Testing stacked devices

1. An electronically controlled method performed by a computerized testing system, said method comprising:

accessing a primary circuit assembly from a first circuit assembly carrier;

placing said primary circuit assembly into a test fixture;

accessing a secondary circuit assembly from a second circuit assembly carrier via a pick and place apparatus;

placing said secondary circuit assembly into said test fixture on top of said primary circuit assembly via said pick and place apparatus,

wherein said pick and place apparatus maintains contact with said secondary circuit assembly during and after said placing, and applies a force to said secondary circuit assembly sufficient for said secondary circuit assembly to electrically couple to said primary circuit assembly; and

testing said primary circuit assembly in conjunction with said secondary circuit assembly while coupled together while said pick and place apparatus applies said force.

2. The method of claim 1 wherein said force is sufficient for said primary circuit assembly to electrically couple to said test fixture.

3. The method of claim 1 further comprising:

removing said primary circuit assembly from said test fixture; and

placing said primary circuit assembly in a retainer according to results of said testing.

4. The method of claim 3 wherein said retainer is separate from said first circuit assembly carrier.

5. The method of claim 1 further comprising:

removing said secondary circuit assembly from said test fixture; and

placing said secondary circuit assembly in a retainer according to results of said testing.

6. The method of claim 1 wherein said secondary circuit assembly is retained by a removal mechanism for testing with a different instance of a primary circuit assembly.

7. A computer controlled method performed by a testing system, said method comprising:

accessing a primary circuit assembly from a first circuit assembly carrier by a first pick and place arm;

placing said primary circuit assembly into a test fixture by said first pick and place arm;

accessing a secondary circuit assembly from a second circuit assembly carrier by a second pick and place arm;

placing said secondary circuit assembly into said test fixture on top of said primary circuit assembly by said second pick and place arm

wherein said placing said secondary circuit assembly comprises said second pick and place arm maintaining contact with and applying force to said secondary circuit assembly sufficient for said secondary circuit assembly to electrically couple to said primary circuit assembly; and

testing said primary circuit assembly in conjunction with said secondary circuit assembly while coupled together.

8. The method of claim 7 wherein said force is sufficient for said primary circuit assembly to electrically couple to said test fixture.

9. The method of claim 7 further comprising:

removing said primary circuit assembly from said test fixture via said first pick and place arm; and

placing said primary circuit assembly in a retainer according to results of said testing.

10. The method of claim 9 wherein said retainer is separate from said first circuit assembly carrier.

11. The method of claim 7 further comprising:

removing said secondary circuit assembly from said test fixture via said second pick and place arm; and

placing said secondary circuit assembly in a retainer according to results of said testing.

12. The method of claim 7 wherein said secondary circuit assembly is retained by said second pick and place arm for testing with a different instance of a primary circuit assembly.

13. An apparatus comprising:

a test fixture configured to retain an integrated circuit assembly during testing,

wherein said integrated circuit assembly comprises an integrated circuit package;

first and second circuit assembly carriers for holding at least two different designs of integrated circuit;

a first pick and place arm configured for moving a first integrated circuit assembly between said test fixture and said first circuit assembly carrier;

a second pick and place arm configured for moving a second integrated circuit assembly between said test fixture and said second circuit assembly carrier, and

wherein said second pick and place arm is configured for applying force to said second integrated circuit assembly sufficient for said second integrated circuit assembly to make electrical contact with said first integrated circuit assembly, and for said first integrated circuit assembly to make electrical contact with contact of said test fixture.

14. The apparatus of claim 13 wherein said integrated circuit package is configured to be part of a Package on Package.

15. The apparatus of claim 13 wherein said second pick and place arm is configured to retain said second integrated circuit assembly after testing of said first and second integrated circuit assemblies, and to place said second integrated circuit assembly onto another instance of said first integrated circuit assembly.