Apparatus and methods for acoustical monitoring and control of through-silicon-via reveal processing

Abstract

A TSV (through silicon via) reveal process using CMP (chemical mechanical polishing) may be acoustically monitored and controlled to detect TSV breakage and automatically respond thereto. Acoustic emissions received by one or more acoustic sensors positioned proximate a substrate holder and/or a polishing pad of a CMP system may be analyzed to detect TSV breakage during a CMP process. In response to detecting TSV breakage, one or more remedial actions may automatically occur. In some embodiments, a polishing pad platen may have one or more acoustic sensors integrated therein that extend into a polishing pad mounted on the polishing pad platen. Methods of monitoring and controlling a TSV reveal process are also provided, as are other aspects.

What is claimed is: 
     
         1 . A platen for a chemical mechanical polishing (CMP) apparatus, comprising:
 a disk-shaped base configured to receive a polishing pad on a surface thereof, the disk-shaped base having at least one through-hole; and   an acoustic sensor received in the at least one through-hole and protruding from the surface of the disk-shaped base, the acoustic sensor configured to be electrically coupled to a controller.   
     
     
         2 . The platen of  claim 1  further comprising a polishing pad mounted to the disk-shaped base, the polishing pad having a non-through hole on a base-side surface of the polishing pad configured to receive the acoustic sensor therein. 
     
     
         3 . The platen of  claim 1  wherein the at least one through-hole is positioned at about the center, or about 5 inches (about 12.7 cm) radially outward from the center, or about 10 inches (about 25.4 cm) radially outward from the center of the disk-shaped base. 
     
     
         4 . The platen of  claim 1  wherein the acoustic sensor protrudes from the surface of the disk-shaped base by about 50 mils (about 1.27 mm). 
     
     
         5 . Chemical mechanical polishing (CMP) apparatus configured to perform a CMP process, comprising:
 a platen comprising a polishing pad;   a substrate holder configured to hold a substrate to be polished, wherein the platen or the substrate holder is configured to put the substrate and the polishing pad in contact with each other;   an acoustic sensor positioned proximate the polishing pad or the substrate during the CMP process; and   an acoustic processor electrically coupled to the acoustic sensor and configured to analyze one or more signals received from the acoustic sensor to detect TSV (through silicon via) breakage.   
     
     
         6 . The CMP apparatus of  claim 5  wherein the acoustic processor is also configured to automatically stop the CMP process in response to detecting TSV breakage. 
     
     
         7 . The CMP apparatus of  claim 5  wherein the acoustic processor is also configured to automatically notify an operator in response to detecting TSV breakage. 
     
     
         8 . The CMP apparatus of  claim 5  wherein the acoustic processor is also configured to automatically modify the CMP process in response to detecting TSV breakage. 
     
     
         9 . The CMP apparatus of  claim 8  wherein the acoustic processor is configured to automatically modify the CMP process by reducing a down force, reducing a rotation speed, or both in response to detecting TSV breakage. 
     
     
         10 . The CMP apparatus of  claim 5  wherein the acoustic sensor comprises a flat frequency response over a region of about 100-500 kHz. 
     
     
         11 . The CMP apparatus of  claim 5  wherein the acoustic sensor amplifies an acoustic signal with a gain of about 40-60 dB. 
     
     
         12 . The CMP apparatus of  claim 5  wherein the acoustic sensor comprises a high pass filter having a range of about 50-100 Hz. 
     
     
         13 . The CMP apparatus of  claim 5  wherein the acoustic sensor is integrated in the platen such that the acoustic sensor protrudes from a surface of the platen into the polishing pad. 
     
     
         14 . The CMP apparatus of  claim 13  wherein the acoustic sensor protrudes from the surface of the platen by about 50 mils (about 1.27 mm). 
     
     
         15 . The CMP apparatus of  claim 5  wherein the acoustic sensor is integrated in the platen at about the center, or about 5 inches (about 12.7 cm) radially outward from the center, or about 10 inches (about 25.4 cm) radially outward from the center of the platen. 
     
     
         16 . A method of monitoring and controlling a through silicon via (TSV) reveal process, comprising:
 processing a substrate using a chemical mechanical polishing (CMP) process;   sensing acoustic emissions of the CMP process; and   analyzing the acoustic emissions to detect TSV breakage.   
     
     
         17 . The method of  claim 16  further comprising automatically stopping the CMP process in response to detecting TSV breakage. 
     
     
         18 . The method of  claim 16  further comprising automatically notifying an operator in response to detecting TSV breakage. 
     
     
         19 . The method of  claim 16  further comprising automatically modifying the CMP process in response to detecting TSV breakage. 
     
     
         20 . The method of  claim 19  wherein the automatically modifying comprises automatically modifying the CMP process by reducing a down force, reducing a rotation speed, or both in response to detecting TSV breakage.