Passivation layer surface topography modifications for improved integrity in packaged assemblies
A structure and method for producing the same is disclosed. The structure includes an organic passivation layer with solids suspended therein. Preferential etch to remove a portion of the organic material and expose portions of such solids creates enhanced surface roughness, which provides a significant advantage with respect to adhesion of that passivation layer to the packaging underfill material.
1. A structure comprising:
a passivation layer over a base structure, said passivation layer comprising an organic polymer material and an adhesion promoter having a silicon-containing end; and
a plurality of particles in said passivation layer comprising moisture bonded to said silicon-containing end of said adhesion promoter, wherein at least some of said plurality of particles are on a surface of said passivation layer and separated by a gap not containing said organic polymer material so that said surface of said passivation layer is a roughened surface.
2. The structure according to claim 1 , further comprising:
an encapsulation layer bonded to said roughened surface of said passivation layer.
3. The structure according to claim 1 , wherein said organic polymer material is polyimide, and said adhesion promoter comprises an aminosilane-like compound.
4. The structure according to claim 2 , further comprising:
a package assembly bonded to said encapsulation layer, and
wherein said base structure is an integrated circuit assembly comprising a device layer and a metallization layer, such that said device layer is in electrical contact with a portion of said package assembly.
5. The structure according to claim 1 wherein said particles have an average diameter between about 0.01 and 0.3 micron.
6. The structure according to claim 1 wherein a height variation of said roughened surface of said passivation layer is in the range of about 0.01 micron to 1.0 micron.
7. The structure according to claim 3 wherein said aminosilane-like compound is an aminosilane.
8. The structure according to claim 1 , wherein the roughened surface of said passivation layer comprises a smooth field portion and a micromask area.
9. The structure according to claim 8 , wherein the micromask area comprises a bump or a spike.
10. The structure according to claim 4 further comprising:
a contact structure to enable electrical connection of said metallization layer to said package assembly.
11. The structure according to claim 10 wherein said contact structure is adjacent to said encapsulation layer.
12. The structure according to claim 10 wherein said contact structure is a solder ball.
13. The structure of claim 1 further comprising a hard dielectric layer adjacent said passivation layer.
14. The structure of claim 1 further comprising a density of said particles in said passivation layer wherein said density is about 10 particles per micron cubed.
15. The structure of claim 1 , wherein said particles comprise about 5 percent of said passivation layer.
16. The structure of claim 1 , where said moisture bonded to said silicon-containing end of said adhesion promoter is a hydrolysis product.
17. The structure of claim 16 , where said hydrolysis product is selected from the group consisting of H and OH.