WO2014112179A1 - Signal transmission insulation device and power semiconductor module - Google Patents

Signal transmission insulation device and power semiconductor module Download PDF

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Publication number
WO2014112179A1
WO2014112179A1 PCT/JP2013/079537 JP2013079537W WO2014112179A1 WO 2014112179 A1 WO2014112179 A1 WO 2014112179A1 JP 2013079537 W JP2013079537 W JP 2013079537W WO 2014112179 A1 WO2014112179 A1 WO 2014112179A1
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WO
WIPO (PCT)
Prior art keywords
coil
insulating film
signal transmission
dielectric
power semiconductor
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PCT/JP2013/079537
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French (fr)
Japanese (ja)
Inventor
健一 菅
崇夫 釣本
塩田　裕基
健一 諸熊
西川　和康
昭一 折田
為谷　典孝
西田　信也
玲 米山
貴公 井上
紫織 魚田
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三菱電機株式会社
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Application filed by 三菱電機株式会社 filed Critical 三菱電機株式会社
Priority to JP2014557327A priority Critical patent/JP5855285B2/en
Publication of WO2014112179A1 publication Critical patent/WO2014112179A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/52—Arrangements for conducting electric current within the device in operation from one component to another, i.e. interconnections, e.g. wires, lead frames
    • H01L23/522—Arrangements for conducting electric current within the device in operation from one component to another, i.e. interconnections, e.g. wires, lead frames including external interconnections consisting of a multilayer structure of conductive and insulating layers inseparably formed on the semiconductor body
    • H01L23/532—Arrangements for conducting electric current within the device in operation from one component to another, i.e. interconnections, e.g. wires, lead frames including external interconnections consisting of a multilayer structure of conductive and insulating layers inseparably formed on the semiconductor body characterised by the materials
    • H01L23/5329—Insulating materials
    • H01L23/53295—Stacked insulating layers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F19/00—Fixed transformers or mutual inductances of the signal type
    • H01F19/04—Transformers or mutual inductances suitable for handling frequencies considerably beyond the audio range
    • H01F19/08—Transformers having magnetic bias, e.g. for handling pulses
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/52—Arrangements for conducting electric current within the device in operation from one component to another, i.e. interconnections, e.g. wires, lead frames
    • H01L23/522—Arrangements for conducting electric current within the device in operation from one component to another, i.e. interconnections, e.g. wires, lead frames including external interconnections consisting of a multilayer structure of conductive and insulating layers inseparably formed on the semiconductor body
    • H01L23/5227—Inductive arrangements or effects of, or between, wiring layers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F19/00—Fixed transformers or mutual inductances of the signal type
    • H01F19/04—Transformers or mutual inductances suitable for handling frequencies considerably beyond the audio range
    • H01F19/08—Transformers having magnetic bias, e.g. for handling pulses
    • H01F2019/085—Transformer for galvanic isolation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/0001—Technical content checked by a classifier
    • H01L2924/0002—Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Definitions

  • the present invention relates to a signal transmission insulating device and a power semiconductor module including the same.
  • a first coil is formed by forming a lower coil at the bottom of a recess provided in a semiconductor substrate, filling the recess with liquid polyimide resin, and curing it.
  • a device is known in which an upper coil is formed thereon and the thickness of the first insulating film is adjusted to ensure a dielectric strength voltage between the lower coil and the upper coil (for example, Patent Documents). 1).
  • a signal transmission insulating device having such a thin film transformer structure when a voltage is applied to the upper coil and the lower coil, electric field concentration occurs at the corners of the upper coil and the lower coil.
  • a signal transmission insulating device having a transformer structure has a plurality of corners, and when the applied voltage increases, dielectric breakdown occurs from either corner of the upper coil or the lower coil.
  • a second insulating film having a higher dielectric constant than the first insulating film is provided on the surface of the lower coil facing the upper coil, and the second insulating film is provided on the second insulating film.
  • a second insulating film having a higher dielectric constant than the first insulating film is formed on the lower coil on the lower coil side between the lower coil and the upper coil. Since they are formed in contact with each other, the electric field in the second insulating film is reduced, and the electric field concentration at the corners of the lower coil in contact with the second insulating film can be reduced.
  • the thickness of the insulating film must be increased more than necessary in consideration of electric field concentration at the corners of the upper coil.
  • the thickness of the insulating film is increased, the distance between the upper coil and the lower coil becomes longer, resulting in a problem that transmission characteristics such as signal transmission speed and transmission strength deteriorate.
  • the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a signal transmission insulating device capable of suppressing a decrease in signal transmission characteristics and improving a withstand voltage.
  • a signal transmission insulating device is provided between a first coil, a second coil facing the first coil and constituting a transformer together with the first coil, and the first coil and the second coil facing each other.
  • a first insulating film made of one dielectric, a first main surface facing the second coil of the first coil, and a second main surface facing the first coil of the first insulating film;
  • a second insulating film made of a second dielectric material having a dielectric constant higher than that of the first dielectric film, and a surface of the second coil facing the first coil and a surface of the first insulating film facing the second coil.
  • a third insulating film made of a third dielectric having a dielectric constant higher than that of the first dielectric.
  • the second insulating film, the first insulating film, and the third insulating film are sequentially formed between the first coil that is the lower coil and the second coil that is the upper coil.
  • the dielectric constants of the second insulating film and the third insulating film are higher than the dielectric constant of the first insulating film, the electric field in the second insulating film and the third insulating film is reduced. Therefore, the electric field concentration at the corners of the lower coil in contact with the second insulating film and the corners of the upper coil in contact with the third insulating film can be reduced. Accordingly, since the withstand voltage can be improved without increasing the thickness of the first insulating film, it is possible to improve the withstand voltage and to suppress a decrease in signal transmission characteristics.
  • FIG. 1 is a plan view showing the configuration of the signal transmission insulating device 1a according to the first embodiment of the present invention.
  • FIG. 2 is a cross-sectional view showing the configuration of the signal transmission insulating device 1a according to the first exemplary embodiment of the present invention.
  • FIG. 2 corresponds to a cross-sectional view taken along the line AA in FIG.
  • the signal transmission insulating device 1 a includes a coil-shaped first coil 4 and a second coil 5 in which wiring is wound around a plurality of turns, and the first coil 4 and the second coil 5 face each other. Configure the transformer. In FIG. 1, the portion of the first coil 4 that overlaps the second coil 5 is not shown.
  • the signal transmission insulating device 1a has a structure in which a so-called thin film transformer structure 9 is formed on a semiconductor substrate 2 made of Si or the like.
  • the thin film transformer structure 9 includes a lower insulating film 15, a first coil 4, a second insulating film 6 a, a first insulating film 3, a third insulating film 7, a second coil 5, and an upper insulating film 16.
  • a lower insulating film 15 is formed on the semiconductor substrate 2, and the first coil 4, which is a lower coil, is buried in the lower insulating film 15. However, the first main surface which is the upper surface of the first coil 4 is not buried in the lower insulating film 15.
  • a second insulating film 6 a is formed on the first coil 4 so as to cover the first main surface of the first coil 4. Further, a third insulating film 7 is formed on the second insulating film 6 a via the first insulating film 3, and the second coil 5 and the upper insulating film 16 are formed on the third insulating film 7. ing.
  • the first insulating film 3, the lower insulating film 15, and the upper insulating film 16 are insulating films made of SiO 2 (silicon oxide) film
  • the second insulating film 6a and the third insulating film 7 are made of SiO 2 .
  • the first coil 4 and the second coil 5 are formed so as to face each other, and the second insulating film 6a is formed so as to cover the first main surface of the first coil 4 facing the second coil 5.
  • the second insulating surface of the second coil 5 facing the first coil 4 is also formed so as to cover the third insulating film.
  • the second insulating film 6 a is in contact with all the coil portions on different circumferences of the first coil 4, and the third insulating film 7 is also in contact with all the coil portions on different circumferences of the second coil 5.
  • SiO 2 is used for the first insulating film 3, the lower insulating film 15, and the upper insulating film 16.
  • the present invention is not limited to this, and the first insulating film 3,
  • Other materials such as polyimide may be used for the lower insulating film 15 and the upper insulating film 16, and the same material or different materials may be used.
  • SiN is used for the second insulating film 6 a and the third insulating film 7, but the second insulating film 6 a and the third insulating film 7 have a dielectric constant higher than that of the dielectric used for the first insulating film 3.
  • Other high insulating materials may be used, and the second insulating film 6a and the third insulating film 7 may be made of the same material or different materials.
  • FIG. 3 is a sectional view showing a manufacturing flow of the signal transmission insulating device 1a according to the first embodiment of the present invention.
  • an insulating film 17 to be a lower insulating film 15 made of SiO 2 is formed on a semiconductor substrate 2 made of Si or the like by a CVD (Chemical Vapor Deposition) method. Then, a metal film 8a such as aluminum is formed on the insulating film 17 which becomes a part of the lower insulating film 15 by sputtering deposition.
  • CVD Chemical Vapor Deposition
  • the first coil 4 is formed by etching the metal film 8a. Then, an insulating film 17 made of SiO 2 is formed between the adjacent coil portions of the first coil 4 and on the surface of the first coil 4 facing the second coil 5 using the CVD method. To be buried. After that, the insulating film 17 protruding from the surface of the first coil 4 facing the second coil 5 to the second coil 5 side is polished by CMP (Chemical Mechanical Polish) method, and next to the first coil 4. The upper surface of the insulating film 17 formed between the perimeters is flush with the upper surface of the first coil 4. Thus, the lower insulating film 15 shown in FIG. 2 is formed. Thereby, a flat film can be formed on the lower insulating film 15 and the first coil 4.
  • CMP Chemical Mechanical Polish
  • a second insulating film 6a made of SiN is formed by a CVD method. Then, the first insulating film 3 made of SiO 2 is formed on the second insulating film 6a. Further, a third insulating film 7 is formed on the first insulating film 3. Thereafter, a metal film 8b is formed on the third insulating film 7 by sputtering deposition.
  • the second coil 5 is formed by etching the metal film 8b. Then, the upper insulating film 16 is formed between adjacent coil portions of the second coil 5 and on the upper surface of the second coil 5. Through the above steps, the signal transmission insulating device 1a shown in FIG. 2 can be obtained.
  • the signal transmission insulating device 1a having the thin film transformer structure 9 when a potential difference is generated between the first coil 4 and the second coil 5 due to the above configuration.
  • electric field concentration occurs at a plurality of corners of the first coil 4 and the second coil 5, but the first insulating film 3 having a different dielectric constant between the first coil 4 and the second coil 5, Since the second insulating film 6a and the third insulating film 7 are formed, the electric field inside the second insulating film 6a and the third insulating film 7 having a dielectric constant higher than that of the first insulating film 3 is relaxed.
  • the electric field concentration at the corner portion is reduced. Alleviated.
  • the distance between the first coil 4 and the second coil 5 can be reduced without increasing the thickness of the insulating film.
  • the withstand voltage can be improved without increasing the length. Therefore, it is possible to improve the withstand voltage and to suppress a decrease in transmission characteristics such as signal transmission speed and transmission intensity.
  • the second insulating film 6a and the third insulating film 7 are provided symmetrically on the entire lower surface side and upper surface side of the first insulating film 3, such as warpage of the first insulating film 3 and the like. Deformation can be effectively suppressed.
  • each insulating film so that the stresses generated by 6a and the third insulating film cancel each other. Thereby, since the stress which generate
  • the stress generated in each insulating film is determined by complex conditions such as the temperature at which the insulating film is formed, the gas flow rate, and the film thickness of the insulating film. What is necessary is just to adjust and manufacture these conditions.
  • the first insulating film 3 may be formed so that tensile stress is generated, and the second insulating film 6a and the third insulating film 7 may be compressed.
  • the metal film 8a and the metal film 8b are formed by sputtering deposition, respectively.
  • the present invention is not limited to this, and is formed by using thermal deposition, electron beam deposition, or the like. It is good as well.
  • the semiconductor substrate 2 is not limited to Si, but may be another semiconductor substrate such as SiC, and the metal film 8a and the metal film 8b are not limited to aluminum, and other materials such as Cu are used. be able to.
  • the signal transmission insulating device 1a according to the first embodiment of the present invention can be used for a power semiconductor module such as IPM (Intelligent Power Module).
  • IPM Intelligent Power Module
  • FIG. 4 is a block diagram showing a motor driving apparatus 100 using the power semiconductor module 50 including the signal transmission insulating device 1a according to Embodiment 1 of the present invention.
  • the motor driving device 100 includes a power semiconductor module 50 and a motor 30, and can drive the motor 30 by appropriately converting power output from a driving power source (not shown) by the power semiconductor module 50. .
  • the power semiconductor module 50 includes a control unit 10 (also referred to as “control circuit”), a signal transmission insulating device 1a, a drive circuit 11, a power semiconductor device 21, and a sensor 22.
  • the drive circuit 11 operates in accordance with a control signal 12 input from the control unit 10 via the signal transmission insulating device 1 a and outputs a drive signal 13 to the power semiconductor device 21.
  • the power semiconductor device 21 is a semiconductor device such as an IGBT or a MOSFET, and performs a switching operation based on the drive signal 13.
  • the sensor 22 measures the chip temperature of the power semiconductor device 21 and the flowing current, and outputs the sensor signal 14 to the drive circuit 11 and the control unit 10.
  • the control unit 10 outputs a control signal 12 to the drive circuit 11 based on the sensor signal 14 or the like input from the sensor 22 via the signal transmission insulating device 1a, and controls the power semiconductor device 21. And the control part 10 controls operation
  • the drive circuit 11 moves to the power semiconductor device 21.
  • the output of the drive signal 13 is stopped, and the power semiconductor device 21 is protected.
  • the power semiconductor device 21 can be protected by the drive circuit 11 and the sensor 22 provided in the power semiconductor module 50. Therefore, the power semiconductor module 50 has a protection function. Functionalized.
  • the control unit 10 since a signal with a relatively low voltage flows in the motor drive device 100 on the control unit 10 side, the control unit 10 has a low potential in the motor drive device 100.
  • a relatively high voltage signal flows in the motor drive device 100, and thus the main circuit of the inverter circuit such as the drive circuit 11 and the power semiconductor device 21. Is at a high potential in the motor driving apparatus 100.
  • a potential difference of several hundreds to thousands of volts is generated between the control unit 10 and the main circuit of the inverter circuit such as the drive circuit 11 or the power semiconductor device 21, and the drive circuit 11 or the power semiconductor is generated by this potential difference.
  • the elements of the control unit 10 may be destroyed.
  • control unit 10 and the drive circuit 11 are transmitted by transmitting signals between the control unit 10 and the drive circuit 11 or an inverter circuit such as the power semiconductor device 21 via the signal transmission insulating device 1a.
  • an inverter circuit such as the power semiconductor device 21
  • the signal transmission insulating device 1a can improve the withstand voltage and suppress the deterioration of signal transmission characteristics, when the predetermined withstand voltage is set, the signal transmission insulating device 1a
  • the transmission characteristics such as signal transmission speed and transmission intensity are higher than those of the signal transmission insulation device. Therefore, by applying the signal transmission insulating device 1a according to the first embodiment to the power semiconductor module 50, the insulation between the control unit 10 and the main circuit of the inverter circuit such as the drive circuit 11 or the power semiconductor device 21 is provided.
  • the transmission characteristics of the control signal 12 and the sensor signal 14 can be improved.
  • the power semiconductor device 21 can be operated at higher speed.
  • the power semiconductor module 50 becomes a power semiconductor module capable of high-speed response without impairing safety against dielectric breakdown. That is, the power semiconductor module has high quality and high safety.
  • the power semiconductor module 50 having the protection function is provided by providing the sensor 22 in the power semiconductor module 50.
  • the present invention is not limited to this.
  • a power semiconductor module which does not have may be used. Even in such a case, the power semiconductor module can be provided with the signal transmission insulating device 1a to insulate the drive circuit from the control unit and improve the transmission characteristics of the control signal 12 and the like, and can operate at high speed. It becomes.
  • FIG. The configuration of the present invention is not limited to the configuration of the signal transmission insulating device 1a according to the first embodiment, and may be other configurations. Therefore, a configuration different from the signal transmission insulating device 1a according to the first embodiment will be described. In the following, the second insulating film 6a that is different from the first embodiment of the present invention will be described, and description of other parts that are the same or corresponding will be omitted.
  • FIG. 5 is a sectional view showing a configuration of the signal transmission insulating device 1b according to the second exemplary embodiment of the present invention.
  • the same reference numerals as those in FIG. 2 denote the same or corresponding components, and the description thereof is omitted.
  • the signal transmission insulating device 1b according to the second embodiment is different from the signal transmission insulating device 1a according to the first embodiment in the configuration of the second insulating film 6a and the second insulating film 6b.
  • the second insulating film 6b is in contact with the first main surface facing the second coil 5 of the first coil 4 and is formed on the coil portions of different circumferences of the first coil 4 so as to be in contact with the side surface perpendicular to the first main surface. It is also provided in between.
  • FIG. 6 is a cross-sectional view showing a manufacturing flow of the signal transmission insulating device 1b according to the first exemplary embodiment of the present invention.
  • a lower insulating film 15 is formed on the semiconductor substrate 2 made of Si or the like by a CVD method. Then, a metal film 8a such as aluminum is formed on the lower insulating film 15 by sputtering deposition.
  • the first coil 4 is formed by etching the metal film 8a. Then, a second insulating film 6b is formed by a CVD method on each of the adjacent peripheral coil portions of the first coil 4 and on the surface of the first coil 4 facing the second coil 5.
  • the first insulating film 3 is formed on the second insulating film 6b by the CVD method. Then, the first insulating film 3 is polished to be flush with the CMP method. Further, a third insulating film 7 is formed on the first insulating film 3. Thereafter, a metal film 8b is formed on the third insulating film 7 by sputtering deposition.
  • the second coil 5 is formed by etching the metal film 8b. Then, the upper insulating film 16 is formed between adjacent coil portions of the second coil 5 and on the upper surface of the second coil 5.
  • the signal transmission insulation device 1b shown in FIG. 5 can be obtained by performing the above-described ten steps.
  • the configuration as described above is different between the first coil 4 and the second coil 5 when a potential difference is generated between the first coil 4 and the second coil 5. Since the first dielectric film 3, the second dielectric film 6b, and the third dielectric film 7 having a dielectric constant are formed, the electric field concentration at the corners of the first coil 4 and the second coil 5 is alleviated. As a result, the withstand voltage can be improved without increasing the thickness of the insulating film, that is, without increasing the distance between the first coil 4 and the second coil 5. It is possible to suppress a decrease in transmission characteristics such as transmission speed and transmission intensity.
  • the manufacture of the portion including the lower insulating film 15, the first coil 4, and the second insulating film 6b is simplified.
  • the number of processes can be reduced, and the production cost can be reduced.
  • the signal transmission insulating device 1b according to the second embodiment to a power semiconductor module, a high-quality and highly safe power semiconductor module can be provided.
  • FIG. 7 is sectional drawing which shows the structure of the signal transmission insulation device 1c concerning Embodiment 3 of this invention. 7, the same reference numerals as those in FIG. 2 denote the same or corresponding configurations.
  • the present embodiment differs from the first embodiment in the configuration of the second insulating film 6a and the third insulating film 7. Therefore, only the difference will be described below, and other configurations will be described. Will not be described.
  • the second insulating film 6 a and the third insulating film 7 are made of a dielectric having a resistivity lower than that of the dielectric used for the first insulating film 3.
  • the resistivity of a general SiO 2 film is 1 ⁇ 10 13 ⁇ m, and thus a SiN film is used as the second insulating film 6 a and the third insulating film 7.
  • a SiN film is used as the second insulating film 6 a and the third insulating film 7.
  • the combination of the first insulating film 3, the second insulating film 6a, and the third insulating film 7 is not limited to the SiO 2 film and the SiN film, but is used for the second insulating film 6a and the third insulating film 7.
  • the dielectric can be appropriately selected from dielectrics such as SiO 2 , SiN, and polyimide so that the dielectric has a combination having a lower resistivity than the dielectric used for the first insulating film 3.
  • the method for manufacturing the signal transmission insulating device 1c according to the third embodiment of the present invention is the same as the method for manufacturing the signal transmission insulating device 1a according to the first embodiment.
  • the configuration as described above is different between the first coil 4 and the second coil 5 when a potential difference occurs between the first coil 4 and the second coil 5. Since the first insulating film 3, the second insulating film 6 b, and the third insulating film 7 having the resistivity are formed, the electric field concentration at the corners of the first coil 4 and the second coil 5 is alleviated. As a result, the withstand voltage can be improved without increasing the thickness of the insulating film, that is, without increasing the distance between the first coil 4 and the second coil 5. It is possible to suppress a decrease in transmission characteristics such as transmission speed and transmission intensity.
  • the second insulating film 6a and the third insulating film 7 have a resistivity equal to or higher than a resistivity that does not cause an electrical short circuit between adjacent coils of the first coil 4 or between adjacent coils of the second coil 5.
  • FIG. 8 shows operation waveforms of the signal transmission insulating device 1c according to the third embodiment.
  • 8A shows an input rectangular wave electric signal
  • FIG. 8B shows an output pulse electric signal.
  • the vertical axis represents the voltage of each signal
  • the horizontal axis represents time.
  • a rectangular wave electric signal V in respect one of the first coil 4 and second coil 5 is input, the rising of the input square wave electrical signal V in Corresponding to the falling, a pulse electric signal Vout having a frequency F is output to the other coil.
  • T / 2 shown in FIG.
  • the time constant ⁇ between adjacent coils needs to satisfy the formula (1).
  • the time constant ⁇ is obtained by the equation (2) using the resistivity ⁇ , the relative dielectric constant ⁇ r , and the vacuum dielectric constant ⁇ 0 .
  • the second insulating film 6a and the third insulating film 7 are SiN films, if ⁇ r of the SiN film is 7 and ⁇ 0 is 8.85 ⁇ 10 ⁇ 12 F / m, the equations (1) and (2)
  • the resistivity of the second insulating film 6a and the third insulating film 7 must be greater than 16 ⁇ m. Therefore, a SiN film having a resistivity larger than 16 ⁇ m may be selected.
  • the signal transmission insulating device 1c according to the second embodiment to a power semiconductor module, a high-quality and highly safe power semiconductor module can be provided.
  • FIG. 9 is sectional drawing which shows the structure of the signal transmission insulation device 1d concerning Embodiment 4 of this invention.
  • the same reference numerals as those in FIG. 5 denote the same or corresponding configurations.
  • the present embodiment differs from the second embodiment in the configuration of the second insulating film 6b and the third insulating film 7, so that only the difference will be described below and other configurations will be described. Will not be described.
  • the second insulating film 6 b and the third insulating film 7 are made of a dielectric having a resistivity lower than that of the dielectric used for the first insulating film 3.
  • the resistivity of a general SiO 2 film is 1 ⁇ 10 13 ⁇ m, and thus a SiN film as the second insulating film 6 b and the third insulating film 7. Can be used.
  • the combination of the first insulating film 3, the second insulating film 6b, and the third insulating film 7 is not limited to the SiO 2 film and the SiN film, but is used for the second insulating film 6b and the third insulating film 7.
  • the dielectric can be appropriately selected from dielectrics such as SiO 2 , SiN, and polyimide so that the dielectric has a combination having a lower resistivity than the dielectric used for the first insulating film 3.
  • the frequency F of the output pulse electric signal Vout is 1 GHz
  • the SiO 2 film is used as the first insulating film 3
  • the second insulating film 6b and the third insulating film 7 are used.
  • the resistivity should be larger than 16 ⁇ m.
  • the manufacturing method of the signal transmission insulating device 1d according to the fourth embodiment of the present invention is the same as the manufacturing method of the signal transmission insulating device 1b according to the second embodiment.
  • the configuration as described above is different between the first coil 4 and the second coil 5 when a potential difference is generated between the first coil 4 and the second coil 5. Since the first insulating film 3, the second insulating film 6 b, and the third insulating film 7 having the resistivity are formed, the electric field concentration at the corners of the first coil 4 and the second coil 5 is alleviated. As a result, the withstand voltage can be improved without increasing the thickness of the insulating film, that is, without increasing the distance between the first coil 4 and the second coil 5. It is possible to suppress a decrease in transmission characteristics such as transmission speed and transmission intensity.
  • the manufacturing of the portion including the lower insulating film 15, the first coil 4, and the second insulating film 6b is simplified.
  • the number of processes during manufacturing can be reduced, and the production cost can be reduced.
  • the embodiments can be freely combined within the scope of the invention, and the embodiments can be appropriately modified or omitted.
  • 1a 1b 1c 1d signal transmission insulation device 2 semiconductor substrate, 3 first insulating film, 4 first coil, 5 second coil, 6a 6b second insulating film, 7 third insulating film, 8a 8b metal film, 9 Thin-film transformer structure, 10 control unit, 11 drive circuit, 12 control signal, 13 drive signal, 14 sensor signal, 15 lower insulating film, 16 upper insulating film, 17 insulating film, 21 power semiconductor devices, 22 sensors, 30 motors, 50 power semiconductor module, 100 motor drive device.

Abstract

The present invention pertains to a signal transmission insulation device provided with the following: a first coil; a second coil that faces the first coil and constitutes a transformer along with the first coil; a first insulating film that is provided in a space where the first coil and second coil are opposed, and that comprises a first dielectric; a second insulating film that is provided between a first primary surface of the first coil opposing the second coil and a surface of the first insulating film opposing the first coil, and that comprises a second dielectric having a higher dielectric constant than the first dielectric; and a third insulating film that is provided between a surface of the second coil opposing the first coil and a surface of the first insulating film opposing the second coil, and that comprises a third dielectric having a higher dielectric constant than the first dielectric.

Description

信号伝送絶縁デバイス及びパワー半導体モジュールSignal transmission isolation device and power semiconductor module
　本発明は、信号伝送絶縁デバイス及びこれを備えたパワー半導体モジュールに関するものである。 The present invention relates to a signal transmission insulating device and a power semiconductor module including the same.
　従来の薄膜トランス構造を有する信号伝送絶縁デバイスにおいては、半導体基板に設けた凹部の底部に下側コイルを形成し、液状のポリイミド樹脂で凹部を充填し硬化させることで第１絶縁膜を形成して、その上に上側コイルを形成し、第１絶縁膜の厚さを調整することで、下側コイルと上側コイルとの間の絶縁耐圧を確保するものが知られている（例えば、特許文献１参照）。 In a signal transmission insulating device having a conventional thin film transformer structure, a first coil is formed by forming a lower coil at the bottom of a recess provided in a semiconductor substrate, filling the recess with liquid polyimide resin, and curing it. In addition, a device is known in which an upper coil is formed thereon and the thickness of the first insulating film is adjusted to ensure a dielectric strength voltage between the lower coil and the upper coil (for example, Patent Documents). 1).
　このような薄膜トランス構造を有する信号伝送絶縁デバイスでは、上側コイル及び下側コイルに電圧が印加された場合、上側コイル及び下側コイルそれぞれの角部において電界集中が発生する。そして、トランス構造を有する信号伝送絶縁デバイスでは複数の角部があり、印加される電圧が大きくなると上側コイル又は下側コイルのいずれかの角部から絶縁破壊が生じる。一方、特許文献２に記載された信号伝送絶縁デバイスのように、下側コイルの上側コイルに対向する面上に第１絶縁膜よりも誘電率の高い第２絶縁膜を設け、その上に第１絶縁膜及び上側コイルを順次形成した信号伝送絶縁デバイスでは、下側コイルと上側コイルとの間の下側コイル側に第１絶縁膜よりも誘電率の高い第２絶縁膜が下側コイルに接して形成されているため、第２絶縁膜内での電界が小さくなり、第２絶縁膜に接する下側コイルの角部での電界集中を緩和することができる。 In the signal transmission insulating device having such a thin film transformer structure, when a voltage is applied to the upper coil and the lower coil, electric field concentration occurs at the corners of the upper coil and the lower coil. A signal transmission insulating device having a transformer structure has a plurality of corners, and when the applied voltage increases, dielectric breakdown occurs from either corner of the upper coil or the lower coil. On the other hand, like the signal transmission insulating device described in Patent Document 2, a second insulating film having a higher dielectric constant than the first insulating film is provided on the surface of the lower coil facing the upper coil, and the second insulating film is provided on the second insulating film. In a signal transmission insulating device in which an insulating film and an upper coil are sequentially formed, a second insulating film having a higher dielectric constant than the first insulating film is formed on the lower coil on the lower coil side between the lower coil and the upper coil. Since they are formed in contact with each other, the electric field in the second insulating film is reduced, and the electric field concentration at the corners of the lower coil in contact with the second insulating film can be reduced.
特開２００７－１６５３４３号公報JP 2007-165343 A 特開２０１０－８０７７４号公報JP 2010-80774 A
　しかしながら、上述の第２絶縁膜を有する信号伝送絶縁デバイスであっても、薄膜トランス構造の上下コイルに電圧が印加された場合、下側コイルの角部における電界集中は緩和されるものの、上側コイルの角部においては依然として電界集中が発生する。ところで、絶縁破壊は電界が集中する最も絶縁が弱い箇所が起点となって開始することが通常である。従って、印加される電圧が大きくなると、電界が集中する絶縁の弱点箇所である上側コイルの角部から絶縁破壊が生じてしまい、絶縁耐圧を向上させることが困難となっていた。そのため、所定の耐圧を確保するためには、上側コイルの角部における電界集中を考慮して必要以上に絶縁膜の厚みを厚くしなくてはならない。しかし、絶縁膜の厚みを厚くしてしまうと、上側コイルと下側コイルとの間の距離が長くなり、信号の伝送速度や伝送強度といった伝送特性が低下するという問題が生じていた。 However, even in the signal transmission insulating device having the second insulating film described above, when voltage is applied to the upper and lower coils of the thin film transformer structure, the electric field concentration at the corners of the lower coil is reduced, but the upper coil Electric field concentration still occurs at the corners. By the way, it is normal that the dielectric breakdown starts from the place where the insulation is weakest where the electric field is concentrated. Therefore, when the applied voltage is increased, dielectric breakdown occurs from the corner portion of the upper coil, which is a weak point of insulation where the electric field concentrates, and it is difficult to improve the withstand voltage. Therefore, in order to ensure a predetermined breakdown voltage, the thickness of the insulating film must be increased more than necessary in consideration of electric field concentration at the corners of the upper coil. However, if the thickness of the insulating film is increased, the distance between the upper coil and the lower coil becomes longer, resulting in a problem that transmission characteristics such as signal transmission speed and transmission strength deteriorate.
　本発明は、上述のような問題を解決するためになされたもので、信号の伝送特性の低下を抑制するとともに耐圧を向上させることができる信号伝送絶縁デバイスを提供することを目的とする。 The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a signal transmission insulating device capable of suppressing a decrease in signal transmission characteristics and improving a withstand voltage.
　本発明にかかる信号伝送絶縁デバイスは、第１コイルと、第１コイルに対向し第１コイルとともにトランスを構成する第２コイルと、第１コイルと第２コイルとが対向する間に設けられ第１の誘電体からなる第１絶縁膜と、第１コイルの第２コイルに対向する第一主面と第１絶縁膜の第１コイルに対向する第二主面との間に設けられ第１の誘電体よりも誘電率が高い第２の誘電体からなる第２絶縁膜と、第２コイルの第１コイルに対向する面と第１絶縁膜の第２コイルに対向する面との間に設けられ第１の誘電体よりも誘電率が高い第３の誘電体からなる第３絶縁膜とを備えたものである。 A signal transmission insulating device according to the present invention is provided between a first coil, a second coil facing the first coil and constituting a transformer together with the first coil, and the first coil and the second coil facing each other. A first insulating film made of one dielectric, a first main surface facing the second coil of the first coil, and a second main surface facing the first coil of the first insulating film; A second insulating film made of a second dielectric material having a dielectric constant higher than that of the first dielectric film, and a surface of the second coil facing the first coil and a surface of the first insulating film facing the second coil. And a third insulating film made of a third dielectric having a dielectric constant higher than that of the first dielectric.
　本発明にかかる信号伝送絶縁デバイスによれば、下側コイルである第１コイルと上側コイルである第２コイルとの間に第２絶縁膜、第１絶縁膜及び第３絶縁膜が順に形成されており、かつ第２絶縁膜及び第３絶縁膜の誘電率は第１絶縁膜の誘電率よりも高いので、第２絶縁膜及び第３絶縁膜内での電界が小さくなる。そのため、第２絶縁膜に接する下側コイルの角部及び第３絶縁膜に接する上側コイルの角部での電界集中を緩和することができる。よって、第１絶縁膜の厚みを厚くすることなく絶縁耐圧を向上させることができるため、絶縁耐圧を向上させるとともに信号の伝送特性の低下を抑制することができる。 According to the signal transmission insulating device of the present invention, the second insulating film, the first insulating film, and the third insulating film are sequentially formed between the first coil that is the lower coil and the second coil that is the upper coil. In addition, since the dielectric constants of the second insulating film and the third insulating film are higher than the dielectric constant of the first insulating film, the electric field in the second insulating film and the third insulating film is reduced. Therefore, the electric field concentration at the corners of the lower coil in contact with the second insulating film and the corners of the upper coil in contact with the third insulating film can be reduced. Accordingly, since the withstand voltage can be improved without increasing the thickness of the first insulating film, it is possible to improve the withstand voltage and to suppress a decrease in signal transmission characteristics.
本発明の実施の形態１にかかる信号伝送絶縁デバイスの構成を示す平面図である。It is a top view which shows the structure of the signal-transmission insulation device concerning Embodiment 1 of this invention. 本発明の実施の形態１にかかる信号伝送絶縁デバイスの構成を示す断面図である。It is sectional drawing which shows the structure of the signal-transmission insulation device concerning Embodiment 1 of this invention. 本発明の実施の形態１にかかる信号伝送絶縁デバイスの製造フローを示す断面図である。It is sectional drawing which shows the manufacture flow of the signal-transmission insulation device concerning Embodiment 1 of this invention. 本発明の実施の形態１に係る信号伝送絶縁デバイスを備えたパワー半導体モジュールを用いたモータ駆動装置を示すブロック図である。It is a block diagram which shows the motor drive device using the power semiconductor module provided with the signal transmission insulation device which concerns on Embodiment 1 of this invention. 本発明の実施の形態２にかかる信号伝送絶縁デバイスの構造を示す断面図である。It is sectional drawing which shows the structure of the signal-transmission insulation device concerning Embodiment 2 of this invention. 本発明の実施の形態２にかかる信号伝送絶縁デバイスの製造フローを示す断面図である。It is sectional drawing which shows the manufacture flow of the signal-transmission insulation device concerning Embodiment 2 of this invention. 本発明の実施の形態３にかかる信号伝送絶縁デバイスの構造を示す断面図である。It is sectional drawing which shows the structure of the signal-transmission insulation device concerning Embodiment 3 of this invention. 本発明の実施の形態３にかかる信号伝送絶縁デバイスの動作波形を示す波形図である。It is a wave form diagram which shows the operation | movement waveform of the signal-transmission insulation device concerning Embodiment 3 of this invention. 本発明の実施の形態４にかかる信号伝送絶縁デバイスの構造を示す断面図である。It is sectional drawing which shows the structure of the signal-transmission insulation device concerning Embodiment 4 of this invention.
実施の形態１．
　まず、本発明の実施の形態１にかかる信号伝送絶縁デバイスの構成について説明する。図１は、本発明の実施の形態１にかかる信号伝送絶縁デバイス１ａの構成を示す平面図である。図２は、本発明の実施の形態１にかかる信号伝送絶縁デバイス１ａの構成を示す断面図である。なお、図２は、図１におけるＡ－Ａ断面図に相当するものである。 Embodiment 1 FIG.
First, the configuration of the signal transmission insulating device according to the first exemplary embodiment of the present invention will be described. FIG. 1 is a plan view showing the configuration of the signal transmission insulating device 1a according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view showing the configuration of the signal transmission insulating device 1a according to the first exemplary embodiment of the present invention. FIG. 2 corresponds to a cross-sectional view taken along the line AA in FIG.
　図１において、信号伝送絶縁デバイス１ａは、配線が複数周巻き回されたコイル形状の第１コイル４と第２コイル５を備えており、第１コイル４と第２コイル５とは互いに対向しトランスを構成する。なお、図１において、第１コイル４の第２コイル５に重なっている部分については図示省略している。 In FIG. 1, the signal transmission insulating device 1 a includes a coil-shaped first coil 4 and a second coil 5 in which wiring is wound around a plurality of turns, and the first coil 4 and the second coil 5 face each other. Configure the transformer. In FIG. 1, the portion of the first coil 4 that overlaps the second coil 5 is not shown.
　図２において、信号伝送絶縁デバイス１ａは、Ｓｉ等からなる半導体基板２上にいわゆる薄膜トランス構造９が形成された構造となっている。薄膜トランス構造９は、下側絶縁膜１５、第１コイル４、第２絶縁膜６ａ、第１絶縁膜３、第３絶縁膜７、第２コイル５、及び上側絶縁膜１６から構成されている。半導体基板２の上には、下側絶縁膜１５が形成されており、下側絶縁膜１５に下側コイルである第１コイル４が埋もれるように形成されている。ただし、第１コイル４の上側の面である第一主面は下側絶縁膜１５の中に埋もれていない。また、第１コイル４上には、第２絶縁膜６ａが第１コイル４の第一主面を覆うように形成されている。さらに、第２絶縁膜６ａ上には、第１絶縁膜３を介して第３絶縁膜７が形成されており、第３絶縁膜７上には第２コイル５及び上側絶縁膜１６が形成されている。 In FIG. 2, the signal transmission insulating device 1a has a structure in which a so-called thin film transformer structure 9 is formed on a semiconductor substrate 2 made of Si or the like. The thin film transformer structure 9 includes a lower insulating film 15, a first coil 4, a second insulating film 6 a, a first insulating film 3, a third insulating film 7, a second coil 5, and an upper insulating film 16. . A lower insulating film 15 is formed on the semiconductor substrate 2, and the first coil 4, which is a lower coil, is buried in the lower insulating film 15. However, the first main surface which is the upper surface of the first coil 4 is not buried in the lower insulating film 15. A second insulating film 6 a is formed on the first coil 4 so as to cover the first main surface of the first coil 4. Further, a third insulating film 7 is formed on the second insulating film 6 a via the first insulating film 3, and the second coil 5 and the upper insulating film 16 are formed on the third insulating film 7. ing.
　ここで、第１絶縁膜３、下側絶縁膜１５、及び上側絶縁膜１６はＳｉＯ２（酸化珪素）膜から成る絶縁膜であり、第２絶縁膜６ａ及び第３絶縁膜７はＳｉＯ２よりも誘電率の高いＳｉＮ（窒化珪素）膜から成る絶縁膜である。また、第１コイル４と第２コイル５は互いに対向するように形成されており、第１コイル４の第２コイル５に対向する第一主面を覆うように第２絶縁膜６ａが形成されているのと同様に、第２コイル５の第１コイル４に対向する第二主面についても第３絶縁膜が覆うように形成されている。さらに、第２絶縁膜６ａは第１コイル４の異なる周におけるコイル部分全てに接しており、第３絶縁膜７も同様に第２コイル５の異なる周におけるコイル部分全てに接している。 Here, the first insulating film 3, the lower insulating film 15, and the upper insulating film 16 are insulating films made of SiO 2 (silicon oxide) film, and the second insulating film 6a and the third insulating film 7 are made of SiO 2 . Is an insulating film made of a SiN (silicon nitride) film having a high dielectric constant. The first coil 4 and the second coil 5 are formed so as to face each other, and the second insulating film 6a is formed so as to cover the first main surface of the first coil 4 facing the second coil 5. In the same manner as described above, the second insulating surface of the second coil 5 facing the first coil 4 is also formed so as to cover the third insulating film. Further, the second insulating film 6 a is in contact with all the coil portions on different circumferences of the first coil 4, and the third insulating film 7 is also in contact with all the coil portions on different circumferences of the second coil 5.
　なお、本実施の形態では、第１絶縁膜３、下側絶縁膜１５、及び上側絶縁膜１６にＳｉＯ２を用いることとしているが、これに限定されるものではなく、第１絶縁膜３、下側絶縁膜１５、及び上側絶縁膜１６にはポリイミド等の他の材料を用いることとしてもよく、同一の材料であっても異なる材料であっても構わない。また、第２絶縁膜６ａ及び第３絶縁膜７にＳｉＮを用いることとしているが、第２絶縁膜６ａ及び第３絶縁膜７には第１絶縁膜３に用いた誘電体よりも誘電率の高い他の絶縁材料を用いることとすればよく、第２絶縁膜６ａ及び第３絶縁膜７は同一の材料であっても異なる材料であっても構わない。 In the present embodiment, SiO 2 is used for the first insulating film 3, the lower insulating film 15, and the upper insulating film 16. However, the present invention is not limited to this, and the first insulating film 3, Other materials such as polyimide may be used for the lower insulating film 15 and the upper insulating film 16, and the same material or different materials may be used. SiN is used for the second insulating film 6 a and the third insulating film 7, but the second insulating film 6 a and the third insulating film 7 have a dielectric constant higher than that of the dielectric used for the first insulating film 3. Other high insulating materials may be used, and the second insulating film 6a and the third insulating film 7 may be made of the same material or different materials.
　次に、本発明の実施の形態１にかかる信号伝送絶縁デバイス１ａの製造方法について説明する。図３は、本発明の実施の形態１にかかる信号伝送絶縁デバイス１ａの製造フローを示す断面図である。 Next, a method for manufacturing the signal transmission insulating device 1a according to the first embodiment of the present invention will be described. FIG. 3 is a sectional view showing a manufacturing flow of the signal transmission insulating device 1a according to the first embodiment of the present invention.
　図３（ａ）において、Ｓｉ等からなる半導体基板２上に、ＣＶＤ（Ｃｈｅｍｉｃａｌ　Ｖａｐｏｒ　Ｄｅｐｏｓｉｔｉｏｎ：化学気相法）法によりＳｉＯ２からなる下側絶縁膜１５となる絶縁膜１７を形成する。そして、この下側絶縁膜１５の一部となる絶縁膜１７上に、スパッタ蒸着法により、アルミニウムなどの金属膜８ａを形成する。 In FIG. 3A, an insulating film 17 to be a lower insulating film 15 made of SiO 2 is formed on a semiconductor substrate 2 made of Si or the like by a CVD (Chemical Vapor Deposition) method. Then, a metal film 8a such as aluminum is formed on the insulating film 17 which becomes a part of the lower insulating film 15 by sputtering deposition.
　図３（ｂ）において、金属膜８ａをエッチングして第１コイル４を形成する。そして、第１コイル４の隣り合う周のコイル部分それぞれの間と第１コイル４の第２コイル５に対向する面上に、ＣＶＤ法を用いてＳｉＯ２からなる絶縁膜１７を第１コイル４が埋もれるように形成する。その後、ＣＭＰ（Ｃｈｅｍｉｃｈａｌ　Ｍｅｃｈａｎｉｃａｌ　Ｐｏｌｉｓｈ：化学機械研磨）法により第１コイル４の第２コイル５に対向する面から第２コイル５側にはみ出している絶縁膜１７を研磨し、第１コイル４の隣り合う周の間に形成された絶縁膜１７の上面と第１コイル４の上面とを面一にする。以上により、図２に示された下側絶縁膜１５が形成される。これにより、下側絶縁膜１５と第１コイル４との上に平坦な膜を形成することができる。 In FIG. 3B, the first coil 4 is formed by etching the metal film 8a. Then, an insulating film 17 made of SiO 2 is formed between the adjacent coil portions of the first coil 4 and on the surface of the first coil 4 facing the second coil 5 using the CVD method. To be buried. After that, the insulating film 17 protruding from the surface of the first coil 4 facing the second coil 5 to the second coil 5 side is polished by CMP (Chemical Mechanical Polish) method, and next to the first coil 4. The upper surface of the insulating film 17 formed between the perimeters is flush with the upper surface of the first coil 4. Thus, the lower insulating film 15 shown in FIG. 2 is formed. Thereby, a flat film can be formed on the lower insulating film 15 and the first coil 4.
　図３（ｃ）において、ＣＶＤ法によりＳｉＮからなる第２絶縁膜６ａを形成する。そして、第２絶縁膜６ａ上にＳｉＯ２からなる第１絶縁膜３を形成する。さらに、第１絶縁膜３上に第３絶縁膜７を形成する。その後、第３絶縁膜７上に、スパッタ蒸着法により、金属膜８ｂを形成する。 In FIG. 3C, a second insulating film 6a made of SiN is formed by a CVD method. Then, the first insulating film 3 made of SiO 2 is formed on the second insulating film 6a. Further, a third insulating film 7 is formed on the first insulating film 3. Thereafter, a metal film 8b is formed on the third insulating film 7 by sputtering deposition.
　図３（ｄ）において、金属膜８ｂをエッチングして第２コイル５を形成する。そして、第２コイル５の隣接する周のコイル部分の間と第２コイル５の上面に上側絶縁膜１６を形成する。以上の工程により、図２に示した信号伝送絶縁デバイス１ａを得ることができる。 In FIG. 3D, the second coil 5 is formed by etching the metal film 8b. Then, the upper insulating film 16 is formed between adjacent coil portions of the second coil 5 and on the upper surface of the second coil 5. Through the above steps, the signal transmission insulating device 1a shown in FIG. 2 can be obtained.
　本発明の実施の形態１では、以上のような構成としたことにより、第１コイル４と第２コイル５との間に電位差が生じた場合に、薄膜トランス構造９を有する信号伝送絶縁デバイス１ａでは第１コイル４と第２コイル５の複数の角部において電界集中が発生することとなるが、第１コイル４と第２コイル５との間に異なる誘電率の第１絶縁膜３、第２絶縁膜６ａ、及び第３絶縁膜７が形成されているため、第１絶縁膜３よりも誘電率の高い第２絶縁膜６ａ及び第３絶縁膜７の内部の電界が緩和される。そして、電界集中が生じる第１コイル４及び第２コイル５それぞれの角部が、電界が緩和される第２絶縁膜６ａ及び第３絶縁膜７に接しているため、当該角部における電界集中が緩和される。その結果、第１コイル４及び第２コイル５側の双方での電界集中が緩和されるため、絶縁膜の厚さを厚くすることなく、すなわち第１コイル４と第２コイル５との距離を長くすることなく絶縁耐圧を向上させることができる。よって、絶縁耐圧を向上させるとともに信号の伝送速度や伝送強度といった伝送特性の低下を抑制することができる。 In the first embodiment of the present invention, the signal transmission insulating device 1a having the thin film transformer structure 9 when a potential difference is generated between the first coil 4 and the second coil 5 due to the above configuration. In this case, electric field concentration occurs at a plurality of corners of the first coil 4 and the second coil 5, but the first insulating film 3 having a different dielectric constant between the first coil 4 and the second coil 5, Since the second insulating film 6a and the third insulating film 7 are formed, the electric field inside the second insulating film 6a and the third insulating film 7 having a dielectric constant higher than that of the first insulating film 3 is relaxed. Since the corner portions of the first coil 4 and the second coil 5 where the electric field concentration occurs are in contact with the second insulating film 6a and the third insulating film 7 where the electric field is relaxed, the electric field concentration at the corner portion is reduced. Alleviated. As a result, since the electric field concentration on both the first coil 4 and the second coil 5 side is relaxed, the distance between the first coil 4 and the second coil 5 can be reduced without increasing the thickness of the insulating film. The withstand voltage can be improved without increasing the length. Therefore, it is possible to improve the withstand voltage and to suppress a decrease in transmission characteristics such as signal transmission speed and transmission intensity.
　また、第１絶縁膜３の下面側と上面側には、それぞれの全面に第２絶縁膜６ａと第３絶縁膜７とが対称に設けられているため、第１絶縁膜３の反り等の変形を効果的に抑制することができる。 Further, since the second insulating film 6a and the third insulating film 7 are provided symmetrically on the entire lower surface side and upper surface side of the first insulating film 3, such as warpage of the first insulating film 3 and the like. Deformation can be effectively suppressed.
　さらに、第１絶縁膜３では圧縮応力が発生し、第２絶縁膜６ａ及び第３絶縁膜７では引張応力が発生するように、すなわち、第１絶縁膜３で発生する応力と第２絶縁膜６ａ及び第３絶縁膜とで発生する応力とが打ち消し合うように、各絶縁膜を形成することが望ましい。これにより、各絶縁膜同士で発生する応力が打ち消し合うため、半導体基板２や各絶縁膜の反り変形を低減することができる。なお、各絶縁膜で発生する応力は絶縁膜を形成する際の温度やガスの流量、さらには絶縁膜の膜厚といった複合的な条件によって定まるため、膜を積層する際に応力を計測しながらこれらの条件を調整し製造すればよい。また、第１絶縁膜３では引張応力が発生し、第２絶縁膜６ａ及び第３絶縁膜７では圧縮応力が発生するように形成することとしてもよい。 Further, compressive stress is generated in the first insulating film 3, and tensile stress is generated in the second insulating film 6a and the third insulating film 7, that is, the stress generated in the first insulating film 3 and the second insulating film. It is desirable to form each insulating film so that the stresses generated by 6a and the third insulating film cancel each other. Thereby, since the stress which generate | occur | produces between each insulating film cancels, the curvature deformation of the semiconductor substrate 2 or each insulating film can be reduced. The stress generated in each insulating film is determined by complex conditions such as the temperature at which the insulating film is formed, the gas flow rate, and the film thickness of the insulating film. What is necessary is just to adjust and manufacture these conditions. The first insulating film 3 may be formed so that tensile stress is generated, and the second insulating film 6a and the third insulating film 7 may be compressed.
　なお、本実施の形態では金属膜８ａ及び金属膜８ｂをそれぞれスパッタ蒸着法により形成することとしたが、これに限定されるものではなく、熱蒸着法や電子ビーム蒸着法等を用いて形成することとしてもよい。また、半導体基板２はＳｉに限定されるものでなくＳｉＣ等の他の半導体基板でもよく、金属膜８ａ及び金属膜８ｂはいずれもアルミニウムに限定されるものではなくＣｕ等の他の材料を用いることができる。 In the present embodiment, the metal film 8a and the metal film 8b are formed by sputtering deposition, respectively. However, the present invention is not limited to this, and is formed by using thermal deposition, electron beam deposition, or the like. It is good as well. Further, the semiconductor substrate 2 is not limited to Si, but may be another semiconductor substrate such as SiC, and the metal film 8a and the metal film 8b are not limited to aluminum, and other materials such as Cu are used. be able to.
　また、本発明の実施の形態１にかかる信号伝送絶縁デバイス１ａは、ＩＰＭ（Ｉｎｔｅｌｌｉｇｅｎｔ　Ｐｏｗｅｒ　Ｍｏｄｕｌｅ）をはじめとするパワー半導体モジュールに用いることができる。以下、本発明の実施の形態１にかかる信号伝送絶縁デバイス１ａを備えたパワー半導体モジュールを、モータ駆動装置に用いた場合について説明する。図４は、本発明の実施の形態１に係る信号伝送絶縁デバイス１ａを備えたパワー半導体モジュール５０を用いたモータ駆動装置１００を示すブロック図である。 Further, the signal transmission insulating device 1a according to the first embodiment of the present invention can be used for a power semiconductor module such as IPM (Intelligent Power Module). Hereinafter, the case where the power semiconductor module provided with the signal transmission insulation device 1a concerning Embodiment 1 of this invention is used for a motor drive device is demonstrated. FIG. 4 is a block diagram showing a motor driving apparatus 100 using the power semiconductor module 50 including the signal transmission insulating device 1a according to Embodiment 1 of the present invention.
　図４において、モータ駆動装置１００は、パワー半導体モジュール５０及びモータ３０から構成され、図示しない駆動用電源から出力される電力をパワー半導体モジュール５０によって適宜変換することでモータ３０を駆動することができる。 In FIG. 4, the motor driving device 100 includes a power semiconductor module 50 and a motor 30, and can drive the motor 30 by appropriately converting power output from a driving power source (not shown) by the power semiconductor module 50. .
　パワー半導体モジュール５０は、制御部１０（「制御回路」ともいう。）、信号伝送絶縁デバイス１ａ、駆動回路１１、パワー半導体装置２１、及びセンサ２２から構成される。駆動回路１１は、制御部１０から信号伝送絶縁デバイス１ａを介して入力される制御信号１２によって動作し、パワー半導体装置２１に駆動信号１３を出力する。パワー半導体装置２１はＩＧＢＴやＭＯＳＦＥＴ等の半導体装置であり、駆動信号１３に基づいてスイッチング動作を行う。一方、センサ２２は、パワー半導体装置２１のチップ温度や通流する電流を計測し、センサ信号１４を駆動回路１１及び制御部１０に出力する。制御部１０は、センサ２２から信号伝送絶縁デバイス１ａを介して入力されるセンサ信号１４等に基づいて駆動回路１１に制御信号１２を出力し、パワー半導体装置２１を制御する。そして、制御部１０がパワー半導体装置２１の動作を制御することで、インバータ回路として所定の電力変換が行われモータ３０を駆動することができる。なお、制御部１０と駆動回路１１又はセンサ２２との信号の入出力は、パワー半導体モジュール５０に設けられた信号伝送絶縁デバイス１ａを介して行われる。 The power semiconductor module 50 includes a control unit 10 (also referred to as “control circuit”), a signal transmission insulating device 1a, a drive circuit 11, a power semiconductor device 21, and a sensor 22. The drive circuit 11 operates in accordance with a control signal 12 input from the control unit 10 via the signal transmission insulating device 1 a and outputs a drive signal 13 to the power semiconductor device 21. The power semiconductor device 21 is a semiconductor device such as an IGBT or a MOSFET, and performs a switching operation based on the drive signal 13. On the other hand, the sensor 22 measures the chip temperature of the power semiconductor device 21 and the flowing current, and outputs the sensor signal 14 to the drive circuit 11 and the control unit 10. The control unit 10 outputs a control signal 12 to the drive circuit 11 based on the sensor signal 14 or the like input from the sensor 22 via the signal transmission insulating device 1a, and controls the power semiconductor device 21. And the control part 10 controls operation | movement of the power semiconductor device 21, and predetermined | prescribed power conversion is performed as an inverter circuit and the motor 30 can be driven. In addition, input / output of signals between the control unit 10 and the drive circuit 11 or the sensor 22 is performed via a signal transmission insulating device 1 a provided in the power semiconductor module 50.
　また、センサ２２がパワー半導体装置２１への過電流を計測した場合やパワー半導体装置２１のチップ温度が所定の値以上に上昇したことを計測した場合には、駆動回路１１はパワー半導体装置２１への駆動信号１３の出力を停止し、パワー半導体装置２１を保護する。このような構成とすることで、パワー半導体モジュール５０に設けられた駆動回路１１及びセンサ２２によってパワー半導体装置２１を保護することが可能となるため、パワー半導体モジュール５０が保護機能を有することとなり高機能化される。 Further, when the sensor 22 measures an overcurrent to the power semiconductor device 21 or when the chip temperature of the power semiconductor device 21 is measured to be higher than a predetermined value, the drive circuit 11 moves to the power semiconductor device 21. The output of the drive signal 13 is stopped, and the power semiconductor device 21 is protected. By adopting such a configuration, the power semiconductor device 21 can be protected by the drive circuit 11 and the sensor 22 provided in the power semiconductor module 50. Therefore, the power semiconductor module 50 has a protection function. Functionalized.
　ここで、制御部１０側ではモータ駆動装置１００の中でも相対的に低い電圧の信号が流れるため、制御部１０はモータ駆動装置１００の中でも低電位となる。一方、駆動回路１１やパワー半導体装置２１などのインバータ回路の主回路ではモータ駆動装置１００の中でも相対的に高い電圧の信号が流れるため、駆動回路１１やパワー半導体装置２１などのインバータ回路の主回路はモータ駆動装置１００の中でも高電位となる。その結果、制御部１０と駆動回路１１又はパワー半導体装置２１などのインバータ回路の主回路との間には、数百から数千ボルトの電位差が生じることとなり、この電位差によって駆動回路１１又はパワー半導体装置２１などのインバータ回路の主回路側から制御部１０側へと電流が流れると制御部１０の素子が破壊されてしまうことがあった。 Here, since a signal with a relatively low voltage flows in the motor drive device 100 on the control unit 10 side, the control unit 10 has a low potential in the motor drive device 100. On the other hand, in the main circuit of the inverter circuit such as the drive circuit 11 and the power semiconductor device 21, a relatively high voltage signal flows in the motor drive device 100, and thus the main circuit of the inverter circuit such as the drive circuit 11 and the power semiconductor device 21. Is at a high potential in the motor driving apparatus 100. As a result, a potential difference of several hundreds to thousands of volts is generated between the control unit 10 and the main circuit of the inverter circuit such as the drive circuit 11 or the power semiconductor device 21, and the drive circuit 11 or the power semiconductor is generated by this potential difference. When current flows from the main circuit side of the inverter circuit such as the device 21 to the control unit 10 side, the elements of the control unit 10 may be destroyed.
　そこで、図４に示すように、信号伝送絶縁デバイス１ａを介して制御部１０と駆動回路１１又はパワー半導体装置２１などのインバータ回路との信号の伝送を行うことにより、制御部１０と駆動回路１１又はパワー半導体装置２１などのインバータ回路の主回路との間において絶縁を保つとともにセンサ信号１４や制御信号１２の伝送を行うことができる。 Therefore, as shown in FIG. 4, the control unit 10 and the drive circuit 11 are transmitted by transmitting signals between the control unit 10 and the drive circuit 11 or an inverter circuit such as the power semiconductor device 21 via the signal transmission insulating device 1a. Alternatively, it is possible to maintain insulation with the main circuit of the inverter circuit such as the power semiconductor device 21 and to transmit the sensor signal 14 and the control signal 12.
　上述したように、信号伝送絶縁デバイス１ａは絶縁耐圧を向上させるとともに信号の伝送特性の低下を抑制することができるため、所定の絶縁耐圧が設定された場合には、信号伝送絶縁デバイス１ａは他の信号伝送絶縁デバイスよりも信号の伝送速度や伝送強度といった伝送特性が高いものとなる。そのため、実施の形態１にかかる信号伝送絶縁デバイス１ａをパワー半導体モジュール５０に適用することにより、制御部１０と駆動回路１１又はパワー半導体装置２１などのインバータ回路の主回路との間の絶縁性を維持するとともに、制御信号１２やセンサ信号１４の伝送特性の向上させることができる。そして、伝送特性の向上により制御遅れ等が低減されるため、パワー半導体装置２１をより高速で動作させることができる。その結果、パワー半導体モジュール５０は、絶縁破壊に対する安全性を損なうことなく、かつ、高速での応答等が可能なパワー半導体モジュールとなる。すなわち、高品質で安全性の高いパワー半導体モジュールとなる。 As described above, since the signal transmission insulating device 1a can improve the withstand voltage and suppress the deterioration of signal transmission characteristics, when the predetermined withstand voltage is set, the signal transmission insulating device 1a The transmission characteristics such as signal transmission speed and transmission intensity are higher than those of the signal transmission insulation device. Therefore, by applying the signal transmission insulating device 1a according to the first embodiment to the power semiconductor module 50, the insulation between the control unit 10 and the main circuit of the inverter circuit such as the drive circuit 11 or the power semiconductor device 21 is provided. In addition, the transmission characteristics of the control signal 12 and the sensor signal 14 can be improved. And since the control delay etc. are reduced by the improvement of the transmission characteristic, the power semiconductor device 21 can be operated at higher speed. As a result, the power semiconductor module 50 becomes a power semiconductor module capable of high-speed response without impairing safety against dielectric breakdown. That is, the power semiconductor module has high quality and high safety.
　なお、本実施の形態では、パワー半導体モジュール５０内にセンサ２２を設けることで保護機能を有するパワー半導体モジュール５０としたが、これに限定されるものではなく、センサが設けられてなく保護機能を有さないパワー半導体モジュールであっても構わない。そのような場合でも、パワー半導体モジュールは信号伝送絶縁デバイス１ａを備えることによって駆動回路と制御部との絶縁を行うとともに制御信号１２等の伝送特性を向上させることが可能となり、高速動作等が可能となる。 In the present embodiment, the power semiconductor module 50 having the protection function is provided by providing the sensor 22 in the power semiconductor module 50. However, the present invention is not limited to this. A power semiconductor module which does not have may be used. Even in such a case, the power semiconductor module can be provided with the signal transmission insulating device 1a to insulate the drive circuit from the control unit and improve the transmission characteristics of the control signal 12 and the like, and can operate at high speed. It becomes.
実施の形態２．
　本発明の構成は、実施の形態１にかかる信号伝送絶縁デバイス１ａの構成に限定されるものでなく、他の構成とすることもできる。そこで、実施の形態１にかかる信号伝送絶縁デバイス１ａとは異なる構成について説明する。なお、以下において、本発明の実施の形態１と相違する第２絶縁膜６ａの部分について説明し、同一または対応する他の部分についての説明は省略する。 Embodiment 2. FIG.
The configuration of the present invention is not limited to the configuration of the signal transmission insulating device 1a according to the first embodiment, and may be other configurations. Therefore, a configuration different from the signal transmission insulating device 1a according to the first embodiment will be described. In the following, the second insulating film 6a that is different from the first embodiment of the present invention will be described, and description of other parts that are the same or corresponding will be omitted.
　まず、実施の形態２にかかる信号伝送絶縁デバイス１ｂの構成について説明する。図５は、本発明の実施の形態２にかかる信号伝送絶縁デバイス１ｂの構成を示す断面図である。図５において、図２と同じ符号を付けたものは、同一または対応する構成を示しており、その説明を省略する。 First, the configuration of the signal transmission insulating device 1b according to the second embodiment will be described. FIG. 5 is a sectional view showing a configuration of the signal transmission insulating device 1b according to the second exemplary embodiment of the present invention. In FIG. 5, the same reference numerals as those in FIG. 2 denote the same or corresponding components, and the description thereof is omitted.
　図５において、実施の形態２にかかる信号伝送絶縁デバイス１ｂは、実施の形態１にかかる信号伝送絶縁デバイス１ａと比較して第２絶縁膜６ａと第２絶縁膜６ｂの構成が相違する。第２絶縁膜６ｂは、第１コイル４の第２コイル５に対向する第一主面に接するとともに、第一主面に垂直な側面に接するように第１コイル４の異なる周のコイル部分の間にも設けられている。 5, the signal transmission insulating device 1b according to the second embodiment is different from the signal transmission insulating device 1a according to the first embodiment in the configuration of the second insulating film 6a and the second insulating film 6b. The second insulating film 6b is in contact with the first main surface facing the second coil 5 of the first coil 4 and is formed on the coil portions of different circumferences of the first coil 4 so as to be in contact with the side surface perpendicular to the first main surface. It is also provided in between.
　次に、本発明の実施の形態２にかかる信号伝送絶縁デバイス１ｂの製造方法について説明する。図６は、本発明の実施の形態１にかかる信号伝送絶縁デバイス１ｂの製造フローを示す断面図である。 Next, a method for manufacturing the signal transmission insulating device 1b according to the second exemplary embodiment of the present invention will be described. FIG. 6 is a cross-sectional view showing a manufacturing flow of the signal transmission insulating device 1b according to the first exemplary embodiment of the present invention.
　図６（ａ）において、Ｓｉ等からなる半導体基板２上に、ＣＶＤ法により下側絶縁膜１５を形成する。そして、下側絶縁膜１５上に、スパッタ蒸着法により、アルミニウムなどの金属膜８ａを形成する。 6A, a lower insulating film 15 is formed on the semiconductor substrate 2 made of Si or the like by a CVD method. Then, a metal film 8a such as aluminum is formed on the lower insulating film 15 by sputtering deposition.
　図６（ｂ）において、金属膜８ａをエッチングして第１コイル４を形成する。そして、第１コイル４の隣接する周のコイル部分それぞれの間と第１コイル４の第２コイル５と向かい合う面上に、ＣＶＤ法により第２絶縁膜６ｂを形成する。 6B, the first coil 4 is formed by etching the metal film 8a. Then, a second insulating film 6b is formed by a CVD method on each of the adjacent peripheral coil portions of the first coil 4 and on the surface of the first coil 4 facing the second coil 5.
　図６（ｃ）において、ＣＶＤ法により第２絶縁膜６ｂ上に第１絶縁膜３を形成する。そして、ＣＭＰ法により第１絶縁膜３を研磨して面一にする。さらに、第１絶縁膜３上に第３絶縁膜７を形成する。その後、第３絶縁膜７上に、スパッタ蒸着法により、金属膜８ｂを形成する。 In FIG. 6C, the first insulating film 3 is formed on the second insulating film 6b by the CVD method. Then, the first insulating film 3 is polished to be flush with the CMP method. Further, a third insulating film 7 is formed on the first insulating film 3. Thereafter, a metal film 8b is formed on the third insulating film 7 by sputtering deposition.
　図６（ｄ）において、金属膜８ｂをエッチングして第２コイル５を形成する。そして、第２コイル５の隣接する周のコイル部分の間と第２コイル５の上面に上側絶縁膜１６を形成する。このように、上述の１０個の工程を行うことにより、図５に示した信号伝送絶縁デバイス１ｂを得ることができる。 6 (d), the second coil 5 is formed by etching the metal film 8b. Then, the upper insulating film 16 is formed between adjacent coil portions of the second coil 5 and on the upper surface of the second coil 5. Thus, the signal transmission insulation device 1b shown in FIG. 5 can be obtained by performing the above-described ten steps.
　実施の形態２では、以上のような構成とすることにより、第１コイル４と第２コイル５との間に電位差が生じた場合に、第１コイル４と第２コイル５との間に異なる誘電率の第１絶縁膜３、第２絶縁膜６ｂ、及び第３絶縁膜７が形成されているため、第１コイル４及び第２コイル５それぞれの角部における電界集中が緩和される。その結果、絶縁膜の厚さを厚くすることなく、すなわち第１コイル４と第２コイル５との距離を長くすることなく絶縁耐圧を向上させることができるので、絶縁耐圧を向上させるとともに信号の伝送速度や伝送強度といった伝送特性の低下を抑制することができる。 In the second embodiment, the configuration as described above is different between the first coil 4 and the second coil 5 when a potential difference is generated between the first coil 4 and the second coil 5. Since the first dielectric film 3, the second dielectric film 6b, and the third dielectric film 7 having a dielectric constant are formed, the electric field concentration at the corners of the first coil 4 and the second coil 5 is alleviated. As a result, the withstand voltage can be improved without increasing the thickness of the insulating film, that is, without increasing the distance between the first coil 4 and the second coil 5. It is possible to suppress a decrease in transmission characteristics such as transmission speed and transmission intensity.
　また、実施の形態１にかかる信号伝送絶縁デバイス１ａと比較して、下側絶縁膜１５、第１コイル４、及び第２絶縁膜６ｂからなる部分の製造が簡易となることから、製造時の工程数を削減することができ、生産コストを低減することができる。 Further, as compared with the signal transmission insulating device 1a according to the first embodiment, the manufacture of the portion including the lower insulating film 15, the first coil 4, and the second insulating film 6b is simplified. The number of processes can be reduced, and the production cost can be reduced.
　さらに、実施の形態１と同様に、実施の形態２にかかる信号伝送絶縁デバイス１ｂをパワー半導体モジュールに適用することにより、高品質で安全性の高いパワー半導体モジュールを提供することができる。 Furthermore, as in the first embodiment, by applying the signal transmission insulating device 1b according to the second embodiment to a power semiconductor module, a high-quality and highly safe power semiconductor module can be provided.
　なお、本発明の実施の形態２では、本発明の実施の形態１と相違する部分について説明し、同一または対応する部分についての説明は省略した。 In the second embodiment of the present invention, portions different from the first embodiment of the present invention are described, and descriptions of the same or corresponding portions are omitted.
実施の形態３．
　実施の形態３にかかる信号伝送絶縁デバイス１ｃの構成について説明する。図７は、本発明の実施の形態３にかかる信号伝送絶縁デバイス１ｃの構成を示す断面図である。図７において、図２と同じ符号を付けたものは、同一または対応する構成を示している。また、本実施の形態は、実施の形態１と比較して、第２絶縁膜６ａ、第３絶縁膜７の構成で相違するため、以下においては当該相違点についてのみ説明し、他の構成については説明を省略する。 Embodiment 3 FIG.
A configuration of the signal transmission insulating device 1c according to the third embodiment will be described. FIG. 7: is sectional drawing which shows the structure of the signal transmission insulation device 1c concerning Embodiment 3 of this invention. 7, the same reference numerals as those in FIG. 2 denote the same or corresponding configurations. In addition, the present embodiment differs from the first embodiment in the configuration of the second insulating film 6a and the third insulating film 7. Therefore, only the difference will be described below, and other configurations will be described. Will not be described.
　図７において、実施の形態３にかかる信号伝送絶縁デバイス１ｃは、第２絶縁膜６ａ及び第３絶縁膜７には、第１絶縁膜３に用いた誘電体よりも抵抗率の低い誘電体を用いる。例えば、第１絶縁膜３としてＳｉＯ２膜を用いる場合には、一般的なＳｉＯ２膜の抵抗率は１×１０１３Ωｍであるため、第２絶縁膜６ａと第３絶縁膜７としてＳｉＮ膜を用いることができる。なお、第１絶縁膜３、第２絶縁膜６ａ、及び第３絶縁膜７の組合せは、ＳｉＯ２膜とＳｉＮ膜とに限らず、第２絶縁膜６ａと第３絶縁膜７とに用いた誘電体が第１絶縁膜３に用いた誘電体よりも抵抗率が低い組み合わせとなるように、ＳｉＯ２、ＳｉＮ、ポリイミド等の誘電体から適宜選択することができる。 In FIG. 7, in the signal transmission insulating device 1 c according to the third embodiment, the second insulating film 6 a and the third insulating film 7 are made of a dielectric having a resistivity lower than that of the dielectric used for the first insulating film 3. Use. For example, when a SiO 2 film is used as the first insulating film 3, the resistivity of a general SiO 2 film is 1 × 10 13 Ωm, and thus a SiN film is used as the second insulating film 6 a and the third insulating film 7. Can be used. The combination of the first insulating film 3, the second insulating film 6a, and the third insulating film 7 is not limited to the SiO 2 film and the SiN film, but is used for the second insulating film 6a and the third insulating film 7. The dielectric can be appropriately selected from dielectrics such as SiO 2 , SiN, and polyimide so that the dielectric has a combination having a lower resistivity than the dielectric used for the first insulating film 3.
　なお、本発明の実施の形態３にかかる信号伝送絶縁デバイス１ｃの製造方法については、実施の形態１にかかる信号伝送絶縁デバイス１ａの製造方法と同じである。 The method for manufacturing the signal transmission insulating device 1c according to the third embodiment of the present invention is the same as the method for manufacturing the signal transmission insulating device 1a according to the first embodiment.
　実施の形態３では、以上のような構成とすることにより、第１コイル４と第２コイル５との間に電位差が生じた場合に、第１コイル４と第２コイル５との間に異なる抵抗率の第１絶縁膜３、第２絶縁膜６ｂ、及び第３絶縁膜７が形成されているため、第１コイル４及び第２コイル５それぞれの角部における電界集中が緩和される。その結果、絶縁膜の厚さを厚くすることなく、すなわち第１コイル４と第２コイル５との距離を長くすることなく絶縁耐圧を向上させることができるので、絶縁耐圧を向上させるとともに信号の伝送速度や伝送強度といった伝送特性の低下を抑制することができる。 In the third embodiment, the configuration as described above is different between the first coil 4 and the second coil 5 when a potential difference occurs between the first coil 4 and the second coil 5. Since the first insulating film 3, the second insulating film 6 b, and the third insulating film 7 having the resistivity are formed, the electric field concentration at the corners of the first coil 4 and the second coil 5 is alleviated. As a result, the withstand voltage can be improved without increasing the thickness of the insulating film, that is, without increasing the distance between the first coil 4 and the second coil 5. It is possible to suppress a decrease in transmission characteristics such as transmission speed and transmission intensity.
　また、本実施の形態のように、第２絶縁膜６ａと第３絶縁膜７に相対的に抵抗率の低い絶縁材料を用いると、薄膜トランス構造９を構成する第１コイル４の隣り合うコイル間、又は第２コイル５の隣り合うコイル間において、第２絶縁膜６ａ又は第３絶縁膜７を介して電気的に短絡することで、トランスとしての機能を失ってしまう恐れがある。そこで、第２絶縁膜６ａと第３絶縁膜７とは、第１コイル４の隣り合うコイル間又は第２コイル５の隣り合うコイル間において電気的に短絡しない抵抗率以上の抵抗率とする。 In addition, when an insulating material having a relatively low resistivity is used for the second insulating film 6a and the third insulating film 7 as in the present embodiment, adjacent coils of the first coil 4 constituting the thin film transformer structure 9 are used. Between the adjacent coils of the second coil 5 or between the adjacent coils of the second coil 5, there is a possibility that the function as a transformer may be lost by short-circuiting via the second insulating film 6 a or the third insulating film 7. Therefore, the second insulating film 6 a and the third insulating film 7 have a resistivity equal to or higher than a resistivity that does not cause an electrical short circuit between adjacent coils of the first coil 4 or between adjacent coils of the second coil 5.
　図８に、実施の形態３にかかる信号伝送絶縁デバイス１ｃの動作波形を示す。図８において、図８（ａ）は入力矩形波電気信号を示し、図８（ｂ）は出力パルス電気信号を示す。また、縦軸は各信号の電圧を示し、横軸は時間を示している。例えば、図８（ａ）に示すように、第１コイル４又は第２コイル５のいずれか一方に対して矩形波電気信号Ｖｉｎが入力され、入力された矩形波電気信号Ｖｉｎの立上りと立下りに対応して、他方のコイルに周波数Ｆのパルス電気信号Ｖｏｕｔが出力される。かかる場合、図８（ｂ）に示す半周期Ｔ／２が０．５［ｎｓ］、すなわち周波数Ｆが１ＧＨｚとすると、パルス電気信号Ｖｏｕｔが出力される第１コイル４又は第２コイル５の隣り合うコイル間が電気的に短絡しないためには、隣り合うコイル間の時定数τが式（１）を満たす必要がある。 FIG. 8 shows operation waveforms of the signal transmission insulating device 1c according to the third embodiment. 8A shows an input rectangular wave electric signal, and FIG. 8B shows an output pulse electric signal. The vertical axis represents the voltage of each signal, and the horizontal axis represents time. For example, as shown in FIG. 8 (a), a rectangular wave electric signal V in respect one of the first coil 4 and second coil 5 is input, the rising of the input square wave electrical signal V in Corresponding to the falling, a pulse electric signal Vout having a frequency F is output to the other coil. In such a case, when the half cycle T / 2 shown in FIG. 8B is 0.5 [ns], that is, the frequency F is 1 GHz, the first coil 4 or the second coil 5 that outputs the pulse electric signal V out is output. In order to prevent an electrical short circuit between adjacent coils, the time constant τ between adjacent coils needs to satisfy the formula (1).
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000001
　時定数τは抵抗率ρと比誘電率εｒ、真空の誘電率ε０を用いて、式（２）によって求まる。 The time constant τ is obtained by the equation (2) using the resistivity ρ, the relative dielectric constant ε r , and the vacuum dielectric constant ε 0 .
Figure JPOXMLDOC01-appb-M000002
Figure JPOXMLDOC01-appb-M000002
　第２絶縁膜６ａと第３絶縁膜７がＳｉＮ膜の場合、ＳｉＮ膜のεｒを７、ε０を８．８５×１０－１２Ｆ／ｍとすると、式（１）及び（２）より、第２絶縁膜６ａと第３絶縁膜７の抵抗率は１６Ωｍよりも大きいものでなければならない。よって、ＳｉＮ膜として抵抗率は１６Ωｍよりも大きいものを選択することとすればよい。 When the second insulating film 6a and the third insulating film 7 are SiN films, if ε r of the SiN film is 7 and ε 0 is 8.85 × 10 −12 F / m, the equations (1) and (2) The resistivity of the second insulating film 6a and the third insulating film 7 must be greater than 16Ωm. Therefore, a SiN film having a resistivity larger than 16 Ωm may be selected.
　さらに、実施の形態１と２と同様に、実施の形態２にかかる信号伝送絶縁デバイス１ｃをパワー半導体モジュールに適用することにより、高品質で安全性の高いパワー半導体モジュールを提供することができる。 Furthermore, as in the first and second embodiments, by applying the signal transmission insulating device 1c according to the second embodiment to a power semiconductor module, a high-quality and highly safe power semiconductor module can be provided.
実施の形態４．
　実施の形態４にかかる信号伝送絶縁デバイス１ｄの構成について説明する。図９は、本発明の実施の形態４にかかる信号伝送絶縁デバイス１ｄの構成を示す断面図である。図９において、図５と同じ符号を付けたものは、同一または対応する構成を示している。また、本実施の形態は、実施の形態２と比較して、第２絶縁膜６ｂ、第３絶縁膜７の構成で相違するため、以下においては当該相違点についてのみ説明し、他の構成については説明を省略する。 Embodiment 4 FIG.
A configuration of the signal transmission insulating device 1d according to the fourth exemplary embodiment will be described. FIG. 9: is sectional drawing which shows the structure of the signal transmission insulation device 1d concerning Embodiment 4 of this invention. 9, the same reference numerals as those in FIG. 5 denote the same or corresponding configurations. In addition, the present embodiment differs from the second embodiment in the configuration of the second insulating film 6b and the third insulating film 7, so that only the difference will be described below and other configurations will be described. Will not be described.
　図９において、実施の形態４にかかる信号伝送絶縁デバイス１ｄは、第２絶縁膜６ｂ及び第３絶縁膜７には、第１絶縁膜３に用いた誘電体よりも抵抗率の低い誘電体を用いる。例えば、第１絶縁膜３としてＳｉＯ２膜を用いる場合には、一般的なＳｉＯ２膜の抵抗率は１×１０１３Ωｍであるため、第２絶縁膜６ｂと第３絶縁膜７としてＳｉＮ膜を用いることができる。なお、第１絶縁膜３、第２絶縁膜６ｂ、及び第３絶縁膜７の組合せは、ＳｉＯ２膜とＳｉＮ膜とに限らず、第２絶縁膜６ｂと第３絶縁膜７とに用いた誘電体が第１絶縁膜３に用いた誘電体よりも抵抗率が低い組み合わせとなるように、ＳｉＯ２、ＳｉＮ、ポリイミド等の誘電体から適宜選択することができる。 In FIG. 9, in the signal transmission insulating device 1 d according to the fourth exemplary embodiment, the second insulating film 6 b and the third insulating film 7 are made of a dielectric having a resistivity lower than that of the dielectric used for the first insulating film 3. Use. For example, when a SiO 2 film is used as the first insulating film 3, the resistivity of a general SiO 2 film is 1 × 10 13 Ωm, and thus a SiN film as the second insulating film 6 b and the third insulating film 7. Can be used. The combination of the first insulating film 3, the second insulating film 6b, and the third insulating film 7 is not limited to the SiO 2 film and the SiN film, but is used for the second insulating film 6b and the third insulating film 7. The dielectric can be appropriately selected from dielectrics such as SiO 2 , SiN, and polyimide so that the dielectric has a combination having a lower resistivity than the dielectric used for the first insulating film 3.
　また、実施の形態３と同様に、出力されるパルス電気信号Ｖｏｕｔの周波数Ｆを１ＧＨｚとすると、第１絶縁膜３としてＳｉＯ２膜を用いる場合、第２絶縁膜６ｂと第３絶縁膜７の抵抗率は１６Ωｍよりも大きければよい。 Similarly to the third embodiment, when the frequency F of the output pulse electric signal Vout is 1 GHz, when the SiO 2 film is used as the first insulating film 3, the second insulating film 6b and the third insulating film 7 are used. The resistivity should be larger than 16 Ωm.
　本発明の実施の形態４にかかる信号伝送絶縁デバイス１ｄの製造方法については、実施の形態２にかかる信号伝送絶縁デバイス１ｂの製造方法と同じである。 The manufacturing method of the signal transmission insulating device 1d according to the fourth embodiment of the present invention is the same as the manufacturing method of the signal transmission insulating device 1b according to the second embodiment.
　実施の形態４では、以上のような構成とすることにより、第１コイル４と第２コイル５との間に電位差が生じた場合に、第１コイル４と第２コイル５との間に異なる抵抗率の第１絶縁膜３、第２絶縁膜６ｂ、及び第３絶縁膜７が形成されているため、第１コイル４及び第２コイル５それぞれの角部における電界集中が緩和される。その結果、絶縁膜の厚さを厚くすることなく、すなわち第１コイル４と第２コイル５との距離を長くすることなく絶縁耐圧を向上させることができるので、絶縁耐圧を向上させるとともに信号の伝送速度や伝送強度といった伝送特性の低下を抑制することができる。 In the fourth embodiment, the configuration as described above is different between the first coil 4 and the second coil 5 when a potential difference is generated between the first coil 4 and the second coil 5. Since the first insulating film 3, the second insulating film 6 b, and the third insulating film 7 having the resistivity are formed, the electric field concentration at the corners of the first coil 4 and the second coil 5 is alleviated. As a result, the withstand voltage can be improved without increasing the thickness of the insulating film, that is, without increasing the distance between the first coil 4 and the second coil 5. It is possible to suppress a decrease in transmission characteristics such as transmission speed and transmission intensity.
　また、実施の形態１又は３にかかる信号伝送絶縁デバイス１ａ、１ｃ比較して、下側絶縁膜１５、第１コイル４、及び第２絶縁膜６ｂからなる部分の製造が簡易となることから、製造時の工程数を削減することができ、生産コストを低減することができる。 In addition, compared to the signal transmission insulating devices 1a and 1c according to the first or third embodiment, the manufacturing of the portion including the lower insulating film 15, the first coil 4, and the second insulating film 6b is simplified. The number of processes during manufacturing can be reduced, and the production cost can be reduced.
　さらに、実施の形態１ないし３と同様に、実施の形態２にかかる信号伝送絶縁デバイス１ｂをパワー半導体モジュールに適用することにより、高品質で安全性の高いパワー半導体モジュールを提供することができる。 Furthermore, similarly to the first to third embodiments, by applying the signal transmission insulating device 1b according to the second embodiment to a power semiconductor module, a high-quality and highly safe power semiconductor module can be provided.
　なお、本発明は、発明の範囲内において、各実施の形態を自由に組み合わせることや、各実施の形態を適宜、変形、省略することが可能である。 In the present invention, the embodiments can be freely combined within the scope of the invention, and the embodiments can be appropriately modified or omitted.
１ａ　１ｂ　１ｃ　１ｄ　信号伝送絶縁デバイス、２　半導体基板、
３　第１絶縁膜、４　第１コイル、５　第２コイル、
６ａ　６ｂ　第２絶縁膜、７　第３絶縁膜、８ａ　８ｂ　金属膜、
９　薄膜トランス構造、１０　制御部、１１　駆動回路、
１２　制御信号、１３　駆動信号、１４　センサ信号、
１５　下側絶縁膜、１６　上側絶縁膜、１７　絶縁膜、
２１　パワー半導体装置、２２　センサ、３０　モータ、
５０　パワー半導体モジュール、１００　モータ駆動装置。 1a 1b 1c 1d signal transmission insulation device, 2 semiconductor substrate,
3 first insulating film, 4 first coil, 5 second coil,
6a 6b second insulating film, 7 third insulating film, 8a 8b metal film,
9 Thin-film transformer structure, 10 control unit, 11 drive circuit,
12 control signal, 13 drive signal, 14 sensor signal,
15 lower insulating film, 16 upper insulating film, 17 insulating film,
21 power semiconductor devices, 22 sensors, 30 motors,
50 power semiconductor module, 100 motor drive device.

Claims (9)

  1. 第１コイルと、
    前記第１コイルに対向し前記第１コイルとともにトランスを構成する第２コイルと、
    前記第１コイルと前記第２コイルとが対向する間に設けられ、第１の誘電体からなる第１絶縁膜と、
    前記第１コイルの前記第２コイルに対向する第一主面と前記第１絶縁膜の前記第１コイルに対向する面との間に設けられ、前記第１の誘電体よりも誘電率が高い第２の誘電体からなる第２絶縁膜と、
    前記第２コイルの前記第１コイルに対向する第二主面と前記第１絶縁膜の前記第２コイルに対向する面との間に設けられ、前記第１の誘電体よりも誘電率が高い第３の誘電体からなる第３絶縁膜と、
    を備えたことを特徴とする信号伝送絶縁デバイス。     A first coil;
    A second coil that faces the first coil and forms a transformer together with the first coil;
    A first insulating film provided between the first coil and the second coil and made of a first dielectric;
    Provided between the first main surface of the first coil that faces the second coil and the surface of the first insulating film that faces the first coil, and has a higher dielectric constant than the first dielectric. A second insulating film made of a second dielectric;
    Provided between the second main surface of the second coil that faces the first coil and the surface of the first insulating film that faces the second coil, and has a higher dielectric constant than the first dielectric. A third insulating film made of a third dielectric;
    A signal transmission insulation device comprising:
  2. 第１コイルと、
    前記第１コイルに対向し前記第１コイルとともにトランスを構成する第２コイルと、
    前記第１コイルと前記第２コイルとが対向する間に設けられ、第１の誘電体からなる第１絶縁膜と、
    前記第１コイルの前記第２コイルに対向する第一主面と前記第１絶縁膜の前記第１コイルに対向する面との間に設けられ、前記第１の誘電体よりも抵抗率が低い第２の誘電体からなる第２絶縁膜と、
    前記第２コイルの前記第１コイルに対向する第二主面と前記第１絶縁膜の前記第２コイルに対向する面との間に設けられ、前記第１の誘電体よりも抵抗率が低い第３の誘電体からなる第３絶縁膜と、
    を備えたことを特徴とする信号伝送絶縁デバイス。     A first coil;
    A second coil that faces the first coil and forms a transformer together with the first coil;
    A first insulating film provided between the first coil and the second coil and made of a first dielectric;
    Provided between a first main surface of the first coil facing the second coil and a surface of the first insulating film facing the first coil, and having a lower resistivity than the first dielectric. A second insulating film made of a second dielectric;
    Provided between a second main surface of the second coil facing the first coil and a surface of the first insulating film facing the second coil, and having a lower resistivity than the first dielectric. A third insulating film made of a third dielectric;
    A signal transmission insulation device comprising:
  3. 前記第２絶縁膜は、前記第１コイルの前記第一主面を覆うように形成され、
    前記第３絶縁膜は、前記第２コイルの前記第二主面を覆うように形成される、
    ことを特徴とする請求項１又は２に記載の信号伝送絶縁デバイス。     The second insulating film is formed so as to cover the first main surface of the first coil,
    The third insulating film is formed so as to cover the second main surface of the second coil.
    The signal transmission insulation device according to claim 1 or 2, wherein
  4. 前記第１コイルは半導体基板上に形成され、
    前記第２絶縁膜は前記第１コイルの前記第一主面に垂直な側面に接するように設けられている、
    ことを特徴とする請求項３記載の信号伝送絶縁デバイス。     The first coil is formed on a semiconductor substrate;
    The second insulating film is provided in contact with a side surface perpendicular to the first main surface of the first coil;
    The signal transmission insulation device according to claim 3.
  5. 前記第１絶縁膜では圧縮応力が発生し、
    前記第２絶縁膜及び前記第３絶縁膜では引張応力が発生する、
    ことを特徴とする請求項１乃至４のいずれか１項に記載の信号伝送絶縁デバイス。     Compressive stress is generated in the first insulating film,
    Tensile stress is generated in the second insulating film and the third insulating film.
    5. The signal transmission insulation device according to claim 1, wherein
  6. 前記第１の誘電体はＳｉＯ２である、
    ことを特徴とする請求項１乃至５のいずれか１項に記載の信号伝送絶縁デバイス。     The first dielectric is SiO 2 ;
    The signal transmission insulation device according to claim 1, wherein
  7. 前記第２の誘電体はＳｉＮである、
    ことを特徴とする請求項１乃至６のいずれか１項に記載の信号伝送絶縁デバイス。     The second dielectric is SiN;
    The signal transmission insulating device according to claim 1, wherein
  8. 前記第３の誘電体はＳｉＮである、
    ことを特徴とする請求項１乃至７のいずれか１項に記載の信号伝送絶縁デバイス。     The third dielectric is SiN;
    The signal transmission insulation device according to claim 1, wherein the signal transmission insulation device is a signal transmission insulation device.
  9. パワー半導体装置と、
    前記パワー半導体装置を駆動する駆動回路と、
    前記駆動回路と前記パワー半導体装置を制御する制御回路との間の信号を伝送するとともに、前記駆動回路と前記制御回路とを絶縁する請求項１乃至８のいずれか１項に記載の信号伝送デバイスと、
    を備えたことを特徴とするパワー半導体モジュール。     A power semiconductor device;
    A drive circuit for driving the power semiconductor device;
    The signal transmission device according to claim 1, wherein the signal transmission device transmits a signal between the drive circuit and a control circuit that controls the power semiconductor device, and insulates the drive circuit from the control circuit. When,
    A power semiconductor module comprising:
PCT/JP2013/079537 2013-01-18 2013-10-31 Signal transmission insulation device and power semiconductor module WO2014112179A1 (en)

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