Multi-step planarizing and polishing method

Abstract

A multi-step planarizing and polishing method includes performing a first and a second polishing steps, wherein one of the two polishing steps is performed using a silica abrasive based slurry, while the other one of the two polishing steps is performed using a CeO 2 abrasive based slurry. A third polishing step is further performed using a fixed abrasive pad. Further, the thickness deviation of wafers entering the third polishing step is controlled.

1 . A planarizing and polishing method comprising:
 providing a substrate having a plurality of patterned features;   forming a material layer over the substrate and the patterned features;   planarizing the material layer with a first polishing slurry using a standard pad without embedded abrasive particles, wherein only silica abrasives is used as a first abrasives in the first polishing slurry;   planarizing the material layer with a second polishing slurry, wherein only CeO 2  (cerium oxide) abrasives is used as a second abrasives in the second polishing slurry; and   continuing to a final planarization of the material layer with a fixed abrasive pad, wherein a remaining thickness of the material layer entering the final planarization of the material layer is controlled.   
   
   
       2 . The method of  claim 1 , wherein the step of planarizing the material layer with the second polishing slurry is controlled by an end-point detection system. 
   
   
       3 . The method of  claim 1 , wherein the step of planarizing the material layer with the first polishing slurry removes a bulk of the material layer. 
   
   
       4 . The method of  claim 1 , wherein after the steps of planarizing the material layer with the first polishing slurry and the second polishing slurry, the remaining thickness of material layer is about 0 to 100Å. 
   
   
       5 . The method of  claim 1 , wherein the step of planarizing the material layer with the second polishing slurry is performed before the step of planarizing the material layer with the first polishing slurry. 
   
   
       6 . The method of  claim 5 , wherein the step of planarizing the material layer with the first polishing slurry is controlled by an endpoint detection mechanism. 
   
   
       7 . The method of  claim 1 , wherein the patterned features comprise french isolation structures. 
   
   
       8 . The method of  claim 1 , wherein the final planarization of the material layer with the fixed abrasive pad comprises a control of polishing time to avoid overpolishing. 
   
   
       9 . A planarizing and polishing method comprising:
 performing a first polishing step with a first slurry composition using a standard pad without embedded abrasive particles, wherein only silica abrasives is used as a first abrasives in the first polishing slurry;   performing a second polishing step with a second slurry composition, wherein only CeO 2  (Cerium Oxide) abrasives is used as a second abrasives in the second polishing slurry, and the second polishing step is controlled by an end-point detection mechanism; and   performing a third polishing step with a fixed abrasive pad.   
   
   
       10 . (canceled) 
   
   
       11 . The method of  claim 9 , wherein the second polishing step is performed using a standard pad without embedded abrasive particles. 
   
   
       12 . The method of  claim 9 , wherein the third polishing step is performed without slurry. 
   
   
       13 . A planarizing and polishing method comprising:
 performing a first polishing step with a first slurry composition and using a standard pad without embedded abrasive particles, wherein only CeO 2  abrasives is used as a first abrasives in the first slurry composition;   performing a second polishing step with a second slurry composition, wherein only silica abrasives is used as a second abrasives in the second slurry composition and the second polishing step is terminated by an end-point detection mechanism; and   performing a third polishing step with a fixed abrasive pad.   
   
   
       14 . (canceled) 
   
   
       15 . The method of  claim 13 , wherein the second polishing step is performed using a standard pad without embedded abrasive particles. 
   
   
       16 . The method of  claim 13 , wherein the third polishing step is performed without slurry. 
   
   
       17 . A multi-step planarizing and polishing method comprising:
 providing a structure having a nonplanar surface topography;   performing at least two polishing steps with two different slurry compositions, wherein a removal rate of one of the two polishing steps is higher than that of the other polishing step a first polishing step with a first slurry composition comprising at least silica abrasives and a first polishing step of the two polishing steps using a standard pad without embedded abrasive particles;   controlling a remaining thickness of the structure at an end of the two polishing steps; and   performing a final polishing step with a fixed abrasive pad.   
   
   
       18 . The method of  claim 17 , wherein one of the two slurry compositions comprises at least CeO 2  abrasives. 
   
   
       19 . The method of  claim 17 , wherein one of the two slurry compositions comprises at least silica abrasives. 
   
   
       20 . The method of  claim 17 , wherein the two polishing steps use different polishing pads. 
   
   
       21 . The method of  claim 17 , wherein the two polishing steps use a same polishing pad. 
   
   
       22 . The method of  claim 21 , wherein the two polishing steps use a standard pad without embedded abrasive particles. 
   
   
       23 . The method of  claim 17 , wherein at least one of the two polishing steps is controlled by an end-point detection method to control the remaining thickness of the structure.