Effect of Non-Ionic Surfactant on Copper Dishing and Dielectric Erosion Correction in Alkaline Barrier CMP Solution Free of Inhibitors

Self Cite

With the development of ultra-large scale integrated circuits, chemical mechanical planarization (CMP) has been one of the most critical processes to achieve global planarization. The ionic strength of slurry is one of the key factors influencing the material removal rate and surface quality during CMP process. In this paper, potassium nitrate was used to enhance ionic strength in baseline slurry, and the removal mechanism of copper and TEOS (tetraethylorthosilicate) were investigated. The results showed that, when the potassium ionic strength was 100mM, TEOS and copper removal rate can reach 768Å/min and 395Å/min respectively, and the removal rate selectivity ratio was 1.98 which can match well with the industrial production requirement. On pattern wafer, after polishing 60s, the dishing and erosion were amended to be 570 ± 50Å and 195 ± 30Å respectively, and the number of total defects was about 9. Such results provide guiding significance for industrial production.

Section: The Suitable Potassium Ionic Strength Of Slurrymentioning

confidence: 99%

“…Thus, good slurry is required to realize the appropriate rate ratio and reduce the dishing and erosion formation level. 13 Defects are a major concern in any semiconductor unit process. During the development and optimization process of slurries, the major propose is to reduce the defects.…”

mentioning

confidence: 99%

Improvement of Barrier CMP Performance with Alkaline Slurry: Role of Ionic Strength

Wang

Niu

Liu

et al. 2018

Self Cite

“…Similar to Cu, the Reactions 9, 10 occurred on cobalt surface. 17 macromolecules, forming a soluble Co-R(NH 2 ) 2 complex [18][19][20] (Reaction 11), which caused corrosion on the Co surface, as showed in Figure 4d. So, Co RR increased.…”

Section: R(nhmentioning

confidence: 99%

Effect of Chelating Agent and Surfactant on TaN CMP in Weakly Alkaline Slurry

Xiao

Pan

Tian

et al. 2018

Self Cite

Co/TaN has been considered as one of the most promising candidates for barrier layers with the feature size of integrated circuit (IC) shrinking to 14 nm and below. The present work investigates the effect of chelating agent and non-ionic surfactant on Co/Cu/TaN CMP in weakly alkaline slurry without any oxidizer. The results show that TaN removal rate increases to the peak value 526 Å/min as the chelator concentration is 1ml/L. That is due to the formation of the water-soluble complex on the surface of TaN. What's more, the TaN removal rate reaches to 501 Å/min and the root mean square roughness (Sq) of TaN is 0.654 nm when non-ionic surfactant concentration is 10 ml/L under the system of 1 ml/L of the chelator. Meanwhile, by the cross-over experiment, it is when slurry is composed of 5 wt% abrasive content, 1 ml/L chelator and 10 ml/L non-ionic surfactant at pH 10 that removal selectivity of Co:Cu and TaN:Cu are comparatively higher and closer (Co:Cu∼2.74:1, TaN:Cu∼2.61:1) along with a good surface quality is obtained.

“…Copper (Cu) chemical mechanical polishing (CMP) has become the key processing step in the dual-damascene technique of Cu wring for integrated circuit manufacture. 1,2 The whole CMP process includes bulk Cu removal and residual Cu (soft landing) removal with a short of over polishing, as well as barrier and dielectric layer removal, 3 as shown in Fig. 1.…”

mentioning

confidence: 99%

“…For Cu film CMP, a lower step height is obtained while ensuring a high RR to ensure that polishing defects of subsequent barrier layers are reduced. 2,3 However, there are few studies on the synergistic effect of mixed inhibitors on step height of Cu film CMP. So, the synergistic relationship of Ammonium dodecyl sulfate (ADS) and TAZ in a H 2 O 2 based weakly alkaline slurry during the Cu CMP process on step height reduction was studied in this paper.…”

mentioning

confidence: 99%

Synergistic Action Mechanism and Effect of Ammonium Dodecyl Sulfate and 1,2,4-triazole in Alkaline Slurry on Step Height Reduction for Cu CMP

Yang

Niu

Zhou

et al. 2020

Self Cite

For the copper (Cu) chemical mechanical polishing (CMP) of integrated circuit Cu wiring, the removal rate (RR) in the concave is lower because of the protecting of inhibitor in the slurry, and the step height is reduced by the high RR different between convex and concave, thus realizing planarization. With the decrease of technology node and the shortcomings of traditional inhibitors, new environmental inhibitors have become the focus of research. The synergistic inhibiting effect of ammonium dodecyl sulfate (ADS) and 1,2,4-triazole (TAZ) in the H2O2 based weakly alkaline slurry during the Cu film CMP process was studied. Electrochemistry, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) measurements were used to analyze the reaction mechanism between Cu and mixed inhibitors. It was found that ADS was absorbed on the Cu surface via electrostatic interactions, by which a thin porous film with small openings was formed. Then chemisorbed TAZ molecules effectively filled up the small openings, and a compact passivating film was formed to protect the Cu surface. Based on the background slurry, incorporation of 0.1 wt% ADS + 0.003 wt% TAZ (bulk) and 0.1 wt% ADS + 0.005 wt% TAZ (soft landing) at pH = 8.5 in this slurry, lower step height was achieved dropping from the initial 3800 Å to 654 Å, and the slurry can be stable for at least three days. Such results indicate that mixed inhibitors may become a trend of industrial application, and such research has certain guiding significance for industrial production.