SCAN TESTABLE THROUGH SILICON VIAs
The disclosure describes a novel method and apparatus for testing different types of TSVs in a single die or different types of TSV connections in a stack of die. The testing is facilitated by test circuitry associated with each type of TSV. The test circuitry includes a scan cell adapted for testing TSVs.
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This application claims priority from Provisional Application No. 61/577,401, filed Dec. 19, 2011.
This disclosure is related to pending TI patent TI-71609 which is incorporated herein by reference.
FIELD OF THE DISCLOSUREThis disclosure relates generally to die having through silicon/substrate vias (TSVs) and specifically to the testing of the TSVs.
BACKGROUND OF THE DISCLOSUREIntegrated circuit die may be designed for stacking using TSVs. TSVs are vertical conductive paths formed between the bottom surface of the die and top surface of the die. TSVs may be formed in the die using conductive material, such as but not limited to copper. TSVs allow thousands or tens of thousands of vertical connections to be made between the dies in a stack. The advantage of stacking die using TSVs over older approaches, such as die stacking based on peripheral bond wire connections, is a greater number of higher speed interconnects may exist between die in a stack. Also the physical size of the die stack is reduced since the TSV connections are made between the bottom and top surfaces of the die, i.e. the die do not need a periphery connection area.
TSV 102 forms a non-buffered input and/or output (I/O) path between contact point 118 on the bottom surface 114 of the die and contact point 116 on the top surface 112 of the die. TSV 104 and buffer 120 form a buffered input (I) path from contact point 118 of the bottom surface 114 of the die to contact point 116 on the top surface 112 of the die. TSV 106 and buffer 122 form a buffered input (I) path from contact point 116 of the top surface 112 of the die to contact point 118 on the bottom top surface 114 of the die. TSV 108 and buffers 124 and 126 form a doubled buffered input (I) path from contact point 118 on the bottom surface 114 of the die to contact point 116 on the top surface 112 of the die. TSV 110 and buffers 128 and 130 form a doubled buffered input (I) path from contact point 116 on the top surface 112 of the die to contact point 118 on the bottom surface 114 of the die.
During the manufacture of Die 100, each TSV 102-110 path should be tested for connectivity to insure signals may be passed between contact points 118 on the bottom surface of the die and contact points 116 on the top surface of the die. If die 100 had ten thousand TSVs to test, a die tester would have to have the resources to test all ten thousand TSVS, which can be a very expensive proposition.
After stacking the Die 100, each stacked TSV 102-110 path should be tested for connectivity to insure signals may be passed between contact points 118 of the bottom surface of the lower die and contact points 116 on the top surface of the upper die. If the two die 100 had ten thousand TSVs to test, a stack die tester would have to have the resources to test all ten thousand TSVS, which can be a very expensive proposition.
BRIEF SUMMARY OF THE DISCLOSUREThe following disclosure describes a method and apparatus for testing TSV paths in a die or in a stack of die using a scan architecture that includes circuits and scan cells adapted for testing TSV paths. Advantageously, the scan architecture may be accessed with a minimum number of contacts and using very low cost testers.
In
When accessed, scan cell 302 operates in either a capture or shift mode. The capture and shift operation modes of the scan cell are controlled by the control inputs (CI) to the scan cell. During capture operations, the output of comparator 402 is selected to be loaded into FF 406 by the SC input, via multiplexer 404. During shift operations, FF 406 is controlled to shift data from SI to SO by the SC input, via multiplexer 404. During either the capture or shift operation, the stimulus output circuit 408 may be enabled or disabled by the OE input. If disabled, the data contained in FF 406 will not be produce a stimulus (S) output from the scan cell 302. If enabled, the data contained in FF 306 will produce a stimulus (S) output from the scan cell 302. During all capture operations, the response (R) voltage input to the scan cell 302 will be loaded into FF 406. The VR input to comparator 402 is set to a desired voltage reference level that will digitize the response (R) voltage input to a logical one or zero to be loaded into FF 406 via multiplexer 404.
While
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The voltage potential applied from the S output of the scan cell may need to be decreased during TSV resistance testing, to lessen the current through the TSVs and load resistors. An example circuit for selecting a high or low voltage level at the V terminal of the stimulus output circuit will be described in regard to
During functional operation, buffers 2002 of die 2100 and 2102 are enabled, the S outputs of scan cells 302 are disabled and switches 308 are opened. In this mode, functional signals may be passed from contact point 118 of the die 2100 to contact point 116 of die 2102.
During separate testing of the TSVs of die 2100 and 2102, buffers 2002 are disabled, the S outputs of the scan cells 302 are enabled and the scan cells are controlled to perform capture and shift operations. Switch 308 is open during TSV signaling, continuity and shorts testing and closed during TSV resistance testing, as previously described.
During combined testing of the TSVs of die 2100 and 2102, buffer 2002 of die 2102 is enabled, buffer 2002 of die 2100 is disabled, the S output of scan cell 302 of die 2100 is enabled and the S output of scan cell 302 of die 2102 is disabled. The scan cells 302 are operated to perform capture and shift operations. Switches 308 are open during TSV signaling, continuity and shorts testing. One or both of switches 308 may be closed during TSV resistance testing, as previously described.
During functional operation, buffers 2202 of die 2300 and 2302 are enabled, the S outputs of scan cells 302 are disabled and switches 308 are opened. In this mode, functional signals may be passed from contact point 116 of the die 2302 to contact point 118 of die 2300.
During separate testing of the TSVs of die 2300 and 2302, buffers 2202 are disabled, the S outputs of the scan cells 302 are enabled and the scan cells are controlled to perform capture and shift operations. Switch 308 is open during TSV signaling, continuity and shorts testing and closed during TSV resistance testing, as previously described.
During combined testing of the TSVs of die 2300 and 2302, buffer 2202 of die 2300 is enabled, buffer 2202 of die 2302 is disabled, the S output of scan cell 302 of die 2302 is enabled and the S output of scan cell 302 of die 2300 is disabled. The scan cells 302 are operated to perform capture and shift operations. Switches 308 are open during TSV signaling, continuity and shorts testing. One or both of switches 308 may be closed during TSV resistance testing, as previously described.
During functional operation, buffers 2402 of die 2500 and 252 are enabled, the S outputs of scan cells 302 are disabled and switches 308 are opened. In this mode, functional signals may be passed from contact point 118 of the die 2500 to contact point 116 of die 2502.
During separate testing of the TSVs of die 2500 and 2502, buffers 2402 are disabled, the S outputs of the scan cells 302 are enabled and the scan cells are controlled to perform capture and shift operations. Switch 308 is open during TSV signaling, continuity and shorts testing and closed during TSV resistance testing, as previously described.
During combined testing of the TSVs of die 2500 and 2502, buffer 2402 of die 2502 is enabled, buffer 2402 of die 2500 is disabled, the S output of scan cell 302 of die 2500 is enabled and the S output of scan cell 302 of die 2502 is disabled. The scan cells 302 are operated to perform capture and shift operations. Switches 308 are open during TSV signaling, continuity and shorts testing. One or both of switches 308 may be closed during TSV resistance testing, as previously described.
During functional operation, buffers 2602 of die 2700 and 2702 are enabled, the S outputs of scan cells 302 are disabled and switches 308 are opened. In this mode, functional signals may be passed from contact point 116 of the die 2702 to contact point 118 of die 2700.
During separate testing of the TSVs of die 2700 and 2702, buffers 2602 are disabled, the S outputs of the scan cells 302 are enabled and the scan cells are controlled to perform capture and shift operations. Switch 308 is open during TSV signaling, continuity and shorts testing and closed during TSV resistance testing, as previously described.
During combined testing of the TSVs of die 2700 and 2702, buffer 2602 of die 2700 is enabled, buffer 2602 of die 2702 is disabled, the S output of scan cell 302 of die 2702 is enabled and the S output of scan cell 302 of die 2700 is disabled. The scan cells 302 are operated to perform capture and shift operations. Switches 308 are open during TSV signaling, continuity and shorts testing. One or both of switches 308 may be closed during TSV resistance testing, as previously described.
When only the scan cells 302 of die 3600 are accessed, the UC signals to die 3600 are set to gate off certain ones or all of the CB signals to the CB terminals 3608 on the bottom surface of die 3602 via gating circuit 3606. Also the UC signals control multiplexer 3604 of die 3600 to pass the SO of the last scan cell in die 3600 to the SO terminal on the bottom surface of die 3600. During scan operations, data is shifted from the SI terminal on the bottom surface of die 3600, through the scan cells 302 of die 3600 and to the SO terminal on the bottom surface of die 3600.
When the scan cells 302 of die 3600 and 3602 are accessed together, the UC signals to die 3600 are set to gate on the CB signals to the CB terminals 3608 on the bottom surface of die 3602 via gating circuit 3606. As seen, the SO of the last scan cell of die 3600 is connected to the S13610 of the first scan cell of die 3602. The UC signals also control multiplexer 3604 of die 3602 to output the SO of the last scan cell of die 3602 to multiplexer 3604 of die 3600, and control multiplexer 3604 of die 3600 to output the SO from die 3602 to the SO terminal on the bottom surface of die 3600. During scan operations, data is shifted from the SI terminal on the bottom surface of die 3600, through the scan cells 302 of die 3600 and 3602 and to the SO terminal on the bottom surface of die 3600.
If another die, having the same TSV scan cell architecture as die 3600 and 3602, were stacked on top of die 3602, the scan cells of the other die could be concatenated with the scan cells of die 3602 and 3600, by using the UC signals to appropriately control multiplexers 3604 and gating circuits 3606 of each die in the stack.
When only the scan cells 302 of die 3800 are accessed, the TAP outputs control on the CB outputs to operate CI inputs to the scan cells, control to operate the VS circuit 3404, control to the other signals and control to gating circuit 3804 to gate off one or both of the TCK and TMS signals to the bottom surface of die 3802. During scan operations, data is shifted from the TAP TDI terminal on the bottom surface of die 3800, through the scan cells 302 of die 3800 and to the TAP TDO terminal on the bottom surface of die 3800.
When the scan cells 302 of die 3800 and 3802 are accessed together, the gating circuit 3804 of die 3800 is enabled by control from the CB bus to pass the TCK and TMS signals from the TAP of die 3800 to the TAP of die 3802. The TCK and TMS signals simply pass through the TAP 3704 from the bottom surface TCK and TMS terminals to the gating circuit 3804, as indicated in dotted line. As seen, TAP 3704 of die 3800 provides a TDI input to TAP 3804 of die 3802 and receives a TDO output from TAP 3704 of die 3802. During scan operations, data is shifted from the TDI terminal on the bottom surface of die 3800, through the scan cells 302 of die 3800, through the TAP of die 3800 to the TDI terminal on the bottom surface of die 3802, through the scan cells 302 of die 3802, through the TAP of die 3802 to the TDO output on the bottom surface of die 3802 and through the TAP of die 3800 to the TDO terminal on the bottom surface of die 3800.
If another die, having the same TSV scan cell architecture as die 3800 and 3802, were stacked on top of die 3802, the scan cells of the other die could be concatenated with the scan cells of die 3800 and 3802 by appropriately controlling the TAPs 3704 and gating circuits 3804 of the die in the stack.
Although the disclosure has been described in detail, it should be understood that various changes, substitutions and alterations may be made without departing from the spirit and scope of the disclosure as defined by the appended claims.
Claims
1. An integrated circuit die including;
- a top surface and a bottom surface,
- a contact point on the top surface,
- a contact point on the bottom surface,
- a TSV having a top end and bottom end,
- a scan cell having a response input and a stimulus output,
- a first switch selectively coupling the top end of the TSV to one of the top surface contact point and the response input to the scan cell,
- a second switch selectively coupling the bottom end of the TSV to one of the bottom surface contact point and the stimulus output of the scan cell, and;
- a first control signal for controlling the first switch and a second control signal for controlling the second switch.
2. The integrated circuit die of claim 1 further including a third switch for selectively connecting a load resistor to the response input to the scan cell and a third control signal for controlling the third switch.
3. An integrated circuit die including;
- a top surface and a bottom surface,
- a contact point on the top surface,
- a contact point on the bottom surface,
- a TSV having a top end and bottom end,
- a scan cell having a response input and a stimulus output,
- a connection formed between the top end of the TSV, the top surface contact point and the response input to the scan cell,
- a switch selectively coupling the bottom end of the TSV to one of the bottom surface contact point and the stimulus output of the scan cell, and;
- a control signal for controlling the switch.
4. The integrated circuit die of claim 3 further including a second switch for selectively connecting a load resistor to the response input to the scan cell and a second control signal for controlling the second switch.
5. An integrated circuit die including;
- a top surface and a bottom surface,
- a contact point on the top surface,
- a contact point on the bottom surface,
- a TSV having a top end and bottom end,
- a scan cell having a response input and a stimulus output,
- a connection formed between the top end of the TSV, the top surface contact point and the response input to the scan cell,
- a 3-state buffer having an input connected to the bottom surface contact point, a control input and an output connected to the bottom end of the TSV and the stimulus output of the scan cell, and;
- a control signal for controlling the control input of the 3-state buffer.
6. The integrated circuit die of claim 5 further including a switch for selectively connecting a load resistor to the response input to the scan cell and a control signal for controlling the switch.
7. An integrated circuit die including;
- a top surface and a bottom surface,
- a contact point on the top surface,
- a contact point on the bottom surface,
- a TSV having a top end and bottom end,
- a scan cell having a response input and a stimulus output,
- a connection formed between the bottom end of the TSV, the bottom surface contact point and the response input to the scan cell,
- a 3-state buffer having an input connected to the top surface contact point, a control input and an output connected to the top end of the TSV and the stimulus output of the scan cell, and;
- a control signal for controlling the control input of the 3-state buffer.
8. The integrated circuit die of claim 7 further including a switch for selectively connecting a load resistor to the response input to the scan cell and a control signal for controlling the switch.
9. An integrated circuit die including;
- a top surface and a bottom surface,
- a contact point on the top surface,
- a contact point on the bottom surface,
- a TSV having a top end and bottom end,
- a scan cell having a response input and a stimulus output,
- a 3-state buffer having an input connected to the bottom surface contact point, a control input and an output connected to the bottom end of the TSV and the stimulus output of the scan cell,
- a buffer having an input connected to the top end of the TSV and the response input to the scan cell and an output connected to the top surface contact point, and;
- a control signal for controlling the control input of the 3-state buffer.
10. The integrated circuit die of claim 9 further including a switch for selectively connecting a load resistor to the response input to the scan cell and a control signal for controlling the switch.
11. An integrated circuit die including;
- a top surface and a bottom surface,
- a contact point on the top surface,
- a contact point on the bottom surface,
- a TSV having a top end and bottom end,
- a scan cell having a response input and a stimulus output,
- a 3-state buffer having an input connected to the top surface contact point, a control input and an output connected to the top end of the TSV and the stimulus output of the scan cell,
- a buffer having an input connected to the bottom end of the TSV and the response input to the scan cell and an output connected to the bottom surface contact point, and;
- a control signal for controlling the control input of the 3-state buffer.
12. The integrated circuit die of claim 11 further including a switch for selectively connecting a load resistor to the response input to the scan cell and a control signal for controlling the switch.
13. An integrated circuit die including;
- a top surface and a bottom surface,
- a contact point on the top surface,
- a contact point on the bottom surface,
- a TSV having a top end and bottom end,
- a scan cell having a response input and a stimulus output,
- a 3-state buffer having an input connected to the bottom surface contact point, a control input and an output connected to the bottom end of the TSV and the stimulus output of the scan cell,
- a buffer having an input connected to the top end of the TSV and an output connected to the top surface contact point,
- a switch having a first terminal connected to the buffer input, a second terminal connected to the buffer output, a third terminal connected to the response input of the scan cell and a control input, and;
- a control signal for controlling the control input of the 3-state buffer and a control signal for controlling the control input of the switch.
14. The integrated circuit die of claim 13 further including a second switch for selectively connecting a load resistor to the response input to the scan cell and a control signal for controlling the second switch.
15. An integrated circuit die including;
- a top surface and a bottom surface,
- a contact point on the top surface,
- a contact point on the bottom surface,
- a TSV having a top end and bottom end,
- a scan cell having a response input and a stimulus output,
- a 3-state buffer having an input connected to the top surface contact point, a control input and an output connected to the top end of the TSV and the stimulus output of the scan cell,
- a buffer having an input connected to the bottom end of the TSV and an output connected to the bottom surface contact point,
- a switch having a first terminal connected to the buffer input, a second terminal connected to the buffer output, a third terminal connected to the response input of the scan cell and a control input, and;
- a control signal for controlling the control input of the 3-state buffer and a control signal for controlling the control input of the switch.
16. The integrated circuit die of claim 15 further including a second switch for selectively connecting a load resistor to the response input to the scan cell and a control signal for controlling the second switch.
17. An integrated circuit die including;
- a top surface and a bottom surface,
- a contact point on the top surface,
- a contact point on the bottom surface,
- a TSV coupled between the top surface contact point and bottom surface contact point,
- test circuitry associated with the TSV,
- a functional output circuit coupled to the TSV via a 3-state buffer which is part of the test circuitry, and;
- a test mode signal connected to the control input of the 3-state buffer for disabling the 3-state buffer when the TSV is being tested by the test circuitry.
18. An integrated circuit die including;
- a top surface and a bottom surface,
- a contact point on the top surface,
- a contact point on the bottom surface,
- a TSV coupled between the top surface contact point and bottom surface contact point, test circuitry associated with the TSV,
- a functional output circuit coupled to the TSV via a functional 3-state buffer,
- a control output from the functional output circuit for controlling the functional 3-state buffer to one of an enabled and disabled state,
- a gate having an first input connected to the control output of the output circuit, an output connected to a control input of the functional 3-state buffer and a second input, and:
- a test mode signal connected to the second input for disabling the functional 3-state buffer when the TSV is being tested by the test circuitry.
19. A scan cell within an integrated circuit including;
- a test response (R) input terminal, a voltage reference (VR) input terminal, a serial data input (SI) terminal, a capture/shift (CS) input terminal, a scan clock (SC) input terminal, an output enable (OE) input terminal, a serial data output (SO) terminal, a test stimulus (S) output terminal, a voltage (V) level terminal and a ground (G) level terminal.
- a comparator having an input coupled to the test response input terminal, an input coupled to the voltage reference input terminal and an output,
- a multiplexer having an input coupled to the output of the comparator, an input coupled to the serial data input terminal, an input coupled to the capture/shift input terminal and an output,
- a memory having an input coupled to the output of the multiplexer, an input coupled to the scan clock input terminal and an output coupled to the serial data output terminal, and;
- a stimulus output circuit having an input coupled to the output of the memory, an input coupled to the output enable input terminal, a connection to the voltage level terminal, a connection to the ground level terminal and an output coupled to the test stimulus output terminal.
20. The stimulus output circuit of claim 19 including:
- a switch having a control input lead connected to the output of the memory, voltage lead connected to the voltage level terminal, a ground lead connected to the ground level terminal, and an output lead, and:
- a unity gain amplifier having an input lead connected to the output lead of the switch, a control input lead connected to the output enable terminal and an output lead connected to the test stimulus terminal.
21. An integrated circuit including;
- a voltage reference contact point, a serial input contact point, control bus contact points, a serial output contact point,
- a voltage selection circuit having an output for providing a selectable voltage level and a voltage selection control input from the control bus, and;
- scan cells connected serially between the serial input and serial output contact points, each scan cell having control inputs connected to control signals of the control bus contact points and a voltage level lead connected to the voltage level output of the voltage selection circuit.
22. An integrated circuit including;
- a bottom surface including a voltage reference contact point, a serial input contact point, control bus contact points, up control contact points, and a serial output contact point,
- a top surface including a voltage reference contact point, a serial output contact point, control bus contact points, up control contact points, and a serial input contact point,
- a voltage selection circuit having an output for providing a selectable voltage level and a voltage selection control input from the control bus contact points of the bottom surface,
- a group of serially connected scan cells, the group having a data input connected to the bottoms surface serial input terminal, control inputs connected to some of the bottom surface control bus contact points and a data output, and;
- a multiplexer having an input connected to the data output of the group of serial connected scan cells, an input connected to the serial input contact point of the top surface and an output connected to the serial output contact point on the bottom surface.
23. An integrated circuit including;
- a voltage reference contact point and TDI, TCK, TMS and TDO contact points,
- a TAP connected to the TDI, TCK, TMS and TDO contact points and having TDI output lead, a TDO input lead and control bus output leads,
- a voltage selection circuit having an output for providing a selectable voltage level and a voltage selection control input from the control bus output leads, and;
- scan cells connected serially between the TAP TDI output lead and TDO input lead, each scan cell having control inputs connected to control signals of the control bus output leads and a voltage level lead connected to the voltage level output of the voltage selection circuit.
24. An integrated circuit including;
- a bottom surface including a voltage reference contact point and TDI, TCK, TMS and TDO contact points,
- a top surface including a voltage reference terminal and TDI, TCK, TMS, and TDO contact points,
- a TAP connected to the TDI, TCK, TMS and TDO contact points of the bottom surface and having first and second TDI output leads, first and second TDO input leads and control bus output leads,
- a voltage selection circuit having an output for providing a selectable voltage level and a voltage selection control input from the control output bus of the TAP,
- a group of serially connected scan cells, the group having a data input connected to the first TDI output lead, control inputs connected to some of the control bus output leads, and a data output connected to the first TDO input lead,
- a connection formed between the second TDI output lead and the TDI contact point on the top surface,
- a connection formed between the TDO contact point on the top surface and the second TDO input lead, and;
- gating circuitry selectively coupling at least one of the TCK and TMS contact points of the bottom surface to a respective one of the TCK and TMS contact points of the top surface.
Type: Application
Filed: Dec 12, 2012
Publication Date: Jun 20, 2013
Applicant: TEXAS INSTRUMENTS INCORPORATED (Dallas, TX)
Inventor: Texas Instruments Incorporated (Dallas, TX)
Application Number: 13/712,459
International Classification: H01L 21/66 (20060101);