Shutter device and film formation device

Abstract

A shutter device according to an aspect of the present invention comprises: a housing having an opening; a plurality of shutter plates; and a plurality of drive units. The plurality of drive units are connected to the plurality of shutter plates, and are configured so as to change the attitude of the plurality of shutter plates. At least a partial region of the opening is a passing region through which sputtered particles emitted from the target pass. The plurality of drive units are configured to change the state of the shutter plate to a closed state, a parallelized state, or an open state. In the closed state, the plurality of shutter plates are arranged so as to block at least the passing region for the sputtered particles. In the parallelized state, the shutter plates are arranged in such a manner that a part of the plurality of shutter plates is arranged in the passing region for the sputtered particles and the flying directions of the sputtered particles become parallel to each other. In the open state, the plurality of shutter plates retreat from the passing region for the sputtered particles.

Description

Shutter device and film forming device

[0001] The present invention relates to a shutter device and a film forming apparatus. This application claims priority to Japanese Patent Application No. 2023-141340, filed on August 31, 2023, the contents of which are incorporated herein by reference.

[0002] Conventionally, for example, in a film formation process in the fabrication of semiconductor devices, a film formation apparatus using a sputtering method (hereinafter referred to as a "sputtering apparatus") has been used. With the recent trend toward finer wiring patterns, sputtering apparatuses for such applications are strongly required to be able to form films with good coverage over the entire surface of the substrate to be processed, even in fine holes and trenches with high aspect ratios, such as depth-to-width ratios exceeding 3. In other words, there is a strong demand for improved coverage.

[0003] In a typical sputtering device, the first step in discharging sputter particles from the target is to apply a negative voltage to a target placed in a vacuum chamber filled with argon gas (hereinafter referred to as "ignition"). This ionizes the sputter gas (e.g., argon gas) and causes it to collide with the target, discharging sputter particles from the target surface. For example, when sputtering is performed using a target made of a wiring thin film material such as Ta or Cu, Ta atoms or Cu atoms disperse from the target as sputter particles. The dispersing atoms adhere to the workpiece and form a thin film. The substrate on which the film is to be formed is positioned opposite the target at a predetermined distance in the vacuum chamber.

[0004] In addition, in a DC magnetron sputtering device, a magnetic field is formed on the target surface by a magnetic field generator (e.g., a permanent magnet) provided on the back surface of the target. In this state, by applying a negative voltage to the target, sputtering gas ions collide with the target surface, and target material atoms and secondary electrons are ejected from the target. By circulating these secondary electrons in the magnetic field formed on the target surface, the frequency of ionization collisions between the sputtering gas (an inert gas such as argon gas) and the secondary electrons is increased, increasing plasma density and enabling thin film formation (see, for example, Patent Document 1).

[0005] Japanese Patent Application Publication No. 2008-47661

[0006] The inventors discovered that during film formation in fine holes and trenches, the film formation process during the unstable plasma stage immediately after applying a negative potential to the target significantly affects the occurrence of sputtered particle aggregation on the sidewalls of the fine holes and trenches. It is speculated that the cause of such sputtered particle aggregation is the quality of the film formed by the sputtered particles in the initial stage before the plasma stabilizes. Poor film quality in the initial stage affects film formation after the plasma stabilizes, resulting in poor film quality. Before wiring patterns became finer, the film thickness was relatively thick, so the amount of film formed during ignition was relatively small and not a problem. However, in recent years, as wiring patterns have become finer, the film thickness formed during ignition (at ignition) has become significant relative to the required film thickness.

[0007] In addition, a conventional technique is known in which a shutter device is inserted between the target and the workpiece to suppress film formation when the plasma is not stable. However, this technique has problems such as the possibility of plasma leaking and contaminating the chamber when the shutter is opened and closed, the narrow shutter opening, and the need to enlarge the chamber to enlarge the shutter opening.

[0008] Furthermore, to improve coverage of fine holes and trenches with high aspect ratios, it is preferable to parallelize the flight direction of sputtered particles. To achieve this, a collimator device must be installed in the chamber. However, this sometimes makes it unavoidable to increase the size of the chamber.

[0009] In view of the above, an object of the present invention is to provide a shutter device and a film-forming device that are capable of forming a film with excellent coverage on each fine hole and trench with a high aspect ratio formed in a substrate without being affected by sputtered particles that accumulate during ignition.

[0010] To solve the above-mentioned problems, an aspect of the present invention employs the following configuration. A shutter device according to one aspect of the present invention is a shutter device provided in a film formation apparatus that forms a coating on the surface of a workpiece by sputtering. The shutter device includes a housing having an opening, multiple shutter plates each having a base end and a tip end and disposed within the opening, and multiple drive units each connecting the base end to the housing, corresponding one-to-one to the multiple shutter plates, and configured to change the posture of each of the multiple shutter plates. At least a portion of the opening is a passage area through which sputtered particles emitted from a target pass. The multiple drive units are configured to change the multiple shutter plates between a closed state in which the multiple shutter plates are disposed to block at least the passage area of ​​the sputtered particles, a parallel state in which some of the multiple shutter plates are disposed in the passage area of ​​the sputtered particles while the flight directions of the sputtered particles are parallel, or an open state in which the multiple shutter plates are retracted from the passage area of ​​the sputtered particles. In a shutter device according to one aspect of the present invention, when a direction from the center of the opening toward the housing is defined as a radial direction, the drive unit may include a rotary drive shaft whose axial direction is oriented in the same direction as the radial direction and which rotates the shutter plate, and an opening / closing mechanism which moves the tip of the shutter plate toward or away from the housing. The rotary drive shaft may be configured to change the attitude of the shutter plate between the closed state and the parallelized state. The opening / closing mechanism may be configured to change the attitude of the shutter plate between the parallelized state and the open state. In the shutter device according to one aspect of the present invention, the shutter plate may have a pair of long sides that approach each other in a direction from the base end toward the tip end. The shape of the shutter plate may be tapered from the base end toward the tip end. In the shutter device according to one aspect of the present invention, a portion of the shutter plate may be a flat, plate-like portion. The flat portion may be a portion that overlaps at least the passage area of ​​the sputtered particles in the parallelized state.In a shutter device according to one aspect of the present invention, the long side of the shutter plate may have a flange. The flange may close a gap between the long side and a long side of another shutter plate adjacent to the shutter plate when in the closed state. A film formation apparatus according to one aspect of the present invention is a film formation apparatus that forms a coating on a surface of a workpiece by sputtering. The film formation apparatus includes: a chamber that houses the workpiece and a target that is a base material for the coating, arranged to face each other; an exhaust unit that reduces the pressure inside the chamber; a magnetic field generation unit that generates a magnetic field in front of the sputtering surface of the target; a power supply that applies a voltage to the target; a gas introduction unit that introduces a sputtering gas into the chamber; and a shutter device that is arranged between the target and the workpiece. The shutter device is the shutter device according to the above aspect.

[0011] A shutter device according to an aspect of the present invention includes a drive unit capable of changing the position of multiple shutter plates arranged inside an opening. The drive unit can change the position of the shutter plates to a closed state that blocks the passage area of ​​sputtered particles, a parallel state that parallels the flight direction of sputtered particles, or an open state that retracts the shutter plates from the passage area of ​​sputtered particles. In the closed state, sputtered particles do not adhere to the workpiece during ignition. In the parallel state, the shutter plates function as collimators for the sputtered particles, allowing for the formation of a coating with high coverage on holes or trenches with a large aspect ratio. In the open state, the number of sputtered particles passing through the shutter device increases, improving the film formation rate. This allows for the formation of a film with excellent coverage on each fine hole and trench with a high aspect ratio formed in the workpiece without being affected by sputtered particles deposited during ignition.

[0012] In addition, in the shutter device according to this aspect of the present invention, the drive unit includes a rotary drive shaft and an opening / closing mechanism. The rotary drive shaft can change the position of the shutter plate between a closed state and a parallel state within the opening. The opening / closing mechanism can also change the position of the shutter plate between the parallel state and an open state. This eliminates the need to move the shutter plate out of the opening, allowing the shutter device to be made smaller.

[0013] In addition, in the shutter device according to the present invention, the shutter plate has a pair of long sides that approach each other in the direction from the base end toward the tip end. Furthermore, the shape of the shutter plate is tapered from the base end toward the tip end. Therefore, inside the opening, the position of the two adjacent shutter plates can be changed by a drive unit connected to the base end without interfering with each other.

[0014] In addition, in the shutter device according to this aspect of the present invention, a portion of the shutter plate is a flat, plate-like flat portion. The flat portion is a portion that overlaps at least the area through which sputtered particles pass when in a collimated state. This allows the shutter plate to function as a collimator. A coating with superior coverage can be formed on each fine hole and trench with a high aspect ratio formed in the workpiece.

[0015] In addition, in the shutter device according to this aspect of the present invention, the long side of the shutter plate has a flange portion. When the shutter plate is closed, the flange portion closes the gap between the long side and the long side of another shutter plate adjacent to the shutter plate. This prevents sputtered particles from leaking through the gap in the shutter plate, and reliably prevents sputtered particles from accumulating on the workpiece during ignition.

[0016] According to the film forming apparatus of the present invention, since it is equipped with a shutter device according to an aspect of the present invention, it is possible to form a film with excellent coverage on each fine hole and trench having a high aspect ratio formed in the workpiece without being affected by sputtered particles that accumulate during ignition.

[0017] FIG. 1 is a cross-sectional schematic side view of a film forming apparatus according to a first embodiment of the present invention. FIG. 2 is a plan view schematic showing a shutter device according to a first embodiment of the present invention. FIG. 3A is a perspective view schematic showing an example of a shutter plate provided in the shutter device according to a first embodiment of the present invention, as viewed from the target side. FIG. 3B is a perspective view schematic showing an example of a shutter plate provided in the shutter device according to a first embodiment of the present invention, as viewed from the workpiece side. FIG. 4A is a diagram illustrating the operation of a drive unit provided in the shutter device according to a first embodiment of the present invention, as viewed from the vertical direction, showing a state in which the shutter plate is open (parallelized state). FIG. 4B is a diagram illustrating the operation of a drive unit provided in the shutter device according to a first embodiment of the present invention, as viewed from the vertical direction, showing a state in which the shutter plate is closed (blocked state). FIG. 5A is a diagram illustrating the operation of a drive unit provided in the shutter device according to a first embodiment of the present invention, as viewed from the vertical direction, showing a state in which the shutter plate is retracted (parallelized state). FIG. 5B is a diagram explaining the operation of the drive unit provided in the shutter device according to the first embodiment of the present invention, and is a schematic diagram showing a state in which the shutter plate approaches the housing of the shutter device (open state) as viewed from the vertical direction. FIG. 6A is a diagram explaining the operation of the shutter device according to the first embodiment of the present invention, and is a schematic plan view showing a closed state. FIG. 6B is a diagram explaining the operation of the shutter device according to the first embodiment of the present invention, and is a schematic side view showing the closed state. FIG. 7A is a diagram explaining the operation of the shutter device according to the first embodiment of the present invention, and is a schematic plan view showing a parallelized state. FIG. 7B is a diagram explaining the operation of the shutter device according to the first embodiment of the present invention, and is a schematic side view showing the parallelized state. FIG. 8 is a diagram explaining the operation of the shutter device according to the first embodiment of the present invention, and is a schematic plan view showing an open state. A cross-sectional schematic diagram of a film formation apparatus according to a second embodiment of the present invention, as seen from the side. A cross-sectional schematic diagram of a film formation apparatus according to a third embodiment of the present invention, as seen from the side. A cross-sectional schematic diagram of a film formation apparatus according to a fourth embodiment of the present invention, as seen from the side.

[0018] In describing embodiments of the present invention, the ceiling side of a chamber constituting a film forming apparatus may be referred to as "top," "upper side," or "upper," and the bottom side of the chamber may be referred to as "bottom," "lower side," or "below." Regarding the definitions of directions, the circumferential direction of a circular housing constituting a shutter device may be simply referred to as the "circumferential direction." The radial direction of a circular housing may be simply referred to as the "radial direction." Furthermore, the direction from the center of the opening of the housing toward the outside of the housing may be simply referred to as the "radial direction." In the drawings describing embodiments of the present invention, symbols X, Y, Z, X1, and Y1 are shown. Symbol Z is a direction perpendicular to the surface on which the film forming apparatus is installed (Z direction), e.g., the vertical direction. In other words, the vertical direction is the direction from the ceiling to the bottom of the chamber. Symbol X is a direction parallel to the surface on which the film forming apparatus is installed (X direction) and perpendicular to the Z direction. Symbol Y is a direction parallel to the surface on which the film forming apparatus is installed (Y direction) and perpendicular to the Z direction. The X direction and the Y direction are perpendicular to each other. The X direction and the Y direction correspond to radial directions. In the description referring to FIGS. 4A, 4B, 4A, and 5B, the symbols X1 and Y1 are used. The symbol X1 is a direction parallel to the surface on which the film forming apparatus is installed (the X1 direction) and perpendicular to the Z direction. The symbol Y1 is a direction parallel to the surface on which the film forming apparatus is installed (the Y1 direction) and perpendicular to the Z direction. The X1 direction and the Y1 direction are perpendicular to each other. The X1 direction is a direction in which a rotary drive shaft constituting the shutter device extends. The X1 direction is used to describe the operation of the shutter device according to the embodiment, and the relationship between the X1 direction and the X direction is not particularly limited. For example, the X1 direction may be inclined with respect to the X direction or may be parallel to the X direction. When the X1 direction is inclined with respect to the X direction, the inclination angle between the X1 direction and the X direction is not limited. The X1 direction may or may not coincide with the radial direction.

[0019] In the following description, ordinal numbers such as "first" and "second" may be used. These ordinal numbers do not indicate the number of components described by the ordinal numbers. Ordinal numbers may be used to indicate that each of multiple components is a separate component. For example, of two adjacent shutter plates, one shutter plate 23 may be referred to as the first shutter plate, and the other shutter plate may be referred to as the second shutter plate. Alternatively, each of multiple shutter plates arranged in the circumferential direction may be referred to as the "first shutter plate," the "second shutter plate," ..., the "Nth shutter plate." In this case, N is a natural number equal to or greater than 2. In the embodiment, as an example, the number of multiple shutter plates is 8 (N=8).

[0020] The term "opposite" indicates the positional relationship between two components. This positional relationship not only means that the two components are facing each other, but also means that another component is interposed between the two components. The same interpretation applies to the terms "provided," "disposed," and "connected."

[0021] First Embodiment A film forming apparatus 1 and a shutter device 21 according to a first embodiment of the present invention will now be described. As shown in FIG. 1 , the film forming apparatus 1 is an apparatus that forms a coating by a sputtering method. The film forming apparatus 1 is an apparatus that uses a DC magnetron sputtering method. The film forming apparatus 1 is also a deposit-down type sputtering apparatus. The film forming apparatus 1 includes a chamber 2. A vacuum atmosphere can be generated in the internal space of the chamber 2. The chamber 2 accommodates a substrate W (object to be processed) and a target 3. A cathode unit C is attached to the ceiling of the chamber 2.

[0022] The cathode unit C includes a target 3. The target 3 is attached to a holder 5. The cathode unit C further includes a built-in magnetic field generator (not shown) that generates a tunnel-shaped magnetic field in front of the sputtering surface (lower surface) 3a of the target 3. The target 3 is a base material for a coating to be formed on a substrate W (object to be processed). The target 3 is made of a material, such as Cu, Ti, Al, or Ta, appropriately selected depending on the composition of the thin film to be formed on the substrate W (object to be processed). The shape of the target 3 corresponds to the shape of the substrate W to be processed. For example, the target 3 is fabricated by a known method to have a predetermined shape (e.g., circular in plan view) so that the area of ​​the sputtering surface 3a is larger than the surface area of ​​the substrate W. The target 3 is also electrically connected to a known DC power supply (sputtering power supply) (not shown). This allows a predetermined negative potential (voltage) to be applied to the target 3.

[0023] The magnetic field generating unit (not shown) built into the cathode unit C is disposed on the surface (upper surface) opposite the sputtering surface 3a of the target 3. The magnetic field generating unit includes a yoke (not shown) and multiple magnets (not shown). The yoke is disposed parallel to the target 3. The multiple magnets are disposed on the lower surface of the yoke. The multiple magnets are disposed so that the polarities of the magnet surfaces facing the target 3 are different from each other. The shape and number of magnets are appropriately selected depending on the magnetic field to be formed in front of the target 3, from the viewpoints of improving discharge stability and target utilization efficiency. For example, thin-plate or rod-shaped magnets may be used, or multiple magnets having such shapes may be appropriately combined. Furthermore, the magnetic field generating unit may be configured to reciprocate or rotate behind the target 3.

[0024] A stage 10 facing the target 3 is disposed at the bottom of the chamber 2. The stage 10 is configured to determine the position of the substrate W and to hold the substrate W. A gas pipe (gas inlet) (not shown) for introducing a sputtering gas such as argon gas is connected to a sidewall of the chamber 2. The other end of the gas pipe is connected to a gas source via a mass flow controller (not shown). An exhaust pipe 12a is also connected to the chamber 2. The exhaust pipe 12a leads to an exhaust unit (vacuum exhaust unit, vacuum exhaust device) (not shown) including a turbomolecular pump, a rotary pump, or the like. The exhaust unit reduces the pressure inside the chamber 2.

[0025] The shutter device 21 is disposed between the substrate W and the target 3. As shown in FIG. 2 , the shutter device 21 includes a housing 22, multiple shutter plates 23, and multiple drive units 24. In other words, the shutter device 21 can be referred to as a shutter mechanism. The housing 22 has an opening 22a. The multiple shutter plates 23 are disposed inside the opening 22a. The multiple drive units 24 correspond one-to-one to the multiple shutter plates 23. One of the multiple shutter plates 23 connects the housing 22 to one of the multiple shutter plates 23. The multiple drive units 24 are configured to change the posture of the multiple shutter plates 23 between a closed state, a parallel state, or an open state. In other words, when one drive unit 24 changes the posture of one shutter plate 23, the multiple drive units 24 change the posture of the multiple shutter plates 23 as a whole. Each of the multiple drive units 24 is controlled by a control device (not shown). The control device includes, for example, a processing unit, a memory unit, a communication unit, etc. In the control device, the processing unit may process information based on a program stored in the storage unit, or the processing unit may process information based on information input to the communication unit from an external device of the control device. The control device provides a drive signal according to the result of calculation in the processing unit to each of the multiple drive units 24, and the drive units 24 change the postures of the multiple shutter plates 23 based on the drive signal.

[0026] Here, the closed state is a state in which the shutter plate 23 is positioned so as to block at least the passage area PA of the sputtered particles. The closed state is the state shown in Figures 2, 6A, and 6B. The parallel state is a state in which a portion of the shutter plate 23 is positioned in the passage area PA of the sputtered particles while the flight direction of the sputtered particles is parallel. The parallel state is the state shown in Figures 7A and 7B. Moreover, the open state is a state in which the shutter plate 23 is retracted from the passage area PA of the sputtered particles. The open state is the state shown in Figure 8. The passage area PA of the sputtered particles will be described later.

[0027] As shown in FIGS. 1 and 2 , the housing 22 has an annular appearance. The housing 22 has an opening 22a that communicates with a space (first space) where the target 3 is exposed and a space (second space) where the substrate W is exposed. In other words, the opening 22a penetrates the housing 22. At least a portion of the opening 22a is a passing area PA through which sputtered particles emitted from the target pass. The passing area PA is the inner area indicated by the dashed-dotted line in FIG. 2 . Of the sputtered particles emitted from the sputtering particles, those that pass through the passing area PA have a relatively high probability of reaching the substrate W (object to be processed) compared to other sputtered particles. Furthermore, sputtered particles emitted from the sputtering particles may pass through an area outside the passing area PA. However, sputtered particles that pass through the passing area PA have a lower probability of reaching the substrate W (object to be processed) compared to sputtered particles that pass through the passing area PA. The range of the passing area PA is determined by the size of the target 3, the size of the substrate W (object to be processed), the distance between the target 3 and the substrate W, and the like.

[0028] A drive mechanism (not shown) is housed inside the annular housing 22. The drive mechanism has a mechanism in which known mechanical elements are combined, and constitutes a drive unit 24.

[0029] 3A and 3B show perspective views of the shutter plate 23. FIG. 3A is a schematic perspective view of the shutter plate 23 as viewed from the target 3. FIG. 3B is a schematic perspective view as viewed from the substrate W (processing object). The shutter plate 23 is plate-shaped. The shutter plate 23 has a base end 231, a tip end 232, and a pair of long sides 233. The pair of long sides 233 are shaped to approach each other in the direction from the base end 231 toward the tip end 232. In other words, since the multiple shutter plates 23 shown in FIG. 2 are arranged in the circumferential direction of the circular housing 22, the pair of long sides 233 are formed to approach each other in the radial direction of the housing 22. The pair of long sides 233 correspond to two ends of the shutter plate 23 in the circumferential direction of the housing 22. The overall shape of the shutter plate 23 is tapered from the base end 231 to the tip end 232. In other words, the width of the shutter plate 23 in the circumferential direction of the housing 22 gradually decreases in the radial direction from the base end 231 to the tip end 232. The shape of the base end 231 is a substantially arc shape when the shutter plate 23 is viewed in a plan view. The shape of this base end 231 corresponds to the shape of the opening 22a of the housing 22. The shape of the tip end 232 is an acute angle. When the shutter plate 23 is in the closed state, the tip end 232 is located at approximately the center O of the opening 22a.

[0030] The shutter plate 23 has a curved surface portion 234 and a flat portion 235. The curved surface portion 234 is located closer to the base end portion 231 than the tip end portion 232. The flat portion 235 is located closer to the tip end portion 232 than the base end portion 231. The flat portion 235 has a flat shape. The flat portion 235 is a portion that overlaps with the passage area PA of sputtered particles when the shutter plate 23 is in a parallel position. A boundary portion is located between the curved surface portion 234 and the flat portion 235. The distance between the tip end portion 232 and the boundary portion in the radial direction corresponds to the size of the passage area PA in the radial direction. The boundary portion is a boundary line that extends in the radial direction like an arc. The curved surface portion 234 is formed so as to be inclined from the boundary line toward the flat portion 235. The curved surface portion 234 may also be referred to as a tapered surface. As shown in Fig. 3B , non-through holes that do not penetrate the shutter plate 23 are formed on the surface of the flat portion 235 facing the substrate W. These non-through holes are provided to reduce the weight of the shutter plate 23, and can also be referred to as lightweight portions. In the example shown in Fig. 3B , the number of non-through holes is three, but the number of non-through holes is not limited. If the shutter plate 23 is sufficiently lightweight or if it is necessary to reduce the processing cost of the shutter plate 23, it is not necessary to provide non-through holes.

[0031] The long side portion 233 of the flat portion 235 of the shutter plate 23 has a flange portion 236. The flange portion 236 is provided to close the gap between the long side portion 233 of the shutter plate 23 (first shutter plate) and the long side portion 233 of another adjacent shutter plate 23 (second shutter plate) in the closed state.

[0032] 3A and 3B, a plate-shaped arm portion 241 is attached to the base end portion 231 of the shutter plate 23. The arm portion 241 constitutes part of the drive unit 24. In FIGS. 3A and 3B, the arm portion 241 is attached to an end portion (one end side) of the base end portion 231 in the circumferential direction. The position at which the arm portion 241 is provided is not limited to the structure shown in FIGS. 3A and 3B. The arm portion 241 may be located in the center of the base end portion 231. The arm portion 241 may be located on the opposite side of the base end portion 231 from the position shown in FIGS. 3A and 3B.

[0033] Next, the drive unit 24 will be described. As shown in FIG. 2 , the drive unit 24 connects the base end 231 of each shutter plate 23 to the housing 22. The drive unit 24 drives the shutter plate 23. The drive unit 24 is configured to change the attitude of the shutter plate 23. As described above, the drive unit 24 is configured to change the attitude of the shutter plate 23 to a closed state, a parallel state, or an open state. The drive unit 24 has a drive mechanism (not shown). The drive mechanism has, for example, a rotation mechanism that rotates the shutter plate 23 around a rotation axis, and a movement mechanism that moves the rotation axis. Examples of the rotation mechanism and the movement mechanism include a cylinder linear motion mechanism, a rack and pinion mechanism, a crank mechanism, a gear mechanism, a spring mechanism, a ball screw, a guide rail, etc.

[0034] The drive unit 24 has a rotation axis. The rotation axis extends in the radial direction. In other words, the rotation axis extends from the base end 231 to the tip end 232 of the shutter plate 23. The drive unit 24 can rotate the shutter plate 23 around the rotation axis by rotating the rotation axis. Note that the structure of the drive unit 24 is not particularly limited as long as it has a function of changing the direction from the base end 231 to the tip end 232 of the shutter plate 23 relative to the housing 22. More specifically, as an example, it is possible that the direction from the base end 231 to the tip end 232 of the shutter plate 23 approximately coincides with the radial direction from the center O of the opening 22a toward the housing 22. In this case, it is only necessary to have a function to rotate the shutter plate 23 by rotating the rotation shaft so that the direction from the base end 231 to the tip end 232 of the shutter plate 23 is changed from a state in which the shutter plate 23 is directed from the base end 231 to the tip end 232 of the shutter plate 23 toward the center O of the opening 22a to a state in which the shutter plate 23 is directed along the circumferential direction of the housing 22. Note that the extension direction of the rotation shaft does not have to coincide with the radial direction. As long as the drive unit 24 can operate, the extension direction of the rotation shaft is not limited.

[0035] Next, the drive unit 24 will be described with reference to FIGS. 4A, 4B, 4A, and 5B. The drive unit 24 preferably includes a rotary drive shaft 242 and an opening / closing mechanism 25. In FIGS. 4A, 4B, 4A, and 5B, the X1 and Y1 directions are used to explain an example of the operation of the drive unit 24, but the X1 and Y1 directions do not limit the attitude or position of the shutter plate 23. The dotted line indicated by the reference numeral 22 conveniently indicates the housing 22 of the shutter device 21. This dotted line is shown to facilitate understanding of the relationship between the housing 22 and the drive unit 24 in the X1, Y1, and Z directions. For example, the axial direction of the rotary drive shaft 242 is the same as the radial direction of the opening 22a. That is, the rotary drive shaft 242 extends in the X1 direction. The rotary drive shaft 242 is configured to rotate the shutter plate 23. That is, the rotary drive shaft 242 is configured to rotate the shutter plate 23 around the X1 direction. The opening / closing mechanism 25 is configured to move the tip 232 of the shutter plate 23 toward or away from the housing 22. That is, the opening / closing mechanism 25 is configured to move the shutter plate 23 in a plane parallel to the X1 direction and the Y1 direction. In other words, the opening / closing mechanism 25 is configured to rotate the shutter plate 23 around an axis parallel to the Z direction.

[0036] The rotary drive shaft 242 protrudes from the housing 22 toward the center of the opening 22a. The rotary drive shaft 242 is rotatable by a drive mechanism (not shown) built into the housing 22. The rotary drive shaft 242 is attached to the base end 231 of the shutter plate 23 via a first joint portion 251 and an arm portion 241. The rotary drive shaft 242 is configured to change the posture of the shutter plate 23 between a closed state and a parallel state.

[0037] The opening / closing mechanism 25 includes an arm 241, a rotary drive shaft 242, a first joint 251, a second joint 252, and an opening / closing drive shaft 253. The arm 241 is attached to the base end 231 of the shutter plate 23. The rotary drive shaft 242 has the configuration described above. The first joint 251 is disposed between the arm 241 and the rotary drive shaft 242. The first joint 251 is attached between the rotary drive shaft 242 and the arm 241. The first joint 251 can tilt the extension direction of the arm 241 relative to the extension direction of the rotary drive shaft 242. The first joint 251 is, for example, a hinge having an axis parallel to the Z direction. The second joint 252 is attached between the opening / closing drive shaft 253 and the arm 241. The second joint 252 can tilt the extension direction of the arm 241 relative to the extension direction of the opening / closing drive shaft 253. The second joint 252 is, for example, a hinge having an axis parallel to the Z direction. The opening / closing drive shaft 253 is disposed so as to be substantially parallel to the rotation drive shaft 242. In other words, the opening / closing drive shaft 253 extends in the X1 direction. The opening / closing drive shaft 253 is connected to a drive mechanism (not shown) built into the housing 22. When driven by the drive mechanism, the opening / closing drive shaft 253 advances and retreats along the longitudinal direction (X1 direction) of the opening / closing drive shaft 253. The opening / closing drive shaft 253 is configured to move linearly, for example, in a direction parallel to the radial direction. The opening / closing mechanism 25 is configured to change the attitude of the shutter plate 23 between a parallel state and an open state. Examples of the structure of the drive mechanism that operates the opening / closing drive shaft 253 include a cylinder linear motion mechanism, a rack and pinion mechanism, a crank mechanism, a gear mechanism, a spring mechanism, a ball screw, a guide rail, etc. In such an opening / closing mechanism 25, the opening / closing drive shaft 253 moves relative to the rotation drive shaft 242 in the longitudinal direction of the opening / closing drive shaft 253, whereby the arm portion 241 tilts with respect to the rotation drive shaft 242 in the rotation direction around the first joint portion 251, and the arm portion 241 tilts with respect to the opening / closing drive shaft 253 in the rotation direction around the second joint portion 252. In this way, the opening / closing mechanism 25 is configured to move the shutter plate 23 closer to or away from the housing 22.

[0038] The operation of the drive unit 24 will be described. As shown in Figures 4A and 4B, when the rotary drive shaft 242 is rotated in the X1 direction, the shutter plate 23 rotates around the rotary drive shaft 242 as an axis, and the attitude of the shutter plate 23 changes.

[0039] 5A and 5B , when the opening / closing drive shaft 253 provided in the opening / closing mechanism 25 is advanced or retreated in the X1 direction, the orientation of the arm 241 changes with the first joint 251 as the rotation axis. That is, when the opening / closing drive shaft 253 moves in the X1 direction, the orientation of the arm 241 changes from an orientation facing the X1 direction to an orientation facing the Y1 direction. Accordingly, the orientation of the shutter plate 23 also changes from an orientation facing the X1 direction ( FIG. 5A ) to an orientation facing the Y1 direction ( FIG. 5B ). Conversely, when the opening / closing drive shaft 253 moves in the direction opposite the X1 direction, the orientation of the arm 241 changes from an orientation facing the Y1 direction to an orientation facing the X1 direction. Accordingly, the orientation of the shutter plate 23 also changes from an orientation facing the Y1 direction ( FIG. 5B ) to an orientation facing the X1 direction ( FIG. 5A ).

[0040] Since the operation of the drive unit 24 can be realized as shown in Figures 4A, 4B, 4A, and 5B, the postures of the multiple shutter plates 23 can be set to a closed state, a parallel state, and an open state as shown in Figures 6A to 8.

[0041] 6A and 6B , the direction from the base end 231 to the tip end 232 of each shutter plate 23 faces the center O of the opening 22a. The tip end 232 of each shutter plate 23 is located at the center O of the opening 22a. Furthermore, the orientation of each of the multiple shutter plates 23 is aligned so that each of the multiple shutter plates 23 blocks the opening 22a. With respect to two adjacent shutter plates 23 among the multiple shutter plates 23, the long side 233 (first long side) of one shutter plate 23 (first shutter plate) is close to the long side 233 (second long side) of the other shutter plate 23 (second shutter plate). However, to prevent particle generation, the long side 233 of the two adjacent shutter plates 23 do not contact each other and are arranged with a small gap between them. In this case, in order to prevent sputtered particles from leaking out to the object to be processed through the gap between the two long side portions 233, the flange portion 236 provided on the long side portion 233 is configured to overlap the other long side portion 233. This blocks the gap while keeping the long side portions 233 out of contact with each other.

[0042] When the rotation drive shaft 242 is operated to rotate the shutter plates 23 from this closed state, the parallelized state shown in Figures 7A and 7B is achieved. In the parallelized state, a portion (flat portion 235) of each shutter plate 23 is located in the passage area PA of the sputtered particles. In this position, the long side portions 233 of the shutter plates 23 face the target 3 and the workpiece W. This allows the shutter plates 23 to function as collimators, and the flight directions of the sputtered particles are aligned parallel as they pass through the shutter plates 23.

[0043] Furthermore, when the opening / closing mechanism 25 is operated to tilt the tip 232 of the shutter plate 23 toward the housing 22 from the parallel state, the shutter plate 23 enters an open state as shown in Fig. 8. In the open state, the direction from the base end 231 of the shutter plate 23 toward the tip 232 is aligned with the circumferential direction of the opening 22a. Therefore, the tip 232 of the shutter plate 23 approaches the housing 22. This causes the shutter plate 23 to retreat from the area PA through which sputtered particles pass through the opening 22a.

[0044] Next, a description will be given of film formation using the above-described film formation apparatus 1. First, the vacuum exhaust unit is operated to reduce the vacuum level in the chamber 2 to a predetermined vacuum level (for example, 10 －５ The internal space of the chamber 2 is evacuated until the pressure reaches a predetermined value (a pressure in the order of Pa). Then, after the pressure in the chamber 2 reaches a predetermined value, the substrate W is set on the stage 10. Furthermore, the shutter plate 23 of the shutter device 21 is closed as shown in FIGS. 6A and 6B . A gas (sputtering gas) is introduced into the internal space of the chamber 2 at a predetermined flow rate. In this state, a predetermined negative potential is applied (power is applied) to the target 3 from the DC power supply to generate a plasma atmosphere in the chamber 2. In this case, the magnetic field from the magnetic field generating unit captures electrons ionized in front of the sputtering surface 3 a and secondary electrons generated by sputtering, generating high-density plasma in front of the sputtering surface 3 a.

[0045] Argon ions in the plasma collide with the sputtering surface 3a, sputtering the sputtering surface 3a, and sputter atoms and sputter ions (sputter particles) are scattered from the sputtering surface 3a toward the substrate W. At this stage, the shutter device 21 is in a closed state, so the sputter particles only adhere to the shutter plate 23 and do not reach the substrate W.

[0046] After the initial stage of sputtering is completed and the plasma is stabilized, the rotary drive shaft 242 of the drive unit 24 is operated to transition from the closed state to the parallelized state. This exposes the substrate W to the target 3. The shutter plate 23 also functions as a collimator. This allows the sputtered particles to reach the substrate W and initiate film formation. In particular, when a Cu target is used, self-sustained discharge is possible. Therefore, after ignition by introducing the sputtering gas, it is possible to stop the introduction of the sputtering gas into the internal space of the chamber 2, wait until the plasma is stabilized, and then transition the shutter device 21 from the closed state to the parallelized state to initiate film formation on the substrate W. When film formation is performed in the parallelized state, the flight direction of the sputtered particles is parallelized by the flat portion 235 of the shutter plate 23. This allows the sputtered particles to reach the interior of holes and trenches with high aspect ratios provided in the substrate W, thereby increasing the film coverage.

[0047] Furthermore, when the initial stage of sputtering is completed and the plasma is stabilized, the rotary drive shaft 242 of the drive unit 24 and the opening / closing mechanism 25 may be operated to transition from the closed state to the parallelized state and then to the open state. This exposes the substrate W to the target 3. This allows the sputtered particles to reach the substrate W and initiate film formation. When film formation is performed in the open state, although the flight direction of the sputtered particles becomes random, the sputtered particles are more likely to reach the substrate W, making it possible to increase the film formation rate.

[0048] As described above, the shutter device 21 according to the first embodiment includes a drive unit 24 that can change the attitude of the multiple shutter plates 23 arranged within the opening 22a. The drive unit 24 is configured to change the attitude of the shutter plates 23 between a closed state that blocks the passage area PA of sputtered particles, a parallel state that parallels the flight direction of the sputtered particles, and an open state that retracts the sputtered particles from the passage area PA. In the closed state, sputtered particles do not adhere to the substrate W during ignition. In the parallel state, the shutter plates 23 function as collimators for the sputtered particles, thereby enabling the formation of a coating with high coverage on holes or trenches with a large aspect ratio. In the open state, the number of sputtered particles passing through the shutter device 21 increases, thereby improving the film formation rate. This allows for the formation of a film with excellent coverage on each fine hole and trench with a high aspect ratio formed in the workpiece without being affected by sputtered particles deposited during ignition.

[0049] Furthermore, in the shutter device 21 according to the first embodiment, the drive unit 24 includes a rotary drive shaft 242 and an opening / closing mechanism 25. Within the opening 22a, the orientation of the shutter plate 23 can be changed between a closed state and a parallel state by the rotary drive shaft 242. Furthermore, the orientation of the shutter plate 23 can be changed between a parallel state and an open state by the opening / closing mechanism 25. This eliminates the need to move the shutter plate 23 out of the opening 22a, allowing the shutter device 21 to be made more compact.

[0050] Furthermore, according to the shutter device 21 according to the first embodiment, the shutter plate 23 has a base end 231, a tip end 232, and a pair of adjacent long sides 233. Furthermore, the shape of the shutter plate 23 is tapered in the direction from the base end 231 to the tip end 232. Therefore, inside the opening 22a, the drive unit 24 connected to the base end 231 can change the position of the shutter plates 23 without causing interference between two adjacent shutter plates 23.

[0051] Furthermore, according to the shutter device 21 of the first embodiment, at least the portion of the shutter plate 23 that overlaps with the passage area PA of the sputtered particles in the collimated state is formed as a flat plate. This allows the shutter plate 23 to function as a collimator. This allows a coating with better coverage to be formed on each of the fine holes and trenches with a high aspect ratio formed in the substrate W (processing object).

[0052] Furthermore, according to the shutter device 21 of the first embodiment, a flange portion 236 is provided on the long side portion 233 of the shutter plate 23 to close the gap between the shutter plate 23 and another adjacent long side portion 233 when the shutter plate 23 is in the closed state. This prevents sputtered particles from leaking from the gap in the shutter plate 23, and makes it possible to reliably prevent deposition of sputtered particles on the substrate W (object to be processed) at the time of ignition.

[0053] According to the film forming apparatus 1 equipped with the shutter device 21 of the first embodiment, it is possible to form a film with excellent coverage on each fine hole and trench having a high aspect ratio formed in the substrate W without being affected by sputtered particles that accumulate during ignition.

[0054] <Modifications> Modifications of the attitude and orientation of the shutter device 21 will be described. When the shutter device 21 is in the closed state, the shutter device 21, which is composed of multiple shutter plates 23, has a substantially U-shape or cup-shape in the cross-sectional view shown in FIGS. 1 and 6B . The attitude and orientation of the shutter device 21 are not limited to the examples shown in FIGS. 1 and 6B . As a modification of the shutter device 21, the attitude and orientation of the shutter device 21 may be set so that the cross-sectional view has a substantially inverted U-shape or inverted cup-shape. In such a modification, FIG. 3A is a schematic perspective view of the shutter plate 23 as seen from the substrate W, and FIG. 3B is a schematic perspective view as seen from the target 3. This modification of the shutter device 21 can achieve the same effects as those described above. This modification can also be applied to other embodiments described later.

[0055] <Other Embodiments> In the shutter device 21 according to the first embodiment described above, the state of the shutter plate 23 is changed to a closed state, a parallel state, or an open state by driving a plurality of driving units 24. Apparatuses to which the shutter device 21 can be applied are not limited to the above-described film formation apparatus 1, and the shutter device 21 can also be applied to other film formation apparatuses described below. In Figures 9 to 11 described below, the same members as those in the first embodiment described above are assigned the same reference numerals, and their description will be omitted or simplified.

[0056] Second Embodiment Although the above-described film formation apparatus 1 is a deposition-down type sputtering apparatus, the shutter device 21 according to the embodiment of the present invention can also be applied to a deposition-up type sputtering apparatus. The film formation apparatus 1A shown in FIG. 9 is a deposition-up type sputtering apparatus. In the film formation apparatus 1A, a cathode unit C is provided at the bottom of a chamber 2. The cathode unit C includes a target 3. A stage 10 is provided at the ceiling of the chamber 2. The stage 10 holds a substrate W. A shutter device 21 is disposed between the substrate W and the target 3. The film formation apparatus 1A having this configuration uses the shutter device 21, as in the first embodiment described above, and changes the state of the shutter plate 23 to a closed state, a parallelized state, or an open state. This allows for film formation with excellent coverage in fine holes and trenches having a high aspect ratio formed in a processing object without being affected by sputtered particles deposited during ignition. Therefore, the same effects as those described in the first embodiment can be obtained.

[0057] Third Embodiment Although the above-described film formation apparatus 1 is an apparatus using a DC magnetron sputtering method, the shutter device 21 according to the embodiment of the present invention is not limited to magnetron sputtering film formation apparatuses and can also be applied to evaporation apparatuses. The film formation apparatus 1B shown in FIG. 10 is an evaporation apparatus. The film formation apparatus 1B includes an evaporation material 50, a crucible 51, and an electron gun 52. The evaporation material 50 and the crucible 51 constitute an evaporation source. The evaporation material 50, the crucible 51, and the electron gun 52 are disposed at the bottom of a chamber 2. The electron gun 52 generates an electron beam BM toward the crucible 51, thereby evaporating the evaporation material 50. The shutter device 21 is disposed between the substrate W and the evaporation material 50. In the film formation apparatus 1B having such a configuration, the evaporated evaporation material 50 reaches the substrate W via the shutter device 21. The evaporation material 50 is deposited on the surface of the substrate W, forming a thin film on the substrate W. The film forming apparatus 1B having this configuration uses a shutter device 21, as in the first embodiment described above, and changes the state of the shutter plate 23 to a closed state, a parallel state, or an open state. This allows film formation with excellent coverage to be performed on each fine hole and trench having a high aspect ratio formed in the processing target object without being affected by the deposition material 50 that accumulates on the substrate W when the deposition apparatus is ignited. Therefore, the same effects as those described in the first embodiment described above can be obtained.

[0058] Fourth Embodiment The shutter device 21 according to an embodiment of the present invention can also be applied to a CVD (Chemical Vapor Deposition) apparatus. The film formation apparatus 1C shown in FIG. 11 is a CVD apparatus. The film formation apparatus 1C includes a first material supply source 60, a second material supply source 61, a material supply path 62, and a shower head 63. The shower head 63 is disposed near the ceiling of the chamber 2. A stage 10 facing the shower head 63 is disposed at the bottom of the chamber 2. The first material supply source 60 and the second material supply source 61 supply source gases to the shower head 63 via the material supply path 62. The types of source gases in the first material supply source 60 and the second material supply source 61 are selected depending on the type of thin film to be formed on the substrate W. The shower head 63 applies energy to the source gases, causing a chemical reaction in the source gases released from the shower head 63. Here, "applying energy to the source gas to cause a chemical reaction" refers to applying energy such as heat, plasma, or light to the source gas to cause a chemical reaction. In this embodiment, plasma is generated between the shower head 63 and the substrate W, and the plasma causes a chemical reaction in the source gas. That is, the film forming apparatus 1C is a plasma CVD apparatus. The shutter device 21 is disposed between the substrate W and the shower head 63. With the film forming apparatus 1C having such a configuration, a chemical reaction occurs in the source gas released from the shower head 63, and the source gas reaches the substrate W via the shutter device 21. A reactant of the source gas is deposited on the surface of the substrate W, forming a thin film on the substrate W. The film forming apparatus 1C having such a configuration uses the shutter device 21, as in the first embodiment described above, and therefore the state of the shutter plate 23 is changeable between a closed state, a parallel state, and an open state. This allows deposition of a film with excellent coverage to each of the fine holes and trenches having a high aspect ratio formed in the workpiece without being affected by the deposition material 50 that accumulates on the substrate W when the CVD device is ignited, thereby achieving the same effects as those described in the first embodiment.In this embodiment, a plasma CVD apparatus including the shutter device 21 has been described. The shutter device 21 may be applied to other apparatuses besides plasma CVD apparatuses, such as a thermal CVD apparatus, a plasma CVD apparatus, an optical CVD apparatus, and an MOCVD (Metalorganic Chemical Vapor Deposition) apparatus. In such CVD apparatuses, the shutter device 21 is disposed at a position separated from the film formation surface of the substrate, that is, the shutter device 21 is disposed in a flow path along which the source gas flows toward the film formation surface of the substrate.

[0059] While preferred embodiments of the present invention have been described and illustrated above, it should be understood that these are illustrative of the present invention and should not be considered as limiting. Additions, omissions, substitutions, and other modifications can be made without departing from the scope of the present invention. Therefore, the present invention should not be considered as limited by the foregoing description.

[0060] 1, 1A, 1B, 1C...film forming apparatus, 2...chamber, 3...target, 21...shutter device, 22...housing, 22a...opening, 23...shutter plate, 24...driving unit, 25...opening / closing mechanism, 50...evaporation material, 51...crucible, 52...electron gun, 60...first material supply source, 61...second material supply source, 62...material supply path, 63...shower head, 231...base end, 232...tip, 233...long side, 235...flat portion, 236...flange portion, 242...rotation drive shaft, O...center of opening, PA...passing area, W...substrate (object to be processed).

Claims

1. A shutter device provided in a film forming apparatus which forms a coating on the surface of a workpiece by a sputtering method, comprising: a housing having an opening; a plurality of shutter plates, each having a base end and a tip end, arranged inside the opening; and a plurality of drive units, each connecting the base end to the housing and corresponding one-to-one with the plurality of shutter plates and configured to change the posture of each of the plurality of shutter plates, wherein at least a portion of the area of ​​the opening is a passage area through which sputtered particles emitted from a target pass, and the plurality of drive units are configured to change the state of the plurality of shutter plates to a closed state where they are arranged to at least block the passage area of ​​the sputtered particles, a parallel state where they are arranged so that the flight directions of the sputtered particles are parallel while a portion of the plurality of shutter plates are arranged in the passage area of ​​the sputtered particles, or an open state where they are moved away from the passage area of ​​the sputtered particles.

2. A shutter device as described in claim 1, wherein, when the direction from the center of the opening toward the housing is defined as a radial direction, the drive unit comprises: a rotary drive shaft whose axial direction faces the same direction as the radial direction and which rotates the shutter plate; and an opening and closing mechanism which moves the tip of the shutter plate closer to the housing or away from the housing, wherein the rotary drive shaft is configured to change the position of the shutter plate between the closed state and the parallel state, and the opening and closing mechanism is configured to change the position of the shutter plate between the parallel state and the open state.

3. The shutter device as described in claim 1, wherein the shutter plate has a pair of long sides that approach each other in a direction from the base end to the tip end, and the shape of the shutter plate tapers from the base end to the tip end.

4. The shutter device according to claim 3, wherein a portion of the shutter plate is a flat, plate-like flat portion, and the flat portion overlaps at least the passage area of ​​the sputtered particles when in the parallelized state.

5. A shutter device as described in claim 4, wherein the long side portion of the shutter plate has a flange portion which, when in the closed state, closes the gap between the long side portion and a long side portion of another shutter plate adjacent to the shutter plate.

6. A film formation apparatus for forming a coating on a surface of a workpiece by a sputtering method, comprising: a chamber for accommodating the workpiece and a target which is a base material for the coating, the workpiece being arranged to face each other; an exhaust section for reducing the pressure inside the chamber; a magnetic field generating section for generating a magnetic field in front of the sputtering surface of the target; a power source for applying a voltage to the target; a gas inlet section for introducing a sputtering gas into the chamber; and a shutter device arranged between the target and the workpiece, the shutter device being a shutter device according to any one of claims 1 to 5.

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