Investigation of overlay errors due to the interaction of optical and extreme ultraviolet mask fabrication processes
Pattern layout utilized in the FE models. There are cells in the pattern area with each unit cell having dimensions of . Dimensions in millimeters except as specified.
Unit cells of: (a) pattern I for the active-area layer; (b) pattern II for the poly layer; (c) pattern III for the contact layer; (d) pattern IV for the metal layer; and (e) final pattern with all four layers.
(a) EUV mask process steps and (b) EUV chucking fabrication configuration utilized in the FE simulations (exposure chucking is illustrated).
(a) Optical mask process steps simulated with the FE models; (b) three-point mount for optical patterning/metrology, and (c) vacuum chuck for optical exposure. All dimensions in millimeters.
Schematic of the submodeling techniques.
IPD tracking for: (a) pattern II (poly layer, EUV processing) and (b) pattern IV (metal layer, optical processing). The maximum pattern transfer IPD is for the poly layer. For the metal layer, the maximum IPD is with a three-point mount in the -beam tool and with a flat chuck in the -beam tool. Magnification corrections have not been applied to these values.
Pattern transfer IPD in the unit cell at corner location for; (a) the poly layer and (b) the metal layer. The maximum IPD is for the poly layer and for the metal layer (with three-point mount in the -beam tool), after magnification corrections. (c) Overlay errors between these two layers with maximum value of in the unit cell at corner location. It should be noted that different scaling was used in these vector plots to illustrate the magnitudes.
Four layers included in the overlay investigation.
EUVL and optical mask fabrication parameters utilized in the FE simulations.
Pattern transfer IPD of each layer and overlay errors between the four layers.
Article metrics loading...
Full text loading...