<title>Manufacturing considerations for implementation of scatterometry for process monitoring</title>

Abstract

The continuing demand for higher frequency microprocessors and larger memory arrays has led to decreasing device dimensions and smaller process control windows. Decreasing process control windows have created a need for higher precision metrology to maintain an acceptable precision to tolerance ratio with a reasonable sampling rate. In order to determine and reduce across chip, across wafer, and across lot linewidth variations, higher sampling is required which, in turn, demands faster move acquire measure (MAM) times to maintain throughput. Finally, the need to detect and quantify sidewall angle changes in addition to CD measurements is becoming critical. Spectroscopic Scatterometry is a metrology technique which offers the potential to meet these requirements. This work explores some of the fundamental technology concerns for implementing scatterometry in a manufacturing environment. These concerns include mark requirements and characterization necessary for library generation. Comparison of scatterometry data to in-line CD SEM, x-sectic'n SEM, and AFM results will be presented.

Resonant and scatterometric grating-based nanophotonic structures for biosensing

“…Originally, scatterometry involved measuring all of the diffracted orders as a function of the scattering angle in what is known as the θ − 2 configuration [18,19]. Later, this approach was simplified by measuring only the zeroth-order diffraction which with the shrinkage of the pattern period it becomes the main dominant diffraction at visible and near infrared wavelengths [22,23]. To improve the speed, sensitivity and avoid angular scanning, the spectroscopic approach has then emerged in an analogous manner to spectroscopic ellipsometry (SE) which involves measuring the reflected spectrum or its ellipsometric parameters at fixed incidence angle.…”

“…This happens at a specific wavelength and incidence angle of the incident beam [14] at which the resonance condition is satisfied, whereby the re-diffracted beam destructively interferes with the transmitted beam, so that the incident light beam is completely reflected [15,16]. Scattering from non-resonant grating structures have also been shown to be highly sensitive to the grating parameters and to the layers surrounding the grating structure [17][18][19][20][21][22][23][24]. This property is being used to optically monitor layers thickness, critical dimension and overlay mis-registration, which are crucial parameters to control the fabrication process in the nanoelectronic industry.…”

Characterization and Control of Etch Processes Using Multiple Metrologies

“…Scatterometry is an attractive inline metrology approach due to the measurement speed and precision [12,13].…”

Effective medium approximation of anisotropic lamellar nanogratings based on Fourier factorization

“…At this point, it is possible to express elements of permittivity tensor ε i j in the form of Fourier series and after that to use the Toeplitz matrices representing each element in (1). But this traditional approach is not correct and for truncated series leads to numerical errors in any used numeric implementation.…”

“…There is a need for adaptation of the optical methods for characterization and control of lithographic and nanostructurization processes and determination of optical functions of nanosize objects (for instance quantum wires and dots). Straightforward method of increasing sensitivity to subwavelength and nanosize objects is to produce a periodic system from such objects, usually lamellar gratings [1,2].…”