Decoupled complementary mask patterning transfer method

Abstract

A patterning method allows for separate transfer of a complementary reticle set. In one embodiment, for example, the method includes etching a phase shift mask (PSM) [112], then etching a cut mask for a cPSM mask (110). Moreover, a decoupled complementary mask patterning transfer method includes two separate and decoupled mask patterning steps which form combined patterns through the use of partial image transfers into an intermediate hard mask (112) prior to final wafer patterning. The intermediate (112) and final hard mask (110) materials are chosen to prevent image transfer into an underlying substrate (102) 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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