Cost-saving scheme for scan testing of 3D stack die
A system and method for efficiently routing scan data between two dies used in three-dimensional packaging are described. In various implementations, a computing system includes at least a first semiconductor die (or first die) and a second die connected to one another within a three-dimensional (3D) package. The first die and the second die have multiple non-scan input/output (I/O) data channels between them for data transfer. The non-scan I/O data channels are partitioned into groups. The first die receives a given scan input data bit for testing a device under test (DUT) on the second die. The first die selects a first group of non-scan I/O data channels, and sends, to the second die, a copy of the given scan input data bit on each non-scan I/O data channel of the first group. The second die uses a voter circuit to determine the value of the given scan input data bit.
1. An integrated circuit comprising:
circuitry configured to:
receive, via a first interface, a given scan input data bit from automated test equipment for testing a device under test on a semiconductor die;
and
send, to the semiconductor die via a second interface, a copy of the given scan input data bit on each non-scan I/O data channel of a first group of non-scan I/O data channels, responsive to the first group of non-scan I/O data channels being selected from a first plurality of non-scan I/O data channels used to transfer a plurality of non-scan input data bits for the device under test between an integrated circuit and the semiconductor die.
2. The integrated circuit as recited in claim 1 , wherein the integrated circuit further comprises a table of mappings between scan input data bits for a device under test on the semiconductor die and groups of non-scan I/O data channels of the first plurality of non-scan I/O data channels, wherein the circuitry is further configured to access the table using an indication of the given scan input data bit.
3. The integrated circuit as recited in claim 2 , wherein the circuitry is further configured to select a given mapping from the table based on the indication of the given scan input data bit.
4. The integrated circuit as recited in claim 3 , wherein the circuitry is further configured to select the first group based on the given mapping.
5. The integrated circuit as recited in claim 1 , wherein the circuitry is further configured to:
receive, from a device under test on the semiconductor die via the second interface, a copy of a given scan output data bit on a majority of non-scan I/O data channels of a second group of non-scan I/O data channels of a second plurality of TSVs between the integrated circuit and the semiconductor die used to transfer a plurality of non-scan output data bits of the device under test.
6. The integrated circuit as recited in claim 5 , wherein the circuitry is further configured to:
determine an indication of the given scan output data bit based on an indication of the second group; and
send, to a memory via the first interface, the copy of the given scan output data bit on the majority of non-scan I/O data channels of the second group with the indication of the given scan output data bit.
7. The integrated circuit as recited in claim 5 , wherein the integrated circuit further comprises a voter circuit configured to:
receive, via the second interface, a plurality of scan output data bits on the second group; and
determine a value of the given scan output data bit on the majority of non-scan I/O data channels of the second group.
8. A method, comprising:
receiving, by a control unit of a first semiconductor die, a given scan input data bit for testing a device under test on a second semiconductor die;
and
sending, by the control unit to the second semiconductor die, a copy of the given scan input data bit on each non-scan I/O data channels of a first group of non-scan I/O data channels, responsive to the first group of non-scan I/O data channels being selected from a first plurality of non-scan I/O data channels used to transfer a plurality of non-scan input data bits for the device under test between an integrated circuit and the semiconductor die.
9. The method as recited in claim 8 , further comprising accessing, by the control unit using an indication of the given scan input data bit, a table of mappings between scan input data bits for a device under test on the second semiconductor die and groups of non-scan I/O data channels of the first plurality of non-scan I/O data channels.
10. The method as recited in claim 9 , further comprising selecting, by the control unit, a given mapping from the table based on the indication of the given scan input data bit.
11. The method as recited in claim 10 , further comprising selecting, by the control unit, the first group based on the given mapping.
12. The method as recited in claim 8 , further comprising:
receiving, by the control unit from a device under test on the second semiconductor die, a copy of a given scan output data bit on a majority of non-scan I/O data channels of a second group of non-scan I/O data channels of a second plurality of non-scan I/O data channels between the first semiconductor die and the second semiconductor die used to transfer a plurality of non-scan output data bits of the device under test.
13. The method as recited in claim 12 , further comprising:
determining, by the control unit, an indication of the given scan output data bit based on an indication of the second group; and
sending, by the control unit to a memory, the copy of the given scan output data bit on the majority of TSVs of the second group with the indication of the given scan output data bit.
14. The method as recited in claim 12 , further comprising:
receiving, by a voter circuit of the control unit, a plurality of scan output data bits on the second group; and
determining, by the voter circuit, a value of the given scan output data bit on the majority of non-scan I/O data channels of the second group.
15. A system in package, comprising:
a first semiconductor die; and
a second semiconductor die placed in a system in a package (SiP with the first semiconductor die;
wherein the first semiconductor die includes:
a control unit comprising circuitry configured to:
receive a given scan input data bit for testing a device under test on the second semiconductor die;
and
send, to the second semiconductor die, a copy of the given scan input data bit on each non-scan I/O data channel of a first group of non-scan I/O data channels, responsive to the first group of non-scan I/O data channels being selected from a first plurality of non-scan I/O data channels used to transfer a plurality of non-scan input data bits for the device under test between an integrated circuit and the semiconductor die.
16. The system in package as recited in claim 15 , wherein the control unit is further configured to access, using an indication of the given scan input data bit, a table of mappings between scan input data bits for a device under test on the second semiconductor die and groups of non-scan I/O data channels of the first plurality of non-scan I/O data channels.
17. The system in package as recited in claim 16 , wherein the control unit is further configured to select a given mapping from the table based on the indication of the given scan input data bit.
18. The system in package as recited in claim 17 , wherein the control unit is further configured to select the first group based on the given mapping.
19. The system in package as recited in claim 15 , wherein the control unit is further configured to:
receive, from a device under test on the second semiconductor die, a copy of a given scan output data bit on a majority of non-scan I/O data channels of a second group of non-scan I/O data channels of a second plurality of non-scan I/O data channels between the first semiconductor die and the second semiconductor die used to transfer a plurality of non-scan output data bits of the device under test.
20. The system in package as recited in claim 19 , wherein the control unit is further configured to:
determine an indication of the given scan output data bit based on an indication of the second group of TSVs; and
send, to a memory, the copy of the given scan output data bit on the majority of non-scan I/O data channels of the second group with the indication of the given scan output data bit.