JP5719235B2 - Sputtering source end detection mechanism and sputtering apparatus - Google Patents

Description

  The present invention relates to a sputter source end detection mechanism that detects a sputter source before it is consumed and reaches the end, and a sputter apparatus including the sputter source end detection mechanism.

  Sputtering apparatuses such as a magnetron sputtering apparatus and an ion beam sputtering apparatus are widely used in the manufacture of semiconductor devices and the like as apparatuses for forming a thin film of metal or the like with high film thickness accuracy. In addition to the target object whose surface is coated with a film, a sputtering source (target) serving as a film material is placed in the processing chamber of the sputtering apparatus. Depending on the type of sputtering device, etc., the sputtering source is a plate with a thickness of several to several tens of millimeters, and is fixed and placed on the sputtering source holder of the sputtering device so that the surface faces the workpiece. Is done. Sputtering source is scattered by spattering and adheres to the object to be processed, and gradually decreases in the thickness direction to form a film. As a consumable, a new one is processed after a certain number of objects to be processed in the sputtering equipment. To be replaced.

  When the sputtering apparatus is operated in a state where at least a part of the sputter source is lost due to excessive consumption (plate thickness 0), specifically, with a hole opened, the material such as the sputter source holder scatters from the lost region. Since it becomes a foreign material, the sputter source needs to be replaced before it enters such a state. Here, the film formed by the sputtering apparatus is about several hundred nm at the maximum, and less than 1 nm for the thin film, and the consumption of the sputtering source by one process (film formation on one object to be processed) is Very few. Therefore, unlike a target object that is usually replaced with a transfer mechanism provided in a sputtering apparatus and the processing chamber is not opened to the atmosphere (hereinafter simply referred to as opening), the sputtering source is opened manually by opening the processing chamber. It is common to be exchanged. In order to suppress the reduction in productivity due to replacement work as well as the cost of the sputtering source, it is preferable to use the sputtering source until just before it becomes impossible to continue using (plate thickness becomes 0).

  However, depending on the type of sputtering apparatus, many specific parts in the surface of the sputtering source are consumed and thinned locally, and the consumption state of the sputtering source is visually observed from outside the processing chamber. This is difficult, and the thickness of the sputter source is mechanically measured with a measuring instrument such as a caliper, and the process chamber is opened as in the case of replacing the sputter source. Therefore, it is common to empirically set the replacement time of the sputtering source according to the number of processing times of the sputtering apparatus. This time is often set with a considerable margin up to the time required for the replacement of the sputter source, so in order to suppress the cost of the sputter source and the decrease in productivity due to replacement work, It is required to be able to detect that the sputtering source has reached the use limit (termination) without opening the processing chamber.

  As described above, since the sputtering source is locally thinned, the sputtering apparatus has a mechanism for irradiating the surface of the sputtering source with laser light or the like, receiving the reflected light, and monitoring the three-dimensional shape of the surface. Are disclosed (Patent Documents 1 and 2). Specifically, it includes a light source, a photodetector (CCD, etc.), and arithmetic processing means (CPU, etc.). The surface of the sputtering source is scanned by irradiating spot light (light rays) from the light source, and the reflected light is emitted. The three-dimensional shape of the surface of the sputter source is calculated from the position where the reflected light is incident on the photodetector and the irradiation angle of the light beam by the processing means, and the thinnest plate thickness is obtained. Ask. In the sputtering apparatus, the target monitor device disclosed in Patent Document 1 includes a photodetector inside the stage on which the object to be processed is placed, and also irradiates light from the inside of the stage, so that the processing chamber is opened. Without doing so, the three-dimensional shape of the surface of the sputtering source can be calculated. Since the sputtering apparatus disclosed in Patent Document 2 includes the light source and the photodetector arranged outside the region between the object to be processed and the sputtering source, it can be constantly monitored even during the sputtering process. According to these mechanisms, the thinnest plate thickness can be obtained no matter which part of the surface of the sputtering source is thinned, and the sputtering source is consumed in a complicated shape such as a magnetron sputtering device. Suitable for the device.

Japanese Patent No. 2723857 JP-A-8-41638

  The inventions described in Patent Documents 1 and 2 require means for scanning the light beam, a photodetector that can receive the reflected light in a certain wide area and can detect the position where the reflected light is incident, The structure becomes somewhat complicated, and it is difficult to provide the sputtering apparatus particularly in the processing chamber. Furthermore, it requires complicated calculation processing such as calculating the three-dimensional shape of the surface of the sputter source to obtain the thinnest plate thickness, and if it is used continuously until the sputter source is thinner, higher accuracy is required. As a result, the calculation processing time becomes long, and it is difficult to continue the use until, for example, the thinnest is less than 1 μm.

  The present invention has been made in view of the above problems, and can be easily mounted on an existing sputtering apparatus as a simple structure, and is used immediately before opening a hole with a sputtering source attached to the sputtering apparatus. It is an object of the present invention to provide a sputter source end detection mechanism that can be used up to a possible limit (end), and a sputter apparatus equipped with the sputter source end detection mechanism.

  The inventors of the present invention only need to detect the consumption state when the usable limit of the sputtering source is reached, and the sputtering source mainly made of metal is thinned to a thickness of about 50 nm that transmits light. However, since the sputtering process can be continued for a certain number of times, the limit is set when the light emitted from the light source provided on one surface of the sputtering source can be detected from the opposite surface. did. In addition, in the currently used sputtering apparatus, paying attention to the fact that the most consumed part of the sputtering source is fixed, by detecting the transmission of light limited to this part of the sputtering source, It has been found that the sputtering source end detection mechanism has a simple configuration.

That is, the sputtering source end detection mechanism according to the present invention includes a light projecting unit that irradiates light on the back surface of the sputtering source installed in the processing chamber of the sputtering device, and the light projecting unit is consumed by the sputtering device. It arrange | positions in the back side in the site | part of the said sputtering source, It is characterized by the above-mentioned. For this purpose, a recess is formed in either the sputtering source mounting member on which the sputtering source is mounted, that is, the sputtering source holder of the sputtering apparatus or the backing plate of the sputtering source, and the light projecting means is accommodated in the recess. The

  With this configuration, the sputter source end detection mechanism only needs to include a light projecting unit that irradiates light only to the back surface of the portion where the sputter source is consumed. It is only necessary to form and store a concave portion at a specific portion of this, and it becomes an extremely simple configuration, and it can be used until the sputtering source has a thickness that allows light to pass through the thinnest portion.

  Further, it is preferable that the light projecting means is disposed along the back surface of the sputtering source such that the portion accommodated in the concave portion of the sputtering source mounting member is formed in a rod shape or a tubular shape. With such a configuration, it is possible to irradiate more parts on the rear surface of the sputtering source while suppressing the area of the region where the light projecting means is accommodated in the sputtering source holder or the like. The end of the sputtering source can be detected more reliably without hindering the cooling of the sputtering source by the mechanism.

  Moreover, it is preferable that a light projection means is equipped with a light source and the light guide which is connected to the said light source and irradiates light to the back surface of a sputtering source. With this configuration, light is not irradiated directly from the light source to the back surface of the sputtering source, so that the light is evenly irradiated. Moreover, since the part which irradiates light to the back surface of a sputtering source is formed with a light guide, it will be easily processed into a desired shape.

  A sputtering apparatus according to the present invention includes the sputtering source end detection mechanism, and a window through which the surface of the sputtering source installed in the processing chamber can be observed from the outside of the processing chamber is formed on the wall of the processing chamber. It is provided. With this configuration, the light emitted from the light projecting means that passes through the sputtering source can be viewed from the outside of the processing chamber, so that the end of the sputtering source can be detected without opening the processing chamber.

  In addition, a sputtering apparatus according to the present invention includes the sputtering source end detection mechanism and a light receiving unit disposed at a position that does not affect the processing of the object to be processed. A light receiving means is further provided. The light receiving means detects light emitted from the light projecting means that passes through a sputtering source installed in the processing chamber. With this configuration, it is possible to detect the end of the sputtering source without opening the processing chamber.

  Further, when the sputtering apparatus according to the present invention is an ion beam sputtering apparatus that irradiates the surface of the sputtering source with an ion beam, the light projecting means emits light to the back surface in the region of the sputtering source where the ion beam is incident. Irradiation is sufficient. In addition, when the sputtering apparatus according to the present invention is a magnetron sputtering apparatus including a magnetic field generation source, the light projecting means irradiates light on the back surface of the sputtering source in a region where the magnetic field generated from the magnetic field generation source is strong. That's fine. As described above, since the portion where the sputtering source is consumed is determined depending on the type of the sputtering apparatus, in the sputtering source end detection mechanism, the light projecting means can be fixedly arranged in a specific region.

  The sputtering source end detection mechanism according to the present invention can be easily mounted on an existing sputtering apparatus with a simple configuration. The sputtering apparatus according to the present invention can be obtained by diverting an existing sputtering apparatus easily and inexpensively. According to these sputtering apparatuses, since the sputtering source can be used stably until just before the hole is opened, the cost of the sputtering source itself is reduced, and the work frequency required for replacing the sputtering source is reduced. Will improve.

It is the schematic of the ion beam sputtering apparatus applied in 1st Embodiment of this invention. It is a schematic diagram explaining the sputtering source termination | terminus detection mechanism which concerns on 1st Embodiment of this invention, and is corresponded to the enlarged view around the sputtering source shown in FIG. 1, (a) is a perspective view, (b) is a top view, (c) is an AA cross-sectional view of (a) and (b), and (d) is a cross-sectional view corresponding to (c) for explaining a sputtering source end detection mechanism according to a modification. It is the schematic of the magnetron sputtering device applied in 2nd Embodiment of this invention. It is a schematic diagram explaining the sputtering source termination | terminus detection mechanism which concerns on 2nd Embodiment of this invention, is equivalent to the enlarged view of the periphery of a sputtering source shown in FIG. 3, (a) is a perspective view, (b) is a top view, c) is a BB cross-sectional view of (a) and (b) and a CC cross-sectional view of (b).

[First Embodiment]
The sputtering source end detection mechanism according to the first embodiment of the present invention will be described in detail with reference to FIGS. The target end detector (sputter source end detection mechanism) 10 according to the first embodiment of the present invention is provided in the existing ion beam sputtering apparatus 20, and the target (sputter source) T1 has a remaining amount that is difficult to continue using. Detect that. First, the configuration of an ion beam sputtering apparatus (hereinafter, appropriately sputtering apparatus) 20 will be described.

(Ion beam sputtering system)
The sputtering apparatus 20 is a known ion beam sputtering apparatus, and as an example, as shown in FIG. 1, a processing chamber (vacuum processing chamber, chamber) 21 and an exhaust system that exhausts the processing chamber 21 to a vacuum (depressurized) state. 22, an ion source 23 that emits an ion beam to the processing chamber 21, a mass flow controller (MFC) 24 that supplies Ar gas or the like as ion species to the ion source 23, and a target holder (sputter source holder) on which the target T 1 is placed , A sputtering source mounting member) 25, a work stage 27 on which the object to be processed W is mounted, a spare chamber (not shown) connected to the processing chamber 21 via an openable / closable shutter, a spare chamber and a processing chamber. And a transport system (not shown) for taking the workpiece W into and out of the 21 work stages 27.

  The exhaust system 22 includes a vacuum pump, an automatic pressure controller (APC), and the like, and controls the processing chamber 21 to a desired pressure (vacuum state). The ion source 23 includes an ion gun that emits an ion beam toward the target T1, a power source that extracts ions, and the like. The target holder 25 is formed of stainless steel or the like, and the target T1 is fixed and attached to the surface with screws or the like, and the target T1 is cooled by circulating water inside (see FIG. 2C). In the sputtering apparatus 20, the target holder 25 is provided on each of the four surfaces of the base having a quadrangular prism shape (square in FIG. 1), and up to four targets T <b> 1 can be attached. By rotating the base, The desired target T1 can be made to face the workpiece W (work stage 27) and the ion source 23 without opening the processing chamber 21, and can be used as a film material. The work stage 27 places the workpiece W facing the target T1. The preliminary chamber is provided to suppress a change in the vacuum state and atmosphere of the processing chamber 21 when the workpiece W is taken in and out of the processing chamber 21 and is an exhaust gas different from the exhaust system 22 of the processing chamber 21. The pressure is controlled by the system.

The sputtering and film formation by the sputtering apparatus 20 will be described. In the sputtering apparatus 20, a target T1 made of a metal material and an object to be processed W such as a wafer are placed at predetermined positions shown in FIG. An ion beam is irradiated from an ion source 23 in a processing chamber 21 in an Ar atmosphere whose pressure is reduced to about 10 ⁻⁴ Torr by the exhaust system 22 and the mass flow controller 24. The ion beam is incident on the surface of the target T1 with the ion beam bundle inclined by 45 °. When the ions collide with the target T1, the target T1 is scattered in the form of particles from the surface (sputtering). A film made of the same metal material as that of the target T1 is formed by adhering to the surface of the workpiece W placed with the surface facing the T1. The surface of the target T1 refers to a surface (sputtering surface) on the side to be sputtered, and this surface is placed on the target holder 25 so as to face the workpiece W and the back surface is on the surface of the target holder 25. It is cooled by being in contact.

  Therefore, in the ion beam sputtering apparatus 20, the target T <b> 1 is limited to the region where the ions collide and is consumed from the surface. On the surface of the target T1, most of the ions collide with the ion beam incident region (ion beam incident region T1a) in a concentrated manner, and particularly the center thereof, that is, the center of the ion beam bundle (FIGS. 2A and 2C). In FIG. 2 (b), which is indicated by a dash-dot line, the largest number of ions collide at a high speed. Therefore, although the target T1 is consumed in a mortar shape centering on this part, the sputtering rate of the ion beam sputtering apparatus 20 is slow as a whole, so that it becomes a very shallow mortar shape (see FIG. 2C). Since a substantially perfect ion beam bundle is inclined by 45 ° from the ion gun of the ion source 23 and is incident on the target T1, the ion beam incident region T1a is long in the inclination direction as shown in FIG. It becomes oval. For example, in the sputtering apparatus 20 including the ion source 23 that irradiates an ion beam of an ion beam bundle having a diameter of 50 mm, depending on the ability of the sputtering apparatus 20 such as a film formation area (size of the workpiece W), φ6 inch ( A disk-shaped target T1 having a diameter of 150 mm and a thickness of 5 mm is used. Further, in the sputtering apparatus 20, it is assumed that the center of the ion beam bundle reaches the center of the surface of the target T1. Therefore, it can be said that the target T1 is most likely to have a hole at the center in the plane. Note that, since the height position of the surface changes as the target T1 is consumed, the position where the center of the ion beam bundle of the target T1 reaches is strictly shifted, but the distance is sufficiently small, so the position is fixed. Can be considered.

(Target end detector)
As shown in FIGS. 2A to 2C, the target end detector 10 is housed in a groove (concave portion) 25 c formed on the surface of the target holder 25 of the sputtering apparatus 20, and the surface of the target holder 25 is locally localized. A light guide 11 that emits light automatically, and a light source 12 that is connected to the light guide 11 and causes the light guide 11 to emit light. That is, it can be said that the target end detector 10 is a light projecting unit.

  The light guide 11 is formed in a linear shape or a rod shape, and is arranged along the back surface of the target T1, that is, along the surface of the target holder 25, and further extended to the outside of the target holder 25. A light source 12 is connected to one end. The light guide 11 propagates the light from the light source 12 in the length direction, emits the light from the surface of the target holder 25, and irradiates the light toward the back surface of the target T1 attached (FIG. 2 ( c)). Therefore, the light guide 11 is configured to propagate and emit light, and is formed of a material having translucency such as glass, resin, quartz, and the like and having durability in the environment of the processing chamber 21. The shape is preferably a round bar shape, a square bar shape, or a tubular shape, and may be hollow, but an optical fiber having a core / cladding structure is particularly preferable.

  When the light guide 11 is tubular (see FIG. 2C), light travels in the length direction in the tube (core), and thus light is efficiently propagated from the light source 12. And the surface of the light guide 11 in this area | region (light emission part 11a, refer FIG.2 (b)) can be roughened and used so that light may leak from the surface of the target holder 25 (irradiation). On the other hand, the light guide 11 is an area other than the above-described area, that is, an area that does not need to emit light, for example, a light path from the light source 12 to the light emitting part 11a of the light guide 11 (the light guide 11b, see FIG. ), It is preferable to coat the surface so that light does not leak into the processing chamber 21.

  Moreover, in this embodiment, as shown in FIG.2 (b), although the light guide 11 is linearly formed and provided along the straight line which passes along the in-plane center of the target T1, it is not restricted to this. Instead, the back surface of the target holder 25 may be formed along a curved line, or may be bent freely with flexibility by applying or thinning a soft material (decreasing the diameter). It may be formed. However, as will be described later, the light guide 11 is arranged at least immediately below the portion where the thinning of the target T1 is most rapid, that is, the center of the surface. The light guide 11 may be formed by connecting different materials such as a quartz rod to the light emitting part 11a and a flexible optical fiber to the light guide part 11b.

  In order to mount such a target end detector 10, a groove 25 c is formed on the surface of the target holder 25 in accordance with the shape of the light guide 11 in the sputtering apparatus 20. In the description of the configuration of the target end detector 10, “upper and lower” refers to the thickness direction of the target T1 (up and down in FIG. 2C), and “plane” refers to a plane parallel to the surface (sputtering surface) of the target T1. Point to.

  Although the size of the light guide 11 is not particularly defined, a sufficient amount of light can be emitted from the surface of the target holder 25, while the diameter (outside) so as not to hinder the cooling of the target T 1 by the water cooling system of the target holder 25. The diameter is preferably about 1 to several mm. The length of the light guide 11 may be set in accordance with the position of the light source 12 in the sputtering apparatus 20, and in the present embodiment, both ends of the light guide 11 protrude from the target holder 25 in plan view. However, the length of the region accommodated in the groove 25c of the target holder 25 is not specified, and it is predicted that at least the thinning of the target T1 proceeds most rapidly (the thickness that transmits light first is reached first). The light emitting portion 11a is formed so that light can be emitted from directly below the portion to be formed. As described above, such a portion is the in-plane center of the target T1 where the ion beam bundle center of the ion beam reaches, but the target end detector 10 according to the present embodiment applies the light guide 11 to the target T1. As shown in FIGS. 2 (a) and 2 (b), not only one point but also a straight line that includes this point and crosses the ion beam incident region T1a, particularly just below the major axis of the elliptical ion beam incident region T1a. .

  As the light source 12, known light emitting means such as an LED bulb can be applied, depending on the size (diameter) of the light guide 11 and the amount of light emitted from the surface of the target holder 25 (irradiated on the back surface of the target T 1). Specifications such as output and size are selected. In the present embodiment, the light source 12 is provided outside the target holder 25. However, the light source 11 may be stored in the groove 25c of the target holder 25, and the light guide 11 is directly connected to the light source 12 only as the light emitting portion 11a. Is done. The light source 12 in this case is preferably of a size that can be insulated from the target holder 25 and accommodated in the groove 25c, and it is preferable to apply a small-output light emitting means that generates little heat and has a small driving current. Is a chip LED. Alternatively, a linear light source may be formed by a plurality of chip LEDs, and the light guide 11 (light emitting unit 11a) and the light source 12 may be integrated, and a plurality of chip LEDs connected in parallel or in series are accommodated in the groove 25c. Then, both ends are connected to + and − of the power source (see FIG. 2A).

  The power source for driving the light source 12 is provided outside the processing chamber 21 of the sputtering apparatus 20, and can supply current via a commercially available current introduction terminal provided on the wall of the processing chamber 21, for example. In addition, the wiring for supplying current from the power source to the light source 12 is a copper wire that is generally applied for a vacuum processing chamber such as a sputtering apparatus, and is attached so as to connect a ceramic holed insulator for insulation. Apply.

With reference to FIG.2 (c), the usage limit (end) detection method of the target T1 by the target end detector 10 which concerns on this embodiment is demonstrated.
When the target T1 on the target holder 25 is sufficiently thick in the region where the light guide 11 is disposed (immediately above the light guide 11 in FIG. 2C), the metal target T1 is light in the thickness direction. Therefore, the light emitted from the light guide 11 is blocked by the target T1 and cannot be detected on the surface side of the target T1 (upper side in FIG. 2C). As described above, the number of treatments by the sputtering apparatus 20 is accumulated, and the target T1 is thinned into a mortar shape with the center of the ion beam bundle of the ion beam as the deepest portion as described above (FIG. As shown, when a thickness that transmits light directly above the light guide 11, specifically, a portion having a thickness of about 50 nm or less occurs, the light emitted from the light guide 11 is transmitted through this portion of the target T <b> 1. Thus, it is detected on the surface side of the target T1.

  As described above, the light guide 11 is provided immediately below the center of the surface where the thinnest portion (thinnest portion) of the target T1 is likely to be thinned. If the thinnest portion of the light guide 11 is displaced along the length direction of the light guide 11, the thinnest portion can be detected as soon as it reaches a thickness that allows light to pass therethrough. Further, even when the thinnest portion of the target T1 is deviated from directly above the light guide 11, as described above, the target T1 is thinned into a very shallow mortar shape. If the difference is small and the deviation is not large, the thickness is such that light is transmitted directly above the light guide 11 at a time sufficiently earlier than the hole is formed in the thinnest part, and can be detected. In addition, in this embodiment, although it was set as the structure provided with the one light guide 11, it provided two or more in the range which does not prevent the cooling of the target T1, and is adapted to the shift | offset | difference in the surface of the thinning shape of the target T1. It is also possible (see second embodiment below).

  In order to detect light transmitted through the target T1, for example, as shown in FIG. 1, a window 21a in which a glass plate or the like is fitted is provided on the wall of the processing chamber 21 of the sputtering apparatus 20, and the processing chamber 21 (sputtering apparatus 20) is provided. ) Can be detected visually from the outside. Specifically, a window 21a is provided at a position on the wall of the processing chamber 21 where the surface of the target T1 can be observed. Further, in the processing chamber 21, light other than the light emitted from the light guide 11 of the target end detector 10 (external light or the like) is present as much as possible so that the light transmitted through the target T1 is easily detected. . Looking into the processing chamber 21 from the window 21a, it is determined that the target T1 has reached the use limit when a part of the surface of the target T1 attached (one point in the ion beam incident area T1a) appears to shine. Can do.

  Such inspection does not need to be continuously performed (monitored). For example, the inspection may be performed each time before a new workpiece W is loaded onto the work stage 27 and film formation is started. In addition, the inspection may be performed every time a predetermined number of workpieces W are formed. In particular, in the ion beam sputtering apparatus 20, since the thickness of the film to be formed is 200 nm or less, particularly less than 1 nm when the film is thin, the target T1 consumption by one film formation is extremely small. Even if the thickness becomes light transmitting thickness (about 50 nm or less), a certain number of times (depending on film forming conditions) can be processed until the thickness becomes 0 (opens a hole). Therefore, the light guide 11 need not always emit light, and the light source 12 may be turned on manually or automatically during inspection. Further, as shown in FIG. 1, in the sputtering apparatus 20 including a plurality of target holders 25, grooves 25 c are formed in the respective target holders 25, and the target end detector 10 is provided and used (on the object W to be processed). It is preferable that only the light source 12 of the target end detector 10 in the target holder 25 to which the target T1 (facing) is attached is lit.

  As described above, the target end detector according to the first embodiment can be mounted simply by forming a groove having a predetermined shape on the surface of the target holder of the sputtering apparatus, and can be easily applied to an existing ion beam sputtering apparatus. be able to. In particular, the processing chamber only needs to be provided with light projecting means such as a light source and wiring for supplying the driving current thereof, so that the processing (sputtering and film formation) in the sputtering apparatus is not hindered. Can do. Further, since the position where the light guide of the target end detector is provided, that is, the position where the groove of the target holder is formed is set corresponding to the ion beam incident region, it can be said that it is fixed in principle in the sputtering apparatus. The limit of use of the target can be reliably detected with a simple structure. Furthermore, according to the target end detector according to the first embodiment, since the target is detected as a use limit at the stage where the target is thinned to a thickness of about 50 nm that transmits light, the target can be used until just before the hole is opened. The effect of cost reduction and productivity improvement can be obtained.

(Modification)
A target end detector according to a modification of the first embodiment will be described. This modification is provided in the same ion beam sputtering apparatus 20 (see FIG. 1) as in the first embodiment, and detects the use limit of the target T2 made of a sintered material having a low thermal conductivity or an insulating material. Target end detector 10. Such a low thermal conductivity or insulating target T2 is generally bonded in advance to a metal backing plate (sputter source mounting member) 26 such as copper on the back surface thereof, and the backing plate 26 and the target holder 25 together. It is attached. Therefore, even if the light guide 11 is caused to emit light on the surface of the target holder 25, the back surface of the target T2 cannot be irradiated with light. Therefore, the target end detector 10 according to the present modification is used in the following manner. It should be noted that the target end detector 10 according to the present modification is different only in the usage mode, and includes the light guide 11 and the light source 12 connected thereto as in the first embodiment. The material, shape, etc.) are also the same as those in the first embodiment, and the description thereof will be omitted.

  As shown in FIG. 2 (d), the target end detector 10 according to this modification example has the light guide 11 disposed on the surface of the backing plate 26 (the surface to which the back surface of the target T2 is bonded), and the target T2 Irradiate the back of the light. That is, in order to mount the target end detector 10, the backing plate 26 has a groove (concave portion) 26c formed on the surface before the target T2 is bonded, as shown in the enlarged view on the right side of FIG. ing. The shape and in-plane position of the groove 26c are the same as the groove 25c of the target holder 25 in the first embodiment shown in FIG. And since this groove | channel 26c forms a thin hole (gap) between the bonded target T2 and the backing plate 26, in this modification, when the target T2 is attached to the target holder 25, What is necessary is just to insert the light guide 11 through the hole, and thereby the target end detector 10 is mounted. Since the light guide 11 is passed through a narrow hole between the backing plate 26 and the target T2, the shape of the groove 26c on the surface of the backing plate 26 is easy to pass through, such as a straight line, or in the case of a curved line, the light guide 11 The body 11 is preferably configured to be deformable.

  In the target end detector 10 according to this modification, the light guide 11 irradiates the back surface of the target T2 with light as in the first embodiment, so that the use limit (end) detection method of the target T2 and the target T2 are transmitted. The method for detecting the emitted light is the same as in the first embodiment, and a description thereof will be omitted.

  Note that the target made of a light-transmitting material is in a state where the plate thickness is thicker than reaching the use limit, and further, light is transmitted even when attached to the sputtering apparatus 20 (new article). The end detection by 10 is difficult. However, if the material absorbs light to some extent (transmittance is sufficiently low with respect to 100%), it has light receiving means (not shown) that can detect (measure) the amount of light, and light that has passed through the target. The thickness of the target can be measured by the amount of. Therefore, the use limit can be detected by setting the amount of light corresponding to the thickness that is the use limit of the target as the threshold. Alternatively, a light source having a wavelength with low transmittance may be applied to the target material.

  As described above, the target end detector 10 according to the first embodiment including the modification can detect the use limit of the targets T1 and T2 made of any one of the metal material and the insulating material. Further, as shown in FIG. 2 (d), there is no problem even if the target T2 bonded to the backing plate 26 in which the groove 26c is formed is attached to the target holder 25 in which the groove 25c is formed. Accordingly, if the target end detector 10 is configured so that the light guide 11 can be removed from the groove 25c of the target holder 25, the groove 25c for attaching (inserting) the light guide 11 according to the type (material) of the target. 26c can be applied instead.

[Second Embodiment]
The sputtering source end detection mechanism according to the second embodiment of the present invention will be described in detail with reference to FIGS. The target end detector (sputter source end detection mechanism) 10A according to the second embodiment of the present invention is provided in the existing magnetron sputtering apparatus 30, and the target (sputter source) T3 has a residual amount that is difficult to continue using. Detect that. First, the configuration of a magnetron sputtering apparatus (hereinafter referred to as a sputtering apparatus as appropriate) 30 will be described.

(Magnetron sputtering equipment)
The sputtering apparatus 30 is a known planar type magnetron sputtering apparatus, and as an example, as shown in FIG. 3, a processing chamber (vacuum processing chamber, chamber) 31 and exhaust for exhausting the processing chamber 31 to a vacuum (decompression) state. A system 32, a mass flow controller (MFC) 34 that supplies Ar gas or the like as a plasma species, a magnet (magnetic field generation source) 33 that is provided behind the target T3 and generates a magnetic field in the vicinity thereof, and the target T3 are mounted. A target holder (sputter source holder, sputter source mounting member) 35, a work stage 37 on which the object to be processed W is mounted, and a sputtering power source 38 are provided.

  The exhaust system 32 and the work stage 37 have the same configuration as the exhaust system 22 and the work stage 27 of the sputtering apparatus 20 in the first embodiment, respectively. A system (not shown) is provided, and description thereof is omitted. The magnet 33 is a permanent magnet, concentrically (in plan view) in the plane of the target T3, a cylindrical N pole at the center, and an annular S pole surrounding the N pole. It arranges and is constituted (refer to Drawing 4 (a)). The target holder 35 encloses the magnet 33, and similarly to the target holder 25 in the first embodiment, the target T3 is fixed and attached with a screw or the like, and water is circulated inside to cool the target T3 (see FIG. 4 (c)). The sputtering power source 38 connects the anode to the work stage 37 (object W) and the cathode to the target holder 35 (target T3).

The sputtering and film formation by the sputtering apparatus 30 will be described. In the sputtering apparatus 30, a target T3 made of a metal material and an object to be processed W such as a wafer are placed at predetermined positions shown in FIG. A predetermined voltage is applied by the sputtering power supply 38 in the processing chamber 31 in an Ar atmosphere decompressed to about 10 ⁻³ Torr by the exhaust system 32 and the mass flow controller 34. Due to the magnetic field generated by the magnet 33, electrons move spirally along the lines of magnetic force, plasma is generated in the vicinity of the electrons, the target T3 is sputtered from the surface, and adheres to the surface of the workpiece W charged on the anode. Then, a film made of the same metal material as the target T3 is formed (see FIGS. 4A and 4C).

  Therefore, in the magnetron sputtering apparatus 30, the target T3 is sputtered only in the region where the plasma is generated, and the higher the plasma concentration, the faster the progress and the greater the consumption. Since the plasma is generated as the magnetic field is stronger, the plasma is generated along the circle (circumference) formed by the intermediate region between the north and south poles above the magnet 33, that is, the middle line between the north and south poles in plan view. Occurs in a concentrated donut shape (annular). As a result, the target T3 is consumed by reducing the thickness of the same annular region (plasma generation region T3a, see FIGS. 4A and 4B) as the region where the plasma is generated in a plan view by sputtering, In the plasma generation region T3a, it can be said that the hole is most likely to be opened on the circumference of the circle (indicated by a two-dot chain line in FIG. 4B) where the plasma concentration is particularly high. On the circumference of one circle, it is predicted that the thinning will proceed substantially evenly. Therefore, in the target T3, unlike the sputtering by the ion beam sputtering apparatus 20 in the first embodiment, the thinnest portion is predicted by a point. Difficult to do.

  Further, since the magnetron sputtering apparatus 30 has a high sputtering speed, it is required to detect the use limit (termination) more reliably. On the other hand, since the position of the magnet 33 in the sputtering apparatus 30 is fixed, that is, the relative position of the magnet 33 with respect to the target T3 is fixed, the thinnest target predicted for each sputtering apparatus is the same as in the first embodiment. It can be said that the part is fixed. Based on this, the target termination detector according to the second embodiment is configured as follows.

(Target end detector)
The target end detector 10A includes a light projecting unit including a light guide 11 and a light source 12 similar to the target end detector 10 according to the first embodiment, and further, as shown in FIGS. 4 (a) and 4 (c). Since the groove (recess) 35c is formed on the surface of the target holder 35 of the sputtering apparatus 30 and the light guide 11 is accommodated, the cross-sectional structure around the light guide 11 (enlarged view on the right in FIG. 4 (c)) Is substantially the same as the target end detector 10 (see FIG. 2C). In other words, the target end detector 10A is thin to a thickness (about 50 nm or less) at which the light guide 11 irradiates light toward the back surface of the target T3 and the target T3 transmits light immediately above the light guide 11. Then, the light emitted from the light guide 11 is transmitted and detected on the surface (sputtering surface) side of the target T3.

  As described above, in the magnetron sputtering apparatus 30, the thinnest portion of the target T3 is continuously present on the circumference. Therefore, similarly to the target end detector 10 according to the first embodiment, when the light guide 11 is provided in a straight line including the in-plane center of the target T3 (see FIG. 2B), an annular plasma The light guide 11 is provided so as to cross the plasma generation region T3a along the radial direction evenly at two locations in the generation region T3a. When the target T3 is thinned to a thickness that allows light to pass through any part of the light guide 11 directly above, the end can be detected. If the sputtering speed of the target T3 is not biased in the circumferential direction, the target T3 It can be detected before the hole is opened.

  The target end detector 10A according to the present embodiment is configured as follows, so that the end detection accuracy is higher. As shown in FIG. 4B, the target end detector 10A bends the two light guides 11 and 11 to about 90 °, and has a target holder 35 in a shape lacking a crossing intersection in a plan view. To place. Moreover, the light sources 12 and 12 are connected to the light guides 11 and 11, respectively, so that the two light guides 11 and 11 emit light simultaneously. With such a configuration, the light guide 11 is provided so as to evenly cross the plasma generation region T3a along the radial direction at four locations of the annular plasma generation region T3a, and the plasma generation region T3a. The number of observation points increases, and the detection accuracy improves. The number of the light guides 11 and the shape in plan view are not limited thereto, and the light guides 11 may be arranged in a range that does not hinder the cooling of the target T3 by the water cooling system of the target holder 35. In the present embodiment, the light sources 12 and 12 are connected to the light guides 11 and 11, respectively. However, one light source 12 is provided via, for example, an optical fiber (the light guide unit 11b (see FIG. 2B)). Two or more light guides 11 may emit light.

  In order to detect the light transmitted through the target T3, a window is provided in the processing chamber 31 of the sputtering apparatus 30 to detect light from outside the processing chamber 31, as in the first embodiment (see FIG. 1). However, in the present embodiment, the target end detector 10A further includes a photodetector (light receiving means) 13 disposed in the processing chamber 31 as shown in FIG.

  The photodetector 13 is preferably arranged at a position where it can detect light transmitted through the target T3 and is not exposed to high-concentration plasma and does not interfere with film formation on the workpiece W. The photodetector 13 can be a known light receiving element, and includes a shutter (not shown) that can be opened and closed by a signal from the outside of the sputtering apparatus 30 so that film material does not adhere to the light receiving element. Alternatively, the photodetector 13 may include a moving means (not shown) and may be moved so as to face the surface of the target T3 at the time of inspection. The drive current for the light receiving element and the shutter of the photodetector 13 can be supplied from the outside of the processing chamber 31 by the method described in the first embodiment, similarly to the light source 12. When the light receiving element detects the light transmitted through the target T3, it transmits a signal to an external display means (not shown) to notify that the target T3 has reached the use limit.

  Such an inspection does not need to be continuously performed (monitored) as in the first embodiment, and the shutter is opened during the processing of the sputtering apparatus 30 so that the film material does not adhere to the light receiving element of the photodetector 13. Since it is closed and covers the light receiving element, it cannot be inspected. That is, as in the first embodiment, the inspection may be performed each time a film is formed on a predetermined number (one or more) of objects to be processed W. The light source 12 is turned on in accordance with the inspection, and the light receiving element of the photodetector 13 is detected. It is sufficient to supply a drive current to and open the shutter. This series of operations may be automatically performed according to a program or the like when the workpiece W is transported. Furthermore, when the light receiving element of the light detector 13 detects light and transmits a signal, it may be set so that processing of a new object to be processed W is not performed (carrying into the processing chamber 31 is stopped). Such a photodetector 13, a series of operations, and the like can also be applied to the target end detector 10 (see FIG. 1) mounted on the ion beam sputtering apparatus 20 in the first embodiment.

  As described above, the target end detector according to the second embodiment can be applied to the magnetron sputtering apparatus in which the target is thinned and consumed in a complicated shape to detect the use limit of the target. Similar to the target end detector according to the embodiment, it can be easily mounted on an existing sputtering apparatus, and the effects of cost reduction and productivity improvement can be obtained. Further, the end detection accuracy can be increased by devising the number and position of the light guides of the target end detector. In addition, the processing chamber is equipped with a photodetector that detects light transmitted through the target, so that light can be detected at a position closer to the target, and weaker light is detected to detect the use limit early. be able to.

  The embodiments for implementing the target end detector according to the present invention have been described above. However, the present invention is not limited to these embodiments, and various modifications can be made within the scope of the claims. It is.

10 Target end detector (sputter source end detection mechanism, light projecting means)
10A target end detector (sputter source end detection mechanism)
11 Light guide 12 Light source 13 Photodetector (light receiving means)
20 Ion beam sputtering equipment (sputtering equipment)
21 processing chamber 21a window 30 magnetron sputtering device (sputtering device)
31 Processing chamber 33 Magnet (magnetic field source)
25, 35 Target holder (sputter source holder, sputter source mounting member)
25c, 35c groove (concave)
26 Backing plate (Sputter source mounting member)
26c Groove (concave)
T1, T2, T3 target (sputter source)
W Workpiece

Claims (8)

Provided with a light projecting means for irradiating light on the back surface of the sputtering source installed in the processing chamber of the sputtering apparatus,
The light projecting means is housed in a recess formed on the surface of the sputtering source mounting member on which the sputtering source is mounted, and is disposed on the back side of the portion of the sputtering source consumed by the sputtering device ,
Sputter source end detection mechanism wherein the sputter source mounting member is characterized by either Der Rukoto backing plate of the sputtering source holder or the sputter source of the sputtering apparatus. Said light projecting means, according to claim 1 which portion is accommodated in the recess of the sputter source mounting member is formed into a rod or tube, characterized in that it is disposed along the back surface of the sputtering source Sputter source end detection mechanism. The said light projection means is provided with the light source and the light guide which irradiates light to the back surface of the said sputtering source connected to the said light source, The sputtering source termination | terminus detection of Claim 1 or Claim 2 characterized by the above-mentioned. mechanism. The light receiving means for detecting the light emitted from the light projecting means that passes through the sputtering source is further provided at a position that does not affect the processing of the object to be processed by the sputtering apparatus. sputter source end detection mechanism according to any one of 3. A sputtering apparatus comprising the sputtering source end detection mechanism according to any one of claims 1 to 3 ,
A sputtering apparatus, wherein a window through which a surface of a sputtering source installed in the processing chamber can be observed from outside the processing chamber is provided on a wall of the processing chamber. A sputtering apparatus comprising: the sputtering source terminal end detection mechanism according to any one of claims 1 to 3 ; and a light receiving unit disposed at a position that does not affect processing on the object to be processed,
The sputtering apparatus characterized in that the light receiving means detects light irradiated from a light projecting means of the sputtering source end detection mechanism that passes through a sputtering source installed in a processing chamber. An ion beam sputtering apparatus for irradiating the surface of the sputtering source with an ion beam,
It said light projecting means, a sputtering apparatus according to claim 5 or claim 6, characterized in that the ion beam irradiates the light to the back surface in the region of the sputter source for incident. A magnetron sputtering apparatus including a magnetic field generation source,
It said light projecting means, a sputtering apparatus according to claim 5 or claim 6, wherein the irradiating light to the back surface of the sputtering sources in the strong areas of magnetic field generated from the magnetic source.

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