Abstract:
A main board suitable for slim configurations is disclosed. The main board includes a multi-layer Printed Circuit Board (PCB) in which at least one recess is formed, a first integrated circuit placed in the recess, and a molding that covers the first integrated circuit and the bottom of the recess. The main board further comprising a cover over said recess, said cover being a second integrated circuit or a second PC board, which may further having attached an integrated circuit positioned within the recess.

Description:
CLAIM OF PRIORITY 
       [0001]    This application claims the benefit of the earlier filing data, under 35 U.S.C. § 119(a), to that patent application filed in the Korean Intellectual Property Office on Nov. 27, 2006 and assigned Serial No. 2006-117902, the entire disclosure of which is hereby incorporated by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to PC board fabrication, and in particular, to a PC board in which a plurality of electronic devices and integrated circuits are integrated on a multi-layer Printed Circuit Board (PCB). 
         [0004]    2. Description of the Related Art 
         [0005]    A multi-layer Printed Circuit Board (PCB) has a structure in which a plurality of insulation layers and a plurality of conductive pattern layers are deposited in turn, and is used as a main board having a plurality of electronic devices and integrated circuits integrated thereon for notebooks, portable wireless terminals, and the like that require high-density integration. 
         [0006]      FIG. 1  is a cross-sectional view of a conventional main board  100 . Referring to  FIG. 1 , the main board  100  includes a multi-layer PCB  110  in which a plurality of insulation layers and a plurality of conductive pattern layers are deposited in turn and integrated circuits  121 ,  122 , and  123  are placed on the PCB  110 . In addition to the integrated circuits  121 ,  122 , and  123 , a plurality of electronic devices may also be integrated on the main board  100 . 
         [0007]    The integrated circuits  121 ,  122 , and  123  may be in a form in which a semiconductor die, an interposer, or the like is repetitively deposited as a multi-layer structure. The integrated circuits  121 ,  122 , and  123  may be connected to some of the conductive pattern layers on the PCB  110  by a wire. A molding  130  may be formed on the PCB  110  on which the integrated circuits  121 ,  122 , and  123  are placed. 
         [0008]    However, since the molding  130  of the main board  100  is formed in a state where the integrated circuits  121 ,  122 , and  123  are disposed on the PCB  110 , the main board  100  thickness makes it difficult to apply main board  100  to slim portable wireless communication terminals or portable digital devices. 
       SUMMARY OF THE INVENTION 
       [0009]    An aspect of the present invention is to address at least the above problems and/or disadvantages. Accordingly, an aspect of the present invention is to provide a main board capable of providing multi-function and multi-integration capabilities with a slim thickness. 
         [0010]    According to one aspect of the present invention, there is provided a main board. The main board includes a multi-layer Printed Circuit Board (PCB) in which at least one recess is formed, a first integrated circuit placed in the recess, and a molding that covers the first integrated circuit and the bottom of the recess. 
         [0011]    According to another aspect of the present invention, there is provided a main board. The main board includes a multi-layer Printed Circuit Board (PCB) in which at least one recess is formed, a first integrated circuit and a second integrated circuit placed in the recess in a form in which they are deposited above and below with respect to each other, a molding that covers the first integrated circuit, the second integrated circuit, and the bottom of the recess, at least one electronic device integrated on the multi-layer PCB, and a third integrated circuit placed on the multi-layer PCB to cover the top of the recess. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The above and other features and advantages of exemplary embodiments of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: 
           [0013]      FIG. 1  is a cross-sectional view of a conventional main board; 
           [0014]      FIGS. 2A through 2G  are cross-sectional views showing steps of manufacturing a main board according to a first exemplary embodiment of the present invention; 
           [0015]      FIG. 3  is a cross-sectional view of a main board according to a second exemplary embodiment of the present invention; 
           [0016]      FIG. 4  is a cross-sectional view of a main board according to a third exemplary embodiment of the present invention; and 
           [0017]      FIG. 5  is a cross-sectional view of a main board according to a fourth exemplary embodiment of the present invention. 
       
    
    
       [0018]    Throughout the drawings, the same drawing reference numerals will be understood to refer to the same elements, features and structures. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0019]    The matters defined in the description such as a detailed construction and elements are provided to assist in a comprehensive understanding of exemplary embodiments of the invention. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiment described herein can be made without departing from the scope and spirit of the invention. Also, descriptions of well-known functions and constructions are omitted for clarity and conciseness. 
         [0020]      FIGS. 2A through 2F  are cross-sectional views showing steps of manufacturing a main board according to a first exemplary embodiment of the present invention.  FIG. 2G  is a cross-sectional view of the main board manufactured by the steps illustrated in  FIGS. 2A through 2F . 
         [0021]    Referring to  FIGS. 2A through 2G , the main board according to the first exemplary embodiment of the present invention includes a multi-layer Printed Circuit Board (PCB)  210  in which at least one recess  210   a  is formed, a first integrated circuit  220  placed in the recess  210   a  ( FIG. 2B ), a first interposer  230  ( FIG. 2C ), a second interposer  240  ( FIG. 2D ), a molding  250  ( FIG. 2E ) that covers the first integrated circuit  220 , the first interposer  230 , the second interposer  240 , and the bottom of the recess  210   a , electronic devices  320 , and a second integrated circuit  310  ( FIG. 2G ) placed on the multi-layer PCB  210  to cover the top of the recess  210   a.    
         [0022]    As illustrated in  FIG. 2A , the multi-layer PCB  210  includes deposited first through seventh insulation layers  211 ,  212 ,  213 ,  214 ,  215 ,  216 , and  217 , conductive circuit pattern layers  210   b  formed between the insulation layers  211 ,  212 ,  213 ,  214 ,  215 ,  216 , and  217 , and the recess  210   a  is formed by removing some of the insulation layers  211  through  217  using etching. The conductive circuit pattern layer may be formed by etching a conductive material such as copper (Cu) deposited between the insulation layers  211  through  217  or by forming via channels passing through the insulation layers  211  through  217  and then filling the channels with a conductive filler The conductive circuit pattern layer  210   b  formed in the bottom of the recess  210   a  may be provided as a land for electric connection with the first integrated circuit  220 . As illustrated in  FIG. 2B , the first integrated circuit  220  is connected with the conductive circuit pattern layer  210   b  formed in the bottom of the recess by a solder ball  221  inserted between the conductive circuit pattern layer  210   b  and the first integrated circuit  220 . As illustrated in  FIGS. 2C and 2D , a first interposer  230  and the second interposer  240  are sequentially placed on the first integrated circuit  220 . The first integrated circuit  220 , the first interposer  230 , and the second interposer  240  are electrically connected by a flip chip method using a flux dipping unit or by a reflow process. As illustrated in  FIG. 2E , molding  250  is formed in the recess  210   a  to bury the first integrated circuit  220 , the first interposer  230 , and the second interposer  240 . An epoxy molding compound for shielding electromagnetic waves may be used as the molding  250 . The molding  250  is formed in such a way that its height is smaller than the depth of the recess  210   a , thereby minimizing the thickness of the main board  200  when the main board  200  is combined with external other devices. 
         [0023]    In  FIG. 2F , a pad  261 , electrically connected to one of the conductive circuit pattern layers  210   b , which is exposed on the multi-layer PCB  210 , is formed for electric connection between the electronic device  320  and the second integrated circuit  310 . As illustrated in  FIG. 2G ; the electronic device  320  and the second integrated circuit  310  can be placed on the multi-layer PCB  210  by means of the pad  261 . 
         [0024]      FIG. 3  is a cross-sectional view of a main board  400  according to a second exemplary embodiment of the present invention. Referring to  FIG. 3 , the main board  400  includes a multi-layer PCB  410  in which at least one recess is formed, a first integrated circuit  420  and a second integrated circuit  430  placed in the recess in a form in which they are deposited above and below with respect to each other, a molding  440  that covers the first integrated circuit  420 , the second integrated circuit  430 , and the bottom of the recess, at least one electronic device  460  integrated on the multi-layer PCB  410 , and a third integrated circuit  450  placed on the multi-layer PCB  410  to cover the top of the recess. 
         [0025]    The multi-layer PCB  410  includes at least one insulation layers and conductive circuit pattern layers formed between or via the insulation layers. The first integrated circuit  420  and the second integrated circuit  430  are vertically deposited and may be in a form in which at least three integrated circuits are deposited. 
         [0026]      FIG. 4  is a cross-sectional view of a main board  500  according to a third exemplary embodiment of the present invention. Referring to  FIG. 4 , the main board  500  includes a first PCB  510  in which at least one recess is formed, at least one first integrated circuit  520  placed in the recess, a molding  530  that covers the first integrated circuit  520  and the bottom of the recess, at least one electronic device  550  integrated on the first PCB  510 , and a second PCB  540  placed on the first PCB  510  to cover the top of the recess. 
         [0027]    A second integrated circuit  543  is placed on a surface of the second PCB  540  that which faces the molding  530 , and the second PCB  540  may include a substrate  541  and a conductive circuit pattern layer  542  formed between the substrate  541  and the second integrated circuit  543 . 
         [0028]      FIG. 5  is a cross-sectional view of a main board  600  according to a fourth exemplary embodiment of the present invention. Referring to  FIG. 5 , the main board  600  includes a first PCB  610  in which at least one recess is formed, at least one integrated circuit  620  placed in the recess, a first interposer  630  and a second interposer  640  placed on the integrated circuit  620 , a first molding  650  formed in the recess to bury the integrated circuit  620 , the first interposer  630 , and the second interposer  640 , at least one electronic device  670  integrated on the first PCB  610 , and a second PCB  660  placed on the first PCB  610  to cover the top of the recess and having a second molding  662  facing the first molding  610 . 
         [0029]    The second PCB  660  includes a substrate  661  and may have at least one electronic device or Radio Frequency (RF) device placed on a surface of the substrate  661 , which faces the first molding  650 . The second molding  662  may be formed to surround the at least one electronic device or RE device. 
         [0030]    In the main board having a plurality of electronic parts and integrated circuits integrated thereon according to the present invention, the integrated circuits are mounted in the recess of the PCB. Therefore, the main board can be easily applied to slim portable wireless communication terminals or portable electronic devices. In other words, the present invention can offer the main board capable of providing multi-function and multi-integration capabilities with a slim thickness, thereby reducing the unit cost of the main board. 
         [0031]    While the invention has been shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.