JPH11200037A - Production of thin film and sputtering device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device and a method capable of fixedly holding sputtering voltage and capable of uniformizing the film quality of a thin film in a DC sputtering device provided with a reciprocating driving mechanism of a sputtering magnet for forming a thin film on a substrate of a large area or a thin film producing method thereby. SOLUTION: In the case that a sputtering magnet 2 comes to the vicinity of both edges of the reciprocation thereof, by the influence of a shield 16 shielding the periphery of a target board 3, plasma discharge impedance and sputtering voltage increase. Then, the detection of the increase of the voltage is executed, and in accordance with the detected increased value, the height position of the sputtering magnet 2 is lowered, and the distance between the sputtering magnet 2 and the target board 3 is reduced by a prescribed amt. In this way, the discharge impedance is lowered, and the sputtering voltage is reduced to the set value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a method for producing a thin film of a metal or the like on a substrate by DC sputtering and an apparatus therefor. In particular, the present invention relates to a method and an apparatus for manufacturing a metal thin film used in a manufacturing process of an array substrate of a flat panel display device.

[0002]

2. Description of the Related Art As a method of forming a thin film of a metal or the like on a substrate, a DC method capable of efficiently producing a high-quality thin film is used.
Sputtering methods are widely used.

[0003] Regarding an apparatus for performing DC sputtering,
An example of a magnetron type (DC magnetron sputtering apparatus) will be described with reference to the schematic diagram of FIG.

[0004] In the example shown in the figure, the sputtering chamber 10 is decompressed.
0, a substrate 103 on which a thin film is to be deposited is placed on a lower mounting table (susceptor) 114, and a target plate 113 serving as a source of a thin film material is provided on a support plate (backing plate) above the sputtering chamber 100. It is fixed. Thus, the substrate 103 and the flat target plate 113 are arranged to face each other from above and below. On the back side of the target plate, a sputter magnet 102 is arranged in close proximity from above.

The negative electrode of the DC power supply 112 is connected to the cable wiring 11
0, and the target plate 11 via the backing plate.
3 and the positive electrode of the DC power supply 112 is connected to the cable wiring 1
10 are connected to the mounting table 114 of the substrate and the ground wire 115. Further, the pressure in the sputtering chamber 100 is reduced,
A sputtering gas such as an argon gas is introduced.

A target plate 113 is supplied by a DC power supply 112.
When a negative voltage of several hundred volts is applied between the substrate mounting table 114 and the substrate mounting table 114, plasma is generated by magnetron discharge, and the sputtering gas is ionized. Then, the ions are accelerated and collide with the target plate 113, so that target atoms are sputtered (repelled) and deposited on the substrate.

[0007] Such DC sputtering is used, for example, for forming a metal thin film on an array substrate of a flat panel display device. In particular, DC sputtering is generally used in manufacturing an array substrate of an active matrix type liquid crystal display device in which a switch element is arranged for each display pixel.

Active matrix type liquid crystal display devices are widely used in notebook PCs, car navigation devices, ultra-small TVs, etc. due to their excellent performance such as low power consumption and high image quality.

An active matrix type liquid crystal display device comprises:
A liquid crystal layer is held between an array substrate and a counter substrate via an alignment film. In the array substrate, a plurality of signal lines and scanning lines are arranged in a grid on a transparent insulating substrate such as glass or quartz, and amorphous silicon (hereinafter abbreviated as a-Si: H) is provided at each intersection. (Hereinafter abbreviated as TFT) using a semiconductor thin film of the above. And the gate electrode of the TFT is connected to the scanning line,
The drain electrode is electrically connected to each signal line, and the source electrode is electrically connected to a transparent conductive material constituting the pixel electrode, for example, a layer of ITO (Indium-Tin-Oxide).

In manufacturing an array substrate of an active matrix type liquid crystal display device, for example, signal lines and TFTs are used.
The first conductive layer pattern including the gate electrode and the second conductive layer pattern including the scanning line and the source / drain electrodes of the TFT are formed by DC sputtering and subsequent patterning.

In the process of manufacturing a thin film for manufacturing an array substrate of a flat display device as described above, the film thickness distribution of a thin film deposited on a glass substrate having a large area (for example, 550 mm × 650 mm) is uniform. In order to achieve this, a rectangular rod-shaped sputter magnet 102 that is long in front and back is reciprocated right and left during the sputtering process. During the reciprocating movement, the distance between the sputter magnet 102 and the backing plate 116 is kept constant.

Here, the target plate 113 is welded and held to a copper backing plate 116. The peripheral edge of the target plate 113 and the four peripheral portions where the backing plate 16 is exposed are formed by a shelf-shaped shield. 11
7. Prevents ions from colliding with the backing plate 116 and mixing of copper into the formed thin film, and prevents generation of particles (dust particles) due to the target material 113 being deposited on the backing plate 116 and peeling off. To do that.

[0013]

As shown in FIG. 6, when the sputter magnet 102 is at both ends of its reciprocating movement, the plasma area (the area of the target where the plasma collides) is shielded by the shield. Will decrease. Therefore, the discharge impedance increases. As a result, in a normal sputtering apparatus of the constant power control type, the sputtering voltage increases.

FIG. 7 is a schematic graph showing the variation over time of the sputtering voltage.

When the sputter magnet 102 comes to both ends of the reciprocating motion, the sputter voltage sharply increases, and the graph shows a "sputter voltage horn" (having a horn length of ΔV). When the sputtering voltage fluctuates, the film quality of the thin film formed on the substrate 3 changes. Therefore, the region on the substrate 3 corresponding to the “sputter voltage horn”, that is, the substrate 3
The film quality is different from the other regions at the left and right ends.

On the other hand, regardless of whether the sputter magnet is reciprocated, when the sputtering is repeated and the target is consumed, the target-magnet distance (T / M) is reduced by the thickness of the target. Will decrease. As a result, the discharge impedance is reduced, and as a result, the sputtering voltage is reduced in the constant power control type sputtering apparatus.

In view of the above problems, the present invention provides a method for producing a thin film by magnetron type DC sputtering and a sputtering apparatus therefor, and more particularly, a sputter magnet for forming a thin film on a large-area substrate. Provided with a reciprocating mechanism of (1), wherein the sputtering voltage can be kept constant, whereby the quality of the generated thin film can be made uniform.

[0018]

In the method of manufacturing a thin film according to the present invention, a predetermined sputtering voltage is applied between a target plate and a substrate, and a sputtering magnet is reciprocated in parallel with the target plate. In a method of manufacturing a thin film in which a thin film is deposited on a substrate by DC sputtering by moving, when detecting that the sputtering voltage fluctuates from its reference voltage, the sputter magnet reduces the fluctuation of the sputter voltage. And adjusting the distance between the sputter magnet and the target plate by moving the sputter magnet in a direction substantially perpendicular to the target plate.

Further, in the DC sputtering apparatus according to the second aspect, a processing chamber in which a substrate can be disposed, a target plate disposed in the processing chamber, and a reciprocating support parallel to the target plate. A sputter magnet, a voltage detecting means for detecting a sputter voltage, and a magnet-target for adjusting the distance between the sputter magnet and the target plate by moving the sputter magnet in a direction substantially perpendicular to the target plate. A distance adjuster, and the magnet-
A DC sputtering apparatus includes a magnet-target distance control unit that controls and reduces a target distance adjustment unit.

With such a configuration, the fluctuation of the sputtering voltage can be made sufficiently small, and the quality of the thin film can be made uniform. Also, this hardly increases the manufacturing cost.

According to a third aspect of the present invention, in the DC sputtering apparatus, a processing chamber in which a substrate can be placed, a target plate placed in the processing chamber, and a peripheral portion of the target plate, A shelf-shaped shield for preventing plasma collision, a sputter magnet supported so as to be able to reciprocate in parallel with the target plate, and moving the sputter magnet in a direction substantially perpendicular to the target plate to form the sputter magnet; Magnet for adjusting the distance between the magnet and the target plate
The inter-target distance adjusting unit and the magnet-target so as to reduce the distance between the sputter magnet and the target plate while the sputter magnet is positioned in a region where the target plate is shielded by the shelf-shaped shield. The DC sputtering apparatus includes a magnet-target distance control unit that controls the distance adjustment unit.

According to such a configuration, when sputtering is performed on a large-area substrate, the fluctuation of the sputtering voltage when forming the film on both ends of the substrate can be sufficiently reduced, and thus the thin film to be manufactured can be formed. Can be made uniform over the entire substrate.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for manufacturing a thin film by DC magnetron sputtering and a sputtering apparatus for the same according to the present invention will be described with reference to FIGS. I do.

FIG. 1 is a longitudinal sectional perspective view schematically showing a basic structure of a sputtering chamber 1 in a DC magnetron sputtering apparatus according to an embodiment.

A substrate mounting table 14 is provided below the sputtering chamber 1, on which a large-area glass substrate 3 (550 mm × 650 mm) on which a thin film is to be deposited is mounted. Above the sputtering chamber 1, a target plate 13 serving as a source of the thin film material is fixed to the lower surface of the backing plate 16 by welding.

As shown in FIG. 1, as the flat target plate 13 which is arranged to face the glass substrate 3 on the mounting table 14, a plate having an area approximately equal to that of the glass substrate 3 is used. In the illustrated example, a sponge magnet 2 in which a set of three rectangular bars long in the front and rear directions is fixed to the lower surface of a horizontally arranged beam (beam) is used.

Here, the target plate 13 is welded and held to a copper backing plate 16, and the peripheral edge of the target plate 13 and the four peripheral portions where the backing plate 16 is exposed are formed by a shelf-shaped shield. 17. The shield 17 includes the backing plate 1
6, which prevents ions from colliding with the silicon and causes contamination of the formed thin film with copper, and also prevents generation of particles (dust particles) due to the target material 13 being deposited on the backing plate 16 and peeling off. It is.

The sputtering chamber 1 is of a single-wafer type. That is, the glass substrates 3 are set one by one, and a thin film is deposited thereon. The setting and removal of the glass substrate 3 with respect to the substrate mounting table 14 are performed in a state where the substrate mounting table 14 is pulled down. The substrate mounting table 14 is connected and supported on a vertically movable cylinder 14a.

Although not shown, the negative side of the DC power supply is connected to the backing plate 16 and the positive side is
4 and ground wire.

As shown by the arrow in FIG.
In the upper magnet chamber 25, the sputter magnet 2 reciprocates in the left and right horizontal directions during the sputtering process. Also, when it comes to both ends of the reciprocating motion, that is, the area corresponding to the shelf-shaped shield, it is pulled down,
When the two ends are separated, a vertical movement is performed to return to the original height.

When the sputter magnet 2 is shielded by the shield 17, the discharge impedance increases due to the decrease in the plasma area. At this time, by lowering the sputter magnet 2 toward the target plate 3, An increase in discharge impedance can be avoided. As a result, even when the power acting between the anode and the cathode of the sputtering chamber 1 is a constant power control method, the fluctuation of the sputtering voltage can be sufficiently suppressed.

FIG. 2 is a cutaway perspective view of the magnet chamber 25 above the sputter chamber 1 for schematically showing the structure of the apparatus for performing the horizontal reciprocating motion and the vertical motion of the sputter magnet as described above.

FIG. 2 shows a portion above the backing plate 16 to which the target 13 is fixed. An insulating plate 19 made of Teflon is provided on the upper surface of the backing plate 16.
The bottom plate 28 of the magnet chamber 25 is arranged via the. The bottom plate 28 is formed integrally with the cathode cover 18 which is a housing forming a side wall and a ceiling of the magnet chamber.

The magnet support beam 20 to which the sputter magnet 2 is fixed is supported by a horizontal moving device 25A for reciprocating the magnet 2 left and right and a vertical moving device 25B for adjusting the height of the magnet 2 connected in series. It is supported by being suspended from the cathode cover 18 through the structure.

The horizontal moving device 25A includes a servo motor 2
1, a horizontal bolt shaft 22 directly connected thereto, a vertically movable frame 24 for holding them, and a magnet support plate 23 having a nut hole 23a at the center for screwing with the horizontal bolt shaft 22. Magnet support plate 2
3, the lower surface is fixed to the upper surface of the magnet support beam 20,
The magnet support beam 20 is suspended from the horizontal bolt shaft 22.

The vertical movable frame 24 includes a right vertical plate portion 24a that supports the servomotor 21 and the right end of the horizontal bolt shaft 22 and a left vertical plate portion 24c that supports the left end of the horizontal bolt shaft 22. A frame-like portion 2 connecting the lower ends of the vertical plate portions 24a, 24c
4b.

When the servo motor 21 operates and the horizontal bolt shaft 22 rotates, the magnet support plate 23
Is moved to the left or right. At this time, the upper surface of the magnet support beam 20 and the front and back portions of the frame-shaped portion 24b slide.

The vertical moving device 25B includes the cathode cover 1
8, a vertical bolt shaft 29 directly connected to the servomotor 26, and a horizontal plate portion 24d of a vertically movable frame having a nut hole screwed to the vertical bolt shaft 29 at the center thereof. This horizontal plate part 2
4d, the right end is connected to the upper end of the left vertical plate portion 24c.

When the servo motor 26 is operated to rotate the vertical bolt shaft 29, the vertically movable frame 24
The whole is raised or lowered.

As described above, the entire vertical movable frame 24 and horizontal moving device 25A, the sputter magnet 2 and the magnet support beam 20 are all suspended by one vertical bolt shaft 29. The vertically movable frame 24 is suspended by a vertical plate portion 24c at the left end.

Therefore, in order to absorb the rotational moment of the vertically movable frame 24 in the clockwise direction, the support plate 27 serving as a hook bar is formed by the magnet chamber 2.
5 and the left vertical plate portion 24 of the vertically movable frame 24
c. The support plate 27 is fixed to the cathode cover 18, and the rail receiving portion 27a at the tip thereof is
The left vertical plate portion 24c is engaged with a vertical rail-shaped projection 24e provided on the left surface of the left vertical plate portion 24c.

When the vertically movable frame 24 is moved up and down, these rail-like projections 24e and rail receiving portions 27a
Is slid. By providing such a guide and support mechanism in the vertical movement device 25B, the horizontal movement of the vertically movable frame 24 during vertical movement or the like is prevented.

As described above, according to the magnet moving devices 25A and 25B of this embodiment, the movement in the horizontal direction and the vertical direction is performed according to the rotational drive by the servo motor 21, so that precise position control is possible. It is.

Further, since the horizontal moving device 25A is suspended by the vertical moving device 25B to perform vertical movement, and a guide mechanism for preventing the horizontal movement of the vertical movable frame 24 is provided, the vertical movement of the magnet is the simplest. It can be performed by the device, and has no adverse effect on the horizontal movement and the setting of the horizontal position. Therefore, even if a vertical moving device is added, the cost for the vertical moving device can be minimized, and the reliability and durability of the moving device can be kept high.

FIG. 3 shows an electric drive system for performing vertical drive. A sputter voltmeter 51 for measuring a sputter voltage is provided between the DC power supply and the cathode / anode electrodes of the sputter chamber 1, and continuously measures the sputter voltage during operation of the DC sputtering apparatus. On the other hand, a desired sputtering voltage during normal operation is set and input to the reference voltage generation circuit 52 in advance as a reference voltage value. The output value from the sputter voltmeter 51 and the output value from the reference voltage generation circuit 52 are always input to the comparator 53, and the increase / decrease value of the sputter voltage with respect to the reference voltage value is output. The output from the comparator 53 is amplified by an amplifier 54 and input to a servo motor drive circuit 55 that drives the servo motor 26. In this way,
The servo motor 26 is driven according to the fluctuation width of the sputtering voltage 51. When the sputter voltage is higher than the reference voltage, the rotational drive is performed in a direction in which the entire vertically moving frame is lowered, and in the opposite case, the rotational drive is performed in the reverse direction. The time required from the detection of such a change in sputter voltage to the start of driving of the servo motor 26 is on the order of microseconds.

FIG. 4 is a schematic plan view showing the layout of the sputtering apparatus and its attachments. In the plan view, six substantially rectangular chambers are arranged so as to surround the central transfer chamber 43 having a substantially regular hexagonal shape. The six chambers are two load lock chambers 41 (vacuum preparatory chambers), one preheating chamber 44, and three sputtering chambers 1. The entrances of these chambers are formed integrally with each side wall of the central transfer chamber 43.

The central transfer chamber 43 and the preheating chamber 44 are depressurized to the same degree of vacuum as the sputter chamber 1, and transfer to the outside is performed through decompression in the load lock chamber 41 or venting to atmosphere (return to atmospheric pressure). Done. The loading and unloading of the glass substrates 3 between the outside and the load lock chamber 41 are performed in a state where a plurality of glass substrates 3 are mounted on a cassette. Argon gas, which is a sputtering gas,
The gas is supplied from the gas cylinder 46 to the sputtering chamber 1 via the flow controller 47. On the other hand, the central transfer chamber 43
The glass substrate 3 is moved by the robot arm 42 of the load lock chamber 41 → the preheating chamber 44 → the sputtering chamber 1 →
They are transferred in the order of the load lock chamber 41. In this embodiment,
The glass substrate 3 is heated to 200 ° C. in the preheating chamber 44 and transferred to the sputtering chamber 1.

Next, on a glass substrate 3 for an array substrate,
Molybdenum-tungsten alloy thin film for forming gate lines and scanning lines of TFTs (molybdenum 50% by weight,
Hereinafter, a specific example in which a Mo-W film is deposited to a thickness of 300 nm will be described.

When depositing the thin film, the reference voltage of the sputtering voltage was set to 550 V, argon (Ar) gas was used as the sputtering gas, and the degree of pressure reduction in the sputtering chamber 1 was 0.6 Pa. The temperature of the substrate mounting table 14 was set to 200 ° C. The sputter magnet 2 was reciprocated three times to make the film thickness uniform.

Table 1 shows the fluctuation of the sputtering voltage during the deposition of the thin film and the sheet resistance (area resistivity, sh) of the obtained thin film.
3 shows the results of measuring the distribution of eet resistivity).

[0051]

[Table 1] As can be seen from the table results, according to the method of the example,
The fluctuation width of the sputtering voltage can be made less than 1/10 of the fluctuation width seen in the conventional technique (comparative example).
The variation in sheet resistance could be reduced to about 2/3. The less variation in sheet resistance means that the quality of the thin film is more uniform. The sheet resistance itself is also reduced, because the average value is reduced as the sheet resistance does not increase due to the increase in the sputtering voltage.

Further, the first metal layer including the scanning lines and the gate lines is formed by using the same sputtering method as in the above specific example according to Table 1, and the other elements are the same as those of the conventional example. As a result, there was no etching shape defect due to poor film quality, and a high production yield could be secured.

As described above, by providing a mechanism for detecting the fluctuation of the sputtering voltage and automatically adjusting the distance between the sputter magnet and the target plate, the uniformity of the quality of the thin film produced by sputtering can be improved. The performance was greatly improved.

In the above embodiment, the sputter magnet is moved up and down by detecting the fluctuation of the sputter voltage. However, the horizontal moving device is so moved as to lower the sputter magnet only when it comes to the end of the reciprocating motion of the sputter magnet. A configuration in which the vertical movement device 25B is driven in accordance with the movement of 25A may be adopted.

At this time, with respect to the fluctuation of the magnet-target distance due to the consumption of the target material 13, the fluctuation of the sputtering voltage is detected at regular intervals, and the setting of the height position in the vertical moving device 25B is performed. It can respond by changing.

[0056]

According to the DC sputtering apparatus of the magnetron type or the method of manufacturing a thin film using the same, the sputtering voltage can be easily kept constant, and the quality of the thin film can be made uniform.

Particularly, in a DC sputtering apparatus provided with a reciprocating mechanism of a sputter magnet for forming a thin film on a substrate having a large area, the sputtering by the action of a shield for shielding the peripheral portion of the target at both ends of the reciprocating movement. An increase in voltage can be sufficiently suppressed, and the film quality of the formed thin film can be made uniform.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional perspective view schematically showing a basic configuration of a sputtering chamber in a DC magnetron sputtering apparatus according to an embodiment.

FIG. 2 is a cutaway perspective view of an upper portion of a sputter chamber, schematically showing a device for performing a horizontal reciprocating motion and a vertical motion of a sputter magnet.

FIG. 3 is a block diagram illustrating a control drive system that performs vertical drive of a sputter magnet.

FIG. 4 is a plan view schematically showing a layout of a sputtering device and an auxiliary device thereof.

FIG. 5 is a conceptual diagram schematically showing a basic configuration and a basic wiring of a sputtering chamber.

FIG. 6 is a longitudinal sectional perspective view schematically showing a basic configuration of a sputtering chamber in a conventional DC magnetron sputtering apparatus.

FIG. 7 is a graph showing a change in sputtering voltage in a conventional DC magnetron sputtering apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sputter chamber 2 Sputter magnet 3 Glass substrate 11 Arc discharge interruption device 12 DC power supply 13 Target 14 Substrate mounting table 15 Ground wire 16 Backing plate 17 Shelf-shaped shield 18 Cathode cover 19 Teflon insulating plate 20 Magnet support beam (beam) DESCRIPTION OF SYMBOLS 21 Horizontal drive servomotor 22 Horizontal bolt shaft 23 Magnet support plate 24 Vertically movable frame 24a Rail-shaped projection 25 Magnet chamber 25A Horizontal movement device 25B Vertical movement device 26 Vertical drive servomotor 27 Rail guide support plate 27a Rail receiving portion 28 Rail Guide 29 Vertical Bolt Shaft

Claims (4)

[Claims] 1. A method in which a predetermined sputtering voltage is applied between a target plate and a substrate, and a sputtering magnet is reciprocated in parallel with respect to the target plate.
In a method of manufacturing a thin film, wherein a thin film is deposited on a substrate by sputtering, when detecting that the sputtering voltage has fluctuated from its reference voltage, the sputter magnet is used to reduce the fluctuation of the sputtering voltage. A method of adjusting the distance between the sputter magnet and the target plate by moving the sputter magnet in a direction substantially perpendicular to the thin film. 2. A processing chamber in which a substrate can be placed, a target plate placed in the processing chamber, a sputter magnet supported reciprocally in parallel with the target plate, and a sputter voltage is detected. A magnet-target distance adjusting unit that adjusts a distance between the sputter magnet and the target plate by moving the sputter magnet in a direction substantially perpendicular to the target plate; and a variation in the sputter voltage. And a magnet-target distance control unit that controls and reduces the magnet-target distance adjustment unit. 3. A processing chamber in which a substrate can be placed, a target plate placed in the processing chamber, and a shelf-like plate placed around the periphery of the target plate to prevent collision of plasma with the target plate. A shield, a sputter magnet supported so as to be able to reciprocate in parallel with the target plate, and moving the sputter magnet in a direction substantially perpendicular to the target plate to reduce a distance between the sputter magnet and the target plate. A magnet-target distance adjusting unit that adjusts the distance between the sputter magnet and the target plate while the sputter magnet is positioned in a region where the target plate is shielded by the shelf-shaped shield; Between the magnet and the target that controls the magnet-target distance adjustment unit DC sputtering apparatus, characterized in that it comprises a release control unit. 4. The DC sputtering apparatus according to claim 2, wherein the magnet-target distance adjusting unit includes: a servo motor fixed to the processing chamber;
DC sputtering, comprising: a shaft rotatably driven by the shaft, a hole engaged with the shaft, and a movable member moved in accordance with the rotation driving, and supporting the sputter magnet via the movable member. apparatus.