Optical techniques of measuring endpoint during the processing of material layers in an optically hostile environment
First Claim
1. A method of removing at least a portion of a layer that is carried on a first side of a substrate, comprising:
- applying a material removing substance to an exposed surface of said layer but not to a second side of the substrate opposite said first side, said substance being characterized by modifying electromagnetic radiation incident thereon, whereby material is removed from said layer exposed surface but not from the second side of the substrate,directing a first beam of electromagnetic radiation against said second side of the substrate to said layer through said substrate, said first beam of electromagnetic radiation including a wavelength band to which each of said substrate and said layer is substantially transparent,receiving and detecting a second beam of electromagnetic radiation within said wavelength band that is a portion of said first beam that exits the second substrate side after reflection at boundary surfaces of said layer and said substrate, andconcurrently with material being removed from the exposed surface of the layer, monitoring a varying intensity of a component of the detected second beam which results from an interference between portions of the first beam reflected from said exposed surface and an underlying boundary surface.
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Accused Products
Abstract
In a process of selectively removing material from an exposed layer carried by a substrate, a technique for determining endpoint by monitoring the intensity of a radiation beam that is passed through the substrate and any intervening layers to be reflected off the layer being processed. This monitoring technique is used during photoresist developing, wet etching, and mechanical planarization and polishing during the manufacture of integrated circuits on semiconductor wafers, flat panel displays on glass substrates, and similar articles. Planarization and polishing processes are alternatively monitored by monitoring temperature.
134 Citations
23 Claims
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1. A method of removing at least a portion of a layer that is carried on a first side of a substrate, comprising:
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applying a material removing substance to an exposed surface of said layer but not to a second side of the substrate opposite said first side, said substance being characterized by modifying electromagnetic radiation incident thereon, whereby material is removed from said layer exposed surface but not from the second side of the substrate, directing a first beam of electromagnetic radiation against said second side of the substrate to said layer through said substrate, said first beam of electromagnetic radiation including a wavelength band to which each of said substrate and said layer is substantially transparent, receiving and detecting a second beam of electromagnetic radiation within said wavelength band that is a portion of said first beam that exits the second substrate side after reflection at boundary surfaces of said layer and said substrate, and concurrently with material being removed from the exposed surface of the layer, monitoring a varying intensity of a component of the detected second beam which results from an interference between portions of the first beam reflected from said exposed surface and an underlying boundary surface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A process of removing material carried by a first side of a substrate that is held for processing, comprising the steps of:
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placing the first side of the substrate in contact with a material removing substance, directing through a second side of the substrate and against said material an electromagnetic radiation beam having a wavelength band to which said substrate and said material are substantially transparent, and detecting a particular characteristic of the state of the material removal process from a component of the radiation beam reflected from said material through said second substrate side, said component having an intensity which varies over time from interference between portions of the radiation beam reflected from different boundary surfaces as said material is being removed. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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21. A process of removing material from a layer carried by a first side of a substrate, comprising:
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applying material removing fluid to said layer from said first substrate side in a manner wherein fluid that attenuates or scatters electromagnetic radiation exists adjacent to said layer but not adjacent to a second side of the substrate, directing to said layer through said second side of the substrate an electromagnetic radiation beam having a wavelength band to which said substrate and layer are substantially transparent, and detecting a particular characteristic of the state of the material removal process from a component of the radiation beam reflected from the layer and exiting the second substrate side, said detecting including determining when an alternating intensity component of the reflected radiation beam ends. - View Dependent Claims (22, 23)
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Specification