Single-chip current sensor and method of manufacturing the same

Abstract

The application provides a single-chip current sensor and a manufacturing method thereof, the single-chip current sensor comprising a signal processing circuit, a magnetic sensor and a current trace formed based on a same substrate, wherein the signal processing circuit and the magnetic sensor are electrically connected through a via metal. Compared with the prior art, the signal processing circuit, the magnetic sensor and the current trace are integrated on the same substrate, so that the single-chip current sensor has high integration and low cost.

Description

[Technical Field]

[0001] This invention relates to the field of semiconductor device manufacturing, and more particularly to a single-chip current sensor and its manufacturing method. [Background Technology]

[0002] Current sensors, used to measure current magnitude, are widely used in various electronic devices. However, traditional current sensors assemble signal processing circuits, magnetoresistive sensors, and current traces together through packaging processes. The disadvantages are low integration density and high cost.

[0003] Therefore, it is necessary to propose a technical solution to overcome the above problems. [Summary of the Invention]

[0004] One of the objectives of this invention is to provide a single-chip current sensor and its manufacturing method, which has high integration and low cost.

[0005] According to one aspect of the present invention, a single-chip current sensor is provided, comprising: a signal processing circuit, a magnetic sensor, and a current trace formed on the same substrate, wherein the signal processing circuit and the magnetic sensor are electrically connected via vias.

[0006] Furthermore, the via metal is patterned from a deposited first metal layer; the current trace is patterned from a deposited second metal layer; and the magnetic sensor is patterned from a deposited magnetized thin film.

[0007] Furthermore, the signal processing circuit is located on the substrate; the magnetic sensor is located above the signal processing circuit; and the current trace is located above the magnetic sensor.

[0008] Furthermore, the single-chip current sensor further includes: a first insulating dielectric layer located between the magnetic sensor and the signal processing circuit, wherein the via metal passes through the first insulating dielectric layer; and a second insulating dielectric layer located between the current trace and the magnetic sensor.

[0009] Furthermore, a first through-hole is formed within the first insulating dielectric layer, penetrating its thickness, and the bottom of the first through-hole exposes the signal processing circuit; the via metal fills the first contact hole and covers the top of the first contact hole.

[0010] Furthermore, the single-chip current sensor also includes a third insulating dielectric layer, which is located above the first insulating dielectric layer and the via metal, and below the magnetic sensor. A second through hole is formed in the third insulating dielectric layer, penetrating its thickness. The bottom of the second through hole exposes the via metal. A portion of the connection end of the magnetic sensor fills the second through hole to electrically connect with the via metal.

[0011] Furthermore, the current trace is a U-shaped trace, which includes a first leg, a second leg, and a connecting portion connecting the first leg and the second leg; the magnetic sensor is a magnetoresistive sensor, which includes a first magnetoresistive sensor unit and a second magnetoresistive sensor unit, the first magnetoresistive sensor unit and the second magnetoresistive sensor unit being opposite to the first leg and the second leg of the U-shaped trace, respectively, to form a differential output.

[0012] According to another aspect of the present invention, a method for manufacturing a single-chip current sensor is provided, comprising: providing a substrate and fabricating a signal processing circuit on the substrate; depositing a first insulating dielectric layer over the signal processing circuit and forming a first via through its thickness within the first insulating dielectric layer, the bottom of the first via exposing the signal processing circuit; depositing and patterning a first metal layer over the first insulating dielectric layer and within the first via to obtain the via metal; depositing and patterning a magnetic thin film over the via metal and the first insulating dielectric layer to obtain the magnetic sensor, wherein a connection terminal of the magnetic sensor is electrically connected to the via metal; and depositing and patterning a second metal layer over the magnetic sensor to obtain the current trace.

[0013] Furthermore, before the step of depositing a second metal layer and patterning it above the magnetic sensor, the method further includes the following step: depositing a second insulating dielectric layer above the magnetic sensor, wherein the second insulating dielectric layer is located between the magnetic sensor and the current trace.

[0014] Furthermore, before the step of depositing and patterning a magnetic thin film above the via metal and the first insulating dielectric layer, the method further includes the following step: depositing the third insulating dielectric layer above the via metal and the first insulating dielectric layer, and forming a second through-hole penetrating its thickness within the third insulating dielectric layer, the bottom of the second through-hole exposing the via metal, wherein the third insulating layer is located above the first insulating dielectric layer and the via metal and below the magnetic sensor, and a portion of the connection end of the magnetic sensor fills the second through-hole to electrically connect with the via metal.

[0015] Compared with the prior art, the present invention integrates the signal processing circuit, magnetic sensor and current line on the same substrate, thereby making the single-chip current sensor of the present invention highly integrated and low cost. [Attached Image Description]

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0017] Figure 1 This is a longitudinal cross-sectional schematic diagram of a single-chip current sensor in one embodiment of the present invention;

[0018] Figure 2 This is a schematic flowchart of a method for manufacturing a single-chip current sensor according to one embodiment of the present invention;

[0019] Figures 3-9 In one embodiment of the present invention, Figure 2 The longitudinal section views corresponding to each step shown;

[0020] Figure 10 for Figure 1 The diagram shows a structural schematic of a single-chip current sensor in one embodiment.

Detailed Implementation Methods

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] The term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the invention. The phrase "in one embodiment" appearing in different places throughout this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that excludes other embodiments. Unless otherwise specified, the terms "connected," "linked," and "connected" used herein to indicate electrical connection refer to direct or indirect electrical connection.

[0023] Please refer to Figure 1 As shown, it is a longitudinal cross-sectional schematic diagram of a single-chip current sensor in one embodiment of the present invention. Figure 1 The single-chip current sensor shown includes a signal processing circuit 102, a magnetic sensor 106, and a current trace 108 formed on the same silicon substrate (or semiconductor substrate) 101, wherein the signal processing circuit 102 and the magnetic sensor 106 are electrically connected through a via metal 104.

[0024] The via metal 104 is patterned from a deposited first metal layer; the current trace 108 is patterned from a deposited second metal layer; and the magnetic sensor 106 is patterned from a deposited magnetized thin film.

[0025] The signal processing circuit 102, the magnetic sensor 106, and the current trace 108 are stacked on the silicon substrate 101. Specifically, the signal processing circuit 102 is located on the substrate 101; the magnetic sensor 106 is located above the signal processing circuit 102; and the current trace 108 is located above the magnetic sensor 106.

[0026] exist Figure 1 In the specific embodiment shown, the single-chip current sensor further includes a first insulating dielectric layer 103, a second insulating dielectric layer 107, and a third insulating dielectric layer 105.

[0027] The first insulating dielectric layer 103 is located between the magnetic sensor 106 and the signal processing circuit 102. Specifically, the first insulating dielectric layer 103 is deposited (or located) above the signal processing circuit 102, and a first through hole (unmarked) is formed in the first insulating dielectric layer 103, penetrating its thickness, and the bottom of the first through hole exposes the signal processing circuit 102.

[0028] The via metal 104 passes through the first contact hole (or the via metal 104 passes through the first insulating dielectric layer 103). Specifically, the via metal 104 is patterned from a first metal layer deposited above the first insulating dielectric layer 103. The via metal 104 fills the first contact hole and covers the top of the first contact hole.

[0029] The third insulating dielectric layer 105 is located above the first insulating dielectric layer 103 and the via metal 104, and below the magnetic sensor 106. Specifically, the third insulating dielectric layer 105 is deposited (or located) above the via metal 104 and the first insulating dielectric layer 103, and a second through-hole (unmarked) is formed within the third insulating dielectric layer 105, penetrating its thickness, with the bottom of the second through-hole exposing the via metal 104.

[0030] The magnetic sensor 106 is patterned from a magnetic thin film deposited on the third insulating dielectric layer 105. Part of the connection end (or part of the wiring) of the magnetic sensor 106 fills (or passes through) the second through hole to be electrically connected to the through hole metal 104.

[0031] The second insulating dielectric layer 107 is located between the current trace 108 and the magnetic sensor 106. Specifically, the second insulating dielectric layer 107 is deposited (or located) above the magnetic sensor 106, and the second insulating dielectric layer 107 is used to electrically isolate the magnetic sensor 106 and the current trace 108.

[0032] The current trace 108 is patterned from a second metal layer (or thick metal layer) deposited (or located) above the second insulating dielectric layer 107.

[0033] Please refer to Figure 2 The diagram shown is a flowchart illustrating a method for manufacturing a single-chip current sensor according to one embodiment of the present invention; please refer to... Figures 3-9 As shown, this is one embodiment of the present invention. Figure 2 The longitudinal section diagrams corresponding to each step are shown. Figure 2 The manufacturing method of the single-chip current sensor shown includes the following steps.

[0034] Step 210, as follows Figure 3 As shown, a silicon substrate (or semiconductor) 101 is provided, and a signal processing circuit 102 is fabricated (or obtained) on the silicon substrate 101 by semiconductor process.

[0035] Step 220, as follows Figure 4 As shown, a first insulating dielectric layer 103 is deposited above the signal processing circuit 102, and a first through-hole 109 is formed in the first insulating dielectric layer 103, penetrating its thickness, with the bottom of the first through-hole 109 exposing the signal processing circuit 102.

[0036] Step 230, as follows Figure 5 As shown, the first metal layer is deposited and patterned over the first insulating dielectric layer 103 and inside the first through hole 109 to form the via metal 104, which fills the first contact hole 109 and covers the top of the first contact hole 109.

[0037] Step 240, as follows Figure 6 As shown, a third insulating dielectric layer 105 is deposited above the via metal 104 and the first insulating dielectric layer 103, and a second through-hole 110 is formed in the third insulating dielectric layer 105, penetrating its thickness, with the bottom of the second through-hole 110 exposing the via metal 104.

[0038] Step 250, as follows Figure 7As shown, a magnetic thin film is deposited and patterned over the third insulating dielectric layer 105 and within the second through-hole 110 to fabricate the magnetic sensor 106. A portion of the connection end (or a portion of the wiring) of the magnetic sensor 106 fills (or passes through) the second through-hole 110 and is electrically connected to the via metal 104.

[0039] Step 260, as follows Figure 8 As shown, a second insulating dielectric layer 107 is deposited above the magnetic sensor 106.

[0040] Step 270, as follows Figure 9 As shown, a second metal layer is deposited and patterned over the second insulating dielectric layer 107 to form the current trace 108.

[0041] In summary, based on Figure 2 The method shown for manufacturing a single-chip current sensor can produce... Figure 1 The single-chip current sensor shown.

[0042] Please refer to Figure 10 As shown, it is Figure 1 The diagram shows a structural schematic of a single-chip current sensor in one embodiment. Figure 10 In the embodiment shown, the signal processing circuit 102, the magnetic sensor 106, and the current trace 108 are integrated on the same substrate 101.

[0043] The current trace 108 provides a path for the measured current I. The current trace 108 is U-shaped and includes a first leg 108a, a second leg 108b, and a connecting portion 108c. The first leg 108a and the second leg 108b are located on the same side of the connecting portion 108c. One end of the first leg 108a serves as the current input terminal of the U-shaped trace 108, and the other end of the first leg 108a is connected to one end of the connecting portion 108c. One end of the second leg 108b serves as the current output terminal of the U-shaped trace 108, and the other end of the second leg 108b is connected to the other end of the connecting portion 108c.

[0044] The magnetic sensor 106 is a magnetoresistive sensor, which includes a first magnetoresistive sensor unit 106a and a second magnetoresistive sensor unit 106b. The first magnetoresistive sensor unit 106a and the second magnetoresistive sensor unit 106b are respectively opposite to the first leg 108a and the second leg 108b of the U-shaped trace 108 to form a differential output.

[0045] The current I in the current trace 108 generates a magnetic field H at the first resistance sensor unit 106a. 11A magnetic field -H is generated at the second resistance sensor unit 106b. 12 The output of the first magnetoresistive sensor unit 106a is V. 11 =S[(H 11 / I)I+H0], where S is the sensitivity of the magnetoresistive sensor unit relative to the magnetic field, and H0 is the external magnetic field; the output of the second magnetoresistive sensor unit 106b is V 12 =S[-(H 12 / I)I+H0];The output of the magnetoresistive sensor 106 is V1=S[(H 11 +H 12 ) / I]I.

[0046] In summary, the single-chip current sensor of the present invention includes the signal processing circuit 102, the magnetic sensor 106 and the current trace 108 integrated on the same substrate, and the signal processing circuit 102 and the magnetic sensor 106 are electrically connected through a via metal 104, thereby enabling the single-chip current sensor of the present invention to have high integration and low cost.

[0047] In this invention, terms such as “connection,” “linked,” “connected,” and “joined” that indicate electrical connection, unless otherwise specified, indicate direct or indirect electrical connection.

[0048] The above description is only a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. Any equivalent modifications or changes made by those skilled in the art based on the disclosure of the present invention should be included within the scope of protection set forth in the claims.

Claims

1. A single-chip current sensor, characterized in that, It includes: Signal processing circuits, magnetic sensors, and current traces are all based on the same substrate. The signal processing circuit is electrically connected to the magnetic sensor via a through-hole. The via metal is obtained by patterning a deposited first metal layer; The current traces are patterned from a deposited second metal layer; The magnetic sensor is fabricated by patterning a deposited magnetic thin film. The signal processing circuit is located on the substrate; The magnetic sensor is located above the signal processing circuit; The current trace is located above the magnetic sensor. It also includes: A first insulating dielectric layer is located between the magnetic sensor and the signal processing circuit, the first insulating dielectric layer is deposited above the signal processing circuit, and the via metal passes through the first insulating dielectric layer; A second insulating dielectric layer is located between the current trace and the magnetic sensor; A third insulating dielectric layer is located above the first insulating dielectric layer and the via metal, and below the magnetic sensor. A first through-hole is formed in the first insulating dielectric layer, penetrating its thickness, and the bottom of the first through-hole exposes the signal processing circuit. The via metal fills the first through hole and covers the top of the first through hole. A second through-hole is formed within the third insulating dielectric layer, penetrating its thickness, with the bottom of the second through-hole exposing the via metal. The magnetic sensor partially fills the second through hole to make a metallic electrical connection with the through hole.

2. The single-chip current sensor according to claim 1, characterized in that, The current trace is a U-shaped trace, which includes a first leg, a second leg, and a connecting portion connecting the first leg and the second leg. The magnetic sensor is a magnetoresistive sensor, which includes a first magnetoresistive sensor unit and a second magnetoresistive sensor unit. The first magnetoresistive sensor unit and the second magnetoresistive sensor unit are respectively opposite to the first leg and the second leg of the U-shaped trace to form a differential output.

3. A method for manufacturing a single-chip current sensor, characterized in that, It includes: A substrate is provided, and a signal processing circuit is fabricated on the substrate; A first insulating dielectric layer is deposited above the signal processing circuit, and a first through-hole is formed in the first insulating dielectric layer, penetrating its thickness, with the bottom of the first through-hole exposing the signal processing circuit. A first metal layer is deposited and patterned over the first insulating dielectric layer and inside the first via to obtain via metal; A third insulating dielectric layer is deposited above the via metal and the first insulating dielectric layer, and a second through-hole is formed in the third insulating dielectric layer, penetrating its thickness, with the bottom of the second through-hole exposing the via metal; A magnetically fused thin film is deposited and patterned over the third insulating dielectric layer and inside the second via to obtain a magnetic sensor, wherein the connection end of the magnetic sensor is electrically connected to the via metal. A second insulating dielectric layer is deposited above the magnetic sensor, wherein the second insulating dielectric layer is located between the magnetic sensor and the current trace; A second metal layer is deposited and patterned above the magnetic sensor to form the current trace. The third insulating dielectric layer is located above the first insulating dielectric layer and the via metal and below the magnetic sensor. Part of the connection end of the magnetic sensor fills the second through hole to electrically connect with the via metal.

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