KR20180014377A - Leveler for plating comprising Choline compounds and copper plating method using the same - Google Patents

Abstract

The present invention relates to a leveler for plating, a copper plating solution and a copper plating method which comprises a choline group at both terminals represented by chemical formulas (1) to (5). It is possible to realize reliable plating.

Description

[0001] The present invention relates to a plating agent for plating comprising a choline compound and a copper plating method using the same,

The present invention relates to a plating agent for plating and a copper plating method using a choline compound.

As electronic devices have become smaller and thinner, aluminum has been replaced by aluminum, which has a relatively low electrical resistance as compared to aluminum, has a high resistance to void generation due to electromigration, Is used as a wiring material.

Copper electroplating is used to form metal interconnects in most electronic devices such as semiconductor substrates, PCBs, microprocessors, and memories. Especially, the most basic purpose of electrolytic plating in semiconductor or PCB process is to fill various patterns formed on the substrate without defects. For this purpose, the role of organic additive contained in the electrolyte is very important. The organic additive is a small amount of organic compound contained in the plating solution, and their composition and concentration are important factors determining the characteristics of the electrodeposited thin film. These materials are classified into a suppressor and an accelerator according to their electrochemical characteristics and a brightener, a carrier, and a leveler according to the influence on the properties of the thin film.

On the other hand, as the flat zeolite, a substance having a functional group having a hetero atom such as nitrogen, oxygen or sulfur is disclosed as an organic compound or a polymer having a large molecular weight.

The prior art of the present invention is the registered patent 10-0885369 which discloses a copper electrolytic plating solution containing a quaternary ammonium bromide flatting agent for level planarization.

An object of the present invention is to provide a plating flatting agent comprising a choline group at both terminals represented by the general formulas (1) to (5).

Another object of the present invention is to provide a copper plating solution containing the above-mentioned flatting agent.

It is another object of the present invention to provide a copper plating method capable of realizing bottom-up type plating by using the flatting agent and preventing seam or void defects.

Other objects and advantages of the present invention will become more apparent from the following detailed description of the invention, claims and drawings.

The present invention relates to a flattening agent in the organic additive of a copper plating solution for defect-free filling of holes in vias or trenches such as semiconductors and PCB substrates. The plating flatting agent of the present invention is a compound having a choline structure at both terminals and has four kinds of derivatives different in the center chain, more specifically, the presence or absence of ethylene glycol (-OCH ₂ CH ₂ O-) It is possible to realize plating in the form of bottom chirping by introducing one of the compounds composed of derivatives having different numbers of glycols (-OCH ₂ CH ₂ O-).

According to an aspect of the present invention, there is provided a plating flat material represented by Chemical Formula (1).

[Chemical Formula 1]

(Wherein E may be C, NH, O or S, n can be from 1 to 10, and X ^- is a counter ion of ammonium)

In one embodiment of the invention, wherein the X ^- is iodide ion (I ^-), bromide ion (Br ^-), chloride ion (Cl ^-), fluoride ion (F ^-), iodate ion (IO ₃ ^-) , hypochlorite ions (ClO ₃ ^-), perchlorate ion (ClO ₄ ^-), bromate ion (BrO ₃ ^-), nitrate ion (NO ₃ ^-), nitrite ion (NO ₂ ^-), hexamethylene hydrofluoric acid ion (PF ₆ ^- , a tetrafluoroborate ion (BF ₄ ^- ), a sulfate ion (HSO ₄ ^- ), and a methyl sulfate ion (CH ₃ SO ₄ ^- ).

According to an embodiment of the present invention, the flattening agent is at least one selected from the following formulas (2) to (5).

(2)

(3)

[Chemical Formula 4]

[Chemical Formula 5]

According to another aspect of the present invention, there is provided a copper plating solution comprising the flatting agent.

According to an embodiment of the present invention, the copper plating solution having the concentration of the flatting agent is 0.1 to 1000 μM.

According to an embodiment of the present invention, the copper plating solution further comprises at least one selected from deionized water, a copper ion compound, a supporting electrolyte chloride ion, an accelerator and an inhibitor.

According to an embodiment of the present invention, the copper ion compound has a concentration of 0.1 to 1.5 M, and the copper ion compound is copper sulfate (CuSO ₄ ), copper methanesulfonate (Cu (CH ₃ SO ₃ ) ₂ ) (CuCO ₃ ), copper cyanide (CuCN), cupric chloride (CuCl ₂ ) and copper perchlorate (Cu (ClO ₄ ) ₂ ).

According to an embodiment of the present invention, the supporting electrolyte has a concentration of 0.1 to 1.2 M, and the supporting electrolyte is selected from the group consisting of sulfuric acid (H ₂ SO ₄ ), methanesulfonic acid (CH ₃ SO ₃ H), sodium sulfate (Na ₂ SO ₄ ) , Potassium sulfate (K ₂ SO ₄ ), boric acid (H ₃ BO ₄ ), and perchloric acid (HClO ₄ ).

According to an embodiment of the present invention, the chlorine ion has a concentration of 0.1 to 3 mM, and the chlorine ion is at least one selected from hydrochloric acid (HCl), sodium chloride (NaCl) and potassium chloride (KCl) .

According to an embodiment of the present invention, the accelerator has a concentration of 1 to 200 μM, the accelerator is bis (3-sulfopropyl) disulfide disodium salt (SPS), 3- 3-mercaptopropanesulfonic acid (MPSA), and 3- N, N -dimethylaminodithiocarbamoyl-1-propanesulfonate (3- N, dimethylamino dithio carbamoyl-1-propanesulfonate; DPS). ≪ / RTI >

According to one embodiment of the present invention, the inhibitor has a molecular weight of 700 to 10000 Da (dalton), and the inhibitor is selected from the group consisting of polyethylene glycol (PEG), polypropylene glycol (PPG), polyoxyethylene glycol a polyoxyethylene glycol, a polyethylene imine, and a copolymer thereof.

According to another aspect of the present invention, there is provided a copper plating method for plating with the copper plating solution described above.

According to an embodiment of the present invention, there is provided a method of manufacturing a semiconductor device, comprising the steps of: pre-treating a substrate on which a via hole is formed; And plating the pre-treated substrate with the copper plating solution described above to form a via.

According to an embodiment of the present invention, the substrate is a silicon substrate, and the via is a through silicon via (TSV).

According to an embodiment of the present invention, a copper plating method is provided in which the via hole has a depth of less than 100 mu m and a diameter of 10 mu m or less.

According to an embodiment of the present invention, the vias are vias having a aspect ratio of 1: 1 or more.

According to an embodiment of the present invention, the pretreatment step is performed by immersing in a solution selected from methanol, ethanol and isopropyl alcohol for 5 to 300 seconds. A plating method is provided.

According to one embodiment of the present invention, forming the vias, 5 it is one to 30 mA / cm ² for less than 500 seconds, and subsequently provided with a copper plating method of applying a 30 to 70 mA / cm ² do.

According to an embodiment of the present invention, the step of forming the vias may include a step of applying a constant current of 5 to 30 mA / cm < 2 > for 1000 seconds or less, stirring the working electrode at 800 to 2000 rpm, Thereby promoting diffusion of the copper plating solution.

According to one embodiment of the present invention, a cholinic compound at both ends can be plated in a bottom chirping shape using a flatting agent.

According to an embodiment of the present invention, it is possible to realize a reliable plating without a defect such as seam or void when a via hole or a trench of a silicon wafer and a PCB substrate is plated have.

Further, according to one embodiment of the present invention, the introduction of ethylene glycol (-OCH ₂ CH ₂ O-) into the central chain of the choline compound and the increase of the number thereof increase the binding of oxygen in the central chain, It is possible to provide a flatting agent and a copper plating solution which facilitate the adsorption of copper (Cu).

Further, according to one embodiment of the present invention, a copper plating method for reducing plating time using a choline compound and a step plating method can be provided.

1 is a cross-sectional view of a silicon through vias (TSV) electroplated using a copper plating solution according to Example 1 of the present invention.
2 is a cross-sectional view of an electroplated silicon through via (TSV) using a copper plating solution according to Example 2 of the present invention.
3 is a cross-sectional view of a silicon through vias (TSV) electroplated using a copper plating solution according to Example 3 of the present invention.
4 is a cross-sectional view of a silicon through vias (TSV) electroplated using a copper plating solution according to Example 4 of the present invention.
5 is a cross-sectional view of a silicon through vias (TSV) electroplated using a copper plating solution according to Comparative Example 5 of the present invention.
6 is a cross-sectional view of electroplated silicon through vias (TSV) of Examples 1 to 4 and Comparative Example 1 of the present invention.
FIG. 7 shows the results of analysis of Examples 1 and 4 of the present invention and the previously reported TEG-based leveling agent by Linear Sweep Voltammetry (LSV).
FIG. 8 shows the results of analysis of Examples 1 to 3 of the present invention and the previously reported TEG-based leveling agent by Linear Sweep Voltammetry (LSV).

Certain terms are hereby defined for convenience in order to facilitate a better understanding of the present invention. Unless otherwise defined herein, scientific and technical terms used in the present invention shall have the meanings commonly understood by one of ordinary skill in the art. Also, unless the context clearly indicates otherwise, the singular form of the term also includes plural forms thereof, and plural forms of the term should be understood as including its singular form.

According to an aspect of the present invention, there is provided a plating flat material represented by Chemical Formula (1). The compounds represented by the above formula (1) may be used alone or in a mixture of two or more kinds.

[Chemical Formula 1]

(Wherein E may be C, NH, O or S, n can be from 1 to 10, and X ^- is a counter ion of ammonium)

In one embodiment of the invention, wherein the X ^- is iodide ion (I ^-), bromide ion (Br ^-), chloride ion (Cl ^-), fluoride ion (F ^-), iodate ion (IO ₃ ^-) , hypochlorite ions (ClO ₃ ^-), perchlorate ion (ClO ₄ ^-), bromate ion (BrO ₃ ^-), nitrate ion (NO ₃ ^-), nitrite ion (NO ₂ ^-), hexamethylene hydrofluoric acid ion (PF ₆ ^- , a tetrafluoroborate ion (BF ₄ ^- ), a sulfate ion (HSO ₄ ^- ), and a methyl sulfate ion (CH ₃ SO ₄ ^- ).

According to an embodiment of the present invention, the flattening agent is at least one selected from the following formulas (2) to (5).

(2)

(3)

[Chemical Formula 4]

[Chemical Formula 5]

According to another aspect of the present invention, there is provided a copper plating solution comprising the flatting agent. The copper plating solution containing the choline compound as a flattening agent may be an aqueous solution or a dispersion.

According to an embodiment of the present invention, the copper plating solution having the concentration of the flatting agent is 0.1 to 1000 μM. The concentration of the flatting agent is preferably 1 to 500 μM, but is not limited thereto.

According to an embodiment of the present invention, the copper plating solution further comprises at least one selected from deionized water, a copper ion compound, a supporting electrolyte chloride ion, an accelerator and an inhibitor. The basic electrolyte of the copper plating solution may be deionized water, a copper ion compound, a supporting electrolyte, and an electrolyte including chlorine ions, but is not limited thereto.

According to an embodiment of the present invention, the copper ion compound has a concentration of 0.1 to 1.5 M, and the copper ion compound is copper sulfate (CuSO ₄ ), copper methanesulfonate (Cu (CH ₃ SO ₃ ) ₂ ) (CuCO ₃ ), copper cyanide (CuCN), cupric chloride (CuCl ₂ ) and copper perchlorate (Cu (ClO ₄ ) ₂ ). The copper ion compound is a source of copper ions, and the concentration of copper ions for smoothly supplying copper ions is preferably 0.2 to 1.3 M, but is not limited thereto.

According to an embodiment of the present invention, the supporting electrolyte has a concentration of 0.1 to 1.2 M, and the supporting electrolyte is selected from the group consisting of sulfuric acid (H ₂ SO ₄ ), methanesulfonic acid (CH ₃ SO ₃ H), sodium sulfate (Na ₂ SO ₄ ) , Potassium sulfate (K ₂ SO ₄ ), boric acid (H ₃ BO ₄ ), and perchloric acid (HClO ₄ ). In the case of the supporting electrolyte, the concentration of the supporting electrolyte for increasing the electrolysis of the copper plating solution is preferably 0.2 to 1.0 M, but is not limited thereto.

According to an embodiment of the present invention, the chlorine ion has a concentration of 0.1 to 3 mM, and the chlorine ion is at least one selected from hydrochloric acid (HCl), sodium chloride (NaCl) and potassium chloride (KCl) . The chlorine ion may be included to assist adsorption of the additive, and the concentration of the chlorine ion is preferably 0.2 to 2 mM, but is not limited thereto.

According to an embodiment of the present invention, the accelerator has a concentration of 1 to 200 μM, the accelerator is bis (3-sulfopropyl) disulfide disodium salt (SPS), 3- 3-mercaptopropanesulfonic acid (MPSA), and 3- N, N -dimethylaminodithiocarbamoyl-1-propanesulfonate (3- N, dimethylamino dithio carbamoyl-1-propanesulfonate; DPS). ≪ / RTI > The accelerator accelerates the rate at which copper is reduced to increase the rate of filling the copper wiring of the semiconductor substrate and the PCB substrate. The accelerator concentration is preferably 1 to 100 μM, but is not limited thereto.

According to one embodiment of the present invention, the inhibitor has a molecular weight of 700 to 10000 Da (dalton), and the inhibitor is selected from the group consisting of polyethylene glycol (PEG), polypropylene glycol (PPG), polyoxyethylene glycol a polyoxyethylene glycol, a polyethylene imine, and a copolymer thereof. The inhibitor reduces the rate at which copper is plated onto the semiconductor substrate and the PCB substrate by reducing the rate of reduction of copper ions. The concentration of the inhibitor may range from 1 to 2000 μM, preferably from 10 to 1500 μM, no.

According to another aspect of the present invention, there is provided a copper plating method for plating with the copper plating solution described above.

According to an embodiment of the present invention, there is provided a method of manufacturing a semiconductor device, comprising the steps of: pre-treating a substrate on which a via hole is formed; And plating the pre-treated substrate with the copper plating solution described above to form a via. The copper plating method may include dipping the pretreated substrate into the copper plating solution of the present invention, and then applying electricity to the substrate to fill the via.

According to an embodiment of the present invention, the substrate is a silicon substrate, and the via is a through silicon via (TSV). And a method of implementing a bottom-up type plating in a via hole or a trench using a choline-based compound as a defect-free plating flattening agent.

According to an embodiment of the present invention, a copper plating method is provided in which the via hole has a depth of less than 100 mu m and a diameter of 10 mu m or less.

According to an embodiment of the present invention, the vias are vias having a aspect ratio of 1: 1 or more.

According to an embodiment of the present invention, the pretreatment step is performed by immersing in a solution selected from methanol, ethanol and isopropyl alcohol for 5 to 300 seconds. A plating method is provided. The preprocessing step of the substrate on which the vias are formed may be performed to improve wettability.

According to one embodiment of the present invention, forming the vias, 5 applied to over 30 mA / cm ² the time of not more than 500 seconds, by applying a 30 to 70 mA / cm ² after the copper to complete the filling A plating method is provided. According to the step plating method as described above, the plating time is saved more than when only the same current is used.

According to an embodiment of the present invention, the step of forming the vias may include a step of applying a constant current of 5 to 30 mA / cm < 2 > for 1000 seconds or less, stirring the working electrode at 800 to 2000 rpm, Thereby promoting diffusion of the copper plating solution.

In the following Examples, plating conditions were as follows. A silicon wafer having a trench having a depth of 40 占 퐉 and a diameter of 9 占 퐉 was pre-treated, immersed in the copper plating solution, and then plated by applying a constant current of 15 mA / cm2 for 750 seconds. During plating, the temperature of the plating solution was maintained at 25 ° C. The working electrode on which the silicon wafer was placed was stirred at 1000 rpm to promote the diffusion of copper ions into the trench. The flattening agent was adsorbed at the entrance of the trench, Copper electrodeposition was suppressed. The composition of the plating liquid used for carrying out the embodiment is specified in the following examples.

Hereinafter, the present invention will be described in more detail with reference to Examples. It should be understood, however, that these examples are for illustrative purposes only and are not to be construed as limiting the scope of the present invention.

Preparation of copper plating solution

Example  One.

The following materials were stirred and dissolved by using deionized water as a solvent, and the composition of the plating solution was as follows.

Copper ion source: 1.0 M copper sulfate (CuSO ₄ .5H ₂ O)

Supporting electrolyte: 0.5 M sulfuric acid (H ₂ SO ₄ )

Chlorine ion source: 1.37 mM NaCl

Inhibitor: 50 μM PEG-PPG-PEG (molecular weight 1,100; poly (ethylene glycol) -block-poly (propylene glycol)

 Accelerator: 10 [mu] M SPS (bis- (sodium sulfopropyl) -disulfide)

 Platelet agent: 50 μM of a compound represented by the following formula 2

(2)

Example  2.

A plating solution having the same composition as in Example 1 was used, except that the compound represented by Formula 3 was used as a flatting agent.

(3)

Example  3.

A plating solution having the same composition as in Example 1 was used, except that the compound represented by Chemical Formula 4 was used as a flatting agent.

[Chemical Formula 4]

Example  4.

A plating solution having the same composition as in Example 1 was used, except that the compound represented by Chemical Formula 5 was used as a flatting agent.

[Chemical Formula 5]

Comparative Example  One

A plating solution having the same composition as in Example 1 was used, except that a flatting agent was not added.

result

Silicone penetration Via (TSV)  Analyzing Filling Results

In order to confirm the performance of the choline-based compound used as the flatting agent according to the present invention, the results depending on the application of the choline-based compound were compared (see FIG. 6).

In the plating solution containing no choline-series flattening agent (Comparative Example 1), plating defects were found under the same plating conditions, but Examples 1 to 4 including the plating agent in the choline series of the formulas 2 to 5 showed defect- And it was confirmed that the plating proceeded. It was also confirmed that the defect-free plating proceeded also in the structure (Example 2 or 5) in which the intermediate chain length was changed and in the structure in which the number of oxygen included was changed (Example 2 or 4).

From the above results, it can be seen that, by using the choline type flatting agent according to the present invention and the copper plating solution containing the same, it is possible to realize bottom-up type plating and copper plating without defects such as seams and voids , And it was confirmed through the structural modification of the additional flatting agent that if the length of the central chain of the flatting agent is increased, the binding of oxygen in the central chain is increased to facilitate adsorption of the inhibitor or copper (Cu) .

FIGS. 7 and 8 show a copper ion source: 1.0 M copper sulfate (CuSO ₄ .5H ₂ O); Supporting electrolyte: 0.5 M of sulfuric acid (H ₂ SO _4); Chlorine ion source: 1.37 mM NaCl; Flattening agent: 50 mu M of the compound represented by formulas (2) to (5); The results were analyzed by linear sweep voltammetry (LSV) under stirring conditions of 1000 rpm. The results are compared with the previously reported TEG-based levelers ( ECS Electrochemistry Letters , 2015 , 4 (10), D31-D34).

According to the results of the LSV analysis of Examples 1 and 4 and the conventional leveling agent, as the length of the central chain increases, that is, as the number of ethylene glycol (-OCH ₂ CH ₂ O-) increases, , And the inhibitory effect was significantly higher than the TEG-based leveler reported in the prior art (see FIG. 7).

Further, according to the results of the LSV analysis of Examples 1 to 3 and the conventional leveling agent, even when ethylene glycol (-OCH ₂ CH ₂ O-) was absent in the center chain, the inhibitory effect was exhibited (see FIG. 8).

The terms used in the present invention are intended to illustrate specific embodiments and are not intended to limit the invention. The word "comprises" or "having" means that there is a feature, a number, a step, an operation, an element, or a combination thereof described in the specification. The present invention is not limited to the above-described embodiments and the accompanying drawings, but is intended to be limited only by the appended claims. It will be apparent to those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. something to do.

Claims (19)

1. A plating flatting agent represented by the following formula (1).
[Chemical Formula 1]

(Wherein E may be C, NH, O or S, n can be from 1 to 10, and X ^- is a counter ion of ammonium)
The method according to claim 1,
Wherein X ^- is iodide ion (I ^-), bromide ion (Br ^-), chloride ion (Cl ^-), fluoride ion (F ^-), iodate ion (IO ₃ ^-), chlorate ion (ClO ₃ ^-), perchloric acid ion (ClO ₄ ^-), bromate ion (BrO ₃ ^-), nitrate ion (NO ₃ ^-), nitrite ion (NO ₂ ^-), hexamethylene hydrofluoric acid ion (PF ₆ ^-), tetrafluoride borate ion (BF ₄ ^- ), sulfate ion (HSO ₄ ^- ), and methyl sulfate ion (CH ₃ SO ₄ ^- ).
The method according to claim 1,
Wherein the flatting agent is at least one selected from the following formulas (2) to (5).
(2)

(3)

[Chemical Formula 4]

[Chemical Formula 5]

A copper plating solution comprising the flatting agent according to any one of claims 1 to 3.
5. The method of claim 4,
And the concentration of the flatting agent is 0.1 to 1000 占 퐉.
5. The method of claim 4,
Wherein the copper plating solution further comprises at least one selected from deionized water, a copper ion compound, a supporting electrolytic chloride ion, an accelerator and an inhibitor.
The method according to claim 6,
The copper ion compound has a concentration of 0.1 to 1.5 M,
The copper ion compound is copper sulfate (CuSO _4), copper methanesulfonate _{(Cu (CH 3 SO 3)} 2), copper carbonate (CuCO _3), cyan East (CuCN), cupric chloride (CuCl ₂₎ and perchloric acid copper (Cu (ClO _{4) 2)} copper plating solution is at least one selected from the.
The method according to claim 6,
The supporting electrolyte has a concentration of 0.1 to 1.2 M,
The supporting electrolyte may be selected from the group consisting of sulfuric acid (H ₂ SO ₄ ), methanesulfonic acid (CH ₃ SO ₃ H), sodium sulfate (Na ₂ SO ₄ ), potassium sulfate (K ₂ SO ₄ ), boric acid (H ₃ BO ₄ ) ₄ ) at least one copper plating solution.
The method according to claim 6,
The chloride ion has a concentration of 0.1 to 3 mM,
Wherein the chlorine ion is at least one selected from hydrochloric acid (HCl), sodium chloride (NaCl), and potassium chloride (KCl).
The method according to claim 6,
Wherein the accelerator has a concentration of 1 to 200 [mu] M,
The accelerator is bis (3-sulfopropyl) disulfide (bis (3-sulfopropyl) disulfide disodium salt; SPS), 3-mercapto propane sulfonic acid (3-mercaptopropanesulfonic acid; MPSA) , and 3-N, N - dimethyl (3- N , N- dimethylaminodithiocarbamoyl-1-propanesulfonate (DPS)).
The method according to claim 6,
Wherein the inhibitor has a molecular weight of 700 to 10,000 Da (dalton)
Wherein the inhibitor is at least one selected from the group consisting of polyethylene glycol (PEG), polypropylene glycol (PPG), polyoxyethylene glycol, polyethylene imine and copolymers thereof.
A copper plating method for plating with the copper plating solution according to claim 4.
13. The method of claim 12,
Pretreating the substrate on which the via hole is formed; And
And plating the pre-treated substrate with the copper plating solution according to claim 4 to form a via.
14. The method of claim 13,
Wherein the substrate is a silicon substrate and the via is a through silicon via (TSV).
14. The method of claim 13,
Wherein the via hole has a depth of less than 100 mu m and a diameter of 10 mu m or less.
14. The method of claim 13,
Wherein the vias have an aspect ratio of at least 1: 1.
14. The method of claim 13,
Wherein the pretreatment step is carried out in a solution selected from methanol, ethanol and isopropyl alcohol for 5 to 300 seconds.
14. The method of claim 13,
Wherein the forming of the vias is performed by applying 5 to 30 mA / cm < ² > for a time of 500 seconds or less, and then applying 30 to 70 mA / cm < ² >.
14. The method of claim 13,
Wherein the forming of the vias is performed by applying a constant current of 5 to 30 mA / cm < 2 > for 1000 seconds or less, and stirring the working electrode at 800 to 2000 rpm to promote diffusion of copper ions into the via.

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