JPH09172103A - Manufacturing for semiconductor device and glass epoxy substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device and its manufacturing method with no fear of a crack in package in a reflow step, in which a glass epoxy substrate and a printed circuit board are joined electrically, by subjecting the glass epoxy substrate and the solder to heat treatment. SOLUTION: A glass epoxy substrate has a through hole 8 at a storing part for an IC chip 2. A paste of solder 6 is applied onto a mother board 7, and the glass epoxy substrate 1 and the solder 6 are subjected to heat treatment. In a reflow step, when the glass epoxy substrate 1 and the mother board are connected electrically, water accumulated under the IC chip 2 is discharged through the through hole 8. In addition, a film-type adhesive is used for connecting the glass epoxy substrate 1 and the IC chip 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, particularly a semiconductor device based on a glass epoxy substrate, and a method for manufacturing a glass epoxy substrate on which the semiconductor device is mounted.

[0002]

2. Description of the Related Art A semiconductor device having a semiconductor package such as a plastic BGA (Ball Grid Array) and a plastic LCC (Leadless Chip Carrier) based on a conventional glass epoxy substrate will be described by taking the semiconductor device shown in FIG. 4 as an example. .

In the process of assembling a semiconductor device, the glass epoxy substrate 21 and the IC chip 22 are bonded using a paste-like adhesive (mount paste 25), and the electrodes of the glass epoxy substrate 21 and the IC chip 22 are bonded by the bonding wires 23. The electrodes are electrically connected. After that, the IC chip 22 and the bonding wire 23 are sealed by a molding resin 24 for packaging. Then, the packaged semiconductor device is placed on the mother board 27 coated with the paste-like solder 26, heated through a reflow furnace, and soldered to electrically connect the glass epoxy substrate 21 and the mother board 27. Connect to.

[0004]

A problem in the plastic package is a package crack 28. When the glass epoxy substrate 21 is reflowed while absorbing moisture in the atmosphere, the package crack 28 rapidly increases the water vapor pressure of the glass epoxy substrate 21 due to the heat, and the glass epoxy substrate 21 has an internal pressure caused by the water vapor. It can no longer stand and expands and cracks.
The glass epoxy substrate 21 has a higher water absorption rate as compared with the mold resin, and absorbs as much moisture as necessary to cause the package cracks 28 just by leaving it in the air, so that the package cracks 28 easily occur. was there.

Further, the IC is directly mounted on the glass epoxy substrate 21.
Since the chip 22 is adhered, if the adhesion between the two is low, the glass epoxy substrate 21 and the IC chip 22 are reflowed.
There was a problem that the space between them was peeled off due to the water vapor pressure, and thereafter the glass epoxy substrate 21 expanded and cracks 28 were generated.

The present invention has been made in view of the above circumstances, and an object thereof is to prevent a package crack generated in a semiconductor device based on a glass epoxy substrate due to thermal shock during reflow.

[0007]

To achieve the above object, a semiconductor device according to the present invention comprises an IC chip, a glass epoxy substrate having a through hole formed in a housing portion of the IC chip,
This glass epoxy substrate is provided with an adhesive for connecting the IC chip. Further, a step of forming a through hole in the IC chip housing portion of the glass epoxy board, a step of adhering the glass epoxy board having the through hole and the IC chip with an adhesive, and applying paste solder on the mother board. And a reflow step of electrically connecting the glass epoxy substrate and the mother board by heat-treating the glass epoxy substrate and the solder. is there.

Further, there is a method of manufacturing a glass epoxy substrate on which a semiconductor device is mounted, including a step of draining water from the through hole at the time of performing the reflow.
Further, it is preferable to use a film type adhesive as the adhesive, and the material of this adhesive is preferably silicon-modified polyimide.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION A semiconductor device according to an embodiment of the present invention and a method of manufacturing a glass epoxy substrate on which the semiconductor device is mounted will be described below with reference to the drawings. 1 is a sectional view of a semiconductor device according to a first embodiment of the present invention, FIG.
FIG. 3A is a bottom view of the semiconductor device according to the first exemplary embodiment of the present invention.

The semiconductor device in the figure is an SLCC (Stackabl
e Leadless Chip Carrier) type semiconductor package. A through hole 8 is provided at the same time as the processing of the through hole in the housing portion for the IC chip 2 of the glass epoxy substrate 1 serving as the base. The IC chip 2 is bonded onto the glass epoxy substrate 1 using the mount paste 5, and the glass epoxy substrate 1 and the IC chip 2 are electrically connected by the bonding wire 3. After that, the IC chip 2 and the bonding wire 3 are sealed with the potting resin 4 to complete the packaging. Then, the packaged semiconductor device is placed on the mother board 7 to which the paste-like solder 6 is applied, and the glass epoxy board 1 and the solder 6 are heat-treated by passing through a reflow furnace to heat the glass epoxy board 1 and the mother board 6. 7 is electrically connected.

Regarding this SLCC type semiconductor device, 20 semiconductor devices without through holes and 10 semiconductor devices with 5 through holes each having a diameter of 0.3 mm as shown in FIG. 2A were used. After being placed in an oven set to conditions of temperature: 30 ° C., humidity: 60% / RH for 168 hours, reflow at peak temperature: 240 ° C. was repeated 4 times to evaluate reflow resistance.

As a result, substrate cracks were found in the substrate without through holes, but cracks did not occur in the substrate having 5 through holes with a diameter of 0.3 mm in FIG. Also did not occur.

As a modification of the semiconductor device according to the first embodiment of the present invention, a semiconductor device having one through hole having a diameter of 0.3 mm shown in FIG. 2B can be used. . When the reflow resistance was evaluated, substrate cracking was less likely to occur than in the case of a substrate without through holes.

Next, a semiconductor device according to a second embodiment of the present invention and an example of use of the semiconductor device will be described with reference to FIG. FIG. 3 is a sectional view of a semiconductor device according to the second embodiment of the present invention.

The semiconductor device in the figure is a QFN (Quad Flat).
Non-leaded package) type semiconductor package.
IC chip 12 of glass epoxy substrate 11 as a base
The through hole 18 is provided at the same time as the processing of the through hole at the bonding portion of. The IC chip 12 is bonded onto the glass epoxy substrate 11 by using the mount paste 15, and the glass epoxy substrate 11 and the IC chip 12 are bonded by the bonding wire 13.
Are electrically connected. After that, the IC chip 12 and the bonding wire 13 are sealed with the mold resin 14, and the packaging is completed. After that, paste 1 solder
The packaged semiconductor device is placed on the mother board 17 coated with 6 and passed through a reflow furnace to heat the glass epoxy board 11 and the solder 16 to electrically connect the glass epoxy board 11 and the mother board 17. To do.

Similar to the case of the first embodiment, there are three kinds of (A) no through hole, (B) one through hole having a diameter of 0.3 mm, and (C) five through holes having a diameter of 0.3 mm. When the semiconductor device was pretreated under the conditions of temperature: 30 ° C. and humidity: 60% / RH and reflow resistance was evaluated twice by repeating reflowing, the occurrence of cracks due to the difference in pretreatment time was confirmed. It is as shown in Table 1 below.

[0017]

[Table 1]

From these results, when the number of through-holes is one, the pre-treatment time: 120 hours before the substrate crack does not occur, and when the number of through-holes is five, the pre-treatment is 2 times.
It can be seen that the substrate does not crack even after 88 hours.

The number and size of the through-holes are not limited to those in the first and second embodiments, and the larger effect can be obtained by increasing the number or the diameter as long as the strength of the substrate can be maintained. It is also possible.

Also, using the first and second embodiments, as the adhesive between the glass epoxy substrates 1 and 11 and the IC chips 2 and 12, instead of the mount pastes 5 and 15, a film type silicon modified polyimide adhesive is used. The agent may be used, for example, with a thickness of 30 μm. For example, the adhesion strength between the glass epoxy substrate 1 used in the SLCC type semiconductor package of FIG. 1 and the silicon modified polyimide film type adhesive is as shown in Table 2 below.

[0021]

[Table 2]

The value of this adhesion strength is within the range where wire bonding is possible. Furthermore, the glass epoxy substrate 1 of the above sample has a heat resistant temperature of 286 ° C., and since the mounting process is performed at this temperature or lower, this adhesion strength can sufficiently withstand the semiconductor process. By using this film type adhesive, it is possible to prevent the adhesive from leaking from the through hole during the reflow and the amount of the adhesive varying depending on the location.

If a film-type adhesive agent is used for bonding with the same size as the IC chip 2 or one size larger than the IC chip 2, the glass epoxy substrate 1 and the IC are bonded together.
Since there is no gap between the chips 2, the adhesion between the glass epoxy substrate 1 and the IC chip 2 is improved as compared with the mount paste 5. When reflowing, water easily accumulates in places with low adhesion and cracks easily occur, but by using a film-type adhesive, it is possible to prevent moisture from collecting in certain places, which is effective against package cracks due to water vapor pressure. Act on.

[0024]

According to the present invention, by forming a through hole in the IC chip housing portion of the glass epoxy substrate, it is possible to prevent package cracks caused by the accumulation of water under the IC chip during reflow.

[Brief description of the drawings]

FIG. 1 is a sectional view of a semiconductor device according to a first embodiment of the present invention.

FIG. 2A is a bottom view of the semiconductor device according to the first embodiment of the present invention. (B) It is a bottom view of the modification of the semiconductor device of the 1st example of the present invention.

FIG. 3 is a sectional view of a semiconductor device according to a second embodiment of the present invention.

FIG. 4 is a sectional view of a conventional semiconductor device.

[Explanation of symbols]

1, 11, 21 ... Glass epoxy substrate, 2, 12, 22
... IC chip, 3, 13, 23 ... Bonding wire, 4 ... Potting resin, 5, 15.25 ... Mount paste, 6, 16, 26 ... Solder, 7, 17, 27 ...
Mother board, 8, 18 ... Through hole, 9, 19, 29 ... Pattern, 14, 24 ... Mold resin, 28 ... Substrate crack

Claims (6)

[Claims] 1. A semiconductor device comprising an IC chip, a glass epoxy substrate having a through hole formed in a housing portion of the IC chip, and an adhesive for connecting the glass epoxy substrate and the IC chip. . 2. The semiconductor device according to claim 1, wherein the adhesive is a film type adhesive. 3. A step of forming a through hole in an IC chip housing portion of a glass epoxy substrate, a step of adhering the glass epoxy substrate having the through hole and the IC chip with an adhesive, and a paste-like solder on a mother board. And a reflow step of electrically connecting the glass epoxy substrate and the mother board by heat-treating the glass epoxy substrate and the solder. Production method. 4. The method for manufacturing a glass epoxy substrate having a semiconductor device according to claim 3, further comprising a step of draining water from the through hole during the reflow step. 5. The method for manufacturing a glass epoxy substrate on which a semiconductor device is mounted according to claim 3, wherein the adhesive is a film type adhesive. 6. The material of the film type adhesive is
The semiconductor device according to claim 5, which is a silicon-modified polyimide.