Method for forming Barrier Layer and the Related Damascene Structure

Abstract

A method for forming barrier layers comprises steps of forming a first metal barrier layer covering a first dielectric layer and contacting a conductive layer through a via of the first dielectric layer, forming a barrier layer of metalized materials on the first metal layer, optionally forming a second metal barrier layer on the barrier layer of metalized materials, removing portions of the barrier layer of metalized materials above the via bottom in the first dielectric layer, and leaving the barrier layer of metalized materials remaining on the via sidewall in the first dielectric layer; and forming a second metal layer covering the barrier layer of metalized materials. The accomplished barrier layers will have lower resistivity on the via bottom in the first dielectric layer and they are capable of preventing copper atoms from diffusing into the dielectric layer.

1 . A method for forming a barrier layer, comprising:
 providing a conductive layer;   forming a first dielectric layer on the conductive layer, the first dielectric layer having a via therein;   forming a first barrier metal layer covering the first dielectric layer and the conductive layer;   forming a barrier layer of metalized materials on the first barrier metal layer;   removing portions of the barrier layer of metalized materials on the via bottom; and   forming a second barrier metal layer covering the barrier layer of metalized materials.   
   
   
       2 . The method for forming a barrier layer according to  claim 1 , wherein the step of removing portions of the barrier layer of metalized materials comprises leaving portions of the barrier layer of metalized materials on the via bottom and the barrier layer of metalized materials on the via sidewall. 
   
   
       3 . The method for forming a barrier layer according to  claim 1 , wherein the first barrier metal layer, the barrier layer of metalized materials and the second barrier metal layer are disposed on the via bottom and the whole via sidewall after the second barrier metal layer is formed. 
   
   
       4 . The method for forming a barrier layer according to  claim 1 , wherein the barrier layer of metalized materials on the via bottom in the first dielectric layer is removed by an ion-bombardment process. 
   
   
       5 . The method for forming a barrier layer according to  claim 4 , wherein metal atoms are bombarded out from the barrier layer of metalized materials toward the via sidewall. 
   
   
       6 . The method for forming a barrier layer according to  claim 4 , wherein the ion-bombardment process employs argon ions. 
   
   
       7 . The method for forming a barrier layer according to  claim 1 , further comprising forming a second dielectric layer on the first dielectric layer before forming the first barrier metal layer wherein a trench is in the second dielectric layer and the trench in the second dielectric layer is connected to the via in the first dielectric layer. 
   
   
       8 . The method for forming a barrier layer according to  claim 1 , wherein the first and the second barrier metal layers are tantalum layers, the barrier layer of metalized materials is a tantalum nitride layer, and the conductive layer is a copper layer. 
   
   
       9 . The method for forming a barrier layer according to  claim 1 , wherein the portions of the barrier layer of metalized materials disposed on the via bottom are thinner than the portions of the barrier layer of metalized materials disposed on the via sidewall. 
   
   
       10 . A method for forming a barrier layer, comprising;
 providing a conductive layer;   forming a first dielectric layer on the conductive layer, the first dielectric layer having a via therein;   forming a first barrier metal layer covering the first dielectric layer and the conductive layer;   forming a barrier layer of metalized materials on the first barrier metal layer;   forming a second barrier metal layer covering the barrier layer of metalized materials;   removing the second barrier metal layer and at least portions of the barrier layer of metalized materials on the via bottom; and   forming a third barrier metal layer covering the second barrier metal layer.   
   
   
       11 . The method for forming a barrier layer according to  claim 10 , wherein the step of removing the second barrier metal layer and the portions of the barrier layer of metalized materials comprises leaving the second barrier metal layer and the barrier layer of metalized materials remaining on the whole via sidewall. 
   
   
       12 . The method for forming a barrier layer according to  claim 10 , wherein the first barrier metal layer and the third barrier metal layer are disposed on the via bottom, and the first barrier metal layer, the barrier layer of metalized materials, the second barrier metal layer and the third barrier metal layer are disposed on the whole via sidewall. 
   
   
       13 . The method for forming a barrier layer according to  claim 10 , wherein the step of removing the second barrier metal layer and the portions of the barrier layer of metalized materials comprises leaving portions of the barrier layer of metalized materials on the via bottom and the second barrier metal layer and the barrier layer of metalized materials remaining on the whole via sidewall. 
   
   
       14 . The method for forming a barrier layer according to  claim 10 , wherein the first barrier metal layer, the barrier layer of metalized materials and the third barrier metal layer are disposed on the via bottom, and the first barrier metal layer, the barrier layer of metalized materials, the second barrier metal layer and the third barrier metal layer are disposed on the whole via sidewall. 
   
   
       15 . The method for forming a barrier layer according to  claim 10 , wherein the second barrier metal layer and the barrier layer of metalized materials on the via bottom in the first dielectric layer is removed by an ion-bombardment process. 
   
   
       16 . The method for forming a barrier layer according to  claim 15 , wherein metal atoms are bombarded out from the barrier layer of metalized materials toward the via sidewall. 
   
   
       17 . The method for forming a barrier layer according to  claim 15 , wherein the ion-bombardment process employs argon ions. 
   
   
       18 . The method for forming a barrier layer according to  claim 10 , further comprising forming a second dielectric layer on the first dielectric layer before forming the first barrier metal layer wherein a trench is in the second dielectric layer and the trench in the second dielectric layer is connected to the via in the first dielectric layer. 
   
   
       19 . A damascene structure, comprising:
 a conductive layer;   a first dielectric layer disposed on the conductive layer, the first dielectric layer having a via therein;   a first barrier metal layer disposed on the via bottom and the via sidewall in the first dielectric layer, the first barrier metal layer covering the conductive layer on the via bottom;   a barrier layer of metalized materials covering the first barrier metal layer on the via sidewall, exposing the first barrier metal layer on the via bottom;   a second barrier metal layer covering the barrier layer of metalized materials on the via sidewall, exposing the first barrier metal layer on the via bottom; and   a third barrier metal layer covering the second barrier metal layer on the via sidewall, and covering the first barrier metal layer on the via bottom.   
   
   
       20 . The damascene structure according to  claim 19 , wherein the first and the second barrier metal layers are tantalum layers, the barrier layer of metalized materials is a tantalum nitride layer, and the conductive layer is a copper layer.