Semiconductor device

Abstract

The invention provides a semiconductor device which solves the problem that in the manufacturing process of the semiconductor device, solder on a protective film sometimes scatters and adheres to an electrode. The semiconductor device includes: a first electrode disposed above a semiconductor substrate; a protective film having a portion provided above the first electrode; a solder portion disposed so as to sandwich the protective film in a first direction parallel to the upper surface of the first electrode; a lead frame fixed by the solder portion and disposed above the protective film; and a second electrode which satisfies the following expressions: I = ((Ra / 4) * L1) / (2 * (W1 * W1 / pi) 0.5) and Dmin > 2.583 * I-16599, where W1 is the width of the protective film, L1 is the length of the protective film, Ra is the arithmetic average roughness of the surface of the protective film, I is the scatter index, and Dmin is the distance between the protective film and the second electrode.

Description

Technical Field

[0001] The present invention relates to semiconductor devices. Background Art

[0002] Conventionally, there is known a structure in which a protective film such as polyimide is provided in a semiconductor device (for example, refer to Patent Documents 1 to 4).

[0003] Patent Document 1: Japanese Patent Application Publication No. 2022-168905

[0004] Patent Document 2: Japanese Patent Application Publication No. 2007-158113

[0005] Patent Document 3: Japanese Patent Application Laid-Open No. 4-155852

[0006] Patent Document 4: Japanese Patent Application Publication No. 2018-074068 Summary of the invention

[0007] Technical issues

[0008] In the process of manufacturing a semiconductor device, solder on a protective film may scatter and adhere to an electrode.

[0009] Technical Solution

[0010] In order to solve the above-mentioned problems, in a first mode 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, and disposed with the protective film sandwiched in a first direction parallel to the upper surface, and disposed without the protective film sandwiched 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 at a position further outward in the second direction than an end portion of the protective film disposed below the lead frame in the second direction. In any of the above-mentioned semiconductor devices, when the width of the protective film arranged below the lead frame in the first direction is set to W1 (μm), the length of the protective film in the second direction is set to L1 (μm), the arithmetic mean roughness of the surface of the protective film is set to Ra (μm), the scattering index is set to I, and the shortest distance between the end of the protective film and the second electrode is set to Dmin (μm), the following formula can be satisfied:

[0011] I=((Ra / 4)×L1) / (2×(W1×W1 / π) 0.5 ),

[0012] Dmin>2.583×I-16599.

[0013] In any of the above semiconductor devices, the scattering index may satisfy the following formula:

[0014] 0.8×Dmin>2.583×I-16599.

[0015] In any of the above semiconductor devices, the scattering index may be 6000 or less.

[0016] 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, and disposed with the protective film sandwiched in a first direction parallel to the upper surface, and disposed without the protective film sandwiched 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 at a position further outward in the second direction than an end portion of the protective film disposed below the lead frame in the second direction. In any of the above-mentioned semiconductor devices, when the width of the protective film arranged below the lead frame in the first direction is set to W1 (μm), the length of the protective film in the second direction is set to L1 (μm), the arithmetic mean roughness of the surface of the protective film is set to Ra (μm), the scattering index is set to I, and the maximum distance between the end of the protective film in the second direction and the second electrode is set to Dmax (μm), the following formula can be satisfied:

[0017] I=((Ra / 4)×L1) / (2×(W1×W1 / π) 0.5 ),

[0018] Dmax<2.583×I-16599.

[0019] In any of the above semiconductor devices, the scattering index may satisfy the following formula:

[0020] 1.2Dmax<2.583×I-16599.

[0021] In any of the above-mentioned semiconductor devices, the protective film arranged below the lead frame may have a second part and a first part, the first part is extended from the second part in a direction toward the second electrode, and the width of the first part in the first direction is smaller than the width of the second part in the first direction, and the length L1 of the protective film is the length of the first part in the second direction.

[0022] In any of the above-described 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.

[0023] In any of the semiconductor devices described above, a space may be formed above the protective film disposed below the lead frame, and a region where the solder portion is not provided may exist between the space and the lead frame.

[0024] The above invention summary does not list all the essential features of the present invention. In addition, sub-combinations of these feature groups can also become inventions. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 1 is a plan view showing an example of a semiconductor device 100 according to an embodiment of the present invention.

[0026] Figure 2 1 is a diagram showing an example of arrangement of the gate flow channel 48 on the semiconductor substrate 10 .

[0027] Figure 3 1 is a diagram showing an example of arrangement of a protective film 150 provided above the upper surface of the semiconductor substrate 10 .

[0028] Figure 4 It is shown Figure 3 A diagram showing an example of the AA section in FIG.

[0029] Figure 5 1 is a diagram showing an example of arrangement of the protective film 150 - 1 and the solder channel 170 in a plan view.

[0030] Figure 6 1 is a diagram showing the measurement results of the relationship between the scattering index I and the remaining portion 162 .

[0031] Figure 7 1 is a diagram showing an example of arrangement of the end portion 175 of the protective film 150 - 1 and the second electrode 50 .

[0032] Figure 8 This is a diagram showing another example of the AA cross section.

[0033] Explanation of symbols

[0034] 10…semiconductor substrate, 48…gate channel, 50…second electrode, 52…first electrode, 70…transistor portion, 80…diode portion, 100…semiconductor device, 102…end edge, 130…lead frame, 150…protective film, 151…first portion, 152…second portion, 160…solder portion, 162…remaining portion, 170…solder channel, 175…end portion, 178…temperature detection element, 180, 182…wiring, 184…straight line. DETAILED DESCRIPTION

[0035] Hereinafter, the present invention will be described by way of the embodiments of the invention, but the following embodiments do not limit the invention involved in the claims. In addition, all combinations of features described in the embodiments are not necessarily essential to the technical means of the invention.

[0036] In this specification, one side in a direction parallel to the depth direction of the semiconductor substrate is referred to as "upper", and the other side is referred to as "lower". One of the two main surfaces of a substrate, layer, or other component is referred to as an upper surface, and the other is referred to as a lower surface. The directions of "upper" and "lower" are not limited to the direction of gravity or the direction when the semiconductor device is actually installed.

[0037] In this specification, sometimes the orthogonal coordinate axes of the X-axis, Y-axis and Z-axis are used to explain technical matters. The orthogonal coordinate axes are only used to determine the relative positions of the components and do not limit specific directions. For example, the Z-axis does not limit the height direction relative to the ground. It should be noted that the +Z-axis direction and the -Z-axis direction are opposite directions to each other. When the positive and negative are not recorded but the Z-axis direction is recorded, it means the direction parallel to the +Z-axis and the -Z-axis. In addition, in this specification, sometimes the observation from the +Z-axis direction is referred to as a top view.

[0038] In this specification, when it is said that they are "same" or "equal", it may include the case where there is an error due to manufacturing variation, etc. The error is within 10%, for example.

[0039] Figure 1 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 when viewed from above. The semiconductor substrate 10 of this example has two sets of edge 102 that are opposite to each other when viewed from above. Figure 1 In FIG. 1 , a first end side 102-1 and a second end side 102-2 that are opposite to each other are shown. Figure 1In the figure, a direction parallel to the first end side 102-1 and the second end side 102-2 is set as a Y-axis direction, and a direction perpendicular to the first end side 102-1 and the second end side 102-2 is set as an X-axis direction.

[0040] A semiconductor element such as an IGBT (insulated gate bipolar transistor) is provided on the semiconductor substrate 10. A flyback diode which is connected in reverse parallel to the IGBT and allows current to flow when the IGBT changes from an on state to an off state may be further provided on the semiconductor substrate 10.

[0041] 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 surface and the lower surface of the semiconductor substrate 10, respectively, and a main current (e.g., a collector current) flows between the upper surface and the lower surface, or may be 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 buried in a trench formed on the upper surface of the semiconductor substrate 10, or may have a structure in which a gate electrode is arranged above the upper surface of the semiconductor substrate 10.

[0042] 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 arranged 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.

[0043] The semiconductor device 100 has one or more second electrodes 50. The second electrode 50 is an electrode other than the first electrode 52 among the electrodes arranged above the upper surface of the semiconductor substrate 10. For example, the second electrode 50 is a gate pad of an IGBT, a pad for current detection, and a pad for temperature detection. Figure 1 In the example of FIG. 5 , the second electrode 50 - 1 is a gate pad, the second electrode 50 - 2 is a current detection pad, and the second electrode 50 - 3 and the second electrode 50 - 4 are temperature detection pads. The first electrode 52 and the second electrode 50 are formed of a metal material such as aluminum.

[0044] A gate voltage for switching the IGBT or the like is applied to the second electrode 50-1 of this example. The second electrode 50-1 is connected to an external circuit via wiring such as a wire. The second electrode 50-1 is connected to a gate electrode of the IGBT or the like via wiring such as a gate channel.

[0045] In this example, a current detection element is provided on the semiconductor substrate 10 below the second electrode 50-2. The current detection element is, for example, an IGBT. The second electrode 50-2 may be an emitter electrode of the IGBT for current detection. The second electrode 50-2 is connected to an external circuit via wiring such as a wire.

[0046] The second electrode 50-3 and the second electrode 50-4 of this example are connected to the temperature detection element 178 through the wiring 180 and the wiring 182. For example, the temperature detection element 178 is a PN junction diode disposed above the semiconductor substrate 10. The wiring 180 and the wiring 182 are disposed, for example, above the semiconductor substrate 10. Since the PN junction diode has a temperature characteristic, the temperature of the semiconductor device 100 can be detected by detecting the electrical characteristics of the PN junction diode. One of the second electrode 50-3 and the second electrode 50-4 is connected to the cathode of the PN junction diode, and the other electrode is connected to the anode of the PN junction diode. The second electrode 50-3 and the second electrode 50-4 are connected to an external circuit through wiring such as a wire.

[0047] The lead frame 130 is a metal wiring connected to the first electrode 52. The lead frame 130 may have a plate-shaped portion connected to the first electrode 52. The lead frame 130 and the first electrode 52 are connected through a solder portion.

[0048] Figure 2 1 is a diagram showing an example of the configuration of the gate channel 48 on the semiconductor substrate 10. The semiconductor substrate 10 of this example is provided with a transistor portion 70 and a diode portion 80. The transistor portion 70 is, for example, an IGBT. The diode portion 80 is, for example, a freewheeling diode. Figure 2 In FIG. 1 , a region where the transistor portion 70 is provided is denoted by a symbol I, and a region where the diode portion 80 is provided is denoted by a symbol F. The transistor portion 70 and the diode portion 80 may be alternately arranged along the X-axis direction.

[0049] The gate flow channel 48 will Figure 1 The second electrode 50-1 shown is connected to the gate electrode of each transistor unit 70. The gate channel 48 can be provided between the end 102 of the semiconductor substrate 10 and the transistor unit 70 and the diode unit 80. The gate channel 48 can be provided in a ring shape along the end 102 of the semiconductor substrate 10. The gate channel 48 can be provided in a manner surrounding the first electrode 52 and the second electrode 50. In addition, as shown in FIG. Figure 2 As shown in FIG. 1 , when two transistor sections 70 are provided separately in the Y-axis direction, a gate channel 48 may be provided between the two transistor sections 70. Figure 2 In the example, along Figure 1 The temperature detection element 178 , the wiring 180 , and the wiring 182 shown are provided with the gate runner 48 .

[0050] The gate channel 48 may be a metal wiring formed of a metal material such as aluminum, a semiconductor wiring formed of polysilicon with impurities, or a stacked wiring formed by stacking metal wiring and semiconductor wiring. By providing the gate channel 48, the magnitude and application timing of the gate voltage for each transistor unit 70 can be made uniform.

[0051] Figure 3 1 is a diagram showing an example of the configuration of the protective film 150 provided above the upper surface of the semiconductor substrate 10. Figure 3 , the region where the protective film 150 is arranged is indicated by oblique hatching. The protective film 150 is, for example, a resin such as polyimide. The protective film 150 has a portion arranged at a position higher than the first electrode 52. At least a portion of the protective film 150 is arranged in a region where the first electrode 52 and the second electrode 50 are not arranged. A portion of the protective film 150 may be arranged on the upper surface of the first electrode 52 or the second electrode 50. The protective film 150 is arranged in a manner that at least a portion of each of the first electrode 52 and the second electrode 50 is exposed. Each of the first electrode 52 and the second electrode 50 is connected to wiring such as the lead frame 130 and a wire in a portion exposed from the protective film 150.

[0052] The protective film 150 of this example is provided so as to cover the upper part of the gate flow channel 48. A part of the protective film 150 is provided under the lead frame 130. The protective film 150 under the lead frame 130 is referred to as a protective film 150-1. Figure 3 In the example of , a portion of the protective film 150 arranged in the X-axis direction with the second electrode 50-1 is provided below the lead frame 130. A portion 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 range wider than the protective film 150 in the Y-axis direction (first direction). The lead frame 130 may be provided in a range narrower than the protective film 150 in the X-axis direction.

[0053] A portion of the protective film 150 may be provided so as to surround the region where the lead frame 130 is provided. With such a configuration, it is possible to suppress the solder portion below the lead frame 130 from flowing out to the outside of the lead frame 130 .

[0054] Figure 4 It is shown Figure 3 AA cross section is a diagram of an example of the AA cross section in FIG. The AA cross section is a YZ plane passing through the lead frame 130 and the protective film 150 - 1 . Figure 4 The semiconductor substrate 10, the first electrode 52, and the like are omitted in the AA cross section in FIG.

[0055] 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.

[0056] like Figure 3 As shown in the figure, since the lead frame 130 is provided in a wider range than the protective film 150-1 in the Y-axis direction, the protective film 150-1 is sandwiched by the solder portion 160 in the Y-axis direction. The solder portion 160 may have a portion provided at the same height as the protective film 150-1, or may not have a portion provided at the same height as the protective film 150-1. The protective film 150-1 is sandwiched by the solder portion 160 in the Y-axis direction at least in a plan view.

[0057] The wettability of the solder on the upper surface of the protective film 150-1 formed of a resin such as polyimide is relatively low. Therefore, even if the protective film 150-1 is arranged below the lead frame 130, there is a situation where the solder portion 160 is not 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 channel 170. The solder channel 170 is surrounded by the protective film 150-1 and the solder portion 160 in the YZ cross section. The solder channel 170 may also have an area where the solder portion 160 is not provided at the upper part, and there is a portion where the bottom surface of the lead frame 130 is exposed in the solder channel 170. The width of the protective film 150-1 in the Y-axis direction is set to W1 (μm). The width of the solder channel 170 in the Y-axis direction may also be W1. The width of the solder channel 170 may be the width of a space at a position in contact with the upper surface of the protective film 150 - 1 .

[0058] Figure 5 1 is a diagram showing an example of the arrangement of the protective film 150-1 and the solder channel 170 in a plan view. In this example, the protective film 150-1 is provided in the same region as the solder channel 170. Figure 5 The hatching of the protection film 150 - 1 is omitted.

[0059] As in Figure 3As described in the figure, the lead frame 130 is arranged in a range narrower than the protective film 150 in the X-axis direction. Therefore, the protective film 150-1 is not clamped by the solder portion 160 in the X-axis direction (the second direction). That is, the end 175 of the solder channel 170 in the X-axis direction is not covered by the solder portion 160 and becomes an opening. The end 175 is also consistent with the end of the protective film 150-1. The second direction can be the same as the long side direction of the protective film 150-1. The long side direction of the protective film 150-1 refers to the direction in which the protective film 150-1 extends. The long side direction of the protective film 150-1 can be a direction parallel to the longest side of the end side of the protective film 150-1. The above-mentioned first direction can 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.

[0060] Figure 1 At least one of the second electrodes 50 shown in the figure is arranged at a position further outward than the end 175 in the X-axis direction. Further outward than the end 175 in the X-axis direction refers to a region from the end 175 to the end side 102 opposite to the end 175 in the X-axis direction. Figure 1 In the example, the second electrode 50 - 1 is arranged between the end portion 175 and the end side 102 - 1 , and the second electrodes 50 - 2 , 50 - 3 , and 50 - 4 are arranged between the end portion 175 and the end side 102 - 2 .

[0061] Since the upper surface of the protective film 150-1 has low wettability to solder, it is difficult to form the solder portion 160 inside the solder channel 170. However, during the manufacturing process of the semiconductor device 100, solder may enter the solder channel 170. For example, when the amount of solder in the solder portion 160 is excessive, solder may enter the solder channel 170. Figure 5 In the example shown in FIG. 1 , the remaining portion 162 enters the solder channel 170 .

[0062] In the manufacturing process of the semiconductor device 100 of this example, there is a process of evacuating the space where the semiconductor device 100 is arranged. For example, when the lead frame 130 is fixed by the solder portion 160, vacuum reflow soldering is sometimes performed. If the semiconductor device 100 is subjected to vacuum reflow soldering, the air inside the solder channel 170 expands due to the decompression and flows to the outside of the solder channel 170. If there is a surplus portion 162 in the solder channel 170, the solder of the surplus portion 162 may scatter to the outside of the solder channel 170. If the scattered solder adheres to the second electrode 50, it is difficult to bond the wiring such as the wire to the second electrode 50.

[0063] In the semiconductor device 100 of this example, even when the solder is scattered from the inside of the solder channel 170, the solder is prevented from adhering to the second electrode 50. Thus, the manufacturing of the semiconductor device 100 can be facilitated, and the reliability of the connection between the second electrode 50 and the wiring can be improved. As an example, by adjusting the structure of the solder channel 170, the flight distance of the solder scattered from the end 175 can be controlled.

[0064] The width of the protective film 150 - 1 disposed below the lead frame 130 in the Y-axis direction is W1 (μm), the length in the X-axis direction is L1 (μm), and the arithmetic mean roughness of the surface of the protective film 150 - 1 is Ra (μm). The surface of the protective film 150 - 1 corresponds to the bottom surface of the solder channel 170 .

[0065] The protective film 150-1 of this example has a first portion 151 and a second portion 152. The first portion 151 is a portion extending from the second portion 152 in the direction toward the second electrode 50, and has a width in the Y-axis direction that is smaller than the width of the second portion 152 in the Y-axis direction. 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 also be arranged on a straight line extending 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 Figure 5 As shown, the second portion 152 may be sandwiched by two first portions 151 in the X-axis direction. The second portion 152 may be disposed above the temperature detection element 178. Any one of the first portions 151 may be disposed to extend toward the second electrode 50-2 (eg, a gate pad).

[0066] In the case where the protective film 150-1 has a first portion 151 and a second portion 152, the width W1 and the length L1 described above can use the width and length of the first portion 151. In this example, the width of the second portion 152 in the Y-axis direction is set to W2, and the length in the X-axis direction is set to L2. The energy emitted to the outside by the remaining portion 162 inside the solder channel 170 can be considered as the energy of the air inside the solder channel 170 pushing the remaining portion 162 out. The pressure loss Δh (m) of the air inside the solder channel 170 is expressed by the following Darcy-Weisbach equation:

[0067] Δh=(λ×L×v 2 ) / (D×(2g))…Formula (1).

[0068] Wherein, λ is the friction coefficient of the solder channel 170, L is the length of the solder channel 170 (m), v is the flow rate of the air in the solder channel 170 (m / s), D is the inner diameter of the solder channel 170 (m), and g is the acceleration due to gravity (m / s2 ).

[0069] As shown in formula (1), the energy applied to the remaining 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 representing the energy applied to the remaining portion 162:

[0070] I = λ×L / D…Formula (2).

[0071] The protective film 150-1 and the solder portion 160 are exposed on the inner wall of the solder channel 170. Since the friction coefficient of the protective film 150-1 formed of resin or the like is sufficiently greater than the friction coefficient of the solder portion 160 and the lead frame 130 formed of metal, the friction coefficient of the solder channel 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 representing the friction coefficient of the protective film 150-1. Since the smaller the arithmetic mean roughness Ra, the smoother the surface of the protective film 150-1, the smaller the friction coefficient. Since the protective film 150-1 is exposed only on the bottom surface of the solder channel 170, and not on the two side surfaces and the upper surface, Ra / 4 is used as the friction coefficient λ of the solder channel 170. In addition, the length L1 of the protective film 150-1 disposed below the lead frame 130 is equivalent to the length L of the solder channel 170.

[0072] It can be considered that the height of the solder channel 170 depends on the width W1 of the protective film 150-1. That is, the larger the width W1 is, the higher the solder channel 170 is. In this specification, the following formula is used as a formula representing the inner diameter D of the solder channel 170:

[0073] D=2×(W1×W1 / π) 0.5 …Formula (3).

[0074] If

[0075] λ=Ra / 4, L=L1, D=(W1×W1 / π) 0.5

[0076] Substituting into formula (2), the scattering index I becomes as follows:

[0077] I=((Ra / 4)×L1) / (2×(W1×W1 / π) 0.5 )...Formula (4).

[0078] The scattering index I indicates the energy given to the remaining portion 162. That is, the scattering index I indicates the flying distance of the ejected remaining portion 162 from the end 175 of the solder channel 170. Since the larger the scattering index I, the greater the energy given to the remaining portion 162, the greater the flying distance.

[0079] Figure 6 1 is a graph showing the measurement results of the relationship between the scattering index I and the remaining portion 162. In this example, the solder used for the solder portion 160 is a Sn-Cu solder having a specific gravity of 7.3 g / cm 3 In addition, the width W2 of the second portion 152 is more than 3 times the width W1. The length L2 of the second portion 152 is more than 0.7 times and less than 1.3 times the length L1. Since the width W2 of the second portion 152 is sufficiently larger than W1, the energy given to the remaining portion 162 can be approximated by the energy obtained based on the first portion 151.

[0080] It can be known that Figure 6 As shown in FIG. 1 , the greater the scattering index I, the greater the flying distance of the remaining portion 162. Therefore, the flying distance of the remaining portion 162 can be estimated based on the scattering index I. Figure 6 The relationship between the scattering index I and the flight distance FD (μm) shown in the figure is approximated as follows:

[0081] FD=2.583×I-16599…Equation (5).

[0082] Figure 7 1 is a diagram showing an example of the configuration 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 channel 170. The shortest distance between the end 175 of the protective film 150-1 and the second electrode 50 is set to Dmin (μm). If the flight distance FD shown in formula (5) is less than the shortest distance Dmin, it is possible to suppress the remaining portion 162 from scattering to the second electrode 50. That is, the scattering index I only needs to satisfy the following formula:

[0083] Dmin>2.583×I-16599…Formula (6)

[0084] The scattering index I can also satisfy the following formula:

[0085] 0.8×Dmin>2.583×I-16599…Formula (7)

[0086] In this case, it is possible to further suppress the excess portion 162 from scattering to the second electrode 50 .

[0087] The scattering index I may be below 6000. Figure 6 As shown in FIG. 1 , when the scattering index I becomes equal to or less than 6000, the flying distance of the excess portion 162 becomes 0. Therefore, it is possible to further suppress the excess portion 162 from scattering to the second electrode 50 .

[0088] The larger the width W1 of the protective film 150-1 is, the smaller the scattering index I can be. The width W1 can be greater than 0.15 mm, greater than 0.2 mm, greater than 0.3 mm, greater than 0.5 mm, or greater than 0.7 mm. The width W1 can be greater than 0.5 times the width W2, or greater than 0.75 times. The width W1 can be greater than the width W2. In addition, the width of the end 175 in the Y-axis direction can also be greater than the width of any other part in the Y-axis direction. The width of the protective film 150-1 can increase in a conical shape toward the end 175, or can increase in a step-like shape toward the end 175. In this case, the width of the end 175 can be less than the width W2, can be the same as the width W2, or can be greater than the width W2.

[0089] The smaller the length L1 of the protective film 150-1, the smaller the scattering index I. The length L1 may be less than 3 mm, less than 2 mm, or less than 1.5 mm. The length L1 may be less than 1.3 times the length L2, less than the length L2, or less than 0.5 times the length L2.

[0090] The smaller the arithmetic mean roughness Ra of the surface of the protective film 150 - 1 is, the smaller the scattering index I can be. The arithmetic mean roughness Ra may be 2500 μm or less, 2000 μm or less, 1500 μm or less, or 1000 μm or less.

[0091] The maximum distance between the end 175 of the protective film 150-1 and the second electrode 50 is set to Dmax (μm). The maximum distance Dmax can be the maximum distance in the X-axis direction of the protective film 150-1, or the maximum distance in all directions. When the flight distance FD shown in formula (5) is greater than the maximum distance Dmax, the remaining portion 162 flies over the second electrode 50, so that the remaining portion 162 can be suppressed from adhering to the second electrode 50. That is, the scattering index I only needs to satisfy the following formula:

[0092] Dmax<2.583×I-16599…Formula (8),

[0093] The scattering index I can also satisfy the following formula:

[0094] 1.2×Dmax<2.583×I-16599…Formula (9).

[0095] In this case, it is possible to further suppress the excess portion 162 from scattering to the second electrode 50 .

[0096] The smaller the width W1 of the protective film 150-1 is, the greater the scattering index I can be. The width W1 can be less than 0.1 mm, less than 0.075 mm, or less than 0.05 mm. The width W1 can be less than 0.5 times the width W2, less than 0.3 times, or less than 0.1 times. In addition, the width of the protective film 150-1 can decrease in a conical shape toward the end 175, or can decrease in a stepped shape toward the end 175.

[0097] The longer the length L1 of the protective film 150 - 1 is, the greater the scattering index I can be. 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 of the length L2, or 1.7 times or more of the length L2.

[0098] 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.

[0099] In the case where the protective film 150-1 has a plurality of first portions 151, at least one of the first portions 151 may satisfy any one of the conditions of the above-mentioned scattering index I. As an example, the first portion 151 whose end portion 175 is closest to the gate pad (e.g., the second electrode 50-2) among the plurality of first portions 151 may satisfy the condition of the above-mentioned scattering index I. In another example, all of the first portions 151 may satisfy any one of the conditions of the above-mentioned scattering index I. Alternatively, any one of the first portions 151 may satisfy the condition of formula (6) or formula (7), and any other first portion 151 may satisfy the condition of formula (8) or formula (9).

[0100] Figure 8 FIG. 2 is a diagram showing another example of the AA cross section. Figure 4 In the example of , a space (solder channel 170) is formed above the protective film 150-1, and the solder portion 160 is provided between the space and the lead frame 130. That is, the lead frame 130 is not exposed in the solder channel 170. Figure 8 In the example of FIG. 1 , there is a region where the solder portion 160 is not provided between the space (solder channel 170 ) above the protective film 150 - 1 and the lead frame 130 . That is, the bottom surface of the lead frame 130 is exposed in the solder channel 170 .

[0101] The arithmetic mean roughness of the bottom surface of the lead frame 130 exposed in the solder channel 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 in the solder channel 170, the friction coefficient of the inner wall of the solder channel 170 can be reduced, and the flight distance of the remaining portion 162 can be reduced compared to the flight distance FD shown in formula (5). As a result, the remaining portion 162 can be prevented from reaching the second electrode 50. The area of ​​the bottom surface of the lead frame 130 exposed in the solder channel 170 can be more than half of the area of ​​the upper surface of the protective film 150-1, can be more than 0.75 times, can be 1 times, or can be more than 1 times.

[0102] It is also possible to form a concavoconvex shape on the bottom surface of the lead frame 130 exposed to the solder channel 170 so that the arithmetic mean roughness of the bottom surface of the lead frame 130 is greater than the arithmetic mean roughness Ra of the protective film 150-1. By increasing the arithmetic mean roughness of the bottom surface of the lead frame 130, the flying distance of the remaining portion 162 can be increased. Thus, the remaining portion 162 can easily pass over the second electrode 50. The arithmetic mean roughness of the bottom surface of the lead frame 130 can be more than 2 times, more than 5 times, or more than 10 times the arithmetic mean roughness Ra of the protective film 150-1. The area of ​​the bottom surface of the lead frame 130 exposed in the solder channel 170 can be more than half of the area of ​​the upper surface of the protective film 150-1, can be more than 0.75 times, can be 1 time, or can be more than 1 time.

[0103] Although the present invention has been described above using embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is obvious to those skilled in the art that various changes or improvements can be made to the above embodiments. According to the description of the claims, the method to which such changes or improvements are made can also be included in the technical scope of the present invention.

Claims

1. A semiconductor device, characterized in that: have: Semiconductor substrates; A first electrode disposed above the semiconductor substrate; a protective film having a portion disposed above the first electrode; a solder portion arranged in contact with the upper surface of the first electrode, arranged with the protective film sandwiched therebetween in a first direction parallel to the upper surface, and arranged without sandwiching the protective film in a second direction different from the first direction; a lead frame fixed by the solder portion and arranged above the protective film; as well as a second electrode disposed above the semiconductor substrate and located outside in the second direction of an end portion of the protective film disposed below the lead frame in the second direction; When the width of the protective film disposed below the lead frame in the first direction is set to W1 (μm), the length of the protective film in the second direction is set to L1 (μm), the arithmetic mean roughness of the surface of the protective film is set to Ra (μm), the scattering index is set to I, and the shortest distance between the end of the protective film and the second electrode is set to Dmin (μm), the following formula is satisfied: I=((Ra / 4)×L1) / (2×(W1×W1 / π) 0.5 ), Dmin>2.583×I-16599.

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

3. The semiconductor device according to claim 1, wherein: The scattering index is 6,000 or less.

4. A semiconductor device, characterized in that: have: Semiconductor substrates; A first electrode disposed above the semiconductor substrate; a protective film having a portion disposed above the first electrode; a solder portion arranged in contact with the upper surface of the first electrode, arranged with the protective film sandwiched therebetween in a first direction parallel to the upper surface, and arranged without sandwiching the protective film in a second direction different from the first direction; a lead frame fixed by the solder portion and arranged above the protective film; as well as a second electrode disposed above the semiconductor substrate and located outside in the second direction of an end portion of the protective film disposed below the lead frame in the second direction; When the width of the protective film disposed below the lead frame in the first direction is set to W1 (μm), the length of the protective film in the second direction is set to L1 (μm), the arithmetic mean roughness of the surface of the protective film is set to Ra (μm), the scattering index is set to I, and the maximum distance between the end of the protective film and the second electrode is set to Dmax (μm), the following formula is satisfied: I=((Ra / 4)×L1) / (2×(W1×W1 / π) 0.5 ), Dmax<2.583×I-16599.

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

6. The semiconductor device according to any one of claims 1 to 5, characterized in that The protective film disposed below the lead frame has: Part II; as well as a first portion extending from the second portion in a direction toward the second electrode, wherein a width of the first portion in the first direction is smaller than a width of the second portion in the first direction, The length L1 of the protective film is the length of the first portion in the second direction.

7. The semiconductor device according to any one of claims 1 to 5, characterized in that 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.

8. The semiconductor device according to any one of claims 1 to 5, characterized in that A space is formed above the protective film disposed below the lead frame, and a region where the solder portion is not provided exists between the space and the lead frame.

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