KR101231669B1 - Sputtering apparutus and sputtering method - Google Patents

Abstract

When a non-erosion area | region does not remain on a target and reactive sputtering is performed, the sputtering apparatus which can form a film of uniform film quality is provided.

The sputtering apparatus 2 of the present invention has three or more targets 241 arranged in parallel at predetermined intervals in the vacuum chamber 21, and a negative potential and an electrostatic potential with respect to each target 241. AC power supplies E1 to E3 alternately applying positive or ground potentials, and branch at least one of the outputs from AC power supplies E1 to E3 to connect to two or more targets 241, and this branch. Between the targets 241 connected to one output, switches SW1 to SW3 as switching means for switching a target to which a potential is applied from an AC power source are provided.

Sputtering, Vacuum Chamber, Target, AC Power, Switch

Description

Sputtering device and sputtering method {SPUTTERING APPARUTUS AND SPUTTERING METHOD}

1 is a schematic diagram of a conventional apparatus,

2 is a schematic configuration diagram of a sputtering apparatus of the present invention;

3 is a schematic configuration diagram of a vacuum chamber in the sputtering apparatus of the present invention;

(A), (b) is a schematic diagram of the film formation process in the sputtering apparatus of this invention,

5 is a timing chart when the magnet assembly is moved in parallel;

(A), (b) is a schematic diagram which shows another embodiment of the sputtering apparatus of this invention,

7 is a graph showing the number of occurrences of abnormal discharge with respect to integrated power;

FIG. 8A is a graph showing the relationship between the flow rate of O ₂ gas and the specific resistance when a film is formed using a conventional apparatus, and FIG. ₂ is a graph showing the relationship between the flow rate of a gas and a specific resistance.

<Code description>

241a to 241f: target 242a to 242f: electrode

25: magnet assembly 270: drive shaft

271: Ball screw E1 to E3: AC power

SW1 ~ SW3: Switching means S: Board

The present invention relates to a sputtering apparatus and a sputtering method.

When forming a thin film on a board | substrate, the magnetron sputtering system is used well by the advantage that a film formation speed is fast. In the magnetron sputtering method, a magnet assembly composed of a plurality of magnets with alternating polarities is alternately placed at the rear of the target, and the magnetic assembly forms a magnetic flux in front of the target to capture electrons, thereby reducing the electron density in front of the target. It raises, the probability of collision of these electrons and the gas introduce | transduced in a vacuum chamber is raised, and a plasma density is made high and sputtering is carried out.

By the way, as a board | substrate becomes large in recent years, the magnetron sputtering apparatus is also enlarged. As such, the sputtering apparatus which can form a film | membrane with respect to the board | substrate of a large area by installing several target in parallel is known (for example, patent document 1).

In this sputtering apparatus, since the component parts, such as an anode and a shield, for capturing the secondary electrons etc. which protruded from a target, are provided between targets, each target cannot be installed in close proximity, and the space | interval between targets becomes large. Since sputtering particles are not emitted from each other among these targets, the film formation rate is extremely slow in the opposing portions of the substrate surface, and the in-plane uniformity of the film thickness is deteriorated.

In order to solve such a problem, a sputtering apparatus as shown in FIG. 1 can be considered. The sputtering apparatus 1 connects the several target 12a-12d parallelly spaced in the vacuum chamber 11, and two targets 12a, 12b, 12c, and 12d which adjoin each other. It has a power source (E). Since the sputtering apparatus 1 is sputtered alternately by using one of the targets to which one AC power supply is connected as a cathode and the other as an anode, there is no need to provide a component such as an anode between the targets. Can be placed in close proximity.

(Patent Document 1) Japanese Unexamined Patent Publication No. 2002-508447 (for example, the description of claims)

However, when the targets are placed in parallel with each other in parallel, electrons emitted from the target are introduced into the anode in the upper space 121 of the adjacent target end portion, so that plasma P does not occur. Wealth is not sputtered and remains in a non-erosive area. In this case, even if the magnetic flux is moved parallel to the front of the non-erosion region, the target end portion cannot be eroded and cannot be eroded over the entire target surface, resulting in poor target utilization efficiency. Moreover, since a non-erosion area | region remains, it may become a cause of abnormal discharge and particle | grains during sputtering.

In addition, since plasma P is generated between adjacent targets to which one AC power source is connected, a space 122 having a lower plasma density than a space having a different plasma density is generated. In this case, when reactive gas is introduced into the sputtering apparatus 1 to carry out reactive sputtering, the reaction is not promoted at a portion where the plasma density is low, and the film quality in the surface of the substrate S is not uniform.

Here, the problem of the present invention solves the problems of the prior art, and provides a sputtering apparatus capable of forming a uniform film quality when reactive sputtering is left without a non-eroded region remaining on the target. I would like to.

According to claim 1, the sputtering apparatus of the present invention comprises three or more targets arranged in parallel in a vacuum chamber at predetermined intervals, and a negative potential, a static potential or a ground potential with respect to each target. An alternating current power source is provided alternately, at least one of the outputs from the alternating current power source is connected to two or more targets, and a target to which a potential is applied from the alternating current power source is switched between the targets connected to the branched outputs. Characterized in that the switching means to provide.

First, among the targets installed in parallel, one of two adjacent targets connected to one AC power source is used as a cathode and the other as an anode, and plasma is generated and sputtered alternately on these targets. Since no plasma is generated above, this portion is not sputtered and remains as a non-eroded area.

Next, the switching means converts one of the two targets connected to one AC power source into another target connected to the branched output, for example, a target not adjacent to the other target. The distance between the cathodes is widened, and electrons do not flow into the anode. As a result, plasma is generated in the upper portion of the non-eroded region, and the non-eroded region remaining on the target can also be sputtered, so that the entire surface of the target can be eroded.

In addition, since the target to which the potential is applied from the AC power source is switched by the switching means and the plasma generation position is changed, the space having a low plasma density also moves, so that the plasma density becomes substantially uniform in front of the substrate in the entire film formation time. When reactive sputtering is performed, a film of uniform film quality can be formed.

If the sputtering apparatus is provided with a magnet assembly composed of a plurality of magnets disposed behind each target to form a magnetic flux in front of each target, and drive means for driving the magnetic assemblies so that the magnetic flux moves in parallel with the target, By moving the magnet assembly in parallel to the left and right, the entire target surface can be eroded substantially uniformly.

It is also conceivable that if the magnet assemblies are placed behind each target, the magnets interfere with each other and the magnetic field balance is disturbed. In such a case, it is preferable to include magnetic flux density correction means for making the density of the magnetic flux formed by each magnet assembly substantially uniform.

According to claim 4, the substrate is sequentially transported to a position opposite to three or more targets arranged in parallel at a predetermined interval in the vacuum chamber, and alternately apply negative potentials and electrostatic potentials or ground potentials from the AC power supply to these targets. At this time, between two or more targets which branched and connected at least one of the outputs from an AC power supply, the target which applies a potential from an AC power supply is switched, and a plasma is generated on a target, and a film | membrane is formed on a board | substrate. It is done.

It is preferable to perform switching of a target by this switching means at a fixed period after the start of film formation. If it is performed in a fixed period, the time for connecting to each target, that is, the generation time of each plasma becomes uniform, and sputtering and erosion can be performed even if the non-eroded region remains on the target.

In the case where two targets are connected by dividing the output of the AC power supply, if the switching by the switching means is performed an odd number of times, the number of connections to each target becomes the same, so that the non-eroded area remaining on the target by each connection is It is possible to erode evenly.

When the magnet assembly composed of a plurality of magnets disposed behind each target to form a magnetic flux in front of each target is reciprocated in parallel to each target during film formation, the magnet assembly moves in one direction. By switching the target by the switching means one or more times, the entire target surface can be sputtered uniformly.

(Best Mode for Carrying Out the Invention)

According to FIG. 2, the sputtering apparatus 2 of this invention is a single | leaf type, the load lock chamber by which the board | substrate S is conveyed and piled up from the wafer cassette (not shown) of an atmospheric atmosphere. 20, a vacuum chamber 21 for sputtering, and a transfer chamber 22 provided between the load lock chamber 20 and the vacuum chamber 21 are provided. The load lock chamber 20, the transfer chamber 22 and the vacuum chamber 21 are connected via a gate valve, respectively. Although not shown, the load lock chamber 20, the vacuum chamber 21, and the transfer chamber 22 are provided with a vacuum pump connected to the vacuum pump and arranged to monitor the vacuum degree.

The load lock chamber 20 is provided with the conveyance arm which conveys the board | substrate holder with which the board | substrate S was mounted. By this conveyance arm, the board | substrate S attached to the board | substrate holder is accommodated in the load lock chamber 20 from the exterior (wafer cassette).

A transfer robot (not shown) is provided in the transfer chamber 22, and after evacuating the load lock chamber 20 to a predetermined vacuum degree, the gate valve is opened, and the substrate is transferred to the transfer chamber 22 vacuum evacuated at the same vacuum degree. (S) is returned. Thereafter, the gate valve between the transfer chamber 22 and the vacuum chamber 21 is closed, and the substrate S is transferred to the vacuum chamber 21 by the transfer robot.

The vacuum chamber 21 is provided with a gas introduction means 23 (see FIG. 3). The gas introduction means 23 is connected to the gas sources 233a and 233b through the gas introduction pipe 232 provided through the mass flow controllers 231a and 231b. A vacuum chamber by a gas source (233a, 233b), the sputtering gas such as argon or, H ₂ O, O _2, reaction gas, and is sealed, these gases such as N _2, the mass flow controller (231a, 231b) ( 21 may be introduced at a constant flow rate.

The target assembly 24 is disposed at a position facing the substrate S conveyed in the vacuum chamber 21. The target assembly 24 has six targets 241a to 241f which are formed substantially in a rectangular shape. These targets 241a-241f are manufactured by a well-known method according to the composition of the film | membrane formed on a board | substrate, such as ITO, Al alloy, and Mo, and the cooling backing plate (not shown) is joined.

Further, the targets 241a to 241f are disposed in parallel with the gap D1 so as to be positioned on the same plane parallel to the substrate S. As shown in FIG. The interval D1 is set to a distance at which plasma is generated in the spaces between the side surfaces of the targets 241a to 241f so that the side surfaces of the targets 241a to 241f are not sputtered. This space | interval D1 is 1-10 mm, Preferably it is 2-3 mm. Since the targets 241a to 241f are disposed close to each other, the sputtered particles reach the entire surface of the substrate S disposed at a position facing the targets 241a to 241f, so that the film thickness distribution can be made uniform. .

The electrodes 242a to 242f and the insulating plate 243 are sequentially attached to the rear surfaces of the targets 241a to 241f, and these are attached to predetermined positions of the target assembly 24, respectively. Three AC power supplies E1 to E3 disposed outside the vacuum chamber 21 are connected to the electrodes 242a to 242f, respectively.

The AC power supplies E1 to E3 are connected so as to apply an electric potential to three targets among the targets 241a to 241f provided in parallel. For example, one of the two outputs of the AC power supply E1 is connected to the electrode 242a so as to apply a potential to the target 241a. The other output is branched, and it is connected to the electrodes 242a and 242f so as to provide a switch SW1 as a switching means at this branch point and apply an electric potential to the two targets 241b and 241f. The potential applied by the AC power source may be a sine wave or a square wave. Each switch SW1-SW3 is a rotary control switch, for example, and has control means (not shown), such as a computer, which controls operation | movement of each switch SW1-SW3.

Each of the switches SW1 to SW3 has a contact t1 and a contact t2. In the switch SW1, for example, the contact t1 and the target 241b are connected, and the contact t2 and the target 241f are connected. Connected. Each of the switches SW1 to SW3 switches the targets 241a to 241f for applying a potential from the AC power supplies E1 to E3 by alternately switching the lines between these contacts t1 and t2.

When connected to the contact point t1 by the switches SW1 to SW3, the AC power supply E1 alternately applies a potential to the target 241a and the target 241b, and the AC power supply E2 is connected to the target 241c. The potential is alternately applied to the target 241d, and the AC power supply E3 alternately applies the potential to the target 241e and the target 241f. In this case, when a negative potential is applied from the AC power sources E1 to E3 to one of the targets 241a, 241c, and 241e, these targets 241a, 241c, and 241e serve as cathodes, and the other targets. 241b, 241d, and 241f serve as anodes.

Then, plasma is formed in front of the targets 241a, 241c, and 241e as cathodes, and the targets 241a, 241c, and 241e are sputtered. Depending on the frequency of the AC power sources E1 to E3, potentials are alternately applied to each of the targets 241a to 241f, and sputtered respectively. However, since no plasma is generated above the ends of the adjacent targets 241a to 241f, this portion is not sputtered. And the non-eroded region R remains at the end of each target (see Fig. 4 (a)).

After the predetermined time has elapsed, when the switches SW1 to SW3 are operated to switch the contacts t2, respectively (see Fig. 4 (b)), the AC power source E1 is the target 241a and the target 241f. ) Is alternately applied, the AC power source E2 alternately applies the potential to the target 241b and the target 241c, and the AC power source E3 alternately applies the potential to the target 241d and the target 241e. do. In this case, when a negative potential is applied from the AC power sources E1 to E3 to one of the targets 241a, 241c, and 241e, these targets 241a, 241c, and 241e serve as cathodes, and the other targets. 241b, 241d, and 241f serve as anodes.

Then, plasma is formed in front of the targets 241a, 241c, and 241e as cathodes, and the targets 241a, 241c, and 241e are sputtered. According to the frequencies of the AC power supplies E1 to E3, potentials are alternately applied to the targets 241a to 241f, respectively, to be sputtered. When the lines of the switches SW1 to SW3 are connected to the contact t2, the targets 241a to 241f to which the AC power sources E1 to E3 are connected change to change the line of the switches SW1 to SW3. When sputtering is performed by connecting to t1), plasma is also formed on the non-eroded region R remaining on the targets 241a to 241f, and the non-eroded region R is also sputtered to form the targets 241a to 241f. It is eroded.

It is preferable to perform switching of these switches SW1-SW3 by a fixed period. When switching is performed at a constant cycle, the power supply time to each target 241a to 241f becomes uniform, that is, the generation time of each plasma becomes uniform, so that the targets 241a to 241f can be sputtered for the same time before and after switching. The entire surface can be eroded. Moreover, the predetermined time to perform this switching is suitably determined based on the film formation time, and it is preferable to set so that it may switch over several times during film formation time. When the odd number of times is switched, the number of times of connection to the contact t1 and the number of times of contact t2 become equal, and the non-eroded area R left on each of the targets 241a to 241f by sputtering in each connection. ) Can be eroded evenly, so that the non-eroded region R does not remain upon completion of film formation.

The installation positions of the switches SW1 to SW3 as the switching means are not particularly limited, and the non-eroded region R is applied by applying a potential from the AC power sources E1 to E3 to the adjacent targets 241a to 241f. Even if it remains, the plasma is applied to the non-eroded region R on the targets 241a to 241f by changing the targets 241a to 241f for applying the potential from the AC power sources E1 to E3 by the switches SW1 to SW3. It can be generated. When one output of each AC power source E1 to E3 is connected through two targets and one switch as in this embodiment, even if the switches SW1 to SW3 are switched during film formation, each target 241a to Since the potential is applied from the AC power supplies E1 to E3 with respect to 241f, the occurrence of abnormal discharge can be suppressed and the number of switches provided in the sputtering device can also be minimized, which is preferable to other embodiments described later.

The target assembly 24 is provided with six magnet assemblies 25 positioned respectively behind the respective targets 241a to 241f. Each magnet assembly 25 is formed in the same structure, has a support portion 251 provided in parallel to the targets 241a to 241f, and on the support portion 251, rod-shaped along the longitudinal direction of the target so as to be alternately arranged with different polarities. The central magnet 252 of the top and the peripheral magnet 253 composed of a plurality of magnets are provided to surround the center magnet 252. Each magnet is designed so that the volume at the time of converting the central magnet 252 into the same magnetization is equal to the sum of the volumes at the time of converting the magnetization of the peripheral magnets 253. As a result, a balanced loop-shaped magnetic flux of a closed loop is formed in front of the targets 241a to 241f, and electrons ionized in front of the targets 241a to 241f and secondary electrons generated by sputtering are captured to serve as cathodes. The density of the plasma formed in front of the target can be increased.

However, since the magnet assemblies 25 are also in close proximity to each other, magnetic fields interfere with each other, and the magnetic field by the magnet assembly 25 located at the rear of the targets 241a and 241f at both ends and the target 241c located at the center. , The balance with the magnetic field by the magnet assembly 25 located behind 241d may be disturbed. In this case, the film thickness distribution in the surface of the substrate S cannot be made substantially uniform. For this reason, the auxiliary magnet 26 is provided in the target assembly 24 so that a magnetic field balance can be corrected. This auxiliary magnet 26 has the same polarity as the peripheral magnet 253 of the adjacent magnet assembly 25. And the space | interval of this auxiliary magnet 26 and the peripheral magnet 253 was made the same as the space | interval D2 of each magnet assembly 25. As shown in FIG. The magnetic field balance is improved by providing the auxiliary magnet 26 below the shield plate 261 disposed outside the targets 241a and 241f positioned at both ends.

Since the magnetic flux is formed in front of the targets 241a to 241f by the magnet assembly 25, the density of the plasma located in front of the central magnet 252 and the peripheral magnet 253 is lowered, and the target 241a is achieved. 241f), the portion corresponding to the upper portion of the central magnet 252 having a low plasma density remains as another non-eroded region. There, it is necessary to change the position of the tunnel-shaped magnetic flux, to uniformly corrode the targets 241a to 241f, and to increase the utilization efficiency.

In order to change the position of the tunnel-shaped magnetic flux, the magnet assembly 25 and the auxiliary magnet 253 are provided at predetermined positions on the drive shaft 270, and ball screws 271 are provided on the drive shaft 270 as drive means. In order to move the position of each magnet assembly 25 to the left and right in parallel. The drive means is not limited to mechanical drive means such as the ball screw 271, but an air cylinder can be used. The moving distance of the magnet assembly 25 is not particularly limited as long as the targets 241a to 241f can be eroded uniformly. For example, the magnet assemblies 25 can be moved in parallel at intervals of points A to B, respectively. In addition, the magnet assembly 25 can be moved not only in the left-right direction but also in the longitudinal direction. By moving the magnet assembly 25 in two dimensions in this manner, the targets 241a to 241f can be more uniformly eroded.

The movement of the magnet assembly 25 may be during film formation or after film formation. In the case of movement during film formation, the ball screw 271 is driven during sputtering so that the targets 241a to 241f are eroded evenly, and the magnet assembly 25 at a period of 2.5 mm / sec or more, preferably 4 to 15 mm / sec. That is, the magnetic flux is reciprocated between points A and B.

When the magnet assembly 25 is moved during film formation, it is necessary to switch the switches SW1 to SW3 at least once while the magnetic flux moves in parallel in one direction in order to uniformly erode the targets 241a to 241f. have. As shown in Fig. 5, during the film formation time, when the magnetic flux is set to move in parallel by the driving means 271 so as to make one reciprocation between the points A and B, the magnetic flux is between the points A and B. The switch was set to perform 4 switching in between moving to one direction. The number of times of switching is not particularly limited as long as the target can be eroded uniformly, and may be even or odd times. In any case, if it is possible to switch the odd number of times during the film formation time, the number of connections to the contact t1 and the number of connections of the contact t2 are the same, and each target 241a is caused by sputtering in each connection. Since the non-eroded regions R left on 241f) can be eroded to each other, the target can be eroded uniformly.

In the case of the movement after the film formation, the film formation is completed, the AC power supplies E1 to E3 are stopped, and the discharge is once stopped, and then the substrate S, which is the next film formation target, is provided at a position facing the targets 241a to 241f. At this time, the ball screw 271 is driven to maintain the magnetic flux by moving the magnetic flux in parallel from the point A to the point B, respectively. In this case, the magnet assembly 25 may be moved at least before the next film formation is started. And after film formation of this conveyed board | substrate S is complete | finished, following a same procedure again, a magnetic flux is parallelly moved again. By repeating this operation sequentially, the film can be sequentially formed on the substrate, and the targets 241a to 241f can be eroded uniformly. By moving the magnetic flux after the film formation in this manner, it is possible to suppress the occurrence of the abnormal discharge due to the movement of the magnetic flux during the film formation.

In the present embodiment, it has been described that the magnetic field balance can be corrected by the auxiliary magnet 253. However, the present invention is not limited to this means as long as the magnetic field balance can be corrected. For example, the magnetic field balance may be corrected by increasing the width dimension of only the peripheral magnet or by changing the peripheral magnet 252 to a material having a high magnetic flux density generated from the magnet.

In the present embodiment, a means for mechanically switching the connection between the AC power source and the target is provided. However, the present invention is not limited thereto, and for example, an insulated gate bipolar transistor (hereinafter referred to as an insulated gate bipolar transistor) is used. You may install it. When this IGBT is used, the switching cycle can be shorter than when switching mechanically. For example, in the case of switching by a switch, the period is several seconds or more, but in the case of using this IGBT, the period can be switched from several µsec to several msec. However, switching to a timing shorter than the discharge period of the AC power supply does not produce the effect of the present invention, and therefore it is necessary to make the discharge power of the AC power supply more than the discharge period.

Another connection example of a target and an AC power supply is shown in FIG. Each target 241a-241f is respectively connected to one AC power supply E, and switching means SW1-SW6 are provided between these connections, respectively. First, as shown in Fig. 6A, the switch SW1 connected to the target 241a and the switch SW2 connected to the target 241b are in a closed state, and these targets 241a and 241b are closed. ) Is applied from an AC power supply, and plasma is generated on these targets 241a and 241b. The plasma does not occur above the opposite ends of the targets 241a and 241b, and the non-eroded region R remains in the targets 241a and 241b. The switches SW3 to SW6 connected to the other targets are in the open state, respectively, so that AC power cannot be applied, and these targets are not sputtered.

After the targets 241a and 241b are sputtered for a predetermined time, the switches SW1 to SW3 are switched, respectively, and the switch SW2 connected to the target 241b and the switch SW3 connected to the target 241c are closed. In this case (see Fig. 6 (b)), these targets 241b and 241c are applied with an electric potential from an AC power supply, plasma is formed, and sputtered. Although the non-erosion area | region R existed in the target 241b, plasma generate | occur | produces between the target 241c, and a plasma generate | occur | produces also in the upper part of this non-erosion area | region R, and the non-erosion area | region R is carried out. This is sputtered.

Subsequently, the switches SW1 to SW6 are sequentially switched during film formation, and the potential is applied to each target from an AC power supply so that the plasma moves sequentially on each target to sequentially sputter the targets 241a to 241f. , The non-eroded region R does not remain on the target (see FIG. 6 (c)).

Hereinafter, the method of forming a film in the surface of the board | substrate S using the sputtering apparatus 2 of this invention is demonstrated.

First, the board | substrate S is conveyed in the position which opposes the targets 241a-241f provided in parallel, and vacuum-exhausts the inside of the vacuum chamber 21 by a vacuum exhaust means. Next, a sputtering gas such as Ar is introduced into the vacuum chamber 21 through the gas introducing means 23, and a predetermined film forming atmosphere is formed inside the vacuum chamber 21. In addition, when reactive sputtering is performed, the reaction gas is introduced at a constant flow rate with the introduction of the sputtering gas. As the reaction gas, it can be appropriately selected according to the physical properties of the desired film, for example, at least one gas selected from H ₂ O gas, O ₂ gas, and N ₂ gas is introduced.

Thereafter, positive or negative potentials are applied to the targets 241a to 241f by the AC power supplies E1 to E3 at several kHz to several hundred kHz while maintaining the film forming atmosphere. An electric field is formed on the target 241 as a cathode, plasma is generated in front of the target 241, and the target is sputtered to release sputtered particles. This operation is alternately performed in accordance with the frequency of the AC power supply, and the respective target surfaces are sputtered by switching the switches SW1 to SW3 every predetermined time. Thereafter, the AC power supply is stopped to form the film.

The magnet assembly 25 may be driven by driving the ball screw 271 during film formation, and after the film formation is completed, the AC power supplies E1 to E3 are stopped and the discharge is once stopped. When conveying the board | substrate S which is a film formation object to the position which opposes target 241a-241f, the ball screw 271 may be driven and the magnet assembly 25 may be moved in parallel, ie, the magnetic flux may be moved in parallel.

(Example 1)

In Example 1, the film was formed using the sputtering apparatus shown in FIG. 2 and FIG. 3, and the number of arc discharge generations during film formation was investigated.

It was set to be parallel to the target consisting of 10wt% SnO ₂ (ITO), and the substrate to position the substrate from 150㎜-200㎜ width, length 1700㎜, In ₂ O ₃ having a thickness of 10㎜. The target width was 2 mm each. Behind each target, a magnet assembly having a width of 170 mm, a length of 1570 mm, and a thickness of 40 mm was provided so that the distance to each target was 47 mm, and the driving distance was set to 50 mm by the ball screw 271. As a board | substrate, the glass substrate of width 1000mm, length 1200mm, and thickness 0.7mm was prepared.

After the substrate transfer, vacuum evacuation was performed, and then argon gas was introduced at 240 sccm as the sputtering gas from the gas introduction means 23 to form a film forming atmosphere of 0.67 Pa. As the reaction gas, 2.0 sccm of H ₂ O gas and 1.5 sccm of O ₂ gas were introduced. Each AC power source E1 to E3 has a frequency of 25 kHz, and gradually raises the power from 0 kW, finally raises it to 15 kW and injects it for 120 seconds. The switch SW1 to SW3 is contacted at a rate of once every 5 seconds. t1 and t2), respectively. Thereafter, the AC power supplies E1 to E3 were once stopped and the magnet assembly was moved when the next substrate S was conveyed. Thus, while forming a film sequentially, the voltage value and the current value were monitored, and the number of occurrences of abnormal discharge (arc discharge) per minute was counted. The target was taken out of the sputtering apparatus and the surface thereof was visually confirmed, and the entire surface of each target was eroded.

(Comparative Example 1)

In Comparative Example 1, using a device in which AC power was connected to two adjacent targets among six targets installed in parallel, a film was formed under the same conditions except for switching of the switches, and the voltage value and current value were monitored. The number of occurrences of the discharge was counted.

The results are shown in Fig. 7, the horizontal axis represents accumulated power (kWh), and the vertical axis represents the number of times of abnormal discharges (times / minute). In Comparative Example 1, as the accumulated power increased, the number of abnormal discharges also increased significantly. On the other hand, in Example 1, even if the accumulated power increased, the number of abnormal discharges hardly increased.

(Example 2)

In Example 2, in-plane uniformity of the film quality when reactive sputtering was performed using the sputtering apparatus shown in FIG. 2 and FIG. 3 was evaluated.

Evaluation of the in-plane uniformity of the film quality was performed by changing the flow rate of the reaction gas at the time of film formation, investigating the flow rate at which the specific resistance was lowered at each point on the film, and using the difference in the flow rate.

By using the same sputtering apparatus as used in Example 1, a plurality of films were formed by changing the flow rate of the reaction gas with Example 1. As the reaction gas, the H ₂ O gas in the 2.0sccm, and O ₂ gas were introduced by varying by 0.2sccm to 0.0 ~ 4.0sccm. Each AC power source E had a frequency of 25 kHz, gradually raised the power from 0 kW, finally raised the power to 15 kW, and after 25 seconds, the AC power was stopped to complete film formation. The film thickness of each obtained film was 1000 kPa. Then, each board | substrate was conveyed to the annealing furnace and air-annealed at 200 degree | times for 60 minutes. The resistivity of the point X corresponding to the upper part of the target 241c on each formed film, and the point Y corresponding to the upper part between the target 241b and the target 241c was measured.

(Comparative Example 2)

Using an apparatus in which an AC power source was connected to two adjacent targets among the six targets arranged in parallel, films were formed and annealed under the same conditions as in Example 2 to form films on the substrate S, respectively. Also about each film formed, specific resistance was measured at the two points of the point (X) and the point (Y), respectively.

8, the horizontal axis represents the flow rate (sccm) of the O ₂ gas, and the vertical axis represents the specific resistance (μΩcm) at each point.

8A shows the measurement result of Comparative Example 2. FIG. The specific resistance value at the point X shown by the solid line was the lowest when the flow rate of the O ₂ gas was 0.5 sccm, and was 255 µcm. In the point (Y) as shown by a broken line, when in the flow rate of O ₂ gas 2.0sccm resistivity of the low, was 253μΩ㎝. The difference in the flow rate of the O ₂ gas having the lowest specific resistance at the points X and Y was significantly different at 1.5 sccm. In Comparative Example 2, it was found that the film quality was not uniform in the substrate surface.

In comparison to this, the second embodiment shown in Fig. 8 (b) for example, and that the specific resistance in the point (X) indicated by the solid line in the lower 250μΩ㎝ when the flow rate of O ₂ gas 1.2sccm, points indicated by the dotted line ( In Y), the specific resistance was lowest at 248 µcm, when the flow rate of the O ₂ gas was 1.4 sccm. In Example 2, the difference in the flow rate of the O ₂ gas at which the specific resistance is lowest at the points X and Y is 0.2 sccm, which is smaller than the difference in the flow rate of the conventional apparatus, and the film quality in reactive sputtering is reduced. It turned out that uniformity in surface is improving.

In the sputtering apparatus of the present invention, by switching the connection between the AC power source and the target by the switching means, the non-eroded region does not remain on the target, and the uniformity of the film quality of the formed film is further improved. Accordingly, the present invention is applicable to the field of manufacturing flat panel displays with large screens.

According to the sputtering apparatus of this invention, when a non-erosion area | region does not remain on a target and reactive sputtering is performed, the outstanding effect that the film | membrane quality of the formed film is uniform can be achieved.

Claims (7)

Three or more targets arranged in parallel at predetermined intervals in the vacuum chamber, and an AC power supply alternately applying a negative potential, an electrostatic potential, or a ground potential to each target, and branching at least one of the outputs from the AC power supply. A sputtering device, comprising: switching means for switching a target to which a potential is applied from an AC power source between each target connected to two or more targets and connected to the branched output. The method according to claim 1, A sputtering device comprising: a magnet assembly composed of a plurality of magnets arranged behind the respective targets so as to form a magnetic flux in front of each target; and drive means for driving the magnet assemblies so that the magnetic fluxes are moved in parallel with the target. Device. The method according to claim 2, A sputtering apparatus, characterized by providing magnetic flux density correction means for making the density of magnetic flux formed by each magnet assembly uniform. In the case where the substrate is sequentially conveyed to a position facing three or more targets arranged in parallel at a predetermined interval in the vacuum chamber, and an alternating potential and a potential or ground potential are alternately applied from the AC power supply to each target, the AC power supply. Sputtering characterized in that a film is formed on the surface of a substrate by generating a plasma on the target while switching a target for applying a potential from an alternating current power source between two or more targets connected by branching at least one of the outputs from the target. Way. The method of claim 4, The target is switched over at a fixed cycle after the start of film formation. The method according to claim 4 or 5, A sputtering method characterized in that the switching by the switching means is performed an odd number of times when two targets are connected by branching the output of the AC power supply. The method according to claim 4 or 5, When the magnet assembly composed of a plurality of magnets disposed behind each target to form a magnetic flux in front of each target is reciprocated in parallel to each target during film formation, the magnet assembly moves in one direction. And the target is switched at least once.

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