Methodology for rapid and accurate simulation of alternating PSM SFR Workshop May 24, 2001 Kostas Adam, Andrew Neureuther Berkeley, CA 2001 GOAL: to demonstrate accuracy and generality of simulation method for application to other mask technologies by 9/30/2001. 5/24/2001

Motivation Discrepancy in the aerial image prediction of PSMs between scalar and vector based simulation methods. Rigorous methods based on the vector theory of light are not capable of large area mask simulations. Optical proximity correction (OPC) on PSM based on the scalar theory is not accurate. Subtle electromagnetic effects (e.g. cross-talk) in PSM are not well understood. 5/24/2001

0th order domain decomposition Alt. PSM e, E, H e1, E1, H1 = 180deg x z y e2, E2, H2 + - e3, E3, H3 Rel. error: 5/24/2001

Systematic manipulation of the Fourier spectrum (1) 180deg well T0 ,f0 and Lx0 are varied until the spectra are sufficiently matched T0 ,f0 600nm (4X) complex transmission Lx0 Tb ,fb position Lx0 is the main parameter that allows us to shape the spectrum: k+1 k0 k+3 k-3 k-1 k+/-2 5/24/2001

Systematic manipulation of the Fourier spectrum (2) T0 raises the overall level of the spectrum: f0 rotates the orders on the complex plane (in the same direction): 5/24/2001

1st order domain decomposition (modeling the cross-talk) Alt. PSM well 2 well 1 180deg = + - + CT(well1=>well2) + CT(well2=>well1) Rel. error: 5/24/2001

Decomposition error 2 180deg 0.05 0.6 0.6 Exact solution for 180o/360o APSM 180deg Error of the decompositions: 0.05 0.6 0.6 DEa0 for 180o/360o APSM DEa1 for 180o/360o APSM DEa1 for 180o/360o APSM 5/24/2001

Large 3D example: 0o/180o L/S alt. PSM 4 2 mm (1X) Ey (TE) 5.6mm (4X) 0o 180o mm (1X) Ex (TM) x y 1.6mm (4X) CD=100nm(1X) A total of 8 (1-4, TE and TM) 2D REMS are needed (~12min) Each of the two full 3D REMS requires 43hrs (550Mhz) and 1.57Gb Accuracy better than 99% is achieved with 430X computational speed-up 5/24/2001

Summary Demonstrated a way to improve the accuracy of modeling with scalar theory (better than 99% agreement with the vector theory can be achieved) Model based CAD tools that so far rely on scalar theory can be tuned to be very accurate (accurate 3D simulation becomes feasible for large – even full mask – areas) Demonstrated ways to decompose an alt. PSM by properly modeling the cross-talk between phase wells 5/24/2001