JPH1174295A - Method for packaging electronic circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for packaging electronic circuit which is suitable for reducing the size and thickness of a package and for increasing the number of electronic circuits to be packaged. SOLUTION: After the space in a molding frame 3 bonded to an integrated circuit board 1 mounted with circuit parts 2 is filled up with a resin 5, an integrated upper plate 12 is put on the frame 3 and the laminated body is diced along cutting lines 6. Since the resin 5 is held between the circuit board 1 and the upper plate 12, no warping occurs, and since the circuit components 2 are convered with the plate 12, the thickness of the resin 2 can be reduced to about the heights of the parts 2. A method in which the circuit board 1, the molding frame 3, and the upper plate 12 are bonded to each other in a box-like state and the resin 5 is injected into the space of the frame 3 or another method, in which plate 12 is put on the parts 2 and the peripheries of the plate, parts 2, and circuit board 1 are sealed with a tape and the resin 5 is injected into the space surrounded by the tape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an integrated circuit (IC) on a circuit board.
The present invention relates to a method of packaging an electronic circuit module in which a small electronic circuit component such as a chip is mounted, a resin is injected, and the circuit component is embedded in the resin.

[0002]

2. Description of the Related Art There are various types of electronic circuits that constitute a module having a certain function by mounting various circuit components on a circuit board. Suitable ones are spreading. FIG. 4 shows a package of such a small circuit, which is conventionally manufactured by the inventors, and has a height of about 10 mm or less and a height of about 5 mm or less, for example.
FIG. 4 (A) shows a cross section taken along line BB of FIG. 4 (B).
A circuit component 103 such as a chip / capacitor is mounted, a mold frame 104 is joined to part or all of the periphery of the circuit board 101, and a resin 105 such as epoxy is injected into the inside of the mold frame 104 to embed the circuit component, and a metal shield is formed. -The case 106 is attached. A window 107 opened in the shield case 106 is a light passage for a photoelectric element in the circuit.

FIG. 4C also shows a package of the same type as the above, and its DD section is shown in FIG.
01 are located on both sides where no resin is loaded. This package also has a metal shield case 106 attached.

In the manufacture of electronic circuits as described above, circuit components are mounted in each area using a collective circuit board in which a large number of areas for electronic circuits are arranged in a matrix in a matrix, and a resin is injected and cured. After that, it is cut off and divided into individual electronic circuits for efficient operation. FIG. 5 shows an example of such a packaging method.

In FIG. 5A, a large number of electronic circuit areas are arranged on a collective circuit board 1, and circuit components 2 are mounted in each area by a chip mounter or the like.
Next, in FIG. 1B, a mold frame 3 of a resin molded product is joined to the circuit component mounting surface of the collective circuit board 1 with an epoxy-based adhesive or the like. The mold frame 3 has many windows 4 corresponding to individual circuit regions, and the circuit components 2 in each region fit in the respective windows. Next, as shown in FIG. 3C, the resin 5 is filled in each window 4 of the mold frame 3. After the resin 5 is cured, dicing is performed to cut the entire length and width along a cutting line 6 which is a boundary of each circuit region as shown in FIG. Each cut part becomes an individual electronic circuit 7,
Complete with a shield case if necessary. This corresponds to the electronic circuit shown in FIGS.

Although the mold frame 3 shown in FIG. 5 has windows 4 provided in a lattice pattern, the windows 4 may be connected in one row or column to form a rectangular window and arranged in parallel. In that case,
The mold frame remains on two parallel sides of the electronic circuit 7 separated in FIG. 5D, and the other two sides have no mold frame and are cut surfaces of the resin.

FIG. 6 shows several cross-sectional views of a state where circuit components are mounted on a collective circuit board and resin is molded. FIG.
(A) is of the packaging method of FIG. FIG.
(B) shows a case in which a mold rib 8 made of resin, resist material or the like is bonded to the collective circuit board 1, which is lower in height than the mold frame 3 in FIG. The area is defined at the root. Such a short mold rib 8 may be peeled off after the resin is cured, and in this case, the electronic circuit is assumed to have a resin-free portion 108 on the substrate as shown in FIG. Become. In FIG. 6C, the resin is molded using a resin molding die 9 without using a mold frame or ribs. After the circuit components are mounted, the mold 9 is brought into contact with the circuit board 1, and the resin 5 is injected into the cavities 10 corresponding to the respective circuit regions, thereby enclosing the circuit components 2. The package by this method does not leave the mold frame in the finished product,
This corresponds to FIGS. 4C and 4D.

[0008]

The above-mentioned electronic circuit packaging method has room for improvement in the following points. That is, as shown in the cross-sectional view of FIG. 6, each of these is a structure in which the resin is placed only on one surface of the integrated circuit board 1, that is, the mounting surface of the components, and the integrated circuit board is shrunk by curing and the like. The substrate 1 tends to warp. FIG. 6 (A),
As shown in FIG. 6B, the mold frame 3 and the mold rib 8 are joined to the collective circuit board 1, or as shown in FIG. The reason why the unfilled part is left is to suppress the warpage of the substrate.
Since the portion without the mold frame and the resin occupies a certain area on the collective circuit board, this is a factor that limits the size reduction of products and the number of products to be manufactured by multi-cavity. However, if the portions without the mold frame and the resin are omitted, the substrate is warped.

Further, in order to prevent the circuit components from being exposed due to resin shrinkage and variations in height, and to protect the circuit components securely in the resin, the thickness of the resin is slightly increased with respect to the height of the circuit components. A margin must be provided, and the reduction in thickness of the product is limited. SUMMARY OF THE INVENTION The present invention solves these problems and provides a method of packaging an electronic circuit that is suitable for miniaturization, thinning, and increasing the number of pieces to be taken.

[0010]

According to a method of packaging an electronic circuit of the present invention, a circuit board on which circuit components are mounted is covered with an upper plate, and a sealing resin is filled between the circuit board and the upper plate and cured to cure. Are integrated. In other words, since the circuit board and the upper plate sandwich the resin layer enclosing the circuit components in a sandwich shape, unlike the conventional case where there is resin only on one side of the circuit board, the warpage of the circuit board is ensured. Can be prevented.

As a specific method, a circuit component is mounted on each circuit area of a collective circuit board for separating into a large number of circuit boards, and a frame-shaped mold frame is adhered around the collective circuit board to form a mold. A resin is poured into the frame, and an assembly upper plate having a size similar to that of the assembly circuit board is placed thereon, and the resin is cured to bond the entire assembly. Then, the package of the electronic circuit is obtained by dicing along the cutting line dividing each circuit region.

As another method, as a mold frame to be adhered to the collective circuit board, a mold frame having three closed sides and one open side, or a mold frame provided with a discontinuous part in one side is provided on the collective circuit board. The top plate of the assembly is adhered thereon to form a box shape, and a resin is injected from an injection port, which is a discontinuous portion of the mold frame, and cured, and diced along a cutting line that divides each circuit region.

In still another method, an assembly upper plate is put on a circuit component mounted on an assembly circuit board in contact with the circuit component. That is, the tallest of the circuit components is used as a spacer for determining the distance between the collective circuit board and the collective upper plate. In this way, the assembly circuit board and the assembly upper plate are stacked, and the periphery is sealed with a sealing tape. However, do not cover the entire area, but leave a part of it open as a resin inlet. Then, a resin is injected from an injection port to be cured, and dicing is performed along a cutting line for dividing each circuit region.

An insulating material is used for the upper plate, or a metal plate is used if the surface of the circuit component is sufficiently insulated and there is no danger of short circuit. A metal plate coated with insulation may be used, or a metal layer may be overlaid on the upper plate of the insulating material.By providing such a metal plate or metal layer, a shielding function can be obtained, and a shield case as in the past can be obtained. The reliability is maintained without the use of.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of a method for packaging an electronic circuit according to the present invention. In FIG. 1 (A), reference numeral 1 denotes a collective circuit board, which includes a large number of regions serving as substrates for individual electronic circuits, and a circuit component 2 is mounted in each region by a chip mounter. Reference numeral 3 denotes a resin-made frame having a frame shape, which is bonded to the collective circuit board 1 with an adhesive. Next, in FIG. 2B, a resin 5 is injected into the inside of the mold frame 3 to enclose the circuit components in the resin 5. Next, in FIG. 3 (C), the assembly upper plate 12 is attached to the mold frame 3 with an adhesive.
Then, the resin 5 is cured and the collective circuit board 1, the mold frame 3, and the collective upper plate 12 are joined together. When this is diced along a cutting line 6 which is a boundary line of each circuit region as shown in FIG.
A large number of packaged electronic circuits 7 are taken.
The mold frame 3 may have a thickness equal to or slightly larger than the tallest of the circuit components.

FIG. 2 shows a second embodiment of the present invention. First, as shown in FIG. 1A, the collective circuit board 1 on which the circuit components 2 are mounted, the mold frame 3, and the collective upper plate 12 are integrally joined with an adhesive. In this embodiment, the mold frame 3 is 4
A closed side is used instead of a closed side. The left side of FIG. 2 (B) is a state in which the box-shaped joint is set up, and the portion where the mold frame 3 is opened on the upper side is the resin injection port 13. The mold frame 3 may not be entirely removed, but may be provided with a discontinuous portion at a part of the upper side as the injection port 13 as shown on the right side of FIG. The resin 5 is injected from the injection port 13 as shown in FIG. If the resin 5 is cured and diced along the cutting line 6, a large number of electronic circuit packages can be obtained.

FIG. 3 shows a third embodiment of the present invention. In this method, a mold frame is not used as in the above two embodiments. In FIG. 1A, an assembly upper plate 12 is superimposed on the circuit component 2 mounted on the assembly circuit board 1. FIG. 7A shows the state when viewed from the side.
Has a lower surface in contact with the tallest one of the circuit components 2, and the circuit component 2 is connected to the collective circuit board 1 and the collective upper plate 12.
It is used as a spacer to determine the distance between the two. Wire-bonded IC chips are not suitable for spacers, but electronic circuits typically include taller circuit components. Next, as shown in FIG. 3B, the periphery of the assembled circuit board 1 and the assembled upper plate 12 thus overlapped with each other is
Is sealed with a sealing tape 14 such as an adhesive tape.
As shown in FIG. 2C, the resin 5 is injected from the injection port 13 to fill the inside, the resin 5 is cured, the sealing tape 14 is peeled off, and dicing is performed along the cutting line 6.

If the upper plate 12 is made of an insulating material, the lower surface thereof can be brought into contact with the circuit component 2 without causing a short circuit. In order to make the product thinner, a material as thin as possible (for example, about 0.1 mm) is used as far as the strength allows. Depending on the function of the module, photo-transistors, photo-diodes, LEDs and other light-receiving and light-emitting photoelectric elements are included.
In this case, the upper assembly plate 12 needs to transmit light, and a transparent or translucent resin material or the like is used depending on the intensity of the light.
However, if there is a circuit component that requires light shielding on the other side, that portion is subjected to mask printing or the like on the assembly upper plate 12.

If the surface of the circuit component 2 is sufficiently insulative, the collecting upper plate 12 can be made of a metal plate, and a shielding action can be obtained from the metal upper plate. In order to connect the metal upper plate to the ground pattern of the circuit board to stabilize the shielding action, for example, a spring piece for grounding or a conductive elastomer may be placed on the ground pattern and brought into contact with the lower surface of the upper plate. Can take structure. The metal upper plate has an advantage of being excellent in light-shielding properties and heat dissipation properties in addition to the shielding effect. The lower surface of the metal upper plate may be brought into contact with the circuit component by applying insulation coating or the like. In order to ground the metal upper plate, a part of the insulating coating on the lower surface is omitted, and the grounding spring piece or the like is brought into contact with the insulating cover.

Although the embodiments of the present invention have been described above, the mold frame 3 and the sealing tape 14 as seen in these embodiments have been described.
The method of the present invention can also be performed using a jig or a fixture without using the method. Although details are omitted, for example, in the case of the method of FIG. 1, instead of joining the mold frame 3 to provide a wall for resin injection around the collective circuit board 1, a box-shaped jig having a wall around it is used. A method may be used in which the collective circuit board 1 is placed inside, resin is injected, and the collective upper plate 12 is placed thereon. Or Figure 2
In the case of the method of FIG. 3 or FIG. 3, the peripheral circuit is closed by attaching the collective circuit board 1 and the collective upper plate 12 to a jig having a U-shape with an open top, and resin is injected from the opening and cured. May be. If the width of the jig is increased, a number of sets of the collective circuit board 1 and the collective upper plate 12 can be mounted in parallel on one jig, so that the circuit can be packaged efficiently. Such methods are also within the scope of the present invention.

[0021]

According to the electronic circuit packaging method of the present invention, since the resin is sandwiched between the circuit board and the upper plate,
In a manufacturing method using a large collective circuit board having a large area for taking a large number of electronic circuits, it is possible to prevent warpage of the board,
Processing accuracy and yield are improved. The electronic circuit completed by dicing has a resin surface around it and does not include a mold frame, and there is no substrate area on which resin is not mounted. Therefore, the area of the product can be reduced, and the electronic circuit can be obtained from one integrated circuit board. The number increases and the manufacturing cost decreases. Since the electronic circuit is protected by the upper plate, it is possible to use a soft resin that could not be used before, increasing productivity, and selecting the optimal resin according to the application and atmosphere of the electronic circuit To increase the reliability of the product. Since the distance between the circuit board and the upper plate is determined by using the mold frame and the circuit components as spacers, there is no variation in the height of the product, and the thickness of the package can be reduced. Further, since the upper surface of the product is formed of a flat upper plate, mounting by the mounter can be ensured. Therefore, mounting on an electronic device becomes easy. As described above, the method of packaging an electronic circuit according to the present invention enables the improvement of the productivity of the electronic circuit and the miniaturization and thinning of the electronic circuit, thereby contributing to the cost reduction and miniaturization of the electronic device using such a circuit.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a procedure of an embodiment of an electronic circuit packaging method according to the present invention.

FIG. 2 is a perspective view showing a procedure of another embodiment of the electronic circuit packaging method of the present invention.

FIG. 3 is a perspective view showing a procedure of still another embodiment of the electronic circuit packaging method of the present invention.

FIG. 4 shows a conventional electronic circuit package, as shown in FIG.
(C) is an external view, and FIGS. (B) and (D) are a BB sectional view and a DD sectional view of FIGS. (A) and (C), respectively.

FIG. 5 is a perspective view showing a procedure of a conventional electronic circuit packaging method.

FIG. 6 is a cross-sectional view showing a state in which a resin is molded on a collective circuit board on which circuit components are mounted in a conventional electronic circuit packaging method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Assembly circuit board 2, 103 Circuit component 3, 104 Mold frame 5, 105 Resin 6 Cutting line 7 Electronic circuit 8 Mold rib 9 Die 12 Assembly upper plate 13 Injection 14 Sealing tape 101 Circuit board 102 IC chip 106 Shield ·Case

Claims (5)

[Claims] 1. A circuit component is mounted on each of a plurality of circuit regions provided on a collective circuit board, a resin is injected into the inside of a wall surrounding the collective circuit board, and a collective upper plate is placed thereon. After the resin is cured and the integrated circuit board, the resin layer, and the upper board are integrated, the circuit board is cut into individual circuit regions to enclose the circuit components in the resin and obtain a structure in which the circuit board and the upper board are sandwiched. How to package the circuit. 2. The method of packaging an electronic circuit according to claim 1, wherein a wall surrounding the periphery of the collective circuit board is provided by bonding a frame-shaped mold frame to the collective circuit board. 3. A circuit component is mounted on each of a plurality of circuit areas provided on the collective circuit board, and the collective circuit board and the collective circuit board are disposed in contact with or at a slight distance from the circuit component. After sealing the periphery, leaving the resin injection port, injecting the resin from the injection port and curing it to integrate the collective circuit board, resin layer, and collective upper plate, and then cutting this for each circuit area A method of packaging an electronic circuit in which components are encapsulated in resin to obtain a structure sandwiched between a circuit board and an upper plate. 4. The method of packaging an electronic circuit according to claim 3, wherein sealing around the collective circuit board and the collective upper plate is performed by sandwiching a mold frame having an injection port therebetween. Electronic circuit packaging method. 5. The method for packaging an electronic circuit according to claim 3, wherein the sealing around the collective circuit board and the collective upper board is performed by bringing the collective upper board into contact with a circuit component. A method of packaging an electronic circuit by defining an interval between the two and sealing the periphery with a tape material leaving an injection port.