Laser bandwidth effect on overlay budget and imaging for the 45 nm and 32nm technology nodes with immersion lithography

Abstract

The laser bandwidth and the wavelength stability are among the important factors contributing to the CD Uniformity budget for a 45 nm and 32nm technology node NV Memory. Longitudinal chromatic aberrations are also minimized by lens designers to reduce the contrast loss among different patterns. In this work, the residual effect of laser bandwidth and wavelength stability are investigated and quantified for a critical DOF layer. Besides the typical CD implications we evaluate the "image placement error" (IPE) affecting specific asymmetric patterns in the device layout. We show that the IPE of asymmetric device patterns can be sensitive to laser bandwidth, potentially resulting in nanometer-level errors in overlay. These effects are compared to the relative impact of other parameters that define the contrast of the lithography image for the 45nm node. We extend the discussion of the contributions to IPE and their relative importance in the 32 nm double-patterning overlay budget.

The influence of asymmetric spectrum of DUV light on imaging performance in advanced technology nodes

“…For high-volume manufacturing at advanced nodes, scanner vendors are still relentlessly studying all the interactions between device parameters and lithography to identify potential improvement possibilities. As demonstrated in previous studies [1][2][3][4][5][6][7][8][9][10][11][12], a significant improvement to multiple patterning solutions can be achieved by leveraging light source capabilities. Key performance indicators of a light source include control of energy, wavelength, bandwidth, etc.…”

Optimum ArFi laser bandwidth for 10nm node logic imaging performance

“…Technology Overlay and Focus budged prediction [6] For multiple patterning based Logic devices, the optimal printability is not only driven by the optimization of the optical proximity correction (OPC), but also by complex process factors, such as resist, exposure tool, and mask-related error performance levels. In addition the light source plays a crucial role; it has been widely demonstrated [7][8][9][10][11] how changes in the E95 bandwidth can significantly lead to changes in on wafer patterning due image contrast changes.…”