Abrasive and additive interactions in high selectivity STI CMP slurries

Praveen, B.; Manivannan, R.; Umashankar, T. D.; Cho, Byoung-Jun; Park, Jin-Goo; Ramanathan, Surash

doi:10.1016/j.mee.2013.10.004

Cited by 28 publications

(22 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The difference between these results suggests that the synthesis method and/or the purity of the abrasives may have played a role. Praveen et al 71 also showed that the calcination temperature of synthesized ceria particles and the associated crystallite size impact P5034…”

Section: Characteristics Of Ceria Abrasivesmentioning

confidence: 99%

“…Not only the method of preparation but also the associated impurities in the ceria particles seem to play a role on STI performance. For example, Praveen et al 71 compared the selectivity obtained in slurries containing either L-proline or L-glutamic acid with ceria abrasives from three different sources: Sigma Aldrich (ceria-SA), Sodiff, Korea (ceria-S) and ceria prepared by calcination of Ce 2 (CO 3 ) 3 followed by milling (ceria-CM). The ceria-SA and ceria-S abrasives, but not ceria-CM, were found to contain La as an impurity.…”

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

confidence: 99%

See 1 more Smart Citation

Shallow Trench Isolation Chemical Mechanical Planarization: A Review

Ramanathan

Dandu

Babu

2015

ECS J. Solid State Sci. Technol.

View full text Add to dashboard Cite

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...

show abstract

Section: Characteristics Of Ceria Abrasivesmentioning

confidence: 99%

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.

View full text Add to dashboard Cite

show abstract

“…The nitride removal was completely suppressed in ceria-SG slurries while a polish rate of 37 nm/min was observed in ceria-SGL slurries. In some of the earlier reports [3,7], L-proline was shown to suppress nitride removal, but there were also other reports [12,17] indicating that it did not always suppress silicon nitride polishing. While the purity of the ceria employed in one of the reports [12] is not known, commercial ceria containing La impurity was employed in the second study [17].…”

Section: Polishing Resultsmentioning

confidence: 91%

“…3. There are no visible peaks present in the spectrum of ceria-SG particles, where as two clear distinct peaks are present in the spectrum of ceria-SGL particles at binding energy values of 836 eV and 854 eV indicating the presence of La [17,25]. Thus XPS analyses clearly identify the presence of La peaks in ceria-SGL particles and also show that the fraction of Ce 3 þ in the abrasive surface is slightly higher in case of ceria-SGL.…”

Section: Size and Composition Analysismentioning

confidence: 78%

“…They also reported that weak hydrogen bonds were formed between silicon dioxide and amino acids, resulting in enhanced oxide polishing. However, later studies showed that when nitride wafers were polished using slurries containing different ceria abrasives but with the same additives, the polishing results were different [17]. Glutamic acid yielded high selectivity regardless of the type of abrasive used for polishing.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation