Electron-beam-induced CD shrink techniques

Electron-beam-mediated heating and flowing of patterned resist features has been demonstrated as a viable technique for shrinking the size of contact hole and via structures to sub-90-nm dimensions, thereby overcoming the mask error factor problem of printing these features. While the CD uniformity of electron-beam-shrunk contact holes and vias is comparable to that obtained on the same structures that have not been irradiated with electron beam, the iso-dense bias does increase with the dose of electron-beam irradiation. 

The MEEF is a major problem limiting the printing of contact hole and via structures. A way of overcoming the MEEF problems of contact hole, via, and trench printing is to first lithographically pattern large sizes of such features, and 

Kunz and R.R. Dammel, 193 nm lithography fundamentals and issues, SPIE Short Course No. SC120 (2005). 

Okoroanyanwu, Process for reducing critical dimensions of contact holes, vias, and trench structures in integrated circuits, U.S. Patent No. 6,518,175 (2003) U. Okoroanyanwu, Process for reducing the pitch of contact holes, vias, and trench structures in integrated circuits, U.S. Patent No. 6,589,713 (2003). 

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