Stamp with structured posts

1. A system for micro-transfer printing, comprising:

an array of micro-transfer printable devices formed on or in a source substrate, each micro-transfer printable device having a non-planar contact surface limited to a single side of the micro-transfer printable device opposite the source substrate; and

a micro-transfer printing stamp for micro-transfer printing the micro-transfer printable devices from the source substrate to a destination substrate, the micro-transfer printing stamp comprising:

a body, and

an array of posts extending from the body, wherein each post in the array of posts has a non-planar surface contour on the distal end of the post having at least one of a size and shape that corresponds to the non-planar contact surface of the micro-transfer printable device while picking up and transferring the micro-transfer printable device to the destination substrate with the micro-transfer printing stamp, wherein the non-planar surface contour of each post is limited to the non-planar contact surface of the micro-transfer printable device.

2. The system of claim 1 , wherein the non-planar contact surface of each micro-transfer printable device comprises a three-dimensional surface.

3. The system of claim 1 , wherein the non-planar contact surface of each micro-transfer printable device comprises one or more recesses.

4. The system of claim 1 , wherein the non-planar contact surface of each micro-transfer printable device comprises a structured surface with minimum height variation across the surface of at least 10 nm or a maximum height variation of 20 μm.

5. The system of claim 1 , wherein the non-planar contact surface of each micro-transfer printable device comprises a structured surface with a minimum height variation across the surface of at least 5 percent of the post height or a maximum height variation across the surface of less than or equal to 50 percent of the post height.

6. The system of claim 1 , wherein the non-planar surface contour at the distal end of each post has a plurality of non-contiguous planar portions that accommodate non-contiguous planar portions of the contact surface of a respective printable device.

7. The system of claim 6 , wherein two or more of the plurality of non-contiguous planar portions of each post are parallel.

8. The system of claim 6 , wherein two or more of the plurality of non-contiguous planar portions of each post are in the same plane.

9. The system of claim 6 , wherein two or more of the plurality of non-contiguous planar portions of each post are non-parallel and non-orthogonal.

10. The system of claim 6 , wherein the non-contiguous planar portions of each post have an area smaller than the corresponding non-contiguous planar portions of the contact surface of each printable device.

11. The system of claim 1 , wherein the non-planar surface contour is at least partly curved.

12. The system of claim 1 , wherein:

the non-planar surface of each post comprises a cavity;

the non-planar contact surface of each micro-transfer printable device comprises a protruding portion; and

each cavity corresponds to the protruding portion of a respective micro-transfer printable device having a non-planar contact surface during a transfer operation.

13. The system of claim 12 , wherein each cavity is larger than the protruding portion of a respective micro-transfer printable device.

14. The system of claim 13 , wherein each cavity has a different shape than the protruding portion of a respective micro-transfer printable device.

15. The system of claim 12 , wherein each cavity has a shape that is substantially similar to the protruding portion of a respective micro-transfer printable device.

16. The system of claim 1 , wherein the posts comprise a first post having a first non-planar surface contour at the distal end of the first post and a second post having a second non-planar surface contour at the distal end of the second post, wherein the second non-planar surface contour is different from the first non-planar surface contour.

17. A method of using a micro-transfer printing stamp, comprising:

providing an array of micro-transfer printable devices formed on or in a source substrate, each micro-transfer printable device having a non-planar contact surface limited to a single side of the micro-transfer printable device opposite the source substrate;

providing the micro-transfer printing stamp for micro-transfer printing the micro-transfer printable devices from the source substrate to a destination substrate, the micro-transfer printing stamp comprising:

a body, and

an array of posts extending from the body, wherein each post in the array of posts has a non-planar surface contour on the distal end of the post having at least one of a size and shape that corresponds to the non-planar contact surface of the micro-transfer printable device during micro-transfer printing, wherein the non-planar surface contour of each post is limited to the non-planar contact surface of the micro-transfer printable device;

pressing the non-planar surface at the distal end of one of the one or more posts against the non-planar contact surface of the micro-transfer printable devices to adhere each micro-transfer printable device to the distal end of a respective post;

removing the micro-transfer printable devices from the wafer with the micro-transfer printing stamp;

pressing the micro-transfer printable devices to a destination substrate with the micro-transfer printing stamp to adhere the micro-transfer printable devices to the destination substrate; and

removing the micro-transfer printing stamp from the micro-transfer printable devices, thereby transferring the micro-transfer printable devices to the destination substrate.

18. The method of claim 17 , comprising:

contacting the micro-transfer printing stamp to the source substrate, wherein each post of the micro-transfer printing stamp is displaced when placed in contact with a respective non-planar contact surface of the micro-transfer printable device on the source wafer; and

removing the micro-transfer printing stamp from the source substrate to release the micro-transfer printable device from the source substrate.

19. A system for micro-transfer printing, comprising:

an array of micro-transfer printable devices formed on or in a source substrate, each micro-transfer printable device having a first side with a contact surface limited to the first side and a second side, opposite the first side, with one or more protrusions thereon; and

a micro-transfer printing stamp for micro-transfer printing the micro-transfer printable devices from the source substrate to a destination substrate, the micro-transfer printing stamp comprising:

a body,

an array of posts extending from the body,

wherein each post in the array of posts has a non-planar surface contour on the distal end of the post such that discrete portions of the non-planar surface contour contact the contact surface of a respective micro-transfer printable device while picking up and transferring the micro-transfer printable device to the destination substrate with the micro-transfer printing stamp, wherein the non-planar surface contour of each post is limited to the contact surface of the first side of the micro-transfer printable device.

20. The system of claim 19 , wherein the micro-transfer printing stamp provides non-uniform pressure over the contact surface.