JPS5953700B2 - Implementation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Electronic devices such as radios, televisions, and audio tape recorders are becoming smaller and thinner.

For this reason, the electronic components that make up these electronic devices have changed from solid resistors with lead wires at both ends to chip resistors, which have a resistor layer printed on a ceramic substrate several millimeters square. It was. Furthermore, capacitors also changed to chip capacitors, which were made by laminating electrolytic layers several millimeters square. Furthermore, in the packaging of ICs, flat pack type packages, which are thinner and smaller, have come to be used instead of DIL type packages. Electronic devices are gradually becoming smaller and thinner through mounting using these smaller and thinner electronic components, but as the number of ICs mounted has increased in recent years, the method of mounting the ICs has become problematic. has been looked at.

The IC itself has circuit functions built into a Si chip using semiconductor technology, and the size of the Si chip is the actual size of the IC. The size of this IC (for example, a Si chip) makes it extremely difficult to handle when mounted on a printed circuit board, etc., so the electrode terminals provided on the Si chip were enlarged and D
IL type and flat pack type are used. However, for this reason, the mounting area becomes significantly larger than that of the Si chip. For example, a 5mm square LSI with about 60 pins
In this case, when packaged in a flat pack type, the mounting area is 22 x 22 mm, which is about 20 times that of a Si chip, and as the number of ICs mounted increases, the mounting area of electronic devices increases. It's going to happen. The present invention is an IC
The purpose is to mount electronic components such as chip resistors, chip capacitors, etc. in a high-density and thin manner.

FIG. 1 illustrates a conventional mounting method that is considered to have relatively high density.

In FIG. 1, the details will be mainly focused on the implementation of the IC. Thickness 1
A wiring body 2 of Au, Ag or silver/palladium is formed on a ceramic substrate 1 of ~3 mm by screen printing (FIG. 1a).

Next, a Cu layer 3 is formed (FIG. 1b). The Cu layer 3
is formed to a thickness of several 10 to several 100 μm by resistive heating, vacuum evaporation methods such as sputtering, or electroplating methods. A pattern 3' having an arbitrary shape is formed on the Cu layer 3 by photolithography (FIG. 1c). Next, the IC chip 4 having the electrode terminals 5 is fixed onto the ceramic substrate 1 with a conductive adhesive or the like (FIG. 1d). A polyimide resin layer 6 is provided on the ceramic substrate on which the Cu pattern 3'' and the IC chip 4 are mounted (FIG. 1e).The formation of the polyimide resin layer 6 involves the formation of a polyimide resin film that is thicker than the 1C chip. The structure shown in Fig. 1e may be obtained by applying heat and pressure from above the 1C chip, or alternatively, it may be formed by spin coating a liquid polyimide resin. Chip 4 electrode terminal 5
The polyimide resin 6 on top and Cu pattern 3″
The holes are opened to form the openings 7 and 8 (FIG. 1f).

The openings 7 and 8 can be formed by a photoetching method in which a photosensitive resin is applied onto the polyimide resin 6. A Cr-Cu film is deposited by vapor deposition on the surface where the openings 7 and 8 are formed, and a wiring pattern 9 is formed by photoetching to connect the openings 7 and 8. Obtain the structure shown in Figure 1g.

Since the IC chips are mounted in the chip state, high-density packaging can be achieved, but there are the following drawbacks. 10,000,
If the IC chip is defective, the 1C chip cannot be replaced.

2. The number of process steps required to obtain the structure shown in FIG. 1g is too large, resulting in a decrease in yield.

3. Furthermore, since the thickness of the ceramic substrate is required, the thickness of the mounted body increases.

The present invention aims to eliminate these conventional drawbacks.

The invention is explained in detail in FIG. This metal plate (e.g. 0
．． 1-0.3mm Ni plate) 40 in advance.
Openings 41, 4'' into which chip parts are inserted are formed by punching or photoetching (FIG. 2a).Next, one side of the metal plate 40 or a metal film (for example, 5 to 3
An adhesive 43 is applied to one side of the Cu plate (Cu plate) 42 having a thickness of about 5 μm, and the metal plate 40 and the metal film 42 are bonded together (FIG. 2b). A photosensitive resin is applied onto the metal film 42, irradiated with ultraviolet rays using a mask with a desired lead wiring pattern formed thereon, developed, and further the metal film 42 is chemically etched, as shown in FIG. 2C. Lead wiring 42'' is formed as shown in FIG.
``If you apply photosensitive resin to the metal film on the side,
During chemical etching of the lead wiring pattern, the openings 41, 4
It is possible to prevent etching from progressing from the 1" side. If a positive photosensitive resin with a relatively high resolution of 7 (for example, AZ-1350J manufactured by Shipley) is used as the photosensitive resin, it is possible to prevent etching from progressing from the 1" side. The photosensitive resin can be easily removed using an organic solvent such as acetone.Furthermore, if the metal film is a Cu film, a ferric chloride solvent is suitable as the etching solution. solder bumps etc. 44,
Insert an IC 45'' having a diameter of 44'' and a chip component 45 into the openings 41, 41'' of the metal plate 46, align the solder bumps etc. 44, 44'' and the lead wiring 42'',
The heated jigs 20, 2'' (temperature 300 to 400°C) apply pressure 21, 21''. Through this operation, the solder bumps 44, 44'' and the lead wiring 42'' are soldered and fixed. (Fig. 2 d).Finally, a protective film 22, 22'' of epoxy resin or silicone resin is applied and cured to obtain the structure shown in Fig. 2 e. Further, in the case of the present invention, crossover wiring can be implemented using the above-mentioned Ni board. This will be explained in FIG. A metal film is bonded to only the portions corresponding to 90 and 9'' in FIG. 3 on the Ni plate having predetermined openings without applying adhesive. That is, the adhesive 43 is applied by screen printing using a mask material. After that, when the formation of the lead wiring pattern is completed, the lead wiring 5
By soldering and fixing 42'' and 42'' on the Ni plate 4', the lead wirings 42'' and 42'' can be electrically connected by the Ni plate 4'. In the present invention, the Ni plate is FesBs. Has conductivity such as SuS,
The Ni plate is not limited to the Ni plate as long as it has mechanical strength, and the Ni plate serves as the base of the package in the final completion process and mechanically reinforces the package. Moreover, the metal film is Cu. Bs. It can also be made of metal such as Al. FIG. 4 is a plan view of FIG. 2.

ICl8 and chip parts 1 are placed on the Ni plate 11 in advance.
It has an opening 12 for inserting the holder 7. Said Ni
Lead wires 13'' are formed on the plate 11 via an adhesive layer 14.The lead wires 13'' are located at positions corresponding to the electrode terminals of the IC 8 and chip component 17 inserted in the opening 12. This is a structure in which the wiring extends up to the opening 12, and is further formed to cross the opening 12, like the lead wiring 13''''. The lead wires extending into the openings 12 are connected to bumps 19 on the electrode terminals of the ICl 8 and bumps 16 on the electrode terminals of the chip component 17.
Further, a base for increasing mechanical strength is integrally formed on the opposite surface of the Ni plate 11 on which the lead wiring 13'' is not formed, and a circuit group formed on the base is connected to an external circuit. Terminals 35 are formed for connecting the basic and configured circuit to an external circuit.

An extended lead wire 13'' is fixed to the external terminal 35 by soldering. The dotted line 36 indicates the point where the unnecessary portion of the Ni plate 11 is cut. This indicates the location. As a more effective manufacturing method of the present invention, for example, as shown in FIG.
In order to prevent an accident in which the lead wiring 13'' extending into the opening 12 of the plate 11 is bent and cannot be connected to the bump of an IC or chip component, a wire of 0.1 mm, for example, is used as shown in FIG. By placing an insulating plate 35 of about 0.3 mm on the lead wiring 13'' and fixing it with an adhesive 36, the above-mentioned accident can be prevented.

Next, an outline of mass production of the embodiment of the present invention shown in FIG. 2 will be explained with reference to FIG. 3.

A Ni plate 51 with a feed hole 50 formed in advance is sent to a step 153 by a guide roller 52, and a punching machine 54 having a desired shape forms an opening 55 for inserting an IC or chip component. Form. In the next step 1156, a Cu foil 57 coated with an adhesive having a thickness of, for example, 35 μm is passed between guide rollers 58 and 59 to be bonded to the Ni plate 51. In step 11160, the photosensitive resin 61 is dropped from the nozzle 62 onto the adjacent guide rollers 63, 63'', and is coated on the Cu foil 57 to a certain thickness, and then in step I.
At 64, the photosensitive resin is dried with an infrared lamp 65. Step V66 is a mask exposure step in which a mask 68 having a pattern 67 for forming Cu lead wiring is adhered onto the Ni plate 5 coated with the photosensitive resin;
Ultraviolet light 70 is irradiated by an ultraviolet lamp 69. The Ni plate 51 having the exposed photosensitive resin film is sent to step VI72 by the guide roller 7. The Ni plate 51 passes through a tank 74 filled with a developer 73 to reveal a Cu lead wiring pattern 75 made of photosensitive resin, and in step NII76, the photosensitive resin pattern 75 swollen by development is removed. Harden with infrared lamp JMoV. Next step 'VlIl7
In step 8, the exposed Cu foil is removed by etching using the photosensitive resin pattern 75 as an etching mask.
The etching liquid is sprayed from a nozzle 79. Step X84 is a process of soldering the Cu lead wire 85 to the solder bump provided on the electrode terminal of the IC or chip component. The IC 86, chip resistor 87, and chip capacitor 88 are placed in dedicated trays 86'', 87'', and 8, respectively.
8'' is conveyed under each opening 55 and heated jig 8
9 descends and performs soldering. For soldered ICs and chip products, a protective resin is further applied to the back side, and after hardening, the step. It is transported to the process of X[90 and cut into the final shape as shown in 92 by a punching machine 91 for die cutting.
In this way, the configuration of the present invention allows a consistent mass production system to be configured. The present invention is a so-called parallel construction method in which the step of creating board wiring and the step of fixing chip components to the board wiring are performed in completely separate steps.

In the example shown in Fig. 1, a substrate and a chip component are mounted, buried in polyimide resin, holes are made on the electrode terminals of the chip component, a metal film is deposited on the entire surface, and a wiring pattern is formed using photolithography. This is the so-called serial construction method, which is completed by forming. For example, if we compare the yield in the case of two processes (assuming the yield in each process is 90%), in the case of the serial method, the final yield is 81% (0.9 x 0.9 = 0.81). In contrast, in the case of parallel construction method,
1-(4). 1 x 0.1) 0.99 and the final yield is 99
%. As described above, the configuration of the present invention can provide an extremely high yield. In the configuration of the conventional example shown in Fig. 1, if a defective chip component such as the 71C is mounted, it is not possible to remove and replace only the defective chip, because the 1C In order to replace the 1C and chip parts, it is necessary to excavate the 1C and chip parts from the polyimide resin.

As a result, the wiring patterns of ICs and chip components are completely damaged. Furthermore, even if the IC or chip parts can be replaced with a new one, the process must start from the initial embedding process with polyimide resin, so in most cases, even if one chip is defective, the entire board must be treated as defective. Therefore, the manufacturing yield was significantly lowered and the manufacturing cost was significantly increased. However, with the manufacturing method of the present invention, by heating the joint between the chip component and the lead again using a heating jig, the chip component can be easily attached and detached and replaced with a good product. In addition, when mounting an IC, etc. on a board by a method other than the example shown in Fig. Furthermore, the above I
Not only is a process necessary for bonding the leads extending from the electrode terminals of the C chip to the wiring board, but also a bonding area is required for bonding the extended leads to the wiring board.

The need for this bonding area directly reduces the packaging density, making it impossible to perform high-density packaging. On the other hand, the present invention requires only the connection between the electrode terminals on the IC chip and the leads, which eliminates the need for the bonding area on the wiring board, which was required in the past. It can be done. Generally, if the lead length is at least 2 mm, the bonding area is required to be 2×(LSI chip peripheral length) i. Furthermore, with the configuration of the present invention, since the metal film can be used as an external lead-out terminal (Fig. 4, 35) of the component circuit, there is no need to add a new external lead-out terminal, resulting in less man-hours and low-cost mounting. It is something that can provide a body. Further, the present invention uses a Ni plate as the base of the mounting body.

A lead wiring pattern is formed directly on this substrate using a metal film. Since the present invention forms the base and lead wiring simply by laminating a metal film on a Ni plate, it does not use expensive polyimide resin as shown in the conventional example, so it is possible to realize an extremely inexpensive mounting body. Since there is no need for a process of forming holes in polyimide resin or the like, it is possible to provide a mounting body at a lower cost.

[Brief explanation of the drawing]

Figures 1a-g are explanatory diagrams of the conventional high-density mounting method;
2A to 2E are cross-sectional explanatory views showing one embodiment of the present invention, FIG. 3 is a cross-sectional view showing an application example of the present invention, FIG. 4 is a plan view of an example of a finished product of the present invention, and FIG. 6 are explanatory diagrams of an application example of the present invention, and FIGS. 7 a to 7 c are perspective views showing an example of a mass production process of the present invention. 40...Metal plate, 41,4"...Opening part, 42...Metal film, 42"...
・Lead wiring, 45... Chip parts, 45''・
...IC.

Claims (1)

[Claims] 1. A step of forming an opening in a metal frame, and a step of forming an insulating adhesive layer on the metal frame,
a step of forming a metal film using the adhesive layer on the metal frame and the opening; and a step of forming the metal film into a wiring pattern, which is continuous with the wiring pattern and protrudes into the opening, by a photoetching method. A step of forming a lead, a step of inserting an element piece into the opening, a step of joining the lead protruding into the opening and the element piece, and a step of cutting the metal frame into a predetermined shape. implementation method.