Bonding film, semiconductor device, and method for manufacturing semiconductor device

Abstract

A semiconductor device with excellent electrical connection reliability can be obtained even if the pitch between electrodes is narrow. An adhesive film for joining a semiconductor element to a semiconductor element or joining a semiconductor element to a circuit substrate has a width of a temperature region exhibiting a melt viscosity of 50,000 Pa·s or less in a temperature range of greater than 90°C and less than 200°C that is 40°C or greater and less than 110°C, and a ratio (V2 / V1) of a melt viscosity V2 at 200°C to a lowest melt viscosity V1 in the temperature range of greater than 90°C and less than 200°C is greater than 1.0.

Description

Technical Field

[0001] This invention relates to adhesive films, semiconductor devices, and methods for manufacturing semiconductor devices. Background Technology

[0002] In the manufacturing process of semiconductor devices, as a mounting method for bonding a pair of electronic components (semiconductor component and circuit board, or semiconductor component and semiconductor component), a mounting method using an adhesive film is known. In this mounting method, one electronic component is electrically connected to the other electronic component by heating and pressurizing the adhesive film while it is positioned between the pair of electronic components (for example, see Patent Documents 1, 2, etc.). Existing patent literature Patent documents

[0003] Patent Document 1: Japanese Patent Application Publication No. 2021-119245 Patent Document 2: Japanese Patent Application Publication No. 2017-145289 Summary of the Invention The technical problem that the invention aims to solve

[0004] On the other hand, in recent years, in order to process and transmit larger amounts of data quickly and efficiently, there has been a demand to increase the number of interconnections between semiconductor elements constituting a semiconductor device or between semiconductor elements and a circuit board, while shortening wiring distances. To this end, it is necessary to not only narrow the spacing between electrodes such as bumps disposed on the surface of semiconductor elements or circuit boards, but also to further ensure the reliability of electrical connections between electrodes.

[0005] The present invention was made in view of the above circumstances, and its technical problem is to provide an adhesive film, a semiconductor device manufactured using the adhesive film, and a method for manufacturing the semiconductor device, wherein the adhesive film can obtain a semiconductor device with excellent electrical connection reliability even when the spacing between electrodes is narrow. Technical means to solve technical problems

[0006] The above-mentioned technical problem is solved by the following invention. That is: The adhesive film of the present invention is used for bonding semiconductor elements to semiconductor elements or bonding semiconductor elements to circuit boards. It exhibits a temperature range with a melt viscosity of less than 50,000 Pa·s in a temperature range greater than 90°C and less than 200°C, with a width of 40°C or more and less than 110°C. The ratio (V2 / V1) of the melt viscosity V2 at 200°C to the lowest melt viscosity V1 in the temperature range greater than 90°C and less than 200°C is greater than 1.0.

[0007] In one embodiment of the adhesive film of the present invention, the melt viscosity V2 is preferably 8000 Pa·s or higher.

[0008] In other embodiments of the adhesive film of the present invention, the preferred film thickness is 0.5 μm to 6 μm.

[0009] In other embodiments of the adhesive film of the present invention, the preferred film thickness is 0.5 μm to 2.5 μm.

[0010] In other embodiments of the adhesive film of the present invention, the circuit substrate is preferably a substrate on which a circuit is formed on a silicon substrate or a substrate on which a circuit is formed on a glass substrate.

[0011] In other embodiments of the adhesive film of the present invention, the material constituting the surface of the electrode disposed on the semiconductor element is preferably a metallic material comprising at least one element selected from the group consisting of Au and Sn as a main component.

[0012] In other embodiments of the adhesive film of the present invention, the electrodes disposed on the semiconductor element preferably have a maximum diameter of 0.5 μm to 5 μm.

[0013] In other embodiments of the adhesive film of the present invention, the electrode spacing of the electrodes disposed on the semiconductor element is preferably 0.5 μm to 5 μm.

[0014] In other embodiments of the adhesive film of the present invention, the material constituting the surface of the electrode disposed on the circuit board is preferably a metallic material comprising at least one element selected from the group consisting of Au and Sn as a main component.

[0015] In other embodiments of the adhesive film of the present invention, the maximum diameter of the electrodes disposed on the circuit board is preferably 0.5 μm to 5 μm.

[0016] In other embodiments of the adhesive film of the present invention, the electrode spacing of the electrodes disposed on the circuit board is preferably 0.5 μm to 5 μm.

[0017] Other embodiments of the adhesive film of the present invention preferably include thermosetting resins and thermoplastic resins.

[0018] In other embodiments of the adhesive film of the present invention, the thermosetting resin preferably comprises polyphenylene ether resin as the main component.

[0019] In other embodiments of the adhesive film of the present invention, the thermoplastic resin preferably contains a styrene-based elastomer as the main component.

[0020] Other embodiments of the adhesive film of the present invention preferably do not contain fillers.

[0021] The semiconductor device of the first aspect of the present invention includes: a first semiconductor element having an electrode; a second semiconductor element having an electrode and the electrode being directly connected to the electrode of the first semiconductor element; and a cured product of the adhesive film of the present invention disposed between the first semiconductor element and the second semiconductor element.

[0022] A method for manufacturing a semiconductor device according to a first aspect of the present invention includes: a step of attaching an adhesive film of the present invention to an electrode mounting surface on which an electrode of a first semiconductor element is disposed; and a step of heating and pressurizing a laminate in which the first semiconductor element, the adhesive film, and the second semiconductor element are sequentially stacked, by contacting the side of the adhesive film opposite to the side on which the first semiconductor element is disposed with the electrode mounting surface on which the electrode of the second semiconductor element is disposed, with the electrodes of the first semiconductor element facing each other.

[0023] The semiconductor device of the second aspect of the present invention comprises: a semiconductor element having electrodes; a circuit board having electrodes and the electrodes being directly connected to the electrodes of the semiconductor element; and a cured form of the adhesive film of the present invention disposed between the semiconductor element and the circuit board.

[0024] A method for manufacturing a semiconductor device according to a second aspect of the present invention includes: a step of attaching the adhesive film of the present invention to an electrode mounting surface on which electrodes of a semiconductor element are disposed; and a step of heating and pressurizing a laminate in which the semiconductor element, the adhesive film, and the circuit board are sequentially stacked, by contacting the side of the adhesive film opposite to the side on which the semiconductor element is disposed with the electrode mounting surface on which the electrodes of the circuit board are disposed, with the electrodes of the semiconductor element facing each other.

[0025] A method for manufacturing a semiconductor device according to a third aspect of the present invention includes: a step of attaching the adhesive film of the present invention to an electrode mounting surface on which electrodes of a circuit board are disposed; and a step of heating and pressurizing a laminate in which the semiconductor element, the adhesive film, and the circuit board are sequentially stacked, by contacting the side of the adhesive film opposite to the side on which the circuit board is disposed with the electrode mounting surface on which the electrodes of the semiconductor element are disposed, with the electrodes of the circuit board facing each other. Beneficial effects

[0026] According to the present invention, an adhesive film, a semiconductor device manufactured using the adhesive film, and a method for manufacturing the semiconductor device are provided, wherein the adhesive film can produce a semiconductor device with excellent electrical connection reliability even when the spacing between electrodes is narrow. Detailed Implementation

[0027] In the manufacturing process of semiconductor devices, the adhesive film of this embodiment is used for bonding semiconductor elements to each other or bonding semiconductor elements to a circuit board. Furthermore, the adhesive film of this embodiment exhibits a melt viscosity of 50,000 Pa·s or less over a temperature range greater than 90°C and less than 200°C, with a width of 40°C or more and less than 110°C, and a ratio (V2 / V1) of melt viscosity V2 at 200°C to the lowest melt viscosity V1 in the temperature range greater than 90°C and less than 200°C is greater than 1.0. Therefore, if the adhesive film of this embodiment is used, a semiconductor device with excellent electrical connection reliability can be obtained even with narrow electrode spacing. The reasons for achieving this effect are as follows.

[0028] First, the surfaces of electrodes disposed on semiconductor elements or circuit boards are generally made of an alloy material containing Au or Sn, or these metallic elements as the main component. Therefore, when electronic components are electrically bonded to each other, in other words, when electrodes are bonded to each other, bonding is achieved through the interdiffusion of the metallic elements constituting the electrode surfaces. Furthermore, bonding using such interdiffusion of metallic elements requires a heat treatment at approximately 240°C to 250°C.

[0029] Here, (i) in the process of bonding a pair of electronic components (semiconductor components with semiconductor components, or semiconductor components with a circuit board) (i.e., the process of heating from near room temperature to a temperature range (around 240°C to 250°C) where the electrodes bond due to the interdiffusion of metallic elements), the adhesive film needs to be temporarily transformed from a solid state to a sufficiently fluid paste or liquid state by heating so that it can be quickly extruded from between the connected electrodes. This is because, when a pair of electronic components is bonded in this way, it prevents the cured adhesive film from remaining between the electrodes, thereby ensuring the reliability of the electrical connection. (ii) Furthermore, within the temperature range (around 240°C to 250°C) where the electrodes bond due to the interdiffusion of metallic elements, the adhesive film must have been completely cured by the curing reaction (i.e., the adhesive film has been transformed back into a solid state (cured product) by thermal curing). In other words, the curing reaction of the adhesive film must begin in a temperature range relatively lower than the temperature range of around 240°C to 250°C.

[0030] On the other hand, in order to narrow the spacing between electrodes, it is necessary to reduce the size of the electrodes, specifically, to reduce the maximum diameter of the electrodes. Here, the maximum diameter of the electrode refers to the maximum length of the electrode in the direction parallel to the surface of the electrode on which the semiconductor element or circuit board is disposed (electrode placement surface).

[0031] Furthermore, if the size of the electrodes is reduced, the contact area between the connected electrodes becomes smaller when joining a pair of electronic components (semiconductor components to semiconductor components, or semiconductor components to circuit boards). Therefore, (iii) even when the spacing between the electrodes is narrowed, in order to make the connection between the electrodes via the narrow contact area more reliable, it is even more necessary to remove the adhesive film more reliably from between the electrodes when joining a pair of electronic components.

[0032] Based on the required properties of the adhesive film described in (i) to (iii) above, the adhesive film of this embodiment exhibits a temperature range with a melt viscosity of less than 50,000 Pa·s within a temperature range greater than 90°C and less than 200°C, with a width of 40°C or more and less than 110°C, and a ratio (V2 / V1) of melt viscosity V2 at 200°C to the lowest melt viscosity V1 within the temperature range greater than 90°C and less than 200°C is greater than 1.0.

[0033] First, if the width of the temperature region exhibiting a melt viscosity of 50,000 Pa·s or less within a temperature range greater than 90°C and less than 200°C is set to 40°C or more, the effects described in (a) and (b) below are expected to occur. Specifically, (a) if the melt viscosity is 50,000 Pa·s or less, the adhesive film will have sufficient fluidity due to paste-like or liquefied consistency. Therefore, during the heating and pressurization process with the adhesive film positioned between a pair of electronic components, the adhesive film can be extruded and removed from between the connected pair of electrodes. (b) Furthermore, if the width of the temperature region exhibiting a melt viscosity of 50,000 Pa·s or less is 40°C or more, sufficient time can be ensured to extrude and completely remove the adhesive film from between the pair of electrodes. As a result, even when the spacing between the electrodes is narrowed, it is extremely easy to ensure the connection between the electrodes via a narrow contact surface.

[0034] Furthermore, to more effectively utilize the effects described in (b) above, the width of the temperature zone is preferably 50°C or more, more preferably 60°C or more, and even more preferably 70°C or more; in fact, the wider the temperature zone, the better. However, if the width of the temperature zone is too large, when the adhesive film is exposed to a high-temperature environment during storage or transportation, the heat resistance may easily decrease, or the starting temperature of the curing reaction (meaning an increase in melt viscosity) may shift to a higher temperature side. This could lead to insufficient curing of the adhesive film even within the temperature zone (around 240°C to 250°C) where the electrodes bond together due to the interdiffusion of metal elements. From this practical point of view, the width of the temperature zone needs to be set to less than 110°C, preferably less than 100°C, and more preferably less than 90°C.

[0035] Furthermore, the ratio (V2 / V1) of the melt viscosity V2 at 200°C to the lowest melt viscosity V1 in the temperature range greater than 90°C and less than 200°C is greater than 1.0. This means that during the heating process, the melt viscosity of the adhesive film tends to increase at a higher temperature of 200°C compared to the temperature range exhibiting the lowest melt viscosity V1 (greater than 90°C and less than 200°C). In other words, it means that the curing reaction of the adhesive film has begun and is proceeding. Therefore, when the temperature range (around 240°C to 250°C) where the electrodes are joined by the interdiffusion of metal elements is reached, the adhesive film is considered to have been sufficiently cured by the curing reaction. Therefore, the phenomenon that occurs in the temperature range below which the electrodes are joined (the state in which the fluidized adhesive film is squeezed out and removed between a pair of electrodes) is stably maintained and fixed within the temperature range where the electrodes are joined. In addition, from the same point of view, the melt viscosity V2 is preferably 8000 Pa·s or more, more preferably 10000 Pa·s or more, and even more preferably 20000 Pa·s or more.

[0036] Furthermore, when the temperature range (around 240°C to 250°C) where the electrodes bond due to the interdiffusion of metallic elements is reached, from the viewpoint of sufficiently maximizing the curing of the adhesive film, V2 / V1 is preferably 1.001 or higher, more preferably 1.01 or higher, and even more preferably 1.02 or higher. Moreover, from the above viewpoint, a larger V2 / V1 is better, but if it is too large, the curing reaction (which increases melt viscosity) tends to begin in a temperature range far below 200°C, which may make it difficult to set the width of the temperature range exhibiting a melt viscosity of 50,000 Pa·s or less in the temperature range greater than 90°C and less than 200°C at 40°C or higher. Therefore, the upper limit of V2 / V1 is preferably 20 or less, more preferably 10 or less, and even more preferably 3 or less. Furthermore, from the same viewpoint, the melt viscosity V2 is preferably 100,000 Pa·s or less, more preferably 80,000 Pa·s or less, and even more preferably 60,000 Pa·s or less.

[0037] In addition, the adhesive film of this embodiment is in a solid state (non-flowing state) near room temperature (25°C). However, considering the temperature changes that are usually expected in the environment during storage or transportation, from the viewpoint of operability or quality maintenance, it is preferable to be in a solid state in the temperature range of near room temperature to 80°C, and it is even more suitable to be in a solid state in the temperature range of near room temperature to 90°C.

[0038] On the other hand, when using an adhesive film to electrically connect a pair of electronic components (semiconductor components to semiconductor components, or semiconductor components to a circuit board), space (gap) needs to be left between the pair of electronic components for inserting the adhesive film. Therefore, in the electrodes of the pair of electronic components, at least one of the electrodes needs to be a convex electrode (bump) that protrudes relative to the surface surrounding the electrode. That is, the combination of the electrode of one electronic component and the electrode of the other electronic component as the electrical connection can be selected as (i) a bump-bump combination or (ii) a bump-pad combination (an electrode composed of a flat surface flush with the surface surrounding the electrode).

[0039] Furthermore, if the maximum diameter of the bump is reduced to minimize the spacing between electrodes, the height of the bump must also be reduced to some extent, inevitably leading to a smaller gap between the pair of electronic components. In addition, from the viewpoint of shortening the wiring distance within the semiconductor device, the space (gap) for inserting the adhesive film between the pair of electronic components is also better the narrower it is. Therefore, from the viewpoint of selecting the thickness of the adhesive film in accordance with the minimization of the gap between the pair of electronic components, the adhesive film in this embodiment preferably has a thickness of 0.5 μm to 6 μm, more preferably 0.5 μm to 4 μm, even more preferably 0.5 μm to 2.5 μm, and particularly preferably 0.5 μm to 1.5 μm. When the thickness of the adhesive film is greater than 6 μm, when using the adhesive film to bond a pair of electronic components, cured adhesive film residue can easily remain between the electrodes of one electronic component and the electrodes of the other electronic component, potentially leading to a decrease in the electrical connection reliability of the semiconductor device.

[0040] On the other hand, considering the need to minimize the electrode spacing and shorten wiring distances, a smaller adhesive film thickness is preferable; in this sense, there is no lower limit to the thickness. However, drastically minimizing the electrode spacing or shortening the wiring distance also means that the gap between a pair of electrically connected electronic components becomes extremely narrow. In this case, tiny foreign objects such as dust present in the semiconductor device manufacturing environment (cleanroom) can enter the gap between the pair of electronic components, easily leading to a decrease in the electrical connection reliability of the semiconductor device. As a countermeasure to this problem, increasing the cleanliness of the cleanroom can be cited. However, it is difficult to completely remove tiny foreign objects of a size that cause a decrease in the electrical connection reliability of the semiconductor device, and the cost of ensuring and maintaining a high-cleanliness environment is also high, so the above countermeasure is not practical. Therefore, even when minimizing the electrode spacing or shortening the wiring distance, it is necessary to pay attention to the balance of semiconductor device manufacturing costs and avoid an extremely narrow gap between a pair of electronic components. Based on this practical situation, it can be said that the lower limit of the adhesive film thickness in this embodiment is preferably 0.5 μm or more.

[0041] The adhesive film of this embodiment can be used for bonding semiconductor elements to semiconductor elements or for bonding semiconductor elements to circuit boards. However, from the viewpoint that more electrical connection points can be provided in a semiconductor device, while shortening the wiring distance, and thus enabling a semiconductor device with three-dimensional integration of semiconductor elements, it is particularly suitable to use the adhesive film of this embodiment for bonding semiconductor elements to semiconductor elements.

[0042] The semiconductor element used for bonding can be a wafer-shaped semiconductor element or a chip-shaped semiconductor element obtained by monolithizing a wafer-shaped semiconductor element through dicing or the like. Examples of bonding semiconductor elements to each other include bonding wafer-shaped semiconductor elements to each other or bonding chip-shaped semiconductor elements to wafer-shaped semiconductor elements. Furthermore, when bonding semiconductor elements to a circuit board, either wafer-shaped semiconductor elements or chip-shaped semiconductor elements can be used as the semiconductor element.

[0043] As the circuit board, known circuit boards can be used. Besides the widely used glass epoxy board with circuits formed on it (glass epoxy circuit board), boards with circuits formed on a silicon substrate (silicon circuit board) and boards with circuits formed on a glass substrate (glass circuit board) can also be used. However, glass epoxy circuit boards contain a large amount of easily deformable resin material, making warpage and unevenness of the board more likely. Therefore, in the bonding of semiconductor elements to the glass epoxy circuit board, if the electrode spacing is reduced, the non-uniformity of the gap formed between the semiconductor element and the glass epoxy circuit board tends to increase. In this case, if the adhesive film of this embodiment with a thickness of 1 μm or less is used to bond the semiconductor element to the glass epoxy circuit board, the reliability of the electrical connection tends to decrease. Based on these points, when using the adhesive film of this embodiment for bonding semiconductor elements to the glass epoxy circuit board, the thickness of the adhesive film is preferably greater than 1 μm and less than 6 μm, more preferably 1.5 μm to 6 μm, and even more preferably 2 μm to 6 μm. On the other hand, compared to glass epoxy circuit boards, silicon or glass circuit boards, which are made solely of inorganic materials that are less deformable than resin materials, exhibit minimal warpage or undulation. Consequently, the non-uniformity of the gaps formed between semiconductor elements and the silicon or glass circuit boards is also very small. Therefore, when the adhesive film of this embodiment is used for bonding these circuit boards to semiconductor elements, its thickness can be appropriately selected within the range of 0.5 μm to 6 μm. Based on these factors, silicon or glass circuit boards are suitable as circuit boards for bonding semiconductor elements to circuit boards.

[0044] Furthermore, the electrodes provided on the semiconductor element and circuit board used in the bonding process of the adhesive film of this embodiment have the following specifications. First, the material constituting the surface of the electrode provided on the semiconductor element or circuit board (the part that can become the connection surface with other electrodes) is made of a metallic material, which contains at least one element selected from the group consisting of Au and Sn as a main component. Here, "main component" means that the content of Au or Sn in the metallic material is 50 atomic% or more, preferably 80 atomic% or more, more preferably 90 atomic% or more, and particularly preferably the material constituting the electrode surface is composed of only Au or only Sn. In addition, the metallic materials constituting the electrode surface and the interior can be different, but it is generally preferred that the material constituting the electrode surface and the material constituting the interior are the same.

[0045] Furthermore, from the viewpoint of easily minimizing the spacing between electrodes, the maximum diameter of the electrodes is preferably 0.5 μm to 5 μm, more preferably 0.5 μm to 2 μm. Further, from the viewpoint of minimizing the spacing between electrodes, the spacing between electrodes is preferably 0.5 μm to 5 μm, more preferably 0.5 μm to 2.5 μm, and even more preferably 0.5 μm to 1.5 μm. Additionally, the spacing between electrodes refers to the shortest distance between the center point of one electrode and the center point of the other electrode closest to it, centered at the bisection of the maximum diameter of the electrodes. Furthermore, the planar shape of the electrodes is not particularly limited; for example, polygons, circles, ellipses, etc., are possible. When the electrode is a protrusion, a circle or a polygon is preferred (but it must be a polygon with a planar shape closer to a circle, such as a hexagon or octagon). Furthermore, the cross-sectional shape of the protrusion (the cross-sectional shape in a plane orthogonal to the electrode placement surface) is not particularly limited as long as it is convex; it is generally semi-circular, approximately semi-circular, arc-shaped, rectangular, or square. However, from the viewpoint of preventing a decrease in electrical connection reliability due to the inclusion of minute foreign objects between bumps or between a bump and a pad when joining a pair of electronic components, the cross-sectional shape of the bumps is particularly preferably semi-circular or approximately semi-circular. This also applies when the adhesive film in this embodiment contains filler.

[0046] The adhesive film of this embodiment is not particularly limited in its constituent materials as long as it is composed of a thermosetting resin composition, but it is preferable to include at least a thermosetting resin and a thermoplastic resin. Furthermore, the adhesive film and its cured product of this embodiment, used for manufacturing semiconductor devices with excellent electrical connection reliability, are non-conductive.

[0047] (A) Thermosetting resin As a thermosetting resin, any known thermosetting resin can be used without particular restrictions, such as polyphenylene ether resin, polyimide resin, maleimide resin, etc. Furthermore, the thermosetting resin incorporated in the thermosetting resin composition can be a single type or a combination of two or more types. Among these thermosetting resins, polyphenylene ether resin is preferred from the viewpoint of the dielectric properties, heat resistance, and mechanical properties of the cured adhesive film, or the electrical connection reliability of semiconductor devices manufactured using the adhesive film. Examples of polyphenylene ether resins include modified polyphenylene ether resins modified by introducing reactive groups such as styrene groups or methacrylic groups at the ends of the molecules. Examples include styrene-modified polyphenylene ether resins (commercially available products, such as OPE-2st-1200 and OPE-2st-2200 manufactured by Mitsubishi Gas Chemical Co., Ltd.) and methacrylic acid-modified polyphenylene ether resins (commercially available products, such as Noryl SA-9000 manufactured by SABIC Corporation). Furthermore, from the viewpoint of ensuring and improving the formability of the adhesive film and ensuring and improving its solubility in the solvent contained in the coating liquid used to form the adhesive film, the number average molecular weight of the polyphenylene ether resin or other thermosetting resin is preferably 500 to 5000, more preferably 800 to 3500, and even more preferably 1000 to 2500.

[0048] Furthermore, relative to all the resin components contained in the thermosetting resin composition, the content of the thermosetting resin is preferably 10% to 65% by mass, more preferably 15% to 60% by mass, and even more preferably 20% to 50% by mass. Additionally, the thermosetting resin preferably contains at least polyphenylene ether resin, more preferably as a main component. Here, "main component" means a content of 50% by mass or more relative to the total amount of thermosetting resin. Relative to all the thermosetting resin contained in the thermosetting resin composition, the proportion of polyphenylene ether resin is preferably 70% to 100% by mass, more preferably 90% to 100% by mass, and most preferably 100% by mass. By formulating the resin components as described above, the electrical connection reliability of semiconductor devices manufactured using adhesive films can be easily and reliably ensured.

[0049] (B) Thermoplastic resin As for thermoplastic resins, any known thermoplastic resin can be used without particular restrictions, such as styrene-based elastomers, acrylic rubbers, and fluoropolymers. Furthermore, the thermoplastic resin incorporated into the thermosetting resin composition can be a single type or a combination of two or more types. Among these thermoplastic resins, styrene-based elastomers are preferred from the viewpoint of the dielectric properties and heat resistance of the cured adhesive film. Commercially available styrene-based elastomers include, for example, Asahi Kasei's "Tuftec H1221" (hydrogenated styrene-based thermoplastic elastomer) and ENEOS Materials Co., Ltd.'s "TR2003" (styrene-based thermoplastic elastomer).

[0050] Furthermore, relative to all the resin components contained in the thermosetting resin composition, the proportion of thermoplastic resin is preferably 35% to 90% by mass, more preferably 40% to 85% by mass, and even more preferably 50% to 80% by mass. In addition, the thermoplastic resin preferably contains at least a styrene-based elastomer, more preferably a styrene-based elastomer as a main component. Here, "main component" means a proportion of 50% by mass or more relative to the total amount of thermoplastic resin. Relative to all the thermoplastic resin contained in the thermosetting resin composition, the proportion of styrene-based elastomer is preferably 70% to 100% by mass, more preferably 90% to 100% by mass, and most preferably 100% by mass.

[0051] (C) Other ingredients In the thermosetting resin composition constituting the adhesive film, in addition to the resin material, fillers, curing catalysts, reducing agents, ion scavengers, leveling agents, antioxidants, defoamers, flame retardants, colorants, reactive diluents, etc., may be appropriately added as needed. The content ratio of other components (total amount) in the thermosetting resin composition is not particularly limited and can be appropriately selected according to the type of other components and their intended use. Generally, it is preferred to be greater than 0% by mass and less than 20% by mass, more preferably greater than 0% by mass and less than 10% by mass, and even more preferably greater than 0% by mass and less than 5% by mass.

[0052] Here, "filler" means a material that (i) is in particulate form and (ii) does not dissolve in any of the remaining components of the thermosetting resin composition constituting the adhesive film, excluding the filler, and does not soften due to reaction with the remaining components; representative examples include inorganic fillers, organic fillers, and organic-inorganic composite fillers composed of organic and inorganic materials. Furthermore, even materials not labeled as "filler," in other words, materials intended for purposes other than filling, are included in "filler" as long as they meet the conditions described in (i) and (ii) above. Examples of such materials include titanium dioxide used as a white pigment.

[0053] Furthermore, regarding fillers, when bonding a pair of electronic components, if the adhesive film cures while fillers are present between the electrodes, it may lead to a decrease in the reliability of the electrical connection. In particular, if the gap length between a pair of electronic components is reduced from the viewpoint of minimizing the distance between electrodes or shortening the wiring distance, the filler, like tiny foreign objects, can easily become a cause of decreased electrical connection reliability in the semiconductor device due to its entry into the gap between the pair of electronic components. From this viewpoint, the thermosetting resin composition constituting the adhesive film preferably contains no fillers at all. Even when the thermosetting resin composition contains fillers, from the viewpoint of suppressing a decrease in electrical connection reliability, the content is preferably greater than 0% by mass and less than 5% by mass, more preferably greater than 0% by mass and less than 2% by mass, and even more preferably greater than 0% by mass and less than 1% by mass. Furthermore, from the same viewpoint, the volume average particle size D95 (the particle size that accounts for 95% of the total particle size distribution from the small diameter side in the volume-based particle size distribution) of the filler contained in the thermosetting resin composition is preferably 0.2 times or less than the thickness of the adhesive film, more preferably 0.1 times or less. In addition, when the filler is a monodisperse filler without a particle size distribution, the particle size of the filler is preferably 0.2 times or less than the thickness of the adhesive film, more preferably 0.1 times or less.

[0054] As a curing catalyst, known curing catalysts can be used, specifically including organic peroxides, inorganic peroxides, azo compounds, imidazole compounds, etc. From the viewpoint of the reactivity of thermosetting resins, organic peroxides or imidazole compounds are preferred as curing catalysts. Examples of organic peroxides include dicumyl peroxide, di(2-tert-butylperoxyisopropyl)benzene, tert-butylperoxyisopropylbenzene, benzoyl peroxide, etc. Examples of imidazole compounds include imidazole, 2-methylimidazolium, 2-ethylimidazolium, 2-ethyl-4-methylimidazolium, 2-phenylimidazolium, 4-phenylimidazolium, 1-cyanoethyl-2-phenylimidazolium, 1-(2-cyanoethyl)-2-ethyl-4-methylimidazolium, etc.

[0055] In manufacturing the adhesive film of this embodiment, a coating liquid is used, which is prepared by dissolving the constituent components of the adhesive film in a solvent. The solvent can be appropriately selected based on the solubility of each component constituting the adhesive film (excluding insoluble components such as fillers) in the solvent. Examples include methylcyclohexane, cyclohexanone, and methyl ethyl ketone (MEK). Two or more solvents can also be used in combination as needed. Furthermore, the proportion of solvent in the coating liquid is not particularly limited, as long as it can be appropriately selected to adjust the viscosity to be suitable for coating treatment. Generally, 50% to 90% by mass is preferred, and 40% to 80% by mass is even more preferred.

[0056] Then, the above-mentioned coating solution is applied to one side of a substrate film (e.g., a double-sided release-treated polyethylene terephthalate (PET) film) to form a coating layer, and the coating layer is dried to form an adhesive film. Furthermore, known coating methods such as doctor blade coating, gravure printing, and die-casting can be used as coating methods. The drying conditions for the coating layer can be appropriately selected based on the drying apparatus used, the boiling point and content of the solvent in the coating solution, and the thickness of the coating layer. For example, if a drying oven is used to dry the coating layer, the drying temperature can be 80°C to 120°C, and the drying time can be 5 minutes to 20 minutes. Additionally, a protective film (e.g., a double-sided release-treated PET film) is usually preferably adhered to the surface of the dried adhesive film. Therefore, when used, the adhesive film of this embodiment is generally preferably provided as a multilayer film containing the adhesive film, such as a laminate in which a substrate film, an adhesive film, and a protective film are sequentially stacked. In this case, during the manufacturing of a semiconductor device using the adhesive film of this embodiment, other films (substrate film, protective film, etc.) other than the adhesive film are peeled off from the multilayer film at an appropriate time.

[0057] Next, a semiconductor device manufactured using the adhesive film of this embodiment and a method thereof will be described.

[0058] The semiconductor device of the first aspect of this embodiment includes: a first semiconductor element having an electrode; a second semiconductor element having an electrode and the electrode being directly connected to the electrode of the first semiconductor element; and a cured product of the adhesive film of this embodiment disposed between the first semiconductor element and the second semiconductor element. Here, "direct connection" means a state in which the electrode of the first semiconductor element and the electrode of the second semiconductor element are electrically connected without direct contact via wires or wiring. Furthermore, in the semiconductor device of the first aspect of this embodiment, at least one of the electrodes provided on the first semiconductor element and the electrodes provided on the second semiconductor element is a bump, while the other electrode can be either a bump or a pad.

[0059] Furthermore, the semiconductor device of the first aspect of this embodiment is manufactured by at least the bonding process and the heating and pressurizing process described below.

[0060] Bonding process: The bonding process is the process of bonding the adhesive film of this embodiment to the electrode mounting surface of the electrode on which the first semiconductor element is disposed. When performing the bonding process, for example, a laminator or the like can be used to bond the adhesive film to the electrode mounting surface of the first semiconductor element.

[0061] Heating and pressurizing process: The heating and pressurizing process involves heating and pressurizing a laminate in which a first semiconductor element, an adhesive film, and a second semiconductor element are sequentially stacked. Here, the laminate is formed by bringing the side of the adhesive film opposite to the side where the first semiconductor element is located into contact (bonding) with the electrode surface of the electrode of the second semiconductor element, with the electrodes of the first semiconductor element facing each other. The heating and pressurizing process is typically performed using a flip-chip bonder. Furthermore, the heating conditions can be appropriately selected to ensure the adhesive film cures and creates a bond between the electrodes due to the interdiffusion of metallic materials. For example, the heating temperature can be appropriately selected to be around 250°C to 300°C, and the heating time can be appropriately selected to be between several seconds and several minutes.

[0062] After the heating and pressurizing process is completed, various subsequent processes (e.g., cutting, back-side grinding, formation of redistribution layers, etc.) can be performed as needed. Furthermore, in the case where the semiconductor device of the first aspect of this embodiment is a semiconductor device that integrates semiconductor elements in three dimensions, the bonding process and the heating and pressurizing process can be performed as a cycle, and this cycle can be repeated multiple times. Alternatively, other processes can be performed appropriately between each cycle as needed.

[0063] Furthermore, the semiconductor device of the second aspect of this embodiment includes: a semiconductor element having electrodes; a circuit board having electrodes and the electrodes being directly connected to the electrodes of the semiconductor element; and a cured form of the adhesive film of this embodiment disposed between the semiconductor element and the circuit board. Here, "direct connection" means a state in which the electrodes of the semiconductor element and the electrodes of the circuit board are electrically connected without direct contact via wires or wiring. Furthermore, in the semiconductor device of the second aspect of this embodiment, at least one of the electrodes provided on the semiconductor element and the electrodes provided on the circuit board is a bump, while the other electrode can be either a bump or a pad.

[0064] The semiconductor device of the second aspect of this embodiment is also manufactured by at least a bonding process and a heating and pressurizing process. In this case, each process can be implemented by the two embodiments described below (the first embodiment or the second embodiment).

[0065] First Implementation Method In the first embodiment, the bonding process and the heating and pressurizing process are performed in the order described below.

[0066] Bonding process: The bonding process is a process of bonding the adhesive film of this embodiment to the electrode mounting surface of the electrode on which the semiconductor element is mounted. Similar to the case of manufacturing the semiconductor device of the first aspect of this embodiment, the adhesive film can be bonded to the electrode mounting surface of the semiconductor element using a laminator or the like.

[0067] Heating and pressurizing process: The heating and pressurizing process is a process of heating and pressurizing a laminate in which semiconductor elements, adhesive films, and circuit boards are sequentially stacked. Here, the laminate is formed by bringing the side of the adhesive film opposite to the side where the semiconductor elements are disposed into contact (bonding) with the electrode surface of the circuit board electrodes, such that the electrodes of the semiconductor elements face each other. Furthermore, the heating and pressurizing process can be performed in the same manner as in the manufacture of the semiconductor device according to the first aspect of this embodiment.

[0068] Second Implementation Method In the second embodiment, the bonding process and the heating and pressurizing process are performed in the order described below.

[0069] Bonding process: The bonding process is a process of bonding the adhesive film of this embodiment to the electrode mounting surface of the circuit board on which the electrodes are mounted. Similar to the case of manufacturing the semiconductor device of the first aspect of this embodiment, the adhesive film can be bonded to the electrode mounting surface of the circuit board using a laminator or the like.

[0070] Heating and pressurizing process: The heating and pressurizing process is a process of heating and pressurizing a laminate in which semiconductor elements, adhesive films, and circuit boards are sequentially stacked. Here, the laminate is formed by making the side of the adhesive film opposite to the side where the circuit board is disposed contact (adhere) with the electrode surface of the semiconductor element's electrode disposed, with the electrodes of the circuit board facing each other. Furthermore, the heating and pressurizing process can be performed in the same manner as in the case of manufacturing the semiconductor device of the first aspect of this embodiment.

[0071] In addition, in the first and second embodiments, after the heating and pressurizing process is completed, various subsequent processes (e.g., cutting, back grinding, formation of rewire layers, etc.) can be carried out as needed.

[0072] The application of the semiconductor device in the first aspect and the second aspect of this embodiment is not particularly limited. For example, various semiconductor sensors such as semiconductor memory, logic semiconductor, and image sensor can be cited. Example

[0073] The following examples illustrate specific examples of the present invention, but the present invention is not limited to the examples described below.

[0074] 1. Preparation of coating solution for adhesive film fabrication The adhesive film coating solutions of each embodiment and comparative example were prepared by mixing and dissolving the following listed components, which are raw materials for the coating solution used in the adhesive film preparation, in a manner that forms the composition shown in Table 1.

[0075] (A) Thermosetting resin A1: Styrene-modified polyphenylene ether resin (manufactured by Mitsubishi Gas Chemical, OPE-2st-1200) A2: Styrene-modified polyphenylene ether resin (manufactured by Mitsubishi Gas Chemical, OPE-2st-2200) A3: Aminophenol type epoxy resin (manufactured by Mitsubishi Chemical (Mitsubishi Kemica), jER630)

[0076] (B) Thermoplastic resin B1: Styrene-based thermoplastic elastomer (manufactured by Asahi Kasei, H1221) B2: Styrene-based thermoplastic elastomer (manufactured by ENEOS Materials, TR2003) B3: Phenoxy resin (manufactured by Mitsubishi Chemical, YX8100BH30. Solid content: 30% by mass; solvent (cyclohexanone and MEK): 70% by mass) B4: Styrene-based thermoplastic elastomer (manufactured by Kurare, 8004)

[0077] (C) Other ingredients Curing catalyst: Acrylate-imidazolium adduct curing agent (manufactured by ADEKA, EH2021)

[0078] Solvent: ·Methylcyclohexane Cyclohexanone MEK (methyl ethyl ketone)

[0079] [Table 1]

[0080] 2. Fabrication of multilayer films including adhesive films Using a doctor blade coater, an adhesive film forming coating liquid having the compositions shown in Table 1 for each embodiment and comparative example is applied to one side of a PET film (substrate film) that has undergone release treatment on both sides, thereby forming a coated film. Next, the coated film formed on the PET film is placed in an oven and dried at 110°C for 10 minutes, thereby forming an adhesive film having the compositions and thicknesses shown in Table 2. Furthermore, after forming the adhesive film, a PET film that has undergone release treatment on both sides is laminated onto the surface of the adhesive film as a protective film, thereby producing a multilayer film in which a PET film (substrate film), an adhesive film, and a PET film (protective film) are sequentially stacked.

[0081] Furthermore, when using the coating solution of Comparative Example 2, an adhesive film could not be formed. The composition of the solid components in the coating solution of Comparative Example 2, after solvent removal, consisted of 80% thermosetting resin A1 and 20% thermoplastic resin B1 by mass. Moreover, the thermosetting resin A1, which constituted the majority of the solid components, was a hard solid at 25°C. Therefore, when forming a film on a substrate film using the coating solution, only a hard and brittle film could be formed, and a continuous film (thin film) with uniform thickness in the horizontal direction and free from defects such as cracks, fissures, and defects could not be formed.

[0082] 3. Evaluation Results Table 2 shows the connection resistance values ​​evaluated using the adhesive films of each embodiment and comparative example. It also shows the composition, thickness, width of the temperature range exhibiting a melt viscosity below 50,000 Pa·s in the temperature range greater than 90°C and less than 200°C, minimum melt viscosity V1 in the temperature range greater than 90°C and less than 200°C, melt viscosity V2 at 200°C, and melt viscosity ratio (V2 / V1). Furthermore, Table 2 also shows the melt viscosity at 120°C for reference.

[0083] [Table 2]

[0084] 4. Measurement and Evaluation Methods The following are the methods for determining the thickness of the adhesive film, the width of the temperature range exhibiting a melt viscosity below 50,000 Pa·s in the temperature range greater than 90°C and less than 200°C, the minimum melt viscosity V1, the melt viscosity V2, the melt viscosity at 120°C, and the connection resistance value, as shown in Table 2.

[0085] 4.1 Thickness of the adhesive film The thickness Tt of the multilayer film, the thickness T1 of the substrate film used to fabricate the multilayer film, and the thickness T2 of the protective film used to fabricate the multilayer film were measured using a contact thickness gauge. Then, the thickness of the adhesive film was calculated by subtracting the thicknesses T1 and T2 from the thickness Tt.

[0086] 4.2 The minimum melt viscosity V1, melt viscosity V2, melt viscosity at 120℃, and the width of the temperature range exhibiting a melt viscosity below 50,000 Pa·s in the temperature range greater than 90℃ and less than 200℃ of the adhesive film. The melt viscosity was determined in the following sequence. First, a test sample was prepared by folding the adhesive film obtained from peeling the substrate film and protective film from the multilayer film to a thickness of 240 μm. Next, the test sample was sandwiched between a pair of parallel plates (diameter: 5 mm), and the melt viscosity was measured using an ARES-G2 rheometer (manufactured by TA Instruments). The measurement conditions were set as follows: load: 100 g, measurement temperature range: 30 °C to 200 °C, heating rate: 20 °C / min, frequency: 1 Hz. Then, based on the measurement results, the minimum melt viscosity V1 (Pa·s) in the temperature range greater than 90 °C and less than 200 °C, the melt viscosity V2 (Pa·s) at 200 °C, and the melt viscosity at 120 °C were calculated. Furthermore, based on the melt viscosity versus temperature curves obtained when measuring the lowest melt viscosity V1, melt viscosity V2, and melt viscosity at 120°C, the width of the temperature region exhibiting melt viscosity below 50,000 Pa·s in the temperature range greater than 90°C and less than 200°C was determined. Additionally, in cases where the melt viscosity is too high to be measured, the melt viscosity value is marked as ∞ in Table 2.

[0087] 4.3 Connection Resistance Value (1) Preparation of the sample for determination The connection resistance value was measured in the following order. First, semiconductor elements X1, Y1, X2, and Y2 with the specifications shown below were prepared as wafer-shaped semiconductor elements. <Semiconductor Component X1> • Electrode type • Material: Au bump (cross-sectional shape: square, bump height: 0.5μm) • Electrode planar shape and size: circular (0.5μm in diameter) • Electrode spacing: 1μm <Semiconductor Component Y1> • Electrode type • Material: Sn bump (cross-sectional shape: arc, bump height: 0.5μm) • Electrode planar shape and size: circular (0.5μm in diameter) • Electrode spacing: 1μm <Semiconductor Component X2> • Electrode type • Material: Au bump (cross-sectional shape: rectangular, bump height: 0.5μm) • Electrode planar shape • Dimensions: Circular (diameter 2.0μm) • Electrode spacing: 4μm <Semiconductor Component Y2> • Electrode type • Material: Sn bump (cross-sectional shape: arc, bump height: 0.5μm) • Electrode planar shape • Dimensions: Circular (diameter 2.0μm) • Electrode spacing: 4μm

[0088] Next, after peeling off the protective film from the multilayer film, the side of the multilayer film with the adhesive film is attached to the electrode mounting surface of the semiconductor element X1. Then, the substrate film is peeled off from the adhesive film attached to the electrode mounting surface of the semiconductor element X1. Next, with the center point of the Au bump on the semiconductor element X1 side aligned with the center point of the Sn bump on the semiconductor element Y1 side, the side with the adhesive film attached to the semiconductor element X1 is bonded to the electrode mounting surface of the semiconductor element Y1 to form a laminate. The laminate is then heated and pressurized using a flip-chip bonding device. The heating and pressurizing conditions are set as follows: temperature: 250°C, pressure: 300 kg / cm². 2 Thus, a sample for measurement was obtained, consisting of a semiconductor element X1, a cured layer composed of a cured adhesive film, and a semiconductor element Y1 stacked sequentially (electrode spacing = 1 μm).

[0089] In addition, by replacing semiconductor elements X1 and Y1 with semiconductor elements X2 and Y2, and in the same order as when preparing the sample for measurement (electrode spacing = 1 μm), a sample for measurement (electrode spacing = 4 μm) was obtained by sequentially stacking semiconductor element X2, a cured layer consisting of a cured adhesive film, and semiconductor element Y2.

[0090] In addition, except for Comparative Example 2, which could not form a film, the adhesive films of each embodiment and comparative example were heated at the same temperature as the heating and pressurization conditions using the flip chip bonding device. The degree of curing of the resulting cured products was checked by visual observation, etc., and it was confirmed that all cured products were fully cured.

[0091] (2) Measurement of connection resistance value Next, the connection resistance value (i.e., the connection resistance value of the connection between the Au bump and the Sn bump) of the test sample was measured using a four-terminal measurement method. A multimeter (MLR21, manufactured by ETAC) was used to measure 13 locations on one test sample, and the average value of the connection resistance measured at each location is shown in Table 2. Furthermore, from the viewpoint of electrical connection reliability, a connection resistance value of 60Ω or less is suitable, and the lower the value, the better. In cases where the connection resistance value is too high to measure, the connection resistance value is marked as ∞ in Table 2.

Claims

1. An adhesive film, wherein, The adhesive film is used for bonding semiconductor components to each other, or for bonding semiconductor components to a circuit board. The width of the temperature region exhibiting a melt viscosity below 50,000 Pa·s within the temperature range of greater than 90℃ and less than 200℃ is greater than 40℃ and less than 110℃. The ratio of the melt viscosity V2 at 200°C to the lowest melt viscosity V1 in the temperature range greater than 90°C and less than 200°C, i.e., V2 / V1, is greater than 1.

0.

2. The adhesive film according to claim 1, wherein, The melt viscosity V2 is above 8000 Pa·s.

3. The adhesive film according to claim 1 or 2, wherein, The thickness ranges from 0.5μm to 6μm.

4. The adhesive film according to any one of claims 1 to 3, wherein, The thickness ranges from 0.5μm to 2.5μm.

5. The adhesive film according to any one of claims 1 to 4, wherein, The circuit board is a substrate on which a circuit is formed on a silicon substrate or a substrate on which a circuit is formed on a glass substrate.

6. The adhesive film according to any one of claims 1 to 5, wherein, The material constituting the surface of the electrode disposed on the semiconductor element is a metallic material containing at least one element selected from the group consisting of Au and Sn as a main component.

7. The adhesive film according to any one of claims 1 to 6, wherein, The maximum diameter of the electrodes disposed on the semiconductor element is 0.5 μm to 5 μm.

8. The adhesive film according to any one of claims 1 to 7, wherein, The electrode spacing between the electrodes disposed on the semiconductor element is 0.5 μm to 5 μm.

9. The adhesive film according to any one of claims 1 to 8, wherein, The material constituting the surface of the electrodes disposed on the circuit board is a metallic material containing at least one element selected from the group consisting of Au and Sn as a main component.

10. The adhesive film according to any one of claims 1 to 9, wherein, The maximum diameter of the electrodes disposed on the circuit board is 0.5μm to 5μm.

11. The adhesive film according to any one of claims 1 to 10, wherein, The electrode spacing between the electrodes disposed on the circuit board is 0.5μm~5μm.

12. The adhesive film according to any one of claims 1 to 11, wherein, The adhesive film comprises a thermosetting resin and a thermoplastic resin.

13. The adhesive film according to any one of claims 12, wherein, The thermosetting resin contains polyphenylene ether resin as its main component.

14. The adhesive film according to claim 12 or 13, wherein, The thermoplastic resin contains a styrene-based elastomer as its main component.

15. The adhesive film according to any one of claims 1 to 14, wherein, The adhesive film does not contain fillers.

16. A semiconductor device, wherein, The semiconductor device includes: The first semiconductor device has electrodes. A second semiconductor element having electrodes that are directly connected to the electrodes of the first semiconductor element, and The cured product of the adhesive film according to any one of claims 1 to 15 disposed between the first semiconductor element and the second semiconductor element.

17. A method for manufacturing a semiconductor device, wherein, The manufacturing method includes: The process of attaching the adhesive film according to any one of claims 1 to 15 to the electrode mounting surface of the electrode on which the first semiconductor element is disposed, and The process involves heating and pressurizing a laminate of sequentially stacked semiconductor elements by bringing the opposite side of the adhesive film where the first semiconductor element is disposed to the electrode surface where the second semiconductor element is disposed, with the electrodes of the first semiconductor element and the second semiconductor element facing each other.

18. A semiconductor device, wherein, The semiconductor device includes: Semiconductor devices, which have electrodes, A circuit board having electrodes that are directly connected to the electrodes of the semiconductor element, and Cured form of the adhesive film according to any one of claims 1 to 15 disposed between the semiconductor element and the circuit substrate.

19. A method for manufacturing a semiconductor device, wherein, The manufacturing method includes: The process of attaching the adhesive film according to any one of claims 1 to 15 to the electrode mounting surface of an electrode on which a semiconductor element is disposed, and The process involves heating and pressurizing a laminate in which the semiconductor element, the adhesive film, and the circuit substrate are sequentially stacked, by bringing the side of the adhesive film opposite to the side where the semiconductor element is disposed to the electrode surface where the electrode of the circuit substrate is disposed, with the electrodes of the semiconductor element facing each other.

20. A method for manufacturing a semiconductor device, wherein, The manufacturing method includes: The process of attaching the adhesive film according to any one of claims 1 to 15 to the electrode mounting surface on which the electrodes of the circuit board are mounted, and The process involves heating and pressurizing a laminate in which the semiconductor element, the adhesive film, and the circuit substrate are sequentially stacked, by bringing the side of the adhesive film opposite to the side on which the circuit substrate is disposed to contact the electrode surface on which the semiconductor element is disposed.

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