bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Effects of Weak Viscoelasticity on Enhanced Particle Removal for CMP
Authors: Cashen Ryan , Ozbek Sebnem , Conradt Jason , Basim Gul Bahar , Walker Travis 
Published: July 2021

Highly elastic solutions have been shown to increase particulate removal from silicon wafers, indicating the possibility for reduced reliance upon hazardous chemicals and expensive technologies during post-CMP cleaning processes. We explored the onset of this enhanced removal using micron-sized silica particles in rinsing and siphoning experiments with polymer fluids of high molecular weights that ranged from dilute to entangled concentrations. Increases in particle removal with less than 100 ppm of polymer were observed using both methods, with 10% increased removal observed in the rinsing experiment and 4% increased removal in the siphoning experiment relative to water. Further increases in polymer concentration increased removal significantly, as the solutions entered the semidilute regime. Highly concentrated solutions showed “streaking” patterns, consistent with the viscoelastic nature of the solution. Additionally, we examined particle removal as a spatially dependent parameter in siphoning experiments, showing a plateau of significant removal near the siphon with a sharp decay to a constant value at distances farther away from the siphon.
Rheological characterization of the siphoning and rinsing polymer solutions was used to explore relationships between observed removal and solution properties. Increases in particle removal with solutions having nearly indistinguishable shear rheology and immeasurable extensional character were observed, indicating the need for more precise methods for extensional characterization of dilute polymer solutions. The application of polymer solutions to particle-removal processes has the potential to simplify post-CMP cleaning and reduce the environmental impact that is associated with present particle-removal chemistries.

Figure 1: Removal profile of micron-sized silica particles on glass slides that were subjected to fluid siphoning. Crosshairs indicate the point on the glass slide directly under siphon. Siphoning solutions consisted of water (a), and poly (ethylene oxide) at concentrations of 50, 100, 500, 1000, and 5000 parts-per-million (b-f, respectively). Particulate area was determined by the total pixel count of silica particles in each image. Removal profiles for dilute solutions (a-c) show similar spatial dependence with mild increases in average removal. Removal profiles for semidilute solutions (d-e) show clear radial dependence while the concentrated solution showed behavior associated with significant elastic character.

Figure 1
Observation of Polymer Additive Absorption on Substrates for STI CMP Slurries
Authors: Nomura Satoyuki , Lee Sangchul , Yanagisawa Masahiro , Homma Takayuki 
Published: July 2021

High SiO2 to SiN removal rate selectivity and SiN removal rate suppression are indispensable for the shallow trench isolation (STI) CMP slurry and those characteristics are achieved by the polymer additives such as poly-acrylic acid (PAA). Recently, it is reported that the polymers containing hydrophobic and hydrophilic moieties show high selectivity and SiN removal rate suppression [1, 2]. For further improvement of these characteristics, it is important to clarify the mechanisms of the effects of the polymer additives. Several studies have reported that polymer additives preferentially adsorbs on the SiN film resulting high rate selectivity [2, 3]. However, evaluation of adsorption properties of the polymer additives are limited to thermal or electrochemical analysis and few studies have been reported on the direct observation of adsorbed polymers on the SiO2 and SiN surfaces. In this study, we have investigated adsorption properties of the polymer additives by using surface enhanced Raman scattering (SERS) suitable for analysis of trace organic substance on surface in water.
Figure 1 schematically illustrates the measurements of SERS spectra. The SiN/SiO2=30/70 m patterned wafer chip with 1% polymer solution is putted on the quartz glass with Ag nanoparticles, resulting high Raman scattering intensity. Figure 2 show the spectra measured on the SiO2 and SiN films in PAA solution. The peak of CH stretching mode of the PAA polymer chain was observed at approximately 2935 cm-1 on the SiO2 and SiN. This result implies that the polymer is adsorbed both on the SiO2 and SiN. Meanwhile, the case in the polymer containing hydrophobic moiety, the peak attributed to the hydrophobic group is observed at approximately 1000 cm-1. Its intensity is stronger on the SiO2 than SiN, indicating the preferential adsorption of polymer on the SiO2 surface.
The ratio of peak intensity of polymer on the SiN to SiO2 (SiN/SiO2) for PAA (0.26) is higher than the polymer containing hydrophobic moiety (0.03), implying that the adsorption of polymer with hydrophobic moiety to the SiN film is lower than PAA. This suggests that the nitride removal suppression effect is not caused by the adsorption of the polymer on the SiN surface. The influence of other components, such as abrasive, dispersant, pH adjuster is under investigation.
[1] T. Otsuki, US Pat. 2019/0136089 (2019).
[2] N. K. Penta et. al, Appl. Surf. Sci., 283, 986(2013)
[3] S. Kim et. al., J. Colloid Interface Sci., 319, 48 (2008).

Figure 1
Applicate Tangential Flow Filtration System to Improve Post CMP-Cleaning Performance
Authors: Lee Jaewon , Seo Hyeonmin , Park Sang-hyeon , Hong Seokjun , Kim Taesung 
Published: July 2021

Chemical mechanical polishing (CMP) is one of the important process steps in semiconductor manufacturing. Several types of abrasives are used in the CMP process, among these, ceria slurry is commonly used through its excellent polishing performance in terms of oxide MRR. However, ceria particles remain on the wafer surface after polishing process as contaminants, and small ceria particles are difficult to remove from wafer surface [1].
In this respect, we focused to treat small ceria particles that interfere with the cleaning process and we applicate the tangential flow filtration (TFF) system before the CMP process. TFF system is a system for separation of particles by Brownian motion, shear-induced diffusion and the mechanism shown in Fig. In this experiment, separation of small ceria particles successfully and it was evaluated by scanning mobility particle sizer (SMPS) analysis. Furthermore, TFF system did not affect the slurry properties of particle mean diameter, pH value, and zeta potential.
In this study, concentration of ceria particles on the wafer surface after CMP process were evaluated by ICP-MS analysis. We calculated the cleaning efficiency with and without TFF separation system. As a result, cleaning efficiency was improved by using TFF system. In addition, the removal rate of SiO2 was almost maintained and the deviation decreased.

References

[1] J. Seo, A. Gowda and S. Babu, ECS Journal of Solid State Science and Technology, 7, P243 (2018).

Figure 1
Prediction of Pad Profile with Pressure Distribution on Diamond Disk at Pad Edge
Authors: KIM Eungchul , Kim Taesung 
Published: July 2021

The conditioning process in chemical mechanical polishing (CMP) has an important role to maintain the uniform CMP performance using the diamond attached on a rotating disk. This process maintains the uniform surface roughness and profile of the pad, which results in the steady material removal rate (MRR) and within wafer non-uniformity (WIWNU). The pad uniformity varies greatly by mechanical action in the conditioning process, which is controlled by three mechanical actions: pad/conditioner rotation and sweeping motion of the conditioner arm.
When diamonds scratch on a pad, it is possible to assume that the pressure distribution of a diamond disk is uniform when the disk fully contacts the pad, however, the pressure distribution on a diamond disk is not uniform anymore in a condition with the disk getting off the pad edge. For this reason, when a disk is set to sweep over the pad edge, there were problems with a hump area at the near edge of the pad. This hump area can affect the WIWNU and disturb the elimination of waste matter from the results of CMP.
In this study, the process of conditioning in CMP was analyzed topologically and the program was developed through it. First, the movement of diamond grits calculated and the wear amount was obtained by accumulating the number of points in the mesh containing the coordinates of the diamonds moving at a specific time or distance. Second, indentation depth was analyzed according to the structural properties of a disk and the wear depth of the pad was analyzed in uniform-pressure condition. Third, the pressure distribution on a disk at the pad edge was analyzed as shown in Fig. 1 and adapted to an algorithm predicting pad profile. Finally, we got a simulated pad profile by the algorithm and the results were compared with experimental results in the same condition as shown in Fig. 2.
SEMI Standards for Consumables for Chemical Mechanical Planarization (CMP)
Authors: Tregub Alex , Nguyen Laura 
Published: July 2021

IC manufacturing is a sophisticated multistep process where parameters need to be monitored and controlled very tightly. Chemical-mechanical polishing (CMP) is an important step in IC manufacturing that is required to achieve global and local planarity for subsequent lithography processes. CMP has been one of the fastest-growing segments of the semiconductor industry for the past 20 years.
The CMP process is highly critical for achieving sustainable yields in IC manufacturing. This area is also one of the most difficult to control. Quality issues in the CMP process are extremely expensive and can have a significant impact to device yields and reliability. It is known that CMP consumables, such as CMP pads, CMP slurries, and CMP conditioning disks are critical to achieve the target performance in IC manufacturing processes. As such, reducing the variations in CMP consumables properties through standardized metrology tools and processes has become a high priority for advanced IC manufacturing nodes.
In this presentation we will focus on measuring and reporting critical parameters for such critical and widely used consumables in the CMP industry, as CMP pads ([Ref. 1-4]), retainer rings, and conditioning disks.
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References
1. Jianfeng Luo, David A. Dornfeld: IEEE TRANSACTIONS ON SEMICONDUCTOR MANUFACTURING, VOL. 14, NO. 2, MAY 2001
2. SEMI C100 - Guide for Reporting Chemical Mechanical Planarization (CMP) Polishing Pads Hardness Usedpublished by SEMI Standards (https://store-us.semi.org/products/c10000-semi-c100-guide-for-reportingchemical-mechanical-planarization-cmp-polishing-pads-hardness-used-in-semiconductor-
3. A. Tregub, G. Ng, J. Sorooshian and M. Moinpour, "Thermoanalytical characterization of thermoset
Effect of Retainer Ring Pressure in Ceria Based CMP
Authors: Oh Seungjujn , Kwak Donggeon , Kim Juhwan , Kim Taesung 
Published: July 2021

Consumable of Chemical mechanical polishing (CMP) process for global planarization can be divided by pad, conditioner, and slurry. Wafer is applied to pressure on the pad with Slurry. Among the abrasives contained the slurry, although ceria has a low concentration, the removal rate is higher than the silica on inter-layer dielectric (ILD)/inter-metal dielectric (IMD) CMP process. Removal rate (RR) increased by Preston’s equation in proportion to the pressure and rpm (RR=KPV). Where K is a Preston’s constant, P is the main pressure, and V is the relative velocity. Yield improvement method in the semiconductor is a large uniform area after CMP process. In other words, wafer edge area should be minimized. It is important to control uniform pressure distribution. Head structure can be divided by main pressure for removal and retainer ring pressure for prevention out of course. In this research, pressure distribution is demonstrated by controlling the different pressure wafer pressure and retainer ring in a single pressure structure. Removal rate changed by different pressure due to pad deformation. Relative pressure difference changed from 150 to 30 g/cm2 to demonstrate for the reason. In case of the low pressure (1, 2psi), the smaller relative pressure difference increases the uniformity, but the removal rate is decreased. In the high pressure (3, 4 psi), the removal rate and uniformity are not big changes according to relative pressure difference. But parameters of temperature and coefficient of friction are not same. This research investigated the mechanism of how to affect the ceria in ILD/IMD CMP through each parameter.
Figure 1. Removal rate according to relative pressure difference of retainer ring, (a) low pressure, and (b) high pressure.

Figure 1
(Invited) Extend Calendar Life of Si Based Li-Ion Batteries
Authors: Zhang Ji-Guang , Yi Ran , Li Qiuyan , Chae Sujong , Cao Xia , Li Xiaolin , Xu Wu 
Published: July 2021

Although significant progress has been made in increasing the specific energy and cycle life of silicon (Si) based Li-ion batteries (Si-LIBs), calendar life of these batteries is still less than two years, which is far less than the 10 year life-time required for electrical vehicle applications.1 Graphite anodes undergo only ~10% volume change during cycling, so SEI formed during the initial process does not experience significant mechanical stress during the subsequent cycles. However, the SEI layer formed on Si anodes experiences tremendous mechanical stress during repeated cycles. Most SEI layers formed on the Si surface in conventional electrolytes break down, exposing fresh, lithiated Si or SiO to electrolyte. Thus, significant Si corrosion and electrolyte consumption continuously occur during battery storage, especially in the fully lithiated conditions and elevated temperatures required for the accelerated calendar life test.2 As a result, the impedance of the Si anode will increase much faster than a graphite anode and shorten its calendar life, as observed in nearly all Si-LIBs. In this work, we will report the results of our recent investigation on the fundamental mechanism behind the limited calendar life of Si-LIBs. Several approaches that alleviated degradation of SEI layer and increasing cycle life of Si-LIBs will be discussed, including the nanostructured Si designs that can minimize the external size expansion, minimized particle surface area, and formation of stable SEI layers by localized high concentration electrolyte tailored for Si anode. The combination of these methods can largely extend the calendar life of Si-LIBs and accelerate the application of these batteries for large-scale electrical vehicles and consumer electronics applications.
References:

Brain Cuttingham, Presentation in 2020 AMR review meeting. https://www.energy.gov/eere/vehicles/2020-vehicle-technologies-office-amr-presentations-program
2020.

Idaho-National-Laboratory, United States Advanced Battery Consortium Battery Test Manual For Electric Vehicles. http://www.uscar.org/commands/files_download.php?files_id=517
2020.
Glyoxales As New Electrolytes for Si/Graphite-Anodes in Lithium-Ion Batteries: Analysis of the Solid-Electrolyte Interphase
Authors: Gehrlein Lydia , Leibing Christian , Pfeifer Kristina , Balducci Andrea , Maibach Julia 
Published: July 2021

Electrolytes play a crucial role when considering the safety aspects of a Lithium-ion battery. Most commonly, linear and cyclic carbonate-based electrolytes are used commercially. Their advantage lies in the combination of low viscosity and high dielectric constant. However, they display various safety issues such as a limited temperature stability window and high toxicity of the used Li-salt[1]. A new promising alternative are glyoxal based electrolytes using solvents such as tetraethoxy glyoxal (TEG) and tetramethoxy glyoxal (TMG)[2]. Both solvents display low viscosity, low toxicity, high flash points, and very low melting points. Previous works have shown that TEG containing electrolytes display good electrochemical performance in graphite and lithium iron phosphate half-cells as well as in NMC||graphite full-cells[2],[3],[4].
With this work, we report the first use of TEG and TMG based electrolytes for silicon-graphite anodes. Our results show that in terms of capacity retention the TEG-based electrolyte outperforms TMG as well as the 2 reference electrolytes, namely LP30 (LiPF6 in EC/DMC) and L-E/D (LiTFSI-EC/DMC) (see figure). In this presentation, we focus on is the analysis of the solid electrolyte interphase (SEI) formed by these electrolytes. The interphase was studied by photoelectron spectroscopy (XPS) at specific potentials during SEI formation in the first cycle as well as after 100 cycles. We correlate SEI composition and thickness with the electrochemical performance depending on electrolyte composition, suggesting that TEG shows a thinner yet more stable SEI.

References

[1] S. Nowak, M. Winter, J. Electrochem. Soc., 2015, 162 (14) A2500-A2508.
[2] L. H. Hess, A. Balducci, ChemSusChem, 2018, 11, 1919-1920.
[3] L. H. Hess, S. Wankmüller, L. Köps, A. Bothe, A. Balducci, Batteries & Supercaps, 2019, 2, 1-7.
[4] J. Atik, S. Röser, R. Wagner, D. Berghus, M. Winter, I. Cekic-Laskovic, J. Electrochem. Soc., 2020, 167, 040509.

Figure 1
Revealing Ageing Mechanisms of Ni-Rich NCA in State-of-the-Art Commercial High-Energy Li-Ion Cells
Authors: Mikheenkova Anastasiia , Smith Alexander James , Roy Chowdhury Niladri , Thiringer Torbjörn , Wreland Lindström Rakel , Pay Gómez Cesar , Lacey Matthew , Berg Erik J. 
Published: July 2021

Ni-rich Li[NixCoyAlz]O2 (NCA) positive electrode materials are today found in the state-of-the-art high-energy Li-ion batteries [1]. Considering the high production cost of these batteries combined with the scarcity and environmental impact of the included transition metals, large benefits would be gained by prolonging the lifetime of the Li-ion cells. Although NCAs are the key to a high energy density, they are generally believed to be the main culprit behind the failure of the cell [2]. The NCAs are subjected to adverse structural phase transformation and display increased surface reactivity towards the electrolyte upon electrochemical charging [3]. Particle cracking, surface reconstruction and associated electrolyte decomposition are well-known processes leading to both Li+ inventory loss and increased cell impedance. Yet, several aspects governing these underlying ageing mechanisms remain to be explained, particularly for Ni-rich NCAs contained in state-of-the-art commercial Li-ion cells today.
Herein we present a combined structural and electrochemical study based on detailed X-ray diffraction analysis, electron microscopy, and intermittent current interruption cycling. The extent and impact of the various ageing mechanisms at each stage of battery life will be assessed and discussed [4].

Reference
s
:

[1] Yuliya Preger et al 2020 J. Electrochem. Soc. 167 120532
[2] A. Manthiram, B. Song, and W. Li, Energy Storage Mater. 6 (2017) pp. 125–139.
[3] E. Flores, P. Novák, U. Aschauer, and E. J. Berg, Chem. Mater. 2020, 32, 1, 186–194
[4] Mikheenkova et al. In preparation.
Effect of Processing Routes on Structural and Electrical Properties of High Energy-Density Oxide Cathode Materials
Authors: Fung Kuan-Zong , Tsai Shu-Yi , Kenneth Fung , Chang Chia-Chin 
Published: July 2021

Cathode materials with high energy density for Li ion batteries have received great attention due to the high demand in transportation applications. Although several crystal structures have been demonstrated and shown reversible capabilities during lithiation/delithiation processes in cathode of Li ion batteries; oxides with layered/spinel structure still remain the ones that provide higher energy densities.
However, higher energy density means the creation of more ionic/electronic defects in both cation and/or anion sublattices of layered/spinel structures. Higher defect concentration in either cation or anion sublattices tend to destabilize its crystal structure. As a result, the phase change is frequently observed in repeatedly cycled cathode. Furthermore, the phase-changing cathode tends to show the capacity fading after cycling tests. Based on defect consideration, the stability of highly defective materials may be enhanced by using dopant and/or better processing routes. In this study, the electrical/electrochemical/structural properties of oxide cathodes will be investigated.
First, the electrical measurement of spinel/layered oxides are conducted using sintered disc. Assembled cells using above-mentioned cathode and Li anode with desired liquid electrolyte will be tested and cycled. XPS, SEM and XRD analyses will be conducted on as-assembled as well as cycled cells. The analyzing results will be illustrated based on the processing parameters and defect chemistry of doping ions and the accompanying defects created.