KR20060122188A - Composition of residues removing agent for semiconductor process - Google Patents

Abstract

Provided is a composition for removing the residue remaining on the surface of a substrate after the etching process of semiconductor process without the damaging an under membrane. The composition comprises 0.1-5 wt% of tetramethylammonium hydroxide; 10-40 wt% of water which dissolves the tetramethylammonium hydroxide; 5-85 wt% of a polar solvent which maintains the pH of the solution where tetramethylammonium hydroxide is dissolved in water; 5-50 wt% of a surfactant which is combined with water or the polar solvent by hydrogen bond; and 1-10 wt% of a corrosion inhibitor. Preferably the polar solvent is an amide compound represented by R1-C(=O)-NR3-R2, wherein R1, R2 and R3 are H or an alkyl group.

Description

Composition of residues removing agent for semiconductor process

1 is a state diagram showing general impurities present in a substrate during a semiconductor manufacturing process.

Figure 2 is a photograph showing a state before and after removing the residue as an embodiment of the residue removal liquid composition according to the present invention.

Figure 3 is a photograph showing a state before and after removing the residue as an embodiment of the residue removal liquid composition according to the present invention.

Figure 4 is a graph showing the pH change when water is added to the example of the residue removal liquid composition according to the present invention.

The present invention relates to a residue removal liquid composition for a semiconductor process, and more particularly, to a residue removal liquid composition for removing general impurities remaining on a substrate after an etching process in a semiconductor manufacturing process.

One example of the conventional residue removal liquid composition is composed of alkanolamine and a benzyl alcohol-based corrosion inhibitor including hydroxylamine (Hydroxylamine), of which hydroxylamine (Hydroxylamine) is used to remove the organometallic polymer, Alkyl amines are used to remove photoresist residue.

In addition, another example of the conventional residue removal liquid composition is composed of ammonium fluoride, triethanolamine, and triazole-based corrosion inhibitor, or a polar solvent having ammonium fluoride, alkanolamine, and sulfonic acid, and a benzyl alcohol-based corrosion inhibitor. do.

However, the chemicals of alkanolamines frequently cause corrosion of the lower layer (metal wiring, insulating film, etc.), particularly damage due to galvanic reaction in the case of metal, and have a significant adverse effect on the electrical resistance value. Has a problem in that the yield of semiconductor elements is lowered due to the effect of particles reattached to the substrate surface.

In addition, conventionally, corrosion inhibitors added to prevent corrosion of metal wires and the like to solve the problems of the caulks are mainly used as a substance such as phenol, and thus there is a problem that harms the health of the worker.

Therefore, there is a strong demand for the development of a residue removal liquid composition that does not harm the health of the worker without damaging the underlying film of the photoresist on the substrate.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a residue removal liquid composition for a semiconductor process which dissolves photoresist residues very easily and minimizes corrosion of the underlying film.

Another object of the present invention is to provide an antireflective liquid composition for a semiconductor process that efficiently removes metal-containing impurities, particles, and the like adhering to a substrate surface.

In addition, another object of the present invention is to provide a residue removal liquid composition for a semiconductor process in consideration of the safety of the operator without contaminating the environment.

The residue removal liquid composition for a semiconductor process according to the present invention comprises a tetramethylammonium hydroxide (TMAH), a water in which the TMAH is dissolved, a polar solvent for maintaining the solution in which the TMAH is dissolved at a pH of 4 to 10, the water or the polarity. It is characterized by comprising a nonionic surfactant and a corrosion inhibitor which is hydrogen bond with the solvent. At this time, it is preferable that a small amount of ammonium fluoride or hydrofluoric acid is further included as the reaction promoter.

In the present invention, TMAH is dissolved in water and a polar solvent to dissolve the photoresist residue. The TMAH prevents corrosion of the metal on the substrate because alkanolamine, which was used as a conventional residue removal chemical, reacts with water to generate a hydroxyl group to increase the pH to cause corrosion of the metal on the substrate. Can be.

As the polar solvent, DMAC (N, N-Dimethyl acetamide), DMSO (Dimethyl sulfoxide), DMF (N, N-Dimethylformamide), NMP (N-Methyl-2-Pyrrolidone), PG (Propylene Glycol) can be used. , Amides that have a kind of buffering action, in particular DMAC and DMF, which are stabilized by a resonance structure such as Formula 1 to prevent the solution from becoming basic, are preferred.

That is, according to the Pourbaix Diagram, the pH concentration for minimizing metal corrosion is 4 to 10 (preferably pH 7 to 9). If the metal is out of the above range, the metal is easily corroded. In the phosphorus cleaning process, the chemical is mixed with water to generate a hydroxyl group, so that the metal may be corroded as the pH is increased. Therefore, in order to prevent such corrosion in the past, a process of pre-cleaning using an organic solvent such as isopropyl alcohol (IPA) or methanol was essential, but the polar solvent according to the present invention has a constant pH state even if water is introduced in a subsequent process. Keep it.

A nonionic surfactant is added to effectively penetrate the residue by increasing the wettability, penetration, and dispersibility of the residue removing liquid composition. The nonionic surfactant that can be used in the present invention is RO (CH ₂ CH ₂ O) _n H. (Wherein R is an alkyl, alkylaryl, or aryl group, n is 1 to 10), and may be present in plural numbers depending on the change of R or n.

At this time, in consideration of the degree of foaming, hazards, commercial accessibility, the preferred nonionic surfactant in the present invention is diethylene glycol alkyl ether, one or two or more specified according to the type of alkyl may be used in combination with each other.

In addition, in order to obtain better cleaning power at the interface, at least 4 carbon atoms of the hydrophobic alkyl, diethyleneglycol monobutyl ether (DBDG) and diethyleneglycol dibutyl ether (DBDG) may be preferably applied in the present invention. The nonionic surfactants maximize hydrogen bonding with water or polar solvents to have a relatively long bath life, and foreign substances and various organic oils or metals attached to the surface of the substrate in a deionized water cleaning process. Impurities can be effectively removed.

Corrosion inhibitors are included to prevent corrosion of the underlying film on the substrate, and sulfolene and sulfolene derivatives are preferably used in the present invention. Sulfolene and its derivatives are widely applied to lower layers (metal wiring, insulating layer), etc., and have a wide range of corrosion protection functions in acidic and basic solutions. Formulas 2 and 3 are structural formulas of sulfolene and sulfolene derivatives, respectively.

(이 때, R₁, R₂, R₃, R₄, R₅, R₆는 수소 또는 탄소 하나 이상으로 이루어진 알킬)

(Wherein R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ are hydrogen or alkyl consisting of at least one carbon)

Reaction accelerators are added to quickly remove photoresist and organometallic residues at low temperatures. In the present invention, it is preferable to add ammonium fluoride or fluoric acid, and thus it is possible to apply to a single type and a batch type spin tool.

Meanwhile, the tetramethylammonium hydroxide (TMAH) in each of the aforementioned compositions is 0.1 wt% to 5 wt%, 10 wt% to 40 wt% water, 5 wt% to 85 wt% polar solvent, and nonionic surfactant. It is preferably contained 5% to 50% by weight, 1% to 10% by weight of the corrosion inhibitor, and 0.01% to 2% by weight of the reaction accelerator. In addition, it is preferable that ammonium fluoride or hydrofluoric acid is further contained in an amount of 0.01 parts by weight to 2 parts by weight based on 100 parts by weight of the residue removing liquid composition as a reaction accelerator.

Tetramethylammonium hydroxide (TMAH) is less than 0.1% by weight solubility in the photoresist, when more than 5% by weight is due to the corrosion of the metal. In addition, if the water is added less than 10% by weight can not sufficiently dissolve the added corrosion inhibitors, when added in excess of 40% metal corrosion occurs. If the polar solvent is less than 5% by weight can not inhibit the corrosion of the metal, if it exceeds 85% by weight because of the relatively small amount of added water is less residue removal ability. In addition, the nonionic surfactant is less than 5% by weight of the ability to remove impurities or particles on the surface of the wafer, and when more than 50% by weight the corrosion of the metal is significantly increased and the foaming is severe. And since the corrosion inhibitor is less than 1% by weight is added to the corrosion protection ability, when added more than 10% by weight is due to the residue removal ability. Reaction accelerator was significantly less than 0.01 parts by weight with respect to 100 parts by weight of the residue removal liquid composition, and significantly more than 2 parts by weight of the corrosion of the silicon oxide film or metal proceeded significantly.

Experimental Example Performance Measurement of Nonionic Surfactant

In order to find a more suitable nonionic surfactant for the present invention, the present inventors have found that it is diethyleneglycol monomethyl ether (MDG), diethyleneglycol dimethyl ether (DMDG), diethyleneglycol monoethyl ether (EDG), diethyleneglycol monobutyl ether (BDG), and diethyleneglycol dibutyl ether (DBDG). The performance was tested with the sample.

The diethylene glycol alkyl ether was mixed with water and mixed 1: 1, and then coated on a photoresist-coated substrate to measure the cleaning power, the wetting power, the penetration power, and the degree of foaming.

Surfactants Cleaning power Wetting penetration Foaming degree MDG usually usually usually none DMDG usually usually usually none EDG usually usually usually none BDG Great usually usually none DBDG Great usually usually none

According to Table 1, it can be seen that BDG, DBDG having at least 4 carbon atoms of the hydrophobic alkyl group can be preferably applied in the present invention in order to obtain better cleaning power at the interface.

EXAMPLES Various Examples and Experimental Data According to the Present Invention

The present invention can be implemented in various ways depending on the type and composition ratio of each component. Table 2 shows examples of polar solvents and surfactants among various embodiments of the present invention.

division Composition (wt%) Example 1 DMAC 5-50 TMAH 0.1-2.0 BDG 5-50 Water 10-40 Sulfolene 1 ~ 10 Foshan 0.01 ~ 2 Example 2 DMAC 5-50 TMAH 0.1-2.0 DBDG 5-50 Water 10-40 Sulfolene 1 ~ 10 Foshan 0.01 ~ 2 Example 3 DMAC 5-50 TMAH 0.1-2.0 EDG 5-50 Water 10-40 Sulfolene 1 ~ 10 Foshan 0.01 ~ 2 Example 4 DMAC 5-50 TMAH 0.1-2.0 DEDG 5-50 Water 10-40 Sulfolene 1 ~ 10 Foshan 0.01 ~ 2 Example 5 DMAC 5-50 TMAH 0.1-2.0 MDG 5-50 Water 10-40 Sulfolene 1 ~ 10 Foshan 0.01 ~ 2 Example 6 DMF 5-50 TMAH 0.1-2.0 BDG 5-50 Water 10-40 Sulfolene 1 ~ 10 Foshan 0.01 ~ 2 Example 7 DMF 5-50 TMAH 0.1-2.0 DBDG 5 ~ 50 Water 10-40 Sulfolene 1 ~ 10 Foshan 0.01 ~ 2 Example 8 DMF 5-50 TMAH 0.1-2.0 EDG 5-50 Water 10-40 Sulfolene 1 ~ 10 Foshan 0.01 ~ 2 Example 9 DMF 5-50 TMAH 0.1-2.0 DEDG 5-50 Water 10-40 Sulfolene 1 ~ 10 Foshan 0.01 ~ 2 Example 10 DMF 5-50 TMAH 0.1-2.0 MDG 5-50 Water 10-40 Sulfolene 1 ~ 10 Foshan 0.01 ~ 2

The residue removal liquid compositions according to each of the above examples showed excellent residue removal ability. FIG. 4 shows the residue on the wafer having the Ti / Al-Cu / TiN / BPSG stack as the residue removal liquid composition of Example 1 of Table 1 at room temperature. SEM image showing the state before and after removing for 5 minutes at, Figure 3 is removed from the residue on the wafer having a Ti / Al-Cu / TiN / BSPSG stack with a residue removal liquid composition of Example 5 of Table 1 for 5 minutes at room temperature SEM image showing the state before and after, according to which it can be seen that the impurities on the wafer has been removed.

In addition, the residue removal liquid composition according to each of the above examples was almost no change in pH even if water is added, Figure 2 is a graph showing the pH change when water is mixed in each of the embodiments of Table 1, according to this, Even if the ratio of water is increased to 90%, the pH is constant at about 8.5, it can confirm the buffering role of the polar solvent according to the present invention.

 On the other hand, in order to measure the degree of corrosion of the bottom film other than impurities of the residue removal liquid composition according to each of the examples after treating the substrate with the composition according to Example 10 for 10 minutes, washed with water and dried with nitrogen gas before and after The change of the film thickness of was measured. Table 3 summarizes the film thickness change of the underlying film material.

Board Al Cu Ti FSG BPSG SOG Etch Rate (Å / min) 5 or less 5 or less 5 or less 5 or less 5 or less 5 or less

According to Table 3, it can be seen that the residue removal liquid composition according to the present invention has almost no corrosive effect on the lower layer other than impurities.

Thus, the present invention has been described mainly based on the above embodiments, many other possible modifications and variations can be made without departing from the spirit and scope of the invention. For example, the addition of a tolerant material that does not significantly change the effect of the present invention, the specification of the composition ratio, etc. will be a change that can be easily derived by those skilled in the art.

The residue removal liquid composition for a semiconductor process according to the present invention, firstly, easily dissolves the photoresist residue on the substrate, minimizes corrosion of the lower layer, and secondly, effectively removes metal impurities and foreign substances, and thirdly, environmental pollution It does not cause the effect.

The scope of the above-described invention is defined in the following claims, and is not bound by the description in the text of the specification, all modifications and variations belonging to the equivalent scope of the claims will fall within the scope of the present invention.

Claims (7)

Tetramethylammonium hydroxide (TMAH); Water to dissolve the TMAH; Polar solvent to maintain the solution dissolved TMAH at pH 4 to 10; Nonionic surfactants which hydrogen bond with the water or the polar solvent; And A residue removal liquid composition for a semiconductor process, comprising a corrosion inhibitor. According to claim 1, The tetramethylammonium hydroxide (TMAH) is 0.1 to 5% by weight, the water is 10% to 40% by weight, the polar solvent is 5% to 85% by weight, the nonionic surfactant is 5% by weight to 50% by weight, and the corrosion inhibitor is contained in 1% by weight to 10% by weight (sum of the composition ratio of each composition is 100% by weight), the residue removal liquid composition for a semiconductor process. The method of claim 2, Ammonium fluoride or hydrofluoric acid as a reaction accelerator, 0.01 parts by weight to 2 parts by weight based on 100 parts by weight of the residue removal liquid composition, characterized in that the residue removal liquid composition for a semiconductor process. The method of claim 3, wherein The polar solvent is a residue removal liquid composition for a semiconductor process, characterized in that the amide of the following formula.

(Wherein R ₁ , R ₂ and R ₃ are hydrogen or an alkyl group consisting of at least one carbon) The method of claim 4, wherein The amide is a residue removal liquid composition for a semiconductor process, characterized in that the DMMC (DMAC) or DMF (DMF). The method of claim 5 The nonionic surfactant is diethylene glycol alkyl ether (wherein alkyl has 1 to 10 carbon atoms) residue removal liquid composition for a semiconductor process. The method of claim 6, The corrosion inhibitor is a sulfolane or a residue removal liquid composition for a semiconductor process, characterized in that the sulfon derivative of the following formula.

(Wherein R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ are hydrogen or alkyl consisting of at least one carbon)

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