BRIEF DESCRIPTION OF THE DRAWINGS
These and other features and advantages will be better and more completely understood by reference to the following detailed description of exemplary illustrative embodiments in conjunction with the drawings, of which:
FIG. 1 is a simplified and partially schematic side elevation of a conventional sputtering apparatus;
FIG. 2 shows a side cross-section of a modular magnet bar structure in accordance with an example embodiment of this invention;
FIG. 3 is a partial perspective view of the modular magnetic bar structure of FIG. 2 showing a central portion of the stationary magnet bar structure which is located inside of the rotating sputtering target tube;
FIG. 4 is a partial perspective view of an end portion of the modular magnetic bar structure of FIGS. 2-3; and
FIG. 5 is a perspective view of a significant portion of the modular magnet bar structure of FIGS. 2-4.
DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION
Referring now more particularly to the accompanying drawings in which like reference numerals indicate like parts throughout the several views.
Certain example embodiments provide a modular and/or segmented magnetic bar structure for sputtering targets. The structure may include a plurality of elongated magnet bars, each magnet bar including a plurality of segments aligned linearly or in series. Such modular magnetic bars may, for example, include five segments (although any suitable number of segments may be provided per bar). Considerations taken into account as to how may segments to provide per magnet bar may include, for example, the size of the sputtering target, the degree of accuracy required with respect to the magnetic field, etc. Multiple segments may be arranged within a sputtering target to function as a single magnet bar. In general, though, more segments in the modular design will allow for more finely-tuned magnetic fields, as each segment preferably can be individually adjusted in certain example non-limiting embodiments of this invention.
Each segment of a given magnet bar may be sized the same or substantially the same in certain example embodiments; however, the invention is not so limited. Indeed, multiple different segments may be substituted in certain example embodiments to customize the magnetic field to be generated. For example, changing an end module with a different magnet row length may increase or decrease the target exploitation. Thus, providing a number of magnetic segments in accordance with pre-determined configurations may produce a known or desired magnetic field for use in the sputtering operation. This process may save time in maintenance and setup of sputtering targets. Manufacturing efficiency and manufacturing flexibility thus may also be improved. The modular design may also minimize or reduce bending of magnetic bars. The smaller magnetic segments (smaller than the overall bar length) also may have higher flexibilities, when compared with a single magnetic bar that runs the entire length of the sputtering target. The minimization or reduction in bowing, warping, and/or sagging of the modular or magnetic elements, in turn, leads to increased uniformity of the magnetic field and thus of sputtering. In certain example embodiments of this invention, separating of the magnet carrier from the mounting may be used to reduces bending effects when the heights of the magnets are adjusted (e.g., when tuning the elements). Thus, the overall magnetic homogeneity and uniformity of the field may be increased.
Also, as will be described in further detail below, allowing the mounting device and magnet carrier device to be easily disconnected advantageously allows the adjustment of the magnets to reduce bending of the whole system. Also reduced may be mechanical impacts on the carrier related to adjustments and/or tuning, which would decrease the predictability of the system. In an example embodiment, moreover, stability may be increased, and the bending related to the mass and gravitation may be reduced by pre-bending the system to the opponent side and fixing it in such a way as to reduce bending during operation.
An example material which may be used in the tube (other than the magnets themselves) is a nonmagnetic stainless steel.
FIG. 2 shows a cross-section of a modular magnetic bar structure in accordance with an example embodiment of this invention. Meanwhile, FIG. 3 is a partial perspective view of the modular magnetic bar structure of FIG. 2 showing a central portion of the stationary magnet bar structure which is located inside of the rotating sputtering target tube; FIG. 4 is a partial perspective view of an end portion of the modular magnetic bar structure of FIGS. 2-3; and FIG. 5 is a perspective view of a significant portion of the modular magnet bar structure of FIGS. 2-4. The magnet bar structure of FIGS. 2-5 may be used in connection with a rotating magnetron sputtering apparatus as shown in FIG. 1, where the sputtering tube/target with the sputtering material thereon rotates around the stationary magnet structure.
Referring to FIGS. 2-5, elongated main mounting part (static profile or support) 202 is mounted on elongated hollow tube 201 and is connected to a magnet carrier support 204 and a magnet carrier or magnet carrier module 207. The hollow portion of tube 201 is indicated at 210. Mounting part 202 may be made up of one or multiple parts in different embodiments of this invention, but may include two spaced apart members as shown in FIG. 2 that are provided on opposite sides of tube 201. Magnet carrier 207 is elongated in shape in supports one or more elongated magnet segments 208. Each magnet bar is made up of a plurality of elongated magnet segments 208 arranged in a substantially linear manner, or in series (e.g., see FIGS. 2, 3 and 5). In other words, a magnet bar may be said to be a row of substantially aligned magnet portions. Immediately adjacent ones of the linearly arranged magnet segments 208 of a given magnet bar may be spaced apart from one another, or alternatively may abut one another, in different example embodiments of this invention. It can be seen in FIGS. 2-5 that three different magnet bars (each magnet bar being made up of a plurality of magnet segments 208 arranged in a substantially linear manner) are provided for this particular embodiment, although one, two, four or more magnet bars may be provided in alternative embodiments of this invention. In other words, while there are three substantially parallel magnet rows 208 shown in FIGS. 2-5, the assembly may instead have only two substantially parallel magnet rows, or alternatively may have four, five, etc. substantially parallel magnet rows in certain example instances. In addition to supporting the adjustable magnet segment(s) 208 of the respective magnet bars, the magnet carrier 207 also may optionally support end magnets 209 as shown in FIGS. 2 and 4. End magnets 209 are located at one or both ends of the carrier 207 as shown in FIGS. 4-5, and thus at one or both ends of the bars which are made up of the magnet segments 208. In certain example embodiments of this invention, a plurality of magnet carrier supports 204 are provided in series on each side of the carrier 207 along the length of the target, with one or more magnet segments 208 being mounted for adjustment via each carrier support 204. Generally, the mounting part 202 extends in a continuous manner along substantially the entire length of each side of tube 201. One or more magnet carriers 207 may be provided along the length of the tube 201 so as to be aligned in series, which each carrier 207 optionally being selectively adjustable with respect to position thereby permitting the position of the magnet segment(s) 208 mounted thereon to be selectively adjusted along with that of 207. In certain example instances, the magnet bar portion of the system may also include the support tube.
Thus, it will be appreciated that there may be provided a rotatable magnetron sputtering target comprising a rotatable target tube (see 14 in FIG. 1) comprising sputtering material on an outer surface thereof to be sputter deposited on a substrate (e.g., onto a glass substrate or the like), a magnet bar structure provided within the rotatable target tube 14, wherein the magnet bar structure is stationary when the rotatable tube 14 is rotating during sputtering, and wherein the magnet bar structure comprises at least one elongated magnet bar which includes a plurality of different magnet segments 208 that are aligned in a substantially linear manner along at least a substantial portion of the magnet bar structure. The magnet segments 208 are independently adjustable in certain example embodiments, relative to one or more other magnet segments of the bar; and in certain example embodiments the modules may be linked in order to prevent or reduce a gap between adjacent magnets which could create plasma issues.
In certain example embodiments, the connection between mounting part 202 and magnet carrier support 204 is made using screws 206a-b. However, it will be appreciated that other methods or techniques of attaching mounting part 202 to magnet carrier support 204 may instead be used. It also will be appreciated that mounting part 202 and magnet carrier support 204 may be fixedly attached to each other, though this arrangement is less preferable because, for example, it potentially limits the degree to which the magnetic elements 208 can be tuned/adjusted. The advantages of tuning using the techniques disclosed herein are further described below.
According to an example embodiment of this invention, turning one of screws 206a-b adjusts the distance between the corresponding magnet segment 208 which is located closest to the screw and tube 201; and optionally turning the other screw which is also located adjacent the segment 208 but across the tube 201 may fix the adjustment. In such an example embodiment, it will be appreciated that the handedness may be reversed—e.g., screw 206a may be used for adjusting the height and screw 206b may be used for fixing the height, or vice versa. It also will be appreciated that more than two screws may be used to fix each magnetic carrier support 204 to mounting part 202. By adjusting the position of magnet carrier support 204 relative to mounting part 202 using one of the screws, the height/position of magnet bar segment(s) 208 mounted on that particular support 204 will also be adjusted in a desirable manner thereby permitting one to easily adjust the positions of magnet segments and thus adjust the magnetic field to be used during sputtering. Using such an arrangement, the magnetic field may be adjusted for substantial uniformity with a very fine accuracy. For purposes of example and without limitation, one turn of a screw (206a or 206b) in certain example embodiments may translate into about a 0.8 mm adjustment in height of the closest corresponding magnet segment 208. It will be appreciated that in other example embodiments, both of screws 206a-b may be used for height adjustment and/or for fixing the height.
FIG. 3 illustrates part of the structure of FIGS. 2 and 4-5, in a partial perspective view. Rollers 302a-b may be mounted, directly or indirectly, on mounting part or support 202 and are adapted to come into rotating contact with the inner wall of the rotating outer tube 14 which supports the target material to be sputtered. Thus, the rollers 302a-b prevent the inner rotating wall of the target tube (see rotating target tube 14 in FIG. 1 which rotates about axis 20) from contacting or damaging the mounting part 202, tube 201, and magnets 208-209. In other words, rollers 302a-b may be located in such a way as to prevent or reduce damage to the magnetic elements 208-209 and/or the rotating outer tube 14 in case the magnetic elements become too close to the walls of the rotating outer tube 14 as a result of shimming and/or adjustments via screws 206a-b. It will be appreciated that the position of the rollers may also help avoid and/or reduce other potential mechanical influences.
Water may be fed through the magnet bar structure from one side via an inlet and out through the other side via an outlet, for cooling purposes. FIG. 4 illustrates holes for water inlet and/or outlet in accordance with an example embodiment. The assembly includes several side inlet/outlet holes 402a-b as well as a front inlet/outlet hole 404 for water distribution, for purposes of cooling the structure during sputtering operations. This arrangement enables the water or other coolant flow to be varied and more precisely defined, as optional steel components (not shown) may be attached to the holes to vary the sizes thereof, independently and adjustably. In certain example embodiments the inlet/outlet segments may be screwed or other wise attached to the magnetic segments, potentially providing more opportunities for modifications and/or fine adjustments.
FIG. 5 illustrates an elongated portion of the magnet bar structure of FIGS. 2-4 (or course, the rotating target tube which rotates around the stationary magnet bar structure is not shown in FIGS. 2-5 for purposes of simplicity). It will be appreciated that magnetic segments 208 are attached to magnet carrier supports and corresponding magnet carrier modules 207. Attaching magnet segments 208 to magnetic carrier modules in this way allows the height of the magnetic segments 208 to be adjusted, as noted above, thus increasing and/or decreasing the magnetic field and sputter rate as desired. One conventional magnet bar tuning method involved the addition of small plates (shims) under a magnet bar extending the length of the target. However, this arrangement did not allow for good, long range uniform tuning of the magnetic field, which is now possible with certain example embodiments of this invention. Thus, in certain example non-limiting embodiments of this invention, such shims are not needed. As noted above, in certain example embodiments of this invention a technique for tuning magnet segment 208 positions involves adjustment of one or more screws of the like. Additionally, in certain example embodiments, a shortened magnet carrier module length may allow for yet more fine adjustment to the magnetic field. This modular system may allow magnet segments to be easily replaced. For example, magnet segments 208 and/or carrier modules 207 may be selectively replaced based on, for example, whether they are defective, damaged, warped, bent, broken, etc. Individual magnet segments may be replaced without replacing the entire magnet bar which is made up of a plurality of magnet segments 208 aligned in a linear manner. This may allow for easier installation and/or maintenance, while reducing replacement times and costs.
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
Patent Application
20080047831
