Cmp formulations and methods for polishing polysilicon films

Abstract

The CMP composition of the present invention comprises silica particles as an abrasive, a first chemical additive comprising a quaternary amine, a second chemical additive comprising a sulfonic acid group, a water soluble solvent, and optionally a biocide and a pH adjuster; wherein the pH of the composition is from 8 to 12. The CMP composition has a high polysilicon removal rate and a high selectivity of the polysilicon removal rate over the silicon nitride removal rate.

Description

Cross-reference to related applications

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 601,119, filed November 20, 2023, the entire contents of which are incorporated herein by reference. Background Technology

[0002] This disclosure relates to chemical mechanical planarization (CMP) compositions that can be used for polishing films containing polycrystalline silicon.

[0003] In semiconductor device manufacturing, hard masks are used to etch deep, high aspect ratio (HAR) features that conventional photoresists cannot withstand. For advanced logic and memory, including DRAM and vertical NAND, hard masks require extremely high etch selectivity, low stress, and good mechanical strength. They also need to be removable upon completion of etching. For advanced devices with extremely high aspect ratios, the required hard mask thickness is considerable. Therefore, CMP (Catalytic Motion Processing) is considered a suitable technique for removing hard masks.

[0004] Polycrystalline silicon (poly-Si) films are used in a variety of integrated circuit (IC) applications. Components containing polycrystalline silicon films can be gate electrodes, damascene interconnects, and structural components.

[0005] Polycrystalline silicon films can be deposited on stop layers comprising films such as silicon oxide (SiO2) or silicon nitride (SiN). Selectivity is characteristically expressed as the ratio of the polishing or removal rate of the polycrystalline silicon film to the polishing or removal rate of the stop layer. For some applications, high selectivity of the polycrystalline silicon film relative to the stop layer film is required to protect the stop layer. Summary of the Invention

[0006] This disclosure provides a CMP polishing composition for polishing films containing polycrystalline silicon.

[0007] In a first principal aspect, a chemical mechanical polishing composition is provided. The chemical mechanical polishing composition comprises: an abrasive containing silica particles; 0.01 wt% to 10.0 wt%, preferably 0.025 wt% to 1.0 wt%, or most preferably 0.05 wt% to 0.5 wt% of a first chemical additive, wherein the first chemical additive comprises molecules containing a quaternary ammonium compound; 0.005 wt% to 1.0 wt%, or preferably 0.01 wt% to 0.5 wt% of a second chemical additive, wherein the second chemical additive comprises a sulfonic acid compound; a water-soluble solvent; and optionally a biocide; and a pH adjuster; wherein the pH of the chemical mechanical polishing composition is preferably 8 to 12, more preferably 9 to 11, and most preferably 9.5 to 10.5.

[0008] In a further aspect of the first principal aspect, the quaternary ammonium compound is selected from ethyltrimethylammonium hydroxide (ETMAH), ethyltrimethylammonium bromide, ethyltrimethylammonium chloride, benzyl ammonium hydroxide, benzalkonium bromide, benzalkonium chloride, hexadecyltrimethylammonium hydroxide, hexadecyltrimethylammonium bromide (CTAB), hexadecyltrimethylammonium chloride, lauryltrimethylammonium hydroxide, lauryltrimethylammonium bromide, lauryltrimethylammonium chloride (LTAC), stearylammonium hydroxide, stearylammonium bromide, stearylammonium chloride, hexadecylpyridinium hydroxide, hexadecylpyridinium bromide, hexadecylpyridinium chloride (cephalopyridinium chloride), poly(dimethyldiallylammonium hydroxide), poly(dimethyldiallylammonium bromide), poly(dimethyldiallylammonium chloride) (PDMDAAC), trimethylstearylammonium hydroxide, trimethylstearylammonium bromide, trimethyl Stearyl ammonium chloride, dimethyl di-octadecyl ammonium hydroxide, dimethyl di-octadecyl ammonium bromide, dimethyl di-octadecyl ammonium chloride, tetraalkyl ammonium hydroxide, tetraalkyl ammonium bromide, tetraalkyl ammonium chloride, tetramethyl ammonium hydroxide (TMAH), tetramethyl ammonium bromide, tetramethyl ammonium chloride, tetraethyl ammonium hydroxide, tetraethyl ammonium bromide, tetraethyl ammonium chloride, tetrapropyl ammonium hydroxide, tetrapropyl ammonium bromide, tetrapropyl ammonium chloride, tetrabutyl ammonium hydroxide, tetrabutyl ammonium bromide, tetrabutyl ammonium chloride, ethyltrimethyl ammonium hydroxide, ethyltrimethyl ammonium bromide, ethyltrimethyl ammonium chloride, diethyldimethyl ammonium hydroxide, diethyldimethyl ammonium bromide, diethyldimethyl ammonium chloride, methyltriethyl ammonium hydroxide, methyltriethyl ammonium bromide, methyltriethyl ammonium chloride, choline hydroxide, choline bromide, choline chloride, choline bicarbonate, choline tartrate, and other choline salts.

[0009] In a further aspect of the first main aspect, the second chemical additive is selected from methanesulfonic acid (MSA), benzenesulfonic acid (BSA), toluenesulfonic acid, p-toluenesulfonic acid, 2-naphthalenesulfonic acid, naphthalene-1-sulfonic acid, dodecylbenzenesulfonic acid (DDBSA), camphorsulfonic acid, ligninsulfonic acid, and poly(styrenesulfonic acid) (PSSA), ethanedisulfonic acid, naphthalene-2-sulfonic acid, and naphthalenedisulfonic acid.

[0010] In a further aspect of the first principal aspect, the first chemical additive comprises ethyltrimethylammonium hydroxide. In a further aspect of the first principal aspect, the second chemical additive comprises benzenesulfonic acid. In a further aspect of the first principal aspect, it further comprises an amino acid.

[0011] In a further aspect of the first main aspect, the amino acid is glycine.

[0012] In a further aspect of the first principal aspect, the first chemical additive comprises ethyltrimethylammonium hydroxide, and the second chemical additive comprises benzenesulfonic acid.

[0013] In a further aspect of the first main aspect, the ratio of the first chemical additive to the second chemical additive is about 4:1 to about 1:4, preferably about 3:1 to about 1:3, and most preferably about 2:1 to about 1:2.

[0014] In a second principal aspect, a method is provided for chemical mechanical polishing (CMP) of a semiconductor substrate having at least one surface comprising a film containing polycrystalline silicon and silicon nitride. The method includes: providing a semiconductor substrate; providing a polishing pad; providing a chemical mechanical polishing (CMP) composition according to any one of claims 1 to 9; contacting a surface of the semiconductor substrate with the polishing pad and the chemical mechanical polishing composition; and polishing the at least one surface.

[0015] In a further aspect of the second main aspect, the selectivity of the polysilicon removal rate relative to the silicon nitride removal rate is greater than about 50, preferably greater than about 70, and more preferably greater than about 80.

[0016] In a further aspect of the second main aspect, the removal rate of polycrystalline silicon is greater than about 5000 Å / min, preferably greater than about 6000 Å / min, and most preferably greater than about 6500 Å / min.

[0017] In a third principal aspect, a chemical mechanical polishing (CMP) system is provided for a semiconductor substrate having at least one surface comprising a polysilicon-containing film. The system comprises: a. a semiconductor substrate; b. a chemical mechanical polishing (CMP) composition according to any one of claims 1 to 9; and c. a polishing pad; wherein the at least one polysilicon-containing surface is in contact with the polishing pad and the chemical mechanical polishing composition.

[0018] In a further aspect of the third main aspect, the semiconductor substrate further includes a silicon oxide film, wherein the silicon oxide film is selected from chemical vapor deposition (CVD), plasma-enhanced CVD (PECVD), high-density deposition CVD (HDP), or spin-coated silicon oxide film.

[0019] In a further aspect of the third main aspect, the semiconductor substrate also includes a silicon nitride film.

[0020] In a further aspect of the third main aspect, the selectivity of the polysilicon removal rate relative to the silicon nitride removal rate is greater than about 50, preferably greater than about 70, and more preferably greater than about 80. Attached Figure Description

[0021] Figure 1 Graphs showing the removal rate and selectivity of the CMP composition of Example 1 of this disclosure are provided; Figure 2 Graphs showing the removal rate and selectivity of the CMP composition of Example 2 of this disclosure are provided; and Figure 3 A graph showing the silicon nitride removal rate of the CMP composition of Example 2 of this disclosure is provided.

[0022] Detailed Implementation Plan Semiconductor device manufacturing involves processes that form finely patterned films on a substrate. Creating a patterned film involves several deposition, etching, and polishing (CMP) steps. Hard masks are typically used to protect the underlying film during the etching process. CMP is one of the processes used to remove the hard mask after the etching process is complete.

[0023] Polycrystalline silicon-based films are widely used due to their excellent chemical and mechanical properties.

[0024] Polished polycrystalline silicon films may contain more than 50% polycrystalline silicon by atomic percentage. Polished polycrystalline silicon films may also contain other elements, such as, but not limited to, silicon, germanium, carbon, nitrogen, phosphorus, oxygen, and hydrogen.

[0025] This disclosure relates to chemical mechanical polishing (CMP) compositions for polishing polycrystalline silicon films.

[0026] More specifically, the disclosed chemical mechanical polishing (CMP) composition for polycrystalline silicon films has a unique combination of silica particles and suitable chemical additives for improving the removal rate of polycrystalline silicon films and for reducing the removal rate of silicon nitride films.

[0027] The first type of chemical additive is a polysilicon removal rate accelerator.

[0028] Preferably, the first chemical additive comprises molecules containing quaternary ammonium compounds.

[0029] Preferably, the quaternary ammonium compound is selected from ethyltrimethylammonium hydroxide (ETMAH), ethyltrimethylammonium bromide, ethyltrimethylammonium chloride, benzyl ammonium hydroxide, benzalkonium bromide, benzalkonium chloride, hexadecyltrimethylammonium hydroxide, hexadecyltrimethylammonium bromide (CTAB), hexadecyltrimethylammonium chloride, lauryltrimethylammonium hydroxide, lauryltrimethylammonium bromide, lauryltrimethylammonium chloride (LTAC), stearylammonium hydroxide, stearylammonium bromide, stearylammonium chloride, hexadecylpyridinium hydroxide, hexadecylpyridinium bromide, hexadecylpyridinium chloride (cephalopyridinium chloride), poly(diallyldimethylammonium hydroxide), poly(diallyldimethylammonium bromide), poly(diallyldimethylammonium chloride) (PDMDAAC), trimethylstearylammonium hydroxide, trimethylstearylammonium bromide, trimethylstearyl chloride Ammonium, dimethyl di-octadecyl ammonium hydroxide, dimethyl di-octadecyl ammonium bromide, dimethyl di-octadecyl ammonium chloride, tetraalkyl ammonium hydroxide, tetraalkyl ammonium bromide, tetraalkyl ammonium chloride, tetramethyl ammonium hydroxide (TMAH), tetramethyl ammonium bromide, tetramethyl ammonium chloride, tetraethyl ammonium hydroxide, tetraethyl ammonium bromide, tetraethyl ammonium chloride, tetrapropyl ammonium hydroxide, tetrapropyl ammonium bromide, tetrapropyl ammonium chloride, tetrabutyl ammonium hydroxide, tetrabutyl ammonium bromide, tetrabutyl ammonium chloride, ethyltrimethyl ammonium hydroxide, ethyltrimethyl ammonium bromide, ethyltrimethyl ammonium chloride, diethyldimethyl ammonium hydroxide, diethyldimethyl ammonium bromide, diethyldimethyl ammonium chloride, methyltriethyl ammonium hydroxide, methyltriethyl ammonium bromide, methyltriethyl ammonium chloride, choline hydroxide, choline bromide, choline chloride, choline bicarbonate, choline tartrate, and other choline salts.

[0030] More preferably, the CMP composition contains 0.01% to 10.0% by weight, preferably 0.025% to 1.0% by weight, or most preferably 0.05% to 0.5% by weight of a first chemical additive.

[0031] Preferably, the first chemical additive comprises ethyltrimethylammonium hydroxide.

[0032] The second type of chemical additive is a silicon nitride removal rate inhibitor. Preferably, the second chemical additive contains a sulfonic acid compound.

[0033] Preferably, the sulfonic acid compound is selected from methanesulfonic acid (MSA), benzenesulfonic acid (BSA), toluenesulfonic acid, p-toluenesulfonic acid, 2-naphthalenesulfonic acid, naphthalene-1-sulfonic acid, dodecylbenzenesulfonic acid (DDBSA), camphorsulfonic acid, ligninsulfonic acid, and poly(styrenesulfonic acid) (PSSA), ethanedisulfonic acid, naphthalene-2-sulfonic acid, and naphthalenedisulfonic acid.

[0034] More preferably, the CMP composition contains 0.005% to 1.0% by weight, or preferably 0.01% to 0.5% by weight, of a second chemical additive.

[0035] Preferably, the second chemical additive comprises benzenesulfonic acid.

[0036] The silica particles disclosed herein have a particle size range of 5 nm to 1,000 nm (as measured by dynamic light scattering (DLS)). A preferred average particle size range is 20 nm to 500 nm, and a more preferred average particle size range is 20 nm to 100 nm.

[0037] Silica particles can be modified to provide a positive surface charge using any suitable method. One approach is to incorporate a cationic compound into the formulation itself. Alternatively, the silica particles can be modified to generate a positive surface Z-potential before being incorporated into the slurry formulation.

[0038] Examples of suitable methods for modifying the surface charge of particles include, but are not limited to, treating particles or particle precursors with nitrogen or phosphorus compounds. Several such methods can be found in publications such as U.S. Patent Nos. 9,499,721, 2003,020,9522, 2005,007,9718, and 2009,008,1927. The treated particles may contain nitrogen or phosphorus compounds on their surface, either internally to the outer surface of the particles or as a shell formed on the core particles. Aminosilane compounds are the most preferred nitrogen-containing compounds. Such aminosilane compounds may include primary aminosilanes, secondary aminosilanes, tertiary aminosilanes, quaternary aminosilanes, and polypody (e.g., bipody) aminosilanes. Aminosilane compounds may include substantially any suitable aminosilane, such as aminosilanes containing propyl groups or aminosilane compounds containing propylamine. Suitable examples of aminosilanes may include bis(2-hydroxyethyl)-3-aminopropyltrialkoxysilane, diethylaminomethyltrialkoxysilane, (N,N-diethyl-3-aminopropyl)trialkoxysilane, 3-(N-styrylmethyl-2-aminoethylaminopropyl)trialkoxysilane, aminopropyltrialkoxysilane, (2-N-benzylaminoethyl)-3-aminopropyltrialkoxysilane, trialkoxysilylpropyl-N,N,N-trimethylammonium, N-(trialkoxysilylethyl)benzyl-N,N,N-trimethylammonium, (bis(methyldialkoxysilylpropyl)-N-methylamine, bis(trialkoxysilylpropyl)urea, bis(3-(trialkoxysilylpropyl)... (Syryl)propyl)-ethylenediamine, bis(trialkoxysilylpropyl)amine, bis(trialkoxysilylpropyl)amine, 3-aminopropyltrialkoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldialkoxysilane, N-(2-aminoethyl)-3-aminopropyltrialkoxysilane, 3-aminopropylmethyldialkoxysilane, 3-aminopropyltrialkoxysilane, (N-trialkoxysilylpropyl)polyethyleneimine, trialkoxysilylpropyldiethylenetriamine, N-phenyl-3-aminopropyltrialkoxysilane, N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrialkoxysilane, 4-aminobutyltrialkoxysilane, and mixtures thereof.

[0039] Silica can be any of precipitated silica, fumed silica, fumed silica produced by pyrolysis, colloidal silica, high-purity colloidal silica, silica doped with one or more additives, or any other silica-based compound. In alternative embodiments, silica can be produced, for example, by a process selected from sol-gel processes, hydrothermal processes, plasma processes, fumigation processes, precipitation processes, and any combination thereof. Silica can also be modified by incorporating various metals or metalloid compounds into the bulk or surface of the particles.

[0040] The particles can have various shapes, including but not limited to spherical, cocoon-shaped, or chain-like structures. A cocoon-shaped particle shape is preferred. Cocoon-shaped particles are characterized by an aggregation ratio, which is the ratio of the average particle size measured by DLS to the primary particle size calculated based on the specific surface area (assuming non-porous spherical particles). The preferred aggregation ratio of cocoon-shaped particles is >1.7, or more preferably between 1.7 and 2.3.

[0041] The concentration of these silica particles ranges from 0.01 wt% to 20 wt%, preferably from 0.05 wt% to 2 wt%, and more preferably from 0.1 wt% to 1 wt%.

[0042] Water-soluble solvents include, but are not limited to, deionized (DI) water, distilled water, and alcoholic organic solvents. DI water is the preferred water-soluble solvent.

[0043] The polycrystalline silicon polishing CMP composition may contain 0.0001% to 0.05% by weight; preferably 0.0005% to 0.025% by weight, more preferably 0.001% to 0.01% by weight of a biocide.

[0044] Biocides include, but are not limited to, Kathon™, Kathon™CG / ICP II, and Bioban from Dupont / Dow Chemical Co. Their active ingredients are 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one.

[0045] Polycrystalline silicon CMP compositions may contain pH adjusters.

[0046] The polycrystalline silicon polishing composition can be adjusted to an optimized pH value using acidic or alkaline pH adjusters.

[0047] pH adjusters include, but are not limited to, nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid, other inorganic or organic acids and their mixtures.

[0048] pH adjusters also include alkaline pH adjusters, such as sodium hydroxide, potassium hydroxide, ammonium hydroxide, tetraalkylammonium hydroxide, organic quaternary ammonium hydroxide, organic amines, and other chemical reagents that can be used to adjust the pH towards a more alkaline direction.

[0049] The polycrystalline silicon CMP composition contains 0% to 1% by weight; preferably 0.01% to 0.5% by weight; more preferably 0.02% to 0.25% by weight of a pH adjuster.

[0050] The polycrystalline silicon CMP composition contains 0.01% to 10.0% by weight, preferably 0.025% to 1.0% by weight, or most preferably 0.05% to 0.5% by weight of a first chemical additive, wherein the first chemical additive comprises molecules containing quaternary ammonium compounds.

[0051] The polycrystalline silicon CMP composition contains 0.005% to 1.0% by weight, or preferably 0.01% to 0.5% by weight, of a second chemical additive, wherein the second chemical additive comprises a sulfonic acid compound.

[0052] Preferably, the first chemical additive comprises ethyltrimethylammonium hydroxide, and the second chemical additive comprises benzenesulfonic acid.

[0053] The concentration of the second chemical additive (Si promoting compound) can be 0.01 to 0.2% by weight, or preferably 0.01 to 0.05% by weight.

[0054] In some embodiments, the ratio of the first chemical additive to the second chemical additive in the CMP formulation is between about 4:1 and about 1:4, preferably about 3:1 to about 1:3, and most preferably about 2:1 to about 1:2.

[0055] The formulation can be transported in concentrate form and diluted with water upon use. The concentration of components in the concentrate increases according to the dilution factor upon use. In the illustrated embodiment, the dilution factor is from about 2 to about 10 times, preferably from about 3 to about 8 times.

[0056] In some embodiments, the formulation is provided as a single-package concentrated slurry having excellent particle stability, defined by measuring particle size change over an aging period of at least 10 days at 50 degrees Celsius. The slurry is considered stable when the particle size change over at least 10 days is less than 5 nm, or preferably less than 3 nm, or most preferably less than 2 nm.

[0057] In another embodiment, the slurry can be prepared in multiple packages, one of which may be rich in abrasive particles and another of which may be rich in chemical additives; and the different packages are used in combination with diluent water and optionally an oxidant for polishing purposes.

[0058] The polishing removal rate of the polycrystalline silicon film is preferably greater than 5000 Å / min, more preferably greater than 6000 Å / min, or most preferably greater than 7000 Å / min.

[0059] The substrate disclosed above may also include a dielectric film. The dielectric film may be any suitable film, such as silicon nitride or silicon oxide, or any film containing silicon, carbon, and oxygen elements in various component concentrations.

[0060] Silica films can be deposited using many different techniques. Typically, silica films are deposited using a tetraethyl orthosilicate precursor via chemical vapor deposition (CVA), known as TEOS films. Other commonly used silica film types are HDP (high-density plasma) oxides and thermal oxides.

[0061] In a preferred embodiment, the removal selectivity of the polycrystalline silicon film removal rate versus the silicon nitride film removal rate is greater than 50, preferably greater than 70, and more preferably greater than 80, wherein the dielectric film can be silicon oxide or silicon nitride film.

[0062] The following non-limiting embodiments are intended to further illustrate the subject matter of this disclosure.

[0063] CMP method In the examples given below, the CMP experiments were run using the following procedures and experimental conditions.

[0064] Metrology The films were measured using a KLA FX5 ellipsometry system. A 49-point diameter scan (5 mm edge exclusion) was performed on the films before and after polishing to measure the removal rates of polysilicon, TEOS, and SiN films.

[0065] CMP equipment The CMP equipment used was a 300mm Ebara Frex 300X. The wafer was polished using an IC1010 polishing pad supplied by DuPont, Inc., 451 Bellevue Rd., Newark, DE 19713.

[0066] Polishing experiment The baseline conditions for the equipment were: stage speed: 103 rpm, head speed: 97 rpm, membrane pressure: 2.5 psi, and composition flow rate: 250 ml / min. The polishing pad used in the test was an IC1070 pad supplied by DuPont. In-situ dressing was performed using a Saesol dressing disc (part number AM02B8031C7) at 3.2 psi for testing.

[0067] Chips In the examples given below, the CMP experiments were run using the following procedures and experimental conditions.

[0068] Components High-purity colloidal silica: used as an abrasive, with an average particle size ranging from approximately 40 nm to 120 nm, supplied by FUSOCHEMICAL Co., LTD, Japan.

[0069] Chemical additives such as benzenesulfonic acid (BSA) were supplied by Sigma-Aldrich, St Louis, Mo. Ethyltrimethylammonium hydroxide (ETMAH) was supplied by Sachem, Woodward St. Austin, Texas. KOH, used as a pH adjuster, was supplied by Samchun, South Korea.

[0070] Polishing pads: Polishing pads IC1070 and other pads are used in the CMP process and are supplied by DuPont.

[0071] The CMP process uses a dressing device supplied by Saesol Inc. Seonggok-dong, Ansan, South Korea.

[0072] 1. Preparation of slurry for testing For polishing tests, a slurry is prepared by mixing abrasives and chemicals in sequence, and the pH is adjusted with KOH.

[0073] 2. CMP equipment The CMP equipment used was a 300mm Ebara manufactured by Ebara Technologies, Inc., 51 Main Avenue, Sacramento, CA 95838. IC1070 polishing pads, supplied by DOW, Inc., 451 Bellevue Rd., Newark, Del. 19713, were used for blanket-covered and patterned wafer research. The IC1070 pads, or other pads, were run-in using DIW with dressing at 9 lbf for 30 min and dressing at 5 lbf for 10 min.

[0074] 3. Chips Polishing experiments were performed using PECVD, LPCVD, or HD TEOS wafers purchased from Advantech (ADV) Co., Ltd., Hibiya-Kokusai, Chiyoda-ku, Tokyo, Japan. LP-SiN and polycrystalline silicon wafers were purchased from ADV Co., Ltd., Hibiya-Kokusai, Chiyoda-ku, Tokyo, Japan.

[0075] 4. Polishing Experiment In the blanket-coated wafer study, oxide blanket-coated wafers and SiN blanket-coated wafers were polished under baseline conditions. The baseline equipment conditions were: stage speed: 103 rpm; head speed: 97 rpm; polishing pressure: 2.5 psi; slurry flow rate: 250 ml / min.

[0076] The thickness of these wafers was measured using an F5X from KLA-Tencor Corporation 1 Technology Drive Milpitas, CA 95035.

[0077] Working Example Tables 1 and 2 show the polishing performance and removal rates corresponding to the test formulations. Removal rate data for polycrystalline silicon (Poly-Si), SiN, and TEOS were collected. The average particle size of abrasive 1 was 80 nm, abrasive 2 was 40 nm, and abrasive 3 was 120 nm. The slurry pH was adjusted to 10.5. The water-soluble solvent was deionized (DI) water.

[0078] Example 1. Comparison of the selectivity of Poly-Si:SiN using various additives and abrasives.

[0079] In Example 1, the removal rates of silicon nitride, TEOS, and polycrystalline silicon were examined using different formulations based on piperidine and ETMAH. The pH range was 8 to 12. Abrasives of different sizes were tested.

[0080] Table 1. Membrane removal rate and Poly-Si:SiN selectivity.

[0081] As shown in Table 1, higher amounts of ETMAH in the formulation exhibited lower SiN removal rates than those in the piperidine formulation. Similarly, in Examples 3 and 4, increasing the amount of ETMAH from 0.2% to 0.24% resulted in a decrease in SiN removal rate from 12 Å / min to 10.5 Å / min, thereby achieving high Poly-Si:SiN selectivity (from 451.2 to 531.1).

[0082] Example 2. Comparison of Poly-Si:SiN selectivity based on acid type and concentration In Example 2, this is an example of reducing the SiN removal rate while maintaining the Poly-Si removal rate at an appropriate level (>6000 Å / min). In each formulation, 3% by weight of silica abrasive, 0.1 to 0.3% by weight of acidic additive (acid), and 0.09 to 0.5% by weight of pH adjuster were used. The test results are listed in Table 2.

[0083] Table 2. Membrane removal rate of acid additives

[0084] As shown in Table 2, the formulation containing 0.1% benzenesulfonic acid (No. 1) exhibited a low SiN removal rate of 79.5 Å / min and a high Poly-Si:SiN selectivity of <85 compared to other formulations, with the highest Poly-Si removal rate of 6774 Å / min.

[0085] Table 2 shows the polishing performance and removal rate corresponding to these formulations. Data on polysilicon removal rate, SiN removal rate, and TEOS removal rate were collected.

[0086] By optimizing the abrasive concentration and additive concentration, a combination of high polycrystalline silicon film removal rate and low silicon nitride removal rate was achieved. A polycrystalline silicon to silicon nitride selectivity of greater than 80 was achieved with a ratio of the first chemical additive (ETMAH) to the second chemical additive (BSA) of approximately 1:1 to approximately 1:2.

[0087] The embodiments listed above, including working examples, are examples of numerous embodiments available from this disclosure. It is conceivable that many other configurations of the process can be used, and that the materials used in the process can be selected from a wide range of materials other than those specifically disclosed.

Claims

1. A chemical mechanical polishing composition comprising: Abrasives containing silica particles; 0.01% to 10.0% by weight, preferably 0.025% to 1.0% by weight, or most preferably 0.05% to 0.5% by weight of a first chemical additive, wherein the first chemical additive comprises molecules containing a quaternary ammonium compound; 0.005% to 1.0% by weight, or preferably 0.01% to 0.5% by weight, of a second chemical additive, wherein the second chemical additive comprises a sulfonic acid compound; Water-soluble solvents; and Optional biocides; and pH adjuster; The pH of the chemical mechanical polishing composition is preferably 8 to 12, more preferably 9 to 11, and most preferably 9.5 to 10.

5.

2. The chemical mechanical polishing composition according to claim 1, wherein the quaternary ammonium compound is selected from ethyltrimethylammonium hydroxide (ETMAH), ethyltrimethylammonium bromide, ethyltrimethylammonium chloride, benzyl ammonium hydroxide, benzalkonium bromide, benzalkonium chloride, hexadecyltrimethylammonium hydroxide, hexadecyltrimethylammonium bromide (CTAB), hexadecyltrimethylammonium chloride, lauryltrimethylammonium hydroxide, lauryltrimethylammonium bromide, lauryltrimethylammonium chloride (LTAC), stearylammonium hydroxide, stearylammonium bromide, stearylammonium chloride, hexadecylpyridinium hydroxide, hexadecylpyridinium bromide, hexadecylpyridinium chloride (cephalopyridinium chloride), poly(diallyl ammonium hydroxide), poly(diallyl ammonium bromide), and poly(diallyl ammonium chloride). (PDMDAAC), Trimethylstearylammonium hydroxide, Trimethylstearylammonium bromide, Trimethylstearylammonium chloride, Dimethyl di-octadecylammonium hydroxide, Dimethyl di-octadecylammonium bromide, Dimethyl di-octadecylammonium chloride, Tetraalkylammonium hydroxide, Tetraalkylammonium bromide, Tetraalkylammonium chloride, Tetramethylammonium hydroxide (TMAH), Tetramethylammonium bromide, Tetramethylammonium chloride, Tetraethylammonium hydroxide, Tetraethylammonium bromide, Tetraethylammonium chloride, Tetrapropylammonium hydroxide, Tetrapropylammonium bromide, Tetrapropylammonium chloride, Tetrabutylammonium hydroxide, Tetrabutylammonium bromide, Tetrabutylammonium chloride, Ethyltrimethylammonium hydroxide, Ethyltrimethylammonium bromide, Ethyltrimethylammonium chloride, Diethyldimethylammonium hydroxide, Diethyldimethylammonium bromide, Diethyldimethylammonium chloride, Methyltriethylammonium hydroxide, Methyltriethylammonium bromide, Methyltriethylammonium chloride, Choline hydroxide, Choline bromide, Choline chloride, Choline bicarbonate, Hydroxytartrate choline and other choline salts.

3. The chemical mechanical polishing composition according to claim 1, wherein the second chemical additive is selected from methanesulfonic acid (MSA), benzenesulfonic acid (BSA), toluenesulfonic acid, p-toluenesulfonic acid, 2-naphthalenesulfonic acid, naphthalene-1-sulfonic acid, dodecylbenzenesulfonic acid (DDBSA), camphorsulfonic acid, ligninsulfonic acid, and poly(styrenesulfonic acid) (PSSA), ethylenedisulfonic acid, naphthalene-2-sulfonic acid, and naphthalenedisulfonic acid.

4. The chemical mechanical polishing composition according to claim 2, wherein the first chemical additive comprises ethyltrimethylammonium hydroxide.

5. The chemical mechanical polishing composition according to claim 3, wherein the second chemical additive comprises benzenesulfonic acid.

6. The chemical mechanical polishing composition according to claim 1, further comprising amino acids.

7. The chemical mechanical polishing composition according to claim 6, wherein the amino acid is glycine.

8. The chemical mechanical polishing composition according to claim 1, wherein the first chemical additive comprises ethyltrimethylammonium hydroxide, and the second chemical additive comprises benzenesulfonic acid.

9. The chemical mechanical polishing composition according to claim 1, wherein the ratio of the first chemical additive to the second chemical additive is about 4:1 to about 1:4, preferably about 3:1 to about 1:3, and most preferably about 2:1 to about 1:

2.

10. A method for chemically mechanically polishing (CMP) a semiconductor substrate, said semiconductor substrate having at least one surface comprising a film containing polycrystalline silicon and silicon nitride, said method comprising: Provide the semiconductor substrate; Polishing pads are provided; Provides the chemical mechanical polishing (CMP) composition according to claim 1; The surface of the semiconductor substrate is brought into contact with the polishing pad and the chemical mechanical polishing composition; and Polish the at least one surface.

11. The method of claim 10, wherein the selectivity of the polysilicon removal rate relative to the silicon nitride removal rate is greater than about 50, preferably greater than about 70, and more preferably greater than about 80.

12. The method of claim 10, wherein the removal rate of polysilicon is greater than about 5000 Å / min, preferably greater than about 6000 Å / min, and most preferably greater than about 6500 Å / min.

13. A system for chemically mechanically polishing (CMP) a semiconductor substrate, said semiconductor substrate having at least one surface comprising a polycrystalline silicon-containing film, said system comprising: a. The semiconductor substrate; b. The chemical mechanical polishing (CMP) composition according to claim 1; and c. Polishing pad; The at least one of the polycrystalline silicon-containing surfaces is in contact with the polishing pad and the chemical mechanical polishing composition.

14. The system of claim 13, wherein the semiconductor substrate further comprises a silicon oxide film, wherein the silicon oxide film is selected from chemical vapor deposition (CVD), plasma-enhanced CVD (PECVD), high-density deposition CVD (HDP), or spin-coated silicon oxide film.

15. The system of claim 13, wherein the semiconductor substrate further comprises a silicon nitride film.

16. The system of claim 15, wherein the selectivity of the polysilicon removal rate relative to the silicon nitride removal rate is greater than about 50, preferably greater than about 70, and more preferably greater than about 80.

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