Electronic device and method of manufacturing electronic device

Abstract

The present application provides an electronic device capable of mounting components on a substrate at high density without causing electrical defects, and a manufacturing method for the electronic device. The electronic device has: semiconductor chips (20, 21); and a circuit board (12) whose front surface is covered with a plating film 12a, and in a predetermined component region of the front surface, the semiconductor chips (20, 21) are arranged via first and second solders (16a, 16b). Furthermore, the electronic device is provided with a liquid-proof portion (14) formed on the front surface along the side of the component region of the circuit board (12). Therefore, it is possible to shorten the interval of the semiconductor chips (20, 21) while forming the liquid-proof portion (14) therebetween to suppress the spread of the first and second solders (16a, 16b).

Description

Technical Field

[0001] This invention relates to an electronic device on which components are soldered to a substrate, and a method for manufacturing the electronic device. Background Technology

[0002] Semiconductor devices, as an example of electronic devices, include power devices and are used as power conversion devices. Power devices are, for example, semiconductor chips including IGBTs (Insulated Gate Bipolar Transistors) and power MOSFETs (Metal Oxide Semiconductor Field Effect Transistors). Such semiconductor devices include the semiconductor chip and a ceramic circuit board on which the semiconductor chip is disposed via solder. The ceramic circuit board includes an insulating plate and multiple circuit boards formed on the insulating plate. The semiconductor chip is disposed on any of the multiple circuit boards via solder. Furthermore, there is a situation where gaps are formed around the component areas of the semiconductor chip on the circuit boards. Such gaps serve functions such as semiconductor chip positioning alignment and inhibiting solder diffusion.

[0003] In such semiconductor devices, semiconductor chips are mounted on a circuit board of a ceramic circuit board using solder. By melting and solidifying the solder, the semiconductor chips are fixed to the circuit board. However, molten solder can flow out of the component area of ​​the semiconductor chip. Furthermore, some of the outflowing solder can even cross gaps. Therefore, various techniques have been proposed to prevent solder outflow. For example, a solder flow prevention section composed of linear oxides is formed along the semiconductor chip on the circuit board (see, for example, Patent Document 1). In addition, a coating is formed on the surface of the circuit board, and a non-solder-adhesive portion is formed around the component area of ​​the semiconductor chip in the coating (see, for example, Patent Document 2). In addition, a copper coating is formed on an insulating substrate, and a copper oxide coating is formed in the areas where the semiconductor chip is not mounted (see, for example, Patent Document 3). Furthermore, a first region and a second region with lower solder wettability than the first region are formed around the semiconductor chip bonded by solder on the mounting surface of the mounting component (see, for example, Patent Document 4). Furthermore, when a ceramic circuit board is disposed on a metal substrate via solder, a barrier material is formed around the component area of ​​the ceramic circuit board (for example, see Patent Documents 5 and 6). Additionally, a spacer layer is formed around the component area of ​​a semiconductor chip in a mounting component where a semiconductor chip is mounted via solder (for example, see Patent Document 7). Furthermore, a groove is formed around the semiconductor chip with leads disposed thereon by laser irradiation, and oxide regions are formed on both sides of the groove. The wall of the groove is composed of an oxidized mother substrate and a portion of an oxidized electroplating material (for example, see Patent Document 8).

[0004] Furthermore, the semiconductor chip and ceramic circuit board of such a semiconductor device are sealed by a sealing component. In order to improve the tightness between the sealing component and the ceramic circuit board, a fixing layer consisting of striped recesses is formed around the semiconductor chip on the circuit board (for example, see Patent Document 9).

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2013-247256

[0008] Patent Document 2: Japanese Patent Application Publication No. 2008-177383

[0009] Patent Document 3: Japanese Patent Application Publication No. 8-031848

[0010] Patent Document 4: Japanese Patent Application Publication No. 2009-218280

[0011] Patent Document 5: Japanese Patent Application Publication No. 2010-212723

[0012] Patent Document 6: Japanese Patent Application Publication No. 2006-216729

[0013] Patent Document 7: Japanese Patent Application Publication No. 2016-174053

[0014] Patent Document 8: Japanese Patent Application Publication No. 2017-005149

[0015] Patent Document 9: Japanese Patent Application Publication No. 2016-029676 Summary of the Invention

[0016] Technical issues

[0017] In recent years, there has been a pursuit of miniaturization and increased capacity in semiconductor devices. Furthermore, as the mounting density of semiconductor chips increases, the spacing between them becomes narrower. Therefore, it is difficult to form components between the semiconductor chips to restrict solder flow. If the solder beneath the semiconductor chip melts, it can easily lead to bonding between the chips, resulting in poor contact. This, in turn, reduces the reliability of the semiconductor device.

[0018] The present invention was made in view of this purpose, and its object is to provide an electronic device and a method for manufacturing the electronic device that enables high-density mounting of components on a substrate without causing electrical defects.

[0019] Technical solution

[0020] According to one aspect of the present invention, an electronic device and a method of manufacturing the electronic device are provided, comprising a first component; and a circuit board having a front side coated with a film, wherein the first component is disposed in a first component region on the front side via a first solder, the electronic device having a liquid-resistant portion formed on the front side along a side portion of the first component region of the circuit board, the liquid-resistant portion comprising an oxide film formed by oxidizing the film, and a portion of the film remaining beneath the oxide film.

[0021] Technical effect

[0022] According to the disclosed technology, it is possible to provide an electronic device that can densely mount components on a substrate without causing electrical defects and suppress the reduction of reliability, as well as a method for manufacturing the electronic device. Attached Figure Description

[0023] Figure 1 This is a side view of an electronic device illustrating an embodiment.

[0024] Figure 2This is a top view of the electronic device illustrating an embodiment.

[0025] Figure 3 This is a top view of the circuit board included in the electronic device of the embodiment.

[0026] Figure 4 This is a cross-sectional view of the circuit board included in the electronic device of the embodiment.

[0027] Figure 5 This is a flowchart illustrating a method for manufacturing an electronic device according to an embodiment.

[0028] Figure 6 This is a top view of the ceramic circuit board included in the electronic device of the embodiment.

[0029] Figure 7 This is a top view illustrating the solder coating process in the manufacturing method of an electronic device according to an embodiment.

[0030] Figure 8 This is a top view (one of the embodiments) of the reflow soldering process in the manufacturing method of the electronic device.

[0031] Figure 9 This is a top view (second example) of the reflow soldering process in the manufacturing method of the electronic device according to the embodiment.

[0032] Figure 10 This is a top view (third one) of the reflow soldering process in the manufacturing method of the electronic device according to the embodiment.

[0033] Figure 11 This is a top view (one of the examples) of the reflow soldering process in the manufacturing method of an electronic device.

[0034] Figure 12 This is a top view (second example) of the reflow soldering process in the manufacturing method of an electronic device for reference.

[0035] Figure 13 This is a top view (one of the examples) of the formation of a liquid-resistant portion formed on a ceramic circuit board of an electronic device in an embodiment.

[0036] Figure 14 This is a top view (second example) of the formation of a liquid-resistant portion formed on a ceramic circuit board of an electronic device in an embodiment.

[0037] Symbol Explanation

[0038] 10 Ceramic circuit board

[0039] 11 Insulation Board

[0040] 12 circuit boards

[0041] 12a coating

[0042] 13 Metal Plates

[0043] 14. Liquid-resistant section

[0044] 14a Corrosion-resistant section

[0045] 14b Heat-affected zone

[0046] 15 bond wires

[0047] 16a First Solder

[0048] 16b Second Solder

[0049] Semiconductor chips 20, 21, 23a, 23b, 23c, 23d

[0050] Component areas 20a and 21a

[0051] 22 Electronic components

[0052] 30 Contact components

[0053] 31 Solder board

[0054] 40 External connection terminals

[0055] 45 Sealing components

[0056] 50 Electronic devices Detailed Implementation

[0057] The embodiments will now be described with reference to the accompanying drawings. It should be noted that in the following description, "front" and "top surface" are used interchangeably. Figure 1 In the electronic device 50, the upward-facing side is indicated. Similarly, "up" is used in... Figure 1 In the electronic device 50, the direction of the upper side is indicated. "Back side" and "lower surface" are... Figure 1 In the electronic device 50, the downward-facing side is indicated. Similarly, "down" is... Figure 1 In the electronic device 50, the direction of the lower side is indicated. The same directionality may be indicated in other figures as needed. The terms "front," "upper surface," "upper," "back," "lower surface," "lower," and "side" are merely convenient expressions for determining relative positional relationships and do not limit the technical concept of the invention. For example, "upper" and "lower" do not necessarily mean the vertical direction relative to the ground. That is, the directions of "upper" and "lower" are not limited to the direction of gravity.

[0058] use Figure 1 and Figure 2 The electronic device used in the implementation method will be described. Figure 1 This is a side view illustrating an embodiment of the electronic device. Figure 2This is a top view illustrating an electronic device according to an embodiment. It should be noted that in this embodiment, an example is given of using a semiconductor device as the electronic device. Furthermore, Figure 1 Dashed lines are used to represent sealing components. Figure 2 The illustration of the sealing component is omitted. Furthermore, the description of the housing for the ceramic circuit board 10, etc., in the electronic device 50 is omitted. In this embodiment, the multiple circuit boards 12, multiple semiconductor chips 20, 21, multiple contact components 30, multiple bonding wires 15, and multiple external connection terminals 40 are described using the same symbols without differentiation. It should be noted that other components are also described using the same symbols without differentiation.

[0059] like Figure 1 and Figure 2 As shown, the electronic device 50 includes a ceramic circuit board 10 and semiconductor chips 20 and 21 bonded to the front side of the ceramic circuit board 10. The electronic device 50 also includes a contact member 30 bonded to the front side of the ceramic circuit board 10. The semiconductor chips 20 and 21 and the contact member 30 are bonded to the front side of the ceramic circuit board 10 via solder (not shown) as a bonding material. Additionally, the electronic device 50 includes a bonding wire 15 that electrically connects the front side of the ceramic circuit board 10 to the main electrodes of the semiconductor chips 20 and 21. Furthermore, an external connection terminal 40 is press-fitted onto the contact member 30. Moreover, the electronic device 50, along with the semiconductor chips 20 and 21 on the front side of the ceramic circuit board 10, is sealed by a sealing member 45 such that the front end of the external connection terminal 40 mounted on the contact member 30 protrudes.

[0060] The ceramic circuit board 10 includes an insulating plate 11, a plurality of circuit boards 12 formed on the front side of the insulating plate 11, and a metal plate 13 formed on the back side of the insulating plate 11. The insulating plate 11 is made of a material with excellent thermal conductivity. Such a material is ceramic, which has high thermal conductivity. Examples of ceramics include alumina, aluminum nitride, and silicon nitride. Furthermore, the thickness of the insulating plate 11 is 0.5 mm or more and 2.0 mm or less. The plurality of circuit boards 12 are made of a base material with excellent electrical conductivity. Such a material is, for example, copper or a copper alloy. Moreover, to improve corrosion resistance, a coating 12a (see reference) is formed on the surface of the circuit boards 12 by electroplating. Figure 4The electroplating material used for the coating is, for example, nickel or a nickel alloy. Nickel-phosphorus alloys and nickel-boron alloys are preferred as nickel alloys. The metal plate 13 is made of a metal with excellent thermal conductivity. Such a metal is, for example, aluminum, iron, silver, copper, or an alloy including at least one of these. The thickness of the metal plate 13 is 0.1 mm or more and 2.0 mm or less. To improve corrosion resistance, a coating can be formed on the surface of the metal plate 13 by electroplating. The electroplating material used for the coating is, for example, nickel, a nickel-phosphorus alloy, or a nickel-boron alloy. Additionally, a cooling module (not shown) can be mounted on the back of the metal plate 13. It should be noted that the insulating plate 11 appears rectangular, for example, when viewed from above. Furthermore, the metal plate 13, when viewed from above, is a rectangle with an area smaller than the insulating plate 11 and a total area larger than the circuit board 12. Therefore, the ceramic circuit board 10 is, for example, rectangular.

[0061] A liquid-resistant portion 14 is suitably formed on the circuit board 12. The liquid-resistant portion 14 is formed in the gap between the components of the circuit board 12 where semiconductor chips 20 and 21 are disposed. Additionally, the liquid-resistant portion 14 is formed in the gap between the semiconductor chip 20 and the contact component 30 (external connection terminal 40). Furthermore, the liquid-resistant portion 14 is formed in the gap between the semiconductor chip 21 and the end of the circuit board 12 (the area where the bonding wire 15 is joined). This liquid-resistant portion 14 is formed along the length or width direction of the ceramic circuit board 10. It should be noted that the formation position and direction of the liquid-resistant portion 14 are examples, and it can be formed at the required position and direction. The liquid-resistant portion 14 will be described in detail later.

[0062] As a ceramic circuit board 10 with such a configuration, a DCB (Direct Copper Bonding) substrate or an AMB (Active Metal Brazed) substrate can be used. Alternatively, a cooling module (not shown) can be mounted on the back side of the metal plate 13 of the ceramic circuit board 10 via a thermally conductive bonding material. This further improves the heat dissipation of the electronic device 50. It should be noted that the thermally conductive bonding material is, for example, thermal paste, solder, or silver solder. The thermal paste is, for example, silicon mixed with filler containing metal oxides. The cooling module is suitable as a module made of a metal with excellent thermal conductivity. Such metals are, for example, aluminum, iron, silver, copper, or alloys including at least one of these. Furthermore, the cooling module is, for example, a cooling device having a heat sink and utilizing a liquid refrigerant, the heat sink having one or more heat sink fins.

[0063] Semiconductor chip 20 includes switching elements such as IGBTs and power MOSFETs made of silicon or silicon carbide. Such semiconductor chip 20 is rectangular in top view, for example, having a drain electrode (or collector) as the main electrode on the back side, and a gate electrode and a source electrode (or emitter) as the control electrode and main electrode, respectively, on the front side. It should be noted that the gate electrode is located at the center of the short side of the front side of semiconductor chip 20. Additionally, semiconductor chip 21 includes a diode. The diode is an SBD (Schottky Barrier Diode), a PiN (P-intrinsic-N) diode, or a FWD (Freewheeling Diode). Such semiconductor chip 21 has a cathode as the main electrode on the back side and an anode as the main electrode on the front side. The back sides of the aforementioned semiconductor chips 20 and 21 are bonded to a predetermined circuit board (not shown). It should be noted that semiconductor chips 20 and 21 are bonded to circuit board 12 via solder (not shown). The solder will be described later. Furthermore, although the illustration is omitted, RC (Reverse-Conducting) IGBTs, which simultaneously function as IGBTs and FWDs, can be used instead of semiconductor chips 20 and 21. Additionally, electronic component 22 is arranged across a pair of circuit boards 12. Electronic component 22 is, for example, a thermistor or a current sensor. It should be noted that the thickness of such semiconductor chips 20 and 21 is, for example, between 180 μm and 220 μm, with an average thickness of approximately 200 μm.

[0064] Bonding wires 15 are suitably electrically connected between semiconductor chips 20, 21 and circuit board 12, or suitably electrically connected between multiple semiconductor chips 20, 21. Such bonding wires 15 are made of a material with excellent conductivity. Such materials are, for example, gold, silver, copper, aluminum, or alloys including at least one of these. Furthermore, the diameter of the bonding wires 15 for control current flow is, for example, 110 μm or more and 200 μm or less. The diameter of the bonding wires 15 for main current flow can be, for example, 350 μm or more and 600 μm or less.

[0065] The contact component 30 includes: a main body having a cylindrical through hole formed therein; and flanges respectively disposed at the open ends of the main body. The through hole can be cylindrical or polygonal. The contact component 30 is made of a metal with excellent electrical conductivity. Such a metal is, for example, silver, copper, nickel, or an alloy including at least one of these. To improve corrosion resistance, a coating can be formed on the surface of the contact component 30 by electroplating. The electroplating material used for the coating is, for example, nickel, nickel-phosphorus alloy, or nickel-boron alloy.

[0066] The external connection terminal 40 has a rod-shaped main body and tapered front ends formed at both ends of the main body. The main body is prismatic. The length of the diagonal of the cross-section of the external connection terminal 40 is a few percent longer than the diameter of the main body of the contact member 30. Therefore, the external connection terminal 40 can be pressed into the contact member 30. Furthermore, the external connection terminal 40 is also made of a metal with excellent electrical conductivity. Such a metal is, for example, silver, copper, nickel, or an alloy including at least one of these. To improve corrosion resistance, a coating can be formed on the surface of the external connection terminal 40 by electroplating. It is desirable that the electroplating material used for the coating is nickel or an alloy containing nickel. Examples of nickel-containing alloys include, for example, nickel-phosphorus alloys and nickel-boron alloys.

[0067] Furthermore, the solder used to bond the semiconductor chips 20, 21 and the contact components 30 to the circuit board 12 is primarily lead-free solder. The lead-free solder has at least one alloy selected from the following: an alloy of tin and silver, an alloy of tin and antimony, an alloy of tin and zinc, and an alloy of tin and copper. Additionally, the solder may contain additives. These additives are, for example, copper, bismuth, indium, nickel, germanium, cobalt, or silicon. Furthermore, the solder composition for bonding the semiconductor chips 20, 21 is preferably different from that for bonding the contact components 30. In this case, the solder for bonding the semiconductor chips 20, 21 is less prone to voids and has high-temperature resistance. For example, such a solder is an alloy with tin and antimony as its main components. The solder for bonding the wiring terminals such as the contact components 30 has a lower modulus of elasticity than the solder below the semiconductor chips 20, 21. The solder below the contact components 30 is, for example, an alloy with tin and silver as its main components. Furthermore, the solder bonding the semiconductor chips 20 and 21 can be thinner than the solder bonding the contact member 30. The thickness of the solder below the semiconductor chips 20 and 21 is 0.05 mm or more and 0.25 mm or less. The thickness of the solder below the contact member 30 is 0.10 mm or more and 0.50 mm or less. Since the elastic modulus of the solder below the semiconductor chips 20 and 21 is higher than that of the solder below the contact member 30, the thickness of the solder on the semiconductor chips 20 and 21 can be thinner than that of the solder on the contact member 30. Therefore, heat dissipation from the semiconductor chips 20 and 21 during operation of the electronic device 50 can be better achieved. As described above, the solder below the contact member 30 is thicker. Therefore, the solder below the contact member 30 can withstand the stress when the external connection terminal 40 is inserted into the through hole of the contact member 30, and can suppress the generation of cracks and peeling in the solder. Therefore, damage to the electronic device 50 can be prevented.

[0068] The sealing component 45 can be, for example, silicone. Alternatively, the sealing component 45 includes, for example, a thermosetting resin such as epoxy resin, phenolic resin, or maleimide resin, and a filler material contained in the thermosetting resin. As an example of such a sealing component 45, it includes epoxy resin and a filler material such as silica, alumina, boron nitride, or aluminum nitride filled in the epoxy resin as a filler.

[0069] Next, using Figure 3 and Figure 4 The liquid-resistant portion 14 formed on the circuit board 12 will be described. Figure 3 This is a top view of the circuit board included in the electronic device of the embodiment. Figure 4 This is a cross-sectional view of the circuit board included in the electronic device of the embodiment. It should be noted that... Figure 3 Magnification Figure 2 The dashed area of ​​circuit board 12. Additionally... Figure 4 yes Figure 3 A cross-sectional view of the single-dotted dashed line YY. It should be noted that... Figure 3 and Figure 4 The figure shows a coating 12a formed on the surface of a circuit board 12.

[0070] Figure 3 The liquid-resistant portion 14 shown is linearly formed in the coating 12a between a pair of semiconductor chips 20 and 21. It should be noted that in... Figure 3 The device includes three pairs of semiconductor chips 20 and 21. The long side of the semiconductor chip 20 is arranged along the formation direction of the liquid-resistant portion 14 (described later). In this configuration, the semiconductor chip 20 is arranged such that the short side where the gate electrode is located does not face the liquid-resistant portion 14. With the long side of the semiconductor chip 20 along the formation direction of the liquid-resistant portion 14, compared to the case where the short side is along the formation direction of the liquid-resistant portion 14, the position of the solder end can be restricted by a longer distance, thus stabilizing the position of the semiconductor chip 20. It should be noted that, considering the lead configuration, the semiconductor chip 20 only needs to be arranged such that the side where the gate electrode is located does not face the liquid-resistant portion 14. The liquid-resistant portion 14 can block solder. This liquid-resistant portion 14 includes a resist portion 14a and a heat-affected zone 14b. The resist portion 14a is an oxide film. The oxide film is, for example, a nickel oxide film. This resist portion 14a is formed by oxidizing the plating film 12a by laser irradiation. It should be noted that laser irradiation can be either a weld laser that emits laser light continuously or a spot laser that irradiates with pulsed light. Figure 3 The image shows a case where laser irradiation is performed using a weld laser. Therefore, Figure 3The liquid-resistant portion 14 appears as a linear laser mark (or a dotted line mark in the case of a spot laser) when viewed from above. Furthermore, as described later, the liquid-resistant portion 14 is formed by laser scanning irradiation. Specifically, the resist portion 14a is formed by each laser scan contacting with multiple laser marks formed along each other, or by partially overlapping them. The resist portion 14a thus formed preferably has a thickness of 40 nm or more before solder bonding. Furthermore, the thickness of the resist portion 14a (oxide film) after solder bonding is preferably 25 nm or more. The reason for the reduction in the thickness of the resist portion 14a (oxide film) before and after solder bonding is that a portion of the oxide film is reduced by the flux included in the solder. Additionally, the minimum width of the resist portion 14a can be set to 150 μm.

[0071] The heat-affected region 14b is an oxide film formed along the resist portion 14a. As described above, to form the resist portion 14a, laser scanning is performed on the coating 12a by laser irradiation. During this process, as the resist portion 14a is formed, the coating 12a on both sides of the resist portion 14a is affected by the heat from the laser. As a result, the heat-affected region 14b is formed on both sides of the resist portion 14a. Furthermore, the larger the output of the laser used to form the resist portion 14a, the wider the width of the heat-affected region 14b. In addition, the width of the heat-affected region 14b also widens in relation to the widening of the resist portion 14a. If the width of the resist portion 14a is greater than or equal to a predetermined value, the width of the heat-affected region 14b becomes fixed. Figure 4 As shown, the heat-affected zone 14b is associated with the reduction of the heat generated by the laser as it moves away from the corrosion-resistant part 14a.

[0072] Regarding the liquid-resistant capability of the liquid-resistant portion 14 with this configuration, the liquid-resistant capability of the corrosion-resistant portion 14a is higher than that of the heat-affected zone 14b. Furthermore, regarding the liquid-resistant capability of the heat-affected zone 14b, the liquid-resistant capability on the corrosion-resistant portion 14a side is higher than that on the outer side. Therefore, for the liquid-resistant portion 14, as... Figure 4 As shown, although the first and second solders 16a and 16b somewhat affect the outer side of the liquid-resistant portion 14, they do not affect the center of the liquid-resistant portion 14, which includes the resist portion 14a. Furthermore, since this liquid-resistant portion 14 is formed by laser irradiation, there is a portion of residual coating 12a beneath the liquid-resistant portion 14. The combined thickness of the liquid-resistant portion and the portion of residual coating is preferably 6 μm or more. The thickness of the portion of residual coating beneath the liquid-resistant portion is preferably 5 μm or more.

[0073] It should be explained that Figure 3The liquid-resistant portion 14 shown is formed relative to the semiconductor chips 20 and 21 as an example. The resist portion 14a of the liquid-resistant portion 14 is formed on the coating 12a under the following conditions: First, the resist portion 14a is preferably separated from the semiconductor chips 20 and 21 by at least 0.3 mm. Furthermore, the resist portion 14a is preferably separated from the end of the circuit board 12 by at least 0.5 mm. The width of the resist portion 14a is preferably 0.4 mm or more and 0.5 mm or less. Where it is difficult for the resist portion 14a to be separated from the semiconductor chips 20 and 21 by at least 0.3 mm, and difficult to be separated from the end of the circuit board 12 by at least 0.5 mm, the width of the resist portion 14a is preferably set to at least 0.15 mm. Furthermore, when the resist portion 14a is separated from the end of the circuit board 12 by at least 0.5 mm at its end, its length preferably extends a maximum of 1.0 mm from the end face of the semiconductor chips 20 and 21. Additionally, the resist portion 14a is preferably separated from the contact member 30 by at least 0.3 mm. If a distance of 0.3 mm or more cannot be adopted, it is preferable to set the width of the corrosion-resistant part 14a to be 0.1 mm or more and 0.2 mm or less.

[0074] Next, according to Figure 5 The process shown utilizes the diagrams illustrating each step. Figures 6-10 The manufacturing method of such electronic device 50 will be described. Figure 5 This is a flowchart illustrating a method for manufacturing an electronic device according to an embodiment. Figure 6 This is a top view of the ceramic circuit board included in the electronic device of the embodiment. Figure 7 This is a top view illustrating the solder coating process in the manufacturing method of an electronic device according to an embodiment. Figures 8-10 This is a top view of the reflow soldering process in the manufacturing method of the electronic device according to the embodiment, corresponding to Figure 3 The part.

[0075] The electronic device 50 is manufactured according to the manufacturing process (flow) shown below. The following manufacturing processes are performed manually or by the manufacturing device as needed.

[0076] [Step S10]

[0077] Prepare semiconductor chips 20 and 21, a ceramic circuit board 10, and contact components 30. Components necessary for manufacturing the electronic device 50 are prepared in advance, not limited to these. It should be noted that the ceramic circuit board 10 has an insulating plate 11 and multiple circuit boards 12 formed on the front side of the insulating plate 11 (see reference). Figure 6 ), and a metal plate 13 formed on the back of the insulating plate 11. It should be noted that, in Figure 6 In the diagram, the dashed rectangles marked on the multiple circuit boards 12 indicate the component areas 20a and 21a of the subsequent semiconductor chips 20 and 21. Additionally, although in Figure 6 The diagram is omitted, but a coating is formed on the surface of the circuit board 12 through electroplating.

[0078] [Step S11]

[0079] like Figure 6 As shown, liquid-resistant portions 14 are formed on the circuit board 12 of the ceramic circuit board 10 by laser irradiation. The laser irradiation is, for example, using a YAG laser or a YVO4 laser. Using such a laser device, the resist portion 14a is formed by repeatedly scanning a predetermined area with a weld laser or a spot laser. It should be noted that the predetermined area is, for example, between the areas where semiconductor chips 20 and 21 are disposed, and between the areas where semiconductor chips 20 and 21 and contact members 30 are disposed respectively (see reference). Figure 2 (If necessary, the area may also be configured with multiple contact components 30.) The width of the anti-corrosion portion 14a can be appropriately controlled according to the number of laser scans. Figure 3 The width of the corrosion-resistant portion 14a shown is an example. By increasing or decreasing the number of laser scans compared to the current situation, the width of the corrosion-resistant portion 14a can be increased. Figure 3 The width of the resist portion 14a shown can be wide or narrow. The laser irradiation conditions can be appropriately set between a scanning speed of 1000 mm / s, a scanning interval of 40 μm, a spot size of -10 to 10, and a pulse frequency of 25 kHz to 60 kHz. At this time, the plating 12a on the surface of the circuit board 12 is oxidized by laser irradiation, and the laser scanning and laser output are performed to the extent that the base material of the circuit board 12 is not exposed. Furthermore, along with the formation of the resist portion 14a, heat-affected zones 14b are formed on both sides of the resist portion 14a. The width of the unilateral heat-affected zone 14b thus formed is, for example, 50 μm or more.

[0080] [Step S12]

[0081] like Figure 7 As shown, solder plates 31 are respectively disposed in the component regions 20a and 21a of the semiconductor chips 20 and 21 and the placement region of the contact component 30 on the circuit board 12 of the ceramic circuit substrate 10. It should be noted that, instead of solder plates 31, solder can also be applied to the circuit board 12 of the ceramic circuit substrate 10 using, for example, a distributor. It should be noted that the solder plates for the semiconductor chips 20 and 21 are quadrilateral, and the solder plate for the contact component 30 is circular. Figure 7 Solder board 31 is shown.

[0082] It should be noted that the solder board 31 in this case uses a solder board of the same material. This solder board 31 is made of lead-free solder, which is primarily composed of at least one of the following alloys: tin-silver-copper alloy, tin-zinc-bismuth alloy, tin-copper alloy, and tin-silver-indium-bismuth alloy. In addition, the solder board 31 includes a flux that removes oxides from the circuit board 12 (coating 12a). The flux may contain, for example, epoxy resin, carboxylic acid, rosin resin, activator, and solvent, and may contain other components as needed. Furthermore, such a solder board 31 may include additives such as nickel, germanium, cobalt, or silicon.

[0083] [Step S13]

[0084] On the solder board 31 configured in step S12, semiconductor chips 20 and 21 and contact components 30 are assembled using a mounting device (not shown). It should be noted that electronic component 22 is also assembled in the same manner at this time.

[0085] [Step S14]

[0086] In step 13, with the semiconductor chips 20 and 21 and contact components 30 assembled on the circuit board 12 of the ceramic circuit substrate 10 via the solder plate 31, it is moved into the reflow oven. For example, Figure 8 As shown, at this time, the semiconductor chips 20 and 21 on the circuit board 12 (coating 12a) are mounted on the solder plate 31. In this state, the furnace pressure is reduced, and a reflow process (reflow soldering) is performed. The reflow process temperature is, for example, 250°C or higher and 300°C or lower. As a result, the solder plate 31 between the coating 12a and the semiconductor chips 20 and 21 melts. Figure 9 As shown, the first and second solders 16a and 16b, molten from the solder plate 31, diffuse to the outer side of the semiconductor chips 20 and 21. At this time, the semiconductor chips 20 and 21 may sometimes move over the diffused first and second solders 16a and 16b. Furthermore, the diffused first and second solders 16a and 16b also affect the liquid-resistant portion 14. Depending on the situation, the first and second solders 16a and 16b may sometimes bond to the liquid-resistant portion 14. Subsequently, the first and second solders 16a and 16b on the liquid-resistant portion 14 are blocked by the liquid-resistant portion 14 due to its liquid-resistant properties, thereby creating a predetermined gap. Accompanying this, as... Figure 10 As shown, the semiconductor chips 20 and 21, which were misaligned on the diffused first and second solders 16a and 16b, also return to their predetermined configuration positions. Furthermore, the semiconductor chips 20 and 21 are bonded to the circuit board 12 (coating 12a) using the first and second solders 16a and 16b that have solidified from the molten first and second solders 16a and 16b (see reference). Figure 4Similarly, the contact component 30 is bonded to the circuit board 12 (coating 12a) using solder.

[0087] [Step S15]

[0088] The ceramic circuit board 10, with semiconductor chips 20 and 21 bonded to each circuit board 12 and contact components 30, is removed from the reflow oven. Then, using an ultrasonic bonding tool (not shown), predetermined areas of each circuit board 12 of the ceramic circuit board 10 are electrically connected to the semiconductor chips 20 and 21 using bonding wires 15. After connecting the bonding wires 15, external connection terminals (not shown) are pressed into each contact component 30.

[0089] [Step S16]

[0090] A ceramic circuit board 10, to which semiconductor chips 20 and 21 and contact components 30 are bonded and electrically connected by bonding wires 15, is assembled into a housing and sealed using a sealing component 45. Thus, a product is manufactured. Figure 1 and Figure 2 The electronic device 50 shown.

[0091] Here, utilizing Figure 11 and Figure 12 The reflow soldering of step S14 described above will be explained when a gap is formed at the location where a liquid-resistant portion 14 is formed, but the liquid-resistant portion 14 is not formed on the circuit board 12. Figure 11 and Figure 12 This is a top view of the reflow soldering process in the manufacturing method of the electronic device of the reference example. It should be noted that, except for the gap 140 provided to replace the liquid-resistant part 14, the electronic device of the reference example has the same configuration as the electronic device 50, and is labeled with the same symbols; its description is omitted. Furthermore, Figure 11 and Figure 12 Showing the corresponding Figure 8 and Figure 10 The state of affairs.

[0092] Semiconductor chips 20 and 21 are disposed on a circuit board 12 (coating 12a) with gaps 140 formed on a ceramic circuit substrate 10 via a solder plate 31, and then transferred to a reflow oven (see reference). Figure 11 It should be noted that the gap 140 is a concave groove formed in the circuit board 12 (plating 12a). In this state, if the furnace is depressurized and heated to the reflow processing temperature, the solder plate 31 between the plating 12a and the semiconductor chips 20, 21 melts. The first and second solders 16a, 16b molten from the solder plate 31 diffuse to the outside of the semiconductor chips 20, 21. Therefore, for example, this causes the circuit board 12 to ( Figure 12The semiconductor chip 20 in the middle rotates or shifts at that position due to the diffusion of the first solder 16a. A portion of the rotated semiconductor chip 20 is positioned on the gap 140 via the first solder 16a. If the first solder 16a fills the gap 140, voids may be generated within the gap 140. If voids are generated in this way, the heat dissipation relative to the semiconductor chip 20 will be reduced. It should be noted that this situation can also occur on the semiconductor chip 21 side.

[0093] Additionally, on circuit board 12 ( Figure 12 (on the left and right sides), causing the first and second solders 16a and 16b to bond in the gap. In this case, the semiconductor chips 20 and 21 are electrically connected, resulting in an electrical malfunction of the electronic device 50.

[0094] Therefore, the aforementioned electronic device 50 includes: semiconductor chips 20 and 21 as components; and a circuit board 12, the front side of which is coated with a film 12a, and the semiconductor chips 20 and 21 are disposed in a predetermined component area on the front side via first and second solders 16a and 16b. Furthermore, the electronic device 50 forms a liquid-resistant portion 14 on the front side along the side of this component area of ​​the circuit board 12. This liquid-resistant portion 14 includes an oxide film formed by oxidizing the film 12a, and a portion of the film 12a remains beneath the oxide film. Thus, since the first and second solders 16a and 16b are blocked by the liquid-resistant portion 14, the diffusion of the first and second solders 16a and 16b is suppressed. In addition, since the liquid-resistant portion 14 is formed by laser irradiation, it can be formed even in a narrow area. Therefore, while shortening the spacing between semiconductor chips 20 and 21, a liquid-resistant portion 14 can be formed between the semiconductor chips 20 and 21 to suppress the diffusion of the first and second solders 16a and 16b. Furthermore, it is not necessary to form gaps in the circuit board 12 to suppress the diffusion of the first and second solders 16a and 16b. Therefore, a decrease in the flexural strength of the circuit board 12 can be prevented. Therefore, semiconductor chips 20 and 21 can be mounted at high density without causing electrical defects; furthermore, a decrease in the strength of the electronic device 50 can be suppressed, and a decrease in the reliability of the electronic device 50 can be suppressed.

[0095] Next, based on Figure 13 and Figure 14 Various examples of forming the liquid-resistant part 14 formed for a circuit board (coated) containing semiconductor chips will be described. Figure 13 and Figure 14 This is a top view showing an example of the formation of a liquid-resistant portion on the ceramic circuit board of the electronic device in the embodiment. It should be noted that... Figure 13 and Figure 14In this circuit board 12, a plating film 12a is formed on the surface. An example is shown where semiconductor chips 23a, 23b, 23c, and 23d are bonded to this plating film 12a using solder (not shown). Furthermore, in... Figure 13 and Figure 14 In the middle, the semiconductor chips 23a, 23b, 23c, and 23d are arranged in two rows and two columns relative to the circuit board 12 (coating 12a).

[0096] exist Figure 13 In (A), the liquid-resistant portion 14 is continuously (in a cross shape) formed between the semiconductor chips 23a, 23b, 23c, and 23d. Furthermore, the liquid-resistant portion 14 is formed around the semiconductor chips 23a, 23b, 23c, and 23d. It should be noted that the liquid-resistant portion 14 may also be continuously (in a cross shape) formed only between the semiconductor chips 23a, 23b, 23c, and 23d. Additionally, in Figure 13 In (B), Figure 13 The liquid-resistant portion 14 in (A) is formed intermittently. It should be noted that... Figure 13 The discontinuous anti-liquid section 14 of (B) is one example. The intervals can also be narrowed to form more dotted lines. Figure 13 In (C), Figure 13 The liquid-resistant part 14 in (A) is also formed intermittently. Among them, in Figure 13 In (C), except for the part where the liquid-proof part 14 intersects, the remaining part is formed intermittently.

[0097] exist Figure 14 In (A), relative to Figure 13 In case (C), the liquid-resistant portion 14 is also formed at the corners of the regions surrounding the semiconductor chips 23a, 23b, 23c, and 23d, respectively. Figure 14 In (B), relative to Figure 13 In case (C), the liquid-resistant portion 14 is continuously formed at the boundaries of semiconductor chips 23a, 23b, 23c, and 23d. Figure 14 In (C), relative to Figure 14 In case (B), the liquid-resistant part 14 is also formed at the corners of the regions surrounding the semiconductor chips 23a, 23b, 23c, and 23d, respectively.

[0098] By forming the liquid-resistant portion 14 in this way, the diffusion of solder under the semiconductor chips 23a, 23b, 23c, and 23d can be prevented, and the arrangement positions of the semiconductor chips 23a, 23b, 23c, and 23d can be maximized. It should be noted that... Figure 13 and Figure 14 The width of the liquid-resistant portion 14 can be appropriately set as needed. Furthermore, the liquid-resistant portion 14 is not limited to... Figure 13 and Figure 14In this case, it can be appropriately formed on the coating 12a for semiconductor chips, etc.

Claims

1. An electronic device, characterized in that, have: The first component, viewed from above, is rectangular; and A circuit board, the front side of which is coated, and the first component is disposed in the first component area on the front side via a first solder. The electronic device has a liquid-resistant portion formed on the front side along the side of the first component region of the circuit board. The liquid-resistant portion includes an oxide film formed by oxidizing the coating, and a portion of the coating remains beneath the oxide film. The first component is disposed adjacent to the liquid-resistant portion in such a manner that the long side of the first component is parallel to the forming direction of the liquid-resistant portion. The liquid-resistant portion is the oxide film comprising a corrosion-resistant portion and a heat-affected zone, wherein the heat-affected zone is formed along the corrosion-resistant portion on both sides of the corrosion-resistant portion. The anti-corrosion part has a higher liquid resistance than the heat-affected zone. Furthermore, regarding the liquid resistance of the heat-affected zone, the anti-corrosion part side has a higher liquid resistance than the outer side. The first component is a semiconductor chip that appears rectangular when viewed from above. The semiconductor chip is arranged adjacent to the liquid-resistant portion such that its long side is parallel to the forming direction of the liquid-resistant portion, and is arranged such that its short side is not opposite to the liquid-resistant portion. The corrosion-resistant part is separated from the first component by more than 0.3 mm. The semiconductor chip has a control electrode on its surface, excluding the long side opposite the liquid-resistant portion. The first solder, viewed from above, covers the edge of the first component side of the heat-affected zone included in the liquid-resistant part.

2. The electronic device according to claim 1, characterized in that, The width of the heat-affected zone is greater than 50 μm.

3. The electronic device according to claim 1, characterized in that, The thickness of the corrosion-resistant part is 25 nm or more.

4. The electronic device according to claim 1, characterized in that, The width of the corrosion-resistant part is more than 100 μm and less than 500 μm.

5. The electronic device according to claim 1, characterized in that, The width of the corrosion-resistant part is more than 100 μm and less than 200 μm.

6. The electronic device according to claim 1, characterized in that, The combined thickness of the liquid-resistant portion and the portion where a portion of the coating remains is 6 μm or more.

7. The electronic device according to claim 1, characterized in that, The thickness of the portion of the coating remaining below the liquid-resistant part is 5 μm or more.

8. The electronic device according to claim 1, characterized in that, The circuit board is made of copper or a copper alloy. The coating is made of nickel or an alloy containing nickel.

9. The electronic device according to claim 1, characterized in that, The liquid-resistant part appears as a straight line or dotted line when viewed from above.

10. The electronic device according to claim 9, characterized in that, The anti-corrosion portion included in the liquid-resistant portion includes a first laser mark formed by irradiating the coating with a laser.

11. The electronic device according to claim 10, characterized in that, The corrosion-resistant portion includes the first laser mark and the second laser mark, wherein the second laser mark is connected to the first laser mark along the first laser mark, or partially overlaps with the first laser mark.

12. The electronic device according to any one of claims 1 to 11, characterized in that, The electronic device also has a second component. The circuit board has a second component area on the front side, which is adjacent to the first component area and the second component is disposed thereon via a second solder, and the liquid-resistant portion is formed in the gap between the first component area and the second component area.

13. The electronic device according to any one of claims 1 to 11, characterized in that, The first component area is located near the end of the circuit board. The liquid-resistant portion is formed along the side of the end side of the first component region.

14. The electronic device according to any one of claims 1 to 11, characterized in that, The electronic device also has a conductive third component. The circuit board has a third component area on the front side, which is adjacent to the first component area and has the third component disposed thereon. The liquid-resistant part is formed in the gap between the first component area and the third component area.

15. A method for manufacturing an electronic device, characterized in that, have: The process of preparing a first component that is rectangular from a top view, and a circuit board with the area of ​​the first component defined on the front side after being coated with a film; A process of forming a liquid-resistant portion on the surface of the coating by irradiating it with a laser, wherein the coating has an oxide film and a portion of the coating remains beneath the oxide film; The process of applying the first solder to the first component area of ​​the coating; The process of arranging the first component adjacent to the liquid-resistant portion on the first solder in such a way that the long side of the first component is parallel to the forming direction of the liquid-resistant portion; and The process of melting the first solder. The liquid-resistant portion formed in the process of forming the liquid-resistant portion is an oxide film comprising a corrosion-resistant portion and a heat-affected region, wherein the heat-affected region is formed along the corrosion-resistant portion on both sides of the corrosion-resistant portion. The heat-affected zone is the area affected by the heat from the laser. The anti-corrosion part has a higher liquid resistance than the heat-affected zone. Furthermore, regarding the liquid resistance of the heat-affected zone, the anti-corrosion part side has a higher liquid resistance than the outer side. The first component is a semiconductor chip that appears rectangular when viewed from above. In the process of configuring the first component, the semiconductor chip is configured adjacent to the liquid-resistant portion such that its long side is parallel to the forming direction of the liquid-resistant portion, and is configured such that its short side is not opposite to the liquid-resistant portion. The corrosion-resistant portion is formed to be separated from the first component by more than 0.3 mm. The semiconductor chip has a control electrode on its surface, excluding the long side opposite the liquid-resistant portion. By melting the first solder, the first solder covers the edge of the first component side of the heat-affected zone included in the liquid-resistant part when viewed from above.

16. The method for manufacturing an electronic device according to claim 15, characterized in that, The thickness of the corrosion-resistant portion formed in the process of forming the liquid-resistant portion is 40 nm or more.

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