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Browse Prior Art Database

Selective Planarization Process and Structures

IP.com Disclosure Number: IPCOM000043775D
Original Publication Date: 1984-Sep-01
Included in the Prior Art Database: 2005-Feb-05
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Bennett, RS: AUTHOR [+4]

Abstract

A non-critical reactive ion etch (RIE) etch-back step is used to simply expose polysilicon present on horizontal surfaces such that subsequent removal of the polysilicon can be accomplished through a simple wet or dry selective etch. The significant problem which is solved using this technique is the elimination of need for complicated back polishing techniques employing RIE and chemical mechanical polishing to remove the silicon on the horizontal oxide surfaces. The major structures and general process discussed in this article are shown in Figs. 1-6. The general intent of the structures and process is to form or deposit a material 14 in a recess (e.g., a trench) formed in a semiconductor 10, such as silicon, as shown in the figures and then to protect this material 14 with another material 15, e.g.

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Selective Planarization Process and Structures

A non-critical reactive ion etch (RIE) etch-back step is used to simply expose polysilicon present on horizontal surfaces such that subsequent removal of the polysilicon can be accomplished through a simple wet or dry selective etch. The significant problem which is solved using this technique is the elimination of need for complicated back polishing techniques employing RIE and chemical mechanical polishing to remove the silicon on the horizontal oxide surfaces. The major structures and general process discussed in this article are shown in Figs. 1-6. The general intent of the structures and process is to form or deposit a material 14 in a recess (e.g., a trench) formed in a semiconductor 10, such as silicon, as shown in the figures and then to protect this material 14 with another material 15, e.g., photoresist, while peripheral materials, such as 13 and 12, are selectively removed to leave 15, as shown in Fig. 5. Material 13 functions to create a buffer layer and step for the partial RIE (dotted line, Fig. 3) etch-back. The RIE etch-back in 15 functions to expose layer 13, but not expose 14, to allow 12 and 13 to be selectively removed. Layer 12 can also function to provide discontinuity (or extreme thinning) between materials 13 and 14 and as a nucleation layer or wetting surface for 13 such that 13 will be selectively deposited. Layer 11 indicates an additional layer or combination of layers that is used, for instance, in isolation structures, such as SiO2 and Si3N4 . Materials 13 and 14 would in most cases be deposited simultaneously; however, this need not be the case. The examples given in the direct applications of this invention include growth of epitaxial silicon for 14 and polysilicon for 13, and glasses, such as Corning 7723, for both 13 and 14. Materials 13 and 14 in the examples are essentially the same materials. However, they could be different and be formed for other extensions of the invention prior to the trench formation, and...