An inductor can store energy in a magnetic field when electric current flows through it, and can provide an electric current by discharging the stored energy. Inductor can have many applications, such as proximity sensing, energy storage, actuation, power transmission, and filtering. The inductor may be coupled to or can be part of an integrated circuit, which can include circuitries that operate with the inductor to support those applications. In some examples, the inductor and the circuitries can be enclosed in an integrated circuit package, which can reduce the footprint of the integrated circuit and shorten the interconnects between the inductor and the circuitries.
An integrated circuit comprises: a substrate, a semiconductor die, metal interconnects, and inductor, and a magnetic material. The semiconductor die is mounted to the substrate via the metal interconnects. The inductor is mounted to the substrate. The magnetic material encapsulates the semiconductor die, the inductor, and the metal interconnects, the magnetic material including: coated metal particles, which are coated with a first insulation material; and a second insulation material, in which the coated metal particles are suspended.
A method comprises: mounting semiconductor dies to a substrate, and mounting inductors to the substrate. The method further comprises depositing a magnetic material on the semiconductor dies and the inductors, the magnetic material including: coated metal particles, which are coated with a first insulation material; and a second insulation material, in which the coated metal particles are suspended. The method further comprises molding the magnetic material, and dicing the magnetic material and the substrate to form integrated circuits including respective semiconductor dies and inductors.
Semiconductor die 104 and inductor 102 can form a system to support a particular application, such as proximity sensing, energy storage, actuation, power transmission, and filtering. For example, integrated circuit 100 can include a proximity sensor, in which semiconductor die 104 can include an oscillator and a sensing circuit. The oscillator can drive inductor 102 with an oscillating current signal, and the sensing circuit can sense the frequency of the current signal. A metal object approaching inductor 102 can change the inductance of inductor 102, which can change the frequency of the current signal. The sensing circuit can detect the metal object by detecting the frequency change. As another example, integrated circuit 100 can include a switch-mode power converter to transmit power from a power source to a load. In such example, inductor 102 can provide energy storage, and semiconductor die 104 can include switches to charge and discharge the inductor 102 to set the voltage across the load.
Also, package substrate 106 can provide mechanical support to inductor 102 and semiconductor die 104, and provide electrical connections between the inductor and the semiconductor die, and electrical connections to between integrated circuit 100 and an external device. For example, package substrate 106 can include an electrical insulation material, such as a polymer, an Ajinomoto Build-up Film (ABF), or a ceramic material. Package substrate 106 can also include metal pads 110, 112, 114, 116, and 118, which can be Copper pads, on a surface 120 to which inductor 102 and semiconductor die 104 are mounted.
Also, semiconductor die 104 can include a passivation layer 122, which can be coupled to metal pads 110, 112, 114, and 116 via respective metal interconnects 130, 132, 134, and 136. Each pad can be coupled to a respective metal interconnect via a solder layer. Passivation layer 122 can insulate circuitries in semiconductor die 104 from metal interconnects 130, 132, 134, and 136. Metal interconnects 130 through 136 can include, for example, Copper pillars, solder bumps, and under bump metallization (UBM) interconnects. Also, inductor 102 can be coupled to metal pad 118 via a solder layer. Package substrate 106 can include metal interconnects on or under surface 120 to provide electrical connections between inductor 102 and semiconductor die 104, such as metal interconnect 140 between metal pads 116 and 118.
Package substrate 106 can also include metal pads on a surface 150 opposite to surface 120, such as metal pads 160, 162, and 164 which can include Copper pads or pads made of other metals (e.g., Silver or Palladium). Package substrate 106 can also include metal interconnects, such as Copper interconnects, to provide electrical connections between metal pads on the opposite surfaces. For example, package substrate 106 can include metal interconnect 170 between metal pads 110 and 160, metal interconnect 172 between metal pads 112 and 162, and metal interconnect 174 between metal pads 114 and 164. The metal pads on surface 150 and the interconnects can provide electrical connections between an external device and integrated circuit 100. For example, metal pads 160, 162, and 164 can be coupled to a printed circuit board (PCB) 176 via respective solder balls 180, 182, and 184, which can provide electrical connections between integrated circuit 100 and an external device (e.g., a power source) on PCB 176. Package substrate 106 can also include a solder resist layer 190 on surface 150 to shield metal interconnects in the package substrate (e.g., metal interconnects 170, 172, and 174) from the solder balls.
Package substrate 206 can include metal pads 220, 222, 224, 226, 228, and 230, which can be Copper pads, on a surface 232 on which inductor 202 and semiconductor die 104 are attached. Integrated circuit 200 can include metal interconnects 130, 132, 134, and 136 of semiconductor die 104 can be coupled to respective metal pads 222, 224, 226, and 228 via a solder layer. Also, stilts 212a and 212b of inductor 202 can be coupled to respective metal pads 220 and 230 via a solder layer.
Package substrate 206 can also include metal pads on a surface 250 opposite to surface 232, such as metal pads 252, 254, 256, and 258 which can include Copper pads or pads made of other metals (e.g., Silver and Palladium). Metal pads 252, 254, 256, and 258 can be coupled to an external device via solder balls, such as PCB 176 and solder balls 180 through 184 of
Also, as described above, inductor 202 and semiconductor die 104 can be encapsulated in encapsulation package 208 on package substrate 206. Encapsulation package 208 can include a magnetic material such as an MMC. The MMC can have metallic particles (e.g., iron particles) and an insulation material (e.g., a polymer resin) in which the metallic particles are suspended. Encapsulation package 208 can shield inductor 202 and increase the magnetic field density, which can improve the efficiency of inductor 202 in converting between electrical and magnetic energies. The MMC material of encapsulation package 208 can fill the space within inductor 202, such as in the center of coil portion 210 (e.g., if inductor 202 has an air core) and between individual coils of coil portion 210. The MMC material can also fill the space between coil portion 210 and semiconductor die 104, and between metal interconnects 130, 132, 134, and 136.
Package substrate 206 can include metal pad 234 (e.g., Copper pad) in addition to metal pads 220 through 230 on surface 232 on which semiconductor die 104 and capacitor 280 are attached. Integrated circuit 200 can include metal interconnects 130, 132, and 136 (e.g., Copper pillars, solder bumps, or UBM interconnects) coupled between semiconductor die 104 and respective metal pads 222, 224, and 226 of package substrate 206. Also, integrated circuit 200 can include metal interconnects 282 and 284 (e.g., Copper pillars, solder bumps, or UBM interconnects) coupled between capacitor 280 and respective metal pads 228 and 234. Package substrate 206 can also include metal interconnects coupled between metal pads on surface 232 and on surface 250 to provide external access to semiconductor die 104, inductor 202, and capacitor 280. For example, package substrate 206 can include metal interconnect 262 coupled between metal pads 222 and 252, metal interconnect 264 coupled between metal pads 224 and 254, metal interconnect 266 coupled between metal pads 228 and 256, and metal interconnect 268 coupled between metal pads 230 and 258. Package substrate 206 can also include metal interconnect 260 coupled among metal pads 220, 226, and 228 to provide an internal electrical connection among semiconductor die 104, inductor 202, and capacitor 280.
By placing semiconductor die 104 and/or capacitor 280 below coil portion 210 of inductor 202, integrated circuit 200 of
Integrated circuit 200 can be fabricated by mounting multiple electronic components (e.g., semiconductor dies 104, inductors 202 and/or capacitors 280) to a substrate, depositing an MMC material onto the electronic components and the substrate, molding and hardening the MMC material to form an encapsulation package, and then dicing the molded and hardened MMC material and the substrate into multiple integrated circuits 200, such that each integrated circuit 200 can include a set of electronic components (e.g., a semiconductor die 104, an inductor 202 and/or a capacitor 280) mounted to substrate 206 and encapsulated by MMC encapsulation package 208.
While the MMC encapsulation package can increase magnetic field density within integrated circuit 200, the dicing operation can change the structure of the MMC material on the diced surface and reduce the electrical breakdown voltage through the MMC material. Because of the reduced electrical breakdown voltage, a relatively small voltage difference between the metal interconnects can be sufficient for leakage current to flow between the metal interconnects through the MMC material, which can increase the risk of electrical shorts. Accordingly, the functionality, reliability, and safety of integrated circuit 200 can become compromised.
Referring to
However, the dicing operation may remove some of the resin on diced surfaces 502 and 504, which may expose the metal particles on the diced surfaces and reduce the resistance of the leakage current path through those metal particles. For example, metal particles 526 and 528 on diced surface 502 and metal particles 530 and 532 on diced surface 504 may be exposed by the removal of Epoxy resin 533. Accordingly, part of metal particles 526 and 528 can be separated by an air gap 550, and part of metal particles 530 and 532 can be separated by an air gap 552. Because the air can have a lower breakdown voltage than the Epoxy resin, the metal particles exposed on the diced surfaces 502/504 can provide a leakage current path with reduced resistance. For example, referring to
Referring to
In operation 904, at least some of the metal particles can be coated with a layer of a first insulation material (e.g., insulation layer 602). Examples of the first insulation material can include silicon dioxide and phosphate. Referring again to
In some examples, reagent 1008 can create X—OH or X—OR bond to coat an insulation layer on the surface of metal particles 1002, where X represents Si (silicon) or P (phosphorus), OH represents Hydroxide, and R represents an alkyl substituent. Different reagents 1008 can be used to coat different insulation materials on metal particles 1002. For example, to coat a layer of silicon dioxide on metal particles 1002, a reagent including an orthosilicate, such as tetraethyl orthosilicate (Si(OC2H5)4), can be used in operation 904. Also, to coat a layer of phosphate on metal particles 1002, a reagent including a phosphoric acid, such as orthophosphoric acid (H3PO4), can be used in operation 904.
In operation 906, the metal particles coated with the insulation layer can be separated from the solvent. The separation can be performed by, for example, passing slurry 1006 through a filter to remove solvent 1004 and reagent 1008 while retaining the metal particles, followed by washing and drying the metal particles.
In operation 906, the metal particles coated with the insulation layer can be mixed with a second insulation material to form a magnetic molding compound (MMC) material. The second insulation material can include Epoxy resin. As part of operation 906, the metal particles can be mixed with Epoxy resin, followed by a kneading operation in which the mixture can be kneaded with an extruder. The kneaded mixture can be made into a particular shape (e.g., a sheet) and cooled. The MMC material can then be crushed into particles, which can be melted and molded to form encapsulation package 208.
In operation 1102, multiple semiconductor dies can be mounted on a substrate.
Referring to
Also, referring to
Further, referring to
Referring again to
Referring to
Referring to
Referring to
In some examples, the dicing can be performed to remove some of the metal particles from the magnetic material to create cavities, which can be filled with air or another insulation material such as Epoxy resin. Removal of metal particles can be performed by increasing the contact time between the metal particles and the blade during the dicing operation. The contact time can be increased by decreasing the speed at which the blade moves across the dicing surface (e.g., the dicing speed), decreasing the rotation speed of the blade (e.g., the spindle speed), or both, so that the force exerted by the blade on the metal particles can overcome the bonding force between the metal particles and the Epoxy resin.
Also, as described above the cavities can be filled with air or another insulation material, such as Epoxy resin. After the dicing operation, a resin coating layer can be applied on the dicing surface to fill the cavities with resin. In some examples, the resin coating layer can be applied by a spray or by a spin coating operation.
Any of the methods described herein may be totally or partially performed with a computing system including one or more processors, which can be configured to perform the steps. Thus, embodiments can be directed to computing systems configured to perform the steps of any of the methods described herein, potentially with different components performing respective steps or a respective group of steps. Although presented as numbered steps, steps of methods herein can be performed at a same time or in a different order. Additionally, portions of these steps may be used with portions of other steps from other methods. Also, all or portions of a step may be optional. Additionally, any of the steps of any of the methods can be performed with modules, units, circuits, or other means for performing these steps.
In this description, the term “couple” may cover connections, communications or signal paths that enable a functional relationship consistent with this description. For example, if device A provides a signal to control device B to perform an action, then: (a) in a first example, device A is directly coupled to device B; or (b) in a second example, device A is indirectly coupled to device B through intervening component C if intervening component C does not substantially alter the functional relationship between device A and device B, so device B is controlled by device A via the control signal provided by device A.
A device that is “configured to” perform a task or function may be configured (e.g., programmed and/or hardwired) at a time of manufacturing by a manufacturer to perform the function and/or may be configurable (or reconfigurable) by a user after manufacturing to perform the function and/or other additional or alternative functions. The configuring may be through firmware and/or software programming of the device, through a construction and/or layout of hardware components and interconnections of the device, or a combination thereof.
A circuit or device that is described herein as including certain components may instead be adapted to be coupled to those components to form the described circuitry or device. For example, a structure described herein as including one or more semiconductor elements (such as transistors), one or more passive elements (such as resistors, capacitors and/or inductors), and/or one or more sources (such as voltage and/or current sources) may instead include only the semiconductor elements within a single physical device (e.g., a semiconductor die and/or integrated circuit (IC) package) and may be adapted to be coupled to at least some of the passive elements and/or the sources to form the described structure either at a time of manufacture or after a time of manufacture, such as by an end-user and/or a third party.
Certain components may be described herein as being of a particular process technology, but these components may be exchanged for components of other process technologies. Circuits described herein are reconfigurable to include the replaced components to provide functionality at least partially similar to functionality available prior to the component replacement. Components shown as resistors, unless otherwise stated, are generally representative of any one or more elements coupled in series and/or parallel to provide an amount of impedance represented by the shown resistor. For example, a resistor or capacitor shown and described herein as a single component may instead be multiple resistors or capacitors, respectively, coupled in series or in parallel between the same two nodes as the single resistor or capacitor.
Uses of the phrase “ground voltage potential” in this description include a chassis ground, an Earth ground, a floating ground, a virtual ground, a digital ground, a common ground, and/or any other form of ground connection applicable to, or suitable for, the teachings of this description. In this description, unless otherwise stated, “about,” “approximately” or “substantially” preceding a parameter means being within +/−10 percent of that parameter.
Modifications are possible in the described examples, and other examples are possible, within the scope of the claims.