JP2002030433A - Thin film forming apparatus and method - Google Patents

Abstract

[PROBLEMS] To provide a thin film forming apparatus and a method capable of quickly and accurately detecting occurrence of a short circuit. SOLUTION: An electrometer 9 for measuring an electric potential of an inner mask 7 in contact with a glass substrate 2, a position sensor 6 for detecting a position of a magnetic circuit 5 moving on the back side of a target 1, and a magnetic circuit by the position sensor 6 The comparator which reads the output value of the electrometer 9 only when it is indicated that 5 is in a predetermined range and compares it with a predetermined threshold value corresponding to the occurrence of a short circuit, and outputs an error signal when the read potential is lower than the threshold value 10 is provided. Thereby, a short circuit can be detected in real time, and erroneous detection of a short circuit due to the position of the magnetic circuit 5 can be avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for forming a thin film for a large area substrate used for manufacturing a liquid crystal display or the like.

[0002]

2. Description of the Related Art In recent years, a technique for forming a thin film on a large-sized substrate has become important mainly in the field of displays such as liquid crystals. Among them, the sputtering method is widely used for forming a metal wiring film and an insulating film, and a method called a magnetron sputtering method is mainly used. The magnetron sputtering method is described in the Thin Film Handbook (Japan Society for the Promotion of Science
31 Committee) P. As indicated by reference numeral 187, a strong plasma discharge is generated on the target by disposing a magnetic circuit on the back side of the target, and the target material is formed on the opposite substrate.

In an array process in a liquid crystal device, the substrate used is an insulator made of glass, so that the surface of the substrate is charged up by electrons in the plasma and has a floating potential of several tens of volts. This phenomenon occurs because the substrate is in a floating state regardless of whether the film to be formed is metallic or non-metallic. At this time, if the film surface contacts even a small amount of the ground potential, the electric charge on the film formation surface becomes a current and concentrates on the contact portion, and an in-plane discharge that leaves a discharge mark occurs. In particular, when the film is a metal film, since all the film surfaces are at the same potential, all charges on the film surface are concentrated to cause an in-plane discharge, which causes great damage. For this reason, the mask member in contact with the substrate surface is normally insulated from the ground potential. However,
Since the floating of the mask member greatly affects the uniformity of the plasma discharge, only a part of the region near the substrate is floated.

FIG. 6 shows an example of a thin film forming apparatus, in which an inner mask 22 which is insulated from a ground potential (ie, floated) and which is arranged in a very small area around a substrate 21 is shown.
A magnetic circuit 2 is formed on the back side of a target 25 by using a mask 24 having a double structure in which an external mask 22 mechanically connected to a ground potential is connected via an insulating member (not shown).
6 is slid, and the plasma ring is moved on the target 25 so that a film is formed uniformly over the entire surface of the substrate 21 having a large area.

However, if the operation of the apparatus is performed for a long time,
Since the metal film adheres to many members in the discharge space,
A metal film adheres to an insulating member or the like between the inner mask and the outer mask, and short-circuiting between the two masks or short-circuiting due to a metal film piece or the like easily causes in-plane discharge. However, even if such a trouble occurs, the substrate 21 on which the film has been formed cannot be detected until the substrate 21 is directly visually observed, so that all the substrates 21 processed until the trouble is detected become defective. Therefore,
As shown, a voltmeter 27 is connected to the inner mask 22,
Short circuit is detected by detecting zero voltage.

[0006]

However, in the conventional thin film forming apparatus, the magnetic circuit 26 is repeatedly moved back and forth from one end of the target 25 to the other end for the purpose of uniform film formation as described above. The mask potential induced in the inner mask 22 tends to fluctuate greatly with the movement of the plasma ring.

More specifically, the magnetic circuit 26
5 When moving near the center, the highest density plasma ring exists in the center of the wide discharge space, so that the discharge impedance is low, and a large amount of charges are induced in the inner mask 22, and the potential of the inner mask 22 is reduced. Rises. On the other hand, when the magnetic circuit 26 approaches the turning point, the plasma ring also moves to the end of the target 25, so that the discharge impedance increases and the potential induced in the inner mask 22 decreases.

As described above, the inner mask 2 is moved by the movement of the plasma ring in the discharge space based on the movement of the magnetic circuit 26.
Conversely, a large change in the potential of No. 2 means that the potential value of the inner mask 22 and the range of the change greatly depend on the geometric dimensions of the discharge space and the sliding conditions of the magnetic circuit 26. When the magnetic circuit 26 is at the end of the target 25, the potential of the inner mask 22 may become zero.

Therefore, in the method of detecting a short circuit by detecting zero voltage as described above, a short circuit is erroneously detected only by moving the magnetic circuit to the end of the target. As a matter of course, when the detection threshold is increased, the probability of erroneous detection increases. Further, in this process, there is a factor that greatly affects the discharge stability such that the plasma ring moves, and an abnormal discharge such as an arc may occur on the way. When the arc discharge occurs, the discharge temporarily stops, so that the voltage induced in the inner mask becomes zero, and a short circuit is erroneously detected. Since the detection of the short circuit is not always accurate, it has been difficult to accurately and quickly detect the in-plane discharge.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide an apparatus and a method for forming a thin film capable of detecting the occurrence of a short circuit quickly and accurately.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention detects an electrometer for measuring the potential of a floating mask member in contact with a substrate and detects the position of a magnetic circuit moving on the back side of a target. Only when the position sensor indicates that the magnetic circuit is in a predetermined range of positions, the output value of the electrometer is read and compared with a predetermined threshold value corresponding to the occurrence of a short circuit, and the read potential is lower than the threshold value. By providing a comparator that sometimes outputs an error signal,
This makes it possible to quickly and accurately detect the occurrence of a short circuit.

The present invention also provides an electrometer for measuring the potential of a floating mask member in contact with a substrate, measuring means for measuring a discharge parameter corresponding to a position of a magnetic circuit moving on the back side of a target, and the position sensor. The comparator reads the output value of the electrometer only when it is indicated that the magnetic circuit is in a predetermined range, and compares it with a predetermined threshold value corresponding to the occurrence of a short circuit, and outputs an error signal when the read potential is lower than the threshold value. With the provision of a heater, the occurrence of a short circuit can be quickly and accurately detected.

[0013]

According to the first aspect of the present invention, a substrate to be processed and a target are arranged facing each other inside a vacuum chamber,
An inner mask member, which is insulated from a ground potential and is in contact with the substrate so as to surround a predetermined region of the substrate, is connected to an outer peripheral portion of the inner mask member via an insulating material on the target facing surface side of the substrate, and is connected to the ground. A mask comprising an outer mask member grounded to a potential is installed, and a magnetic circuit is movably installed near a back surface of the target which is opposite to the substrate, and the magnetic circuit is reciprocated from one side of the target to the other side. In a thin film forming apparatus that performs sputtering while performing, an electrometer for measuring the potential of the inner mask member,
A position sensor for detecting a position of the magnetic circuit; and a potential sensor provided connected to the electrometer and the position sensor, and the electrometer only when an output indicating a magnetic circuit position within a predetermined range is performed by the position sensor. And a comparator for outputting an error signal when the absolute value of the output voltage value is smaller than the reference voltage value, and comparing the absolute value of the read output voltage value with a predetermined reference voltage value. It is characterized by the following.

According to the above-described apparatus configuration, when the substrate to be processed is an insulating substrate such as a glass substrate, a charge similar to that of the substrate is generated on the inner mask member insulated from the ground potential, thereby generating a potential. Therefore, a reference voltage value as a detection threshold value in consideration of zero potential when the inner mask member is short-circuited to the ground, and a magnetic circuit excluding a position where the potential of the inner mask member becomes low regardless of the presence or absence of the short circuit If the range of the position is determined in advance, the short circuit can be detected in real time by monitoring the potential of the inner mask member with an electrometer and comparing the potential with the reference voltage value as described above. By using the position sensor to confirm the position of the magnetic circuit and employing the potential of the inner mask member, erroneous detection of a short circuit due to the position of the magnetic circuit can be avoided, and the occurrence of the short circuit can be detected quickly and accurately.

According to a second aspect of the present invention, in the thin film forming apparatus according to the first aspect, the magnetic circuit position within a predetermined range is a position excluding a turning point of the magnetic circuit and its vicinity. Therefore, erroneous detection of a short circuit near the turning point where the potential of the inner mask member can be zero can be reliably avoided.

According to a third aspect of the present invention, a substrate to be processed and a target are disposed inside a vacuum chamber so as to face each other, and a predetermined area of the substrate is insulated from ground on a side of the substrate facing the target and is insulated from ground. A mask comprising an inner mask member which is installed in contact with the substrate and an outer mask member which is connected to an outer peripheral edge of the inner mask member via an insulating material and is grounded to the ground potential, and a target which is contrary to the substrate A magnetic circuit is movably installed in the vicinity of the back of the target, and in a thin film forming apparatus that performs sputtering while reciprocating the magnetic circuit from one side of the target to the other side, an electrometer for measuring the potential of the inner mask member; Measuring means for measuring a predetermined discharge parameter with respect to a power supply for applying a voltage to the target, and provided in connection with the electrometer and the measuring means. The output value of the electrometer is read only when the output value from the measuring means is within a predetermined range, and the absolute value of the read output voltage value is compared with a predetermined reference voltage value. And a comparator for outputting an error signal when the absolute value is smaller than the reference voltage value.

According to the above-described apparatus configuration, the same fluctuation as the fluctuation of the inner mask potential accompanying the movement of the magnetic circuit appears in the discharge parameters of the power supply for applying a voltage to the target, such as the target voltage and the target current. Therefore, a reference voltage value as a detection threshold value in consideration of zero potential when the inner mask member is short-circuited to the ground, and a magnetic circuit excluding a position where the potential of the inner mask member becomes low regardless of the presence or absence of the short circuit If the variation range of the predetermined discharge parameter value corresponding to the position range is determined in advance, the short circuit is monitored in real time by monitoring the potential of the inner mask member with an electrometer and comparing with the reference voltage value as described above. Erroneous detection of a short circuit caused by the position of the magnetic circuit can be avoided by using the potential of the inner mask member while confirming the position of the magnetic circuit with the output value variation width of the discharge parameter. And the occurrence of a short circuit can be quickly and accurately detected. A range for reading the output value of the electrometer may be set for a calculated value obtained by multiplying the output value from the measuring means by a predetermined constant.

According to a fourth aspect of the present invention, in the thin film forming apparatus according to the third aspect, the discharge parameter is a target current. In the invention according to claim 5, a substrate to be processed and a target are disposed inside a vacuum chamber so as to face each other, and a target facing surface side of the substrate is
An inner mask member insulated from the ground potential and in contact with the substrate so as to surround a predetermined region of the substrate, and an outer mask member coupled to the outer peripheral edge of the inner mask member via an insulating material and grounded to the ground potential; Is installed, a magnetic circuit is movably installed in the vicinity of the back surface of the target which is opposite to the substrate, and sputtering is performed while reciprocating the magnetic circuit from one side of the target to the other side. In forming a thin film on the target-facing surface, the potential of the inner mask member is measured, and the position of the magnetic circuit is detected by a position sensor or by monitoring a predetermined discharge parameter. When the output value of the electrometer is within a predetermined range, the absolute value of the read output voltage value is determined by a predetermined reference. Compared with pressure value, characterized by stopping the formation of the thin film when the absolute value of the output voltage value is smaller than the reference voltage value.

According to the above configuration, when the absolute value of the output voltage value is smaller than the reference voltage value, it is determined that a short circuit has occurred, and the formation of the thin film is stopped. Therefore, the occurrence of defective substrates is minimized. Can be.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. (Embodiment 1) FIG. 1 shows a schematic configuration of a thin film forming apparatus according to Embodiment 1 of the present invention.

In a vacuum chamber (not shown), a target 1 and a large-sized glass substrate 2 are arranged to face each other, and a mask 3 is arranged on the glass substrate 2 on the side of the glass substrate 2 facing the target. A DC power supply 4 outside the tank is connected to the target 1.

A magnetic circuit unit 5 is provided on the back side of the target 1 opposite to the glass substrate 2 by being connected to a driving motor (not shown) via a ball screw, and is arranged in the short side direction of the unit (arrow). Direction), the target 1 is slidable from one side to the other side. The magnetic circuit unit 5 has a rectangular frame-shaped central magnet 5b and a peripheral magnet 5c arranged on a rectangular yoke 5a. The magnet surface is installed in a direction in which the magnet surface side is close to the target 1. Leakage magnetic flux between 5a and 5b is generated immediately above target 1. A position sensor 6 for detecting a position of the magnetic circuit 5 is provided on a back surface side of a magnetic circuit unit 5 (hereinafter, referred to as a magnetic circuit 5) which is opposite to the target 1.

The mask 3 has an inner mask 7 insulated from the ground potential and arranged in contact with the substrate surface so as to surround a predetermined area of the substrate 2, and an insulating member (not shown) is provided on the outer peripheral edge of the inner mask 7. And an outer mask 8 connected to the ground potential and connected to the ground potential. An electrometer 9 is connected to the inner mask 7, which is a floating mask insulated from the ground potential, via a conductive wire.

The position sensor 6 and the electrometer 9 are connected to a comparator 10 which processes each output value as described later. The operation of the above configuration will be described.

A sputtering gas is introduced into the vacuum chamber and adjusted to a predetermined pressure reducing condition. In this state, a high voltage is applied to the target 1 from the DC power source 4 to discharge the target 1 and generate plasma. By reciprocating from one end to the other end on the back side of the target 1 and moving the plasma ring on the target 1, a sputter film is formed uniformly over the entire surface of the glass substrate 2.

At this time, the position of the magnetic circuit 5 is detected by the position sensor 6, the potential generated in the inner mask 7 is detected by the electrometer 9, and each data signal is output to the comparator 10. .

On the other hand, the comparator 10 includes the position sensor 6
The position signal output from the electrometer 9 is continuously read, and the output value from the electrometer 9 is read only when the magnetic circuit 5 is at a position within a predetermined range excluding the vicinity of the turning point at the end of the target 1. The absolute value of the read output voltage value is compared with a predetermined reference voltage value, and an error signal is output when the absolute value of the output voltage value is smaller than the reference voltage value.
Here, the reference voltage value is set to a reference value (> 0, usually several volts) close to zero potential when a short circuit occurs between the inner mask 7 and the ground.

In this manner, the potential generated in the inner mask 7 insulated from the ground potential is monitored and compared with a reference voltage value to detect a short circuit in real time. Is confirmed by the position sensor 6 and the potential of the inner mask 7 is adopted, whereby erroneous detection of a short circuit near the turning point of the magnetic circuit 5 can be avoided, and the occurrence of the short circuit can be detected quickly and accurately.
Therefore, by promptly responding to the error signal, the occurrence of defective substrates can be reduced without unnecessarily interrupting the processing.

Hereinafter, a specific example will be described in detail. Using argon (Ar) gas as a sputtering gas, 37
A glass substrate having a size of 0 × 470 (mm ² ) and aluminum (Al) having a purity of 5N as a target were set at a distance of 70 mm therebetween.

The magnetic circuit has a distance (T / M distance) from the surface of the magnet to the surface of the target facing the substrate of 60 mm, and a magnetic field horizontal component on the target of about 200 to 300 Gauss.
s. The slide conditions of the magnetic circuit are as follows: slide width: ±
300mm, slide maximum speed: 120mm / sec,
45 mm from the turning point was set as the acceleration and deceleration distance of the magnet.

The discharge conditions were as follows: argon flow rate: 200 scc
m, vacuum chamber pressure: 0.4 Pa, applied power: 7.5 kW
And The target voltage at this time is about 440 to 470
V, the discharge current was about 16-17A.

FIG. 2 shows the relationship between the position of the magnetic circuit and the internal mask potential. As can be seen from FIG. 2, when the magnetic circuit approaches the turning point (± 300 mm) at the end of the target, the inner mask potential tends to decrease (it is a negative potential because electrons are charged up). That is, in the region where the magnetic circuit position is -250 mm to +250 mm from the target center position, the inner mask potential is -28 (V), but the magnetic circuit position is -300 to -250 mm and 250 to 300 mm.
In the target end region, the inner mask potential was small, and the potential was zero at the turning point.

Therefore, for example, if the magnetic circuit position is -25
It is assumed that the inner mask potential is read when it is within the range of 0 mm to +250 mm, and the reference voltage at the comparator is -5 (V). This means that when the absolute value of the inner mask potential (V) becomes smaller than 5, an error signal is output as a short circuit.

FIG. 3 shows the relationship between the position of the magnetic circuit and the output of the error signal. FIG. 3A shows a state in which the inner mask and the outer mask are insulated. Since the absolute value of the inner mask potential is 28 in the magnetic circuit position where the inner mask potential is read from -250 mm to +250 mm, an error occurs. No signal is output. FIG. 3B shows a state in which the inner mask and the outer mask are short-circuited, and the magnetic circuit position is from −250 mm to +250 mm.
Error signal is output in the range of -300 to -250 m
No error signal is output for m and 250-300 mm. In other words, if the position of the magnetic circuit approaches the turning point at the end of the target (-300 to -250 mm and 250
Even if the absolute value of the inner mask potential (−V) becomes smaller than 5, no error signal is output. (Embodiment 2) FIG. 4 shows a schematic configuration of a thin film forming apparatus according to Embodiment 2 of the present invention.

In the apparatus for forming a thin film according to the second embodiment, unlike the apparatus according to the first embodiment, a position sensor for detecting the position of a magnetic circuit is not provided. A measuring instrument 11 for measuring a predetermined discharge parameter such as
This is the point output from the measuring device 11 to the comparator 10.

The comparator 7 continuously monitors the predetermined discharge parameter (or at predetermined intervals), multiplies the obtained measured value by a predetermined constant, and calculates the calculated value by a predetermined detection reference value. The output value from the electrometer 9 is read only when it falls below (or above). And
The absolute value of the read voltage value is compared with a predetermined reference voltage value, and an error signal is output when the absolute value of the voltage value is smaller than the reference voltage value. Here, the reference voltage value is set to a reference value (> 0, usually several volts) close to zero potential when a short circuit occurs between the inner mask 7 and the ground. The detection reference value is set as an upper limit value or a lower limit value of a discharge parameter corresponding to a magnetic circuit position excluding a position where the potential of the inner mask 7 becomes low regardless of the presence or absence of a short circuit.

Thus, as in the first embodiment,
The potential generated in the inner mask 7 insulated from the ground potential is monitored and compared with a reference voltage value to detect a short circuit in real time. At this time, the position of the magnetic circuit 5 is determined via the output value of the discharge parameter. By adopting the potential of the inner mask 7 after confirmation, it is possible to avoid erroneous detection of a short circuit near the turning point of the magnetic circuit 5,
The occurrence of a short circuit can be detected quickly and accurately. Therefore, by promptly responding to the error signal, the occurrence of defective substrates can be reduced without unnecessarily interrupting the processing.

Hereinafter, a specific example will be described in detail. The implementation conditions were all the same as in Example 1 described above. FIG.
(a), (b), and (c) show the relationship between the magnetic circuit position and the target voltage, the target current, and the inner mask potential, which are the discharge parameters, respectively. 5 (a), 5 (b) and 5 (c), the target voltage, the target current, and the inner mask potential fluctuate according to the position of the magnetic circuit.

As shown in FIGS. 5 (a) and 5 (b), the positions of the magnetic field circuit are -300 to -250 mm and 250 to 3 near the turning point.
When the target voltage is in the target end region of 00 mm, the discharge impedance is high, so that the target voltage is -470.
(V), and accordingly the target current becomes 16
(A) and became smaller. This is presumably because the electrode area contributing to the discharge is apparently small in the target end region.

When the position of the magnetic circuit was at the center of the target, the discharge impedance was low and the discharge was easy, so that the target voltage dropped to -440 (V) and the target current increased to 17 (A). This is considered to be because the magnetic circuit position is shifted to the center of the target so that the discharge space can be widely used.

As can be seen from FIGS. 5B and 5C, the inner mask potential has a strong correlation with the target current. This is because the discharge density of the plasma is increased by increasing the target current. As a result, the amount of charges induced on the inner mask increases, and the inner mask potential increases.

Therefore, for example, as in the specific example of the first embodiment, the reference voltage at the comparator is set to -5 (V), and the target current 17 V corresponding to the magnetic circuit position of -250 mm to +250 mm is set as the reference value, and 17 V is applied. When the voltage falls below the threshold, the internal mask potential is read.

FIG. 5D shows a state in which the inner mask and the outer mask are insulated. Since the absolute value of the inner mask potential is 28 when the inner mask potential is in the range of 17 V or more at which the target current is read, an error occurs. No signal is output.

FIG. 5E shows a state in which the inner mask and the outer mask are short-circuited, and the magnetic circuit position is from -250 mm to +250 m.
An error signal is output when the target current is 17 V corresponding to m, -300 to -250 mm and 250 to 300 m
No error signal is output for target currents below 17V corresponding to m. That is, when the position of the magnetic circuit approaches the turning point of the target end (−300 to −250).
mm and 250-300 mm), the target current 17
Since V or less is detected, no error signal is output even if the absolute value of the inner mask potential (−V) becomes smaller than 5.

Although the target current is monitored here, a similar result can be obtained by monitoring the target voltage, power, etc. instead. When the measured value obtained by monitoring is small, it may be multiplied by a predetermined constant.

In each of the above embodiments, one or two magnetic circuits may be provided regardless of the number of magnetic circuits. It goes without saying that the same effect can be obtained even if the slide conditions, such as the slide width, speed, and acceleration / deceleration width of the magnetic circuit, are changed, and the deposition conditions relating to the discharge are changed. There is no particular limitation on the substrate size.

[0047]

As described above, according to the thin film forming apparatus of the present invention, by monitoring the potential generated in the inner mask insulated from the ground potential and comparing it with the reference voltage value, the occurrence of a short circuit can be realized in real time. In addition to being able to detect and monitor the position of the magnetic circuit, or the variation of the corresponding discharge parameter, or both at the same time, the potential of the inner mask is determined by simultaneously confirming the potential of the inner mask and monitoring the fluctuation. An erroneous short circuit can be avoided, and the occurrence of a short circuit can be detected quickly and accurately. Therefore, by taking quick action, the number of defective substrates can be reduced, and productivity can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a thin film forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a graph showing a relationship between a magnetic circuit position and an internal mask potential in the thin film forming apparatus of FIG.

FIG. 3 is a graph showing a relationship between a magnetic circuit position and an error signal output in the thin film forming apparatus of FIG.

FIG. 4 is a configuration diagram of a thin film forming apparatus according to a second embodiment of the present invention.

5 is a graph showing a relationship between a magnetic circuit position and each of a target voltage, a target current, an internal mask potential, and an error signal output in the thin film forming apparatus of FIG.

FIG. 6 is a configuration diagram of a conventional thin film forming apparatus.

[Description of Signs] 1 Target 2 Glass substrate 3 Mask 4 DC power supply 5 Magnetic circuit 6 Position sensor 7 Inner mask (floating mask) 8 Outer mask 9 Electrometer 10 Comparator 11 Measuring instrument

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Munewa Nishihara 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Kuniya Kanaya 1006 Okadoma Kadoma Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (72) Inventor Ryoichi Konishi 1006 Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. BD00 CA05 DC03 DC46 EA09 HA03

Claims (5)

[Claims] 1. A substrate to be processed and a target are disposed inside a vacuum chamber so as to face each other, and a substrate is provided on the side of the substrate facing the target so as to be insulated from ground potential and to surround a predetermined region of the substrate. A mask consisting of an inner mask member and an outer mask member that is connected to the outer peripheral edge of the inner mask member via an insulating material and is grounded to a ground potential,
In a thin film forming apparatus for arranging a magnetic circuit movably in the vicinity of a back surface of a target opposite to the substrate and performing sputtering while reciprocating the magnetic circuit from one side to the other side of the target, the potential of the inner mask member An electrometer for measuring the position of the magnetic circuit, and a position sensor connected to the electrometer and the position sensor, and an output indicating a magnetic circuit position within a predetermined range from the position sensor. Reading the output value of the electrometer only when performed,
A thin film, comprising: a comparator for comparing an absolute value of the read output voltage value with a predetermined reference voltage value and outputting an error signal when the absolute value of the output voltage value is smaller than the reference voltage value. Forming equipment. 2. The thin film forming apparatus according to claim 1, wherein the magnetic circuit position within the predetermined range is a position excluding a turning point of the magnetic circuit and its vicinity. 3. A substrate to be processed and a target are disposed inside the vacuum chamber so as to face each other, and are provided on the side of the substrate facing the target so as to be insulated from ground potential and to surround a predetermined area of the substrate. A mask consisting of an inner mask member and an outer mask member that is connected to the outer peripheral edge of the inner mask member via an insulating material and is grounded to a ground potential,
In a thin film forming apparatus for arranging a magnetic circuit movably in the vicinity of a back surface of a target opposite to the substrate and performing sputtering while reciprocating the magnetic circuit from one side to the other side of the target, the potential of the inner mask member And a measuring means for measuring a predetermined discharge parameter with respect to a power supply for applying a voltage to the target, provided in connection with the electrometer and the measuring means, and an output value from the measuring means is provided. The output value of the electrometer is read only when it is within a predetermined range, and the absolute value of the read output voltage value is compared with a predetermined reference voltage value, and the absolute value of the output voltage value is smaller than the reference voltage value. A thin-film forming apparatus comprising a comparator for outputting an error signal at times. 4. The thin film forming apparatus according to claim 3, wherein the discharge parameter is a target current. 5. A substrate to be treated and a target are disposed inside a vacuum chamber so as to face each other, and are provided on the side of the substrate facing the target so as to be insulated from ground potential and to surround a predetermined region of the substrate. A mask consisting of an inner mask member and an outer mask member that is connected to the outer peripheral edge of the inner mask member via an insulating material and is grounded to a ground potential,
A magnetic circuit is movably installed near the back of the target opposite to the substrate, and sputtering is performed while reciprocating the magnetic circuit from one side of the target to the other side to form a thin film on the target facing surface of the substrate. At this time, the potential of the inner mask member is measured, and the position of the magnetic circuit is detected by a position sensor or by monitoring a predetermined discharge parameter, and when the position of the magnetic circuit is within a predetermined range. Reading the output value of the electrometer, comparing the absolute value of the read output voltage value with a predetermined reference voltage value, and stopping the thin film formation when the absolute value of the output voltage value is smaller than the reference voltage value. A thin film forming method.