Die sorting apparatus and method

• US 7,345,254 B2
• Filed: 12/08/2004
• Issued: 03/18/2008
• Est. Priority Date: 12/09/2003
• Status: Active Grant

• Current Assignee: ASM Assembly Automation Limited (ASMPT Ltd.)
• Original Assignee: ASM Assembly Automation Limited (ASMPT Ltd.)
• Inventors: Yang, Yang, Chau, Keung, Zhong, Wei Min, Loh, Choo Han
• Primary Examiner(s): Rodriguez; Joseph C.
• Application Number:
  US11/006,928
• Publication Number:
  US 20050130333A1
• Time in Patent Office: 1,196 Days
• Field of Search: 209571-574, 209/939, 700/121, 700/223, 382/145, 382/151
• US Class Current: 209/571
• CPC Class Codes: H01L 21/67271 Sorting devices

Abstract

A die sorting apparatus for a wafer is provided that associates logical positions of each die from a map file for storing records of testing information based upon testing performed on individual dice comprised in the wafer with its physical position as illustrated by an image acquired by an image capturing device showing physical positions of the dice, after the dice have been singulated. A processing device can thus determine actual physical positions of the dice for reference by a die pick-up device configured to selectively pick up dice that meet predetermined criteria according to the testing information from their actual physical positions as determined.

Claims

1. A die sorting apparatus for a wafer, comprising:

a map file for storing records of testing information based upon testing performed on individual dice in the wafer and relative logical positions of the dice;

an image capturing device operative to acquire an image of at least a portion of the wafer comprising at least two individual dice, wherein the image shows physical coordinates of the at least two individual dice after the dice have been singulated;

a processing device operative to associate the logical position of each of the individual dice from the map file with the physical coordinates of each of the at least two individual dice as calculated from the image of the wafer and to generate a data file based on the association of the logical position and the physical coordinates of each of the dice, the data file storing the actual physical coordinates and the relative logical positions of each of the dice comprised in the at least the portion of the wafer; and

a die pick-up device operative to selectively pick up dice that meet predetermined criteria according to the testing information from their actual physical positions as contained in the data file generated by the processing device.

2. The die sorting apparatus as claimed in claim 1, including a wafer sorter to which the wafer is transferable, wherein the die pick-up device is operable to remove the dice from the location of the wafer sorter.

3. The die sorting apparatus as claimed in claim 2, including a calibration system to calibrate the wafer sorter against the image by calibrating a resolution of the wafer sorter against actual physical coordinates of the dice for reference by the die pick-up device.

4. The die sorting apparatus as claimed in claim 1, including a display device operable to display the image and to superimpose on at least one die shown in the image testing information for the at least one die.

5. The die sorting apparatus as claimed in claim 4, including a reference die selector operable by an operator to select a reference die from the image prior to processing by the processing device for facilitating association of the logical positions of the dice with the physical coordinates of the dice.

6. The die sorting apparatus as claimed in claim 1, wherein the data file generated by the processing device is an output file comprising testing information of the dice and the actual physical coordinates of the dice referable by the die pick-up device.

7. The die sorting apparatus as claimed in claim 1, wherein the actual physical coordinates of each die includes information regarding an X coordinate, a Y coordinate and an angular displacement of each die.

8. The die sorting apparatus as claimed in claim 1, wherein the map file comprises testing information obtained from test probing of the individual dice in the wafer before the wafer is singulated.

9. The die sorting apparatus as claimed in claim 1, wherein the testing information comprises grades and/or electrical properties of the dice.

10. A method of sorting a wafer including singulated dice, comprising the steps of:

providing a map file containing records of testing information based upon testing performed on individual dice in the wafer and relative logical positions of the dice;

acquiring an image of at least a portion of the wafer comprising at least two individual dice after the dice have been singulated, the acquired image showing physical coordinates of the at least two individual singulated dice;

associating the logical positions of each of the individual dice from the map file with the physical coordinates of each of the at least two individual dice as calculated from the image;

generating a data file based on the association of the logical position and the physical coordinates of each of the dice, the data file storing the actual physical coordinates and the relative logical positions of each of the dice comprised in the at least the portion of the wafer; and

thereafter

selectively picking up dice that meet predetermined criteria according to the testing information from the actual physical coordinates contained in the data file.

11. The method as claimed in claim 10, further comprising a step of capturing an image of a slice of the wafer for learning a pattern of at least one die to recognize the pattern among the dice prior to acquiring the image of the whole wafer.

12. The method as claimed in claim 10, further comprising a step of displaying the image on a display device with testing information for at least one die superimposed onto a portion of the image showing the at least one die.

13. The method as claimed in claim 12, including a step of selecting a reference die from the image for facilitating association of the logical positions of the dice with the physical coordinates of the dice.

14. The method as claimed in claim 10, wherein the data file generated by the step of generating the data file comprises generating an output file comprising records of testing information of the dice and the respective physical coordinates referable by the die pick-up device.

15. The method as claimed in claim 10, wherein the actual physical coordinates of each die includes information regarding an X coordinate, a Y coordinate and an angular displacement of each die.

16. The method as claimed in claim 10, including a step of transferring the wafer to a wafer sorter prior to picking up dice with the die pick-up device.

17. The method as claimed in claim 16, further comprising a step of calibrating a mapping sorter against the image by calibrating a resolution of the mapping sorter against the actual physical coordinates of the dice.

18. The method as claimed in claim 10, wherein the map file comprises testing information obtained from test probing of the individual dice in the wafer before the wafer is singulated.

19. The method as claimed in claim 10, wherein the testing information comprises grades and/or electrical properties of the dice.