AUTOMATIC RETEST METHOD FOR SYSTEM-LEVEL IC TEST EQUIPMENT AND IC TEST EQUIPMENT USING SAME

• US 20150066414A1
• Filed: 04/25/2014
• Published: 03/05/2015
• Est. Priority Date: 08/30/2013
• Status: Abandoned Application

• Current Assignee: Chroma ATE Incorporated
• Original Assignee: Chroma ATE Incorporated
• Inventors: Ouyang, Chin-Yi, Hsu, Liang-Yu
• Application Number:
  US14/261,427
• Publication Number:
  US 20150066414A1
• Time in Patent Office: Days
• US Class Current: 702/117
• CPC Class Codes: G01R 31/287 Procedures; Software aspects
• CPC Class Codes: G01R 31/2894 Aspects of quality control [QC] G01R31/31718 takes precedence; program control for QC G05B19/41875

Abstract

An automatic retest method for a system-level IC test equipment and the IC test equipment is disclosed, wherein the IC test equipment includes multiple testing units, a loading/unloading unit, and a processing unit; each testing unit is capable of testing an IC individually and has a pass rate. When the testing unit finishes a test operation, it will send test report of the IC to the processing unit. The processing unit will determine whether the IC has reached a pass threshold of the testing unit. The processing unit will issue a command, according to a predetermined rule, to transfer the IC that failed to reach the pass threshold to one of the testing units conforming to the predetermined rule to conduct a retest operation. Finally, the processing unit will confirm whether the IC that failed to reach the pass threshold has reached the pass threshold in the retest operation.

Claims

1. A method of testing IC chips for a system-level IC test equipment that includes a processing unit, a loading/unloading unit, and multiple testing units adapted for testing the IC chips independently, wherein each of the testing units provides a pass rate for IC chips, the method comprising the steps of:

(a) using the testing units to test the IC chips individually and transmitting a test result of the IC chips to the processing unit;

(b) using the processing unit to assess whether the respective IC chips have reached pass thresholds of the respective testing units, according to the test result;

(c) according to a predetermined rule and under control of the processing unit, transferring the IC that failed to reach the pass threshold to one of the multiple testing units that conforms to the predetermined rule to conduct a retest operation, wherein the predetermined rule is set based on the pass rates of the multiple testing units; and

(d) assessing whether the IC that failed to reach the pass threshold in step (b) has reached the pass threshold in the retest operation.

2. The method of claim 1, further comprising, before the step (a), a step (e) of setting the predetermined rule, wherein the predetermined rule is set to select a testing unit having a highest pass rate from the testing units to conduct the retest operation for the IC which fails to reach the pass threshold in step (b).

3. The method of claim 1, further comprising, before the step (a), a step (f) of setting the predetermined rule, wherein the predetermined rule is set to immediately select the corresponding testing unit originally used for testing the IC which fails to reach the pass threshold in step (b) to conduct the retest operation for the IC in step (c).

4. The method of claim 1, further comprising, before the step (a), a step (g) of setting the predetermined rule, wherein the predetermined rule is set to select a testing unit from the testing units that have reached a predetermined level of pass rate to conduct a retest operation for the IC which fails to reach the pass threshold in step (b).

5. The method of claim 4, wherein the predetermined rule is further set to comprise excluding the corresponding testing unit originally used for testing the IC which fails to reach the pass threshold in step (b) from being selected for the retest operation for the IC in step (c).

6. The method of claim 1, further comprising, before the step (a), a step (h) of setting the predetermined rule, wherein the predetermined rule is set to select a testing unit from the upper half of the multiple testing units that have greater pass rates as compared with the lower half of the multiple testing units to conduct the retest operation for the IC in step (c).

7. The method of claim 6, wherein the predetermined rule is further set to comprise excluding the corresponding testing unit originally used for testing the IC which fails to reach the pass threshold in step (b) from being selected for the retest operation for the IC in step (c).

8. A system-level IC test equipment for testing a plurality of IC chips, comprising:

multiple testing units adapted for testing the IC chips independently;

a loading/unloading unit for picking up one of the IC chips and transferring it to a corresponding one of the multiple testing units where the IC chip is subjected to a test operation and taking the IC chip away from the corresponding testing unit after the test operation is finished; and

a processing unit for receiving a test result from the corresponding testing unit and giving a command, according to a predetermined rule, to transfer anyone of the IC chips that failed to reach a pass threshold to one of the multiple testing units that conforms to the predetermined rule to conduct a retest operation.

9. The system-level IC test equipment of claim 8, wherein the loading/unloading unit comprises multiple shuttles corresponding to the multiple testing units for accommodating the ICs under test.

10. The system-level IC test equipment of claim 8, wherein the processing unit comprises a memory device that stores the predetermined rule.