JP2013108877A - Semiconductor device and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a small-sized current sensor with a high sensitivity and a high precision that can detect a magnetic field generated due to a current by integration with use of a compound semiconductor circuit.SOLUTION: A semiconductor circuit (LSI circuit) and a compound semiconductor circuit (compound semiconductor element having a hole element) are formed on a substrate, and an electric wiring is further formed immediately on the compound semiconductor element. The wiring is a metal wiring having a horseshoe shape to increase a magnetic flux density to the compound semiconductor circuit. A detected current is applied to the electric wiring.

Description

  The present invention relates to a semiconductor device and a manufacturing method thereof. Specifically, a semiconductor circuit (LSI (Large Scale Integration) circuit, etc.) and a compound semiconductor circuit (compound semiconductor element, etc.) are formed on the same substrate, and a primary conductor through which a detected current flows is also the same. The present invention relates to a small-sized, ultra-sensitive and highly accurate current detecting semiconductor device, particularly a current sensor structure.

  In an electric device such as an electric appliance that uses electricity as a power source, operation control according to the amount of current is performed, and excessive power supply is suppressed to reduce power consumption. Therefore, a current sensor is provided near the power wiring, the amount of current flowing is monitored, and the supply current is optimally controlled. In particular, in recent years, current sensors have been placed on electric vehicles, automobiles such as hybrid cars, mobile devices such as mobile phones, and relay bases for power transmission networks, solar power generation devices, etc. to accurately supply power. The importance of monitoring and controlling the amount of current is increasing.

  One of the main elements currently used as a current sensor is a Hall element. The Hall elements are roughly classified into two types: silicon Hall elements and compound semiconductor Hall elements. Each current sensor has advantages and disadvantages. Specifically, in a current sensor using a silicon Hall element, the Hall element and the arithmetic circuit can be formed on one chip, so that the size can be reduced. However, the sensitivity of the silicon Hall element is low.

  Therefore, in Patent Document 1, a lead frame in a package for sealing and fixing an element is used as a conducting wire (primary conductor) through which a current to be detected flows, and a silicon Hall element is disposed on the lead frame to thereby detect the current to be detected. An attempt has been made to increase the magnetic field detection sensitivity by bringing a flowing conductor (primary conductor) and a silicon Hall element close to each other and detecting a magnetic field generated when a current flows through the wiring as close as possible.

Patent 7709754B2

  However, in the configuration described in Patent Document 1, there is a large positional error when the semiconductor chip is arranged on the lead frame during assembly, and the element is accurately and accurately placed at a location where the magnetic field generated by the detected current is collected at the highest density. It is difficult to place. Therefore, there is a problem that the current detection sensitivity as a current sensor varies from product to product.

  In addition, the distance between the silicon Hall element and the lead frame is also limited by the silicon substrate thickness, and it is difficult to reduce the substrate thickness to 50 μm or less even with the current backside polishing technology, which further increases the magnetic field detection sensitivity. It is not possible.

  On the other hand, the compound semiconductor Hall element has higher magnetic field detection sensitivity than the silicon Hall element, but in the current technology, two chips of the compound semiconductor Hall element and the arithmetic circuit (silicon LSI) are manufactured separately. They are assembled and used in one PKG. Therefore, there is a drawback that the product size becomes larger than the current sensor using the silicon Hall element. In other words, in the existing current sensor product, a product satisfying all three elements of small size, high sensitivity, and high accuracy cannot be realized.

  A semiconductor device according to the present invention includes a semiconductor substrate, a semiconductor circuit formed in a first region on the semiconductor substrate, a compound semiconductor circuit formed in a second region on the semiconductor substrate, an upper portion of the semiconductor circuit, A silicon nitride film formed in the first region including the side surface facing the compound semiconductor circuit, a first electric wiring portion that electrically connects the semiconductor circuit and the compound semiconductor circuit, and a compound semiconductor circuit are formed. And a second electric wiring portion that is wired immediately above the second region and has a predetermined shape for increasing the magnetic flux density with respect to the compound semiconductor circuit immediately below the second region.

  The second electrical wiring portion having a predetermined shape may be a metal wiring having a U shape or a horseshoe shape.

  A space may be further provided between the second electrical wiring portion and the compound semiconductor circuit.

  The space may be a sealed space filled with vacuum or gas.

  The semiconductor circuit and the compound semiconductor circuit may be electrically connected through a hole formed in the silicon nitride film.

  The second electrical wiring portion may be formed at a height of 1 um to 20 um in the upper part of the compound semiconductor circuit.

  The second electric wiring portion may include any of Al, Cu, and Au.

  The second electrical wiring portion may have a thickness of 1 μm to 20 μm and a width of 1 μm to 20 μm.

  The semiconductor substrate may be a silicon substrate.

  The semiconductor circuit may be an LSI circuit.

  The compound semiconductor circuit may be a compound semiconductor element.

  The compound semiconductor element may be a Hall element.

  A method of manufacturing a semiconductor device according to the present invention includes a step of forming a semiconductor circuit in a first region on a semiconductor substrate, applying an insulating film to the entire region including the semiconductor circuit, and forming the insulating film on the semiconductor substrate. A step of removing a part to form a second region for forming a compound semiconductor circuit, and forming a silicon nitride film in the first region including an upper portion of the semiconductor circuit and a side surface facing the compound semiconductor circuit Electrically connecting the semiconductor circuit and the compound semiconductor circuit to each other by the first electrical wiring portion, the step of forming the compound semiconductor circuit in the second region on the semiconductor substrate from which the insulating film has been removed And a second electric wiring portion having a predetermined shape for increasing the magnetic flux density with respect to the compound semiconductor circuit immediately below the second region where the compound semiconductor circuit is formed. And the process of And said that there were pictures.

  According to the present invention, a substrate on which a semiconductor circuit (such as an LSI circuit) and a compound semiconductor circuit (such as a compound semiconductor element having a Hall element) are formed, and further directly above the compound semiconductor circuit, the compound semiconductor directly below the semiconductor circuit. An electrical wiring having a predetermined shape (for example, a metal wiring having a U-shape or a horseshoe shape) for increasing the magnetic flux density with respect to the circuit is formed, and a current to be detected is caused to flow through the wiring. Therefore, it is possible to realize a small, highly sensitive and highly accurate current sensor that can collect and detect the magnetic field generated by the current with the compound semiconductor circuit.

1 is a cross-sectional view of a semiconductor device according to a first embodiment of the present invention. FIG. 2 is a plan view showing a relative position between a Hall element and a Cu wiring in the semiconductor device of FIG. 1. 2 is a flowchart showing a manufacturing method of the semiconductor device of FIG. It is sectional drawing of the semiconductor device which is the 2nd Embodiment of this invention.

[First example]
(Device configuration)
A first embodiment of the present invention will be described with reference to FIGS.

  1 and 2 show a configuration example of a semiconductor device according to the present invention.

  The semiconductor device 100 includes a semiconductor substrate 101, a semiconductor circuit 113 formed in a first region on the semiconductor substrate 101, a compound semiconductor circuit 102 formed in a second region on the semiconductor substrate 101, and a semiconductor circuit 113. And a silicon nitride film 107 formed in a first region including a side surface facing the compound semiconductor circuit 102, a first electric wiring portion 109 that electrically connects the semiconductor circuit 113 and the compound semiconductor circuit 102, The second electric wiring portion wired in the upper part of the second region where the compound semiconductor circuit 102 is formed and having a predetermined shape for increasing the magnetic flux density with respect to the compound semiconductor circuit 102 immediately below the second region 111.

(Production method)
FIG. 3 is a flowchart showing a manufacturing process of the semiconductor device 100.

  In step S <b> 1, the semiconductor circuit 113 is formed in the first region A on the semiconductor substrate 101, and the insulating film 106 is applied to the entire region including the semiconductor circuit 113.

  In step S2, a part of the insulating film 106 on the semiconductor substrate 101 is removed to form a second region B for forming the compound semiconductor circuit 102.

  In step S <b> 3, a silicon nitride film (SiN) 107 is formed in the first region A including the upper portion of the semiconductor circuit 113 and the side surface facing the compound semiconductor circuit 102.

  In step S4, the compound semiconductor circuit 102 is formed in the second region B on the semiconductor substrate 101 from which the insulating film 107 has been removed.

  In step S <b> 5, the semiconductor circuit 113 and the compound semiconductor circuit 102 are electrically connected by the first electrical wiring unit 109.

  In step S6, the second electric wiring portion having a predetermined shape for increasing the magnetic flux density with respect to the compound semiconductor circuit 102 immediately below the second region B where the compound semiconductor circuit 102 is formed. 111 is formed.

<Specific example>
Hereinafter, a method for manufacturing the semiconductor device 100 will be described with specific examples.

First, as shown in FIG. 1, a silicon LSI circuit (semiconductor circuit) 113 is formed in a desired area (first region A) on a Si single crystal substrate (semiconductor substrate) 101 without a top layer protective film. Then, the entire silicon LSI circuit 113 is covered with the SiO ₂ layer (insulating film) 106 (step S1). In this case, the silicon LSI circuit (semiconductor circuit) 113 includes the Si semiconductor device circuit 104 and the metal wiring 105.

Next, the SiO ₂ layer 106 which is an interlayer film in a desired area (second region B) is removed, and only the substrate surface of the Si single crystal substrate 101 in the desired area is exposed (step S2).

  Next, a silicon nitride (SiN) film 107 that serves to protect the silicon LSI circuit 113 is formed on the entire surface of the wafer including the upper and side surfaces of the silicon LSI circuit 113 (step S3).

  Then, only the SiN film 107 in the area (second region B) where the compound semiconductor element is formed is removed to expose the substrate surface of the Si single crystal substrate 101, and the exposed substrate surface of the Si single crystal substrate 101 is exposed. Is terminated with a hydrogen atom.

  Next, the Si single crystal substrate 101 whose substrate surface is exposed is introduced into an MBE (Molecular Beam Epitaxy) apparatus. Then, by irradiating the compound semiconductor constituent material onto the Si single crystal substrate 101, an extremely high quality compound semiconductor film is directly formed on the exposed Si single crystal substrate 101.

  Further, in the area (second region B) in which the compound semiconductor film is directly formed on the Si single crystal substrate 101, the compound semiconductor film is processed into a desired shape to form the compound semiconductor element (compound semiconductor circuit) 102. (Step S4). In this case, a Hall element is particularly formed as the compound semiconductor element. Thereafter, a protective film 108 of the compound semiconductor element is formed.

  Next, as shown in FIG. 2, a contact hole 112 for electrically connecting the silicon LSI circuit 113 and the compound semiconductor element 102 is provided, and through this contact hole 112, a metal wiring (first electric wiring portion) is provided. 109 is provided (step S5).

  Thereby, the silicon LSI circuit 113 and the compound semiconductor element 102 can be simultaneously formed on the same Si single crystal substrate 101, and at the same time, the compound semiconductor element 102 and the silicon LSI 113 can be electrically connected.

Next, in order to protect the compound semiconductor element 102 and the metal wiring 109, an interlayer film 110 made of a SiO ₂ film or a SiN film is formed. Further, after an UBM (under bump metal) film is formed on the interlayer film 110, a metal wiring (second electric wiring portion) 111 mainly composed of Al, Cu, or Au is formed by using a plating technique. (Step S6).

  The metal wiring 111 has a predetermined shape for increasing the magnetic flux density with respect to the compound semiconductor element 102 directly below. For example, as shown in FIG. 2, the upper part of the Hall element that is the compound semiconductor element 102 has a U-shaped or horseshoe-shaped shape. As a result, the magnetic field generated when a current flows through the metal wiring 111 containing Al, Cu, or Au as a main component increases the magnetic flux density due to the U-shaped or horseshoe-shaped shape, and the compound semiconductor Hall element 102 immediately below is formed. Increases the magnetic field strength that can be perceived.

  In this example, the distance between the metal wiring 111 having a U-shaped or horseshoe-shaped shape and the Hall element which is the compound semiconductor element 102 is about 7 μm. This distance depends on the number of LSI wirings in the LSI portion. Height is rate limiting. Therefore, it is possible to reduce the number of laminated circuit wirings in the LSI portion, and it is more preferable if the number can be reduced to 1 μm.

  On the other hand, if the number of stacked wirings in the silicon LSI circuit 113 is increased, the distance between the U-shaped or horseshoe-shaped metal wiring 111 and the Hall element 102 is increased. As a result, the detection sensitivity and accuracy as a current sensor are increased. Although it tends to decrease, the most preferable sensitivity and detection accuracy in the current technology can be maintained by suppressing the distance to a maximum of about 20 μm.

  By the above procedure, the compound semiconductor element 102 for detecting the magnetic field, the metal wiring 111 as the primary conductor for flowing the current to be detected, and the silicon LSI circuit 113 for relaying / processing the signal output from the compound semiconductor element 102 are the same. The semiconductor chip can be integrally formed. As a result, it is possible to form a semiconductor chip for a current sensor that is small, highly sensitive, and highly accurate.

  When this semiconductor chip is assembled with plastic PKG, the end of the metal wiring 111 having a U-shape or a horseshoe shape is electrically connected to the terminal of the package using Au wire or the like by wire bonding technology. By applying a current to be detected to this terminal, the current to be detected flows through a metal wiring 111 having a U-shape or a horseshoe shape provided immediately above the Hall element as the compound semiconductor element 102, whereby the amount of current is detected. A magnetic field proportional to is generated, and this magnetic field is detected by a Hall element provided immediately below.

  Furthermore, since the distance between the metal wiring 111 having a U-shape or a horseshoe shape and the Hall element that is the compound semiconductor element 102 is short, it is possible to detect a very small change in the amount of current with high accuracy.

[Second example]
Next, a second embodiment of the present invention will be described with reference to FIG. In addition, about the same part as the 1st example mentioned above, the description is abbreviate | omitted and the same code | symbol is attached | subjected.

  FIG. 4 shows a configuration example of the semiconductor device 100.

  This example is characterized in that a space 114 is further provided between the metal wiring 111 as the second electrical wiring portion and the Hall element which is the compound semiconductor element 102 as the compound semiconductor circuit.

  Hereinafter, a specific example of the space 114 will be described. Note that the overall configuration of the semiconductor device 100 and the manufacturing method thereof are the same as those in the first example, and thus description thereof is omitted here.

  The height between the U-shaped or horseshoe-shaped metal wiring 111 and the Hall element, which is the compound semiconductor element 102, is 1 μm or more and 20 μm as shown in FIG. 4 by using MEMS (Micro Electro Mechanical Systems) technology. In the following, a space 114 having a volume of 1 μm 3 or more and 1,000,000 μm 3 or less is provided.

Further, a protective film such as a SiO ₂ film or a SiN film is formed on the space 114 by using PCVD (Plasma Chemical Vapor Deposition) technology, so that the space between the metal wiring 111 and the Hall element which is the compound semiconductor element 102 is formed. The space 114 provided in is completely sealed.

Since the space 114 thus configured is sealed when the SiO ₂ film or the SiN film is formed in the PCVD apparatus, the space 114 is filled with a vacuum state or a low-pressure gas used for protection formation. It is in the state.

  Thus, by providing the sealed space 114 between the U-shaped or horseshoe-shaped metal wiring 111 and the Hall element which is the compound semiconductor element 102, the space 114 becomes a buffer region, and external stress is applied. Can be reduced to be applied to the Hall element. As a result, fluctuations in the magnetic detection sensitivity of the Hall element due to stress can be suppressed, and the magnetic field can be detected with higher accuracy.

  Through the above procedure, the space 114, the Hall element that is the compound semiconductor element 102 that detects the magnetic field, the metal wiring 111 that is the primary conductor for passing the current to be detected, and the signal output from the compound semiconductor element 102 are relayed / calculated. The silicon LSI circuit 113 to be integrated can be integrally formed in the same semiconductor chip, whereby it is possible to form a semiconductor chip for a current sensor that is small, highly sensitive, and more highly accurate. .

  In the present invention, a Hall element that is a highly sensitive compound semiconductor element, an LSI circuit that calculates a signal output from the Hall element, and a conductor through which a current to be detected flows are integrally formed in the same semiconductor chip. Therefore, it is possible to supply a small-sized, highly sensitive and highly accurate semiconductor device, particularly a current sensor.

101 Si single crystal substrate 102 Compound semiconductor element (Hall element)
104 Si Semiconductor Device in Silicon LSI Circuit 105 Metal Wiring in Silicon LSI Circuit 106 SiO ₂ Interlayer Film 107 SiN Protective Film 108 Protective Film 109 Metal Wiring 110 Interlayer Film 111 Cu Wiring Presenting a U-Shape Right Above the Hall Element 112 Contact Hole 113 Silicon LSI circuit 114 Space provided between primary conductor wiring and Hall element

Claims (20)

A semiconductor device,
A semiconductor substrate;
A semiconductor circuit formed in a first region on the semiconductor substrate;
A compound semiconductor circuit formed in a second region on the semiconductor substrate;
A silicon nitride film formed in the first region including an upper portion of the semiconductor circuit and a side surface facing the compound semiconductor circuit;
A first electrical wiring portion for electrically connecting the semiconductor circuit and the compound semiconductor circuit;
A second electrical wiring portion that is wired immediately above the second region where the compound semiconductor circuit is formed and has a predetermined shape for increasing a magnetic flux density with respect to the compound semiconductor circuit immediately below the second region. A semiconductor device characterized by comprising.   2. The semiconductor device according to claim 1, wherein the second electric wiring portion having the predetermined shape is made of a metal wiring having a U-shape or a horseshoe shape.   3. The semiconductor device according to claim 1, further comprising a space between the second electric wiring portion and the compound semiconductor circuit.   4. The semiconductor device according to claim 3, wherein the space is a sealed space filled with vacuum or gas.   5. The semiconductor device according to claim 1, wherein the semiconductor circuit and the compound semiconductor circuit are electrically connected through a hole formed in the silicon nitride film.   6. The semiconductor device according to claim 1, wherein the second electrical wiring portion is formed at a height of 1 μm or more and 20 μm or less of the upper portion of the compound semiconductor circuit.   7. The semiconductor device according to claim 1, wherein the second electric wiring portion includes any one of Al, Cu, and Au.   8. The semiconductor device according to claim 1, wherein the second electrical wiring portion has a thickness of 1 μm to 20 μm and a width of 1 μm to 20 μm. 9.   The semiconductor device according to claim 1, wherein the semiconductor substrate is a silicon substrate.   The semiconductor device according to claim 1, wherein the semiconductor circuit is an LSI circuit.   The semiconductor device according to claim 1, wherein the compound semiconductor circuit is a compound semiconductor element.   The semiconductor device according to claim 11, wherein the compound semiconductor element includes a Hall element. A method for manufacturing a semiconductor device, comprising:
Forming a semiconductor circuit in a first region on the semiconductor substrate and applying an insulating film to the entire region including the semiconductor circuit;
Removing a portion of the insulating film on the semiconductor substrate to form a second region for forming a compound semiconductor circuit;
Forming a silicon nitride film in the first region including an upper portion of the semiconductor circuit and a side surface facing the compound semiconductor circuit;
Forming the compound semiconductor circuit in the second region on the semiconductor substrate from which the insulating film has been removed;
Electrically connecting the semiconductor circuit and the compound semiconductor circuit by a first electrical wiring portion;
Forming a second electric wiring portion having a predetermined shape for increasing a magnetic flux density with respect to the compound semiconductor circuit immediately below the second region where the compound semiconductor circuit is formed; A method for manufacturing a semiconductor device, comprising:   14. The method of manufacturing a semiconductor device according to claim 13, wherein the second electric wiring portion having the predetermined shape is made of a metal wiring having a U-shaped or horseshoe-shaped shape.   15. The method of manufacturing a semiconductor device according to claim 13, further comprising a step of providing a space between the second electric wiring portion and the compound semiconductor circuit.   16. The method of manufacturing a semiconductor device according to claim 15, wherein the space is a sealed space filled with vacuum or gas.   16. The method of manufacturing a semiconductor device according to claim 13, wherein the semiconductor substrate is a silicon substrate.   The method of manufacturing a semiconductor device according to claim 13, wherein the semiconductor circuit is an LSI circuit.   The method of manufacturing a semiconductor device according to claim 13, wherein the compound semiconductor circuit is a compound semiconductor element.   19. The method of manufacturing a semiconductor device according to claim 18, wherein the compound semiconductor element includes a Hall element.

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