WO2015020487A1

WO2015020487A1 - Apparatus and method for forming electronic material film

Info

Publication number: WO2015020487A1
Application number: PCT/KR2014/007398
Authority: WO
Inventors: 홍문표; 이준영; 장진녕
Original assignee: 고려대학교 산학협력단
Priority date: 2013-08-08
Filing date: 2014-08-08
Publication date: 2015-02-12

Abstract

The present invention relates to a method and an apparatus for forming an electronic material film using a sputtering process. The present invention is characterized by blocking an oxygen anion and a secondary electron generated in the sputtering process and controlling a value (P·D) obtained by multiplying the sputtering pressure (P) and the distance (D) between a sputtering target and an object to ensure a ratio (D/λ) of the distance (D) between a sputtering target and an object to the average free path (λ), the ratio being lower than 1 and satisfying a relationship between the initial energy (I_O) of an electronic material film forming particle and the energy (I) of when the electronic material film forming particle reaches an object, the relationship satisfying I=αI_O (0.4<α<1).

Description

Other material film forming apparatus and method

The present invention relates to an electronic material film forming apparatus and method, and more particularly to an oxide electronic material film forming apparatus and method that does not require heat treatment.

Transparent conducting oxides (TCOs) and oxide semiconductors (Oxide Semiconductors, OxSCs) are representative materials for electronic materials and are used in a wide variety of semiconductor devices, display devices, and solar devices.

In general, the deposition process using the sputtering technique is most commonly used for the deposition of TCO and OS thin films. The sputtering technique, which is the easiest to secure productivity and stability, and the characteristics of the thin films, is a conductive oxide depending on the material of the deposited TCO and OS thin films. An additional high temperature heat treatment is required before coating the substrate on the substrate and / or after forming the transparent conductive thin film layer.

In particular, the ITO thin film, which is known to have the highest light transmittance and electrical conductivity, is known to have more than 85% visible light transmittance and excellent resistivity of 4x10 ^-4 Ωcm, but after the ITO thin film is deposited on the substrate, An additional high temperature heat treatment process of 200 ° C. to 500 ° C. is necessary to improve the thin film properties.

However, since the high temperature heat treatment process causes very fatal damage to the organic light emitting device and the plastic substrate, it is very unsuitable for the manufacturing process of the flexible electronic device based on the plastic substrate. There is a great need for new process development for formation methods.

In addition, in addition to the plastic substrate-based flexible electronic device, the organic light emitting device and the organic solar cell using the plasma buffer layer and the layer having the same role do not require additional heat treatment. It can be called a process.

Particularly, in the case of the transparent electrode used in the flexible electronic device, durability of bending characteristics must be satisfied, so durability characteristics of bending of the transparent electrode used are very important, and thus high conductivity and high durability against bending In order to be satisfied, the development of TCO thin film formation process with nanocrystalline structure with low thin film stress should also be made.

In order to form a highly transparent electrode that satisfies the above characteristics, first, a thin film by very high energy of oxygen anion and secondary electrons generated during sputtering of most TCO thin films during sputtering of TCO thin films by sputtering technique in a room temperature region It must be possible to effectively suppress the physical damage of

To this end, the inventor of the present invention has developed and applied for a patent application of an electronic material film forming apparatus having a limiter for blocking oxygen anions between a sputtering means and an object on which an electronic material film is formed in a chamber in which a sputtering process is performed. 10-2012-0000317)

However, after repeated experiments under various conditions, even if some of the oxygen anions were blocked by these limiters, the electronic material film did not always form an excellent electronic material film that does not require an additional heat treatment process, and still requires an additional heat treatment process. It was confirmed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an apparatus and method for forming an electronic material film having excellent resistivity even without a heat treatment process.

It is another object of the present invention to provide plasma ions, sputtered particles and neutral particles with sufficient activation and crystallization energy to the electronic material film, while blocking high-energy oxygen anions, secondary electrons, etc. which cause damage to the electronic material film. It is an object of the present invention to provide an apparatus and a method capable of forming an electronic material film under certain conditions.

It is still another object of the present invention to provide an electronic material film forming apparatus and method capable of minimizing accumulation of particles when a limiter is provided between a sputtering means and a substrate holding means to block oxygen anions causing damage to the electronic material film. To provide.

It is still another object of the present invention to provide a method for forming an electronic material film having excellent properties even at room temperature to low temperature.

An electronic material film forming method according to an embodiment of the present invention is a method of forming an electronic material film on an object by using a sputtering process, in which oxygen anion and secondary electrons generated in an electronic material film target during a sputtering process are moved to an object. and to reach the block or deceleration that, in between the first kinetic energy (I _O) and said electronic material layer formed particles having as electronic material film-forming particles of energy (I) to reach the target object I = αI _O (0.4 The electronic material film is formed under the condition that the ratio (D / λ) of the average free path (λ) to the distance (D) between the sputtering target and the object satisfying the <α <1) relationship is secured. It is characterized by.

The ratio (D / λ) of the average free path to the distance between the spattering target and the object is adjusted by adjusting the value (P · D) of the sputtering pressure P multiplied by the distance (D) between the target and the object. It can be secured.

When the process gas is argon, it is preferable that the value (P · D) multiplied is adjusted to 0.01 Torr · mm or more and 0.42 Torr · mm or less.

An electronic material film forming apparatus according to an embodiment of the present invention is a chamber in which a sputtering process is performed, a sputtering means fixedly disposed on one surface of the chamber, and equipped with an electronic material film target, and one surface inside the chamber in which the sputtering means is disposed. A holding means disposed on an opposite surface to the object on which the electronic material film is formed, and disposed between the sputtering means and the holding means to block the influence of oxygen anions and secondary electrons generated in the sputtering process. And a limiter having a plurality of slits through which the material film forming particles can pass and magnets generating a magnetic field in a direction perpendicular to the moving direction of the electronic material film forming particles in each slit. It is movable in the direction crossing the slit, the sputtering target and the object The distance (D) between the sputtering process pressure (P) is determined as a condition that can limit the number of collisions with the process gas to less than one while the particles affecting the formation of the electronic material film reaches the object, Satisfying the relationship of I = αI _O (0.4 <α <1) between the initial kinetic energy (I _O ) of the electronic material film-forming particles and the energy (I) when the electronic material film-forming particles reach the object. The ratio D / λ of the average free path λ with respect to the distance D between the target and the object is controlled to be less than 1.

In general, it is preferable that the distance D between the target and the object has a value of 0.9 times or less of the average free path λ.

In addition, the distance between the limiter and the object is preferably smaller than the distance between the target and the limiter.

In addition, the limiter preferably has a curved structure in cross section between the plurality of slits and outside the slits at both ends.

When the process gas of the sputtering process is argon, the value P · D obtained by multiplying the distance D between the target and the object by the sputtering pressure P is preferably 0.01 Torr · mm or more and 0.42 Torr · mm or less.

The present invention blocks the high-energy oxygen anion and secondary electrons that cause damage to the electronic material film while maintaining the condition that plasma cations, sputtered particles and neutral particles can supply sufficient activation and crystallization energy to the electronic material film. It has the effect of forming an electronic material film having excellent characteristics even at room temperature to low temperature without high temperature heat treatment.

1 is a cross-sectional view illustrating an electronic material film forming apparatus according to an embodiment of the present invention.

FIG. 2 is a plan view of the limiter shown in FIG. 1. FIG.

3 and 4 are sectional views showing the cap provided in the limiter.

5 is an energy graph of sputtered particles and process gas particles incident on an object according to a pressure * distance (P · D) value when a direct current −300 V is applied to a sputter gun.

6 illustrates a general DC magnetron sputtering (DMS) technique according to pressure * distance (P · D) conditions when argon is used as a process gas, and the magnetic field shielded sputtering (MFSS) proposed by the present invention. A graph showing the electrical properties of ITO thin films formed by the technique.

7 shows TEM images and electron diffraction patterns of ITO thin films formed by DMS and MFSS techniques when argon is used as a process gas and pressure * distance (P · D) is 0.24, or α is 0.59. to be.

The get invention relates to an apparatus and method for forming an electronic material film using a sputtering process.

In particular, the present invention is to ensure that the high energy oxygen anion and secondary electrons generated in the electronic material film target during the sputtering process to reach the object in a state in which the blocking or energy is reduced so as not to damage the electronic material film formed on the object Plasma cations such as argon and helium ions, and kinetic energy of the electron material film-forming particles required to form the electronic material film, such as reflected neutral atoms formed by reflecting after collision on the target surface, are preserved without loss. It is characterized in that to maintain the appropriate level of energy required for forming a thin film of good quality.

1 is a cross-sectional view of an electronic material film forming apparatus according to an embodiment of the present invention.

Referring to FIG. 1, in an electronic material film forming apparatus according to an embodiment of the present invention, sputtering means 21 and sputtering, in which an electronic material film target 23 is mounted on one surface of a chamber 10 in which a sputtering process is performed. A magnetic field in a direction perpendicular to the moving direction of the ions and electrons generated in the sputtering process between the holding means 31 and the sputtering means and the holding means. The limiter 40 which produces | generates is arrange | positioned.

In the present invention, as shown in FIG. 1, the limiter 40 is disposed between the sputtering means and the holding means so that high energy oxygen anions and secondary electrons do not physically damage the electronic material film formed on the object.

As shown in FIG. 2, magnets of different magnetic poles are attached to both sides of the slit 45, which is a space in which ions and electrons generated in the sputtering process can move, thereby generating a magnetic field perpendicular to the direction of movement of ions and electrons. Generated and constrains electrons in the plasma to have negative electric potential, and the particles having high energy (oxygen anion and secondary electrons) that damage the electronic material film formed on the object 33 by the negative electric potential Block or slow down to reach the subject.

In addition, since the electronic materials are not uniformly deposited on the object 33 by the limiter, the holding means 31 on which the object 33 is mounted crosses the length direction of the slit as shown in FIG. And orthogonal to each other).

The configuration and function of each of these components is described in detail in the applicant's Republic of Korea Patent Application Publication No. 10-2012-0000317, it may distract the subject matter of the present invention of the detailed description thereof will not be described in detail in the present invention Let's do it.

However, when the limiter is configured as shown in FIG. 2, the electronic material film-forming particles are deposited on the upper limiter, and the stressed material film is peeled off and falls off at the edge portion to contaminate the electronic material film formed on the object and cause defects. .

Therefore, it is preferable that the cross section between the slit and the slit and both end slits outside has a curved structure which does not form an edge.

For example, the bar region between the slit and the slit and the outer portion of the slit located at both ends form a cap 50 having a circular or semicircular cross section as shown in Figs. Its shape can be configured such that the cross-section is in the form of a circle or semi-circle, by this structure it is possible to minimize the peeling of the thin film deposited on the upper limiter falling on the object.

As described above, the electronic material film may be formed without physical damage by restricting the high energy oxygen anion and the secondary electrons generated from the electronic material film target 23 using the limiter or limiting the energy to reach the object in a decelerated state. have.

However, even when the electronic material film is formed in such a limited state, particles affecting the formation of the electronic material film, such as sputtered particles, positive ions of the process gas, and neutral particles, which impinge and reflect on the surface of the sputter, are affected by the sputtering process gas. When the energy is lost due to the collision of, it is confirmed that even if a large amount of particles forming the electronic material film reaches the object, they simply accumulate and fail to form a high quality electronic material film, and thus heat treatment is required to form a high quality electronic material film.

Accordingly, in the present invention, as shown in FIG. 1, the sputtering pressure P and the distance D between the target and the object are appropriately adjusted so that the electronic material film forming materials have sufficient energy to form a high quality electronic material film without heat treatment. The ratio D / λ of the mean free path (λ) with respect to the distance D between the target and the target that may reach the object may be controlled to be less than 1.

In more detail, the probability that energy is conserved when the electronic material film-forming material collides with the sputtering process gas is as follows.

I = I ₀ e- ^{(D / λ)} . = ΑI ₀ ............................. (Equation 1)

Where I is the energy of the electronic material film-forming particles upon reaching the object, IO is the initial energy of the electronic material film-forming particles, D is the distance between the target and the object, λ is the mean free path, and α is the electron material film-forming particle. The energy decay rate by collision with the process gas until it is reached.

The present invention aims to ensure physical and electrical properties of the formed electronic material film even if the object is not subjected to high temperature treatment before and / or after the formation of the electronic material film. For this purpose, the range of α is preferably 0.4 <α <1. .

This range of α is based on the basic condition that the number of collisions with the process gas must be less than one time (energy attenuation rate α = e ^-1 = 0.37 in one collision) while the particles affecting the formation of the material film reach the object. It is the range derived based on the experimental results deposited by applying the invention.

In Equation 1, α has the following relationship with the distance D between the target and the object and the average free path λ.

-Ln (α) = D / λ ........................ (Equation 2)

Therefore, in order to satisfy the range of 0.5 <α <1, the distance D between the target and the object should have a value of 0.9 times or less of the average free path λ.

In addition, the α value has the following relationship with the sputtering pressure P and the distance D between the target and the object.

-Ln (α) = D / λ = D (σn _g ) ∝ DP ... (Equation 3)

Here, sigma is the collision cross-section of the electron material film-forming particles and the sputtering process gas particles, and n _g is the density of the process gas particles.

Since the average free path λ is the maximum distance that the electronic material film-forming particles can move without colliding with the process gas particles, the process gas that is the impingement cross section area σ and the number of process gas particles per unit volume, as shown in Equation 2 above. The product of the particle density (n _g ) is the inverse of the product, and the product of the impingement cross section (σ) and the density of the process gas particles (n _g ) is equal to the sputtering pressure (P), which is the pressure of the sputtering process particles between the electronic material film target and the object. Proportional.

In the electronic material film forming process, the distance D and the sputtering pressure P between the electronic material film target and the object are controllable values. However, there are limiting factors such as the minimum sputtering pressure to perform the sputtering process and the minimum distance to be maintained between the target and the object in order to have the limiter, and the average free path when the pressure P is high even though the distance D is minimized. The energy is not sufficiently conserved due to the long length, and even if the pressure P is minimized, the energy is not sufficiently conserved when the distance D is relatively long compared to the average free path.

Therefore, since only one value can be adjusted to satisfy 0.4 <α <1, the distance D between the target and the object and the sputtering pressure P are controlled together to form a high quality electronic material film without heat treatment. It should be possible to ensure a ratio (D / λ) of the average free path (λ) to a distance (D) of less than 1 to reach the object with sufficient energy.

In addition, even if a part of the oxygen anions are blocked or decelerated by the electron layer formed in the limiter 40, since the oxygen anions passing through the limiter 40 are accelerated again, the distance between the limiter 40 and the object 33 is increased. It is preferred to be smaller than the distance between the target 23 and the limiter 40.

In addition, the initial energy or the optimal attained energy of the particles has different values depending on the material, which is determined by the power or voltage applied to the sputtering gun but can only be changed linearly in conventional equipment. On the other hand, the energy decay due to the collision changes exponentially, and the α value for each collision number decreases sharply to 0.37 at one time, 0.14 at two times, and 0.05 at three times. Absolutely big. Therefore, it is preferable to control the distance D and the sputtering pressure P between the electronic material film target and the object so that the electronic material film forming materials have sufficient energy to form a high quality electronic material film.

FIG. 5 shows energy graphs of sputtered particles and process gas particles incident on an object when a direct current of −300 V is applied to the sputter gun.

Referring to FIG. 5, as the pressure * distance P · D increases, the energy of particles incident on the object decreases, and when the pressure * distance P · D is greater than 0.42, 0.48 and 0.72, some particles It can be seen that has a lower energy (Activation Energy) enough to form a high quality electronic material film.

At all pressure * distance (P · D) values, the energy of the oxygen anion has high energy which damages the electronic material film, but in the present invention, the oxygen anion having high energy is blocked using a limiter or the energy is damaged in the electronic material film. It is reduced to the extent that it does not cause the physical damage of the electronic water film.

Referring to FIG. 6, the resistivity, the carrier charge density, and the mobility value change according to the pressure * distance P · D value.

In more detail, the larger the pressure * distance (P · D) value, the lower the moving charge density and the charge mobility. In particular, the resistivity value of the ITO thin film used in the organic light emitting device, the flexible electronic device, and the organic solar cell is 10 ^{−. Although} it can be used as a wiring only in the range of ³ Ωcm, referring to FIG. 6, in all cases using the DMS technique, it can be seen that the specific resistance value is greater than 10 ⁻³ Ωcm. In the case of using the MFSS technique, the resistivity value is 10 ^-3 Ωcm or less when the pressure * distance (P · D) is below a certain size, but when the pressure * distance (P · D) is further increased, the resistivity is 10. ^It can be confirmed that it becomes ^-3 Ωcm or more.

In the case of argon plasma sputtering from which the results of FIG. 6 were obtained, the pressure * distance (P · D) values 0.24, 0.48, and 0.72 were converted into α values 0.59, 0.35, and 0.21 for the argon (Ar) particles, respectively. Therefore, when the α value satisfies 0.4 <α <1, it can be seen that a good quality ITO thin film is formed without heat treatment. When the process gas of the sputtering process is argon, the range is 0.01Torr · mm ≤ P · D ≤ 0.42 Torr. Mm. When α = 1, the P · D value is 0 Torr · mm, which means that the energy of the particles incident on the substrate is 100% conserved, which means that the object lies directly in front of the sputter or the pressure drops below 0.1 mTorr. Since the average free path is impossible if it is not several ten times larger than the distance from the sputter to the object, the minimum value of P · D is 0.01 Torr · mm when calculating the minimum distance and minimum pressure at which the limiter can be used.

FIG. 7 shows a TEM image and an electron diffraction pattern of an ITO thin film formed by the DMS technique and the MFSS technique when the pressure * distance (P · D) value is 0.24. In the MFSS technique, which is equipped with a limiter capable of charging oxygen ions with high energy, the nanocrystal structure is distinct in ITO thin film deposited at room temperature under 0.24 Torr · mm condition where the pressure * distance (P · D) value is 0.42 Torr · mm or less. You can check it.

Thin films deposited by the MFSS technique using a limiter under the same pressure * distance (PD) conditions formed nanocrystalline structures, but thin films deposited using the conventional DMS sputtering method were deposited as amorphous thin films. This determines whether the deposited thin film is damaged by the blocking of high energy oxygen anions, and preserves the energy of neutral particles or cations other than the deposited oxygen anions up to the substrate to be deposited. Show results that can be formed.

So far it has been described in detail with respect to the electronic material film forming apparatus and method according to the present invention with reference to the accompanying drawings.

According to the present invention, it is possible to form a high quality electronic material film without heat treatment in a state in which a high energy oxygen anion generated from forming an electronic material film using TCO or OxSC material is blocked from reaching an object or reaches a state where energy is lowered. It is the invention of the most suitable sputtering process environment possible. Therefore, although ITO (Indium Tin Oxide) has been described as an electronic material in the above description, the Indium Zinc Oxide (IZO), the Indium Zinc Tin Oxide (IZTO), and AZO (Aluminium) are used as electronic materials for forming an electronic material film according to the present invention. Both TCO and OS such as Zinc Oxide) may be used, and metal thin film deposition which does not generate oxygen anions is not included in the scope of the present invention.

In addition, the sputtering process gas is described based on Ar gas, which is a representative non-reactive gas, but may include all plasma forming gases such as Xe, Kr, N2, and He.

The scope of the present invention is not limited to the above-described embodiment, but may be implemented in various forms of embodiments within the scope of the appended claims. Without departing from the gist of the invention claimed in the claims, it is intended that any person skilled in the art to which the present invention pertains falls within the scope of the claims described in the present invention to various extents which can be modified.

Claims

A method of forming an electronic material film on an object using a sputtering process,

To prevent the oxygen anion generated from the electronic material film target during the sputtering process to block or slow down to reach the object,

A spar satisfies the relationship of I = αI O (0.4 <α <1) between the initial kinetic energy (IO) of the electron-forming film-forming particles and the energy (I) when the electron-forming film-forming particles reach the object An electronic material film forming method, wherein the electronic material film is formed under a condition that a ratio (D / λ) of the average free path (λ) to the distance (D) between the turing target and the object is secured.
The method of claim 1,

The average free path is secured by adjusting a value (P · D) obtained by multiplying a distance (D) between the target and the object by a sputtering pressure (P).
The method of claim 2,

The said process gas particle is argon, The said product (P * D) is 0.01 Torr * mm or more and 0.42 Torr * mm or less, The electronic material film formation method characterized by the above-mentioned.
A chamber in which a sputtering process is performed;

Sputtering means fixedly disposed on one surface of the chamber, the sputtering means mounting an electronic material film target;

Holding means disposed on a surface opposite to one surface of the chamber in which the sputtering means is disposed, and holding an object on which an electronic material film is formed; And

Disposed between the sputtering means and the holding means to block oxygen anions generated in the sputtering process, a plurality of slits through which electronic material film forming particles can pass, and inside of each slit of the electronic material film forming particles And a limiter having a magnet for generating a magnetic field in a direction perpendicular to the moving direction.

The holding means is movable in a direction crossing the slit,

The distance (D) and the sputtering pressure (P) between the target and the object are between the initial kinetic energy (IO) of the electronic material film forming particles and the energy (I) when the electronic material film forming particles reach the object. And an average free path λ satisfying a relationship of I = αI O (0.4 <α <1) is secured.
The method of claim 4, wherein

The distance (D) between the target and the object has a value of 0.9 times or less of the average free path (λ).
The method of claim 5,

And a distance between the limiter and the object is smaller than a distance between the target and the limiter.
The method of claim 4, wherein

The limiter is an electronic material film forming apparatus, characterized in that the cross section between the plurality of slits and the outside of the both ends slits have a curved structure.
The method of claim 4, wherein

The process gas particle of the said sputtering process is argon, The value (P * D) which multiplied the distance (D) between the said target and the object by the said sputtering pressure (P) is 0.01 Torr * mm or more, 0.42Torr * mm or less, It is characterized by the above-mentioned. Electronic material film forming apparatus.