KR20220063535A - COMPOSITION FOR PLATING COPPER AND METHOD OF plating COPPER and substrate formed BY USING THE SAME - Google Patents

Abstract

The present invention relates to a copper plating composition, a copper plating method using the same, and a substrate manufactured thereby. By including a compound of a specific structure as a leveler, as openings such as vias and the like formed in the substrate to be plated are secured, no voids are generated inside the vias and the like during plating, and excellent flatness can be exhibited even when plating at a high speed. The present invention provides the copper plating composition including at least one leveler of chemical formula 1 and chemical formula 2.

Description

A copper plating composition, a copper plating method using the same, and a substrate manufactured thereby

The present invention relates to a copper plating composition, a copper plating method using the same, and a substrate manufactured by the same.

With the trend of miniaturization of electronic components such as semiconductor devices and PCBs, high-density and high-integration technologies are required. In particular, for high density and high integration of semiconductor devices, it is important to select a wiring material that has low resistance and can implement a fine line width, etc. The frequency of using this low copper as a wiring material is increasing. Copper has better electrical and thermal conductivity than gold or aluminum, and since it does not form an intermetallic compound compared to gold or aluminum, it has the advantage that reliability at high temperatures can be improved when wiring is formed using copper.

However, in forming a pattern using only copper or manufacturing a substrate, unlike metals such as aluminum, it is difficult to process by RIE (Reactive Ion Etching), so they avoid using copper as a wiring material. . Accordingly, a via hole, a through-hole, a trench, or a through electrode (hereinafter, referred to as a 'via hole, etc.') having a shape of a predetermined pattern on a substrate such as a silicon wafer and/or a PCB. .) and the like, and then filling the copper with a method such as electroplating to form a copper structure is used. In the case of copper plating in this way, if copper is deposited inside via holes, etc., defects may occur due to clogging of openings such as via holes before copper plating is completed inside the via holes. many.

In addition, although it is necessary to improve the plating rate to improve process efficiency, the higher the plating rate, the higher the possibility of the defect, and the flatness after plating is also deteriorated. Specifically, the plating rate of the plating process is proportional to the current density applied to the plating solution, but when the current density is high, the metal deposition process on the surface of the substrate is locally deviated from the normal state, and the metal film to be plated is partially Abnormal growth is caused by excessive growth or insufficient growth. Accordingly, there is a problem in that the surface flatness after plating is lowered, so that a sufficient contact area with the external connection body cannot be provided.

In relation to this, Korean Patent Laid-Open No. 10-2010-0038576 discloses a composition for copper plating in which flatness is improved by using a disulfide compound as an accelerator, but there is a limit to improving flatness when the plating speed is increased. there is.

Accordingly, it is necessary to develop a copper plating composition having improved plating performance even when plating is performed at a high speed by securing openings such as vias formed in the substrate.

Republic of Korea Patent Publication No. 10-2010-0038576

The present invention is to improve the problems of the prior art, a copper plating composition with improved plating performance even when plating at a high speed by securing openings such as vias formed in a substrate, a copper plating method using the same, and manufacturing by the same An object of the present invention is to provide a substrate.

However, the problems to be solved by the present application are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, the present invention provides a copper plating composition comprising at least one leveler selected from Chemical Formulas 1 and 2.

In addition, the present invention provides a copper plating method using the copper plating composition and a substrate formed by the method.

According to the present invention, since openings such as vias formed in the substrate to be plated are secured, voids are not generated inside the vias during plating, and excellent flatness is exhibited even when plated at high speed.

The present invention relates to a copper plating composition, a copper plating method using the same, and a substrate manufactured by the same. By including a compound having a specific structure as a leveler, openings such as vias formed in a substrate to be plated can be secured, Accordingly, during plating, defects such as voids do not occur inside vias, etc., and plating can be performed uniformly, and excellent flatness is exhibited even when plating at high speed.

In the present invention, “plating” and “deposition” may be used in substantially corresponding meanings, and are not limited to a specific form.

In the present invention, “plating” may be for manufacturing all substrates, wirings, and/or electrodes used in manufacturing electronic products, and in particular, it is applied to boards, wirings and electrodes used in manufacturing semiconductor devices or PCBs. may be, but is not limited thereto. The present invention may relate to plating of via holes, through-holes, trenches or substrates comprising through-electrodes, wirings and/or electrodes.

In the present specification, when a part "includes" a certain component, this means that other components may be further included, rather than excluding other components, unless otherwise stated.

In the present specification, the term "substitution" means that a hydrogen atom bonded to a carbon atom of a compound is changed to another substituent, and the position to be substituted is not limited as long as the position at which the hydrogen atom is substituted, that is, a position where the substituent is substitutable, 2 In the case of more than one substitution, two or more substituents may be the same as or different from each other.

In the present invention, the thickness of the plating is not particularly limited, but may be 1 to 1000 μm .

The plating of the present invention may be electrolytic plating, and may be performed by applying a current in a current density range of 1 ASD to 20 ASD (Ampere per Square Decimetre). According to the present invention, flatness can be ensured even during plating at such a high speed.

<Copper Plating Composition>

The copper plating composition of the present invention is characterized in that it includes at least one of the following Chemical Formulas 1 and 2 as a leveler. In addition, the copper plating composition of the present invention further comprises at least one of (A) a copper salt, (B) an inorganic acid, (C) a chloride ion, (D) a reduction reaction accelerating accelerator, (E) a copper ion migration inhibitor, and water. may include In addition, within a range that does not impair the object of the present invention, it may further include a known additive.

leveler

The copper plating composition of the present invention may include a cation-dissolving nitrogen-containing compound or a salt thereof as a leveler, and may preferably include at least one compound or a salt thereof of the following Chemical Formulas 1 and 2 below.

[Formula 1]

[Formula 2]

In Formula 1 and Formula 2,

R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are each independently hydrogen (H), an alkyl group, a glycol ether group, or —NaSO ₃ may be a substituent including, preferably hydrogen (H), an alkyl group having 1 to 3 carbon atoms, a glycol ether group having 1 to 10 carbon atoms, or -CH ₂ -C ₆ H ₅ -NaSO ₃ It may be.

R ⁶ and R ¹² may each independently be a substituent including nitrogen (N), halogen, or sulfur (S), and preferably, -NH-Y ₁ , -N-2Y ₂ , -Cl or - It may be NaSO ₃ .

Y ₁ may be a phenyl group unsubstituted or substituted with an alkyl group having 1 to 3 carbon atoms or an alkoxy group having 1 to 4 carbon atoms.

The Y ₂ is an alkyl group having 1 to 3 carbon atoms.

In the present invention, a "salt" of a compound may be in any chemically acceptable salt form for the compound. Examples of the salt include, but are not limited to, a form in which one or more hydrogen ions (H + ) are bonded to or separated from the compound, or a halogen salt.

The compound of Formula 1 or a salt thereof may be a compound having any one of the structures of Formulas 1-1 to 1-4 below.

[Formula 1-1]

[Formula 1-2]

[Formula 1-3]

[Formula 1-4]

In addition, the compound of Formula 2 or a salt thereof may be a compound having any one of the structures of Formulas 2-1 to 2-3 below.

[Formula 2-1]

[Formula 2-2]

[Formula 2-3]

The leveler of the present invention serves to improve the uniformity and flatness of the copper plating film by adsorbing to a portion of the plating film having a high current density in the electrolytic copper plating process to suppress the reduction of copper ions. The leveler having a specific structure of the present invention has a polarity in the structural formula, and thus has a property of suppressing copper (Cu) deposition. That is, metal deposition can be suppressed by selectively adsorbing to the edge of the pattern or the convex portion of the metal surface where the electric field lines are concentrated due to the polarity in the compound. Accordingly, since openings such as vias formed in the substrate to be plated are secured, voids are not generated inside the vias during plating, and excellent flatness is exhibited even when plated at high speed. Specifically, by imparting a (+) charge to the nitrogen atom, it is possible to prevent the deposition of copper in the opening portions such as vias formed in the substrate to be plated, thereby preventing the formation of voids in vias, etc., thereby improving plating performance. can do it

In addition, in the formula structure, it exhibits the ability to inhibit metal deposition by a structure in which three aryl groups of phenyl or naphthyl are connected. That is, the structure in which three aryl groups of phenyl or naphthyl are connected is a planar structure, and when adsorbed on a metal surface, molecular alignment is facilitated and the structure is densely adsorbed. In addition, compared to the structure of the conventional leveler, since it is a low molecular material, the movement speed in the plating solution is high, and it has the advantage of maximizing the selective suppression effect by rapidly adsorbing and desorbing to the metal surface.

In the present invention, the leveler may be included in an amount of 0.1 mg/L to 100 mg/L, more preferably 1 mg/L to 30 mg/L, based on the total weight of the copper plating composition, and It is desirable to maximize the same effect.

(A) copper salt

The copper salt of this invention serves as a supply source of copper ions. The copper salt may be reduced to copper metal through an electrochemical reaction and precipitated to form solder bumps, metal wirings for damascene and TSV, via holes and trenches on a substrate.

The copper salt is not limited as long as it is a soluble copper salt capable of dissociating in the composition to provide copper ions. For example, 1 selected from the group consisting of copper sulfate, copper carbonate, copper oxide, copper chloride, copper fluoroborate, copper nitrate, copper phosphate, copper methanesulfonate, copper ethanesulfonate, copper propanolsulfonate, copper acetate, and copper citrate More than one species can be mentioned. Preferably, it may include copper sulfate hydrate, and most preferably copper sulfate pentahydrate (CuSO ₄ ·5H ₂ O).

The content of the copper salt may be 10 g/L to 300 g/L, preferably 50 g/L to 200 g/L, based on the total weight of the copper plating composition. If the copper salt is less than 10 g/L, copper precipitation is insignificant, and foreign substances are included in the plating film, which may decrease adhesion to the substrate. there is.

(B) mineral acid

The inorganic acid of the present invention may be included to impart electrical conductivity. Specifically, the inorganic acid may be dissolved in a solution to increase the conductivity of the copper plating composition.

The inorganic acid may be at least one selected from the group consisting of sulfuric acid, acetic acid, methanesulfonic acid, ethanesulfonic acid, boric acid, and fluoroboric acid, and may preferably include sulfuric acid.

The content of the inorganic acid may be 20 g/L to 400 g/L, preferably 30 g/L to 150 g/L, based on the total weight of the copper plating composition. If the acid is less than 20 g / ℓ, there is a fear that the efficiency may be lowered due to low electrical conductivity. Conversely, if the acid exceeds 400 g / ℓ, a problem may occur in plating quality due to excessive reaction.

(C) chloride ions

The chloride ion of the present invention serves to activate the plating inhibitor, and may be included to increase the plating speed when used alone.

The chloride ion may include sodium chloride (NaCl) or hydrochloric acid (HCl), and preferably includes hydrochloric acid (HCl).

In the present invention, the chloride ion content may be included in the range of 5 mg/L to 200 mg/L, preferably 20 mg/L to 150 mg/L, based on the total weight of the copper plating composition. When the acid is less than 5 mg/L, the plating inhibitory effect is lowered and the desired plating speed cannot be maintained.

(D) reduction reaction accelerating accelerator

The reduction reaction accelerating accelerator of the present invention serves to increase the copper plating rate.

The reduction reaction accelerator is bis-(3-sulfopropyl) disulfide (SPS)), mercaptoethane sulfonic acid, 3-mercapto-1-propane sulfuric acid (3 -mercapto-1-propanesulfonic acid (MPSA)) and 3-N,N-dimethylaminodithiocarbamoyl-1-propane sulfuric acid (3-N,N-dimethlyaminodithiocarbamoyl-1-propanesulfonic acid (DPS)) It may be at least one selected type, and preferably bis-(3-sulfopropyl) disulfide (SPS) may be included.

The content of the reduction reaction accelerating accelerator of the present invention may be 0.1 mg/L to 100 mg/L, preferably 1 mg/L to 30 mg/L, based on the total weight of the copper plating composition. In the case of less than 0.1 mg/L of the accelerator, the efficiency of the accelerator is low and there is a fear that the plating speed may be lowered.

(E) copper ion migration inhibitor

The copper ion migration inhibitor of the present invention serves to control the rate at which copper is filled by controlling the copper reduction rate by inhibiting the movement of copper ions.

The copper ion migration inhibitor may be at least one selected from the group consisting of polyethylene glycol (PEG), polypropylene glycol (PPG), and copolymers thereof, preferably polyethylene glycol (polyethylene glycol). glycol (PEG)). Examples of the copolymer of polyethylene glycol and polypropylene glycol include PEG-PPG-PEG triblock copolymer, PEG-PPG diblock copolymer, PPG-PEG-PPG triblock copolymer, PEG-PPG-PEGPPG tetrablock copolymer and the like. The molecular weight of the copper ion migration inhibitor may be in the range of about 100 to 100,000.

The content of the copper ion migration inhibitor is 20 mg/L to 5,000 mg/L, preferably 50 mg/L to 3,000 mg/L. When the inhibitor is less than 20 mg/ℓ, the efficiency of the copper ion migration inhibitor copper ion migration inhibitor is low, so there is a fear that the plating speed may be excessively increased. can

(F) water

The water included in the copper plating composition of the present invention may be deionized water for a semiconductor process, and preferably 18 MΩ/cm or more of the ionized water may be used. In addition, the water may be included in the remaining amount, the remaining amount means the remaining amount such that the weight of the total composition including the essential components and other components included in the copper plating composition of the present invention is 100% by weight .

<Copper plating method using copper plating composition and substrate prepared accordingly>

The present invention includes a copper plating method using the above-described copper plating composition, and includes an integral substrate manufactured or formed according to the copper plating composition or the copper plating method.

A known technique may be applied to the copper plating method and the substrate of the present invention, except that the above-described copper plating composition is used.

Specifically, the copper plating method of the present invention comprises:

a) providing a copper plating composition of the present invention;

b) immersing a substrate including a via hole, a through-hole, a trench, or a through electrode in the copper plating composition.

In the present invention, the substrate may be at least one of a silicon wafer substrate and a PCB substrate, but is not limited thereto.

Hereinafter, the present invention will be described in more detail through examples. However, the following examples are provided to illustrate the present invention in more detail, and the scope of the present invention is not limited by the following examples.

Examples 1 to 6 and Comparative Examples 1 to 4: Preparation of copper plating composition

A copper plating composition was prepared according to the components and composition ratios shown in Table 1 below.

(A) Copper sulfate pentahydrate (CuSO4·5H2O)
(g/l) (B) sulfuric acid
(g/l) (C) hydrochloric acid
(mg/ℓ) (D) SPS
(mg/ℓ) (E) polyethylene glycol (molecular weight: 4000)
(g/l) Formula 2-3
(mg/ℓ) Formula 1-1
(mg/ℓ) Formula 1-2
(mg/ℓ) plating speed
(ASD) Janus Green B* Diazine Black Example 1 150 100 50 10 One 10 10 Example 2 100 100 50 10 One 50 15 Example 3 150 50 50 10 One 10 10 Example 4 150 100 100 10 One 10 20 Example 5 150 100 100 10 One 10 20 Example 6 150 100 100 10 One 10 20 Comparative Example 1 150 100 50 10 One 10 Comparative Example 2 150 100 50 10 One 0.05 10 Comparative Example 3 150 100 100 10 One 10 20 10 Comparative Example 4 150 100 100 10 One 10 20 10

* Janus Green B: Diazine BlackDiazine Black

Experimental Example 1: Evaluation of flatness according to plating speed

In this experimental example, copper plating was performed to a thickness of 30 μm or more on a patterned wafer (Silicon wafer for semiconductor). Copper electroplating was performed through current application, and current was applied in a current density range of 1 ASD to 20 ASD (Ampere per Square Decimetre).

For the copper plating result, the profile of the scanned copper plating film is checked using a surface profiler (Olympus OLS 5000 Model). Flatness was expressed by measuring the difference in the thickness of the copper plating film from the highest point to the lowest point on the pattern.

Specifically, for the copper plating result plated as described above, the profile of the scanned copper plating film was checked using the surface profiler, and in the case of the plating film, the copper plating was performed in a convex shape in the middle of the pattern upper part. After a film was formed, the difference in the thickness of the copper plating film from the highest point to the lowest point on the pattern was measured, and it is shown in Table 2 based on the following criteria.

○: Excellent (flatness < 2.0㎛)

△: good (2.0㎛ ≤ flatness < 5.0㎛)

X: Poor (5.0㎛ ≤ flatness)

Flatness (㎛) Example 1 ○ Example 2 ○ Example 3 ○ Example 4 ○ Example 5 ○ Example 6 ○ Comparative Example 1 Ⅹ Comparative Example 2 Ⅹ Comparative Example 3 Ⅹ Comparative Example 4 Ⅹ

Claims (11)

A copper plating composition comprising at least one compound of the following Chemical Formulas 1 and 2 or a salt thereof as a leveler:
[Formula 1]

[Formula 2]

In Formula 1 and Formula 2,
R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are each independently hydrogen (H), an alkyl group having 1 to 3 carbon atoms, 1 to carbon atoms A glycol ether group of 10, or -CH ₂ -C ₆ H ₅ -NaSO ₃ It is,
R ⁶ and R ¹² are each independently -NH-Y ₁ , -N-2Y ₂ , -Cl or -NaSO ₃ And
Wherein Y ₁ is a phenyl group unsubstituted or substituted with an alkyl group having 1 to 3 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms,
The Y ₂ is an alkyl group having 1 to 3 carbon atoms.
The copper plating composition according to claim 1, wherein the compound of Formula 1 or a salt thereof is at least one selected from the following structures of Formulas 1-1 to 1-4.
[Formula 1-1]

[Formula 1-2]

[Formula 1-3]

[Formula 1-4]

The copper plating composition according to claim 1, wherein the compound of Formula 2 or a salt thereof is at least one selected from compounds having structures of Formulas 2-1 to 2-3 below.
[Formula 2-1]

[Formula 2-2]

[Formula 2-3]

The copper plating composition of claim 1, wherein the leveler is included in an amount of 0.1 mg/L to 100 mg/L based on the total weight of the copper plating composition.
The method according to claim 1,
(A) copper salts;
(B) inorganic acids;
(C) chloride ions;
(D) a reduction reaction accelerating accelerator; and
(E) copper ion migration inhibitor
Copper plating composition further comprising one or more of.
The copper plating composition of claim 1, further comprising water.
6. The method of claim 5,
The reduction reaction accelerator is bis- (3-sulfopropyl) disulfide (bis (3-sulfopropyl) disulfide (SPS)), mercaptoethane sulfonic acid, 3-mercapto-1-propane sulfuric acid (3 -mercapto-1-propanesulfonic acid (MPSA)) and 3-N,N-dimethylaminodithiocarbamoyl-1-propane sulfuric acid (3-N,N-dimethlyaminodithiocarbamoyl-1-propanesulfonic acid (DPS)) At least one selected copper plating composition.
6. The method of claim 5,
The copper ion migration inhibitor is at least one selected from the group consisting of polyethylene glycol (PEG), polypropylene glycol (PPG), and copolymers thereof, a copper plating composition.
a) providing a copper plating composition according to any one of claims 1 to 8;
b) a copper plating method comprising the step of immersing a substrate comprising a via hole, a through-hole, a trench or a through electrode in the copper plating composition.
10. The method of claim 9,
The substrate is at least one of a silicon wafer substrate and a PCB substrate, a copper plating method.
A substrate formed by the method of claim 9 .