Abstract:
Embodiments provide a semiconductor device package and a method for fabricating thereof. The package includes a silicon substrate having a semiconductor device and a metal layer thereon; an insulator ring formed in the silicon substrate and surrounding a portion of a silicon material below the metal layer; and a conductive layer disposed below a backside of the silicon substrate and extended to contact the portion of the silicon material surrounded by the insulator ring below the metal layer.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a divisional Application of pending U.S. patent application Ser. No. 11/987,228, filed Nov. 28, 2007, which claims priority of Taiwan Patent Application No. 096129207, filed on Aug. 8, 2007, the entirety of which are incorporated by reference herein. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention relates to semiconductor device packages, and more particularly to a semiconductor device package with insulator ring. 
         [0004]    2. Description of the Related Art 
         [0005]    Photosensitive integrated circuits play an important role in image sensor devices which are widely used in consumer devices, such as digital cameras, digital video recorders, mobile phones, and portable devices. With consumer&#39;s demanding lighter and lighter portable devices, requirement to reduce the dimensions of image sensor packages has increased. 
         [0006]      FIG. 1  is a cross section of a conventional image sensor package  1 . In  FIG. 1 , a substrate  2  with an image sensor device  4  electrically connected to an extending bonding pad  6  thereon is provided. A covering plate  8  is then disposed on the substrate  2  followed by the substrate  2  being attached to a carrying plate  14 . As shown in  FIG. 1 , a conductive layer  10  is formed on a backside of the carrying plate  14  and extended to the sidewalls of the carrying plate  14  and the substrate  2  electrically connects the extending bonding pad  6  to a solder ball  12 . The image sensor package has large dimensions since the image sensor package structures require both the substrate and the carrying plate which have a certain thickness. Moreover, because the conductive layer is formed close to an exterior area of the image sensor package, for example the sidewalls of the substrate and the carrying plate, damage to the conductive layer may occur during fabrication, resulting in device failure. 
         [0007]    Thus, an image sensor package and fabrication method thereof eliminating the described problems is needed. 
       BRIEF SUMMARY OF INVENTION 
       [0008]    Accordingly, the invention provides a semiconductor device package. An exemplary embodiment of the semiconductor device package comprises a silicon substrate having a semiconductor device and a metal layer thereon; an insulator ring formed in the silicon substrate and surrounding a portion of a silicon material below the metal layer; and a conductive layer disposed below a backside of the silicon substrate and extended to contact the portion of the silicon material surrounded by the insulator ring below the metal layer. 
         [0009]    A detailed description is given in the following embodiments with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0010]    The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein: 
           [0011]      FIG. 1  is a cross section of a conventional image sensor package; 
           [0012]      FIGS. 2-7  are schematic views illustrating a method for fabricating an image sensor package according to an embodiment of the invention; and 
           [0013]      FIG. 8  is a flow chart of a method for fabricating an image sensor package according to the embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF INVENTION 
       [0014]    The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims. 
         [0015]      FIGS. 2-7  are schematic views illustrating a method for fabricating an image sensor package according to an embodiment of the invention. The invention will be described with respect to a preferred embodiment of an image sensor package and the fabrication method thereof. The invention may also be applied, however, to any other semiconductor devices.  FIG. 8  is a flow chart of a method for fabricating an image sensor package according to the embodiment of the invention. 
         [0016]    Referring to  FIG. 2 , a substrate  102  made of a material, such as silicon, is provided with an image sensor device  104  and a metal layer  106  thereon, which are electrically connected to each other. In one embodiment, the image sensor device  104  is fabricated on the substrate  102  by a complementary metal-oxide-semiconductor (CMOS) process. Then, the metal layer  106  is formed on the substrate  102  by a metallization process and is electrically connected to the image sensor device  104 . 
         [0017]    In the case, the image sensor device  104  may be complementary metal-oxide-semiconductor device or charge-coupled device (CCD) for capturing pictures or images. The metal layer  106 , preferably, is made of a conductive material such as copper (Cu), aluminum (Al) or tungsten (W). 
         [0018]    Note that while the metal layer  106  illustrated as a signal layer in the embodiments of the invention, the metal layer  106  may also be an interconnection structure comprising of dielectric layers sandwiched between numbers of metal layers, whereby the metal layers are connected to each other by the metal plugs. In one embodiment of the interconnection structure, the bottommost metal layer is directly formed on the substrate and the uppermost metal layer is stacked over the bottommost metal layer to electrically connect the image sensor device and the bottommost metal layer. 
         [0019]    Referring to  FIG. 3 , a covering plate  108  is disposed over the substrate  102 . In some embodiments, a support member  110 , such as epoxy, polyimide (PI), photoresist or any other suitable materials, is formed on the covering plate  108 . Then, an adhesive layer  112  such as a material comprising epoxy is coated on the support member  108  followed by bonding the covering plate  108  to the substrate  102  to form a distance  114  therebetween. Preferably, the covering plate  108  is made of a transparent material such as glass, quartz or any other suitable materials. Additionally, a polymer material such as polyester may also be possible to be used in covering plate  108 . 
         [0020]    Alternatively, the support member  110  may be formed on the substrate  102  followed by coating of the adhesive layer  112  on the support member  110 . Next, the covering plate  108  is bonded to the support member  110  to dispose the covering plate  108  over the substrate  102 . 
         [0021]    After bonding, the substrate  102  is then thinned. In one embodiment, the substrate  102  is ground from its backside by, for example chemical mechanical polishing (CMP) to thin the substrate  102  to an adequate thickness. Preferably, the thickness is less than 150 μm, for example. After thinning, notching the substrate  102  from its backside is executed to form a trench  116  in the substrate  102 , as shown in  FIG. 4 . 
         [0022]    In  FIG. 4 , a trench insulator  122  is formed in the substrate  102 . In some embodiments, etching the backside of the substrate  102  is executed by, for example a dry-etching to form a trench  118  in the substrate  102 , in which the trench  118  surrounds a portion of the substrate  102 . Next, an isolating layer  120 , such as silicon oxide, silicon nitride, silicon oxynitride or any other suitable insulators, is formed on the backside of the substrate  102  and extends to the trench  118  to form the trench insulator  122  which surrounds an isolation region  119 . It is understood that a patterned photoresist (not shown) is formed on the backside of the substrate  102  prior to dry-etching to mask a portion of the substrate  102  and expose the other portion of the substrate  102  for removal. 
         [0023]    In one embodiment, a laser drilling step is also possible to be used in formation of the trench  118  followed by depositing the isolating layer  120  in the trench  118  to form the trench insulator  122  and the isolation region  119 . Note that the isolation region  119  surrounded by the trench insulator  122 , is located in an area below and corresponding to the metal layer  106 . 
         [0024]    Referring to  FIG. 5 , a via hole  128  is formed in the isolation region  119  of the substrate  102 . In one embodiment, a portion of the isolating layer  120 , which covers the isolation region  119 , is removed to expose a surface of the substrate  102  in the isolation region  119 . Next, a hole  124  is formed by, for example dry-etching, laser drilling or any other suitable manners. Thereafter, a conductive layer  126  is formed on the backside of substrate  102  and extends to the hole  124  to form the via hole  128  in electrical connection with the metal layer  106 . Note that the trench insulator  122  surrounds the via hole  128  for isolation. 
         [0025]    In some embodiments, a conductive material layer (not shown), such as aluminum (Al), copper (Cu) or nickel (Ni), is conformally formed on the backside of the substrate  102  and extends to the hole  124  to electrically connect to the metal layer  106  by, for example sputtering, evaporating, electroplating or electroless plating. The conductive material layer is then patterned by photolithography/etching to form the conductive layer  126  and the via hole  128 . Note that a signal conductive path of an image sensor package later formed can be redistributed by the patterning step to the conductive material layer. 
         [0026]      FIG. 6  is a top view of a backside of the semi-finished image sensor package illustrated in  FIG. 5 . In  FIG. 6 , several elements shown in  FIG. 5  are omitted for simple, clear descriptions. Referring to  FIG. 6 , the substrate  102  is divided into several dies through the trench  116 . Each die comprises an image sensor device region  130 , as a dotted line shows in  FIG. 6 , where the image sensor device  104  (shown in  FIG. 5 ) is located. Moreover, the trench insulator  122 , the isolation region  119  and the via hole  128  are located at an area outside of the image sensor region device  130 , in which the trench insulator  122  surrounds the isolation region  119  where the via hole  128  is formed. Specifically, the trench insulator  122  does not only surround the isolation region  119 , but also the via hole  128 . 
         [0027]    Note that although several trench insulators  122  and via holes  128  are shown in  FIG. 6 . In a practical embodiment, however, numerous trench insulators  122  and via holes  128  may surround the image sensor device region  130 . Moreover, geometric shape of the isolation region  119  surrounded by the trench insulator  122 , is a rectangular shape. However, geometric shape of the isolation region  119  may also be a circular shape. In this case, the trench insulator  122  and the via hole  128  are concentric circles. 
         [0028]    Referring to  FIG. 7 , a solder mask  132  is coated on the backside of the substrate  102 , covers the conductive layer  126  and then patterned to expose a portion of the conductive layer  126 . Next, a solder ball  134  is disposed on the conductive layer  126  and further connects to the metal layer  104  by the via hole  128 . In one embodiment, after the solder mask  132  is formed, a solder material (not shown) is coated on the exposed conductive layer  126  followed by performing a reflow step to form the solder ball  134  on the conductive layer  126 . Following the described steps, an individual die is cut out along a predetermined cutting line by a cutter. Thus, an image sensor package  150 , as shown in  FIG. 7 , is complete. Alternatively, a dry-etching step may also be possible to be used in cutting out the individual die. 
         [0029]      FIG. 7  is a cross section of an image sensor package  150  according to an embodiment of the invention. In  FIG. 7 , a substrate  102  is provided with an image sensor device  104  and a metal layer  106  formed thereon. A trench insulator  122  is formed in the substrate  102  and surrounds a portion of the substrate  102  to form an isolation region  119 . Referring to  FIG. 7 , a via hole  128  is formed in the isolation region  119  of the substrate  102 , electrically connecting the metal layer  106  to a solder ball  134 . A covering plate  108  is then disposed over the substrate  102 . 
         [0030]    In the image sensor package according to the embodiment of the invention, because the metal layer connects to the via hole within the isolation region, a signal from the image sensor device is transmitted to an exterior circuit via the metal layer, the via hole and the conductive layer, rather than going around the sidewalls of the substrate to transmit the signal. Thus, a signal conductive path to the image sensor device is shortened. Moreover, because it is unnecessarily to form the conductive layer close to an exterior area of the image sensor package, damage to the conductive layer during fabrication is also reduced, thereby improving fabrication yield. 
         [0031]      FIG. 8  is a flow chart of a method for fabricating an image sensor package according to an embodiment of the invention. Referring to  FIG. 8 , the method comprises: providing a substrate having an image sensor device and a metal layer thereon, as shown in step S 5 ; disposing a covering plate over the substrate, as shown in S 10 ; thinning the substrate, as shown in S 15 ; forming a trench insulator in the substrate, whereby the trench insulator surrounds a portion of the substrate to form an isolation region, as shown in S 20 ; forming a via hole in the substrate within the isolation region, as shown in S 25 ; disposing a solder ball on a backside of the substrate, electrically connected to the image sensor device through the via hole, as shown in S 30 ; and complete an image sensor package by dicing, as shown in S 35 . 
         [0032]    Note that because the substrate is thinned, the overall thickness of the image sensor package is reduced. Thus, the image sensor package according to the embodiment of the invention has relatively small dimensions. Moreover, because extra steps, such as the attaching step for bonding a chip to a carrying plate or the etching step for separating the chip are not required, fabrication of the image sensor package is simplified and costs are reduced. 
         [0033]    While the invention has been described by way of example and in terms of preferred embodiment, it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.