JPH1075074A - Electronic part using mid package - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic part using an MID (substrate molded of resin) package where the length of the conductor part from an element to a printed board to mount an electronic part can be shortened, whereby the effects on the property of the element by this conductor part is reduced, and also the airtightness is improved and moreover the package becomes advantageous with respect to cost reduction and downsizing, also. SOLUTION: An MID package is constituted of an MID case 1 which has a recess 7 of two-stage structure with its topside open, and a cover 6 which blocks the topside opening of the MID case 1. A lead electrode 2 is made at the inner face of the recess 7, and at the bottom of the recess 7 an element 4 is fixed, being electrically connected with the lead electrode 2. The lead electrode 2 and a terminal 3 for substrate connection made at the bottom of the case 1 are connected with each other by the through-hole 9, provided spreading over the bottom of the case 1 from the middle stage b of the recess 7. An adhesive 5 is filled between the cover 6 and the element 4 within the recess 7. Moreover, the through-hole 9 is blocked with the adhesive 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic component comprising a case made of MID (resin molded substrate) and housing an element requiring hermetic sealing such as a surface acoustic wave filter (SAW filter). .

[0002]

2. Description of the Related Art A SAW filter is an element utilizing surface acoustic waves, and cannot form a protective film or the like on an electrode forming surface. In addition, since it is weak to moisture, it must be housed in a hermetically sealed case. As a conventional example of such a sealing structure, as shown in FIG. 6A, a device 51 is housed in a ceramic case 50, and a conductor 52 formed in the case 50 and a pad of the device 51 are bonded to a bonding wire 53. And a metal lid 54 joined by a hermetic seal 55. In this structure, the case 50 is integrated by stacking and firing three materials 50a, 50b, and 50c, and the conductor 52 connecting the elements 51 is formed on the upper surface of the second-stage case material 50b. Is connected to the electrode 56. The element 51 is configured such that the electrode 56 on the side surface of the case 50 is
Are electrically connected and fixed by solder 59.

On the other hand, Japanese Patent Application Laid-Open No. 6-132673 discloses an example in which an element is formed by using an MID package as shown in FIG. A recess 62 having a two-stage structure is formed on the upper surface,
An element 63 is provided on the bottom thereof, and a bonding wire 65 is provided on a lead electrode 64 formed from the recess 62 to the upper surface of the case.
And a recess 6
The lid 66 is fitted above the intermediate step 62a of
7 and the like, and a surface mounting structure is realized by using the upper surface as a mounting surface on a substrate.

[0004]

According to the structure shown in FIG. 6A, the case 50 is made of ceramic, and these must be stacked and fired to produce the case 50. Since the lid 54 must be joined, equipment and material costs are required, and man-hours and
There is a problem that it takes time and costs increase.

In order to solve such a problem of high cost, it is conceivable to constitute an electronic component by an MID package as shown in FIG. 6B disclosed in Japanese Patent Application Laid-Open No. 6-132672. However, in the structure of FIG. 6B, since the electrode 68 for soldering to the printed board is on the insertion side of the element 63, if the management of the adhesive 67 is poor, the connection surface with the printed board floats. This may result in mounting failure. Further, if the amount of the adhesive is reduced to solve such a problem, the airtightness is reduced.

Since the element 63 is bonded by wire bonding, the electrode surface 63a of the element 63 is
Of the adhesive 67 (opening side of the concave portion 62).
In some cases, the liquid may flow down to the electrode surface of the element 63, which may degrade the characteristics of the element. The problem of the mounting failure and the flow of the adhesive into the electrode surface of the element 63 may occur even if the adhesive 67 is cured by reversing the vertical direction of the case 61 or the curing method is changed. That is.

Further, when the adhesive 67 is cured, the expansion of the air causes the adhesive 67 to become air bubbles, and if the air bubbles are repelled, they may adhere to the surface of the case electrode 68 and cause a mounting failure. Further, since the lid 66 is configured to be fitted into the concave portion 62 and bonded, there is a problem that a large number of pieces cannot be formed, productivity is low, and cost is increased.

For example, as shown in FIG. 6 (C), a large number of lids are bonded to the surface of the electrode 68 and soldered to the side or bottom surface of the case 61 to the substrate, as shown in FIG. If the electrode 69 is pulled out, the electrodes 68, 69
Portion becomes longer, the inductance component increases, and the characteristics of the element 63 deteriorate.

SUMMARY OF THE INVENTION In view of the above problems, the present invention eliminates problems such as an adhesive for adhering a lid, sagging on a printed circuit board and an element electrode surface, and reduces the length of a connecting conductor portion from an element to a printed circuit board. It is an object of the present invention to provide an electronic component using an MID package, which can be shortened, thereby reducing the influence of the connection conductor portion on the characteristics of the element, and being advantageous in terms of airtightness and cost.

[0010]

According to the present invention, a lead electrode is formed on the inner surface of the recess, and an element is fixed to the bottom of the recess by being electrically connected to the lead electrode. Connecting the lead electrode and the substrate connection terminal portion formed on the bottom surface of the case by a through hole provided from the middle step portion of the concave portion to the bottom surface of the case;
An adhesive is filled between the lid and the element in the recess, and at least a part of the through hole is filled with the adhesive to close the through hole.

[0011]

In the present invention, since the electrode surface of the element faces the bottom of the concave portion of the case and is electrically connected, there is no danger of the adhesive for stopping the lid on the electrode surface of the element. Further, since the opposite side of the opening surface of the concave portion is the mounting surface for the printed board, the lid can be formed into a multi-piece structure, and the bonding can be performed with the opening face side down, and the connection conductor portion ( The electrode is not likely to be covered by the adhesive.

Further, as shown in FIG. 6C, the conductor for connection to the printed circuit board is not routed from the upper surface (opening surface of the concave portion) to the side surface of the case, and the through portion is formed from the intermediate step portion of the concave portion. Since it is drawn out to the lower surface of the case through the hole, the length of the connection conductor portion to the printed board is shortened, and the deterioration of the characteristics of the element can be reduced.

Further, since the through hole is closed by the adhesive and the space between the element and the lid is filled with the layered adhesive, airtightness is ensured.

[0014]

1 is a longitudinal sectional view showing an embodiment of the present invention, FIG. 2A is a plan view of a case 1 of the embodiment, FIG. 2B is an exploded side view, and FIG. FIG. 3A is a plan view showing a state in which a lead electrode 2 is formed on a case 1, and FIG. 3B is a view showing a printed circuit board connecting terminal portion 3 on the bottom surface of the case 1.

As shown in FIG. 2 (B), the electronic component of this embodiment includes an MID case 1 and an element 4 such as a SAW filter.
Before the electronic components are assembled, the adhesive 5 includes a pellet-shaped adhesive 5 and a lid 6. The case 1 has a concave portion 7 having an upper surface opening,
The concave portion 7 has a two-stage structure including a bottom surface a and an intermediate step portion b. An inclined surface d is formed on two opposing surfaces between the intermediate step portion b, the upper surface c, and the bottom surface a. I have.

As shown by hatching in FIG. 3A, a lead electrode 2 made of gold is formed on the inner surface of the recess 7.
The element 4 is a flip chip having a comb-shaped electrode formed on the lower surface. The element 4 is electrically connected to the lead electrode 2 by ultrasonic waves while the case 1 is heated while the case 1 is heated. Fixed.

The lead electrode 2 (shown by oblique lines in FIG. 3A) and a substrate connection terminal 3 formed on the bottom of the case 1
(Shown by oblique lines in FIG. 3B) is a through hole 9 provided from the intermediate step b of the recess 7 to the bottom surface of the case.
Connected by 9a denotes a conductor plated on the inner wall of the through hole 9. An adhesive 5 is filled between the lid 6 and the element 4 in the recess 7, and the adhesive 5 closes at least a part of the through hole 9. On the side surface of the case 1, a surface having a semicircular horizontal cross-sectional shape is provided.
A side electrode 10 connected to the substrate connection terminal 3 is formed.

FIG. 4 is a view showing a manufacturing process after manufacturing the electronic component case 1. First, as shown in FIG.
The adhesive 5 in the form of a pellet is fitted on the element 4 fixed in the recess 7, and then, as shown in FIG. As shown in FIG. 4 (C), pressure is applied from the upper and lower surfaces, and as shown in FIG. 4 (D), the adhesive 5 is melted and cured so as not to enter the through holes 9 by inverting and heating. As a result, the adhesive 5 temporarily in a fluid state is filled in at least a part of the through-hole 9 to close it, and
The lid 6 is adhered with the adhesive 5, the gap between the element 4 and the lid 6 is covered with the adhesive 5, and the element 4 and the outside air are shut off with the adhesive 5.

As shown in FIG. 2B, the bottom a
A, the height difference from the middle step b to the upper surface c is B, the thickness including the bumps 4a of the element 4 is C, and the thickness of the pellet-shaped adhesive 5 before melting is A. In the case of D, the adhesive 5 is pressed as shown in FIG. 4C by setting A ≧ C and D ≧ B (preferably, dimensions are set so that a magnitude relation in which D is slightly larger than B is established). In this case, the adhesive 4 can be filled in the through hole 9 without exerting an excessive force on the element 4.

The electronic component thus manufactured is shown in FIG.
As shown in FIG.
Are electrically connected and fixed. As described above, the electronic component of the present invention has a through hole 9 from the intermediate step b of the recess 7 to the bottom surface opposite to the opening side of the case 1.
Therefore, the length of the portion functioning as the connection conductor is shortened as compared with the structure of FIG. 6C, and the influence on the characteristics of the element is reduced. When the structure of the present embodiment was adopted, the length of the circuit from the bump 4a to the lower end of the through hole 9 could be reduced to 1.6 mm.

If a through hole can be provided from the bottom surface of the concave portion 7 to the lower surface of the case 1, the length of the connecting conductor portion to the printed board can be further reduced. Then, adhesion of the lid 6 and sealing of the through hole cannot be performed at the same time. If the through hole is previously filled with a resin or solder, the element 4 may be contaminated and the mounting surface may float. . Further, the through hole cannot be closed only by the gold bump due to the problem of airtightness. If the through hole 9 is provided from the intermediate step portion b to the lower surface of the case 1 as in the present invention, such a problem can be solved.

As described above, in the structure of the present invention,
Since the length of the circuit from the substrate 15 to the element 4 can be reduced, in the SAW filter, as shown in the frequency characteristic diagram of FIG. 5, the characteristics as a filter can be improved.

Since the through hole 9 is closed by the adhesive 5 and the space between the element 4 and the lid 6 is filled with the layered adhesive 5 which is temporarily molten, the structure shown in FIG. As shown in (C), the periphery of the lid 66 is
Thus, compared to the case of bonding, there is no problem of lowering the airtightness due to unevenness of the adhesive and the airtightness is improved. In addition, since it is not necessary to provide a connection terminal portion on the upper surface, which is the opening side of the case, the case 1 needs to have a sufficient width for the connection terminal portion.
There is no need to increase the size.

When an electronic component is formed using an MID package as in the present invention, the case 1 and the lid 6 must be adhered to each other with an adhesive 5 having high adhesion.
In the embodiment, as the material of the case 1, LCP (liquid crystal polymer), epoxy resin (Effect of Toshiba Chemical Corporation, E
PH), BT resin,
An epoxy resin (EP-H, manufactured by Toshiba Chemical Co., Ltd.) with copper plating + nickel plating + gold plating applied to its surface is used in combination with a pressure cooker test (test conditions, 121 ° C., 2 atm, humidity) 100
%) And put into a Fluorinert solution at 125 ° C. to perform a bubble leak test to determine whether or not air bubbles appear.
In the case of (1), a leak was observed in about 48 hours, but in the case of the epoxy resin, no leak was observed even after 96 hours. Therefore, it is preferable to use an epoxy resin for the case 1.

When the element 4 made of a LiNbO ₃ -based element is formed, a conventional ceramic case shown in FIG. 6A using a typical alumina case, an epoxy resin and an LCP are used. In comparison with the case, the thermal expansion coefficients are as follows: LiNbO ₃ : 1.3 × 10 ⁻⁵ , alumina: 0.7 × 1
0 ^-5 epoxy resin: 1.5 × 10 ^-5 , LCP: 2 to 5 × 10
^-5 , and in the sense that the joint between the element and the case is not destroyed by thermal shock, it is better to use an epoxy resin that has a similar coefficient of thermal expansion to that of the element body of the element 4, and to use a ceramic. It is more advantageous than that.

[0026]

According to the present invention, since the connection conductor is drawn out through the through hole from the middle of the concave portion of the case to the bottom surface opposite to the opening side, the length of the connection conductor is reduced, and The effect on characteristics is reduced, and good characteristics are obtained. Since the device is mounted in the recess with the device electrode surface facing the bottom of the recess, there is no problem such as dripping of the adhesive on the device electrode surface. Since the mounting surface is used, it is possible to prevent the adhesive on the lid from affecting the mounting surface. In addition, since it has a MID structure,
It can be provided at a low price. Further, since the through holes are closed by the adhesive and the adhesive is filled between the element and the lid, the airtightness is improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of an electronic component according to the present invention.

FIG. 2A is a plan view of a case according to the present embodiment, and FIG. 2B is an exploded side view of parts before assembly.

FIG. 3A is a plan view showing a state in which lead electrodes are formed on a case in the present embodiment, and FIG. 3B is a diagram showing a printed circuit board connection terminal portion on the bottom surface of the case.

FIGS. 4A to 4D are process diagrams of the present embodiment.

FIG. 5 is a frequency characteristic comparison diagram of the present embodiment and a conventional example.

6A and 6B are longitudinal sectional views of a conventional hermetically sealed electronic component.

[Explanation of symbols]

1: Case, 2: Lead electrode, 3: Terminal part for board connection,
4: element, 5: adhesive, 6: lid, 7: recess, 9: through hole, 10: side electrode, 15: printed board, 16: pad, 17: solder, a: bottom, b: middle step

[Procedure amendment]

[Submission date] October 30, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Fig. 6

[Correction method] Change

[Correction contents]

6 (A), (B), (C) is a longitudinal sectional view of a conventional hermetically sealed parts, respectively.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Shuichiro Yamamoto 1-13-1 Nihonbashi, Chuo-ku, Tokyo Inside TDK Corporation

Claims (1)

[Claims] 1. An MID having a recess having a two-stage structure with an upper surface opening.
A case and a lid for closing an upper opening of the MID case constitute a MID package, a lead electrode is formed on the inner surface of the recess, and an element is fixed to the bottom of the recess by being electrically connected to the lead electrode. Connecting the lead electrode and a substrate connection terminal formed on the bottom surface of the case by a through hole provided from an intermediate step of the recess to the bottom surface of the case; An electronic component using an MID package, wherein an adhesive is filled in between, and at least a part of the through hole is filled with the adhesive to close the through hole.