Method of forming thin metal films on substrates

Abstract

A solution containing a metal component of composite ultrafine metal particles each having a core substantially made of metal component and a covering layer made of an organic compound chemically bonded to the core having an average diameter ranging from 1 to 10 nm, uniformly dispersed in a solvent, forms a thin metal film on the surface of a transfer sheet, after which the transfer sheet is thermally decomposed to transfer the thin metal film to a substrate.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a solution containing a metal component, and a method of and an apparatus for forming a thin metal film, and more particularly to a solution containing a metal component for use in forming a conductive thin metal film on a semiconductor substrate of silicon or the like, and a method of and an apparatus for forming a thin metal film using such a solution, and a method of and an apparatus for forming a thin metal film in embedding a conductive metal such as copper (Cu) or the like in minute interconnection recesses defined in the surface of a substrate of silicon or the like thereby forming interconnections. [0003] 2. Description of the Related Art [0004] Aluminum or aluminum alloys are generally used as metal materials for forming interconnection circuits on semiconductor substrates. One recent trend is to use copper as such a metal material for forming interconnection circuits. Since...

AI Technical Summary

Benefits of technology

The present invention provides a solution containing a metal component, which can be easily and inexpensively formed and can be adjusted in conductivity and thickness. The solution contains composite ultrafine metal particles with a core made of a metal component and a covering layer made of an organic compound chemically bonded to the core. The particles have a small size and can be uniformly dispersed in a solvent. The solution can be used to form a thin metal film on a substrate by evaporating the solvent and thermally decomposing the coating layer. The method is simple and can be carried out with a low-level vacuum system.

Problems solved by technology

While the plating technology is inexpensive and technically highly complete, the electrolytic plating process allows films to be grown on only conductive materials, and the electroless plating process is open to environmental pollution as materials contained in the plating solution adversely affect the natural environment and the working and labor environment.

If a thin metal film is formed of a conventional metal paste as interconnections on a ceramic substrate, then the conductivity is limited to a certain level because the thin metal film is rendered conductive by point-to-point contact between metal particles.

The thicker metal film is more expensive to manufacture.

However, available processes of producing ultrafine metal particles are of low productivity.

The processes of producing ultrafine metal particles also disadvantageous in that it is difficult to keep the ultrafine particles in safe storage because once the solvent is evaporated, the particles stick to each other and cannot be reused.

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