JP2011205424A - Mounting structure for electronic component - Google Patents

Abstract

An electronic component mounting structure and a method for manufacturing the electronic component are provided that can prevent the deterioration of the electronic component characteristics by preventing the influence of outgas.
A mounting structure 2 of an electronic component 1 in which the electronic component 1 is mounted on a base material 3 having connection electrodes 33 and 34. The electronic component 1 includes a functional piece 11 having a predetermined function, a resin protruding portion 24 whose surface is covered with coating films 25 and 26 including a conductive portion electrically connected to the functional piece 11, and a resin protruding portion The resin exposed portions 27 and 28 are partially exposed. The resin exposed portions 27 and 28 hold the electronic component 1 on the base material 3 in a state where the conductive portions in the coating films 25 and 26 are in conductive contact with the connection electrodes 33 and 34.
[Selection] Figure 2

Description

  The present invention relates to an electronic component mounting structure.

  For example, in an electronic component including a functional piece such as a crystal resonator, an excitation electrode provided on the crystal resonator and a connection electrode for connecting to a drive circuit that drives the crystal resonator are in conductive contact with a conductive paste such as solder. It is fixed in a state (see, for example, Patent Document 1). When such a conductive paste is used, for example, when an impact such as a drop impact is applied, the connection portion between the crystal resonator and the connection electrode may be damaged, which is a factor of reducing connection reliability.

JP-A-11-261360

  Therefore, the bump electrode composed of the elastic core portion and the conductive film provided on the surface of the core portion is provided on the excitation electrode, and the bump electrode and the connection electrode are electrically conductively contacted through the adhesive. A component mounting structure is also conceivable. However, when such a bump electrode is employed, there is a possibility that the vibration characteristics of the crystal resonator are changed by the outgas generated from the adhesive, and the reliability is lowered.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an electronic component mounting structure that can prevent deterioration of electronic component characteristics by preventing the influence of outgas.

  In order to solve the above problems, an electronic component mounting structure according to the present invention is an electronic component mounting structure in which an electronic component is mounted on a substrate having a connection electrode, and the electronic component has a predetermined function. And the surface is covered with a coating film including a functional piece having a conductive portion electrically connected to the functional piece, and at least a portion excluding the outer peripheral portion is exposed from the coating film, and at least a bonding function is provided on the surface. A resin protrusion including a resin exposed portion, and the coating film is in conductive contact with the connection electrode, and the resin exposed portion is in contact with a part of the substrate. An electronic component is mounted on the substrate.

  According to the electronic component mounting structure of the present invention, the resin protrusion covered with the coating film is used as an electrical contact, and the resin exposed portion functions as an adhesive to maintain a good conduction state. A structure in which an electronic component is mounted on a substrate is obtained. Here, since the resin protrusion except for the resin exposed portion is covered with the coating film, the influence of outgas generated from the resin can be prevented. Further, the resin exposed portion is sealed by being surrounded by the coating film and the connection electrode of the base material. Thereby, the influence of the outgas generated from the resin exposed portion can be prevented. Therefore, it is possible to prevent deterioration of the characteristics of the electronic component due to outgassing. Moreover, since the resin protrusion has elasticity, even when an external impact is applied, the addition to the conductive portion can be reduced, and excellent conductive reliability can be obtained.

  In the electronic component mounting structure, the functional piece is preferably a crystal piece. In the present invention, the electronic component constitutes a crystal resonator including a crystal piece. Therefore, as described above, the vibration characteristics of the crystal resonator due to outgas are prevented from being deteriorated, and the crystal resonator has high conduction reliability.

  In the electronic component mounting structure, it is preferable that the coating film is formed of at least two layers, and the undercut amount of the lower layer relative to the outermost layer is equal to or greater than the film thickness of the lower layer. According to this configuration, the outermost layer of the coating film can be securely adhered to the connection electrode, and the resin exposed portion can be reliably sealed.

  In the electronic component mounting structure, it is preferable that the coating film is constituted by an electrode layer provided on the functional piece. If it does in this way, a coating film can be formed with an electrode layer at the time of manufacture of electronic parts, and a manufacturing process can be simplified.

It is a figure which shows the cross-sectional structure of a crystal oscillator package. It is a top view of FIG. It is the figure which looked at the quartz oscillator from the lower part. It is a figure which shows the AA 'line arrow cross-section structure in FIG. It is a figure which shows the formation process of a bump electrode and an adhesion part.

  Embodiments of the present invention will be described below with reference to the drawings. In each drawing used for the following description, the scale of each member is appropriately changed to make each member a recognizable size.

  FIG. 1 is a view showing a crystal resonator package to which an electronic component mounting structure according to the present invention is applied. FIG. 1 is a diagram illustrating a cross-sectional configuration of a crystal resonator package, FIG. 2 is a plan view of FIG. 1, and FIG. 3 is a diagram of the crystal resonator viewed from below. FIGS. 4A and 4B are cross-sectional configuration diagrams corresponding to the arrows AA ′ in FIG. 3 and are diagrams for explaining the shape of the bump electrode.

  As shown in FIGS. 1 and 2, a crystal resonator package (electronic component mounting structure) 2 includes a crystal resonator (electronic component) 1, a container (base material) 3 for sealing the crystal resonator 1, It has. As shown in FIGS. 1 to 3, the crystal resonator 1 includes a crystal piece (functional piece) 11, a pair of excitation electrodes 12 and 13 that excite the crystal piece 11, a bump electrode 14, and a resin exposed portion 15. It has.

  As will be described in detail later, the container 3 is formed with connection electrodes 33 and 34 used for electrical connection with the crystal unit 1 and terminal electrodes 35 and 36 when mounted on a circuit board (not shown). ing.

  The crystal piece 11 is a plate-like member having a substantially U shape in a plan view and having a tuning fork type planar shape in which two arm portions 22 and 23 extend in parallel in the same direction from the base portion 21. Each of the pair of excitation electrodes 12 and 13 is formed of a conductive material such as Al (aluminum) or Au (gold), and is formed on one surface of the crystal piece 11. The excitation electrode 12 is formed from the base portion 21 to the arm portion 22 on one surface of the crystal piece 11. The excitation electrode 13 is formed from the base 21 to the arm 23 on one surface of the crystal piece 11.

  The bump electrode 14 is formed on one surface of the base 21 and is provided in a state of being electrically connected to the excitation electrodes 12 and 13. As shown in FIGS. 1 and 3, the bump electrode 14 includes a protruding resin core part (resin protruding part) 24 and a pair of conductive films (covering films) 25 formed on the surface of the resin core part 24. 26 and resin exposed portions 27 and 28 in which the resin core portion is exposed. The resin exposed portions 27 and 28 have an adhesive function at least on the surface.

  The conductive films 25 and 26 are formed by patterning after film formation by sputtering, for example. In the present embodiment, the Au / Cr layer formed by sputtering is patterned so as to be continuous with the excitation electrodes 12 and 13 and is electrically connected to the excitation electrodes 12 and 13. That is, the crystal resonator package 2 uses the bump electrode 14 as an electrical contact between the crystal resonator 1 and the container 3.

  The conductive films 25 and 26 are made of, for example, Au (gold), TiW (titanium / tungsten), Cu (copper), Cr (chromium), Ni (nickel), Ti, W, NiV (nickel / vanadium), Al, You may form with metals and alloys, such as Pd (palladium) and lead-free solder, these single layers, or what laminated | stacked multiple types.

  As shown in FIG. 2, the resin core portion 24 has a substantially round shape in plan view, and the conductive films 25 and 26 that cover the resin core portion 24 also have a round shape. Further, the resin core portion 24 has a substantially semicircular cross-sectional shape by melting a resin pattern after patterning a resin material by a photolithography technique or an etching technique as will be described later.

  Since the resin core portion 24 is covered with the conductive films 25 and 26 as described above, various resin materials can be used. For example, polyimide resin, acrylic resin, phenol resin, silicone resin, silicone-modified polyimide resin, epoxy resin, etc. The photosensitive insulating resin or the thermosetting insulating resin is used (in this embodiment, an epoxy resin is used).

  Furthermore, at least a portion (substantially semicircular apex portion) excluding the outer peripheral portion of the resin core portion 24 (bump electrode 14) has resin exposed portions 27 and 28 where the resin core portion 24 is exposed from the conductive film, At least the surfaces of the resin exposed portions 27 and 28 have an adhesive function. As shown in FIG. 1, the resin exposed portions 27 and 28 are formed in a state where the resin core portion 24 constituting the bump electrode 14 is in conductive contact with the surface shapes of connection electrodes 33 and 34 described later. It can be mounted (held) on the container body 31. As shown in FIG. 1, the crystal unit 1 has a cantilever support structure in which a base 21 is supported by a container 3.

  Various materials can be used for the resin exposed portions 27 and 28 as long as the materials have adhesiveness at least on the surface. Specifically, in the present embodiment, the resin exposed portions 27 and 28 are made of the same material (epoxy resin) as the resin core portion 24. It is composed. The resin exposed portions 27 and 28 may be configured by separately forming an adhesive layer having adhesiveness on the surface of a resin that does not function as an adhesive.

  As shown in FIG. 4A, the conductive film is preferably formed of at least two layers, and the amount of undercut of the lower layer relative to the outermost layer is preferably equal to or greater than the thickness of the lower layer. Specifically, the undercut amount W in FIG. 4A is set to be equal to or greater than the lower layer thickness t. As a result, as shown in FIG. 4B, when the resin core portion 24 constituting the bump electrode 14 is brought into conductive contact with the connection electrodes 33 and 34 described later, the outermost undercut portion of the connection electrodes 33 and 34 is formed. By deforming according to the shape, it is possible to ensure stable electrical connection between the conductive films 25 and 26 and the connection electrodes 33 and 34 and to ensure that the resin exposed portions 27 and 28 are sealed.

  The container 3 includes a container body 31 and a lid body 32 that covers the container body 31. The container body 31 is formed in a substantially box shape, and is formed of an insulating material such as ceramics. Connection electrodes 33 and 34 are formed on the upper surface of the bottom of the container body 31. Terminal electrodes 35 and 36 for mounting on a circuit board (not shown) or the like are formed on the bottom surface of the bottom of the container body 31. Each of the connection electrodes 33 and 34 is configured, for example, by laminating an Au film on a Ni plating layer formed on a W film, and is connected to a terminal electrode via a wiring (not shown) formed on the container body 31. 35 and 36 are connected to each other. The lid 32 is formed of an insulating material such as ceramics, for example, similarly to the container body 31. The lid 32 is joined to the opening of the container main body 31 by brazing or the like, and seals the crystal unit 1 in a space formed between the lid 32 and the container main body 31.

  As described above, the crystal resonator package 2 according to the present embodiment can mount the crystal resonator 1 on the container 3 while using the bump electrode 14 as an electrical contact to maintain a good conduction state by the bonding portion. it can. Since the resin core portion 24 is covered with the conductive films 25 and 26, it is possible to prevent a problem that outgas generated from the resin core portion 24 deteriorates the vibration characteristics of the crystal resonator 1 (crystal piece 11). Further, as shown in FIG. 1, the resin exposed portions 27 and 28 are brought into close contact with the conductive films 25 and 26 by the undercut portion being deformed following the surface shape of the connection electrodes 33 and 34. That is, the resin exposed portions 27 and 28 are hermetically sealed by being surrounded by the bump electrode 14. Thereby, the malfunction that the outgas generated from the resin exposure parts 27 and 28 reduces the vibration characteristic of the crystal oscillator 1 (crystal piece 11) can be prevented.

  As described above, according to the crystal resonator package 2 according to the present embodiment, it is possible to prevent deterioration in the characteristics of the crystal resonator 1 (electronic component) due to outgas generated from the resin material, and it is highly reliable. Can provide. In addition, since both the resin core portion 24 and the adhesive portion have elasticity, it is possible to reduce the addition of the bump electrode 14 and the connection electrodes 33 and 34 to the conductive portion even when an external impact is applied. Excellent conduction reliability can be obtained. In addition, since the bump electrode can be manufactured by a photolithography technique, the electrode can be made smaller than the conventional conductive paste.

  As an embodiment of the electronic component manufacturing method of the present invention, a process of manufacturing the crystal unit package 2 (crystal unit 1) will be described. The present embodiment is characterized in the step of forming the bump electrode 14 and the bonding portion. Therefore, below, it demonstrates centering on the method of manufacturing the bump electrode 14 and an adhesion part.

  First, as shown in FIG. 5A, a photosensitive resin material 50 is applied to one surface of the crystal piece 11 by spin coating. Specifically, in the present embodiment, an epoxy resin having a function as an adhesive is applied in an adhesion process described later. Subsequently, exposure and development processes are performed. Specifically, as shown in FIG. 5B, a photomask M in which openings corresponding to the first resin pattern P1 constituting the resin core portion 24 are formed is used.

  By performing exposure processing and development processing using such a photomask M, a first resin pattern P <b> 1 is formed on the crystal piece 11 as shown in FIG. 5C.

  Thus, in this embodiment, since the resin pattern P1 is formed by the photolithography method, a fine pattern can be formed.

  Subsequently, as shown in FIG. 5D, the resin pattern P <b> 1 is heated and melted to form a semicircular resin core portion 24. Various methods can be exemplified as the heating method. In this embodiment, for example, the crystal unit 1 is placed in a heating furnace to perform the heat treatment.

  After forming the resin core portion 24 in this way, the excitation electrodes 12 and 13 are formed on the crystal piece 11. The excitation electrodes 12 and 13 are patterned into a desired shape after forming an Au / Cr layer by sputtering, for example. Specifically, the Au / Cr layer is patterned so that the resin core portion 24 is covered and the resin exposed portions 27 and 28 are exposed. Further, patterning is performed so that the undercut amount W of the Cr layer with respect to the Au layer is equal to or greater than the film thickness of the Cr layer during patterning of the Cr layer. Thereby, the conductive films 25 and 26 and the resin exposed portions 27 and 28 covering the excitation electrodes 12 and 13 and the resin core portion 24 can be formed. Through the above-described steps, the crystal unit 1 including the resin core portion 24 and the resin exposed portions 27 and 28 at the connection portions of the excitation electrodes 12 and 13 can be manufactured.

  Next, a method for mounting the crystal unit 1 will be described with reference to FIG. Here, FIG. 4 is a cross-sectional view showing the bump electrode 14 when the crystal unit 1 is mounted on the container 3. First, the bump electrode 14 provided on the crystal unit 1 is brought into contact with and pressed against the connection electrodes 33 and 34 formed on the container main body 31 (see FIGS. 4A and 4B). The crystal unit 1 is mounted while heating.

  At this time, the conductive films 25 and 26 including the undercut portions are deformed to follow the shapes of the connection electrodes 33 and 34, respectively. Then, it follows the surface shape of the resin exposed portion 27 and the connection electrode 33, and the resin exposed portion 28 follows the surface shape of the connection electrode 34. As a result, the conductive film 25 and the connection electrode 33 and the conductive film 26 and the connection electrode 34 are in conductive contact with each other with a sufficient contact area. The resin exposed portions 27 and 28 are in contact with the connection electrodes 33 and 34. Then, the resin exposed portions 27 and 28 are cured. Therefore, the resin exposed portions 27 and 28 can bond the connection electrodes 33 and 34 and maintain the contact state between the conductive film 25 and the connection electrode 33, the conductive film 26 and the connection electrode 34.

  As described above, the crystal unit 1 is mounted in the container body 31. Thereafter, the container body 31 and the lid body 32 are joined to seal the crystal unit 1. In this way, the crystal resonator package 2 is formed. At this time, since the resin core portion 24 is covered with the conductive films 25 and 26, the outgas generated from the resin core portion 24 is prevented from deteriorating the vibration characteristics of the crystal resonator 1 (crystal piece 11). Further, since the resin exposed portions 27 and 28 are surrounded by the bump electrode 14, the resin exposed portions 27 and 28 are in a sealed state as shown in FIG. 4B, and the outgas generated from the resin exposed portions 27 and 28 is generated by the crystal resonator 1. It is possible to prevent the vibration characteristics of the (crystal piece 11) from being lowered. According to the crystal resonator package 2 formed as described above, the reliability of the crystal resonator 1 is improved by preventing the deterioration of the characteristics of the crystal resonator 1 caused by the outgas generated from the resin material. Further, when an impact such as a drop impact is applied to the connection portion between the crystal resonator 1 and the container body 31, the resin core portion 24 is elastically deformed to absorb the impact.

  In addition, this invention is not limited to the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention. For example, in the above embodiment, the adhesive material 15 has a circular shape in plan view, but may be formed in a rectangular shape. In the present invention, the bump electrode 14 is formed on the crystal unit 1, but the bump electrode 14 may be formed on the container body 31.

  DESCRIPTION OF SYMBOLS 1 ... Crystal oscillator (electronic component), 2 ... Crystal oscillator package (electronic component mounting structure), 3 ... Container (base material), 4 ... Lid, 11 ... Crystal piece (functional piece), 12, 13 ... Excitation electrode, 14 ... bump electrode, 15 ... resin exposed portion, 24 ... resin core (resin protrusion), 25, 26 ... conductive film (coating film, conductive portion), 27, 28 ... resin exposed portion, 33, 34 ... connection electrode.

Claims (11)

An electronic component mounting structure in which an electronic component is mounted on a base material having a connection electrode,
The electronic component is
A functional piece having a predetermined function;
A resin protrusion including a resin exposed portion whose surface is covered by a coating film including a conductive portion electrically connected to the functional piece, and at least a portion of which is exposed from the coating film;
Have
The electronic component is mounted on the base material in a state where the coating film and the connection electrode are in conductive contact with each other and the base material and the resin exposed portion are in contact with each other. Component mounting structure.   2. The electronic component mounting structure according to claim 1, wherein the resin exposed portion faces a closed space surrounded by the coating film and the connection electrode.   The electronic component mounting structure according to claim 1, wherein the functional piece is a crystal piece.   The electronic component mounting structure according to claim 1, wherein the coating film includes at least two layers.   The mounting structure according to claim 4, wherein an undercut amount of a lower layer of the coating film with respect to an outermost layer of the coating film is equal to or greater than a film thickness of the lower layer of the coating film.   The electronic component mounting structure according to any one of claims 1 to 5, wherein the coating film is configured by an electrode layer provided on the functional piece. An electronic component mounting structure in which an electronic component is mounted on a base material having a connection electrode,
The electronic component is
A functional piece having a predetermined function;
Having an electrode portion electrically connected to the functional piece;
The substrate is
A resin protrusion including a resin exposed portion, the surface of which is covered with a coating film including a conductive portion electrically connected to the connection electrode, and at least a part of which is exposed from the coating film;
Have
The electronic component is mounted on the base material in a state where the coating film is in conductive contact with the electrode portion and the resin exposed portion is in contact with a part of the functional piece. Implementation structure.   The electronic component mounting structure according to claim 7, wherein the resin exposed portion is surrounded by the coating film and the electrode portion to form a closed space with the outside.   9. The electronic component mounting structure according to claim 7, wherein the functional piece is a crystal piece.   The electronic component mounting structure according to claim 7, wherein the coating film includes at least two layers.   The mounting structure for an electronic component according to claim 10, wherein an undercut amount of the lower layer of the coating film is equal to or greater than a film thickness of the lower layer of the coating film.

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