Polishing system and method of its use

Abstract

The invention provides a system for polishing one or more layers of a multi-layer substrate that includes a first metal layer and a second layer comprising (i) a liquid carrier, (ii) at least one oxidizing agent, (iii) at least one polishing additive that increases the rate at which the system polishes at least one layer of the substrate, wherein the polishing additive is selected from the group consisting of pyrophosphates, condensed phosphates, phosphonic acids and salts thereof, amines, amino alcohols, amides, imines, imino acids, nitriles, nitros, thiols, thioesters, thioethers, carbothiolic acids, carbothionic acids, thiocarboxylic acids, thiosalicylic acids, hydroxylates, carbonylates, carboxylates, and acids thereof, and mixtures thereof, (iv) at least one stopping compound, and (v) a polishing pad and / or an abrasive. The invention also provides a method of polishing a substrate comprising contacting a surface of a substrate with the system and polishing at least a portion of the substrate therewith. Moreover, the invention provides a method for polishing one or more layers of a multi-layer substrate that includes a first metal layer and a second layer comprising (a) contacting the first metal layer with the system, and (b) polishing the first metal layer with the system until at least a portion of the first metal layer is removed from the substrate.

Description

field of invention [0001] The invention relates to a polishing system and a method for polishing a substrate, in particular to a method for polishing a multilayer substrate including a first metal layer and a second layer. Background of the invention [0002] Integrated circuits are fabricated from millions of active devices formed in or on a substrate such as a silicon wafer. The active devices are chemically and physically connected to a substrate and interconnected through the use of multilayer connection layers to form functional circuits. A typical multilayer interconnect includes a first metal layer, an intervening dielectric layer, and sometimes third and subsequent metal layers. Using interlayer dielectrics such as doped and undoped silicon dioxide (SiO 2 ) and / or low-k dielectrics to electrically isolate different metal layers. [0003] Metal vias are used to achieve electrical connections between different interconnect layers. For example...