Fabricating electrical metal fuses without additional masking

A method of forming an electrical metal fuse, comprising the steps of:

• providing a substrate;
• forming a first patterned dielectric layer over the substrate;
• the first patterned dielectric layer having a first opening and a second opening each exposing a portion of the substrate;
• forming a first planarized structures within the first and second openings;
• forming a second patterned dielectric layer over the first patterned dielectric layer and the first planarized structures;
• the second patterned dielectric layer having a third opening exposing at least a portion of each of the first planarized structures;
• and
• forming a second planarized structure within the third opening whereby the first planarized structures and the second planarized structure comprise the electrical metal fuse;
• the electrical metal fuse having a middle portion having a thickness and a width between two end portions each having a thickness and a width;
• the thickness and width of the middle portion being less than the respective thickness and width of the end portions.

A method of forming an electrical metal fuse, comprising the steps of:

• providing a substrate;
• forming a first patterned dielectric layer over the substrate;
• the first patterned dielectric layer having a first opening exposing at least a portion of the substrate;
• forming a first planarized structure within the first opening;
• forming a second patterned dielectric layer over the first patterned dielectric layer and the first planarized structure;
• the second patterned dielectric layer having a second opening exposing at least a portion of the first planarized structure;
• and forming a second planarized structure within the second opening whereby the first planarized structure and the second planarized structure comprise the electrical metal fuse;
• the electrical metal fuse having a middle portion having a thickness and a width between a first end portion having a thickness and a width and a second end portion having a thickness and a width;
• the thickness and width of the middle portion being less than the respective thicknesses and widths of the first and second end portions.

A method of forming an electrical metal fuse, comprising the steps of:

• providing a substrate;
• forming a first patterned dielectric layer over the substrate;
• the first patterned dielectric layer having a first opening exposing at least a portion of the substrate;
• forming a first planarized structure within the first opening;
• the first planarized structure including a middle portion, a portion of the first end and the second end of the electrical metal fuse;
• forming a second patterned dielectric layer over the first planarized structure;
• the second patterned dielectric layer having a second opening exposing at least a portion of the portion of the first end of the electrical metal fuse;
• and
• forming a second planarized structure within the second opening whereby the second planarized structure and the portion of the first end of the electrical metal fuse comprise the complete first end of the electrical metal fuse;
• whereby the middle portion of the electrical metal fuse has a thickness and a width, the first end of the electrical metal fuse has a thickness and a width and the second end of the electrical metal fuse has a thickness and a width;
• the width of the middle portion being less than the respective widths of the first and second end portions;
• the thickness of the first end being greater than the thickness of the second end of the electrical metal fuse;
• and the thickness of the second end being greater than the thickness of the middle portion of the electrical metal fuse.