Additive for defect-free filling of through-silicon via and copper electroplating method using same

Abstract

One embodiment of the present specification provides an additive for defect-free filling of a through-silicon via, the additive comprising a tris-ammonium compound represented by chemical formula 1: [chemical formula 1] In chemical formula 1, R1 to R6 are each independently hydrogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or a substituted or unsubstituted alkynyl group; L1 to L3 are each independently a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkenylene group, a substituted or unsubstituted alkynylene group, or a substituted or unsubstituted heteroalkylene group; A1 to A3 are each independently hydrogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted aliphatic hydrocarbon ring, a substituted or unsubstituted aromatic hydrocarbon ring, a substituted or unsubstituted aliphatic heterocyclic ring, or a substituted or unsubstituted aromatic heterocyclic ring; and X- is a counterion of ammonium.

Description

Defect-free filling additive for silicon through-vias and copper electroplating method using the same

[0001] The present specification relates to an additive for defect-free filling of silicon through-vias, a copper electroplating solution containing the same, and a copper electroplating method using the same.

[0002] Through Silicon Via (TSV) are metal wirings required for the vertical stacking of silicon-based chips and are formed through the electroplating of copper. Through Silicon Via are high aspect ratio structures with an aspect ratio of 10:1, typically having a diameter of 5 μm and a depth of 50 μm. Since the formation of defects in through Silicon Via leads to increased resistance and reduced reliability, making it difficult to form high-performance semiconductor package devices, the application of defect-free filling technology through electroplating is essential.

[0003] In the conventional copper electroplating process, a three-additive system is applied in which organic accelerators, decelerators, and leveling agents are essentially added to an electrolyte containing copper ions, sulfuric acid, and chloride ions during the electroplating of copper for defect-free filling of silicon through-vias.

[0004] However, when three or more types of organic additives are present in the electrolyte, the concentration of each additive must always be maintained within a processable range, so it is necessary to measure the concentration of each additive. However, since the electrochemical behavior of each additive differs, concentration analysis takes a long time and in-situ analysis is impossible. In addition, because the decomposition rates of each additive differ, there is a problem that the complexity of the electroplating process increases as the number of additive types increases.

[0005] In addition, since each additive decomposes within the acidic electrolyte to form byproducts, the properties of the electrolyte deteriorate, and the excessive accumulation of byproducts can reduce the lifespan of the electrolyte. Furthermore, as the variety of additives increases, a larger amount of byproducts is generated, making it difficult to control the interactions between the generated byproducts. In particular, in the case of polymeric moderators such as PEG or PEG-PPG block copolymers, the long chain structure breaks down into PEG or PPG with small molecular weights. Since PEG and PEG-PPG molecules with small molecular weights also possess adsorption properties, this affects electrochemical analysis. Due to the altered electrochemical behavior, it becomes difficult to accurately measure the concentration of additives and maintain electrolyte properties, and there are problems that cause a deterioration in packing properties.

[0006] In addition, while defect-free filling is possible with a 3-additive system for silicon through-vias with an aspect ratio of 10:1, defect-free filling is difficult at aspect ratios higher than that, and in particular, plating near the entrance of the silicon through-via, that is, on the upper wall surface, is not completely suppressed, so there is a possibility that a void may be trapped inside the silicon through-via.

[0007] Therefore, there is a need to develop a method that can achieve defect-free filling of silicon through-vias while overcoming the limitations of conventional 3-additive systems.

[0008] The details of this specification are intended to solve the problems of the prior art described above, and one objective of this specification is to provide an additive for defect-free filling of silicon through-vias that enables defect-free filling of silicon through-vias using only one type of organic additive.

[0009] Another objective of the present specification is to provide a copper electroplating solution capable of defect-free filling of silicon through-vias and a copper electroplating method using the same.

[0010] According to one aspect, a defect-free filling additive for silicon through-vias is provided, comprising a tris-ammonium compound represented by the following chemical formula 1.

[0011] [Chemical Formula 1]

[0012]

[0013] In the above formula 1, R1 to R6 are each independently hydrogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or a substituted or unsubstituted alkynyl group, L1 to L3 are each independently a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkenylene group, a substituted or unsubstituted alkynylene group, or a substituted or unsubstituted heteroalkylene group, A1 to A3 are each independently hydrogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted aliphatic hydrocarbon ring, a substituted or unsubstituted aromatic hydrocarbon ring, a substituted or unsubstituted aliphatic heterocycle, or a substituted or unsubstituted aromatic heterocycle, and X- is the counterion of ammonium.

[0014] In one embodiment, in Formula 1, R1 to R6 are each independently hydrogen or a substituted or unsubstituted C1 to C6 alkyl group, L1 to L3 are each independently a single bond or a substituted or unsubstituted C1 to C6 alkylene group, and A1 to A3 are each independently C6 to C 30 It is a substituted or unsubstituted aromatic hydrocarbon ring of, and X - It can be the counterion of ammonium.

[0015] In one embodiment, the X - is iodide ion (I - ), bromide ions (Br - ), chloride ions (Cl - ), fluoride ion (F - ), iodate ion (IO3 -), chlorate ion (ClO3 - ), perchlorate ion (ClO4 - ), bromate ion (BrO3 - ), nitrate ions (NO3 - ), nitrite ions (NO2 - ), hexafluoride phosphate ion (PF6 - ), tetrafluoride ion (BF4 - ), sulfate ions (HSO4) - ), methyl sulfate ion (CH3SO4 - It may be one selected from a group consisting of ) and combinations of 2 or more of these.

[0016] In one embodiment, the tris-ammonium compound may be a compound represented by the following chemical formula 2 or the following chemical formula 3.

[0017] [Chemical Formula 2]

[0018]

[0019] [Chemical Formula 3]

[0020]

[0021] According to another aspect, a copper electroplating solution is provided that includes an additive for defect-free filling of the silicon through-via.

[0022] In one embodiment, the concentration of the defect-free filling additive for the silicon through-via may be 5 to 1000 μM.

[0023] In one embodiment, the copper electroplating solution may further include one selected from the group consisting of deionized water, a copper ion compound, a supporting electrolyte, a halogen compound, and a combination of two or more of these.

[0024] In one embodiment, the copper ion compound may be one selected from the group consisting of copper sulfate (CuSO4), copper methanesulfonate (Cu(CH3SO3)2), copper carbonate (CuCO3), copper cyanide (CuCN), copper(II) chloride (CuCl2), copper perchlorate (Cu(ClO4)2), and combinations of two or more of these.

[0025] In one embodiment, the supporting electrolyte may be one selected from the group consisting of sulfuric acid (H2SO4), methanesulfonic acid (CH3SO3H), sodium sulfate (Na2SO4), potassium sulfate (K2SO4), boric acid (H3BO3), perchloric acid (HClO4), and combinations of two or more of these.

[0026] In one embodiment, the halogen compound may be one selected from the group consisting of hydrochloric acid (HCl), sodium chloride (NaCl), potassium chloride (KCl), hydrogen bromide (HBr), sodium bromide (NaBr), potassium bromide (KBr), hydrogen iodide (HI), sodium iodide (NaI), potassium iodide (KI), and combinations of two or more of these.

[0027] According to another aspect, a copper electroplating method is provided, which involves plating with the copper electroplating solution.

[0028] In one embodiment, the copper electroplating method may include: (a) a step of pre-treating a silicon substrate having via holes formed therein; and (b) a step of plating the pre-treated silicon substrate with the copper electroplating solution to form silicon through-vias.

[0029] In one embodiment, the aspect ratio of the via hole may be 2:1 to 50:1.

[0030] In one embodiment, the pretreatment of step (a) may be performed by immersing a silicon substrate having via holes formed therein in a solution selected from the group consisting of methanol, ethanol, isopropyl alcohol, and a combination of two or more of these.

[0031] An additive for defect-free filling of silicon through-vias according to one aspect of the present specification effectively suppresses copper electrodeposition on the upper wall surface of silicon through-vias, so that defect-free filling of silicon through-vias is possible even when using only one type of additive, and the problem of deterioration of filling characteristics caused by the easy maintenance and analysis of the additive concentration and the small amount of by-products can be solved.

[0032] In addition, a copper electroplating solution and a copper electroplating method using the same according to another aspect of the present specification include an additive capable of effectively suppressing copper electrodeposition on the upper wall surface of a silicon through-via, thereby achieving defect-free filling of the silicon through-via.

[0033] The effects of one aspect of this specification are not limited to the effects described above, and should be understood to include all effects that can be inferred from the configurations described in the detailed description or claims of this specification.

[0034] Figure 1 is the result of cyclic voltammetry analysis for the embodiments and comparative examples of the present specification.

[0035] Figure 2 is the result of cyclic voltammetry analysis by concentration for one embodiment of the present specification.

[0036] FIG. 3 is a cross-sectional image of a TSV taken as a result of a TSV filling experiment according to one embodiment of the present specification (Fig. 3(a): additive L2 concentration 50 μM, Fig. 3(b): additive L2 concentration 75 μM, Fig. 3(c): additive L2 concentration 100 μM).

[0037] FIG. 4 is a cross-sectional image of a TSV taken as a result of a TSV filling experiment for a comparative example of the present specification (Fig. 4(a): comparative additive F1 concentration 50 μM, Fig. 4(b): comparative additive F2 concentration 50 μM).

[0038] FIG. 5 is a cross-sectional image of a TSV taken as a result of a TSV filling experiment for one embodiment of the present specification (Fig. 5(a): additive L1 concentration 50 μM).

[0039] Hereinafter, one aspect of the present specification will be described with reference to the attached drawings. However, the details described in the present specification may be implemented in various different forms and are therefore not limited to the embodiments described herein. Furthermore, in order to clearly explain one aspect of the present specification in the drawings, parts unrelated to the explanation have been omitted, and similar parts throughout the specification have been given similar reference numerals.

[0040] Throughout the specification, when a part is described as "including" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but rather allows for the inclusion of additional components.

[0041] When a range of numerical values ​​is described in this specification, unless a specific range is otherwise described, the value has the precision of significant figures provided according to the standard rules in chemistry for significant figures. For example, 10 includes a range of 5.0 to 14.9, and the number 10.0 includes a range of 9.50 to 10.49.

[0042] Unless otherwise defined, the term 'substitution' as used herein means that one or more hydrogen atoms bonded to a carbon atom of a compound are each independently replaced by other substituents. The substituents may be silyl groups, alkoxy groups, amino groups, cyano groups, nitro groups, or halogen groups, but are not limited thereto.

[0043] As used herein, the term “alkyl group” refers to a carbon atom having a valence of 1 and numbering 1 to 60 (C1 to C 60 Aliphatic saturated hydrocarbon group of ) n H 2n+1 - It can mean. For example, methyl group, ethyl group, propyl group, n-propyl group, isopropyl group, butyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group, n-pentyl group, hexyl group, n-hexyl group, heptyl group, n-heptyl group, octyl group, n-octyl group, etc., can be mentioned, but are not limited thereto.

[0044] As used herein, the term “alkenyl group” refers to a carbon atom having 1 valence and containing one or more double bonds, having 2 to 60 carbon atoms (C2 to C 60 It can mean the hydrocarbon group of ).

[0045] As used herein, the term “alkynyl group” refers to a carbon atom having 1 valence and containing one or more triple bonds, having 2 to 60 carbon atoms (C2 to C 60 It can mean the hydrocarbon group of ).

[0046] As used herein, the term “alkylene group” refers to a carbon atom having 2 valence and numbering 1 to 60 (C1 to C 60 Acyclic hydrocarbon group of ) n H 2n It can mean -“. For example, methylene groups (-CH2-), ethylene groups (-CH2-CH2-), propylene groups (-CH2CH2CH2-), etc., but are not limited to these.

[0047] As used herein, the term “alkenylene group” refers to a carbon atom having 2 to 60 carbon atoms (C2 to C6) having a valence of 2 and containing one or more double bonds. 60 It can mean the acyclic hydrocarbon group of ).

[0048] As used herein, the term “alkynylene group” refers to a carbon atom having 2 to 60 carbon atoms (C2 to C6) having 2 valencies and containing one or more triple bonds. 60It can mean the acyclic hydrocarbon group of ).

[0049] As used in this specification, the term “heteroatom” refers to all atoms excluding carbon and hydrogen, such as, but not limited to, oxygen, nitrogen, sulfur, phosphorus, and halogen atoms.

[0050] The term “heteroalkylene group” as used in this specification may mean an alkylene group in which at least one carbon is substituted with a heteroatom.

[0051] As used herein, the term 'aliphatic hydrocarbon ring' refers to a ring with 3 to 60 carbon atoms (C3 to C 60 It can mean a ring composed only of carbon and hydrogen atoms as a non-aromatic ring.

[0052] As used herein, the term 'aromatic hydrocarbon ring' refers to a ring with 6 to 60 carbon atoms (C6 to C 60 It refers to an aromatic ring consisting only of carbon and hydrogen atoms, for example, the benzene (C6H6) ring, naphthalene (C 10 H8) ring, anthracene (C 14 H 10 ) ring, phenanthrene(C 14 H 10 Examples include rings, but are not limited to these.

[0053] As used herein, the term 'aliphatic heterocycle' refers to a ring with 3 to 60 carbon atoms (C3 to C6 60 It can mean a hydrocarbon ring in which at least one carbon is substituted with a heteroatom as a non-aromatic ring.

[0054] As used herein, the term 'aromatic heterocycle' refers to a ring with 6 to 60 carbon atoms (C6 to C6 60 As an aromatic ring, it may mean a hydrocarbon ring in which at least one carbon is substituted with a heteroatom.

[0055] Hereinafter, an embodiment of the present specification will be described in detail with reference to the attached drawings.

[0056] Defect-free filling additive for silicone through-vias

[0057] An additive for defect-free filling of silicon through-vias according to one aspect of the present specification comprises a tris-ammonium compound represented by the following chemical formula 1.

[0058] [Chemical Formula 1]

[0059]

[0060] In the above Chemical Formula 1, R1 to R6 are each independently hydrogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or a substituted or unsubstituted alkynyl group. In one embodiment, R1 to R6 may each independently be hydrogen or a C1-C6 substituted or unsubstituted alkyl group, but are not limited thereto. In another embodiment, R1 to R6 may each independently be a methyl group or an ethyl group, but are not limited thereto.

[0061] In the above Chemical Formula 1, L1 to L3 are each independently a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkenylene group, a substituted or unsubstituted alkynylene group, or a substituted or unsubstituted heteroalkylene group. In one embodiment, L1 to L3 may each independently be a single bond or a C1 to C6 substituted or unsubstituted alkylene group, but are not limited thereto. In another embodiment, L1 to L3 may be a methylene group, but are not limited thereto.

[0062] In the above Chemical Formula 1, A1 to A3 are each independently hydrogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted aliphatic hydrocarbon ring, a substituted or unsubstituted aromatic hydrocarbon ring, a substituted or unsubstituted aliphatic heterocycle, or a substituted or unsubstituted aromatic heterocycle. In one embodiment, A1 to A3 are each independently C6 to C30 It may be a substituted or unsubstituted aromatic hydrocarbon ring, but is not limited thereto. In another embodiment, A1 to A3 may be a naphthalene ring, but is not limited thereto.

[0063] In the above chemical formula 1, X - is the counterion of ammonium.

[0064] The above X - is iodide ion (I - ), bromide ions (Br - ), chloride ions (Cl - ), fluoride ion (F - ), iodate ion (IO3 - ), chlorate ion (ClO3 - ), perchlorate ion (ClO4 - ), bromate ion (BrO3 - ), nitrate ions (NO3 - ), nitrite ions (NO2 - ), hexafluoride phosphate ion (PF6 - ), tetrafluoride ion (BF4 - ), sulfate ions (HSO4) - ), methyl sulfate ion (CH3SO4 - It may be one selected from a group consisting of ) and combinations of 2 or more of these, but is not limited thereto.

[0065] In one embodiment, the X - is chloride ions (Cl - It may be ) and in this case, the tris-ammonium compound represented by the above chemical formula 1 may be a tris-ammonium chloride salt, but is not limited thereto.

[0066] The defect-free filling additive for the above silicon through-via can inhibit copper electrodeposition by adsorbing to the upper wall of the silicon through-via and physically restricting the access of copper ions, and can inhibit copper electrodeposition on the upper wall of the via without detaching until copper is electrodeposited and fills up the lower part of the via. Accordingly, when using the defect-free filling additive for the above silicon through-via, bottom filling of copper is possible, and a high aspect ratio silicon through-via structure can be plated in a short time without internal defects.

[0067] The above-mentioned defect-free filling additive for silicon through-vias effectively suppresses copper electrodeposition on the upper wall surface of silicon through-vias, so that, unlike the conventional three-additive system which necessarily requires the addition of an accelerator, a decelerator, and a leveling agent, copper bottom filling is possible even when using only one type of additive, and accordingly, defect-free filling of silicon through-vias can be achieved.

[0068] The tris-ammonium compound included in the defect-free filling additive for the above silicon through-via has a smaller molecular weight compared to the high molecular weight moderator used in the conventional 3-additive system and does not have a long chain structure, so it can solve the problem of byproduct generation due to additive decomposition and the resulting degradation of filling characteristics.

[0069] The above tris-ammonium compound may be a compound represented by the following chemical formula 2 or the following chemical formula 3, but is not limited thereto.

[0070] [Chemical Formula 2]

[0071]

[0072] [Chemical Formula 3]

[0073]

[0074] copper electroplating solution

[0075] A copper electroplating solution according to another aspect of the present specification comprises an additive for defect-free filling of the aforementioned silicon through-vias.

[0076] The copper electroplating solution described above contains an additive that can effectively suppress copper electrodeposition on the upper wall surface of the silicon through-via, thereby enabling bottom filling of copper and, accordingly, defect-free filling of the silicon through-via can be achieved.

[0077] The concentration of the defect-free filling additive for the above silicon through-via can be 5 to 1000 μM. For example, 5 μM, 10 μM, 15 μM, 20 μM, 25 μM, 30 μM, 35 μM, 40 μM, 45 μM, 50 μM, 55 μM, 60 μM, 65 μM, 70 μM, 75 μM, 80 μM, 85 μM, 90 μM, 95 μM, 100 μM, 105 μM, 110 μM, 115 μM, 120 μM, 125 μM, 130 μM, 135 μM, 140 μM, 145 μM, 150 μM, 155 μM, 160 μM, 165 μM, 170 μM, 175 μM, 180 μM μM, 185 μM, 190 The concentration of the additive for defect-free filling of the silicon through-via contained in the copper electroplating solution may be less than the above range, and the effect of inhibiting copper electrodeposition on the upper wall surface of the silicon through-via due to the use of the additive may be reduced, and if it exceeds the above range, selective copper electrodeposition on the bottom surface of the silicon through-via may become impossible.

[0078] The copper electroplating solution may further include one selected from the group consisting of deionized water, a copper ion compound, a supporting electrolyte, a halogen compound, and a combination of two or more of these. In one embodiment, the copper electroplating solution may further include an electrolyte comprising deionized water, a copper ion compound, a supporting electrolyte, and a halogen compound.

[0079] The copper electroplating solution described above may not include accelerators, decelerators, and leveling agents, which are additives included in conventional copper electroplating solutions. By using only one type of additive, the copper electroplating solution facilitates the maintenance and analysis of additive concentrations and produces fewer byproducts, thereby resolving issues regarding interactions between byproducts and the resulting degradation of filling characteristics. Furthermore, it offers higher efficiency compared to conventional technology and reduces process complexity.

[0080] The copper ion compound may be selected from the group consisting of copper sulfate (CuSO4), copper methanesulfonate (Cu(CH3SO3)2), copper carbonate (CuCO3), copper cyanide (CuCN), copper(II) chloride (CuCl2), copper perchlorate (Cu(ClO4)2), and combinations of two or more of these, but is not limited thereto.

[0081] The concentration of the copper ion compound may be 0.1 to 1.5 M. For example, it may be 0.1 M, 0.2 M, 0.3 M, 0.4 M, 0.5 M, 0.6 M, 0.7 M, 0.8 M, 0.9 M, 1.0 M, 1.1 M, 1.2 M, 1.3 M, 1.4 M, 1.5 M, or a range between two of these values. If the concentration of the copper ion compound is below the above range, the concentration of copper is too low to obtain a sufficient copper filling effect, and if it exceeds the above range, the copper ion compound may not completely dissolve at room temperature.

[0082] The above supporting electrolyte may be one selected from the group consisting of sulfuric acid (H2SO4), methanesulfonic acid (CH3SO3H), sodium sulfate (Na2SO4), potassium sulfate (K2SO4), boric acid (H3BO3), perchloric acid (HClO4), and combinations of two or more of these, but is not limited thereto.

[0083] The concentration of the above-mentioned supporting electrolyte may be 0.1 to 1.2 M. For example, it may be 0.1 M, 0.2 M, 0.3 M, 0.4 M, 0.5 M, 0.6 M, 0.7 M, 0.8 M, 0.9 M, 1.0 M, 1.1 M, 1.2 M, or a range between two of these values.

[0084] The above halogen compound may be one selected from the group consisting of hydrochloric acid (HCl), sodium chloride (NaCl), potassium chloride (KCl), hydrogen bromide (HBr), sodium bromide (NaBr), potassium bromide (KBr), hydrogen iodide (HI), sodium iodide (NaI), potassium iodide (KI), and combinations of two or more of these, but is not limited thereto.

[0085] The concentration of the halogen compound may be 0.1 to 5 mM. For example, it may be 0.1 mM, 0.5 mM, 1 mM, 1.5 mM, 2 mM, 2.5 mM, 3 mM, 3.5 mM, 4 mM, 4.5 mM, 5 mM, or a range between two of these values. The halogen compound is added to help adsorb the additive, and if the concentration of the halogen compound is below the above range, the amount of adsorption of the additive may not be sufficient, and if it exceeds the above range, a copper-halogen precipitate may form, which may interfere with electroplating.

[0086] Copper electroplating method

[0087] A copper electroplating method according to another aspect of the present specification comprises the step of plating with the copper electroplating solution described above.

[0088] The above copper electroplating method uses an additive that can effectively suppress copper electrodeposition on the upper wall surface of a silicon through-via, thereby enabling bottom filling of copper and, accordingly, defect-free filling of the silicon through-via can be achieved.

[0089] The copper electroplating method described above may include: (a) a step of pre-treating a silicon substrate having via holes formed therein; and (b) a step of plating the pre-treated silicon substrate with the copper electroplating solution to form silicon through-vias.

[0090] The aspect ratio of the above via hole may be 2:1 to 50:1. For example, it may be 2:1, 5:1, 10:1, 15:1, 20:1, 25:1, 30:1, 35:1, 40:1, 45:1, 50:1, or a range between two of these ratios. The copper electroplating method described above uses a copper electroplating solution containing the aforementioned additive for defect-free filling of silicon through-vias, thereby effectively suppressing copper electrodeposition on the upper wall surface of the silicon through-via, and enabling defect-free filling of silicon through-vias having a high aspect ratio.

[0091] The diameter of the above via hole may be 2 to 150 μm. For example, it may be 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, or a range between two of these values.

[0092] The depth of the via hole may be 10 to 350 μm. For example, it may be 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, or a range between two of these values.

[0093] A diffusion barrier and a seed layer may be formed on the surface of the silicon substrate having the above via holes formed therein through physical vapor deposition, chemical vapor deposition, and electroless plating. The diffusion barrier may be formed from one selected from the group consisting of tantalum, tantalum nitride, titanium, titanium nitride, and combinations of two or more of these, and the seed layer may be formed from one selected from the group consisting of copper, silver, nickel, ruthenium, cobalt, iridium, and combinations of two or more of these.

[0094] The pretreatment of step (a) above can be performed by immersing a silicon substrate having via holes formed therein in a solution selected from the group consisting of methanol, ethanol, isopropyl alcohol, and combinations of two or more of these. Through the pretreatment of step (a), the wettability inside the via holes can be improved.

[0095] The plating in step (b) above can be performed by immersing the pretreated silicon substrate in the copper electroplating solution and then applying current to the substrate. In one embodiment, the plating in step (b) above can be performed by immersing the pretreated silicon substrate in the copper electroplating solution and then applying current to the substrate while rotating it.

[0096] The embodiments of this specification will be described in more detail below. However, the following experimental results represent only representative results among the above embodiments, and the scope and content of this specification should not be interpreted as being narrowed or limited by the embodiments. The respective effects of various embodiments of this specification not explicitly presented below will be described in detail in the relevant sections.

[0097] Example 1

[0098] Triglycidyl isocyanurate (2 mmol, 756 mg) and a 2 M dimethylamine solution dissolved in methanol (12 mmol, 6.0 equivalents) were added to a 25 mL round-bottom flask at room temperature and stirred overnight. After the starting materials were completely consumed, the reaction mixture was concentrated under reduced pressure. The resulting residue was then dissolved in THF (2 mL), and 1-chloromethyl naphthalene (7.2 mmol, 3.6 equivalents) was added. The reaction mixture was stirred overnight at room temperature and then concentrated under reduced pressure to obtain a viscous oil-form additive L1 in a quantitative yield (2.108 g). HRMS (FAB) calcd for C 51 H 63 35 Cl2N6O6[M-Cl] + : 925.4181; found: 925.4188.

[0099] The synthesis process of the above additive L1 is briefly summarized in Reaction Scheme 1 below.

[0100] [Reaction Equation 1]

[0101]

[0102] Example 2

[0103] Additive L2 in the form of a viscous oil was obtained in a quantitative yield (2.108 g) in the same manner as in Example 1, except that the 2 M dimethylamine solution (12 mmol, 6.0 equivalents) dissolved in methanol was replaced with diethylamine (1.25 mL) dissolved in methanol (6 mL). HRMS (FAB) calcd for C 57 H 75 35 Cl2N6O6[M-Cl] + : 1009.5120; found: 1009.5115.

[0104] The synthesis process of the above additive L2 is briefly summarized in Reaction Scheme 2 below.

[0105] [Reaction Equation 2]

[0106]

[0107] Comparative Example 1

[0108] A compound represented by the following chemical formula A was used as comparative additive F1.

[0109] [Chemical Formula A]

[0110]

[0111] Comparative Example 2

[0112] A compound represented by the following chemical formula B was used as comparative additive F2.

[0113] [Chemical Formula B]

[0114]

[0115] Experimental Example 1

[0116] To compare the copper electrodeposition inhibitory effects of additive L2 prepared in Example 2 above and comparative additives F1 and F2 of Comparative Examples 1 and 2 above, cyclic voltammetry (CV) analysis was performed. The results are shown in Figure 1.

[0117] Referring to Figure 1, it was confirmed that the copper electrodeposition inhibitory effect of comparative additives F1 and F2 is similar to the case without additives (w / o), whereas additive L2 exhibits a copper electrodeposition inhibitory effect.

[0118] Experimental Example 2

[0119] To compare the degree of copper electrodeposition inhibition according to the concentration of additive L2 prepared in Example 2 above, cyclic voltammetry (CV) analysis was performed while adjusting the concentration of additive L2 from 0 to 150 μM. The results are shown in Figure 2.

[0120] Referring to Figure 2, it was confirmed that as the concentration of additive L2 increased from 0 μM to 125 μM, the overpotential required to generate a reduction current of copper ions increased, thereby improving the degree of copper electrodeposition inhibition. However, it was confirmed that at concentrations above 125 μM, the additive became saturated in the electrolyte, and the degree of copper electrodeposition inhibition did not increase. Through this, it was confirmed through the electrochemical behavior of the additive that copper electrodeposition is inhibited as the concentration of the additive increases up to a certain level.

[0121] Experimental Example 3

[0122] In order to determine whether defect-free filling of through silicon vias (TSVs) can be achieved when additive L2 prepared in Example 2 and comparative additives F1 and F2 of Comparative Examples 1 and 2 are used as additives, a TSV filling experiment was performed in the following manner.

[0123] (1) TSV wafer preparation

[0124] A silicon wafer (Si wafer) was etched to form a via hole structure with a diameter of 5 μm and a depth of 50 μm (aspect ratio 10:1). A Ti diffusion barrier layer was deposited to a thickness of 100 nm inside the via hole, and a Cu seed layer was deposited to a thickness of 1.5 μm on top of it.

[0125] (2) Electrolyte preparation

[0126] 300 ml of an electrolyte of 1 M CuSO4 + 0.5 M H2SO4 was prepared by placing it in a 400 ml capacity beaker. To the prepared electrolyte, a stock solution of NaCl was added to achieve a concentration of 1 mM, and additive L2, also prepared as a stock solution, was added at concentrations of 50 μM, 75 μM, and 100 μM, respectively, along with comparative additives F1 and F2 at a concentration of 50 μM, respectively, to prepare a copper electroplating solution.

[0127] (3) Preparation and pretreatment of working electrode

[0128] A TSV wafer was prepared by fixing it to a rotating disk electrode (RDE). To improve the wettability inside the via hole, the prepared TSV wafer was immersed in isopropyl alcohol for 600 seconds, and at the same time, air inside the via hole was removed using a pump.

[0129] (4) Apply current

[0130] After fixing the rotating disc electrode to the rotor, it is immersed in a copper electroplating solution and rotated at 1000 rpm at a current density of -1.0 mA / cm² 2 Copper was plated by applying an electric current for 600 seconds.

[0131] (5) Observation of via cross-section

[0132] To observe the cross-section of the wafer more easily, a molding process was performed in which the wafer was placed in an acrylic paste and hardened. After the acrylic had completely hardened, it was removed from the mold, and a sandpaper with an appropriate grid was fixed to a polisher, and the cross-section of the wafer was polished. Subsequently, the cross-section of the vias was observed using a microscope. The captured TSV cross-section images are shown in Figures 3 and 4.

[0133] Referring to Figure 3, it was confirmed that copper was filled without defects inside the via structure when the concentration of additive L2 was 50 μM, 75 μM, and 100 μM, respectively. In addition, by referring to the TSV cross-section when a current was applied for 300 seconds, it was confirmed that copper electrodeposition on the top wall of the via was effectively suppressed, thereby achieving defect-free filling through a bottom-up filling process.

[0134] On the other hand, referring to Figure 4, it was confirmed that when comparative additive F1 or F2 was used as an additive, copper bottom filling did not occur. When comparative additive F1 was used, the amount of copper plated inside the via hole was very small, which means that most of the plating was electrodeposited on the surface of the wafer rather than inside the via hole. When comparative additive F2 was used, it was confirmed that although copper was plated inside the via hole, large, elongated void defects occurred. Through this, it was confirmed that compared to comparative additive F1, which has the central structure of additives L1 and L2, comparative additive F2, which has an ammonium group structure connected to the center of additive L2, is effective in suppressing electrodeposition on the wafer surface, but unlike additives L1 and L2, it has limitations in suppressing copper electrodeposition on the upper wall of the via.

[0135] Experimental Example 4

[0136] In order to determine whether defect-free filling of silicon through-vias can be achieved when the additive L1 prepared in Example 1 above is used as an additive, a TSV filling experiment was performed in the following manner.

[0137] (1) TSV wafer preparation

[0138] A silicon wafer was etched to form a via hole structure with a diameter of 7 μm and a depth of 50 μm (aspect ratio 7:1). A Ti diffusion barrier layer was deposited inside the via hole to a thickness of 100 nm, and a Cu seed layer was deposited on top of it to a thickness of 1.5 μm.

[0139] (2) Electrolyte preparation

[0140] 300 ml of an electrolyte of 1 M CuSO4 + 0.5 M H2SO4 was prepared by placing it in a 400 ml capacity beaker. A copper electroplating solution was prepared by adding a stock solution of NaCl to the prepared electrolyte to a concentration of 1 mM, and adding an additive L1 solution, also prepared as a stock solution, to a concentration of 50 μM.

[0141] (3) Preparation and pretreatment of working electrode

[0142] A TSV wafer was fixed to a rotating disc electrode and prepared. To improve the wettability inside the via hole, the prepared TSV wafer was immersed in isopropyl alcohol for 600 seconds, and at the same time, air inside the via hole was removed using a pump.

[0143] (4) Apply current

[0144] After fixing the rotating disc electrode to the rotor, it is immersed in a copper electroplating solution, and while rotating at 1000 rpm, the current density is -1.5 mA / cm² 2 Copper was plated by applying an electric current for 600 seconds.

[0145] (5) Observation of via cross-section

[0146] To facilitate easier observation of the wafer cross-section, a molding process was performed in which the wafer was placed in an acrylic paste to solidify after the experiment. After removing the completely solidified acrylic from the mold, a sandpaper with an appropriate grid was attached to a polishing machine, and the wafer cross-section was polished. Subsequently, the cross-section of the vias was observed using a microscope. The captured TSV cross-sectional image is shown in Fig. 5.

[0147] Referring to Figure 5, it was confirmed that copper was filled inside the via structure without defects through the bottom filling process when additive L1 was used as an additive.

[0148] The foregoing description of this specification is for illustrative purposes only, and those skilled in the art to which one aspect of this specification pertains will understand that other specific forms can be easily modified without altering the technical concept or essential features described in this specification. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single unit may be implemented in a distributed manner, and components described as distributed may likewise be implemented in a combined form.

[0149] The scope of this specification is defined by the claims set forth below, and all modifications or variations derived from the meaning and scope of the claims and equivalent concepts thereof should be interpreted as being included within the scope of this specification.

Claims

1. An additive for defect-free filling of silicon through-vias comprising a tris-ammonium compound represented by the following chemical formula 1: [Chemical Formula 1] In the above chemical formula 1, R1 to R6 are each independently hydrogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or a substituted or unsubstituted alkenyl group, and L1 to L3 are each independently a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkenylene group, a substituted or unsubstituted alkynylene group, or a substituted or unsubstituted heteroalkylene group, and A1 to A3 are each independently hydrogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted aliphatic hydrocarbon ring, a substituted or unsubstituted aromatic hydrocarbon ring, a substituted or unsubstituted aliphatic heterocycle, or a substituted or unsubstituted aromatic heterocycle. X - is the counterion of ammonium.

2. In Paragraph 1, In the above chemical formula 1, R1 to R6 are each independently hydrogen, or a C1 to C6 substituted or unsubstituted alkyl group, and L1 to L3 are each independently a single bond, or a C1 to C6 substituted or unsubstituted alkylene group, and A1 to A3 are each independently C6~C 30 It is a substituted or unsubstituted aromatic hydrocarbon ring, and X - is a defect-free filling additive for silicon penetrating vias, which is a counterion of ammonium.

3. In Paragraph 1, The above X - is iodide ion (I - ), bromide ions (Br - ), chloride ions (Cl - ), fluoride ion (F - ), iodate ion (IO3 - ), chlorate ion (ClO3 - ), perchlorate ion (ClO4 - ), bromate ion (BrO3 - ), nitrate ions (NO3 - ), nitrite ions (NO2 - ), hexafluoride phosphate ion (PF6 - ), tetrafluoride ion (BF4 - ), sulfate ions (HSO4) - ), methyl sulfate ion (CH3SO4 - A defect-free filling additive for silicon through-vias, selected from the group consisting of ) and combinations of two or more of these.

4. In Paragraph 1, The above tris-ammonium compound is a defect-free filling additive for silicon penetrating vias, wherein the tris-ammonium compound is a compound represented by the following chemical formula 2 or the following chemical formula 3: [Chemical Formula 2] [Chemical Formula 3] 5. A copper electroplating solution comprising an additive for defect-free filling of silicon through-vias according to claim 1.

6. In Paragraph 5, A copper electroplating solution having a concentration of 5 to 1000 μM for the additive used for defect-free filling of the above silicon through-via.

7. In Paragraph 5, The copper electroplating solution described above further comprises one selected from the group consisting of deionized water, a copper ion compound, a supporting electrolyte, a halogen compound, and a combination of two or more of these.

8. In Paragraph 7, The copper ion compound is a copper electroplating solution selected from the group consisting of copper sulfate (CuSO4), copper methanesulfonate (Cu(CH3SO3)2), copper carbonate (CuCO3), copper cyanide (CuCN), copper(II) chloride (CuCl2), copper perchlorate (Cu(ClO4)2), and combinations of two or more of these.

9. In Paragraph 7, The above supporting electrolyte is a copper electroplating solution selected from the group consisting of sulfuric acid (H2SO4), methanesulfonic acid (CH3SO3H), sodium sulfate (Na2SO4), potassium sulfate (K2SO4), boric acid (H3BO3), perchloric acid (HClO4), and combinations of two or more of these.

10. In Paragraph 7, A copper electroplating solution in which the above halogen compound is one selected from the group consisting of hydrochloric acid (HCl), sodium chloride (NaCl), potassium chloride (KCl), hydrogen bromide (HBr), sodium bromide (NaBr), potassium bromide (KBr), hydrogen iodide (HI), sodium iodide (NaI), potassium iodide (KI), and combinations of two or more of these.

11. A copper electroplating method using the copper electroplating solution of paragraph 5.

12. In Paragraph 11, (a) a step of pre-treating a silicon substrate having via holes formed therein; and (b) a step of forming silicon through-vias by plating the pretreated silicon substrate with the copper electroplating solution of claim 5; a copper electroplating method comprising.

13. In Paragraph 12, A copper electroplating method in which the aspect ratio of the above via holes is 2:1 to 50:

1.

14. In Paragraph 12, A copper electroplating method in which the pretreatment of step (a) above is performed by immersing a silicon substrate having via holes formed therein in a solution selected from the group consisting of methanol, ethanol, isopropyl alcohol, and a combination of two or more of these.

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