JP2002158194A - Slurry for chemical mechanical polishing and method of manufacturing semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a C capable of performing a process that does not significantly lower a polishing rate even after long polishing and does not damage an insulating film.
An MP method is provided. SOLUTION: At least one kind of fluorine organic compound is added to a slurry having a solvent and abrasive particles dispersed in the solvent, and C is added to the surface to be polished on the surface of a semiconductor substrate such as a wafer.
Perform MP processing. Al, C as abrasive particles in slurry
Oxides, carbides or nitrides containing u, Si or the like as main components, or mixtures or mixed crystals thereof are used. The fluorine organic compound contains a surfactant, a reagent having a surface active action, a reagent having a hydrophobic portion and a hydrophilic portion, a fluorinating agent, and the like. The film to be polished is a metal film, a laminated film thereof, or a film of a material selected from alloys, nitrides, borides, and oxides thereof. Friction between the polishing surface and the polishing pad is small, so that scratches on the polishing surface can be reduced and peeling can be reduced. The Cu scraping speed is also constant over time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor substrate mounted on a DRAM or a high-speed logic LSI.
The present invention relates to a slurry for chemical mechanical polishing (CMP) for forming a damascene wiring such as the above, and a method for manufacturing a semiconductor device using the slurry.

[0002]

2. Description of the Related Art In recent years, in semiconductor device manufacturing technology, LS
With the increase in performance of I, finer wiring, higher density, and multi-layered wiring are rapidly progressing. Not only are design rules shrinking, but new materials are being actively introduced. For example, as a wiring material, development of a material containing Cu as a main component, an interlayer insulating film of a low dielectric constant such as an organic or porous material, and the like are progressing. In particular, when the CMP technique is applied to a dual damascene process in which a wiring or a connection wiring is buried in an insulating film, the number of steps can be reduced, and the focus margin of the lithography process can be secured by reducing unevenness on the outermost surface of the wafer. You can also. In addition, the CMP technique is an indispensable important technique because 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,
High polishing rate is desired to improve throughput,
Further, in order to form a high-performance wiring, low erosion (Erosio) such as a metal part of a wiring or an interlayer insulating film is required.
n) There is a demand for a CMP process that can achieve low scratches on metal parts such as wiring and interlayer insulating films. C
In the MP method, metal loss due to dishing caused by overpolishing of wiring and the like and metal loss due to thinning caused by overpolishing of an insulating film easily occur. These are collectively referred to as erosion. C
The inventors consider that the MP characteristics are mainly determined by the slurry and the polishing pad. The polishing pad needs some hardness to obtain low erosion.
Hard Pad (I) currently marketed by Rodel
It is considered that it is difficult to control erosion with a material softer than C1000-Pad) using any slurry. However, although the hard Pad can achieve low erosion, it is difficult to eliminate coarse particles contained in the slurry, scratches due to excessive agglomerates or film peeling due to scratches, and therefore, at present, low erosion and low scratch Has a trade-off relationship.

[0004] Therefore, in order to realize both low erosion and low scratch, it is necessary to improve the slurry side so that no scratch occurs even when the hard pad is used. In general, when designing a slurry, it is necessary to pay attention to the surface state of the polished surface, in particular, an altered layer or a protective film formed on the surface and abrasive particles for polishing the surface. The deteriorated layer or the protective film is formed from a metal oxide, a complex compound, or the like. However, these materials have a high polishing rate, a low erosion, and a scratch on the metal portion having a surface on which the protective film is formed. Is an important factor. When forming a damascene wiring, care must be taken for the interlayer insulating film. That is, low polishing rate, low erosion, and low scratch are desirable.

[0005]

As described above, CMP is an essential process in the field of manufacturing semiconductor devices such as current LSIs. In particular, in the process of forming wiring, the conventional RIE (Reactive Ion Ething) process is indispensable for the next generation LSI such as extremely difficult processing of Cu and processing of a metal having a thickness of 1 μm or more, particularly aluminum (Al). Wiring structures cannot be formed. In order to solve these problems, research and development of a damascene wiring process for embedding wiring in an interlayer insulating film using CMP is rapidly progressing. The problem of the current CMP technology is to achieve both a high polishing rate and low erosion, which are in a trade-off relationship, and the present invention solves this problem. In the conventional semiconductor device manufacturing technology, in the processing of a material such as Cu or Ti, which is difficult to solve by the RIE (Reactive Ion Etching) process, the wiring yield cannot be secured. In the case of RIE, the smaller the wiring space becomes, the harder it becomes to cut, and the uncut portion is left, resulting in a short wiring. In response to the demand for reducing the number of processes to reduce manufacturing costs, R
The IE has a problem that it is difficult to reduce the number of steps because it is stacked one by one to form a multilayer, such as flattening of an insulating film and formation of a via hole.

In order to solve these problems, at present, C
Research and development of a buried wiring (damascene wiring) process using MP is being rapidly promoted. The main problems of current CMP using metal as a film to be polished, that is, metal CMP, are (1) improvement of polishing rate, (2) suppression of erosion, (3) reduction of defects, and (4) CMP characteristics of slurry. And stabilization of the dispersed state of the abrasive particles. (1)
Is necessary to improve throughput. In particular, when polishing a metal having a thickness of more than 1 μm,
The polishing rate is time dependent. Generally, the polishing rate tends to decrease with time. With a film thickness of 2 μm in about 3 minutes,
It is ideal if it can be performed by the first step process.
In the case (2), it is necessary to reduce the value and variation of the wiring resistance in a situation where even the formation of the wiring is becoming difficult. In particular, since the operating speed of the LSI is limited by the RC delay of the wiring, it is necessary to prevent an increase in wiring resistance due to metal loss caused by erosion. (3)
(4) relates to wiring reliability and yield. (4) In order to reduce the process cost, if the stable characteristics can be maintained for a long period of time, the slurry need not be frequently replaced, so that the slurry cost can be suppressed.

As one of means for solving these series of problems, there is a method of adding a surfactant to a slurry.
However, in the prior art surfactants having an alkyl group in the hydrophobic part, (1) and (2), (3), and (4) have a trade-off relationship and stabilize without deteriorating the CMP characteristics. It is difficult to achieve, and it has not yet been put to practical use. It is considered that this is largely due to the surfactant activity of the alkyl group. On the other hand, a material containing Ti, Ta, V, Nb or the like as a main component is used for a liner or a barrier metal of a Cu or Al damascene wiring. These are HF
Since it is insoluble in acids other than the above, there is no suitable reactant for CMP. Therefore, it is a chemical-poor mechanical-based CMP. Normally, peeling is likely to occur if the film that is difficult to scrape is continuously scraped. Since Ta and the like are hard to cut and are hard materials, when they are peeled off, they will severely damage the polished surface. Further, HF is difficult to handle, and silica as abrasive particles is dissolved. Alumina does not melt, but it is not practical because there is a problem that the polishing rate of a low dielectric constant insulating film (Low-K film), which is indispensable for next-generation multilayer wiring, is too high. The present invention has been made in view of such circumstances, and provides a CMP method capable of performing processing without significantly lowering the polishing rate even after long polishing and without damaging the insulating film.

[0008]

According to the present invention, there is provided a polishing method for a surface of a semiconductor substrate such as a wafer by adding at least one kind of fluorine organic compound to a slurry having a solvent and abrasive particles dispersed in the solvent. Is subjected to a CMP process. The slurry contains Al, Cu, S as abrasive particles.
Oxides, carbides and nitrides containing at least one of i, Cr, Ti, C and Fe as a main component, or a mixture or a mixed crystal thereof can be used. The fluorine organic compound contains a surfactant, a reagent having a surface active action, a reagent having a hydrophobic portion and a hydrophilic portion, a fluorinating agent, and the like. The insulating film is an inorganic insulating film formed by using a silane-based gas or a TEOS-based gas, or an insulating film mainly composed of SiO ₂ containing fluorine (F) for the purpose of lowering the dielectric constant. Soft and brittle, like membranes and organic porous membranes
Even a Low-K film having a dielectric constant ε (relative dielectric constant) of 3 or less that is easily peeled and has hydrophobicity is hardly damaged. The film to be polished is Cu, Al, W,
Of a film made of a material selected from Ti, Mo, Nb, Ta, V, Ru, and Ag or a laminated film thereof, or a material selected from an alloy, a nitride, a boride, and an oxide containing these as a main component It is a membrane. Friction between the polishing surface and the polishing pad is small, so that scratches on the polishing surface can be reduced and peeling can be reduced.

That is, the slurry for chemical mechanical polishing of the present invention is characterized by comprising a solvent, abrasive particles dispersed in the solvent, and at least one kind of fluorine organic compound. The fluorine organic compound may have a fluoromethyl group or a perfluoroalkyl group as a hydrophobic group in the molecule. The fluorine organic compound may contain fluorine used for electrophilic fluorination. The fluorine organic compound is a perfluoroalkylbedine, a perfluoroalkylethylene oxide adduct,
Perfluoroalkyl oligomer, perfluoroalkyl carboxylate, perfluoroalkyl quaternary ammonium salt, fluorobenzene intermediate, benzenetrifluoride intermediate, aliphatic intermediate, N-fluoropyridinium salt, N-fluoropyrrolidone, N- Fluoro-N-
Alkyl-arene sulfonamide, FCIO ₃ , CF
_At least one of ₃ COOF and CH ₃ COOF may be used. The fluorine organic compound may include any of an alkyl group, an aromatic ring, and a heteroaromatic ring. The fluorine organic compound may have at least one of an anion, a cation, a nonionic or an amphoteric as a functional group. The concentration of the fluorine organic compound may be 0.001 wt% to 0.5 wt%.

As the abrasive particles, Al, Cu, Si,
It may be an oxide, carbide or nitride containing at least one element selected from Cr, Ce, Ti, C and Fe as a main component, or a mixture or mixed crystal thereof. The oxidizing agent may further include at least one selected from ammonium persulfate, potassium persulfate, aqueous hydrogen peroxide, ferric nitrate, and ceric ammonium nitrate. As additives, quinaldic acid, quinolinic acid, nicotinic acid, picolinic acid, malonic acid, oxalic acid,
It may contain at least one of succinic acid, glycine, alanine and tryptophan. The method of manufacturing a semiconductor device according to the present invention includes a step of forming a wiring groove on a surface of an insulating film formed on a semiconductor substrate; a step of depositing a metal film on the insulating film including the inside of the wiring groove; Removing the metal film other than the metal film embedded in the wiring groove by subjecting the film surface to chemical mechanical polishing using the above slurry.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. First, a first embodiment will be described with reference to FIG. The present invention could not be obtained by using a surfactant having an alkyl group by adding a surfactant having a fluoroalkyl group in a hydrophobic part to a slurry for chemical mechanical polishing. (1) Polishing rate Improvement, (2) suppression of erosion, (3) reduction of polishing defects,
(4) The CMP characteristics of the slurry and the dispersion state can be stabilized. Surfactants having a fluoroalkyl group exhibit higher surface-active properties than alkyl groups and exhibit their effects in small amounts. In this embodiment, a liner and a Cu film are laminated on an insulating film having a wiring groove formed on a semiconductor substrate. Cu is polished using the liner as a stopper (first step), and then unnecessary portions of the liner are removed. (2nd step) The CMP process is performed in a two-step process. Then, Cu is polished (Cu
Touch-up) In the first step, a perfluoroalkylethylene oxide nonionic surfactant is added to the CMP slurry to achieve a stable process. The fluorine organic compound contains a surfactant, a reagent having a surface active action and containing a hydrophilic part and a hydrophobic part, or a fluorinating agent.

FIG. 1 is a manufacturing process sectional view for explaining the formation of a Cu dual damascene wiring. First, a semiconductor substrate 100 made of silicon or the like on which a semiconductor element (not shown) is formed.
An insulating film 101 made of a silicon oxide film or the like is formed thereon. A wiring groove 104 having a depth of 600 nm where a wiring is formed and a contact hole 1 having a depth of 500 nm for making contact with the semiconductor substrate 100 are formed on the surface of the insulating film 101.
05 is opened in the bottom surface of the wiring groove 104. Next, a TaN liner 102 is deposited by sputtering to a thickness of about 200 nm, a Cu film 103 is deposited to a thickness of about 1200 nm by a seed layer by sputtering, and the remainder is deposited by plating (FIG. 1A). Wiring groove 104 and contact hole 105
Are embedded with a TaN liner 102 and a Cu film 103. Next, unnecessary portions of the Cu film 103 are removed by a CMP process (FIG. 1B). In the first step, the TaN liner 101 is stopped.

[0013] Here, a conventional slurry is used, and ammonium persulfate (1 wt%) as an oxidizing agent, quinaldic acid (0.5 wt%) as an oxidation inhibitor, and alumina (0.5 wt) as polishing particles are added to the slurry. And the pH of the slurry is controlled at 9.2 with an aqueous solution of potassium hydroxide. Using this controlled slurry, slurry flow: 200 cc, IC1000 /
SUBA400 (trade name of Rodale), load (D
F): 300 g / cm ² , top ring (TR) rotation speed: 100 rpm, turntable (TT) rotation speed: 1
The CMP process is performed for 200 seconds under the condition of 00 rpm. Next, using the slurry containing the fluorine organic compound of the present invention, Ta was used.
Touch-up for removing unnecessary parts of N liner 102 (2
nd step) (FIG. 1C). Since this touch-up is a finishing process of wiring, it completely removes unnecessary metal, removes scratches on wiring and insulating film, particles on wiring and insulating film, and acids that induce corrosion. It is a difficult process that must be done.

First, it is necessary to polish the Cu film 103 / TaN liner / insulating film 101 and a different material in a well-balanced manner. Since TaN is excellent in chemical resistance, it enhances mechanical polishing power more than chemical. In this case, the abrasive particle concentration is set higher. That is, about 5 wt% is generally used. This is achieved, but as the abrasive particle concentration increases, the abrasive particles tend to agglomerate in the supply tank. Furthermore, if there are acids, ions, etc. in the slurry,
Agglomeration is accelerated by the salting-out effect, and the abrasive particles tend to harden, so that a state in which the abrasive particles do not redisperse (hard cake) is likely to occur. However, since the polishing is performed with the slurry in which the coarse particles are mixed, not only the scratches but also the scratches are made. And is not achieved. Further, when the hard cake is formed, the concentration of the abrasive particles in the slurry contributing to the polishing decreases, so that the rate balance is lost and the polishing itself cannot be performed. The addition of a surfactant is effective in preventing the aggregation of particles and the formation of a hard cake. However, when a conventional alkyl group is contained, the effect is reduced unless it is added at a high concentration. If the dispersion effect is to be enhanced, there is a problem that the polishing rate balance is lost and polishing cannot be performed. The addition of a surfactant is also very effective. That is, the surfactant is the key in touch-up.

When a surfactant having a fluoroalkyl group, which is a fluorine-based organic compound of the present invention, is used in a slurry, the dispersion effect can be improved with a small amount compared to the conventional surfactant having an alkyl group, so that a desired polishing rate balance can be achieved. Can be kept. FIG. 2 is a characteristic diagram illustrating the effect of adding a surfactant to the slurry of the present invention. FIG. 2 (a) shows the results when CMP is performed using a conventional surfactant having an alkyl chain using the slurry. FIG. 2B is a characteristic diagram when CMP is performed using a slurry to which the fluorine compound of the present invention is added. The Cu polishing rate-surfactant concentration curve (-■-) and the number of coarse particles-surfactant curve (-
◆-) is shown. The horizontal axis is the surfactant concentration (wt
%), And the vertical axis represents the Cu polishing rate (nm / min) and the number of coarse particles (particles / ml). When the polishing rate of Cu is 200 mn / min or more, the number of coarse particles (tertiary particle diameter:
A surfactant concentration satisfying the condition of preventing Cu corrosion (1 μm or more) of 5000 particles / ml does not exist in the conventional case, but can be used in a wide range of 0.001 to 0.5 wt% in the present invention.

For example, hydrogen peroxide: 1 wt.
%, Quinolinic acid: 0.1 wt%, silica as abrasive particles: 3 wt% in a solvent such as pure water, and 0.025 wt% of a perfluoroalkylethylene oxide-based surfactant (nonion) added to the slurry for CMP. And using this, slurry flow: 200 cc / mi
n, polishing pad: Polytex (trade name of Rodale), DF: 300 g / cm ² , TR rotation speed: 52 rpm, TT rotation speed: 50 rpm
The CMP process was performed for 0 seconds. As a result, unnecessary metal could be completely removed. As a result, the wiring width 0.2 μm
The yield of wiring with a length of 10 m and a length of 10 m is 100%. (1) is achieved, defects (scratch, remaining particles) are less than 10 pieces / wafer, and (2) and (3) are also achieved. Was.
Of course, residual particles have also been completely removed. No corrosion of Cu was observed. In addition, the process was able to be performed stably for two weeks. This is because the surfactant stably dispersed the abrasive particles and prevented hard cake formation. Furthermore, the effect of suppressing erosion small has been confirmed. In this embodiment, erosion was performed at a wiring width of 50 μm and a wiring coverage of 80% at 40 nm.
Was suppressed. In the prior art, it was 85 nm.

When a surfactant having an alkyl group according to the prior art is used, it is difficult to maintain a polishing rate balance and prevent agglomeration of abrasive particles. However, according to the present invention, such a problem could be solved by adding 0.001 wt% or more of the fluorine-based organic compound.
In this embodiment, a fluorine-based nonionic (nonionic) surfactant has been described as the fluorine-based organic compound. However, a fluorine-based surfactant having a hydrophilic portion having the same potential as the potential of the abrasive particles may be used. Similar effects can be obtained.

Next, a second embodiment will be described with reference to FIGS. FIG. 4 is a cross-sectional view showing a manufacturing process for explaining formation of a Cu damascene wiring. In this embodiment, the Cu thick film is C
A Cu damascene wiring in which a stable process is achieved is formed by using a slurry to which a perfluorooligomer is added during MP. Although there is a process of polishing Cu having a thickness of 1 μm or more in a manufacturing process of a semiconductor device such as an LSI,
The problem is that the polishing rate decreases (see FIG. 3). FIG.
Is a characteristic diagram showing the relationship between the polishing time in the CMP process and the amount of Cu scraping. The horizontal axis represents the polishing time (second), and the vertical axis represents the C time.
u represents the shaved amount (nm). The solid line is the CMP of the present invention.
This is a characteristic line showing characteristics, and the dotted line is a characteristic line showing conventional CMP characteristics. For example, for polishing for 60 seconds, 500 nm
It can be cut, but if it is polished for 120 seconds at a stretch, only 800 nm can be cut. The shaving amount for 60 to 120 seconds is reduced to 300 nm. It is considered that this is because reactants and slurry components (mainly abrasive particles) generated during polishing adhere to the polishing pad to cause mess. Therefore, each of them requires an appropriate hydrophilic treatment.

Further, lowering the dielectric constant of an organic system (Low-K)
When a Cu damascene wiring is formed using an insulating film made of a material, attention must be paid to defects and peeling more than when an inorganic insulating film is handled. In addition, the organic insulating film is often hydrophobic. When the surface of the semiconductor substrate is hydrophobic, there is also a problem that particles easily adhere. Therefore, the point is to make the insulating film surface, the reaction product, the slurry component, and the polishing pad surface hydrophilic. Next, a process flow when performing CMP on a Cu film having a film thickness will be described with reference to FIG. First, an insulating film 201 such as a silicon oxide film is formed on a semiconductor substrate 200 such as silicon. A wiring groove 204 having a depth of 800 nm is formed on the surface of the insulating film 201 by patterning. Here, the insulating film 201 is an organic insulating film, and is a soft, brittle, and easily peelable film. Further, the insulating film 201 itself is hydrophobic. Then, TaN
10 nm for the liner 202 and 1400 n for the Cu film 203
m are sequentially deposited. As for the Cu film 203, a seed layer is formed by a sputtering method, and the rest is formed by plating (FIG. 4A).

Next, the Cu film 203 and the TaN liner 20
Unnecessary parts other than the part embedded in the second wiring groove 204 are removed by the CMP process (FIG. 4B). In this embodiment, a one-step process for completing polishing by the CMP method at one time is used. The slurry components were: oxidizing agent: ammonium persulfate (1 wt%), oxidation inhibitor: quinaldic acid (0.5 wt%), abrasive particles: colloidal silica (1
wt%), alanine (0.3 wt%), a modifier and the like are added to a solvent such as pure water, and a perfluorooligomer (0.025 wt%) is used as a surfactant which is a fluorine-based organic compound.
And the pH is controlled at 9 with an aqueous solution of potassium hydroxide. And slurry flow: 200cc / mi
n, polishing pad: IC1000 / SUBA400, D
F: 300 g / cm ² , TR rotation speed: 100 rpm, T
The CMP process was performed for 150 seconds under the condition of T rotation speed: 100 rpm. In the present invention, unnecessary metal on the entire surface of the wafer can be polished by the CMP process for 150 seconds. However, when a conventional surfactant having an alkyl group was used, unnecessary metals could not be completely removed even after 300 seconds of CMP (see FIG. 3).

The reason that the metal could not be completely removed by the conventional technique is that the reaction product and the polishing pad surface were insufficiently hydrophilized, so that the polishing pad surface was left with shavings and the state in which the polishing pad was likely to be clogged. This is considered to be due to the fact that the surfactant is accumulated on the polishing pad, and the surfactant concentration apparently increases during polishing. When the surface of the polishing pad is made hydrophilic or the hydrophobic material is made hydrophilic, particularly when the material is electrically neutral, electric attraction does not work. Is positively (+) charged) is smoothly discharged from the polished surface. In the present invention,
As for defects and scratches, soft, brittle and easily peelable films like organic insulating films and porous insulating films are not damaged, and friction during polishing (torque sensor current value of table motor) Is small, it is presumed that this is also an advantageous direction for peeling. Further, the surfactant can be expected to have an effect of preventing corrosion of Cu because it protects oxidized Cu, but the effect was also confirmed by adding 0.001 wt% or more of the fluorine-based organic compound of the present invention. .

Here, when the fluorine-based organic compound is added in an amount of 0.5 wt% or more, the easiness of shaving of the surface protective film appears, and the polishing rate is significantly reduced. The cause is considered to be that the ratio of the surfactant in the protective film increases.
Therefore, it is desirable that the concentration of the surfactant used is 0.5 wt% or less. In this example, a fluorine-based nonionic (nonionic) surfactant was described as the fluorine-based organic compound. However, the same applies to the case where a fluorine-based surfactant having a hydrophilic portion having the same potential as the potential of the abrasive particles is used. The effect of is obtained.

Next, a third embodiment will be described. In this embodiment, a method of polishing TaN using a fluorinating agent will be described. Then, similarly to the first embodiment, the present invention is applied to a touch-up process for forming a Cu damascene wiring. As described in the prior art, CMP utilizing Ta's chemical power
Is difficult because it is inert. However, it is extremely active only for fluorine. The inventor paid attention to this fluorine. That is, the present invention aims at fluorination of TaN. Fluoropyridine is used as the fluorinating agent. Fluoropyridine is an organic compound suitable for the case where Cu and Ta coexist in order to protect the Cu surface after pyridine is adsorbed on Cu after F is dissociated by fluorination of Ta. The slurry component is fluoropyridine (0.2wt
%) And silica (0.5 wt%) dissolved in an ethylene chloride solvent. The polishing conditions were as follows: slurry flow: 20
0 cc / min, polishing pad: IC1000 / SUBA
400, DF: 300 g / cm ² , TR rotation speed: 100
rpm, TT rotation speed: C for 45 seconds under the condition of 100 rpm
MP processing was performed.

[0024] This eliminates the need for mechanically rich CMP mainly using abrasive particles, so that the concentration of abrasive particles can be reduced. This is an advantageous direction from the viewpoint of scratch and peel resistance. Further, in the prior art, at the time of touch-up, it was necessary to perform polishing with a soft pad having large friction in order to avoid scratches due to coarse particles and improve mechanical efficiency. However, since a slurry having a low concentration of abrasive particles is used according to the present invention, a hard pad can be used, which is a great advantage from the viewpoint of suppressing erosion.

Next, a fourth embodiment will be described with reference to FIG. FIG. 5 is a manufacturing process sectional view for explaining the formation of an Al damascene wiring. In this example, a method of performing Al CMP using a compound having a fluoromethyl group on a pyridine ring and a sulfonic acid as a functional group will be described. The role of the fluorine-based organic compound is to form a protective film on the Al surface and fix the abrasive particles to the polishing pad (that is, anchor effect) by utilizing the hydrophobicity of the fluoromethyl group and the hydrophilicity of the sulfonic acid. Things. The anchor effect refers to improving polishing efficiency (polishing speed) by fixing polishing particles to a polishing pad. First, an insulating film 30 such as a silicon oxide film is formed on a semiconductor substrate 300 such as silicon.
Form one. The surface of the insulating film 301 has a depth of 300 nm.
The wiring groove 304 is patterned. Here, the insulating film 3
01 is a soft, brittle and easily peelable film such as an organic film. Next, the Nb liner 302 is
An l film 303 is deposited by sputtering to a thickness of about 800 nm (FIG. 5A).

Next, unnecessary portions of the Al film 303 and the Nb liner 302 are polished and removed by CMP at a stretch. The slurry component of the present invention used in this example includes an oxidizing agent: ammonium persulfate (2 wt%), an oxidation inhibitor (formation of a surface protective film): quinolinic acid (0.6 wt%), and a fluoropyridine salt (0.5 wt%). ), Abrasive particles: alumina (3 wt%)
Is added to a solvent such as pure water. The pH of the slurry is
Controlled at 5. Alumina is attached to a sulfone group (charged to-) which is coordinated to pyridine because it is charged to +. It is expected that highly hydrophobic abrasive particles are formed in the slurry. Then, using this slurry, a slurry flow: 200 cc / min and a polishing pad:
IC1000 / SUBA400, DF: 300 g / cm
² , TR rotation speed: 100 rpm, TT rotation speed: 100 r
The CMP process was performed for 150 seconds under the condition of pm (FIG. 5).
(B)). When the slurry of this embodiment is supplied onto a polishing pad (turntable) during polishing, the polishing pad is hydrophobic, so that it is well compatible with hydrophobic particles. As a result, in the present invention, the polishing rate of Al was 500 nm /
min is obtained.

On the other hand, when pyridinesulfonic acid is used without a fluoromethyl group as in the prior art, the polishing rate is as low as 220 nm / min. In the present invention, the polishing rate is 2
The process time is shortened by more than twice as much. Also,
Since the abrasive particles work efficiently, it is possible to reduce the concentration of the abrasive particles, and as a result, it is expected that scratches and residual particles generated on the polished surface are reduced. In addition, there is an advantage that the slurry cost is reduced. Further, it was confirmed that pyridine adsorbed on the Al surface had an effect of preventing corrosion of Al and further had an effect of suppressing erosion. In this embodiment, an anion is used for the hydrophilic portion of the fluorine-based organic compound. However, the same effect can be obtained by using a fluorine-based surfactant having a hydrophilic portion having a potential opposite to that of the abrasive particles.

The above-described embodiments are merely examples, and the present invention is not limited to these embodiments. For example, the fluorosurfactant may be anionic, cationic, non-ionic (nonionic). These may be used as a mixture. Regarding the fluorinating agent and the fluoropyridine salt,
These may be used as a mixture, or may be used in combination with a fluorine-based surfactant or a surfactant such as an alkyl chain. The load (DF) at the time of polishing, the number of rotations of the top ring (TR) and the turntable (TT), and the like can also be appropriately changed. In addition, various modifications can be made without departing from the spirit of the present invention.

Next, referring to FIG.
The MP processing will be described. Using the slurry of the present invention, C
A CMP apparatus that performs an MP process is provided with a rotatable polishing board (turntable (TT)) 1.
A polishing pad 2 for polishing a wafer made of silicon or the like is attached on the polishing board 1. The wafer is a polishing pad 2
And is fixed to a suction cloth and a template attached to a suction plate (top ring (TR)) 3 by vacuum or water filling. Top ring (T
R) 3 is connected to the drive shaft 4
Is rotated by a motor. A slurry is supplied between the wafer fixed to the top ring 3 and the polishing pad 2. Thus, the CMP of the wafer is performed. FIG.
FIG. 2 is a perspective view of a CMP apparatus that actually performs a CMP process on a wafer using the slurry. For example, a wafer fixed to a top ring 3 attached to a drive shaft 4 rotating at a speed of about 30 revolutions / minute is mounted on a polishing pad 2 attached to a polishing board 1 rotating at a speed of about 30 revolutions / minute. Pressing is performed with a load (DF), and CMP polishing is performed while slurry supplied from a slurry supply pipe 38 derived from a slurry tank is dropped onto a processing point.

[0030]

As described above, according to the present invention, since CMP is performed using a slurry containing a fluorine organic compound, a high polishing rate can be achieved, and a stable dispersion of abrasive particles can be achieved while maintaining a polishing rate balance. A high-performance metal damascene wiring with improved CMP characteristics and less erosion can be formed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a semiconductor device manufacturing process illustrating a CMP method using a slurry according to a first embodiment.

FIG. 2 is a characteristic diagram showing a relationship between a surfactant concentration in a slurry, a dispersibility of abrasive particles, and a polishing rate balance.

FIG. 3 is a characteristic diagram showing a relationship between a Cu shaving amount and a polishing time in a CMP process.

FIG. 4 is a cross-sectional view of a semiconductor device manufacturing process illustrating a CMP method using a slurry of the first embodiment.

FIG. 5 is a cross-sectional view of a semiconductor device manufacturing process illustrating a CMP method using a slurry of the first embodiment.

FIG. 6 is a partial perspective view of a CMP apparatus illustrating a CMP method of the present invention.

[Explanation of symbols]

1 ... polishing machine (turntable TT), 2 ...
Polishing pad, 3 ... top ring, 4 ... drive shaft, 38 ... slurry supply pipe, 100, 20
0, 300: semiconductor substrate, 101, 201, 301
... insulating film, 102, 202 ... TaN liner,
103, 203 ... Cu film, 104, 204, 30
4 ... wiring groove, 105 ... contact hole, 30
2 ... Nb liner, 303 ... Al film.

Claims (10)

[Claims] 1. A slurry for chemical mechanical polishing comprising a solvent, abrasive particles dispersed in the solvent, and at least one fluorine organic compound. 2. The method according to claim 1, wherein the fluorine organic compound is
The slurry for chemical mechanical polishing according to claim 1, wherein the slurry has a fluoromethyl group and a perfluoroalkyl group in the molecule. 3. The slurry for chemical mechanical polishing according to claim 1, wherein the fluorine organic compound contains fluorine used for electrophilic fluorination. 4. The fluorine organic compound is a perfluoroalkylbedine, a perfluoroalkylethylene oxide adduct, a perfluoroalkyl oligomer, a perfluoroalkyl carboxylate, a perfluoroalkyl quaternary ammonium salt, a fluorobenzene-based intermediate, a benzenetrifluoride-based compound. Intermediate, aliphatic intermediate, N-fluoropyridinium salt, N-fluoropyrrolidone, N-fluoro-N-alkyl-arene sulfonamide, FCl
4. The method according to claim 1, wherein at least one of O ₃ , CF ₃ COOF and CH ₃ COOF is selected.
The slurry for chemical mechanical polishing according to any one of the above. 5. The slurry for chemical mechanical polishing according to claim 1, wherein the fluorine organic compound contains any one of an alkyl group, an aromatic ring, and a heteroaromatic ring. . 6. The organic compound according to claim 1, wherein the fluorine organic compound has at least one of an anion, a cation, a nonionic, and an amphoteric of an anion and a cation as a functional group. The slurry for chemical mechanical polishing according to any one of the above. 7. The concentration of the fluorine organic compound is 0.001.
2. The composition according to claim 1, wherein the content is in the range of 0.5 wt% to 0.5 wt%.
The slurry for chemical mechanical polishing according to claim 6. 8. The method according to claim 1, wherein the oxidizing agent further comprises at least one selected from ammonium persulfate, potassium persulfate, aqueous hydrogen peroxide, ferric nitrate, and ceric ammonium cerium. A slurry for chemical mechanical polishing according to claim 7. 9. The method according to claim 1, wherein the additive contains at least one of quinaldic acid, quinolinic acid, nicotinic acid, picolinic acid, malonic acid, oxalic acid, succinic acid, glycine, alanine and tryptophan. Claim 8
The slurry for chemical mechanical polishing according to any one of the above. 10. A step of forming a wiring groove on a surface of an insulating film formed on a semiconductor substrate; a step of depositing a metal film on the insulating film including the inside of the wiring groove; A step of performing chemical mechanical polishing using the slurry according to any one of claims 1 to 10 to remove a metal film other than the metal film embedded in the wiring groove. Semiconductor device manufacturing method.