Self-aligned fuse structure and method with heat sink

Abstract

Abstract Provided are a self-aligned semiconductor fuse structure, a method of making such a fuse structure, and apparatuses incorporating such a fuse structure. The fuse break point, that point at which the electrical link of which the fuse is part is severed by a laser beam, is self-aligned by the use of photolithographically patterned dielectric and a heat sink material. The self-alignment allows the size and location of the break point to be more forgiving of the laser beam size and alignment. This has several advantages, including allowing photolithographic control and effective size reduction of the laser spot irradiating the fuse material and surrounding structure. This permits reduced fuse pitch, increasing density and the efficiency of use of chip area, and results in reduced thermal exposure, which causes less damage to chip. In addition, laser alignment is less critical and therefore less time-consuming, which increases throughput in fabrication. The present invention exploits the characteristic of most dielectric materials that they are poor conductors of thermal energy. Thermal resistance increases with the thickness of the dielectric. Thus that heat is conducted more easily and thus quickly through a relatively thin portion of dielectric than it is through a relatively thick portion of dielectric. In alternative embodiments, the present invention also exploits the characteristic of a dielectric material that its reflectance changes with its thickness due to optical interference effects. In such embodiments, the self-alignment of the fuse break point is further facilitated by the use of photolithography and anti-reflective coatings.

Inventors

• 👤 Gary K. Giust
• 👤 Ruggero Castagnetti
• 👤 Yauh-Ching Liu
• 👤 Subramanian Ramesh

Bibliographic Details