Classifications

• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
  • H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
  • H03H9/46—Filters
  • H03H9/64—Filters using surface acoustic waves
  • H03H9/6406—Filters characterised by a particular frequency characteristic
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
  • H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
  • H03H9/02—Details
  • H03H9/05—Holders or supports
  • H03H9/10—Mounting in enclosures
  • H03H9/1064—Mounting in enclosures for surface acoustic wave [SAW] devices
  • H03H9/1092—Mounting in enclosures for surface acoustic wave [SAW] devices the enclosure being defined by a cover cap mounted on an element forming part of the surface acoustic wave [SAW] device on the side of the IDT's
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
  • H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
  • H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
  • H03H3/08—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of resonators or networks using surface acoustic waves
  • H03H3/10—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of resonators or networks using surface acoustic waves for obtaining desired frequency or temperature coefficient
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
  • H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
  • H03H9/02—Details
  • H03H9/02535—Details of surface acoustic wave devices
  • H03H9/02818—Means for compensation or elimination of undesirable effects
  • H03H9/02834—Means for compensation or elimination of undesirable effects of temperature influence
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
  • H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
  • H03H9/02—Details
  • H03H9/05—Holders or supports
  • H03H9/058—Holders or supports for surface acoustic wave devices
  • H03H9/059—Holders or supports for surface acoustic wave devices consisting of mounting pads or bumps
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
  • H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
  • H03H9/02—Details
  • H03H9/05—Holders or supports
  • H03H9/10—Mounting in enclosures
  • H03H9/1064—Mounting in enclosures for surface acoustic wave [SAW] devices
  • H03H9/1071—Mounting in enclosures for surface acoustic wave [SAW] devices the enclosure being defined by a frame built on a substrate and a cap, the frame having no mechanical contact with the SAW device

Definitions

• the field of the disclosure relates to surface acoustic wave (SAW) filters, and more particularly to SAW filter packages,
• SAW filter removes or reduces the energy in one or more bands of frequencies from an input analog signal.
• a SAW filter filters frequencies by transforming electromagnetic wave propagation into mechanical wave propagation on the surface of a substrate material.
• SAW filters can be implemented in die-sized SAW packages (DSSPs) for use in a mobile device, as an example.
• DSSPs die-sized SAW packages
• the SAW filter package includes a functional substrate (“substrate”) that comprises a piezoelectric material and has a first surface with a first and second interdigital transducer ( IDT) disposed therein to provide a SAW filter circuit.
• substrate functional substrate
• IDT interdigital transducer
• the SAW filter package also includes a cavity frame comprising a frame perimeter structure and a cavity inside the frame perimeter structure coupled to the substrate.
• a cap substrate is disposed on the frame perimeter structure of the cavity frame to enclose an air cavity inside the frame perimeter structure between the substrate and the cap substrate.
• the cavity frame is comprised of a material that has an enhanced thermally conductivity.
• the cavity frame may be comprised of a diamond material to provide a diamond cavity frame.
• the cavity frame may be comprised of a material that has a thermal conductivity of at least five (5) Watts (W) per meter (m)-Kelvin (W/m-K). In this manner, heat generated in the SAW filter package can more effectively be dissipated, particularly at edges and comers of the cavity frame where hot spots can particularly occur.
• the side walls of the cavity frame are aligned or co-planar to the side walls of the cap substrate in a vertical direction, as opposed to the side walls of the cavity frame extending further outward from the side walls of the cap substrate forming a shoulder area or staggered frame edge.
• the area of the SAW filter is reduced in the horizontal direction to reduce the area of the SAW filter package, which may be desired if the SAW filter package is employed in devices with reduced available area for circuit packages.
• Aligning the side walls of the cavity frame and cap substrate can also reduce metal interconnect path lengths between metal interconnects (e.g., solder bumps) on the cap substrate and metal interconnects on the substrate.
• the cavity frame is patterned and formed on the cap substrate as opposed to the substrate. This allows the cavity frame patterned on the cap substrate to be diced in a vertical direction in a dicing step such that their respective side walls are co-planar in the vertical direction. This can avoid or reduce misalignment between the cap substrate and cavity frame that may otherwise occur if the cavity frame is formed on the substrate, wherein the cap substrate must then be aligned and coupled to the cavity frame that has a greater width to provide an alignment tolerance to the cap substrate, further, forming the cavity frame on the cap substrate may also be advantageous if the thermal budget for deposition of the cavity frame material exceeds the thermal budget of the substrate.
• the cap substrate may be formed from a material that does not include metallization structures and thus can tolerate the increased thermal budget for the cavity frame material deposition.
• a SAW filter package in one exemplary aspect, includes a substrate including a piezoelectric material and having a first surface.
• the SAW filter package also includes a cap substrate.
• the SAW filter package also includes a diamond cavity frame disposed between the substrate and the cap substrate that forms a cavity between the cap substrate and the first surface of the substrate.
• the SAW filter package also includes a first IDT on the first surface of the substrate inside the cavity.
• the SAW filter package also includes a second IDT on the first surface of the substrate inside the cavity.
• a SAW filter package in another exemplary' aspect, includes a substrate including a piezoelectric material and having a first surface.
• the SAW filter package also includes a cap substrate.
• the SAW filter package also includes a cavity frame having a thermal conductivity of at least five (5) Watts (W) per meter (m)-Kelvin (W/m-K).
• the cavity frame is disposed between the substrate and the cap substrate that forms a cavity between the cap substrate and the first surface of the substrate.
• the SAW filter package also includes a first IDT on the first surface of the substrate inside the cavity.
• the SAW filter package also includes a second IDT on the first surface of the substrate inside the cavity.
• a method of fabricating a SAW filter package includes providing a cap substrate comprising a first surface.
• the method also includes coupling a first surface of a cavity frame to the cap substrate.
• the cavity frame has a thermal conductivity of at least 5 W/m-K.
• the method also includes providing a substrate including a piezoelectric material, a first surface, a first IDT on the first surface of the substrate, and a second IDT on the first surface of the substrate.
• the method also includes coupling a second surface of the cavity frame to the first surface of the substrate thereby forming a cavity between the cap substrate and the first surface of the substrate and enclosing the first IDT and the second IDT.
• Figure 1A is a cross-sectional side view of an exemplary circuit package that includes a surface acoustic wave (SAW) filter package employing an enhanced thermally conductive cavity frame for heat dissipation and a co-planar cap substrate and cavity frame for die size reduction and shorter metal interconnect paths;
• SAW surface acoustic wave
• Figure 1B is a perspective side view of the SAW filter package in the circuit package in Figure 1 A employing an enhanced thermally conductive cavity frame for heat dissipation and a co-planar cap substrate and cavity frame for die size reduction and shorter metal interconnect paths;
• Figure 2A is a cross-sectional side view of the SAW filter package in Figures 1 A and IB employing an enhanced thermally conductive cavity frame for heat dissipation and a co-planar cap substrate and cavity frame for die size reduction and shorter metal interconnect paths:
• Figure 2B is a perspective side view of the SAW filter package in Figure 2A illustrating the frame perimeter structure of the cavity frame;
• Figure 2C is a close-up, cross-sectional side view of a section of the SAW filter package in Figure 2A illustrating the co-planarity of the cap substrate and cavity frame:
• Figure 3 is a cross-sectional side view of a SAW filter package that does not include an enhanced thermally conductive cavity frame for heat dissipation and a co- planar cap substrate and cavity frame for die size reduction and shorter metal interconnect paths;
• Figure 4 is a flowchart illustrating an exemplary process of fabricating a SAW filter package employing an enhanced thermally conductive cavity frame for heat dissipation with a co-planar cap substrate and cavity frame, including, but not limited to, the SAW filter package in Figures 1 A-2C;
• Figures 5A-5C are a flowchart illustrating another exemplary process for fabricating an enhanced thermally conductive cavity frame co-planar with a cap substrate for a SAW filter package for heat dissipation, including, but not limited to, the cavity frame and cap substrate in the SAW filter package in Figures 1A-2C;
• Figures 6A-6I illustrate exemplary fabrication stages during fabrication of an enhanced thermally conductive cavity frame co-planar with a cap substrate for a SAW filter package for heat dissipation, including, but not limited to, the cavity frame and cap substrate in the SAW filter package in Figures 1A-2C, according to the exemplary fabrication process in Figures 5A-5C:
• Figure 7 is a flowchart illustrating an exemplary process for fabricating a substrate for a SAW filter package, including, but not limited to, the substrate in the SAW filter package in Figures 1A-2C;
• Figures 8A and 8B illustrate exemplary fabrication stages during fabrication of a substrate for a SAW filter package, including, but not limited to, the substrate in the SAW filter package in Figures 1 A-2C, according to the exemplary fabrication process in Figure 7;
• Figure 9 is a flowchart illustrating an exemplary process for assembling an enhanced thermally conductive cavity frame co-planar with a cap substrate, coupled to a substrate to create a SAW filter package, including, but not limited to, the SAW filter package in Figures 1 A-2C;
• Figures 10A and 10B illustrate exemplary fabrication stages during assembly of an enhanced thermally conductive cavity frame co-planar with a cap substrate, coupled to a substrate to create a SAW filter package, including, but not limited to, the SAW filter package in Figures 1A-2C, according to the exemplary fabrication process in Figure 9;
• Figure 11 is a cross-sectional side view of an exemplary circuit package that includes a SAW filter employing an enhanced thermally conductive cavity frame for heat dissipation;
• Figure 12A is a perspective side view of the SAW filter package in the circuit package in Figure 11 employing an enhanced thermally conductive cavity frame for heat dissipation;
• Figure 12B is a cross-sectional side view of the SAW filter package in Figure 11 employing an enhanced thermally conductive cavity frame for heat dissipation;
• Figure 13 is a block diagram of an exemplary processor-based system that can include components that can include a SAW filter package employing an enhanced thermally conductive cavity frame for heat dissipation and/or a co-planar cap substrate and cavity frame for die size reduction and shorter metal interconnect paths, including, but not limited, to the SAW filter packages in Figures 1A-2C and 11-12B, and according to the exemplary fabrication processes in Figures 4-10B; and
• FIG 14 is a block diagram of an exemplary wireless communications device that includes radio-frequency (RF) components that can include a SAW filter package employing an enhanced thermally conductive cavity frame for heat dissipation and/or a co-planar cap substrate and cavity frame for die size reduction and shorter metal interconnect paths, including, but not limited to, the SAW filter packages in Figures 1 A- 2C and 11-12B, and according to the exemplary fabrication processes in Figures 4-10B.
• RF radio-frequency
• the SAW filter package includes a functional substrate (“substrate”) that comprises a piezoelectric material and has a first surface with a first and second interdigital transducer (IDT) disposed therein to provide a SAW filter circuit.
• substrate functional substrate
• IDT interdigital transducer
• the SAW filter package also includes a cavity frame comprising a frame perimeter structure and a cavity inside the frame perimeter structure coupled to the substrate.
• a cap substrate is disposed on the frame perimeter structure of the cavity frame to enclose an air cavity inside the frame perimeter structure between the substrate and the cap substrate.
• the cavity frame is comprised of a material that has an enhanced thermally conductivity.
• the cavity frame may be comprised of a diamond material to provide a diamond cavity frame.
• the cavity frame may be comprised of a material that has a thermal conductivity of at least five (5) Watts (W) per meter (m)-Kelvin (W/m-K). In this manner, heat generated in the SAW filter package can more effectively be dissipated, particularly at edges and comers of the cavity frame where hot spots can particularly occur.
• the side walls of the cavity frame are aligned or co-planar to the side walls of the cap substrate in a vertical direction, as opposed to the side walls of the cavity frame extending further outward from the side walls of the cap substrate forming a shoulder area or staggered frame edge.
• the area of the SAW filter is reduced in the horizontal direction to reduce the area of the SAW filter package, which may be desired if the SAW filter package is employed in devices with reduced available area for circuit packages.
• Aligning the side walls of the cavity frame and cap substrate can also reduce metal interconnect path lengths between metal interconnects (e.g., solder bumps) on the cap substrate and metal interconnects on the substrate.
• the cavity frame is patterned and formed on the cap substrate as opposed to the substrate. This allows the cavity frame patterned on the cap substrate to be diced in a vertical direction in a dicing step such that their respective side walls are co-planar in the vertical direction. This can avoid or reduce misalignment between the cap substrate and cavity frame that may otherwise occur if the cavity frame is formed on the substrate, wherein the cap substrate must then be aligned and coupled to the cavity frame that has a greater width to provide an alignment tolerance to the cap substrate. Further, forming the cavity frame on the cap substrate may also be advantageous if the thermal budget for deposition of the cavity frame material exceeds the thermal budget of the substrate.
• the cap substrate may be formed from a material that does not include metallization structures and thus can tolerate the increased thermal budget for the cavity frame material deposition.
• Figure 1A is a cross-sectional side view of an exemplar ⁇ ' circuit package 100 that includes a SAW filter package 102 that provides a SAW filter circuit 103.
• the SAW filter package in Figure 1 A is shown along a cross-section line Ai-Ai’ in Figure IB.
• the SAW filter package 102 is each configured to block certain frequency ranges of an input radio-frequency (RF) signal.
• the circuit package 100 may be included in another integrated circuit (IC) package that includes RF transmission/reception circuity and antennas where the SAW filter package 102 is employed to filter transmitted and/or received RF signals.
• the SAW filter package 102 includes a substrate 104 that is made from a piezoelectric material 106 in this example.
• a first interdigital transducer (IDT) 108(1) is disposed on a first surface 110 of the substrate 104 as an input circuit.
• a second IDT 108(2) is also disposed on the first surface 110 of the substrate 104 adjacent to the first IDT 108(1) as an output circuit.
• the first IDT 108(1) is configured to receive a R.F signal through a first metal interconnect 112(1) coupled to a first metal conductor 114(1).
• the first metal conductor 114(1) is coupled through the metal interconnect 122(2) (e.g., solder bumps, solder balls) on the cap substrate 126, to metal interconnects 124 (e.g., metal lines, metal traces, vertical interconnect accesses (vias)) in metallization layers 116(1), 116(2) in a package substrate 118 to a signal source.
• the first IDT 108(1) is configured to convert the received electrical RF signal into an acoustic wave that is emitted in a cavity 120 formed between the substrate 104 and the cap substrate 126.
• the cavity 120 is an air cavity.
• the second IDT 108(2) is configured to receive a filtered acoustic wave of the emitted acoustic wave emitted by the first IDT 108(1) and convert filtered acoustic wave into a filtered RF signal.
• the filtered RF signal is coupled to a second metal interconnect 112(2) coupled to a second metal conductor 114(2).
• the second metal conductor 114(2) is coupled through a metal interconnect 122(2) (e.g., solder bumps, solder balls) on the cap substrate 126, to the metal interconnects 124 in the metallization layers 116(1), 116(2) in the package substrate 118 to another circuit to receive the filtered RF signal.
• the cap substrate 126 is disposed on a cavity frame 128 that is disposed on the substrate 104.
• the cavity frame 128 provides a stand-off between the cap substrate 126 and the substrate 104.
• the cap substrate 126 is a substrate of material that is used to form the cavity 120.
• the cap substrate 126 is disposed on the frame perimeter structure of the cavity frame 128 to enclose the cavity 120 inside the frame perimeter structure between the substrate 104 and the cap substrate 126.
• Heat is generated inside the cavity 120 as a result of the operation of the SAW filter circuit 103. Excessive heat that is not effectively dissipated can increase the temperature of the SAW filter circuit 103 and negatively affect its filtering performance.
• the cavity frame 128 is comprised of a material that has an enhanced thermal conductivity, as opposed to for example, a polymer material that is not a good thermal conductor.
• the cavity frame 128 may be comprised of a diamond material to provide a diamond cavity frame.
• the cavity frame 128 may be compri sed of a material that has a thermal conductivity of at least five (5) Watts (W) per meter (m)-Kelvin (W/m-K).
• a diamond cavity frame may have a thermal conductivity between and including 600 - 2,000 W/m-K. In this manner, heat generated in the SAW filter package 102 can more effectively be dissipated, particularly at edges and comers of the cavity frame 128 where hot spots can particularly occur.
• the SAW filter package 102 employs the cap substrate 126 that has side walls 130 that are co-planar with side walls 132 of the cavity frame 128 in a vertical direction in the Z-axis direction. This is also shown in the perspective side view of the SAW filter package 102 in Figure IB. This is opposed to the side walls 130 of the cap substrate 126 being staggered in the horizontal direction in the Y-axis direction with the side walls 132 of the cavity frame 128. This can facilitate die size reduction of the SA W filter package 102 in the X-axis direction and also shorter metal interconnect paths of the metal conductors 114(1), 114(2).
• Aligning the respective side walls 132, 130 of the cavity frame 128 and the cap substrate 126 can also reduce metal conductor 114(1), 114(2) path lengths between respective metal interconnects 112(1), 112(2) on the substrate 104 and the respective metal interconnects 122(1), 122(2) on the cap substrate 126 and metal interconnects 112(1), 112(2) on the substrate 104.
• the cavity frame 128 can be patterned and formed on the cap substrate 126 first in a fabrication process of the SAW filter package 102, as shown in Figure 1B. This is opposed to the cavity frame 128 being first formed on the substrate 104.
• the cavity frame 128 patterned on the cap substrate 126 can be diced in a vertical direction (Z- axis direction) in a dicing step such that the respective side walls 130, 132 of the cap substrate 126 and cavity frame 128 are co-planar in the vertical direction.
• This can avoid or reduce misalignment between the cap substrate 126 and cavity frame 128 that may otherwise occur if the cavity frame 128 is first formed on the substrate 104.
• the latter scenario may require the cavity frame 128 to have a greater width in the horizontal direction (X-axis direction) to support providing an alignment tolerance between the cavity frame 128 and the cap substrate 126.
• forming the cavity frame 128 in the horizontal direction (X-axis direction) on the cap substrate 126 may also be advantageous if the thermal budget for deposition of the material of the cavity frame 128 exceeds the thermal budget of the substrate 104.
• the heat generated by deposition of the cavity frame 128 may be diffused by the metal interconnects 124 in the metallization layers 116(1), 116(2) of the substrate 104 and could adversely affect performance of the circuit package 100.
• the cap substrate 126 may be formed from a material that does not include metallization structures and thus can tolerate the increased thermal budget of the material deposition of the cavity frame 128.
• Figures 2A and 213 are provided.
• Figure 2 A is cross-sectional side view of the SAW filter package 102 in Figures 1 A and IB.
• Figure 2B is a perspective side view of the SAW filter package in Figure 2A illustrating the frame perimeter structure of the cavity frame 128.
• the first and second IDTs 108(1), 108(2) are disposed on the first surface 110 of the substrate 104.
• the cavity frame 128 is disposed between the cap substrate 126 and the first surface 110 of the substrate 104.
• the cavity frame 128 includes a frame perimeter structure 200 that has an internal cavity 202 inside the frame perimeter structure 200.
• the internal cavity 202 will create the cavity 120 of the SAW filter package 102 as a result of the cavity frame 128 being disposed between the substate 104 and the cap substate 126.
• the cavity frame 128 can have a thermal conductivity of at least five (5) W/m-K to be more effective in dissipating heat generated in the SAW filter package 102. This is opposed to providing the cavity frame 128 of a polymer material that may have a thermal conductivity between 0.1 - 0.5 W/m-K.
• the cavity frame 128 may be a diamond cavity frame made from a diamond material that has a thermal conductivity between and including 600 - 2,000 W/m-K.
• Providing the cavity frame 128 as a diamond cavity frame may also allow the material of the cap substrate 126 to be provided of a less expensive material, such as Silicon, because as discussed below, the cavity frame 128 is formed on the cap substrate 126 in an exemplary fabrication process.
• the frame perimeter structure 200 includes a first perimeter surface 204(1) that is disposed on or adjacent to the first surface 110 of the substrate 104.
• Other examples of materials that can be used to form the cavity frame 128 and that have an enhanced thermal conductivity include aluminum oxide, silicon nitride, and/or sapphire, as non-limiting examples.
• the frame perimeter structure 200 also has a second perimeter surface 204(2) that is on the opposite side of the first perimeter surface 204(1) in a vertical axis direction (Z-axis direction).
• the second perimeter surface 204(2) of the frame perimeter structure 200 is disposed on or adjacent to a second surface 205 of the cap substrate 126.
• Metal interconnects 208(1), 208(2) are disposed on or adjacent to a first surface 210 of the cap substrate 126 to support the coupling of the metal interconnects 122(1), 122(2) to the metal conductors 114(1), 114(2).
• the first perimeter surface 204(1) of the frame perimeter structure 200 of the cavity frame 128 may be disposed on a pad 213 that is disposed on the first surface 110 of the substrate 104, to facilitate bonding of the material of the cavity frame 128 to the substrate 104.
• the pad 213 may be an Aluminum pad that supports the bonding of a diamond cavity frame 128 to the substrate 104.
• the frame perimeter structure 200 of the cavity frame 128 comprises a rectangular-shaped frame perimeter structure that includes four side structures 206(l)-206(4) disposed at right angles to each other.
• the four side structures 206(1 )-204(4) of the frame perimeter structure 200 define an outer perimeter with a cavity 207 formed inside the frame perimeter structure 200.
• the second perimeter surface 204(2) of the frame perimeter structure 200 is formed by the bottom surfaces of the side structures 206(l)-206(4) in Figure 2B.
• the second perimeter surface 204(2) of the frame perimeter structure 200 is formed by the top surfaces of the side structures 206(l)-206(4).
• the cavity frame 128 may be provided that has a coefficient of thermal expansion (CTE) less than or equal to ten (10) parts per million (ppm) per degree Celsius (C) (ppm/deg C). In this manner, the cavity frame 128 is less susceptive to expansion and contraction in response to temperature changes that may occur due to heat generated during operation of the SAW filter circuit 103.
• a cavity frame 128 made from a diamond material may have a CTE less than or equal to one (1) ppm/deg C.
• the cavity frame 128 may be provided of a material that has an electrical resistivity greater than or equal to 1 x 10 10 Ohms centimeter (cm) (Ohms cm).
• a cavity frame 128 made from a diamond material may have an electrical resistivity between and including 1 x 10 14 and 1 x 10 18 Ohms cm.
• Figure 2C is a close-up, cross-sectional side view of a section of the SAW filter package 102 in Figure 2 A illustrating the co-planarity of the side walls 130, 132 of the respective cap substrate 126 and cavity frame 128.
• the side walls 130 of the cap substrate 126 and the side walls 132 of the cavity frame 128 are co-planar or substantially co-planar with each other along plane P 1 .
• the side walls 130 of the cap substrate 126 and the respective side walls 132 extend out in the horizontal direction (X-axis direction) to the same point or approximately the same point.
• the side walls 130 of the cap substrate 126 and the side walls 132 of the cavity frame 128 extend along respective longitudinal axes L 1 , L 2 that are parallel to each other to the same or substantially the same point in the horizontal direction or Y -axis of plane P 1 in the Y-X axes.
• Figure 2C only shows a left side of the SAW filter package 102 in Figures 2A and 2B, the same features are also provided on the other sides of the SAW filter package 102.
• planar or substantially co-planar side walls 130 of the cap substrate 126 and side walls 132 of the cavity frame 128 allows the metal conductor 114(1) to extend along the outside of the side walls 130 of the cap substrate 126 and the side walls 132 of the cavity frame 128 in the vertical or Z-axis direction without creating a jog or shoulder area that would be present if the side walls 130 of the cap substrate 126 and the side walls 132 of the cavity frame 128 were staggered in their extension in the horizontal direction.
• This can reduce the length of the metal conductors 114(1), 114(2) to decrease resistivity of the couplings between the IDTs 108(1), 108(2) and the respective metal conductors 114(1), 114(2) for improved performance.
• This is opposed to, for example, the SAW filter package 302 shown in the cross-sectional diagram in Figure 3.
• side walls 330 of a cap substrate 326 are staggered with side walls 332 of a cavity frame 328.
• Common elements between the SAW filter package 302 in Figure 3 and the SAW filter package 102 in Figures 1-2C are shown with common element numbers.
• the side walls 330 of the cap substrate 326 extend in a horizontal direction (X-axis direction) to plane P 2 in the Y-X axes.
• the side walls 332 of the cavity frame 328 extend in a horizontal direction (X-axis direction) to plane P 3 in the Y-X axes that extends further away from the cavity 320 than the side walls 330.
• the staggered cap substrate 326 and cavity frame 328 can also have the effect of extending the width of the SAW filter package 302 in the horizontal direction (X-axis direction) over the SAW filter package 102 in Figures 1A-2C.
• the staggering of the cap substrate 326 to the cavity frame 328 in this example can be a result of forming the cavity frame 328 on the substrate 104 first before the cap substrate 326 is disposed on the cavity frame 328. Disposing the cap substrate 326 on the substrate 104 may require the width of the cavity frame 328 to need to be expanded to provide a sufficient landing tolerance for the cap substrate 326.
• FIG 4 is a flowchart illustrating an exemplary process 400 of fabricating a SAW filter package employing an enhanced thermally conductive cavity frame for heat dissipation with a co-planar cap substrate and cavity frame, including, but not limited to, the SAW filter package 102 in Figures 1 A-2C.
• the process 400 in Figure 4 is discussed with reference to the exemplary SAW filter package 102 in Figures 1A-2C.
• a fabrication step in the fabrication process 400 of fabricating the SAW filter package 102 in Figures 1A-2C can include providing a cap substrate 126 comprising a first surface 205 (block 402 in Figure 4).
• a next step of the fabrication process 400 can include coupling a first perimeter surface 204(1) of a cavity frame 128 comprising a cavity 207 to the cap structure 126 (block 404 in Figure 4).
• the cavity frame 128 may have a thermal conductivity of at least five (5) W/m-K to provide enhanced thermal conductivity to dissipate heat generated in the SAW filter package 102.
• the cavity frame 128 may be made from a highly thermally conductive material such as diamond, aluminum oxide, silicon nitride, and/or sapphire as non-limiting examples.
• a next step of the fabrication process 400 can include providing a substrate 104 comprising a piezoelectric material 106, a first surface 110, a first IDT 108(1) on the first surface 110 of the substrate 104, and a second IDT 108(2) on the first surface 110 of the substrate 104 (block 406 in Figure 4).
• a next step of the fabrication process 400 can include coupling a second perimeter surface 204(2) of the cavity frame 128 to the first surface 110 of the substrate 104 thereby forming a cavity 120 between the cap substrate 126 and the first surface 110 of the substrate 104 and enclosing the first IDT 108(1) and the second IDT 108(2) (block 408 in Figure 4).
• FIGS. 5A-5C are a flowchart illustrating an exemplary fabrication process 500 for fabricating an enhanced thermally conductive cavity frame co-planar with a cap substrate to be used in a S AW filter package, including, but not limited to, the cavity frame 128 and cap substrate 126 in the SAW filter package 102 in Figures 1A-2C.
• the cavity frame 128 on the cap substrate 126 may be desired to form the cavity frame 128 on the cap substrate 126 before coupling these package components on the substrate 104 as a convenient method to achieve co-planarity between the side walls 130, 132 of the cap substrate 126 and cavity frame 128.
• This can avoid or reduce misalignment between the cap substrate 126 and cavity frame 128 that may otherwise occur if the cavity frame 128 is formed on the substrate 104, wherein the cap substrate 126 must then be aligned and coupled to the cavity frame 128 that has a staggered width to provide an alignment tolerance to the cap substrate 126.
• forming the cavity frame 128 on the cap substrate 126 may also be advantageous if the thermal budget for deposition of the cavity frame 128 material exceeds the thermal budget of the substrate 104. This can avoid diffusion of the metal interconnects in the metallization layers 116(1 ) ⁇ 116(2) of the substrate 104 that could adversely affect performance of the SAW filter package 102.
• the cap substrate 126 may be formed from a material that does not include metallization structures and thus can tolerate the increased thermal budget for the cavity frame 128 material deposition.
• Figures 6A-6I illustrate exemplary fabrication stages 600A-600I during fabrication of an enhanced thermally conductive cavity frame co-planar with a cap substrate for a SAW filter package for heat dissipation, including, but not limited to, the cavity frame 128 and cap substrate 126 in the SAW filter package 102 in Figures 1A-2C, according to the exemplary fabrication process 500 in Figures 5A-5C.
• the fabrication process 500 and exemplary fabrication stages 600A-600I in Figures 6A-6I will be discussed with reference to the SAW filter package 102 example in Figures 1A-2C.
• a step in the fabrication process 500 of the cavity frame 128 disposed on the cap substrate 126 is to provide the cap substrate 126 (block 502 in Figure 5A).
• the cap substrate 126 may a Silicon material.
• next step in the fabrication process 500 can then include depositing an etch material layer 602 comprising an etch material 604 on a first surface 606 of the cap substrate 126 (block 504 in Figure 5 A).
• the etch material 604 may be Silicon Dioxide.
• the etch material layer 602 is disposed on the cap substrate 126 as a material that can be patterned with openings for a cavity frame material to be disposed in the openings to form the cavity frame 128 on the cap substrate 126. This is shown in the fabrication stage 600C in Figure 6C. As shown therein, a next step in the fabrication process 500 is to pattern the etch material layer 602 to form perimeter openings 608(1), 608(2) in the etch material 604 (block 506 in Figure 5A). The fabrication stage 600C in Figure 6C illustrates two (2) perimeter openings 608(1), 608(2), however it should be note that the fabrication stage 600C in Figure 6C is shown as a cross-section and that perimeter openings 608 are formed in the etch material layer 602 in a closed pattern.
• a next step in the fabrication process 500 can be to dispose a cavity frame material 610 that will be used to form the cavity frame 128 in the perimeter openings 608(1), 608(2) (block 508 in Figure 5B).
• a next step in the fabrication process 500 can be to grind down and/or polish a top surface 612 of the cavity frame material 610 to form the second perimeter surface 204(2) of the cavity frame 128 (block 510 in Figure 5B).
• a next step in the fabrication process 500 can be to remove (e.g., etch away) the etch material 604 remaining in the etch material layer 602 to leave the cavity frame 128 formed on the cap substrate 126 (block 512 in Figure 5B).
• the fabrication process 500 may involve forming several adjacent cavity frames 128 on the cap substrate 126 that can later be diced as discussed below to form individual packages.
• a next step in the fabrication process 500 can be to backgrind the cap substrate 126 to form the first surface 210 of the cap substrate 126 (block 514 in Figure 5D).
• a cavity frame 128 with its side structures 206(l)-206(4) formed from the cavity frame material 610 is formed on the cap substrate 126 (block 516 in Figure 5C).
• this process may form a plurality of cavity frames 128 formed on the cap substrate 126.
• the side structures 206(1)-206(4) can be diced through the cap substrate 126 in the vertical direction (Z-axis direction) to form coplanar side walls 130, 132 between the cap substrate 126 and the cavity frame 128 as previously discussed (block 518 in Figure 61).
• a laser may be employed to dice through the cap substrate 126 in the vertical direction (Z-axis direction) to form coplanar side walls 130, 132 between the cap substrate 126 and the cavity frame 128.
• Figure 7 is a flowchart illustrating an exemplary process 700 for fabricating a substrate for a SAW filter package, including, but not limited to, the substrate 104 in the SAW filter package 102 in Figures 1A-2C.
• Figures 8A and 8B illustrate exemplary fabrication stages 800A, 800B during fabrication of the substrate for the SAW filter package, including, but not limited to, the substrate 104 in the SAW filter package 102 in Figures 1A-2C, according to the exemplary fabrication process 700 in Figure 7.
• the fabrication process 700 and exemplary fabrication stages 800A, 800B in Figures 8A and 8B will be discussed with reference to the SAW filter package 102 example in Figures 1A-2C.
• a substrate 104 is provided (block 702 in Figure 7).
• the substrate 104 may be a Lithium Niobate (LiNbO 3 ) substrate.
• a metal layer 802 of a metal material 804 is disposed on the first surface 110 of the substrate 104 to form the IDTs 108(1), 108(2) and their metal interconnects 112(1), 112(2) (block 704 in Figure 7).
• the metal material 804 may be Aluminum as an example.
• the SAW filter package 102 can be assembled by taking the combination cavity frame 128 formed on the cap substrate 126 according to the exemplary fabrication process 500 and exemplary fabrication stages 600A-600I in Figures 5A-6I and coupling same to the substrate 104 fabricated according to the exemplary fabrication process 700 and exemplary' fabrication stages 800A, 800B in Figures 8A and 8B. This then forms the cavity 120 between the substate 104 and cap substrate 126 by the cavity frame 128 disposed therebetween,
• the cavity frame 128 formed on the cap substrate 126 is coupled to the substrate 104 such that the cavity 120 is formed with the IDTs 108(1), 108(2) disposed inside the cavity 120 (block 902 in Figure 9).
• the metal interconnects 112(1), 112(1) may be provided as an Aluminum material for example, to facilitate bonding of the cavity frame 128 as a diamond cavity frame as an example.
• the bonding of the cavity frame 128 formed on the cap substrate 126, to the substrate 104 may be performed at lower temperatures, including at room temperature, without exceeding the thermal budget of the substrate 104, and thus impacting the substrate 104, because the higher temperatures that may be needed to form the cavity frame 128 are done on the cap substrate 126 and not on the substrate 104 in this example.
• the metal conductors 114(1), 114(2) can be formed on the metal interconnects 112(1), 112(2) and adjacent to the side walls 130, 132 and on the first surface 210 of the cap substrate 126 to form interconnects between the IDTs 108(1), 108(2) and the metal interconnects 122(1), 122(2) (e.g., solder bumps, solder balls) coupled to the metal conductors 114(1), 114(2) (block 904 in Figure 9).
• the metal conductors 114(1), 114(2) may be formed by a Titanium deposition on a Copper seed layer, for example, and patterned as Copper Nickel traces.
• the metal interconnects 122(1), 122(2) can be formed on patterned interconnects as solder bumps or balls (e.g., SnAugCu solder balls).
• a SAW filter package can also be provided like the SAW filter package 102 in Figures 1-2C and 5A-10B that includes a cavity frame of an enhanced thermally conductive material to facilitate heat dissipation, but the cavity frame can be formed on the substrate instead of the cap substrate.
• the cavity frame and cap substate may include a staggered configuration where their respective side walls do not extend to the same point out from the air cavity to be co-planar.
• SAW filter package 102 is illustrated in Figures 11-12B.
• Figure 11 a cross-sectional side view of an exemplary circuit package 1100 that includes a SAW filter package 1102 that provides a SAW filter circuit 1103.
• the SAW filter package 1102 is configured to block certain frequency ranges of an input R.F signal.
• the circuit package 1100 may be included in another IC package that includes RF transmission/reception circuity and antennas where the SAW filter package 1102 is employed to filter transmitted and/or received RF signals.
• the SAW filter package 1102 includes a substrate 1104 that is made from a piezoelectric material 1106 in this example.
• a first IDT 1108(1) is disposed on a first surface 1110 of the substrate 1104 as an input circuit.
• a second IDT 1108(2) is also disposed on the first surface 1110 of the substrate 1104 adjacent to the first IDT 1108(1) as an output circuit.
• the first IDT 1108(1) is configured to receive a RF signal through a first metal interconnect 1112(1) coupled to a first metal conductor 1114(1).
• the first metal conductor 1114(1) is coupled through a metal interconnect 1122(2) (e.g., solder bumps, solder balls) on a cap substrate 1126, to metal interconnects 1124 (e.g., metal lines, metal traces, vias) in metallization layers 1116(1), 1116(2) in a package substrate 1118 to a signal source.
• the first IDT 1108(1) is configured to convert, the received electrical RF signal into an acoustic wave that is emitted in a cavity 1120, which may be an air cavity.
• the second IDT 1108(2) is configured to receive a filtered acoustic wave of the emitted acoustic wave emitted by the first IDT 1108(1) and convert filtered acoustic wave into a filtered RF signal.
• the filtered RF signal is coupled to a second metal interconnect 1112(2) coupled to a second metal conductor 1114(2).
• the second metal conductor 1114(2) is coupled through the metal interconnect 1122(2) (e.g., solder bumps, solder balls) on the cap substrate 1126, to metal interconnects 1124 in metallization layers 1116(1), 1116(2) in the package substrate 1118 to another circuit to receive the filtered RF signal.
• metal interconnect 1122(2) e.g., solder bumps, solder balls
• the cap substrate 1126 is disposed on a cavity frame 1128 that is disposed on the substrate 1104.
• the cavity frame 1128 provides a stand-off between the cap substrate 1126 and the substrate 1104.
• the cap substrate 1126 is a substrate of material that is used to form the cavity 1120.
• the cap substrate 1126 is disposed on a frame perimeter structure of the cavity frame 1128 to enclose the cavity 1120 inside the frame perimeter structure between the substrate 1104 and the cap substrate 1126.
• Heat is generated inside the cavity 1120 as a result of the operation of the SAW filter circuit 1103. Excessive heat that is not effectively dissipated can increase the temperature of the SAW filter circuit 1103 and negatively affect its filtering performance.
• the ca vity frame 1128 is comprised of a material that has an enhanced thermally conductivity, as opposed to for example, a. polymer material that is not a good thermal conductor.
• the cavity frame 1128 may be comprised of a diamond material to provide a diamond cavity frame.
• the cavity frame 1128 may be comprised of a material that has a thermal conductivity of at least five (5) W/m-K.
• a diamond cavity frame may have a thermal conductivity between and including 600 - 2,000 W/m-K. In this manner, heat generated in the SAW filter package 1 102 can more effectively be dissipated, particularly at edges and comers of the cavity frame 1128 where hot spots can particularly occur,
• Figure 12A illustrates another cross-sectional side view of the SAW filter package 1102 in Figure 11.
• the first and second IDTs 1108(1), 1108(2) of the SAW filter package 1102 are disposed on the first surface 1110 of the substrate 1104.
• the cavity frame 1128 is disposed between the cap substrate 1126 and the first surface 1110 of the substrate 1104.
• the cavity frame 1128 includes a frame perimeter structure 1200 that has an internal cavity 1202 inside the frame perimeter structure 1200.
• the internal cavity 1202 will create the cavity 1120 of the SAW filter package 1102 as a result of the cavity frame 1128 being disposed between the substate 1014 and the cap substate 1126.
• the cavity frame 1128 can have a thermal conductivity of at least five (5) W/m-K to be more effective in dissipating heat generated in the SAW filter package 1102. This is opposed to providing the cavity frame 1128 of a polymer material that may have a thermal conductivity between 0.1 - 0.5 W/m-K.
• the cavity frame 1128 may be a diamond cavity frame made from a diamond material that has a thermal conductivity between and including 600 - 2,000 W/m-K.
• Providing the cavity frame 1128 as a diamond cavity frame may also allow the material of the cap substrate 1126 to be provided of a less expensive material, such as Silicon, because as discussed below, the cavity frame 1128 is formed on the cap substrate 1126 in an exemplary fabrication process.
• Diamond material can be disposed (e.g., through a deposition or sputtering process) and bonded to Silicon.
• the frame perimeter structure 1200 includes a first perimeter surface 1204(1) that is disposed on or adj acent to the first surface 1110 of the substrate 1104.
• materials that can be used to form the cavity frame 1128 and that have an enhanced thermal conductivity include aluminum oxide, silicon nitride, and/or sapphire, as non-limiting examples.
• the frame perimeter structure 1200 also has a second perimeter surface 1204(2) that is on the opposite side of the first perimeter surface 1204(1) in a vertical axis direction (Z-axis direction).
• the second perimeter surface 1204(2) of the frame perimeter structure 1200 is disposed on or adjacent to a second surface 1205 of the cap substrate 1126.
• Metal interconnects 1208(1), 1208(2) are disposed on or adjacent to a first surface 1210 of the cap substrate 1126 to support the coupling of the metal interconnects 1122(1), 1122(2) to the metal conductors 1114(1), 1114(2).
• the first perimeter surface 1204(1) of the frame perimeter structure 1200 of the cavity frame 1128 may be disposed on a pad 1213 that is disposed on the first surface 1110 of the substrate 1104, to facilitate bonding of the material of the cavity frame 1128 to the substrate 1104,
• the pad 1213 may be an Aluminum pad that supports the bonding of a diamond cavity frame 1128 to the substrate 1104.
• the frame perimeter structure 1200 of the cavity frame 1128 comprises a rectangular-shaped frame perimeter structure that includes four side structures 1206(1)- 1206(4) disposed at right angles to each other.
• the four side structures 1206(1)- 1204(4) of the frame perimeter structure 1200 define an outer perimeter with a cavity 1207 formed inside the frame perimeter structure 1200.
• the first perimeter surface 1204(1) of the frame perimeter structure 1200 is formed by the bottom surfaces of the side structures 1206(1)- 1206(4) in Figure 1213.
• the second perimeter surface 1204(2) of the frame perimeter structure 1200 is formed by the top surfaces of the side structures 1206(l)-206(4).
• the cavity frame 1128 may be provided that has a CTE less than or equal to ten ( 10) ppm/deg C. In this manner, the cavity frame 1 128 is less susceptive to expansion and contraction in response to temperature changes that may occur due to heat generated during operation of the S AW filter circuit 1103.
• a cavity frame 1128 made from a diamond material may have a CTE less than or equal to one (1) ppm/deg C.
• the cavity frame 1128 may be provided of a material that has an electrical resistivity greater than or equal to 1 x 10 10 Ohms cm.
• a cavity frame 1128 made from a diamond material may have an electrical resistivity between and including 1 x 10 14 and 1 x 10 18 Ohms cm.
• side walls 1130 of the cap substrate 1126 are staggered with side walls 1132 of the cavity frame 1128.
• the side walls 1130 of the cap substrate 1126 extend in a horizontal direction (X-axis direction) to plane P4 in the Y-X axes.
• the side walls 1132 of the cavity frame 1128 extend in a horizontal direction (X-axis direction) to plane P 5 in the Y-X axes that extends further away from the cavity 1120 than the side walls 1130. This creates a shoulder area 1234 between the side walls 1130, 1132 that extends the path length of the metal conductors 1114(1), 1114(2).
• a SAW filter package employing an enhanced thermally conductive cavity frame for heat dissipation and/or a co-planar cap substrate and cavity frame for die size reduction and shorter metal interconnect paths may be provided in or integrated into any processor-based device.
• GPS
• Figure 13 illustrates an example of a processor-based system 1300.
• the components of the processor-based system 1300 are ICs 1302.
• Some or all of the ICs 1302 in the processor-based system 1300 can be provided in a SAW filter package 1304 employing an enhanced thermally conductive cavity frame for heat dissipation and/or a co-planar cap substrate and cavity frame for die size reduction and shorter metal interconnect paths, including, but not limited to, the exemplary SAW filter packages in Figures 1-2B and 11- 12B and according to the exemplary fabrication processes in Figures 4-1 OB, and according to any aspects disclosed herein.
• the processorbased system 1300 may be formed as a SAW filter package 1304 and as a system-on-a- chip (SoC) 1306.
• the processor-based system 1300 includes a CPU 1308 that includes one or more processors 1310, which may also be referred to as CPU cores or processor cores.
• the CPU 1308 may have cache memory 1312 coupled to the CPU 1308 for rapid access to temporarily stored data.
• the CPU 1308 is coupled to a system bus 1314 and can intercouple master and slave devices included in the processor-based system 1300.
• the CPU 1308 communicates with these other devices by exchanging address, control, and data information over the system bus 1314.
• the CPU 1308 can communicate bus transaction requests to a memory controller 1316 as an example of a slave device.
• multiple system buses 1314 could be provided, wherein each system bus 1314 constitutes a different fabric.
• Other master and slave devices can be connected to the system bus 1314. As illustrated in Figure 13, these devices can include a memory system 1320 that includes the memory controller 1316 and a memory array(s) 1318, one or more input devices 1322, one or more output devices 1324, one or more network interface devices 1326, and one or more display controllers 1328, as examples. Each of the memory system 1320, the one or more input devices 1322, the one or more output devices 1324, the one or more network interface devices 1326, and the one or more display controllers 1328 can be provided in the same or different circuit packages.
• the input device(s) 1322 can include any type of input device, including, but not limited to, input keys, switches, voice processors, etc.
• the output device(s) 1324 can include any type of output device, including, but not limited to, audio, video, other visual indicators, etc.
• the network interface device(s) 1326 can be any device configured to allow exchange of data to and from a network 1330.
• the network 1330 can be any type of network, including, but not limited to, a wired or wireless network, a private or public network, a local area network (LAN), a wireless local area network (WLAN), a wide area network (WAN), a BLUETOOTHTM network, and the Internet.
• the network interface device(s) 1326 can be configured to support any type of communications protocol desired.
• the CPU 1308 may also be configured to access the display controllers) 1328 over the system bus 1314 to control information sent to one or more displays 1332.
• the display controllers) 1328 sends information to the display(s) 1332 to be displayed via one or more video processors 1334, which process the information to be displayed into a format suitable for the display(s) 1332.
• the display controllers) 1328 and video processor(s) 1334 can be included as SAW filter package 1304 and the same or different circuit packages, and in the same or different circuit packages containing the CPU 1308 as an example.
• the display(s) 1332 can include any type of display, including, but not limited to, a cathode ray tube (CRT), a liquid crystal display (LCD), a plasma display, a light emitting diode (LED) display, etc.
• FIG 14 illustrates an exemplary wireless communications device 1400 that includes radio frequency (RF) components formed from one or more ICs 1402, wherein any of the ICs 1402 can include a SAW filter package(s) 1403 employing an enhanced thermally conductive cavity frame for heat dissipation and/or a co-planar cap substrate and cavity frame for die size reduction and shorter metal interconnect paths, including but not limited to, the exemplary SAW filter packages in Figures 1-2B and 11-12B and according to the exemplary fabrication processes in Figures 4-10B, and according to any aspects disclosed herein.
• the wireless communications device 1400 may include or be provided in any of the above-referenced devices, as examples.
• the wireless communications device 1400 includes a transceiver 1404 and a data processor 1406.
• the data processor 1406 may include a memory to store data and program codes.
• the transceiver 1404 includes a transmitter 1408 and a receiver 1410 that support bi-directional communications.
• the wireless communications device 1400 may include any number of transmitters 1408 and/or receivers 1410 for any number of communication systems and frequency bands. All or a portion of the transceiver 1404 may be implemented on one or more analog ICs, RFICs, mixed-signal ICs, etc.
• the transmitter 1408 or the receiver 1410 may be implemented with a superheterodyne architecture or a direct-conversion architecture.
• a signal is frequency-converted between RF and baseband in multiple stages, e.g., from RF to an intermediate frequency (IF) in one stage, and then from IF to baseband in another stage for the receiver 1410.
• IF intermediate frequency
• the direct-conversion architecture a signal is frequency-converted between RF and baseband in one stage.
• the super-heterodyne and direct-conversion architectures may use different circuit blocks and/or have different requirements.
• the transmitter 1408 and the receiver 1410 are implemented with the direct-conversion architecture.
• the data processor 1406 processes data to be transmitted and provides I and Q analog output signals to the transmitter 1408.
• the data processor 1406 includes digital-to-analog converters (DACs) 1412(1), 1412(2) for converting digital signals generated by the data processor 1406 into the I and Q analog output signals, e.g., I and Q output currents, for further processing.
• DACs digital-to-analog converters
• lowpass filters 1414(1), 1414(2) filter the I and Q analog output signals, respectively, to remove undesired signals caused by the prior digital-to-analog conversion.
• Amplifiers (AMPs) 1416(1), 1416(2) amplify the signals from the lowpass filters 1414(1), 1414(2), respectively, and provide I and Q baseband signals.
• An upconverier 1418 upcon verts the I and Q baseband signals with I and Q transmit (TX) local oscillator (LO) signals through mixers 1420(1), 1420(2) from a TX LO signal generator 1422 to provide an upconverted signal 1424.
• TX transmit
• LO local oscillator
• a filter 1426 filters the upconverted signal 1424 to remove undesired signals caused by the frequency upconversion as well as noise in a receive frequency band.
• a power amplifier (PA) 1428 amplifies the upconverted signal 1424 from the filter 1426 to obtain the desired output power level and provides a transmit RF signal.
• the transmit RF signal is routed through a duplexer or switch 1430 and transmitted via an antenna 1432.
• the antenna 1432 receives signals transmitted by base stations and provides a received RF signal, which is routed through the duplexer or switch 1430 and provided to a low noise amplifier (LNA) 1434.
• LNA low noise amplifier
• the duplexer or switch 1430 is designed to operate with a specific receive (RX)-to-TX duplexer frequency separation, such that RX signals are isolated from TX signals.
• the received RF signal is amplified by the LNA 1434 and filtered by a filter 1436 to obtain a desired RF input signal.
• Downconversion mixers 1438(1), 1438(2) mix the output of the filter 1436 with I and Q RX LO signals (i.e., LO_I and LO_Q) from an RX LO signal generator 1440 to generate I and Q baseband signals.
• the I and Q baseband signals are amplified by AMPs 1442(1), 1442(2) and further filtered by lowpass filters 1444(1), 1444(2) to obtain I and Q analog input signals, which are provided to the data processor 1406.
• the data processor 1406 includes analog-to-digital converters (ADCs) 1446(1), 1446(2) for converting the analog input signals into digital signals to be further processed by the data processor 1406.
• ADCs analog-to-digital converters
• the TX LO signal generator 1422 generates the I and Q TX LO signals used for frequency upconversion, while the RX LO signal generator 1440 generates the 1 and Q RX LO signals used for frequency downconversion.
• Each LO signal is a periodic signal with a particular fundamental frequency.
• a TX phase-locked loop (PLL) circuit. 1448 receives timing information from the data processor 1406 and generates a control signal used to adjust the frequency and/or phase of the TX LO signals from the TX LO signal generator 1422.
• an RX PLL circuit 1450 receives timing information from the data processor 1406 and generates a control signal used to adjust the frequency and/or phase of the RX LO signals from the RX LO signal generator 1440.
• DSP Digital Signal Processor
• ASIC Application Specific Integrated Circuit
• FPGA Field Programmable Gate Array
• a processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine.
• a processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration).
• RAM Random Access Memory
• ROM Read Only Memory
• EPROM Electrically Programmable ROM
• EEPROM Electrically Erasable Programmable ROM
• registers a hard disk, a removable disk, a CD-ROM, or any other form of computer readable medium known in the art.
• An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium.
• the storage medium may be integral to the processor.
• the processor and the storage medium may reside in an ASIC.
• the ASIC may reside in a remote station.
• the processor and the storage medium may reside as discrete components in a remote station, base station, or server.
• a surface acoustic wave (SA W) filter package comprising: a substrate comprising a piezoelectric material and having a first surface; a cap substrate; and a diamond cavity frame disposed between the substrate and the cap substrate that forms a cavity between the cap substrate and the first surface of the substrate; a first interdigital transducer (IDT) on the first surface of the substrate inside the cavity; and a second IDT on the first surface of the substrate inside the cavity.
• SA W surface acoustic wave
• cap substrate comprises at least one cap substrate side wall that is co-planar in a vertical direction with at least one frame side wall of the diamond cavity frame,
• the cap substrate comprises a first cap substrate side wall that extends along a first longitudinal axis and a second cap substrate side wall that extends along a second longitudinal axis parallel to the first longitudinal axis;
• the diamond cavity frame comprises a first frame side wall that extends along the first longitudinal axis and a second frame side wall that extends along the second longitudinal axis; and the first cap substrate side wall is co-planar to the first frame side wall in a vertical direction, and the second cap substrate side wall is co-planar to the second frame side wall in the vertical direction.
• the cap substrate comprises a rectangular-shaped cap substrate frame perimeter structure
• the diamond cavity frame comprises a rectangular-shaped diamond frame perimeter structure
• the rectangular-shaped cap substrate frame perimeter structure is co-planar to the rectangular-shaped diamond frame perimeter structure.
• the SAW filter package of clause 2 further comprising a first metal interconnect coupled to a first surface of the cap substrate opposite a second surface of the cap substrate: a second metal interconnect coupled to the first surface of the cap substrate; a first metal conductor disposed on a first cap substrate side wall among the at least one cap substrate side wall and a first frame side wall among the at least one frame side wall and coupling the first metal interconnect to the first IDT: and a second metal conductor disposed on a second cap substrate side wall among the at least one cap substrate side wall and a second frame side wall among the at least one frame side wall and coupling the second metal interconnect to the second IDT.
• the cap substrate comprises a Silicon material.
• the diamond cavity frame comprises a diamond frame perimeter structure comprising a first perimeter surface coupled to the first surface of the substrate and a second perimeter surface; and the cap substrate comprises a second surface coupled to the second perimeter surface of the diamond frame perimeter structure and enclosing the cavity inside the diamond frame perimeter structure between the substrate and the cap substrate.
• GPS global positioning system
• a surface acoustic wave (SAW) filter package comprising: a substrate comprising a piezoelectric material and having a first surface; a cap substrate; a cavity frame having a thermal conductivity of at least five (5) Watts (W) per meter (m)-Kelvin (W/m-K), the cavity frame disposed between the substrate and the cap substrate that forms a cavity between the cap substrate and the first surface of the substrate; a first interdigital transducer (IDT) on the first surface of the substrate inside the cavity; and a second IDT on the first surface of the substrate inside the cavity.
• the cap substrate comprises at least one cap substrate side wall that is co-planar in a vertical direction with at least one frame side wall of the cavity frame.
• the cap substrate comprises a first cap substrate side wall that extends along a first longitudinal axis and a second cap substrate side wall that extends along a second longitudinal axis parallel to the first longitudinal axis;
• the cavity frame comprises a first frame side wall that, extends along the first longitudinal axis and a second frame side wall that extends along the second longitudinal axis; and the first cap substrate side wall is co-planar to the first frame side wall in a vertical direction, and the second cap substrate side wall is co-planar to the second frame side wall in the vertical direction.
• the cap substrate comprises a rectangular-shaped cap substrate frame perimeter structure
• the cavity frame comprises a rectangular-shaped frame perimeter structure
• the rectangular-shaped cap substrate frame perimeter structure is co-planar to the rectangular-shaped frame perimeter structure.
• the cavity frame comprises a material comprised from the group consisting of aluminum oxide, silicon nitride, and sapphire.
• the SAW filter package of clause 14 further comprising: a first metal interconnect coupled to a first surface of the cap substrate opposite a second surface of the cap substrate; a second metal interconnect coupled to the first surface of the cap substrate; a first metal conductor disposed on a first cap substrate side wall among the at least one cap substrate side wall and a first frame side wall among the at least one frame side wall and coupling the first metal interconnect to the first IDT; and a second metal conductor disposed on a second cap substrate side wall among the at least one cap substrate side wall and a second frame side wall among the at least one frame side wall and coupling the second metal interconnect to the second IDT.
• the SAW filter package of any of clauses 13-15 further comprising: an Aluminum pad disposed on the first surface of the substrate; and wherein: the cavity frame is coupled to the Aluminum pad to couple the cavity frame to the substrate.
• GPS global positioning system
• a method of fabricating a surface acoustic wave (SAW) filter package comprising: providing a cap substrate comprising a first surface: coupling a first surface of a cavity frame to the cap substrate, the cavity frame having a thermal conductivity of at least five (5) Watts (W) per meter (m) ⁇ Kelvin (W/m-K); providing a substrate comprising a piezoelectric material, a first surface, a first interdigital transducer (IDT) on the first surface of the substrate, and a second IDT on the first surface of the substrate; and coupling a second surface of the cavity frame to the first surface of the substrate thereby forming a cavity between the cap substrate and the first surface of the substrate and enclosing the first IDT and the second IDT.
• SAW surface acoustic wave

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