Methods of making a bonded assembly and a re-entrant structure, and method of transfer printing a masking layer

1. A method of making a bonded polymeric assembly by transfer printing, the method comprising:

contacting a stamp with a solid-phase ink comprising a crosslinked photoresist to form an inked stamp, the solid-phase ink being reversibly bound to the stamp;

aligning the inked stamp with an object comprising the crosslinked photoresist;

stamping the inked stamp onto the object;

removing the stamp, thereby transferring the solid-phase ink onto the object; and

thermally joining the solid-phase ink with the object, thereby forming a bonded polymeric assembly including a bonded joint between the solid-phase ink and the object.

2. The method of claim 1 , wherein the bonded joint has an interfacial joining strength of at least about 0.9 J/m 2 .

3. The method of claim 1 , wherein the solid-phase ink is oriented on the object so as to include a suspended portion not supported by the object.

4. The method of claim 1 , wherein the object comprises a previously deposited solid-phase ink deposited prior to the stamping.

5. The method of claim 1 , wherein the thermal joining comprises heating the solid-phase ink and the object with a laser beam, a heat gun, a hot plate, and/or a furnace.

6. The method of claim 5 , wherein the laser beam has a wavelength in range from about 200 nm to about 400 nm.

7. The method of claim 5 , wherein the laser beam is generated by a pulsed laser.

8. The method of claim 1 , wherein no external pressure is applied during the thermal joining.

9. A method of making a bonded assembly by transfer printing, the method comprising:

coating a photoresist onto a donor substrate;

photolithographically patterning the photoresist to fabricate a solid-phase ink comprising the photoresist on the donor substrate;

contacting a stamp with the solid-phase ink to form an inked stamp, the solid-phase ink being reversibly bound to the stamp;

removing the inked stamp from the donor substrate;

aligning the inked stamp with an object;

stamping the inked stamp onto the object;

removing the stamp, thereby transferring the solid-phase ink onto the object; and

heating the solid-phase ink and the object with a laser beam to effect thermal joining, thereby forming a bonded joint between the solid-phase ink and the object.

10. The method of claim 9 , wherein the laser beam is generated by a pulsed laser.

11. The method of claim 9 , wherein thermal joining to form the bonded joint occurs in less than one second.

12. A method of transfer printing a masking layer, the method comprising:

contacting a stamp with a solid-phase ink comprising a crosslinked photoresist to form an inked stamp, the solid-phase ink being reversibly bound to the stamp;

aligning the inked stamp with a target substrate;

stamping the inked stamp onto the target substrate;

removing the stamp, thereby transferring the solid-phase ink comprising the crosslinked photoresist onto the target substrate to form a masking layer of a predetermined pattern thereon, the target substrate including one or more unmasked portions not covered by the masking layer;

processing the one or more unmasked portions of the target substrate; and

after the processing, removing the masking layer.

13. The method of claim 12 , wherein the target substrate comprises a semiconductor wafer,

wherein processing the one or more unmasked portions of the target substrate comprises material deposition and/or etching, and

wherein the target substrate includes one or more trenches, bumps or other surface features that inhibit spin-casting of photoresist.

14. The method of claim 12 , wherein forming the masking layer comprises multiple steps of transferring the solid-phase ink onto the target substrate, such that the contacting, aligning, stamping, and removing are repeated to form the masking layer, and

wherein the solid-phase inks are thermally joined to each other by laser heating.