JPH10275788A - Manufacture of semiconductor device and equipment for manufacturing semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and equipment for manufacturing a semiconductor device for downsizing the equipment by integrating the polishing process with the particle removal processes without damaging a surface to be polished in polishing and causing the center part to be recessed and without reducing the reliability in a semiconductor and a manufacturing yield due to the retention of polishing particles since adhered particles can be easily remored after polishing is completed. SOLUTION: When an Al alloy film, an Si film, an Si oxide film, and a nitride film are polished (CMP), a particle consisting of an organic macromolecular compound or a particle with carbon as a main constituent is used as a polishing particle. A resin that can polish a surface to be polished and can be ashed and decomposed by active rays containing ultraviolet rays may preferably be used but a methacrylic resin and polystyrene resin have spherical particles and have improved dispersion property and can be stored for a long term so that they are especially effective. After polishing using the above resin particle, active rays containing a main wavelength of 254 nm from a low-pressure mercury lamp are applied to a film to be polished and an optimum time is determined from light source output and a distance to a substrate. The rays are preferably applied in air at 50-200 deg.C. The removal of particles by decomposition under the presence of ozone proceeds.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a method for manufacturing a semiconductor device such as an VLSI and a device for manufacturing a semiconductor device. More specifically, the present invention makes it possible to extremely easily remove particles adhering after completion of polishing without damaging the surface of the surface to be processed during polishing or causing dishing. It does not cause a defect in semiconductor manufacturing such as a decrease in semiconductor reliability due to the remaining abrasive particles or a decrease in product yield, and furthermore, the polishing step and the particle removing step are easy to integrate, and The present invention relates to a method for manufacturing a semiconductor device and an apparatus for manufacturing a semiconductor device, which have an excellent feature that the size of the device can be suppressed from increasing the size of a clean room itself for separation from the next process.

[0002]

2. Description of the Related Art In recent years, various microfabrication techniques have been researched and developed for high integration and high performance of LSI. Among them, a chemical mechanical polishing method (Chemical Mechanical Polishing, hereinafter abbreviated as CMP) has attracted attention. CM
P is a technique in which the chemical action between the abrasive and the object to be polished is combined with the mechanical action of the abrasive particles during polishing. In particular, flattening of an interlayer insulating film and formation of metal plugs in a multilayer wiring forming step are performed. This is an indispensable technique in forming a buried metal wiring.

It is clear that a large amount of fine particles are generated in the CMP process because the surface of the film to be processed is flattened using an abrasive slurry and a polishing pad. Therefore, the CMP process must be performed not only in a clean room separated from other manufacturing processes but also in a cleaning process so that the generated fine particles are not carried into the next process. Since the CMP process is basically a single-wafer process in which the polishing process is performed one by one, the process includes a step of cleaning the polished work film during the polishing process of one work film. A polishing-cleaning integrated type apparatus for reducing the size and processing time is becoming mainstream.

On the other hand, from the viewpoint of increasing the speed of LSI, metals used for future metal wiring include Al and C having low resistance.
u is expected to be the mainstream, and studies are actively being conducted on using CMP for forming metal plugs and buried wirings using these metals. Generally, CM of Al or Cu
In P, an abrasive slurry composed of a mixture of inorganic particles such as alumina and an oxidizing agent such as iron nitrate and hydrogen peroxide is mainly studied.

However, since metals such as Al and Cu have low hardness, polishing with inorganic particles having high hardness such as alumina or silica may damage the surface of the metal film and cause the surface to become rough. Is embedded.

[0006] In a region where the width of the wiring metal film embedded in the groove or the opening is large, dishing in which the thickness of the central portion is small occurs. When dishing occurs, abrasive particles tend to remain at that portion. Especially Al
This tendency is remarkable in metals having low hardness such as copper and Cu. Occurrence of scratches or dishing on the surface of the metal film for wiring or residual abrasive particles increases wiring resistance,
This causes disconnection, leading to a decrease in reliability and a decrease in product yield.

[0007] In addition, the inorganic slurry easily aggregates and precipitates, and particularly when alumina having a large specific gravity is used as abrasive particles, it settles at the bottom of the container during storage. When the agglomerated slurry is used for polishing as it is, particles having a large particle size due to agglomeration damage the surface of the metal film, and the concentration of the slurry becomes non-uniform, which causes a problem in polishing stability.

Further, the metal film polished in this manner is generally brushed and washed with a nylon or polyvinyl alcohol brush while spraying ultrapure water in order to remove a slurry attached during the polishing process. In addition, if the surface of the inorganic particles is dried before washing, there is a problem that it cannot be easily removed by the subsequent washing. For this reason, there is a problem that the film to be processed after the polishing process must be stored in ultrapure water until the cleaning process is completed.

As a method of improving such a problem,
In recent years, as described in JP-A-7-86216,
There has been proposed a method of using particles mainly composed of an organic polymer compound as abrasive particles. In this method, the PMM
A polishing particle such as an organic polymer compound such as methacryl resin, phenol resin, melamine resin, polystyrene resin and polycarbonate resin such as A, or carbon black is dispersed in water together with a dispersant, and then subjected to polishing. The abrasive particles described in the present method, even if remaining on the polishing film surface,
It is described that it can be completely removed by burning with oxygen plasma or the like.

However, in this method, when polishing with inorganic particles having high hardness such as alumina or silica,
Although the problems of scratches on the metal film surface and embedding of abrasive particles in the metal film for wiring can be solved, oxygen plasma is generated because the abrasive particles remaining on the polishing film surface are burned by oxygen plasma or the like. For this purpose, it is necessary to evacuate the inside of the processing equipment, and it is not possible to cope with the integration with the polishing process.
In addition to the need for expensive equipment, there is a problem that the clean room itself for separating from the next process becomes huge.

[0011]

Under such circumstances, the problem to be solved by the present invention is to prevent the surface of the work surface from being scratched or to cause dishing during polishing, and Since the attached particles can be removed very easily, there is no occurrence of defects in semiconductor manufacturing such as a decrease in semiconductor reliability due to residual abrasive particles and a decrease in product yield. It has an excellent feature that the integration of the particle removal process is easy, and the size of the apparatus for performing the process is reduced, so that the size of the clean room itself to be separated from the next process can be suppressed. It is to provide a method for manufacturing a semiconductor device and an apparatus for manufacturing a semiconductor device.

[0012]

That is, one aspect of the present invention relates to a method of manufacturing a semiconductor device including the following (A) polishing step and (B) cleaning step. (A) Polishing step: a step of polishing a film to be processed using particles composed of an organic polymer compound or particles containing at least carbon as a main component (B) Cleaning step: After polishing obtained in the polishing step A step of irradiating the film to be processed with actinic rays containing ultraviolet rays as a main wavelength ray to wash and remove abrasive particles used for polishing.

Further, another aspect of the present invention relates to an apparatus for manufacturing a semiconductor device comprising a means for performing the above-mentioned polishing step and a means for performing the cleaning step.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The polishing step (A) of the present invention is a step of polishing a film to be processed using particles composed of an organic polymer compound or particles containing at least carbon as a main component.

The film to be processed is a pure Al film, AlSiC
Examples thereof include a film made of an alloy containing Al as a main component such as a u alloy and an AlCu alloy, a silicon oxide film, a silicon nitride film, an amorphous silicon film, a polycrystalline silicon film, and a single crystal silicon film.

The particles made of an organic polymer compound or particles containing at least carbon as a main component are not particularly limited as long as the resin can polish the surface to be polished and can be decomposed by actinic rays including ultraviolet rays. Instead, methacrylic resin, phenolic resin, urea resin, melanin resin,
Polystyrene resin, polyacetal resin, polycarbonate resin and the like can be used. Above all, methacrylic resins such as PMMA and polystyrene resins obtained by emulsion polymerization are particularly effective because they have a spherical particle shape, have extremely good dispersibility as particles, and do not undergo aggregation or sedimentation even when stored for a long period of time. Those resins copolymerized with other vinyl compounds are also effective. In addition, as the particles containing at least carbon as a main component, amorphous carbon, carbon black, or the like can be used.

The polishing using the particles composed of the above-mentioned organic polymer compound or particles containing at least carbon as a main component is carried out by using CM.
The polishing can be performed by a polishing process using the polishing method used in the P step.

In the cleaning step (B) of the present invention, the polished film to be processed obtained in the polishing step is irradiated with actinic rays containing ultraviolet rays as the principal wavelength light to wash and remove the abrasive particles used in the polishing. This is the step of performing

The actinic ray as used herein is a ray having energy to break a chemical bond between a particle composed of an organic polymer compound or at least a particle mainly composed of carbon, and has an action of ashing and decomposing particles. It is. Specifically, ultraviolet rays are used as the main wavelength light, and generally, active rays having a main wavelength of 300 nm or less are used. These actinic rays can be obtained from any light source such as a low-pressure mercury lamp and an excimer laser. For example, when a low-pressure mercury lamp is used, an actinic ray having a main wavelength of 254 nm can be obtained.

The irradiation amount of the actinic ray is proportional to the product of the intensity and the irradiation time, and the optimum time is determined by the output of the light source used and the distance from the light source to the substrate. The effect is also accelerated by heating the substrate, so that the optimum time changes.

The treatment temperature is preferably from room temperature to 300 ° C. or less, particularly preferably from 50 ° C. to 200 ° C. For example, 150
When irradiation is performed at a distance of 5 cm from the substrate using a low-pressure mercury lamp of W, the irradiation is preferably performed for 1 minute to 10 minutes when heated to 200 ° C, and for 2 minutes to 15 minutes at 100 ° C.

The atmosphere upon irradiation with actinic rays is preferably in a gas containing oxygen, and irradiation can be performed in air. Irradiation can also be performed in the presence of ozone to enhance the treatment effect. Ozone is generated by high-pressure discharge to oxygen gas in an ozone generator. About 0.1 to 3% by volume of ozone is sufficient.

As described above, the film to be polished is polished with an abrasive containing particles of an organic polymer compound or particles containing at least carbon as a main component by irradiation with actinic rays or actinic rays in the presence of ozone, and then adheres. Particles can be easily removed.

The (A) polishing step and (B) cleaning step according to the present invention may be performed independently, but a semiconductor device having both means for performing the polishing step and means for performing the cleaning step. By using the manufacturing apparatus of (1), it can be optimally implemented. In addition, before or after the step of removing adhered particles by actinic rays, debris of polishing cloth (hereinafter abbreviated as “pad”) generated during polishing processing, inorganic contaminants mixed in from the environment, and trace amounts contained in polishing particles. In order to remove metallic impurities, brush cleaning for CMP or immersion cleaning may be performed.

[0025]

EXAMPLES The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
The resin emulsion described in the following examples indicates a solution in which resin particles obtained by emulsion polymerization are dispersed.

Example 1 <Preparation of resin emulsion> 30 g of ammonium lauryl sulfate as an emulsifier, 500 g of pure water, 500 g of styrene and 500 g of methyl methacrylate as a vinyl compound were stirred and mixed to prepare a monomer emulsion of these vinyl compounds. Next, 0.9 g of ammonium lauryl sulfate and 1750 g of pure water were placed in a 5-liter stainless steel reactor having a temperature controller and a stirrer, and the temperature was raised to 75 ° C., and the inside of the reactor was replaced with nitrogen gas. Thereafter, 100 g of a 4% by weight aqueous solution of ammonium persulfate was supplied as a polymerization initiator to the reactor, and then the previously prepared monomer emulsion was supplied at a constant rate over 4 hours to obtain a copolymer of styrene and methyl methacrylate. A resin emulsion in which particles were dispersed was obtained. Styrene in the obtained emulsion
The particle concentration of the methyl methacrylate copolymer was 30.2% by weight. Microscopic observation revealed that the resin particles were spherical with an average particle size of 0.1 micron, and no aggregate of the resin particles was observed. This resin emulsion is 6
No sedimentation of the resin particles or aggregation of the particles was observed even after standing for a month.

<Polishing Step and Washing Step> Aqueous ammonia and pure water were added to the methacrylic resin emulsion obtained above to prepare an alkaline slurry having a pH of 11 and a resin particle concentration of 10% by weight. Using this abrasive slurry, a wafer having an Al film formed by sputtering was polished. The polishing conditions were such that the number of rotations of the rotary platen was 50.
0 rpm, the number of rotations of the wafer holder 75 rpm, the polishing pressure 250 g / cm ² , the polishing slurry flow rate 55 ml / min,
Polishing time was 1 minute. The polishing rate of Al was 610 Å / min.

As a result of spin-drying the polished wafer,
Particles remained on the surface, and as a result of microscopic IR analysis, a peak derived from the methacrylic resin was confirmed. The dried wafer was placed between a quartz plate heated to 200 ° C. and a 150 W low-pressure mercury lamp, and particles were removed for 5 minutes while supplying ozone generated by an ozone generator to the wafer surface. The ozone concentration at this time was 2%.

No particles remain on the surface after the treatment,
As a result of the microscopic IR analysis, the peak derived from the methacrylic resin had disappeared. After that, impurities introduced into the wafer other than the resin particles were removed by washing in a CMP brush washing machine, and after the drying treatment, the number of particles on the wafer surface was measured. As a result, the surface was cleaned to the particle level before the polishing treatment step.

[0030]

As described above, according to the present invention, it is possible to extremely easily remove particles adhering after completion of polishing without damaging the surface of the work surface or causing dishing during polishing. It is possible to reduce the reliability of the semiconductor due to the remaining abrasive particles, and to prevent defects in semiconductor manufacturing such as a decrease in product yield, and to easily integrate the polishing step and the particle removing step. In addition, a semiconductor device manufacturing method and an apparatus for manufacturing a semiconductor device having an excellent feature that the size of an apparatus for carrying out the process can be reduced, so that the size of the clean room itself to be separated from the next process can be suppressed. Could be provided.

Claims (5)

[Claims] 1. A method for manufacturing a semiconductor device comprising the following (A) polishing step and (B) cleaning step. (A) Polishing step: a step of polishing a film to be processed using particles composed of an organic polymer compound or particles containing at least carbon as a main component (B) Cleaning step: After polishing obtained in the polishing step A step of irradiating the film to be processed with actinic rays containing ultraviolet rays as a main wavelength ray to wash and remove abrasive particles used for polishing. 2. The method according to claim 1, wherein the abrasive particles are a methacrylic resin, a polystyrene resin obtained by an emulsion polymerization method, or a resin obtained by copolymerizing these with other vinyl compounds. 3. The method according to claim 1, wherein the actinic ray is irradiated in the presence of ozone. 4. The method according to claim 1, wherein the actinic ray is a ray containing a main wavelength of 300 nm or less. 5. An apparatus for manufacturing a semiconductor device, comprising: means for performing a polishing step according to claim 1; and means for performing a cleaning step.