Semiconductor device

Abstract

An object of the present invention is to provide a structure of a semiconductor device with high reliability. Moreover, the semiconductor device (51) of the present invention has the following features (1) to (3). Feature (1) is: "The lower surface (S13) of the chip bonding material (13) has a shape that conforms to the surface shape of the main current wiring connection area (11) when viewed from above." Feature (2) is: "The emitter sense wiring (10) is directly connected to the side surface of the main current wiring connection area (11)." Feature (3) is: "The IGBT chip (1) has an inactive area (20) where the IGBT does not function in the area below the emitter sense pad (9) and the emitter sense wiring (10)."

Description

Technical Field

[0001] The present invention relates to a semiconductor device including a semiconductor chip having a switching element therein. Background Art

[0002] As a semiconductor device for power, a semiconductor device including a semiconductor chip having a switching element such as an IGBT (Insulated Gate Bipolar Transistor) or a MOSFET (Metal - Oxide - Semiconductor Field - Effect Transistor) therein is generally used.

[0003] As a conventional semiconductor device for power, for example, the semiconductor device disclosed in Patent Document 1 is cited.

[0004] Patent Document 1: Japanese Patent Application Laid - Open No. 2013 - 45996 Summary of the Invention

[0005] Regarding a conventional semiconductor device for power, an IGBT is used as a switching element, and as an emitter potential that is a reference potential for a gate voltage, a potential obtained from an outer peripheral region of an emitter electrode is used, and this gate voltage becomes a control voltage for controlling the operation of the IGBT in the IGBT chip.

[0006] On the other hand, a wiring connection region usually provided at the center of the emitter electrode is electrically connected to an external terminal, and a current flowing through the wiring connection region becomes a main current.

[0007] Ideally, the potential within the emitter electrode surface is constant, but since the emitter electrode has a minute resistance component, if a current flows through the IGBT, a distribution of the potential within the emitter electrode surface occurs.

[0008] Therefore, in a conventional semiconductor device, there is a tendency for the main current to increase along with the potential distribution within the emitter electrode surface. In particular, as the main current, when a large current flows due to a short - circuit or the like, the above - mentioned tendency becomes significant, and thus there is a problem that the IGBT chip may be thermally damaged due to an increase in the main current of the IGBT.

[0009] The present invention is proposed to solve the above - mentioned problems, and an object thereof is to provide a highly reliable semiconductor device.

[0010] The first aspect of the semiconductor device according to the present invention includes: a semiconductor chip having a switching element therein; and a surface electrode provided on the surface of the semiconductor chip, through which a main current flows during the operation of the switching element. The switching element has a control electrode, and the switching element is controlled to operate by applying a control voltage having the potential of the surface electrode as a reference potential to the control electrode. The semiconductor device further includes an insulating film provided on the surface electrode, the insulating film having an opening region, and in the surface electrode, the region within the opening region becomes a wiring connection region. The semiconductor device further includes: a chip bonding material having a lower surface, the lower surface of the chip bonding material being in contact with the surface of the wiring connection region, so that the chip bonding material is electrically connected to the surface electrode; a sense pad provided on the surface of the semiconductor chip without contacting the surface electrode; and a sense wiring provided on the surface of the semiconductor chip, electrically connecting the surface electrode and the sense pad. The potential of the sense pad becomes the control reference potential of the switching element. The lower surface of the chip bonding material has a shape that conforms to the surface shape of the wiring connection region when viewed from above. The sense wiring is connected to the wiring connection region. The semiconductor chip has an inactive region below the sense pad and the sense wiring where the switching element does not function.

[0011] The second aspect of the semiconductor device according to the present invention includes: a semiconductor chip having a switching element therein; and a surface electrode provided on the surface of the semiconductor chip, through which a main current flows during the operation of the switching element. The switching element has a control electrode, and the switching element is controlled to operate by applying a control voltage having the potential of the surface electrode as a reference potential to the control electrode. The semiconductor device includes: a chip wire electrically connected to the surface electrode by contacting at a chip connection point on the surface of the surface electrode; and a sense connection component electrically connected to the surface electrode by contacting at a sense connection point on the surface electrode. The potential of the sense connection point becomes the control reference potential of the switching element. At the surface electrode, the region including the chip connection point is defined as a wiring connection region, and at the surface electrode, the position farthest from the wiring connection region is defined as an electrode remote position. The sense connection point satisfies the connection point arrangement condition of being provided at a position closer to the chip connection point among the chip connection point and the electrode remote position.

[0012] Effects of the Invention

[0013] The first aspect of the semiconductor device of the present invention has the following features (1) to (3).

[0014] (1) The lower surface of the bonding material for the chip has a shape that conforms to the surface shape of the wiring connection area when viewed from above.

[0015] (2) The sensing wiring is connected to the wiring connection area.

[0016] (3) The semiconductor chip has an ineffective area where the switching element does not function in the area below the sensing pad and the sensing wiring.

[0017] The first mode of the semiconductor device of the present invention has the above characteristics (1) to (3). Therefore, the control reference potential during the operation of the switching element is not affected by the resistance component based on the distance from the wiring connection area.

[0018] On the other hand, at the surface electrode of the first mode, the potential of the surface electrode far - away area, which is relatively far from the wiring connection area, i.e., the far - away area reference potential, is affected by the resistance component based on the distance from the wiring connection area, and has a reference potential variation characteristic that varies with respect to the control reference potential.

[0019] Therefore, when a large current flows as the main current of the surface electrode during a short - circuit or the like, the first mode of the semiconductor device of the present invention can reduce the amount of current flowing through the surface electrode far - away area in association with the above - mentioned reference potential variation characteristic.

[0020] As a result, the first mode of the semiconductor device of the present invention can effectively suppress the increase in the amount of the main current by reducing the amount of current flowing through the surface electrode far - away area, and achieve an improvement in the reliability of the device.

[0021] The second mode of the semiconductor device of the present invention has the following characteristic (4).

[0022] (4) The sensing connection point satisfies the connection point configuration condition of being set at a position close to the chip connection point among the chip connection point and the above - mentioned electrode far - away position.

[0023] The second mode of the semiconductor device of the present invention has the above characteristic (4). By arranging the sensing connection point close to the chip connection point, the control reference potential during the operation of the switching element is hardly affected by the resistance component based on the distance from the wiring connection area.

[0024] On the other hand, at the surface electrode of the second mode, the potential of the surface electrode far - away area, which is relatively far from the wiring connection area, i.e., the far - away area reference potential, is affected by the resistance component based on the distance from the wiring connection area, and has a reference potential variation characteristic that varies with respect to the control reference potential.

[0025] Therefore, in the second mode of the semiconductor device of the present invention, when a large current flows during a short circuit or the like and serves as the main current of the surface electrode, the amount of current flowing through the region far from the surface electrode can be reduced in association with the above-described reference potential variation characteristics.

[0026] As a result, in the second mode of the semiconductor device of the present invention, the increase in the amount of main current can be effectively suppressed by reducing the amount of current flowing through the region far from the surface electrode, and the reliability of the device can be improved.

[0027] The object, features, solutions, and advantages of the present invention will become clearer through the following detailed description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is an explanatory diagram showing the structure of the semiconductor device as Embodiment 1.

[0029] Figure 2 It is an explanatory diagram showing the structure of the semiconductor device of Embodiment 1.

[0030] Figure 3 It is a circuit diagram showing the equivalent circuit of the semiconductor device of Embodiment 1.

[0031] Figure 4 It is an explanatory diagram showing the structure of the semiconductor device as Embodiment 2.

[0032] Figure 5 It is an explanatory diagram showing the structure of the semiconductor device as Embodiment 3.

[0033] Figure 6 It is an explanatory diagram showing the structure of the semiconductor device as Embodiment 4.

[0034] Figure 7 It is an explanatory diagram showing the structure of the semiconductor device of Embodiment 4.

[0035] Figure 8 It is a circuit diagram showing the equivalent circuit of the semiconductor device of Embodiment 4.

[0036] Figure 9 It is an explanatory diagram showing the structure of the semiconductor device that is the basic technology.

[0037] Figure 10 It is shown in Figure 9 The circuit diagram of the equivalent circuit of the semiconductor device shown.

[0038] Figure 11 It is a circuit diagram showing the equivalent circuit of the semiconductor device for comparison. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0039] <Basic Technology>

[0040] Figure 9 It is an explanatory diagram showing the structure of a semiconductor device that serves as a basic technology. Figure 9 The upper figure is a cross-sectional view, and the lower figure is a top view. The G-G section of the lower figure becomes the upper figure. In Figure 9 the upper and lower figures of Figure 9 the insulating film 42 is shown as the topmost layer.

[0041] In Figure 9 the semiconductor device 59 shown uses an IGBT as a switching element, and an IGBT chip 31, which is a semiconductor chip having an IGBT inside, is encapsulated.

[0042] As Figure 9 shown, an emitter electrode 33 is provided on the surface of the IGBT chip 31, and a collector electrode 34 is provided on the back surface. The back electrode, i.e., the collector electrode 34, is electrically connected to the main current wiring 35 via the underlying under-chip bonding material 47.

[0043] An insulating film 42 is provided on the surface of the surface electrode, i.e., the emitter electrode 33. The insulating film 42 has an opening region OP42 extending from the center toward the +X direction. The opening region OP42 is a rectangle whose length in the Y direction is longer than its length in the X direction when viewed from above.

[0044] The insulating film 42 also has an opening region OP43 in the outer peripheral portion on the -X direction side on the surface of the IGBT chip 31. The opening region OP43 is a rectangle whose length in the Y direction is slightly longer than its length in the X direction when viewed from above, and has an area smaller than that of the opening region OP42.

[0045] At the emitter electrode 33, the region within the opening region OP42 becomes the main current wiring connection region 41, and the region within the opening region OP43 becomes the emitter sensing region.

[0046] An on-chip bonding material 43 is provided on a part of the central region of the main current wiring connection region 41. That is, by bringing the lower surface S43 of the on-chip bonding material 43 into contact with a part of the surface region of the main current wiring connection region 41, the emitter electrode 3 is electrically connected to the on-chip bonding material 43. In addition, the formation area of the lower surface S43 of the on-chip bonding material 43 is smaller than the surface area of the main current wiring connection region 41.

[0047] A main current wiring 36 is provided on the on-chip bonding material 43, and the main current wiring 36 is electrically connected to the on-chip bonding material 43.

[0048] As Figure 9As shown in the figure above, the emitter sensing region of the emitter electrode 33 existing within the opening region OP43 is electrically connected to the control terminal 32 via the control wire 37.

[0049] The gate pad 38 is electrically connected to the control electrode of the IGBT (not shown), i.e., the gate electrode. It is independently disposed on the surface of the IGBT chip 31 without contacting the emitter electrode 33, and the surface of the gate pad 38 is exposed.

[0050] The gate pad 38 is electrically connected to a gate control terminal (not shown) via a gate control wire (not shown).

[0051] In this way, there exist a control terminal 32 for the emitter electrode 33 and a gate control terminal as the control terminals of the IGBT.

[0052] Al or the like is used as the constituent material of the control wire 37 and the gate control wire. In order to achieve the electrical connection between the control wire 37 and the collector electrode 34, an emitter sensing pad (not shown) is usually provided above the emitter sensing region within the opening region OP43. That is, by joining the control wire 37 to the surface of the emitter sensing pad, the electrical connection between the emitter sensing region of the emitter electrode 33 and the control terminal 32 can be achieved via the emitter sensing pad and the control wire 37. The gate control wire is joined to the surface of the gate pad 38 in the same manner as the control wire 37.

[0053] The main current wiring 36 is electrically connected to the main current wiring 35 via the on-chip bonding material 43, the emitter electrode 33, the IGBT within the IGBT chip 31, the collector electrode 34, and the under-chip bonding material 47.

[0054] Therefore, when the IGBT operates, the main current flows from the main current wiring 35 towards the main current wiring 36 in the semiconductor device 59. The main current wirings 35 and 36 are external wirings for leading out the main current flowing through the IGBT. Figure 9 The current path IP9 shown indicates the current flow of the main current.

[0055] In this way, considering the connectivity with the module, the gate pad 38 and the emitter sensing pad are usually provided at the outer peripheral portion of the IGBT chip 31. That is, the emitter sensing pad is provided above the outer peripheral region of the emitter electrode 33.

[0056] Figure 10 It is Figure 9 a circuit diagram showing the equivalent circuit of the semiconductor device 59 shown in Figure 10 The resistance component of the emitter electrode 33 is considered in Figure 10 In addition, in Figure 10In the figure, the gate pad 38 is represented by "G", and the emitter sense pad 39 is represented by "Es".

[0057] Actually, the resistance component of the emitter electrode 33 is distributed throughout the entire emitter electrode 33 except for the region where it is bonded to the chip bonding material 43. However, for simplicity, in Figure 10 it is considered as the emitter electrode resistance component R9 with a lumped constant. That is, the IGBTs in the IGBT chip 31 are classified into two. The IGBT through which the collector current Ic2 flows in the main current wiring connection region 41 and its vicinity is set as IGBT 62, and the IGBT through which the collector current Ic1 flows in the outer peripheral region of the emitter electrode 3 separated from the main current wiring connection region 11 is set as IGBT 61. In addition, an emitter sense pad 39 is provided in the outer peripheral region of the emitter electrode 3.

[0058] Therefore, as Figure 10 shown, the collectors of IGBT 61 and 62 are commonly connected by the under-chip bonding material 47, and the gates of IGBT 61 and 62 are commonly connected to the gate pad 38.

[0059] On the other hand, the emitter of IGBT 62 is connected to the chip bonding material 43, and the emitter of IGBT 61 is connected to the emitter sense pad 39. There is an emitter electrode resistance component R9 between the emitters of IGBT 61 and 62.

[0060] This emitter electrode resistance component R9 becomes a resistance component based on the distance from the lower surface of the chip bonding material 43 to the emitter sense pad 39 at the emitter electrode 33.

[0061] Regarding the semiconductor device 59 with such a structure, a gate voltage VGE1 is applied between the gate pad 38 and the emitter sense pad 39 to make the IGBTs in the IGBT chip 31 in an operating state.

[0062] If the IGBTs are turned on, the collector current Ic1 flows through IGBT 61, and the collector current Ic2 flows through IGBT 62.

[0063] Since there is an emitter electrode resistance component R9 between the emitters of IGBT 61 and 62, due to the voltage drop caused by the emitter electrode resistance component R9, the emitter potential of IGBT 62 is lower than the emitter potential of IGBT 61.

[0064] As a result, as shown in the following formula (1), the gate voltage VGE2 of IGBT 62 is higher than the gate voltage VGE1.

[0065] VGE2 = VGE1 + R9·Ic1…(1)

[0066] In Equation (1), the resistance value of the emitter electrode resistance component R9 is directly represented by "R9", and the current value of the collector current Ic2 is directly represented by "Ic2".

[0067] Thus, the collector current Ic2 of the semiconductor device 59 tends to increase along with the in-plane potential distribution of the emitter electrode 33. In particular, when a large current flows through the IGBT due to a short circuit or the like, this tendency becomes significant, and thus the IGBT chip 31 may be thermally damaged due to the increase in the collector current Ic2.

[0068] Thus, the semiconductor device 59, which is a basic technology, has a problem of low reliability.

[0069] On the other hand, the semiconductor device disclosed in Patent Document 1 focuses on the resistance component of the source electrode corresponding to the emitter electrode 33, changes the potential of the pad for source sensing with respect to the conventional structure, and reduces the output fluctuation of the current detection element built in the switching element. However, it is insufficient for improving the reliability of the semiconductor device disclosed in Patent Document 1.

[0070] The embodiments described below solve the problems of the basic technology represented by the semiconductor device 59.

[0071] <Embodiment 1>

[0072] Figure 1 And Figure 2 are explanatory diagrams showing the structure of the semiconductor device 51 according to Embodiment 1 of the present invention. Figure 1 The upper diagram is a cross-sectional view, and the lower diagram is a plan view, Figure 2 is a plan view. Figure 1 The A-A cross-section of the lower diagram of Figure 1 becomes the upper diagram of Figure 2 The B-B cross-section of Figure 1 also becomes the upper diagram of Figure 1 In the upper and lower diagrams of Figure 2 and

[0073] Figure 1 The lower diagram of Figure 2 is a plan view with the uppermost part being the insulating film 12,

[0074] In Figure 1 And Figure 2 The semiconductor device 51 shown in uses an IGBT as a switching element, and packages an IGBT chip, which is a semiconductor chip having an IGBT, inside.

[0075] As Figure 1 and Figure 2 shown, an emitter electrode 3 is provided on the surface of the IGBT chip 1. The emitter electrode 3 is formed in most of the area on the surface of the IGBT chip 1 except for the formation areas of the gate pad 8, the emitter sense pad 9, and the emitter sense wiring 10.

[0076] A collector electrode 4 is provided on the back surface of the IGBT chip 1. The back electrode, i.e., the collector electrode 4, is electrically connected to the main current wiring 5 via the under-chip bonding material 17 provided below. At the main current wiring 5, the under-chip bonding material 17 is below and forms the base.

[0077] An insulating film 12 is provided on the surface of the emitter electrode 3. The insulating film 12 has an opening region OP12 from the center toward the +X direction. The opening region OP12 is a rectangle having a length in the Y direction longer than the length in the X direction when viewed from above.

[0078] The insulating film 12 functions as a protective film and is formed, for example, by coating polyimide on the surface of the emitter electrode 3.

[0079] At the emitter electrode 3, the region within the opening region OP12 becomes the main current wiring connection region 11.

[0080] An on-chip bonding material 13 is provided over the entire area of the main current wiring connection region 11. The lower surface S13 of the on-chip bonding material 13 has a shape that conforms to the surface shape of the main current wiring connection region 11 when viewed from above. The on-chip bonding material 13 corresponds to the "bonding material for chip".

[0081] The lower surface S13 of the on-chip bonding material 13 contacts the surface of the main current wiring connection region 11, so that the on-chip bonding material 13 is electrically connected to the emitter electrode 3. Therefore, the on-chip bonding material 13 is provided over the entire area of the surface of the main current wiring connection region 11.

[0082] A main current wiring 6 is provided on the on-chip bonding material 13, and the main current wiring 6 is electrically connected to the on-chip bonding material 13.

[0083] As Figure 2 shown, the gate pad 8 is provided on the surface of the IGBT chip 1 so as not to contact the emitter electrode 3, and the emitter sense pad 9 is provided on the surface of the IGBT chip 1 so as not to contact the gate pad 8 and the emitter electrode 3. The gate pad 8 and the emitter sense pad 9 are provided in the end region on the -X direction side of the IGBT chip 1.

[0084] The gate pad 8 and the emitter sense pad 9 are each rectangular in a plan view, with a length in the Y direction slightly longer than the length in the X direction.

[0085] The gate pad 8 is electrically connected to the gate electrode of the IGBT via gate wiring (not shown) and is electrically connected to an external gate control terminal (not shown) via a gate control wire (not shown). The gate electrode of the IGBT corresponds to "the control electrode of the switching element".

[0086] The emitter sense wiring 10 is provided on the surface of the IGBT chip 1 and functions as a sense wiring for electrically connecting the emitter electrode 3 and the emitter sense pad 9. Specifically, the emitter sense wiring 10 is provided to extend in the +X direction from the emitter sense pad 9 and, as Figure 2 shown, contacts the emitter electrode 3 at the sense connection point 25 on the side that becomes the main current wiring connection area 11.

[0087] At the emitter electrode 3, a cutout area extending in the X direction is provided so as not to contact the emitter sense wiring 10 except at the sense connection point 25.

[0088] As Figure 1 shown in the upper figure, the emitter sense pad 9 is electrically connected to the control terminal 2 via the control wire 7. Specifically, by joining one end of the control wire 7 to the surface of the emitter sense pad 9, electrical connection between the emitter sense pad 9 and the control terminal 2 can be achieved.

[0089] The gate control wire is joined to the surface of the gate pad 8 in the same manner as the control wire 7. In addition, Al or the like is used as the constituent material of the control wire 7 and the gate control wire.

[0090] Thus, as the control terminals of the switching element, i.e., the IGBT, within the IGBT chip 1, there are the control terminal 2 for the emitter electrode 3 and the gate control terminal.

[0091] The main current wiring 6 is electrically connected to the main current wiring 5 via the die attach material 13, the emitter electrode 3, the IGBT within the IGBT chip 1, the collector electrode 4, and the underfill 17.

[0092] Therefore, when the IGBT within the IGBT chip 1 operates in the semiconductor device 51 of Embodiment 1, the main current flows as the collector current from the main current wiring 5 toward the main current wiring 6. The main current wirings 5 and 6 are external wirings for leading out the main current flowing through the IGBT. Figure 1 and Figure 2 The current path IP1 shown in

[0093] In the case of the semiconductor device 51, the emitter electrode 3, the emitter sense pad 9, and the emitter sense wiring 10 are integrally formed on the surface of the IGBT chip 1.

[0094] On the other hand, as Figure 1 and Figure 2 shown, in the IGBT chip 1, the IGBT structural elements are not formed in the ineffective region 20 below the emitter sense pad 9 and the emitter sense wiring 10. This ineffective region 20 becomes a region where the switching element, i.e., the IGBT, does not function. In addition, a field insulating film for element isolation may be formed as the ineffective region 20.

[0095] In addition, the region below the gate pad 8 in the IGBT chip 1 also becomes the ineffective region 20 where the IGBT does not function.

[0096] Figure 3 is a circuit diagram showing the equivalent circuit of the semiconductor device 51 shown in Figure 1 and Figure 2 . In Figure 3 , the resistance component of the emitter electrode 3 is considered. In addition, in Figure 3 , the gate pad 8 is represented by "G", and the emitter sense pad 9 is represented by "Es".

[0097] Actually, the resistance component of the emitter electrode 3 is distributed in the entire emitter electrode 3 except for the main current wiring connection region 11 that is joined to the lower surface S13 of the chip bonding material 13. However, for simplicity, in Figure 3 , it is considered as a lumped constant as the emitter electrode resistance component R1. That is, the IGBTs of the IGBT chip 1 are classified into two. The IGBT that passes the collector current Ic2 in the main current wiring connection region 11 and its vicinity is set as the IGBT 62, and the IGBT that passes the collector current Ic1 in the outer peripheral region of the emitter electrode 3 separated from the main current wiring connection region 11 is set as the IGBT 61. This outer peripheral region becomes a surface electrode remote region.

[0098] Therefore, as Figure 3 shown, the collectors of the IGBTs 61 and 62 are commonly connected by the under-chip bonding material 17, and the control electrodes, i.e., the gates, of the IGBTs 61 and 62 are commonly connected by the shown gate pad 8.

[0099] On the other hand, the emitter of the IGBT 62 and the emitter sense pad 9 are electrically connected in the main current wiring connection region 11. At this time, there is an emitter electrode resistance component R1 between the emitter of the IGBT 61 and the emitter of the IGBT 61.

[0100] The emitter electrode resistance component R1 at the emitter electrode 3 becomes a resistance component based on the distance from the lower surface S13 of the chip bonding material 13, i.e., the main current wiring connection region 11, to the surface electrode remote region of the emitter electrode 3. Therefore, the emitter of the IGBT 61 is connected to the main current wiring connection region 11 via the emitter electrode resistance component R1.

[0101] Regarding the semiconductor device 51 having the equivalent circuit as described above, a gate voltage VGE2 is applied between the gate pad 8 and the emitter sense pad 9 to make the IGBT in the IGBT chip 1 in an operating state. Here, the potential obtained through the emitter sense pad 9 becomes the control reference potential.

[0102] That is, the IGBT has a control electrode, i.e., a gate. By applying a control voltage, i.e., a gate voltage VGE2, having the potential of the emitter electrode 3 as the reference potential, to the gate of the IGBT, the operation of the IGBT is controlled. In this way, for the semiconductor device 51, the gate voltage VGE2 becomes the control voltage for the IGBT.

[0103] If the IGBT in the IGBT chip 1 is turned on, a collector current Ic1 flows through the IGBT 61, and a collector current Ic2 flows through the IGBT 62. The sum of the collector current Ic1 and the collector current Ic2 becomes the main current of the IGBT.

[0104] On the other hand, since the IGBT chip 1 has an inactive region 20 below the emitter sense pad 9 and the emitter sense wiring 10, the emitter potential of the IGBT 62 is not affected by the main current.

[0105] By forming the emitter sense pad 9 and the emitter sense wiring 10 above the inactive region 20, the main current does not flow through the emitter sense wiring 10, but mainly the charge and discharge current of the gate of the IGBT flows through it. The charge and discharge current of the gate is a current amount that is two or three orders of magnitude smaller than the main current. Therefore, the voltage drop caused by the current flowing through the emitter sense wiring 10 becomes a negligible level. As a result, the potential of the emitter sense pad 9, i.e., the control reference potential, is not affected by the main current.

[0106] Since there is an emitter electrode resistance component R1 between the emitters of the IGBTs 61 and 62, a voltage drop caused by the emitter electrode resistance component R1 is generated between the IGBTs 61 and 62. The semiconductor device 51 has a reference potential rising characteristic in which the emitter potential of the IGBT 61 is relatively higher than the emitter potential of the IGBT 62 due to the above voltage drop. This reference potential rising characteristic corresponds to the "reference potential variation characteristic".

[0107] That is, the reference potential in the far - away region of the surface electrode far from the main current wiring connection region 11 is affected by the emitter - electrode resistance component R1 based on the distance from the main current wiring connection region 11, and has a reference - potential rising characteristic higher than the control reference potential.

[0108] As a result, as shown in the following formula (2), the gate voltage VGE1 of the IGBT 61 is lower than the gate voltage VGE2.

[0109] VGE1 = VGE2 - R1·Ic1…(2)

[0110] In formula (2), the resistance value of the emitter - electrode resistance component R1 is directly denoted as “R1”, and the current value of the collector current Ic1 is directly denoted as “Ic1”.

[0111] As shown in formula (2), due to the reference - potential rising characteristic, the emitter potential of the IGBT 61 rises by an amount of (R1·Ic1). Therefore, the gate voltage VGE1 of the IGBT 61 is lower than the gate voltage VGE2. As a result, the collector current Ic1 flowing through the IGBT 61 can be reduced.

[0112] In this way, the IGBT 61 has a reference - potential rising characteristic based on the potential distribution in the plane of the emitter electrode 3. In particular, when a large current flows through the IGBT due to a short - circuit or the like, this reference - potential rising characteristic becomes significant.

[0113] Therefore, if a large current is about to flow through the IGBT due to a short - circuit or the like, the collector current Ic1 flowing through the IGBT 61 is reduced due to the above - mentioned reference - potential rising characteristic. Therefore, an increase in the main current of the IGBT can be effectively suppressed.

[0114] In this way, when a large current such as a short - circuit is applied, the semiconductor device 51 applies negative feedback to the gate voltage VGE1 of the IGBT 61 through the emitter - electrode resistance component R1, thereby effectively suppressing an increase in the main current and improving the reliability of the device.

[0115] That is, for the semiconductor device 51, even if the collector current Ic2 increases due to a large current such as a short - circuit, the total amount of the collector current, that is, (Ic1 + Ic2), is suppressed by controlling the current in such a way that the collector current Ic1 decreases, thereby improving the reliability of the device.

[0116] Further, by designing the size of the opening region OP12 of the insulating film 12, the value of the emitter electrode resistance component R1 can be arbitrarily adjusted. For example, by reducing the size of the opening region OP12, if the surface area of the main current wiring connection region 11 becomes smaller, the emitter electrode resistance component R1 becomes larger, and the above-mentioned reference potential rising characteristic can be improved.

[0117] However, although the emitter electrode resistance component R1 is minute, power loss is still generated. Therefore, when applied to an actual semiconductor device, it is necessary to appropriately design the size of the opening region OP12 in consideration of the trade-off relationship between the degree of decrease in the amount of the collector current Ic1 and the increase in power loss.

[0118] On the other hand, when the emitter electrode 3 is electrically connected to the on-chip bonding material 13 only in a partial region of the surface of the main current wiring connection region 11, the magnitude of the emitter electrode resistance component R1 changes according to the area in contact with the on-chip bonding material 13 in the surface area of the main current wiring connection region 11, making it difficult to perform an optimal design.

[0119] Therefore, in the semiconductor device 51 of the first embodiment, the surface shape of the lower surface S13 of the on-chip bonding material 13 conforms to the surface shape of the main current wiring connection region 11, and the entire region of the surface of the main current wiring connection region 11 is bonded to the lower surface S13 of the on-chip bonding material 13.

[0120] That is, the semiconductor device 51 realizes a surface-to-surface bonding structure by bringing the entire region of the surface of the main current wiring connection region 11 existing in the opening region OP12 of the insulating film 12 into contact with the lower surface S13 of the on-chip bonding material 13, and this surface-to-surface bonding structure realizes the electrical connection between the emitter electrode 3 and the on-chip bonding material 13.

[0121] Therefore, the semiconductor device 51 of the first embodiment can accurately set the emitter electrode resistance component R1 by the size of the opening region OP12.

[0122] In order to realize the above-mentioned surface-to-surface bonding structure, it is preferable to reliably and gaplessly arrange the on-chip bonding material 13 in the opening region OP12 of the insulating film 12 during the assembly of the semiconductor device 51. Therefore, in the first embodiment, the surface shape of the lower surface S13 of the on-chip bonding material 13 conforms to the surface of the main current wiring connection region 11.

[0123] For example, in the case where solder is used as the on-chip bonding material 13, by plating the opening region OP12 of the insulating film 12, the on-chip bonding material 13 is filled in the opening region OP12 without gaps, so that the on-chip bonding material 13 having a lower surface S13 that contacts the entire surface of the main current wiring connection region 11 can be obtained.

[0124] Thus, the semiconductor device 51 of Embodiment 1 has the following features (1) to (3).

[0125] (1) The lower surface S13 of the on-chip bonding material 13 has a shape that conforms to the surface shape of the main current wiring connection region 11 in a top view.

[0126] (2) The emitter sensing wiring 10 is directly connected to the side surface of the main current wiring connection region 11.

[0127] (3) The IGBT chip 1 has an ineffective region 20 where the IGBT does not function in a region below the emitter sensing pad 9 and the emitter sensing wiring 10.

[0128] In addition, regarding the above features (1) to (3), the on-chip bonding material 13 corresponds to the "bonding material for chip", the main current wiring connection region 11 corresponds to the "wiring connection region", the emitter sensing wiring 10 corresponds to the "sensing wiring", the IGBT chip 1 corresponds to the "semiconductor chip", the emitter sensing pad 9 corresponds to the "sensing pad", and the IGBT corresponds to the "switching element".

[0129] Since the semiconductor device 51 of Embodiment 1 has the above features (1) to (3), the control reference potential obtained from the emitter sensing pad 9 during IGBT operation is not affected by the emitter electrode resistance component R1 based on the distance from the main current wiring connection region 11.

[0130] Therefore, if the voltage value of the original gate-emitter voltage of the IGBT in the IGBT chip 1 is set as the control voltage value VG0, the gate voltage VGE2 is equal to the control voltage value VG0.

[0131] On the other hand, at the emitter electrode 3 of the semiconductor device 51, the emitter potential of the IGBT 61 is affected by the emitter electrode resistance component R1 based on the distance from the main current wiring connection region 11, and has a reference potential rising characteristic higher than that of the emitter potential of the IGBT 62.

[0132] Therefore, as shown in the above formula (2), the gate voltage VGE1 of the IGBT 61 is lower than the gate voltage VGE2.

[0133] Here, the emitter potential of the IGBT 61 corresponds to the "far - away region reference potential" at the surface - electrode - far - away region that is relatively far from the main - current wiring connection region 11, the emitter potential of the IGBT 62 corresponds to the control reference potential obtained from the emitter sensing pad 9, and the "reference potential rising characteristic" corresponds to the "reference potential variation characteristic".

[0134] Therefore, when the semiconductor device 51 of Embodiment 1 has a large current flowing through it, such as during a short - circuit, and the main current flows through the emitter electrode 3, it can reduce the amount of the collector current Ic1 flowing through the surface - electrode - far - away region in association with the above - mentioned reference potential rising characteristic.

[0135] As a result, the semiconductor device 51 of Embodiment 1 can effectively suppress the increase in the amount of the main current of the IGBT by reducing the collector current Ic1, and achieve an improvement in the reliability of the device.

[0136] In addition, regarding the above - mentioned effect of Embodiment 1, the emitter electrode 3 corresponds to the "surface electrode". Also, when the IGBTs in the IGBT chip 1 are classified into IGBT 61 and IGBT 62, the gate - to - emitter voltage VGE2 corresponds to the "control voltage" for the IGBT 62, and the gate - to - emitter voltage VGE1 corresponds to the "control voltage" for the IGBT 61.

[0137] <Embodiment 2>

[0138] Figure 4 FIG. is an explanatory diagram showing the structure of the semiconductor device 52 according to Embodiment 2 of the present invention. Figure 4 The upper figure above is a cross - sectional view, and the lower figure is a top view. Figure 4 The C - C cross - section of the lower figure becomes Figure 4 the upper figure above, and XYZ orthogonal coordinate systems are respectively marked in Figure 4 both the upper figure and the lower figure above.

[0139] In Figure 4 the semiconductor device 52 shown uses an IGBT as a switching element, and packages an IGBT chip 1B, which is a semiconductor chip having an IGBT inside.

[0140] As Figure 4 shown, an emitter electrode 3 is provided on the surface of the IGBT chip 1B, and a collector electrode 4 is provided on the back surface. The collector electrode 4, which serves as the back electrode, is electrically connected to the main current wiring 5 via the under - chip bonding material 17.

[0141] One end of each of the plurality of main current conductors 14 contacts a corresponding chip connection point 23B among the plurality of chip connection points 23B on the surface of the emitter electrode 3, thereby being electrically connected to the emitter electrode 3. The plurality of chip connection points 23B are discretely arranged in the Y direction near the center in the X direction. In this way, one end of each of the plurality of main current conductors 14 is joined to the surface of the emitter electrode 3. The other ends of the plurality of main current conductors 14 are joined to the main current wiring 6 on the surface. The plurality of main current conductors 14 correspond to the "plurality of chip conductors".

[0142] One end of the control conductor 7B contacts the sensing connection point 25B on the surface of the emitter electrode 3, thereby being electrically connected to the emitter electrode 3. That is, one end of the control conductor 7B is joined to the surface of the emitter electrode 3.

[0143] In addition, as Figure 4 shown in the following figure, the sensing connection point 25B is provided near the 3rd and 4th chip connection points 23B counted from the +Y direction side among the plurality of chip connection points 23B. In addition, the control conductor 7B and the plurality of main current conductors 14 are electrically independent and arranged so as not to contact each other. The other end of the control conductor 7B is joined to the control terminal 2.

[0144] Here, at the emitter electrode 3, the region including the plurality of chip connection points 23B is defined as the main current wiring connection region 11B, and at the emitter electrode 3, the position farthest from the main current wiring connection region 11B is defined as the electrode remote position. At the emitter electrode 3 shown in Figure 4 , the outer peripheral surface on the -X side is the electrode remote position. In addition, the emitter electrode 3 corresponds to the "surface electrode", and the main current wiring connection region 11B corresponds to the "wiring connection region".

[0145] The sensing connection point 25B satisfies the connection point arrangement condition of being provided at a position close to the chip connection point 23B among the chip connection point 23B and the above-mentioned electrode remote position.

[0146] The sensing connection point 25B only needs to satisfy the above connection point arrangement condition in the relationship with at least one of the plurality of main current conductors 14. In addition, the potential obtained from the sensing connection point 25B becomes the control reference potential.

[0147] As Figure 4 shown, the gate pad 8 is arranged on the surface of the IGBT chip 1B so as not to contact the emitter electrode 3. The gate pad 8 is arranged in the end region on the -X direction side of the IGBT chip 1B. The gate pad 8 is rectangular with a length in the Y direction slightly longer than the length in the X direction in a top view. In addition, the region below the gate pad 8 of the IGBT chip 1B becomes an ineffective region where the IGBT does not function.

[0148] The gate pad 8 is electrically connected to the gate electrode of the IGBT via gate wiring (not shown), and is electrically connected to a gate control terminal (not shown) via a gate control wire (not shown).

[0149] The gate control wire is bonded onto the surface of the gate pad 8. In addition, Al or the like is used as the constituent material of the control wire 7B, the main current wire 14, and the gate control wire.

[0150] Thus, like the first embodiment, the second embodiment has a control terminal 2 for the emitter electrode 3 and a gate control terminal as the control terminals of the IGBT, which is a switching element within the IGBT chip 1B.

[0151] The main current wiring 6 is electrically connected to the main current wiring 5 via a plurality of main current wires 14, the emitter electrode 3, the IGBT within the IGBT chip 1B, the collector electrode 4, and the under-chip bonding material 17.

[0152] Therefore, when the IGBT within the IGBT chip 1B of the semiconductor device 52 of the second embodiment operates, the main current flows as a collector current from the main current wiring 5 toward the main current wiring 6. The main current wirings 5 and 6 are external wirings for leading out the main current flowing through the IGBT. Figure 4 The shown current path IP2 shows the current flow of the main current.

[0153] The semiconductor device 52 of the second embodiment is represented by the equivalent circuit shown in Figure 3 as in the first embodiment. However, in Figure 3 the main current wiring connection region 11 shown is replaced with the main current wiring connection region 11B, and the emitter sense pad 9 is replaced with the sense connection point 25B.

[0154] That is, regarding the IGBT within the IGBT chip 1B, the IGBT through which the collector current Ic2 flows in the main current wiring connection region 11B and its vicinity is defined as the IGBT 62, and the IGBT through which the collector current Ic1 flows in the outer peripheral region of the emitter electrode 3 separated from the main current wiring connection region 11B is defined as the IGBT 61. This outer peripheral region becomes the surface electrode remote region.

[0155] In addition, in order to make the equivalent circuit of the semiconductor device 52 the circuit shown in Figure 3 it is preferable to dispose the sense connection point 25B close to any one of the plurality of chip connection points 23B. That is, it is preferable to dispose the sense connection point 25B close to any one of the plurality of chip connection points 23B such that the resistance component between the sense connection point 25B and the main current wiring connection region 11B is negligible.

[0156] Therefore, similar to the semiconductor device 51, when a large current such as a short circuit flows through the semiconductor device 52 of Embodiment 2, negative feedback is applied to the gate voltage VGE1 of the IGBT 61 due to the reference potential rising characteristic of the IGBT 61, thereby effectively suppressing the increase in the main current and improving the reliability of the device.

[0157] Thus, the semiconductor device 52 of Embodiment 2 has the following feature (4).

[0158] (4) The sensing connection point 25B of the control wire 7B satisfies the connection point arrangement condition of being set at the position of the chip connection point 23B near the emitter electrode 3 and at the chip connection point 23B in the position where the electrode is far from the chip connection point 23B.

[0159] In addition, regarding the above feature (4), the control wire 7B corresponds to the "sensing connection component" or "sensing wire", and the emitter electrode 3 corresponds to the "surface electrode".

[0160] The semiconductor device 52 of Embodiment 2 has the above feature (4). Therefore, by arranging the sensing connection point 25B close to one of the plurality of chip connection points 23B, when the IGBT operates, the control reference potential obtained from the sensing connection point 25B is hardly affected by the emitter electrode resistance component R1 based on the distance from the main current wiring connection area 11B.

[0161] Therefore, if the voltage value of the original gate-emitter voltage of the IGBT in the IGBT chip 1B is set as the control voltage value VG0, the gate voltage VGE2 is equal to the control voltage value VG0.

[0162] On the other hand, at the emitter electrode 3 of the semiconductor device 52, the emitter potential of the IGBT 61 is affected by the emitter electrode resistance component R1 based on the distance from the main current wiring connection area 11B, and has a reference potential rising characteristic higher than the emitter potential of the IGBT 62.

[0163] Therefore, as shown in the above formula (2), the gate voltage VGE1 of the IGBT 61 is lower than the gate voltage VGE2.

[0164] Here, the emitter potential of the IGBT 61 corresponds to the "reference potential in the far region" at the surface electrode far region relatively far from the wire connection area.

[0165] Therefore, when a large current flows during a short circuit or the like in the semiconductor device 52 of Embodiment 2 and serves as the main current flowing through the emitter electrode 3, the amount of the collector current Ic1 flowing through the surface electrode remote region can be reduced in association with the above-described reference potential rise characteristic of the IGBT 61.

[0166] As a result, the semiconductor device 52 of Embodiment 2 can effectively suppress an increase in the amount of the main current of the IGBT by reducing the collector current Ic1, and improve the reliability of the device.

[0167] Moreover, the semiconductor device 52 of Embodiment 2 can relatively simply achieve the electrical connection between the sensing connection point 25B of the emitter electrode 3 and the control terminal 2 by controlling the wire 7B.

[0168] In addition, the semiconductor device 52 of Embodiment 2 can lead out a large main current to the outside by achieving the electrical connection with the emitter electrode 3 by the plurality of main current wires 14.

[0169] Furthermore, regarding the above effects of Embodiment 2, the emitter electrode 3 corresponds to the "surface electrode". In addition, when the IGBTs in the IGBT chip 1 are classified into the IGBTs 61 and 62, the gate voltage VGE2 corresponds to the "control voltage" for the IGBT 62, and the gate voltage VGE1 corresponds to the "control voltage" for the IGBT 61. Also, the control wire 7B corresponds to the "sensing bonding member" or the "sensing wire", and the main current wire 14 corresponds to the "chip wire".

[0170] The sensing connection point 25B of the control wire 7B can exhibit the above effects by satisfying the above-described connection point arrangement conditions.

[0171] However, when the semiconductor device 52 of Embodiment 2 exhibits the above effects, the sensing connection point 25B is preferably as close as possible to any one of the plurality of chip connection points 23B. The reason is that the emitter electrode resistance component R1 of the emitter electrode 3 can be increased, and the suppression effect of the amount of the main current can be improved.

[0172] Moreover, the sensing connection point 25B is preferably close to the connection point existing at the center of the emitter electrode 3 among the plurality of chip connection points 23B.

[0173] The reason is that, on the emitter electrode 3, the potential difference between the sensing connection point 25B and each of the chip connection points 23B existing at both ends in the Y direction can be suppressed to the minimum.

[0174] <Embodiment 3>

[0175] Figure 5This is an explanatory diagram showing the structure of Embodiment 3 of the present invention, i.e., the semiconductor device 53. Figure 5 The upper figure is a cross-sectional view, and the lower figure is a top view. Figure 5 The D-D cross-section of the lower figure of Figure 5 becomes Figure 5 the upper figure of Figure 5 . In Figure 5 the upper and lower figures of Figure 5 , the XYZ orthogonal coordinate system is respectively marked.

[0176] In Figure 5 the semiconductor device 53 shown uses an IGBT as a switching element, and an IGBT chip, i.e., an IGBT chip 1C having an IGBT inside is packaged. Hereinafter, the same parts as those of the semiconductor device 52 shown in Figure 4 are marked with the same reference numerals and the description is appropriately omitted, and the description will be centered on the characteristic parts of the semiconductor device 53.

[0177] As Figure 5 shown, the gate pad 8 is disposed on the surface of the IGBT chip 1C so as not to contact the emitter electrode 3, and the emitter sense pad 9 is disposed on the surface of the IGBT chip 1C so as not to contact the gate pad 8 and the emitter electrode 3. The gate pad 8 and the emitter sense pad 9 are disposed in the end region on the -X direction side of the IGBT chip 1C.

[0178] When viewed from above, the gate pad 8 and the emitter sense pad 9 are each rectangular with a length in the Y direction slightly longer than the length in the X direction.

[0179] The gate pad 8 is electrically connected to the gate electrode of the IGBT via a gate wiring (not shown), and is electrically connected to a gate control terminal (not shown) via a gate control wire (not shown).

[0180] The emitter sense wiring 10 is disposed on the surface of the IGBT chip 1C and is a sense wiring that electrically connects the emitter electrode 3 and the emitter sense pad 9. Specifically, the emitter sense wiring 10 is disposed to extend along the +X direction from the emitter sense pad 9, and directly contacts the emitter electrode 3 at a sense connection point 25C on the side that becomes the main current wiring connection region 11.

[0181] The emitter electrode 3 is provided with a cutout region extending in the X direction so as not to contact the emitter sense wiring 10 except at the sense connection point 25C.

[0182] The sense connection point 25C satisfies the connection point arrangement condition of being disposed at the position of the chip connection point 23B closer to the emitter electrode 3 among the chip connection point 23B and the electrode remote position.

[0183] The connection point 25C for sensing only needs to satisfy the above connection point configuration conditions in relation to at least one of the plurality of main current conductors 14.

[0184] As Figure 5 As shown in the following figure, the connection point 25C for sensing is provided near the fifth connection point 23B for chips counted from the +Y direction side among the plurality of connection points 23B for chips, satisfying the above connection point configuration conditions.

[0185] As Figure 5 As shown in the above figure, the emitter sensing pad 9 is electrically connected to the control terminal 2 via the control wire 7. Specifically, by joining the front end of the control wire 7 to the surface of the emitter sensing pad 9, the electrical connection between the emitter sensing pad 9 and the control terminal 2 can be achieved.

[0186] In addition, materials such as Al are used as the constituent materials of the control wire 7, the main current conductor 14, and the control wire for the gate.

[0187] Moreover, in the IGBT chip 1C, structural elements of the IGBT are not formed in the ineffective region 20C below the emitter sensing pad 9 and the emitter sensing wiring 10. This ineffective region 20C becomes a region where the switching element, i.e., the IGBT, does not function.

[0188] Also, in the IGBT chip 1C, the region below the gate pad 8 also becomes the ineffective region 20C where the IGBT does not function.

[0189] Thus, like Embodiment 1 and Embodiment 2, Embodiment 3 has a control terminal 2 for the emitter electrode 3 and a control terminal for the gate as control terminals of the switching element, i.e., the IGBT, within the IGBT chip 1C.

[0190] The main current wiring 6 is electrically connected to the main current wiring 5 via a plurality of main current conductors 14, the emitter electrode 3, the IGBT within the IGBT chip 1C, the collector electrode 4, and the under-chip bonding material 17.

[0191] Therefore, in the operation of the IGBT within the IGBT chip 1C of the semiconductor device 53 of Embodiment 3, the main current flows as the collector current from the main current wiring 5 toward the main current wiring 6. The main current wirings 5 and 6 are external wirings for leading out the main current flowing through the IGBT. Figure 5 The current path IP3 shown indicates the current flow of the main current.

[0192] The semiconductor device 53 of Embodiment 3, like Embodiment 1 and Embodiment 2, is represented by the equivalent circuit shown in Figure 3 However, in Figure 3The main current wiring connection area 11 shown is replaced with the main current wiring connection area 11B.

[0193] Therefore, like the semiconductor device 51 and the second embodiment, the semiconductor device 53 of the third embodiment can also improve the reliability of the device.

[0194] The semiconductor device 53 of the third embodiment also achieves the following effects. Regarding the semiconductor device 52 of the second embodiment, in order to avoid interference between the control wire 7B and the plurality of main current wires 14, it is necessary to set the distance between the sensing connection point 25B of the control wire 7B and the chip connection point 23B of the main current wire 14 to be greater than or equal to a certain distance.

[0195] On the other hand, in the third embodiment, instead of the control wire 7B, the gate pad 8 and the emitter sensing pad 9 are used as the sensing connection components. Therefore, regarding the semiconductor device 53, even if the sensing connection point 25C is close to the chip connection point 23B, the above interference does not occur. Therefore, the distance between the chip connection point 23B and the sensing connection point 25C can be shortened, the emitter electrode resistance component R1 can be increased, and the effect of suppressing the amount of main current can be improved.

[0196] In this way, the semiconductor device 53 of the third embodiment can stably achieve the electrical connection with the emitter electrode 3 by connecting the emitter sensing wiring 10 at the sensing connection point 25C that is relatively close to the chip connection point 23B.

[0197] In addition, the IGBT chip 1C has an ineffective area 20C where the IGBT does not function in the area below the emitter sensing pad 9 and the emitter sensing wiring 10. Therefore, in the Figure 3 shown equivalent circuit, the emitter potential of the IGBT 62 is not affected by the main current.

[0198] Furthermore, regarding the above effects of the third embodiment, the emitter sensing wiring 10 corresponds to the "sensing wiring", the emitter electrode 3 corresponds to the "surface electrode", the IGBT chip 1C corresponds to the "semiconductor chip", the emitter sensing pad 9 corresponds to the "sensing pad", the emitter sensing wiring 10 corresponds to the "sensing wiring", and the IGBT corresponds to the "switching element".

[0199] In addition, the emitter potential of the IGBT 62 becomes the control reference potential obtained from the emitter sensing pad 9.

[0200] <Embodiment 4>

[0201] Figure 6 And Figure 7 are explanatory diagrams showing the structure of the semiconductor device 54 according to the fourth embodiment of the present invention.Figure 6 The upper figure above is a sectional view, and the lower figure is a top view. Figure 7 is a top view. Figure 6 The E-E section of the lower figure of Figure 6 becomes the upper figure of Figure 7 The F-F section of Figure 6 also becomes the upper figure of Figure 6 In the upper figure and the lower figure of Figure 7 the XYZ orthogonal coordinate system is respectively marked.

[0202] Figure 6 The lower figure of Figure 7 is a top view with the uppermost part being the insulating film 12.

[0203] In Figure 6 and Figure 7 the semiconductor device 54 shown uses an IGBT as a switching element, and an IGBT chip, namely an IGBT chip 1D, having an IGBT inside is packaged.

[0204] Hereinafter, parts identical to those of the semiconductor device 51 of Embodiment 1 shown in Figure 1 and Figure 2 are denoted by the same reference numerals and description thereof is appropriately omitted, and description will be centered on the characteristic parts of the semiconductor device 54. In addition, Figure 6 and Figure 7 the current path IP4 shown shows the current flow of the main current.

[0205] The semiconductor device 54 of Embodiment 4 has the following characteristics (5) to (7) in addition to the characteristics (1) to (3) of the semiconductor device 51.

[0206] (5) The IGBT chip 1D further has a current detection IGBT that performs an on / off operation equivalent to that of the original IGBT, and the current detection IGBT is provided in the current detection element formation region 27 of the IGBT chip 1D.

[0207] (6) It further has a current detection output pad 15, and the current detection output pad 15 is provided on the surface of the current detection element formation region 27 of the IGBT chip 1D so as not to contact the emitter electrode 3, and a detection current flows during the operation of the current detection IGBT.

[0208] (7) The current obtained from the current detection output pad 15 becomes the sense current Is.

[0209] In addition, regarding the above characteristics (5) to (7), the IGBT chip 1D corresponds to the "semiconductor chip", the IGBT corresponds to the "switching element", the IGBT for current detection corresponds to the "current detection element", the emitter electrode 3 corresponds to the "surface electrode", and the current detection output pad 15 corresponds to the "pad for current detection".

[0210] In addition, similar to Embodiment 1, structural elements of the IGBT are not formed in the inactive region 20D below the emitter sense pad 9 and the emitter sense wiring 10. This inactive region 20D becomes a region where the switching element, i.e., the IGBT, does not function.

[0211] Moreover, in the IGBT chip 1D, the region below the gate pad 8 also becomes the inactive region 20D where the IGBT does not function.

[0212] In addition, in the IGBT chip 1D, an inactive region 20D is also formed around the current detection element formation region 27. Since the inactive region 20D functions as an element isolation region, the IGBT for current detection in the current detection element formation region 27 is provided independently of the original IGBT below the emitter electrode 3.

[0213] The current detection output pad 15 is provided above the current detection element formation region 27 so as not to contact the emitter electrode 3, the gate pad 8, and the emitter sense pad 9, and functions as the emitter electrode of the IGBT for current detection. As shown in the upper figure Figure 6 above, it is electrically connected to the control terminal 2D via the control wire 7D. In this way, the current detection output pad 15 is provided independently of the emitter electrode 3.

[0214] Figure 8 is a circuit diagram showing the equivalent circuit of the semiconductor device 54 shown in Figure 6 and Figure 7 above. In Figure 8 above, the resistance component of the emitter electrode 3 is considered. In addition, in Figure 8 above, the gate pad 8 is represented by "G", the emitter sense pad 9 is represented by "Es", and the current detection output pad 15 is represented by "S".

[0215] For simplicity, in Figure 8 above, the resistance component R1 of the emitter electrode is considered as a lumped constant. That is, the IGBTs in the IGBT chip 1D are classified into two. The IGBT through which the collector current Ic2 flows in the main current wiring connection region 11 and its vicinity is set as the IGBT 62, and the IGBT through which the collector current Ic1 flows in the outer peripheral region of the emitter electrode 3 separated from the main current wiring connection region 11 is set as the IGBT 61. This outer peripheral region becomes a region where the surface electrode is far away.

[0216] Figure 11 This is a circuit diagram showing an equivalent circuit of a comparative semiconductor device 59B that has a current detection function in the same way as the semiconductor device 54. The semiconductor device 59B has a structure in which a current detection output pad 15 is added to the semiconductor device 59 of the basic technology shown in Figure 9 and Figure 10 . In addition, in Figure 11 , the gate pad 38 is represented by "G", the emitter sense pad 39 is represented by "Es", and the current detection output pad 15 is represented by "S".

[0217] In Figure 11 , the emitter electrode resistance component R9 is considered as a lumped constant. That is, the IGBTs of the IGBT chip 31 are classified into two. The IGBT through which the collector current Ic2 flows in the main current wiring connection region 41 and its vicinity is set as the IGBT62, and the IGBT through which the collector current Ic1 flows in the emitter sense pad 39 and its vicinity is set as the IGBT 61.

[0218] In addition, in Figure 8 and Figure 11 , the current detection IGBT is commonly set as the IGBT 63. The gate of the IGBT 63 is connected to the gate pad 8, and the emitter is connected to the current detection output pad 15 without passing through the emitter electrode resistance component R1 or R9. Here, the current flowing through the IGBT 63 is set as the sense current Is.

[0219] Furthermore, to simplify the explanation, the current detection output pad 15 is short-circuited with the emitter sense pad 9 or the emitter sense pad 39.

[0220] Similar to the equivalent circuit of the semiconductor device 59 shown in Figure 10 , the semiconductor device 59B is affected by the emitter electrode resistance component R9, and the collector current Ic2 of the IGBT 62 has a tendency to increase.

[0221] On the other hand, neither the gate voltage VGE1 of the IGBT 61 nor the gate voltage VGE3 of the IGBT 63 is affected by the emitter electrode resistance component R9.

[0222] Therefore, if the voltage value of the original gate-emitter voltage of the IGBT in the IGBT chip 31 is set as the control voltage value VG0, both the gate voltage VGE1 and the gate voltage VGE3 are equal to the control voltage value VG0.

[0223] Therefore, for the semiconductor device 59B, the collector current Ic1 and the sense current Is are not affected by the increase in the collector current Ic2.

[0224] That is, the semiconductor device 59B has a detection characteristic that can accurately detect the collector current Ic1 through the sense current Is, but cannot accurately detect the collector current Ic2 through the sense current Is.

[0225] Therefore, for the semiconductor device 59B, when the main current (= Ic1 + Ic2) of the IGBT increases, as the current ratio of the collector current Ic2 in the main current increases, the detection sensitivity of the main current based on the sense current Is decreases.

[0226] On the other hand, the semiconductor device 54 of Embodiment 4 is similarly affected by the emitter electrode resistance component R1 as the semiconductor device 51, and the collector current Ic1 of the IGBT 61 has a tendency to decrease.

[0227] On the other hand, the semiconductor device 54 is the same as the semiconductor device 51, and the gate voltage VGE2 of the IGBT 62 is not affected by the emitter electrode resistance component R1.

[0228] Moreover, the gate voltage VGE3 of the IGBT 63 is also not affected by the emitter electrode resistance component R1. The reason is that the current detection output pad 15 is formed above the current detection element formation region 27, and the current detection output pad 15 can be formed relatively small. Therefore, the gate voltage VGE3 when the current detection IGBT operates is hardly affected by the resistance component of the current detection output pad 15.

[0229] Therefore, if the voltage value of the original gate-emitter voltage of the IGBT in the IGBT chip 1D is set as the control voltage value VG0, both the gate voltage VGE2 and the gate voltage VGE3 are equal to the control voltage value VG0.

[0230] Therefore, for the semiconductor device 54 of Embodiment 4, the collector current Ic2 and the sense current Is are not affected by the decrease in the collector current Ic1.

[0231] The semiconductor device 54 has a detection characteristic that can accurately detect the collector current Ic2 through the sense current Is, but cannot accurately detect the collector current Ic1 through the sense current Is.

[0232] Therefore, for the semiconductor device 54 of Embodiment 4, when the main current (= Ic1 + Ic2) of the IGBT increases, the current ratio of the collector current Ic1 in the main current decreases, and as the current ratio of the collector current Ic2 increases, the detection sensitivity of the main current based on the sense current Is relatively increases.

[0233] In the semiconductor device 54 of Embodiment 4, when the main current flows through the emitter electrode 3 of the IGBT, the gate voltage VGE1 is lower than the gate voltage VGE2, and the amount of the collector current Ic1 flowing through the region far from the surface electrode decreases.

[0234] On the other hand, since the gate voltage VGE1 and the gate voltage VGE3 are not affected by the emitter electrode resistance component R1, even if the collector current Ic1 decreases, the collector current Ic2 and the sense current Is do not decrease.

[0235] As a result, the amount of the collector current Ic1 flowing through the region far from the surface electrode in the main current flowing through the IGBT in the IGBT chip 1D decreases, and the detection sensitivity of the main current based on the sense current Is flowing through the current detection IGBT can be improved correspondingly as the ratio of the collector current Ic2 in the main current increases.

[0236] Regarding the effects of the above Embodiment 4, the IGBT corresponds to the "switching element", and the emitter electrode 3 corresponds to the "surface electrode". In addition, when the original IGBT in the IGBT chip 1D is classified into IGBTs 61 and 62, the gate voltage VGE1 corresponds to the "control voltage" for the IGBT 61, and the gate voltage VGE2 corresponds to the "control voltage" for the IGBT 62. Also, the current detection output pad 15 corresponds to the "current detection pad", and the gate voltage VGE3 corresponds to the "control voltage" for the IGBT 63.

[0237] In addition, as the semiconductor device 54 of Embodiment 4, a structure in which the current detection output pad 15 and the current detection element formation region 27 are added based on the semiconductor device 51 is shown. Without being limited to this structure, a structure in which the current detection output pad 15 and the current detection element formation region 27 are added based on the semiconductor device 52 or the semiconductor device 53 may be adopted as a modified example. In the modified example of Embodiment 4, the inherent effects of Embodiment 4 can be similarly achieved.

[0238] <Others>

[0239] Regarding the semiconductor devices 51 to 54 of Embodiments 1 to 4, an IGBT is used as the switching element. By using an IGBT as the switching element, the following effects are obtained. Hereinafter, the semiconductor device 51 of Embodiment 1 will be described as a representative.

[0240] The IGBT provided in the IGBT chip 1 of the semiconductor device 51 has a PN junction, and always generates a loss in an amount of the turn-on voltage (1VF≈0.7V) when energized. Here, "VF" refers to the forward voltage of the diode, and a loss in an amount of 1VF is generated between the emitter electrode 3 and the collector electrode 4.

[0241] Therefore, even if there is a loss caused by the minute emitter electrode resistance component R1 of the surface electrode, i.e., the emitter electrode 3, the loss of the above-mentioned 1VF amount caused by the turn-on voltage is dominant. Therefore, in the case of the semiconductor device 51, even if the emitter electrode resistance component R1 is designed to be large, it is easy to allow an increase in loss, and the reliability of the device can be further improved.

[0242] In this way, in the case where an IGBT is used as the switching element provided in the IGBT chip 1, the IGBT has the characteristic that the turn-on voltage during energization is not easily affected by the loss caused by the emitter electrode resistance component R1 of the emitter electrode 3. Therefore, a highly reliable semiconductor device 51 can be obtained.

[0243] In addition, in addition to the IGBT, other semiconductor elements such as MOSFETs can also be used as the switching element. As the constituent material of the MOSFET, for example, silicon (Si) or silicon carbide (SiC) is considered. Even in this case, the effects shown in Embodiments 1 to 4 can be exhibited.

[0244] In addition, switching elements typified by IGBTs are usually formed of silicon (Si), but as a modification, it is conceivable to form the switching element of a wide-bandgap semiconductor having a larger bandgap than silicon. As the wide-bandgap semiconductor, for example, there are silicon carbide, gallium nitride-based materials, or diamond.

[0245] Hereinafter, as a semiconductor device having a switching element composed of a wide-bandgap semiconductor, a modification of the semiconductor device 51 of Embodiment 1 will be described as a representative.

[0246] In a modification of the semiconductor device 51, an IGBT is composed of a wide-bandgap semiconductor. The IGBT has high breakdown voltage and high allowable current density, so the miniaturization of the IGBT can be achieved. Therefore, the modification of the semiconductor device 51 obtains the effect of being able to miniaturize the device as a semiconductor module by disposing the miniaturized IGBT in the IGBT chip 1.

[0247] In addition, the wide-bandgap semiconductor also has high heat resistance, so the miniaturization of the heat dissipation fins of the radiator and the air cooling of the water cooling part can be achieved. Therefore, in the case of the modification of the semiconductor device 51, as a semiconductor module, further miniaturization can be achieved.

[0248] In this way, the IGBT in the modification of the semiconductor device 51 is composed of a wide-bandgap semiconductor. As described above, the wide-bandgap semiconductor has the characteristics of high breakdown voltage, high allowable power density, and high heat resistance. Therefore, the modification of the semiconductor device 51 can achieve device miniaturization.

[0249] In addition, due to the low power loss of the wide-bandgap semiconductor, the high efficiency of the IGBT element can be achieved, and further the high efficiency of the semiconductor module having the IGBT can be achieved. According to the above-mentioned high heat resistance and low loss characteristics, it is easy to allow an increase in the deterioration of the loss caused by the emitter electrode resistance component R1 of the emitter electrode 3.

[0250] In this way, the modified example of the semiconductor device 51 can exhibit the above various effects. In addition, the IGBT in the above effects corresponds to the "switching element", the IGBT chip 1 corresponds to the "semiconductor chip", and the emitter electrode 3 corresponds to the "surface electrode".

[0251] In addition, switching elements typified by the IGBTs provided in the IGBT chips 1, 1B to 1D can be applied regardless of whether they are planar or trench type.

[0252] In addition, the embodiments can be freely combined within the scope of the present invention, or the embodiments can be appropriately modified or omitted.

[0253] Description of reference numerals

[0254] 1, 1B to 1D IGBT chips, 2 control terminals, 3 emitter electrodes, 4 collector electrodes, 5, 6 main current wirings, 7, 7B control wires, 8 gate pads, 9 emitter sense pads, 10 emitter sense wirings, 11 main current wiring connection regions, 12 insulating films, 13 on-chip bonding materials, 14 main current wires, 15 current detection output pads, 20, 20C, 20D inactive regions, 27 current detection element formation regions.

Claims

1. A semiconductor device having: A semiconductor chip having switching elements therein; and A surface electrode provided on the surface of the semiconductor chip, through which a main current flows during the operation of the switching element, The switching element has a control electrode, and the switching element is controlled to operate by applying a control voltage having the potential of the surface electrode as a reference potential to the control electrode, The semiconductor device further has an insulating film provided on the surface electrode, The insulating film has an opening region, and in the surface electrode, the region within the opening region becomes a wiring connection region, The semiconductor device further has: A chip bonding material having a lower surface, and the lower surface of the chip bonding material contacts the surface of the wiring connection region, whereby the chip bonding material is electrically connected to the surface electrode; A sense pad independently provided on the surface of the semiconductor chip with respect to the surface electrode; and A sense wiring provided on the surface of the semiconductor chip, electrically connecting the surface electrode and the sense pad, The potential of the sense pad becomes the reference potential for controlling the switching element, The lower surface of the chip bonding material has a shape that conforms to the surface shape of the wiring connection region when viewed from above, The sense wiring is connected to the wiring connection region, The semiconductor chip has an inactive region below the sense pad and the sense wiring where the switching element does not function.

2. A semiconductor device having: A semiconductor chip having a switching element inside; and A surface electrode provided on the surface of the semiconductor chip, through which a main current flows during the operation of the switching element, The switching element has a control electrode, and the switching element is controlled to operate by applying a control voltage having the potential of the surface electrode as a reference potential to the control electrode, The semiconductor device further has: A chip wire electrically connected to the surface electrode by contacting at a chip connection point on the surface of the surface electrode; and A sense connection component electrically connected to the surface electrode by contacting at a sense connection point of the surface electrode, The potential of the sense connection point becomes the reference potential for controlling the switching element. At the surface electrode, the region including the chip connection point is defined as a wiring connection region, and at the surface electrode, the position farthest from the wiring connection region is defined as an electrode remote position, The sense connection point satisfies the connection point arrangement condition of being provided at a position closer to the chip connection point among the chip connection point and the electrode remote position, The sense connection component includes: A sense pad independently provided on the surface of the semiconductor chip with respect to the surface electrode; and A sense wiring provided on the surface of the semiconductor chip, electrically connecting the surface electrode and the sense pad, The sense connection point exists on the side of the wiring connection region, The sense wiring is electrically connected to the surface electrode by contacting the surface electrode at the sense connection point, The semiconductor chip has a non-effective region where the switching element does not function in a region below the sense pad and the sense wiring.

3. The semiconductor device according to claim 2, wherein, the wire for chip includes a plurality of wires for chip, the sense connection point satisfies the connection point arrangement condition in relation to at least one of the plurality of wires for chip.

4. The semiconductor device according to any one of claims 1 to 3, wherein, the semiconductor chip further has a current detection element which is provided independently of the switching element and performs an on / off operation equivalent to that of the switching element, and the current detection element is provided in a current detection element formation region of the semiconductor chip. The semiconductor device further has: a current detection pad which is provided independently of the surface electrode above the current detection element formation region of the semiconductor chip and through which a detection current flows when the current detection element operates.

5. The semiconductor device according to any one of claims 1 to 3, wherein, the switching element is an IGBT.

6. The semiconductor device according to claim 4, wherein, the switching element is an IGBT.

7. The semiconductor device according to any one of claims 1 to 3, wherein, the switching element is made of a wide bandgap semiconductor.

8. The semiconductor device according to claim 4, wherein, the switching element is made of a wide bandgap semiconductor.

9. The semiconductor device according to claim 5, wherein, the switching element is made of a wide bandgap semiconductor.

10. The semiconductor device according to claim 6, wherein, the switching element is made of a wide bandgap semiconductor.

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