TW201619445A - Electrodeposition of copper - Google Patents

Abstract

In electrolytic copper plating, an aqueous composition comprising a source of copper ions and at least one alkylene or polyalkylene glycol monoether which is soluble in the aqueous phase and has molecular weight not greater than about 500 for improving the efficacy of other additives such as, for example, levelers and suppressors; and a related plating method.

Description

Electrodeposition of copper

The present invention is generally directed to compositions and methods for electrolytic copper deposition for a variety of applications. One aspect of the invention pertains to an additive incorporated into a copper plating bath to facilitate delivery of a functional compound over a substrate on which electrolytically deposited copper.

Electrolytic copper deposition typically involves depositing Cu from a Cu plating bath containing functional additives such as suppressors, levelers, accelerators, and other additives that affect deposition. Features and mechanisms. Non-limiting examples of Cu plating applications using functional additives include, for example, fabrication of integrated circuits, through-silicon vias (TSV), printed wiring boards (PWB). And Cu plating in wafer level packaging (WLP).

One of the challenges of many Cu plating applications is the high surface tension that makes it impossible to provide ingredients (such as functional additives) throughout the substrate to be plated. A fast, even distribution on the surface.

An example of an additive assisted Cu plating is damascene Cu plating when manufacturing a semiconductor integrated circuit (IC) device such as a computer chip. In view of the increase in circuit speed and circuit density associated with such devices, ultra-large scale integration (ULSI) and very large scale circuits (very-large scale) The size of the interconnect feature in the integration) (VLSI) structure has been significantly reduced. The trend toward smaller device sizes and increased circuit density requires that the size of the interconnect features be reduced and their density increased. The interconnect features are features such as vias or trenches formed in the dielectric substrate, which are then filled with a metal (typically copper) such that the interconnects are electrically conductive. Copper is introduced to replace aluminum to form a connection line and an interconnection in the semiconductor substrate. Copper with better conductivity than any metal other than silver is the metal of choice because copper metallization allows for smaller features and uses less energy to energize. In the damascene process, the interconnect features of the semiconductor IC device are metallized by electrolytic copper deposition.

In the case of semiconductor integrated circuit device fabrication, the substrate is a patterned dielectric film on a semiconductor wafer or chip substrate, for example, on a crucible or a crucible or crucible. Low κ dielectric film. Typically, a wafer has a layer of integrated circuitry (eg, a processor, programmable device, memory device, etc.) built into one or more dielectric layers on a semiconductor substrate. Integrated circuit (IC) devices have been fabricated with submicron holes and trenches, The interconnect structure (hole) and the device (trench) form an electrical connection. These features typically have dimensions on the order of about 200 nanometers or less.

A conventional semiconductor process is a copper damascene system. In other words, this system begins by etching a circuit architecture into a substrate dielectric material. The architecture includes a combination of the above described trenches and holes. Next, a barrier layer is placed on the dielectric to prevent the subsequently applied copper layer from diffusing into the junction of the substrate, and then physical vapor deposition or chemical vapor deposition of the copper seed layer (copper seed) Layer) to provide electrical conductivity for subsequent electrochemical processes. Copper filled into holes or trenches in the substrate can be plated (eg, electroless or electrolytic), sputtered, plasma vapor deposited (PVD), and chemical vapor deposited. (CVD) deposition. Electrochemical deposition is generally considered to be the best method of applying copper because it is more economical than other deposition methods and perfectly fills in interconnect features (often referred to as "bottom up" growth or superfilling (superfilling) )). After deposition of the copper layer, excess copper is removed from the dielectric plane by dielectric mechanical polishing, leaving only copper in the interconnected features of the dielectric etch. Subsequent layers are fabricated in a similar manner before the final semiconductor package is assembled.

Copper plating methods need to meet the stringent requirements of the semiconductor industry. For example, copper deposits need to be uniform and perfectly filled into the small interconnect features of the device (eg, having openings of 100 nm or less).

Electrolytic copper systems have been developed which rely on so-called "superfilling" or "bottom-up growth" to deposit copper into various aspect ratio features. Overfilling Fill the feature up and down, rather than having all of its surfaces at the same rate, to avoid seams and pinching off that can result in voiding. A multi-component system for overfilling consisting of an inhibitor and an accelerator as an additive has been developed, see U.S. Patent No. 8,388,824 to Paneccasio et al.

The good distribution of composition becomes particularly critical when overfilling the sub-micron interconnect features of semiconductor integrated circuit devices. The problem has become more and more difficult, as the size of interconnects has become more subtle in recent years (eg, <100 nm, <50 nm, and <20 nm) and will continue to become finer (ie, <10 nm, for example, ~ 7nm).

Thus, in short, the present invention relates to a composition for electroplating copper, comprising a source of metal ions and an additive which is a low molecular weight alkylene glycol ether or a polyalkylene glycol ether ( Polyalkylene glycol ether) or a mixture of these; and, related to the plating method. Preferably, the ether has a molecular weight of less than 500 g/mole.

Briefly, therefore, the present invention relates to an aqueous composition comprising a source of copper ions and at least one alkylene glycol ether or polyalkylene glycol ether which is soluble in the aqueous phase. And having a molecular weight of no greater than about 500 to promote the effectiveness of other additives such as, for example, leveling agents and inhibitors.

In one embodiment, the ether has the following general structure (1) or (2): R ¹ O[CH ₂ CHR ² O] _n R ³ structure (1)

Wherein R ¹ is a substituted or unsubstituted alkyl, cycloalkyl or aryl group; R ² is H or a substituted or unsubstituted alkyl group having, for example, 1 to 3 carbon atoms; n is The compound is not so large as an integer that interferes with plating and is compatible with the bath; in one embodiment, n is an integer from 1 to 7, such as 1 to 6, 1 to 5, or 1 to 4 ; and R ³ is H.

R ¹ O[CH ₂ CHR ² O] _n [CH ₂ CHR ⁴ O] _m R ³ structure (2)

Wherein R ¹ is a substituted or unsubstituted alkyl, cycloalkyl or aryl group; R ² is H or a substituted or unsubstituted alkyl group having, for example, 1 to 3 carbon atoms; R ⁴ is H or a substituted or unsubstituted alkyl group having, for example, 1 to 3 carbon atoms, R ⁴ is different from R ² ; n and m are such that the compound is not so large as to hinder electroplating, and is allowed to react with the bath (bath) a compatible integer; in one embodiment, n and m are integers from 1 to 7, such as from 1 to 6, from 1 to 5, or from 1 to 4; and R ³ is H.

In another aspect, the present invention is directed to an electroplating method for electrodepositing copper on a substrate comprising a copper-based or cobalt-based surface, the method comprising providing an electrolytic circuit, the package thereof An anode comprising a power source, in contact with the electrodeposition solution, and a cathode containing the surface of the substrate and in contact with the electrodeposition solution; and an electrolysis current is passed through the circuit to deposit copper on the cathode; wherein the electrodeposition composition has the above Glycol ether.

Other purposes and features will be apparent from the following sections.

Figure 1 is a diagram showing a baseline make-up acid electrolytic plating solution (MULA) and a tripropylene glycol n-butyl ether (additional concentration of 1 g/L to 10 g/L). Butyl ether) (TPB) to the surface tension of the dynamic surface tension test of the solution in MULA solution relative to the surface age (ie, time); Figure 2 includes the bath of low acid copper plating solution Dynamic surface tension mapping of (MULA) solution, MULA solution with inhibitor added, and MULA solution containing inhibitor and two different concentrations of TPB (similar to Figure 1); Figure 3 includes dynamic surface tension mapping (similar to Figure 1 with 2) compare MULA solution containing inhibitor with MULA solution containing inhibitor and TPB, and MULA solution containing 10g/L TPB but no inhibitor; Figure 4 includes dynamic surface tension mapping (similar to Figure 1 to 3)), containing different concentrations of tripropylene glycol methyl ether (TPM), tripropylene glycol propyl ether (TPP), and tripropylene glycol (tripropylene glycol) N- Butyl ether) (TPB) MULA solution; Figure 5 is a plot of the MULA solution containing the inhibitor and the dynamic contact angle of the MULA solution containing the inhibitor and TPB; Figure 6 is a diagram showing the tripropylene glycol methyl ether Dynamic contact angle of (TPM), tripropylene glycol n-propyl ether (TPP) and TPB MULA solution; Figure 7 shows MULA plating solution containing accelerator and inhibitor, and the same as the former But also contains a chronopotentiometric polarization curve of the plating solution of TPB; FIG. 8 is a cross-sectional photomicrograph of the trench filled by electrodeposition of several plating solutions of Example 8; Figure 9 is a series of bar graphs showing that each contains TPM, TPP, TPB, dipropylene glycol propyl ether (DPP), dipropylene glycol butyl ether (DPB), and Static surface tension measured by various compositions of propylene glycol butyl ether (PB) in MULA solution; Figure 10 shows MULA solution containing inhibitor, And dynamic surface tension curves of four additional formulations consisting of MULA compositions containing inhibitors and different concentrations of TPP; Figure 11 shows a dynamic surface tension curve similar to that of Figure 10, but the solubilization used in the test Hydrotrope is a TBP substitution of TPP and a different concentration range; Figure 12 shows a dynamic surface tension curve similar to those of Figures 10 and 11, but the hydrotrope used in the test is propylene glycol n-butyl ether (propylene). Glycol n-butyl ether); Figure 13 shows the dynamic surface tension curves selected from Figures 10 through 12 for comparison of MULA solutions containing inhibitors, and TPB, propylene glycol butyl ether (PB) containing inhibitors and concentrations indicated. Or a TUP MULA solution; Figure 14 shows a dynamic surface tension curve similar to that of Figure 13, but a different combination of hydrotrope and solubilizer concentration; Figure 15 includes a bar graph similar to Figure 9. This is a comparison of the static surface tension of a MULA bath containing TPB with a MULA bath containing three different solubilities (each consisting of ethoxylated TPB); Figure 16 is a diagram showing each containing TPB and Three different solubilisates ( The static surface tension of the solution of ethoxylated TPB is relative to the humectant (solubilizing agent) concentration; Figure 17 shows the inclusion of accelerator, inhibitor, leveling agent and TPB (ethoxylated at different EO/TPB ratios) Chronopotentiometric polarization curve of the solution; Figure 18 is a diagram containing copper sulfate (40g / L Cu ⁺⁺ ), sulfuric acid (10g / L), chloride (50ppm), and different concentrations The surface tension of the dynamic surface tension test of the solution of the low copper electrolyte of the reaction product of TPB and 1.5 mol ethylene oxide relative to the surface age; Figure 19 is a reproduction of low copper containing an alkoxylated amine inhibitor (200 ppm) a low copper acid plating solution and a polarization curve from a chronopotentiometric test of a low copper solution containing an inhibitor and alkoxylated butanol (7.5 g/L); FIG. 20 is a dynamic surface The tension is relative to the surface age for the two low copper electrolyte solutions each containing an alkoxylated amine inhibitor (200 ppm) and further containing alkoxylated butanol, the same solution as described in Figure 19; 21 series A series of surface tension diagrams for a solution containing a low copper electrolyte solution containing copper sulfate, sulfuric acid, chloride ions, and different concentrations of alkoxylated butanol (refer to the previous figures); and Figure 22 shows relative surface tension Additional maps on surface age are directed to various plating solutions containing low acid electrolytes containing different combinations of inhibitors and hydrotropes.

This invention relates to compositions and methods for depositing metals such as copper or copper alloys. The composition of the present invention comprises an additive which assists in the rapid and uniform dispersion of the functional additive over the entire surface of the substrate to be plated. The additive compound is an alkylene glycol monoether or a polyalkylene glycol. Monoether). It is understood that these additive compounds act as hydrotropes in combination with other functional additives and equalize the uniform distribution of the entire substrate. As used herein, the term "hydrotrope" refers to a glycol ether which promotes the rapid and uniform distribution of functional additives throughout the surface of the cathode (including the surface of the trench and the pores). It is not necessary to specify an additive that enhances the solubility of other additives, although in some instances it may also serve this purpose. For example, it can easily increase the solubility of the inhibitor in the aqueous phase.

The process of the present invention is accomplished by incorporating certain hydrotrope compounds into an electrolytic plating solution. These compounds include certain alkylene glycol ethers and polyalkylene glycol ethers. A preferred class of additives are low molecular weight polyalkylene glycol ethers.

Surprisingly, the inventors have discovered that the addition of certain low molecular weight hydrotrope compounds to copper electrolytes can result in rapid and uniform distribution of functional components (such as inhibitors and accelerators) throughout the surface of the substrate. And the advantage of reduced surface tension (as shown in the examples and figures herein). Hydrotrope compounds generally have a relatively low molecular weight and have a molecular weight of, for example, less than 500 g/mole, such as less than 350 g/mole, for example, 117 to 500 or 117 to 350 g/mole. In certain preferred embodiments of the invention, the hydrotrope compound has a molecular weight of less than 250 g/mole, for example, from 117 to 250 g/mole.

Hydrotrope compounds suitable for use in the compositions and methods of the present invention include alkylene glycol ethers and polyalkylenes having the following general structure (1) or (2). Glycol ether): R ¹ O[CH ₂ CHR ² O] _n R ³ structure (1)

Wherein R ¹ is a substituted or unsubstituted alkyl, cycloalkyl or aryl group; R ² is H or a substituted or unsubstituted alkyl group having, for example, 1 to 3 carbon atoms; n is The compound is not so large as an integer that interferes with plating and is compatible with the bath; in one embodiment, n is an integer from 1 to 7, such as 1 to 6, 1 to 5, or 1 to 4 ; and R ³ is H.

R ¹ O[CH ₂ CHR ² O] _n [CH ₂ CHR ⁴ O] _m R ³ structure (2)

Wherein R ¹ is a substituted or unsubstituted alkyl, cycloalkyl or aryl group; R ² is H or a substituted or unsubstituted alkyl group having, for example, 1 to 3 carbon atoms; R ⁴ is H or a substituted or unsubstituted alkyl group having, for example, 1 to 3 carbon atoms, R ⁴ is different from R ² ; n and m are such that the compound is not so large as to hinder electroplating, and is allowed to react with the bath (bath) a compatible integer; in one embodiment, n and m are integers from 1 to 7, such as from 1 to 6, from 1 to 5, or from 1 to 4; and R ³ is H.

A currently preferred subtype is defined as a monoether having such a structure.

In the structure (1), n is preferably from 2 to 6, more preferably from 2 to 5. In the structure (2), the sum n+m is preferably from 2 to 6, more preferably from 2 to 5.

In certain different embodiments of structure (1), R ² is a compatible hetero substituent, for example, CH ₂ OH. In certain different embodiments of structure (2), R ² and/or R ⁴ may be a compatible hetero substituent, for example, CH ₂ OH, or others.

In various preferred embodiments of the invention, the hydrotrope additive is an alkylene glycol ether or a polyalkylene glycol ether having the following general structure (3). :R ¹ O[CH ₂ CHR ² O] _n R ³ structure (3)

Wherein R ¹ is a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms; R ² is a methyl group; R ³ is hydrogen; and n is an integer of 1 to 3 inclusive.

Particularly preferred is a polyalkylene glycol ether of structure (III) wherein R ¹ is n-propyl or n-butyl, R ² is methyl, R ⁴ is hydrogen, and n is 1 or 3. Compound. For example, a preferred additive for the present invention is tripropylene glycol butyl ether, such as structure (4).

This compound can be obtained, for example, from Dow Chemical, Named Dowanol® TPnB. Although n-butyl ether is depicted, the commercial product includes a mixture of isomers containing n-butyl and other butyl group types (i.e., secondary butyl, isobutyl, and/or tertiary butyl).

Other particularly preferred additives of the present invention include tripropylene glycol n-propyl ether (TPP, structure (5)) and propylene glycol n-butyl ether (PB, structure). (6)).

The two glycol ethers are commercially available from Dow Chemical under the trademarks Dowanol® TPnP and Dowanol® PnB. The propyl ethers may also include a mixture of n-propyl and isopropyl groups.

In a further embodiment of the invention, a mixture of glycol ether additives can be used in the copper electroplating bath. Thus, for example, it may be advantageous to combine two or more propylene glycol ethers, or a combination of a propylene glycol ether and an ethylene glycol ether.

The glycol ether additive is typically present in the electrolytic copper plating bath at a concentration of at least about 1 g/L, for example, from 1 to 20 g/L or from 1 to 5 g/L. Preferably, the glycol ether additive is present at a concentration of at least about 3 g/L or at least about 5 g/L, more typically from about 5 to about 20 g/L. Certain of these glycol ethers in certain embodiments The concentration of the species is maintained below a maximum of about 20 g/L because exceeding this maximum causes the glycol ether additive to interfere with the characteristic Cu filling. More preferably, the glycol ether concentration ranges from about 5 to about 15 g/L or from about 5 to about 10 g/L. Excessive concentrations are also likely to result in lower cloud points, which can cause separation of components in the electrolyte.

It is believed that the glycol ether additive of the present invention reduces the surface tension of the solution to a value close to that of the Cu substrate. When a cobalt seed layer is used in place of the Cu seed layer, the surface tension of the plating solution is preferably matched to the surface tension of the Co substrate (as close as practicable). Reducing the surface tension helps to promote the rapid and uniform distribution of ingredients such as functional additives throughout the substrate, removing air bubbles from the surface, and enabling the plating bath and its components to enter the characteristics of the substrate. It is a challenge to immediately deliver the functional additive components of the plating solution to the smaller features of today's substrates; it is expected that this challenge will be even greater as these features are expected to be smaller with each technological node in progress. . In addition, as the substrate size continues to increase, for example, 300 mm or 450 mm wafers, the problems associated with uniformly delivering the plating solution and its components to the entire substrate are more serious.

A variety of low molecular weight monofunctional alkylene glycol ethers and polyalkylene glycol ethers suitable for use in the present invention are commercially available. A preferred additive of the invention, tripropylene glycol n-butyl ether, is sold under the trade name Dowanol® TPnB as a mixture of isomers, referred to herein as TPB.

An electrolytic deposition composition of the invention comprises glycol ether, Cu Ion source, acid, water, and one or more functional additives. In order to fill the submicron features of the semiconductor integrated circuit device, the electrolytic deposition composition of the present invention generally includes a glycol ether, a copper ion source, a chloride ion, an acid, an accelerator, an inhibitor, and a leveling agent. It may further comprise more than one inhibitor, or more than one accelerator, or more than one leveler.

The compositions of the present invention are useful for electrodeposition of copper in various applications involving electronic circuit fabrication. For example, the composition can be used in processes such as submicron interconnects in a superfilling semiconductor integrated circuit wafer, filled vias (TSVs), holes used to plate printed circuit boards and filled therein, and Wafer level packaging. The feature of the present invention for overfilling a wafer IC substrate in damascene Cu plating is described later. General methods, as well as suitable accelerators, inhibitors, and leveling agent additives, are disclosed in U.S. Patent Nos. 6,776,893; 7,303,992; 7,316,772; 8,002,962; and 8,388,824. The disclosures of these patents are hereby incorporated by reference. The accelerator and inhibitor components in the compositions of the present invention advantageously promote the so-called "superfilling" (relative to conformal plating) of the interconnect features from bottom to top. Way to cooperate.

In order to achieve defect-free filling, ie, void and seam, the deposition rate at the bottom should greatly exceed the deposition rate of the sidewall. For example, during copper metallization, the rate of copper deposition along the bottom (ie, the rate of growth from bottom to top or vertical) is preferably at least one level faster than the rate of copper deposition along the sidewall (ie, lateral or horizontal growth rate). Amplitude. Such The relative deposition rate is especially important for sub-micron features of a semiconductor integrated circuit device.

The accelerator may include an organic sulfur compound. The preferred organic sulfur compounds are currently known to be water-soluble organic divalent sulfur compounds, as disclosed in U.S. Patent No. 6,776,893, the entire disclosure of which is incorporated herein by reference. A preferred accelerator is 3,3'-dithiobis-1-propanesulfonic acid disodium salt having the following structure.

Or 3-mercaptopropane sulfonic acid (sodium salt).

The organic sulfur compound may be added at a concentration of between about 20 mg/L and about 200 mg/L (ppm), typically between about 40 mg/L and about 100 mg/L, such as between about 50 mg/L and 70 mg. Between /L. In a preferred embodiment, the organosulfur compound is 3,3'-dithiobis(1-propanesulfonic acid) disodium salt (or an analog or a derivative or a free acid) at a concentration of About 60 mg / L.

Inhibitors typically include a polyether bonded to an alcohol moiety by, for example, ethoxylation of the corresponding alcohol, but may be covalently bonded to the base moiety by the presence of a plating solution. Improved bottom-up filling of the polyether group (more preferably nitrogen-containing). One class of useful inhibitors includes polyether groups covalently bonded to an amine moiety. For some In an embodiment, the invention is based on the inhibitors disclosed in U.S. Patent No. 6,776,893 or 7,303,992 to Panecs.

A variety of electrolytic copper deposition compositions are available, including all low acid (e.g., 10 g/L), medium acid (e.g., 80 g/L), and high acid (e.g., 200 g/L) baths. An exemplary electrolytic copper plating bath includes an acid copper electroplating bath, for example, copper fluoroborate, copper sulfate, and other copper metal complexes such as copper methane sulfonate and hydroxyethyl. Based on copper hydroxyethyl sulfonate. Preferred sources of copper include copper sulfate (in a sulfuric acid solution) and copper methanesulfonate (in a methanesulfonic acid solution).

In embodiments where the copper source is copper sulfate and the acid is sulfuric acid, the concentration of copper ions and acid can vary over a wide range; for example, from about 4 to about 70 g/L copper and from about 2 to about 225 g/L sulfuric acid. For this, the compounds of the invention are suitable for use in different acid/copper concentration ranges, such as high acid/low copper systems, low acid/high copper systems, low acid/low copper systems, and medium acid/high copper systems.

In other embodiments, the copper source comprises copper methane sulfonate and the acid system comprises methane sulfonic acid. The use of copper methane sulfonate as a source of copper results in a greater concentration of copper ions in the electrolytic copper deposition bath (relative to other sources of copper ions).

When copper methane sulfonate is used as the source of copper ions, acid pH adjustment is preferably carried out using methanesulfonic acid. This avoids the introduction of unnecessary anions by electrolytic deposition chemistry. When methanesulfonic acid is added, its concentration can be higher than about 1 g/L. It has been found that the electrolytic deposition composition of the present invention preferably has a low acid concentration The degree is, for example, between about 1 g/L and about 50 g/L, or between about 5 g/L and about 25 g/L, for example, about 10 g/L.

Chloride ions can also be used in the bath at levels up to a level of no more than 100 mg/L (about 100 ppm), such as from about 10 mg/L to about 90 mg/L (10 to 90 ppm), for example, about 50 mg/L (about 50ppm).

Exemplary plating solutions include "low acid" solutions containing copper sulfate (30-60 g/L Cu ⁺⁺ ), sulfuric acid (5-25 g/L), and chloride ions (35-70 ppm), for example, 40 g/L. Cu ⁺⁺ , 10 g / L sulfuric acid, and 50 ppm chloride ion; and, "low copper" solution having the same concentration range of acid and chloride as the "low acid" solution but containing only 3 to 20 g / L, preferably 3 Up to 10 g/L Cu ⁺⁺ , for example, 5 g/L Cu ⁺⁺ , 10 g/L sulfuric acid, and 50 ppm chloride ion.

In certain embodiments, the invention utilizes a leveling agent as disclosed in U.S. Patent No. 8,002,962 or U.S. Patent No. 8,388,824. A variety of additives are commonly used in the bath to provide the desired surface finish and metallurgy of copper metallization. More than one additive is typically used to achieve the desired function. At least two additives or three are generally used to initiate bottom-up filling of the interconnect features and to improve the metallurgical, physical and electrical properties (such as electrical conductivity and reliability) of the metal. Additional additives (usually organic additives) include grain refiners and secondary brighteners and polarizers to inhibit dendritic growth, improve uniformity, And reduce defects.

The "wafer" mentioned in the present invention is for the integrated body A semiconductor substrate of any of various manufacturing states in the fabrication of the road. A standard semiconductor wafer system 200, 300, or 450 mm that is intended for use in certain embodiments of the present invention.

Electroplating equipment for electroplating semiconductor substrates is known and described in the literature. The type of equipment is not closely related to the present invention.

Bath additives are suitable for use in combination with membrane technology developed by various tool manufacturers. In this system, the anode can be isolated from the organic bath additive by a membrane. The purpose of separating the anode from the organic bath additive is to minimize oxidation of the organic bath additive on the surface of the anode.

The cathode substrate and the anode are electrically connected by wires and connected to a power source, or more directly to an output terminal of a rectifier that converts a.c. current into d.c. Electrons supplied to the cathode substrate in the circuit by direct current or pulse current reduce copper ions in the plating solution to plate copper metal on the cathode surface. The oxidation reaction takes place at the anode. The cathode and anode can be arranged horizontally or vertically in the tank.

During operation of the electroplating system, a pulse current, a direct current, a reverse periodic current, or other suitable current may be used. The maintenance of the temperature of the electrolytic solution may use a heater/cooler to remove the electrolytic solution from the storage tank and through the heater/cooler and then to the storage tank.

Electrolytic conditions such as applied voltage, current density, solution temperature, and flow conditions are substantially the same as those used in conventional electrolytic copper plating methods. For example, the bath temperature is typically about room temperature, such as about 15 to 27 °C. The current density is typically up to about 20 A/dm ² , such as about 10 A/dm ² , and is typically from about 0.2 A/dm ² to about 6 A/dm ² . Preferably, the anode to cathode area ratio is about 1:1, but this can vary widely, for example from 1:2 to 2:1. The process also employs mixing in the electrolytic plating bath, which may be provided by agitation or preferably by a recycle stream of the electrolytic solution through the recycle of the tank.

The high purity of the copper deposited by the electrolytic copper electroplating composition of the present invention promotes rapid annealing, even at room temperature. The high-purity copper deposition of Saskatchewan facilitates electromigration resistance and thus improves the reliability of the device. The need for a more complete and uniform distribution of copper plating compositions and functional additives is critical at the 32 nm and 22 nm nodes (i.e., the entrance dimensions of the interconnect features are 32 nm or 22 nm, respectively) and, moreover. The process is operable to fill an entry dimension of less than 100 nm, less than 50 nm (eg, 20 to 50 nm), <30 nm (eg, 10 to 30 nm), < 20 nm (eg, 10 to 20 nm), or <10 nm (eg, 5) a sub-micron interconnect feature of -10 nm) having a seeded feature having an aspect ratio of at least about 3:1, preferably at least about 4:1, more preferably at least about 5:1. Or even greater than or equal to about 8:1.

The metallization at the time of initial deposition is in a state in which it undergoes recrystallization, which usually causes individual copper grain size to grow and which reduces the resistivity of deposited copper. The wafer manufacturer can anneal the copper metallized wafer to a temperature of about 200 ° C for about 30 minutes to stabilize the crystal structure. Electrolytic copper electricity by the present invention has been found The high purity copper deposited by the plating composition undergoes relatively rapid recrystallization at room temperature, wherein the copper deposition resistance decreases in an hour.

As mentioned, the alkylene glycol ether or polyalkylene glycol ether additive is preferably a small molecule, for example, having a molecular weight of less than 500. Preferably, R ² is an alkyl group, more preferably a methyl group. Molecules contain a greater proportion of PO units, which are generally more effective at reducing the static and dynamic surface tension of the plating solution and thus promote the distribution of functional additives throughout the surface of the cathode substrate. However, increasing the number of PO units reduces solubility and lowers the cloud point. Based on this, where R ² = methyl (or higher alkyl), the n values in structures (1) and (2) are between 1 and 3, and the structure (2) The sum m+n is between 3 and 6, more preferably between 3 and 5. The nature of R ¹ also affects solubility, which generally decreases with the number of carbon atoms in the substituent. There is an EO group, especially a block configuration (wherein one or more PO units are bonded to R ¹ -O and one or more terminal units of the EO unit are attached away from R ^{The 1} -O bond to the PO structure) enhances solubility and increases the cloud point. However, while the EO unit promotes solubility, it detracts from the ability of the molecule to reduce surface tension.

In order to be able to formulate an electroplating bath having the desired concentration of the wetter additive, a good cloud point, and the desired surface tension of the plating solution, it is preferred to select in some applications. a polyalkylene glycol ether of the structure (2), wherein R ² is a methyl group, R ⁴ is H, an n value is 1 or 2, and a value of m+n is 3 to 6, preferably 3 to 5. A particularly desirable structure can be prepared by the composition of the ethoxylated structure (1). In ethoxylation, the comparison of EO to structure (1) is preferably defined between about 0.2 and about 2.0, for example, 0.5 EO, 1.0 EO or 1.5 EO. Thus, the desired degree of ethoxylation results in a mixture of species of structure (2) wherein R ² is methyl, R ⁴ is H, n is 2 or 3, and m* (average m-value in the mixture) is Between about 0.2 and about 0.8, or between about 0.8 and about 1.2, or between about 1.2 and about 1.8.

When R ⁴ is H, the m value in the structure (2) and the m* value in the mixture of the structure (2) can be further higher than the above preferred values, but the wetting agent promotes rapid superfilling of the semiconductor. The ability of the submicron features of an integrated circuit device will decrease as the molecular weight increases. It may be noted that the basic structure of an alkylene glycol wetting agent is similar to a high molecular weight polyalkylene glycol ether typically used as an inhibitor in submicron features of a filled semiconductor wafer. . Thus, as the length of the polyalkylene oxide chain increases beyond 5 or 6 alkylene oxide repeating units, structures (1) and (2) will begin to have Inhibitor properties and play this role in the plating bath. Although polyalkylene glycol ether wetting agents are still poor inhibitors compared to larger polyalkylene glycol ethers often selected as inhibitors in damascene plating, electroplating A higher concentration of humectant in the bath will begin to substantially help inhibit current flow along the surface of the cathode. Although high molecular weight inhibitors have a strong inhibitory effect (per unit concentration in the plating bath), the concentration of the low molecular weight wetting agent must be relatively higher (if it is intended to substantially reduce the surface tension to substantially promote the functionality of the inhibitor) The additive is distributed throughout the surface of the cathode). For example, the desired concentration of the high molecular weight inhibitor can generally be from about 10 to about 500 mg/L, more typically from 100 to 400 mg/L. In contrast, as noted above, the minimum concentration of humectant is generally at least about 1 g/L (i.e., 1000 mg/L), typically preferably from 3,000 to 5,000, or even 10,000 or 20,000 mg/L. These concentrations are sufficient to have a significant inhibitory effect, wherein the value of n or m+n is significantly higher than the above preferred range. Even at 400-600 ppm, conventional inhibitors can interfere with proper gap filling of the sub-micron features of the semiconductor integrated circuit device. In addition, the presence of polyalkylene glycol ether hydrotropes, especially at high values of m and m+n, results in conformal plating, followed by seams and Void.

Although the ability of the humectant to reduce the surface tension varies with the nature of R ¹ and the ratio of m+n to m/n in the molecule, as long as the wetting agent is to substantially affect the surface tension, even the most effective wetting agent must It is used at a concentration substantially higher than the concentration of the conventional inhibitor.

Furthermore, it has been observed that increasing the number of ethylene oxide units in the alkylene oxide wetting agent increases the solubility and increases the cloud point of the electrolytic plating solution containing the same. Increasing the number of EO repeating units also reduces the effectiveness of the molecule as a wetting agent. The reduction of the humectant unit on surface tension may require further increase in humectant concentration to achieve the desired distribution of functional additives. This increase in concentration may degrade the humectant effect and excessively inhibit the passage through the cathode table. The electrolysis current of the surface. If the inhibition is too strong, the accelerator may no longer effectively deactivate the inhibitor (at the bottom of the submicron trench or hole), thereby absorbing the ability of the plating solution to overfill these features and aggravating conformal plating ( The tendency of conformal plating and the consequent seams and voids.

Therefore, factors affecting the choice of the chain length of the alkylene oxide and the concentration of the wetting agent in the plating solution are easily conflicted. The structure (1) compound can effectively reduce the surface tension, but has a limited solubility and a low cloud point, which further decreases as the value of n increases to >3. Structures with longer EO chains (2) compounds can effectively increase solubility and cloud point and allow higher concentrations of humectants to reduce surface tension, but increase the risk of excessive inhibition and void formation; and have shorter EO chain lengths The compound of structure (2) may have limited solubility and reduce the cloud point of the solution, but it is better (in per unit) to reduce the surface tension and achieve the desired function with a lower humectant concentration that avoids excessive inhibition. Distribution of sexual additives. For most applications, it has been found that the value of n in structure (1) and the value of m+n in structure (2) are preferably in the range of 3-5 as outlined and detailed above.

A preferred inhibitor for use in the compositions and methods of the present invention is described in U.S. Patent 7,303,992, incorporated herein by reference. Preferred inhibitors include polyethers bonded to the nitrogen of the nitrogen-containing species. More preferably, the polyether comprises a propylene oxide (PO) repeating unit and an ethylene oxide (EO) repeating unit having a PO:EO ratio of between about 1:9 and about A combination between 9:1, and the inhibitor compound as a whole has a molecular weight of between 1000 and 30,000. Especially good inhibitors include Tetraalkoxylated alkylene diamine. In these and other alkoxylated amine inhibitors, the molecular weight is preferably between about 1000 and about 10,000 and the PO:EO ratio is preferably between about 1.5:8.5 to 8.5:1.5, 3:7 to 7:3. , or 2:3 to 3:2. The concentration of the alkoxylated amine inhibitor in the electrolytic plating solution is preferably between about 40 mg/L and about 250 mg/L.

The alkylene glycol component of the salt electroplating solution is associated with the inhibitor by hydrogen (in combination with water) and thus acts as a carrier to promote distribution of the inhibitor throughout the surface of the cathode.

Typical alkylene glycol monoethers and polyalkylene glycol monoethers which are compatible with structure (1) and which can be used in novel electrolytic plating solutions, including propylene glycol ethers such as propylene glycol Propylene glycol methyl ether, dipropylene glycol methyl ether, tripropylene glycol methyl ether, propylene glycol n-propyl ether, propylene glycol n-butyl Propylene glycol n-butyl ether, dipropylene glycol n-butyl ether, and tripropylene glycol n-butyl ether. Glycol ethers are not so preferred but can also be used. These include, for example, diethylene glycol ethyl ether, diethylene glycol methyl ether, diethylene glycol n-butyl ether (commercially available, for example, Butyl Carbitol (Dow)), ethylene glycol propyl Ether), and ethylene glycol n-butyl ether (commercially available, for example, Butyl Cellosolve (Dow)). Particularly preferred are tripropylene glycol n-propyl ether (TPP) and tripropylene glycol n-butyl ether (TPB). Propylene glycol ethers and polypropylene glycol ethers are generally preferred over glycol ethers.

However, in the above-listed commercially available alkylene glycol monoethers and polyalkylene glycol monoethers, the n value in the structure (1) is 2 or 3. In response to the use of a structure in which R ⁴ is H and m is 1 or 2 (2) a polyalkylene glycol ether can be found to enhance solubility and cloud point, the present invention further includes an alkylene glycol ether and a ring The oxyethylene reaction is carried out to increase the m value to produce a mixture in which m* (the average value of m) is in the above preferred range.

Although R ⁴ is not H in the structure (2), ethoxylation can effectively improve the solubility and cloud point of this species. More specifically, wherein R ² and R ⁴ are each an alkyl group, or a structure wherein R ² is H and R ⁴ is an alkyl group; (2) an alkylene glycol ether which is reactive with ethylene oxide , the EO structure (2) ratio is from 0.2 to 2.0, for example, from 0.5 to 2.0, or from 1.0 to 2.0, more specifically from 0.2 to 0.8, from 0.8 to 1.2, or from 1.2 to 2.0 to produce the structure (8) product: R ¹ O [CH ₂ CHR ² O] _n [CH ₂ CHR ⁴ O] _m [CH ₂ CH ₂ O] _p R ³ structure (8)

Wherein R ² is H or a substituted or unsubstituted alkyl group, R ⁴ is a substituted or unsubstituted alkyl group, R ³ , m, and n are as defined above, and p is a structure ( 8) The molecular weight is not more than an integer of 500. This additional embodiment further comprises a mixture comprising molecules of structure (8) having different p values, wherein p* (average number of p values in the mixture) is such that the number average molecular weight of the mixture of structures (8) is not more than 500, Good is no more than about 300.

Preferably, the p* is between 0.2 and 2.0, or between 0.5 and 2.0, more preferably between 0.2 and 0.8, between 0.8 and 1.2, or between 1.2 and 2.0.

A particularly preferred hydrotrope is one of the molar structures (1) alkylene glycol ether and 0.2 to 0.8 moles (preferably about 0.5 moles), 0.8 to 1.2 Mohr (preferably about 1.0 mole), or an ethylene oxide reaction between 1.2 and 2 moles (preferably about 1.5 moles). Reaction with 0.2 to 0.8 moles of ethylene oxide produces a mixture of structure (1) and structure (2), where m* (average m-value in the mixture (as 0 in structure (1)) Between about 0.2 and about 0.8. Reaction with 0.8 to 1.2 moles of ethylene oxide produces a mixture of species of structure (2) wherein the m* is between 0.8 and 1.2. Reaction with 1.2 to 2 moles of alkylene oxide produces a mixture of species of structure (2) wherein the m* is between 1.2 and 2.

The present invention is particularly directed to a novel method for electrodepositing copper on a substrate comprising a semiconductor integrated circuit device having sub-micron features. In the method, an electrolytic circuit is provided to include a power source, an anode in contact with the electrodeposition solution, and a cathode including a seed layer on the substrate and in contact with the electrodeposition solution. Wherein the power source is a.c., the circuit further comprises a rectifier to convert the current into d.c. The electrolysis current is passed through a circuit to deposit copper at the cathode. Electrodeposition solution Copper ion source, inhibitor, and one or more glycol ethers or alkoxylated glycol ethers (as defined herein) are as hydrotropes and / or humectant.

According to the above description and the examples below, the acid copper plating solution is formulated to exhibit a dynamic surface tension of not more than about 55 dynes/cm (at 25 ° C) and static surface tension. It is no more than about 50 dynes/cm (at 25 ° C). In accordance with the present invention, the copper electroplating bath can be formulated to have a dynamic surface tension of substantially no greater than a static surface tension, for example, in the range of 35 to 45 dynes/cm (at 25 ° C).

Example 1

The dynamic surface tension of various concentrations of tris(propylene glycol)butyl ether (TPB) in sulfuric acid (10 g/L) was measured in a low acid Cu plating make up electrolyte (MULA). The concentration of ions (50 ppm) and copper sulfate was such that a Cu ion concentration of 40 g/L was provided. The results are shown in Figure 1.

Example 2

The dynamic surface tension of various concentrations of TPB in a low acid Cu plating bath electrolyte (MULA) containing a tetraalkoxylated ethylenediamine inhibitor was measured. The results are shown in Figures 2 and 3. The addition of 10 g/L TPB resulted in a significant decrease in both dynamic and static surface tension. In the inhibitor (200ppm) + TPB mixture, TPB pair Surface tension has a major impact.

Example 3

The dynamic surface tension imparted to the MULA solution by TPB was measured and compared to TPM (tris(propylene glycol) methyl ether) and TPP (tris(propylene glycol) propyl ether). The results are shown in Figure 4. Among the three, TPB gives the lowest surface tension.

Example 4

A comparative chronopotentiometry test was performed on the electrolytic plating solution. The first one is CuSO ₄ (40g/L Cu ⁺⁺ ), sulfuric acid (10g/L), and chloride ion (50ppm), SPS accelerator (63mg/L), and alkoxylated amine inhibitor (200mg/L). The MULA plating solution is composed. The second plating solution was the same as the first but it also contained tripropylene glycol n-butyl ether (10 g/L). The polarization curve is reproduced in Figure 7. It can be seen that the addition of TPB has no substantial effect on polarization. Thus, the addition of 10 g/L of TPB neither affects the effectiveness of the inhibitor nor causes oversuppression that would lead to conformal plating using the second plating solution.

Example 5

The dynamic contact angle imparted to the surface tension of the electrolyte by TPB in the presence of an alkoxylated amine inhibitor (200 ppm) was measured and is shown in FIG. In Figure 5, the triangle data represents MULA+ The 200 ppm inhibitor, circle data line represents MULA + 200 ppm inhibitor + 10 g / L TPB. The addition of 10 g/L TPB significantly reduced the contact angle, i.e., decreased by about 20 degrees.

Example 6

The dynamic contact angle of the surface tension of the electrolyte (MULA) imparted by TPB in the presence of an alkoxylated amine inhibitor was compared for TPP and TPM, and is shown in Fig. 6. The TPB and TPP are represented by the lower two curves, giving similar dynamic contact angles to each other, which is about 5 degrees lower than the TPM (the upper curve).

The results of Examples 1 to 6 support the following statement: the hydrotrope additive used in the electrolytic plating composition and method of the present invention is advantageous for allowing the bath solution to enter the characteristics of the substrate to be plated. In particular, small features and features with high aspect ratio. In addition, lower static surface tension is beneficial for wafer level plating uniformity.

Example 7

Various experiments were conducted to investigate the effects of TPM, TPP and TPB on Cu deposition impurities. The substrate is a PVD Cu layer. The plating conditions were a wave system of 10 mA/cm 2 × 30 s + 60 mA / cm 2 × 27 s, and a cathode rotation system of 200 rpm (in a 250 ml tank). The impurities were measured by secondary ion mass spectrometry. The results are summarized in Table 1.

These results show that the addition of TPM, TPP and TPB has no significant effect on Cu impurity levels, so acceptable impurity levels are not a problem.

Example 8

Various experiments were conducted to investigate the deposition rate of Cu deposition by TPM, TPP and TPB (using copper sulfate (40 g/L Cu ⁺⁺ ), sulfuric acid (10 g/L), chloride ion (50) ppm, SPS accelerator (63 ppm), Effect of alkoxylated amine inhibitor (200 ppm) and leveling agent (4.2 ppm) plating solution. At 10 g/L TPB, 20 g/L TPP, and 20 g/L TPM concentration in the plating solution, the fill rate was reduced from 15.0 nm/s of the control electrolyte to 12.8, 9.9, and 8.2 nm/s, respectively. (at 10 g/L TPB, 20 g/L TPP, and 20 g/L TPM concentration). At a reduced concentration of 5 g/L, the negative effect on the filling rate was slightly reduced (13.9 nm/s). The roughness (rsd) measurement is a random change. The results are summarized in Table 2.

A cross-sectional photomicrograph of this embodiment of a trench filled by electroplating of several plating solutions is shown in FIG. The trenches are spaced apart from each other by 100 nm and each have an entry dimension of 100 nm and a depth of 200 nm. The photomicrograph on the upper left is taken from the electricity with the above composition. The groove filled with the plating solution. The photomicrograph on the upper right shows the effect of adding TPP to the same solution at a concentration of 20 g/L. The photomicrograph at the bottom left shows the effect of adding TPM to the same solution at a concentration of 20 g/L, and the photomicrograph of the lower right is shown. The effect of adding TPB at a concentration of 10 g/L.

Example 9

The static surface tension of various compositions consisting of a MULA bath containing copper sulfate (40 g/L Cu ⁺⁺ ), sulfuric acid (10 g/L), chloride ion (50 ppm), and glycol ether was measured. One set of four solutions contained tripropylene glycol methyl ether (TPM) at concentrations of 1 g/L, 5 g/L, 10 g/L, and 20 g/L, respectively. The other group contains tripropylene glycol propyl ether (TPP), the third group contains tripropylene glycol n-butyl ether (TPB), and the fourth group contains dipropylene glycol. Dipropylene glycol propyl ether (DPP), fifth containing dipropylene glycol n-butyl ether (DPB), and sixth system containing propylene glycol butyl ether (PB, ie, n-butoxypropanol). The alkylene glycol ether was present in the composition of each group at the same concentration, i.e., 1 g/L, 5 g/L, 10 g/L, and 20 g/L.

The results of the static surface tension measurements are presented in Figure 9 in a bar graph. The dotted line in Fig. 9 indicates that the composition having the surface tension shown in the bar graph has the same copper sulfate, sulfuric acid and chloride ion content. The surface tension of the MULA plating bath, but containing a tetralkoxylated ethylenediamine inhibitor (200 ppm) and no alkylene glycol wetting agent.

Example 10

The MULA formulation was prepared to include copper sulfate (40 g/L Cu ⁺⁺ ), sulfuric acid (10 g/L), chloride ion (50 ppm), and a co-block of alkoxylated amine (200 ppm) and ethylene oxide/propylene oxide. An inhibitor component consisting of a mixture of copolymers (300 ppm). The MULA formulation and four additional formulations (each of which is separately added at a concentration of 1 g/L, 5 g/L, 10 g/L, and 20 g/L of tripropylene glycol propyl ether (TPP)) Dynamic surface tension measurement. A plot of dynamic surface tension versus surface age is shown in FIG.

Example 11

An additional dynamic surface tension test was carried out as described in Example 10, but the alkylene glycol ether component of the formulation was tripropylene glycol butyl ether at a concentration of 1 g/. L, 2.5 g/L, 5 g/L and 10 g/L. A plot of dynamic surface tension versus surface age is shown in Figure 11.

Example 12

Additional dynamic surface tension tests were carried out as described in Example 10, but only three formulations contained alkylene glycol ethers. (alkylene glycol ether), and the alkylene glycol ether component is propylene glycol butyl ether (PB) at concentrations of 1 g/L, 5 g/L and 10 g/L, respectively. A graph of dynamic surface tension versus surface age is shown in Figure 12. The data shown in Figure 13 is from the baseline MULA solution of Examples 10 to 12, which were separately added with 2.5 g/L of tripropylene glycol n-butyl ether (TPB), added. 5g/L propylene glycol n-butyl ether (PB, ie, n-butoxypropanol), and 10g/L tripropylene glycol propyl ether (TPP). Figure 13 shows a curve of TPB of 2.5 g/L, PB of 5 g/L, and TPP of 10 g/L, which are almost identical. Similarly, Figure 14 is a graphical representation of the MULA baseline solution from Examples 10 through 12, which were added with 5 g/L TPB, 10 g/L PB, and 20 g/L TPP, respectively. Further, it was found that the curves of several formulations containing alkylene glycol were substantially identical. The data from Examples 10 through 12, surface ages of 0.1 seconds, 1 second, and 10 seconds, are summarized in Table 3 below.

Example 13

Perform a static surface tension test for a baseline MULA formulation consisting of copper sulfate (40 g/L Cu ⁺⁺ ), sulfuric acid (10 g/L), and chloride ion (50 ppm), and for separate Four different hydrotrope MULA solutions were added. One solution contains TPB, and the other contains ethoxylated TPB prepared by the reaction of a molar TPB with 0.5 mole of ethylene oxide, and the third contains ethoxylated TPB by a molar TPB and 1.0. The reaction preparation of moth ethylene oxide, and the fourth one contains ethoxylated TPB which is prepared by the reaction of TPB with 1.5 mol of ethylene oxide. The static surface tension measurement results are shown in Figure 15 as a long bar. The dotted line in Fig. 15 indicates that the composition having the surface tension shown in the bar graph has the same copper sulfate, sulfuric acid and chloride ion content, but it contains an alkoxylated amine inhibitor (200 ppm) and does not contain an alkylene glycol wetting agent. The surface tension of the baseline MULA plating bath.

Based on the same data, Figure 16 is a graph showing the static surface tension versus humectant concentration for TPB and ethoxylated TPB (at TPB: 0.5 EO, TPB: 1.0 EO and TPB: 1.5 EO). As shown in Figure 17, the chronopotential experiments of the solutions used in this example produced nearly identical polarization curves for the benchmark formulations and formulations containing TPB: 0.5 EO, TPB: 1.0 EO and TPB: 1.5 EO.

Example 14

A dynamic surface tension test was performed on a solution containing TPB: 1.5 EO in a MULA solution containing copper sulfate (40 g/L Cu ⁺⁺ ), sulfuric acid (10 g/L), and chloride ion (50 ppm). The test was carried out on individual solutions containing TPB: 1.5 EO at concentrations of 2.5 g/L, 5 g/L, 10 g/L, 15 g/L and 20 g/L, respectively. A graph of dynamic surface tension versus surface age is shown in FIG.

Example 15

The low copper makeup solution was prepared from copper sulfate (5 g/L Cu ⁺⁺ ), sulfuric acid (10 g/L), and chloride ion (50 ppm). The plating solution was prepared by adding SPS (63 mg/L), an inhibitor (200 ppm), and a wetting agent, which comprises a propylene oxide and ethylene oxide repeating unit containing an equivalent molar ratio. The polyalkylene oxide alkane oxidized butanol has a molecular weight of 270, mainly HO-(EO) ₂ (PO) ₂ Bu. A chronopotentiometry test performed on both a low copper solution and a low copper solution with a wetter showed a 10 mv increase in polarization strength in the presence of a wetter, as shown in Figure 19 ( Copy polarization curve shown). The adsorption time is also faster than that of the non-humectant solution, and the failure rate of the two solutions (the slope of the potential curve after reaching the maximum voltage) is similar.

Example 16

Two compositions containing the alkoxylated butanol (7.5 g/L) as described in Example 15 were prepared. One solution was added with an alkoxylated amine inhibitor at a concentration of 200 ppm. Each of these solutions was subjected to a dynamic surface tension test. The results are shown in Figure 20.

Example 17

A solution containing the alkoxylated butanol of Example 15 in a low copper electrolyte solution containing copper sulfate (5 g/L Cu ⁺⁺ ), sulfuric acid (10 g/L), and chloride ion (50 ppm) was subjected to a dynamic surface tension test. Individual solutions containing alkoxylated butanol at concentrations of 2.5 g/L, 5 g/L, 10 g/L, 15 g/L, 20 g/L, 30 g/L, and 50 g/L, respectively, were tested. A plot of dynamic surface tension versus time is shown in Figure 21.

Example 18

Experiments were conducted to compare TPB with modified hydrotropes (prepared by reacting TPB with 0.5, 1.0, and 1.5 moles of ethylene oxide, respectively) with copper sulfate (5 g/L Cu ⁺⁺ ), Solubility in a low copper MULA bath of sulfuric acid (10 g/L) and chloride ion (50 ppm). When a mixture of 10 g/L TPB and a low copper electrolyte was stirred at 750 rpm at room temperature, it took more than 60 minutes to fully dissolve the TPB. When the electrolyte and a mixture of 10 g/L of the reaction product of TPB and ethylene oxide were stirred under the same conditions, the TPB:0.5 EO product was completely dissolved in 4 minutes, and each TPB: 1.0 EO and TPB: 1.5 EO product Fully dissolved in 2 minutes.

Cloud point measurements were made on formulations containing different concentrations of TPB and formulations containing different amounts of TPB and 1.5 moles of ethylene oxide. The observed cloud point is summarized in Table 4:

A foam height test was performed on an electrolytic plating solution containing a low copper electrolyte and an alkoxylated amine inhibitor. The comparative foaming height measurement was carried out for the same plating solution in which 7.5 g/L and 10 g/L of the reaction product of TPB and 1.5 mol of ethylene oxide were separately added. The results of these tests are shown in Table 5.

Example 19

Dynamic surface tension tests were performed on eight different solutions: (1) low acid MULA containing alkoxylated amine inhibitor (200 ppm); (2) low copper electrolyte containing alkoxylated amine inhibitor (200 ppm); (3) MULA, An inhibitor comprising a mixture comprising an alkoxylated amine (200 ppm) and an EO/PO co-block polymer (300 ppm); (4) a low copper electrolyte containing the same inhibitor mixture as Solution 3; (5) a low acid MULA, Contains the same alkoxide amine inhibitor mixture as in solution 3, with different EO/PO coblock polymers (300 ppm); (6) low copper electrolyte containing the same inhibitor mixture as solution 5; (7) low Acid MULA containing TPP (20 g/L); and (8) low acid MULA containing an alkoxylated amine inhibitor (200 ppm) and TPP (20g/L).

Figure 22 is a graph showing the dynamic surface tension of each formulation of this example versus surface age. The dynamic surface tension curve for solution 8 (both inhibitor and TPP in low acid MULA) can be seen to be consistent with the curve for solution 7 (containing only TPP in low acid MULA). Each of the solutions 7 and 8 exhibited a much lower dynamic surface tension than any other solution.

The present invention has been described in detail, and it is possible to understand modifications and variations of the scope of the invention as defined by the appended claims.

When introducing elements of the present invention or its preferred embodiments, the articles "a", "an", "the" and "said" are intended to mean one or more. Multiple components. The terms "including", "comprising" and "having" are intended to include the recited elements and the meaning

In view of the above, it will be appreciated that a number of objects of the present invention have been achieved and other advantageous results.

Since the various changes in the above-described compositions and methods can be made without departing from the scope of the invention, it is intended to be construed as illustrative and not limiting. concept.

Claims (33)

An aqueous composition for electroplating copper comprising a source of copper ions and one or more alkylene glycol ethers or polyalkylene glycol ethers having the following general structure (1) or (2) ( Polyalkylene glycol ether): R ¹ O[CH ₂ CHR ² O] _n R ³ structure (1) R ¹ O[CH ₂ CHR ² O] _n [CH ₂ CHR ⁴ O] _m R ³ structure (2) wherein R ¹ is a substituted or unsubstituted alkyl, cycloalkyl or aryl group having 1 to 6 carbon atoms; R ² is H or a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms R ⁴ is H or a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms, and R ⁴ is different from R ² ; R ³ is H or -CH ₂ CH(OH)CH ₂ -OH, and The n and m systems are such that the alkylene glycol ether or polyalkylene glycol ether is soluble in the aqueous phase and has a molecular weight of no greater than about 500. The aqueous composition of claim 1, wherein R ² is a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms. An aqueous composition according to claim 2, wherein R ⁴ is H. The aqueous composition of claim 1, wherein n is an integer of 1 to 5, m is an integer of 1 to 3, and m+n is an integer of 1 to 6. The aqueous composition of claim 4, wherein n is an integer of 1 to 4 or 2 to 4. The aqueous composition of claim 5, wherein n is An integer from 1 to 4, m is an integer from 1 to 2, and m+n is an integer from 3 to 5. The aqueous composition of claim 1, wherein the sum of the concentrations of the alkylene glycol ether or the polyalkylene glycol ether is between about 1 and about 20 g/L. Between, or between about 3 and about 20 g/L or between about 5 and about 20 g/L, or between about 5 and about 15 g/L, or between about 5 and about 10 g/ Between L. The aqueous composition of claim 1, wherein R ¹ is selected from the group consisting of substituted and unsubstituted alkyl groups and substituted and unsubstituted cycloalkyl groups. The aqueous composition of claim 8, wherein the R ^{1 group} comprises a substituted or unsubstituted alkyl group. The aqueous composition of claim 1, wherein the glycol ether corresponds to the general structure (1), wherein R ¹ is a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms; ² is a methyl group; R ⁴ is hydrogen; and n is an integer between 1 and 3, inclusive. The aqueous composition of claim 2, which comprises a mixture of a plurality of structures (2), or a mixture of structures (1) and (2), wherein R ⁴ is H and n is 2 or 3 And the average m-value m* in the mixture is between about 0.2 and about 0.8, or between about 0.8 and about 1.2, or between about 1.2 and about 1.8. The aqueous composition of claim 11, wherein R ² is a methyl group, and R ¹ is a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms. The aqueous composition of claim 1, which further comprises an inhibitor compound. The aqueous composition of claim 13, wherein the inhibitor is present in a concentration effective to promote submicron interconnect features of the superfilling semiconductor integrated circuit device substrate. The aqueous composition of claim 13, wherein the inhibitor comprises a polyether bonded to a nitrogen-containing type of nitrogen, the polyether comprising propylene oxide (PO) The coating unit and the ethylene oxide (EO) repeating unit have a PO:EO ratio of between about 1:9 and about 9:1, and the inhibitor has between 1000 and 30,000. The molecular weight between. The aqueous composition of claim 15 wherein the repeating unit PO:EO ratio is between about 1.5 and 8:5, or between 2:8 and about 8:2, or Between about 3:7 and about 7:3. The aqueous composition of claim 13, wherein the inhibitor has a concentration in the electrolytic plating solution of between about 40 and about 250 mg/L. The aqueous composition of claim 13, wherein the inhibitor is present in the electrolytic plating solution at a concentration of between about 10 and about 400 mg/L. The aqueous composition according to any one of claims 1 to 18, wherein the composition has a dynamic surface tension at 25 ° C of not more than about 55 dynes/cm, and a static surface tension at 25 ° C is not It is greater than about 50 dynes/cm, and the cloud point is at least 30 ° C, preferably at least 50 ° C. The aqueous composition of claim 19, which has a static surface tension at 25 ° C of not more than 45 dynes/cm, usually from about 35 to about 45 dynes/cm. The aqueous composition of claim 20 has a dynamic surface tension of no greater than about 45 dynes/cm, typically between about 35 and about 45 dynes/cm. A method of electrodepositing copper on a substrate comprising a copper-based or cobalt-based surface, the method comprising: providing an electrolytic circuit comprising a power source, an anode in contact with the electrodeposition solution, and containing the a cathode on the surface of the substrate and in contact with the electrodeposition solution; and an electrolysis current is passed through the circuit to deposit copper on the cathode; the electrodeposition solution having the composition according to any one of claims 1 to 21. The method of claim 22, wherein the substrate surface comprises a copper-based or cobalt-based seed layer on a support structure selected from the group consisting of: Sub-micron-characterized semiconductors, through silicon vias, and printed circuit boards that are to be filled with electrodeposited copper. The method of claim 23, wherein the layer comprises Cu or Co. The method of claim 23 or 24 includes the method of damascene plating in a submicron interconnect of a semiconductor device. The method of claim 25, wherein the substrate comprises sub-micron size interconnect features having an aspect ratio of at least about 3:1 or at least about 4:1, or at least about 5: 1, or at least about 8:1. The method of claim 26, wherein the substrate comprises sub-micron features having the following combination: an aspect ratio is 4:1 5:1 or 8:1, and the inlet size is less than about 100 nm, less than 50 nm, less than 30 nm, less than 20 nm, or less than 10 nm. The method of claim 26, wherein the substrate comprises sub-micron features having an entrance size of between about 20 and about 50 nm, or between about 10 and about 30 nm, or between about 5 and between about 10 nm. An aqueous composition for electroplating copper, comprising a source of copper ions and one or more alkylene glycol monoethers or polyalkylene glycols having the following general structure (8) Monoether): R ¹ O[CH ₂ CR ⁴ O] _m [CH ₂ CHR ² O] _n [CH ₂ CH ₂ O] _p R ³ structure (8) wherein R ¹ is substituted or unsubstituted and has 1 An alkyl group, a cycloalkyl group, or an aryl group to 6 carbon atoms; R ² is a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms; R ⁴ is H or has 1 to 3 carbon atoms a substituted or unsubstituted alkyl group, R ⁴ is different from R ² , R ³ is H or CH ₂ CH(OH)CH ₂ -OH, and n, m and p are alkylene glycol ethers ( The alkylene glycol ether) or polyalkylene glycol ether is soluble in the aqueous phase and has a molecular weight of no greater than about 500. The aqueous composition of claim 29, wherein R ⁴ is H. The aqueous composition of claim 29, which comprises a mixture of the types of structures (4), wherein the m-value average m*, the n-value average n*, and the p-value average p* are the number of mixtures The average molecular weight is less than 500. The aqueous composition of claim 31, wherein the p* is between 0.5 and 2.0 or between 1.0 and 2.0. An aqueous composition according to claim 31, wherein the p* is between 0.2 and 0.8, or between 0.8 and 1.2, or between 1.2 and 2.0.