Role of Ammonium Ions in Colloidal Silica Slurries for Ru CMP

Abstract

The chemical mechanical polishing (CMP) of ruthenium (Ru) based barrier layer has been a pivotal process in the manufacture of a novel copper (Cu) interconnect structure. This paper mainly investigated the role of NH4+ in colloidal silica slurries for Ru CMP. The polishing results show that the Ru removal rate increases with the increasing concentration of NH4+. The influence mechanism of NH4+ on removal rate of Ru was investigated by electrochemistry, scanning electron microscope (SEM) and zeta potential. It is revealed that the NH4+ can promote the surface corrosion rate of Ru by forming a water-soluble Ru-NH4 complex with Ru oxide, meanwhile can also result in the neutralization of the zeta potentials of both silica particles and the Ru surface, and thus can lead to the decrease of the electrostatic repulsive force and the increase of the mechanical abrasion intensity between silica particles and Ru surface. Further, the surface quality of the polished Ru wafer and slurry stability were evaluated, and the results show that the addition of an appropriate amount of NH4+ can achieve a low surface roughness of Ru and a high slurry stability.

Surface corrosion inhibition effect and action mechanism analysis of 5-methyl-benzotriazole on cobalt-based copper film chemical mechanical polishing for GLSI

“…Generally speaking, the decrease of OCP indicates the increase of metal activity, and the greater the possibility of metal surface reaction. When the anodic reaction of the metal is boosted or the cathodic reaction is inhibited, the OCP will decrease, conversely, the OCP will increase [19,27]. To sum up, the introduction of TTA inhibits the activity of Cu to a certain extent and weakens the reaction of Cu in the slurry.…”

Effect of ethylenediamine on CMP performance of ruthenium in H2O2-based slurries

“…Ruthenium is a chemically stable transition metal with a high melting point (2250 C), a resistivity (7.1 mU cm) lower than that of Ta (13.1 mU cm), and excellent adhesion with copper. [5][6][7][8][9][10][11] More importantly, the continuous copper lm can be conformally and directly deposited on the ruthenium surface, while no intermetallic compound is formed between copper and ruthenium. 7,9,12,13 Ruthenium, being a chemically stable and hard metal, is difficult to achieve the high removal rate in CMP process.…”

“…[5][6][7][8][9][10][11] More importantly, the continuous copper lm can be conformally and directly deposited on the ruthenium surface, while no intermetallic compound is formed between copper and ruthenium. 7,9,12,13 Ruthenium, being a chemically stable and hard metal, is difficult to achieve the high removal rate in CMP process. To meet the requirements of efficient ruthenium removal, the researchers screened a number of oxidizers, such as KMnO 4 (potassium permanganate), KClO 4 (potassium perchlorate), NaIO 4 (sodium periodate), K 3 [Fe(CN) 6 ] (potassium ferricyanide), potassium peroxymonosulfate (oxone), K 2 S 2 O 8 (potassium persulfate), KIO 4 (potassium periodate), (NH 4 ) 2 S 2 O 8 (ammonium persulphate) and H 2 O 2 (hydrogen peroxide), among which KIO 4 and H 2 O 2 receive widespread attention.…”

“…To meet the requirements of efficient ruthenium removal, the researchers screened a number of oxidizers, such as KMnO 4 (potassium permanganate), KClO 4 (potassium perchlorate), NaIO 4 (sodium periodate), K 3 [Fe(CN) 6 ] (potassium ferricyanide), potassium peroxymonosulfate (oxone), K 2 S 2 O 8 (potassium persulfate), KIO 4 (potassium periodate), (NH 4 ) 2 S 2 O 8 (ammonium persulphate) and H 2 O 2 (hydrogen peroxide), among which KIO 4 and H 2 O 2 receive widespread attention. [7][8][9]12,[14][15][16][17][18][19][20][21] H. Cui et al 22 studied the effect of various oxidizers on the removal rate of ruthenium from the perspective of surface corrosion and oxidation. The experimental results suggested that the existence of IO 4…”

Surface Interaction Effect and Mechanism of Methionine Derivatives as Novel Inhibitors for Alkaline Copper CMP: Insights from Molecular Simulation and Experimental Analysis

“…Copper (Cu) has become a desirable interconnect material and is widely used in giant-large integrated circuits (GLSI) due to its superior conductivity, low resistivity, and outstanding electromigration resistance, thereby meeting the requirements of different feature sizes. 1,2 Chemical mechanical polishing (CMP) has become the most effective technique for global and local planarization of multilayer Cu interconnects. 3 The CMP process involves a combination of chemical and mechanical action to remove excess material from the Cu interconnect layer, providing a smoother and more uniform surface for the underlying multilayer metalized structure.…”