BONDING OF LIGHT EMITTING DIODE ARRAYS
Disclosed herein are techniques for bonding arrays of light emitting diodes (LEDs) to a plurality of driver circuits. According to certain embodiments, a method includes forming an array comprising a plurality of LEDs on a first substrate, separating the array into a plurality of sub-arrays by forming a plurality of gaps between the plurality of sub-arrays, bonding the plurality of sub-arrays to a plurality of driver circuits that are formed on a second substrate, forming an underfill within the plurality of gaps, and removing the first substrate from the plurality of sub-arrays.
1 . A method comprising:
forming an array comprising a plurality of light emitting diodes (LEDs) on a first substrate;
separating the array into a plurality of sub-arrays by forming a plurality of gaps between the plurality of sub-arrays;
bonding the plurality of sub-arrays to a plurality of driver circuits that are formed on a second substrate;
forming an underfill within the plurality of gaps; and
removing the first substrate from the plurality of sub-arrays.
2 . The method of claim 1 , wherein the underfill is formed before the plurality of sub-arrays are bonded to the plurality of driver circuits.
3 . The method of claim 1 , wherein the underfill is formed after the plurality of sub-arrays are bonded to the plurality of driver circuits.
4 . The method of claim 1 , wherein the plurality of gaps are formed by dry etching.
5 . The method of claim 1 , wherein the plurality of gaps form a staggered pattern in the array.
6 . The method of claim 1 , wherein the plurality of gaps extend through a semiconductor material that forms the plurality of LEDs.
7 . The method of claim 6 , wherein the plurality of gaps extend through a film that is arranged between the plurality of LEDs and the first substrate before the first substrate is removed.
8 . The method of claim 6 , wherein the plurality of gaps extend through a portion of the first substrate before the first substrate is removed.
9 . The method of claim 1 , wherein the plurality of LEDs comprise a first material having a first thermal expansion coefficient, the second substrate comprises a second material having a second thermal expansion coefficient, and the first thermal expansion coefficient is different from the second thermal expansion coefficient.
10 . The method of claim 9 , wherein the first substrate has a third thermal expansion coefficient that is matched with the second thermal expansion coefficient.
11 . The method of claim 1 , further comprising applying a passivation layer adjacent to the plurality of gaps.
12 . The method of claim 1 , wherein the plurality of sub-arrays are bonded to the plurality of driver circuits via a plurality of interconnects.
13 . A device comprising:
an array comprising a plurality of light emitting diodes (LEDs) that are bonded to a plurality of driver circuits that are formed on a substrate, wherein:
the array is separated into a plurality of sub-arrays by a plurality of gaps, and
an underfill is formed within the plurality of gaps.
14 . The device of claim 13 , wherein the plurality of gaps form a staggered pattern in the array.
15 . The device of claim 13 , wherein the plurality of LEDs comprise a first material having a first thermal expansion coefficient, the substrate comprises a second material having a second thermal expansion coefficient, and the first thermal expansion coefficient is different from the second thermal expansion coefficient.
16 . The device of claim 13 , further comprising a passivation layer adjacent to the plurality of gaps.
17 . The device of claim 13 , further comprising a plurality of interconnects that connect the plurality of LEDs to a plurality of drivers within the plurality of driver circuits.