Bonded assembly having improved adhesive bond strength
View Patent ↗A bonded assembly is provided. The bonded assembly comprises: (a) a first substrate having a plurality of etched trenches defined in a first bonding surface; and (b) a second substrate having a second bonding surface. The second bonding surface is bonded to the first bonding surface with an adhesive and the adhesive is received, at least partially, in the plurality of etched trenches. Semiconductors chips bonded to a second substrate exemplify the advantages of the invention. The etched trenches allow the adhesive bond to be strengthened whilst avoiding increased surface roughening.
1. A bonded assembly comprising:
(a) a printhead integrated circuit having a plurality of ink supply channel inlets and a plurality of etched trenches defined in a first bonding surface thereof, and
(b) a molded polymer ink manifold having a second bonding surface, the second bonding surface being bonded to the first bonding surface with an adhesive tape comprising a liquid-based adhesive,
wherein the adhesive tape has a plurality of laser-drilled holes defined therein to coincide with the ink supply channel inlets defined in said first bonding surface, said holes and said ink supply channel inlets having substantially the same width, and
wherein the adhesive is received, at least partially, in the plurality of etched trenches.
2. The bonded assembly of claim 1 , wherein the printhead integrated circuit has a thickness of less than 1000 microns.
3. The bonded assembly of claim 1 , wherein the printhead integrated circuit has a thickness of less than 250 microns.
4. The bonded assembly of claim 1 , wherein the printhead integrated circuit is a semiconductor integrated circuit.
5. The bonded assembly of claim 1 , wherein the printhead integrated circuit is a MEMS integrated circuit.
6. The bonded assembly of claim 1 , wherein the ink manifold has a plurality of printhead integrated circuits mounted thereon.
7. The bonded assembly of claim 1 , wherein the etched trenches have a diameter or a width sufficient to draw in a liquid adhesive by capillary action.
8. The bonded assembly of claim 1 , wherein the etched trenches have a diameter or a width of less than about 10 microns.
9. The bonded assembly of claim 1 , wherein the etched trenches have a depth of at least 20 microns.
10. The bonded assembly of claim 1 , wherein the etched trenches have an aspect ratio of at least 3.1.
11. The bonded assembly of claim 1 , wherein the etched trenches increase the effective surface area of the first bonding surface by at least 20%.
12. The bonded assembly of claim 1 , wherein the first bonding surface has a maximum surface roughness R max of less than about 20 nm.
13. The bonded assembly of claim 1 , wherein the first bonding surface has a maximum surface roughness R max of less than about 5 nm.
14. The bonded assembly of claim 1 , wherein the first bonding surface has an average surface roughness R a of less than about 20 nm.
15. The bonded assembly of claim 1 , wherein the first bonding surface has an average surface roughness R a of less than about 5 nm.
16. The bonded assembly of claim 1 , wherein the first substrate has a Total Thickness Variation (TTV) of less than about 5 microns.