Copper chemical mechanical polishing solutions using sulfonated amphiprotic agents
View Patent ↗A family of slurries useful in modifying exposed surfaces of wafers for semiconductor fabrication are provided along with methods of modifying exposed surfaces of wafers for semiconductor fabrication utilizing such a family of working slurries, and semiconductor wafers. The slurries of the invention are a solution of initial components, the components comprising: a sulfonated zwitterion selected from 2-(N-Morpholino)ethanesulfonic acid, (3-[N-Morpholino])propanesulfonic acid, 2-[(2-Amino-2-oxoethyl)amino]ethanesulfonic acid, Piperazine-N, N′-bis(2-ethanesulfonic acid), 3-(N-Morpholino)-2-hydroxypropanesulfonic acid, N ,N-Bis(2-hydroxyethyl)-2-aminoethanesulfonic acid, 3-(N-Morpholino)propanesulfonic acid, N-(2-Hydroxyethyl)piperazine-N′-(2-ethanesulfonic acid), N-Tris(hydroxymethyl)methyl-2 aminoethanesulfonic acid, 3-[N ,N-Bis(2-hydroxyethyl)amino]-2-hydroxypropanesulfonic acid, 3-[N-Tris(hydroxymethyl)methylamino)-2-hydroxypropanesulfonic acid, N-(2-hydroxyethyl)piperazine-N′-(2-hydroxypropanesulfonic acid), Piperazine-N ,N′-bis(2-hydroxypropanesulfonic acid), N-(2-Hydroxyethyl)piperazine-N′-(3-propanesulfonic acid), N-Tris(hydroxymethyl)methyl-3-aminopropanesulfonic acid, 3-[(1,1-Dimethy 1-2-hydroxyethyl)amino]-2-hydroxypropanesulfonic, acid, 2-(N-Cyclohexylamino)ethanesulfonic acid, 3-(Cyclohexylamino)-2-hydroxy-I-propanesulfonic acid, 2-Amino-2-methyl-I-propanol, 3-(Cyclohexylamino)-1-propanesulfonic acid, an oxidizing agent; optionally, a passivating agent; optionally a chelating agent, optionally abrasive particles, optionally a surfactant, optionally a secondary buffering agent and water. The method of the invention comprises the steps of: a) providing a wafer comprising a first material having a surface etched to form a pattern and a second material deposited over the surface of the first material; b) contacting the second material of the wafer with abrasive in the presence of the working slurry; and c) relatively moving the wafer or polishing pad or both while the second material is in contact with the slurry and abrasive particles until an exposed surface of the wafer is planar and comprises at least one area of exposed first material and one area of exposed second material.
1. A method of modifying a surface of a wafer, via abrasive removal of material, suited for fabrication of a copper based semiconductor device comprising the steps of:
a. providing a wafer comprising a first material having a surface etched to form a pattern and a second material deposited over the surface of the first material;
b. contacting the second material of the wafer with polishing pad in the presence of a working slurry; and
c. relatively moving the wafer or polishing pad, to abrasively remove material, while the second material is in contact with a polishing pad until an exposed surface of the wafer is planar and comprises at least one area of exposed first material and one area of exposed second material,
wherein the working slurry is comprised of:
(a) a sulfonated zwitterions,
(b) an oxidizing agent,
(c) a liquid carrier,
(d) optionally, inorganic polishing particles,
(e) optionally, a chelating agent,
(f) optionally, a secondary buffering agent,
(g) optionally, a passivating agent,
(h) optionally, surfactants, viscosity modifiers, wetting agents, lubricants, soaps, and the like, and
(i) optionally, a stopping compound.
2. The method of claim 1 wherein the polishing particles are in the composition.
3. The method of claim 1 wherein the polishing particles are fixed on the polishing pad.
4. The method of claim 1 wherein no polishing particles are used.
5. The method of claim 1 wherein the polishing pad comprises a slurry and a polymer pad, the slurry comprising a plurality of loose abrasive particles dispersed in a slurry, the slurry contacting the metal layer of the wafer by the application of the polishing pad.
6. The method of claim 1 wherein the first material is a dielectric material and the second material is a conductive copper based material.
7. The method of claim 1 , wherein the wafer further comprises a barrier layer covering the dielectric material.