Base for electronic component packages, electronic component packages

Abstract

To improve reliability of mounting joint between an electronic component package and a circuit board by preventing cracks of electric conductive joint material such as solder.SOLUTION: An electronic component package has an external terminal 12 formed on a base 1 for holding an electronic component element 3. The external terminal 12 includes a main surface terminal 13 formed on a bottom surface of the base and side surface terminals 14, 15 formed on side surfaces of the base. The main surface terminal 13 and the side surface terminals 14, 15 are formed so as to connect with each other at the bottom surface and the side surface of the base. The side surface terminals 14, 15 are formed at positions outside the width of the main surface terminal 13.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a base for an electronic component package used in electronic devices and the like, and to an electronic component package. [Background technology]

[0002] Examples of electronic components that require hermetic sealing include piezoelectric vibration devices such as quartz crystal units, quartz crystal filters, and quartz crystal oscillators. In each of these products, a metal thin film electrode is formed on the surface of the quartz crystal plate, and the quartz crystal plate (specifically the metal thin film electrode) is hermetically sealed to protect the metal thin film electrode from the outside air.

[0003] Due to the demand for surface mounting of components, these piezoelectric vibration devices are increasingly being housed airtight in a package made of insulating material such as ceramic. For example, Patent Document 1 discloses a configuration in which a package made of a ceramic material with a base (mounting substrate) having a mounting portion for a quartz vibration plate and a lid (cover) with an inverted concave cross section hermetically sealed between them is mounted on a circuit board and bonded via a conductive bonding material such as solder.

[0004] In this conventional piezoelectric vibration device, a terminal electrode is formed on the bottom surface of the base, and the terminal electrode extends from the bottom surface of the base to the side surface through castellations formed on the side surface of the base in order to check the connection state by creeping up of solder (conductive bonding material).

[0005] Meanwhile, for circuit boards on which conventional piezoelectric vibration devices are mounted, so-called glass epoxy boards, in which mesh-like glass fibers are impregnated with epoxy resin, are widely used because of their ease of processing and cost advantages. Solder paste is applied to the upper part of the electrode pattern of the circuit board by a method such as screen printing. The terminal electrodes of the package of the piezoelectric vibration device are then placed on the electrode pattern of the circuit board in a state of being superimposed thereon, and the solder paste is melted in a melting furnace (heating furnace, etc.) to solder the piezoelectric vibration device onto the circuit board. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2002-76813 Summary of the Invention [Problem to be solved by the invention]

[0007] However, due to the difference in thermal expansion coefficient between the package and the circuit board, stress is generated in the conductive bonding material such as solder that bonds the package and the circuit board, which may cause cracks.

[0008] In particular, when a combination configuration using a ceramic material such as alumina as the package and a glass epoxy board as the circuit board is used for applications in harsh environments such as in-vehicle use, the package and circuit board are used in high and low temperature environments, and the difference in thermal expansion coefficient between the package and the circuit board makes it easy for fatigue failure to occur in the conductive bonding material such as solder.

[0009] In this way, the problem of cracks in conductive bonding materials such as solder, which was not a significant issue in normal temperature environments, became prominent in high and low temperature environments, and there was also the problem that peeling occurred at the cracked parts of the conductive bonding material such as solder when the package and the circuit board were subjected to an impact.

[0010] The present invention has been made to solve the above-mentioned problems, and has as its object to provide a base for an electronic component package and an electronic component package that prevent cracks in conductive bonding materials such as solder and improve the reliability of the mounting and bonding between the electronic component package and a circuit board. [Means for solving the problem]

[0011] The present invention provides a base for an electronic component package in which at least four external terminals are formed on an insulating substrate that is rectangular in plan view and holds an electronic component element, the external terminals having a main surface terminal portion formed on a bottom surface of the base and a side surface terminal portion formed on a side surface of the base, the main surface terminal portion and the side surface terminal portion are formed to be connected to each other at the bottom surface and side surface of the base, and the side surface terminal portions are formed at positions outside and inside both ends of the width of the main surface terminal portion. The side terminal portions are formed by dividing the main surface terminal portion into two portions, and the side terminal portions on the four corner sides of the insulating substrate have different widths from the side terminal portions on the central side. is.

[0012] With the above configuration, the main surface terminal portion, which faces the mounting electrode of the circuit board and has a relatively large bonding area using a conductive bonding material such as solder, thereby enhancing the electrical connection function, and the side surface terminal portion, which is arranged in a direction perpendicular to the mounting electrode of the circuit board and creates an anchor effect using a conductive bonding material such as solder, thereby enhancing the mechanical bonding strength with the circuit board, can coexist in a single external terminal while each portion shares its specialized functions.

[0013] Furthermore, when forming a single external terminal, the side terminal portion is formed at a position outside the width of the main surface terminal portion, so that even if stress is generated in the conductive bonding material such as solder that joins the base and the circuit board due to the difference in thermal expansion coefficients between them, the stress can be received by the side terminal portion before being transmitted directly to the main surface terminal portion, and the stress can be transmitted to the main surface terminal portion in a reduced state.

[0014] As a result, cracks due to stress are less likely to occur in the conductive bonding material such as solder of the main surface terminal portion, and the electrical and mechanical connection function of the external terminal as a whole can be ensured in a more stable state. Furthermore, even if cracks occur in the conductive bonding material such as solder in the side terminal portion, the occurrence of cracks in the conductive bonding material such as solder in the main surface terminal portion can be delayed.

[0015] In particular, in a configuration in which four or more external terminals are formed on the bottom surface of the base, there is a concern that the area occupied by each external terminal in the bottom surface area of ​​the base will become smaller as the electronic component becomes smaller. However, in the present invention, the mechanical joint strength can be increased by distinctively arranging the side terminal portions relative to the main surface terminal portions without unnecessarily increasing the area occupied by each external terminal in response to the miniaturization of the electronic component.

[0016] In addition to the above configuration, the side terminal portion may be divided and formed on both ends of the width of the main surface terminal portion. In addition to the above-mentioned effects, in this configuration, even if stress occurs in a conductive bonding material such as solder that bonds the base and the circuit board due to a difference in thermal expansion coefficient between them, the stress can be alleviated in an area between the side terminal portions where no side terminal portion exists. Also, the side terminal portions at the four corners of the insulating board may have different widths from the side terminal portion at the center. In addition to the above-mentioned effects, in this configuration, by combining at least two or more side terminal portions with different widths with the main surface terminal portion, the balance of stress applied to the side terminal portion can be changed to prevent local concentration of stress.

[0017] In addition to the above configuration, the above 4 Corner side In addition to the above-mentioned advantageous effects, the side terminal portion on the central side may be formed wider than the side terminal portion on the central side. 4 Even if a crack occurs in the conductive bonding material such as solder at the side terminal portion on the corner side, it can be held more firmly at the side terminal portion on the central side, thereby suppressing the progression of the crack in the conductive bonding material such as solder at the main surface terminal portion.

[0018] In addition to the above configuration, the above 4 Corner side The side terminal portions may be formed in the four corner regions of the base. In addition to the above-mentioned advantageous effects, this configuration provides the external terminals with a stronger hold and suppresses the progression of cracks in the conductive bonding material such as solder by forming the side terminal portions in the four corners that are the starting points of stress.

[0019] In addition to the above configuration, the main surface terminals may be formed along opposing long sides of the bottom surface of the base. In this configuration, in addition to the above-mentioned advantageous effects, by arranging the main surface terminals along the long side direction of the base where the thermal expansion difference between the base and the circuit board is relatively large and which is susceptible to the effects of stress, the side terminals are also arranged in the long side direction corresponding to the main surface terminals, so that the external terminals can be held more firmly and the progression of cracks in the conductive bonding material such as solder can be suppressed.

[0020] The present invention may also provide an electronic component package having a lid for hermetically sealing the electronic component element in the base of the electronic component package described above. With this configuration, it is possible to provide an electronic component package that can achieve the above-mentioned effects. Effect of the Invention

[0021] According to the present invention, it is possible to provide a base for an electronic component package, and an electronic component package, which prevents cracks in a conductive bonding material such as solder and improves the reliability of mounting and bonding between the electronic component package and a circuit board. [Brief description of the drawings]

[0022] [Figure 1] FIG. 2 is a bottom view of the surface mount type crystal resonator according to the embodiment of the present invention. [Diagram 2] A cross-sectional view of the surface mount crystal unit in Figure 1 mounted on a circuit board along line AA. [Diagram 3] A cross-sectional view of the surface mount crystal unit in Figure 1 mounted on a circuit board along line BB. [Figure 4] FIG. 13 is a bottom view of a surface mount crystal resonator showing a modified example of an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In each of the following embodiments, the present invention is applied to a surface mount crystal resonator as an electronic component package.

[0024] As shown in Figures 1, 2 and 3, a surface mount crystal resonator according to an embodiment of the present invention comprises a crystal vibration plate 3 which is an electronic component element, a base 1 (insulating substrate) which has a recess with an open top and which holds (houses) the crystal vibration plate 3, and a lid 2 which is joined to the opening of the base 1 to hermetically seal the crystal vibration plate 3 held by the base 1.

[0025] The base 1 is generally a rectangular parallelepiped, and is constructed by appropriately laminating conductive materials such as tungsten, molybdenum, etc., on a ceramic insulating substrate such as alumina, etc. As shown in Fig. 2, the base 1 has a storage section 10 that is concave in cross section, and a bank section 11 that is provided around the storage section 10 so as to surround it.

[0026] Specifically, the base 1 is composed of a ceramic base substrate 1a in the shape of a rectangular plate (rectangular in plan view) and a ceramic frame 1b with a large central hole and an outer size (outer size in plan view) approximately equal to that of the base substrate 1a, and the base substrate 1a, frame 1b, and part of the sealing member 11a are fired integrally. The upper surface of the bank portion 11 (frame 1b) is flat, and the sealing member 11a (sealing material, metal layer, etc.) is formed on the bank portion 11. The number of layers of the frame in the base 1 may be two or more depending on the package configuration.

[0027] In this embodiment, since a sealing configuration using, for example, a gold-tin brazing material is used as an example, a configuration is shown in which a nickel-plated layer and a gold-plated layer are formed on the upper surface of a metallized layer made of tungsten, molybdenum, etc. as the sealing member 11a. However, depending on the sealing configuration, a configuration in which a metal ring is formed on the top of each of these layers, or a configuration in which glass is formed may be shown.

[0028] Castellations C1 are formed vertically from the bottom surface of the base to the top surface (upper surface) on the four corners (four corners) of the periphery (peripheral edge in plan view) of the base 1 on the side surfaces of the base 1 at the four corners. In addition, two castellations C2 are formed vertically from the bottom surface of the base to the top surface (upper surface) on two specific side surfaces S1, S3 connected to long sides H1, H3 as opposing specific sides of the bottom surface of the base 1 on the periphery (peripheral edge in plan view) of the base 1.

[0029] The castellation C2 on the central side of the particular side of the base 1 is formed to be wider than the castellation C1 on the corner side of the particular side of the base 1, for example, to be about two to five times as wide.

[0030] The bottom surface of the base 1 (the back surface of the base 1) is rectangular in plan view, and is provided with four external terminals 12. Each external terminal 12 has a main surface terminal portion 13 formed on the bottom surface of the base 1, and side surface terminal portions 14, 15 formed inside castellations on the side surfaces of the base 1.

[0031] The main surface terminal portion 13 has two main surface terminal portions formed in a rectangular shape in a plan view along opposing long sides H1, H3 of the bottom surface of the base 1. The side surface terminal portion 14 is formed inside a castellation C1 formed on the side surface at each of the four corners of the base 1. The side surface terminal portion 15 is formed inside a castellation C2 formed on specific side surfaces S1, S3 of the base 1. Each main surface terminal portion 13 and each side surface terminal portion 14, and each main surface terminal portion 13 and each side surface terminal portion 15 are formed and connected to each other at the bottom surface and side surface of the base 1.

[0032] In this embodiment, as described above, the castellations C1 and C2 are formed with different width dimensions, and therefore the width dimension W1 of the side terminal portion 14 on the corner side and the width dimension W2 of the side terminal portion 15 on the central side formed here are also formed to be different, and in particular, the side terminal portion 15 on the central side is formed to be wider than the side terminal portion 14 on the corner side.

[0033] For example, when the width dimension W1 of the side terminal portion 14 at the corner of the long side is 0.05 mm, the width dimension W2 of the side terminal portion 15 at the center of the long side is formed to be about 0.1 mm, which is twice as large, to 0.4 mm, which is eight times as large. Note that the width dimension W2 of the side terminal portion 15 at the center of the long side is desirably formed to be about 1 / 6 to 1 / 3 of the width dimension W3 in the long side direction of the base 1 in order to suppress interference with other wiring of the base and improve the bonding strength with the circuit board 4 described later. Moreover, the specific width dimension W2 of the side terminal portion 15 is desirably formed to be 0.25 mm or more, which is desirable from the viewpoint of improving the bonding strength, since the solder fillet has a stronger structure.

[0034] In the present invention, a feature lies in the positional relationship between each main surface terminal portion and each side surface terminal portion on the bottom surface of the base 1, and each side surface terminal portion 14, 15 is formed in a state where it is positioned outward from the positions of both ends 131, 132 along each long side (H1, H3) of each main surface terminal portion 13. That is, in the two main surface terminal portions 13 formed along the long side H1, a castellation C1 and a side surface terminal portion 14 formed therein are formed at both ends of the long side H1 located outward from the outer end 131 of each main surface terminal portion 13, and a castellation C2 and a side surface terminal portion 15 formed therein are formed at a position closer to the center of the long side H1 located inward from the inner end 132 of each main surface terminal portion 13.

[0035] Similarly, in the two main surface terminal portions 13 formed along the long side H3, castellations C1 and side terminal portions 14 formed therein are formed at both ends of the long side H3 located outside the outer end portion 131 of each main surface terminal portion 13, and castellations C2 and side terminal portions 15 formed therein are formed at a position closer to the center of the long side H3 located inside the inner end portion 132 of each main surface terminal portion 13. As a result, the width along the long sides (H1, H3) of each main surface terminal portion 13 (both ends in the long side direction in this embodiment) is also divided into two side terminal portions 14, 15 and formed at outer positions.

[0036] Each external terminal 12 extends to and is electrically connected to an electrode pad 16 formed on the inside bottom surface of the base 1 via a side terminal portion 14, a side terminal portion 15 formed on the castellation C1 or the castellation C2, or a via hole not shown.

[0037] These external terminals 12 (main surface terminal portion 13, side surface terminal portion 14, and side surface terminal portion 15) and electrode pads 16 are configured in the same manner as the sealing member 11a by forming metallization by integrally firing a metallization material such as tungsten or molybdenum with the base 1, forming nickel plating on top of that, and then forming gold plating on top of that.

[0038] A quartz crystal vibrating plate 3 (an electronic component element in the present invention) is mounted on the electrode pad 16. A pair of excitation electrodes and extraction electrodes (not shown) are formed on the front and back surfaces of the quartz crystal vibrating plate 3. The pair of excitation electrodes and extraction electrodes are formed, for example, in contact with the quartz crystal vibrating plate 3 (from above the quartz crystal vibrating plate 3) by laminating chromium and gold in that order, chromium, gold and chromium in that order, chromium, silver and chromium in that order, or chromium and silver in that order. Each of these electrodes (the pair of excitation electrodes and extraction electrodes) can be formed by a thin film formation method such as a vacuum deposition method or a sputtering method.

[0039] The extraction electrodes of the quartz crystal vibration plate 3 are conductively bonded to the electrode pads 16 by a conductive bonding material (not shown), and the quartz crystal vibration plate 3 is held on the base 1. For example, conductive bonding between the excitation electrodes of the quartz crystal vibration plate 3 and the electrode pads 16 of the base 1 can be achieved by using conductive bonding materials such as a conductive resin adhesive, metal bumps, metal-plated bumps, or brazing material.

[0040] The lid 2 that hermetically seals the base 1 is made of a plate-shaped metal material with a sealing member 11a such as a gold-tin brazing material formed thereon. The outer shape of the lid 2 in a plan view is substantially the same as or slightly smaller than the outer shape of the base 1. The material of the lid 2 is not limited to a metal material, and may be a ceramic material or a glass material.

[0041] The crystal plate 3 is stored in the storage section 10 of the base 1, covered with the lid 2, and hermetically sealed by a method such as fusion bonding in a heating furnace, completing a surface mount crystal unit (package for electronic components). Note that the method of hermetically sealing the base 1 and the lid 2 is not limited to soldering, and other methods such as welding and fusion bonding can be used depending on the various materials (base, lid, sealing material, etc.).

[0042] As shown in Figs. 2 and 3, the completed crystal unit is bonded to the upper part of an electrode pattern 41 of a circuit board 4 made of a glass epoxy material via a conductive bonding material D such as solder.

[0043] In the above embodiment, two side terminal portions 14 and 15 are arranged at both ends of the width direction of the main surface terminal portion 13 of each external terminal 12. However, the side terminal portions may be arranged at other than both ends and divided into three or more portions in total.

[0044] Furthermore, as shown in FIG. 4, a castellation C3 may be formed in each external terminal 12 so that its width dimension W4 is larger than the positions (both ends in the width direction) of both ends 131, 132 along each long side (H1, H3) of each main surface terminal portion 13, and a side surface terminal portion 17 may be formed along this castellation C3, thereby forming a side surface terminal portion 17 that is larger in width than both ends in the width direction of the main surface terminal portion 13 and that protrudes to a position outside in the width direction.

[0045] With the above-described configuration, it is possible to further reduce and prevent the adverse effects of cracks in conductive bonding materials such as solder due to thermal shock stress, and it is possible to provide an inexpensive electronic component package base and electronic component package that improve the reliability of mounting and bonding to a circuit board.

[0046] In the above embodiment, the external terminals and the castellations C2 (side terminal portions) are arranged on the long sides (H1, H3) as the specific opposing sides, but they may be arranged on the short sides (H2, H4), or may be formed in the directions of both the long sides (H1, H3) and the short sides (H2, H4). Also, the castellations C1 at the four corners of the base may not have side terminal portions. In this case, a plurality of castellations C2 and side terminal portions may be formed on a specific side, either the long sides (H1, H3) or the short sides (H2, H4), or a plurality of castellations C2 and side terminal portions may be formed on both the long sides (H1, H3) and the short sides (H2, H4).

[0047] In the above embodiment, a surface mount type crystal resonator is taken as an example, but the present invention can also be applied to other surface mount type electronic component packages used in electronic devices such as crystal filters and crystal oscillators. In addition, although a ceramic material is disclosed as the insulating package (base), a glass material or crystal may be used. Although metallization is disclosed as the metal film of the terminal electrodes, a plated material may also be used. Although the number of terminal electrodes is four, the present invention can also be applied to those with five or more terminals.

[0048] The present invention can be implemented in various other ways without departing from its spirit or main features, and should not be interpreted as being limited. The scope of the present invention is indicated by the claims and is not limited to the text of the specification. Furthermore, all modifications and changes within the scope of the claims are within the scope of the present invention. [Industrial Applicability]

[0049] The present invention can be applied to packages for electronic components such as crystal resonators, and bases for electronic component packages. [Explanation of symbols]

[0050] 1 Base 2 lid 3. Quartz crystal plate (electronic component element) 4 Circuit Board

Claims

1. A base for an electronic component package, the base having at least four external terminals formed on an insulating substrate having a rectangular shape in a plan view and holding an electronic component element, the external terminal has a main surface terminal portion formed on a bottom surface of the base and a side surface terminal portion formed on a side surface of the base, the main surface terminal portion and the side surface terminal portion are formed to be connected to each other at the bottom surface and the side surface of the base, the side terminal portions are formed at positions outside and inside both ends of the width of the main surface terminal portion, The side terminal portions are formed by dividing the width of the main surface terminal portion, and the side terminal portions on the four corner sides of the insulating substrate have different widths from the side terminal portion on the central side. A base for an electronic component package.

2. 2. A base for an electronic component package according to claim 1, The side terminals on the central side are formed wider than the side terminals on the four corners. A base for an electronic component package.

3. 3. A base for an electronic component package according to claim 2, The side terminals on the four corners are formed in the four corner regions of the insulating substrate. A base for an electronic component package.

4. 4. An electronic component package comprising: a base for an electronic component package according to claim 1; and a lid for hermetically sealing said electronic component element.

Images