JP3192968B2 - Polishing liquid for copper-based metal and method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polishing liquid for copper-based metal and a method for manufacturing a semiconductor device.

[0002]

2. Description of the Related Art In forming a wiring layer, which is one of the manufacturing steps of a semiconductor device, an etch-back technique is employed for the purpose of eliminating a step on a surface. In this etch-back technique, a wiring-shaped groove is formed in an insulating film on a semiconductor substrate, a Cu film is deposited on the insulating film including the groove, and the Cu film is polished using a polishing apparatus and a polishing liquid. Then, a buried wiring layer is formed by leaving a Cu film only in the trench.

Meanwhile, as the polishing liquid, a liquid made of pure water in which polishing grains such as colloidal silica are dispersed has been used. However, when the polishing liquid is supplied to a polishing pad of a polishing apparatus and a Cu film formed on a substrate is polished while applying a predetermined load to the polishing pad, simply using the polishing abrasive grains and the polishing pad. Only mechanical polishing is performed on the Cu film.
For this reason, there was a problem that the polishing rate was as low as 10 nm / min.

On the other hand, J. A. Electrochem. So
c. , VoL. 138. No. 11, 3460 (199
1), VMIC Conference, ISMIC-
101/92/0156 (1992) or VMIC
Conference, ISMIC-102 / 93/0
205 (1993) includes amine-based colloidal silica slurry or K ₃ Fe (CN) ₆ , K ₄ (CN) ₆ ,
A polishing liquid for a Cu film or a Cu alloy film made of a slurry to which Co (NO ₃ ) ₂ is added is disclosed.

However, there is no difference in the etching rate of the Cu film between the time of immersion and the time of polishing of the polishing liquid. As a result, after the above-described etch-back step, C
When the u wiring layer is in contact with the polishing solution, there is no difference in the etching rate of the Cu film between the time of immersion and the time of polishing.
The wiring layer is further etched by the polishing liquid. Therefore, since the surface position of the Cu wiring layer in the groove is lower than the surface of the insulating film, it is difficult to form a wiring layer flush with the surface of the insulating film, and the flatness is impaired. Further, the formed buried Cu wiring layer has a higher resistance value than the Cu wiring layer buried flush with the surface of the insulating film.

Japanese Patent Application Laid-Open No. Hei 7-233485 discloses a polishing liquid for copper-based metal containing at least one organic acid selected from aminoacetic acid and amidosulfuric acid, an oxidizing agent and water. This copper-based polishing liquid exhibits an etching rate difference of several times to several tens times between immersion of copper (Cu) or copper alloy (Cu alloy) and polishing. That is, aminoacetic acid, which is a component of the polishing liquid, reacts with Cu hydrate to form a complex that dissolves in water, as shown in the following reaction formula.

Cu (H ₂ O) ₄ ²⁺ + 2H ₂ NCH ₂ CO
OH → Cu (H ₂ NCH ₂ COOH) ₂ + 4H ₂ O + 2
H ⁺ Cu does not react with the mixed liquid of aminoacetic acid and water. In such a reaction system, by adding an oxidizing agent (for example, hydrogen peroxide), the reaction proceeds in a direction indicated by an arrow in the above reaction formula, and Cu is etched. For example, when a Cu film is immersed in the polishing liquid, an oxide layer is generated on the surface of the Cu film, and etching (dissolution) of Cu is suppressed. On the other hand, when the Cu film is polished with a polishing pad in which the polishing liquid is present, the oxide layer is mechanically polished by the polishing pad, so that pure Cu is exposed on the surface, and amino acid and hydrogen peroxide in the polishing liquid are removed. The action sharpens the chemical polishing. That is, in the polishing process, pure Cu is always exposed on the polished surface of the Cu film, and chemical etching is performed by aminoacetic acid and hydrogen peroxide in the polishing liquid. However, the polishing liquid may slightly dissolve Cu or Cu alloy during a period in which no oxide layer is formed on the surface immediately after polishing of Cu or Cu alloy.

Japanese Patent Application Laid-Open No. 7-233485 discloses a method of manufacturing a semiconductor device in which a wiring material film made of copper or a copper alloy is etched back by using the polishing liquid for a copper-based metal to form a buried wiring. It has been disclosed.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to dissolve the Cu or the like at all during immersion of copper (Cu) or a copper alloy (Cu alloy), and to use the Cu or Cu alloy at the time of polishing. It is an object of the present invention to provide a copper-based metal polishing liquid capable of polishing at a specific speed.

Another object of the present invention is to form at least one member selected from a groove and an opening in an insulating film on a semiconductor substrate, and to form copper (Cu) or copper alloy (Cu) deposited on the insulating film. It is an object of the present invention to provide a method of manufacturing a semiconductor device capable of etching back a wiring material film made of an alloy) in a short time and forming a highly accurate embedded wiring layer flush with the surface of an insulating film.

[0011]

The polishing liquid for copper-based metal according to the present invention is a water-soluble organic compound which reacts with copper to form a copper complex which is hardly soluble in water and which is more brittle than copper. It is characterized by containing an acid, abrasive grains and water.

[0012] A method of manufacturing a semiconductor device according to the present invention comprises:
Forming at least one member selected from a groove and an opening corresponding to the shape of a wiring layer in an insulating film on a semiconductor substrate; and the insulating film including at least one member selected from the groove and the opening A step of forming a wiring material film made of copper or a copper alloy thereon, and reacting with copper to be hardly soluble in water,
The wiring material film is polished until the surface of the insulating film is exposed using a water-soluble organic acid that forms a copper complex that is more mechanically weaker than copper, a polishing solution containing abrasive grains and water. Forming the wiring material film in the insulating film to form a wiring layer. Semiconductor having a multilayer wiring structure according to the present invention
The manufacturing method of the body device is performed on a semiconductor substrate on which a diffusion layer is formed.
A groove corresponding to the shape of the buried wiring layer in the first insulating film of FIG.
And the first opening corresponding to the shape of the first via fill
Forming at least one member is said member
A barrier layer on the first insulating film including the inner side surface and the bottom surface of the substrate
Forming a copper layer on the barrier layer including the member
Or forming a first wiring material film made of a copper alloy
If, by reacting with copper sparingly soluble in water, and mechanically than copper
Water-soluble organic acids that form fragile copper complexes, abrasive grains and
The first wiring material film and the polishing liquid containing water and water are used.
And the barrier layer is sequentially polished to form the grooves.
A buried wiring layer is formed or a first via is formed in the first opening.
Step of forming an afill or both
And from the embedded wiring layer and the first via fill.
The first insulating film including at least one selected wiring portion
Forming a second insulating film on the bottom in the second insulating film
Part forms a second opening reaching the first via fill
A step, Doma on said second insulating film including the second opening
Other forming a second wiring materials film made of copper alloy,
Reacts with copper and is hardly soluble in water, and is more mechanically weaker than copper
Water soluble organic acids, abrasive grains and water
Polishing the second wiring material film using a polishing solution containing
Forming a second via fill in the second opening.
And a step of forming.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a polishing liquid for a copper-based metal according to the present invention will be described in detail. The polishing liquid for a copper-based metal contains a water-soluble organic acid, a polishing abrasive, and water that react with copper to form a copper complex that is hardly soluble in water and that is mechanically more brittle than copper.

Examples of the organic acid include 2-quinoline carboxylic acid (quinaldic acid), 2-pyridine carboxylic acid, 2,6-pyridine carboxylic acid, and quinone.

Preferably, the organic acid is contained in the polishing liquid in an amount of 0.1% by weight or more. When the content of the organic acid is less than 0.1% by weight, it is difficult to sufficiently generate a copper complex that is more mechanically weaker than copper on the surface of Cu or a Cu alloy. As a result, it becomes difficult to sufficiently increase the polishing rate of Cu or Cu alloy during polishing.
More preferably, the content of the organic acid is 0.3 to 1.2% by weight.

The abrasive grains are made of at least one material selected from silica, zirconia, cerium oxide and alumina. The abrasive grains are preferably based on alumina particles having a hardness particularly suitable for polishing. That is, it is preferable to form abrasive grains from alumina particles alone or mixed particles of alumina particles and silica particles such as colloidal silica.

Preferably, the abrasive grains have an average particle size of 0.02 to 0.1 μm and have a spherical shape or a shape close to a sphere. When the Cu or Cu alloy is polished with a polishing liquid containing such polishing abrasive grains, damage to the Cu or Cu alloy surface can be suppressed. In particular, γ-alumina particles are preferable because spherical particles can be easily produced in their production.

The polishing abrasive grains are contained in the polishing liquid in an amount of 1 to 20.
% By weight. When the content of the abrasive grains is less than 1% by weight, it is difficult to sufficiently achieve the effect. On the other hand, when the content of the abrasive grains is 20
If the amount is more than 10% by weight, the viscosity and the like of the polishing liquid are increased, and the handling becomes difficult. More preferably, the content of the abrasive grains is 2 to 10
% By weight.

The polishing liquid according to the present invention is allowed to further contain a copper complex formation promoter. Examples of such a copper complex formation promoter include hydrogen peroxide (H ₂ O ₂ ),
An oxidizing agent such as sodium hypochlorite (NaClO) can be used.

It is preferable that the oxidizing agent is contained in the polishing liquid at a weight ratio of 10 times or more of the organic acid. If the content of the oxidizing agent is less than 10 times the weight of the organic acid by weight, it becomes difficult to sufficiently promote the formation of a copper complex on the surface of Cu or a Cu alloy. The content of the oxidizing agent is more preferably 30 times or more, more preferably 50 times or more, by weight based on the organic acid.

The polishing liquid according to the present invention is allowed to further contain a pH adjuster such as an alkaline agent. As such an alkaline agent, for example, potassium hydroxide and choline are preferable.

The polishing liquid according to the present invention allows the addition of a nonionic, zwitterionic, anionic or cationic surfactant. Examples of the nonionic surfactant include polyethylene glycol phenyl ether and ethylene glycol fatty acid ester. As the zwitterionic surfactant,
For example, imidazoribetaine and the like can be mentioned. Examples of the anionic surfactant include sodium dodecyl sulfate. Examples of the cationic surfactant include stearin trimethylammonium chloride. These surfactants may be used in the form of a mixture of two or more.
The polishing liquid further containing such a surfactant can enhance selective polishing of Cu or a Cu alloy and an insulating film such as a SiN film and SiO ₂ as described later.

It is preferable that the surfactant is added to the polishing liquid at a rate of 1 mol / liter or more. When the addition amount of the surfactant is less than 1 mol / liter, it becomes difficult to enhance selective polishing of Cu or a Cu alloy and an insulating film such as SiO ₂ during polishing. A more preferable addition amount of the surfactant is in the range of 10 to 100 mol / liter.

For polishing a Cu film or a Cu alloy film formed on a substrate, for example, with the polishing liquid for a copper-based metal according to the present invention, a polishing apparatus shown in FIG. 1 is used. That is, the turntable 1 is covered with a polishing pad 2 made of cloth, for example. A supply pipe 3 for supplying a polishing liquid is disposed above the polishing pad 2. A substrate holder 5 having a support shaft 4 on the upper surface is arranged above the polishing pad 2 so as to be vertically movable and rotatable. In such a polishing apparatus, the holder 5
By holding the substrate 6 with its polishing surface (eg, Cu film) facing the polishing pad 2 and supplying the polishing liquid 7 having the above-described composition from the supply pipe 3, the substrate 6 is supported by the support shaft 4. Is applied to the polishing pad 2, and the Cu film on the substrate is polished by rotating the holder 5 and the turntable 1 in opposite directions.

The polishing liquid for a copper-based metal according to the present invention described above is a water-soluble organic acid which reacts with copper to form a copper complex which is hardly soluble in water and which is more brittle than copper. Since it contains abrasive grains and water, it does not dissolve the Cu or the like at the time of immersion of Cu or Cu alloy,
The u or Cu alloy can be polished at a practical rate. Here, the practical polishing rate means three times or more that in the case of using a polishing liquid containing only conventional polishing abrasive grains.

That is, an organic acid, eg, 2-quinoline carboxylic acid, which is a component of the polishing liquid, reacts with Cu hydrate (Cu ion) as shown in the following reaction formula 1 to form water. It has the property of forming poorly soluble complexes.

[0027]

Embedded image

The copper complex formed on the surface of Cu or Cu alloy by the above reaction formula is not dissolved in water,
Since it is more fragile than u, it is easily polished by a polishing process.

Further, the polishing solution containing a copper complex formation accelerator such as an oxidizing agent promotes the formation of a copper complex according to the above reaction formula, and reduces the amount of Cu or Cu alloy during polishing by using only conventional abrasive grains. Can be polished at a speed 5 times or more as compared with a polishing liquid containing.

FIG. 2 shows the relationship between the polishing rate (processing rate) and the temperature of the polishing liquid when the Cu film formed on the substrate was polished using the polishing liquid of the present invention and the conventional polishing liquid. It is plotted in relation. The polishing liquid of the present invention contains 0.3% by weight of an organic acid (for example, 2-quinoline carboxylic acid), 16.7% by weight of a copper complex formation promoter (for example, hydrogen peroxide), 1.3% by weight of γ-alumina particles, It has a composition consisting of 4.0% by weight of colloidal silica and water. Conventional polishing liquid is γ
1.3% by weight of alumina particles, 4.0 of colloidal silica
It has a composition consisting of weight percent and water. A in FIG.
A characteristic line by the polishing liquid of the present invention, and b is a characteristic line by the conventional polishing liquid. The polishing was performed using the polishing apparatus shown in FIG. That is, the substrate on which the Cu film is formed on the substrate holder 5 is held upside down so that the Cu film faces the polishing pad 2 side made of, for example, SUBA800 (trade name, manufactured by Rodel-Nitta), and is supported by the support shaft 4. A polishing liquid is applied from the supply pipe 3 to the polishing pad 2 at a rate of 300 g / cm ^{2 while} the turntable 1 and the holder 5 are rotated in the opposite directions at a speed of 100 rpm. The polishing process was performed by supplying to the polishing pad 2 at the speed described above.

As is apparent from FIG. 2, the polishing rate of the Cu film by the polishing liquid of the present invention (characteristic line a) is about six times the polishing rate by the conventional polishing liquid containing only the abrasive grains (characteristic line b). It turns out that it becomes about.

FIG. 3 shows a polishing liquid composed of 2-quinolinecarboxylic acid, hydrogen peroxide, abrasive grains (γ-alumina particles and colloidal silica), and water. Is constant at 16.7% by weight, 1.3% by weight and 4.0% by weight, respectively, and when the content of 2-quinolinecarboxylic acid is changed, the Cu film formed on the substrate is changed. It is a plot of the polishing rate (processing rate) during the polishing process. In addition,
The polishing treatment was performed using the polishing apparatus shown in FIG. 1 in the same procedure as described above.

As is apparent from FIG. 3, the polishing rate of Cu increases as the content of 2-quinolinecarboxylic acid in the polishing liquid increases. FIG. 4 shows a polishing liquid having a composition consisting of 2-quinoline carboxylic acid, hydrogen peroxide, abrasive grains (γ-alumina particles and colloidal silica) and water. During the polishing treatment of the Cu film formed on the substrate when the content is fixed at 0.3 wt%, 1.3 wt% and 4.0 wt%, respectively, and the content of hydrogen peroxide is changed. 2 is a plot of the polishing rate (processing rate) of the sample. The polishing was performed using the polishing apparatus shown in FIG. 1 in the same procedure as described above.

As is clear from FIG. 4, when a polishing liquid containing no hydrogen peroxide is used during the polishing treatment of the Cu film, the processing speed of the Cu film is about 51 nm / min. As the content increases, the processing speed of the Cu film increases, reaching up to about 90 nm / min with a polishing liquid containing 9% by weight or more. In other words, the hydrogen peroxide solution contributes as an accelerator for the complex formation, and the underlying Cu or Cu alloy exposed in the mechanical polishing process by the polishing pad and the polishing abrasive grains in the polishing solution is quickly changed according to the above reaction formula. It is thought to produce a copper complex with fragile properties.

In fact, as shown in FIG.
A Cu film 12 having irregularities is formed thereon, and a polishing liquid (2-quinoline carboxylic acid, γ-alumina particles, colloidal silica, and hydrogen peroxide each having a composition of high polishing rate) shown in FIG. 3% by weight, 1.3% by weight,
After immersion for 3 minutes in 4.0 wt% and 16.7 wt%), a copper complex layer 13 is formed on the surface of the Cu film 12 as shown in FIG. The surface of the Cu film immersed in the polishing liquid was analyzed by XPS (X-ray photoelectron spectroscopy). As a result, C
A large amount of carbon was detected on the surface of the u film, and only a small amount of Cu was detected. Further, the thickness of the copper complex layer was examined by AES (Auger electron spectroscopy). as a result,
The thickness of the copper complex layer was about 20 nm.

When the Cu film 12 having the altered layer 13 shown in FIG. 5B on its surface is polished with a polishing pad in which the polishing liquid is present as shown in FIG. And Cu film 1 as shown in FIG.
The copper complex layer 13 corresponding to the second convex portion is mechanically easily polished by the pad, so that pure Cu is exposed on the surface. When the Cu surface immediately after this polishing was analyzed by XPS (X-ray photoelectron spectroscopy), only Cu was detected and almost no oxidation was performed. That is, in the polishing process, Cu surface
By mechanically removing (polishing) the copper complex layer with a polishing pad or the like while the more fragile copper complex layer is being generated, the surface processing of the Cu film proceeds.

The Cu polishing rate (about 15 nm / min) when using the above-mentioned polishing liquid without 2-quinolinecarboxylic acid shown in FIG. 3 and the polishing liquid (2 -Cu polishing rate (approximately 51 nm / m) when quinoline carboxylic acid, abrasive grains and water are used.
As apparent from the comparison with (i), the polishing liquid of the present invention having a composition consisting of 2-quinoline carboxylic acid, polishing abrasive grains and water is less than the conventional polishing liquid without the addition of 2-quinoline carboxylic acid. It can be seen that the polishing rate is at least three times higher.

Therefore, the polishing liquid according to the present invention is Cu
Alternatively, the Cu or the like is not dissolved at all during the immersion of the Cu alloy, and the Cu or the Cu alloy is polished at a practical speed (three times or more the speed in the case of using a polishing liquid containing conventional abrasive grains) during the polishing. Can be polished. Therefore, it is possible to avoid a problem that the etching amount of Cu fluctuates due to the supply timing of the polishing liquid or the like in the polishing process, and the operation can be performed easily.

When polishing the Cu film on the substrate by the polishing apparatus, the Cu film is polished only while the polishing pad is in contact (sliding contact) with a predetermined load, and the polishing pad is polished. Since polishing is stopped immediately after leaving the Cu film, so-called over-etching, in which the Cu film is further etched after the polishing process, can be prevented.

Further, as shown in FIG. 5C, the Cu film 12 having the irregularities is not etched from the side in the polishing step, and can be etched sequentially from the surface of the convex portion in contact with the polishing pad. This is extremely suitable for an etch-back technique described later. The surface of the polished Cu film is brought into contact with the polishing solution to form the above-mentioned copper complex layer, but since its thickness is extremely thin at 20 nm, the copper complex layer is removed to remove the pure Cu surface. When the film is exposed, it is possible to prevent the Cu film from being excessively reduced.

The polishing rate (processing rate) of Cu can be controlled by adjusting the pH of the polishing liquid according to the present invention by adding an alkaline agent such as choline. FIG.
Is 2-quinoline carboxylic acid, γ-alumina particles, colloidal silica, and hydrogen peroxide, respectively.
3% by weight, 1.3% by weight, 4.0% by weight, 16.7% by weight, and a film is formed on a substrate using a polishing liquid containing choline and adjusted to a pH of 4 to 9.5. FIG. 4 is a characteristic diagram showing a polishing rate (processing speed) of the Cu film when the Cu film obtained is polished. As shown in FIG. 6, as the pH increases, the polishing rate of the Cu film decreases, and particularly when the pH is 8 or more, the polishing rate extremely decreases.

By adding a nonionic, zwitterionic, anionic or cationic surfactant to the polishing liquid according to the present invention, Cu or Cu alloy and an insulating material such as SiO ₂ can be used during polishing. Selective polishing with the film can be improved. FIG. 7 shows, for example, 0.3% by weight, 1.3% by weight, 4.0% by weight of 2-quinolinecarboxylic acid, γ-alumina particles, colloidal silica and hydrogen peroxide, respectively.
Cu film formed on a substrate using a polishing liquid containing 16.7% by weight of sodium dodecyl sulfate (SDS), which is an anionic surfactant, and plasma silicon nitride. Film (P-SiN film) and SiO ₂
FIG. 4 is a characteristic diagram showing polishing rates (processing rates) of the films when the films are polished. In FIG. 7, A is a characteristic line indicating the polishing rate of the Cu film, B is a characteristic line indicating the polishing rate of the P-SiN film, C is a characteristic line indicating the polishing rate of the SiO ₂ film,
It is. As shown in FIG. 7, the polishing rate of the Cu film increases as the amount of SDS added increases. On the other hand, the polishing rate of the P-SiN film and the SiO ₂ film with an increase in the amount of SDS is lowered, the amount of SDS is 10m mol / liter, the polishing of the P-SiN film and the SiO ₂ film The speed becomes almost zero. Therefore, the selective polishing of Cu with a P-SiN film and an insulating film such as SiO ₂ can be enhanced by the addition of SDS. Surfactants that enhance such selective polishing properties include not only SDS, which is an anionic surfactant, but also an amphoteric surfactant, a cationic surfactant, and a nonionic surfactant, as shown in FIG. But it can be achieved as well.

In the polishing liquid according to the present invention, 2-
Reacts with copper other than quinoline carboxylic acid and is hardly soluble in water,
Even when water-soluble organic acids, such as 2-pyridinecarboxylic acid, 2,6-pyridinecarboxylic acid, and quinone, which form copper complexes that are more mechanically weaker than copper, are used as described above, Cu or Cu alloy is used. Cu or the Cu alloy can be polished at a practical rate during the polishing without dissolving the Cu or the like at all.

Next, a method for manufacturing a semiconductor device according to the present invention will be described. The method of manufacturing a semiconductor device includes a step of forming at least one member selected from a groove and an opening corresponding to the shape of a wiring layer in an insulating film on a semiconductor substrate; Depositing a wiring material film made of copper or a copper alloy on the insulating film including at least one member, and a copper complex which reacts with copper, is hardly soluble in water, and is mechanically weaker than copper. The wiring material film is formed on the insulating film by subjecting the wiring material film to a polishing treatment until the surface of the insulating film is exposed using a polishing liquid containing a water-soluble organic acid, polishing abrasive grains and water. Forming a buried wiring layer flush with the surface.

As the insulating film, for example, a silicon oxide film, a boron-doped glass film (BPSG film), a phosphorus-doped glass film (PSG film), or the like can be used. On this insulating film, silicon nitride, carbon, alumina, boron nitride,
The polishing stopper film made of diamond or the like is allowed to be covered.

As the Cu alloy, for example, Cu—Si
Alloy, Cu-Al alloy, Cu-Si-Al alloy, Cu-
An Ag alloy or the like can be used. Cu or Cu
The wiring material film made of an alloy is deposited by sputter deposition, vacuum deposition, or the like.

It is preferable that the content of the organic acid in the polishing liquid is in the same range as the above-mentioned polishing liquid for copper-based metal. Examples of the abrasive grains in the polishing liquid include alumina particles, silica particles, cerium oxide particles, and zirconia particles. The abrasive grains are preferably based on alumina particles having a hardness particularly suitable for polishing. That is, it is preferable to form abrasive grains from alumina particles alone or mixed particles of alumina particles and silica particles such as colloidal silica.

The abrasive grains preferably have an average particle size of 0.02 to 0.1 μm and have a spherical or spherical shape. When the polishing treatment is performed using a polishing liquid containing such polishing abrasive grains, damage to the Cu or Cu alloy surface can be suppressed. In particular, γ-alumina particles are preferable because spherical particles can be easily produced in their production.

The content of the abrasive grains is preferably 1 to 20% by weight, more preferably 2 to 20% by weight, as in the above-mentioned polishing liquid for copper-based metal.
It is preferably in the range of ７7% by weight. The polishing liquid is allowed to further contain a copper complex formation promoter. Examples of such a copper complex formation promoter include hydrogen peroxide (H ₂ O ₂ ) and sodium hypochlorite (NaClO).
An oxidizing agent such as

The oxidizing agent is preferably contained in the polishing liquid at a weight ratio of at least 10 times the weight of the organic acid. If the content of the oxidizing agent is less than 10 times the weight of the organic acid by weight, it becomes difficult to sufficiently promote the formation of a copper complex on the surface of Cu or a Cu alloy. The content of the oxidizing agent is more preferably 30 times or more, more preferably 50 times or more, by weight based on the organic acid.

The polishing liquid is allowed to further contain a pH adjuster such as an alkaline agent. As such an alkali agent, for example, potassium hydroxide and trimethylammonium hydroxide are preferable.

The polishing liquid allows a nonionic, zwitterionic, anionic or cationic surfactant to be further added. Examples of the nonionic surfactant include polyethylene glycol phenyl ether,
Examples include ethylene glycol fatty acid esters. Examples of the zwitterionic surfactant include imidazoribetaine and the like. Examples of the anionic surfactant include sodium dodecyl sulfate. Examples of the cationic surfactant include stearin trimethylammonium chloride and the like. These surfactants may be used in the form of a mixture of two or more.

The polishing process using the polishing liquid is performed using, for example, the above-described polishing apparatus shown in FIG. FIG.
In the polishing process using the polishing apparatus shown in (1), the weight applied to the polishing pad by the substrate held by the substrate holder is appropriately selected according to the composition of the polishing liquid. For example, in the case of a polishing liquid having a composition comprising 2-quinolinecarboxylic acid, which is an organic acid, polishing abrasive grains, and water, the weight is 50 to 1000 g /
cm ² is preferred.

In the manufacture of the semiconductor device according to the present invention, a barrier layer is formed on the insulating film including at least one member selected from the groove and the opening on the semiconductor substrate before depositing the wiring material film. Allow to do. By forming such a barrier layer in the insulating film including at least one member selected from the groove and the opening, a wiring material film such as Cu is deposited, and embedded by the etch back by the barrier layer. A wiring layer can be formed in at least one of the groove and the opening. As a result, the diffusion of Cu, which is a wiring material, into the insulating film is prevented by the barrier layer, so that contamination of the semiconductor substrate by Cu can be prevented.

The barrier layer is made of, for example, TiN, Ti, N
b, W or CuTa alloy. Such a barrier layer preferably has a thickness of 15 to 50 nm.
The method of manufacturing a semiconductor device according to the present invention described above includes:
At least one member selected from a groove and an opening corresponding to a wiring layer is formed in an insulating film on a semiconductor substrate, and a wiring material film made of Cu or a Cu alloy is deposited on the insulating film including the member. Further, a polishing liquid containing a water-soluble organic acid, polishing abrasive grains and water, which react with copper to form a copper complex which is hardly soluble in water and mechanically weaker than copper, is used, for example, as shown in FIG. The wiring material film is polished until the surface of the insulating film is exposed using a polishing apparatus shown in FIG. The polishing liquid may be a Cu film or a C film as described above.
The Cu film or Cu alloy film is not dissolved at all during the immersion of the u alloy film, and the Cu film or Cu
The alloy film can be polished at a practical speed (three times or more the speed in the case of using a polishing liquid containing conventional polishing abrasive grains). In particular, when a polishing solution further containing a copper complex formation accelerator such as an oxidizing agent is used, the Cu film or Cu alloy film is polished at a rate five times or more as compared with a polishing solution containing conventional polishing abrasive grains. It becomes possible to do. As a result, in the polishing step, the wiring material film is sequentially polished from its surface, that is, so-called etch back is performed.
A buried wiring layer made of Cu or a Cu alloy can be formed on the surface of the insulating film flush with the surface of the insulating film. Further, the wiring layer after the etch-back step is brought into contact with the polishing liquid, but does not dissolve Cu or Cu alloy at all, as described above, so that the wiring layer can be prevented from being dissolved (etched).

Therefore, a semiconductor device having a buried wiring layer with high precision and a structure having a flat surface can be manufactured. The surface of the buried wiring layer formed in the insulating film is brought into contact with the polishing solution to form the above-mentioned copper complex layer, but since the thickness is extremely thin at 20 nm, the copper complex layer is removed. When the pure Cu surface is exposed, the buried wiring layer can be prevented from being excessively reduced in film thickness.

Further, by using a polishing liquid containing polishing abrasive grains having a spherical shape or a shape close to a sphere, the occurrence of cracks and scratches in the wiring material film in the etch-back step can be suppressed. Buried wiring layer having a high density can be formed.

Further, if a polishing stopper film made of silicon nitride, carbon, alumina, boron nitride, diamond, or the like is previously coated on the insulating film, the polishing of the insulating film in the etching back step of the wiring material film is prevented. it can. As a result, thinning of the underlying insulating film can be suppressed, and a semiconductor device with high withstand voltage can be manufactured.

Further, if a polishing liquid further containing a nonionic, zwitterionic, anionic, or cationic surfactant is used, a wiring material film made of Cu or a Cu alloy can be used in the etch-back step. Selective polishing with an insulating film such as ₂ can be improved. As a result, thinning of the underlying insulating film can be suppressed, and a semiconductor device with high withstand voltage can be manufactured. In addition, by using a polishing liquid containing such a surfactant, it is possible to easily remove contaminants such as fine wiring materials and organic substances remaining on the insulating film in cleaning after the etch-back step. become. As a result, it is possible to manufacture a semiconductor device having a clean surface from which organic substances and residual wiring materials on the surface of the insulating film have been removed.

[0060]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. (Embodiment 1) First, as shown in FIG. 9A, a 1000 nm-thick interlayer insulating film is formed on a silicon substrate 21 on which a diffusion layer such as a source and a drain (not shown) is formed by a CVD method. After depositing the SiO ₂ film 22,
A plurality of grooves 2 having a shape corresponding to a wiring layer and having a depth of 500 nm are formed in the SiO ₂ film 22 by a photoetching technique.
3 was formed. Subsequently, as shown in FIG. 9B, a barrier layer 24 made of TiN having a thickness of 15 nm and a Cu film 25 having a thickness of 600 nm are formed in this order on the SiO ₂ film 22 including the groove 23 by sputtering. Deposited.

Next, FIG. 1 is placed on the substrate holder 5 of the polishing apparatus shown in FIG. The substrate 21 shown in FIG. 9B is held upside down, and the substrate is supported on the turntable 1 by the support shaft 4 of the holder 5 (trade name of Rodel-Nitta);
300 g / cm for polishing pad 2 made of SUBA800
^{2 and} the turntable 1 and the holder 5
The polishing liquid is supplied from the supply pipe 3 to the polishing pad 2 at a rate of 12.5 ml / min while rotating the polishing liquid in the opposite directions at a speed of 100 rpm, and the Cu film 25 and the barrier layer 24 deposited on the substrate 21 are rotated. To the SiO ₂ film 2
Polishing was performed until the surface of No. 2 was exposed. Here, the polishing liquid used was pure water containing 0.3% by weight of 2-quinolinecarboxylic acid, 1.4% by weight of γ-alumina particles having an average particle diameter of 30 nm, and 4.1% by weight of colloidal silica. . In the polishing step, the polishing liquid did not undergo any etching at the time of contact with the Cu film, and the polishing rate at the time of polishing with the polishing pad was about 51 nm / min. For this reason, in the polishing step, the convex Cu film 25 shown in FIG. 9B is preferentially polished from the surface that is in mechanical contact with the polishing pad, and the exposed barrier layer 24 is polished. An etch back was made. As a result, as shown in FIG. 9C, the barrier layer 24 remains in the trench 23 and the trench 23 covered with the barrier layer 24 is buried flush with the surface of the SiO ₂ film 22. The Cu wiring layer 26 was formed.

After the weight of the polishing pad 2 by the holder 5 of the polishing apparatus is released and the rotation of the turntable 1 and the holder 5 is stopped, the Cu wiring layer 26 is brought into contact with the polishing liquid. However, it was not dissolved (etched).

(Example 2) First, for example, a 1000 nm-thick Si film as an interlayer insulating film was formed on a silicon substrate having a diffusion layer such as a source and a drain formed on the surface by CVD.
After the O ₂ film is deposited, the SiO ₂ film has a depth of 500 corresponding to the wiring layer by a photo-etching technique.
A plurality of grooves of nm were formed. Then, a 15 nm thick T is deposited on the SiO ₂ film including the groove by sputtering.
A barrier layer made of iN and a Cu film having a thickness of 600 nm were deposited in this order.

Then, the substrate is held upside down on the substrate holder 5 of the polishing apparatus shown in FIG. 1 and the substrate is turned on the turntable 1 by the support shaft 4 of the holder 5.
A load of 300 g / cm ² was applied to a polishing pad 2 made of Rodel-Nitta above; SUBA800, and the turntable 1 and the holder 5 were each placed at 100 r.
A polishing liquid is supplied from the supply pipe 3 to the polishing pad 2 at a rate of 12.5 ml / min while rotating in the opposite direction at a speed of pm, and the Cu film and the barrier layer deposited on the substrate are converted to the SiO ₂ film. Was polished until the surface was exposed. Here, as the polishing liquid, 2-quinolinecarboxylic acid 0.3 was used.
Wt%, hydrogen peroxide 16.7 wt%, average particle size 30 nm
Of pure water containing 1.3% by weight of γ-alumina particles and 4.0% by weight of colloidal silica, and having a weight ratio of hydrogen peroxide of about 56 times that of 2-quinolinecarboxylic acid. In the polishing step, the polishing liquid is C
No etching occurred at the time of contact with the u film, and the polishing rate at the time of polishing with the polishing pad was about 85 nm / min. For this reason, in the polishing step, the convex Cu film is polished preferentially from the surface that is in mechanical contact with the polishing pad, and the exposed barrier layer is polished, so-called etch back. As a result, the barrier layer remains in the trench and the embedded C is flush with the surface of the SiO ₂ film in the trench covered with the barrier layer.
A u wiring layer was formed.

After the weight of the polishing pad 2 by the holder 5 of the polishing apparatus is released and the rotation of the turntable 1 and the holder 5 is stopped, the Cu wiring layer is brought into contact with the polishing liquid. Was not dissolved (etched).

Example 3 First, a 1000-nm-thick Si film as an interlayer insulating film was formed on a silicon substrate having a diffusion layer such as a source and a drain formed on the surface by CVD.
After the O ₂ film is deposited, the SiO ₂ film has a depth of 500 corresponding to the wiring layer by a photo-etching technique.
A plurality of grooves of nm were formed. Then, a 15 nm thick T is deposited on the SiO ₂ film including the groove by sputtering.
A barrier layer made of iN and a Cu film having a thickness of 600 nm were deposited in this order.

Next, the substrate is held upside down on the substrate holder 5 of the polishing apparatus shown in FIG.
A load of 300 g / cm ² was applied to a polishing pad 2 made of Rodel-Nitta above; SUBA800, and the turntable 1 and the holder 5 were each placed at 100 r.
A polishing liquid is supplied from the supply pipe 3 to the polishing pad 2 at a rate of 12.5 ml / min while rotating in the opposite direction at a speed of pm, and the Cu film and the barrier layer deposited on the substrate are converted to the SiO ₂ film. Was polished until the surface was exposed. Here, as the polishing liquid, 2-quinolinecarboxylic acid 0.3 was used.
Wt%, hydrogen peroxide 16.7 wt%, average particle size 30 nm
Consisting of pure water containing 1.3% by weight of γ-alumina particles, 4.0% by weight of colloidal silica, and 10 mmol / l of sodium dodecyl sulfate as an anionic surfactant. Hydrogen peroxide having a ratio of about 56 times was used. In the polishing step,
The polishing liquid does not undergo any etching at the time of contact with the Cu film, and has a polishing rate of about 85 when polishing with the polishing pad.
nm / min. For this reason, in the polishing step, the convex Cu film is polished preferentially from the surface that is in mechanical contact with the polishing pad, and the exposed barrier layer is polished, so-called etch back. As a result, the barrier layer remained in the groove and a buried Cu wiring layer flush with the surface of the SiO ₂ film was formed in the groove covered with the barrier layer.

Since the polishing liquid having the above-mentioned composition containing a surfactant has a high polishing selectivity between Cu and SiO ₂ as shown in FIG.
It was possible to prevent the thinning of the _two films (interlayer insulating films).

Further, after the load on the polishing pad 2 by the holder 5 of the polishing apparatus is released and the rotation of the turntable 1 and the holder 5 is stopped,
Even when the Cu wiring layer was brought into contact with the polishing liquid, it was not dissolved (etched).

Next, the substrate after the formation of the buried wiring layer was subjected to ultrasonic cleaning using pure water. By performing such a cleaning treatment, Cu polishing pieces, Cu complex polishing pieces, and organic substances such as 2-quinoline carboxylic acid remaining on the surface of the SiO ₂ film (interlayer insulating film) and the like are removed.
The surface of the iO ₂ film could be cleaned.

Therefore, according to the third embodiment, the embedded C having the same thickness as the depth thereof is formed in the groove of the interlayer insulating film.
The u wiring layer could be formed flush with the surface of the interlayer insulating film, and the substrate surface after the formation of the wiring layer could be flattened. Further, after the Cu wiring layer is formed by an etch-back process using a polishing liquid having the above-mentioned composition containing a surfactant, ultrasonic cleaning is performed with pure water, whereby the interlayer is formed by the action of the surfactant in the polishing liquid. Since the surface of the insulating film was easily cleaned, a highly reliable semiconductor device having a buried Cu wiring layer having a low resistance inherent to Cu could be manufactured.

(Example 4) First, on a silicon substrate having a diffusion layer such as a source and a drain formed on the surface thereof, for example, a 1000 nm thick Si
After the O ₂ film is deposited, the SiO ₂ film has a depth of 500 corresponding to the wiring layer by a photo-etching technique.
A plurality of grooves of nm were formed. Then, a 15 nm thick T is deposited on the SiO ₂ film including the groove by sputtering.
A barrier layer made of iN and a Cu film having a thickness of 600 nm were deposited in this order.

Then, the substrate is held upside down on the substrate holder 5 of the polishing apparatus shown in FIG. 1 and the substrate is turned on the turntable 1 by the support shaft 4 of the holder 5.
A load of 300 g / cm ² was applied to a polishing pad 2 made of Rodel-Nitta above; SUBA800, and the turntable 1 and the holder 5 were each placed at 100 r.
A polishing liquid is supplied from the supply pipe 3 to the polishing pad 2 at a rate of 12.5 ml / min while rotating in the opposite direction at a speed of pm, and the Cu film and the barrier layer deposited on the substrate are converted to the SiO ₂ film. Was polished until the surface was exposed. Here, 2-pyridinecarboxylic acid 0.6 as the polishing liquid was used.
A pure water containing 1.4% by weight of γ-alumina particles having an average particle diameter of 30 nm and 4.1% by weight of colloidal silica was used. In the polishing step, the polishing liquid did not undergo any etching at the time of contact with the Cu film, and the polishing rate at the time of polishing with the polishing pad was about 30 nm / min. For this reason, in the polishing step, the convex Cu film is polished preferentially from the surface that is in mechanical contact with the polishing pad, and the exposed barrier layer is polished, so-called etch back. As a result, a barrier layer remained in the trench and a buried Cu wiring layer flush with the surface of the SiO ₂ film was formed in the trench covered with the barrier layer.

After the weight of the polishing pad 2 by the holder 5 of the polishing apparatus is released and the rotation of the turntable 1 and the holder 5 is stopped, the Cu wiring layer is brought into contact with the polishing liquid. Was not dissolved (etched).

(Example 5) First, as shown in FIG. 10A, an SiO ₂ film having a thickness of, for example, 800 nm is formed on a silicon substrate 21 having a diffusion layer such as a source and a drain (not shown) formed on the surface thereof by CVD. After depositing a film 22 and a Si ₃ N ₄ film 27 having a thickness of 200 nm as a polishing stopper film in this order to form an interlayer insulating film, a photo-etching technique is applied to the Si ₃ N ₄ film 27 and the SiO ₂ film 22. Thus, a plurality of grooves 23 having a shape corresponding to the wiring layer and having a depth of 500 nm were formed. Subsequently, as shown in FIG. 10B, a barrier layer 24 made of TiN having a thickness of 15 nm and a Cu film 25 having a thickness of 600 nm are formed on the Si ₃ N ₄ film 27 including the groove 23 by sputtering deposition. Deposited in order.

Next, the substrate 21 shown in FIG. 10B is held upside down on the substrate holder 5 of the polishing apparatus shown in FIG. 1, and the substrate is held by the support shaft 4 of the holder 5 by Rodel-Nitta. A 300 g / cm ² load was applied to the polishing pad 2 made of SUBA800, and the turntable 1 and the holder 5 were each placed at 100 r.
The polishing liquid is supplied from the supply pipe 3 to the polishing pad 2 at a rate of 12.5 ml / min while rotating in the opposite direction at a speed of pm to the Cu film 25 and the barrier layer 24 deposited on the substrate 21. Polishing was performed until the surface of the Si ₃ N ₄ film 27 was exposed. Here, 0.3% by weight of 2-quinoline carboxylic acid, 16.7% by weight of hydrogen peroxide, 1.3% by weight of γ-alumina particles having an average particle diameter of 30 nm and colloidal silica 4 having an average particle diameter of 30 nm were used as the polishing liquid. A pure water containing 0.0% by weight of which the amount of hydrogen peroxide was about 56 times as much as that of 2-quinolinecarboxylic acid was used. In the polishing step, the polishing liquid did not undergo any etching at the time of contact with the Cu film, and the polishing rate at the time of polishing with the polishing pad was about 100 nm / min. For this reason, the convex Cu film 25 shown in FIG. 10B is preferentially polished from the surface that is in mechanical contact with the polishing pad, and the exposed barrier layer 24 is polished. It has been made.

As a result, as shown in FIG. 10C, the barrier layer 24 remains in the groove 23 and the Si ₃ N _{4 is formed} in the groove 23 covered with the barrier layer 24.
A buried Cu wiring layer 26 flush with the surface of the film 27 was formed. Also, after the weight of the polishing pad 2 by the holder 5 of the polishing apparatus is released and the rotation of the turntable 1 and the holder 5 is stopped, the Cu wiring layer 26 is dissolved even if it comes into contact with the polishing liquid. (Etching) did not occur. Further, in the polishing step using the polishing liquid containing polishing abrasive grains, the interlayer insulating film is formed on the surface side by Si ₃ N ₄ functioning as a polishing stopper film.
Since the film 27 was formed, it was possible to prevent the film from being reduced in the etch-back step. Therefore, a semiconductor device provided with an interlayer insulating film having good withstand voltage can be manufactured.

(Embodiment 6) First, as shown in FIG. 11A, a p-type silicon substrate 32 having an n ⁺ -type diffusion layer 31 formed on the surface thereof is formed on a p-type silicon substrate 32 by a CVD method as a first interlayer insulating film. After depositing a SiO ₂ film 33 having a thickness of 1000 nm, a via hole 34 was formed in the SiO ₂ film 33 corresponding to the diffusion layer 31 by a photo-etching technique.
Subsequently, as shown in FIG. 11B, a barrier layer 35 made of TiN having a thickness of 20 nm is deposited on the SiO ₂ film 33 including the via hole 34 by sputter deposition. Cu film 36
Was deposited.

Next, the substrate 32 shown in FIG. 11B is held upside down in the holder 5 of the polishing apparatus shown in FIG. 1, and the substrate is manufactured by Rodel-Nitta by the support shaft 4 of the holder 5. Product name: A polishing pad 2 made of SUBA800 was given a load of 300 g / cm ² , and the turntable 1 and the holder 5 were each rotated at 100 rpm.
The polishing liquid is supplied from the supply pipe 3 at a speed of 12.5 ml / min while rotating the polishing pad 2 at a speed of 12.5 ml / min.
And the Cu film 36 and the barrier layer 35 deposited on the substrate 32 were polished until the surface of the SiO ₂ film 33 was exposed. Here, as the polishing liquid, 0.3% by weight of 2-quinolinecarboxylic acid, 16.7% by weight of hydrogen peroxide, 1.3% by weight of γ-alumina particles having an average particle diameter of 30 nm, and 4.0% by weight of colloidal silica, Pure water containing 10 mmol / l of sodium dodecyl sulfate, which is an anionic surfactant, was used in which the amount of hydrogen peroxide was about 56 times that of 2-quinolinecarboxylic acid by weight. In the polishing step, the polishing liquid did not undergo any etching at the time of contact with the Cu film, and the polishing rate at the time of polishing with the polishing pad was about 85 nm / min. For this reason, the convex Cu film 36 shown in FIG. 11B is polished preferentially from the surface that is in mechanical contact with the polishing pad, and the exposed barrier layer 35 is polished. It was done.

As a result, the barrier layer 35 remains in the via hole 34 as shown in FIG.
In the via hole 34 covered with the barrier layer 35, a via fill 37 made of Cu and flush with the surface of the SiO ₂ film 33 was formed. In addition, since the polishing liquid having the above-described composition containing a surfactant has high polishing selectivity between Cu and SiO ₂ as shown in FIG. 7, the film thickness of the SiO ₂ film (interlayer insulating film) is reduced in the etch back step. (Thinning) could be prevented. Further, after the weight of the polishing pad 2 by the holder 5 of the polishing apparatus is released and the rotation of the turntable 1 and the holder 5 is stopped, the etching proceeds even if the via-fill 37 comes into contact with the polishing liquid. I never did. Subsequently, the substrate after the formation of the via-fill 37 was subjected to ultrasonic cleaning using pure water to clean the surface of the SiO ₂ film 33.

Next, as shown in FIG. 12D, an Si ₃ N ₄ film 38 having a thickness of, for example, 800 nm as a second interlayer insulating film is deposited on the SiO ₂ film 33 including the via fill 37 by a CVD method. After that, the Si ₃ N ₄ film 38
Then, a plurality of grooves 39 having a shape corresponding to the wiring layer and having a depth of 400 nm were formed by photoetching. Further, a through hole 40 was formed in the groove 39 located on the via fill 37 by a photo-etching technique. Subsequently, as shown in FIG.
A Cu film 41 having a thickness of 900 nm was deposited on the Si ₃ N ₄ film 38 including the through holes 40 by sputter deposition.

Next, the substrate 32 shown in FIG. 12E is held upside down on the substrate holder 5 of the polishing apparatus shown in FIG. 1, and the substrate is held by the support shaft 4 of the holder 5 by Rodel-Nitta. A 300 g / cm ² load was applied to the polishing pad 2 made of SUBA800, and the turntable 1 and the holder 5 were each placed at 100 r.
A polishing liquid having a composition similar to that used in the above-described etch-back step is supplied to the polishing pad 2 at a rate of 12.5 ml / min from the supply pipe 3 while rotating in the opposite directions at a speed of pm. Cu film 41 deposited on the substrate 32
Was polished until the surface of the Si ₃ N ₄ film 38 was exposed.

As a result, the convex C shown in FIG.
The u film 41 is polished preferentially from the surface that is in mechanical contact with the polishing pad, so-called etch back is performed. By such an etch back, FIG.
As shown in FIG. 6, a buried Cu wiring layer 42 flush with the surface of the Si ₃ N ₄ film 38 was formed in the groove 39. At the same time, the via fill 37 passes through the through hole 40.
A buried Cu wiring layer 42 connected to was formed. After the weight of the polishing pad 2 by the holder 5 of the polishing apparatus is released and the rotation of the turntable 1 and the holder 5 is stopped, the Cu wiring layer 4 is removed.
Etching did not proceed even when No. 2 was brought into contact with the polishing liquid.

Therefore, according to the sixth embodiment, the first and second
The first interlayer insulating film 3
3 is formed with a via fill 37 which is flush with the surface thereof.
A semiconductor device having a multilayer wiring structure in which a Cu wiring layer 42 flush with the surface thereof was formed on the interlayer insulating film 39 and having a flattened surface could be manufactured.

[0085]

As described above, according to the present invention, Cu or the like is not dissolved at all when copper (Cu) or copper alloy (Cu alloy) is immersed, and the Cu or Cu alloy is removed during polishing. A polishing liquid for a copper-based metal that can be polished at a practical speed can be provided.

According to the present invention, at least one member selected from a groove and an opening is formed in an insulating film on a semiconductor substrate, and a wiring material film made of Cu or a Cu alloy deposited on the insulating film is formed. It is possible to provide a method of manufacturing a semiconductor device which can be etched back in a short time and, furthermore, has a buried wiring layer made of Cu or a Cu alloy formed in the insulating film so as to be flush with the surface of the insulating film.

Further, according to the present invention, at least one member selected from a groove and an opening is formed in an insulating film on a semiconductor substrate, and Cu or Cu deposited on the insulating film is formed.
The wiring material film made of an alloy can be etched back in a short time to form a buried wiring layer flush with the surface of the insulating film. And a method for manufacturing a semiconductor device having excellent withstand voltage can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a polishing apparatus used in a polishing step of the present invention.

FIG. 2 shows a polishing rate (processing rate) when a Cu film formed on a substrate is polished using a polishing liquid of the present invention and a conventional polishing liquid containing only polishing abrasive grains. FIG. 3 is a characteristic diagram shown in relation to temperature.

FIG. 3 is a characteristic diagram showing the relationship between the amount of 2-quinoline carboxylic acid and the polishing rate of a Cu film in a polishing liquid having a composition comprising 2-quinoline carboxylic acid, hydrogen peroxide, abrasive grains and water.

FIG. 4 is a characteristic diagram showing the relationship between the amount of hydrogen peroxide and the polishing rate of a Cu film in a polishing liquid having a composition comprising 2-quinolinecarboxylic acid, hydrogen peroxide, abrasive grains and water.

FIG. 5 is a cross-sectional view showing a state where a Cu film having irregularities is immersed in a polishing liquid having a composition comprising 2-quinoline carboxylic acid, hydrogen peroxide, polishing abrasive grains and water, and is polished using a polishing apparatus. FIG.

FIG. 6 is a characteristic diagram showing a polishing rate of a Cu film by a pH-adjusted polishing liquid of the present invention.

FIG. 7 shows a Cu film, a P-SiN film, and Si by a polishing liquid.
FIG. 4 is a characteristic diagram showing the relationship between the amount of a surfactant (sodium dodecyl sulfate) added and the polishing rate of each film in polishing of an O ₂ film.

FIG. 8 shows a Cu film, a P-SiN film and Si by a polishing liquid.
FIG. 4 is a characteristic diagram showing a relationship between a type of a surfactant to be added and a polishing rate of each film in polishing of an O ₂ film.

FIG. 9 is a sectional view showing a manufacturing step of the semiconductor device according to the first embodiment of the present invention.

FIG. 10 is a sectional view illustrating a manufacturing step of a semiconductor device according to a fifth embodiment of the present invention.

FIG. 11 is a sectional view illustrating a manufacturing step of a semiconductor device according to a sixth embodiment of the present invention.

FIG. 12 is a sectional view showing a manufacturing step of the semiconductor device in the sixth embodiment of the present invention.

[Explanation of symbols]

1 ... turntable 2 ... polishing pad, 3 ... supply pipe, 5 ... holder, 11,21,32 ... silicon substrate, 12,25,36,41 ... Cu film, 13 ... oxide layer, 22 and 33 ... SiO ₂ Films, 23, 39 ... grooves, 24, 35 ... barrier layers, 26, 42 ... Cu wiring layers, 37 ... via fills.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 21/304 622 H01L 21/3205

Claims (35)

(57) [Claims] 1. Copper containing a water-soluble organic acid, abrasive grains and water, which react with copper to form a copper complex which is hardly soluble in water and mechanically weaker than copper. Polishing liquid for base metals. 2. The polishing liquid according to claim 1, wherein the organic acid is 2-quinoline carboxylic acid. 3. The polishing liquid according to claim 1, wherein the organic acid is contained in the polishing liquid in an amount of 0.1% by weight or more. 4. The polishing abrasive grains are silica, zirconia,
At least one selected from cerium oxide and alumina
The polishing liquid for a copper-based metal according to claim 1, wherein the polishing liquid is made of two materials. 5. The polishing abrasive according to claim 1, wherein said polishing slurry contains 1 to 2 abrasive grains.
The polishing liquid for copper-based metals according to claim 1, which is contained in an amount of 0% by weight. 6. The polishing liquid according to claim 1, further comprising an oxidizing agent as a copper complex formation promoter. 7. The polishing liquid according to claim 6, wherein a content ratio of the oxidizing agent to the organic acid is 10 times or more by weight. 8. The polishing liquid for a copper-based metal according to claim 1, further comprising a surfactant. 9. The polishing liquid according to claim 8, wherein the surfactant is added to the polishing liquid in an amount of 1 mol / liter or more.
The polishing liquid for a copper-based metal as described above. 10. The method according to claim 1, further comprising a pH adjuster.
The polishing liquid for a copper-based metal according to claim 1, wherein 11. A step of forming at least one member selected from a groove and an opening corresponding to a shape of a wiring layer in an insulating film on a semiconductor substrate; and at least one member selected from the groove and an opening. Forming a wiring material film made of copper or a copper alloy on the insulating film, comprising: a water-soluble compound that reacts with copper to form a copper complex that is sparingly soluble in water and mechanically more brittle than copper. The wiring material film is polished by using a polishing liquid containing an organic acid, polishing abrasive grains and water until the surface of the insulating film is exposed, thereby embedding the wiring material film in the insulating film to form a wiring layer. And a method of manufacturing a semiconductor device. 12. The wiring material film is formed on the insulating film.
12. The method according to claim 11 , wherein a barrier layer is coated on the insulating film including at least one member selected from the groove and the opening before the formation. 13. The method according to claim 1, wherein the barrier layer comprises TiN, Ti, N
The method of manufacturing a semiconductor device according to claim 11 , wherein the semiconductor device is made of a material selected from b, W, and a CuTa alloy. 14. The copper alloy is a Cu—Si alloy, Cu
-Al alloy, Cu-Si-Al alloy, and Cu-Ag
The method according to claim 11 , wherein the material is selected from the group consisting of an alloy. The organic acid of 15. During the polishing liquid The method according to claim 11 semiconductor device, wherein the 2-quinolinecarboxylic acid. 16. The polishing composition according to claim 1, wherein the organic acid is contained in the polishing liquid in an amount of 0.1%.
The method of manufacturing a semiconductor device according to claim 11 , wherein the content of the semiconductor device is at least 10 wt%. 17. The abrasive grains in the polishing liquid, silica, zirconia, a method of manufacturing a semiconductor device according to claim 11, characterized in that it is made from at least one material selected from cerium oxide and alumina. 18. The polishing slurry according to claim 1, wherein
The method of manufacturing a semiconductor device according to claim 11 , wherein the content is 20% by weight. 19. The polishing liquid further comprises an oxidizing agent as a copper complex formation promoter.
12. The method for manufacturing a semiconductor device according to item 11 . 20. The method according to claim 19, wherein a content ratio of the oxidizing agent to the organic acid is 10 times or more by weight. The method according to claim 21, wherein the polishing liquid, a method of manufacturing a semiconductor device according to claim 11, characterized by further containing a surfactant. 22. The method according to claim 19, wherein the surfactant is contained in the polishing liquid.
The compound is added in an amount of at least mol / liter.
22. The method for manufacturing a semiconductor device according to item 21 . 23. The polishing liquid further comprises a pH adjuster.
12. The semiconductor device according to claim 11, comprising:
Manufacturing method of the device. 24. A semiconductor device comprising a semiconductor substrate having a diffusion layer formed thereon.
1 A groove corresponding to the shape of a wiring layer embedded in an insulating film
Selected from the first opening corresponding to the shape of one via fill
Forming at least one member, and forming on the first insulating film including an inner side surface and a bottom surface of the member.
Forming a barrier layer; and forming a barrier layer comprising copper or a copper alloy on the barrier layer including the member.
Forming a first wiring material film, which reacts with copper, is hardly soluble in water, and is more mechanically weaker than copper.
Water soluble organic acids, abrasive grains and water
The first wiring material film using the polishing liquid containing
The barrier layer is sequentially polished to fill the groove.
A first via hole in the first opening.
Forming one or both of the first and second buried wiring layers and the first via fill.
On the first insulating film including at least one wiring portion to be formed.
Forming a second insulating film; and forming a second insulating film having a bottom reaching the first via fill.
Forming two openings, and forming copper or copper alloy on the second insulating film including the second openings.
Forming a second wiring material film made of gold; reacting with copper to be hardly soluble in water and mechanically weaker than copper
Water soluble organic acids, abrasive grains and water
Polishing the second wiring material film using a polishing solution containing
Forming a second via fill in the second opening.
Forming a multi-layer wiring structure.
A method for manufacturing a semiconductor device having: 25. The barrier layer is made of TiN, Ti, N
made from a material selected from b, W or CuTa alloy
25. The multi-layer wiring structure according to claim 24, wherein
Semiconductor device manufacturing method. 26. The method according to claim 26, wherein the copper alloy is a Cu--Si alloy, Cu
-Al alloy, Cu-Si-Al alloy, and Cu-Ag
Characterized by being a material selected from the group consisting of alloys
25. A semiconductor device having a multilayer wiring structure according to claim 24.
Production method. 27. The organic acid in the polishing liquid,
25. The method according to claim 24, which is a norincarboxylic acid.
A method for manufacturing a semiconductor device having a multilayer wiring structure as described above. 28. The polishing composition according to claim 28, wherein the organic acid is contained in the polishing liquid in an amount of 0.1%.
25. The composition according to claim 24, wherein the content is at least 30% by weight.
A method for manufacturing a semiconductor device having a multilayer wiring structure. 29. The polishing abrasive in the polishing liquid,
Select from mosquito, zirconia, cerium oxide and alumina
Characterized by being made from at least one material
25. A semiconductor device having a multilayer wiring structure according to claim 24.
Production method. 30. The polishing slurry according to claim 1 , wherein
25. The composition according to claim 24, wherein the content is 20% by weight.
A method for manufacturing a semiconductor device having a multilayer wiring structure. 31. A copper complex is further formed in the polishing liquid.
An oxidizing agent is contained as a promoter.
24. A method for manufacturing a semiconductor device having a multilayer wiring structure according to item 24.
Law. 32. The oxidizing agent contained in the organic acid.
The ratio is at least 10 times by weight.
32. Manufacturing of a semiconductor device having a multilayer wiring structure according to claim 31.
Construction method. 33. The polishing liquid further comprises a surfactant.
25. The multilayer wiring according to claim 24, comprising:
A method for manufacturing a semiconductor device having a structure. 34. The polishing composition according to claim 34, wherein the surfactant is contained in the polishing liquid.
The compound is added in an amount of at least mol / liter.
35. A method for manufacturing a semiconductor device having a multilayer wiring structure according to 35.
Law. 35. The polishing liquid further comprises a pH adjuster.
25. The multilayer wiring according to claim 24, comprising:
A method for manufacturing a semiconductor device having a structure.