Optical techniques of measuring endpoint during the processing of material layers in an optically hostile environment

Claim 2

A process of planarizing or polishing a first side of a structure, comprising the steps of: holding the structure by contact with a second side thereof, moving the first side of said substrate across an abrasive medium, optically monitoring a temperature of the structure, and detecting from changes in said temperature when said planarizing or polishing process is completed.

Claim 5

The method according to claim 1 which comprises the additional steps of: positioning second light gathering optics with respect to the surface and the radiation beam directed thereagainst in order to receive a portion of the beam scattered from the surface when the surface is in the rough state but substantially none of the beam from the surface when the surface is in the smooth state, during the polishing process, monitoring an intensity level of said beam portion scattered from the surface, and determining when the intensity level of the received scattered beam portion stops dropping, thereby to determine that the polishing is complete.

Claim 6

During a process of chemically and mechanically removing material from a surface of a front side of a substrate that has a back side held by a first member and the front side surface urged against a second member with an abrasive slurry therebetween while relative motion is imparted to the first and second members, a method of monitoring the material removal process, comprising: directing radiation through the first member against the back side of the substrate, said radiation including a wavelength to which the substrate is transparent, said radiation thereby passing through said substrate to its front side, detecting a portion of said radiation that is reflected from the substrate front side and travels back through the substrate and the first member, and monitoring the detected radiation portion, thereby to monitor the material removal process as it is occurring.

Claim 7

During a process of chemically and mechanically removing material from a surface of a front side of a substrate that has a back side held by a first member and the front side surface urged against a second member with an abrasive slurry therebetween while relative motion is imparted to the first and second members, a method of monitoring the material removal process, comprising: directing radiation through the first member against the back side of the substrate, said radiation including a wavelength to which the substrate is transparent, said radiation thereby passing through said substrate to its front side, detecting a portion of said radiation that is reflected from the substrate front side and travels back through the substrate and the first member, and monitoring the detected radiation portion, thereby to monitor the material removal process as it is occurring.

Claim 8

The method of claim 4 wherein the process is removing material from a layer carried by the front side of the substrate, and the monitoring method monitors the removal of such material from the layer.

Claim 9

The method of claim 5 which additionally comprises identifying a characteristic of the monitored detected radiation portion that corresponds to the existence of a particular condition of the material removal process.

Claim 10

The method of claim 6 wherein the process includes removing material from a layer of material that is opaque to said radiation, and wherein the characteristic recognized is the total removal of the layer across at least a portion of a surface area of the layer.

Claim 11

The method of claim 6 wherein the process includes removing material from a layer of material that is transparent to said radiation, and wherein the characteristic recognized is the total removal of the layer across at least a portion of a surface area of the layer.

Claim 12

The method of claim 6 wherein the process includes removing material from a layer of material that is transparent to said radiation, and wherein the monitoring of the detected radiation includes monitoring a varying intensity of an interference between two portions of the detected radiation, one of said portions being reflected from an outer surface of the layer, and recognizing from the varying intensity a change in thickness of the layer.

Claim 13

The method of claim 6 wherein the identified characteristic of the monitored detected radiation portion includes a rapid change in a level of intensity of the detected radiation portion.

Claim 14

The method of claim 6 wherein the identified characteristic of the monitored detected radiation portion includes a change in a periodically varying intensity of the detected radiation portion.

Claim 15

The method of claim 11 wherein the change in the periodically varying intensity of the detected radiation portion being monitored is a cessation of periodic variations in the intensity of the detected radiation portion.

Claim 16

The method of claim 6 wherein the radiation directed against the substrate includes multiple wavelengths of radiation and the identified characteristic of the monitored detected radiation portion includes a wavelength spectrum of the detected radiation portion.

Claim 21

A process of chemically and mechanically removing material from a layer of opaque material carried by a front side of a substrate in the form of either a semiconductor wafer or a flat panel display, wherein the substrate has a back side held by a carrier and the layer urged against a polishing block with an abrasive slurry therebetween while relative motion is imparted between the carrier and the polishing block, wherein the removal of material is monitored in real time by a method comprising: directing a beam of radiation through the carrier against the back side of the substrate, said radiation including a wavelength to which the substrate is transparent, said radiation thereby passing through said substrate to said layer, detecting a portion of said radiation that is reflected from the layer and travels back through the substrate and the carrier, monitoring the level of the detected radiation portion, thereby to monitor the material removal process as it is occurring, and identifying a characteristic of the monitored detected radiation portion that corresponds to the existence of a particular condition of the material removal process.

Claim 22

A process of chemically and mechanically removing material from a layer of opaque material carried by a front side of a substrate in the form of either a semiconductor wafer or a flat panel display, wherein the substrate has a back side held by a carrier and the layer urged against a polishing block with an abrasive slurry therebetween while relative motion is imparted between the carrier and the polishing block, wherein the removal of material is monitored in real time by a method comprising: directing a beam of radiation through the carrier against the back side of the substrate, said radiation including a wavelength to which the substrate is transparent, said radiation thereby passing through said substrate to said layer, detecting a portion of said radiation that is reflected from the layer and travels back through the substrate and the carrier, monitoring the level of the detected radiation portion, thereby to monitor the material removal process as it is occurring, and identifying a characteristic of the monitored detected radiation portion that corresponds to the existence of a particular condition of the material removal process.

Claim 23

The process of claim 18 wherein the characteristic that is identified corresponds to the existence of a total removal of the layer across at least a portion of a surface area thereof.

Claim 24

The process of claim 19 additionally comprising, in response to the identification of the total removal of the layer across at least a portion of a surface area thereof, termination of any further removal of material from the layer.

Claim 25

The method of claim 18 wherein the identified characteristic of the monitored detected radiation portion includes a rapid change in a level of intensity of the detected radiation portion.

Claim 26

The process according to any one of claims 18-21 wherein the radiation is electromagnetic radiation that is passed through the carrier by way of an optical element carried by the carrier.

Claim 27

The process according to claim 22 wherein the optical element is held in contact with the back side of the substrate.

Claim 28

The process according to any one of claims 18-21 wherein at least the carrier is rotated during the process.

Claim 29

A process of chemically and mechanically removing material from a layer of transparent material carried by a front side of a substrate in the form of either a semiconductor wafer or a flat panel display, wherein the substrate has a back side held by a carrier and the layer urged against a polishing block with an abrasive slurry therebetween while at least the carrier is moved with respect to the polishing block, wherein the removal of material is monitored in real time by a method comprising: directing a beam of radiation through the carrier against the back side of the substrate, said radiation including a wavelength to which the substrate is transparent as well as said layer, said radiation thereby passing through said substrate to said layer and portions thereof being partially reflected from various interfaces and back through the substrate and the first member, detecting at least two of said reflected radiation portions, one of which is reflected from an exterior surface of the layer, said radiation detection occurring after the radiation has traveled from the layer back through the substrate and the first member, monitoring a resulting interference between the detected at least two of said reflected radiation portions, thereby to optically monitor progress of the removal of material from the layer, and identifying a characteristic of the monitored radiation interference that corresponds to the existence of a particular condition of the material removal process.

Claim 30

A process of chemically and mechanically removing material from a layer of transparent material carried by a front side of a substrate in the form of either a semiconductor wafer or a flat panel display, wherein the substrate has a back side held by a carrier and the layer urged against a polishing block with an abrasive slurry therebetween while at least the carrier is moved with respect to the polishing block, wherein the removal of material is monitored in real time by a method comprising: directing a beam of radiation through the carrier against the back side of the substrate, said radiation including a wavelength to which the substrate is transparent as well as said layer, said radiation thereby passing through said substrate to said layer and portions thereof being partially reflected from various interfaces and back through the substrate and the first member, detecting at least two of said reflected radiation portions, one of which is reflected from an exterior surface of the layer, said radiation detection occurring after the radiation has traveled from the layer back through the substrate and the first member, monitoring a resulting interference between the detected at least two of said reflected radiation portions, thereby to optically monitor progress of the removal of material from the layer, and identifying a characteristic of the monitored radiation interference that corresponds to the existence of a particular condition of the material removal process.

Claim 31

The process of claim 25, additionally comprising, in response to detecting said characteristic, generating a signal.

Claim 32

The process of claim 26, additionally comprising, in response to the signal, of altering the material removal process.

Claim 33

The process of claim 27 wherein altering the material removal process includes terminating further removal of material from the layer.

Claim 34

The method of claim 25 wherein the identified characteristic of the monitored interference includes a change in a periodically varying intensity of the interference.

Claim 35

The method of claim 29 wherein the change in the periodically varying intensity of the interference being monitored is a cessation of periodic variations in the intensity of the interference.

Claim 36

The process according to any one of claims 25-30 wherein the radiation is electromagnetic radiation that is passed through the carrier by way of an optical element carried by the carrier.

Claim 37

The process according to claim 31 wherein the optical element is held in contact with the back side of the substrate.

Claim 38

In a chemical-mechanical planarization apparatus that includes a carrier with a surface capable of holding a backside of a substrate thereagainst and which provides relative movement of a front side of the substrate against a polishing block with an abrasive slurry therebetween, a system that monitors removal of material from the front side of the substrate, said system comprising: a source of electromagnetic radiation, at least one optical element that is transparent to said radiation and which is embedded in the surface of said carrier in a position adjacent a backside of a substrate carried thereby, an optical system positioned to direct said radiation through the optical element and a substrate held against the carrier surface, a photodetector positioned to receive, through said at least one optical element, radiation that is reflected from a front side of said substrate, thereby to,generate an electrical signal related to the reflected radiation, means receiving the electrical signal for identifying a particular characteristic of the electrical signal that corresponds to a predefined condition of the wafer front side, and means responsive to an identification of the particular characteristic for changing some aspect of operation of the apparatus.

Claim 39

In a chemical-mechanical planarization apparatus that includes a carrier with a surface capable of holding a backside of a substrate thereagainst and which provides relative movement of a front side of the substrate against a polishing block with an abrasive slurry therebetween, a system that monitors removal of material from the front side of the substrate, said system comprising: a source of electromagnetic radiation, at least one optical element that is transparent to said radiation and which is embedded in the surface of said carrier in a position adjacent a backside of a substrate carried thereby, an optical system positioned to direct said radiation through the optical element and a substrate held against the carrier surface, a photodetector positioned to receive, through said at least one optical element, radiation that is reflected from a front side of said substrate, thereby to,generate an electrical signal related to the reflected radiation, means receiving the electrical signal for identifying a particular characteristic of the electrical signal that corresponds to a predefined condition of the wafer front side, and means responsive to an identification of the particular characteristic for changing some aspect of operation of the apparatus.

Claim 40

The system of claim 33 wherein the characteristic identifying means includes means for identifying an end point of the processing and the operation changing means includes means for terminating operation of the apparatus.

Claim 43

The method according to claim 35 wherein material is removed from the exterior surface by holding the substrate of the layered structure in a manner to position the exterior surface against a polishing block with a chemical-mechanical slurry therebetween, and providing relative motion between said exterior surface and the polishing block.

Claim 44

The method according to claim 35 wherein monitoring the interference includes monitoring an alternating intensity resulting from interference between the partial reflections from the exterior surface and at least one of the boundary surfaces.

Claim 45

The method according to claim 35 which additionally comprises detecting a characteristic of the intensity component being monitored and, in response to detecting said characteristic, altering the material removal process on said layer exterior surface.

Claim 48

The method according to claim 39 wherein material is removed from the exterior surface by holding the substrate of the layered structure in a manner to position the exterior surface against a planar surface with an abrasive material therebetween, and providing relative motion between said exterior and planar surfaces.

Claim 49

The method according to claim 39 wherein monitoring the reflected radiation includes monitoring an alternating intensity component resulting from interference between reflections from the exterior surface and at least one of the boundary surfaces.

Claim 50

The method according to claim 41 wherein the alternating intensity component results primarily from interference with reflections from the raised areas of the exterior surface.

Claim 51

The method according to claim 41 wherein the alternating intensity component results primarily from interference with reflections from the depressed areas of the exterior surface.

Claim 52

The method according to claim 39 wherein monitoring a component of the reflected radiation includes primarily monitoring an intensity component resulting from interference with reflections from the raised areas of the exterior surface.

Claim 53

The method according to claim 39 wherein monitoring an component of the reflected radiation includes primarily monitoring an intensity component resulting from interference with reflections from the depressed areas of the exterior surface.

Claim 54

The method according to claim 39 which additionally comprises detecting a characteristic of the intensity component being monitored and, in response to detecting said characteristic, altering the material removal process on said layer exterior surface.