Abstract:
A printing circuit board includes: an insulator having an upper surface, a lower surface and an opening formed in the lower surface, and a trace having an upper surface, a lower surface and a side edge and received in said insulator. The upper surface of said trace is exposed out of the insulator and a portion of the lower surface of said trace is exposed by said opening for external connection.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention generally relates to a Printing Circuit Board, and more particularly related to a PCB which is comprised of an insulator and a trace embedded therein, wherein both the upper surface of trace and a portion of the lower surface of trace exposed to the atmosphere for connecting external substance. 
     2. Description of the Related Art 
     Nowadays, both science and technology are developing rapidly, meanwhile, electrical devices are designed for thinner, wider application, lower cost, and better reliability, wherein in order to achieve above objects, the manufacturers keep on developing it. 
       FIG. 9  shows a conventional PCB  52  comprised of: an insulator  40  which is made of FR-4 or BT (Bismaleimide Triazine) or epoxy etc. having a blind via  44 , an upper surface  41  and a lower surface  42 ; said blind via  44  is for accommodating a portion of trace  7 A; a ball pad  7 B which is made of metal such as copper for external connection (e.g. solder ball), said ball pad  7 B having a side edge  7 B 3 , an upper surface  7 B 1 , and a lower surface  7 B 2 , wherein both said side edge  7 B 3  and a portion of lower surface  7 B 2  of trace  7 A encapsulated by said insulator  40 , wherein another portion of lower surface  7 B 2  exposed to blind via  44  for being coupled with said trace  7 A, said upper surface  7 B 1  of ball pad  7 B exposed out of the lower surface  42  of insulator  40  for external connection (i.e. said upper surface  7 B 1  of ball pad  7 B exposed to atmosphere for external connection); a trace  7 A which is made of metal such as copper for being employed as a path of transmitting electrical current, said trace  7 A having a side edge  7 A 3 , an upper surface  7 A 1  and a lower surface  7 A 2 , wherein said lower surface  7 A 2  coupled with said upper surface  41  of insulator  40 , a portion of trace  7 A accommodated in said blind via  44 , in this manner, said trace  7 A electrically connected to said ball pad  7 B through said blind via  44 ; a solder mask  80  covering both said upper surface  41  of insulator  40  and a portion of said trace  7 A, wherein another portion of said trace  7 A being exposed to the atmosphere for external connection; and a plurality of conductive layers  90  which are made of nickel, gold, silver or the like are valuable and expensive, said conductive layers  90  coupled with said upper surface  7 B 1  of ball pad  7 B and the portion of trace  7 A exposed to atmosphere (i.e. both said another portion of upper surface  7 A 1  and said side edge  7 A 3 ) respectively; accordingly, (1). The path of transmitting electrical current from the upper surface  41  of insulator  40  to the lower surface  42  of insulator  40  of said conventional PCB  52  is from the upper surface  7 A 1  of trace  7 A through said blind via  44  of insulator  40  to said upper surface  7 B 1  of ball pad  7 B; (2). said solder mask  80  having a thickness Ta which is comprised of a thickness T 81  and a thickness T 82 , wherein said thickness T 81  is the distance between the upper surface  7 A 1  of trace  7 A and the upper surface  41  of insulator  40 , said thickness T 82  is the distance between the upper surface of said solder mask  80  and the upper surface  7 A 1  of trace  7 A, consequently, according to the features of conventional PCB  52  mentioned above, the thickness T 52  which is included the thickness T 4  of insulator  40  and thickness Ta becomes thicker, in this manner, it is not convenient for said conventional PCB  52  to be used in the electronic industries; (3). said side edge  7 A 3  of trace  7 A also needs to be covered with said conductive layer  90 , in this manner, more material needs to be used, then the cost for manufacturing said conventional PCB  52  becomes higher; and (4). Due to there is not any solder mask coupled with the lower surface  42  of insulator  40 , then said ball pad  7 B can&#39;t be employed as a path of transmitting electrical current but be employed as a terminal for external connection (e.g. solder ball) exclusively, in this manner, said ball pad  7 B enables not to be layout on said lower surface  42  of insulator  40  freely, moreover, said ball pad  7 B is oxidized and damaged easily without solder mask protecting; meanwhile, due to it is difficult for the width “W” of ball pad  7 B to be changed, when said ball pad  7 B coupled with said lower surface  42  of insulator  40 , then it is restricted for said conventional PCB  52  to be used in electronic industry; For example: in case that the volume of solder ball (not shown) is unchanged, and the height of solder ball is needed to be decreased (i.e. said width “W” of ball pad  7 B is needed to become wider for reaching the demand mentioned above), nevertheless, due to said width “W” of ball pad  7 B can&#39;t be changed to become wider for reaching said demand when said ball pad  7 B coupled with said lower surface  42  of insulator  40 , then the height of solder ball  7 B can&#39;t be reached to the qualification of electrical device(s) such as PBGA or CSP, in this manner, said conventional PCB  52  enables not to be invited to said electrical devices, as this result, the application of said conventional PCB  52  is restricted. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the invention to solve the mentioned-above problems, in accordance with the invention, the PCB includes an insulator and a plurality of traces, wherein said traces are embedded in the insulator, and wherein both the upper surface and a portion of the lower surface of said trace exposed out of said insulator, in this manner, both said upper surface and said portion of the lower surface of said trace exposed to atmosphere for connecting external substance, nevertheless, another portion of the lower surface of trace encapsulated by said insulator, in this manner, it is not necessary for said lower surface of trace to be coupled with a solder mask which is for protecting said lower surface of trace, as this result, the advantages of said PCB includes: (1). the cost is saved; (2). the thickness is thinner; (3). the reliability of said PCB is enhanced; (4). the blind via can be omitted; and (5). it is more convenient for the PCB to be used in electronic industries in accordance with the present invention, moreover, the trace of PCB can further include an extending portion. 
     The aforementioned and further objects of the present invention will more adequately appeared from the detailed description, accompanying drawings and appended claims as follow. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a cross-sectional view of PCB in accordance with the present invention, wherein a trace embedded in the insulator. 
         FIG. 2  shows a cross-sectional view of PCB in accordance with the present invention, wherein the trace having a second side edge. 
         FIG. 3  shows a cross-sectional view of PCB in accordance with the present invention, wherein an another trace coupled with the lower surface of insulator. 
         FIG. 4  shows a cross-sectional view of PCB in accordance with the present invention, wherein a solder mask coupled with the lower surface of insulator. 
         FIG. 5-6  show cross-sectional views of PCB in accordance with the present invention, wherein the upper surface protruded the upper surface of insulator and exposed to the atmosphere. 
         FIG. 7  shows a cross-sectional view of PCB in accordance with the present invention, wherein the trace having an extending portion. 
         FIG. 8  shows a cross-sectional view of package, wherein the PCB in accordance with the present invention involved in said package is coupled with an encapsulant, a chip, conductive wire(s) and solder ball. 
         FIG. 9  shows a cross-sectional view of PCB according to a prior art. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Embodiments of the present invention will be explained with reference to the drawings as follow. 
       FIG. 1  shows a PCB  50  comprising: an insulator  40  is made of FR-4, BT, epoxy or the like, said insulator  40  having an upper surface  41 , a lower surface  42  and a recess  48 ; a trace  70  is made of copper, copper alloy, nickel, aluminum or the like, said trace  70  having an upper surface  71 , a lower surface  72  and a side edge  73 , wherein said lower surface  72  of trace  70  consists of a first lower surface  721  and a second lower surface  722 , both said first lower surface  721  and said second lower surface  722  are co-planar, said trace  70  embedded in said insulator  40 , in this manner, said trace  70  is encapsulated by said insulator  40 , wherein both said side edge  73  and said first lower surface  721  of trace  70  are encapsulated by said insulator  40 , wherein said upper surface  71  of trace  70  exposed to atmosphere (i.e. said upper surface  71  of trace  70  exposed out of said upper surface  41  of insulator  40 ) for connecting external substance(s), and wherein said second lower surface  722  of trace  70  placed within said recess  48  of insulator  40 , and wherein said second lower surface  722  is the bottom of said recess  48  of insulator  40 , said second lower surface  722  of trace  70  exposed to atmosphere (i.e. said second lower surface  722  of trace  70  exposed out of said lower surface  42  of insulator  40 ) for connecting external substance(s), meanwhile, said first lower surface  721  corresponding to the portion of said upper surface  71  of trace  70  enables to be employed as a path for transmitting electrical current, and furthermore, said second lower surface  722  of trace  70  is employed as a ball pad too (refer to the detailed descriptions of  FIG. 8 ), accordingly, Not only said trace  70  enables to be employed as a path for transmitting electrical current, but said second lower surface  722  of trace  70  enables to be employed as a ball pad; a solder mask  80  covering said upper surface  41  of insulator  40  and a portion of said upper surface  71  of trace  70  for protection, wherein another portion of said upper surface  71  of trace  70  exposed to atmosphere for connecting external substance, wherein said solder mask  80  is optional, and wherein said external substance(s) employed as: solder ball, conductive wire, conductive layer, resistor, capacitor, another trace (refer to the detailed descriptions of  FIG. 3 ) and/or a slot of electrical device (e.g. camera, cell phone); and a plurality of conductive layers  90 , said conductive layers  90  coupled with said upper surface  71  and said second lower surface  722  of trace  70  respectively, wherein the conductive layer  90  coupled with said second lower surface  722  of trace  70  is placed within said recess  48  of insulator  40 , and wherein each upper surface of conductive layer  90  exposed to the atmosphere for connecting to conductive wire, conductive bump, solder ball, resistor and/or capacitor, said conductive layer  90  can be made of either a multi-layered metal or a single metal layer. For example: please, refer to the conductive layer  90  coupled with said second lower surface  722  of trace  70 , In case that (1). said conductive layer  90  is made of a multi-layered metal such as two-layered metal which is comprised of a layer of nickel and a layer of gold (or silver), both said layer of nickel and said layer of gold are stack, wherein the lower surface (not shown) of said layer of nickel is employed as said lower surface of conductive layer  90 , the upper surface (not shown) of said layer of gold is employed as said upper surface of conductive layer  90 , the lower surface of said conductive layer  90  coupled with said second lower surface  722 , in this manner, the upper surface of conductive layer  90  is exposed to atmosphere; and moreover. In case that said conductive layer  90  is made of a three-layered metal which is comprised of a layer of nickel, a layer of palladium and a layer of gold, wherein said layer of nickel, said layer of palladium and said layer of gold are stack, and wherein said layer of palladium is between said layer of nickel and said layer of gold, in this manner, the lower surface (not shown) of said layer of nickel is employed as said lower surface of conductive layer  90 , the upper surface (not shown) of said layer of gold is employed as said upper surface of conductive layer  90 , the lower surface of said conductive layer  90  coupled with said second lower surface  722 , in this manner, the upper surface of conductive layer  90  is exposed to the atmosphere. In addition, due to gold, palladium, and silver are valuable (expensive), as this reason, the smaller area of conductive layer  90  is, the saved the cost is; and (2). In case that said conductive layer  90  is made of a single metal such as a tin (solder), wherein the lower surface (not shown) of said layer of tin is employed as said lower surface of conductive layer  90 , the upper surface (not shown) of said layer of tin is employed as said upper surface of conductive layer  90 , the lower surface of conductive layer  90  coupled with said second lower surface  722 , in this manner, the upper surface of conductive layer  90  is exposed to the atmosphere; Consequently, the advantages of said PCB  50  in accordance with the present invention are: (a). the path of transmitting electrical current of said PCB  50  from the upper surface  41  of insulator  40  to the lower surface  42  of insulator  40  of said PCB  50  is from the upper surface  71  of trace  70  to said second lower surface  722  of trace  70  exclusively, in this manner, the blind via (shown in  FIG. 9 , numeral of “ 44 ”) is omitted; meanwhile, said path of transmitting electrical current of said PCB  50  enables to become shorter, furthermore, the ball pad  7 B (shown in  FIG. 9 ) is substituted by the second lower surface  722  of trace  70 , wherein due to the blind via ( 44 ) is omitted, in this manner, the thickness T 50  of PCB  50  enables to be thinner than the thickness T 52  of conventional PCB  52  (shown in  FIG. 9 ); moreover, due to the trace  70  embedded in the insulator  40 , then it is not necessary for said side edge  73  of trace  70  to be covered with either solder mask  80  or conductive layer  90 , in this manner, Not only the thickness T 8  of solder mask  80  enables to become thinner than the thickness Ta of solder mask  80  of conventional PCB  52  but the cost of said PCB  50  enables to be saved; and (b). it is easy to respond the demand of height of solder ball, due to the width “W” of second lower surface  722  of trace  70  enables to be changed easily, then it is easy for said PCB  50  to reach the height qualification of electrical device, and then it is convenient for said PCB  50  to be used in electronic industry; For example: in case that the volume of solder ball is unchanged, and the height of solder ball is needed to be decreased (i.e. it is necessary for the width of second lower surface  722  of trace  70  to be getting wider than the width “W” (shown in  FIG. 1 ) for reaching the demand mentioned above), wherein due to said “W” of second lower surface  722  can be changed to become wider, then the height of solder ball can be reached to the qualification of electrical device (i.e. when said trace  70  embedded in said insulator  40 , wherein while a wider recess of insulator  40  is formed, and then a wider width of second lower surface  722  is formed too, as this result, said PCB  50  enables to have a wider width of second lower surface  722  of trace  70  to respond the demand mentioned above), in this manner, said PCB  50  enables to be invited to said electrical devices, as this result, the application of said PCB  50  is convenient; In addition, the advantages of said first lower surface  721  of trace  70  is described in  FIG. 8  later. 
       FIG. 2  shows a PCB  55  in accordance with the present invention, said structure of PCB  55  is similar to the structure of PCB  50  shown in  FIG. 1 , the differences between said PCB  55  and said PCB  50  are: (1). the upper surface  71  of trace  70  of PCB  55  is below the upper surface  41  of insulator  40 , in this manner, said upper surface  71  of trace  70  is not co-planar to said upper surface  41  of insulator  40 ; wherein the upper surface  71  of trace  70  enables to be protruding the upper surface  41  of insulator  40  (refer to  FIG. 5  or  FIG. 6 ), said upper surface  71  of trace  70  is not co-planar to said upper surface  41  of insulator  40  either while the upper surface  71  of trace  70  protruding the upper surface  41  of insulator  40 , accordingly, it is optional that the upper surface  71  of trace  70  is below the upper surface  41  of insulator  40 ; and (2). the second lower surface  722  of trace  70  is below the first lower surface  721  of trace  70 , in this manner, said second lower surface  722  of trace  70  is not co-planar to said first lower surface  721  of trace  50 , in this manner, said trace  70  further having a second side edge  732  which is between said first lower surface  721  and said second lower surface  722  of trace  70 , said second side edge  732  of trace  70  placed in said recess  48  of insulator  40  too, Consequently, due to said second side edge  732  of trace  70 , the area that said trace  70  contacted to the conductive layer  90  which is coupled with the second lower surface  722  of trace  70  enables to be increased, then it allows said conductive layer  90  to be not only coupled with the second lower surface  722  but also coupled with said second side edge  732  of trace  70 , in this manner, said conductive layer  90  enables to be coupled with said trace  70  more securely, then it can prevent said conductive layer  90  from peeling off said trace  70 , and then the reliability of said PCB  50  can be enhanced, accordingly, due to said second side edge  732  of trace  70 , in case that either a conductive material such as an another trace (refer to  FIG. 3 ) or an isolative material such as a solder mask (refer to  FIG. 4 ) coupled with said second side edge  732 , the reliability of said PCB  50  can be enhanced; wherein the second lower surface  722  of trace  70  enables to be protruding the first lower surface  721  of trace  70  (not shown), as this result, said second lower surface  722  of trace  70  is not co-planar to said first lower surface  721  of trace  70  either, accordingly, it is optional that the second lower surface  722  of trace  70  is below the first lower surface  721  of trace  70 ; furthermore, either the conductive layer  90  coupled with the upper surface  71  of trace  70  or the conductive layer  90  coupled with the second lower surface  722  (associated with the second side edge  732 ) of trace  70  can be protruding (or below) the upper surface  41  or the lower surface  42  of insulator  40  as required. 
       FIG. 3  shows a PCB  50  in accordance with the present invention, said structure of PCB  50  is similar to the structure of PCB  55  shown in  FIG. 2 , the difference between said PCB  50  and said PCB  55  is: said PCB  50  further comprising an another trace  75  which is coupled with the lower surface  42  of insulator  40 , in this manner, said another trace  75  enables to be lay out on said lower surface  42  of insulator  40  freely, and wherein a portion of said another trace  75  is placed within said recess  48  of insulator  40  and is coupled with both the second lower surface  722  and the second side edge  732  of trace  70 , By means of said second side edge  732  of trace  70 , the area that said another trace  75  contacted to the trace  70  enables to be increased, (i.e. it allows said another trace  75  to be not only coupled with the second lower surface  722  but also coupled with said second side edge  732  of trace  70 ), in this manner, said another trace  75  enables to be coupled with said trace  70  more securely, then it can prevent said another trace  75  from peeling off said trace  70 , and then the reliability of said PCB  50  can be enhanced; In additional, a further another trace(s) (not shown) or an another insulator(s) (not shown) can be coupled with the lower surface  42  of insulator  40 , in this manner, said PCB  55  is employed as a multi-layer PCB. 
       FIG. 4  shows a PCB  50  in accordance with the present invention, said structure of PCB  50  is similar to the structure of PCB  55  (shown in  FIG. 2 ), the differences between said PCB  50  and said PCB  55  are: (1). said PCB  50  further comprising a solder mask  80  which is coupled with the lower surface  42  of insulator  40 , wherein a portion of said solder mask  80  is placed in said recess  48  of insulator  40  and is coupled with both the second lower surface  722  and the second side edge  732  of trace  70 , By means of said second side edge  732  of trace  70 , the area that said solder mask  80  contacted to the trace  70  enables to be increased, (i.e. it allows said solder mask  80  to be not only coupled with a portion of the second lower surface  722  but also coupled with said second side edge  732  of trace  70 ), in this manner, said solder mask  80  enables to be coupled with said trace  70  more securely, then it can prevent said solder mask  80  from peeling off said trace  70 , and then the reliability of said PCB  50  can be enhanced; and (2). Due to a portion of said solder mask  80  is placed within said recess  48  of insulator  40  and is coupled with said second lower surface  722  of trace  70 , then the width “W” of second lower surface  722  enables to become shorter, and then the materials of said conductive layer  90  coupled with the second lower surface  722  can be saved, in this manner, the cost for manufacturing said PCB  50  can be saved, and it is good to electronic industry. 
       FIG. 5  shows a PCB  55  comprising: an insulator  40  having an upper surface  41  and a lower surface  42 ; a trace  70  having an upper surface  71 , a lower surface  72  and a side edge  73 , wherein said side edge  73  consists of a first side edge  731  and a third side edge  733 , said first side edge  731  and said third side edge  733  are co-planar, said trace  70  embedded in said insulator  40 , in this manner, said trace  70  is encapsulated by said insulator  40 , wherein said first side edge  731  of side edge  73  and said lower surface  72  of trace  70  are encapsulated by said insulator  40 , and wherein said upper surface  71  of trace  70  is protruding said upper surface  41  of insulator  40  and said third side edge  733  of side edge  73  is protruding said upper surface  41  of insulator  40  too, in this manner, both said upper surface  71  of trace  70  and said third side edge  733  of side edge  73  exposed to atmosphere (i.e. both said upper surface  71  of trace  70  and said third side edge  733  of side edge  73  exposed out of said upper surface  41  of insulator  40 ) for connecting external substance(s), moreover, said trace  70  can be employed as either a ball pad or a path of transmitting electrical current; a solder mask  80  covering said upper surface  41  of insulator  40  and a portion of said upper surface  71  of trace  70  for protection, wherein another portion of said upper surface  71  of trace  70  exposed to the atmosphere for connecting external substance, wherein said solder mask  80  is optional; accordingly, By means of said upper surface  71  of trace  70  which is protruding the upper surface  41  of insulator  40 , it allows the thickness of said trace  70  to become thicker, in this manner, said PCB  55  enables to respond the demand of high current and high speed transmission, then it is more convenient for said PCB  55  to be used in electronic industries; In addition, said insulator  40  can further have a recess (refer to  FIG. 6 ; numeral “ 48 ”) on the lower surface  42  of insulator  40  as required, in case that said insulator  40  further having a recess ( 48 ), then a portion of said lower surface  72  of trace  70  can be placed therein and exposed to atmosphere (i.e. said a portion of lower surface  72  of trace  70  exposed out of said lower surface  42  of insulator  40 ) for connecting external substance(s); Moreover, said first side edge  731  and said third side edge  733  enable to be not co-planar (refer to  FIG. 7 ; numerals “ 731 ” and “ 733 ”) as required. 
       FIG. 6  shows a PCB  55  in accordance with the present invention, said structure of PCB  55  is similar to the structure of PCB  50  (shown in  FIG. 1 ), the differences between said PCB  55  and said PCB  50  are (1). said side edge  73  consists of a first side edge  731  and a third side edge  733 , said first side edge  731  and said third side edge  733  are co-planar, wherein said first side edge  731  of side edge  73  and said first lower surface  721  of trace  70  are encapsulated by said insulator  40 , wherein said upper surface  71  of trace  70  is protruding said upper surface  41  of insulator  40  and said third side edge  733  of side edge  73  is protruding said upper surface  41  of insulator  40  too, in this manner, both said upper surface  71  of trace  70  and said third side edge  733  of side edge  73  exposed to atmosphere, in this manner, it allows that said trace  70  further having an extending portion (refer to the detailed descriptions of  FIG. 7 ) which is extending on the upper surface  41  of insulator  40  and the thickness of said trace  70  enables to become thicker; and (2). Said trace  70  further having a dimple  724  which is on the second lower surface  722  and is exposed to the atmosphere, in this manner, the second lower surface  722  is uneven (i.e. not flat), meanwhile, By means of said dimple  724  of trace  70 , the area that said second lower surface  722  of trace  70  contacted to external substance(s) (such as solder ball, conductive wire, conductive layer, resistor, capacitor, and/or another trace) enables to be increased, in this manner, said trace  70  enables to be coupled with said external substance more securely, then it can prevent said external substance from peeling off said trace  70 , and then the reliability of said PCB  55  can be enhanced, wherein the depth (not shown) of said dimple  724  can be 1 μm, 2 μm or more than 2 μm. In additional, said trace  70  also can further have a second side edge (refer to  FIG. 2 ; numeral“ 732 ”) 
       FIG. 7  shows a PCB  50  in accordance with the present invention, said structure of PCB  50  is similar to the structure of PCB  55  (shown in  FIG. 6 ), the differences between said PCB  50  and said PCB  55  are (1). said trace  70  of PCB  50  further having an extending portion  74  which is a portion of said trace  70 , said extending portion  74  having an upper surface  741  and a lower surface  742 , said lower surface  742  of extending portion  74  coupled with said upper surface  41  of insulator  40 , in this manner, said extending portion  74  enables to be extended on said upper surface  41  of insulator  40  freely, as this result, it is more convenient for said PCB  50  to be used in the electronic industry; and wherein said side edge  73  consists of a first side edge  731  and a third side edge  733 , said first side edge  731  and said third side edge  733  are not co-planar, wherein said first side edge  731  of side edge  73  and said first lower surface  721  of trace  70  are encapsulated by said insulator  40 , and wherein said upper surface  71  of trace  70  is protruding said upper surface  41  of insulator  40  and said third side edge  733  of side edge  73  is protruding said upper surface  41  of insulator  40  too, in this manner, both said upper surface  71  of trace  70  and said third side edge  733  of side edge  73  exposed to atmosphere, meanwhile, said upper surface  71  of trace  70  comprised of a first upper surface  711  and a second upper surface  712 , and wherein both said first upper surface  711  and said second upper surface  712  are not co-planar, said first upper surface  711  is protruding the upper surface  41  of insulator, meanwhile, a portion of said first upper surface  711 , said second upper surface  712  of trace  70  and said upper surface  41  of insulator  40  are covered with the solder mask  80 , wherein said upper surface  741  of extending portion  74  is employed as a portion of said upper surface  71  of trace  70 , in this manner, said upper surface  71  of trace  70  further includes said upper surface  741  of extending portion  74 , and wherein said upper surface  741  of extending portion  74  (i.e. a portion of said upper surface  71  of trace  70 ) exposed to the atmosphere for connecting external substance; furthermore, the second upper surface  712  of trace  70  enables to be co-planar to the first upper surface  721  of trace  70  as required, accordingly, it is optional that the first upper surface  711  of trace  70  is not co-planar to the second upper surface  712  of trace  70 ; and (2). the second lower surface  722  is uneven such as conical and/or curvy or the like, in this manner, the area that said second lower surface  722  contacted to external substance(s) enables to be increased, then it can prevent said external substance from peeling off said trace  70 , and then the reliability of said PCB  50  is enhanced, in addition, said extending portion  74  and said trace  70  can be unitary or said extending portion  74  and said trace  70  can be made of different metals. 
       FIG. 8  shows a package  30  which is involved in a PCB  55  in accordance with the present invention, said structure of PCB  55  (shown in  FIG. 8 ) is similar to the structure of PCB  55  (shown in  FIG. 2 ), wherein the difference between said PCB  55  ( FIG. 8 ) and said PCB  55  ( FIG. 2 ) is: there is not any conductive layer ( 90 ) coupled with the second lower surface  722  of trace  70  (shown in  FIG. 8 ), compared with the second lower surface  722  of trace  70  (shown in  FIG. 2 ); said package  30  further comprised of: a chip  20  which is coupled with said solder mask  80  on the upper surface  41  of insulator  40 ; a conductive wire  95  which is electrically connected said chip  20  to said PCB  55 ; an encapsulant  60  which is made of SUMITOMO G1250 or the like, said encapsulant  60  seals said PCB  55 , said chip  20  and said conductive wire  95 ; and a solder ball  96 , wherein said solder ball  96  coupled with said second lower surface  722  and said second side edge  732 , accordingly, said PCB  55  enables to be coupled with said chip  20  and said encapsulant  60 , wherein said chip  20  can be employed as a flip chip, in case of flip chip, then said chip  20  coupled with said PCB  55  through a plurality of conductive bumps and sealed by an adhesive means such as encapsulant; moreover, in case that said package  30  coupled with a mother board (not shown) by said solder ball  96 , once said package  30  is attacked by an impact, due to the area that said second lower surface  722  (associated with said second side edge  732 ) of trace  70  contacted to said solder ball  96  is increased, then it allows said solder ball  96  enables to be coupled with said trace  70  more securely, then it can prevent said conductive layer  90  from peeling off said trace  70 , and then the reliability of said PCB  50  can be enhanced. Furthermore, due to the first lower surface  721  of trace  70  encapsulated by said insulator  40 , accordingly, said trace  70  can be held by said insulator  40  firmly too, in this manner, it can prevent said trace  70  from peeling off said insulator  40  while impacting, and then the reliability of said PCB  55  can be enhanced, consequently, By means of the second side edge  732  or the first lower surface  721  of trace  70  which is encapsulated by said insulator  40 , the reliability of said PCB  55  enables to be enhanced. 
     In accordance with the foregoing descriptions accompanying drawings, this invention has been described in terms of several preferred embodiments, various alternations and modifications can be made to become apparent to those skilled in the art; For examples: as shown in  FIG. 1 , wherein the second lower surface  722  enables to be not co-planar to the first lower surface  721  of trace  70  as required, then said trace  70  also having a second side edge ( 732 ), moreover, the upper surface  71  of trace enables to be protruding the upper surface  41  of insulator  40 , furthermore, an another trace  75  can be instead of said conductive layer  90  as required too; Accordingly, since many such various alterations and/or modifications can be made to the foregoing descriptions, it is to be understood that the scope of the invention is not limited to the disclosed embodiments but is defined by the appended claims.