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

Abstract

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.

Surface Corrosion Inhibition Effect and Action Mechanism Analysis of 5-Methyl-Benzotriazole on Cobalt-Based Copper Film Chemical Mechanical Polishing for GLSI

“…This is because when the slurry contains only glycine and H 2 O 2 , oxide film forms on the Cu surface, and it is a porous, discontinuous passivation film (CuO, Cu 2 O). 20 In contrast, there are almost no corrosion pits on the Cu surface when 400 ppm TTA is added as shown in Fig. 12b, indicating that TTA has a good passivation effect.…”

“…14 Therefore, corrosion inhibitor needs to be introduced to obtain high planarization performance. 15 Currently, compound corrosion inhibitors in Cu CMP are gradually becoming a hot topic of research, [16][17][18][19][20] but their complex composition makes the mechanistic study difficult. Selecting a single inhibitor which can both inhibit the corrosion of Cu and Co and simplify the composition of slurry is still the direction of slurry optimization.…”

Role of Potassium Tolyltriazole as an Inhibitor in H2O2-Based Slurry on Cu/Ru Patterned Wafer CMP

“…There is a stable current between a certain range of potentials, which proves that the corrosion inhibition effect of copper is related to the formation of a protective film. 17,18,[20][21][22][23] The main cathodic reactions were the reactions of oxygen reduction as follows: 23…”

A High Antibacterial Weakly Alkaline Barrier Slurry with the Tunable Selectivity

“…It also indicates that the MRRs of Cu and Ta increase with the H 2 O 2 concentration increasing because H 2 O 2 modifies the metal surface to promote chemical dissolution while reduces the surface hardness of oxide films which are then removed easily through mechanical force. The oxidizing reactions in the alkaline solution are as follows: 20,21 Cu H O CuO H O 1…”