Time-based PEB adjustment for optimizing CD distributions

Abstract

In this paper we investigate the impact of bake plate temperature variability throughout the entire bake trajectory on resulting critical dimension. For a poorly-controlled bake plate, it is found that the correlation between the temperature profile and CD distribution is high throughout the entire bake cycle, including the steady state sector. However, for a well-controlled, multiple-zone bake plate, the correlation is only significant during the transient heating sector, since in those cases the steady state plate behavior has already been optimized for CDU performance. An estimate of the potential improvement yet to be gained by improvement of transient heating uniformity is calculated.

Temperature Cycling for Photoresist Processing

“…For current generation of photoresist, the temperature of the wafer during this thermal cycle has to be controlled to a high degree of precision both spatially and temporally. A number of recent investigations also show the importance of proper bakeplate operation on CD control Friedberg, et al [2004]. The ability to control the temperature of the wafer to different setpoint is exploited in this application.…”

A lamp thermoelectricity based integrated bake/chill system for photoresist processing

“…For example, Sturtevant et al [3] reported a 9% variation in the linewidth or critical dimension (CD) per 1% variation in temperature for a deep ultraviolet (DUV) resist. A number of recent investigations also show the importance of proper bakeplate operation on CD control [5,6].…”

Critical dimension sensitivity to post-exposure bake temperature variations in EUV photoresists

“…Additional challenges are sure to emerge from the (as yet unmeasured and unspecified) photoresist sensitivity to the transient aspects of the PEB step, although recent experiments have shown that postdevelop CD is particularly sensitive to this component of the PEB process. 2 In this work we present the results of experiments performed using the static Microfield Exposure Tool (MET) printing system at the Advanced Light Source at Lawrence Berkeley National Laboratory. [3][4][5] This system uses synchrotron radiation at a wavelength of 13.5 nm and the optic has a numerical aperture (NA) of 0.3 and a field size of 600 µm 200 µm at the wafer.…”