Two-line mixing of chemical and abrasive particles with endpoint control for chemical mechanical polishing

Abstract

Embodiments described herein provide a method for polishing a substrate surface. The methods generally include storing processing components in multiple storage units during processing, and combining the processing components to create a slurry while flowing the processing components to a polishing pad. A substrate is polished using the slurry, and the thickness of a material layer disposed on the substrate is determined. The flow rate of one or more processing components is then adjusted to affect the rate of removal of the material layer disposed on the substrate.

1 . A method for processing a semiconductor substrate surface, comprising:
 combining a first polishing component from a first storage unit and a polishing abrasive from a second storage unit while flowing the polishing abrasive and the first polishing component to a polishing pad, the polishing abrasive selected from the group consisting of colloidal silica, alumina, and ceria;   polishing a substrate with the polishing pad to remove at least a portion of a material layer disposed thereon;   measuring the thickness or uniformity of the material layer disposed on the substrate; and   adjusting the flow rate of the polishing abrasive or the first polishing component in response to the measured thickness or uniformity of the material layer to affect the removal rate of the material layer.   
   
   
       2 . The method of  claim 1 , wherein the substrate comprises a through-silicon via. 
   
   
       3 . The method of  claim 2 , wherein the first polishing component comprises an acid, a buffer, and an oxidizer. 
   
   
       4 . The method of  claim 3 , further comprising combining a second polishing component from a third storage unit with the polishing abrasive and the first polishing component while flowing the polishing abrasive, the first polishing component, and the second polishing component to the polishing pad. 
   
   
       5 . The method of  claim 4 , wherein the second polishing component comprises a corrosion inhibitor. 
   
   
       6 . The method of  claim 1 , wherein the flow rate of the first polishing component or the polishing abrasive is adjusted when the thickness of the material layer on the substrate is within a range from about 2,000 angstroms to about 4,000 angstroms. 
   
   
       7 . The method of  claim 6 , wherein the material layer comprises copper, and the thickness of the material layer removed from the substrate is within a range from about 4 micrometers to about 7 micrometers. 
   
   
       8 . The method of  claim 1 , wherein the polishing a substrate comprises incrementally reducing a polishing rate in response to the measured thickness of the material layer. 
   
   
       9 . A method for processing a semiconductor substrate surface, comprising:
 flowing a polishing slurry to a polishing pad, the polishing slurry comprising:   a polishing abrasive from a first storage unit; and   a polishing component from a second storage unit, the polishing component comprising an acid, an oxidizer, a corrosion inhibitor and a pH buffer;   polishing a substrate with the polishing pad at a first rate to remove at least a portion of a material layer disposed thereon;   measuring the thickness or uniformity of the material layer disposed on the substrate; and   adjusting the flow rate of the polishing abrasive in response to the measured thickness or uniformity of the material layer to affect the polishing rate.   
   
   
       10 . The method of  claim 9 , wherein the measuring the thickness or uniformity of the material layer is performed by spectrum based endpoint detection, optical endpoint detection, or charge, voltage or current measurement endpoint detection. 
   
   
       11 . The method of  claim 10 , wherein the rate of polishing the substrate decreases in response to the decreasing thickness of the material layer disposed on the substrate. 
   
   
       12 . The method of  claim 11 , wherein the material layer removed from the substrate has a thickness within a range from about 6 micrometers to about 8 micrometers. 
   
   
       13 . The method of  claim 9 , wherein a bulk material removal step and a residual material clear step are performed on the same platen. 
   
   
       14 . The method of  claim 13 , wherein the material layer comprises a conductive material. 
   
   
       15 . A method for processing a semiconductor substrate surface, comprising:
 combining a polishing abrasive from a first storage unit and a polishing component from a second storage unit while flowing the polishing abrasive and the polishing component to a polishing pad, the polishing abrasive selected from the group consisting of colloidal silica, alumina, and ceria, and the polishing component comprising an acid, an oxidizer, a corrosion inhibitor and a pH buffer;   polishing a substrate comprising a through-silicon via with the polishing pad to remove at least a portion of a material layer disposed on a substrate;   measuring the thickness or uniformity of the material layer disposed on the substrate; and   reducing the flow rate of the polishing abrasive in response to the decreasing measured thickness of the material layer, wherein the flow rate of the polishing component or the polishing abrasive is adjusted when the thickness of the material layer on the substrate is within a range from about 2,000 angstroms to about 4,000 angstroms.   
   
   
       16 . The method of  claim 15 , wherein the material layer comprises copper, and the thickness of the material layer removed from the substrate is within a range of about 4 micrometers to about 7 micrometers. 
   
   
       17 . The method of  claim 16 , wherein the polishing component comprises a corrosion inhibitor, and further wherein the flow rate of the corrosion inhibitor is increased as the thickness of the material layer disposed on the substrate decreases. 
   
   
       18 . The method of  claim 17 , wherein the measuring the thickness or uniformity of the material layer is performed by spectrum based endpoint detection, optical endpoint detection, or charge, voltage or current measurement endpoint detection. 
   
   
       19 . The method of  claim 15 , wherein the combining the polishing abrasive and the polishing component is accomplished by creating a helical or spiraling flow path within a single section of tubing to facilitate mixing of the polishing abrasive and the polishing component. 
   
   
       20 . The method of  claim 19 , wherein the polishing component comprises an acid, an oxidizer, a corrosion inhibitor and a pH buffer.