Method of increasing high-aspect ratio photoetching process windows through dual graph technology

Abstract

The invention provides a method of increasing high-aspect ratio photoetching process windows through a dual graph technology. The method comprises the following steps: photoetching process requirements are divided to a combination of twice photoetching; a first photomask is used to carry out first photoetching processing on a process graph; a second photomask is used to carry out second photoetching processing on the process graph, and wherein the process window graph formed by the combination of the first photomask and the second photomask has a pixel size meeting the process requirements andare 1D groove graph photomasks. According to the method of increasing the high-aspect ratio photoetching process windows through the dual graph technology, in view of the high-aspect ratio layer, when the pixel size is reduced gradually and a target linewidth is reduced, the dual graph technology is adopted to split a one-layer 2D point graph to a two-layer 1D groove graph, and in combination ofthe PSM photomask process mode, the high-aspect ratio layer process windows are increased.

Description

technical field [0001] The invention relates to the field of semiconductor integrated circuit manufacturing, and in particular to a method for increasing a high-aspect-ratio photolithography process window through a double patterning technique. Background technique [0002] At present, there is a photoresist layer with an aspect ratio exceeding 10:1 in the process. The purpose of this layer is to isolate the pixel area. When the ion implantation dose in the pixel area is larger, the function of the device will be stronger; at the same time, this layer is also along the The representative level of the development of "Moore's Law", the three main directions promoted by the industry: the reduction of pixel size, the reduction of key dimensions, and the thickening of photoresist. [0003] At present, the hierarchical graphic structure of existing products is a 2D DOT graphic, and the space between repeated DOTs is the key graphic of the pixel area. With the current photoresist t...

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Problems solved by technology

[0003] At present, the hierarchical graphic structure of existing products is a 2D DOT graphic, and the space between repeated DOTs is the key graphic of the pixel area. With the current photoresist thickness, the aspect ratio is greater than 10:1. Thickness, with the exposure method of 2 exposures, the process window of lithography has reached the limit and occasionally there will be abnormalities in the production line caused by insufficient lithography process window

According to the customer's process development requirements for this level, when the pixel size continues to decrease, the pattern structure of DOT is more likely to cause pattern collapse, that is, the photolithography process window is insufficient

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