Method for detecting joining state of target and film forming device

Abstract

Provided are a method for detecting a joining state of a target, the method making it possible to detect peeling even when a small amount of peeling occurs in the target, and a film forming device. The film forming device 1 determines the joining state of a target 231 on the basis of a pattern of a temperature change in the target 231 at prescribed times T1 and T2. Temperature sensors 237b, 238b detect the temperature of the target 231 and / or a target base 232 at the prescribed time T1 from the start of the film formation or the prescribed time T2 after the end of the film formation. A calculation unit 45 calculates a temperature change over time at a prescribed time on the basis of the detected temperature of the target and / or the target base. A joining state determination unit 46 determines the joining state of the target 231 on the basis of the temperature changes over time at the prescribed times T1 and T2.

Description

Target bonding state detection method and film formation device

[0001] The present invention relates to a method for detecting a bonding state of a target and a film forming apparatus.

[0002] In the manufacturing processes of various products such as semiconductors, displays, and optical disks, thin films such as optical films are sometimes formed on workpieces such as wafers and glass substrates. Thin films can be created by repeatedly forming a metal film or other material on the workpiece and then subjecting the formed film to film treatments such as etching, oxidation, or nitriding.

[0003] Such film formation and film processing can be performed by various methods, one of which is using plasma. In film formation, an inert gas is introduced into a chamber, which is a vacuum container in which a target is placed, and a DC voltage is applied. Ions of the inert gas that has been converted into plasma are caused to collide with the target, and the material that is knocked out from the target is deposited on the workpiece to form a film. In film processing, a process gas is introduced into a chamber in which an electrode is placed, and a high-frequency voltage is applied to the electrode. Film processing is performed by causing the ions of the process gas that has been converted into plasma to collide with a film on the workpiece.

[0004] A sputter-down type film formation apparatus is known in which, during film formation, a target bonded to the lower surface of a target base via a bonding material is placed on the upper surface inside a vacuum chamber, an electric field is formed on the lower surface of the target to generate plasma, and the target is sputtered by ions from the plasma. The target is cooled via the target base by a cooling mechanism.

[0005] Japanese Patent Application Laid-Open No. 2017-166032

[0006] In a film deposition apparatus, the target may peel off and fall off from the target base due to excessive power input to the target, insufficient cooling of the target base by the cooling mechanism, or poor compatibility between the target material and the bonding material, etc. In particular, in the case of a sputter-down type film deposition apparatus, a fallen target can cause long-term shutdowns or equipment failure.

[0007] A possible method for detecting target detachment is to use a cooling mechanism for cooling the target. In the case of a water-cooled cooling mechanism using a coolant, a possible method is to detect the temperature Te_out of the outlet side of the cooling water for cooling the target, and if the temperature exceeds a threshold, it is determined that the target has detached.

[0008] However, when the target peels off slowly, the cooling water discharge side temperature Te_out does not change beyond the threshold value, and small peeling of the target cannot be detected.

[0009] The embodiments of the present invention have been proposed to solve the above-mentioned problems, and their purpose is to provide a method for detecting the bonding state of a target, and a film forming apparatus, which are capable of detecting even small peeling of the target.

[0010] A film formation apparatus according to an embodiment of the present invention is a film formation apparatus that forms a film on a workpiece using plasma, and includes: an airtight container into which the workpiece is carried; a target placed in the airtight container; a target base that holds the target on one side; a temperature detection unit that detects the temperature of the target and / or the target base at a predetermined time after the end of the film formation process or at a predetermined time from the start of the film formation process after a specific time has elapsed since the end of the film formation process; a calculation unit that calculates the change in temperature over time over the predetermined time based on the detected temperature of the target and / or the target base; and a bonding state determination unit that determines the bonding state of the target based on the change in temperature over time over the predetermined time.

[0011] Furthermore, a bonding state detection method according to an embodiment of the present invention is a method for detecting the bonding state of a target in a film formation apparatus that forms a film on a workpiece using plasma, and includes a temperature detection step of detecting the temperature of the target and / or target base at a predetermined time after the end of the film formation process or at a predetermined time from the start of the film formation process after a specific time has elapsed since the end of the film formation process; a calculation step of calculating a change in temperature over time over the predetermined time based on the detected temperature of the target and / or the target base; and a bonding state determination step of determining the bonding state of the target based on the change in temperature over time.

[0012] According to the film forming apparatus of the embodiment of the present invention, even when a small peeling of the target occurs, the peeling can be detected.

[0013] 8A is a schematic diagram showing a film forming apparatus according to a first embodiment; FIG. 8B is a perspective view showing a cooling plate according to the first embodiment; FIG. 8C is a bottom view showing a cooling plate according to the first embodiment; FIG. 8D is a block diagram showing the configuration of a control device according to the first embodiment; FIG. 8E is a graph showing the in / out temperature difference of the cooling water of a non-defective target stored in a reference temperature storage unit according to the first embodiment; FIG. 8F is a graph showing the in / out temperature difference of the cooling water indicating that the target has reached a steady state after steady operation for a certain period of time; FIG. 8G is a graph showing a change pattern of the in / out temperature difference of the cooling water between a non-defective target and a damaged target; and FIG. 8H is a flowchart showing a target bonding state detection process according to the first embodiment; FIG. 8H is a graph showing the change pattern of the in / out temperature difference of the cooling water between a non-defective target and a damaged target; and FIG. 8H is a graph showing the ON / OFF of the applied voltage by the power supply device corresponding to the change pattern of the in / out temperature difference of the cooling water in FIG. 8A. FIG. 1 is a block diagram showing the configuration of a control device of a modified example of the first embodiment. FIG. 2 is a graph showing the ratio of exhaust heat to the elapsed time since heat input was stopped in a modified example of the first embodiment. FIG. 3 is a schematic diagram showing a film formation apparatus of a second embodiment. FIG. 4 is a block diagram showing the configuration of a control device of a second embodiment. FIG. 5 is a graph showing a simulation of the correlation between the temperature of the target and the temperature of the target base, which changes over time, after a film formation process using a Cr target in the film formation apparatus of the second embodiment. FIG. 6 is a flowchart showing a target bonding state detection process in the second embodiment. FIG. 7 is a graph showing the correlation between the target temperature and the target base temperature.

[0014] An embodiment of the present invention (hereinafter referred to as the present embodiment) will be specifically described with reference to the drawings. Note that the drawings are schematic diagrams, and the size, proportions, etc. of each part are exaggerated for ease of understanding.

[0015] [1. First Embodiment] [1-1. Configuration] A first embodiment of the present invention will be described with reference to the drawings.

[0016] The film forming apparatus 1 is a film forming apparatus that uses plasma to form a film on a workpiece W. As shown in Fig. 1, the film forming apparatus 1 has a stage 21 on which the workpiece W is placed, installed near the bottom of a chamber 2 that is an airtight container. The type of the workpiece W is not limited to a specific one, but is, for example, a glass substrate.

[0017] The stage 21 is disk-shaped and is connected to and supported by a shaft 22 extending from the bottom surface of the chamber 2. The shaft 22 airtightly penetrates the bottom surface of the chamber 2 and communicates with the outside. The chamber 2 is provided with an exhaust device 25 and a pressure gauge 26. The exhaust device 25 is, for example, a pump, and constantly exhausts the inside of the chamber 2 to maintain a reduced pressure state. The pressure gauge 26 measures the pressure inside the chamber 2.

[0018] The chamber 2 is provided with a loading / unloading port 20 for the workpiece W. The loading / unloading port 20 is connected to a load lock chamber (not shown), and the workpiece W is loaded from outside the film forming apparatus 1 into the chamber 2 via the load lock chamber. The load lock chamber is also equipped with an exhaust device. When the workpiece W is loaded into the chamber 2, the workpiece W is loaded into the load lock chamber, and then the load lock chamber is depressurized to a preset pressure. After the pressure is reduced to the preset pressure, the loading / unloading port 20 of the chamber 2 is opened, and the workpiece W is loaded into the chamber 2. By opening the loading / unloading port 20 after the pressure is reduced to the preset pressure, the increase in pressure in the chamber 2 can be reduced.

[0019] A sputtering source 23 is disposed at the top of the chamber 2. The sputtering source 23 is a supply source of a film-forming material that is deposited on the workpiece W to form a film. The sputtering source 23 is composed of a target 231, a target base 232, a bonding section 233, a cooling plate 235, an anode section 236, a water supply section 237, a water drain section 238, and a magnet section 239. A power supply unit 24 is connected to the sputtering source 23.

[0020] The target 231 is provided below the sputtering source 23 and is disposed so that its surface faces the stage 21 installed near the bottom of the chamber 2. In other words, the target 231 is installed inside the chamber 2. The target 231 is made of a film-forming material, and any well-known film-forming material can be used. In this embodiment, chromium (Cr) is used as the target 231. The shape of the target 231 is, for example, cylindrical. However, other shapes such as an oval cylindrical shape or a rectangular prism shape may also be used.

[0021] The upper surface of the target 231 is held on one surface of the target base 232 via a bonding portion 233. The target base 232 and the target 231 form a cathode. The target base 232 is, for example, a copper plate. The surface of the target base 232 opposite the stage 21 is held by a cooling plate 235. The bonding portion 233 is an adhesive layer made of a bonding material such as In or an In alloy, which bonds the target 231 and the target base 232 together.

[0022] When sputtering begins, ions in the plasma collide with the target 231. The impact of these ions causes particles of the film-forming material to fly out of the target 231, which are then deposited on the workpiece W, which is the substrate on which the film is to be formed, thereby forming a thin film. When a DC voltage is applied to the target 231 during film formation, the sputtering gas is converted into plasma, which becomes a heat source 234. During sputtering operation, the surface of the target 231 becomes hot due to the influence of the heat source 234. The target 231 is cooled by a cooling plate 235, which prevents melting of the bonding portion 233, stress caused by the difference in thermal expansion between the target 231 material and the bonding portion 233, and resulting peeling of the target 231 from the target base 232.

[0023] The cooling plate 235 serves to cool the target 231. The cooling plate 235 indirectly cools the object to be cooled, for example, using a coolant as a medium. In this embodiment, cooling water e flows through the cooling plate 235 as the coolant, and uniformly cools the target 231 via the target base 232. The cooling plate 235 has, for example, a cylindrical shape with one end closed. A surface that holds the other surface of the target base 232 is provided on the end surface of the one end. A flange 235c, a water supply port 235d, and a water discharge port 235e are provided on the other end of the cooling plate 235.

[0024] The flange 235c is formed at the other end of the cooling plate 235 so as to extend outward. The flange 235c is airtightly connected to a thick portion 236a1 of the TS distance adjustment portion 236a (described later) via an insulating member (not shown). The water supply port 235d is connected to the water supply portion 237 and is a water supply port for introducing cooling water e into the cooling plate 235. The outlet port 235e is connected to the drain portion 238 and is a outlet for discharging the cooling water e supplied into the cooling plate 235.

[0025] The surface (surface) of the cooling plate 235 that holds the target base 232 is larger than the surface of the target 231. As shown in FIGS. 2A and 2B , a concave groove 235b is formed in the surface of the cooling plate 235. The groove 235b is formed in an area on the surface of the cooling plate 235 that is at least equal to the area of ​​the surface of the target 231, but smaller than the area of ​​the surface of the cooling plate 235. The groove 235b has an inlet 235b1 and an outlet 235b2. The inlet 235b1 is connected to the water supply port 235d, and the outlet 235b2 is connected to the water outlet 235e. The groove 235b runs completely around the aforementioned area on the surface of the cooling plate 235 and is connected from the inlet 235b1 to the outlet 235b2. When the groove 235b is formed in the surface of the cooling plate 235, a sealant 235a, such as an O-ring, is provided on the surface of the cooling plate 235 to surround the groove 235b. The cooling plate 235 is fixed to the target base 232 via a sealant 235a such as an O-ring. A flow path 235f for the cooling water e is formed by the groove 235b and the fixed target base 232. The formed flow path 235f is sealed by the sealant 235a, so the cooling water e flows through the flow path 235f without leaking from the connection portion. In this embodiment, the flow path 235f is formed by the groove 235b of the cooling plate 235 and the target base 232, but this case is also included in the provision of the flow path 235f in the cooling plate 235.

[0026] Furthermore, the flow path 235f may be provided inside the cooling plate 235. In this case, the cooling water e will not leak from the connection portion with the target base 232, so the target base 232 and the cooling plate 235 may be connected without using the sealing material 235a.

[0027] The anode section 236 suppresses the generation of plasma other than on the surface of the target 231, and functions as an anode for the target 231 and the target base 232. The anode section 236 is composed of a TS distance adjustment section 236a and an anode ring 236b.

[0028] The TS distance adjustment unit 236a is a member capable of adjusting the distance (TS distance) between the target 231 and the workpiece W. The TS distance adjustment unit 236a has, for example, a cylindrical shape. One end of the TS distance adjustment unit 236a is inserted into the chamber 2 through an opening in the top surface of the chamber 2. One end of the TS distance adjustment unit 236a has a thick portion 236a1 whose inner periphery is thickened along the entire periphery. A flange 235c of the cooling plate 235 is airtightly connected to the thick portion 236a1 via an insulating member (not shown). With this structure, the target 231, the target base 232, the cooling plate 235, and the magnet unit 239 are arranged inside the anode unit 236. The other end of the TS distance adjustment unit 236a is provided outside the chamber 2. The other end of the TS distance adjustment part 236a has a flange 236a2 that protrudes in an annular shape so that the diameter expands outward. The TS distance adjustment part 236a is airtightly connected to the chamber 2 via the flange 236a2.

[0029] The TS distance adjustment unit 236a can change the TS distance by changing the length between the thick portion 236a1 and the flange 236a2. For example, a plurality of TS distance adjustment units 236a with different lengths between the thick portion 236a1 and the flange 236a2 are prepared in advance. By selectively using the TS distance adjustment units 236a with different lengths between the thick portion 236a1 and the flange 236a2, the TS distance can be changed to any desired value. Alternatively, the TS distance may be changed by providing a spacer (not shown) between the flange 236a2 of the TS distance adjustment unit 236a and the chamber 2. For example, the TS distance can be changed by changing the thickness of the spacer (not shown). The TS distance adjustment unit 236a is connected to ground.

[0030] The anode ring 236b suppresses the generation of plasma other than on the surface of the target 231 and functions as an anode for the target 231 and the target base 232. The anode ring 236b has, for example, a ring shape. The anode ring 236b is connected to one end of the TS distance adjustment unit 236a and is provided so as to surround the periphery of the target 231. This prevents argon molecules from colliding with the target base 232 and the like.

[0031] The water supply unit 237 supplies the cooling water e to a flow path 235f for the cooling water e formed in the cooling plate 235. The drainage unit 238 drains the cooling water e that has flowed through the flow path 235f for the cooling water e. That is, the water supply unit 237 and the drainage unit 238 are connected to the flow path 235f of the cooling plate 235. Temperature sensors 237b and 238b are provided in the water supply unit 237 and the drainage unit 238, respectively. The temperature sensors 237b and 238b correspond to temperature detection units and are connected to the control device 4. The detected temperatures (temperature Te of the cooling water e) detected by the temperature sensors 237b and 238b are transmitted to the control device 4 as a supply-side temperature Te_in of the cooling water e and a discharge-side temperature Te_out of the cooling water e. The supply-side temperature Te_in of the coolant e may be referred to as the temperature Te_in or temperature Te_in of the coolant e, and the discharge-side temperature Te_out of the coolant e may be referred to as the temperature Te_out or temperature Te_out of the coolant e.

[0032] The magnet unit 239 has the function of enclosing electrons in a magnetic field and creating a space with high electron density near the surface of the target 231. The magnet unit 239 is composed of a magnet 239a and a motor 239b. The magnet 239a generates a magnetic field near the surface of the target 231. The magnet 239a is rotated eccentrically by the motor 239b about the rotation axis of the motor 239b. The magnet 239a is a permanent magnet that is disposed behind the target 231 via the cooling plate 235 and generates a rotating magnetic field. The motor 239b is a driving source that rotates the magnet 239a. The motor 239b is connected to a power supply device (not shown), and by eccentrically rotating the magnet 239a, the magnetic field near the surface of the target 231 is varied. By varying the magnetic field near the surface of the target 231, the plasma density near the surface of the target 231 can also be varied. As a result, the area eroded by sputtering on the surface of the target 231 can be moved, thereby preventing one spot on the target 231 from being excessively eroded or heated.

[0033] The power supply device 24 is a component that applies a voltage to the target 231 via the target base 232. In other words, by applying a voltage to the target 231, the power supply device 24 converts the sputtering gas introduced around the target 231 into plasma, and deposits the film formation material on the workpiece W. In this embodiment, the power supply device 24 is, for example, a DC power supply that applies a high voltage. In this embodiment, the power supply device 24 is connected to a cooling plate 235. As a result, the power supply device 24 is connected to the target base 232 via the cooling plate 235. Note that in the case of an apparatus that performs high-frequency sputtering, the power supply device 24 can also be an RF power supply.

[0034] The chamber 2 is also provided with a sputtering gas inlet 27. A sputtering gas is introduced into the chamber 2 from the sputtering gas inlet 27. The sputtering gas is not limited to a specific one, but in this embodiment, an inert gas such as argon can be used. The sputtering gas inlet 27 is composed of an argon gas inlet 271a and a flow controller 271b. The argon gas inlet 271a is an argon gas supply source such as a cylinder. The flow controller 271b measures and controls the flow rate of the argon gas, thereby introducing the argon gas into the chamber 2 at a predetermined flow rate.

[0035] [Control Device] The control device 4 controls the operation of each part of the film forming apparatus 1. This control device 4 can be configured, for example, by a dedicated electronic circuit or a computer that operates according to a predetermined program. The control contents of each part are programmed in the control device 4, and are executed by a processing device such as a PLC or CPU. This makes it possible to accommodate a wide variety of film forming specifications.

[0036] The control device 4 also has a function of determining the bonding state of the target 231 based on the change in temperature of the target 231 and / or the target base 232 over time during a predetermined time T2 after the end of the film formation process or a predetermined time T1 from the start of the film formation process after a specific time Tsp has elapsed since the end of the film formation process, i.e., the change pattern in temperature of the target 231 and / or the target base 232. The configuration of the control device 4 will be described with reference to the virtual functional block diagram of Figure 3. The control device 4 includes a film formation processing unit 41, a reference temperature storage unit 43, a memory unit 44, a calculation unit 45, a bonding state determination unit 46, a notification unit 47, and an input / output control unit 48.

[0037] The film formation processing unit 41 is a processing unit that performs film formation processing by controlling the mechanisms of each unit of the film formation apparatus 1. Examples of the control contents include control of opening and closing of the load lock chamber and control of the pressure inside the load lock chamber, control of the pressure inside the chamber 2, opening and closing of the load / unload port 20, control of the exhaust speed of the exhaust device 25, control of the introduction timing and introduction amount of the sputtering gas inlet 27, control of the voltage application timing and supply amount of power in the power supply device 24, and control of the timing to detect changes in temperature over time in the target 231 and / or the target base 232.

[0038] The film forming processing unit 41 acquires the pressure inside the chamber 2 from the pressure gauge 26 and checks whether the pressure inside the chamber 2 has reached the base pressure. The base pressure is the pressure inside the chamber 2 at which sputtering gas may be introduced. Specifically, after the workpiece W is loaded into the chamber 2 and the loading / unloading port 20 is closed, the pressure inside the chamber 2 is reduced to the base pressure by exhausting the gas for a predetermined time using the exhaust device 25. After the base pressure is reached, the sputtering gas introduction unit 27 controls the argon gas flow rate controller 271b to introduce argon gas into the chamber 2 at a predetermined flow rate. As a result, the pressure inside the chamber 2 becomes an arbitrary pressure.

[0039] The reference temperature storage unit 43 is a storage means such as a memory. The reference temperature storage unit 43 stores the temperature change of the non-defective target during a predetermined time T1 from the start of the film formation process after a specific time Tsp has elapsed since the end of the film formation process, or during a predetermined time T2 from the end of the film formation process, in association with the elapsed time t. Here, a non-defective target refers to a target in a state where no melting or peeling due to stress has occurred at the bonding portion 233 and no peeling of the target 231 has occurred.

[0040] Peeling of the target 231 refers to either or both of peeling of the target 231 from the bonding portion 233 and peeling of the target base 232 from the bonding portion 233. In this case, "peeling of the target 231" includes very small peeling in the initial stage of peeling (very small peeling in the initial stage) to large peeling that leads to the falling off of the target 231. Note that the small peeling that occurs before the target 231 falls off, which will be described later, is peeling that is larger than the very small peeling in the initial stage and smaller than the large peeling that leads to the falling off of the target 231.

[0041] The index value for determining small delamination before the target 231 falls off is preferably set to a value with a certain margin relative to the index value for determining large delamination that leads to the target 231 falling off. In other words, it is preferable to determine delamination if the index value for small delamination is reached before reaching the index value for large delamination. For example, the absolute value of the "temperature curve slope" at the time of large delamination is determined in advance by experiment, and a value that has a margin from that value and is larger when compared in absolute value is set as the index value for small delamination. In this way, if delamination is detected when the index value for small delamination is reached, it is possible to prevent the target 231 from falling off. Alternatively, the difference between the index value for small delamination and the absolute value of the slope of the temperature curve of a non-defective target may be calculated, and if the difference in slope is within this value, it may be determined that no delamination has occurred.

[0042] The predetermined time T1 is a predetermined time from the start of the film formation process after a specific time Tsp has elapsed since the end of the film formation process, and the predetermined time T2 is a predetermined time from the end of the film formation process. The predetermined time T1 and the predetermined time T2 can be determined appropriately depending on the film formation conditions and the target material. In this embodiment, "predetermined" means that the time is set in advance in the storage means of the control device 4, and "predetermined time" can be read as a "set time" that is set in advance. The specific time Tsp is the time it takes for the heated target 231 to cool down to room temperature. The specific time Tsp is, for example, 180 seconds (s) or more, and in this embodiment, the specific time Tsp is 180 s. The specific time Tsp is also set in advance in the storage means of the control device 4.

[0043] The temperature change of the non-defective target can be measured by directly measuring the temperature of the target 231 or by indirectly measuring the temperature of the target 231. A method for indirectly measuring the temperature change of the non-defective target can be to use the temperature Te of the cooling water e before and after cooling the target 231, i.e., the temperature Te_in and the temperature Te_out. For example, a method can be used for calculating the temperature difference between the temperatures Te_in and Te_out (the in / out temperature difference of the cooling water e). That is, the temperature sensors 237b and 238b detect the temperature of the target 231 and / or the target base 232 at a predetermined time T2 after the end of the film formation process or at a predetermined time T1 from the start of the film formation process after a specific time Tsp has elapsed since the end of the film formation process. In the following description, the in / out temperature difference of the cooling water e may also be referred to as the cooling water in / out temperature difference or the in / out temperature difference. 4 is a graph showing the in / out temperature difference of the cooling water e for a non-defective target stored in the reference temperature storage unit 43. Fig. 4 shows the in / out temperature difference of the cooling water e from immediately after the start of the film formation process for a non-defective target until 180 seconds have elapsed since the end of the film formation process. In the graph, the period from the start of the film formation process until 80 seconds have elapsed (0 s to 80 s) is defined as the predetermined time T1, and the period from the end of the film formation process until 180 seconds have elapsed (710 s to 890 s) is defined as the predetermined time T2.

[0044] 4 shows a case where film formation with a short film formation time is performed on a plurality of workpieces W. In this case, the time required for one film formation is 65 seconds. The case where the film formation time is short refers to a case where the target 231 is not in a steady state.

[0045] Furthermore, as shown in FIG. 4, when film formation is performed multiple times, the entire process of film formation performed multiple times is referred to as a "film formation process." In this case, the start of one of the film formations that is repeated multiple times is referred to as a "film formation start," and the end of the film formation is referred to as a "film formation end." Furthermore, among the film formations that are repeated multiple times, the start of the first film formation is referred to as a "film formation process start," and the end of the last film formation is referred to as a "film formation process end." Furthermore, the film formation process refers to a state in which film formation is separated from one film formation by a specific time Tsp. Therefore, only one film formation may be performed in one film formation process, and the "film formation process start" may also be referred to as "the film formation process start after a specific time Tsp has elapsed since the film formation process end."

[0046] The memory unit 44 is a memory unit that stores the temperature of the target 231 to be determined. When the temperature of the target 231 is measured indirectly, the memory unit 44 stores the temperatures Te_in and Te_out detected by the water supply unit 237 and the water drain unit 238. When the film formation process is started, the temperatures Te_in and Te_out are transmitted to the control device 4 from the temperature sensors 237b and 238b. The memory unit 44 stores the temperatures Te_in and Te_out for a predetermined time (predetermined time T1 or T2) from the start of the film formation process or from the end of the film formation process. The memory unit 44 may also store the temperatures Te_in and Te_out detected by the water supply unit 237 and the water drain unit 238 from the start of the film formation process to the end of the film formation process. Alternatively, the storage unit 44 may store the temperatures Te_in and Te_out detected at the water supply unit 237 and the water discharge unit 238 while the film forming apparatus 1 is operating.

[0047] The calculation unit 45 calculates the in / out temperature difference of the cooling water e from the temperatures Te_in and Te_out stored in the storage unit 44 and arranges the calculated temperature differences by elapsed time t. That is, the calculation unit 45 calculates the change in temperature over time for a predetermined time T1 (T2) based on the temperatures Te_in and Te_out (the detected temperatures of the target 231 and / or the target base 232). The in / out temperature difference calculated by the calculation unit 45 may be only for the predetermined time T1 or the predetermined time T2. However, for the sake of explanation, the following description will be given assuming that the in / out temperature difference is calculated from immediately after the start of the film formation process until 300 seconds have elapsed since the end of the film formation process.

[0048] The bonding state determination unit 46 is a determination unit that compares the in / out temperature difference of the cooling water e of a non-defective target stored in the reference temperature storage unit 43 with the in / out temperature difference of the cooling water e of the target 231 attached to the film forming apparatus 1 to determine the bonding state of the target 231. In other words, the bonding state determination unit 46 is a determination unit that determines the bonding state of the target 231 based on a change in temperature over time over a predetermined time T1 (T2). For example, as shown in FIG. 6 , the bonding state determination unit 46 compares the slopes of the plots (temperature curves) of the in / out temperature difference of the cooling water e of a non-defective target and the target 231 attached to the film forming apparatus 1 at the predetermined time T1 or T2, and makes a determination. A specific determination method will be described later.

[0049] When a small peeling before the target 231 falls off is detected, the notification unit 47 notifies an output device 62 (described later). The input / output control unit 48 is an interface that controls signal conversion and input / output between each unit to be controlled.

[0050] Furthermore, an input device 61 and an output device 62 are connected to the control device 4. The input device 61 is an input means such as a switch, a touch panel, a keyboard, or a mouse that allows a user to operate the film forming apparatus 1 via the control device 4.

[0051] The output device 62 is an output means such as a display, lamp, meter, etc. that makes information for checking the status of the film forming apparatus 1 visible to the user, or a speaker, buzzer, etc. that makes information audible to the user.

[0052] [1-2. Action] Next, the operation of the film formation apparatus 1 and the film formation method according to this embodiment will be described with reference to Fig. 7. The operation of the film formation apparatus 1 described below is controlled by the film formation processing unit 41 of the control device 4. In the following, a Cr target having a diameter of 150 mm and a thickness of 10 mm is used.

[0053] The workpiece W is loaded into a load lock chamber (not shown) from outside at atmospheric pressure. After the load lock chamber is depressurized to a preset pressure, the loading / unloading port 20 is opened and the workpiece W is loaded into the chamber 2. The loaded workpiece W is placed on the stage 21. The workpiece W is loaded into the chamber 2 by a transport device (not shown). After the workpiece W is placed on the stage 21, the loading / unloading port 20 is closed and the chamber 2 is sealed. Because the chamber 2 is constantly evacuated by the exhaust device 25, the chamber 2 is depressurized by closing the loading / unloading port 20.

[0054] When a predetermined exhaust time has elapsed since the loading / unloading port 20 was closed, the control device 4 acquires the pressure value inside the chamber 2 from the pressure gauge 26. If the pressure inside the chamber 2 is equal to or lower than the base pressure, the film forming processing unit 41 introduces argon gas into the chamber 2.

[0055] Specifically, the film formation processing unit 41 controls the flow rate controller 271b of the sputtering gas introduction unit 27 to introduce argon gas at a predetermined flow rate into the chamber 2. As a result, the pressure inside the chamber 2 is set to a desired value.

[0056] After the above steps, film formation begins (S01: film formation process start step). Argon gas is introduced into the chamber 2 from the sputtering gas inlet 27, and when the interior of the chamber 2 reaches a desired pressure, a DC voltage is applied to the target 231 from the power supply 24. The application of the DC voltage converts the sputtering gas into plasma, generating ions. When the generated ions collide with the target 231, particles of the film formation material on the target 231 are ejected, and film formation begins. The ejected particles are deposited on the workpiece W placed on the stage 21, forming a thin film on the workpiece W.

[0057] When film formation is started, the memory unit 44 starts storing the temperatures Te_in and Te_out of the cooling water e (S02). That is, when film formation is started, the temperature Te of the cooling water e measured by the temperature sensors 237b and 238b (temperature detection step) is periodically transmitted to the control device 4. The memory unit 44 stores at least the temperatures Te_in and Te_out of the cooling water e for the predetermined time T1 and the predetermined time T2 transmitted from the temperature sensors 237b and 238b.

[0058] For example, if the control device 4 determines that the film formation that is about to be performed is the first film formation, it stores the temperatures Te_in and Te_out of the cooling water e from the time it is determined that the film formation process has started until the time when a predetermined time T1 has elapsed. Also, if the control device 4 determines that the film formation that is about to be performed is the last film formation, it stores the temperatures Te_in and Te_out of the cooling water e from the time it is determined that the film formation process has ended until the time when a predetermined time T2 has elapsed.

[0059] The control device 4 retrieves from the storage unit 44 the temperatures Te_in and Te_out of the cooling water e for a predetermined time T2 from the time when it is determined that the film formation process has ended or for a predetermined time T1 from the time when it is determined that the film formation process has started.

[0060] The calculation unit 45 calculates the coolant in / out temperature difference (S03: calculation step). The coolant in / out temperature difference is calculated from the difference between the temperature Te_out and the temperature Te_in retrieved from the memory unit 44. The difference is calculated from the temperature Te_out and the temperature Te_in when the elapsed time t is the same. The calculated coolant in / out temperature differences are sorted for each elapsed time t. This allows a pattern of change in the temperature difference over time for a predetermined time T1 (T2) to be obtained.

[0061] The target 231 receives heat from the heat source 234 (generated plasma). For example, ions generated from the plasma have energy. When this energy collides with the target 231, it is transferred to the target 231 as heat, causing the temperature of the target 231 to rise. To lower the temperature of the target 231, the cooling water e cools the target 231 via the target base 232 and the bonding portion 233. The temperature of the cooling water e rises by the amount of heat absorbed from the target 231. Therefore, when film formation begins, the temperature of the cooling water e rises. In other words, when film formation begins, the temperature Te_out of the cooling water e after cooling rises. For example, as shown by the predetermined time T1 in FIG. 4, the cooling water in / out temperature difference gradually increases with the film formation time.

[0062] At the beginning of the film formation process, the amount of heat obtained from the heat source 234 (amount of heat input to the target 231) is greater than the amount of cooling by the cooling water e (amount of heat exhausted by the cooling water e). Therefore, the temperature of the target 231 increases. As the temperature of the target 231 increases, the amount of cooling by the cooling water e also increases. When the target 231 reaches a certain temperature, the amount of heat input to the target 231 and the amount of heat exhausted by the cooling water e are balanced. In other words, the target 231 reaches a steady state. As a result, the temperature difference between the inlet and outlet cooling water becomes constant.

[0063] FIG. 5 is a graph showing the cooling water in / out temperature difference indicating that the target 231 has reached a steady state after steady-state operation over a certain period of time. FIG. 5 also shows the cooling water in / out temperature difference when film formation (film formation process) is performed continuously for 120 seconds. As shown in FIG. 5, the cooling water in / out temperature difference becomes constant 100 seconds after the start of the film formation process. In other words, the target 231 reaches a steady state 100 seconds after the start of the film formation process. As described above, a short film formation time refers to a case in which the target 231 has not reached a steady state. Therefore, a short film formation time refers to, for example, a case in which film formation is completed within 100 seconds from the start of film formation. Note that the conditions under which the target 231 reaches a steady state vary depending on the material of the target 231, the film formation conditions, etc. Therefore, even if the film formation process has been running for more than 100 seconds, a case in which the target 231 has not reached a steady state is considered a short film formation time.

[0064] When film formation is completed, the plasma is extinguished. Therefore, the heat source 234 is no longer present, and no heat is introduced into the target 231. The cooling water e continues to cool the target 231 via the target base 232 and the bonding portion 233. Therefore, the temperature of the target 231 decreases due to the heat discharged by the cooling water e. As the temperature of the target 231 decreases, the temperature of the cooling water e after cooling also decreases. In other words, when film formation is completed, the temperature Te_out of the cooling water e decreases. For example, as shown at the predetermined time T2 in FIG. 4, the difference in the cooling water in / out temperatures gradually decreases as time passes from the end of the film formation process.

[0065] The bonding state determination unit 46 compares the calculated change pattern of the in / out temperature difference of the cooling water e with the change pattern of the in / out temperature difference of the cooling water e for a good target to determine the bonding state of the target 231 (S04: bonding state determination step). FIG. 6 is a graph showing the change pattern of the in / out temperature difference of the cooling water e for a good target and a damaged target. Note that a damaged target refers to a target in which peeling has occurred. As shown in the graph in the boxed portion of FIG. 6, at predetermined times T1 and T2, the slope of the temperature curve for the good target is large, while the slope of the temperature curve for the damaged target is small. The bonding state determination unit 46 calculates the slope of the temperature curve for the calculated in / out temperature difference and calculates how closely the slope resembles the slope for the good target. If the difference in slope is within a certain value, it is determined that no significant peeling that would lead to the detachment of the target 231 has occurred.

[0066] Here, we consider a case where steady-state operation is performed for a certain period of time and the target 231 reaches a steady state. For example, the case where the target 231 reaches a steady state refers to the state of the in / out temperature difference of the cooling water e 100 seconds after the start of the film formation process in FIG. 5. If peeling occurs at the bonding portion 233 at this time, the thermal resistance of the bonding portion 233 increases, causing a temporary decrease in the in / out temperature difference of the cooling water e. When steady-state operation is performed for a certain period of time, peeling of the bonding portion 233 can be detected by using the temporarily decreased temperature as a threshold value.

[0067] However, it is difficult to set a threshold value immediately after the start of operation or when the film formation time is short even during steady operation. For example, as shown in Figure 4, when the film formation time is short even during steady operation, the in / out temperature difference of the cooling water e decreases from the end of one film formation to the start of the next film formation. It is difficult to distinguish whether the decrease in the in / out temperature difference of the cooling water e is due to the end of film formation or peeling of the bonding portion 233 using the method of setting a threshold value.

[0068] [1-3. Effects] (1) The film formation apparatus 1 of this embodiment includes a chamber 2 into which the workpiece W is carried, a target 231 installed in the chamber 2, a target base 232 that holds the target 231 on one side, temperature detection units (temperature sensors 237b, 238b) that detect the temperature of the target 231 and / or the target base 232 at a predetermined time T2 after the end of the film formation process or at a predetermined time T1 from the start of the film formation process after a specific time Tsp has elapsed since the end of the film formation process, a calculation unit 45 that calculates a change in temperature over time over the predetermined time based on the detected temperature of the target 231 and / or the target base 232, and a bonding state determination unit 46 that determines the bonding state of the target 231 based on the change in temperature over time over the predetermined time.

[0069] In this embodiment, the bonding state of the target 231 is determined based on the pattern of temperature change of the target 231 over the predetermined times T1 and T2. That is, the state of thermal resistance of the bonding part 233 that fixes the target 231 and the target base 232 is indirectly monitored by the temperature of the target 231. When peeling occurs in the target 231, the thermal resistance of the target 231 increases. Furthermore, since peeling is not detected based on the state of the target 231 at a certain time, but based on the pattern of temperature change over a fixed period of time, that is, the predetermined times T1 and T2, it is possible to detect very small peeling in the early stages.

[0070] Furthermore, since very small peeling in the early stages can be detected, information about the bonding state of the target 231 can be managed. For example, information about the bonding state of the target 231 can be recorded on a recording medium such as a barcode, QR code, or IC tag provided in a front-opening unified pod (FOUP). By managing information using a recording medium provided in the FOUP, even if defects such as quality degradation or uneven film thickness of the thin film formed on the workpiece W occur, the cause can be quickly identified and resolved. Furthermore, by managing information about the bonding state of the target 231, it is possible to distinguish between very small peeling in the early stages that does not cause defects and very small peeling in the early stages that does cause defects. Therefore, if very small peeling occurs in the early stages that cause defects, the film forming apparatus 1 can be stopped, thereby improving the yield of the workpiece W.

[0071] If delamination is detected solely based on a change in the state of the target 231, for example, the temperature of the target 231 at a certain time, it is impossible to detect small delaminations of the target 231 caused by melting or peeling of the bonding portion 233 due to some cause. In such cases, the delamination of the target 231 often progresses gradually over the course of continued use of the target 231, ultimately resulting in the target 231 falling off. Therefore, even if a problem is identified when the target 231 falls off, it is often impossible to identify the true cause of the delamination. In this embodiment, the state of the target 231 being monitored is compared with the measurement results of a good target over a certain period of time, i.e., the pattern of temperature change. Delamination of the target 231 occurs due to melting or stress-induced peeling of the bonding portion 233, and the thermal resistance of the target 231 increases. The bonding state of the target 231 is detected using the difference in temperature change over a predetermined period of time T1 (T2) caused by the increase in the thermal resistance of the target 231, making it possible to detect small delaminations before the target 231 falls off. Furthermore, since it is possible to detect small peelings before the target 231 falls off, it is possible to predict the timing for replacing the target 231 and notify the user when maintenance is required.

[0072] Furthermore, peeling of the target 231 may occur even though the target 231 is not heated to a temperature at which the bonding portion 233 melts. This is thought to be caused by stress generated by a difference in thermal expansion between the target 231 and the bonding portion 233, or between the target base 232 and the bonding portion 233. In this embodiment, when peeling of the target 231 occurs, it appears as a temperature change of the target 231 over the predetermined times T1 and T2, so peeling due to stress can also be detected.

[0073] Furthermore, in this embodiment, the temperature change patterns of a non-defective target and the target 231 are compared. Therefore, even when it is difficult to determine a threshold value for the measured value (for example, immediately after the start of operation or when the deposition time is short even during steady-state operation), it is possible to detect small peeling before the target 231 falls off. Furthermore, because it is possible to determine whether the peeling occurred within the predetermined times T1 and T2, it becomes easier to identify the true cause that led to the start of peeling of the target 231.

[0074] (2) In this embodiment, the cooling plate 235 is in contact with the other surface of the target base 232 and is provided with a flow path 235f for the cooling water e. The temperature detection unit is temperature sensors 237b, 238b provided in the water supply unit 237 and the water drain unit 238 connected to the flow path 235f of the cooling plate 235. The temperature detection unit detects the temperature of the target 231 and / or the target base 232 as temperatures before and after the cooling of the cooling water e (temperature Te_in and temperature Te_out). The calculation unit 45 calculates the change over time in the temperature difference before and after the cooling of the cooling water e at the specified times T1 and T2. The bonding state determination unit 46 determines the bonding state of the target 231 based on the change over time in the temperature difference before and after the cooling of the cooling water e at the specified times T1 and T2.

[0075] The temperature of the target 231 is not measured directly, but is measured indirectly by measuring the temperatures Te_in and Te_out of the cooling water e. Therefore, there is no need to attach new temperature measuring devices to the target 231 or the target base 232. This makes it possible to prevent measurement errors caused by the attachment of temperature measuring devices, and the system can be introduced without burdening the user with the installation.

[0076] [1-4. Modifications] (1) In the above embodiment, the bonding state determination unit 46 detected the bonding state of the target 231 by comparing the slope of the cooling water in / out temperature difference during the predetermined times T1 and T2 with the slope of the cooling water in / out temperature difference for a non-defective target. By determining the bonding state of the target twice, during the predetermined times T1 and T2, it becomes easier to narrow down the period during which peeling of the target 231 began and identify the true cause of the peeling. Alternatively, instead of determining the bonding state of the target 231 during both the predetermined times T1 and T2, the bonding state may be determined only during the predetermined time T1 or only during the predetermined time T2. Depending on the film formation conditions and the type of target, a difference between a non-defective target and a damaged target may appear during only one of the predetermined times T1 and T2. In such a case, the bonding state may be determined during only one of the predetermined times T1 and T2, rather than during both the predetermined times T1 and T2. In particular, by determining the bonding state at the predetermined time T1, the bonding state of the target 231 can be determined immediately after the start of the film formation process. Therefore, if a small peeling of the target 231 before it falls off is detected, the film formation process can be stopped immediately. Therefore, it is possible to prevent the target 231 from falling off during the film formation process.

[0077] Furthermore, during S01 and S02, the control device 4 may also store whether or not the power supply device 24 applied a voltage to the target 231 relative to the elapsed time t. One method for the control device 4 to recognize the "end of the film formation process" and the "start of the film formation process" after a specific time Tsp has elapsed since the end of the film formation process is to monitor the interval between voltage applications by the power supply device 24 to the target 231. FIG. 8A is a graph showing the change pattern of the in / out temperature difference of the cooling water e between a good target and a damaged target. FIG. 8B is a graph showing the ON / OFF of the voltage applied by the power supply device 24, corresponding to the change pattern of the in / out temperature difference of the cooling water e in FIG. 8A. For example, as shown in FIG. 8B, it may be determined whether the time (OFF time) between the stop of application of a DC voltage to the target 231 by the power supply device 24 and the start of application of a DC voltage to the next target 231 has elapsed for a specific time Tsp or more. In this embodiment, the specific time Tsp is 180 seconds, and therefore, if 180 seconds or more have passed since the application of the DC voltage to the target 231 was stopped, the end of the film formation process is determined to be the end of the film formation process immediately before the specific time Tsp has passed. Similarly, if film formation starts after the specific time Tsp (180 seconds) or more has passed since the application of the DC voltage to the target 231 was stopped, the start of the film formation process is determined.

[0078] In addition, instead of the gradient of the cooling water in / out temperature difference at the specified times T1 and T2, a threshold value (first threshold value) may be set for the difference when comparing the in / out temperature difference of the cooling water e of the good target with the in / out temperature difference of the cooling water e of the damaged target, and the bonding state of the target 231 may be determined by checking whether the time during which the difference when compared remains greater than or equal to the first threshold value continues for a specified time or longer.

[0079] For example, at a predetermined time T1, the value of the in / out temperature difference of the cooling water e in the good target becomes larger than the value of the in / out temperature difference of the cooling water e in the damaged target. Therefore, the difference between the in / out temperature difference of the cooling water e in the good target and the in / out temperature difference of the cooling water e in the damaged target is calculated. If the calculated difference remains equal to or greater than a first threshold value for a predetermined time or longer, it may be determined that small separation of the target 231 has occurred before it falls off.

[0080] Furthermore, at the predetermined time T2, the value of the in / out temperature difference of the cooling water e in the good target becomes smaller than the value of the in / out temperature difference of the cooling water e in the damaged target. Therefore, the difference between the in / out temperature difference of the cooling water e in the good target and the in / out temperature difference of the cooling water e in the damaged target is calculated. If the calculated difference remains equal to or greater than a first threshold value for a predetermined time or longer, it may be determined that small separation of the target 231 has occurred before it falls off. Note that different first threshold values ​​may be used for the predetermined time T1 and the predetermined time T2.

[0081] (2) In the above embodiment, the bonding state determination unit 46 compares the calculated in / out temperature difference of the cooling water e of the target 231 with the in / out temperature difference of the cooling water e of a non-defective target to determine the bonding state of the target 231. However, the method for determining the bonding state of the target by the bonding state determination unit 46 is not limited to the above.

[0082] For example, as shown in FIG. 9 , a flow meter 53 is provided to measure the flow rate of the cooling water e flowing through the flow path 235 f, and the inlet temperature (temperature Te_in), outlet temperature (temperature Te_out), and flow rate of the cooling water e are measured. The amount of waste heat J of the target 231 is calculated from the measured inlet temperature (temperature Te_in), outlet temperature (temperature Te_out), and flow rate of the cooling water e. The integrated value (integrated amount of waste heat G) of the amount of waste heat J for a predetermined time T1 and / or a predetermined time T2 may be calculated from the calculated amount of waste heat J, and the bonding condition may be determined by comparing it with the integrated value for the same time of a non-defective target. In this embodiment, the flow meter 53 is provided in the water supply unit 237, but it may also be provided in the drainage unit 238, or in both the water supply unit 237 and the drainage unit 238.

[0083] A case where the bonding state of the target 231 is determined from the integrated value of the exhaust heat amount J over a predetermined time T2 will be described with reference to FIGS. 9, 10, and 11. The memory unit 44a stores the temperature Te_in and temperature Te_out of the cooling water e, as well as the flow rate of the cooling water e from the flow meter 53. The calculation unit 45 has an exhaust heat amount calculation unit 451 and an exhaust heat amount integration unit 452. The exhaust heat amount calculation unit 451 calculates the exhaust heat amount J of the target 231 over the elapsed time t from the temperature change of the target 231 over the predetermined time T2 calculated from the temperature Te_in and temperature Te_out of the cooling water e at the predetermined time T2 and the flow rate of the cooling water e. Furthermore, the exhaust heat amount integration unit 452 integrates the exhaust heat amount J to calculate the integrated exhaust heat amount G for the elapsed time t, and calculates the integrated exhaust heat amount GT2 (GT1) over the predetermined time T2 (T1). That is, the exhaust heat amount calculation unit 451 calculates the change over time in the integrated exhaust heat amount G for the predetermined time T1 and / or the predetermined time T2.

[0084] The reference value storage unit 43a pre-stores the cumulative exhaust heat amount GT2 (GT1) of the non-defective target during the predetermined time T2 (T1). The bonding state determination unit 46a determines the bonding state by comparing the cumulative exhaust heat amount GT2 (GT1) of the non-defective target during the predetermined time T2 (T1) with the cumulative exhaust heat amount GT2 (GT1) calculated from the target 231. In other words, the bonding state determination unit 46a determines the bonding state of the target 231 based on a change over time in the cumulative exhaust heat amount G during the predetermined time T1 and / or the predetermined time T2.

[0085] 10 is a graph showing the change pattern of the accumulated waste heat amount GT2 of a non-defective target and a damaged target over a predetermined time T2. In FIG. 10, the start time tT2b of the predetermined time T2 is set to zero, and the end time tT2e of the predetermined time T2 is set to 180 seconds. At the start time tT2b of the predetermined time T2, the accumulated waste heat amount GT2 is set to the same value as the waste heat amount J at the start time tT2b of the predetermined time T2. In this embodiment, the accumulated waste heat amount GT2 over the predetermined time T2 for determining the bonding state is set to the accumulated waste heat amount GT2 at the end time tT2e of the predetermined time T2. When determining the bonding state of the target 231 from the accumulated waste heat amount GT2 over the predetermined time T2, the waste heat amount J over the predetermined time T2 is integrated to calculate the accumulated waste heat amount GT2 over the predetermined time T2. In this case, the value of the integrated waste heat quantity GT2 when large peeling occurs is obtained in advance by experiment, and a smaller integrated waste heat quantity G value with a margin than that value is set as a value that serves as an indicator of small peeling before the target 231 falls off. In this way, if peeling is detected when the value that serves as an indicator of small peeling before the target 231 falls off is reached, it is possible to prevent the target 231 from falling off.

[0086] The bonding state determination unit 46a determines the bonding state by comparing the cumulative waste heat amount GT2 of the non-defective target for a predetermined time T2, which has been stored in advance in the reference value storage unit 43a, with the cumulative waste heat amount GT2 calculated from the target 231. For example, peeling of the target 231 may be detected based on whether the difference between the cumulative waste heat amount GT2 calculated from the target 231 and the cumulative waste heat amount GT2 of the non-defective target is higher or lower than a threshold value (second threshold value). The same process may be performed for the predetermined time T1. However, even if the material of the target 231 is the same, if the film formation conditions are different, the cumulative waste heat amount GT2 will also differ. It is preferable to perform the determination using the above method when the film formation conditions are the same.

[0087] (3) Alternatively, instead of directly comparing the cumulative waste heat amounts G, the cumulative waste heat amount Gt after a predetermined reference time tc may be used as a reference, and a waste heat ratio, which is the relative value of the cumulative waste heat amount G for each elapsed time t to the cumulative waste heat amount Gt, may be calculated, and the bonding state may be determined based on this waste heat ratio. As shown in FIG. 12 , the calculation unit 45 further includes a relative cumulative waste heat amount calculation unit 454. The relative cumulative waste heat amount calculation unit 454 sets the cumulative waste heat amount Gt after 180 seconds have elapsed since the end of the film formation process to "1" and calculates the relative value (waste heat ratio) of the cumulative waste heat amount G with respect to the elapsed time t from the end of the film formation process (the elapsed time t from the stop of heat input). In other words, the relative cumulative waste heat amount calculation unit 454 uses the cumulative waste heat amount Gt after the predetermined time tc calculated by the waste heat amount calculation unit 452 as a reference, and calculates the relative value of the cumulative waste heat amount G with respect to the elapsed time t.

[0088] 13 is a graph showing the heat release ratio versus time t elapsed since heat input was stopped. In FIG. 13, the solid line shows the change in the heat release ratio versus time t elapsed since heat input was stopped for a good target, and the dotted line shows the change in the heat release ratio versus time t elapsed since heat input was stopped for a target 231 (damaged target) in which peeling has occurred at the bonding portion 233. It can be seen that in the case of a good target, the heat release ratio exceeds 0.8 30 seconds after the film formation process (heat input stop), whereas in the case of a target 231 in which peeling has occurred at the bonding portion 233, the heat release ratio value 30 seconds after the film formation process (heat input stop) is below 0.8.

[0089] For example, the heat release ratio 30 seconds after the film formation process (heat input stop) may be calculated, and peeling of the target 231 may be detected based on whether the calculated value is higher or lower than 0.8 (second threshold value). The second threshold value may be determined, for example, by experimenting in advance with the heat release ratio 30 seconds after the film formation process (heat input stop) in the case of large peeling, and a value larger than that value with a margin may be set as a value that serves as an indicator of small peeling. In this way, if peeling is detected when the value reaches the indicator of small peeling, it is possible to prevent the target 231 from falling off.

[0090] In this modification, the bonding state determination unit 46a determines the bonding state of the target 231 based on the relative value calculated by the relative integrated waste heat amount calculation unit 454. Because the bonding state is determined based on the waste heat ratio, it is possible to detect peeling by comparing it with the second threshold value. This reduces the effort required to create a program for determining the bonding state. Furthermore, even when the film formation conditions are different and the integrated waste heat amount GT2 of the non-defective target and the integrated waste heat amount GT2 of the target 231 differ in value, comparison based on the waste heat ratio (relative value) is possible. This makes it easier to compare the integrated waste heat amounts G of targets with different film formation conditions.

[0091] [2. Second embodiment] [2-1. Configuration] A second embodiment of the present invention will be described with reference to the drawings. The same components as those in the first embodiment are designated by the same reference numerals and will not be described again.

[0092] 14 , the film forming apparatus 1 of this embodiment includes a temperature sensor 231a that detects the temperature TTGT of the target 231, which corresponds to a temperature detection unit, and a temperature sensor 232a that detects the temperature Tbase of the target base 232. Thermocouples can be used as the temperature sensors 231a and 232a. The temperature sensors 231a and 232a detect the temperatures of the target 231 and the target base 232 at a predetermined time T2 after the end of the film forming process or at a predetermined time T1 from the start of the film forming process after a specific time Tsp has elapsed since the end of the film forming process. Note that the temperature TTGT of the target 231 may also be referred to as temperature TTGT, and the temperature Tbase of the target base 232 may also be referred to as temperature Tbase.

[0093] The configuration of the control device 4 will be described with reference to Fig. 15, which is a virtual functional block diagram. The control device 4 has a film formation processing unit 41, a reference temperature storage unit 43b, a memory unit 44b, a calculation unit 45b, a bonding state determination unit 46b, a notification unit 47, and an input / output control unit 48. Note that the control device 4 is connected to an input device 61 and an output device 62, similar to the first embodiment.

[0094] The reference temperature storage unit 43b calculates and stores the process by which the target 231 and the target base 232 of a non-defective target decrease in temperature from a state in which the heat input and the heat output are balanced (steady state) to a state in which the heat input to the non-defective target has ceased. For example, the reference temperature storage unit 43b stores the temperature Tbase of the target base 232 relative to the temperature TTGT of the target 231 for each elapsed time t from the end of the film formation process of the non-defective target until 300 seconds have elapsed.

[0095] FIG. 16 is a graph showing a simulation of the correlation between the temperature TTGT of the target 231 and the temperature Tbase of the target base 232, which change over time, after a film formation process using a Cr target measuring φ150 mm and t10 mm. In other words, FIG. 16 is a graph showing a simulation of the correlation between the temperature TTGT of the target 231 and the temperature Tbase of the target base 232 at a predetermined time T2. In FIG. 16, the temperature TTGT of the target 231 is plotted on the X-axis, and the temperature Tbase of the target base 232 is plotted on the Y-axis. The solid line shows the results of a simulation performed by changing the applied power and the flow rate of cooling water e, in which the temperature Tbase of the target base 232 was plotted against the temperature TTGT of the target 231 of a non-delaminated, non-delaminated target. The dotted line shows the temperature Tbase of the target base 232 against the temperature TTGT of the target 231, assuming a target 231 with increased thermal resistance due to delamination. Here too, the simulation was carried out by changing the applied power and the flow rate of the cooling water e.

[0096] 16 , in the plot assuming delamination (dotted line), it can be seen that the temperature TTGT of the target 231 is higher than the temperature Tbase of the target base 232 compared to a good target at any flow rate of cooling water e. This is thought to be because the target 231 where delamination has occurred has increased thermal resistance due to the delamination, making it difficult to transfer heat input from the heat source 234 to the target base 232. In other words, by determining the slope of the temperature change from the plot of the temperature Tbase of the target base 232 against the temperature TTGT of the target 231 that changes over time during a predetermined time T2 after the film formation process and comparing it with that of a good target, it is possible to determine the bonding state of the target 231.

[0097] The memory unit 44b stores the temperature TTGT of the target 231 and the temperature Tbase of the target base 232 detected by the temperature sensor 231a and the temperature sensor 232a. When film formation starts, the temperature TTGT of the target 231 and the temperature Tbase of the target base 232 are transmitted to the control device 4. The memory unit 44b stores the temperature TTGT of the target 231 and the temperature Tbase of the target base 232, which change over time during the predetermined times T1 and T2. The memory unit 44b may also store the temperature TTGT of the target 231 and the temperature Tbase of the target base 232 from the start of the film formation process to the end of the film formation process. Alternatively, the memory unit 44b may store the temperature TTGT of the target 231 and the temperature Tbase of the target base 232 while the film formation apparatus 1 is operating.

[0098] The calculation unit 45b calculates the temperature Tbase of the target base 232 relative to the temperature TTGT of the target 231 from the temperature TTGT and temperature Tbase stored in the memory unit 44b. That is, the calculation unit 45b correlates the temperature Tbase of the target base 232 with the temperature TTGT of the target 231, which changes over time during the predetermined time T2 (T1). This allows the value of the temperature Tbase of the target base 232 relative to the temperature TTGT of the target 231 during the predetermined time T2 (T1) to be obtained. The value of the temperature Tbase of the target base 232 relative to the temperature TTGT of the target 231 during the predetermined time T2 (T1) is also included in the change in temperature over time during the predetermined time T2 (T1). The temperature Tbase of the target base 232 relative to the temperature TTGT of the target 231 for each elapsed time t calculated by the calculation unit 45b may be obtained at either or both of the predetermined time T1 and the predetermined time T2, but for the sake of explanation below, the temperature Tbase of the target base 232 relative to the temperature TTGT of the target 231 at the predetermined time T2 (300 seconds after the end of the film formation process) will be described as being calculated.

[0099] The bonding state determination unit 46b determines the bonding state of the target 231 based on the correlation between the temperature Tbase of the target base 232 and the temperature TTGT of the target 231, which changes over time during the predetermined time T2. In other words, the bonding state determination unit 46b is a determination unit that determines the bonding state of the target by comparing the temperature Tbase of the target base 232 and the temperature TTGT of the target 231 for each elapsed time t during the predetermined time T2 calculated from the target 231 with the temperature Tbase of the target base 232 and the temperature TTGT of the target 231 for each elapsed time t during the predetermined time T2 of a non-defective target stored in the reference temperature storage unit 43b.

[0100] [2-2. Operation] Next, the operation of the film deposition apparatus 1 and the film deposition method according to this embodiment will be described with reference to FIG.

[0101] When the film formation process is completed (S21: film formation process completion step), the temperature TTGT and the temperature Tbase are stored (S22: temperature detection step). The temperatures TTGT and Tbase detected by the temperature sensors 231a and 232a are periodically transmitted to the control device 4. The storage unit 44 stores the temperatures TTGT and Tbase.

[0102] The calculation unit 45 correlates the temperature Tbase with the temperature TTGT at the predetermined time T2 (S23: calculation step). That is, during film formation, heat is input to and exhaust from the target 231, but once the film formation process is completed, the target 231 is no longer heated, and the target 231 and the target base 232 gradually decrease in temperature. The calculation unit 45 arranges the temperature Tbase and the temperature TTGT for each elapsed time t, and obtains a pattern of change in the temperature Tbase with respect to the temperature TTGT at the predetermined time T2.

[0103] The bonding state determination unit 46 compares the pattern of change in the temperature Tbase of the target base 232 relative to the calculated temperature TTGT of the target 231 with the pattern of change in the temperature Tbase of the target base 232 relative to the temperature TTGT of the target 231 of a non-defective target, and determines the bonding state of the target 231 (S24: bonding state determination step). FIG. 18 is a graph showing the correlation between the temperature TTGT of the target 231 and the temperature Tbase of the target base 232. FIG. 18 shows the temperature Tbase of the target base 232 relative to the temperature TTGT of the target 231 for each target 231 in a different state. Comparing FIG. 18 with FIG. 16, the pattern of change in the temperature Tbase of the target base 232 relative to the temperature TTGT of the target 231 is the same. From this, it is considered that the temperature changes of the target 231 and the target base 232 are caused by an increase in the thermal resistance of the target 231. Furthermore, as shown in the graph of FIG. 18, in the case of a non-defective target, the absolute value of the gradient of the temperature curve in the graph is large, whereas in the case of a damaged target, the absolute value of the gradient of the temperature curve is small.

[0104] The bonding condition determination unit 46b calculates the slope of the temperature Tbase of the target base 232 relative to the temperature TTGT of the target 231 and calculates how closely the slope resembles the slope of a good target. If the difference in slope is within a certain value, it is determined that no delamination has occurred. For example, the absolute value of the "temperature curve slope" for large delamination is determined in advance through experiments, and a value that has a margin greater than that value and is larger when compared in absolute value is set as a value that indicates small delamination. By doing so, if delamination is detected when the value that indicates small delamination is reached, it is possible to prevent the target 231 from falling off. Alternatively, the difference between the value that indicates small delamination and the absolute value of the slope of the temperature curve of a good target may be calculated, and if the difference in slope is within this value, it may be determined that no delamination has occurred. Although a method for calculating the gradient of the temperature Tbase of the target base 232 relative to the temperature TTGT of the target 231 at a predetermined time T2 has been described, the bonding state determination unit 46b can also determine the bonding state of the target 231 by calculating the gradient of the temperature Tbase of the target base 232 relative to the temperature TTGT of the target 231 at a predetermined time T1.

[0105] [2-3. Effects] (1) In this embodiment, the bonding state of the target 231 is determined based on the correlation between the temperature Tbase and the temperature TTGT, which change over time during the predetermined times T1 and T2. That is, the state of the thermal resistance of the bonding part 233, which fixes the target 231 and the target base 232, is monitored by directly measuring the temperature Tbase and the temperature TTGT. When peeling occurs in the target 231, the thermal resistance of the target 231 increases. Therefore, as in the first embodiment, peeling is not detected based on the state of the target 231 at a certain time, but rather the bonding state is determined based on the correlation between the temperature Tbase and the temperature TTGT, which change over time during a fixed period of time, i.e., the predetermined times T1 and T2, and therefore it is possible to detect very small peeling in the early stages.

[0106] Furthermore, because even the smallest peeling can be detected in the early stages, information about the bonding state of the target 231 can be recorded on a recording medium provided in the FOUP, and the information about the bonding state of the target 231 can be managed. Therefore, even if problems such as deterioration in the quality of the film formed on the workpiece W or uneven film thickness occur, the cause can be quickly identified and resolved. Furthermore, since the quality of the thin film formed on the workpiece W can be managed, the yield of the workpiece W can be improved. Furthermore, by managing the information about the bonding state of the target 231, it is possible to predict when to replace the target 231 and notify the user when maintenance is required.

[0107] [3. Other Embodiments] While the embodiments of the present invention and modifications of each part have been described above, these embodiments and modifications of each part are presented as examples and are not intended to limit the scope of the invention. These novel embodiments described above can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and modifications are included within the scope and spirit of the invention, and are also included in the invention described in the claims.

[0108] REFERENCE SIGNS LIST 1 Film forming apparatus 2 Chamber 4 Control device 20 Loading / unloading port 21 Stage 22 Shaft 23 Sputtering source 231 Target 231a Temperature sensor 232 Target base 232a Temperature sensor 233 Bonding section 234 Heat source 235 Cooling plate 235a Sealing material 235b Groove 235b1 Inlet 235b2 Outlet 235c Flange 235d Water supply port 235e Discharge port 235f Flow path 236 Anode section 236a TS distance adjustment section 236a1 Thick section 236a2 Flange 236b Anode ring 237 Water supply section 237b Temperature sensor 238 Drain section 238b Temperature sensor 239 Magnet section 239a Magnet 239b Motor 24 Power supply device 25 Exhaust device 26 Pressure gauge 27 Sputtering gas inlet 271a Argon gas inlet 271b Flow rate controller 41 Film formation processing unit 43, 43b Reference temperature storage unit 43a Reference value storage unit 44, 44a, 44b Memory unit 45, 45b Calculation unit 451 Exhaust heat amount calculation unit 452 Exhaust heat amount accumulation unit 454 Relative accumulated exhaust heat amount calculation unit 46, 46a, 46b Bonding state determination unit 47 Notification unit 48 Input / output control unit 53 Flow meter 61 Input device 62 Output device J Exhaust heat amount G, Gt, GT2 Accumulated exhaust heat amount t Elapsed time T1, T2 Predetermined time Tbase Target base temperature Tsp Specific time TTGT Target temperature Te Cooling water temperature W Work

Claims

1. A film formation apparatus for forming a film on a workpiece using plasma, comprising: an airtight container into which the workpiece is carried; a target installed within the airtight container; a target base for holding the target on one side; a temperature detection unit for detecting the temperature of the target and / or the target base at a predetermined time after the end of a film formation process or at a predetermined time from the start of the film formation process after a specific time has elapsed since the end of the film formation process; a calculation unit for calculating a change in temperature over time over the predetermined time based on the detected temperature of the target and / or the target base; and a bonding state determination unit for determining the bonding state of the target based on the change in temperature over time over the predetermined time.

2. A film forming apparatus as described in claim 1, further comprising a cooling plate in contact with the other surface of the target base and having a flow path for cooling water, the temperature detection unit being a temperature sensor provided in a water supply unit and a water drain unit connected to the flow path of the cooling plate, the temperature detection unit detecting the temperature of the target and / or the target base as the temperature before and after cooling of the cooling water, the calculation unit calculating the change over time in the temperature difference between before and after cooling of the cooling water at a predetermined time, and the bonding state determination unit determining the bonding state of the target based on the change over time in the temperature difference between before and after cooling of the cooling water at the predetermined time.

3. A film forming apparatus as described in claim 2, further comprising a flow meter for detecting the flow rate of cooling water flowing through the flow path, wherein the calculation unit comprises: an exhaust heat amount calculation unit for calculating the amount of exhaust heat from the target over an elapsed time from the change in temperature of the target over a predetermined time and the flow rate of the cooling water; and an exhaust heat amount accumulation unit for accumulating the amount of exhaust heat and calculating the accumulated amount of exhaust heat over the predetermined time, wherein the calculation unit calculates the change over time in the accumulated amount of exhaust heat over the predetermined time, and the bonding state determination unit determines the bonding state of the target based on the change over time in the accumulated amount of exhaust heat over the predetermined time.

4. The film forming apparatus of claim 3, wherein the calculation unit has a relative integrated exhaust heat calculation unit that calculates a relative value of the integrated exhaust heat with respect to the elapsed time based on the integrated exhaust heat after a predetermined time has elapsed calculated by the exhaust heat calculation unit, and the bonding condition determination unit determines the bonding condition of the target based on the relative value calculated by the relative integrated exhaust heat calculation unit.

5. The film formation apparatus of claim 1, wherein the temperature detection unit detects the temperatures of the target and the target base at a predetermined time after the end of the film formation process or at a predetermined time from the start of the film formation process after a specific time has elapsed since the end of the film formation process, the calculation unit correlates the temperature of the target base with the temperature of the target that changes over time during the predetermined time, and the bonding state determination unit determines the bonding state of the target based on the correlation between the temperature of the target that changes over time and the temperature of the target base.

6. A method for detecting a bonding state of a target in a film formation apparatus that forms a film on a workpiece using plasma, comprising: a temperature detection step for detecting the temperature of the target and / or the target base at a predetermined time after the end of the film formation process or at a predetermined time from the start of the film formation process after a specific time has elapsed since the end of the film formation process; a calculation step for calculating a change in temperature over time over the predetermined time based on the detected temperatures of the target and / or the target base; and a bonding state determination step for determining the bonding state of the target based on the change in temperature over time.

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