Method and apparatus for monitoring, dosing and distribution of chemical solutions

Abstract

It is an object of the present invention to provide a system and method for monitoring, dosing and distribution of a chemical composition in a material treatment process, the chemical composition containing at least one additive for maintaining quality of the chemical treatment process. The system and method include: at least one chemical containing unit configured to contain the chemical composition for the chemical treatment process; a dosing unit fluidly communicating with the at least one chemical containing unit configured to receive the chemical composition therefrom and to add a selected dose of the at least one additive to the chemical composition therein; an online monitor configured to monitor a property of the chemical composition at the dosing unit and to transmit a signal corresponding to the monitored property; and a controller programmed and configured to receive the signal from the online monitor and send a signal to the dosing system to add the selected dose to the chemical composition therein in response to the monitored property.

Description

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT Not applicable. REFERENCE TO SEQUENTIAL LISTING Not applicable. BACKGROUND OF THE INVENTION 1) Field of the Invention This invention is directed to the field of management of chemical compositions used in material treatment processes. This invention is particularly directed to the field of management of electroplating bath solutions. 2) Description of the Related Art Many material treatment processes utilize a chemical composition. In order to smoothly operate such a process, upsets or deviations in the quality of the chemical composition should be avoided. Otherwise, quality of the treated material will vary over time. Also, the process might need to be shut down in order to bring the quality of the chemical composition back into the specification of the process. Such a shutdown is often prohibitively expensive. Some examples of material treatment processes include chemical mechanical polishing / planarization (CM...

AI Technical Summary

Benefits of technology

It is an object of the present invention to provide a system for monitoring, dosing and distribution of a chemical composition in a material treatment process, the chemical composition containing at least one additive for maintaining quality of the chemical treatment process. The system comprises: at least one chemical containing unit configured to contain the chemical composition for the chemical treatment process; a dosing unit fluidly communicating with at least one chemical containing unit configured to receive the chemical composition therefrom and to add a selected dose of at least one additive to the chemical composition therein; an online monitor configured to monitor a property of the chemical composition at the dosing unit and to transmit a signal corresponding to the monitored property; and a controller programmed and configured to receive the signal from the online monitor and send a signal to the dosing system to add the selected dose to the chemical composition therein in response to the monitored property.

It is another object to provide a method for monitoring, dosing and distribution of a chemical composition in a chemical treatment process, the chemical composition containin

Problems solved by technology

Such a shutdown is often prohibitively expensive.

One of the main limitations of CVS is its sensitivity to matrix effects of the electrolyte, since the copper stripping is dependent not only on the individual additives but also their interaction and degradation in the bath solution [Sun, Zhi-Wen and Dixit, Girsih, “Optimized bath control for void-free copper deposition”, Solid State Technology, November, 2001, pp.

Also, measurement time tends to be long (several hours) and large volumes of electrolytes are used, increasing the consumption and waste stream of these expensive chemicals.

High performance liquid chromatography (HPLC) also generates large amounts of waste and also has a relatively long response time.

One limitation to many of these methods is that plating bath breakdown products are not measured, although they are critical to determining bath quality.

Others recognize that open-loop control fails to correct for local variations in consumption associated with plating fluctuations or changing bath equilibrium as degradation products are formed [Bratin P., Chalyt G., Pavlov M., “Control of Damascene Copper Processes by Cyclic Voltammetric Stripping, Plating & Surface Finishing, March 2000, pp.

Also, these types of models are likely only valid in the vicinity of a known operating regime and have limited ability to accommodate process upsets or disturbances.

Since open loop control does not detect process changes as it assumes steady-state operation, it could eventually lead to serious copper interconnects defects.

However, current online bath component analysis is performed in 20-40 minutes depending on the type of equipment, which is not quite “real-time”.

In addition, communication of the online monitor to the dosing system of commercial plating tools is not yet automatic and requires development of communication protocols to effectively use the process signal to control the bath concentrations.

However, depending on wafer plating production levels, additive bottles may need to be changed quite frequently at the tool, which increases the risk of operator error and contamination (for example, from an incorrect bottle exchange).

For those tools that do not integrate online monitoring with the tool, they are disadvantageous because they require process engineer intervention to correct the bath concentrations.

Since each tool is controlled separately, inconsistencies in the bath solution between tools can develop which can ultimately result in different properties of the copper interconnect deposit for different tools.

Images