Abstract:
A biochip package structure is provided. The biochip package structure includes a substrate, a biochip, at least one wire, and a molding compound. The substrate has a circuit unit electrically connected, by wiring, to the biochip defined with a sensing region. The molding compound covers the wire but leaves the sensing region of the biochip exposed, allowing a cavity to be formed in the sensing region. The cavity delivers a biomedical sample. The biomedical sample reacts in the sensing region. Thus, the biochip package structure is applicable to various medical and biochemical assays.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Technical Field 
         [0002]    The present invention relates to a biochip package structure, and more particularly, to a biochip package structure capable of delivering a biomedical sample to a biochip therein. 
         [0003]    2. Description of Related Art 
         [0004]    A biochip refers to a bioassay element, based on principles of molecular biology and biochemistry, having a substrate made of glass or polymer materials, and incorporating therewith the micro-electro-mechanical technology. Such biochip features for its compact size as well as excellent ability in prompt and parallel processing and thus allows a large scale of bioassay to be accomplished in a minute area. A micro-fluidic channel provided on such biochip accommodates procedures for processing a biomedical sample, such as mixing, transmitting and segregating. By using a biochip having a micro-fluidic channel, advantages, including reducing experimental errors owing to human operation, minimizing consumption of energy and biomedical samples, and saving labor as well as time, can be achieved. 
         [0005]      FIG. 1  is a cross-sectional view of a conventional biochip package structure having a micro-fluidic channel. 
         [0006]    Referring to  FIG. 1 , a conventional biochip package structure is constructed by steps of using a polymer material to build a three-dimensional rail  21  and adhering the rail  21  onto a biochip  10  so as to form a micro-fluidic channel  20  on the biochip  10 . Besides the area occupied by the rail  21 , the biochip  10  has to reserve area for the dispensing process where a molding compound  30  is formed on the biochip  10 . Consequently, the effective area of the biochip  10  is significantly limited and thus the overall working efficiency of the biochip  10  is adversely affected. 
         [0007]    The prefabricated rail  21 , for convenient attachment to the biochip  10 , is sized according to the biochip  10  and thus provides a relatively limited capacity for accommodating biomedical samples. Consequently, due to insufficiency of the biomedical sample in the micro-fluidic channel  20 , the biochip  10  is likely to give inaccurate testing results. 
         [0008]    Besides, electronic packaging effect of the biochip  10  provided by the molding compound  30  formed through the dispensing process is relatively inferior. Hence, there is a need for an approach that forms the micro-fluidic channel  20  on the biochip  10  with maximized effective area and improved electronic packaging effect of the biochip  10 , so as to further expand applications of the biochip  10 . 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention discloses a biochip package structure, wherein a micro-fluidic channel is formed on a biochip, and an increased contacting area between the micro-fluidic channel and the biochip is provided, thereby enhancing overall working efficiency of the biochip. 
         [0010]    The present invention also discloses a biochip package structure, which has a cavity for delivering a biomedical sample so as to easily control consumption of the biomedical sample. 
         [0011]    To achieve these and other objectives of the present invention, the disclosed biochip package structure includes a substrate with a circuit unit, a biochip coupled to the substrate and defined with at lease one sensing region, at least one wire electrically connecting the circuit unit and the biochip, and a molding compound for covering the wire but leaving the sensing region exposed so as to form a cavity in the sensing region. 
         [0012]    By implementing the present invention, at least the following progressive effects can be achieved: 
         [0013]    1. The relatively large contacting area between the biochip and a biomedical sample delivered thereon improves overall working efficiency of the biochip. 
         [0014]    2. The cavity is capable of delivering the biomedical sample in a relatively large amount and therefore conducive to accurate bioassay results. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    The invention as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein: 
           [0016]      FIG. 1  is a cross-sectional view of a conventional biochip package structure having a micro-fluidic channel; 
           [0017]      FIG. 2  is an exploded view of a biochip package structure according to a first embodiment of the present invention; 
           [0018]      FIG. 3  is an assembled perspective view of the biochip package structure of  FIG. 2 ; 
           [0019]      FIG. 4  is a cross-sectional view taken along line A-A of  FIG. 3 ; 
           [0020]      FIG. 5A  is a cross-sectional view of the biochip package structure according to one aspect of the first embodiment of the present invention; 
           [0021]      FIG. 5B  is a cross-sectional view of the biochip package structure according to another aspect of the first embodiment of the present invention; 
           [0022]      FIG. 6A  is an exploded view of a biochip package structure according to a second embodiment of the present invention; 
           [0023]      FIG. 6B  is an assembled perspective view of the biochip package structure of  FIG. 6A ; 
           [0024]      FIG. 7A  is a cross-sectional view taken along line B-B of  FIG. 6B ; 
           [0025]      FIG. 7B  is an applied view of the biochip package structure of  FIG. 7A ; 
           [0026]      FIG. 8A  is a cross-sectional view of the biochip package structure according to another aspect of the present invention; and 
           [0027]      FIG. 8B  is an applied view of the biochip package structure of  FIG. 8A . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0028]    Referring to  FIG. 2 , the present embodiment relates to a biochip package structure  100 , which includes a substrate  11 , a biochip  10 , at least one wire  12 , and a molding compound  30 . 
         [0029]    The substrate  11  is formed with a circuit unit  13 . The substrate  11  may be a circuit board, a glass substrate, or a substrate made of LTCC (Low-Temperature Cofired Ceramics), a biocompatible material or other materials meeting required circuit characteristics. 
         [0030]    The biochip  10  is coupled to the substrate  11  and defined with at lease one sensing region  14 . The biochip  10  is a chip applicable to bioassay for medical or biochemical purposes. For instance, by using the micro-electro-mechanical technology, a CMOS (Complementary Metal-Oxide-Semiconductor) may be equipped with at least one said sensing region  14  made of metal so as to allow bio-molecules to be bound and fixed by the sensing region  14 , thereby permitting bioassay on the bio-molecules. Functions of the sensing region  14  on the biochip  10  may include reading genetic sequence, analyzing protein composition, measuring pH, etc. 
         [0031]    The wire  12  electrically connects the circuit unit  13  of the substrate  11  and the biochip  10 . The wire  12  is made of gold, aluminum, copper or alloy thereof. 
         [0032]    As shown in  FIGS. 2 and 3 , the molding compound  30  covers each said wire  12  but leaves the sensing region  14  exposed so as to form a cavity  31  in the sensing region  14 . The molding compound  30  is made of epoxy resin or other materials generally used for IC package. Also, the molding compound  30  is formed by an injection molding process so as to enhance packaging efficiency of the biochip package structure  100 . Moreover, an input hole  32  and an output hole  33  are formed at two ends of the cavity  31 , respectively. 
         [0033]    Referring to  FIG. 4 , the exposed sensing region  14  is configured to be in direct contact with a biomedical sample thereon. Therefore, upon passage of a biomedical sample through the cavity  31 , the sensing region  14  reacts with the biomedical sample. The wire  12  connecting the biochip  10  and the substrate  11  is covered by the molding compound  30  and thus is protected from being damaged by moisture. 
         [0034]    Referring to  FIG. 5A , the biochip package structure  100  further includes a cover  40  fixed in position to the molding compound  30  and facing the biochip  10 . Since the cover  40  fully covers the cavity  31 , a micro-fluidic channel  20  is formed in the biochip package structure  100 . 
         [0035]    Referring to  FIG. 5A  again, the cover  40  is made of a material that is penetrable to light so that the biochip package structure  100  is allowed to be used with an optical inspection system, such as, for analyses of fluorescent labels. 
         [0036]    Alternatively, as shown in  FIG. 5B , the cover  40  is made of a material that is impenetrable to light. After flowing into the biochip package structure  100  through the input hole  32 , the biomedical sample is led to the sensing region  14  of the biochip  10  and eventually leaves the biochip  10  at the output hole  33 . The cover  40  is made of a biocompatible material, such as polydimethylsiloxane (PDMS) or polymethylmethacrylate (PMMA). Optionally, a material of which the cover  40  is made is flexible too. 
         [0037]    Regarding the micro-fluidic channel  20  defined by the cover  40  of the biochip package structure  100 , the micro-fluidic channel  20  is capable of accommodating obviously a larger amount of a biomedical sample than that receivable in a micro-fluidic channel  20  of a conventional biochip package structure. Hence the accuracy of bioassay results obtained through the biochip package structure  100  of the present invention is improved, thereby avoiding erroneous determination. Meanwhile, consumption of the biomedical sample can be easily controlled. 
         [0038]    Unlike a conventional cover  40  which is in contact with a micro-fluidic channel  20  of a biochip  10  and thus reduces the effective area of the biochip  10 , the cover  40  of the present invention is fixed upon the molding compound  30  without contacting the biochip  10 . Consequently, the micro-fluidic channel  20  defined by the cover  40  facilitates maximizing the effective area of the biochip  10  and thus enhancing the overall working efficiency of the biochip  10 . 
         [0039]    Referring now to  FIGS. 6A and 6B , the biochip package structure  100  further comprises a micro-fluidics driving unit  50  attached to the cover  40  and configured to adjust flow rate of the biomedical sample introduced into the micro-fluidic channel  20  so as to allow the biomedical sample to pass through the sensing region  14  of the biochip  10  with a constant flow rate. Particularly, the micro-fluidics driving unit  50  is a pneumatic micro-pump  501 . 
         [0040]    Referring to  FIG. 7A , the pneumatic micro-pump  501  is attached to the cover  40  to form a high-pressure gas channel  502 . Referring to  FIG. 7B , since the cover  40  is flexible, when the high-pressure gas channel  502  is fed with gas, the cover  40  sags under the gas pressure and thereby stops the biomedical sample in the micro-fluidic channel  20  below the cover  40  from flowing. After the gas passes the high-pressure gas channel  502 , the cover  40  recovers its initial status and therefore the biomedical sample in the micro-fluidic channel  20  is allowed to flow forward again. By using the pneumatic micro-pump  501 , it is possible to adjust gas pressure in the high-pressure gas channel  502  or the frequency where the gas passes through the high-pressure gas channel  502  in order to control the frequency of sagging of the cover  40  and thus push the biomedical sample forward, thereby controlling the flow rate of the biomedical sample in the micro-fluidic channel  20 . 
         [0041]    Referring to  FIG. 8A , alternatively, the micro-fluidics driving unit  50  is a piezoelectric micro-pump  503  that includes a piezoelectric actuator and is attached to the cover  40  by means of, for example, a peripheral fixing manner. 
         [0042]    By adjusting electric field strength of the piezoelectric micro-pump  503 , the cover  40  sags under the control of the piezoelectric micro-pump  503 , as shown in  FIG. 8B , and in turn varies inner space of the micro-fluidic channel  20 . Similarly, the piezoelectric micro-pump  503  also serves to bulge the cover  40  (not shown). 
         [0043]    Therefore, by using the piezoelectric micro-pump  503 , it is possible to adjust the flow rate of the biomedical sample in the micro-fluidic channel  20  and thus distribute the biomedical sample in the micro-fluidic channel  20  more evenly. 
         [0044]    Although the particular embodiments of the invention have been described in detail for purposes of illustration, it will be understood by one of ordinary skill in the art that numerous variations will be possible to the disclosed embodiment without going outside the scope of the invention as disclosed in the claims.