CN-122003581-A - Inductive sensor device with inductor coils formed in redistribution layer (RDL) regions

Abstract

An inductive sensor device includes at least one die mounted in or on a substrate, a redistribution layer (RDL) region formed over the at least one die and including a plurality of RDL metal layers, and at least one inductor coil formed in the RDL region and including at least one conductive coil element formed in at least one of the plurality of RDL metal layers, wherein the at least one die includes sensor circuitry connected to the at least one inductor coil to perform a sensor measurement.

Inventors

• A. Ramamoursi
• K.M. SMITH
• B.CHEN

Assignees

• 微芯片技术股份有限公司

Dates

Publication Date

20260508

Application Date

20240411

Priority Date

20240116

Claims (20)

1. 1. An inductive sensor device, the inductive sensor device comprising: at least one die mounted in or on a substrate; A redistribution layer (RDL) region formed over the at least one die, the RDL region including a plurality of RDL metal layers, and At least one inductor coil formed in the RDL region, the at least one inductor coil including at least one conductive coil element formed in at least one RDL metal layer of the plurality of RDL metal layers; wherein the at least one die includes sensor circuitry connected to the at least one inductor coil to perform sensor measurements.
2. 2. The inductive sensor apparatus of claim 1, wherein the at least one inductive coil comprises respective conductive coil elements formed in at least two RDL metal layers of the plurality of RDL metal layers.
3. 3. The inductive sensor apparatus of any one of claims 1-2, comprising a plurality of conductive signal routing elements formed in the RDL region, wherein (a) respective ones of the at least one conductive coil elements and (b) respective ones of the plurality of conductive signal routing elements are formed in a common RDL metal layer of the plurality of RDL metal layers.
4. 4. The inductive sensor apparatus of any one of claims 1 to 3, wherein: The at least one inductor coil includes a primary coil and at least one secondary coil, and The sensor circuit includes: an oscillator connected to the primary coil to generate a magnetic field from the primary coil, and A voltage detection circuit connected to the at least one secondary coil to detect a voltage at the at least one secondary coil.
5. 5. The inductive sensor apparatus of claim 4, wherein: The at least one secondary coil includes a first secondary coil and a second secondary coil, and The voltage detection circuit is connected to the first secondary coil and the second secondary coil so as to detect a first voltage at the first secondary coil and a second voltage at the second secondary coil, and calculate a ratio of the first voltage to the second voltage.
6. 6. The inductive sensor apparatus according to any one of claims 4 to 5, wherein: the primary coil includes at least one primary coil element formed in a first RDL metal layer of the plurality of RDL metal layers; The first secondary coil includes at least one first secondary coil element formed in a second RDL metal layer of the plurality of RDL metal layers, and The second secondary includes at least one second secondary coil element formed in a third RDL metal layer of the plurality of RDL metal layers.
7. 7. The inductive sensor apparatus of any one of claims 4 to 6, wherein the inductive sensor apparatus comprises a linear positioning sensor.
8. 8. The inductive sensor apparatus of any one of claims 4 to 6, wherein the inductive sensor apparatus comprises a rotation sensor.
9. 9. The inductive sensor device of any one of claims 1 to 8, wherein the inductive sensor device is formed as a System In Package (SiP) comprising the at least one die mounted in or on the substrate, the RDL area, and the at least one inductor coil formed in the RDL area.
10. 10. The inductive sensor apparatus of any one of claims 1 to 9, wherein said at least one die comprises a first die and a second die, and The RDL area includes at least one conductive routing element defining a conductive connection between the first die and the second die.
11. 11. The inductive sensor apparatus of any one of claims 1 to 10, wherein the at least one die comprises an analog die and a digital die.
12. 12. The inductive sensor apparatus of any one of claims 1 to 11, comprising an antenna coil comprising at least one conductive coil element formed in the RDL region.
13. 13. A method, the method comprising: Disposing at least one die on a carrier, the at least one die including a sensor circuit; Depositing an encapsulation material over the at least one die to form a substrate supporting the at least one die, and Forming a redistribution layer (RDL) region including a plurality of RDL metal layers over the at least one die, Wherein forming the RDL region includes forming at least one inductor coil including at least one conductive coil element in at least one RDL metal layer of the plurality of RDL metal layers, and Wherein the at least one inductor coil is connected to the sensor circuit in the at least one die.
14. 14. The method of claim 13, wherein forming the RDL region comprising a plurality of RDL metal layers comprises forming a plurality of RDL metal layers alternating with a plurality of RDL via layers, and forming a respective conductive coil element of the at least one inductor coil comprises forming a respective conductive coil element in at least two respective RDL metal layers of the plurality of RDL metal layers.
15. 15. The method of any one of claims 13 to 14, comprising forming a plurality of conductive signal routing elements in the RDL region, wherein (a) respective ones of the at least one conductive coil elements and (b) respective ones of the plurality of conductive signal routing elements are formed in a common RDL metal layer of the plurality of RDL metal layers.
16. 16. The method of any one of claims 13-15, wherein forming the at least one inductor coil comprises (a) forming a primary coil in a respective RDL metal layer of the plurality of RDL metal layers, and (b) forming at least one secondary coil in at least one other respective RDL metal layer of the plurality of RDL metal layers.
17. 17. The method of any one of claims 13 to 16, wherein forming the at least one inductor coil comprising at least one conductive coil element in at least one RDL metal layer of the plurality of RDL metal layers comprises: forming at least one primary coil element of a primary coil in a first RDL metal layer; At least one first secondary coil element forming a first secondary coil in a second RDL metal layer, and At least one second secondary coil element of a second secondary is formed in the third RDL metal layer.
18. 18. The method of any of claims 13 to 17, wherein the at least one die comprises a first die and a second die, and The method includes forming at least one conductive routing element in the RDL region to conductively connect the first die to the second die.
19. 19. A device formed by any one of the methods of claims 13 to 18.
20. 20. An inductive sensor device, the inductive sensor device comprising: at least one die mounted in or on a substrate; A redistribution layer (RDL) region formed over the at least one die, the RDL region comprising a plurality of RDL metal layers; A primary coil comprising a primary coil element formed in a first RDL metal layer of the plurality of RDL metal layers; A first secondary coil including a first secondary coil element formed in a second RDL metal layer of the plurality of RDL metal layers, and A second secondary coil comprising a second secondary coil element formed in a third RDL metal layer of the plurality of RDL metal layers; wherein the at least one die includes sensor circuitry connected to the primary coil, the first secondary coil, and the second secondary coil.

Description

Inductive sensor device with inductor coils formed in redistribution layer (RDL) regions Related patent application This patent application claims priority from commonly owned U.S. provisional patent application No. 63/543,606 filed on 10/11 2023, the entire contents of which are hereby incorporated by reference for all purposes. Technical Field The present disclosure relates to Integrated Circuit (IC) devices, and more particularly to inductive sensor devices including at least one inductor coil formed in a redistribution layer (RDL) region, and methods of forming such inductive sensor devices. Background Inductive sensors use the principle of electromagnetic induction to detect or measure objects. One type of inductive sensor is a proximity sensor or a positioning sensor for detecting the position and/or movement of an object (e.g., a metal object). The inductive position sensor may be constructed on a Printed Circuit Board (PCB), where the sensor includes an inductor coil formed from conductive traces on the PCB and connected to an integrated circuit, such as a microchip (e.g., a microcontroller) mounted on the PCB. Such PCB-based inductive position sensors typically occupy a large area (footprint) on the PCB. There is a need for an improved inductive sensor (e.g., an improved inductive position sensor), such as an inductive sensor having a reduced form factor (size) and/or cost as compared to conventional inductive sensors. Disclosure of Invention The present disclosure provides an inductive sensor device including at least one die mounted in or on a substrate, a redistribution layer (RDL) region formed over the die, and at least one inductive sensor coil formed in the RDL region. The RDL region may include a plurality of RDL metal layers alternating with via layers and the at least one inductive sensor coil may include an inductive coil element formed in one or more of the RDL metal layers. The inductive sensor coil formed in the RDL area may be connected to one or more underlying die that provide the respective functionality of the inductive sensor device, e.g., for detecting the positioning and/or movement of a target object proximate the inductive sensor device. The RDL area may also include conductive routing elements (along with the inductor coil elements) to route electrical signals between respective dies in the inductive sensor device and/or between respective dies in the inductive sensor device and external electronics. In some examples, the inductive sensor device may be formed as a System In Package (SiP). Inductive sensor devices (e.g., including one or more inductive sensor coils formed in an RDL region over one or more dies) as disclosed herein (e.g., embodied in a SiP) may be substantially smaller than conventional PCB-based inductive sensors. For example, the conductive structures in the RDL region may have a pitch in the range of 2 microns to 5 microns as compared to a typical PCB trace pitch of greater than 20 microns. Inductive sensor apparatus as disclosed herein may be used in a variety of applications, such as in industrial robots, motors, aircraft, and drones, but is not limited thereto. One aspect provides an inductive sensor device comprising at least one die mounted in or on a substrate, a redistribution layer (RDL) region formed over the at least one die, the RDL region comprising a plurality of RDL metal layers, and at least one inductor coil formed in the RDL region, the at least one inductor coil comprising at least one conductive coil element formed in at least one of the plurality of RDL metal layers, wherein the at least one die comprises sensor circuitry connected to the at least one inductor coil to perform a sensor measurement. In one example, the at least one inductor coil includes respective conductive coil elements formed in at least two RDL metal layers of the plurality of RDL metal layers. In one example, the inductive sensor device includes a plurality of conductive signal routing elements formed in the RDL region, wherein (a) respective ones of the at least one conductive coil elements and (b) respective ones of the plurality of conductive signal routing elements are formed in a common RDL metal layer of the plurality of RDL metal layers. In one example, the at least one inductor coil includes a primary coil and at least one secondary coil, and the sensor circuit includes (a) an oscillator connected to the primary coil to generate a magnetic field from the primary coil, and (b) a voltage detection circuit connected to the at least one secondary coil to detect a voltage at the at least one secondary coil. In one example, the at least one secondary coil includes a first secondary coil and a second secondary coil, and the voltage detection circuit is connected to the first secondary coil and the second secondary coil to detect a first voltage at the first secondary coil and a second voltage at the second secondary coil, and calculate a ratio of the first voltage