A radio frequency device having a radio frequency semiconductor die embedded within a substrate

Abstract

This disclosure relates to a radio frequency (RF) device having an RF semiconductor die embedded in a substrate. The RF device includes a substrate comprising a first layer, a second layer, and a metal structure. The RF device also includes an RF semiconductor die embedded in the substrate and surrounded by a material of the first layer of the substrate. The RF semiconductor die is coupled to the metal structure. The metal structure extends along a first direction parallel to a first surface of the substrate and a second direction perpendicular to the first surface of the substrate. The RF device also includes a waveguide antenna formed by the metal structure in the second layer of the substrate for transmitting RF signals from the RF semiconductor die to the outside of the RF device, or from the outside of the RF device to the RF semiconductor die.

Description

Technical Field

[0001] This disclosure relates to a radio frequency (RF) device having an RF semiconductor die embedded in a substrate. This disclosure also relates to a method of manufacturing such an RF device. Background Technology

[0002] Radio frequency (RF) devices are typically used to receive, transmit, and process RF signals. An RF device may have a packaged RF semiconductor die and a waveguide antenna mounted on a printed circuit board (PCB). The packaged RF semiconductor die and the waveguide antenna are mounted on the surface of the PCB. Specifically, the packaged RF semiconductor die is mounted on the PCB via an array of solder balls. The PCB has a transmitter or antenna configured to transmit and receive RF signals between the packaged RF semiconductor die and the waveguide antenna. The transmitter or antenna is coupled to the solder balls via microstrip lines. Due to thermal disturbances or stress between the PCB and the packaged RF semiconductor die, the solder balls may be damaged, affecting the integrity of the RF signal transmitted to the transmitter or antenna.

[0003] Furthermore, the packaged RF semiconductor die is encapsulated by a molded body. Therefore, the footprint of the packaged RF semiconductor die is larger than that of the RF semiconductor die itself. To increase the functionality of an RF device, the number of transmit / receive channels must be increased. This is achieved by mounting additional packaged RF semiconductor dies and additional waveguide antennas on the surface of a printed circuit board. Due to the limited surface area of ​​the printed circuit board, additional packaged RF semiconductor dies and waveguide antennas can present challenges, such as increased size or footprint of the RF device, increased cost due to the additional packaged RF semiconductor dies and waveguide antennas, electromagnetic interference between packaged RF semiconductor dies, and thermal management issues, all of which can significantly degrade the overall performance of the RF device.

[0004] There is a need to provide a radio frequency (RF) device that can achieve efficient transmission and reception of RF signals while minimizing signal loss, electromagnetic interference, and thermal issues, without significantly increasing the footprint of the RF device. Summary of the Invention

[0005] This disclosure relates to a radio frequency (RF) device including a substrate comprising a first layer, a second layer, and a metal structure. The RF device also includes an RF semiconductor die embedded within the substrate and surrounded by a material of the first layer of the substrate. The RF semiconductor die is coupled to the metal structure. The metal structure extends along a first direction parallel to a first surface of the substrate and a second direction perpendicular to the first surface of the substrate. The RF device also includes a waveguide antenna formed from the metal structure in the second layer of the substrate for transmitting RF signals from the RF semiconductor die to the outside of the RF device, or from the outside of the RF device to the RF semiconductor die.

[0006] This disclosure also relates to a method of forming a radio frequency (RF) device including an RF semiconductor die embedded in a substrate. The method includes: providing a substrate layer; attaching a first surface of the RF semiconductor die to a surface of the substrate layer; depositing a material over the surface of the substrate layer to form a first layer of the substrate such that the RF semiconductor die is surrounded by the material; and forming a second layer of the substrate over the first layer, wherein forming the second layer includes forming a metal structure, and wherein a first segment of the metal structure forms a waveguide antenna.

[0007] This disclosure relates to a radio frequency (RF) device including a substrate comprising a first layer and a metal structure. The RF device also includes a bare RF semiconductor die embedded within the substrate. The bare RF semiconductor die is surrounded and in contact with a material of the first layer of the substrate. The metal structure extends along a first direction parallel to a first surface of the substrate. The RF device also includes a waveguide antenna mounted above the first surface of the substrate for transmitting RF signals from the bare RF semiconductor die to the outside of the RF device via the metal structure, or from the outside of the RF device to the bare RF semiconductor die via the metal structure.

[0008] Other features and advantages will be recognized by those skilled in the art upon reading the following detailed description and viewing the accompanying drawings. Attached Figure Description

[0009] This disclosure is illustrated in the accompanying drawings by way of example rather than limitation, and similar reference numerals in the drawings refer to similar or identical elements. Elements in the drawings are not necessarily drawn to scale. Features of the various examples can be combined unless mutually exclusive.

[0010] Figure 1 An example of a radio frequency (RF) device is illustrated, having an RF semiconductor die embedded in a substrate and a waveguide antenna formed in the substrate.

[0011] Figure 2 An example of another RF device with a transmitter inside the substrate is illustrated.

[0012] Figure 3The illustration shows an example of another RF device with an air-filled waveguide antenna formed within a substrate.

[0013] Figure 4 The diagram shows Figure 3 Another example of an RF device, in which the opening of the air-filled waveguide antenna is covered by a layer of substrate.

[0014] Figure 5 The illustration shows an example of another RF device in which the metal structure of the substrate has a through-hole that separates a first part and a second part of the waveguide antenna.

[0015] Figure 6 The illustration shows an example of another RF device with a molded RF semiconductor die embedded in a substrate.

[0016] Figure 7 The illustration shows an example of another RF device having a semiconductor die coupled to a metal structure of the substrate of the RF device.

[0017] Figure 8 The illustration shows an example of another RF device, in which the metal structure of the substrate includes a heat sink.

[0018] Figure 9 The illustration shows an example of another RF device with multiple RF semiconductor dies coupled to transmission waveguides via waveguide antennas.

[0019] Figure 10 The illustration shows an example of an RF device with multiple electrical contact pads.

[0020] Figure 11A-11D The illustration shows various steps of a method for forming an RF device having an RF semiconductor die embedded in a substrate and a waveguide antenna formed in a substrate.

[0021] Figures 12A-12C The illustration shows further steps of the method in Figure 11, wherein the transmitter is formed within the substrate and coupled to an RF semiconductor die.

[0022] Figures 13A-13B The illustration shows a further step of the method of Figure 11, wherein a separating via is formed in the second layer of the substrate to separate the two different parts of the waveguide antenna.

[0023] Figure 14 An alternative step to one of the steps in the method of Figure 11 is illustrated, wherein a molded RF semiconductor die is attached to a substrate.

[0024] Figure 15 An example of a radio frequency (RF) device is illustrated, having a bare RF semiconductor die embedded in a substrate and a waveguide antenna mounted on the substrate.

[0025] Figure 16 The illustration shows an example of another RF device with a bare RF semiconductor die that includes a transmitter.

[0026] Figure 17 The illustration shows an example of another RF device with multiple transmission waveguide couplings via waveguide antennas. Detailed Implementation

[0027] The embodiments described herein provide a novel concept for a radio frequency (RF) device. Currently, the industry is seeking solutions to increase the functionality of RF devices without significantly increasing their footprint and cost. The embodiments described herein allow for improved RF device design. The RF device has a substrate comprising a first layer, a second layer, and a metal structure. An RF semiconductor die is embedded within the substrate and surrounded by the material of the first layer of the substrate. The RF semiconductor die is coupled to the metal structure, and the metal structure extends along a first direction parallel to a first surface of the substrate and a second direction perpendicular to the first surface of the substrate. A waveguide antenna is formed from the metal structure in the second layer of the substrate for transmitting RF signals from the RF semiconductor die to the outside of the RF device, or from the outside of the RF device to the RF semiconductor die. By embedding the RF semiconductor die within the substrate and forming the waveguide antenna within the substrate, the overall footprint of the RF device can be reduced compared to conventional RF devices. Furthermore, the signal path from the RF semiconductor die to the waveguide antenna can be shortened, thereby reducing transmission loss. Meanwhile, coupling to the waveguide antenna can become more reliable and efficient because the coupling structure can be formed in the same way as the waveguide antenna, without any additional soldering or mounting, resulting in more uniform and reliable transmission to the waveguide antenna. Furthermore, for a given substrate size, this RF device can have a greater number of transmit / receive channels compared to conventional RF devices. Overall, production costs can also be reduced because the packaging of the RF semiconductor die, the formation and connection to the substrate (such as a printed circuit board), and the fabrication of the waveguide antenna are integrated into a single manufacturing process.

[0028] Figure 1An example of a radio frequency (RF) device 100 is shown. The RF device 100 has an RF semiconductor die 110 and a substrate 102. The substrate 102 has a first layer 104, a second layer 106, and a metal structure 108. In the example described herein, the substrate 102 may be a printed circuit board (PCB) into which the RF semiconductor die 110 is embedded. The first layer 104 and the second layer 106 may be vertically stacked such that the second layer 106 is positioned above the first layer 104. The second layer 106 may be the outermost layer of the substrate 102. The outermost surface of the second layer 106 forms a first surface 112 of the substrate 102, which may be a first primary surface. The first layer 104 may include a material 104a for forming the printed circuit board (PCB), such as, but not limited to, FR4, epoxy resin, polymer materials, prepreg, or Ajinomoto multilayer film (ABF) material. The metal structure 108 may extend along a first direction D1 and a second direction D2. A first direction D1 is parallel to a first surface 112 of substrate 102, and a second direction D2 is perpendicular to the first surface 112 of substrate 102. The metal structure 108 may include, for example, but not limited to, aluminum, copper, silver, gold, or alloys thereof. Furthermore, the metal structure 108 may include through-holes for forming vertical structures and / or plates for forming horizontal structures. In the example described herein, the plate is formed of metal layers of a printed circuit board, and the through-holes are vias extending between the metal layers in the printed circuit board. The metal structure 108 may extend in the first layer 104 and the second layer 106, and may also extend between the first layer 104 and the second layer 106. The metal structure 108 may extend on the first surface 112 and the opposing second surface 120 of substrate 102.

[0029] In one example, the first layer 104 may be surrounded by another material, such as, but not limited to, FR4, epoxy resin, polymer material, prepreg or Ajinomoto laminate (ABF) material, particularly in the first direction D1.

[0030] As described herein, RF device 100 includes an RF semiconductor die 110. The RF semiconductor die 110 may have, among other things, RF front-end circuitry, such as an RF oscillator, amplifier, and mixer, and baseband (and / or intermediate frequency (IF) band) circuitry, such as amplifiers and analog filters. Furthermore, the RF semiconductor die 110 may include an analog-to-digital converter for digitizing the baseband or IF band signal. The RF semiconductor die 110 can operate at frequencies selected from the range of 1 GHz to 500 GHz. In some examples, the RF semiconductor die 110 can operate within the following frequency ranges, including but not limited to microwave frequencies of 1 GHz to 30 GHz, millimeter-wave frequencies of 30 GHz to 300 GHz, and submillimeter-wave frequencies of 300 GHz to 500 GHz. Front-end circuitry is formed on the front side 118 of the RF semiconductor die 110. In some examples, the front side 118 of the RF semiconductor die 110 faces a first surface 112 of the substrate 102. The RF semiconductor die 110 may have one or more channels configured to transmit or receive RF signals. The RF semiconductor die 110 may be a radar monolithic microwave integrated circuit (MMIC).

[0031] The RF semiconductor die 110 includes a chip-integrated antenna or chip-integrated transmitter 122 formed directly on the RF semiconductor die 110, particularly on the front side 118 of the RF semiconductor die 110. In some examples, the chip-integrated antenna or chip-integrated transmitter 122 may include a patch antenna or transmitter structure formed in a metal layer of the RF semiconductor die 110. The chip-integrated antenna or chip-integrated transmitter 122 may be coupled to an RF channel via a waveguide or microstrip. The chip-integrated antenna or chip-integrated transmitter 122 of the RF semiconductor die 110 may transmit RF signals from the RF semiconductor die 110 or receive RF signals from outside the RF semiconductor die 110. The chip-integrated antenna or chip-integrated transmitter 122 may be formed during the manufacturing process of the RF semiconductor die 110 and may also be precisely formed at a desired location on the RF semiconductor die 110. The chip-integrated antenna or chip-integrated transmitter 122 can wirelessly transmit RF signals, thereby enhancing RF signal integrity and reducing RF signal loss. The chip-integrated antenna or chip-integrated transmitter 122 can be used with the RF semiconductor die 110 that operates at submillimeter wave frequencies.

[0032] As described herein, RF device 100 includes an RF semiconductor die 110. A back side 116 of the RF semiconductor die 110 may be disposed above the surface of an inner portion of a metal structure 108 in a first layer 104, wherein the back side 116 is opposite to the front side 118 of the RF semiconductor die 110. A material 104a of the first layer 104 surrounds the RF semiconductor die 110. The thickness of the material 104a of the first layer 104 above the front side 118 of the RF semiconductor die 110, measured in a second direction D2, may be less than 50 μm. Therefore, a chip-integrated antenna or chip-integrated transmitter 122 can transmit or couple RF signals without significant signal loss due to the material 104a of the first layer 104.

[0033] Waveguide antenna 114 is implemented in a second layer 106. The thickness of the second layer 106 can range from 10 μm to 1000 μm, particularly 50 μm to 500 μm, and especially 100 μm to 300 μm measured in the second direction D2. Waveguide antenna 114 is formed from a metal structure 108 in the second layer 106. Waveguide antenna 114 is configured to transmit RF signals from RF semiconductor die 110 to the outside of RF device 100 and vice versa. Specifically, waveguide antenna 114 has a bottom wall 124 and an opposing top wall 134, which are connected by side walls 136 of waveguide antenna 114, as shown below. Figure 1 The image is shown as a dashed rectangle. In one example, the bottom wall 124 of the waveguide antenna 114 may be located at the interface between the first layer 104 and the second layer 106, while the top wall 134 of the waveguide antenna 114 may be located at the first surface 112 of the substrate 102. The waveguide antenna 114 also has an inner opening 126 and an outer opening 128. The inner opening 126 faces the front side 118 of the RF semiconductor die 110, particularly the chip-integrated antenna or chip-integrated transmitter 122, allowing RF signals to be coupled between the RF semiconductor die 110 and the waveguide antenna 114. The outer opening 128 extends to the first surface 112 of the substrate 102 and couples RF signals between the waveguide antenna 114 and the outside of the RF device 100. In some examples, the outer opening 128 forms a radiating or receiving element for transmitting or receiving signals from the outside. In some examples, the outer opening 128 may be in the form of a slit. The waveguide antenna 114 can be configured to transmit signals from the outer opening of the waveguide antenna to the chip-integrated antenna or the chip-integrated transmitter 122 in at least one of the TEM, TM, or TE modes, or to transmit signals from the chip-integrated antenna or the chip-integrated transmitter 122 to the outer opening of the waveguide antenna.

[0034] In one example, waveguide antenna 114 may be a dielectric-filled hollow waveguide antenna. The second layer 106 may include a dielectric material 130 that fills the internal volume of waveguide antenna 114. Dielectric material 130 may include low-loss materials, such as, but not limited to, glass, epoxy resin, resin, polytetrafluoroethylene, etc. Therefore, RF signals propagating within waveguide antenna 114 can be transmitted without significant loss. Using dielectric material 130 allows for better sizing of the waveguide antenna to the operating frequency of RF device 100. Dielectric material 130 is provided using well-known techniques, such as, but not limited to, lamination processes, deposition, molding, or other techniques, which makes the embedding process (i.e., the formation of the stack of layers 104, 106) simple and cost-effective.

[0035] Optionally, the RF semiconductor die 110 may have electrical contact pads 132 on its front side 118. The RF semiconductor die 110 is electrically coupled to the metal structure 108 via the electrical contact pads 132. The electrical contact pads 132 are configured to provide electrical connections to the RF semiconductor die 110 for transmitting power and / or other signals (e.g., measurement signals) to, or receiving signals from, other components integrated or mounted on the substrate 102. An electrical contact structure 138 may be electrically coupled to the electrical contact pads 132. The electrical contact structure 138 is formed from the metal structure 108. In one example, a portion of the electrical contact structure 138 and the inner wall 124 of the waveguide antenna 114 may be fabricated by selectively etching the same segment of the metal structure 108. Thus, this portion of the electrical contact structure 138 and the inner wall 124 of the waveguide antenna 114 may be aligned in the same plane parallel to the first direction D1.

[0036] The novel concept provides an RF device with a substrate 102 having a first layer 104 and a second layer 106. An RF semiconductor die 110 and a waveguide antenna 114 are integrated within the substrate 102. Using a multi-layered substrate 102 allows for the integration of multiple components, namely, the RF semiconductor die 110 embedded in the first layer 104 and the waveguide antenna 114 formed by a metal structure 108 in the second layer 106. In other words, the substrate 102 can be used to route electrical and RF signals in the RF device 100. The novel concept allows for the integration of the RF semiconductor die 110 and the waveguide antenna 114 using the internal volume of the substrate 102. Integration of the RF semiconductor die 110, in examples, involves fully embedding the RF semiconductor die 110 such that the material of the substrate 102 surrounds the RF semiconductor die 110 on all sides. In some examples, the material of the substrate 102 contacts the RF semiconductor die 110 on all sides. Therefore, more space is available on the surfaces 112, 120 of substrate 102, allowing for the mounting of other components, such as capacitors, inductors, or resistors. For a given volume of substrate 102, RF device 100 can have more RF semiconductor dies 110 compared to conventional RF devices, thus providing more transmission / reception channels. By forming waveguide antenna 114 within substrate 102, the RF signal path from RF semiconductor die 110 to the radiating / receiving element is shortened. Furthermore, the RF signal is transmitted wirelessly directly to waveguide antenna 114 without the need for solder ball grid arrays and microstrip lines, resulting in more uniform and reliable RF signal transmission to the waveguide antenna. Therefore, the risk of signal loss and degradation due to damage to solder ball grid arrays and microstrip lines can be completely avoided. Moreover, the use of waveguide antenna 114 formed from the metal structure 108 of substrate 102 eliminates the need for an external waveguide antenna, making the RF device more compact and cost-effective.

[0037] Figure 2 Another example of an RF device 200 is shown. The RF device 200 may include... Figure 1 Some or all of the features of RF device 100 will be described only for the differences. For brevity, electrical contact pads are not shown in RF device 200. RF signals can be transmitted between RF semiconductor die 110 and waveguide antenna 114 via transmitter 202 formed by metal structure 108, rather than via chip-integrated antenna or chip-integrated transmitter in RF semiconductor die 110. RF semiconductor die 110 has RF contact pads 206 on its front side 118, which are coupled to channels of RF semiconductor die 110.

[0038] The emitter 202 is located inside the substrate 102. For example... Figure 2As shown, a segment 204 of the metal structure 108 forms a transmitter 202. The transmitter 202 is mounted on an RF contact pad 206, thereby coupling to a channel of the RF semiconductor die 110. The transmitter 202 includes a via 202a and a transmitter pad 202b. The via 202a may be partially located in the first layer 104, while the transmitter pad 202b is located in the second layer 106. The transmitter pad 202b and the inner wall 124 of the waveguide antenna 114 may be aligned to the same plane parallel to the first direction D1. Specifically, the inner wall 134 of the waveguide antenna 114 and the transmitter pad 202b may be formed by selectively etching the same segment of the metal structure 108. The transmitter 202 may directly couple RF signals to the waveguide antenna 114 formed in the second layer 106, and vice versa. Transmitter 202 can be used in applications using millimeter-wave frequencies or lower frequency RF signals whose wavelengths are greater than the dimensions of RF semiconductor die 110 (measured between opposite sides of RF semiconductor die 110 in a direction perpendicular to the first surface 112 of substrate 102). However, the use of transmitter 202 is not limited to the applications described above. Transmitter 202 can improve coupling to waveguide antenna 114, thereby reducing electromagnetic interference to RF semiconductor die 110.

[0039] In another example of RF device 300, waveguide antenna 114 can be as follows: Figure 3 The air-filled waveguide antenna shown is an example of an air-filled waveguide antenna 114. By using an air-filled waveguide antenna 114, losses caused by the dielectric material 130 in the waveguide antenna 114 can be avoided.

[0040] Figure 4 Another example of an RF device 400 with an air-filled waveguide antenna 114 is shown. The RF device 400 may include... Figures 1 to 3 The RF devices 100, 200, and 300 have some or all of their features, and the following description will focus only on the differences. Substrate 102 has a third layer 402 extending along a first direction D1. The third layer 402 may be disposed within the second layer 106 such that the third layer 402 is located within the internal volume of the waveguide antenna 114. Alternatively, the third layer 402 may be disposed above the first surface 112 of substrate 102. The third layer 402 may be configured to cover the external opening 128 of the waveguide antenna 114. The material of the third layer 402 may include glass, epoxy resin, resin, polytetrafluoroethylene, etc. The material of the third layer 402 is transparent to RF signals. The third layer 402 acts as a barrier to prevent external factors such as moisture, dust, or other contaminants from entering the waveguide antenna 114, thereby protecting the RF semiconductor die 110 from external influences.

[0041] In one example, the third layer 402 within the outer opening 128 can be selectively etched to expose the outer opening 128 of the waveguide antenna 114.

[0042] Figure 5 Another example of an RF device 500 having more than one RF channel and more than one transmitter is shown. The RF device 500 may include... Figure 4 The following describes some or all of the features of the RF device 400, focusing only on the differences. Figure 5 The waveguide antenna 114 shown is filled with dielectric material 130, but it should be understood that in other examples, the waveguide antenna 114 may include an air-filled waveguide antenna 114c.

[0043] The RF semiconductor die 110 may have multiple RF channels operating in the same or multiple frequency bands. Therefore, the RF device 500 may have multiple transmitters 202, 502, such that each of the multiple transmitters 202, 502 is coupled to a corresponding RF channel among the multiple RF channels of the RF semiconductor die 110. The transmitter 202 and the channel may be referred to as a first transmitter 202 and a first channel, respectively. The RF device 500 may have a second transmitter 502 coupled to a second channel of the RF semiconductor die 110. The first transmitter 202 is coupled to a first portion 114a of the waveguide antenna 114, and the second transmitter 502 is coupled to a second portion 114b of the waveguide antenna 114. In other words, the first transmitter 202 couples the RF signal associated with the first channel of the RF semiconductor die 110 to the first portion 114a of the waveguide antenna 114, while the second transmitter 502 couples the RF signal associated with the second channel of the RF semiconductor die 110 to the second portion 114b of the waveguide antenna 114. The first portion 114a and the second portion 114b of the waveguide antenna 114 are separated by a separating via 504. In some examples, another segment of the metal structure 108 forms the separating via 504. The separating via 504 extends along a second direction D2. The separating via 504 can also extend into the first layer 104 and can be coupled to the front side 118 of the RF semiconductor die 110. Specifically, the separating via 504 is mechanically coupled to the ground pad 506 of the RF semiconductor die 110. Furthermore, the separating via 504 is located between the first transmitter 202 and the second transmitter 502. The separating via 504 can reflect RF signals, thereby avoiding interference between RF signals in the first portion 114a and the second portion 114b of the waveguide antenna 114. Therefore, interference between RF signals transmitted by the respective transmitters 202, 504 within the waveguide antenna 114 can be significantly reduced, and RF channels can be separated.

[0044] In one example, an electrical contact structure or other contact structure made of another section of the metal structure 108 can be coupled to the grounding pad 506, and the separating via 504 is mechanically coupled to the contact structure.

[0045] Figure 5 An example is shown with two transmitters 202, 502 and two portions 114a, 114b of a waveguide antenna 114 separated by a separating via 504. It should be understood that the RF device 500 may have more than two transmitters. Each transmitter is coupled to a corresponding transmission line of the RF semiconductor die 110 and a corresponding portion of the waveguide antenna 114. The different portions of the waveguide antenna 114 are separated by corresponding separating vias.

[0046] In one example, RF device 500 may have, for example: Figure 1 Instead of transmitters 202, 502 formed of a metal structure, the two chip-integrated antennas or chip-integrated transmitters are integrated within the RF semiconductor die 110. Each chip-integrated antenna or chip-integrated transmitter can be coupled to a corresponding channel of the RF semiconductor die 110 and corresponding portions 114a, 114b of the waveguide antenna 114 to transmit RF signals between them. The separating via 504 can be directly coupled to the ground contact pad 506, thereby avoiding interference between RF signals transmitted from the chip-integrated antenna or chip-integrated transmitter to different portions of the waveguide antenna 114.

[0047] Figure 6 Another example of an RF device 600 having a molded RF semiconductor die 610 is shown. The RF device 600 may include... Figure 5 The following description will focus on the differences between some or all of the features of the RF device 500. In the RF device 600, the RF semiconductor die 110 is surrounded by a molding compound 602 before being embedded within the substrate 110. The molding compound 602 can protect the RF semiconductor die 110 from mechanical damage and contamination from external factors such as moisture, dust, or other contaminants during embedding. The RF semiconductor die 110 with the molding compound 602 forms a molded semiconductor die 610. The molding compound 602 may include, for example, but not limited to, epoxy resin, resin, etc. A material 104a of the first layer 104 surrounds the molding compound 602.

[0048] The molded RF semiconductor die 610 includes a transmitter 604 integrated within a molding body 602. The transmitter 604 is coupled to the RF contact pads 206 of the RF semiconductor die 110 and via a redistribution layer ( Figure 6 (Not shown) Coupled with a corresponding channel of the RF semiconductor die 110. The transmitter 604 is located in the fan-out region of the molded RF semiconductor die 610. The molded RF semiconductor die 610a with the transmitter 604 in the fan-out region allows for an increase in the contact area of ​​the transmitter 604, since the width of the transmitter 604 is not limited by the width of the RF semiconductor die 110. This further simplifies the process of embedding the RF semiconductor die 110 within the substrate 102.

[0049] In one example, the molded RF semiconductor die 610 may have at least two transmitters 604 and a ground contact pad 606 located between the transmitters 604. Each transmitter 604 is coupled to a corresponding portion 114a, 114b of the waveguide antenna 114. The ground contact pad 606 may be coupled to a contact structure 608. The contact structure 608 may be located in a redistribution layer and exposed from the molding body 602. A separating via 504 may be mechanically coupled to the contact structure 608 of the molded RF semiconductor die 610, thereby separating the first portion 114a and the second portion 114b of the waveguide antenna, ultimately isolating the transmitters 604 from each other.

[0050] In one example, the separator via 504 can be mechanically coupled to the molded body 602 instead of to the ground contact pad 606.

[0051] Figure 7 Another example of an RF device 700 is shown, which, in addition to the RF semiconductor die 110, also has a semiconductor die 702. The RF device 700 may include... Figure 6 The RF device 600 includes some or all of the features of the RF device 600, which will be described below only for differences. The RF device 700 includes a semiconductor die 702 electrically and mechanically coupled to a metal structure 108. The metal structure 108 electrically couples the RF semiconductor die 110 and the semiconductor die 702. The semiconductor die 702 may be embedded within a substrate 102. For example, the semiconductor die 702 may be disposed on the metal structure 108 within layers 104, 106 of the substrate 102. Alternatively, the semiconductor die 702 may be disposed on the substrate 102. For example, as... Figure 7 As shown, the semiconductor die can be disposed outside the substrate 102, that is, on a portion of the metal structure 108 extending onto the surfaces 112, 120 of the substrate 102. The semiconductor die 702 can be as follows: Figure 6 The packaged semiconductor die shown is shown. Semiconductor die 702 can be a power management die, allowing for optimized power consumption so that the RF device 700 can operate within stable and reliable power limits. Alternatively, semiconductor die 702 can be a microcontroller, allowing the RF device 700 to perform computational or control operations, such as, but not limited to, data processing, signal processing, or signal control. Semiconductor die 702 can be flexibly integrated into the RF device 700, i.e., it can be inside or outside the substrate 102.

[0052] Figure 8 Another example of an RF device 800 is shown, which has a heat sink 802 formed within a substrate 102. The RF device 800 may include... Figure 7The following description will focus on the differences between some or all of the features of the RF device 700. The metal structure 108 includes a heat sink 802, which can be considered as a metal block. The heat sink 802 is disposed between the back side 116 of the RF semiconductor die 110 and the second surface 120 of the substrate 102. The heat sink 802 is thermally coupled to the RF semiconductor die 110, so that the heat generated by the RF semiconductor die 110 is effectively transferred to the outside of the RF device 100. Therefore, heat transfer is improved, and the performance and reliability of the RF device 800 can be enhanced. The heat sink 802 may be exposed from the substrate 102, for example, from the second surface 120. The heat sink 802 may be thermally coupled to another heat sink for heat dissipation, thereby further increasing heat transfer from the RF semiconductor die 110.

[0053] Figure 9 Another example of an RF device 900 is shown, which has more than one RF semiconductor die coupled to each other. For example, these RF semiconductor dies can form a cascaded system. RF device 900 may include... Figure 8 The RF device 800 will have some or all of its features described below, focusing only on the differences. The RF device 900 may have another RF semiconductor die 910. RF semiconductor die 110 may be a primary RF semiconductor die 110, while the other RF semiconductor die may be a secondary RF semiconductor die 910. As described above, the primary RF semiconductor die 110 includes transmitters 202, 502, each of which is coupled to a corresponding RF channel of the primary semiconductor die 110. The secondary RF semiconductor die 910 is also surrounded by material 104a of the first layer 104 and coupled to the metal structure 108 and the waveguide antenna 114. Similar to the primary RF die 110, the secondary RF semiconductor die 910 includes a first transmitter 902 and a second transmitter 904, each of which is coupled to a corresponding RF channel of the secondary RF semiconductor die 910. Each transmitter 202, 502, 902, 904 of the primary RF semiconductor die 110 and the secondary RF semiconductor die 910 is coupled to a dedicated portion of the waveguide antenna 114. For example... Figure 9 As further shown, the first transmitter 202 of the primary RF semiconductor die 110 is coupled to the first portion 114a, while the first transmitter 902 of the secondary RF semiconductor die 910 is coupled to another portion 114c of the waveguide antenna 114. Portions 114a and 114c of the waveguide antenna 114 are separated by separating vias 504 and 912.

[0054] Furthermore, the second transmitter 502 of the primary RF semiconductor die 110 is coupled to the second transmitter 904 of the secondary RF semiconductor die 910 via the transmission waveguide 906 of the waveguide antenna 114. The transmission waveguide 906 is configured to transmit a local oscillator (LO) signal from the primary RF semiconductor die 110 to the secondary RF semiconductor die 910 via transmitters 502 and 910, thereby achieving synchronization between the primary and secondary RF semiconductor dies 110. This allows the primary and secondary RF semiconductor dies 110 and 910 to operate using a common LO signal generated by the local oscillator of the primary RF semiconductor die 110. This synchronization of operation between the primary and secondary RF semiconductor dies 110 is achieved through the transmission waveguide 906 of the waveguide antenna 114.

[0055] Although Figure 9 A transmission waveguide 906 for transmitting LO signals is shown, but in other examples, the transmitters 502, 902 of the respective RF semiconductor dies 110, 910 can be coupled by one or more metal lines (e.g., strip lines), wherein the metal lines are formed by metal structures 108.

[0056] Figure 10 Another example of an RF device 1000 is shown, which includes a semiconductor die 110. The RF semiconductor die 110 includes a plurality of electrical contact pads 132 coupled to corresponding electrical contact structures 138. The pitch dimension P of each electrical contact pad 132 is less than 250 μm. This pitch dimension P is the center-to-center distance between the electrical contact pad 132 and the chip-integrated transmitter or chip-integrated antenna 122. Each electrical contact pad 132 is coupled to a metal structure 108 of a substrate 102 to provide a direct and efficient path for electrical signals to the RF semiconductor die 110. The pitch dimension P can be between 50 μm and 250 μm, particularly 100 μm to 200 μm, and particularly 70 μm to 120 μm, providing high-density electrical connections. It should be noted that the electrical contact structures 138, as part of the metal structure 108, are configured to be connected to each electrical contact pad 132 respectively. Accordingly, the metal structure 108 includes connection structures (e.g., vias) with the same pitch as the electrical contact pads 132. In other words, the metal structure 108 can be used to route electrical signals and transmit RF signals, thus allowing the RF device 1000 to be made more compact and integrated. More specifically, by providing the metal structure 108 with connection structures having a small pitch P, the RF semiconductor die 110 is allowed to become a highly integrated IC, such as a radar MMIC with numerous receive and transmit channels.

[0057] In some examples, the pitch dimension P is the center-to-center distance between the electrical contact pad 132 and the transmitter 202.

[0058] Figures 11A to 11D The diagram illustrates the formation Figures 1 to 10 The method 1100 for the RF device described herein comprises various steps. In some examples, the method utilizes chip embedding technology, employing PCB manufacturing process steps such as lamination. In one example, chip embedding can use a chip-first method as described below. In other examples, a chip-post method can be used. For method 1100 and... Figures 1 to 10 Identical or similar features between RF devices will use the same reference notation. For example... Figure 11A As shown, a substrate layer 1102 is provided. This substrate layer 1102 can be a metal layer or a dielectric layer, or a layer stack structure including both metal and dielectric layers. Figure 11B As shown, the back side 116 of the RF semiconductor die 110 is disposed on the surface 1106 of the substrate layer 1102. In this example, the chip is placed face up, but in other examples, a chip-down method can be used. An adhesive material can be disposed between the back side 116 of the RF semiconductor die 110 and the surface 1106 of the substrate layer 1102. This adhesive material can be, for example, but not limited to, epoxy-based adhesives or silicone-based adhesives, and its thickness ranges from 1 μm to 10 μm, which is measured vertically between the back side 116 of the RF semiconductor die 110 and the surface 1106 of the substrate layer 1102. The thickness of the RF semiconductor die 110 can be in the range of 50 μm to 100 μm, which is measured between the front side 118 of the RF semiconductor die 110 and the opposite back side. Figure 11C As shown, material 104a is provided on the surface 1106 of substrate 1102 to form a first layer 104 of substrate 102, such that RF semiconductor die 110 is embedded and surrounded by material 104a. Material 104a can be provided, for example, using a lamination process in which a layer or stack of layers comprising material 104a, including the first layer 104, is placed on the RF semiconductor die 110, and heat and pressure are applied to embed the RF semiconductor die 110 within the first layer 104. In other examples, deposition, molding, or other techniques can be used. In some examples, material 104a may include at least one material selected from polymer materials, prepreg materials, and Ajinomoto multilayer film materials.

[0059] Alternatively, the substrate 1102 may be provided with a material such as a prepreg, and the prepreg may be partially removed by laser etching or chemical etching to expose the substrate 1102 from the prepreg. Then, the RF semiconductor die 110 is attached to the exposed substrate 1102, and then material 104a is provided to form the first layer 104.

[0060] In addition, such as Figure 11D As shown, a second layer 106 is formed on top of a first layer 104. Forming the second layer 106 includes forming a metal structure 108 and providing a dielectric material 130 for the second metal layer 106. A first segment 1104 of the metal structure 108 within the second layer 106 forms a waveguide antenna 114. The first segment 1104 of the metal structure 108 may be partially formed before and after the dielectric material 130 for the second metal layer 106. Therefore, the formed waveguide antenna 114 is filled with the dielectric material 130.

[0061] The metal structure 108 can be formed by laminating one or more metal layers. Other techniques may use electroplating molding or deposition of one or more metal layers. The entire surface of the first metal layer 104 facing the front side 118 of the RF semiconductor die 110 can be provided with a first portion 1104a of the first segment 1104 of the metal structure 108, such as a metal layer, and then the first portion 1104a of the first segment 1104 of the metal structure 108 can be selectively etched. The dielectric material 130 of the second layer 106 can be provided on the first layer 104, for example by deposition or electroplating. The dielectric material 130 surrounds the first portion 1104a of the first segment 1104 of the metal structure 108. The entire outermost surface of the second layer 106 facing the front side 118 of the RF semiconductor die 110 can be provided with a second portion 1104b of the first segment 1104 of the metal structure 108, such as another metal layer, and then the second portion 1104b of the first segment 1104 of the metal structure 108 can be selectively etched. The first section 1104 of the metal structure 108 also includes a vertical through hole 1104c, which connects portions 1104a and 1104b of the first section 1104 of the metal structure 108. This through hole can be formed before the dielectric material 130 is provided.

[0062] Selective etching of the first portion 1104a of the first segment 1104 of the metal structure 108 includes forming an inner opening 126. Similarly, selective etching of the second portion 1104b of the first segment 1104 of the metal structure 108 includes forming an outer opening 128.

[0063] According to one example, an air-filled waveguide antenna can be formed by selectively removing the dielectric material 130 of the second layer 106. In one example, the dielectric material 130 is selectively removed before forming the second portion 1104b of the first segment 1104 of the metal structure 108. For example, the dielectric material 130 between two vertical through-holes 1104c can be removed to form an air-filled waveguide antenna. In one example, the outer opening 128 of the air-filled waveguide antenna can be covered by another material forming the third layer 402, such as... Figure 4As shown. In one example, the third layer within the outer opening 128 can be selectively etched to expose the outer opening 128.

[0064] Figures 12A-12C The illustration shows a further step 1200 of method 1100. This additional step 1200 involves forming transmitters 202 and 502. Figure 12A As shown, holes 1202 and 1204 are formed to expose RF contact pads 206 from the material 104a of the first layer 104. The pitch of the RF contact pads 206 can be less than 120 μm, for example, 100 μm, measured between the centers of two adjacent RF contact pads 206 in a direction parallel to the front side 118 of the RF semiconductor die 110. The depth of holes 1202 and 1204 is the same as the thickness of the material 104a of the first layer 104 above the front side 118 of the semiconductor chip 110. Holes 1202 and 1204 can be formed by laser drilling, mechanical drilling, or by selective etching of the material 104a of the first layer 104. Figure 12B As shown, emitters 202 and 502 from the metal structure 108 are formed on the front side 118 of the RF semiconductor die 110, wherein vias 202a and 1208 are formed, for example, by electroplating in the corresponding holes 1202 and 1204. One end of the vias 202a and 1208 is coupled to the RF contact pad 206. The diameter of the vias is less than 50 μm, for example, 30 μm, which is measured in a direction parallel to the front side 118 of the RF semiconductor die 110.

[0065] Furthermore, second portions 202b and 1212 of the metal structure 108 are formed on the corresponding other ends of the through holes 202a and 1208. For example... Figure 12C As shown, the second portions 202b and 1212, together with the corresponding vias 202a and 1208, form emitters 202 and 502. The width of emitters 202 and 502 can be less than 100 μm, for example, 70 μm. The width of emitters 202 and 502 is the width of the second portions 202a and 1208 of the metal structure 108, which is measured in a direction parallel to the front side 118 of the RF semiconductor die 110. For a 100 μm pitch between the RF contact pads 206 and a 30 μm width for emitters 202 and 502, the distance between emitters 202 and 502 can be 30 μm. Therefore, for a given width of the RF semiconductor die, the emitter density can be increased. Emitter density refers to the number of emitters per unit area of ​​the RF semiconductor die.

[0066] Figures 13A-13B The illustration shows a further step 1300 of method 1100, which includes forming a separation via 504 in the waveguide antenna 114. Figure 12AHoles 1202 and 1204 are the first hole 1202 and the second hole 1204, respectively. Furthermore, Figure 12B Through holes 202a and 1208 are the first through hole 202a and the second through hole 1208, respectively. The metal structure portion 1212 is the third portion 1212 of the metal structure 108. Emitters 202 and 502 are the first emitter 202 and the second emitter 502, respectively. (As...) Figure 13A As shown, after forming emitters 202 and 502, a first hole 1308 can be formed in the second layer 106 of substrate 104 in a direction perpendicular to the front side 118 of RF semiconductor die 110. One end of the first hole 1308 can be located between the first emitter 202 and the second emitter 502. Figure 13B As shown, the via 504 can be formed, for example, by electroplating in the first hole 1308 of the second layer 106 of the substrate 102. The first hole 1308 can extend into the first layer 104 and expose the ground contact pad 506 of the RF semiconductor die 110. The via 504 can be mechanically coupled to the ground contact pad 506 of the RF semiconductor die 110.

[0067] In some examples, a contact structure from the metal structure 108 may be formed on the ground contact pad 506 before the second layer 106 is formed. This contact structure may be exposed from the first layer 104. A first via 1308 in the second layer 106 exposes this contact structure and a separating via 504 is coupled to the contact structure.

[0068] A separating via 504 separates the two portions 114a and 114b of the waveguide antenna 114 from each other. The first portion 114a and the second portion 114b of the waveguide antenna 114 are coupled to the first transmitter 202 and the second transmitter 502, respectively. The first transmitter 202 and the second transmitter 502 are coupled to the first channel and the second channel of the RF semiconductor die 110, respectively.

[0069] Figure 14 It shows Figure 11B Another alternative step 1401 for attaching the bare RF semiconductor die 110 is as follows: Instead of attaching the bare RF semiconductor die 110, a molded RF semiconductor die 610 may be attached to the surface 1106 of the substrate layer 1102. The molded RF semiconductor die 610 has a molded body 602 surrounding the RF semiconductor die 110. Thereafter, the same process steps as in the example of the bare RF semiconductor die 110 described above can be applied.

[0070] As described above, this application discloses a novel concept for an RF semiconductor device having a multilayered substrate and metal structure. As described herein, a waveguide antenna is formed by embedding an RF semiconductor die within and from the substrate, which is used to route RF signals and electrical signals. This RF device provides flexible methods for forming the transmitter; for example, the transmitter can be made from the metal structure of the substrate, or the RF semiconductor can include the transmitter. The substrate may have a protective layer to protect the RF semiconductor die from moisture and dust. Furthermore, interference with the RF signal within the waveguide antenna can be reduced by using vias. Additionally, the metal structure may have a heat sink for heat dissipation. The waveguide antenna can be used to transmit signals between different RF semiconductor dies to synchronize these RF semiconductor dies.

[0071] Figure 15 Another example of an RF device 1500 is shown. The RF device 1500 has a substrate 1502, a bare RF semiconductor die 1510, and a waveguide antenna 1514. The bare RF semiconductor die 1510 is embedded within the substrate 1502, while the waveguide antenna 1514 is mounted on the substrate 1502. The bare RF semiconductor die 1510 can be coupled with… Figure 1 Similar to the RF semiconductor die 110 in the original, the bare RF semiconductor die 1510 can also have an integrated transmitter or integrated antenna 1522 to wirelessly transmit or receive radio frequency signals. The substrate 1502 can be a printed circuit board. The substrate 1502 has a first layer 1504 and a metal structure 1508. The bare RF semiconductor die 1510 is disposed within the substrate 1510 such that the front side 1518 of the bare RF semiconductor die 1510 faces the first surface 1512 of the substrate 1502. Furthermore, the bare RF semiconductor die 1510 is surrounded by the material 1504a of the first layer 1504 of the substrate 1502. The first layer 1504 and... Figure 1 The first layer 104 of the substrate 102 is similar. The thickness of the material 1504a of the first layer 1504 between the front side 1518 and the first surface 1512 of the substrate 1502 can be less than 50 μm. Therefore, RF signals can be transmitted and received by the bare RF semiconductor die 1510 without significant loss.

[0072] Metal structure 1508 extends in a direction parallel to the first surface 1512 of substrate 1502 and in another direction perpendicular to the first surface 1512 of substrate 1502. An inner portion of metal structure 1508 extends within the first layer 1504, while an outer portion of metal structure 1508 extends outside the first layer 1504 of substrate 102. The outer portion of metal structure 1508 may extend on the first surface 1512 and the opposing second surface 1520 of substrate 102. The coupling of bare RF semiconductor die 1510 to metal structure 1508 is similar to... Figure 1The RF semiconductor die 110 of the RF device 100.

[0073] Furthermore, the RF device 1500 has a waveguide antenna 1514 mounted on a first surface 1512 of the substrate 1502 for transmitting RF signals from the bare RF semiconductor die 1510 to the outside of the RF device 1510, or from the outside of the RF device 1500 to the bare RF semiconductor die 1510. The waveguide antenna 1514 can be directly fixed to the first surface 1512 of the substrate 1502 by screws or glue. Figure 15 As shown, waveguide antenna 1514 is mounted on the outer portion of metal structure 1508 extending on the first surface 1512 of substrate 1502. The portion of waveguide antenna 1514 may be hollow, allowing RF signals to pass through. The hollow portion of waveguide antenna 1514 has an inner opening 1526 and an outer opening 1528. The inner opening 1526 faces the integrated antenna or integrated transmitter 1522 of the bare RF semiconductor die 1510 and couples RF signals between waveguide antenna 1514 and the bare RF semiconductor die 1510. On the other hand, the outer opening 1528 couples RF signals between waveguide antenna 1514 and the exterior of RF device 1500. Waveguide antenna 1514 may be made of metal, such as, but not limited to, copper, aluminum, or alloys thereof. Alternatively, waveguide antenna 1514 may be made of plastic, but the walls of its hollow portion are coated with metal, such as copper, aluminum, or alloys thereof.

[0074] By embedding the bare RF semiconductor die 1510 within the substrate 1502, the overall footprint of the RF device 1500 can be reduced compared to conventional RF devices (where the RF semiconductor die is molded before being mounted on the substrate). Therefore, for a given substrate 1502 size, the RF device 1500 can have more channels than conventional RF devices. By mounting the waveguide antenna 1514 directly on the substrate 1502, the signal path between the bare RF semiconductor die 1510 and the waveguide antenna 1514 can be shortened, thereby reducing transmission loss. Since the RF signal is transmitted directly between the bare RF semiconductor die 1510 and the waveguide antenna 1514, without the need for any microstrip lines and solder ball arrays, the transmission of the RF signal to the waveguide antenna 1514 can be more uniform and reliable. Overall, production costs can also be reduced because the packaging of the bare RF semiconductor die and its connection to the substrate (such as a printed circuit board) are integrated into a single manufacturing process.

[0075] In one example, the metal structure 1508 may further include a portion that forms a heat sink between the bare RF semiconductor die 1510 and the second surface 1520 of the substrate 1502 opposite to the first surface 1512, similar to... Figure 8The RF device 800 shows a heat sink 802. An additional heater can be coupled to this heater to further enhance heat transfer from the bare RF semiconductor die 1510.

[0076] In another example, the RF device 1500 may also include components embedded within or similar to a substrate 1502. Figure 7 The RF device 700 is a semiconductor die arranged on a substrate 1502 as shown.

[0077] Figure 16 Another example of an RF device 1600 is shown. The RF device 1600 may include... Figure 15 The RF device 1500 described below contains some or all of the features, but will only describe the differences. RF signals can be coupled between the bare RF semiconductor die 1510 and the waveguide antenna 1514 via transmitters 1602 and 1604, rather than via a chip-integrated antenna or chip-integrated transmitter integrated in the RF semiconductor die 1510. Transmitters 1602 and 1604 are formed from a first segment of a metal structure 1508. Transmitters 1602 and 1604 are similar to... Figure 5 The RF device 500 includes transmitters 202 and 502.

[0078] In another example, transmitters 1602 and 1604 may be exposed from the material 1504a of the first layer 1504 of substrate 1502 to reduce losses due to the material of the first layer 1504 of substrate 1502.

[0079] Transmitter 1602 can be a first transmitter coupled to a first channel of a bare RF semiconductor die, and transmitter 1604 can be a second transmitter coupled to a second channel of a bare RF semiconductor die 1510 within a substrate 1502. The first channel and the second channel can be either a transmit channel or a receive channel. The first transmitter 1602 is coupled to a first portion 1514a of a waveguide antenna 1514, and the second transmitter 1604 is coupled to a second portion 1514b of the waveguide antenna 1514.

[0080] Individually or in combination, the metal structure 1508 also includes a separating via 1608 extending in a second direction perpendicular to the first surface 1512 of the substrate 1502. Furthermore, the separating via 1608 may be located between transmitters 1602 and 1604 and mechanically coupled to the ground contact pad 1610 of the RF semiconductor die 1510. The separating via 1608 separates the first portion 1514a of the waveguide antenna 1514 from the second portion 1514b of the waveguide antenna 1514. The separating via 1608 reflects RF signals, thereby preventing interference from the second portion 1514b to the RF signals in the first portion 1514a of the waveguide antenna 1514. Therefore, interference between RF signals transmitted by the respective transmitters 1602 and 1604 within the waveguide antenna 114 can be significantly reduced, and the RF channels can be separated.

[0081] Figure 17 Another example of an RF device 1700 is shown, which has more than one bare RF semiconductor die coupled to each other. The bare semiconductor RF chips can, for example, form a cascaded system. RF device 1700 may include... Figure 16 The RF device 1600 may have some or all of its features, and the following description will focus only on the differences. The RF device 1700 may have another bare RF semiconductor die 1710. The bare RF semiconductor die 1510 may be a primary bare RF semiconductor die 1510, while the other bare RF semiconductor die 1710 may be a secondary bare RF semiconductor die 1710. As described above, the primary bare RF semiconductor die 1510 includes transmitters 1602, 1604, wherein each transmitter 1602, 1604 is coupled to a corresponding RF channel of the primary bare RF semiconductor die 1510. The secondary bare RF semiconductor die 1710 is also surrounded by the material of the first layer 1504 and coupled to the metal structure 1508 and the waveguide antenna 1514 in a manner similar to that of the primary bare RF semiconductor die 1510.

[0082] Furthermore, the sub-bare RF semiconductor die 1710 includes a first transmitter 1702 and a second transmitter 1704, wherein each transmitter 1702, 1704 is coupled to a corresponding RF channel of the sub-bare RF semiconductor die 1710. The first transmitter 1502, 1702 of each bare RF semiconductor die 1510, 1710 is coupled to a first portion 1514a and another portion 1514c of the waveguide antenna 1514. For example... Figure 17As shown, portions 1514a and 1514c are separated by vias 1608 and 1710. The second transmitter 1604 of the primary bare RF die 1510 is coupled to the second transmitter 1704 of the secondary bare RF die 1710 via a transmission waveguide 1706 integrated in the waveguide antenna 1514. The transmission waveguide 1706 is configured to transmit a local oscillator (LO) signal from the primary bare RF die 1510 to the secondary bare RF die 1710 via transmitters 1604 and 1710, thereby achieving synchronization between the primary and secondary bare RF dies 1510. This allows the primary and secondary bare RF dies 1510 and 1710 to operate on a common LO signal generated by the local oscillator of the primary bare RF die 1510. This achieves synchronization of the operation of the primary bare RF semiconductor die 1510 and the secondary bare RF semiconductor die 1710 through the transmission waveguide 1706 of the waveguide antenna 1514.

[0083] In one example, the transmission waveguide is embedded within a second layer of substrate 1502. The second layer may be located directly beneath the first surface of substrate 1502. Waveguide antenna 1514 may be partially integrated within substrate 1502. Therefore, the area occupied by waveguide antenna 1514 on substrate 1502 can be reduced. The second layer and transmission waveguide can be similar to... Figure 9 The second layer 106 and transmission waveguide 906 of the RF device 900.

[0084] More examples:

[0085] Example 1: A radio frequency (RF) device includes: a substrate including a first layer, a second layer, and a metal structure; an RF semiconductor die embedded in the substrate and surrounded by a material of the first layer of the substrate, wherein the RF semiconductor die is coupled to the metal structure, wherein the metal structure extends in a first direction (D1) parallel to a first surface of the substrate and in a second direction (D2) perpendicular to the first surface of the substrate; and a waveguide antenna formed by the metal structure in the second layer of the substrate for transmitting RF signals from the RF semiconductor die to the outside of the RF device, or from the outside of the RF device to the RF semiconductor die.

[0086] Example 2: The RF device according to Example 1 further includes a transmitter within a substrate, wherein the transmitter is coupled to an RF semiconductor die, and wherein the transmitter is configured to couple an RF signal between the RF semiconductor die and a waveguide antenna.

[0087] Example 3: An RF device according to Example 2, wherein the RF semiconductor die includes a transmitter.

[0088] Example 4: An RF device according to Examples 1 to 3, wherein the substrate includes a third layer covering an opening of a waveguide antenna, wherein the opening of the waveguide antenna extends to a first surface of the substrate.

[0089] Example 5: RF devices according to Examples 1 to 4, wherein the waveguide antenna is an air-filled waveguide antenna or a dielectric-filled waveguide antenna.

[0090] Example 6: An RF device according to Examples 1 to 5, wherein the transmitter is a first transmitter coupled to a first channel of an RF semiconductor die, and the RF device further includes: a second transmitter within a substrate, the second transmitter being coupled to a second channel of the RF semiconductor die, wherein the metal structure further includes a through-hole in a second direction D2, and wherein the through-hole separates a first portion of a waveguide antenna from a second portion of a waveguide antenna, wherein the first portion and the second portion of the waveguide antenna are coupled to the first transmitter and the second transmitter, respectively.

[0091] Example 7: An RF device according to Examples 1 to 6, wherein the RF semiconductor die has a molding body surrounding the RF semiconductor die, and wherein the RF semiconductor die is at least partially exposed from the molding body.

[0092] Example 8: An RF device according to Example 7, wherein the molded body includes a transmitter.

[0093] Example 9: An RF device according to any one of Examples 1 to 8, wherein the RF semiconductor die includes a plurality of contact pads, wherein each contact pad has a pitch dimension (P) of less than 250 μm, and wherein each contact pad is coupled to a metallic structure of a substrate to provide an electrical signal to the contact pad.

[0094] Example 10: The RF device according to Examples 1 to 9 further includes another semiconductor chip embedded in or disposed on a substrate.

[0095] Example 11: An RF device according to Examples 1 to 10, wherein the metal structure further includes a heat sink located between the RF semiconductor die and a second surface of the substrate opposite to the first surface.

[0096] Example 12: An RF device according to Examples 1 to 11, wherein the RF semiconductor die is a first RF semiconductor die, and the RF device further includes: a second RF semiconductor die, embedded in a substrate and surrounded by a first layer of material of the substrate, wherein the second RF semiconductor die is coupled to a metal structure and a waveguide antenna, wherein the waveguide antenna includes a transmission waveguide configured to transmit RF signals between the first RF semiconductor die and the second RF semiconductor die.

[0097] Example 13: An RF device according to Examples 1 to 12, wherein the substrate is a printed circuit board.

[0098] Example 14: A method of forming a radio frequency (RF) device including an RF semiconductor die embedded in a substrate, the method comprising: providing a substrate layer; attaching a first side of the RF semiconductor die to a surface of the substrate layer; providing a material over the surface of the substrate layer to form a first layer of the substrate such that the RF semiconductor die is surrounded by the material; forming a second layer of the substrate over the first layer of the substrate, wherein forming the second layer includes forming a metal structure, and wherein a first segment of the metal structure forms a waveguide antenna.

[0099] Example 15: The method according to Example 14 further includes: forming a first aperture before forming a second layer of the substrate to expose a second side of the RF semiconductor die from the material of the first layer of the substrate, wherein the second side of the RF semiconductor die is opposite to its first side, wherein forming the metal structure includes: forming a first via in the first aperture of the first layer of the substrate, and forming a second segment of the metal structure coupled to the first via to form a first transmitter for coupling RF signals between the RF semiconductor die and the waveguide antenna.

[0100] Example 16: The method according to Example 15 further includes: forming a second aperture before forming a second layer of the substrate to expose a second side of the RF semiconductor die from the material of the first layer of the substrate, wherein forming the metal structure includes: forming a second via in the second aperture of the first layer of the substrate, and forming a third segment of the metal structure coupled to the second via to form a second transmitter, forming a first aperture in the second layer of the substrate along a first direction perpendicular to the first side of the RF semiconductor die, forming a third via in the first aperture of the second layer of the substrate, wherein the third via separates a first portion of the waveguide antenna from a second portion of the waveguide antenna, wherein the first portion and the second portion of the waveguide antenna are coupled to a first transmitter and a second transmitter, respectively, and wherein the first transmitter and the second transmitter are coupled to a first channel and a second channel of the RF semiconductor die, respectively.

[0101] Example 17: According to the method of Examples 14 to 16, forming the metal structure further includes: etching a second portion of a first segment of the metal structure to form an opening in the waveguide antenna, and wherein the second portion of the first segment of the metal structure extends above the outermost surface of the second layer.

[0102] Example 18: The method of Example 17 further includes: placing a third material over the opening of the waveguide antenna.

[0103] Example 19: The method according to Example 18 further includes: etching a first material to expose an opening in the waveguide antenna.

[0104] Example 20: According to the method of Examples 14 to 19, attaching an RF semiconductor die to the surface of a substrate layer includes: attaching an RF semiconductor die attachment having a molded body surrounding the RF semiconductor die.

[0105] Example 21: A radio frequency (RF) device includes: a substrate including a first layer and a metal structure; a bare RF semiconductor die embedded in the substrate, wherein the bare RF semiconductor die is surrounded by and in contact with a material of the first layer of the substrate, wherein the metal structure extends along a first direction parallel to a first surface of the substrate and a second direction perpendicular to the first surface of the substrate; and a waveguide antenna mounted on the first surface of the substrate for transmitting RF signals from the bare RF semiconductor die to the outside of the RF device via the metal structure, or transmitting RF signals from the outside of the RF device to the bare RF semiconductor die via the metal structure.

[0106] Example 22: An RF device according to Example 21, wherein the metal structure includes a first portion forming a transmitter for coupling RF signals between a bare RF semiconductor die and a waveguide antenna.

[0107] Example 23: An RF device according to either Example 21 or 22, wherein the transmitter is exposed from the material of the first layer of the substrate.

[0108] Example 24: An RF device according to Example 21, wherein the bare RF semiconductor die includes a transmitter for coupling RF signals between the bare RF semiconductor die and a waveguide antenna.

[0109] Example 25: An RF device according to any one of Examples 22 to 24, wherein the transmitter is a first transmitter coupled to a first channel of a bare RF semiconductor die, and the RF device further includes: a second transmitter within a substrate coupled to a second channel of the bare RF semiconductor die, wherein the metal structure further includes a through-hole in a second direction perpendicular to a first surface of the substrate, and wherein the through-hole separates a first portion of a waveguide antenna from a second portion of a waveguide antenna, wherein the first portion and the second portion of the waveguide antenna are coupled to the first transmitter and the second transmitter of the bare RF semiconductor die, respectively.

[0110] Example 26: An RF device according to any one of Examples 21 to 25, wherein the metal structure further includes a second portion forming a heat sink between the bare RF semiconductor die and a second surface of the substrate opposite to the first surface.

[0111] Example 27: An RF device according to any one of Examples 21 to 26 further includes another semiconductor die embedded in or disposed on a substrate.

[0112] Example 28: An RF device according to any one of Examples 21 to 27, wherein the bare RF semiconductor die is a first bare RF semiconductor die, and the RF device further includes: a second bare RF semiconductor die embedded in a substrate, wherein the second bare RF semiconductor die is surrounded by and in contact with a material of a first layer of the substrate, wherein the waveguide antenna includes a transmission waveguide configured to transmit RF signals between the first bare RF semiconductor die and the second bare RF semiconductor die.

[0113] Example 29: An RF device according to Example 28, wherein the transmission waveguide is embedded in the second layer of the substrate.

[0114] Example 30: An RF device according to any one of Examples 21 to 29, wherein the substrate is a printed circuit board.

[0115] Although specific examples have been illustrated and described herein, those skilled in the art will understand that various alternatives and / or equivalent embodiments can be used to replace the illustrated and described specific examples without departing from the scope of the invention. This application is intended to cover any adaptations or variations of the specific examples discussed herein. Therefore, the invention is intended to be limited only to the claims and their equivalents.

[0116] It should be noted that the methods and apparatuses, including their preferred embodiments, outlined in this document can be used alone or in combination with other methods and apparatuses disclosed in this document. Furthermore, features outlined in the context of the apparatus also apply to the corresponding methods, and vice versa. Moreover, various aspects of the methods and apparatuses outlined in this document can be combined arbitrarily. In particular, features in the claims can be combined with each other in any manner.

[0117] It should be noted that the specification and accompanying drawings only illustrate the principles of the proposed methods and systems. Those skilled in the art will be able to implement various arrangements, which, while not explicitly described or shown herein, embody the principles of the invention and are contained within its spirit and scope. Furthermore, all examples and embodiments outlined in this document are explicitly intended for illustrative purposes only to aid the reader in understanding the principles of the proposed methods and systems. Moreover, all statements herein that provide for the principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to cover their equivalents.

Claims

1. A radio frequency (RF) device, comprising: The substrate (102) includes a first layer (104), a second layer (106), and a metal structure (108). An RF semiconductor die (110) is embedded within the substrate (102) and surrounded by a material (104a) of the first layer (104) of the substrate (102), wherein the RF semiconductor die (110) is coupled to the metal structure (108). The metal structure (108) extends in a first direction (D1) parallel to the first surface (112) of the substrate (102) and in a second direction (D2) perpendicular to the first surface (112) of the substrate (102), and A waveguide antenna (114), formed of the metal structure (108) in the second layer (106) of the substrate (102), is used to transmit RF signals from the RF semiconductor die (110) to the outside of the RF device, or from the outside of the RF device to the RF semiconductor die (110).

2. The RF device of claim 1, further comprising a transmitter (202) within the substrate (102), wherein the transmitter (202) is coupled to the RF semiconductor die (110), and wherein the transmitter (202) is configured to couple an RF signal between the RF semiconductor die (110) and the waveguide antenna (114).

3. The RF device according to claim 2, wherein the RF semiconductor die (110) includes the transmitter (122).

4. The RF device according to any one of claims 1 to 3, wherein the substrate (102) includes a third layer (402) covering an opening (128) of the waveguide antenna (114), wherein the opening (128) of the waveguide antenna (114) extends to the first surface (112) of the substrate (102).

5. The RF device according to any one of claims 1 to 4, wherein the waveguide antenna (114) is an air-filled waveguide antenna or a dielectric-filled waveguide antenna.

6. The RF device according to any one of claims 1 to 5, wherein the transmitter (202) is a first transmitter (202) coupled to a first channel of the RF semiconductor die (110), and the RF device further comprises: The second emitter (502) is located within the substrate (102) and is coupled to the second channel of the RF semiconductor die (110). The metal structure (108) further includes a through hole (504) in the second direction (D2), and The through-hole (504) separates the first portion (114a) of the waveguide antenna (114) from the second portion (114b) of the waveguide antenna (114), wherein the first portion (114a) and the second portion (114b) of the waveguide antenna (114) are coupled to the first transmitter (202) and the second transmitter (502), respectively.

7. The RF device according to any one of claims 1 to 6, wherein the RF semiconductor die (110) has a molding body (602) surrounding the RF semiconductor die (110), and wherein the RF semiconductor die (110) is at least partially exposed from the molding body (602).

8. The RF device of claim 7, wherein the molded body (602) includes a transmitter (604).

9. The RF device according to any one of claims 1 to 8, wherein the RF semiconductor die (110) includes a plurality of contact pads (132), wherein each contact pad (132) has a pitch dimension (P) of less than 250 μm, and wherein each contact pad (132) is coupled to the metal structure (108) of the substrate (102) to provide an electrical signal to the contact pad (132).

10. The RF device according to any one of claims 1 to 9 further includes another semiconductor die (702) embedded in or disposed on the substrate (102).

11. The RF device according to any one of claims 1 to 10, wherein the metal structure (108) further includes a heat sink (802) between the RF semiconductor die (110) and a second surface (120) of the substrate opposite to the first surface (112).

12. The RF device according to any one of claims 1 to 11, wherein the RF semiconductor die (110) is a first RF semiconductor die (110), and the RF device further comprises: A second RF semiconductor die (910) is embedded within the substrate (102) and surrounded by the material (104a) of the first layer (104) of the substrate (102). The second RF semiconductor die (910) is coupled to the metal structure (108) and the waveguide antenna (114). The waveguide antenna (114) includes a transmission waveguide (906) configured to transmit the RF signal between the first RF semiconductor die (110) and the second RF semiconductor die (910).

13. The RF device according to any one of claims 1 to 12, wherein the substrate (102) is a printed circuit board.

14. A method of forming a radio frequency (RF) device, the RF device comprising an RF semiconductor die (110) embedded within a substrate (102), the method comprising: Provide a substrate layer (1102). The first side (116) of the RF semiconductor die (110) is attached to the surface (1106) of the substrate layer (1102). A material (104a) is provided on the surface (1106) of the substrate layer (1102) to form a first layer (104) of the substrate (102), such that the RF semiconductor die (110) is surrounded by the material (104a). A second layer (106) of the substrate (102) is formed on the first layer (104) of the substrate (102), wherein forming (1107) the second layer (106) includes forming a metal structure (108), and The first segment (1104) of the metal structure (108) forms a waveguide antenna (114).

15. The method of claim 14, further comprising: Before forming the second layer (106) of the substrate (102), a first hole (1202) is formed to expose the second side (118) of the RF semiconductor die (110) from the material (104a) of the first layer (104) of the substrate (102). Wherein, the second side (118) of the RF semiconductor die (110) is opposite to the first side (116) of the RF semiconductor die (110). The formation of the metal structure (108) includes: forming a first through hole (202a) in the first hole (1202) of the first layer (104) of the substrate (102), and forming a second segment (202b) of the metal structure (108) coupled to the first through hole (202a) to form a first transmitter (202) for coupling RF signals between the RF semiconductor die (110) and the waveguide antenna (114).

16. The method of claim 15, further comprising: Before forming the second layer (106) of the substrate (102), a second hole (1204) is formed to expose the second side (118) of the RF semiconductor die (110) from the material (104a) of the first layer (104) of the substrate (102). The formation of the metal structure (108) includes: forming a second through hole (1208) in the second hole (1204) of the first layer (104) of the substrate (102), and forming a third segment (1212) of the metal structure (108) coupled to the second through hole (1208) to form a second emitter (502). A first hole (1308) is formed in the second layer (106) of the substrate (102) along a first direction perpendicular to the first side (116) of the RF semiconductor die (110). A third through-hole (504) is formed in the first hole (1308) of the second layer (106) of the substrate (102). The third through-hole (504) separates the first part (114a) of the waveguide antenna (114) from the second part (114b) of the waveguide antenna (114). The first portion (114a) and the second portion (114b) of the waveguide antenna (114) are coupled to the first transmitter (202) and the second transmitter (502) respectively, and The first transmitter (202) and the second transmitter (502) are coupled to the first channel and the second channel of the RF semiconductor die (110), respectively.

17. The method according to any one of claims 14 to 16, wherein, Forming the metal structure (108) further includes etching a second portion (1104b) of the first segment (1104) of the metal structure (108) to form an opening (128) in the waveguide antenna (114), wherein the second portion (1104b) of the first segment (1104) of the metal structure (108) extends over the outermost surface (1404) of the second layer (106).

18. The method of claim 17, further comprising: Another material (402) is arranged above the opening (128) of the waveguide antenna (114).

19. The method of claim 18, further comprising: The other material is etched to expose the opening (128) of the waveguide antenna (114).

20. The method according to any one of claims 14 to 19, wherein, Attaching the RF semiconductor die (110) to the surface (1106) of the substrate layer (1102) includes attaching the RF semiconductor die (110) having a molded body (602) surrounding the RF semiconductor die (110).

Images