Effect of Temperature on Photoresist Critical Dimension during Puddle Development

Abstract

We have investigated the effect of a temperature change on photoresist critical dimension (CD) in a wafer during puddle development. The wafer temperature was decreased by the evaporation latent heat of developer solution during puddle development, and the rate of temperature decrease of the peripheral area was higher than that of the central area in the wafer. The temperature of the peripheral area was approximately 1.3 °C lower than that of the central area after 60 s. The temperature distribution was caused by the difference in heat capacitance in the wafer, which was mainly influenced by the wafer chuck. We investigated the influence of temperature on photoresist CD in the wafer, using a diazonaphthoquinone (DNQ)/novolac photoresist. Photoresist CD changed with temperature at a rate of approximately 5 nm/°C, and the CD of the peripheral area became smaller than that of the central area over time. We can improve the CD distribution by controlling the temperature during puddle development or by using a photoresist with a dissolution rate that is less sensitive to temperature.

Resolution Limit in Plasmonic Lithography for Practical Applications beyond 2x‐nm Half Pitch

“…Since it is well known that the LER due to the polymer aggregation structure can be reduced using a proper developer solution with a small‐size molecule,34, 35 we applied a potassium hydroxide (KOH)‐based developer solution (AZ 400K) instead of a tetramethylammonium hydroxide (TMAH)‐based solution (AZ MIF 300) to the photoresist (Dongjin Semichem, DPR i‐7200P), exposed at a wavelength of 405 nm. Additionally, the development rate and the contrast curves of the developed resist are largely affected by the developing temperature 37–39. In general, it is known that the resolution can be enhanced using a photoresist with higher resist contrast 40.…”