JP2643856B2 - Wire bonding method for hybrid IC - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hybrid IC wire bonding method, and more particularly to a hybrid IC mounted on both sides of a substrate.
A wire bonding method.

[0002]

2. Description of the Related Art Hybrid ICs have been used in which high-density mounting is realized by mounting IC pellets on both sides of a substrate.

FIG. 3 is a schematic sectional view for explaining a conventional hybrid IC wire bonding method.

As shown in FIG. 3, a first IC pellet 7 is mounted on one surface of a wiring board 6, and an electrode pad of the IC pellet 7 is connected to a wiring layer of the wiring board 6 by a bonding wire 8. Then, after sealing the portion including the IC pellet 7 and the bonding wire 8 with the precoat resin 10,
The surface where the IC pellet 7 is mounted is placed on the concave portion 2 of the wire bonding apparatus in which the concave portion 2 is formed on the upper surface of the heated heater block 1, and the peripheral portion of the wiring substrate 6 is fixed with the clamper 14. The second IC pellet 12 is die-bonded to the other surface of the
Between the electrode pad of the C pellet 7 and the wiring layer of the wiring board 6
The had been wire bonding.

[0005]

In this conventional hybrid IC wire bonding method, a protruding portion of a first IC pellet mounted on one surface of a wiring substrate and pre-coated is provided on a second surface of the wiring substrate. There is a space between the wiring board and the heater block when wire bonding is performed toward the concave portion formed in the heater block when mounting the IC pellet, so that extra space is required until the wiring board is heated to a desired temperature. There is a problem that time is required, and the wiring board is deformed or vibrated by a bonding load at the time of wire bonding, thereby causing a bonding failure.

It is an object of the present invention to provide a wire bonding method for improving the reliability of a double-sided hybrid IC.

[0007]

SUMMARY OF THE INVENTION A wire bonding method for a hybrid IC according to the present invention includes a step of pre-coating a first IC pellet mounted on one surface of a wiring board and wire-bonded with a resin, and an upper surface of a heater block. a diaphragm for sealing the upper end of the formed recesses in sealed before
After mounting the wiring board on which the first IC pellet is mounted on the diaphragm of the wire bonding apparatus in which the inside of the concave portion is filled with the heating liquid so that the resin surface faces down, the heating liquid in the concave portion is formed. Adjust the pressure of the resin surface
The diaphragm is brought into close contact with the
And a step of mounting a second IC pellet on the other surface of the wiring substrate having a resin surface in contact with the diaphragm and performing wire bonding. .

[0008]

Next, the present invention will be described with reference to the drawings.

FIGS. 1A to 1C are schematic sectional views showing a first embodiment of the present invention in the order of steps for explaining the first embodiment.

First, as shown in FIG. 1 (a), a concave portion 2 is provided on the upper surface, and is attached to the upper end of a heater block 1 provided with an inlet 3 on the bottom surface of the concave portion 2 to seal the upper end of the concave portion 2. Fluororesin with a thickness of about 0.1 to 0.5 mm or a thickness of 0.2
A ceramic board or a glass epoxy board (epoxy board containing glass fiber) having a size of 60 mm × 80 mm and a thickness of 1 mm is provided on the upper surface of the heater block 1 of the wire bonding apparatus provided with the diaphragm 4 made of silicone rubber of about 1.0 mm. )), A wiring board 6 having a wiring layer formed thereon is placed thereon, and the wiring board 6 is pressed down by a first window clamper 9 having a window provided in a portion corresponding to the position of an IC pellet mounted on the wiring board 6. And fix it, about 150
A heating liquid 5 such as silicone oil, which is filled and injected into a closed recess 2 through an injection port 3 of a heater block 1 heated to a temperature of 150 ° C. and heated to about 150 ° C. by a heater block 1 ^The IC pellet 7 is die- bonded to the upper surface (one surface) of the wiring substrate 6 in a state where the surface of the diaphragm 4 is pressed against the lower surface of the wiring substrate 6 by applying a pressure of ² Pa.
And the electrode pads of the IC pellet 7 and the wiring substrate 6
(Wire bonding) between the wiring layers.

At this time, a bonding load of 0.5
Although a force of about 2.0 N is repeatedly applied to the IC pellet 7 and the wiring board 6, the wiring board 6 is supported by the heating liquid 5 with a force of about 10 N and does not bend.

Next, as shown in FIG. 1B, a portion including the IC pellets 7 and the bonding wires 8 of the wiring board 6 removed from the wire bonding apparatus is sealed with a precoat resin 10 such as an epoxy resin.

Next, as shown in FIG. 1C, the surface (one surface) of the wiring board 6 on which the IC pellets 7 are mounted is brought into contact with the diaphragm 4 of the wire bonding apparatus (upside down). After being placed downward and fixed with the second window clamper 11, the I
Similarly to the case where the C pellet is mounted, the IC pellet 12 is mounted on the other surface of the wiring board 6 and the bonding wire 1 is mounted.
At 3, wire bonding is performed between the electrode pads of the IC pellet 12 and the wiring layer of the wiring board 6.

At this time, a pre-coated IC pellet 7 protrudes from one surface of the wiring substrate 6 facing the diaphragm 4, but the diaphragm 4 has flexibility so that the IC pellet 7 adheres to the uneven surface and deforms. In addition, the temperature and pressure required for wire bonding can be applied to the wiring board 6.

Thereafter, the portion including the IC pellets 12 and the bonding wires 13 is sealed with a precoat resin, the wiring substrate 6 is divided, and external leads are attached to each of the divided substrates. Seal.

FIG. 2 is a schematic sectional view for explaining a second embodiment of the present invention.

As shown in FIG. 2, the peripheral portion of the wiring board 6 placed on the upper surface of the heater block 1 of the wire bonding apparatus is pressed and fixed by the clamper 14 and brought close to above the center of the wiring board 6. It has the same configuration as that of the first embodiment except that a displacement sensor 15 is provided. By detecting the amount of displacement in which the central portion of the wiring board 6 is pushed up by the pressure of the heating liquid 5 and deformed, In addition, since the pressure of the heating liquid 5 can be controlled, even when the size and the position (layout) of the IC pellet mounted on the wiring board 6 are different, a window clamper having a different pattern is not required, and the versatility is improved. There is the advantage of increasing.

Further, even if the heating liquid is supplied erroneously when the wiring board is not mounted, an abnormality is detected by the displacement sensor and the supply is automatically stopped, so that the diaphragm is not damaged. There is also.

[0019]

As described above, according to the present invention, the IC pellets are formed on both sides of the wiring board by providing a diaphragm for sealing the upper end of the recess provided on the upper surface of the heater block and supplying the heating liquid into the recess. In the case of wire bonding when mounting, the flexible diaphragm can be used to apply the temperature and pressure necessary for wire bonding to the wiring board by closely contacting the uneven surface, preventing wire bonding defects and improving the reliability of the hybrid IC. It has the effect of being able to improve.

Further, since heat can be quickly conducted from the heating liquid to the wiring board via the diaphragm, the bonding time can be shortened and the working efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view shown in the order of steps for explaining a first embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view for explaining a second embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view for explaining a conventional hybrid IC wire bonding method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heater block 2 Depression 3 Injection port 4 Diaphragm 5 Heating liquid 6 Wiring board 7,12 IC pellet 8,13 Bonding wire 9,11 Window clamper 10 Precoat resin 14 Clamper 15 Displacement sensor

Claims (4)

(57) [Claims] 1. A first IC pellets wire bonding mounted on one surface of the wiring substrate and the step of pre-coating a resin, is sealed has a diaphragm for sealing the upper end of the recess formed on the upper surface of the heater block Inside the recess
After the resin surface of the wiring substrate on which the first IC pellet is mounted on the diaphragm of the filled wire bonding apparatus in the heating liquid is mounted so as to lower the front
The pressure of the heating liquid in the recess is adjusted so that the resin surface
Adhere the diaphragm and wire bond to the wiring board
Applying a temperature and a pressure necessary for the wiring, and a second surface of the wiring substrate having the resin surface abutted on the diaphragm.
Mounting the IC pellet and performing wire bonding. 2. The method according to claim 1, wherein the wiring substrate is a ceramic substrate or a glass epoxy substrate. 3. The method according to claim 1, wherein the diaphragm is made of a fluorine resin or a silicone resin. 4. The method according to claim 1, wherein the heating liquid comprises silicone oil.