WO2008002046A1

WO2008002046A1 - Apparatus and method for generating solid element neutral particle beam

Info

Publication number: WO2008002046A1
Application number: PCT/KR2007/003070
Authority: WO
Inventors: Suk-Jae Yoo; Bong-Ju Lee
Original assignee: Korea Basic Science Institute
Priority date: 2006-06-29
Filing date: 2007-06-25
Publication date: 2008-01-03
Also published as: KR100716258B1

Abstract

There is provided an apparatus for generating solid element neutral particle beam. The apparatus comprises a) a plasma discharging space inside which a plasma discharge takes places to produce plasma, b) a solid element coating layer positioned at side of the plasma discharging space to which a first bias voltage is applied to drive plasma ions to the solid element coating layer, c) a first magnetron unit that applies magnetic field across the solid element coating layer, and d) a metal plate positioned at top of the of the plasma discharging space to which a second bias voltage is applied to drive solid element cations to the metal plate. Preferably, the apparatus further comprises a second magnetron unit that applies magnetic field across the metal plate. Par¬ ticularly preferable is that each of the first and second magnetron units comprises a central pole and a side pole having a race track arrangement. The apparatus is useful for surface treatment.

Description

APPARATUS AND METHOD FOR GENERATING SOLID ELEMENT NEUTRAL PARTICLE BEAM

Technical Field

[1] The present invention relates to an apparatus for generating solid element neutral particle beam. More particularly, the present invention relates an apparatus for generating solid element neutral particle beam by using a pure solid matter of solid element, rather than by using a solid element-containing gas. Background Art

[2] One exemplary embodiment of conventional methods widely used in thin film growth of solid element, such as silicon deposition, carbon nano-tube growth and ion implanting, comprises heating a target to a very high temperature, and contacting a solid element-containing gas to the target such that the solid element-containing gas undergoes a pyrolysis and solid atoms produced are deposited onto the target. However, this method requires heating of the target to the very high temperature, and its application is highly limited.

[3] Another exemplary embodiment of the conventional methods widely used in thin film growth is to use plasma of a solid element-containing gas. Specifically, a high voltage is applied to the solid element-containing gas to produce plasma and the plasma produced collides with a target to accomplish thin film deposition. However, the method suffers from disadvantages that highly pure thin film growth is unattainable, due to impurities produced from additional components contained in the gas other than the solid element. In order to accomplish high purity, very high temperature is required to the target.

[4] For instance, in order to accomplish carbon nano-tube growth, methane (CH ) is used as a carbon source. However, four hydrogen elements present in the methane gas act as an impurity. For silicon deposition, silane (SiH ) containing a silicon element is used. However, the silane is a highly toxic gas, and four hydrogen elements present in the silane gas produce impurities. Likewise, PH , AsH , and BF are used in ion implantation. These gases are very strong poisonous gases, so very strict equipment standard is required. Further, additional processes, such as high temperature heating, are required during implantation, to eliminate adverse effects caused from impurities (hydrogen elements or fluorine elements).

[5] WO 2005/117077 owned by the present inventors discloses a solid element plasma source comprising a first chamber inside which sputtering of solid atoms is performed by collision of a solid lump with accelerated particles or lasers followed by detachment of solid atoms from the solid lump and a second chamber connected to the first chamber inside which plasma discharge is performed by application of a voltage that initiates plasma discharge of the sputtered solid. The solid element plasma source provides basis to avoid the problems caused by use of the solid element-containing gas. Disclosure of Invention Technical Problem

[6] An object of the present invention is to provide an apparatus for generating solid element neutral particle beam that avoids the problems caused by use of a solid element-containing gas, such as generation of impurities and harmfulness of poisonous gases.

[7] Another object of the present invention is to provide an apparatus for generating solid element neutral particle beam that provides enhanced improvement to a solid element plasma source of WO 2005/117077. Technical Solution

[8] According to the preferred embodiment of the present invention, there is provided an apparatus for generating solid element neutral particle beam, comprising a) a plasma discharging space inside which a plasma discharge takes places to produce plasma that is a group of plasma ions and electrons, b) a solid element coating layer positioned at side of the plasma discharging space to which a first bias voltage is applied to drive the plasma ions produced from the plasma discharge to the solid element coating layer, c) a first magnetron unit that applies magnetic field across the solid element coating layer, and d) a metal plate positioned at top of the of the plasma discharging space to which a second bias voltage is applied to drive solid element cations to the metal plate.

[9] According to more preferred embodiment of the present invention, there is provided an apparatus for generating solid element neutral particle beam, further comprising a second magnetron unit that applies magnetic field across the metal plate.

[10] According to another more preferred embodiment of the present invention, there is provided an apparatus for generating solid element neutral particle beam, wherein each of the first and second magnetron units comprises a central pole and a side pole having a race track arrangement into which the side pole surrounds the central pole.

[11] According to further another more preferred embodiment of the present invention, there is provided an apparatus for generating solid element neutral particle beam, wherein each of the first and second magnetron units is covered with a cover made of magnetic shielding agent to reinforce the magnetic field at inside of the plasma discharging space.

[12] According to another preferred embodiment of the present invention, there is provided an apparatus for generating solid element neutral particle beam, further comprising a magnetic unit or an electric unit positioned at outside of side wall of the apparatus to eliminate side effects caused by the plasma ions and electrons.

[13] According to another preferred embodiment of the present invention, there is provided an apparatus for generating solid element neutral particle beam, further comprising a plasma limiter positioned below the plasma discharging space. The plasma limiter is configured to have holes or slits to pass the neutral particles through while interrupting the plasma ions and electrons from passing through. The plasma limiter may further comprise a magnetic unit or an electric unit to the holes or slits in order to change pathways of the plasma ions and the electrons.

[14] According to another preferred embodiment of the present invention, there is provided an apparatus for generating solid element neutral particle beam, further comprising a collimator, positioned below the plasma limiter to collimate neutral particles which had passed through the plasma limiter. The collimator is configured to have holes to collimate the neutral particles.

Advantageous Effects

[15] The neutral particle beam generating apparatus of the present invention produces neutral particle beam in simple and efficient manner, compared with the conventional solid element plasma source and solid element neutral particle source. No solid element-containing gas is used. Therefore, the problems caused from the use of the solid elements-containing gas can be avoided. No toxic gas is used. The present invention adopts the technical advantages of WO 2005/117077, and provides even advanced neutral particle beam generating apparatus.

[16] The neutral particle beam generating apparatus of the present invention has simple structure and improved neutral particle beam flux. For instance, the apparatuses disclosed in WO 01/84611 and WO 2004/036611 had complicatedly structured reflecting panels in order to achieve conversion of plasma ions into neutral particles and exclusion of interference by plasma ions and electrons. To the contrary, the apparatus according to the present invention does not require such a complicated structure. The metal plate which converts solid element cations into neutral particles and the plasma limiter which allows the neutral particles to passing through and prohibits the plasma ions and electrons from passing through are separated by the plasma discharging space. Therefore, the conversion to neutral particles could be simplified and the interruption caused by the plasma ions and the electrons are easily prevented. As a result, the conversion efficiency to the neutral particles and the surface treatment efficiency are remarkably improved.

[17] Further, according to the present invention, the distribution of the plasma ions is suitably controlled by the magnetron unit, which further increases the flux of the neutral particles. Ten fold increases in terms of the flux of the neutral particles can be obtained compared with the conventional apparatus of WO 2005/053365. Particularly, the apparatus of the present invention with improved flux of the neutral particles can be suitably applicable to various semi-conductor surface treatments including thin film deposition, pattern formation, etching, ashing, oxidized film formation and cleaning. Brief Description of the Drawings

[18] Fig. 1 is a cross-sectional view showing a preferred embodiment of the neutral particle beam generating apparatus in accordance with the present invention.

[19] Fig. 2 is a cross-sectional view showing another preferred embodiment of the neutral particle beam generating apparatus in accordance with the present invention.

[20] Fig. 3 is a cross-sectional view showing further another preferred embodiment of the neutral particle beam generating apparatus in accordance with the present invention.

[21] Fig. 4 is a perspective view showing preferred combination of a plasma limiter and a collimator used in the neutral particle beam generating apparatus in accordance with the present invention.

[22] Fig. 5 is a perspective view showing preferred embodiment of the arrangement of the magnetron unit used in the neutral particle beam generating apparatus in accordance with the present invention.

[23] Fig. 6 is a cross-sectional view showing preferred embodiment of the plasma limiter used in the neutral particle beam generating apparatus in accordance with the present invention.

[24] Fig. 7 is a graph showing resistivity of thin film deposition of the neutral particle beam generating apparatus in accordance with the present invention, compared with those of plasma enhanced this film deposition and of heat deposition.

[25] Fig. 8 is a graph showing transparency of thin film deposition of the neutral particle beam generating apparatus in accordance with the present invention, compared with those of plasma enhanced this film deposition and of heat deposition. Mode for the Invention

[26] According to the preferred embodiment of the present invention, there is provided an apparatus for generating solid element neutral particle beam, comprising a) a plasma discharging space inside which a plasma discharge takes places to produce plasma that is a group of plasma ions and electrons, b) a solid element coating layer positioned at side of the plasma discharging space to which a first bias voltage is applied to drive the plasma ions produced from the plasma discharge to the solid element coating layer, c) a first magnetron unit that applies magnetic field across the solid element coating layer, and d) a metal plate positioned at top of the of the plasma discharging space to which a second bias voltage is applied to drive solid element cations to the metal plate.

[27] Inside the plasma discharging space, processing gases are introduced and converted to plasma through a plasma discharge. In other words, plasma, as a group of plasma ions (or positive ions) and electrons, is generated within the plasma discharging space. At this point, the plasma could be generated through various methods. For instance, a capacitatively coupled plasma discharge, an inductively coupled plasma discharge, a helicon discharge using plasma wave, and a microwave plasma discharge can be applied. The inductively coupled plasma discharge which generates high density plasma under low operating pressure is desirable among them. Concerning the shapes of antenna used for the inductive coupled plasma discharge, please refer to Korean Patent Application Nos. 7010807/2000, 14578/1998, 35702/1999 and 43856/2001.

[28] The plasma ions produced inside the plasma discharging space are driven to the solid element coating layer positioned at side of the plasma discharging space. This can be easily carried out by applying a minus bias voltage to the solid element coating layer. Preferably, magnetic field is further applied into the plasma discharging space across the solid element coating layer. The first magnetron unit positioned at rear of the solid element coating layer applies the magnetic field to the plasma discharging space across the solid element coating layer. The magnetic field applied across the solid element coating layer provides high density of the plasma ions near the solid element coating layer. Particularly, the magnetic field applied by the first magnetron unit having race track arrangement in which a central pole is surrounded by a side pole forces the electrons to circulate around a mirror race track formed inside the plasma discharging space. The electrons circulating around the race track collide with neighboring neutral gases, which are not converted into the plasma, to produce plasma ions of the neighboring neutral gases. This increases the density of the plasma ions near the solid element coating layer. In order to reinforce the magnetic field at inside of the plasma discharging space, the first magnetron unit is preferably covered with a cover made of magnetic shielding agent. The plasma ions of the processing gases are driven to the solid element coating layer with aid of the minus bias voltage applied to the solid element coating layer and undergo collisions with the solid element coating layer. The collisions of the plasma ions with the solid element coating layer detach atoms of the solid element from the solid element coating layer and sputters the atoms of the solid element into the plasma discharging space in cationic or neutral state.

[29] The atoms of the solid element sputtered as a cationic state ("solid element cations") into the plasma discharging space are driven to the metal plate positioned at top of the plasma discharging space. This can be easily carried out by applying a minus bias voltage to the metal plate. Meanwhile, the atoms of the solid element sputtered as a neutral state are converted into solid element cations by the plasma discharge or by collisions with electrons. Preferably, a magnetic filed is applied to the plasma discharging space across the metal plate in order to increase the efficiency of the conversion of the sputtered neutral atoms of the solid element into plasma ions. To attain this, a second magnetron unit is positioned above the metal plate. Preferably, the second magnetron unit also comprises a central pole and a side pole having a race track arrangement into which the side pole surrounds the central pole. The magnetic field applied across the metal plate captures electrons around a mirror race track formed inside the plasma discharging space. The electrons circulating around the race track collide with the sputtered neutral solid atoms to produce plasma ions thereof. This increases the density of the solid element cations near the metal plate. As mentioned above, the solid element cations are directed to the metal plate with aid of the minus bias voltage applied to the metal plate.

[30] The metal plate converts the solid element cations to neutral particles by collisions with the solid element cations. Preferably, the surface of the metal plate, where the solid element cations collide, is polished in order to guarantee elastic collisions. The metal plate may be made of tantalum (Ta), molybdenum (Mo), tungsten (W), gold (Au), platinum (Pt), stainless steel or alloys thereof, but are not limited thereto. Contrary to that of WO 01/84611 and WO 2004/036611, the metal plate does not require any holes for the pathway of neutral particles. That is because, although the metal plate collides with plasma ions to convert the plasma ions to neutral particles, it does not function as a pathway for the produced neutral particles.

[31] The neutral particles produced by collisions of the solid element cations with the metal plate are reflected, and are driven via the plasma discharging space to a substrate located below plasma discharging space to perform surface treatment of the substrate.

[32] As used herein, the term "surface treatment" includes thin film deposition, thin film growth, pattern formation, etching, ashing, oxidized film formation and cleaning. To accomplish this, the solid element coating layer is formed of pure solid matter of the solid elements, for example a single solid element such as carbon (C), phosphine (P), arsine (As), gallium (Ga), silicon (Si), indium (In), titanium (Ti), aluminum (Al), cupper (Cu), silver (Au) and gold (Au), and composite thereof such as GaAs, InSnO, stainless steel and SiC.

[33] In a meanwhile, to prevent the plasma ions and the electrons from reaching to the substrate, a magnetic field or an electric field may further applied to between the plasma discharging space and a treating room that houses the substrate to be treated. To apply the magnetic field or the electric unit, a magnetic unit or electric unit may be installed at outside of the side wall of the neutral particle generating apparatus. [34] More preferably, a plasma limiter that prevents damage to the substrate by the plasma ions and the electrons is installed at between the plasma discharging space and a treating room. The plasma limiter interrupts the plasma ions and the electrons from passing through and selectively allows the neutral particles to pass through. A passive limiting using holes or slits to limit the plasma ions and the electrons from passing through, or an active limiting in which magnetic or electric field is impressed on the holes or slits to change the pathways of the charged plasma ions or electrons could be used.

[35] In order to form a pre-determined pattern on the substrate, the directionality of neutral particles needs to be suitably controlled. For instance, to form a predetermined pattern on the surface of the substrate, the directionality of neutral particles is very important. In this case, it is desirable to additionally install a collimator, which collimates the direction of neutral particles, at between the plasma limiter and the treating room. The collimator is configured to have multi holes to provide fixed directionality.

[36] The present invention also relates to a surface treatment method using the solid element neutral particle beam, comprising a) introducing a processing gas into a plasma discharging space, b) converting the processing gas into plasma through a plasma discharge inside the plasma discharging space, c) colliding plasma ions of the plasma with a solid element coating layer positioned at side of the plasma discharging space to sputter atoms of solid element from the solid element coating layer, d) driving solid element cations to a metal plate positioned at top of the plasma discharging space, e) colliding solid element cations with the metal plate to produce solid element neutral particles, and f) contacting the solid element neutral particles with a substrate to achieve surface treatment of the substrate. Herein, sputtering of the atoms of the solid element from the solid element coating layer can be further increased by applying magnetic field to the plasma discharging space across the solid element coating layer. In order to eliminate adverse effects from the plasma ions and electrons produced inside the plasma discharging space, the method may further comprises the step of penetrating the neutral particles of the solid atoms through a plasma limiter positioned below the plasma discharging space and configured to have holes or slits, between the steps e) and f). Further, to increase directionality of the neutral particles of the solid atoms, the method may further comprise the step of penetrating the neutral particles of the solid atoms that had passed through the plasma limiter through a collimator positioned below the plasma limiter.

[37] In the following, the present invention will be more fully described referring to accompanying drawings.

[38] Fig. 1 is a cross sectional view showing a preferred embodiment of the solid element neutral particle beam generating apparatus in accordance with the present invention. The apparatus illustrated in Fig.1 is comprised of a reaction chamber 100 with an opened lower part and a treating room 300 below the reaction chamber. The inner space of the reaction chamber 100 is a plasma discharging space 101. An antenna 102 to supply high frequency energy is installed in the plasma discharging space 101 and a gas inlet port (not shown) is installed at a side of the reaction chamber 100. At side of the plasma discharging space 101, solid element coating layers 104a, 104b (totally "104") is positioned. The solid element coating layer 104 may be a metal film onto which atoms of solid element having solid state are coated. If necessary, the solid element coating layer 104 may be formed by coating the solid matter of the solid element directly to inner side wall of the reaction chamber 100, which is shown in Fig. 2. To the solid element coating layer 104, a minus bias voltage is applied. At rear of the solid element coating layer 104, a first magnetron unit 500 is installed.

[39] The reaction chamber 100 is operated as follows. First, a processing gas is introduced into the plasma discharging space 101 through the gas inlet port (not shown) and the processing gas undergoes a plasma discharge with aid of high power supplied through the antenna 102 and is converted into plasma 103, a group of plasma ions (cations) 103b and electrons 103a.

[40] Herein, the distribution of the plasma 103 is suitably controlled by the magnetic field applied to the plasma discharging space 101 across the metal plate 106. To accomplish this, the first magnetron unit 500 is installed at the rear of the solid element coating layer 104. Preferred embodiment of the arrangement of the first magnetron unit

500 is shown in Fig. 5. As shown in Fig. 5, the first magnetron unit 500 is comprised of a central pole 501 and a side pole 502 having a race track arrangement into which the side pole 502 surrounds the central pole 501. Herein, the upper of the central pole

501 has N pole (or S pole) and the bottom of the central pole 501 has S pole (or N pole), and the side pole 502 has complementary arrangement to the central pole 501. If necessary, the central pole 501 may be a permanent magnet and the side pole 502 may be a magnetic absorbent body. The magnetic field applied across the solid element coating layer 104 by the first magnetron unit 500 having race track arrangement controls the movement of the electrons 103a. In other words, it forces the electrons 103a to circulate around mirror race track inside the plasma discharging space 101. The electrons 103a rotating around mirror race track collides with neutral particles of the processing gas 103c that are not converted into plasma to produce plasma ions 103b. As a result thereof, the magnetic field applied across the solid element coating layer 104 captures the electrons 103a around the race track and increase the density of the plasma ions 103b near the solid element coating layer 104. The strength of the magnetic field by the first magnetron unit 500 can be suitably adjustable depending upon the kind and the amount of the processing gas. Typically, the magnetic field having the strength of 1000 - 5000 gauss is applied. At below 1000 gauss, the strength is not enough to capture the electrons. At above 5000 gauss, it is not cost effective. The first magnetron unit 500 is generally made of the permanent magnet. In order to reinforce the magnetic field inside the plasma discharging space 101, the first magnetron unit 500 is preferably covered with a cover 700. Preferably, the cover 700 has high magnetic susceptibility to focus the magnetic field into the plasma discharging space 101 and to reduce the loss thereof. Generally, soft iron is widely used as magnetic shielding agent.

[41] The plasma ions 103b of the plasma 103 produced inside the plasma discharging space 101 are directed to the solid element coating layer 104 located at side of the plasma discharging space 101. Herein, the plasma ions 103b could be easily directed to the solid element coating layer 104 by applying a minus bias voltage to the solid element coating layer 104. The power of the bias voltage can be suitably adjustable depending upon the kind of the solid element and the processing gas. Typically, the minus bias voltage has the strength of 100 - 1000 V, preferably 500 - 1000 V. Then, the plasma ions 103b collide with the solid element coating layer 104. By the collisions of the plasma ions 103b with the solid element coating layer 104, atoms of the solid element 105 are detached and sputtered from the solid element coating layer 104 in a neutral state 105a or cationic state 105b. Generally, most of the atoms of the solid element are sputtered in a neutral state 105a.

[42] The atoms of the solid element 105 sputtered into the plasma discharging space 101 undergoes the plasma discharge at the plasma discharging space 101 or collisions with the electrons 103a near the metal plate 106 to produce solid element cations 105b.

[43] The solid element cations 105b are driven to the metal plate 106 positioned at top of the plasma discharging space 101. The solid element cations 105b could be easily directed to the metal plate 106 by applying a minus bias voltage to the metal plate 106. The bias voltage can be suitably adjustable depending upon the energy of the solid element to be required. Typically, the minus bias voltage has the strength of 10 - 100 V, preferably 10 - 50 V.

[44] Preferably, in order to increase the density of the solid element cations 105b near the metal plate 106, the magnetic field is applied across the metal plate 106. To accomplish this, a second magnetron unit 600 is installed at rear of the metal plate 106. The second magnetron unit 600 is preferably also comprised of a central pole 601 and a side pole 602 having a race track arrangement into which the side pole 602 surrounds the central pole 602. Typically, the magnetic field having the strength of 1000 5000 gauss is applied. The second magnetron unit 600 positioned at rear of the metal plate 106 captures the electrons 103a near the metal plate 106 and forces to rotate around mirror race track. The electrons 103a circulating around the race track collides with neutral atoms of the solid element (neutral solid element) 105a to produce solid element cations 105b. As a result thereof, the density of the element cations 105b near the metal plate 106 is increased. In order to reinforce the magnetic field into the plasma discharging space 101, the second magnetron unit 600 is preferably covered with a cover made of magnetic shielding agent, as like in Fig. 5.

[45] When a minus bias voltage is impressed to the metal plate 106, the solid element cations 105b are directed to the metal plate 106 substantially or perfectively perpendicularly and collide with the metal plate 106. The surface of the metal plate 106, where the solid element cations 105b collide, may be polished to improve conversion efficiency to neutral particles and to prevent energy loss during the collisions. By the collision with the metal plate 106, the solid element cations 105b undergo neutralization such as auger neutralization. The neutral particles of the solid element (solid element neutral particles) 105c thus produced are reflected and enter into a substrate 301 of a treating room 300 via the plasma discharging place 101 and perform surface treatment of the substrate 301. If necessary, the solid element neutral particles 105c may be used as a remote neutral particle source.

[46] To prevent damage to the substrate 301 by the plasma ions 103b and the electrons

103a produced inside the plasma discharging space 101, the neutral particle beam generating apparatus may further comprises a magnetic unit or an electric unit at outside of the side wall of the apparatus.

[47] In order to effectively prevent the interference by the plasma ions 103b and the electrons 103a, the neutral particle beam generating apparatus further comprises a plasma limiter 200 at between the plasma discharging space 101 and the treating room 300. The plasma limiter 200 is configured to have holes or slits 201. These holes or slits 201 allow the neutral particles to penetrate while interrupting the passage of the plasma ions and the electrons. Conclusively, the solid element neutral particles 105c could pass through the plasma limiter 200 selectively and reach to the substrate 301 located in the treating room 300. Although a material for the plasma limiter 200 is not specifically limited, a dielectric such as ceramic is desirable. The reason is that energy of the plasma ions 103b and the electrons 103a is absorbed when they collide with the side wall 202 of the plasma limiter 200 and thus, the adverse effects caused by the plasma ions 103b and the electrons 103a could be minimized. Meanwhile, the plasma limiter 200 may also collide with the neutral particles without definite directionality and absorb their energy so that any adverse effect caused by neutral particles without definite directionality can be also eliminated. The passive limiting of the plasma ions and the electrons by the holes or slits 201 is dependent upon the diameter and the depth of holes and slits 201, and such an adjustment should be suitably performed. [48] To prevent the plasma ions 103b and the electrons 103a from passing through the plasma limiter 200, a means 203 for applying magnetic field or electric field to the plasma limiter 200 could be additionally installed at the plasma limiter 200. The means for applying magnetic or electric field 203 changes the moving direction of the plasma ions and the electrons, and further prevents them from reaching to the surface of a substrate. This limiting is called as "an active limiting". Fig. 6 shows preferred embodiment of the plasma limiter 200 used in the active limiting. As shown in Fig. 6, the plasma limiter 200 preferably comprises a magnet 203a at a center to apply the magnetic field into the holes or slits 201, conductive metal membranes 203b positioned at both surfaces of the magnet 203a to apply the electric field into the holes or slits 201, and dielectric membranes 204 positioned at both surfaces of the conductive metal membranes 203b to insulate the conductive metal membranes 203b. In order to reduce the loss of the magnetic field applied by the magnet 203a, a magnetic shielding film (not shown) may be formed at bottom of the magnet 203a. As a magnetic shielding agent, any one well known in the art may be used. Preferable is soft iron. The conductive metal membranes 203b is connected to a power supply (not shown), and each of the dielectric membranes 204 may be formed of an insulating material or by oxidizing the surface of the conductive metal membrane 203b. The conductive metal membrane 203b may be partially formed at surface of the magnet 203b. If necessary, the magnetic shielding film may be used as conductive metal membrane 203b. Preferably, the strength of the magnetic field is 1000 - 5000 gauss, and the strength of the electric field is 10 - 100 V having higher potential than that of the plasma discharging space.

[49] The solid element neutral particles 105c, which are protected from interruptions of the plasma ions and the electrons by "the passive limiting" or "the active limiting", perform surface treatment of the substrate 301 installed inside the treating room 300. For instance, the solid element neutral particles 105c may be used for thin film growth, thin film deposition or pattern formation on the substrate 301. At this point, the neutral particles are not charged particles and they cause no damage to the substrate 301. The unexplained reference number 302 is a target holder moving up and down by operation of an elevating device connected to a elevating axis (not shown) so that it can carry in the substrate 301 such as a wafer to be newly processed and carry out the processed substrate 301. Meanwhile, the target holder 302 may be horizontally moved by a motor (not shown). This can prevent forming a blind spot caused by local introduction of the neutral particles onto the surface of the wafer. The unexplained reference number 303 is a gas outlet port connected to a vacuum pump (not shown) and maintains the inner pressure of the treating room 300 at about 1 mTorr.

[50] Although Fig. 1 shows an example of plasma generation by the inductively coupling plasma discharge, a capacitatively coupled plasma discharge, a helicon discharge using plasma wave and a microwave plasma discharge could be widely applied, under the condition of in situ generation of plasma ions by a discharge in the plasma discharging space and neutral particles generation by collisions of the produced plasma particles with the metal plate. Besides the various applications of the plasma discharging techniques, the plasma ions could be directed to the metal plate 106 by applying a plus bias voltage to the reaction chamber 100, instead of applying the minus bias voltage to the metal plate 106. Applying a minus bias voltage directs the positively charged plasma ions to the metal plate 106 by attraction. To the contrary, a plus bias voltage directs the plasma ions to the metal plate 106 by repulsion.

[51] According to the solid element neutral particle beam generating apparatus of the present invention, an additive gas may be additionally supplied into the treating room 300 in combination with the neutral particles of the solid element in order to assist surface treatment. This is specifically explained in WO 2004/036611.

[52] In the above, the solid element neutral particle beam generating apparatus comprises the metal plate 106 installed above the plasma discharging space 101, but it is also possible to use the inner upper wall of the reaction chamber 100 as a metal plate 106 by being formed of a metal or coating a metal thereon. Further, the solid element coating layer 104 may be formed at inner side wall of the apparatus. Fig. 2 shows such an example. In Fig. 2, instead of additionally installing the metal plate 106, the inner upper wall of the reaction chamber 100 coated with a metal is used as the metal plate 106, and a minus bias voltage is applied thereto. With the collisions of plasma ions 103b with the solid element coating layer 104, atoms of the solid element are sputtered in a neural or cationic state. Thereafter, with the aid of the minus bias voltage, solid element cations 105b in the plasma discharging space 101 is directed to the metal- coated inner upper wall that acts as the metal plate 106, and produce solid element neutral particles 105c by collisions therewith. Herein, the inner upper wall is insulated electrically with the other side walls of the reaction chamber 100 by insulators 107' 107". The reference numerals, which are not specifically explained, are the same as those of the solid element neutral particle beam generating apparatus shown in Fig. 1.

[53] Fig. 3 shows further another preferred embodiment of the solid element neutral particle beam generating apparatus in accordance with the present invention. The apparatus illustrated in Fig. 3 is comprised of a reaction chamber 100 with an opened lower part, a plasma limiter 200 located at the opened lower part of the reaction chamber 100, a treating room 300 located below the plasma limiter 200 and a collimator 400 located at between the plasma limiter 200 and the treating room 300. Explanation to the reaction chamber 100, the plasma limiter 200 and the treating room 300 is omitted because they are the same as those described in Fig. 1. The collimator 400, located between the plasma limiter 200 and the treating room 300, collimates the solid element neutral particles 105c passed through the plasma limiter 200 to improve the directionality of the neutral particles. The collimator 400 is configured to have multi holes 401. The solid element neutral particles which had collided with the side wall 402 of the holes 401 more than once loose their energy during collision, and can no longer perform their role. Therefore, of the neutral particles which had penetrated the collimator 400, the ones perpendicular to the holes 401 can be solely used. As thus, the directionality of the neutral particles is improved by the collimator 400.

[54] Fig. 4 is a perspective view showing a preferred combination of the plasma limiter and the collimator. The plasma limiter 200 in Fig.4 has slits formed between flat panels 204 formed of ceramic, and the collimator 400 has holes 401 at a position corresponding to the slits 201 of the plasma limiter 200. The slits 201 formed in the plasma limiter 200 improve the penetrating efficiency of the neutral particles, and the plasma ions and the electrons are interrupted from passing through the slits 201 by impressing the magnetic field created by the magnet 203. And holes 401 formed in the collimator 400 improve the directionality of the neutral particles. Interference by the plasma ions and the electrons is effectively excluded by the combination, and the neutral particles having collimated directionality perform surface treatment of the substrate. The neutral particles with improved directionality by the combination can be usefully applicable to various surface treatments. For instance, the neutral particle beams can be applied to pattern formation or lithography on a substrate 301 with a stencil mask. Meanwhile, although the plasma limiter 200 and the collimator 400 are presented as a hexahedron shape in Fig.4, it can be changed to various shapes such as cylindrical or oval shape.

[55] According to the present invention, pure solid matter of the solid element is used as a source of the solid element. In the prior art, solid element-containing gases were used to produce a solid element plasma. However, the prior art was suffered from impurities and toxicity of the gases. For example, in the prior art, methane (CH ) was used as a source of a carbon atom, silane (SiH ) as a source of a silicon atom, boron trifluoride

4

(BF ) as a source of a boron atom, phosphine (PH ) as a source of a phosphor atom and arsine (AsH 3 ) as a source of an arsenic atom, respectively. When the gases are used, however, other atoms (hydrogen or fluoride) composing the gases act as impurities. Furthermore, silane (SiH ), boron trifluoride (BF ) and phosphine (PH ) are highly

4 3 3 toxic material and any danger of gas leakage needs to be completely protected. But, the present invention uses the pure solid matter of the solid element. It eliminates adverse effects caused by other components contained in a gas other than carbon atom. Therefore, heating of a target to remove impurities is not required. Moreover, as a consequence, damages to the target, which may be caused by thermal expansion, could be reduced. Since no poisonous gas is used, the working environment could be improved. The solid element coating layer 104 is formed of pure solid matter of the solid elements, for example a single solid element such as carbon (C), phosphine (P), arsine (As), gallium (Ga), silicon (Si), indium (In), titanium (Ti), aluminum (Al), cupper (Cu), silver (Au) and gold (Au), and composite thereof such as GaAs, InSnO, stainless steel and SiC. In a meanwhile, Figures 1 to 3 exemplify the embodiments in which two solid element coating layers 104 were equipped with. But, this is just an example. The number of the solid element coating layer 104 can be suitably adjustable regarding various operation conditions such as the kind of the solid element to be used, the density of the solid element to be required, and the strength of the magnetic field and the electric field to be applied. If necessary, only one solid element coating layer 104 may be used. Preferably, the solid element coating layers 104 are used in a range of 2 - 4, having a symmetric arrangement. The symmetric arrangement increases the uniformity of the solid element neutral particle beam.

[56] EXAMPLE

[57] Deposition on ITO film was performed using the solid element neutral particle beam generating apparatus as shown in Fig. 1. The minus bias voltage applied to the metal plate was 50V. For the purpose of comparison, plasma enhanced deposition and heat deposition were also carried out, respectively. The temperature of the heat deposition was 28O⁰C. The results thereof were summarized in Figures 7 and 8. Fig. 7 shows resistivity test result and Fig. 8 shows transparency test result. In Figures 7 and 8, HNB denotes the solid element neutral particle beam generating apparatus of the present invention, PE denotes plasma enhanced thin film deposition, and Heat denotes heat deposition, respectively. As shown in Figures 7 and 8, the solid element neutral particle beam generating apparatus of the present invention exhibited more improved performance.

[58] As described, it should be evident that the present invention can be implemented through a variety of configurations in the aforementioned technical field without affecting, influencing or changing its spirit and scope of the invention. Therefore, it is to be understood that the examples and applications illustrated herein is intended to be in the nature of description rather than of limitation. Furthermore, the meaning, scope and higher conceptual understandings of the present patent application as well as modifications and variations that arise from thereof should be understood to be extensions to this current application.

Claims

[1] An apparatus for generating solid element neutral particle beam, comprising a) a plasma discharging space inside which a plasma discharge takes places to produce plasma that is a group of plasma ions and electrons, b) a solid element coating layer positioned at side of the plasma discharging space to which a first bias voltage is applied to drive the plasma ions produced from the plasma discharge to the solid element coating layer, c) a first magnetron unit that applies magnetic field across the solid element coating layer, and d) a metal plate positioned at top of the of the plasma discharging space to which a second bias voltage is applied to drive solid element cations to the metal plate.

[2] The apparatus as set forth in claim 1, further comprising a second magnetron unit that applies magnetic field across the metal plate.

[3] The apparatus as set forth in claim 2, wherein each of the first and second magnetron units comprises a central pole and a side pole having a race track arrangement into which the side pole surrounds the central pole.

[4] The apparatus as set forth in claim 3, wherein each of the first and second magnetron units is covered with a cover made of magnetic shielding agent to reinforce the magnetic field applied to inside of the plasma discharging space.

[5] The apparatus as set forth in claim 1, further comprising a plasma limiter positioned below the plasma discharging space and configured to have holes or slits.

[6] The apparatus as set forth in claim 5, wherein the plasma limiter further comprises a member selected from a magnetic unit to impress magnetic field and an electric unit to impress electric field to the holes or the slits, to change pathways of the plasma ions and electrons.

[7] The apparatus as set forth in claim 5, further comprising a collimator positioned below the plasma limiter and configured to have multi holes to collimate neutral particles which had passed through the plasma limiter.

[8] A method for the surface treatment of a substrate using the solid element neutral particle beam, comprising: a) introducing a processing gas into a plasma discharging space; b) converting the processing gas into plasma through a plasma discharge inside the plasma discharging space; c) colliding plasma ions of the plasma with a solid element coating layer positioned at side of the plasma discharging space to sputter atoms of solid element from the solid element coating layer; d) driving solid element cations to a metal plate positioned at top of the plasma discharging space; e) colliding solid element cations with the metal plate to produce solid element neutral particles; and, f) contacting the solid element neutral particles with a substrate to achieve surface treatment of the substrate.

[9] The method as set forth in claim 8, wherein the sputtering of atoms of solid element of the step c) is assisted by a first magnetron unit that applies magnetic field across the solid element coating layer and the production of solid element neutral particles of the step e) is assisted by a second magnetron unit that applies magnetic field across the metal plate.

[10] The method as set forth in claim 9, wherein each of the first and second magnetron units comprises a central pole and a side pole having a race track arrangement into which the side pole surrounds the central pole.