Method for detecting and monitoring wafer probing process instability

• US 7,230,439 B2
• Filed: 02/05/2003
• Issued: 06/12/2007
• Est. Priority Date: 02/05/2003
• Status: Expired due to Fees

• Current Assignee: Systems On Silicon Manufacturing Company Pte Limited (NXP Semiconductors NV)
• Original Assignee: Systems On Silicon Manufacturing Company Pte Limited (NXP Semiconductors NV)
• Inventors: Tan, Beng Ghee
• Primary Examiner(s): Nguyen; Ha Tran
• Assistant Examiner(s): Velez; Roberto
• Application Number:
  US10/542,873
• Publication Number:
  US 20060149505A1
• Time in Patent Office: 1,588 Days
• Field of Search: 324754-762, 324/601, 324/158.1, 702 81- 84, 702/185
• US Class Current: 324/750.01
• CPC Class Codes: G01R 1/067 Measuring probes

Abstract

A system and method for detecting and monitoring wafer probe stability including the steps of, probing each die on a wafer, and for each die determining whether the result of the probe is a pass or a fail. If the result of a probe is a fail, re-probing the die and determining whether the re-probe is a pass or a fail. Once all the dies have been probed determining the rate of die re-probes that lead to passes, comparing the rate of passes on re-probes to a pre-determined limit, and if the rate of passes on re-probes is greater than the predetermined limit, assigning the probe status as unstable.

Claims

1. A method for detecting and monitoring wafer probe stability including the steps of:

probing each die on a wafer;

for each die determining whether the result of the probe is a pass or a fail;

if the result of a probe is a fail, re-probing the die and determining whether the re-probe is a pass or a fail;

once all the dies have been probed determining the rate of die re-probes that lead to passes;

comparing the rate of passes on re-probes to a pre-determined limit;

if the rate of passes on re-probes is greater than the predetermined limit, assigning the probe status as unstable; and

reporting the unstable probe status to another device.

2. A method for detecting and monitoring wafer probe stability as claimed in claim 1 wherein the step of reporting the probe status as unstable includes setting a flag on the monitoring device.

3. A method for detecting and monitoring wafer probe stability as claimed in claim 2 wherein the step of reporting the probe status as unstable further includes sounding an alarm and/or providing an indicator on a monitor.

4. A method for detecting and monitoring wafer probe stability as claimed in claim 2 wherein the step of assigning the probe status to unstable further includes disabling the probe equipment.

5. A method for detecting and monitoring wafer probe stability as claimed in claim 3 wherein the step of assigning the probe status to unstable further includes disabling the probe equipment.

6. A method for detecting and monitoring wafer probe stability as claimed in claim 1 wherein the step of re-probing any die that fails on the first probe is preformed a predetermined number of times.

7. A method for detecting and monitoring wafer probe stability as claimed in claim 6 wherein re-probing is preformed only once for each die that fails on the first probe.

8. A method for detecting and monitoring wafer probe stability as claimed in claim 6 wherein the step of re-probing may be performed more than once.

9. A method for detecting and monitoring wafer probe stability as claimed in claim 1 further including the step of creating a probe reference file for each wafer.

10. A method for detecting and monitoring wafer probe stability as claimed in claim 9 wherein the probe reference file contains a re-probe limit, re-probe recovery rate information, a bin re-probe limit, a sensitivity limit and the recovery rate for re-probing.

11. A method for detecting and monitoring wafer probe stability as claimed in claim 10 wherein the re-probe recovery rate information includes a limit value.

12. A method for detecting and monitoring wafer probe stability as claimed in claim 11 wherein for wafers with more than a few hundred dice the limit is 2%.

13. A method for detecting and monitoring wafer probe stability as claimed in claim 11 wherein the re-probe rate recovery limit is set as three times the standard deviation of the re-probe recovery rate from previously supplied data.

14. A method for detecting and monitoring wafer probe stability as claimed in claim 10 wherein the sensitivity limit includes data on the number of sensitive dies expected in a wafer.

15. A method for detecting and monitoring wafer probe stability as claimed in claim 10 wherein the recovery rate for re-probing is determined as:

$\frac{\begin{array}{c}(\mathrm{number}<br><br><br><br>\mathrm{of}<br><br><br><br>\mathrm{recover}<br><br><br><br>\mathrm{from}<br><br><br><br>\mathrm{fail}<br><br><br><br>\mathrm{to}<br><br><br><br>\mathrm{good}-\\ \mathrm{recovery}<br><br><br><br>\mathrm{from}<br><br><br><br>\mathrm{sensitivity}<br><br><br><br>\mathrm{limit}<br><br><br><br>\mathrm{to}<br><br><br><br>\mathrm{good})\end{array}}{\left(\mathrm{total}<br><br><br><br>\mathrm{number}<br><br><br><br>\mathrm{of}<br><br><br><br>\mathrm{tested}<br><br><br><br>\mathrm{good}<br><br><br><br>\mathrm{die}\right)}.$

16. A method for detecting and monitoring wafer probe stability as claimed in claim 9 wherein the method further includes the step of generating a report from the probe reference file for each completed wafer test.

17. A method for detecting and monitoring wafer probe stability as claimed in claim 16 wherein the report includes device identification information and fail to good probe information.

18. A system for detecting and monitoring wafer probe stability comprising:

means for probing each die on a wafer;

means for determining whether the result of the probe is a pass or a fail for each die;

means for re-probing the die if the result of a probe is a fail and means for determining whether the re-probe is a pass or a fail;

means for determining the rate of die re-probes that lead to passes once all the dies have been probed;

means for comparing the rate of passes on re-probes to a pre-determined limit; and

means for assigning the probe status as unstable if the rate of passes on re-probes is greater than the predetermined limit.