METHOD OF MANUFACTURING SEMICONDUCTOR DEVICE

Abstract

A method of manufacturing a semiconductor device having a back surface electrode, including: a step of preparing a semiconductor wafer having a front surface and a back surface; a thermal processing step of forming a first metal layer on the back surface of the semiconductor wafer and executing thermal processing, thereby creating an ohmic contact between the semiconductor wafer and the first metal layer; and a step of forming a second metal layer of Ni on the back surface of the semiconductor substrate after the thermal processing step.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A through 1E show cross sectional views of steps of manufacturing a semiconductor device according to an embodiment 1 of the present invention;

FIGS. 2A through 2E show cross sectional views of steps of manufacturing a semiconductor device according to an embodiment 2 of the present invention;

FIGS. 3A through 3E show cross sectional views of steps of manufacturing a semiconductor device according to an embodiment 3 of the present invention;

FIG. 4 is a top view of a conventional semiconductor device;

FIGS. 5A through 5D show cross sectional views of conventional steps of manufacturing a semiconductor device; and

FIG. 6 shows a relationship between the wafer thickness and the amount of bending in a semiconductor device fabricated in accordance with a conventional manufacturing method.

Claims

1. A method of manufacturing a semiconductor device having a back surface electrode, comprising: a step of preparing a semiconductor wafer having a front surface and a back surface;a thermal processing step of forming a first metal layer on said back surface of said semiconductor wafer and executing thermal processing, thereby creating an ohmic contact between said semiconductor wafer and said first metal layer; anda step of forming a second metal layer of Ni on said back surface of said semiconductor substrate after said thermal processing step.

2. The manufacturing method according to claim 1, wherein a barrier metal layer is formed after said thermal processing is performed, and then said second metal layer is formed on said barrier metal layer.

3. The manufacturing method according to claim 1, wherein a barrier metal layer is formed on said first metal layer, and then said thermal processing is performed, and after said thermal processing said second metal layer is formed on said barrier metal layer.

4. The manufacturing method according to claim 1, wherein a barrier metal layer is formed on said first metal layer, and then said thermal processing is performed, and after said thermal processing said barrier metal layer is further additionally formed on said barrier metal layer and said second metal layer is formed on said barrier metal layer.

5. The manufacturing method according to claim 1, wherein said first metal layer is made of a material which is selected from the group consisting of Al and Al—Si alloy.

6. The manufacturing method according to claim 1, wherein the step following said thermal processing step is performed while maintaining the temperature of said semiconductor wafer at a lower temperature than the temperature which is used at said thermal processing step.