Abstract:
An apparatus and method for manufacturing a micro-electrical mechanical system (MEMS) package comprising a first molded body having a first acoustic port, a second molded body connected to the first molded body, a leadframe at least partially integral with at least one of the first and second molded bodies, a die cavity provided on at least one of the first and second molded bodies and having a second acoustic port, a MEMS die provided on the die cavity, a channel connecting the first and second acoustic ports, the first molded body sealing at least a portion of the channel, and a lid attached to the second molded body and sealing at least a portion of the die cavity.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to an apparatus and method for manufacturing a MEMS package. 
       DISCUSSION OF THE RELATED ART 
       [0002]    In high-performance acoustic MEMS devices, signals are transmitted via a continuous closed medium to the membrane at the die level. In the marketplace today, consumers demand ever thinner MEMS packages. Current MEMS packages are manufactured using multiple layers of FR 4 or similar material to create these packages. This is a slow and expensive process. Each layer must be separately manufactured with specific conductive patterns, and painstakingly machined to create the desired openings. Each layer is then laminated together to create the finished package. Using such a method, it takes between five and ten weeks to manufacture 500,000 MEMS packages. 
         [0003]      FIG. 1  illustrates an example of a molded integrated circuit package  100 . While molding technology has been adapted in the field of integrated circuits to create integrated circuit packages more efficiently, integrated circuit molding technology does not lend itself to acoustic MEMS packages. Unlike the integrated circuit package shown in  FIG. 1 , acoustic MEMS packages typically include at least one acoustic port and channel, which is enclosed within the package for sound isolation purposes. Creating an acoustic channel typically takes multiple steps and requires use of an insert to form the channel in the mold. In conventional moldings, any inserts  102  used to form cavities  104  in the circuit package  100  would remain inside, making removal of the insert  102  difficult or impossible. Accordingly, a need exists for an apparatus and method for forming an integrated molded acoustic MEMS package. 
       SUMMARY OF THE INVENTION 
       [0004]    The present invention is directed to an apparatus and method for manufacturing a MEMS package. 
         [0005]    Embodiments of the invention provide an apparatus and method for manufacturing a micro-electrical mechanical system (MEMS) package comprising a molded body, a printed circuit board at least partially integral with the molded body, a leadframe connected to the molded body, a die cavity provided on the leadframe and having a first acoustic port, a MEMS die provided on the die cavity, a lid connected to the leadframe and having a second acoustic port, the lid sealing at least a portion of the die cavity, and a channel connecting the first and second acoustic ports, the lid sealing at least a portion of the channel. 
         [0006]    Another exemplary embodiment of the invention provides an apparatus and method for manufacturing a MEMS package comprising a molded body, a first printed circuit board at least partially integral with the molded body, a second printed circuit board connected to the molded body, a die cavity provided on at least one of the first and second printed circuit boards and having a first acoustic port, a MEMS die provided on the die cavity, a lid connected to at least one of the first and second printed circuit boards and having a second acoustic port, the lid sealing at least a portion of the die cavity, and a channel connecting the first and second acoustic ports, the lid sealing at least a portion of the channel. 
         [0007]    Another exemplary embodiment of the invention provides an apparatus and method for manufacturing a MEMS package comprising a molded body having a first acoustic port, conductive traces applied to the molded body, a die cavity provided on the molded body and having a second acoustic port, a MEMS die provided on the die cavity, a channel connecting the first and second acoustic ports, a first lid attached to the molded body and sealing at least a portion of the channel, and a second lid attached to the molded body and sealing at least a portion of the die cavity. 
         [0008]    Yet another exemplary embodiment of the invention provides an apparatus and method for manufacturing a MEMS package comprising a molded body having a first acoustic port, a leadframe at least partially integral with the molded body, a die cavity provided on the molded body and having a second acoustic port, a MEMS die provided on the die cavity, a channel connecting the first and second acoustic ports, a first lid attached to the molded body and sealing at least a portion of the channel, and a second lid attached to the molded body and sealing at least a portion of the die cavity. 
         [0009]    Still another exemplary embodiment of the invention provides an apparatus and method for manufacturing a MEMS package comprising a first molded body having a first acoustic port, a second molded body connected to the first molded body, a leadframe at least partially integral with at least one of the first and second molded bodies, a die cavity provided on at least one of the first and second molded bodies and having a second acoustic port, a MEMS die provided on the die cavity, a channel connecting the first and second acoustic ports, the first molded body sealing at least a portion of the channel, and a lid attached to the second molded body and sealing at least a portion of the die cavity. 
         [0010]    It should be understood that both the foregoing general description and the following detailed description are exemplary and explanatory, and intended to provide further explanation of the invention as claimed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The accompanying drawings, included to provide a further understanding of the invention, are incorporated in and constitute a part of this specification. They illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings: 
           [0012]      FIG. 1  illustrates an example of an injection molded integrated circuit; 
           [0013]      FIG. 2A  illustrates an exemplary embodiment of a through-etched frame array in accordance with the present invention; 
           [0014]      FIG. 2B  illustrates a close-in view of the exemplary embodiment of a through-etched frame array in  FIG. 2A ; 
           [0015]      FIG. 3A  illustrates an exemplary embodiment of a through-etched frame molded body array in accordance with the present invention; 
           [0016]      FIG. 3B  illustrates a top view of an exemplary embodiment of a through-etched frame molded body in accordance with the present invention; 
           [0017]      FIG. 3C  illustrates a bottom view of an exemplary embodiment of a through-etched frame molded body in accordance with the present invention; 
           [0018]      FIG. 4A  illustrates an exemplary embodiment of a partially-etched frame in accordance with the present invention; 
           [0019]      FIG. 4B  illustrates a cutaway view of an exemplary embodiment of a partially-etched frame in accordance with the present invention; 
           [0020]      FIG. 4C  illustrates a bottom view of an exemplary embodiment of a partially-etched frame in accordance with the present invention; 
           [0021]      FIG. 4D  illustrates a close-in view of an exemplary embodiment of an integrally molded partially-etched frame in accordance with the present invention; 
           [0022]      FIG. 4E  illustrates a top view of a molded body array with a partially-etched frame in accordance with the present invention; 
           [0023]      FIG. 5A  illustrates a double-body MEMS package with a frame and thin PCB over-mold in accordance with the present invention; 
           [0024]      FIG. 5B  illustrates a double-body MEMS package with an upper PCB and lower thin PCB over-mold in accordance with the present invention; 
           [0025]      FIG. 6A  illustrates an exemplary embodiment of a plated molded body in accordance with the present invention; 
           [0026]      FIG. 6B  illustrates a top view of an exemplary embodiment of a plated molded body with plated conductive traces and vias in accordance with the present invention; 
           [0027]      FIG. 6C  illustrates a bottom view of an exemplary embodiment of a plated molded body with plated conductive traces and vias in accordance with the present invention; 
           [0028]      FIGS. 7A-7D  illustrate an exemplary embodiment of a single-body leadframe MEMS package assembled in accordance with the present invention; 
           [0029]      FIG. 7E  illustrates a cutaway view of an exemplary embodiment of a single-body molded leadframe assembly in accordance with the present invention; 
           [0030]      FIG. 8  illustrates an exemplary embodiment of a single-body MEMS package with a bottom acoustic port in accordance with the present invention; 
           [0031]      FIG. 9A  illustrates a top view of an exemplary embodiment of a double-body bottom lid in accordance with the present invention; 
           [0032]      FIG. 9B  illustrates a bottom view of an exemplary embodiment of a double-body bottom lid in accordance with the present invention; 
           [0033]      FIG. 10A  illustrates an exemplary embodiment of a double-body MEMS package with a top acoustic port in accordance with the present invention; and 
           [0034]      FIG. 10B  illustrates an exemplary embodiment of a double-body MEMS package with a bottom acoustic port in accordance with the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0035]    The present invention provides a thin package profile relative to commercially available MEMS packages, reliably manufactured in high volume at low cost. The overall thickness of MEMS packages is dictated by a number of factors, including back volume/transducer interrelationships, material tolerances, and wiring/lead placement. For example, the back volume of a MEMS package cannot be appreciably reduced to thereby reduce the overall thickness of the package due to, at least, calibration of the transducer in the MEMS package. 
         [0036]    Overall MEMS package thickness can be significantly reduced by (1) at least partially integrating the metal circuit frame into the mold of the MEMS package and/or (2) eliminating a prefabricated conductive frame altogether and replacing the frame with a thin-core PCB over-mold or plating a conductor in an appropriate shape directly onto a mold body. As used herein, the term “integral” means that at least a portion of one layer of a component extends at least partially into a layer of another component. 
         [0037]    In accordance with the present invention, an apparatus (e.g., a package) and method for manufacturing a MEMS package are disclosed. In certain embodiments, the package can include a double-body or single-body design. In one exemplary embodiment of a double-body design, a leadframe is at least partially integral with a substrate (e.g., a molded body). In exemplary embodiments where the leadframe is at least partially integral with a substrate, the frame can be through-etched or partially-etched (e.g., half) to reduce the overall thickness of the MEMS package and frame combination, by virtue of the fact that both the substrate and frame are at least partially in the same layer. In another embodiment of a double-body design, a printed circuit board (PCB) is used in place of a frame, with the body over-molded onto the printed circuit board. This is called a thin-core PCB over-mold MEMS package. Replacing the frame with a printed circuit board further reduces the thickness of the MEMS package. In another embodiment of a double-body design, conductors can be on a mold surface. Such embodiments include plating of a conductor directly on the mold body. Because the leadframe does not need to be machined in such embodiments, these embodiments significantly reduce the overall thickness of the package by reducing the thickness of the leadframe to a minimum, with plating as thin as about 8 um being possible. 
         [0038]    Reference will now be made in detail to the exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings. 
         [0039]    I. Frame Integral with a Molded Body 
         [0040]    As discussed above, in certain embodiments, a frame, and in certain embodiments, an electrically conductive frame, is at least partially integrated with a substrate over-mold by either through etching or partial etching. This section describes exemplary embodiments of through-etched and partially-etched frames in accordance with the present invention. 
         [0041]    A. Through-Etched Design 
         [0042]    Through-etched frames are frames where at least a portion of the frame is etched or stamped completely through. For ease of reference, unless otherwise noted, “stamped” and “through-etched” are collectively referred to as “through-etched.” The through-etched design includes a package substrate and method of fabrication. Exemplary embodiments of each are described hereafter. 
         [0043]    1. Through-Etched Frame Integral with a Molded Body 
         [0044]      FIG. 2A  illustrates an exemplary embodiment of an array  202  of through-etched frames  204  in accordance with the present invention. Each through-etched frame is approximately 150 um thick. The size and shape of the array  202  is exemplary only, and not limited to what is shown. 
         [0045]    Forming frames and other parts in an array enables high-volume production of MEMS package components. High-volume production is defined as the production of millions of units per month, and applies to any embodiment described herein. In certain embodiments, approximately four million units or more can be produced per month. 
         [0046]    In an array, individual components such as the through-etched frames  204  of the exemplary embodiment of the invention in  FIG. 2A  may be held together by connecting ribs  212  or supporting material (not shown) that may be removed after production. Other MEMS package components may also be manufactured in an array. Once the components are produced in an array, they may be singulated (i.e., separated from an array) using laser marking or other processes known to those skilled in the art. The components may be singulated before assembly, or manufactured as an array and then singulated. While the frame is shown as part of an array, in other exemplary embodiments, through-etched frames  204  may be manufactured individually. 
         [0047]    In the through-etched frame  204  shown in  FIG. 2A , the openings  206  may be etched through or, alternatively, they may be stamped through. In the exemplary embodiment shown, each through-etched frame  204  has interconnect posts  208  for electrically and/or mechanically connecting with other components. The number, shape, and size of the openings  206  and interconnect posts  208  are exemplary only, and not limited to what is shown. While the frames shown in the exemplary embodiment of  FIGS. 2A and 2B  are metal frames, other embodiments may have frames that are at least partially non-metallic. In other embodiments, the frame may be at least partially conductive, and may have one or more conducting layers (not shown). In frames with at least one conducting layer, such as the frame  204  of the exemplary embodiment shown in  FIGS. 2A and 2B , connections among conducting layers may be through vias (not shown). Vias may be solid or at least partially hollow. They may be formed by any method known to those skilled in the art, including but not limited to use of conductive epoxy, metal inserts, conducting fillers, solder, or metal deposition. Vias are discussed in greater detail in the description of the exemplary embodiment of the invention shown in  FIGS. 3A-3C . 
         [0048]      FIG. 2B  shows a close-in view of the interconnect posts  208  of  FIG. 2A . The number, shape, and location of the interconnect posts  208  are exemplary only, and not limited to what is shown. In the embodiment of  FIGS. 2A and 2B , the posts  208  are at least partially conductive, and may function as vias for connecting to a substrate (not shown). The interconnect posts  208  may be integrally molded with the frame  204 . The interconnect posts  208  may be created through etching, metal deposition, solder, conductive paste, or other methods known to those skilled in the art. Manufacturing the posts  208  at the same time as the frame  204  eliminates the requirement for forming plated or solid conductive vias (not shown) in a molded body substrate, since the interconnect posts  208  may be used for conducting. Again, vias are discussed in more detail in the description of the embodiment of the invention shown in  FIGS. 3A-3C . 
         [0049]    2. Through-Etched Frame Molded Package 
         [0050]      FIGS. 3A-3C  show an exemplary embodiment of the invention with a through-etched frame  304  formed as an integral part of the molded body  306  of a MEMS package. Molding is preferable to the related art method of layering FR-4 substrates because it enables better control of dimensional tolerances such as, for example, acoustic channel dimensional tolerances. Molding the molded body  306  integrally with the through-etched frame  304  also simplifies the production process. In contrast with conventional molding technology, where removal of an insert (not shown) used to form an acoustic channel is difficult or impossible, molding the molded body  306  integrally with the frame enables easy removal of inserts. 
         [0051]      FIG. 3A  shows an array  302  of through-etched frames  304  after they have been at least partially integrally molded with a molded body  306 . Using conventional technology, the frame would have been stacked onto a substrate. In contrast to conventional technology, once the through-etched frames  304  of the invention are formed, they are placed into a mold of a desired shape (not shown), and molding compound (not shown) is added to the mold to create a substrate that is at least partially integrally molded with the through-etched frame  304 . The molding compound may be comprised of one or more of a liquid crystal polymer (LCP), thermoplastic material, or other molding compound known to those skilled in the art. Mold inserts (not shown) may be used to create cavities  308  in the molded body by excluding molding material from portions of the mold. Those inserts are removed after molding, leaving cavities  308  within the molded body  306  in place of the inserts. Though the exemplary embodiment shows formation of a molded package array  302 , in other embodiments of the invention the molded bodies  306  may be formed individually. 
         [0052]      FIG. 3B  is a top view of a molded body  306  having an integrally-molded through-etched frame  304 . In the exemplary embodiment shown, the through-etched frame  304  is at least partially integrally molded with the molded body  306 . The large openings  308  in the molded body  306  may be used to form acoustic ports (not shown). Acoustic ports are discussed in detail further in the specification. 
         [0053]      FIG. 3C  is a bottom view of a singulated molded body  306  with a through-etched frame  304 . The small openings  310  in the molded body may be used to form vias (not shown). Vias may be solid or hollow. Hollow vias may be made using inserts (not shown) during the molding process to create openings in the molded body. For example, in embodiments of the invention having a frame with conductive posts (not shown), vias may be left hollow, with the posts (e.g., post  208 ) filling the space. This eliminates the step of filling in the vias, simplifying MEMS package manufacture. In other embodiments, vias may instead be filled in with conductive solder or epoxy, conductive paste, or other material (not shown), or by other methods known to those skilled in the art. In an exemplary embodiment of the invention such as the one shown in  FIGS. 3A-3C , vias (not shown) may be formed during molding, with multiple vias formed in multiple sites in a single step. In contrast, vias in non-integrally formed substrates are often formed in multiple steps by drilling through the body after the body is formed. 
         [0054]    B. Partially-Etched Design 
         [0055]    Partially-etched frames are frames where at least a portion of the frame is partially etched (e.g., half), but is not completely etched or stamped through. The partially-etched design includes a package substrate and method of fabrication. Each is described hereafter. 
         [0056]    1. Partially-Etched Frame 
         [0057]      FIG. 4A  shows an exemplary embodiment of an array  402  of partially-etched frames  404 . The partially-etched frames  404  shown are 50 um +/−25 um thick. In contrast with the through-etched frame described above, a partially-etched frame  404  is not etched or stamped completely through. Instead, the frame is only partially etched, ground, or ablated in order to create one or more die cavities (not shown) and circuitry patterns  406  on the frame  404 . For ease of reference, unless otherwise noted “partially-etched”, “ground”, and “ablated” are collectively referred to as “partially-etched.” The number, shape, and size of the etchings are exemplary only, and not limited to what is shown. In the embodiment shown the partially-etched frame  404  is part of an array  402 , but in other embodiments it may be individually manufactured. 
         [0058]    While the frames shown in the exemplary embodiment of  FIG. 4A  are metal, other embodiments may have frames that are at least partially non-metallic. In other embodiments, the frame may be at least partially conductive, and may have one or more conducting layers (not shown). The partially-etched frame  404  may optionally have one or more conducting layers (not shown). Connections among conducting layers may be through solid or hollow vias (not shown). Vias can be formed by any method known to those skilled in the art, including but not limited to use of conductive epoxy, metal insert, conducting fillers, or metal deposition. Vias are discussed in greater detail in the description of the embodiment of the invention shown in  FIGS. 3A-3C . 
         [0059]    2. Partially-Etched Frame Molded Package 
         [0060]      FIGS. 4B-4E  show an exemplary embodiment of a process used to create an array with the molded body  408  integral with a partially-etched frame  404 . The embodiments shown in  FIGS. 4B-4E  are exemplary only, and not limited to what is shown. For example, while shown as part of an array in  FIGS. 4B-4E , in other exemplary embodiments the molded body  408  and frame  404  may be manufactured individually. 
         [0061]    In the exemplary embodiment shown in  FIG. 4B , once a frame is formed, a molded body  408  is integrally molded with the frame. The frame shapes and patterns are exemplary only, and not limited to what is shown. Although the embodiment shown has a partially-etched frame  404 , other embodiments may have a molded body  408  at least partially integrally molded with a through-etched frame (not shown). The molding forming the molded body  408  may be one or more of a liquid crystal polymer, filled epoxy, filled nylon, poly ether ether ketones (PEEK), or other molding material known to those skilled in the art.  FIG. 4C  illustrates a bottom view of a partially-etched frame array  402  shown in  FIG. 4B . As shown in  FIG. 4C , inserts (not shown) may be used to form openings  410  in the molded body  408 . For example, the openings  410  may be shaped to house acoustic channels, vias, die cavities, and other MEMS package components. The size, shape, and location of the openings are exemplary only, and not limited to what is shown. 
         [0062]      FIG. 4D  illustrates a close-in view of an exemplary embodiment of a molded body  408  with an integrally-molded partially-etched leadframe  404  in accordance with the present invention, prior to removing the metal covering the openings  410  in the molded body  408 . As this embodiment shows, a partially-etched frame  404  allows for a thinner MEMS package (not shown), but leaves a portion of the frame covering the molded body openings  410 . Those portions of the frame may be etched, ground, or ablated to form the desired openings.  FIG. 4E  illustrates top view of an exemplary embodiment of a molded body array  402  with a partially-etched leadframe  404  in accordance with the present invention after metal covering the openings in the molded body  408  is removed. This step may be omitted in a molded body having a through-etched or stamped leadframe (not shown). 
         [0063]    II. Conductor on Substrate 
         [0064]    This section describes exemplary embodiments of the invention having a thin-core PCB over-mold and/or a plated molded body. Exemplary embodiments of each are discussed below. 
         [0065]    A. Thin-Core PCB Over-Mold 
         [0066]      FIGS. 5A and 5B  show exemplary embodiments of double-body MEMS packages  500 / 550  with the molded body  502  at least partially over-molded onto a printed circuit board  504 .  FIG. 5A  shows an exemplary embodiment of the present invention having a double body with a frame  506  and thin PCB over-mold  504 . In the exemplary embodiment shown in  FIG. 5A , sound enters the MEMS package  500  through a sound source acoustic port  508  in the top of the lid  510  and travels from the lid  510  into the molded body  502  until it reaches the MEMS die  512 . The location of the sound source acoustic port  508  is exemplary only, and not limited to what is shown. For example, the sound source acoustic port  508  may be relocated by repositioning inserts used to form the sound source acoustic port  508  during molding. The sound source acoustic port  508  connects to an acoustic channel  514 , which forms a sealed continuous path ending at a die site acoustic port  516 . The acoustic channel  514  propagates sound to a membrane (not shown) at MEMS package die  512 . The acoustic channel  514  may be formed by using one or more inserts (not shown) during the molding process, by drilling into the body the MEMS package  500 , or by other methods known to those skilled in the art. 
         [0067]    The printed circuit board  504  forms the bottom of the MEMS package  500 , further reducing package thickness. In embodiments where the sound source acoustic port  508  in on the bottom of the MEMS package (not shown), the printed circuit board  504  seals the acoustic channel  514  to form the completed sound transmission route from the sound source acoustic port  508  to the die site acoustic port  516 . The molded body  502  is over-molded onto the top of the printed circuit board  504 . Vias  518  in the molded body  502  connect to printed circuit board traces  520 . The vias  518  may be solid or hollow. The top of the molded body  502  then connects to a frame  506 . Any inserts (not shown) used during molding are removed, and the top of the molded body  502  is connected to the frame  506 . The frame  506  may be partially or through etched. The molded body  502  may connect to the frame  506  by welding to vias  518  in the molded body  502 , by solder or conductive paste, or other methods known to those skilled in the art. In embodiments with hollow vias  518 , conductive posts (not shown) in the frame  506  may insert into the vias  518  to connect electrically with the printed circuit board  504 . The top of the frame  506  attaches to a lid  510 . A description of the lid  510  and ways of attaching it to the frame is provided in the description of the embodiments shown in  FIGS. 10A and 10B . 
         [0068]    In the embodiment shown in  FIG. 5A , the frame  506  functions as a carrier for the MEMS die  512 . The MEMS die  512  is not limited to what is shown, and can be any die known to those skilled in the art. The MEMS die  512  may be placed in a die cavity  522 . The die  512  may attach to the frame  506  in either a flip chip or a bonding wire configuration. The die  512  in the embodiment shown in  FIG. 5A  attaches in a flip chip configuration. In other exemplary embodiments, the die  512  may attach in a bonding wire configuration. A description of both attachment configurations is provided in the description of the embodiments shown in  FIGS. 10A and 10B . 
         [0069]      FIG. 5B  shows an exemplary embodiment of a double-body MEMS package  550  with upper and lower printed circuit boards  504 / 552 . The upper printed circuit board  552  takes the place of a frame. Replacing the frame with a printed circuit board allows for an even thinner MEMS package, and greater interconnection flexibility. The molded body  502  may be molded either to the upper or lower printed circuit board  504 / 552 , but not both. In the exemplary embodiment shown in  FIG. 5B , the molded body  502  is over-molded to the lower printed circuit board  504 . In other embodiments, the molded body  502  may be molded to the upper printed circuit board  552 . In the embodiment shown, vias  518  in the molded body  502  connect to traces  520  on the lower printed circuit board  504 . The vias  518  may be solid or hollow. Solid vias  518  may be formed with a conductive solder or epoxy, conductive paste, or a polymer filled with conductive material (not shown). The top of the molded body  502  connects to the upper printed circuit board  552 . In the embodiment shown in  FIG. 5B , the upper printed circuit board  552  attaches to the molded body  502 . Any inserts (not shown) used to form the molded body  502  are removed prior to attaching the upper printed circuit board  552  to the molded body  502 . The molded body  502  may attach to the upper printed circuit board  552  using any of the methods and materials disclosed in the description of the attachment of the upper and lower molded bodies shown in  FIGS. 10A and 10B . 
         [0070]    In the embodiment shown in  FIG. 5B , an adhesive layer  554  attaches the upper printed circuit board  552  to a lid  510 . A description of the lid  510  and ways of attaching it are provided in the description of the embodiments shown in  FIGS. 10A and 10B . In the embodiment shown in  FIG. 5B , the upper printed circuit board  552  functions as a carrier for the MEMS die  512 . The MEMS die  512  may attach to the upper printed circuit board  552  in either a flip chip or a bonding wire configuration, and is not limited to what is shown. In the exemplary embodiment of  FIG. 5B  the die  512  attaches in a flip chip configuration. In other exemplary embodiments, the die  512  may attach in a bonding wire configuration. A description of both attachment configurations is provided in the description of the embodiment shown in  FIGS. 10A and 10B . 
         [0071]    B. Plated Molded Body 
         [0072]    In embodiments of the invention having a plated molded body, conductive plating may be used in place of a frame. The plated design includes a molded body and method of fabrication. Both are described below. 
         [0073]    1. Design 
         [0074]    In a plated MEMS Sensors Molded Package, the molded body is molded without a frame, and conductive traces are applied directly to the molded body. The traces may be plated onto the molded body, or applied using other methods known to those skilled in the art. This is called a plated design. In a plated design, the thickness of the leadframe (150 um for through-etched frames and 50 um +/−25 um for partially-etched frames) is replaced by metal plating as thin as 8 um or less. This allows even thinner MEMS packages (e.g., less than 1.3 mm). Examples of plating techniques are described in the article  Laser Supported Activation and Additive Metallization of Thermoplastics for  3 D - MIDS  by M. Huske et al., which is hereby incorporated by reference in its entirety. 
         [0075]    2. Fabrication 
         [0076]      FIG. 6A  shows an exemplary embodiment of a plated molded body  602 . Though shown as a single molded body  602 , in other embodiments the molded body  602  may be manufactured as part of an array (not shown). In the embodiment shown, rather than placing a frame into a mold and then adding molding compound, molding compound (not shown) is added to a mold without a frame. In this exemplary embodiment, plated conductors (also known as conductive traces  606 ) are added after molding the molded body  602 . The molded body  602  may be formed with grooves  604  and vias  608 , which may be used for conductor routing.  FIG. 6A  shows an example of a molded body  602  with grooves  604  prior to adding conductors (not shown). In the embodiment shown the grooves  604  define the location of conductor routings, while in other embodiments the grooves  604  may be omitted. The routings may conduct power or signals, or act as a grounding path. The grooves  604  may be formed during or after molding. The grooves  604  may be included in the mold tooling, or may be formed using other methods known to those skilled in the art. Though not shown, grooves may also be formed on other surfaces of the molded body, including the sides and the back. 
         [0077]      FIGS. 6B and 6C  show top and bottom views of the exemplary embodiment of the molded body  602  of  FIG. 6A , with conductive traces  606  plated on the grooves  604  and vias  608 . In other embodiments, the traces  606  may be plated instead of screen or stencil printed. In the embodiment shown, the conducting traces  606  and plated vias  608  may be formed by subtraction (etching away) or addition (plating or vacuum metallization). The conductive traces  606  may be conductive epoxy, metal, conductive paste, or other materials known to those skilled in the art. The conductive epoxy may be screen printed into the grooves  604  and vias  608 . Plating may also be accomplished using removable masking or seed layers (not shown) or other methods known to those skilled in the art. The conductive epoxy may be screen or stencil printed using techniques known to those skilled in art. Screen printing is described at page 483 and plating on page 714 of the book entitled “Microelectronics Packaging Handbook” edited by R. R. Tummala and E. J. Rymaszewski, Van Nostrand Reinhold, N.Y., 1989, which is hereby incorporated by reference in its entirety. The number, shape, and size of the traces shown in  FIGS. 6B and 6C  are exemplary only, and not limited to what is shown. 
         [0078]    III. Single-Body and Double-Body Embodiments of MEMS Packages with Integral Leadframe and/or Plated Molded Bodies 
         [0079]    The exemplary integral leadframe and plated molded bodies described above may be used to form embodiments of single-body and double-body MEMS packages according to the present invention. Exemplary embodiments of single and double-body MEMS packages are described below. Though not described or shown, other packages with more than two molded bodies may be used without departing from the scope of the invention. 
         [0080]    A. Single-Body Design-Leadframe Over-Mold 
         [0081]      FIGS. 7A-E  illustrate an exemplary embodiment of a single-body leadframe MEMS package  700  assembled in accordance with the present invention. Only the molded body, frame, MEMS die, and top and bottom lids are shown. Other items that would typically be part of an acoustic MEMS package are omitted for clarity. 
         [0082]    As shown in  FIG. 7A , assembly starts with the molded body  702 . In the exemplary embodiment shown, the molded body  702  has a leadframe  704  with conductive posts  706 , and a die cavity  708  for placing a MEMS die (not shown). The die cavity  708  has a die site acoustic port  710  for sound to enter the MEMS die  712 . The leadframe  702  may be through or partially etched. In the embodiment shown in  FIG. 7B , the MEMS die  712  is placed in the die cavity  708  (not shown). A lower lid  714  attaches to the bottom of molded body  702 , as shown in  FIG. 7C  and, as shown in  FIG. 7D , an upper lid  716  attaches to the top of the molded body  702 .  FIG. 7E  shows a cutaway view of the completed single-body molded MEMS package  700 . 
         [0083]      FIG. 8  shows an exemplary embodiment of the present invention having a singe-body MEMS package  800  with a sound source acoustic port  802  on the bottom of the package. In the single-body MEMS package  800  shown, the lower lid  804  and molded body  806  form the acoustic channel  808 , and interconnections are made using the frame (not shown). The frame may be through or partially etched. In other embodiments, leads may instead be plated on the molded body  806 . In the embodiment shown, sound enters the MEMS package  800  through a sound source acoustic port  802  in the bottom of the molded body  806 . The location of the sound source acoustic port  802  is exemplary only, and not limited to what is shown. After passing through the sound source acoustic port  802 , sound enters the acoustic channel  808 . The acoustic channel  808  forms a sealed continuous path ending at a die site acoustic port  812 . The acoustic channel  808  propagates sound to a membrane (not shown) at a die  810  in the MEMS package  800 . 
         [0084]    The lower lid  804  connects to the molded body  806  and seals the acoustic channel  808  to form the completed sound transmission route from the sound source acoustic port  802  to the die site acoustic port  812 . The size and location of the lower lid  804  are exemplary only, and not limited to what is shown. The lower lid  804  may be conductive. In other embodiments the lower lid  804  may be machined instead of molded, or formed through a combination of molding and machining, and is not limited to what is shown. Machining can be done mechanically, using a laser, or by other methods known to those skilled in the art. The lower lid  804  may be formed using one or more of a liquid crystal polymer, mold compound, filled epoxy, filled nylon, or poly ether ketone (PEEK). It may also be plated plastic, or stamped metal. In the exemplary embodiment shown, the lower lid  804  glues to the molded body  806 . In other embodiments, the lower lid  804  may connect to the molded body  806  using plastic joining techniques, by an adhesive layer (not shown), by an epoxy (not shown), be snapped in place using tabs with corresponding receivers (not shown), or by other methods known to those skilled in the art. 
         [0085]    In the exemplary embodiment of  FIG. 8 , the molded body  806  is at least partially integrally molded with a frame (not shown). The molded body  806  functions as a carrier for the MEMS die  810 . The MEMS die  810  is not limited to what is shown, and can be any die known to those skilled in the art. The MEMS die  810  may be placed in the die cavity  814  before molding the molded body to the frame (over-molding) or it may attach to the frame after molding the molded body  806  with the frame (pre-molding). The die  810  may attach to the frame (not shown) in either a flip chip or a bonding wire configuration. In embodiment shown in  FIG. 8  the MEMS die  810  attaches to a printed circuit board (not shown) in a bonding wire configuration using one or more bonding wires  816  connected to one or more conductive traces  818 . The connection to the MEMS die  810  is exemplary only, and not limited to what is shown. In other embodiments the bonding wires  816  may connect to one or more vias (not shown), plated through holes (not shown), or other connections known to those skilled in the art. 
         [0086]    The molded body  806  connects to an upper lid  820  which seals at least a portion of the die cavity  814 . The upper lid  820  may be formed by molding or machining, and is not limited to what is shown. It may be formed using one or more of a liquid crystal polymer, mold compound, filled epoxy, filled nylon, or poly ether ketone (PEEK). The upper lid  820  may also be plated plastic, or stamped metal. In certain embodiments, the upper lid  820  may be conductive and form a Faraday Cage by connecting to a grounding connection, such as a grounding ring  822 . In the exemplary embodiment shown, the upper lid  820  is comprised of molded liquid crystal polymer (LCP), and glues to the MEMS package  800 . In other embodiments, an adhesive layer (not shown) may connect the upper lid  820  to the molded body  806 . In still other embodiments, attachment can be by any means known to those skilled in the art. 
         [0087]    B. Double-Body Design-Leadframe Over-mold 
         [0088]      FIGS. 9A-10B  illustrate exemplary embodiments of double-body MEMS packages. A double-body MEMS package has two molded bodies instead of one. One or both of the molded bodies may have an integral leadframe, or a plated molded package. While the double-body MEMS packages have many similarities to the single-body MEMS packages, the double-body embodiments may have a conductive bottom lid for electrically connecting the upper and lower molded bodies. 
         [0089]      FIG. 9A  shows a top view of an exemplary embodiment of a bottom lid  902  with portions of the exposed frame  904  etched, molded, and patterned by an organic layer (not shown). An organic layer is a non-conductive epoxy or solder mask compound. Organic layers may be molded and/or patterned using an epoxy or solder mask screen printing. In the exemplary embodiment shown, the bottom lid conducting layers (not shown) are manufactured by patterning the frame  904 . 
         [0090]    The exposed portions of the conducting layers  904  are called pads  906 . Pads  906  connecting to the molded body (not shown) are formed by stamping, etching, or ablating a pattern onto the frame  904 . In the embodiment shown, the pads  906  are copper, but are not limited to what is shown and may be any conductive material. In the exemplary embodiment shown in  FIG. 9A , the pads  906  on the top of the bottom lid  902  electrically connect to the molded body. In the embodiment shown, the pads  906  are soldered to connections (not shown) on the molded body. The solder may be conductive. In other embodiments, the pads  906  may connect to the molded body using tape, conductive paste, or other materials known to those skilled in the art. The pad layout is exemplary only, and not limited to what is shown. Other pad layouts may be created simply by changing the plating pattern. Vias (not shown) in the upper and lower molded bodies (not shown) can be used with multitude pad layout patterns, allowing for much greater design flexibility. 
         [0091]      FIG. 9B  shows a bottom view of an exemplary pad layout connecting the bottom lid  902  to a printed circuit board (not shown). The top of the bottom lid  902  forms the bottom surface of the acoustic channel (not shown) and connects to a molded body (not shown) by a lower adhesive layer (not shown). In other exemplary embodiments, the bottom lid  902  may connect to a molded body (not shown) using an epoxy, solder, tape, or other bonding material know to those skilled in the art. 
         [0092]    In the exemplary embodiment shown in  FIG. 9B , pads  906  on the bottom of the bottom lid  902  electrically connect to a printed circuit board (not shown). The pads  906  may be soldered to printed circuit board connections (not shown). The solder may be conductive. In other embodiments, the pads  906  may connect to the printed circuit board using tape, conductive paste, or other materials known to those skilled in the art. A conductive ring  908  around the perimeter of the bottom lid  902  forms a ground. The shape of the ground is exemplary only, and not limited to the conductive ring  908  shown. The number and arrangement of the pads  906  is also exemplary only, and not limited to what is shown. The pads  906  may be in a land grid array (LGA), or other pattern as required. 
         [0093]      FIGS. 10A and 10B  show exemplary embodiments of double-body acoustic MEMS packages  1000 / 1050  with upper and lower molded bodies  1002 / 1004 . The upper and lower molded bodies  1002 / 1004  may have one or more of a through-etched, partially-etched, or plated configuration. In the embodiment shown in  FIGS. 10A and 10B , the upper molded body  1002  is at least partially integrally molded with a frame (not shown). The frame may be through or partially etched. In a double-body MEMS package, interconnections and the acoustic channel are formed by the upper and lower bodies  1002 / 1004 .  FIG. 10A  shows an exemplary embodiment of a double-body MEMS package  1000  with a top acoustic port. In this exemplary embodiment, sound enters the MEMS package  1000  through a sound source acoustic port  1006  in the top of the lid  1008  and travels through the upper and lower molded bodies  1002 / 1004  until it reaches the MEMS die  1010 .  FIG. 10B  shows an exemplary embodiment of a double-body MEMS package  1050  with a bottom port. In this exemplary embodiment, sound enters the MEMS package  1050  through a sound source acoustic port  1006  in the bottom of the lower molded body  1004  and travels through the lower and upper molded bodies  1004 / 1002  until it reaches the MEMS die  1010 . The location of the sound source acoustic port  1006  is exemplary only, and not limited to what is shown. The location of the sound source acoustic port  1006  may be located elsewhere by repositioning inserts used to form the sound source acoustic port  1006  during molding of the upper and lower molded bodies  1002 / 1004 . In the exemplary embodiments shown in  FIGS. 10A and 10B , the sound source acoustic port  1006  connects to an acoustic channel  1012 , which forms a sealed continuous path ending at a die site acoustic port  1014 . After passing through the sound source acoustic port  1006 , sound enters the acoustic channel  1012 . The acoustic channel  1012  propagates sound to a membrane (not shown) at the die  1010 . The acoustic channel  1012  may be formed by using one or more inserts (not shown) during the molding process, by drilling into the MEMS package, or by other methods known to those skilled in the art. 
         [0094]    The lower molded body  1004  connects to the upper molded body  1002  and seals the acoustic channel  1012  to form the completed sound transmission route from the sound source acoustic port  1006  to the die site acoustic port  1014 . In other embodiments, the acoustic channel  1012  may be sealed using solder, adhesive, plastic joining techniques, snapped in place using tabs with corresponding receivers (not shown), or by other methods known to those skilled in the art. In other embodiments the lower body may be machined instead of molded, or formed through a combination of molding and machining. Machining can be done mechanically, using a laser, or by other methods known to those skilled in the art. In still other embodiments, the lower molded body  1004  may be at least partially integrally molded with a frame (not shown), or printed circuit board (not shown). In the embodiment shown a lower adhesive layer  1016  connects the upper and lower bodies  1002 / 1004 . In still further exemplary embodiments, the upper and lower molded bodies  1002 / 1004  may snap or glue together. In still further embodiments, solder may be used to connect the upper and lower molded bodies  1002 / 1004 . The solder may be conductive. Conductive traces  1018  electrically connect the upper and lower molded bodies  1002 / 1004 . In other embodiments conductive vias (not shown) or conductive posts (not shown) may electrically connect the upper and lower molded bodies  1002 / 1004 . 
         [0095]    In the exemplary embodiments shown in  FIGS. 10A and 10B , the upper molded body  1002  functions as a carrier for the MEMS die  1010 . The MEMS die  1010  is not limited to what is shown, and can be any die known to those skilled in the art. The MEMS die  1010  may be placed in the die cavity  1020  before molding the molded body to the frame (over-molding) or it may attach to the frame after molding the upper or lower body  1002 / 1004  with the frame (pre-molding). In an over-molded configuration, the die  1010  attaches to the frame (not shown) prior to molding the upper or lower molded body  1002 / 1004  to the frame. In a pre-mold configuration, the upper or lower molded body  1002 / 1004  is molded with the frame, and then the die attaches to the frame via exposed pads (not shown). The die may attach to the frame (not shown) in either a flip chip or a bonding wire configuration. In embodiments shown in  FIGS. 10A and 10B  the die  1010  attaches in a flip chip configuration. In a flip chip configuration, the die  1010  is inverted, so that the top of the die  1010  attaches to surface mount pads (not shown) on the conductive traces  1018 . Attachment may be by gold bumping, soldering, conductive adhesive or epoxy, or other methods known to those skilled in the art. Attaching the die  1010  in a flip chip configuration eliminates the need to leave room in the lid for the bonding wires required in a bonding wire configuration, allowing for a substantial reduction in overall package height (thickness). 
         [0096]    An upper adhesive layer  1022  connects the upper molded body  1002  to the lid  1008  and seals the MEMS package  1000 / 1050 . The lid  1008  may be formed by molding or machining, and is not limited to what is shown. It may be formed using one or more of a liquid crystal polymer, mold compound, filled epoxy, filled nylon, or poly ether ketone (PEEK). The lid  1008  may also be plated plastic, or stamped metal. In certain embodiments, the lid  1008  may be conductive and form a Faraday Cage by connecting to a grounding connection, such as a grounding ring  1024 . In the exemplary embodiment shown, the lid  1008  is comprised of molded liquid crystal polymer (LCP), which is glued to the MEMS package  1000 / 1050  and allowed to cure. Use of an adhesive layer is exemplary only, and not limited to what is shown. In other embodiments attachment can be by other ways known to those skilled in the art. 
         [0097]    Although several embodiments of the present invention and its advantages have been described in detail, it will be apparent to those skilled in the art that various modifications and variations can be made in the apparatus and method of the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.