Slurry composition for polishing tungsten
A slurry composition for polishing tungsten is provided. The slurry composition for polishing tungsten may include a water-soluble polymer, abrasive particles and an etching adjuster.
1. A slurry composition for polishing tungsten, the slurry composition comprising:
at least one water-soluble polymer selected from the group consisting of polystyrene sulfonic acid, polyvinyl sulfonic acid, polyacrylamide methylpropane sulfonic acid, poly-α-methylstyrene sulfonic acid, poly-ρ-methylstyrene sulfonic acid and salts thereof,
wherein the water-soluble polymer is present in the slurry composition in an amount of from 0.01 wt % to 0.6 wt % based on the total weight of the slurry composition;
abrasive particles; and
an etching adjuster in an amount of from 0.01 wt % to 0.5 wt % based on the total weight of the slurry composition,
wherein the etching adjuster is at least one of a compound having a hydrophilic index (HPI) value equal to or less than “70” and a compound having a hydrophobic index (HBI) value equal to or greater than “30,” wherein the HPI value and the HBI value are defined by the following equations:
HPI
=
Molecular
weight
of
hydrophilic
functional
group
Total
Molecular
weight
of
compound
×
100
,
and
HBI
=
Molecular
weight
of
hydrophobic
functional
group
Total
Molecular
weight
of
compound
×
100
,
wherein a static etch rate (SER) of a surface of tungsten polished using the slurry composition is equal to or less than 150 angstroms per minute ({acute over (Å)}/min).
2. The slurry composition of claim 1 , wherein the water-soluble polymer is present in an amount of 0.01% by weight (wt %) to 5 wt % in the slurry composition.
3. The slurry composition of claim 1 , wherein the abrasive particles comprise at least one selected from the group consisting of a metal oxide, a metal oxide coated with an organic material or inorganic material and the metal oxide in a colloidal phase, and
wherein the metal oxide comprises at least one selected from the group consisting of silica, ceria, zirconia, alumina, titania, barium titania, germania, mangania and magnesia.
4. The slurry composition of claim 1 , wherein the abrasive particles have a particle size of 20 nanometers (nm) to 250 nm, and comprise abrasive particles having the same particle size or at least two different particle sizes.
5. The slurry composition of claim 1 , wherein the abrasive particles are present in an amount of 1 wt % to 5 wt % in the slurry composition.
6. The slurry composition of claim 1 , wherein the etching adjuster comprises at least one selected from the group consisting of lactic acid, propionic acid, isovaleric acid, caproic acid, isobutyric acid, valeric acid, butyric acid, cyclopentanecarboxylic acid, hydroxybutyric acid, 4-amino-3-hydroxybutyric acid, dimethylsuccinic acid, methylpentanoic acid, 2-hydroxy-4-methylpentanoic acid and 1-hydroxy-1-cyclopropanecarboxylic acid.
7. The slurry composition of claim 1 , wherein the etching adjuster is present in an amount of 0.001 wt % to 1 wt % in the slurry composition.
8. The slurry composition of claim 1 , further comprising:
at least one oxidizer selected from the group consisting of hydrogen peroxide, urea hydrogen peroxide, urea, percarbonate, periodic acid, periodate, perchloric acid, perchlorate, perbromic acid, perbromate, perboric acid, perborate, permanganic acid, permanganate, persulfate, bromate, chlorate, chlorite, chromate, iodate, iodic acid, ammonium persulfate, benzoyl peroxide, calcium peroxide, barium peroxide, sodium peroxide and urea peroxide.
9. The slurry composition of claim 8 , wherein the oxidizer is present in an amount of 0.005 wt % to 5 wt % in the slurry composition.
10. The slurry composition of claim 1 , further comprising:
at least one pH adjuster selected from the group consisting of:
an acidic material including at least one selected from the group consisting of nitric acid, hydrochloric acid, phosphoric acid, sulfuric acid, hydrofluoric acid, bromic acid, iodic acid, formic acid, malonic acid, maleic acid, oxalic acid, acetic acid, adipic acid, citric acid, propionic acid, fumaric acid, lactic acid, salicylic acid, pimelic acid, benzoic acid, succinic acid, phthalic acid, butyric acid, glutaric acid, glutamic acid, glycolic acid, asparaginic acid, tartaric acid and salts thereof; and
a basic material including at least one selected from the group consisting of ammonia, ammonium methyl propanol (AMP), tetramethylammonium hydroxide (TMAH), potassium hydroxide, sodium hydroxide, magnesium hydroxide, rubidium hydroxide, cesium hydroxide, sodium hydrogen carbonate, sodium carbonate and imidazole.
11. The slurry composition of claim 1 , wherein the slurry composition has a pH ranging from 2 to 5.
12. The slurry composition of claim 1 , wherein the slurry composition is free of nitric acid.
13. The slurry composition of claim 1 , wherein a peak-to-valley roughness Rpv of a surface of tungsten polished using the slurry composition is equal to or less than 100 nm, and a root mean square roughness Rq of the surface is equal to or less than 10 nm.
14. The slurry composition of claim 1 , wherein the slurry composition is used to improve topography of tungsten.
15. The slurry composition according to claim 1 , having a pH of from 2.8 to 3.5.
16. The slurry composition according to claim 15 , wherein the etching adjuster is at least one selected from the group consisting of lactic acid, 4-amino-3-hydroxybutyric acid, propionic acid and 2-hydroxy-butyric acid.
17. The slurry composition according to claim 16 , having a particle stability of 5.24% to 8.77% and a static etch rate of from 68.9 to 124.1 Å/min.
18. The slurry composition according to claim 17 , wherein the etching adjuster is a compound having a hydrophilic index (HPI) value equal to or less than “70” and a hydrophobic index (HBI) value equal to or greater than “30”.