JP5725460B2 - Sputtering equipment - Google Patents

Description

  The present invention relates to a sputtering apparatus.

  When a thin film is formed on a substrate, a magnetron sputtering method is often used because of advantages such as a high deposition rate. In the magnetron sputtering method, a magnet member composed of a plurality of magnets whose polarities are alternately changed is installed behind the target, and a magnetic flux is formed in front of the target by this magnet member to capture electrons. The electron density is increased, the collision probability between these electrons and the gas introduced into the vacuum chamber is increased, and the plasma density is increased to perform sputtering.

  By the way, in recent years, as the substrate becomes larger, the magnetron sputtering apparatus is also enlarged. For this reason, a sputtering apparatus that can form a film on a large-area substrate by arranging a plurality of targets in parallel is known (see, for example, Patent Document 1).

JP 2008-25031 A (see FIG. 2 etc.)

  However, in the sputtering apparatus described in Patent Document 1, sputtered particles ejected from the target during sputtering may not adhere to the substrate and may adhere to a region where the target is not eroded, so-called non-erosion region. The adhered sputtered particles are easily peeled off from the target by arc discharge or the like. If the peeled sputtered particles adhere to the substrate, the adhesiveness is low, so that there is a problem that the film is liable to peel off at this portion and the film forming characteristics are deteriorated.

  Accordingly, an object of the present invention is to solve the above-described problems of the prior art, and an object of the present invention is to provide a sputtering apparatus that suppresses adhesion of sputtered particles to a non-erosion region and has high film forming characteristics.

A sputtering apparatus according to the present invention includes a vacuum chamber, a power source for applying a voltage to a target provided at a position facing a substrate installed in the vacuum chamber, and a gas introduction means for introducing a gas into the vacuum chamber. A plurality of the targets are provided side by side with a predetermined interval, and an end portion of the target is a shield member that covers an upper surface of the end portion and has a ground potential. The shield member covers the upper surface of the opposite end portions of the adjacent targets, and the width of the upper portion of the shield member covering the upper surface of the end portion of the target is When the shield member is not provided, the width is the same as the width of the upper portion of the non-erosion region formed on the target. Since the sputtering apparatus of the present invention has the shield member, the non-erosion region formed at the end of the target can be covered, and adhesion of sputtered particles to the non-erosion region can be suppressed.

  Here, it is preferable that a plurality of the targets are arranged in parallel at a predetermined interval, and the shield member covers the upper surfaces of the end portions of the adjacent targets facing each other. By having a shield member that covers the upper surfaces of the ends of the adjacent targets facing each other, most of the non-erosion region formed at the end of the target can be covered, and adhesion of sputtered particles to the non-erosion region Can be further suppressed.

  In addition, it is preferable that a taper is provided in an area of the adjacent target covered with the shield member. By providing a taper, it is difficult to form a non-erosion region on the target, and even if a non-erosion region is formed, since the taper is formed, compared to the case where no taper is formed. Therefore, spatter particles are difficult to adhere. Moreover, since the taper is formed, it is difficult for the target and the shield member to be electrically connected.

  Moreover, it is preferable that a shield member is further provided so as to cover the upper surfaces of the end portions of the targets at both ends in the direction in which the targets are juxtaposed. By further covering this portion, the non-erosion region can be further covered, and adhesion of sputtered particles to the non-erosion region can be further suppressed.

  According to the sputtering apparatus of the present invention, it is possible to suppress the adhesion of sputtered particles to the non-erosion region, thereby achieving an excellent effect that the film forming characteristics can be improved.

1 is a schematic cross-sectional view of a sputtering apparatus according to Embodiment 1. FIG. 3 is a schematic cross-sectional perspective view of the vicinity of a target in the sputtering apparatus according to Embodiment 1. FIG. FIG. 3 is a schematic top view showing a part of a target and a shield member according to the first embodiment. It is typical sectional drawing of the target vicinity in the sputtering device concerning Embodiment 2. FIG. It is a graph which shows the measurement result concerning a reference example and a comparative example. It is typical sectional drawing of the target vicinity in the sputtering device concerning Embodiment 3. FIG.

(Embodiment 1)
The sputtering apparatus of the present invention will be described below.

  The sputtering apparatus 1 includes a vacuum chamber 11. The substrate S is transported to the sputtering apparatus 1, and the substrate S is held on the ceiling surface side of the vacuum chamber 11 by a substrate holding unit (not shown) with the film formation surface facing the floor surface side.

A gas introducing means 12 is provided on the side wall surface of the vacuum chamber 11. The gas introduction means 12 is connected to gas sources 123a and 123b via gas introduction pipes 122 provided with mass flow controllers 121a and 121b, respectively. The gas sources 123a and 123b are filled with a sputtering gas such as argon or a reactive gas such as H ₂ O, O ₂ or N ₂ , and these gases are fixed in the vacuum chamber 11 by the mass flow controllers 121a and 121b. It can be introduced at a flow rate.

  A target assembly 13 is disposed at a position facing the substrate S installed in the vacuum chamber 11. The target assembly 13 includes four backing plates 131a to 131d that are substantially rectangular in a top view, and targets 132a to 132d that are installed on one side of each of the backing plates 131a to 131d and are formed in a substantially rectangular shape in a top view. .

  The backing plates 131a to 131d are manufactured to be slightly larger than the targets 132a to 132d. Such backing plates 131a to 131d are for supporting the targets 132a to 132d and also function as electrode plates, so that a voltage can be applied between the adjacent backing plates. One AC power source disposed outside the vacuum chamber 11 is provided on two adjacent backing plates. In other words, in the present embodiment, the AC power source 133a is connected to the backing plate 131a and the backing plate 131b, and the AC power source 133b is connected to the backing plate 131c and the backing plate 131d. In addition, a liquid circulation path (not shown) is provided inside the backing plates 131a to 131d so that the targets 132a to 132d can be cooled.

  The targets 132a to 132d are manufactured by a known method according to the composition of the film formed on the substrate, such as ITO, Al alloy, or Mo. The targets 132a to 132d are arranged in parallel so as to be positioned on the same plane parallel to the substrate S.

  Four magnet members 14 are provided below the target assembly 13. The magnet members 14 are formed in the same structure. The magnet member 14 has a support part 141, and a bar-shaped center magnet 142 along the longitudinal direction of the targets 132 a to 132 d and the center magnet 142 so as to be alternately arranged on the support part 141 with different polarities. A peripheral magnet 143 composed of a plurality of magnets is provided so as to surround the periphery. As a result, a closed-loop tunnel-like magnetic flux suspended in front of the targets 132a to 132d is formed, and the electrons ionized in front of the targets 132a to 132d and the secondary electrons generated by sputtering are captured, and in front of the target as a cathode. The density of the formed plasma can be increased. The magnet member 14 is movable in the width direction of the targets 132a to 132d, and is configured to form as few non-erosion regions as will be described later.

  When sputtering gas is introduced from the gas introduction means 12 into the vacuum chamber 11 configured in this way and voltages are applied to the backing plates 131a to 131d by the AC power sources 133a and 133b, the targets 132a to 132d, the substrate S, Plasma is formed in the space between. Then, by forming this plasma, the targets 132a to 132d are sputtered, the sputtered particles adhere to the substrate S, and a desired film is formed on the substrate S. In this case, as shown in FIG. 3, the target surface is divided into an erosion region A1 and a so-called non-erosion region A2, which is a region that is not eroded, depending on the plasma formation position. That is, since it is difficult to form plasma in the vicinity of the ends of the targets 132a to 132d, the targets 132a to 132d remain as non-erosion regions A2 without being eroded, and erosion due to sputtering occurs in the erosion region A1, which is another region. proceed.

  By the way, the conventional sputtering apparatus has the following problems. That is, in sputtering, sputtered particles adhere to the substrate to form a film, but depending on the direction in which the sputtered particles jump out, there are also those that adhere to the non-erosion region. Hereinafter, particles that are not directly attached to the substrate during sputtering are referred to as non-attached particles. In this case, the non-adherent particles adhering to the non-erosion region are weakly adhered to the non-erosion region, and thus are easily separated from the non-erosion region by arc discharge or the like, and become dust and float in the vacuum chamber 11. Then, the non-adherent particles that become dust may adhere to the substrate S. As described above, when a part of a film formed with non-adherent particles enters, this part has low adhesion to a part constituting another film, and the formed film is easily peeled off. As a result, the film formation characteristics deteriorate. That is, the conventional sputtering apparatus has a problem that the non-adherent particles from the non-erosion region enter the film as a foreign substance, thereby deteriorating the film forming characteristics. This needs to be suppressed.

  Therefore, in the present embodiment, the shield member 20 is provided between the targets 132a to 132d in order to suppress the adhesion of non-adherent particles to the non-erosion region A2 of the targets 132a to 132d. Hereinafter, the shield member 20 will be described in detail. A target unit is configured by the target assembly 13 and the shield member 20.

  The three shield members 20 have the same structure and are substantially rectangular in top view. The shield member 20 includes a shield main body 21 disposed between the targets 132a to 132d, and a plate-like flange portion 22 extending from the shield main body 21 so as to cover the upper surfaces of the ends in the width direction of the targets 132a to 132d. Consists of. The flange portion 22 of the shield member 20 is provided so as to cover the non-erosion region formed in the targets 132a to 132d in the width direction of the targets 132a to 132d when the shield member 20 is not provided. That is, among the reference non-erosion areas that are the references formed in the targets 132a to 132d when the shield member 20 is not provided, at least the reference non-erosion areas formed in the width direction of the targets 132a to 132d are covered. The flange portion 22 is formed to have the same width as the reference non-erosion region in the width direction. In addition, about this reference | standard non-erosion area | region, it can know beforehand how large an area | region becomes by experiment etc. Further, the shield member 20 is separated from the targets 132a to 132d and the backing plates 131a to 131d so as not to be short-circuited when a voltage is applied.

  The shield member 20 is a material to which attached particles easily adhere and is made of a high melting point material. Examples of the material of the shield member 20 include titanium, aluminum, SUS, ceramic, and the like. In the present embodiment, the material is made of titanium.

  Further, the surface of the shield member 20 is blasted (processed) to form fine irregularities (the surface roughness is 100 μm to 150 μm) although not shown. By performing the blasting process, the adhesion between the non-adhering particles and the shield member 20 is improved, thereby suppressing the particles once adhered to the shield member 42 from being peeled off again and released into the vacuum chamber 11. .

  By providing the shield member 20, the non-erosion region A2 at the ends of the targets 132a to 132d that are narrower than the reference non-erosion region can be covered with the flange portion 22, so that non-adherent particles adhere to the non-erosion region A2. Is suppressed. That is, by providing the shield member 20, the non-erosion region A2 becomes narrower than the reference non-erosion region, so that non-adherent particles can be adhered to the shield member 20 without adhering to the non-erosion region A2. Thereby, it can suppress that a non-adhesion particle adheres to non-erosion area | region A2. In this case, the non-adherent particles adhering to the shield member 20 are less likely to be peeled off from the shield member 20 than adhering to the non-erosion region A2, and do not flow again into the vacuum chamber 11 as dust. Moreover, since the non-erosion area | region A2 becomes narrower than a reference | standard non-erosion area | region by providing the shield member 20, the number of non-adhesion particles adhering to the non-erosion area | region A2 decreases. That is, it becomes difficult for non-adherent particles to adhere to the non-erosion region. Therefore, it is possible to suppress such non-adherent particles from being included in the film formed, and to prevent film peeling.

  That is, in this embodiment, non-adherent particles that have been sputtered from the targets 132 a to 132 d and jumped into the vacuum chamber 11 but could not adhere to the substrate are adhered to the shield member 20, and are brought into close contact with the shield member 20. The non-adherent particles are prevented from adhering to the non-erosion region A2, thereby improving the film forming characteristics of the sputtering apparatus 1.

  Further, by providing the shield member 20 between the targets 132a to 132d as described above, non-adherent particles can be prevented from adhering across the targets 132a to 132d and causing a short circuit between the targets 132a to 132d. be able to. For example, if the shield member is provided so as to be buried only between the targets 132a to 132d, it is not possible to prevent non-adherent particles from adhering to the non-erosion region A2 as described above, and the film peels off. Therefore, it is not possible to obtain a sputtering apparatus with good film formation characteristics. And in this embodiment, since the edge part of the width direction of target 132a-132d is covered, a surface area is large compared with the case where a shield member is provided so that it may be embedded only between targets 132a-132d. Therefore, more non-adhering particles can be adhered, and re-adhesion of non-adhering particles to the substrate S can be suppressed.

  As described above, the flange portion 22 of the shield member 20 is formed so as to cover the non-erosion region A2 at the ends of the targets 132a to 132d, and the targets 132a to 132d are arranged in the width direction, respectively. Each end is covered 3 to 7 mm. If it is smaller than 3 mm, the non-erosion region A2 of the targets 132a to 132d cannot be covered. On the other hand, if it is larger than 7 mm, the target 132a to 132d is larger than the reference non-erosion region, and the targets 132a to 132d are eroded. This is because the area is covered and the use efficiency of the targets 132a to 132d is low, and desired film formation characteristics cannot be obtained. In the present embodiment, the flange portion 22 of the shield member 20 covers each end in the width direction of the targets 132a to 132d by about 5 mm so as to be substantially the same as the width of the reference non-erosion region of the targets 132a to 132d. ing.

  Moreover, the space | interval of the flange part 22 and the targets 132a-132d should just be the space | interval of the uppermost surface of the targets 132a-132d before use and the lower surface of the flange part 22 about 2-15 mm. If the distance is less than 2 mm and the non-adherent particles are deposited, the flange portion 22 and the targets 132a to 132d are connected to each other, which may cause a short circuit. On the other hand, if it exceeds 15 mm, the distance between the lower surface of the flange portion 22 and the targets 132a to 132d is too large, and non-adherent particles do not adhere to the shield member 20, and adhere to the non-erosion region A2 of the targets 132a to 132d. End up. In this embodiment, it is 10 mm.

  A support member 23 is provided behind the backing plates 131a to 131d to hold the shield member 20. The support member 23 includes a plate-like portion 231 and a protruding portion 232 extending at the center in the width direction of the plate-like portion 231 so as to be disposed between the backing plates 131a to 131d. The protruding portion 232 and the flange portion 22 are fixed by a fastening member 233 provided at a distance from the center portion in the width direction of the flange portion 22. The support member 23 is grounded to the ground potential. Thereby, the shield members 20 are each at ground potential, and the provision of the shield member 20 does not cause a short circuit between the targets.

  Hereinafter, another embodiment of the present invention will be described.

(Embodiment 2)
A sputtering apparatus according to the second embodiment will be described with reference to FIG. In the second embodiment, the targets 132a to 132d of the first embodiment shown in FIGS. 1 to 3 are the same as the sputtering apparatus shown in the first embodiment except that targets having different cross-sectional shapes are used. .

  The targets 41a and 41b in the sputtering apparatus of this embodiment are tapered at the ends in the width direction. Thus, since the edge part of the width direction of target 41a and 41b inclines, the distance with the lower surface of the flange part 22 of the shield member 20 is made larger than the sputtering apparatus 1 concerning Embodiment 1. FIG. Here, only the vicinity of the targets 41a and 41b is shown for explanation.

  Thus, by providing a taper at the ends of the targets 41a and 41b, compared to a case in which no taper is provided at the ends of the targets 41a and 41b (that is, in the case of the targets 132a to 132d in the first embodiment) Particles are unlikely to adhere to the non-erosion region A2 (see FIG. 3). This is because the end portion where non-adherent particles are likely to adhere is a tapered surface, so that the plasma also flows to the lower surface side of the flange portion 22, so that the non-erosion region A2 can be formed even narrower than in the first embodiment. The number of non-adhering particles adhering to the non-erosion region A2 can be further reduced. That is, with this configuration, non-adherent particles are less likely to adhere to the non-erosion region A2. Further, since the distance between the targets 41a and 41b and the flange portion 22 of the shield member 20 in the sputtering apparatus 2 is increased, non-adherent particles form a film, and the targets 41a and 41b and the flange portion 22 of the shield member 20 are electrically connected. It is possible to suppress a short circuit due to the connection. If the height of the shield member 20 is increased in order to increase the distance between the targets 41a and 41b and the flange portion 22 of the shield member 20 in order to prevent a short circuit, non-adherent particles adhere to the non-erosion region A2. I cannot suppress it. Therefore, it is preferable to provide tapered surfaces at both ends in the width direction of the targets 41a and 41b as in this embodiment.

  In addition, by providing a taper at the ends of the targets 41a and 41b, the distance between the targets 41a and 41b and the flange portion 22 is large, so that the plasma can easily flow around to the lower surface side of the flange portion 22 and stably generate plasma. Can continue to form. In addition, since the plasma is likely to circulate also to the lower surface side of the flange portion 22, the non-erosion region A2 is less likely to be formed in the case of the sputtering apparatus according to the present embodiment than in the sputtering apparatus 1, and the targets 41a and 41b are formed. While being able to use efficiently, since there are few non-erosion area | regions A2, it can also suppress more that non-adhesion particle | grains adhere to this area | region.

As a reference example, film formation was performed using the sputtering apparatus according to the second embodiment. As film forming conditions, pressure: 0.52 Pa, applied voltage: 40 V, target material: indium oxide-zinc oxide based transparent electrode material, sputtering gas: mixed gas of Ar, O ₂ , flow rate: Ar = 950 sccm, O ₂ = It was 12 sccm.

  As a comparative example, in the sputtering apparatus 1 according to the first embodiment, the same sputtering apparatus is used under the same film formation conditions except that the flange portion 22 is not provided, that is, a shield member including only the shield body 21 is provided. Membrane was performed.

  In each case of the reference example and comparative example, the number of foreign particles adhering to the substrate after film formation, that is, the number of non-adhering particles was measured with a pattern inspection device (trade name FPI-6590, manufactured by Orbotech), and the number was compared. did. The results are shown in FIG. As shown in FIG. 5, in the case of the reference example, the number of foreign particles was reduced as compared with the comparative example, and it was found that the film formation characteristics were improved in the sputtering apparatus according to the second embodiment.

(Embodiment 3)
The sputtering apparatus of this embodiment is demonstrated using FIG. In the third embodiment, the shield member of the second embodiment is the same as the sputtering apparatus shown in the second embodiment except that a shield member having a different shape is used.

  In the present embodiment, the shield member 42 is provided with a recess on the entire surface thereof. Thereby, the surface area of the shield member 42 can be further increased, and more non-adherent particles can be adhered. Of course, this shield member 42 is also blasted as described above.

  According to the sputtering apparatus according to each of the first to third embodiments described above, film formation characteristics can be improved.

(Other embodiments)
The present invention is not limited to Embodiments 1 to 3 described above. For example, although the number of target installations is four in this embodiment, it is of course not limited to this. For example, the target may be composed of only one sheet.

  The shield member 20 only needs to be able to cover at least a part of the end portion of the target, that is, the non-erosion region formed on the target when the shield member 20 is not provided. For example, the shield member 20 is provided only at the end portion in the longitudinal direction. It may be done.

  In the second embodiment, the ends of the targets 41a and 41b are tapered to form a slope. However, the present invention is not limited to this, and the taper may be provided on the lower surface side of the shield member 20. In this way, the distance between the shield member 20 and the target can be increased. The shield member 20 may be any member that can cover at least the end portion of the upper surface of the target. For example, the shield member 20 may include only the flange portion 22.

  In Embodiments 1 to 3 described above, the shield member 20 is not provided outside the target 132a and the targets 132a to 132d of the target 132d in the juxtaposed direction, but the shield member 20 is also provided outside the juxtaposed direction. May be provided. That is, in the first embodiment, each of the targets 132a to 132d is covered with the shield member 20 at both ends in the width direction. By comprising in this way, since non-erosion area | region A2 can be covered more reliably, the non-adhesion particle | grains adhering to non-erosion area | region A2 can be reduced. As shown in the first to third embodiments, by providing the shielding member 20 at least between the targets facing the substrate S, the non-adherent particles adhering to the non-erosion region A2 in the region facing the substrate S can be sufficiently obtained. Since it can be reduced, the possibility that non-adherent particles are mixed into the film formed on the substrate can be sufficiently reduced, and thereby the film formation characteristics can be sufficiently improved.

  The sputtering apparatus of the present invention has high film forming characteristics. Therefore, it can be used in the semiconductor element manufacturing industry and the solar cell element manufacturing industry.

DESCRIPTION OF SYMBOLS 1 Sputtering apparatus 11 Vacuum chamber 12 Gas introduction means 13 Target assembly 14 Magnet member 20 Shield member 21 Shield main body 22 Flange part 23 Support member 41a, 41b Target 42 Shield member 121a, 121b Mass flow controller 122 Gas introduction pipe 123a Gas source 131a- 131d Backing plate 132a-132d Target 133a-133b AC power supply 141 Support part 142 Central magnet 143 Peripheral magnet 231 Plate part 232 Projection part 233 Fastening member A1 Erosion area A2 Non-erosion area S Substrate

Claims (3)

A sputtering apparatus comprising: a vacuum chamber; a power source for applying a voltage to a target provided at a position facing a substrate installed in the vacuum chamber; and a gas introducing means for introducing a gas into the vacuum chamber. And
A plurality of the targets are provided side by side with a predetermined interval, and at the end portion of the target, a shield member that covers the upper surface of the end portion and has a ground potential , The shield member covers the upper surface of the opposite end portions of the adjacent targets, and the width of the upper portion of the shield member covering the upper surface of the end portion of the target is the same as that when the shield member is not provided. A sputtering apparatus having the same width as the upper part of a non-erosion region formed on a target. The target, the the region covered with the shield member, characterized in that the taper is provided according to claim 1 Symbol placement of the sputtering apparatus. The sputtering apparatus according to claim 1 or 2, characterized in that a further shield member so as to cover the upper surface of the end portion of both ends of the target arrangement direction of the target.

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