JPH1154892A - Method and structure for attaching electronic component to glass fluororesin substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attach an electronic component on a substrate directly with a bonding agent for improved workability by so coating a solder resist at an electronic component attaching position of the substrate as to almost conform to a contact shape to be dried, then coating a bonding agent for bonding an electronic component over it. SOLUTION: At an attaching position of an electronic component 11 on a Teflon(R) substrate 12, a solder resist 17 is formed in a specified pattern through film-forming and thermosetting by silk screen printing. Then, a bonding agent 14 is coated on the Teflon substrate by an automatic attaching machine, and the electronic component 11 is mounted. After the bonding agent has been solidified, the Teflon substrate 12 is attached to a case 13. By forming the solder resist 17 on the Teflon substrate 12, the electronic part 11 is allowed to be bonded directly, so that the need for separate component which causes rise in cost to be eliminated. Further, such manual work as the coating of a bonding agent, screwing the electronic component 11, etc., can be reduced for improved workability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and structure for mounting an electronic component on a printed wiring board, and more particularly, to a glass fluororesin substrate (hereinafter, "Teflon substrate").
On which electronic components are mounted using an adhesive.

[0002]

2. Description of the Related Art Conventionally, to mount electronic components on a general printed wiring board, a hole is formed in the printed wiring board,
2. Description of the Related Art A method is known in which a lead wire or a fixed terminal of an electronic component is passed through a hole of the printed wiring board, and the lead wire or the fixed terminal that has passed through the back surface of the printed wiring board is bent or soldered and mounted. . In recent electronic components, the number of surface-mounted chip-type components has been increasing due to the miniaturization of the components, and such chip components are temporarily placed on a printed circuit board with an adhesive for positioning. There is known a method of performing temporary fixing and then performing final fixing and electrical connection by soldering or the like and mounting. In some cases, the adhesive is finally fixed by the adhesive itself.

Here, as a material of a normal printed wiring board, a phenol resin or epoxy resin board based on paper or glass fiber is generally used, but in a circuit of a microwave frequency, As the frequency used increases, if the conventional substrate material is used as it is, the loss due to the substrate material increases. Therefore, a Teflon substrate using Teflon (registered trademark) is used as a material of a printed wiring board of a circuit handling microwaves of several tens of GHz or the like.

As an example, in the case of a microwave detector configured to emit an alarm upon detecting a microwave emitted from a radar-type speed measuring device, for example, only the 10 GHz band (X band) has been conventionally used. However, recently, microwaves in a high frequency region such as a 25 GHz band (K band) and a 35 GHz band (Ka band) are also used.
In order to accurately detect such high-frequency microwaves,
It is necessary to use a Teflon substrate for the substrate of the microwave circuit portion.

A Teflon substrate using this Teflon is:
As described above, the attenuation of microwaves in the high band is less than that of a substrate made of a normal material, and in addition, it is used as a lubricant in coating materials for frying pans and oil of motors, etc. It is known that Teflon has excellent properties and strength and that the surface of Teflon is very smooth.

However, since the surface of the Teflon substrate is very smooth, conversely, when the electronic component is mounted with an adhesive, the electronic component side can be bonded, but the Teflon substrate side cannot. Was.

Therefore, as shown in the cross-sectional view of the conventional method of mounting an electronic component in FIG. 1, the electronic component (in the case of a microwave detector, for example, a dielectric resonator) is mounted on the substrate mounting surface side. After separately preparing a support 5 that can support the electronic component 1 having a threaded foot made of ceramic or plastic, and bonding the electronic component 1 and the support 5 with an adhesive 4,
The electronic component 1 is mounted at a predetermined position on the Teflon substrate by fixing the support base 5 to the housing 3 to which the Teflon substrate 2 is fixed by screws or the like. In this case, the electronic component 1
Is not directly mounted on the Teflon substrate 2, but is indirectly fixed at a predetermined position on the Teflon substrate 2 via the support 5 and the housing 3.

When the electronic component 1 needs to be electrically connected by soldering, the microstrip electrode 6 is wired close to the electronic component 1 so that the microstrip electrode 6 can be connected to the electronic component 1. In the case where is a dielectric resonator, there is no need to wire in particular nearby.

[0009]

However, the above-mentioned conventional method requires a support, which is a separate component, and the housing requires an operation of forming a threaded hole for fixing the support. The only method of bonding the electronic component and the support and screwing the bonded electronic component and the support into the housing has to be performed manually.

[0010] Therefore, the support of the separate component is a factor of increasing the cost, and the mounting of the electronic component is a manual operation, which is a factor of increasing the man-hour.

SUMMARY OF THE INVENTION The present invention has been made in view of the above background, and has as its object to solve the above-mentioned problems and increase the cost by mounting an electronic component on a glass fluororesin substrate. It is an object of the present invention to provide a method for mounting an electronic component on a glass fluororesin substrate, which does not require the use of an automatic mounting machine, and can improve the operability by mounting the electronic component. Another object of the present invention is to provide a mounting structure that is easy to mount and has a small number of components.

[0012]

According to the method of mounting an electronic component on a glass fluororesin substrate according to the present invention, when mounting an electronic component on a glass fluororesin substrate, the mounting position of the electronic component on the glass fluororesin substrate is reduced. Then, apply a solder resist so that the shape of the contact part of the electronic component to the glass fluororesin substrate except for the electrode part is approximately the same as that of the contact part, and then dry. Apply an adhesive for bonding the electronic component to the upper surface of the solder resist. Then, the electronic component is mounted (claim 1). In the method of mounting an electronic component on the glass fluororesin substrate according to the first aspect, the mounting of the electronic component on the glass fluororesin substrate by the adhesive can be realized by forming the solder resist on the glass fluororesin substrate. .

The area of the solder resist to be applied is as follows:
The area of the outer shape of the contact portion of the electronic component with the glass fluororesin substrate is preferably larger than the area of the outer shape. In the method of mounting an electronic component on the glass fluororesin substrate according to the second aspect of the present invention, by making the application area of the solder resist larger than the contact area of the electronic component, even if the adhesive protrudes at the time of bonding, it protrudes. The part is also adhered to the solder resist so that the protruding part does not rise.

Further, various types of electronic components can be applied, and for example, a dielectric ceramic component can be used (claim 3). In the method for mounting an electronic component on the glass fluororesin substrate according to the third aspect, in the case of a dielectric ceramic component in which the mass of the electronic component to be bonded is larger than that of a normal chip component, it is necessary to obtain further adhesive strength. Yes, the required adhesive strength can be obtained by bonding the entire contact surface of the electronic component.

In the method of mounting an electronic component on a glass fluororesin substrate according to a fourth aspect, an automatic mounting machine is used when mounting the electronic component on the glass fluororesin substrate. In the method of mounting an electronic component on the glass fluororesin substrate according to the fourth aspect, by using an automatic mounting machine, it is possible to automate the application of the adhesive and the positioning and mounting of the electronic component.

In the structure for mounting an electronic component on a glass fluororesin substrate according to the present invention, a solder resist is provided at a predetermined position on the surface of the glass fluororesin substrate, and the electronic component is mounted on the surface of the solder resist via an adhesive. It is configured to be bonded and fixed (claim 5). In this case, the glass fluororesin substrate is a substrate for forming a local oscillation circuit of a microwave detector, and the electronic component can be a dielectric resonator.
According to the sixth aspect, for example, a microwave detector that detects microwaves in the K band or the Ka band with high sensitivity can be manufactured with a small number of parts at low cost and high performance.

[0017]

FIG. 2 shows an embodiment of a mounting method and a mounting structure of an electronic component on a glass fluororesin substrate according to the present invention, and shows a cross section when the electronic component is mounted on a Teflon substrate. FIG. As shown in FIG. 1, the electronic component 11 is a relatively heavy electronic component such as a dielectric resonator made of dielectric ceramic. In the present embodiment,
Although a component having a large mass has been illustrated, the present invention can be implemented with other components as long as the component can be mounted by a normal automatic mounting machine.

The Teflon substrate 12 is fixed to a casing 13 to be described later by screws or the like. Teflon is less attenuated in a microwave frequency band of several tens of GHz or more than a normal substrate material. Used. The housing 13 is a housing of a device that processes microwaves, such as a microwave receiving antenna, and houses the Teflon substrate 12 therein. Then, the electronic component 11 is bonded and fixed to a predetermined position on the surface of the Teflon substrate 12 using an adhesive 14. The adhesive 14 used here is, for example, an ordinary adhesive such as paper phenol or glass epoxy used for mounting electronic components on a printed wiring board.

On the surface of the Teflon substrate 12, microstrip electrodes 16 having a predetermined pattern are formed. Like the microstrip electrode 6 in the above description of the related art, when the electronic component 11 is a component that requires electrical connection by soldering, the electrode 16 is close enough to be connected to the electronic component 11. However, when the electronic component 11 is a dielectric resonator, there is no need to particularly wire the electronic component 11 nearby.

In the present invention, a solder resist 17 is formed at a predetermined position on the surface of the Teflon substrate 12 on which the electronic component 11 is mounted, and the adhesive 14 is applied to the surface of the solder resist 17 while the electronic component 11 is coated. 11 is adhesively fixed. The solder resist 17 used here is, for example, S-22 made of epoxy resin.
L (manufactured by Taiyo Ink) is a resist film for forming a portion that is not soldered even when dipped in a solder dip layer formed on a printed wiring board by a method such as silk screen printing.

One embodiment of a method for mounting an electronic component on a Teflon substrate to form the above mounting structure is as follows.
First, a solder resist 1 is formed on a Teflon substrate 12 in a predetermined pattern at a mounting position of the electronic component 11 by a method such as silk screen printing and then thermally cured.
7 is formed. The Teflon substrate 12 on which the solder resist 17 is formed is automatically mounted (automatic mounting machine / automatic insertion machine).
Thereby, application of the adhesive 14 and mounting of the electronic component 11 are performed. Then, when the adhesive 14 is solidified, the mounting of the electronic component 11 is completed. Thereafter, the Teflon substrate 12 on which the electronic components 11 are mounted is attached to the housing 13 by screws or the like, and the operation is completed.

As described above, in the Teflon substrate on which the solder resist is formed, the direct mounting of the electronic component on the Teflon substrate by the adhesive eliminates the necessity of using a separate component which increases the cost. Thus, the electronic components can be mounted, so that manual operations such as application of an adhesive and screwing of the electronic components can be reduced, and workability can be improved.

The reason why the solder resist 17 is firmly printed (fixed) on the Teflon substrate 12 is as follows. That is, the surface of the Teflon substrate 12 is roughened due to the close contact of the copper foil for forming the printed wiring. The portion where the solder resist 17 is provided has its copper foil removed by etching, and the surface of the Teflon substrate 12 is exposed. At least the portion where the solder resist 17 is to be provided is not subjected to mechanical polishing (only chemical polishing is performed) on the exposed surface, leaving a rough surface to some extent. Therefore, the solder resist 17 adheres to the rough surface of the Teflon substrate 12 by the anchor effect.

In the above-described embodiment, an example has been described in which the shapes of the solder resist 17 and the electronic component 11 are substantially the same, but the present invention is not limited to this, and any of them may be enlarged. And as an example, it can be as shown in FIG. In the illustrated example, the solder resist 1
This is an example in which 7 is larger than electronic component 11. Further, in the illustrated example, the solder resist 17 is
a and the outer region 17b are separated by a ring-shaped groove 17c. Then, as shown in FIG. 2B, the shape of the inner region 17a is made substantially coincident with the planar shape of the electronic component 11. As a result, the portion of the concave groove 17c is
It can be used as a guide for positioning when mounting the. Furthermore, depending on the relationship between the thickness of the solder resist 17 (depth of the concave groove 17c) and the amount of the adhesive to be applied, even if the amount of the adhesive is large, a part of the adhesive can be stored in the concave groove 17c, The outflow to the outside can be suppressed, and since the adhesive is stored in the concave groove 17c, a large amount of the adhesive adheres to the outer peripheral edge of the electronic component 11, thereby increasing the adhesive force. It is needless to say that the concave groove 17c is not necessarily provided.

FIG. 4 shows an example of a specific application of the mounting structure described in each of the above embodiments. The figure is applied to a microwave detector 20. A three-dimensional circuit component 21 formed by aluminum die casting or the like has an open-side horn antenna 21a and a back-side local oscillator cavity 21b. Is formed. The Teflon substrate 22 is screwed into the cavity 21b with screws 25. And
On the upper surface of the Teflon substrate 22, a local oscillator and other circuit patterns by a microwave strip line are formed, and a dielectric resonator 23 which is an electronic component constituting a part of the local oscillator is adhered and fixed. .

An adjusting member 24 is mounted above the dielectric resonator 23. By adjusting the distance between the adjusting member 24 and the dielectric resonator 23, characteristics such as resonance frequency can be adjusted. It is supposed to do. In the present invention, when the dielectric resonator 23 is bonded and fixed, the solder resist 17 is formed on the upper surface of the Teflon substrate 22 as described above.
Is provided. Note that the three-dimensional circuit component 21 corresponds to the housing 13 in FIG. It goes without saying that the microwave detector has various components such as a substrate on which the circuit is mounted and a detection circuit in addition to the three-dimensional circuit components shown in the figure.

[0027]

As described above, according to the present invention, by forming a general solder resist, it is possible to mount an electronic component directly on a Teflon substrate by using an adhesive. As a result, an electronic component can be mounted by an automatic mounting machine without requiring a separate component which increases the cost, and manual work can be reduced and workability can be improved.

Further, since the bonding area can be increased, the bonding strength can be increased, and the use of a hole in the housing, the use of the support table, and the number of manual operations can be reduced. In addition, the reliability of the product can be improved, and the life can be prolonged.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a conventional method of mounting an electronic component on a Teflon substrate.

FIG. 2 is a cross-sectional view showing one embodiment of a method for mounting an electronic component on a Teflon substrate according to the present invention.

FIG. 3 is a view showing another embodiment of a method of mounting an electronic component on a Teflon substrate according to the present invention.

FIG. 4 is a diagram showing an example applied to a microwave detector.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Electronic component 12 Teflon board 13 Case 14 Adhesive 16 Microstrip electrode 17 Solder resist

Claims (6)

[Claims] When mounting an electronic component on a glass fluororesin substrate, a contact portion of the electronic component on the glass fluororesin substrate at a mounting position of the electronic component excluding an electrode portion is in contact with the glass fluororesin substrate. An electronic component on a glass fluororesin substrate, wherein a solder resist is applied so as to substantially conform to the shape of the solder resist and dried, and an electronic component coated with an adhesive for electronic component bonding is mounted on the upper surface of the solder resist. How to attach. 2. The glass fluororesin substrate according to claim 1, wherein an area of the solder resist applied is larger than an area of an outer shape of a contact portion of the electronic component to the glass fluororesin substrate. How to mount electronic components. 3. The method for mounting an electronic component on a glass fluororesin substrate according to claim 1, wherein the electronic component is a dielectric ceramic component. 4. The electronic component according to claim 1, wherein an automatic mounting machine is used when mounting the electronic component on the glass fluororesin substrate. How to attach. 5. A method according to claim 1, wherein a solder resist is provided at a predetermined position on the surface of the glass fluororesin substrate, and an electronic component is bonded and fixed to the surface of the solder resist via an adhesive. Mounting structure for electronic components. 6. The mounting structure for an electronic component, wherein the glass fluororesin substrate is a substrate for forming a local oscillation circuit of a microwave detector, and the electronic component is a dielectric resonator. .