Encapsulation resin composition, laminated sheet, cured product, semiconductor device, and method for producing semiconductor device

Abstract

Provided is a resin composition for encapsulation: even if the resin composition for encapsulation is heated and subjected to ultrasonic vibration to hermetically seal the gap between the substrate member and the semiconductor chip bonded to the substrate member, the resin composition for encapsulation can reduce the number of residual pores left in the gap between the substrate member and the semiconductor chip bonded to the substrate member. The resin composition for encapsulation is used to hermetically seal the gap between the substrate member 2 and the semiconductor chip 3 bonded to the substrate member 2. The reaction start temperature of the resin composition for encapsulation is 160°C or less. The melt viscosity of the resin composition for encapsulation is 200Pa·s or less at the reaction start temperature, 400Pa·s or less at any temperature equal to or higher than the reaction start temperature 40°C lower and equal to or lower than the reaction start temperature, and 1,000Pa·s or less at a temperature 50°C lower than the reaction start temperature.

Description

Technical Field

[0001] The present invention generally relates to an encapsulation resin composition, a laminated sheet, a cured product, a semiconductor device, and a method for making a semiconductor device. More specifically, the present invention relates to an encapsulation resin composition suitable for airtightly sealing a gap between a base member and a semiconductor chip, a laminated sheet, a cured product of the encapsulation resin composition, a semiconductor device including an encapsulation member made of the cured product, and a method for making a semiconductor device including the encapsulation member. Background Art

[0002] As a bottom filling technology using a pre-application process, not only a technology using a resin composition that is in a liquid phase at room temperature (which is called a "non-conductive paste process" and also called an "NCP process"), but also a technology using a sheet of a resin composition (which is called a "non-conductive film process" and also called an "NCF process") is known (see, for example, Patent Document 1).

[0003] When a semiconductor device is made by bonding a semiconductor chip to a substrate as disclosed in Patent Document 1, a sheet of a resin composition can be stacked on the semiconductor chip, and then the semiconductor chip is picked up by a bonding head and mounted on the substrate in such a state. Heating the bonding head in this state also heats the resin composition and the raised electrode. This melts the solder of the raised electrode, thereby connecting the raised electrode to the conductor line of the substrate and also solidifying the resin composition to form an encapsulation member.

[0004] Reference List

[0005] Patent Literature

[0006] Patent Document 1: JP 2011-140617 A SUMMARY OF THE INVENTION

[0008] An object of the present invention is to provide an encapsulation resin composition that can reduce the number of residual voids remaining in an encapsulation member even if an encapsulation member is formed by heating the encapsulation resin composition placed in a gap between a base member and a semiconductor chip and ultrasonically vibrating the encapsulation resin composition.

[0009] Another object of the present invention is to provide a laminated sheet made of the encapsulation resin composition, a cured product of the encapsulation resin composition, a semiconductor device including an encapsulation member made of the cured product, and a method for producing such a semiconductor device.

[0010] The encapsulation resin composition according to one aspect of the present invention is used to hermetically seal a gap between a base member and a semiconductor chip bonded to the base member. The reaction starting temperature of the encapsulation resin composition is 160°C or lower. The encapsulation resin composition has a melt viscosity of 200 Pa･s or lower at the reaction starting temperature, a melt viscosity of 400 Pa･s or lower at a temperature 40°C lower than the reaction starting temperature and any temperature equal to or lower than the reaction starting temperature, and a melt viscosity of 1,000 Pa･s or lower at a temperature 50°C lower than the reaction starting temperature.

[0011] A laminated sheet according to another aspect of the present invention includes: an encapsulating resin composition having a sheet shape; and a supporting sheet for supporting the encapsulating resin composition thereon.

[0012] A cured product according to still another aspect of the present invention is obtained by thermally curing the above encapsulating resin composition.

[0013] A semiconductor device according to another aspect of the present invention includes: a base member; a semiconductor chip bonded face-down to the base member; and an encapsulation member hermetically sealing a gap between the base member and the semiconductor chip. The encapsulation member is made of the above-mentioned cured product.

[0014] According to another aspect of the present invention, a method for manufacturing a semiconductor device includes: arranging a semiconductor chip having a protruding electrode on a surface of a base member having a conductor line, so that the above-mentioned encapsulation resin composition is interposed between the semiconductor chip and the base member so that the conductor line faces the protruding electrode; and applying ultrasonic vibration to the encapsulation resin composition while heating the encapsulation resin composition to cure the encapsulation resin composition and electrically connect the conductor line to the protruding electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1A is a schematic cross-sectional view showing a semiconductor device according to an exemplary embodiment of the present invention;

[0017] Figure 1B is a schematic cross-sectional view showing a semiconductor device according to another exemplary embodiment of the present invention;

[0018] Figure 2 is a schematic cross-sectional view showing a laminated sheet according to an exemplary embodiment of the present invention; and

[0019] Figure 3A -3D is a schematic cross-sectional view showing various process steps of bonding a semiconductor chip to a base member according to an exemplary embodiment of the present invention.

[0020] Implementation Description

[0021] First, it will be described exactly how the inventors accomplished the present invention.

[0022] In order to bond a flip-chip type semiconductor chip face-down to a base member, a so-called "bottom filling technique" is generally used as a well-known technique, which is to seal the gap between the base member and the semiconductor chip by filling the gap with a resin composition after the semiconductor chip is mounted on the base member.

[0023] When making a semiconductor device, the spacing of its raised electrodes needs to be even narrower to meet the growing demand for reducing the overall size, weight and thickness of the semiconductor device. Therefore, a pre-application process is adopted as a bottom filling technology. According to the pre-application process, for example, a base member with a conductor circuit, a semiconductor chip with a raised electrode and a resin composition in a liquid phase at room temperature can be provided. The resin composition is placed in a suitable position on the base member, the semiconductor chip is mounted at a position where the resin composition is placed on the base member, and the raised electrode is arranged on the conductor circuit. In this state, the resin composition and the raised electrode are heated to solidify the resin composition, thereby forming an encapsulation member and the raised electrode is electrically connected to the conductor circuit.

[0024] As a bottom filling technology using such a pre-application process, not only a technology using a resin composition in a liquid phase at room temperature (which is called a "non-conductive paste process" and also called an "NCP process"), but also a technology using a sheet of a resin composition (which is called a "non-conductive film process" and also called an "NCF process") is known (see, for example, JP 2011-140617 A).

[0025] When a semiconductor device is made by bonding a semiconductor chip to a substrate as disclosed in JP 2011-140617 A, a sheet of a resin composition can be stacked on the semiconductor chip, and then the semiconductor chip is picked up by a bonding head and mounted on the substrate in such a state. Heating the bonding head in this state also heats the resin composition and the raised electrode. This melts the solder of the raised electrode, thereby connecting the raised electrode to the conductor line of the substrate and also solidifying the resin composition to form an encapsulation member.

[0026] According to the method disclosed in JP 2011-140617 A, in order to melt the solder of the bump electrode, the resin composition and the bump electrode are heated to a relatively high temperature of about 180°C to about 260°C. Therefore, in order to repeatedly bond the semiconductor chip to the substrate, the bonding head needs to be cooled each time the semiconductor chip is bonded to prevent the resin composition from solidifying before being connected to the bump electrode and the conductor line. This is why the bonding head needs to repeatedly increase and decrease its temperature, thereby causing a decrease in the productivity of the semiconductor device.

[0027] However, bonding the protruding electrode to the conductor line by applying ultrasonic vibration to the protruding electrode eliminates the need to melt the solder of the protruding electrode at a high temperature, thereby enabling the use of a lower heating temperature. This eliminates the need to cool the joint head. However, in this case, the applied ultrasonic vibration will produce pores in the resin composition, or will make the produced pores small enough to increase the possibility of leaving micropores in the encapsulation member made of the encapsulation resin composition in the gap between the protruding electrode and the conductor line. The presence of such residual pores in the encapsulation member leads to a decrease in the performance of the semiconductor device.

[0028] Therefore, the inventors obtained the basic concept of the present invention to overcome such problems by providing an encapsulation resin composition that can reduce the number of residual pores remaining in the encapsulation member even if the encapsulation member is formed by heating the encapsulation resin composition placed in the gap between the base member and the semiconductor chip and ultrasonically vibrating the encapsulation resin composition.

[0029] Next, an exemplary embodiment of the present invention will be described. As used herein, "(meth)acrylic acid-" is a general term for "acrylic acid-" and "methacrylic acid-". For example, (meth)acryloyl is a general term for acryloyl and methacryloyl. In addition, the solid content of the encapsulating resin composition herein refers to the content of the encapsulating resin composition from which volatile components such as solvents are removed.

[0030] The encapsulation resin composition according to this embodiment is used to hermetically seal the gap between the base member 2 and the semiconductor chip 3 bonded to the base member 2. The reaction starting temperature of the encapsulation resin composition is 160°C or lower. The melt viscosity of the encapsulation resin composition is 200 Pa･s or lower at the reaction starting temperature of the encapsulation resin composition, 400 Pa･s or lower at any temperature that is 40°C lower than the reaction starting temperature and is equal to or lower than the reaction starting temperature, and 1,000 Pa･s or lower at a temperature that is 50°C lower than the reaction starting temperature.

[0031] Even if the encapsulation member 41 is formed by heating the encapsulation resin composition placed in the gap between the base member 2 and the semiconductor chip 3 and ultrasonically vibrating the encapsulation resin composition, this embodiment reduces the amount of residual voids remaining in the encapsulation member 41 (see Figure 3A –3C).

[0032] In addition, this embodiment also provides a laminated sheet 6 made of the encapsulating resin composition (see Figure 2 ), a cured product of the encapsulation resin composition and a semiconductor device 1 including an encapsulation member 41 made of the cured product (see Figure 1A and 1B ).

[0033] In this embodiment, the melt viscosity and the reaction start temperature are obtained from a melt viscosity curve, which shows the relationship between temperature and melt viscosity in the case where the melt viscosity is measured when the temperature of the resin composition is increased. Specifically, the temperature at which the melt viscosity begins to increase in the melt viscosity curve is the reaction start temperature. As the temperature increases, the encapsulating resin composition, for example, melts and has a reduced viscosity within a certain temperature range. The components in the encapsulating resin composition are reacted at a temperature at which the melt viscosity begins to increase, which also causes the melt viscosity to begin to increase. The reaction start temperature varies according to the chemical composition of the encapsulating resin composition and can be controlled by appropriately adjusting the components in the encapsulating resin composition. In this embodiment, the reaction start temperature refers herein to a temperature higher than the temperature corresponding to the minimum melt viscosity in the melt viscosity curve of the encapsulating resin composition, and is a temperature at a viscosity of 50 Pa.s higher than the minimum melt viscosity.

[0034] Specifically, the melt viscosity and the reaction starting temperature can be obtained by the following method.

[0035] First, the temperature dependence of the melt viscosity of the encapsulating resin composition is measured using a rheometer under conditions including a temperature range of 100°C to 300°C, a heating rate of 60°C / min, and an angular velocity of 0.209rad / s. In this way, a melt viscosity curve is obtained. As a rheometer used in this measurement, for example, a rheometer model AR2000ex manufactured by TA Instruments, Inc. can be used. The minimum melt viscosity and the temperature corresponding to the melt viscosity that has been increased by 50 Pa･s from the minimum melt viscosity are detected by the melt viscosity curve thus obtained, so that the reaction start temperature of the encapsulating resin composition can be obtained.

[0036] When the encapsulation member 41 is made of the encapsulation resin composition, the encapsulation resin composition placed in the gap between the base member 2 and the semiconductor chip 3 is heated and ultrasonically vibrated. When heated, the encapsulation resin composition melts and flows. In addition, when ultrasonically vibrated, the encapsulation resin composition joins the conductor line 21 on the base member 2 to the protruding electrode 31 of the semiconductor chip 3. When further heated, the encapsulation resin composition is cured to form the encapsulation member 41.

[0037] As described above, the melt viscosity of the encapsulating resin composition according to this embodiment at the reaction start temperature is 200 Pa·s or less. Therefore, setting the temperature at which the encapsulating resin composition is heated to a temperature near the reaction start temperature when making the encapsulating member 41 makes it possible to reduce the melt viscosity when the encapsulating resin composition is melted. This makes it possible to easily remove residual pores (if any) from the encapsulating resin composition.

[0038] In addition, the encapsulating resin composition has a relatively low melt viscosity of 1,000 Pa･s or less even at a temperature 50°C lower than the reaction start temperature. Therefore, even when the temperature becomes uneven in the molten encapsulating resin composition, this reduces the possibility of generating a high viscosity portion in the encapsulating resin composition. As a result, this reduces the possibility that the high viscosity portion hinders the removal of the voids.

[0039] In addition, setting the heating temperature to a temperature near the reaction start temperature enables the curing reaction of the encapsulating resin composition to proceed quickly after the encapsulating resin composition has melted, thereby causing the viscosity of the encapsulating resin composition to increase sharply. This reduces the possibility of new pores being generated by ultrasonic vibration due to the presence of low molecular components in the encapsulating resin composition. As a result, this reduces the possibility of pores remaining in the encapsulating member 41 made of the encapsulating resin composition.

[0040] In addition, the melt viscosity of the encapsulating resin composition is 400 Pa·s or less at any temperature that is equal to or higher than the reaction starting temperature and equal to or lower than the reaction starting temperature. This allows the encapsulating resin composition to have a low viscosity in a wide temperature range around the reaction starting temperature. This is advantageous in setting the heating temperature when making the encapsulating member 41.

[0041] Note that the reaction start temperature of the encapsulating resin composition is a measured value obtained by measuring the melt viscosity under the above-mentioned specific conditions. Therefore, the reaction start temperature of the encapsulating resin composition is different from the temperature when the reaction of the encapsulating resin composition actually starts. The curing reaction of the encapsulating resin composition can even be carried out at a temperature lower than the reaction start temperature. Therefore, when making the encapsulating member 41, the heating temperature is set near the reaction start temperature so that even if the heating temperature is lower than the reaction start temperature, the curing reaction of the encapsulating resin composition can also be carried out.

[0042] As can be seen from the previous description, even if the encapsulation member 41 is formed by heating the encapsulation resin composition placed in the gap between the base member 2 and the semiconductor chip 3 at a relatively low temperature and ultrasonically vibrating the encapsulation resin composition, the encapsulation resin composition according to this embodiment reduces the number of residual pores remaining in the encapsulation member 41. Therefore, in the case where the semiconductor chip 3 is a flip chip bonded to the base member 2, even if the encapsulation resin composition is heated and the protruding electrodes 31 of the semiconductor chip 3 are bonded to the conductor lines 21 on the base member 2 by ultrasonic vibration, this reduces the number of residual pores remaining in the encapsulation member 41.

[0043] The reaction start temperature is suitably in the range of 100°C to 160°C. In this case, even when the temperature of heating the encapsulation resin composition is low when making the encapsulation member 41, the number of pores remaining in the encapsulation member 41 can be reduced as described above. In addition, when the semiconductor chip is joined, ultrasonic vibration is applied while heating the encapsulation resin composition so that even if the heating temperature is reduced compared to the situation where ultrasonic vibration is not applied, electrical connection can be established between the base member and the semiconductor chip. Even if the heating temperature is reduced when ultrasonic vibration is also applied, the reaction start temperature is set to a temperature within the range of 100°C to 160°C, which also reduces the number of pores remaining in the encapsulation member 41. The heating temperature is suitably equal to or higher than a temperature 30°C lower than the reaction start temperature. This will significantly achieve the advantages of this embodiment. The heating temperature is more suitably equal to or higher than a temperature 30°C lower than the reaction start temperature and equal to or lower than a temperature 10°C higher than the reaction start temperature, and even more suitably within the range of 100°C to 150°C.

[0044] Such melt viscosity behavior in the encapsulating resin composition is achieved by appropriately selecting components in the encapsulating resin composition and appropriately adjusting the contents of those components in the encapsulating resin composition. Next, an exemplary chemical composition of the encapsulating resin composition for achieving such melt viscosity behavior will be described.

[0045] The encapsulation resin composition suitably contains an acrylic compound as component (A) (hereinafter referred to as "acrylic compound (A)"), a polyphenylene ether resin containing a substituent (b1) having a free radical polymerization property as component (B) (hereinafter referred to as "polyphenylene ether resin (B)"), and a thermal free radical polymerization initiator as component (C) (hereinafter referred to as "thermal free radical polymerization initiator (C)"). The encapsulation resin composition containing these components further reduces the number of residual pores remaining in the cured product of the encapsulation resin composition. In addition, this also reduces the possibility of the encapsulation member 41 made of the cured product of the encapsulation resin composition being peeled off from the base member 2. Therefore, sealing the gap between the base member 2 and the semiconductor chip 3 with the cured product of the encapsulation resin composition will improve the reliability of the semiconductor device 1. In addition, the encapsulation resin composition containing the polyphenylene ether resin (B) and the like is conducive to adjusting the melt viscosity of the encapsulation resin composition, so that the encapsulation resin composition can have a low melt viscosity. In addition, the polyphenylene ether resin (B) contains a substituent (b1) having a free radical polymerization property. Therefore, when the encapsulation resin composition is thermally cured, the polymerization of the polyphenylene ether resin (B) and the acrylic compound (A) forms a macromolecule. In other words, the polyphenylene ether resin (B) is incorporated into the skeleton of the macromolecule. This enables the cured product of the encapsulation resin composition to have excellent heat resistance and moisture resistance.

[0046] In this embodiment, the acrylic compound (A) herein refers to a compound having a (meth)acryloyl group. That is, the acrylic compound (A) is a compound having at least one of an acryloyl group or a methacryloyl group. The acrylic compound (A) may contain at least one of a monomer or an oligomer.

[0047] The encapsulating resin composition containing the acrylic compound (A) reduces the possibility of voids being generated in the encapsulating member 41 made of the encapsulating resin composition. This is because the encapsulating resin composition increases its viscosity during the initial stage in which the acrylic compound (A) is cured by a radical polymerization reaction, thereby reducing the possibility of voids being generated inside.

[0048] In order to ensure sufficient heat resistance of the encapsulating member 41, the acrylic compound (A) suitably includes a compound having two or more (meth)acryloyl groups per molecule, more suitably includes a compound having two to six (meth)acryloyl groups per molecule, and even more suitably includes a compound having two (meth)acryloyl groups per molecule.

[0049] Examples of the compound having two (meth)acryloyl groups per molecule include ethylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, dimer glycol di(meth)acrylate, dimethylol tricyclodecane di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, (meth)acrylate, polyethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, glycerol di(meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol di(meth)acrylate, zinc di(meth)acrylate, cyclohexanediol di(meth)acrylate, cyclohexanedimethanol di(meth)acrylate, cyclohexanediethanol di(meth)acrylate, cyclohexanedialkyl alcohol di(meth)acrylate and dimethanol tricyclodecane di(meth)acrylate.

[0050] Examples of the compound having two (meth)acryloyl groups per molecule include a reactant of 1 mole of bisphenol A, bisphenol F or bisphenol AD ​​and 2 moles of glycidyl acrylate; and a reactant of 1 mole of bisphenol A, bisphenol F or bisphenol AD ​​and 2 moles of glycidyl methacrylate.

[0051] Examples of compounds having two or more (meth)acryloyl groups per molecule include (meth)acrylates having a cross-linked polycyclic structure. Specifically, examples of compounds having two or more (meth)acryloyl groups per molecule include compounds represented by the following formula (I) and compounds represented by the following formula (II). When the encapsulation resin composition contains at least one of the compounds represented by the following formula (I) or the compounds represented by the following formula (II), the heat resistance of the encapsulation member 41 is significantly improved.

[0052] [Chemical formula 1]

[0053]

[0054] In formula (I), R 1 and R 2 are independently a hydrogen atom or a methyl group, a is 1 or 2, and b is 0 or 1.

[0055] [Chemical formula 2]

[0056]

[0057] In formula (II), R 3 and R 4are independently a hydrogen atom or a methyl group, X is a hydrogen atom, a methyl group, a hydroxymethyl group, an amino group or a (meth)acryloyloxymethyl group, and c is 0 or 1.

[0058] More specific examples of the (meth)acrylate having a cross-linked polycyclic structure include: a (meth)acrylate having a dicyclopentadiene skeleton, wherein in formula (I), a is 1 and b is 0; a (meth)acrylate having a perhydro-1,4:5,8-dimethylnaphthalene skeleton, wherein in formula (II), c is 1; a (meth)acrylate having a norbornene skeleton, wherein in formula (II), c is 0; dicyclopentadienyl diacrylate (tricyclodecane dimethanol diacrylate), wherein in formula (I), R 1 and R 2 is a hydrogen atom, a = 1, and b = 0; perhydro-1,4:5,8-dimethylnaphthalene-2,3,7-trihydroxymethyl triacrylate, wherein in formula (II), X is an acryloyloxymethyl group, R 3 and R 4 is a hydrogen atom, and c is 1; norbornene dihydroxymethyl diacrylate, wherein in formula (II), X, R 3 and R 4 is a hydrogen atom, and c is 0; and perhydro-1,4:5,8-dimethylnaphthalene-2,3-dihydroxymethyl diacrylate, wherein in formula (II), X, R 3 and R 4 is a hydrogen atom, and c is 1. In particular, the (meth)acrylate having a cross-linked polycyclic structure suitably includes at least one of dicyclopentadienyl diacrylate or norbornene dimethylol diacrylate.

[0059] Examples of compounds having two or more (meth) acryloyl groups include di(meth) acrylates having a structure in which alkylene oxide is added to a bisphenol skeleton. More specific examples of compounds having two or more (meth) acryloyl groups include compounds represented by the following formula (III) and compounds represented by the following formula (IV). When the acrylic compound (A) contains at least one of the compounds represented by the formula (III) or the compounds represented by the formula (IV), the adhesion between the encapsulation member 41 and the semiconductor chip 3 and the base member 2 increases.

[0060] [Chemical formula 3]

[0061]

[0062] In formula (III), R 5 represents hydrogen, methyl or ethyl, R 6 represents a divalent organic group, and m and n each represent an integer within the range of 1 to 20.

[0063] [Chemical formula 4]

[0064]

[0065] In formula (IV), R 5 represents hydrogen, methyl or ethyl, R 6 represents a divalent organic group, and m and n each represent an integer within the range of 1 to 20.

[0066] More specific examples of the di(meth)acrylate having a structure in which an alkylene oxide is added to a bisphenol skeleton include: EO-modified bisphenol A type di(meth)acrylate (wherein n=2 to 20), such as Aronix M-210, M-211B (produced by Toagosei Co., Ltd.), NK esters ABE-300, A-BPE-4, A-BPE-6, A-BPE-10, A-BPE-20, A-BPE-30, BPE-100, BPE-200, BPE-500, BPE-900 and BPE-1300N (produced by Shin-Nakamura Chemical Co., Ltd.); Aronix M-208 (produced by Toagosei Co., Ltd.) and other EO-modified bisphenol F type di(meth)acrylate (wherein n=2 to 20); PO-modified bisphenol A type di(meth)acrylate (wherein n=2 to 20); 2 to 20), such as Denacol Acrylate DA-250 (produced by Nagase ChemteX Corporation) and Viscoat 540 (produced by Osaka Organic Chemical Industry Ltd.); and PO-modified phthalic acid diacrylates, such as Denacol acrylate DA-721 (produced by Nagase ChemteX Corporation).

[0067] The compound having two or more (meth)acryloyl groups preferably contains epoxy (meth)acrylate. That is, the acrylic compound (A) preferably contains epoxy (meth)acrylate. In this case, especially when the encapsulating resin composition contains epoxy resin, not only the reactivity of the encapsulating resin composition is improved, but also the heat resistance and adhesion of the encapsulating member 41 are improved.

[0068] The epoxy (meth)acrylate may be an oligomer which is an additional reactant of an epoxy resin with an unsaturated monoacid such as acrylic acid or methacrylic acid.

[0069] Epoxy resin as the material for epoxy (meth) acrylate includes for example diglycidyl compounds (bisphenol type epoxy resin), which is obtained by the condensation of bisphenol represented by the bisphenol such as bisphenol A and bisphenol F and epihalohydrin.Epoxy resin can include the epoxy resin with phenol skeleton.The example of the epoxy resin with phenol skeleton includes polyvalent glycidyl ether (phenol novolac type epoxy resin or cresol novolac type epoxy resin), which is obtained by the condensation of novolac and epihalohydrin, and the novolac is the condensation product of phenol or cresol and aldehyde such as formalin.The example of epoxy resin can also include the epoxy resin with cyclohexyl ring.

[0070] The epoxy (meth)acrylate suitably includes, for example, bisphenol A epoxy acrylate, which is in a solid phase or a liquid phase having a viscosity of 10 Pa·s or more at 25° C. The bisphenol A epoxy acrylate can be represented, for example, by the following formula (V):

[0071] [Chemical formula 5]

[0072]

[0073] In formula (V), n represents a positive integer.

[0074] Examples of commercially available bisphenol A type epoxy acrylates include Denacol Acrylate DA-250 (produced by Nagase ChemteX Corporation and having a melt viscosity of 60 Pa･s at 25°C), Denacol Acrylate DA-721 (produced by Nagase ChemteX Corporation and having a melt viscosity of 100 Pa･s at 25°C), Ripoxy VR-60 (produced by Showa High Polymer Co., Ltd. and which is solid at ordinary temperature), and Ripoxy VR-77 (produced by Showa High Polymer Co., Ltd. and having a melt viscosity of 100 Pa･s at 25°C).

[0075] When the acrylic compound (A) includes a compound having three or more (meth)acryloyl groups, examples of the compound having three or more (meth)acryloyl groups include pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol pentaacrylate, ethoxylated (3) trimethylolpropane triacrylate, ethoxylated (6) trimethylolpropane triacrylate, ethoxylated (9) trimethylolpropane triacrylate, propoxylated (6) trimethylolpropane triacrylate, prop ... ethoxylated (3) glyceryl triacrylate, highly propoxylated (55) glyceryl triacrylate, ethoxylated (15) trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, tetraethylene glycol diacrylate, dimethylolpropane tetraacrylate, tripropylene glycol diacrylate, pentaacrylate, 1,3-adamantanediol dimethacrylate, 1,3-adamantanediol diacrylate, 1,3-adamantanedimethanol dimethacrylate and 1,3-adamantanedimethanol diacrylate.

[0076] The acrylic compound (A) may contain, for example, 10 to 50% by mass of a (meth)acrylate having a cross-linked polycyclic structure relative to the entire acrylic compound (A). The acrylic compound (A) may also contain 3 to 20% by mass of a di(meth)acrylate having a structure in which an alkylene oxide is added to a bisphenol skeleton relative to the entire acrylic compound (A). In addition, the acrylic compound (A) may also contain 5 to 30% by mass of an epoxy (meth)acrylate relative to the entire acrylic compound (A).

[0077] In addition to the above components, the acrylic compound (A) may contain any of a variety of vinyl monomers. For example, the acrylic compound (A) may contain a monofunctional vinyl monomer.

[0078] The content of the acrylic compound (A) may be 40 parts by mass or more and 90 parts by mass or less, and preferably 30 parts by mass or more and 80 parts by mass or less, based on 100 parts by mass of the total amount of the acrylic compound (A), the polyphenylene ether resin (B) and the thermoplastic resin.

[0079] The polyphenylene ether resin (B) will be described. As described above, the polyphenylene ether resin (B) has a radical polymerizable substituent (b1) at its terminal. The polyphenylene ether resin (B) has, for example, a polyphenylene ether chain (b2) and a substituent (b1) bonded to the terminal of the polyphenylene ether chain (b2).

[0080] The substituent (b1) may have any structure without limitation as long as the substituent (b1) is radically polymerizable. Examples of the substituent (b1) include a group having a carbon-carbon double bond.

[0081] The substituent (b1) is preferably a group having a carbon-carbon double bond. In this case, reacting the substituent (b1) with the acrylic compound (A) results in the polyphenylene ether resin (B) being incorporated into the macromolecular skeleton. As a result, the cured product of the encapsulating resin composition has excellent heat resistance and moisture resistance.

[0082] The substituent (b1) may have, for example, a structure represented by the following formula (1) or a structure represented by the following formula (2):

[0083] [Chemical formula 6]

[0084]

[0085] In formula (1), R is hydrogen or an alkyl group. When R is an alkyl group, the alkyl group is suitably a methyl group.

[0086] [Chemical formula 7]

[0087]

[0088] In formula (2), n is an integer in the range of 0 to 10, and for example, n=1. In formula (2), Z is an arylene group, and R 1 To R 3 are independently hydrogen or an alkyl group. When n in the formula (2) is 0, Z is directly bonded to the terminal of the polyphenylene ether chain (c1) in the polyphenylene ether resin (C).

[0089] In particular, the substituent (b1) preferably has a structure represented by formula (1).

[0090] The polyphenylene ether resin (B) may contain, for example, a compound having a structure represented by the following formula (3):

[0091] [Chemical formula 8]

[0092]

[0093] In formula (3), Y is an alkylene group or a direct bond having 1 to 3 carbon atoms. For example, Y may be a dimethylmethylene group. In formula (3), X is a substituent (b1) and may be, for example, a group having a structure represented by formula (1) or a group having a structure represented by formula (2). It is particularly recommended that X is a group having a structure represented by formula (1). In formula (3), s is a number equal to or greater than zero, t is a number equal to or greater than zero, and the sum of s and t is a number equal to or greater than one. In formula (3), s is suitably a number in the range of 0 to 20, t is suitably a number in the range of 0 to 20, and the sum of s and t is suitably a number in the range of 1 to 30.

[0094] Relative to the total amount of 100 parts by mass of acrylic resin, polyphenylene ether and thermoplastic resin, the content of polyphenylene ether resin (B) is suitably in the range of 20% by mass to 80% by mass. If the content is more than 20% by mass, the cured product of the encapsulation resin composition can have higher heat resistance. If the content is less than 80% by mass, the cured product can have higher flexibility. The content is more suitably in the range of 25% by mass to 50% by mass.

[0095] In addition to the acrylic compound (A) and the polyphenylene ether resin (B), the encapsulation resin composition may also contain a thermosetting compound. Examples of such thermosetting compounds include compounds that cause a thermosetting reaction with the acrylic compound (A). Specific examples of such thermosetting compounds include bismaleimide resins.

[0096] The encapsulating resin composition may contain an elastomer. Examples of the elastomer include maleic anhydride adducts of isoprene polymers.

[0097] The encapsulating resin composition may contain a small amount of a thermoplastic resin. Examples of the thermoplastic resin include copolymers of methyl methacrylate and n-butyl methacrylate.

[0098] The thermal free radical polymerization initiator (C) contains, for example, an organic peroxide. The one-minute half-life temperature of the organic peroxide is suitably in the range of 100°C to 195°C, and more suitably in the range of 120°C to 180°C. In this case, in the initial stage of the step of heating and curing the encapsulating resin composition, the viscosity of the encapsulating resin composition is increased quickly enough without damaging the wettability between the protruding electrode 31 and the conductor line 21, thereby reducing the number of pores generated. In addition, the curing reaction of the encapsulating resin composition is carried out quickly enough so that the peeling between the semiconductor chip 3 and the encapsulation member 41 can be reduced.

[0099] Specific examples of organic peroxides include tert-butyl peroxy-2-ethylhexyl monocarbonate (one-minute half-life temperature of 161.4°C), tert-butyl peroxybenzoate (one-minute half-life temperature of 166.8°C), tert-butylcumyl peroxide (one-minute half-life temperature of 173.3°C), dicumyl peroxide (one-minute half-life temperature of 175.2°C), α, α'-di(tert-butylperoxy)diisopropylbenzene (one-minute half-life temperature of 175.4°C), 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane (one-minute half-life temperature of 179.8°C), di-tert-butyl peroxide (one-minute half-life temperature of 185.9°C), and 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexyne (one-minute half-life temperature of 194.3°C).

[0100] The content of the thermal free radical polymerization initiator (C) is suitably in the range of 0.25 to 2.0 parts by mass relative to 100 parts by mass of the total amount of the acrylic compound (A) and the polyphenylene ether resin (B). This imparts good physical properties to the cured product. The content of the thermal free radical polymerization initiator (C) is more suitably in the range of 0.5 to 1.5 parts by mass.

[0101] In this embodiment, it is also recommended that the encapsulation resin composition also contains an inorganic filler as component (D) (hereinafter referred to as "inorganic filler (D)"). The encapsulation resin composition containing the inorganic filler (D) further reduces the number of pores generated in the encapsulation member 41 when the gap between the base member 2 and the semiconductor chip 3 is sealed by applying ultrasonic vibration to the encapsulation resin composition while heating the encapsulation resin composition. In addition, this further reduces the possibility of the encapsulation member 41 being peeled off from the base member 2 or the semiconductor chip 3. In addition, the inorganic filler (D) makes it possible to control the thermal expansion coefficient of the encapsulation member 41 made of the cured product of the encapsulation resin composition. In addition, the inorganic filler (D) improves the thermal conductivity of the encapsulation member 41, so that the heat generated by the semiconductor chip 3 can be efficiently dissipated through the encapsulation member 41.

[0102] Examples of inorganic fillers (D) may include at least one selected from the group consisting of: silica powder, such as fused silica, synthetic silica and crystalline silica; oxides, such as aluminum oxide and titanium oxide; silicates, such as talc, calcined clay, uncalcined clay, mica and glass; carbonates, such as calcium carbonate, magnesium carbonate and hydrotalcite; hydroxides, such as aluminum hydroxide, magnesium hydroxide and calcium hydroxide; sulfates or sulfites, such as barium sulfate, calcium sulfate and calcium sulfite; borates, such as zinc borate, barium metaborate, aluminum borate, calcium borate and sodium borate; and nitrides, such as aluminum nitride, boron nitride and silicon nitride. Fused silica may be fused spherical silica or fused crushed silica. The inorganic filler (D) particularly preferably contains at least one of silica or aluminum oxide.

[0103] The inorganic filler (D) may have a pulverized, needle-like, flaky, spherical or any other suitable shape without limitation. In order to improve the dispersibility of the inorganic filler (D) in the encapsulating resin composition and to control the viscosity of the encapsulating resin composition, the inorganic filler (D) preferably has a spherical shape.

[0104] The average particle size of the inorganic filler (D) is desirably smaller than the gap distance between the base member 2 and the semiconductor chip 3 bonded to the base member 2 .

[0105] In order to increase the packing density of the inorganic filler (D) in the encapsulating resin composition and the encapsulating member 41 and to control the viscosity of the encapsulating resin composition, the average particle size of the inorganic filler (D) is suitably 5 μm or less, more suitably 1 μm or less, even more suitably 0.5 μm or less, and particularly suitably in the range of 0.1 μm to 0.3 μm.

[0106] Note that, in this embodiment, the average particle size is a median diameter calculated based on the results of particle size distribution measurement by laser beam diffraction.

[0107] In order to control the viscosity of the encapsulation resin composition and control the physical properties of the encapsulating member 41 , the inorganic filler (D) may contain two or more types of components having mutually different average particle sizes.

[0108] The inorganic filler (D) may account for, for example, 10% by mass or more and 90% by mass or less relative to the solid content of the encapsulating resin composition.

[0109] The encapsulation resin composition may contain a flux. Examples of flux include organic acids. When the encapsulation resin composition contains an organic acid, the effect of the organic acid enables the surface oxide film to be removed from the protruding electrode 31 during the reflow process, thereby ensuring good connection reliability between the semiconductor chip 3 and the base member 2. The organic acid may include at least one compound selected from the group consisting of the following: sebacic acid, abietic acid, glutaric acid, succinic acid, malonic acid, oxalic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, diglycolic acid, thiodiglycolic acid, phthalic acid, isophthalic acid, terephthalic acid, propanetricarboxylic acid, citric acid, benzoic acid and tartaric acid. Relative to the solid content of the encapsulation resin composition, the content of the organic acid suitably accounts for more than 0.1% by mass and less than 20% by mass, and more suitably more than 0.1% by mass and less than 10% by mass.

[0110] The encapsulation resin composition may contain maleic acid-modified polybutadiene. The encapsulation resin composition containing maleic acid-modified polybutadiene particularly significantly improves the adhesion between the encapsulation member 41 and the base member 2. The content of maleic acid-modified polybutadiene is preferably 10% by mass or more and 30% by mass or less of the acrylic compound (A).

[0111] The encapsulation resin composition may also contain known resin constituent components, such as epoxy compounds and phenolic compounds. Examples of epoxy compounds include at least one component selected from the group consisting of: alkylphenol novolac type epoxy resins, such as phenol novolac type epoxy resins and cresol novolac type epoxy resins; naphthol novolac type epoxy resins; phenol aralkyl type epoxy resins having a phenylene skeleton, a biphenylene skeleton, or any other skeleton; biphenyl aralkyl type epoxy resins; naphthol aralkyl type epoxy resins having a phenylene skeleton, a biphenylene skeleton, or any other skeleton; multifunctional epoxy resins, such as trisphenol methane type epoxy resins and alkyl-modified trisphenol methane type epoxy resins. esters; triphenylmethane type epoxy resins; tetraphenolethane type epoxy resins; dicyclopentadiene type epoxy resins; distilbene type epoxy resins; bisphenol type epoxy resins, such as bisphenol A type epoxy resins and bisphenol F type epoxy resins; biphenyl type epoxy resins; naphthalene type epoxy resins; alicyclic epoxy resins; bromine-containing epoxy resins, such as bisphenol A type brominated epoxy resins; glycidylamine type epoxy resins obtained by the reaction of polyamines such as diaminodiphenylmethane or isocyanuric acid with epichlorohydrin; and glycidyl ester type epoxy resins obtained by the reaction of polyacids such as phthalic acid or dimer acid with epichlorohydrin. Examples of phenolic compounds include at least one component selected from the group consisting of: phenolic resins, more specifically, novolac type resins, such as phenol novolac resins, cresol novolac resins, and naphthol novolac resins; dicyclopentadiene type phenol novolac resins, dicyclopentadiene type naphthol novolac resins, and other dicyclopentadiene type phenolic resins; terpene-modified phenolic resins; bisphenol type resins, such as bisphenol A and bisphenol F; and triazine-modified novolac resins. When the encapsulating resin composition contains an epoxy compound, the encapsulating resin composition may also contain a curing accelerator that promotes the curing of the epoxy compound.

[0112] The encapsulating resin composition may contain a radical scavenger, as long as the advantages of the embodiment are not impaired. That is to say, the encapsulating resin composition may or may not contain a radical scavenger. If the encapsulating resin composition contains a radical scavenger, then even the free radicals produced in the encapsulating resin composition when the encapsulating resin composition is heated can also be removed by the radical scavenger. This slows down the thermal free radical reaction in the encapsulating resin composition, thus suppressing the thermal free radical reaction when the encapsulating resin composition is heated and melted. This makes the reactivity of the encapsulating resin composition being heated controlled, thus making the viscosity of the encapsulating resin composition controllable.

[0113] Examples of the radical scavenger include nitrogen oxide compounds and carbonyl sulfide compounds. The encapsulating resin composition containing the nitrogen oxide compound allows the progress of the initial thermal radical reaction to be moderately slowed down when the encapsulating resin composition is melted by heating.

[0114] Examples of the nitrogen oxide compound include at least one component selected from the group consisting of: 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO); 4-acetamido-2,2,6,6-tetraethylpiperidinyl-1-oxy; 4-amino-2,2,6,6-tetramethylpiperidinyl-1-oxy; 4-carboxyl-2,2,6,6-tetramethylpiperidinyl-1-oxy; 4-oxo-2,2,6,6-tetramethylpiperidinyl-1-oxy; 4-methacryloyloxy-2,2,6,6-tetramethylpiperidinyl-1-oxy; and [[N,N'-[adamantan-2-ylidenebis(1,4-phenylene)]bis(tert-butylamine)]-N, N'-diyldioxy] radical. The content of the nitrogen oxide compound is suitably 2.5% by mass or more and 20% by mass or less relative to the thermal radical polymerization initiator (C).

[0115] In addition to the above components, the encapsulation resin composition may contain additives as long as the advantages of this embodiment are not impaired. Examples of the additives include silane coupling agents, defoaming agents, leveling agents, low stress agents, and pigments.

[0116] For example, the encapsulating resin composition can be prepared by the following method.

[0117] First, all components except the inorganic filler (D) of the above-mentioned encapsulation resin composition are mixed together simultaneously or sequentially to obtain a mixture. The mixture is then stirred and blended, while heating or cooling treatment is performed as required. Next, the inorganic filler (D) is added to the mixture as required. Afterwards, the mixture is stirred and blended again, while heating or cooling treatment is performed as required. In this way, an encapsulation resin composition can be obtained. In order to stir the mixture, for example, a disperser, a planetary mixer, a ball mill, a three-roll mill, a bead mill and other mixers can be used in combination as required.

[0118] It is also recommended to form the encapsulating resin composition into a sheet shape. In other words, the encapsulating resin composition preferably has a sheet shape. The encapsulating resin composition is suitable for making the encapsulating member 41 of the semiconductor device 1 (see FIG. 1 ).

[0119] Will refer to Figure 2 The sheet-shaped encapsulating resin composition (hereinafter referred to as "sheet member 40") and the laminated sheet 6 including the sheet member 40 are described in detail.

[0120] When making the sheet member 40, for example, first, a composition in a liquid phase is prepared by adding a solvent to the components of the encapsulation resin composition as needed. Examples of solvents include at least one component selected from the group consisting of methanol, ethanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, methyl ethyl ketone, acetone, isopropyl acetate, toluene and xylene. The amount of solvent to be added can be appropriately set. For example, relative to the entire solid content of the encapsulation resin composition, the content of the solvent can account for more than 20% by mass and less than 80% by mass. Note that when the sheet member is obtained by forming the encapsulation resin composition into a sheet shape, the solvent is volatile.

[0121] In addition, a support sheet 60 is provided. For example, the support sheet 60 may include a plastic sheet 61 of suitable polyethylene terephthalate. Optionally, the support sheet 60 may include a plastic sheet 61 and an adhesive layer 62 stacked on the plastic sheet 61. The adhesive layer 62 is a layer with an appropriate degree of adhesive force, and can be used to fasten the support sheet 60 to a suitable substrate. The adhesive layer 62 may have a reaction curing property. In this case, by curing the adhesive layer 62 after the support sheet 60 has been placed on the substrate, the support sheet 60 can be firmly fastened to a suitable substrate. For example, the adhesive layer 62 may be made of acrylic resin, synthetic rubber, natural rubber or polyimide resin.

[0122] The liquid composition is applied to one surface of the support sheet 60. If the support sheet 60 includes a plastic sheet 61 and an adhesive layer 62, the liquid composition is applied to the surface of the plastic sheet 61 opposite to the adhesive layer 62. Afterwards, the liquid composition is dried or semi-cured by heating the liquid composition on the support sheet 60. In this case, the liquid composition is heated under conditions including a heating temperature of 60°C to 120°C and a heating time of 5 to 30 minutes. This enables the sheet member 40 to be formed on the support sheet 60, and a laminated sheet 6 including the sheet member 40 and the support sheet 60 for supporting the sheet member 40 can be obtained. The encapsulation resin composition containing the polyphenylene ether resin (B) is conducive to forming the encapsulation resin composition into a sheet shape, thereby making it particularly easy to make the sheet member 40.

[0123] For example, the thickness of the sheet member 40 may be in the range of 10 μm to 50 μm. However, this is only an example and should not be construed as limiting. Alternatively, the sheet member 40 may have any other suitable thickness selected according to the thickness of the encapsulation member 41 of the semiconductor device 1 .

[0124] Optionally, as Figure 2 As shown, the laminated sheet 6 may further include a protective film 64 covering the sheet member 40. The material used for the protective film 64 is not particularly limited. Figure 2As shown, if the support sheet 60 includes the adhesive layer 62, the laminated sheet 6 may further include a coating sheet 63 covering the adhesive layer 62. The material used for the coating sheet 63 is also not particularly limited.

[0125] The cured product is obtained by thermally curing the encapsulating resin composition. The cured product of the encapsulating resin composition is suitably used as an encapsulating member for hermetically sealing the gap between the base member 2 and the semiconductor chip 3 bonded to the base member 2. The encapsulating resin composition placed in the gap between the base member 2 and the semiconductor chip 3 is heated and ultrasonically vibrated. Thus, even when the encapsulating member 41 is made of the encapsulating resin composition by curing, the number of pores generated in the encapsulating member 41 is still reducible.

[0126] The glass transition temperature of the cured product is preferably equal to or higher than 100° C. and more preferably equal to or higher than 150° C. In this case, the cured product can have high heat resistance, and therefore, the semiconductor device 1 including the encapsulation member 41 made of the cured product can have excellent heat resistance reliability. When the encapsulation resin composition contains the polyphenylene ether resin (B), such a glass transition temperature can be easily achieved by appropriately controlling the composition of the encapsulation resin composition.

[0127] The encapsulating resin composition can be effectively used as an underfill material. The semiconductor device 1 can be manufactured by pre-applying the encapsulating resin composition for underfill to hermetically seal the gap between the base member 2 and the semiconductor chip 3 .

[0128] Figure 1A An example of a semiconductor device 1 is shown. The semiconductor device 1 includes a base member 2, a semiconductor chip 3 bonded face-down to the base member 2, and an encapsulation member 41 that hermetically seals the gap between the base member 2 and the semiconductor chip 3. The encapsulation member 41 is a cured product of an encapsulation resin composition. The semiconductor chip 3 includes a protruding electrode 31 on its surface facing the base member 2. Meanwhile, the base member 2 has a conductor line 21 on its surface facing the semiconductor chip 3. The protruding electrode 31 and the conductor line 21 are aligned with each other and connected together by solder bumps 32. These protruding electrodes 31 and the conductor line 21 are embedded in the encapsulation member 41.

[0129] The method for manufacturing a semiconductor device 1 according to the embodiment includes providing a base member 2 having a conductor line 21, an encapsulation resin composition, and a semiconductor chip 3 having a protruding electrode 31. The method also includes: arranging the semiconductor chip 3 having the protruding electrode 31 on one surface of the base member 2 having the conductor line 21, and the encapsulation resin composition is interposed between the semiconductor chip 3 and the base member 2 so that the conductor line 21 faces the protruding electrode 31. The method also includes applying ultrasonic vibration to the encapsulation resin composition while heating the encapsulation resin composition in this state to hermetically seal the gap between the base member 2 and the semiconductor chip 3 and electrically connect the conductor line 21 to the protruding electrode 31. In this way, a semiconductor device 1 can be manufactured in which the gap between the base member 2 and the semiconductor chip 3 is sealed with an encapsulation member 41 having a reduced number of pores.

[0130] Next, we will refer to Figure 3A –3D An exemplary method for manufacturing the semiconductor device 1 is described in more detail.

[0131] First, the base member 2, the semiconductor chip 3, and the encapsulation resin composition are provided.

[0132] For example, the base member 2 can be a motherboard, a packaging board or an interposer board. In this embodiment, the base member 2 includes an insulating substrate made of glass epoxy, polyimide, polyester, ceramic or any other suitable material, and a conductor track 21 made of an electrical conductor such as copper formed on its surface.

[0133] The semiconductor chip 3 includes a protruding electrode 31, which is electrically connected to a circuit formed on one surface of a silicon wafer by an appropriate method such as a photolithography process. In this embodiment, the protruding electrode 31 of the semiconductor chip 3 includes a solder bump 32. Alternatively, it is not the protruding electrode 31 but the conductor line 21 on the base member 2 that can include the solder bump 32. Still alternatively, the protruding electrode 31 and the conductor line 21 can each include a solder bump 32. In other words, at least one of the protruding electrode 31 of the semiconductor wafer or the conductor line 21 of the base member 2 can include a solder bump 32. The solder bump 32 is suitably made of a lead-free solder having a melting point of more than 210°C, such as Sn-3.5Ag (melting point of 221°C), Sn-2.5Ag-0.5Cu-1Bi (melting point of 214°C), Sn-0.7Cu (melting point of 227°C) or Sn-3Ag-0.5Cu (melting point of 217°C).

[0134] The semiconductor chip 3 can be formed by a single sheet that has been cut into a suitable size from a stack of laminated sheets 6 and semiconductor wafers. Specifically, a single sheet can be obtained in the following manner. For example, first, the sheet member 40 of the laminated sheet 6 can be stacked on the surface of the semiconductor wafer with the raised electrode 31. In this case, after the protective film 64 is peeled off from the sheet member 40 of the laminated sheet 6, the sheet member 40 stacked on the support sheet 60 is further stacked on the surface of the semiconductor wafer with the raised electrode 31. Next, the semiconductor wafer is cut into small pieces by cutting the semiconductor wafer while the sheet member 40 is still attached to the semiconductor wafer. In this case, for example, after the coating sheet 63 is peeled off from the adhesive layer 62 of the support sheet 60, the adhesive layer 62 can be placed on the substrate and then cured as needed. In this way, the support sheet 60 is fixed to the substrate when the sheet member 40 is stacked on the support sheet 60. In this state, the semiconductor wafer is cut while the sheet member 40 is still attached to the semiconductor wafer. As a result, a plurality of components (hereinafter referred to as "chip components") are obtained, each of which includes the semiconductor chip 3 that has been cut out from the semiconductor wafer and the single sheet that has been cut out from the sheet component 40. Then, each chip component is removed from its supporting sheet 60. In each chip component, its semiconductor chip 3 includes the protruding electrodes 31, and the single sheet is superimposed on the surface of the semiconductor chip 3 having the protruding electrodes 31.

[0135] Next, the semiconductor chip 3 is bonded face-down onto the base member 2 with the encapsulation resin composition interposed between the base member 2 and the semiconductor chip 3. In this embodiment, Figure 3A As shown, the bonding process is performed in the following manner: a flip chip bonder 70 including a bonding head 71 and a workbench 72 is used and has the ability to apply ultrasonic vibrations. Note that in this embodiment, the flip chip bonder 70 is configured so that its bonding head 71 is capable of applying ultrasonic vibrations. However, this is merely an example and should not be construed as limiting. Alternatively, the flip chip bonder 70 may have any other configuration as long as the flip chip bonder 70 is capable of applying ultrasonic vibrations to the encapsulation resin composition. For example, the workbench 72 may have the ability to apply ultrasonic vibrations. Specific examples of the flip chip bonder 70 include FCB3 manufactured by Panasonic Corporation. In addition, in Figure 3AIn FIG. 3D and in the previous description, the encapsulation resin composition should be pre-stacked on the semiconductor chip 3. However, this is only an example and should not be construed as limiting. Alternatively, for example, in a case where the base member 2 is placed on the workbench 72 and the semiconductor chip 3 is held by the bonding head 71, the encapsulation resin composition as the sheet member 40 may be interposed between the base member 2 and the semiconductor chip 3. In this case, for example, the encapsulation resin composition may be interposed between the base member 2 and the semiconductor chip 3 by applying the encapsulation resin composition to the base member 2.

[0136] like Figure 3A As shown in FIG. 1 , the base member 2 having the conductor line 21 is made by a workbench 72, and the semiconductor chip 3 is held by a bonding head 71 so that the protruding electrodes 31 of the semiconductor chip 3 face the base member 2 supported on the workbench 72. On the other hand, the encapsulating resin composition is interposed between the base member 2 and the semiconductor chip 3. In this state, as Figure 3B As shown, the bonding head 71 is moved toward the workbench 72. This enables the semiconductor chip 3 to be placed at an appropriate position on the base member 2 while interposing the encapsulating resin composition therebetween. At this time, the semiconductor chip 3 is aligned with the base member 2 so that the protruding electrodes 31 of the semiconductor chip 3 are superimposed on the conductor lines 21 of the base member 2.

[0137] In this state, while heating the encapsulating resin composition, the semiconductor chip 3 and the base member 2, ultrasonic vibration is applied to the encapsulating resin composition, the semiconductor chip 3 and the base member 2 by the bonding head 71 and the workbench 72, thereby heating the solder bump 32 and the encapsulating resin composition. The heating temperature can be appropriately set according to the composition of the solder bump 32 and the composition of the encapsulating resin composition or the reaction start temperature of the encapsulating resin composition. As described above, the heating temperature is suitably in the range of 100°C to 150°C.

[0138] The duration of applying ultrasonic vibration and the frequency of vibration can be appropriately set. For example, ultrasonic vibration can be applied for a duration in the range of 0.1 seconds to 5.0 seconds, and the frequency of vibration can be in the range of 10 kHz to 80 kHz.

[0139] Optionally, when ultrasonic vibration is applied to the encapsulation resin composition, the semiconductor chip 3 and the base member 2 by the bonding head 71 and the workbench 72, the encapsulation resin composition, the semiconductor chip 3 and the base member 2 are heated, and the load can be applied to the base member 2, the semiconductor chip 3 and the encapsulation resin composition on the workbench 72 by the bonding head 71. For example, the bonding head 71 can be configured to apply pressure toward the workbench 72. This makes it possible to apply a load by pressing the pressure bonding head 71 on the semiconductor chip 3 when the encapsulation resin composition is between the base member 2 and the semiconductor chip 3. In this case, the conditions for applying the load can be appropriately set. For example, the applied load can be in the range of 10 N to 200 N.

[0140] As can be seen, with the encapsulating resin composition interposed between the base member 2 and the semiconductor chip 3, ultrasonic vibration is applied to the solder bump 32 and the encapsulating resin composition while heating the solder bump 32 so that the solder bump 32 melts, thereby electrically connecting the bump electrode 31 to the conductor line 21. In addition, as Figure 3C As shown, after the encapsulation resin composition has once been melted, it is thermally cured, thereby enabling the formation of the encapsulation member 41. In this way, the gap between the semiconductor chip 3 and the base member 2 is hermetically sealed with the encapsulation member 41.

[0141] Afterwards, if Figure 3D As shown, the bonding head 71 is lifted upward and removed from the semiconductor chip 3 .

[0142] Bonding the semiconductor chip 3 to the base member 2 in this way enables obtaining Figure 1A The semiconductor device 1 shown. As can be seen, according to this embodiment, even when the temperature of the bonding head 71 is set to a lower temperature, the gap between the base member 2 and the semiconductor chip 3 can be sealed with the encapsulation member 41. In addition, in the encapsulation member 41 thus formed of the encapsulation resin composition, the amount of residual voids has been reduced as described above.

[0143] Optionally, after the semiconductor device 1 is manufactured as described above, the same flip chip bonder 70 can be used again to continuously manufacture the semiconductor device 1. In this embodiment, the encapsulation resin composition has a unique viscosity behavior and has a low viscosity within a certain temperature range. This is conducive to setting the heating temperature during the bonding process, so that the temperature of the bonding head 71 can be set to a lower temperature. This is why even when it is necessary to continuously manufacture a plurality of semiconductor devices 1 by repeatedly repeating the same process, the time for cooling the bonding head 71 can be eliminated or significantly reduced. This will improve the productivity of the semiconductor device 1.

[0144] In a variation of this embodiment, Figure 1B As shown, the semiconductor device 1 can also be implemented as a semiconductor device 1 having a multi-level stacking structure, in which the encapsulation members 41 and the semiconductor chips 3 are alternately stacked on the base member 2. In order to produce a semiconductor device 1 having such a multi-level stacking structure, as in the above-mentioned embodiment, after the semiconductor chips 3 are stacked on the base member 2 with the encapsulation members 41 made of the encapsulation resin composition interposed therebetween, the same flip-chip bonder 70 can be used to heat and ultrasonically vibrate another semiconductor chip 3 and another encapsulation resin composition again, so that the latter (another) semiconductor chip 3 is stacked on the previous (already stacked) semiconductor chip 3 with the other encapsulation member 41 interposed therebetween. Repeating this process repeatedly makes it possible to produce a semiconductor device 1 having such a multi-level stacking structure, in which the encapsulation members 41 and the semiconductor chips 3 are alternately stacked on the base member 2 in sequence. Figure 1B In the illustrated exemplary semiconductor device 1 , semiconductor chips are stacked one on top of another in four stages. However, the number of stacked semiconductor chips is not necessarily four, but may be appropriately set according to the application, intended use, or any other factors.

[0145] According to this variation of the exemplary embodiment, not only can the heating temperature be set to a lower temperature, but also the time for cooling the bonding head 71 of the flip chip bonder 70 can be eliminated or significantly reduced. This will improve productivity even when manufacturing the semiconductor device 1 having such a multi-stage stack structure. Example

[0146] 1. Preparation of Examples 1-5 and Comparative Examples 1-4

[0147] Examples 1 to 5 and Comparative Examples 1 to 4 of encapsulating resin compositions were prepared in the following manner.

[0148] First, the components shown in the "Composition" column of Table 1 are provided. Among these components, first, an acrylic compound is weighed and stirred and blended together with a disperser. Afterwards, all components except the polyphenylene ether resin and the inorganic filler are added to the mixture of the acrylic compound and blended with it to prepare a first mixture solution. During this period, a second mixture solution is prepared by dissolving the polyphenylene ether resin in methyl ethyl ketone. The first mixture and the inorganic filler are added to the second mixture, and they are stirred with a disperser, and then blended together in a bead mill to disperse the inorganic filler. In this way, an encapsulation resin composition is prepared. The concentration of methyl ethyl ketone in the encapsulation resin composition is adjusted to be in the range of 30% by mass to 50% by mass.

[0149] The details of each component shown in the "Composition" column of Table 1 are as follows:

[0150] ● Modified polybutadiene: maleic acid-modified polybutadiene, produced by Cray Valley Co., Ltd., product name Ricobond 1756;

[0151] ● Acrylic compound 1: ethoxylated bisphenol A dimethacrylate, produced by Shin Nakamura Chemical Co., Ltd., product number BPE-100;

[0152] ●Acrylic compound 2: bisphenol A epoxy acrylate, Showa High Polymer Co., Ltd., product number VR-77;

[0153] ● Acrylic compound 3: tricyclodecane dimethanol diacrylate, produced by Shin Nakamura Chemical Co., Ltd., product number A-DCP;

[0154] ● Acrylic compound 4: trimethylolpropane triacrylate, produced by Shin-Nakamura Chemical Co., Ltd., product number A-TMPT;

[0155] ● Polyphenylene ether resin: modified polyphenylene ether resin, produced by SABIC, product number SA9000, and having a structure represented by formula (3), wherein X is a group having a structure represented by formula (1) (R is a methyl group);

[0156] ● Thermal free radical polymerization initiator: dicumyl peroxide, produced by NOF CORPORATION, product name Percumyl D;

[0157] ●Thermoplastic resin: copolymer of methyl methacrylate and n-butyl methacrylate, produced by Evonik Japan, product name DYNACOLL AC2740;

[0158] ●Inorganic filler 1 (filler): silicon dioxide powder, produced by Tokuyama Corporation, product number NMH-24D, average particle size 0.24 μm;

[0159] ●Inorganic filler 2 (filler): produced by Admatechs, product number SO-C2, average particle size 0.5 μm;

[0160] ● Nitrogen oxide compound: 2,2,6,6-tetramethyl-1-piperidinyloxy free radical, produced by Tokyo Chemical Industry Co., Ltd.;

[0161] ●Silane coupling agent: 3-glycidyloxypropyltrimethoxysilane, produced by Shin-Etsu Chemical Co., Ltd., product number KBM-403; and

[0162] ●Flux: sebacic acid.

[0163] 2. Evaluation test

[0164] The encapsulating resin compositions were subjected to the following evaluation tests. The results of these evaluation tests are summarized in Table 1.

[0165] (1) Measurement of melt viscosity and evaluation of reaction onset temperature

[0166] The temperature dependence of their melt viscosity was measured using a rheometer (model AR2000ex) manufactured by TA Instruments Inc. under the conditions of a temperature range of 100–300°C, a heating rate of 60°C / min, and an angular velocity of 0.209 rad / s. In this way, a melt viscosity curve was obtained, which respectively shows the relationship between the temperature and melt viscosity of the relevant encapsulating resin composition in the encapsulating resin composition. The reaction start temperature of each encapsulating resin composition is obtained by detecting the minimum melt viscosity from its melt viscosity curve, and finding the temperature of the melt viscosity 50 Pa･s higher than the minimum melt viscosity. In addition, using the reaction start temperature as a reference, the melt viscosity at the reaction start temperature, the maximum melt viscosity at a temperature equal to or higher than 40 °C lower than the reaction start temperature and equal to or lower than the reaction start temperature, and the melt viscosity at a temperature 50 °C lower than the reaction start temperature are determined, and the melt viscosity at a predetermined temperature is shown in their corresponding predetermined columns in Table 1.

[0167] (2) Evaluation of glass transition temperature

[0168] A film of polyethylene terephthalate was provided as a support sheet. A film of the encapsulation resin composition was deposited on the support sheet using a rod coater to obtain a wet film thickness of 100 μm, which was then heated at 80°C for 30 minutes. In this way, a sheet member having a thickness of 50 μm was formed on the support sheet. A plurality of sheet members were stacked on top of each other, compressed with a vacuum laminator, cured by heating in an oven at 150°C for two hours, and then cut to produce a sample having a size of 4 mm × 40 mm and a thickness of 800 mm in a plan view.

[0169] The glass transition temperature of the sample was measured using a thermomechanical analyzer (TMA) manufactured by Seiko Instruments Inc. (Model SS7100) under conditions including a tensile force of 49 mN and a temperature program of 5°C / min at temperatures of 30°C to 300°C.

[0170] (3) Porosity evaluation

[0171] A semiconductor device was produced using the encapsulating resin composition in the following manner.

[0172] Walts TEG IP80 (10 mm×10 mm×300 μm) produced by WALTS Co., Ltd. was provided as a base member.

[0173] As a semiconductor wafer, Walts TEG CC80 (7.3 mm × 7.3 mm × 100 μm) produced by WALTS Co., Ltd. was provided. The semiconductor wafer included 1,048 bump electrodes, each of which included a Cu column with a height of 30 μm and a solder bump with a height of 15 μm stacked thereon, and the pitch between adjacent solder bumps was 80 μm.

[0174] A film of polyethylene terephthalate was provided as a support sheet. A film of the encapsulation resin composition was deposited on the support sheet using a bar coater to obtain a wet film thickness of 100 μm, and then heated at 80° C. for 30 minutes. In this way, a sheet member having a thickness of 45 to 55 μm was formed on the support sheet.

[0175] The sheet member is stacked on the semiconductor wafer, the assembly is fixed to a cutting frame, and the sheet member is cut into small pieces using a dicing saw manufactured by DISCO Corporation (product name: DFD6341) with the silicon wafer still attached to the sheet member, thereby cutting out a plurality of chip members having a size of 7.3 mm × 7.3 mm × 100 μm, each chip member including a semiconductor chip and a single sheet having an encapsulation resin composition.

[0176] As a flip chip bonder with the ability to apply ultrasonic vibration, a flip chip bonder of model FCB3 manufactured by Panasonic Corporation is used. In the case of a heated workbench of the flip chip bonder, the base member is fixed to the workbench. The chip member is held by the bonding head of the flip chip bonder, and the bonding head is heated. In such a state, the bonding head is brought closer to the workbench, and a single sheet of the chip member is stacked on the base member when the raised electrodes of the semiconductor chip are aligned with the conductor lines on the base member. The temperature of the workbench is set to 145°C and the temperature of the bonding head is set to 115°C so that the heating temperature of the encapsulation resin composition is 130°C. In this state, ultrasonic vibration is applied while the flip chip bonder is pressed against the semiconductor chip and a load toward the base member is applied on the semiconductor chip. The load was applied under the following conditions: a load of 10 N was applied for 0.1 seconds from the start of the load application, a load of 50 N was applied at a time point of 0.2 seconds from the start of the load application, and a load of 50 N was maintained from a time point of 0.2 seconds from the start of the load application to a time point of 1.0 seconds from then on. Ultrasonic vibrations were applied starting at a time point of 0.5 seconds from the start of the load application so that an output reached 3 W at a time point of 0.6 seconds from the start of the load application, and from a time point of 0.6 seconds from the start of the load application to a time point of 1.0 seconds from then on, the output was maintained at 3 W. When 1.0 seconds had passed from the start of the load application, the load application was stopped, and the bonding head was removed from the table.

[0177] Afterwards, the encapsulation resin composition between the base member and the semiconductor chip is heated at a temperature of 150°C for one hour to fully cure, thereby obtaining a semiconductor device to be tested. The semiconductor device 1 is checked using a scanning acoustic tomography device (scanning acoustic tomograph, SAT) to check whether there are any pores in the encapsulation member of the semiconductor device. When no pores are detected from the encapsulation member, the semiconductor device to be tested is evaluated as "A". On the other hand, when any pores are detected from the encapsulation member, the semiconductor device to be tested is evaluated as "C".

[0178] (4) Evaluation of connectivity

[0179] Using the encapsulation resin composition, a semiconductor device for testing is prepared by the same method as in the case of (3) porosity evaluation. The connectivity of the semiconductor device is evaluated in the following manner. Specifically, the semiconductor device is cut and its exposed cross section is polished. The gap distance between the Cu column of the semiconductor chip and the conductor line of the base member exposed on the cross section by means of the solder bump is measured. When the gap distance is found to be less than 5 μm, the semiconductor device for testing is evaluated as "A". When the gap distance is in the range of 5 μm to less than 10 μm, the semiconductor device for testing is evaluated as "B". When the gap distance is found to be more than 10 μm, the semiconductor device for testing is evaluated as "C".

[0180] (5) Evaluation of peelability

[0181] Using the encapsulation resin composition, a semiconductor device for testing was prepared by the same method as in the case of (3) porosity evaluation. The semiconductor device was checked using a scanning acoustic tomography device (SAT) to see if any peeling was observed at the interface between the cured product, the semiconductor chip, and the base member. When no peeling was observed, the semiconductor device for testing was evaluated as "A". When any peeling was observed, the semiconductor device for testing was evaluated as "C".

[0182]

[0183] Reference numerals list

[0184] 1Semiconductor device

[0185] 2 Base member

[0186] 21 conductor line

[0187] 3Semiconductor Chips

[0188] 31 Raised electrode

[0189] 40 sheet components

[0190] 41 Encapsulation member

[0191] 6-Laminated Sheet

Claims

1. An encapsulation resin composition for airtightly sealing a gap between a base member and a semiconductor chip bonded to the base member, wherein The encapsulation resin composition comprises: An acrylic compound as component (A); A polyphenylene ether resin as component (B), the polyphenylene ether resin comprising a polyphenylene ether chain (b2) and a substituent (b1) having a free radical polymerization property bonded to a terminal of the polyphenylene ether chain (b2); and The reaction starting temperature of the encapsulating resin composition is below 160°C, and The melt viscosity of the encapsulating resin composition When the reaction starting temperature is 200 Pa･s or less, 400 Pa･s or less at any temperature that is equal to or higher than a temperature 40°C lower than the reaction starting temperature and equal to or lower than the reaction starting temperature, and It is 1,000 Pa·s or less at a temperature 50°C lower than the reaction start temperature. 2 . The encapsulating resin composition according to claim 1 , further comprising an inorganic filler as component (D).

3. The encapsulating resin composition according to claim 1 or 2, wherein The encapsulating resin composition has a sheet shape.

4. A laminated sheet, comprising: The encapsulation resin composition according to claim 3; and A supporting sheet for supporting the encapsulating resin composition thereon. 5 . A cured product obtained by thermally curing the encapsulating resin composition according to claim 1 .

6. The cured product according to claim 5, wherein The glass transition temperature of the cured product is equal to or higher than 100°C.

7. A semiconductor device, comprising: Base member; a semiconductor chip bonded face-down onto the base member; and an encapsulation member for hermetically sealing a gap between the base member and the semiconductor chip, The encapsulating member is made of the cured product according to claim 5 or 6.

8. A method for manufacturing a semiconductor device, the method comprising: Arranging a semiconductor chip having a protruding electrode on one surface of a base member having a conductor line, while interposing the encapsulation resin composition according to any one of claims 1 to 3 between the semiconductor chip and the base member so that the conductor line faces the protruding electrode; and Ultrasonic vibration is applied to the encapsulating resin composition while the encapsulating resin composition is heated to cure the encapsulating resin composition and electrically connect the conductor line to the bump electrode.

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