Passivation layer surface topography modifications for improved integrity in packaged assemblies
View Patent ↗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 method comprising steps of:
providing a packaging structure and an integrated circuit chip, the integrated circuit chip including at least a device layer, a metallization layer and a passivation layer;
etching the passivation layer to roughen a top portion of the passivation layer thereby exposing one or more silicon-containing precipitates extending from the passivation layer;
electrically connecting the integrated circuit chip to the packaging structure through at least one contact structure; and
applying an encapsulation material to bond the integrated circuit chip and the packaging structure, wherein the encapsulation material bonds directly to the passivation layer;
wherein the one or more silicon-containing precipitates are created by hydrolysis during passivation layer formation or added to the passivation layer.
2. The method according to claim 1 , wherein the etching removes at least a portion of an organic polymer material to create the roughened surface.
3. The method according to claim 2 , wherein said roughened surface has a height variation in the range of 0.01 to 1.0 micron.
4. The method according to claim 1 , whereby the etching step is achieved by RIE exposure.
5. The method according to claim 1 , whereby the etching is optimized by application of an O 2 plasma ash process.
6. The method according to claim 1 , wherein said integrated circuit chip is an assembly comprising:
the device layer having one or more devices formed thereon; and
the metallization layer comprising an interconnect structure formed within at least one of a plurality of dielectric layers.
7. The method according to claim 1 , wherein the integrated circuit chip is one of a plurality of such chips formed on a single wafer, said method further comprising:
dicing said wafer to form individual chips after said applying step.
8. The method of claim 1 , wherein the passivation layer comprises a photosensitive polyimide material.
9. The method of claim 1 , wherein the passivation layer comprises an adhesion promoter.