JP4361078B2 - Insulating film formation method - Google Patents

Description

  The present invention can efficiently produce an insulating film excellent in various characteristics (for example, control of ultrathin film thickness, high cleanliness, etc.) (for example, a small footprint by performing various processes in one reaction chamber, The present invention relates to a manufacturing method (simplification of operability by performing various processes in reaction chambers having the same operation principle, suppression of cross-contamination between apparatuses, etc.). The method for producing an electronic device material of the present invention can be suitably used for forming a material for, for example, a semiconductor or a semiconductor device (for example, a material having a MOS type semiconductor structure having a gate insulating film having excellent characteristics). Is possible.

  The present invention is generally widely applicable to the manufacture of electronic device materials such as semiconductors, semiconductor devices, and liquid crystal devices. Here, for convenience of explanation, the background technology of semiconductor devices will be described as an example. .

  Various treatments such as formation of an insulating film including an oxide film, film formation by CVD, etching, and the like are performed on a base material for a semiconductor or electronic device material including silicon.

  It is no exaggeration to say that the recent high performance of semiconductor devices has developed on the miniaturization technology of the devices including transistors. At present, transistor miniaturization technology is being improved with the aim of achieving higher performance. With the recent demand for miniaturization and higher performance of semiconductor devices, the need for higher performance insulating films (for example, in terms of leakage current) has increased remarkably. Even in the case of a leakage current of a level that is not practically a problem in a conventional device having a relatively low degree of integration, in a device that has been miniaturized, highly integrated, and / or improved in performance in recent years. This may cause severe problems. In particular, low power consumption devices are essential for the development of portable electronic devices in the so-called ubiquitous society that has started in recent years (information society using electronic devices connected to networks anytime and anywhere). This is a very important issue.

Typically, for example, in developing a next-generation MOS transistor, as the miniaturization technology as described above progresses, the thinning of the gate insulating film is approaching the limit, and a big problem to be overcome has appeared. . That is, as a process technology, it is possible to reduce the silicon oxide film (SiO ₂ ) currently used as a gate insulating film to the limit (1 to 2 atomic layer level), but the film thickness is 2 nm or less. In the case of the conversion, the leakage current due to the direct tunnel due to the quantum effect increases exponentially, and the power consumption increases.

  Currently, the IT (information technology) market is moving from fixed electronic devices (devices that supply power from outlets) represented by desktop personal computers and home phones to a “ubiquitous network society” that allows access to the Internet, etc. anytime and anywhere. Is trying to achieve the transformation. Accordingly, in the very near future, mobile terminals such as mobile phones and car navigation systems will become mainstream. Such a portable terminal is required to be a high-performance device itself, but at the same time, it has a small size, a light weight, and a function that can withstand long-term use that are not so necessary for the above-mentioned fixed device. It is assumed that Therefore, in mobile terminals, it is extremely important to reduce power consumption while achieving higher performance.

  Typically, for example, when developing a next-generation MOS transistor, if the miniaturization of a high-performance silicon LSI is pursued, there is a problem that leakage current increases and power consumption also increases. Therefore, in order to reduce power consumption while pursuing performance, it is necessary to improve the transistor characteristics without increasing the gate leakage current of the MOS transistor.

  In order to achieve both such miniaturization and improvement in characteristics, it is indispensable to form a high-quality and thin insulating film (for example, a film thickness of 15 A; about angstrom or less).

  However, it is very difficult to form a high-quality and thin insulating film. For example, when such an insulating film is formed by a conventional thermal oxidation method or CVD (Chemical Vapor Deposition) method, either the film quality or the film thickness is insufficient.

  An object of the present invention is to provide a method for forming a thin insulating film on a substrate for electronic devices, which has solved the above-mentioned drawbacks of the prior art.

  Another object of the present invention is for an electronic device capable of providing an insulating film excellent in both film quality and film thickness, which can be suitably subjected to subsequent processing (film formation by CVD, etching, etc.). An object of the present invention is to provide a method for forming a thin insulating film on a substrate surface.

  Still another object of the present invention is to perform various processes related to the formation of the insulating film using the same operating principle, thereby simplifying the device shape and efficiently forming an insulating film having excellent characteristics. There is.

  As a result of earnest research, the present inventor can form an insulating film by using a method capable of performing not only one process with a conventional apparatus but also various processes with one apparatus. It has been found that it is extremely effective for achieving the above objective.

  The method for forming an insulating film on the surface of an electronic device substrate according to the present invention is based on the above knowledge, and more specifically, in the process of forming an insulating film on the substrate for electronic device, the insulating film included in the step Two or more steps for controlling the characteristics are performed under the same operation principle.

  In the present invention, for example, a substrate for an electronic device is irradiated with plasma using a processing gas containing at least a rare gas, or a similar plasma is oxidized or nitrided by containing oxygen or nitrogen. The thickness of the insulating film can be reduced by including at least hydrogen in the same plasma in the insulating film containing oxygen atoms including the oxide film.

  According to the method for forming an insulating film of the present invention having the above-described configuration, for example, after forming a film having an arbitrary thickness with emphasis on film quality, the film is thinned by a specific plasma treatment to thereby form an arbitrary film thickness. This insulating film can be easily obtained.

  The present invention includes, for example, the following aspects.

  [1] In a process for forming an insulating film on a substrate for electronic devices, two or more steps for controlling insulating film characteristics included in the step are performed under the same operating principle. A method for forming a surface insulating film.

  [2] The process performed under the same operating principle is two or more processes selected from the group consisting of cleaning, oxidation, nitriding, and etching of the substrate surface and / or the insulating film. Of forming an insulating film.

  [3] The method for forming an insulating film according to [1] or [2], wherein the electronic device substrate is a semiconductor material.

  [4] The method for forming an insulating film according to any one of [1] to [3], wherein the base material for an electronic device is a substrate mainly composed of single crystal silicon.

  [5] The method for forming an insulating film according to any one of [1] to [4], wherein the operation principle includes plasma based on a processing gas including at least a rare gas.

  [6] The insulating film forming method according to [5], wherein the plasma is plasma based on microwave irradiation via a planar antenna member (slot plane antenna).

  [7] Formation of the insulating film according to any one of [1] to [6], wherein the process includes a cleaning step, and the cleaning step includes a plasma-based process based on a processing gas including at least a rare gas. Method.

  [8] The method for forming an insulating film according to [7], wherein the cleaning step includes a plasma treatment based on a treatment gas containing at least a rare gas and a hydrogen gas.

  [9] The insulating film according to any one of [1] to [8], wherein the process includes an oxidation step, and the oxidation step includes a plasma treatment based on a processing gas containing at least a rare gas and oxygen. Forming method.

  [10] The insulating film according to any one of [1] to [9], wherein the process includes a nitriding step, and the nitriding step includes plasma processing based on a processing gas containing at least a rare gas and nitrogen. Forming method.

  [11] The insulating film according to any one of [1] to [9], wherein the process includes an etching step, and the etching step includes a plasma treatment based on a processing gas containing at least a rare gas and hydrogen. Forming method.

  [12] The method for forming an insulating film according to [2], wherein two or more steps selected from the group consisting of cleaning, oxidation, nitriding, and etching of the substrate surface and / or the insulating film are performed in the same container. .

  [13] The method for forming an insulating film according to any one of [1] to [12], wherein the insulating film formed by the process is used as a base insulating film of a CVD (chemical vapor deposition) insulating film.

  [14] The method for forming an insulating film according to any one of [1] to [13], wherein the insulating film is an insulating film containing a High-k (high dielectric constant) material.

  [15] Two or more steps selected from the group consisting of cleaning, oxidation, nitriding, and etching of the substrate surface and / or the insulating film are performed by exposing the substrate surface and / or the insulating film to the atmosphere (atmospheric release). The method for forming an insulating film according to [2], which is performed while avoiding the above.

  As described above, according to the present invention, an insulating film excellent in various characteristics (for example, control of the thickness of an ultrathin film, high cleanliness, etc.) can be efficiently performed (for example, various processes are performed in one reaction chamber). Small footprint, simplified operability by performing various processes in a reaction chamber of the same operating principle, and suppression of cross-contamination between devices).

  Hereinafter, the present invention will be described more specifically with reference to the drawings as necessary. In the following description, “parts” and “%” representing the quantity ratio are based on mass unless otherwise specified.

(Method of forming insulating film)
In the present invention, the substrate for an electronic device is irradiated with plasma using a processing gas containing at least a rare gas, or the same plasma is oxidized or nitrided by containing oxygen or nitrogen. In addition, an insulating film containing oxygen atoms such as an oxide film is extremely thin by arbitrarily combining two or more processes such as reducing the thickness of the insulating film by including at least hydrogen in the same plasma (15A In the following, an insulating film can be formed. The target of application of the method for forming an insulating film of the present invention is not particularly limited, but the present invention has a surface particularly suitable for film formation of a high dielectric constant (High-k) material that is sensitive to film formation conditions, for example. Give a thin insulating film.

(Insulating film to be formed)
The composition, thickness, formation method, and characteristics of the insulating film that can be formed by the present invention are as follows.
Composition: oxide film, oxynitride film, nitride film Formation method: one or more processes of cleaning, oxidation, nitriding, and thinning on an electronic substrate in a single container using plasma containing at least a rare gas Is given. Alternatively, plasma including at least a rare gas formed by the same operation principle is generated in a plurality of containers, and cleaning, oxidation, nitriding, and thinning processes are performed on the electronic substrate.
Thickness: Physical thin film 5A-20A

(Evaluation of film quality and film thickness)
The film quality and the degree of film thickness of the thin insulating film obtained by the present invention can be suitably evaluated by, for example, actually forming a high-k material on the surface. Whether or not a high-quality high-k material film is obtained at this time is determined by, for example, a standard MOS semiconductor as described in the literature (physics of VLSI devices, Masayoshi Kishino, Mitsasa Koyanagi, Maruzen P62 to P63). By forming the structure and evaluating the characteristics of the MOS, the characteristics of the insulating film itself can be evaluated. This is because in such a standard MOS structure, the characteristics of the insulating film constituting the structure have a strong influence on the MOS characteristics.

  As the formation of such a MOS structure, for example, a MOS capacitor including the High-k material film can be formed under the conditions of Example 1 described later. As described above, when a MOS capacitor including a high-k material film is formed under the conditions of Example 1, in the present invention, the following (1) flat band characteristics or (2) leakage characteristics (more preferably , Both of these are preferably obtained.

(1) Preferred flat band characteristics: within ± 50 mV compared to thermal oxide film (2) Leakage characteristics: 1 digit or less reduction compared to thermal oxide film

(Combination with later processing)
The thin insulating film obtained by the insulating film forming method of the present invention is suitable for various subsequent processes. Such “post-treatment” is not particularly limited, and may be various treatments such as formation of an oxide film, film formation by CVD, etching, and the like. Since the method for forming an insulating film of the present invention can be performed at a low temperature, the subsequent treatment is also combined with a treatment under a temperature condition of a relatively low temperature (preferably 600 ° C. or less, more preferably 500 ° C. or less). It is particularly effective. The reason is that by using the present invention, it is possible to form an oxide film, which is one of the processes that require the highest temperature in the device manufacturing process, at a low temperature, so a high thermal history is avoided. This is because device fabrication is possible.

(Electronic device substrate)
The substrate for electronic devices that can be used in the present invention is not particularly limited, and can be appropriately selected from one or a combination of two or more known substrates for electronic devices. Examples of such electronic device base materials include semiconductor materials and liquid crystal device materials. Examples of the semiconductor material include a material mainly composed of single crystal silicon and a material mainly composed of silicon germanium.

(Processing gas)
The processing gas that can be used in the present invention is not particularly limited as long as it contains at least a rare gas, and may be appropriately selected from one or a combination of two or more known processing gases that can be used for electronic device manufacturing. Is possible. Examples of such processing gas (rare gas) include Ar, He, Kr, Xe, O ₂ , N ₂ , H ₂ , and NH ₃ .

(Processing gas conditions)
In forming the insulating film of the present invention, the following conditions can be preferably used from the viewpoint of the characteristics of the thin insulating film to be obtained.

  Noble gas (for example, Kr, Ar, He or Xe): 500 to 3000 sccm, more preferably 1000 to 2000 sccm,

In the cleaning step, hydrogen gas can be further added with a processing gas containing at least a rare gas. The flow rate of hydrogen gas is H ₂ : 0 to 100 sccm, more preferably 0 to 50 sccm.

In the oxidation step, a processing gas containing at least a rare gas and oxygen, and an oxygen gas flow rate is O ₂ : 10 to 500 sccm, more preferably 10 to 200 sccm.

In the nitriding step, the processing gas contains at least a rare gas and nitrogen, and the nitrogen gas flow rate is N ₂ : 3 to 300 sccm, more preferably 20 to 200 sccm.

In the etching step, the processing gas contains at least a rare gas and hydrogen, and the hydrogen gas flow rate is H ₂ : 0 to 100 sccm, more preferably 0 to 50 sccm.
Temperature: Room temperature 25 ° C to 500 ° C, more preferably 250 to 500 ° C, particularly preferably 250 to 400 ° C
Pressure: 3 to 500 Pa, more preferably 7 to 260 Pa,
Microwave: 1 to 5 W / cm ² , more preferably ^{2 to 4} W / cm ² , particularly preferably ^{2 to 3} W / cm ²

  The plasma that can be used in the present invention is not particularly limited, but it is preferable to use a plasma having a relatively low electron temperature and a high density from the viewpoint that a uniform thin film can be easily obtained.

(Preferred plasma)
The characteristics of plasma that can be suitably used in the present invention are as follows.
Electron temperature: 0.5 to 2.0 eV
Density: 1E10-5E12 / cm ³
Plasma density uniformity: ± 10%

(Flat antenna member)
In the method for forming an insulating film of the present invention, it is preferable to form a plasma having a low electron temperature and a high density by irradiating microwaves through a planar antenna member having a plurality of slots. In the present invention, since an oxynitride film is formed using plasma having such excellent characteristics, a process with low plasma damage and high reactivity at low temperatures becomes possible. In the present invention, there is an advantage that it is easy to form a thin insulating film more suitably by irradiating microwaves through a planar antenna member (compared to the case of using conventional plasma). can get.

  According to the present invention, a thin insulating film can be formed. Therefore, by forming another layer (for example, another insulating layer) on the thinned insulating film, it becomes easy to form a structure of a semiconductor device having excellent characteristics. The insulating film thinned according to the present invention is particularly suitable for forming a high-k material film on the surface of the thinned insulating film.

(Hi-k material)
The high-k material that can be used in the present invention is not particularly limited, but from the viewpoint of increasing the physical film thickness, a k (relative dielectric constant) value of 7 or more, more preferably 10 or more is preferable.

Examples of such high-k materials include Al ₂ O ₃ , ZrO ₂ , HfO ₂ , Ta ₂ O ₅ , and silicates such as ZrSiO and HfSiO; 1 selected from the group consisting of aluminates such as ZrAlO Two or more can be suitably used.

(Processing in the same container)
“In the same container” described below means that after a certain process, the substrate to be processed is subjected to subsequent processing without passing through the wall of the container. When a so-called “cluster” structure formed by combining a plurality of containers is used, if there is movement between different containers constituting the cluster, it is not “in the same container” according to the present invention.

  In the present invention, a plurality of processes are continuously performed in a reaction chamber having the same principle without exposing the base material (silicon substrate or the like) to be processed to the atmosphere in the “same container”. For example, the footprint can be reduced by performing all the steps in one reaction chamber. Even when processing each process in a separate reaction chamber, the reaction chambers with the same operating principle are arranged, so the gas piping and operation panel can be made the same, realizing excellent maintenance and operability. it can. Furthermore, since the same apparatus is used, there is a low possibility of contamination between apparatuses, and even in a cluster configuration having a plurality of reaction chambers, the processing order can be changed variously. When this method is used, a gate insulating film having various characteristics can be manufactured.

  Although an oxide film or oxynitride film manufactured using the present invention can be used as a gate insulating film as it is, an ultra-thin (-10 A; angstrom) oxide film or oxynitride is used according to the present invention. By forming a film and forming a material having a high dielectric constant such as High-k on the film, the interface characteristics, for example, the carrier mobility of the transistor, are higher than when a gate insulating film is formed using the High-k material alone. It is also possible to produce a stacked gate insulating film structure (gate stack structure) having a high height.

(Suitable characteristics of semiconductor structure)
The range to which the method for forming an insulating film of the present invention should be applied is not particularly limited, but the cleaned surface that can be formed according to the present invention is a gate insulating film having a MOS structure thereon (for example, a gate containing a High-k material). When forming the insulating film, it can be used particularly suitably.

(Suitable characteristics of MOS semiconductor structure)
An extremely thin and high-quality insulating film that can be formed on a substrate cleaned by the present invention can be particularly suitably used as an insulating film of a semiconductor device (particularly a gate insulating film of a MOS semiconductor structure).

  According to the present invention, a MOS semiconductor structure having suitable characteristics as described below can be easily manufactured. In evaluating the characteristics of the oxynitride film formed according to the present invention, for example, a standard MOS semiconductor structure as described in the literature (Physics of VLSI devices, Masayoshi Kishino, Mitsumasa Koyanagi, Maruzen P62-P63) And evaluating the characteristics of the MOS can replace the characteristics evaluation of the oxynitride film itself. This is because in such a standard MOS structure, the characteristics of the oxynitride film constituting the structure strongly influence the MOS characteristics.

(One aspect of manufacturing apparatus)
Hereinafter, a preferred embodiment of the forming method of the present invention will be described.

  First, as an example of the structure of a semiconductor device that can be manufactured by the method for manufacturing an electronic device material of the present invention, a semiconductor device having a MOS structure having a gate insulating film as an insulating film will be described with reference to FIG.

  Referring to FIG. 1A, in FIG. 1A, reference numeral 1 is a silicon substrate, 11 is a field oxide film, 2 is a gate insulating film, and 13 is a gate electrode. As described above, according to the forming method of the present invention, it is possible to form the gate insulating film 2 that is extremely thin and of good quality. As shown in FIG. 1B, the gate insulating film 2 is made of a high quality insulating film formed at the interface with the silicon substrate 1. For example, the oxide film 2 is about 2.5 nm thick.

In this example, the high-quality oxide film 2 is formed on a substrate to be processed mainly composed of Si via a planar antenna member having a plurality of slots in the presence of a processing gas containing O ₂ and a rare gas. It is preferable that a plasma is formed by irradiating a wave, and a silicon oxide film (hereinafter referred to as “SiO ₂ film”) formed on the surface of the substrate to be processed by using the plasma. When such a SiO ₂ film is used, as will be described later, the interface characteristics between phases (for example, interface states) are good, and it is easy to obtain good gate leakage characteristics when a MOS structure is used. There is a feature.

  In the embodiment shown in FIG. 1, a gate electrode 13 containing silicon (polysilicon or amorphous silicon) as a main component is further formed on the nitrided surface of the silicon oxide film 2.

(One aspect of manufacturing method)
Next, a method for manufacturing such an electronic device material in which the silicon oxide film 2 and the gate electrode 13 are disposed thereon will be described.

  FIG. 2 is a schematic view (schematic plan view) showing an example of the entire configuration of a semiconductor manufacturing apparatus 30 for carrying out the method for manufacturing an electronic device material of the present invention.

  As shown in FIG. 2, a transfer chamber 31 for transferring the wafer W (FIG. 2) is disposed substantially at the center of the semiconductor manufacturing apparatus 30, and surrounds the periphery of the transfer chamber 31. Plasma processing units 32 and 33 for performing various processes on the wafer, two load lock units 34 and 35 for performing communication / blocking operations between the processing chambers, and a heating unit for performing various heating operations 36 and a heating reaction furnace 47 for performing various heat treatments on the wafer. The heating reaction furnace 47 may be provided separately from the semiconductor manufacturing apparatus 30.

  Next to the load lock units 34 and 35, a preliminary cooling unit 45 and a cooling unit 46 for performing various preliminary cooling or cooling operations are respectively arranged.

  Inside the transfer chamber 31, transfer arms 37 and 38 are disposed, and the wafer W (FIG. 2) can be transferred between the units 32 to 36.

  Loader arms 41 and 42 are disposed on the front side of the load lock units 34 and 35 in the drawing. These loader arms 41 and 42 can move wafers W in and out of four cassettes 44 set on a cassette stage 43 disposed on the front side thereof.

  Note that two plasma processing units of the same type are set in parallel as the plasma processing units 32 and 33 in FIG.

  Further, both the plasma processing unit 32 and the unit 33 can be replaced with a single chamber type CVD processing unit, and one or two single chamber type CVD processing units are provided at the positions of the plasma processing units 32 and 33. It is also possible to set.

In the case of two plasma treatments, for example, after the SiO ₂ film is formed in the processing unit 32, a method of surface nitriding the SiO ₂ film in the processing unit 33 may be performed. _Two- film formation and surface nitridation of the SiO ₂ film may be performed. Alternatively, the surface nitridation can be performed in parallel by the processing units 32 and 33 after the SiO ₂ film is formed by another apparatus.

(One aspect of gate green film deposition)
FIG. 3 is a schematic sectional view in the vertical direction of a plasma processing unit 32 (33) that can be used for forming the gate green film 2.

Referring to FIG. 3, reference numeral 50 is a vacuum vessel made of, for example, aluminum. An opening 51 larger than the substrate (for example, the wafer W) is formed on the upper surface of the vacuum container 50, and a flat made of a dielectric material such as quartz or aluminum oxide so as to close the opening 51. A cylindrical top plate 54 is provided. On the side wall on the upper side of the vacuum vessel 50, which is the lower surface of the top plate 54, for example, gas supply pipes 72 are provided at 16 positions arranged uniformly along the circumferential direction. A processing gas containing one or more selected from O ₂ , rare gas, N _2, H _2, etc. is supplied uniformly in the vicinity of the plasma region P of the vacuum vessel 50.

  On the outside of the top plate 54, a high frequency power supply unit is formed via a planar antenna member having a plurality of slots, for example, a slot plane antenna (SPA) 60 formed of a copper plate, for example, 2.45 GHz micro A waveguide 63 connected to a microwave power source 61 that generates a wave is provided. The waveguide 63 includes a flat plate-shaped waveguide 63A having a lower edge connected to the SPA 60, a cylindrical waveguide 63B having one end connected to the upper surface of the plate-shaped waveguide 63A, and the cylindrical waveguide. A coaxial waveguide converter 63C connected to the upper surface of the tube 63B, and a rectangular waveguide having one end connected perpendicularly to the side surface of the coaxial waveguide converter 63C and the other end connected to the microwave power source 61. 63D is combined.

  Here, in the present invention, UHF and microwaves are referred to as a high frequency region. That is, the high-frequency power supplied from the high-frequency power supply unit is 300 MHz to 2500 MHz including UHF of 300 MHz or higher and microwaves of 1 GHz or higher, and the plasma generated by these high-frequency power is called high-frequency plasma. .

  Inside the cylindrical waveguide 63B, one end side of the shaft portion 62 made of a conductive material is connected to substantially the center of the upper surface of the SPA 60, and the other end side is connected to the upper surface of the cylindrical waveguide 63B. Thus, the waveguide 63B is configured as a coaxial waveguide.

  A mounting table 52 for the wafer W is provided in the vacuum container 50 so as to face the top plate 54. The mounting table 52 incorporates a temperature control unit (not shown) so that the mounting table 52 functions as a heat plate. Further, one end side of the exhaust pipe 53 is connected to the bottom of the vacuum vessel 50, and the other end side of the exhaust pipe 53 is connected to the vacuum pump 55.

(One aspect of SPA)
FIG. 4 is a schematic plan view showing an example of SPA 60 that can be used in the electronic device material manufacturing apparatus of the present invention.

  As shown in FIG. 4, in the SPA 60, a plurality of slots 60a, 60a,... Are formed concentrically on the surface. Each slot 60a is a substantially rectangular through groove, and adjacent slots are arranged so as to be orthogonal to each other to form the letter “T” of the alphabet. The length and arrangement interval of the slots 60 a are determined according to the wavelength of the microwave generated from the microwave power supply unit 61.

(One aspect of heating reactor)
FIG. 5 is a schematic cross-sectional view in the vertical direction showing an example of a heating reactor 47 that can be used in the electronic device material manufacturing apparatus of the present invention.

  As shown in FIG. 5, the processing chamber 82 of the heating reactor 47 is formed in an airtight structure with aluminum or the like, for example. Although omitted in FIG. 5, the processing chamber 82 includes a heating mechanism and a cooling mechanism.

  As shown in FIG. 5, the processing chamber 82 is connected to a gas introduction pipe 83 that introduces gas into the upper center, and the inside of the processing chamber 82 and the inside of the gas introduction pipe 83 are communicated with each other. The gas introduction pipe 83 is connected to a gas supply source 84. A gas is supplied from the gas supply source 84 to the gas introduction pipe 83, and the gas is introduced into the processing chamber 82 via the gas introduction pipe 83. As this gas, for example, various gases (electrode forming gas) such as silane, which are raw materials for gate electrode formation, can be used, and an inert gas can also be used as a carrier gas, if necessary.

  A gas exhaust pipe 85 for exhausting the gas in the process chamber 82 is connected to the lower part of the process chamber 82, and the gas exhaust pipe 85 is connected to an exhaust means (not shown) such as a vacuum pump. By this exhaust means, the gas in the processing chamber 82 is exhausted from the gas exhaust pipe 85, and the processing chamber 82 is set to a desired pressure.

  In addition, a mounting table 87 on which the wafer W is mounted is disposed below the processing chamber 82.

  In the embodiment shown in FIG. 5, the wafer W is mounted on the mounting table 87 by an electrostatic chuck (not shown) having the same diameter as that of the wafer W. The mounting table 87 is provided with a heat source means (not shown), and has a structure capable of adjusting the processing surface of the wafer W mounted on the mounting table 87 to a desired temperature.

  The mounting table 87 has a mechanism capable of rotating the mounted wafer W as necessary.

  In FIG. 5, an opening 82a for taking in and out the wafer W is provided on the wall surface of the processing chamber 82 on the right side of the mounting table 87. The opening and closing of the opening 82a moves the gate valve 98 in the vertical direction in the drawing. Is done. In FIG. 5, a transfer arm (not shown) for transferring the wafer W is provided adjacent to the right side of the gate valve 98, and the transfer arm enters and exits the processing chamber 82 through the opening 82a. The wafer W is placed on the substrate 87 and the processed wafer W is unloaded from the processing chamber 82.

  A shower head 88 as a shower member is disposed above the mounting table 87. The shower head 88 is formed so as to partition a space between the mounting table 87 and the gas introduction pipe 83, and is made of, for example, aluminum.

  The shower head 88 is formed so that the gas outlet 83a of the gas introduction pipe 83 is located at the upper center of the shower head 88, and the gas is introduced into the processing chamber 82 through the gas supply hole 89 provided at the lower part of the shower head 88. Yes.

(Insulation film formation mode)
Next, a preferred example of a method for forming an insulating film made of the gate insulating film 2 on the wafer W using the above-described apparatus will be described.

  FIG. 7 is a flowchart showing an example of the flow of each step (after the cleaning process) in the method of the present invention.

  Referring to FIG. 7, first, field oxide film 11 (FIG. 1A) is formed on the surface of wafer W in the preceding step. The oxide film 11 can also be formed by plasma processing (for example, using the above-described SPA or the like).

  Next, a gate valve (not shown) provided on the side wall of the vacuum vessel 50 in the plasma processing unit 32 (FIG. 2) is opened, and the field oxide film 11 is formed on the surface of the silicon substrate 1 by the transfer arms 37 and 38. The wafer W is mounted on the mounting table 52 (FIG. 3).

  Subsequently, after closing the gate valve and sealing the inside, the internal atmosphere is evacuated by the vacuum pump 55 through the exhaust pipe 53 and evacuated to a predetermined degree of vacuum, and maintained at a predetermined pressure. On the other hand, a microwave of 1.80 GHz (2200 W), for example, is generated from the microwave power supply unit 61, and this microwave is guided by a waveguide and introduced into the vacuum vessel 50 through the SPA 60 and the top plate 54, whereby a vacuum is generated. High-frequency plasma is generated in the upper plasma region P in the container 50.

  Here, the microwave is transmitted through the rectangular waveguide 63D in the rectangular mode, converted from the rectangular mode to the circular mode by the coaxial waveguide converter 63C, and transmitted through the cylindrical coaxial waveguide 63B in the circular mode. The flat waveguide 63A is transmitted in the radial direction, is radiated from the slot 60a of the SPA 60, passes through the top plate 54, and is introduced into the vacuum vessel 50. At this time, since microwaves are used, plasma with a high density and low electrons is generated, and since microwaves are radiated from many slots 60a of the SPA 60, the plasma has a uniform distribution.

Next, while adjusting the temperature of the mounting table 52 and heating the wafer W to, for example, 400 ° C., a rare gas such as krypton or argon, which is a processing gas for forming an oxide film, and O ₂ gas are supplied from the gas supply pipe 72. The first step (formation of an oxide film) is performed by introducing them at a flow rate of 2000 sccm and 200 sccm, respectively.

In this step, the introduced processing gas is activated (radicalized) by the plasma flow generated in the plasma processing unit 32, and this plasma causes the silicon substrate 1 as shown in the schematic sectional view of FIG. Is oxidized to form an oxide film (SiO ₂ film) 2. Thus, this oxidation treatment is performed for 40 seconds, for example, to form a gate oxide film or a base oxide film for gate oxynitride film (base SiO ₂ film) 2 having a thickness of 2.5 nm.

  Next, the gate valve (not shown) is opened, the transfer arms 37 and 38 (FIG. 2) are moved into the vacuum vessel 50, and the wafer W on the mounting table 52 is received. The transfer arms 37 and 38 take the wafer W out of the plasma processing unit 32 and then set it on a mounting table in the adjacent plasma processing unit 33 (step 2). In some cases, the gate oxide film may be moved to the thermal reactor 47 without being nitrided.

(Aspect of formation of nitride-containing layer)
Next, if necessary, surface nitridation is performed on the wafer W in the plasma processing unit 33, and the nitride-containing layer 21 (FIG. 7) is formed on the surface of the previously formed base oxide film (base SiO ₂ ) 2. (B)) is formed.

In this surface nitriding treatment, for example, in the vacuum vessel 50, the wafer temperature is, for example, 400 ° C., and the process pressure is, for example, 66.7 Pa (500 mTorr). , N ₂ gas are introduced at flow rates of 1000 sccm and 40 sccm, respectively.

On the other hand, for example, a microwave of ² W / cm ² is generated from the microwave power source 61, and the microwave is guided by the waveguide and introduced into the vacuum vessel 50 through the SPA 60 b and the top plate 54, thereby High-frequency plasma is generated in the upper plasma region P in the vacuum vessel 50.

In this step (surface nitridation), the introduced gas is turned into plasma and nitrogen radicals are formed. The nitrogen radicals react on the SiO ₂ film on the upper surface of the wafer W, and nitride the SiO ₂ film surface in a relatively short time. In this way, as shown in FIG. 7B, the nitrogen-containing layer 21 is formed on the surface of the base oxide film (base SiO ₂ film) 2 on the wafer W.

  By performing this nitriding treatment for 20 seconds, for example, a gate oxynitride film (oxynitride film) having a converted film thickness of about 2 nm can be formed.

(Mode of gate electrode formation)
Next, the gate electrode 13 (FIG. 1A) is formed on the SiO ₂ film on the wafer W or the oxynitride film obtained by nitriding the base SiO ₂ film. In order to form the gate electrode 13, the wafer W on which the gate oxide film or the gate oxynitride film is formed is taken out from the plasma processing unit 32 or 33, and is once taken out to the transfer chamber 31 (FIG. 2) side. It is accommodated in the heating reaction furnace 47 later (step 4). In the heating reactor 47, the wafer W is heated under predetermined processing conditions to form a predetermined gate electrode 13 on the gate oxide film or gate oxynitride film.

  At this time, processing conditions can be selected according to the type of gate electrode 13 to be formed.

That is, when forming the gate electrode 13 made of polysilicon, for example, SiH ₄ is used as a processing gas (electrode forming gas), a pressure of 20 to 33 Pa (150 to 250 mTorr), and a temperature condition of 570 to 690 ° C. Process below.

When the gate electrode 13 made of amorphous silicon is formed, for example, SiH ₄ is used as a processing gas (electrode forming gas), a pressure of 20 to 67 Pa (150 to 500 mTorr), and a temperature condition of 520 to 570 ° C. Process below.

Further, when the gate electrode 13 made of SiGe is formed, for example, a mixed gas of GeH ₄ / SiH ₄ = 10/90 to 60/40% is used, a pressure of 20 to 60 Pa, and a temperature condition of 460 to 560 ° C. Process below.

(Quality of oxide film)
In the first step described above, when forming the gate oxide film or the base oxide film for the gate oxynitride film, the planar antenna member having a plurality of slots in the wafer W containing Si as a main component in the presence of a processing gas. A plasma containing oxygen (O ₂ ) and a rare gas is formed by irradiating microwaves through (SPA), and an oxide film is formed on the surface of the substrate to be processed using this plasma. And the film quality can be controlled successfully.

  Further, by performing clustering as shown in FIG. 2, it becomes possible to avoid exposure to the atmosphere between the formation of the gate oxide film and the gate oxynitride film and the formation of the gate electrode, thereby further improving the interface characteristics. Improvement is possible.

  Hereinafter, the present invention will be described more specifically with reference to examples.

Example 1
Devices for performing various evaluations were formed by the following methods.

(1): Substrate A P-type silicon substrate was used as the substrate, and one with a specific resistance of 8-12 Ωcm and a plane orientation (100) was used. A 500 A (angstrom) sacrificial oxide film is formed on the silicon substrate surface by thermal oxidation.

(2): Cleaning before gate oxidation APM (mixture of ammonia, hydrogen peroxide, and pure water), HPM (mixture of hydrochloric acid, hydrogen peroxide, and pure water) and DHF (mixture of hydrofluoric acid and pure water) The sacrificial oxide film and the contaminating elements (metal, organic matter, particles) were removed by RCA cleaning combined with the above.

(3): Plasma treatment before oxidation After the treatment (2) above, SPA plasma treatment was performed on the substrate. The processing conditions are as follows. After the wafer was transferred to a vacuum (back pressure 1 × 10 ⁻⁴ Pa or less) reaction processing chamber, the substrate temperature was 400 ° C., the rare gas (eg, Ar gas) was 1000 sccm, and the pressure was maintained at 7 Pa to 133 Pa (50 mTorr to 1 Torr). . A rare gas plasma was generated by irradiating a microwave of ² to 3 W / cm ² through a planar antenna member (SPA) having a plurality of slots in the atmosphere, and plasma treatment was performed on the substrate surface. In some cases, pretreatment for oxidation by hydrogen plasma may be performed by adding 5 to 30 sccm of hydrogen in the rare gas.

(4): Plasma oxidation process An oxide film was formed on the silicon substrate that had been subjected to the treatment (3) by the following method. Perform the following process without exposing the silicon substrate treated in (3) to the atmosphere (for example, use a vacuum transfer system that performs processing in the same reaction chamber to prevent exposure to the atmosphere. By performing the treatment in another reaction chamber, etc., the oxidation treatment can be performed while maintaining the organic matter contamination removal and natural oxide film removal effects obtained by the treatment (3) optimally. A rare gas and oxygen were allowed to flow at 1000 to 2000 sccm and 50 to 500 sccm, respectively, on a silicon substrate heated to 400 ° C., and the pressure was maintained at 13 Pa to 133 Pa (100 mTorr to 1000 mTorr). A plasma containing oxygen and a rare gas is formed by irradiating a microwave of ² to 3 W / cm ² through a planar antenna member (SPA) having a plurality of slots in the atmosphere. An SiO ₂ film was formed on the substrate. Further, the film thickness was controlled by changing the processing conditions including the processing time.

(5): Plasma nitriding process Nitriding was performed on the oxide film subjected to the above processing (4) by the following method. The following process is performed on the oxide film subjected to the treatment (4) without exposing it to the atmosphere (for example, using a vacuum transfer system that performs processing in the same reaction chamber to prevent exposure to the atmosphere). Thus, the nitriding treatment can be performed while suppressing the organic matter contamination on the upper portion of the oxide film obtained by the treatment (4) and the increase in the natural oxide film. A rare gas and nitrogen were allowed to flow at 500 to 2000 sccm and 4 to 500 sccm, respectively, on a silicon substrate heated to 400 ° C., and the pressure was maintained at 3 Pa to 133 Pa (20 mTorr to 1000 mTorr). A plasma containing nitrogen and a rare gas is formed by irradiating a microwave of 3 W / cm ² through a planar antenna member (SPA) having a plurality of slots in the atmosphere, and this plasma is used to form a plasma on the substrate. An oxynitride film (SiON film) was formed.

(6): Thinning with hydrogen plasma and recovery of Vfb shift An annealing treatment with hydrogen plasma was performed on the oxynitride film subjected to the treatment of (5) by the following method. The following process is performed on the oxynitride film that has been subjected to the treatment of (5) without performing exposure to the atmosphere (for example, processing is performed in the same reaction chamber using a vacuum transfer system, and exposure to the atmosphere is performed). In other reaction chambers, the hydrogen plasma annealing treatment can be performed while suppressing organic contamination and an increase in natural oxide film on the oxynitride film obtained by the treatment (5). I can do it. A rare gas and hydrogen were allowed to flow at 500 to 2000 sccm and 4 to 500 sccm, respectively, on a silicon substrate heated to 400 ° C., and the pressure was maintained at 3 Pa to 133 Pa (20 mTorr to 1000 mTorr). A plasma containing hydrogen and a rare gas is formed by irradiating a microwave of ² to 3 W / cm ² through a planar antenna member (SPA) having a plurality of slots in the atmosphere. A hydrogen plasma annealing process was performed on the nitride film. The SIMS analysis sample in FIG. 11 is obtained by stopping the processing in this step and performing the analysis.

(7): Polysilicon film formation for gate electrode Polysilicon film was formed by CVD as a gate electrode on the oxynitride film formed in the above treatments (3) to (6). The silicon substrate on which the oxynitride film is formed is heated at 630 ° C., and 250 sccm of silane gas is introduced onto the substrate under a pressure of 33 Pa and held for 30 minutes, whereby the polysilicon film for an electrode having a thickness of 3000 A is formed on the SiO ₂ film. A film was formed.

(8): P (phosphorus) doping into polysilicon The silicon substrate fabricated in (7) above is heated to 875 ° C., and POCl ₃ gas, oxygen, and nitrogen are respectively applied to the substrate under normal pressure at 350 sccm, 200 sccm, and 20000 sccm. The polysilicon was doped with phosphorous by introducing and holding for 24 minutes.

(9): Patterning and gate etching Patterning is performed by lithography on the silicon substrate produced in (8) above, and the silicon substrate is placed in a chemical solution in a ratio of HF: HNO ₃ : H ₂ O = 1: 60: 60 for 3 minutes. By immersing, the unpatterned portion of the polysilicon was melted to fabricate a MOS capacitor.

Example 2
The measurement for the MOS capacitor obtained in Example 1 was performed by the following method. The CV and IV characteristics of a capacitor having a gate electrode area of 10,000 μm ² were evaluated. The CV characteristics were obtained by sweeping the gate voltage from about 0 V to -3 V and evaluating the capacitance at each voltage at a frequency of 100 KHz. The electrical film thickness and Vfb (flat band voltage) were calculated from the CV characteristics. Further, the IV characteristic was obtained by sweeping the gate voltage from 0 V to -5 V and evaluating the current value (leakage current value) flowing at each voltage. The leakage current value at the gate electrode voltage obtained by subtracting −0.4 V from Vfb obtained from CV measurement was calculated from the IV characteristics.

  FIG. 8 compares the leakage characteristics of the oxide film with and without the pre-plasma treatment. In order to show only the effect of the pre-plasma treatment, the oxide film used here is not subjected to nitridation and post-hydrogen treatment. The horizontal axis shows the electrical film thickness obtained from the CV characteristics, and the vertical axis shows the leakage current value at the gate voltage Vfb-0.4V (about -1.2V because Vfb is about -0.8V). As can be seen from FIG. 8, the leakage current value of the oxide film has been successfully reduced by performing the pre-plasma treatment.

  FIG. 9 is a comparison of the flat band characteristics of a SPA plasma oxide film that has been subjected to pre-plasma treatment and a thermal oxide film that is currently generally used in devices. The horizontal axis represents the electrical film thickness obtained from the CV characteristics, and the vertical axis represents the flat band voltage obtained from the CV characteristics. It is known that the flat band voltage greatly shifts in the negative direction when defects such as carrier traps exist at the film or interface. However, the pre-plasma-treated film is equivalent to the thermal oxide film (about -0.8V), and no deterioration of the flat band characteristics in this step was observed.

  FIG. 10a shows the change over time in the electrical thickness of the gate oxynitride film using a plurality of steps (multi-process) according to the present invention (change in electrical thickness for each step). The horizontal axis represents the processing time, and the vertical axis represents the electrical film thickness. It has succeeded in reducing the electrical film thickness by 0.8 to 1.5 A by performing nitriding treatment. Moreover, it has succeeded in further thinning by post-hydrogen treatment.

  FIG. 10b shows the change over time of the flat band voltage of the film similar to FIG. 9 (change of the flat band voltage in each step). The horizontal axis is the processing time, and the vertical axis is the flat band voltage. It is known that the flat band voltage is greatly shifted in the negative direction when defects such as carrier traps exist in the film or interface, but the film after the plasma hydrogen treatment shows the recovery of the flat band shift. This indicates that the film characteristics deteriorated by nitriding are recovered.

  It can be seen from FIG. 11 that the film thickness (thickness of the layer containing oxygen) is reduced by performing the hydrogen treatment. This is considered to be due to the reduction action by the hydrogen reactive species. By effectively using this process, it is possible to control (etching) the thinning of the region (-10A) that is difficult to control.

  As can be seen from FIGS. 10a and 10b, when the present invention is used, a plurality of steps can be continuously performed in a reaction chamber having the same principle without exposing the silicon substrate to the atmosphere. The footprint can be reduced by performing all processes in one reaction chamber. Even when processing each process in a separate reaction chamber, the reaction chambers with the same operating principle are arranged, so the gas piping and operation panel can be made the same, achieving excellent maintenance and operability. it can. Furthermore, since the same apparatus is used, there is a low possibility of contamination between apparatuses, and even in a cluster configuration having a plurality of reaction chambers, the processing order can be changed variously. When this method is used, a gate insulating film having various characteristics can be manufactured.

  In the above example, the oxynitride film manufactured using the present invention is used as a gate insulating film as it is, but an ultrathin (-10 A; angstrom) oxynitride film is formed using the present invention. Further, by depositing a material having a high dielectric constant such as High-k thereon, a layer having higher interface characteristics, for example, carrier mobility of the transistor than when a high-k material alone is used to form a gate insulating film. It is also possible to make a gate insulating film structure (gate stack structure).

Example 3
The manufacturing method of the logic device according to this aspect is roughly performed according to a flow such as “element isolation → MOS transistor fabrication → capacitance fabrication → interlayer insulating film formation and wiring”.

  In the following, the MOS transistor fabrication process including the process of the present invention will be described with reference to general examples of the fabrication of a MOS structure particularly deeply related to the present invention.

(1): Substrate A P-type or N-type silicon substrate is used as the substrate, and one having a specific resistance of 1 to 30 Ωcm and a plane orientation (100) is used. A method for manufacturing an NHOS transistor using a P-type silicon substrate will be described below.

  Depending on the purpose, element isolation processes such as STI and LOCOS and channel implantation are performed on the silicon substrate, and a sacrificial oxide film is formed on the surface of the silicon substrate on which the gate oxide film and gate insulating film are formed. (FIG. 12).

(2): Cleaning before forming gate oxide film (gate insulating film) Generally, APM (a mixture of ammonia, hydrogen peroxide, and pure water) and HPM (a mixture of hydrochloric acid, hydrogen peroxide, and pure water), and The sacrificial oxide film and the contaminating elements (metal, organic matter, particles) are removed by RCA cleaning combined with DHF (mixed solution of hydrofluoric acid and pure water). SPM (mixed solution of sulfuric acid and hydrogen peroxide solution), ozone water, FPM (mixed solution of hydrofluoric acid, hydrogen peroxide solution and pure water), hydrochloric acid solution (mixed solution of hydrochloric acid and pure water), organic as required Sometimes alkali or the like is used.

(3): Plasma treatment before base oxidation After the processing of (2), SPA plasma processing is performed on the substrate as a pre-process for forming the base oxide film. For example, the following processing conditions can be considered. After the wafer is transferred to a vacuum (back pressure 1 × 10 ⁻⁴ Pa or less) reaction processing chamber, the substrate temperature is 400 ° C., the rare gas (eg, Ar gas) is 1000 sccm, and the pressure is maintained at 7 Pa to 133 Pa (50 mTorr to 1000 mTorr). . A rare gas plasma is generated by irradiating a microwave of ² to 3 W / cm ² through a planar antenna member (SPA) having a plurality of slots in the atmosphere, and plasma treatment is performed on the substrate surface. Further, in some cases, by including 5 to 30 sccm of hydrogen in the mixed gas, an oxidation pretreatment by hydrogen plasma may be performed (FIG. 13).

(4): Formation of base oxide film An oxide film is formed on the silicon substrate subjected to the processing of (3) by the following method. By performing the following process (for example, processing in the same reaction chamber) without exposing the silicon substrate subjected to the process (3) to the atmosphere, the organic substance obtained by the process (3) The oxidation treatment can be performed while maintaining the contamination removal effect and the natural oxide film removal effect optimally. A rare gas and oxygen are allowed to flow at 1000 to 2000 sccm and 50 to 500 sccm, respectively, on the silicon substrate heated to 400 ° C., and the pressure is maintained at 13 Pa to 133 Pa (100 mTorr to 1000 mTorr). A plasma containing oxygen and a rare gas is formed by irradiating a microwave of ² to 3 W / cm ² through a planar antenna member (SPA) having a plurality of slots in the atmosphere. A SiO ₂ film is formed on the substrate. Further, the film thickness can be controlled by changing the processing conditions including the processing time (FIG. 14).

(5): Plasma nitriding process Nitriding is performed on the oxide film that has been subjected to the processing of (4) above by the following method. The following process is performed on the oxide film subjected to the treatment (4) without exposing it to the atmosphere (for example, using a vacuum transfer system that performs processing in the same reaction chamber to prevent exposure to the atmosphere). Thus, the nitriding treatment can be performed while suppressing the organic matter contamination on the upper portion of the oxide film obtained by the treatment (4) and the increase in the natural oxide film. A rare gas and nitrogen are allowed to flow at 500 to 2000 sccm and 4 to 500 sccm, respectively, on a silicon substrate heated to 400 ° C., and the pressure is maintained at 3 Pa to 133 Pa (20 mTorr to 1000 mTorr). A plasma containing nitrogen and a rare gas is formed by irradiating a microwave of ² to 3 W / cm ² through a planar antenna member (SPA) having a plurality of slots in the atmosphere, and using this plasma, a substrate is formed. An oxynitride film (SiON film) is formed thereon (FIG. 14).

(6): Thinning with hydrogen plasma and recovery of Vfb shift An annealing process with hydrogen plasma is performed on the oxynitride film subjected to the process (5) with the following method. The following process is performed on the oxynitride film that has been subjected to the treatment of (5) without performing exposure to the atmosphere (for example, processing is performed in the same reaction chamber using a vacuum transfer system, and exposure to the atmosphere is performed). By performing a hydrogen plasma annealing treatment while suppressing organic contamination and an increase in natural oxide film on the upper part of the oxynitride film obtained by the treatment (5) I can do it. A rare gas and hydrogen are allowed to flow at 500 to 2000 sccm and 4 to 500 sccm, respectively, on a silicon substrate heated to 400 ° C., and the pressure is maintained at 3 Pa to 133 Pa (20 mTorr to 1000 mTorr). A plasma containing hydrogen and a rare gas is formed by irradiating a microwave of ² to 3 W / cm ² through a planar antenna member (SPA) having a plurality of slots in the atmosphere. A hydrogen plasma annealing process is performed on the nitride film (FIG. 14).

(7): Formation of Hi-k gate insulating film A High-k material is formed on the base oxynitride film formed in (6) above. High-k gate insulating film forming methods are roughly classified into processes using CVD and processes using PVD. Here, the formation of the gate insulating film by CVD is mainly described. The gate insulating film is formed by CVD by supplying a source gas (for example, HTB: Hf (OC ₂ H ₅ ) ₄ and SiH ₄ ) onto the aforementioned silicon substrate heated in the range of 200 ° C. to 1000 ° C. Film formation (for example, HfSiO) is performed by reacting the formed reactive species (for example, Hf radical, Si radical, and O radical) on the film surface. The reactive species may be generated by plasma. Generally, the physical film thickness of the gate insulating film is 1 nm to 10 nm (FIG. 15).

(8): Polysilicon film formation for gate electrode On the High-k gate insulating film (including the base gate oxide film) formed in the above (7), polysilicon (including amorphous silicon) is CVD as the gate electrode of the MOS transistor. The film is formed by the method. Gate insulation is achieved by heating a silicon substrate on which a gate insulating film is formed within a range of 500 ° C. to 650 ° C. and introducing a gas containing silicon (such as silane or disilane) onto the substrate under a pressure of 10 to 100 Pa. A polysilicon film for an electrode having a thickness of 50 nm to 500 nm is formed on the film. As the gate electrode, silicon germanium or metal (W, Ru, TiN, Ta, Mo, etc.) may be used instead of polysilicon (FIG. 16).

  Thereafter, gate patterning and selective etching are performed to form a MOS capacitor (FIG. 17), and ion implantation (implantation) is performed to form a source and a drain (FIG. 18). Thereafter, the dopant (phosphorus (P), arsenic (As), boron (B), etc. implanted into the channel, source, and drain) is activated by annealing. Subsequently, a MOS transistor according to this embodiment is obtained through a wiring process that combines film formation of an interlayer insulating film, patterning, selective etching, and metal film formation, which are subsequent processes (FIG. 19). Finally, a logic device is completed by performing a wiring process on the transistor in various patterns and making a circuit.

In this embodiment, Hf silicate (HfSiO film) is formed as the insulating film, but it is also possible to form an insulating film having a composition other than that. As the gate insulating film, SiO ₂ and SiON having a low dielectric constant, which are conventionally used, and Al ₂ O ₃ , ZrO ₂ , and HfO ₂ having a high dielectric constant called SiN or Hi-k material having a relatively high dielectric constant are used. , Ta2O5, and silicates such as ZrSiO and HfSiO, and one or more selected from the group consisting of aluminates such as ZrAlO.

  In this embodiment, the purpose is to form a base gate oxynitride film, but it is also possible to use the base gate oxynitride film as it is as a gate insulating film without forming a high-k material. This is possible by controlling the thickness.

  In addition, an oxide film that is not subjected to nitriding treatment can be used as a base, or the oxide film itself can be used as a gate insulating film.

  Furthermore, if necessary, the pre-oxidation treatment and post-hydrogen treatment can be omitted, and the treatment order can be changed.

  An example of the processing order according to the purpose is shown below.

  1: Formation of gate oxide film Pre-oxidation treatment → Oxidation treatment → Poly film formation

  2: Formation of gate oxynitride film-1 oxidation pretreatment-> oxidation treatment-> nitridation treatment-> post-hydrogen treatment-> Poly film formation

  3: Formation of gate oxynitride film-2 oxidation pretreatment → nitridation treatment → oxidation treatment → post-hydrogen treatment → Poly film formation

  4: Formation of Hi-k underlayer oxide film Pre-oxidation treatment → Oxidation treatment → Thinning by post-hydrogen treatment → Hi-k film formation → Poly film formation

  5: Formation of Hi-k base nitride film Pre-nitridation treatment (similar to pre-oxidation treatment) → nitriding treatment → post-hydrogen treatment → Hi-k film formation → Poly film formation

  What has been described above is an example of an aspect of the present invention, and various other processing methods are possible with the same apparatus configuration.

  As described above, when the present invention is used, it becomes possible to perform a plurality of processes continuously in a reaction chamber having the same principle without exposing the silicon substrate to the atmosphere, for example, one reaction chamber. The footprint can be reduced by performing all the steps. Even when processing each process in a separate reaction chamber, the reaction chambers with the same operating principle are arranged, so the gas piping and operation panel can be made the same, realizing excellent maintenance and operability. it can. Furthermore, since the same apparatus is used, there is a low possibility of contamination between apparatuses, and even in a cluster configuration having a plurality of reaction chambers, the processing order can be changed variously. When this method is used, a gate insulating film having various characteristics can be manufactured.

It is a schematic cross section which shows an example of the MOS structure which can be formed by this invention. It is a partial schematic cross section which shows an example of the semiconductor device which can be manufactured with the formation method of the insulating film of this invention. It is a typical vertical sectional view which shows an example of the slot plane antenna (SPA) plasma processing unit which can be used for the formation method of the insulating film of this invention. It is a typical top view which shows an example of SPA which can be used for the manufacturing apparatus of the electronic device material of this invention.

It is a typical vertical sectional view which shows an example of the heating reactor unit which can be used for the formation method of the insulating film of this invention. It is a flowchart which shows an example of each process in the formation method of this invention. It is a flowchart which shows an example of each process in the formation method of this invention. It is a graph which shows the leak characteristic of the oxide film when not performing the plasma treatment before oxidation, when performing the plasma treatment before oxidation. The horizontal axis represents the electrical film thickness, and the vertical axis represents the leakage current value of the gate oxide film at the gate voltage Vfb-0.4V. FIG. 9 shows the flat band characteristics of a similar film. The horizontal axis represents the electrical film thickness, and the vertical axis represents the flat band voltage.

FIG. 10a shows the change over time in the electrical thickness of the gate oxynitride film using a plurality of steps (multi-process) according to the present invention (change in electrical thickness for each step). The horizontal axis represents the processing time, and the vertical axis represents the electrical film thickness. FIG. 10b shows the change over time of the flat band voltage of the film similar to FIG. 9 (change of the flat band voltage in each step). The horizontal axis is the processing time, and the vertical axis is the flat band voltage. The SIMS analysis result of the oxygen concentration in a film | membrane in the film | membrane similar to FIG. 9 is shown. The horizontal axis indicates the etching time in the analysis, and the vertical axis indicates the oxygen intensity. It is a schematic cross section showing an example of a silicon substrate surface on which a gate oxide film and a gate insulating film are formed. It is a schematic cross section which shows an example of the plasma processing on a substrate surface. FIG. 5 is a schematic cross-sectional view showing an example of forming a SiO ₂ film on a substrate using plasma, nitriding treatment, and hydrogen plasma treatment.

It is a schematic cross section showing an example of film formation of a Hi-k material. It is a schematic cross section which shows an example of formation of the gate electrode on a Hi-k material film. It is a schematic cross section which shows an example of formation of a MOS capacitor. It is a schematic cross section showing an example of source and drain formation by ion implantation (implantation). It is a schematic cross section which shows an example of the MOS transistor structure obtained by this invention.

Claims (13)

A method of forming an insulating film on a substrate for an electronic device;
A first step of cleaning the substrate with a plasma of a gas containing a rare gas;
A second step of oxidizing the substrate with a plasma of a gas containing a rare gas and oxygen to form an oxide film;
A third step of nitriding the oxide film with a plasma of a gas containing a rare gas and nitrogen;
A fourth step of performing a hydrogen plasma treatment on the nitrided oxide film with a plasma containing hydrogen;
Forming a high-k film on the processed substrate of the fourth step; and
A method characterized in that the first to fourth steps are performed under the same operating principle. A method of forming an insulating film on a substrate for an electronic device;
A first step of cleaning the substrate with a plasma of a gas containing a rare gas;
A second step of oxidizing the substrate with a plasma of a gas containing a rare gas and oxygen to form an oxide film;
A third step of performing hydrogen plasma treatment of the oxide film with plasma of a gas containing hydrogen;
Forming a High-k film on the processed substrate of the third step; and
The method according to claim 1, wherein the first to third steps are performed under the same operating principle. A method of forming an insulating film on a substrate for an electronic device;
A first step of cleaning the substrate with a plasma of a gas containing a rare gas;
A second step of nitriding the substrate with a plasma of a gas containing a rare gas and nitrogen to form a nitride film;
A third step of performing a hydrogen plasma treatment on the nitride film with a plasma of a gas containing hydrogen;
Forming a High-k film on the processed substrate of the third step; and
The method according to claim 1, wherein the first to third steps are performed under the same operating principle. The first step, the noble gas flow rate 500～3000Sccm, hydrogen gas flow rate is carried out under conditions of 0～100Sccm,
The method according to claim 2, wherein the second step is performed under the conditions of the rare gas flow rate of 500 to 3000 sccm, the oxygen gas flow rate of 10 to 500 sccm, the pressure of 3 to 500 Pa, and the temperature of 25 to 500 ° C. The first step, the noble gas flow rate 500～3000Sccm, hydrogen gas flow rate is carried out under conditions of 0～100Sccm,
The method according to claim 3, wherein the second step is performed under the conditions of the rare gas flow rate of 500 to 3000 sccm, the nitrogen gas flow rate of 3 to 300 sccm, the pressure of 3 to 500 Pa, and the temperature of 25 to 500 ° C. The method according to any one of claims 1 to 5 plasma of the first step containing hydrogen gas. The method according to any one of claims 1 to 6 Chapter third step under the same operating principle, to be performed in the same processing chamber via the vacuum. The method according to claim 1, wherein the first to third steps under the same operating principle are performed in a separate processing chamber via a vacuum. The method according to any one of claims 1 to 8 , wherein the first step is performed at a pressure of 7 to l33 Pa. The method according to any one of claims 1 to 9, wherein the plasma is generated through a planar antenna having a plurality of slots. The High-k _{is, Al 2 O 3, ZrO 2} , HfO 2, Ta 2 O 5, ZrSiO, method according to any one of claims 1 to 10 comprising at least one selected from the group consisting of HfSiO and ZrAlO . The method according to any one of claims 1 to 11 before the plasma cleaning, the substrate is wet-cleaned. The insulating film A method according to any one of claims 1 to 12 which is a gate insulating film.

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