EUVL practical mask structure with light shield area for 32nm half pitch and beyond

Kamo, Takashi; Aoyama, Hajime; Tanaka, Toshihiko; Suga, Osamu; Abe, Tsukasa; Takikawa, Tadahiko; Hayashi, Naoya; Shoki, Tsutomu; Usui, Youichi; Hosoya, Morio

doi:10.1117/12.801576

Cited by 10 publications

(4 citation statements)

References 8 publications

(7 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To prevent a CDU impact from field-to-field flare, the mask black border should have very low EUV reflectivity (< 0.2%), which can only be achieved by absorber stack optimization (for example, using a very thick absorber), a special coating, double absorber technique or etching away the entire ML in the black border area [10], [11] . However, the CD impact can also be minimized by means of OPC, using information about exposure tool geometry and layout and also knowledge of absorber stack reflectivity.…”

Section: Image Border Field To Field Reflectionsmentioning

confidence: 99%

Mask aspects of EUVL imaging at 27nm node and below

Davydova

Setten

Han³

et al. 2011

SPIE Proceedings

View full text Add to dashboard Cite

EUVL requires the use of reflective optics including a reflective mask. The mask consists of an absorber layer pattern on top of a reflecting multilayer, tuned for 13.53 nm. The EUVL mask is a complex optical element with many parameters contributing the final wafer image quality. Specifically, the oblique incidence of light, in combination with the small ratio of wavelength to mask topography, causes a number of effects which are unique to EUV, such as an HV CD offset. These so-called shadowing effects can be corrected by means of OPC, but also need to be considered in the mask stack design. In this paper we will present an overview of the mask contributors to imaging performance at the 27 nm node and below, such as CD uniformity, multilayer and absorber stack composition, thickness and reflectivity. We will consider basic OPC and resulting MEEF and contrast. These parameters will be reviewed in the context of real-life scanner parameters both for the NXE:3100 and NXE:3300 system configurations. The predictions will be compared to exposure results on NXE:3100 tools, with NA=0.25 for different masks. Using this comparison we will extrapolate the predictions to NXE:3300, with NA=0.33. Based on the lithographic investigation, expected requirements for EUV mask parameters will be proposed for 22 nm node EUV lithography, to provide guidance for mask manufacturers to support the introduction of EUV High Volume Manufacturing.

show abstract

Section: Image Border Field To Field Reflectionsmentioning

confidence: 99%

Mask aspects of EUVL imaging at 27nm node and below

Davydova

Setten

Han³

et al. 2011

SPIE Proceedings

View full text Add to dashboard Cite

show abstract

“…In our previous papers we had demonstrated that by the thinning down of LR-TaBN absorbers with EUV light shield area, the shadowing effect could be reduced without any loss of printability. 1,2,3 In essence, one of the key issues with EUVL is to make defect-free masks. There are mainly three categories of mask defects: phase defects that are embedded within the multilayer blanks, hard defects that are formed during the patterning of absorber, and soft defects that can result from mask handling.…”

Section: Introductionmentioning

confidence: 99%

Defect printability of thin absorber mask in EUV lithography

Kamo¹,

Aoyama²,

Arisawa³

et al. 2009

Alternative Lithographic Technologies

Self Cite

View full text Add to dashboard Cite

The effect of mask absorber thickness on defect printability in EUV lithography was studied. In case of very thin absorber, when used for EUVL mask, it became necessary to set specifications for mask defects for the manufacturability of ULSI devices because mask absorber thickness could impact defect printability. We prepared programmed mask defects of LR-TaBN absorber with various thicknesses. We then investigated defect printability of thin absorber mask with Small Field Exposure Tool (SFET) by comparing the data with simulation results.

show abstract

“…So it is necessary to correct the pattern size at the process of OPC or dose correction at the electron beam writing. To avoid this complexity, low reflective frame surrounding the exposure field has been developed [1]. As the reflectivity of EUV light at the LTEM substrate surface is sufficiently low, etching multilayer as a frame is one of the advantageous ways because it can be made by simple lithography process without any deterioration of CD quality [2].…”

Section: Introductionmentioning

confidence: 99%

Simulation of image placement error due to fabrication of black border on EUV mask

2014

View full text Add to dashboard Cite

To satisfy the requirement on the image placement accuracy, it is very important to consider the stress of the films on the mask substrate. The stress of the EUV mask is much larger than several kinds of optical masks because reflective Mo/Si multilayer (ML) has large compressive stress. In recent years, thinner absorber has been proposed because of better resolution and less shadowing effect. However it results in the leakage of the light to the adjacent chips on wafer. Then the light shield around the pattern area on the mask has been developed. From the viewpoint of manufacturability, etched multilayer black border (BB) is advantageous. Pattern displacement occurs at the edge of the multilayer etched BB. Measured pattern displacement error increased near the BB and it was simulated by using finite element method. The displacement depends strongly on the ML stress and it is successfully described by the release of the compressive stress at the edge of the black border. Most of the deformation near the BB remains even if the mask is chucked to the flat surface. Simulation using various models are discussed and compared with experimental results.

show abstract

EUVL practical mask structure with light shield area for 32nm half pitch and beyond

Cited by 10 publications

References 8 publications

Mask aspects of EUVL imaging at 27nm node and below

Mask aspects of EUVL imaging at 27nm node and below

Defect printability of thin absorber mask in EUV lithography

Simulation of image placement error due to fabrication of black border on EUV mask

Contact Info

Product

Resources

About