Abstract: This application discloses a computing system to identify structures of an integrated circuit capable of being fabricated utilizing a lithographic mask described by mask layout data and to generate process windows for the identified structures based, at least in part, on the mask layout data and a failure definition for the identified structures. The computing system utilizes process windows for the identified structures to determine failure rates for the identified structures based on a distribution of the manufacturing parameters. The computing system determines frequency of occurrences for the identified structures from the mask layout data and generates a die yield metric for the integrated circuit by aggregating the failure rates for the identified structures based on the frequency of occurrences for the identified structures in the integrated circuit. These increases in yield of the integrated circuit allow manufacturers to produce more units per fixed processing cost of the wafer.

Abstract: This application discloses a computing system to identify structures of an integrated circuit capable of being fabricated utilizing a lithographic mask described by mask layout data and to generate process windows for the identified structures based, at least in part, on the mask layout data and a failure definition for the identified structures. The computing system utilizes process windows for the identified structures to determine failure rates for the identified structures based on a distribution of the manufacturing parameters. The computing system determines frequency of occurrences for the identified structures from the mask layout data and generates a die yield metric for the integrated circuit by aggregating the failure rates for the identified structures based on the frequency of occurrences for the identified structures in the integrated circuit. These increases in yield of the integrated circuit allow manufacturers to produce more units per fixed processing cost of the wafer.

Abstract: Systems and methods for calculating a printed area metric indicative of stochastic variations of the lithographic process are disclosed. Lithography is a process that uses light to transfer a geometric pattern from a photomask, based on a layout design, to a resist on a substrate. The lithographic process is subject to random stochastic phenomena, with the resulting stochastic randomness potentially becoming a major challenge. To characterize the stochastic phenomena, a printed area metric may be generated analytically (rather than via simulations) and comprise one or more defined moments for a printed area distribution associated with the printed area that are indicative of one or more aspects associated with printing. For example, the printed area metric may be indicative of the likelihood of printing within the printed area or the variance of printing within the printed area due to stochastic randomness in one or both of exposure or resist process.

Abstract: Systems and methods for calculating a printed area metric indicative of stochastic variations of the lithographic process are disclosed. Lithography is a process that uses light to transfer a geometric pattern from a photomask, based on a layout design, to a resist on a substrate. The lithographic process is subject to random stochastic phenomena, with the resulting stochastic randomness potentially becoming a major challenge. To characterize the stochastic phenomena, a printed area metric may be generated analytically (rather than via simulations) and comprise one or more defined moments for a printed area distribution associated with the printed area that are indicative of one or more aspects associated with printing. For example, the printed area metric may be indicative of the likelihood of printing within the printed area or the variance of printing within the printed area due to stochastic randomness in one or both of exposure or resist process.

Abstract: A method and system for calculating probability of success or failure for a lithographic process due to stochastic variations of the lithographic process are disclosed. Lithography is a process that uses light to transfer a geometric pattern from a photomask, based on a layout design, to a resist on a substrate. The lithographic process is subject to random stochastic phenomena, such as photon shot noise and stochastic phenomena in the resist process and resist development, with the resulting stochastic randomness potentially becoming a major challenge. The stochastic phenomena are modeled using a stochastic model, such as a random field model, that models stochastic randomness the exposure and resist process. The stochastic model inputs light exposure and resist parameters and definitions of success of success or failure as to the lithographic process, and outputs a probability distribution function of deprotection concentration indicative of success or failure probability of the lithographic process.

Abstract: Aspects of the disclosed technology relate to techniques for using hotspot simulation to make wafer rework decisions. Metrology data of photoresist patterns created based on a layout design for a circuit design by a photolithographic processing step are received during a lithographic process. Hotspots of interest are selected based on comparing the metrology data with simulated metrology data associated with hotspots. The simulated metrology data and information of the hotspots are generated by performing lithographic simulation on the layout design before the lithographic process and stored in a library of potential hotspots. Lithography simulation is performed on the selected hotspots of interest using process conditions of the photolithographic processing step to generate simulated hotspot data. The simulated hotspot data are analyzed to determine whether rework of the one or more wafers or a wafer lot to which the one or more wafers belong is needed.

Abstract: Aspects of the disclosed technology relate to techniques for using hotspot simulation to make wafer rework decisions. Metrology data of photoresist patterns created based on a layout design for a circuit design by a photolithographic processing step are received during a lithographic process. Hotspots of interest are selected based on comparing the metrology data with simulated metrology data associated with hotspots. The simulated metrology data and information of the hotspots are generated by performing lithographic simulation on the layout design before the lithographic process and stored in a library of potential hotspots. Lithography simulation is performed on the selected hotspots of interest using process conditions of the photolithographic processing step to generate simulated hotspot data. The simulated hotspot data are analyzed to determine whether rework of the one or more wafers or a wafer lot to which the one or more wafers belong is needed.

Abstract: Techniques for model calibration and alignment of measurement contours of printed layout features with simulation contours obtained with a model are disclosed. With various implementations of the invention, contour point errors are determined. Based on the contour point errors and a cost function, values of alignment parameters may be determined. The values of alignment parameters may be used to realign the measurement contours for model calibration. The alignment may be conducted concurrently with model calibration.

Abstract: Techniques for model calibration and alignment of measurement contours of printed layout features with simulation contours obtained with a model are disclosed. With various implementations of the invention, contour point errors are determined. Based on the contour point errors and a cost function, values of alignment parameters may be determined. The values of alignment parameters may be used to realign the measurement contours for model calibration. The alignment may be conducted concurrently with model calibration.

Abstract: Techniques for model calibration and alignment of measurement contours of printed layout features with simulation contours obtained with a model are disclosed. With various implementations of the invention, contour point errors are determined. Based on the contour point errors and a cost function, values of alignment parameters may be determined. The values of alignment parameters may be used to realign the measurement contours for model calibration. The alignment may be conducted concurrently with model calibration.

Abstract: Methods for determining tolerances are disclosed that can be used for determining whether a lot of semiconductor wafers needs to be reworked. Overlay tolerance, critical dimension tolerance and a dynamic line edge placement tolerance are determined using error measurements that are taken from sample wafers in the lot, giving tolerances that reflect the error state of that particular lot of semiconductor wafers.

Abstract: A method for generating a photoresist structure is disclosed in which a layer of photoresist is deposited over a semiconductor substrate. In a first exposure, the layer of photoresist is exposed to deep ultraviolet light. A second exposure is then performed using a different wavelength of light to pattern the layer of photoresist. The photoresist is then developed so as to form a photoresist structure having reduced thickness and rounded corners. This gives a photoresist structure having a reduced shadow area. An angled ion implant can then be performed using the photoresist structure as a mask.

Abstract: A method for forming a photoresist structure that does not have swelling defects. A layer of low activation energy deep ultraviolet photoresist is disposed over a layer that is to be patterned. A layer of high activation energy deep ultraviolet photoresist is then deposited such that the layer of high activation energy photoresist directly overlies the layer of low activation energy photoresist. The two photoresist layers are then processed by performing exposure, post-exposure bake, and development steps to form a photoresist structure. An etch step is then performed so as to form a patterned layer that does not have swelling defects.

Abstract: A method for generating a swing curve and a photoresist feature formed using the swing curve. A layer of photoresist is formed that has varying thickness. The thickness of the layer of photoresist is determined at a plurality of points. The semiconductor wafer is then exposed and developed to form a photoresist structure that includes features. For each of the points at which thickness was determined, the size of a corresponding feature is determined. A curve is then determined that correlates the thickness measurements and the size measurements. The resulting swing curve is then used to determine a thickness for photoresist deposition and a photoresist layer is deposited, exposed, and developed to obtain a photoresist feature having the desired size.

Abstract: In a photolithographic process utilizing a wafer coated with a chemically amplified photoresist, a method for controlling a line dimension. The method comprises the steps of measuring at at least two times, and from at least two angles, evolving signals comprising intensities of light diffracted from a portion of an exposed patterned area on the waver, the evolving signals corresponding to vector combinations of time dependent light diffracted from the pattern appearing in the photoresist; and substantially time invariant light diffracted due to any underlying pattern beneath the photoresist; and, combining the measurements mathematically for extracting a contribution due to the pattern evolving in the photoresist.