Effect of pad surface roughness on material removal rate in chemical mechanical polishing using ultrafine colloidal ceria slurry

Han, Song; Kim, Hee Jin; Hong, Myung Ki; Kwon, Byoung Ho; Lee, Kuntack; Ko, YoungSun

doi:10.1007/s13391-012-2144-5

Cited by 17 publications

(10 citation statements)

References 17 publications

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“…In the case of the ceriabased slurry, the material removal rate increases as the pad roughness decreases by reduced pad conditioning. 11,12 In the case of a silica-based slurry, when the pad roughness decreases, the material removal rate decreases because of pad glazing, which indicates the deformation of asperities. 13 These relationships mean that for the Table IV.…”

Section: Resultsmentioning

confidence: 99%

Investigations of the Pad Trajectory Effect on the Asymmetric Profile and Arc-Shaped Scratches in Chemical Mechanical Polishing

Hwang

Seo

Kwon

et al. 2021

ECS J. Solid State Sci. Technol.

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Research was conducted on the trajectories formed by fixed positions on the pad and how these trajectories affect the asymmetric profile and arc-shaped scratches in chemical mechanical polishing (CMP). Also investigated was whether the local glazing of the pad surface affects the asymmetric profile using the Si 3 N 4 film and ceria slurry, whether the end point detection (EPD) window on the pad could cause a very fine asymmetry profile according to the process conditions using the poly-Si film and silica-based slurry, and the arc-shaped scratches generated in W and Cu CMP were compared with the calculated trajectories. Based on these studies, it was confirmed that the With-In-Wafer (WiW) asymmetry profile can appear and the WiW range can be rapidly changed up to 500% depending on the polish time and the speed of platen and wafer carrier head. It can further be deduced that the repetitive arcshaped macro scratching phenomenon is caused by a fixed scratch source on the pad. To solve this problem, we suggest the prevention of abrasive aggregation and optimization of in situ conditioning. By comparing the repetitive scratch shape and the calculated trajectory, it was possible to judge the scratches that occurred.

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Section: Resultsmentioning

confidence: 99%

Investigations of the Pad Trajectory Effect on the Asymmetric Profile and Arc-Shaped Scratches in Chemical Mechanical Polishing

Hwang

Seo

Kwon

et al. 2021

ECS J. Solid State Sci. Technol.

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“…Transmission electron microscope image of calcined ceria abrasive and nano-sized abrasive is compared in Figure 14 [44]. Single abrasive size becomes as small as 5 nm.…”

Section: Advanced Abrasives For Future Cmp Applicationsmentioning

confidence: 99%

“…However, CMP mechanism of nano-sized cerium hydroxide abrasive is not clearly understood yet. Han et al reported polishing pad surface roughness control is critical to maintain removal rate stability with nano-sized cerium hydroxide abrasive [44]. Kim proposed particle coverage model on the wafer as material removal mechanism with nano-sized cerium hydroxide abrasive [43].…”

Section: Advanced Abrasives For Future Cmp Applicationsmentioning

confidence: 99%

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Abrasive for Chemical Mechanical Polishing

Kim¹

2018

Abrasive Technology - Characteristics and Applications

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Chemical mechanical polishing (CMP) is one of the most essential processes in semiconductor manufacturing. Its importance becomes highly underscored at the advanced device toward sub 14 nm scaling. The fundamental mechanism of CMP is to create soften surface layer by chemical reaction and then, mechanical force by abrasive particles remove soften layer. The role of CMP is not only material removal, but also planarization, surface smoothening, uniformity control, defect reduction and more. Moreover, semiconductor yield enhancement is sensitively influenced by CMP processing. Surface scratching, which is generated by CMP in nature, is considered as 'killer defect' in semiconductor manufacturing. Hence, to achieve proper CMP performance without surface scratching, understanding and development of abrasive particles are crucially important. In this chapter, CMP fundamentals, applications and challenges associated with abrasive particle technology including synthesis (up to nanoparticle scale), tribochemical reaction, abrasive surface zeta potential behavior, particle size and its distribution will be discussed.

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“…The rate enhancement suggests that the CVD conditioner may have reduced the pad surface roguhness to increase the effective contact area between SiO x wafer surface and ceria abrasives through pad asperities, leading to higher material removal through accelerated chemical reactions. 19,20 However, the use of CVD pad conditioner in conjunction with ceria slurry leads to an increase in ceria abrasive loading on wafer surface as shown in Fig. 6.…”

Section: Effects Of Pad Conditioning and Cvd Conditionermentioning

confidence: 99%

Post Cleaning for FEOL CMP with Silica and Ceria Slurries

Tseng

McCormack

et al. 2017

ECS J. Solid State Sci. Technol.

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Post cleaning experiments for front end of the line (FEOL) CMP with silica and ceria slurries are carried out on commercial polishers with 300 mm oxide, nitride, and integrated shallow trench isolation (STI) wafers. Considering the charge attraction or repulsion between particles and wafer surface, both acidic and basic clean chemicals are applied at different stages in the post CMP process sequence. Diluted hydrogen peroxide in a non-contact megasonic cleaner is used to remove ceria abrasive particles and polish residues with high efficiency. On-platen buff clean with or without pad conditioning can make an impact on the post CMP cleaning performance. Post CMP cleaning splits are executed in order to evaluate the effectiveness of each of the process steps and their roles in the overall cleaning performance. Silica-based slurries are usually adopted for bulk oxide polish while ceria-based slurries are more suited for the final "buff" polish where high selectivity is required. The ever stringent requirements for scratch reduction lead to the trend of adopting nano-sized (< 60 nm) abrasive particles in all types of CMP slurries. However, the higher surface charges per area of these nanoparticles and the resulting stronger adhesion force between them and wafer surface necessitates the modification of the chemistry and optimization of post CMP (pCMP) cleaning process to meet the low defect requirement.Between silica and ceria abrasive particles, the latter are heavier in weight and irregular in shape (as opposed to circular like silica), and hence may present more challenges for pCMP cleaning from weight and geometry point of view. However, atomic force microscope (AFM) measurement suggests that the adhesion force of irregular ceria is much lower than that of spherical silica on the surface of TEOS oxide, SiN x , and poly-Si in both acidic and basic pH regimes.1 Unlike silica, ceria exhibit redox reactions on SiO x surface, which should be taken into account when selecting the chemicals for pCMP cleaning. Meanwhile, besides silica and ceria abrasive particles, a robust FEOL pCMP clean process need to remove organic additives from slurry itself; by-products or polish residues (PR) such as SiO x , SiN x , and poly-Si from the wafer; and debris from CMP consumables such as pad (PU, polyurethane), carrier (stainless steel), retaining ring (e.g., polyether ether ketone, PEEK), and roller brush (polyvinyl alcohol, PVA).The selection of proper chemicals is often the first step toward pCMP cleaning. However, design of cleaning sequence, exploitation of the tool hardware, and optimization of process parameters are equally critical to achieve maximum cleaning efficiency.2 During the final ("buff") polish step, for example, the use of hard vs. soft pads, in-situ vs. ex-situ conditioning, and pad rinse with DIW vs. clean chemical can all modulate defect generation to various degrees, and hence affect the overall post cleaning performance. In the post CMP clean module, cleaning with or without mechanical contact, brush or "penci...

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Effect of pad surface roughness on material removal rate in chemical mechanical polishing using ultrafine colloidal ceria slurry

Cited by 17 publications

References 17 publications

Investigations of the Pad Trajectory Effect on the Asymmetric Profile and Arc-Shaped Scratches in Chemical Mechanical Polishing

Investigations of the Pad Trajectory Effect on the Asymmetric Profile and Arc-Shaped Scratches in Chemical Mechanical Polishing

Abrasive for Chemical Mechanical Polishing

Post Cleaning for FEOL CMP with Silica and Ceria Slurries

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