1. Field of the Invention
Embodiments of the invention generally relate to a method and an apparatus for treating of substrate polishing fluids, such as electrochemical mechanical polishing fluids.
2. Description of the Related Art
In the fabrication of integrated circuits, displays, and other electronic devices, multiple layers of conductive, semi-conductive, and dielectric materials are deposited on or removed from a feature side of a substrate. During the fabrication process, electrochemical mechanical polishing (ECMP) and chemical mechanical polishing (CMP) are performed to polish or planarize the feature side of the substrate, and to remove defects, such as scratches, surface roughness, and contaminants from the substrate.
ECMP and CMP are two processes used to remove materials from the feature side of the substrate. In a typical CMP process, the substrate is urged against a processing pad and a fluid medium is provided at the interface between the processing pad and the substrate. The fluid medium may contain abrasive particles suspended in the fluid medium containing a chemical etchant, among other chemicals. Similarly, in a typical ECMP process, the substrate is urged against a processing pad and a fluid medium is provided at the interface between the processing pad and the substrate. In this case, the fluid medium may function as an electrolyte to facilitate electrochemical dissolution of materials on the substrate, as one or both of the substrate and processing pad are coupled to electrical power.
In both of these processes, an effluent of used processing fluid may be released from the polishing process. The effluent may contain abrasive particles, metal particles, metal ions, polishing byproducts, reagents, suspension liquid, and solvents. The effluent may also contain organic and inorganic compounds, buffering agents, oxidizers, surfactants, chelating agents, etchants, corrosion inhibitors, acids, salts, complexing agents, among other substances. The metal particles and/or metal ions may include copper, aluminum, tungsten, and other metals that may be used to form electronic devices on substrates.
If a user of an ECMP or CMP process desires to dispose of this effluent, these substances need to be removed prior to disposal. Particularly, the Environmental Protection Agency (EPA) requires removal of hazardous materials from these effluents prior to disposal. In some applications, a user may desire to capture at least a portion of the effluent and treat the effluent for reuse in the processing system.
There have been some systems developed for treating processing effluents, and/or systems for removal or abatement of substances from the processing effluent prior to disposal. However, these systems are typically provided to treat and/or facilitate removal of a particular portion of the effluent such that the processing effluent is treated in a piecemeal manner. For example, ion removal may be provided by an ion exchange medium, but the presence of chemical complexes and/or insoluble compounds in the effluent may disallow ion exchange. Thus, the effluent must be filtered and/or pretreated in another treatment apparatus prior to introduction to the ion exchange medium. Another disadvantage of the treatment stems from the effluent treatment devices being stand-alone or “off-tool” devices requiring transport of the effluent to various separate devices and intermittent storage of the effluent between treatments, which may increase downtime of the tool and/or increase operating costs of the system.
Therefore, there is a need for a method and integrated apparatus for point of use treatment of processing effluent from a polishing system.