JP2002141314A - Slurry for chemical mechanical polishing and manufacturing method of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide CMP slurry which can realize low erosion and low scratching for CMP treatment of a conductive material film. SOLUTION: The CMP slurry contains polishing grain which comprises colloidal grain whose primary grain diameter is 5 to 30 nm and association degree is 5 or below.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
Slurry for Mechanical Polishing, especially DRA
The present invention relates to a slurry for CMP for forming a damascene wiring mainly composed of a metal such as Al, Cu, and W mounted on M or a high-speed logic LSI, and a method of manufacturing a semiconductor device using the same.

[0002]

2. Description of the Related Art In recent years, in semiconductor device manufacturing technology, LS
As the performance of I has become higher, the miniaturization, higher density, and multi-layering of wiring have been rapidly progressing. Not only are design rules being reduced, but new materials are being actively introduced. For example, as a wiring material, development of a material containing Cu as a main component and an interlayer insulating film (ILD) of a low dielectric constant type such as an organic type or a porous type is progressing.

In particular, when the CMP technique is applied to a dual damascene process in which wiring and connection wiring are buried in an insulating film, the number of steps can be reduced. In addition, since the CMP technique can reduce unevenness on the outermost surface of the wafer, a focus margin of a lithography process can be secured. Further, in the CMP technique, it is possible to form a wiring using a material such as Cu which is difficult to dry-etch.

In the current metal damascene wiring process,
A high polishing rate is desired to improve the throughput. In addition, in order to form high-performance wiring, metal parts such as wiring and low erosion (erase) such as interlayer insulating films are required.
o CMP) and a CMP process capable of achieving low scratches on metal parts such as wiring and interlayer insulating films. Here, erosion means metal loss due to dishing caused by overpolishing of wiring and the like in the CMP method and metal loss caused by thinning caused by overpolishing of an insulating film.

[0005] The CMP characteristics are mainly determined by the slurry and the polishing pad. The polishing pad needs some hardness to obtain low erosion. Currently, Rod
hard pads (IC1000-P
With a polishing pad softer than ad), it is difficult to control erosion even with a general slurry.

[0006] However, although the hard pad can achieve low erosion, there is a possibility that scratches due to coarse particles and excessive aggregates contained in the slurry or film peeling due to the scratch may occur. That is, at present, low erosion and low scratching are in a trade-off relationship. Therefore, it is necessary to improve the slurry side in order to realize both low erosion and low scratch.

The slurry for CMP has, for example, a composition in which abrasive particles are dispersed in water. Conventionally, silica or alumina formed by a fumed method has been used for the abrasive particles. The abrasive particles are inexpensive and have high purity. Further, it is considered that the particles formed by the fumed method form aggregates (secondary particles) in the production process, and this acts to increase the polishing rate.

[0008]

However, particles formed by the fumed method have a large variation in primary particle diameter, too large secondary particles, and easy formation of coarse particles. It becomes difficult to control.

An object of the present invention is to provide a slurry for CMP capable of achieving low erosion and low scratch upon CMP treatment of a conductive material film.

[0010] Another object of the present invention is to provide a conductive material film CM.
An object of the present invention is to provide a CMP slurry capable of achieving high-speed CMP, low erosion, and low scratch during P processing.

Still another object of the present invention is to provide a method of manufacturing a semiconductor device which enables formation of low erosion and low scratch wiring (for example, damascene wiring) embedded in a wiring groove of an insulating film. is there.

Still another object of the present invention is to provide a semiconductor device capable of forming a low erosion and low scratch wiring (eg, a damascene wiring) embedded in a wiring groove of an insulating film via a conductive barrier film. It is to provide a manufacturing method.

[0013]

According to the present invention, there is provided a slurry for CMP, comprising abrasive particles composed of colloidal particles having a primary particle diameter of 5 to 30 nm and an association degree of 5 or less.

Further, according to the present invention, the primary particle diameter is 5 to 2
0 nm first colloidal particles and a primary particle diameter of 20 nm
The first colloidal particles and the second colloidal particles of the same material, and wherein the ratio of the first colloidal particles to the total amount of the first and second colloidal particles is 0.6 to A slurry for CMP is provided, which contains abrasive particles of 0.9.

Further, according to the present invention, a step of forming a wiring groove on the surface of an insulating film formed on a semiconductor substrate; a step of depositing a conductive material film on the insulating film including the inside of the wiring groove; A slurry for chemical mechanical polishing containing abrasive particles composed of colloidal particles having a particle diameter of 5 to 30 nm and an association degree of 5 or less, or a first colloidal particle having a primary particle diameter of 5 to 20 nm, and a primary particle diameter exceeding 20 nm The first colloidal particles have the same size as the first colloidal particles and the second colloidal particles of the same material, and the weight ratio of the first colloidal particles to the total weight of the first and second colloidal particles is 0.1%.
A conductive material other than the conductive material film embedded in the wiring groove by subjecting the conductive material film to chemical mechanical polishing using at least a slurry for chemical mechanical polishing containing abrasive particles of 6 to 0.9; And a step of removing the film.

Further, according to the present invention, a step of forming a wiring groove on a surface of an insulating film formed on a semiconductor substrate, a step of depositing a conductive barrier film on the insulating film including an inner surface of the wiring groove, Depositing a wiring material film on the conductive barrier film so as to fill the wiring groove, and chemically and mechanically polishing the wiring material film to remove the conductive barrier film on the insulating film except for the inner surface of the wiring groove. A step of removing a wiring material film other than the wiring material film embedded in the wiring groove as a stopper; and a chemical machine including abrasive particles made of colloidal particles having a primary particle diameter of 5 to 30 nm and an association degree of 5 or less. A polishing slurry or a first colloidal particle having a primary particle diameter of 5 to 20 nm, and a second colloidal particle having a primary particle diameter exceeding 20 nm and the same material as the first colloidal particle, Said first, 0 the first colloidal particles occupying the total amount of the second colloidal particles by weight.
Chemical mechanical polishing a portion of the conductive barrier film on the insulating film using a slurry for chemical mechanical polishing containing abrasive particles of 6 to 0.9. Provided.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, C according to an embodiment of the present invention will be described.
The MP slurry will be described in detail.

(1) Slurry for CMP This slurry for CMP has a primary particle diameter of 5 to 30 nm.
It has a composition in which abrasive particles composed of colloidal particles having an association degree of 5 or less are dispersed in water, preferably pure water.

The colloidal particles include, for example, colloidal silica particles. The colloidal silica particles include, for example, Si (OC ₂ H ₅ ) ₄ , Si (s
_{ec-OC 4 H 9) 4} , Si (OCH 3) 4, Si (OC 4 H
₉ ) It can be obtained by hydrolyzing a silicon alkoxide compound such as ₄ by a sol-gel method. Such colloidal particles (eg, colloidal silica particles)
Has a very sharp particle size distribution as shown in FIG.

The primary particle size is determined by calculating a particle size cumulative curve showing the relationship between the particle size of colloidal particles and the cumulative frequency obtained by integrating the number of particles having the particle size. The curve has a cumulative frequency of 50%. Means the particle size. The particle size of the colloidal particles can be measured with an electron micrograph.

The primary particle size of the colloidal particles is specified for the following reasons. If the primary particle diameter of the colloidal particles is less than 5 nm, the polishing performance of a slurry containing the colloidal particles as abrasive particles may be reduced. The primary particle diameter of the colloidal particles is 3
If it exceeds 0 nm, erosion and scratches may occur during polishing with a slurry containing the colloidal particles as abrasive particles. More preferably, the primary particle diameter of the colloidal particles is 10 to 20 nm.

The degree of association means a value obtained by dividing the diameter of the secondary particles in which the primary particles are aggregated by the diameter of the primary particles (the diameter of the secondary particles / the diameter of the primary particles). Here, the degree of association of 1 means that only primary particles are monodispersed. The secondary particle diameter can be measured by a dynamic light scattering method, a laser diffraction method, or an electron microscope.

If the degree of association exceeds 5, erosion and scratching may occur during polishing with a slurry containing the colloidal particles having the degree of association as abrasive particles.

In the above colloidal particles, the diameter of the associated colloidal particles is preferably 100 nm or less.

The abrasive particles are contained in the slurry in an amount of 0.5 to 0.5.
Preferably, it is contained in an amount of 5% by weight. If the content of the abrasive particles is less than 0.5% by weight, the polishing performance of the slurry containing the abrasive particles may be reduced. If the content of the abrasive particles exceeds 5% by weight, erosion and scratches may occur during polishing with a slurry containing the abrasive particles. A more preferred amount of the abrasive particles is 0.5 to 2% by weight.

Further, by setting the upper limit of the abrasive particles (colloidal particles) contained in the slurry to 5% by weight, it is possible to prevent the primary particles of the colloidal particles from being excessively converted into secondary particles, and Can easily be controlled to 5 or less. As a result, low erosion and low scratching can be achieved during polishing with a slurry containing the abrasive particles.

It is desirable that the pH of the slurry for CMP is shifted by about ± 1 with respect to the isoelectric point of the colloidal particles, but basically, it may be used in a pH range of 0.5 to 12.

The slurry for CMP is allowed to further contain at least one component selected from 1) an oxidizing agent, 2) an oxidation inhibitor, and 3) a surfactant described below.

1) Oxidizing agent Examples of the oxidizing agent include ammonium persulfate, potassium persulfate, aqueous hydrogen peroxide, ferric nitrate, and cerium ammonium nitrate. This oxidizing agent
It is preferable to mix 0.1 to 5% by weight in the slurry.

2) Oxidation inhibitors The oxidation inhibitors include organic acids such as quinaldic acid, quinolinic acid, malonic acid, oxalic acid and succinic acid, and amino acids such as glycine, alanine and tryptophan. Among them, quinaldic acid,
Quinolic acid and glycine are preferred. The oxidation inhibitor,
It is preferable to mix 0.01 to 3% by weight in the slurry.

3) Surfactant This surfactant reduces erosion and scratches during polishing, and examples thereof include anionic surfactants, cationic surfactants, and nonionic surfactants. Of these, dodecylbenzene sulfonate, polyoxyethylene alkylamine, and polyoxyethylene lauryl ether are particularly preferred. This surfactant is preferably incorporated in the slurry in an amount of 0.01 to 1% by weight.

(2) CMP Slurry This CMP slurry is composed of first colloidal particles having a primary particle diameter of 5 to 20 nm, and a first colloidal particle having a primary particle diameter exceeding 20 nm and made of the same material as the first colloidal particles. 2 colloidal particles, and the ratio of the first colloidal particles (the total amount of the first colloidal particles / the first and second colloidal particles) to the total amount of the first and second colloidal particles is a weight ratio. Has a composition of 0.6 to 0.9 in water, preferably pure water.

Examples of the first and second colloidal particles include colloidal silica particles. The colloidal silica particles are, for example, Si (OC _{2
H 5) 4, Si (sec} -OC 4 H 9) 4, Si (OCH 3)
₄ , can be obtained by hydrolyzing a silicon alkoxide compound such as Si (OC ₄ H ₉ ) ₄ by a sol-gel method. Such first and second colloidal particles (for example, first and second colloidal silica particles) have a very sharp particle size distribution as shown in FIG. 3 described later.

The primary particle size of the first and second colloidal particles is determined by calculating a particle size cumulative curve showing the relationship between the particle size of the colloidal particles and the cumulative frequency obtained by integrating the number of particles having the particle size. Means the particle diameter at the point where the cumulative frequency of the particles is 50%. The particle size of the colloidal particles can be measured with an electron micrograph.

The first colloidal particles preferably have an association degree of 5 or less as defined in the slurry for CMP in (1).

The primary particle diameter of the second colloidal particles is:
In particular, it is desirable to have a size exceeding 20 nm and 50 nm or less.

The ratio (the total amount of the first colloidal particles / the total amount of the first and second colloidal particles) is 0.6 to
The reason for setting the value to 0.9 is as follows. If the ratio is less than 0.6, these first and second
Erosion and scratches may occur during polishing with a slurry containing the above colloidal particles as abrasive particles. On the other hand, if the ratio exceeds 0.9, the polishing performance of a slurry containing the first and second colloidal particles as abrasive particles may be reduced.

The abrasive particles are contained in the slurry in an amount of 0.5 to 0.5.
Preferably, it is contained in an amount of 5% by weight. If the content of the abrasive particles is less than 0.5% by weight, the polishing performance of the slurry containing the abrasive particles may be reduced. If the content of the abrasive particles exceeds 5% by weight, erosion and scratches may occur during polishing with a slurry containing the abrasive particles. A more preferred amount of the abrasive particles is 1 to 3% by weight. In particular, the second colloidal particles are preferably contained in the slurry at a maximum of 0.4% by weight.

It is desirable that the pH of the slurry for CMP is shifted by about ± 1 with respect to the isoelectric point of the first colloidal particles, but basically, it may be used in a pH range of 0.5 to 12.

In the CMP slurry, the first,
It is allowed to form abrasive particles by further blending the second colloidal particles with third particles made of a material different from these colloidal particles. As the third particles, for example, at least one particle selected from the group consisting of cerium oxide, manganese oxide, silica, alumina, and zirconia can be used. The third particles are particularly preferably colloidal alumina particles. The colloidal alumina particles, for example, _{Al (iso-OC 3 H 7} ) 3, Al (O
It can be obtained by hydrolyzing an aluminum alkoxide compound such as CH ₃ ) ₃ and Al (OC ₂ H ₅ ) ₃ by a sol-gel method.

The third particles preferably have a primary particle diameter of 5 to 30 nm based on the above definition. The third particles are preferably blended in an amount of 40% by weight or less based on the total amount of the first and second colloidal particles.

The slurry for CMP is allowed to further contain at least one component selected from 1) an oxidizing agent, 2) an oxidation inhibitor, and 3) a surfactant.

In order to polish a conductive material film formed on a substrate, for example, by the CMP slurry described above, a polishing apparatus shown in FIGS. 1 and 2 is used. FIG.
FIG. 2 is a sectional view showing a polishing apparatus used for the CMP process. FIG. 2 is a perspective view showing a main part of the polishing apparatus shown in FIG.

That is, the polishing plate receiver 23 is
It is arranged above via a bearing 22. Polishing machine 2
4 (turntable) is mounted on the polishing plate receiver 23. The polishing pad 25 is attached on the polishing board 24. The drive shaft 26 is connected to the central portions of the polishing disk receiver 23 and the polishing disk 24 for rotating the polishing disk receiver 23 and the polishing disk 24. This drive shaft 2
6 is rotated by a motor 27 via a rotating belt 28.

The substrate on which the conductive material film is formed, for example, the semiconductor wafer 20, is disposed at a position facing the polishing pad 25, and the suction cloth 30 and the suction cloth 30 attached to the suction plate (top ring) 31 by vacuum or water filling. It is fixed to the template 29. The top ring 31 is connected to a drive shaft 32. This drive shaft 3
2 is rotated by a motor 33 via two gears 34 and 35. The drive base 36 is fixed to the drive shaft 32. The cylinder 37 is attached to the drive base 36, and the drive base 36 moves up and down as the cylinder 37 moves up and down. The slurry supply pipe 38 is led out of a slurry tank (not shown), and has a lower end disposed above the polishing pad 25.

In such a polishing apparatus, the polishing board 24 on which the polishing pad 25 is adhered is rotated by driving the motor 27. The semiconductor wafer 20 is fixed to the top ring 31, the motor 33 is driven to rotate the top ring 31 in the same direction as the polishing pad 25, and the top ring 31 is rotated by the cylinder 37.
The semiconductor wafer 20 attached to the polishing pad 2
Press on 5. At this time, a slurry tank (not shown)
Are rotated in the same direction through a slurry supply pipe 38, and are dropped between the polishing pad 25 and the semiconductor wafer 20 which are in sliding contact with each other, and the conductivity of the wafer surface (the back surface in FIGS. 1 and 2) is reduced. Polishing of a conductive material film.

Next, a method for manufacturing a semiconductor device according to an embodiment of the present invention will be described in detail.

(First Step) A wiring groove is formed on the surface of an insulating film on a semiconductor substrate, and a conductive material film is formed on the entire surface including the wiring groove.

As the insulating film, for example, an inorganic insulating film such as a silicon oxide film formed using a silane-based gas or a TEOS-based gas, a low-dielectric-constant insulating film containing fluorine, an organic-based film, or a porous film A low-K insulating film that is soft, brittle, easily peeled, and hydrophobic like a film can be used.

The conductive material film may be a metal wiring material film alone or a laminated film of two or more layers of a conductive barrier film and a metal wiring material film laminated on the barrier film. .

As the wiring material film made of the metal, for example, Cu or Cu—Si alloy, Cu—Al alloy, Cu
Cu alloys such as -Si-Al alloys, Cu-Ag alloys,
Al or an Al alloy, W, or the like can be used.

As the conductive barrier film, for example, Ti
N, Ti, Nb, W, WN, TaN, TaSiN, T
It is made of one layer or two or more layers selected from a, V, Mo, Zr and ZrN.

(Second Step) The conductive material film on the substrate is subjected to a CMP process using the polishing apparatus shown in FIGS. 1 and 2 and the CMP slurry (1) or (2), and the wiring is formed. An embedded wiring (damascene wiring) is formed in the insulating film by removing a conductive material film other than the conductive material film embedded in the groove.

When the conductive material film is composed of two or more laminated films of a conductive barrier film and a wiring material film made of a metal laminated on this barrier film, the wiring material film is formed as shown in FIG. Then, after performing the CMP processing using the polishing apparatus shown in FIG. 2 and the CMP slurry of the above (1) and (2), the exposed conductive barrier film portion located on the surface of the insulating film is used as the wiring material film. By performing CMP treatment using a CMP slurry having a composition different from that of the used slurry and removing the same, a damascene wiring buried in the insulating film via the conductive barrier film can be formed.

In the case where the polishing apparatus is composed of two or more laminated films of a conductive barrier film and a wiring material film made of a metal laminated on the barrier film, the polishing apparatus shown in FIGS. The CMP process is performed using a CMP slurry containing the first and second colloidal particles described above in (3) and the third particles such as colloidal alumina particles to remove the laminated film, whereby the conductive film is formed on the insulating film. The damascene wiring buried through the conductive barrier film can be formed.

Next, another method of manufacturing a semiconductor device according to the embodiment of the present invention will be described.

(First Step) A wiring groove is formed on the surface of an insulating film formed on a semiconductor substrate, and a conductive barrier film is deposited on the insulating film including the inner surface of the wiring groove. A wiring material film made of metal is deposited on the film so that the wiring grooves are filled.

The insulating film, the conductive barrier film and the wiring material film may be the same as those described above.

(Second step) The wiring material film is subjected to chemical mechanical polishing, and the wiring material film embedded in the wiring groove using the conductive barrier film on the insulating film excluding the inner surface of the wiring groove as a stopper. The wiring material film other than the above is removed.

The chemical mechanical polishing treatment can be performed using a general-purpose CMP slurry.

(Third Step) The conductive barrier film portion on the insulating film is subjected to CM using the polishing apparatus shown in FIGS. 1 and 2 and the CMP slurry (1) and (2).
A P process is performed to form a damascene wiring buried through the conductive barrier film.

The CM according to the embodiment of the present invention described above
The slurry for P has a composition including abrasive particles composed of colloidal particles having a primary particle diameter of 5 to 30 nm and a degree of association of 5 or less. Therefore, during CMP treatment of a conductive material film, for example, a Cu film, low erosion and low erosion Scratching can be achieved.

Further, another CMP according to the embodiment of the present invention
The slurry for use includes first colloidal particles having a primary particle diameter of 5 to 20 nm, and second colloidal particles having a primary particle diameter exceeding 20 nm and the same material as the first colloidal particles, and The weight ratio of the first colloidal particles to the total amount of the second colloidal particles is 0.6 to 0.5%.
Since the abrasive particles of No. 9 are contained, it is possible to increase the speed of CMP and to reduce the erosion and the scratch in the CMP treatment of the conductive material film, for example, the Cu film.

That is, FIG. 3 is a graph showing logarithmic normal plots of primary particles of silica particles formed by the fumed method and colloidal silica particles formed by the sol-gel method. In FIG. 3, the vertical axis represents the cumulative frequency (%), and the horizontal axis represents the particle diameter (nm). The cumulative frequency curve A of the colloidal silica particles has a particle diameter of 15 nm (1σ; 11.8%) at a point of 50% cumulative frequency, and the cumulative frequency curve B of the colloidal silica particles has a particle diameter of 50% cumulative point. Is 41 nm (1σ; 12.9)
%), And the cumulative frequency curve C of the fumed silica particles has a particle size of 58 nm (1
σ; 25.2%).

As shown in FIG. 3, the colloidal silica particles have a smaller variation in particle diameter than the fumed method.
Further, the colloidal silica particles hardly aggregate to form coarse particles. For this reason, the colloidal silica particles are easy to handle from the viewpoint of controlling the particle size.

However, when the primary particle diameter of the colloidal particles is as small as about 10 nm as shown in FIG. 4 described below, erosion and scratch hardly occur, but the polishing rate decreases. On the other hand, when the colloidal particles become large particles having a primary particle diameter of more than 30 nm, particularly large particles of more than 50 nm, the polishing rate is improved, but erosion and scratching tend to occur.

That is, FIG. 4 shows a change in the polishing rate (CuRR) of Cu and a change in erosion size (n
m). In FIG. 4, the polishing speed (nm / min) is on the left vertical axis, and the magnitude of erosion (n
m), and the horizontal axis represents the particle diameter (nm) of the colloidal silica particles. Curve D in FIG. 4 is a characteristic line showing the magnitude of erosion with a change in the particle size of the colloidal silica particles, and curve E is a characteristic line showing the magnitude of the polishing rate of Cu with a change in the particle size of the colloidal silica particles. Line.

The colloidal particles have a property that it is difficult to form aggregates, that is, secondary particles. The colloidal particles exhibit low erosion and low scratching properties when the primary particle diameter is small, and have a high polishing rate when the primary particle diameter is large. It has the characteristics of

From the above, according to the embodiment of the present invention, the conductive material film is formed by using a composition including abrasive particles composed of colloidal particles having a primary particle diameter of 5 to 30 nm and an association degree of 5 or less. For example, it is possible to provide a CMP slurry capable of performing a CMP process while achieving low erosion and low scratch on a Cu film.

According to the embodiment of the present invention, the first colloidal particles having a primary particle diameter of 5 to 20 nm and the second colloidal particles having a primary particle diameter exceeding 20 nm and made of the same material as the first colloidal particles are used. Particles, and wherein the first colloidal particles occupy the total amount of the first and second colloidal particles in the composition containing abrasive particles having a weight ratio of 0.6 to 0.9, thereby providing a conductive material. It is possible to provide a CMP slurry capable of performing a high-speed CMP process while achieving low erosion and low scratch on a conductive material film, for example, a Cu film.

Further, according to the embodiment of the present invention, a wiring groove is formed on the surface of the insulating film on the semiconductor substrate, and a conductive material film is formed on the entire surface including the wiring groove. CM using the polishing apparatus shown in FIGS. 1 and 2 and the CMP slurries (1) and (2) described above.
By performing a P process to remove a conductive material film other than the conductive material film embedded in the wiring groove, a low erosion and low scratch embedded wiring (damascene wiring) is formed in the wiring groove of the insulating film. Can be formed.

Further, according to the embodiment of the present invention, a wiring groove is formed on the surface of the insulating film on the semiconductor substrate, a conductive barrier film is deposited on the entire surface including the inner surface of the wiring groove, and a wiring material film made of metal is further formed. After this, the wiring material film is subjected to CMP using the conductive barrier film as a stopper, and the exposed conductive barrier film portion is continuously exposed, for example, as shown in FIG.
Polishing apparatus shown in FIG. 2 and (1) and (2)
By performing the CMP process using the CMP slurry described above, a low erosion and low scratch wiring (damascene wiring) embedded in the wiring groove of the insulating film via a conductive barrier film can be formed.

In particular, a soft, brittle, easily peelable, hydrophobic Low-K film such as an organic film or a porous film.
When a damascene wiring is formed by embedding a conductive barrier film in a wiring groove of an insulating film via a conductive barrier film, the CMP of the above (1) and (2)
The CMP process using the slurry for use is soft and gentle with respect to the Low-K insulating film. For this reason, the Low
When the conductive barrier film on the -K insulating film is subjected to the CMP treatment, the Low-K insulating film is not peeled off together with the conductive barrier film, but is buried in the wiring groove of the insulating film via the conductive barrier film. The embedded low erosion and low scratch wiring (damascene wiring) can be formed. As a result, it is possible to manufacture a semiconductor device having a high-speed damascene wiring in which propagation delay caused by a low dielectric constant insulating film is suppressed.

[0074]

Embodiments of the present invention will be described below with reference to the drawings.

(Example 1) First, as shown in FIG. 5A, an insulating film 102 made of, for example, silicon oxide is formed on a silicon substrate (silicon wafer) 101 on which, for example, semiconductor elements are formed. The surface was flattened. Subsequently, the insulating film 102 is selectively etched to a depth of 4
A wiring groove 103 having a thickness of 00 nm was formed. Subsequently, a TaN film 104 as a barrier film having a thickness of about 10 nm was deposited on the insulating film 102 and on the inner surface of the wiring groove 103. Thereafter, a Cu film 105 having a thickness of 800 nm was sequentially deposited by a sputtering method and a plating method.

Next, the surface of the Cu film 105 is subjected to the CMP treatment under the following conditions using the polishing apparatus shown in FIGS. 1 and 2 and the first CMP slurry having the following composition, as shown in FIG. So that the wiring groove 103
Only the Cu film 105 was left. The CMP process could be stopped at the TaN film 104.

<Composition of the slurry for the first CMP> Abrasive particles: The first having a primary particle diameter of 15 nm and an association degree of 3.0.
Colloidal silica (colloidal silica particles A in FIG. 3 described above): 0.8 wt%, second colloidal silica having a primary particle diameter of 41 nm and a degree of association of 3.0 (colloidal silica particles B in FIG. 3 described above): 0.2 wt% -Ammonium persulfate (oxidizing agent): 1 wt%-Quinaldic acid (oxidation inhibitor): 0.5 wt%-Potassium dodecylbenzenesulfonate: 0.06 wt
%; PH: 9.2 (adjusted by adding aqueous potassium hydroxide solution).

<CMP treatment conditions> Polishing pad; trade name IC1000 / S manufactured by Rodel
UBA400, • Slurry supply flow rate: 200 cc / min, • Top ring (TR) rotation speed: 100 rpm, • Turntable (TT) rotation speed: 100 rpm, • Load (DF): 300 g / cm ² .

Next, the exposed portion of the TaN film 104 located on the insulating film 102 was subjected to the CMP treatment under the following conditions using the polishing apparatus shown in FIGS. 1 and 2 and the second CMP slurry having the following composition. By this CMP process, a Cu wiring (Cu damascene wiring) 106 buried in the wiring groove 103 via the TaN film 104 was formed as shown in FIG. 5C.

<Composition of Slurry for Second CMP> Abrasive particles: Colloidal silica having a primary particle diameter of 30 nm:
3 wt%, ethylenediamine: 0.05 wt%.

<CMP Treatment Conditions> Slurry supply flow rate: 200 cc / min. Polishing pad; trade name IC1000 / S manufactured by Rodel.
UBA400, rotation speed of top ring (TR): 50 rpm, rotation speed of turntable (TT): 50 rpm, load (DF): 300 g / cm ² .

In the first embodiment, the CMP of the Cu film
FIG. 6 shows the CMP characteristics by the processing. In FIG. 6, except for using fumed silica particles as abrasive particles,
A CMP slurry having the same composition as in Example 1 and a Cu film formed on the Cu film under the same conditions using the polishing apparatus shown in FIGS.
The CMP characteristics after the MP treatment are shown as Comparative Example 1.
The vertical axis in FIG. 6 is erosion / wiring width 10
The value represents a size (nm) of 0 μm, and the horizontal axis represents overpolishing (%). The erosion here indicates a size when the wiring width is 100 μm and overpolishing is performed in a range of +0 to 100%. In other words, the erosion represents the size when the overpolishing is performed by adding a polishing time of 0 to 100% to the polishing time until the just polishing in which the Cu film other than the inside of the wiring groove disappears.

As is apparent from FIG. 6, according to Comparative Example 1 in which fumed silica particles were used as the abrasive particles, the erosion was 400 nm (wiring width 100 μm, +
100% over polish). The polishing rate of the Cu film according to Comparative Example 1 was 432 nm / min.

On the other hand, the primary particles having a primary particle diameter of 1
5 nm primary colloidal silica particles and primary particle size 4
Example 1C containing 1 nm second colloidal silica particles
In the CMP process using the slurry for MP, the polishing rate of the Cu film is increased by about 20% to 520 nm / min, and erosion is reduced by 2%.
It was dramatically improved to 8 nm (wiring width 100 μm, + 100% over polish).

The mixing balance between the first colloidal silica particles and the second colloidal silica particles in the slurry used in Example 1 has a relationship shown in FIG. In FIG. 7, the left vertical axis indicates the polishing rate of Cu (CuRR: nm / m).
in), the right side of the vertical axis represents the size of erosion (nm), and the horizontal axis represents the ratio (weight ratio) of the first colloidal silica to the total amount of the first and second colloidal silica particles. Curve F represents a characteristic curve representing the magnitude of erosion, and curve G represents a characteristic curve representing the Cu polishing rate.

As is clear from FIG. 7, a low erosion and a high polishing rate can both be achieved when the ratio of the first colloidal silica to the total amount of the first and second colloidal silica particles is in the range of 0.6 to 0.9. I understand.

The ratio of the first colloidal silica to the total amount of the first and second colloidal silica particles is from 0.6 to 0.6.
In the range of 0.9, the Cu film can be polished at a high speed while the polishing rate of the TaN film 104 is suppressed, and the selectivity of these films can be increased. For example, the polishing rate of the TaN film 104 can be reduced to 1/5 (about 3 nm / min) of that of the Cu film. As a result, the TaN film 104 is more reliably
Can function as a polishing stopper.

As described above, according to the first embodiment, it is possible to achieve an improvement in throughput due to an increase in the polishing rate for Cu, and the formation of a high-performance Cu damascene wiring with greatly improved erosion.

The slurry for CMP used in the first embodiment also has a small friction during polishing (current value of the torque sensor of the table motor), which is advantageous for peeling of the insulating film. Further, by mixing the two types of colloidal silica particles, the uniformity of the polishing rate within the wafer surface is improved, and particularly, the polishing rate at the wafer edge is improved.
The short-circuit yield of the wiring was 80 to 9 in Comparative Example 1.
It was improved from 0% to 100%.

Embodiment 2 First, as shown in FIG. 8A, an insulating film 202 is formed on a silicon substrate (silicon wafer) 201 on which, for example, semiconductor elements are formed.
This insulating film 202 is selectively etched to a depth of 400
A wiring groove 203 of nm was formed. The insulating film 202
It is a soft, brittle, and easily peelable low-K film such as a porous film or an organic film. Subsequently, an Nb film 204 as a barrier film having a thickness of about 15 nm was deposited on the insulating film 202 and on the inner surface of the wiring groove 203. Thereafter, an 800 nm-thick Al film 205 was deposited by a sputtering method.

Next, the surface of the Al film 205 is subjected to the CMP treatment under the following conditions using the polishing apparatus shown in FIGS. 1 and 2 and the first CMP slurry having the following composition, as shown in FIG. So that the wiring groove 203
Only the Al film 205 was left. In polishing the Al film 205, the Nb film 204 functions as a stopper. Therefore, even if a slurry containing mixed particles of alumina and silica formed by the fumed method as described below is used, the above-described damage to the fragile insulating film 202 can be suppressed.

<Composition of slurry for first CMP> Abrasive particles; mixed particles of alumina and silica formed by fumed method; ammonium persulfate (oxidizing agent): 0.5 wt%; quinaldic acid (oxidation inhibitor): 0 .02 wt%, <CMP treatment conditions> Slurry supply flow rate: 200 cc / min. Polishing pad: Brand name IC1000 / S manufactured by Rodel.
UBA400, rotation speed of top ring (TR): 100 rpm, rotation speed of turntable (TT): 100 rpm, load (DF): 300 g / cm ² .

Next, the exposed portion of the Nb film 204 located on the insulating film 202 was subjected to a CMP process using the polishing apparatus shown in FIGS. 1 and 2 and the second CMP slurry having the following composition under the following conditions. By this CMP process, the Nb film 20 is formed in the wiring groove 203 as shown in FIG.
Al wiring (Al damascene wiring) 2 buried through 4
06 was formed.

<Composition of the slurry for the second CMP> Abrasive particles; colloidal silica having a primary particle diameter of 15 nm and an association degree of 3.0: 0.8 wt%; ammonium persulfate (oxidizing agent): 1 wt%; quinaldic acid ( Oxidation inhibitor): 0.05 wt% Cationic surfactant: 0.025 wt%

<CMP treatment conditions> Polishing pad; trade name, Polite, manufactured by Polytex
x, the supply flow rate of the slurry: 200 cc / min, the number of revolutions of the top ring (TR): 60 rpm, the number of revolutions of the turntable (TT): 100 rpm, and the load (DF): 300 g / cm ² .

In the CMP treatment of the Nb film 204, the soft, brittle, and hydrophobic low-K insulating film 202 can be polished without damaging it, and the damascene wiring 206 can be formed.

FIG. 9 shows the relationship between the primary particle diameter of the colloidal silica in the slurry used in Example 2 and the scratch on the insulating film. The degree of association of colloidal silica was kept constant at 3.0. In FIG. 9, the vertical axis is 8
The number of scratches (pieces) on the insulating film on the inch wafer is shown, and the horizontal axis represents the primary particle diameter (nm) of colloidal silica contained in the slurry.

As is clear from FIG. 9, the primary particle diameter is 30
It can be seen that the number of scratches on the low-K insulating film sharply increases when CMP is performed with a slurry containing colloidal silica particles having a size exceeding nm as abrasive particles.

On the other hand, when the slurry of this embodiment containing colloidal silica particles having a primary particle diameter of 5 to 30 nm as abrasive particles is subjected to the CMP treatment, the number of scratches on the low-K insulating film can be drastically reduced to almost zero. .

As described above, according to the second embodiment, a soft, brittle, and easily peelable low like an organic insulating film or a porous insulating film.
The CMP process can be performed without damaging the −K film. Therefore, when damascene wiring is formed in multiple layers, the upper layer film peels due to scratches in each layer, current shortage due to metal remaining at the time of wiring formation, abnormal pattern shape due to focus shift in the lithography process, etc. Can be improved.

(Example 3) A Cu film deposited on an insulating film made of, for example, silicon oxide on a silicon substrate (silicon wafer) on which a semiconductor element and the like are formed is subjected to the polishing apparatus shown in FIGS. Example 1 except that CMP was performed using the CMP slurry having the composition under the following conditions.
A Cu wiring (Cu damascene wiring) buried in the wiring groove via the TaN film was formed in the same manner as described above to manufacture a semiconductor device.

<Composition of CMP slurry> Abrasive particles: Colloidal silica particles having a primary particle diameter of 25 nm having different association degrees: 1.0 wt%, ammonium persulfate (oxidizing agent): 1 wt%, quinaldic acid (oxidizing inhibitor) ): 0.5 wt%, potassium dodecylbenzenesulfonate: 0.06 wt
%; PH: 9.2 (adjusted by adding aqueous potassium hydroxide solution).

<CMP Processing Conditions> Polishing pad; trade name IC1000 / S manufactured by Rodel
UBA400, • Slurry supply flow rate: 200 cc / min, • Top ring (TR) rotation speed: 100 rpm, • Turntable (TT) rotation speed: 100 rpm, • Load (DF): 300 g / cm ² .

FIG. 10 shows the relationship between the Cu polishing rate (CuRR :) and the erosion with respect to the degree of association of the colloidal silica particles which are the abrasive particles in the slurry for CMP used in Example 3. In FIG. 10, the left vertical axis represents the polishing rate (nm / min) of Cu, the right vertical axis represents the size of erosion (nm), and the horizontal axis represents the degree of association of the colloidal particles contained in the slurry. Curve H represents a characteristic curve representing the Cu polishing rate with a change in the degree of association, and curve I represents a characteristic curve representing the magnitude of erosion with a change in the degree of association.

As is clear from FIG. 10, the erosion shifts to a direction in which the erosion deteriorates as the degree of association of the colloidal silica particles in the slurry increases. Further, when the degree of association of the colloidal silica particles exceeds 5, the Cu film and T
It was confirmed that many fine scratches were generated on the aN film.

On the other hand, the slurry of the present embodiment containing colloidal silica particles having an association degree of 5 or less
It can be seen that when the MP treatment is performed, the erosion on the surface of the Cu film can be suppressed although the polishing rate is reduced.

For example, when a slurry containing colloidal silica particles having an association degree of 3 and a primary particle diameter of 25 nm is used, the erosion of the slurry of Comparative Example 1 containing fumed silica particles as the above-mentioned abrasive particles was 116 nm (see FIG. 6). Erosion can be reduced to 68 nm.

As described above, according to the third embodiment, the polishing rate of a metal film such as Cu can be improved, and the erosion can be greatly improved. For example, Cu damascene wiring can be easily formed.

Embodiment 4 First, as shown in FIG. 11A, an insulating film 302 made of, for example, silicon oxide is formed on a silicon substrate (silicon wafer) 301 on which, for example, semiconductor elements are formed. The surface was flattened. Subsequently, the insulating film 302 was selectively etched to form a wiring groove 303 having a depth of 400 nm. Continued,
A TiN film 304 as a barrier film having a thickness of about 15 nm was deposited on the insulating film 302 and on the inner surface of the wiring groove 303. Thereafter, the W film 305 having a thickness of 600 nm is
Deposited by D method.

Next, the W film 305 and the TiN film 304 are successively formed under the following conditions using the polishing apparatus shown in FIGS. 1 and 2 and a slurry for CMP having the following composition.
MP treated. As a result of this CMP processing, a W wiring (W damascene wiring) 306 buried in the wiring groove 303 via the TiN film 304 was formed as shown in FIG.

<Composition of slurry for CMP> Abrasive particles: primary particles having a primary particle diameter of 15 nm and an association degree of 3.0
Colloidal silica particles: 2.5 wt%, primary particle diameter 41
Second colloidal silica particles having an association degree of 3.0 nm: 0.
3 wt%, colloidal alumina particles having a primary particle diameter of 15 nm and a degree of association of 1.5: 0.2 wt%, ferric nitrate (oxidizing agent): 5 wt%, ammonium persulfate (oxidizing agent): 0.5 wt%, Malonic acid (oxidation inhibitor): 1 wt%, pH: 1.5.

<CMP Processing Conditions> Polishing pad; trade name IC1000 / S manufactured by Rodel
UBA400, • Slurry supply flow rate: 200 cc / min, • Top ring (TR) rotation speed: 100 rpm, • Turntable (TT) rotation speed: 100 rpm, • Load (DF): 300 g / cm ² , • Polishing time: 160 seconds.

According to the fourth embodiment, the erosion (wiring width: 5 μm, + 50% over polish) is 30 n
The erosion was improved as compared with the case of using the slurry of Comparative Example 1 containing fumed silica particles as the above-mentioned abrasive particles (polishing time: 210 seconds, erosion: 180 nm).

The slurry for CMP containing the first and second colloidal silica particles used as the abrasive particles in the first embodiment was used for the CMP of the barrier film such as the Nb film in the second embodiment.
Even when applied to the treatment, similarly to the second embodiment, damage is applied to a soft, brittle, and easily peelable low-K film such as an organic insulating film or a porous insulating film which is a base film of the Nb film. The CMP process can be performed without giving.

[0115]

As described above, according to the present invention, it is possible to provide a slurry for CMP which can achieve low erosion and low scratch in the CMP treatment of the conductive material film.

According to the present invention, the conductive material film CM
In the P treatment, it is possible to provide a CMP slurry capable of achieving high-speed CMP, low erosion, and low scratch.

Further, according to the present invention, it is possible to provide a method of manufacturing a semiconductor device which enables formation of low erosion and low scratch wiring (for example, damascene wiring) embedded in a wiring groove of an insulating film.

Further, according to the present invention, a method of manufacturing a semiconductor device capable of forming low erosion and low scratch wiring (eg, damascene wiring) embedded in a wiring groove of an insulating film via a conductive barrier film. Can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a polishing apparatus used for a CMP process.

FIG. 2 is a perspective view showing a main part of the polishing apparatus of FIG. 1;

FIG. 3 is a graph showing the dispersion of colloidal particles and fumed particles contained in a slurry for CMP.

FIG. 4 is a graph showing a relationship between a colloidal particle diameter contained in a slurry for CMP, a Cu polishing rate (CuRR), and erosion.

FIG. 5 is a sectional view showing a manufacturing step of the semiconductor device according to the first embodiment of the present invention.

FIG. 6 is a graph showing a relationship (CMP characteristics) between the degree of erosion and overpolishing by the CMP processing in Example 1 and Comparative Example 1.

FIG. 7 is a diagram showing the balance between the first and second colloidal silica particles and the Cu polishing rate (Cu polishing rate) in the CMP treatment of Example 1.
9 is a graph showing the relationship between (RR) and erosion.

FIG. 8 is a sectional view showing a manufacturing step of the semiconductor device according to the second embodiment of the present invention.

FIG. 9 is a graph for explaining the relationship between the colloidal particle diameter and the number of scratches in the CMP process of Example 2.

FIG. 10 is a graph showing the relationship between the degree of association of colloidal particles contained in the CMP slurry of Example 3 and Cu polishing rate (CuRR) and erosion.

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

[Explanation of symbols]

 Reference Signs List 20: semiconductor wafer, 21: stage, 24: polishing disk, 25: polishing pad, 31: suction disk (top ring), 38: slurry supply pipe, 101, 201, 301: silicon substrate, 102, 202, 302: insulation Films, 103, 203, 303: wiring groove, 104: TaN film, 105: Cu film, 106, 206, 306: wiring, 204: Nb film, 205: Al film, 304: TiN film, 305: W film.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/3205 H01L 21/88 KMR (72) Inventor Nobuyuki Kurashima Shinsugita-machi, Isogo-ku, Yokohama-shi, Kanagawa No. 8 In the Toshiba Yokohama office of the Company Limited (72) Inventor Hiroyuki Yano 8 in Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture In the Yokohama office of the Toshiba Corporation (72) Inventor Nobuo Kawabashi 2-11-24 Tsukiji, Chuo-ku, Tokyo No. Within JSR Co., Ltd. (72) Masayuki Hattori Inventor, Masayuki Hattori 2-1-1-24 Tsukiji, Chuo-ku, Tokyo Inside JSR Co., Ltd. (72) Kazuo Nishimoto 2-11-24, Tsukiji, Chuo-ku, Tokyo JSR Co., Ltd. F term in the company (reference) 3C058 AA07 CB01 CB10 DA02 DA12 DA17 5F033 HH08 HH09 HH11 HH12 HH17 HH18 HH19 HH20 HH21 HH27 HH 32 HH33 HH34 MM01 MM12 MM13 PP15 PP27 QQ09 QQ48 QQ49 QQ50 RR04 RR11 RR21 RR29 SS04 WW01 WW04 XX00 XX01

Claims (21)

[Claims] 1. A slurry for chemical mechanical polishing comprising abrasive particles composed of colloidal particles having a primary particle diameter of 5 to 30 nm and an association degree of 5 or less. 2. The slurry for chemical mechanical polishing according to claim 1, wherein the colloidal particles are colloidal silica particles. 3. The slurry for chemical mechanical polishing according to claim 1, wherein when the colloidal particles are associated, the associated secondary particles have a particle size of 100 nm or less. 4. The method according to claim 1, wherein the abrasive particles comprise 0.5
The slurry for chemical mechanical polishing according to claim 1, which is contained in an amount of 5 to 5% by weight. 5. A first colloidal particle having a primary particle diameter of 5 to 20 nm, a primary colloidal particle having a primary particle diameter exceeding 20 nm,
The first colloidal particles include the first colloidal particles and the second colloidal particles of the same material, and the weight ratio of the first colloidal particles to the total amount of the first and second colloidal particles is 0.6 to
A slurry for chemical mechanical polishing, comprising abrasive particles having a particle diameter of 0.9. 6. The slurry for chemical mechanical polishing according to claim 5, wherein the first and second colloidal particles are colloidal silica particles. 7. The slurry for chemical mechanical polishing according to claim 5, wherein the abrasive particles further include third particles made of a material different from the first and second colloidal particles. 8. The slurry according to claim 7, wherein the third particles are colloidal alumina particles. 9. The method according to claim 9, wherein the abrasive particles comprise 0.5
The slurry for chemical mechanical polishing according to claim 5, which is contained in an amount of 5 to 5% by weight. 10. The slurry for chemical mechanical polishing according to claim 1, further comprising an oxidizing agent and an oxidation inhibitor. 11. The slurry for chemical mechanical polishing according to claim 10, wherein the oxidation inhibitor is at least one selected from quinaldic acid, quinolinic acid, and glycine. 12. The slurry for chemical mechanical polishing according to claim 1, further comprising a surfactant. 13. The slurry for chemical mechanical polishing according to claim 12, wherein the surfactant is dodecylbenzene sulfonate. 14. A step of forming a wiring groove on the surface of an insulating film formed on a semiconductor substrate; a step of depositing a conductive material film on the insulating film including the inside of the wiring groove; ３０30 nm, the degree of association is a slurry for chemical mechanical polishing containing abrasive particles composed of colloidal particles of 5 or less, or the primary colloidal particles having a primary particle diameter of 5 to 20 nm, and the primary particle diameter is greater than 20 nm, The first colloidal particles include the first colloidal particles and the second colloidal particles of the same material, and the weight ratio of the first colloidal particles to the total amount of the first and second colloidal particles is 0.6 to 0.
The conductive material film is chemically and mechanically polished using at least a slurry for chemical mechanical polishing containing abrasive particles of No. 9 to remove a conductive material film other than the conductive material film embedded in the wiring groove. And a method of manufacturing a semiconductor device. 15. The method according to claim 14, wherein the conductive material film is a wiring material film. 16. The method according to claim 15, wherein the wiring material film is a copper film. 17. The method according to claim 17, wherein the conductive material film includes TiN, Ti,
Nb, W, WN, TaN, TaSiN, Ta, V, M
The wiring material film is formed by using the chemical mechanical polishing slurry with two or more layers of at least one conductive barrier film selected from o, Zr and ZrN and a wiring material film laminated on the barrier film. The method for manufacturing a semiconductor device according to claim 14, wherein chemical mechanical polishing is performed. 18. The method according to claim 18, wherein the conductive material film includes TiN, Ti,
Nb, W, WN, TaN, TaSiN, Ta, V, M
o, Zr, and ZrN, two or more stacked films of at least one conductive barrier film selected from the group consisting of at least one conductive barrier film and a wiring material film stacked on the barrier film.
Chemical mechanical polishing is performed using a chemical mechanical polishing slurry further including third particles made of a material different from the second colloidal particles to remove a conductive material film other than the conductive material film embedded in the wiring groove. The method for manufacturing a semiconductor device according to claim 14, wherein: 19. A step of forming a wiring groove on a surface of an insulating film formed on a semiconductor substrate; a step of depositing a conductive barrier film on the insulating film including an inner surface of the wiring groove; Depositing a wiring material film on the film so as to fill the wiring groove; and chemically and mechanically polishing the wiring material film, and using the conductive barrier film on the insulating film excluding the inner surface of the wiring groove as a stopper to form the wiring A step of removing a wiring material film other than the wiring material film embedded in the groove and a slurry for chemical mechanical polishing comprising abrasive particles composed of colloidal particles having a primary particle diameter of 5 to 30 nm and an association degree of 5 or less; Or the primary particle size is 5-20 nm
And a second colloidal particle having a primary particle size of more than 20 nm and the same material as the first colloidal particle.
A slurry for chemical mechanical polishing, comprising abrasive particles comprising colloidal particles, and wherein the first colloidal particles occupy 0.6 to 0.9 by weight in the total amount of the first and second colloidal particles. Subjecting the conductive barrier film portion on the insulating film to chemical mechanical polishing using the method. 20. The method according to claim 19, wherein the insulating film is a porous film or an organic film having a lower dielectric constant than SiO ₂ . 21. The conductive barrier film is made of TiN, T
i, Nb, W, WN, TaN, TaSiN, Ta, V,
20. The method of manufacturing a semiconductor device according to claim 19, wherein the semiconductor device is made of one or more layers selected from Mo, Zr, and ZrN.