Correlating scatterometry to CD-SEM and electrical gate measurements at the 90-nm node using TMU analysis

Sendelbach, Matthew; Archie, Charles N.; Banke, Bill; Mayer, Jason; Nii, H.; Herrera, Pedro; Hankinson, Matt

doi:10.1117/12.538009

Cited by 22 publications

(13 citation statements)

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“…al. 9 and involves the use of TMU error bars. This technique estimates the uncertainty with which a TMU result is calculated by providing an upper and lower estimate for TMU.…”

Section: Display Of Tmu Resultsmentioning

confidence: 99%

Feedforward of mask open measurements on an integrated scatterometer to improve gate linewidth control

Sendelbach¹,

Natzle²,

Archie³

et al. 2004

Metrology, Inspection, and Process Control for Microlithography XVIII

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As feature geometries decrease, the budgeted error for process variations decreases as well. Keeping these variations within budget is especially important in the area of gate linewidth control. Because of this, wafer-to-wafer control of gate linewidth becomes increasingly necessary. This paper shows results from 300 mm wafers with 90 nm technology that were trimmed during the gate formation process on an etch platform. After the process that opened the gate hard mask and stripped the resist, the wafers were measured using both an integrated scatterometer and a stand-alone CD-SEM. The measurements were then used to determine the appropriate amount to be trimmed by the Chemical Oxide Removal (COR) chamber that is also integrated onto the etch system. After the wafers were trimmed and etched, they were again measured on the integrated scatterometer and stand-alone CD-SEM. With the CD-SEM as the Reference Measurement System (RMS), Total Measurement Uncertainty (TMU) analysis was used to optimize the Optical Digital Profilometry (ODP) model, thus facilitating a significant reduction in gate linewidth variation. Because the measurement uncertainty of the scatterometer was reduced to a level approaching or below that of the RMS, an improvement to TMU analysis was developed. This improvement quantifies methods for determining the measurement uncertainty of the RMS under a variety of situations.

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“…al. 9 and involves the use of TMU error bars. This technique estimates the uncertainty with which a TMU result is calculated by providing an upper and lower estimate for TMU.…”

Section: Display Of Tmu Resultsmentioning

confidence: 99%

Feedforward of mask open measurements on an integrated scatterometer to improve gate linewidth control

Sendelbach¹,

Natzle²,

Archie³

et al. 2004

Metrology, Inspection, and Process Control for Microlithography XVIII

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“…Establishing accuracy for metrology is costly but necessary for the success and competitiveness of semiconductor technology [10], [11]. A few other cases demonstrate the importance of accurate metrology in process development.…”

Section: F Importance Of Accuracymentioning

confidence: 97%

“…Precision is a long-term reproducibility from a single tool that can be thought to be the random component of that tool's uncertainty. Inaccuracy (or accuracy) is any systematic component to this single tool's uncertainty, thought of in terms of slope, offset, and "total measurement uncertainty" (TMU), which is the average size of residuals from correlating the tool's response against the response from a reference measurement system [5], [10], [11]. Matching is the precision and accuracy-type (both random and systematic) errors extended to multiple tools.…”

Section: A Elements Of Uncertaintymentioning

confidence: 99%

Value-Added Metrology

Bunday¹,

Allgair²,

Caldwell³

et al. 2007

IEEE Trans. Semicond. Manufact.

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The conventional premise, long-touted among the semiconductor processing community, that metrology is a "non-value-added necessary evil," is a misleading and dangerous assertion, which must be viewed as obsolete thinking. Many metrology applications are key enablers to traditionally labeled "value-added" processing steps in lithography and etch, such that they can be considered integral parts of the processes.Various key trends in modern, state-of-the-art processing such as optical proximity correction, design for manufacturability, and advanced process control are based, at their hearts, on the assumption of fine-tuned metrology, in terms of uncertainty and accuracy. These trends are vehicles where metrology thus has large opportunities to create value through the engineering of tight and targetable process distributions. Such distributions make possible predictability in speed-sorts and in other parameters, which results in a high-end product. Additionally, significant reliance has also been placed on defect metrology to predict, improve, and reduce yield variability. The necessary quality metrology is strongly influenced by not only the choice of equipment, but also the quality application of these tools in a production environment. The ultimate value added by metrology is a result of quality tools run by a quality metrology team using quality practices. This paper will explore the relationships among present and future trends and challenges in metrology, including equipment, key applications, and metrology deployment in the manufacturing flow. Of key importance are metrology personnel, with their expertise, practices, and metrics in achieving and maintaining the required level of metrology performance, including where precision, matching, and accuracy fit into these considerations. The value of metrology will be demonstrated to have shifted to being a "key enabler of large revenues," debunking the out-of-date premise that metrology is "non-value-added." Index Terms-Advanced process control (APC), critical dimension (CD), design-based metrology (DBM), design for manufacturability (DFM), ISMI, metrology, optical proximity correction (OPC).

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“…Critical parameters are defined as those parameters that need to be measured to control the device performance (e.g. the critical dimension (CD) of the poly-silicon gate, which directly impacts device speed) [1]. Required parameters are those parameters that when changed, due to process variation, significantly impact the spectra and thus the accuracy of the measurement.…”

Section: Introductionmentioning

confidence: 99%

Improved scatterometry time to solution for leading-edge logic applications

Vaid

Sendelbach

Komarov³

et al. 2010

2010 IEEE/SEMI Advanced Semiconductor Manufacturing Conference (ASMC)

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This paper describes an innovative approach to scatterometry modeling, significantly reducing time to solution compared to the industry's current best practices. One of the drawbacks to traditional scatterometry measurement techniques is the time required to optimize the model, which includes material optical constant extraction, model build time, initial model optimization, and model testing. A novel methodology that includes both stability and self-consistent scatterometry accuracy prediction can achieve an order of magnitude gain in productivity over prior methods. This technique creates opportunities among semiconductor chip manufacturers for wider scatterometry adoption at advanced technology nodes, where scatterometry is often the only reliable non-destructive metrology for device structure dimensions. The reductions in cycle time and improvements in accuracy prediction are keys to the success of scatterometry as an enabler for advanced process control and monitoring. This paper presents results on a conventional poly gate litho and final inspection and on leading-edge high-k metal gate after-etch applications. Spectroscopic ellipsometry is used to collect spectra from the gratings on the wafers. Then scatterometry results are obtained using the new approach and via traditional industryaccepted procedures to compare time to solution. To confirm the validity of the results, reference metrology data are collected on a CDSEM and TEM and the total measurement uncertainty is evaluated.

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Correlating scatterometry to CD-SEM and electrical gate measurements at the 90-nm node using TMU analysis

Cited by 22 publications

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Feedforward of mask open measurements on an integrated scatterometer to improve gate linewidth control

Feedforward of mask open measurements on an integrated scatterometer to improve gate linewidth control

Value-Added Metrology

Improved scatterometry time to solution for leading-edge logic applications

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