JP4473852B2 - Sputtering apparatus and sputtering method - Google Patents

Description

  The present invention relates to a sputtering apparatus and a sputtering method used to produce a thin film on a substrate, and in particular, on an organic thin film that requires low-temperature and low-damage film formation, or the substrate is a polymer material. The present invention relates to a sputtering apparatus and a sputtering method for producing a highly functional thin film made of a metal, an alloy, a compound, or the like on a film or a resin substrate. Specific application fields include transparent conductive films and sealing films (gas barrier films) for organic EL (organic electroluminescence) elements. In addition, a transparent conductive film, a metal film, a protective film, and a metal film and a protective film on an organic thin film (for example, an organic thin film semiconductor) are formed on the polymer film. Furthermore, it can also be used in general-purpose thin film production fields (electronic parts, magnetic head parts, etc.) in which a thin film is produced on a substrate using conventional opposed target type cathodes and inclined type cathodes (V type cathodes). .

  Conventionally, in order to produce a thin film on a substrate, for example, as shown in FIG. 15, a counter target sputtering apparatus 50 for forming a film on a substrate 52 using a pair of targets (target plates) 51a and 51b, and A sputtering method is used. In the sputtering apparatus 50 and the sputtering method for forming a film on the substrate 52 using the pair of targets 51a and 51b, the targets 51a and 51b have sputtering surfaces 51a ′ and 51b ′, respectively, Both sputter surfaces 51a ′ and 51b ′ are arranged in parallel at a predetermined interval so as to face each other.

  Then, by arranging the magnets 55a and 55b on the back side (the side opposite to where the target is fixed) of the backing plates (back plates) 54a and 54b that respectively fix the pair of targets 51a and 51b, A magnetic field is generated in a direction perpendicular to the respective sputtering surfaces 51a ′ and 51b ′ of the pair of targets 51a and 51b, the pair of targets 51a and 51b is sputtered, and the pair of sputtered targets 51a and 51b The sputtered particles scattered from 51b are formed on the substrate 52 which is provided so that the deposition surface 52 'faces the space formed between the two sputtering surfaces 51a' and 51b 'by the pair of targets 51a and 51b. A film is formed on the substrate 52 by being attached to the deposition surface 52 ′.

  However, such a sputtering apparatus 50 and sputtering method can form a film in a so-called plasma-free state in which the impact is hardly received by charged particles such as secondary electrons and negative ions emitted from the surfaces of the targets 51a and 51b. The sputtered particles are likely to diverge in all regions other than the substrate 52, and the film formation rate is low and the cost for film formation is high compared to the conventional magnetron sputtering apparatus and sputtering method. In addition, sputtered particles may adhere to the inner surface of the vacuum vessel other than the substrate, reducing the utilization efficiency of the target material and complicating the maintenance.

Therefore, the directivity of the flight of the sputtered particles to the substrate side is increased by inclining the pair of targets so that both of the sputter surfaces face the film-forming surface of the substrate, in other words, the substrate. A counter-target type sputtering apparatus and sputtering method using a so-called V-type cathode capable of suppressing the divergence to regions other than the above, thereby increasing the deposition rate on the substrate and improving the utilization efficiency of the target material. (See Patent Document 1).
Japanese Patent Laid-Open No. 2004-285445

  By the way, in the film formation by the facing target type (including V-type cathode) sputtering apparatus and sputtering method in which the magnet is arranged on the back side of each backing plate as described above, the plasma is formed between a pair of targets. One of the characteristics is that the substrate can be formed in a state in which the substrate is hardly affected by plasma, that is, in a so-called plasma-free state, by confining in a magnetic field space.

  However, even with this facing target sputtering apparatus and sputtering method, the confinement of the plasma by the inter-target magnetic field space formed between the pair of targets is not perfect, and the influence of the plasma may reach the substrate. Further, charged particles such as secondary electrons and negative ions from the sputtering surfaces (surfaces of the pair of targets facing each other) flying toward the film formation surface of the substrate cannot be completely prevented.

  For this reason, particularly when an electrode film or a protective film is formed on an organic thin film that requires low temperature and low damage film formation, the temperature of the substrate rises due to the influence of plasma between the targets. The film quality of the formed thin film deteriorates, and the substrate is damaged by charged particles such as secondary electrons and negative ions flying from the sputtering surface to the substrate, and the function of the thin film formed on the substrate is lattice irregular. In some cases, the problem may be reduced due to distortion.

  In addition, in order to solve the above problem, by setting the distance between the centers of the targets to be short, the magnetic field strength (magnetic field strength) at the center between the targets is increased, so that plasma, secondary electrons, etc. It is conceivable to confine it in the formed magnetic field space, but in that case, the distance between the centers of the targets is shortened, that is, the distance between the pair of targets is narrowed. As the number of sputtered particles decreases, the substrate film-forming area decreases, resulting in a problem of reduced productivity.

  Therefore, in view of the above problems, the present invention provides a counter particle type sputtering apparatus and sputtering method in which charged particles such as plasma and secondary electrons formed between targets without shortening the distance between the centers of a pair of targets. It is an object of the present invention to provide a sputtering apparatus and a sputtering method capable of forming a film at a low temperature and a low damage by increasing the confinement effect between the targets.

Therefore, in order to solve the above problems, facing target sputtering apparatus according to the present invention, between a pair of targets arranged so as to face each other with a spacing, between the targets for generating a target inter-field space magnetic field generating means is provided, said pair of targets, to face the deposition surface of the substrate to be film-forming target disposed on one lateral position of the pair of targets, by inclining the surfaces facing each other The inter-target magnetic field generating means is arranged in the opposed target type sputtering apparatus in which the polarity is set so that the magnetic field lines in the inter-target magnetic field space are directed from one target to the other target. further comprising, said auxiliary magnetic field generating means an auxiliary magnetic field generating means for generating an auxiliary magnetic field space in a position such that, the A pair of cylindrical permanent magnets will be positioned along the periphery so as to surround each of the pair of targets, setting the polarity as the magnetic field lines are directed in the same direction as the magnetic field lines in the target between the magnetic field generation space in the auxiliary magnetic field space Each of the permanent magnets of the auxiliary magnetic field generating means is formed such that a bottom wall, which is a peripheral wall on the substrate side, is thicker than a top wall, which is a peripheral wall on the opposite side, and the inter-target magnetic field space and the substrate The bottom wall is disposed between the target and the substrate so as to generate the auxiliary magnetic field space at a position where the space is blocked.

  According to such a configuration, the auxiliary magnetic field space is formed along the inter-target magnetic field space formed (generated) by the inter-target magnetic field generating means by the auxiliary magnetic field generating means arranged around each target of the pair of targets. (Occurs). The auxiliary magnetic field space is at least at a position that blocks between the inter-target magnetic field space and the substrate to be deposited, and the magnetic field lines in the auxiliary magnetic field space are in the same direction as the magnetic field lines in the inter-target magnetic field space. Formed (occurs).

  Thus, the auxiliary magnetic field generating means is separately arranged around the inter-target magnetic field generating means, and the auxiliary magnetic field space is formed along the inter-target magnetic field space, thereby shortening (smaller) the distance between the centers of the pair of targets. Without doing so, it is possible to increase the magnetic field strength at the center between the targets. Therefore, the confinement effect of plasma between targets and the confinement effect of charged particles such as secondary electrons between targets are improved.

  That is, the auxiliary magnetic field generating means is separately arranged, so that an auxiliary magnetic field space is further formed at least on the substrate side outside the inter-target magnetic field space. For this reason, a space having a high magnetic flux density (confinement described later) formed on the substrate side from a line connecting the centers of the opposing sputtering surfaces of the pair of targets to each other (hereinafter sometimes simply referred to as “TT line”). The distance to the edge of the magnetic field space (the width of the confined magnetic field space) increases, and the magnetic field space (hereinafter simply referred to as the “confined magnetic field”) in which the plasma is composed of the inter-target magnetic field space and the auxiliary magnetic field space formed outside the target magnetic field The space is sometimes confined in the confined magnetic field space without protruding from the space. As described above, since the plasma is confined in the confined magnetic field space, the influence of the plasma on the substrate can be reduced.

Also, charged particles such as secondary electrons that jump out from the inter-target magnetic field space to the substrate side will jump out because the width of the confined magnetic field space is larger than the inter-target magnetic field space by the auxiliary magnetic field space. The moving distance of the charged particles in the confined magnetic field space increases. For this reason, the effect of confining charged particles in the confined magnetic field space is increased. That is, jumping of charged particles from the confined magnetic field space to the substrate side is reduced. The confined magnetic field space is a combined magnetic field space of the inter-target magnetic field space and the auxiliary magnetic field space, and the inter-target magnetic field space and the auxiliary magnetic field space pass through a space having a small magnetic flux density (the magnetic flux density is equal to or less than a predetermined value). The inter-target magnetic field space and the auxiliary magnetic field space may be formed integrally (so that the magnetic flux density is the same or continuously and changes at a predetermined value or more). May be.

Further, each permanent magnet of the auxiliary magnetic field generating means may be set to a ground potential. The permanent magnets of the auxiliary magnetic field generating means may be arranged such that the tip side protrudes from the opposing surface of the target.

  Further, the auxiliary magnetic field generating means may be arranged along the periphery so as to surround the pair of targets.

  According to such a configuration, the auxiliary magnetic field generation means is arranged along the periphery of the pair of targets, so that the auxiliary magnetic field space is formed in a cylindrical shape along the outer periphery of the inter-target magnetic field space. That is, the auxiliary magnetic field space is formed so as to wrap the entire outer periphery of the columnar inter-target magnetic field space formed so as to connect the sputtering surfaces of the pair of targets.

  Therefore, the confinement magnetic field space has a width from the TT line, that is, a distance from the TT line to the end thereof, which is larger than the inter-target magnetic field space by the auxiliary magnetic field space over the entire circumference. Therefore, the confinement effect of plasma and the confinement effect of charged particles such as secondary electrons are improved.

  As a result, without reducing the distance between the centers of the pair of targets, the influence of plasma on the substrate to be deposited and the influence of secondary electrons flying from the sputtering surface can be extremely reduced. Damage film formation is possible.

  Further, the auxiliary magnetic field generating means may be arranged so that the magnetic field intensity at the peripheral edge of the target increases with increasing distance from the center of the target.

  According to this configuration, it is possible to obtain a magnetic field distribution in which the magnetic field intensity at the target peripheral portion increases as the distance from the TT line increases.

  That is, in the conventional opposed target type sputtering apparatus in which the magnet is arranged only on the back side of each backing plate, when the input power to be applied to the cathode is increased, the plasma between the targets is concentrated in the central part, Along with this, the erosion of the target also increases at the center. This phenomenon appears more conspicuously than when the target is a non-magnetic material since the target is a yoke when the target is a magnetic material. However, according to the above configuration, the confined magnetic field space is formed so as to have a magnetic field distribution that increases the magnetic field strength on the outer peripheral side, so even if the target is a magnetic body, By increasing the input power, the concentration of plasma at the central portion between the targets can be alleviated, and the size of the erosion and the central portion are not particularly increased. Therefore, even if the target is made of a magnetic material, it is possible to suppress a decrease in the utilization efficiency of the target, and the film thickness distribution of the thin film formed on the substrate becomes uniform (uniformized).

Further, facing target sputtering method according to the present invention is to oppose each other at a distance, to face the substrate to be film-forming target disposed on one of the lateral position, arranged to be inclined surfaces facing each other A target magnetic field space in which a magnetic field line is directed from one target to the other target is generated between a pair of targets to be sputtered, and sputtering is performed on the film formation surface on the substrate with the sputtered particles. in target sputtering method, the pair of the pair comprises auxiliary magnetic field generating means a cylindrical permanent magnet disposed along its periphery so as to surround the respective targets, along said target between magnetic field space,且previous serial auxiliary magnetic field space is generated so as to have a field lines toward the same direction as the direction of magnetic field lines at the target inter-magnetic field space, the teeth In addition, each permanent magnet of the auxiliary magnetic field generating means is formed such that the bottom wall, which is the peripheral wall on the substrate side, is thicker than the top wall, which is the peripheral wall on the opposite side, and the inter-target magnetic field space and the substrate so as to generate said auxiliary magnetic field space between the position so as to block the of the bottom wall is characterized Rukoto is arranged to be positioned between the target and the substrate.

  According to such a configuration, an inter-target magnetic field space is generated between a pair of targets, and the inter-target magnetic field is located at a position along the inter-target magnetic field space and at least between the target and the substrate. Since the auxiliary magnetic field space having the magnetic field lines directed in the same direction as the direction of the magnetic field lines in the space is generated and sputtered, the width of the confined magnetic field space from the TT line in the substrate direction is more assisted than the inter-target magnetic field space. Increases by the amount of magnetic field space. Therefore, similarly to the above, it is possible to effectively prevent the plasma and secondary electrons from jumping out from the confined magnetic field space.

  Therefore, it is possible to prevent plasma, secondary electrons and the like from reaching the substrate without shortening the distance between the centers of the pair of targets, and low-temperature and low-damage film formation is possible.

  Further, the auxiliary magnetic field space may be formed in a cylindrical shape so as to surround the periphery of the inter-target magnetic field space.

  According to such a configuration, since the inter-target magnetic field space is surrounded by the auxiliary magnetic field space formed in a cylindrical shape over the entire circumference, the confined magnetic field space has a width from the TT line, that is, T- The distance from the T-line to the end thereof is larger than the inter-target magnetic field space by the auxiliary magnetic field space over the entire circumference, and the confinement effect of plasma and the confinement effect of charged particles such as secondary electrons are improved.

  As a result, without reducing the distance between the centers of the pair of targets, the influence of plasma on the substrate to be deposited and the influence of secondary electrons flying from the sputtering surface can be extremely reduced. Damage film formation is possible.

  As described above, according to the present invention, in the opposed target sputtering apparatus and sputtering method, between the targets of charged particles such as plasma and secondary electrons formed between the targets without shortening the distance between the centers of the pair of targets. By increasing the confinement effect, it is possible to provide a sputtering apparatus and a sputtering method capable of low-temperature and low-damage film formation.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

  As shown in FIG. 1, a sputtering apparatus 1 includes a target holder 11a, 11b having a pair of targets 10a, 10b disposed at the tip, a vacuum vessel (chamber) 2, a power supply 3 for supplying sputtering power, a substrate holder 4, and an exhaust device. 5. A gas supply device 6 is provided.

  In the present embodiment, each of the pair of targets 10a and 10b is made of indium tin oxide (ITO). The targets 10a and 10b are each formed into a rectangular plate-like body having a size of 125 mm in width, 300 mm in length, and 5 mm in thickness. The targets 10a and 10b are arranged to face each other in the vacuum vessel 2, and the opposed surfaces (surfaces to be sputtered) 10a ′ and 10b ′ have a predetermined interval (here, the centers Ta and 10a ′ and 10b ′ of the facing surfaces 10a ′ and 10b ′). They are arranged with a distance between Tb and d = 160 mm in the figure. The target holders 11a and 11b support and fix the targets 10a and 10b via the backing plates 12a and 12b, respectively. The target holders 11a and 11b are interposed via an insulating plate (not shown) so that the tip side is positioned inside the vacuum vessel 2. The vacuum vessel 2 is attached.

  The pair of targets 10a and 10b is placed on the film-forming surface B ′ of the substrate B in which both opposing surfaces 10a ′ and 10b ′ are fixed by the substrate holder 4 in the vacuum vessel 2 by the target holders 11a and 11b. It is arranged so as to be inclined. Specifically, the angle A formed by the opposing surfaces 10a ′ and 10b ′, more specifically, the angle A formed by the surfaces extending in the direction along the opposing surfaces 10a ′ and 10b ′ is greater than 0 ° and 90 °. ° or less. The angle A is more preferably greater than 0 ° and not greater than 30 °, and in this embodiment is 5 °. In this way, the targets 10a 'and 10b' in which the opposing surfaces 10a 'and 10b' are substantially V-shaped are referred to as "V-type opposing targets".

  Inter-target magnetic field generating means 20a and 20b are disposed on the outer surfaces of the backing plates 12a and 12b that fix the targets 10a and 10b (surfaces opposite to the surfaces on which the targets 10a and 10b are fixed). . The inter-target magnetic field generating means is means for generating (forming) a magnetic field space (inter-target magnetic field space) between the targets 10a and 10b, and in the present embodiment, is configured by a permanent magnet.

  The inter-target magnetic field generating means (permanent magnets) 20a and 20b are made of a ferromagnetic material such as a neodymium (for example, neodymium, iron, or boron) magnet or an alnico magnet. In this embodiment, the neodymium magnet is used. It consists of As shown in FIG. 2, the inter-target magnetic field generating means 20a, 20b is formed in a rectangular tube shape. More specifically, the inter-target magnetic field generating means 20a, 20b is formed in a rectangular frame shape when viewed from the front, and the thickness of the peripheral wall along the front-rear direction is constant (see FIGS. 2B and 2C). It is formed in a square tube shape. And the thickness of the surrounding wall which comprises the inter-target magnetic field generation | occurrence | production means 20a, 20b is formed so that the top wall 21 may be the thinnest, the side walls 22 and 22 are next thin, and the bottom wall 23 may be the thickest.

  The thickness of the peripheral wall is constant in the magnetic field strength in a virtual plane orthogonal to the line connecting the centers Ta and Tb of the targets 10a and 10b (hereinafter sometimes simply referred to as “T-T line”) and the intermediate point thereof. The thickness is set so that Accordingly, the difference in thickness varies depending on the angle A formed by the opposing surfaces 10a 'and 10b'. Therefore, when the angle A formed becomes large, the thickness of the side walls 22 and 22 may be set so as to gradually increase from the top wall 21 toward the bottom wall 23 (dotted line in FIG. 2A). reference).

  The inter-target magnetic field generating means 20a and 20b are arranged so that the thickest bottom wall 23 is on the substrate holder 4 side and the thinnest top wall 21 is on the opposite side of the substrate holder 4 on the outer surface of the backing plates 12a and 12b. Has been placed. Further, the one inter-target magnetic field generating means 20a is arranged so that the N pole faces the outer surface of the one target 10a in order to generate a magnetic field in a direction perpendicular to the facing surface 10a ′. The other inter-target magnetic field generating means 20b is arranged so that the south pole faces the outer surface of the other target 10b in order to generate a magnetic field in a direction perpendicular to the opposing surface 10b ′. Yes. In this manner, an inter-target magnetic field space in which magnetic lines of force are directed from the facing surface 10a 'to the facing surface 10b' is formed between the facing surfaces 10a 'and 10b' of the targets 10a and 10b.

  The auxiliary magnetic field generating means 30a and 30b are formed of permanent magnets similarly to the inter-target magnetic field generating means 20a and 20b, and as shown in FIG. (Possible) is formed in a rectangular tube shape. Similarly to the inter-target magnetic field generating means 20a, 20b, the auxiliary magnetic field generating means 30a, 30b also has the thinnest peripheral wall constituting the auxiliary magnetic field generating means 30a, 30b, and the thinnest side walls 32, 32. The bottom wall 33 is formed to be the thickest. Similarly to the inter-target magnetic field generating means 20a, 20b, when the angle A formed by the opposing surfaces 10a ′, 10b ′ is large, the thickness of the side walls 32, 32 is from the top wall 31 toward the bottom wall 33. In some cases, the thickness is gradually increased (see the dotted line in FIG. 3A).

  The auxiliary magnetic field generating means 30a and 30b are arranged so that the magnetic poles are externally fitted to the outer circumferences of the front ends of the target holders 11a and 11b with the same orientation as the inter-target magnetic field generating means 20a and 20b (FIG. )reference). By arranging in this way, there is an auxiliary magnetic field space along the inter-target magnetic field space formed by the inter-target magnetic field generating means 20a, 20b and in which the direction of the magnetic field lines is the same as the magnetic field lines in the inter-target magnetic field space. It is formed.

  The power supply 3 for supplying sputtering power is a power supply capable of applying a constant DC power, and supplies the sputtering power using the vacuum vessel 2 at the ground potential (earth potential) as an anode and the targets 10a and 10b as cathodes. .

  The substrate holder 4 supports the substrate B and is arranged so that the film formation surface B ′ of the substrate B faces the space K formed between the opposing surfaces 10 a ′ and 10 b ′ by the targets 10 a and 10 b. In this embodiment, the shortest distance between the straight line (TT line) connecting the centers Ta and Tb of the opposing surfaces 10a ′ and 10b ′ of the targets 10a and 10b and the film formation surface B ′ is shown in FIG. e = 175 mm.

  The vacuum vessel 2 is connected to an exhaust device 5 and a discharge gas supply device 6. The gas supply device 6 includes inert gas introduction pipes 6 ′ and 6 ′ for supplying an inert gas (in this embodiment, argon (Ar) gas) disposed in the vicinity of the targets 10a and 10b. It is out.

  The sputtering apparatus according to the present embodiment has the above configuration, and next, the operation of the sputtering apparatus will be described.

  In forming a thin film on the deposition surface B ′ of the substrate B, first, the inside of the vacuum container (chamber) 2 is evacuated by the evacuation device 5. Thereafter, argon gas (Ar) is introduced from the inert gas introduction pipes 6 ′ and 6 ′ by the gas supply device 6 to obtain a predetermined sputtering operation pressure (here, 0.13 Pa).

  Then, sputtering power is supplied between the substrate holder 4 and the targets 10a and 10b by the power supply 3 for supplying sputtering power. A magnetic field is formed in the space K formed between the opposing surfaces 10a 'and 10b' of the targets 10a and 10b by the inter-target magnetic field generating means 20a and 20b and the auxiliary magnetic field generating means 30a and 30b.

  Then, in the space K, the facing surfaces 10a ′ and 10b ′ of the targets 10a and 10b are sputtered to form plasma in which sputtered particles, secondary electrons, argon gas ions, etc. are scattered, and the plasma is confined in the space K. It is done.

  In this way, the sputtered particles that have jumped out of the targets 10a and 10b are attached to the substrate B disposed in the space K so that the film formation surface B 'faces, thereby forming a thin film.

  At that time, the auxiliary magnetic field generating means 30a and 30a are arranged so that the magnetic poles are fitted on the outer circumferences of the front ends of the target holders 11a and 11b in the same direction as the inter-target magnetic field generating means 20a and 20b. An auxiliary magnetic field space is formed along the magnetic field space between the targets formed by the magnetic field generating means 20a and 20b, and the direction of the magnetic force lines is the same as the magnetic force lines in the magnetic field space between the targets.

  Therefore, a space having a high magnetic flux density formed on the substrate side from a line (TT line) connecting the centers Ta and Tb of the opposing sputtering surfaces (opposing surfaces) 10a ′ and 10b ′ of the pair of targets 10a and 10b. The distance to the end of the (confined magnetic field space described later) (width of the confined magnetic field space) is increased, and the magnetic field space (hereinafter referred to as the magnetic field space formed by the inter-target magnetic field space and the auxiliary magnetic field space formed outside thereof) It is simply referred to as “confinement magnetic field space”). As described above, since the plasma is confined in the confined magnetic field space, the influence of the plasma on the substrate can be reduced.

  In addition, charged particles such as secondary electrons that jump out from the inter-target magnetic field space to the substrate side will jump out because the width of the confined magnetic field space is larger than the inter-target magnetic field space by the auxiliary magnetic field space. The moving distance of the charged particles in the magnetic field space (confined magnetic field space) increases. For this reason, the effect of confining charged particles in the confined magnetic field space is increased. In other words, the ejection of charged particles from the confined magnetic field space toward the substrate B is reduced.

  Further, since the auxiliary magnetic field generating means 30a and 30b are arranged along the periphery so as to surround the pair of targets 10a and 10b, between the sputter surfaces 10a ′ and 10b ′ of the pair of targets 10a and 10b. The auxiliary magnetic field space is formed so as to wrap the entire outer periphery of the columnar inter-target magnetic field space formed so as to connect the two.

  Therefore, since the width of the confined magnetic field space from the TT line, that is, the distance from the TT line to the end thereof, is larger than the inter-target magnetic field space by the auxiliary magnetic field space over the entire circumference, the plasma confinement The effect and the confinement effect of charged particles such as secondary electrons are improved.

  As a result, the substrate B, which is the film formation target, can extremely reduce the influence of plasma and the influence of secondary electrons flying from the sputter surfaces 10a and 10b, and enables low temperature and low damage film formation.

  Further, since the auxiliary magnetic field generating means 30a and 30b are arranged (set) so that the magnetic field strength at the peripheral portions of the targets 10a and 10b increases with distance from the central portion of the target, each peripheral edge of the targets 10a and 10b. It is possible to obtain a magnetic field distribution in which the magnetic field strength of the part increases as the distance from the TT line increases.

  Therefore, even if the targets 10a and 10b are magnetic materials, the concentration of plasma at the central portion between the targets 10a and 10b can be reduced by increasing the input power to the cathode, and the erosion is particularly large in the central portion. It will never be. Therefore, even if the targets 10a and 10b are made of a magnetic material, it is possible to suppress a decrease in the utilization efficiency of the target, and the film thickness distribution of the thin film formed on the substrate B (deposition surface B ′) is also uniform. (It becomes uniform). In the present embodiment, the magnetic field strength at the center between the auxiliary magnetic field generating means 30a and 30b of the auxiliary magnetic field generated by the auxiliary magnetic field generating means 30a and 30b is 250 Gauss or more.

  Further, the auxiliary magnetic field generating means 30a and 30b are arranged such that the thick bottom walls 33 and 33 are on the side where the distance between the opposing surfaces of the pair of targets 10a and 10b is increased (substrate B side). Therefore, the magnetic field strength in the vicinity of the auxiliary magnetic field generating means 30a and 30b increases as the distance between the opposing surfaces of the pair of targets 10a and 10b increases.

  If the magnetic field strengths in the vicinity of the auxiliary magnetic field generating means 30a and 30b arranged along the peripheral edges of the pair of targets 10a and 10b are all the same, the surfaces of the pair of targets 10a and 10b facing each other ( (Sputtering surfaces) 10a 'and 10b' are arranged so as to be inclined so as to face the film-forming surface B 'of the substrate B, so that the magnetic field intensity at the intermediate point from one target 10a to the other target 10b is As the distance between the opposing surfaces increases, the distance decreases. Therefore, plasma, secondary electrons, etc. will jump out from the portion where the magnetic field strength is weak (on the substrate B side).

  However, according to the above configuration, the magnetic field strength at the intermediate point is set so that the magnetic field strength in the vicinity of the auxiliary magnetic field generating means 30a and 30b increases as the distance between the opposing surfaces increases. A constant magnetic field strength can always be obtained.

  Therefore, even in the case of a V-type counter target, it is possible to suppress the plasma and secondary electrons from jumping out from the location where the distance between the counter surfaces 10a ′ and 10b ′ increases, and confine the plasma and secondary electrons between the targets. The effect is good, and low temperature and low damage film formation is possible.

  Further, the magnetic field strength in the vicinity of the inter-target magnetic field generating means 20a, 20b is also set to increase as the distance between the opposing surfaces of the pair of targets increases.

  According to such a configuration, similarly to the auxiliary magnetic field generation means 30a and 30b, the magnetic field strength in the vicinity of the inter-target magnetic field generation means 20a and 20b is set stronger as the distance between the opposing surfaces increases. The magnetic field strength at the intermediate point from the target 10a to the other target 10b can always obtain a constant magnetic field strength.

  Accordingly, the distance between the sputtering surfaces 10a ′ and 10b ′ on the substrate side is increased by arranging the opposing surfaces to be inclined, and plasma, secondary electrons, etc. are obtained from the point where the distance between the targets 10a and 10b is increased. Can be prevented from jumping out.

  Specifically, in the inter-target magnetic field generating means 20a, 20b, the thick bottom walls 23, 23 are on the side (substrate B side) where the distance between the opposing surfaces of the pair of targets 10a, 10b increases. Placed.

  The auxiliary magnetic field generating means 30a, 30b may be set to any one of earth potential, minus potential, plus potential, and floating (electrically insulated state), or earth potential and minus potential, or earth potential. And the positive potential may be set to alternately switch in time.

  By setting the potential of the auxiliary magnetic field generating means 30a, 30b to any of the above, the discharge voltage is lower than that of the V-type opposed target sputtering apparatus (conventional sputtering apparatus) that does not include the auxiliary magnetic field generating means 30a, 30b. Voltage can be realized. This is because the target 10a, 10b is made of ITO, the size is 125 × 300 × 5 mm, the TT distance is 160 mm, the application method is DC (constant current), the parameters are magnetic field arrangement, and auxiliary magnetic field generating means This is also supported by FIG. 4 showing the results of measuring the discharge characteristics when the voltage is set to. That is, when the potential of the auxiliary magnetic field generating means 30a, 30b is the ground potential (see (1) and (2) in FIG. 4), when the sputtering pressure is 0.13 Pa, the current is 2V and the current is 3V. The discharge voltage decreases by about 30V at a current of 4A. Further, when the potentials of the auxiliary magnetic field generating means 30a and 30b are negative (see (1) and (3) in FIG. 4), the discharge voltage is higher than that of the ground potential. The discharge voltage has decreased. Further, when the potentials of the auxiliary magnetic field generating means 30a and 30b are positive potentials (see (1) and (4) in FIG. 4), the discharge voltage is further reduced as compared with the case of the ground potential, and the current 2A is about 70V. The discharge voltage is lower than that of the conventional sputtering apparatus by about 65V at the current 3A and about 60V at the current 4A. By reducing the discharge voltage as described above, the kinetic energy of the sputtered particles can be reduced, and the film damage during film formation can be reduced.

  Hereinafter, various measurement results when using the sputtering apparatus 1 according to the present embodiment and changing various conditions to form an ITO film on the substrate are shown.

  First, a V-type counter target (A = 5 °), the target material is ITO, the size is 125 × 300 × 5 mm, the T-T distance is 160 mm, the internal magnetic field magnet (the generation of the magnetic field between the targets) Means) distance (MM) is 190 mm, external magnetic field magnet (auxiliary magnetic field generating means) distance (MM) is 139 mm, magnetic field arrangement is internal magnetic field (target magnetic field) t10, external magnetic field (auxiliary magnetic field) ) Is t12, and the magnetic field distribution at the center (center) between the two targets measured when the parameter is the magnetic field arrangement and strength is shown in FIG. 5 (magnetic field distribution along the short side direction of the target) and FIG. Magnetic field distribution along the side direction), FIG. 7 (magnetic field distribution viewed from the long side of the target), and FIG. 8 (magnetic field distribution viewed from the short side of the target).

  From FIG. 5 to FIG. 8, it can be seen that the magnetic field distribution between the targets increases in magnetic field strength from the center to the outside.

Second, the V-type counter target (A = 5 °), the target material is ITO, the size is 125 × 300 × 5 mm, the magnetic field arrangement is the internal magnetic field (inter-target magnetic field) t10 and the external magnetic field (auxiliary magnetic field) Is t12, the application method is DC (constant current) or RF is superimposed on DC, the TT distance (d) is 160 mm, and the parameter is RF power. FIG. 9 shows the results obtained by measuring discharge characteristics when the sputtering pressure is 0.13 Pa, Ar is 50 sccm, O ₂ is 0 sccm, and the shutter is open.

  From FIG. 9, the discharge characteristic in the sputtering apparatus according to the present invention with an external magnetic field is a low potential discharge, compared to the discharge characteristic in the conventional sputtering apparatus without an external magnetic field (auxiliary magnetic field) (see FIG. 9 (1)). I understand that. Therefore, it can be seen that in a sputtering apparatus equipped with an external magnetic field, the kinetic energy of sputtered particles can be reduced to reduce film damage during film formation.

  It can also be seen that by applying RF to DC (constant current) as the application method, the discharge characteristics rise smoothly from 0 V, and low voltage discharge is possible.

  Third, as a conventional sputtering apparatus, a V-type counter target, the target material is ITO, the internal magnetic field is t10, the application method is DC (1.74 kw, 344 V, 5 A), and the discharge condition is a sputtering pressure of 0. Sputtering apparatus with 13 Pa, Ar50 sccm and auxiliary magnetic field generating means, V-type counter target, target material is ITO, internal magnetic field is t10, external magnetic field is t12, application method is DC (1.58kw, 394V, 4A) FIG. 10 shows a photograph of the plasma confinement between the targets when the discharge is performed under the sputtering conditions of 0.13 Pa and Ar 50 sccm. 10A shows a photograph of a conventional sputtering apparatus, and FIG. 10B shows a photograph of a sputtering apparatus provided with auxiliary magnetic field generating means.

  From FIG. 10, it can be seen that the confinement state of the plasma (the bright (white) part in the center) is improved in the sputtering apparatus provided with the auxiliary magnetic field generating means as compared with the conventional sputtering apparatus.

  As described above, the auxiliary magnetic field generating means for generating the auxiliary magnetic field (external magnetic field) space at a position along the inter-target magnetic field (internal magnetic field) space is arranged around the pair of targets, thereby narrowing the target interval. Without increasing the magnetic field strength at the center of the target, and the magnetic field strength increases toward the peripheral side (outward in the radial direction with TT as the axis) from the center along the TT line. The following magnetic field distribution can be obtained. As a result, the confinement effect of plasma between a pair of targets and the confinement effect of charged particles such as secondary electrons are improved, and low temperature and low damage film formation can be performed without shortening the distance between the centers of the pair of targets. It becomes possible.

  In addition, an ITO film is produced by a V-type counter target sputtering apparatus (Examples 2 to 4) provided with auxiliary magnetic field generating means (external magnetic field magnet) according to the present invention, and no conventional auxiliary magnetic field generating means is provided. The film characteristics and the substrate temperature were compared with those of the ITO film produced by the V-type opposed target sputtering apparatus (Comparative Examples 1 and 2). Table 1 shows the measurement results and measurement conditions obtained as a result. The revolution state under the film forming conditions in Table 1 indicates the state of the substrate moving along a revolution trajectory (see FIG. 14) described later.

As shown in Table 1, when the sputtering apparatus for the V-type counter target according to the present invention is compared with the sputtering apparatus for the conventional V-type counter target, the film formation time is 30 minutes (Example 3 and Comparative Example 2). When the film formation time was 45 minutes (Example 2 and Comparative Example 1), the temperature was lowered by about 10 ° C. The best value of the specific resistance, which is the main characteristic of the ITO film, is 4.5 × 10 ⁻⁴ Ω · cm under the conditions of Example 4, whereas the best value in the conventional V-type facing target sputtering apparatus. Since the value was 5.0 × 10 ⁻⁴ Ω · cm, a characteristic improvement of about 10% was observed.

  As described above, the sputtering apparatus for a V-type counter target (with an external magnetic field) according to the present invention can form a film at a low temperature and with low damage compared to a conventional sputtering apparatus for a V-type counter target (without an external magnetic field). It was confirmed that

  It should be noted that the sputtering apparatus and sputtering method of the present invention are not limited to the above-described embodiment, and it is needless to say that various changes can be made without departing from the gist of the present invention.

  In the present embodiment, as shown in FIG. 3, the top wall 31 is the thinnest as auxiliary magnetic field generating means for obtaining a magnetic field distribution in which the magnetic field strength at the target peripheral portion increases as the distance from the TT line increases. Next, the side walls 32 and 32 are formed in a rectangular tube shape so that the bottom wall 33 is the thickest, the magnetic poles are oriented in the same direction as the inter-target magnetic field generating means 20a and 20b, and the bottom wall 33 is on the substrate B side. The outer ends of the target holders 11a and 11b are arranged so as to be fitted on the outer periphery. However, the arrangement of the auxiliary magnetic field generating means is not necessarily limited to the above arrangement. For example, as in the sputtering apparatus 1 ′ shown in FIG. 11, the rectangular auxiliary magnetic field generating means 30a ′ and 30b ′ are the targets. The inter-target magnetic field generating means 20a, 20b inside the holders 11a, 11b may be fitted on the outside so that the thickest bottom wall 33 ′ is on the substrate B side. In addition, as in the sputtering apparatus 1 ″ shown in FIG. 12, the rectangular cylindrical auxiliary magnetic field generating means 30a ″ and 30b ″ do not have to follow the outer circumferences of the target holders 11a and 11b, and the film formation on the substrate B is performed. You may install so that it may become parallel to surface B '. In this case, the distance M′−M ′ between the auxiliary magnetic field generating means 30 a ″ and 30 b ″ may be the same as or narrower than the center distance d between the targets 10 a and 10 b. When it is narrow, the film formation area of the substrate B is small, and therefore the substrate holder 4 is configured to be sputtered while being transported along the film formation surface B ′ (in the direction of the arrow α or α ′). preferable.

  Further, the auxiliary magnetic field generating means is not necessarily limited to the rectangular tube shape, and the thinnest top wall 31 ′, the next thin side walls 32 ′ and 32 ′, and the thickest bottom wall 33 as shown in FIG. 'May be disposed along the outer periphery of a rectangular opening H formed in the center of the front view, and the corners may be connected to each other. Even if it is such a shape, the target wall 11 ′, 11b tilted in a V shape is externally fitted so that the bottom wall 33 ′ is on the substrate B side. Even if the distance between the targets on the B side is different, the magnetic field strength on the virtual plane orthogonal in the middle of the TT line is the same.

  Further, the auxiliary magnetic field generating means is not necessarily limited to the rectangular tube shape, and may be a cylindrical shape, a polygonal cylindrical shape, or the like according to the shape of the target. Moreover, it is not necessary to have a cylindrical shape along the shape of the target, and may be a shape different from the contour shape of the target as long as the auxiliary magnetic field can be formed so as to surround the target.

  In this embodiment, the power applied to the targets 10a and 10b is a DC constant current. However, the present invention is not limited to this, and as shown in the first embodiment, only an RF power source may be used. RF may be superimposed on.

  Moreover, in this embodiment, although the board | substrate B is being fixed, it does not need to be limited to this. That is, when the film formation area of the film formation surface B ′ of the substrate B is larger than the film forming area range of the sputtering apparatus, or in order to make the film thickness distribution of the formed film uniform, FIG. As shown, the film formation surface B ′ may be arranged so as to move (arrow β) along the TT selection, and as shown in FIG. 14B, the film formation surface B ′. Is centered on the revolution center c set at a predetermined position on the center line C orthogonal to the center of the TT line, and the film formation surface B ′ is parallel to the TT line. It may be arranged so as to move (arrow γ) along a revolution trajectory such that the distance between the center of the film surface B ′ and the middle of the TT line is the shortest distance e. Further, the movement direction (arrows β and γ) of the film formation surface B ′ may move in one direction, or may reciprocate (or swing).

The schematic block diagram of the sputtering device which concerns on this embodiment is shown. (A) of the inter-target magnetic field generating means in the sputtering apparatus according to the embodiment shows a front view, (b) shows an AA cross-sectional view, and (c) shows a BB cross-sectional view. (A) of the auxiliary magnetic field generating means in the sputtering apparatus according to the embodiment shows a front view, and (b) shows a partially enlarged view of the attached state. The discharge characteristic figure measured by changing the electric potential of an auxiliary magnetic field generation means with a V type opposed target type sputtering device provided with an auxiliary magnetic field generation means is shown. The magnetic field distribution figure (direction along a short side) which measured the change of the magnetic field by the presence or absence of an auxiliary magnetic field generation means with a V type opposed target type sputtering device is shown. The magnetic field distribution figure (direction along a long side) which measured the change of the magnetic field by the presence or absence of an auxiliary magnetic field generation device with a V type opposed target type sputtering device is shown. The magnetic field distribution seen from the long side of the target in the center (center) between the targets of the V-type counter target type sputtering apparatus provided with the auxiliary magnetic field generating means is shown. The magnetic field distribution seen from the short side of the target in the center (center) between the targets of the V-type counter target type sputtering apparatus provided with the auxiliary magnetic field generating means is shown. The discharge characteristic figure measured by changing RF electric power superimposed on DC electric power applied between a substrate holder and a target of a V type counter target type sputtering device provided with auxiliary magnetic field generating means is shown. (A) shows the confinement state of plasma between targets in a conventional V-type opposed target sputtering apparatus that does not have auxiliary magnetic field generation means, and (B) shows V-type opposed target sputtering that has auxiliary magnetic field generation means. The plasma confinement state between targets in the apparatus is shown. The schematic block diagram of the sputtering device which concerns on other embodiment provided with the auxiliary magnetic field generation | occurrence | production means in the target holder is shown. The schematic block diagram of the sputtering device which concerns on other embodiment provided with the auxiliary magnetic field generation means arrange | positioned in the direction along the film-forming surface of a board | substrate is shown. The front view of the auxiliary magnetic field generation means in the sputtering device which concerns on other embodiment is shown. (A) shows a schematic configuration diagram of a sputtering apparatus in which a film formation surface moves along a TT line, and (B) shows a schematic configuration of a sputtering apparatus in which the film formation surface moves along a revolution orbit. The figure is shown. The schematic block diagram of the conventional facing target type | mold sputtering device is shown.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Sputtering device, 2 ... Vacuum container (chamber), 3 ... Power supply for sputter power supply, 4 ... Substrate holder, 5 ... Exhaust device, 6 ... Gas supply device, 6 '... Inert gas introduction pipe, 10a, 10b ... Target, 10a ', 10b' ... Sputtering surface (opposite surface), 11a, 11b ... Target holder, 12a, 12b ... Backing plate, 20a, 20b ... Inter-target magnetic field generating means (permanent magnet), 21, 31, 31 '... Top wall, 22, 32, 32 '... side wall, 23, 33, 33' ... bottom wall, 30a, 30b ... auxiliary magnetic field generating means (permanent magnet), B ... substrate, B '... film formation surface, d ... target Center distance, Ta, Tb ... center of target

Claims (4)

Between a pair of targets arranged so as to face each other with a spacing, the target inter-field generating means for generating a target inter magnetic field space is provided,
The pair of targets are respectively disposed with inclined surfaces facing each other so as to face a film formation surface of a substrate to be formed, which is disposed at one side position between the pair of targets .
The inter-target magnetic field generating means is an opposed target sputtering apparatus in which the polarity is set so that the magnetic field lines in the inter-target magnetic field space are directed from one target to the other target.
An auxiliary magnetic field generating means for generating an auxiliary magnetic field space at a position along the inter-target magnetic field space;
The auxiliary magnetic field generating means includes a pair of cylindrical permanent magnets arranged along the periphery of each of the pair of targets so that the magnetic field lines in the auxiliary magnetic field space are the same as the magnetic field lines in the inter-target magnetic field generating space. The polarity is set to go in the direction ,
Each of the permanent magnets of the auxiliary magnetic field generating means is formed such that a bottom wall that is a peripheral wall on the substrate side is thicker than a top wall that is a peripheral wall on the opposite side, and the inter-target magnetic field space and the substrate An opposed target sputtering apparatus , wherein the bottom wall is disposed between the target and the substrate so as to generate the auxiliary magnetic field space at a position that interrupts the gap. 2. The opposed target sputtering apparatus according to claim 1, wherein each permanent magnet of the auxiliary magnetic field generating means is set to a ground potential. 3. The opposed target sputtering apparatus according to claim 1, wherein each of the permanent magnets of the auxiliary magnetic field generating unit is disposed such that a tip side protrudes from an opposed surface of the target. Together facing each other with a spacing, to face the substrate to be film-forming target disposed on one of the lateral position, the other from one of the target between a pair of targets are disposed to be inclined surfaces facing each other In the facing target type sputtering method in which the magnetic field space between the targets is generated so that the magnetic lines of force are directed toward the target, and sputtering is performed, and the sputtered sputtered particles form a film on the film formation surface on the substrate.
Said pair of auxiliary magnetic field generating means each comprise a pair of cylindrical permanent magnets disposed along its periphery so as to surround the targets, along said target between magnetic field space, in the magnetic field space between且previous Symbol Target Auxiliary magnetic field space having magnetic field lines that run in the same direction as the magnetic field lines is generated ,
Each of the permanent magnets of the auxiliary magnetic field generating means is formed such that a bottom wall that is a peripheral wall on the substrate side is thicker than a top wall that is a peripheral wall on the opposite side, and the inter-target magnetic field space and the substrate in order to generate the auxiliary magnetic field space in a position so as to block between the bottom wall is arranged to be positioned between the target and the substrate facing target sputtering method comprising Rukoto.

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