Abstract:
Package for an integrated circuit (IC), includes a housing ( 3 ) of a first material having two major surfaces ( 4, 5 ). The major surfaces are substantially parallel to each other. Furthermore, a lead frame ( 6 ) is present for carrying the IC ( 2 ), the lead frame ( 6 ) including contact terminals ( 7 ) for electrical communication with the IC ( 2 ). The package ( 1 ) has a through-hole ( 8 ) in the two major surfaces ( 4, 5 ), allowing various special applications of the package ( 1 ).

Description:
FIELD OF INVENTION  
       [0001]    The present invention relates to a package for an integrated circuit (IC), said package comprising;
       a housing of a first material, having two major surfaces, which are substantially parallel to each other,   a lead frame for carrying the IC, the lead frame comprising outside contact terminals for electrical communication with the IC.       
 
       BACKGROUND  
       [0004]    Such a package is known from e.g. PCT patent application WO2004/086003 wherein a method and assembly are shown, the method including the steps of providing a coated or uncoated sensor element having an exposed sensing surface; attaching the sensor element to a platform so that the exposed sensing surface is spaced from the platform; and optionally applying a protective layer over the platform while maintaining the sensing surface as exposed. The assembly includes a resonator having a free portion with a sensing surface incorporated onto a platform, components of the sensor are physically shielded from harsh operating conditions, the requisite space is maintained between the free portion of the resonator and the platform, and the sensing surface of the resonator remains exposed for sensing. The assembly may include a cut-out through which the sensor is exposed to ambient environment. This known package offers a very limited design freedom and a limited possible interaction between sensor and media to be sensed. 
       SUMMARY OF THE INVENTION  
       [0005]    The invention aims to provide an improved package with a predetermined shape and well defined dimensions. 
         [0006]    According to a first aspect of the invention a package for an integrated circuit (IC) is provided, said package comprising;
       a housing of a first material, having two major surfaces, which are substantially parallel to each other,   a lead frame for carrying the IC, the lead frame comprising outside contact terminals for electrical communication with the IC,       
 
         [0009]    wherein the package comprises a through-hole in the two major surfaces. This hole can have any shape like round, rectangular, square, oval etc. The material of the housing can be a resin which is UV or temperature cured for hardening. 
         [0010]    This provides a design freedom to enable access through the package, possibly in combination with a hole in the substrate and/or printed circuit board. This package may be used to enable a sensor surface of an electronic component to communicate with a fluid. 
         [0011]    In an embodiment of the package according to the invention, the longitudinal axis of said through-hole is substantially perpendicular to said major surfaces. This simplifies the manufacturing process of the package and allows maximum possible access to the through-hole. 
         [0012]    In an embodiment of the package according to the invention, the package further comprises an electronic component in said through-hole which is e.g. mechanically attached to an outline of said through-hole. This electronic component can be an ASIC, a sensor etc. that extends into the through-hole space. 
         [0013]    In an embodiment of the package according to the invention, the electronic component comprises a sensor surface, possibly in the through hole, enabling a fluid access to a sensing surface of said sensor to measure various parameters of the fluid, like pressure, viscosity etc. The sensor surface is e.g. shaped as a tuning fork, as used in piezo flow sensors. 
         [0014]    In an embodiment of the package according to the invention, a first portion of said electronic component is encapsulated by said housing. This protects the portion of the electronic component against possibly aggressive fluids and improves the robustness of the system. 
         [0015]    In an embodiment of the package according to the invention, said electronic component comprises electrical contact members, like outside contact terminals for electrical contact with the IC. When provided on said first portion of the electronic component, these contacts are protected by the housing. 
         [0016]    In an embodiment of the package according to the invention, the package further comprises a ring member having an opening possibly congruent with the through-hole. This gives a designer a freedom with to respect to e.g. material choice, dimensions etc. in the interface area of the electronic component and the fluid. The ring member may be premoulded or manufactured otherwise. 
         [0017]    In an embodiment of the package according to the invention, said ring member is of a second material. This can be a thermoplastic material, though it can be duroplast as well. 
         [0018]    In an embodiment of the package according to the invention, said first material and said second material are different. 
         [0019]    In an embodiment of the package according to the invention, said ring member is a carrier for carrying said electronic component. The ring member and the electronic component may be affixed and handled a sub-assembly. 
         [0020]    The invention further relates to an assembly of a package according to any one of the preceding claim and a carrier element, in which the carrier element comprises a second through-hole coaxial with said through-hole in the package. 
         [0021]    The invention further relates to a method of packaging an electronic component, the method comprising; 
         [0022]    mechanically affixing said electronic component and a ring member, 
         [0023]    electronically connecting electrical contact members provided on said electronic component, 
         [0024]    encapsulate a first portion of said ring member, said portion carrying said electrical contact members of electronic component. Applying of this method offers the advantage of a package wherein contact members are protected by the encapsulation. 
         [0025]    In an embodiment of the method according to the invention, the method further comprises; 
         [0026]    moulding of said ring member. This results in a ring member with a well defined shape en dimensions and consequently a good basis for a proper positioning of the electronic component. 
         [0027]    The various aspects discussed in this patent can be combined in order to provide additional advantageous advantages. 
     
    
     
       DESCRIPTION OF THE DRAWINGS  
         [0028]    The invention will be further elucidated referring to an preferred embodiment shown in the drawing wherein shown in: 
           [0029]      FIG. 1  in top view a package according to the invention; 
           [0030]      FIG. 2  a side view of a cross section of the package according to  FIG. 1 ; 
           [0031]      FIG. 3  a side view of a cross section of the package according to  FIG. 1  assembled on a printed circuit board; 
           [0032]      FIG. 4   a  in top view a package and a ring member; 
           [0033]      FIG. 4   b  a side view of a cross section of the package according to  FIG. 4   a;    
           [0034]      FIG. 5   a  top view of a package with an electronic component in the hole; 
           [0035]      FIG. 5   b  a side view of a cross section of the package according to  FIG. 5   a;    
           [0036]      FIG. 6  a side view of a cross section of a package with a sensor extending over all through-hole. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS  
       [0037]    In  FIG. 1  and  FIG. 2  a first embodiment of the package  1  according to the invention is shown.  FIG. 3  shows a first embodiment with a package  1  assembled on a carrier element  16 , such as a printed circuit board  16 . The package  1  for protecting an IC  2  comprises a housing  3  having two major surfaces  4 ,  5  which are substantially plan parallel to each other. The housing  3  contains a lead frame  6 . This lead frame  6  carries the IC  2  and any other desired component. Contact pads of the IC  2  are electrically connected to the lead frame  6  by e.g. wire-bonding. Outside contact terminals  7  are electrically connected via the lead frame  6  with the IC  2 . Extremities of contact terminals  7  all lie in a plane substantially parallel to the major surfaces  4 ,  5 . In the embodiment shown in  FIGS. 1-3  the package  1  is provided with a through-hole  8  with a rectangular shape. Other shapes are possible for the through-hole  8  like a circle, oval square etc. The longitudinal axis  9  of the through-hole  8  is substantially perpendicular to the major surfaces  4 ,  5  of the package  1 . The outline of the through-hole  8  is bevelled or inclined with respect to the major surfaces  4 ,  5  so that a chamfer  18  is provided. This chamfer  18  simplifies fitting e.g. a tube in the through-hole  8 . In  FIG. 3  package  1  is mounted on a printed circuit board  16 . This printed circuit board  16  is provide with a through-hole  17 . In this embodiment the through-hole  8  and the through-hole  17  are coaxial, though other arrangements are possible as well. This first embodiment offers design freedom by providing access through the package and possibly through the printed circuit board as well. One may lead a fluid through the hole, move a body through the hole or lead conductors like a wire or a flat cable through the hole. 
         [0038]    In  FIG. 4   a  and  4   b  a second embodiment of the package according to the invention is shown. The package  1  for protecting an IC  2  comprises a housing  3  having two major surfaces  4 ,  5  which are substantially plan parallel to each other. The housing  3  contains a lead frame  6 . This lead frame  6  carries the IC  2  and any other desired component. Contact pads of the IC  2  are electrically connected to the lead frame  6  by e.g. wire-bonding. Outside contact terminals  7  are electrically connected via the lead frame  6  with the IC  2 . Extremities of contact terminals  7  all lie in a plane substantially parallel to the major surfaces  4 ,  5 . The package  1  is provided with a through-hole  8  with a rectangular shape. Other shapes are possible for the through-hole like a circle, oval square etc. At the outline of the through-hole  8 , a chamfer  18  is provided. This chamfer  18  simplifies fitting e.g. a tube in the through-hole  8 . The package  1  is further provided with a ring member  10  arranged in through-hole  8 . The shape of this ring member  10  or insert  10  is congruent with the shape of the through-hole  8 . The ring-member  10  itself is provided with a through-hole  11  as well. In this embodiment the shape of through-hole  11  is congruent with the shape of through-hole  8  in the package  1 , though other shapes are possible as well. In  FIG. 4   b  it is shown that ring member  10  extends into housing  3  and is firmly held by housing  3 . This can be achieved by e.g. pre-moulding the ring member  10 , insert this member in the package tooling and encapsulate the ring member  10  in the housing  3 . The housing  3  comprises a first material like e.g. a duroplast while the ring member  10  comprises a second material. The second material may be a softer material than the first material so that the ring member  10  is clamped by the housing  3 . In this embodiment the lead frame  6  extends into the ring member  10 . Using a ring member  10  offers even more design freedom with respect to material choice and shape. The ring member  10  may be adapted for a certain application and provide a connection like for instance a snap joint. The material choice of the ring member  10  may be tailored to a certain fluid. 
         [0039]      FIG. 5   a - 5   b  and  FIG. 6  show a third embodiment of the package according to the invention. The package  1  for protecting an IC  2  comprises a housing  3  having two major surfaces  4 ,  5  which are substantially plan parallel to each other. The housing  3  contains a lead frame  6 . This lead frame  6  carries the IC  2  and any other desired component. Contact pads of the IC  2  are electrically connected to the lead frame  6  by e.g. wire-bonding. Outside contact terminals  7  are electrically connected via the lead frame  6  with the IC  2 . Extremities of contact terminals  7  all lie in a plane substantially parallel to the major surfaces  4 ,  5 . The package  1  is provided with a through-hole  8  with a rectangular shape. Other shapes are possible for the through-hole like a circle, oval square etc. At the outline of the through-hole  8 , a chamfer  18  is provided. This chamfer  18  simplifies fitting e.g. a tube in the through-hole  8 . The package  1  is further provided with a ring member  10  arranged in through-hole  8 . The shape of this thin-walled ring member  10  or insert is congruent with the shape of the through-hole  8 . The ring-member  10  itself is provided with a through-hole  11  as well. In this embodiment the shape of through-hole  11  is congruent with the shape of through-hole  8  in the package  1 , though other shapes are possible as well. In  FIG. 4   b  it is shown that ring member  10  extends into housing  3  and is firmly held by housing  3 . This can be achieved by e.g. pre-moulding the ring member  10 , insert this member in the package tooling and encapsulate the ring member  10  with e.g. a duroplast material. 
         [0040]    In this embodiment the lead frame  6  extends into the ring member  10 . In the through-hole  8  there is provided an electronic component  12  like e.g. a sensor with a sensor surface  13 . When this sensor surface  13  is in fluid connection with a fluid, parameters like pressure, viscosity, conductivity, type of material, concentration etc. can be measured and IC  2  can process the sensor signal. The electronic component  12  is attached to or held in position by ring member  10 , housing  3  as well as lead frame  6 . Electrical contact members  15  or contact pads  15  of electronic component  12  are provided on a first portion  14  of the electronic component  12 . This first portion  14  is encapsulated in the housing  3  so that the contact pads  15  are protected against exposure to e.g. aggressive fluids. The contact pads  15  are electrically connected tot the IC  2  using e.g. wire-bonding such that IC  2  can process the sensor signal. 
         [0041]      FIG. 5   a  and  5   b  show an electronic component  12  that extends over a part of through-hole  8 . The electronic component  12  may even extend over all through-hole  8 . 
         [0042]      FIG. 6  shows the electronic component  12  may even cover the entire cross section of the through-hole  8 . The electronic component  12  may even close through-hole  8 . This embodiment provides a robust integration of an electronic component, like a sensor, at the through-hole of the package offering all sorts of interaction with and exposure to e.g. a fluid. 
         [0043]    It will also be obvious after the above description and drawings are included to illustrate some embodiments of the invention, and not to limit the scope of protection. Starting from this disclosure, many more embodiments will be evident to a skilled person which are within the scope of protection and the essence of this invention and which are obvious combinations of prior art techniques and the disclosure of this patent.