Semiconductor device

Abstract

To solve such a problem in a manufacturing process of a semiconductor device in which solder on a protective film may scatter and adhere to an electrode.SOLUTION: A semiconductor device comprises: a first electrode which is positioned above a semiconductor substrate; a protective film which includes a part located above the first electrode; a solder part which is positioned with the protective film interposed therebetween in a first direction parallel to the upper surface of the first electrode; a lead frame which is fixed by the solder part and positioned above the protective film; and a second electrode. When the width of the protective film is W1, the length of the protective film is L1, the arithmetic average roughness of the surface of the protective film is Ra, the scattering index is I, and the distance between the protective film and the second electrode is Dmin, the following equation is satisfied. I=((Ra / 4)×L1) / (2×(W1×W1 / π)0.5) Dmin>2.583×I-16599.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a semiconductor device. [Background technology]

[0002] 2. Description of the Related Art Conventionally, in semiconductor devices, structures in which a protective film made of polyimide or the like is provided are known (see, for example, Patent Documents 1 to 4). Patent Document 1: JP 2022-168905 A Patent Document 2: JP 2007-158113 A Patent Document 3: Japanese Patent Application Laid-Open No. 4-155852 Patent Document 4: JP 2018-074068 A Summary of the Invention [Problem to be solved by the invention]

[0003] During the manufacturing process of a semiconductor device, solder on the protective film may scatter and adhere to the electrodes. [Means for solving the problem]

[0004] In order to solve the above problem, a first aspect of the present invention provides a semiconductor device. The semiconductor device may include a semiconductor substrate. Any of the semiconductor devices may include a first electrode disposed above the semiconductor substrate. Any of the semiconductor devices may include a protective film having a portion disposed above the first electrode. Any of the semiconductor devices may include a solder portion disposed in contact with the upper surface of the first electrode, disposed across the protective film in a first direction parallel to the upper surface, and disposed without the protective film in a second direction different from the first direction. Any of the semiconductor devices may include a lead frame fixed by the solder portion and disposed above the protective film. Any of the semiconductor devices may include a second electrode disposed above the semiconductor substrate and outward in the second direction from an end in the second direction of the protective film disposed below the lead frame. In any of the above semiconductor devices, when the width in the first direction of the protective film arranged below the lead frame is W1 (μm), the length of the protective film in the second direction is L1 (μm), the arithmetic mean roughness of the surface of the protective film is Ra (μm), the scattering index is I, and the shortest distance between the end of the protective film and the second electrode is Dmin (μm), the following formula may be satisfied. I=((Ra / 4)×L1) / (2×(W1×W1 / π) 0·5 ) Dmin>2.583×I-16599

[0005] In any one of the above semiconductor devices, the scattering index may satisfy the following formula: 0.8×Dmin>2.583×I-16599

[0006] In any of the above semiconductor devices, the scattering index may be 6000 or less.

[0007] In a second aspect of the present invention, a semiconductor device is provided. The semiconductor device may include a semiconductor substrate. Any of the semiconductor devices may include a first electrode disposed above the semiconductor substrate. Any of the semiconductor devices may include a protective film having a portion disposed above the first electrode. Any of the semiconductor devices may include a solder portion disposed in contact with the upper surface of the first electrode, disposed across the protective film in a first direction parallel to the upper surface, and disposed without the protective film in a second direction different from the first direction. Any of the semiconductor devices may include a lead frame fixed by the solder portion and disposed above the protective film. Any of the semiconductor devices may include a second electrode disposed above the semiconductor substrate and outward in the second direction from an end in the second direction of the protective film disposed below the lead frame. In any of the above semiconductor devices, when the width in the first direction of the protective film arranged below the lead frame is W1 (μm), the length of the protective film in the second direction is L1 (μm), the arithmetic mean roughness of the surface of the protective film is Ra (μm), the scattering index is I, and the maximum distance in the second direction between the end of the protective film and the second electrode is Dmax (μm), the following formula may be satisfied. I=((Ra / 4)×L1) / (2×(W1×W1 / π) 0·5 ) Dmax<2.583×I-16599

[0008] In any one of the above semiconductor devices, the scattering index may satisfy the following formula: 1.2Dmax<2.583×I-16599

[0009] In any of the above semiconductor devices, the protective film arranged below the lead frame has a second portion and a first portion extending in a direction from the second portion toward the second electrode and having a width in the first direction smaller than that of the second portion, and a length L1 of the protective film may be the length of the first portion in the second direction.

[0010] In any of the above semiconductor devices, a space may be formed above the protective film disposed below the lead frame, and the solder portion may be provided between the space and the lead frame.

[0011] In any of the above semiconductor devices, a space may be formed above the protective film arranged below the lead frame, and there may be an area between the space and the lead frame where the solder portion is not provided.

[0012] The above summary of the invention does not list all of the necessary features of the present invention. In addition, subcombinations of these features may also be inventions. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a top view illustrating an example of a semiconductor device 100 according to an embodiment of the present invention. [Diagram 2] 2 is a diagram showing an example of the arrangement of gate runners 48 on a semiconductor substrate 10. FIG. [Diagram 3] 2 is a diagram showing an example of the arrangement of a protective film 150 provided above the upper surface of a semiconductor substrate 10. FIG. [Figure 4] FIG. 4 is a diagram showing an example of a cross section AA in FIG. [Diagram 5] 13 is a diagram showing an example of the arrangement of a protective film 150-1 and solder tunnels 170 when viewed from above. FIG. [Figure 6] 13 is a diagram showing the measurement results of the relationship between the scattering index I and the surplus portion 162. FIG. [Figure 7] 13 is a diagram showing an example of the arrangement of an end portion 175 of a protective film 150-1 and a second electrode 50. FIG. [Figure 8] FIG. 2 is a diagram showing another example of the AA cross section. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the scope of the invention according to the claims. Furthermore, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0015] In this specification, one side in a direction parallel to the depth direction of a semiconductor substrate is referred to as "upper" and the other side as "lower." Of the two main surfaces of a substrate, layer, or other member, one surface is referred to as the upper surface and the other surface is referred to as the lower surface. The directions of "upper" and "lower" are not limited to the direction of gravity or the directions when the semiconductor device is mounted.

[0016] In this specification, technical matters may be explained using orthogonal coordinate axes of X-axis, Y-axis, and Z-axis. The orthogonal coordinate axes merely identify the relative positions of components, and do not limit a specific direction. For example, the Z-axis does not limit the height direction relative to the ground. Note that the +Z-axis direction and the -Z-axis direction are opposite directions. When the Z-axis direction is described without indicating positive or negative, it means a direction parallel to the +Z-axis and -Z-axis. In this specification, the view from the +Z-axis direction may be referred to as a top view.

[0017] In this specification, when the term "same" or "equal" is used, it may include cases where there is an error due to manufacturing variations, etc. The error is, for example, within 10%.

[0018] FIG. 1 is a top view showing an example of a semiconductor device 100 according to an embodiment of the present invention. The semiconductor device 100 includes a semiconductor substrate 10. The semiconductor substrate 10 is a substrate formed of a semiconductor material such as silicon or a compound semiconductor. The semiconductor substrate 10 has an edge 102 in a top view. The semiconductor substrate 10 of this example has two pairs of edges 102 facing each other in a top view. FIG. 1 shows a pair of a first edge 102-1 and a second edge 102-2 facing each other. In FIG. 1, a direction parallel to the first edge 102-1 and the second edge 102-2 is the Y-axis direction, and a direction perpendicular to the first edge 102-1 and the second edge 102-2 is the X-axis direction.

[0019] A semiconductor element such as an IGBT (insulated gate bipolar transistor) is provided on the semiconductor substrate 10. The semiconductor substrate 10 may further include a free wheel diode that is connected in anti-parallel to the IGBT and through which a current flows when the IGBT transitions from an on state to an off state.

[0020] The semiconductor device 100 may be a vertical device in which main electrodes (e.g., an emitter electrode and a collector electrode) are provided on the upper and lower surfaces of the semiconductor substrate 10, respectively, and a main current (e.g., a collector current) flows between the upper and lower surfaces, or a horizontal device in which two main electrodes are provided on the upper surface of the semiconductor substrate 10, and a main current flows in a direction parallel to the upper surface. The semiconductor device 100 may have a structure in which a gate electrode is embedded in a trench formed on the upper surface of the semiconductor substrate 10, or a structure in which a gate electrode is disposed above the upper surface of the semiconductor substrate 10.

[0021] The semiconductor device 100 includes one or more first electrodes 52, one or more second electrodes 50, and a lead frame 130. For example, the first electrode 52 is an emitter electrode of an IGBT. The first electrode 52 is disposed above the upper surface of the semiconductor substrate 10. An interlayer insulating film is provided between the first electrode 52 and the semiconductor substrate 10. The first electrode 52 is connected to the semiconductor substrate 10 via a contact hole provided in the interlayer insulating film.

[0022] The semiconductor device 100 has one or more second electrodes 50. The second electrodes 50 are electrodes other than the first electrode 52 among the electrodes arranged above the upper surface of the semiconductor substrate 10. For example, the second electrodes 50 are a gate pad of an IGBT, a pad for current detection, and a pad for temperature detection. In the example of FIG. 1, the second electrode 50-1 is a gate pad, the second electrode 50-2 is a pad for current detection, and the second electrodes 50-3 and 50-4 are pads for temperature detection. The first electrode 52 and the second electrode 50 are formed of a metal material such as aluminum.

[0023] A gate voltage for switching an IGBT or the like is applied to the second electrode 50-1 in this example. The second electrode 50-1 is connected to an external circuit by wiring such as a wire. The second electrode 50-1 is connected to a gate electrode of the IGBT or the like by wiring such as a gate runner.

[0024] In this example, an element for detecting current is provided on the semiconductor substrate 10 below the second electrode 50-2. The element for detecting current is, for example, an IGBT. The second electrode 50-2 may be an emitter electrode of the IGBT for detecting current. The second electrode 50-2 is connected to an external circuit by wiring such as a wire.

[0025] The second electrodes 50-3 and 50-4 in this example are connected to the temperature detection element 178 by wiring 180 and wiring 182. For example, the temperature detection element 178 is a PN junction diode provided above the semiconductor substrate 10. The wiring 180 and wiring 182 are provided above the semiconductor substrate 10. Since the PN junction diode has temperature characteristics, the temperature of the semiconductor device 100 can be detected by detecting the electrical characteristics of the PN junction diode. One of the second electrodes 50-3 and 50-4 is connected to the cathode of the PN junction diode, and the other is connected to the anode of the PN junction diode. The second electrodes 50-3 and 50-4 are connected to an external circuit by wiring such as a wire.

[0026] The lead frame 130 is a metal wiring that is connected to the first electrode 52. The lead frame 130 may have a plate-like portion that is connected to the first electrode 52. The lead frame 130 and the first electrode 52 are connected by a solder portion.

[0027] 2 is a diagram showing an example of the arrangement of gate runners 48 on a semiconductor substrate 10. The semiconductor substrate 10 of this example is provided with a transistor section 70 and a diode section 80. The transistor section 70 is, for example, an IGBT. The diode section 80 is, for example, a free wheel diode. In FIG. 2, the region where the transistor section 70 is provided is marked with a symbol I, and the region where the diode section 80 is provided is marked with a symbol F. The transistor sections 70 and the diode sections 80 may be arranged alternately along the X-axis direction.

[0028] The gate runner 48 connects the second electrode 50-1 shown in FIG. 1 to the gate electrodes of the respective transistor sections 70. The gate runner 48 may be provided between the edge 102 of the semiconductor substrate 10 and the transistor section 70 and the diode section 80. The gate runner 48 may be provided in a ring shape along the edge 102 of the semiconductor substrate 10. The gate runner 48 may be provided so as to surround the periphery of the first electrode 52 and the second electrode 50. In addition, when the two transistor sections 70 are provided separately in the Y-axis direction as shown in FIG. 2, the gate runner 48 may also be provided between the two transistor sections 70. In the example of FIG. 2, the gate runner 48 is provided along the temperature detection element 178, the wiring 180, and the wiring 182 shown in FIG. 1.

[0029] Gate runner 48 may be a metal wiring made of a metal material such as aluminum, a semiconductor wiring made of polysilicon or the like to which an impurity has been added, or a laminated wiring in which metal wiring and semiconductor wiring are laminated. By providing gate runner 48, the magnitude and application timing of the gate voltage for each transistor portion 70 can be made uniform.

[0030] FIG. 3 is a diagram showing an example of the arrangement of the protective film 150 provided above the upper surface of the semiconductor substrate 10. In FIG. 3, the region where the protective film 150 is arranged is indicated by hatching with oblique lines. The protective film 150 is, for example, a resin such as polyimide. The protective film 150 has a portion provided above the first electrode 52. At least a part of the protective film 150 is provided in a region where the first electrode 52 and the second electrode 50 are not provided. A part of the protective film 150 may be provided on the upper surface of the first electrode 52 or the second electrode 50. The protective film 150 is provided so that at least a part of each of the first electrode 52 and the second electrode 50 is exposed. The first electrode 52 and the second electrode 50 are connected to the lead frame 130 and wiring such as wires at the portions exposed from the protective film 150.

[0031] The protective film 150 in this example is provided so as to cover the upper part of the gate runner 48. A part of the protective film 150 is provided below the lead frame 130. The protective film 150 below the lead frame 130 is referred to as a protective film 150-1. In the example of FIG. 3, a part of the protective film 150 arranged in parallel in the X-axis direction with respect to the second electrode 50-1 is provided below the lead frame 130. A part of the protective film 150-1 may be provided above the temperature detection element 178, the wiring 180, and the wiring 182. The lead frame 130 is provided in a wider range than the protective film 150 in the Y-axis direction (first direction). The lead frame 130 may be provided in a narrower range than the protective film 150 in the X-axis direction.

[0032] A portion of the protective film 150 may be provided so as to surround the region in which the lead frame 130 is provided. With this configuration, it is possible to prevent the solder portion below the lead frame 130 from flowing out to the outside of the lead frame 130.

[0033] Fig. 4 is a diagram showing an example of the AA cross section in Fig. 3. The AA cross section is a YZ plane passing through the lead frame 130 and the protective film 150-1. The AA cross section in Fig. 4 omits the semiconductor substrate 10, the first electrode 52, and the like.

[0034] A solder portion 160 is provided below the lead frame 130. At least a portion of the solder portion 160 is disposed in contact with the upper surface of the first electrode 52. The lead frame 130 is fixed to the first electrode 52 by the solder portion 160. The lead frame 130 is provided above the protective film 150-1.

[0035] 3, the lead frame 130 is provided over a wider area in the Y-axis direction than the protective film 150-1, so that the protective film 150-1 is sandwiched between the solder parts 160 in the Y-axis direction. The solder parts 160 may or may not have a portion provided at the same height as the protective film 150-1. The protective film 150-1 is sandwiched between the solder parts 160 in the Y-axis direction, at least when viewed from above.

[0036] The upper surface of the protective film 150-1 formed of a resin such as polyimide has a relatively low wettability with solder. Therefore, even if the protective film 150-1 is disposed below the lead frame 130, the solder portion 160 may not be formed on the upper surface of the protective film 150-1. In this specification, the space between the protective film 150-1 and the lead frame 130 where the solder portion 160 is not formed is referred to as the solder tunnel 170. The solder tunnel 170 is surrounded by the protective film 150-1 and the solder portion 160 in the YZ cross section. The solder tunnel 170 has an area in the upper part where the solder portion 160 is not provided, and the bottom surface of the lead frame 130 may have a portion exposed to the solder tunnel 170. The width of the protective film 150-1 in the Y-axis direction is W1 (μm). The width of the solder tunnel 170 in the Y-axis direction may also be W1. The width of the solder tunnel 170 may be the width of the space at the position where it contacts the upper surface of the protective film 150-1.

[0037] Fig. 5 is a diagram showing an example of the arrangement of protective film 150-1 and solder tunnels 170 when viewed from above. In this example, protective film 150-1 is provided in the same region as solder tunnels 170. Hatching of protective film 150-1 is omitted in Fig. 5.

[0038] As described in FIG. 3, the lead frame 130 is provided in a narrower range than the protective film 150 in the X-axis direction. Therefore, the protective film 150-1 is not sandwiched between the solder parts 160 in the X-axis direction (second direction). That is, the end 175 of the solder tunnel 170 in the X-axis direction is not covered by the solder part 160 and is open. The end 175 also coincides with the end of the protective film 150-1. The second direction may be the same as the longitudinal direction of the protective film 150-1. The longitudinal direction of the protective film 150-1 is the direction in which the protective film 150-1 extends. The longitudinal direction of the protective film 150-1 may be a direction parallel to the longest side of the end sides of the protective film 150-1. The above-mentioned first direction may be a direction perpendicular to the second direction. As an example, the first direction is the Y-axis direction, and the second direction is the X-axis direction.

[0039] At least one of the second electrodes 50 shown in Fig. 1 and the like is disposed outward in the X-axis direction from the end portion 175. "Outward in the X-axis direction from the end portion 175" refers to a region in the X-axis direction from the end portion 175 to the end portion 102 facing the end portion 175. In the example of Fig. 1, the second electrode 50-1 is disposed between the end portion 175 and the end portion 102-1, and the second electrodes 50-2, 50-3, and 50-4 are disposed between the end portion 175 and the end portion 102-2.

[0040] Since the upper surface of protective film 150-1 has low wettability with solder, solder portion 160 is unlikely to be formed inside solder tunnel 170. However, in the manufacturing process of semiconductor device 100, solder may enter solder tunnel 170. For example, if there is an excess amount of solder in solder portion 160, solder may enter solder tunnel 170. In the example of FIG. 5, excess portion 162 enters solder tunnel 170.

[0041] The manufacturing process of the semiconductor device 100 of this example includes a process of evacuating the space in which the semiconductor device 100 is placed. For example, vacuum reflow may be performed when the lead frame 130 is fixed with the solder portion 160. When vacuum reflow is performed on the semiconductor device 100, the air inside the solder tunnel 170 expands due to reduced pressure and flows to the outside of the solder tunnel 170. If an excess portion 162 exists in the solder tunnel 170, the solder of the excess portion 162 may splash to the outside of the solder tunnel 170. If the splashed solder adheres to the second electrode 50, it becomes difficult to bond wiring such as a wire to the second electrode 50.

[0042] In the semiconductor device 100 of this embodiment, even if solder splashes from inside the solder tunnel 170, the adhesion of solder to the second electrode 50 is suppressed. This facilitates the manufacture of the semiconductor device 100 and improves the reliability of the connection between the second electrode 50 and the wiring. As an example, the structure of the solder tunnel 170 is adjusted to control the distance that solder splashes from the end 175.

[0043] The width in the Y-axis direction of protective film 150-1 disposed below lead frame 130 is W1 (μm), the length in the X-axis direction is L1 (μm), and the arithmetic mean roughness of the surface of protective film 150-1 is Ra (μm). The surface of protective film 150-1 corresponds to the bottom surface of solder tunnel 170.

[0044] The protective film 150-1 of this example has a first portion 151 and a second portion 152. The first portion 151 is provided extending in a direction from the second portion 152 toward the second electrode 50, and has a width in the Y-axis direction smaller than that of the second portion 152. The direction toward the second electrode 50 refers to a direction in which the distance from the second electrode 50 becomes smaller. The second electrode 50 may be disposed on a straight line extending from the first portion 151. The first portion 151 of this example extends in the X-axis direction. That is, the long side of the first portion 151 is parallel to the X-axis direction. As shown in FIG. 5, the second portion 152 may be sandwiched between two first portions 151 in the X-axis direction. The second portion 152 may be provided above the temperature detection element 178. Either of the first portions 151 may be provided extending toward the second electrode 50-2 (for example, a gate pad).

[0045] When protective film 150-1 has first portion 151 and second portion 152, the width W1 and length L1 described above may be the width and length of first portion 151. In this example, second portion 152 has a width in the Y-axis direction W2 and a length in the X-axis direction L2. The energy emitted to the outside by excess portion 162 inside solder tunnel 170 is considered to be the energy of the air inside solder tunnel 170 pushing out excess portion 162. The pressure loss Δh(m) of the air inside solder tunnel 170 is expressed by the Darcy-Weisbach equation below. Δh = (λ × L × v 2 ) / (D×(2g))...Equation (1) where λ is the friction coefficient of the solder tunnel 170, L is the length of the solder tunnel 170 (m), v is the air flow velocity in the solder tunnel 170 (m / s), D is the inner diameter of the solder tunnel 170 (m), and g is the gravitational acceleration (m / s 2 ).

[0046] As shown in formula (1), the energy given to the surplus portion 162 depends on λ, L, and D. In this specification, the scattering index I (μm) of the following formula is used as an index indicating the energy given to the surplus portion 162. I=λ×L / D...Equation (2)

[0047] The protective film 150-1 and the solder section 160 are exposed on the inner wall of the solder tunnel 170. The friction coefficient of the protective film 150-1 made of resin or the like is sufficiently larger than the friction coefficient of the solder section 160 and the lead frame 130 made of metal, so the friction coefficient of the solder tunnel 170 can be approximated using the friction coefficient of the protective film 150-1. In this specification, the arithmetic mean roughness Ra (μm) of the surface of the protective film 150-1 is used as a coefficient indicating the friction coefficient of the protective film 150-1. The smaller the arithmetic mean roughness Ra, the smoother the surface of the protective film 150-1 is, and the smaller the friction coefficient is. The protective film 150-1 is exposed only on the bottom surface of the solder tunnel 170, and is not exposed on the two side surfaces and the top surface, so Ra / 4 is used as the friction coefficient λ of the solder tunnel 170. Moreover, the length L1 of the protective film 150-1 disposed below the lead frame 130 corresponds to the length L of the solder tunnel 170.

[0048] It is considered that the height of the solder tunnel 170 depends on the width W1 of the protective film 150-1. That is, the larger the width W1, the higher the solder tunnel 170. In this specification, the following formula is used to express the inner diameter D of the solder tunnel 170. D = 2 × (W1 × W1 / π) 0·5 ...Equation (3)

[0049] λ=Ra / 4, L=L1, D=(W1×W1 / π) 0·5 Substituting this into equation (2), the scattering index I is given by the following equation: I=((Ra / 4)×L1) / (2×(W1×W1 / π) 0·5 )...Equation (4) The scattering index I indicates the energy given to the excess portion 162. In other words, the scattering index I indicates the flying distance of the ejected excess portion 162 from the end 175 of the solder tunnel 170. The larger the scattering index I, the greater the energy given to the excess portion 162, and therefore the greater the flying distance.

[0050] 6 is a diagram showing the measurement results of the relationship between the scattering index I and the excess part 162. In this example, the solder used for the solder part 160 is a Sn-Cu solder, and has a specific gravity of 7.3 g / cm3 The width W2 of second portion 152 is three times or more the width W1. The length L2 of second portion 152 is 0.7 times or more and 1.3 times or less the length L1. Since the width W2 of second portion 152 is sufficiently larger than W1, the energy given to surplus portion 162 can be approximated by the energy of first portion 151.

[0051] As shown in Fig. 6, it can be seen that the larger the scattering index I, the greater the flying distance of the surplus portion 162. Therefore, the flying distance of the surplus portion 162 can be estimated from the scattering index I. The relationship between the scattering index I and the flying distance FD (μm) shown in Fig. 6 is approximated by a straight line 184, resulting in the following equation. FD=2.583×I-16599 Equation (5)

[0052] 7 is a diagram showing an example of the arrangement of the end 175 of the protective film 150-1 and the second electrode 50. As described above, the end 175 of the protective film 150-1 is also the end of the solder tunnel 170. The shortest distance between the end 175 of the protective film 150-1 and the second electrode 50 is defined as Dmin (μm). If the flying distance FD shown in formula (5) is smaller than the shortest distance Dmin, it is possible to prevent the excess portion 162 from flying to the second electrode 50. In other words, it is sufficient that the scattering index I satisfies the following formula. Dmin>2.583×I-16599...Equation (6) The scattering index I may satisfy the following formula: 0.8×Dmin>2.583×I-16599...Equation (7) In this case, scattering of the excess portion 162 onto the second electrode 50 can be further suppressed.

[0053] The scattering index I may be equal to or less than 6000. As shown in Fig. 6, when the scattering index I is equal to or less than 6000, the scattering distance of the surplus portion 162 becomes 0. This makes it possible to further prevent the surplus portion 162 from scattering onto the second electrode 50.

[0054] The larger the width W1 of the protective film 150-1, the smaller the scattering index I can be. The width W1 may be 0.15 mm or more, 0.2 mm or more, 0.3 mm or more, 0.5 mm or more, or 0.7 mm or more. The width W1 may be 0.5 times or more, or 0.75 times or more, of the width W2. The width W1 may be larger than the width W2. The width in the Y-axis direction at the end 175 may be larger than the width in the Y-axis direction of any other part. The width of the protective film 150-1 may increase in a tapered manner or in a stepwise manner toward the end 175. The width of the end 175 in this case may be smaller than, the same as, or larger than the width W2.

[0055] The shorter the length L1 of the protective film 150-1, the smaller the scattering index I. The length L1 may be 3 mm or less, 2 mm or less, or 1.5 mm or less. The length L1 may be 1.3 times the length L2 or less, may be smaller than the length L2, or may be 0.5 times the length L2 or less.

[0056] The smaller the arithmetic mean roughness Ra of the surface of protective film 150-1, the smaller the scattering index I. The arithmetic mean roughness Ra may be 2500 μm or less, 2000 μm or less, 1500 μm or less, or 1000 μm or less.

[0057] The maximum distance between the end 175 of the protective film 150-1 and the second electrode 50 is Dmax (μm). The maximum distance Dmax may be the maximum distance in the X-axis direction in which the protective film 150-1 extends, or may be the maximum distance in all directions. When the flying distance FD shown in formula (5) is greater than the maximum distance Dmax, the excess portion 162 will fly over the second electrode 50 and scatter, so that it is possible to prevent the excess portion 162 from adhering to the second electrode 50. In other words, it is sufficient that the scattering index I satisfies the following formula. Dmax<2.583×I-16599...Formula (8) The scattering index I may satisfy the following formula: 1.2×Dmax<2.583×I-16599...Equation (9) In this case, scattering of the excess portion 162 onto the second electrode 50 can be further suppressed.

[0058] The smaller the width W1 of the protective film 150-1, the larger the scattering index I can be. The width W1 may be 0.1 mm or less, 0.075 mm or less, or 0.05 mm or less. The width W1 may be 0.5 times or less, 0.3 times or less, or 0.1 times or less of the width W2. In addition, the width of the protective film 150-1 may decrease in a tapered manner or in a stepwise manner toward the end portion 175.

[0059] The longer the length L1 of the protective film 150-1, the higher the scattering index I. The length L1 may be 5 mm or more, 6 mm or more, or 7 mm or more. The length L1 may be 1.5 times or more the length L2, or 1.7 times or more the length L2.

[0060] The larger the arithmetic mean roughness Ra of the surface of the protective film 150-1, the larger the scattering index I. The arithmetic mean roughness Ra may be 3000 μm or more, 3500 μm or more, 4000 μm or more, or 5000 μm or more.

[0061] When the protective film 150-1 has a plurality of first portions 151, at least one of the first portions 151 may satisfy any of the conditions of the scattering index I described above. As an example, among the plurality of first portions 151, the first portion 151 whose end portion 175 is closest to the gate pad (e.g., the second electrode 50-2) may satisfy the conditions of the scattering index I described above. In another example, all of the first portions 151 may satisfy any of the conditions of the scattering index I described above. Any of the first portions 151 may satisfy the conditions of formula (6) or formula (7), and any of the other first portions 151 may satisfy the conditions of formula (8) or formula (9).

[0062] Fig. 8 is a diagram showing another example of the AA cross section. In the example of Fig. 4, a space (solder tunnel 170) is formed above the protective film 150-1, and the solder portion 160 is provided between the space and the lead frame 130. In other words, the lead frame 130 is not exposed to the solder tunnel 170. In the example of Fig. 8, there is a region where the solder portion 160 is not provided between the space (solder tunnel 170) above the protective film 150-1 and the lead frame 130. In other words, the bottom surface of the lead frame 130 is exposed to the solder tunnel 170.

[0063] The arithmetic mean roughness of the bottom surface of the lead frame 130 exposed to the solder tunnel 170 may be smaller than the arithmetic mean roughness Ra of the protective film 150-1. In this case, by exposing the lead frame 130 to the solder tunnel 170, the friction coefficient on the inner wall of the solder tunnel 170 can be reduced, and the flying distance of the excess portion 162 can be reduced compared to the flying distance FD shown in formula (5). This makes it possible to prevent the excess portion 162 from reaching the second electrode 50. The area of ​​the bottom surface of the lead frame 130 exposed to the solder tunnel 170 may be half or more of the area of ​​the top surface of the protective film 150-1, may be 0.75 times or more, may be 1 time, or may be greater than 1 time.

[0064] The bottom surface of the lead frame 130 exposed to the solder tunnel 170 may be formed with irregularities to make the arithmetic mean roughness of the bottom surface of the lead frame 130 larger than the arithmetic mean roughness Ra of the protective film 150-1. By increasing the calculated mean roughness of the bottom surface of the lead frame 130, the jump distance of the excess portion 162 can be increased. This makes it easier for the excess portion 162 to jump over the second electrode 50. The arithmetic mean roughness of the bottom surface of the lead frame 130 may be two or more times, five or more times, or ten or more times the arithmetic mean roughness Ra of the protective film 150-1. The area of ​​the bottom surface of the lead frame 130 exposed to the solder tunnel 170 may be half or more of the area of ​​the top surface of the protective film 150-1, 0.75 or more times, 1 time, or more than 1 time.

[0065] Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is clear to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the description of the claims that such modifications and improvements can also be included in the technical scope of the present invention. [Explanation of symbols]

[0066] REFERENCE SIGNS LIST 10 semiconductor substrate, 48 gate runner, 50 second electrode, 52 first electrode, 70 transistor portion, 80 diode portion, 100 semiconductor device, 102 edge, 130 lead frame, 150 protective film, 151 first portion, 152 second portion, 160 solder portion, 162 excess portion, 170 solder tunnel, 175 edge, 178 temperature detection element, 180, 182 wiring, 184 straight line

Claims

1. A semiconductor substrate; A first electrode disposed above the semiconductor substrate; a protective film having a portion provided above the first electrode; a solder portion disposed in contact with an upper surface of the first electrode, disposed across the protective film in a first direction parallel to the upper surface, and disposed without the protective film in a second direction different from the first direction; a lead frame fixed by the solder portion and disposed above the protective film; a second electrode disposed above the semiconductor substrate and on the outer side in the second direction of an end portion in the second direction of the protective film disposed below the lead frame; Equipped with When the width of the protective film disposed under the lead frame in the first direction is W1 (μm), the length of the protective film in the second direction is L1 (μm), the arithmetic mean roughness of the surface of the protective film is Ra (μm), the scattering index is I, and the shortest distance between the end of the protective film and the second electrode is Dmin (μm), the following formula is satisfied: I = ((R / 4)×L1) / (2×(W1×W1 / π) ０・５ ) Dmin>2.583×I-16599 Semiconductor device.

2. The scattering index satisfies the following formula: 0.8 x Dmin > 2.583 x I - 16599 The semiconductor device according to claim 1 .

3. The scattering index is 6000 or less. The semiconductor device according to claim 1 .

4. A semiconductor substrate; A first electrode disposed above the semiconductor substrate; a protective film having a portion provided above the first electrode; a solder portion disposed in contact with an upper surface of the first electrode, disposed across the protective film in a first direction parallel to the upper surface, and disposed without the protective film in a second direction different from the first direction; a lead frame fixed by the solder portion and disposed above the protective film; a second electrode disposed above the semiconductor substrate and on the outer side in the second direction of an end portion in the second direction of the protective film disposed below the lead frame; Equipped with When the width of the protective film disposed under the lead frame in the first direction is W1 (μm), the length of the protective film in the second direction is L1 (μm), the arithmetic mean roughness of the surface of the protective film is Ra (μm), the scattering index is I, and the maximum distance between the end of the protective film and the second electrode is Dmax (μm), the following formula is satisfied: I = ((R / 4)×L1) / (2×(W1×W1 / π) ０・５ ) Dmax<2.583×I-16599 Semiconductor device.

5. The scattering index satisfies the following formula: 1.2Dmax<2.583×I-16599 The semiconductor device according to claim 4.

6. The protective film disposed under the lead frame is A second part; and a first portion extending in a direction from the second portion toward the second electrode and having a width in the first direction smaller than that of the second portion; having The length L1 of the protective film is the length of the first portion in the second direction. The semiconductor device according to claim 1 .

7. A space is formed above the protective film disposed below the lead frame, and the solder portion is provided between the space and the lead frame. The semiconductor device according to claim 1 .

8. A space is formed above the protective film disposed below the lead frame, and a region in which the solder portion is not provided is provided between the space and the lead frame. The semiconductor device according to claim 1 .

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