Abstract:
An apparatus for creating cuts or scores in a substrate includes a support structure, one or more blades and a secondary support. The support structure has one or more cavities, which collectively define a substantially planar reference surface. Each blade has a cutting edge, which contacts the substantially planar reference surface, and each blade is biased against the substantially planar reference surface. An opening is defined through the substantially planar reference surface of the support structure to expose a portion of the cutting edge of each blade. The secondary support is capable of holding a portion of the substrate between the secondary support and in contact with the exposed portions of the cutting edges of the blades.

Description:
BACKGROUND  
       [0001]     The present invention relates to an apparatus for making cover tapes that are used with tapes for carrying components.  
         [0002]     In manufacturing settings, it is often necessary to hold and transport components. For example, in the field of electronics circuit assembly, electronic components are often carried from a supply of components to a specific location on a circuit board for attachment thereto. The components may be of several different types, including surface mount components. Particular examples include memory chips, integrated circuit chips, resistors, connectors, processors, capacitors, gate arrays, etc. It is possible to transport small and delicate components using a carrier tape/cover tape system, such as that disclosed in U.S. Pat. No. 5,325,654.  
         [0003]     The electronic industry is continually moving towards smaller devices and thus smaller components, which in turn require more delicate and precise removal of such components from the carrier tape/cover tape system. Most known cover tapes use heat activated adhesive (HAA) or pressure sensitive adhesive (PSA) to bond the cover tape to the carrier tape. Removal of the components is done by first carefully peeling or debonding the cover tape off of the carrier tape to expose the component to vacuum nozzles or other component handling equipment for safe component removal.  
         [0004]     However, known cover tapes present several operational difficulties. For instance, peeling the cover tape from the carrier tape can create “shocky”, rough, nonuniform and inconsistent peels, which cause movement of the carrier tape/cover tape that can displace the small components. Shocky peels have also been known to eject the small components out of the pocket in the carrier tape, thus causing miss-picks and eventual shut down of automated component handling equipment.  
         [0005]     The peel force of adhesive cover tape can vary considerably depending on the width of the cover tape and the type of carrier tape used. Wider HAA cover tapes require higher heat to get secure bonds. Likewise, wider PSA cover tapes have lower peel forces and require wider adhesive exposure to get secure bonds. In addition, cover tapes that are designed for one type of carrier tape (e.g., polystyrene) do not always have good performance from other types of carrier material (e.g., polycarbonate). Even if cover tapes do nominally work with different types of carrier tapes, they may have less than optimum peel force and nonuniform peels. Moreover, HAA cover tapes also have poor stability as the peel force degrades with time and temperature.  
         [0006]     Additionally, known cover tapes present difficulties in storing and transporting the cover tape. For instance, adhesive “squeeze-out” can occur when adhesives on a bottom surface of a tape migrate and deform under pressure and/or heat such that adhesive moves beyond the edges of the tape. This is problematic, as it can cause adhesives to adhere in undesired locations, lead to contamination, necessitate undesired cleaning, lessen aesthetic values, as well as present other problems such as undesired equipment downtime. Moreover, where a cover tape made of a flat film (i.e., a film without recesses) is wound upon itself, it can cause undesired sagging in between adhesive stripes, which leads to an unstable roll.  
       BRIEF SUMMARY  
       [0007]     In one aspect of the present invention, an apparatus for creating cuts or scores in a substrate includes a support structure, one or more blades and a secondary support. The support structure has one or more cavities, which collectively define a substantially planar reference surface. Each blade has a cutting edge, which contacts the substantially planar reference surface, and each blade is biased against the substantially planar reference surface. An opening is defined through the substantially planar reference surface of the support structure to expose a portion of the cutting edge of each blade. The secondary support is capable of holding a portion of the substrate between the secondary support and in contact with the exposed portions of the cutting edges of the blades.  
         [0008]     The above summary is not intended to describe each disclosed embodiment or every implementation of the present invention. The figures and the detailed description, which follow, more particularly exemplify illustrative embodiments. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]      FIG. 1  is a cross-sectional schematic view of a cover tape according to the present invention.  
         [0010]      FIG. 2  is a cross-sectional schematic view of another embodiment of a cover tape according to the present invention.  
         [0011]      FIG. 3  is a cross-sectional schematic view of another embodiment of a cover tape according to the present invention.  
         [0012]      FIG. 4A  is a cross-sectional schematic view of another embodiment of a cover tape according to the present invention.  
         [0013]      FIG. 4B  is a cross-sectional schematic view of another embodiment of a cover tape according to the present invention.  
         [0014]      FIG. 5  is a cross-sectional schematic view of the cover tape of  FIG. 1  after heat and pressure have been applied.  
         [0015]      FIG. 6  is a cross-sectional schematic side view of a portion of a roll of cover tape according to the present invention.  
         [0016]      FIG. 7  is a perspective view of a carrier tape/cover tape system according to the present invention, showing separation of the cover tape therefrom.  
         [0017]      FIG. 8  is a schematic side view of a cover tape scoring apparatus according to the present invention.  
         [0018]      FIG. 9  is a cross-sectional schematic side view of a portion of the scoring apparatus of  FIG. 8 .  
         [0019]      FIG. 10  is a schematic back view of a portion of the scoring apparatus of  FIGS. 8 and 9 .  
         [0020]      FIG. 11A  is a cross-sectional schematic view of an embodiment of a series of cover tapes according to the present invention.  
         [0021]      FIG. 11B  is a cross-sectional schematic view of another embodiment of a series of cover tape according to the present invention. 
     
    
       [0022]     While the above-identified drawing figures set forth several embodiments of the invention, other embodiments are also contemplated, as noted in the discussion. In all cases, this disclosure presents the invention by way of representation and not limitation. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope and spirit of the principles of the invention. The figures may not be drawn to scale. Like reference numbers have been used throughout the figures to denote like parts.  
       DETAILED DESCRIPTION  
       [0023]     Aspects of the present invention relate to a cover tape, a carrier tape/cover tape system, as well as to a method and apparatus for making a cover tape. A cover tape according to the present invention can be adhered to a carrier tape, which can hold components for storage and transportation. The cover tape can cover pockets in the carrier tape that can hold components, and has a portion that can be separated from the system to expose the pockets in the carrier tape. Tear enabling features on the cover tape permit the portion of the cover tape to be separated from other portions of the cover tape (and a carrier tape to which the cover tape was adhered) with a substantially consistent and uniform separation force, which reduces the possibility of undesired movement of components held by the carrier tape during the separation process. As used herein, the term “tear” means generally controlled separation of portions of a component. In addition, the cover tape according to the present invention provides recesses along the longitudinal edges of the cover tape, which help the cover tape maintain a relatively flat profile during storage and application. The location of the adhesive is spaced from the edge of the cover tape, which helps prevent contamination of the adhesive and undesired adhesion of the adhesive to other surfaces, such as cover tape handling equipment.  
         [0024]      FIG. 1  is a cross-sectional schematic view of a cover tape  20  suitable for use in a carrier tape/cover tape system. The cover tape  20  includes an elongate film  22  that has opposed longitudinal edges  24  and  26 , and opposed top and bottom faces  28  and  30 , respectively. The film  22  can be a polymer film, for example, polyethylene terephthalate, oriented polypropylene (e.g., biaxially oriented polypropylene), oriented polyamides, oriented polyvinyl chloride, polystyrene, polycarbonate, polyethylene, polyacrylonitrile, polyolefin and polyimide films. The film  22  can be transparent. Additionally, the film  22  can be intrinsically electrically conductive or static dissipative. Longitudinally extending tear enabling features  32  and  34  and longitudinally extending recesses  36  and  38  are located relative to the bottom face  30  of the film  22 . The tear enabling features  32  and  34  are spaced apart, and a central portion  40  of the film  22  is defined therebetween. A top coating  42  is optionally provided along top face  28  of film  22 . The top coating  42  can include a static dissipative (SD) coating, LAB (i.e., an adhesive release coating), an anti-reflective or glare-reducing coating, and other coatings and combinations of coatings. A bottom coating  44  is also optionally provided along the bottom face  30  of the film  22 , which can be a SD coating or other type of coating and can be at least partially blended with the film  22 . Longitudinally disposed adhesive stripes  46  and  48  are provided along the recesses  36  and  38 .  
         [0025]     The recesses  36  and  38  are located at the longitudinal edges  24  and  26 , respectively, of the film  22 . The recesses  36  and  38  are each open facing the bottom face  30  and longitudinal edges  24  and  26 , respectively, of the film  22 . Alternatively, recesses may be formed on both surfaces of the cover tape. This feature would be useful, for example, if the thicknesses of the adhesive stripes are greater than depth D R , because it would facilitate winding of the cover tape.  
         [0026]     In the embodiment shown in  FIG. 1 , a bottom portion  50  and a side portion  52  define each of the recesses  36  and  38 . The adhesive stripes  46  and  48  can be disposed on the bottom portions  50  of the recesses  36  and  38 , respectively. The bottom portions  50  of the recesses  36  and  38  can have microtexture (not shown in  FIG. 1 ) for better adhering the adhesive stripes  46  and  48  to the film  22 . It should be recognized that other recess shapes can be utilized, so long as the recesses  36  and  38  are open facing an adjacent elongate edge  24  or  26  of the film  22  and the bottom face  30  of the film  22 .  
         [0027]     The film  22 , including recesses  36  and  38  and any microtextures, can be formed using processes such as scoring, extrusion, calendaring, micro-replication, laser ablation, ultrasound, die cutting, chemical etching, and stripping. In further embodiments, the recesses  36  and  38  can be formed using different processes. Moreover, the film  22  can be formed using a film that can fracture or delaminates along a centerline (i.e., a line halfway between the top and bottom faces  28  and  30  of the film  22 ), and separation lines can be cut from the top and bottom to the centerline in order to form the recesses. As illustrated in  FIG. 11A , the fracture or delamination centerline can be established, for example, by laminating or co-extruding two layers of different material  25 ,  27  that have a weak interface. Multiple cover tapes  20  can be formed from a single film web of the two layer material by cutting multiple separation lines across the width of the sheet. Separation lines in one layer will be a width W O  apart. These separation lines will form opposed longitudinal edges  24  and  26  of each adjacent cover tape  20 . Separation lines in the second layer will be spaced away from the separation lines in the first layer by a width W R . These separation lines will form side portions  52  of each adjacent cover tape, which side portions are a width W I  apart. The portion of the second layer opposite the separation line in the first layer will be scrap material  29 . After the separation lines are cut, tapes  20  are formed by separating sections of film  22  along edges  24  and  26 , side portion  52 , and fracture line  31 . Fracture line  31  forms the interior side of scrap material  29 .  
         [0028]     As shown in  FIG. 11B , to avoid having this scrap material, a different process may be used. In this case, both the top and bottom layers of the film web are made of the same material  25  with a thin layer of a different material  27  between these layers to allow for fracture or delamination. Preferably, the cohesive strength of material  27  is less than the adhesive strength between materials  25  and  27 . Because the top and bottom layer materials are the same, both layers may form the wider and narrower portion of the cover tape. (This method could also be used with the top and bottom layers being different materials, but is particularly useful when it is desirable to have the top and bottom layers made of the same material.) Accordingly, adjacent cover tapes may be arranged adjacent each other top-to-bottom (i.e., arranged at a 180° angle relative to each other). Therefore, each separation line in a layer will form a longitudinal edge  24  or  26  of one cover tape and will also form side portion  52  of an adjacent tape. In other words, separation lines on each of the layers will alternately be separated by a width of W O  and a width of W I . In the relation of one layer to another, the distances between separation lines will alternate in opposite orders such that a width W O  in one layer  25  will be paired with a width W I  in the other layer  25 . After the separation lines are cut, tapes  20  are formed by separating sections of film  22  along edges  24 / 52 ,  26 / 52  and fracture line  33 .  
         [0029]     The adhesive stripes  46  and  48  on bottom portion  50  of recesses  36  and  38  can be, for instance, pressure sensitive adhesives (PSAs), heat activated and microencapsulated adhesives. The adhesive stripes  46  and  48  can have thicknesses greater than, less than or equal to a depth D R  of the recessed areas  36  and  38 . Typically, the thickness is less than or equal to depth D R . The adhesive stripes  46  and  48  have widths equal to or less than widths W R  of the recessed areas  36  and  38 . Having widths less than widths D R  of recessed areas  36  and  38  provides substantially adhesive-free zones longitudinally extending along the bottom portions  50  of the recesses  36  and  38  on either side of each of the adhesive stripes  46  and  48  when the cover tape  20  is not applied to a surface (i.e., is not under tension).  
         [0030]     The tear enabling features  32  and  34  are located relative to the bottom face  30  of the film  22 , and can be located adjacent the recesses  36  and  38  at the side portions  52  thereof. However, in further embodiments, the tear enabling features  32  and  34  can be located nearly anywhere along the top face  28 , bottom face  30 , or both faces of the film  22 , so long as they are each spaced from the longitudinal edges  24  and  26  of the film  22 . As shown in  FIG. 1 , the tear enabling features  32  and  34  are continuous scoring lines that extend longitudinally along film  22 . Such scoring lines can be formed by cutting into the film  22  (e.g., with lasers, die cutters, and blades, for instance, according to the blade scoring procedure described below). In further embodiments, the tear enabling features  32  and  34  can be weakened regions of the film  22  (e.g., thinner regions, microperforations, etc.), a transition between two materials (e.g., a first material comprises central portion  40  of the film  22  and a second material comprises the region of the film  22  between the bottom portions  50  of the recesses  36  and  38  and the top face  28 ), or other structures that facilitate tearing.  
         [0031]     In one embodiment, provided by way of example and not limitation, the cover tape  20  can have the following dimensions. An overall width W O  of the film  22  (measured between elongate edges  24  and  26 ) is about 1 inch (2.54 cm). A thickness T of the film  22  is about 2 mil (0.0254 mm) (measured at the thickest portion of the central region  40  of the film  22 ). The recesses  36  and  38  each have a width W R  of about 0.0393701 inch (1 mm) and a depth D R  of about 0.5 mil (0.0127 mm). The tear enabling features  32  and  34  are score lines each having a depth of about 1.5 mil (0.0381 mm) (measured from the bottom face  30  of the film  22 ). It should be recognized that dimensions of the cover tape  20  can vary, as desired. For instance, a width of the central portion  40  of the film  22  can be selected such that it is at least as wide as the pockets of a carrier tape with which the cover tape  20  is used.  
         [0032]      FIG. 2  is a cross-sectional schematic view of another embodiment of a cover tape  80  according to the present invention. The cover tape  80  shown in  FIG. 2  is generally similar to the cover tape  20  shown and described with respect to  FIG. 1 . The cover tape  80  of  FIG. 2  further includes coatings  82  and  84  on elongate edges  24  and  26 , respectively of the film  22 . The coatings  82  and  84  can be LAB coatings in order to reduce the possibility of adhesive becoming attached to the elongate edges  24  and  26 , and therefore reduce the possibility of undesired stickiness, contamination, and other problems associated with exposed adhesives.  
         [0033]      FIG. 3  is a cross-sectional schematic view of another embodiment of a cover tape  90  according to the present invention. The cover tape  90  shown in  FIG. 3  is generally similar to the cover tape  20  shown and described with respect to  FIG. 1 . The cover tape  90  of  FIG. 3  further includes outer recess coatings  92  and  94  and inner recess coatings  96  and  98 . The outer recess coatings  92  and  94  are each located on the bottom portions  50  of the recesses  36  and  38 , adjacent to the adhesive stripes  46  and  48  and toward the elongate edges  24  and  26  of the film  22 . The inner recess coatings  96  and  98  are each located on the bottom portions  50  of the recesses  36  and  38 , adjacent to the adhesive stripes  46  and  48  and toward the side portions  52  of the recesses  36  and  38 . Coatings  92 ,  94 ,  96  and  98  can be, for example, LAB coatings or other tack-free materials that can help prevent undesired contact with adhesives by more positively constraining the adhesive stripes  46  and  48  within the recesses  36  and  38 .  
         [0034]      FIG. 4A  is a cross-sectional schematic view of a further embodiment of a cover tape  100 . The cover tape  100  is generally similar to cover tape  20 ; however, the film  22  includes a first material  104  and a second material  106 . With cover tape  100 , the second material  106  is located at (i.e., above) the recesses  36  and  38  and extends from elongate edges  24  or  26  to material interfaces  108 . The central portion  40  of the film  22  is defined between material interfaces  108 .  
         [0035]     The material interfaces  108  exhibit weaker bonding or connection strength than internal bonding or cohesion of either the first material  104  or the second material  106 . The relative weakness of the material interfaces  108  facilitates substantially consistent and uniform tearing, that is, the separation of the first material  104  and the second material  106  at the material interfaces  108 . Thus, the material interfaces  108  can form tear enabling features.  
         [0036]     The first and second materials  104  and  106  can generally be selected from the same types of materials discussed with respect to  FIGS. 1-3  above. In some embodiments the first material  104  can be weaker than the second material  106 , or vice versa. In other words, one material can have weaker internal cohesive or bonding properties than the other. Moreover, the central portion  40  of the film  22  can be transparent and have high optical clarity.  
         [0037]     The films  22  of cover tapes  100  can be fabricated using processes such as co-extrusion and profile extrusion. With co-extrusion, the first and second materials  104  and  106  are extruded together in a desired arrangement. With profile extrusion, the first and second materials  104  and  106  are extruded individually in desired shapes and are joined while still molten after the initial individual extrusion process. Fabrication may result is some negligible intermingling of the first and second materials  104  and  106  at their interface (e.g., at interface  108  in  FIG. 4A ). One advantage of this embodiment is that the tear enabling features do not require scoring.  
         [0038]      FIG. 4B  is a cross-sectional schematic view of another embodiment of a cover tape  102 . The cover tape  102  is generally similar to cover tape  100 , and the film  22  includes a first material  104  and a second material  106 . With cover tape  102 , the second material  106  is disposed in elongate bands  110  and  112  positioned near side portions  52  of the recesses  36  and  38 , with the first material  104  disposed on either side of bands  110  and  112  of the second material  106 . The central portion  40  of the film  22  is defined between the bands  110  and  112  of the second material  106 .  
         [0039]     The second material  106  is generally weaker than the first material  104 . In other words, the second material  106  has weaker internal cohesive or bonding properties than does the first material  104 . This facilitates consistent and uniform tearing of the film  22  within the bands  110  and  112  of the second material  106 . The bands  110  and  112  thus constitute tear enabling features. In some embodiments, the first material  104  can resist tearing. The second material  106  can comprise a different and weaker form of the type of material as the first material  104 , or can be an entirely different type of material. The first and second materials can generally be selected from the same types of materials discussed with respect to  FIGS. 1-3  above. In addition, the weaker second material  106  can be made of ethylene vinyl acetate (EVA). One advantage of this embodiment is that the tear enabling features do not require scoring.  
         [0040]      FIG. 5  is a cross-sectional schematic view of the cover tape  20  of  FIG. 1  after heat and pressure have been applied. In use, the cover tape  20  may be placed in contact with a surface (e.g., wound upon itself) such that tensile and compressive forces act on the tape  20 . Heat and pressure can cause portions of the film  22  near the recesses  36  and  38  to deflect slightly. Heat and pressure can also cause the adhesive stripes  46  and  48  to deform and migrate. More particularly, heat and pressure can cause the adhesive stripes  46  and  48  to change from first shapes  46 A and  48 A to second shapes  46 B and  48 B. First shapes  46 A and  48 A have a generally greater thickness and generally lesser width than second shapes  46 B and  48 B. Nonetheless, even after such deformation, the adhesive stripes  46  and  48  are substantially contained within recesses  36  and  38  despite the presence of pressure and heat. In the second shapes  46 B and  48 B, the adhesive stripes  46  and  48  are generally spaced from side walls  52  of recesses  36  and  38 , and spaced from the elongate edges  24  and  26  of the film  22 . By substantially containing the adhesive stripes  46  and  48  within the recesses  36  and  38  (even when deformed by heat and/or pressure), the cover tape  20  can be securely adhered to a desired location without undesired exposure of adhesive or adhesion in undesired locations. It should be noted that the features of the recesses  36  and  38  are not limited to the particular embodiment of cover tape shown in  FIG. 5 .  
         [0041]     It is possible to place cover tape according to the present invention in the form of a roll.  FIG. 6  is a cross-sectional schematic side view of a portion of a roll  120  of cover tape  20 . The cover tape  20  is wound upon itself on a core  122  (e.g., a substantially cylindrical cardboard core). In this configuration, the top face  28  of the cover tape  20  is substantially smooth and flat, and the roll  120  is generally stable. In addition, sides  124  of the roll  120  are generally tack-free, as adhesive generally does not protrude from the cover tape  20  along the sides  124  of the roll  120  (adhesive is spaced from the side edges of the tape within the recesses). The adhesive stripes  46  and  48  can releasably adhere to the top coating  42  of the cover tape  20 .  
         [0042]     Cover tape can be placed in a roll (e.g., the roll  120  of  FIG. 6 ) after it has been fabricated and prior to being adhered to a carrier tape. Placing the cover tape in a roll facilitates storage and transportation, as well as automated handling of the cover tape. Coating materials on the top face of the cover tape can facilitate peeling portions of the cover tape away from the roll.  
         [0043]     Cover tape can be used in a carrier tape/cover tape system.  FIG. 7  is a perspective view of a carrier tape/cover tape system  130  that includes a carrier tape  132  and cover tape  20 . The carrier tape  132  has a pair of opposed elongate lip portions  134 , and one or more pockets  136 . Components  138 , such as electronic components, can be placed in the pockets  136 . After the components  138  have been placed in the pockets  136  of carrier tape  132 , as desired, cover tape  20  can be adhered to elongate lip portions  134  in order to cover the pockets  136  and contain the components  138  between the carrier tape  132  and the cover tape  20 . The cover tape  20  can be dispensed from a roll.  
         [0044]     In order to expose and remove the components  138 , a portion of the cover tape  20  is separated from the system  130 . As shown in  FIG. 7 , the central portion  40  of the cover tape  20 , defined between tear enabling features  32  and  34 , is torn away. Outer portions  140  of cover tape  20  remain adhered to carrier tape  132  after the central portion  40  of the cover tape  20  is torn away. After being torn away, the central portion  40  of the cover tape  20  can be wound into a roll  142  for discard or recycling.  
         [0045]     The central portion  40  of the cover tape  20  is separated at the tear enabling features  32  and  34  (e.g., score lines in the embodiments shown and described with respect to  FIGS. 1-3 ). In other embodiments, separation can occur at material interfaces (e.g., material interfaces  108  as shown and described with respect to  FIG. 4A ), at bands of weaker material (e.g., bands  110  and  112  of the second material  106  as shown and described with respect to  FIG. 4B ), or other locations depending on the type and location of tear enabling features.  
         [0046]     It is desirable to have a substantially uniform tear force when tearing away a portion of the cover tape. Although lasers or blades can be used to create scoring lines, making multiple precise scoring lines capable of less than 0.001 inch (0.0254 mm) in variation can be expensive with lasers, and is nearly impossible with known uses of blades that are hindered by variations in blade cutting edge alignment.  
         [0047]     In order to achieve uniform tearing with cover tapes having scoring lines, it is desired to provide scoring lines with very little variation in depth along the length of the cover tape as well as between distinct scoring lines. Scoring lines with substantially uniform depth can be simply and efficiently formed in a film web using the method and apparatus described below. Scoring lines are generally formed in a film web after the film has been formed with recesses; however, scoring lines can be performed at other stages of a cover tape fabrication process. For example, one possible manufacturing process includes forming a plurality of parallel, laterally spaced apart and longitudinally extending recesses in a large film web. Next, longitudinal scoring lines are formed in the large film web. Then longitudinal adhesive stripes are applied to the recesses of the film (e.g., two spaced apart stripes of adhesive, with one stripe within each recess). Finally, the large film web is cut and separated into a plurality of individual cover tape strips by cutting through each recess between the adhesive bands therein.  
         [0048]      FIG. 8  is a schematic side view of a scoring apparatus  200  that includes web support rollers  202 A,  202 B and  202 C and a blade assembly  204 .  FIG. 9  is a cross-sectional schematic side view of the blade assembly  204 . The blade assembly  204  includes a main structure  206  with a cavity  208  defined along a rear face  210  and a generally-U-shaped opening  212  defined along a front face  214 . The main structure  206  is supported by a pivot  216 . Alignment means  218  (e.g., adjustable micrometer assemblies) are provided in order to provide precise alignment of the scoring apparatus  200  relative to roller  202 B, for instance, to adjust the scoring depth. In order to maintain a substantially constant scoring depth, it is preferable to reduce the impact of variability in geometry of support roller  202 B. This can be achieved by attaching one or more scoring depth control rollers  228  to the main structure  206 . These scoring depth control rollers  228  are in direct contact with the web support roller  202 B and enable the main structure  206  to follow the contour of the web support roller  202 B, which will minimize variations in scoring depth. One or more blades  220  (e.g., conventional flat metallic blades having linear tapered cutting edges in configurations generally resembling that of a single-edged razor blade) are inserted into cavity  208  such that cutting edges  222  of the blades  220  face the front face  214  of the main structure  206  and contact a precision inner surface  224  ( FIG. 9 ) of the cavity  208  that defines a plane. The blades  220  are biased against the precision surface  224 , using biasing means such as ties, springs and bumpers (biasing means not shown in  FIG. 8 ). Generally central portions of the cutting edges  222  of the blades  220  are exposed through the opening  212  in order to permit the blades  220  to cut a film web material that contacts them.  
         [0049]     The main structure  206  of the blade assembly  204  can be formed of any material (e.g., metal, glass, polymers, etc.) such that the precision inner surface  224  resists cutting by the blades  220 . In one embodiment, the main structure  206  is formed of a metallic material that is at least as hard as the blades  220 .  
         [0050]     In operation, an unscored film  22 A passes between the roller  202 B and the blade assembly  204 . The cutting edges  222  of the blades  220  are adjusted with alignment means  218  relative to the roller  202 B, such that desired cutting depths are achieved. It is possible to provide different cutting depths for different blades. For instance, some blades can provide scoring while other blades can simultaneously cut apart individual cover tape strips from an article that includes a plurality of connected cover tape strips. However, cutting to separate individual cover tape strips need not be performed at the same time as scoring.  
         [0051]     After passing the blade assembly  204 , the now scored film  22 B can be moved by the roller  202 C to other locations for further processing, and can be ultimately wound in a roll (e.g., roll  120  as shown and described with respect to  FIG. 6 ).  
         [0052]     It is possible to provide a plurality of score lines in a film simultaneously using the apparatus shown and described with respect to  FIGS. 8 and 9 .  FIG. 10  is a schematic back view of the blade assembly  204 . In  FIG. 10 , the blades have been omitted for clarity. A number of lateral spacers  226  are inserted into the cavity  208  of the blade assembly  204 . Gaps are formed between adjacent spacers such that a blade can be inserted into the gap. The spacers provide for alignment of the blades across a width of a film to be scored. In addition, the spacers provide support to the blades, which can be thin, in order to increase rigidity of the blades and promote the formation of straight and uniform scoring lines. The number, size, and arrangement of the spacers  226  will vary according to the desired scoring pattern. The spacers  226  can be formed of a metallic or polymer material.  
         [0053]     In further embodiments, the spacers  226  can be integrally formed with the main structure  206  of the blade assembly  204 . In such embodiments, a blade alignment plane can be collectively defined by the plurality of precision surfaces  224  formed relative to each gap.  
         [0054]     In light of the discussion above, numerous advantages and benefits of the present invention should be recognized. One advantage of the cover tape according to the present invention is that it has a very uniform removal force of the central portion of the tape, which reduces the risk of miss-picks during storage and transportation operation due to parts or components “jumping” out of the carrier pocket of the carrier tape. In addition, the cover tape can be made more cost effective by using adhesive stripes while resolving the winding issues normally encountered with adhesive stripe-coated tapes (e.g., unstable rolls with sagging problems). In addition, the cover tape of the present invention also reduces a risk of adhesive build-up on equipment due to adhesive “squeeze-out” by keeping the adhesive substantially contained in the recesses before and after tearing of the middle portion of the tape. It also has substantially tack-free side edges when wound in a roll format, which reduces a risk of contamination when the roll of cover tape is laid on a table or other surface. Further, while forming the cover tape, no cutting through adhesive is required, which may lead to more effective processing by avoiding adhesive build-up on cutting equipment.  
         [0055]     The method and apparatus for scoring the film also present numerous advantages. Scoring can be accomplished, simply, efficiently, and in a cost-effective manner. The scoring apparatus of the present invention permits substantially uniforms scoring depth to be provided, with relatively little variation in scoring depth. By using conventional blades (e.g., blades resembling single-edged razor blades) in the manner of the present invention, the scoring apparatus is relatively simple, and the blades and apparatus are relatively inexpensive. Moreover, by aligning the blades directly at their respective cutting edges, rather than using blade reference features (e.g., notches and holes) that are spaced from the cutting edges, undesired variation in cutting or scoring depth due to individual variations in the blades can be reduced.  
         [0056]     Although the present invention has been described with reference to several alternative embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. For instance, various types of tear enabling features can be used according to the present invention, and those tear enabling features can have various arrangements.