JPS60249410A - Attaching method of resonator - Google Patents

Abstract

PURPOSE:To make posts unnecessary, to reduce the cost and to improve the yield by fusing and solidifying a solder on a solder adhesive material layer on a supporting base body to form solder projections and sticking a resonator to these projections with a binder. CONSTITUTION:Thick film conductors 17 are provided on an insulating circuit board 16, and plane circular conductor parts 17a are provided on them. Colored glass layers 19b are formed on narrow conductors 17b connected to circular conductors 17a, and simultaneously, colored glass layers 19a as positioning patterns are formed. A solder flux 25 is applied onto circular conductors 17a, and solder balls 26 are supplied onto them. Solder balls 26 are solidified by cooling after fusing to form semispherical solder projections 20 and 21. A conductive adhesive is applied onto solder projections 20 and 21, and a crystal resonator 11 is placed on solder projections 20 and 21.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for attaching a vibrator such as a crystal to a substrate, which is used when obtaining a reference frequency signal in a thick film integrated circuit.

Conventional technology When incorporating a crystal oscillator to obtain the reference frequency of an electronic circuit in a thick film integrated circuit, the crystal oscillator incorporated in the crystal oscillator is supported directly on the circuit board in order to reduce the size.・There was a request to fix it.

FIG. 9 shows a structure adopted to meet this requirement. In the drawing, (1) is a circuit board, (2) is a thick film conductor, and (3) is a cylindrical post (metallic support).
, (4) is a disk-shaped crystal resonator, (5) is an electrode of the crystal resonator, (6) (71 is solder, and (8) is a conductor.

Problems to be Solved by the Invention It has been found that this structure has the following drawbacks.

■ The cost of post (3) is high. i.e. post (3)
If it is a relatively low-cost punched product, as shown in Figure 10, peripheral sag (9) will occur at the bottom of the post (3), and solder (6) will creep up on the side of the post (3). As the amount of solder (6) between the post (3) and the thick film conductor (2) decreases, the amount of solder (6) between the post (3) and the thick film conductor (2) increases, making it easy for the post (3) to tilt. As shown in FIG.
) is no longer automatically adjusted to the center of the
Misalignment of the post (3) occurs. If the inclination or misalignment of the posts (3) is large, the spacing between the posts may be too narrow and the crystal oscillator (4) will not fit within the spacing between the posts, or conversely, the spacing between the posts may be too wide and the crystal oscillator (4) may not fit into the post ( 3) Inconveniences such as falling down occur. Therefore, it is necessary to use a machined post (3) that does not cause peripheral sag (9), but a machined post (3) is expensive.

■ Product yield is poor, that is, even if the post (3) is a machined product and the post (3) is coated with solder plating with good solder wettability, it is not possible to completely prevent the post (3) from shifting and tilting. Therefore, support the crystal oscillator (4).
The yield rate in the fixing process is not good.

■ Frequency adjustment accuracy is poor. That is, in the final manufacturing stage after supporting and fixing the crystal oscillator (4), the final frequency setting (fine adjustment of the oscillation frequency by metallising a part of the crystal oscillator in a vacuum) is performed. . The yield (frequency adjustment accuracy) at this final frequency setting is
The smaller the deviation in relative position between the substrate +11 and the crystal resonator (4), the better. The relative position of the substrate (1) and the crystal oscillator (4) is determined by the tolerance of the dimensions of the substrate 11+ and the printing position error of the thick film conductor (2), as well as the error of the thick film conductor (2) of the post (3).
) and the positional deviation of the crystal oscillator (4) within the post interval due to the size variation of the crystal oscillator (4). Therefore, the presence of the post (3) increases the relative positional deviation between the substrate (1) and the crystal resonator (4), which reduces the accuracy of frequency adjustment in the final frequency setting and reduces product yield. It is also one of the reasons why.

■ Low impact resistance as a finished product. That is, when a drop strength test is performed on a completed thick film integrated circuit, the crystal resonator (4) may be damaged by the impact. The higher the post (3) is, the greater the impact applied to the crystal resonator (4). As a shock mitigation measure, use L instead of post (3).
Another method is to use shape metal fittings.

However, it is difficult to automate and use a jig to fix the L-shaped metal fitting onto the thick film conductor (2), and it is difficult to apply the L-shaped metal fitting to mass-produced products.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method for attaching a crystal resonator that can reduce costs and improve yield.

Means for Solving the Problems To achieve the above object, the present invention provides a layer of a solderable material such as a thick film conductor on a supporting substrate such as a circuit board for mounting a thin plate-like vibrator. , supplying a predetermined amount of molten or unmolten solder or paste solder on the solder adhesive material layer, melting the solder when the solder is unmolten or pasty, and then applying the molten solder. Attachment of a vibrator characterized in that solder protrusions are formed by solidifying the solder protrusions, and the vibrator is fixed to the solder protrusions with a bonding material such as silver paste while keeping the solder protrusions in an unmolten state. is related to the method.

Function: If the molten solder is solidified in the solder protrusion forming step of the invention described above, hemispherical solder protrusions that follow the surface tension of the solder are formed. The shape of the solder protrusion is determined based on surface tension, substantially regardless of the shape of the supplied solder. Therefore, protrusions having a predetermined shape can be easily obtained, and the cost of the support structure for the crystal resonator can be reduced. Further, since the solder projections have a predetermined shape as described above, it becomes possible to attach the crystal resonator accurately, and the yield is improved.

Embodiment Next, a method and structure for mounting a crystal resonator in a thick film integrated circuit according to an embodiment of the present invention will be described with reference to FIGS. 1 to 8.

The circuit device including the crystal resonator shown in FIGS. 1, 2, and 3 is obtained by attaching the crystal resonator 01) shown in FIG. 4 to the support device shown in FIG. 5.

As is clear from Figure 4, the crystal oscillator circle has a diameter of 6.2
It is a disc-shaped thin plate of mm in diameter, and has one electrode (121) made of silver on its surface, and the other electrode 03 made of silver on its back surface, and a supporting conductor layer α41 (151) made of silver. Electrode α2 consists of a central circular part (12a) constituting an oscillating part and a strip lead-out part (12b) connected thereto.
and the connection terminal part (12C) on the outer peripheral edge of the crystal resonator (11).
), and the other electrode (13) consists of a central circular part (13a) constituting the oscillating part, a strip lead-out part (13b) connected thereto, and a connection terminal at the outer peripheral end of the crystal oscillator 01). (13c). In addition, the supporting conductor layer (14+
is arranged to face the terminal part (12C), and the supporting conductor layer 041 (15) and the terminal part (13C) are arranged at an angular interval of about 120 degrees so as to correspond to the apex position of an equilateral triangle. The thick film integrated circuit that supports the child ttn is made of an alumina circuit board (161) and a silver-palladium thick film conductor (+7) shown with diagonal lines in the upper right corner of FIGS. 3 and 5.
, Coloring as a positioning pattern arranged in an arc corresponding to the shape of the ruthenium oxide thick film resistor (181, crystal oscillator 01) shown with diagonal lines downward to the right in FIGS. 3 and 5. Consists of a glass layer (19a), a colored glass layer (19b) for preventing solder flow, and three solder protrusions (20) (2]) (221) provided on the thick film conductor 0D.Solder protrusions f20) ( 211+22) is bonded to the crystal resonator α1) by using a conductive adhesive (silver paste) without melting the solder protrusions (2QCI!υ). (c) shows a bonding conductor layer (2) made of silver paste. The electrical connection of the upper electrode α2 of the crystal oscillator α1 is made by a conductor (24) formed by applying silver paste and heat-treating it. , On the other hand, the electrical connection of the lower electrode 03) is performed by the bonding conductor layer CI!31 on the solder projection (a).

Next, the crystal resonator (
The method for installing Ill will be explained step by step.

First, a thick film conductor α and a thick film resistor 08) are formed on an insulating circuit board 06). Note that, in order to provide solder protrusions (20) (211 (221)) on the thick film conductor On in a later step, a conductor portion (17a) having a circular planar shape is provided as shown in FIG. 6 (4). In order to effectively utilize the surface of the substrate (+6), a thick film resistor is provided in the mounting area of the crystal resonator (01) as shown in Figure 5.Thick film resistor α barrel and crystal resonator (11) ) with the electrode αJ, there is no practical problem as long as it is about 20 μm or more in the case of a disc-shaped crystal resonator with a diameter of several mm.Therefore, in this example, the above-mentioned distance is set to about 200 μm. .

Next, as shown in FIGS. 5 and 6, a circular conductor (17
A colored glass layer (19b) is formed on the strip conductor (17b) continuous to a), and at the same time a colored glass layer (19a) is formed as a positioning pattern. Note that the glass layers (19a) (tc+b), the conductor αn, and the resistor side are each formed using a thick film technique using screen printing and heat treatment.

Next, liquid solder flux (2
51 as shown in FIG. 7, and Pb-Sn
Solder ball (261) made of eutectic solder (melting point 18'3 C)
Supply this solder ball c! Temporarily fix 6) with solder flux (Ken's adhesive strength).

Next, after melting the solder ball QO by heat treatment at 240C, it is cooled and solidified to form a hemispherical solder protrusion (A) as shown in Fig. 8. (2■ is shown, but the remaining solder protrusions CI!+1
(221 is formed in the same way 3. At this time, the solder protrusion (20
) (2υ is limited to the glass layer (19b) and is formed only on the circular conductor (17a), and the solder protrusion (2υ is formed only on the circular conductor (17a).
0+ (21) (The height of 221 is related to the amount of solder and the area of the circular conductor (17a), and if these are adjusted with high precision, it will inevitably be determined with high precision.

Next, silver paste is applied as a conductive adhesive onto each solder projection f20) (2+1 (22+), and then the glass layer (t9a) formed in an arc shape is used as a positioning pattern to ) is placed on the solder protrusion (201 (2υ) (221) through silver paste. At this time, the terminal part (13c) of the crystal resonator aυ (+31)
and supporting conductor layer α41+15+ with each solder protrusion (20+(
2υ(2′; Placed oppositely on top of 3. Then, about 15
00, and the resulting bonding conductor layer (c) forms each solder protrusion (2■ (2υ(a)).
The terminal portion (13c) and the conductor layer 041 (151) are fixed to the terminal portion (13c).

Note that in this step, in order to change the height of the solder protrusion (2) f2+) (221), heat treatment must be performed at a temperature lower than the melting point of the solder.

Next, connect the terminal part (12c) of the electrode C121 to the substrate (16).
In order to electrically connect to the upper conductor αη, a connecting conductor Q4 is provided as shown in FIGS. 1 and 3. That is, silver paste is applied from the terminal part (12C) to the bonding conductor layer (C) on the solder projection (0I), and then the silver paste is applied to the solder projection (4) (211
(Connection conductor c!4) is formed by heat treatment at a temperature that does not remelt 221.

This embodiment has the following advantages.

shaft) The post (
3) is no longer necessary, and the material cost is reduced accordingly. Note that the manufacturing cost for assembling the post (3) and the manufacturing cost for forming the solder projection (201 (2υ) (221) are almost the same, so the total product cost is reduced.

(b) Since the post (3) is not used, the inclination or misalignment of the post (3) or misalignment of the crystal oscillator (4) within the post spacing may reduce the yield of products (thick film integrated circuits). This problem does not occur. Therefore, the yield is improved.

(C1 has high impact resistance as a finished product. In other words, the support height of the crystal resonator (111) can be significantly smaller than that of the conventional crystal resonator (4) (approximately 1 mm or more). The smaller the height, the smaller the amount of deformation that acts on the crystal oscillator Qυ when the circuit board (161) is bent.For this reason, when the product is subjected to a drop strength test, the crystal oscillator (11) It is less likely to break.

(d) The yield of crystal resonators (Ill) is improved. In other words, even if there is considerable variation in the size of crystal resonators (Iυ), solder protrusions (2111 (211
(Adjusting the position when placing it on 221 will not cause any trouble.)

Therefore, it is now possible to use a crystal resonator that was previously supported by posts (3) and could not be used due to its large or small diameter.

(e) As a comprehensive result of the above (a) to (d), a reduction in product cost and an improvement in product reliability are achieved.

Modifications The present invention is not limited to the above-described embodiments, and, for example, the following modifications are possible.

Instead of supplying a solid solder ball (261), solder paste may be applied by printing and melted to form a solder protrusion (21111 (211(2z). Also, a circular conductor portion (17a) Molten solder may be supplied 17 to the conductor portion (17a) by a method such as bringing the solder into contact with a solder bath, and based on this, the solder protrusions (2(j) (211 (221) may be formed).

03) The bonding conductor layer (23+) may be formed with a conductive adhesive or bonding material other than silver paste. In addition, when forming the bonding conductor layer (23) with solder, solder protrusions (
J (21) (Use a solder with a lower melting point than 221.

It is also applicable when supporting (0 crystal oscillator θ1) at two points or four points.

■ In the example, the conductor layer □□□ above the solder projection (A) is directly used for electrical connection, and the other solder projections (211
(The conductor layer (to) above 221 is not directly used for electrical connection, but all solder protrusions (2(1(21+)
221 may not be used for electrical connection, but merely for mechanical support. In this case, the solder protrusion (
B) (21) (221) The circular conductor part (17a) under (221) may be replaced with a nonconductor or a layer of Ushida adhesive material with a large resistance value. The conductor layer Q41 (19) may be formed of a nonconductor or a material with a large resistance value.

(G) A part of the electrode (12+) may be led out in advance to the lower surface side of the crystal resonator ttn, and the step of forming the conductor (241) may be omitted.

Effects of the Invention According to the present invention, solder protrusions are formed by solidifying molten solder, and the vibrator is supported thereby, making it unnecessary to use expensive posts and reducing costs. . In addition, when using a post, it is difficult to keep the post attached in a constant state, but in the case of solder protrusions, if the amount of solder and the area of the soldering part are kept constant, the solder surface Based on the tension, solder protrusions having a substantially constant shape and constant height can be formed. Therefore,
Yield can be improved.

[Brief explanation of drawings]

1 is a sectional view of a portion corresponding to line A-A in FIG. 3 showing a part of a thick film integrated circuit including a crystal resonator according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a portion corresponding to line B in FIG. 3 is a plan view showing a part of the thick film integrated circuit, FIG. 4 is a plan view showing the crystal resonator shown in FIG. 1, and FIG.
The installation of the crystal resonator shown in the figure is a plan view showing the board, and Figure 6 (
4), FIG. 7(4), and FIG. 8(4) are plan views showing the solder protrusion forming portion in the order of steps, FIG. 6(B), and FIG. 703.
), and FIG. 8 CB) are C- in FIG. 6, FIG. 7 (4), and FIG.
FIG. 9 is a cross-sectional view of a portion corresponding to line C, FIG. 9 is a cross-sectional view showing a conventional support structure for a crystal resonator, and FIGS. 1O and 11 are cross-sectional views showing the state of the post in FIG. 9. Ql)...Crystal oscillator, (12+...- aromatic electrode,
(12c)...Terminal part, (Iri...other electrode, (
13c)...Terminal part, α similar [end...Supporting conductor layer, θ
6)...Substrate, (In...thick film conductor, (17a)...
...Circular conductor part, (110...Thick film resistor, (19a)
09b)...Glass layer, (21) (221...Solder protrusion, (support))...Joining conductor layer, (26)...Solder ball. Agent Noriyoshi Takano 4th figure 6th figure uj 7th figure 8th

Claims (1)

[Scope of Claims] (11) A layer of a solderable material is formed on a supporting base on which a thin plate-like vibrator is attached, and a predetermined amount of molten or non-melted or pasty material is formed on the solderable material layer. A solder projection is formed by supplying solder, melting the solder when the solder is unmolten or paste-like, and then solidifying the molten solder, and forming a solder projection by keeping the solder projection in an unmolten state. A method for attaching a vibrator, characterized in that the vibrator is fixed with a bonding material. (2) The vibrator according to claim 1, wherein the solderable material layer is a thick film conductor. The attachment is a method. (3) Claim 1, wherein the solder adhesive material layer is formed at three locations corresponding to the apex positions of a triangle.
How to install the vibrator described in Section 2 or Section 2. (4) Forming the solder projections includes supplying solid solder balls onto the layer of solder adhesive material, melting the solder balls, and then solidifying the solder balls.
The method for installing the vibrator described in Section 2 or Section 2 or Section 3. (5) A method for attaching a vibrator according to claim 1 or 2 or 3 or 4, wherein the bonding material is a conductive bonding material. (6) A method for attaching a vibrator according to claim 5, wherein the bonding material is silver paste. (7) The vibrator is attached by method 1 according to claim 1, 2, 3, 4, or 5, wherein the vibrator is a crystal vibrator.