Investigation of the effects of byproduct components in Cu plating for advanced interconnect metallization

Koh, L.T.; You, Guoxiang; Li, C.Y.; Foo, P. D.

doi:10.1016/s0026-2692(01)00122-7

Cited by 37 publications

(32 citation statements)

References 8 publications

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“…The most common technique is cyclic voltammetry stripping (CVS). 30,31,35,37 This technique has been widely used because it is very simple and sensitive, and it does not require a long time to analyze. A drawback of this technique is the inability to distinguish the concentrations of by-products from those of additives, and these by-products could influence the performance of the plating solution.…”

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confidence: 99%

Degradation of Bis(3-sulfopropyl) Disulfide and Its Influence on Copper Electrodeposition for Feature Filling

Choe

Kim

et al. 2013

J. Electrochem. Soc.

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The degradation of bis(3-sulfopropyl) disulfide (SPS) during Cu electrodeposition and the influence of its decomposition products on the Cu film properties are investigated. SPS decomposes into 3-mercapto-1-propane sulfonic acid (MPSA) and 1,3-propane disulfonic acid (PDS) by dissociation of the disulfide bond and oxidation reactions. The MPSA seems to recombine to form SPS through a reaction with cupric ions, whereas the PDS accumulates in the plating solution without any further reactions. It was found that the net conversion from SPS to PDS reduced the acceleration effect and resulted in the deterioration of Cu feature filling. The final decomposition product, PDS, caused no remarkable changes in either the electrochemical behavior or the film properties. The deterioration in feature filling by degradation of SPS is mainly associated with the decrease in SPS concentration by decomposition and incorporation.

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Degradation of Bis(3-sulfopropyl) Disulfide and Its Influence on Copper Electrodeposition for Feature Filling

Choe

Kim

et al. 2013

J. Electrochem. Soc.

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“…These decrease the filling capability of the plating solution even though the concentration of each additive is normal. 12 An accelerator-free electrolyte has been demonstrated to be feasible to cause superfill on submicrometer via metallization to reduce the additive of the plating formula, the analytic complexity of the additives and the aging effect of the plating solution. 13,14 In this technique, the test specimen was pre-dipped into an accelerator-containing solution ͑i.e., SPS or DPS͒ to form an adlayer of the accelerator on the copper seed layer before the test specimen was transferred into an accelerator-free plating solution in which the suppressor ͑i.e., PEG + Cl − ͒ was the only additive.…”

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Microvia Filling over Self-Assembly Disulfide Molecule on Au and Cu Seed Layers

Dow

Yen

2005

Electrochem. Solid-State Lett.

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Microvia filling of a printed circuit board was achieved using an accelerator-free acid copper plating solution. The required accelerator ͑i.e., bis͑3-sulfopropyl͒ disulfide, SPS͒ for the filling procedure was adsorbed on seed layers in advance. Two metallic materials, copper and gold, were employed as the seed layers. The SPS adlayer is demonstrated to be persistently transferable from the seed layer onto the surface of as-deposited copper layer during electrodeposition. The SPS adlayer induced copper superfill of the microvia. Three kinds of microstructures of the copper deposit were observed due to the depletion of the SPS adlayer.High-density interconnections ͑HDI͒ between multilayers and microvias are used in state-of-the-art printed circuit boards ͑PCBs͒ to meet the requirements of portable electronic products. When the diameter of the microvia is less than 75 m, a fill-type metallization of the microvia must be used for reasons of reliability and signal transmission. Actually, via or trench filling by copper electroplating has been a feasible and successful process technology for forming interconnections in integrated circuit ͑IC͒ chips, because so-called bottom-up filling or superfilling behavior can be induced during electroplating. 1-3 Some specific additives, such as suppressor, accelerator, and leveler, must be concomitantly used in the plating bath to cause the superfill of the submicrometer and micrometer vias with copper electrodeposition. 4-6 These additives can interact with each other and even interact with physical factor, such as the fluid dynamics. 6,7 In other words, superfilling behavior is caused by synergistic interactions rather than a single factor or component. 6,[8][9][10] The feature of the microvia on the PCBs is much larger than those on the IC chips. However, superfill can also be performed in the microvias of PCB using the same plating additives. 6,8,9 Hence, the filling mechanism should be similar, no matter which micrometer or submicrometer features are chosen. 11 In the PCB fabrication, the volume of the plating bath greatly exceeds that designed for IC chip fabrication. Consequently, more byproducts generated from the breakdown of additives or from the side reactions of additives accumulate in the plating bath during mass production. These decrease the filling capability of the plating solution even though the concentration of each additive is normal. 12 An accelerator-free electrolyte has been demonstrated to be feasible to cause superfill on submicrometer via metallization to reduce the additive of the plating formula, the analytic complexity of the additives and the aging effect of the plating solution. 13,14 In this technique, the test specimen was pre-dipped into an accelerator-containing solution ͑i.e., SPS or DPS͒ to form an adlayer of the accelerator on the copper seed layer before the test specimen was transferred into an accelerator-free plating solution in which the suppressor ͑i.e., PEG + Cl − ͒ was the only additive. 13,14 This adsorptive mode of disulfide/thiol ...

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“…In addition, additive breakdown also occurs mainly due to electrodic reactions and oxidation by dissolved air in the bath. Both of these processes are theorized to cause an adverse effect on the coating film quality.Considerable efforts have been made in recent decades to achieve the monitor and the control of an electroplating ͑EP͒ bath: the use of hull cell and cyclic voltammetric stripping ͑CVS͒, 6,10-14 cathodic depolarization measurements, 15 "in-process" mass spectrometry ͑IPMS͒, 16,17 linear voltammetric stripping ͑LVS͒, 13,18 cyclic pulsed voltammetric stripping ͑CPVS͒, 12,19 and HPLC 4,5,7,20,21 techniques has been reported for this purpose.HPLC is probably the most direct technique for measurement of additives concentrations and for by-product monitoring. The sample typically requires some pretreatment prior to analysis on the HPLC in order to separate Cu 2+ ion peaks that may interfere with the peaks generated by the organic additives.…”

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confidence: 99%

Solid Phase Extraction–High-Performance Liquid Chromatography Detection of Organic Additives in Acidic Copper Baths

D’Urzo

Wang

Tang

et al. 2005

J. Electrochem. Soc.

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A technique has been developed for the study of the reaction mechanism and the monitoring of copper electroplating baths utilizing a combination of solid phase extraction and high-performance liquid chromatography. This method appears suitable for live electroplating bath control as well as for organic identification, concentration measurement, and reaction mechanism studies. The results from the experiments carried out with the technique described in this paper show how the monitoring of a few diagnostic peaks recovered from a live bath sample can be directly used for this purpose. Two copper sulfuric plating baths at different acidity were used for this study. The stability, degradation mechanism, and by-products of bis͑sodiumsulfopropyl͒ disulfide were addressed in Part I, while polyethylene glycol ͑PEG͒ behaviors are studied in Part II. The identification of PEG breakdown by-products was achieved in this work.The electrodeposition of Cu from acidic sulfate solutions is a well-established process used for several decades in the surfacefinishing industries. Recently, research interest for this process has been renewed because of its use during the fabrication of ultralargescale integrated circuits. This application relies on the use of complex mixtures of organics components, which are added simultaneously to the deposition bath, and whose function is to properly modify the quality of the coated metal. The more recent contributions reported the use of two 1 or three organic additives 2-4 to achieve the requirements imposed from the device scaling. In this paper, we focus on the identification and the reactivity study of a polyethylene glycol ͑PEG͒ based suppressor in a deposition bath via a combination of solid phase extraction ͑SPE͒ and high-performance liquid chromatography ͑HPLC͒ techniques that is becoming an appealing analytical tool in the field of electrodeposition science. [5][6][7][8][9] A conventional copper-plating bath contains copper sulfate, sulfuric acid, and chloride ions plus several organics additives, usually designated as brightener, suppressor, and leveler, whose function is to modify the properties of the coating. The concentrations of the additives are held within ranges strictly dependent on the application and change during the plating process as these additives likewise are consumed. In addition, additive breakdown also occurs mainly due to electrodic reactions and oxidation by dissolved air in the bath. Both of these processes are theorized to cause an adverse effect on the coating film quality.Considerable efforts have been made in recent decades to achieve the monitor and the control of an electroplating ͑EP͒ bath: the use of hull cell and cyclic voltammetric stripping ͑CVS͒, 6,10-14 cathodic depolarization measurements, 15 "in-process" mass spectrometry ͑IPMS͒, 16,17 linear voltammetric stripping ͑LVS͒, 13,18 cyclic pulsed voltammetric stripping ͑CPVS͒, 12,19 and HPLC 4,5,7,20,21 techniques has been reported for this purpose.HPLC is probably the most direct technique for measureme...

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Investigation of the effects of byproduct components in Cu plating for advanced interconnect metallization

Cited by 37 publications

References 8 publications

Degradation of Bis(3-sulfopropyl) Disulfide and Its Influence on Copper Electrodeposition for Feature Filling

Degradation of Bis(3-sulfopropyl) Disulfide and Its Influence on Copper Electrodeposition for Feature Filling

Microvia Filling over Self-Assembly Disulfide Molecule on Au and Cu Seed Layers

Solid Phase Extraction–High-Performance Liquid Chromatography Detection of Organic Additives in Acidic Copper Baths

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