Utility of dodecyl sulfate surfactants as dissolution inhibitors in chemical mechanical planarization of copper

Abstract

An important component of the slurries used in chemical mechanical planarization (CMP) is an appropriately chosen corrosion/dissolution inhibitor, which facilitates selective material removal from protrusions while protecting recessed regions of the surface. The present work demonstrates the utility of two environmentally benign anionic surfactants, sodium dodecyl sulfate (SDS) and ammonium dodecyl sulfate (ADS) as dissolution inhibitors. Using a standard slurry (1 wt% glycine with 5 wt% H 2 O 2 at pH ‫ס‬ 4.0) typically used for Cu CMP and combining measurements of open circuit potentials and contact angles with those of Cu removal rates, we show that both SDS and ADS suppress chemical dissolution and polish rates of Cu. The dissolution inhibition efficiencies of ADS and SDS measured in these experiments are found to be superior to those of benzotriazole (BTA), a traditional inhibiting agent used for copper CMP.

Investigation of dissolution inhibitors for electrochemical mechanical planarization of copper using beta-alanine as a complexing agent

“…This absorption mechanism is governed by electrostatic interactions between the positively charged Cu/Cu-oxide surface (at pH = 4.0) and the DS -anions [6][7][8]. At the 3 mM concentration of ADS used here, the adsorbed species take the form of densely packed hemimicelles, (DS À ) ad n , where n is the number of DS -ions in each unit cell [6,8].…”

“…However, all such inhibitors may not necessarily function efficiently with all the commonly used complexing agents. In addition, when used in large concentrations (C10 mM), certain dissolution inhibitors, including the commonly used benzotriazole (BTAH), tend to leave insoluble debris resulting in scratches on the finished surface [7,8]. Due to these reasons, there has been considerable interest in recent years in developing novel combinations of complexing agents and dissolution inhibitors for CMP applications [9][10][11], and these efforts are now expanding to the field of ECMP [6,7].…”

“…Previously we have studied the general surface chemistries of BTAH and ADS for CMP and ECMP of Cu using glycine as a complexing agent [6][7][8]. More recently, we have tested b-alanine as an alternative complexing agent of glycine [12], together with ADS and BTAH used as inhibitors for CMP of Cu [13].…”

Polystyrene films as barrier layers for corrosion protection of copper and copper alloys

“…Since then, many different substances on different metals and alloys have been proven to be effective against corrosion. The list includes thiols [6][7][8][9][10][11][12][13][14][15][16][17][18][19], amines [12], phosphates [20], sulfates [21], thiosulfates [22], carboxylic acids [23][24][25][26][27][28][29], hydroxamic acids [29][30][31], amino acids [32][33][34], phosphonic acids [29,35], sulfonic acids [29], silane derivatives [36], as well as heterocyclic and other compounds [16,[37][38][39][40][41][42][43][44].…”

The use of nano-/microlayers, self-healing and slow-release coatings to prevent corrosion and biofouling

“…One good example is a study on sodium dodecyl-sulfate and ammonium dodecyl-sulfate (Hong, 2005). Some authors (Lusk, 2001) suggest that SAM films of sodium S-alkyl thiosulfate (R-S-SO 3 -Na + ) and molecules with various carbon chain lengths (8, 10, 12, and 14) might be potential alternatives to the traditional thiol-based SAMs as protective layers against the corrosion of copper.…”