Patent Application
20090152653
The present invention relates generally to electronics packaging and more particularly to electronic packaging for micro-electrical mechanical system (MEMS) devices.
Electro-Mechanical Systems (MEMS) is the integration of mechanical elements, sensors, actuators, and electronics on a common silicon substrate through microfabrication technology. While the electronics are fabricated using integrated circuit (IC) process sequences (e.g., CMOS, Bipolar, or BICMOS processes), the micromechanical components are fabricated using compatible “micromachining” processes that selectively etch away parts of the silicon wafer or add new structural layers to form the mechanical and electro-mechanical devices. MEMS brings together silicon-based microelectronics with micromachining technology, making possible the realization of complete systems-on-a-chip devices. MEMS is an enabling technology allowing the development of smart products, augmenting the computational ability of microelectronics with the perception and control capabilities of microsensors and microactuators and expanding the space of possible designs and applications.
While microelectronic ICs work to control functional processing steps in the system, MEMS augments this decision-making capability to allow microsystems to sense and control the environment. Thus, the primary applications of MEMS technology include sensors that gather information from the environment through measuring such parameters as mechanical, thermal, bio-logical, chemical, optical, and magnetic phenomena. The MEMS electronics then process the information derived from the sensors and, through some decision-making capability, direct the actuators to respond by controlling the environment for some desired outcome or purpose. Because MEMS devices are manufactured using batch fabrication techniques similar to those used for integrated circuits, unprecedented levels of functionality, reliability, and sophistication can be achieved using small silicon MEMS chips at a relatively low cost.
In MEMS applications, such as automotive sensors, such as those having accelerometer or gyroscopic applications, it is often required for the sensor to be used in multiple applications with different axis of sensing. Normally, silicon-based sensors (MEMs) are designed to be sensitive in one axis with little or no sensitivity in other axis. In order for the sensor to be used in other axis, the surrounding MEMS device package must be designed to accommodate the specified orientation with variations in either an X, Y, or Z axis.
Prior art
An embodiment of the present invention is directed to a surface mount multi-axis cavity package for micro-electrical mechanical systems (MEMS) devices that includes a substantially cubical housing having at least one internal cavity. A first group of solder pads are positioned on at least one side of the housing and a second group of solder pads are positioned on a bottom of the housing. A MEMS sensor is mounted within the internal cavity and a lead frame is positioned within a wall of the cubical housing for interconnecting the first group of solder pad connections and the second group of solder pad connections. The multi-axis package is very advantageous as it allows a MEMS device to be mounted within the package on its X or Y axis such that the package can then be connected on a printed circuit board for increasing the overall versatility of the MEMS device
These and other features, advantages, and objects of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specifications, claims, and appended drawings.
The present invention will now be described, by way of example, with reference to the accompanying drawings, in which:
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.
Before describing in detail embodiments that are in accordance with the present invention, it should be observed that the embodiments reside primarily in combinations of method steps and apparatus components related to a surface mount multi-axis cavity package for with use with a microelectrical mechanical system (MEMS) device. Accordingly, the apparatus components and method steps have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.
In this document, relational terms such as first and second, top and bottom, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms “comprises,” “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by “comprises . . . a” does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.
It will be appreciated that embodiments of the invention described herein may be comprised of one or more conventional processors and unique stored program instructions that control the one or more processors to implement, in conjunction with certain non-processor circuits, some, most, or all of the functions of microelectrical mechanical system (MEMS) packaging device described herein. The non-processor circuits may include, but are not limited to, a radio receiver, a radio transmitter, signal drivers, clock circuits, power source circuits, and user input devices. As such, these functions may be interpreted as steps of a method to construct a microelectrical mechanical system (MEMS) packaging device. Alternatively, some or all functions could be implemented by a state machine that has no stored program instructions, or in one or more application specific integrated circuits (ASICs), in which each function or some combinations of certain of the functions are implemented as custom logic. Of course, a combination of the two approaches could be used. Thus, methods and means for these functions have been described herein. Further, it is expected that one of ordinary skill, notwithstanding possibly significant effort and many design choices motivated by, for example, available time, current technology, and economic considerations, when guided by the concepts and principles disclosed herein will be readily capable of generating such software instructions and programs and ICs with minimal experimentation.
Finally,
Thus, the present invention is directed to a surface mount multi-axis cavity package for MEMS sensor that can be mounted in multiple orientations. The multi-axis packages utilizes a leadfame that is insert molded in high temperature thermoplastic with exposed surfaces in a side and bottom of the package for solder mounting to a PC board. Inside the package cavity, a sensor and mating sensor are mounted to ceramic and/or organic circuit board via a flip chip technique or wirebonding. The PC board is connected to the package via wire bonding or other compliant pin outs. The multi-axis package can be used with a single integrated sensor, such as bare die or pre-packaged, as well as a two chip sensor, such as a sensor and application specific integrated circuit (ASIC) combination. After the sensor is packaged within the cube, it can be covered by a top or lid such that the multi-axis package can be mounted in any needed application.
In the foregoing specification, specific embodiments of the present invention have been described. However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope of the present invention as set forth in the claims below. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of present invention. The benefits, advantages, solutions to problems, and any element(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential features or elements of any or all the claims. The invention is defined solely by the appended claims including any amendments made during the pendency of this application and all equivalents of those claims as issued.
It will be understood by those who practice the invention and those skilled in the art, that various modifications and improvements may be made to the invention without departing from the spirit of the disclosed concept. The scope of protection afforded is to be determined by the claims and by the breadth of interpretation allowed by law.
