Patent Description:
Millimeter-wave systems, electronic systems that operate in the <NUM> to <NUM> gigahertz (GHz) frequency band, are utilized in a wide variety of applications including cellular communications (e.g., <NUM> networks), radio astronomy, military and civilian radar systems, security scanners, and medical imaging. The routing of millimeter-wave signals in a millimeter-wave system present unique challenges in the design and manufacturability of the system. Single-ended signals, that is, signals that are provided on a single signal trace and where the signal is provided with reference to a ground plane of the millimeter-wave system, are typically simpler to design and manufacture, but also typically have poorer performance characteristics as compared with balanced signals that are provided on two traces where the signal is carried as a differential signal between the traces. Millimeter-wave integrated circuits typically provide balanced signal inputs and outputs, and so, millimeter-wave systems that utilize single-ended signal routing also need a mechanism to convert the single-ended signals on the system to balanced signals for the integrated circuits. As such, a millimeter-wave system that utilizes single-ended routing will typically employ baluns, a transformer device, to perform the conversion and matching. However, baluns are bulky and consume a great deal of space on a printed circuit board (PCB). The use of baluns may be undesirable for certain types of millimeter-wave systems, such as cellphones and automotive radars, where space on a PCB is limited.

<CIT> relates to multi-layer high-speed ball grid array packages. <CIT>relates to electronic device and a method for manufacturing the electronic device, which comprises a plurality of interconnects for providing an electrically conductive connection between a packaged semiconductor chip and a substrate such as a printed circuit board. <CIT>relates to integrated circuit packages with integrated pre-match circuits. <CIT> relates to a communication device in which an antenna is incorporated in a semiconductor package.

According to a first aspect of the present disclosure, there is provided an integrated circuit device, comprising: an integrated circuit device die having a plurality of first contact pads, the plurality of first contact pads including a pair of first signal contact pads configured to provide a differential signal port of the integrated circuit device die, the differential signal port configured to operate at a predetermined frequency; and a substrate having a plurality of second contact pads on a first surface of the substrate, the second contact pads configured to be soldered to a printed circuit board, the plurality of second contact pads including a pair of second signal contact pads, wherein the integrated circuit device die is affixed to a second surface of the substrate via the first contact pads, wherein the substrate includes a pair of circuit paths, each circuit path configured to couple one of the first signal contact pads to an associated one of the second signal contact pads, and wherein the pair of circuit paths is further configured to provide a half-wave matching network at the predetermined frequency to match a single-ended signal at the pair of second signal pads to the differential signal port.

Each circuit path may include a first circuit trace on a first metallization layer on the second surface of the substrate.

Each circuit may path further include a via coupling the first circuit trace on the second surface of the substrate to the associated second contact pad on the first surface of the substrate.

The length may include a sum of a trace length of the first circuit trace and a via length of the via.

Each circuit path may further include a second circuit trace on a second metallization layer laminated within the substrate.

The predetermined frequency may be a millimeter-wave frequency in a range of <NUM> to <NUM>.

The length may be in a range between <NUM> millimeters and <NUM> millimeters.

The integrated circuit device may be one of a flip-chip device, an embedded wafer level packaging (eWLB) device, and a fan out wafer level packaging (FOWLP) device.

According to a second aspect of the present disclosure, there is provided a method, comprising: providing, on an integrated circuit device die of an integrated circuit device, a plurality of first contact pads, the plurality of first contact pads including a pair of first signal contact pads configured to provide a differential signal port of the integrated circuit device die, the differential signal port configured to operate at a predetermined frequency; providing, on a substrate of the integrated circuit device, a plurality of second contact pads on a first surface of the substrate, the second contact pads configured to be soldered to a printed circuit board, the plurality of second contact pads including a pair of second signal contact pads; affixing the integrated circuit device die to a second surface of the substrate via the first contact pads; and providing, on the substrate, a pair of circuit paths, each circuit path configured to couple one of the first signal contact pads to an associated one of the second signal contact pads, wherein the pair of circuit paths is further configured to provide a half-wave matching network at the predetermined frequency to match a single-ended signal at the pair of second signal pads to the differential signal port.

The method may further comprise: providing, in each circuit path, a first circuit trace on a first metallization layer on the second surface of the substrate.

The method may further comprise: providing, in each circuit path, a via coupling the first circuit trace on the second surface of the substrate to the associated second contact pad on the first surface of the substrate.

The method may further comprise: including a sum of a trace length of the first circuit trace and a via length of the via in the length
The method may further comprise: providing, in each circuit path further, a second circuit trace on a second metallization layer laminated within the substrate.

Each circuit path may include a first circuit trace on a first metallization layer on the second surface of the substrate and a via coupling the first circuit trace on the second surface of the substrate to the associated second contact pad on the first surface of the substrate, and the length may include a sum of a trace length of the first circuit trace and a via length of the via.

The predetermined frequency may be a millimeter-wave frequency in a range of <NUM> to <NUM>, and the length is in a range between <NUM> millimeters and <NUM> millimeters.

It will be appreciated that for simplicity and clarity of illustration, elements illustrated in the Figures have not necessarily been drawn to scale. Embodiments incorporating teachings of the present disclosure are shown and described with respect to the drawings presented herein, in which:.

The following description in combination with the Figures is provided to assist in understanding the teachings disclosed herein. The following discussion will focus on specific implementations and embodiments of the teachings. This focus is provided to assist in describing the teachings, and should not be interpreted as a limitation on the scope or applicability of the teachings. However, other teachings can certainly be used in this application. The teachings can also be used in other applications, and with several different types of architectures.

<FIG> illustrates a millimeter-wave system <NUM> including a printed circuit board (PCB) <NUM> and a radio frequency (RF) device <NUM>. Millimeter-wave system <NUM> represents a manufactured electronic product, such as a cellular communication devices (e.g., a <NUM> smartphone), a millimeter-wave radio device, a military or civilian radar system, a security scanner, a medical imaging device. Millimeter-wave system <NUM> may include elements of the design that operate in the <NUM> to <NUM> gigahertz (GHz) frequency band. PCB <NUM> includes a top metallization layer <NUM> that includes patterned traces that provide the circuit interconnections between the components of millimeter-wave system <NUM>, in accordance with a design of the millimeter-wave system. Hence, while top metallization layer <NUM> is depicted as a continuous layer, it will be understood that the top metallization layer is, in fact a patterned layer of metal material on the top surface of PCB <NUM>. The metal material will typically be understood to be copper, but other materials may be utilized, such as gold, silver, platinum, or other conductive materials, as needed or desired. Top metallization layer <NUM> is further depicted as including various contact pads (dotted line boxes) for attaching RF device <NUM>, and for providing electrical contacts between the RF device and PCB <NUM>. Printed circuit board <NUM> may be understood to include one or more additional patterned metallization layers laminated between insulating layers that are interconnected with metallization vias. The insulating layers may include FR4 material in accordance with various PCB standards, polyamide or Teflon laminates, or other materials as needed or desired. The design and manufacture of PCBs is known in the art and will not be further described herein except as needed to illustrate the current embodiments. It will be further understood that the metal traces may be on the surface of PCB <NUM>, such as microstrip traces, or may be between the insulating layers, such as stripline traces, as needed or desired.

RF device <NUM> includes a package substrate <NUM> and a RF device die <NUM>. Package substrate <NUM> includes solder balls <NUM> affixed to a bottom metallization layer <NUM> and connected by one or more via <NUM> to a top metallization layer <NUM>. Bottom and top metallization layers <NUM> and <NUM> are similar to top metallization layer <NUM> of PCB <NUM> in that top and bottom metallization layers <NUM> and <NUM> include patterned traces. However, here, the patterned traces and vias <NUM> that interconnect bottom metallization layer <NUM> and top metallization layer <NUM> provide the circuit interconnections between PCB <NUM> and RF device die <NUM> in accordance with a design of the RF device <NUM>. Hence, while bottom and top metallization layers <NUM> and <NUM> are depicted as continuous layers, it will be understood that the bottom and top metallization layers are, in fact patterned layers of metal material on the bottom and top surfaces of substrate <NUM>. The metal material will typically be understood to be copper, but other materials may be utilized, such as gold, silver, platinum, or other conductive materials, as needed or desired. Bottom and top metallization layers <NUM> and <NUM> are further depicted as including various contact pads (dotted line boxes) for attaching RF device <NUM> to PCB <NUM> and for attaching RF device die <NUM> to substrate <NUM>, and for providing electrical contacts between the RF device die and the PCB. Substrate <NUM> may be understood to include one or more additional patterned metallization layers laminated between insulating layers that are interconnected with metallization vias. The insulating layers may include FR4 material in accordance with various PCB standards, polyamide or Teflon laminates, or other materials as needed or desired. The design and manufacture of substrates is known in the art and will not be further described herein except as needed to illustrate the current embodiments. It will be further understood that the metal traces may be on the surface of substrate <NUM>, such as microstrip traces, or may be between the insulating layers, such as stripline traces, as needed or desired.

Solder balls <NUM> are applied to the contact pads on bottom metallization layer <NUM> in the manufacturing process of RF device <NUM>. When millimeter-wave system <NUM> is manufactured, RF device <NUM> is affixed to PCB <NUM> by applying heat sufficient to reflow solder balls <NUM> to make mechanical and electrical connections between the FR device and the PCB. RF device die <NUM> includes solder bumps <NUM> that are applied to a surface of the RF device die during a manufacturing process of the RF device die. Here, when RF device <NUM> is manufactured, RF device die <NUM> is affixed to substrate <NUM> by applying heat sufficient to reflow solder bumps <NUM> to make mechanical and electrical connections between the RF device die and the substrate. RF device <NUM> may be illustrative of various RF device packaging technologies, such as flip-chip device packaging, wire-bond packaging, embedded waver level packaging (eWLB), fan out wafer level packaging (FOWLP), or the like, as needed or desired. The design and manufacture of RF devices, and the packaging thereof, is known in the art and will not be further described herein except as needed to illustrate the current embodiments.

RF device die <NUM> represents an integrated circuit device that includes one or more millimeter-wave circuits, and may include one or more other circuits that are not necessarily millimeter-wave circuits. For example, RF device die <NUM> may represent a mixed signal (analog and digital) integrated circuit, digital signal processing circuit, or the like, as needed or desired. RF device die <NUM> is characterized by the fact that one or more set of solder bumps <NUM> carry millimeter-wave signals. The millimeter-wave signals may include millimeter-wave signal inputs to RF device die <NUM>, or millimeter-wave signal outputs from the RF device die. In a particular embodiment, RF device die <NUM> provides at least one of the millimeter-wave signals as a balanced pair, that is, where the millimeter-wave signal is provided on two adjacent solder bumps <NUM> that carry a differential signal between the solder bumps. In this regard, millimeter-wave system <NUM> illustrates a RF circuit trace <NUM> (illustrated as black area) that may be understood to be connected via blackened solder bump <NUM> to one or both of the balanced pair of millimeter-wave signals of RF device die <NUM>. Here, the second one of the balanced pair of millimeter-wave signals may be understood to not be visible in the illustration of <FIG>. RF circuit trace <NUM> is illustrated as being carried from RF device die <NUM> by a trace on top metallization layer <NUM>, through via <NUM>, to a contact pad in bottom metallization layer <NUM>, and through blackened solder ball <NUM> to a trace in top metallization layer <NUM>. The trace in top metallization layer <NUM> will be understood to be routed to another component (not illustrated) of millimeter-wave system <NUM>. RF circuit trace <NUM> may further be understood to traverse through one or more via similar to via <NUM> in substrate <NUM>, through one or more additional metallization layers in the substrate, and through one or more additional metallization layers in printed circuit board <NUM>, as needed or desired.

<FIG> illustrates substrate <NUM> including RF circuit trace <NUM>. RF signal trace <NUM> is illustrated as a pair of traces <NUM> and <NUM> that are routed on the top surface of substrate <NUM> to signal pads <NUM> that connect to the balanced pair of millimeter-wave signals from RF device die <NUM>. Each of traces <NUM> and <NUM> are configured to have substantially equal trace lengths from signal pads <NUM> to the associated solder balls on the bottom side of substrate <NUM>. In particular, traces <NUM> and <NUM> will each have a length given as: <MAT> where L is the total length of each of traces <NUM> and <NUM> from the associated signal pad <NUM> to the associated solder ball <NUM>, LT is the sum of the lengths of the traces traversed within the metallization layers of substrate <NUM>, and LV is the sum of the lengths of the vias traversed within the substrate.

In a particular embodiment, traces <NUM> and <NUM> are configured as a dual-mode matching network such that the millimeter-wave signal, as implemented on PCB <NUM>, may be alternatively a balanced signal or a single-ended signal, as needed or desired. In particular, where the millimeter-wave signal on PCB <NUM> is implemented as a balanced signal, the millimeter-wave signal matches with the millimeter-wave signals as provided on RF device <NUM>. That is, the millimeter-wave signal will have a low insertion loss because the millimeter-wave signal as provided on PCB <NUM> is a balanced and impedance matched signal like the millimeter-wave signal as utilized by RF device die <NUM>. Moreover, where the millimeter-wave signal on PCB <NUM> is implemented as a single-ended signal, traces <NUM> and <NUM> act as a matching network, such that the single-ended signal on the PCB can be connected directly to RF device <NUM> without the need of an additional balun.

<FIG> illustrates block diagrams <NUM> and <NUM>. In block diagram <NUM>, a <NUM> Ohm element <NUM> on PCB <NUM> is shown as being connected via traces <NUM> and <NUM> to a <NUM> ohm element <NUM> of RF device die <NUM>. Here, element <NUM> is configured as a balanced signal element. In block diagram <NUM>, element <NUM> is again shown as being connected via traces <NUM> and <NUM> to element <NUM>, where element <NUM> is configured as a single-ended signal element with one leg tied to a ground plane of PCB <NUM>.

Claim 1:
An integrated circuit device (<NUM>), comprising:
an integrated circuit device die (<NUM>) having a plurality of first contact pads, the plurality of first contact pads including a pair of first signal contact pads configured to provide a differential signal port of the integrated circuit device die, the differential signal port configured to operate at a predetermined frequency; and
a substrate (<NUM>) having a plurality of second contact pads on a first surface of the substrate, the second contact pads configured to be soldered to a printed circuit board (<NUM>), the plurality of second contact pads including a pair of second signal contact pads, wherein the integrated circuit device die is affixed to a second surface of the substrate via the first contact pads, wherein the substrate includes a pair of circuit paths (<NUM>, <NUM>), each circuit path configured to couple one of the first signal contact pads to an associated one of the second signal contact pads, and wherein the pair of circuit paths is further configured to provide a half-wave matching network at the predetermined frequency to match a single-ended signal at the pair of second signal pads to the differential signal port.