Controlling adhesive reflow for transfer printing
Methods of making a printed structure include providing a target substrate, coating the target substrate with an uncured adhesive, disposing a component on the uncured adhesive, processing the uncured adhesive with or without a pattern, and curing the uncured adhesive. Some embodiments include having a target-substrate contact pad on the target substrate, disposing a post component on the uncured adhesive over the target-substrate contact pad, the post component having an electrical connection extending from the post component toward the target-substrate contact pad, disposing a non-post component on the uncured adhesive laterally displaced from the post component, pattern-wise processing the uncured adhesive so that a first portion of the uncured adhesive adjacent to the post component is not processed and a second portion of the uncured adhesive adjacent to the non-post component is processed, reflowing the unprocessed first portion of the uncured adhesive, and curing the uncured adhesive.
1 . A method of making a printed structure, the method comprising:
disposing a first component to a target substrate coated with an uncured adhesive;
disposing a second component to the target substrate;
pattern-wise processing the uncured adhesive so that a first portion of the uncured adhesive adjacent to the first component is not processed and a second portion of the uncured adhesive adjacent to the second component is processed;
reflowing the unprocessed first portion of the uncured adhesive; and
curing the uncured adhesive.
2 . The method of claim 1 , wherein the target substrate comprises a target-substrate contact pad and the first component is a post component comprising an electrical connection extending from the post component toward the target-substrate contact pad.
3 . The method of claim 2 , wherein the electrical connection is in contact with the target-substrate contact pad after the curing.
4 . The method of claim 1 , wherein the second component is a non-post component and is laterally displaced from the first component with respect to the target substrate.
5 . The method of claim 1 , wherein processing the second portion of the uncured adhesive comprises exposing the second portion of the adhesive to electromagnetic radiation through a mask.
6 . The method of claim 1 , wherein processing the second portion of the uncured adhesive comprises releasing a catalyst in the exposed second portion of the adhesive.
7 . The method of claim 1 , wherein processing the second portion of the adhesive diminishes a capacity of the second portion of the adhesive to reflow.
8 . The method of claim 1 , wherein reflowing the first portion of the adhesive moves the first component closer to the target substrate.
9 . The method of claim 1 , wherein curing the adhesive moves the first component closer to the target substrate and moves the second component closer to the target substrate.
10 . The method of claim 1 , comprising removing exposed adhesive that is not between the first component and the target substrate and is not between the second component and the target substrate.
11 . The method of claim 1 , wherein (i) disposing the first component comprises micro-transfer printing the first component onto the adhesive over the target substrate or (ii) disposing the second component comprises micro-transfer printing the second component onto the adhesive over the target substrate, or (iii) both (i) and (ii).
12 . The method of claim 1 , wherein the first component, the second component, or both the first component and the second component, has or have a lateral dimension no greater than 200 microns.
13 . The method of claim 1 , wherein (i) the first component comprises a broken or separated tether, (ii) the second component comprises a broken or separated tether, or (iii) both the first component and the second component comprise a broken or separated tether.
14 . The method of claim 1 , wherein the second portion of the uncured adhesive at least partially laterally surrounds the second component and/or laterally interposes between the first component and the second component.
15 . A printed structure, comprising:
a target substrate;
uncured adhesive disposed over the target substrate and the target-substrate contact pad;
a first component disposed on the uncured adhesive over the target-substrate contact pad; and
a second component disposed on the uncured adhesive and laterally displaced from the first component,
wherein a first portion of the uncured adhesive adjacent to the first component has not been processed and a second portion of the uncured adhesive adjacent to the second component has been processed.
16 . The printed structure of claim 15 , wherein the target substrate comprises a target-substrate contact pad, the uncured adhesive is disposed over the target-substrate contact pad, and the first component comprises an electrical connection extending from the first component toward the target-substrate contact pad.
17 . The printed structure of claim 15 , wherein the first component or the second component, both the first component and the second component, has or have a lateral dimension no greater than 200 microns.
18 . The printed structure of claim 15 , wherein (i) the first component comprises a broken or separated tether, (ii) the second component comprises a broken or separated tether, or (iii) both the first component and the second component comprise a broken or separated tether.
19 . The printed structure of claim 15 , wherein the processed second portion of the uncured adhesive has a reduced capacity to reflow compared to the first portion of the uncured adhesive.
20 . The printed structure of claim 15 , wherein the processed second portion of the uncured adhesive laterally surrounds.