Xerographic micro-assembler
View Patent ↗Xerographic micro-assembler systems and methods are disclosed. The systems and methods involve manipulating charge-encoded micro-objects. The charge encoding identifies each micro-object and specifies its orientation for sorting. The micro-objects are sorted in a sorting unit so that they have defined positions and orientations. The sorting unit has the capability of electrostatically and magnetically manipulating the micro-objects based on their select charge encoding. The sorted micro-objects are provided to an image transfer unit. The image transfer unit is adapted to receive the sorted micro-objects, maintain them in their sorted order and orientation, and deliver them to a substrate. Maintaining the sorted order as the micro-objects are delivered to the substrate may be accomplished through the use of an electrostatic image, as is done in xerography. The substrate with the micro-objects is further processed to interconnect the micro-objects—through electrical wiring, for example—to form the final micro-assembly.
1. A method of forming a micro-assembly, comprising:
sorting and orienting a plurality of micro-objects;
providing the sorted and oriented micro-objects to an image transfer unit;
transferring the sorted and oriented micro-objects from the image transfer unit to a substrate; and
fixing the transferred micro-objects to the substrate to form a micro-assembly.
2. The method of claim 1 , wherein the image transfer unit includes a rotatable drum having an outer surface that supports an electrostatic image, and further including:
providing a select electrostatic image to the drum outer surface; and
securing the micro-objects to the outer surface via the select electrostatic image while transferring the micro-objects to the substrate.
3. The method of claim 1 , including encoding some or all of the micro-objects with a patterned charge, and wherein said sorting and orienting includes electrically and/or magnetically manipulating the micro-objects based on the charge.
4. The method of claim 3 , including sorting the charge-encoded micro-objects by providing a dynamic electrostatic field matched to the encoded charge.
5. The method of claim 1 , including:
forming the micro-objects in a semiconductor wafer; and
dicing the semiconductor wafer.
6. The method of claim 5 , further including forming a charge-encoded pattern on the micro-objects prior to dicing.
7. The method of claim 5 , further including forming a charge-encoded pattern by inkjet printing.
8. The method of claim 1 , wherein some or all of the micro-objects are selectively charge-encoded, and wherein the sorting includes:
suspending the micro-objects in a liquid medium; and
conveying some or all micro-objects from the liquid to the image transfer unit via a dynamic electrostatic field matched to the selectively charge-encoded micro-objects.
9. The method of claim 1 , including:
forming the micro-objects to have an encoded charge;
subjecting the charge-encoded micro-objects to a dynamic electrostatic field matched to some or all of the charge-encoded micro-objects so as to orient and convey said some or all micro-objects to the image transfer unit.
10. The method of claim 9 , including:
providing the dynamic electrostatic field with a transport field that moves some or all of the micro-objects toward the image transfer unit and; providing the dynamic electrostatic field with an annealing field that randomly fluctuates.
11. The method of claim 10 , further including moving the annealing field away from the image transfer unit.
12. The method of claim 10 , wherein the transport field and the annealing field have respective strengths, and further including spatially varying the strength of the transport field and the strength of the annealing field to reduce movement of the micro-objects as the micro-objects get closer to the image transfer unit.
13. The method of claim 1 , further including after said transferring: electrically connecting two or more of the micro-objects.
14. The method of claim 1 , further including charge-encoding the micro-objects by adding charge-encoding elements to microchips formed in a wafer prior to the wafer being diced into the microchips.
15. The method of claim 13 , further including after said transferring: removing the charge-encoding elements from the micro-objects.
16. The method of claim 15 , further including:
planarizing the micro-objects and the substrates to expose a portion of corresponding micro-bodies with the micro-objects; and
operably interconnecting the micro-bodies.
17. The method of claim 1 , including providing the micro-objects as sets of different micro-objects with different charge-encoded patterns.
18. A method of forming a micro-assembly, comprising:
encoding each of one or more micro-objects with a patterned charge that identifies each micro-object and specifies its orientation;
sorting the charge-encoded micro-objects based on their encoded charge;
providing the sorted charge-encoded micro-objects to a xerographic imaging unit adapted to receive and carry the sorted charge-encoded micro-objects;
transferring the sorted charge-encoded micro-objects from the xerographic imaging unit to a substrate; and
fixing the transferred micro-objects to the substrate to form a micro-assembly.
19. The method of claim 18 , including providing an electrostatic image to the xerographic imaging unit to facilitate maintaining said sorting during said transferring.
20. The method of claim 18 , including providing the xerographic imaging unit with a conveyor.
21. The method of claim 20 , including providing the xerographic imaging unit with a drum adapted to support an electrostatic image.
22. The method of claim 18 , including manipulating the micro-objects using a dynamic electrostatic field.
23. The method of claim 22 , including manipulating the micro-objects using a magnetic field.