Patent Publication Number: US-2023143787-A1

Title: Semiconductor device and manufacturing method of semiconductor device

Description:
The contents of the following Japanese patent application(s) are incorporated herein by reference: 
     NO. 2021-182858 filed in JP on Nov. 9, 2021 
     BACKGROUND 
     1. Technical Field 
     The present invention relates to a semiconductor device and a manufacturing method of the semiconductor device. 
     2. Related Art 
     Conventionally, there is known a technique of providing a temperature sensor on a semiconductor substrate on which a semiconductor element such as a metal oxide semiconductor field effect transistor (MOSFET) is formed (see, for example, Patent Documents 1 and 2).
     Patent Document 1: Japanese Patent Application Publication No. 7-153920   Patent Document 2: Japanese Patent Application Publication No. 2010-129707   

    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    illustrates an example of a top view of a semiconductor device  100  according to an example. 
         FIG.  2    illustrates an example of an XZ cross-sectional view of the semiconductor device  100 . 
         FIG.  3 A  illustrates an example of a top view of a temperature sensing unit  178  according to the example. 
         FIG.  3 B  illustrates an example of a cross-sectional view taken along line A-A′ of  FIG.  3 A . 
         FIG.  3 C  illustrates an example of a cross-sectional view taken along line B-B′ of  FIG.  3 A . 
         FIG.  3 D  illustrates an example of an equivalent circuit of the semiconductor device  100 . 
         FIG.  4 A  illustrates a top view of a temperature sensing diode portion according to a comparative example. 
         FIG.  4 B  illustrates an equivalent circuit of a semiconductor device according to the comparative example. 
         FIG.  5 A  illustrates temperature dependency of a forward voltage of a temperature sensing diode portion  173 . 
         FIG.  5 B  illustrates temperature dependency of polysilicon resistances of a P type and an N type. 
         FIG.  5 C  illustrates the temperature dependency of the forward voltage of the temperature sensing diode portion  173  connected to a resistance portion of the P type. 
         FIG.  5 D  illustrates the temperature dependency of the forward voltage of the temperature sensing diode portion  173  connected to a resistance portion of the N type. 
         FIG.  6 A  illustrates another example of the top view of the temperature sensing unit  178  according to the example. 
         FIG.  6 B  illustrates another example of the equivalent circuit of the semiconductor device  100 . 
         FIG.  6 C  illustrates another example of the top view of the temperature sensing unit  178  according to the example. 
         FIG.  7 A  illustrates still another example of the top view of the temperature sensing unit  178  according to the example. 
         FIG.  7 B  illustrates an example of a cross-sectional view taken along line B-B′ of  FIG.  7 A . 
         FIG.  7 C  illustrates another example of the cross-sectional view taken along line B-B′ of  FIG.  7 A . 
         FIG.  7 D  illustrates still another example of the cross-sectional view taken along line B-B′ of  FIG.  7 A . 
         FIG.  7 E  illustrates still another example of the cross-sectional view taken along line B-B′ of  FIG.  7 A . 
         FIG.  8 A  illustrates another example of the top view of the temperature sensing unit  178  according to the example. 
         FIG.  8 B  illustrates another example of the equivalent circuit of the semiconductor device  100 . 
         FIG.  9 A  illustrates another example of the top view of the temperature sensing unit  178  according to the example. 
         FIG.  9 B  illustrates another example of the equivalent circuit of the semiconductor device  100 . 
         FIG.  10 A  illustrates an example of a top view of a semiconductor device  200  according to the example. 
         FIG.  10 B  illustrates an example of an XZ cross-sectional view of the semiconductor device  200 . 
         FIG.  11 A  illustrates an example of a manufacturing method of the semiconductor device  100 . 
         FIG.  11 B  illustrates an example of the manufacturing method of the semiconductor device  100 . 
         FIG.  12    illustrates another example of the manufacturing method of the semiconductor device  100 . 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Hereinafter, the invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to claims. In addition, not all combinations of features described in the embodiments are essential to the solution of the invention. 
     As used in the present specification, one side in a direction parallel to a depth direction of a semiconductor substrate is referred to as “front” or “upper” and the other side is referred to as “back” or “lower”. One surface of two principal surfaces of a substrate, a layer, or other member is referred to as an upper surface, and the other surface is referred to as a lower surface. “Front”, “upper”, “back”, and “lower” directions are not limited to a direction of gravity, or directions in which a semiconductor device is mounted. 
     In the present specification, technical matters may be described using orthogonal coordinate axes of an X axis, a Y axis, and a Z axis. The orthogonal coordinate axes merely specify relative positions of components, and do not limit a particular direction. For example, the Z axis is not limited to indicate the height direction with respect to the ground. Note that a +Z axis direction and a −Z axis direction are directions opposite to each other. When the Z axis direction is described without describing the signs, it means that the direction is parallel to the +Z axis and the −Z axis. In addition, in the present specification, viewing from the +Z axis direction may be referred to as a top view. 
     In the present specification, a case where a term such as “same” or “equal” is mentioned may include a case where an error due to a variation in manufacturing or the like is included. The error is, for example, within 10%. 
     In the present specification, a conductivity type of doping region where doping has been carried out with an impurity is described as a P type or an N type. Note that each conductivity type of each doping region may be the opposite polarity. In addition, in the present specification, the description of a P+ type or an N+ type means a higher doping concentration than that of the P type or the N type, and the description of a P-type or an N−type means a lower doping concentration than that of the P type or the N type. 
     In the present specification, the doping concentration refers to the concentration of impurities activated as donors or acceptors. In the present specification, the concentration difference between the donor and the acceptor may be set as the higher concentration of the donor or the acceptor. The concentration difference can be measured by capacitance-voltage profiling (CV profiling). In addition, the carrier concentration measured by spreading resistance profiling method (SR) may be set as the donor or acceptor concentration. In addition, in a case where the concentration distribution of the donor or acceptor has a peak, the peak value may be set as the concentration of the donor or acceptor in the region. In a case where the concentration of the donor or acceptor in the region where the donor or acceptor is present is approximately uniform or the like, the average value of the donor concentration or acceptor concentration in the region may be set as the donor concentration or acceptor concentration. 
       FIG.  1    illustrates an example of a top view of a semiconductor device  100  according to an example. The semiconductor device  100  includes a semiconductor substrate  10 , a gate pad  50 , a current sensing pad  172 , a temperature sensing unit  178 , and an anode pad  174  and a cathode pad  176  electrically connected to the temperature sensing unit  178 . 
     The semiconductor substrate  10  has an end side  102 . In the present specification, a direction of one end side  102 - 1  of the semiconductor substrate  10  in the top view of  FIG.  1    is defined as an X axis, and a direction perpendicular to the X axis is defined as a Y axis. In the present example, the X axis is taken in the direction of the end side  102 - 1 . In addition, a direction perpendicular to an X axis direction and a Y axis direction and forming a right-handed system is referred to as a Z axis direction. The temperature sensing unit  178  of the present example is provided in the +Z axis direction of the semiconductor substrate  10 . 
     The semiconductor substrate  10  is made of a semiconductor material such as silicon semiconductor or a compound semiconductor. In the semiconductor substrate  10 , a side on which the temperature sensing unit  178  is provided is referred to as a front surface, and a surface on the opposite side is referred to as a back surface. In the present specification, a direction connecting the front surface and the back surface of the semiconductor substrate  10  is referred to as a depth direction. The semiconductor substrate  10  of the present example has a substantially rectangular shape on the front surface, but may have a different shape. 
     The semiconductor substrate  10  has an active portion  120  on the front surface. The active portion  120  is a region through which a main current flows in the depth direction between the front surface and the back surface of the semiconductor substrate  10  when the semiconductor device  100  is turned on. A gate conductive portion  44 , which will be described below, of the active portion  120  is connected to the gate pad  50  by a gate runner. 
     The active portion  120  may be provided with a transistor portion  70  such as a metal oxide semiconductor field effect transistor (MOSFET). 
     The semiconductor device  100  has a well region  130  of the P type outside the active portion  120  on the front surface. The semiconductor device has an edge termination structure portion on the further outside. The edge termination structure portion includes, for example, a guard ring and a field plate that are annularly provided to surround the active portion  120 , and a structure that is a combination of the guard ring and the field plate. 
     The temperature sensing unit  178  may be arranged in a wide portion provided near the center of the front surface of the semiconductor substrate  10 . The active portion  120  is not provided in the wide portion. Integration of the active portion  120  of the semiconductor substrate  10  causes the central portion of the semiconductor substrate  10  to be easily heated by heat generated from a switching element formed in the active portion  120 . Providing the temperature sensing unit  178  in the wide portion near the center allows for monitoring of the temperature of the transistor portion  70 . This can prevent the transistor portion  70  from being overheated beyond a junction temperature Tj which is a normal operating temperature range. 
     The temperature sensing unit  178  has a plurality of temperature sensing diode portions to be described below. The temperature sensing diode portion includes an anode wiring  180  electrically connected to an anode portion and a cathode wiring  182  electrically connected to a cathode portion. The anode wiring  180  and the cathode wiring  182  are wirings containing metal such as aluminum or an alloy containing aluminum. 
     The anode pad  174  and the cathode pad  176  are provided in an outer peripheral region of the active portion  120 . The anode pad  174  is connected to the temperature sensing unit  178  via the anode wiring  180 . The cathode pad  176  is connected to the temperature sensing unit  178  via the cathode wiring  182 . In  FIG.  1   , the anode pad  174  and the cathode pad  176  are provided to be arranged side by side along an end side  102 - 3 , and the anode wiring  180  and the cathode wiring  182  extend in the X axis direction. The anode pad  174  and the cathode pad  176  are electrodes containing metal such as aluminum or an alloy containing aluminum. 
     The current sensing pad  172  is provided in the outer peripheral region of the active portion  120 . The current sensing pad  172  may be provided to be aligned with the gate pad  50 , the anode pad  174 , and the cathode pad  176  along the Y axis direction (the end side  102 - 3  in  FIG.  1   ). The current sensing pad  172  is electrically connected to a current sensing unit  110 . The current sensing pad  172  is an example of a front surface electrode. The current sensing unit  110  has a structure similar to that of the transistor portion  70  of the active portion  120 , and simulates the operation of the transistor portion  70 . A current proportional to the current flowing through the transistor portion  70  flows through the current sensing unit  110 . This allows the current flowing through the transistor portion  70  to be monitored. 
     The current sensing unit  110  is provided with a gate trench portion. The gate trench portion of the current sensing unit  110  is electrically connected to the gate runner. Unlike the transistor portion  70 , the gate trench portion may have a portion where a source region  12  to be described below is not provided. 
       FIG.  2    illustrates an example of an XZ cross-sectional view of the semiconductor device  100 .  FIG.  2    illustrates an example of an XZ cross-sectional view of an element structure in the transistor portion  70  of the active portion  120 . The transistor portion  70  may be provided on the entire surface of the active portion  120  of the present example. 
     The transistor portion  70  has a plurality of gate trench portions  40  on the front surface  21  of the semiconductor substrate  10 . In addition, the semiconductor substrate  10  has a mesa portion  60  between the plurality of trench portions. The mesa portion  60  is connected to a source electrode  52  via a contact hole  54 . 
     The gate trench portion  40  includes the gate conductive portion  44  composed of a conductor such as metal, and a gate insulating film  42 . The gate conductive portion  44  is insulated from the source electrode  52  by an interlayer insulating film  38 . The gate conductive portion  44  is electrically connected to the gate pad  50  by the gate runner and set to have a gate potential. The gate conductive portion  44  corresponds to the gate electrode of the transistor portion  70 . As an example, the gate potential may be higher than a source potential. 
     The transistor portion  70  includes, in order from the front surface  21  side of the semiconductor substrate  10 , a source region  12  of a first conductivity type, a base region  14  of a second conductivity type, a drift region  18  of the first conductivity type, and a drain region  22  of the first conductivity type. The source region  12  may be provided over the entire active portion  120  on the front surface  21  of the semiconductor substrate  10  and provided in contact with the gate trench portion  40 . The base region  14  may be exposed to the front surface  21  between adjacent source regions  12  in the active portion  120 . As a result, the base region  14  and the source region  12  are connected to the source electrode  52  via the contact hole  54 . 
     In addition, in the mesa portion  60 , a contact region (not illustrated) of the second conductivity type may be provided between the source regions  12  adjacent to each other with the base region  14  interposed therebetween, and the contact region and the source electrode  52  may be connected to the source electrode  52  via the contact hole  54 . 
     As an example, the source region  12  has an N+ type polarity. That is, in the present example, the first conductivity type is the N type, and the second conductivity type is the P type. However, the first conductivity type may be the P type, and the second conductivity type may be the N type. In this case, each of the conductivity types of the substrate, the layer, the region, and the like in each example is of the opposite polarity. 
     The base region  14  of the present example has a P type polarity. When the gate conductive portion  44  is set to have the gate potential, electrons are attracted toward the gate trench portion  40  in the base region  14 . A channel of the N type is formed in a region of the base region  14  in contact with the gate trench portion  40 , and is driven as a transistor. 
     A drift region  18  of the N−type is provided below the base region  14 . A drain region  22  of the N+ type is provided below the drift region  18 . 
     The lower surface of the drain region  22  corresponds to the back surface  23  of the semiconductor substrate  10 . The drain electrode  24  is provided on the back surface  23  of the semiconductor substrate  10 . The drain electrode  24  is formed of a conductive material such as metal, or provided by stacking conductive materials such as metal. 
       FIG.  3 A  illustrates an example of a top view of the temperature sensing unit  178  according to the example. The temperature sensing unit  178  of the present example is provided above the front surface  21  of the semiconductor substrate  10 . The temperature sensing unit  178  includes a temperature sensing diode portion  173  connected in series, and a resistance portion  179  of the N type electrically connected to the temperature sensing diode portion  173 . 
     The temperature sensing diode portion  173  includes an anode portion  175  of the P type and a cathode portion  177  of the N type coupled (joined) to the anode portion  175 . The anode portion  175  may be polysilicon doped with boron (B). The cathode portion  177  may be polysilicon doped with arsenic (As), phosphorus (P), or the like. The doping concentration of the anode portion  175  and the cathode portion  177  may be greater than or equal to 1E18 cm −3  and less than 1E20 cm −3 . The anode portion  175  and the cathode portion  177  have substantially the same dimensions. In  FIG.  3 A , four temperature sensing diode portions  173  are connected in series along the X axis direction. 
     The resistance portion  179  of the present example is polysilicon of the N type. The resistance portion  179  may be polysilicon doped with arsenic (As), phosphorus (P), or the like. The doping concentration of the resistance portion  179  may be greater than or equal to 1E18 cm −3  and less than 1E20 cm −3 . 
     The doping concentration of the resistance portion  179  of the present example is equal to or less than the doping concentration of the cathode portion  177 . The doping concentration of the resistance portion  179  may be the same as the doping concentration of the cathode portion  177 . 
     The resistance portion  179  of the present example is provided between the cathode wiring  182  and the temperature sensing diode portion  173 , and is connected in series with the temperature sensing diode portion  173 . The resistance portion  179  has substantially the same dimensions as the anode portion  175  and the cathode portion  177 . 
     A connection portion  181  for connecting the temperature sensing diode portion  173  and the resistance portion  179  adjacent to each other is provided above the temperature sensing unit  178 . In  FIG.  3 A , the connection portion  181  is provided above the vicinity of the end portions of the temperature sensing diode portion  173  and the resistance portion  179  in the −Y axis direction. The connection portion  181  is a member containing metal such as aluminum or an alloy containing aluminum. 
     The temperature sensing diode portions  173  and the resistance portion  179  are connected to the connection portions  181  via contact holes  56  provided to penetrate interlayer insulating film  38 , and are connected to each other via the connection portions  181 . Note that the interlayer insulating film  38  is omitted in  FIG.  3 A . 
     The temperature sensing unit  178  is connected to each of the anode pad  174  and the cathode pad  176  via the anode wiring  180  and the cathode wiring  182 . In  FIG.  3 A , the anode wiring  180  is connected to the anode portion  175  of the temperature sensing diode portion  173  farthest from the anode pad  174  (in +X axis direction) via the contact hole  54  provided to penetrate the interlayer insulating film  38 . In addition, the cathode wiring  182  is connected to the resistance portion  179  via a contact hole  55  provided to penetrate the interlayer insulating film  38 , and the resistance portion  179  is connected to the cathode portion  177  of the closest temperature sensing diode portion  173  via the contact hole  56  and the connection portion  181 . 
       FIG.  3 B  illustrates an example of a cross-sectional view taken along line A-A′ of  FIG.  3 A . The cross-sectional view taken along line A-A′ is an XZ cross-sectional view passing through the anode wiring  180  and the temperature sensing unit  178 .  FIG.  3 C  illustrates an example of a cross-sectional view taken along line B-B′ of  FIG.  3 A . The cross-sectional view taken along line B-B′ is an XZ cross-sectional view passing through the cathode wiring  182  and the temperature sensing unit  178 . 
     The temperature sensing unit  178  of the present example is provided above the well region  130 . The anode portion  175  and the cathode portion  177  are arrayed on a surface parallel to the front surface  21  of the semiconductor substrate  10 . The resistance portion  179 , the anode portion  175 , and the cathode portion  177  of the present example are provided on the first insulating film  36  provided on the front surface  21  of the semiconductor substrate  10 , and the upper side and the side thereof are covered with the interlayer insulating film  38 . The first insulating film  36  may be formed of the same oxide film as the gate insulating film  42 . 
     The contact hole  54  and the contact hole  55  are positioned to be aligned with the contact hole  56  in the Y axis direction. In  FIG.  3 A , the contact hole  54 , the contact hole  55 , and the contact hole  56  are provided to be aligned in the extending direction of the cathode wiring  182 . 
       FIG.  3 D  illustrates an example of an equivalent circuit of the semiconductor device  100 .  FIG.  3 D  illustrates an example of an element structure of the active portion  120  and a circuit configuration of the temperature sensing unit  178  illustrated in  FIG.  3 A . Note that both of them are insulated by the interlayer insulating film  38 . The element structure of the active portion  120  in the present example is a MOSFET (metal oxide semiconductor field effect transistor). 
     A plurality of temperature sensing diode portions  173  and the resistance portion  179  in the present example are connected in series between the anode pad  174  and the cathode pad  176 . The temperature sensing diode portion  173  may be a Zener diode including the anode portion  175  and the cathode portion  177 . 
     The anode wiring  180  connects the anode pad  174  and the anode portion  175  of the temperature sensing diode portion  173 , and the cathode wiring  182  connects the cathode pad  176  and the resistance portion  179 . The resistance portion  179  of the present example is provided between the cathode wiring  182  and the temperature sensing diode portion  173 . 
     In the circuit between the anode pad  174  and the cathode pad  176 , the resistance of the metal wiring (the anode wiring  180 , the cathode wiring  182 , and the connection portion  181 ) is smaller by two order of magnitude than the resistance of polysilicon (the resistance portion  179 , the anode portion  175 , and the cathode portion  177 ). Accordingly, the resistance of this circuit depends substantially on the resistance of polysilicon. 
     The resistance of polysilicon depends on its dimensions and the doping concentration of impurities. In addition, as described above, the dimensions of the resistance portion  179 , the anode portion  175 , and the cathode portion  177  are substantially the same. In the temperature sensing unit  178  of the present example, the resistance value of an N type region is greater than the resistance value of a P type region. That is, the sum of the resistance values of the cathode portion  177  and the resistance portion  179  is greater than the resistance value of the anode portion  175 . 
       FIG.  4 A  illustrates a top view of a temperature sensing diode portion according to a comparative example. The configuration of the semiconductor device according to the comparative example is common to that of the semiconductor device  100  according to the example except that the resistance portion of the N type electrically connected to the temperature sensing diode portion is not provided. Therefore, in the description of the comparative example, the same reference numerals are given to elements whose configuration and function are common to those of the semiconductor device  100 , and the description thereof will be omitted. 
     In the comparative example, a plurality of temperature sensing diode portions  173  is connected in series. The plurality of temperature sensing diode portions  173  is connected to each of the anode pad  174  and the cathode pad  176  via the anode wiring  180  and the cathode wiring  182 . In  FIG.  4 A , the anode wiring  180  is connected to the anode portion  175  of the temperature sensing diode portion  173  farthest from the anode pad  174  (in +X axis direction) via the contact hole  54  provided to penetrate the interlayer insulating film  38 . In addition, the cathode wiring  182  is connected to the cathode portion  177  of the temperature sensing diode portion  173  closest to the cathode pad  176  (in −X axis direction) via the contact hole  55  provided to penetrate the interlayer insulating film  38 . 
       FIG.  4 B  illustrates an equivalent circuit of the semiconductor device according to the comparative example. In the comparative example, the resistance of the circuit between the anode pad  174  and the cathode pad  176  is substantially dependent on the resistance of the plurality of temperature sensing diode portions  173 . In addition, in the plurality of temperature sensing diode portions  173 , the resistance value of the N type region and the resistance value of the P type region are substantially the same. That is, the resistance value of the cathode portion  177  and the resistance value of the anode portion  175  are substantially the same. 
       FIG.  5 A  illustrates temperature dependency of a forward voltage of the temperature sensing diode portion  173 .  FIG.  5 A  illustrates a graph in which a horizontal axis represents a forward voltage V F [V], and a vertical axis represents a forward current I F [A]. The forward voltage V F  is a voltage that drops when the forward current I F  flows through the temperature sensing diode portion  173 . 
     The forward voltage V F  of the temperature sensing diode portion  173  formed of polysilicon has a characteristic of decreasing when the temperature increases and increasing when the temperature decreases, so-called negative temperature dependency. Assuming that a forward current at a reference temperature is I 0 [A] and a forward voltage at the reference temperature is V F1 [V], a forward voltage V F1L  for a forward current I 0  is less than V F1  in a region having a temperature higher than the reference temperature, and a forward voltage V F1H  for the forward current I 0  is greater than V F1  in a region having a temperature lower than the reference temperature. 
     A variation amount ΔV F  from the forward voltage V F1  is converted into a temperature change amount and monitored. When ΔV F  exceeds a predetermined threshold, it is determined that a heat generation amount exceeds an assured value. Note that since ΔV F  is generally as small as 0.6 to 0.8 V, a method of connecting a plurality of temperature sensing diode portions  173  in series and measuring a total value of ΔV F  to improve detection sensitivity is adopted. 
     In the method of measuring the total value of ΔV F  of the plurality of temperature sensing diode portions  173 , the measurement error included in each ΔV F  may be enlarged. On the other hand, in recent years, the semiconductor device  100  has been used in a hot region such as an engine room of a vehicle and in applications where highly accurate temperature detection is requested. Further, in view of an increasing request for safety, improvement in temperature detection accuracy is required in the semiconductor device  100 . 
       FIG.  5 B  illustrates temperature dependency of polysilicon resistances of the P type and the N type. In  FIG.  5 B , a vertical axis represents a relative value (a ratio where a resistance value at the reference temperature is 1) with respect to the resistance value at the reference temperature (room temperature), and a horizontal axis represents a graph of a temperature [K]. 
     As illustrated in  FIG.  5 B , in the polysilicon resistance of the P type (the legend is a circle and a square), the relative value of the reference temperature to the resistance value is proportional to the temperature. That is, in the polysilicon resistance of the P type, the resistance is proportional to the temperature, and has positive temperature dependency. In addition, when the polysilicon resistances of the P type having different resistances are compared with each other, the polysilicon resistance of the P type having a smaller resistance (the legend is a circle) has higher temperature dependency than the polysilicon resistance of the P type having a larger resistance (the legend is a square). Accordingly, the polysilicon resistance of the P type has temperature dependency opposite to the forward voltage V F  of the temperature sensing diode portion  173 . Herein, in the present example, the temperature dependency of the resistance due to a difference in impurity concentration is shown in polysilicon having the same shape. 
     On the other hand, the polysilicon resistance of the N type (the legend is a triangle) is inversely proportional to the temperature. That is, in the polysilicon resistance of the N type, the resistance is inversely proportional to the temperature, and has negative temperature dependency. Accordingly, the polysilicon resistance of the N type has the same temperature dependency as the forward voltage V F  of the temperature sensing diode portion  173 . 
       FIG.  5 C  illustrates the temperature dependency of the forward voltage of the temperature sensing diode portion  173  connected to a resistance portion of the P type.  FIG.  5 D  illustrates the temperature dependency of the forward voltage of the temperature sensing diode portion  173  connected to a resistance portion of the N type.  FIGS.  5 C and  5 D  illustrate graphs in which a horizontal axis represents the forward voltage V F [V], and a vertical axis represents the forward current I F [A]. Herein, the connection of the temperature sensing diode portion  173  to the resistance portion of the N type means that the cathode portion  177  of the temperature sensing diode portion  173  is connected to the resistance portion of the polysilicon of the N type having similar dimensions, for example, as illustrated in  FIG.  3 A . In addition, the connection of the temperature sensing diode portion  173  to the resistance portion of the P type means that, for example, conversely to  FIG.  3 A , the anode portion  175  of the temperature sensing diode portion  173  is connected to the resistance portion of the polysilicon of the P type having similar dimensions. 
     As described above, the polysilicon resistance of the P type has temperature dependency opposite to the forward voltage V F  of the temperature sensing diode portion  173 . Accordingly, as illustrated in  FIG.  5 C , in the temperature sensing diode portion  173  connected to the resistance portion of the P type, the gradient of V F -I F  is small in a region having a temperature higher than the reference temperature, and the gradient of V F -I F  is large in a region having a temperature lower than the reference temperature. Therefore, the variation amount ΔV F  of the forward voltage V F  in the forward current I 0  is less than ΔV F  of the temperature sensing diode portion  173  illustrated in  FIG.  5 A . 
     On the other hand, the polysilicon resistance of the N type has the same temperature dependency as the forward voltage V F  of the temperature sensing diode portion  173 . Accordingly, as illustrated in  FIG.  5 D , in the temperature sensing diode portion  173  connected to the resistance portion of the N type, the gradient of the V F  is large in a region having a temperature higher than the reference temperature, and the gradient of V F -I F  is small in a region having a temperature lower than the reference temperature. Therefore, the variation amount ΔV F  of the forward voltage V F  in the forward current I 0  is greater than ΔV F  of the temperature sensing diode portion  173  illustrated in  FIG.  5 A . 
     In this manner, the temperature sensing unit  178  of the present example has the resistance portion  179  of the N type having the same temperature dependency as the forward voltage V F  of the temperature sensing diode portion  173 , and since the resistance value of the N type region is larger than the resistance value of the P type region, the variation amount ΔV F  of the forward voltage V F  in the forward current I 0  increases, and the temperature detection accuracy can be improved. 
       FIG.  6 A  illustrates another example of the top view of the temperature sensing unit  178  according to the example.  FIG.  6 B  illustrates another example of the equivalent circuit of the semiconductor device  100 .  FIG.  6 B  illustrates an example of the equivalent circuit corresponding to the semiconductor device  100  including the temperature sensing unit  178  of  FIG.  6 A . In the description of  FIG.  6 A , the description of elements common to those of  FIG.  3 A  is omitted. 
     In  FIG.  6 A , the contact hole  54  and the contact hole  56  provided on the temperature sensing diode portion  173  are provided to be aligned in an extending direction (+X axis direction) of the cathode wiring  182 . In addition, the contact hole  55  and the contact hole  56  provided on the resistance portion  179  are provided to be arranged side by side in the extending direction (+X axis direction) of the anode wiring  180 . 
     The cathode wiring  182  is connected to the cathode portion  177  of the temperature sensing diode portion  173  closest to the cathode pad  176  via the contact hole  54 . In addition, the anode wiring  180  is connected to the resistance portion  179  via the contact hole  55 . 
     The resistance portion  179  is connected to the anode portion  175  of the temperature sensing diode portion  173  farthest from the anode pad  174  via the contact hole  56  and the connection portion  183 . The resistance portion  179  is provided between the anode wiring  180  and the temperature sensing diode portion  173 . 
     The connection portion  183  has an L shape, and has a portion extending in the extending direction (+X axis direction) of the anode wiring  180  and a portion extending from the anode wiring  180  side to the cathode wiring  182  side (−Y axis direction). 
       FIG.  6 B  illustrates an example of the equivalent circuit corresponding to the semiconductor device  100  including the temperature sensing unit  178  of  FIG.  6 A .  FIG.  6 B  illustrates an example of an element structure of the active portion  120  and a circuit configuration of the temperature sensing unit  178  illustrated in  FIG.  6 A . Note that both of them are insulated by the interlayer insulating film  38 . The element structure of the active portion  120  in the present example is a MOSFET (metal oxide semiconductor field effect transistor). 
     A plurality of temperature sensing diode portions  173  and the resistance portion  179  in the present example are connected in series between the anode pad  174  and the cathode pad  176 . The temperature sensing diode portion  173  may be a Zener diode including the anode portion  175  and the cathode portion  177 . 
     The cathode wiring  182  connects the cathode pad  176  and the cathode portion  177  of the temperature sensing diode portion  173 , and the anode wiring  180  connects the anode pad  174  and the resistance portion  179 . Although the present example is different from  FIG.  3 D  in that the resistance portion  179  is provided between the anode wiring  180  and the temperature sensing diode portion  173 , effects similar to those of  FIGS.  3 A to  3 D  can be obtained. 
       FIG.  6 C  illustrates another example of the top view of the temperature sensing unit  178  according to the example. The example of  FIG.  6 C  is different from  FIG.  6 A  in that the connection portion  183  has a rectangular shape. In  FIG.  6 C , the contact hole  54  and the contact hole  56 , which are provided on the temperature sensing diode portion  173 , except for a part thereof are provided to be aligned in the extending direction (+X axis direction) of the cathode wiring  182 . 
     Note that the contact hole  56  provided on the anode portion  175  of the temperature sensing diode portion  173  located at the farthest position from the anode wiring  180  is provided in the extending direction (+X axis direction) of the anode wiring  180 . In addition, the contact hole  55  and the contact hole  56  provided on the resistance portion  179  are provided to be arranged side by side in the extending direction (+X axis direction) of the anode wiring  180 . 
     The cathode wiring  182  is connected to the cathode portion  177  of the closest (+X axis direction) temperature sensing diode portion  173  via the contact hole  54 . In addition, the anode wiring  180  is connected to the resistance portion  179  via the contact hole  55 . The resistance portion  179  is connected to the anode portion  175  of the temperature sensing diode portion  173  farthest from the anode pad  174  via the contact hole  56  and the connection portion  183 . The resistance portion  179  is provided between the anode wiring  180  and the temperature sensing diode portion  173 . Also in the present example, the same effects as those in  FIGS.  3 A to  3 D  can be obtained. 
       FIG.  7 A  illustrates another example of the top view of the temperature sensing unit  178  according to the example. In the description of  FIGS.  7 A and  7 B , the description of elements common to those of  FIG.  3 A  is omitted. 
     In  FIG.  7 A , the resistance portion  179  is provided to be coupled to the cathode portion  177 . That is, the resistance portion  179  is provided integrally with the cathode portion  177  of the temperature sensing diode portion  173  closest to the cathode pad  176  (in −X axis direction). As a result, the X axis direction distance of the temperature sensing unit  178  is shortened, the area of the active portion  120  can be enlarged, and the number of the connection portions  181  and the contact holes  56  can be reduced. 
     In  FIG.  7 A , the contact hole  54 , the contact hole  55 , and the contact hole  56  are provided to be aligned in the extending direction of the cathode wiring  182  similarly to  FIG.  3 A , but may be provided to be aligned in the extending direction of the anode wiring line  180  similarly to  FIG.  6 A . 
       FIG.  7 B  illustrates an example of a cross-sectional view taken along line B-B′ of  FIG.  7 A . Similarly to the temperature sensing unit  178  of  FIG.  3 A , the temperature sensing unit  178  of the present example is provided on the first insulating film  36  provided on the front surface  21  of the semiconductor substrate  10  (see  FIG.  3 C ). 
       FIG.  7 C  illustrates another example of the cross-sectional view taken along line B-B′ of  FIG.  7 A . The semiconductor device  100  of the present example further includes a conductive layer  185  provided on the first insulating film  36  and a second insulating film  37  covering the conductive layer  185 , and the temperature sensing unit  178  is provided on the second insulating film  37 . 
     The second insulating film  37  may be an oxide film formed by thermal oxidation or a CVD method. The conductive layer  185  is polysilicon of the N type. The conductive layer  185  may be formed of the same doped polysilicon as a dummy conductive portion  34  and the gate conductive portion  44 . The doping concentration of the conductive layer  185  is 1E20 cm −3  or more. 
     In this manner, the conductive layer  185  is arranged between the first insulating film  36  and the second insulating film  37 , and a Z axis direction distance from the front surface  21  of the semiconductor substrate  10  to the lower end of the temperature sensing diode portion  173  increases. As a result, a capacitive component is formed below the temperature sensing diode portion  173 , and it is possible to prevent the temperature sensing diode portion  173  from being broken by static electricity or an overvoltage applied to the electrode. 
       FIG.  7 D  illustrates still another example of the cross-sectional view taken along line B-B′ of  FIG.  7 A . The semiconductor device  100  of the present example is common to that of  FIG.  7 C  in including the conductive layer  185  and the second insulating film  37 , but the conductive layer  185  has a plurality of regions which are arranged correspondingly to the temperature sensing diode portions  173  and the resistance portion  179  and divided from each other. 
     In this manner, by dividing the conductive layer  185 , even when any of the plurality of temperature sensing diode portions  173  is broken, the influence remains only in the relevant temperature sensing diode portion  173 , and short-circuiting of the other temperature sensing diode portions  173  can be prevented. 
       FIG.  7 E  illustrates still another example of the cross-sectional view taken along line B-B′ of  FIG.  7 A . The semiconductor device  100  of the present example is common to that of  FIG.  7 D  in including the conductive layer  185  and the second insulating film  37 , and in that the conductive layer  185  is divided into a plurality of regions. Note that, in the present example, the resistance portion  179  is provided not on the second insulating film  37  but on the first insulating film  36 . That is, in the present example, either of the divided regions of the conductive layer  185  may be used as the resistance portion  179 . In this manner, in a region where the conductive layer  185  also serves as the resistance portion  179 , the thickness in the Z axis direction can be reduced. 
     By reducing the thickness in the Z axis direction, the resistance in the region where the conductive layer  185  also serves as the resistance portion  179  increases, and the area of the resistance portion  179  can be reduced. In addition, in the region where the conductive layer  185  also serves as the resistance portion  179 , by reducing the length in the Y axis direction, the resistance is increased, and the area of the resistance portion  179  can be reduced. 
       FIG.  8 A  illustrates another example of the top view of the temperature sensing unit  178  according to the example.  FIG.  8 B  illustrates another example of the equivalent circuit of the semiconductor device  100 .  FIG.  8 B  illustrates an example of the equivalent circuit corresponding to the semiconductor device  100  including the temperature sensing unit  178  of  FIG.  8 A . In the description of  FIGS.  8 A and  8 B , the description of elements common to those of  FIG.  3 A  is omitted. 
     The resistance portion  179  of the present example includes an anode side resistance portion  179 A provided between the anode wiring  180  and the temperature sensing diode portion  173 , and a cathode side resistance portion  179 K provided between the cathode wiring  182  and the temperature sensing diode portion  173 . 
     The anode wiring  180  is connected to the anode side resistance portion  179 A via the contact hole  54 , and the anode side resistance portion  179 A is connected to the anode portion  175  of the temperature sensing diode portion  173  farthest from the anode pad  174  (in +X axis direction) via the contact hole  56  and the connection portion  181 . In addition, the cathode wiring  182  is connected to the cathode side resistance portion  179 K via the contact hole  55 , and the cathode side resistance portion  179 K is connected to the cathode portion  177  of the closest temperature sensing diode portion  173  via the contact hole  56  and the connection portion  181 . 
     The anode side resistance portion  179 A and the cathode side resistance portion  179 K may have the same doping concentration or different doping concentrations. The anode side resistance portion  179 A and the cathode side resistance portion  179 K may have the same dimension or different dimensions. In addition, in  FIG.  8 A , the anode side resistance portion  179 A is provided in the +X axis direction with respect to the cathode side resistance portion  179 K, but these positions may be reversed. 
       FIG.  9 A  illustrates another example of the top view of the temperature sensing unit  178  according to the example.  FIG.  9 B  illustrates another example of the equivalent circuit of the semiconductor device  100 .  FIG.  9 B  illustrates an example of the equivalent circuit corresponding to the semiconductor device  100  including the temperature sensing unit  178  of  FIG.  9 A . In the description of  FIGS.  9 A and  9 B , the description of elements common to those of  FIG.  3 A  is omitted. 
     The resistance portion  179  of the present example is provided between the temperature sensing diode portions  173 . That is, the resistance portions  179  are provided integrally with the cathode portions  177  of the temperature sensing diode portions  173 . As a result, the X axis direction distance of the temperature sensing unit  178  is shortened, the area of the active portion  120  can be enlarged, and the number of the connection portions  181  and the contact holes  56  can be reduced. 
     In the example of  FIGS.  8 A to  9 B , the conductive layer  185  and the second insulating film  37  as illustrated in  FIG.  7 C or  7 D  may be provided below the temperature sensing unit  178 . 
     In this manner, the temperature sensing unit  178  of the present example has the resistance portion  179  of the N type having the same temperature dependency as the forward voltage V F  of the temperature sensing diode portion  173 , and since the resistance value of the N type region is larger than the resistance value of the P type region, the variation amount ΔV F  of the forward voltage V F  in the forward current I 0  increases, and the temperature detection accuracy can be improved. 
     The temperature sensing unit  178  according to the above-described example includes the resistance portion  179  of the N type, but instead of this, metal such as aluminum or an alloy containing aluminum may be used as the resistance portion. In this case, the dimension (in particular, the length) of the resistance portion may be determined such that the total value of the resistances of the cathode portion  177  and the resistance portion becomes greater than the resistance of the anode portion  175 . Alternatively, instead of providing the resistance portion in the temperature sensing unit  178 , the extension lengths of the anode wiring  180  and the cathode wiring  182  may be increased. 
       FIG.  10 A  illustrates an example of a top view of a semiconductor device  200  according to an example. The present example is different from  FIG.  1    in that the transistor portion  70  including a transistor element such as an insulated gate bipolar transistor (IGBT) and a diode portion  80  including a diode element such as a freewheeling diode (FWD) are provided in the active portion  120 . 
     When the IGBT and the FWD are provided in the active portion  120 , the transistor portion  70  and the diode portion  80  form a reverse conducting IGBT (RC-IGBT). The active portion  120  may be a region in which at least one transistor portion  70  and at least one diode portion  80  are provided. 
     In the present example, in the active portion  120 , a symbol “I” is attached to a region where the transistor portion  70  is arranged, and a symbol “F” is attached to a region where the diode portion  80  is arranged. The transistor portion  70  and the diode portion  80  may be alternately arranged side by side in the X axis direction in each region of the active portion  120 . 
       FIG.  10 B  illustrates an example of an XZ cross-sectional view of the semiconductor device  200 .  FIG.  10 B  illustrates an example of an XZ cross-sectional view of the element structure in the transistor portion  70  and the diode portion  80  of the active portion  120 . 
     The transistor portion  70  has a plurality of dummy trench portions  30  and a plurality of gate trench portions  40  on the front surface  21  of the semiconductor substrate  10 , and the diode portion  80  includes a plurality of dummy trench portions  30 . In addition, the semiconductor substrate  10  has the mesa portion  60  which is a dopant diffusion region between the plurality of trench portions. The mesa portion  60  is connected to an emitter electrode  53  via the contact hole  54 . 
     The dummy trench portion  30  has a dummy insulating film  32  and the dummy conductive portion  34 . The dummy conductive portion  34  is electrically connected to the emitter electrode  53  via the contact hole and set to have an emitter potential. 
     The gate trench portion  40  includes the gate conductive portion  44  composed of a conductor such as metal and a gate insulating film  42 . The gate conductive portion  44  is insulated from the emitter electrode  53  by the interlayer insulating film  38 . The gate conductive portion  44  is electrically connected to the gate pad  50  by the gate runner and set to have a gate potential. The gate conductive portion  44  corresponds to the gate electrode of the transistor portion  70 . As an example, the gate potential may be higher than the emitter potential. 
     The transistor portion  70  includes, in order from the front surface  21  side of the semiconductor substrate  10 , an emitter region  13  of the first conductivity type, a base region  15  of the second conductivity type, a drift region  18  of the first conductivity type, and a collector region  25  of the second conductivity type. The emitter region  13  may be provided over the entire mesa portion  60  on the front surface  21  of the semiconductor substrate  10 , or may be provided only in a region close to the dummy trench portion  30  and the gate trench portion  40 . In a region of in the mesa portion  60  where the emitter region  13  is not provided, the base region  15  may be exposed to the front surface  21 . 
     In addition, the transistor portion  70  of the present example has an accumulation region  16  of the first conductivity type provided between the base region  15  and the drift region  18 . By providing the accumulation region  16 , the IE effect (Injection Enhancement effect) of carriers on the base region  15  can be improved, and an on-voltage can be reduced. Note that the accumulation region  16  may be omitted. 
     As an example, the emitter region  13  has an N+ type polarity. The base region  15  is different from the base region  14  of  FIG.  2    in that the base region has a P-type polarity. When the gate conductive portion  44  is set to have the gate potential, electrons are attracted toward the gate trench portion  40  in the base region  15 . A channel of the N type is formed in a region of the base region  15  in contact with the gate trench portion  40 , and is driven as a transistor. 
     In the diode portion  80 , the base region  15  of the P− type is provided on the front surface  21  side of the semiconductor substrate  10 . The diode portion  80  of the present example is not provided with the accumulation region  16 . In another example, the accumulation region  16  may also be provided in the diode portion  80 . 
     The drift region  18  of the N−type is provided below the accumulation region  16  in the transistor portion  70  and below the base region  15  in the diode portion  80 . In both the transistor portion  70  and the diode portion  80 , a buffer region  20  of the N type is provided under the drift region  18 . The buffer region  20  may function as a field stop layer that prevents a depletion layer extending from the lower surface of the base region  15  from reaching the collector region  25  of the P type and the cathode region  82  of the N+ type. 
     In the transistor portion  70 , the collector region  25  of the P type is provided below the buffer region  20 . In the diode portion  80 , the cathode region  82  of the N+ type is provided below the buffer region  20 . 
     The lower surfaces of the collector region  25  and the cathode region  82  correspond to the back surface  23  of the semiconductor substrate  10 . A collector electrode  26  is provided on the back surface  23  of the semiconductor substrate  10 . The collector electrode  26  is provided by a conductive material such as metal or by stacking conductive materials such as metal. 
     In the present example, the transistor portion  70  and the diode portion  80  are alternately arranged along the X axis direction, but the transistor portion  70  and the diode portion  80  may be alternately arranged along the Y axis direction. 
     Also in the semiconductor device  200  including the RC-IGBT in the active portion  120 , the temperature sensing unit  178  illustrated in  FIGS.  3 A,  3 B,  3 C,  6 A,  6 C,  7 A,  7 B,  7 C,  7 D,  7 E,  8 A, and  9 A  can be provided. In this case, in the temperature sensing unit  178 , the buffer region  20  is provided on the lower surface of the drift region  18 , and the collector region  25  is provided on the lower surface of the buffer region  20 . 
     The temperature sensing unit  178  can obtain the same effect as a case where the MOSFET is provided in the active portion  120 . Further, the same applies to a case where the active portion  120  includes an insulated gate bipolar transistor (IGBT). 
       FIGS.  11 A and  11 B  illustrate an example of a manufacturing method of the semiconductor device  100 . Herein, a step of forming the temperature sensing unit  178  in  FIG.  3 A  will be described. In step S 100 , the first insulating film  36  is formed on the front surface  21  of the semiconductor substrate  10  by thermal oxidation. A region where the temperature sensing unit  178  is formed may be a region where the well region  130  is provided on the front surface  21  of the semiconductor substrate  10 . 
     The first insulating film  36  may be formed of the same oxide film as the gate insulating film  42 . That is, the first insulating film  36  may be formed in the same step as the gate insulating film  42 . 
     In step S 102 , a polysilicon layer  170  for forming the temperature sensing unit  178  is formed on the first insulating film  36  by a CVD method. The polysilicon layer  170  may be non-doped polysilicon or polysilicon of the N type with a low doping concentration. 
     In step S 104 , a P type impurity such as boron (B) is ion-implanted from above the front surface  21  of the semiconductor substrate  10 . The P type impurity is ion-implanted into the entire surface of the polysilicon layer  170 . The doping concentration of the P type impurity may be greater than or equal to 1E18 cm −3  and less than 1E20 cm −3 . 
     Next, in step S 106 , a resist mask  190  is arranged on the polysilicon layer  170 , and an N type impurity is selectively ion-implanted from above the front surface  21  of the semiconductor substrate  10  by using the resist mask  190 . The N type impurity is arsenic (As), phosphorus (P), or the like. The doping concentration of the N type impurity may be greater than or equal to 1E18 cm −3  and less than 1E20 cm −3 . 
     A region where the resist mask  190  is arranged corresponds to the P type region that finally becomes the anode portion  175 . A region into which the N type impurity is ion-implanted corresponds to the N type region that finally becomes the cathode portion  177  or the resistance portion  179 . 
     The N type impurity is ion-implanted with a dimension (width) such that the resistance of the N type region is larger than the resistance of the P type region. Note that the implantation depth of the P type impurity implanted in the previous step S 104  is indicated by a broken line. 
     The doping concentration of the resistance portion  179  may be the same as the doping concentration of the cathode portion  177 . In this case, the resistance portion  179  and the cathode portion  177  may be formed in the same step. That is, the regions to be the resistance portion  179  and the cathode portion  177  may be ion-implanted at the same doping concentration in step S 106 . 
     On the other hand, the doping concentration of the resistance portion  179  may be different from the doping concentration of the cathode portion  177 . In this case, as the polysilicon layer  170 , polysilicon having a doping concentration lower than the doping concentration to be ion-implanted in step S 106  is used. In step S 106 , ions are implanted only into the region to be the cathode portion  177 , and ions are not implanted into the region to be the resistance portion  179 . 
     In step S 108 , the resist mask  190  is removed. In step S 110 , the implanted N type and P type impurities are diffused from the upper surface to the lower surface of the polysilicon layer  170  by heat treatment. In addition, a resist mask  191  is arranged on the polysilicon layer  170 , and etching is performed using the resist mask  191 , whereby the polysilicon layer  170  is patterned. 
     In step S 112 , the resist mask  191  is removed, and the plurality of temperature sensing diode portions  173  having the anode portion  175  and the cathode portion  177  and the resistance portion  179  of the N type are formed. 
     In step  114 , after the interlayer insulating film  38  is formed to cover the resistance portion  179 , the anode portion  175 , and the cathode portion  177 , the contact holes  54 ,  55 , and  56  are formed by patterning the interlayer insulating film  38 . Next, the anode wiring  180 , the cathode wiring  182 , and the connection portion  181  are formed by patterning a metal layer of aluminum, an alloy containing aluminum, or the like arranged on the interlayer insulating film  38 . 
       FIG.  12    illustrates another example of the manufacturing method of the semiconductor device  100 . Herein, similarly to  FIGS.  11 A and  11 B , a step of forming the temperature sensing unit  178  in  FIG.  3 A  will be described. Note that since steps S 100  and S 102  are common to those in  FIG.  11 A , the description thereof is omitted, and subsequent step S 105  will be described. 
     In step S 105 , the resist mask  190  is arranged on the polysilicon layer  170 , and an N type impurity such as arsenic (As), phosphorus (P), or the like is selectively ion-implanted from above the front surface  21  of the semiconductor substrate  10 . A region where the resist mask  190  is arranged corresponds to the P type region that finally becomes the anode portion  175 . A region into which the N type impurity is ion-implanted corresponds to the N type region that finally becomes the cathode portion  177  or the resistance portion  179 . 
     Next, in step S 107 , the resist mask  190  is removed, the resist mask  192  is arranged on the polysilicon layer  170 , and a P type impurity such as boron (B) is ion-implanted from above the front surface  21  of the semiconductor substrate  10 . The resist mask  192  is arranged in the region into which the N type impurities have been ion-implanted in step S 105 , that is, a region where the resist mask  190  has not been arranged. 
     In steps S 105  and S 107 , the N type and P type impurities are ion-implanted with a dimension (width) such that the resistance of the N type region is larger than the resistance of the P type region. Step S 108  and subsequent steps to be performed next are common to those in  FIG.  11   , and thus the description thereof is omitted. 
     While the embodiments of the present invention have been described, the technical scope of the invention is not limited to the above described embodiments. It is apparent to persons skilled in the art that various alterations and improvements can be added to the above-described embodiments. It is also apparent from the scope of the claims that the embodiments added with such alterations or improvements can be included in the technical scope of the invention. 
     The operations, procedures, steps, and stages of each process performed by an apparatus, system, program, and method shown in the claims, embodiments, or diagrams can be performed in any order as long as the order is not indicated by “prior to,” “before,” or the like and as long as the output from a previous process is not used in a later process. Even if the process flow is described using phrases such as “first” or “next” in the claims, embodiments, or diagrams, it does not necessarily mean that the process must be performed in this order. 
     EXPLANATION OF REFERENCES 
     
         
           10 : semiconductor substrate;  12 : source region;  13 : emitter region;  14 : base region;  15 : base region;  16 : accumulation region;  18 : drift region;  20 : buffer region;  21 : front surface;  22 : drain region;  23 : back surface;  24 : drain electrode;  25 : collector region;  26 : collector electrode;  30 : dummy trench portion;  32 : dummy insulating film;  34 : dummy conductive portion;  36 : first insulating film;  37 : second insulating film;  38 : interlayer insulating film;  40 : gate trench portion;  42 : gate insulating film;  44 : gate conductive portion;  50 : gate pad;  52 : source electrode;  53 : emitter electrode;  54 : contact hole;  55 : contact hole;  56 : contact hole;  60 : mesa portion;  70 : transistor portion;  80 : diode portion;  82 : cathode region;  100 : semiconductor device;  102 : end side;  110 : current sensing unit;  120 : active portion;  130 : well region;  170 : polysilicon layer;  172 : current sensing pad;  173 : temperature sensing diode portion;  174 : anode pad;  175 : anode portion;  176 : cathode pad;  177 : cathode portion;  178 : temperature sensing unit;  179 : resistance portion;  180 : anode wiring;  181 : connection portion;  182 : cathode wiring;  183 : connection portion;  185 : conductive layer;  190 : resist mask;  191 : resist mask;  192 : resist mask;  200 : semiconductor device