Approaches to Sustainability in Chemical Mechanical Polishing (CMP): A Review

Two-dimensional materials (2DMs) have attracted a great deal of interest due to their immense potential for scientific breakthroughs and technological innovations. While some 2D transition metal dichalcogenides (TMDC) such as MoS2 and WS2 are considered as the ultimate channel materials in unltrascaled transistors as replacements for Si, there has also been increasing interest in the monolithic 3D integration of 2DMs on the Si CMOS platform or in flexible electronics as back-end-of-line transistors, memory devices/selectors, and sensors, taking advantage of 2DM properties such as a high current driving capability with low leakage current, nonvolatile switching characteristics, a large surface-to-volume ratio, and a tunable bandgap. However, the realization of both of these scenarios critically depends on the development of manufacturing-viable high-yield 2DM layers transfer from the growth substrate to the Si, since the growth of high-quality 2DM layers often requires a high-temperature growth process on template substrates. Motivated by this, extensive efforts have been made by the 2DM research community to develop various 2DM layer transfer methods, leveraging the van der Waals transfer capability of the layer-structured 2DMs. These efforts have led to a number of successful demonstrations of wafer-scale 2D TMDC layer transfer, while 2DM-enabled template growth/transfer of some functional bulk materials such as III–V, Ge, and AlN has also been demonstrated. This review surveys and compares different 2DM transfer methods developed recently, with a focus on large-area 2D TMDC film transfer along with an introduction of 2DM template-assisted van der Waals growth/transfer of non-2D thin films. We will also briefly present an outlook of our envisioned multifunctionalities in 3D integrated electronic systems enabled by monolithic 3D integration of 2DMs and III–V via van der Waals transfer and discuss possible technology options for overcoming remaining challenges.

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Section: Outlook and Perspectivementioning

confidence: 99%

Van der Waals Layer Transfer of 2D Materials for Monolithic 3D Electronic System Integration: Review and Outlook

Kim

Ang

et al. 2023

ACS Nano

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“…The rates of oxide removal differ depending on the applied load, the removal depth, and the slurry used. There is extensive research on the CMP process, but for a better understanding of the mechanical and tribochemical phenomena, additional studies are needed that appear at the interface of the pad–wafer (selective layer) in the presence of fluid slurry [ 1 , 2 , 3 , 4 , 5 ]. The studies carried out by Ilie [ 1 ] and Lee et al [ 2 ] showed that the formation of an oxide film on the selective layer surface requires the use of an oxidizer.…”

Section: Introductionmentioning

confidence: 99%

The Effects of Friction and Temperature in the Chemical–Mechanical Planarization Process

et al. 2023

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Chemical–mechanical planarization (CMP) represents the preferred technology in which both chemical and mechanical interactions are combined to achieve global planarization/polishing of wafer surfaces (wafer patterns from metal with a selective layer, in this paper). CMP is a complex process of material removal process by friction, which interferes with numerous mechanical and chemical parameters. Compared with chemical parameters, mechanical parameters have a greater influence on the material removal rate (MRR). The mechanical parameters manifest by friction force (Ff) and heat generated by friction in the CMP process. The Ff can be estimated by its monitoring in the CMP process, and process temperature is obtained with help of an infrared rays (IR) sensor. Both the Ff and the MRR increase by introducing colloidal silica (SiO2) as an abrasive into the selective layer CMP slurry. The calculated wafer non-uniformity (WNU) was correlated with the friction coefficient (COF). The control of Ff and of the slurry stability is important to maintain a good quality of planarization with optimal results, because Ff participates in mechanical abrasion, and large Ff may generate defects on the wafer surface. Additionally, the temperature generated by the Ff increases as the SiO2 concentration increases. The MRR of the selective layer into the CMP slurry showed a non-linear (Prestonian) behavior, useful not only to improve the planarization level but to improve its non-uniformity due to the various pressure distributions. The evaluation of the Ff allowed the calculation of the friction energy (Ef) to highlight the chemical contribution in selective-layer CMP, from which it derived an empirical model for the material removal amount (MRA) and validated by the CMP results. With the addition of abrasive nanoparticles into the CMP slurry, their concentration increased and the MRA of the selective layer improved; Ff and MRR can be increased due to the number of chemisorbed active abrasive nanoparticles by the selective layer. Therefore, a single abrasive was considered to better understand the effect of SiO2 concentration as an abrasive and of the MRR features depending on abrasive nanoparticle concentration. This paper highlights the correlation between friction and temperature of the SiO2 slurry with CMP results, useful to examine the temperature distribution. All the MRRs depending on Ef after planarization with various SiO2 concentrations had a non-linear characteristic. The obtained results can help in developing a CMP process more effectively.

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“…At present, more than 2.5 million CMP polishing pads are expected to be used in the world every year [2], and this number is still growing rapidly. Therefore, research on polishing pad dressing and prolonging the service life of polishing pads will contribute to energy saving and emission reduction.The polishing pad plays an important role in storing chips and transporting the polishing liquid during the polishing process.…”

Section: Introductionmentioning

confidence: 99%

Characterization and dressing effect of CMP diamond disc conditioner with ordered abrasive distribution

Guo

Yang²,

Zhenhui³

et al. 2023

Preprint

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With the advent of the 5G information age, the production and processing of computer chips has attracted people's attention. In order to adapt to the rapid development in the field of chip manufacturing, high requirements are placed on chemical mechanical planarization (CMP). Among them, the porous structure on the surface of the polishing pad is easily blocked and loses its performance during the use of the polishing pad. Therefore, the use of diamond disc conditioner to dress the polishing pad in the CMP process is an indispensable part. In this paper, a new method of measuring the dressing disc is proposed, after the wax block is melted, it solidifies on the surface of the dressing disc to obtain the protrusion height of the grains, this method has more advantages than measuring with an optical microscope because of the error caused by the diffuse reflection of the microscope. For diamond conditioners used in the experiments, the dressing trajectory of abrasive grains is simulated, which is the basis on choosing the experimental method, and the material removal rate model of the polishing pad is established. In addition, the diamond conditioners with orderly distributed abrasive grains are used to dress the polishing pad after polishing silicon wafer two hours, the discs can remove the blocking material on the surface of the polishing pad after dressing 30 minutes, the dressing effect and efficiency of the diamond disc with grain size of 100µm is more obvious. The surface roughness and the liquid contact angle of the polishing pad before and after dressing are measured, after a period of conditioning, they can be restored to a state similar to that of the new polishing pad.

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Approaches to Sustainability in Chemical Mechanical Polishing (CMP): A Review

Cited by 67 publications

References 106 publications

Van der Waals Layer Transfer of 2D Materials for Monolithic 3D Electronic System Integration: Review and Outlook

Van der Waals Layer Transfer of 2D Materials for Monolithic 3D Electronic System Integration: Review and Outlook

The Effects of Friction and Temperature in the Chemical–Mechanical Planarization Process

Characterization and dressing effect of CMP diamond disc conditioner with ordered abrasive distribution

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