KR20130129859A - Sputtering method - Google Patents

Abstract

Provided is a sputtering method, which effectively suppresses a generation of a reverberating film thickness distribution or a thin film distribution when a target is sputtered and deposited. The opposite side with a substrate (W) of each target (31-34) is the top, and a leakage magnetic field (M1, M2) of a tunnel shape is formed on the upper direction of the each target by magnet units (41-44), which are arranged in the lower direction of the each target. While the each magnet units relatively are reciprocating toward the X direction about a predetermined stroke target by synchronizing the each magnet units in sputtering, the substrate relatively is reciprocating toward the X direction about the predetermined stroke target simultaneously. The each magnet units and the substrate are moved toward the directions, which are contrary to each other. Time till the each magnet units return to a position from a start point of a reciprocating motion is equal.

Description

Sputtering Method {SPUTTERING METHOD}

According to the present invention, a substrate is disposed in a vacuum chamber in which a target is installed, a sputter gas is introduced into the vacuum chamber, a predetermined power is supplied to the target to form a plasma in the vacuum chamber, and the target is sputtered, and the substrate is opposed to the target. A sputtering method for forming a predetermined thin film on a surface.

As one of the methods of forming a predetermined thin film on the surface of a substrate to be treated such as glass, there is a sputtering method (hereinafter referred to as a "sputtering") method. In particular, a magnetron type sputtering method is particularly suitable for the rear of the target (sputter surface and orientation). By the tunnel-shaped magnetic flux from the magnet unit disposed on the side of the target unit, electrons ionized in front of the sputtering surface of the target and secondary electrons generated by sputtering are captured, thereby increasing the electron density in front of the electrons And the plasma density can be increased by increasing the collision probability of the sputter gas consisting of the rare gas introduced into the vacuum chamber with the gas molecules. For this reason, there exists an advantage that the film-forming speed | rate can be improved, and in recent years, it is used for film-forming for the board | substrate with a large area similarly to the glass substrate for FPD manufacture.

Here, as a sputtering apparatus which forms into a film with a favorable film thickness distribution with respect to a large area board | substrate, it is known that the several target of the same shape was provided in the vacuum chamber side by side at equal intervals. In this case, since sputter particles are not emitted from the areas between the targets, when a predetermined thin film is formed on the surface of the substrate, the film thickness distribution of the thin film and the film quality distribution during reactive sputtering are waved (for example, the film thickness). In the case of a distribution, it is likely to be non-uniform, such as repeated thick and thin portions of thin thickness at the same period. If there is a film thickness distribution or a film quality distribution that is waved in this way, for example, when a transparent electrode (ITO) is formed on a glass substrate, the liquid crystal is encapsulated, and the FPD is produced, there is a defect that a stain occurs on the display surface.

Accordingly, during sputtering, each target is relatively reciprocated in a predetermined stroke, integrally and in parallel with the substrate, thereby changing the area where sputter particles are not emitted, i.e., sputter particles are released from the target over the entire substrate. It is known to improve the nonuniformity of the film thickness distribution and the film quality distribution by facing the region. In this case, in order to further increase the uniformity of the film thickness distribution and the film quality distribution, each magnet unit is also relatively reciprocated by a predetermined stroke in parallel with the substrate, thereby changing the position of the tunnel-shaped magnetic flux which increases the sputter rate. (For example, refer patent document 1). However, even in this conventional example, it has been found that the film thickness distribution and the film quality distribution which locally wave very small cannot be sufficiently improved in other words, which cannot sufficiently improve the film thickness distribution and the film quality distribution that wave very little over the entire substrate. Therefore, the inventors and the like have earned the knowledge that, by intensively studying and synchronizing the reciprocating motion of the target (or substrate) with the reciprocating motion of the magnetic unit, it is possible to effectively suppress the occurrence of waving film thickness distribution and film quality distribution.

Patent Document 1: Japanese Patent Application Laid-Open No. 2004-346388 (See, for example, the description of the claims)

In view of the above, the present invention effectively suppresses the occurrence of a film thickness distribution or a film quality distribution when sputtering targets and forming a film, especially when sputtering a film having a plurality of targets installed side by side at a predetermined interval. It is an object of the present invention to provide a sputtering method.

In order to solve the above problems, a substrate is disposed in a vacuum chamber in which a target is installed, a sputter gas is introduced into the vacuum chamber, power is supplied to the target to form a plasma in the vacuum chamber, and the target is sputtered to form a plasma. In the sputtering method of forming a film on the opposing surface, a plurality of magnet units are arranged side by side at a predetermined interval in the X direction, which is one direction of the target, below the target, with the opposing surface side of the target facing up. The magnet unit forms a tunnel-shaped leaking magnetic field above the target, and during sputtering, the respective magnet units are synchronously reciprocated relative to the target with a predetermined stroke in the X direction while synchronizing, and the substrate is moved in the X direction. Reciprocating relative to the target with a predetermined stroke, and opposite directions of the respective magnetic units and the substrate A relative movement Sikkim and at the same time, characterized in that equally the respective magnet unit and the time until the substrate reaches the return position from the starting point of the reciprocation motion.

According to the present invention, the time between each magnet unit and the substrate is moved relative to the opposite direction, and the time until the magnet unit and the substrate reach the return position from the starting point of the reciprocating motion is equalized. As a result, it is opposed to the region where the sputter particles are released from the target, and as a result, the film thickness distribution and the film quality distribution which are waved locally very small are not left, and the variation in the film thickness distribution and the film quality distribution can be effectively suppressed. have.

In the present invention, the target is configured by arranging a plurality of target materials of the same shape side by side at equal intervals in the X direction, and having a magnetic unit corresponding to each target material, respectively, between the centers of adjacent targets. It is preferable to make the distance equal to the sum of the stroke of the magnet unit and the stroke of the substrate. According to this, the area | region in which sputtering particle | grains are discharged | emitted from a target becomes more uniformly opposed over the whole board | substrate, and it can suppress the nonuniformity of a film thickness distribution and a film quality distribution more effectively. In addition, in this invention, the target which has the same shape shall mean that the target shape in plan view is the same, and the thickness of each target may mutually differ.

According to the present invention, when sputtering a target and forming a film, in particular, when sputtering and forming a film having a plurality of targets installed side by side at a predetermined interval, it is possible to effectively suppress the occurrence of a waving film thickness distribution or a film quality distribution.

BRIEF DESCRIPTION OF THE DRAWINGS It is typical sectional drawing explaining the structure of the sputter apparatus of this invention.
FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1.
3 (a) to 3 (c) are diagrams typically showing the substrate W and the magnet unit moving in opposite directions.
(A) is a graph of the measurement result of the invention experiment, (b) the measurement result of the comparative experiment 1, and (c) the measurement result of the comparative experiment 2.

Hereinafter, referring to the drawings, a plurality of targets having the same shape are installed side by side at a predetermined interval in the sputter chamber, and among the targets installed side by side, AC power is applied to the pairs to sputter each target and at the same time, the sputter chamber The sputter apparatus SM of embodiment of this invention is demonstrated to an example which introduce | transduces an oxygen gas and forms a metal oxide film into the board | substrate which should be processed, such as a glass substrate, by the metal film which consists of a target material, or a reactive sputter.

As shown in FIG. 1 and FIG. 2, the magnetron type sputter apparatus SM is provided with the vacuum chamber 1 which delimits the sputter chamber 1a. The exhaust port 11 is provided in the wall surface of the vacuum chamber 1, and the exhaust port 11 is connected to the exhaust pipe 12 which connects to the vacuum exhaust means P, such as a rotary pump and a turbo molecular pump, and a sputter chamber (1a) The inside can be vacuum sucked to maintain a predetermined degree of vacuum. The gas introduction means 2 is provided in the wall surface of the vacuum chamber 1. The gas introduction means 2 continuously connects to a gas source (not shown) through the gas pipes 22a and 22b in which the mass flow controllers 21a and 21b are opened, respectively, and when sputtering gas or reactive sputtering made of rare gas such as argon Can be introduced at a constant flow rate. As the reaction gas, a gas containing oxygen, nitrogen, carbon, or hydrogen, ozone, water or hydrogen peroxide, or a mixed gas thereof is used depending on the composition of the thin film to be formed on the substrate W. Hereinafter, the target mentioned later in the sputtering chamber 1a and the board | substrate W oppose, "upper" the direction which will make the direction from a target to a board | substrate, and "bottom" the direction which will go from a board | substrate W to a target. And a direction in which the magnet units are installed side by side in the X direction (left and right directions in FIG. 1), and a direction orthogonal to this is described as the Y direction.

The magnetron sputter electrode C is arrange | positioned at the bottom of the sputter chamber 1a. The magnetron sputter electrode C is located below the four targets 3 ₁ to 3 _{4 of the} substantially rectangular parallelepiped (flat rectangle) installed so as to face the sputter chamber 1a, and below each of the targets 3 ₁ to 3 ₄ . Each of the magnetic units 4 ₁ to 4 ₄ is provided. The number of targets placed side by side is not limited to the above, and the target is a known method depending on the composition of the thin film to be deposited on the substrate W such as Si, Al and its alloys, Mo, or ITO. You can use the one produced by. Further, good and if each target _(31-34) have the same shape in a plan view, or may be respectively different in thickness.

Each of the targets 3 ₁ to 3 ₄ is joined to the backing plate 31 made of copper for cooling the targets 3 ₁ to 3 ₄ via a bonding material such as indium or tin during sputtering. Then, the targets 3 ₁ to 3 ₄ are bonded to the backing plate 31, and in the sputter chamber 1a through the insulator 32 for both vacuum sealing in a state where the targets 3 ₁ to 3 ₄ are placed upward. Is installed. In this case, the upper surfaces of the targets 3 ₁ to 3 ₄ constitute the sputter surface 3a which is sputtered with ions of the sputter gas described later during film formation. The targets 3 ₁ to 3 ₄ are equally spaced in the Y direction in the sputter chamber 1a, while the sputter surface 3a when not in use is located in the same plane parallel to the substrate W. 2, and the shape of each target is designed so that the total area of each sputter surface 3a provided side by side may become larger than the external dimension of the board | substrate W. As shown in FIG.

After arranging the targets 3 ₁ to 3 _{4 in the} sputtering chamber 1a, a plate having an opening 51 facing the targets 3 ₁ to 3 ₄ around each of the targets 3 ₁ to 3 ₄ . Shaped shields 5 are disposed respectively. Each shield 5 is made of aluminum, for example. In addition, two targets 3 ₁ and 3 ₂ and 3 ₃ and 3 ₄ adjacent to each other among the targets 3 ₁ to 3 ₄ installed side by side are paired, respectively, and paired targets 3 ₁ to 3 ₄ . The output Eo from the AC power supply E is respectively connected to 3 ₄ ). At the time of film formation, AC power at a predetermined frequency (for example, 1 Hz to 100 kHz) is input from the AC power supply E to the pairs 3 ₁ to 3 ₄ of each pair.

The magnet units 4 ₁ to 4 ₄ disposed below each backing plate 31 (outside of the sputter chamber 1a) have the same shape, and one magnet unit 4 ₁ will be described as an example. The unit 4 ₁ is provided in parallel with the backing plate 31 and has a supporting plate 41 (yoke) made of a flat plate made of a magnetic material that amplifies the attraction force of the magnet. On the support plate 41, an upper surface outer periphery of the support plate 41 so as to surround the center magnet 42 disposed and positioned on a centerline extending in the longitudinal direction of the support plate 41 and the center magnet 42. Peripheral magnets 43 arranged in a ring shape along the surface of the target side are provided with different polarities. In this case, for example, the sum of the volumes when converting the same magnetization of the central magnet 42 into the same magnetization of the peripheral magnet 43 surrounding the periphery (peripheral magnet: center magnet: Peripheral magnet = 1: 2: 1 (see Figure 1)). As a result, the tunnel-shaped leaky magnetic fields M1 and M2 are balanced, respectively, above the targets 3 ₁ to 3 ₄ . In addition, the center magnet 42 and the peripheral magnet 43 are well-known things, such as a neodymium magnet, These center magnet and the peripheral magnet may be integral, or it is comprised by providing a plurality of magnet pieces of predetermined volume in a row. You may also do it.

The support plate 41 has an outer dimension that is made one round smaller than the outline of the target, and each magnet unit 4 ₁ to 4 _{4 is} connected to the first moving means 6 via each support plate 41. The 1st moving means 6 rotates the feed screw 61 screwed to the nut member 41a provided by hanging in the lower surface of each support plate 41, and this feed screw 61 is rotated in the forward / backward direction. The motor 62 is provided. Then, when the feed screw 61 is rotated and driven, the magnetic units 4 ₁ to 4 ₄ integrally reciprocate in a constant stroke S1 simultaneously with a predetermined speed on the same plane in the X direction along the rotational direction thereof. do. In addition, as shown in FIG. 1, a pair of left and right rails having a feed screw 61 provided on the base plate 63 and extending horizontally over the entire length of the target 41 in the Y direction in the longitudinal direction. It may be slidably engaged with the members 64R and 64L and held by sliders 65R and 65L provided with a drive motor not shown. Then, when the two sliders 65R and 65L are moved in the Y direction in synchronism, the respective magnetic units 4 ₁ to 4 ₄ may be reciprocated in a constant stroke simultaneously with a predetermined speed on the same plane in the Y direction. have. As a result, each of the magnetic units 4 ₁ to 4 ₄ is moved relative to the targets 31 to 34 on which the magnetic units 4 ₁ to 4 ₄ are located immediately above the predetermined starting point. The return is repeated.

Further, the upper portion in the vacuum chamber 1, a holder 7 that protects the substrate (W) supported so as to be opposed to side-by-side installed targets _(31-34) is installed. The holder 7 is provided with a concave portion 71 recessed in correspondence with the outline of the substrate W. On the lower surface of the concave portion 71, the lower surface (film formation surface) of the substrate W is the target 3 ₁ to. A central opening 72 is formed facing the 3 _{4. In} addition, a second moving means 8 is connected to the holder 7. The second moving means 8 has a lower surface of the holder 7. A screw screwed to the nut member 73 provided in the screw member 73, which is installed to penetrate the side wall of the vacuum chamber 1, and a motor 82 for rotationally driving the feed screw 81 in the forward and reverse directions. Then, when the feed screw 81 is driven to rotate, the holder 7 and the substrate W along the rotational direction thereof move on the same plane in the X direction at the same speed and at a constant stroke S2. In this case, the distance between the centers of the adjacent targets 3 ₁ to 3 ₄ (also referred to as the "cathode pitch") Dt is the stroke S1 of each of the magnetic units 4 ₁ to 4 ₄ and the substrate ( W) Straw It is equal to the sum with (S2).

Next, with reference to FIG. 3 further, film-forming by the sputtering method using the said sputter apparatus SM is demonstrated. First, the board | substrate W is set to the holder 7, and the inside of the sputter chamber 1a is vacuum-blowed to predetermined pressure. At this time, the holder 7 is located at the starting point position of the right end of the reciprocating motion, as shown in Figs. 1 and 3A, and each of the magnetic units 4 ₁ to 4 ₄ has It is located at the starting point of the left end. Then, a predetermined sputter gas and a reaction gas are introduced through the gas introduction means 2, and AC power is input to each of the targets 3 ₁ to 3 ₄ which are paired via the AC power supply E, respectively. As a result, the two pairs of targets 3 ₁ and 3 ₂ and 3 ₃ and 3 ₄ fulfill the roles of the positive electrode and the negative electrode, respectively, and above each of the targets 3 ₁ to 3 ₄ , A tunnel-shaped leak magnetic field is formed, and high-density plasma is generated in the form of a rate track passing through a position where the vertical component of the leak magnetic field becomes zero. In the starting position shown in FIG. 3A, since the leakage magnetic field is formed above the left portions of the targets 3 ₁ to 3 ₄ , the left portions of the targets 3 ₁ to 3 ₄ are each sputtered. The sputter particles emitted from each of the targets 3 ₁ to 3 ₄ adhere to and deposit on the surface of the substrate W that faces each other.

During the sputtering, each of the magnetic units 4 ₁ to 4 ₄ is moved from the starting position of the left end to the returning position of the right end by the first moving means 6, and on the other hand, the second moving means 8. The holder 7 and further, the substrate W are moved toward the return position of the left end from the starting point position of the right end. As shown in Fig. 3B, when the substrate W is at an intermediate position between the left end and the right end, each of the magnetic units 4 ₁ to 4 ₄ is also at an intermediate position between the right end and the left end. When this way the two sides of the substrate (W) and each magnet unit _(41-44) is in the intermediate position, since the respective target _(31-34), the leakage magnetic field above the center of forming a target ₍₃₁ 2-3 ₄₎ and the center of the sputtering, the sputtering particles emitted from the central portion, is attached to the substrate (W) surface opposite. And, when the back coming position (left end position) of the reciprocating path of the substrate (W) as shown in (c) of Figure 3, each magnet unit _(41-44) also returns coming position of the reciprocating movement ( Right side position). At this time, since a leakage magnetic field is formed above the right side of each of the targets 3 ₁ to 3 ₄ , the right side of the targets 3 ₁ to 3 ₄ is sputtered, and the sputtered particles emitted from the right side face the substrate ( W) Attach to the surface.

Thereafter, each of the magnetic units 4 ₁ to 4 ₄ is moved from the return position of the right end to the starting point position of the left end, and on the other hand, the substrate W moves from the returning position of the left end to the starting point position of the right end. Is moved.

In this way, the moving speed is set so that the magnet units 4 ₁ to 4 ₄ and the substrate W are moved in opposite directions, and at this time, the time until reaching the position returning from the starting point of the reciprocating motion is equal. . Then, while repeating this operation, the sputter particles from the targets 3 ₁ to 3 ₄ (react with the reaction gas) adhere to and deposit on the surface of the substrate W to form a predetermined thin film.

According to the above, the magnet units _(41-44) and because it moves the substrate (W) to the opposite direction, equal to the time taken to reach the coming location back from the starting point of the reciprocating motion, the substrate (W ) Across the entire surface so as to be equally opposed to the area where the sputter particles are emitted from the targets 3 ₁ to 3 ₄ (i.e., the plasma is irradiated across the entire surface of the substrate W), and consequently, locally There is no film thickness distribution or film quality distribution which is waved very small, and the nonuniformity of film thickness distribution and film quality distribution can be suppressed effectively.

Further, as described above, by making the distance Dt between the target centers equal to the sum of the stroke S1 of the magnet unit and the stroke S2 of the substrate W, sputter particles are emitted from each target 3 ₁ to 3 ₄ . The area | region to become becomes even more evenly across the whole surface of the board | substrate W, and the nonuniformity of a film thickness distribution and a film quality distribution can be suppressed more effectively.

In order to confirm the above effects, the following experiment was performed using the sputtering apparatus SM shown in FIG. In this experiment, the targets 3 ₁ to 3 ₄ were made of ITO, and formed into a substantially rectangular shape in the same plane, and bonded to the backing plate 31. In addition, the lengths of the targets 3 ₁ to 3 ₄ on each of the support plates 41 are used as the support plates 41 of the magnetic units 4 ₁ to 4 ₄ , each having an external dimension of 130 mm × 1300 mm. The rod-shaped central magnet 42 along the direction and the peripheral magnet 43 were provided along the outer periphery of the support plate 41.

And as a board | substrate W, it uses the so-called glass substrate for 8.5th generation flat panel displays, and, as a sputter | spatter condition, the mass flow controller (A) so that the pressure in the sputter chamber 1a which is evacuated is maintained at 0.3 Pa. 21a and 21b were controlled to introduce sputter gas, argon and water vapor gas into the sputter chamber 1a, and sputtering was performed by introducing 15 kW of input power (AC voltage) to the targets 3 ₁ to 3 ₄ . . Further, the distance was set to 216 mm between the substrate (W) and the target _(31-34).

In the experiment of the invention, when the magnet units 4 ₁ to 4 ₄ and the holder 7 and further the substrate W are moved in opposite directions in the sputters and reach a position returning from the starting point of the reciprocating motion, The time until was equal. At this time, the distance Dt (= 250 mm) between the centers of the adjacent targets 3 ₁ to 3 ₄ is determined by the stroke S1 (= 84 mm) of the magnetic units 4 ₁ to 4 ₄ and the stroke S2 of the substrate W ( = 166 mm), the moving speed of the magnetic units 4 ₁ to 4 ₄ is 14.8 mm / sec, and the moving speed of the holder 7 (substrate W) is 47.88 mm / sec. It was. About the ITO thin film formed by the experiment of this invention, the reflectance with respect to the light of 300-800 nm wavelength range is measured, and the measurement result is shown to FIG. 4 (a). The measurement location was 0 mm, 100 mm, 200 mm, 300 mm, and 400 mm when the end of the left side of the substrate W (the starting point side of the reciprocating motion) was zero. The in-plane uniformity of the measured reflectance was 0.61%, and it was confirmed that the generation of waving film thickness distribution and film quality distribution can be effectively suppressed.

In Comparative Experiment 1 for the experiment of the invention, the substrate W was fixed without moving in the sputter, and the magnetic units 4 ₁ to 4 ₄ were reciprocated at a speed of 14.8 mm / sec. Similarly to the inventive experiment, the measurement result of the reflectance of the ITO thin film formed in Comparative Experiment 1 is shown in Fig. 4B. It was confirmed that the in-plane uniformity of the reflectance was as low as 1.12% and the film thickness distribution and the film quality distribution were nonuniform.

In another comparative experiment 2, so that during the sputter, sikyeotjiman move the two sides of the substrate (W) and magnet unit _(41-44), performing the synchronization between the substrates (W) and magnet unit _(41-44) It was. That is, both were moved in the same direction as well as in opposite directions. Similarly to the experiment of the present invention, the measurement result of the reflectance of the ITO thin film obtained in Comparative Experiment 2 is shown in Fig. 4C. The in-plane uniformity of the reflectance was 0.74%, and the in-plane uniformity was improved as compared with Comparative Experiment 1, but it was found that the in-plane uniformity was lower than the experiment of the invention. Also in this case, the waving film thickness distribution and the film quality distribution are generated.

As mentioned above, although the magnetron type sputtering apparatus SM of embodiment of this invention was described, this invention is not limited to the thing of the said aspect. In the above embodiment, the holder 7 is provided in the vacuum chamber 1 to reciprocate the substrate W. For example, the sputtering device SM is configured as an in-line type, and the vacuum chamber is, for example. In the case where the substrate is conveyed by using the carrier at a position facing the target of, the carrier may be reciprocated during sputtering.

In the above embodiment, a plurality of targets are installed side by side, and AC power is supplied by AC power to a pair. However, the present invention is not limited thereto, and the target is composed of one target. The present invention can be applied. When there is only one target, there is no gap between the targets as in the above embodiment. Therefore, the backing plate 31 is sputtered so as to prevent the abnormal discharge occurs, the, the magnet unit _(41-44) domain (Dm) which does not move as shown in Figure 3 (a) Although it is not necessary to provide it, when this area | region Dm exists for some reason, this invention can be applied suitably.

In addition, the present invention can also be applied to the case where DC power is supplied from a DC power supply. The present invention can also be applied to a circular target in which the magnet unit rotates around the center of the target as the center of rotation.

SM: Sputtering Device 1a: Sputtering Room
3 ₁ to 3 ₄ : Target 4 ₁ to 4 ₄ : Magnet unit
5: floating shielding material 6: moving means
E: AC power supply M1, M2: leakage magnetic field
W: substrate

Claims (2)

Sputtering which opposes a substrate in a vacuum chamber in which a target is installed, introduces a sputter gas into the vacuum chamber, injects electric power into the target, forms a plasma in the vacuum chamber, sputters the target, and forms a film on the opposite surface of the substrate. In the method,
On the opposite side of the target substrate to the upper side, a plurality of magnet units are arranged side by side at a predetermined interval in the X direction, which is one direction of the target, from below the target, and each magnet unit tunnels above the target. To form a leaky magnetic field,
During sputtering, each magnet unit is synchronously reciprocated relative to the target with a predetermined stroke in the X direction while synchronizing, and the substrate is reciprocated relative to the target with a predetermined stroke in the X direction,
A sputtering method comprising moving the respective magnetic units and the substrate in opposite directions and equalizing the time until the respective magnetic units and the substrate reach a position returning from the starting point of the reciprocating motion. The method according to claim 1,
Wherein the target is configured by arranging a plurality of target materials of the same shape side by side at equal intervals in the X direction, the magnet unit is provided in correspondence with each target material, respectively,
A sputtering method, wherein the distance between the centers of adjacent targets is equal to the sum of the stroke of the magnet unit and the stroke of the substrate.

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