KR100845887B1 - Apparatus and method for plasma processing and semiconductor substrate manufactured thereby - Google Patents

Abstract

Plasma processing methods and apparatuses and semiconductor substrates produced thereby are disclosed. The plasma processing apparatus of the present invention includes a multi-core plasma generator for generating induced electromotive force for generating plasma in a plasma reactor. Plasma is excited by the induced electromotive force of the multi-core plasma generation and plasma processing is performed on the substrate to be processed, wherein the substrate support supports the substrate to be processed inside the plasma reactor, Maintained at zero potential. The plasma processing method and apparatus of the present invention can form a high density plasma by a multi-core plasma generator and maintain the high density plasma uniformly without causing any field on the substrate. Therefore, it is possible to effectively suppress the damage of the substrate most concerned in the plasma treatment process, thereby ensuring the reliability of the device.

Plasma, oxidation, nitridation, oxynitride

Description

Plasma processing method and apparatus and semiconductor substrate manufactured by the same {APPARATUS AND METHOD FOR PLASMA PROCESSING AND SEMICONDUCTOR SUBSTRATE MANUFACTURED THEREBY}

In order to more fully understand the drawings used in the detailed description of the invention, a brief description of each drawing is provided.

1 is a schematic diagram of a configuration of a plasma processing apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic perspective view of the plasma reactor of FIG. 1.

3 is a cross-sectional view of the plasma generator of FIG. 2.

4 to 6 are diagrams showing examples of multiple cores.

7A to 7D illustrate a plasma treatment process in which a nitriding process is sequentially performed on a silicon substrate after an oxidation process.

FIG. 8 is a diagram illustrating XPS spectra after nitriding a SiO ₂ thin film.

9A to 9D illustrate a plasma treatment process in which a nitriding process is sequentially performed on a silicon substrate after an oxynitride process.

* Description of the symbols for the main parts of the drawings *

100: plasma reactor 110: substrate support

120: vacuum pump 130: gas supply source

140: power supply 142: impedance matcher

200: multi-core plasma generator 300: substrate to be processed

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus and a plasma processing method which can be suitably used when performing various plasma processing on a target object for manufacturing an electronic device or the like. Specifically, the present invention relates to a plasma processing method and apparatus for forming a thin film on the surface of a target object using plasma, and a semiconductor substrate manufactured using the same.

As the degree of integration of semiconductor devices increases, the size of the devices decreases rapidly, and as a result, the thickness of the thin films rapidly decreases, causing various problems. In the case of the gate dielectric oxide, as the thickness thereof is reduced, the leakage current increases as well as the device reliability. In addition, the doping profile of the channel region due to diffusion of dopants in the polysilicon gate or the element that destroys the oxygen binding in the gate oxide. By doing so, a problem of deteriorating device reliability has been caused. In order to solve this problem, efforts have been made to suppress diffusion of impurities by nitriding oxide films to increase dielectric constant of gate insulating thin films and forming nitride films of high density.

In addition, when a high dielectric thin film is used as an insulator, an alloy thin film such as HfSiO may cause phase separation between HfO ₂ and SiO ₂ during subsequent heat treatment. This impairs the stability of the threshold voltage, causing serious problems with the stability of the device. In order to solve this problem, introduction of a process of nitriding a high dielectric thin film in a subsequent heat treatment process is under consideration.

However, the problem of the nitriding process is to reduce the nitriding between the gate dielectric thin film and the silicon substrate while maintaining high density of nitriding inside the gate dielectric thin film. However, the formation of Si ₃ N ₄ at the interface imposes a high stress on the silicon substrate, causing inherent interstitial Si, which creates an oxide trap at the interface. Such an oxide trap has a problem of causing serious damage to the reliability and speed of the device.

On the other hand, the oxidation or nitriding method using plasma can maintain the interface quality required by the conventional thermal oxidation method at a low temperature, and is recognized as a very effective method for a very thin thickness process. Therefore, a method of forming a gate oxide film using plasma has been proposed, and in the atomic layer deposition method, it has been proposed to be used as a reactant of a high-k dielectric thin film using high reactivity of plasma.

As an oxidation or method using a conventional plasma, a process using an RF plasma or a DC plasma or the like has been proposed. While maintaining high plasma density, the uniformity of the large area should be maintained, and low plasma energy should bring high density of nitride while minimizing interface damage. However, the conventional methods of oxidation, nitridation and oxynitride using plasma have the advantage of maintaining high density plasma density, but inevitably have a disadvantage that a certain amount of electric field is applied to the substrate to maintain high density plasma.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems, and to oxidize, nitrate, and oxynitride a substrate without subjecting any electric field to the substrate while maintaining high density of plasma density and large area uniformity. There is provided a plasma processing method and apparatus and a semiconductor substrate manufactured using the same.

One aspect of the present invention for achieving the above technical problem relates to a plasma processing method. According to an aspect of the present invention, there is provided a plasma processing method comprising: preparing a plasma reactor for plasma processing a substrate and a multi-core plasma generator for generating induced electromotive force for generating plasma in the plasma reactor; Preparing a substrate to be processed on an internal substrate support of the plasma reactor, and setting the interior of the plasma reactor to the processing air pressure; Introducing a gas for plasma processing the substrate to be processed; Plasma is excited by induced electromotive force of the multi-core plasma generator; Plasma processing of the substrate to be processed by the excited plasma is performed, wherein the substrate to be placed on the substrate support in the plasma processing step maintains a zero potential.

In one embodiment, the gas introduced into the plasma reactor for the plasma treatment is selected from at least two or more kinds of gases including an inert gas, an oxygen atom and a gas containing a nitrogen atom.

In one embodiment, the plasma treatment is any one of an oxidation treatment, a nitriding treatment, and an oxynitride treatment.

Another aspect of the invention relates to a plasma processing apparatus. According to another aspect of the present invention, a plasma processing apparatus includes: a plasma reactor for performing one or more plasma processing of an oxidation treatment, a nitriding treatment, and an oxynitride treatment on a substrate to be processed; A multi-core plasma generator for generating induced electromotive force for generating a plasma inside the plasma reactor; A gas supply unit for introducing at least two or more kinds of gases, including an inert gas, a gas containing nitrogen atoms, and a gas containing oxygen atoms, to plasma-treat the substrate to be processed; And a substrate support for supporting the substrate under the plasma reactor, the substrate support maintaining a substrate potential at zero potential in the plasma treatment of the substrate.

In one embodiment, by adjusting the flow rate ratio of the gas containing the oxygen atom and the gas containing the nitrogen atom to adjust the peak of the nitrogen concentration in the oxynitride film formed on the substrate to be processed.

Another aspect of the invention relates to a semiconductor substrate manufactured by the plasma processing method and apparatus. A semiconductor substrate according to another aspect of the present invention is manufactured by the plasma processing method and apparatus according to one side and the other side of the present invention.

DETAILED DESCRIPTION In order to fully understand the present invention, the operational advantages of the present invention, and the objects achieved by the embodiments of the present invention, reference should be made to the accompanying drawings which illustrate preferred embodiments of the present invention and the contents described in the accompanying drawings. The embodiments of the present invention may be modified in various forms, and the scope of the present invention should not be construed as being limited by the embodiments described below. This embodiment is provided to more completely explain the present invention to those skilled in the art. Accordingly, the shape of the elements in the drawings and the like are exaggerated to emphasize a clearer description. In understanding the drawings, it should be noted that like parts are intended to be represented by the same reference numerals as much as possible. And detailed description of known functions and configurations that are determined to unnecessarily obscure the subject matter of the present invention is omitted.

(Example)

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings to describe a plasma processing method and apparatus of the present invention and a semiconductor substrate manufactured using the same.

1 is a schematic diagram of a configuration of a plasma processing apparatus according to an embodiment of the present invention. Referring to FIG. 1, the plasma processing apparatus used in the present invention includes a plasma reactor 100 having a multi-core plasma generator 200 and a substrate support 110 supporting the substrate 300. The substrate 300 to be processed may be, for example, a silicon wafer substrate for manufacturing a semiconductor device or a glass substrate for manufacturing a liquid crystal display device or a plasma display device.

The plasma reactor 100 receives a gas required for the plasma processing process from the gas source 130. The plasma reactor 100 is connected to the vacuum pump 120 to maintain a process air pressure necessary for the plasma processing process, and after the process is completed, the residual gas therein is exhausted by the vacuum pump 120.

The multi-core plasma generator 200 is located on top of the plasma reactor 100 opposite the substrate support 110. The multi-core plasma generator 200 receives the radio frequency from the power supply 140 through the impedance matcher 142 to generate induced electromotive force inside the plasma reactor 100 to generate plasma. The power supply 140 may be configured using a radio frequency generator capable of controlling the output power without a separate impedance matcher.

FIG. 2 is a schematic perspective view of the plasma reactor of FIG. 1, and FIG. 3 is a sectional view of the plasma generator of FIG. 2.

2 and 3, the plasma reactor 100 includes a vacuum chamber 110 and a multi-core plasma generator 200 thereon. The multi-core plasma generator 200 is composed of a plurality of discharge induction bridges 210 installed across the top of the vacuum chamber 110. The plurality of discharge induction bridges 210 have a tubular structure. Multiple discharge induction bridges 320 are equipped with multiple loop cores 230. The plurality of discharge induction bridges 210 may be made of a metal material or an electrically insulating material. In the case of a metal material, it is preferable to include an insulating region 220 to prevent the eddy current from being generated. In addition, although not illustrated in detail, the multi-core plasma generator 200 may include a cooling channel to prevent the multi-core plasma generator 200 from overheating.

4 to 6 are diagrams showing examples of multiple cores. 4 to 6, the multi-loop core 230 may be configured using a plurality of magnetic cores that form independent loops as shown in FIG. 4. Alternatively, as shown in FIG. 5, a magnetic core integrated with a plurality of loops adjacent to each other may be used. Alternatively, as shown in FIG. 6, the lattice structure may be configured using an integrated magnetic core so as to have a regularly repeated structure. At least one primary winding 240 is wound around each loop of the multiple loop core 230. One or more primary windings 240 may be provided for one loop of the magnetic core.

The plurality of primary windings 240 of the multi-loop core 230 may be connected to the power supply 140 through an impedance matcher 142 in any one of a series, parallel, and parallel or parallel mixing scheme. In addition, a current balancing circuit may be added to balance a current amount of radio frequency supplied to the plurality of primary windings 240. When the current balancing circuit is added, the plasma uniformity can be further increased.

Referring back to FIGS. 2 and 3, the gas supply unit 120 is configured at the top of the multi-core plasma generator 200. The gas supply unit 120 includes a gas inlet 121 for introducing a gas supplied from the gas supply source 130, and the gas introduced between the plurality of discharge induction bridges 210 as indicated by arrows in FIG. 3. It is injected into the vacuum chamber 110 through. The gas supply unit 120 may include one or more gas distribution plates (not shown) for gas distribution. In addition, the gas supply unit 120 may have two or more separate gas supply paths so that different gases may be supplied separately. For example, different gases may be alternately injected between the plurality of discharge induction bridges 210.

Meanwhile, referring back to FIG. 1, the inductively coupled plasma reactor of the present invention may be modified to have a structure having a zero potential without supplying a bias power. In the plasma reactor according to the present invention, plasma processing on the substrate 300 may be performed without supplying a bias power in a structure that generates high-density plasma.

Next, a plasma processing process will be described for the substrate 300 to be processed using the plasma processing apparatus of the present invention as described above. The plasma treatment process described in this embodiment includes a process of forming an oxynitride film by performing a nitriding process after an oxidation process on a silicon substrate and a process of forming an oxynitride film by performing a nitridation process after an oxynitride process Let's explain.

7A to 7D illustrate a plasma treatment process in which a nitriding process is sequentially performed on a silicon substrate after an oxidation process.

First, the substrate 300 to be processed, which is a silicon wafer, is loaded on the substrate support 110, and then the gas inside the vacuum chamber 110 is exhausted through the vacuum pump 120 to process the substrate inside the vacuum chamber 110. Is set to a processing pressure suitable for. Inert gas and oxygen gas (gas containing oxygen atoms) are then introduced into the vacuum chamber. Meanwhile, the radio frequency is supplied from the power supply 140 to the multi-core plasma generator 200, and the plasma is excited by the induced electromotive force 250 transmitted from the multi-core plasma generator 200, as shown in FIG. 7A. As described above, oxygen radicals are generated from the inert gas and the oxygen gas, and an oxide film 300 is formed on the silicon wafer 300 as shown in FIG. 7B.

At this time, since the substrate support 110 is not applied to any field, a high density plasma having a low electron temperature of 1.0 (eV) or less is formed. Therefore, unnecessary charges do not accumulate in the silicon wafer 300 and a high quality oxide film without plasma damage can be formed. In addition, since the plasma has a high density and low electron temperature, the silicon wafer 300 can be disposed close to the plasma, thereby completing the oxidation process in a very short time and at a low power.

Next, a process of forming a high density nitride film by performing a nitriding process on the silicon wafer substrate 300 on which the oxide film 310 is formed will be described. After the above-described oxidation process is completed, the substrate 110 to be processed is loaded on the substrate support 110 to exhaust the residual gas inside the vacuum chamber 110, and then process the interior of the vacuum chamber 110 suitable for substrate processing. Set to pressure. Inert gas and nitrogen gas (gas containing nitrogen atoms) are then introduced into the vacuum chamber. Meanwhile, the radio frequency is supplied from the power supply 140 to the multi-core plasma generator 200, and the plasma is excited by the induced electromotive force 250 transmitted from the multi-core plasma generator 200, as shown in FIG. 7C. As described above, nitrogen radicals are generated from the inert gas and the nitrogen gas. As illustrated in FIG. 7D, the oxide film 310 on the silicon wafer 300 is nitrided to form an oxynitride film 320a.

As also described above, since the substrate support 110 is not applied to any field, a high density plasma having a low electron temperature of 1.0 (eV) or less is formed. Therefore, an unnecessary charge does not accumulate in the silicon wafer 300 and a high quality oxynitride film without plasma damage can be formed. In addition, since the plasma has a high density and low electron temperature, the silicon wafer 300 can be placed close to the plasma, thereby completing the nitriding process in a very short time and at a low power.

FIG. 8 is a diagram illustrating XPS spectra after nitriding a SiO ₂ thin film. Referring to FIG. 8, after the nitriding process is performed on the oxide film of the silicon wafer 300 by the plasma processing apparatus and method of the present invention, the N 1s XPS peak is displayed to enable high density nitrogen addition even at a very short time and low power. It can be seen.

9A to 9D illustrate a plasma treatment process in which a nitriding process is sequentially performed on a silicon substrate after an oxynitride process.

First, the substrate 300 to be processed, which is a silicon wafer, is loaded on the substrate support 110, and then the gas inside the vacuum chamber 110 is exhausted through the vacuum pump 120 to process the substrate inside the vacuum chamber 110. Is set to a processing pressure suitable for. Inert gas and oxygen gas (gas containing oxygen atoms) and nitrogen gas (gas containing nitrogen atoms) are then introduced into the vacuum chamber. Meanwhile, the radio frequency is supplied from the power supply 140 to the multi-core plasma generator 200, and the plasma is excited by the induced electromotive force 250 transmitted from the multi-core plasma generator 200, as shown in FIG. 9A. As described above, oxygen radicals and nitrogen radicals are generated from inert gas, oxygen, and nitrogen gas, and an oxynitride film 320 is formed on the silicon wafer 300 as illustrated in FIG. 9B.

At this time, since the substrate support 110 is not applied to any field, a high density plasma having a low electron temperature of 1.0 (eV) or less is formed. Therefore, an unnecessary charge does not accumulate in the silicon wafer 300 and a high quality oxynitride film without plasma damage can be formed. In addition, since the plasma has a high density and low electron temperature, the silicon wafer 300 can be placed close to the plasma, thereby completing the oxynitride process in a very short time and low power.

Next, a process of forming a high density nitride film by performing a nitriding process on the silicon wafer substrate 300 on which the oxynitride film 320 is formed will be described. After the above-described oxynitride process-processed substrate 110 is loaded on the substrate support 110, the remaining gas inside the vacuum chamber 110 is exhausted, and the inside of the vacuum chamber 110 is suitable for substrate processing. Set to the processing pressure. Inert gas and nitrogen gas are then introduced into the vacuum chamber. Meanwhile, the radio frequency is supplied from the power supply 140 to the multi-core plasma generator 200, and the plasma is excited by the induced electromotive force 250 transmitted from the multi-core plasma generator 200, as shown in FIG. 9C. As described above, nitrogen radicals are generated from the inert gas and the nitrogen gas. As illustrated in FIG. 9D, the oxynitride film 310 on the silicon wafer 300 is nitrided to form the oxynitride film 320a. Here, the peak of the nitrogen concentration in the oxynitride film may be adjusted by adjusting the flow rate ratio of oxygen and nitrogen gas.

Also in this process, as described above, since the substrate support 110 is not applied to any field, a high density plasma having a low electron temperature of 1.0 (eV) or less is formed. Therefore, an unnecessary charge does not accumulate in the silicon wafer 300 and a high quality oxynitride film without plasma damage can be formed. In addition, since the plasma has a high density and low electron temperature, the silicon wafer 300 can be placed close to the plasma, thereby completing the nitriding process in a very short time and at a low power.

Over the oxide layer or the increase in the inner membrane by the nitriding process for the oxynitride nitride such may increase suppressing the diffusion of the impurity effectively the film density, formation of Si ₃ N ₄ in the inner film is of the conventional SiO ₂ The dielectric constant can be increased from 3.9 to ~ 7. Thus, for example, even in the same EROM (EPROM tunnel oxide), the physical thickness can be increased to reduce leakage current. This is a process required for mobile devices requiring low standby power or low power consumption, and may be widely used in subsequent processes after the gate oxide layer is formed in the future.

The plasma processing apparatus and method of the present invention as described above may be used in an apparatus and a process such as CVD for forming an oxide film or a nitride film, the process of forming the oxide film or nitride film prior to the subsequent heat treatment of the gate oxide film formed on the semiconductor substrate, and It can also be used as a device. It may also be used as a process and apparatus for supplying reactants such as ALD or ALCVD.

Embodiments of the plasma processing method and apparatus of the present invention and the semiconductor substrates manufactured using the same are only illustrative, and various modifications and equivalents may be made by those skilled in the art to which the present invention pertains. It will be appreciated that other embodiments are possible. BACKGROUND OF THE INVENTION The plasma processing apparatus of the present invention is generally widely used for plasma processing, including the manufacture of materials for electronic devices such as semiconductors, semiconductor devices, liquid crystal devices, and the like.

Therefore, it is to be understood that the present invention is not limited to the specific forms mentioned in the above description. Therefore, the true technical protection scope of the present invention should be defined by the technical spirit of the appended claims, and the present invention is intended to cover all modifications, equivalents, and substitutes within the spirit and scope of the present invention as defined by the appended claims. It should be understood to include.

According to the plasma processing method and apparatus of the present invention as described above and a semiconductor substrate manufactured using the same, a high density plasma is formed by a multi-core plasma generator and uniformity of the high density plasma is generated without causing any field on the substrate. Can be kept stable. Therefore, it is possible to effectively suppress the damage of the substrate most concerned in the plasma treatment process, thereby ensuring the reliability of the device.

Claims (10)

In the plasma processing method of performing a plasma treatment on a substrate to be processed: Preparing a plasma reactor for plasma processing a substrate to be processed and a multi-core plasma generator for generating induced electromotive force for generating plasma in the plasma reactor; Preparing a substrate to be processed on an internal substrate support of the plasma reactor, and setting the interior of the plasma reactor to a processing air pressure; Introducing a gas for plasma processing the substrate to be processed; Plasma is excited by induced electromotive force of the multi-core plasma generator; Plasma processing is performed on the substrate to be processed by the excited plasma, In the step of introducing the gas by adjusting the flow rate ratio of the gas containing oxygen atoms and the gas containing nitrogen atoms to adjust the peak of the nitrogen concentration in the oxynitride film formed on the substrate to be processed And the substrate to be placed on the substrate support in the plasma processing step maintains a zero potential. The method of claim 1, The gas introduced into the plasma reactor for the plasma treatment is selected from at least two or more kinds of gases including an inert gas, an oxygen atom and a gas containing a nitrogen atom. The method of claim 1, The plasma treatment method is any one of an oxidation treatment, a nitriding treatment, and an oxynitride treatment. The semiconductor substrate manufactured by the plasma processing method of any one of Claims 1-3. In the plasma processing apparatus for performing a plasma processing on a substrate to be processed, A plasma reactor for performing a plasma treatment of at least one of an oxidation treatment, a nitriding treatment, and an oxynitride treatment on a substrate to be treated; A multi-core plasma generator for generating induced electromotive force for generating a plasma inside the plasma reactor; A gas supply unit for introducing at least two or more kinds of gases, including an inert gas, a gas containing nitrogen atoms, and a gas containing oxygen atoms, to plasma-treat the substrate to be processed; A substrate support for supporting a substrate within the plasma reactor, the substrate support maintaining a substrate potential at zero potential in a plasma treatment of the substrate, And a peak of a concentration of nitrogen in the oxynitride film formed on the substrate to be processed by adjusting a flow rate ratio of a gas containing an oxygen atom and a gas containing a nitrogen atom. delete A semiconductor substrate manufactured by the plasma processing apparatus of claim 5. In the plasma processing apparatus for performing a plasma processing on a substrate to be processed, A plasma reactor for performing a plasma treatment of at least one of an oxidation treatment, a nitriding treatment, and an oxynitride treatment on a substrate to be treated; A multi-core plasma generator for generating a plasma inside the vacuum chamber including a plurality of discharge induction bridges installed across the upper inside of the vacuum chamber of the plasma reactor and a plurality of loop cores installed in the plurality of discharge induction bridges; And a gas supply unit for introducing at least two or more kinds of gases, including an inert gas, a gas containing nitrogen atoms, and a gas containing oxygen atoms, for plasma-processing the substrate to be processed into the vacuum chamber. The method of claim 8, And controlling the peak ratio of the nitrogen concentration in the oxynitride film formed on the substrate to be processed by adjusting the flow rate ratio of the gas containing the oxygen atom and the gas containing the nitrogen atom. The semiconductor substrate manufactured by the plasma processing apparatus as described in any one of Claims 8-9.

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