System for testing multiple groups of IC-chips which concurrently sends time-shifted test signals to the groups
View Patent ↗An electromechanical system for testing IC-chips includes a total of N chip holding subassemblies; a moving mechanism for automatically moving the i-th chip holding subassembly from a load position in the system to the test position in the systems, and visa-versa, where i ranges from 1 to N and changes with time in a sequence; and a signal generator which sends test signals to the IC-chips at the test position. Between the moving of the i-th chip holding subassembly and the next subassembly in the sequence, test signals are sent to the IC-chips on all N of the chip holding subassemblies such that the signals are shifted in time from one subassembly to another. Also, while the i-th chip holding subassembly is being moved, the time shifted test signals continue to be sent to the IC-chips on the remaining N−1 chip holding subassemblies.
1. An electromechanical system for testing IC-chips; said system being comprised of:
a total of N chip holding subassemblies, where N is as integer greater than one and where each chip holding subassembly has sockets for holding a group of IC-modules that include said IC-chips;
a moving means for automatically moving the i-th one of said N chip holding subassemblies from a load position in said system to a test position in said system, and visa-versa, where i changes with time in a sequence;
a power supply means which sends electrical power only to those IC-modules that are held by said chip holding subassemblies at said test position; and,
a signal generator means which sends test signals concurrently to said IC-chips on all chip holding subassemblies that are at said test position, where said test signals are shifted in time from one subassembly to another.
2. A system according to claim 1 wherein said signal generator means begins to send said test signals to said IC-chips that are on the i-th chip holding subassembly, between the time that subassembly is moved to said test position and the time that the next chip holding subassembly in said sequence is moved to said test position.
3. A system according to claim 2 wherein said sequence in which said moving means moves said i-th chip holding subassembly in a repetitive sequence.
4. A system according to claim 2 wherein said sequence in which said moving means moves said i-th chip holding subassembly in a random sequence.
5. A system according to claim 2 wherein said moving means moves said i-th chip holding subassembly from said load position to said test position, and visa-versa, while at least half of said N chip holding subassemblies are at said test position.
6. A system according to claim 2 wherein said signal generator means includes N digital state machines, one on each of said N chip holding subassemblies, and a master controller which is stationary and is coupled via a communication channel to each of said N digital state machines.
7. A system according to claim 2 wherein said signal generator means sends test signals which place said IC-chips in a predetermined state but do not functionally test said IC-chips.
8. A system according to claim 2 wherein said signal generator means sends test signals which functionally test said IC-chips.
9. A system according to claim 2 which further includes a chip handler means, which is time-shared by all of said chip holding subassemblies, for moving said IC-modules from one source container into the sockets on said i-th chip holding subassembly at said load position, and from those sockets to at least one pass container and one fail container.
10. A system according to claim 9 which further includes a means for automatically replacing any one of said containers when chip handler means has emptied or filled that container with said IC-modules.
11. A system according to claim 9 wherein each socket on said chip holding subassembly faces downward at said load and test position, and said chip handler means flips each IC-module 180° from an initial position where said electrical terminals face downward.
12. A system according to claim 2 wherein each chip holding subassembly is manually removable from said system at said load position, and manually returnable to said system at said load position.