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Browse Prior Art Database

Trench Fill Process

IP.com Disclosure Number: IPCOM000043445D
Original Publication Date: 1984-Sep-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 2 page(s) / 85K

Publishing Venue

IBM

Related People

Moritz, H: AUTHOR [+3]

Abstract

The described process serves to fill trenches, etched into a semiconductor substrate, with a passivating material. During its implementation, the etch mask is preserved until the trenches have been filled, so that the step between the surface of a passivating layer on the substrate and the surface of the passivating material is kept small. Fig. 1 is a cross-sectional view of a substrate 1 coated with a layer 3 of a first isolating material, such as silicon dioxide, and comprising a via hole 2 and a trench 6 extending into substrate 1. A thin layer 4 of a second isolating material, such as silicon nitride, covers layer 3. The whole surface of the structure, except trench 6, is covered with a layer 5 of, say, silicon dioxide, which has previously been used as an etch mask to form trench 6.

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Trench Fill Process

The described process serves to fill trenches, etched into a semiconductor substrate, with a passivating material. During its implementation, the etch mask is preserved until the trenches have been filled, so that the step between the surface of a passivating layer on the substrate and the surface of the passivating material is kept small. Fig. 1 is a cross-sectional view of a substrate 1 coated with a layer 3 of a first isolating material, such as silicon dioxide, and comprising a via hole 2 and a trench 6 extending into substrate 1. A thin layer 4 of a second isolating material, such as silicon nitride, covers layer 3. The whole surface of the structure, except trench 6, is covered with a layer 5 of, say, silicon dioxide, which has previously been used as an etch mask to form trench 6. At this stage, the structure is blanket-coated with a passivating material 7, such as polyimide (Fig.
2). Subsequently, material 7 is removed from the upper surface of the structure such that is is left only in trench 6 (Fig. 3). Overetching is necessary to completely remove material 7 from the upper surface. As a result of overetching, material 7 does not completely fill trench 6. In the next step, layer 5 is removed by etching (Fig. 4). As layer 5 is removed, the step between the upper surface of the structure and the top of material 7 is small. If then, as shown in Fig. 5, a metal layer 8 is blanket-deposited on the structure, a continuous and sufficiently ...