Abstract:
An electronic module is provided, including an electronic element and a strengthening layer formed on a side surface of the electronic element but not formed on an active surface of the electronic element so as to strengthen the structure of the electronic module. Therefore, the electronic element is prevented from being damaged when the electronic module is picked and placed.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to electronic modules, and more particularly, to an electronic module and a fabrication method thereof so as to improve the product yield. 
         [0003]    2. Description of Related Art 
         [0004]    Along with the progress of electronic industries, electronic products are developed toward the trend of miniaturization and multi-function. Accordingly, various package types have been developed. To meet the demands of semiconductor devices for high integration, miniaturization and high electrical performance, flip-chip bonding technologies have been developed. 
         [0005]    To achieve flip-chip bonding, a plurality of conductive bumps are formed on an active surface of a chip for electrically connecting the active surface of the chip to an external electronic device or a packaging substrate. As such, the size of the overall package structure is greatly reduced. Further, the structure dispenses with bonding wires as required in the prior art. As such, the electrical impedance of the structure is reduced, thereby improving the electrical performance and avoiding signal distortion during transmission. Therefore, flip-chip bonding technologies are becoming increasing popular. 
         [0006]      FIG. 1  is a schematic exploded cross-sectional view of a conventional flip-chip package  1 . 
         [0007]    Referring to  FIG. 1 , the flip-chip package  1  has a chip  11  and a packaging substrate  9 . The chip  11  has opposite active and inactive surfaces  11   a ,  11   b . A plurality of electrode pads  12  are formed on the active surface  11   a  of the chip  11  and a plurality of solder balls  13  are correspondingly formed on the electrode pads  12 . The substrate  9  has a plurality of conductive pads  90 . The chip  11  is disposed on the packaging substrate  9  with the solder balls  13  correspondingly bonded to the conductive pads  90 , thereby forming the flip-chip package  1 . 
         [0008]    However, the chip  11  has a low structural strength due to its exposed inactive surface  11   b  and side surface  11   c . Therefore, when the flip-chip package  1  is picked up and placed at a suitable position and subjected to an SMT (Surface Mount Technology) process, cracking easily occurs to the chip  11 , thus reducing the product reliability. 
         [0009]    Therefore, how to overcome the above-described drawbacks has become critical. 
       SUMMARY OF THE INVENTION 
       [0010]    In view of the above-described drawbacks, the present invention provides an electronic module, which comprises: an electronic element having an active surface with a plurality of electrode pads, an inactive surface opposite to the active surface, and a side surface connecting the active and inactive surfaces; and a strengthening layer formed on the side surface of the electronic element but not formed on the active surface of the electronic element. 
         [0011]    The above-described electronic module can further comprise a separation portion formed on the strengthening layer on the side surface of the electronic element in a manner that the strengthening layer is sandwiched between the side surface of the electronic element and the separation portion. 
         [0012]    In the above-described electronic module, the separation portion can have a width less than 1 mm. 
         [0013]    The present invention further provides a method for fabricating an electronic module, which comprises the steps of: providing a substrate having a plurality of electronic elements and a plurality of separation portions each formed between adjacent two of the electronic elements, wherein each of the electronic elements has an active surface with a plurality of electrode pads and an inactive surface opposite to the active surface; forming at least an opening in each of the separation portions, causing each of the electronic elements to have a side surface connecting the active and inactive surfaces thereof; forming a strengthening layer in the openings of the separation portions and on the side surfaces of the electronic elements; and singulating the electronic elements along the separation portions. 
         [0014]    In the above-described method, the separation portions can have a width in a range of 10 um to 4 mm. 
         [0015]    In the above-described method, the singulation path along the separation portions can be less in width than the separation portions 
         [0016]    In the above-described method, if a plurality of openings are formed in each of the separation portions, the singulation path along the separation portion can be positioned between the openings of the separation portion. 
         [0017]    In the above-described electronic module and method, the strengthening layer can be formed around the side surface of the electronic element. 
         [0018]    In the above-described electronic module and method, the strengthening layer can be made of an insulating material. 
         [0019]    In the above-described electronic module and method, the strengthening layer can further be formed on the inactive surface of the electronic element. 
         [0020]    In the above-described electronic module and method, an RDL (Redistribution Layer) structure can further be formed on the strengthening layer, the separation portion and the active surface of the singulated electronic element and electrically connected to the electrode pads of the electronic element. 
         [0021]    In the above-described electronic module and method, an RDL structure can further be formed on the strengthening layer and the active surface of the singulated electronic element and electrically connected to the electrode pads of the electronic element. 
         [0022]    In the above-described electronic module and method, a plurality of conductive elements can be formed on the active surface of the electronic element and electrically connected to the electrode pads of the electronic element. 
         [0023]    In the above-described electronic module and method, the singulated electronic element can be bonded to a packaging substrate via the active surface thereof. 
         [0024]    Therefore, by forming the strengthening layer to encapsulate the inactive and side surfaces of the electronic element, the present invention strengthens the structure of the electronic module so as to prevent damage of the electronic element when the electronic module is subjected to an SMT (Surface Mount Technology) process or transported, thus improving the product yield. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0025]      FIG. 1  is a schematic exploded cross-sectional view of a conventional flip-chip package; 
           [0026]      FIGS. 2A to 2G  are schematic cross-sectional views showing a method for fabricating an electronic module according to the present invention, wherein FIGS.  2 C′ and  2 G′ show another embodiment of  FIGS. 2C and 2G ; and 
           [0027]      FIGS. 3A and 3B  are schematic cross-sectional views showing different embodiments of the electronic module of the present invention, wherein FIGS.  3 A′ and  3 B′ are schematic upper views of  FIGS. 3A and 3B , respectively. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0028]    The following illustrative embodiments are provided to illustrate the disclosure of the present invention, these and other advantages and effects can be apparent to those in the art after reading this specification. 
         [0029]    It should be noted that all the drawings are not intended to limit the present invention. Various modifications and variations can be made without departing from the spirit of the present invention. Further, terms such as “first”, “second”, “on”, “a” etc. are merely for illustrative purposes and should not be construed to limit the scope of the present invention. 
         [0030]      FIGS. 2A to 2G  are schematic cross-sectional views showing a method for fabricating an electronic module  2  according to the present invention. 
         [0031]    Referring to  FIG. 2A , a full-panel substrate  20  is provided, which has a plurality of electronic elements  20 ′ and a plurality of separation portions  21  formed between the electronic elements  20 ′. 
         [0032]    In the present embodiment, each of the electronic elements  20 ′ has an active surface  20   a  with a plurality of electrode pads  200  and an inactive surface  20   b  opposite to the active surface  20   a . Further, a passivation layer  201  is formed on the active surfaces  20   a  of the electronic elements  20 ′, and the electrode pads  200  of the electronic elements  20 ′ are exposed from the passivation layer  201 . 
         [0033]    Each of the electronic elements  20 ′ can be an active element such as a semiconductor chip, a passive element such as a resistor, a capacitor or an inductor, or a combination thereof. In the present embodiment, the substrate  20  is a silicon wafer, and the electronic elements  20 ′ are active elements. 
         [0034]    Referring to  FIG. 2B , a carrier  23  is disposed on the passivation layer  201 . In the present embodiment, a release layer  231  is formed between the carrier  23  and the passivation layer  201  so as to facilitate subsequent removal of the carrier  23  from the passivation layer  201 . 
         [0035]    Referring to  FIG. 2C , an opening  24  is formed in each of the separation portions  21  by cutting. As such, each of the electronic elements  20 ′ has a side surface  20   c  connecting the active and inactive surfaces  20   a ,  20   b  of the electronic element  20 ′. 
         [0036]    In the present embodiment, each of the separation portions  21  is completely removed to form the opening  24 . The width L of the opening  24 , i.e., the width of the separation portion  21 , is in a range of 10 um to 3 mm. Further, the inactive surfaces  20   b  of the electronic elements  20 ′ can be optionally thinned by grinding. 
         [0037]    In another embodiment, referring to FIG.  2 C′, during the cutting process, a plurality of openings  24 ′ are formed in each of the separation portions  21 . That is, each of the separation portions  21  is partially removed, leaving a remaining portion  21 ′. The width L′ of the separation portion  21  is in a range of 15 um to 4 mm. 
         [0038]    Referring to  FIG. 2D , a strengthening layer  25  is formed in the openings  24  and on the electronic elements  20 ′ so as to cover the side surfaces  20   c  and the inactive surfaces  20   b  of the electronic elements  20 ′. 
         [0039]    In the present embodiment, the strengthening layer  25  is completely filled in the openings  24  and formed around the side surfaces  20   c  of the electronic elements  20 ′. The strengthening layer  25  is made of an insulating material, for example, a molding compound material, a dry film material, a photoresist material or a solder mask material. 
         [0040]    Referring to  FIG. 2E , the carrier  23  and the release layer  231  are removed to expose the electrode pads  200  of the electronic elements  20 ′, the passivation layer  201  and the strengthening layer  25 . 
         [0041]    Referring to  FIG. 2F , an RDL (Redistribution Layer) process is performed to form an RDL structure  27  on the passivation layer  201 . The RDL structure  27  is electrically connected to the electrode pads  200  of the electronic elements  20 ′. Then, a plurality of conductive elements  28  are formed on the RDL structure  27 . 
         [0042]    In the present embodiment, the RDL structure  27  has a circuit layer  271  formed on the passivation layer  201  and electrically connected to the electrode pads  200  of the electronic elements  20 ′, and an insulating layer  273  formed on the circuit layer  271 . Further, portions of the circuit layer  271  are exposed from the insulating layer  273  for mounting the conductive elements  28 . 
         [0043]    The conductive elements  28  are solder balls, metal bumps or a combination thereof. 
         [0044]    Referring to  FIG. 20 , a singulation process is performed. That is, the full-panel substrate  20  is cut along a cutting path  26  (i.e., along the separation portions  21 ) so as to separate the electronic elements  20 ′ from one another, thus forming a plurality of electronic modules  2 . 
         [0045]    In the present embodiment, the width S of the cutting path  26  is less than the width L of the openings  24 . 
         [0046]    In another embodiment, continued from FIG.  2 C′, the cutting path  26  is positioned between the openings  24 ′, as shown in FIG.  2 G′. As such, a plurality of electronic modules  2 ′ are obtained. Each of the electronic modules  2 ′ has a separation portion  21 ′ embedded in the strengthening layer  25  on the side surface of the electronic element  20 ′. That is, the openings  24 ′ are positioned between the separation portion  21 ′ and the electronic element  20 ′, and the surface of the separation portion  21 ′ is flush with the side surface of the strengthening layer  25 . The RDL structure  27  is formed on the strengthening layer  25 , the separation portion  21 ′ and the active surface  20   a  of the electronic element  20 ′ and electrically connected to the electrode pads  200  of the electronic element  20 ′. 
         [0047]    Further, the strengthening layer  25  can be partially removed so as to expose the inactive surface  20   b  of the electronic element  20 ′. For example, the inactive surface  20   b  of the electronic element  20 ′ is flush with the upper surface of the strengthening layer  25 , as shown in  FIG. 3B . 
         [0048]    Therefore, by forming the strengthening layer  25  to encapsulate the electronic element  20 ′, the present invention strengthens the structure of the electronic module  2 ,  2 ′ so as to prevent damage of the electronic element  20 ′ when the electronic module  2 ,  2 ′ is subjected to an SMT (Surface Mount Technology) process or transported, thus improving the product yield. 
         [0049]    Referring to  FIGS. 3A and 3B , the present invention further provides an electronic module  2 ,  2 ′, which has: an electronic element  20 ′ having an active surface  20   a  with a plurality of electrode pads  200 , an inactive surface  20   b  opposite to the active surface  20   a , and a side surface  20   c  connecting the active and inactive surfaces  20   a ,  20   b ; and a strengthening layer  25  formed on the side surface  20   c  of the electronic element  20 ′ but not formed on the active surface  20   a  of the electronic element  20 ′. 
         [0050]    The strengthening layer  25  can be made of an insulating material. 
         [0051]    The electronic module  2 ,  2 ′ can further have an RDL structure  27  formed on the strengthening layer  25  and the active surface  20   a  of the electronic element  20 ′ and electrically connected to the electrode pads  200  of the electronic element  20 ′. 
         [0052]    The electronic module  2 ,  2 ′ can further have a plurality of conductive elements  28  formed on the active surface  20   a  of the electronic element  20 ′ (or the RDL structure  27 ) and electrically connected to the electrode pads  200  of the electronic element  20 ′. 
         [0053]    In an embodiment, referring to FIGS.  3 A′ and  3 B′, the strengthening layer  25  are formed around the side surface  20   c  of the electronic element  20 ′. 
         [0054]    In an embodiment, the strengthening layer  25  is further formed on the inactive surface  20   b  of the electronic element  20 ′, as shown in  FIG. 3A . Alternatively, the inactive surface  20   b  of the electronic element  20 ′ is exposed from the strengthening layer  25 , as shown in  FIG. 3B . 
         [0055]    In an embodiment, the electronic module  2 ′ further has a separation portion  21 ′ formed on the strengthening layer  25  on the side surface  20   c  of the electronic element  20 ′ in a manner that the strengthening layer  25  is sandwiched between the side surface  20   c  of the electronic element  20 ′ and the separation portion  21 ′. Further, the RDL structure  27  is formed on the separation portion  21 ′. The width t of the separation portion  21 ′ is less than 1 mm. 
         [0056]    In an embodiment, the electronic element  20 ′ is flip-chip disposed on a packaging substrate  8  via the active surface  20   a  thereof, with the conductive elements  28  bonded to the conductive pads  80  of the packaging substrate  8 . 
         [0057]    Therefore, the present invention strengthens the structure of the electronic module through the strengthening layer so as to prevent damage of the electronic element and improve the product yield. 
         [0058]    The above-described descriptions of the detailed embodiments are only to illustrate the preferred implementation according to the present invention, and it is not to limit the scope of the present invention. Accordingly, all modifications and variations completed by those with ordinary skill in the art should fall within the scope of present invention defined by the appended claims.