JPH0955597A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the adhesion of a shield layer to the surface of sealing resin in a package where an IC chip or other passive element chip is mounted in a recess of a wiring board and the recess is sealed and then the sealed part is further sealed by printing a conductor paste. SOLUTION: An IC chip 14 or other passive element chip is mounted on an inner conductor layer 19 in a recess 13 of a wiring board 10 and the recess is sealed. A conductive adhesive, e.g. Ag paste, is then printed onto a region simultaneously covering the sealed part 16 and a neighboring GND pattern part 20 for contact thus forming an adhesion enhancement layer 18. Furthermore, a conductor paste of Cu, for example, is printed to form a shield layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly to a shield structure for a thin and leadless type surface mount hybrid integrated circuit device.

[0002]

2. Description of the Related Art FIG. 2 shows a conventional shield structure of a leadless type surface mounting IC package. In FIG. 2, the IC chip (14) is mounted on the bottom surface of the recess (13) of the wiring board (10) and sealed with the sealing resin (16). Then, a stable potential of the surface of the sealing resin (16) and the surface of the wiring substrate (10) that is flush with the surface of the sealing resin (16), typically a ground potential (hereinafter referred to as GND), is applied. Straddling a part of the conductor pattern,
A shield layer (17) was formed by printing a high-conductivity conductor paste such as Cu.

In this case, the main component of the sealing resin (16) is an epoxy type, but in many cases, a silicon type component is included as a measure against the warpage of the substrate. In most cases, a resist is printed on the shield layer (17) to prevent the oxidation of the shield layer (17) to form a protective layer (21).

[0004]

In the conventional shield structure shown in FIG. 2 described above, when the sealing resin contains a silicon-based component, the adhesion of the high-conductivity conductor paste to the shield layer is not sufficient. However, for example, according to the result of the cross-cut test (JIS standard: K5400), stable results cannot be obtained. Particularly, the thicker the film thickness of the shield layer and the upper protective layer is, the worse the test result is, and the remaining pattern after peeling. The number was around 50%, and sometimes it was 0%.

However, in order to improve the above-mentioned adhesion,
After removing the silicon-based component from the encapsulation resin, this time,
The warp of the substrate becomes remarkable, and it becomes 0.
A warp of 2 mm or more may occur, which causes a problem of a fatal defect for a surface mount package.

[0006]

A feature of the present invention is that a recess is formed in a part of one main surface of a wiring board having an internal conductor layer, excluding the substrate end, to expose a part of the internal conductor layer. Then, one or more IC chips or passive element chips were mounted in the recess, and the mounted chip and a part of the internal conductor layer were connected by a bonding wire, solder, bump, or conductive adhesive. After that, the recess is sealed with a non-conductive sealing resin so that the surface of the sealing resin and the main surface of the wiring board are substantially flush with each other. In a semiconductor device that continuously prints a conductive shield pattern covering a part or all of a conductor pattern pad on the surface from one surface of the sealing resin to one main surface of the wiring board. Before printing the shield layer, the shield layer The sealing region to be covered are those that are preprinted with conductive adhesive.

Further, the present invention is the above semiconductor device, wherein the shield layer is a layer formed of Cu paste and the adhesion enhancing layer is a layer formed of Ag paste. Specifically, after mounting an IC chip or another passive element chip in the recess of the wiring board and sealing the recess, Ag paste or the like is applied to a region that simultaneously covers the sealing part and the contact GND pattern part in the vicinity thereof. The conductive adhesive is printed, and a conductor paste such as Cu is printed on the conductive adhesive printing area to form the shield layer.

[0008]

According to the present invention, in a package in which an IC chip or another passive element chip component is mounted in a recess of a wiring board, the recess is sealed, and the sealed area is shielded by conductor paste printing, By forming a new adhesion enhancement layer between the shield layer and the sealing resin in the conventional example, the adhesion of the shield layer to the sealing resin is improved and improved.

[0009]

Embodiments of the present invention will now be described with reference to the drawings.

[0010]

1 is a cross-sectional view of a shield structure of an embodiment of the present invention applied to a leadless type IC package. As shown in FIG. 1, in manufacturing these shield structures, first, the concave portion (1) of the wiring board (10) is formed.
3) The IC chip (14) or another passive element chip (not shown) is mounted on the mounting land pattern of the internal conductor (19) exposed inside by a conductive adhesive, and the IC chip (14) and the internal conductor are mounted. After wire bonding with the wire (15) to the other parts of the layer (19) to make an electrical connection, the resin surface of the sealing resin (16) becomes the substrate surface (the main surface of the circuit board). The resin is filled so as to match within a range of about ± 0.05 mm so that the resin surface after the sealing resin is dried and the substrate surface form a part of substantially the same plane. Note that (12) is a GND pattern, and the through holes for contacts are omitted.

Thereafter, a conductive adhesive such as Ag paste is printed in a region covering at least a part or all of the sealing resin (16) and the GND pattern for contact (20) with a thickness of 10 to 50 μm, for example. It is cured by drying at 150 ° C. for about 30 minutes to form an adhesion strengthening layer (18). Thereafter, a conductor paste such as Cu paste is printed at a thickness of, for example, 10 to 50 μm so as to cover a part or the whole of the area of the adhesion reinforcing layer (18), and 15
It is cured by drying at 0 ° C. for about 30 minutes to form a shield layer (17).

As described above, in the present invention, the adhesion layer (18) is newly formed between the shield layer (17) and the sealing resin (16) in the conventional example, so that the shield layer (17) is formed. It is intended to improve the adhesion of (1) to the sealing resin (16). In order to prevent the shield layer (17) from being oxidized, a solder resist or the like is printed on an area covering the entire shield layer as needed, and the shield layer (17) is dried at 150 ° C. for about 15 minutes to be hardened, whereby the protective layer (21) is formed. To form.

[0013]

As described above, the shield structure of the present invention is extremely light and thin, while maintaining the features of the present semiconductor device in which the shield pattern covering the mounting area of the component mounting surface is provided. This has the effect of greatly improving the adhesion of the shield layer to the sealing surface. For example,
According to the test result by the cross-cut test (JIS standard: K5400), it is very difficult to obtain a good result in the past, and both the shield layer and the protective layer have a thickness of about 20 μ, which is stable unless sufficient uniformity is secured. However, according to the shield structure of the present invention,
Even if there is variation in the film thickness of about 50 μ, 100% stable adhesion can be obtained. Therefore, the reliability of the IC package is remarkably improved, and it is possible to provide an IC package having an extremely stable shield effect.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a semiconductor device of a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a conventional semiconductor device.

[Explanation of symbols]

 10 Wiring Board 11 End Face Electrode 12 Back Shield Pattern 13 Recess 14 IC Chip 15 Bonding Wire 16 Sealing Resin 17 Shield Layer 18 Adhesion Strengthening Layer 19 Internal Conductor Layer 20 GND Pattern for Contact 21 Protective Layer

Claims (2)

[Claims] 1. A concave portion is formed in a part of one main surface of a wiring board having an internal conductor layer excluding a substrate end portion to expose a part of the internal conductor layer, and an IC chip or a passive element is formed in the concave portion. Bonding wire, solder,
After connecting the mounted chip and a part of the internal conductor layer with a bump or a conductive adhesive, the recess is sealed with a non-conductive sealing resin, and the surface of the sealing resin is A main surface of the wiring board is formed to be substantially flush with the main surface of the wiring board, and a conductive shield pattern for covering a part or all of the conductor pattern pad is formed of the sealing resin. In a semiconductor device in which a shield layer is formed by continuously printing from the surface to one main surface of the wiring board, a conductive adhesive is printed between the shield layer and the sealing resin. A semiconductor device having an adhesion enhancement layer. 2. The semiconductor device according to claim 1, wherein the shield layer is a layer formed of Cu paste, and the adhesion enhancing layer is a layer formed of Ag paste.