Device for measuring the profile of a metal film sputter deposition target, and system and method employing same

Abstract

An apparatus and method for measuring the erosion profile of a metallic target in a sputtering device are provided by inserting a thin sensor into a gap between the target and a substrate pedestal. The sensor is configured to emit an energy beam toward the surface of the target and to detect a reflection of the energy beam. The sensor may comprise a source element configured to emit a collimated light beam and a plurality of detectors arranged in a linear array. The sensor may also comprise optical fibers configured to reduce the size of the sensor. The detectors are positioned relative to the source element so that one of the detectors in the array will be illuminated by a reflection of the collimated light beam. The distance from the sensor to the target may be derived from the position of the detector illuminated by the reflected beam.

1 . A sputtering apparatus, comprising: 
 a chamber;    a sputtering target located within the chamber; and    a sensor associated with the chamber and configured to measure at least one characteristic of a target surface of the sputtering target, wherein the sensor comprises: 
 a source element configured to project an energy beam onto the target surface of the sputtering target; and  
 a plurality of detectors disposed in a linear array and configured to detect a reflection of the energy beam from the surface of the sputtering target.  
   
     
     
         2 . The apparatus of  claim 1 , wherein the at least one characteristic comprises an erosion profile of the target surface.  
     
     
         3 . The apparatus of  claim 1 , wherein each of the plurality of detectors is configured to generate an electronic sensory signal related to an angle of the reflection of the energy beam incident thereon.  
     
     
         4 . The apparatus of  claim 1 , wherein each of the plurality of detectors comprises a collimator configured to collect the reflection of the energy beam incident thereon into a corresponding optical fiber.  
     
     
         5 . The apparatus of  claim 4 , further comprising a receiver optically coupled to each collimator through its corresponding optical fiber, the receiver configured to generate an electronic sensory signal for each collimator related to an angle of the reflection of the energy beam incident thereon.  
     
     
         6 . The apparatus of  claim 1 , wherein the energy beam is a collimated light beam.  
     
     
         7 . The apparatus of  claim 1 , wherein the source element comprises a collimator configured to collimate the energy beam as it exits an optical fiber.  
     
     
         8 . The apparatus of  claim 7 , further comprising a transmitter optically coupled to the source element through the optical fiber, the transmitter configured to transmit the energy beam to the collimator.  
     
     
         9 . The apparatus of  claim 1 , wherein the plurality of detectors comprises a first detector located in relation to the source element so as to be illuminated by the reflection of the energy beam when substantially none of the target surface at a target surface location is eroded.  
     
     
         10 . The apparatus of  claim 9 , wherein the plurality of detectors comprises a second detector located in relation to the source element so as to be illuminated by the reflection of the energy beam when substantially all of the target surface at the target surface location is eroded.  
     
     
         11 . The apparatus of  claim 10 , wherein the plurality of detectors comprises at least one intermediate detector positioned between the first detector and the second detector with a proportional distance relationship to the first detector and the second detector, and located in relation to the source element so as to be illuminated by the reflection of the energy beam when the target surface at the target surface location is partially eroded such that the proportional distance relationship correlates to the partially eroded amount.  
     
     
         12 . A sputtering erosion sensor, comprising: 
 a sensor configured to emit an energy beam toward a target surface of a sputtering target and to detect a reflection of the energy beam from the target surface; and    a transporter configured to detachably bear the sensor and transport the sensor relative to the target surface.    
     
     
         13 . The sensor of  claim 12 , wherein the transporter is further configured as a substrate pickup arm configured to pick up and place a substrate on a pedestal.  
     
     
         14 . The sensor of  claim 13 , wherein the substrate pickup arm includes a pickup device selected from the group consisting of a clamp, a vacuum chuck, and an electrostatic chuck.  
     
     
         15 . The sensor of  claim 12 , wherein the transporter is an articulating arm configured for attachment to a robot.  
     
     
         16 . The sensor of  claim 12 , wherein the transporter is further configured to transport the sensor substantially parallel to the target surface along a substantially linear path between substantially a center of the target and substantially an outer edge of the target.  
     
     
         17 . The sensor of  claim 12 , wherein the sensor comprises a source element configured to emit the energy beam and a plurality of detectors disposed in a linear array.  
     
     
         18 . The sensor of  claim 17 , wherein the plurality of detectors comprises a first detector located in relation to the source element so as to be illuminated by the reflection of the energy beam when substantially none of the target surface at a target surface location is eroded.  
     
     
         19 . The sensor of  claim 18 , wherein the plurality of detectors comprises a second detector located in relation to the source element so as to be illuminated by the reflection of the energy beam when substantially all of the target surface at the target surface location is eroded.  
     
     
         20 . The sensor of  claim 19 , wherein the plurality of detectors comprises at least one intermediate detector positioned between the first detector and the second detector with a proportional distance relationship to the first detector and the second detector, and located in relation to the source element so as to be illuminated by the reflection of the energy beam when the target surface at the target surface location is partially eroded such that the proportional distance relationship correlates to the partially eroded amount.  
     
     
         21 . A method of measuring at least one sputtering characteristic, comprising: 
 providing a sputtering target within a chamber;    providing a sensor within the chamber, the sensor comprising a source element and a plurality of detectors disposed in a linear array;    directing an energy beam from the source element onto a target surface of the sputtering target; and    detecting a reflection of the energy beam from the target surface of the sputtering target with at least one detector of the plurality of detectors.    
     
     
         22 . The method of  claim 21 , wherein the at least one sputtering characteristic comprises an erosion amount of the sputtering target.  
     
     
         23 . The method of  claim 21 , further comprising estimating an erosion amount of the target surface at a target surface location by measuring a time delay between emitting the energy beam and detecting the reflection of the energy beam.  
     
     
         24 . The method of  claim 21 , further comprising estimating an erosion amount of the target surface at a target surface location by measuring a phase difference between the energy beam and the reflection of the energy beam.  
     
     
         25 . The method of  claim 21 , further comprising estimating an erosion amount of the target surface at a target surface location by comparing a power level of the energy beam with a power level of the reflection of the energy beam.  
     
     
         26 . The method of  claim 21 , further comprising estimating an erosion amount of the target surface at a target surface location by detecting a location on the sensor illuminated by the reflection of the energy beam by using the plurality of detectors disposed in the linear array.  
     
     
         27 . A method of developing a sputtering erosion profile, comprising: 
 transporting a sensor near a target surface location along a substantially linear path between substantially a center of a sputtering target and substantially an outer edge of the sputtering target;    illuminating the target surface location with an energy beam emitted from a source element born by the sensor;    detecting a reflection of the energy beam from a surface of the sputtering target at the target surface location with at least one detector born by the sensor; and    repeating the transporting, illuminating, and detecting for at least one additional target surface location along the substantially linear path to develop a sputtering erosion profile.    
     
     
         28 . The method of  claim 27 , further comprising estimating an erosion amount of the target surface at the target surface location by measuring a time delay between emitting the energy beam and detecting the reflection of the energy beam.  
     
     
         29 . The method of  claim 27 , further comprising estimating an erosion amount of the target surface at the target surface location by measuring a phase difference between the energy beam and the reflection of the energy beam.  
     
     
         30 . The method of  claim 27 , further comprising estimating an erosion amount of the target surface at the target surface location by comparing a power level of the energy beam with a power level of the reflection of the energy beam.  
     
     
         31 . The method of  claim 27 , further comprising estimating an erosion amount of the target surface at the target surface location by detecting a location on the sensor illuminated by the reflection of the energy beam by using a plurality of detectors disposed in a linear array.