JPH07161873A - Hybrid ic and its manufacture - Google Patents

Abstract

PURPOSE:To prevent the bridge by solder for mounting parts from occurring between the mounted parts or circuit wirings inside a hybrid IC, in the solder reflow processing at the time of soldering the hybrid IC to a device board, concerning the resin covering structure of the hybrid IC. CONSTITUTION:In a hybrid IC of which the surface of the hybrid board where surface-mount type of parts 2A and 2B are mounted using solder 5 is covered with resin, the cover resin film 6 is provided with solder niches 8A1, 8A2, 8B1, and 8B2 whose bottoms contact with the topside of the parts mounting solder 5 soldering the mounted parts 2A and 2B and whose tops open to the surface of the cover rein film 6, or space for solder relief is provided selectively between the parts mounting solder 5 and the cover resin film 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hybrid IC and a method of manufacturing the same, and more particularly to a hybrid IC in which a surface-protecting resin coating is applied to the surface of a printed circuit board on which surface-mounted components are solder-mounted and a method of manufacturing the same.

In recent years, hybrid ICs are required to be mounted by a customer at a high temperature using a solder reflow furnace in order to improve the mounting efficiency when mounted on a device substrate.

Therefore, in the above hybrid IC,
During the solder reflow process at the time of mounting on the above-mentioned device substrate, in order to prevent the mounting components from moving or peeling due to melting of the solder used for mounting the components inside the IC, the surface of the hybrid substrate on which the components are mounted is A structure is used in which the mounting resin is directly covered with a coating resin and the mounting force of the coating resin film prevents the mounting component from moving or peeling.

However, in this structure as well, the solder for mounting the component, which is melted by the high temperature during the reflow, flows in the lateral direction through the insufficiently adhered portion or the fragile portion of the coating resin, thereby adjoining the adjacent component or circuit. Since the problem of short-circuiting between wirings occurs, improvement is desired.

[0005]

2. Description of the Related Art A hybrid IC in which surface mounting type mounting components are mounted by soldering is schematically shown on a printed wiring board 51 having a predetermined circuit wiring 52, as shown in a schematic sectional view of FIG. Electrode pad connected to the circuit wiring
By soldering 53 and the electrode terminal 54 with the component mounting solder 55A, the FET 56, the resistor 57, the capacitor 58, etc. are connected and mounted, and the printed wiring board 51 on which this component is mounted 51
However, by fixing the lower surface on which a conductive film (not shown) is formed with the same component mounting solder 55B as described above, it is fixedly housed in the metal heat dissipation container 59 while maintaining low thermal resistance, and the above component mounting is performed. After the printed wiring board 51 is covered with a thick coating resin film 60 made of silicon resin or the like for the purpose of holding the mounted components and protecting the surface, a metal cap (not shown) is put on the heat dissipation container 59. Was configured.

Hybrid IC having such a configuration
Printed wiring board on which components have been mounted in the past
The coating resin film 60, which is formed for the purpose of fixing the mounted components and protecting the surface of the mounted components, covers the printed wiring board 51 on which the components are mounted, and the liquid coating resin is mounted on the printed wiring substrate 51 as it is. It is formed by pouring to a filling thickness and applying it, and then heating it to a predetermined curing condition to cure and solidify the liquid resin, so that the solidified coating resin film 60 is mounted components 56, 57, Display surface of 58, etc., component mounting solder that adheres these components
It was formed along the entire exposed surface of 54A and the exposed surface of the printed wiring board 51, and was directly attached.

[0007]

As described above, in the conventional hybrid IC, the coating resin film 60 covering the printed wiring board on which the components are mounted has the mounting components 56,
57, 58, etc. and the component mounting solder 54A and the printed wiring board 51 should be formed by directly adhering to the entire exposed surface of the printed wiring board 51. In particular, it should be formed by directly adhering to the entire exposed surface of the component mounting solder 54A. This caused the following problems.

That is, as described above, the melting temperature of the component mounting solder used for connecting and fixing the component on the printed wiring board is low in consideration of the low heat resistance guarantee temperature of the component.
Ordinary solder with a temperature of 230 to 240 ° C is used, but in the solder reflow process in the reflow furnace when mounting this hybrid IC on the device substrate, the low melting point solder is not used to secure the connection reliability. The same solder paste as normal solder is used.

Therefore, during the solder reflow process for mounting the hybrid IC on the device substrate, the component mounting solder 55A to which the mounted components in the hybrid IC are welded is also completely melted and expanded.

Then, as shown in FIG. 6, the melted and expanded component mounting solder 55A peels off the adhesive surface between the printed wiring board 51 and the coating resin film 60, which have a weak adhesion. Peeling portion), or a defective portion (not shown) of the coating resin 60 weakened by the presence of air bubbles or the like, so that the solder 55A flows out from the peeling portion 61 or the defective portion (not shown), The problem is that the parts to be connected, such as 58A and 58B, or adjacent circuit wirings (not shown) are bridged to short-circuit adjacent parts or circuit wirings. (In the figure, 53A, 53B, 53C, 53D are electrode pads,
54A ₁ , 54A ₂ , 54B ₁ and 54B ₂ are the electrode terminals of the mounted components) It is possible to improve this problem to some extent by using a higher temperature solder than the reflow solder for the component mounting solder. As described above, since the heat-resistant guaranteed temperature of the mounted components is low, the yield and reliability of the hybrid IC are deteriorated, which is not preferable.

Therefore, according to the present invention, in the solder reflow process for mounting the hybrid IC on the device substrate, even when the solder used for mounting the components in the hybrid IC is melted and expanded, the adjacent components are adjacent to each other or adjacent to each other. An object of the present invention is to provide a structure and a method for forming a coating resin film on a hybrid IC that does not generate a solder bridge between circuit wirings.

[0012]

To solve the above-mentioned problems, a hybrid IC in which a resin is directly coated on the surface of a hybrid substrate on which surface mount type components are mounted using solder.
In the hybrid according to the present invention, the coating resin film is provided with a solder withdrawal hole whose lower end is in contact with a component mounting solder for soldering the mounting component and whose upper end is open to the surface of the coating resin film. In a hybrid IC in which an IC or a surface mount type component is directly resin-coated on the surface of a hybrid substrate mounted using solder, the component mounting solder and the coating resin film for soldering the mounted component When a hybrid IC according to the present invention in which a clearance for solder evacuation is selectively provided between or, and when a surface of a hybrid substrate on which a surface mount type component is mounted by soldering is covered with a resin film, The substrate is prepared by pouring a resin for coating onto the substrate with the tip of the pin in contact with the surface of the component mounting solder that is soldering the component to the substrate from above. With a resin film, and then solidifying the resin film, and then pulling out the pins to form solder retreat holes reaching from the solder for mounting the component to the resin film to the surface of the resin film. Hybrid IC according to the invention
In the method of manufacturing the same or when the entire surface of the hybrid substrate on which the surface mount type component is mounted by soldering is coated with a resin film, a resin for coating is poured on the substrate and the resin is coated on the substrate. After covering with a film, the resin film is solidified in a state in which the substrate is heated to a temperature near the melting point of the solder where the solder can maintain a solid state, and then the substrate is returned to room temperature to This can be achieved by the method for manufacturing a hybrid IC according to the present invention, which has a step of selectively forming a clearance for retreating the solder between the solder for mounting the component and the resin film.

[0013]

1 and 2 are sectional views for explaining the principle of the present invention. According to the first aspect of the present invention, as shown in FIG. 1 (a), a mounting component 2 including an FET, a resistor, a capacitor, etc.
(2A, 2B, etc.) have their electrode terminals 3 (3A ₁ , 3A ₂ and
3B ₁ , 3B ₂ ), etc. on the electrode pad 4 on the hybrid substrate 1
(4A ₁ , 4A ₂ and 4B ₁ , 4B ₂ etc.) is covered with the component mounting solder 5, and the covering resin film 6 is formed thickly to cover the entire surface of the mounted hybrid substrate 1
In addition, the lower end portion is in contact with the component mounting solder 5 for soldering the component 2 (2A, 2B, etc.), and the upper end portion is a solder retraction hole 8 (8A ₁ , 8A ₂ and 8B) opened on the surface of the coating resin film 6. ₁ , 8B ₂ ) etc. are provided.

By doing this, the high
Solder remounting when mounting the Brid IC on the device substrate
The part in the hybrid IC that melts and expands during flow
As shown in Fig. 1 (b), the product mounting solder 5 is the solder
Evacuation hole 8 (8A₁, 8A₂And 8B ₁, 8B₂Etc.) overflows into
Therefore, the melted and expanded solder 5 exerts stress on the coating resin film 6.
This will prevent blistering, avoiding peeling and cracks.
The solder for mounting the component 5 does not flow into the peeling portion or the crack portion from
Prevents solder bridges between adjacent components or adjacent circuit wiring.
Be stopped.

Further, in the second invention according to the present invention, FIG.
As shown in (a), the components 2 (2A, 2B, etc.) of the coating resin film 6 formed thickly covering the entire surface of the hybrid substrate 1 on which the components 2 (2A, 2B, etc.) are mounted in the same manner as described above. ) Is soldered on the hybrid board 1 for component mounting 5
A solder escape gap 9 is selectively provided in a region in contact with the exposed surface of the.

By doing so, the component mounting solder 5 in the hybrid IC that is melted and expanded during solder reflow when the hybrid IC is mounted on the device substrate later is as shown in FIG. 2 (b). In addition, since the solder 5 is housed in the solder evacuation gap 9, the stress exerted by the melt-expanded solder 5 on the coating resin film 6 is reduced, and the coating insulating film 6 may be peeled or cracked by the stress. By avoiding, the solder bridge between adjacent components or adjacent circuit wiring due to the component mounting solder 5 is prevented as in the first aspect of the invention.

[0017]

EXAMPLES The present invention will be described in detail below with reference to the drawings by the examples of the manufacturing method. 3 is a process sectional view of an embodiment of the method of the present invention, and FIG. 4 is a process sectional view of another embodiment of the method of the present invention. Note that the same object is denoted by the same reference numeral throughout the drawings.

Referring to FIG. 3 (a), in forming the hybrid IC having the coating resin film having the structure according to the first invention,
Printed wiring board (hybrid board) 1
Electrode pads 4A ₁ of the surface, 4A _2, and 4B _1, 4B on the _two equal, such as tin 60: using conventional solder having 230-240 ° C. of about the melting point having a composition of lead 40 to solder the component mounting, By the solder reflow means, the electrode terminals 3A ₁ , 3A ₂ , and 3B
_1, the 3B _2, etc. Each component mounting solder 5A _1, 5A _2, and 5B _1, by soldering by 5B ₂ or the like, FET on the hybrid substrate 1, the resistance, mounting parts 2A made of either such a capacitor , 2B etc. are connected and fixed, and then the lower end (tip) is first placed on the component mounting solders 5A ₁ , 5A ₂ and 5B ₁ , 5B ₂ etc. to which the above-mentioned components 2A, 2B etc. are fixed. The pins 11A ₁ and 11A ₂ and 11B ₁ and 11B _{2 and the} like are pressed and held from above so as to directly contact each other. Note at this time, pin 11A _1, 11A _2, and 11B _1, component mounting solder 5A ₁ on 11B ₂ arrangement such as the pre-hybrid substrate 1, 5A _2, and 5B
₁ , 5B ₂ etc. are defined according to the position, and by inserting a coil spring or the like on the upper part of each pin, movement in the height direction is made possible and contact is ensured.

Referring to FIG. 3 (b), the component mounting solders 5A ₁ , 5A ₂ and 5B are then mounted as described above.
_1, pin 11A ₁ on 5B _2, etc., 11A _2, and 11B _1, 11B ₂ and the like in a state of pressure contact, over the entire surface of the hybrid substrate 1, the note under unit, thermoset having a liquid The coating resin layer such as the silicon resin layer 106 is applied and formed to a thickness of, for example, about 10 to 30 μm, which is sufficient for fixing and protecting the mounting components 2A, 2B and the like.

See FIG. 3 (c). Then, for example, room temperature / 1 hour, 70-80 ° C./1 hour, 140
The silicone resin layer 106 is solidified by performing a step cure such as ℃ / 1 hour to form the coating resin film 6 made of silicone resin, and then the pins 11A ₁ , 11A ₂ and 11B ₁ , 11 are formed.
B ₂ etc. is pulled out upward, the lower end directly contacts the component mounting solder 5A ₁ , 5A ₂ , and 5B ₁ , 5B _2, etc. on the coating resin film 6 and the upper end opens on the surface of the coating resin 6. Solder evacuation hole 8A
₁ , 8A ₂ , and 8B ₁ , 8B _2, etc. are formed. Here,
If the release agent is thinly applied to the surfaces of the pins 11A ₁ and 11A ₂ and 11B ₁ and 11B ₂ , the pins can be easily pulled out after the resin film 6 is cured.

The first aspect of the present invention formed by the above steps
The coating resin film 6 of the hybrid IC according to the invention of FIG.
As shown in (c), the mounting components 2A, 2B, etc. are attached to the coating resin film by electrode pads 4A ₁ , 4A ₂ on the hybrid substrate 1, and
Component mounting solder 5A ₁ , which is soldered on 4B ₁ , 4B _2, etc.
5A ₂ and 5B ₁ , 5B ₂ etc. have their lower ends in contact with each other, and their upper ends open to the surface of the coating resin film 6 solder retreat holes 8A ₁ , 8
The structure has A ₂ , and 8B ₁ and 8B ₂ . Therefore,
250 when mounting the hybrid IC on the device substrate
In solder reflow process at high temperature up to 260 ℃, IC
Even when the internal component mounting solder melts and expands, the expanded part of the solder overflows into the solder evacuation hole formed in contact with the solder (see FIG. 1 (b)). The membrane is no longer stressed. Therefore, due to the peeling of the coating resin film from the substrate and the cracking of the coating resin film itself, which has conventionally occurred due to the stress of the expanded solder, and the flow of the component mounting solder to the peeling portion and the crack portion with it. Solder bridges between adjacent components or between adjacent circuit wiring are prevented.

See FIG. 4 (a). Also, the coating of the structure according to the second aspect of the present invention (coating
When forming a hybrid IC having a resin film
In the same way as before, the printed wiring board (hybrid
Substrate) 1 surface electrode pad 4A₁, 4A₂, And 4B₁, 4B
₂Etc., using solder reflow means, the electrode terminal 3A₁,
3A₂, And 3B₁, 3B₂5A each for component mounting solder₁,
5A₂, And 5B₁, 5B₂By soldering with
, FET, resistor, capacitor, etc.
After connecting and fixing parts 2A, 2B, etc., this hybrid board
1. On the entire surface of 1, by the pouring means, for example, as in the above embodiment
The liquid silicone resin layer is used to mount components 2A, 2B, etc.
Thick enough to set and protect, eg about 10-30 μm
And then apply it to the silicon at a temperature of 70-80 ℃.
The solvent contained in the resin layer is removed by drying, and the hive is then removed.
The lid substrate 1 is a semi-mountable component mounting solder that can maintain a solid state.
Maintained at a temperature close to the melting point of the rice field, for example, 200 to 220 ℃
Placed on the heated heater 12, the silicon resin
The layers are cured and the hybrids with components 2A, 2B, etc. mounted are mounted.
A silicon resin film 6 for covering the surface of the printed circuit board 1
To do. Note that the component mounting solder 5A in this figure₁, 5A₂,
And 5B ₁, 5B₂Etc. show the expanded state at the above temperature
ing.

Next, referring to FIG. 4 (b), the hybrid substrate 1 is cooled to room temperature. 5A of component mounting solder that had expanded due to this cooling to room temperature
₁ , 5A ₂ , 5B ₁ , 5B ₂ etc. contracted and melted and expanded between these component mounting solders 5A ₁ , 5A ₂ and 5B ₁ , 5B ₂ etc. and the silicon resin film 6 covering the upper part thereof. Solder escape gap 9A ₁ , large enough to accommodate most of the component mounting solder,
9A ₂ , 9B ₁ , 9B _2, etc. are formed.

The second aspect of the present invention formed by the above steps
The coating resin film 6 of the hybrid IC according to the invention of FIG.
As shown in (b), component mounting solder 5A₁, 5A₂, And 5
B₁, 5B ₂Parts that have been melt-expanded between the etc. and the coating resin film 6
Solder evacuation gap 9A that can accommodate most of the mounted solder₁,
9A₂, And 9B₁, 9B₂And so on. Therefore,
250 when mounting the hybrid IC on the device board
In solder reflow process at high temperature up to 260 ℃, IC
Even when the internal component mounting solder melts and expands, the solder
Gap 9A₁, 9A₂, And 9B₁, 9B₂Fills the inside etc. and expands
Therefore, the expansion solder is applied to the coating resin film 6.
The force is significantly reduced compared to the conventional case, and
Similarly, the coating that was previously caused by the stress of expanded solder
Peeling of the resin film from the substrate or cracking of the coated resin film itself
Parts mounting on the raw part and the peeling part and crack part accompanying it
Wiring between adjacent components due to solder flow or adjacent circuit wiring
Solder bridges between them are prevented.

[0025]

As described above, in the hybrid IC according to the present invention, the component mounting solder inside the hybrid IC melts during the high temperature solder reflow process when the hybrid IC is mounted on the device substrate. It is possible to prevent a short circuit due to a solder bridge such as between the mounted components or between the circuit wirings.

Therefore, according to the present invention, a hybrid IC
It is possible to raise the solder reflow temperature when mounting the IC on the device substrate and improve the mounting efficiency, and at the same time, improve the yield and reliability of mounting the hybrid IC on the device substrate.

[Brief description of drawings]

FIG. 1 is a sectional view for explaining the principle of the present invention (No. 1)

FIG. 2 is a sectional view for explaining the principle of the present invention (No. 2)

FIG. 3 is a process sectional view of an embodiment of the method of the present invention.

FIG. 4 is a process sectional view of another embodiment of the method of the present invention.

FIG. 5 is a schematic cross-sectional view of a conventional hybrid IC

FIG. 6 is a schematic cross-sectional view showing a conventional problem

[Explanation of symbols]

1 Hybrid board 2A, 2B Mounted component 3A ₁ , 3A ₂ , 3B ₁ , 3B ₂ Electrode terminal 4A ₁ , 4A ₂ , 4B ₁ , 4B ₂ Electrode pad 5, 5A ₁ , 5A ₂ , 5B ₁ , 5B ₂ Component mounted solder 6 Covering resin film (silicon resin film) 7A ₁ , 7A ₂ , 7B ₁ , 7B ₂ Soldering part 8A ₁ , 8A ₂ , 8B ₁ , 8B ₂ Solder retraction hole 9, 9A ₁ , 9A ₂ , 9B ₁ , 9B ₂ Solder escape gap 11A ₁ , 11A ₂ , 11B ₁ , 11B ₂ pin 12 Heater 106 Liquid silicone resin layer

Claims (4)

[Claims] 1. A hybrid IC in which a resin is directly coated on the surface of a hybrid substrate (1) on which a surface mount type component (2) is mounted using solder (5).
In (6), the lower end is in contact with the component mounting solder (5) to which the mounting component (2) is soldered, and the upper end is a solder withdrawal hole (8) opened on the surface of the coating resin film (6). A hybrid IC characterized by being provided with. 2. A hybrid IC in which a resin is directly coated on the surface of a hybrid board (1) on which a surface mount type component (2) is mounted using solder (5).
A hybrid IC characterized in that a clearance (9) for solder retraction is selectively provided between the component mounting solder (5) to which (2) is soldered and the coating resin film (6). . 3. When covering the entire surface of a hybrid board on which a surface mount type component is mounted by soldering with a resin film, a pin is formed on the surface of the component mounting solder that is soldering the component to the board. A resin for coating is poured onto the substrate with the tip portion in contact with the substrate from above, the substrate is covered with the resin film, and then the resin film is solidified, and then the pin is pulled out to remove the resin film. A method of manufacturing a hybrid IC, comprising the step of forming a solder withdrawal hole that reaches the surface of the resin film from above the solder on which the component is mounted. 4. When covering the entire surface of a hybrid substrate on which a surface mount type component is mounted by soldering with a resin film, a resin for coating is poured on the substrate to form the resin film on the substrate. , The resin film is solidified in a state in which the substrate is heated to a temperature in the vicinity of the melting point of the solder that can maintain the solid state of the solder, and then the substrate is returned to room temperature to remove the component. A method of manufacturing a hybrid IC, comprising a step of selectively forming a clearance for retreating the solder between the solder for mounting the solder and the resin film.