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Device for Planarizing Structured Surfaces

IP.com Disclosure Number: IPCOM000036597D
Original Publication Date: 1989-Oct-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Boettiger, U: AUTHOR

Abstract

Lithographically structured surfaces, for example, of semiconductor substrates, frequently have a substantial three-dimensional topography. As a result of the limited depth of focus of presently used high-resolution optical exposure devices, such surfaces cannot be accurately structured any further until after they have been planarized by an additive method providing for a curable and/or moldable compound, such as a polyimide or a photoresist, to be deposited and cured between the surface to be treated and an absolutely planar ram. After withdrawal of the ram, a planar surface is obtained.

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Device for Planarizing Structured Surfaces

Lithographically structured surfaces, for example, of semiconductor substrates, frequently have a substantial three-dimensional topography. As a result of the limited depth of focus of presently used high-resolution optical exposure devices, such surfaces cannot be accurately structured any further until after they have been planarized by an additive method providing for a curable and/or moldable compound, such as a polyimide or a photoresist, to be deposited and cured between the surface to be treated and an absolutely planar ram. After withdrawal of the ram, a planar surface is obtained.

For planarization, the surface to be planarized is pressed against a planar reference surface of the ram. For this purpose, the compound is spun onto the substrate, subsequently applying the heatable/coolable ram, or the ram is provided with apertures through which the compound is directly applied to the surface. In both cases, the compound is cured while the ram continues to be pressed against the surface to prevent any changes to the latter. The ram may also rotate along with the substrate and be moved slowly against the substrate while the compound is applied by spinning. Irrespective of the approach used, small spacer areas on the substrate or the reference surface ensure an accurate layer thickness of the compound which is kept constant across the entire surface. For producing semiconductors, the spacer areas may be positioned, fo...