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Sacrificial dielectric HM for TfmHM integration in the BEOL

IP.com Disclosure Number: IPCOM000231854D
Publication Date: 2013-Oct-09
Document File: 2 page(s) / 40K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for the subsequent removal of the dielectric hard-mask layer after selectively removing the metal hard-mask in an Ultra Low-K (ULK) dielectric.

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Title

Sacrificial dielectric HM for TfmHM integration in the BEOL

Abstract

Disclosed is a method for the subsequent removal of the dielectric hard-mask layer after selectively removing the metal hard-mask in an Ultra Low-K (ULK) dielectric.

Problem

Dielectric hard-mask layers are required as Ultra Low-K (ULK) protection and are used to control the recess during Trench First Metal Hard Mask (TfmHM) patterning. Inter-Layer Dielectric (ILD) hard-mask has undesired effects on the ULK dielectric. ILD complicates the trench and via profile control (undercut due to different etch selectivity). It increases the trench and via aspect ratio and thus complicates metallization (copper fill). In addition, it requires an additional component to polish variations due to different polish rates compared to the ULK dielectric.

Solution/Novel Contribution

The solution is a method for the subsequent removal of the dielectric hard-mask layer after selectively removing the metal hard-mask. The removal of both hard- mask layers could also happen simultaneously with an appropriate wet-clean chemistry. The method integrates dielectric hard-mask material with high wet- etch rate compared to ULK (e.g., Silane based nitride with very high HF etch rate).

Method/Process

Figure: Steps (1-6) for subsequent removal of the dielectric hard-mask layer after selectively removing the metal hard-mask


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Conclusions

No additional dry etch is required, saving thus costs and avoiding extra dam...