TWI808728B - metal resin composite - Google Patents

Abstract

The metal-resin composite 1 of the present invention includes a metal plate 2 and a resin member 3 fixed to the metal plate 2. The internal space is defined by a sealing member including the resin member 3. The resin member 3 has a frame shape extending around the inner space on the metal plate 2. There are one or two welding lines 7 in the peripheral direction of the frame-shaped resin member 3. The metal plate 2 has a roughened uneven surface on the resin coating surface covered by the resin member 3. Rectangular recesses 5 a and rectangular protrusions 5 b are formed alternately in one direction and each direction perpendicular to it as viewed from below.

Description

metal resin composite

This specification discloses a technology related to a metal-resin composite body including a metal plate and a resin member fixed to the metal plate.

For metal-resin composites produced by insert molding, etc., it is required to improve the adhesion between the metal plate and the resin member.

In connection with this, for example, Patent Document 1 describes "a method of manufacturing a metal member having irregularities on the surface. The manufacturing method of the metal member includes the following steps: first punching a flat plate-shaped metal with a first punch having a first predetermined curvature and having a plurality of first protrusions in a lattice shape; performing a second punch with the first punch in a direction intersecting with the first pressing; The third stamping is performed; and the fourth stamping is performed by the second punch in a direction intersecting with the third stamping; the third stamping and the fourth stamping are performed on the parts where the first stamping and the second stamping are not performed" and "a heat sink, which has a concave-convex surface with a first concave portion and a second concave portion arranged in a grid. [Prior Art Literature] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open No. 2017-208486

However, there is a metal-resin composite in which a resin member fixed to a metal plate is further provided with another resin member, and an internal space is defined by a sealing member including the resin member. For example, in a metal-resin composite used for a semiconductor element using a metal plate as a lead frame, a semiconductor chip is enclosed in the internal space.

If the airtightness of the internal space formed by the resin member etc. is not sufficiently ensured, moisture-containing air will permeate into the internal space from the outside, and malfunctions such as malfunction of the heat-generating semiconductor chip due to contact with moisture may occur. In particular, metal-resin composites used in semiconductor devices are exposed to repeated temperature changes not only due to the opening and closing of the semiconductor chip enclosed in the internal space, but also due to changes in the external environment. From the viewpoint of further improving the airtightness of the internal space, the technique described in Patent Document 1 has room for improvement.

This specification discloses a metal-resin composite body that can improve the airtightness of an internal space formed by a resin member.

A metal-resin composite disclosed in this specification includes a metal plate and a resin member fixed to the metal plate. The internal space is divided by a sealing member including the above-mentioned resin member. The above-mentioned resin member has a frame shape extending around the inner space on the above-mentioned metal plate. There are one or two welding lines in the peripheral direction of the frame-shaped resin member. Rectangular concave portions and rectangular convex portions arranged alternately in each direction are formed.

Another metal-resin composite disclosed in this specification includes a metal plate and a resin member fixed to the metal plate. The internal space is defined by a sealing member including the resin member. The resin member has a frame shape extending around the inner space on the metal plate. There are one or two welding lines in the peripheral direction of the frame-shaped resin member. The metal plate includes a roughened plating layer on the resin coating surface covered by the resin member.

According to the above-mentioned metal-resin composite, the airtightness of the internal space formed by the resin member can be improved.

Hereinafter, embodiments of the metal-resin composite described above will be described in detail. A metal-resin composite 1 illustrated in FIG. 1 includes a metal plate 2 having a planar outer contour shape such as a rectangle, and a resin member 3 fixed to the metal plate 2 .

As shown in FIGS. 1 and 2 , the illustrated metal plate 2 has a substantially rectangular through-hole 4 penetrating in the thickness direction of the plate formed at the center. In the metal-resin composite 1, around the through-hole 4 of the metal plate 2, as an example, a frame-shaped resin member 3 having a rectangular inner and outer contour in plan view is provided, and a semiconductor chip 51 as shown in FIG. 3 is placed inside it, for example. In this case, the metal plate 2 functions as a lead frame that supports the semiconductor chip 51 and is connected to external wiring, and the metal-resin composite 1 is used for a semiconductor element. The metal plate is made of, for example, copper, aluminum or iron or alloys thereof.

The inner space of the frame-shaped resin member 3 is surrounded by sealing members such as the resin member 3 and other resin members not shown, and defines an internal space in which the semiconductor chip 51 is disposed and sealed. This metal-resin composite 1 defines an internal space in which a through hole 4 forms a part by a sealing member including a resin member 3 , and the resin member 3 is provided so as to extend around the internal space.

Furthermore, the through hole 4 provided in the metal plate 2 is not limited to the rectangle shown in the figure, and can be formed in various shapes such as a square, other polygons, or a circle according to the shape and configuration of the semiconductor chip 51 disposed therein. In addition, the outer contour shape of the metal plate 2 in plan view can also be changed to a shape other than the rectangle shown in the figure. The shape of the inner and outer contours of the frame-shaped resin member 3 in plan view may be appropriately changed to a shape other than a rectangle.

Here, the internal space divided into the metal-resin composite body 1 afterward may be required to sufficiently secure airtightness. For example, when the semiconductor chip 51 is sealed in the internal space, if the internal space is not sufficiently sealed, the air containing moisture will permeate into the internal space from the outside, which may cause malfunction of the semiconductor chip 51 .

In order to improve the airtightness of the internal space, in the present embodiment, the resin-coated surface of the metal plate 2 covered with the resin member 3 is provided with a concave-convex surface 5 as shown in FIG. 4 as an enlarged illustration. As shown in the perspective view of FIG. 5, the concave-convex surface 5 is formed by rectangular concave portions 5a and rectangular convex portions 5b, and the rectangular concave portions 5a and rectangular convex portions 5b are located at positions alternately arranged in one direction and a direction orthogonal to the one direction, that is, orthogonal directions, in a plan view of the resin coating surface. The concave-convex surface 5 presents a so-called checkered pattern in a plan view.

If the resin member 3 is provided on the metal plate 2 with the uneven surface 5 on the resin-coated surface by integral molding or the like, the passage of air from the outside to the inner space will be blocked by the uneven surface 5 . Thereby, the moisture penetration between the resin member 3 and the resin coating surface is effectively suppressed, and as a result, the airtightness of the internal space can be greatly improved.

Regarding the arrangement direction of the concave-convex surface 5, in this example, the "one direction" is defined as the direction along the long side of the rectangular metal plate 2 (the left-right direction in FIGS. 2 and 4), and the "orthogonal direction" is defined as the direction along the short side of the metal plate 2 (the up-down direction in FIGS. However, the concave-convex surface 5 can also be formed by setting the "one direction" and the "orthogonal direction" as directions inclined relative to the long side or the short side, respectively, and arranging the rectangular concave portion 5a and the rectangular convex portion 5b obliquely with respect to the long side or the short side.

The planar shape of the rectangular concave portion 5a and the rectangular convex portion 5b forming the concave-convex surface 5 may be not only a rectangle as shown in the figure, but also a square. In plan view, the size or shape of the rectangular concave portion 5a and the rectangular convex portion 5b can also be different, and the shape or size of the plurality of rectangular concave portions 5a and/or the shape or size of the plurality of rectangular convex portions 5b can also be different. As shown in FIG. 5 , the concave-convex surface 5 is formed by a rectangular concave portion 5 a and a rectangular convex portion 5 b having substantially the same shape and size in plan view.

When the rectangular concave portions 5a and rectangular convex portions 5b of the concave-convex surface 5 are respectively arranged in one direction and in an orthogonal direction, they can be considered to be alternately arranged in each direction if they are slightly misaligned in the direction orthogonal to the arrangement direction. That is, if the formation positions of the mutually adjacent rectangular concave portions 5a and the mutually adjacent rectangular convex portions 5b in one direction and each direction perpendicular to each other are inconsistent, it is considered that the rectangular concave portions 5a and the rectangular convex portions 5b are alternately arranged in each direction. For example, in the concave-convex surface 5 of FIG. 6(a), the rectangular concave portions 5a and the rectangular convex portions 5b are arranged alternately in one direction (the left-right direction in FIG. 6 ) and the orthogonal direction (the up-down direction in FIG. 6 ), and in the direction perpendicular to the arrangement direction without overlapping each other. On the other hand, in the concave-convex surface 15 of FIG. 6( b ), the rectangular concave portions 15 a and the rectangular convex portions 15 b are respectively viewed in a direction arranged in one direction, and partially overlap in a direction orthogonal to it, and are alternately arranged. However, from the viewpoint of improving the airtightness of the internal space, it is preferable to arrange the rectangular concave portions 5a and the rectangular convex portions 5b in one direction (the left-right direction in FIG. 6 ) and the orthogonal direction (the up-down direction in FIG. 6 ) respectively, as shown in FIG. The reason for this is that, thereby, there is no connection of the relatively flat rectangular protrusions 5b in the intrusion path of air from the outside to the inner space.

When the plan view shape of the rectangular concave portion 5a and the rectangular convex portion 5b is a rectangle, it is preferable that the length La of the long side of each of the rectangular concave portion 5a and the rectangular convex portion 5b is set to 0.17 mm to 0.25 mm, and the length Lb of the short side is set to 0.04 mm to 0.10 mm. If the length of the long side or the short side is too long, the number of concavities and convexities will decrease, and there is a possibility that the airtightness of the internal space will be reduced. If the length of the long side or the short side is too short, there is a concern that the risk of damage due to insufficient strength of the front end of the punch during punching will increase, and the resin entering the rectangular concave portion 5a will decrease, and the strength of the resin will decrease, resulting in a decrease in airtightness. In addition, it is preferable that the pitch Pa in the longitudinal direction of the rectangular concave portion 5a is set to 0.38 mm to 0.46 mm, and the pitch Pb in the short side direction is set to 0.11 mm to 0.17 mm. If the distances Pa and Pb are too large, the protrusions of the walls of the rectangular protrusions 5b that may be sandwiched by the adjacent rectangular recesses 5a will be insufficient, leaving a large number of flat surfaces, resulting in reduced airtightness. On the other hand, if the pitches Pa and Pb are too small, the adjacent rectangular recesses 5a may be crushed and deformed, and the strength of the resin there may decrease, resulting in a decrease in airtightness. The pitches Pa and Pb refer to the distance between the center points of the rectangular concave portions 5 a adjacent to each other via the rectangular convex portion 5 b in the one direction or the orthogonal direction.

Forming the concave-convex surface 5 formed by the rectangular concave portion 5 a and the rectangular convex portion 5 b on the resin coating surface can be performed, for example, by performing press work on the resin coating surface. In this press working, although illustration is omitted, a punch in which a plurality of protrusions having a shape corresponding to the rectangular recess 5 a are arranged in a line at the front end surface can be used.

In the case of forming the concave-convex surface 5 with a relatively small pitch Pa and/or Pb, it is preferable to perform a multiple-stage punching step including a first punching step and a second punching step. Specifically, first, as shown in FIG. 7( a ), a punch having a plurality of protrusions on the front end surface is pressed against the resin-coated surface to perform a first pressing step. Thereby, the first recessed portion group R1 is formed on the resin coating surface. Next, as shown in FIG. 7( b ), the second punching step is performed by pressing a punch having a plurality of protrusions on the front end to positions shifted in predetermined directions such as one direction and a perpendicular direction on the resin coating surface. The punches used in the second punching step can also be the same as those used in the first punching step, but can also be of different shapes. In the second pressing step, the second recess group R2 and the first recess group R1 are at least partially overlapped on the resin-coated surface, and the rectangular recesses 5a of the second recess group R2 are formed between the rectangular recesses 5a of the first recess group R1. The rectangular protrusions 5b are disposed between adjacent rectangular recesses 5a. As a result, the rectangular recesses 5a and the rectangular protrusions 5b can be densely formed on the resin coating surface.

When the concave-convex surface 5 is provided, the top surface 5c of the portion of the rectangular convex portion 5b that protrudes most on the side of the resin member 3 (the outer side in the thickness direction of the metal plate 2) may also be a flat surface, but it is preferably a curved surface that is convex on the side of the resin member 3 as shown in the cross-sectional view in the thickness direction of FIG. 8 . Thereby, the shear strength of the resin in the plan view direction is improved, and the deterioration of airtightness caused by exposure to repeated temperature changes is alleviated. Also, since there is no connection of the flat rectangular convex portion 5b in the air intrusion path from the outside to the interior space, the airtightness of the interior space can be improved. When the concave-convex surface 5 is formed using a punch provided with a plurality of protrusions on the front end surface as described above, such a rectangular convex portion 5b having a convex curved surface on the resin member 3 side may be obtained by forming a concave portion corresponding to the rectangular concave portion 5a whose walls between the rectangular concave portions 5a are convex on the outer side in the thickness direction (upper side in FIG. 8 ). Here, the depth of the rectangular recess 5 a (recess depth) is preferably 0.20 mm or less, more preferably 0.10 mm or less. If the depth of the concave portion is too large, the extension in the direction of the plate thickness will increase, and there is a possibility of deformation to an extent that affects the subsequent step (forming). The depth of the recess refers to the distance from the deepest position on the bottom surface of the rectangular recess 5a to the highest position on the top surface 5c of the rectangular protrusion 5b adjacent to the rectangular recess 5a in the thickness direction. When the rectangular recess 5a is provided, the depth of the recess is preferably from 0.02 mm to 0.20 mm, more preferably from 0.04 mm to 0.10 mm.

In order to improve the airtightness of the internal space, it is desirable that the uneven surface 5 provided on the resin-coated surface is roughened by etching or plating to increase the surface roughness Ra. Thereby, the concave-convex surface 5 becomes a roughened concave-convex surface, and the anchoring effect of the resin on the roughened concave-convex surface complements the rectangular concave portion 5a and rectangular convex portion 5b formed there, thereby greatly improving the airtightness of the internal space.

Specifically, the surface roughness Ra of the roughened concave-convex surface is preferably 0.2 μm or more. This surface roughness Ra means the arithmetic mean roughness based on JIS B0601:2001. The surface roughness Ra of the roughened concave-convex surface is the arithmetic mean roughness measured at the position of the top surface 5c of the rectangular convex portion 5b constituting the roughened concave-convex surface. Furthermore, the roughened surface of the roughened concave-convex surface can be confirmed with a stereo microscope, SEM, or laser microscope. If the roughening conditions are the same, the surface roughness of the roughened concave-convex surface is the same as that of the roughened surface without the concave-convex surface 5 . When the roughening treatment is not performed, it will become a glossy surface, and if the roughening treatment is performed, it will become a matte surface, so it may be distinguished even visually.

On the resin coating surface, instead of providing the above-mentioned concave-convex surface 5, or in addition to providing the above-mentioned concave-convex surface 5, a rough plating layer 6 may be provided as in the embodiment shown in Fig. 9 . Since the roughened plating layer 6 is provided on the resin-coated surface, the resin member 3 is sufficiently adhered to the resin-coated surface through the roughened plating layer 6 . Therefore, in this case, it is not necessarily necessary to provide the uneven surface 5 on the resin-coated surface. However, when the roughened surface 5 is provided on the resin-coated surface, and the roughened plating layer 6 is further provided thereon to form the roughened uneven surface, the airtightness of the internal space can be further improved. The presence or absence of the roughened plating layer 6 can be confirmed with an optical microscope.

The plating thickness of the roughened plating layer 6 provided on the resin-coated surface is preferably 2.0 μm to 6.0 μm, more preferably 3.0 μm to 5.0 μm. When the plating thickness of the roughened plating layer 6 is too thin, there is a concern that the adhesion of the resin member 3 to the resin-coated surface is insufficient. On the other hand, when the plating thickness of the roughening plating layer 6 is too thick, there exists a possibility of cost increase.

The rough plating layer 6 may be copper, silver, etc., but is preferably nickel-plated and may contain nickel. In the case of the roughened plating layer 6 containing nickel, there is an advantage that it is easy to control the shape and degree of roughening. In addition, at least one selected from the group consisting of nickel, copper, and silver may be contained in the rough plating layer 6 .

Forming the roughened plating layer 6 on the resin-coated surface of the metal plate 2 can be performed, for example, although not shown, by performing electroplating on the metal plate 2 in a plating solution containing the plating metal of the roughened plating layer 6 in a state where the surface of the metal plate 2 on which the roughened plating layer 6 is not formed is covered with a mask. In other embodiments, the roughened plating layer 6 may be formed on the entire surface of the metal plate 2 without using a mask.

Furthermore, part of the resin-coated surface may have a portion without the uneven surface 5 and/or the roughened plating layer 6, but from the viewpoint of sufficiently ensuring the adhesion between the resin member 3 and the metal plate 2, the uneven surface 5 and/or the roughened plated layer 6 are preferably provided on the entire resin-coated surface.

In order to install the frame-shaped resin member 3 on the metal plate 2 provided with the roughened plating layer 6 or the roughened concave-convex surface as described above, insert molding may be performed.

In the insert molding, the metal plate 2 is placed in an injection mold having a cavity corresponding to the shape of the resin member 3, and the resin material is injected from the gate of the injection mold into the cavity. The resin material flowing from the gate into the cavity flows into the cavity having a shape corresponding to the frame-shaped resin member 3 , joins in the middle, and fills the cavity. Thereafter, the resin material is cooled to solidify in the mold cavity. Thereby, the metal-resin composite 1 which fixed the resin member 3 to the metal plate 2 can be obtained.

Here, the weld line 7 is formed at the position where the resin material flowing in the cavity joins the molded resin member 3 during injection. In the illustrated embodiment, as an example, since two gates are provided at each position of the mold cavity corresponding to the central position of the two long sides of the frame-shaped resin member 3 whose inner and outer contours are rectangular in plan view, the resin material flows from each gate to the mold cavity and merges. As a result, two welding lines 7 are formed at the central position of the two short sides of the resin member 3. Alternatively, when there is one gate, one welding line 7 may be formed at a position farthest from the gate in the peripheral direction of the frame-shaped resin member 3 . The weld line 7 may be formed in a linear shape such as a straight line or a curve across the frame-shaped resin member 3 in the width direction, and can be confirmed by observing the outer surface of the resin member 3 visually or with an optical microscope.

The above-mentioned welding line 7 is preferably located at one or two locations in the peripheral direction of the frame-shaped resin member 3 . The reason for this is that, in addition to providing the above-mentioned roughened uneven surface or roughened plating layer 6 on the metal plate 2, the weld line 7 is made to be two or less, so that the airtightness of the internal space is greatly improved. In other words, if there are more than three welding lines 7 , the airtightness of the internal space will decrease, and the possibility that air containing moisture will easily penetrate from the welding lines 7 into the internal space increases.

Furthermore, the material of the resin member 3 is not particularly limited, for example, liquid crystal polymer, acrylonitrile-butadiene-styrene copolymerized resin (ABS), polyamide (PA), polypropylene (PP), polyester thermoplastic elastomer (TPC), polyacetal (POM), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), etc. can be used.

However, the illustrated metal plate 2 is provided with a plurality of notches 8 a to 8 c extending outside the through hole 4 . More specifically, in this example, there are a total of six cutouts 8a to 8c, i.e., a rectangular cutout 8a and a polygonal cutout 8b having a larger area, which are connected to the through-hole 4 on each outer side in the longitudinal direction of the rectangular metal plate 2 (in FIG. ) are connected to the through-hole 4 on each outer side, and widened outwardly to form a slightly elongated rectangle. The notches 8 a to 8 c are formed to penetrate through the metal plate 2 in the plate thickness direction.

In addition, the resin member 3 is provided not only on the front Sf side of the metal plate 2 but also on the back Sb side of the metal plate 2 as shown in FIG. Thereby, the metal plate 2 is sandwiched by the resin member 3 from both sides in a part of the peripheral direction of the frame-shaped resin member 3 , but the metal plate 2 does not exist inside the resin member 3 in the remaining part having the above-mentioned void.

In this way, when a part of the frame-shaped resin member 3 in the peripheral direction sandwiches the metal plate 2 from both sides in the plate thickness direction, it is preferable that the weld line 7 described above is formed in the peripheral direction of the frame-shaped resin member 3 and the metal plate 2 does not exist inside the resin member 3. Since the welding line 7 is present inside the resin member 3 where the metal plate 2 is not present and the resin member 3 is not supported by the metal plate 2, the airtightness of the internal space can be further improved. If the weld line 7 exists inside the resin member 3 where the metal plate 2 exists, air containing moisture may permeate into the inner space from the interface between the resin member 3 where the weld line 7 is formed and the metal plate 2 .

Furthermore, the metal plate 2 has an inner edge portion 2 a protruding from the through hole 4 side than the resin member 3 on the front surface Sf side, and is connected to the semiconductor chip 51 by a bonding wire 52 at the inner edge portion 2 a.

FIG. 11 shows a metal-resin composite 1 of another embodiment. In the metal-resin composite 1 of FIG. 11 , a protruding portion 9 protruding from the outer side of the resin member 3 is provided at a position where a weld line 7 is formed in the peripheral direction of the frame-shaped resin member 3, and has substantially the same structure as that shown in FIG. 1 except that. The protruding portion 9 protrudes from the resin member 3 in a direction substantially parallel to the surface of the metal plate 2 . Although not shown in the drawing, the protruding portion 9 may protrude from the resin member 3 in the plate thickness direction instead of protruding inside the resin member 3 (the through-hole side).

If the resin member 3 is molded using an injection molding die having a cavity provided with the protrusion 9 on the resin member 3, the flow direction of the resin material injected into the cavity will change sideways when the resin material injected into the cavity merges at the position where the protrusion 9 is formed, and the welded layer is slightly damaged. As a result, the strength of the resin member 3 is improved, and the airtightness of the internal space is also improved accordingly.

The protruding part 9 may be cut and removed thereafter. In this case, cut marks are formed and exist in the portion of the resin member 3 where the weld line 7 is formed. Cutting marks can be confirmed visually. If there is a cutting mark at the portion of the resin member 3 where the welded line 7 is formed, it can be inferred that the protruding portion 9 was formed there before, thereby reinforcing the weak portion caused by the welded line 7 . [Example]

Next, the above-mentioned metal-resin composite was tried to be produced, and its effect was confirmed, so it will be explained as follows. However, the description here is for the purpose of illustration only, and is not intended to be limited thereto.

(uneven surface) Fabricate the metal-resin composite as shown in Figure 1. In Examples 1 to 4 and Comparative Examples 3 and 4, as explained using FIG. 6 , the first punching step and the second punching step were performed on the resin-coated surface of the metal plate using each punch provided with a plurality of protrusions on the front end surface, forming rectangular rectangular concave portions and rectangular convex portions alternately arranged in one direction and each direction perpendicular to the direction thereof, and providing a concave-convex surface (rectangular concave-convex surface). The length La of the long side of each rectangular recess was set to 0.21 mm, the length Lb of the short side was set to 0.07 mm, the distance Pa between the long sides was set to 0.42 mm, and the distance Pb between the short sides was set to 0.14 mm. The plan view dimensions of the rectangular concave portion and the rectangular convex portion are set to be substantially the same. The depth of the rectangular recess (deep depth) is shown in Table 1.

In Comparative Example 2, the resin-coated surface of the metal plate is provided with a concave-convex surface (linear concave-convex surface) in which a plurality of linear concave portions extending in one direction are formed at intervals in a direction perpendicular to the linear direction. The width of the linear recesses is set to 0.04 mm, and the distance between the linear recesses is set to 0.1 mm. A linear convex portion is formed between adjacent linear concave portions.

In Examples 5 and 6 and Comparative Examples 1 and 5, no concavo-convex surface was provided on the resin-coated surface of the metal plate.

(surface treatment) In Examples 1 and 2 and Comparative Examples 2 and 4, roughening treatment (etching) was performed on the resin-coated surface or uneven surface using CZ-8101 manufactured by MEC Co., Ltd. at a treatment temperature of 30°C so that the surface roughness Ra shown in Table 1 was obtained.

In Examples 3-6 and Comparative Example 5, roughening nickel plating was given to the resin coating surface of a metal plate. Plating bath composition: Ni metal component 130 g/L, boric acid 25 g/L, pH value 3.3. Here, the Ni metal component is composed of nickel sulfamate tetrahydrate and Ni chloride which are Ni salts. More specifically, nickel sulfamate tetrahydrate: Ni(NH ₂ SO ₃ ) ₂ 4H ₂ O = 294 g/L (about 300 g/L), 53.5 g/L in Ni amount, nickel chloride hexahydrate: NiCl ₂ 6H ₂ O = about 310 g/L, 76.5 g/L in Ni amount. The temperature of the plating solution was set at 60° C., and the current density was set at 10 A/dm ² . The processing time was adjusted so that the surface roughness Ra of Table 1 was obtained.

In Comparative Examples 1 and 3, no surface treatment was performed on the resin-coated surface of the metal plate.

In addition, the measurement of the surface roughness Ra shown in Table 1 was carried out with a non-contact surface texture measuring device (PF-60) manufactured by Mitaka Koki Co., Ltd., and in the case of a roughened uneven surface with an uneven surface, the position of the top surface of the rectangular convex portion or the linear convex portion was observed. The observation magnification is set to 1000 times, and the spot diameter is set to 1.0 μm, the resolution is set to 0.1 μmm on the X axis, 0.1 μmm on the Y axis, and 0.01 μm on the Z1 axis (Z axis for measurement). Measurement settings are as follows. Measuring pitch: 1 μm Measuring range: 8.0 mm (scanning on a straight line) (In the case of measuring the convex part of the concave-convex surface, the part is extracted from the back) Measuring accuracy: X-axis 2 μm, Y-axis 2 μm, Z1-axis 0.3 μm Measuring method: scanning Scanning speed: 100 μm/s AF gain: Standard Objective lens: SL100× (100 times)

(injection molding) The resin material is a liquid crystal polymer (M-350B manufactured by ENEOS Liquid Crystal Co., Ltd.), and the resin member is fixed to a metal plate by insert molding using an injection mold. In any of the Examples and Comparative Examples, the injection pressure was 150 MPa, and the sprue sleeve temperature was 360° C. except for Comparative Example 5. In Comparative Example 5, the sprue sleeve temperature was set to 170°C.

In Examples 1 to 6 and Comparative Examples 1 and 3, two gates are provided in the peripheral direction of the cavity of the injection molding mold, thereby forming two weld lines in the peripheral direction of the resin member at the portion where no metal plate exists. In Comparative Examples 2, 4, and 5, since four gates were provided, the weld lines formed in the resin member were four in the circumferential direction. In Example 2, two protrusions as shown in FIG. 11 were provided in the position where the weld line was formed on the resin member.

(red check test) Conduct a red inspection test on the metal-resin composite to verify whether the red test liquid penetrates between the resin component and the metal plate. Specifically, around the through-hole of the metal plate of the metal-resin composite, a small amount of the test solution was applied to the inner edge of the resin member with the tip of a wire, and left for 0.5 hours. If the test liquid does not leak outside the resin member after being left to stand, the test liquid has not permeated the resin member, so it can be evaluated that the airtightness is good.

The test was carried out on the unheated metal-resin composite and the metal-resin composite heated at 260°C for 2 hours. In Examples 1-6 and Comparative Examples 2 and 4, five metal-resin composites without heating and five metal-resin composites after heating were used for the test. In Comparative Examples 1, 3, and 5, a test was performed on one non-heated metal-resin composite. Table 1 shows the ratio (n/5 or n/1) of the number (n pieces) that did not leak the test solution to the total number (5 pieces or 1 piece) used for the test.

(Resin peel test) Using a block jig, force is applied from the outside to the inside of the resin member of the metal-resin composite in a direction horizontal to the metal plate to peel the resin member from the metal plate. After peeling off the resin member, the residue of resin adhering to the metal plate is checked. Resin remaining on the metal plate means that the form of peeling is not the form of peeling from the interface between the metal plate and the resin member, but the form produced by the cohesion failure inside the resin member. It can be judged that the adhesion between the metal plate and the resin member is good. The punch block of the block fixture is set to the size of width 8.3 mm x thickness 1.8 mm x length 26.0 mm. The resin peeling test was also carried out on the non-heated metal-resin composite and the metal-resin composite after heating (260°C, 2 hours).

The results are shown in Table 1. Here, the case where the resin residue is less than 10% of the area of the resin coating surface is marked as "×", the case where the resin residue is more than 10% and less than 50% of the area of the resin coating surface or the case where the resin residue is intermittent and the inside and the outside are connected is marked as "△", and the case where the resin residue is more than 50% of the area of the resin coating surface and the inside and outside are blocked by the resin residue is marked as "○".

(Thermal cycle test) For each of the metal-resin composites of Examples 1-6, as shown in FIG. 12 , the lids 81a, 81b were bonded to both sides of the resin member 73 of the metal-resin composite 71 with an adhesive 82 to produce a test object 91 simulating a semiconductor element. However, the test object 91 does not have a semiconductor chip in the inner cavity. The resin member 73 and the covers 81 a and 81 b are made of a liquid crystal polymer (M-350B manufactured by ENEOS Liquid Crystal Co., Ltd.).

After subjecting the above-mentioned test body 91 to a heat cycle test in which the temperature was repeatedly raised and lowered from -65°C to 160°C, the test body 91 was immersed in water to check for air leakage. The results are shown in Table 1. In Table 1, the ratio of the number of test objects 91 without air leakage to the total number of test objects 91 used in the test is disclosed for each of the cases where the heat cycle test was performed 100 times, 200 times, and 500 times.

(Tightness evaluation) The airtightness of the internal space of the metal-resin composite was evaluated based on the results of the above-mentioned red color test, resin peeling test, and heat cycle test. The results are shown in Table 1. In Table 1, regarding the airtightness, "○" indicates that the airtightness is good, "△" indicates that the airtightness is to some extent, and "×" indicates that the airtightness is insufficient.

[Table 1] Resin coating Recess Depth (mm) surface treatment Surface roughness Ra (μm) weld line With or without protrusion Non-heated red check Red check after heating Resin peeling before heating Resin peeling off after heating Thermal cycle (100 times) Thermal cycle (200 times) Thermal cycle (500 times) Closeness Example 1 Rectangular concave-convex surface 0.067 etching 0.50 2 none 5/5 5/5 ○ ○ 6/6 - 5/6 △ Example 2 Rectangular concave-convex surface 0.067 etching 0.50 2 have 5/5 5/5 ○ ○ 6/6 - 6/6 ○ Example 3 Rectangular concave-convex surface 0.067 Rough Ni plating 0.29 2 none 5/5 5/5 ○ ○ 5/5 5/5 - ○ Example 4 Rectangular concave-convex surface 0.067 Rough Ni plating 0.25 2 none 5/5 5/5 ○ ○ 5/5 5/5 - ○ Example 5 No uneven surface - Rough Ni plating 0.27 2 none 5/5 5/5 ○ ○ 5/5 5/5 - ○ Example 6 No uneven surface - Rough Ni plating 0.25 2 none 5/5 5/5 ○ ○ 5/5 4/5 - △ Comparative example 1 No uneven surface - - 0.10 2 none 0/1 - - - - - - x Comparative example 2 linear concave-convex surface 0.067 etching 0.50 4 none 5/5 5/5 △ △ - - - x Comparative example 3 Rectangular concave-convex surface 0.067 - 0.10 2 none 0/1 - - - - - - x Comparative example 4 Rectangular concave-convex surface 0.067 etching 0.50 4 none 5/5 5/5 △ △ - - - x Comparative Example 5 No uneven surface - Rough Ni plating 0.30 4 none 0/1 - - - - - - x

(discuss) As shown in Table 1, it can be seen that in Examples 1 to 6, compared with Comparative Examples 1 to 5, the airtightness of the internal space is higher than that of Comparative Examples 1 to 5 by setting the weld line of the resin member at two or less places and providing a roughened uneven surface or a roughened plating layer on the resin coating surface. Not only in Examples 1 to 4 in which the rectangular uneven surface was formed by etching or roughening plating, but also in Examples 5 and 6 in which roughening plating was performed on the resin-coated surface without forming an uneven surface, high airtightness of the internal space was ensured.

On the other hand, in Comparative Example 1, since neither the uneven surface nor the roughened plating layer was provided on the resin coating surface, the airtightness was low. As can be seen from Comparative Example 3, even if a rectangular concave-convex surface is provided on the resin-coated surface, sufficient airtightness cannot be ensured without roughening treatment. In addition, from Comparative Examples 2, 4, and 5, it can be seen that when the number of weld lines formed in the resin member increases, the airtightness decreases.

From the above, it can be seen that according to the above-mentioned metal-resin composite, the airtightness of the internal space formed by the resin member can be improved.

(resin adhesion) The resin member was fixed to the nickel-plated copper metal plate and the copper metal plate without any treatment, and then the resin member was peeled off to measure the shear strength. The results are shown in Table 2.

[Table 2] deal with Plating thickness (μm) Rz (μm) Shear strength (MPa) Ni-plated metal plate Ni plating 0.5 0.962 4.574 Metal plate none - 0.928 18.423

It can be seen from Table 2 that although the surface roughness Rz of the resin-coated surface is approximately the same, the untreated metal plate has a higher shear strength. This surface roughness Rz means the maximum height based on JIS B0601:2001. Also, it is known that the resin adhesion of nickel plating is generally low. Furthermore, the measurement of the surface roughness Rz is carried out by means of a laser microscope (VK-X150) manufactured by Enns Corporation. The observation magnification is 1000 times, and the spot diameter is Measured under the condition of 0.8 mm. The objective lens is set at 100 times. The measurement range (measurement area) was set to the size of an image obtained after measurement with the laser microscope, that is, 105.737 μm×141.029 μm. The analysis is performed by drawing horizontal lines (vertical lines) in line roughness measurement and performing calculations.

Therefore, even when a rough nickel plating layer with low resin adhesion is provided on the resin coating surface, sufficient airtightness of the internal space can be ensured as shown in Table 1, so it can be said that high airtightness can also be exhibited when a rough plating layer other than nickel is provided on the resin coating surface.

1,71: metal resin composite 2,72: metal plate 2a: inner edge 3,73: Resin components 4: Through hole 5,15: concave and convex surface 5a, 15a: Rectangular recess 5b, 15b: rectangular convex part 5c: top surface 6: Coarse plating layer 7: Weld line 8a～8c: Incision part 9: Projection 51: Semiconductor wafer 52: Bonding wire 81a, 81b: cover body 82: Adhesive 91: Subject for test La: The length of the long side of the rectangular concave part and the rectangular convex part Lb: The length of the short side of the rectangular concave part and the rectangular convex part Pa: The pitch in the long side direction of the rectangular recess Pb: Pitch in the short side direction of the rectangular recess R1: the first recess group R2: Second recess group Sb: back Sf: front

[ Fig. 1 ] is a plan view showing a metal-resin composite according to an embodiment. [ Fig. 2 ] is a plan view showing a metal plate included in the metal-resin composite of Fig. 1 . [ Fig. 3] Fig. 3 is a plan view showing the metal-resin composite in Fig. 1 in a state where a semiconductor chip is mounted. [ Fig. 4 ] is a partially enlarged plan view showing the metal plate in Fig. 2 . [ Fig. 5 ] is a perspective view showing a part of the concave-convex surface of the metal plate in Fig. 2 . [ Fig. 6 ] is a plan view showing the concave-convex surface of the metal plate in Fig. 2 and its modification. [FIG. 7] It is a top view which shows the example of the formation of the uneven|corrugated surface on the resin-coated surface of a metal plate. [ Fig. 8 ] is a sectional view taken along line VII-VII of Fig. 6( a ). [ Fig. 9 ] is a plan view showing a metal plate included in a metal-resin composite according to another embodiment. [ Fig. 10 ] is a bottom view showing the metal-resin composite in Fig. 1 . [ Fig. 11 ] is a plan view showing a metal-resin composite in still another embodiment. [ Fig. 12 ] is a cross-sectional view and a plan view showing a test object manufactured using a metal-resin composite in Examples.

Claims (8)

A metal-resin composite body comprising a metal plate and a resin member fixed to the metal plate. The inner space is defined by a sealing member including the resin member. The resin member has a frame shape extending around the inner space on the metal plate. There are one or two welding lines in the peripheral direction of the frame-shaped resin member. The metal plate has a roughened concave-convex surface on the resin coating surface covered by the resin component. Rectangular recesses and rectangular protrusions arranged alternately in directions are formed. The metal-resin composite according to claim 1, wherein the surface roughness Ra of the roughened concave-convex surface is 0.2 μm or more. The metal-resin composite according to claim 1 or 2, wherein each of the rectangular concave portion and the rectangular convex portion is rectangular in plan view of the resin-coated surface. The metal-resin composite according to claim 1 or 2, wherein the rectangular protrusion has a convex curved surface on the side of the resin member. The metal-resin composite according to claim 1 or 2, wherein a portion of the frame-shaped resin member in the peripheral direction sandwiches the metal plate from both sides in the plate thickness direction, and the weld line is formed at a portion of the frame-shaped resin member in the peripheral direction where the metal plate does not exist inside the resin member. A metal-resin composite body comprising a metal plate and a resin member fixed to the metal plate, the inner space is defined by a sealing member including the resin member, the resin member has a frame shape extending around the metal plate surrounding the inner space, one or two welding lines exist in the peripheral direction of the frame-shaped resin member, the metal plate has a roughened plating layer on the resin-coated surface covered by the resin member, and the frame-shaped resin member sandwiches the metal plate from both sides in the thickness direction of the frame-shaped resin member Furthermore, the welding line is formed at a portion in the peripheral direction of the frame-shaped resin member where the metal plate does not exist inside the resin member. The metal-resin composite according to claim 6, wherein the roughened plating layer contains nickel. The metal-resin composite according to claim 1, 2, 6, or 7, wherein there are cutting marks at the portion where the weld line is formed on the resin member.