JP2010028009A - Method for manufacturing metal-resin integrated flat circuit board, and metal-resin integrated flat circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flat circuit board which is inexpensive, the product design of which can be easily changed and which has excellent heat conductivity. <P>SOLUTION: The method for manufacturing a metal-resin integrated flat circuit board includes: a process for manufacturing a lead frame 1 by forming removed portions r obtained by removing a part or all of a metal plate in a thickness direction on the metal plate with a predetermined pattern; and an insert molding process for clamping the lead frame 1 between a surface side metal mold 2 and a rear side metal mold 3 having flat insert contact surfaces 2c, 3c, respectively and in a state that the whole surface and the whole rear face of the lead frame 1 are brought into close contact with the insert contact surfaces 2c, 3c of the surface side metal mold and the rear side metal mold, directly filling the removed portions r with thermosetting resin 5 containing filler, and forming a circuit board 10 having the same thickness as the lead frame 1 and having flat surface and rear face. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technology for manufacturing a metal / resin integrated flat circuit board for mounting a semiconductor chip, a surface-mounted component, or the like.

Conventionally, as a flat circuit substrate on which a semiconductor chip such as a photoelectric conversion element or a surface-mounted component is mounted, a resin substrate typified by glass epoxy is mainly used regardless of a laminated form or a single layer form. This is due to the need for complex rewiring in product specifications. In addition, an inorganic material substrate typified by ceramic may be used for applications that require high reliability.
JP 2007-294743 A

However, a resin substrate typified by glass epoxy has a complicated manufacturing process even if the structure is a single layer, so it is difficult to reduce costs and shorten delivery times. Further, a resin substrate typified by glass epoxy largely depends on the resin characteristics used, and it is very difficult to change these characteristics. In order to achieve this improvement, it is necessary to connect the semiconductor chip mounting pattern and the heat sink placed on the bottom of the substrate via via holes, which increases the number of processes and material costs, further increasing costs and extending the construction period. Connected.
Similarly, an inorganic material substrate typified by ceramic is very superior in physical, mechanical, thermal, and electrical characteristics compared to a resin substrate, but is more expensive than a resin substrate.
Therefore, a main object of the present invention is to provide a flat circuit board which is inexpensive and can be easily changed in product design, and has excellent thermal conductivity.

The present invention that has solved the above problems is as follows.
<Invention of Claim 1>
A step of manufacturing a lead frame by forming a removal portion formed by removing a part or all of the metal plate in the thickness direction with a predetermined pattern;
The lead frame is clamped between a front mold and a back mold each having a flat insert contact surface, and the entire front and back surfaces of the lead frame are inserted into the insert contact surface and the back mold of the front mold. A circuit with flat front and back surfaces having the same thickness as that of the metal lead frame, by directly filling the removal portion with a thermosetting resin containing a filler while being in contact with the insert contact surface of the mold. An insert molding process for forming a substrate;
A method for producing a metal / resin integrated flat circuit board, comprising:

(Function and effect)
With such a manufacturing method, the metal lead frame is inexpensive and requires only a short design and production time, and the molding die is not a special structure and does not need to be dedicated. Become. In addition, since the entire front and back surfaces of the lead frame are molded in contact with the flat contact surfaces of the mold, resin burrs on the lead frame surface are suppressed.
In addition, the combination of the metal lead frame and the resin is a form in which a semiconductor chip is mounted / wired on the metal lead frame and fully molded with a resin as a protection for them, or in recent years after mounting / wiring the semiconductor chip, As an application for potting sealing, there is a form in which a box-shaped package is formed in advance on a metal frame by resin molding, but all are unrelated to the present invention and the idea is completely different.

<Invention of Claim 2>
2. The metal / resin integrated flat circuit according to claim 1, wherein a surface plating process is performed on the manufactured lead frame prior to the insert molding process, and the lead frame is not plated after the insert molding process. A method for manufacturing a substrate.

(Function and effect)
In the present invention, resin burrs are not generated on the surface of the lead frame when the resin is filled by molding the entire front surface and back surface of the lead frame in contact with the flat contact surface of the mold. Therefore, as in the invention described in this section, the post-plating after removing the resin burrs which is difficult and costly is omitted, and the thinning plating is performed at the low-cost metal lead frame manufacturing stage, thereby reducing the manufacturing cost. Can be reduced.

<Invention of Claim 3>
In manufacturing the lead frame, the lead frame is provided with a large number of unit portions to be individual products, and a first resin flow supply removal portion that connects the removal portions of adjacent unit portions is formed. The method for producing a metal / resin-integrated flat circuit board according to claim 1, wherein a second resin flow supply removing portion that is in common communication with each removing portion of the plurality of unit portions is formed.

(Function and effect)
As described above, when the resin flow path is formed in the metal lead frame instead of the mold, the entire lead frame can be optimally filled even when the filling amount of the inorganic filler in the resin is increased.

<Invention of Claim 4>
A metal / resin integrated flat circuit board manufactured by the method according to claim 1.

(Function and effect)
Each effect mentioned above is produced.

  As described above, according to the present invention, there are advantages such as a flat circuit board that is inexpensive, can be easily changed in product design, and has excellent thermal conductivity.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
In the present invention, a lead frame is first manufactured. As the metal flat plate used as the material of the lead frame, a rectangular thin plate having a predetermined size can be used, and the material may be any of Cu (copper) base, Fe (iron) base or other alloys, and the required product characteristics. You can select one that conforms to it. With respect to such a metal flat plate, a part or all of the thickness direction is removed in a predetermined pattern by punching, etching or the like, and a metal lead frame 1 having an arbitrary electrode as shown in FIG. 1 is manufactured. Symbol r is a removal unit. Although this pattern can be determined as appropriate, in the case of mass-produced products, a pattern in which a large number of unit portions 1U that become individual products are arranged in parallel in the vertical and horizontal directions as shown in FIG. 1 is common. .

  When the lead frame 1 is manufactured, a first resin flow supply removal portion r1 that connects between the removal portions r of the adjacent unit portions 1U is formed separately from the removal portions r in the unit portions 1U that are individual products. In addition, it is preferable to form the second resin flow supply removal portion r2 that is in common communication with each removal portion r of the plurality of unit portions 1U, because the resin can be suitably filled to every corner of the lead frame 1. . In a normal case, since the unit portion 1U that becomes an individual product is arranged adjacent to the center portion of the lead frame 1, the second resin flow supply removal portion r2 is arranged around the group of unit portions 1U that become individual products. It is preferable to provide it adjacent to.

  The metal lead frame 1 to be manufactured is preferably in the shape of a rectangular thin plate, and its length and width are the maximum values of the resin molding die and the equipment for assembly using this substrate thereafter. desirable. The thickness of the metal lead frame 1 is preferably 200 μm or more, particularly about 200 to 500 μm in consideration of the resin flow in the removal portion r.

  Next, the manufactured metal lead frame 1 is placed in a mold as an insert, and a molding process is performed. At this time, as shown in FIG. 2, the lead frame 1 is clamped between the front surface side mold 2 and the back surface side mold 3 having flat insert contact surfaces 2 c and 3 c, respectively. The thermosetting resin 5 containing the filler is directly lead from the runner in the mold in a state where the whole is in close contact with the insert contact surface 2c of the front surface side mold 2 and the insert contact surface 3c of the back surface side mold 3. The gap (removal part r) of the frame 1 is filled. At this time, the supplied thermosetting resin 5 is fluidly supplied from the adjacent unit portion 1U to the unit portion 1U via the first resin flow supply removal portion r1, and the second resin fluid supply removal portion. It is distributed and supplied to each removal unit r of a plurality of adjacent unit portions 1U via r2. As a result, as shown in FIGS. 3 and 4, a circuit board 10 having the same thickness as the metal lead frame 1 and a flat front and back surfaces is formed. With such a manufacturing method, the metal lead frame 1 is inexpensive and requires only a short design and production time, and the molding dies 2 and 3 are not special structures and do not need to be dedicated. Easy to change. In addition, since the entire surface and back surface of the lead frame 1 are molded in contact with the flat contact surface of the mold, resin burrs on the surface of the lead frame 1 are suppressed.

  As the thermosetting resin 5 used for molding, any of cross-linked resins can be used. However, in consideration of cost, availability, heat resistance, etc., biphenyl epoxy resin, cresol novolac epoxy resin, A cyclopentadiene type epoxy resin is preferred. An inorganic filler is added and dispersed in the thermosetting resin 5. As the inorganic filler, aluminum hydroxide, calcium carbonate, alumina powder, silica powder, boron nitrite powder, titanium oxide powder, silicon carbide powder, glass fiber, alumina fiber, or the like can be used. It is preferable that the compounding quantity of an inorganic filler shall be 60 to 80 weight% with respect to a thermosetting resin component. When the blending amount of the inorganic filler is less than 60% by weight, the effect of improving the thermal conductivity is poor, and when it exceeds 80% by weight, the resin filling property is lowered. The particle size of the inorganic filler is preferably 20 μm or less.

  The plating process for the lead frame 1 can be performed after the molding process, but is expensive. In the present invention, since a resin burr that conceals the lead frame 1 does not substantially occur, the manufactured lead frame 1 is subjected to a surface plating process prior to the molding process, and the lead frame 1 is plated after the insert molding process. It is preferable not to do so. This plating process is not particularly limited, and general and inexpensive thin-film overall plating such as Ni—Pd—Au and Ni—Au can be used.

  On the other hand, FIG.5 and FIG.6 has shown the utilization example of the board | substrate 10 manufactured with the manufacturing method of this invention, and it is the photoelectric conversion element 11 on the die pad (it is a part formed with the lead frame 1) of the board | substrate 10. FIG. The photodetection chip 20 is shown in which the electrode composed of the lead frame 1 and the photoelectric conversion element 11 are connected by the bonding wire 13 and then sealed with the transparent resin 12. The metal / resin integrated flat circuit board 10 of the present invention can be applied in this manner.

  The present invention is useful as a circuit board having a single layer structure for mounting a semiconductor chip or a surface mount component.

It is the photograph of the sample of a lead frame before shaping | molding. It is ii-ii sectional drawing of FIG. 1 at the time of shaping | molding. It is a photograph of a sample of a lead frame after molding. FIG. 4 is a sectional view taken along line iv-iv in FIG. 3. It is a perspective view of a photon detection chip. It is sectional drawing of a photon detection chip.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Lead frame, 2 ... Front surface side metal mold, 3 ... Back surface side metal mold, 2c, 3c ... Insert contact surface, 5 ... Thermosetting resin, r, r1, r2 ... Removal part, 10 ... Circuit board, 11 ... Photoelectric conversion element, 12 ... transparent resin, 13 ... bonding wire, 20 ... light detection chip.

Claims (4)

A step of manufacturing a lead frame by forming a removal portion formed by removing a part or all of the metal plate in the thickness direction with a predetermined pattern;
The lead frame is clamped between a front mold and a back mold each having a flat insert contact surface, and the entire front and back surfaces of the lead frame are inserted into the insert contact surface and the back mold of the front mold. A circuit with flat front and back surfaces having the same thickness as that of the metal lead frame, by directly filling the removal portion with a thermosetting resin containing a filler while being in contact with the insert contact surface of the mold. An insert molding process for forming a substrate;
A method for producing a metal / resin integrated flat circuit board, comprising:   2. The metal / resin integrated flat circuit according to claim 1, wherein a surface plating process is performed on the manufactured lead frame prior to the insert molding process, and the lead frame is not plated after the insert molding process. A method for manufacturing a substrate.   In manufacturing the lead frame, the lead frame is provided with a large number of unit portions to be individual products, and a first resin flow supply removal portion that connects the removal portions of adjacent unit portions is formed. The method for producing a metal / resin-integrated flat circuit board according to claim 1, wherein a second resin flow supply removing portion that is in common communication with each removing portion of the plurality of unit portions is formed.   A metal / resin integrated flat circuit board manufactured by the method according to claim 1.

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