WO2020164685A1

WO2020164685A1 - Cathode drive unit, sputtering cathode and method for assembling a cathode drive unit

Info

Publication number: WO2020164685A1
Application number: PCT/EP2019/053411
Authority: WO
Inventors: Joachim Sonnenschein; Daniel SCHÄFER-KOPYTTO; Tobias Bergmann
Original assignee: Applied Materials, Inc.
Priority date: 2019-02-12
Filing date: 2019-02-12
Publication date: 2020-08-20
Also published as: CN113454752A; KR20210124412A; CN113454752B

Abstract

A cathode drive unit (100) for a deposition source is described. The cathode drive unit includes a cathode support (102); and a belt drive for rotating the cathode support. The belt drive includes a first pulley (112) coupled to a shaft (103) driving the cathode support; a drive assembly (120) having a second pulley (114); a belt (116) engaging with the first pulley and the second pulley; a guide (130) supporting at least a portion of the drive assembly; and a tensioner (140) providing a force to at least the portion of the drive assembly for moving at least the portion of the drive assembly along the guide.

Description

CATHODE DRIVE UNIT, SPUTTERING CATHODE AND METHOD FOR ASSEMBLING A CATHODE DRIVE UNIT

FIELD

[0001] Embodiments described herein relate to layer deposition by sputtering from a target. Particularly, embodiments of the present disclosure may relate to a rotatable cathode and a cathode drive unit (CDU). Some embodiments particularly relate to sputtering layers on large area substrates. Embodiments described herein relate specifically to a sputter deposition apparatus including one or more cathode assemblies, particularly rotatable cathode assemblies having a cathode drive unit for rotation of the cathode, particularly a rotatable, i.e. cylindrical cathode.

BACKGROUND

[0002] In many applications, it is necessary to deposit thin layers on a substrate. The substrates can be coated in one or more chambers of a coating apparatus. The substrates may be coated in a vacuum, using a vapor deposition technique.

[0003] Several methods are known for depositing a material on a substrate. For instance, substrates may be coated by a physical vapor deposition (PVD) process, a chemical vapor deposition (CVD) process or a plasma enhanced chemical vapor deposition (PECVD) process etc. The process is performed in a process apparatus or process chamber where the substrate to be coated is located. A deposition material is provided in the apparatus. A plurality of materials, and also oxides, nitrides or carbides thereof, may be used for deposition on a substrate. Coated materials may be used in several applications and in several technical fields. For instance, substrates for displays are often coated by a physical vapor deposition (PVD) process. Further applications include insulating panels, organic light emitting diode (OLED) panels, substrates with thin film transistors (TFT), color filters or the like.

[0004] For a PVD process, the deposition material can be present in the solid phase as a target. By bombarding the target with energetic particles, atoms of the target material, i.e. the material to be deposited, are ejected from the target. The atoms of the target material are deposited on the substrate to be coated. In a PVD process, the sputter material, i.e. the material to be deposited on the substrate, may be arranged in different ways. For instance, the target may be made from the material to be deposited or may have a backing element on which the material to be deposited is fixed. The target including the material to be deposited is supported or fixed in a predefined position in a deposition chamber. In the case where a rotatable target is used, the target is connected to a rotating shaft or a connecting element connecting the shaft and the target.

[0005] Segmented planar, monolithic planar and rotatable targets may be used for sputtering. Due to the geometry and design of the cathodes, rotatable targets typically have a higher utilization and an increased operation time than planar ones. The use of rotatable targets may prolong service life and reduces costs.

[0006] Sputtering can be conducted as magnetron sputtering, wherein a magnet assembly is utilized to confine the plasma for improved sputtering conditions. The plasma confinement can be utilized for adjusting the participle distribution of the material to be deposited on the substrate.

[0007] Cathode drive units four rotating the target and/or the cathode, respectively, are subject to maintenance. Particularly for large area substrates having a plurality of cathodes for depositing material on a substrate, maintenance may be time-consuming. Accordingly, it is beneficial to provide an improved cathode drive unit, an improved cathode, an improved deposition system, and an improved method of installing a cathode drive unit.

SUMMARY

[0008] In light of the above, a method for inspecting a specimen with an array of beamlets of charged particles and a charged particle multi-beam device according to the independent claims are provided. Further aspects, advantages, and features are apparent from the dependent claims, the description, and the accompanying drawings.

[0009] According to one embodiment, a cathode drive unit for a deposition source is provided. The cathode drive unit includes a cathode support; and a belt drive for rotating the cathode support. The belt drive includes a first pulley coupled to a shaft driving the cathode support; a drive assembly having a second pulley; a belt engaging with the first pulley and the second pulley; a guide supporting at least a portion of the drive assembly; and a tensioner providing a force to at least the portion of the drive assembly for moving at least the portion of the drive assembly along the guide.

[0010] According to one embodiments, a rotatable cathode for vacuum processing of a substrate is provided. The cathode includes a cathode drive unit according to any of the embodiments of the present disclosure to rotate a target of the rotatable cathode.

[0011] According to one embodiment, a method of tensioning a belt of a belt drive for a rotation of a cathode is provided. The method includes moving at least a portion of a drive assembly in a mounting position; mounting the belt to a cathode support and the drive assembly; connecting at least the portion of the drive assembly to a tensioner; moving at least the portion of the drive assembly against a force of the tensioner up to a stopped position; and optionally fixing the position of at least the portion of the drive assembly at the stopped position.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] A full and enabling disclosure to one of ordinary skill in the art is set forth more particularly in the remainder of the specification including reference to the accompanying drawings wherein:

FIG. 1 shows a schematic view of a cathode drive unit for rotation of a cathode according to embodiments described herein;

FIG. 2 shows a schematic view of a portion of a rotatable cathode including a cathode drive unit and a drive unit for moving a magnet assembly according to embodiments of the present disclosure; FIGS.3 A to 3C show enlarged views in different directions of a cathode drive unit according to embodiments of the present disclosure;

FIG. 4 shows a flow chart illustrating a method of installing a cathode drive unit according to embodiments described herein; and

FIG. 5 shows a deposition apparatus according to embodiments described herein having a a cathode drive unit with a self-adjusting belt tensioner.

DETAILED DESCRIPTION

[0013] Reference will now be made in detail to the various embodiments, one or more examples of which are illustrated in the figures. Within the following description of the drawings, the same reference numbers refer to same components. Generally, only the differences with respect to individual embodiments are described. Each example is provided by way of explanation and is not meant as a limitation. Further, features illustrated or described as part of one embodiment can be used on or in conjunction with other embodiments to yield yet a further embodiment. It is intended that the description includes such modifications and variations.

[0014] The drawings are schematic drawings which are not drawn to scale. Some elements in the drawings may have dimensions which are exaggerated for the purpose of highlighting aspects of the present disclosure and/or for the sake of clarity of presentation.

[0015] Embodiments described herein relate to a cathode drive unit, a rotatable cathode, and a deposition apparatus for depositing a material on a substrate. In a deposition process or coating process, a layer of target material is deposited on a substrate. The substrate is coated with the material. The terms “coating process” and “deposition process” are used synonymously herein.

[0016] A deposition apparatus according to embodiments described herein may be configured for deposition on vertically oriented substrates. The term“vertically oriented” may include substrates which are arranged at a small deviation from exact verticality, e.g. an angle of up to 10° or even 15° may exist between the substrate and the exact vertical direction. A deposition apparatus according to embodiments described herein may be configured for deposition on large area substrates. [0001] A substrate as described herein may be a large area substrate. The term“substrate” as used herein includes substrates which are typically used for display manufacturing. For example, substrates as described herein can be substrates which are typically used for an LCD (Liquid Crystal Display), a OLED panel, and the like. For instance, a large area substrate can be GEN 4.5, which corresponds to about 0.67 m² substrates (0.73 x 0.92m), GEN 5, which corresponds to about 1.4 m² substrates (1.1 m x 1.3 m), GEN 6, which corresponds to about 2.8 m² substrates (1.85 m x 1.5 m), GEN 7.5, which corresponds to about 4.29 m² substrates (1.95 m x 2.2 m), GEN 8.5, which corresponds to about 5.7m² substrates (2.2 m x 2.5 m), or even GEN 10, which corresponds to about 8.7 m² substrates (2.85 m x 3.05 m). Even larger generations such as GEN 11 and GEN 12 and corresponding substrate areas can similarly be implemented.

[0002] The term“substrate” as used herein shall particularly include substantially inflexible substrates, e.g., a wafer, slices of transparent crystal such as sapphire or the like, or a glass plate. In particular, the substrates can be glass substrates and/or transparent substrates. The present disclosure is not limited thereto and the term“substrate” may also embrace flexible substrates such as a web or a foil. The term“substantially inflexible” is understood to distinguish over“flexible”. Specifically, a substantially inflexible substrate can have a certain degree of flexibility, e.g. a glass plate having a thickness of 0.5 mm or below, wherein the flexibility of the substantially inflexible substrate is small in comparison to the flexible substrates.

[0017] A deposition apparatus according to embodiments described herein can include one or more cathodes or cathode assemblies, particularly a plurality of cathode assemblies. A cathode assembly should be understood as an assembly which is adapted for being used as a cathode in a coating process, such as a sputter deposition process.

[0018] A cathode assembly according to embodiments described herein may be a rotatable cathode assembly. A cathode assembly may include a target, particularly a rotatable target, i.e. a cylindrical target. A rotatable target may be rotatable around a rotation axis of the rotatable target. A rotatable target may have a curved surface, for example a cylindrical surface. The rotatable target may be rotated around the rotation axis being the axis of a cylinder or a tube. A cathode assembly may include a backing tube. A target material forming the target, which may contain the material to be deposited onto a substrate during a coating process, may be mounted on the backing tube. Alternatively, the target material may be shaped as a tube without being provided on a backing tube.

[0019] A deposition apparatus for large area substrates may include a plurality of cathodes. For example, four or more, such as six or more or even 10 or more cathodes may be provided. Particularly for vertical substrate processing, a cathode drive unit may be provided at the bottom of the cathode, for example, below the vacuum chamber in which the cathodes are operated. The rotatable cathode can be driven by belt drives. After assembling of the geared belt drives, tension can be generated on the belt and measured with a belt tension meter. In the event the tension is not in a specific range, at least a portion of the assembling is redone to adjust the belt tension. This procedure may prolong maintenance and/or assembly of a vacuum processing system, particularly if a plurality of cathodes needs to be assembled and/or maintained. Additionally, space restrictions below the vacuum chamber may complicate the procedure.

[0020] Embodiments of the present disclosure provide a cathode drive unit having a self- adjusting belt tensioner. The assembly of the belt drive, for example, the geared belt drive generates specific tension. An additional measuring can be avoided, for example in areas which are difficult to access. Accordingly, assembly time and/or maintenance time can be reduced, for example, by elimination of belt tension measurement in areas which are difficult to access and potential subsequence adjustment of the belt tension. Yet further, a predetermined belt tension can be repeatedly provided. This may further protect bearings from overload.

[0021] FIG. 1 shows a cathode drive unit 100. The cathode drive unit 100 is configured for rotating a cathode 104 around the axis 101. The cathode drive unit includes a cathode support 102 supporting the cathode 104. Further, a shaft 103 is coupled to the cathode support 102. A first pulley 112 is coupled to the shaft 103. For example, the first pulley 112 and a portion of the shaft 103 can be provided in the housing 106 of the cathode drive unit 100. The rotation of the first pulley 112 results in a rotation of the cathode support 102 and, thus, in a rotation of the cathode 104 around the axis 101.

[0022] The first pulley 112 is driven by a belt 116. The belt 116 is driven by a rotation of a second pulley 114 around the axis 115. The second pulley 114 is rotated by a drive assembly 120, for example a geared drive configured for rotation of the second pulley 114 around the axis 115. The distance 117 between the axis 101 and the axis 115 provides a tension to the belt 116. One or more guides 130 can be provided to move the drive assembly 120 or at least a portion of the drive assembly as indicated by arrow 132. According to some embodiments, which can be combined with other embodiments described herein, the one or more guides can be one or more linear guides.

[0023] One or more tensioners 140 can be provided. According to embodiments of the present disclosure, a tensioner can be configured to provide a predetermined tension to the belt 160. Further details, aspects, features and modifications of a belt drive according to embodiments of the present disclosure, for example, a self-adjusting belt drive are described with respect to figs. 3A to 3C below. According to some embodiments, which can be combined with other embodiments described herein, the tensioner can be selected from a spring, pneumatic cylinder, hydraulic cylinder.

[0024] FIG. 2 shows portion of the rotatable cathode for vacuum processing of the substrate, particularly a large area substrate, and more particularly a vertically oriented large area substrate. The cathode 104 is supported by the cathode support 102. A magnet assembly 202 can be provided within the cathode 104.

[0025] A magnet assembly may be arranged in a cathode or cathode assembly. A magnet assembly may be surrounded by the target material. A magnet assembly may be arranged so that the target material sputtered by the cathode assembly is sputtered towards a substrate. A magnet assembly may generate a magnetic field. The magnetic field may cause one or more plasma regions to be formed near the magnetic field during a sputter deposition process. The position of the magnet assembly within a cathode assembly affects the direction in which target material is sputtered away from the cathode assembly during a sputter deposition process. The magnet assembly can confine the plasma during sputtering. An improved sputtering process can be provided with the magnet assembly.

[0026] According to some embodiments, which can be combined with other embodiments described herein, the magnet assembly can be moved within the cathode or the target, respectively. Accordingly, the cathode 104 or the target, respectively may rotate around the axis 101. Further, the magnet assembly 202 may rotate around an axis parallel to the axis 101. Accordingly, the magnet assembly 202 can be provided at various angular coordinates relative to the axis 101. The magnet assembly can wobble back and forth in order to move the plasma relative to at least one of a substrate, the vacuum chamber of the vacuum deposition apparatus, and the cathode drive unit 100, particularly a housing 106 of the cathode drive unit. A movement of the magnet assembly 102, for example, a movement by an angle, can result in a varying deposition direction of the sputtering cathode. Accordingly, layer uniformity during deposition can be improved by moving the magnet assembly. A movement may be continuous or step like.

[0027] In FIG. 2, a rotation of the cathode support 102 and the cathode 104 (or target, respectively) can be provided similar to the embodiments described herein, for example, as described above with respect to FIG. 1. Further, the magnet assembly 202 can be connected to a further shaft 203 for rotation of the magnet assembly. The further shaft may be rotated by a belt drive including the pulley 212, the belt 216 and the pulley 214. The pulley 214 is rotated around the axis 215 by drive assembly 220, for example, a geared drive assembly. Yet further, similar to the embodiments of cathode drive unit is described with respect to FIG. 1, one or more guides 230 and one or more tensioners 240 can be provided for a movement of the drive assembly 220 or at least a portion of the drive assembly as indicated by arrow 232. The drive or drive assembly 220 may be operated to move the pulley 214 back and forth in order to move the magnet assembly 202 back and forth, i.e. back and force by an angle, for example, in angular coordinate. Further details, aspects, and features may be provided similar to the embodiments described with respect to FIG. 1 and including the details of FIGS. 3 A to 3C below.

[0028] Further details of a self-adjusting belt drive that can be utilized in a cathode drive unit and/or a magnet assembly movement as described in the present disclosure can be explained with respect to figs. 3A to 3C.

One or more guides 130 can be coupled to a housing of the cathode drive unit, for example, the housing 106 shown in FIG. 1. The one or more guides can be coupled (box 501 in FIG. 4) to a housing of the cathode drive unit by coupling a plate 330 the housing, for example a main housing. The plate 330 can be an electrically insulating plate. The insulation plate can include the one or more guides 130 and one or more tensioners 140. As shown in FIG. 3B, the plate 330 may exemplarily be coupled to the housing with screws 332. Further screws may be provided. For example, the further screws may be provided at the left hand side in the few shown in FIG. 3A. Accordingly, the one or more guides 130 and one or more tensioners 140 are coupled to main housing of the drive unit. According to some embodiments, which can be combined with other embodiments described herein, the guide can be provided by at least one of a nose or a groove. Additionally or alternatively, the guide can be provided by a roller bearing or a plain bearing.

[0029] As exemplarily shown in FIG. 3B, the guide 130 can include a guide groove 331. Further, additionally or alternatively, the guide 130 can be provided as a linear guide. As illustrated in FIG. 3B, the one or more guides 130, for example, a groove 331, can receive the drive assembly 120, for example a gear unit of the drive assembly. The drive assembly or the gear unit, respectively, can be inserted (step 503 in FIG. 4) in the housing e.g. by a sliding movement along the guide 130 or along the guides 130.

[0030] After insertion of the drive 120, the second pulley 114 is close to a final position utilized for operation of the sputtering cathode. According to some embodiments, which can be combined with other embodiments described herein, the housing, the plate 330, and/or the guide 130 may provide a stop. The stop refers to position at which the drive or the gear unit, respectively, is fully inserted in the housing. Accordingly, as indicated by box 505 the belt 116 can be placed at the first pulley 112 and the second pulley 114. According to some embodiments, which can be combined with other embodiments described herein, a first stop, e.g. a hard stop, defining an end position for insertion of at least the portion of the drive assembly relative to the guide can be provided.

[0031] According to some embodiments, which can be combined with other embodiments described herein, the belt can be a toothed belt. Further, the first pulley and the second pulley can be a toothed pulley.

[0032] A further plate 350, such as a locking plate or a locking strip, can be coupled (see box 507) to the tensioner 140. According to some embodiments, which can be combined with other embodiments described herein, the tensioner can be a spring, a pneumatic cylinder, or a hydraulic cylinder, which can be connected to a fastener 340 (see FIG. 3B) reaching through the plate 330. The further plate 350 can be coupled to the tensioner 140 by coupling the further plate to the fastener 340. For example, screws 352 can be utilized too fast and the further plate, such as the locking strip, to the one or more tensioners of the blade 330.

[0033] A tensioning screw 360 can be coupled (see box 509) to the drive assembly or the gear unit of the drive, respectively. Actuation of the tensioning screw pulls the drive assembly away from the first axis 101 (see FIG. 1) to increase the distance 117 of the first axis 101 and the second axis 115. The drive assembly and/or the gear unit, i.e. at least a portion of the drive assembly, are pulled towards the locking strip. The second stop is provided for the movement of the portion of the drive assembly. The belt 116 is tightened against the force, for example a spring force, of the one or more tensioners. According to some embodiments, which can be combined with other embodiments described herein, a second stop, e.g. a hard stop, defining an end position for tensioning the belt can be provided.

[0034] At the second stop, the position of the portion of the drive assembly that has been moved, for example, gear unit, is secured. The assembly of the first pulley, the belt, the second pulley and the moving component of the drive assembly is fixed in position (see box 511). For example, screws 362, i.e. fasting screws can be provided through the plate 330, for example, the electrically insulating plate, into the locking strip. Thus, according to some embodiments, which can be combined with other embodiments described herein, a lock configured to be secured in a tensioning position is provided.

[0035] A belt tensioner is integrated in the fixation of the gearbox and/or the drive assembly, respectively. For example, the belt tensioner can be a spring-loaded belt tensioner. Due to the stop position(s) and the predetermined spring force, a predetermined attention can be achieved in a repeatable manner.

[0036] A deposition apparatus 500 according to embodiments described herein may be configured for vacuum deposition and is exemplarily shown in FIG, 5. The deposition apparatus 500 may include a processing chamber, particularly a vacuum chamber 510. A cathode assembly or cathode 104 as described herein, or at least a part of the cathode assembly, may be arranged in the processing chamber.

[0037] FIG. 5 shows a cross-section of a deposition apparatus 500 according to embodiments described herein. The cross-section is in a direction parallel to a rotation axis of the cathode 104.

[0038] A deposition apparatus 500 according to embodiments described herein may be a sputter deposition apparatus. A cathode 104 or a cathode assembly as described herein may be a sputter cathode assembly. The cathode assembly may include a target. The target may be rotatable around a rotation axis of the target. The target may have a curved, e.g. substantially cylindrical, surface. The cathode assembly may include a magnet assembly 202 as described herein. The magnet assembly may be arranged in the cathode. [0039] A cathode drive unit 100 may be configured for supplying power to the cathode and for rotation of the cathode with a belt drive according to embodiments described herein, e.g. a belt drive with a self-adjusting belt tensioner. A cathode drive unit may include or be connectable to a power supply for supplying power to the cathode. Additionally or alternatively, a cathode drive unit may be configured for supplying water or coolant to the cathode and/or to a coolant receiving enclosure. A cathode drive unit may include or be connectable to a water or coolant supply for supplying water or coolant to the cathode. As described above, a cathode drive unit is configured for driving a rotation of the cathode and/or a target, respectively. A cathode drive unit as described herein may be referred to as an end block or cathode drive block. The cathode drive unit can be provided below the target.

[0040] As indicated by arrows 11 in FIG. 5, material from the target is sputtered towards a substrate. The substrate may be supported by a carrier 531. The carrier can be moved into and out of the vacuum chamber 510 by a transportation system 530. For example, the transportation system can be a roller base transportation system, wherein the carrier is supported by rollers in the vacuum chamber 510. As shown in FIG. 5, the transportation system 530 may be a magnetic levitation system having, for example, a levitation unit 532 and a drive unit 534 four moving the carrier 531 through the vacuum chamber. As shown in FIG. 5, the transportation system 530 can be arranged to be above the carrier and the drive unit can be arranged to be below the carrier. Yet, depending on the magnetic levitation system and further arrangements in the system, the levitation unit 532 can be above or below the carrier. Additionally or alternatively, the drive unit 534 can be above or below the carrier. The cathode drive unit 100 shown in FIG. 5 can be a cathode drive unit according to any of the embodiments described in the present disclosure.

[0041] While the foregoing is directed to embodiments of the disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

CLAIMS:

1. A cathode drive unit for a deposition source, comprising: a cathode support; a belt drive for rotating the cathode support, comprising: a first pulley coupled to a shaft driving the cathode support; a drive assembly having a second pulley; a belt engaging with the first pulley and the second pulley; a guide supporting at least a portion of the drive assembly; and a tensioner providing a force to at least the portion of the drive assembly for moving at least the portion of the drive assembly along the guide.

2. The cathode drive unit according to claim 1, wherein the tensioner is selected from a spring, pneumatic cylinder, hydraulic cylinder.

3. The cathode drive unit according to any of claims 1 to 2, further comprising: a first stop defining an end position for insertion of at least the portion of the drive assembly relative to the guide.

4. The cathode drive unit according to any of claims 1 to 3, further comprising: a second stop defining an end position for tensioning the belt.

5. The cathode drive unit according to any of claims 1 to 4, wherein the guide is provided at a portion of a plate, particularly an electrically insulating plate.

6. The cathode drive unit according to claim 5, wherein the tensioner is coupled to the plate.

7. The cathode drive unit according to any of claims 1 to 6, wherein the guide is provided by at least one of a nose or a groove.

8. The cathode drive unit according to any of claims 1 to 7, further comprising: a second plate configured to engage with at least the portion of the drive assembly.

9. The cathode drive unit according to any of claims 1 to 8, further comprising: a lock configured to be secured in a tensioning position.

10. A rotatable cathode for vacuum processing of a substrate, comprising: a cathode drive unit according to any of claims 1 to 9 configured to rotate a target of the rotatable cathode.

11. The rotatable cathode according to claim 10, further comprising: a further belt drive configured to rotate a magnet assembly within the target, the further belt drive comprises: a further first pulley coupled a shaft driving the cathode support; a further drive assembly having a further second pulley; a further belt engaging with the further first pulley and the further second pulley; a further guide supporting at least a portion of the further drive assembly; and a further tensioner providing a force to at least the portion of the further drive assembly for moving at least the portion of the further drive assembly along the further guide.

12. The rotatable cathode according to any of claims 10 to 11, wherein the tensioner is selected from a spring, pneumatic cylinder, hydraulic cylinder.

13. The rotatable cathode according to any of claims 10 to 12, further comprising: a first stop defining an end position for insertion of at least the portion of the drive assembly relative to the guide; and a second stop defining an end position for tensioning the belt.

14. The rotatable cathode according to any of claims 10 to 13, further comprising: a further lock configured to be secured in a tensioning position of the further belt.

15. A method of tensioning a belt of a belt drive for a rotation of a cathode, comprising: moving at least a portion of a drive assembly in a mounting position; mounting the belt to a cathode support and the drive assembly; connecting at least the portion of the drive assembly to a tensioner; moving at least the portion of the drive assembly against a force of the tensioner up to a stopped position; and optionally fixing the position of at least the portion of the drive assembly at the stopped position.