JP2011096699A - Semiconductor device, and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor device and a method of manufacturing the same, which can detect heat generation rapidly and can be manufactured with a relatively small number of manufacturing processes without increasing size. <P>SOLUTION: A temperature sensor 41 includes a temperature sensor wiring part 31 and a temperature sensor electrode part 32 formed of metal material, and is arranged on an upper layer insulation film 30 and on a region except for a region with a source electrode output pad 35 of a source electrode 20 formed thereon. Thereby, the temperature sensor 41 is arranged without increasing the size of the semiconductor device 1. In addition with the relatively small number of manufacturing processes, the semiconductor device 1 provided with the temperature sensor 41 can be manufactured. Furthermore, as defect such as overheating of the source electrode 41 can be rapidly detected by the temperature sensor 41, breakage of the semiconductor device 1 can be prevented by arranging a protection circuit for stopping operation of the semiconductor device 1 when the defect is detected by the temperature sensor 41. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a semiconductor device and a manufacturing method thereof, and more particularly to a semiconductor device using a silicon carbide semiconductor and a manufacturing method thereof.

  A semiconductor device using a silicon carbide (SiC) semiconductor is superior in operation at a high voltage, a large current, and a high temperature as compared with a semiconductor device formed of a silicon (Si) semiconductor. Development as a semiconductor device is underway. SiC semiconductors are superior in operation at high currents and high temperatures than Si semiconductors. However, if an excessively large current flows, the element is destroyed by heat generation. A technique for preventing such element destruction is disclosed in Patent Document 1, for example.

  In the semiconductor device disclosed in Patent Document 1, a PN junction temperature sensor is formed on the same substrate as the element. The semiconductor device is configured to detect the temperature of an element by a temperature sensor and to stop the operation of the element by a protection circuit connected to the temperature sensor when there is heat generation leading to destruction of the element.

JP 2005-175357 A

  In the semiconductor device disclosed in Patent Document 1 described above, the following manufacturing process is required to form a temperature sensor. First, a polycrystalline semiconductor film is formed on the insulating film of the substrate, and ion implantation is performed while partially masking. Next, patterning and annealing are performed to form a PN junction temperature sensor of the polycrystalline semiconductor film. Then, metal wiring and metal electrode pads for external connection are formed on each of the P-type and N-type semiconductor films constituting the temperature sensor. As described above, the semiconductor device disclosed in Patent Document 1 has a problem in that the number of manufacturing steps increases, so that the yield decreases and the manufacturing cost increases.

  In addition, since the PN junction temperature sensor needs to be formed in a region other than the main portion through which the current of the semiconductor device flows, the provision of the PN junction temperature sensor increases the chip size and increases the manufacturing cost. Arise. In addition, the semiconductor device generates heat in the main part described above. However, since the temperature sensor of the PN junction is formed in a region other than the main part as described above, detection of heat generation is delayed and detection of abnormality such as overheating is delayed. There is a problem.

  An object of the present invention is to provide a semiconductor device that can quickly detect heat generation without increasing its size, and can be manufactured with a relatively small number of manufacturing steps, and a manufacturing method thereof.

  A semiconductor device of the present invention includes a semiconductor element including an external output electrode connected to the outside, an insulating film that covers the external output electrode, and a temperature sensor that detects a temperature of the semiconductor element, and the temperature sensor A temperature sensor wiring portion made of a metal material, and a temperature sensor electrode portion made of a metal material, connected to both ends of the temperature sensor wiring portion and connected to the outside, and the temperature sensor wiring portion and The temperature sensor electrode portion is provided on the insulating film of the semiconductor element and on an area of the external output electrode other than an area where an electrode pad connected to the outside is formed. .

  A method for manufacturing a semiconductor device according to the present invention is a method for manufacturing a semiconductor device comprising a semiconductor element provided on a semiconductor substrate and a temperature sensor for detecting the temperature of the semiconductor element, the semiconductor device being externally provided on the semiconductor substrate. Forming a semiconductor element body including an external output electrode to be connected; forming an insulating film so as to cover the external output electrode; and forming the semiconductor element; and on the insulating film, Of the external output electrodes, a step of forming a metal film made of a metal material on a region other than a region where an electrode pad connected to the outside is formed, and by partially removing the metal film, a wiring shape Forming a temperature sensor wiring portion and a temperature sensor electrode portion connected to both ends of the temperature sensor wiring portion and connected to the outside to form the temperature sensor. .

  According to the semiconductor device of the present invention, the semiconductor device includes the semiconductor element and the temperature sensor. Since both the temperature sensor wiring portion and the temperature sensor electrode portion of the temperature sensor are made of a metal material, they can be formed at the same time. As a result, the number of manufacturing processes for forming the temperature sensor can be reduced as compared with the case where the temperature sensor is configured with a PN junction element as in the prior art, so that the semiconductor device can be manufactured with a relatively small number of manufacturing processes. Can be manufactured. Therefore, mass productivity can be improved and manufacturing cost can be reduced.

  The temperature sensor is provided on an insulating film covering the external output electrode of the semiconductor element and on a region other than the region where the electrode pad of the external output electrode is formed. As a result, the temperature sensor can be provided without reducing the effective area of the semiconductor element, so that an increase in size and an increase in manufacturing cost due to the provision of the temperature sensor can be suppressed. In addition, as described above, by providing a temperature sensor in a region other than the region where the electrode pad of the external output electrode is formed, heat generation of the external output electrode can be detected quickly. Abnormalities such as electrode overheating can be detected more quickly. The external output electrode is a portion that is easily damaged by heat generation in the semiconductor element. Since the abnormality of the external output electrode can be detected earlier than the conventional technique as described above, it is possible to more reliably prevent the semiconductor element from being destroyed by heat generation.

  According to the method for manufacturing a semiconductor device of the present invention, the semiconductor element body is formed on the semiconductor substrate, and the insulating film is formed so as to cover the external output electrode of the semiconductor element body. A metal film is formed on the insulating film on a region other than the region where the electrode pad of the external output electrode is formed. The metal film is partially removed to form a temperature sensor including a temperature sensor wiring portion and a temperature sensor electrode portion. As a result, the temperature sensor wiring part and the temperature sensor electrode part can be formed at the same time, so that the manufacturing for forming the temperature sensor is performed as compared with the case where the temperature sensor is configured with a PN junction element as in the prior art. The number of processes can be reduced. Therefore, a semiconductor device can be manufactured with a relatively small number of manufacturing steps, so that mass productivity can be improved and manufacturing cost can be reduced.

  Further, the temperature sensor wiring part and the temperature sensor electrode part are formed on the insulating film covering the external output electrode of the semiconductor element and on the region other than the region where the electrode pad of the external output electrode is formed. Therefore, it is possible to suppress the increase in size and the manufacturing cost due to the provision of. In addition, it is possible to realize a semiconductor device that can quickly detect the heat generation of the external output electrode, so that it is possible to detect abnormalities such as overheating of the external output electrode earlier than in the prior art. A semiconductor device that can more reliably prevent element destruction can be manufactured.

1 is a plan view showing a semiconductor device 1 according to a first embodiment of the present invention. It is sectional drawing which shows the semiconductor device 1 seen from the cut surface line II-II of FIG. 6 is a cross-sectional view showing a state at a stage where the formation of the interlayer insulating film 18 is completed. FIG. FIG. 6 is a cross-sectional view showing a state in which the formation of the drain electrode 19 is completed. It is sectional drawing which shows the state in the stage where formation of the temperature sensor wiring part 31 and the temperature sensor electrode part 32 was complete | finished. It is sectional drawing which shows the state of the stage which the formation of the protective film 33 and the back surface connection electrode 21 was complete | finished. It is a top view which shows 1 A of semiconductor devices which are the 2nd Embodiment of this invention. It is a top view which shows the semiconductor device 1B which is the 3rd Embodiment of this invention.

<First Embodiment>
FIG. 1 is a plan view showing a semiconductor device 1 according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view showing the semiconductor device 1 as viewed along the section line II-II in FIG. FIG. 1 shows the semiconductor device 1 with the protective film 33 shown in FIG. 2 removed for easy understanding. In the present embodiment, semiconductor device 1 is a semiconductor device using a silicon carbide (SiC) semiconductor. The semiconductor device 1 is suitably used as a power semiconductor device. In a semiconductor device 1, a field effect transistor (abbreviation: FET) 10 having a metal oxide semiconductor (abbreviation: MOS) structure is formed on a silicon carbide (SiC) substrate 11 which is a semiconductor substrate. ing. Hereinafter, the MOSFET having the MOS structure is referred to as “MOSFET”.

  As shown in FIG. 1, the external output pad of the semiconductor device 1 includes a drain electrode 19 formed on the entire surface on one side in the thickness direction of the SiC substrate 11 and a source electrode formed on the other side in the thickness direction of the SiC substrate 11. An output pad 35, a gate electrode output pad 36, and two temperature sensor output pads 34 are provided. The drain electrode 19 itself functions as an external output pad. The source electrode output pad 35 is an external output pad of the source electrode 20. The gate electrode output pad 36 is an external output pad of the gate electrode 17. The temperature sensor output pad 34 is an external output pad of the temperature sensor 41.

  The temperature sensor 41 includes a temperature sensor wiring part 31 formed of a metal wiring resistor and a temperature sensor electrode part 32 electrically connected to the temperature sensor wiring part 31. The temperature sensor electrode unit 32 functions as an external output electrode. The temperature sensor wiring part 31 is disposed around the outside of the source electrode output pad 35 so as to surround the source electrode output pad 35. The temperature sensor wiring part 31 is the same metal as the temperature sensor electrode part 32 that is an external output electrode of the temperature sensor 41, for example, aluminum (Al), platinum (Pt), palladium (Pd), titanium (Ti), and tungsten (W). It is formed of one or more metals selected from In FIG. 1, the temperature sensor wiring portion 31 is indicated by a thick solid line for easy understanding.

  MOSFET 10 is an n-channel MOSFET in the present embodiment. As shown in FIG. 2, the MOSFET 10 includes a SiC substrate 11, a drift region 12, a source region 13, a base region 14, and a high-concentration p-type (hereinafter sometimes referred to as “p +”) region p +. Contact region 15, gate oxide film 16, gate electrode 17, interlayer insulating film 18, drain electrode 19, source electrode 20, back surface connection electrode 21, thick film insulating film 24, and external output gate electrode 25 And a silicide film 28. SiC substrate 11, drift region 12, source region 13, base region 14, p + contact region 15, gate oxide film 16, gate electrode 17, interlayer insulating film 18, drain electrode 19, source electrode 20, back surface connection electrode 21, and thick film The insulating film 24 constitutes a semiconductor element body.

  The external output gate electrode 25 is electrically connected to the gate electrode 17 and functions as an external output electrode of the gate electrode 17. As shown in FIG. 1, the external output gate electrode 25 is provided so as to surround the source electrode 20, and is electrically connected to the gate electrode 17 through the plurality of gate contact holes 23 around the source electrode 20. Is done. The external output gate electrode 25 constitutes an external output pad 36 of the gate electrode 17. External output gate electrode 25 is made of, for example, aluminum.

  The source electrode 20 itself functions as an external output electrode. Hereinafter, the source electrode 20 may be referred to as “external output source electrode 20”. Source electrode 20 is electrically connected to source region 13 and p + contact region 15 through source contact hole 22. The source electrode 20 is formed of the same metal as the external output gate electrode 25, for example, aluminum.

  The temperature sensor wiring part 31 and the temperature sensor electrode part 32 of the temperature sensor 41 are formed on the upper insulating film 30 formed on the source electrode 20. A protective film 33 made of, for example, a polyimide film is formed on the temperature sensor wiring portion 31. The protective film 33 is opened at portions of the source electrode output pad 35, the gate electrode output pad 36, and the two temperature sensor output pads 34. In the portion of the source electrode output pad 35, the upper insulating film 30 is also opened. The source electrode output pad 35 is configured by a portion of the source electrode 20 exposed through the source opening 43 formed in the upper insulating film 30 and the protective film 33. The gate electrode output pad 36 is configured by a portion of the external output gate electrode 25 exposed through the gate opening 44 formed in the protective film 33. The temperature sensor output pad 34 is configured by a portion of the temperature sensor electrode part 32 exposed through the sensor opening 42 formed in the protective film 33.

  SiC substrate 11 is, for example, a high-concentration n-type (hereinafter sometimes referred to as “n +”) semiconductor substrate, and is realized by, for example, a wafer. The SiC substrate 11 is a semiconductor substrate made of SiC and having a wide band gap wider than that of a silicon (Si) substrate. A drift region 12, which is a low-concentration n-type (hereinafter sometimes referred to as “n−”) semiconductor layer, is formed on the SiC substrate 11. Drift region 12 is formed by epitaxial growth on SiC substrate 11.

  In a predetermined region of the surface layer portion of the drift region 12, an n + type source region 13, a p type base region 14, and a p + type p + contact region 15 that are current output regions are formed. The base region 14 is selectively formed in the surface layer portion of the drift region 12 surrounding the source region 13. The base region 14 is formed such that the depth dimension from the surface thereof is larger than the depth dimension from the surface of the source region 13. The source region 13 is selectively formed in the surface layer portion of the base region 14.

  A p + contact region 15 is formed in the center of the source region 13. The p + contact region 15 is for making electrical contact between the source electrode 20 and the base region 14. Hereinafter, the drift region 12, the source region 13, the base region 14, and the p + contact region 15 may be collectively referred to as “first SiC regions 12 to 15”. The source region 13 and the p + contact region 15 may be collectively referred to as “second SiC regions 13 and 15”.

  A gate electrode 17 made of, for example, a polysilicon film is formed on drift region 12 with gate oxide film 16 interposed. As shown in FIG. 2, the gate electrode 17 extends to the thickness of the thick insulating film 24 formed around the source electrode 20. The thick insulating film 24 is formed thicker than the gate oxide film 16. In the present embodiment, an oxide film such as a silicon oxide film is used as the thick film insulating film 24. The thick film insulating film 24 is not limited to the oxide film, and in another embodiment of the present invention, another insulating film may be used as the thick film insulating film 24 instead of the oxide film.

  An interlayer insulating film 18 is formed so as to cover the gate electrode 17. Interlayer insulating film 18 is made of, for example, an oxide film. In the interlayer insulating film 18 and the gate oxide film 16, a source contact hole 22, which is a first contact hole, is opened in order to make contact between the second SiC regions 13 and 15 and the source electrode 20. Source contact hole 22 is formed by etching away interlayer insulating film 18 and gate oxide film 16 on second SiC regions 13 and 15. In addition, the interlayer insulating film 23 is a second contact hole gate for making contact between the gate electrode 17 formed on the drift region 12 via the thick film insulating film 24 and the external output gate electrode 25. A contact hole 23 is opened. The gate contact hole 23 is formed by etching away the interlayer insulating film 23 on the gate electrode 17.

  The external output source electrode 20 is electrically connected to the source region 13 and the p + contact region 15 in the source contact hole 22. On the other hand, an external output gate electrode 25 made of, for example, an aluminum film is formed on the interlayer insulating film 18 around the external output source electrode 20. The external output gate electrode 25 is electrically connected to the gate electrode 17 in the gate contact hole 23.

  A drain electrode 19 is formed on the surface on the other side in the thickness direction of SiC substrate 11. In the present embodiment, the drain electrode 19 is made of a metal film and a silicide film. The silicide film constituting the drain electrode 19 is, for example, a nickel silicide (NiSi) film. A back connection electrode 21 is formed on the drain electrode 19. In the present embodiment, the back connection electrode 21 is composed of a laminated film of a first metal film 21a and a second metal film 21b. The back surface connection electrode 21 is made of, for example, a nickel (Ni) / gold (Au) laminated film in which the first metal film 21a is a nickel (Ni) film and the second metal film 21b is a gold (Au) film. .

  Even when a high voltage is applied between the external output source electrode 20 and the back surface connection electrode 19, if no voltage is applied to the gate electrode 17, the base region 14 formed immediately below the gate electrode 17 is applied to the base region 14. Since no channel is formed, electrons do not flow. Therefore, when no voltage is applied to the gate electrode 17, the semiconductor device 1 is turned off. When a positive voltage is applied to the gate electrode 17, a channel is formed above the base region 14, and electrons are transferred from the source region 13 to the base region 14, the drift region 12, the SiC substrate 11, and the drain electrode 19 that are channel regions. It begins to flow. Therefore, when a voltage is applied to the gate electrode 17, the semiconductor device 1 is turned on. As described above, whether or not a current flows in the semiconductor device 1, that is, whether the semiconductor device 1 is on or off can be controlled by the gate voltage that is a voltage applied to the gate electrode 17.

  Next, a method for manufacturing the semiconductor device 1 according to the first embodiment of the present invention will be described. 3 to 6 are views for explaining a method of manufacturing the semiconductor device 1 according to the first embodiment of the present invention. FIG. 3 is a cross-sectional view showing a state in which the formation of the interlayer insulating film 18 has been completed. First, drift region 12 which is an n-type semiconductor layer made of silicon carbide is formed on SiC substrate 11 by epitaxial growth.

  Next, a p-type base region 14 is selectively formed on the upper surface portion of the drift region 12 by, for example, photoengraving and ion implantation, and an n + -type source region 13 and an upper portion of the base region 14 A p + contact region 15 which is a p-type base contact region is selectively formed. Specifically, the base region 14, the source region 13, and the p + contact region 15 are formed by implanting impurity ions into each region and then activating them by annealing at a high temperature of 1500 ° C. or higher. An n-type impurity, for example, nitrogen (N) ions are implanted into a portion that becomes the source region 13 that is an n-type region. A p-type impurity, for example, aluminum (Al) ions are implanted into the base region 14 and the p + contact region 15 which are p-type regions.

  Next, an oxide film having a thickness of about 1 μm is formed as an insulating film to be the thick insulating film 24 on the drift region 12 by, for example, a chemical vapor deposition (abbreviation: CVD) method. Thereafter, the oxide film formed in the unit cell formation portion 10A of the MOSFET 10 is removed by photolithography and etching. As a result, the thick insulating film 24 is formed around the unit cell forming portion 10A of the MOSFET 10.

  Thereafter, by oxidizing the upper portions of the first SiC regions 12 to 15 of the unit cell formation portion 10A of the MOSFET 10 in an atmosphere containing oxygen and water vapor at a temperature of about 1000 ° C., a thermal oxide film is formed as the gate oxide film 16. Form. Hereinafter, the gate oxide film 16 will be described as a thermal oxide film. However, the gate oxide film 16 is not limited to this, and may be an oxide film formed by a CVD method, or a combination of these oxide films. There may be.

  Next, a polycrystalline silicon film that is a polysilicon film to be the gate electrode 17 is formed by, for example, CVD, and photolithography and etching are performed. As a result, in the unit cell formation portion 10A of the MOSFET 10, the gate electrode 17 is formed on the base region 14 sandwiched between the drift region 12 and the source region 13 via the gate oxide film 16. Further, the gate electrode 17 is formed on the drift region 12 via the thick insulating film 24 in the peripheral portion of the unit cell forming portion 10A of the MOSFET 10. In the unit cell formation portion 10 </ b> A of the MOSFET 10, the gate electrode 17 is formed across two adjacent source regions 13.

  In this way, as shown in FIG. 3, the first composed of the gate oxide film 16 and the thick film insulating film 24 is formed on the base region 14 sandwiched between the drift region 12 and the source region 13 and on the drift region 12. A gate electrode 17 made of a polycrystalline silicon film is formed through the insulating film 40. Next, an oxide film is formed as the interlayer insulating film 18 which is the second insulating film by, for example, the CVD method. The structure shown in FIG. 3 is obtained through the manufacturing steps as described above.

  FIG. 4 is a cross-sectional view showing a state where the formation of the drain electrode 19 is completed. After the interlayer insulating film 18 is formed as described above, photolithography and reactive ion etching (abbreviation: RIE) are performed. As a result, the gate oxide film 16 and the interlayer insulating film 18 of the unit cell formation portion 10A of the MOSFET 10 are partially etched to expose the surface of the n + type source region 13 and the surface of the p + contact region 15 partially. A contact hole 22 is formed. Further, the interlayer insulating film 18 around the unit cell forming portion 10A of the MOSFET 10 is partially etched to form a gate contact hole 23 that partially exposes the surface of the gate electrode 17.

  Next, a silicide film 28 is formed on the surface of the source region 13 exposed through the source contact hole 22. For example, a NiSi film is formed as the silicide film 28. The NiSi film is formed by, for example, depositing a Ni film by sputtering and performing a heat treatment at about 1000 ° C. to react the SiC surface, which is the surface of the source region 13 exposed in the source contact hole 22, with the Ni film. . Next, a metal film having a thickness of about 3 μm to 5 μm is formed on the interlayer insulating film 18 by, for example, sputtering so as to fill the source contact hole 22 and the gate contact hole 23. The metal film is, for example, an aluminum film. Next, the metal film is partially removed by photolithography and etching to form the external output source electrode 20 and the external output gate electrode 25.

  Next, a silicide film and a metal film are sequentially formed on the surface on the other side in the thickness direction of the SiC substrate 11 to form the drain electrode 19. As the silicide film, for example, a NiSi film is formed. The NiSi film is formed by, for example, depositing a Ni film by sputtering and performing a heat treatment at about 1000 ° C. to react the surface of the SiC substrate 11 with the Ni film. In this manner, a semiconductor element body including the external output source electrode 20, the external output gate electrode 25, and the drain electrode 19 is formed. The structure shown in FIG. 4 is obtained through the manufacturing steps as described above.

  FIG. 5 is a cross-sectional view showing a state in which the formation of the temperature sensor wiring part 31 and the temperature sensor electrode part 32 has been completed. After the external output source electrode 20 and the external output gate electrode 25 are formed, first, the upper insulating film 30 is formed on the external output source electrode 20 and the external output gate electrode 25. Upper insulating film 30 is formed to cover external output source electrode 20 and external output gate electrode 25 and interlayer insulating film 18 exposed between external output source electrode 20 and external output gate electrode 25. The upper insulating film 30 is, for example, a silicon oxide film or a silicon nitride film formed by a plasma CVD method. The upper insulating film 30 is not limited to this, but may be an inorganic or organic SOG (Spin On Glass) formed by applying a solution obtained by dissolving silanol in a solvent such as alcohol or an organic siloxane resin by a spin coating method. .

  Next, after forming a metal film on the upper insulating film 30, photolithography and etching are performed to partially remove the metal film, thereby forming the temperature sensor wiring part 31 and the temperature sensor electrode part 32. Thereby, the temperature sensor 41 is formed. The metal film to be the temperature sensor wiring part 31 and the temperature sensor electrode part 32 is a metal film made of one or more selected from, for example, aluminum, platinum, palladium, titanium, and tungsten. The structure shown in FIG. 5 is obtained through the manufacturing process as described above.

  FIG. 6 is a cross-sectional view showing a state where the formation of the protective film 33 and the back surface connection electrode 21 is completed. A polyimide film is formed as the protective film 33 on the temperature sensor wiring portion 31 and the temperature sensor electrode portion 32 formed as described above, for example, by spin coating. Next, photolithography and etching are performed to open portions of the temperature sensor output pad 34 and the source electrode output pad 35.

  In the portion of the temperature sensor output pad 34, the protective film 33 on the temperature sensor electrode portion 32 is opened by etching. A portion of the temperature sensor electrode portion 32 exposed through the sensor opening 42 formed in the protective film 33 becomes a temperature sensor output pad 34. In the portion of the source electrode output pad 35, the protective film 33 and the upper insulating film 30 on the external output source electrode 20 are opened by etching. A portion of the external output source electrode 20 exposed through the source opening 43 formed in the protective film 33 and the upper insulating film 30 becomes a source electrode output pad 35.

  Next, an Ni film as the first metal film 21a and an Au film as the second metal film 21b are sequentially formed on the drain electrode 19 formed on the other surface in the thickness direction of the SiC substrate 11, for example, by sputtering, A back connection electrode 21 made of a laminated film of nickel and gold is formed. The structure shown in FIG. 6 is obtained through the manufacturing steps as described above.

  The semiconductor device 1 shown in FIGS. 1 and 2 is manufactured through the manufacturing steps shown in FIGS. 3 to 6 as described above. Electrical connection to the outside of the semiconductor device 1 is performed by a wire bond method. Specifically, the wire is connected to the temperature sensor output pad 34, the source electrode output pad 35, and the gate electrode output pad 36, respectively. For example, a wire made of aluminum is used as the wire.

  In the semiconductor device 1, current flows from the source electrode 20 on one side in the thickness direction of the semiconductor substrate 11 to the drain electrode 19 on the other side in the thickness direction of the semiconductor substrate 11, so that the wire connected to the source electrode output pad 35 Compared with the wires connected to the other pads 34 and 36, a large current flows. Therefore, as a wire connected to the source electrode output pad 35, in order to prevent the wire from fusing due to a large current, for example, a plurality of wires having a relatively large diameter of about 200 μm to 400 μm are used, and the plurality of wires are used as the source electrode. Connect to output pad 35. Since almost no current flows through the gate electrode output pad 36 and the temperature sensor output pad 34, only one wire having a relatively thin diameter of 100 μm or less may be used as the wire, or the source electrode output pad 35 may be used. You may use the wire of the same diameter as the wire to connect.

  By connecting a wire to the source electrode output pad 35, wire bonding to the source electrode 20 is performed. The wire bonding to the source electrode 20 is preferably performed by connecting a plurality of wires to the entire source electrode 20 in order to disperse the current. However, there is a wire around the periphery of the source electrode 20 and the periphery of the gate electrode 17. Because it is difficult to connect the wire, do not connect the wire. Therefore, the source electrode output pad 35 only needs to be opened in a rectangular shape inside the source electrode 20 as shown in FIG. The region other than the source electrode output pad 35 of the source electrode 20 is a region that is not used for connection to the outside. The temperature sensor wiring portion 31 and the temperature sensor electrode portion 32 are formed on a region other than the source electrode output pad 35 of the source electrode 20, which is a region not used for connection of the source electrode 20.

  Next, a temperature detection method using the temperature sensor 41 of the present invention will be described. The temperature sensor wiring part 31 of the temperature sensor 41 is, for example, a metal wiring resistor of several tens Ω or more and several kΩ or less. The temperature sensor 41 detects the temperature by measuring the resistance between the two temperature sensor electrode portions 32 connected to both ends of the temperature sensor wiring portion 31. The resistance between the two temperature sensor electrode portions 32 is measured, for example, by passing a small constant current between the two temperature sensor electrode portions 32 and measuring the voltage between the two temperature sensor electrode portions 32.

  As a metal constituting the temperature sensor wiring part 31, a metal having a high temperature coefficient of resistance (abbreviation: TCR), which can be easily formed on the MOSFET 10 and whose characteristics are stable is used. Metal resistance increases with increasing temperature. For example, since the TCR of the platinum resistor is about 4000 ppm / ° C., when a 100Ω platinum resistor is used, the temperature sensor 41 has a sensitivity of 0.4Ω / ° C.

  A sensor output pad 34 that is an external output pad of each temperature sensor electrode section 32 is connected to a temperature detection circuit (not shown). The temperature detection circuit detects the temperature based on a voltage measured by passing a constant current between the two temperature sensor electrode portions 32. By connecting the sensor output pad 34 to the temperature detection circuit in this way, the temperature of the element, that is, the temperature of the MOSFET 10 in this embodiment can be monitored. Therefore, it is possible to configure a protection circuit that stops the operation of the MOSFET 10 when the temperature of the MOSFET 10 exceeds a predetermined temperature by using a signal output from the temperature detection circuit.

  Next, the operation of the protection circuit having a temperature detection function will be described. When an overcurrent flows through the MOSFET 10 and the temperature of the MOSFET 10 rises, the resistance between the two temperature sensor electrode portions 32 rises. When the temperature of the MOSFET 10 rises above a predetermined temperature that leads to destruction of the MOSFET 10, the resistance value between the two temperature sensor electrode portions 32 increases to a predetermined resistance value corresponding to the predetermined temperature. When it rises above this predetermined resistance value, the protection circuit stops the operation of the MOSFET 10, suppresses the temperature rise of the MOSFET 10, and prevents the MOSFET 10 from being destroyed.

  As described above, according to the semiconductor device 1 of the present embodiment, the temperature sensor 41 is made of a metal material and is made of a metal wiring resistor formed on the upper insulating film 30 on the source electrode 20. 31 and a temperature sensor electrode portion 32. In this structure, the ion implantation process, the mask process, and the like are reduced and the number of manufacturing processes is reduced as compared with the case where the temperature sensor is configured by a PN junction element or the like as in the prior art. That is, the number of manufacturing steps for forming the temperature sensor can be reduced. Thereby, the semiconductor device 1 can be manufactured with a relatively small number of manufacturing steps. Therefore, mass productivity can be improved and manufacturing cost can be reduced.

  Further, in the case of a temperature sensor constituted by a PN junction element using polysilicon as in the prior art, in order to reduce the number of manufacturing steps, a polysilicon film constituting the gate electrode 17 of the MOSFET 10 and a PN junction element The polysilicon film is formed in one process. In this case, the PN junction element needs to be formed in a region other than the unit cell formation portion 10A of the MOSFET 10, specifically, a region around the unit cell formation portion 10A. The output electrode of the PN junction element that is a temperature sensor also needs to be formed in a region other than the unit cell formation portion 10A of the MOSFET 10, specifically, a region around the unit cell formation portion 10A. This increases the chip size and increases the manufacturing cost. Although the gate electrode 17 of the MOSFET 10 can also serve as the polysilicon film of the PN junction element that is a temperature sensor, it is necessary to form a wiring for extracting a signal, which increases the chip size and increases the manufacturing cost. End up.

  On the other hand, according to the semiconductor device 1 of the present embodiment, the temperature sensor 41 is formed on a region other than the region where the source electrode output pad 35A of the source electrode 20 is formed. Even if it is built in, the chip size does not increase. That is, since the temperature sensor 41 can be provided without reducing the effective area of the MOSFET 10, the temperature sensor 41 can be provided without increasing the size in the present embodiment. Therefore, an increase in size and an increase in manufacturing cost due to the provision of the temperature sensor 41 can be suppressed.

  In addition, since the SiC semiconductor has higher heat resistance than Si, the heat generated by overcurrent destroys the metal wiring that constitutes each electrode of the unit cell formation portion 10A of the MOSFET 10. As described above, since current flows from the source electrode 20 to the drain electrode 19, first, the metal wiring constituting the source electrode 20 is destroyed.

  When the temperature sensor is configured with a PN junction element using polysilicon as in the prior art, the temperature sensor is a region other than the unit cell formation portion 10A of the MOSFET 10, specifically, the periphery of the unit cell formation portion 10A. It is necessary to form in the region. Therefore, detection of heat generation is delayed, and detection of abnormality such as overheating is delayed.

  On the other hand, according to the semiconductor device 1 of the present embodiment, since the temperature sensor 41 is formed on the upper insulating film 30 on the source electrode 20, it is possible to quickly detect the heat generation of the source electrode 20. Can do. As a result, an abnormality such as overheating of the source electrode 20 can be detected earlier than in the prior art. As described above, the source electrode 20 is a portion in the MOSFET 10 that is easily broken by heat generation. In the present embodiment, the abnormality of the source electrode 20 can be detected earlier than in the prior art, so that the destruction of the MOSFET 10 due to heat generation can be prevented more reliably. Therefore, reliability can be improved.

<Second Embodiment>
FIG. 7 is a plan view showing a semiconductor device 1A according to the second embodiment of the present invention. Since the semiconductor device 1A of the present embodiment is similar in configuration to the semiconductor device 1 of the first embodiment described above, the same reference numerals are given to corresponding portions, and the first embodiment is described. The description common to the form is omitted.

  In the semiconductor device 1A of the present embodiment, the MOSFET 10 is formed on the SiC substrate 11 in the same manner as the semiconductor device 1 of the first embodiment described above. The external output pad of the semiconductor device 1A includes a drain electrode formed on the entire surface on the other side in the thickness direction of the SiC substrate 11, a source electrode output pad 35A formed on the one side in the thickness direction of the SiC substrate 11, and a gate electrode output pad. 36 and two temperature sensor output pads 34.

  In the first embodiment, the source opening 43 that defines the source electrode output pad 35 is one opening that is formed large inside the source electrode 20, but in the semiconductor device 1A of the present embodiment, The source opening 51 defining the source electrode output pad 35A is divided into nine 3 × 3. In other words, the source electrode output pad 35A is divided into nine parts. Hereinafter, each divided portion of the source electrode output pad 35A is referred to as a pad portion 50.

  Each pad portion 50 of the source electrode output pad 35 </ b> A is a part of the source electrode 20 and is exposed through each source opening 51. The pad portions 50 are arranged in a matrix. In the present embodiment, nine pad portions 50 are arranged in three rows of three. A wire connected to the source electrode 20 is connected to each pad portion 50. Each pad portion 50 is connected to one or more wires.

  Similar to the temperature sensor 41 in the first embodiment, the temperature sensor 41A includes a temperature sensor wiring portion 31A and a temperature sensor electrode portion 32. The temperature sensor wiring portion 31A is formed of a metal wiring resistor, similarly to the temperature sensor wiring portion 31 in the first embodiment. In the present embodiment, the temperature sensor wiring portion 31A is disposed on the upper insulating film 30 between the source openings 51 that define the pad portion 50 of the source electrode output pad 35A. More specifically, the temperature sensor wiring portion 31 </ b> A is disposed so as to surround each source opening 51. In a portion where the columns of the source openings 51 are adjacent, the temperature sensor wiring portion 31 </ b> A is disposed between the two adjacent columns of the source openings 51. More specifically, the wiring resistor constituting the temperature sensor wiring portion 31 </ b> A exits from one temperature sensor electrode portion 32, bends along each row of the source openings 51, and the other temperature sensor electrode portion 32. To reach.

  Since the manufacturing method and operation of semiconductor device 1A in the present embodiment are the same as those in the first embodiment, description thereof will be omitted. Also in the present embodiment, as in the first embodiment, the temperature sensor 41A is made of a metal material and is formed of a metal wiring resistor formed on the upper insulating film 30 on the source electrode 20. It has a structure constituted by the part 31A and the temperature sensor electrode part 32.

  In the temperature sensor 41A having this structure, as with the temperature sensor 41 in the first embodiment, compared to the case where the temperature sensor is configured with a PN junction element or the like as in the prior art, an ion implantation process, a mask process, and the like. And the number of manufacturing processes is reduced. As a result, the semiconductor device 1A can be manufactured with a relatively small number of manufacturing steps, so that mass productivity can be improved and the manufacturing cost can be reduced.

  Further, according to the semiconductor device 1A of the present embodiment, the temperature sensor 41A is on a region other than the region where the source electrode output pad 35A of the source electrode 20 is formed, like the temperature sensor 41 in the first embodiment. Therefore, even if the temperature sensor 41A is built in, the chip size does not increase. Therefore, since the temperature sensor 41A can be provided without increasing the size, an increase in size and an increase in manufacturing cost due to the provision of the temperature sensor 41A can be suppressed.

  In addition, since the SiC semiconductor has higher heat resistance than Si, the heat generated by overcurrent first destroys the metal wiring constituting each electrode of the unit cell formation portion 10A of the MOSFET 10, particularly the metal wiring constituting the source electrode 20. The According to the semiconductor device 1A of the present embodiment, the temperature sensor 41A is formed on the upper insulating film 30 on the source electrode 20 as in the first embodiment described above, so that the breakdown due to heat generation is prevented. Heat generation of the source electrode 20 that is likely to occur can be detected quickly. As a result, an abnormality such as overheating of the source electrode 20 can be detected earlier than in the prior art. Therefore, as compared with the prior art, destruction of the MOSFET 10 due to heat generation can be prevented more reliably, and the reliability can be improved.

  In the present embodiment, the temperature sensor wiring portion 31A is disposed on the upper insulating film 30 between the divided source openings 51, so that heat is generated regardless of where the source electrode 20 generates heat. Can be detected quickly. Therefore, since an abnormality such as overheating can be detected more reliably, the semiconductor device 1A can be more reliably prevented from being destroyed.

<Third Embodiment>
FIG. 8 is a plan view showing a semiconductor device 1B according to the third embodiment of the present invention. Since the semiconductor device 1B of the present embodiment is similar in configuration to the semiconductor device 1 of the first embodiment and the semiconductor device 1A of the second embodiment, the same reference is made to corresponding portions. The reference numerals are used to omit the description common to the first and second embodiments.

  In the semiconductor device 1B of the present embodiment, the source opening 51 that defines the source electrode output pad 35A is divided into 9 × 3 × 3, similarly to the semiconductor device 1A of the second embodiment described above. . A wire connected to the source electrode 20 is connected to each pad portion 50 divided into nine. Each pad portion 50 is connected to one or more wires.

  Similar to the temperature sensors 41 and 41A in the first and second embodiments, the temperature sensor 41B includes a temperature sensor wiring part 31B and a temperature sensor electrode part 32. Similar to the temperature sensor wiring portion 31A in the second embodiment, the temperature sensor wiring portion 31B is formed of a metal wiring resistor, and between the source openings 51 that define the pad portion 50 of the source electrode output pad 35A. It is disposed on the upper insulating film 30. In the second embodiment described above, the temperature sensor wiring portion 31A is disposed almost uniformly on the upper insulating film 30 between the source openings 51, whereas in the present embodiment, a certain specific The temperature sensor wiring part 31B is arranged concentrated on the area. FIG. 8 shows an arrangement example in which the temperature sensor wiring portion 31B is concentrated on the upper insulating film 30 around the source opening 51 that defines the pad portion 50 at the center of the source electrode 20. .

  Since the manufacturing method and operation of the semiconductor device 1B in the present embodiment are the same as those in the first embodiment, description thereof is omitted. Also in the present embodiment, as in the first embodiment, the temperature sensor 41B is made of a metal material and is made of a metal wiring resistor formed on the upper insulating film 30 on the source electrode 20. The structure is composed of the part 31B and the temperature sensor electrode part 32.

  In the temperature sensor 41B having this structure, as in the case of the temperature sensors 41 and 41A in the first and second embodiments, the ion implantation is performed as compared with the case where the temperature sensor is configured by a PN junction element or the like as in the prior art. Processes and mask processes are reduced, and the number of manufacturing processes is reduced. As a result, the semiconductor device 1B can be manufactured with a relatively small number of manufacturing steps, so that mass productivity can be improved and manufacturing cost can be reduced.

  Further, according to the semiconductor device 1B of the present embodiment, the temperature sensor 41B is formed with the source electrode output pad 35A of the source electrode 20 in the same manner as the temperature sensors 41 and 41A in the first and second embodiments. Since it is formed on a region other than the region, the chip size does not increase even if the temperature sensor 41B is incorporated. Therefore, since the temperature sensor 41B can be provided without increasing the size, an increase in size and an increase in manufacturing cost due to the provision of the temperature sensor 41B can be suppressed.

  In addition, since the SiC semiconductor has higher heat resistance than Si, the heat generated by overcurrent first destroys the metal wiring constituting each electrode of the unit cell formation portion 10A of the MOSFET 10, particularly the metal wiring constituting the source electrode 20. The According to the semiconductor device 1B of the present embodiment, since the temperature sensor 41B is formed on the upper insulating film 30 on the source electrode 20 as in the first and second embodiments described above, heat is generated. It is possible to quickly detect the heat generation of the source electrode 20 that is liable to be destroyed by. As a result, an abnormality such as overheating of the source electrode 20 can be detected earlier than in the prior art, so that the destruction of the MOSFET 10 due to heat generation can be prevented more reliably. Therefore, reliability can be improved.

  In the present embodiment, the temperature sensor wiring portion 31 </ b> B is disposed so as to concentrate on the upper insulating film 30 around the source opening 51 that defines the pad portion 50 at the center of the source electrode 20. As a result, when the semiconductor device 1B has a structure or operating condition in which heat is likely to occur around the pad portion 50 at the center of the source electrode 20, it generates heat compared to the second embodiment described above. It can be detected with high sensitivity, and abnormalities such as overheating can be detected with high sensitivity. Therefore, destruction of the semiconductor device 1B can be prevented more reliably.

  8 shows an example in which the temperature sensor wiring portion 31B is concentrated on the upper insulating film 30 around the source opening 51 that defines the pad portion 50 at the center of the source electrode 20, but the temperature sensor wiring is shown. The arrangement of the part 31B is not limited to this. Depending on the operating conditions and structure of the semiconductor device 1B, and the number and connection positions of wires connected to the source electrode output pad 35A, heat is generated in other regions such as the peripheral portion, the upper portion or the lower portion than the central portion of the source electrode 20. May occur easily. In this case, it is preferable that the temperature sensor wiring part 31B is arranged in a concentrated manner on the upper insulating film 30 on a region where heat generation is likely to occur. As a result, an abnormality in a region where heat generation is likely to occur can be detected with high sensitivity, so that destruction of the semiconductor device can be prevented more reliably.

  In the second and third embodiments described above, an example is shown in which the source opening 51 that defines the source electrode output pad 35A is divided into nine 3 × 3. However, the source opening 51 is divided. The state is not limited to this. For example, any division such as 4 × 2 × 2 or 15 × 3 × 5 may be used.

  In the first to third embodiments described above, the MOSFET 10 is an n-channel MOSFET, but may be a p-channel MOSFET by inverting the polarity of the dopant.

  1, 1A, 1B Semiconductor device, 10 MOSFET, 11 SiC substrate, 12 drift region, 13 source region, 14 base region, 15 p + contact region, 16 gate oxide film, 17 gate electrode, 18 interlayer oxide film, 19 drain electrode, 20 source electrode, 21 back surface connection electrode, 22 source contact hole, 23 gate contact hole, 24 thick film insulating film, 25 external output gate electrode, 30 upper layer insulating film, 31, 31A, 31B temperature sensor wiring section, 32 temperature Sensor electrode unit, 33 protective film, 34 temperature sensor output pad, 35, 35A source electrode output pad, 36 gate electrode output pad, 41, 41A, 41B temperature sensor.

Claims (4)

A semiconductor element comprising an external output electrode connected to the outside, and an insulating film covering the external output electrode;
A temperature sensor for detecting the temperature of the semiconductor element;
The temperature sensor includes a wiring-like temperature sensor wiring portion made of a metal material, and a temperature sensor electrode portion made of a metal material, connected to both ends of the temperature sensor wiring portion, and connected to the outside.
The temperature sensor wiring portion and the temperature sensor electrode portion are provided on the insulating film of the semiconductor element and on a region of the external output electrode other than a region where an electrode pad connected to the outside is formed. A semiconductor device. The electrode pad includes a plurality of pad portions exposed through a plurality of openings formed in the insulating film,
The semiconductor device according to claim 1, wherein the temperature sensor wiring portion is disposed on the insulating film between the openings.   3. The semiconductor device according to claim 2, wherein the temperature sensor wiring portion is concentrated on a part of the insulating film between the openings. A method for manufacturing a semiconductor device comprising a semiconductor element provided on a semiconductor substrate and a temperature sensor for detecting the temperature of the semiconductor element,
Forming a semiconductor element body including an external output electrode connected to the outside on the semiconductor substrate;
Forming an insulating film so as to cover the external output electrode, and forming the semiconductor element;
Forming a metal film made of a metal material on a region of the external output electrode other than a region of the external output electrode where an electrode pad connected to the outside is formed;
By partially removing the metal film, a temperature sensor wiring portion having a wiring shape and a temperature sensor electrode portion connected to both ends of the temperature sensor wiring portion and connected to the outside are formed, and the temperature And a step of forming a sensor.

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