WO2008040183A1

WO2008040183A1 - A chemical-mechanical polishing liquid for polishing low-dielectric material

Info

Publication number: WO2008040183A1
Application number: PCT/CN2007/002808
Authority: WO
Inventors: Judy Jianfen Jing; Peter Weihong Song; Jery Guodong Chen; Daisy Ying Yao
Original assignee: Anji Microelectronics (Shanghai) Co., Ltd.
Priority date: 2006-09-29
Filing date: 2007-09-24
Publication date: 2008-04-10
Also published as: CN101541902A; CN101153205A

Abstract

A chemical-mechanical polishing liquid for polishing low-dielectric material is disclosed, which comprises abrasive particles, corrosion inhibitor, oxidizer and water, and the characteristic of the liquid is in that further comprises at least one kind of accelerator. The polishing liquid have higher removal rate for low-dielectric material under lower pressure, and also have higher removal rate for other material such as metal copper (Cu), silica (Teos), metal tantalum (Ta)/ tantalum nitride (TaN) barrier and the like.

Description

Chemical mechanical polishing liquid for polishing low dielectric materials

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

Conventional dielectric material (such as TEOS) has a higher dielectric constant, which leads to an increase in capacitance between the conductive layers, which affects the speed of the integrated circuit and reduces the efficiency. With the complication and refinement of the integrated circuit, This kind of substrate material can't meet the technical requirements of more advanced processes (65nm or 45 legs). Introducing low dielectric materials (such as CDO, SOG) into the substrate is an inevitable trend in the development of integrated circuit technology, which has led to many uses. A polishing slurry for low dielectric materials.

However, the current low-dielectric material polishing liquid in the prior art does not achieve the perfect combination of manufacturing cost and technical performance. Patent Document US6046112 discloses an acidic slurry, using an abrasive Z _{r 2,} with hydroxylamine to polishing low dielectric materials SOG. The abrasives used are expensive and the production costs are high. Further, as disclosed in US Pat. No. 6,974,777, a polishing liquid for a low dielectric material comprising a nonionic surfactant having an HLB value greater than 7, which inhibits polishing of a low dielectric material. The rate has little effect on the removal rate of copper and bismuth.

Summary of invention

The object of the present invention is to solve the problem of low removal rate of low dielectric material and difficult control of polishing selection under low pressure, and to provide a novel chemical mechanical polishing liquid of low dielectric material. The polishing solution can have a higher removal rate of low dielectric material at lower pressure, for other Materials such as metallic copper (Cu), silicon oxide (Teos:), and tantalum (Ta)/nitride (TaN) barrier layers also have higher removal rates.

The polishing liquid of the present invention comprises abrasive particles, a corrosion inhibitor, an oxidizing agent and water, and is characterized by further comprising at least one speed increasing agent.

In the present invention, the speed increasing agent may be selected from one or more of the following: inorganic phosphoric acid and salts thereof, and organic phosphoric acid and salts thereof. The inorganic phosphoric acid and salts thereof may be phosphoric acid, phosphorous acid, pyrophosphoric acid, trimellitic acid, hexametaphosphoric acid, tripolyphosphoric acid, polyphosphoric acid, and salts of the above acids. The organic phosphoric acid and the salt thereof may be 2-phosphonium butyrate-1,2,4-tricarboxylic acid (PBTCA), ethylenediaminetetramethylenephosphonic acid (EDTMP), diethylenetriamine pentamethylphosphine Acid (DTPMP), hydroxyethylidene diphosphonic acid (HEDP), aminotrimethylenephosphonic acid (ΑΤΜΡ:), 2-hydroxyphosphonoacetic acid (ΗΡΑΑ:), polyaminopolyether methylene phosphonic acid (ΡΑΡΕΜΡ) ), and the salt of the above acid. The weight percentage of the speed increasing agent is preferably 0.001-2%, more preferably 0.01 to 1%.

In the present invention, the abrasive particles may be any abrasive particles in the prior art, such as silica, alumina, cerium oxide, titanium dioxide, silicon dioxide, aluminum-coated silica. Or high molecular polymer particles. The weight percentage of the abrasive particles is preferably from 1 to 20%, more preferably from 2 to 15%. The particle size of the abrasive particles is preferably from 20 to 150 nm, more preferably from 30 to 120 nm.

In the present invention, the corrosion inhibitor may be an azole compound. The azole compound may be benzotriazole, 1-phenyl-5-mercapto-tetrazole, 2-mercapto-benzothiazole, benzimidazole, 2-mercaptobenzimidazole or 5-amino- 1H-tetrazole and the like. The concentration of the corrosion inhibitor is preferably 0.001 to 1%, more preferably 0.01 to 0.5%.

In the present invention, the oxidizing agent may be hydrogen peroxide, urea peroxide, peracetic acid, potassium persulfate or ammonium persulfate. The concentration of the oxidizing agent is preferably from 0.001 to 5% by weight, more preferably 0.05% by weight.

The polishing liquid of the present invention is an acidic solution, and the pH is preferably 2.0 to 7.0, more preferably 2·0~5·0.

The polishing liquid of the present invention may further comprise a surfactant. The surfactant is a nonionic surfactant, a cationic surfactant or an anionic surfactant.

The polishing liquid of the present invention may further comprise a pH adjusting agent, a viscosity modifier, an antifoaming agent or a bactericide, etc. to attain the effects of the present invention.

The polishing liquid of the present invention can be obtained by adding a certain amount of abrasive particles to a stirrer, adding a certain amount of deionized water and various components at a constant rate and mixing them uniformly, and adjusting them by a known method in the art. The agent can be adjusted to the desired pH value.

The polishing liquid of the present invention preferably polishes a low dielectric material such as a carbon oxide (CDO), such as a carbon-doped silicon dioxide BD, or a low dielectric substrate material such as a porous material.

The positive progress of the present invention is that it can have a higher removal rate of low dielectric materials at lower pressures, and other materials such as metallic copper (Cu), silicon oxide (Teos), and metal tantalum (y nitriding). Tan (TaN) barrier layers, etc. also have higher removal rates. The effect will be further illustrated by comparative experiments in the examples.

DRAWINGS

1 is a polishing liquid of Comparative Example 1 and a polishing liquid 1 to 13 containing different kinds of speed increasing agents in Example 1 at a low polishing pressure (l, psi) for a low dielectric material BD (different carbon 2) The effect of the removal rate of silicon oxide). From left to right in Fig. 1, the removal rates of the low dielectric material BD (carbon doped silica) of the polishing liquid of Comparative Example 1, the polishing liquids 1 to 13 of Effect Example 1 were sequentially. As can be seen from the figure, the polishing liquids 1 to 13 to which the speed increasing agent was added in Effect Example 1 can increase the removal rate of the low dielectric material (BD) to a different extent as compared with Comparative Example 1 in which no speed increasing agent was added. 2 is a polishing liquid of Comparative Example 1 and a polishing liquid 14 to 19 containing effector phosphoric acid of different concentrations in Example 2 at a low polishing pressure (lpsi) for a low dielectric material BD (carbon doped two) The effect of the removal rate of silicon oxide). In Fig. 2, from left to right, the removal rates of the low dielectric material BD (carbon doped silica) of the polishing liquid of Comparative Example 1, and the polishing liquids 14 to 19 of Effect Example 2 were sequentially. It can be seen from the figure that compared with Comparative Example 1 in which no accelerating agent is added, the polishing liquids 14 to 19 in which the different concentrations of the accelerating agent phosphoric acid are added in the effect example 2 can increase the low dielectric material to different degrees (BD). The rate of removal.

Summary of the invention

The invention is further illustrated by the following examples, which are not intended to limit the scope of the invention.

The following polishing liquid is prepared by the squeezing method: a certain amount of abrasive granules is added to the agitator, a certain amount of deionized water and other components are added at a certain rate with stirring and uniformly mixed, and adjusted to the desired pH with KOH or HNO _{3 .} The value is fine.

The percentages of the respective compounds in the following examples are percentages by weight.

Example 1 1% Ce0 ₂ (particle size 30 nm), 0.001% 1-phenyl-5-mercapto-tetrazole, 0.2% diammonium hydrogen phosphate, 0.001% urea peroxide, water balance, pH=2 .

Example 2 2% A1 ₂ 0 ₃ (particle size 20 nm), 0.01% 2-mercapto-benzothiazole, Q.2% pyrophosphoric acid, 0.05% peroxyacetic acid, 0.02% polyacrylic acid (molecular weight 3000), water For the balance, pH = 3.

Example 3 10% TiO ₂ (particle size 150 nm), 0.2% benzimidazole, 0.2% polyphosphoric acid, 0.5% potassium persulfate, 0.02% polyethylene glycol 200 (molecular weight 200), „water is the balance , pH=4.

Example 4 15% doped A1 of SiO ₂ (particle size 30 nm), 0.5% 2-mercaptobenzimidazole, 0.2% ethylenediamine tetramethylene phosphonate, 2% ammonium persulfate, 0.02% polyacrylic acid ( Molecular weight is 10000), Water is the balance, pH = 5.

Example 5 20% coverage of A1 SiQ ₂ (particle size 70 nm), 1% 5-amino-1H-tetrazole, 0.1% phosphoric acid, 0,1 °/. Potassium phosphate, 5% hydrogen peroxide, 0.02% cetyltrimethylammonium bromide, water in the balance, pH=6.

Example 6 10% polymethyl methacrylate (particle size 120 nm), 0.2% benzotriazole, 0.1% aminotrimethylene phosphonic acid (ATMP), 0.1% phosphoric acid, 0.2% hydrogen peroxide, water The balance, Comparative Example 1 10% Si0 ₂ (particle diameter of 100 nm), 0.2% benzotriazole, 0.2% hydrogen peroxide, water as the balance, pH=3.

Effect embodiment 1

The polishing solution 1 10% Si0 ₂ (particle diameter: 100 nm), 0.2% benzotriazole, 0, 2% phosphoric acid, 0.2% hydrogen peroxide, water was the balance, pH = 3.

Polishing solution 2 10% Si0 ₂ (particle size 100 nm), 0.2% benzotriazole, 0.2% potassium pyrophosphate, 0.2% hydrogen peroxide, water. balance, pH=3.

Polishing solution 3 10% Si0 ₂ (particle size 100 nm), 0.2 ° /. Benzotriazole, 0.2% phosphorous acid, 0.2% hydrogen peroxide, water as the balance, pH=3. The polishing solution 4 10% Si0 ₂ (particle diameter: 100 nm), 0.2% benzotriazole, 0.2% trimellitic acid, 0.2% hydrogen peroxide, water as the balance, pH=3.

The polishing liquid 5 10% Si0 ₂ (particle diameter: 100 nm), 0.2% benzotriazole, 0.2% sodium hexametaphosphate, 0.2% hydrogen peroxide, water as the balance, pH=3.

The polishing solution 6 10% Si0 ₂ (particle diameter: 100 nm), 0.2% benzotriazole, 0.2% tripolyphosphoric acid, 0.2% hydrogen peroxide, water as the balance, pH=3.

Slurry 7 10% Si0 ₂ (particle size 100 nm), 0.2% benzotriazole, 0.2% 2-phosphonium bromide-1,2,4-tricarboxylic acid (PBTCA), 0.2% hydrogen peroxide, water For the balance, pH = 3. Polishing solution 8 10% Si0 ₂ (particle size 100nm), 0.2% benzotriazole, Q.2% polyaminopolyether methylene phosphonic acid (PAPEMP), 0.2% hydrogen peroxide, water for the balance , pH=3.

Polishing solution 9 10% Si0 ₂ (particle size 100nm), 0.2% benzotriazole, 0.2% hydroxyethylidene diphosphonic acid (H^DP), 0.2% hydrogen peroxide, water as balance, pH= 3.

The polishing liquid 10 10% Si0 ₂ (particle diameter: 100 nm), 0.2% benzotriazole, 0.2% aminotrimethylene phosphonic acid (ATMP), 0.2% hydrogen peroxide, water was the balance, pH = 3.

Polishing solution 11 10 % Si0 ₂ (particle size 100 nm), 0.2% benzotriazole, 0.2% ethylenediamine tetramethylene phosphonic acid (EDPMP), 0.2% hydrogen peroxide, water balance, pH=3 .

Polishing solution 12 10% Si0 ₂ (particle size 100 nm), 0.2% benzotriazole, 0.2% 2-hydroxydecanoyl acetic acid (HPAA), 0.2% hydrogen peroxide, water balance, pH=3.

Polishing solution 13 10% Si0 ₂ (particle size 100nm), 0.2% benzotriazole, 0.2% diethylenetriamine pentamethylphosphonic acid (DTPMP), 0.2% hydrogen peroxide, water balance, pH= 3.

Using the polishing liquid of Comparative Example 1 and the polishing liquids 1 to 13 of Effect Example 1, the low dielectric material BD (carbon doped silica) was polished at a low polishing pressure (lpsi) at a removal rate such as Figure 1 shows. As can be seen from the figure, in comparison with Comparative Example 1 in which no accelerating agent was added, the polishing liquids 1 to 13 to which the speed increasing agent was added in Effect Example 1 can increase the removal rate of the low dielectric material (BD) to various degrees.

Polishing material: BD (low dielectric material, carbon doped silica); Polishing conditions: IPsi, polishing disc and polishing head speed 70/90 rpm, polishing pad Politex, polishing fluid flow rate 100 ml/min, Logitech PM5 Polisher.

Effect Example 2

The polishing liquid 14 was 10% Si0 ₂ (particle diameter: 100 nm), 0.2% benzotriazole, 0.001% phosphoric acid, 0.2% hydrogen peroxide, water was the balance, pH = 3. The polishing liquid 15 was 10% SiO ₂ (particle diameter: 100 nm), 0.2% benzotriazole, 0.01% phosphoric acid, 0.2% hydrogen peroxide, water was the balance, pH = 3.

The polishing liquid 16 was 10% Si0 ₂ (particle diameter: 100 nm), 0.2% benzotriazole, 0.2% phosphoric acid, 0.2% hydrogen peroxide, water was the balance, pH = 3.

The polishing liquid 17 was 10% Si〇 ₂ (particle diameter: 100 nm), 0.2% benzotriazole, 1% phosphoric acid, 0.2% hydrogen peroxide, water was the balance, pH=3.

Polishing solution 18 10% Si0 ₂ (particle size 100nm), 0.2% benzotriazole, 1.5% phosphoric acid,

0.2% hydrogen peroxide, water is the balance, pH=3.

The polishing solution 19 was 10% Si0 ₂ (particle diameter: 100 nm), 0.2% benzotriazole, 2% phosphoric acid, 0.2% hydrogen peroxide, water was the balance, pH = 3.

Using the polishing liquid of Comparative Example 1 and the polishing liquids 14 to 19 of Effect Example 2, the low dielectric material BD (carbon doped silica) was polished at a low polishing pressure (lpsi) at a removal rate. as shown in picture 2. It can be seen from the figure that compared with Comparative Example 1 in which no accelerating agent is added, the polishing liquids 14 to 19 in which the different concentrations of the accelerating agent phosphoric acid are added in the effect example 2 can increase the low dielectric material to different degrees (BD). The rate of removal.

Polishing material: BD (low dielectric material, carbon-doped silica); Polishing conditions: lPsi, polishing disc and polishing head speed 70/90 rpm, polishing pad Politex, polishing fluid flow rate 100 ml/min, Logitech PM5 Polisher ₀

Effect Example 3

Polishing solution 20 20% Si0 ₂ (particle size 100nm), 0.8% benzotriazole, 2% phosphoric acid, 5% hydrogen peroxide, water for the balance, pH=3

Polishing solution 21 15% Si0 ₂ (particle size 100nm), 0.2% benzotriazole, 0.2% phosphoric acid, 0.2% hydrogen peroxide, water for the balance, pH=3 Polishing solution 22 15% Si0 ₂ (particle size 100nm), 0.2% benzotriazole, 1% phosphoric acid, 0.2% hydrogen peroxide, water for the balance, pH=3

The use of the polishing liquid of the polishing liquid 20 to 22 in the effect example 3 is low for the low dielectric material BD (silica of carbon), metallic copper (Cu), silicon oxide (Teos), and metal tan (Ta). Polishing was carried out at a polishing pressure (lpsi), and the removal rate is shown in Table 1.

As can be seen from Table 1, the polishing liquid 20-22 in the effect example 3 has a higher removal rate than the low dielectric material BD (carbon doped silica), and other materials such as metallic copper (Cu). ), silicon oxide (Teos:), metal tantalum (Ta) also have a higher removal rate.

Table 1 Effect of polishing solution 20-22 on the removal rate of BD (low dielectric material, carbon doped silicon dioxide), metallic copper (Cu), silicon oxide (Teos) and metal tan (Ta)

Polishing material: BD (low dielectric material, carbon doped silica), metallic copper (Cu), silicon oxide (Teos), metal tan (Ta); polishing conditions: lPsi, polishing disc and polishing head speed 70/ 90 rpm, polishing pad Politex, polishing fluid flow rate 100 ml/min, Logitech PM5 Polisher.

The raw materials and reagents used in the present invention are all commercially available products.

Claims

Rights request

A chemical mechanical polishing liquid for polishing a low dielectric material, comprising abrasive particles, a corrosion inhibitor, an oxidizing agent and water, characterized by: further comprising at least one speed increasing agent.

The polishing liquid according to claim 1, wherein the accelerating agent is one or more selected from the group consisting of inorganic phosphoric acid and salts thereof, and organic phosphoric acid and salts thereof.

The polishing liquid according to claim 2, wherein the inorganic phosphoric acid and salts thereof are phosphoric acid, phosphorous acid, pyrophosphoric acid, trimellitic acid, hexametaphosphoric acid, tripolyphosphoric acid, polyphosphoric acid, and a salt of the above acid.

The polishing liquid according to claim 2, wherein the organic phosphoric acid and a salt thereof are 2-phosphonic acid butane-1,2,4-tricarboxylic acid and ethylenediaminetetramethylene. Phosphonic acid, diethylenetriamine pentamethylphosphonic acid, hydroxyethylidene diphosphonic acid, aminotrimethylenephosphonic acid, 2-hydroxyphosphonoacetic acid, polyaminopolyethermethylenephosphonic acid, and the above acids salt.

The polishing liquid according to claim 1, wherein the rate-increasing agent has a weight percentage of 0.001 to 2%.

The polishing liquid according to claim 5, wherein the rate-increasing agent has a weight percentage of 0.01 to 1%.

The polishing liquid according to claim 1, wherein the abrasive particles are silica, alumina, cerium oxide, titanium dioxide, aluminum-doped silica, and aluminum-coated aluminum. Silica or high molecular polymer particles.

The polishing liquid according to claim 1, wherein the abrasive particles have a particle diameter of 20 to 150 nm.

The polishing liquid according to claim 8, wherein the abrasive particles have a particle diameter of 30 to 120 nm.

The polishing liquid according to claim 1, wherein the abrasive particles have a concentration by weight of 1 to 20%.

The polishing liquid according to claim 10, wherein: the abrasive particles are The weight percentage concentration is 2 to 15%.

The polishing liquid according to claim 1, wherein the corrosion inhibitor is an azole compound.

The polishing liquid according to claim 12, wherein the azole compound is benzotriazole, 1-phenyl-5-mercapto-tetrazole, 2-mercapto-benzothiazole, Benzimidazole, 2-mercaptobenzimidazole or 5-amino-1H-tetrazole.

The polishing liquid according to claim 1, wherein the corrosion inhibitor has a concentration by weight of 0.001 to 1%.

The polishing liquid according to claim 14, wherein the corrosion inhibitor has a concentration by weight of 0.01 to 0.5%.

16. The polishing liquid according to claim 1, wherein the oxidizing agent is hydrogen peroxide, urea peroxide, peracetic acid, potassium persulfate or ammonium persulfate.

The polishing liquid according to claim 1, wherein the oxidizing agent has a weight percentage concentration of 0.001 to 5%.

The polishing liquid according to claim 17, wherein the oxidizing agent has a concentration percentage by weight of 0.05 to 2%.

The polishing liquid according to claim 1, wherein the polishing liquid has a pH of 2.0 to 7.0.

The polishing liquid according to claim 19, wherein the polishing liquid has a pH of 2.0 to 5,0.

21. The polishing liquid according to claim 1, wherein: the polishing liquid further contains a surfactant.

The polishing liquid according to claim 21, wherein the surfactant is a nonionic surfactant, a cationic surfactant or an anionic surfactant.