Background: Although the wet cleaning process has been widely used in semiconductor device manufacturing due to its convenience, it faces theoretical limits. That is, when the size of the objected particle is smaller than 100 nm, it is buried in the stagnant layer where there is substantially no fluid flow. Aim: Only small particles below the stagnant layer (<100 nm) is removed without any damage to the fine patterns or substrate: pattern collapse, critical dimension shift, and optical property shift. Approach: Utilizing unique characteristics of water: volume expansion when freezing, solid (ice) is lighter than liquid (water), and particles adhered the substrate is peeled off from the substrate and rise to the water surface along with the surrounding ice. Results: By repeating the cycle of cooling, thawing, and rinsing, polystyrene sphere particle of 80 nm in diameter can be removed with high particle removal efficiency (PRE >90 % ) and no negative influences on the pattern or substrate. Conclusions: A new cleaning method for very small (<100 nm) particles is proposed with high PRE and low damage. This method is thought to be applied to every process if water can infiltrate into the gap between the particles and the substrate.

中文翻译：

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颗粒和图案判别冷冻清洗方法

背景：尽管湿法清洁工艺由于其方便性而被广泛用于半导体器件的制造中，但它仍面临着理论上的限制。即，当目标粒子的尺寸小于100nm时，其被掩埋在基本没有流体流动的停滞层中。目的：仅去除停滞层（<100 nm）以下的小颗粒，而不会损坏精细图案或基板：图案塌陷，临界尺寸偏移和光学特性偏移。方法：利用水的独特特性：冷冻时体积膨胀，固体（冰）比液体（水）轻，粘附在基材上的颗粒从基材上剥离，并与周围的冰一起上升到水面。结果：通过重复冷却，解冻和冲洗的循环，直径为80 nm的聚苯乙烯球颗粒可以高效去除（PRE> 90％），并且不会对图案或基材产生负面影响。结论：提出了一种新的清洗方法，该方法可清洗非常小（<100 nm）且具有高PRE和低损伤的微粒。如果水可以渗透到颗粒和基材之间的间隙中，则认为该方法适用于每个过程。