JP2013105759A - Circuit device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circuit device where a circuit board is resin-sealed by multiple resin materials which ensure moisture resistance.SOLUTION: In a hybrid integrated circuit device of this invention, an upper surface and side surfaces of a circuit board 14 where a circuit element is disposed on the upper surface are coated by a first sealing resin 18, and a lower surface of the circuit board 14 and side surfaces of the first sealing resin 18 are coated by a second sealing resin 20. Further, a lower surface of the first sealing resin 18 is partially protruded to form a resin protruding part 12 and side surfaces of the resin protruding part 12 are coated by the second sealing resin 20 thereby improving the adhesion strength between the first sealing resin 18 and the second sealing resin 20.

Description

  The present invention relates to a circuit device in which a circuit board having a circuit element incorporated on an upper surface is sealed with a resin.

  As a method for sealing a circuit board in which a hybrid integrated circuit including transistors and chip elements is incorporated on the upper surface, there are a sealing method using a case material and a resin sealing method using a resin.

  In the case of using the case material, the hybrid integrated circuit formed on the upper surface of the circuit board is accommodated in the hollow part of the case material by fitting the lid-like case material provided with the hollow part to the circuit board.

  When resin sealing is employed, the hybrid integrated circuit formed on the upper surface of the circuit board is covered by injection molding using a mold. With reference to FIG. 7A, a structure of the resin-encapsulated hybrid integrated circuit device 100 will be described. In the hybrid integrated circuit 100, first, the upper surface of the circuit board 101 made of a metal such as aluminum is entirely covered with the insulating layer 102. A circuit element is connected to the conductive pattern 103 formed on the upper surface of the insulating layer 102 to constitute a predetermined hybrid integrated circuit. As elements disposed on the upper surface of the circuit board 101, a semiconductor element 105A and a chip element 105B connected by a thin metal wire 107 are illustrated. A lead 104 is fixed to the pad-like conductive pattern 103 at the end of the circuit board 101. The sealing resin 106 is a thermoplastic resin, and covers the upper surface, side surface, and lower surface of the circuit board 101.

  A method for manufacturing the hybrid integrated circuit device 100 will be described with reference to FIG. 7B (Patent Document 1 below). Here, the injection molding is performed with the support member 110 supporting the circuit board 101 from the lower surface. Specifically, the support member 110 is made of a thermoplastic resin, and the inner surface has a size that contacts the lower surface and part of the side surface of the circuit board 101. Further, the outer surface of the support member 110 is in contact with the inner wall lower surface and side surfaces of the mold 112. Therefore, when the circuit board 101 supported by the support member 110 is stored in the cavity 114 of the mold 112, the support member 110 is positioned in the gap between the lower surface of the circuit board 101 and the lower surface of the inner wall of the mold 112. In this state, the circuit board 101 is resin-sealed by injecting a thermoplastic resin into the cavity 114. According to this method, the support member 110 is located in the gap between the lower surface of the circuit board 101 and the lower surface of the inner wall of the mold 112, and it is not necessary to inject liquid resin into the gap. The generation of voids due to the fact that is not partially covered is prevented. In addition, a potting resin 120 is formed on the upper surface of the circuit board 101 so as to cover the circuit elements in order to protect the fine metal wires and the like from the injection pressure during resin sealing.

Japanese Patent No. 3316449

  However, in the above-described manufacturing method, the circuit board 101 is composed of the sealing resin injected into the cavity 114 and the support member 110, so that the interface between the two may remain in the sealing resin. If the adhesiveness between the two resins at this interface is weak, moisture may enter the apparatus via the interface and the circuit board 101 may be short-circuited with the outside.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a circuit device in which a circuit board and circuit elements are resin-sealed with a plurality of resin materials having moisture resistance ensured. There is.

  The circuit device of the present invention includes a circuit board, a circuit element disposed on the upper surface of the circuit board, a first sealing resin that covers the circuit element, the upper surface and side surfaces of the circuit board, and the first sealing. A second sealing resin that covers the lower surface and side surfaces of the resin, and the side surfaces of the resin protrusions that protrude downward from the lower surface of the first sealing resin are covered with the second sealing resin. It is characterized by that.

  According to the present invention, the lower surface of the first sealing resin covering the circuit board is partially protruded as a resin protrusion, and the side surface of the resin protrusion is covered with the outer second sealing resin. Thereby, the adhesion strength between the first sealing resin covering the circuit board and the second sealing resin further sealing the first sealing resin is improved.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the circuit apparatus of this invention, (A) is a perspective view, (B) and (C) are sectional drawings. It is a top view which shows the circuit apparatus of this invention. It is a figure which shows the 1st sealing resin of the circuit apparatus of this invention, (A) is a perspective view, (B) is the perspective view expanded partially. It is a figure which shows the manufacturing method of the circuit apparatus of this invention, (A) is sectional drawing, (B) is a top view which extracts and shows a circuit board. It is a figure which shows the manufacturing method of the circuit apparatus of this invention, (A) is a perspective view which shows the 1st sealing resin shape | molded, (B) And (C) is sectional drawing. It is a figure which shows the manufacturing method of the circuit apparatus of this invention, (A) is a perspective view which shows 2nd sealing resin shape | molded, (B) And (C) is sectional drawing. It is a figure which shows the circuit device of background art, (A) is sectional drawing which shows a hybrid integrated circuit device, (B) is sectional drawing which shows a resin sealing process.

  A configuration of a hybrid integrated circuit device 10 to which the present exemplary embodiment is applied will be described with reference to FIG. 1A is a perspective view of the hybrid integrated circuit device 10, FIG. 1B is a sectional view taken along line BB ′ of FIG. 1A, and FIG. 1C is CC ′. It is sectional drawing in a line.

  In the hybrid integrated circuit device 10, a hybrid integrated circuit composed of a conductive pattern 22 and circuit elements is incorporated on the upper surface of the circuit board 14, and leads 24 electrically connected to the circuit are led out to the outside. Furthermore, the hybrid integrated circuit constructed on the upper surface of the circuit board 14, and the upper surface, side surfaces, and lower surface of the circuit board 14 are integrally covered with a sealing resin 16 made of a thermosetting resin.

  The circuit board 14 is a board made of a metal such as aluminum or copper, and its specific size is, for example, about vertical × horizontal × thickness = 61 mm × 42 mm × 1 mm. Here, a material other than metal may be employed as the material of the circuit board 14, and for example, ceramic or resin material may be employed as the material of the circuit board 14.

  The insulating layer 26 is made of an epoxy resin highly filled with a filler, and is formed so as to cover the entire upper surface of the circuit board 14.

  The conductive pattern 22 is made of a metal film such as copper having a thickness of about 50 μm, and is formed on the surface of the insulating layer 26 so as to realize a predetermined electric circuit. A pad made of the conductive pattern 22 is formed on the side from which the lead 24 is led out.

  The semiconductor element 28 and the chip element 30 (circuit element) are fixed to predetermined portions of the conductive pattern 22 through a bonding material such as solder. As the semiconductor element 28, a transistor, an LSI chip, a diode, or the like is employed. Here, the semiconductor element 28 and the conductive pattern 22 are connected via a thin metal wire 34. As the chip element 30, a chip resistor, a chip capacitor, or the like is employed, and electrodes at both ends are fixed to the conductive pattern 22 via a bonding material such as solder. Further, when the semiconductor element 28 is a power element that emits a large amount of heat, the semiconductor element 28 is fixed to the upper surface of the circuit board 14 via a heat sink made of a metal piece having a thickness of about several millimeters.

  The lead 24 is fixed to a pad provided in the peripheral portion of the circuit board 14 and functions as an external connection terminal through which an input signal and an output signal pass. Referring to FIG. 1B, a large number of leads 24 are provided along two opposing sides of the circuit board 14, but the leads 24 are arranged along one side or four sides. May be.

  The sealing resin 16 is formed by transfer molding using a thermosetting resin. In this embodiment, the sealing resin 16 is formed by a plurality of transfer moldings. In FIG. 1B, the conductive pattern 22, the semiconductor element 28, the chip element 30, and the fine metal wire 34 are sealed with the sealing resin 16. Further, the upper surface, the side surface, and the lower surface of the circuit board 14 are covered with the sealing resin 16.

  Further, referring to FIG. 1 (A), a fixing portion 19 is provided at an intermediate portion of the side surface of the sealing resin 16 facing in the left-right direction on the paper surface. The fixing portion 19 is a portion in which the side surface of the sealing resin 16 is recessed inward in a substantially semicircular shape in plan view, and a fixing means such as a screw is disposed in this portion, so that the lower surface of the sealing resin 16 Is brought into contact with a heat sink such as a heat sink.

  The sealing resin 16 will be further described with reference to FIG. First, as for the appearance of the sealing resin 16, the lower surface and side surfaces are made of the second sealing resin 20, the peripheral portion of the upper surface is made of the second sealing resin 20, and the first sealing resin 18 is exposed on the other upper surfaces. It becomes the surface to do.

  In other words, the first sealing resin 18 covers the circuit element and the circuit board 14 with the lower surface of the circuit board 14 exposed, and the second sealing resin 20 is the lower surface of the circuit board 14 and the first sealing resin. The side surfaces of 18 are sealed. The interface between the first sealing resin 18 and the second sealing resin 20 can be a path through which moisture easily enters from the outside toward the circuit board 14, but this path is set longer by this configuration, so that the moisture resistance is improved. To do.

  The first sealing resin 18 is formed by the first transfer molding, and covers the circuit elements such as the semiconductor elements 28, the connection portions of the leads 24, and the upper and side surfaces of the circuit board 14. The first sealing resin 18 is made of a thermosetting resin such as an epoxy resin filled with a filler. Further, the lower surface of the circuit board 14 is basically not covered with the first sealing resin and exposed downward. The first sealing resin 18 does not cover the lower surface of the circuit board 14 that is a path of heat generated from the semiconductor element 28. Therefore, since high heat dissipation is not required, a resin material with low heat dissipation is used as the material of the first sealing resin 18. Further, the side surface of the first sealing resin 18 led out by the lead 24 is an inclined surface in which the lead-out portion of the lead 24 protrudes to the outside in consideration of releasability during resin sealing. Here, the lower surface of the circuit board 14 is not necessarily exposed downward from the first sealing resin 18, and the first sealing resin 18 such as a thin resin burr having a thickness of about several tens of μm is used to form the circuit board 14. The lower surface may be covered.

  The second sealing resin 20 is formed by the second transfer molding, and covers the side surface and the lower surface of the first sealing resin and the lower surface of the circuit board 14. The thickness of the second sealing resin 20 is not uniform.

  Specifically, referring to FIG. 1B, the lower surface of the circuit board 14, the lower surface of the first sealing resin 18, and the side surfaces of the opposing first sealing resin 18 led out by the leads 24 are covered. 2 The thickness of the sealing resin 20 is set constant. The thickness L1 of the second sealing resin 20 that covers the lower surfaces of the circuit board 14 and the first sealing resin 18 is, for example, not less than 0.1 mm and not more than 0.3 mm. By thinning the second sealing resin 20 covering the lower surface of the circuit board 14 in this way, the thermal resistance of the second sealing resin 20 is reduced, and the heat generated from the semiconductor element 28 is reduced by the circuit board 14 and the first sealing resin 20. 2 It is discharged to the outside through the sealing resin 20 well. The thickness L2 of the second sealing resin 20 covering the side surface of the first sealing resin 18 is also approximately the same as L1.

  On the other hand, referring to FIG. 1C, the second sealing resin that covers the side surface of the first sealing resin 18 on the side surface (the side surface facing in the left-right direction in FIG. 1A) from which the lead 24 is not led out. The thickness L3 is, for example, about 5 mm, which is thicker than that in the case of FIG. This is because the fixing portion 19 shown in FIG.

  Here, in FIG. 1B, the upper surface of the first sealing resin 18 is illustrated as being exposed from the second sealing resin 20, but a thin resin burr having a thickness of about several tens of μm is illustrated. The upper surface of the first sealing resin 18 may be covered with the second sealing resin 20.

  Further, corresponding to the four corners of the circuit board 14 are provided resin protrusions 12 in which the lower surface of the first sealing resin 18 is protruded downward in a columnar shape. The width of the resin protrusion 12 is about 2.0 mm, and the height is not less than 0.1 mm and not more than 0.3 mm, similar to the second sealing resin 20 that covers the lower surface of the circuit board 14. The side surface of the resin protrusion 12 is covered with the second sealing resin 20, and the lower surface of the resin protrusion 12 is exposed downward from the second sealing resin 20 or is thinly covered with the second sealing resin 20. In this way, the lower surface of the first sealing resin 18 is partially protruded downward to form the resin protrusion 12, and the side surface of the resin protrusion 12 is covered with the second sealing resin 20. The stop resin 18 and the second sealing resin 20 fit well, and peeling of both is prevented.

  Furthermore, the distance L4 between the resin protrusion 12 and the circuit board 14 is set to 0.5 mm or more, for example. The side surface of the end portion of the circuit board 14 is a surface from which the metal material is exposed, and this portion is continuous with the outside via a boundary 36 between the first sealing resin 18 and the second sealing resin 20. Therefore, there is a possibility of short-circuiting with the outside via the boundary 36. In this embodiment, the risk of this short-circuit is reduced by separating the resin protrusion 12 from the end of the circuit board 14.

  The first sealing resin 18 and the second sealing resin 20 described above are a mixture of a resin material such as an epoxy resin, a filler, and a curing accelerator. Here, the 1st sealing resin 18 and the 2nd sealing resin 20 may be comprised from the same material, and may be comprised from a different material.

  For example, the amount of filler contained in the second sealing resin 20 may be larger than the amount of filler contained in the first sealing resin 18. Specifically, the ratio of the filler contained in the second sealing resin 20 is 83 wt% or more and 87 wt% or less (for example, 85 wt%), and the ratio of the filler contained in the first sealing resin is 78 wt% or more. 82 wt% or less (for example, 80 wt%). Since the second sealing resin 20 contains a large amount of filler, the thermal resistance is reduced, so that the heat dissipation of the second sealing resin 20 is improved. Therefore, the heat generated by the operation of the circuit element such as the semiconductor element 28 is released to the outside through the circuit board 14 and the second sealing resin 20. On the other hand, by reducing the amount of filler contained in the first sealing resin 18, the frequency with which the hard filler collides with the circuit elements and the fine metal wires 34 during resin injection is reduced. Damage to circuit elements is suppressed.

Further, the type of filler contained in the first sealing resin 18 and the type of filler contained in the second sealing resin 20 may be different. For example, alumina (Al ₂ O ₃ ) may be employed as the filler contained in the second sealing resin 20, and silica (SiO ₂ ) may be employed as the filler contained in the first sealing resin 18. By adopting alumina having excellent thermal conductivity as the filler contained in the second sealing resin 20, the effect of heat dissipation via the second sealing resin 20 is improved. Furthermore, when both resins contain alumina and silica as fillers, the proportion of alumina contained in the filler employed in the second sealing resin 20 may be greater than that of the first sealing resin 18.

  Furthermore, the amount (shrinkage rate) by which the second sealing resin 20 cures and shrinks may be larger than that of the first sealing resin 18. Specifically, the shrinkage rate associated with cure shrinkage of the first sealing resin 18 is 0.4%, and the shrinkage rate of the second sealing resin 20 is 0.5%. The shrinkage ratio of each resin can be changed by adjusting the filler content. Thereby, the compressive force accompanying the effective shrinkage of the second sealing resin 20 that wraps around the side surface and the lower surface of the first sealing resin 18 acts on the first sealing resin 18, and both are fitted at the boundary 36. Increases to prevent peeling.

  With reference to FIG. 2, the structure of the 1st sealing resin 18 and the 2nd sealing resin 20 is further demonstrated. This figure is a plan view of the hybrid integrated circuit device 10 as viewed from above, and the outer edges of the circuit board 14 and the first sealing resin 18 that are not actually seen are indicated by dotted lines.

  With reference to this figure, first, the outer edge (side) of the first sealing resin 18 is disposed between the circuit board 14 and the second sealing resin 20. Further, an intermediate portion of the side of the first sealing resin 18 facing in the left-right direction on the paper surface is disposed, for example, at an inner side of 2.0 to 3.0 mm or more from the end, whereby the concave region 13 is formed. Is formed. In addition, a part of the fixing portion 19 in which the central portion of the side surface of the second sealing resin 20 is recessed is disposed in the concave region 13.

  Under the usage condition of the hybrid integrated circuit device 10, a fixing means such as a screw is fixed to the fixing portion 19 and a stress acts. In addition, since the boundary portion between the first sealing resin 18 and the second sealing resin 20 is an interface of different materials, the mechanical strength is weaker than other portions of the sealing resin 16. Therefore, in the present embodiment, the side surface of the first sealing resin 18 is recessed inward to form the concave region 13, whereby the interface between the first sealing resin 18 and the second sealing resin 20 is fixed to the fixing portion 19. The two resins are prevented from being separated from the interface by the stress applied to the fixing portion 19. Furthermore, since the inner end portion of the fixing portion 19 is disposed in the concave region 13, there is no need to excessively enlarge the first sealing resin 18 in the left-right direction on the paper surface in order to provide the fixing portion 19. As a result, the entire apparatus is reduced in size.

  Further, the resin protrusions 12 described above are disposed on the lower surfaces of the respective corners of the first sealing resin 18.

  Next, the shape of the first sealing resin 18 will be further described with reference to FIGS. 3 and 4. 3A is a perspective view showing the first sealing resin 18, FIG. 3B is an enlarged perspective view showing a corner of the first sealing resin 18, and FIG. FIG. 4 is a cross-sectional view taken along line BB ′ in FIG. 3A, and FIG. 4B is a plan view showing the circuit board 14.

  Referring to FIGS. 3A and 4A, the four corners of the first sealing resin 18 exhibit protrusions 21 protruding in the left-right direction on the paper surface, and the upper surface of the circuit board 14 is the first sealing. An exposed portion 25 exposed from the stop resin 18 is formed. The exposed portion 25 is a portion formed by pressing and fixing the upper surface of the circuit board 14 with a mold in the step of resin-sealing the circuit board 14 with the first sealing resin 18. Therefore, in the step of forming the first sealing resin 18, the exposed portion is not formed in the first sealing resin 18 unless the circuit board 14 is pressed with a mold. Moreover, the resin projection part 12 shown in FIG.1 (C) is provided in the lower surface of each protrusion part 21. As shown in FIG.

  Referring to FIG. 3B, wall portions 23A and 23B are provided on protruding portion 21 so as to surround exposed portion 25 from both sides. Here, the height L12 of the wall portion 23B disposed on the outer side is set to be lower than the height L11 of the wall portion 23A disposed on the inner side. That is, the upper surface of the outer wall portion 23B is disposed below the upper surface of the inner wall portion 23A. This prevents the resin from reaching the concave portion where the exposed portion 25 is formed in the resin sealing step and generating voids. Specifically, the liquid resin that has flowed into the exposed portion 25 in the resin sealing step flows outwardly above the lower outer wall portion 23B. Thereby, resin spreads enough to the concave part in which the exposed part 25 was provided, and a void is prevented. The same applies to the other protrusions 21.

  With reference to FIG. 4B, exposed portions 25 where the upper surface of the circuit board 14 is exposed from the first sealing resin 18 are provided at the four corners of the circuit board 14. Specifically, the exposed portion 25 is provided in an area within a radius of 5.0 mm to 10.0 mm from the end of the circuit board 14. In this corner area, the insulating layer 26 covering the upper surface of the circuit board 14 is often cracked by pressing or dicing, so that circuit elements such as the conductive pattern 22 and the semiconductor element 28 are arranged. Absent. Therefore, even if the upper surface of the corner circuit board 14 is exposed to the outside as the exposed portion 25 from the first sealing resin 18, there is no adverse effect on the hybrid integrated circuit incorporated on the upper surface of the circuit board 14.

  As described above, in this embodiment, each surface of the circuit board 14 and the circuit element are covered with the sealing resin 16, and the sealing resin 16 includes the first sealing resin 18 and the second sealing resin 20. Yes. Therefore, the boundary 36 (FIG. 1C) between the first sealing resin 18 and the second sealing resin 20 exists inside the sealing resin 16. Therefore, if the adhesive force at the boundary 36 between the two resins is small, moisture may enter from the outside via the boundary 36 under the usage conditions.

  In this embodiment, referring to FIG. 1C, the lower surface of the first sealing resin 18 is partially protruded downward to form the resin protruding portion 12, and the side surface of the resin protruding portion 12 is second sealed. Covered with a stop resin 20. Thereby, the resin protrusion 12 of the first sealing resin 18 is embedded in the second sealing resin 20, and the adhesion strength between the first sealing resin 18 and the second sealing resin 20 is improved. Referring to FIG. 2, since the resin protrusions 12 are provided at four locations corresponding to the four corners of the circuit board 14, the effect of adhesion by the resin protrusions 12 can be obtained at each corner. .

  Further, in the present embodiment, referring to FIG. 1C, the side surface (boundary 36) of the first sealing resin 18 is an inclined surface in which the lower part extends outward from the upper part. Thereby, fitting with the 1st sealing resin 18 and the 2nd sealing resin 20 is strengthened in the boundary 36, an anchor effect occurs, and exfoliation of both resin is prevented.

  Further, in order to increase the fitting action between the first sealing resin 18 and the second sealing resin 20 at the boundary 36, the roughness of the surface of the first sealing resin 18 may be set to a certain level or more. For example, the roughness of the surface of the first sealing resin 18 is preferably 13.0 μRZ or more and 15.0 μRZ or less. This is realized by making the inner wall of the mold for molding the first sealing resin 18 into a surface having the same roughness in the resin sealing step. By setting the roughness of the surface of the first sealing resin 18 to 13 μRZ or more, the second sealing resin 20 fits well to the surface of the first sealing resin 18 at the boundary 36. In addition, by setting the surface roughness of the first sealing resin 18 to 15 μRZ or less, the first sealing resin 18 can be satisfactorily released from the mold when the first sealing resin 18 is resin-molded. be able to.

  Next, a method for manufacturing a hybrid integrated circuit device having the above-described configuration will be described with reference to FIGS. FIG. 5 shows a first transfer mold for forming the first sealing resin 18 described above, and FIG. 6 shows a second transfer mold for forming the second sealing resin 20.

  With reference to FIG. 5, first, a process of covering the circuit board 14 with the first sealing resin 18 will be described. FIG. 5A is a perspective view showing the first sealing resin 18 manufactured in this step, and FIGS. 5B and 5C are cross-sectional views showing this step in which transfer molding is performed. Here, the cross-sectional view in FIG. 5B corresponds to the line BB ′ in FIG. 5A, and the cross-sectional view in FIG. 5C corresponds to the line CC ′ in FIG. ing.

  Referring to FIG. 5B, first, a circuit board 14 having a circuit element such as a semiconductor element incorporated on its upper surface is housed in a mold 27. Specifically, a circuit element such as a semiconductor element is fixed to the upper surface of the circuit board 14, and the circuit element and the conductive pattern are electrically connected. Further, the leads 24 are fixed to the pads arranged around the circuit board 14. Thereafter, the circuit board 14 is housed in the lower mold 31 and the upper mold 29 is brought into contact with the lower mold 31 so that the circuit board 14 is housed in the cavity 39 formed as a gap between the two molds. The lead 24 is fixed by being sandwiched between the upper die 29 and the lower die 31 from above and below, whereby the position of the circuit board 14 in the cavity 39 is fixed in the thickness direction and the left-right direction. Is done. Furthermore, the lower surface of the circuit board 14 is brought into contact with the inner wall of the lower mold 31 by holding the leads 24 with the mold 27, whereby the lower surface of the circuit board 14 is covered with the first sealing resin 18 in this step. It will be exposed.

  Next, with reference to FIG. 5C, the first sealing resin 18 that has been heated to be in a liquid or semi-solid state is injected into the cavity 39. In this embodiment, referring to FIGS. 5A and 5C, a gate 42 is provided on the side where the lead 24 is not led out, and an air vent 44 is provided at a position facing the gate 42. Therefore, as the first sealing resin 18 is injected from the gate 42, the air inside the cavity 39 is released to the outside via the air vent 44.

  By injecting the first sealing resin 18 over the entire area of the cavity 39, the side and top surfaces of the circuit board 14 and circuit elements such as semiconductor elements are resin-sealed with the first sealing resin 18. On the other hand, since the lower surface of the circuit board 14 is in contact with the inner wall of the lower mold 31, it is basically not covered with the first sealing resin 18. However, when there is a gap between the lower surface of the circuit board 14 and the inner wall of the lower mold 31, the lower surface of the circuit board 14 is covered with a thin resin film made of the first sealing resin 18 that has entered the gap. .

  When the first sealing resin 18 injected into the cavity 39 is heated and cured, the upper mold 29 and the lower mold 31 are released, and the first sealing resin 18 is taken out from the mold 27. In this step, a cylindrical hole is provided in the upper mold 29, and the eject pin 38 is accommodated in this hole. The lower surface of the eject pin 38 is positioned on the same plane as the inner wall of the upper mold 29 while the first sealing resin 18 is sealed in the cavity 39. After the first sealing resin 18 is cured, When the 1 sealing resin 18 is taken out, it moves downward. As a result, the molded first sealing resin 18 is pushed out by the eject pin 38 and released. Four eject pins 38 are provided on the upper mold 29, and correspondingly, a contact portion 40 as a press mark is provided on the upper surface of the first sealing resin 18 (see FIG. 5A). .

  Referring to FIG. 5B, on the side where the lead 24 is led out, the side surface of the upper mold 29 is an inclined surface in which the lower part extends outward from the upper part, and the side surface of the lower mold 31 is lower at the upper part. It is an inclined surface that spreads outward. Since the side surfaces of both molds have such a shape, the first sealing resin molded in the cavity 39 can be easily released from the inner walls of both molds.

  On the other hand, referring to FIG. 5C, on the side where the lead 24 is not led out, the side surface of the upper mold 29 is an inclined surface in which the lower part is inclined outward from the upper part, and the lower mold 31 has a side surface. No. By doing in this way, the side surface of the 1st sealing resin 18 shape | molded becomes an inclined surface which inclines uniformly, and the anchor effect with the 2nd sealing resin formed later is acquired.

  Referring to FIG. 5C, in this step, a recess 76 is provided in which the inner wall of the lower mold 31 is partially recessed at the periphery of the circuit board 14. By injecting the first sealing resin 18 into the recess 76 in this step, the resin protrusion 12 shown in FIG. 4A is formed. The resin protrusion 12 ensures the clearance of the circuit board 14 in the next process.

  Further, in this step, a pressing portion 41 may be provided by projecting a part of the inner wall of the upper mold 29 inward, and the peripheral end portion of the circuit board 14 may be pressed by the pressing portion 41. Specifically, the peripheral end portion of the upper surface of the circuit board 14 is pressed from above at a location and shape corresponding to the exposed portion 25 shown in FIG. Thereby, the circuit board 14 is fixed in the thickness direction, and movement during resin sealing is prevented. Furthermore, since the lower surface of the circuit board 14 comes into close contact with the side wall of the lower mold 31 by the pressing force of the pressing portion 41, the first sealing resin 18 is prevented from entering the lower surface of the circuit board 14.

  Further, the inner wall of the mold 27 used in this step has a rough surface shape. Specifically, the inner wall of the mold 27 has a shape such that the surface roughness of the first sealing resin 18 is 13.0 μRZ or more and 15.0 μRZ or less. Within this range, the first sealing resin 18 can be easily released from the inner wall of the first mold 27.

  Through the above process, the first sealing resin 18 having the shape shown in FIG. 5A is formed. As described above with reference to FIG. 1, the side surface of the first sealing resin 18 from which the lead 24 is led out is an inclined surface from which an intermediate portion from which the lead 24 leads out projects outward. On the other hand, the side surface of the first sealing resin 18 from which the lead 24 is not led out is a uniform inclined surface with the upper portion inclined inward, thereby generating an anchor effect with the second sealing resin formed in the next step. Furthermore, the upper surface of the first sealing resin 18 is a flat surface, which allows the entire upper surface of the first sealing resin to be in contact with the inner wall of the mold stably in the next step.

  Referring to FIG. 6, the second transfer molding is then performed to cover the first sealing resin 18 and the circuit board 14 formed in the above process with the second sealing resin. FIG. 6A is a perspective view showing the second sealing resin 20 manufactured in this step, and FIG. 6B and FIG. 6C are cross-sectional views showing this step. 6B is a cross-sectional view corresponding to the line BB ′ in FIG. 6A, and FIG. 6C is a cross-sectional view corresponding to the line CC ′ in FIG. 6A. It is.

  In this step, first, a mold 50 including an upper mold 52 and a lower mold 54 is prepared. The cavity 56 of the mold 50 is formed slightly larger than the cavity 39 of the mold 27 used in the previous step, and the inner wall shape is the same as the shape of the resin portion shown in FIG.

  A specific sealing method is as follows. First, the circuit board 14 that is resin-sealed with the first sealing resin 18 is disposed in the lower mold 54, and the upper mold 52 is brought into contact with the lower mold 54. The circuit board 14 is accommodated in the cavity 56 to be formed. Further, the position of the circuit board 14 inside the cavity 56 is fixed by sandwiching the lead 24 between the upper mold 52 and the lower mold 54.

  In the cross section shown in FIG. 6B, the side surface of the upper mold 52 is an inclined surface whose lower part extends outward, and the side surface of the lower mold 54 is an inclined surface whose upper part extends outward. Thereby, the 2nd sealing resin 20 shape | molded by this process can be easily released from the inner wall of the metal mold | die 50 similarly to last time.

  In this cross section, the distance L1 between the lower surface of the circuit board 14 and the inner wall of the lower mold 54 is the distance L2 between the side surface of the first sealing resin 18 and the side walls of the lower mold 54 and the upper mold 52. It is the same. Specifically, the distance between L1 and L2 is, for example, in a range from 0.1 mm to 0.3 mm. By doing in this way, the 2nd sealing resin 20 inject | poured into the cavity 56 is uniformly filled under the circuit board 14 and the side of the 1st sealing resin 18, and a void is suppressed.

  In this step, referring to FIG. 6C, the position of the first sealing resin 18 inside the cavity 56 is firmly fixed by pressing the first sealing resin 18 with the mold 50. Yes. Specifically, the entire upper surface of the flat first sealing resin 18 contacts the inner wall of the upper mold 52, and the resin protrusion 12 provided on the lower surface of the first sealing resin 18 is formed on the inner wall of the lower mold 54. It is in contact. As a result, the lower surface of the circuit board 14 is separated from the inner wall of the lower mold 54 by the thickness (L1) of the resin protrusion 12.

  Next, referring to FIG. 6C, the liquid second sealing resin 20 is injected from the gate 58 into the cavity 56. The injected second sealing resin 20 is first filled in the region 56A on the left side of the first sealing resin. After the second sealing resin 20 is filled in the region 56 </ b> A, the second sealing resin 20 is filled in a narrow gap between the lower surface of the circuit board 14 and the inner wall of the lower mold 54. At the same time, referring to FIG. 6B, the second sealing resin 20 is also filled in the gap between the side surface of the first sealing resin 18 and the side walls of the lower mold 54 and the upper mold 52. . Thereafter, referring to FIG. 6C, when the second sealing resin 20 is filled in the region 56B on the right side of the first sealing resin 18 on the paper surface, the resin filling in this step is completed. Further, as the second sealing resin 20 is filled, the air in the cavity 56 is discharged to the outside via the air vent 60.

  In this step, as described above, the gap below the circuit board 14 shown in FIG. 6C and the width of the gap on the side of the first sealing resin 18 shown in FIG. 6B are set to be substantially the same. Has been. Accordingly, since the second sealing resin 20 is uniformly filled in both regions, even if the gap below the circuit board 14 is set to be narrow, for example, about 0.2 mm, the second sealing resin 20 is not voided in this region. It can be filled.

  Further, as in the previous step, the upper mold 52 used in this step is also provided with an eject pin 62, and after the filling of the second sealing resin 20 is completed, the upper surface of the first sealing resin 18 is ejected. The circuit board 14 resin-sealed with the second sealing resin 20 is taken out from the mold 50 by pressing downward with the pins 62.

DESCRIPTION OF SYMBOLS 10 Hybrid integrated circuit device 12 Resin protrusion part 13 Concave area 14 Circuit board 16 Sealing resin 18 1st sealing resin 19 Fixing part 20 2nd sealing resin 21 Protrusion part 22 Conductive pattern 23A, 23B Wall part 24 Lead 25 Exposed part 26 Insulating layer 27 Mold 28 Semiconductor element 29 Upper mold 30 Chip element 31 Lower mold 34 Metal wire 36 Boundary 38 Eject pin 39 Cavity 40 Abutting part 41 Pressing part 42 Gate 44 Air vent 50 Mold 52 Upper mold 54 Below Mold 56 Cavity 56A, 56B area 58 Gate 60 Air vent 62 Eject pin

Claims (11)

A circuit board;
Circuit elements disposed on an upper surface of the circuit board;
A first sealing resin covering the circuit element, the upper surface and the side surface of the circuit board;
A second sealing resin that covers a lower surface and a side surface of the first sealing resin,
A circuit device characterized in that the second sealing resin covers a side surface of a resin protruding portion in which a lower surface of the first sealing resin is partially protruded downward.   The circuit device according to claim 1, wherein four resin protrusions are provided near four corners of the circuit board.   The circuit device according to claim 1, wherein the resin protrusion is disposed apart from the circuit board.   4. The circuit device according to claim 1, wherein two opposing side surfaces of the first sealing resin are inclined surfaces in which an upper portion is positioned inside a lower portion. 5.   5. The circuit device according to claim 4, wherein the other two side surfaces of the first sealing resin which are opposed to each other are inclined surfaces whose intermediate portions protrude outward.   6. The circuit device according to claim 1, wherein a roughness of a surface of the first sealing resin covered with the second sealing resin is 13.0 μRZ or more.   7. The circuit according to claim 1, wherein a shrinkage rate associated with cure shrinkage of the second sealing resin is greater than a shrinkage rate associated with cure shrinkage of the first sealing resin. 8. apparatus.   8. The circuit device according to claim 1, wherein a ratio of the second sealing resin containing alumina is larger than a ratio of the first sealing resin containing alumina.   The circuit device according to claim 1, wherein the second sealing resin has a lower thermal resistance than the first sealing resin.   10. The circuit device according to claim 1, wherein a lower surface of the circuit board is exposed from the first sealing resin and is covered with the second sealing resin. 11. The circuit device according to any one of claims 1 to 10, wherein an upper surface of the first sealing resin is exposed from the second sealing resin.

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