JP2017508892A - Sputtering system and sputtering method using direction-dependent scanning speed or scanning power - Google Patents

Abstract

The sputtering system has a processing chamber with an inlet port and an outlet port, and a sputtering target disposed on the wall of the processing chamber. A movable magnet device is disposed behind the sputtering target and reciprocates and slides behind the target. The conveyor continuously conveys the substrate through the sputtering target at a constant speed so that at any given time, several substrates are facing the target between the tip and end. In some embodiments, the movable magnet device slides at a speed that is at least several times faster than the constant speed of the conveyor. The turning zone is defined behind the tip and end of the target and decelerates when the magnet device enters the turning zone and accelerates when the sliding direction is reversed within the turning zone. In some embodiments, the magnet power and / or magnet speed is varied depending on the direction of magnet travel. [Selection] Figure 6

Description

(Related application)
This application is filed on Nov. 2, 2012, claiming priority based on US Provisional Application No. 61 / 556,154, filed Nov. 4, 2011, “Line Scanning Spacling System and Lines”. This is a continuation-in-part of US patent application 13 / 667,976 entitled “Scanning Spacling Method”, the entire disclosure of which is incorporated herein by reference.

(Technical field)
The present application relates to a sputtering system, for example, a sputtering system used to deposit a thin film on a substrate during the fabrication of integrated circuits, solar cells, flat panel displays, and the like.

  Sputtering systems are well known in the art. An example of a sputtering system having a linear scanning magnetron is disclosed in US Pat. No. 5,873,989. Thus, a magnetron sputtering source for depositing material on a substrate includes a target for sputtering the material, a magnet assembly provided close to the target for confining plasma on the target surface, and scanning the magnet assembly relative to the target. A drive assembly. The sputtering process requires the generation of a gas plasma and then acceleration of ions from this plasma into the target. The source material of the target is eroded by the ions reached via energy transfer and is ejected in the form of neutral particles of individual atoms and either atoms or molecular clusters. Since these neutral particles have been ejected, they move in a straight line to impact and coat the substrate surface as desired.

  One problem to be solved in such a system is the uniformity of the film formed on the substrate. Another problem to be solved in such a system is target utilization. Specifically, since the magnet of the linear magnetron performs scanning in a reciprocating manner, excessive sputtering occurs at both ends of the target, and two deep grooves are generated along the scanning direction, that is, in parallel. As a result, the target must be replaced even though the majority of the target surface is still usable. Various methods to counter this phenomenon are disclosed in the '989 patent.

  However, another target utilization problem that has not been addressed so far is erosion that occurs at the end of a scan cycle. That is, when the magnet reaches the end of the target, the scanning direction is reversed. In order to achieve film uniformity, the '989 patent proposes reducing the scanning speed towards either end of the target. However, this leads to increased sputtering of the target and excessive erosion at both ends of the target in the direction perpendicular to the scanning direction.

  Accordingly, there is a need in the art for sputtering systems that enable uniform film formation and improved target utilization.

  The following summary is included to provide a basic understanding of some aspects and features of the invention. This summary is not an extensive overview of the invention and is not intended to identify key or critical elements of the invention or to limit the scope of the invention. Its sole purpose is to present some concepts of the invention in a simplified form as a prelude to the more detailed description that is presented later.

  Disclosed herein is a sputtering system and method that enhances the uniformity of a film formed on a substrate and enables high throughput. One embodiment provides a system in which a substrate operates continuously in front of a sputtering target. The magnetron is scanned linearly back and forth at a speed that is at least several times faster than the movement of the substrate. The magnetron is repeatedly scanned in the direction of travel of the substrate and then in the opposite direction. During most of the movement, the magnetron is moved at a constant speed. However, when approaching the end of the movement, it decelerates. After that, when the movement in the opposite direction starts, it accelerates until reaching a certain speed. The deceleration / acceleration in one embodiment is 0.5 g and in another embodiment is 1 g. This improves the utilization rate of the target. According to another embodiment, the turning point of the magnetron is changed in subsequent scans so that the inversion band is defined. This helps improve target utilization.

  The sputtering system has a processing chamber with an inlet port and an outlet port, and a sputtering target disposed on the wall of the processing chamber. The moving magnet device is disposed behind the sputtering target and slides back and forth behind the target. The conveyor passes the sputtering target continuously through the sputtering target at a constant speed so that at any given time, several substrates are facing the target between the tip and end. The moving magnet device slides at a speed that is at least several times faster than the constant speed of the conveyor. The turning zone is defined behind the tip and end of the target and decelerates when the magnet device enters the turning zone and accelerates when the sliding direction is reversed within the turning zone.

  In accordance with some embodiments of the present invention, a system for sputtering material from a target onto a substrate includes a carrier capable of transporting the substrate in a downstream direction and a first processing chamber for passing the substrate in the downstream direction. And the above processing chamber. The first processing chamber operates to transversely scan the sputtering target with the sputtering target in the downstream direction at a downstream scanning speed, and transversely scan the sputtering target in an upstream direction opposite to the downstream direction at an upstream scanning speed that is slower than the downstream scanning speed. Possible magnets.

  In accordance with some embodiments of the present invention, a processing chamber scans a sputtering target with a sputtering target in a downstream direction at a downstream scanning speed and an upstream scanning speed that is slower than the downstream scanning speed in an upstream direction opposite to the downstream direction. And a magnet operable to traverse the sputtering target.

  In accordance with some embodiments of the present invention, a method of sputtering includes passing a substrate through a sputtering target at a downstream speed and transporting a substrate, and a magnet traverses the sputtering target in a downstream direction at a downstream scanning speed, And inducing sputtering of the target material onto the substrate by traversing the sputtering target in an upstream direction opposite to the downstream direction at an upstream scanning speed that is slower than the downstream scanning speed.

  In accordance with some embodiments of the present invention, a system for sputtering material from a target onto a substrate includes a carrier capable of transporting the substrate in a downstream direction and a first processing chamber for passing the substrate in the downstream direction. And the above processing chamber. The first processing chamber traverses the sputtering target with the sputtering target at a downstream scanning power level in the downstream direction, and the sputtering target at an upstream scanning power level greater than the downstream scanning power level in the upstream direction opposite to the downstream direction. And a magnet operable to transverse scan.

  In accordance with some embodiments of the present invention, the processing chamber scans the sputtering target with the sputtering target at a downstream scanning power level in the downstream direction and is greater than the downstream scanning power level in the upstream direction opposite to the downstream direction. And a magnet operable to scan across the sputtering target at a power level of upstream scanning.

  In accordance with some embodiments of the present invention, a method of sputtering includes passing a substrate through a sputtering target at a downstream speed and transporting a substrate, and a magnet traverses the sputtering target in a downstream direction at a power level of downstream scanning, And inducing sputtering of the target material over the substrate by traversing the sputtering target in an upstream direction opposite the downstream direction at a power level of upstream scanning that is greater than the power level of downstream scanning.

  In accordance with a further aspect of the invention, a sputtering apparatus provided for a deposition chamber includes a target having a front surface and a back surface, a sputtering material provided on the front surface, and a reciprocating scan in proximity to the back surface of the target. A movable magnet mechanism having a magnet configured to do so, and a counterweight configured to reciprocate in the opposite direction at the same speed as the magnet. Having a counterweight that moves in the opposite direction at the same speed as the magnet reduces vibrations and loads in the system, and the magnet can scan at a faster speed and is accelerated and decelerated at a faster pace. obtain. The movable magnet mechanism includes a power element that is driven to move the target and counterweight back and forth, and the magnet and counterweight are mechanically coupled to the power element. The power element may be a variable tension element including, for example, a belt, a timing belt, and a chain. A motor is coupled to the power element to drive the power element, and a controller provides a signal to drive the motor.

  In accordance with another aspect, a method for operating a sputtering system and a controller for operating the sputtering system are provided. The controller can be operated to repeatedly scan the magnetic poles, which repeatedly scans the upstream distance X and then inverts and scans the downstream distance Y to the end of the target. In this case, the distance X in the downstream direction is repeatedly scanned and then reversed and the distance Y in the upstream direction is scanned, where X is longer than Y and X is shorter than the target length. In one embodiment, at least one of X and Y is constant, or the distance | X |-| Y | is kept constant.

  The above aspects and features can be “mixed and matched” in any designed system, thereby obtaining the desired benefits. For maximum benefit, a particular system may include all the aspects and features described above, depending on the particular situation and particular application, while other systems apply only one or two features. May be.

  The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the detailed description, serve to explain and depict the principles of the invention. The drawings are intended to illustrate the main features of the exemplary embodiments in a diagrammatic manner. In addition, the drawings are not intended to show all features of actual embodiments or the relative sizes of the illustrated elements. Therefore, the drawings are not to scale.

1 illustrates a portion of a system for processing a substrate using a sputtering magnetron, according to one embodiment. Fig. 2 shows a section along the line AA in Fig. 1; Fig. 3 shows a section along the line BB in Fig. 1; Fig. 4 illustrates another embodiment where the substrate is supported on a conveyor that operates continuously at a constant speed. Fig. 4 shows another embodiment in which counterweight is used to balance the movement of the scanning pole. An example of a system configuration using a sputtering chamber as shown in FIGS. 4A and 4B is shown. Fig. 4 illustrates an embodiment of a movable pole that can be used in any of the disclosed embodiments. It is a graph of the film-forming uniformity at the time of using a fixed wafer conveyance speed and a different magnet scanning speed. It is a graph of the film-forming uniformity at the time of using a fixed wafer conveyance speed and a different magnet scanning speed. It is a graph of the film-forming uniformity at the time of using a fixed wafer conveyance speed and a different magnet scanning speed. It is a graph of the film-forming uniformity at the time of using a fixed wafer conveyance speed and a different magnet scanning speed. It is a graph which shows that a uniformity falls, when a magnet scanning speed rises. It is another graph which shows the special transition of the film-forming uniformity with respect to the magnet scanning speed faster than a scanning speed. It is an enlarged view of the part enclosed by the circle | round | yen of FIG. 8B.

  Hereinafter, embodiments of the sputtering system of the present invention will be described with reference to the drawings. Different embodiments may be used to process different substrates to achieve different benefits such as throughput, film uniformity, target utilization, and the like. Depending on the outcome sought, the different features disclosed herein may be utilized in part or in full, either alone or in combination to balance the benefits with requirements and constraints. As such, reference to various embodiments highlights certain benefits, but they are not limited to the disclosed embodiments.

  FIG. 1 illustrates a portion of a system for processing a substrate using a sputtering magnetron, according to one embodiment. In FIG. 1, three chambers 100, 105, 110 are shown, but the three dots at each end indicate that any number of chambers may be used. Also, although three specific chambers are shown here, it is not necessary to employ the chamber configuration shown here. Other chamber configurations may be used, and other types of chambers may be provided between the illustrated chambers. For example, the first chamber 100 may be a load lock, the second chamber 105 may be a sputtering chamber, and the third chamber 110 may be another load lock.

  For the sake of explanation, in the example of FIG. 1, the three chambers 100, 105, and 110 are assumed to be sputtering chambers evacuated by respective vacuum pumps 102, 104, and 106. Each processing chamber has a transfer section 122, 124 and 126 and a processing section 132, 134 and 136. The substrate 150 is placed on the substrate carrier 120. In this embodiment, the substrate 150 is held at the periphery (ie, without touching any of its surfaces) so that both surfaces are formed by the sputtering target material on both sides of the substrate. The carrier 120 has a set of wheels 121 that rest on a track (not shown in FIG. 1). In one embodiment, the wheels are magnetized to provide better traction and stability. The carrier 120 is placed on a rail provided in the transfer section so as to place the substrate in the processing section. In one embodiment, the carrier 120 is externally attached to the carrier 120 using a linear motor device (not shown in FIG. 1). Supply driving force. If the three chambers 100, 105 and 110 are sputtering chambers, the carrier 120 enters and exits the system via a load lock device.

  FIG. 2 shows a section along the line AA in FIG. For simplicity, the substrate 250 is shown in the absence of a carrier in FIG. 2, but the substrate 250 remains on the carrier 120 throughout the process performed in the system of FIG. It should be understood that the substrate carrier is continuously transferred from chamber to chamber as indicated by. In this exemplary embodiment, in each chamber 200, 205 and 210, the substrate 250 is processed on both sides. Also shown in FIG. 2 are isolation valves 202, 206 that isolate each chamber during fabrication, but in one embodiment, the isolation valve is replaced with a simple gate for the substrate to move continuously. It can also be done or removed.

  Each chamber includes movable magnetrons 242, 244, 246 mounted on linear trajectories 242 ′, 244 ′, 246 ′ so as to scan the plasma over the surface of target 262, as indicated by the double arrows. . The magnet is scanned back and forth continuously so that the substrate is transported downstream on the carrier in the chamber. As shown with respect to magnet 242, when the magnet reaches tip 243 of target 262, it reverses and moves toward end 247 of target 262. When the end 247 is reached, it is reversed again and scanned towards the tip 243. This scanning process is continuously repeated. Note that in this particular example, the downstream direction is aligned in parallel from the tip 243 to the end 247 of the target 262. Also, as described herein, the tip may be referred to as an upstream position or upstream region, but the end may be referred to as a downstream position or downstream region. In this respect, upstream and downstream are defined with reference to the direction of travel of the substrate, which reaches the upstream tip 243 before reaching the downstream end 247 traveling through the target 262.

  FIG. 3 shows a section along the line BB in FIG. The substrate 350 is shown mounted on the carrier 320. The carrier 320 has wheels 321 mounted on the track 324. The wheel 321 may be magnetic, in which case the track 324 may be made of a paramagnetic material. In this embodiment, the carrier is moved by a linear motor 326, although other driving forces and / or devices may be used. The chamber is evacuated and a precursor gas, such as argon, is supplied into the chamber to maintain the plasma. The plasma is ignited and maintained by applying RF bias energy to the movable magnetron 344 located behind the target 364.

  In another embodiment shown in FIG. 4A, the substrate 450 is supported on a conveyor 440 that operates continuously for “passing” processing, with a configuration for passing through the gates 402 and 406. This configuration is particularly beneficial when it is necessary to sputter only on one side of the substrate, such as when making solar cells. For example, several substrates can be placed side by side and some can be processed simultaneously. The balloon diagram of FIG. 4A shows three substrates arranged side by side, ie, along the direction of vertical motion as indicated by the arrows. It can be said that the substrates are arranged in a plurality of rows and a plurality of columns. The dots in the balloon diagram of FIG. 4A indicate that the substrate supply may be “continuous” in the row direction, since the number of substrates is always replenished on the conveyor. Thus, the substrates are arranged in a “continuous” supply direction or row direction and n rows, where n can be any integer, n in FIG. Also, in such an embodiment, when the target 464 is long relative to the dimensions of the substrate, the belt continuously moves the substrate under the target 464, so that multiple substrates are processed simultaneously in the vertical and horizontal directions. be able to. For example, when using three rows, that is, three side-by-side wafers, the dimensions of the target are designed so that four rows and three rows of substrates can be processed, whereby 12 substrates can be processed simultaneously. As described above, the magnetron 444 reciprocates linearly between the front end and the end of the target in a direction parallel to the traveling direction of the substrate, as indicated by a double arrow. Plasma 403 follows the progression of magnetron 444 on the opposite side of target 464, thereby sputtering material from target 464 onto substrate 450.

  FIG. 4B shows another embodiment having a scan pole 442 and a counterweight 446. Specifically, the scanning magnetic pole 442 is linearly reciprocated as indicated by a double arrow. At either end the scan must reverse direction. This inversion can cause vibrations in the system and can limit deceleration and acceleration. To reduce this effect, the counterweight 446 is provided as a counter balance and is scanned in the opposite direction to the magnetic pole to cancel the magnetic pole movement. This reduces vibrations in the system and enables fast deceleration and acceleration of the magnetic poles.

  In the particular example of FIG. 4B, the magnetic pole 442 and the counterweight 446 are slidably coupled to the linear track assembly 445 so that the magnetic pole 442 and the counterweight 446 slide freely on the linear track assembly 445. Although the linear track assembly is seen as a single track from the perspective of FIG. 4B, several tracks can be arranged to support the magnetic pole 442 and the counterweight 446 to move freely and linearly back and forth. The magnetic pole 442 is attached to one side of the power element 448, while the counterweight 446 is attached to the other side of the power element 448. The power elements 448 may be conveyors such as wheels 441 and chains rotating above the wheels 443, belts, toothed (timing) belts, and the like. One of the wheels, for example, the wheel 443 is driven by a motor 449 through a coupling mechanism 447, for example, a toothed belt. The motor 449 is controlled by the controller 480, which sends a signal to the motor 449 to rotate the wheel 443 in a reciprocating manner, so that the conveyor 448 slides the magnetic pole 442 back and forth in the track 445 while counterweighting. Slide 446 in the opposite direction. That is, the counterweight is at the same speed as the magnet but moves in the opposite direction to the magnet. In general, this arrangement greatly reduces the load on the motor and system. This arrangement also reduces vibration and enables high speed, high acceleration and high deceleration.

  FIG. 5 shows an example of a system as shown in FIG. 4A or 4B. The atmospheric conveyor 500 continuously moves the substrate into the system, after which the substrate is transferred onto the conveyor in the system to traverse the low vacuum load lock 505, the high vacuum load lock 510 and, if necessary, a transfer chamber. Cross 515. The substrate is then processed by a subsequent chamber 520, shown one or more, here two, while moving continuously on the conveyor. The substrate then proceeds on the conveyor in the order of any transfer chamber 525, high vacuum load lock 530, low vacuum load lock 535, and atmospheric conveyor 540 and exits the system.

  FIG. 6 shows an embodiment of a movable magnetron that can be used in any of the previous embodiments. In FIG. 6, the substrate 650 is moved by the conveyor 640 at a constant speed. A target assembly 664 is disposed on the substrate, and the movable magnetron 644 oscillates back and forth linearly behind the target assembly as indicated by the double arrow. The plasma 622 follows the magnetron and causes sputtering from different areas of the target. In this embodiment, the speed of the magnetron is constant during normal movement and is at least several times faster than the speed of the substrate. This rate is calculated so that the substrate is sputtered several times by a movable magnetron while traversing the sputtering chamber. For example, the speed of the magnetron can be 5 to 10 times faster than the speed of the substrate, thereby depositing multiple layers on the substrate before the conveyor moves the substrate through the entire length of the target. Thus, the magnet is reciprocated several times behind the target.

  As shown in FIG. 6, in this embodiment, each substrate has a length Ls defined in the traveling direction of the conveyor belt. Similarly, the length of the target defined in the traveling direction of the conveyor parallel to the traveling direction of the magnet is Lt. In the present embodiment, the target length Lt is several times longer than the substrate length Ls. For example, the target length can be four times longer than the pitch defined as the length of one substrate plus the length of the separation distance S between the two substrates on the conveyor. That is, the pitch P = (Ls + S).

  The problem with the linear movement of the magnetron behind the target is that when it reaches the tip and end of the target, it stops and starts moving in the opposite direction. As a result, the end of the target is significantly eroded from the main surface of the target. If the erosion at the end of the target exceeds a predetermined amount, the target needs to be replaced even though the center of the target is still usable. Various embodiments as described below are used to address this problem.

  According to one embodiment, offsets E and F at the tip and end of the target, respectively, are specified. When the magnetron reaches the offset, it decelerates at a prescribed speed such as 0.5 g or 1 g. At the end of the offset, the magnetron reverses and accelerates at the specified speed. This takes place at both ends of the magnetron movement, ie at the tip and end of the target.

According to another embodiment, turning zones are defined, for example, zone E and zone F are designated at the tip and end of the target, respectively. When the magnetron reaches one of the turning zones, the direction of travel is reversed at a point in the turning zone. However, as time passes, the point at which the magnetron reverses direction within the turning zone shifts. This is illustrated by the balloon diagram of FIG. As illustrated, at time _{t 1,} the inversion point is represented by _{F 1.} At time t ₂ , the inversion point is denoted F ₂ , closer to the end of the target than point F ₁ , but still within the band denoted F. At time _{t 3,} reversal point _{F 3} is further an end side of the target, at time _{t n, F n} is away from the end of the target. However, all points F _i are in band F. The same process is performed in the opposite zone E, that is, the tip of the target.

  The point for reversing the scanning direction can be selected in various ways. For example, a random selection can be made every scan, every two scans, or after x scans. On the contrary, for each scan, the minute point of distance Y is moved in one direction until the end of the band is reached, and then the program is executed to start moving the distance Y toward the opposite end of the point You can also. On the other hand, after moving in one direction by Z, in the next step, moving in the opposite direction by −w (| w | <| Z |) can specify movement to generate an interlace pattern.

  In the embodiments described herein, the magnetron is scanned at a constant speed throughout the process, since it has been found that changing the scan speed adversely affects the film uniformity of the substrate. is there. In particular, in a configuration where the substrate moves continuously in front of the target, decelerating or accelerating the magnet array over the processing region is not a good idea for controlling film thickness uniformity.

  In the disclosed embodiment, moving a large number of substrates on a conveyor can be viewed as a continuous (very long) substrate that is moved at a constant speed. The scanning speed must be selected to provide good uniformity for a substrate moving at a constant speed. In these embodiments, the start position, stop position, acceleration and deceleration are used for special applications in order to control target utilization. This has the effect of expanding the range of deep grooves that occur at both ends when reversing the motion.

  The polar design is used to reduce deep grooves above and below the plasma trajectory. The scan is done at a fairly high speed and a thicker target can be used or a larger power can be utilized for the target to spread the power over the entire surface of the substrate. Since each substrate passes through a plurality of targets passing through the plasma, the start position and the stop position can be different for each pass, and the influence of changes in the scan length for each pass is not seen in the film uniformity. . That is, although the embodiment of FIG. 6 has been described such that the turning zone is designed outside the processing region, this is not necessary when the substrate moves continuously as described herein. Absent. The turning zone can exist in the processing region.

  For example, according to one embodiment, the system is used to make solar cells at a rate of 2400 substrates per hour. The conveyor continuously moves the substrate at a pace of about 35 mm / sec. The magnetron is scanned at a pace of at least 250 mm / sec, i.e. more than 7 times the speed of substrate transport. The target and magnetron are designed so that the moving distance in one direction of the magnetron scanning is about 260 mm. This gives film uniformity exceeding 97%. The acceleration / deceleration may be set to 0.5 g at a distance of about 6.4 mm or 1 g at about half the distance. As shown in FIG. 6, various calculations may be performed by one or more controllers 680 to control magnetron scan speed, magnetron power, substrate travel speed (eg, conveyor speed), and the like.

  7A-7D are graphs of film formation uniformity when using a constant wafer transport speed and different magnet scanning speeds. FIG. 7A is a graph of uniformity versus magnet scan speed of about 5% of wafer transport speed. For example, the magnet was scanned at 1.75 mm / s for a wafer transfer speed of 35 mm / s. The film uniformity obtained was 90%, which is insufficient for the production of devices such as solar cells. As shown in FIG. 7B, uniformity is reduced to 86% when the magnet scanning speed is increased to 7.5% of the wafer speed. Furthermore, when the speed increases to 10%, the uniformity decreases to 82%, and when the speed increases to 12.5%, the uniformity further decreases to 78%. Therefore, it appears that the film uniformity is considerably reduced by increasing the magnet scanning speed, which suggests that the magnet scanning speed should be a low ratio with respect to the wafer conveyance speed. This conclusion is further supported by the graph shown in FIG. 8A where the uniformity decreases as the magnet scanning speed increases.

However, the graph of FIG. 8A also shows that the maximum achievable uniformity can be on the order of about 90%. As noted above, such uniformity is unacceptable in many processes. Therefore, further investigation was performed, and as a result, the graph of FIG. 8B was obtained. The graph of FIG. 8B shows a unique transition of film formation uniformity with respect to the magnet scanning speed. In fact, as the magnet scanning speed increases, the film uniformity decreases. However, as the magnet scan speed further increases at a particular point, the uniformity begins to improve suddenly, and a peak of uniformity of about 98% is achieved at around the magnet scan speed, which is three times the wafer transport speed. Thereafter, a drop in uniformity is observed for a short time, but when the magnet scanning speed becomes about 5 times or more the wafer conveyance speed, the uniformity is recovered and maintained at a high level in the graph of FIG. 8C. Indicated. As shown in FIG. 8C, which is an enlarged view of a portion surrounded by a circle in FIG. 8B, the uniformity is maintained at 97% or more at a speed exceeding 5 times the wafer conveyance speed, and a speed about 10 times the conveyance speed. In this case, the uniformity is maintained at 98% or more. Higher speeds are not recommended from a mechanical load and mechanical design perspective, and higher speeds do not appear to improve the uniformity much. Thus, the cost of complex designs and the maintenance costs that can be high may not guarantee that the scanning speed will exceed 10 times the wafer transport speed.

In some embodiments, the scanning speed may vary depending on the direction of magnet travel. For example, when the magnet scans the target in the downstream direction (ie, the same direction as the substrate motion), the magnet can move at a constant speed. This speed is faster than the scanning speed of the magnet when the magnet scans the target in the upstream direction (ie, the direction opposite to the substrate motion). Such a speed change can provide better control of the deposition rate and improves deposition uniformity. In some embodiments, such speed changes are used to balance the length of time that the magnet spends passing through the substrate downstream and upstream. That is, the magnet scanning speed can be selected so that the “relative” speed, ie the speed of travel of the magnet relative to the target, is the same in both travel directions. For example, the substrate velocity when the relative velocity of the S _S and the magnet are S _t, whereas when the magnet travels in the downstream direction should be scanned at a speed S _t + S _S, the magnet travels in the upstream direction The time should be scanned at the speed S _t -S _S.

  Further, in some embodiments, the magnetron power may vary depending on the direction of magnet travel. For example, the power applied when the magnet scans the target in the downstream direction is less or greater than the power applied when the magnet scans the target in the upstream direction. Such power changes can provide better control of the deposition pace and improve deposition uniformity. In some embodiments, such power changes can be used to balance the amount of power applied to pass the magnet downstream and upstream through the substrate.

In some embodiments, changes in both speed and power can be used in combination, depending on the direction of magnet scanning. That is, as in the above example, in order to generate a constant relative scanning speed, the scanning speed when the magnet travels downstream is faster than the scanning speed when the magnet travels upstream. That is, the time that the magnet spends traveling over the predetermined target area in the downstream direction is less than the time it spends traveling over the predetermined target area in the upstream direction. Thus, according to one embodiment of the present invention, the total amount of power supplied to the target during all downstream scans is equal to the total amount of power supplied to the target during all upstream scans. The magnetron power is changed while traveling downstream and / or upstream. Therefore, if the total power supplied during the one scanning direction is P _d, and a scanning direction time taken to scan to (either direction) is t _s, it is applied to the magnetron in each direction power is calculated as W = Pd / _{t s,} where, _{t s} is to exert the scanning speed _{S t} + _{S S} or _{S t} -S _S responsive to the traveling direction to the length _{L t} of the target Calculated.

  On the other hand, for example, the upstream magnet speed and the downstream magnet speed are constant, or the time during which the substrate is exposed to magnet scanning during upstream scanning is greater than the time during which the substrate is exposed to magnet scanning during downstream scanning. In such cases, it may be beneficial to increase the power during the upstream scan compared to the power level during the downstream scan. That is, if the substrate is shorter than the time exposed to sputtering from the target during upstream travel of the magnet, the sputtering power is increased during upstream travel to deposit more material per unit time on the substrate Should be allowed. The power difference can be calculated so that the amount of material deposited per unit time on the substrate is the same when the magnet is scanned in either the upstream or downstream direction. That is, the material sputtered from the target per unit time varies between upstream and downstream travel of the magnet, but upstream scanning of the magnet so that the amount of material deposited on the substrate per unit time is the same. And the power during downstream scanning can be adjusted. For example, the amount of material sputtered from the target per unit time during the upstream travel of the magnet is greater than the amount of material sputtered from the target per unit time during the downstream scan of the magnet, but the upstream scan and downstream of the magnet During the scan, the sputtering power may be increased during the upstream travel of the magnet so that the amount of material deposited on the substrate per unit time is the same.

  Using the above disclosure, a processing chamber scans a sputtering target configured to pass a substrate in a downstream direction and a downstream scanning power level in a downstream direction, and in an upstream direction opposite to the downstream direction. And a magnet operable to traverse the sputtering target at an upstream scan power level that is less than or greater than a downstream scan power level. The magnet may be reversed at the turning zone at the end in the direction of travel of the target. Also, subsequent inversions in each turning zone occur at different positions. Different locations may be selected at random. The length of the target may be greater than the length of the substrate. The plurality of substrates may be arranged at a predetermined pitch, pass through the processing chamber, and the magnet may have a length at least four times the pitch.

  The reversal of scanning is not limited to the turning band, and can be extended to the entire length of scanning. For example, the magnet may scan at a distance of Xmm and then invert and travel at a distance of -Ymm (| X |> | -Y |). Further, the progress of the magnet is reversed, scanning is performed at a distance of another Xmm, and then reversed at a distance of another -Ymm. Thus, the magnet advances at Xmm and retracts at -Ymm, but since the absolute length of X is longer than the absolute length of Y, scanning is performed over the entire length of the target. Thereafter, when the magnet reaches the end of the target, the magnet travels at a distance of -Xmm, ie, Xmm in the direction opposite to the previous travel direction. The magnet reverses and travels at a distance of Ymm. This scan is repeated so that the magnet scan reversal is not limited to the end but extends over a wide range of the target. In some embodiments, X and Y are constant, but in other embodiments, X and Y can be varied depending on, for example, the condition of the target.

  In some embodiments, the target scan distance may be a total of about 240 mm. The pole starts at the initial position and scans a portion of the total distance, eg, 100 mm, for each scan before performing the first inversion. Thereafter, the pole does not return completely to the initial position, but returns to a position offset from the initial position. For a total return distance of 60 mm, the offset may be 40 mm in one example. Also, in this example, this pattern is repeated 6 times to cover a total of 240 mm. As a result, the scan inversion point extends across the entire surface of the target and is not constrained by the inversion band. In some embodiments, high acceleration / deceleration (about 4-5 g, g = 9.80665 meters per second), a scanning speed of about 1000 mm / sec is performed, and the length of a single scan is 240 mm On the other hand, a net speed (NetSpeed) corresponding to a scanning speed of 210 mm / sec is achieved. Of course, these numbers are used as examples and may be varied depending on the particular application. This attempt allows the start / stop zone to move downstream or upstream, thus allowing the start / stop zone to extend over a large area, increasing target utilization and maintaining good film thickness uniformity on the substrate. To do. In some embodiments, programmed to set upstream scan speed, downstream scan speed, start-stop acceleration / deceleration, upstream power, downstream power, power during acceleration, and power during deceleration. The results of this approach were realized using a controller. Each of these parameters may be individually controlled and varied by the controller to obtain the desired effect.

  Also, in some embodiments, the upstream and downstream start and stop positions are equidistant for each subsequent scan, which is shorter than the entire scan distance, so the start / stop positions move with each subsequent pass. For example, in FIG. 6, the distance between each point F and E is kept constant at F at all points. Also, in the embodiment of FIG. 6, bands F and E are shown to be limited to the end of the target. However, as described in the previous example, the turning point need not be limited to the end of the target, but rather may extend over the entire length of the substrate.

  The various features described herein may have one or more technical features, depending on the needs of a particular application. In one embodiment, the upstream scan speed and the downstream scan speed may be the same size or different sizes. In one embodiment, the acceleration and deceleration in the upstream and downstream start and stop bands may be the same or different. In one embodiment, the power applied to the upstream and downstream magnetrons may be the same or different. In one embodiment, the upstream and downstream start positions and stop positions may be the same or different. In one embodiment, the upstream and downstream start and stop positions are equidistant for each subsequent scan, which is shorter than the entire scan distance, so the start / stop position moves with each subsequent pass.

  The sputtering method also includes a step of transporting the substrate through the sputtering target in the downstream direction, and a magnet is scanned across the sputtering target in the downstream direction at the power level of the downstream scanning in the upstream direction opposite to the downstream direction. Directing sputtering of the target material onto the substrate by scanning the magnet across the sputtering target at an upstream scan power level greater than the downstream scan power level. The direction of the magnet may be reversed in the turning zone at the end in the direction of travel of the target. Also, subsequent inversions in each turning zone occur at different positions. Different locations may be selected randomly.

  As described above, a system for depositing material from a target onto a plurality of substrates includes and is provided with a conveyor capable of transporting the plurality of substrates in the downstream direction and a processing chamber through which the substrates are passed in the downstream direction. The The processing chamber has a target parallel to the downstream direction and having a length longer than the length combined with the n substrates, and a magnet capable of reciprocating scanning across the target. In some embodiments, a downstream scanning power level is applied to the target while scanning in the downstream direction, an upstream scanning power level is applied to the target while scanning in the upstream direction opposite to the downstream direction, and the upstream scanning power is It may be different from the downstream scanning power level. In another embodiment, the counterweight is configured to scan in the opposite direction at the same speed as the magnet. In yet another embodiment, the conveyor transports n rows of substrates, where n is an integer. In a further embodiment, the magnet reverses the scan direction at different locations along the length of the target, and the reverse direction moves along the length of the target. In a further embodiment, the downstream scan speed and the upstream scan speed are set to maintain a constant speed in either the downstream or upstream scan direction between the magnet and the substrate.

  It should be understood that the process steps and techniques described herein are not inherently related to any particular apparatus, but may be implemented by any suitable combination of members. Furthermore, various types of general-purpose devices may be used in accordance with the knowledge described herein. The invention has been described in terms of specific examples, which are intended in all respects to be illustrative rather than restrictive. Those skilled in the art will appreciate that many different combinations are suitable for the practice of the present invention.

  Furthermore, other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention described herein. Various aspects and / or components of the described embodiments may be used alone or in combination. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

Claims (20)

A system for depositing material from a target onto a substrate,
A carrier capable of transporting the substrate in the downstream direction;
One or more processing chambers including a deposition chamber through which the substrate passes in a downstream direction,
The film forming chamber includes
Target,
A magnet assembly capable of magnetically traversing the target in a downstream direction at a downstream scanning speed and transversely scanning the target in an upstream direction opposite to the downstream direction at an upstream scanning speed;
A controller capable of controlling the scanning speed according to the scanning direction,
The system, wherein the scanning speed is varied according to the upstream or downstream direction of travel of the magnet assembly.   The system of claim 1, wherein the upstream scan rate is slower than the downstream scan rate.   The system of claim 1, wherein the downstream scan rate is at least five times faster than a rate at which the substrate passes through the first processing chamber.   The system of claim 1, wherein the downstream scanning speed and the upstream scanning speed are set to maintain a constant speed of the magnetic pole relative to the substrate in either the downstream or upstream scanning direction.   The system of claim 1, wherein the controller applies different power to the target during a downstream scan of the magnetic pole and during an upstream scan of the magnetic pole.   6. The system of claim 5, wherein the total power supplied to the target during all the downstream scans is equal to the total power supplied to the target during all the upstream scans.   The system of claim 1, wherein the magnetic pole reverses direction at a turning zone at an end of the target traveling direction, and subsequent inversions at each turning zone occur at different locations.   The system of claim 7, wherein the different locations are randomly selected. The controller is operable to repeatedly scan the magnetic poles;
The operation is
Scan the distance X in the upstream direction repeatedly, then invert and scan the distance Y in the downstream direction,
When the end of the target is reached, the downstream distance X is repeatedly scanned, and then reversed to scan the upstream distance Y.
The system of claim 1, wherein X is longer than Y and X is shorter than the length of the target.   The system of claim 9, wherein at least one of X and Y is constant.   The system according to claim 9, wherein the distance | X | − | Y | is kept constant.   The system of claim 1, wherein a length of the target is greater than a length of the substrate. A plurality of substrates are arranged at a predetermined pitch, the plurality of substrates pass through the processing chamber,
The system of claim 1, wherein the length of the target is at least four times the length of the pitch.   The system according to claim 1, wherein the deposition chamber further includes a counterweight capable of scanning in a direction opposite to the magnetic pole. The magnet assembly includes a linear track assembly, a counterweight movably coupled to the linear track assembly, a conveyor, and a motor coupled to drive the conveyor in accordance with a signal from the controller. And comprising
The magnetic pole is coupled to the linear track assembly movably in the linear track assembly;
The system of claim 1, wherein one side of the conveyor is coupled to the magnetic pole, while the other side of the conveyor is coupled to the counterweight. Transporting the substrate through the target at a downstream speed;
Target material on the substrate by reciprocally scanning the magnet across the target at different speeds depending on the upstream and downstream directions of scanning of the magnet in opposite downstream and upstream directions Inducing film formation.   The method of claim 16, wherein the upstream scan rate is slower than the downstream scan rate.   The method of claim 16, wherein the downstream scan rate is at least five times faster than the upstream scan rate.   The method of claim 16, further comprising the step of reversing the scan direction at a turning zone at an end of the target in the direction of travel, and subsequent reversals in each turning zone occur at different locations.   The method of claim 19, wherein the different locations are randomly selected.