JP2000311868A - Method and system for treating surface using negative ions and fabrication of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress charge-up damage while simplifying the arrangement by generating hydrogen radicals using a gas containing hydrogen or hydrogen elements, generating hydrogen ions by attaching electrons to hydrogen radicals and projecting hydrogen ions to a basic body thereby treating the basic body. SOLUTION: A gas containing hydrogen or hydrogen elements is introduced from a process gas inlet and the pressure thereof is set at a specified level. Subsequently, power is supplied from a microwave power supply 101 to generate a microwave discharge plasma 113. Electrons are fed to hydrogen radials introduced into a negative ion generation chamber 105 using an electron supply unit 104 connected therewith. A DC voltage is applied to a first grid electrode disposed in a vacuum container. A magnetic filter 107 must be provided between the negative ion generation chamber 105 and a basic body treating chamber. A basic body supporting base 111 is disposed in the downstream direction of negative ions. Furthermore, a grid electrode for capturing secondary electrons is disposed immediately in front of the supporting base 111.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface treatment apparatus, a surface treatment method, and a method for manufacturing a semiconductor device, and more particularly, to connecting a wiring layer or a wiring layer to a diffusion layer in a wiring forming step in a semiconductor manufacturing process. In a method of manufacturing a semiconductor device in which a metal is buried in a fine contact hole for forming a metal film on a barrier metal in a contact hole by a chemical vapor deposition method before forming a metal film on the barrier metal in the contact hole. The present invention relates to an apparatus and a method used for the method.

[0002]

2. Description of the Related Art Along with miniaturization of a semiconductor device, between a diffusion layer formed on a surface of a semiconductor substrate and a metal wiring layer,
Contact holes for connecting different metal wiring layers have become finer, and their aspect ratio (depth / opening dimension) has far exceeded 1. Conventionally, a sputtering method has been used as a method of forming a wiring metal film in such a contact hole. However, it is difficult to satisfactorily embed a metal film into a minute contact hole by a sputtering method, and despite various improvements such as a bias sputtering method, a collimation sputtering method, and a long throw sputtering method, the It is said that the limit is an aspect ratio of about 2. Therefore, a chemical vapor deposition (CVD) method has been used as a method for filling fine contact holes having an aspect ratio of 2 or more. As for embedding of metal into fine contact holes by CVD, embedding of tungsten using tungsten hexafluoride gas is widely used in mass production lines at present. The embedding into a fine contact hole by the method has been studied.

Various studies have been made on aluminum and copper as films formed by low-resistance wiring metal by the CVD method. Among these, particularly for aluminum, a high quality film quality and a high film formation rate have been achieved by a thermal CVD method using DMAH (dimethyl aluminum hydride) and hydrogen, and as a material for filling contact holes next to tungsten, Attracting attention.

The aluminum wiring forming process by the CVD method is performed, for example, in the following steps. First, after forming a contact hole in an insulating film by dry etching and performing cleaning, a base metal film such as titanium nitride, which is called a barrier metal, is formed on the entire surface of the substrate including the inside of the contact hole and the surface of the insulating film. Next, for the purpose of removing surface contaminants such as titanium nitride, which is a base metal,
Cleaning using plasma is performed, and further, the substrate is transferred to a CVD chamber while being kept in a vacuum, and an aluminum film is deposited using DMAH and hydrogen.

Here, plasma cleaning before depositing aluminum is performed by physically sputtering the substrate surface using an inert gas plasma such as argon, or cleaning the substrate surface using a halogen gas plasma such as chlorine. A method of etching (JP-A-7-226387) and a method of reducing an oxide layer on the substrate surface using hydrogen plasma (JP-A-8-298288) are disclosed. In the case of an inert gas, sputtering is performed. It is difficult to completely remove oxygen from the surface because the oxygen adhering to the substrate surface, and in the case of halogen gas, it is difficult to completely remove the adsorbed halogen element. The treatment with hydrogen plasma is considered to be optimal because the aluminum to be filmed may corrode.

The removal of surface oxide films and organic substances by hydrogen plasma is described in the literature (Real-T) on a silicon substrate.
im, In Situ Monitoring of
Room-Temperature Silicon
Surface Cleaning Using H
ydrogen and Ammonia Plasm
as. Zhen-Hong Zhou et. al.
J. Electrochem. Soc. Vol. 140
No. 11 (1993) p3316) and GaAs
For the s substrate, refer to the literature (GaAs cleanin).
g with ahydrogen radical
beam gunin an ultrahigh-v
acumum system. S. Sugate et.
al. J. Vac. Sci Technol. B6
(4) It is described in p1087 (1988). In the literature, Si—O bonds on the silicon surface are reduced by the incidence of energetic hydrogen ions, oxygen is removed in the form of H ₂ O, and the silicon surface is hydrogen terminated in the form of Si—H. Further, it is described that organic substances react only with hydrogen radicals and are removed in the form of CHx. In consideration of the mechanism of removing the surface oxide film and organic substances by the reducing action, the cleaning treatment using the hydrogen plasma considers not only the silicon and GaAs surfaces but also the T
It is considered that, also in the cleaning of the surface of a barrier metal such as iN or TaN or a metal such as Al or Cu, the energy of incident ions is changed to work effectively.

In a conventional plasma cleaning process, for example, as shown in page 41 of the integrated circuit process technology series, semiconductor dry etching technology (edited by Tokuyama Wei, published by Sangyo Tosho Co., Ltd.)
It has mainly used positive ions.

FIG. 7 shows a cross section of a conventional parallel plate type plasma processing apparatus. In FIG. 7, 70
1 is a high frequency power supply, 751 is a high frequency application electrode, 710 is a semiconductor substrate, 752 is an ion sheath, 753 is plasma,
754 denotes a vacuum vessel, 755 denotes a ground electrode, and 702 denotes a process gas inlet. In this apparatus, an electrode 751 for applying a high frequency to generate plasma is provided in a vacuum vessel 754. The substrate 710 to be processed is provided on the electrode 751 to which a high frequency is applied. When a high frequency is applied to the electrodes, a plasma 753 is generated between the high frequency application electrode 751 and the installation electrode 755 which are installed in parallel. At this time, an electron-deficient region called an ion sheath 752 is generated between the plasma 753, the high-frequency application electrode 751, and the vacuum container 754 due to a difference in mobility between ions and electrons in the plasma 753. On the other hand, the plasma has a positive potential on average.
The electrode 751 to which a high frequency is applied has a larger potential difference with respect to the plasma than the electrode 755 which is grounded, and may have a maximum of several hundred volts. Positive ions in the plasma 753 are accelerated to such a potential of the sheath and enter the substrate to be processed 710 with a certain energy. Using the energetic particles, etching and cleaning are performed on the substrate surface. Until now, in the semiconductor manufacturing process, only positive ions have been used as described above, and negative ions have hardly been used. But recently,
Attention has been paid to negative ions in process plasma containing halogen atoms, and several plasma processing methods using negative ions have been proposed.

[0009]

However, in the conventional treatment using positive ions, positive charges are accumulated on the surface of the substrate to be treated during the treatment. This is due to the lateral velocity difference due to the thermal motion of ions and electrons. Light electrons have a large lateral velocity and do not reach the bottom of a deep hole, but ions have a large mass and a lateral velocity. Is a phenomenon that positive charges are accumulated at the bottom of the deep hole in order to reach the bottom of the deep hole. This charging phenomenon is further amplified by the emission of secondary electrons due to ion energy impact. Due to this charging, a large electric field higher than the withstand voltage is applied to the gate oxide film of the field effect transistor to cause dielectric breakdown, and the charge of the resist mask bends the trajectory of positive ions incident on the substrate to be processed by Coulomb force, thereby etching. Problems such as a collapse of the shape have occurred.

[0010] In order to improve such abnormalities, there has been proposed a plasma treatment without charge by alternately irradiating positive ions and negative ions as disclosed in, for example, JP-A-8-181125. However, in this method, the charge of the incident ions has the same number of positive and negative signs, so it seems that the charge neutrality is maintained. However, as described in the previous section, the emission of secondary electrons due to the ion energy impact occurs. ing. Secondary electron emission from the substrate surface is generated when the energy of incident ions is about 10 eV or more. Therefore, in a process using energetic particles, charging of the surface of the substrate to be processed due to secondary electron emission cannot be avoided. In view of the above facts, even in the above technique, the surface of the substrate to be treated is still positively charged, though the degree is lighter than the treatment using only positive ions.

Further, Mizutani, T. et al. an
d Nishimatsu, S, "Sputterin
g Yield and Radiation Dam
age by Neutral Beam Bomba
rdment, "J. Vac. Sci & Techn.
ol. , Vol. A6, p1417, (1988), a plasma treatment without neutralization by neutral particles has also been proposed. However, in this method as well, the incident particles have no charge, but secondary electrons are emitted by the energy impact of the particles in the same manner, so that the surface of the substrate to be processed is still positively charged.

In order to solve the above problems, there has been proposed a process which preferentially uses negative ions. In a conventional processing apparatus using negative ions, plasma is generated in the same room as a processing space in which a substrate is installed, and negative ions are extracted from the plasma and incident on the substrate. But,
In such an apparatus structure, there is a problem that high-energy ions and high-energy photons in the plasma enter the substrate and cause damage.

A conventional negative ion generator has been mainly used for neutral beam injection heating of a nuclear fusion device. In the electron beam excited hydrogen negative ion source disclosed in Japanese Patent Application Laid-Open No. 7-14020, generation of hydrogen negative ions by an electron beam is performed by H ₂ → H ₂ ^* by high energy electrons and H ₂ ^* by low energy electrons ^. → H ^{+ +} H ^- is performed by using the two reactions that. However, since the two reactions are performed with an electron beam, there are problems such as difficulty in controlling the energy of the electron beam and a complicated device structure.

An object of the present invention is to realize a surface treatment apparatus and a surface treatment method using negative ions with a simple apparatus configuration.

It is another object of the present invention to provide a vapor phase processing apparatus with less charge-up damage and a method for satisfactorily embedding metal in fine contact holes using the apparatus.

[0016]

According to the present invention, there is provided a method of manufacturing a semiconductor device before forming an aluminum film, wherein hydrogen radicals are generated using hydrogen or a gas containing a hydrogen element. In this method, hydrogen negative ions are generated by attaching electrons to the hydrogen radicals, and the hydrogen negative ions are incident on the substrate to be processed.

Further, an apparatus for generating negative ions includes:
In a vacuum vessel comprising a substrate processing chamber (processing space) and a negative ion generation chamber (generation space), a gas is introduced into a plasma generation chamber connected to the negative ion generation chamber (generation space) via a transport pipe. Connects to a radical supply device that generates plasma and recombines short-lived ions in the transport pipe to extract only long-lived radicals and supplies them to the negative ion generation chamber (generation space), and a negative ion generation chamber (generation space) And
An electron supply device that supplies electrons to the negative ion generation chamber; a negative ion generation chamber that generates negative ions by attaching electrons supplied from the electron supply device to radicals supplied from the radical supply device; A grid to which at least one DC voltage is applied for taking out negative ions from the generation chamber and accelerating to a predetermined energy, and a conductive support to which a DC voltage is applied for placing a substrate to be processed in a vacuum vessel It has a table and a grid electrode, which is provided on the substrate to be processed and is applied with a DC voltage, for capturing secondary electrons emitted from the substrate to be processed.

The substrate to be treated by the surface treatment apparatus has a concave portion formed in an insulating film deposited on a semiconductor substrate, a barrier metal formed on an inner surface or a bottom surface of the concave portion, and the concave portion has a contact hole, It has one of a via hole, a wiring groove having a single damascene structure, and a wiring groove having a dual damascene structure.

The gas introduced into the radical generating and supplying means is a gas containing hydrogen or a hydrogen element.

The plasma generating means may be a microwave discharge type, a capacitive coupling type, an inductive coupling type, a magnetron type,
It is preferable to use one of a helicon wave type, an ECR type, a surface wave type, and a surface wave interference type using a flat multi-slot antenna.

Further, at least the inner surfaces of the plasma generating means and the transporting means are made of a material containing no oxygen.
InN, SiC, etc. are selected.

Further, the electron supply means is a triode type, hot filament type or field emission type electron gun or the like.

[0023] Further, the apparatus is characterized in that the substrate supporting means has a means for applying a positive DC voltage or a pulse-like voltage.

Further, a method of manufacturing a semiconductor device according to the present invention
An insulating film having a concave portion for forming a wiring is formed on the substrate to be processed, and a surface of the insulating film and an inner peripheral surface of the concave portion are formed.
Alternatively, in a method for manufacturing a semiconductor device in which a barrier metal is formed on the bottom surface of the concave portion, the surface of the barrier metal is cleaned, and a metal for wiring is subsequently deposited by using a chemical vapor deposition method, Is a method of performing processing by supplying negative ions to the substrate to be processed.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A plasma processing apparatus and a processing method according to the present invention will be described with reference to FIG. In FIG.
Is a microwave power supply, 102 is a process gas inlet, 10
3 is a transport pipe, 104 is an electron supply device, 105 is a negative ion generation chamber (generation space), 106 is a negative ion confinement magnet, 107 is a magnetic filter, 108 is a substrate processing chamber (processing space), and 109 is One grid, 110 is a substrate to be processed, 111 is a support for the substrate to be processed, and 112 is a DC power supply.

First, a gas containing hydrogen or a hydrogen element is introduced from the process gas inlet 102 to set the pressure to a predetermined value, and power is supplied from the microwave power supply 101 to generate a microwave discharge plasma 113. .

Of the positive ions, electrons and radicals generated in the plasma, the positive ions and electrons recombine and become neutral as they are transported through the transport tube 103, while the radicals have a relatively long lifetime. Therefore, it is unlikely to recombine even in the transport tube, and when it reaches the negative ion generation chamber (generation space) 105, most of it is hydrogen (atom, molecule) radicals and hydrogen molecules.

As described above, when radicals are generated by high-frequency discharge, the device structure is simpler, a large amount can be generated, and controllability is much improved as compared with the case of using an electron beam.

Further, electrons are supplied to the hydrogen radicals introduced into the negative ion generation chamber by using an electron supply device 104 connected to the negative ion generation chamber 105. As the electron supply device, for example, an electron gun of a triode type, a hot filament type, a field emission type, or the like can be considered, but any other device that emits electrons may be used.

According to the above-described method, hydrogen radicals and electrons are simultaneously supplied to the negative ion generation chamber, and electrons are attached to the hydrogen radicals to generate hydrogen negative ions. Further, it is considered that the addition of an element that easily dissociates electrons into the negative ion generation chamber increases the electron density and further promotes the reaction. Examples of elements that can easily dissociate electrons include alkali metals such as cesium and rubidium, and alkaline earth metals such as barium, strontium, and calcium.

Negative ions and electrons generated in the negative ion generation chamber diffuse into the chamber walls and recombine, thereby lowering their density. In order to prevent this, a magnet for forming a multipolar magnetic field may be provided on the outer wall of the negative ion generation chamber.

FIG. 2 is a top view of the cross section of the negative ion generation chamber 105 of FIG. 1 in order to clarify the arrangement of magnets required to form a multipole magnetic field. It is a permanent magnet for confinement. With the magnet arrangement as shown in the figure, diffusion of the charged particles to the wall can be suppressed, and the negative ions can be confined in the negative ion generation chamber with high density.

In order to extract negative ions from the gas containing a large amount of negative ions generated as described above, the first grid electrode 109 is provided in a vacuum vessel. Further, a DC voltage of V1 is applied to the first grid electrode so that V1> 0. By applying a voltage to the grid electrode in this manner, the negative ions become approximately V1 (e
V) and is pulled out in the grid direction. By adjusting the value of V1, the energy of the negative ions can be arbitrarily adjusted. FIG. 1 shows an example in which one grid electrode is provided for extracting negative ions. However, two or more grid electrodes may be provided.

In the present negative ion generating method, since a large amount of electrons are emitted from the electron gun, a large amount of electrons other than negative ions are present in the negative ion generating chamber. In order to remove electrons from a gas containing both negative ions and electrons, it is necessary to install a magnetic filter 107 between the negative ion generation chamber and the substrate processing chamber (processing space).

FIG. 3 shows the specific structure and principle of the magnetic filter, and 320 is a permanent magnet. The magnetic filter is formed by arranging two permanent magnets having the magnetic pole arrangement shown in FIG. 3 in parallel, and a magnetic field is formed in a direction perpendicular to an electric field in the device. When the particles that move during electrolysis come to the region where the magnetic field is applied, Lorentz force acts and receives a force perpendicular to the electric and magnetic field directions. The electron 321 and the negative ion 322 having the same charge receive the same magnitude of force, but the electron 321 having a small mass is largely bent, whereas the trajectory of the heavy ion 322 is hardly changed. For this reason, most electrons collide with the vacuum vessel wall, and only negative ions enter the substrate.

The substrate support 111 to be processed is placed downstream of the negative ions extracted as described above. Also,
A grid electrode for capturing secondary electrons is provided immediately before the support. In FIG. 1, the first grid electrode 109 is
Also serves as a secondary electron capture grid. DC voltages Vs and V1 are applied to the support and the first grid, respectively, and V1>
The voltage value is set so that Vs> 0. As described above, the negative ions extracted from the plasma are approximately Vs
The light having an energy of (eV) is incident on the substrate 110 to be processed. The secondary electrons emitted from the surface of the substrate 110 are accelerated by the electric field of V1−Vs and are captured by the first grid, and excessive negative charges are accumulated on the surface of the substrate 110. To prevent. By adjusting the potentials of V1 and Vs, it is possible to arbitrarily adjust the incident energy of negative ions on the substrate 110 and the amount of secondary electrons emitted from the substrate surface. When the substrate 110 to be processed is directly installed on the support 111, the negative charges accumulated on the surface of the substrate 110 are transferred to the support 1 through the gate oxide film.
11 and may result in gate oxide breakdown. In order to prevent this, the support 111
An insulating plate may be provided between the substrate 110 and the substrate to be processed 110. As the material of the insulating plate, for example, alumina, alumina nitride, or the like can be considered. However, any material that has insulating properties and high plasma resistance can be used.

When processing is performed using the apparatus having the above structure, neutral radicals other than negative ions enter the substrate to be processed because neutral radicals are not intentionally eliminated. However, since the kinetic energy of the incident radical is very low, the radical only adheres to the surface of the substrate to be treated, and a cleaning effect by a spontaneous reaction can hardly be expected. However, when negative ions having energy are incident on the surface where hydrogen is adsorbed, a so-called ion assist reaction occurs, and the reaction speed is considered to be faster than when only negative ions are incident. That is, although the presence of neutral radicals has the merit of increasing the cleaning speed, it can be said that there is no demerit, so there is no need to intentionally eliminate it.

When the treatment is performed using negative ions, the following effects are exerted on the substrate to be treated. First, even if negative ions are incident on the substrate, the incident energy is 10 eV.
Above this level, secondary electrons are emitted, so that negative charging can be prevented. Further, even when the incident energy becomes several tens eV or more and the number of emitted secondary electrons becomes two or more, the effect that the electrons are pulled back to the positively charged substrate to be processed is exerted. I do. JP-A-7-122439
In Japanese Patent Application Laid-Open Publication No. H10-209, processing with low energy ions of 20 eV or less is proposed, but the above-described charge suppression effect is not lost even with energy of 20 eV or more. Another advantage of the negative ions is that the temperature of the surface of the substrate to which the negative ions are incident is lower than that of the positive ions. This is because the reaction of returning positive ions to neutral atoms is an exothermic reaction, whereas the reaction of returning negative ions to neutral atoms is an endothermic reaction. As a result, even if negative ions are incident on the substrate to be processed, the local substrate surface temperature near the ion incident point is lower than when positive ions are incident,
Thermal damage to the substrate (for example, crystal disorder or deterioration of the photoresist mask) is reduced. As described above, by using negative ions, there is no charge on the surface of the substrate to be processed, there is no electrostatic breakdown of the gate oxide film, and a good cleaning process with little thermal damage to the substrate to be processed is realized. Is done.

As a first embodiment of the present invention, an example in which a multilayer wiring in a semiconductor manufacturing process is applied to a cleaning process before forming an upper metal wiring in a via hole forming process for connecting different wiring layers.

The sectional structure of the semiconductor substrate processed in this embodiment will be described with reference to FIG. In FIG. 4, 43
1 is a silicon substrate, 432 is an element isolation oxide film, 433 is a gate oxide film, 434 is a gate electrode, 435 is a first interlayer oxide film, 436 is a first layer metal wiring, and 437 is a barrier metal of a first layer metal wiring. 438, an antireflection film for the first-layer metal wiring, 439, a second interlayer oxide film, 440, a via hole formed by dry etching, 441, a thin oxide layer on the surface of the antireflection film, and 442, dry etching for forming a via hole. It is a residue of the polymer adhered therein.

In the via hole on the silicon substrate surface, a natural oxide film, crystal defects introduced by ion bombardment at the time of etching, or polymer residue 442 attached during dry etching remain. When a two-layer metal wiring is formed, the resistance value of the via hole increases due to a natural oxide film, crystal defects and impurities, resulting in circuit delay and poor wiring continuity. Therefore, these residues need to be removed by cleaning. However, if the substrate is taken out into the air after the cleaning process, a natural oxide film grows again on the cleaned surface. Therefore, it is desirable that the substrate be kept in a vacuum from the cleaning to the formation of the second-layer metal wiring. As a method for manufacturing a semiconductor device that satisfies this requirement, a method using plasma is widely and generally used, but the problem here is the charge-up phenomenon due to plasma. When this cleaning is performed by the conventional positive ion treatment, the positive charges introduced from the plasma flow to the gate electrode 434 through the first-layer metal wiring 436, and finally, the gap between the silicon substrate 431 and the gate electrode 434. A voltage is applied to the gate oxide film 433 existing in the region. When this voltage reaches the breakdown voltage, the gate oxide film 433 is damaged by electrostatic discharge. Even when the breakdown voltage is lower than the breakdown voltage, a minute tunnel current flows through the gate oxide film 433, so that the life of the gate oxide film 433 is significantly deteriorated.

The semiconductor substrate having the above structure is placed on the base support 111 of the apparatus shown in FIG. afterwards,
The negative ion generation chamber 105 and the semiconductor substrate processing chamber (processing space) 108 are evacuated through an exhaust system, and the degree of vacuum is 5 × 1.
The pressure is reduced until the pressure becomes 0 ^-6 Torr. Thereafter, 150 sccm of hydrogen gas is supplied from the process gas inlet 102,
The pressure in the semiconductor substrate processing chamber 108 was set to 10 mTorr by adjusting a slot valve (not shown) provided in the exhaust system. Here, a power of 250 W is supplied from the microwave power supply 101 to the waveguide 114 to generate a microwave discharge plasma 113. The generated plasma is recombined in the transport tube, and is transported about 50 cm downstream, and most of the plasma is supplied to the negative ion generation chamber 105 as hydrogen radicals.

Next, the hot filament type electron supply device 10
A current of 50 A is passed through the filament No. 4 and a voltage of 5 V is applied to an extraction electrode (not shown) in the electron supply device. Thereby, the thermoelectrons emitted from the filament are supplied into the negative ion generation chamber with energy of about 5 eV. In the negative ion generation chamber, the hydrogen radicals and electrons adhere to generate negative hydrogen ions.

To extract the negative hydrogen ions, a DC voltage of 55 V is applied to the first grid 109. Furthermore,
A DC voltage of 50 V is applied to the semiconductor substrate support 111. When the above voltage is applied to each grid, negative ions are incident on the semiconductor substrate 110 at an energy of about 50 eV. Excess secondary electrons emitted from the substrate are attracted to the electric field of 5 V, and the first grid 10
9 is captured.

The treatment with hydrogen negative ions described above
After the operation is performed for 0 second, the substrate is moved to the metal wiring film forming chamber while the vacuum is maintained, and the second layer metal wiring is deposited. The surface morphology of the deposited film is good and its reflectivity shows a value of 200% with respect to the silicon substrate. Subsequently, through a process such as patterning with a photoresist and dry etching, a second-layer metal wiring was formed, and the characteristics of the semiconductor element were evaluated.

FIG. 5 shows the results of an investigation on the charge (Qbd) that causes the gate oxide film to break down in a semiconductor device that has been subjected to via-hole cleaning by a conventional method and a method using negative hydrogen ions. In this embodiment, the gate oxide film pressure 10
The measurement was performed using 100 nm-type NMOS capacitive elements. In FIG. 5, the horizontal axis represents the Qbd value, and the vertical axis represents a certain Q value.
The number of broken elements is represented by the bd value. As shown in the figure, when the present invention was used, there was no device in which the performance of the gate oxide film deteriorated.

As described above, when the treatment using only negative ions according to the present invention is performed, the potential of the first-layer metal wiring can be suppressed to several volts or less, which is the operating voltage of the semiconductor element, so that the electrostatic breakdown naturally occurs. And its life is hardly degraded.

As a second embodiment of the present invention, in a via hole forming process for connecting different wiring layers of a multilayer wiring in a semiconductor manufacturing process, a cleaning process shown in FIG. An example is shown in which the device of FIG. The only difference between the apparatus shown in FIG. 6 and the apparatus shown in FIG. 1 is that the plasma generation method is of the microwave discharge type in FIG. 1, whereas it is of the ICP discharge type in FIG. 613 is ICP discharge plasma, 614 is IC
5 shows a P discharge antenna.

A semiconductor substrate having the structure shown in FIG.
It is set on the base support 611 of the apparatus shown in FIG. Thereafter, the negative ion generation chamber 605 and the semiconductor substrate processing chamber 608 are evacuated through an exhaust system, and the degree of vacuum is set to 5 × 10 ⁻⁶ T.
Reduce the pressure until it reaches orr. Thereafter, 150 sccm of hydrogen gas is supplied from the process gas inlet 602, and the pressure of the semiconductor substrate processing chamber 608 is set to 10 mTorr by adjusting a slot valve (not shown) provided in the exhaust system. Here, 200 W of power is supplied from the high frequency power supply 601 to the antenna 614 to generate ICP discharge plasma 613. The generated plasma is recombined in the transport pipe 603, and when transported about 50 cm downstream, most of it becomes hydrogen radicals and is supplied to the negative ion generation chamber.

Next, the hot filament type electron supply device 60
A current of 50 A is passed through the filament No. 4 and a voltage of 5 V is applied to an extraction electrode (not shown) in the electron supply device. Thereby, the thermoelectrons emitted from the filament are supplied into the negative ion generation chamber with energy of about 5 eV. In the negative ion generation chamber, the hydrogen radicals and electrons adhere to generate negative hydrogen ions.

To extract the hydrogen negative ions, a DC voltage of 55 V is applied to the first grid 609. Furthermore,
A DC voltage of 50 V is applied to the semiconductor substrate support 611. When the voltage is applied to each grid, negative ions are incident on the semiconductor substrate 610 at an energy of about 50 eV. Excess secondary electrons emitted from the substrate are attracted to the electric field of 5 V, and
9 is captured.

The treatment with hydrogen negative ions described above
After the operation is performed for 0 second, the substrate is moved to the metal wiring film forming chamber while the vacuum is maintained, and the second layer metal wiring is deposited. The surface morphology of the deposited film is good and its reflectivity shows a value of 210% with respect to the silicon substrate. Subsequently, a second layer metal wiring is formed through processes such as patterning with a photoresist and dry etching.

As described above, when the treatment using only negative ions according to the present invention is performed, the potential of the first-layer metal wiring can be suppressed to several volts or less, which is the operating voltage of the semiconductor element. And its life is hardly degraded.

[0054]

As described above, by using hydrogen negative ions, there is no electrostatic breakdown of the gate oxide film due to the charging of the surface of the substrate to be processed, and good film quality can be obtained in the subsequent metal film formation. The resulting cleaning is realized.

Further, according to the present invention, the charge-up damage can be significantly reduced by using negative hydrogen ions when cleaning before embedding a metal in the contact hole.

According to the present invention, the hydrogen negative ion is
The hydrogen radicals generated by the high-frequency discharge are guided to a negative ion generation chamber downstream, and the hydrogen radicals are irradiated with an electron beam to generate hydrogen negative ions by an electron attachment reaction, whereby plasma is generated in the negative ion generation chamber. Since they do not exist, there is no possibility that high-energy ions or high-energy photons existing in the plasma are incident on the substrate, and a low-damage cleaning process can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing an embodiment of a negative ion processing apparatus using a method for generating hydrogen negative ions by supplying electrons to hydrogen radicals, which is one embodiment of the present invention.

FIG. 2 is a drawing of a cross section of the negative ion generation chamber of FIG. 1 viewed from above in order to clarify the arrangement of the negative ion confining magnet in FIG.

FIG. 3 is a diagram for explaining the structure and principle of a magnetic filter described in FIG. 1;

FIG. 4 is a cross-sectional view of the semiconductor device for explaining the removal of a thin oxide film on the surface of the antireflection film at the bottom of the via hole according to the first embodiment of the present invention.

FIG. 5 is a diagram showing a difference in deterioration of a semiconductor device processed using the conventional technique and the present invention in the first embodiment of the present invention.

FIG. 6 shows a method of generating plasma in a negative ion processing apparatus using a method of generating hydrogen negative ions by supplying electrons to hydrogen radicals according to the second embodiment of the present invention.
It is the figure which showed typically the form of the apparatus at the time of performing by CP type discharge.

FIG. 7 is a conceptual diagram of a configuration of an apparatus conventionally used for a plasma etching process.

[Explanation of symbols]

 Reference Signs List 101 Microwave power supply 102 Process gas inlet 103 Transport pipe 104 Electron supply device 105 Negative ion generation chamber (generation space) 106 Negative ion confinement magnet 107 Magnetic filter 108 Substrate processing chamber (processing space) 109 First grid 110 Processing substrate 111 Substrate support 112 DC power supply 113 Microwave discharge plasma 114 Waveguide 320 Permanent magnet 431 Silicon substrate 432 Element isolation insulating film 433 Gate oxide film 434 Gate electrode 435 First interlayer oxide film 436 First layer metal wiring 437 Barrier metal of first layer metal wiring 438 Antireflection film of first layer metal wiring 439 Second interlayer oxide film 440 Via hole 441 formed by dry etching 441 Thin oxide layer on antireflection film surface 442 Residue of polymer 601 High frequency power supply 602 Pro Gas inlet 603 Transport pipe 604 Electron supply device 605 Negative ion generation chamber (generation space) 606 Plasma confinement magnet 607 Magnetic filter 608 Substrate processing chamber (processing space) 609 First grid 610 Substrate 611 Substrate support 612 DC power supply 613 ICP discharge plasma 614 ICP discharge antenna 701 High frequency power supply 751 High frequency application electrode 710 Semiconductor substrate 752 Ion sheath 753 Plasma 754 Vacuum container 755 Ground electrode 702 Process gas inlet

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5F033 KK01 NN06 NN07 QQ02 QQ09 QQ11 QQ37 QQ92 QQ98 VV06 XX28

Claims (27)

[Claims] A vacuum chamber for providing a processing space for a substrate to be processed and a negative ion generation space communicating therewith; a radical generation supply unit communicating with the negative ion generation space; and an electron supply connected to the negative ion generation space. Negative ions, comprising: means, a substrate supporting means for setting the substrate to be processed in the substrate processing space, and means for causing the negative ions to be incident on the substrate. Surface treatment equipment using 2. The surface treatment apparatus using negative ions according to claim 1, wherein the gas introduced into said radical generation and supply means is a gas containing hydrogen or a hydrogen element. 3. The negative ion according to claim 1, wherein said radical generation and supply means comprises plasma generation means and means for transporting plasma generated by said plasma generation means downstream. Surface treatment equipment using 4. The plasma generating means is any one of a microwave discharge type, a capacitive coupling type, an inductive coupling type, a magnetron type, a helicon wave type, an ECR type, a surface wave type, and a surface wave interference type using a flat plate multi-slot antenna. The surface treatment apparatus using negative ions according to claim 3, wherein: 5. The surface treatment apparatus using negative ions according to claim 3, wherein at least the inner surfaces of the plasma generating means and the transporting means are made of a material not containing oxygen. 6. The surface treatment apparatus using negative ions according to claim 1, wherein said electron supply means is a triode type, a hot filament type or a field emission type electron gun. 7. The surface treatment apparatus using negative ions according to claim 1, further comprising means for capturing electrons between the negative ion generation space and the processing space of the substrate to be processed. 8. The surface treatment apparatus using negative ions according to claim 7, wherein the means for capturing the electrons is a magnetic filter. 9. The surface treatment apparatus using negative ions according to claim 1, wherein a magnetic field forming means is provided in the negative ion generation space. 10. The surface treatment apparatus using negative ions according to claim 9, wherein the magnetic field formed in the negative ion generation space is a multipole magnetic field. 11. The surface using negative ions according to claim 1, wherein the means for causing the negative ions to be incident on the substrate to be processed is at least one or more grid electrodes to which a DC voltage is applied. Processing equipment. 12. The surface treatment apparatus using negative ions according to claim 1, further comprising means for applying a positive DC voltage or a pulse-like voltage to said substrate-to-be-processed supporting means. 13. The negative electrode according to claim 1, wherein a means for capturing secondary electrons emitted from the substrate to which a positive voltage is applied is installed on the substrate to be processed. Surface treatment equipment using ions. 14. An insulating film having a concave portion for forming a wiring is formed on a substrate to be processed, and a barrier metal is formed on the surface of the insulating film and on the inner peripheral surface of the concave portion or on the bottom surface of the concave portion. Cleaning the surface of the barrier metal, and subsequently depositing a wiring metal using a chemical vapor deposition method, wherein the method of manufacturing a semiconductor device on the surface of the barrier metal includes the step of subjecting the negative ions to the treatment. A method for manufacturing a semiconductor device, wherein the method is a method of performing processing by supplying to a substrate. 15. The method according to claim 14, wherein the recess formed in the insulating film is a contact hole or a via hole. 16. The method according to claim 14, wherein the concave portion formed in the insulating film is a single damascene or dual damascene wiring groove. 17. The method according to claim 14, wherein the negative ions are negative ions of hydrogen. 18. The method of manufacturing a semiconductor device according to claim 14, wherein the method of generating negative ions is a method of simultaneously supplying radicals and electrons into a negative ion generation space. 19. The method according to claim 18, wherein the radical is generated by transporting plasma generated by high-frequency discharge downstream. 20. The method according to claim 18, wherein the electron supply method is a triode, hot filament, or field emission type electron gun. 21. The method according to claim 18, wherein a magnetic filter is provided between the negative ion generation space and the processing space of the substrate to be processed to capture unnecessary electrons. 22. The method of manufacturing a semiconductor device according to claim 18, wherein a multi-pole magnetic field is provided in the negative ion generation space to prevent charged particles from diffusing to a wall. 23. The method according to claim 14, wherein the negative ions are accelerated to a predetermined energy by applying a DC voltage to at least one or more grid electrodes. 24. A positive DC voltage or a pulsed voltage is applied to a support for installing the substrate to be processed in a vacuum vessel, so that the negative ions are incident on the substrate with predetermined energy. 2. The method according to claim 1, wherein
5. The method for manufacturing a semiconductor device according to item 4. 25. The method according to claim 1, wherein a grid electrode to which a DC voltage is applied is placed on a support of the substrate to be processed, and secondary electrons emitted from the substrate to be processed are captured.
5. The method for manufacturing a semiconductor device according to item 4. 26. The negative ion according to claim 5, wherein the oxygen-free material constituting at least the inner surface of the plasma generating means and the transporting means is a material selected from AlN and SiC. Surface treatment device using 27. Surface treatment of a substrate to be treated by applying negative ions generated by the surface treatment apparatus using negative ions according to claim 1 to the substrate to be treated. A surface treatment method using negative ions.