Patent Publication Number: US-2009236221-A1

Title: Magnetron sputtering target structure and apparatus having the same

Description:
FIELD OF THE PRESENT INVENTION 
     The present invention relates a magnetron sputtering target structure and an apparatus having the same. 
     BACKGROUND OF THE PRESENT INVENTION 
     Magnetron sputtering technology is a conventional technology employed in coating technology, the basic operating principle of which is to impact a surface of a target material with ions of high energy in plasmas produced with a radio frequency power source or a direct current power source and deposit particles escaping from the surface of the target material onto a surface of a substrate, so as to form a film on the surface of the substrate. 
     A conventional magnetron sputtering target structure employed in a magnetron sputtering coating apparatus is generally designed as a fixed type. As show in  FIG. 1 , magnetic bars  11  are fixed onto magnetic bar holding rods  12  in a fixed state. In such a structure, N-pole magnets and S-pole magnets of the magnetic bars produce non-uniform magnetic field, which in turn causes non-uniform distribution of electron concentration, and therefore, the consumption area in a target material  13  is limited within a narrow region, as shown in  FIG. 2 . After a long-time operation, a very deep etching groove is formed in the consumption area of the target material  13 , which affects the stable working of magnetron sputtering target structure and the effect of sputtering, and moreover, the target material is wasted. 
     In order to improve the uniformity of electron concentration, a reciprocating magnetron sputtering target structure is suggested in a conventional design. As shown in  FIGS. 3A ,  3 B and  3 C, magnetic bars  18  are fixed onto a magnetic bar fixing board  14  placed on a nut  15  and reciprocate through the rotating of a screw rod  17  provided on a screw fixing platen  16 . However, the travel of the reciprocating movement of the magnetic bars  18  is limited by space and thus is insufficient. Therefore, the magnetic field distribution uniformity can not be substantially improved, and the aims of uniformly consuming target materials and prolonging service life of target materials can not be achieved. 
     SUMMARY OF THE INVENTION 
     An embodiment of the invention provides a magnetron sputtering target structure, comprising a transmission device, at least two transmission shafts, and a plurality of magnetic bars. The transmission device winds around the transmission shafts and thus forms a transmission structure, and the magnetic bars are disposed in parallel on the transmission device. 
     Another embodiment of the invention provides a magnetron sputtering target apparatus comprising a magnetron sputtering target structure and a target material. The magnetron sputtering target structure comprises a transmission device, at least two transmission shafts, and a plurality of magnetic bars, the transmission device winds around the transmission shafts and thus forms a transmission structure, and the magnetic bars are disposed in parallel on the transmission device. The target material is located outside of the transmission structure. 
     With embodiments of the invention, the magnets can be moved regularly by using a transmission device, and a parallel and uniform magnetic field can be obtained, which therefore enables a very uniform consumption of the target material and avoids the problem of partial overconsumption, thus improves the utilization rate and prolongs the service lifetime of target materials. 
     Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from the following detailed description. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description given hereinafter and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention and wherein: 
         FIG. 1  is a plan schematic view of a conventional fixed type magnetron sputtering target structure; 
         FIG. 2  is a schematic diagram illustrating the relationship between electron distribution and target material consumption when employing the structure shown in  FIG. 1 ; 
         FIG. 3A  is a plan schematic view illustrating a conventional reciprocating type magnetron sputtering target structure; 
         FIG. 3B  is a longitudinal section view taken along line A-A′ of the reciprocating type magnetron sputtering target structure; 
         FIG. 3C  is a transverse section view taken along line B-B′ of the reciprocating type magnetron sputtering target structure; 
         FIG. 4A  is a plan schematic view illustrating the magnetron sputtering target device according to a first embodiment of the invention; 
         FIG. 4B  is a transverse section view taken along line C-C′ of the magnetron sputtering target structure of  FIG. 4A ; and 
         FIG. 5  is a schematic view illustrating a second embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiment 1 
     As shown in  FIGS. 4A and 4B , a magnetron sputtering target apparatus comprises a magnetron sputtering target structure and a target material  24  located outside of the magnetron sputtering target structure. The magnetron sputtering target structure comprises a plurality of magnetic bars  23 , two rotating shafts  22 , and a transmission device  21  which winds around the rotating shafts  22  to form a transmission structure. The magnetic bars  23  comprise positive magnetic bars  23 - 1  and negative magnetic bars  23 - 2 , which are disposed on the transmission device  21  alternatively and in parallel. In driving the transmission device  21  to rotate with the rotating shaft  22 , the magnetic bars  23  move regularly together with the transmission device  21 . 
     The magnetic bars  23  arranged on the transmission device  21  is constructed so that the N-pole magnet of the positive magnetic bars  23 - 1  is of a long ring shape, and the S-pole magnet of the positive magnetic bars  23 - 1  is of a strip shape and is located within the long ring-shaped N-pole magnet, and the S-pole magnet of the negative magnetic bars  23 - 2  is of a long ring shape, and the N-pole magnet of the negative magnetic bars  23 - 2  is of a strip shape and is located within the long ring-shaped S-pole magnet. 
     Specifically, the transmission device may be a chain transmission device. Chain transmission is a kind of engagement transmission in which chain is used for flexible traction between two sprockets on the two parallel rotating shafts  22  to transfer motion and power. Since the chain transmission has no elastic sliding and slipping, it can keep an accurate average transmission ratio as well as a high transmission efficiency; since it is not necessary to tighten the chain to a great extent, the needed shaft compressing force is small; transmission power is high and overload capacity is strong; chain transmission works well at a low-speed and under a heavy burden; and it is also applicable in a harsh environment, such as dusty, oil contamination, corrosive, and high-strength situations. Specifically, the chain used in chain transmission device may be driving chains, lifting chains and traction chains. 
     In addition, the transmission device  21  may also be a belt transmission device. The belt transmission device is advantageous due to its high elasticity, cushioning, vibration absorption, stable transmission, no lubrication and cleaning required, and low noise, and the like. Once overloaded, a transmission belt slips on the rotating shaft  22 , thus preventing damage to the other parts and acting as a safety protection means. Moreover, the belt transmission device is also applicable for the case of a relatively long centre distance and advantageous due to its simple structure, low cost, convenience in assemble, and disassemble. Specifically, the belt transmission device may be a friction type belt transmission device or an engagement type belt transmission device. 
     The magnetron sputtering target device according to this embodiment differs from not only the conventional fixed type magnetron sputtering target device but also the conventional reciprocating magnetron sputtering target device. The magnetron sputtering target device according to the invention can make the magnetic bars  23  move regularly together with rotate of the transmission device  21 , and for example, it may drive the target strips  23  to rotate in a uniform speed by the transmission device  21 , thus generates a uniform magnetic field, improves the consumption area of the target materials surface substantially, increases the occupation ratio, prolongs the service life of the target materials, and also improves the effect of sputtering coating. 
     Embodiment 2 
     As shown in  FIG. 5 , this embodiment differs from embodiment 1 in that an additional target material  25  is disposed on another side of the magnetron sputtering target structure. In such a manner, the consumption area achieves the same substantial improvement, and this embodiment can farther increase the working efficiency of magnetron sputtering coating device, besides improving the utility ratio and prolonging the service life of target materials. 
     The embodiments of the invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to those skilled in the art are intended to be comprised within the scope of the following claims.