Integrated circuit bond pad with multi-material toothed structure
An integrated circuit device may include a multi-material toothed bond pad including (a) an array of vertically-extending teeth formed from a first material, e.g., aluminum, and (b) a fill material, e.g., silver, at least partially filling voids between the array of teeth. The teeth may be formed by depositing and etching aluminum or other suitable material, and the fill material may be deposited over the array of teeth and extending down into the voids between the teeth, and etched to expose top surfaces of the teeth. The array of teeth may collectively define an abrasive structure. The multi-material toothed bond pad may be bonded to another bond pad, e.g., using an ultrasonic or thermosonic bonding process, during which the abrasive teeth may abrade, break, or remove unwanted native oxide layers formed on the respective bond pad surfaces, to thereby create a direct and/or eutectic bonding between the bond pads.
1. A method of forming a multi-material toothed bond pad, the method comprising:
forming a layer of a first material;
etching the layer of the first material to define (a) a plurality of vertically-extending teeth formed from the first material and (b) open spaces between the plurality of vertically-extending teeth;
depositing a layer of the second material over the plurality of vertically-extending teeth and extending down into the open spaces between the plurality of vertically-extending teeth; and
removing portions of the second material over the plurality of vertically-extending teeth to expose upper surfaces of the plurality of vertically-extending teeth.
2. The method of claim 1 , wherein removing a portion of the second material over the plurality of vertically-extending teeth to expose upper surfaces of the plurality of vertically-extending teeth comprises etching portions of the second material over the plurality of vertically-extending teeth to expose upper surfaces of the plurality of vertically-extending teeth.
3. The method of claim 1 , wherein the first material comprises aluminum, and the second material comprises silver.
4. The method of claim 1 , further comprising performing a roughening process to increase a surface roughness of the plurality of vertically-extending teeth.
5. A bonding method, comprising:
providing a first integrated circuit (IC) device including a first IC device bond pad comprising:
a plurality of oxidized teeth, each oxidized tooth comprising a vertically-extending tooth formed from a first material and a first oxide layer formed on the vertically-extending tooth; and
a second material arranged in spaces between the plurality of oxidized teeth, the second material being different than the first material;
wherein the plurality of oxidized teeth define an abrasive structure; and
performing a bonding process to bond the first IC device of the first IC device to a second IC device bond pad of a second IC device, the second IC device bond pad having a second oxide layer formed thereon;
wherein during the bonding process, the abrasive structure defined by the plurality of oxidized teeth of the bond pad of the first IC device interacts with the second oxide layer formed on the second IC device bond pad to abrade, break, or remove the first oxide layer formed on the vertically-extending teeth and the second oxide layer formed on the second IC device bond pad.
6. The bonding method of claim 5 , wherein the bonding process includes applying ultrasonic energy to at least one of the first IC device bond pad and the second IC device bond pad.
7. The bonding method of claim 5 , wherein the bonding process includes using a thermosonic device to apply ultrasonic energy and heat to at least one of the first IC device bond pad and the second IC device bond pad.
8. The bonding method of claim 5 , wherein the bonding process causes a eutectic bonding between the first IC device bond pad and second IC device bond pad.
9. The bonding method of claim 5 , wherein the bonding process causes a eutectic bonding between (a) the first material forming the vertically-extending teeth of the first IC device bond pad, (b) the second material arranged in spaces between the plurality of vertically-extending teeth, and (c) the second IC device bond pad.
10. The bonding method of claim 9 , wherein:
the first material comprises aluminum;
the second material comprises silver; and
the second IC device bond pad comprises aluminum.
11. The method of claim 1 , comprising forming silicon nodules on the vertically-extending teeth.
12. The method of claim 1 , comprising forming an oxide layer on respective ones of the plurality of vertically-extending teeth.
13. The method of claim 1 , comprising forming an oxide layer on exposed upper surfaces of the plurality of vertically-extending teeth, so that respective vertically-extending teeth include (a) respective side surfaces covered by the second material and (b) respective upper surfaces uncovered by the second material and covered by the oxide layer.
14. The method of claim 1 , wherein the first material comprises aluminum, and the second material comprises silver.
15. A method of forming a multi-material toothed bond pad, the method comprising:
forming a plurality of vertically-extending teeth formed from a first material;
depositing a second material between the plurality of vertically-extending teeth, wherein the second material is softer than the first material;
removing portions of the deposited second material to expose upper surfaces of the vertically-extending teeth; and
forming an oxide layer on the exposed upper surfaces of respective ones of the plurality of vertically-extending teeth.
16. The method of claim 15 , comprising performing a roughening process to increase a surface roughness of the plurality of vertically-extending teeth.
17. The method of Claim 15 , wherein respective vertically-extending teeth include (a) respective side surfaces covered by the second material and (b) respective upper surfaces uncovered by the second material and covered by the oxide layer.
18. The method of claim 15 , comprising forming silicon nodules on the vertically-extending teeth.
19. The method of claim 15 , wherein the first material comprises aluminum, and the second material comprises silver.
20. A method of forming a multi-material toothed bond pad, the method comprising:
forming a plurality of vertically-extending teeth formed from a first material;
depositing a second material between the plurality of vertically-extending teeth, wherein the second material is softer than the first material; and
forming an oxide layer on respective ones of the plurality of vertically-extending teeth;
wherein respective vertically-extending teeth include (a) respective side surfaces covered by the second material and (b) respective upper surfaces uncovered by the second material and covered by the oxide layer.