Semiconductor device

Abstract

To provide a technology that can suppress an increase in the area of a semiconductor chip in a semiconductor device with a built-in temperature sensing diode.SOLUTION: A semiconductor device includes a semiconductor chip. The semiconductor chip includes a transistor having a gate electrode, an input electrode, and an output electrode, a temperature sensing diode, a gate pad, and a sense pad. The temperature sensing diode is connected between the gate electrode and the sense pad of the transistor. The gate pad is electrically connected to the gate electrode of the transistor.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to a semiconductor device. [Background technology]

[0002] Patent Document 1 discloses a semiconductor device in which a temperature sensing diode is built into a semiconductor chip. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-111685 Summary of the Invention [Problem to be solved by the invention]

[0004] A semiconductor chip with a built-in temperature sensing diode is provided with an anode pad electrically connected to the anode of the temperature sensing diode and a cathode pad electrically connected to the cathode of the temperature sensing diode in order to measure the forward voltage of the temperature sensing diode. The provision of such pads increases the area of ​​the semiconductor chip, which increases the manufacturing cost of the semiconductor chip. This specification provides a technology that can suppress the increase in area of ​​the semiconductor chip in a semiconductor device with a built-in temperature sensing diode. [Means for solving the problem]

[0005] The semiconductor device disclosed herein may include a semiconductor chip. The semiconductor chip may include a transistor having a gate electrode, an input electrode, and an output electrode, a temperature sensing diode, a gate pad, and a sense pad. The temperature sensing diode may be connected between the gate electrode and the sense pad of the transistor. The gate pad may be electrically connected to the gate electrode of the transistor.

[0006] The semiconductor device is configured so that the forward voltage of the temperature sensing diode can be measured by connecting a voltage measurement circuit between the gate pad and the sense pad. In the semiconductor device, the gate pad for inputting the gate voltage can also function as one of a pair of pads required for measuring the forward voltage of the temperature sensing diode. This makes it possible to suppress an increase in the area of ​​the semiconductor substrate. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a diagram illustrating a configuration of a semiconductor device according to a first embodiment. [Figure 2] FIG. 2 is a diagram showing a planar layout of a main part of the semiconductor chip according to the first embodiment. [Figure 3] 3 is a cross-sectional view of a main part of the semiconductor chip of the first embodiment, and is a diagram schematically showing a cross-sectional view corresponding to line III-III in FIG. 2. FIG. [Figure 4] 3 is a timing diagram showing the gate voltage, the sense pad voltage, and the measurement voltage in the semiconductor device of the first embodiment. FIG. [Figure 5] FIG. 10 is a diagram showing a planar layout of a main part of a semiconductor chip according to a modified example of the first embodiment. [Figure 6] 6 is a cross-sectional view of a main part of a semiconductor chip according to a modified example of the first embodiment, and is a diagram schematically showing a cross-sectional view corresponding to line VI-VI in FIG. 5. [Figure 7] 6 is a cross-sectional view of a main part of a modified example of the semiconductor chip according to the first embodiment, and is a diagram schematically showing a cross-sectional view corresponding to line VI-VI in FIG. 5. FIG. [Figure 8] FIG. 10 is a diagram illustrating a configuration of a semiconductor device according to a second embodiment. [Figure 9] FIG. 10 is a diagram showing a planar layout of a main part of a semiconductor chip according to a second embodiment. [Figure 10] 10 is a cross-sectional view of a main part of a semiconductor chip according to a second embodiment, and is a diagram schematically showing a cross-sectional view corresponding to the line XX in FIG. 9. [Figure 11]10 is a cross-sectional view of a main part of a semiconductor chip according to a second embodiment, and is a diagram schematically showing a cross-sectional view corresponding to line XI-XI in FIG. 9. [Figure 12] FIG. 10 is a timing diagram of the gate voltage, the sense pad voltage, and the measurement voltage in the semiconductor device of the second embodiment. [Figure 13] FIG. 10 is a diagram illustrating a configuration of a modified example of the semiconductor device of the second embodiment. [Figure 14] 10 is a cross-sectional view of a main part of a semiconductor chip according to a modified example of the second embodiment, and is a diagram schematically showing a cross-sectional view corresponding to the line XI-XI in FIG. 9. DETAILED DESCRIPTION OF THE INVENTION

[0008] (First embodiment) As shown in FIG. 1, the semiconductor device 1 of the first embodiment includes a semiconductor chip 5, a gate drive circuit 6, a voltage measurement circuit 7, and a current source 8.

[0009] The semiconductor chip 5 has a transistor 10 having a gate electrode 12, an input electrode 14, and an output electrode 16. The transistor 10 is not particularly limited, but may be, for example, a transistor having an insulated gate. In this example, the transistor 10 is an IGBT (Insulated Gate Bipolar Transistor). Alternatively, the transistor 10 may be a MOSFET (Metal Oxide Semiconductor Field Effect Transistor).

[0010] The semiconductor chip 5 further includes a gate pad GP, a sense pad SP, an output pad OP, and a temperature sensing diode 20. The gate pad GP is electrically connected to the gate electrode 12 of the transistor 10. The output pad OP is electrically connected to the output electrode 16 of the transistor 10. The gate drive circuit 6 is connected between the gate pad GP and the output pad OP, and is configured to output a gate voltage VG to the gate pad GP for controlling the transistor 10. The current source 8 is electrically connected to the sense pad SP. The current source 8 is configured to output a measurement current Im to the sense pad SP. The measurement current Im may be a constant current.

[0011] The temperature sensing diode 20 is connected between the gate electrode 12 of the transistor 10 and the sense pad SP. The anode of the temperature sensing diode 20 is electrically connected to the sense pad SP, and the cathode of the temperature sensing diode 20 is electrically connected to the gate electrode 12 of the transistor 10. In this way, the temperature sensing diode 20 is connected in the forward direction from the sense pad SP toward the gate electrode 12 of the transistor 10. The voltage measurement circuit 7 is connected between the gate pad GP and the sense pad SP, and is configured to measure the voltage between the gate pad GP and the sense pad SP.

[0012] FIG. 2 shows a planar layout diagram of a main part of the semiconductor chip 5. The semiconductor chip 5 includes a semiconductor substrate 11. The material of the semiconductor substrate 11 is not particularly limited, but may be, for example, silicon (Si). The semiconductor substrate 11 is partitioned into an active region 11A and a peripheral region 11B. The active region 11A is a region of the semiconductor substrate 11 through which a main current flows between the input electrode 14 and the output electrode 16, and is a region in which the gate electrode 12 of the transistor 10 is provided. The peripheral region 11B is a region of the semiconductor substrate 11 partitioned around the active region 11A, and is a region in which a peripheral breakdown voltage structure (e.g., a guard ring, etc.) is provided. A gate pad GP and a sense pad SP are provided on the semiconductor substrate 11 corresponding to the peripheral region 11B.

[0013] As shown in FIG. 3, a gate electrode 12 of a transistor 10 is filled in a trench TR formed in an upper layer of a semiconductor substrate 11. The gate electrode 12 is made of n-type polysilicon. The gate electrode 12 is insulated from the semiconductor substrate 11 by a gate insulating film 13 that covers the inner wall of the trench TR. The gate electrode 12 and the gate insulating film 13 form a trench-type insulating gate. As shown in FIG. 2, a plurality of trench-type insulating gates are provided in an active region 11A of the semiconductor substrate 11. When the semiconductor substrate 11 is viewed in a plane, each of the plurality of trench-type insulating gates extends along one direction and is spaced apart from one another in a direction perpendicular to that direction. In this way, the plurality of trench-type insulating gates are arranged in a striped layout when the semiconductor substrate 11 is viewed in a plane.

[0014] As shown in FIG. 2, in this example, each of the multiple trench-type insulated gates is configured to be separated by a connection region 11C in the active region 11A. A gate wiring GL extending from the gate pad GP and a sense wiring SL extending from the sense pad SP are disposed in the connection region 11C. The gate wiring GL and the sense wiring SL are not particularly limited, but may be wirings made of aluminum, for example. As shown in FIG. 3, the gate wiring GL and the sense wiring SL are patterned on the surface of an interlayer insulating film 15 disposed on the semiconductor substrate 11. A gate runner 17 extending from the gate electrode 12 is formed on the semiconductor substrate 11 in the connection region 11C of the semiconductor substrate 11. The gate runner 17 is made of n-type polysilicon and is a vapor-deposited film formed in the same process as the gate electrode 12. In this way, the gate runner 17 is integrally formed with the gate electrode 12 and is a part of the gate electrode 12.

[0015] A gate wiring through electrode 18 is filled in a contact hole that penetrates the interlayer insulating film 15. The gate wiring through electrode 18 is in contact with a gate wiring GL patterned on the interlayer insulating film 15 and is a part of the gate wiring GL. The material of the gate wiring through electrode 18 is not particularly limited, but may be, for example, tungsten (W), copper (Cu), titanium (Ti), titanium nitride (TiN), or the like. The gate wiring through electrode 18 is in contact with the gate runner 17 and electrically connects the gate wiring GL and the gate runner 17.

[0016] A contact hole penetrating the interlayer insulating film 15 is filled with a p-type region 22. The p-type region 22 is made of p-type polysilicon. The p-type region 22 is in contact with a sense wiring SL patterned on the interlayer insulating film 15, and is also in contact with the gate runner 17. A temperature sensing diode 20 is formed by the pn junction between the p-type region 22 and the n-type gate runner 17.

[0017] Next, temperature measurement using the semiconductor device 1 will be described with reference to FIG. 4. VG is the voltage of the gate pad GP, i.e., the gate voltage. VS is the voltage of the sense pad SP, i.e., the sense pad voltage. Vm is the measured voltage between the gate pad GP and the sense pad SP, and is approximately equal to the forward voltage (VD) of the temperature sense diode 20 (Vm≒VD). In this example, the relationship VS=VG+Vm holds.

[0018] The measurement current Im output from the current source 8 to the sense pad SP flows into the gate drive circuit 6 via the sense pad SP, the temperature sense diode 20, and the gate pad GP. The forward voltage VD of the temperature sense diode 20 varies depending on the temperature. Therefore, the measurement voltage Vm measured by the voltage measurement circuit 7 also varies depending on the temperature. As shown in FIG. 4, in this example, the measurement current Im flows through the temperature sense diode 20 at both the high (Hi) and low (Lo) timings of the gate voltage VG, allowing the measurement voltage Vm to be measured. Note that, because the internal impedance of the gate drive circuit 6 is sufficiently low, the influence of the flow of the measurement current Im on the fluctuations in the gate voltage VG can be ignored.

[0019] In the semiconductor device 1, the gate pad GP for inputting the gate voltage VG can also function as one of a pair of pads required for measuring the forward voltage VD of the temperature sensing diode 20. This makes it possible to suppress an increase in the area of ​​the semiconductor substrate 11.

[0020] Furthermore, in the semiconductor device 1, a part of the gate runner 17 is used as the cathode that constitutes the temperature sensing diode 20. Therefore, a process for forming the cathode of the temperature sensing diode 20 is not required.

[0021] (Modification of the first embodiment) 5 and 6 show modified examples of the semiconductor device 1 of the first embodiment. Note that components common to the semiconductor device 1 of the first embodiment are given the same reference numerals, and descriptions thereof will be omitted.

[0022] As shown in FIG. 5, the modified semiconductor device 1 is characterized in that each of the multiple trench-type insulated gates extends continuously without being separated by a connection region 11C. As shown in FIG. 6, a gate wiring through electrode 18 contacts the gate electrode 12 filled in the trench TR, and a p-type region 22 contacts the gate electrode 12 filled in the trench TR. A temperature sense diode 20 is formed by a pn junction between the p-type region 22 and the n-type gate electrode 12. As shown in FIG. 7, a p-type region 22 may be formed in the trench TR. In this case, a sense wiring through electrode 19 filled in a contact hole penetrating the interlayer insulating film 15 electrically connects the sense wiring SL to the p-type region 22. The sense wiring through electrode 19 is part of the sense wiring SL and may be formed in the same process as the gate wiring through electrode 18. Temperature measurement in the modified semiconductor device 1 is similar to that in the semiconductor device 1.

[0023] In the modified example of the semiconductor device 1, the pn junction that constitutes the temperature sensing diode 20 is embedded in the upper layer of the trench TR, i.e., substantially within the insulated gate. This allows the temperature sensing diode 20 to be disposed near the heat generating location in the semiconductor substrate 11, thereby improving the sensitivity and response speed of temperature measurement.

[0024] (Second embodiment) 8 to 11 show a semiconductor device 2 according to the second embodiment. Note that components that are substantially the same as those in the semiconductor device 1 according to the first embodiment are given the same reference numerals, and descriptions thereof will be omitted.

[0025] 8, in the semiconductor device 2, the anode of the temperature sensing diode 20 is electrically connected to the gate electrode 12 of the transistor 10, and the cathode of the temperature sensing diode 20 is electrically connected to the sense pad SP. In this way, the temperature sensing diode 20 is connected in a forward direction from the gate electrode 12 of the transistor 10 toward the sense pad SP. In addition, the current source 8 is configured to draw the measurement current Im from the sense pad SP.

[0026] As shown in FIGS. 9 to 11 , in the semiconductor device 2, a p-type region 22 is formed adjacent to the gate runner 17. The p-type region 22 is formed by ion-implanting p-type impurities into an n-type region formed in the same process as the gate runner 17. In the semiconductor device 2, an n-type region 24 is further formed adjacent to the p-type region 22. The n-type region 24 is separated from the gate runner 17 by the p-type region 22. The n-type region 24 is formed in the same process as the gate runner 17. A gate wiring through electrode 18 is in contact with both the gate runner 17 and the p-type region 22. A sense wiring through electrode 19 is in contact with the n-type region 24. A temperature sense diode 20 is formed by the pn junction between the p-type region 22 and the n-type region 24.

[0027] 12, in this example, the relationship VS=VG-Vm holds. A measurement current Im flows from the gate drive circuit 6 to the sense pad SP via the gate pad GP and the temperature sense diode 20 and is absorbed by the current source 8. In this example, the measurement current Im flows through the temperature sense diode 20 at both the high (Hi) and low (Lo) timings of the gate voltage VG, allowing the measurement voltage Vm to be measured. Note that, because the internal impedance of the gate drive circuit 6 is sufficiently low, the effect of fluctuations in the gate voltage VG caused by the outflow of the measurement current Im can be ignored.

[0028] (Modification of the second embodiment) 13 shows a modified example of the semiconductor device 2 of the second embodiment. This modified example of the semiconductor device 2 is characterized in that it does not include the current source 8. In addition, this modified example of the semiconductor device 2 is characterized in that it includes a resistor section 30. The resistor section 30 is connected between the cathode of the temperature sensing diode 20 and the output electrode 16 of the transistor 10.

[0029] 14 , in the modified example of the semiconductor device 2, the n-type region 24 extends further from the contact point with the sense wiring penetrating electrode 19 and is electrically connected to the output electrode 16 of the transistor 10. The portion of the n-type region between the sense wiring penetrating electrode 19 and the output electrode 16 of the transistor 10 functions as a resistor portion 30.

[0030] In the modified example of the semiconductor device 2, the measurement current Im flows through the temperature sense diode 20 only when the gate voltage VG is high (Hi), and the measurement voltage Vm can be measured. The modified example of the semiconductor device 2 does not require the provision of the current source 8, and therefore can have a simpler configuration.

[0031] The features of the technology disclosed in this specification are summarized below. Note that the technical elements described below are independent technical elements that exhibit technical usefulness either alone or in various combinations.

[0032] (Feature 1) A semiconductor device including a semiconductor chip, The semiconductor chip comprises: a transistor having a gate electrode, an input electrode, and an output electrode; A temperature sensing diode; A gate pad and a sense pad; and the temperature sensing diode is connected between the gate electrode of the transistor and the sense pad; The gate pad is electrically connected to the gate electrode of the transistor.

[0033] (Feature 2) a voltage measurement circuit, 2. The semiconductor device according to claim 1, wherein the voltage measurement circuit is configured to measure a voltage between the gate pad and the sense pad.

[0034] (Feature 3) a current source connected to the sense pad and configured to source a measurement current into the sense pad; 3. The semiconductor device according to claim 1, wherein an anode of the temperature sensing diode is electrically connected to the sense pad, and a cathode of the temperature sensing diode is electrically connected to the gate electrode of the transistor.

[0035] (Feature 4) the anode of the temperature sensing diode is p-type polysilicon; the cathode of the temperature sensing diode is n-type polysilicon; the gate electrode of the transistor is n-type polysilicon; the anode of the temperature sense diode is in contact with a sense wiring extending from the sense pad; the cathode of the temperature sensing diode is in contact with the gate electrode of the transistor; 4. The semiconductor device according to claim 3, wherein the gate electrode of the transistor is in contact with a gate wiring extending from the gate pad.

[0036] (Feature 5) a current source connected to the sense pad and sinking a measurement current from the sense pad; 3. The semiconductor device according to claim 1, wherein an anode of the temperature sensing diode is electrically connected to the gate electrode of the transistor, and a cathode of the temperature sensing diode is electrically connected to the sense pad.

[0037] (Feature 6) the anode of the temperature sensing diode is p-type polysilicon; the cathode of the temperature sensing diode is n-type polysilicon; the gate electrode of the transistor is n-type polysilicon; the anode of the temperature sensing diode and the gate electrode of the transistor are in contact with a gate wiring extending from the gate pad; 6. The semiconductor device according to feature 5, wherein the cathode of the sense diode is in contact with a sense wiring extending from the sense pad.

[0038] (Feature 7) a resistor connected between the cathode of the temperature sensing diode and the output electrode of the transistor, 3. The semiconductor device according to claim 1, wherein an anode of the temperature sensing diode is electrically connected to the gate electrode of the transistor, and the cathode of the temperature sensing diode is electrically connected to the sense pad.

[0039] (Feature 8) the anode of the temperature sensing diode is p-type polysilicon; the cathode of the temperature sensing diode is n-type polysilicon; the gate electrode of the transistor is n-type polysilicon; the resistor portion is made of n-type polysilicon, the anode of the temperature sensing diode and the gate electrode of the transistor are in contact with a gate wiring extending from the gate pad; 8. The semiconductor device according to claim 7, wherein the cathode of the sense diode and the resistor portion are in contact with a sense wiring extending from the sense pad.

[0040] Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. Furthermore, the technical elements described in this specification or drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technology exemplified in this specification or drawings can achieve multiple objectives simultaneously, and achieving one of these objectives itself has technical utility. [Explanation of symbols]

[0041] 1: semiconductor device, 5: semiconductor chip, 6: gate drive circuit, 7: voltage measurement circuit, 8: current source, 10: transistor, 12: gate electrode, 14: input electrode, 16: output electrode, 20: temperature sensing diode, GP: gate pad, SP: sense pad

Claims

1. A semiconductor device including a semiconductor chip, The semiconductor chip comprises: a transistor having a gate electrode, an input electrode, and an output electrode; A temperature sensing diode; A gate pad and a sense pad; and the temperature sensing diode is connected between the gate electrode of the transistor and the sense pad; The gate pad is electrically connected to the gate electrode of the transistor.

2. a voltage measurement circuit, 2. The semiconductor device according to claim 1, wherein the voltage measurement circuit is configured to measure a voltage between the gate pad and the sense pad.

3. a current source connected to the sense pad and configured to source a measurement current into the sense pad; 3. The semiconductor device according to claim 1, wherein an anode of said temperature sensing diode is electrically connected to said sense pad, and a cathode of said temperature sensing diode is electrically connected to said gate electrode of said transistor.

4. the anode of the temperature sensing diode is p-type polysilicon; the cathode of the temperature sensing diode is n-type polysilicon; the gate electrode of the transistor is n-type polysilicon; the anode of the temperature sense diode is in contact with a sense wiring extending from the sense pad; the cathode of the temperature sensing diode is in contact with the gate electrode of the transistor; 4. The semiconductor device according to claim 3, wherein the gate electrode of the transistor is in contact with a gate wiring extending from the gate pad.

5. a current source connected to the sense pad and sinking a measurement current from the sense pad; 3. The semiconductor device according to claim 1, wherein an anode of said temperature sensing diode is electrically connected to said gate electrode of said transistor, and a cathode of said temperature sensing diode is electrically connected to said sense pad.

6. the anode of the temperature sensing diode is p-type polysilicon; the cathode of the temperature sensing diode is n-type polysilicon; the gate electrode of the transistor is n-type polysilicon; the anode of the temperature sensing diode and the gate electrode of the transistor are in contact with a gate wiring extending from the gate pad; 6. The semiconductor device according to claim 5, wherein said cathode of said sense diode is in contact with a sense wiring extending from said sense pad.

7. a resistor connected between the cathode of the temperature sensing diode and the output electrode of the transistor, 3. The semiconductor device according to claim 1, wherein an anode of said temperature sensing diode is electrically connected to said gate electrode of said transistor, and said cathode of said temperature sensing diode is electrically connected to said sense pad.

8. the anode of the temperature sensing diode is p-type polysilicon; the cathode of the temperature sensing diode is n-type polysilicon; the gate electrode of the transistor is n-type polysilicon; the resistor portion is made of n-type polysilicon, the anode of the temperature sensing diode and the gate electrode of the transistor are in contact with a gate wiring extending from the gate pad; 8. The semiconductor device according to claim 7, wherein said cathode of said sense diode and said resistance portion are in contact with a sense wiring extending from said sense pad.

Images