TWI444460B - Slurry composition - Google Patents

Description

Slurry composition

This invention relates to a composition, and more particularly to a slurry composition.

In a very large integrated circuit (VLSI) process, a chemical mechanical polishing (CMP) process provides global planarization of the wafer surface, especially when the semiconductor process enters sub-micron. After the field, chemical mechanical grinding is an indispensable process technology.

In the manufacturing process of a semiconductor element (for example, a step of fabricating a shallow trench isolation structure), it is often encountered to simultaneously polish a tantalum nitride layer and a tantalum oxide layer. In general, different slurry compositions are suitable for different layers. In order to control the removal ratio of tantalum nitride to cerium oxide to be greater than 1, equal to 1 or less than 1, it is necessary to formulate at least three polishing composition having different compositions. However, since space is required to store different components, storage costs are increased and management is also inconvenient.

In view of the above, the present invention provides a polishing liquid composition which can effectively control the removal ratio of tantalum nitride to cerium oxide without changing its composition to change only its component content.

The invention provides a polishing liquid composition, comprising abrasive particles, polyethylene Glycols, solvents, and cation additives.

In an embodiment of the invention, the cation additive is an ammonium salt represented by the formula (1): RNR' ₃ ⁺ X ^- (1)

Wherein R is a linear or branched alkyl group having 1 to 18 carbon atoms or an aromatic group having 2 to 10 carbon atoms, and R' is hydrogen and has 1 to 18 carbons. An alkyl group of an atom or an aromatic group having 2 carbons to 10 carbon atoms, each R' may be the same or different, and X ^- is a hydroxide or a halogen anion or acetate.

In one embodiment of the invention, the ammonium salt comprises tetramethylammonium hydroxide, benzyltrimethylammonium hydroxide or methylammonium hydroxide.

In an embodiment of the invention, the cation additive comprises a titanium salt.

In an embodiment of the invention, the titanium salt comprises titanium trichloride or titanium tetrachloride.

In an embodiment of the invention, the cation additive comprises a phosphonium salt.

In an embodiment of the invention, the onium salt comprises cerium nitrate or cerium nitrate.

In one embodiment of the invention, the cationic additive is present in an amount from about 1 ppm to about 500 ppm.

In an embodiment of the invention, the abrasive particles comprise a nano sol, a smoked cerium oxide, aluminum oxide, a composite nanoparticle having cerium oxide on the surface, or a mixture of any two.

In one embodiment of the invention, the abrasive particles are present in an amount from about 0.1% to about 25% by weight.

In one embodiment of the invention, the polyethylene glycol is present in an amount from about 1 ppm to about 2,000 ppm.

In one embodiment of the invention, the polyethylene glycol has an average molecular weight of about 4000 g/mol or less.

In an embodiment of the invention, the solvent comprises water.

In an embodiment of the invention, the slurry composition has a pH in the range of 2 to 6.

Based on the above, the polishing composition of the present invention can effectively control the removal ratio of tantalum nitride to cerium oxide without changing its composition and only changing its component content, thereby reducing storage cost and making management easier. .

The above described features and advantages of the present invention will be more apparent from the following description.

The slurry composition of the present invention comprises abrasive particles, polyethylene glycol, a solvent, and a cationic additive. The polishing liquid composition of the invention is suitable for the chemical mechanical polishing process, and when the tantalum nitride layer and the tantalum oxide layer are simultaneously polished, the removal ratio of the tantalum nitride to the tantalum oxide can be controlled by adjusting the content ratio between the components. (or selection ratio) is greater than 1, equal to 1 or less than 1. Hereinafter, examples and contents of each component will be separately described.

The abrasive particles include a nano sol, a smoked cerium oxide, aluminum oxide, a composite nanoparticle having cerium oxide on the surface, or a mixture of any two. Grinding The particles have an average particle size ranging from about 80 nm to about 150 nm. In one embodiment, the abrasive particles are present in an amount from about 0.1% to about 25% by weight. In another embodiment, the abrasive particles are present in an amount from about 5% to about 9% by weight.

The polyethylene glycol has an average molecular weight of about 4000 g/mol or less. In one embodiment, the polyethylene glycol is present in an amount from about 1 ppm to about 2,000 ppm. In another embodiment, the polyethylene glycol is present in an amount from about 10 ppm to about 1,000 ppm. In yet another embodiment, the polyethylene glycol is present in an amount from about 50 ppm to about 500 ppm.

The solvent can be water, such as deionized water. Further, the polishing liquid composition may also include other additives such as an acid-base adjusting agent and a complexing agent. The pH of the slurry composition ranges from about 2 to 6, such as three.

The cation additive may be an ammonium salt represented by the formula (1): RNR' ₃ ⁺ X ^- (1)

Wherein R is a linear or branched alkyl group having 1 to 18 carbon atoms or an aromatic group having 2 to 10 carbon atoms, and R' is hydrogen and has 1 to 18 carbons. An alkyl group of an atom or an aromatic group having 2 carbons to 10 carbon atoms, each R' may be the same or different, and X ^- is a hydroxide or a halogen anion or acetate. In one embodiment, the ammonium salt comprises tetramethylammonium hydroxide, benzyltrimethylammonium hydroxide or methylammonium hydroxide.

Further, the cationic additive may be a titanium salt such as titanium trichloride or titanium tetrachloride. The cationic additive may also be a phosphonium salt such as cerium nitrate or cerium nitrate. In one embodiment, the cationic additive is present in an amount from about 1 ppm to about 500 ppm. In another embodiment, the cationic additive is present in an amount from about 25 ppm to about 200 ppm.

In the polishing composition of the present invention, the action of the polyethylene glycol is to inhibit the removal rate of cerium oxide, and the effect of the cationic additive is to reduce the inhibitory effect of polyethylene glycol on cerium oxide, and Inhibitory effect. When the content of the cation additive exceeds a certain value, the inhibitory effect of polyethylene glycol on cerium oxide disappears. Therefore, the removal ratio of tantalum nitride to ruthenium oxide can be made greater than 1, equal to 1, or less than 1, by adjusting the content of polyethylene glycol and the cation additive.

In the following, actual example tests will be carried out in which the chemical mechanical polishing machine and examples used are set as follows.

Chemical mechanical polishing machine model: Mirra 340 (Applied Materials)

Substrate to be polished: a tantalum nitride substrate and a tetraethyl orthosilicate (TEOS) ruthenium oxide substrate.

Polishing pad: Politex (product name, manufactured by Dow Chemical Co., Ltd.)

Grinding head pressure: 1.8 psi

Relative rotation speed of polishing pad and grinding head: 93rpm to 87rpm

Grinding time: 60 seconds

Example 1

1). The slurry composition was 8% nano bismuth sol, 50 ppm polyethylene glycol and 25 ppm tetramethylammonium hydroxide (pH = 3) were added to remove the tantalum nitride substrate and the ruthenium oxide substrate.

2). The slurry composition is 8% nano sputum sol added with 50 ppm polyethylene glycol and 100 ppm tetramethylammonium hydroxide (pH = 3) for nitrogen Removal of the ruthenium substrate and the ruthenium oxide substrate.

3). The slurry composition was 8% nano bismuth sol, 50 ppm polyethylene glycol and 200 ppm tetramethylammonium hydroxide (pH = 3) were added to remove the tantalum nitride substrate and the ruthenium oxide substrate.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a graph showing the relationship between the content of tetramethylammonium hydroxide of the polishing composition of Example 1 and the removal rate of a tantalum nitride substrate and a ruthenium oxide substrate. As shown in FIG. 1, when the content of tetramethylammonium hydroxide increases, the removal rate of the tantalum nitride substrate decreases and the removal rate of the tantalum oxide substrate increases, and the removal ratio of tantalum nitride to tantalum oxide changes from greater than 1 to less than 1.

Example 2

The slurry composition was a 5% nano cerium sol, 500 ppm polyethylene glycol and 50 ppm tetramethylammonium hydroxide (pH = 3), and the cerium nitride substrate and the cerium oxide substrate were removed.

In Example 2, the removal rates of the tantalum nitride substrate and the hafnium oxide substrate were both 348 angstroms/min, and thus the removal ratio of tantalum nitride to yttrium oxide was 1.

Example 3

1). The slurry composition was a 9% nano cerium sol, 100 ppm of polyethylene glycol and 25 ppm of cerium nitrate (pH = 3), and the cerium nitride substrate and the cerium oxide substrate were removed.

2). The slurry composition was a 9% nano cerium sol, 100 ppm of polyethylene glycol and 100 ppm of cerium nitrate (pH = 3), and the cerium nitride substrate and the cerium oxide substrate were removed.

3). The slurry composition was a 9% nano cerium sol added with 100 ppm polyethylene glycol and 200 ppm cerium nitrate (pH = 3), and the cerium nitride substrate and the cerium oxide substrate were removed.

Figure 2 is a graph showing the relationship between the nitrile nitrate content of the polishing composition of Example 3 and the removal rate of the tantalum nitride substrate and the hafnium oxide substrate. As shown in FIG. 2, when the content of cerium nitrate increases, the removal rate of the cerium nitride substrate decreases and the removal rate of the cerium oxide substrate increases, and the removal ratio of cerium nitride to cerium oxide becomes greater than 1 to become equal to 1 or less. 1.

Example 4

1). The slurry composition was a 9% nano cerium sol, and 150 ppm of polyethylene glycol and 50 ppm of titanium trichloride (pH = 3) were added to remove the tantalum nitride substrate and the ruthenium oxide substrate.

2). The slurry composition was a 9% nano cerium sol, 150 ppm of polyethylene glycol and 150 ppm of titanium trichloride (pH = 3), and the cerium nitride substrate and the cerium oxide substrate were removed.

3). The slurry composition was a 9% nano cerium sol, and 150 ppm of polyethylene glycol and 250 ppm of titanium trichloride (pH = 3) were added to remove the tantalum nitride substrate and the ruthenium oxide substrate.

Figure 3 is a graph showing the relationship between the content of titanium trichloride in the slurry composition of Example 4 and the removal rate of the tantalum nitride substrate and the tantalum oxide substrate. As shown in FIG. 3, when the content of titanium trichloride is increased, the removal rate of the tantalum nitride substrate is lowered and the removal rate of the tantalum oxide substrate is increased, and the removal ratio of tantalum nitride to the tantalum oxide is changed from more than 1 to less than 1.

In summary, in the polishing composition of the present invention, the content of the polyethylene glycol and the cation additive can be adjusted so that the content of the abrasive particles, the solvent component and the content thereof are not changed. The removal ratio of cerium oxide is greater than 1, equal to 1, or less than one. In other words, the slurry composition of the present invention can change only its component content without changing its composition. Under the effective control of the removal ratio of tantalum nitride to cerium oxide, it can reduce storage costs and make management easier.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the invention, and any one of ordinary skill in the art can make some modifications and refinements without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a graph showing the relationship between the content of tetramethylammonium hydroxide of the polishing composition of Example 1 and the removal rate of a tantalum nitride substrate and a ruthenium oxide substrate.

Figure 2 is a graph showing the relationship between the nitrile nitrate content of the polishing composition of Example 3 and the removal rate of the tantalum nitride substrate and the hafnium oxide substrate.

Figure 3 is a graph showing the relationship between the content of titanium trichloride in the slurry composition of Example 4 and the removal rate of the tantalum nitride substrate and the tantalum oxide substrate.

Claims (11)

A polishing liquid composition comprising: abrasive particles; polyethylene glycol; a solvent; and a cationic additive, wherein the abrasive particles are contained in an amount of 0.1% by weight to 25% by weight, and the polyethylene glycol is present in an amount of 1 ppm to 2,000 ppm, and the content of the cationic additive is from 1 ppm to 500 ppm. The slurry composition according to claim 1, wherein the cation additive is an ammonium salt represented by the formula (1): RNR' ₃ ⁺ X ^- (1) wherein R is 1 carbon to 18 a linear or branched alkyl group of carbon atoms or an aromatic group having 2 carbons to 10 carbon atoms, R' is hydrogen, an alkyl group having 1 to 18 carbon atoms or 2 carbons An aromatic group of ~10 carbon atoms, each R' may be the same or different, and X ^- is a hydroxide or a halogen anion or acetate. The slurry composition of claim 2, wherein the ammonium salt comprises tetramethylammonium hydroxide, benzyltrimethylammonium hydroxide or methylammonium hydroxide. The slurry composition of claim 1, wherein the cationic additive comprises a titanium salt. The slurry composition of claim 4, wherein the titanium salt comprises titanium trichloride or titanium tetrachloride. The slurry composition of claim 1, wherein the cation additive comprises a phosphonium salt. The slurry composition of claim 6, wherein the onium salt comprises cerium nitrate or cerium nitrate. The slurry composition according to claim 1, wherein the abrasive particles comprise a nano sol, a smoked cerium oxide, aluminum oxide, a composite nanoparticle having cerium oxide on the surface, or a mixture of any two. The slurry composition according to claim 1, wherein the polyethylene glycol has an average molecular weight of 4000 g/mol or less. The slurry composition of claim 1, wherein the solvent comprises water. The slurry composition of claim 1, wherein the slurry composition has a pH in the range of 2 to 6.