KR100358952B1 - Chemical vapor deopositon apparatus and the method thereof - Google Patents

Abstract

A chemical vapor deposition apparatus and a method thereof are disclosed. A chemical vapor deposition apparatus includes: a reaction chamber in which a chemical vapor deposition process is performed on an object to be vaporized; First and second gas injection pipes for injecting first and second reaction gases into the reaction chamber, respectively; An exhaust port for exhausting gas in the reaction chamber; A gas inlet connected to the second gas inlet tube; A plasma is generated to generate a high-density plasma in order to generate a high-density plasma containing active particles by ionizing the second reaction gas by forming an induction magnetic field in the gas introduction part through which the second reaction gas flows, part; And a power supply unit for supplying power to the plasma generation unit.

The present invention provides a method of using a gas instead of a liquid raw material to induce a complete chemical reaction in a digital chemical vapor deposition apparatus, thereby reducing the amount of impurities contained in the liquid raw material, It is possible to simplify the device by not requiring other additional devices necessary for supplying the material, thereby reducing the production cost of the equipment.

Description

[0001] The present invention relates to a chemical vapor deposition apparatus and a method thereof,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemical vapor deposition apparatus and a method thereof, and more particularly, to a chemical vapor deposition apparatus that can simplify the structure and effectively suppress the incorporation of impurities into a thin film grown on a substrate.

In the digital chemical vapor deposition apparatus, which is widely used as a thin film deposition apparatus, which is an indispensable material for the semiconductor industry or the display industry, it is possible to simplify the apparatus by using a gas having excellent reactivity at a low pressure and a low temperature, And to provide a method for preventing mixing.

The thin film manufacturing process has a very wide range of applications such as microelectronics, optoelectronics, protective film coating, decorative coating and optical coating as well as semiconductor device manufacturing. These wide range of thin film materials are commercialized as insulation of semiconductor devices, gate oxide films, protective films, metal wiring for electrical signal transmission, etc., and have various sensors and electrical, optical and mechanical characteristics as their own, It is possible. Recently, as DRAM (Dynamic Random Access Memory) in the semiconductor field has become highly integrated, it is natural to use a thin film having a very fine line width and thickness in order to make a device having a higher integration degree in a smaller area.

Generally, thin film manufacturing methods include spin-on coating using polymer and sol-gel, physical vapor deposition (PVD) using sputtering or evaporation, chemical vapor deposition using chemical reaction A variety of methods such as a CVD method using an ion beam and a direct vapor deposition method using a liquid vapor have been used.

The most widely used methods in the semiconductor field are spin-on coating, physical vapor deposition and chemical vapor deposition. In particular, the technique of depositing a thin film by the chemical vapor deposition method is a technique that can increase the degree of integration and increase the demand thereof and overcome the disadvantages of the existing physical vapor deposition method. However, the technology for controlling the chemical reaction is very complicated and requires fine control .

Chemical vapor deposition (CVD) is the most popular technique, which involves injecting various gases into a gas, and then using gases such as heat, light, and plasma to induce reactions of the gases and deposit them on the substrate. In chemical vapor deposition, the rate of chemical reaction is controlled by the heat, light, plasma, etc., which supply the reaction energy, or through the amount and ratio of gas. However, these chemical reactions are generally very fast, and it is very difficult to control the deposition of atoms to achieve the thermodynamic stability of the atoms. Thin films deposited by chemical vapor deposition have disadvantages in that their physical, electrical, and chemical properties are lower than those due to physical vapor deposition, but they are an advantageous method for ensuring thin film uniformity in fine irregularities. In particular, the digital chemical vapor deposition (CVD) method has recently been known as a very popular technique because it provides a method of obtaining a thin film having excellent coating step at a low temperature.

The basic principle of digital chemical vapor deposition is that each reactant is alternately injected into the reaction chamber to grow a thin film by repeated adsorption, surface reaction, and chemical reaction of desorption

The digital thin film deposition reaction for growing the compound XY from the reactants AX and BY can be represented by the formula (1).

AX (g) + BY (g) -> Y (s) + AB (g)

This reaction can be explained by two processes of the following reaction equations (2) and (3). Equation (2) represents the surface reaction between the XY layer and the reactant AX, and Equation (3) represents the surface reaction between the AX layer and the reactant BY.

AX (g) + (XY) n (s) - > AX (XY)

(G) + AX (XY) - n (s) -> (XY) n + 1 (s) + AB

First, when AX is injected into the reactor, it is adsorbed on the surface of the substrate. At this time, surplus AX that is not adsorbed on the substrate is completely removed by purge gas, and an AX layer of an atomic layer (monolayer) adsorbed on the substrate surface is formed. When BY, which is another reactant, is injected into the reaction furnace, a surface reaction occurs with the AX layer previously adsorbed on the substrate. The excess gaseous BY and the gaseous reactant AB are completely removed by the removal gas, XY < / RTI >

Such a digital chemical vapor deposition reaction can be easily understood by a cluster model as shown in FIG. 1 (a), when the AX reactant is brought into contact with the substrate 10, as shown in FIG. 1 (b), the AX reactant causes a surface reaction with the substrate 10, The unreacted residual materials are completely removed by the purge gas, and the AX monolayer 11 is formed on the substrate 10 as shown in FIG. 1 (c). 1 (d), the BY reaction material is injected into contact with the monolayer 11 and the surface reaction is performed on the substrate 10 as shown in FIG. 1 (e) Surface reaction with the AX monolayer (11). 1 (f), the remaining BY reaction material that has not reacted with the by-product after the surface reaction has been generated is removed by the removing gas and is grown on the substrate 10 An XY thin film layer 12 is formed. Through the repetition of the above process, several layers of the XY thin film layer are grown on the substrate 10.

FIG. 2 shows the pulse time of the reactive material and the removing gas for causing the digital thin film deposition reaction. The A and B pulses supplied with the reactant and the elimination pulses injected with the purge gas are sequentially repeated. Unlike the chemical vapor deposition method in which the growth of the injected reactants is carried out by vapor phase reaction, the digital thin film deposition growth technique is capable of growing a single atom layer per cycle by using a self-controlled reaction mechanism by a saturated surface reaction .

3 is a schematic diagram of a conventional chemical vapor deposition apparatus.

Referring to FIG. 3, an RF coil (Radio Frequency Coil) 2 for generating plasma is provided around a reaction chamber 1 provided with a vacuum exhaust device 4 on one side, and a reaction coil , B, and other gases are provided in the raw material supply device 3. In the reaction chamber 1, a substrate 11 and a support 12 for supporting the substrate 11 are provided.

In such a chemical vapor deposition apparatus, the raw material used for the chemical vapor deposition is a liquid material, and the raw material feeder 3 supplies the liquid raw material to the grate binder 1 made into a gaseous state . Such an apparatus for converting a liquid raw material into a gas is a very expensive apparatus, and since impurities as well as substances necessary for a chemical reaction are present in the liquid raw material, the impurities may exist as impurities in a thin film to be grown .

The present invention provides a method of using a gas instead of a liquid raw material to induce a complete chemical reaction in a digital chemical vapor deposition apparatus, thereby reducing the amount of impurities contained in the liquid raw material, It is an object of the present invention to provide a chemical vapor deposition apparatus and a method thereof that can simplify a device by eliminating the need for other additional devices necessary for supplying a material, thereby reducing the production cost of equipment.

1 is a cluster model for explaining the digital chemical vapor deposition reaction.

FIG. 2 shows the pulse time of the reactive material and the removal gas for causing the digital thin film deposition reaction.

3 is a schematic diagram of a conventional chemical vapor deposition apparatus.

4 is a plan view showing a schematic configuration of an embodiment according to the chemical vapor deposition apparatus of the present invention to which the chemical vapor deposition method according to the present invention is applied.

5 is a side view showing a schematic configuration of an embodiment according to the chemical vapor deposition apparatus of the present invention to which the chemical vapor deposition method according to the present invention is applied.

In order to achieve the above object, according to the present invention,

A reaction chamber in which a chemical vapor deposition process is performed on the object to be vaporized;

First and second gas injection pipes for injecting first and second reaction gases into the reaction chamber, respectively;

An exhaust port for exhausting gas in the reaction chamber;

A gas inlet connected to the second gas inlet tube;

A plasma is generated to generate a high-density plasma in order to generate a high-density plasma containing active particles by ionizing the second reaction gas by forming an induction magnetic field in the gas introduction part through which the second reaction gas flows, part;

And a power supply unit for supplying power to the plasma generating unit.

In the chemical vapor deposition apparatus of the present invention, the first reaction gas injected into the reaction chamber through the first gas injection tube is in an un-ionized pure gas state, and the second reaction gas is O ₂ , H ₂ , N ₂ , an OH molecule, and a NH molecule.

In order to achieve the above object, according to the present invention,

Introducing a first reaction gas into a reaction chamber provided with an evaporation object to adsorb the first reaction gas on a surface of the evaporation object;

Converting the second reaction gas into plasma outside the reaction chamber;

Introducing the plasmaized second reaction gas into the reaction chamber and reacting with the first reaction gas adsorbed on the deposition target;

And exhausting the byproduct by the reaction of the first reaction gas and the second reaction gas.

In the above chemical vapor deposition apparatus and method of the present invention, the periphery of the path through which the plasmaized second reaction gas flows is electrically grounded, ions existing in the plasma are bypassed, and only the active particles in the plasma The reaction chamber is maintained at a pressure in the range of 8 mTorr to 10 Torr and the deposition object is maintained at a temperature within the range of room temperature to 500 ° C.

The deposition technique of the thin film processing apparatus of the present invention as described above is a technique of generating a remote plasma outside the chamber without generating plasma directly from the second reaction gas on the surface of the substrate in the reaction chamber, And the radicals generated in the plasma are chemically reacted with the first reaction gas adsorbed on the surface of the substrate to be deposited.

4 and 5 are a schematic plan view and a side view of a chemical vapor deposition apparatus to which a chemical vapor deposition method using a high density remote plasma according to the present invention is applied.

Referring to FIGS. 4 and 5, upper and lower heater assemblies 102a and 102b are positioned within reaction chamber 100 sealed by wall 101. As shown in FIG. On the inner surface of the lower heater assembly 102b, a substrate 200, which is an object to be deposited, is positioned.

An exhaust port 400 for evacuating the reaction chamber 100 in a vacuum state is provided at a lower side of the wall body 101. The first and second reaction gas supply devices 201 and 202 are provided at the other side of the wall 101 to introduce first and second reaction gases into the space between the upper and lower heater assemblies 102a and 102b. Second gas injection pipes 103 and 104 are provided.

Here, the first and second gas injection pipes 103 and 104 extend between the upper and lower heater assemblies 102a and 102b, and in some cases, only the wall 101 may be connected. Preferably, as shown in FIGS. 3 and 4, the second gas injection tube 103, 104 preferably extends between the upper and lower heater assemblies 102a, 102b, For example, the second gas injection tube 104 is preferably electrically grounded.

A plasma generating chamber 203 is provided on the outer side of the second gas injection tube 104, and an induction coil 204 for generating plasma is provided around the second gas injection tube 104. The induction coil 204 is an element of the plasma generating apparatus and is connected to the frequency measuring unit 204b via the impedance matching unit 204a and the frequency measuring unit 204b is connected to the power supplying apparatus 204c have.

The power supply unit 204c rectifies an alternating current of, for example, 220 volts and 60 Hz, and then generates alternating currents of 1 MHz to 13.56 MHz and amplifies and outputs the alternating currents. The frequency measuring unit 204b includes a power supply unit 204c, and the impedance matching unit 204a matches the impedances of the flow coils. The output from the power supply 204c is measured only once and is used to control the gain of the high frequency amplifier provided therein.

The induction coil 204 to which the high frequency power is supplied is supplied with the second reaction gas introduced into the plasma generation chamber 204 through the second reaction injection tube 104 by the induction magnetic field of a strong energy state, A high-density plasma having a radial is generated. In this high-density plasma, the activated particles, ions and electrons coexist and are introduced into the reaction chamber where the substrate is mounted. The ions and electrons pass through the wall of the introduction tube or pass through the induction tube Only excited species, that is, activated radicals, which are electronegative gases that do not react with each other, are chemically reacted with the first reactant gas which is adsorbed on the substrate in the reaction chamber 100, As shown in FIG.

According to the present invention, the second reaction gas injected into the plasma generation chamber may contain at least one selected from the group consisting of O ₂ , O ₃ , N ₂ O, N ₂ , H ₂ , OH molecules, .

According to the present invention, the plasma generating chamber 203 of the second reaction gas provided in chemical vapor deposition is preferably provided nearest to the reaction chamber 100, preferably within 1 m from the substrate, It is particularly preferable to be provided on the extension line of the second gas injection pipe 104.

According to the present invention, in order to stably supply the second reaction gas to the substrate, when the second reaction gas is supplied to the plasma generating part at a constant flow rate and is exhausted at a constant rate, the exhaust gas is stopped when the second reaction gas is supplied to the substrate, It is preferable to use a by-pass method of introducing gas.

Hereinafter, embodiments of the chemical vapor deposition method according to the present invention will be described in detail.

The chemical vapor deposition method of the present invention includes the steps of: introducing a first reaction gas into a reaction chamber provided with an evaporation object to adsorb the first reaction gas on the surface of the evaporation object; Converting the second reaction gas into plasma outside the reaction chamber; Introducing the plasmaized second reaction gas into the reaction chamber and reacting with the first reaction gas adsorbed on the deposition target; And exhausting the by-product resulting from the reaction of the first reaction gas and the second reaction gas.

In the following embodiments, the first reaction gas supplied first in an inactive state and the second reaction gas supplied in an activated state are discussed according to the target thin film material.

≪ Example 1 >

In the case where the thin film to be formed on the substrate is silicon dioxide (SiO ₂ ), tetraethoxysilane in which the silicon raw material contains oxygen atoms is supplied as a first reaction gas to the substrate and adsorbed, H ₂ plasma to reduce the first reaction gas to obtain a SiO ₂ thin film. Alternatively, the SiO ₂ thin film can be obtained by introducing a silicon raw material such as dichrolosilane as a first reaction gas into a reaction chamber and adsorbing it on a substrate, and bringing a plasma of a reducing material such as H ₂ into contact with the substrate have. Of course, other raw materials (silane, tetramethylesilane) can also be deposited by reduction of hydrogen atoms. In this reaction, silicon is adsorbed to the substrate as a single atomic layer, and oxygen is supplied to the adsorbed substrate to obtain a SiO ₂ thin film. At this time, hydrogen or oxygen itself forms a very stable chemical bond, and reaction with other gases does not occur easily. Thus, the second reaction gas is activated through a high-density remote plasma so that the reaction is likely to occur.

≪ Example 2 >

The material of the target thin film in the case of a tantalum nitride _{(TaN), Ta (OCH 3} ) 5, Ta (OC 2 H 5) 5, Ta (OC 3 H 7) 5, Ta [OCH (CH 3) 2] 5 _{, Ta (OC 4 H 9)} 5, Ta [OCH 2 CH (CH 3) 2] 5, Ta [OCH (CH 3) C 2 H 5] 5, Ta [OC (CH 3) 3] 5 , such as a tantalum raw material A material is supplied as a first reaction gas, and NH ₃ or H ₂ is used as a second reaction gas, and a high-density remote plasma is generated therefrom to be brought into contact with the first reaction gas.

≪ Example 3 >

Al (CH ₃ ) ₃ is used as a raw material of the first reaction gas and H ₂ is used as a second reaction gas to be plasma-ized in order to obtain Al or an Al ₂ O ₃ thin film by the chemical vapor deposition method. In this case, an Al thin film can be obtained by reducing H ₂ to Al (CH ₃ ) ₃ . As the second reaction gas for reduction, H ₂ O, N ₂ O, O ₂ , O _3, or H ₂ O ₂ activated by plasma can be applied, and thereby an Al ₂ O ₃ thin film having excellent electro- Can be obtained.

<Example 4>

In the case of forming a titanium nitride (TiN) thin film, a titanium raw material such as TiCl4, TDEAT (Tetrakis [diethylamino] titanium) or TDMAT (Tetrakis [dimethylamino] titanium) is used as the first reaction gas, NH ₃ or H ₂ is applied as a reaction gas.

&Lt; Example 5 >

In the case of forming an aluminum thin film doped with copper and silicon, triisobutylaluminium, copper (II) acetylacetonate [Cu (acac) 2]), teramethyl H ₂ is used as the first reactant gas and raw material such as teramethylsilane as the activated reducing gas (second reaction gas).

&Lt; Example 6 >

In the case of an alloy of titanium / silicon / nitrogen to deposit a silicon section jacheung, and activating the reactive gas by a high-density remote plasma to make them easy to occur the reaction of N ₂ after depositing a titanium section jacheung occur well reaction three-phase Substance material can also be deposited.

It can be applied to digital chemical vapor deposition of all materials not described in the above examples and can be explained by similar reaction mechanisms.

In the above-described digital chemical vapor deposition method of the present invention, the vacuum pressure in the reaction chamber during deposition is maintained at 10 Torr or less, preferably 8 mTorr to 10 Torr, 500 &lt; [deg.] &Gt; C enables more effective deposition.

The present invention provides a method of using a gas instead of a liquid raw material to induce a complete chemical reaction in a digital chemical vapor deposition apparatus, thereby reducing the amount of impurities contained in the liquid raw material, It is possible to simplify the device by not requiring other additional devices necessary for supplying the material, thereby reducing the production cost of the equipment.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation. Accordingly, the true scope of the present invention should be determined within the scope of the appended claims.

Claims (18)

A reaction chamber in which a chemical vapor deposition process is performed on the object to be vaporized; First and second gas injection pipes for injecting first and second reaction gases into the reaction chamber, respectively; An exhaust port for exhausting gas in the reaction chamber; A gas inlet connected to the second gas inlet tube; A plasma is generated to generate a high-density plasma in order to generate a high-density plasma containing active particles by ionizing the second reaction gas by forming an induction magnetic field in the gas introduction part through which the second reaction gas flows, part; And a power supply unit for supplying power to the plasma generating unit. The chemical vapor deposition apparatus according to claim 1, wherein the first reaction gas injected into the reaction chamber through the first gas injection tube is in an inactive gas state. The method according to claim 1 or 2, wherein the second reaction gas contains at least any one selected from the group consisting of N ₂ O, O ₂ , O ₃ , H ₂ , N ₂ , OH molecules and NH molecules Wherein the chemical vapor deposition apparatus is a chemical vapor deposition apparatus. The method according to claim 3, wherein the second reaction gas contains at least one selected from the group consisting of N ₂ O, O ₂ , O ₃ , H ₂ , N ₂ , OH molecules, Vapor deposition apparatus. 4. The chemical vapor deposition apparatus according to claim 3, wherein ions around the plasma are bypassed by electrically grounding the periphery of the path through which the plasmaized second reaction gas flows. 3. The method according to claim 1 or 2, Wherein the plasma is generated by electrically grounding the periphery of a path through which the plasmaized second reaction gas flows, so that ions present in the plasma are bypassed. 3. The method according to claim 1 or 2, Wherein the reaction chamber is maintained at a pressure in the range of 8 mTorr to 10 Torr. The method of claim 3, Wherein the reaction chamber is maintained at a pressure in the range of 8 mTorr to 10 Torr. The method according to claim 6, Wherein the reaction chamber is maintained at a pressure in the range of 8 mTorr to 10 Torr. 3. The method according to claim 1 or 2, Wherein the deposition object is configured to maintain a temperature within a range of room temperature to 500 ° C. The method of claim 3, Wherein the deposition object is maintained at a temperature within the range of room temperature to 500 ° C. The method according to claim 6, Wherein the deposition object is maintained at a temperature within the range of room temperature to 500 ° C. 8. The method of claim 7, Wherein the deposition object is maintained at a temperature within the range of room temperature to 500 ° C. Introducing a first reaction gas into a reaction chamber provided with an evaporation object to adsorb the first reaction gas on a surface of the evaporation object; Converting the second reaction gas into plasma outside the reaction chamber; Introducing the plasmaized second reaction gas into the reaction chamber and reacting with the first reaction gas adsorbed on the deposition target; And exhausting the by-product resulting from the reaction of the first reaction gas and the second reaction gas. 15. The chemical vapor deposition method of claim 14, further comprising: electrically grounding a periphery of a path through which the plasmaized first reaction gas flows to bypass ions present in the plasma. 16. The method according to claim 14 or 15, Wherein the pressure of the reaction chamber is maintained within the range of 8 mTorr to 10 Torr. 16. The method according to claim 14 or 15, Wherein the temperature of the deposition object is maintained within a range of room temperature to 500 ° C. 17. The method of claim 16, Wherein the temperature of the deposition object is maintained within a range of room temperature to 500 ° C.