Superfilling Evolution in Cu Electrodeposition

Kim, Soo-Kil; Kim, Jae Jeong

doi:10.1149/1.1777552

Cited by 69 publications

(93 citation statements)

References 15 publications

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“…This means that 2 equivalents of MPS was more effective than 1 equivalent of SPS in accelerating Cu reduction on the flat electrode, as reported by Tan et al and Moffat et al who observed the stronger acceleration effect of MPS than SPS using chronoamperometry experiments. 46,47 Despite the superfilling-incapability of MPS, its electrochemical acceleration effect, as shown in Figure 2 and the literature, 22,23,[44][45][46] might lead to significant error in the results of conventional MLAT-CVS analysis since the electrochemical responses of SPS and MPS are not distinguishable in the conventional MLAT-CVS. (Note that conventional MLAT-CVS provides only a stripping charge value, regardless of where the increased stripping charges originate-from either MPS or SPS).…”

Section: ) Concentration Of Total Accelerating Compounds (C T )mentioning

confidence: 99%

“…Similar results were reported by Kim et al showing that MPS itself is unable to induce bottom-up filling, whereas its dimerized form, SPS, enabled superfilling. 22 One notable point is the adverse effect of MPS on the filling capability. Figures 3a and 3d show that in the absence of MPS in the plating solution, an SPS concentration within the range of 25-50 μM is sufficient to induce superfilling.…”

Section: ) Concentration Of Total Accelerating Compounds (C T )mentioning

confidence: 99%

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High Accuracy Concentration Analysis of Accelerator Components in Acidic Cu Superfilling Bath

Choe

Kim

et al. 2015

J. Electrochem. Soc.

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We have devised a modified cyclic voltammetry stripping (CVS) method to measure the concentrations of bis-(sulfopropyl) disulfide (SPS) and 3-mercapto-1-propane sulfonate (MPS) in Cu plating solutions. Though MPS, a breakdown product of SPS, enhances the Cu deposition rate on flat electrodes, it is not a superfilling-capable accelerator for the damascene structure, unlike SPS. Therefore, accurate measurement of SPS in damascene Cu plating baths is important. However, enhancement of the Cu deposition rate by MPS interferes with the electrochemical signal of SPS, leading to a significant error when using the modified linear approximation technique (MLAT)-CVS analysis method. To evaluate their concentrations individually, a two-step CVS analysis was performed in which the total accelerator concentration ([SPS] + 1/2[MPS]) and conversion ratio were separately determined. All MPS species in the bath were oxidized to SPS by controlling the plating solution pH. Subsequent MLAT-CVS analysis successfully revealed the total accelerator concentration in the Cu plating solution. Individual SPS and MPS concentrations were thereby calculated using the conversion ratio evaluated from the difference in their relative accelerating abilities. This modified method enabled determination of the SPS concentration with <10% error, suggesting a reliable and high accuracy tool to predict pattern filling capabilities of plating solutions. Owing to the merits of high throughput, low process cost, and good film quality, Cu electroplating has a wide application, from traditional Cu foil production to state-of-the-art semiconductor metallization processes. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] The Cu plating solution typically contains small amounts of organic additives, 1-16 which enhance the uniformity, 13 brightness, 14 and mechanical properties of the Cu film. 15 In addition, for particular application to damascene Cu plating, the additives enable bottom-up filling at trenches or vias by controlling the relative deposition rates of Cu at the top and bottom of the features.1-12 For this application, the organic additives are grouped as the accelerator, suppressor, and leveler based on their electrochemical behaviors and their roles in pattern filling.One of the most widely used accelerators is bis-(sulfopropyl) disulfide (SPS), a dimer of 3-mercapto-1-propane sulfonate (MPS). Acceleration by SPS in Cu superfilling has been explained by the competitive adsorption theory [17][18][19][20][21] or by the catalytic action caused by the reduction of cupric ions. 22,23 In the competitive adsorption theory, acceleration is regarded as a recovery of the deposition rate previously suppressed by the polyethylene glycol (PEG)-Cl inhibition layer, and recovery occurs through the displacement of the PEG-Cl layer with SPS.17-19 A recent study revealed that the acceleration is a result of the dissociative adsorption of SPS with displacement of the well-ordered Cl − layer. 20,21 MPS, a dissociated product of SPS, reconverts to SPS with re...

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Section: ) Concentration Of Total Accelerating Compounds (C T )mentioning

confidence: 99%

Section: ) Concentration Of Total Accelerating Compounds (C T )mentioning

confidence: 99%

High Accuracy Concentration Analysis of Accelerator Components in Acidic Cu Superfilling Bath

Choe

Kim

et al. 2015

J. Electrochem. Soc.

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“…Locally crowded accelerator in the trench enhances the deposition rate and makes the superfilling. [8][9][10] Some organic accelerators, for example, 3-mercapto-1-propane-sulfonic acid ͑MPSA͒, 8,[11][12][13] bis͑3-sulfopropyl͒ disulfide, disodium salt ͑SPS͒, 9,10,12,14,15 and 3-N,N-dimethylaminodithiocarbamoyl-1-propanesulfonic acid ͑DPS͒ 16 are known as superfilling-capable accelerators. In Ag electroplating, there has been little research about accelerators.…”

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confidence: 99%

Acceleration Effect of CuCN in Ag Electroplating for Ultralarge-Scale Interconnects

Cho

Lee

Kim

et al. 2007

Electrochem. Solid-State Lett.

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The addition of CuCN accelerated the deposition rate in cyanide-based Ag electroplating. The catalytic effect came from the high-order complexation of Cu with the free CN − ions in electrolyte. It changed the equilibrium state of the electrolyte, presented as an increase in the amount of Ag͑CN͒ 2 − compared to Ag͑CN͒ 3 2− . Because Ag͑CN͒ 2 − could be reduced more easily, Ag electroplating was accelerated. Fourier transform infrared analysis showed the equilibrium change with the increase in Ag͑CN͒ 2 − peak according to the CuCN addition. For superfilling, it is necessary to localize the complexation on the Cu surface.

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“…12 The electrochemical deposition on thiolate pre-patterned surface has been reported several times for the electrodeposition of metals, including nikel electrodeposited on gold, 13,14 gold/ silver electrodeposited on gold, 15,16 and Cu electrodeposited on printed SAM. 17 Recently, Seo et al reported nanoshaving combined with silver electrodeposition on Au(111). 18 Here, we investigate for the first time how, by confining the growth of CdS thin films by combined ECALE, CdS nanoclusters grow and self-organizes into an ordered pattern organized at nanoscale.…”

mentioning

confidence: 99%

Two-Dimensional Self-Organization of CdS Ultra Thin Films by Confined Electrochemical Atomic Layer Epitaxy Growth

Cavallini¹,

Facchini²,

Albonetti³

et al. 2006

J. Phys. Chem. C

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We present a method that uses patterned self-assembled monolayers (SAMs) of alkanethiolates on silver as templates to fabricate ordered two-dimensional arrays of solid CdS nanoclusters. The CdS is grown by electrochemical atomic layer epitaxy inside sub-micrometric stripes of hexadecanthiol SAM fabricated by microcontact printing. CdS ultrathin films grow and self-organize into an ordered pattern of nanoclusters. This pattern exhibits both lithographically imposed ordered structures and a self-affine structure along the direction perpendicular to the stripes. On the contrary, along the direction parallel to the stripes no spatial correlation among the clusters has ever been observed.II-VI semiconductors are well-known materials used for many applications in science and technology. They have special relevance on sensors, 1 photovoltaic, 2 photoelectrochemical cells 3 and more generally nanoscience. 4 Several deposition techniques have been used to grow thin films of II-VI semiconductors, among them, chemical vapor deposition, 5 molecular beam epitaxy, 6 reactions in LangmuirBlodgett films, 7 electrochemical atomic layer epitaxy (ECALE), 8 and pulsed electrochemical deposition. 9 All of these methods are flexible and capable of generating supported planar arrays of a variety of semiconductor nanocrystallites. However, they have limited control in size distribution and spatial arrangement while the technology requires the control of these parameters. 10 The fabrication of ordered two-dimensional arrays of II-VI semiconductor microparticles has been reported using confined precipitation 11 and direct microcontact printing of CdS nanoclusters previously synthesized. 12 The electrochemical deposition on thiolate pre-patterned surface has been reported several times for the electrodeposition of metals, including nikel electrodeposited on gold, 13,14 gold/ silver electrodeposited on gold, 15,16 and Cu electrodeposited on printed SAM. 17 Recently, Seo et al. reported nanoshaving combined with silver electrodeposition on Au(111). 18 Here, we investigate for the first time how, by confining the growth of CdS thin films by combined ECALE, CdS nanoclusters grow and self-organizes into an ordered pattern organized at nanoscale. This pattern exhibit both lithographically imposed ordered structures and a self-affined structuration 19 along preferential directions.ECALE technique exploits the underpotential deposition (UPD) process to synthesize material at the working electrode. 20 The method is based on the alternate electrodeposition of the elements that form the compound at underpotential (see Figure 1). The UPD is a surface-limited phenomenon whereby, the deposition of one element occurs at a potential preceding the Nerstian equilibrium value. The layer-by-layer electrodeposition on single-crystal faces allows submonolayer control of film thickness and yields semiconducting nanostructures of high crystallinity. 21 Here, we confined the growth of CdS by ECALE inside submicrometric stripes of hexadecanthiol SAM obtained ...

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Superfilling Evolution in Cu Electrodeposition

Cited by 69 publications

References 15 publications

High Accuracy Concentration Analysis of Accelerator Components in Acidic Cu Superfilling Bath

High Accuracy Concentration Analysis of Accelerator Components in Acidic Cu Superfilling Bath

Acceleration Effect of CuCN in Ag Electroplating for Ultralarge-Scale Interconnects

Two-Dimensional Self-Organization of CdS Ultra Thin Films by Confined Electrochemical Atomic Layer Epitaxy Growth

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