JP2008081763A - Target assembly unit and sputtering apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a target assembly unit and a sputtering apparatus, capable of appropriately securing the cooling capacity of a target by a cooling plate when the sputtering apparatus is in operation (in evacuation) while attaining the efficient target changing work, prevention of in-plane thermal distortion of the target, re-using of a backing plate, and easy correspondence to wide erosion of the target, by attachably/detachably connecting the target to the cooling plate while suitable parts of the target serves as connection parts. <P>SOLUTION: The target assembly unit T comprises a target 10 for sputtering, and a cooling plate 11 which fixes the target 10 via a first connection means 19 and is supported by a casing 13 via a second connection means 15. The target 10 is elastically deformed along the surface of the cooling plate 11 based on the external force of the first connection means 19. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a target assembly unit and a sputtering apparatus, and more particularly to a technique for appropriately controlling the cooling capacity of a target by a cooling plate during operation of the sputtering apparatus.

  Sputtering techniques in which ions (for example, Ar ions) collide with a target in a vacuum to cause the target atoms to jump out and adhere to a substrate disposed opposite to the target are well known in the past. It is a fundamental technology used in the manufacturing process of semiconductor elements and LCDs.

  A copper back plate (hereinafter referred to as “backing plate”) that also serves as an electrode function and a cooling function of the target is usually provided on the back surface of the aluminum or chromium target used in the sputtering technique.

  By the way, since the degree of deformation of the backing plate has a significant effect on the dimensional accuracy of the target, various ideas have been conventionally made on the backing plate to suppress the deformation as much as possible.

  For example, in order to suppress the deformation of the backing plate based on the differential pressure between the atmospheric pressure on the back side of the backing plate and the vacuum pressure on the front side, a technique for pulling the center of the backing plate with a bolt in the direction against this differential pressure (See Patent Document 1).

  In addition, there is a technique that eliminates the cause of the deformation of the backing plate by eliminating the pressure difference that causes the deformation of the backing plate by making the back surface side of the backing plate the same as the surface side, thereby eliminating the pressure difference that causes the deformation of the backing plate (see Patent Document 2).

  In addition, there is a technique for suppressing deformation, cracking, and peeling of the target by providing a buffer layer between the target and the backing plate and soldering the target and the backing plate (see Patent Document 3).

  Furthermore, there is a technology for making the surface of the backing plate a concave curved surface in advance in anticipation of the amount of warping of the backing plate caused by the difference in thermal contraction rate between the backing plate and the target at the time of bonding and bonding (Patent Document). 4 and Patent Document 5).

  Note that the term “backing plate” is commonly used as a member that is bonded and bonded to the back surface of the target material by soldering or bonding, and is shipped (exchanged) integrally with the target material. The “plate” includes a plate member that is detachably fixed to the back surface of the target by screwing or the like.

As known literature examples describing the above-mentioned “backing plate” plate member that is screwed separately from the target, there are Patent Literature 6, Patent Literature 7, Patent Literature 8, and Patent Literature 9.
Japanese Patent No. 3390338 JP-A-7-331428 JP-A-61-250167 JP-A-6-128734 Japanese Patent No. 2573653 JP-A-7-109568 JP 2000-26962 A JP 2000-290772 A JP 2000-303171 A

  The inventor detachably connects the center portion of the target, which is a dead space for erosion, to the backing plate (cooling plate) for cooling the target, for example, by screwing, and fixes the peripheral portion of the backing plate to the support member. In this case, it is considered preferable to improve the efficiency of target replacement work, prevent in-plane thermal distortion of the target, reuse the backing plate, and facilitate wide erosion of the target.

  By the way, in this case, from the viewpoint of appropriately securing the cooling capacity of the target by the backing plate, how to control the deformation of the backing plate during the operation of the sputtering apparatus (during decompression in the vacuum chamber) Mechanism design guidelines are required. Therefore, first, in determining such a design guideline, whether or not to consider the buckling plate deformation suppressing technology described in Patent Documents 1 to 5 was examined.

  The peripheral structure of the target described in Patent Document 1 is disadvantageous for wide erosion of the target because the bolt penetrates the magnet and it is difficult to rotate or swing the magnet. Further, the peripheral structure of the target described in Patent Document 2 increases the internal volume to be evacuated, and is difficult to use in a batch-type apparatus that frequently releases the inside of the vacuum chamber to the atmosphere. There is also the problem of increased costs associated with installation. Therefore, the above-mentioned disadvantages are conspicuously lacking in the backing plate peripheral structures of Patent Document 1 and Patent Document 2.

  On the other hand, the techniques described in Patent Documents 3, 4 and 5 deal with inconveniences in the case where the target and the backing plate are bonded to each other with solder or the like before the target is mounted in the vacuum chamber. Therefore, these techniques cannot be directly applied to a method for controlling the deformation of the backing plate during the operation of the sputtering apparatus on the premise of a mechanism for detachably connecting the target to the backing plate.

  The present invention has been made in view of such circumstances, and by connecting the target detachably to the cooling plate with the appropriate place of the target as a connecting portion, the target replacement work efficiency is improved, the in-plane direction of the target Target assembly unit and sputtering that can appropriately secure the cooling capacity of the target by the cooling plate when the sputtering apparatus is operating (at the time of decompression) while preventing thermal strain, reusing the backing plate, and facilitating wide erosion of the target An object is to provide an apparatus.

  In order to solve the above-described problems, a target assembly unit according to the present invention includes a sputtering target, a cooling plate that is fixed to the target via first connection means and supported by the casing via second connection means. The target is elastically deformed along the surface of the cooling plate based on the external force of the first connecting means.

  Here, as an example of the deformation of the target, the surface of the cooling plate may be formed in a curved shape, and the target in a flat state may be elastically deformed into a curved shape.

  As another modification of the target, the surface of the cooling plate may be formed flat, and the curved target may be elastically deformed flat.

  Thereby, for example, even when the sputtering apparatus is in operation (at the time of depressurization), even if a differential pressure between negative pressure and atmospheric pressure is given to the back surface of the cooling plate, By returning the elastically deformed target, the adhesion between the target and the cooling plate can be maintained. Therefore, the cooling capacity (cooling efficiency) of the target by the cooling plate during operation of the sputtering apparatus is appropriately ensured.

  The first connecting means may be located at a substantially central portion in the width direction of the cooling plate and the target, and the second connecting means may be located at a peripheral portion of the cooling plate.

  Further, the shape of the surface of the cooling plate is determined by the bending of the cooling plate based on the load applied to the back surface of the cooling plate when the cooling plate is fixedly supported on the casing by the second connecting means. May be set to be flat.

  Accordingly, the target can be leveled during sputtering of the target, and adhesion between the back surface of the target and the surface of the backing plate can be appropriately maintained during operation of the sputtering apparatus.

  The cooling plate may be configured to be curved.

  The surface of the cooling plate may be cut into the curved shape.

  When the surface of the cooling plate is exposed to a reduced internal space, the load may be a distributed load due to a differential pressure between the pressure of the internal space and atmospheric pressure.

  Further, the sputtering apparatus according to the present invention is mounted on the wall of the vacuum chamber through an insulating member and a vacuum chamber having an internal space depressurized by a vacuum exhaust means, and the surface of the target and the cooling plate is attached to the surface of the target. It is an apparatus provided with the said target assembly unit arrange | positioned so that it may expose to the said interior space airtight, and the magnetic field generation | occurrence | production means arrange | positioned at the back surface side of the said cooling plate.

  According to the present invention, by connecting the target detachably to the cooling plate with the appropriate place of the target as a connecting portion, the target replacement work efficiency, the target in-plane thermal strain prevention, the backing plate reuse, and It is possible to obtain a target assembly unit and a sputtering apparatus that can appropriately ensure the cooling capacity of the target by the cooling plate when the sputtering apparatus is operating (at the time of decompression) while facilitating the wide erosion of the target.

  First, the inventor of the present invention verified whether or not the cooling capacity of the target was changed by the backing plate when the sputtering apparatus was in operation and when it was vented (when the atmosphere was opened). As a result, the following guidelines for designing the backing plate were obtained.

  This verification experiment is performed by the sputtering apparatus shown in FIG. 1 and FIG. 2, and the result obtained by this verification experiment is shown in FIG.

  FIG. 1 is a cross-sectional view of the periphery of a target assembly unit of a sputtering apparatus used for measuring the cooling ability of the target by a backing plate during operation and venting of the sputtering apparatus. FIG. 2 is a plan view of the back side of the target assembly unit shown in FIG.

  In the illustration of FIG. 1, for convenience, the short side direction (width direction) of the rectangular target 10 is the left-right direction, the long side direction (longitudinal direction) of the target 10 is the direction perpendicular to the paper surface, and the thickness of the target 10 The direction is the vertical direction.

  The sputtering apparatus 100 mainly has a vacuum chamber 40 having an internal space S whose pressure is reduced to an appropriate degree of vacuum by a vacuum pump V (evacuation means), and a wall hole 40a formed in the lower wall of the vacuum chamber 40. A target assembly unit T inserted so as to keep the internal space S to be depressurized, a magnet unit M (magnetic field generating means) disposed on the back side (atmosphere side) of the target assembly unit T, and a target assembly unit T The substrate assembly unit (not shown) holding the substrate (not shown) on which the target material is deposited and the target assembly unit T functioning as a target electrode are appropriately supplied with electric power for plasma discharge. Power supply means (not shown), and discharge gas supply means (not shown) for introducing a discharge gas (for example, Ar gas) into the vacuum chamber 40.

  As shown in FIG. 1, the target assembly unit T is disposed on a rectangular aluminum flat target 10 existing in the internal space S to be decompressed, and on the back surface of the target 10. A rectangular copper flat backing plate 11 (cooling plate) and an annular metal casing 13 that supports the peripheral edge of the backing plate 11.

  Here, due to the vacuum seal described later, the surface of the backing plate 11 (the contact surface with the target 10) is exposed to the reduced internal space S, and the back surface of the backing plate 11 (the side opposite to the contact surface). Surface) is exposed to the atmosphere. For this reason, the backing plate 11 when the sputtering apparatus 100 is operated (during decompression) inevitably has a reduced pressure in the inner space S on the front side of the backing plate 11 and an atmospheric pressure on the back side of the backing plate 11. The differential pressure between is given.

  A plurality of through holes are formed in the center of the target 10 in the width direction (left-right direction) along a center line L extending in the longitudinal direction of the target 10 (direction perpendicular to the paper surface of FIG. 1). Further, a portion facing the through hole is threaded along a center line L extending in the longitudinal direction of the backing plate 11 at the center in the width direction of the backing plate 11. Thus, the bolt 19 (for example, a hexagon socket head bolt; first connecting means) in which the center portion in the width direction of the target 10 and the center portion in the width direction of the backing plate 11 are fitted and screwed into the through holes is used. A plurality of points are connected at the center line L, and are fixedly fixed along the center line L. Therefore, thermal strain in the in-plane direction of the target (particularly the width direction of the target 10) can be prevented, and the target 10 can be easily removed from the backing plate 11 by releasing the connection of the bolt 19, so Increase efficiency.

  Here, the head of the bolt 19 is exposed to the internal space S. However, if there is a concern that the bolt 19 adversely affects the plasma discharge formation, the bolt 19 is retracted inside the target 10. This may be covered with a cap (not shown) made of the same aluminum material as the target 10.

  A plurality of through holes are formed in the peripheral portion of the backing plate 11. Further, the annular backing plate abutting surface 13a of the casing 13 is threaded at a portion facing the through hole. As a result, the peripheral edge of the backing plate 11 and the backing plate abutting surface 13a of the casing 13 are appropriately secured by the bolt 15 (for example, a hexagon socket head bolt; second connecting means) fitted and screwed into the through hole. Fixed. In addition, an annular elongated O-ring groove into which the O-ring 16 is fitted is formed on the backing plate abutting surface 13a of the casing 13 so as to be adjacent to the bolt 15, whereby the backing plate 11 and the casing by the bolt 15 are formed. The vacuum seal when fixing between 13 is made appropriately. Thus, in the indirect cooling sputtering apparatus 100 that mechanically connects the target 10 to the backing plate 11 that is cooled by an appropriate method (described later), a vacuum is applied between the backing plate 11 and the casing 13. Since the sealing is performed, there is an effect that the vacuum pressure does not directly act on the target 10 when the sputtering apparatus 100 is operated.

  The casing 13 includes a cylindrical portion 13b that extends downward from the backing plate contact surface 13a, and an annular flange portion 13c that extends outward from the vicinity of the lower end of the cylindrical portion 13b. When the target assembly unit T is inserted into the wall hole 40a, an annular insulating flange 23 whose inner peripheral surface is aligned with the wall hole 40a is sandwiched between the flange 13c and the lower wall of the vacuum chamber 40, so that both It will abut. As a result, the target assembly unit T is insulated from the grounded vacuum chamber 40, and the target assembly unit T is positioned in the vertical direction when the target assembly unit T is inserted into the wall hole 40a. In addition, on the insulating flange contact surface of the lower wall of the vacuum chamber 40 and the insulating flange contact surface of the flange portion 13c, annular elongated O-ring grooves into which the O-rings 17 and 18 are respectively fitted are formed. Vacuum sealing at the time of fixing between the casing 13 and the insulating flange 23 by a fixing means (not shown) or fixing between the vacuum chamber 40 and the insulating flange 23 is appropriately performed.

  Note that the inner surface of the lower wall of the vacuum chamber 40 (the surface opposite to the insulating flange contact surface) is located in the vicinity of the periphery of the target 10 and is in a grounded state so as to cover the peripheral edge of the backing plate 11. A metal shield plate 12 may be disposed. Thereby, abnormal discharge prevention at the time of plasma discharge by Ar gas on the target 10 and deposition contamination of the target material on the backing plate 11 are prevented.

  The magnet unit M has a rectangular ferromagnetic yoke 22 that is substantially the same shape as the target 10 in plan view (more precisely, a similar shape). Above the yoke 22, above the vicinity of the surface of the target 10. One rod-shaped central magnet 20 and two rod-shaped outer magnets 21 that create a tunnel-like leakage magnetic field B for confining plasma are arranged with their magnetic moments in opposite directions. For example, in this embodiment, the N pole side of the central magnet 20 faces the back surface of the target assembly unit T, while the S pole side of the outer magnet 21 faces the back surface of the target assembly unit T.

The target 10 is a thin film base material to be coated on the substrate. For the purpose of forming an electric field E that attracts ions (Ar ⁺ ) in the discharge plasma, the target 10 becomes a cathode from a DC constant power source (not shown). Constant power is supplied. The vacuum chamber 40 is connected to the anode side of the constant power source. In the process of sputtering the target 10, a large number of charged particles (Ar ⁺ and electrons) are formed near the surface of the target 10 due to Ar gas discharge (magnetron sputtering discharge) generated when the leakage magnetic field B and the electric field E are orthogonal to each other. ) Is formed.

The Ar ⁺ is attracted to the target 10 by a constant power electric field E applied to the target 10 from a constant power source. Thereby, the constituent atoms (in this case, aluminum atoms) of the target 10 are knocked out from the surface of the target 10 by the collision energy of Ar ⁺ , and the knocked-out aluminum atoms are deposited on the substrate. As a result, the target 10 is locally scraped and the erosion C of the target 10 progresses. However, in this embodiment, since the magnet unit M can be easily swung in the left-right direction, the erosion C can be widened, and the target 10 utilization efficiency can be improved.

  As shown in FIGS. 1 and 2, a cooling water guide plate 14 that forms a substantially U-shaped water jacket 14 a (double structure space) with the backing plate 11 is disposed on the back surface of the backing plate 11. . For this reason, as shown by the arrows in FIG. 2, the cooling water cooled by appropriate cooling means (not shown) along the water jacket 14a is transferred from the inlet of the cooling water to the outlet of the backing plate 11. It flows in a substantially U shape while touching. According to such a substantially U-shaped water jacket 14a, the range in which the cooling water pressure is applied to the backing plate 11 can be set to a necessary and minimum, and deformation due to the water pressure of the backing plate 11 can be suppressed. .

  In this verification experiment, for the purpose of monitoring the temperature of the cooling water flowing through the backing plate 11, as shown in FIG. 2, the cooling water inlet side thermometer T1 for detecting the cooling water inlet temperature and the cooling water outlet temperature are detected. And a cooling water outlet side thermometer T2 for detecting the above.

  Next, the result of verifying whether or not there is a change in the cooling capacity of the target by the backing plate when the sputtering apparatus is operating and when venting will be described with reference to FIG.

  In FIG. 3, the horizontal axis represents the time elapsed since the start of sputtering discharge, the left vertical axis represents the cooling water temperature, the right vertical axis represents the vacuum tank pressure, and the cooling water inlet temperature, cooling water outlet temperature, and vacuum It is the figure which showed an example of the time-dependent change of a tank pressure.

  As a result of this verification experiment, the cooling water inlet temperature gradually changes over the entire period, regardless of whether the sputtering apparatus 100 is in operation (sputtering period) or venting (venting end), as shown by a one-dot chain line in FIG. However, as shown by the solid line in FIG. 3, the cooling water outlet temperature was found to have an unexpected and rapid temperature rise in the R region after the end of venting. Note that the temperature rise of the cooling water outlet temperature during the sputtering period is due to the high temperature of the target 10 by sputtering, and the gradual decrease in the cooling water outlet temperature from the end of sputtering to the start of venting is the target 10 by the end of sputtering. This is thought to be due to the left-over cooling.

  Here, the inventor of the present invention estimates the cause of the temperature rise of the cooling water outlet temperature in the R region as follows.

  4 is a cross-sectional view showing the periphery of the center in the width direction of the target and the backing plate of the target assembly unit shown in FIG. 1, and is a diagram for explaining the temperature rise of the coolant outlet temperature in the R region shown in FIG. It is. FIG. 4A illustrates a predicted form of the target and the backing plate when the sputtering apparatus is vented, and FIG. 4B illustrates a predicted form of the target and the backing plate when the sputtering apparatus is operated. Yes.

  When the sputtering apparatus 100 is vented, the internal space S (FIG. 1) of the vacuum chamber 40 is in an atmospheric pressure P1 state. In this state, no differential pressure is generated between the front surface 11a of the backing plate 11 (contact surface with the target 10) and the back surface 11b of the backing plate 11 (surface on the magnet unit M side). As shown in FIG. 4A, the back surface of the flat target 10 and the surface 11a of the flat backing plate 11 are in close contact with each other over substantially the entire area.

  On the other hand, when the sputtering apparatus 100 is in operation, the internal space S of the vacuum chamber 40 is in a state of negative pressure P2. In this state, a differential pressure ΔP (P1−P2) based on the atmospheric pressure P1 and the negative pressure P2 is generated between the front surface 11a of the backing plate 11 and the back surface 11b of the backing plate 11. Incidentally, the peripheral edge of the backing plate 11 is screwed to the casing 13 with bolts 15 as shown in FIG. For this reason, the screw stop part (peripheral part of the backing plate 11) by the said bolt 15 becomes a 4 side support fixing part at the time of the deformation | transformation by the differential pressure (DELTA) P of the backing plate 11 assumed. Therefore, as shown in FIG. 4B, a distributed load due to the differential pressure ΔP between the atmospheric pressure P1 and the negative pressure P2 is applied to the back surface 11b of the backing plate 11, and the backing plate is caused by the distributed load. 11 is bent, and a gap G between the back surface of the target 10 and the front surface 11a of the backing plate 11 is generated. For example, assuming a four-sided simple support of the backing plate, when a distributed load corresponding to atmospheric pressure is applied to a copper backing plate having a width of 250 mm × length of 1300 mm × thickness of 15 mm, the amount of deflection at the center of the backing plate The (maximum deflection amount) is predicted to be about 0.14 mm from the known maximum deflection formula.

  According to the above-described consideration, the temperature increase of the cooling water outlet temperature in the R region shown in FIG. 3 is caused by the gap G between the back surface of the target 10 and the surface 11a of the backing plate 11 caused by the bending deformation of the backing plate 11. This phenomenon is thought to support the formation of That is, when the sputtering apparatus 100 is in operation, as shown in FIG. 4B, the presence of the gap G between the back surface of the target 10 and the front surface 11 a of the backing plate 11 reduces the contact area between the two, and the high temperature target 10. In spite of the deterioration of the heat transfer characteristics of the backing plate 11, the adhesion between the back surface of the target 10 and the surface 11 a of the backing plate 11 is enhanced by the vent of the sputtering apparatus 100. As a result, it is presumed that the heat of the target 10 is easily transferred to the cooling water via the backing plate 11 and the cooling water outlet temperature is increased.

  The existence of such a gap G acts so as to inhibit heat exchange between the target 10 in a high temperature state during operation of the sputtering apparatus 100 and the cooling water flowing through the backing plate 11, and the target 10 by the backing plate 11. Reduce the cooling capacity. Therefore, it is necessary from the viewpoint of achieving high cooling efficiency of the sputtering apparatus 100 to design the backing plate 11 so as to eliminate the gap G as much as possible.

  Hereinafter, the configuration of the target assembly unit and the sputtering apparatus according to the embodiment of the present invention based on the design guideline of the backing plate 11 will be described.

  However, the configuration of the sputtering apparatus of the present embodiment is the same as the configuration of the sputtering apparatus 100 shown in FIG. 1 except for the forms of the target 10 and the backing plate 11 of the target assembly unit T. For this reason, description and illustration of the configuration common to both are omitted. For convenience, the components other than the target and the backing plate will be described using the same reference numerals as the reference symbols of the respective components shown in FIG.

  FIG. 5 is a cross-sectional view showing the periphery of the center in the width direction of the target and the backing plate of the target assembly unit according to the embodiment of the present invention. FIG. 5A illustrates a predicted form of the target and the backing plate when the sputtering apparatus is vented, and FIG. 5B illustrates a predicted form of the target and the backing plate when the sputtering apparatus is in operation. Yes.

  As shown in FIG. 5A, the surface 111a of the backing plate 111 is cut into a curved shape (concave surface). Then, the target 110 in a flat state (initial state) is elastically deformed in a curved shape along the surface 111 a of the backing plate 111 based on a fixed deformation force (external force) between the backing plate 111 and the target 110 by the bolt 19. Is done. In this case, the curvature (curved shape) of the surface 111a of the backing plate 111 is such that, when the backing plate is fixedly supported by the bolt 15 (see FIG. 1), the back surface 111b of the backing plate 111 is operated when the sputtering apparatus 100 is in operation. The surface 111a of the backing plate 111 is set to be flat by the distributed load deflection of the backing plate 111 due to the differential pressure ΔP (P1-P2) (see FIG. 5B). In this way, when the sputtering apparatus 100 is in operation, the surface 111a of the backing plate 111 is flattened, and the elastically deformed target 110 is removed from the external force and returned to the flat initial state. Thereby, the target 110 can be leveled during sputtering of the target 110, and adhesion between the back surface of the target 110 and the surface 111 a of the backing plate 111 can be appropriately maintained when the sputtering apparatus 100 is in operation. However, in FIG. 5B, the surface 111a of the backing plate 111 is illustrated to be flattened by the distributed load deflection of the backing plate 111. However, the surface 111a does not necessarily have to return to a flat state, and has a concave shape. It may be in a curved state. In other words, the adhesion between the back surface of the target 110 and the surface 111a of the backing plate 111 can be appropriately maintained as long as the surface 111a of the backing plate 111 does not curve in a reverse direction beyond the flat state.

  Note that the specific curvature (curvature) of the surface 111a of the backing plate 111 may be easily derived from a known maximum deflection type, but if the backing plate is in a complicated form (for example, inside the backing plate) In the case of forming a hollow space through which cooling water flows, a numerical calculation may be performed by a structural analysis simulation technique. Further, by placing the backing plate 111 in the sputtering apparatus 100, the amount of deflection of the backing plate 111 may be confirmed at the actual machine level. During operation, the surface 111a of the flat backing plate 111 may be shaved.

As described above, according to the target assembly unit T and the sputtering apparatus 100 of the present embodiment, the adhesion between the back surface of the target 110 and the front surface 111a of the backing plate 111 is improved when the sputtering apparatus 100 is in operation. Thus, the cooling capacity (cooling efficiency) of the target 110 by the backing plate 111 during the operation is appropriately ensured.
(Modification 1)
FIG. 6 is a cross-sectional view showing the periphery of the center in the width direction of the target and the backing plate of the target assembly unit according to the first modification of the present invention. FIG. 6A illustrates a predicted form of the target and the backing plate when the sputtering apparatus is vented, and FIG. 6B illustrates a predicted form of the target and the backing plate when the sputtering apparatus is operated. Yes.

  In the above embodiment, the example in which the surface 111a of the backing plate 111 is cut into a curved concave surface has been described. However, the copper backing plate 211 of the present modified example is configured to bend by plastic deformation, for example, in an initial state. Has been.

  As shown in FIG. 6A, the flat target (initial state) aluminum target 210 is based on the fixed deformation force (external force) between the backing plate 211 and the target 210 by the bolt 19. It is elastically deformed into a curved shape along the surface 211a. In this case, the curvature (curved shape) of the backing plate 211 is different from the back surface 211b of the backing plate 211 when the sputtering apparatus 100 is in operation when the backing plate is fixedly supported by the bolt 15 (see FIG. 1). The surface 211a of the backing plate 211 is set flat by the distributed load deflection of the backing plate 211 due to the pressure ΔP (P1-P2) (see FIG. 6B). In this way, when the sputtering apparatus 100 is in operation, the surface 211a of the backing plate 211 is flattened, and the elastically deformed target 210 is removed from the external force and returned to a flat initial state. Thereby, the target 210 can be leveled during sputtering of the target 210, and the adhesion between the back surface of the target 210 and the surface 211a of the backing plate 211 can be appropriately maintained when the sputtering apparatus 100 is operated. Effects equivalent to those described in the embodiment can be obtained. However, in FIG. 6B, the surface 211a of the backing plate 211 is returned to the flat state by the distributed load deflection of the backing plate 211. However, the surface 211a does not necessarily need to be returned to the flat state, and has a concave shape. It may be in a curved state. That is, if the surface 211a of the backing plate 211 does not curve in a reverse direction beyond the flat state, the adhesion between the back surface of the target 210 and the surface 211a of the backing plate 211 can be appropriately maintained.

In FIG. 6, the target 210 and the backing plate 211 are shown to have the same thickness, but if the thickness of the target 210 is made thinner than the thickness of the backing plate 211 exposed to atmospheric pressure, the target 210 is It is suitable for elastic deformation. However, since the Young's modulus of the aluminum target 210 of this modification is smaller than the Young's modulus of the copper backing plate 211 of this modification, the target 210 can be appropriately elastically deformed even if both have the same thickness. .
(Modification 2)
FIG. 7 is a cross-sectional view showing the periphery of the center in the width direction of the target and the backing plate of the target assembly unit according to the second modification of the present invention.

  As shown in FIG. 7, the copper backing plate 311 of this modification is configured to be flat, while the aluminum target 310 of this modification is configured to be curved by plastic deformation, for example. For this reason, the target 310 in a curved state (initial state) is elastically deformed flatly along the surface 311a of the backing plate 311 based on a fixed deformation force (external force) between the backing plate 311 and the target 310 by the bolt 19. Is done. In this case, the curvature of curvature of the target 310 (curved shape) is the differential pressure to the back surface 311b of the backing plate 311 when the sputtering apparatus 100 is in operation when the backing plate is fixedly supported by the bolt 15 (see FIG. 1). Is set to be the same as the curvature of curvature of the surface 311a of the backing plate 311 due to the distributed load deflection of the backing plate 311. In this way, during the operation of the sputtering apparatus 100, the elastically deformed target 310 can return to the initial state after the external force is removed. Thereby, when the sputtering apparatus 100 is in operation, the adhesion between the back surface of the target 310 and the front surface 311a of the backing plate 311 is appropriately maintained, and as a result, an effect equivalent to the effect described in the above embodiment can be obtained. . However, here, the curvature of the surface 311a of the backing plate 311 due to the distributed load deflection of the backing plate 311 is exemplified to be the same as the curvature of the curvature of the target 310 in the initial state. The curvature is not necessarily the same as the curvature of the curvature of the target 310. That is, if the curvature of the surface 311a of the backing plate 311 is larger than the curvature of the curvature of the target 310, the adhesion between the back surface of the target 310 and the surface 311a of the backing plate 311 can be appropriately maintained.

In FIG. 7, the target 310 and the backing plate 311 are shown to have the same thickness, but if the thickness of the target 310 is made thinner than the thickness of the backing plate 311 exposed to atmospheric pressure, the target 310 is It is suitable for elastic deformation. However, since the Young's modulus of the aluminum target 310 of this modification is smaller than the Young's modulus of the copper backing plate 311 of this modification, the target 310 can be appropriately elastically deformed even if both have the same thickness. .
(Modification 3)
In the embodiment and the first and second modified examples 1 and 2, as the load applied to the back surface of the backing plate, a distributed load due to the differential pressure between the atmospheric pressure on the back surface side of the backing plate and the negative pressure on the front surface side of the backing plate is illustrated. However, the load applied to the back surface of the backing plate is not limited to this.

For example, when a cooling structure in which the entire magnet unit M is immersed in a cooling water container (not shown) in which cooling water is stored and a backing plate is also used as a lid of the cooling water container is used, The water pressure of the water is superimposed on the back surface of the backing plate as a distributed load.
(Modification 4)
As a connecting method between the target and the backing plate, screwing with a bolt has been exemplified so far in consideration of easy attachment / detachment between the two. However, the connection method between the two is not limited to this, and other point connection methods (riveting or spot welding) may be used instead of screw fixing.

  According to the target assembly unit of the present invention, while the sputtering apparatus is in operation (depressurization) while improving the efficiency of target replacement, preventing in-plane thermal distortion of the target, reusing the backing plate, and facilitating wide erosion of the target. The cooling capacity of the target by the cooling plate can be appropriately secured. Therefore, the present invention can be used as a target assembly unit for a sputtering apparatus used in a manufacturing process of, for example, a semiconductor element or an LCD.

It is sectional drawing of the target assembly unit periphery of the sputtering device used for the measurement of the cooling capacity of the target by the backing plate at the time of operation of a sputtering device and a vent. It is the figure which planarly viewed the back surface side of the target assembly unit shown in FIG. The horizontal axis represents the time elapsed since the start of sputtering discharge, the left vertical axis represents the cooling water temperature, the right vertical axis represents the vacuum chamber pressure, and the cooling water inlet temperature, cooling water outlet temperature, and vacuum chamber pressure elapsed time It is the figure which showed an example of the change. It is sectional drawing which showed the width direction center part periphery of the target of a target assembly unit shown in FIG. 1, and a backing plate, (a) is drawing the prediction form of the target at the time of venting of a sputtering device, and a backing plate, In (b), a predicted form of the target and the backing plate during operation of the sputtering apparatus is depicted. It is sectional drawing which showed the width direction center part periphery of the target and backing plate of the target assembly unit by embodiment of this invention, (a) is drawing the prediction form of the target at the time of venting of a sputtering device, and a backing plate. , (B) shows the predicted form of the target and the backing plate when the sputtering apparatus is in operation. It is sectional drawing which showed the width direction center part periphery of the target and backing plate of the target assembly unit by the modification 1 of this invention, (a) draws the prediction form of the target at the time of venting of a sputtering device, and a backing plate (B) shows a predicted form of the target and the backing plate when the sputtering apparatus is in operation. It is sectional drawing which showed the width direction center part periphery of the target and backing plate of the target assembly unit by the modification 2 of this invention.

Explanation of symbols

10, 110, 210, 310 Target 11, 111, 211, 311 Backing plate 11a, 111a, 211a, 311a Front surface 11b, 111b, 211b, 311b Back surface 12 Metal shield plate 13 Casing 13a Backing plate contact surface 13b Tube portion 13c １４ part 14 Cooling water guide plate 14a Water jacket 15 Second connecting means (bolt)
19 1st connection means (bolt)
16, 17, 18 O-ring 20 Central magnet 21 External magnet 22 Yoke 23 Insulating flange 40 Vacuum chamber 40a Wall hole 100 Sputtering device B Leakage magnetic field C Erosion E Electric field T Target assembly unit T1 Cooling water inlet side thermometer T2 Cooling water outlet side Thermometer L Center line M Magnet unit P1 Atmospheric pressure P2 Negative pressure ΔP Differential pressure S Internal space V Vacuum pump

Claims (9)

A sputtering target;
Fixing the target via the first connecting means, and a cooling plate supported by the casing via the second connecting means,
The target assembly unit, wherein the target is elastically deformed along the surface of the cooling plate based on an external force of the first connecting means. The surface of the cooling plate is formed in a curved shape,
The target assembly unit according to claim 1, wherein the target in a flat state is elastically deformed into a curved shape. The surface of the cooling plate is formed flat,
The target assembly unit according to claim 1, wherein the curved target is elastically deformed flat.   The said 1st connection means is located in the approximate center part of the width direction of the said cooling plate and the said target, and the said 2nd connection means is located in the peripheral part of the said cooling plate. The target assembly unit described.   The shape of the surface of the cooling plate is flat when the cooling plate is bent and supported by the load applied to the back surface of the cooling plate when the cooling plate is fixedly supported on the casing by the second connecting means. The target assembly unit according to claim 2, wherein the target assembly unit is set as follows.   The target assembly unit according to claim 5, wherein the cooling plate is curved.   The target assembly unit according to claim 5, wherein a surface of the cooling plate is cut into the curved shape.   The target assembly unit according to claim 5, wherein, when the surface of the cooling plate is exposed to a reduced internal space, the load is a distributed load due to a differential pressure between the pressure of the internal space and atmospheric pressure. A vacuum chamber having an internal space decompressed by a vacuum exhaust means;
It is attached to the wall part of the vacuum chamber via an insulating member, and is disposed so as to airtightly expose the surface of the target and the cooling plate to the internal space. A target assembly unit;
Magnetic field generating means disposed on the back side of the cooling plate;
A sputtering apparatus comprising:

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