Abstract:
A substrate processing method includes following steps. Multiple sawing blades are applied to a substrate for forming multiple side-by-side grooves. Each groove includes a short edge, and opposite a first long edge and a second long edge. A milling blade is used for milling one of the grooves. During the milling process the milling blade starts at a feed point and moves along a first feed path head toward the short edge, away from the groove, and intersects with the first long edge of the groove. The milling blade then proceeds to a second feed path, followed by moving to the third feed path, and eventually stops at an end point. The third feed path leads the milling blade toward the groove, away from the short edge of the groove, and then intersects with a second long edge of the groove before it eventually stops at the end point.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The invention relates to a substrate processing method, and more specifically, to a processing method for substrates containing grooves. 
         [0003]    2. Background 
         [0004]    Heretofore, light emitting diodes (LEDs) are usually mounted on an aluminum substrate with good thermal conductivity that serves as a heat sink to dissipate heat induced by the LED during operation. 
         [0005]    The general concept for the production of LED lighting devices is to attach the LED to an aluminum substrate whose surface is covered with pre-formed circuit layouts. As an example, consider a Liquid-crystal display television (LCD TV) employing the LEDs. In this example, multiple LED units are mounted on a long strip of aluminum substrate to form an ultra-thin TV display screen. The usual method used for producing the strips of aluminum substrate is to form several photolithography circuit layouts on a flat aluminum substrate plate (for instance, a rectangular plate of 600 mm*480 mm), followed by forming multiple grooves adjacent to each other in parallel on the aluminum substrate plate without causing damage to the circuit layouts. These grooves cut to the back surface of the aluminum plate without separating individual substrate strip from the aluminum plate, and all substrate strips remain attached at both ends. Next, multiple units of LED are die-bonded to each strip of substrate and finally adjacent LED substrates are severed off at both ends and separated. 
         [0006]    There are two approaches for creating multiple adjacent grooves on an aluminum substrate plate in parallel: the first is die stamping, which casts grooves on the aluminum substrate, and the second is mill cutting, which applies milling blades on the aluminum substrate. 
         [0007]    The die stamping approach may leave burrs along the edges of the cuts and cause deformation to the substrate plate, limiting further processing afterward. As a result, die stamping may lead to products of less satisfactory quality and may result in yield loss. The die sampling method requires different mold tools for producing different sizes of groove, resulting in a longer preparation cycle and increased costs. There are also limits in the size and ratio of dimensions of groove that the die stamping method can perform. To produce a long groove, it may take multiple molds to complete the die stamping process. Moreover, in some cases, the aluminum substrate of LED-based lighting devices is covered with a layer of ceramic material. Due to its brittle character, the ceramic layer on the surface of an aluminum substrate makes the die stamping method unsuitable. Furthermore, in the case of substrates made of aluminum alloy, the extreme hardness of the aluminum alloy makes the die stamping impossible to perform. The complexity of the production process and the reasons outlined above render the die stamping approach less advantageous for making large-sized devices, particularly in the case of display monitors and fluorescent lighting devices. 
         [0008]    On the other hand, the method of using cutting with milling blades to groove the aluminum substrate improves product quality and does not limit the processing of long grooves from which the die stamping method suffers. Previously developed mill cutting methods use a single cutter, and to form ten grooves the cutter includes repeating the same process ten times. The longer processing time of a single blade system results low productivity and makes the cutting method less competitive for mass production. 
       SUMMARY 
       [0009]    In view of the problems of current methods of substrate processing discussed above, the invention provides a substrate cutting method for improved efficiency for substrate processing. 
         [0010]    In some embodiments, the substrate cutting method includes following steps. A cutting machine with multiple sawing blades are arranged in parallel is provided. Multiple grooves in parallel on a substrate plate are formed by the sawing blades of the cutting machine. Each groove includes a first long edge, a second long edge opposite to the first long edge and a short edge located at ends of both the first and second long edges. A milling blade of a milling machine is used to mill one of the grooves by starting at a feed point at a distance from the short edge of the groove. The milling blade moves along the first feed path toward the short edge of the groove, away from the groove itself and intersects with the first long edge of the groove. The milling blade proceeds along a second feed path following the first feed path, and continues to the third feed path away from the short edge of the groove, toward the groove itself, and intersecting with the second long edge of the groove before the blade stops at an end point and a distance from the short edge of the groove, thus removing a portion of the substrate material of the short edge. 
         [0011]    In some embodiments, the substrate processing method comprises following steps. A substrate with at least one groove, having a first long edge, a second long edge and a short edge located at the end of both the first and second long edges is provided. A milling blade is used to mill one of the grooves by milling from a feed point at a distance from the short edge of the groove, moving along the first given feed path toward the short edge of the groove, away from the groove itself and intersecting with the first long edge of the groove. Then, the blade is moved along the second feed path following the first feed path. Then, the blade is moved along the third feed path away from the short edge of the groove and toward the groove itself, and intersecting with the second long edge of the groove before stopping at an end point and a distance from the short side of the groove. Accordingly, a portion of the substrate material of the short edge of the groove is removed. 
         [0012]    In some embodiments, the substrate processing method comprises following steps. A substrate with at least one groove, having a first long edge, a second long edge and a short edge located at the end of both the first and second long edges is provided. A milling blade is used to mill one of the grooves by milling from a feed point at a distance from the short edge of the groove, moving along the first given feed path toward the short edge of the groove, away from the groove itself and intersecting with the first long edge of the groove. Then, the blade is moved along the second feed path following the first feed path. Then, the blade is moved along the third feed path away from the short edge of the groove and toward the groove itself, and intersecting with the second long edge of the groove before stopping at an end point and a distance from the short side of the groove. Accordingly, a portion of the substrate material of the short edge of the groove is removed. 
         [0013]    In the substrate processing method of some embodiments described above, a set of sawing blades is arranged side by side to produce multiple lines of groove in parallel during a single step, thus reducing processing time. 
         [0014]    Giving the setting to include a first feed path intersecting with a first long edge of the groove, moving toward the short edge of the groove, away from the groove itself, followed by a third feed path heading toward the groove itself and away from the short edge, and intersecting with a second long edge of the groove, the short edge of the groove is cleanly processed and includes smooth surface joints to a first long edge and a second long edge of the groove for further processing afterward. 
         [0015]    The features, implementation and advantages of the invention include been manifested in the context of the state of the art, along with the accompanying drawings in which the structure of the invention is shown by examples. 
         [0016]    The following descriptions are exemplary embodiments only, and are not intended to limit the scope, applicability or configuration of the invention in any way. Rather, the following descriptions provide convenient illustrative examples for implementing the invention. Various changes to the described embodiments may be made in the function and arrangement of the elements described without departing from the scope of the invention as set forth in the claims herein. 
     
    
     
       DRAWINGS 
         [0017]    The present disclosure will become more fully understood from the detailed description given herein below for illustration only, and thus are not limitative of the present disclosure, and wherein: 
           [0018]      FIG. 1  is a flow chart of a method for processing a LED substrate in accordance with an embodiment; 
           [0019]      FIG. 2A  is an embodiment of the composite layout of a processing machine; 
           [0020]      FIG. 2B  is a side view showing an embodiment of the composite layout of a processing machine; 
           [0021]      FIG. 2C  is an embodiment of a portion of a processing machine; 
           [0022]      FIG. 3  shows grooves at the top of a substrate plate produced by sawing blades in accordance with an embodiment; 
           [0023]      FIG. 4  shows grooves in a top of a substrate plate produced by sawing blades in accordance with another embodiment; 
           [0024]      FIG. 5A  shows grooves in a top of a substrate plate produced by sawing blades in accordance with yet another embodiment; 
           [0025]      FIG. 5B  shows the processed substrate in the embodiment described in  FIG. 5 ; 
           [0026]      FIG. 6A  is a partial structural diagram of a groove of an embodiment; 
           [0027]      FIG. 6B  is a sectional view of a groove taken along the line  6 B in  FIG. 6A ; 
           [0028]      FIG. 7  presents a cutaway view of a substrate of another embodiment; 
           [0029]      FIG. 8  is an enlarged schematic view of a feed path of the blade in an embodiment; 
           [0030]      FIG. 9  is an enlarged schematic view of a groove after the milling process in an embodiment; 
           [0031]      FIG. 10  shows a schematic view of a feed path of the milling blade in another embodiment; 
       
    
    
     DETAILED DESCRIPTION 
       [0032]    With reference to  FIGS. 1 ,  2 A,  2 B,  2 C and  3 , the scheme and implementation of the substrate processing method are presented herein.  FIG. 1  is a flow chart of a method for processing substrates in accordance with an embodiment.  FIG. 2A  shows an embodiment of the composite layout of a processing machine  FIG. 2B  is a side view showing the composite layout of the processing machine.  FIG. 2C  is a partial structural view of the processing machine.  FIG. 3  shows grooves at the top of a substrate plate produced by sawing blades in accordance with the embodiment. 
         [0033]      FIGS. 2A to 2C  illustrate a composite processing machine  10  that includes a sawing device  100  and a milling device  200 . The sawing device  100  includes multiple sawing blades  110  and the milling device  200  includes a mill blade  210  (S 1 ). 
         [0034]    Specifically, the composite processing machine  10  includes a machine base  11  on which the sawing device  100  and the milling device  200  are disposed. The sawing device  100  and the milling device  200  are on the machine base  11  in the embodiment, while both can be on two separate machine bases in other embodiments. 
         [0035]    The machine base  11  includes a table top  16  where a substrate plate is placed. The composite processing machine  10  further includes an X-axis guide rail  14 , a Z-axis guide rail  12  and the Y-axis guide rail  15  stored on the machine base  11 . 
         [0036]    The sawing device  100  and the milling device  200  are attached to the X-axis guide rail  14  and Z-axial guide rail  12 , above against the table top  16 , and are powered by, for instance, a linear motor to move along the directions of the X-axis guide rail  14  or Z-axial guide rail relative to the table top  16 . Table top  16  is mounted on the Y-axial guide rail  15  and is powered by, for example, a linear motor to travel in the direction of the Y-axial guide rail  15  relative to the machine base  11 . 
         [0037]    The sawing device  100  includes five sawing blades  110  disposed in parallel, attached to and arranged coaxially with a shift  150 . The number of blades specified in the embodiment can vary, without departing from the scope of the invention, depending on the circumstances and the needs of the users. 
         [0038]    Next,  FIG. 6A  is a partial structural diagram of a groove of an embodiment. Refer to  FIGS. 3 and 6A , the sawing device  100  is applied on the substrate plate  30  to form multiple grooves  300  side by side, corresponding to the sawing blades  110 . Each groove  300  comprises a first long edge  301 , a second long edge  302 , and a short edge  303  (S 2 ) located at one end of both edges of  301  and  302 . (S 2 ). 
         [0039]    In this embodiment, the substrate plate  30  is a circuit board substrate, and more specifically but not limited to, a LED aluminum substrate. Having multiple sawing blades  110  used in parallel, the sawing device  100  can produce multiple lines of groove in parallel in a single step, thus reducing processing time. 
         [0040]    Even though the diameters of the sawing blades  110  of the embodiment are identical, dimensions of a set of sawing blades may be different, without departing from the scope of the invention. For example,  FIG. 4  illustrates a set of sawing blades  110  comprising a group of first blades  111  and a second blade  112 , attached to and arranged coaxially with a shift  150 . The second blade  112  of a larger diameter than those of first blades  111  is adjacent to first blades  111 . The grooves  300  include a long groove  320  and a plurality of short grooves  310  adjacent to the long groove  320 . The short grooves  310  are produced by the first blades  111  cutting through the substrate plate  30  and the long groove  320  is produced by the second blade  112  cutting through the substrate plate  30 . 
         [0041]    In  FIG. 5A  illustrating another embodiment, a set of sawing blades  110  comprising several first blades  111  and two second blades  112 , are attached parallel to and arranged coaxially with a shift  150 . All first blades  111  are installed between two second blades  112  of a larger diameter than those of first blades  111 . 
         [0042]    The grooves  300  include two long grooves  320  and multiple short grooves  310  adjacent to and sandwiched by the two long grooves  320  on both sides, generated by a set of first blades  111  and two second blades  112  respectively cutting through a substrate plate  30 . The substrate plate  30  with a set of short grooves  310  and two long grooves  320  being created, as shown in  FIG. 5A , can be further processed, such as, using milling blades or sawing blades to produce two cutting slots  330  in parallel and connecting ends of two separate long grooves  320  of both sides, as presented in  FIG. 5B . Thus, a piece of rectangular-shaped substrate  31  containing a set of short grooves  310  and edged by two cutting slots  330  and two long grooves  320 , can be separated from a substrate plate  30  and become a unit of a semi-finished panel. 
         [0043]    Refer to  FIGS. 6A ,  6 B,  7 ,  8  and  1 .  FIG. 6B  is a sectional view of a groove taken along the line  6 B in  FIG. 6A .  FIG. 7  is a cutaway view of a substrate of another embodiment;  FIG. 8  is an enlarged schematic view of a feed path of the blade in an embodiment. As the plurality of grooves  300  are created in parallel on the substrate plate  30  by a set of sawing blades  110 , the short edges  303  at both ends of each groove are un-burnished, but rather have roughness and sharp burrs  304 . The curve-shaped sawing blades  110  leaves a trajectory and shaggy burrs  304  at the short edge  303  of a groove  300 , as illustrated in  FIG. 6B . Given the case that the short edges  303  of grooves  300  may be further modified to be mechanical slots, it is necessary to remove burrs  304  and to smooth irregularities. To gain higher productivity, in some embodiments, a set of sawing blades  110  process two layers of substrate plate  30  and  30 ′, with one atop the other, simultaneously during actual production, as shown in  FIG. 7 . Again, because of the curve-shaped sawing blades  110 , lengths of the grooves  300  and  300 ′ formed on substrate plate  30  and the one  30 ′ below respectively are not equal in the embodiment. Thus, a method for de-burring and polishing surfaces of grooves  300  and  300 ′ is needed for the substrate processing system. 
         [0044]    Thus, once the grooves  300  on a substrate plate  30  are formed by a sawing device  100  of the composite processing machine  10 , the grooves  300  are then polished and processed by a milling device  200 . To remove the disproportion and roughness, a mill blade  210  of a milling device  200 , presented in  FIG. 2B , begins at a selected point a, a distance L 4  away from the short edge  303  of the groove, moves along a first feed path D 1 , away from the groove  300 , toward the short edge  303  and intersecting with the first long edge  301 (S 3 ). The distance L 4 , for example, is, but not limited to 3 cm and various lengths can be used for the distance L 4 . 
         [0045]    In other words, the feed point a of feeding the milling blade  210  is selected inside the groove  300 ; the first feed path D 1  stretches from the feed point a toward a short edge  303 , having a cutting edge angle θ 1  between a cutting direction and a long edge  301  of the groove  300 . The next step is to continue to move the milling blade  210  in a second feed path D 2  following the first feed path D 1 . In addition, the second feed path D 2 , which is a semicircular-shaped path, lays substantially parallel and closely next to the short edge  303  outside the groove  300 , as shown in  FIG. 8 . In addition to being angular, the shapes of a second feed path D 2  can be different, such as, polygonal as demonstrated in  FIG. 10 , or a straight line in some embodiments. 
         [0046]    The milling blade  210  is then directed to a third feed path D 3 , which is extended from the second feed path D 2 , to remove partial material from the substrate plate  30  at the short edge  303  before it reaches an end point b, wherein the end point b is at the distance L 4  away from the short edge  303  of the groove  300 . The third feed path D 3  heads toward the groove  300 , away from the short edge  303  and intersects with the second long edge  302  (S 5 ). The distance L 4  is, but not limited to, 3 cm and various lengths can be used for the distance L 4 . Furthermore, the end point b of falls inside the groove  300  following the feed path D 3  that moves away from the short edge  303  and includes the cutting edge angle θ 2  between the cutting direction and the second long edge  302  of the groove  300 . Thus, a processing path comprises the first feed path D 1 , the second feed path D 2  and the third feed path D 3  forming an angular edge around the short edge  303 . The milling blade begins at the feed point a, travels along the first feed path D 1 , the second feed path D 2  and the third feed path D 3 , and moves toward the end point b, to cleanly and smoothly remove burrs  304  on the short edge  303 , as shown in  FIG. 9 . Giving the setting of the processing path to include an acute angle θ 1  between the first feed path D 1  and the first long side  301  plus the acute angle θ 2  between the second feed path D 3  and the second long edge  302 , the milling blade  210  is able to form a milled edge  305  on the substrate plate  30  by milling along a first feed path D 1 , a second feed path D 2 , and a third feed path D 3  with smooth connections to both the first long edge  301  and the second long edge  302 , as shown in  FIG. 9 . Such setting can avoid uneven or unsmooth surface near the joints of the milled edge  305  to the first long edge  301  or the milled edge  305  to a second long edge  302  due to precision deviations of milling blade  210  caused by positioning tolerances, making further process easier and subsequently preventing light leakage once LED is mounted. In the preferred embodiment, as described in  FIG. 8 , the first long edge  301  and the second long edge  302  of the groove  300  are apart by the distance L 1 , equivalent to a design value or a production target value L±tolerance value t. The distance L 2  between the feed point a and the end point b of a processing path is L−t, whereas the distance L 3  between an end point c of a first feed path D 1  (equivalent to a starting point of a second feed path D 2 ) and a starting point d of a third feed path D 3  (the same as an end of a second feed path D 2 ) is L+t. For example, if the distance L 1  is 2.0±0.1 cm, then the distance L 2  is 1.9 cm and distance L 3  2.1 cm. As a result, even disregarding what the tolerance value t of the distance L 1  between the first long edge  301  and the second long edge  302  is, the feed point a and end point b definitely reside within the groove  300  as well as the end point c of the first feed path D 1  and the starting point of the third feed path D 3  outside the groove  300  in the substrate plate  30 . Accordingly, in reference to the parameter settings of the distance L 2  and the distance L 3 , once the width (distance L 1 ) of the groove  300  in the substrate plate  30  is within the tolerance margin, the process program is applicable to every substrate plate  30  without further adjustments or modifications. The substrate process method described in the embodiments relies on multiple cutting blades used in parallel to form a set of grooves side by side in one operational step. In addition, by including two acute angles in the process settings, one angle positioned between a first feed path and a first long edge of the groove as well as the other angle between a third feed path and a second long edge of the groove, the milling blades can clean up the short edge of the groove having smooth surface joints to a first long edge and a second long edge of the groove. Subsequently, the outcomes of the embodiments make further process easier afterward and prevent light leakage once LED is mounted. 
         [0047]    Using sawing(cutting) and milling blades to process substrate plates as described in the embodiments, can overcome process problems that die stamping tools or mold tools currently include to face, thus increasing production yield rate and efficiency, and can operate without restrictions on groove dimensions and substrate materials and consequently, reduce wasted material. 
         [0048]    The foregoing description of the exemplary embodiments of the invention has been presented only for the purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in light of the above teaching. 
         [0049]    The embodiments were chosen and described in order to explain the principles of the invention and their practical application so as to activate others skilled in the art to utilize the invention and various embodiments and with various modifications as are suited to the particular use contemplated. Alternative embodiments will become apparent to those skilled in the art to which the present invention pertains without departing from its spirit and scope. Accordingly, the scope of the present invention is defined by the appended claims rather than the foregoing description and the exemplary embodiments described therein.