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Fully Recessed Oxide Isolation Planarization Without the Dip Normally Found in Wide Areas

IP.com Disclosure Number: IPCOM000038704D
Original Publication Date: 1987-Feb-01
Included in the Prior Art Database: 2005-Jan-31
Document File: 2 page(s) / 61K

Publishing Venue

IBM

Related People

Ogura, S: AUTHOR [+3]

Abstract

A method has been developed for curtailing the dip which occurs in wide open areas of semiconductor devices during fully recessed oxide isolation planarization. The new approach uses a re-flow glass as the planarization fill material and a mask to remove excess material so planarization can take place in a short time, avoiding removal of the material which contributes to the dip. In previous methods, planarizing material 1 (Fig. 1) was deposited to fill both wide 2 and narrow 3 openings. The planarization step normally effectively planarizes the narrow opening, but the wide opening is subject to a dip 4 (Fig. 2). A process step to avoid this in (Image Omitted) volves covering the wide area with an etch stop material 5 (Fig. 3), using a mask 6 to pattern it and then have it polished.

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Fully Recessed Oxide Isolation Planarization Without the Dip Normally Found in Wide Areas

A method has been developed for curtailing the dip which occurs in wide open areas of semiconductor devices during fully recessed oxide isolation planarization. The new approach uses a re-flow glass as the planarization fill material and a mask to remove excess material so planarization can take place in a short time, avoiding removal of the material which contributes to the dip. In previous methods, planarizing material 1 (Fig. 1) was deposited to fill both wide 2 and narrow 3 openings. The planarization step normally effectively planarizes the narrow opening, but the wide opening is subject to a dip 4 (Fig. 2). A process step to avoid this in

(Image Omitted)

volves covering the wide area with an etch stop material 5 (Fig. 3), using a mask 6 to pattern it and then have it polished. In this manner the narrow areas are polished while the wide areas are protected from any dip developing. The proposal is a much simpler method. A re-flow glass is used as the planarization fill material 1 (Fig. 4), with it also covering wide Si mesas 7. A mask 8 (Fig. 5) is used to etch some of the planarization material deposited over the wider mesas
7. This "pre-removal" of the material covering the mesas means a shorter planarization time will be required for the final step and less topography to be planarized after re-flow. The resist is removed and the glass 1 (Fig. 6) re- flowed by heating....