Polishing composition for semiconductor processing polishing composition preparation method, and semiconductor device manufacturing method to which polishing composition is applied
The present invention relates to a polishing composition for a semiconductor process, a method of preparing the polishing composition, and a method of fabricating a semiconductor device using the polishing composition. The polishing composition for a semiconductor process contains abrasive particles, an accelerator, and a stabilizer. The polishing composition has excellent long-term storage stability because the particles contained therein do not aggregate even after the polishing composition is stored at 60° C. or higher for a long time. In addition, the polishing composition may be applied to a process of polishing an amorphous carbon layer, may exhibit a high removal rate, prevent carbon residue generated during the polishing process from being adsorbed onto a semiconductor substrate, and prevent contamination of a polishing pad. The present invention may also provide a method of fabricating a semiconductor device using the polishing composition for a semiconductor process.
1. A polishing composition for a semiconductor process, comprising:
abrasive particles;
an accelerator; and
a stabilizer,
wherein the abrasive particles have an average diameter of 70 nm to 120 nm,
wherein the polishing composition has a removal rate of an amorphous carbon layer of 110 Å/min to 250 Å/min,
wherein the removal rate of an amorphous carbon layer is determined under the following measurement conditions: an amorphous carbon layer (ACL) having a thickness of 2000 Å, a polishing time of 60 seconds, an applied pressure of 2 psi, a carrier speed of 87 rpm, a platen speed of 93 rpm, and a polishing composition flow rate of 200 mL/min,
wherein the polishing composition has a cohesion index (CI) of 0.5 to 5 as calculated by Equation 1 below:
CI
=
Saf
Sai
[
Equation
1
]
wherein
Sai is an average particle diameter of the abrasive particles contained in the polishing composition for a semiconductor process, measured by a dynamic light scattering particle size analyzer, and
Saf is an average particle diameter of the abrasive particles contained in the polishing composition for a semiconductor process, measured by the dynamic light scattering particle size analyzer after keeping the polishing composition at 60° C. for 17 hours and then cooling the polishing composition at 15 to 25° C.
2. The polishing composition of claim 1 , wherein the abrasive particles are selected from the group consisting of metal oxide particles, organic particles, organic-inorganic composite particles, and mixtures thereof.
3. The polishing composition of claim 1 , wherein the accelerator is selected from the group consisting of anionic small molecules, anionic polymers, hydroxyl acids, and cerium salts.
4. The polishing composition of claim 1 , wherein the stabilizer is an amino acid.
5. The polishing composition of claim 1 , further containing a surfactant.
6. The polishing composition of claim 1 , further containing a pH adjusting agent.
7. The polishing composition of claim 1 , wherein a rate of increase in the average diameter of the abrasive particles is 0.5% to 30% as calculated by Equation 2 below:
(
Saf
-
Sai
)
Sai
×
100
wherein
Sai is the average particle diameter of the abrasive particles contained in the polishing composition, measured by a dynamic light scattering particle size analyzer, and
Saf is the average particle diameter of the abrasive particles contained in the polishing composition, measured by the dynamic light scattering particle size analyzer after keeping the polishing composition at 60° C. for 17 hours and then cooling the polishing composition at 15 to 25° C.
8. A method of preparing the polishing composition of claim 1 , the method comprising steps of:
a) preparing a polishing solution by mixing a stabilizer and an accelerator in a solvent;
b) adjusting a pH of the polishing solution to 2 to 5 by adding a pH adjusting agent to the polishing solution; and
c) mixing a surfactant and abrasive particles with the polishing solution having a pH of 2 to 5,
wherein the polishing composition has a cohesion index (CI) of 0.5 to 5 as calculated by Equation 1 below:
CI
=
Saf
Sai
[
Equation
1
]
wherein
Sai is an average particle diameter of the abrasive particles contained in the polishing composition for a semiconductor process, measured by a dynamic light scattering particle size analyzer, and
Saf is an average particle diameter of the abrasive particles contained in the polishing composition for a semiconductor process, measured by the dynamic light scattering particle size analyzer after keeping the polishing composition at 60° C. for 17 hours and then cooling the polishing composition at 15 to 25° C.
9. The method of claim 8 , wherein step a) comprises:
preparing a mixed solution by mixing the stabilizer with the solvent; and
preparing the polishing solution by mixing the mixed solution with the accelerator.
10. A method of fabricating a semiconductor, the method comprising steps of:
1) Providing a polishing pad comprising a polishing layer;
2) Supplying the polishing composition of claim 1 ; and
3) Polishing a polishing target while allowing the polishing target and the polishing pad to rotate relative to each other so that a polishing-target surface of the polishing target comes into contact with a polishing surface of the polishing layer,
wherein the polishing composition contains abrasive particles, an accelerator, and a stabilizer, and has a cohesion index (CI) of 0.5 to 5 as calculated by Equation 1 below:
CI
=
Saf
Sai
[
Equation
1
]
wherein
Sai is an average particle diameter of the abrasive particles contained in the polishing composition for a semiconductor process, measured by a dynamic light scattering particle size analyzer, and
Saf is an average particle diameter of the abrasive particles contained in the polishing composition for a semiconductor process, measured by the dynamic light scattering particle size analyzer after keeping the polishing composition at 60° C. for 17 hours and then cooling the polishing composition at 15 to 25° C.