Signal analysis of CMP process based on AE monitoring system

Abstract

As chemical mechanical planarization (CMP) enables local and global planarization over a wafer surface by the combined effects of chemical and mechanical interactions, process monitoring is becoming an increasingly important in-situ methodology for process control. According to the materials and process, signal characteristics were distinguishable between material and process. In this study, an acoustic emission (AE) sensor was used to measure the abrasive and molecular-scale phenomena during CMP. An AE signal was acquired using rotational equipment and adapted to two types of equipment. First, a wireless AE system consisting of wireless modules using Bluetooth was used. This system was suitable for acquiring signals in rotational equipment. However, a wireless AE system could be acquired with only Root Mean Square(RMS) signals. Second, mercury slip-ring (wired) AE systems that were suitable for rotational equipment and the acquisition of raw signals were used. The acquired raw signals could be analyzed by a Fast Fourier Transform (FFT) for abrasive and molecular-level phenomena in the CMP process. The AE signal parameters including the AE RMS, frequency, and amplitude were analyzed for abrasive and molecular-level phenomena in the CMP process. The authors analyzed the AE signals for changes in the materials and CMP process.

Research on Sandstone Damage Characteristics and Acoustic Emission Precursor Features under Cyclic Loading and Unloading Paths

“…It is straightforward and rapid to process the AE waveform signal using fast Fourier spectrum analysis (FFT), which transforms the frequency domain of the AE signal [48,49]. The evolution of the amplitude and frequency of the AE signal can be clearly obtained, and the spectral characteristics of the AE signal can be well reflected, as shown in Figure 7 (the frequency corresponding to the peak amplitude in the spectrum is defined as the main frequency of the waveform signal).…”

Polymer Nanoparticles Applied in the CMP (Chemical Mechanical Polishing) Process of Chip Wafers for Defect Improvement and Polishing Removal Rate Response

“…The formulation of CMP slurry is a complex science in which the chemical force of the chemical ingredients been dosed in water by tuning suitable pH [21] and the In order to achieve integration for IC fabrication, as shown in Figure 1, the CMP process is used to planarize metal that is unevenly deposited on the wafer surface, allowing one to easily create orderly stacks. CMP uses a combination of chemical and mechanical forces to achieve planarization [18,19], and the difference for planarization in CMP is shown in Figure 2, in which the cross-section images depict the IC for the transistor devices and conductive copper lines on the wafer surfaces. The figure shows the results with and without chemical mechanical polishing [20].…”

Chemomechanical magnetorheological finishing: Process mechanism, research trends, challenges and opportunities in surface finishing

“…21,22 With the aid of chemical reactions, material polishing occurs due to externally applied pressure and its associated velocity across material and polishing pad. [23][24][25] The organic and inorganic chemicals used in material processing can contribute to global environmental issues; however, it can encourage the use of green technology in the CMP sector, such as minimal slurry use, non-abrasive slurry, polishing pads (with longer life) and various conditioning methods. [26][27][28] The CMP method is currently only available for circular and flat wafer geometries.…”