Abstract:
A modular package may be utilized to mount an RF system-on-chip in one of plural configurations, such that the same modular package may be utilized to enable plural device formats, while reducing the amount of RF testing needed to change device formats. In one configuration, a surface mount device is mounted onto a first surface of a board, and the board is directly surface mounted onto a base board. Here, the base board includes a hole for accommodating the surface mount device, providing a thin device format. In a second configuration, a spacer is mounted onto the first surface of the board, such that a gap is provided between the board and the base board for accommodating the surface mount device, providing a relatively thicker device, but providing additional surface area where the hole otherwise would be, reducing the device size.

Description:
BACKGROUND 
     1. Field 
     Aspects of the present disclosure relate generally to electronic circuit packaging, and more particularly, to surface mount packaging for an RF system-on-chip. 
     2. Background 
     Currently, the use of surface mount technology for mounting packaged semiconductor devices onto printed circuits boards is well known. Surface mount packaging can provide for a thin profile end device, where the packaged semiconductor device may lay substantially flat on a thin board. In addition, consolidation and integration of multiple modules or devices into a single module such as a system-on-chip has been widely employed. 
     However, with the proliferation of mobile telecommunications devices, the desire to reduce the thickness and size of a system board has lead to significant developmental effort in the area of device packaging. Further, when a system-on-chip is an RF system such as one to be utilized in a mobile telecommunications device, extensive testing and analysis is frequently required to certify the end device. 
     Because of the unending desire for small, but unique device designs, there continues to exist a need in the art for improved surface mount packages, especially those that may provide for reduced testing costs and increased versatility. 
     SUMMARY 
     In various representative aspects, the present disclosure provides a modular package for mounting a semiconductor system-on-a-chip into a device like a mobile phone. A modular package in accordance with an aspect of the disclosure may be mounted in one of two available configurations. In a first configuration, the module may be directly mounted onto a base board, wherein the base board may include a hole into which any surface mount packages mounted on a first surface of the modular package may be deposited. In a second configuration, a spacer may be mounted onto the modular package. With the spacer, the modular package may be surface mounted onto a base board that does not necessarily include a hole. 
     In one aspect, the disclosure provides that the configurations of the modular package with and without the spacer may be substantially identical in terms of functionality. In this way, the module is capable of being pre-tested and certified in each of the configurations, such that the decision to change from one configuration to another may not require extensive additional testing. 
     Another aspect of the disclosure provides that the module directly mounted to the base board without utilizing the spacer maintains a very thin profile, enabling a very thin end device. 
     Another aspect of the disclosure provides that the module including the spacer and mounted to the base board may be slightly thicker than the first configuration, but because a hole is not required in the base board, it may provide more surface area on an opposite side of the base board for the mounting of additional devices, enabling a smaller area device that may not be as thin as the first configuration. Here, the base board may function as RF shielding over the electronic components of the module. 
     In one example, a modular package may include a board having a first surface and a second surface opposing the first surface. The first surface may include a plurality of connection pads located at a periphery of the board and configured to enable surface mounting of the board. The board and the connection pads may be configured to enable direct surface mounting of the modular package onto a base board, as well as to enable surface mounting of the modular package onto the base board utilizing a spacer between the connection pads and the base board. 
     In another example, an apparatus may include means for directly mounting an integrated system-on-chip, having at least one surface mount device on a first surface of a board, onto a surface of a base board, such that the at least one surface mount device is in a hole in the base board. The apparatus may further include means for providing a gap between the surface of the base board and the at least one device such that the at least one surface mount device is in the gap when the integrated system-on-chip is mounted onto the surface of the base board without the hole in the base board. 
     In another example, a method of mounting a modular package onto a base board may include coupling a spacer to a first surface of the modular package, and coupling the spacer to a first surface of the base board, such that the spacer forms a gap between the first surface of the modular package and the first surface of the base board for accommodating at least one surface mount device mounted on the first surface of the modular package. Here, the modular package may be further configured for directly mounting onto a second base board having a hole for accommodating the at least one surface mount device mounted on the first surface of the modular package, without utilizing the spacer. 
     These and other aspects are more fully comprehended upon review of this disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of surfaces of a modular surface mount package for a system on a chip in accordance with an aspect of the disclosure. 
         FIG. 2  is a perspective view of a spacer and a modular surface mount package for a system on a chip utilizing the spacer in accordance with an aspect of the disclosure. 
         FIG. 3  is a cross-sectional view of a modular surface mount package for a system on a chip mounted onto a base board without utilizing a spacer in accordance with an aspect of the disclosure. 
         FIG. 4  is a cross-sectional view of a modular surface mount package for a system on a chip mounted onto a base board with a spacer in accordance with an aspect of the disclosure. 
         FIG. 5  is a perspective view of a modular surface mount package utilizing a spacer with two segments in accordance with an aspect of the disclosure. 
         FIG. 6  is a perspective view of a modular surface mount package utilizing a spacer with three segments in accordance with an aspect of the disclosure. 
         FIG. 7  is a flow chart illustrating a process of mounting a modular surface mount package in accordance with an aspect of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description, only certain examples of the present invention are shown and described, by way of illustration. As those skilled in the art would recognize, the invention may be embodied in many different forms and should not be construed as being limited to the examples set forth herein, but rather, to broadly include the features set forth throughout the instant specification. In the context of the present specification, when an element is referred to as being “on” another element, it can be directly on the other element or be indirectly on the other element with one or more intervening elements interposed therebetween. Also, in the context of the present specification, when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or be indirectly connected or coupled to the other element with one or more intervening elements interposed therebetween. Like reference numerals designate like elements throughout the specification. 
       FIG. 1  is a perspective diagram of a modular package for mounting a system-on-a-chip into a larger module. In the illustrated example, the module includes one or more surface mount devices  106  mounted to a first surface  102  of a first board  100 , with one or more surface mount devices  108  optionally mounted on a second surface  104  of the first board  100 . The surface mount devices  108  may be accompanied by, or replaced with, through-hole mounted devices, or may be eliminated in some aspects of the disclosure. 
     The first board  100  may be a printed circuit board (PCB) or any other suitable board for mechanically supporting various devices such as surface mount packages to one or more of its surfaces, and may include wires, routing, traces, vias, ground planes, and/or any other suitable mechanisms for electrically coupling various devices mounted to the first board  100 . Further, the first board  100  may include any suitable number of layers, from zero or more, between the first surface  102  and the second surface  104 . 
     The first surface  102  of the first board  100  may include surface mount connection pads  110  such as at least one ball grid array (BGA) at its periphery. For example, the connection pads  110  may be located at or near one or more edges of the first board  100 . These connection pads  110  are generally electrically coupled through wires or traces to various pins or connection pads on the various surface mount devices  106  and  108  mounted to the respective first  102  and second  104  surfaces of the first board  100 , for interfacing one or more of those devices with external devices or modules. 
     When mounting the modular package without utilizing a spacer, as illustrated in  FIG. 1 , an RF shield  112  (see  FIG. 3 ) may be utilized to cover the various surface mount devices  108  mounted on the second surface  104  of the first board  100  to prevent EMI (electromagnetic interference) and EMC (electromagnetic compatibility). 
       FIG. 2  is a perspective diagram of one example of a spacer  200  and how it may be mounted onto the modular package. The spacer  200  in this example includes a first surface  202  and a second surface  204  opposed to the first surface  202 , with each of the first  202  and second  204  surfaces including connection pads  206 ,  208  on the respective surfaces  202 ,  204 . In the illustrated example, the spacer  200  has a form similar to that of a picture frame, with a hole  210  in a central region and having the connection pads located around a periphery of their respective surfaces. The spacer  200  may be a PCB or any suitable board configured to enable structural support of the first board  100  and electrical coupling between the first board  100  and a base board onto which the first board  100  can be mounted. Further, the spacer  200  may include wires, routing, traces, vias, ground planes, and/or any other suitable mechanisms for electrically coupling various elements such as the connection pads  206  and  208 . 
     When the modular package utilizes the spacer  200 , an RF shield is not required to cover the surface mount devices  106  on the first surface  106  of the first board  100 , because the base board that the module is to be mounted onto may function as the RF shield. 
     Referring now to  FIG. 3 , in one configuration, the modular package may be directly mounted onto a base board  300  without the use of the spacer  200 . Here, the base board  300  includes a hole  304  such that the surface mount device  106  mounted to the first surface  102  of the first board  100  settles into the hole  304 . That is, the base board  300  includes connection pads  306  such as a BGA that are adapted to be electrically coupled, e.g., soldered to the connection pads  110  on the first board  100 , and wires or traces to the external devices or modules electrically coupled to the connection pads  306  by way of the base board  300 . Because the surface mount device  106 , which is deposited into the hole  304 , may be an RF device, or may be sensitive to RF interference, in an aspect of the disclosure an RF shield  302  may be placed over the surface mount device  106  so that it may provide RF shielding. 
     This configuration illustrated in  FIG. 3  provides for a thin profile, wherein the total thickness of the entire module (e.g., including the modular package, the base board  300 , and any articles mounted thereon) can be as thin as the combined thickness of the base board  300 , the first board  100 , and any devices mounted on the second surface  104  of the first board  100  such as surface mount devices  108  or any RF shielding  112  that may be utilized to shield the one or more surface mount devices  108 . That is, because the one or more surface mount devices  106  mounted on the first surface  102  are settled into the hole  304  in the base board  300 , the overall thickness can be reduced. 
     Referring now to  FIG. 4 , in another configuration, the spacer  200  may be added to the modular package. So that any surface mount devices  106  may fit between the first board  100  and a base board  308 , the spacer  200  may have the same or greater thickness than that of the surface mount devices  106  on the first surface  102  of the first board  100 . Unlike the configuration illustrated in  FIG. 3 , in this configuration, with the spacer  200  in place, the base board  308  onto which the modular package is mounted does not require a hole  304 . Thus, the modular package, including the spacer  200 , is mounted onto a surface of the base board  308 , with the connection pads  208  on the second surface  204  of the spacer  200  are coupled, e.g., soldered to the connection pads  310  on the base board  308 . In this second configuration illustrated in  FIG. 4 , because there is no hole  304  in the base board  308 , additional devices can be mounted on a second surface  312 , opposite to the mounted modular package. 
     In the configuration illustrated in  FIG. 4 , although the thickness may be greater than that of the configuration illustrated in  FIG. 3  approximately by the thickness of the spacer  200 , a more spatially dense arrangement of devices may be achieved by mounting additional devices to the second surface  312  of the base board  308  where the hole  304  might otherwise be. Thus, utilizing the configuration illustrated in  FIG. 4 , a reduced size of a device is enabled. Further, the base board  308  itself can act as the RF shield to shield the surface mount devices  106  mounted on the first surface  102  of the first board  100 , potentially eliminating the need for a separate RF shield  302  (see  FIG. 3 ). 
     In the configuration that includes the spacer, the base board may include plating (e.g., a copper ground plane) over the area where the hole was, in order to function as RF shielding over the area of the components of the module so that the RF shield on the module is not required. That is, in the configuration utilizing the spacer  200 , the RF shield  302  is not required on the first surface  102  of the board  100  to cover the surface mount devices  106  when the base board  308  includes a suitable copper ground layer over the component area. 
     In some aspects of the disclosure, the spacer can take other forms different from the picture frame form illustrated in  FIG. 2 . In general, any suitable form that would provide structural support for mounting the first board  100  onto the base board  308  in such a way as to provide a gap with adequate space for the one or more surface mount devices  106  between the first board  100  and the base board  308  without necessarily requiring a hole  304  through the base board  308  may be utilized. For example, as illustrated in  FIG. 5 , the spacer  500  may include a first segment  502  and a second segment  504 . Here, each of the first segment  502  and the second segment  504  are configured to be positioned adjacent to opposite edges  506  and  508  of a surface mount device  106  mounted on the first surface  102  of the first board  100 . In another example, as illustrated in  FIG. 6 , the spacer  600  may include a first segment  602 , a second segment  604 , and a third segment  606 , each configured to be positioned adjacent to respective edges  608 ,  610 , and  612  of a surface mount device  106  mounted on the first surface  102  of the first board  100 . Here, the first edge  608  is adjacent to the second edge  610 , such that the first segment  602  and the second segment  604  are joined at a first corner  614 . Similarly, the second edge  610  is adjacent to the third edge  612 , such that the second segment  604  and the third segment  606  are joined at a second corner  616 . In this way, the first segment  602 , the second segment  604 , and the third segment  606  generally form a U-shape to surround three sides of the surface mount device  106 . In other examples, such spacers may take a form such as, but not limited to, a V-shape or an L-shape, including two segments of a square; a circular shape or one or more portions of a circular shape; or any other suitable shape. Further, the gap between the first board  100  and the base board  308  can take any suitable shape that may accommodate the one or more surface mount devices  106 , and may be a closed gap (e.g., wherein segments of the spacer surround all sides of the one or more surface mount devices  106 ), or an open gap (e.g., wherein one or more sides of the one or more surface mount devices  106  is not adjacent to a segment of the spacer). 
       FIG. 7  is a flow chart  700  illustrating a process of mounting a modular package onto a base board in accordance with some aspects of the disclosure. In some aspects, the process may be realized by any number of hardware or software components configured to perform the specified functions and achieve the various results. For example, the various coupling, mounting, and providing processes may be employed, e.g., by an integrated automatic manufacturing system utilizing machinery, flow soldering, robotics, etc.; by an individual utilizing a soldering iron and conventional tools; etc. Further, the testing of the modular package may be employed, e.g., by any suitable testing system including, e.g., a processing system, a communication test set, a spectrum analyzer, or other suitable testing systems as known to those skilled in the art, each of which may carry out a variety of functions. In addition, aspects of the disclosure may be practiced in conjunction with any number of manufacturing and testing processes, and the system described is merely one exemplary application. Further, any number of conventional techniques may be employed for assembly, testing, and the like. 
     In block  702 , the process provides a modular package and a spacer. Here, the modular package may be similar to that illustrated in  FIG. 1 , including, e.g., at least one surface mount device mounted onto a printed circuit board. In block  704 , the modular package may be tested. Here, any suitable testing system may be utilized to test for one or more operational parameters, such as but not limited to RF emission power, interference susceptibility, etc. In block  706 , to utilize one configuration, the process couples a spacer to a first surface of the modular package, and in block  708 , the process couples the spacer to the first surface of a base board. In this fashion, the modular package can be mounted onto the base board in such a way that a gap exists between the printed circuit board of the modular package, and the base board, to accommodate the at least one surface mount device mounted onto the printed circuit board. Further, one or more devices may be mounted onto an opposing surface of the base board, opposite to the gap, to enable a smaller size of the device as a whole. 
     In order to utilize a second configuration, in block  710 , the process provides a hole in the base board, and in block  712 , the process directly mounts the modular package to the first surface of the base board such that the at least one surface mount device mounted onto the printed circuit board is accommodated by the hole in the base board. In this fashion, the modular package can be mounted onto the base board in such a way that the overall thickness of the device can be reduced by way of the at least one surface mount device sinking into the hole as the modular package is mounted onto the base board. 
     Those skilled in the art will comprehend that the steps of the process described in blocks  702  and  704  may be performed on a plurality of modular packages, such that each of the plurality of packages is tested and its functional characteristics are known. Thereafter, some of the modular packages may be mounted in one configuration as described in blocks  706  and  708 , and other ones of the modular packages may be mounted in a different configuration as described in blocks  710  and  712 . In this way, the number of process steps required to manufacture end products having different configurations is reduced. Further, the steps described in blocks  702  and  704  may be done at a manufacturer, after which the resultant modular packages may be utilized by different entities which may perform either one of the process steps described in blocks  706  and  708 ; or those described in blocks  710  and  712 . In either case, the amount of testing required to result in a plurality of configurations can be substantially reduced. 
     In the foregoing specification, certain representative aspects of the invention have been described with reference to specific examples. Various modifications and changes may be made, however, without departing from the scope of the present invention as set forth throughout the specification. The specification and figures are illustrative, rather than restrictive, and modifications within the scope of the present disclosure are intended to be included within the scope of the invention. Accordingly, the scope of the invention should be determined by the claims and their legal equivalents rather than by merely the examples described. 
     For example, the steps recited in any method or process claims may be executed in any order and are not limited to the specific order presented in the claims. Additionally, the components and/or elements recited in any apparatus claims may be assembled or otherwise operationally configured in a variety of permutations and are accordingly not limited to the specific configuration recited in the claims. 
     Furthermore, certain benefits, other advantages, and solutions to problems have been described above with regard to particular examples; however, any benefit, advantage, solution to a problem, or any element that may cause any particular benefit, advantage, or solution to occur or to become more pronounced is not to be construed as a critical, required, or essential feature or component of any or all the claims. 
     As used herein, the terms “comprise,” “comprises,” “comprising,” “having,” “including,” “includes” or any variation thereof, are intended to reference a non-exclusive inclusion, such that a process, method, article, composition or apparatus that comprises a list of elements does not include only those elements recited, but may also include other elements not expressly listed or inherent to such process, method, article, composition, or apparatus. Other combinations and/or modifications of the above-described structures, arrangements, applications, proportions, elements, materials, or components used in the practice of the present invention, in addition to those not specifically recited, may be varied or otherwise particularly adapted to specific environments, manufacturing specifications, design parameters, or other operating requirements without departing from the general principles of the same. 
     Moreover, reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more.” Unless specifically stated otherwise, the term “some” refers to one or more. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. §112, sixth paragraph, unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for.”