JP2015133755A - Oscillator and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oscillator and a manufacturing method of the same, which can inhibit the occurrence of solder cracks associated with a temperature change by a simple composition and at low cost, and improve heat cycle resistance.SOLUTION: In an oscillator, an electronic component 2 is lifted up by a land pattern 4 of an electrode formed on a substrate 1 and a solder resist 8c formed to cover a part of the land pattern 4 to form a space between a component electrode 3 and the land pattern 4, and a packaging solder 5 filled in the space and a fillet shape of the packaging solder 5 is formed on lateral faces of the component electrode 3 to increase adhesion of the packaging solder 5.

Description

  The present invention relates to an oscillator using a circuit board made of glass epoxy resin, and more particularly to an oscillator having improved heat cycle performance by reducing distortion to solder and a method for manufacturing the same.

[Conventional technology]
Conventionally, some crystal oscillators use glass epoxy resin as a circuit board.
A metal electrode pattern is formed on the circuit board, and an electronic component such as ceramic is mounted on the electrode pattern by soldering.

[Conventional crystal oscillator: Fig. 7]
A conventional crystal oscillator will be described with reference to FIG. FIG. 7 is a cross-sectional explanatory diagram of a conventional crystal oscillator.
As shown in FIG. 7, the conventional crystal oscillator has a metal land pattern (electrode pattern) 4 and a solder resist 8 formed on an epoxy resin substrate 1, and a circuit component (electronic component) on the electrode pattern 4. 2 is mounted.
Specifically, a part electrode 3 is formed at a portion where the electronic component 2 is connected to the land pattern 4, and the component electrode 3 and the land pattern 4 are fixed by mounting solder 5.

[Related technologies]
As related prior arts, Japanese Patent Application Laid-Open No. 11-135684 “Semiconductor Device and Manufacturing Method” (Kansai NEC Corporation) [Patent Document 1], Japanese Patent Application Laid-Open No. 2000-332396 “Electronic Component Mounting Structure” (Alps Electric Co., Ltd.) [Patent Document 2], Japanese Patent Application Laid-Open No. 2008-238253, “Pb-free solder connection material and method for manufacturing semiconductor mounting structure using the same” (Hitachi, Ltd.).

  Patent Document 1 discloses a semiconductor device that can connect a semiconductor pellet having fine pitch bump electrodes to a wiring board by forming a wide solder supply portion in a fine conductive pattern.

  In Patent Document 2, an insulating layer for applying an adhesive for temporarily fixing an electronic component in a mounting area for mounting the electronic component is formed to be thicker than a circuit pattern, and the electronic component mounted on the insulating layer is An electronic component mounting structure in which a predetermined gap is formed between the lower surface and the circuit pattern is shown.

  In Patent Document 3, when a low heat-resistant leadless component is mounted by using a solder paste in which Sn-Zn solder powder and Sn powder or Zn powder having a higher melting point are mixed as a solder connection material, It is shown that the tilt control of parts and the securing of the thickness of the connection part are realized.

Japanese Patent Laid-Open No. 11-135684 JP 2000-332396 A JP 2008-238253 A

  However, in the above-mentioned conventional oscillator, distortion is concentrated on the mounting solder in a use environment where a heat cycle occurs due to a difference in thermal expansion coefficient between an electronic component (circuit component) using ceramic or the like and a circuit board of glass epoxy resin, There was a problem that cracks occurred in the solder.

  In particular, in the Oven Controlled Crystal Oscillator (OCXO), the temperature change from the ambient temperature to the thermostatic chamber control temperature (for example, 85 ° C) is turned on / off in an environment where the power is repeatedly turned on and off. Since it is added every time, a crack occurs in the solder, and there is a problem in long-term reliability.

  In Patent Document 1, a solder supply portion is provided to facilitate the supply of solder to a conductive pattern formed on a substrate. The thickness of the land pattern serving as an electrode is utilized to make the land pattern On the other hand, the electronic component is not lifted to form a space where solder can be easily filled between the land pattern and the component electrode formed on the electronic component.

  Moreover, in patent document 2, although the insulating layer which has an application part for apply | coating the adhesive which temporarily fixes an electronic component is formed, a clearance gap is formed between a circuit pattern and an electronic component. In order to lift up, it is necessary to form a dedicated insulating layer, and it is not possible to realize a configuration in which a normal process for manufacturing a circuit board is devised and lifted up simply.

  Further, in Patent Document 3, a metal spacer is formed on a pad on a mounting substrate, a semiconductor element is mounted, and soldering is performed in a gap portion. Soldering does not increase the amount of solder and form a fillet shape to strengthen the adhesion.

  The present invention has been made in view of the above circumstances, and provides an oscillator capable of suppressing the occurrence of solder cracks accompanying temperature changes at a low cost with a simple configuration and improving the heat cycle performance and a method for manufacturing the same. For the purpose.

  The present invention for solving the problems of the above conventional example is an oscillator comprising an epoxy resin substrate and electronic components mounted on the substrate, the electrode land pattern formed on the substrate, and the electrode A solder resist formed so as to cover a part of the center side of the electronic component, and a component electrode formed at the end of the electronic component by lifting the electronic component with the land pattern of the electrode and the solder resist And mounting solder for soldering the electrode land pattern to each other.

  The present invention is characterized in that the oscillator is applied to a crystal oscillator with a thermostatic bath.

  The present invention relates to an oscillator manufacturing method comprising an epoxy resin substrate and an electronic component mounted on the substrate, wherein an electrode land pattern is formed on the substrate, and the electrode land pattern is an electronic component A solder resist was formed so as to cover a part of the center side, solder was applied on the land pattern of the electrode, an electronic component was mounted on the solder resist, and the electronic component was lifted by the land pattern of the electrode and the solder resist. In this state, the component electrode formed on the end portion of the electronic component and the land pattern of the electrode are solder-connected by reflow.

  According to the present invention, an electrode land pattern formed on a substrate, an electrode land pattern, which is a solder resist formed so as to cover a part of the center side of an electronic component, an electrode land pattern, and a solder Since the electronic component is lifted by the resist, and the oscillator has a component electrode formed on the end of the electronic component and a mounting solder for soldering the land pattern of the electrode, the solder can be formed thick and the adhesion can be strengthened. With a simple configuration, there is an effect that the generation of solder cracks accompanying a temperature change can be suppressed at low cost and the heat cycle resistance can be improved.

It is a plane explanatory view of the first oscillator. FIG. 6 is a manufacturing sectional view of the first oscillator. It is a section explanatory view of the 1st oscillator. It is manufacturing cross-sectional explanatory drawing which shows the application example of a 1st oscillator. It is a cross-sectional explanatory view of the second oscillator. It is manufacturing cross-sectional explanatory drawing of a 3rd oscillator. It is sectional explanatory drawing of the conventional crystal oscillator.

Embodiments of the present invention will be described with reference to the drawings.
[Outline of the embodiment]
In the oscillator according to the embodiment of the present invention, a lifting portion for lifting an electronic component is formed on a circuit board made of glass epoxy resin, and a portion of the electrode land pattern formed on the substrate is in contact with the component electrode of the electronic component. In addition, the space formed between the component electrode and the land pattern is filled with mounting solder, and the mounting solder is formed in a fillet shape on the side surface of the component electrode. Bonding becomes strong, and the distortion of the mounting solder caused by the temperature change from the difference in thermal expansion coefficient between the electronic component and the glass epoxy resin material can be relaxed, and the heat cycle resistance can be improved.

[First oscillator: FIGS. 1 and 2]
An oscillator (first oscillator) according to a first embodiment of the present invention will be described with reference to FIGS. 1, 2, and 3. FIG. FIG. 1 is an explanatory plan view of the first oscillator, FIG. 2 is an explanatory sectional view of the first oscillator, and FIG. 3 is an explanatory sectional view of the first oscillator.
As shown in FIGS. 1 and 3, the first oscillator has a metal land pattern (electrode pattern) 4 and a dummy land pattern 7 formed on an epoxy resin substrate 1. A solder resist 8 a is formed on 7, and a circuit component (electronic component) 2 is mounted on the land pattern 4.
The electronic component 2 is made of, for example, ceramic, and the solder resist 8a is made of, for example, a thermosetting epoxy resin.

Specifically, a component electrode 3 is formed at a portion where the electronic component 2 is connected to the land pattern 4. That is, the component electrode 3 is formed at the end of the electronic component 2.
Then, the electronic component 2 is lifted from the land pattern 4 by the thickness of the solder resist 8a by the lifting portion where the dummy land pattern 7 and the solder resist 8a are stacked at the center portion of the bottom surface of the electronic component 2. That is, the dummy land pattern 7 and the solder resist 8 a form a lifting portion for lifting the electronic component 2.
Further, the component electrode 3 and the land pattern 4 are fixed by mounting solder 5.

Here, the solder resist 8a is laminated on the dummy land pattern 7, but the solder resist 8a is not laminated on the land pattern 4 serving as an electrode.
Since the dummy land pattern 7 and the land pattern 4 are formed in the same process, the thickness is the same, and the electronic component 2 is formed by the thickness of the solder resist 8a laminated on the dummy land pattern 7. Lifted.

However, since the component electrode 3 is formed on the electronic component 2 on the land pattern 4, the gap between the component electrode 3 and the land pattern 4 is smaller than the lifting width.
The mounting solder 5 is filled in the gap between the land pattern 4 and the component electrode 3, and the mounting solder 5 is formed in a fillet shape between the land pattern 4 and the side surface of the component electrode 3.

Further, as the material of the epoxy resin of the substrate 1, CEM-3 (Composite Epoxy Material 3), FR-4 (Flame Retardant Type 4) or the like is used.
CEM-3 is a glass epoxy substrate and is based on a plate in which glass fibers and an epoxy resin are mixed.
FR-4 is a glass epoxy substrate, which is based on a plate made by impregnating a cloth knitted with glass fibers with an epoxy resin.

The metal layers of the land pattern 4 and the dummy land pattern 7 are generally formed with a thickness of about 10 to 50 μm, and in the case of FIG. 1, for example, the thickness is about 45 to 50 μm.
The thickness of the solder resist 8a is about 10 μm.
2 and 3, the solder resist 8a is drawn, but is omitted in FIG. 1 for clarity.

[First Oscillator Manufacturing Method: FIG. 2]
Next, a method for manufacturing the first oscillator will be described with reference to FIGS. FIG. 2 is a manufacturing cross-sectional explanatory view (1) of the first oscillator.
As shown in FIG. 2A, the first oscillator forms a land pattern 4 and a dummy land pattern 7 as electrodes on a substrate 1 made of epoxy resin with a metal film.
The dummy land pattern 7 is formed at the central portion of the position where the electronic component 2 is mounted, and the land pattern 4 is formed at a position where the component electrode 3 attached to the electronic component 2 is connected.

Next, as shown in FIG. 2B, a solder resist 8 a is formed at a necessary location on the substrate 1 so as to cover the dummy land pattern 7.
Here, the solder resist 8a is not formed so as to cover the land pattern 4 of the electrode.
Then, the mounting solder 5 is applied on the land pattern 4, the electronic component 2 is mounted on the place where the dummy land pattern 7 and the solder resist 8 a are laminated, and the component electrode 3 is positioned on the land pattern 4. Is done.

  Specifically, since the electronic component 2 is lifted by the thickness of the dummy land pattern 7 and the solder resist 8a, the mounting solder is placed in the space (gap) formed between the component electrode 3 and the land pattern 4. 5 is filled, and after reflow, a fillet shape of the mounting solder 5 is formed on the side surface of the component electrode 3.

According to the first oscillator, the amount of mounting solder 5 for bonding the land pattern 4 and the component electrode 3 is increased (thicker) compared to the conventional configuration shown in FIG. Adhesion with the electrode 3 can be strengthened.
As a result, even if the substrate 1 on which the land pattern 4 is formed and the electronic component 2 on which the component electrode 3 is formed have different thermal expansion coefficients, the distortion of the mounting solder 5 caused by the temperature change is alleviated. There is an effect that heat cycle performance can be improved.

[Application example of first oscillator: FIG. 4]
Next, an application example of the first oscillator will be described with reference to FIG. FIG. 4 is a manufacturing cross-sectional explanatory view showing an application example of the first oscillator.
The application example of the first oscillator shown in FIG. 4 has a two-layer solder resist as compared with FIG. 3 to increase the lifting width of the electronic component 2.
Since the thicknesses of the solder resists 8a and 8b are about 10 μm, respectively, when the two layers are used, the thickness is about 20 μm. It is lifted about 10 μm higher than the first oscillator.

Specifically, as shown in FIG. 4C, land patterns 4 and 7 are formed on the substrate 1, solder resist 8a is formed on the dummy land pattern 7 and the substrate 1, and the solder resist is further formed. A solder resist 8b is formed on 8a.
Then, the mounting solder 5 is applied on the land pattern 4, the electronic component 2 is arranged on the solder resist 8 b, and the electronic component 2 is lifted from the land pattern 4, and the component electrode 3 and the land pattern 4 are The space (gap) formed therebetween is filled with the mounting solder 5, and after reflowing, a fillet shape of the mounting solder 5 is formed on the side surface of the component electrode 3.

  According to the application example of the first oscillator, the gap between the land pattern 4 and the component electrode 3 is larger than that of the first oscillator shown in FIG. The land pattern 4 and the component electrode 3 can be firmly bonded, and even if the substrate 1 and the electronic component 2 have different coefficients of thermal expansion, the distortion of the mounting solder 5 caused by temperature changes can be alleviated and the heat cycle resistance can be reduced. There is an effect that the performance can be improved.

[Second oscillator: FIG. 5]
Next, an oscillator (second oscillator) according to a second embodiment of the present invention will be described with reference to FIG. FIG. 5 is a cross-sectional explanatory diagram of the second oscillator.
As shown in FIG. 5, the second oscillator has the silk printed layer 9 formed on the upper surface of the solder resist 8 a in the first oscillator of FIG. 3, and the electronic component 2 is mounted on the silk printed layer 9. Is.
The silk printing layer 9 is an insulating ink layer formed by silk screen printing (silk printing) technology.

Therefore, in the electronic component 2, the component electrode 3 is lifted from the land pattern 4 by the dummy land pattern 7, the solder resist 8 a, and the silk print layer 9. That is, the dummy land pattern 7, the solder resist 8a, and the silk print layer 9 form the lifted portion.
Here, the silk printed layer 9 has a thickness of about 10 μm.

  Generally, since resist formation and silk printing are performed in an oscillator manufacturing process, the silk printing is used. Compared to the first oscillator application example, solder resists 8a and 8b are formed in two layers. Thus, the process is not wasted.

  In the second oscillator, the solder resist 8a and the silk printing layer 9 have a thickness of about 20 μm, and the same thickness as that of the first oscillator application example (the solder resist 8a is about 10 μm + the solder resist 8b is About 10 μm = about 20 μm), and the lifting effect of the electronic component 2 is obtained.

  According to the second oscillator, by forming the solder resist 8a and the silk print layer 9 on the dummy land pattern 7, the space formed between the land pattern 4 and the component electrode 3 can be increased. The amount of mounting solder 5 that fills the space increases, and the adhesion between the land pattern 4 and the component electrode 3 can be strengthened. As a result, even if the substrate 1 and the electronic component 2 have different thermal expansion coefficients, There is an effect that the distortion of the mounting solder 5 caused by the change can be alleviated and the heat cycle resistance can be improved.

[Third oscillator: FIG. 6]
Next, an oscillator (third oscillator) according to a third embodiment of the invention will be described with reference to FIG. FIG. 6 is an explanatory diagram of a manufacturing cross section of the third oscillator.
As shown in FIG. 6A, the third oscillator has a land pattern 4 formed on the substrate 1 and covers a part of the land pattern 4 as shown in FIG. 6B. A resist 8c is formed.
Here, the land patterns 4 and 7 have a thickness of about 45 to 50 μm, and the solder resist 8 c has a thickness of about 10 μm.

The part of the land pattern 4 on which the solder resist 8c is formed is a part on the center side of the electronic component 2 to be mounted.
In FIG. 6, the solder resist 8 c is formed on the entire lower side of the electronic component 2, and the solder resist 8 c is formed so as to cover a part of the opposing land pattern 4.

  Furthermore, it is desirable that the solder resist 8c be connected to such an extent that it supports a part of the component electrode 3 on the substrate 1 side. If the solder resist 8c blocks between the land pattern 4 and the component electrode 3, adhesion by the mounting solder 5 will be weakened. For this reason, it is preferable to form a space between the component electrode 3 and the land pattern 4 and strengthen the adhesion by the mounting solder 5.

  Then, as shown in FIG. 6C, the mounting solder 5 is applied to the land pattern 4 so that the component electrode 3 of the electronic component 2 is in contact with the solder resist 8c formed on the land pattern 4. When 2 is mounted, the space formed between the component electrode 3 and the land pattern 4 is filled with the mounting solder 5, and after reflow, a fillet shape of the mounting solder 5 is formed on the side surface of the component electrode 3.

According to the third oscillator, the electronic component 2 is lifted by the solder resist 8c formed so as to cover a part of the land pattern 4, and a space (gap) is formed between the component electrode 3 and the land pattern 4. Therefore, the mounting solder 5 is filled in the space, and the fillet shape of the mounting solder 5 is formed on the side surface of the component electrode 3, so that the bonding of the mounting solder 5 can be strengthened.
That is, a part of the land pattern 4 and the solder resist 8 c formed thereon constitute a lifting portion that lifts the electronic component 2.

  The technique applied to the third oscillator can also be applied to small parts. In other words, in the first and second oscillators, it is necessary to form a lifting portion between the land patterns 4 serving as electrodes, so this is not suitable for small parts. If accuracy is sufficient, it can be handled.

[Effect of the embodiment]
According to the first oscillator, since a space is formed between the land pattern 4 and the component electrode 3, the amount of the mounting solder 5 for bonding the two increases, and the land pattern 4 and the component electrode 3 are bonded. Thus, even if the substrate 1 on which the land pattern 4 is formed and the electronic component 2 on which the component electrode 3 is formed have different thermal expansion coefficients, the distortion of the mounting solder 5 caused by the temperature change can be reduced. It has the effect of relaxing and improving heat cycle performance.

  According to the application example of the first oscillator, the space formed between the land pattern 4 and the component electrode 3 can be increased by covering the dummy land pattern 7 with two layers of solder resists 8a and 8b. The amount of mounting solder 5 that fills the space increases, and the adhesion between the land pattern 4 and the component electrode 3 can be strengthened, so that even if the substrate 1 and the electronic component 2 have different thermal expansion coefficients, There is an effect that the distortion of the mounting solder 5 caused by the temperature change can be alleviated and the heat cycle performance can be improved.

  According to the second oscillator, by forming the solder resist 8a and the silk print layer 9 on the dummy land pattern 7, the space formed between the land pattern 4 and the component electrode 3 can be increased. The amount of mounting solder 5 that fills the space increases, and the adhesion between the land pattern 4 and the component electrode 3 can be strengthened. As a result, even if the substrate 1 and the electronic component 2 have different thermal expansion coefficients, There is an effect that the distortion of the mounting solder 5 caused by the change can be alleviated and the heat cycle resistance can be improved.

  According to the third oscillator, the electronic component 2 is lifted by the solder resist 8c formed so as to cover a part of the land pattern 4, and a space is formed between the component electrode 3 and the land pattern 4. Therefore, the mounting solder 5 is filled in the space, and the fillet shape of the mounting solder 5 is formed on the side surface of the component electrode 3, so that the bonding of the mounting solder 5 can be strengthened. However, even if the thermal expansion coefficients are different, there is an effect that the distortion of the mounting solder 5 caused by the temperature change can be alleviated and the heat cycle resistance can be improved.

  In the first to third oscillators, it is more effective to apply to a crystal oscillator with a thermostatic bath.

  INDUSTRIAL APPLICABILITY The present invention is suitable for an oscillator capable of suppressing the occurrence of solder cracks accompanying temperature changes at a low cost with a simple configuration and improving the heat cycle resistance and a method for manufacturing the same.

  DESCRIPTION OF SYMBOLS 1 ... Board | substrate, 2 ... Electronic component, 3 ... Component electrode, 4 ... Land pattern, 5 ... Mounting solder, 7 ... Dummy land pattern, 8, 8a, 8b, 8c ... solder resist, 9 ... silk printing layer

Claims (3)

An oscillator comprising an epoxy resin substrate and electronic components mounted on the substrate,
A land pattern of electrodes formed on the substrate;
A solder resist formed so as to cover a part of the center side of the electronic component in the land pattern of the electrode;
The electronic component is lifted by the land pattern of the electrode and the solder resist, and includes a component electrode formed at an end of the electronic component and a mounting solder for solder-connecting the land pattern of the electrode. Oscillator.   2. The oscillator according to claim 1, wherein the oscillator is applied to a crystal oscillator with a thermostatic bath. An oscillator manufacturing method comprising an epoxy resin substrate and an electronic component mounted on the substrate,
Forming an electrode land pattern on the substrate;
Form a solder resist so as to cover a part of the center side of the electronic component in the land pattern of the electrode,
Apply solder on the electrode land pattern,
The electronic component is mounted on the solder resist,
In the state where the electronic component is lifted by the land pattern of the electrode and the solder resist, the component electrode formed at the end portion of the electronic component and the land pattern of the electrode are solder-connected by reflow. A method for manufacturing an oscillator.

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