from the wafermap data or x1=first column from right to left that has a die in unpicked die bin of wafer map data and y1=first bottom most row in the column x1 in unpicked die bin of wafer map data.

3. The method of claim 2 wherein said last column number is placed in the header of the wafer map data file for the next partial wafer.

4. The method of claim 3 wherein the last column information is stored in the wafer map data file and the same wafer map data file is used for all partial wafers with different last column values.

5. The method of claim 1 including the step of assigning a new bin number to picked die and the picked die coordinates are stored and the last column information is used to find the edge and the picked die coordinates are stored in the wafer map data file and the same wafer map data file is used for all partial wafers and after a partial process is completed all the picked die coordinates are moved to the picked die bin.

6. The method of claim 1 wherein the last column and wafer identification information is stored in a separate file and wherein before processing a partial wafer getting the last column information from the storage.

7. The method of claim 1 wherein there is preprocessing on the partial wafer so that only partial wafer map data is available.

8. A method of processing one or more partial wafers comprising the steps of:

providing a wafer map data file containing a header identifying a full or partial wafer and identifying a starting column for processing the full or partial wafer and operating a wafer pick and place equipment to begin at the starting point location of the partial wafer identified by the header for wafer mapping operations to process the partial wafer for picking good dies.

9. A method of processing a partial wafer in pick and place equipment comprising the steps of:

loading partial wafer into wafer table of pick and place equipment after saw;

downloading wafer map data for the wafer from wafer map data host;

if the partial wafer has a reference die positioning the wafer table to the reference die and moving the wafer table to the last column of the partial wafer and removing all die not part of the partial wafer;

if the partial wafer does not have a reference die getting last column (LCOLUMN) information from wafer map data header field and using LCOLUMN information removing all dies in the right side of partial wafer, moving the wafer table to pseudo reference die which is the first die in the bottom right, computing the pseudo reference die coordinate (x1, y1) where x1=first column from right to left that has a die in the wafer map data and y1=first bottom most row in the column x1 from the wafer map data;

if this partial wafer is not the last partial wafer of this wafer moving the wafer table to the last left column (LCOLUMN) of the partial wafer and using LCOLUMN information removing all dies from the wafer map data that are not part of this partial wafer;

setting the LCOLUMN as complete if this is the last partial wafer;

updating the LCOLUMN in the wafer map data header field;

saving the wafer map data file for next partial wafer of the same wafer to process in the pick and place equipment or send the data to wafer map data host or other storage systems; and

performing pick and place operation.

10. A method of processing a partial wafer in pick and place equipment comprising the steps of:

loading partial wafer into wafer table of pick and place equipment after saw;

downloading wafer map data for the wafer from wafer map data host;

if the partial wafer has a reference die positioning wafer table to reference die and moving the wafer table to the last left column (LCOLUMN) of the partial and removing all dies that are not a part of the partial wafer,

if the partial wafer does not have a reference die moving the wafer table to the pseudo reference die which is the first die in the bottom right;

computing the pseudo reference die coordinate (x1, y1) where x1=first column from right to left that has a die in unpicked die bin of wafer map data and y1=first bottom most row in the column x1 in unpicked die bin of wafer map data;

if this partial wafer is the last partial wafer for this wafer then in the original wafer map, moving all the unpicked the coordinates in an unpicked die bin to picked die bin;

if this partial wafer is not the last partial wafer moving the wafer table to the left column of the partial wafer and determine the coordinate;

using LCOLUMN information removing all dies from the wafer map data that are not part of this partial wafer;

in the original wafer map, updating the picked die coordinates in the picked die bin;

saving the wafer map data file for next partial wafer of the same wafer to process and performing pick and place operation.

11. A method of processing a partial wafer in pick and place equipment comprising the steps of:

loading partial wafer into wafer table of pick and place equipment after saw;

downloading wafer map data for the wafer from wafer map data host;

if the partial wafer has reference die positioning wafer table to reference die, moving the wafer table to the last left column (LCOLUMN) of the partial wafer, determine coordinate and remove all dies that are not part of the partial wafer;

if the partial wafer does not have a reference die getting LCOLUMN information from pick and place equipment or wafer map data host or other storage systems;

using LCOLUMN information removing all dies in the right side of partial wafer;

. moving the wafer table to pseudo reference die which is the first die in the bottom right;

computing pseudo reference die coordinate (x1,y1) where x1=first column from right to left that has a die in the wafermap data and y1=first bottom most row in the column x1 from the wafermap data;

if this partial wafer is not the last partial wafer for this wafer moving the wafer table to the last left column (LCOLUMN) of the partial wafer and determining the coordinate and using the coordinate removing all dies from the wafer map that are not part of the partial wafer;

saving the LCOLUMN and wafer identification information for next partial wafer of the same wafer to process; and

processing pick and place operation.

12. A method of processing a partial wafer in pick and place equipment comprising the steps of:

getting wafer map data and last column information;

removing all dies from the wafer map in the right side of the partial wafer using last column information and saving the wafer map data for processing;

loading partial wafer into wafer table of pick and place equipment after saw;

downloading wafer map data for the wafer from wafer map data host;

if the partial wafer has reference die positioning wafer table to reference die, moving the wafer table to the last left column (LCOLUMN) of the partial wafer, determine coordinate and remove all dies that are not part of the partial wafer;

if the partial wafer does not have a reference die moving the wafer table to the pseudo reference die which is the first die in the bottom right;

computing the pseudo reference die coordinate;

if this partial wafer is the last partial wafer for this wafer then in the original wafer map, moving all the unpicked the coordinates in an unpicked die bin to picked die bin;

if this partial wafer is not the last partial wafer moving the wafer table to the left column of the partial wafer and determine the coordinate;

using LCOLUMN information removing all dies from the wafer map data that are not part of this partial wafer;

in the original wafer map, updating the picked die coordinates in the picked die bin;

saving the wafer map data file for next partial wafer of the same wafer to process and performing pick and place operation.

13. The method of claim 12 wherein said first removing step includes converting the wafer map data by moving all dies from unpicked die bin which has column coordinates less than or equal to the last column into picked die bin.

14. The method of claim 12 wherein said first removing step includes removing all dies in the map which has the column coordinate less than or equal to the last column.