One or more aspects of this disclosure relate generally to device packages. In particular, one or more aspects of this disclosure relate to device packages with wire bond assisted grounding and inductors.
Wire bond based devices are widely used for a large number of applications including digital, analog and RF (radio frequency).
There can be many wire bonds 120, and a significant number of them can be connected to the ground connector 170. Also, the wire bonds 120 are of different lengths. For example, the wire bonds 120 emanating from a center of the die 110 are generally longer than the wire bonds 120 emanating from a periphery of the die 110. Due to the different lengths of the wire bonds 120, there can be a huge range of wire bond inductances. Normally, such inductances are not desirable. Hence, they are referred to as “parasitic” inductances. Some parasitic inductance can be quite large, e.g., upto 2000 pH (picohenries) and more.
In the device package 200, the connections between the die 210 and the ground conductor 270 is accomplished with the TSVs 225. This can shorten the connection length between the die 210 and ground, and as a result, parasitic inductance can be significantly reduced. However, the device package 200 can be costly. This is because additional process or processes to incorporate the TSVs 225 is implemented.
This summary identifies features of some example aspects, and is not an exclusive or exhaustive description of the disclosed subject matter. Whether features or aspects are included in, or omitted from this summary is not intended as indicative of relative importance of such features. Additional features and aspects are described, and will become apparent to persons skilled in the art upon reading the following detailed description and viewing the drawings that form a part thereof.
An exemplary device package is disclosed. The device package may comprise a die on a package substrate, a mold also on the package substrate, an upper ground conductor on an upper surface of the mold, and a plurality of ground wire bonds within the mold. The die may comprise a plurality of terminals on an upper surface of the die. The mold may encapsulate the die. The plurality of ground wire bonds may electrically couple the die and the upper ground conductor. For each of the plurality of ground wire bonds, a first end of that ground wire bond may be electrically coupled to a corresponding terminal on the upper surface of the die, and a second end of that ground wire bond may be electrically coupled to the upper ground conductor at the upper surface of the mold.
An exemplary method of forming device package is disclosed. The method may comprise forming a die on a package substrate. The die may comprise a plurality of terminals on an upper surface of the die. The method may also comprise forming a mold on the package substrate. The mold may be formed so as to encapsulate the die. The method may further comprise forming an upper ground conductor on an upper surface of the mold. The method may further comprise forming a plurality of ground wire bonds within the mold such that the plurality of ground wire bonds electrically couple the die and the upper ground conductor. The plurality of ground wire bonds may be formed such that for each of the plurality of ground wire bonds, a first end of that ground wire bond is electrically coupled to a corresponding terminal on the upper surface of the die and a second end of that ground wire bond is electrically coupled to the upper ground conductor at the upper surface of the mold.
An exemplary device package is disclosed. The device package may comprise a die on a package substrate, a mold also on the package substrate, an upper ground conductor on an upper surface of the mold, and a wire bond inductor within the mold. The die may comprise a plurality of terminals on an upper surface of the die. The mold may encapsulate the die. The wire bond inductor may comprise a first wire bond, an inductance pad below an upper surface of the die, a second wire bond. A first end of the first wire bond may be electrically coupled to a terminal of the die. A second end of the first wire bond may be electrically coupled to the inductance pad. A first end of the second wire bond may be electrically coupled to the inductance pad. A second end of the second wire bond may be at the upper surface of the mold.
An exemplary device package is disclosed. The device package may comprise a die on a package substrate, means for encapsulating also on the package substrate, means for grounding on an upper surface of the means for encapsulating, and a plurality of ground wire bonds within the means for encapsulating. The die may comprise a plurality of terminals on an upper surface of the die. The means for encapsulating may encapsulate the die. The plurality of ground wire bonds may electrically couple the die and the means for grounding. For each of the plurality of ground wire bonds, a first end of that ground wire bond may be electrically coupled to a corresponding terminal on the upper surface of the die, and a second end of that ground wire bond may be electrically coupled to the means for grounding at the upper surface of the mold.
The accompanying drawings are presented to aid in the description of embodiments and are provided solely for illustration of the embodiments and not limitation thereof.
Examples are disclosed in the following description and related drawings directed to specific embodiments of one or more aspects of the present disclosure. Alternate embodiments may be devised without departing from the scope of the discussion. Additionally, well-known elements will not be described in detail or will be omitted so as not to obscure the relevant details.
The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments. Likewise, the term “embodiments” does not require that all embodiments of the disclosed subject matter include the discussed feature, advantage or mode of operation.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising,”, “includes” and/or “including”, when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
Further, many embodiments are described in terms of sequences of actions to be performed by, for example, elements of a computing device. It will be recognized that various actions described herein can be performed by specific circuits (e.g., application specific integrated circuits (ASICs)), by program instructions being executed by one or more processors, or by a combination of both. Additionally, these sequence of actions described herein can be considered to be embodied entirely within any form of computer readable storage medium having stored therein a corresponding set of computer instructions that upon execution would cause an associated processor to perform the functionality described herein. Thus, the various aspects may be embodied in a number of different forms, all of which have been contemplated to be within the scope of the claimed subject matter. In addition, for each of the embodiments described herein, the corresponding form of any such embodiments may be described herein as, for example, “logic configured to” perform the described action.
As mentioned, wire bond based device packages are widely used for a large number of applications. A large number of wire bonds can be provided between a device package and ground. Unfortunately, conventional wire bonds may have large parasitic inductances, which is undesirable. This can be addressed by using through-silicon vias (TSVs) for ground. Unfortunately, incorporating TSVs adds costs, which is also undesirable.
The device package 300 may further include a plurality of ground wire bonds 320. The plurality of ground wire bonds 320 may be within the mold 360 and may electrically couple the die 310 and the upper ground conductor 332. Each ground wire bond 320 may correspond with one of the terminals 315 on the upper surface of the die 310. That is, for each ground wire bond 320, a first end of that ground wire bond 320 may be electrically coupled to (e.g., in contact with) a corresponding terminal 315 and a second end of that ground wire bond 320 may be electrically coupled to (e.g., in contact with) the upper ground conductor 332 at the upper surface of the mold 360. In this way, the plurality of ground wire bonds 320 may provide paths to ground from the die 310.
Some ground wire bonds 320 may be substantially vertical. Preferably, each of the plurality of ground wire bonds 320 is substantially vertical. This is preferred since this would result in the length of the ground wire bonds 320 being as short as possible, which in turn reduces parasitic inductance. When compared to the conventional device package 200 illustrated in
Note that unlike the conventional device package 100 illustrated in
A corollary of the above-indicated advantage of the device package 300 is that some, i.e., one or more, of the ground wire bonds 320 can emanate from the interior of the die 310 and still have reduced parasitic inductance. This is explained with reference to
The terminal array 415 may be divided into a peripheral array 417 and an interior array 419 in which the peripheral array 417 surrounds the interior array 419. In
At least one ground wire bond 320 may correspond to an interior terminal 319 of the interior array 419 such that the first end of that ground wire bond 320 is in contact with the corresponding interior terminal 319 on the upper surface of the die 310. Of course, it is also within the scope of the disclosure that there are ground wire bond(s) 320 corresponding to peripheral terminal(s) 319. To reiterate, it is possible to have a ground wire bond 320 emanate from the interior of the die 310, i.e., correspond to an interior terminal 319, because the reduced parasitic inductance can be achieved substantially independently of the location of the ground wire bond 320.
It should be noted that the arrangement illustrated in
Referring back to
Recall from above that one significant advantage (of which there can be several) of the device package 300 is that the parasitic inductance can be reduced. However, there may be applications, e.g., degeneration applications, where high inductances are desirable. These include power amplifiers and low noise amplifiers. In
The WBIs 325 may include at least the following two types—terminal-ground (TG) and terminal-terminal (TT). One or both of types of WBIs 325 may serve as off-chip inductors that can replace on-chip inductors for achieving higher inductance values with improved Q factors.
The electrical couplings of the terminal-ground WBI 500 may be as follows: terminal 315⇄first wire bond 526⇄inductance pad 542⇄second wire bond 527⇄upper ground conductor 332. That is, for the first wire bond 526, a first end thereof may be electrically coupled to (e.g., in contact with) the terminal 315, and a second end thereof may be electrically coupled to (e.g., in contact with) the inductance pad 542. For the second wire bond 527, a first end thereof may be electrically coupled to (e.g., in contact with) the inductance pad 542, and a second end thereof may be electrically coupled to (e.g., in contact with) the upper ground conductor 332 at the upper surface of the mold 360. So as to minimize obfuscation, only a part of the upper ground conductor 332—the part in contact with the second wire bond 527—is shown.
For convenience, the first end of the first wire bond 526 may also be the first end of the terminal-ground WBI 500, and the second end of the second wire bond 527 may also be the second end of the terminal-ground WBI 500. With the first and second ends of the terminal-ground WBI 500 so defined, the following characterizations may be made. First, a portion of the terminal-ground WBI 500 between the first and second ends thereof may be below the terminal 315, i.e., below the upper surface of the die 310. Second, there may also be a portion of the terminal-ground WBI 500 between the first and second ends that is above the die 310. In
The electrical couplings of the terminal-terminal WBI 600 may be as follows: first terminal 315⇄first wire bond 626⇄first inductance pad 642⇄second wire bond 627⇄second inductance pad 643⇄third wire bond 628⇄third inductance pad 644⇄fourth wire bond 629⇄second terminal 315. That is, for the first wire bond 626, a first end thereof may be electrically coupled to (e.g., in contact with) the first terminal 315, and a second end thereof may be electrically coupled to (e.g., in contact with) the first inductance pad 642. For the second wire bond 627, a first end thereof may be electrically coupled to (e.g., in contact with) the first inductance pad 642, and a second end thereof may be electrically coupled to (e.g., in contact with) the second inductance pad 643 at the upper surface of the mold 360. For the third wire bond 628, a first end thereof may be electrically coupled to (e.g., in contact with) the second inductance pad 643, and a second end thereof may be electrically coupled to (e.g., in contact with) the third inductance pad 644. For the fourth wire bond 629, a first end thereof may be electrically coupled to (e.g., in contact with) the third inductance pad 644, and a second end thereof may be electrically coupled to (e.g., in contact with) the second terminal 315. The first terminal 315 and the second terminal 315 may be two different terminals 315 of the die 310. While not shown, it is within the scope of the disclosure that the first and second terminals 315 are terminals of different dies 310.
For convenience, the first end of the first wire bond 626 may also be the first end of the terminal-terminal WBI 600, and the second end of the fourth wire bond 629 may also be the second end of the terminal-terminal WBI 600. First, a portion of the terminal-terminal WBI 600 between the first and second ends may be below the upper surface of the die 310. Second, there may also be a portion of the terminal-terminal WBI 600 between the first and second ends that is above the die 310. In
While not illustrated, it is within the scope of this disclosure that first and third inductance pads be electrically coupled directly via one wire bond instead of the second wire bond 627, the second inductance pad 643, and the third wire bond 628. Such terminal-terminal WBI may be simpler to manufacture. The tradeoff may be that not as much inductance as the terminal-terminal WBI 600 may be provided.
In block 830, wire bonds for one or more terminal-ground WBIs 325, 500 may be formed. For each terminal-ground WBI 500, this may correspond to forming a pair of initial wire bonds 720 and 730. See
In block 840, wire bonds for one or more terminal-terminal WBIs 325, 600 may be formed. For each terminal-ground WBI 500, this may correspond to forming a group of two initial wire bonds 720 and two initial wire bonds 730. For the purpose of describing this block 840, one initial wire bond 720 will be referred to as the first initial wire bond 720, and the other will be referred to as the fourth initial wire bond 720. Also, one initial wire bond 730 will be referred to as the second initial wire bond 730, and the other will be referred to as the third initial wire bond 730. Then the first initial wire bond 720 of the group may be electrically coupled to (e.g., in contact with) a first terminal 315 on one end and electrically coupled to (e.g., in contact with) the first inductance pad 642 on another end. The second initial wire bond 730 of the group may be electrically coupled to (e.g., in contact with) the first inductance pad 642 and extend to a height at or above the threshold height. The third initial wire bond 730 of the group may be electrically coupled to (e.g., in contact with) the third inductance pad 644 and extend to a height at or above the threshold height. The fourth initial wire bond 720 of the group may be electrically coupled to (e.g., in contact with) the second terminal 315 on one end and electrically coupled to (e.g., in contact with) the third inductance pad 644 on another end. See also
It is not necessary to perform all of the blocks 820, 830, and 840. For example, if no terminal-terminal WBIs 600 are necessary, then block 840 need not be performed. This implies that the ground wire bonds 320, the terminal-ground WBIs 500, and the terminal-terminal WBIs 600 can be formed independently of each other.
Further, if and when any two or all three of the blocks 820, 830, and 840 are to be performed, they may be performed contemporaneously. As an illustration, if it is assumed that ground wire bonds 320 and terminal-ground WBIs 500 are to be formed, it is not necessary to completely perform block 820 before starting on block 830 or vice versa. In one aspect, the blocks may be performed simultaneously. In another aspect, a back-and-forth approach may be used, e.g., some wire bonds may be initially formed for the ground wire bonds 320 followed by forming some wire bonds for the terminal-ground WBIs 500, then followed by forming other wire bonds for the ground wire bonds 320, and so forth. The back-and-forth approach may be advantageous when routing of the initial wire bonds are taken into consideration.
In block 850, the mold 360 may be formed on the package substrate 380 so as to encapsulate the die 310. As seen in
In block 860, the mold 360 may be planarized to the threshold height as seen in
In block 870, a conductive material, e.g., copper, may be deposited on the mold 360 (and planarized if desired) to form the upper ground conductor 332 as seen in
If block 840 is performed, then in block 880, the upper ground conductor 332 may be selectively etched to form the second inductance pads 643 as seen in
Those of skill in the art will appreciate that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.
Further, those of skill in the art will appreciate that the various illustrative logical blocks, modules, circuits, and algorithms described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and methods have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.
The methods, sequences and/or algorithms described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor.
Accordingly, an embodiment can include a computer readable media embodying a method of forming a device package. Accordingly, the scope of the disclosed subject matter is not limited to illustrated examples and any means for performing the functionality described herein are included.
While the foregoing disclosure shows illustrative embodiments, it should be noted that various changes and modifications could be made herein without departing from the scope of the disclosed subject matter as defined by the appended claims. The functions, processes and/or actions of the method claims in accordance with the embodiments of the disclosed subject matter described herein need not be performed in any particular order. Furthermore, although elements of the disclosed subject matter may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated.