&lt;title&gt;The Optical Stepper With A High Numerical Aperture I-Line Lens And A Field-By-Field Leveling System&lt;/title&gt;

Suwa, Kyoichi; Ushida, Kazuo

doi:10.1117/12.968424

Cited by 8 publications

(4 citation statements)

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“…To solve this problem, the practical focusing process could be conducted under a coarse-fine focusing strategy. In coarse focusing, a slot or hole like mark is projected onto the central position of an exposing field, and then reflected onto another side to transform the up and down height variation into image shift (this way is similar to reference [6]). The coarse focusing method generally achieves accuracy within 1 m. Hereafter, the rest fine focusing procedure is all about our moiré-based four-channel scheme.…”

Section: The Four-channel Focusing and Leveling Schemementioning

confidence: 99%

“…Taking into account the narrow space between projection objective and the wafer, the focusing process (generally, the focusing process is the core issue of the focusing and leveling processes) was always performed by constructing a triangular optical path to transform the up and down fluctuations of the horizontal wafer into the displacement of reflected light [6]- [13]. For the first time, a slot like mark based technique, that detects the shift of slot caused by vertical movement of the wafer, was proposed by Suwa [6]. Then, in [7]- [9], it is further demonstrated that the heights at multi-points can be obtained by utilizing the slot or pinhole array marks so that the focusing and leveling could be achieved simultaneously using those heights data.…”

Section: Introductionmentioning

confidence: 99%

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A Moiré-Based Four-Channel Focusing and Leveling Scheme for Projection Lithography

Yan

et al. 2014

IEEE Photonics J.

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Focusing and leveling are two imperative processes to adjust the wafer onto the ideal focal plane of projection lithography tools. Based on moiré fringes formed by particularly designed dual-grating marks, the four-channel focusing and leveling scheme is proposed and demonstrated. These relationships between the tilted amount of wafer, the vertical defocusing amount, and the phase distributions of moiré fringes are deduced. A single-channel experimental setup is constructed to verify the performances of proposed method. Results indicate that the tilted amount and the vertical defocusing amount can be precisely detected with accuracy at 10 À4 rad and several nanometers level, respectively, and therefore meet the demand of the high-demanding focusing and leveling processes.

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Section: The Four-channel Focusing and Leveling Schemementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Moiré-Based Four-Channel Focusing and Leveling Scheme for Projection Lithography

Yan

et al. 2014

IEEE Photonics J.

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“…The Nikon company's optical measurement system of stepper lithograph level sensors is shown in fig. 1 [5][6] . The beam of light which come from a light emitting diode (LED) focus on the diaphragm across focus lens, becomes a parallel beam of light by lens 1 and incidence aslant to a Si (silicon) wafer, again focus on the photo-electric detector (e.g.…”

Section: The Past Leveling Adjustment Technologymentioning

confidence: 99%

Development of a novel optical alignment system for accurate leveling adjustment of a high-precision chip mounter

Zhong

Yang

et al. 2006

SPIE Proceedings

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Automatic high-precision chip mounter have been applied frequently in high-precision and complex craft situations. The key to the equipment is the vision alignment system. The leveling adjustment is the important part and preconditin of the alignment .On the basis of a correlative leveling adjustment technlogy, a novel optical alignment system for leveling adjustment is presented. Its optical system is designed and its flow of image processing is discussed. To avoid the influence of interference, the polarization of the light is used skillfully in the optical system. The result of simulated experiments of the reticle-mark collected by a charge couple device (CCD) indicates that the system can meet the precision needs of an automatic chip mounter vision alignment system and it is reasonable.

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“…In semiconductor manufacturing, the exposure apparatus for microlithography, in which high-resolution projection optics are employed, has played an important role in shrinking the device geometry. Since Nikon's innovation in 1988 of field leveling technology 1,2) for the semiconductor exposure process, it has been necessary to perform focus and field curvature measurements in the intrafield at a number of measurement points. To measure the best focus position automatically using an optical sensor in a short time, the development of a new focus measurement methodology is essential.…”

Section: Introductionmentioning

confidence: 99%

Theoretical analysis of focus wedge mark for best-focus determination in photolithography

Suwa¹,

Yashiki²,

Hirukawa³

2014

Jpn. J. Appl. Phys.

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The focus wedge mark (FWM), a periodic array of wedge shaped marks, is a tool used to determine the best-focus position in photolithography. Here, we develop a one-dimensional physical model for the FWM and analyze the focus dependence of the wedge length under coherent imaging conditions. The amplification factor of the FWM, which describes the superiority of the FWM compared to measurements based on line and space marks, is determined by the geometrical magnification of the wedge. We show that around the exposure dose energy typically used in lithography the amplification factor is much higher than the geometrical magnification. Numerical lithography simulations confirm that the focus sensitivity of the FWM is much higher than that of a line and space pattern.

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<title>The Optical Stepper With A High Numerical Aperture I-Line Lens And A Field-By-Field Leveling System</title>

Cited by 8 publications

References 0 publications

A Moiré-Based Four-Channel Focusing and Leveling Scheme for Projection Lithography

A Moiré-Based Four-Channel Focusing and Leveling Scheme for Projection Lithography

Development of a novel optical alignment system for accurate leveling adjustment of a high-precision chip mounter

Theoretical analysis of focus wedge mark for best-focus determination in photolithography

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