Patent Application
20200002607
This invention relates to the chemical mechanical planarization (CMP) for polishing oxide and doped oxide films.
In the fabrication of microelectronics devices, an important step involved is polishing, especially surfaces for chemical-mechanical polishing for the purpose of recovering a selected material and/or planarizing the structure.
For example, a SiN layer is deposited under a SiO2 layer to serve as a polish stop. The role of such polish stop is particularly important in Shallow Trench Isolation (STI) structures. Selectivity is characteristically expressed as the ratio of the oxide polish rate to the nitride polish rate. An example is an increased polishing selectivity rate of silicon dioxide (SiO2) as compared to silicon nitride (SiN).
In the global planarization of patterned structures, reducing oxide trench dishing is a key factor to be considered. The lower trench oxide loss will prevent electrical current leaking between adjacent transistors. Non-uniform trench oxide loss across die (within Die) will affect transistor performance and device fabrication yields. Severe trench oxide loss (high oxide trench dishing) will cause poor isolation of transistor resulting in device failure. Therefore, it is important to reduce trench oxide loss by reducing oxide trench dishing in CMP polishing compositions.
U.S. Pat. No. 5,876,490 discloses the polishing compositions containing abrasive particles and exhibiting normal stress effects. The slurry further contains non-polishing particles resulting in reduced polishing rate at recesses, while the abrasive particles maintain high polish rates at elevations. This leads to improved planarization. More specifically, the slurry comprises cerium oxide particles and polymeric electrolyte, and can be used for Shallow Trench Isolation (STI) polishing applications.
U.S. Pat. No. 6,964,923 teaches the polishing compositions containing cerium oxide particles and polymeric electrolyte for Shallow Trench Isolation (STI) polishing applications. Polymeric electrolyte being used includes the salts of polyacrylic acid, similar as those in U.S. Pat. No. 5,876,490. Ceria, alumina, silica & zirconia are used as abrasives. Molecular weight for such listed polyelectrolyte is from 300 to 20,000, but in overall, <100,000.
U.S. Pat. No. 6,616,514 discloses a chemical mechanical polishing slurry for use in removing a first substance from a surface of an article in preference to silicon nitride by chemical mechanical polishing. The chemical mechanical polishing slurry according to the invention includes an abrasive, an aqueous medium, and an organic polyol that does not dissociate protons, said organic polyol including a compound having at least three hydroxyl groups that are not dissociable in the aqueous medium, or a polymer formed from at least one monomer having at least three hydroxyl groups that are not dissociable in the aqueous medium.
However, those prior disclosed Shallow Trench Isolation (STI) polishing compositions did not address the importance of oxide trench dishing reducing.
It should be readily apparent from the foregoing that there remains a need within the art for compositions, methods and systems of chemical mechanical polishing that can afford the reduced oxide trench dishing and improved over polishing window stability in a chemical and mechanical polishing (CMP) process, in addition to high removal rate of silicon dioxide as well as high selectivity for silicon dioxide to silicon nitride.
The present invention provides Chemical mechanical polishing (CMP) polishing compositions, methods and systems for a reduced oxide trench dishing and thus improved over polishing window stability by introducing chemical additives as oxide trench dishing reducing additives compositions at wide pH range including acidic, neutral and alkaline pH conditions.
The present invention also provides the benefits of achieving high oxide film removal rates, low SiN film removal rates, high and tunable Oxide: SiN selectivity, lower total defect counts post-polishing, and excellent mean particle size (nm) stability.
In one aspect, there is provided a CMP polishing composition comprises:
abrasive particles selected from the group consisting of ceria-coated inorganic metal oxide particles, ceria-coated organic polymer particles, and combinations thereof;
chemical additive as oxide trenching dishing reducer,
a solvent; and
optionally
biocide; and
pH adjuster;
wherein the composition has a pH of 2 to 12, preferably 3 to 10, and more preferably 4 to 9.
The ceria-coated inorganic metal oxide particles include, but are not limited to, ceria-coated colloidal silica, ceria-coated high purity colloidal silica, ceria-coated alumina, ceria-coated titania, ceria-coated zirconia, or any other ceria-coated inorganic metal oxide particles.
The ceria-coated organic polymer particles include, but are not limited to, ceria-coated polystyrene particles, ceria-coated polyurethane particle, ceria-coated polyacrylate particles, or any other ceria-coated organic polymer particles.
The solvent includes but is not limited to deionized (DI) water, distilled water, and alcoholic organic solvents.
The chemical additives as oxide trenching dishing reducers contain at least two or more, preferably four or more, more preferably six or more hydroxyl functional groups in their molecular structures.
In one embodiment, the chemical additive has a general molecular structure as shown below:
In the general molecular structure, n is selected from 2 to 5,000, from 3 to 12, preferably from 4 to 7.
R1, R2, and R3 can be the same or different atoms or functional groups.
Each of Rs in the group of R1 to R3 can be independently selected from the group consisting of hydrogen, alkyl, alkoxy, organic group with one or more hydroxyl groups, substituted organic sulfonic acid, substituted organic sulfonic acid salt, substituted organic carboxylic acid, substituted organic carboxylic acid salt, organic carboxylic ester, organic amine groups, and combinations thereof; wherein, at least two or more, preferably four of them are hydrogen atoms.
When R1, R2, and R3 are the same and are hydrogen atoms, the chemical additive bears multi hydroxyl functional groups.
The molecular structures of some examples of such chemical additives are listed below:
In another embodiment, the chemical additive has a structure shown below:
In this structure, one —CHO functional group is located at one end of the molecule as the terminal functional group; n is selected from 2 to 5,000, from 3 to 12, preferably from 4 to 7.
Each of R1 and R2 can be independently selected from the group consisting of hydrogen, alkyl, alkoxy, organic group with one or more hydroxyl groups, substituted organic sulfonic acid, substituted organic sulfonic acid salt, substituted organic carboxylic acid, substituted organic carboxylic acid salt, organic carboxylic ester, organic amine groups, and combinations thereof.
When R1 and R2 are all hydrogen atoms, and n=3, the chemical additive is D-arabinose or L-arabinose:
When R1 and R2 are all hydrogen atoms, and n=4, the chemical additive is D-mannose or L-mannose.
In yet another embodiment, the chemical additive has a molecular structure selected from the group comprising of at least one (f), at least one (g), at least one (h) and combinations thereof;
In these general molecular structures; R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, and R14 can be the same or different atoms or functional groups.
They can be independently selected from the group consisting of hydrogen, alkyl, alkoxy, organic group with one or more hydroxyl groups, substituted organic sulfonic acid, substituted organic sulfonic acid salt, substituted organic carboxylic acid, substituted organic carboxylic acid salt, organic carboxylic ester, organic amine groups, and combinations thereof; wherein, at least two or more, preferably four or more of them are hydrogen atoms.
When R1, R2, R3 R4, R5, R6, R7 R8, R9, R10, R11, R12, R13, and R14 are all hydrogen atoms which provide the chemical additives bearing multi hydroxyl functional groups.
The molecular structures of some examples of such chemical additives are listed below:
Yet, in another embodiment, the chemical additives contain at least one six-member ring structure motif ether bonded with at least one polyol molecular unit containing multiple hydroxyl functional groups in the molecular unit structures or at least one polyol molecular unit containing multiple hydroxyl functional groups in the molecular unit structures and at least one six-member ring polyol. A polyol is an organic compound containing hydroxyl groups.
The chemical additives as oxide trenching dishing reducers contain at least two, at least four, or at least six hydroxyl functional groups in their molecular structures.
The general molecular structure for the chemical additives is shown in (a):
In one embodiment, at least one R in the group of R1 to R5 in the general molecular structure is a polyol molecular unit having a structure shown in (b):
wherein n and m can be the same or different. m or n is independently selected from 1 to 5, preferably from 1 to 4, more preferably from 1 to 3, and most preferably from 1 to 2; R6 to R9 can be the same or different atoms or functional groups; and
the rest of Rs in the group of R1 to R5 can be independently selected from the group consisting of hydrogen, alkyl, alkoxy, organic group with one or more hydroxyl groups, substituted organic sulfonic acid or salt, substituted organic carboxylic acid or salt, organic carboxylic ester, organic amine, and combinations thereof.
In another embodiment, at least one R in the group of R1 to R5 in the general molecular structure is a polyol molecular unit having a structure shown in (b); at least one R in the group of R1 to R5 in the general molecular structure is a six-member ring polyol as shown in (c):
wherein each of R10, R11, R12, R13 and R14 is independently selected from the group consisting of hydrogen, alkyl, alkoxy, organic group with one or more hydroxyl groups, substituted organic sulfonic acid or salt, substituted organic carboxylic acid or salt, organic carboxylic ester, organic amine, and combinations thereof;
and the rest of Rs in the group of R1 to R5 can be independently selected from the group consisting of hydrogen, alkyl, alkoxy, organic group with one or more hydroxyl groups, substituted organic sulfonic acid or salt, substituted organic carboxylic acid or salt, organic carboxylic ester, organic amine, and combinations thereof.
In the general molecular structure, at least two, preferably four, more preferably six of the Rs in the group of R1 to R9 are hydrogen atoms.
When only one R, such as R5 in the group of R1 to R5 in the general molecular structure is a polyol molecular unit (b) having n=2 and m=1; and all rest of Rs in the group of R1 to R9 are all hydrogen atoms, the following two chemical additives are obtained:
When one R, such as R5 is a polyol molecular unit (b) having n=2 and m=1; and one R, such as R2 is a six-member ring polyol; and all rest of Rs in the group of R1 to R14 are all hydrogen atoms, the following chemical additive is obtained:
The chemical additive comprises maltitol, lactitol, maltotritol, ribitol, D-sorbitol, mannitol, dulcitol, iditol, D-(−)-Fructose, sorbitan, sucrose, ribose, Inositol, glucose, D-arabinose, L-arabinose, D-mannose, L-mannose, meso-erythritol, beta-lactose, arabinose, and combinations thereof. The preferred chemical additives are maltitol, lactitol, maltotritol, D-sorbitol, mannitol, dulcitol, iditol, D-(−)-Fructose, sucrose, ribose, Inositol, glucose. D-(+)-mannose, beta-lactose, and combinations thereof. The more preferred chemical additives are maltitol, lactitol, maltotritol, D-sorbitol, mannitol, dulcitol, D-(−)-Fructose, beta-lactose, and combinations thereof.
In some embodiments, the CMP polishing compositions can be made into two or more parts and mixed at the point of use.
In another aspect, there is provided a method of chemical mechanical polishing (CMP) a substrate having at least one surface comprising silicon dioxide (such tetraethyl orthosilicate or TEOS) using the chemical mechanical polishing (CMP) composition described above.
In yet another aspect, there is provided a system of chemical mechanical polishing (CMP) a substrate having at least one surface comprising silicon dioxide using the chemical mechanical polishing (CMP) composition described above.
The substrate disclosed above can further comprises a silicon nitride (SiN) surface. The removal selectivity of SiO2: SiN is greater than 10, preferably greater than 20, and more preferably greater than 30.
This invention relates to the Chemical mechanical polishing (CMP) compositions, methods and systems for polishing oxide.
In the global planarization of patterned structures, reducing oxide trench dishing is a key factor to be considered. The lower trench oxide loss will prevent electrical current leaking between adjacent transistors. Non-uniform trench oxide loss across die or/and within Die will affect transistor performance and device fabrication yields. Severe trench oxide loss (high oxide trench dishing) will cause poor isolation of transistor resulting in device failure. Therefore, it is important to reduce trench oxide loss by reducing oxide trench dishing in CMP polishing compositions.
The CMP compositions comprise the unique combination of abrasive and the suitable chemical additives.
This invention provides a reduced oxide trench dishing and thus improved over polishing window stability by introducing chemical additives as oxide trench dishing reducing additives in the Chemical mechanical polishing (CMP) compositions at wide pH range including acidic, neutral and alkaline pH conditions.
The Chemical Mechanical Polishing (CMP) compositions provide high oxide film removal rates, low SiN film removal rates and high SiO2: SiN selectivity.
The Chemical Mechanical Polishing (CMP) composition also further provides excellent mean particle size and size distribution stability for the abrasive particles which is very important in maintaining robust CMP polishing performances with minimized polishing performance variations.
In one aspect, there is provided a CMP polishing composition comprises:
abrasive particles selected from the group consisting of ceria-coated inorganic metal oxide particles, ceria-coated organic polymer particles, and combinations thereof;
chemical additives as oxide trenching dishing reducers,
a solvent; and
optionally
biocide; and
pH adjuster;
wherein the composition has a pH of 2 to 12, preferably 3 to 10, and more preferably 4 to 9.
The ceria-coated inorganic metal oxide particles include, but are not limited to, ceria-coated colloidal silica, ceria-coated high purity colloidal silica, ceria-coated alumina, ceria-coated titania, ceria-coated zirconia, or any other ceria-coated inorganic metal oxide particles.
The ceria-coated organic polymer particles include, but are not limited to, ceria-coated polystyrene particles, ceria-coated polyurethane particle, ceria-coated polyacrylate particles, or any other ceria-coated organic polymer particles.
The average mean particle sizes or mean particle sizes (MPS) of abrasive particles are ranged from 2 to 1,000 nm, 5 to 500 nm, 15 to 400 nm or 25 to 250 nm. MPS refers to diameter of the particles and is measured using dynamic light scattering (DLS) technology.
The concentrations of abrasive particles range from 0.01 wt. % to 20 wt. %, the preferred concentrations range from 0.05 wt. % to 10 wt. %, the more preferred concentrations range from 0.1 wt. % to 5 wt. %.
The preferred abrasive particles are ceria-coated inorganic metal oxide particles; more preferred abrasive particles are ceria-coated silica particles.
The solvent includes but is not limited to deionized (DI) water, distilled water, and alcoholic organic solvents.
The preferred solvent is DI water.
The CMP slurry may contain biocide from 0.0001 wt. % to 0.05 wt. %; preferably from 0.0005 wt. % to 0.025 wt. %, and more preferably from 0.001 wt. % to 0.01 wt. %.
The biocide includes, but is not limited to, Kathon™, Kathon™ CG/ICP II, from Dupont/Dow Chemical Co. Bioban from Dupont/Dow Chemical Co. They have active ingredients of 5-chloro-2-methyl-4-isothiazolin-3-one or 2-methyl-4-isothiazolin-3-one.
The CMP slurry may contain a pH adjusting agent.
An acidic or basic pH adjusting agent can be used to adjust the polishing compositions to the optimized pH value.
The pH adjusting agents include, but are not limited to nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid, other inorganic or organic acids, and mixtures thereof.
pH adjusting agents also include the basic pH adjusting agents, such as sodium hydride, potassium hydroxide, ammonium hydroxide, tetraalkyl ammonium hydroxide, organic quaternary ammonium hydroxide compounds, organic amines, and other chemical reagents that can be used to adjust pH towards the more alkaline direction.
The CMP slurry contains 0 wt. % to 1 wt. %; preferably 0.01 wt. % to 0.5 wt. %; more preferably 0.1 wt. % to 0.25 wt. % pH adjusting agent.
The CMP slurry contains 0.01 wt. % to 20 wt. %, 0.025 wt. % to 10 wt. %, 0.05 wt. % to 5 wt. %, or 0.1 to 3.0 wt. % of the chemical additives as oxide trenching dishing and total defect count reducers.
The chemical additives as oxide trenching dishing reducers contain at least two or more, preferably four or more, more preferably six or more hydroxyl functional groups in their molecular structures.
In one embodiment, the chemical additive has a general molecular structure as shown below:
In the general molecular structure, n is selected from 2 to 5,000, from 3 to 12, preferably from 4 to 7.
R1, R2, and R3 can be the same or different atoms or functional groups.
Each of Rs in the group of R1 to R3 can be independently selected from the group consisting of hydrogen, alkyl, alkoxy, organic group with one or more hydroxyl groups, substituted organic sulfonic acid, substituted organic sulfonic acid salt, substituted organic carboxylic acid, substituted organic carboxylic acid salt, organic carboxylic ester, organic amine groups, and combinations thereof; wherein, at least two or more, preferably four of them are hydrogen atoms.
When R1, R2, and R3 are the same and are hydrogen atoms, the chemical additive bears multi hydroxyl functional groups.
The molecular structures of some examples of such chemical additives are listed below:
In another embodiment, the chemical additive has a structure shown below:
In this structure, one —CHO functional group is located at one end of the molecule as the terminal functional group; n is selected 2 to 5,000, from 3 to 12, preferably from 4 to 7.
R1 and R2 can be independently selected from the group consisting of hydrogen, alkyl, alkoxy, organic group with one or more hydroxyl groups, substituted organic sulfonic acid, substituted organic sulfonic acid salt, substituted organic carboxylic acid, substituted organic carboxylic acid salt, organic carboxylic ester, organic amine groups, and combinations thereof.
When R1 and R2 are all hydrogen atoms, and n=3, the chemical additive is D-arabinose or L-arabinose.
When R1, R2 and R3 are all hydrogen atoms, and n=4, the chemical additive is D-mannose or L-mannose.
In yet another embodiment, the chemical additive has a molecular structure selected from the group comprising of at least one (f), at least one (g), at least one (h) and combinations thereof:
In these general molecular structures; R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, and R14 can be the same or different atoms or functional groups.
They can be independently selected from the group consisting of hydrogen, alkyl, alkoxy, organic group with one or more hydroxyl groups, substituted organic sulfonic acid, substituted organic sulfonic acid salt, substituted organic carboxylic acid, substituted organic carboxylic acid salt, organic carboxylic ester, organic amine groups, and combinations thereof; wherein, at least two or more, preferably four or more of them are hydrogen atoms.
When R1, R2, R3 R4, R5, R6, R7 R8, R9, R10, R11, R12, R13, and R14 are all hydrogen atoms which provide the chemical additives bearing multi hydroxyl functional groups.
The molecular structures of some examples of such chemical additives are listed below:
Yet, in another embodiment, the chemical additives contain at least one six-member ring structure motif ether bonded with at least one polyol molecular unit containing multiple hydroxyl functional groups in the molecular unit structures or at least one polyol molecular unit containing multiple hydroxyl functional groups in the molecular unit structures and at least one six-member ring polyol. A polyol is an organic compound containing hydroxyl groups.
The chemical additives as oxide trenching dishing reducers contain at least two, at least four, or at least six hydroxyl functional groups in their molecular structures.
The general molecular structure for the chemical additives is shown in (a):
In one embodiment, at least one R in the group of R1 to R5 in the general molecular structure is a polyol molecular unit having a structure shown in (b):
wherein n and m can be the same or different. m or n is independently selected from 1 to 5, preferably from 1 to 4, more preferably from 1 to 3, and most preferably from 1 to 2; R6 to R9 can be the same or different atoms or functional groups; and
the rest of Rs in the group of R1 to R5 can be independently selected from the group consisting of hydrogen, alkyl, alkoxy, organic group with one or more hydroxyl groups, substituted organic sulfonic acid or salt, substituted organic carboxylic acid or salt, organic carboxylic ester, organic amine, and combinations thereof.
In another embodiment, at least one R in the group of R1 to R5 in the general molecular structure is a polyol molecular unit having a structure shown in (b); at least one R in the group of R1 to R5 in the general molecular structure is a six-member ring polyol as shown in (c):
wherein each of R10, R11, R12, R13 and R14 is independently selected from the group consisting of hydrogen, alkyl, alkoxy, organic group with one or more hydroxyl groups, substituted organic sulfonic acid or salt, substituted organic carboxylic acid or salt, organic carboxylic ester, organic amine, and combinations thereof;
and the rest of Rs in the group of R1 to R5 can be independently selected from the group consisting of hydrogen, alkyl, alkoxy, organic group with one or more hydroxyl groups, substituted organic sulfonic acid or salt, substituted organic carboxylic acid or salt, organic carboxylic ester, organic amine, and combinations thereof.
In the general molecular structure, at least two, preferably four, more preferably six of the Rs in the group of R1 to R9 are hydrogen atoms.
When only one R, such as R5 in the group of R1 to R5 in the general molecular structure is a polyol molecular unit (b) having n=2 and m=1; and all rest of Rs in the group of R1 to R9 are all hydrogen atoms, the following two chemical additives are obtained:
When one R, such as R5 is a polyol molecular unit (b) having n=2 and m=1; and one R, such as R2 is a six-member ring polyol; and all rest of Rs in the group of R1 to R14 are all hydrogen atoms, the following chemical additive is obtained:
The chemical additive comprises maltitol, lactitol, maltotritol, ribitol, D-sorbitol, mannitol, dulcitol, iditol, D-(−)-Fructose, sorbitan, sucrose, Inositol, glucose, D-arabinose, L-arabinose, D-mannose, L-mannose, meso-erythritol, ribose, beta-lactose, and combinations thereof. The preferred chemical additives are maltitol, lactitol, maltotritol, D-sorbitol, mannitol, dulcitol, iditol, D-(−)-Fructose, sucrose, ribose, Inositol, glucose. D-(+)-mannose, beta-lactose, and combinations thereof. The more preferred chemical additives are maltitol, lactitol, maltotritol, D-sorbitol, mannitol, dulcitol, D-(−)-Fructose, beta-lactose, and combinations thereof.
In some embodiments, the CMP polishing compositions can be made into two or more parts and mixed at the point of use.
In another aspect, there is provided a method of chemical mechanical polishing (CMP) a substrate having at least one surface comprising silicon dioxide using the chemical mechanical polishing (CMP) composition described above. The polished oxide films can be CVD oxide, PECVD oxide, High density oxide, Spin on oxide films, flowable CVD oxide film, carbon doped oxide film, or nitrogen doped oxide film.
The polished oxide films can be Chemical vapor deposition (CVD), Plasma Enhance CVD (PECVD), High Density Deposition CVD (HDP), or spin on oxide films.
The substrate disclosed above can further comprises a silicon nitride surface. The removal selectivity of SiO2: SiN is greater than 10, preferably greater than 20, and more preferably greater than 30.
Dishing performance of the CMP compositions can also be characterized by the ratio of oxide trench dishing rate (Å/min.) vs the blanket HDP film removal rate (Å/min.).
The smaller of this ratio is, the lower oxide trench dishing is. The CMP compositions having the ratio of 0.1, 0.08, 0.06, 0.05, 0.03, or 0.02 provide good oxide dishing performance.
In CMP polishing compositions, it is very important to keep abrasive particles stable to assure consistent desired CMP polishing performance.
When using the chemical additives in the CMP polishing compositions, these chemical additives can have some impacts on the stability of abrasive particles in the compositions.
For example, when maltitol, lactitol or their derivatives, are used as oxide trench reducing agents in polishing compositions, these chemical additives can have some impacts on the stability of ceria-coated inorganic oxide abrasives in the CMP polishing compositions.
Typically, the abrasive particle stability is tested by monitoring the mean particle size (MPS) (nm) and particle size distribution parameter D99 (nm) changes vs the times or at elevated temperatures.
Particle size distribution may be quantified as a weight percentage of particles that has a size lower than a specified size. For example, parameter D99 (nm) represents a particle size (diameter) where 99 wt. % of all the slurry particles would have particle diameter equal to or smaller than the D99 (nm). That is, D99 (nm) is a particle size that 99 wt. % of the particles fall on and under.
The smaller of MPS (nm) and D99 (nm) changes, the more stable of the abrasive particles are and thus the CMP polishing compositions are.
Particle size distribution can be measured by any suitable techniques such as imaging, dynamic light scattering, hydrodynamic fluid fractionation, disc centrifuge etc.
MPS (nm) and D99 (nm) are both measured by dynamic light scattering in this application.
CMP compositions providing abrasive particle stability have the changes for MPS (nm) and D99 (nm)≤6.0%, 5.0%, 3.0%, 2.0%, 1.0%, 0.5%, 0.3% or 0.1% for a shelf time of at least 30 days, 40 days, 50 days, 60 days, 70 days or 100 days at a temperature ranging from 20 to 60° C., 25 to 50° C.
The following non-limiting examples are presented to further illustrate the present invention.
In the examples presented below, CMP experiments were run using the procedures and experimental conditions given below.
Ceria-coated Silica: used as abrasive having a particle size of approximately 100 nanometers (nm); such ceria-coated silica particles can have a particle size of ranged from approximately 5 nanometers (nm) to 500 nanometers (nm);
Ceria-coated Silica particles (with varied sizes) were supplied by JGC Inc. in Japan.
Chemical additives, such as D-sorbitol, dulcitol, fructose, maltitol, lactitol and other chemical raw materials were supplied by Sigma-Aldrich, St. Louis, Mo.
TEOS: tetraethyl orthosilicate
Polishing Pad: Polishing pad, IC1010 and other pads were used during CMP, supplied by DOW, Inc.
Å or A: angstrom(s)—a unit of length
BP: back pressure, in psi units
CMP: chemical mechanical planarization=chemical mechanical polishing
CS: carrier speed
DF: Down force: pressure applied during CMP, units psi
min: minute(s)
ml: milliliter(s)
mV: millivolt(s)
psi: pounds per square inch
PS: platen rotational speed of polishing tool, in rpm (revolution(s) per minute)
SF: slurry flow, ml/min
Wt. %: weight percentage (of a listed component)
TEOS: SiN Selectivity: (removal rate of TEOS)/(removal rate of SiN)
HDP: high density plasma deposited TEOS
TEOS or HDP Removal Rates: Measured TEOS or HDP removal rate at a given down pressure. The down pressure of the CMP tool was 2.0, 3.0 or 4.0 psi in the examples listed above.
SiN Removal Rates: Measured SiN removal rate at a given down pressure. The down pressure of the CMP tool was 3.0 psi in the examples listed.
Films were measured with a ResMap CDE, model 168, manufactured by Creative Design Engineering, Inc, 20565 Alves Dr., Cupertino, Calif., 95014. The ResMap tool is a four-point probe sheet resistance tool. Forty-nine-point diameter scan at 5 mm edge exclusion for film was taken.
The CMP tool that was used is a 200 mm Mirra, or 300 mm Reflexion manufactured by Applied Materials, 3050 Boweres Avenue, Santa Clara, Calif., 95054. An IC1000 pad supplied by DOW, Inc, 451 Bellevue Rd., Newark, Del. 19713 was used on platen 1 for blanket and pattern wafer studies.
The IC1010 pad or other pad was broken in by conditioning the pad for 18 mins. At 7 lbs. down force on the conditioner. To qualify the tool settings and the pad break-in two tungsten monitors and two TEOS monitors were polished with Versum® STI2305 slurry, supplied by Versum Materials Inc. at baseline conditions.
Polishing experiments were conducted using PECVD or LECVD or HD TEOS wafers. These blanket wafers were purchased from Silicon Valley Microelectronics, 2985 Kifer Rd., Santa Clara, Calif. 95051.
In blanket wafer studies, oxide blanket wafers, and SiN blanket wafers were polished at baseline conditions. The tool baseline conditions were: table speed; 87 rpm, head speed: 93 rpm, membrane pressure; 3.0 psi, inter-tube pressure; 3.1 psi, retaining ring pressure; 5.1 psi, slurry flow; 200 ml/min.
The slurry was used in polishing experiments on patterned wafers (MIT860), supplied by SWK Associates, Inc. 2920 Scott Blvd. Santa Clara, Calif. 95054). These wafers were measured on the Veeco VX300 profiler/AFM instrument. The 3 different sized pitch structures were used for oxide dishing measurement. The wafer was measured at center, middle, and edge die positions.
TEOS: SiN Selectivity: (removal rate of TEOS)/(removal rate of SiN) obtained from the CMP polishing compositions were tunable.
In the following working examples, a polishing composition comprising 0.2 wt. % cerium-coated silica, a biocide ranging from 0.0001 wt. % to 0.05 wt. %, and deionized water was prepared as reference (ref.).
The polishing compositions were prepared with the reference (0.2 wt. % cerium-coated silica, a biocide ranging from 0.0001 wt. % to 0.05 wt. %, and deionized water) plus a chemical additive in 0.01 wt. % to 2.0 wt. %.
All examples, except pH condition examples the composition had a pH at 5.35.
pH adjusting agent used for acidic pH condition and alkaline pH condition were nitric acid and ammonium hydroxide respectively.
The working slurries has 0.15 wt. % chemical additives added to the reference slurry.
The effects of various selected chemical additives on the film removal rates and selectivity were observed.
The removal rates (RR at Å/min) for different films were tested. The test results were listed in Table 1.
As the results showed in Table 1, the slurries based on ceria-coated silica offered higher removal rate for TEOS.
As the results further showed in Table 1, the chemical additives D-sorbitol,
D-mannitol, D-mannose, and xylitol, except meso-erythritol suppressed SiN removal rates comparing with the Ref., while still afforded high TEOS and HDP film removal rates and provided high Oxide: SiN selectivity.
In Example 2, 0.2 wt. % ceria-coated silica abrasive based formulation without chemical additives was used as reference.
The chemical additives were used at 0.15 wt. % (0.15×) concentrations respectively with 0.2 wt. % ceria-coated silica as abrasives in the working slurries.
The test results were listed in Table 2. HDP RR (Å/min.) from Table 1 was also listed in Table 2.
Table 3 listed the ratio of oxide trench dishing rate (Å/min.) vs the blanket HDP film removal rate (Å/min.),
The test results were listed in Table 2. HDP RR (Å/min.) from Table 1 was also listed in Table 2.
Table 3 listed the ratio of oxide trench dishing rate (Å/min.) vs the blanket HDP film removal rate (Å/min.),
As the results shown in Tables 2 and 3, the addition of various chemical additives as oxide trench dishing reducer in polishing compositions showed different effects.
The polishing compositions using D-sorbitol and D-mannitol provided significant oxide trench dishing reductions on both 100 μm pitch and 200 μm pitch respectively, comparing to the reference.
The polishing composition using xylitol showed no impact on oxide trench dishing in polishing comparing to the reference. The polishing compositions using D-(+)-mannose or meso-erythritol had the oxide trench dishing worse than the reference.
The effects of chemical additives on the slopes of oxide trenching dishing vs over polishing removal amounts were listed in Table 4.
As the results shown in Table 4, the polishing composition using D-sorbitol or D-mannitol afforded much lower slope values of oxide trench dishing vs over polishing amounts on 100 μm and 200 μm features while comparing to the reference.
The other additives offered no dishing improvements comparing to the reference.
The effects of various selected chemical additives on the film removal rates (RR at Å/min) and selectivity were observed. These chemical additives were used at 0.1 wt. % concentrations respectively with 0.2 wt. % ceria-coated silica as abrasives.
The test results were listed in Table 5.
As the results showed in Table 5, these chemical additives D-sorbitol, D-(−)-Fructose, Maltitol and Dulcitol suppressed SiN removal rates while comparing with reference, and still afforded high TEOS and HDP film removal rates.
CMP composition having D-(−)-fructose suppressed removal of TEOS in addition of SiN, but still afforded high TEOS: SiN selectivity.
The effects of various selected chemical additives on the oxide trenching dishing vs over polishing times were observed.
The test results were listed in Table 6. HDP RR (Å/min.) from Table 5 was also listed in Table 6.
As the oxide trench dishing vs over polishing time results showed in Table 6, the CMP compositions with chemical additives afforded lower oxide trench dishing on 100 um pitch, and 200 um pitch, respectively. The compositions provided significant oxide trench dishing reductions comparing to the reference composition.
Table 7 listed the ratio of oxide trench dishing rate (Å/min.) vs the blanket HDP film removal rate (Å/min.),
As the results shown in Table 7, the addition of the chemical additives to the polishing compositions significantly reduced the ratio of trench dishing rate vs the blanket HDP film removal rates than the ratio obtained from the reference sample at pH 5.35.
The slopes of the various sized pitch dishing vs oxide over polishing amounts were listed in Table 8.
As the results of slopes of the various sized pitch dishing vs oxide over polishing amounts showed in Table 8, the chemical additives and ceria-coated silica abrasives based CMP polishing compositions afforded much lower slope values comparing to those slope values obtained from the reference.
In Example 4, the removal rates, and TEOS: SiN selectivity were tested tests were performed with CMP polishing compositions with chemical additives having different concentrations at pH 5.35.
The test results were listed in Table 9.
As the results showed in Table 9, when the concentration of D-sorbitol used in the compositions increased, similar TEOS removal rates were obtained, and HPD film removal rates were increased and TEOS: SiN selectivity were also increased slightly or significantly.
The effects on the oxide trenching dishing vs over polishing times from the selected chemical additive D-sorbitol concentrations on the various sized pitch features were tested.
The test results were listed in Table 10.
As the results showed in Table 10, all 3 tested CMP polishing compositions contained D-sorbitol with different concentrations gave low oxide trench dishing on both 100 μm pitch and 200 μm pitch.
Also, as the chemical additive D-sorbitol concentrations increased, the oxide trench dishing are further reduced.
As the results showed in Table 10, all 3 tested CMP polishing compositions contained D-sorbitol with different concentrations gave low oxide trench dishing on both 100 μm pitch and 200 μm pitch.
Also, as the chemical additive D-sorbitol concentrations increased, the oxide trench dishing are further reduced.
Table 11 listed the ratio of Trench Dishing Rate (A)/Blanket HDP RR (Å/min.)
from the compositions with different concentrations of D-Sorbitol.
As the results shown in Table 11, D-sorbitol used in the composition at pH 5.35, all significantly reduced the ratio of trench dishing rate vs the blanket HDP film removal rates across the different tested concentrations.
Therefore, D-sorbitol can be used as an effective oxide trench dishing reducer in the wide concentration range.
The slopes of the various sized pitch dishing vs oxide over polishing amounts were tested and the results were listed in Table 12.
As the results of slopes of the various sized pitch dishing vs oxide over polishing amounts showed in Table 12, different concentrations of D-sorbitol in CMP polishing compositions all afforded similar slope values comparing to the reference sample.
Also, as the D-sorbitol concentration increased, the slopes of the various sized pitch dishing vs oxide over polishing while at over polishing time at zero seconds gradually decreased.
In Example 5, the tests were performed with CMP polishing compositions having different pH values.
The composition composed of 0.2 wt. % ceria-coated silica as abrasives and 0.1 wt. % D-sorbitol as chemical additive was tested at three different pH conditions.
The removal rates (RR at Å/min) for different films were tested. The test results were listed in Table 13.
As the results showed in Table 10, the compositions showed a consistent performance by offering high TEOS and HDP film removal rates, low SiN removal rates, and high TEOS: SiN selectivity in acidic, neutral or alkaline pH conditions..
The test results on the effects of pH conditions using the CMP polish compositions on oxide trench dishing vs over polishing times were performed.
The results were listed in Table 14.
As the results showed in Table 14, similar oxide trenching dishing vs over polishing times and HDP film removal rates were obtained for the same concentration of ceria-coated silica as abrasives and D-sorbitol as oxide trenching dishing reducing agent at 3 different pH conditions.
Table 15 showed the results of the ratio of Trench Dishing Rate (A)/Blanket HDP RR (Å/min.),
As the results shown in Table 15, the addition of the chemical additives, D-sorbitol, used as oxide trench dishing reducer in polishing compositions at different pH conditions, showed significantly reduction of the ratio which indicated that D-sorbitol can be used as a very effective oxide trench dishing reducing agent at wide pH window.
In Example 6, the effects of various selected chemical additives from afore listed several types of chemical additives on the film removal rates and selectivity were observed.
The same molar concentrations of all tested chemical additives at 8.132 mM was used respectively.
All examples, except examples for the pH condition test had a pH at 5.35.
For the examples used in the pH condition test, pH adjusting agent was used for acidic pH condition and alkaline pH condition were nitric acid and ammonium hydroxide respectively.
The removal rates (RR at Å/min) and removal selectivity for different films were tested. The test results were listed in Table 16.
As the results showed in Table 16, these chemical additives, when used at 8.132 mM concentrations in the polishing compositions afforded similar TEOS film removal rates, HDP film removal rates, slightly or significantly suppressed SiN removal rates comparing with the reference.
The Oxide: SiN selectivity was fluctuating from slightly increased (arabinose, myo-inositol) to significantly increased (maltitol, ribose and beta-lactose). Among these tested chemical, maltitol showed as the most efficient SiN removal rate suppressing chemical additive, and ribose and beta-lactose also showed as quite efficient SiN removal rate suppressing additives.
The following chemical additives, maltitol, D-sorbitol, lactitol, ribose, and beta-lactose were used in the polishing compositions with 0.2 wt. % ceria-coated silica abrasives at pH 5.35 to have conducted polishing tests on polishing oxide patterned wafers. The chemical additives were used at 0.15 wt. % in the compositions.
The effects of various chemical additives on the film removal rates and selectivity were observed.
The test results were listed in Table 17.
As the results showed in Table 17, all compositions afforded similar high TEOS film removal rates, increased HDP film high removal rates, significantly suppressed SiN removal rates, significantly increased Oxide: SiN selectivity comparing with the reference sample.
The effects of various chemical additives on the oxide trenching dishing vs over polishing times were observed. These chemical additives were used at 0.15 wt. % (0.15×) concentrations respectively with 0.2 wt. % ceria-coated silica as abrasive, and with all formulations at pH 5.35.
The test results were listed in Table 18.
As the oxide trench dishing vs over polishing time results showed in Table 18, all of these chemical additives, when used with ceria-coated silica abrasives in the CMP polishing compositions, afforded largely reduced oxide trench dishing vs over polishing times at 60 seconds or 120 seconds respectively on 100 μm pitch and 200 μm pitch features, and provided significant oxide trench dishing reductions comparing to the reference.
Table 19 showed the results of the ratio of Trench Dishing Rate (A)/Blanket HDP RR (Å/min.),
As the results shown in Table 19, all tested polishing compositions using chemical additives showed significantly reduction of the ratio of trench dishing rate vs the blanket HDP film removal rates which indicated that all these chemical additives can be used as very effective oxide trench dishing reducing agents in the invented CMP polishing compositions.
The polishing compositions were prepared with the reference (0.2 wt. % ceria-coated silica, a biocide ranging from 0.0001 wt. % to 0.05 wt. %, and deionized water) and maltitol or lactitol were used at 0.28 wt. %.
All example compositions had a pH at 5.35.
The removal rates (RR at Å/min) for different films were tested. The effects of two selected chemical additives, maltitol and lactitol on the film removal rates and selectivity were observed.
The test results were listed in Table 20.
As the results shown in Table 20, the addition of the chemical additives, maltitol or lactitol, in the polishing compositions, significantly suppressed SiN removal rates while still afforded high TEOS and HDP film removal rates, thus, significantly increased Oxide: SiN film polishing selectivity.
The example compositions in Example 8 were used in this Example.
Oxide trenching dishing for without/or with different over polishing times were tested. The effects of maltitol or lactitol on the oxide trenching dishing vs over polishing times were observed.
The test results were listed in Table 21.
As the results shown in Table 21, the polishing compositions with the addition of the chemical additives, maltitol or lactitol, afforded low oxide trench dishing on 100 μm pitch, and 200 μm pitch respectively when 60 second or 120 second over polishing times were applied.
The compositions provided significant oxide trench dishing reductions comparing to the reference composition which did not have the chemical additives, maltitol or lactitol.
Table 22 showed the results of the ratio of Trench Dishing Rate (A)/Blanket HDP RR (Å/min.),
As the results shown in Table 22, the addition of either maltitol or lactitol as oxide trench dishing reducer in polishing compositions significantly reduced the ratio of trench dishing rate vs the blanket HDP film removal rates, the lower of this ratio is, the lower of oxide trench dishing is.
The slopes of oxide trench dishing vs the OP removal amount was showed in Table 23.
The results listed in Table 23 indicated that the compositions with chemical additives, maltitol or lactitol provided lower slopes which indicated good over polishing window for maintaining low oxide trench dishing even more oxide film removed in over polishing steps.
As showing in Table 23, these chemical additives, maltitol or lactitol, and ceria-coated silica based CMP polishing compositions again showed much lower slope values comparing to those slope values obtained for the ceria-coated silica abrasive based reference sample.
In Example 10, the trench oxide loss rates were compared for the polishing compositions using maltitol or lactitol and reference as listed in Table 24.
As the results shown in Table 24, the addition of maltitol or lactitol as oxide trench dishing reducing agent into the polishing compositions, the trench loss rates were significantly reduced vs the reference sample without using any chemical additives.
The compositions were prepared as shown in Table 19.
The compositions used of 0.2 wt. % ceria-coated silica as abrasives, 0.28 wt. % lactitol as chemical additive, biocide, DI water, and a pH adjusting agent to provide different pH conditions.
The removal rates (RR at Å/min) for different films were tested. The effects of pH conditions on the film removal rates and selectivity were observed.
The test results were listed in Table 25.
As the results shown in Table 25, the addition of lactitol as oxide trench dishing reducing agent into the polishing compositions at three different pH conditions, (acidic, neutral or alkaline) gave similar TEOS and HDP film removal rates, very effectively suppressed SiN film removal rates, and yielded much higher TEOS: SiN selectivity than the reference sample without using lactitol as chemical additive.
Oxide trenching dishing for without/or with lactitol as chemical additive over polishing times were tested.
The effects of lactitol containing polishing composition at different pH conditions on the oxide trenching dishing vs over polishing times were observed.
The test results were listed in Table 26.
As the results shown in Table 26, the polishing compositions with the addition of lactitol, at different pH conditions afforded low oxide trench dishing on 100 μm pitch, and 200 μm pitch respectively when 60 second or 120 second over polishing times were applied.
The compositions with lactitol as oxide trench dishing reducing agent provided significant oxide trench dishing reductions comparing to the reference polishing composition which did not have the chemical additive, lactitol.
Table 27 depicted the ratio of Trench Dishing Rate (A)/Blanket HDP RR (Å/min.) at Different pH.
As the results shown in Table 27, the addition of lactitol as oxide trench dishing reducer in polishing composition significantly reduced the ratio of trench dishing rate vs the blanket HDP film removal rates at different pH conditions than that ratio obtained for reference sample at pH 5.35.
The slopes of oxide trench dishing vs the OP removal amount at different pH conditions was showed in Table 28.
The results listed in Table 28 indicated that the compositions with chemical additive lactitol at different pH conditions provided lower slopes of trench dishing vs the over polishing removal amounts which indicated good over polishing window for maintaining low oxide trench dishing even more oxide film removed in over polishing steps.
As showing in Table 28, lactitol and ceria-coated silica based CMP polishing compositions again showed much lower slope values at different pH conditions comparing to those slope values obtained for the ceria-coated silica abrasive based reference sample at pH 5.35.
In Example 11, the trench oxide loss rates were compared for the polishing compositions using lactitol at different pH conditions or without using lactitol at pH 5.35 and listed in Table 29.
As the results shown in Table 29, the addition of lactitol as oxide trench dishing reducing agent into the polishing compositions at different pH conditions, the trench loss rates were significantly reduced vs the reference sample without using lactitol as chemical additive.
The polishing test results obtained at different pH conditions using lactitol as oxide trench dishing reducer proved that the CMP polishing compositions can be used in wide pH range including acidic, neutral or alkaline pH conditions.
When using the suitable chemical additives, such as maltitol or lactitol or their derivatives, as oxide trench reducing agents in polishing compositions, these chemical additives can have some impacts on the stability of ceria-coated inorganic oxide abrasives in the CMP polishing compositions. In CMP polishing compositions, it is very important to have good abrasive particle stability to assure constant and desirable CMP polishing performances.
Typically, the abrasive particle stability is tested through monitoring the MPS (nm) (=mean particle size) and D99 (nm) changes vs the times or at elevated temperatures. The smaller of MPS (nm) and D99 (nm) changes, the more stable of the invented polishing compositions are.
In this example, the stability of ceria-coated silica abrasive particles in the compositions having chemical additives was monitored by measuring the change of the mean particles size and the change of particle size distribution D99.
The testing samples were made using 0.2 wt. % or other wt. % ceria-coated silica abrasive; very low concentration of biocide; 0.15 wt. % maltitol, 0.15 wt. % lactitol or 0.0787 wt. % Myo-inositol as oxide trench dishing reducer; and with pH adjusted to 5.35.
The abrasive stability tests on the polishing compositions were carried out at 50° C. for at least 10 days or more.
The MPS (nm) or D99 (nm) of the tested polishing compositions were measured using DLS technology (DLS=dynamic light scattering).
The stability test results of the used ceria-coated silica abrasives with the chemical additives were listed in Table 30.
By day 4 at 50° C., 0.2 wt. % ceria-coated silica particles had MPS changes of 0.23%, 0.34% and 0.39% in the compositions having 0.15 wt. % maltitol, 0.15 wt. lactitol and 0.0787 wt. % myo-inositol respectively.
0.2 wt. % ceria-coated silica particles in the composition having 0.15 wt. maltitol had a mean particle size change of less than 1.9% by day 18 at 50° C.
0.2 wt. % ceria-coated silica particles in the composition having 0.0787 wt. % myo-inositol had a mean particle size change of less than 0.83% by day 11 at 50° C.
0.2 wt. % ceria-coated silica particles in the composition having 0.15 wt. % lactitol had a mean particle size change of less than 1.3% by day 32 at 50° C.
More stability test were listed in Table 31.
0.2 wt. % ceria-coated silica particles in the composition having 0.15 wt. % maltitol had a mean particle size and D99 changes of less than 8.34×10−4 and 0.63 respectively by day 62 at 50° C.
Furthermore, the particle stability tests were also conducted at 50° C. on polishing compositions comprised more concentrated ceria-coated silica abrasives (more than 0.2 wt. %) and more concentrated maltitol (more than 0.15 wt. %) as oxide trench dishing reducer.
The test results were listed in Table 32.
Data showed that 0.8 wt. % of the ceria-coated silica particles had MPS and D99 changes of less than 0.41% and less than 0.23% respectively by day 42 at 50° C. in the composition having 0.6 wt. % of maltitol respectively.
Data also showed that 0.8 wt. % of the ceria-coated silica particles had MPS and D99 changes of less than 0.41% and less than 0.23% respectively by day 42 at 50° C. in the composition having 0.6 wt. % of maltitol respectively.
1.6 wt. % of the ceria-coated silica particles had MPS and D99 changes of less than 1.2% and less than 1.6% respectively by day 42 at 50° C. in the composition having 1.2 wt. % of maltitol respectively.
2.4 wt. % of the ceria-coated silica particles had MPS and D99 changes of less than 0.33% and less than 0.23% respectively by day 42 at 50° C. in the composition having 1.8 wt. % of maltitol respectively.
As the results shown in Table 30 to 32, when maltitol, lactitol or Myo-inositol used as oxide trench dishing reducer with ceria-coated silica particles as abrasives, the polishing compositions showed very good particle size stability of MPS (nm) and D99 (nm) even at elevated testing temperatures.
The polishing compositions comprised of ceria-coated colloidal silica abrasives and more concentrated maltitol as oxide trench dishing reducer all showed very good particle size stability of MPS (nm) and D99 (nm) at elevated temperatures.
Another key benefit of using the present invented CMP polishing compositions is the reduced total defect counts through and post-polishing which is resulted in by using the ceria-coated colloidal silica composite particles as abrasives instead of using calcined ceria particle as abrasives.
The following three polishing compositions were prepared for defects testing. The first sample was made using 0.5 wt. % calcined ceria abrasives, 0.05 wt. % polyacrylate salt and low concentration of biocide; the second sample was made using 0.2 wt. % ceria-coated silica abrasives, 0.28 wt. % maltitol and low concentration of biocide; the third sample was made using 0.2 wt. % ceria-coated silica abrasives, 0.28 wt. % lactitol and low concentration of biocide. In order to obtain similar dielectric film removal rates to be compared, higher concentration of calcinated ceria abrasive was used in sample 1.
All three formulations have pH valued at 5.35.
The total defect counts on polished TEOS and SiN wafers were compared by using three afore listed polishing compositions. The total defect count results were listed in Table 33.
As the total defect count results shown in Table 33, the polishing compositions using ceria-coated silica particles as abrasives and either of maltitol or lactitol as trench dishing reducing agent afforded significantly lower total defect counts on the polished TEOS and SiN wafers than the total defect counts obtained using the polishing composition comprised of calcined ceria abrasives and polyacrylate salt as chemical additive.
The following four polishing compositions were prepared for the defects testing.
The first two polishing compositions used calcined ceria abrasives, 0.28 wt. % maltitol or 0.28 wt. % lactitol as oxide trenching dishing reducing agent and low concentration of biocide; the other two polishing compositions were made using ceria-coated silica abrasives, 0.28 wt. % maltitol or 0.28 wt. % lactitol as oxide trenching dishing reducing agent and low concentration of biocide. All four formulations have pH valued at 5.35.
All chemical additives used at the same wt. %, but different types of abrasives were used, e.g., calcined ceria vs ceria-coated silica particles as abrasives.
The effects of different types of abrasives on the film removal rates and TEOS: SiN selectivity were observed and the results were listed in table 34.
As the results shown in Table 34, the polishing compositions that used ceria-coated silica as abrasives did afford much higher TEOS and HDP film removal rates than those film removal rates obtained from the polishing compositions which used calcined ceria as abrasives.
The normalized total defect counts on polished TEOS and SiN wafers were compared by using four afore listed polishing compositions. The normalized total defect count results were listed in Table 35.
As the normalized total defect count results shown in Table 35, the polishing compositions using ceria-coated silica particles as abrasives and either maltitol or lactitol as trench dishing reducing agent afforded significantly lower normalized total defect counts on the polished TEOS and SiN wafers than the normalized total defect counts obtained using the polishing composition comprised of calcined ceria abrasives, and either maltitol or lactitol as oxide trench dishing reducing chemical additive.
The embodiments of this invention listed above, including the working example, are exemplary of numerous embodiments that may be made of this invention. It is contemplated that numerous other configurations of the process may be used, and the materials used in the process may be elected from numerous materials other than those specifically disclosed.
This application claims the benefit of priority under 35 U.S.C. § 119(e) to earlier filed U.S. patent applications Ser. Nos. 62/692,633, and 62/692,639 filed on Jun. 29, 2018, which are entirely incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62692633 | Jun 2018 | US | |
| 62692639 | Jun 2018 | US |
