Abstract:
A tape carrier includes: a base film with insulating property; a wiring pattern provided on the base film within a product region, the product region being demarcated by a cutting line so as to divide the tape carrier into individual products by cutting along the tape carrier along the cut line; and a solder resist provided on the base film so as to cover the wiring pattern. The solder resist protrudes outward from within the product region.

Description:
The entire disclosure of Japanese Patent Application No. 2007-088237, filed Mar. 29, 2007 is expressly incorporated by reference herein. 
   BACKGROUND 
   1. Technical Field 
   The present invention relates to a tape carrier, a semiconductor device, and a method for manufacturing semiconductor device. 
   2. Related Art 
   Size and weight reduction of electric products such as liquid crystal panels and mobile terminals is advancing. These electric products include integrated circuit devices, and these devices packaged inside cases are generally mounted on insulating film substrates that can be bended easily, for instance, by hand. These film substrates are formed with, for instance, polyimide, and are called tape carriers or flexible substrates. Packaged products including integrated circuit devices mounted on such tape carriers are called tape carrier packages (TCP), chip on films (COF), or flexible print circuits (FPC). Refer to JP-A-2004-235322 and JP-A-2000-269249 for examples. 
     FIGS. 4A and 4B  are plan views showing an example of a structure of a tape carrier  200  according to an example of a related art.  FIG. 4A  illustrates a status before stamping the long tape carrier  200  along cut lines  251  which are the outlines of the final product regions. The tape carrier  200  includes an insulating base film  201 , inner and outer leads (hereafter referred to as “leads”)  203  provided thereon, and solder resists  205  which mainly cover the inner leads. 
   Each of the solder resists  205  covering the leads  203  is formed with resin by coating a base film  201  in a state before forming the leads  203 , using dispensing or screen printing, and thereafter curing it (i.e. carrying out heat treatment). Here, since the solder resist  205  before being cured is in a liquid state with a certain degree of viscosity, the edge of the fluid rises by the effect of the surface tension during the steps of coating to curing. In other words, as shown in  FIG. 4B , a part in each of the solder resists  205 , positioned inward from the edge thereof by approximately 0.5 to 0.8 mm, is thicker compared to the center part, resulting in a problem of unevenness in film thickness. Since the solder resists  205  are translucent, the uneven film thickness tends to cause color irregularities, i.e., defect in the outer appearance. 
   Moreover, as shown in  FIG. 5 , subsequent to packaging an integrated circuit (IC) device  211  and stamping the tape carrier  200  along the cut lines  251 , the tape carrier  200  is bended at a bending line  261 . At this time, a thick film portion  205   a  in each of the solder resists  205  behaves like a core, preventing a smooth bending. In particular, if the thicknesses of the thick solder resist portions  205   a  are uneven, the tape carrier tends to bend at a portion in the thick solder resist portions  205   a  which are thinner and weaker. This results in the irregularities of bending, i.e., defect in bending. 
   SUMMARY 
   An advantage of some aspects of the invention is to provide: a tape carrier that improves the properties of outer appearance and of bending; a semiconductor device; and a method for manufacturing the semiconductor device. 
   According to a first advantage of the invention, a tape carrier includes a base film with insulating property; a wiring pattern provided on the base film within a product region, the product region being demarcated by a cutting line so as to divide the tape carrier into individual products by cutting the tape carrier along the cut line; and a solder resist provided on the base film so as to cover the wiring pattern. The solder resist protrudes outward from within the product region. 
   With this structure, the tape carrier can be bended easily with less resistance, by arranging the bending line which is the bending axis so as to cover “a portion protruding outward from inside the product region” of the solder resist in plan view, at the time of bending and packaging the tape carrier into a case of an electric product after the tape carrier is divided into individual products. Moreover, compared to the common tape carrier, there are less thick film portions in the solder resist, improving the outer appearance. 
   In this case, the product region includes a bendable region having a bending line as an axis; and the solder resist is formed to protrude outward from within the product region, so as to overlap with the bending line in plan view, 
   With this structure, the core (i.e. the thick film portion of the solder resist) which is resistant to the bending of the tape carrier after cutting the tape carrier is made smaller or is not present. Therefore, the tape carrier is bended easily. Moreover, this improves the uniformity in the film thickness of the solder resists in the product region, thereby also improving the evenness in a stress distribution of the solder resists during the bending. Consequently, fluctuation in the manner of bending the tape carrier is reduced. 
   In this case, an edge of the solder resist is pulled out to the outside of the product region so that a thick film portion of the solder resist overlapping with the bending line in plan view is present only on the outside of the product region, and not on the cutting line nor inside the product region. 
   With this structure, when bending a tape carrier after dividing it, the core part (i.e. the thick film portion of the solder resist) which becomes resistant to bending is eliminated almost completely. Therefore, the tape carrier is bended easily enough, and the fluctuation in the manner of bending the tape carrier is sufficiently reduced. 
   According to a second aspect of the invention, a method for manufacturing a semiconductor device includes: installing an integrated circuit device on the tape carrier according to the first aspect of the invention; and cutting the tape carrier along the cutting line so as to divide the tape carrier into individual products. 
   The tape carrier according to the first aspect of the invention is applied in this method, and thus it is possible to provide the semiconductor device which is easy to bend, with less fluctuation in the manner of bending the tape carrier when packaging it into a case of an electric product. 
   According to a third aspect of the invention, a semiconductor device includes: a base film with insulating property; a wiring pattern provided on the base film; and a solder resist provided on the base film so as to cover the wiring pattern. The base film includes a bendable region having a bending line as an axis. A thick film portion of the solder resist is present on the base film in a region not including the bendable region, the thick film portion of the solder resist being not present on the base film in the bendable region. 
   With this structure, since the thick film portion of the solder resist functions as a resistance against bending (i.e. a core), the strength of the tape carrier is improved in a region which is not a bendable region (i.e. in a region that should not be bended). 
   In this case, the thick film portion of the solder resist present in the area excluding the bendable region is formed to be parallel to the bending line. 
   With this structure, the resistance against the bending of the tape carrier is reduced in the direction for bending, and improved in the direction that should not be bended. 
   According to a fourth aspect of the invention, a semiconductor device includes: a base film with insulating property, the base film including a bending region bended at a bending line; a wiring pattern provided on the base film; and a solder resist provided on the base film so as to cover the wiring pattern, the solder resist having a first portion and a second portion, the first portion being provided on the bending region of the base film, the second portion being provided on the base film excluding the bending region, a thickness of the first portion of the solder resist being even, the second portion of the solder resist having a portion thicker than the first portion. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements. 
       FIG. 1  is a plan view illustrating an example of a structure of a tape carrier according to an aspect of the invention. 
       FIG. 2  is a drawing of the tape carrier after stamping (dividing). 
       FIG. 3  is a drawing illustrating another example of the tape carrier. 
       FIGS. 4A and 4B  are drawings illustrating an example of a structure of a common tape carrier. 
       FIG. 5  is a drawing of the tape carrier after stamping (dividing). 
   

   DESCRIPTION OF EXEMPLARY EMBODIMENTS 
   Embodiments of the invention will now be described with references to the accompanying drawings. 
     FIGS. 1 and 2  are plan views illustrating an example of a structure of a tape carrier  100  according to one embodiment of the invention. Specifically,  FIG. 1  indicates a state of the tape carrier  100  before stamping the tape carrier along cut lines  51  that demarcate a production region. The double dotted lines in  FIG. 1  are the cut lines  51  and regions surrounded thereby are product regions. Moreover,  FIG. 2  indicates the tape carrier  100  divided into individual products by stamping the tape carrier  100  along the cut lines  51 . 
   As shown in  FIG. 1 , the tape carrier  100  includes, in a state prior to being stamped, a long base film  1 , sprocket holes  2  provided on a side edge in the longitudinal direction of the base film  1 , inner and outer leads (hereafter referred to as “leads”)  3 , and solder resists  5  coated on the tape carrier  100  so as to cover these leads  3 . The base film  1  is formed with an insulating material such as polyimide, and the leads  3  are formed with metallic thin film such as copper film. As shown in  FIG. 1 , the internal product region includes regions in which IC devices are installed (IC installation regions  53 ), and regions on which resin for sealing the IC devices is coated (resin regions  55 ). 
   When manufacturing a semiconductor device using this tape carrier  100 , an IC device  11  (refer to  FIG. 2 ) is installed in each of the IC installation regions  53 , and thereafter an epoxy resin  12  (refer to  FIG. 2 ) is coated on each of the resin regions  55 , so as to seal the IC device  11  with resin. Subsequently, the tape carrier  100  is stamped along the cut lines  51  using a die, so as to be divided into individual products. 
   This tape carrier  100  includes, similar to the related art described above, a bendable region (bending region) for storing the divided tape carrier into a case of electric product and the like. In this embodiment, this bending region includes an improvement in a structure that the solder resists  5  protrude outward from within the product region to the outside along the bending line  61  described above. 
   In other words, the solder resists  5  overlapping with the bending region are formed protruding outward from the two sides of the product region. Each distance L protruding outward from each of the two sides of the product region is sufficiently long enough for each of the thick film portions  5   a  at the edge of the solder resists  5  to be formed, by curing, only in a region outside of the product region which overlaps with the bending region, and not inside of the product region. For instance, according to an experiment carried out by the inventor, the thick film portions  5   a  were completely excluded from the bending region after dividing the tape carrier, by setting the distance L to be equal to or greater than 0.8 mm. The optimal value of the distance L changes in accordance with the type of the solder resists  5  and the condition of curing. Therefore, when embodying the aspects of the invention, it is preferable that the optimal value of the distance L is obtained by carrying out experiments for various types of solder resists in various curing conditions. 
   As described, according to the embodiment, the bending region does not include the core parts (i.e. the thick film portions  5   a  of the solder resists  5 ) which become resistant to the bending of the already-divided tape carrier  100 . Therefore, the tape carrier  100  is bended easily. Moreover, this improves the uniformity of the film thickness of the solder resists  5  in the product region, thereby reducing the irregularities of the film thicknesses. Further, improving the evenness of stress distribution during the bending of the solder resists  5   a  reduces the difference in how the tape carrier  100  is bended. 
   According to the embodiment, the thick film portions  5   a  of the solder resists  5  are formed, by curing, also in the product regions positioned away from the bending region as shown in  FIG. 1 . The thick film portions  5   a  deviated from this bending region remain on the base film  1  as is, after dividing the tape carrier  100  as shown in  FIG. 2 . Here, the thick film portions  5   a  positioned away from this bending region are parallel to the bending line  61 . Therefore, when a force works to bend the tape carrier  100  in a direction orthogonal to the bending line after the tape carrier  100  is divided, the thick film portions  5   a  function as resisting bodies (i.e. cores) against bending. 
   As described, the resisting force of the tape carrier  100  against bending can be weakened in the direction of bending, and strengthened in the direction in which the bending should be avoided, since the thick film portions  5   a  remain parallel to the bending line. 
   In the first embodiment, each of the cut lines  51  correspond to ‘a cutting line’ according to the aspects of the present invention, and each of the leads  3  correspond to ‘a wiring pattern’ according to the aspects of the present invention. 
   In the above embodiment, the solder resists  5  are formed on the base film  1  before stamping, so as to space the two adjacent production regions, as shown in  FIG. 1 . However, the alignment of the solder resists  5  in plan view is not limited thereto. For instance, as shown in  FIG. 3 , the solder resists  5  may be formed continuously without spaces between the product regions, along the longitudinal direction of the base film  1 . The thick film portions  5   a  of the solder resists  5  are not formed in the bending region in this structure. Therefore, an advantage similar to that of the tape carrier  100  shown in  FIGS. 1 and 2  is obtained. 
   In the above embodiment, as shown in  FIG. 1 , the IC installation regions  53  are aligned along the longitudinal direction of the base film  1 , and the leads  3  are aligned in a direction orthogonal to the longitudinal direction of the base film  1 . In other words, the product regions are aligned in a direction orthogonal to the longitudinal direction of the base film  1 . However, the IC installation regions  53  may be extended to a direction orthogonal to the longitudinal direction of the base film  1 , and the leads  3  may be aligned in a longitudinal direction of the base film  1 . In other words, the product regions are aligned along the longitudinal direction of the base film  1 .