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Fabrication Process for Buried Metal Line Configurations

IP.com Disclosure Number: IPCOM000082058D
Original Publication Date: 1974-Sep-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 3 page(s) / 62K

Publishing Venue

IBM

Related People

Berkenblit, MK: AUTHOR [+3]

Abstract

Described is a.process for fabricating an improved buried metal line configuration for use in gas panels. The shape of the metal lines which are formed in shallow etched grooves (sharp corners) and the space between the metal line and the edge of the shallow groove, causes fabrication difficulties. The sharp corners of metal lines act as a stress point for the subsequent dielectric and have resulted in cracks in the dielectric layer. The channels which remain between the etched lines and the edge of the shallow etched groove are never completely filled by the overlying dielectric layer, which then results in a possible leak path. The process described herein shapes the edges of the metal lines and fills the space between the line and the groove wall.

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Fabrication Process for Buried Metal Line Configurations

Described is a.process for fabricating an improved buried metal line configuration for use in gas panels. The shape of the metal lines which are formed in shallow etched grooves (sharp corners) and the space between the metal line and the edge of the shallow groove, causes fabrication difficulties. The sharp corners of metal lines act as a stress point for the subsequent dielectric and have resulted in cracks in the dielectric layer. The channels which remain between the etched lines and the edge of the shallow etched groove are never completely filled by the overlying dielectric layer, which then results in a possible leak path. The process described herein shapes the edges of the metal lines and fills the space between the line and the groove wall.

The process carried out by the following steps is described using aluminum lines and is illustrated by Figs. 1, 2, 3, 4a, 4b, 5a, 5b, 6a and 6b:
Step 1. Etch grooves on glass substrate using a photoresist as shown in Fig. 1.

Step 2. With the right choice of photoresist for step 1 (so that a small photoresist overhang results

after etching the groove), aluminum (Al) is deposited

(by any suitable method) over the entire surface. The

photoresist and Al are then blister peeled off leaving

the grooves filled with Al (Fig. 2). The Al layer

that is deposited should be somewhat thinner than

the depth of the groove.

Step 3. An alternate method of forming the Al lines is shown in Figs. 3, 4a and 4b. After etching the grooves, the

photoresist is stripped. A blanket Al layer is deposited

to a thickness which is slightly greater than the depth

of the etched grooves. Excess Al is removed by

electrolytic etching (85% phosphoric acid

acid at room temperature). Electrolytic etching of the

Al in the grooves will terminate

when the thin-metal layer coverage at the edges of the

grooves has been etched through (Fig. 4a), isolating the

buried lines from the rest of the Al layer. The buried

Al then etches chemically while the remaining Al

continues to etch elec...