PSM polarimetry: monitoring polarization at 193nm high-NA and immersion with phase shifting masks

McIntyre, Gregory; Neureuther, Andrew R.

doi:10.1117/12.599058

Cited by 11 publications

(12 citation statements)

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“…In 2005 the first polarization monitor mask for photolithography was proposed by G. McIntyre and A. Neureuther. [2][3][4] A radial phase grating on a mask forms a twin-peak image distorted according to the direction and the purity of the linear polarization on the wafer. Thus, the degree of the distortion is utilized as an indicator of a degree of polarization.…”

Section: Introductionmentioning

confidence: 99%

Polarimetry of illumination for 193-nm lithography used for the manufacture of high-end LSIs

Nomura

Furutono

2007

SPIE Proceedings

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We have constructed a theory of polarimetry of illumination used in 193-nm lithography equipments, fabricated a polarimeter mask, and demonstrated it for a hyper-NA (numerical aperture) lithography scanner. The polarimeter mask comprises newly-developed polarizers and quarter-wave (λ/4) plates. The thin plate polarizers are made of calcite (CaCO 3 ), and the λ/4 plates are composed of two crystalline quartz (α-SiO 2 ) plates and two sapphire (Al 2 O 3 ) plates. A light traveling through a window of the polarimeter mask reaches an image detector at the wafer level through projection optics. Whereas the polarization states of the projection optics are unknown to us, Stokes parameters of the illumination light are formulated without any influence from the projection optics.

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Section: Introductionmentioning

confidence: 99%

Polarimetry of illumination for 193-nm lithography used for the manufacture of high-end LSIs

Nomura

Furutono

2007

SPIE Proceedings

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“…Reference [3] reports the procedure for calculating the polarimetric measurement matrix (W) when the analyzers can be calibrated with perfect polarization states. However, in the likely event that the light used to calibrate the analyzers is not perfect (but measured via an independent means such as Apollo), the W matrix is calculated as follows:…”

Section: Test Reticle 1: Radial Phase Grating Polarization Analyzersmentioning

confidence: 99%

“…An additional improvement is provided by maximizing proximity effects in the form of the proximity effect polarization analyzers 3 (PEPA), shown in Figure 1c. Derived mathematically in reference [3], the PEPA maximizes the coherent spill-over of electric fields oriented normal to the wafer surface, thus maximizing the polarization-dependent high-NA signal. For both embodiments, imaging two orthogonal analyzers provides a means to monitor the balance between orthogonal linear polarization states.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, the development of an independent means to verify and monitor tool polarization becomes critical to ensure the maximum benefit from polarized illumination is obtained. This paper reports on the initial experimental verification of an in-situ polarization monitoring technique that was introduced conceptually in references [3] and [4]. By taking advantage of high-NA vector effects, a series of phase shifting test mask patterns serve as analyzers to produce polarization-dependent signals at the wafer plane.…”

Section: Introductionmentioning

confidence: 99%

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Experimental verification of PSM polarimetry: monitoring polarization at 193nm high-NA with phase shift masks

et al. 2006

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The initial experimental verification of a polarization monitoring technique is presented. A series of phase shifting mask patterns produce polarization dependent signals in photoresist and are capable of monitoring the Stokes parameters of any arbitrary illumination scheme. Experiments on two test reticles have been conducted. The first reticle consisted of a series of radial phase gratings (RPG) and employed special apertures to select particular illumination angles. Measurement sensitivities of about 0.3 percent of the clear field per percent change in polarization state were observed. The second test reticle employed the more sensitive proximity effect polarization analyzers (PEPA), a more robust experimental setup, and a backside pinhole layer for illumination angle selection and to enable characterization of the full illuminator. Despite an initial complication with the backside pinhole alignment, the results correlate with theory. Theory suggests that, once the pinhole alignment is corrected in the near future, the second reticle should achieve a measurement sensitivity of about 1 percent of the clear field per percent change in polarization state. This corresponds to a measurement of the Stokes parameters after test mask calibration, to within about 0.02 to 0.03. Various potential improvements to the design, fabrication of the mask, and experimental setup are discussed. Additionally, to decrease measurement time, a design modification and double exposure technique is proposed to enable electrical detection of the measurement signal.

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“…In 2005, the first monitor technology of polarization was proposed by G. McIntyre and A. Neureuther. [4][5][6] However, the monitor does not realize high spatial resolution as it discloses the distributions of polarization properties in a source plane, nor does it distinguish the polarization properties of illumination from the measurement results. New polarimetry technologies were required.…”

Section: Introductionmentioning

confidence: 98%

In-situ polarimetry of illumination for 193-nm lithography

Nomura

Furutono

2008

Optical Microlithography XXI

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Ellipsometry is defined as a technique for determining the properties of a bulk material or a thin film, such as optical index and thickness, from the measurement of a polarization state of a reflected light or a change of polarization states between the incident and reflected lights. On the other hand, polarimetry is defined as a technique for determining a polarization state of a light. In other words, ellipsometry uses polarization as a probe and polarimetry measures polarization itself. We have constructed a theory of polarimetry of illumination used in lithography equipments, fabricated a polarimeter mask, and demonstrated it for a hyper-NA (numerical aperture) immersion lithography scanner. The polarimeter mask comprises polarizers and quarter-wave (λ/4) plates that are crammed into a narrow space with a height of 6.35 mm. The thin plate polarizers available at a wavelength of 193 nm are made of calcite, and the λ/4-plates insensitive to angle of incidence are made of four thin plates, two of which are crystalline quartz; the other two are sapphire. A light traveling through a window of the polarimeter mask reaches an image detector at the wafer level through projection optics. Stokes parameters of the illumination light can be measured without any influence from polarization characteristics of the projection optics between the mask and the image detector.

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PSM polarimetry: monitoring polarization at 193nm high-NA and immersion with phase shifting masks

Cited by 11 publications

References 0 publications

Polarimetry of illumination for 193-nm lithography used for the manufacture of high-end LSIs

Polarimetry of illumination for 193-nm lithography used for the manufacture of high-end LSIs

Experimental verification of PSM polarimetry: monitoring polarization at 193nm high-NA with phase shift masks

In-situ polarimetry of illumination for 193-nm lithography

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