JPH06104295A - Soldering of hybrid ic - Google Patents

Abstract

PURPOSE:To increase the workability and to reduce the size by mounting a plurality of bare chips simultaneously on a body to which the chips, etc., are to be bonded. CONSTITUTION:A substrate 2 is located on a carbon-made first jig 1. A carbon- made second jig 5 having a plurality of through holes 5a is mounted on the substrate 2. Then, bare chips and solder foils 3 are located on parts of the substrate 2 which are within the through holes 5a. Pressing sections 7a of a carbon-made third jig 7 having the pressing sections 7a of the same number as that of the through holes 5a are put into the through holes 5a and are located above the bare chips 4. This is heated in hydrogen reducing gas, with vertical load applied to the third jig 7, and the bare chips 4 are bonded onto the substrate 2 simultaneously or the substrate 2 is bonded to a package 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for soldering a hybrid IC in which bare chips such as power FETs, diodes and transistors are mounted on a substrate.

[0002]

2. Description of the Related Art Conventionally, in manufacturing a hybrid IC of this type, in order to mount a bare chip such as a power FET on a substrate, as shown in FIG. 5, the bare chip 10 is first formed into a preform-shaped solder foil 11. Is placed on a bonded article 13 such as a substrate provided on the heating device 12 by using, and then, as shown in FIG. 6, while pressing from the upper surface of the bare chip 10 via a pressing jig 14, as indicated by an arrow. While scribing to the left and right, it was heated by a heating device 12 such as a heat plate to melt the solder foil 11 and bond it to the bonded article 13 to form an ohmic contact.

However, in the case of a hybrid IC having a plurality of bare chips 10 mounted therein, a pressing jig 14 or
There is a problem that downsizing is difficult because a work space considering the scribe area is required.

[0004]

Therefore, as an improvement thereof, as shown in FIG. 7, one to three bare chips 10 are mounted on a bonded article such as a substrate 13 or a heat dissipation plate 15, and ohmic contacts are preliminarily provided. After that, there is a method of mounting the assembly in the case 16, but in this case, there is a problem that the work is complicated.

The present invention has been proposed in view of the above circumstances, and an object thereof is to solder a plurality of bare chips on a bonded object at the same time, to improve workability and to reduce the size of the hybrid IC solder. It is to provide the attachment method.

[0006]

According to the present invention, a substrate 2 is placed on a first jig 1 made of carbon, and a second jig 5 made of carbon having a plurality of through holes 5a is placed thereon. A bare chip 4 and a solder foil 3 are located in the through holes 5a and on the substrate 2 and made of carbon having a corresponding number of pressing portions 7a in the through holes 5a.
The pressing portion 7a of the jig 7 is placed on each bare chip 4 and is heated in a hydrogen reducing gas while applying a vertical load to the third jig 7 to simultaneously heat the bare chips 4 at the same time. The above-mentioned object is achieved by being bonded to the substrate 2. In addition, the substrate 2 is placed on the package 6 via the solder foil 3a, and the second jig 5 made of carbon having a plurality of through holes 5a is placed.
Is located on the substrate 2 within the through hole 5a,
The pressing portions 7a of a third jig 7 made of carbon having a corresponding number of pressing portions 7a are placed in the through holes 5a and are positioned on each bare chip 4 in a direction perpendicular to the third jig 7. The above object is achieved as a configuration in which each bare chip 4 is simultaneously bonded to the substrate 2 and the substrate 2 is bonded to the package 6 while being heated in a hydrogen reducing gas while applying the load.

[0007]

As described above, according to the present invention, a plurality of bare chips 4 are used.
Is pressed all at once in the vertical direction by a carbon jig 7 to bond it to the substrate 2, and the pressure jig is not scribed as in the conventional case, so no space is taken and the device, the substrate 2, etc. are downsized. It can be done and the workability is also good. Further, soldering is performed by using jigs 1, 5, 7 made of carbon, etc. The solder of carbon is hard to be wet (hard to adhere), and the coefficient of thermal expansion is close to that of other materials. In addition, a large number of bare chips 4 can be mounted on the substrate 2 all at once, and wiring can be performed by a circuit on the substrate 2, and the number of wiring wires can be reduced in the case where a wire bonding process is required. Furthermore, bare chip bonding to the substrate 2 and substrate bonding to the package 6 can be performed at the same time. In this case,
The soldering process can be reduced, and the assembly workability is improved.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an exploded perspective view of an apparatus used in a soldering method according to the present invention, and FIG. 2 is a sectional view showing a state in which the apparatus is set. In the drawings, reference numeral 1 is a first jig made of carbon. This jig 1 has a substrate mounting surface 1a having a substantially corresponding shape of a substrate 2 formed on a bottom plate 1b, and an outer peripheral portion of the bottom plate 1b. A rib-shaped support portion 1c is formed to prevent the position of the substrate 2 from being displaced.

The substrate 2 has a horizontally long rectangular shape in the illustrated example, and a plurality of blocks of conductors 2a having a predetermined circuit pattern are formed on the upper surface thereof, and a high melting point preform-shaped solder foil 3 is formed on each conductor 2a. The bare chip 4 is mounted via the.

Reference numeral 5 denotes a second jig made of carbon for pressing the peripheral portion of the substrate 2. This second jig 5
Through holes 5a corresponding to the number of bare chips 4 mounted on the substrate 2 are formed from the upper surface to the lower surface at intervals in the length direction of the jig 5. As shown in FIG. 3, grooves 5b and 5c are formed on the side portions so that the jigs 5 can be fitted into the box-shaped package 6 in which the jig 5 is housed while being positioned. ing.

Referring again to FIG. 1, 7 is a carbon-made third
The jig is formed into a comb shape, is inserted into the through hole 5a, is in contact with the bare chip 4, and has a plurality of pressing portions 7a in the shape of, for example, a rectangular rod that press the bare chip 4. In addition, 8 is a loader such as a copper plate set on the third jig 7 and having a predetermined weight for pressing the assembly of the jig 7 and the like.

Next, a method of soldering the bare chip 4 on the substrate 2 will be described. First, the substrate 2 is placed on the first jig 1, and the solder foil 3, the bare chip 4 and the like are attached to the conductor 2a.
put on top. Then, the second jig 5 is set and the solder foil 3 and the bare chip 4 are positioned. The placement and positioning of the solder foil 3 and the bare chip 4 may be performed through the through hole 5a after the second jig 5 is set. That is, the through hole 5a has a positioning function for the bare chip 4. Then, the third jig 7 is set, the pressing portion 7a is placed on the bare chip 4, the load body 8 is placed on the jig 7, and pressure is applied by the load. In this pressurized state,
These assemblies are placed in a hydrogen reducing gas, and are heated by a heating device (not shown) having an appropriate configuration to melt the high melting point solder foil 3, whereby solder joining can be performed.

When the above solder joining is completed, the assembly is disassembled and the substrate 2 to which the bare chip 4 is joined is taken out,
If necessary, wire bonding is used to connect the necessary parts.

Next, the substrate 2 is placed in the package 6 shown in FIG.
Solder joint. As the solder in this case, a preform-shaped solder foil having a melting point lower than that of the solder foil 3 having the bare chip connection is used. This is because if the melting points are the same, the already existing bare chip bonding will be hindered. In this board bonding, the solder foil is placed in the package 6 and the board 2 is placed thereon. Then, the second jig 5 is placed in the package 6 with the grooves 5b and 5c and the projecting portion 6a on the package 6 side aligned, and a load is applied by the load body 8 shown in FIG. Substrate bonding can be performed by heating in a hydrogen reducing gas in this state. In this case, although not particularly shown, the lower surface of the jig 5 is of course shaped so as not to cut the wire by the above wire bonding.

In the case where the wiring between the bare chip 4 and the substrate 2 can be performed by the circuit pattern of the conductor 2a, the bare chip bonding and the substrate bonding can be performed at the same time, and the soldering process can be reduced.

FIG. 4 shows an example of an apparatus used in that case. That is, the solder foil 3a is placed in the package 6,
If the substrate 2 and the solder foil 3 are placed thereon and the second jig 5, the third jig 7 and the load body 8 are set and heated in a hydrogen reducing gas, bare chip bonding and substrate bonding are performed at the same time. be able to. In this case, the first jig 1 shown in FIG. 1 can be omitted. The solder foils 3 and 3a may have the same or substantially the same melting point.

[0017]

As described above, according to the present invention, the bare chips 4 placed on the substrate 2 are pressed against the plurality of bare chips 4 by pressing the pressing portions 7a of the jigs 7 made of carbon respectively in the vertical direction. The solder foil 3 should be joined at once,
Since it does not involve a step of scribing a pressure jig as in the conventional case, a plurality of bare chips 4 can be simultaneously bonded to a narrow place without taking up a space, and the workability is good and the size can be reduced. it can. Further, since the jigs 1, 5, and 7 made of carbon are used, this material is hard to be wet with solder, and its thermal expansion is close to that of other materials (bare chip 4, substrate 2). There is no stress added to such.

Further, the substrate 2 is placed on the package 6 with the solder foil 3a interposed therebetween, and a plurality of through holes 5 are provided.
The second jig 5 made of carbon having a is placed, the solder foil 3 and the bare chip 4 are positioned in the through holes 5a and on the substrate 2, and a corresponding number of pressings are performed in the through holes 5a. Third jig 7 made of carbon and having a portion 7a
Put the pressing portion 7a of the above to position on each bare chip 4,
The third jig 7 is heated in a hydrogen reducing gas while applying a vertical load to bond the bare chips 4 to the substrate 2 at the same time, and bond the substrate 2 to the package 6. By doing so, bare chip bonding and substrate bonding can be performed at the same time, and the soldering process is reduced.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of an example of a device used in the present invention.

FIG. 2 is a cross-sectional view of the above assembled state.

FIG. 3 is an exploded perspective view of an apparatus when bonding a substrate to a package.

FIG. 4 is a cross-sectional view of an assembled state of a device that simultaneously performs bare chip bonding and substrate bonding.

FIG. 5 shows a conventional example.

FIG. 6 is an operation explanatory view of a conventional example.

FIG. 7 shows another conventional example.

[Explanation of symbols]

 1 1st jig 1a Substrate storage part 1b Bottom plate 1c Support part 2 Substrate 2a Conductor 3,3a Solder foil 4 Bare chip 5 Second jig 5a Through hole 5b, 5c Groove 6 Package 6a Projection 7 Third jig 8 load body

Claims (2)

[Claims] 1. A substrate (2) is placed on a first jig (1) made of carbon, and a second jig (5) made of carbon having a plurality of through holes (5a) is placed thereon. , The bare chip (4) and the solder foil (3) are located in the through hole (5a) and on the substrate (2), and the corresponding number of pressing portions (7a) are provided in these through holes (5a). The pressing portion (7a) of a third jig (7) made of carbon having carbon is placed on each bare chip (4) and hydrogen is applied to the third jig (7) while applying a vertical load. Hybrid IC characterized by heating in a reducing gas to simultaneously bond the bare chips (4) to the substrate (2)
Soldering method. 2. A solder foil (3a) on the package (6).
The substrate (2) is placed over the second jig (5) made of carbon having a plurality of through holes (5a), and the solder foil (3) and the bare chip (4) are placed in the through holes (5a). Of the third jig (7), which is made of carbon and is located on the substrate (2) and has a corresponding number of pressing portions (7a) in the through holes (5a). 7a) is placed on each bare chip (4) and heated in a hydrogen reducing gas while applying a vertical load to the third jig (7), and each bare chip (4) is simultaneously placed on the substrate. A method for soldering a hybrid IC, characterized in that it is joined to (2) and the substrate (2) is joined to the package (6).