摘要:
In accordance with some embodiments, a method is provided for creating a photolithographic component, comprising: determining a target pattern for a circuit layout, the target pattern comprising target features; identifying a set of periodic target features within the target pattern; calculating a relationship between feature and pitch for the set of periodic target features; and determining a mask pattern from the target pattern using the relationship, wherein the mask pattern has a set of periodic mask features configured to result in projection of a first subset of the set of periodic target features when exposed to a light source that induces a first phase effect, and configured to result in projection of a second subset of the set of periodic target features when exposed to a light source that induces a second phase effect. In further embodiments, the method outputs the mask pattern as a mask dataset.
摘要:
Improvements in the fabrication of integrated circuits are driven by the decrease of the size of the features printed on the wafers. Current lithography techniques limits have been extended through the use of phase-shifting masks, off-axis illumination, and proximity effect correction. More recently, liquid immersion lithography has been proposed as a way to extend even further the limits of optical lithography. This invention described a methodology based on contact or proximity printing using a projection lens to define the image of the mask onto the wafer. As the imaging is performed in a solid material, larger refractive indices can be obtained and the resolution of the imaging system can be increased.
摘要:
Systems and methods of semiconductor device fabrication and layout generation are disclosed. An exemplary method includes processes of depositing a layer of a first material and patterning the layer to form an initial pattern, wherein the initial pattern defines critical features of the layout elements using a single exposure; depositing spacer material over the first pattern on the substrate and etching the spacer material such that the spacer material is removed from horizontal surfaces of the substrate and the first pattern but remains adjacent to vertical surfaces of the first pattern; removing the initial pattern from the substrate while leaving the spacer material in a spacer pattern; filling the spacer pattern with final material; and trimming the filled pattern to remove portions of the final material beyond dimensions of the layout elements.
摘要:
Systems and methods of semiconductor device fabrication and layout generation are disclosed. An exemplary method includes processes of depositing a layer of a first material and patterning the layer to form an initial pattern, wherein the initial pattern defines critical features of the layout elements using a single exposure; depositing spacer material over the first pattern on the substrate and etching the spacer material such that the spacer material is removed from horizontal surfaces of the substrate and the first pattern but remains adjacent to vertical surfaces of the first pattern; removing the initial pattern from the substrate while leaving the spacer material in a spacer pattern; filling the spacer pattern with final material; and trimming the tilled pattern to remove portions of the final material beyond dimensions of the layout elements.
摘要:
The manufacturing of integrated circuits relies on the use of lithography simulation to predict the image of the mask created on the wafer. Such predictions can be used for example to assess the quality of the images, verify the manufacturability of such images, perform using OPC necessary correction of the mask data to achieve images close to the targets, optimize the printing parameters such as the illumination source, or globally optimize the source and the mask to achieve better printability. This disclosure provides a technique based on the association of at least one kernel function per source region or source point. Each kernel function can be directly convoluted with a mask image to create a prediction of the wafer image. As the kernel functions are associated with the source, the source can be easily changed to create new models. The optical system can be fully described by computing the possible kernels for all possible source points and all possible numerical apertures. Therefore this technique is ideally suited for source-mask optimization as well as source-mask-numerical aperture optimization, and their associated applications.
摘要:
The manufacturing of integrated circuits relies on the use of optical proximity correction (OPC) to correct the printing of the features on the wafer. The data is subsequently fractured to accommodate the format of existing mask writer. The complexity of the correction after OPC can create some issues for vector-scan e-beam mask writing tools as very small slivers are created when the data is converted to the mask write tool format. Moreover the number of shapes created after fracturing is quite large and are not related to some important characteristics of the layout like for example critical areas. A new technique is proposed where the order of the OPC and fracturing steps is reversed. The fracturing step is done first in order to guarantee that no slivers are created and that the number of shapes is minimized. The shapes created can also follow the edges of critical zones so that critical and non-critical edges can be differentiated during the subsequent OPC step.
摘要:
A method extends the use of phase shift techniques to complex layouts, and includes identifying a pattern, and automatically mapping the phase shifting regions for implementation of such features. The pattern includes small features having a dimension smaller than a first particular feature size, and at least one relatively large feature, the at least one relatively large feature and another feature in the pattern having respective sides separated by a narrow space. Phase shift regions are laid out including a first set of phase shift regions to define said small features, and a second set of phase shift regions to assist definition of said side of said relatively large feature. An opaque feature is used to define the relatively large feature, and a phase shift region in the second set is a sub-resolution window inside the perimeter of the opaque feature.
摘要:
A full phase shifting mask (FPSM) can be advantageously used in a damascene process for hard-to-etch metal layers. Because the FPSM can be used with a positive photoresist, features on an original layout can be replaced with shifters on a FPSM layout. Adjacent shifters should be of opposite phase, e.g. 0 and 180 degrees. In one embodiment, a dark field trim mask can be used with the FPSM. The trim mask can include cuts that correspond to cuts on the FPSM. Cuts on the FPSM can be made to resolve phase conflicts between proximate shifters. In one case, exposing two proximate shifters on the FPSM and a corresponding cut on the trim mask can form a feature in the metal layer. The FPSM and/or the trim mask can include proximity corrections to further improve printing resolution.
摘要:
Proximity effect correction has become a necessary step in the fabrication of integrated circuit in order to improve the pattern fidelity of current lithography processes. Current methodology is limited by data volume increase and correction inaccuracy due to extrapolation of the correction. The invention describes a methodology based on the interpolation of the correction between selected evaluation points of the target layout. By connecting the correction points this technique also provides a mean of reducing data volume and simplifying the mask writing, inspection and repair processes. The same methodology can be applied to layouts with non-printing assist features, where the correction of the assist features is based on the quality of the image of the main feature. For vector-scan mask write tool the segments interpolating the corrections can be fractured in segments with suitable angles.
摘要:
A method for defining a full phase layout for defining a layer of material in an integrated circuit is described. The method can be used to define, arrange, and refine phase shifters to substantially define the layer using phase shifting. Through the process, computer readable definitions of an alternating aperture, dark field phase shift mask and of a complimentary mask are generated. Masks can be made from the definitions and then used to fabricate a layer of material in an integrated circuit. The separations between phase shifters, or cuts, are designed for easy mask manufacturability while also maximizing the amount of each feature defined by the phase shifting mask. Cost functions are used to describe the relative quality of phase assignments and to select higher quality phase assignments and reduce phase conflicts.