US 5,665,659 A · Method for forming metal layer of a semiconductor device

Abstract

A method for forming a metal layer including the steps of heat treating a semiconductor substrate for a predetermined time at an intermediate temperature between 200.degree. C. and 400.degree. C., then depositing the metal layer on the semiconductor substrate at a temperature below 200.degree. C., in a vacuum, then thermally treating the metal layer at a temperature between 0.6 Tm-1.0 Tm (where Tm is the melting point of the metal layer), without breaking the vacuum, thereby reflowing the grains of the metal layer, and then gradually cooling the metal layer. Alternatively, the intermediate heat-treatment step can be performed after the metal layer is thermally treated, in which case, the metal layer should thereafter be rapidly cooled.

Claims47

Dependent claims

A method for forming a metal layer on an underlying layer formed on a semiconductor substrate, comprising the steps of:

forming an underlying layer on a semiconductor substrate and annealing said underlying layer;
subsequent to said step of annealing, maintaining said semiconductor substrate at a first temperature which is between 200.degree. C. and 400.degree. C. for an amount of time;
following said step of maintaining, in a vacuum, depositing a metal at a second temperature on said underlying layer to form a metal layer;
heating said metal layer to a third temperature without breaking said vacuum, thereby causing reflow of grains of said metal layer;
and
following said step of heating said metal layer to said third temperature, cooling said metal layer;
wherein said second temperature is lower than said third temperature, and said first temperature is intermediate said second and third temperatures.

4 more elements

Dependencies are inferred from the claim text.

Method for forming metal layer of a semiconductor device

Life of this patent

Method for forming metal layer of a semiconductor device

Life of this patent

Abstract

Claims47