JP2010116629A - Substrate-treating apparatus and method for monitoring occurrence of arcing in substrate-treating apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently prevent arcing which is abnormal electrical discharge that occurs when a member such as a shadow ring is placed so as to be brought into close contact with the rim of a substrate. <P>SOLUTION: In a process chamber 1, a tungsten film 92 is formed on a substrate 9 held by a substrate holder 3 with a sputtering method. The substrate 9 is electrostatically adsorbed by a dielectric plate 31 due to voltage applied to an adsorption electrode 32 from an adsorption electric source 33. A shadow shield 62 prevents the deposition of a thin film onto a region from the rim of the substrate 9 to a predetermined distance therefrom. An electroconductive film 71 covers a part of the surface of the dielectric plate 31, comes into contact with the back surface of the substrate 9, is insulated from the ground, and also is short-circuited with the shadow shield 62 through a wire 76 for a short circuit. An electric potential of the electroconductive film 71 is measured with a voltmeter 72, and a determining means 74 determines the occurrence of arcing from a sudden change of a measured value of the voltmeter 72. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The invention of the present application relates to a substrate processing apparatus (sputtering apparatus) for forming a thin film in a vacuum, and more particularly to the formation of a thin film for wiring formation in a highly integrated semiconductor process. The invention of the present application can also be applied to the production of thin films performed when manufacturing various other electronic components.

Thin film fabrication technology is greatly affected by the expansion of application fields and the high functionality and multi-functionality of products that are applied. In particular, in the manufacture of CMOS transistors used in DRAMs and various logics, it is an important issue to meet demands such as high-speed response.
For example, FEOL (Front
End Of Line) requires high-speed response, particularly high-speed response of the gate electrode. Due to this requirement, improvements have been made in the structure and material selection of the gate electrode, and a polycide-type gate electrode obtained by alloying a metal such as tungsten and polysilicon with a metal layered on the polysilicon layer. It has changed to a type of gate electrode. This is because the polycide such as WSi does not reduce the capacitance and consequently cannot respond at high speed. Also, polycide-type gate electrodes employ polycide (so-called salicide) alloyed by high-temperature processing, but salicide cannot reduce the resistance, so there is still a problem of lack of high-speed response. .

Created a thin film of refractory metal such as W (tungsten) with the metalization of the electrode structure against the backdrop of the demand for high-speed response as described above, high integration of products, high functionality, and multi-functionality. There is a lot to do. Along with this, new manufacturing process problems have emerged.
In the case of a refractory metal such as tungsten, the thin film is likely to be deposited with a large internal stress. Thin films are often created across the surface of the substrate. At this time, there is a case where deposition is performed so as to partially wrap around the back surface from the peripheral edge of the substrate. Thus, the film deposited on the periphery of the substrate or the film deposited around the back surface is likely to peel off when the substrate is handled in a later process and generate particles (a general term for fine particles that pollute the substrate). . This possibility is particularly high in the case of a film having a high internal stress such as a tungsten thin film. In the case of a thin film of the same type of material as the substrate such as a silicon film or silicon oxide film, it can be said that the possibility of fouling the substrate is low. However, in the case of a metal film such as tungsten, a fouling such as a short circuit is caused. The possibility is high.

  In order to solve such a problem, there is a case in which a thin film is not deposited on a certain region from the periphery of the substrate. Patent Document 1 discloses a configuration for that purpose, and a member called a shadow ring is arranged to form a film. The shadow ring is a ring-shaped member that is disposed close to the periphery of the substrate, and is a member that prevents a thin film from being deposited in a certain region from the periphery of the substrate by a so-called shadow effect. The shadow effect is mainly in sputtering, and is an effect of preventing deposition of a thin film as a result of shielding sputtered particles.

JP 2002-294441 A

The generation of particles described above can be solved by removing the thin film deposited on a certain area from the peripheral edge of the substrate prior to the post-process, but the removal work is cumbersome and difficult, reducing productivity and workability. . According to shadow ring, there is no such problem.
However, according to the inventor's research, it has been found that if there is a member arranged close to the periphery of the substrate, such as shadow ring, abnormal discharge called arcing occurs and the substrate is seriously damaged. .

FIG. 9 is a diagram schematically showing the surface of the substrate on which arcing has occurred. When arcing occurs, a complicatedly branched linear streak 90 that should be called a pine needle shape remains on the surface of the substrate 9. It is presumed that the streak 90 is caused by a result of a current flowing due to creeping discharge, that is, abnormal discharge along the surface of the substrate 9. In any case, when arcing occurs, the substrate is often unusable, and processes already performed are wasted, greatly reducing yield.
The invention of the present application has been made to solve such a problem, and has technical significance to provide a method and apparatus for realizing a substrate processing process that effectively prevents the occurrence of arcing.

In order to solve the above-described problems, a substrate processing apparatus according to the present invention is a substrate processing apparatus that performs a predetermined process using plasma on a substrate in a process chamber, and the substrate is placed at a predetermined position in the process chamber. A substrate holder to be held, a proximity member arranged close to the periphery of the substrate held by the substrate holder, an exhaust system for exhausting the inside of the process chamber, a plasma forming means for forming plasma in the plasma chamber, and a substrate A conductive film that is formed so as to cover a part of the surface of the substrate holder that is the mounting surface and is in contact with the substrate and is insulated from the ground, and a voltmeter that measures the potential of the conductive film; Judgment means for judging the occurrence of arcing, which is a defect caused by an abnormal current flowing along the surface of the substrate, from abrupt fluctuations in the measured value of the voltmeter. And wherein the are.
Alternatively, in order to solve the above-described problem, the arcing occurrence monitoring method in the substrate processing apparatus according to the present invention forms a plasma in the process chamber, and processes the substrate by the plasma while placing and holding the substrate on the substrate holder. A method for monitoring the occurrence of arcing in a substrate processing apparatus, which is formed so as to cover a proximity member disposed close to the periphery of a substrate held by a substrate holder and a part of a substrate mounting surface of the substrate holder. A conductive film in contact with the substrate, and the potential of the conductive film is measured, and the occurrence of arcing, which is a defect caused by an abnormal current flowing along the surface of the substrate, is caused by a rapid fluctuation of the measured potential. It is characterized by judging from.

  As described below, according to the present invention, since the occurrence of arcing is monitored, when arcing occurs, it is possible to take appropriate measures such as canceling the single wafer processing, etc. The increase in damage due to the occurrence of arcing can also be prevented in advance. In addition, the above effect can be obtained in a sputtering apparatus having a shadow shield that easily causes arcing. In addition to the above effects, there is no problem that arcing occurrence monitoring is highly reliable and electrostatic adsorption becomes unstable. In addition to the above effects, there is no problem that the electrostatic adsorption becomes unstable. In addition, since the occurrence of arcing is monitored in an apparatus for producing a tungsten thin film that is prone to arcing, it is possible to take appropriate measures such as stopping the single wafer processing when arcing occurs, and continue processing. For other substrates, it is possible to prevent an increase in damage due to arcing.

1 is a schematic front sectional view of a substrate processing apparatus according to a first embodiment of the present invention. 3 is a schematic cross-sectional view showing a positional relationship between a shadow shield 62 and a substrate 9. FIG. It is the cross-sectional schematic shown about the creation experiment of the tungsten thin film performed in order to pinpoint the generation | occurrence | production mechanism of arcing. It is the schematic which showed the electric potential change in the case of the process of the board | substrate 9 which arcing generate | occur | produced. It is the schematic shown about the generation | occurrence | production mechanism of arcing. It is the plane schematic which showed the pattern of the electrically conductive film 71 in the arcing monitor shown in FIG. It is the cross-sectional schematic explaining the thickness of the electrically conductive film 71. FIG. It is a front section schematic diagram of the substrate processing device concerning a second embodiment of the invention in this application. It is the figure which showed typically the surface of the board | substrate 9 which the arcing produced.

The best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described below. In the following description, a sputtering apparatus is taken as an example of a substrate processing apparatus.
FIG. 1 is a schematic front sectional view of a substrate processing apparatus according to a first embodiment of the present invention. The apparatus shown in FIG. 1 includes a process chamber 1 having an exhaust system 11, a cathode 2 provided in the process chamber 1, and a substrate holder for holding a substrate 9 to be deposited at a predetermined position in the process chamber 1. 3 is provided.
The process chamber 1 is an airtight vacuum vessel provided with a gate valve 10 for taking in and out the substrate 9. The exhaust system 11 includes a predetermined vacuum pump and is configured to exhaust the process chamber 1 to a vacuum pressure of about 5 × 10 −6 Pa.

The cathode 2 is attached to the upper wall portion of the vacuum chamber 1. The cathode 2 has a structure that realizes magnetron sputtering. The cathode 2 includes a target 21 provided with the surface exposed in the process chamber 1, a magnet unit 22 provided behind the target 21, and the like. The target 21 is made of a thin film material to be produced, and is made of, for example, tungsten. The magnet unit 22 includes a center magnet 221 and a peripheral magnet 222 that surrounds the center magnet 221.
A sputtering power source 23 for applying a voltage for sputtering discharge is connected to the target 21. As the sputtering power source 23, one that outputs a negative DC voltage or a high-frequency voltage is used. In addition, a rotation mechanism (not shown) is provided that rotates the entire magnet unit 22 relative to the target 21 to make the erosion uniform.

  The process chamber 1 is provided with a gas introduction system 4 for introducing a gas for sputtering discharge. Argon, nitrogen, or the like is used as a gas for sputtering discharge. The gas introduction system 4 includes a pipe 41 connected to the process chamber 1, a valve 42 provided on the pipe 41, a flow regulator (not shown), and the like. When the sputtering power source 23 operates while the gas introduction system 4 is introducing gas at a predetermined flow rate, sputter discharge occurs and the target 21 is sputtered. Particles (usually in an atomic state) are released from the target 21 by sputtering, and the particles (hereinafter, sputtered particles) reach the surface of the substrate 9 to deposit a thin film. In this specification, the term “surface of the substrate” may refer to the surface of the substrate 9 itself. However, when the film formation process has already been performed on the substrate 9, the thin film formed on the substrate 9 Sometimes refers to the surface.

  The substrate holder 3 is a stage-like member that places and holds the substrate 9 on the upper surface. The substrate holder 3 is provided with an electrostatic adsorption mechanism so as to hold the substrate 9 by electrostatic adsorption. Specifically, a plate-like portion (hereinafter referred to as a dielectric plate) 31 made of a dielectric is provided at the top of the substrate holder 3. A pair of suction electrodes 32 are provided in the dielectric plate 31, and a suction power source 33 for applying a suction voltage is connected to the suction electrodes 32. The dielectric plate 31 is dielectrically polarized by the voltage applied by the suction power source 33 and charges are induced on the surface, whereby the substrate 9 is electrostatically attracted. The substrate 9 is held at a position coaxial with the target 21.

  The substrate holder 3 is provided with a moving mechanism 5 for transferring the substrate 9 and adjusting the position of the substrate 9. An opening is provided in the bottom plate portion of the process chamber 1, and the column portion 34 of the substrate holder 3 is layered through this opening. The moving mechanism 5 is provided below the process chamber 1 (atmosphere side). The moving mechanism 5 holds the lower end of the column portion 34 of the substrate holder 3 and moves the substrate holder 3 by raising and lowering the column portion 34. A bellows 12 for preventing vacuum leakage from the opening is provided. The bellows 12 is fixed to the process chamber 1 so that the upper end surrounds the edge of the opening, and the lower end is fixed to a flange plate 37 attached to the column portion 34.

A heater 35 is provided in the substrate holder 3 for maintaining the temperature of the substrate 9 at the time of film formation at a predetermined high temperature. Further, a heat exchange gas introduction system 36 is provided that improves the heat exchange efficiency by introducing gas into a minute gap between the substrate 9 and the substrate holder 3 to increase the pressure. In some cases, a configuration in which the substrate 9 is maintained at a predetermined temperature while being cooled may be employed.
Even if the substrate holding surface of the substrate holder 3 is a flat surface, it cannot be made completely flat, but is microscopically rough, and a fine space is formed at the interface with the substrate 9. Since this space is a vacuum pressure during processing and heat exchange efficiency is poor, a concave portion (not shown in FIG. 1) having a certain shape is provided on the substrate holding surface. The heat exchange gas introduction system 36 is configured to introduce a heat exchange gas into the recess to increase the pressure.

Two shields 61 and 62 are provided in the process chamber 1. One is an adhesion shield 61 and the other is a shadow shield 62. The deposition shield 61 is for preventing unnecessary film deposition on the exposed surface in the process chamber 1. When a film is deposited on the exposed surface in the process chamber 1 (for example, the wall surface of the process chamber 1) and becomes thick, it peels off due to its own weight or internal stress and generates particles. Therefore, the deposition shield 61 is provided to prevent unnecessary deposition of the film on the exposed surface.
The deposition shield 61 has a cylindrical shape surrounding a space between the cathode 2 and the substrate holder 3. The surface of the deposition shield 61 is provided with irregularities that prevent the deposited thin film from peeling off. Further, the deposition shield 61 is provided so as to be replaceable, and is replaced after a predetermined number of film forming processes.

  The shadow shield 62 prevents the film from being deposited in a predetermined region (hereinafter referred to as a margin) along the peripheral edge of the substrate 9. Since the substrate 9 is circular, the shadow shield 62 is an annular member. The shadow shield 62 is provided at a position coaxial with the substrate 9 placed on the substrate holder 3. The shadow shield 62 has the same purpose as the shadow ring described above, but in other words, the shadow shield 62 is not limited to a ring shape in the present invention. The shadow shield 62 is supported by the shield column 621 and is fixed to the process chamber 1.

FIG. 2 is a schematic cross-sectional view showing the positional relationship between the shadow shield 62 and the substrate 9. In FIG. 2, the distance between the surface of the shadow shield 62 facing the substrate 9 (the lower surface) and the substrate 9 is indicated by d1. The distance between the inner edge of the shadow shield 62 and the peripheral edge of the substrate 9 in the direction parallel to the substrate 9 is indicated by d2.
d1 is important from the viewpoint of appropriately obtaining a shadow effect (film deposition preventing effect). When d1 becomes large, the shadow effect cannot be sufficiently obtained, and the film is easily deposited in the margin. If d1 is too small, the shadow shield 62 is likely to come into contact with the substrate 9, and the requirements for the placement position accuracy of the substrate 9, the dimensional accuracy of the shadow shield 62, the placement position accuracy, and the like become too high. Further, as a result of film deposition on the surface of the shadow shield 62, there is a problem that the shadow shield 62 and the substrate 9 are connected via the deposited film. In this case, when the substrate 9 is removed from the substrate holder 3, the film may break and generate particles. Therefore, d1 is preferably 0.2 mm or more and 2 mm or less.
Further, d2 is appropriately determined depending on how far the film is deposited from the periphery. For example, this distance is 1.5 to 3 mm, and when the substrate 9 is a semiconductor wafer having a diameter of 300 mm, the inner diameter of the shadow shield 62 is 296 to 294 mm.

Next, the configuration of the arcing monitor that constitutes a major feature of the apparatus of the present embodiment will be described.
Formation of the conductive film on the substrate holding surface of the substrate holder 3 is based on the inventors' research on arcing. The inventors of the present application conducted an experiment to find out the generation mechanism of arcing. The experiment was conducted while producing a tungsten thin film in which arcing frequently occurs. FIG. 3 is a schematic cross-sectional view showing an experiment for making a tungsten thin film performed to determine the mechanism of arcing.

Tungsten is formed on the base film 91 as shown in FIG. The base film 91 is a thin film made of a material having lower internal stress than tungsten and high adhesion to the substrate 9. As the base film 91, for example, a film made of TiN (titanium nitride) is employed. The base film 91 serves to connect the substrate 9 and the tungsten thin film 92. The base film 91 is formed by a chemical vapor deposition (CVD) method, but may be formed by a physical vapor deposition (sputtering or the like) method.
The base film 91 is formed in the entire region of the surface of the substrate 9 including the periphery without using a member such as the shadow shield 62 in a process chamber different from the process chamber 1. As shown in FIG. 3, the base film 91 may be deposited slightly around the back surface of the substrate 9. Since the underlying film 91 has low internal stress and high adhesion to the substrate 9, the problem of particle generation due to peeling is less than that of the tungsten thin film 92. Therefore, there is often no need to remove prior to the subsequent process.

In the experiment, a tungsten thin film 92 was formed after forming the base film 91 as described above on a silicon substrate 9 with a thickness of about 0.05 to 0.1 μm. At this time, as shown in FIG. 3, a shadow shield 62 was used to prevent the deposition of the tungsten thin film from the peripheral edge of the substrate 9 to a certain region. The film thickness of the tungsten thin film 92 was about 0.02 to 0.07 μm.
The inventors intended to measure the surface potential of the substrate 9 during the formation of the tungsten thin film in order to find out the mechanism of arcing. Since it is difficult to directly measure the surface potential, a conductive film 71 is formed on the substrate holding surface of the substrate holder 3, and the silicon substrate 9 is placed with the substrate 9 in contact with the conductive film 71. The potential of the conductive film 71 at that time was measured with a voltmeter 72.

  More specifically, the power applied to the cathode 2 by the sputtering power source 23 is 4000 W, the pressure in the process chamber 1 under the introduction of argon is maintained at about 1.0 Pa, and a voltage of ± 250 V is applied by the power source for adsorption. Then, a tungsten thin film 92 was formed by sputtering while electrostatically adsorbing the substrate 9. At this time, it was found that the potential of the conductive film 71 measured by the voltmeter 72 was about −30 V, and the back surface of the substrate 9 was at the same level.

  FIG. 4 is a schematic diagram showing potential changes during processing of the substrate 9 where arcing has occurred. The processing of the substrate 9 was repeated under the same conditions as described above, and the measurement by the voltmeter 72 was continuously continued during the processing, and the change in potential was monitored. When the change in the potential of the conductive film 71 during the processing of the substrate 9 in which arcing has occurred is seen from the state of the substrate 9 after the processing, as shown in FIG. 4, it rapidly changes from a potential of about −30V. It was found that the voltage was changed to 0 V (ground potential). It can be easily imagined that the time of this rapid change in potential is the time of occurrence of arcing.

From the above results, it is surmised that the arcing occurrence mechanism is as follows. FIG. 5 is a schematic view showing an arcing generation mechanism.
The surface of the substrate 9 held by the substrate holder 3 has substantially the same potential as the surface of the substrate holder 3 and charges are induced. The surface potential of the substrate 9 includes an insulating potential (floating potential) as well as a potential due to a voltage for electrostatic adsorption. That is, when the surface of the conductor insulated from the ground comes into contact with the plasma, the surface of the conductor has a negative potential of about several volts to several tens of volts due to the relative mobility of electrons compared to ions. The insulation potential is included in the potential of the substrate 9 when arcing occurs.
In the process of forming a film on the substrate 9 held with potential in this way, the sputtered particles reach not only the substrate 9 but also the surface of the shadow shield 62, so that the film 60 is also formed on the surface of the shadow shield 6. Is inevitable to deposit. Since the sputtered particles also enter the gap between the substrate 9 and the shadow shield 62, the film 60 is deposited little by little on the surface (lower surface) of the shadow shield 62 facing the substrate 9.

  The inventors believe that arcing is caused by film deposition on the surface of the shadow shield 62 facing the substrate. That is, as shown in FIG. 5A, as a result of film deposition on the substrate facing surface, the deposited film 60 and the substrate 9 come into contact with each other. Since the shadow shield 62 is grounded, when the deposited film 60 is a conductive film, the substrate 9 is also short-circuited to the ground due to the contact, and the charge induced on the surface of the substrate 9 is transferred to the deposited film 60 and the shadow. It suddenly flows to the ground through the shield 62. In the case of a process for forming an insulating film, a large amount of charge is also induced on the surface of the film deposited on the substrate 9. It is considered that the electric charge is transferred to the shadow shield 62 along the surface of the film deposited on the shadow shield 62, and a ground fault is generated in a state of a kind of creeping discharge. Such a phenomenon is presumed to be an arcing occurrence mechanism. The streak 90 shown in FIG. 9 is presumed to be an arcing mark caused by such a phenomenon.

  As shown in FIG. 5B, the film deposition on the substrate facing surface of the shadow shield 62 is not uniform, and the film 60 is likely to be deposited in a locally raised state. Since the raised portion of the film 60 first contacts the substrate 9, a current flows intensively through this portion. Further, since the electric field concentrates at the portion where the deposited film 60 is raised, electric discharge is generated even when the contact with the substrate 9 is not reached, and the charge induced on the surface of the substrate 9 rapidly flows to the ground through the shadow shield 62. Sometimes. It is speculated that arcing is caused by this phenomenon.

  In particular, when the tungsten thin film 92 is formed, the base film 91 is formed in advance up to the periphery of the substrate 9, and the film 60 deposited on the shadow shield 6 is likely to come into contact with the base film 91. Depending on the material of the underlying film 91, it may be possible to prevent arcing even if contacted, but the material is limited from the viewpoint of relaxing internal stress and improving adhesion to the substrate. Actually it is difficult. Similarly to the tungsten thin film 92, the base film 91 may not be formed in a certain region from the periphery of the substrate 9, but the effect of improving the adhesion of the tungsten thin film 92 to the substrate 9 is insufficient. There is a risk of becoming.

In any case, the inventors of the present application confirmed an abrupt change in potential in the processing when arcing as described above occurred. Based on such knowledge, the inventors have conceived a configuration of an arcing monitor that determines whether or not arcing has occurred by constantly monitoring potential changes.
As shown in FIG. 1, the arcing monitor has a conductive film 71 formed so as to cover a part of the surface of the dielectric plate 31 that is a substrate holding surface of the substrate holder 3, and a voltage with respect to the ground of the conductive film 71. It is mainly composed of a voltmeter 72 to be measured, a judgment means 73 for judging from a sudden change in a measured value of the voltmeter 72, a storage means 74 for storing the occurrence of arcing, and a display section 75 for displaying the occurrence of arcing. Has been.

In the present embodiment, the conductive film 71 is formed by laminating titanium and titanium nitride one by one. The film is formed by sputtering or vacuum deposition. The material of the conductive film 71 is not particularly limited as long as it is conductive, but a material (for example, heavy metal) that contaminates the substrate 9 should be avoided. Further, since the inside of the process chamber 1 is opened to the atmosphere during maintenance, a material that rapidly corrodes due to contact with the atmosphere should be avoided. Suitable materials for the conductive film 71 include Ta, TaN, Mo, Pt, Au, and the like.
If the conductive film 71 covers all of the dielectric plate 31, electrostatic adsorption of the substrate 9 becomes impossible, and thus a part thereof is covered. Specifically, the “part” should cover the area covered by the conductive film 71 up to 10% with respect to the entire back surface of the substrate 9. Beyond this, electrostatic adsorption is not impossible, but the adsorption becomes unstable.

  FIG. 6 is a schematic plan view showing the pattern of the conductive film 71 in the arcing monitor shown in FIG. The pattern of the conductive film 71 is not particularly limited, but is preferably a pattern that reaches each part so that arcing can be detected from any part on the back surface of the substrate 9. In particular, as shown in FIG. 9, since arcing is likely to occur along the periphery of the substrate 9, a radial pattern reaching the periphery of the substrate 9 is preferable, and at least three (equal intervals smaller than 120 degrees) are preferable. Or four or more radials (equal intervals smaller than 90 degrees). In addition, since an electrostatic adsorption force works in a region not covered with the conductive film 71, it is preferable to use a centrally symmetric pattern in order to achieve uniform electrostatic adsorption. The example shown in FIG. 6 is not completely centrally contrasted, but can achieve sufficiently uniform electrostatic attraction. The conductive film 71 can be formed in such a pattern by covering the film with a mask manufactured in accordance with the pattern to be formed and then forming the film.

  Careful consideration is also required for the thickness of the conductive film 71. FIG. 7 is a schematic cross-sectional view illustrating the thickness of the conductive film 71. In FIG. 7, the thickness of the conductive film 71 is indicated by t. When the conductive film 71 becomes thick, the electrostatic adsorption force becomes weak and the holding of the substrate 9 becomes unstable. Therefore, the thickness t is preferably 2 μm or less. Further, if the conductive film 71 becomes too thin, disconnection due to wear tends to occur, and there is a problem that the reliability of arcing monitoring is lowered. Therefore, the thickness t is preferably 0.5 μm (500 angstroms) or more.

It is also possible to define the thickness t in relation to the depth of the heat exchange recess formed on the substrate holding surface. FIG. 7 shows an example of this. FIG. 7 shows a recess 301 into which the heat exchange gas is introduced by the heat exchange gas introduction system 36 described above. As shown in FIG. 7, the substrate holding surface has a convex portion 302 that forms a concave portion 301 for heat exchange. The height h of the convex portion 302 (depth of the concave portion 301) is as small as about 0 to 20 μm, and is a distance at which the adsorption force due to the charge induced on the bottom surface of the concave portion 301 sufficiently acts on the substrate 9. . The height h (for example, 20 μm) has a margin (margin), and even if it is increased by about 10%, it is safe. Accordingly, it is preferable that the thickness t of the conductive film 71 is within 10% of the height h.
The conductive film 71 may be formed so as to cover only the surface of the convex portion 302, but may be formed so as to cover the inside of the concave portion 301. In that case, it is a matter of course that the protrusion 302 and the recess 301 are formed so as not to be interrupted at the stepped portion. As a specific example of the conductive film 71, in the case of the above-described laminated film of titanium and titanium nitride, there is an example in which the thickness is 1000 angstroms (total of 2000 angstroms).

  The determination means 73 is constantly inputted with the measurement value of the voltmeter 72 and compares a predetermined reference value with the measurement value. The apparatus includes a display unit 75 that displays the progress of processing and the occurrence of errors. When the measured value exceeds the reference value, the determining unit 73 determines that arcing has occurred, outputs an “arcing generation signal” to the display unit 75, and displays that fact on the display unit 75. Although the setting of the reference value becomes a problem, according to the study by the inventors, it is sufficient that arcing occurs when the change occurs by 10% or more from the normal potential. In the above example, since it is normally about -30V, -27V is the reference value. It should be noted that the occurrence of arcing is determined by the voltage fluctuation per unit time because the voltage fluctuation abruptly occurs, or may be judged by a value obtained by differentiating the voltage fluctuation with time.

The determination unit 73 can be easily configured by an electronic circuit using an operational amplifier IC or the like, and thus detailed description thereof is omitted. As the display unit 75, a display such as a CRT or a liquid crystal is adopted, but a simple one that lights an error lamp may be used. As the storage unit 74, a memory element such as a RAM is used. The apparatus includes a computer (not shown) as a controller for controlling each unit, and the determination unit 73, the storage unit 74, and the display unit may be provided as part of the configuration.
Note that wiring is provided in the substrate holder 3 to connect the conductive film 71 and the voltmeter 72. As shown in FIG. 7, a conductor portion 711 is provided so as to penetrate the dielectric plate 31, and the wiring is electrically connected to the conductive film 71 through the conductor portion 711.

Next, the operation of the apparatus of this embodiment will be described, which also serves as an explanation of the embodiment of the invention for monitoring the occurrence of arcing.
The process chamber 1 is evacuated by an exhaust system 11 to a predetermined vacuum pressure in advance. The substrates 9 are transferred to the process chamber 1 one by one by a transfer robot (not shown), and are placed and held on the substrate holder 3. From the time when the substrate 9 is held by the substrate holder 3, the operation of the arcing monitor is started. That is, measurement by the voltmeter 72 of the potential of the conductive film 71 on the substrate holder 3 is started.

The substrate holder 3 receives the substrate 9 at the lower limit position (standby position). Next, the moving mechanism 5 operates to raise the substrate holder 3 to a predetermined upper limit position (processing position). The upper limit position is a position where the distance between the substrate 9 and the shadow shield 62 becomes a predetermined value within the above-described range. In parallel, the suction power source 33 operates and the substrate 9 is electrostatically attracted.
After the substrate 9 is loaded, the gate valve 10 is closed, and the gas is introduced into the process chamber 1 by the gas introduction system 4. After confirming that the gas flow rate and pressure are maintained at predetermined values, the sputtering power source 23 operates to start sputtering discharge. Thereby, the target 21 is sputtered and a thin film is deposited on the surface of the substrate 9.

  After sputtering until the thin film deposited on the substrate 9 has a predetermined thickness, the operation of the sputtering power source 23 and the gas introduction system 4 is stopped. The moving mechanism 5 moves the substrate holder 3 to the lower limit position, and the suction power source 33 stops. After the exhaust system 11 exhausts the process chamber 1 again, the gate valve 10 is opened, and the transfer robot carries the substrate 9 out of the process chamber 1. The arcing monitor continues to operate until the substrate 9 is removed from the substrate holder 3.

  In the above operation, when the determination means 73 of the arcing monitor determines that arcing has occurred, the fact is stored in the storage means 74 together with the board ID. At the same time, the occurrence of arcing is displayed on the display unit 75. The sheet processing is stopped by the operator's operation or automatic control, and the cause of arcing is investigated. As described above, since arcing is considered to be caused by film deposition on the shadow shield 62, the film deposition on the shadow shield 62 is investigated, and if there is a local bulge or the like, the shadow shield 62 is replaced with a new one (or film). Replace with shadow shield 62 that has been removed. If it is determined that arcing has occurred, the processing of the substrate 9 may be terminated as usual, and then an investigation may be performed. However, when it occurs, the processing is immediately stopped and the substrate 9 is recovered and investigated. May be performed.

According to the above method and apparatus, since the arcing monitor constantly monitors the occurrence of arcing and determines the occurrence of arcing, it is possible to take appropriate measures such as stopping the single wafer processing when arcing occurs, and continue processing. By continuing, it is possible to prevent an increase in damage due to arcing of other substrates 9.
In the present embodiment, the shadow shield 62 is a grounded metal member, but this is not an essential requirement. For example, when the shadow shield 62 is biased to a positive potential for some reason, arcing is likely to occur. Also in this case, the configuration of the arcing monitor is extremely effective.

Next, the substrate processing apparatus of 2nd embodiment is demonstrated. FIG. 8 is a schematic front sectional view of a substrate processing apparatus according to the second embodiment of the present invention. The apparatus shown in FIG. 8 also has a process chamber 1 having an exhaust system 11, a cathode 2 provided in the process chamber 1, and a substrate holder for holding a substrate 9 to be deposited at a predetermined position in the process chamber 1. 3 is provided.
A major feature of the apparatus shown in FIG. 8 is that it has means for preventing the occurrence of arcing. This is also the result of the inventors' research.

  As described above, the inventors speculated that the grounding of the surface of the substrate 9 through the shadow shield 62 due to the film deposition on the shadow shield 62 may cause arcing. Therefore, the inventors can prevent arcing even if the shadow seal and the surface of the substrate 9 are connected by film deposition if the shadow shield 62 is insulated from the ground so as to have the same potential as the surface of the substrate 9. I thought that. Based on this idea, similarly, the conductive film 71 was provided on the substrate holding surface of the substrate holder 3, and the shadow shield 62 insulated from the ground was short-circuited to the conductive film 71 by wiring. Then arcing did not occur at all.

  Based on the above findings, the inventors have conceived a configuration of an arcing prevention means. That is, the arcing occurrence preventing means is formed so as to cover a part of the surface of the dielectric portion which is the substrate holding surface of the substrate holder 3 and is also insulated from the conductive film 71 insulated from the ground. The shadow shield 62 and the conductive film 71 are mainly composed of a short-circuit portion. As shown in FIG. 8, an insulating portion 622 is interposed between the shield column 621 and the shadow shield 62, and the shadow shield 62 is insulated from the ground.

  The configuration of the conductive film 71 and the configuration of the conduction circuit to it are the same as in the first embodiment. Similarly, a voltmeter 72 constituting an arcing monitor is provided. In the present embodiment, as shown in FIG. 8, the short-circuit portion is configured by a short-circuit wiring 76 that is branched from the wiring connected to the voltmeter 72 from the conductive film 71 and connected to the shadow shield 62. With this configuration, the occurrence of arcing is prevented. In addition to short-circuiting by the short-circuit wiring 76, a short-circuit may be caused by a metal structure (such as a rod-shaped member).

In the present embodiment, an insulation monitor is provided for monitoring whether the conductive film 71 (and the shadow shield 62) is insulated from the ground. The insulation monitor includes an insulation detection voltmeter 77 provided on a wiring 78 connecting the short-circuit wiring 76 and the ground.
Other members constituting the substrate holder 3 other than the dielectric plate 31 and the adsorption electrode 32, the process chamber 1 and the like are grounded for safety. If any of these members and the conductive film 71 or the shadow shield 62 are short-circuited for any reason, the conductive film 71 and the shadow shield 62 will be grounded. If a ground fault occurs, the electric charge flows to the ground, and electrostatic adsorption of the substrate 9 cannot be performed. Further, when the substrate holding surface of the substrate holder 3 is grounded, the spatial electric field between the substrate holder 3 and the cathode 2 is changed, which causes a problem that the reproducibility of the substrate processing is lowered.

  In the present embodiment, the insulation detection voltmeter 77 detects a ground fault of the conductive film 71 and the shadow shield 62 and generates an error signal. When an error signal occurs, the process is automatically stopped. For this reason, the substrate 9 is processed without being electrostatically attracted, and thus the temperature accuracy is not lowered or the reproducibility is lowered. Note that the insulation monitor may not be the voltmeter 77 but may simply detect that it has fallen to the ground.

In the apparatus of the present embodiment, the arcing monitor voltmeter 72 and the insulation detection voltmeter 77 are not necessarily required, and either or both of them may be omitted for cost reduction or the like.
Although the shadow shield 62 is described as being made of metal, it is sufficient that at least the surface facing the substrate 9 is made of metal. Therefore, a hollow shadow shield or a shadow shield having a structure in which the surface of the insulator is covered with metal may be used.
An embodiment of the invention of the method for producing a tungsten thin film corresponds to the experiment described above. As the base film 91, in addition to titanium nitride, a stacked film of titanium and titanium nitride or a stacked film of tantalum and tantalum nitride may be used as the base film 91.

  In each of the above-described embodiments, the sputtering apparatus is taken as an example of the substrate processing apparatus, but can be similarly applied to other substrate processing apparatuses. For example, a plasma CVD apparatus that forms a film by using a gas phase reaction in plasma, a dry etching apparatus that performs etching by using the action of active species or ions generated in plasma, and the like. In the case of a substrate processing apparatus using plasma and electrostatically adsorbing the substrate 9 on the substrate holder 3, arcing is likely to occur similarly. In particular, in the case of a thin film forming apparatus such as a plasma CVD apparatus, if there is a member such as a shadow shield 62 as in the case of a sputtering apparatus, a film is deposited there and easily causes arcing. Further, even in a dry etching apparatus, since the material volatilized from the surface of the substrate 9 is attached due to etching, if there is a member close to the surface of the substrate 9, it may be deposited there and cause arcing. Therefore, the invention of the present application can be applied to these apparatuses.

As for substrate processing apparatuses other than the thin film forming apparatus and the dry etching apparatus, arcing may occur in an apparatus of a type that uses plasma and processes the substrate 9 while electrostatically adsorbing, and the present invention is effective. is there. In the sputtering apparatus, the cathode 2 and the sputtering power source 23 that applies a voltage to the cathode 2 constitute plasma forming means.
Optimized for each device. For example, a high-frequency electrode provided in the process chamber 1 and a high-frequency power source that applies a high-frequency voltage to the high-frequency electrode may constitute plasma forming means.

In addition to the shadow shield 62, it is presumed that arcing is likely to occur in the configuration in which some members are arranged close to the periphery of the substrate 9, and the present invention is effectively applied to such a configuration. it can. In particular, it is more effective when there are protrusions where the electric field tends to concentrate or when the thin film tends to rise and deposit locally.
In each of the above embodiments, the shadow shield 62 has an annular shape. This is because the substrate 9 is circular, and in the case of a square substrate, a square ring-shaped shadow shield may be employed. In addition, a shadow shield other than the ring shape may be employed. For example, in the case where it is only necessary to prevent thin film deposition in a specific region of the region along the peripheral edge of the substrate, a shadow shield configuration that partially shields the region may be employed.

DESCRIPTION OF SYMBOLS 1 Process chamber 11 Exhaust system 2 Cathode 21 Target 3 Substrate holder 31 Dielectric plate 32 Adsorption electrode 33 Adsorption power source 35 Heater 36 Gas introduction system for heat exchange 4 Gas introduction system 5 Moving mechanism 62 Shadow shield 71 Conductive film 72 Voltmeter 73 Judgment Means 74 Storage means 75 Display section 76 Short-circuit wiring 77 Insulation detection voltmeter 9 Substrate 92 Tungsten thin film

Claims (9)

A substrate processing apparatus that performs predetermined processing using plasma on a substrate in a process chamber,
A substrate holder for holding the substrate in place in the process chamber;
A proximity member disposed close to the periphery of the substrate held by the substrate holder;
An exhaust system for exhausting the process chamber;
Plasma forming means for forming plasma in the plasma chamber;
A conductive film that is formed so as to cover a part of the surface of the substrate holder, which is a substrate mounting surface, is in contact with the substrate, and is insulated from the ground;
A voltmeter for measuring the potential of the conductive film;
A substrate processing apparatus comprising: a determination unit configured to determine the occurrence of arcing, which is a defect caused by an abnormal current flowing along the surface of the substrate, from a sudden change in a measured value of the voltmeter; . The predetermined process is to perform a thin film creation process by sputtering on the substrate in the process chamber,
The substrate processing apparatus according to claim 1, wherein the proximity member is a shadow shield that prevents deposition of a thin film on a region at a predetermined distance from a peripheral edge of the substrate. The substrate holder includes an electrostatic adsorption mechanism that electrostatically adsorbs the placed substrate,
The electrostatic adsorption mechanism includes a dielectric plate provided to form a substrate placement surface of the substrate holder, an adsorption electrode provided on the substrate holder to perform dielectric polarization on the dielectric plate, and an adsorption electrode With an adsorption power source that applies a voltage for electrostatic adsorption,
The substrate processing apparatus according to claim 1, wherein the conductive film is formed so as to cover a part of a surface of the dielectric plate which is a substrate mounting surface.   The thickness of the said electrically conductive film is 0.5 micrometer or more and 2 micrometers or less, The substrate processing apparatus of any one of Claims 1-3 characterized by the above-mentioned. The substrate holding surface of the substrate holder is provided with a recess,
The substrate processing apparatus according to claim 1, wherein the conductive film is formed on at least an upper surface of a convex portion that forms the concave portion.   The thin film forming process is characterized in that a tungsten thin film is formed by sputtering on the surface of a substrate on which a base film made of a material having lower internal stress and higher adhesion to the substrate than tungsten is formed. Item 6. The substrate processing apparatus according to any one of Items 1 to 5. An arcing occurrence monitoring method in a substrate processing apparatus for forming a plasma in a process chamber and processing the substrate by plasma while placing and holding the substrate on a substrate holder,
A proximity member disposed close to the periphery of the substrate held by the substrate holder;
A conductive film formed so as to cover a part of the substrate mounting surface of the substrate holder and in contact with the substrate;
A substrate processing apparatus, wherein the potential of the conductive film is measured, and the occurrence of arcing, which is a defect caused by an abnormal current flowing along the surface of the substrate, is determined from a sudden change in the measured potential. Monitoring method for arcing. The substrate holder includes an electrostatic adsorption mechanism that electrostatically adsorbs the placed substrate,
The electrostatic adsorption mechanism includes a dielectric plate provided to form a substrate placement surface of the substrate holder, an adsorption electrode provided on the substrate holder to perform dielectric polarization on the dielectric plate, and an adsorption electrode With an adsorption power source that applies a voltage for electrostatic adsorption,
8. The arcing occurrence monitoring method in a substrate processing apparatus according to claim 7, wherein the conductive film is formed so as to cover a part of the surface of the dielectric plate which is a substrate mounting surface.   9. The method for monitoring the occurrence of arcing in a substrate processing apparatus according to claim 7, wherein the proximity member is a shadow shield that prevents deposition of a thin film on a region at a predetermined distance from a peripheral edge of the substrate.