JP6278297B2 - Junction structure and semiconductor device using the same - Google Patents

Description

  The present invention relates to a junction structure and a semiconductor device using the junction structure.

  In order to join a plurality of members, various joining techniques such as soldering and an adhesive have been conventionally applied. In such a joining technique, as described in Patent Literature 1 and Patent Literature 2, a plurality of small structures having a spiral shape or the like are provided on the joining surfaces of the members, A technique for joining a plurality of members by contact or contact between this structure and another structure is also known.

  In the technique described in Patent Document 1, a large number of spiral contact conductors having a length of 5 mm are erected on the surface of a copper sheet having a width of 20 mm and a length of 50 mm, and these contact conductors are entangled to form a copper sheet. Join each other.

  In the technique described in Patent Document 2, a plurality of buffer materials having a spiral structure or a lattice structure made of Au or Al wire having a diameter of 20 to 50 μm are randomly arranged inside the adhesive on a circuit mounting substrate to which a semiconductor element is attached. A conductive elastic body is provided. By inserting metal bumps provided on the semiconductor element into the conductive elastic body, the semiconductor element and the circuit mounting substrate are joined.

  According to the techniques described in Patent Document 1 and Patent Document 2 described above, the reliability of electrical, mechanical, or thermal connection is improved.

JP 2003-299506 A (paragraphs 0016 and 0020, FIG. 3) JP 2006-287091 A (paragraphs 0036 and 0040, FIGS. 1 and 2)

  When a load or displacement acts on a joining structure that joins different members, there is a problem of preventing breakage of the joint portion disposed between the members to be joined and preventing separation of the interface between the member to be joined and the joint portion. For this reason, a bonded structure having a high strength at the bonded portion itself or at the interface is desired.

  In particular, in an apparatus using a combination of members made of different materials such as a power semiconductor device, thermal stress is inevitably generated. In addition, thermal stress is increasing with the miniaturization and high density of the device, and this trend is in the future. For this reason, in such an apparatus, the above problem is more remarkable.

  On the other hand, in the above-described conventional technology, it is difficult to significantly improve the strength of the bonding layer and the member interface.

  Therefore, the present invention provides a bonding structure that can greatly improve the strength of the bonding layer and the member interface when bonding a plurality of members, and a semiconductor device using the bonding structure.

  In order to solve the above-described problem, in the joining structure according to the present invention, a spring-like nanostructure having a shape dimension of less than 1 μm, that is, a nano-order scale, is provided at a joint between joined members.

  One embodiment of the present invention as described above is a joint structure including a first member, a second member, and a joint portion that joins the first member and the second member. The junction includes a plurality of spring-like nanostructures.

  The first and second members may be conductors, semiconductors, or insulators. For the spring-like nanostructure, a conductive material such as a metal material or an insulating material such as a ceramic material can be used. The spring shape may be, for example, a spiral shape, that is, a coil shape, a multi-line shape having a plurality of linear portions connected to each other, or a polygonal line shape.

  Furthermore, the joining structure according to the present invention can be applied to joining a lead frame and a heat dissipation base and joining a lead frame and a sealing resin in a semiconductor device.

  According to the present invention, the strength of the nanostructure itself is higher than that of the bulk material, and a large number of nanostructures can be arranged on the joint surface. The mechanical strength of the interface is greatly improved. As a result, the reliability of bonding is greatly improved.

  Problems, configurations, and effects other than those described above will become apparent from the following description of embodiments.

1 is a schematic cross-sectional view of a semiconductor device according to a first embodiment. Indicates the failure mode of the joint. Indicates the failure mode of the joint. Indicates the failure mode of the joint. The manufacturing method of the junction structure of a 1st Example is shown. The manufacturing method of the junction structure of a 1st Example is shown. The manufacturing method of the junction structure of a 1st Example is shown. The manufacturing method of the junction structure of a 1st Example is shown. The manufacturing method of the junction structure of a 1st Example is shown. The manufacturing method of the junction structure of a 1st Example is shown. It is the upper surface photograph and cross-sectional photograph of a spring layer. It is a schematic diagram of an indenter indentation test device for a spring layer. The measurement result of an indenter indentation test is shown. The measurement result of an indenter indentation test is shown. The measurement result of an indenter indentation test is shown. It is a cross-sectional schematic diagram of the junction structure which is a 2nd Example. The properties of the joint structure are shown. It is a cross-sectional schematic diagram of the junction structure which is a 3rd Example. It is a cross-sectional photograph of a multi-linear spring layer. The manufacturing method of the junction structure of the 4th example is shown. The manufacturing method of the junction structure of the 4th example is shown. The manufacturing method of the junction structure of the 4th example is shown. The simulation result of the deformation behavior of a bilinear spring is shown. The simulation result of the deformation behavior of a trilinear spring is shown. It is a cross-sectional schematic diagram of the junction structure which is a 5th Example. It is a cross-sectional schematic diagram of the junction structure which is a 5th Example. It is a cross-sectional schematic diagram of the junction structure which is a 5th Example. It is a cross-sectional schematic diagram of the junction structure which is a 6th Example. It is a cross-sectional schematic diagram of the junction structure which is a 7th Example. It is a cross-sectional schematic diagram of the semiconductor device which is an 8th Example.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic sectional view of a semiconductor device according to a first embodiment of the present invention.

  In this embodiment, the semiconductor element 1 is joined to a lead frame 3 made of a metal material via a solder 2, and the lead frame 3 and a heat dissipation base 5 made of a metal material are joined via a joint portion including an insulating layer 4. Has been. In addition to these members, wires for electrically connecting the terminals provided on the upper surface of the semiconductor element 1 and the lead frame, a sealing material for sealing the entire semiconductor device, and the semiconductor device and the external circuit are electrically connected. An electrode terminal or the like for connection is provided, but is omitted in FIG.

  In this embodiment, an IGBT (Insulated Gate Bipolar Transistor) formed on a silicon chip having a side of about 10 mm and a thickness of about 0.1 mm is used as the semiconductor element 1. The IGBT is known as a typical power semiconductor device.

  The lead frame 3 uses copper having a thickness of about 0.5 mm to reduce thermal resistance and electrical resistance, and the heat radiating base 5 uses aluminum to reduce the weight while ensuring heat dissipation. At this time, in the insulating layer 4, the spring layer 4a provided on the surface of the lead frame 3 and the spring layer 4b provided on the surface of the heat radiating base 5 are mechanically entangled and fitted, and the lead frame 3 including the spring layer A space between the heat dissipation bases 5 is filled with a resin 4c as a filling member.

  In the spring layers 4a and 4b, a plurality of or many nanostructures having a spring shape (hereinafter simply referred to as springs) are arranged. In this embodiment, coiled springs are arranged. Here, the nanostructure is a structure whose geometric dimension is nanoscale smaller than 1 μm.

  In this embodiment, the spring layer 4a provided on the surface of the lead frame 3 and the spring layer 4b provided on the surface of the heat radiating base 5 are respectively constituted by springs made of silicon nitride, that is, ceramics, and epoxy resin is used for the resin 4c. Thus, electrical insulation between the lead frame 3 and the heat dissipation base 5 is ensured. Moreover, the thickness of the insulating layer 4 shall be 10-100 micrometers according to the insulation performance requested | required. In the spring layers 4a and 4b, coiled springs are densely arranged. Each spring has a wire diameter of about 40 nm, a coil outer diameter of about 120 nm, and a coil pitch of about 150 nm, and the wire diameter and the coil outer diameter are larger as the position is away from the lead frame 3 and the heat dissipation base 5 in the vertical direction. Become.

  In this embodiment, since the lead frame 3 is made of copper and the heat dissipation base 5 is made of aluminum, the insulating layer 4 is joined with materials having different linear expansion coefficients. For this reason, when the temperature of the semiconductor device changes due to the operation heat generation of the semiconductor element 1 or the change in the use environment temperature, a difference occurs in the thermal deformation of the lead frame 3 and the heat dissipation base 5. . In this embodiment, since the insulating layer 4 is composed of the resin 4c and the spring layers 4a and 4b made of a low-elasticity nanostructure, the insulating layer 4 has a reduced elastic modulus and can reliably absorb deformation.

  In this embodiment, since the material of the nanostructures of the spring layers 4a and 4b is silicon nitride having a high insulating property, the spring layer 4a provided on the surface of the lead frame 3 and the spring layer 4b provided on the surface of the heat dissipation base are fitted. Even if they are contacted or adjacent to each other, electrical insulation between the lead frame 3 and the heat dissipation base 5 can be ensured.

  FIG. 2 shows a typical failure mode of the joint.

  2A is a mode in which the interface of the bonded portion is peeled off, FIG. 2B is a mode in which a crack propagates inside the bonding layer, and FIG. 2C is a mode in which the interface between the spring and the filling resin is peeled off. is there.

In this embodiment, since the coil pitch is about 150 nm, the number of springs arranged per unit area (1 mm ² ) on the surface of the lead frame 3 and the surface of the heat dissipation base 5 is about 4 × 10 ⁷ . Since the wire diameter is about 40 nm, the area of the spring per unit area (1 mm ² ) of the interface is π × (20 × 10 ⁻⁶ ) ² × 4 × 10 ⁷ = 0.05 mm ² , that is, 5% of the total area. It is. The strength of the bulk material of silicon nitride is generally about 700 MPa or more. Furthermore, since the material constituting the spring of the nanospring layer is a nanoscale structure, dislocations are unlikely to occur inside the crystal, and yield stress and strength are more than double that of the bulk material as shown in the test results described later. large. From this, when the strength of the spring is 1400 MPa, which is twice that of the bulk material, the strength of the interface is 70%, which is 5% of 1400 MPa. This is several times larger than the strength of the epoxy resin used for the resin 4c. From this, in the joining structure of the present embodiment, it is higher than the joining structure having no spring layer as compared with the mode in which the interface between the joined member and the joining portion as shown in FIG. Reliability is obtained.

  In this embodiment, since the spring layer 4a provided on the surface of the lead frame 3 and the spring layer 4b provided on the surface of the heat dissipation base 5 are fitted, at least the lead is required when the insulating layer 4 breaks. Either the spring layer 4a provided on the surface of the frame 3 or the spring layer 4b provided on the surface of the heat dissipation base 5 is disconnected. Therefore, the breaking strength of the joint including the joining layer 4 is at least equivalent to the strength of the spring layer.

  As described above, the strength of the spring layer is several times greater than the strength of the epoxy resin used as the filling resin. From this, in the joining structure of the present embodiment, high reliability can be obtained even for the mode in which the crack propagates inside the joint as shown in FIG.

  In this embodiment, since the springs can be arranged closely, a very large number of nanosprings can be arranged per unit surface volume of the member to be joined. As a result, the joint area between the filling resin and the spring having a three-dimensional shape is increased. Since the stress at the interface between the spring and the filling resin is a value obtained by dividing the load applied to the interface by the bonding area, the stress at the interface can be greatly reduced in this embodiment having a large bonding area. For this reason, in the joining structure of a present Example, high reliability is acquired also with respect to the mode in which the interface of a spring and filling resin peels as shown in FIG.2 (c).

  By the way, in the macro-scale joining structure, the stress is remarkably larger in the vicinity of the joining end portion than in other regions. This is because the stress distribution at the joint end becomes a singular stress singular field, and the stress is theoretically infinite at the joint end of the dissimilar material. In general, this stress singularity appears in the region of several tens to several hundreds of nm or more from the joint end. However, in the spring layer used in this embodiment, nano-order structures are densely arranged, and a plurality of structures are also arranged in a region that becomes a singular field on a macro scale. For this reason, the stress singularity does not appear remarkably at the end of the spring layer, and an increase in stress at the joined end can be prevented.

  As described above, according to the joint structure of the present embodiment, high reliability can be obtained for any failure mode of the joint portion. That is, the strength of the joint itself and the interface between the joint and the member to be joined can be greatly improved.

  Next, FIGS. 3A to 3C and FIGS. 4A to 4C show a method for manufacturing the joint structure of this embodiment. In this production method, for example, known nanostructures described in the literature, Takayuki Kitamura, et al, “FRACTURE NANOMECHANICS”, PAN STANFORD PUBLISHING (2011), ISBN 978-981-4241-83-0. The body manufacturing method is used.

  First, as shown in FIG. 3B, the surface layer 22 is formed on the surface of the member 21 to be joined as shown in FIG. The surface layer 22 enhances the bondability between the member to be bonded 21 and the spring formed in the next process, and adjusts the surface roughness of the member to be bonded 21 to make it flat. Next, as illustrated in FIG. 3C, vapor deposition atoms 23 are deposited on the surface of the bonded member 21 on which the spring layer is formed by a vacuum vapor deposition method from an oblique direction. At this time, by depositing the vapor deposition atoms 23 while rotating the member 21 to be bonded, the atoms are deposited in a coil shape, and a coiled spring layer 24 that adheres to or adheres to the surface of the member 21 to be bonded is formed. The spring is erected on the surface of the member to be bonded 21 so that the length direction thereof is perpendicular to the surface of the member 21 to be bonded.

  Next, as shown to Fig.4 (a), the to-be-joined member 21 and the to-be-joined member 31 are arrange | positioned so that the surface in which each nanospring layer was formed may face. Next, as shown in FIG. 4B, a spring layer 24 provided on the surface of the member 21 to be bonded and a spring layer provided on the surface of the member 31 to be bonded by pressing the bonding member 21 and the member 31 to be bonded. 32 is mechanically fitted. Thereby, both to-be-joined members are joined and positioned mutually. At this time, depending on the shape of the spring, when the member to be bonded 21 and the member to be bonded 31 are pressed, vibration is applied with ultrasonic waves or the like, so that the spring layers are more easily fitted. Next, as shown in FIG. 4C, the member to be bonded 21 and the member to be bonded 31 are more firmly bonded by filling the resin 33 between the fitted springs.

  At this time, since the member to be bonded 21 and the member to be bonded 31 are bonded by the fitting of the nanospring, they can be bonded without being filled with the resin 33. In this case, the repair can be performed without damaging the member to be joined and the spring layer. It should be noted that the presence or absence of the resin 33 can be appropriately selected according to the use of the bonding structure.

  The mechanical characteristics of the spring layer will be described with reference to FIGS.

  FIG. 5 is a top view photograph and a sectional photograph of a spring layer in which Ni nano-order coils are densely arranged. Each spring has a wire diameter of about 40 nm, a coil outer diameter of about 120 nm, a coil pitch of about 150 nm, and a height of about 400 nm. The inventor has pushed the indenter into the nanospring layer, and studied the mechanical characteristics of the nanospring layer from the relationship between the load and the displacement at that time.

  FIG. 6 shows a schematic diagram of a nanospring layer indenter indentation test apparatus. The load-displacement relationship was obtained when a conical indenter with a radius of curvature of 10.44 μm was pushed into the spring layer using a device incorporating a Hysitron Triboscope capable of controlling a minute load of 10 μN to 10 mN in an atomic force microscope. . The displacement measurement resolution is 0.2 nm. Measurement is performed by load control. When the same load is applied twice and the load-displacement relationship does not change, the elastic deformation range is determined, and then the load is increased at the same position and the same load is applied twice again. Repeated that. By repeating this procedure, the yielding load and the displacement at that time were obtained.

  7A to 7C show the measurement results. The vertical axis is the load, and the horizontal axis is the displacement. Under the conditions of a load of 19.0 μN (FIG. 7A) and 20.2 μN (FIG. 7B), no change was observed in the first-second load-displacement relationship, and the elastic deformation range. On the other hand, under the condition of a load of 22.0 μN (FIG. 7C), it can be determined that the first-second load-displacement relationship has changed and the yield has been increased by applying the first load. When this test was performed three times at different measurement positions, the yielded loads were 21.9 μN, 15.2 μN, and 10.6 μN, and the displacements for these loads were 21.7 nm, 24.6 nm, and 20 respectively. .8 nm. The average values are 15.9 μN and 22.4 nm, respectively.

  The shear stress τ generated when the coil spring is compressed by the displacement u is generally expressed by the following equation (1).

  Here, G is a transverse elastic modulus, d is a wire diameter, n is an effective number of turns, and D is an average coil diameter. By substituting the physical property value and dimensions of the spring of the nanostructure into equation (1) and substituting the average value of 22.4 nm of displacement at which plastic deformation occurs for displacement u, the shear stress τ at which plastic deformation occurs is 759 MPa. It is 1.32 GPa when converted to Mises equivalent stress. This value is the yield stress of the material constituting the spring, which is twice or more larger than the yield stress of the Ni bulk material. The reason why the yield stress is larger than that of the bulk material is that dislocations from the surface are difficult to enter in the nanoscale structure.

  FIG. 8 is a schematic cross-sectional view of a joint structure according to the second embodiment of the present invention. Unlike the first embodiment, the spring layer 24 provided on the surface of the member 21 to be joined and the spring layer 32 provided on the surface of the member 31 to be joined are not mechanically fitted to each other. The members 21 and 31 are separated from each other in a direction perpendicular to the bonding surface, and the bonded members 21 and 31 are bonded by the resin 33.

  In the present embodiment, the spring layers are not fitted to each other, but the joining layer includes the spring layer, whereby the interface between the joined member and the joining portion shown in FIG. The reliability of the mode shown in c) in which the interface between the spring and the resin peels is improved. When joining a member to be joined by resin, in general, the strength against the mode in which the interface shown in FIGS. 2A and 2C peels is higher than the mode in which a crack propagates inside the resin shown in FIG. Get smaller. Therefore, by applying the present embodiment to the bonding layer using a resin, the reliability of the two modes of FIGS. 2A and 2C is improved, and the reliability of the bonding can be improved.

  FIG. 9 summarizes the properties of a known joining structure having no spring, a joining structure having a millimeter-order surface fastener having a spring, and each joining structure according to the first and second embodiments of the present invention. Show.

  A known joint structure having no spring is composed only of a low-rigidity filling resin, and therefore has low rigidity and good deformation absorption. The joining structures of the first and second embodiments having nanostructure springs also have good deformation absorption because nanosprings have low rigidity. On the other hand, in a joint structure having a millimeter-order surface fastener, the bending rigidity of the spring is proportional to the cube of the wire diameter. Therefore, the rigidity of the millimeter-order surface fastener having a large wire diameter is very large, and the deformation absorption is low. The stress generated in the spring is proportional to the square of the wire diameter. Therefore, although the stress generated in the spring is small in the joint structure having the nanostructure spring, a very large stress is generated in the milli-order and the spring itself is easily broken. Therefore, the high deformation absorption, which is one of the effects of the first and second embodiments, can be realized by using a nano-order spring layer.

  In contrast to the three types of bonding layer failure modes shown in FIGS. 2A to 2C, the known bonding structure having no spring does not improve the strength due to the spring. In the joint structure having a milli-order spring, the strength of the spring itself is large, but the distance between the joint end and the spring is large, and therefore it is difficult to prevent the mode shown in FIG. Further, since the surface area of the spring is smaller than that of the nano-order spring, the effect of preventing the mode shown in FIG. 2C is small. For these reasons, the improvement in the reliability of the joint, which is one of the effects of the first and second embodiments, can be realized by using a nano-order spring layer.

  By the way, in general, a material such as silicon nitride used for the spring has a higher thermal conductivity than the filling resin. Therefore, the thermal resistance of the joining structure in which the spring is engaged in both the milli-order and the nano-order can be reduced as compared with the joining structure having no spring and the joining structure in which the upper and lower springs are not engaged.

  Insulation properties are ensured by adjusting the resin thickness in any joint structure.

  In terms of manufacturability, the thickness structure is less constrained in joint structures that do not have springs or in which the upper and lower springs are not engaged, whereas thickness restrictions are larger in structures that have milli- or nano-order springs. Become. However, a structure having a milli-order or nano-order spring can be bonded at room temperature, so that the residual stress after bonding can be reduced, and repair can be performed before resin filling.

  For these reasons, the first and second embodiments can be selected and used according to the application in consideration of the above-described properties. Thereby, the reliability requested | required by each use can be improved.

  FIG. 10 is a schematic cross-sectional view of a joint structure according to the third embodiment of the present invention. Unlike the first and second embodiments, this embodiment has a joining structure for joining a resin and a flat plate-like member. In this embodiment, the coil-shaped spring layer 32 is provided only on the surface of the member to be bonded 31 among the surfaces of the resin 33 and the member to be bonded 31 and extends into the resin 33 of the member to be bonded. That is, the sprinkling layer is provided at the interface between the member to be bonded 31 and the resin 33 serving as the other bonding member. Also according to the present embodiment, high reliability can be obtained for the modes of FIGS. 2A and 2C as in the second embodiment.

  A junction structure according to a fourth embodiment of the present invention will be described with reference to FIGS.

  In the spring layer manufacturing method described with reference to FIGS. 3 and 4, when the atoms are deposited by the oblique evaporation method, the spring is controlled in a multi-linear shape or a polygonal shape including a plurality of linear portions by controlling the rotation method of the joining member. Can grow into.

  FIG. 11 shows a cross-sectional photograph of a multi-linear spring layer (hereinafter referred to as “bi-linear shape”) having two linear portions as an example of the nano-structure spring layer having such a multi-linear shape. . If the springs are multi-linear or polygonal, the density of the springs can be increased, which is effective for improving reliability and reducing thermal resistance.

  FIGS. 12A to 12C show a joining structure by a multi-linear (hereinafter, referred to as “three linear shapes”) spring layer having three linear portions.

  As shown in FIG. 12A, the spring 32 (24) includes a straight portion 32a (24a) extending upward (downward) from the surface of the member to be joined 31 (21), and an upper end of the straight portion 32a (24a) ( The linear portion 32b (24b) extends upward (downward) from the lower end and the linear portion 32c (24c) extends upward (downward) from the upper end (lower end) of the linear portion 32b (24b). A spring is formed by forming these three straight portions into a polygonal line connected to each other.

  As shown in FIG. 12A, the surface of the member 21 to be joined provided with the trilinear spring 24 and the surface of the member to be joined 31 provided with the trilinear spring 32 are faced to each other. Then, as shown in FIG. 12B, the member 21 and the member 31 are pressed. A plastic deformation is generated in the spring by the pressing force at this time, and a portion where the bending between the linear portions of the spring becomes large is generated. That is, the springs 24 and 32 are deformed into a hook shape, and a place where they are caught is generated. Thereby, the to-be-joined member 21 and the to-be-joined member 31 are joined by high reliability, and are positioned mutually. Furthermore, as shown in FIG. 12C, filling the resin 33 improves the bonding reliability.

  Also with the bilinear spring shown in FIG. 11, the same joining structure as in the case of using the trilinear spring shown in FIG. 12 is possible. As will be described below, it is preferable to use a spring having three or more straight portions.

  FIGS. 13 and 14 show the results of simulating the plastic deformation behavior when a bilinear spring and a trilinear spring are pressed, respectively, using the finite element method.

  In the case of the bilinear spring shown in FIG. 13, before being pressed, the straight portion b extends upward from the upper end of the straight portion a, but when pressed, it is substantially parallel to the surface of the member to be joined. When the load is subsequently unloaded, the straight portion b slightly approaches the original shape due to the spring back, and thus extends upward from the upper end of the straight portion a as before pressing. On the other hand, in the case of the trilinear spring shown in FIG. 14, before being pressed, the linear portion c extends upward from the upper end of the linear portion b, but when pressed, it extends downward from the end of the linear portion b. . Even if it is unloaded after that, the extending direction of the straight line portion c is maintained. That is, in the case of a multi-linear spring having three or more linear portions, the hook shape has a larger bending degree after plastic deformation than in the case of a bi-linear spring. Therefore, multi-linear springs having three or more straight portions are easier to fit than bi-linear springs. As a result, if a multi-linear spring having three or more straight portions is used, a highly reliable joint structure having greater joint strength can be obtained.

  FIGS. 15A to 15C are schematic cross-sectional views of a joining structure according to a fifth embodiment of the present invention. In this embodiment, as shown in FIG. 15 (a), unlike the other embodiments, the surface of one member 21 to be joined is provided with a multi-line (tri-linear) spring layer 24, and the other A coil-shaped spring layer 32 is provided on the surface of the member to be joined 31. That is, the shape of the spring differs between the upper and lower members to be joined. As shown in FIG. 15 (b), also in this joining structure, by pressing the joining member at the time of joining, as shown in FIG. 14, the multi-linear spring is deformed into a hook shape with a large degree of bending. The deformed multi-linear spring meshes with the coil-shaped spring, whereby the joined members 21 and 31 are joined and positioned relative to each other. Thereby, joint strength improves and high joint reliability is obtained. Moreover, rattling between both members can be prevented. Furthermore, as shown in FIG. 15C, filling the resin 33 improves the bonding reliability.

  FIG. 16 is a schematic cross-sectional view of the joint structure according to the sixth embodiment of the present invention. Unlike the other embodiments, it is provided on the surface of the member to be bonded 31 and the spring layer 24 having four linear portions (hereinafter referred to as “four linear shapes”) provided on the surface of the member to be bonded 21. The four straight spring layers 32 are separated from each surface of the members 21 and 31 in a vertical direction without being mechanically fitted, and the members 21 and 31 are bonded by the resin 33.

  In this embodiment, the spring layer is not fitted, but the interface of the bonded portion shown in FIG. 2A and the interface between the spring and the filling resin shown in FIG. The reliability of the mode to be improved can be improved. In the case of joining with resin, in general, the strength of the mode in which the interface shown in FIGS. 2A and 2C peels is smaller than the mode in which the crack propagates inside the resin shown in FIG. Therefore, since the reliability of the two modes in FIGS. 2A and 2C is improved by this embodiment, the reliability of bonding with resin can be improved.

  In addition, since the density of the springs can be increased by using a multi-line spring, it is effective for improving the reliability of bonding and reducing the thermal resistance. Further, in this embodiment, since the spring is not deformed, an equivalent joint strength can be obtained if it is a multi-linear shape having two or more straight portions.

  As a modification of the present embodiment, one of the spring layer 24 and the spring layer 32 can be changed to a coiled spring layer.

  FIG. 17 is a schematic cross-sectional view of the joint structure according to the seventh embodiment of the present invention. Unlike the other embodiments, a multi-line (four straight line) spring layer is used for the bonding structure for bonding the resin 33 and the flat plate-shaped member 31. In the present embodiment, the spring layer 32 is disposed only on the surface of the member to be bonded among the surfaces of the resin 33 and the member to be bonded 31. Thereby, high reliability is obtained for the modes of FIGS. 2 (a) and 2 (c). Moreover, since the density of a spring can be increased by using a multi-linear spring, it is effective for improving reliability and reducing thermal resistance.

  FIG. 18 is a schematic sectional view of a semiconductor device according to an eighth embodiment of the present invention. The present embodiment is a resin mold type semiconductor device, and each surface of the semiconductor element 1, the lead frame 3 and the heat dissipation base 5 in the embodiment of FIG. 5 Unlike the first embodiment, not only the spring layer is provided on the insulating layer 4, but also the coiled spring layer 4d is provided at the interface between the lead frame 3 and the resin 121 (in the drawing). See enlarged view). By this spring layer 4d, the interface strength between the lead frame 3 and the sealing resin 121 is improved, and the peeling between the lead frame 3 and the sealing resin 121 can be prevented.

  In addition, this invention is not limited to each embodiment mentioned above, Various modifications are included. For example, each of the above-described embodiments has been described in detail for easy understanding of the present invention, and is not necessarily limited to one having all the configurations described. A part of the configuration of an embodiment can be replaced with the configuration of another embodiment, and further, the configuration of another embodiment can be added to the configuration of an embodiment. Furthermore, it is possible to add, delete, or replace other configurations for a part of the configuration of each embodiment.

  For example, the size, shape, and arrangement density of the springs may be different for each member to be joined or for each joint. The material of the spring is not limited to the above-mentioned silicon nitride and nickel, and a ceramic material such as aluminum nitride and a metal material such as copper can be used. That is, the size, shape, arrangement density, and material of the spring can be appropriately selected or changed according to the mechanical strength, electrical characteristics, and thermal characteristics of the joint. Various solid materials such as metals, resins, and ceramics can be applied as the members to be joined.

  Further, in the semiconductor device of FIG. 1, the semiconductor element 1 and the lead frame are provided by providing sprinkled nanostructures made of a metal having good solder wettability such as nickel on the joint surface of the lead frame 3 with the semiconductor element 1. The bonding strength can be improved while ensuring the electrical conductivity with 3. In addition, the thermal resistance between the semiconductor element 1 and the lead frame 3 is reduced, and heat dissipation is improved. In other words, this configuration is obtained by replacing the resin, which is one member to be joined in FIG. 10, with solder.

DESCRIPTION OF SYMBOLS 1 ... Semiconductor element 2 ... Solder 3 ... Lead frame 4 ... Insulating layer 4a, 4b, 4d ... Spring layer 4c ... Resin 5 ... Radiation base 21 ... Joined member 22 ... Surface layer 23 ... Vapor deposition atom 24 ... Spring layer 31 ... Covered Joining member 32 ... spring layer 33 ... resin 121 ... sealing resin

Claims (9)

In a joining structure comprising a first member, a second member, and a joining portion that joins the first member and the second member,
The joint has a plurality of spring-shaped nanostructures;
The plurality of spring-shaped nanostructures are provided on at least one surface of the first member and the second member;
In the joint portion, a spring-shaped nanostructure provided on the surface of the first member and a spring-shaped nanostructure provided on the surface of the second member are mutually connected to the joint surface. Left vertically and filled with resin,
The joining structure, wherein the first member and the second member are joined by the resin.   2. The joining structure according to claim 1, wherein at least one of a spring-shaped nanostructure provided on a surface of the first member and a spring-shaped nanostructure provided on a surface of the second member. Is a coiled structure. The joint structure according to claim 1,
At least one of a spring-shaped nanostructure provided on the surface of the first member and a spring-shaped nanostructure provided on the surface of the second member has a plurality of straight lines. Joining structure characterized by being in a shape. In the junction structure according to claim 3,
The multi-line shape has three or more straight portions. In a joining structure comprising a first member, a second member, and a joining portion that joins the first member and the second member,
The joint has a plurality of spring-shaped nanostructures;
The plurality of spring-shaped nanostructures are provided on at least one surface of the first member and the second member;
In the joint, a spring-shaped nanostructure provided on the surface of the first member and a spring-shaped nanostructure provided on the surface of the second member are fitted together. And
One of a spring-shaped nanostructure provided on the surface of the first member and a spring-shaped nanostructure provided on the surface of the second member has a plurality of linear portions. And the other is coiled,
A joining structure, wherein the multi-linear nanostructure deformed into a hook shape meshes with the coil-shaped nanostructure.   6. The joining structure according to claim 5, wherein the multi-linear shape has three or more straight portions.   2. The bonding structure according to claim 1, wherein, in the bonding portion, the spring-shaped nanostructure is made of an insulating ceramic, the resin is insulating, and the first member and the second member Is joined by the joint having an insulating property.   6. The joining structure according to claim 5, wherein, in the joining portion, the spring-shaped nanostructure is made of an insulating ceramic, further filled with an insulating resin, and the first member and the second member. Are joined by the joint having insulating properties.   9. The joint structure according to claim 7, wherein the insulating ceramic is silicon nitride.

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