KR20030079610A - Automatic Valve Control System in Plasma Chemical Vapor Deposition System and Chemical Vapor Deposition System for Deposition of Nano-Scale Mulilayer Film - Google Patents

Abstract

The present invention relates to a plasma chemical vapor deposition equipment and an automatic valve control system for chemical vapor deposition equipment for manufacturing nanoscale multilayer films having nano-scale ultra high hardness and multifunction.

The present invention provides a system for manufacturing a multilayer thin film using plasma chemical vapor deposition and chemical vapor deposition equipment, comprising: a chamber capable of forming a multilayer thin film with at least two components by plasma chemical vapor deposition and chemical vapor deposition; At least two source supplies for supplying a reactant comprising components constituting any one layer of the multilayer thin film; At least two paths connected in the middle to each of the source supply parts, each end connected to the chamber, and the other end connected to a bypass pipe for adjusting the flow rate; A vacuum pump connected to the bypass pipe; Automatic valves of the plasma chemical vapor deposition equipment and chemical vapor deposition equipment for the nano-scale multilayer film production, characterized in that it comprises at least four valves installed on both sides of each of the paths around the source supply connection portion opening and closing Provide an adjustment system.

Description

Automatic Valve Control System in Plasma Chemical Vapor Deposition System and Chemical Vapor Deposition System for Deposition of Nano-Scale Mulilayer Film}

The present invention relates to a plasma chemical vapor deposition apparatus and an automatic valve control system for chemical vapor deposition equipment for manufacturing nanoscale multilayer films, and more particularly, to nano-scale using plasma chemical vapor deposition and chemical vapor deposition. The present invention relates to a plasma chemical vapor deposition equipment and an automatic valve control system for chemical vapor deposition equipment for manufacturing nanoscale multilayer films having ultra high hardness and multifunction.

Due to the development of vacuum technology, research on the manufacture and commercialization of various vacuum coatings is being actively conducted. The superlattice (or artificial lattice) thin film to be dealt with in the present invention is also one of them.

Superlattice thin film is a basic research model for exploring interfacial properties between dissimilar materials and is a term applied to a multilayer film in which the thickness of each layer is reduced to nanoscale (nm).

By adjusting the heterogeneous material in the direction of the thickness of the film to a scale nearly close to the lattice spacing of the crystals present in nature, it is regarded as an artificial one-dimensional lattice.

A model diagram of an ideal superlattice is shown in FIG. 1. The materials A and B each have inherent properties in the multilayer thin film in which the micron (μm) level layer is laminated, but the expected overall multilayer film functions as a composite material taking only the average value of the two materials or the good points of A and B.

In contrast, in the case of a superlattice thin film laminated at a nanoscale, materials A and B do not necessarily exhibit inherent properties, but exhibit new properties as a whole. In other words, it has new material properties that are completely different from the original materials A and B.

The reason why the superlattice thin film exhibits such a new characteristic is not yet clearly identified, but it is mainly reported to be due to lattice distortion effect, interfacial effect, layer structure effect, and artificial cycle effect between heterogeneous materials. .

When the superlattice thin film is applied to a hard coating, two different metal and ceramic (carbide, nitride, etc.) layers are repeatedly deposited, and the dislocation movement and interlayer interface (each layer) are repeated. The movement of dislocations moving across the interface is suppressed to obtain a high hardness of 50 GPa or more.

At this time, in order to effectively suppress dislocation movement, the thickness of each layer should be able to be adjusted to about several nanometers (˜nm).

In order to obtain the characteristics of the superlattice thin film mentioned above, in addition to adjusting the thickness of each layer to about nm, concentration gradients due to diffusion of heterogeneous materials at the interface should not occur. Using a sputtering device designed to enable the rotation of or by using an evaporation (Evaporation) using two independent evaporation sources.

In the case of the sputtering method, two different targets are installed facing each other, and sputtering rotates the substrate at a constant speed, and when the substrate comes to the front of each target, the material is mainly deposited. It is known that the thickness of each layer can be controlled from the rotational speed of the substrate and the intensity control of the bias applied to the target.

The evaporation method is performed by periodically controlling the evaporation of heterogeneous materials through the opening and closing of shutters installed in front of two evaporation sources.

With the above sputtering and evaporation methods, superlattice thin films can be manufactured by a relatively simple method and the thickness of each layer can be easily adjusted. However, due to the limitations of physical vapor deposition, complex shapes Has the disadvantage that deposition of thin films on the substrate is almost impossible.

Chemical Vapor Deposition (CVD) and Plasma Chemical Vapor Deposition (PECVD) are methods for depositing and supplying a reaction material in the form of a gas, and focusing on this, manufacturing a multilayer thin film by controlling a gas flow meter (MFC) A study was attempted.

For example, in order to obtain a multilayer thin film of TiN and TiCN, the supply of CH ₄ gas is controlled by controlling on / off time of a mass flow meter (MFC). However, in this case, since it takes about 1 minute to stabilize the gas flow rate through the flow control device, it is impossible to control the thickness of each layer to several tens of nm or less, and moreover, to supply liquid and solid reactants in gaseous form. When using a bubbler or evaporator, much more time is required to stabilize the flow rate, making the thickness control of each layer through the flow regulator much more difficult.

Accordingly, the present invention has been made in view of the problems of the prior art, the object of which is to control the supply of the source quickly and accurately in order to successfully produce a superlattice thin film using plasma chemical vapor deposition and chemical vapor deposition, Plasma chemistry for the production of nanoscale multilayer films that can eliminate the constraints of the substrate type of physical vapor deposition such as sputtering and evaporation To provide an automatic valve control system of the vapor deposition equipment and chemical vapor deposition equipment.

1 is an exemplary diagram for explaining an ideal superlattice thin film structure.

Figure 2 is a block diagram illustrating an automatic valve control system of the plasma chemical vapor deposition equipment for producing nanoscale multilayer film according to the present invention.

3 is a transmission electron micrograph of a TiN / AlN superlattice thin film prepared according to the present invention.

Figure 4 is a graph showing the hardness change of the TiN / AlN superlattice thin film prepared according to the present invention.

Explanation of symbols on the main parts of the drawings

10 chamber 11 exhaust pipe

12: first pump 13: table

14: heating section 15: power supply section

16: specimen 17: plasma generator

20 valve system 21 first connection pipe

22: first route 23: second route

24: second connecting pipe 25: first source supply pipe

26: 2nd source supply pipe 27-30: 1st-4 valve

40: matching part 45: RF generating part

In order to achieve the above object, the present invention is a system for manufacturing a multilayer thin film using the plasma chemical vapor deposition method and chemical vapor deposition method, the multilayer thin film with at least two components by plasma chemical vapor deposition method and chemical vapor deposition method A chamber capable of being formed; At least two source supplies for supplying a reactant comprising components constituting any one layer of the multilayer thin film; At least two paths connected in the middle to each of the source supply parts, each end connected to the chamber, and the other end connected to a bypass pipe for adjusting the flow rate; A vacuum pump connected to the bypass pipe; Automatic valves of the plasma chemical vapor deposition equipment and chemical vapor deposition equipment for the nanoscale multilayer film production, characterized in that it comprises at least four valves installed on both sides of each of the paths around the source supply connection portion opening and closing Provide an adjustment system.

The valves are configured as a solenoid valve capable of automatic opening and closing, the present invention further comprises a control unit for controlling the opening and closing of the valves each at a predetermined time interval, the control unit controls the valves, the at least two The multi-layered thin film is formed by supplying materials required for the thin film composition supplied through the two paths and the source supply unit to the chamber in a predetermined order.

The apparatus may further include a third source supply unit for smoothly performing the process. When using a source having components that react with each other and solidify while being introduced into the chamber, the third source source may be used. The supply unit may be directly supplied to the chamber. In the case of plasma chemical vapor deposition, a source for continuously and stably forming plasma during the process may be supplied through the third source supply unit. The third source supply unit further comprises a solenoid valve capable of opening and closing control to control the source supply.

As described above, by smoothly and quickly controlling the supply of the source, the present invention can easily and quickly and precisely manufacture a nano-scale multilayer thin film using plasma chemical vapor deposition and chemical vapor deposition.

(Example)

Hereinafter, with reference to the accompanying drawings showing a preferred embodiment of the present invention described above in more detail.

2 is a block diagram illustrating an automatic valve control system of a plasma chemical vapor deposition apparatus for manufacturing a nanoscale multilayer film according to the present invention, and FIG. 3 is a TiN / AlN superlattice thin film manufactured according to the present invention. 4 is a graph showing the hardness change of the TiN / AlN superlattice thin film prepared according to the present invention.

Automatic valve control system used in the present invention is shown in Figure 2. The reactor of the conventional plasma chemical vapor deposition apparatus, that is, the chamber (chamber) 10 was used as it is, and the reactant gases supplied, that is, the first source 31 and the second source 32, were supplied through the valve system 20. It is designed to be supplied to 10).

In the valve system 20, the first to fourth valves 27 to 30, which consist of pneumatic valves, are used. The first to fourth valves 27 are solenoids which are electrically on / off for automatic control. It is connected to the valve.

The valve system 20 has a first connecting pipe 21 connected to the chamber 10 and a second pump 33 connected to the second pump 33 to bypass the reaction gas. A first path 22 and a second path 23, the first path 22 and a first pipe 22 connected in parallel to the connection pipe 24, the first connection pipe 21 and the second connection pipe 24, respectively. A first source supply pipe 25 and a second source supply pipe 26 connected to the middle of the second path 23 to receive and deliver a source from the first source 31 and the second source 32, respectively; It consists of the 1st-4th valves 27-30 which are respectively provided in the said 1st path | route 22 and the 2nd path | route 23 centering on the 1st source supply pipe 25 and the 2nd source supply pipe 26. As shown in FIG.

Here, the bypass tube, i.e., the second connecting tube 24, is essential for maintaining a constant gas flow rate during the manufacture of the multilayer thin film, the end of which is intended to prevent the back stream of the gas expected at the inlet of the pump. It is connected to a second pump 33 that operates independently of the first pump 12 used in the chamber 10 for prevention.

The chamber 10 is made of cylindrical 304 stainless steel having a diameter of 30 cm and a height of 24 cm, and a plasma generator 17 for generating plasma is installed on the chamber 10, and the plasma generator 17 is provided. The planar capacitive type electrode is built in and operates by receiving power supplied from the RF generator 45 through the matching unit 40.

The specimen 13 is installed on the table 13 installed at the lower portion of the chamber 10, and the specimen 16 is formed of a resistance wire and generates a heating part by generating power by the power supplied by the power supply unit 15. Heated to the process temperature set by step 14).

The chamber 10 and the table 14 and the like except for the plasma generator 17 are electrically grounded.

The pressure in the chamber 10 is then measured by a thermocouple gauge.

In the superlattice thin film manufactured by the system according to the present invention, TiN and AlN were repeatedly deposited with a thickness of each nm unit. At this time, TiCl ₄ , H ₂ , and NH ₃ were used as the reaction gases for the deposition of TiN, and AlCl ₃ and NH ₃ were used as the reaction gases for the deposition of AlN.

Each thermodynamic reaction process is shown in Schemes 1 and 2, and specific process conditions are shown in Table 1.

2TiCl ₄ (g) + 2NH ₃ (g) + H ₂ (g) = 2TiN (S) + 8HCl (g)

AlCl ₃ (g) + NH ₃ (g) = AlN (s) + 3HCl (g)

Since TiCl ₄ and AlCl ₃ exist in the liquid and solid phases at room temperature, respectively, the TiCl ₄ and AlCl ₃ are introduced into the chamber 10 by bubbling with a carrier gas in an evaporator, and as a carrier gas. Ar and H ₂ were used, respectively. In addition, Ar was further supplied to assist in activating the plasma when AlN was deposited.

The flow rate of each gas was kept constant by using a gas flow meter (mass flow meter, MFC), the flow rate of the reaction gas flowing into the chamber 10 by the bubble reaction was adjusted by the following principle.

_Between the flow rate of the carrier gas (Q _car ) flowing into the vaporizer and the flow rate of the reactor gas (Q _rxn ) introduced into the reactor by the bubble reaction, the pressure of the carrier gas (P _car ) and the vapor pressure of the reactor gas (P _rxn ) In general, relations such as Equations 1 and 2 are established.

At this time, P _T can be confirmed by using a pressure gauge attached to the vaporizer. If the pressure of the vaporizer is kept constant, the flow rate of the reaction gas flowing into the reactor is the flow rate of the carrier gas flowing into the vaporizer and the It can be said to be a function of vapor pressure. When the unit of pressure and temperature of TiCl ₄ and AlCl ₃ is mmHg and absolute temperature K, respectively, the vapor pressure P is expressed as in Equation 3 and Equation 4.

Thus, the vapor pressures of TiCl ₄ and AlCl ₃ are a function of temperature only, and thus the flow rate of the reactor gas can be adjusted by controlling the temperature of each vaporizer and the flow rate of the carrier gas.

Meanwhile, since NH ₃ reacts with TiCl ₄ or AlCl ₃ gas at low temperature to form a solid compound such as TiCl ₄ · nNH ₃ , AlCl ₃ · nNH ₃ , or NH ₄ Cl to block the inlet gas pipe, A plurality of small holes 18 formed in the electrode plate formed in the plasma generating unit 17 installed in the chamber 10 were distributed evenly, and for controlling the gas inflow, a third source such as NH ₃ was introduced. A third source supply pipe 35 is connected between the 34 and the chamber 10, and the third source supply pipe 35 is opened and closed by a fifth valve 36 formed of a solenoid valve.

The plasma generator 17 has a circular plate shape, and the reaction gases supplied to the chamber from the first source 31 and the second source 32, that is, TiCl ₄ and AlCl ₃ gases,

A circular gas injector (19) provided in the plasma generator 17 and the specimen 16 was uniformly introduced.

Summarizing the above, the sources 1 and 2 used in the present invention are summarized according to FIG. 2 as follows.

Source 1: TiCl ₄ , Ar, H ₂

Source 2: AlCl ₃ , Ar, H ₂

Process Conditions of TiN / AlN Superlattice Thin Films TiN AlN Reaction gas and flow rate TiCl ₄ : 1.4sccm AlCl ₃ : 1.9sccm H ₂ : 100sccm H _2: 100sccm Ar: 40sccm Ar: 40sccm NH _{3: 20} sccm Process temperature 530 ℃ RF power 50 W Total thickness of the deposited film 2-3㎛

The first pump 12 and the second pump 33 is composed of a mechanical rotary pump (mechanical rotary pump), the RF generator 45 is composed of a radio frequency generator (radio frequency generator) of frequency 13.56 MHz The matching unit 40 used a capacitor matching impedance box.

TiN / AlN multilayer thin film prepared in the present invention was prepared in the following sequence.

Step 1. The flow rate is stabilized while exhausting TiCl ₄ and AlCl ₃ and other reaction gases Ar and H ₂ supplied through the vaporizer through the second pump 33 connected to the second connecting pipe 24 for a predetermined time.

Step 2. When the flow rates of all reaction gases are stabilized, NH ₃ is introduced into the chamber 10 through the small holes of the upper electrode plate, which is the plasma generating unit 17, to form a plasma.

Step 3. Once the plasma is stabilized, the first valve 27 and the third valve 29 are closed for the deposition of TiN, so that all of the reactants for TiN deposition, that is, TiCl ₄ , H ₂ , and NH ₃ , are released from the chamber 10. Inflow). At this time, the fourth valve 30 is opened to allow the reaction material for AlN deposition, that is, AlCl ₃ and NH _3, to be exhausted by the second pump 33 so that there is no change in the flow rate.

Step 4. After the deposition of the TiN, the first valve 27 is closed and the third valve 29 is opened to wait for the reaction material such as TiCl ₄ remaining in the chamber 10 to be completely exhausted. In order to prevent the preliminary gradient of Ti concentration at the interface of TiN and AlN, which is expected when the reaction gas is introduced, it is necessary to obtain a clean interface. In the present invention, it took about 10 seconds.).

Step 5. Now open the second valve 28 and close the fourth valve 30 to allow the reactant gases for AlN deposition to flow into the chamber 10. At this time, similarly, the third valve 29 is opened so that the flow rate of TiCl ₄ or the like is kept constant.

Step 6. Repeat the process of Step 4 to remove residual gas such as AlCl ₃ remaining in the chamber 10.

Table 2 shows the on / off state of each valve for the above sequence.

On / off status of each valve according to the process sequence order Chamber condition Valve on / off status 1st valve 2nd valve 3rd valve 4th valve 5th valve Order 1 Stabilization of Flow Rate of Reaction Gas off off on on off Order 2 Plasma formation off off on on on Order 3 TiN deposition on off off on on Order 4 Interface off off on on on Order 5 AlN Deposition off on on off on Order 6 Interface off off on on on

By repeating the above steps 3 to 6 it was possible to effectively grow the TiN / AlN superlattice thin film. At this time, the thickness of each layer was controlled by varying the deposition time (steps 4 and 6) from the growth rate of the TiN and AlN single layer thin films obtained through preliminary experiments, and the thickness of 2 to 3 μm necessary for application to the hard film. Steps 3 to 6 were repeated about 300 to 500 times to grow the superlattice thin film.

The opening and closing control of each valve is controlled automatically by supplying an electrical signal to the solenoid valve connected to the first to fourth valves 27 to 30 through a computer program.

Looking at the transmission electron microscopy (see Fig. 3) of the TiN / AlN superlattice thin film prepared by the above process, the specimen observed by electron microscopy has a bilayer period of about 5nm Appeared across.

In FIG. 3, the brightly visible portion represents the TiN layer, and the darkly visible portion represents the AlN layer. In this case, the bilayer period means the sum of the thicknesses of TiN and AlN.

As shown in FIG. 3, it was confirmed that the thickness of the superlattice thin film manufactured by the present invention was effectively controlled within several nm.

In addition, when looking at the hardness change of the TiN / AlN multilayer thin film prepared according to the present invention, as shown in Figure 4, the multilayer thin film showed a maximum hardness of 5000 (HK _0.01 ) or more when the repetition period is about 5nm. Considering that the hardness of the TiN and AlN single layer thin films manufactured by the conventional plasma chemical vapor deposition method is _about 2500 (HK _0.01 ) and 1200 (HK _0.01 ), respectively, the TiN / AlN multilayer thin film prepared according to the present invention has the characteristics of a superlattice thin film. It is shown to indicate.

The present invention made as described above was able to successfully manufacture a nanoscale multilayer thin film exhibiting the properties of the superlattice thin film by plasma chemical vapor deposition without a change in the flow rate of the reaction gas. In addition, the present invention can overcome the disadvantages of physical vapor deposition (PVD), such as sputtering, and is a very innovative invention in that it provides a new method for manufacturing a superlattice thin film.

In the above, the present invention has been illustrated and described with reference to specific preferred embodiments, but the present invention is not limited to the above-described embodiments and the general knowledge in the technical field to which the present invention pertains without departing from the spirit of the present invention. Various changes and modifications will be made by those who possess.

Claims (7)

A system for producing a multilayer thin film using plasma chemical vapor deposition and chemical vapor deposition, A chamber capable of forming a multilayer thin film using at least two components by plasma chemical vapor deposition and chemical vapor deposition; At least two source supplies for supplying a reactant comprising components constituting any one layer of the multilayer thin film; At least two paths connected in the middle to each of the source supply parts, each end connected to the chamber, and the other end connected to a bypass pipe for adjusting the flow rate; A vacuum pump connected to the bypass pipe; Automatic valves of the plasma chemical vapor deposition equipment and chemical vapor deposition equipment for the nano-scale multilayer film production, characterized in that it comprises at least four valves installed on both sides of each of the paths around the source supply connection portion opening and closing Regulation system. The automatic valve control system of claim 1, wherein the at least four valves are configured as a solenoid valve capable of automatically opening and closing. 2. . The method of claim 1, further comprising another source supply for directly supplying the chamber having a component which reacts with each other while being introduced into the chamber from among the sources supplied through the at least two source supply. Automatic valve control system of plasma chemical vapor deposition equipment and chemical vapor deposition equipment for nanoscale multilayer film production. [4] The automatic valve control of the plasma chemical vapor deposition apparatus and the chemical vapor deposition apparatus according to claim 3, wherein the other source supply unit further comprises a solenoid valve capable of opening and closing control to control the source supply. system. 5. The plasma chemistry of claim 1, further comprising a control unit that controls the opening and closing of the valves at predetermined time intervals. 6. Automatic valve control system of vapor deposition equipment and chemical vapor deposition equipment. The method of claim 5, wherein the control unit controls the valves to supply a material necessary for the composition of the thin film supplied through the at least two paths and the source supply unit to the chamber in a predetermined order to form a multilayer thin film. Automatic valve control system of the plasma chemical vapor deposition equipment and chemical vapor deposition equipment for manufacturing nanoscale multilayer film. The plasma chemical vapor deposition apparatus of claim 1, further comprising a gas injector connected to one end of the path and installed in the chamber to uniformly inject the source. Automatic valve control system of chemical vapor deposition equipment.