The effect of hydrogen peroxide on polishing removal rate in CMP with various abrasives

Manivannan, R.; Ramanathan, Surash

doi:10.1016/j.apsusc.2008.10.040

Cited by 50 publications

(28 citation statements)

References 23 publications

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“…4 and support the identification of the broad peak centered at ϳ300 nm with Ce 3+ and that at ϳ270 nm peak with Ce 4+ . Hence, the inescapable conclusion is that Ce 3+ adsorbs and binds to silica surfaces, 13,22,24 consistent with the role of Ce 3+ species that was proposed by Kelsall, 4 Wang et al, 6 and Manivannan and Ramanathan, 25 and there is no such interaction between Ce 4+ and silica surfaces.…”

Section: Absorbance (A U)mentioning

confidence: 65%

Role of Different Additives on Silicon Dioxide Film Removal Rate during Chemical Mechanical Polishing Using Ceria-Based Dispersions

Dandu

Peethala

Babu

2010

J. Electrochem. Soc.

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We discuss the role of several additives used with ceria-based dispersions to polish silicon dioxide films and investigate their interaction with both the abrasives and silicon dioxide films using several techniques. Our results suggest that the amount of adsorption of the additives on the ceria abrasives controls the reactivity of the abrasives with the silicon dioxide film and, hence, the silicon dioxide removal rates ͑RRs͒. With several additives, the complete blockage of the reactive species and the reduction of the oxide RR to Ͻ2 nm/min occur only when the amount of the additive adsorbed has reached a limiting value.

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Section: Absorbance (A U)mentioning

confidence: 65%

Role of Different Additives on Silicon Dioxide Film Removal Rate during Chemical Mechanical Polishing Using Ceria-Based Dispersions

Dandu

Peethala

Babu

2010

J. Electrochem. Soc.

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“…These results are in accordance with earlier data [4][5][6][7] and support the more complicated nitride polishing mechanism in which the nitride is hydrolyzed to suboxide and then this suboxide is removed during polishing. 11,12 Additional factors such as H-bonding, hydrophobic/ hydrophilic interaction, basicity, and site blocking can also affect the polishing process. [5][6][7] Perhaps this explains why a simple correlation between the structure and even the COF value on one hand and the RR on the other is not as good as that for the oxide removal.…”

Section: Resultsmentioning

confidence: 99%

Complexing Between Additives and Ceria Abrasives Used for Polishing Silicon Dioxide and Silicon Nitride Films

Wang

Liao

Zhang

et al. 2011

Electrochem. Solid-State Lett.

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Various water soluble organic additives were used in ceria-based slurries to control both the silicon oxide and silicon nitride film removal rates. Our polish results and zeta potential data suggest that the additives with ␤-diketonatelike structures can inhibit both oxide and nitride removal rates. We propose possible complexing between the additives and the ceria abrasives might be responsible for this removal rate inhibition.Since 0.25 m technology node and beyond, shallow trench isolation ͑STI͒ has replaced traditional LOCOS ͑local oxidation of silicon͒ to provide better device isolation. 1 In a typical STI process, silicon nitride and thermal oxide are sequentially deposited on Si and trenches are created between each active area by etching, and subsequently silicon dioxide ͑SiO 2 ͒ is deposited. Then the excess SiO 2 layer present on the active area is removed by chemical mechanical polishing ͑CMP͒ stopping on the silicon nitride, which acts as a protective layer on the active area. In the last step, the nitride film is removed by wet etching or polishing, leaving the trench-filled oxide to isolate the devices. 2,3 During the STI fabrication process, CMP is a key step which requires a complete removal of oxide and a minimal loss of the underlying nitride. Ceria-based slurries can preferentially remove the overburden oxide layer with minimal polishing of nitride in the presence of specific additives, which fits well with the requirements of the STI CMP process and has aroused much interest in recent years. 1,2Earlier, Ramanathan et al. 4 identified several ceria-based slurries which suppress the silicon nitride removal rates ͑RRs͒ without affecting silicon dioxide RRs using different acidic amino acids such as proline, glycine, glutamic acid, etc., as additives. Later, America and Babu 5 identified that proline suppresses the silicon nitride RRs more effectively when compared to the other amino acids at pH ϳ 9.7. They proposed that proline binds to the silicon nitride surface through a combination of hydrogen and bidentate bonding, and hinders its hydrolysis. In addition, Dandu et al. 6 recently showed that this proline film on the silicon nitride surface survives even after polishing for Ͼ5 min.Carter and Johns 7 reported that oxide to nitride removal selectivity could be varied by 3 orders of magnitude using different organic amines, acids, and amino acids as additives in ceria-based slurries at pH 5. They proposed that the nitride polishing could be influenced by the additives' basicity through a site-blocking mechanism, while the oxide RRs would be decreased by the additives which are likely to adsorb on either the oxide or the ceria surface by preventing direct Si-O − interactions with ceria. Later, Dandu et al. 6 observed that the silicon nitride RRs can also be suppressed using different cyclic amines as additives in ceria-based dispersions in the entire pH range 2-12. They proposed that these amines adsorb on the silicon nitride surface through H-bonding and, hence, prevent hydrolysis. Kim et al. 8 ...

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“…In this pH range, the oxide and nitride RRs decreased with an increase in DOC. In another report, Manivannan and Ramanathan 77 showed that the addition of H 2 O 2 to ceria slurries caused a drastic reduction in oxide and nitride RRs in the pH range of 7-10. Both these sets of results could be explained if Ce 3+ is the active site, which would be converted to Ce 4+ (assumed to be less active) at higher DOC or by the addition of H 2 O 2 .…”

Section: Ecs Journal Of Solid State Science and Technology 4 (11) P5mentioning

confidence: 99%

Shallow Trench Isolation Chemical Mechanical Planarization: A Review

Ramanathan

Dandu

Babu

2015

ECS J. Solid State Sci. Technol.

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Electrical isolation of the billion or so active components in each integrated device is achieved using shallow trench isolation (STI) which requires chemical mechanical planarization (CMP) involving silicon dioxide removal at a high rate and stopping on an underlying silicon nitride film. Several colloidal slurries with various additives can yield the desired high rate selectivity between the oxide and nitride films during CMP while maintaining an acceptably low nitride rate. Here, many of such high selectivity STI CMP slurries described in the literature are reviewed along with the characteristics of the colloidal dispersions like the abrasives, additives, the interactions between them and with the films being planarized and the associated pH range in which the high selectivity is observed. The mechanisms proposed to explain the high reactivity of ceria with oxide, the role of additives in suppressing the nitride removal rate and resulting high selectivity are discussed. Reduction of a multitude of defects in post-CMP processed STI structures still remains an important challenge, especially as the feature sizes continue to shrink. Chemical mechanical planarization (CMP) is one of the important enabling processes in facilitating multilevel metallization (in some cases reaching up to 14 levels) and incorporation of novel gate and channel materials at the component level in modern semiconductor device manufacturing where its use has become widespread and ubiquitous.1-6 Here, we review recent advances and remaining challenges in one specific application of CMP, the shallow trench isolation (STI) process. STI is a method of electrically isolating active areas using trenches created in the Si substrate around the active elements and filling it with an insulating dielectric, such as silicon dioxide or silicon oxy-nitride or silicon carbonitride.7-11 Process details of the STI structures are available in numerous publications. There are a multitude of techniques available for oxide deposition and even though the resulting oxides have very different properties, for simplicity we do not distinguish between them in this review. For completeness and ease of reference, a schematic representation of the STI process is given in Figure 1. While the trenches are being filled, silicon dioxide also deposits over unwanted areas on the entire wafer (since selective deposition in trenches only is not possible) creating an uneven topography. The excess and unwanted oxide has to be completely removed and CMP has proven to be the only viable and robust global and local planarization capable process technology.Here, as shown in Figure 1, presence of a very thin silicon nitride stop layer (deposited on another thin pad oxide layer to control film stress) is an essential and integral part of the process. This nitride stop layer prevents any damage during planarization to the all-important epitaxially grown surface underneath and is itself removed by a wet etch process subsequent to the overburden oxide removal. Since the integrity of the...

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The effect of hydrogen peroxide on polishing removal rate in CMP with various abrasives

Cited by 50 publications

References 23 publications

Role of Different Additives on Silicon Dioxide Film Removal Rate during Chemical Mechanical Polishing Using Ceria-Based Dispersions

Role of Different Additives on Silicon Dioxide Film Removal Rate during Chemical Mechanical Polishing Using Ceria-Based Dispersions

Complexing Between Additives and Ceria Abrasives Used for Polishing Silicon Dioxide and Silicon Nitride Films

Shallow Trench Isolation Chemical Mechanical Planarization: A Review

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