Aspects of the present disclosure relate generally to a semiconductor package having an electromagnetic interference (EMI) shield and, more particularly, to a semiconductor package having a tapered EMI shield.
Semiconductor devices are commonly used in electronic products such as cellular phones, video cameras, portable music players, printers, computers, etc. A trend for semiconductor devices is miniaturization, lightness and multifunction. Semiconductor devices emit electromagnetic radiation in the range from approximately 50 MHz to 3 GHz depending on the speed of the microprocessor. As the speed of microprocessor continues to increase, and as semiconductor devices continue to get smaller, there is a gradual increase in electromagnetic radiation emission. Electromagnetic radiation acts as electromagnetic interference (EMI) or radio frequency interference (RFI) that hinders the operation of other electronic equipment that may result in equipment failures. That is, EMI or RFI acts as a disturbance that may affect an electrical circuit by electromagnetic induction, electrostatic coupling, or conduction. The disturbance may degrade the performance of the circuit or even stop it from functioning. Current semiconductor devices include EMI shields that are formed by spraying, sputtering, or plating that have resulted in non-uniform top and side surface thicknesses. Accordingly, there is a need for a semiconductor device and process for forming an EMI shield on the semiconductor device having similar top and side surface thicknesses using existing process technology.
The following presents a simplified summary of one or more aspects or embodiments to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.
A method of manufacturing a semiconductor package according to one aspect is described. The method comprises mounting and bonding a die on a surface of a substrate, forming a mold over the die and on the substrate, cutting the mold having a top surface and a plurality of side surfaces, wherein the side surfaces are tapered cut to allow uniform thickness during spraying or sputtering of an EMI shielding film, and spraying or sputtering the mold with the EMI shielding film. The bonding of the die may be done by surface mounted components (SMC) using a thermally and/or electrically conductive adhesive. The conductive adhesive may include solder and/or epoxy. The taper cutting may be done with a diamond saw.
A semiconductor package according to one aspect is described. The semiconductor package comprises a substrate, a die mounted on the substrate, and a mold formed over the die and on the substrate, the mold having a top surface and a plurality of tapered side surfaces, wherein the tapered side surfaces provide uniform thickness of an electromagnetic interference (EMI) shielding film. The tapered side surfaces provide uniform thickness of the EMI shielding film during spraying or sputtering of the EMI shielding film. The mold may comprise synthetic resin. The EMI shielding film may comprise at least one or more layers of a metallic element comprising at least one of Ni, Cu, Ag, or Fe. The EMI film thickness is approximately 4000 Å to 8000 A. The tapered side surfaces have an incident angle of approximately 20% to 65% to maintain uniform thickness. In another aspect, each of the tapered side surfaces may be tapered cut to a plurality of cut surfaces having different incident angles.
These and other aspects of the invention will become more fully understood upon a review of the detailed description, which follows. Other aspects of the invention will become apparent to those of ordinary skill in the art, upon reviewing the following description of specific, exemplary aspects of the invention in conjunction with the accompanying figures.
The detailed description set forth below, in connection with the appended drawings, is intended as a description of exemplary aspects and is not intended to represent the only aspects in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form in order to avoid obscuring such concepts.
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When sputtering, a plasma gas is filled in the sputtering chamber at a certain pressure, and then power is supplied to the sputtering chamber to allow a target metal to be deposited on the exposed tapered side and top surfaces of the molds 306a and 306b. The sputtering step as illustrated in
Within the present disclosure, the word “exemplary” is used to mean “serving as an example, instance, or illustration.” Any implementation or aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects of the disclosure. Likewise, the term “aspects” does not require that all aspects of the disclosure include the discussed feature, advantage or mode of operation. The term “coupled” is used herein to refer to the direct or indirect coupling between two objects. For example, if object A physically touches object B, and object B touches object C, then objects A and C may still be considered coupled to one another—even if they do not directly physically touch each other. For instance, a first die may be coupled to a second die in a package even though the first die is never directly physically in contact with the second die.
One or more of the components, steps, features and/or functions illustrated in the figures may be rearranged and/or combined into a single component, step, feature or function or embodied in several components, steps, or functions. Additional elements, components, steps, and/or functions may also be added without departing from novel features disclosed herein. The apparatus, devices, and/or components illustrated in the figures may be configured to perform one or more of the methods, features, or steps described herein. The novel algorithms described herein may also be efficiently implemented in software and/or embedded in hardware.
It is to be understood that the specific order or hierarchy of steps in the methods disclosed is an illustration of exemplary processes. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the methods may be rearranged. The accompanying method claims present elements of the various steps in a sample order, and are not meant to be limited to the specific order or hierarchy presented unless specifically recited therein.
The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but are to be accorded the full scope consistent with the language of the claims, wherein 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. A phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover: a; b; c; a and b; a and c; b and c; and a, b and c. 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.”