JP5604873B2 - Manufacturing method of electronic device - Google Patents

Description

[Description of related applications]
The present invention is based on the priority claim of Japanese Patent Application No. 2007-283681 (filed on Oct. 31, 2007), the entire contents of which are incorporated herein by reference. Shall.
The present invention relates to a method of manufacturing an electronic device, a method of manufacturing an electronic device (e.g., a semiconductor device), particularly the electronic device (e.g., semiconductor element) was flip-chip mounted.

  In recent years, mounting techniques for electronic devices, particularly semiconductor devices, are required to be smaller and thinner, improve signal transmission speed, and increase the number of pins. For this reason, wire bonding technology has been used to connect a semiconductor element and a substrate, but in recent years, there is a flip chip technology that can shorten the connection distance and increase the number of electrodes and is suitable for downsizing and thinning. It is used. The most common flip-chip technique is to electrically connect a semiconductor element and a substrate by directly facing a solder bump formed on the semiconductor element to an electrode of the substrate. In order to protect the connection part after flip-chip mounting, a thermosetting resin is usually filled between the semiconductor element and the substrate.

  However, flip chip mounting also has manufacturing challenges. For example, with the miniaturization of the electrode pitch, it is necessary to increase the alignment accuracy between the substrate electrode and the semiconductor element bump. Further, the resin filled between the substrate and the semiconductor element contains a large amount of filler for lowering the thermal expansion coefficient in order to prevent generation of defects due to thermal expansion. Therefore, the filling rate of the resin is lowered. Therefore, various techniques have been studied for these problems.

  For example, Patent Document 1 and Patent Document 2 disclose techniques for increasing the alignment accuracy of flip chip mounting.

  In the semiconductor device described in Patent Document 1 in which the semiconductor element is flip-chip mounted, the land of the mounting substrate that is electrically bonded to the bump of the semiconductor element has a diameter larger than the diameter of the bump, and the bump is a side wall. The hole formed in the taper shape so that it may contact a part is formed. Further, in Patent Document 1, as a method for mounting the semiconductor device, a method of forming an insulating resin film on the mounting substrate surface before electrical bonding between the semiconductor element and the mounting substrate, and the semiconductor element and the mounting substrate are electrically connected. A method of filling an insulating resin after mechanical joining has been disclosed.

  In the semiconductor chip mounting substrate in the semiconductor chip mounting method described in Patent Document 2, a through-hole penetrating the outermost insulating layer is formed in the semiconductor chip mounting position so that the bump can be inserted. In the through hole, wiring for connecting to the bump is provided, and the outermost insulating layer is made of a thermoplastic resin. The semiconductor chip is flip-chip mounted so that bumps are inserted into the through holes of the substrate.

  Techniques for improving resin filling properties are disclosed in, for example, Patent Document 3 and Patent Document 4.

  In the method for forming an interelectrode connection structure described in Patent Document 3, a resin film is laminated so as to cover the electrodes of a semiconductor chip, and a laser or photolithography is used on the resin film at a position corresponding to the electrodes. An opening is formed. Next, after filling the opening with a metal paste, alignment is performed so that the metal paste and the electrode of the mounting substrate face each other, and a semiconductor chip is mounted on the mounting substrate. Next, by performing heat treatment, the electrode of the semiconductor chip and the electrode of the mounting substrate are electrically connected, and the semiconductor chip and the mounting substrate are bonded by curing of the resin film.

  In the method for connecting integrated circuit elements described in Patent Document 4, metal bumps that can be elastically deformed are formed on at least one of electrode pads of the integrated circuit elements or electrode terminals of the substrate. After applying the resin to at least one of the integrated circuit element or the substrate, the resin at a position corresponding to the metal bump is removed. The integrated circuit element and the substrate are electrically connected by elastically deforming the metal bumps by pressing the electrode pad and the electrode terminal opposite to each other and crimping the integrated circuit element and the substrate.

Japanese Patent Laid-Open No. 10-189655 JP 2005-183924 A JP 2003-204148 A Japanese Patent Laid-Open No. 5-36761

Note that the entire disclosure of Patent Documents 1-4 is incorporated herein by reference. The following analysis is given by the present invention.
The following analysis is given from the perspective of the present invention.

  In the mounting method described in Patent Document 1 in which an insulating resin film is formed before the semiconductor element and the mounting substrate are bonded, the insulating resin remains between the bumps of the semiconductor element and the land of the mounting substrate. There is a risk of lack of sex. On the other hand, in the method of filling the insulating resin film after bonding the semiconductor element and the mounting substrate, it takes time to fill the resin because of the filler contained in the resin.

  In the mounting method described in Patent Document 2, there is a void in the through hole where the bump and the wiring are electrically connected, and the connection portion cannot be protected with resin.

  In the forming method described in Patent Document 3, a metal paste is used, but the metal paste has high electrical resistance and low connection reliability. Moreover, when solder powder is used for the metal paste, flux is required. However, since the surroundings are covered with resin and the flux cannot be washed, the substance contained as a flux component remains in the vicinity of the electrode as a metal salt, which may cause problems such as electromigration and ion migration. There is.

  In the connection method described in Patent Document 4, it is difficult to remove the resin in accordance with the shape and dimensions of the metal bumps. For example, voids and connection failures occur due to variations in the photolithography process. For example, if an opening larger than the metal bump is formed, a void is generated around the bump. If a small opening is formed so that the metal bump does not enter, a resin is formed between the metal bump and the electrode. It is bitten and electrical connection cannot be obtained.

An object of the present invention is to provide a method of manufacturing a flip chip mounting electronic device with high electrical connection reliability .

According to a first aspect of the present invention, a method for manufacturing an electronic device in which an electronic element is flip-chip mounted on a mounting substrate is provided. The method of manufacturing the electronic device includes a resin coating step of covering the surface of the substrate having electrodes formed thereon with a resin, and at least a part of the width of the electrode in the electrode direction so that at least a part of the electrode is exposed. Forming an opening having a tapered surface that is reduced in size, forming a bump having a tapered surface in which at least a part of the width is reduced outward from the electronic device, an electrode and the bump And a connecting step of electrically connecting the two. The width of the widest part of the opening formed in the opening forming process is wider than the width of the tip of the bump formed in the bump forming process, and the center in the height direction of the part where the width of the bump formed in the bump forming process is reduced Narrower than the width at the part. The angle of the taper surface of the opening formed in the opening forming step is larger than the angle of the taper surface of the bump formed in the bump forming step with respect to the electrode. In the connecting process, the electrodes and the bumps are electrically connected so as to widen the openings with the bumps.

According to a second aspect of the present invention, a method of manufacturing an electronic device in which an electronic element is flip-chip mounted on a mounting substrate is provided. The method of manufacturing the electronic device includes a resin coating step of covering the surface of the substrate having electrodes formed thereon with a resin, and at least a part of the width of the electrode in the electrode direction so that at least a part of the electrode is exposed. An opening forming step of forming an opening having a tapered surface that is reduced to at least, a metal film forming step of forming a metal film on at least a part of the inner wall of the opening and an exposed surface of the electrode in the opening, and at least a part of the electronic device A bump forming step of forming a bump having a tapered surface whose width is reduced outward from the electronic element, and a connecting step of electrically connecting the electrode and the bump. The width of the widest part of the opening formed in the opening forming process is wider than the width of the tip of the bump formed in the bump forming process, and the center in the height direction of the part where the width of the bump formed in the bump forming process is reduced Narrower than the width at the part. The angle of the taper surface of the opening formed in the opening forming step is larger than the angle of the taper surface of the bump formed in the bump forming step with respect to the electrode. In the connecting step, the electrodes and the bumps are electrically connected by heating while contacting the bumps and the metal film.

  According to a preferred embodiment of the second aspect, the metal film includes a seed layer and a plating layer.

According to a preferred mode of the second aspect, the metal film forming step includes a step of forming a seed layer, a step of forming on the seed layer by electrolytic plating the plating layer.

According to a preferred form of the second aspect, the metal film forming step further includes a step of removing the seed layer other than the portion where the metal film is to be formed using the plating layer as a mask.

  According to a preferred form of the first and second viewpoints, the connecting step includes at least one of a position adjusting step for aligning the bump and the opening, and an electronic element or a mounting substrate until the tip of the bump contacts the electrode. And a pressing step of pressing one against the other, and a heating step in which the bump and the electrode are metal-bonded and the resin is heated so as to be deformed according to the bump.

According to the preferable form of the first and second viewpoints, the heating step includes a first heating step for deforming the resin according to the bump, and a second heating step for metal bonding of the bump and the electrode. ,including.

  According to a preferred form of the first and second viewpoints, in the position adjusting step, one of the mounting board and the electronic element is directed upward and the other is directed downward, and at least one of the mounting board and the electronic element is held. Then, at least one of the bumps and the resin or metal film is moved until the bumps and the resin or metal film come into contact with each other to adjust the relative positions of the bumps and the resin or metal film. In the pressing step, after releasing at least one of the holdings, the one released from holding is pressed.

  According to the preferable form of the first and second viewpoints, in the heating step, the resin is heated by heating from the electronic element side.

According to the preferred form of the first and second viewpoints, at least a part of the mounting board side of the bump formed in the bump forming step has a conical shape or a truncated cone shape whose diameter decreases from the electronic element side toward the mounting board. It is.

According to the preferred form of the first and second viewpoints, in the connecting step, the electrode and the bump are arranged such that at least the conical tip or the truncated cone-shaped exposed bottom of the bump is electrically connected to the electrode. Are electrically connected .

  According to the preferable form of the first viewpoint and the second viewpoint, the opening formed in the opening forming step has a conical shape or a truncated cone shape whose diameter is reduced in the electrode direction.

  The present invention has at least one of the following effects.

  According to the present invention, a bump having a width wider than the opening is fitted into the opening of the resin having a tapered surface, thereby generating voids in the connection portion between the electronic element and the mounting substrate and the resin between the bump and the electrode. Biting can be prevented. Thereby, the electrical connection reliability between the electronic element and the mounting board in the electronic device can be improved.

  According to the present invention, by interposing the metal film between the bump and the inner wall of the resin opening, it is possible to increase the reliability of electrical connection between the electronic element and the mounting substrate in the electronic device.

  According to the present invention, an opening having a tapered surface is formed in advance before flip-chip mounting, so that the electronic element and the mounting substrate can be easily and accurately aligned.

  According to the present invention, the load applied during mounting can be kept low by deforming the bump having the tapered surface. Thereby, a reliable electronic device with little damage can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional process diagram for explaining an electronic device, a manufacturing method thereof, and a mounting substrate according to a first embodiment of the present invention. 4 is a flowchart of a mounting process in the electronic device according to the first embodiment of the present invention. FIG. 6 is a schematic cross-sectional process diagram for explaining an electronic device, a manufacturing method thereof, and a mounting board according to a second embodiment of the present invention. The flowchart of the mounting process in the electronic device which concerns on 2nd Embodiment of this invention. The schematic cross-sectional process drawing of the process of producing the mounting substrate of this invention among the manufacturing methods of the electronic device which concerns on 3rd Embodiment of this invention. The schematic cross-sectional process drawing which shows another process of the manufacturing method of the electronic device which concerns on 3rd Embodiment of this invention. FIG. 4D is a schematic process cross-sectional view according to a fourth embodiment corresponding to the processes of FIGS. 1D to 1E according to the first embodiment. The schematic process sectional drawing concerning 4th Embodiment corresponding to Drawing 3 (g)-Drawing 3 (h) process concerning a 2nd embodiment.

1, 11 Electronic device (semiconductor device)
2, 12, 22 Mounting substrate 3, 13 Electronic element (semiconductor element)
4, 14, 24 Wiring board 5, 15, 25 Electrode 6, 16, 26 Resin 6a, 16a, 26a Opening 6b, 16b Electronic element side resin 6c, 16c Mounting board side resin 7, 17 Electrode 8, 18 Bump 19, 29 Metal film 20, 30 Resist 29a Plating layer (second metal film)
29b Seed layer (first metal film)

  An electronic device, a manufacturing method thereof, and a mounting substrate according to a first embodiment of the present invention will be described. In the present embodiment, a semiconductor device using a semiconductor element as an electronic element, a manufacturing method thereof, and a mounting substrate will be described as an example of the electronic device. FIG. 1 is a schematic cross-sectional process diagram for explaining the method for manufacturing a semiconductor device according to the first embodiment. 1A to 1C are steps for producing a mounting substrate used in the mounting method of the present invention, and FIGS. 1D to 1E are steps for mounting a semiconductor element on the mounting substrate. is there.

  First, a wiring board 4 having an electrode 5 formed on at least one surface is prepared (FIG. 1A).

  Next, a resin 6 that seals a joint portion between the semiconductor element to be mounted and the wiring board is applied to the surface on which the electrode 5 is formed (resin coating step, FIG. 1B). The thickness of the resin 6 on the wiring board 4 is set in consideration of the bump height and volume of the semiconductor element to be mounted, the volume of the opening formed in the next process, the deformation of the bump at the time of mounting, and the like. Thereafter, the resin 6 is temporarily cured in a drying furnace.

  Next, in accordance with the position of the electrode 5, an opening (through hole) 6a is formed in the resin 6 so that at least a part of the electrode 5 is exposed (opening forming step, FIG. 1 (c)). The mounting substrate 2 is produced. For the formation of the opening 6a, for example, a photolithography technique by exposure / development can be applied. The opening 6 a has a tapered shape (preferably a truncated cone shape) such that at least a part of the width is reduced toward the electrode 5. The width d1 of the widest portion (outer surface side) of the opening 6a (the diameter when the shape along the substrate surface of the opening 6a is circular) is the width of the tip of the bump 8 of the semiconductor element to be mounted (FIG. 1D). Of d2). The width d1 of the widest portion of the opening 6a is the width of the widest portion of the bump 8 of the semiconductor element (or the diameter when the shape of the bump along the semiconductor element surface is circular) (d3 in FIG. 1D). ), And preferably narrower than the width of the central portion of the bump 8 of the semiconductor element in the height direction (d4 in FIG. 1D). Thereby, when the bump 8 and the electrode 5 are joined, the opening 6 a can be expanded by the taper shape of the bump 8.

  Further, the width of the narrowest portion of the opening 6a (the width (diameter) d5 of the exposed surface of the electrode 5 in FIG. 1D) is the same as the width (diameter) (d2) of the tip of the bump 8, or the bump 8 It is preferable to be smaller than the width (diameter) d2 of the tip. Thereby, the inhibitory effect with respect to generation | occurrence | production of a void can be heightened. However, even when the resin 6 enters the bonding interface, the width d5 of the narrowest portion of the opening 6a is such that the metal bonding area has the minimum area that can sufficiently obtain mechanical strength and temperature cycle reliability. May be larger than the width d2 of the tip of the bump 8.

  Further, the inclination angle of the taper of the opening 6 a is preferably larger than the inclination angle of the taper of the bump 8. That is, the angle α of the tapered surface of the opening 6 a with respect to the electrode 5 is preferably larger than the angle β of the tapered surface of the bump 8 with respect to the electrode 5. Thereby, the inhibitory effect with respect to generation | occurrence | production of a void can be heightened.

  Note that the width of the bump 8 and the width of the opening 6a are the widths before flip-chip mounting (that is, before deformation).

  Next, the semiconductor element 3 is mounted on the mounting substrate 2. FIG. 2 shows a flowchart of the mounting process of the electronic device according to the first embodiment.

  First, bumps 8 are formed on the electrodes 7 of the semiconductor element 3 (bump forming step). The bump 8 has a tapered shape (preferably a cone shape or a truncated cone shape) in which at least a part of the width is reduced from the electrode 7 toward the outside. The width of the bump 8 is set so as to obtain a relative relationship with the width of the opening 6a as described above.

  Next, the relative position between the semiconductor element 3 and the mounting substrate 2 is adjusted so that the bumps 8 are inserted into the openings 6a (position adjusting step; FIG. 1 (d), S1). Preferably, the mounting substrate 2 and the semiconductor element 3 are moved while holding at least one of the mounting substrate 2 and the semiconductor element 3 with one side facing upward and the other facing downward. For example, it arrange | positions so that the opening 6a may become upward, and it moves, adsorbing | holding and holding the semiconductor element 3 so that the bump 8 may face downward, and the position of the bump 8 and the opening 6a is aligned (S2). When it is detected from the load and / or position that the bump 8 is in contact with the resin 6 of the mounting substrate 2 (S3), the holding of the semiconductor element 3 is released (for example, the suction holding is stopped) (S4), and the semiconductor element 3 is Be able to move freely in the substrate surface direction (lateral direction).

  Next, in this state, the semiconductor element 3 is pushed in the direction of the mounting substrate 2 until the tip of the bump 8 contacts the electrode 5 (primary load; S5). Thereby, the bump 8 is guided to the electrode 5 according to the opening 6a, and the semiconductor element 3 can be aligned with the mounting substrate 2 with high accuracy. At this time, the presence or absence of heating is determined according to the type of the resin 6, and heating is performed so that at least the resin 6 does not flow even when heated. This is because if the resin 6 flows, the resin may enter the bonding interface between the bumps 8 and the electrodes 5 and an electrical connection may not be formed. Therefore, when the resin 6 can be deformed until the bump 8 and the electrode 5 come into contact with each other without being heated, it is preferable to push the semiconductor element 3 without heating, and the resin 6 cannot be deformed without being heated. In such a case, it is preferable that the semiconductor element 3 is pushed in by heating to a temperature at which the resin 6 is softened (below the temperature at which it is fluidized).

  The contact between the tip of the bump 8 and the electrode 5 is, for example, control of a load applied to the semiconductor element 3 (or the mounting substrate 2), detection (control) of a relative position between the semiconductor element 3 and the mounting substrate 2, or a semiconductor element 3 (or mounting substrate 2) can be obtained by controlling the moving distance. By these, metal joining can be stabilized.

  Next, heating is performed while maintaining the contact between the bump 8 and the electrode 5 (S6). As a result, the tips of the bumps 8 and the electrodes 5 are metal-bonded, and the resin 6 is caused to flow and deform along the shapes of the semiconductor element 3 and the bumps 8 and are brought into close contact. For example, the resin 6 can be heated by heating from the semiconductor element 3 side. Then, the resin 6 is cured by further heating, and the manufacture of the semiconductor device 1 is completed (FIG. 1 (e), S7).

  According to the present embodiment, it is possible to prevent the occurrence of voids at the connection portion between the semiconductor element 3 and the mounting substrate 2. In addition, the resin 6 can be prevented from intervening between the bumps 8 of the semiconductor element 3 and the electrodes 5 of the mounting substrate 2. Further, the alignment between the semiconductor element 3 and the mounting substrate 2 can be easily performed.

  As the resin 6, any resin can be used as long as it seals the connection portion between the mounting substrate 2 and the semiconductor element 3. For example, the resin 6 can be a resin having photosensitivity and thermosetting. As the resin 6 having a sealing function having photosensitivity and thermosetting, a resin composition containing an active energy ray-curable resin and an active energy ray polymerization initiator can be used.

  Any active energy ray-curable resin may be used as long as it is cured by irradiation with active energy rays such as ultraviolet rays, electron beams, and X-rays, and the cured product exhibits adhesive curability by heat treatment. Specifically, for example, a phenol novolac type epoxy resin, a cresol novolac type epoxy resin, a glycidylamine type epoxy resin, a biphenyl type epoxy resin, an epoxy resin having a fluorene skeleton, and bromides thereof exhibiting curability by irradiation with active energy rays An epoxy resin such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, monomethyl maleate, monopropyl maleate, monobutyl maleate, sorbic acid, etc. What was esterified by making it react in the range of 0.5-1.5 by an epoxy equivalent ratio is used suitably. A particularly preferred unsaturated basic acid is acrylic acid. Among them, in the present invention, epoxy resins having a fluorenyl group as a skeleton obtained by reacting an epoxy resin having a fluorene skeleton and an epoxy resin such as bromide thereof with (meth) acrylate are particularly preferable. The epoxy resin having a fluorene skeleton has, for example, the structure described in the claims of Japanese Patent Publication No. 7-91365, more specifically, the third page of the same publication, page 3, left column 35 to page 3. Examples include those described in the right column, line 1 and the same example, and EFS300 manufactured by Nippon Steel Chemical Co., Ltd. can be used as an example. A circuit board obtained using the epoxy resin having the fluorene skeleton is preferable because it has excellent physical properties, particularly heat resistance, surface hardness, and toughness, as described in the publication. In order to make the active energy ray-curable resin thus obtained alkali-developable, phthalic acid, phthalic anhydride, maleic acid, maleic anhydride, oxalic acid, adipic acid, citric acid and the like are further added to the resin. A polybasic acid may be reacted. In this case, the acid value of the obtained resin is preferably 20 to 150. Active energy ray polymerization initiators generate radicals upon irradiation with active energy rays, and can promote polymerization of active energy ray-curable resins by the physical properties of the initiator itself such as hydrogen abstraction reaction and radical cleavage reaction. . Representative examples of the hydrogen abstraction type are benzophenones. Examples of radical cleavage types include benzyl dimethyl ketals. Furthermore, thioxanthone compounds are also used. Specifically, benzophenone, 4,4′-dimethylaminobenzophenone, 4,4′-diethylaminobenzophenone, 2-ethylanthraquinone, tert-butylanthraquinone, benzoin ethyl ether, benzoin isopropyl ether, 2,2-dimethoxy-2-phenyl There are acetophenone, 2,2-diethoxyacetophenone, 2-chlorothioxanthone, diethylthioxanthone, 2-hydroxy-2-methylpropiophenone, 4-isopropyl-2-hydroxy-2-methylpropiophenone, among these It is preferable to mix | blend 1 type (s) or 2 or more types in the ratio of 3-20 weight% with respect to active energy ray curable resin solid content. As the diluent, a photopolymerizable monomer or an organic solvent can be used. Representative photopolymerizable monomers include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, N-vinylpyrrolidone, acryloylmorpholine, methoxytetraethylene glycol acrylate, methoxypolyethylene glycol acrylate, polyethylene glycol diacrylate, N , N-dimethylacrylamide, N-methylolacrylamide, N, N-dimethylaminopropyl acrylamide, N, N-dimethylaminoethyl acrylate, N, N-dimethylaminopropyl acrylate, melamine acrylate, or methacrylates corresponding to the above acrylates, etc. Water-soluble monomers, and diethylene glycol diacrylate, triethylene glycol diacrylate, propylene glycol Diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, phenoxyethyl acrylate, tetrahydrofurfuryl acrylate, dicyclohexyl acrylate, trimethylolpropane diacrylate, trimethylolpropane triacrylate, glycerin diglycidyl ether di Acrylate, glycerin triglycidyl ether triacrylate, pentaerythritol triacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, isoborneolyl acrylate, cyclopentadiene mono- or di-acrylate or methacrylates corresponding to the acrylate, Polybase Mono- and hydroxyalkyl (meth) acrylate -, di -, tri - there is a water-insoluble monomers or more polyesters. This copolymerizable monomer can be blended in an amount of 10 to 60% by weight, preferably 20 to 40% by weight, based on the solid content of the active energy ray-curable resin. This active energy ray curable resin is usually practically used in the form of a coating solution dissolved in an organic solvent, and known solvents are used, for example, ethylene glycol monoethyl ether, ethylene glycol mono One or more of ethyl ether acetate, ethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, methyl ethyl ketone, methyl isobutyl ketone, 1,1,1-trichloroethane, trichloroethylene, etc. It can be used by mixing. A thermosetting component having an epoxy group such as a phenol novolac type epoxy resin, a cresol novolac type epoxy resin, or a bisphenol A type epoxy resin is preferably used as an adhesion improver. This thermosetting component can be blended in an amount of 5 to 40% by weight, preferably 10 to 30% by weight, based on the solid content of the active energy ray curable resin.

  The resin 6 can also contain a filler as appropriate in order to adjust the expansion coefficient. However, since the photosensitive resin is used and the lithography technique is applied, it is necessary to adjust the content ratio so as not to reduce the resolution (so that a desired opening can be obtained). For example, the filler content is preferably set to 10% to 30%.

  In FIG. 1, the shape of the bump 8 is not changed, but this does not mean that the bump 8 is not deformed during mounting.

  Next, an electronic device, a manufacturing method thereof, and a mounting substrate according to a second embodiment of the present invention will be described. FIG. 3 is a schematic cross-sectional process diagram for explaining the method for manufacturing the electronic device according to the second embodiment. Also in the present embodiment, a semiconductor element is used as an electronic element, as in the first embodiment. FIGS. 3A to 3C are the same as FIGS. 1A to 1C according to the first embodiment.

  Next, a metal film 19 is formed on the resin 16 surface (including the inner wall of the opening 16a) and on the exposed surface of the electrode 15 by electroless plating (FIG. 3D). The metal film 19 is electrically connected to the electrode 15. Next, the portion where the metal film 19 is left in the opening 16a is protected with a resist 20 (FIG. 3E). The portion where the metal film 19 is left is at least a part of the exposed surface of the electrode 15 and the inner wall of the opening 16a. Further, the metal film 19 formed on the exposed surface of the electrode 15 and the metal film 19 formed on the inner wall of the opening 16a are electrically connected (integrated). Next, after removing unnecessary portions of the metal film 19 by etching, the resist 20 is removed, and the mounting substrate 12 is manufactured (FIG. 3F).

  The relative relationship between the form (shape, dimensions, etc.) of the openings formed by the openings 16a or the metal film 19 and the form (shape, dimensions, etc.) of the bumps 18 of the semiconductor element 13 is the same as in the first embodiment. .

  Next, the semiconductor element 13 is mounted on the mounting substrate 12. FIG. 4 shows a flowchart of the mounting process of the electronic device according to the second embodiment. S11 to S14 in FIG. 4 are the same as S1 to S4 in FIG.

  FIG. 3G is the same as FIG. 1D according to the first embodiment from S11 to S14 in FIG. Next, the semiconductor element 13 is pushed in a predetermined amount (up to a predetermined position) or a predetermined load in the direction of the mounting substrate 12 to increase the contact area between the bump 18 and the metal film 19 (S15). When the semiconductor element 13 is pushed in, it is preferable not to heat before the contact between the bump 18 and the metal film 19 is ensured. This is because, if the resin 16 flows due to heating, the shape of the metal film 19 is not maintained, so that sufficient contact between the bumps 18 and the metal film 19 cannot be obtained. Accordingly, it is preferable that the resin 16 has an appropriate hardness, and it is preferable to increase the contact area between the bump 18 and the metal film 19 while plastically deforming the bump 18 by pressing or by deforming the resin 16 without heating. .

  The contact between the bump 18 and the metal film 19 is, for example, control of a load applied to the semiconductor element 13 (or the mounting substrate 12), detection (control) of the relative position between the semiconductor element 13 and the mounting substrate 12, or the semiconductor element 13 (Or can be obtained by controlling the movement distance of the mounting substrate 12). Preferably, the semiconductor element 13 is moved toward the mounting substrate 12 by a predetermined amount.

  Next, while maintaining the contact between the bump 18 and the metal film 19 (preferably further increasing the contact area), primary heating is performed until the resin 16 flows (S16). As a result, the resin 16 is deformed according to the bumps 18 to increase the metal contact with the metal film 19 and to suppress the generation of voids. In the second embodiment, since the metal film 19 is formed, the resin 16 does not enter the bonding interface between the bump 18 and the metal film 19 even when the resin 16 is heated to a temperature at which the resin 16 flows.

  Next, secondary heating is performed while maintaining pressure so that the bumps 18 and the metal film 19 are metal-bonded and the resin 16 is cured (S17), thereby completing the manufacture of the semiconductor device 11 (FIG. 3). (H), S18).

  According to this embodiment, the metal film 19 and the bump 18 can be firmly bonded, and generation of voids can be prevented. Moreover, since the electrical contact area in the bump 18 is increased as compared with the first embodiment, the reliability of electrical connection can be improved. Further, as in the first embodiment, the alignment of the semiconductor element 13 and the mounting substrate 12 can be easily performed.

  Next, a method for manufacturing an electronic device according to the third embodiment of the present invention will be described. FIG. 5 shows a schematic cross-sectional process diagram of a process of manufacturing a mounting substrate according to the third embodiment in the method for manufacturing an electronic device according to the third embodiment of the present invention. In the present embodiment, the metal film is formed by plating after forming the seed layer. FIGS. 5A to 5C are the same as FIGS. 1A to 1C according to the first embodiment.

  Next, a seed layer 29b (first metal film) for supplying power for electrolytic plating is formed on the surface of the resin 26 (including the inner wall of the opening 26a) and on the exposed surface of the electrode 25 by sputtering (FIG. 5D). )). Next, a plating layer 29a (second metal film) is grown on the seed layer 29b by electrolytic plating to form the metal film 29 (FIG. 5E).

  A resist 30 is formed in the same manner as in FIG. 3E according to the second embodiment (FIG. 5F). Next, similarly to FIG. 3F according to the second embodiment, unnecessary portions of the plating layer 29a are removed by etching, and then the resist 30 is removed (FIG. 5G). Next, using the remaining plating layer 29a as a mask, the seed layer 29b exposed from the plating layer 29a is removed, and the mounting substrate 22 is manufactured (FIG. 5H).

  The process of mounting the semiconductor element on the mounting substrate 22 is the same as that of the second embodiment (FIG. 3G to FIG. 3H and FIG. 4).

  Further, the metal film 29 can be formed in another process. FIG. 6 is a schematic cross-sectional process diagram showing another process of the electronic device manufacturing method according to the third embodiment of the present invention. After the seed layer 29b is formed in the same manner as in FIG. 5D (FIG. 6A), a resist 30 is formed in addition to the portion where the plating layer 29a is formed (FIG. 6B). Next, a plating layer 29a is formed on the seed layer 29b by electrolytic plating (FIG. 6C). Next, after removing the resist 30 (FIG. 6D), the seed layer 29b is removed using the plating layer 29a as a mask (FIG. 6E).

  In the present embodiment, the plating layer is formed by electrolytic plating, but may be formed by electroless plating.

  Next, a method for manufacturing an electronic device according to the fourth embodiment of the present invention will be described. In the present embodiment, resin is also formed in advance on the electronic element surface facing the mounting substrate. The resin exposes at least part of the tip side of the taper portion of the bump. In the present embodiment, the first embodiment and the second embodiment will be described as an example. FIG. 7 is a schematic process cross-sectional view according to the present embodiment corresponding to the processes of FIGS. 1 (d) to 1 (e) according to the first embodiment. FIG. 8 is a schematic process cross-sectional view according to the present embodiment corresponding to the processes of FIGS. 3G to 3H according to the second embodiment.

  In the first embodiment to the third embodiment, the present embodiment is based on the relationship between the thickness of the resin of the mounting substrate, the shape and volume (dimension) of the opening, and the shape and volume (dimension) of the bump. When the semiconductor element is mounted, it is useful when the capacity of the resin formed on the mounting substrate is not sufficient to seal the gap between the mounting substrate and the semiconductor element. Therefore, according to the present embodiment, the insufficient resin can be compensated by forming the resin on the semiconductor element side in advance before mounting.

  For example, as shown in FIGS. 7 and 8, resins 6b and 16b are formed on the surfaces of the semiconductor elements 3 and 13 around the bumps so that the tips of the bumps 8 and 18 are exposed (FIGS. 7A and 8). (A)). Next, when the semiconductor elements 3 and 13 and the mounting boards 2 and 12 are joined, the resins 6b and 16b of the semiconductor elements 3 and 13 and the resins 6c and 16c of the mounting boards 2 and 12 are integrated. The resins 6 and 16 of the semiconductor devices 1 and 11 can be used.

  In the present embodiment, it is preferable that the depths of the openings 6a and 16a be at least large enough to guide the bumps 8 and 18 during bonding.

  As for the material of the bump and the metal film (plating film) in each of the above embodiments, Au is the most stable and highly reliable and preferable. Other materials may be Cu, Ni, Ag, Al, or alloys centered on these. The bump and the metal film (plating film) are not necessarily the same type of material. Further, bonding reliability may be improved by supplying a small amount of a material that diffuses and reacts with a bump or a metal film (plating film) to the bottom of the opening and is accompanied by a solid phase or liquid phase reaction.

  In addition, as a material for the seed layer in each of the above embodiments, for example, titanium (Ti), titanium tungsten (TiW), chromium (Cr), or the like can be used. Examples of the seed layer / metal film combination include Ti / Au, Ti / (Ni / Au), TiW / Au, TiW / Cu, TiW / (Cu / Ni / Au), Cr / Cu, and Cr / (CrCu / Cu) or the like can be used.

  In addition, the heating process for curing the resin is performed by heating a plurality of electronic devices together with another device (for example, a thermostat) after the metal bonding between the bump and the electrode or the metal film is completed. The resin of the device may be cured all at once.

  In the above-described embodiments, the present invention has been described by taking a semiconductor element as an example of the electronic element in the present invention. Can be applied to.

  Although this invention was demonstrated based on the said embodiment, it cannot be overemphasized that a various change, a deformation | transformation, improvement, etc. are included in the scope of the present invention, without being limited to the said embodiment. Further, various combinations, substitutions or selections of the disclosed elements are possible within the scope of the present invention.

  Further problems, objects, and developments of the present invention will become apparent from the entire disclosure of the present invention including the claims.

Claims (12)

  A method of manufacturing an electronic device in which an electronic element is flip-chip mounted on a mounting substrate,
  A resin coating step of covering the surface of the substrate with electrodes formed on the surface with a resin;
  An opening forming step of forming an opening having a tapered surface in which at least a part of the width is reduced in the electrode direction so that at least a part of the electrode is exposed;
  A bump forming step of forming a bump having a taper surface in which at least a part of the width of the electronic element is reduced outward from the electronic element;
  A connection step of electrically connecting the electrode and the bump,
  The width of the widest portion of the opening formed in the opening forming step is wider than the width of the tip of the bump formed in the bump forming step, and the width of the bump formed in the bump forming step is reduced. Narrower than the width in the center of the height direction of
  The angle of the tapered surface of the opening formed in the opening forming step with respect to the electrode is larger than the angle of the tapered surface of the bump formed in the bump forming step with respect to the electrode,
  A method of manufacturing an electronic device, wherein the electrode and the bump are electrically connected so as to expand the opening with the bump in the connecting step.   A method of manufacturing an electronic device in which an electronic element is flip-chip mounted on a mounting substrate,
  A resin coating step of covering the surface of the substrate with electrodes formed on the surface with a resin;
  An opening forming step of forming an opening having a tapered surface in which at least a part of the width is reduced in the electrode direction so that at least a part of the electrode is exposed;
  Forming a metal film on at least a part of an inner wall of the opening and an exposed surface of the electrode in the opening; and
  A bump forming step of forming a bump having a taper surface in which at least a part of the width of the electronic element is reduced outward from the electronic element;
  A connection step of electrically connecting the electrode and the bump,
  The width of the widest portion of the opening formed in the opening forming step is wider than the width of the tip of the bump formed in the bump forming step, and the width of the bump formed in the bump forming step is reduced. Narrower than the width in the center of the height direction of
  The angle of the tapered surface of the opening formed in the opening forming step with respect to the electrode is larger than the angle of the tapered surface of the bump formed in the bump forming step with respect to the electrode,
  A method of manufacturing an electronic device, wherein the electrode and the bump are electrically connected by heating while contacting the bump and the metal film in the connecting step. The method of manufacturing an electronic device according to claim 2, wherein the metal film includes a seed layer and a plating layer. The metal film forming step includes a step of forming the seed layer by electrolytic plating the plating layer of an electronic device according to claim 3, characterized in that it comprises a step you formed on the seed layer Production method. 5. The electronic device manufacturing method according to claim 3 , wherein the metal film forming step further includes a step of removing the seed layer other than a portion where the metal film is to be formed using the plating layer as a mask. Method.   The connecting step includes
  A position adjusting step for aligning the positions of the bump and the opening;
  A pressing step of pressing at least one of the electronic element or the mounting substrate against the other until the tip of the bump contacts the electrode;
  A heating step of metal bonding the bump and the electrode, and heating so that the resin is deformed according to the bump;
The manufacturing method of the electronic device as described in any one of Claims 1-5 characterized by the above-mentioned. The heating process includes a first heating process for deforming the resin according to the bumps, and a second heating process for metal bonding between the bumps and the electrodes. 6. A method for manufacturing an electronic device according to 6 .   In the position adjustment step, the bump and the resin or the metal film are held while holding at least one of the mounting substrate and the electronic element with one of the mounting substrate and the electronic element facing upward and the other facing downward. Adjust the relative position of each other by moving at least one until
  The method for manufacturing an electronic device according to claim 6, wherein, in the pressing step, after releasing at least one of the holdings, the one that has been released from the holding is pressed.   The method for manufacturing an electronic device according to any one of claims 6 to 8, wherein in the heating step, the resin is heated by heating from the electronic element side. At least a portion of the mounting board side of the bumps formed in the bump forming step, claim 1, characterized in that from the electronic device side, which is conical or frustoconical diameter decreases toward the mounting substrate method of manufacturing an electronic device according to any one of 1-9.   In the connecting step, the electrode and the bump are electrically connected so that at least a conical tip or a truncated cone-shaped exposed bottom of the bump is electrically connected to the electrode. The method for manufacturing an electronic device according to claim 10.   The method for manufacturing an electronic device according to claim 1, wherein the opening formed in the opening forming step has a conical shape or a truncated cone shape whose diameter decreases in the electrode direction.

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