Toward Smart Manufacturing By Introducing Redundancy to Analytical Systems for Controlling of Damascene and 3D Packaging Electrodeposition Processesa
Authors: Jaworski Aleksander , Rapecki Tomasz , Wikiel Kazimierz 
Published: December 2024

Accurate monitoring of the chemical composition of electrodeposition baths used in semiconductor manufacturing of interconnects in integrated circuits and 3D packaging is of fundamental importance. It achieves cost minimization and satisfies process specifications regarding feature filling and morphology control for manufacturing of electronic components. To meet the Smart Manufacturing/Industry 4.0 standards, the currently-implemented process control methods need to undergo a thorough revision of their analytical approach and configuration capabilities. The chief prerequisites for upgrading to Smart Manufacturing/Industry 4.0 standards include a combination of reliability, stability of performance over time; simplicity of design; no consumables and low maintenance. The imperative factor guaranteeing a reliable, uninterrupted process control data flow is the analytical system’s redundancy. Additionally, the future Industry 4.0 compliant analytical systems must significantly reduce or completely eliminate the need for reagents or chemical operations and must not generate hazardous waste as a move toward environmentally friendly green technologies.

Most of the currently used automated analytical systems for monitoring electroplating solutions in damascene and 3D packaging processes are of complex design. Typically, they consolidate numerous zero- and first-order analytical instruments employing fundamentally different methods such as titration, chromatography, spectrometry, and electroanalysis in a single, integrated unit. These complicated analytical systems require sophisticated plumbing and multiple sensors. Such a high degree of complexity adversely affects their reliability. The majority of sensors used for monitoring of electroplating solution needs to be frequently (daily or in some cases before each measurement) calibrated. This requires additional chemical standards, and increases the complexity of the entire hardware, and inflates the dimensions of the analytical system. Such a spatial burden is of critical importance in the majority of production areas and practically eliminates any notion about creating a system’s redundancy. The compactness of an analytical system is a prerequisite to consider its multiplication toward achieving the redundancy.

The metrology presented in this paper features a mechanically-simple and compact device that is widely used for plating bath control. Its small-size electroanalytical sensor can be submersed in the plating bath tank without disrupting the damascene or 3D packaging electrodeposition process operation. The integrated, in-situ sensor is capable of monitoring all components solely by utilizing electroanalytical techniques including DC and multi-frequency AC voltammetry. Superimposing of several sinusoidal perturbations of various frequencies and amplitudes on DC waveform upgrades the first-order instrument to the second order without compromising the time of analysis. The solution sample is analyzed without any pretreatment and returned unaltered into the plating tank upon the conclusion of the measurement with no waste being created. This approach provides a total insight into a plating bath by uniquely combining advanced DC and AC voltammetric measurements with extensive application of chemometric techniques. Multiway chemometrics is utilized not only for concentration prediction but also for fault detection and classification (FDC). The consolidation of all analytical functions into a single, compact sensor allows for redundancy, without compromising spatial and temporal limitations. The resulting multiple advantages of operational redundancy relevant to damascene and 3D packaging electrodeposition process control will be presented.