Litel Instruments

Other

Lael Instruments

Bruce B McArthur

Adlai H Smith

Robert O Hunter, Jr

Clark C Guest

Thomas K Khuu

Yuji Yamaguchi

Jim Wilkinson

Steven Blair

Intra-field distortion for a projection imaging tool is determined using a self-referenced rectangular grid reticle pattern, that includes at least two arrays of alignment attributes that are complementary to each other, is exposed multiple times onto a substrate with a recording media. A reference reticle pattern is exposed onto the substrate, wherein the reference reticle pattern overlaps the grid alignment attributes thereby creating completed grid alignment attributes. Positional offsets of the completed alignment attributes and completed grid alignment attributes are measured and an intra-field distortion from the offsets is determined.

Method and apparatus for self-referenced wafer stage positional error mapping

A wafer stage overlay error map is created using standard overlay targets and a special numerical algorithm. A reticle including a 2-dimensional array of standard overlay targets is exposed several times onto a photoresist coated silicon wafer using a photolithographic exposure tool. After exposure, the overlay targets are measured for placement error using a conventional overlay metrology tool. The resulting overlay error data is then supplied to a software program that generates a 2-dimensional wafer stage distortion and yaw overlay error map.

A method and apparatus for front to back substrate registration is described. Alignment characteristics of features on surfaces of substrates can be used to physically align substrates with a multiplicity of integrated alignment optics. Measurement of offsets of the integral alignment optics are used to compute registration data for use in calibration of the substrate global alignment.

Method and apparatus for registration with integral alignment optics

Techniques for determining wafer stage grid and yaw in a projection imaging tool are described. The techniques include exposing an overlay reticle onto a substrate having a recording media, thereby creating a plurality of printed fields on the substrate. The overlay reticle is then positioned such that when the reticle is exposed again completed alignment attributes are created in at least two sites in a first and a second printed field. The substrate is then rotated relative to the reticle by a desired amount. The overlay reticle is then positioned such that when the reticle is again exposed, completed alignment attributes are created in at least two sites in the first and a third printed field. Measurements of the complementary alignment attribute and a dynamic intra-field lens distortion are then used to reconstruct wafer stage grid and yaw error of the projection imaging system.

Method and apparatus for self-referenced dynamic step and scan intra-field scanning distortion

An apparatus and method for manufacturing and using a calibrated registration reference wafer in a semiconductor manufacturing facility. A reference reticle consisting of a 2-dimensional array of standard alignment attributes is exposed several times onto a photoresist coated semiconductor wafer using a photolithographic exposure tool. After the final steps of the lithographic development process the resist patterned wafer is physically etched using standard techniques to create a permanent record of the alignment attribute exposure pattern. The permanently recorded alignment attributes are measured for placement error using a conventional overlay metrology tool. The resulting overlay error data is used to generate a calibration file that contains the positions of the alignment attributes on the reference wafer. The reference wafer and calibration file can be used to determine the wafer stage registration performance for any photolithographic exposure tool.

Reference wafer and process for manufacturing same

A reticle stage grid and yaw in a projection imaging tool is determined by exposing a first portion of a reticle pattern onto a substrate with a recording media thereby producing a first exposure. The first portion of the reticle pattern includes at least two arrays of alignment attribute that have features complementary to each other. The reticle stage is then shifted and a second portion of the reticle pattern is exposed. The first and second exposures overlap and interlock to create completed alignment attributes. Measurements of positional offsets of the completed alignment attributes are used to determine the reticle stage grid and yaw.

Method and apparatus for self-referenced dynamic step and scan intra-field lens distortion

A projection lens distortion error map is created using overlay targets and a special numerical algorithm. A reticle including an array of overlay targets is exposed several times onto a photoresist coated silicon wafer using a photolithographic stepper. After exposure, the overlay targets are measured for placement error. The resulting overlay error data is then supplied to a software program that generates a lens distortion error map for the photolithographic projection system.

Method and apparatus for self-referenced projection lens distortion mapping

An in-situ apparatus for high resolution imaging in lithographic steppers and scanners (machines) is described. It comprises a multiple field in-situ imaging objective that images the source directly onto the machine reticle or objective plane. The image on the wafer side of the machine is then recorded electronically or in photo resist. Alternative embodiments create source images at locations before or beyond the wafer plane that can be more conveniently recorded with sensors embedded in the wafer stage chuck.

Apparatus and method for high resolution in-situ illumination source measurement in projection imaging systems

A photomask or reticle including a unique set of alignment attributes at separate and distinguishable field points is put in the reticle plane of a photolithographic projection system. The reticle pattern is exposed onto a resist coated wafer or substrate and processed through the final few steps of the photolithographic process. The resulting array of alignment attributes are then measured using a standard optical overlay metrology tool. The overlay tool is driven by a set of software instructions. By comparing the resulting overlay data to the placement error encoded on the reticle it can determined if the data has been read or displayed in the correct order.

Method and apparatus for proper ordering of registration data

A process of measuring the radiant intensity profile of an effective source of a projection image system that has an effective source, an object plane, an imaging objective, an exit pupil, and an image plane. The improved process consists of selecting at least one field point and a corresponding aperture plane aperture and projecting a plurality of images of the selected field point through the corresponding selected aperture plane aperture at a plurality of various intensities of the effective source. By analyzing the recorded images of the effective source at various intensities it is possible to determine a radiant intensity profile of the image source at the selected field point.

In-situ source metrology instrument and method of use

A projection lens distortion error map is created using standard overlay targets and a special numerical algorithm. A reticle including a 2-dimensional array of standard overlay targets is exposed several times onto a photoresist coated silicon wafer using a photolithographic stepper. After exposure, the overlay targets are measured for placement error using a conventional overlay metrology tool. The resulting overlay error data is then supplied to a software program that generates a lens distortion error map for the photolithographic projection system.

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San Diego, CA, United States of America

Bruce B McArthur