Decoupled complementary mask patterning transfer method

Abstract

A patterning method that allows for the individual transfer of complementary reticle sets. In one embodiment, for example, the method includes etching a phase shift mask (PSM) and then etching a dicing mask for a cPSM mask. Furthermore, the split-complementary mask pattern transfer method includes two independent and separate mask patterning steps to form a combined pattern by using partial image transfer to an intermediate hard mask prior to final wafer patterning. The intermediate hardmask and final hardmask materials are chosen to prevent image transfer into the underlying substrate or wafer prior to the final etch process.

Description

technical field [0001] The present invention relates to semiconductor device processing, and more particularly, to a decoupled complementary mask patterning transfer method. Background technique [0002] A standard dual-mask patterning scheme, such as a complementary phase shift mask (cPSM, cPSM), needs to expose the phase shift mask and the dicing mask before etching. However, there is the advantage of transferring each mask pattern to the substrate separately. These advantages include individually adjusted exposure conditions for each mask, elimination of flare effects that cause unwanted interactions between exposures, photoresist trimming on anchored features (trimming) (before cutting the mask), and include assist features, however, these advantages may not be realized due to image coupling effects. Unfortunately, existing solutions exacerbate the vertical etch depth difference between the two mask transfers, resulting in excessive active pitting, for example, at the ...

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Problems solved by technology

These advantages include individually adjusted exposure conditions for each mask, elimination of flare effects that cause unwanted interactions between exposures, photoresist trimming on anchored features (trimming) (before cutting the mask), and the inclusion of assist features, however, these advantages may not be realized due to image coupling effects

Unfortunately, existing solutions exacerbate the vertical etch depth difference between the two mask transfers, resulting in excessive active pitting at the gate, for example

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