Abstract:
By directly using relative biases, contained in the relative bias date matrix, and by appropriately weighting the components thereof, sampling rate limitations in an APC control scheme may be efficiently compensated for. In particular embodiments, an age-based weighting factor is established that scales measurement data uncertainty according to the delay with which the corresponding measurement data for a specific control thread are obtained.
Abstract:
A method includes providing a plurality of sampling rules. Each sampling rule is associated with at least one of a plurality of sites on a workpiece. At least one penalty is assigned to each sampling rule. The penalty is assessed responsive to a previous site selection not satisfying the associated sampling rule. A subset of the sites is selected for subsequent metrology based on the sampling rules and the assessed penalties. At least one characteristic of the workpiece is measured at the selected subset of the sites.
Abstract:
The present invention is directed to several inventive methods of monitoring anneal processes performed on implant regions, and a system for accomplishing same. In one aspect, the method comprises forming a first plurality of implant regions in a semiconducting substrate, performing at least one anneal process on implant regions, performing a scatterometric measurement of at least one of the implant regions after at least a portion of the anneal process is performed to determine a profile of the implant region and determining an effectiveness of the anneal process based upon the determined profile of the implant region. In other embodiments, one or more parameters of the anneal process may be varied on subsequently processed substrates based upon the determined efficiency of the anneal process.
Abstract:
A method of using scatterometry measurements to determine and control conductive interconnect profiles is disclosed. In one embodiment, the method comprises providing a library of optical characteristic traces, each of which correspond to a grating structure comprised of a plurality of conductive interconnects having a known profile, providing a substrate having at least one grating structure formed thereabove, the formed grating structure comprised of a plurality of conductive interconnects having an unknown profile, and illuminating the formed grating structure. The method further comprises measuring light reflected off of the grating structure to generate an optical characteristic trace for the formed grating structure and determining a profile of the gate electrode structures comprising the formed grating structure by correlating the generated optical characteristic trace to an optical characteristic trace from the library. In another embodiment, the method disclosed herein comprises comparing a generated optical characteristic trace of conductive interconnects having an unknown profile to a target trace established for conductive interconnects having an ideal or acceptable profile.
Abstract:
A method includes acquiring metrology data associated with a process. Bias information associated with the process is determined. The metrology data is adjusted based on the bias information to generate bias-adjusted metrology data. The bias-adjusted metrology data is filtered to identify and reject outlier data. The process is controlled based on the metrology data remaining after the rejection of the outlier data.
Abstract:
The present invention is generally directed to various structures for analyzing electromigration, and methods of using same. In one illustrative embodiment, the method includes forming a grating structure above a semiconducting substrate, the grating structure being comprised of a plurality of conductive features, forcing an electrical current through at least one of the conductive features until a resistance of the conductive feature increases by a preselected amount, and performing at least one scatterometric measurement of the conductive feature to determine a critical dimension of the conductive feature. In another illustrative embodiment, the method includes forming a plurality of grating structures above a semiconducting substrate, each of the grating structures being comprised of a plurality of conductive features having the same critical dimension, the critical dimension of the features of each of the plurality of grating structures being different, and forcing an electrical current through at least one of the conductive features in each of the plurality of grating structures until a resistance of the conductive feature increases by a preselected amount.
Abstract:
The present invention is generally directed to various methods of detecting degradation in photolithography processes based upon scatterometric measurements of grating structures, and a device comprising such structures. In one embodiment, the method comprises providing a wafer comprised of a plurality of grating structures, each of the grating structures being comprised of a plurality of features, each of the grating structures having a different critical dimension, illuminating at least one of the grating structures, measuring light reflected off of at least one of the grating structures to generate an optical characteristic trace for the grating structure, and determining the presence of residual photoresist material between the features of the grating structure by comparing the generated optical characteristic trace to at least one optical characteristic trace from a library. In some embodiments, the grating structures are arranged in a linear array. In one illustrative embodiment, the device comprises a wafer and a plurality of grating structures formed above the wafer, each of the grating structures having a different critical dimension, and at least one of the grating structures having a critical dimension that is less than an anticipated range of critical dimensions for integrated circuit devices to be formed on a wafer.
Abstract:
The present invention is generally directed to various methods for calibrating optical-based metrology tools. In one illustrative embodiment, the method comprises performing a metrology process on a specimen using an optical-based metrology tool to obtain optical characteristic data and comparing the obtained optical characteristic data to target optical characteristic data established for the specimen.
Abstract:
The present invention is generally directed to a method of controlling photolithography processes based upon scatterometric measurements of sub-nominal grating structures, and a system for accomplishing same. In one embodiment, the method comprises providing a library of optical characteristic traces, each of which corresponds to a sub-nominal grating structure comprised of a plurality of photoresist features having a known degree of residual photoresist material positioned between the photoresist features, forming a process layer above a semiconducting substrate, and forming a layer of photoresist above the process layer. The method further comprises forming at least one sub-nominal grating structure in the layer of photoresist, the sub-nominal grating structure being comprised of a plurality of photoresist features, illuminating the formed sub-nominal grating structure, measuring light reflected off of the formed sub-nominal grating structure to generate an optical characteristic trace for the formed sub-nominal grating structure, and determining the presence of residual photoresist material between the features of the formed sub-nominal grating structure by comparing the generated optical characteristic trace to at least one optical characteristic trace from the library.
Abstract:
A method of using scatterometric techniques to control stepper process is disclosed. In one illustrative embodiment, the method comprises providing a library of optical characteristic traces, each of which corresponds to a grating structure comprised of a plurality of photoresist features having a known profile, and forming at least one grating structure in a layer of photoresist, wherein the formed grating structure is comprised of a plurality of photoresist features having an unknown profile. The method further comprises illuminating the formed grating structure, measuring light reflected off of the formed grating structure to generate an optical characteristic trace for the formed grating structure, comparing the generated optical characteristic trace to at least one optical characteristic trace from the library, and modifying at least one parameter of a stepper exposure process to be performed on at least one subsequently processed wafer based upon the comparison of the generated optical characteristic trace and the optical characteristic trace from the library. In another embodiment, the generated optical characteristic trace for the grating structure is compared to a target optical characteristic trace for the grating structure, and at least one parameter of an exposure process to be performed on a layer of photoresist formed on a subsequently processed wafer may be determined or modified based upon this comparison.