Package having redistribution layer structure with protective layer and method of fabricating the same

1. A package, comprising:

a die; and

a redistribution layer (RDL) structure electrically connected to the die, wherein the RDL structure comprises:

a dielectric layer comprising a first dielectric material and a second dielectric material over the first dielectric material;

a conductive feature electrically connected to the die, wherein the conductive feature comprises a first conductive pattern disposed over the first dielectric material and embedded in the second dielectric material; and

a first protective layer continuously covering a bottom surface and a sidewall of the first conductive pattern and being in contact with a top surface of the first dielectric material, wherein the first protective layer comprises an inorganic dielectric material, and two adjacent first conductive patterns are electrically isolated by the first protective layer therebetween.

2. The package of claim 1 , wherein the first protective layer extends from the bottom surface of the first conductive pattern to cover the sidewall of the first conductive pattern, so as to form a U-shape in cross-section.

3. The package of claim 2 , wherein the conductive feature further comprises a second conductive pattern and a third conductive pattern, the second conductive pattern is disposed in the second dielectric material, the third conductive pattern is disposed in the first dielectric material, and the second conductive pattern is disposed over and in contact with the third conductive pattern.

4. The package of claim 3 , wherein the RDL structure further comprises:

a second protective layer covering sidewalls of the second and third conductive patterns; and

a seed layer disposed between the second protective layer and the second and third conductive patterns, wherein the seed layer is free of between the second and third conductive patterns.

5. The package of claim 4 , wherein the first and second protective layers are conformal layers.

6. The package of claim 4 , wherein the second protective layer comprises an inorganic dielectric material and the inorganic dielectric material comprises an oxide, a nitride, an oxynitride, a carbide, or a combination thereof.

7. The package of claim 1 , wherein the conductive feature comprises a via in the first dielectric material and a trace in the second dielectric material, and the via has a top width greater than a bottom width thereof.

8. The package of claim 1 , further comprising an encapsulant laterally encapsulating the die, wherein the RDL structure is disposed over the encapsulant and the die.

9. The package of claim 1 , wherein the RDL structure further comprises a seed layer continuously covering the bottom surface and the sidewall of the first conductive pattern, wherein the seed layer is disposed between the first protective layer and the first conductive pattern.

10. A method of fabricating a package, comprising:

forming a redistribution layer (RDL) structure on a die, comprising:

forming a first dielectric material on the die;

forming a second dielectric material over the first dielectric material;

patterning the second dielectric material to form a first opening in the second dielectric material, wherein the second dielectric material has a plurality of comb portions in the first opening to separate the first opening into a plurality of sub-openings;

patterning the first and second dielectric materials to form a second opening in the first and second dielectric materials;

forming a protective layer on the die to cover the first and second openings;

removing a portion of the protective layer on a bottom surface of the second opening to expose the contact of the die;

filling the first opening and the second opening with a conductive material; and

performing a planarization process until exposing the plurality of comb portions, so as to form a plurality of first conductive patterns in the plurality of sub-openings and form a second conductive pattern in the second opening, wherein the protective layer has a first portion and a second portion, the first portion continuously covers bottom surfaces and sidewalls of the plurality of first conductive patterns and is in contact with a top surface of the first dielectric material, and the second portion continuously covers a sidewall of the second conductive pattern.

11. The method of claim 10 , wherein the forming the second opening comprises:

forming a via opening in the first dielectric material, the via opening exposing a contact of the die; and

forming a trench opening in the second dielectric material, wherein the trench opening is in spatial communication with the via opening to form the second opening.

12. The method of claim 10 , wherein the plurality of comb portions extend from the top surface of the first dielectric material upward, one of the plurality of comb portions has tapered sidewalls, and the one of the plurality of comb portions has a bottom width greater than a top width thereof.

13. The method of claim 10 , wherein after the performing the planarization process, the plurality of first conductive patterns in the plurality of sub-openings are separated into a plurality of traces by the plurality of comb portions.

14. The method of claim 10 , wherein the patterning the second dielectric material comprises performing a lithographic process, performing a laser ablation process, or performing a plasma etching process.

15. The method of claim 10 , wherein the planarization process comprises a chemical-mechanical polishing (CMP) process, a mechanical grinding process, a fly cutting process or an etching back process.

16. The method of claim 10 , wherein the first protective layer comprises an inorganic dielectric material, and two adjacent first conductive patterns are electrically isolated by the first portion of the protective layer therebetween.

17. A package structure, comprising:

a die having a front side and a back side;

an encapsulant laterally encapsulating the die; and

a first redistribution layer (RDL) structure disposed over the front side of the die and the encapsulant, wherein the first RDL structure comprises:

a dielectric layer comprising a first dielectric material and a second dielectric material over the first dielectric material;

a conductive feature electrically connected to the die, wherein the conductive feature comprises a first conductive pattern disposed over the first dielectric material and embedded in the second dielectric material; and

a first protective layer continuously covering a bottom surface and a sidewall of the first conductive pattern and being in contact with a top surface of the first dielectric material, wherein the first protective layer consists of an inorganic dielectric material.

18. The package structure of claim 17 , wherein the conductive feature further comprises a second conductive pattern and a third conductive pattern, the second conductive pattern is disposed in the second dielectric material, the third conductive pattern is disposed in the first dielectric material, and the second conductive pattern is disposed over and in contact with the third conductive pattern.

19. The package structure of claim 18 , wherein the RDL structure further comprises:

a second protective layer covering sidewalls of the second and third conductive patterns; and

a seed layer disposed between the second protective layer and the second and third conductive patterns, wherein the seed layer is free of between the second and third conductive patterns.

20. The package structure of claim 17 , further comprising:

a second RDL structure disposed over the back side of the die; and

a plurality of through interlayer vias (TIVs) aside the die and encapsulated by the encapsulant, wherein the TIVs is electrically connected to the first and second RDL structures.