Conductive structure, semiconductor package and methods of forming the same

Abstract

A conductive structure, a semiconductor package and methods of forming the same are disclosed. A conductive structure includes a metal feature, an insulating layer and a nitridized metal layer. The metal feature is disposed over a substrate and includes a lower metal pattern and an upper metal pattern over the lower metal pattern. The insulating layer surrounds the metal feature. The nitridized metal layer is disposed between the lower metal pattern and the upper metal pattern.

What is claimed is: 
     
         1 . A conductive structure, comprising:
 a metal feature disposed over a substrate and comprising a lower metal pattern and an upper metal pattern over the lower metal pattern;   an insulating layer surrounding the metal feature; and   a nitridized metal layer disposed between the lower metal pattern and the upper metal pattern.   
     
     
         2 . The conductive structure of  claim 1 , wherein a dimension of the lower metal pattern is different from a dimension of the upper metal pattern. 
     
     
         3 . The conductive structure of  claim 1 , wherein an edge of the nitridized metal layer is aligned with an edge of the upper metal pattern. 
     
     
         4 . The conductive structure of  claim 1 , wherein the nitridized metal layer is in physical contact with the lower metal pattern and the upper metal pattern. 
     
     
         5 . The conductive structure of  claim 1 , wherein the nitridized metal layer has a thickness of 0.1 nm to 100 nm. 
     
     
         6 . The conductive structure of  claim 1 , wherein the nitridized metal layer has a nitrogen atom content of about 1-30 at %. 
     
     
         7 . A semiconductor package, comprising:
 at least one die; and   a redistribution layer structure disposed over and electrically to the at least one die and comprising at least one metal feature,   wherein the at least one metal feature comprises a lower seed layer, a metal line, an upper seed layer and a metal via sequentially stacked and embedded by a polymer layer, and the lower seed layer and the upper seed layer comprise different materials.   
     
     
         8 . The semiconductor package of  claim 7 , wherein an edge of the upper seed layer is aligned with an edge of the metal via. 
     
     
         9 . The semiconductor package of  claim 7 , wherein the upper seed layer is in physical contact with the metal line and the metal via. 
     
     
         10 . The semiconductor package of  claim 7 , wherein the lower seed layer is thicker than the upper seed layer. 
     
     
         11 . The semiconductor package of  claim 10 , wherein a thickness of the lower seed layer is at least 5 times a thickness of the upper seed layer. 
     
     
         12 . The semiconductor package of  claim 7 , wherein the upper seed layer has a nitrogen atom content of about 1-30 at %. 
     
     
         13 . The semiconductor package of  claim 7 , wherein the lower seed layer comprises titanium and copper, and the upper seed layer comprises nitridized copper. 
     
     
         14 . A method of forming a conductive structure, comprising:
 forming a seed layer over a substrate;   forming a metal line by using the seed layer as a seed;   performing a nitrogen-containing plasma to form a metal protection layer on a surface of the metal line; and   forming a metal via by using the metal protection layer as a seed.   
     
     
         15 . The method of  claim 14 , wherein a method of forming the metal line comprises:
 forming a bottom anti-reflection coating layer over the seed layer;   forming a first photoresist layer over the bottom anti-reflection coating layer, wherein the first photoresist layer has a trench pattern that exposes a portion of the bottom anti-reflection coating layer;   removing the exposed portion of the bottom anti-reflection coating layer, so that the trench pattern of the first photoresist layer exposes a portion of the seed layer;   forming the metal line in the trench pattern of the first photoresist layer by using the exposed seed layer as a seed;   removing the first photoresist layer; and   removing the bottom anti-reflection coating layer.   
     
     
         16 . The method of  claim 15 , wherein the nitrogen-containing plasma is performed after removing the bottom anti-reflection coating layer. 
     
     
         17 . The method of  claim 16 , further comprising, after removing the first photoresist layer and before the nitrogen-containing plasma, performing an oxygen-containing plasma to remove the bottom anti-reflection coating layer aside the metal line. 
     
     
         18 . The method of  claim 15 , wherein the nitrogen-containing plasma is performed after removing the first photoresist layer and before removing the bottom anti-reflection coating layer. 
     
     
         19 . The method of  claim 18 , further comprising, after the nitrogen-containing plasma, performing an oxygen-containing plasma to remove the bottom anti-reflection coating layer aside the metal line. 
     
     
         20 . The method of  claim 19 , further comprising performing another nitrogen-containing plasma after the oxygen-containing plasma.