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Semiconductor Metalizing Process

IP.com Disclosure Number: IPCOM000093440D
Original Publication Date: 1967-Sep-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 3 page(s) / 39K

Publishing Venue

IBM

Related People

Hatzakis, M: AUTHOR

Abstract

In the manufacture of semiconductors or integrated circuits, metalization is one of the final steps required to make electrical contact to the various parts of the device or circuit.

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Semiconductor Metalizing Process

In the manufacture of semiconductors or integrated circuits, metalization is one of the final steps required to make electrical contact to the various parts of the device or circuit.

At present, metalization is accomplished by evaporation or sputtering of the required metal over the entire surface of the wafer containing the devices or circuits. This is followed by coating with a suitable photo or electron resist which can be exposed according to a predetermined pattern corresponding to the details of the devices or circuits to be metalized. The photoresist is thus removed over the parts of the unwanted metal and the exposed metal is chemically etched away in a suitable bath.

The main disadvantages of this method are that the edge resolution of the metalization pattern is limited by nonuniform etching rates. The thickness/width ratio is limited by undercutting effects. This is particularly true with aluminum metalization used in most semiconductor and integrated circuit fabrications. Poor edge resolution imposes a limit on the minimum line width that can be etched reliably to over one micron, depending on the height of the metalization layer. As a result of this, very high-speed transistors and integrated structures requiring metalization strips of width less than one micron can not be produced reliably using metal etching techniques.

This method produces lines of extremely small width with nearly perfect edge resolution and unity thickness/width ratios, using any metal or insulator since no etching is involved. The process employs a positive electron resist and consists of coating the entire wafer surface with resist, exposing and removing the portions over which metalization is required and evaporating the metal on the substrate thr...