WO2008011796A1

WO2008011796A1 - Polishing slurry for low dielectric material

Info

Publication number: WO2008011796A1
Application number: PCT/CN2007/002103
Authority: WO
Inventors: Jery Guodong Chen; Peter Weihong Song; Judy Jianfen Jing; Sunny Chun Xu; Yuan Gu
Original assignee: Anji Microelectronics (Shanghai) Co., Ltd
Priority date: 2006-07-21
Filing date: 2007-07-09
Publication date: 2008-01-31
Also published as: CN101490734B; CN101108952A; CN101490734A

Abstract

A polishing slurry including Al-doped silica and water for low dielectric material is disclosed, it is characterized in that, it further contains active micro-molecule materials which are ammonium-ion or quaternary ammonium ion containing compound. The present polishing slurry has promotion on polishing low dielectric material such as CDO and TEOS or SION etc., while it has little effect on polishing speed for Ta and Cu. Thus it can greatly improve the polishing selectivity for substrates. Moreover, the present polishing slurry can greatly decrease the surface defects such as scratch, corrosion, pitting erosion and the like.

Description

Polishing liquid for polishing low dielectric materials

The present invention relates to a polishing liquid, and more particularly to a polishing liquid for polishing a low dielectric material. technical background

In the manufacture of integrated circuits, the standard of interconnect technology is increasing, and a layer is deposited on top of one layer, so that an irregular topography is formed on the surface of the substrate. One method of planarization used in the prior art is chemical mechanical polishing (CMP), which uses an abrasive-containing mixture and a polishing pad to polish an integrated circuit surface. In a typical chemical mechanical polishing process, the substrate is placed in direct contact with a rotating polishing pad and a load is applied to the back side of the substrate with a load. During polishing, the gasket and the table rotate while maintaining a downward force on the back of the substrate, applying abrasive and chemically active solutions (often referred to as polishing fluids or polishing slurries) to the gasket. The polished film undergoes a chemical reaction to begin the polishing process.

The C P polishing liquid mainly includes abrasives, chemicals, solvents, and the like. The abrasive is mainly various inorganic or organic particles such as silica, alumina, zirconia, cerium oxide, iron oxide, polymer particles and/or mixtures thereof. The solvent of the CMP polishing liquid is mainly water or an alcohol. Chemical reagents are used to control polishing rate and polishing selectivity, improve polishing surface performance, and improve the stability of the polishing solution, including oxidizing agents, complexing agents, corrosion inhibitors, and/or surfactants.

In some published patents, ammonium salts and quaternary ammonium species are used to adjust the polishing rate of some non-metallic materials. For example, in CN 1498931 A, in the polishing solution of silica as an abrasive, a water-soluble quaternary ammonium salt is used. The polishing rate of the polysilicon is improved and the stability of the polishing liquid is improved, and the ratio of the polishing rate of the polysilicon film to the polishing rate of the nitride film reaches 50. Such as USP 6,046,112, the polishing liquid includes Zr0 ₂ abrasive, surfactant, TMAH or TBAH, and water, which have a higher polishing rate and higher polishing selectivity for SQG, polishing rate up to 4000 A/min, polishing selectivity up to 8, but using Zr0 ₂ Abrasive, expensive. In USP 7018560, an organic quaternary ammonium salt having a length of from 2 to 15 carbon chains is used to increase the polishing rate of TEOS while reducing the polishing rate of materials such as SiC, SiCN, Si ₃ N ₄ and SiCO. However, in the above patents, ammonium salts and quaternary ammonium species are not used to increase the polishing rate of the low dielectric material CDO.

As the complexity of integrated circuits increases and the size of devices decreases, some low dielectric materials containing Si, C, and O are gradually being applied to integrated circuits to improve the opening and closing capabilities of future integrated circuits. Low dielectric materials include carbon-doped silicon dioxide (CDO), silicon oxycarbide (SiOC), and organosilicon glass (OSG), while carbon-doped silicon dioxide (CDO) is a widely used low dielectric material. . These low dielectric materials will replace silicon dioxide (such as TEOS, FSG, SOG, etc.) in the future to form an insulating layer in integrated circuits.

Summary of invention

SUMMARY OF THE INVENTION It is an object of the present invention to provide a polishing liquid for polishing a low dielectric material for improving the polishing rate of a low dielectric material, the polishing liquid of the present invention comprising an aluminum-doped silica abrasive and water, characterized in that It is: It also includes small molecule active substances containing ammonium ions or quaternary ammonium salts. Since such a small molecule active material can be used in the polishing liquid of the present invention to form an ammonium ion or a quaternary ammonium ion, the polishing rate of the low dielectric material can be improved, but the polishing rate of bismuth and copper is not significantly affected. Polishing selectivity can be improved.

In the present invention, the term "small molecule active material" means an ammonium ion-containing active material or a quaternary ammonium-based active material having a molecular weight _Mw < 500.

In the present invention, the active material may be ammonia water, various ammonium salts, various quaternary ammonium salts, and each a quaternary ammonium base, preferably ammonia, amino acid, ammonium pentaborate, ammonium tartrate, tetramethylammonium hydroxide

(TMAH), tetrabutylammonium hydroxide (TBAH) and/or tetrabutylammonium tetrafluoroborate, and an ammonium salt or a quaternary ammonium compound having a similar structure, preferably tetrabutylammonium hydroxide and tetrabutylammonium tetrafluoroborate.

The active material is preferably used in an amount of 0.001 to 0.5%, more preferably 0.001 to 0.2%. The concentration of the aluminum-doped silica abrasive may be various concentrations given in the polishing liquid of the prior art polishing integrated circuit substrate, preferably from 1 to 20%, more preferably from 2 to 15%. , water is the balance. The above concentrations all refer to the weight percentage of the entire polishing liquid.

The aluminum-doped silica abrasive is a sol-type aluminum-doped silica dispersion. The sol-type abrasive dispersion can greatly reduce the surface defects of the substrate such as scratches, corrosion, pitting and the like.

The pH of the sol-type aluminum-doped silica dispersion is preferably from 2 to 7.

In the present invention, the particle diameter of the aluminum-doped silica abrasive is preferably 5 to 500 nm, more preferably 5 to; LOOnm, most preferably 20 to 80 nm.

The polishing liquid of the present invention preferably has a pH of from 2 to 7.

The polishing liquid of the present invention may further include various additives in the prior art such as a corrosion inhibitor, an oxidizing agent, a rate increasing agent, a surfactant, and/or other auxiliary agents and the like.

The corrosion inhibitor may be various corrosion inhibitors used in the field of polishing agents, preferably benzotriazole (BTA); the oxidizing agent may be various oxidizing agents used in the field of polishing agents, preferably. The surface is hydrogen peroxide; the surfactant may be various surfactants used in the field of polishing agents, preferably polyethylene glycol (PEG) and/or polyacrylic acid (PAA).

The polishing liquid of the present invention is preferably polished to a material such as carbon-doped silica (CDO); the polishing liquid of the present invention can also be used for polishing silica (TEOS), SiON, Ta or Cu.

In the present invention, the term "low dielectric material" means a material having a dielectric constant of less than 3.0.

The positive progress of the present invention is: The polishing liquid of the present invention is for CDO, TEOS, SiON

3 The polishing of the materials has a promoting effect, but has no significant influence on the polishing rate of bismuth and copper, so that the polishing selectivity of the substrate can be greatly improved. Moreover, the polishing liquid of the present invention can greatly reduce the problem of substrate surface defects such as scratches, corrosion, pitting and the like on the surface of the substrate.

DRAWINGS

Figure 1 is a polishing rate diagram of a polishing liquid-polished low dielectric material containing different active materials; Figure 2 is a graph showing the effect of a polishing solution containing various additives on the polishing rate of a low dielectric material; Effect diagram of the polishing rate of the dielectric material;

Figure 4 is a graph showing the effect of different abrasive concentrations on the polishing rate of low dielectric materials;

Figure 5 is a graph showing the effect of the polishing liquid of the present invention on the polishing rate of different low dielectric materials;

6 is a graph showing the influence of the pH of the polishing liquid of the present invention on the polishing rate of the low dielectric material; FIG. 7 is a graph showing the influence of the different abrasives on the polishing rate of the low dielectric material;

Figure 8 is a graph showing the effect of the particle size of the abrasive on the polishing rate of the low dielectric material.

Summary of the invention

Example 1

Comparative polishing bath 掺 aluminum-doped silica abrasive (45nm) 7%, tartaric acid 0.1%, PEG200 0.2%, BTA 0.2%, H ₂ O ₂ 0.5%, water balance, pH=3;

Polishing solution 1 aluminum-doped silica abrasive (45nm) 7%, tartaric acid 0.1%, PEG200 0.2%, BTA 0.2%, H ₂ O ₂ 0.5%, ammonia water (N OH) 0.1%, water balance, pH=3;

Polishing solution 2 aluminum-doped silica abrasive (45nm) 7%, tartaric acid 0.1%, PEG200 0.2%, BTA O.2%, H ₂ O ₂ 0.5%, ammonium pentaborate 0.1%, water balance, pH=3 _;

Polishing solution 3 with aluminum-doped silica abrasive (45nm) 7%, tartaric acid 0.1%, PEG200 0.2%. BTA O.2%, H ₂ O ₂ 0.5%, ammonium tartrate 0.1%, water balance, pH=3 _;

Polishing solution 4 aluminum-doped silica abrasive (45nm) 7%, tartaric acid 0.1%, PEG200 0.2%, BTA O.2%, H ₂ 0 ₂ 0.5%, tetrabutylammonium tetrafluoroborate 0.02%, water balance, pH=3;

Polishing solution 5 aluminum-doped silica abrasive (4'5nm) 7%, tartaric acid 0.1%, PEG200 0.2%, BTA 0.2%, H ₂ O ₂ 0.5%, tetramethylammonium hydroxide (TMAH) 0.025%, water Amount, pH=3 _; polishing solution 6 with aluminum-silica abrasive (45nm) 7%, tartaric acid 0.1%, PEG200 0.2%, BTA O.2%, H ₂ O ₂ 0.5%, tetrabutylammonium hydroxide (TBAH) 0.01 %, water balance, pH=3.

Polishing material: BD material; polishing conditions: lpsi, polishing disk speed 70 rpm, polishing pad Politex, polishing fluid flow rate 100 ml/min, Logitech PM5 Polisher o

The results are shown in Fig. 1. The polishing liquid containing active material of the present invention can significantly improve the polishing rate of the low dielectric material BD, especially tetrabutylammonium hydroxide and tetrabutylammonium tetrafluoroborate, and the polishing rate reaches 600A. /min or more.

Example 2

Contrast polishing solution 7, aluminum-doped silica abrasive (45nm) 6%, water balance, pH=3 _;

Polishing solution 7 with aluminum silica abrasive (45nm) 6%, ammonium pentaborate 0.1%, water balance, pH = 3; Comparative polishing solution 8, aluminum-doped silica abrasive (45nm) 6%, tartaric acid 0.2%, Water balance, pH=3;

Polishing solution 8 miscellaneous aluminum silica abrasive (45nm) 6%, tartaric acid 0.2%, ammonium pentaborate 0.1%, water balance, pH=3 _;

Comparative polishing solution 9, aluminum-doped silica abrasive (45nm) 6%, tartaric acid 0.2%, BTA 0.2%, H ₂ O ₂ 0.5%, water balance, pH = 3;

Polishing solution 9 aluminum-doped silica abrasive (45 nm) 6%, tartaric acid 0.2%, BTA 0.2%, 3⁄40 ₂ 0.5%, ammonium pentaborate 0.1 ° /. , water balance, pH=3;

Comparative polishing liquid 10' aluminum-doped silica abrasive (45nm) 6%, tartaric acid 0.2%, BTA 0.2%, H ₂ O ₂ 0.5%, PEG200 0.2%, water balance, pH = 3; N2007/002103 Polishing solution 10 with aluminum silica abrasive (45nm) 6%, tartaric acid 0.2%, BTA 0.2%, H ₂ O ₂ 0.5%, PEG200 0.2%> ammonium pentaborate 0.1%, water balance, pH=3 .

Polishing material: BD material; polishing conditions: lpsi, polishing disk speed 70 rpm, polishing pad Politex, polishing fluid flow rate 100 ml/min, Logitech PM5 Polisher ₀

As a result, as shown in Fig. 2, the polishing liquid containing the active material of the present invention can remarkably improve the polishing rate of the low dielectric material BD, and can better 'improve the polishing rate with various additives. 'Example 3

Contrast polishing solution 1 Γ 铝 aluminum silica abrasive (45nm) 7%, tartaric acid 0.1%, PEG200 0.2%, BTA O.2%, H ₂ O ₂ 0.5%, water balance, pH = 3;

Polishing solution 11 (1) aluminum-doped silica abrasive (45 nm) 7%, tartaric acid 0.1%, PEG200 0.2%, BTA 0.2%, H ₂ O ₂ 0.5%, tetramethylammonium hydroxide 0.0125%, water balance, pH=3; Polishing solution 11(2) Miscellaneous aluminum silica abrasive (45nm) 7%, tartaric acid 0.1%, PEG200 0.2%, BTA O.2%, H ₂ O ₂ 0.5%, tetramethylammonium hydroxide 0.025 %, water balance, pH=3; polishing solution 11 (3) aluminum-doped silica abrasive (45 nm) 7%, tartaric acid 0.1%, PEG200 0.2%, BTA 0.2%, H ₂ O ₂ 0.5%, tetramethyl Ammonium hydroxide 0.05%, water balance, pB=3; polishing solution 11 (4) aluminum-doped silica abrasive (45 nm) 7%, tartaric acid 0.1%, PEG200 0.2%, BTA O.2%, H ₂ O ₂ 0.5%, tetramethylammonium hydroxide 0.125%, water balance, pH=3; polishing solution 11(5) aluminum-doped silica abrasive (45nm) 7%, tartaric acid 0.1%, PEG200 0.2%, BTA O.2 % H ₂ O ₂ 0.5%, tetramethylammonium hydroxide 0.2%, water balance, pH=3.

Polishing material: BD material and TEOS material; polishing conditions: lpsi, polishing disk speed 70 rpm, polishing pad Politex, polishing fluid flow rate 100 ml/min, Logitech PM5 Polisher o

The results are shown in Fig. 3. After the active material is added to the polishing liquid of the present invention, not only the polishing rate of the low dielectric material BD but also the polishing of TEOS can be accelerated. As the amount of active material increases, the polishing liquid of the present invention gradually enhances the polishing effect of the low dielectric material BD and TEOS materials, and gradually decreases after reaching a certain value. Explain only when the amount of active substance is used When 02103 is a specific value, the polishing rate of the low dielectric material BD can be promoted. Otherwise, excessive active material will inhibit the polishing of BD and TEOS.

Example 4

Comparative polishing solution 12, (1) aluminum-doped silica abrasive (45 nm) 0.5%, water balance, pH = 3 _; comparative polishing liquid 12, (2) aluminum-doped silica abrasive (45 nm) 2%, water Quantity, pH=3 _;

Comparative polishing solution 12, (3) aluminum-doped silica abrasive (45 nm) 5%, water balance, pH = 3 _;

Comparative polishing solution 12, (4) aluminum-doped silica abrasive (45 nm) 10%, water balance, pH = 3 _; comparative polishing liquid 12, (5) aluminum-doped silica abrasive (45 nm) 15%, water Amount, pH = 3 _; comparative polishing liquid 12, (6) aluminum-doped silica abrasive (45 nm) 20%, water balance, pH = 3. Polishing solution 12 (1) aluminum-doped silica abrasive (45nm) 0.5%, tetrabutylammonium hydroxide 0.007%, water balance, pH = 3;

Polishing solution 12 (2) aluminum-doped silica abrasive (45nm) 2%, tetrabutylammonium hydroxide 0.007%, water balance, pH=3;

Polishing solution 12 (3) aluminum-doped silica abrasive (45nm) 5%, tetrabutylammonium hydroxide 0.007%, water balance, pH = 3;

Polishing solution 12 (4) miscellaneous aluminum silica abrasive (45nm) 10%, tetrabutylammonium hydroxide 0.007%, water balance, pH = 3;

Polishing solution 12 (5) aluminum-doped silica abrasive (45nm) 15%, tetrabutylammonium hydroxide 0.007%, water balance, pH = 3;

Polishing solution 12 (6) aluminum-doped silica abrasive (45 nm) 20%, tetrabutylammonium hydroxide 0.007%, water balance, pH=3.

Polishing material: BD material; polishing conditions: lpsi, polishing disk speed 70 rpm, polishing pad Politex, polishing solution flow rate 100 ml/min, Logitech PM5 Polisher ₀

The results are shown in Fig. 4: When the concentration of the aluminum-doped silica is between 0.5% and 20%, the active liquid-containing polishing liquid of the present invention can be significantly increased with respect to the polishing liquid containing no active material. The polishing rate of the dielectric material BD.

Example 5

Comparative polishing liquid 13, aluminum-doped silica abrasive (45nm) 7%, tartaric acid 0.1%, PEG200 0.2%, BTA 0.2%, H ₂ O ₂ 0.5%, water balance, pH = 3;

Polishing solution 13 aluminum-doped silica abrasive (45nm) 7%, tartaric acid 0.1%, PEG200 0.2%, BTA 0.2%, H ₂ O ₂ 0.5%, tetramethylammonium hydroxide 0.025%, water balance, pH=3 .

Polishing materials: BD material, TEOS material, SiON material, Ta material and Cu material; Polishing conditions: lpsi, polishing disk speed 70 rpm, polishing pad Politex, polishing liquid flow rate 100 ml/min, Logitech PM5 Polisher.

The results are shown in Fig. 5: The polishing liquid containing the active material of the present invention can improve the polishing rate of various non-metal materials, such as BD material, TEOS material, and SiON material, but with respect to the metal, relative to the polishing liquid containing no active material. The polishing rate of Ta and Cu does not have much influence, so the polishing liquid of the present invention can improve the polishing selectivity of the substrate.

Example 6

Comparative polishing liquid 14, (1) aluminum-doped silica abrasive (45nm) 7%, tartaric acid 0.1%, PEG200 0.2%, BTA O.2%, H ₂ O ₂ 0.5%, water balance, pH = 2;

Comparative polishing solution 14, (2) aluminum-doped silica abrasive (45nm) 7%, tartaric acid 0.1%, PEG200 0.2%, BTA 0.2%, H ₂ O ₂ 0.5%, water balance, pH = 3;

Comparative polishing liquid 14, (3) aluminum-doped silica abrasive (45nm) 7%, tartaric acid 0.1%, PEG200 0.2%, BTA O.2%, H ₂ O ₂ 0.5%, water balance, pH = 5;

Comparative polishing liquid 14, (4) aluminum-doped silica abrasive (45nm) 7%, tartaric acid 0.1%, PEG200 0.2%, BTA 0.2%, H ₂ O ₂ 0.5%, water balance, pH = 7;

Polishing solution 14 (1) aluminum-doped silica abrasive (45 nm) 7%, tartaric acid 0.1%, PEG200 0.2%, BTA 0.2%, H ₂ O ₂ 0.5%, tetramethylammonium hydroxide 0.025%, water balance, pH=2 _; polishing solution 14(2) aluminum-doped silica abrasive (45nm) 7%, tartaric acid 0.1%, PEG200 3

0.2%, BTA 0.2%, H ₂ O ₂ 0.5%, tetramethylammonium hydroxide 0.025%, water balance, pH=3 _;

'Polishing fluid 14 (3) 5% aluminum-doped silica abrasive (45 nm), tartaric acid 0.1 ° /. , PEO200 0.2%, BTA 0.2%, H ₂ O ₂ 0.5%, tetramethylammonium hydroxide 0.025%, water balance, pH=5; polishing solution 14(4) aluminum-doped silica abrasive (45nm) 7% , tartaric acid 0.1%, PEG200 0.2%, BTA O.2%, H ₂ O ₂ 0.5%, tetramethylammonium hydroxide 0.025%, water balance, pH=7.

Polishing conditions: lpsi, polishing disk speed 70 rpm, polishing pad Politex, polishing fluid flow rate 1 OOml/min, Logitech PM5 Polisher.

The results are shown in Fig. 6. When the pH of the polishing liquid is 2 to 7, the polishing liquid containing the active material of the present invention can significantly increase the polishing rate of the low dielectric material BD with respect to the polishing liquid containing no active material.

Example 7

Comparative polishing liquid 15, (1,) silica abrasive (70 nm, PL-3, Fuso Company) 7%, tartaric acid 0.1%, PEG200 0.2%, ΒΤΑ 0. 2%, Η ₂ 0 ₂ 0.5%, water balance , ρΗ=3;

Comparative polishing liquid 15, (1) silica abrasive (70 nm, PL-3, Fuso Company) 7%, tartaric acid 0.1%, PEG200 0.2%. BTAO.2%, H ₂ O ₂ 0.5%, tetramethyl hydroxide 0.025% ammonium, water balance, pH=3 _;

Comparative polishing solution 15, (2,) A1 ₂ 0 ₃ coated silica abrasive (Al ₂ 0 ₃ -coated silica) (35 nm) 7%, tartaric acid 0.1%, PEG200 0.2% > BTA 0.2%, H ₂ O ₂ 0.5%, water balance, pH=3 _; contrast polishing liquid 15, (2) A1 ₂ 0 ₃ coated silica abrasive (1 ₂ 0 ₃ (^6 (1 silica) (35nm) 7%, tartaric acid 0.1%, PEG200 0.2%. BTA 0.2%, H ₂ 0 ₂ 0.5%, tetramethylammonium hydroxide 0.025%, water balance, pH=3;

Comparative polishing liquid 15, (3,) Zr0 ₂ coated silica abrasive (Zr0 ₂ -coated silica) (20 nm) 7%, tartaric acid 0.1%, PEG200 0.2%, BTA O.2%, H ₂ 0 ₂ 0.5 %, water balance, pH=3 _; contrast polishing liquid 15, (3) Zr0 ₂ coated silica abrasive (Zr0 ₂ -coated silica) (20nm) 7%, tartaric acid 0.1%, PEG200 0.2%, BTAO. 2%, H ₂ O ₂ 0.5%, tetramethylammonium hydroxide 07 002103

0.025%, water balance, pH=3;

Comparative polishing liquid 15'(4') fumed silica (initial particle size 15nm) 7%, tartaric acid 0.1%, PEG200 0.2%, BTA O.2%, H ₂ 0 ₂ 0.5%, water balance , pH=3;

Comparative polishing liquid 15' (4) Fumed silica (initial particle size 15nm) 7%, tartaric acid 0.1%, PEG200 0.2%, BTA 0.2%, H ₂ O ₂ 0.5%, tetramethylammonium hydroxide 0.025%, water balance, pH=3 _;

Comparative polishing liquid 15 (5') aluminum-doped alumina abrasive (45nm) 7%, tartaric acid 0.1%, PEG200 0.2%, BTA 0.2%, H ₂ O ₂ 0.5%, water balance, pH = 3;

Polishing solution 15(5) Al-doped silica abrasive (45nm) 7%, tartaric acid 0.1%, PEG200 0.2%, BTA 0.2%, H ₂ O ₂ 0.5%, tetramethylammonium hydroxide 0.025%, water balance, pH = 3.

Polishing material: BD material; polishing conditions: lpsi, polishing disk speed 70 rpm, polishing pad Politex, polishing fluid flow rate 100 ml/min, Logitech PM5 Polisher.

The results are shown in Fig. 7. After the active material was added to the polishing liquid containing aluminum-doped silica as an abrasive, the polishing rate of the low dielectric material BD was remarkably improved. When the active material is added to the polishing liquid of some other abrasives, the polishing rate of the low dielectric material BD may decrease.

Example 8

Comparative polishing liquid 16' aluminum-doped silica abrasive (20nm) 10%, oxalic acid 0.2%, BTA 0.2%, H ₂ O ₂ 0.3%, water balance, pH = 3;

The polishing liquid 16 is doped with aluminum silica abrasive (20 nm) 10%, oxalic acid 0.2%, BTA 0.2%, H ₂ 0 ₂ 0.3%, tetrabutylammonium hydroxide 0.01%, water balance, pH=3;

Comparative polishing liquid 17, aluminum-doped silica abrasive (50 nm) 10%, oxalic acid 0.2%, BTA 0.2%, H ₂ O ₂ 0.3%, water balance, pH = 3;

Polishing liquid 17 miscellaneous aluminum silica abrasive (50nm) 10%, oxalic acid 0.2%, BTA 0.2%, H ₂ 0 ₂ 0.3%, tetrabutylammonium hydroxide 0.01%, water balance, pH = 3;

Comparative polishing solution 18, aluminum-doped silica abrasive (80 nm) 10%, oxalic acid 0.2%, ΒΤΑ 0·2 °/. , H ₂ 0 ₂ 0.3% water balance, ρΗ=3;

The polishing solution 18 was doped with aluminum silica abrasive (80 nm) 10%, oxalic acid 0.2 °/. , BTA 0.2%, H ₂ 0 ₂ 0.3%, tetrabutylammonium hydroxide 0.01%, water balance, pH=3.

Polishing material: BD material; Polishing conditions: lpsi, polishing disk rotation rate 70 rpm, polishing pad Politex, polishing fluid flow rate 100 ml/min, Logitech PM5 Polisher.

The results are shown in Fig. 8. The aluminum-doped silica abrasives of 20 to 80 nm are suitable for the present invention, and as the abrasive grain size increases, the polishing rate increases, so that the aluminum-silica abrasives larger than 80 nm are also suitable. this invention.

The materials and reagents used in the present invention are all commercially available products, and the sulphide silica abrasives are all referred to as sol-type aluminum-doped silica abrasive dispersions.

Claims

Rights request

A polishing liquid for polishing a low dielectric material, the polishing liquid comprising an aluminum-doped silica abrasive and water, characterized in that it further comprises a small molecule active material containing an ammonium ion or a quaternary ammonium.

2. The polishing liquid according to claim 1, wherein: the active material comprises ammonia water, ammonium pentaborate, ammonium tartrate, tetramethylammonium hydroxide, tetrabutylammonium hydroxide, and/or tetrabutyltetrafluoroethylene. Ammonium borate.

The polishing liquid according to claim 2, wherein the active material is used in an amount of from 0,001 to 0.5%.

The polishing liquid according to claim 3, wherein the concentration of the aluminum-silica abrasive is 1 to 20%.

The polishing liquid according to any one of claims 1 to 4, wherein the aluminum-doped silica abrasive is a sol-type aluminum-doped silica dispersion.

The polishing liquid according to claim 5, wherein the sol type aluminum silicon dioxide dispersion has a pH of 2 to 7.

The polishing liquid according to claim 5, wherein the particle size of the aluminum-silica abrasive is 5 to 500 nm.

The polishing liquid according to claim 7, wherein the aluminum-doped silica abrasive has a particle diameter of 5 to 1 00 nm.

The polishing liquid according to any one of claims 1 to 4, wherein the polishing liquid has a pH of 2 to 7.

The polishing liquid according to any one of claims 1 to 4, wherein the polishing liquid further comprises a corrosion inhibitor, an oxidizing agent, a rate increasing agent and/or a surfactant.

The polishing liquid according to any one of claims 1 to 4, wherein the low dielectric material is carbon-doped silica.