Abstract:
A package structure for connection with an output/input module is disclosed. The package structure can be applied to conventional multi-chip packages and system in packages. The package structure defines at least one insertion cavity that is vertically or horizontally disposed. By simply inserting an output/input module into the insertion cavity, an electrical connection can be established between the output/input module and the package structure. Accordingly, the package structure thus constructed can address the repairing, replacement and upgrading problems of electronic components encountered by a package structure that adopts the conventional soldering connection method.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a package structure for connection with an output/input module, and particularly to a package structure that allows easy replacement of an output/input module connected therewith. 
     2. Description of Prior Art 
     In the current electronic industry, electronic components such as multi-chip packages and system in packages (SIPs) are generally fixed on a substrate and electrically connected to metal traces on the substrate by a lead frame and a plurality of solder bumps. Under the demands for light, thin, short, small and high performance electronic products, the electronic components in these electronic products and the contact pins thereof are both increased in number and reduced in size. 
     The solder bumps play an important role since they are responsible for the transmission of electrical signals. Once the solder bumps are damaged, the electronic components may be damaged and thus the entire electronic component may fail in function. Damage of the solder bumps is generally due to thermal fatigue when they are subjected to high temperature variations. It is well known that a package structure consists of several parts among which the solder bumps are the ones that are located at the connection interfaces of the package structure. When subjected to high temperature variations, the solder bumps induce a significant amount of thermal stress therein. This thermal stress causes the solder bumps to crack and peel, leading to failure of the package structure. The lower the height of the solder bumps, the greater the thermal fatigue damage to the solder bumps. Accordingly, for a light, thin, short, small and high performance package structure, the life span of such a package structure is directly impacted by the solder bumps. 
     In case that such problems occur, it is necessary to repair or replace the electronic components that are damaged due to the damage of the solder bumps, so that the normal operation of the electronic product containing these components can be maintained. Since these electronic components are generally reflow soldered by conventional reheating techniques to securely and electrically affix the components to a circuit board, rework of the solder joints must be performed when repairing or replacement of the electronic components is required. However, in some situations, such as for a flip-chip package or a three-dimensional package, reworkability is generally not available. For a flip-chip package, the underfills thereof that are mainly epoxy-based materials are not reworkable after curing. Three-dimensional (3D) packages, which are one kind of SiP (System in Package) packages, are characterized in reduced package volume and initial system integration. However, most of current 3D package architectures are not reworkable. 
     In the development stage of electronic products, various experiments and testing procedures must be conducted. Currently, electronic components of the electronic products are first mounted on a substrate by the conventional soldering technology, and then testing is carried out to check whether the function of the electronic product is satisfactory. If the tested electronic product is unsatisfactory in performance or fails in function, electronic components of the tested product that are found to be not properly functioning must be replaced. However, after the replacement and rework of these electronic components, the reliability of the electronic product may be impaired and even the function of the electronic product may be adversely affected. 
     Hence, an improved package structure is desired to address the repair, replacement and updating problems of electronic components thereof that are encountered in the prior art. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a package structure that allows easy replacement of an output/input module connected therewith. 
     To achieve the above object, the present invention provides a package structure for connection with an output/input module, comprising at least one substrate, at least one insertion cavity and a plurality of contacts. The substrate has metal traces formed thereon for transmitting electrical signals. Each insertion cavity is substantially a portion of the substrate, and has an opening defined in one surface of the substrate for allowing insertion of the output/input module. The contacts are formed on inner walls of the insertion cavity for electrical connection with corresponding contacts on the output/input module. 
     Each of the contacts has a roughened surface formed by roughing treatment for enhancing reliability of electrical connection between the contact and a corresponding contact of the output/input module. An anti-wear layer is further formed on the roughened surface. 
     The package structure of the present invention further comprises at least one dielectric layer arranged between confronting surfaces of opposing substrates. 
     The package structure constructed according to the present invention effectively avoids discarding of the entire package structure in case of damage of electronic components thereof, and also avoids replacement of the entire package structure when upgrading of some electronic components thereof is required. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention may be best understood through the following description with reference to the accompanying drawings, in which: 
         FIGS. 1A to 1C  are schematic views showing three different configurations of an insertion cavity of the package structure of the present invention for electrically receiving an output/input module therein. 
         FIGS. 2A to 2H  sequentially show the production steps of a package structure according to the first embodiment of the present invention, which allows an output/input module to be inserted therein in a vertical direction. 
         FIG. 3  is a horizontal cross-sectional view showing the configuration of an insertion cavity of the package structure according to the first embodiment of the present invention. 
         FIGS. 4A to 4H  sequentially show the production steps of a package structure according to the second embodiment of the present invention, which allows an output/input module to be inserted therein in a horizontal direction. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to the drawings and in particular to  FIGS. 1A to 1C , which schematically and respectively show package structures in accordance with different embodiments of the present invention, all designated with the same reference numeral  101  for simplicity, and each forming one or more insertion cavities broadly designated at  103  functioning to electrically and releasably receive an output/input module  107  therein. As shown in the drawings, each of the package structures  101  in accordance with the present invention defines at least one insertion cavity  103  for receiving and establishing electrical connection with an output/input module  107 . The insertion cavity  103  has an opening defined in one surface of the package structure  101  for allowing insertion of the output/input module  107 . 
     In the embodiment of  FIG. 1A , the package structure  101  has two insertion cavities  103  vertically defined in an upper surface thereof. An output/input module  107  can be selectively inserted into either one or both of the insertion cavities  103  in a vertical direction as indicated by the arrow shown in  FIG. 1A .  FIG. 1B  illustrates another embodiment, in which the package structure  101  has only one insertion cavity  103  horizontally defined in one side surface thereof. An output/input module  107  can be selectively inserted into the insertion cavity  103  in a horizontal direction.  FIG. 1C  illustrates a further embodiment of the present invention, in which the package structure  101  forms an insertion port  104  on an upper surface thereof with the opening of the insertion port  104  facing sideways so that an output/input module  107  can be selectively inserted into the insertion port  104  in a horizontal direction as indicated by the arrow shown in  FIG. 1C . The insertion port  104  in  FIG. 1C  is different from those in  FIGS. 1A and 1B  in that it is in the form of a bus slot. 
     Each insertion cavity  103  and insertion port  104  shown in  FIGS. 1A to 1C  has a plurality of inelastic but electrically conductive contacts formed on inner walls thereof. Each contact is made of an electrically conductive metal material for electrical connection with corresponding contacts on the output/input module  107 . Detailed description of the contacts will be provided below. 
       FIGS. 2A to 2H  sequentially show the production steps of the package structure corresponding to an embodiment of the present invention shown in  FIG. 1A , which allows an output/input module to be inserted therein in a vertical direction. A substrate  201  is first provided as shown in  FIGS. 2A and 2B , which are respectively a top view and a cross-sectional side elevational view of the substrate  201 . The substrate  201  has a plurality of metal or conductive traces  202  formed thereon for transmitting electrical signals. In the embodiment illustrated, the metal traces  202  are formed on opposite upper and lower surfaces of the substrate  201  by conventional methods including plating, exposure, etching and laser drilling, but not including application of a solder mask to the substrate  201 . Preferably, the conductive traces  202  are made of a hard gold material that is resistant to abrasion and high in conductivity. 
       FIGS. 2C and 2D  illustrate the second step of the production process of the package structure and  FIG. 2C  is a top view of the substrate  201  and  FIG. 2D  is a cross-sectional side view of  FIG. 2C . An insertion cavity  203  is defined in the upper surface of the substrate  201  at a desired location by etching, and a conductive material, for example metal, such as hard gold, is plated on inner walls of the insertion cavity  203  to form an electrical conductive layer  208 . The insertion cavity  203  has an opening defined in the upper surface of the substrate  201  for allowing vertical insertion of an output/input module. As clearly shown in  FIG. 2C , the insertion cavity  203  is elongated in a direction perpendicular to the extending direction of the metal traces  202  on the substrate  201 . 
       FIGS. 2E and 2F  illustrate the third step of the production process of the package structure and  FIG. 2E  is a top view of the substrate  201  and  FIG. 2F  is a cross-sectional side view of  FIG. 2E . As shown in  FIG. 2E , undesired portions of the electrical conductive layer  208  are removed by laser etching or other known means to thereby form a plurality of electrical conductive contacts  204  on the inner walls of the insertion cavity  203 . It is understandable that since these contacts  204  are formed by first subjecting the inner walls of the insertion cavity  23  to plating of conductive material to form the electrical conductive layer  208 , followed by removing the undesired portions from the electrical conductive layer  208  by means of laser etching or other known means, these contacts  204  are generally inelastic. Each contact  204  is then subjected to roughing treatment to form a roughened surface so as to enhance the reliability of electrical connection between the contact  204  and a corresponding contact  2070  of the output/input module  207  ( FIG. 2H ). As shown in  FIG. 2F , an anti-wear layer  205  is further plated on each contact  204  after the roughening treatment. 
       FIGS. 2G and 2H  illustrate the final step of the production process of the package structure and  FIG. 2G  is a top view of the substrate  201  and  FIG. 2H  is a cross-sectional side view of  FIG. 2G . As shown in  FIGS. 2G and 2H , a solder mask layer  209  is provided on the substrate  201 . A plurality of guiding and retaining structures  206  is further disposed around the periphery of the insertion cavity  203  for guiding the insertion of the output/input module  207  and retaining the inserted output/input module  207  in position, so that damage to the output/input module  207  caused by external impact forces can be prevented. 
       FIG. 3  is a horizontal cross-sectional view showing the configuration of an insertion cavity  203  of the package structure according to the present invention. As described above, the insertion cavity  203  is first plated with a conductive metal material on the inner walls thereof to form the electrical conductive layer  208 , and the undesired portions of the electrical conductive layer  208  are then removed by laser etching to thereby form the plurality of electrical conductive contacts  204  on the inner walls of the insertion cavity  203 . Therefore, the thus formed insertion cavity  203  is capable to form electrical connection with various insertable electronic devices, rather than just a specific output/input module  207  exemplified herein, and has high compatibility with various output/input modules  207 . 
       FIGS. 4A to 4H  sequentially show the production steps of a package structure according to another embodiment of the present invention, which allows an output/input module to be inserted therein in a horizontal direction. A first substrate  401  is provided first, as shown in  FIGS. 4A and 4B , which are respectively a top view and a cross-sectional side elevational view of the first substrate  401 . The first substrate  401  has a plurality of metal or conductive traces  402  formed thereon for transmitting electrical signals. These metal traces  402  are formed on opposite upper and lower surfaces of the first substrate  401  by conventional methods including plating, exposure, etching and laser drilling, but not including application of a solder mask to the substrate  401 . As shown in  FIG. 4B , the metal traces  402  formed on opposite upper and lower surfaces of the first substrate  401  are electrically connected with each other using PTH (Plated Through Hole) technology. Preferably, the metal traces  402  are made of hard gold for the superior characteristics of the hard gold in resisting abrasion and having excellent conductivity. 
     As shown in  FIG. 4A , a first cutout corresponding to a desired final insertion cavity  403  as circled in the drawing is defined in a side edge of the first substrate  401  at a desired location by etching or other known and suitable means. The first cutout corresponding to the insertion cavity  403  has an opening defined in the side edge of the first substrate  401  for allowing horizontal insertion of an output/input module. As clearly shown in  FIG. 4A , the first cutout is elongated in a direction parallel to the extending direction of the metal traces  402  on the first substrate  401 . 
       FIG. 4C  illustrates the second step of the production process of the package structure. At this step, a second substrate or an upper board  406  is further provided. Similar to the first substrate  401 , the upper board  406  has a plurality of metal traces  402  formed on opposite upper and lower surfaces thereof for transmitting electrical signals. What is different is that these metal traces  402  are formed on the upper board  406  by conventional methods including plating, exposure, etching and laser drilling, and also including a step of applying a solder mask. The metal traces  402  formed on the upper and lower surfaces of the upper board  406  are also electrically connected with each other using PTH technology. A conductive metal material, such as copper, silver or gold, is then plated on the lower surface of the upper board  406  at a location corresponding to the cutout defined in the side edge of the first substrate  401  so as to form an electrical conductive layer. Undesired portions of this electrical conductive layer are removed by laser etching to thereby form a plurality of electrical conductive contacts  404 . It is understandable that since these contacts  404  are formed by first plating the lower surface of the upper board  406  at a location corresponding to the cutout defined in the side edge of the first substrate  401  to form an electrical conductive layer and then removing the undesired portions of the electrical conductive layer by means of laser etching, these contacts  404  are generally inelastic. Each contact  404  is then subjected to roughing treatment to form a roughened surface so as to enhance the reliability of electrical connection between the contact  404  and a corresponding contact  4070  of the output/input module  407  ( FIG. 4H ). An anti-wear layer  405  is further plated on each contact  404  after the roughening treatment. 
       FIG. 4D  illustrates the third step of the production process of a package structure according to the second embodiment of the present invention. At this third step, a third substrate or a lower board  408  is further provided. Similar to the first substrate  401 , the lower board  408  also has a plurality of metal traces  402  formed on opposite upper and lower surfaces thereof for transmitting electrical signals. What is different is that these metal traces  402  are formed on the lower board  408  by conventional methods including plating, exposure, etching and laser drilling, and also including the step of applying a solder mask. The metal traces  402  formed on opposite upper and lower surfaces of the lower board  408  are also electrically connected with each other using PTH technology. A conductive material, for example metal, such as copper, silver or gold, is then plated on the upper surface of the lower board  408  at a location corresponding to the cutout defined in the side edge of the first substrate  401  so as to form an electrical conductive layer. Undesired portions of this electrical conductive layer are removed by laser etching to thereby form a plurality of electrical conductive contacts  404 . It is understandable that, since these contacts  404  are formed by first plating the upper surface of the lower board  408  at a location corresponding to the first cutout defined in the side edge of the first substrate  401  to form an electrical conductive layer and then removing undesired portions of the electrical conductive layer by means of laser etching, they are generally inelastic. Each contact  404  is then subjected to a roughing treatment to form a roughened surface thereon, so as to enhance the reliability of electrical connection between the contact  404  and a corresponding contact  4070  on the output/input module  407  ( FIG. 4H ). An anti-wear layer  405  is further plated on each contact  404  after the roughening treatment. 
     Although it is described in the above embodiment that the first substrate  401 , the upper board  406  and the lower board  408  are manufactured in successive order, it is noted that the present invention is not so limited. The first substrate  401 , the upper board  406  and the lower board  408  can also be manufactured in other orders. 
       FIGS. 4E and 4F  illustrate the fourth step of the production process of the package structure and  FIG. 4E  is a top view illustrating the constituent components of the package structure of the embodiment and  FIG. 4F  is a cross-sectional side view of  FIG. 4E . As shown in  FIG. 4E , upper and lower dielectric layers  409  are further provided, and are respectively sandwiched between the upper board  406 , the first substrate  401  and the lower board  408 . Each dielectric layer  409  is preferably made of ceramic or silicon dioxide to reduce the leakage current and avoid decrease of the driving voltage. A cutout is defined in one side edge of each dielectric layer  409  by etching, and is aligned with the first cutout of the first substrate  401 . The upper board  406 , the upper dielectric layer  409 , the first substrate  401 , the lower dielectric layer  409  and the lower board  408  are then laminated with each other to form a package structure as shown in  FIG. 4G . 
     Referring to  FIG. 4G , the package structure constructed in accordance with the embodiment is shown. As described above, this package structure is obtained by laminating the upper board  406 , the upper dielectric layer  409 , the first substrate  401 , the lower dielectric layer  409  and the lower board  408 . A desired final insertion cavity  403  for receiving the output/input module  407  is also formed by lamination of these components, which is corresponding to those cutouts defined in the side edges of the first substrate  401  and the two dielectric layers  409 . As shown, the insertion cavity  403  thus formed has a plurality of inelastic but electrically conductive contacts  404  on the top and the bottom thereof. Each contact  404  has a roughened surface formed by roughing treatment for enhancing the reliability of electrical connection between the contact  404  and a corresponding contact  4070  of the output/input module  407 . An anti-wear layer  405  is further formed on the roughened surface of each contact  404 . 
     Referring to  FIG. 4H , after lamination, the upper board  406 , the first substrate  401  and the lower board  408  are electrically connected with each other by interconnection of the metal traces  402  thereof using the PTH technology. In order to reliably retain the constituent components of the package structure in position, a reinforcing member  410  is further disposed around a periphery of the package structure. This reinforcing member  410  can be in the form of a reinforcing strip, a reinforcing clip or a metal ring or other suitable devices. 
     As described above, by defining an insertion cavity to receive an output/input module and thus establishing an electrical connection therebetween, the package structure constructed according to the present invention effectively avoids discarding of the entire package structure in case of damage of the output/input module, and also avoids replacement of the entire package structure when attempting to upgrade one of a number of output/input modules connected to the package is required. Therefore, the package structure constructed in accordance with the present invention addresses the problems associated with repairing, replacement and upgrading of electronic components encountered by a package structure that adopts the conventional soldering connection method. 
     It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.