JP2001102328A - Method for manufacturing semiconductor integrated circuit device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve embedding characteristics of a metal plating film into a fine wiring groove or through-hole. SOLUTION: For embedding of a metal film into a wiring groove or through- hole by utilizing a metal precipitation through electroplating, a plating solution is used which is doped with a substance having, such a chemical structure that a part of a molecular structure has a tertiary amine and a linear conjugation system with positive charges or an aromatic cycle conjugation system with positive charges, which consists of four or more atomic chains and that at least one bond of nitrogen in the tertiary amine has directly bonded with the conjugation system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technology for manufacturing a semiconductor integrated circuit device, and more particularly to a technology effective when applied to the formation of a buried metal wiring using a plating method.

[0002]

2. Description of the Related Art In recent years, with the miniaturization of Al (aluminum) wiring due to the high integration of LSIs, the resistance of wiring and the decrease in reliability have become remarkable, and especially high performance logic L
In the SI, this is a major obstacle to higher speed and higher performance. Therefore, recently, a wiring groove (and a through hole) is formed in an insulating film deposited on a silicon substrate, and then a Cu having lower electric resistance than the Al film is formed on the insulating film including the inside of the wiring groove (and the through hole). After depositing the film, an unnecessary Cu film outside the wiring groove is subjected to chemical mechanical polishing (CM).
P) method, so-called damascene (Damascen)
e) Introduction of buried Cu wiring using the method has been promoted. This technology is described in, for example, Japanese Patent Application Laid-Open No. 2-27.
No. 8822 and Japanese Patent Application Laid-Open No. H10-213434.

[0003]

In the step of forming a buried Cu wiring using a damascene method, a method of depositing a Cu film on an insulating film including the inside of a wiring groove (and a through hole) is performed in advance by using a Cu seed. A plating method is used in which the wafer on which the layer is formed is immersed in a plating solution composed of a sulfuric acid acidic copper sulfate aqueous solution, and a Cu film is deposited on the surface of the seed layer connected to the anode electrode.

However, since the plating solution used in the plating method is based on the plating solution used in the manufacturing process of a printed wiring board, extremely fine wiring grooves and through holes formed on a wafer are formed. No sufficient consideration has been given to the characteristics of embedding the film in the inside of the substrate. That is, in order to completely bury the Cu film in such fine wiring grooves and through holes, anisotropic growth in which the film grows preferentially from the bottom of the wiring grooves (through holes) is required. With the above plating solution, the growth of the film from the bottom of the wiring groove (through hole) is only slightly faster than the growth from the side wall. Therefore, the design rule of the LSI becomes 0.13 μm to 0.14 μm or less,
Accordingly, the width of the wiring groove and the diameter of the through hole are reduced to about 250.
When the thickness is less than nm, it is difficult to completely bury the Cu film in the inside thereof, and voids (voids) are generated.

An object of the present invention is to provide a technique for improving the burying characteristics of a metal film in a fine wiring groove or a through hole when forming a buried metal wiring by using a plating method.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0007]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows.

In a method of manufacturing a semiconductor integrated circuit device according to the present invention, after forming a wiring groove or a through hole in an insulating film on a main surface of a semiconductor substrate, an upper surface of the insulating film and an inner wall of the wiring groove or the through hole are formed. Forming a first metal film covering the first metal film, and depositing a second metal film on the surface of the first metal film using a metal deposition reaction by electroplating, so that the inside of the wiring groove or through hole is formed. A step of embedding the second metal film, a tertiary amine having a part of a molecular structure and a linear conjugate system having four or more atomic chains and having a positive charge or an aromatic ring conjugate having a positive charge. And a plating solution to which a substance having a chemical structure in which at least one bond of nitrogen in the tertiary amine is directly bonded to the conjugated system is added. Deposit the second metal film on the surface It is intended to be.

According to the above means, the tertiary amine in the substance having the chemical structure binds to and covers the surface of the first metal film, so that the deposition of the second metal film is inhibited. You. However, the substance is not easily bonded to the surface of the first metal film due to a conjugated steric hindrance effect at the bottom of the fine wiring groove or through hole. That is,
The plating reaction is inhibited near the top surface of the insulating film and near the opening of the wiring groove or through hole, whereas the plating reaction is not inhibited near the bottom of the wiring groove or through hole. The second metal film is preferentially buried from the bottom of the hole.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. In all the drawings for describing the embodiments, the same members are denoted by the same reference numerals, and a repeated description thereof will be omitted.

A CMOS-LS according to an embodiment of the present invention
The manufacturing method of I will be described according to the steps.

First, as shown in FIG.
According to the process, an element isolation groove 2 is formed in a semiconductor substrate (hereinafter, referred to as a substrate or wafer) 1 made of single crystal silicon.
After forming the p-type well 3 and the n-type well 4, an n-channel MISFET Qn is formed in the p-type well 3, and a p-channel MISFET Qp is formed in the n-type well 4.
The n-channel MISFET Qn mainly includes a gate oxide film 5, a gate electrode 6 composed of, for example, a polycrystalline silicon film, a WN (tungsten nitride) film and a W (tungsten) film, and an n-type semiconductor region (source, drain) 7. Consists of Also, a p-channel type MISFET Q
p mainly includes a gate oxide film 5, a gate electrode 6, and an n-type semiconductor region (source and drain).

Next, after the surface of the silicon oxide film 9 deposited on the substrate 1 by the CVD method is flattened by a chemical mechanical polishing (CMP) method, the silicon oxide film 9 is dry-etched to thereby form an n-type semiconductor region. A contact hole 10 is formed above the (source, drain) 7, and a contact hole 11 is formed above the p-type semiconductor region (source, drain) 8.

Next, first-layer wirings 12 to 17 are formed on the silicon oxide film 9. First layer wirings 12-1
7, a TiN film and a W film are formed in the contact holes 10 and 11 and on the silicon oxide film 9 by CVD.
After depositing the films, these films are formed by dry etching.

Next, as shown in FIG. 2, a silicon nitride film 18 having a thickness of about 100 nm, a silicon oxide film 19 having a thickness of about 400 nm,
A silicon nitride film 20 having a thickness of about 00 nm and a silicon oxide film 21 having a thickness of about 400 nm are sequentially deposited. The silicon nitride films 18 and 20 are deposited by, for example, a plasma CVD method, and the silicon oxide films 19 and 21 are deposited by, for example, a plasma CVD method using ozone and tetraethoxysilane (TEOS) as a source gas.

Next, as shown in FIG. 3, dry etching is performed using a photoresist film 22 formed on the silicon oxide film 21 as a mask to form one of the silicon oxide film 21, the silicon nitride film 20, and the silicon oxide film 19. Then, through holes 23 to 26 are formed in the portions. Through hole 23-2
The diameter of 6 is, for example, 250 nm or less.

Next, after removing the photoresist film 22, a coating type anti-reflection film 27 is formed inside the through holes 23 to 26 and on the silicon oxide film 21, as shown in FIG. As shown in FIG.
7 is used as a mask to dry-etch the antireflection film 27 and the silicon oxide film 21 to form a wiring groove 30 above the through hole 23, and to form a wiring groove 30 above the through holes 24 and 25. The wiring groove 31 is formed in the
Form 2 This etching is performed on the silicon nitride film 2
The silicon oxide film 19 at the bottoms of the through holes 23 to 26 is simultaneously etched using 0 and 18 as stoppers.

Next, as shown in FIG. 6, by dry etching using the photoresist film 28 as a mask, the silicon nitride film 20 at the bottom of the wiring grooves 30 to 32 and the silicon nitride film 18 at the bottom of the through holes 23 to 26 are formed. And remove.

Next, after removing the photoresist film 28 and the antireflection film 27 remaining under the photoresist film 28, as shown in FIG. 7, the upper portion of the silicon oxide film 21 and the wiring grooves 30 to 32 and the through holes 23 to 26 are formed. Inside, for example, Ta
A barrier film 33 made of (tantalum) is formed. This barrier film 33 is formed to prevent the Cu film formed in the next step from diffusing into the silicon oxide film 21 and to improve the adhesion between the Cu film and the silicon oxide film 21.
Since the barrier film 33 must also cover the bottoms of the through holes 23 to 26 formed below the wiring grooves 30 to 32, the barrier film 33 is deposited by a long throw sputtering method with a distance of 200 mm from the substrate 1. The thickness of the barrier film 33 is, for example, about 50 nm above the silicon oxide
20nm near the center of ~ 32, through holes 23 ~ 26
It is about 6 nm on the side wall. The barrier film 33 includes TiN
(Titanium nitride), TaN (tantalum nitride), or the like can also be used.

Next, as shown in FIG. 8, the upper portion of the silicon oxide film 21 and the wiring grooves 30 to 32 and the through holes 23 are formed.
26, a Cu seed film (first metal film) 34 is formed. Since the seed film 34 must cover the bottoms of the through holes 23 to 26 formed below the wiring grooves 30 to 32, the seed film 34 is deposited by a long throw sputtering method at a distance of 200 mm from the substrate 1. The thickness of the seed film 34 is, for example, about 100 nm above the silicon oxide film 21 and about 4 nm inside the wiring grooves 30 to 32 and the through holes 23 to 26.

Next, a Cu film (second metal film) 35 is deposited on the surface of the seed film 34 by the following method.

FIG. 9 is a schematic structural view of a plating apparatus 50 used for forming a Cu film. A plating solution 53 is stored in the plating tank 51 and the plating solution storage tank 52. The wafer 1 is fixed to a bottom surface of a wafer holder 56 while being held by holder pins 55 connected to a negative electrode of a power supply 54. An anode 57 made of Cu connected to a positive electrode of a power supply 54 is provided in a plating tank 51 below the wafer holder 56.
Are provided facing the wafer 1. The anode 57 has a plurality of holes 58 through which the plating solution 53 passes. The plating solution 53 is supplied from the plating solution storage tank 52 to the pump 59 and the filter 6 as indicated by arrows in the drawing.
The liquid is sent to the plating tank 51 through 0 and returned to the plating liquid storage tank 52 again through the pipe 61. To apply plating to the surface of the wafer 1 held by the holder pins 55, a plating solution 5
While circulating 3 through the above-described path, a predetermined current is continuously supplied to the wafer 1 for a certain period of time.

[0023] Although not particularly limited, the plating solution 53 in the present embodiment is composed mainly of copper sulfate aqueous solution of sulfuric acid acidity, for example, copper sulfate _{(CuSO 4 · 5H 2 O)} 5
It contains 0 g / l and sulfuric acid (H ₂ SO ₄ ) at a concentration of 100 ml / l. The plating solution 53 contains, for example, 50 pp of chlorine ions (Cl ⁻ ) as an additive for improving the flatness of the Cu plating film.
and 0.1 g / liter of thiourea (SC (NH ₂ ) ₂ ). Further, as an additive for improving the wettability between the plating solution 53 and the seed film 34, for example, several pp
It contains polyvinyl alcohol (PVA) at a concentration of about m.

The plating solution 53 of the present embodiment contains, in addition to the above-mentioned additives, a substance having a specific chemical structure having a plating inhibiting function as an additive for improving the filling characteristics of the Cu plating film. I have. The “specific chemical structure” is specifically defined as “a tertiary amine and a conjugated linear conjugate system having four or more atomic chains, A structure in which at least one bond of nitrogen in the tertiary amine is directly bonded to the conjugated system. Hereinafter, the substance having the plating inhibiting function will be described in detail.

The substance having the plating inhibiting function is adsorbed on the metal (Cu) surface at the negative electrode at the time of plating treatment, and covers the metal surface so that metal ions reach the metal surface and become zero-valent metal atoms. It is a surface adsorption type plating inhibitor that inhibits reduction. Therefore, the plating inhibitor must have a functional group capable of coordinating with a metal in the molecule. The functional group forms a conjugate bond with carbon (element symbol C) forming a molecular skeleton,
And it is necessary to be electrochemically stable. This functional group must not be negatively charged for the reasons further described below. From the above requirements, amine is selected as the functional group.

Further, the plating inhibitor needs to have a function of inhibiting a plating reaction by coating a metal surface. This is achieved by the presence of a large molecular weight group next to the amine, which means that it has a "linear or conjugated aromatic ring system of four or more atomic chains" as described above. . That is,
Nitrogen in the amine (hereinafter abbreviated as amine nitrogen) is adsorbed on the metal surface, and the metal surface is coated with a conjugated system having a large molecular weight bound to the amine nitrogen. From the viewpoint of the shielding function, a group whose steric structure easily changes even if its molecular weight is large, such as a saturated alkyl group, cannot stably cover the metal surface, and is unsuitable. That is, a conjugated system having a stable three-dimensional structure and capable of efficiently covering a wide area is suitable. For example, C = C having two carbon atoms and one double bond is unsuitable because it has only the same size as the atomic radius of the metal, and C = C having at least four carbon atoms and two double bonds. The structure of -C = C is essential. The conjugated structure of C ＝ C−C ＝ C has no problem not only when it forms part of a linear chain but also when it forms part of a conjugated aromatic ring.

In the above plating inhibitor, the amine nitrogen in the molecule is strongly coordinated to the metal surface. In particular, fine wiring grooves 3
0 to 32 and the inside of the through holes 23 to 26, the ratio of the area of the side wall to the amount of the plating solution 53 becomes large.
The surface-adsorbing substance is quickly removed from the plating solution 53. As a result, the plating inhibitor cannot reach a certain depth or more inside the fine wiring groove / through hole, and a metal plating film is preferentially formed at a position deeper than that. Further, by continuing the plating process, the side wall of the wiring groove / through hole is covered with the plating inhibitor to inhibit the growth of plating, while the bottom of the wiring groove / through hole is not covered with the plating inhibitor. A metal plating film grows at a stretch from the metal surface, and the inside of the wiring groove / through hole is buried from the bottom.

The above-mentioned plating inhibitor has a skeleton of N-C = C-C = C when amine nitrogen is included, and has a size that cannot be ignored with respect to the irregularities on the atomic scale of the metal surface. Therefore, there is another anisotropic embedding mechanism derived from this molecular structure. In other words, at the bottom of the wiring groove / through hole whose surface is essentially concave, the skeleton of N-C = C-C = C hinders the metal surface from being covered efficiently, Since there are no irregularities on the outside or the side wall of the groove / through hole, the plating inhibition effect is more easily exhibited as compared with the bottom (the concave shape of the bottom of the wiring groove / through hole will be described in more detail later). As a result, the metal plating film grows preferentially at the bottom of the wiring groove / through hole where the plating inhibition effect is weak, and also has a characteristic that the inside of the wiring groove / through hole is buried.

However, since the simple conjugate system is hydrophobic, there is a problem that the water solubility of the additive is impaired.
In order to solve this problem, “a linear conjugate system having a positive charge or an aromatic ring conjugate system having a positive charge” is selected. That is, the conjugated system itself is easily charged in water, which is a polar solvent, by being charged. In experiments, at least 1
Since it was difficult to obtain a sufficient effect unless the solubility was at least ppm, a numerical value of at least 1 ppm is given as a measure of the water solubility of the plating inhibitor. It is also possible to impart a certain degree of water solubility to the plating inhibitor by modifying the conjugated system with a charged functional group instead of the conjugated system itself being charged. However, in this case, a large modifying group will be attached to the side surface of the conjugated system, which is not suitable because it becomes an obstacle when the conjugated system approaches the metal surface and reduces the shielding effect. It is important that the conjugate system itself is charged.

Here, it is essential that the electric charge of the conjugated system is a positive electric charge. This is because the object to which the plating inhibitor is adsorbed is the negative electrode surface, and if the plating inhibitor has a negative charge, it becomes difficult to approach the negative electrode surface due to electrostatic repulsion. The same is true with respect to functional groups coordinated to the above-mentioned metal surfaces, e.g. COO ^- in negative charge tinged functional groups such as not suitable even if having a coordination bond.
That is, the above functional group must be electrically neutral or positively charged. Furthermore, the fact that the plating inhibitor has a positive charge also functions advantageously for the embedding property of the plating film. That is, the positively charged additive molecules are electrostatically attracted to the surface of the negative electrode metal during the plating process and are restrained in the vicinity of the surface. Therefore, the plating inhibitor is constrained by the metal surface around the opening of the wiring groove / through hole, and most of the plating inhibitor cannot diffuse into the wiring groove / through hole. That is,
Since the plating inhibitor does not reach the surface of the metal plating film growing from the bottom of the wiring groove / through hole and the film growth is not suppressed, the inside of the wiring groove / through hole is filled with the metal plating film. .

As is well known, a primary amine R—NH ₂ (R: alkyl group or the like) having one organic group bonded thereto and a secondary amine R ₁ R ₂ − having two organic groups bonded thereto are known. N
H (R _{1 ,} R ₂ : an alkyl group, etc.) and a tertiary amine R ₁ R ₂ R ₃ —N (R _1, R _2, R ₃ :
Alkyl group). Generally, an alkyl group is an electron donating group, and the more alkyl groups bonded to an amine nitrogen, the more electrons are donated from the alkyl group, and the basicity tends to be stronger. Since the present invention aims at increasing the electron density of amine nitrogen and increasing the coordination bonding force with the metal surface, amines are limited to tertiary amines.

However, mere tertiary amine is strongly basic, so that it easily becomes an ammonium ion (R ₁ R ₂ R ₃ —NH ⁺ ) in an ordinary plating solution which is strongly acidic, and has a coordination bond. I will lose. Therefore, a chemical structure in which the basicity is weakened while the electron density of amine nitrogen is high is required. The conjugate system next to the amine nitrogen has not only a plating inhibiting function but also an effect of weakening the basicity of this nitrogen. That is, FIG.
As shown in FIG. 0, since the influence of the conjugated system extends to the amine nitrogen having a lone electron pair, a higher energy is required to form an ammonium ion by overcoming the influence than a simple amine. As a result, the chemical equilibrium between the amine and the ammonium ion can be further advanced to the amine side than usual. As described above, the amine in the plating inhibitor is limited to an amine having a specific structure in which the electron density of amine nitrogen is increased to enhance the coordination bond property, but the basicity is not so strong.

As plating inhibitors having the above characteristics,
For example, Basic Blue shown in FIG.
3. Diazine Black shown in Fig. 12
, Methyl Violet shown in FIG.
2B, Methylene Blu shown in FIG.
e) and the like.

In general, the carbon of an alkyl group is bonded to the amine nitrogen. However, in the plating inhibitor of the present invention, as in the case of the alkyl group, other carbon atoms are effective to increase the electron density of the amine nitrogen. A nitrogen atom may be attached to the amine nitrogen. As an example of such a plating inhibitor, for example, tetranitro blue tetrazonium
Chloride (Tetranitro Blue Tetrazolium Chloride),
2,3,5-triphenyl- shown in FIG.
2H-Tetrazolium Chlor
ide).

The plating current of the plating solution 53 to which the plating inhibitor of the present invention is added is necessarily smaller than the plating current of the plating solution containing no plating inhibitor. this is,
According to the principle that the plating current is proportional to the total amount of metal deposited on the negative electrode surface by the plating reaction, the inhibition of plating is reviewed from the viewpoint of plating current.
FIG. 17 shows the results of measuring the relationship between plating voltage and current by changing the concentration of the additive added to the plating solution. It can be seen that as the concentration of the additive increases, the current (that is, the plating current) when the same voltage is applied decreases. In the present embodiment, the plating is performed at a constant current (1 A / dm ² ).
In this case, a higher voltage is required as the concentration of the additive increases.

The above-mentioned plating inhibitor is adsorbed on the metal surface by coordinating the amine nitrogen with the metal, while the conjugate system adjacent to the nitrogen atom becomes positively charged and is electrostatically attracted to the negative electrode metal surface. Therefore, it is possible to effectively cover the metal surface and inhibit the plating reaction. For this purpose, it is desirable that the amine nitrogen and the conjugated system have a three-dimensional positional relationship such that they can simultaneously approach the negative electrode metal surface.

However, if the bond between the amine nitrogen and the conjugated system has a rotational degree of freedom, the above positional relationship is not guaranteed, and the amine nitrogen is adsorbed on the metal surface as shown in FIG. Even if it does, the conjugate system may have a positional relationship so as not to approach the metal surface. Therefore, a structure in which the amine nitrogen is part of a five-membered or six-membered ring composed of nitrogen and carbon and contains at least a part of atoms constituting a conjugated system in the five-membered ring or the six-membered ring. As a result, a positional relationship as shown in FIG. 18B where the amine nitrogen and the conjugated system can simultaneously approach the negative electrode metal surface is guaranteed. In this method, the degree of freedom of rotation is removed from the bond between the amine nitrogen and the conjugate system, and the amine nitrogen and the conjugate system are fixed in a positional relationship close to the same plane. In this structure,
When the nitrogen atom is adsorbed on the metal surface by the coordination bond, the conjugate system also approaches the metal surface at the same time.

As an example of a plating inhibitor having such characteristics, Basic Red shown in FIG.
12, Strain-all shown in FIG. 20,
Cyanine dyes shown in FIGS. 21 and 22 can be mentioned. In strain all (FIG. 20) and cyanine dyes (FIGS. 21 and 22), the anion is Br ⁻ or I ⁻ . However, even if the anion is not Cl ⁻ , the function of the plating inhibitor is not particularly affected. . The remaining one carbon bonded to the amine nitrogen is the carbon of the alkyl group, and the steric hindrance due to this alkyl group cannot be removed even by the above five-membered or six-membered ring structure. Figure 2 shows the reason
3 will be described.

FIG. 23B shows the bond between the amine nitrogen and the remaining one carbon as viewed from the direction of the arrow shown in FIG. The rotational freedom of the C-C bond, but an alkyl group attached to the carbon which may come to the position of R _1, R _2, R _3, when the alkyl group has come to the position of R _2, just nitrogen And the conjugate group both cause steric hindrance when approaching the metal surface. In other words, the carbon atom at the β-position (position next to the nitrogen) is a steric hindrance between the additive molecule and the metal surface depending on the configuration, and the carbon atom remains on the metal surface until the nitrogen atom forms a coordination bond. The possibility of inaccessibility arises. Of course, it is also possible to adopt a structure in which the carbon atom at the β-position does not hinder the coordination bond due to the rotation of the CC bond (R ₁ is the position that does not cause the most steric hindrance, and R ₃ is next to it). Therefore, this obstruction effect is not absolute, but causes a great difference in plating inhibition effect when comparing materials having similar structures. As a method of eliminating the influence of the β-position carbon atom, it is effective to limit the remaining one group bonded to the nitrogen atom to an alkyl group having no β-position carbon, that is, a methyl group CH ₃ —.
In the above-mentioned cyanine dyes, a structure in which an ethyl group is substituted with a methyl group (FIGS. 24 and 25) or Basic Red 1
2 (FIG. 19) corresponds to this.

The above "having a tertiary amine as a part of the molecular structure and having a linear conjugate system having a positive charge or an aromatic ring conjugate system having a positive charge, comprising four or more atomic chains. A structure in which at least one bond of nitrogen in the tertiary amine is directly bonded to the conjugated system ”, by setting the length of the conjugated system to 1 nm or more, the effect of the plating inhibitor is reduced. Can be higher.

The length of the conjugated system as referred to herein is the length of the skeleton formed by atoms other than hydrogen. A feature of the plating inhibitor molecule is that it is much larger than the size of the crystal lattice of the metal formed by plating. FIG.
(111) plane and the plating inhibitor molecules adsorbed on the (111) plane. Here, attention is paid to the step of the atomic size existing on the metal surface and the steric hindrance effect of the plating inhibitor molecules adsorbed. When the size of the inhibitor molecules is more than three Cu atoms on the crystal lattice, The effect becomes remarkable. As can be seen from FIG. 26, this is approximately equivalent to four benzene rings and 1 nm in length.

Examples of specific plating inhibitors to which the above conditions apply are the cyanine dyes (FIGS. 21 and 2).
2) and strain all (FIG. 20). It is assumed that the plating inhibitor having this structure is adsorbed on a metal surface that is concave in atomic size. Wiring grooves 30 to 32 or diameter 2 having a width of 250 nm or less to be embedded according to the present invention.
Excluding the thicknesses of the barrier film 33 and the seed film 34 formed before embedding, the through-holes of 50 nm or less have a maximum width of 230 nm (wiring groove) or a diameter of 230 nm (through-hole). When embedding a metal plating film in these recesses, first, a metal film is preferentially formed at the bottom corner of the wiring groove / through hole by the above mechanism, and the corner is rounded. Ideally, a curved surface with a radius of 115 nm is formed.

FIG. 27 is a schematic diagram showing the atomic size of this curved surface. At 115 nm, the crystal lattice of Cu (a = 0.3614)
96 nm), which is only 320. Even if the corners are rounded, the flat region at the atomic level in the curved surface is limited to only a part. On the other hand, in order for straight and rigid molecules to be adsorbed, a dense metal atom and a flat metal surface at the atomic level are required. However, at the corners at the bottom of the fine wiring groove / through hole as described above, a high-index plane or a step-like structure in which metal atoms are coarse appears without fail.
A region where the inhibitor molecule cannot be adsorbed occurs due to steric hindrance. On the other hand, metal ions are much smaller than inhibitor molecules and can reach the entire metal surface regardless of surface shape. For this reason, the metal plating film grows preferentially from the corner of the bottom of the fine wiring groove / through hole where the plating inhibition effect by the inhibitor does not reach, and the wiring groove /
Through holes are buried.

Since the plating inhibitor functions by adsorbing on the metal surface, it functions sufficiently even if the concentration in the plating solution 53 is low. For example, if the concentration is 5 ppm or more, a sufficient effect of improving the embedding characteristics can be obtained. Can be Conversely, if the concentration of the inhibitor in the plating solution 53 becomes high, the amount of the inhibitor decomposed by a side reaction during the plating process increases, and the film quality of the metal plating film ( Flatness, density, specific resistance, etc.). Therefore,
Use at concentrations up to 1000 ppm at most is appropriate.

As another method for increasing the effect of the plating inhibitor, an inhibitor molecule is defined as having “a tertiary amine in a part of the molecular structure, and consisting of four or more atomic chains,
Having a linear conjugated system having a positive charge or an aromatic ring conjugated system having a positive charge, and at least one bond of nitrogen in the tertiary amine is directly bonded to the conjugated system; and It is also very effective to adopt a structure in which the positive charges are depolarized on a plurality of atoms. This is a structure that enhances the ability of the conjugated system to coat the metal surface and inhibit the plating reaction. In other words, on the negative electrode metal surface during plating, the conjugated system is attracted to the metal surface by its own positive charge and coats the metal surface, but when the positive charge is delocalized, multiple Since the atoms are attracted to the metal surface, the metal surface can be more stably coated.

When the electric charge is localized, the strength of the bond is strongly influenced by the surface condition of one point on the wafer surface, whereas the electric charge is delocalized and the electrostatic charge is formed at a plurality of points on the wafer surface. In the case where a specific bond is provided, the influence of the wafer surface is averaged, so that it is possible to form a stable bond that is hardly affected by the state of the wafer surface. If the nitrogen atom in the conjugate system provides a positive charge, it can be considered to fall under this structure. For example, the above-mentioned basic blue 3, methylene blue, basic red 12 and the like can be mentioned. Here, “positive charge is delocalized” means that it is not enough to simply say that some of the atoms constituting the conjugated system have a positive charge. is necessary. FIG. 28 shows the resonance structure of Basic Red 12. Although the positive charge appears to be present only on the two nitrogen atoms, the positive charge is actually delocalized on the carbon atoms that make up the central conjugated system. As described above, the resonance structure itself does not accurately indicate the position where the charge exists, but can be considered as indirect evidence that the charge is delocalized.

FIG. 29 shows a state in which a Cu film (second metal film) 35 having a thickness of about 500 nm is deposited on the upper portion of the silicon oxide film 21 and inside the wiring grooves 30 to 32 and the through holes 23 to 26. ing. According to the present embodiment, the Cu film 35 can be embedded without generating voids (voids) in the wiring grooves 30 to 32 and the through holes 23 to 26.

Next, as shown in FIG.
32 and Cu film 3 outside through holes 23 to 26
5. By removing the seed film 34 and the barrier film 33 by the chemical mechanical polishing method, the Cu wiring 36 embedded in the wiring grooves 30 to 32 and the through holes 23 to 26 is formed.
To 38 are formed.

Although the invention made by the inventor has been specifically described based on the embodiments of the present invention, the present invention is not limited to the above embodiments, and various modifications may be made without departing from the gist of the invention. Needless to say, it can be changed.

The composition of the plating solution is not limited to the above-described embodiment. The plating solution contains the above-mentioned plating inhibitor and can form a Cu film having a film quality such as specific resistance and flatness that can be practically used. Then, there is no problem in use in the present invention.

In the above-described embodiment, a dual-channel interconnection in which a buried Cu wiring is formed inside a wiring groove and a through hole is formed.
I explained the case where it was applied to the damascene process,
A single copper wire for forming a buried Cu wiring inside the wiring groove
It can also be applied to a damascene process.

In the above embodiment, the case where the embedded Cu wiring is formed has been described. However, a metal material other than Cu (for example, Ni, Z) is formed by utilizing a deposition reaction by electroplating.
(e.g., n, solder, etc.) in a fine through-hole.

[0053]

The effects obtained by typical ones of the inventions disclosed in the present application will be briefly described as follows.

According to the present invention, it is possible to embed a metal film without generating a void inside a fine wiring groove or through hole by utilizing a deposition reaction by electroplating. And high performance can be promoted.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part of a semiconductor substrate, illustrating a method of manufacturing a semiconductor integrated circuit device according to an embodiment of the present invention.

FIG. 2 is a fragmentary cross-sectional view of the semiconductor substrate, illustrating the method for manufacturing the semiconductor integrated circuit device according to one embodiment of the present invention;

FIG. 3 is a fragmentary cross-sectional view of the semiconductor substrate, illustrating the method for manufacturing the semiconductor integrated circuit device according to one embodiment of the present invention;

FIG. 4 is a fragmentary cross-sectional view of the semiconductor substrate, illustrating the method for manufacturing the semiconductor integrated circuit device according to one embodiment of the present invention;

FIG. 5 is a fragmentary cross-sectional view of the semiconductor substrate, illustrating the method for manufacturing the semiconductor integrated circuit device according to one embodiment of the present invention;

FIG. 6 is a fragmentary cross-sectional view of the semiconductor substrate, illustrating the method for manufacturing the semiconductor integrated circuit device according to one embodiment of the present invention;

FIG. 7 is a fragmentary cross-sectional view of the semiconductor substrate, illustrating the method for manufacturing the semiconductor integrated circuit device according to one embodiment of the present invention;

FIG. 8 is a fragmentary cross-sectional view of the semiconductor substrate, illustrating the method for manufacturing the semiconductor integrated circuit device according to one embodiment of the present invention;

FIG. 9 is a schematic configuration diagram of a plating apparatus used for forming a metal film.

FIG. 10 is a diagram illustrating the structure of a plating inhibitor of the present invention.

FIG. 11 is a diagram showing an example of a chemical structural formula of a plating inhibitor of the present invention.

FIG. 12 is a diagram showing an example of a chemical structural formula of a plating inhibitor of the present invention.

FIG. 13 is a diagram showing an example of a chemical structural formula of a plating inhibitor of the present invention.

FIG. 14 is a diagram showing an example of a chemical structural formula of a plating inhibitor of the present invention.

FIG. 15 is a diagram showing an example of a chemical structural formula of a plating inhibitor of the present invention.

FIG. 16 is a diagram showing an example of a chemical structural formula of a plating inhibitor of the present invention.

FIG. 17 is a graph showing the result of measuring the relationship between plating voltage and current.

FIGS. 18 (a) and (b) are diagrams illustrating a positional relationship between an amine nitrogen and a conjugated system.

FIG. 19 is a diagram showing an example of a chemical structural formula of a plating inhibitor of the present invention.

FIG. 20 is a diagram showing an example of a chemical structural formula of a plating inhibitor of the present invention.

FIG. 21 is a diagram showing an example of a chemical structural formula of a plating inhibitor of the present invention.

FIG. 22 is a diagram showing an example of a chemical structural formula of a plating inhibitor of the present invention.

FIGS. 23 (a) and (b) are diagrams illustrating a steric hindrance effect due to an alkyl group bonded to an amine nitrogen.

FIG. 24 is a diagram showing an example of a chemical structural formula of a plating inhibitor of the present invention.

FIG. 25 is a diagram showing an example of a chemical structural formula of a plating inhibitor of the present invention.

FIG. 26 is a diagram illustrating the relationship between the length of a conjugated system in the plating inhibitor of the present invention and the size of a crystal lattice of a metal formed by plating.

FIG. 27 is a schematic view showing a curved surface of a corner at the bottom of a wiring groove / through hole.

FIG. 28 is a diagram showing a resonance structure of Basic Red 12, which is one of the plating inhibitors of the present invention.

FIG. 29 is a fragmentary cross-sectional view of the semiconductor substrate, illustrating the method for manufacturing the semiconductor integrated circuit device according to one embodiment of the present invention;

FIG. 30 is a fragmentary cross-sectional view of the semiconductor substrate, illustrating the method for manufacturing the semiconductor integrated circuit device according to one embodiment of the present invention;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 semiconductor substrate (wafer) 2 element isolation groove 3 p-type well 4 n-type well 5 gate oxide film 6 gate electrode 7 n-type semiconductor region (source, drain) 8 p-type semiconductor region (source, drain) 9 silicon oxide film 10 , 11 contact hole 12-17 wiring 18 silicon nitride film 19 silicon oxide film 20 silicon nitride film 21 silicon oxide film 22 photoresist film 23-26 through hole 27 anti-reflection film 28 photoresist film 30-32 wiring groove 33 barrier film 34 Seed film (first metal film) 35 Cu film (second metal film) 36 to 38 Embedded Cu wiring 50 Plating device 51 Plating tank 52 Plating solution storage tank 53 Plating solution 54 Power supply 55 Holder pin 56 Wafer holder 57 Anode 58 Hole 59 Pump 60 Filter 61 Piping Qn n channel MISFET Qp P-channel MISFET

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takeyuki Itabashi 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Inside the Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Toshio Namba 7-chome, Omika-cho, Hitachi City, Ibaraki Prefecture No. 1-1 Inside Hitachi, Ltd. Hitachi Laboratory (72) Inventor Kinya Kobayashi 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture F-term in Hitachi, Ltd. Hitachi Laboratory F-term (reference) 4M104 BB01 BB04 BB30 CC01 DD08 DD16 DD17 DD37 DD52 FF18 FF22 GG10 GG14 HH13 5F033 HH04 HH11 HH19 HH21 HH33 HH34 JJ01 JJ11 JJ19 JJ21 JJ32 JJ33 KK19 KK33 MM02 SS0811 NN08 NN13 NN07 NN07 NN07 WW04 XX02 5F048 AA07 AC03 BA01 BB05 BB09 BB13 BF01 BF07 BF16 CA01 CA02

Claims (11)

[Claims] 1. A step of forming a wiring groove or a through hole in an insulating film on a main surface of a semiconductor substrate, and then forming a first metal film covering an upper surface of the insulating film and an inner wall of the wiring groove or the through hole. And embedding the second metal film inside the wiring groove or through-hole by depositing a second metal film on the surface of the first metal film using a metal deposition reaction by electroplating. A method of manufacturing a semiconductor integrated circuit device, comprising: preventing deposition of the second metal film on an upper surface of the insulating film and near an opening of the wiring groove or through hole; and near a bottom of the wiring groove or through hole. 3. A method for manufacturing a semiconductor integrated circuit device, comprising using a plating solution to which a plating inhibitor for causing the deposition of the second metal film to proceed preferentially is added. 2. The method for manufacturing a semiconductor integrated circuit device according to claim 1, wherein the plating inhibitor comprises a tertiary amine and four or more atomic chains in a part of a molecular structure, and has a positive charge. A linear conjugated system or a positively charged aromatic ring conjugated system, wherein at least one of nitrogen in the tertiary amine is
A method for manufacturing a semiconductor integrated circuit device, characterized in that a bond is a substance having a chemical structure directly bonded to the conjugated system. 3. The method for manufacturing a semiconductor integrated circuit device according to claim 2, wherein the substance having the chemical structure is such that nitrogen in the tertiary amine is composed of nitrogen and carbon.
A method of manufacturing a semiconductor integrated circuit device, wherein the method is a part of a six-membered ring or a six-membered ring, and the five-membered ring or the six-membered ring contains at least a part of atoms constituting the conjugated system. 4. The method for manufacturing a semiconductor integrated circuit device according to claim 3, wherein one methyl group is bonded to nitrogen in said tertiary amine. . 5. The method for manufacturing a semiconductor integrated circuit device according to claim 2, wherein the length of the conjugate system is 1 nm or more. 6. The method of manufacturing a semiconductor integrated circuit device according to claim 2, wherein the positive charges of the conjugated system are delocalized on a plurality of atoms. Method. 7. The method of manufacturing a semiconductor integrated circuit device according to claim 2, wherein the concentration of the substance having the chemical structure in the plating solution is 5 ppm or more and 1000 ppm.
A method for manufacturing a semiconductor integrated circuit device, wherein the method is within the following range. 8. The method for manufacturing a semiconductor integrated circuit device according to claim 2, wherein the substance having the chemical structure is basic blue 3, diazine black, methyl violet, methylene blue, tetranitro blue tetrazonium. A method of manufacturing a semiconductor integrated circuit device, comprising: chloride, 2,3,5-triphenyl-2H-tetrazonium chloride, basic red 12, strain all, or cyanine dye. 9. The method for manufacturing a semiconductor integrated circuit device according to claim 1, wherein a width of said wiring groove or a diameter of said through hole is 250 nm or less. . 10. The method of manufacturing a semiconductor integrated circuit device according to claim 1, wherein said first metal film and said second metal film are made of a metal containing Cu as a main component. A method for manufacturing a circuit device. 11. The method of manufacturing a semiconductor integrated circuit device according to claim 1, wherein said second metal film is embedded in said wiring groove or through-hole, and then said second metal film is formed outside said wiring groove or through-hole. A method of manufacturing a semiconductor integrated circuit device, comprising forming a wiring made of the second metal film inside the wiring groove or through hole by removing the second metal film by a chemical mechanical polishing method.