Actual performance data analysis of overlay, focus, and dose control of an immersion scanner for double patterning

Currently, it is considered that one of the most favorable options for the 32 nm HP node is pitch-splitting double patterning, which requires the lithography tool to achieve high productivity and high overlay accuracy simultaneously. In the previous work [1] , we described the concepts and the technical features of Nikon's immersion scanner based on our newly developed platform, Streamlign, designed for 2nm overlay, 200wph throughput, and short setup time. In this paper, we present the latest actual performance of S620D with the Streamlign platform.Owing to the high repeatability of our new encoder metrology system, Bird's Eye Control, and Stream Alignment, S620D achieves less than 2 nm overlay accuracy, less than 15nm focus accuracy, and successful 32 and 22 nm L/S pitchsplitting double patterning exposures. Furthermore, the results at high scanning speed up to 700 mm/s are fine and we have successfully demonstrated over 4,000 wpd throughput, which confirms the potential for high productivity. Nikon has developed this Streamlign as an optimized long life platform based on the upgradable Modular 2 structure for upcoming generations. The performance of S620D indicates the possibility of immersion extension down through the 22 nm HP node and beyond.

show abstract

“…A more detailed data analysis of overlay, focus, and dose control in S620D is presented in another paper [7] . …”

Section: Cdu : Line 25 Space 33 (3σ [Nm])mentioning

confidence: 99%

Latest performance of immersion scanner S620D with the Streamlign platform for the double patterning generation

et al. 2010

Self Cite

View full text Add to dashboard Cite

show abstract

“…By incorporating sophisticated encoders, scanner overlay performance has been dramatically improved to less than 2 nm, and within wafer focus uniformity below 20 nm has been demonstrated via the phase shift focus monitor (PSFM) test method [4] . The NSR-S620D has already been implemented in the production of NAND flash and MPU, and in this paper we will provide an update on the latest performance of the tool, with an emphasis on overlay and focus control.…”

Section: Introductionmentioning

confidence: 99%

Stability and calibration of overlay and focus control for a double patterning immersion scanner

et al. 2011

Self Cite

View full text Add to dashboard Cite

To achieve the 2 nm overlay accuracy required for double patterning, we have introduced the NSR-S620D immersion scanner that employs an encoder metrology system. The key challenges for an encoder metrology system include its stability as well as the methods of calibration. The S620D has a hybrid metrology system consisting of encoders and interferometers, in XY and Z. The advantage of a hybrid metrology system is that we can continuously monitor the position of the stage using both encoders and interferometers for optimal positioning control, without any additional metrology requirements or throughput loss. To support this technology, the S620D has various encoder calibration functions that make and maintain the ideal grid, and control focus. In this paper we will introduce some of the encoder calibration functions based on the interferometer. We also provide the latest performance of the tool, with an emphasis on overlay and focus control, validating that the NSR-S620D delivers the necessary levels of accuracy and stability for the production phase of double patterning.

show abstract

“…To respond to this shrinkage requirement, semiconductor exposure tools, such as steppers and scanners that have a high numerical aperture (NA) and projection optics for a shorter exposure wavelength, have continuously been developed. [1][2][3] Since NA is high, the depth of focus (DOF) on a wafer is several hundred nanometer or less under the present condition, therefore several ten nanometer focus control, approximately 10% of DOF, is required in lithography. However, the accuracy of the focus measurement of the actual process wafer does not meet current requirement value.…”

Section: Introductionmentioning

confidence: 99%

“…(b) Flow chart of our proposing signal processing as follows. (1) Basis functions are determined by using KL expansion (2). We calculate coefficients of basis function by using inner product between the input signal and the basis function.…”

mentioning

confidence: 99%

Signal Processing Using Karhunen–Loève Expansion for Wafer Focus Measurement in Lithography

Oishi

Ina

Miyashita

2011

Jpn. J. Appl. Phys.

View full text Add to dashboard Cite

We propose a new signal processing method using Karhunen–Loève (KL) expansion for wafer focus measurement in lithography. With the improvement in the critical dimension (CD) accuracy, more high accuracy of wafer focus measurement becomes to be necessary. Recently, it is said that focus accuracy should be required within several ten nanometers. The accuracy of the focus measurement of the actual process wafer does not meet the requirement values due to the complexity of its structure. The objective of this study is the improvement of the focus accuracy for the actual process wafers. Our proposing focus signal processing has two steps. The first step is a supervised learning step in which main component signal waveforms (basis functions) are obtained by using KL expansion from many focus signals whose center positions are known in advance. The second step is a center position detecting step in which an input signal is approximated by using the basis functions obtained in the learning step and the center position of the signal is detected. From a comparison between the conventional signal processing and the proposing signal processing, we obtained the following result to simulated signal. Focus accuracy was rapidly improved (97%) when three basis functions were used for the approximation. By using this technology, the focus detection system can be achieved with a high accuracy and robust against various process wafers.

show abstract

Actual performance data analysis of overlay, focus, and dose control of an immersion scanner for double patterning

Cited by 4 publications

References 0 publications

Latest performance of immersion scanner S620D with the Streamlign platform for the double patterning generation

Latest performance of immersion scanner S620D with the Streamlign platform for the double patterning generation

Stability and calibration of overlay and focus control for a double patterning immersion scanner

Signal Processing Using Karhunen–Loève Expansion for Wafer Focus Measurement in Lithography

Contact Info

Product

Resources

About