Chemical Mechanical Polishing Slurry Composition for Polishing Phase-Change Memory Device and Method for Polishing Phase-Change Memory Device Using the Same

Abstract

A slurry composition for chemical mechanical polishing (CMP) of a phase-change memory device is provided. The slurry composition comprises deionized water and iron or an iron compound. The slurry composition can achieve high polishing rate on a phase-change memory device and improved polishing selectivity between a phase-change memory material and a polish stop layer (e.g., a silicon oxide film), can minimize the occurrence of processing imperfections (e.g., dishing and erosion), and can lower the etch rate on a phase-change memory material to provide a high-quality polished surface. Further provided is a method for polishing a phase-change memory device using the slurry composition.

1 . A slurry composition for chemical mechanical polishing (CMP) of a phase-change memory device in the absence of abrasive particles, comprising deionized water and iron or an iron compound, wherein the slurry composition does not include abrasive particles. 
   
   
       2 . The slurry composition according to  claim 1 , wherein the phase-change memory device comprises a metal alloy or a chalcogenide. 
   
   
       3 . The slurry composition according to  claim 2 , wherein the phase-change memory device comprises at least one compound selected from InSe, Sb 2 Te 3 , GeTe, Ge 2 Sb 2 Te 5 , InSbTe, GaSeTe, SnSb 2 Te 4 , InSbGe, AgInSbTe, (GeSn)SbTe, GeSb(SeTe) or Te 81 Ge 15 Sb 2 S 2 . 
   
   
       4 . The slurry composition according to  claim 1 , wherein the iron or iron compound comprises metal iron or a compound containing iron in its molecular structure. 
   
   
       5 . The slurry composition according to  claim 1 , wherein the iron or iron compound comprises an ionic iron compound or an iron chelate compound. 
   
   
       6 . The slurry composition according to  claim 1 , wherein the iron or iron compound is present in an amount of about 00.1 to about 10% by weight, based on the total weight of the slurry composition. 
   
   
       7 . The slurry composition according to  claim 1 , wherein the slurry composition has a pH of about 2 to about 10. 
   
   
       8 . The slurry composition according to  claim 1 , further comprising a pH-adjusting agent. 
   
   
       9 . The slurry composition according to  claim 8 , wherein the pH-adjusting agent comprises at least one acid selected from nitric acid, phosphoric acid, sulfuric acid, hydrochloric acid, organic carboxylic acids having a pKa of 6 or less, or a combination thereof. 
   
   
       10 . A method for polishing a phase-change memory device comprising a phase change layer, wherein the method comprises contacting said phase-change material layer in the absence of abrasive particles with a CMP slurry composition comprising deionized water and iron or an iron compound. 
   
   
       11 . The method according to  claim 10 , wherein the phase-change memory device is fabricated by applying an insulating material to a semiconductor wafer to form an insulating layer, planarizing the insulating layer, patterning the planar insulating layer, and applying a phase-change material to the patterned insulating layer to form a phase-change material layer; and the CMP slurry composition is brought into contact with the phase-change material layer to polish the phase-change material layer until the insulating layer is exposed. 
   
   
       12 . The method according to  claim 11 , wherein the phase-change material layer is polished by applying the CMP slurry composition to a rotating polishing pad and bringing the polishing pad into contact with the phase-change material layer under predetermined pressure conditions to polish portions of the phase-change material layer by a frictional force. 
   
   
       13 . A phase-change memory device polished by the method according to  claim 10 .