Semiconductor device and method for manufacturing same, and resin composition for forming primer layer

Abstract

Provided is a semiconductor device comprising a semiconductor element mounted on a substrate, a sealing layer that seals the semiconductor element, and a primer layer that is formed using a resin composition for forming a primer layer and covers at least a side face of the semiconductor element.

Description

Semiconductor Device, Method of Manufacturing the Same, and Resin Composition for Forming Primer Layer

[0001] The present disclosure relates to a semiconductor device, a method of manufacturing the same, and a resin composition for forming a primer layer.

[0002] In recent years, in the technical field of automobiles, electrification has been progressing, particularly from the perspective of reducing the environmental load on the earth, and in-vehicle devices tend to have higher voltages. Moreover, from the perspective of improving fuel efficiency, weight reduction and space saving of semiconductor devices are required. For these reasons, there are demands for improving characteristics such as withstand voltage and withstand current that can be handled in one semiconductor device and power module.

[0003] On the other hand, from the perspective of reducing the environmental load on the earth as described above, the spread of renewable energy is also progressing. Specifically, there are also demands for improving characteristics such as withstand voltage and withstand current that can be handled in one semiconductor device and power module by utilizing high voltages and high currents from solar cells and wind power generation. Furthermore, from the perspective of reliability, semiconductor devices and power modules are required to suppress heat resistance and leakage current as the characteristics such as withstand voltage and withstand current are improved. Therefore, in recent years, development has also been promoted for members with heat resistance and high insulation properties.

[0004] In response to such demands, in-vehicle device manufacturers and semiconductor manufacturers, etc., are promoting development by changing the circuit boards of conventional devices to high heat dissipation ceramic circuit boards. Also, conventional devices adopt a sealing method using liquid sealing materials such as liquid silicone gel and liquid epoxy, but development is also being promoted to change to sealing methods such as transfer molding and compression molding using solid sealing materials. Thus, a method that enables weight reduction and space saving while achieving desired withstand voltage and withstand current characteristics by applying a solid sealing material to a ceramic circuit board has been studied.

[0005] However, as mentioned above, when switching from conventional sealing methods using soft materials such as liquid silicon gel and liquid epoxy to sealing methods using solid sealing materials such as sealing resins for ceramic circuit boards, delamination of the sealing layer formed using the sealing resin (hereinafter referred to as the sealing resin layer) is likely to occur. As seen during heat cycle tests, which are used to evaluate the reliability of semiconductor devices, delamination mainly occurs between the sealing resin layer and the substrate or semiconductor element. Since delamination creates a space inside the semiconductor device, significantly reducing the reliability of the semiconductor device, delamination is unacceptable and improvement is desired.

[0006] Japanese Patent Publication No. 2020-83930

[0007] The causes of delamination in semiconductor devices include thermal stress within the device. The substrate and the encapsulating resin layer are bonded together as solids, and their coefficients of linear expansion are different. Therefore, stress caused by the expansion and contraction of the components during the thermal cycle of heating and cooling is thought to be a cause of delamination. One method known to improve delamination is to provide a primer layer between the encapsulating resin layer and the substrate or semiconductor element to enhance the adhesion between the components. For example, Patent Document 1 discloses a resin composition for forming a primer layer provided between the encapsulating resin layer and the substrate or semiconductor element.

[0008] However, in recent years, there has been a growing demand for higher levels of voltage and current resistance, and therefore, further research is needed to improve the delamination of the encapsulating layer in order to realize highly reliable semiconductor devices and power modules. Accordingly, embodiments of this disclosure provide a highly reliable semiconductor device with excellent heat resistance and adhesion, and the ability to improve the delamination of the encapsulating layer, as well as a method for manufacturing the same. Furthermore, other embodiments of this disclosure provide a resin composition that can be suitably used to form a primer layer capable of improving the delamination of the encapsulating layer in a semiconductor device.

[0009] In their research, the inventors found that delamination in semiconductor packages after encapsulation often occurs between the side surface of the semiconductor element and the encapsulation layer (encapsulation resin layer). Therefore, the inventors investigated methods to improve the adhesion between the side surface of the semiconductor element and the encapsulation layer, leading to the completion of the present invention. That is, this disclosure includes the following embodiments. However, this disclosure is not limited to the following embodiments and includes various embodiments.

[0010] <1> A semiconductor device comprising a semiconductor element mounted on a substrate, a sealing layer that encapsulates the semiconductor element, and a primer layer formed from a resin composition for forming a primer layer, which covers at least the side surface of the semiconductor element.

[0011] <2> The semiconductor device according to <1>, wherein the primer layer forming resin composition comprises at least one resin selected from the group consisting of polybenzoxazole, polyamide, polyamideimide, and polyimide.

[0012] <3> The semiconductor device according to <1> or <2> above, wherein the glass transition temperature of the resin composition for forming the primer layer is 200°C or higher.

[0013] <4> The semiconductor device according to any one of <1> to <3> above, wherein the coefficient of linear expansion of the primer layer forming resin composition at 70 to 140°C is 25 to 120 ppm / °C.

[0014] <5> The semiconductor device according to any one of <1> to <4> above, wherein the semiconductor element includes at least one selected from the group consisting of a Si semiconductor element, a SiC semiconductor element, and a GaN semiconductor element.

[0015] <6> The semiconductor device according to any one of <1> to <5> above, wherein the semiconductor element has a bare surface exposed by dicing the wafer.

[0016] <7> The semiconductor device according to any one of <1> to <6> above, wherein the sealing layer is a cured product of a sealing resin composition containing an epoxy resin.

[0017] <8> A semiconductor device according to any one of <1> to <7> above, wherein two or more semiconductor elements are mounted perpendicular to the substrate.

[0018] <9> A resin composition for forming a primer layer, used to form a primer layer provided between the side surface of a semiconductor device and the sealing layer.

[0019] <10> The primer layer forming resin composition according to <9> above, wherein a laminate is formed in which a semiconductor element and a sealing layer formed using a sealing resin composition are joined via a primer layer formed using the primer layer forming resin composition, and the shear strength between the semiconductor element and the sealing layer at 200°C is 10 MPa or more.

[0020] <11> The primer layer forming resin composition according to <9> or <10> above, wherein the viscosity at 25°C, as measured using an E-type viscometer, is 13,000 mPa·s or less.

[0021] <12> A method for manufacturing a semiconductor device, comprising the steps of: forming a primer layer on at least the side surface of a semiconductor element mounted on a substrate using a primer layer forming resin composition; and forming a sealing layer that covers the semiconductor element and the primer layer using a sealing resin composition.

[0022] <13> A method for manufacturing a semiconductor device according to <12>, further comprising the step of mounting semiconductor elements on a substrate, wherein in the step, two or more semiconductor elements are mounted in the direction perpendicular to the substrate.

[0023] <14> The method for manufacturing a semiconductor device according to <13>, wherein in the step of forming the primer layer, the sides of each of two or more semiconductor chips mounted on the substrate are collectively coated with the primer layer forming resin composition.

[0024] <15> A method for manufacturing a semiconductor device, comprising the steps of: forming a primer layer on the side surface of a semiconductor element using a primer layer forming resin composition; mounting the semiconductor element having the primer layer formed on its side surface onto a substrate; and forming a sealing layer covering the semiconductor element and the primer layer using a sealing resin composition. The disclosure of this application is related to the subject matter described in Japanese Patent Application No. 2024-225690, filed on December 20, 2024, all of which are incorporated herein by reference.

[0025] According to embodiments of the present disclosure, a highly reliable semiconductor device having a primer layer capable of improving the peeling of the sealing layer, and a method for manufacturing the same can be provided. Furthermore, according to other embodiments of the present disclosure, a resin composition suitably usable for forming the primer layer in the above-mentioned semiconductor device can be provided.

[0026] Figure 1 is a schematic front view showing an example of a semiconductor device according to one embodiment. Figure 2 is a schematic cross-sectional view showing an example of a semiconductor device according to one embodiment, along the line A-A in Figure 1. Figure 3 is a schematic cross-sectional view showing an example of a semiconductor device according to one embodiment. Figure 4 is a schematic cross-sectional view showing another example of a semiconductor device according to one embodiment. Figure 5A is a diagram illustrating an example of a method for manufacturing a semiconductor device according to one embodiment, and is a cross-sectional view illustrating one step. Figure 5B is a diagram illustrating an example of a method for manufacturing a semiconductor device according to one embodiment, and is a cross-sectional view illustrating one step. Figure 5C is a diagram illustrating an example of a method for manufacturing a semiconductor device according to one embodiment, and is a cross-sectional view illustrating one step. Figure 6A is a diagram illustrating another example of a method for manufacturing a semiconductor device according to one embodiment, and is a cross-sectional view showing one step. Figure 6B is a diagram illustrating another example of a method for manufacturing a semiconductor device according to one embodiment, and is a cross-sectional view showing one step. Figure 6C is a diagram illustrating another example of a method for manufacturing a semiconductor device according to one embodiment, and is a cross-sectional view showing one step. Figure 6D is a diagram illustrating another example of a method for manufacturing a semiconductor device according to one embodiment, and is a cross-sectional view showing one step. Figure 7A is a diagram illustrating yet another example of a semiconductor device manufacturing method according to one embodiment, and is a cross-sectional view showing one step. Figure 7B is a diagram illustrating yet another example of a semiconductor device manufacturing method according to one embodiment, and is a cross-sectional view showing one step. Figure 7C is a diagram illustrating yet another example of a semiconductor device manufacturing method according to one embodiment, and is a cross-sectional view showing one step.

[0027] Preferred embodiments of the present disclosure are described in detail below. However, the present disclosure is not limited to the embodiments described below. In the present disclosure, numerical ranges indicated using "~" indicate a range that includes the numbers before and after "~" as the minimum and maximum values, respectively. In numerical ranges described stepwise in the present disclosure, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range. Also, the upper or lower limits of numerical ranges described in the present disclosure may be replaced with values ​​shown in the examples.

[0028] In this disclosure, each component may contain one or more of the applicable substances unless otherwise specified. In this disclosure, the content of each component in the resin composition means the total amount of the multiple substances present in the resin composition, unless otherwise specified, if multiple substances corresponding to each component are present in the resin composition.

[0029] In this disclosure, "top surface of semiconductor device" means the surface opposite to the substrate side on which the semiconductor device is mounted, and refers to the surface (front) on which the circuit is formed. Furthermore, "side surface of semiconductor device" refers to the newly exposed surface (bare surface) of the semiconductor device, which is formed by dicing a wafer on which a circuit has been formed, and refers to the surface that has not undergone any surface treatment such as polishing.

[0030] In this disclosure, the term "process" includes not only processes that are independent of other processes, but also processes that cannot be clearly distinguished from other processes, as long as the intended function of that process is achieved.

[0031] In this disclosure, when embodiments are described with reference to the drawings, the configuration of such embodiments is not limited to the configuration shown in the drawings. Furthermore, the sizes of the members in each figure are conceptual, and the relative relationships between the sizes of the members are not limited to the relationships shown in the drawings.

[0032] <1> Semiconductor Device One Embodiment relates to a semiconductor device. As shown in Figures 1 and 2, the semiconductor device 10 of this embodiment includes a semiconductor element 2 mounted on a substrate 1, a sealing layer 3 that seals the semiconductor element 2, and a primer layer 4 formed from a primer layer forming resin composition that covers at least the side surface 2a of the semiconductor element 2. As shown in the plan view of Figure 1, the primer layer 4 may be formed along the four side surfaces of the semiconductor element 2, and the semiconductor element 2 and the primer layer 4 are covered by the sealing layer 3.

[0033] Figure 3 is a schematic cross-sectional view showing an example of a semiconductor device according to this embodiment. As shown in Figure 3, the semiconductor device 10 includes a die pad 1a, a lead 1b, a semiconductor element 2, a sealing layer 3, a primer layer 4, and a wire 5. In the semiconductor device 10 shown in Figure 3, the primer layer 4 is provided not only on the side surface 2a of the semiconductor element 2, but also on a part of the surface of the die pad 1a and on the surface of the lead 1b. As shown in Figure 3, from the viewpoint of improving the adhesion between the semiconductor element and the sealing layer, the primer layer may be provided not only on the side surface 2a of the semiconductor element, but also on other locations that come into contact with the sealing layer. For example, in addition to the configuration shown in Figure 3, the primer layer may be provided to cover the upper surface 2b of the semiconductor element 2, in addition to the side surface 2a of the semiconductor element.

[0034] Generally, semiconductor devices include semiconductor elements and encapsulating members (encapsulating layers) as constituent components, and it is known that delamination is likely to occur between the semiconductor elements and the encapsulating layer. Furthermore, detailed studies by the present inventors have confirmed that most delamination occurs at the interface between the side surface of the semiconductor element and the encapsulating layer. In contrast, according to this embodiment, by having a primer layer on at least the side surface of the semiconductor element, it is possible to effectively suppress the occurrence of delamination and provide a highly reliable semiconductor device. The configuration of the semiconductor device will be described in more detail below.

[0035] (Semiconductor Element) In the semiconductor device according to this embodiment, the configuration of the semiconductor element is not particularly limited. The semiconductor element typically includes a chip, which is joined to the substrate with solder, sintered silver, or sintered copper, and is further electrically connected to the circuit by Al wire, Au wire, TSV (Through Silicon Via), etc. From the viewpoint of making the effect of the primer layer significant, it is preferable that the semiconductor element has a bare surface exposed by dicing the wafer during chip manufacturing. It is preferable that the semiconductor element includes at least one selected from the group consisting of Si semiconductor elements, SiC semiconductor elements, and GaN semiconductor elements. That is, in the semiconductor element, it is preferable that the main material of the chip is one selected from the group consisting of silicon (Si), silicon carbide (SiC), and gallium nitride (GaN).

[0036] In some embodiments, the semiconductor device may have a structure in which two or more semiconductor elements are mounted perpendicular to the substrate (the semiconductor element mounting surface of the substrate). When two or more semiconductor elements are mounted, the sizes of each semiconductor element may be different or the same. Figure 4 is a schematic cross-sectional view showing an example of a semiconductor device having a structure in which two or more semiconductor elements are mounted. The semiconductor device 10 shown in Figure 4 has a structure in which semiconductor elements 2A and 2B of different sizes are stacked, and primer layers 4 are provided on the sides of semiconductor elements 2A and 2B, respectively. In Figure 4, reference numeral 1 represents the substrate, 3 represents the sealing layer, and 5 represents the wire. The semiconductor device may have a structure in which two or more semiconductor elements are mounted on a substrate by alternately repeating the stacking of semiconductor elements 2A and semiconductor elements 2B.

[0037] (Substrate) The substrate has an upper surface (front) on which a circuit is formed and a lower surface (back) on which no circuit is formed, and the semiconductor element is mounted on the upper surface of the substrate. The substrate is not particularly limited and may have a configuration typical of the art, but a substrate made of inorganic material is preferred, and among these, a ceramic substrate is preferred. Examples include ceramic substrates containing alumina, alumina zirconia, aluminum nitride, silicon nitride, etc. In some embodiments, the ceramic substrate may be plated. The plating treatment may be, for example, Cu plating, Ni plating, Ag plating, Au plating, or Au / Pd / Ni plating. In some embodiments, the substrate may have a substantially plate shape. In other embodiments, it may have a lead frame shape. In some embodiments, as an example of the configuration of a semiconductor element mounted on the substrate, a configuration in which a semiconductor element is mounted on the upper surface of a plated ceramic substrate, and the semiconductor element and the circuit of the substrate are electrically connected by wires. The substrate may also be a semiconductor element (chip), a semiconductor wafer, or an interposer.

[0038] (Sealing Layer) The sealing layer can typically be composed of an organic material such as a resin. Hereinafter, a sealing layer composed of a resin will be referred to as a sealing resin layer. In some embodiments, the sealing layer is preferably a sealing resin layer formed from a cured product of a sealing resin composition containing an epoxy resin. The above sealing resin composition is not particularly limited and may be constructed by applying techniques well known in the art. In some embodiments, the sealing resin composition includes an epoxy resin and a curing agent, and may further include additives such as a colorant, mold release agent, coupling agent, and low-stress additive as needed. Sealing resin compositions are also available as commercially available products. For example, as an epoxy sealing resin, CEL-420HFC, CEL-400 series, etc. manufactured by Resonac Co., Ltd. can be suitably used.

[0039] (Primer layer) The semiconductor device according to this embodiment may have a primer layer between each component, and is characterized by having a primer layer that covers at least the side surface of the semiconductor element. By providing a primer layer, the adhesion between each component can be easily improved. In particular, since the primer layer is provided at least on the side surface of the semiconductor element, the adhesion between the side surface of the semiconductor chip, whose bare surface is exposed by dicing, and the sealing resin layer can be ensured, and peeling during cycle testing can be effectively prevented.

[0040] The primer layer is preferably formed from a dried or cured film using a resin composition known as a primer layer forming material in the semiconductor technology field. In some embodiments, when constructing a power semiconductor device using a semiconductor element having the silicon carbide (SiC) chip or gallium nitride (GaN) chip, better heat resistance and insulation are required than in conventional semiconductor devices. Therefore, the resin composition used to form the primer layer (hereinafter referred to as the primer layer forming resin composition, or simply the resin composition) preferably contains a resin having excellent heat resistance and insulation.

[0041] In some embodiments, from the viewpoint of heat resistance, the glass transition temperature (Tg) of the resin may be preferably 200°C or higher, more preferably 250°C or higher, and even more preferably 300°C or higher. Also, in some embodiments, from the viewpoint of making it easier to suppress peeling of the sealing layer, the coefficient of linear expansion of the resin at 70 to 140°C may be preferably 25 to 120 ppm / °C. Similarly, from the viewpoint of heat resistance and suppression of peeling of the sealing layer, it is preferable that the Tg and coefficient of linear expansion of the resin composition constructed using the resin be within the above ranges. The glass transition temperature and the coefficient of linear expansion are values ​​obtained by measuring the dried film or cured film of the resin or resin composition constituting the primer layer. The specific measurement method is as described in the examples below, but the glass transition temperature is obtained from the peak position of tanδ using a dynamic viscoelasticity measuring device under conditions of a chuck distance of 20 mm and a heating rate of 3°C / min. Furthermore, the coefficient of linear expansion was calculated using a thermomechanical analyzer under the conditions of a chuck distance of 10 mm, a load of 10 g, and a heating rate of 10 °C / min. The displacements at 70 °C and 140 °C were connected by a straight line, and the value was calculated from the slope of that line.

[0042] For example, heat cycle tests simulating high operating temperatures (high Tj) for power semiconductors are conducted at temperatures of 175°C or higher. Therefore, having a Tg of 200°C or higher in the resin composition makes it easy to maintain excellent adhesion even at high temperatures. Furthermore, if the coefficient of linear expansion of the resin composition is within the above range, the generation of stress due to thermal expansion and contraction of the substrate can be suppressed, and the adhesion with the sealing layer can be easily improved. In some embodiments, the coefficient of linear expansion (CTE) of the resin composition at 70 to 140°C is preferably in the range of 40 to 90 ppm / °C, more preferably in the range of 50 to 70 ppm / °C, and even more preferably in the range of 55 to 65 ppm / °C.

[0043] When a primer layer is formed using a resin or resin composition having the above-mentioned Tg and / or linear expansion coefficient within the above range, even in the form of a power semiconductor device, it is possible to easily suppress a decrease in adhesion between members during a heat cycle test. As the above resin, at least one resin selected from the group consisting of polybenzoxazole, polyamide, polyamideimide, and polyimide can be preferably used. The resin composition preferably used for forming the primer layer will be described more specifically in the section of "<3> Resin composition for forming primer layer" described later.

[0044] <2> Method for manufacturing semiconductor deviceOne embodiment of the present invention relates to a method for manufacturing the semiconductor device of the above embodiment. The method for manufacturing the semiconductor device of the present embodiment includes at least a step of forming a primer layer on at least a side surface of a semiconductor element mounted on a substrate using a resin composition for forming a primer layer, and a step of forming a sealing layer covering the semiconductor element and the primer layer using a resin composition for sealing.

[0045] The method for manufacturing the semiconductor device of the present embodiment may further include a step of mounting a semiconductor element on a substrate in order to prepare a semiconductor element mounted on the substrate. In the above step, two or more semiconductor elements may be mounted in a direction perpendicular to the substrate, and a primer layer may be provided on each side surface of the two or more semiconductor elements. As an alternative method, two or more semiconductor elements having a primer layer formed on the side surface in advance may be mounted on the substrate.

[0046] In the method for manufacturing the semiconductor device of the present embodiment, the material for forming the primer layer is not limited, but the resin composition for forming the primer layer described later can be preferably used. In some embodiments, from the viewpoint of workability, a resin composition (varnish) containing polyamideimide can be preferably used as the resin component.

[0047] Hereinafter, a representative example of the manufacturing method of the present embodiment will be specifically described with reference to the drawings. FIGS. 5A to 5C are diagrams for explaining an example of the manufacturing method of a semiconductor device according to an embodiment of the present invention, and FIGS. 5A, 5B, and 5C correspond to each step. As shown in FIGS. 5A to 5C, in some embodiments, the manufacturing method of a semiconductor device includes preparing a semiconductor element 2 mounted on a substrate 1, and forming a primer layer 4 on a side surface 2a of the semiconductor element 2 using a resin composition for forming a primer layer (step Ia), and forming a sealing layer 3 covering the semiconductor element 2 and the primer layer 4 using a resin composition for sealing (step Ib). In the step Ib, the sealing layer 3 is preferably formed so as to cover the upper surface (surface) 2b of the semiconductor element and the entire surface (side surface and upper surface) of the primer layer 4. By sequentially performing the above (step Ia) and (step Ib), a semiconductor device 10 is obtained.

[0048] FIGS. 6A to 6D are diagrams for explaining another example of the manufacturing method of a semiconductor device according to an embodiment of the present invention, and FIGS. 6A, 6B, 6C, and 6D correspond to each step. As shown in FIGS. 6A to 6D, in some embodiments, the manufacturing method of a semiconductor device includes preparing a semiconductor element 2 mounted on a substrate 1, forming a primer layer 4 on the upper surface 2b and the side surface 2a of the semiconductor element 2 using a resin composition for forming a primer layer (step IIa), removing a portion 4b located on the upper surface 2b of the semiconductor element in the primer layer 4, and forming a primer 4a located on the side surface of the semiconductor element (step IIb), and forming a sealing layer 3 covering the entire surface (upper surface and side surface) of the upper surface 2b of the semiconductor element 2 and the primer layer 4a formed on the side surface 2b of the semiconductor element using a resin composition for sealing (step IIc). By sequentially performing the above (step IIa) to (step IIc), a semiconductor device 10 is obtained.

[0049] In step IIb described above, as a method for removing the portion 4b located on the surface 2b of the semiconductor element in the primer layer, for example, polishing with a grinder or removal using deflashing can be applied. The surface of the primer layer 4a formed by step IIb described above and the surface 2b of the semiconductor element 2 constitute a continuous plane. Therefore, according to step IIb described above, a primer layer having a thickness uniform to the thickness of the semiconductor element can be easily formed.

[0050] The semiconductor device manufacturing method described with reference to Figures 5A to 5C and Figures 6A to 6D may further include a step (Step Ia-1) or (Step IIa-1) of mounting semiconductor elements onto a substrate in order to prepare semiconductor elements mounted on the substrate, prior to the step of forming the primer layer described in (Step Ia) or (Step IIa). The number of semiconductor elements mounted on the substrate may be one or two or more. In some embodiments, it is preferable to mount two or more semiconductor elements perpendicular to the substrate in (Step Ia-1) or (Step IIa-1). When two or more semiconductor elements are mounted on the substrate, it is preferable to collectively coat each side surface of the two or more semiconductor elements with the primer layer forming resin composition in the step of forming the primer layer. According to such embodiments, highly reliable and high-performance semiconductor devices can be easily provided.

[0051] Figures 7A to 7C illustrate yet another example of a semiconductor device manufacturing method according to an embodiment of the present invention, with Figures 7A, 7B, and 7C corresponding to each step. As shown in Figures 7A to 7C, in some embodiments, the semiconductor device manufacturing method may include: forming a primer layer 4 on the side surface 2a of a semiconductor element 2 using a primer layer forming resin composition (Step IIIa); mounting the semiconductor element 2 with the primer layer 4 formed on its side surface onto a substrate 1 (Step IIIb); and forming a sealing layer 3 that covers the semiconductor element 2 and the primer layer 4 using a sealing resin composition (Step IIIc). In Step IIIc, it is preferable that the sealing layer is formed to cover the upper surface 2b of the semiconductor element 2 and the entire surface (upper surface and side surface) of the primer layer 4. A semiconductor device 10 is obtained by sequentially carrying out Steps IIIa to IIIc.

[0052] In the semiconductor device manufacturing method of this embodiment, the method for forming the primer layer is not particularly limited, and well-known methods for forming coating films can be applied. For example, a coating film may be formed using spraying, dispensing, or spin coating. Alternatively, a method can be applied in which a resin composition for forming the primer layer is filled into a container, and the side surface of the semiconductor element is immersed in the resin composition for dipping. This method can be suitably applied in the method described with reference to Figures 7A to 7C.

[0053] In some embodiments, the viscosity of the primer layer-forming resin composition used to form the primer layer may be 13,000 mPa·s or less. In some embodiments, the viscosity may be 10,000 mPa·s or less, 8,000 mPa·s or less, 5,000 mPa·s or less, 1,000 mPa·s or less, or 500 mPa·s or less. The viscosity of the primer layer-forming resin composition is preferably adjusted within the range of 2 mPa·s or more and 13,000 mPa·s or less, depending on the application method during film formation.

[0054] For example, when applying the dipping method, the viscosity of the primer layer-forming resin composition is preferably 2 to 400 mPa·s, more preferably 2 to 150 mPa·s. When applying the spraying and dispensing methods, the viscosity of the primer layer-forming resin composition is preferably about 3000 to 13000 mPa·s from the viewpoint of facilitating thick film formation. Furthermore, from the viewpoint of suppressing entrapment voids, the viscosity is preferably 1000 mPa·s or less. Moreover, from the viewpoint of suppressing variations in film thickness, the viscosity is preferably about 5 to 400 mPa·s. The above viscosity values ​​were measured at 25°C using an E-type viscometer. The rotation speed during viscosity measurement is adjusted according to the viscosity category.

[0055] The thickness of the primer layer formed on the side surface of the semiconductor element is preferably uniform to the thickness of the semiconductor element. The primer layer can be obtained by applying a primer layer-forming resin composition to a predetermined location and drying the coating. By adjusting the amount of primer layer-forming resin composition applied, the desired primer layer thickness can be obtained.

[0056] In this embodiment, the primer layer is provided at least on the side surface of the semiconductor element, but additional primer layers may be provided on the surface of other components that form an interface with the sealing layer, if necessary. In some embodiments, the thickness of the additional primer layer is preferably 1 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more, from the viewpoint of ensuring insulation. On the other hand, from the viewpoint of solvent drying, the thickness is preferably 50 μm or less, and more preferably 20 μm or less. In one embodiment, the thickness is preferably in the range of 5 to 10 μm. Therefore, it is preferable to adjust the supply amount of the primer layer forming resin composition so that the thickness after drying falls within the above range.

[0057] The configuration of the substrate on which the semiconductor element is mounted is not particularly limited. In some embodiments, the substrate may be in the form of a lead frame 1A, which consists of a die pad 1a and leads 1b, as shown earlier in Figure 2. The material constituting the substrate is not particularly limited and can be selected from materials well known in the art. For example, from the viewpoint of configuring a power semiconductor device, the die pad material is preferably at least one selected from the group consisting of Ni and Cu. Also, Ag plating may be formed on the surface of one of the materials selected from the group consisting of Ni and Cu. The lead material of the lead frame is preferably selected from the group consisting of Ni and Cu. The chip material of the semiconductor element is also not particularly limited and may be, for example, a silicon wafer (Si), a silicon carbide wafer (SiC), etc.

[0058] The sealing layer (sealing resin layer) can be formed using sealing resin compositions well known in the art. For example, the sealing resin composition may be a liquid or solid epoxy resin composition. The sealing resin layer can be formed, for example, by transfer molding using the sealing resin composition.

[0059] In some embodiments, a method for manufacturing a semiconductor device may further include, for example, the steps of applying and drying a resin composition to a semiconductor element mounting substrate on which a plurality of wirings of the same structure are formed to form a first resin layer (additional primer layer), and optionally forming rewiring on the first resin layer that is electrically conductive to electrodes on the semiconductor element mounting substrate. In addition to the above steps, the method may optionally include the step of forming a second resin layer (protective layer) on the rewiring or on the first resin layer using the resin composition. Furthermore, in addition to the above steps, the method may optionally include the steps of forming external electrode terminals on the first resin layer, and then optionally dicing.

[0060] The method for applying each of the above resin layers is not particularly limited, but spin coating, spray coating, or dispense coating is preferred. The drying method for each of the above resin layers can be carried out by methods known in the art. The primer layer forming resin composition described later also has excellent properties such as sputter resistance, plating resistance, and alkali resistance required in the process of forming rewiring. Therefore, the primer layer forming resin composition described later can also be used as the material for forming the above protective layer. Furthermore, various configurations known in the art can be applied, without being limited to the semiconductor device configuration described above.

[0061] <3> Resin composition for primer layer formation One embodiment of the present invention relates to a resin composition for primer layer formation. The resin composition for primer layer formation comprises an organic solvent and a thermoplastic resin, and preferably further comprises a coupling agent as needed. The composition of the resin composition for primer layer formation will be described below. However, the use of the resin composition is not limited to a primer layer, and it can also be suitably used as a resin material constituting semiconductor devices such as an insulating layer and a protective layer.

[0062] <Thermoplastic Resin> The thermoplastic resin is preferably a resin with excellent heat resistance and insulating properties. In some embodiments, at least one selected from polybenzoxazole, polyamide, polyamideimide, and polyimide can be suitably used. Among these, polyamide and polyamideimide are preferred in that high-temperature treatment for imidization is not required during the manufacture of semiconductor devices, and polyamideimide is even more preferred in terms of heat resistance. However, the resin is not particularly limited, and any resin with excellent heat resistance and excellent adhesion to the sealing member (sealing resin layer) is acceptable. Therefore, with respect to polyimide, if it has a resin structure that is soluble in solvent after imide group formation, polyimide may be the most preferred form in terms of heat resistance.

[0063] In the above-mentioned resin, the polybenzoxazole is not particularly limited and may be a resin obtained by dehydrating and cyclizing a polybenzoxazole precursor such as polyhydroxyamide by heat treatment or chemical treatment using anhydrous phosphoric acid, a base, a carbodiimide compound, etc.

[0064] In the above resin, the polyamide is not particularly limited and may be a resin having an amide bond formed by the reaction of an acid component and an amine component. From the viewpoint of heat resistance, polyamides having an aromatic ring in the molecule (hereinafter referred to as aromatic polyamides) are preferred. From this viewpoint, in aromatic polyamides, it is preferable that at least one of the acid component and amine component used as raw materials is a compound having an aromatic ring. For example, aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid can be suitably used as the acid component. Also, aromatic diamines can be suitably used as the amine component.

[0065] In the above resin, the polyimide is not particularly limited and may be a resin having imide bonds formed by polycondensation of an acid anhydride and a diamine or diisocyanate. From the viewpoint of heat resistance, polyimides having aromatic rings (hereinafter referred to as aromatic polyimides) are preferred. From this viewpoint, in the above aromatic polyimides, it is preferable that at least one of the acid anhydride and the diamine component or diisocyanate component used as raw materials is a compound having an aromatic ring. For example, aromatic tetracarboxylic dianhydrides such as 3,3',4,4'-biphenyltetracarboxylic dianhydride can be suitably used as the acid anhydride. Also, aromatic diamines or aromatic diisocyanates can be suitably used as the diamine component or diisocyanate component.

[0066] In the above-mentioned resin, the polyamide-imide may be any polymer having an amide bond and an imide bond in its molecule, and is not particularly limited. For example, it may be a resin obtained by the reaction of an acid component containing an anhydride (tricarboxylic acid anhydride) or an acid halide thereof of a compound having three carboxyl groups in its molecule with a diamine component or a diisocyanate component. From the viewpoint of heat resistance, a polyamide-imide resin having an aromatic ring (hereinafter referred to as an aromatic polyamide-imide resin) is preferred. From this viewpoint, in an aromatic polyamide-imide resin, it is preferable that at least one of the acid component used as a raw material and the diamine component or diisocyanate component is a compound having an aromatic ring. For example, an aromatic tricarboxylic acid anhydride such as trimellitic anhydride can be suitably used as the acid component. Also, an aromatic diamine or an aromatic diisocyanate can be suitably used as the diamine component or diisocyanate component.

[0067] From the viewpoint of obtaining excellent heat resistance, it is preferable that the polyamide-imide has a glass transition temperature higher than, for example, the upper limit of the operating temperature (Tj) of the power semiconductor. In this specification, "glass transition temperature (Tg)" is a value obtained by performing a dynamic viscoelasticity test using a film obtained by coating and heat-drying a resin dissolved in a solvent.

[0068] In some embodiments, the Tg of the polyamide-imide is preferably 250°C or higher, more preferably 270°C or higher, and even more preferably 300°C or higher.

[0069] When a primer layer is constructed, for example, between components of a semiconductor device using the above-mentioned polyamide-imide having a Tg of 250°C or higher, excellent adhesion can be obtained even in heat cycle tests conducted in high-temperature regions of 250°C or higher. Furthermore, when a power semiconductor device is constructed using the above-mentioned resin, it is possible to suppress the softening of the resin due to heat generated during operation, which can lead to a decrease in adhesion. Therefore, when the polyamide-imide resin of the above embodiment is used, high reliability can be obtained in power semiconductor devices. From this viewpoint, the polyamide-imide resin composition can be suitably used as a resin composition for forming a primer layer.

[0070] In some embodiments, when a diamine is used in the production of polyamide-imide, it is preferable to use an acid halide of trimellitic anhydride as the acid component, and among these, it is particularly preferable to use trimellitic anhydride chloride represented by the following formula (I).

[0071]

[0072] From the above viewpoint, in one embodiment, the polyamideimide preferably contains a structural unit represented by the following formula (Ia).

[0073] In some embodiments, the polyamide-imide preferably contains, as a diamine component or diisocyanate component, at least one compound selected from the group consisting of 9,9-bis(4-aminophenyl)fluorene, 9,9-bis(4-amino-3-methylphenyl)fluorene, 9,9-bis(4-amino-3-chlorophenyl)fluorene, and 9,9-bis(4-amino-3-fluorophenyl)fluorene, 4,4'-methylenebis[2,6-bis(1-methylethyl)benzeneamine], and 2,2-bis[4-(4-aminophenoxy)phenyl]propane. In particular, when compounds having a cardo structure such as 9,9-bis(4-aminophenyl)fluorene, 9,9-bis(4-amino-3-methylphenyl)fluorene, 9,9-bis(4-amino-3-chlorophenyl)fluorene, and 9,9-bis(4-amino-3-fluorophenyl)fluorene are used, it is easy to obtain excellent heat resistance. Furthermore, resins having a glass transition temperature exceeding 200°C tend to be easily obtained.

[0074] In some embodiments, the polyamide-imide may be a resin obtained using a diamine component or diisocyanate component containing at least one of the above compounds, and using the compound represented by (I) above as the acid component. In other embodiments, the resin may be obtained by further adding 1,3-bis(3-aminopropyl)1,1,3,3-tetramethyldisiloxane as the diamine component or diisocyanate component. In yet another embodiment, the polyamide-imide may be a resin obtained by further using other acid components in addition to the compound represented by formula (I) above as the acid component.

[0075] The acid components that can be used may include, for example, the above tricarboxylic acid anhydrides or their acid halides other than the compound represented by formula (I) above, and tricarboxylic acids such as trimellitic acid. In addition, tetracarboxylic acid dianhydrides such as pyromellitic acid anhydride and biphenyltetracarboxylic acid dianhydride, aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, and aliphatic dicarboxylic acids such as adipic acid and sebacic acid may be used as acid components.

[0076] The weight-average molecular weight (Mw) of the polyamide-imide is preferably in the range of 30,000 to 120,000. Polyamide-imides having an Mw within the above range are more likely to form a coating film of a preferred thickness, as described later, during the coating process. The Mw of the polyamide-imide is more preferably in the range of 35,000 to 110,000, and even more preferably in the range of 38,000 to 100,000. The "Mw" described herein is a value measured using gel permeation chromatography on a standard polystyrene basis.

[0077] The above polyamide-imide is preferably soluble in an organic solvent at room temperature, from the viewpoint of workability during film formation. In this specification, "soluble in an organic solvent at room temperature" means that when the solution obtained by adding an organic solvent to the resin and stirring is observed visually at room temperature, there is no precipitate, no turbidity, and the entire solution is transparent. Here, "room temperature" may be in the range of approximately 10°C to 40°C, and is preferably in the range of 20°C to 30°C. In one embodiment, the "solution" means, for example, a solution obtained by adding 1 to 30 g of the resin powder to 100 mL of organic solvent. The above organic solvent will be described later.

[0078] (Method for producing polyamide-imide) Polyamide-imide resins can be produced according to known methods and are not particularly limited. For example, polyamide-imide resins can be produced by the reaction of a diamine component and / or a diisocyanate component with an acid component. The diamine component, diisocyanate component, and acid component are as previously described. The above reaction can be carried out without a solvent or in the presence of an organic solvent. The reaction temperature is preferably in the range of 25°C to 250°C. The reaction time can be appropriately adjusted depending on the batch size, the reaction conditions adopted, etc.

[0079] The organic solvent (reaction solvent) used in the production of polyamide-imide is not particularly limited. Examples of usable organic solvents include ether-based solvents such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, and triethylene glycol diethyl ether; sulfur-containing solvents such as dimethyl sulfoxide, diethyl sulfoxide, dimethyl sulfone, and sulfolane; cyclic ester (lactone) solvents such as γ-butyrolactone; acyclic ester solvents such as cellosolve acetate; ketone solvents such as cyclohexanone and methyl ethyl ketone; nitrogen-containing solvents such as N-methyl-2-pyrrolidone, dimethylacetamide, and 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone; and aromatic hydrocarbon solvents such as toluene and xylene. One of these organic solvents may be used alone, or two or more may be used in combination. In one embodiment, it is preferable to select and use an organic solvent capable of dissolving the resin to be produced, and it is preferable to use a polar solvent. Polar solvents will be discussed later, but for example, nitrogen-containing solvents are preferred.

[0080] In one embodiment, polyamide-imide can be produced by first producing a precursor of polyamide-imide by reacting an acid component with a diamine component, and then obtaining polyamide-imide by dehydrating and cyclizing this precursor. However, the method of cyclizing the precursor is not particularly limited, and methods well known in the art can be used. For example, a thermal cyclization method in which dehydration and cyclization are performed by heating under normal or reduced pressure, or a chemical cyclization method using a dehydrating agent such as acetic anhydride in the presence or absence of a catalyst can be used.

[0081] In the case of the thermal ring-closing method, it is preferable to remove the water produced in the dehydration reaction from the system. During the dehydration reaction, the reaction solution may be heated to 80°C to 400°C, preferably 100°C to 250°C. Alternatively, an organic solvent that can azeotrope with water, such as benzene, toluene, or xylene, may be used in combination to remove the water azeotropically.

[0082] In the case of the chemical cyclization method, the reaction may be carried out at 0°C to 120°C, preferably 10°C to 80°C, in the presence of a chemical dehydrating agent. As the chemical dehydrating agent, it is preferable to use acid anhydrides such as acetic anhydride, propionic anhydride, butyric anhydride, and benzoic anhydride, or carbodiimide compounds such as dicyclohexylcarbodiimide. During the reaction, it is preferable to use in combination substances that promote cyclization reactions, such as pyridine, isoquinoline, trimethylamine, triethylamine, aminopyridine, and imidazole.

[0083] Chemical dehydrating agents may be used in a ratio of 90 to 600 mol% relative to the total amount of diamine components, and substances that promote the cyclization reaction may be used in a ratio of 40 to 300 mol% relative to the total amount of diamine components. Dehydrating catalysts such as triphenyl phosphite, tricyclohexyl phosphite, triphenyl phosphate, phosphoric acid, phosphorus compounds such as phosphorus pentoxide, and boron compounds such as boric acid and boric anhydride may also be used.

[0084] In the production of polyamide-imide, the ratio (molar ratio) of the acid component to the diamine component (diisocyanate component) is not particularly limited and can be adjusted so that the reaction proceeds without excess or deficiency. In one embodiment, from the viewpoint of the molecular weight and degree of crosslinking of the resulting polyamide-imide resin, it is preferable that the total amount of diamine components be 0.90 to 1.10 moles per 1.00 mole of total acid components, more preferably 0.95 to 1.05 moles, and even more preferably 0.97 to 1.03 moles.

[0085] (Solvent) The solvent can be any solvent capable of dissolving polyamide-imide, and is not particularly limited. A "solvent capable of dissolving polyamide-imide" means a solvent in which, when the solution obtained by adding polyamide-imide powder to the solvent and stirring is observed visually without any particular restrictions on the temperature of the solvent, no precipitate or turbidity is observed, and the entire solution is transparent. In one embodiment, the solvent constituting the resin composition may be the same as the reaction solvent used in the production of the resin. In particular, it is preferable to use a polar solvent.

[0086] Examples of polar solvents include nitrogen-containing compounds such as N-methylpyrrolidone, dimethylacetamide, dimethylformamide, and 1,3-dimethyltetrahydro-2(1H)-pyrimidinone; sulfur-containing compounds such as sulfolane and dimethyl sulfoxide; lactones such as γ-butyrolactone, γ-valerolactone, γ-caprolactone, γ-heptalactone, α-acetyl-γ-butyrolactone, and ε-caprolactone; ketones such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and acetophenone; acyclic esters such as cellosolve acetate; diethylene glycol dialkyl ethers such as ethylene glycol, glycerin, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, and diethylene glycol dibutyl ether; triethylene glycol dimethyl ether and triethylene glycol diethyl ether. Examples include triethylene glycol dialkyl ethers such as triethylene glycol dipropyl ether and triethylene glycol dibutyl ether, tetraethylene glycol dialkyl ethers such as tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetraethylene glycol dipropyl ether and tetraethylene glycol dibutyl ether, diethylene glycol monoalkyl ethers such as diethylene glycol monomethyl ether and diethylene glycol monoethyl ether, triethylene glycol monoalkyl ethers such as triethylene glycol monomethyl ether and triethylene glycol monoethyl ether, and ethers containing tetraethylene glycol monoalkyl ethers such as tetraethylene glycol monomethyl ether and tetraethylene glycol monoethyl ether.

[0087] In some embodiments, the solvent is preferably at least one selected from the group consisting of diethylene glycol dimethyl ether, triethylene glycol, triethylene glycol dimethyl ether, N-methyl-2-pyrrolidone, γ-butyrolactone, γ-valerolactone, δ-valerolactone, γ-caprolactone, ε-caprolactone, α-methyl-γ-butyrolactone, ethyl cellosolve, ethyl cellosolve acetate, butyl cellosolve, butyl cellosolve acetate, cyclopentanone, cyclohexanone, tetrahydrofuran, 1,4-dioxane, dibutyl ether, dimethyl sulfoxide, 1,3-dimethyl-2-imidazolidinone, dimethylacetamide, N,N-dimethylformamide, ethylene carbonate, propylene carbonate, and propylene glycol methyl acetate. When using two or more in combination, they can be mixed in any proportion.

[0088] Among the solvents mentioned above, solvents with relatively low boiling points are preferred from the viewpoint of film-forming properties. For example, diethylene glycol dimethyl ether, triethylene glycol, and triethylene glycol dimethyl ether can be preferably used.

[0089] The amount of solvent in the above-mentioned primer layer-forming resin composition, preferably a polyamide-imide resin composition, can be appropriately adjusted considering viscosity. Although not particularly limited, in one embodiment, the amount of solvent is preferably 500 to 3500 parts by weight per 100 parts by weight of the total amount of resin in the resin composition. More preferably, the solvent is added in a ratio of 5000 to 2000 parts by weight per 100 parts by weight of the total amount of resin.

[0090] (Additives) Additives such as colorants and coupling agents, and additional components such as resin modifiers may be added to the above polyamide-imide resin composition (varnish) as needed. When the polyamide-imide resin composition contains additional components, it is preferable that the amount of additional components is 50 parts by weight or less per 100 parts by weight of the total amount of polyamide-imide resin (solid component) in the polyamide-imide resin composition. By limiting the amount of additional components to 50 parts by weight or less, it becomes easier to suppress a decrease in the physical properties of the resulting coating film. In some embodiments, the above polyamide-imide resin composition may be a varnish containing a polyamide-imide resin and a solvent, and further containing additives as needed. The glass transition temperature and coefficient of linear expansion measured using the dried or cured film of the above varnish are preferably in the same range as in the case of the primer layer forming resin composition described earlier. That is, it is preferable that the dried or cured film of the above varnish has a glass transition temperature of 200°C or higher. Also, the coefficient of linear expansion of the dried or cured film of the above varnish at 70°C to 140°C is preferably 25 to 120 ppm / °C.

[0091] In some embodiments, the polyamide-imide resin composition may contain a coupling agent. Examples of additional components that can be used are given below. (Coupling agent) The coupling agent that can be used is not particularly limited and may be silane-based, titanium-based, or aluminum-based, but silane-based coupling agents are most preferred. While there are no particular restrictions on the silane coupling agent, examples include vinyltrichlorosilane, vinyltris(β-methoxyethoxy)silane, vinyltriethoxysilane, vinyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercap Topropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-ureidopropyltriethoxysilane, 3-ureidopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltris[2-(2-methoxyethoxy)ethoxy]silane, N-methyl-3-aminopropyltrimethoxysilane, triaminopropyltrimethoxysilane, 3-4,5-dihydroimidazole-1-yl-propyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyldimethoxysilane, 3-cyanopropyltriethoxysilane, hexamethyldisilazane, N,Examples include O-bis(trimethylsilyl)acetamide, methyltrimethoxysilane, methyltriethoxysilane, ethyltrichlorosilane, n-propyltrimethoxysilane, isobutyltrimethoxysilane, amyltrichlorosilane, octyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, methyltri(methacryloyloxy)silane, methyltri(glycidyloxy)silane, N-β(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane, octadecyldimethyl[3-(trimethoxysilyl)propyl]ammonium chloride, γ-chloropropylmethyldichlorosilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropylmethyldiethoxysilane, trimethylsilyl isocyanate, dimethylsilyl isocyanate, methylsilyltriisocyanate, vinylsilyltriisocyanate, phenylsilyltriisocyanate, tetraisocyanate silane, and ethoxysilane isocyanate. These may be used individually or in combination of two or more types.

[0092] While there are no particular restrictions on the titanium-based coupling agent, examples include isopropyltrioctanoyl titanate, isopropyl dimethacrylate isostearoyl titanate, isopropyl toridodecylbenzenesulfonyl titanate, isopropyl isostearoyl diacrylic titanate, isopropyl tri(dioctyl phosphate) titanate, isopropyl tricumylphenyl titanate, isopropyl tris(dioctyl pyrophosphate) titanate, isopropyl tris(n-aminoethyl) titanate, tetraisopropyl bis(dioctyl phosphite) titanate, tetraoctyl bis(ditridecyl phosphite) titanate, tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl) phosphite titanate, dicumylphenyl oxyacetate titanate, bis(dioctyl pyrophosphate) oxyacetate titanate, tetraisopropyl titanate, tetrano Examples include malbutylate titanate, butyl titanate dimer, tetra(2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium ethylacetonate, titanium octylene glycolate, titanium lactate ammonium salt, titanium lactate, titanium lactate ethyl ester, titanium triethanolamine, polyhydroxytitanium stearate, tetramethyl orthotitanate, tetraethyl orthotitanate, tetraapropyl orthotitanate, tetraisobutyl orthotitanate, stearyl titanate, cresyl titanate monomer, cresyl titanate polymer, diisopropoxy-bis(2,4-pentadionate)titanium(IV), diisopropyl-bis-triethanolaminotitanate, octylene glycol titanate, tetra-n-butoxytitanium polymer, tri-n-butoxytitanium monostearate polymer, and tri-n-butoxytitanium monostearate. These can be used individually or in combination of two or more types.

[0093] While there are no particular limitations on the aluminum-based coupling agents, examples include aluminum chelates such as ethyl acetate aluminum diisopropylate, aluminum tris(ethyl acetate), alkyl acetate aluminum diisopropylate, aluminum monoacetylacetate bis(ethyl acetate), aluminum tris(acetylacetonate), aluminum monoisopropoxymonoleoxyethyl acetate, aluminum di-n-butoxide-monoethyl acetate, aluminum di-isopropoxide-monoethyl acetate, aluminum isopropylate, mono-sec-butoxyaluminum diisopropylate, aluminum sec-butyrate, and aluminum alcoholates such as aluminum ethylate. These may be used individually or in combination of two or more.

[0094] In some embodiments, from the viewpoint of forming a thick film, the viscosity of the polyamide-imide resin composition is preferably about 3,000 to 13,000 mPa·s. From the viewpoint of suppressing inclusion voids, the viscosity is preferably 1,000 mPa·s or less. Also, from the viewpoint of suppressing variations in film thickness, the viscosity is preferably about 5 to 400 mPa·s. The viscosity may be 10 to 300 mPa·s or 20 to 250 mPa·s.

[0095] In some embodiments, when the viscosity is adjusted to 5 mPa·s or higher, a sufficient film thickness can be easily obtained during coating. Furthermore, when the viscosity is adjusted to 400 mPa·s or lower, a uniform film thickness can be easily obtained during coating. Therefore, by adjusting the viscosity within the above range, excellent coating properties can be easily obtained.

[0096] Here, the viscosity can be measured using, for example, an E-type viscometer manufactured by Toki Sangyo Co., Ltd. For the measurement, the measurement temperature is set to 25°C ± 0.5°C, then 1 mL to 1.5 mL of the resin composition (varnish) is placed in the viscometer, and the viscosity is recorded 10 minutes after the start of measurement. For the above measurement, a varnish in which the resin composition is dissolved in a solvent is used so that the non-volatile components (solid components) are 1 to 20%. The rotation speed during measurement is adjusted according to the viscosity category of the resin composition.

[0097] The film thickness of the primer layer-forming resin composition is not particularly limited, but may be in the range of 0.5 to 50 μm. When the film thickness is adjusted to the above range, it tends to be easier to ensure sufficient adhesion. From the viewpoint of adhesion, the above film thickness may preferably be in the range of 1 to 15 μm, and more preferably in the range of 3 to 15 μm.

[0098] In some embodiments, the elastic modulus at 35°C of the film obtained by applying and heat-drying a primer layer-forming resin composition, preferably a polyamide-imide resin composition (varnish), is preferably in the range of 0.5 to 8.0 GPa, and more preferably in the range of 1.0 to 5 GPa. The heat-drying for forming the above film can be carried out, for example, by heating at 50°C for 10 minutes and then drying at 200°C for 1 hour. The above elastic modulus is a value measured by a dynamic viscoelasticity measuring device. From the viewpoint of further improving the reliability in power semiconductor devices, it is preferable that the above film has appropriate flexibility. Therefore, in one embodiment, the elastic modulus of the above film is more preferably in the range of 2.0 GPa to 4.5 GPa.

[0099] The modulus of elasticity can be measured, for example, using the Rheogel-E4000 dynamic viscoelasticity measuring device manufactured by UBM Corporation. The modulus of elasticity is, for example, a value obtained by using a film obtained by applying and drying the above resin composition (varnish), under the conditions of a measurement frequency of 10 MHz and a measurement temperature of 35°C.

[0100] In some embodiments, the dielectric breakdown voltage of the dried film obtained by applying and heat-drying the resin composition (varnish) is preferably 50 V / μm or higher. More preferably, the dielectric breakdown voltage may be 150 V / μm or higher, and even more preferably 250 V / μm or higher. When the dielectric breakdown voltage is 50 V / μm or higher, excellent insulation can be easily obtained by applying the resin composition to a power semiconductor device.

[0101] The resin composition for forming the primer layer according to the above embodiment has excellent heat resistance and flexibility, and can therefore be suitably used not only as a primer layer but also as a constituent material for semiconductor devices. For example, the above resin composition can be used to form insulating layers, adhesive layers, protective layers, etc., in semiconductor devices, and semiconductor devices having these layers have excellent adhesion between components and excellent reliability.

[0102] Furthermore, in some embodiments, the resin composition may be used to form a primer layer in a semiconductor device not only on the sides of the semiconductor element but also at other locations. For example, it can be suitably used to form a primer layer between various components, such as between the sealing layer and the substrate, or between the sealing layer and the surface of the semiconductor element. The adhesion between these components can be evaluated, for example, by the shear strength described later.

[0103] In one embodiment, the shear strength at 200°C between members having a primer layer made of the resin composition is preferably 10 MPa or more, more preferably 15 MPa or more. If the shear strength at 200°C is 10 MPa or more, excellent adhesion can be easily obtained even when the resin composition is applied to the configuration of a power semiconductor device.

[0104] In one embodiment, in a laminate having a primer layer formed using the above resin composition and a sealing layer formed using a sealing resin composition sequentially on a substrate, the shear strength between the substrate and the sealing layer at 200°C can be 10 MPa or more. In some embodiments, the shear strength between members having a primer layer made of the above resin composition at 260°C can also be 10 MPa or more, and further can be 15 MPa or more. The above laminate can be obtained by applying and drying a resin composition (varnish) on a substrate to form a film, and then forming a sealing layer thereon using a sealing resin composition.

[0105] Shear strength can be measured using, for example, a shear strength measuring device (Nordson Advanced Technologies, Ltd. 4000 series). For measurement, a sample can be used in which a resin composition is applied and dried on a SiC substrate to form a film, and then a φ5 mm sealing resin layer is formed on top of it using an epoxy sealing resin. Typical measurement conditions are a heat stage temperature of 200°C and a probe speed of 5 mm / min. The substrate material and the sealing material constituting the sealing layer can be changed as appropriate.

[0106] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples and includes various embodiments.

[0107] Preparation of a resin composition for primer layer formation (polyamide-imide resin composition) (Synthesis Example 1) In a 1-liter four-necked flask equipped with a thermometer, stirrer, nitrogen inlet tube, and condenser with oil-water separator, 15.7 g of 9,9-bis(4-aminophenyl)fluorene, 16.5 g of 4,4'-methylenebis[2,6-bis(1-methylethyl)benzeneamine], and 2.5 g of 1,3-bis(3-aminopropyl)1,1,3,3-tetramethyldisiloxane were added under a nitrogen stream. Then, 298 g of N-methyl-2-pyrrolidone (hereinafter referred to as NMP) was added and dissolved to obtain a solution. Next, 21.1 g of trimellitic anhydride chloride (hereinafter referred to as TAC) was added to the above solution while cooling it so as not to exceed 20°C. After stirring at room temperature for 2 hours, 12.1 g of triethylamine (hereinafter referred to as TEA) was added and the mixture was reacted at room temperature for at least 15 hours to obtain a polyamic acid solution. The obtained polyamic acid solution was further reacted at 180°C for 6 hours to obtain a polyamide-imide resin solution. This polyamide-imide resin solution was poured into water, and the resulting precipitate was separated, pulverized, and dried to obtain powdered polyamide-imide resin (PAI-1). The obtained polyamide-imide resin powder (PAI-1) was soluble in a polar solvent (NMP) at room temperature (25°C). The weight-average molecular weight (Mw) of the obtained polyamide-imide resin (PAI-1) was measured using gel permeation chromatography (hereinafter referred to as GPC) on a standard polystyrene basis, and the Mw was found to be 67,000.

[0108] The GPC measurement conditions are as follows: Liquid delivery pump: LC-20AD UV-Vis detector: SPD-20A Flow rate: 1 mL / min Column temperature: 40°C Molecular weight standard: Standard polystyrene

[0109] Next, 12 g of the polyamide-imide resin powder (PAI-1) obtained above, 35 g of N-methyl-2-pyrrolidone, 52 g of butyl cellosolve acetate, and 2 g of silane coupling agent (product name "KBM-402 (3-glycidoxypropylmethyldimethoxysilane)" manufactured by Shin-Etsu Chemical Co., Ltd.) were added to a 0.5 liter four-necked flask under a nitrogen stream and stirred for 12 hours to obtain a yellow reaction mixture. The obtained yellow reaction mixture was packed into a filter KST-47 (manufactured by Advantec Co., Ltd.) and subjected to pressure filtration at a pressure of 0.3 MPa to obtain a primer layer forming resin composition (P-1).

[0110] (Synthesis Example 2) In a 1-liter four-necked flask equipped with a thermometer, stirrer, nitrogen inlet tube, and condenser with oil-water separator, 102.4 g of 2,2-bis[4-(4-aminophenoxy)phenyl]propane and 6.9 g of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane were added under a nitrogen stream, and 700 g of NMP was added to dissolve the compounds and obtain a solution. Next, 59.0 g of TAC was added to the above solution while cooling the reaction solution so that it did not exceed 20°C. After stirring at room temperature for 1 hour, 34.0 g of TEA was added while cooling the reaction solution so that it did not exceed 20°C, and the mixture was reacted at room temperature for 3 hours to produce a polyamic acid solution. The obtained polyamic acid solution was further dehydrated and condensed at 190°C for 6 hours to produce a polyamide-imide resin solution. By pouring this polyamide-imide resin varnish into water, the resulting precipitate was separated, pulverized, and dried to obtain powdered polyamide-imide resin (PAI-2). The weight-average molecular weight (Mw) of the obtained polyamide-imide resin (PAI-2) was measured using gel permeation chromatography (GPC) on a standard polystyrene basis, and the Mw was found to be 75,000. Next, 12 g of the polyamide-imide resin powder (PAI-2) obtained above, 35 g of N-methyl-2-pyrrolidone, 52 g of butyl cellosolve acetate, and 2 g of a silane coupling agent (product name "KBM-402 (3-glycidoxypropylmethyldimethoxysilane)" manufactured by Shin-Etsu Chemical Co., Ltd.) were added to a 0.5 liter four-necked flask under a nitrogen stream and stirred for 12 hours to obtain a yellow reaction mixture. The obtained yellow reaction mixture was packed into a filter KST-47 (manufactured by Advantec Co., Ltd.) and subjected to pressure filtration at a pressure of 0.3 MPa to obtain a primer layer forming resin composition (P-2).

[0111] Preparation of Semiconductor Device Test Samples (Example 1) Using the resin composition (P-1) obtained in Synthesis Example 1, test samples for semiconductor devices were prepared and their adhesion was evaluated. Specifically, first, the resin composition (P-1) was applied to a bare SiC substrate (Tank Blue, 4-inch, 4H-N, Z grade) using a spray device (Sanei Tech Co., Ltd. AXA400). Next, the coating of the resin composition (P-1) was dried at 80°C for 1 hour and then at 210°C for 1 hour to form a dry film (primer layer) with a thickness of 10 μm. Then, using epoxy encapsulating resin (CEL-420HFC) manufactured by Resonaq Co., Ltd., transfer molding was performed at 175°C / 90 sec, and a 10 mm adhesive surface was formed on the dry film. ２ A sealing resin layer was formed, and a laminate of SiC substrate / primer layer / sealing resin layer was obtained. This laminate was used as a sample for semiconductor device testing.

[0112] (Example 2) A semiconductor device test sample was prepared in the same manner as in Example 1, except that the resin composition (P-1) used in Example 1 was changed to the resin composition (P-2) synthesized in Synthesis Example 2.

[0113] (Comparative Example 1) A laminate of SiC substrate / sealing resin layer was fabricated by forming only a sealing resin layer on the bare SiC substrate used in Example 1, without providing a primer layer.

[0114] Various Evaluations <3-1> Evaluation of Primer Layer Forming Resin Compositions The primer layer forming resin compositions P-1 and P-2 obtained in Synthesis Examples 1 and 2 were evaluated for various properties as follows. (Viscosity) Viscosity measurements were performed on the primer layer forming resin compositions P-1 and P-2 obtained in Synthesis Examples 1 and 2 using a viscometer, Type E, manufactured by Toki Sangyo Co., Ltd. The measurement conditions were as follows: Sampling amount: 1.1 ml, Measurement temperature: 25°C, Cone rotation speed: 10 rpm, Measurement time: 10 minutes. The measurement results are shown in Table 1.

[0115] (Glass transition temperature and elastic modulus) Resin compositions P-1 and P-2 obtained in Synthesis Examples 1 and 2 were coated onto a substrate using a bar coater and then heat-dried to obtain a dry film with a thickness of 10 μm. The heat drying to form the above dry film was carried out under the conditions of heating at 80°C for 10 minutes followed by drying at 210°C for 1 hour. The dry films obtained as described above were used as measurement samples, and the following measurements were performed. The measurement samples were placed in a dynamic viscoelasticity analyzer (Rheogel-E4000) manufactured by UBM Corporation, and the glass transition temperature of each dry film of resin composition P-1 and P-2 was measured. The measurement was carried out under the conditions of a chuck distance of 20 mm and a heating rate of 3°C / min, and the glass transition temperature (Tg) was obtained from the peak position of tanδ. The measured values ​​are shown in Table 1. In addition, the elastic modulus was measured using the dry films prepared in the same manner. The measured values ​​at a temperature of 35°C and a measurement frequency of 10 MHz are shown in Table 1.

[0116] (Coefficient of Linear Expansion) Resin compositions P-1 and P-2 obtained in Synthesis Examples 1 and 2 were coated onto a substrate using a bar coater and then heat-dried to obtain a dry film with a thickness of 10 μm. The heat-drying to form the dry film was carried out under the conditions of heating at 80°C for 10 minutes followed by drying at 210°C for 1 hour. The dry film obtained as described above was used as a sample for measurement, and the coefficient of linear expansion (CTE) was measured. The measurement was performed using a thermomechanical analyzer (TMA, Hitachi High-Tech Science Corporation "SS7100") under the conditions of a chuck distance of 10 mm, a load of 10 g, and a heating rate of 10°C / min. The displacements at 70°C and 140°C were connected by a straight line, and the value calculated from the slope of the line was taken as the CTE value.

[0117] <3-2> Evaluation of Semiconductor Device Test Samples (Adhesion) The semiconductor device test samples of Examples 1 and 2 and Comparative Example 1 were set on the heat stage of a shear strength measuring device, and the shear strength values ​​were measured. A Nordson Advanced Technology 4000 series was used as the shear strength measuring device. The measurements were performed at temperatures of 25°C, 200°C, and 260°C, with a probe speed of 5 mm / min. The measurement results are shown in Table 1.

[0118]

[0119] As is clear from the comparison between Examples 1 and 2 and Comparative Example 1, it can be seen that the shear strength (adhesion between components) can be improved by providing a primer layer. In particular, it can be seen that the heat resistance is improved when the dried film of the resin composition (primer layer) has a glass transition temperature (Tg) of over 200°C, thereby easily maintaining adhesion even at high temperatures of 200°C. Especially in Example 2, which used a resin composition with a Tg of over 300°C, it has excellent shear strength exceeding 15 MPa even at high temperatures of 260°C. Therefore, according to the embodiments of the present invention, by having a primer layer on at least the side surface of the semiconductor element, the peeling of the encapsulation layer that tends to occur on the side surface of the semiconductor element can be improved, and the same effect can be obtained in the configuration of power semiconductors. As a result, peeling of the encapsulation layer, such as that seen during reflow testing, is suppressed, and it becomes possible to provide highly reliable semiconductor devices.

[0120] 1. Substrate 1A. Lead frame 1a. Die pad 1b. Lead 2, 2A, 2B. Semiconductor element 2a. Side of semiconductor element 2b. Top surface (surface) of semiconductor element 3. Encapsulation layer (encapsulation resin layer) 4. Primer layer 4a. Primer layer located on the side of the semiconductor element 4b. Primer layer located on the top surface of the semiconductor element 5. Wire 10. Semiconductor device

Claims

1. A semiconductor device comprising: a semiconductor element mounted on a substrate; a sealing layer that encapsulates the semiconductor element; and a primer layer formed using a primer layer forming resin composition and covering at least the side surface of the semiconductor element.

2. The semiconductor device according to claim 1, wherein the primer layer forming resin composition comprises at least one resin selected from the group consisting of polybenzoxazole, polyamide, polyamideimide, and polyimide.

3. The semiconductor device according to claim 1 or 2, wherein the glass transition temperature of the resin composition for forming the primer layer is 200°C or higher.

4. The semiconductor device according to any one of claims 1 to 3, wherein the coefficient of linear expansion of the primer layer forming resin composition at 70 to 140°C is 25 to 120 ppm / °C.

5. The semiconductor device according to any one of claims 1 to 4, wherein the semiconductor element includes at least one selected from the group consisting of a Si semiconductor element, a SiC semiconductor element, and a GaN semiconductor element.

6. The semiconductor device according to any one of claims 1 to 5, wherein the semiconductor element has a bare surface exposed by dicing the wafer.

7. The semiconductor device according to any one of claims 1 to 6, wherein the sealing layer is a cured product of a sealing resin composition containing an epoxy resin.

8. The semiconductor device according to any one of claims 1 to 7, wherein two or more semiconductor elements are mounted perpendicular to the substrate.

9. A resin composition for forming a primer layer, used to form a primer layer provided between the side surface of a semiconductor device and the sealing layer.

10. A resin composition for forming a primer layer according to claim 9, wherein a laminate is formed by joining a semiconductor element and a sealing layer formed using a resin composition for sealing via a primer layer formed using the resin composition for forming a primer layer, and the shear strength between the semiconductor element and the sealing layer at 200°C is 10 MPa or more.

11. The primer layer forming resin composition according to claim 9 or 10, wherein the viscosity at 25°C, as measured using an E-type viscometer, is 13,000 mPa·s or less.

12. A method for manufacturing a semiconductor device, comprising the steps of: forming a primer layer on at least the side surface of a semiconductor element mounted on a substrate using a primer layer forming resin composition; and forming a sealing layer that covers the semiconductor element and the primer layer using a sealing resin composition.

13. A method for manufacturing a semiconductor device according to claim 12, further comprising a step of mounting semiconductor elements on a substrate, wherein in the step, two or more semiconductor elements are mounted perpendicular to the substrate.

14. The method for manufacturing a semiconductor device according to claim 13, wherein, in the step of forming the primer layer, each side surface of two or more semiconductor elements mounted on the substrate is collectively coated with the primer layer forming resin composition.

15. A method for manufacturing a semiconductor device, comprising the steps of: forming a primer layer on the side surface of a semiconductor element using a primer layer forming resin composition; mounting the semiconductor element with the primer layer formed on its side surface onto a substrate; and forming a sealing layer that covers the semiconductor element and the primer layer using a sealing resin composition.

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