JP7784972B2 - Semiconductor device and manufacturing method thereof - Google Patents

Description

The present invention relates to a semiconductor device equipped with a power element and a manufacturing method thereof.

In recent years, power conversion devices using semiconductor devices (semiconductor modules) equipped with SiC (silicon carbide) power semiconductor chips have begun to appear on the market. Wide bandgap power semiconductors, such as SiC, have lower conduction losses than conventional Si (silicon) power semiconductors, making it possible to create compact semiconductor modules using small semiconductor chips. However, as chip size decreases, the chip's heat dissipation area also decreases, and thermal resistance tends to increase. Furthermore, depending on the power conversion device, a chip temperature detection function may be required to protect against overheating, requiring more precise temperature management of the semiconductor module.

Patent document 1 (JP 2022-78954 A) describes a chip package that includes a chip equipped with a chip temperature sensor at the end of its underside, and a carrier that is connected to the underside of the chip via solder balls and equipped with a carrier temperature sensor on the surface facing the chip temperature sensor.

Patent Document 2 (JP 2016-163535 A) describes a package that has a transistor equipped with a temperature sensor and a diode, and is cooled by a cooler supplied with a cooling medium. In this package, the transistor equipped with the temperature sensor is placed on the upper side to quickly detect a decrease in cooling function when the cooling medium decreases.

Patent document 3 (JP 2016-115727 A) describes a method in which a first semiconductor chip equipped with a power semiconductor is stacked and bonded to another second semiconductor chip, and a heat detection circuit is provided on the top surface of the second semiconductor chip directly below the first semiconductor chip.

Japanese Patent Application Laid-Open No. 2022-78954 JP 2016-163535 A JP 2016-115727 A

As a temperature detection function for overheat protection, a method of forming a temperature sensor within a semiconductor chip has been proposed, as in Patent Document 1. However, when a temperature sensor is formed within a power semiconductor chip, the active area is reduced, increasing loss and therefore the amount of heat generated by the semiconductor chip. Furthermore, as in Patent Documents 2 and 3, methods have been proposed in which a temperature sensor is mounted directly above or below the semiconductor chip, but this does not take into consideration heat dissipation from the semiconductor chip, raising concerns that the thermal resistance of the semiconductor chip may increase significantly.

The object of the present invention is to provide a semiconductor device with a highly accurate temperature detection function while suppressing an increase in thermal resistance.

Other objects and novel features will become apparent from the description of this specification and the accompanying drawings.

A brief overview of representative embodiments disclosed in this application is as follows:

One embodiment of the semiconductor device includes a semiconductor chip having a main surface covered with a first electrode and including a semiconductor element; a main terminal bonded to a portion of the first electrode via a conductive first bonding material and electrically connected to the semiconductor element; multiple sense terminals insulated from the main terminal and the first electrode, spaced apart from the main terminal in a plan view, and thinner than the main terminal; a temperature sensor having a first surface connected to the semiconductor chip-facing surface of each of the multiple sense terminals via a conductive second bonding material; and resin covering portions of the main terminal, the multiple sense terminals, the first electrode, and the temperature sensor, covering a portion of the first surface of the temperature sensor, and interposed between the temperature sensor and the first electrode. The temperature sensor and multiple sense terminals overlap the semiconductor chip in a plan view.

One embodiment of a method for manufacturing a semiconductor device includes the following steps: (a) preparing a support; a semiconductor substrate including a conductor including a first convex portion formed on the support and a plurality of second convex portions each shorter than the first convex portions; a surface electrode covering a main surface; and a semiconductor element electrically connected to the surface electrode; and a temperature sensor; (b) bonding the upper surfaces of the plurality of second convex portions to the temperature sensor via a conductive second bonding material; (c) bonding the upper surfaces of the first convex portions to the surface electrode via a conductive first bonding material; (d) after steps (b) and (c), embedding resin between the conductor and the semiconductor substrate and the surface electrode; and (e) after step (d), removing the support to expose a portion of the resin. The surface of the temperature sensor opposite the semiconductor substrate is covered with the second bonding material and the resin.

The effects achieved by representative inventions disclosed in this application can be briefly explained as follows:

This invention provides a semiconductor device with a highly accurate temperature detection function while suppressing increases in thermal resistance.

1 is a plan view showing a semiconductor device according to a first embodiment; FIG. 2 is a cross-sectional view taken along line AA in FIG. 1A to 1C are cross-sectional views illustrating a method for manufacturing a semiconductor device according to a first embodiment. 4 is a cross-sectional view illustrating the method of manufacturing the semiconductor device following FIG. 3. 5 is a cross-sectional view illustrating the method of manufacturing the semiconductor device following FIG. 4. 6 is a cross-sectional view illustrating the method of manufacturing the semiconductor device following FIG. 5. 7A to 7C are cross-sectional views illustrating the method of manufacturing the semiconductor device following FIG. 6. FIG. 1 is a cross-sectional view showing a semiconductor device according to a first modification of the first embodiment. 10A to 10C are cross-sectional views illustrating a method for manufacturing a semiconductor device according to a second modification of the first embodiment. 10A to 10C are cross-sectional views illustrating the method of manufacturing the semiconductor device following FIG. 9. 11 is a cross-sectional view illustrating the method of manufacturing the semiconductor device subsequent to FIG. 10. 12 is a cross-sectional view illustrating the method of manufacturing the semiconductor device following FIG. 11 . FIG. 10 is a plan view showing a semiconductor device according to a second embodiment; 14 is a cross-sectional view taken along line BB in FIG. 13. 14 is a cross-sectional view taken along line CC in FIG. 13. FIG. 10 is an enlarged cross-sectional view showing a part of a semiconductor device according to a second embodiment. FIG. 2 is a plan view showing the temperature distribution of the semiconductor device. FIG. 10 is a cross-sectional view showing a semiconductor device which is a modification of the second embodiment. FIG. 10 is a cross-sectional view showing a semiconductor device which is a modification of the second embodiment.

Embodiments of the present invention will be described in detail below with reference to the drawings. In all drawings used to explain the embodiments, components having the same functions will be given the same reference numerals, and repeated explanations will be omitted. Furthermore, in the following embodiments, as a general rule, explanations of identical or similar parts will not be repeated unless particularly necessary. Furthermore, in the drawings used to explain the embodiments, hatching may be used even in plan views or perspective views to make the configuration easier to understand. Furthermore, in the drawings used to explain the embodiments, hatching may be omitted in cross-sectional views to make the configuration easier to understand.

<Details of areas for improvement>
First, we will explain in detail the room for improvement regarding semiconductor devices equipped with temperature sensors. Among the semiconductor chips used in semiconductor modules, SiC power semiconductor chips, particularly those using SiC (silicon carbide) substrates, can be made smaller in size than Si (silicon) power semiconductor chips. In this case, the heat dissipation area of the semiconductor chip is also reduced, which may increase thermal resistance. Therefore, a temperature detection function for the semiconductor chip may be essential in some cases to protect the semiconductor chip from malfunction or destruction due to excessive temperature rise of the semiconductor chip.

In a semiconductor module capable of detecting the temperature of a semiconductor chip, it is possible to install a temperature sensor at a position away from the semiconductor chip in the lateral direction (along the main surface of the semiconductor chip). However, in this case, there is room for improvement in the first area: low temperature detection accuracy.

It is also possible to form an element used as a temperature sensor on the semiconductor chip to detect the temperature of the semiconductor chip. This temperature sensor is, for example, a sense element with a structure similar to the main MOSFET (Metal Oxide Semiconductor Field Effect Transistor) provided on the semiconductor chip. However, in this case, providing the sense element on the semiconductor substrate reduces the active area (the main element formation area different from the sense element) and increases loss, which means there is room for a second improvement: an increase in the amount of heat generated by the semiconductor chip.

In addition, to detect the temperature of a semiconductor chip, it is possible to place a temperature sensor so that it overlaps the semiconductor chip in a direction perpendicular to the main surface of the semiconductor chip, i.e., directly above or below the semiconductor chip. In this case, the temperature sensor may be sandwiched between the semiconductor chip and another substrate, etc., which may increase the thermal resistance of the temperature sensor. Therefore, some ingenuity is needed to improve the heat dissipation performance of the temperature sensor. In other words, there is a third area of improvement where cooling performance may be reduced if the semiconductor chip and temperature sensor are overlapped.

As such, there is room for improvement in semiconductor devices equipped with temperature sensors, such as improving the accuracy of temperature detection by providing a temperature sensor, preventing an increase in the amount of heat generated by the semiconductor chip, and preventing an increase in the thermal resistance of the temperature sensor.

The embodiments of the present application therefore incorporate measures to address the aforementioned room for improvement. The following describes the technical concept of these ingenious embodiments.

(Embodiment 1)
A semiconductor device having a semiconductor chip and a temperature sensor will be described below with reference to the drawings.

<Structure of semiconductor device>
The structure of a chip, which is a semiconductor device according to the first embodiment, will be described with reference to FIGS. 1 and 2. As shown in FIG. 1, the planar shape of chip 1 is rectangular. Chip 1 has a main surface (top surface) and a back surface (bottom surface) on the opposite side. In plan view, a main terminal (source pad) 5, a control terminal (gate pad, third main terminal) 6, and two sense terminals (sense pads) 7 and 8 are exposed on the main surface of chip 1. In plan view, resin 12 surrounding each of main terminal 5, control terminal 6, and sense terminals 7 and 8 is exposed. In plan view, sense terminals 7 and 8 are spaced apart from main terminal 5 and control terminal 6.

Figure 2 shows a cross section taken along line A-A in Figure 1, i.e., a cross section including the main terminal 5 and the sense terminals 7 and 8. As shown in Figure 2, chip 1 has a semiconductor chip 2 with a main surface (top surface) and an opposite back surface (bottom surface). The main surface of semiconductor chip 2 is covered with a first surface electrode 3 and a second surface electrode (not shown), and the back surface of semiconductor chip 2 is covered with a back surface electrode 4. In Figure 2, the only electrode covering the main surface of semiconductor chip 2 is the first surface electrode (source electrode, source wiring) 3. However, in reality, a second surface electrode (gate electrode, gate wiring) separate from the first surface electrode 3, which is not shown, also covers the main surface of semiconductor chip 2. The second surface electrode is separated from the first surface electrode 3, and these electrodes are insulated from each other. The first surface electrode 3 and the second surface electrode are primarily made of, for example, Ni (nickel) or Al (aluminum), and the back surface electrode 4 is primarily made of, for example, Ti (titanium), Ni, or Au (gold). Each of the first surface electrode 3, second surface electrode, and back surface electrode 4 may not be made of only one of the above-mentioned materials, but may be a laminate film composed of a layer of that material and another metal layer.

A main terminal 5 is formed directly above the first surface electrode 3 via a bonding material 10. The main terminal 5 is bonded to the first surface electrode 3 via the conductive bonding material 10. The main terminal 5 is electrically connected to the first surface electrode 3 via the bonding material 10. In addition, in an area not shown, a control terminal 6 is formed directly above the second surface electrode (gate electrode) and bonded via a bonding material. The control terminal 6 is electrically connected to the second surface electrode via the bonding material. The bonding material is made of, for example, solder or a conductive sintered material.

A temperature sensor (sense element) 9 is provided on the main surface of the semiconductor chip 2, spaced apart from the first surface electrode 3 and the second surface electrode. A portion of the top surface of the temperature sensor 9 is connected to the surface (bottom surface) of the sense terminal 7 facing the semiconductor chip 2 via a conductive bonding material 11. Another portion of the top surface of the temperature sensor 9 is connected to the surface (bottom surface) of the sense terminal 8 facing the semiconductor chip 2 via another bonding material 11. In other words, the temperature sensor 9 is electrically connected to each of the sense terminals 7 and 8 via the bonding material 11. The main terminal 5, control terminal 6, and sense terminals 7 and 8 are each made of, for example, Cu, W (tungsten), Al, or Mo (molybdenum). The bonding material 11 is made of, for example, solder, silver paste, or a conductive sintered material.

The main terminal 5, control terminal 6, and sense terminals 7 and 8 are spaced apart from one another. The height of the top surfaces of the main terminal 5, control terminal 6, and sense terminals 7 and 8 are the same. Here, "height" refers to the distance from the main surface of the semiconductor chip 2 in a direction perpendicular to the main surface of the semiconductor chip 2 (height direction, thickness direction, vertical direction). The main terminal 5, control terminal 6, and first surface electrode 3 are insulated from the sense terminals 7 and 8. The thickness of the temperature sensor 9 and sense terminals 7 and 8 is smaller than the thickness of the main terminal 5 and control terminal 6.

The main surface of the semiconductor chip, the top surface of the first surface electrode 3, and a portion of the top surface of the second surface electrode are covered with resin 12. Resin 12 covers the side surfaces of bonding materials 10, 11, main terminal 5, control terminal 6, and sense terminals 7 and 8. Resin 12 covers a portion of the top surface, the entire side surfaces, and the entire bottom surface of temperature sensor 9. In other words, resin 12, which is an insulator, is interposed between the first surface electrode 3 and temperature sensor 9 in the height direction. The surface of the top surface of the first surface electrode 3 that is exposed from the bonding material 10 is covered with resin 12. The surface of the top surface of the second surface electrode that is exposed from the bonding material is covered with resin 12. The temperature sensor 9 and sense terminals 7 and 8 are located at the same height as the main terminal 5 and control terminal 6.

The semiconductor chip 2 has a semiconductor substrate. The semiconductor substrate is mainly _made of, for example, Si (silicon), SiC (silicon carbide), GaN (gallium nitride), or _Ga2O3 (gallium oxide). The semiconductor chip 2 has a semiconductor element. The semiconductor element has at least a portion of its components and a current path within the semiconductor substrate. Examples of the semiconductor element include a MOSFET and a diode. In this embodiment, a case where a MOSFET is formed on the semiconductor chip 2 will be described. A MOSFET is a vertical element that has a source region and a gate electrode on the main surface side of the semiconductor substrate and a drain region on the back surface side of the semiconductor substrate. If the semiconductor element is only a diode, the control terminal 6 and the second surface electrode are not necessary.

Although not specifically shown, the semiconductor chip 2 has a semiconductor substrate, an interlayer insulating film on the semiconductor substrate, and multiple contact plugs that penetrate the interlayer insulating film. The first surface electrode 3 is electrically connected to the source region of the MOSFET via the contact plug. That is, the main terminal 5 is electrically connected to the semiconductor element via the bonding material 10, the first surface electrode 3, and the contact plug. The second surface electrode is electrically connected to the gate electrode of the MOSFET via another contact plug. The back surface electrode 4 is a drain electrode electrically connected to the drain region of the MOSFET. If the semiconductor element is only a diode, for example, the first surface electrode 3 is an anode electrode and the back surface electrode 4 is a cathode electrode.

The temperature sensor 9 is, for example, a thermistor, which is a two-terminal element. A thermistor is a temperature sensor that utilizes the change in resistance value when it detects heat. The temperature of the chip 1 can be detected by utilizing the thermistor's characteristic that its resistance value decreases as the temperature increases and increases as the temperature decreases. In this way, the temperature sensor 9 does not need to be an element that directly detects temperature, as long as it is an element that can indirectly detect temperature. Instead of a thermistor, the temperature sensor 9 may also be, for example, a strain sensor.

As shown in FIG. 1, the main terminal 5 is a main current terminal that has a larger area than the other control terminal 6 and sense terminals 7 and 8 in a planar view. In other words, when the chip 1 is operating, a larger current flows through the main terminal 5 than through the other control terminal 6 and sense terminals 7 and 8. As shown in FIGS. 1 and 2, the temperature sensor 9 is located at the end of the chip 1 in a planar view, but it may be located anywhere on the chip 1 in a planar view. Furthermore, the number of temperature sensors 9 is not limited to one, and may be two or more. The sense terminals 7 and 8 shown in FIG. 1 have different lengths, but the lengths of the sense terminals 7 and 8 are not limited to this and can be freely changed. Although only one control terminal 6 is shown in FIG. 1, the number of control terminals 6 may be two or more.

<Method of manufacturing semiconductor device>
Next, a method for manufacturing the semiconductor device according to this embodiment will be described with reference to FIGS.

First, as shown in Figure 3, a plate-shaped support 13 is prepared, having first convex portions (main terminal 5 and control terminal 6) (see Figure 1) and second convex portions (sense terminals 7 and 8) on its upper portion. The main terminal 5, control terminal 6, and sense terminals 7 and 8 are formed by processing a single conductor and are integrated with the support 13. The main terminal 5 and control terminal 6 are convex portions that are higher from the top surface of the support than the sense terminals 7 and 8. In other words, the conductor including the main terminal 5, control terminal 6, sense terminals 7 and 8, and support 13 has an upper surface with three levels of height: the upper surfaces of the main terminal 5 and control terminal 6, the upper surfaces of the sense terminals 7 and 8, and the upper surface of support 13.

The conductor can be separated into multiple chips in a later process by cutting it. The conductor has multiple chip regions that will become chips in a later process, and each chip region has a main terminal 5, control terminal 6, and sense terminals 7 and 8 formed therein. The conductor is made of, for example, Cu, W, Al, or Mo.

Although not shown, a semiconductor wafer 2a is prepared which has a first surface electrode 3 (see Figure 2) and a second surface electrode on its main surface and a back surface electrode 4 on its back surface. The semiconductor wafer 2a has a semiconductor substrate and a semiconductor element.

Next, as shown in FIG. 4, a temperature sensor 9 is connected to the upper surfaces of sense terminal 7 and sense terminal 8 so as to straddle them. The temperature sensor 9 is connected to sense terminal 7 and sense terminal 8 with a bonding material 11. Next, the semiconductor wafer 2a is connected to the upper surfaces of the main terminal 5 and control terminal 6 using a bonding material 10. Specifically, the main terminal 5 is connected via the bonding material 10 to a first surface electrode 3 formed in contact with the main surface of the semiconductor wafer 2a, and the control terminal 6 is connected via the bonding material to a second surface electrode (not shown) formed in contact with the main surface of the semiconductor wafer 2a. The support 13 and temperature sensor 9 are spaced apart from the semiconductor wafer 2a.

Next, as shown in Figure 5, the space between the support 13 and the semiconductor wafer 2a is filled with resin 12 to seal it. At this time, the space between the temperature sensor 9 and the semiconductor wafer 2a is filled with resin 12, and the space between the temperature sensor 9 and the support 13 is also filled with resin 12.

Next, as shown in Figure 6, the bonded support 13 and semiconductor wafer 2a are turned upside down. The support 13 is then ground to remove the entire support 13 and expose the resin 12. At this time, the sense terminals 7 and 8 and the resin 12 between them are left, preventing the temperature sensor 9 from being exposed. In other words, the surface of the temperature sensor 9 opposite the semiconductor wafer 2a side (semiconductor substrate side) is covered with the bonding material 11 and resin 12.

Next, as shown in Figure 7, a dicing process is performed to cut the spaces between each chip region, thereby dividing the semiconductor wafer 2a into individual pieces. This results in multiple semiconductor chips 2. Note that the second surface electrodes and control terminals 6 are not shown in Figure 7. The resin 12 is also cut during this dicing process. This allows the formation of a chip 1 having at least one semiconductor chip 2, one main terminal 5, one control terminal 6, one sense terminal 7, one 8, and one temperature sensor 9.

<Effects of this embodiment>
In this embodiment, the temperature sensor 9 shown in FIG. 2 is disposed between the semiconductor chip 2 and the sense terminals 7 and 8 and covered with resin 12, thereby enabling accurate temperature sensing while maintaining insulation between the semiconductor chip 2 and the temperature sensor 9. The temperature sensor 9 overlaps the semiconductor chip 2 in a plan view. In other words, the temperature sensor 9 is present within the chip area. This allows for highly accurate temperature detection. In other words, the first room for improvement, namely, low temperature detection accuracy, can be resolved.

In addition, by providing the temperature sensor 9 in a location separate from the semiconductor chip 2 rather than incorporating it into the semiconductor chip 2, a reduction in the active area of the semiconductor chip 2 is prevented, preventing an increase in loss. This prevents an increase in the amount of heat generated by the semiconductor chip. This eliminates the second area for improvement, which is an increase in the amount of heat generated by the semiconductor chip due to a reduction in the active area of the semiconductor chip.

In addition, the sense terminals 7 and 8 exposed from the chip 1 are provided at positions that overlap the semiconductor chip 2 in a planar view, preventing a decrease in the heat dissipation performance of the semiconductor chip 2. Furthermore, only the bonding material 11 is interposed between the temperature sensor 9 and the sense terminals 7 and 8, shortening the heat dissipation path from the temperature sensor 9. This prevents a decrease in the heat dissipation performance of the chip 1 due to the temperature sensor 9 being provided. This eliminates the third area for improvement, which is the potential decrease in cooling performance when the semiconductor chip and temperature sensor are overlapped. Furthermore, because resin 12 is filled between the temperature sensor 9 and the semiconductor chip 2, discharge between the temperature sensor 9 and the semiconductor chip 2 can be prevented.

Furthermore, as explained using Figures 3 to 7, the temperature sensor 9 is installed using the WLP (Wafer Level Packaging) process, which allows for more accurate alignment of the temperature sensor 9 than when a separate temperature sensor is installed on the chip, minimizing the increase in thermal resistance of the chip 1.

As a result, this embodiment provides a semiconductor device with a highly accurate temperature detection function while suppressing an increase in thermal resistance. In other words, the performance and reliability of the semiconductor device can be improved.

<Modification 1>
The temperature sensor and the sense terminal may be disposed on the back surface side of the semiconductor chip 2. Fig. 8 shows a cross-sectional view of a chip 14 which is a first modification of the first embodiment.

As shown in Figure 8, in this modified example, the main terminal 5a, bonding materials 10 and 11, resin 12, temperature sensor 9, and sense terminals 7 and 8 are formed under the back surface of the semiconductor chip 2, rather than on the main surface. The first surface electrode 3 is exposed to the outside of the chip 14 and forms a source pad, while the second surface electrode (not shown) is exposed to the outside of the chip 14 and forms a gate pad. Like the main terminal 5 shown in Figure 2, the main terminal 5a has a thickness greater than that of the temperature sensor 9 and sense terminals 7 and 8. The bottom surface of the main terminal 5a is exposed from the resin 12 and is located at the same height as the bottom surfaces of the sense terminals 7 and 8. The main terminal 5a is electrically connected to the back surface electrode 4 via bonding material 10 and serves as a drain pad. Here, the control terminal 6 (see Figure 1) is not formed.

The underside of the temperature sensor 9 is covered with the bonding material 11 and the resin 12, and the temperature sensor 9 is not exposed from the outside of the chip 14. In other words, the main terminal 5a, bonding materials 10, 11, resin 12, temperature sensor 9, and sense terminals 7 and 8 have a configuration similar to that of the main terminal 5, bonding materials 10, 11, resin 12, temperature sensor 9, and sense terminals 7 and 8 shown in Figure 2, but turned upside down.

Even with a structure like this modified example, the same effects as the semiconductor device described using Figures 1 and 2 can be obtained.

<Modification 2>
In the manufacturing process of the semiconductor device of this embodiment, semiconductor chips that have been separated in advance by a dicing process or the like may be connected to main terminals or the like on the upper part of the support body. A manufacturing method of the semiconductor device of this modification will be described below with reference to FIGS.

First, the same process as in Figure 3 is performed to prepare a conductor including a support 13 and a semiconductor wafer 2a including semiconductor elements. Next, the semiconductor wafer 2a is diced to separate the semiconductor wafer 2a, thereby obtaining multiple semiconductor chips 2. Also, a temperature sensor 9 (see Figure 9), such as a thermistor, is prepared.

Next, as shown in FIG. 9 , a temperature sensor 9 is connected to the upper surfaces of sense terminal 7 and sense terminal 8 so as to straddle these terminals. The temperature sensor 9 is connected to sense terminal 7 and sense terminal 8 by bonding material 11. Next, the semiconductor chip 2 is connected to the upper surfaces of the main terminal 5 and control terminal 6 (not shown) using bonding material 10. Specifically, the main terminal 5 is connected via bonding material 10 to a first surface electrode 3 formed in contact with the main surface of the semiconductor chip 2, and the control terminal 6 is connected via bonding material to a second surface electrode (not shown) formed in contact with the main surface of the semiconductor chip 2. Note that the second surface electrode and control terminal 6 are not shown in FIG. 9 .

Next, as shown in Figure 10, the space between the support 13 and the semiconductor chip 2 is filled with resin 12 to seal the device. At this time, the space between the temperature sensor 9 and the semiconductor chip 2 is filled with resin 12, and the space between the temperature sensor 9 and the support 13 is also filled with resin 12.

Next, as shown in Figure 11, the bonded support 13 and semiconductor chip 2 are turned upside down. The support 13 is then ground to remove the entire support 13 and expose the resin 12.

Next, as shown in Figure 12, a dicing process is performed to cut the resin 12 between each semiconductor chip 2, thereby obtaining multiple individual chips 15. This results in multiple semiconductor chips 2. As a result, a chip 15 is formed that has at least one semiconductor chip 2, one main terminal 5, one control terminal 6, one sense terminal 7, one 8, and one temperature sensor 9.

This modified example achieves the same effects as the semiconductor device described with reference to Figures 1 and 2. Furthermore, the semiconductor device manufacturing method of this modified example can improve the yield of semiconductor devices. Specifically, it is conceivable that some of the chip regions arranged on a semiconductor wafer may be defective. In this case, if the semiconductor wafer is connected to the conductors to form chips without dicing, the chips including the main terminals and temperature sensors connected to the defective chip regions will naturally be defective, resulting in a decrease in chip yield.

In contrast, in this modified example, the semiconductor wafer is diced to obtain the semiconductor chips 2 before connecting them to the conductors, so defective semiconductor chips 2 can be eliminated before connecting the semiconductor chips 2 to the conductors. Therefore, chips 15 can be formed using normal semiconductor chips 2 without wasting main terminals and temperature sensors, improving the yield of chips 15.

(Embodiment 2)
<Structure of semiconductor device>
The semiconductor device of this embodiment will be described below with reference to FIGS. 13 to 16. Here, differences from the first embodiment will be particularly described. As shown in FIG. 13, the planar shape of the chip 21 is rectangular. The chip 21 has a main surface (top surface) and a back surface (bottom surface) on the opposite side. In plan view, two main terminals (source pads) 5, a control terminal (gate pad, third main terminal) 6, a temperature sensor 9, and two sense terminals (sense pads) 7 and 8 are exposed on the main surface of the chip 21. In plan view, resin 12 surrounding each of the two main terminals 5 and the control terminal 6 is exposed. In plan view, each of both ends of the temperature sensor 9 is connected to the sense terminal 7 and the sense terminal 8, respectively. In plan view, the periphery of the pattern consisting of the temperature sensor 9 and the sense terminals 7 and 8 is covered with resin 12. In plan view, the temperature sensor 9 and the sense terminals 7 and 8 are spaced apart from the main terminal 5 and the control terminal 6.

Unlike the first embodiment, here the top surface of the temperature sensor 9 is exposed from the outside of the chip 21. In other words, the top surface, which is part of the temperature sensor, is exposed from the resins 12 and 17. Here, the temperature sensor 9 is located in the center of the chip 21 in a plan view.

Figure 14 shows a cross section taken along line B-B in Figure 13, i.e., a cross section including the main terminal 5, control terminal 6, and temperature sensor 9. Figure 15 shows a cross section taken along line C-C in Figure 13, i.e., a cross section including the main terminal 5 and sense terminals 7 and 8. As shown in Figures 14 and 15, chip 21 has a semiconductor chip 2. The main surface of semiconductor chip 2 is covered with a first surface electrode 3 and a second surface electrode 3a (shown only in Figure 14), and the back surface of semiconductor chip 2 is covered with a back surface electrode 4.

A main terminal 5 is formed directly above the first surface electrode 3 with a bonding material 10 interposed therebetween. A control terminal 6 is also formed directly above the second surface electrode 3a with a bonding material interposed therebetween. Unlike in the first embodiment, a groove-shaped recess 16 with a depth smaller than the thickness of the main terminal 5 is formed on the top surface of the main terminal 5, i.e., the surface opposite the semiconductor chip 2. The temperature sensor 9 and sense terminals 7 and 8 are formed within the recess 16 with resin 17 interposed therebetween. In other words, within the recess 16, resin 17 is interposed between the main terminal 5 and the temperature sensor 9, and between the sense terminals 7 and 8. The temperature sensor 9, sense terminals 7 and 8, and the main terminal 5 are separated from each other by the resin 17 and are insulated from each other. Resin 17 is different from resin 12, for example, and is formed in a separate process. Resin 17 covers the side and bottom surfaces of the temperature sensor 9 and sense terminals 7 and 8.

Here, the main terminal 5 is connected to the first surface electrode 3 via the bonding material 10 even directly below the temperature sensor 9 and the sense terminals 7 and 8. In other words, the main terminal 5 is bonded to the first surface electrode 3 via the bonding material 10 between the temperature sensor 9, the sense terminals 7 and 8 and the semiconductor chip 2 in a direction perpendicular to the main surface of the semiconductor chip 2. Therefore, the provision of the temperature sensor 9 and the sense terminals 7 and 8 reduces the loss between the main terminal 5 and the first surface electrode 3, improving the heat dissipation performance of the chip 21.

Sense terminals 7 and 8 sandwich temperature sensor 9 in the direction along the main surface of semiconductor chip 2. The side surfaces of sense terminals 7 and 8 are connected to the side surfaces of temperature sensor 9, for example, via a bonding material (not shown). The sense terminals 7 and 8 may also be connected to temperature sensor 9 using a structure such as that shown in FIG. 16. That is, as shown in FIG. 16, sense terminals 7 and 8 and temperature sensor 9 may be connected in the vertical direction via bonding material 11. In this case, sense terminals 7 and 8 are thicker than temperature sensor 9 and have protrusions on their side surfaces, with temperature sensor 9 being connected to the upper surfaces of these protrusions.

The height of the top surfaces of the main terminal 5, control terminal 6, temperature sensor 9, and sense terminals 7 and 8 are the same. The thickness of each of the temperature sensor 9, sense terminals 7 and 8 is smaller than the thickness of each of the main terminal 5 and control terminal 6.

The plan view of Figure 17 shows the temperature distribution of chip 31, a semiconductor device. This temperature distribution is based on the results of temperature calculations performed by the inventors when operating chip 31 through thermal simulation. Chip 31 does not have the temperature sensor and sense terminal described in this embodiment and embodiment 1 above. In Figure 17, the outline of control terminal 6 is shown with a dashed line. Furthermore, locations at specified temperatures are connected with solid lines, thereby separating multiple temperature ranges. In Figure 17, central region 1A is a region above 170°C. Region 1B is a region between 160°C and 170°C. Region 1C is a region between 150°C and 160°C. Region 1D is a region below 150°C.

As shown in FIG. 17, when the chip 31 is in operation, the temperature is highest near the center of the chip 31 in a planar view, and the periphery of the chip 31 is cooler than the center. Region 1A is particularly hot, making it the optimal location for detecting temperature changes in the chip 31. Therefore, it is desirable to locate the temperature sensor 9 within region 1A in a planar view. Specifically, in a planar view, the length X1 of one side of the square chip 31 is 5 mm, and the shortest length X2 of region 1A, which is the length passing through the center of the chip 31, is 1.9 mm. In other words, the shortest length X2 of region 1A is 38% of the length X1 of the side of the chip 31. In other words, a range from the center of the chip 31 to 19% of the length of one side of the chip 31 in a planar view overlaps with region 1A. By locating the temperature sensor within this range, more accurate temperature detection is possible. This applies not only to this embodiment but also to the first embodiment described above.

<Effects of this embodiment>
In this embodiment, by arranging the temperature sensor on the outermost surface, the area where the semiconductor chip 2 (first surface electrode 3) and the main terminal 5 are bonded by the bonding material 10 is increased compared to the first embodiment. This allows the thermal resistance of the chip 21 to be reduced compared to the first embodiment.

<Modification>
The temperature sensor and the sense terminal may be disposed on the back surface side of the semiconductor chip 2. Figures 18 and 19 show cross-sectional views of a chip 22 which is a modification of the second embodiment. Figures 18 and 19 are cross-sectional views at locations corresponding to Figures 14 and 15, respectively.

As shown in Figures 18 and 19, in this modified example, the main terminal 5a, bonding material 10, resin 12, temperature sensor 9, and sense terminals 7 and 8 are formed under the back surface of the semiconductor chip 2, rather than on the main surface. The first surface electrode 3 is exposed to the outside of the chip 14 and forms a source pad, while the second surface electrode 3a is exposed to the outside of the chip 14 and forms a gate pad. Like the main terminal 5 shown in Figure 14, the main terminal 5a has a thickness greater than the temperature sensor 9 and sense terminals 7 and 8. The bottom surface of the main terminal 5a is exposed from the resins 12 and 17 and is located at the same height as the bottom surfaces of the sense terminals 7 and 8. The main terminal 5a is electrically connected to the back surface electrode 4 via bonding material 10 and serves as a drain pad. Here, the control terminal 6 (see Figure 14) is not formed.

The temperature sensor 9 is exposed on the exterior of the chip 1. In other words, the main terminal 5a, bonding material 10, resins 12 and 17, temperature sensor 9, and sense terminals 7 and 8 have a configuration similar to that of the main terminal 5, bonding material 10, resins 12 and 17, temperature sensor 9, and sense terminals 7 and 8 shown in Figure 14, but turned upside down.

Even with a structure like this modified example, the same effects as the semiconductor device described using Figures 13 to 16 can be obtained.

The invention made by the inventors has been specifically described above based on the embodiments, but it goes without saying that the present invention is not limited to the above embodiments and can be modified in various ways without departing from the spirit of the invention.

For example, the materials and manufacturing conditions of each part are not limited to those described in the above-mentioned embodiment, and it goes without saying that many variations are possible.

Furthermore, while we have described a chip having a vertical semiconductor element in which current flows between the main surface and back surface of the semiconductor chip, the semiconductor element may also be a horizontal semiconductor element in which current does not flow on the back surface of the semiconductor chip.

1, 14, 15, 21, 22, 31 Chip 2 Semiconductor chip 2a Semiconductor wafer 3 First surface electrode 4 Back surface electrode 5 Main terminal 6 Control terminals 7, 8 Sense terminal 9 Temperature sensor 10, 11 Bonding material 12, 17 Resin 13 Support

Claims (13)

a semiconductor chip having a main surface covered with a first electrode and including a semiconductor element;
a main terminal joined to a portion of the first electrode via a first bonding material having electrical conductivity and electrically connected to the semiconductor element;
a plurality of sense terminals insulated from the main terminals and the first electrodes, spaced apart from the main terminals in a plan view, and thinner than the main terminals;
a temperature sensor having a first surface connected to a surface of each of the plurality of sense terminals on the semiconductor chip side via a second bonding material having conductivity;
a resin that covers a portion of each of the main terminal, the plurality of sense terminals, the first electrode, and the temperature sensor, covers a portion of the first surface of the temperature sensor, and is interposed between the temperature sensor and the first electrode;
and
The semiconductor device, wherein the temperature sensor and the plurality of sense terminals overlap the semiconductor chip in a plan view. 2. The semiconductor device according to claim 1,
a second electrode covering a back surface opposite to the main surface of the semiconductor chip;
a third electrode covering the main surface of the semiconductor chip;
a control terminal joined to the third electrode via a third bonding material having conductivity and electrically connected to the semiconductor element;
The semiconductor device further comprises: 2. The semiconductor device according to claim 1,
the planar shape of the semiconductor device is rectangular,
The semiconductor device, wherein the temperature sensor is provided within a range of a distance that is 19% of the length of one side of the semiconductor device from the center of the semiconductor device in a plan view. 2. The semiconductor device according to claim 1,
The semiconductor device, wherein the temperature sensor is a thermistor or a strain sensor. a semiconductor chip having a main surface covered with a first electrode and including a semiconductor element;
a main terminal joined to a portion of the first electrode via a first bonding material having conductivity, having a recess on a surface opposite to the semiconductor chip side, and electrically connected to the semiconductor element;
a plurality of sense terminals formed in the recess, insulated from the main terminals and the first electrodes, spaced apart from the main terminals in a plan view, and thinner than the main terminals;
a temperature sensor formed in the recess, positioned at the same height as the plurality of sense terminals, and electrically connected to the plurality of sense terminals;
a first resin covering a portion of each of the main terminal and the first electrode;
a second resin interposed within the recess between the main terminal and the temperature sensor and between the main terminal and the temperature sensor and the plurality of sense terminals;
and
the temperature sensor and the plurality of sense terminals overlap with the semiconductor chip in a plan view;
A semiconductor device, wherein a portion of the temperature sensor is exposed to the outside. 6. The semiconductor device according to claim 5,
a second electrode covering a back surface opposite to the main surface of the semiconductor chip;
a third electrode covering the main surface of the semiconductor chip;
a control terminal joined to the third electrode via a second bonding material having conductivity and electrically connected to the semiconductor element;
The semiconductor device further comprises: 6. The semiconductor device according to claim 5,
A semiconductor device, wherein the main terminal is joined to the first electrode via the first joining material between the temperature sensor and the plurality of sense terminals and the semiconductor chip in a direction perpendicular to the main surface of the semiconductor chip. 6. The semiconductor device according to claim 5,
the semiconductor device is a first chip having a rectangular planar shape,
The semiconductor device, wherein the temperature sensor is provided within a range of a distance that is 19% of the length of one side of the semiconductor device from the center of the first chip in a plan view. 6. The semiconductor device according to claim 5,
The semiconductor device, wherein the temperature sensor is a thermistor or a strain sensor. (a) preparing a support, a conductor including a first convex portion formed on the support and a plurality of second convex portions each having a height shorter than that of the first convex portion, a semiconductor substrate including a surface electrode covering a main surface and a semiconductor element electrically connected to the surface electrode, and a temperature sensor;
(b) joining the upper surfaces of the second protrusions to the temperature sensor via a second bonding material having electrical conductivity;
(c) joining the upper surface of the first protrusion and the surface electrode via a first bonding material having electrical conductivity;
(d) after the steps (b) and (c), embedding a resin between the conductor and the semiconductor substrate and between the conductor and the surface electrode;
(e) after the step (d), removing the support to expose a portion of the resin;
and
A method for manufacturing a semiconductor device, wherein a surface of the temperature sensor opposite to the semiconductor substrate side is covered with the second bonding material and the resin. 11. The method for manufacturing a semiconductor device according to claim 10,
the first protrusion constitutes a main terminal,
each of the second protrusions constitutes a sense terminal;
the semiconductor substrate constitutes a semiconductor chip,
The method for manufacturing a semiconductor device, wherein the temperature sensor and the plurality of sense terminals overlap the semiconductor chip in a plan view. 11. The method for manufacturing a semiconductor device according to claim 10,
(f1) after the step (e), further comprising a step of cutting the semiconductor substrate and the resin to obtain a plurality of individualized first chips;
each of the plurality of first chips includes the first protrusion, the plurality of second protrusions, the temperature sensor, the semiconductor substrate, the surface electrode, the first bonding material, and the second bonding material;
The method for manufacturing a semiconductor device, wherein the semiconductor substrate prepared in the step (a) constitutes a semiconductor wafer. 11. The method for manufacturing a semiconductor device according to claim 10,
(f2) after the step (e), further comprising a step of cutting the resin to obtain a plurality of individualized first chips,
In the step (a), the conductor, a semiconductor chip including the semiconductor substrate obtained by dividing a semiconductor wafer, and the temperature sensor are prepared;
A method for manufacturing a semiconductor device, wherein each of the plurality of first chips has the first convex portion, the plurality of second convex portions, the temperature sensor, the semiconductor substrate, the surface electrode, the first bonding material, and the second bonding material.