Three-Additive Model of Superfilling of Copper

Cao, Yang; Taephaisitphongse, Premratn; Chalupa, Radek; West, Alan C.

doi:10.1149/1.1377898

Cited by 165 publications

(144 citation statements)

References 14 publications

(26 reference statements)

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“…Two factors confirmed that SPS was adsorbed at the bottom of the trenches; (1) low adsorption density of L2, because of the negligible convection and (2) low concentration of S2 with a lower diffusion coefficient compared to Cu 2+ or SPS. 34,35 SPS was also accumulated at the bottom-corner of the trenches in the stationary condition, forming a rounded growing surface until 10 min of filling time. The co-adsorption of S2 and L2 severely suppressed Cu deposition at the top and lateral wall where the strong convective flow was applied.…”

Section: Resultsmentioning

confidence: 99%

Bottom-up Filling of through Silicon Vias Using Galvanostatic Cu Electrodeposition with the Modified Organic Additives

Kim

Choe

Cho

et al. 2014

J. Electrochem. Soc.

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The chemically synthesized suppressor and leveler are added together with bis(3-sulfopropyl)disulfide (SPS) to galvanostatically fill up the trenches with the similar dimensions to those of the through silicon vias. In our previous study, the deposition of the coarse-grained Cu was indicated as a drawback of the synthesized additives, i.e., polyoxy polymer with amine terminal groups and pyridine derivatives containing additional amine groups. In this study, the modified chemistry of organic additives is used, enabling the bottom-up filling of trenches and improving the microstructure of the deposited Cu. The conversion of the functional groups from amine to hydroxyl groups in both the suppressor and leveler, and the uniform adsorption of modified suppressor improved the microstructure of the deposited Cu. The void-free trench filling is induced by the selective adsorption and accumulation of SPS at the bottom and negligible deposition on the top and side-walls of the trenches. Based on the filling mechanism, the trenches with 9 μm width and 50 μm depth are galvanostatically filled in ≤20 min. Intensive researches have been focused on the fabrication of 3-dimensional (3D) interconnection among electronic devices to achieve a high-density integration and multifunctional single device.1-3 The metallization of through silicon vias (TSVs), one of a promising technology for the 3D packaging, is expected to enhance the operation speed and performance of the microelectronic devices.4-8 A void-free filling of the TSVs by Cu electrodeposition with proper organic additives chemistry has been actively investigated to reduce processing time. 9-11A concentration gradient of suppressing agent, high at the via top while decreasing gradually toward the via bottom, typically induces a bottom-up via filling. The Cu deposit according to the filling time typically reveals a V-shaped profile reflecting the gradient of additive coverage. [12][13][14] Recently, an extreme bottom-up filling of the vias was achieved using one component of additive, suppressor, resulting in a clearly flat filling profile rather than the V-shape. 15,16 Based on the previous results, L. Yang et al. reported that the difference in the adsorption density of suppressing agents between the via top and bottom was required for a void-free bottom-up filling. 17Moreover, the accumulation of accelerator at the bottom of the via was also highlighted in understanding the filling mechanism. In the case of recessed features with submicrometer dimensions, accelerators including bis(3-sulfopropyl)disulfide (SPS) promoted copper deposition, enabling the superconformal filling in the combination with suppressors, based on a curvature-enhanced-accelerator coverage (CEAC) mechanism.18-26 However, the same additive composition or deposition method used in the CEAC model itself mostly failed in the void-free filling of the TSVs. Therefore, additional steps including the selective deactivation of the adsorbed SPS on the top of the vias were introduced to improve the filling perf...

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Section: Resultsmentioning

confidence: 99%

Bottom-up Filling of through Silicon Vias Using Galvanostatic Cu Electrodeposition with the Modified Organic Additives

Kim

Choe

Cho

et al. 2014

J. Electrochem. Soc.

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“…[1][2][3][4][5][6] They can be divided into two types. In one type, the additive has a promotional effect on copper deposition and it is concentrated in the bottom of the trench.…”

Section: Filling Modelmentioning

confidence: 99%

Electrochemical and Simulative Studies of Trench Filling Mechanisms in the Copper Damascene Electroplating Process

et al. 2002

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The role of additives in copper electroplating baths in the damascene process has been investigated. We proposed a bottom-up filling model and confirmed it by comparing the experimental and simulation results. Janus Green B and Basic Blue 3 which absorb on the copper surface and suppress copper deposition were examined for additive use to improve filling capability. Damascene copper grew uniformly in the bath that contained Basic Blue 3. But it grew preferentially from the bottom of the trench for Janus Green B. Addition of Janus Green B produced a continuous concentration gradient in the sub-micron trench when the additive's diffusion rate and consumption rate on the copper surface were well balanced. We estimated filling profiles from numerical simulation using parameters that were determined by an electrochemical method. These profiles agreed well with the experimental results.

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“…In the electronics and electrical industries, additives can include suppressors, accelerators and levellers to produce desirable coatings. 6 Common examples include polypropylene glycol, [7][8][9] bis(3-sulphopropyl) disulphide, nitrogen containing aromatic compounds, 10,11 thiourea, 12 gelatine, 13 3-mercapto-1-propanesulphonate 14,15 and chloride ion. 16 Such chemicals are added in small quantities and can realise an improved deposit quality involving the appearance of the plated metal (surface brightness), a modified coating structure together with physical properties (e.g.…”

Section: Introductionmentioning

confidence: 99%

Electrodeposition of copper from mixed sulphate–chloride acidic electrolytes at a rotating disc electrode

Low

León

Walsh

2014

Transactions of the IMF

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The effect of chloride ion on the deposition of copper from low metal concentrations in aqueous, acid sulphate solutions was investigated. . Linear sweep voltammetry was carried out under well defined flow conditions at a smooth platinum rotating disc electrode. The progressive transition from a single, two-electron reaction for the reduction of Cu(II)RCu(0) to two, single-electron reactions for the reduction sequence: Cu(II)RCu(I)RCu(0) was clearly evident as the chloride ion concentration increased. The charge transfer and mass transport characteristics of these reactions were evaluated. The formal potential for the Cu(II) reduction to Cu(I), the shift in the potential region for complete mass transport controlled reduction of Cu(I) to Cu(0) and the potential for hydrogen evolution at the deposited copper were also studied. A semi-logarithmic relationship between exchange current density and half-wave potential for Cu(II)RCu(I) with chloride ion was achieved when the Cl 2 /Cu(II) ratio in the electrolytes exceeded 2, due to the presence of the Cu(I) dichlorocuprous anion, CuCl { 2 .

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Three-Additive Model of Superfilling of Copper

Cited by 165 publications

References 14 publications

Bottom-up Filling of through Silicon Vias Using Galvanostatic Cu Electrodeposition with the Modified Organic Additives

Bottom-up Filling of through Silicon Vias Using Galvanostatic Cu Electrodeposition with the Modified Organic Additives

Electrochemical and Simulative Studies of Trench Filling Mechanisms in the Copper Damascene Electroplating Process

Electrodeposition of copper from mixed sulphate–chloride acidic electrolytes at a rotating disc electrode

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