JP2000357759A - Semiconductor device - Google Patents

Abstract

[PROBLEMS] To provide a semiconductor device capable of reliably performing light shielding on a semiconductor IC chip while maintaining the adhesive strength between the semiconductor IC chip and a wiring board. SOLUTION: A semiconductor IC chip 2 is mounted on a wiring board 1 provided with signal metal patterns 3 on both sides thereof through a resin 5 by a face-down mounting method. The signal wiring pattern 3 includes a mounting-side signal wiring pattern 3a disposed on the semiconductor IC chip mounting surface 1a of the wiring board 1.
And a back signal wiring pattern 3b disposed on a back surface 1b opposite to the semiconductor IC chip mounting surface 1a. In the region where the semiconductor IC chip 2 is mounted on the semiconductor IC chip mounting surface 1a, a gap 8 where the back side signal wiring pattern 3b is not arranged is provided.
The light shielding pattern 6 is provided in accordance with the shape of.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor device, and more particularly to a semiconductor device in which a semiconductor IC chip is mounted on a wiring board by a face-down mounting method.

[0002]

2. Description of the Related Art Conventionally, LSI (Large Scale Integr
ation) A semiconductor IC chip having a bump formed on an LSI circuit surface on which a circuit is formed is connected to a wiring board on which a wiring pattern is formed via the bump, and the semiconductor IC chip is connected between the semiconductor IC chip and the wiring board. Fill the portion where the bumps are not arranged with a conductive adhesive such as epoxy resin,
A face-down mounting type semiconductor device which maintains mechanical strength by the conductive adhesive is well known.

A conventional semiconductor device as described above is disclosed in JP-A-7-106373 and JP-A-61-18606.
No. 1 discloses this. FIG.
373 shows the configuration of a semiconductor device disclosed in Japanese Patent Application Laid-Open No. 186606/1986, and FIG. 6 shows the configuration of a semiconductor device disclosed in Japanese Patent Application Laid-Open No. 61-186061.

The semiconductor device shown in FIG. 5 is connected to a semiconductor IC chip 12 via bumps 14 provided on the semiconductor IC chip 12.
The chip 12 and the wiring pattern 13 on the substrate 11 are connected, and the resin 1 is inserted into a gap between the semiconductor IC chip 12 and the substrate 11.
5 is filled. In the semiconductor device shown in FIG. 6, the semiconductor IC chip 22 and the substrate 2 are bonded by bonding pads 24 provided on the semiconductor IC chip 22.
1, and an anisotropic conductive film 25 is disposed between the semiconductor IC chip 22 and the substrate 21. By applying a temperature and a pressure between the semiconductor IC chip 22 and the substrate 21 with the anisotropic conductive film 25 interposed therebetween, batch mounting becomes possible. 2
6 is a protective film.

In the above-described face-down mounting type semiconductor device, the LSI circuit surface of the semiconductor IC chip faces the wiring board. However, since glass fiber-containing epoxy resin widely used as a wiring substrate easily transmits light, light transmitted through the wiring substrate impinges on the LSI circuit surface of the semiconductor IC chip.

When light is applied to the semiconductor, electrons in the charge band and impurity level absorb the energy of the light, causing photoconductivity inside the semiconductor and photoelectromotive force at the interface.
A malfunction of the SI circuit is caused. This phenomenon is caused especially by infrared rays. EPROM (Erasable Progr.
In the case of an LSI circuit such as an ammable read-only memory, care must be taken because internal data is erased when irradiated with ultraviolet rays.

As means for solving the above problems,
2. Description of the Related Art Conventionally, a configuration has been considered in which a metal pattern is provided on a wiring board to block light such as infrared light (hereinafter referred to as light shielding). The following two are conceivable as semiconductor devices using such a light shielding method. In the semiconductor device described below, a wiring pattern is provided also on the back surface of a wiring board like an IC (Integrated Circuit) card, and the wiring pattern on the back surface has a wide area to which different signals are supplied. And a plurality of metal patterns having

As shown in FIG. 7, a wiring board 31 having signal metal patterns (wiring patterns) 33 provided on both surfaces thereof
, The semiconductor IC chip 32 is mounted on the surface on which the semiconductor IC chip 32 is mounted (semiconductor IC chip mounting surface).
2. A semiconductor device in which a light-shielding film made of a metal material is provided so as to have the same shape as in No. 2, and a resin 35 is provided between the wiring board 31 and the semiconductor IC chip 32.

As shown in FIG. 8A, in a wiring board 41 provided with signal metal patterns (wiring patterns) 43 on both surfaces, a light shielding pattern 44 is provided on a surface (back surface) on which the semiconductor IC chip 42 is not mounted. A semiconductor device provided with. Incidentally, reference numeral 42 denotes a semiconductor IC chip, and reference numeral 45 denotes a resin.

[0010]

However, the above-mentioned conventional semiconductor devices have the following problems.

As in the semiconductor device of FIG. 1, the same size as the LSI circuit is provided on the semiconductor IC chip mounting surface of the wiring board 31.
That is, when the light-shielding film 34 having substantially the same size as the semiconductor IC chip 32 is provided, the resin 35 filled between the semiconductor IC chip 32 and the wiring board 31 and the wiring board 31
And the area of adhesion with the substrate becomes extremely small. Typically,
There is a difference between the adhesive strength between glass-filled epoxy resin and resin used as a wiring board and the adhesive strength between metal and resin. The adhesive strength between metal and resin is the bond strength between glass-fiber-filled epoxy resin and resin. Less than strength. Therefore, in such a configuration, the semiconductor IC chip 32 and the wiring board 31
And the adhesive strength with the adhesive greatly decreases.

On the other hand, when a light-shielding pattern 44 is provided on the back side of a wiring board 41 as in the case of a semiconductor device, the resin 4
Although there is no problem in the adhesive strength according to No. 5, since both the signal metal pattern (wiring pattern) 43 and the light shielding pattern 44 formed on the back surface are formed of metal, these two patterns 43 and 44 come into contact with each other. A gap 46 must be provided between the signal metal pattern 43 and the light shielding pattern 44 so as not to cause a short circuit (see FIG. 8B). Therefore, since external light enters through the gap 46 and reaches the semiconductor IC chip 42, it is impossible to reliably block light.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and a semiconductor which can reliably perform light shielding on an LSI circuit surface of a semiconductor IC chip while maintaining the adhesive strength between the semiconductor IC chip and a wiring board. It is an object to provide a device.

[0014]

In order to solve the above-mentioned problems, a semiconductor device according to the present invention comprises a semiconductor IC chip mounted on a wiring board having wiring patterns on both surfaces thereof through a conductive adhesive. In a semiconductor device mounted by a mounting method, the wiring pattern is disposed on a mounting-side wiring pattern disposed on a semiconductor IC chip mounting surface of the wiring substrate and on a back surface opposite to the semiconductor IC chip mounting surface. A light-shielding pattern is formed on the semiconductor IC chip mounting surface of the wiring board, the light-shielding pattern being adapted to the pattern of the gap where the back wiring pattern is not arranged, from the back surface of the wiring board to the semiconductor IC chip. It is characterized by being provided so as to block incident light.

According to the above configuration, since the semiconductor IC chip is mounted on the wiring board by the face-down mounting method, the surface of the semiconductor IC chip on which the LSI circuit is formed (hereinafter referred to as the circuit forming surface). ) Is facing the wiring board side. Therefore, when light enters from the back surface of the wiring board, the light is transmitted to the LSI provided on the semiconductor IC chip.
It reaches the circuit and causes malfunction of the LSI circuit, erasure of internal data, and the like. Therefore, as described above, by forming the light-shielding pattern so as to match the pattern of the gap where the back side wiring pattern is not arranged, light incident from the back side of the wiring board can be applied to the circuit formation surface of the semiconductor IC chip. So that it can be reliably shut off.

Since the light-shielding pattern is provided on the side of the wiring substrate on which the semiconductor IC chip is mounted, the light-shielding pattern is smaller than the gap where the backside wiring pattern is not arranged so as to prevent short-circuiting by contacting the backside wiring pattern. It does not need to be formed. Therefore, the light-shielding pattern is formed in accordance with the pattern of the gap, and light leakage can be reliably suppressed.

Further, a resin is generally used for the conductive adhesive, and a metal is said to be effective as a material of the light-shielding pattern. Here, the adhesive strength between the resin and the metal is considerably smaller than the adhesive strength between the resin and a general wiring board material. For example, when using epoxy resin containing glass fiber for the wiring board and using gold for the light-shielding pattern, even when the adhesive strength between the epoxy resin containing glass fiber and the resin is 800 g or more, the adhesive strength between gold and the resin is used. Is 200g
It is about. Therefore, as the bonding area between the conductive adhesive and the wiring board decreases, the bonding strength between the conductive adhesive and the wiring board decreases.

On the other hand, although the light-shielding pattern of the semiconductor device according to the present invention is provided on the side of the wiring substrate on which the semiconductor IC chip is mounted, it is not the same size as the semiconductor IC chip, Since it is provided in accordance with the pattern of the gap portion that is not arranged, it is possible to secure the bonding area between the conductive adhesive and the wiring board as wide as possible. Therefore, sufficient adhesive strength between the wiring substrate and the conductive adhesive can be maintained.

Thus, it is possible to surely shield the circuit forming surface of the semiconductor IC chip from light while maintaining the adhesive strength between the conductive adhesive and the wiring substrate.

Further, in order to solve the above problem, in the semiconductor device of the present invention, it is preferable that the light shielding pattern is formed of the same metal material as the wiring pattern.

According to the above configuration, since the light-shielding pattern is formed of a metal material, external light can be reliably blocked. Further, since the light shielding pattern is made of the same metal material as the wiring pattern, the light shielding pattern and the wiring pattern can be formed in the same step.

As a result, a highly reliable semiconductor device
It can be manufactured at low cost while suppressing an increase in the number of steps.

Further, in order to solve the above-mentioned problem, in the semiconductor device of the present invention, when a region where the semiconductor IC chip is mounted is a mounting region, at least in the mounting region, the light-shielding pattern is formed by the gap portion. It is preferable that the shape is similar to the pattern described above.

According to the above configuration, the light-shielding pattern is provided not in the same shape as the semiconductor IC chip but in the mounting area of the semiconductor IC chip so as to be similar in shape to the pattern of the gap portion. The light incident from the back surface of the device can be effectively blocked with an area as small as possible. Therefore, the bonding area between the conductive adhesive and the wiring board can be as large as possible.

Thus, it is possible to more surely shield the circuit forming surface of the semiconductor IC chip from light while maintaining the adhesive strength between the conductive adhesive and the wiring substrate as much as possible.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a sectional view showing a configuration of a semiconductor device according to the present embodiment.
As in the case of a grated circuit card, a signal metal pattern (wiring pattern) is also provided on the back surface.

As shown in FIG. 1, in the above semiconductor device, a semiconductor IC chip 2 is mounted by a flip-chip mounting method on a wiring board 1 made of glass-fiber-filled epoxy resin provided with signal metal patterns 3 on both sides. It is configured. Further, a light shielding pattern 6 made of metal is provided on the semiconductor IC chip mounting surface (the surface on which the semiconductor IC chip 2 is mounted) 1a of the wiring board 1.

The flip-chip mounting described above refers to the face-down mounting method in which the surface of the semiconductor IC chip on which the circuit is formed and the wiring board are opposed to each other and electrically connected to each other. This is a mounting method in which electrodes are directly connected to wiring electrodes of a wiring board or package.

The LSI (Large) of the semiconductor IC chip 2
Scale Integration) On the circuit forming surface 2a, bumps 4 are provided in advance via pads (not shown). On the other hand, on the semiconductor IC chip mounting surface 1 a of the wiring board 1, a mounting-side signal metal pattern 3 a described later is provided at a position corresponding to the bump 4. The bumps 4 of the semiconductor IC chip 2 are connected to the mounting-side signal metal patterns 3 a on the wiring board 1, and the semiconductor IC chip 2 is mounted on the wiring board 1.

Signal metal patterns 3 are formed on both surfaces of the wiring board 1, respectively. The signal metal patterns 3 are formed on the mounting side signal forming surface 1a of the wiring board 1 on the semiconductor IC chip mounting surface 1a. It comprises a metal pattern 3a and a back side signal metal pattern 3b formed on a surface (hereinafter referred to as a back surface) 1b opposite to the semiconductor IC chip mounting surface 1a.

The mounting-side signal metal pattern 3a is linear (see FIG. 2). The semiconductor IC chip mounting surface 1a of the wiring board 1 is arranged from the vicinity of the bump 4 of the semiconductor IC chip 2 to the semiconductor IC chip. It is formed so as to extend outward from the chip 2.

On the other hand, as shown in FIG. 3, the back side signal metal pattern 3b is formed by arranging a plurality of rectangular partial metal patterns 7 in a tile shape. It has a large area. Since the plurality of partial metal patterns 7 constituting the back side signal metal pattern 3b need to have different signals, each of the partial metal patterns 7 is so contacted that the adjacent partial metal patterns 7 do not short-circuit. A gap portion 8 is provided between 7. The gap 8 has a cross shape, and the back side signal metal pattern 3b is not disposed in the gap 8, so that the wiring board 1 is exposed.

As shown in FIG.
Is provided on the semiconductor IC chip mounting surface 1a of the wiring board 1. As shown in FIG. 2, the light-shielding pattern 6 covers the gap 8 where the back side signal metal pattern 3b is not formed in the mounting area 9 of the semiconductor IC chip 2 indicated by the two-dot chain line in the figure. Is formed. Therefore, the light-shielding pattern 6 has a cross shape like the above-mentioned gap portion 8. As described above, the shape of the light shielding pattern 6 is determined in accordance with the shape of the gap 8 of the back side signal metal pattern 3b. Therefore, if the shape of the gap 8 of the back side signal metal pattern 3b changes, the shape thereof is changed. It is necessary to change the shape of the light-shielding pattern 6 according to the situation.

In other words, in other words, the light shielding pattern 6
Is the shape of the portion where both the mounting side signal metal pattern 3a and the back side signal metal pattern 3b are not formed, that is, the mounting side signal metal pattern 3a and the back side signal metal pattern 3b are overlapped. It can also be considered that it is formed in a cross shape according to the shape of the gap of the signal metal pattern 3 at that time, and covers the gap.

Further, the light-shielding pattern 6 is formed of the same metal material (for example, gold) as the signal metal pattern 3. Since the metal pattern can effectively shield light, the light-shielding pattern 6 can reliably block external light. Further, since the light shielding pattern 6 and the signal metal pattern 3 can be formed in the same step,
An increase in the number of steps can be suppressed, and an increase in manufacturing cost can be suppressed.

Next, a process for mounting the semiconductor IC chip 2 on the wiring board 1 will be described with reference to FIGS. 4 (a) and 4 (b).

First, the mounting-side signal metal pattern 3a and the light-shielding pattern 6 are formed on the semiconductor IC chip mounting surface 1a of the wiring board 1, and the back-side signal metal pattern 3b is formed on the back surface 1b.
To form A cross-shaped gap 8 is formed in the back side signal metal pattern 3b. In the wiring board 1,
An anisotropic conductive adhesive, which is the resin 5, is temporarily pressed at 85 ° C. for about 5 seconds to a region where the semiconductor IC chip 2 is to be mounted in a later step (see FIG. 4A).

Next, the semiconductor IC chip 2 having the bumps 4 formed on the pads (not shown) on the circuit forming surface 2a is connected to the wiring board 1 by the face-down mounting method at a connection temperature of 18.
It is mounted at 0 ° C. for about 20 seconds (see FIG. 4B).

As described above, by providing the light-shielding pattern 6, the light entering from the gap 8 of the metal signal pattern 3b on the back side of the glass fiber-filled epoxy resin wiring board 1 is reduced.
The circuit can be reliably shut off so as not to reach the circuit forming surface 2a of the semiconductor IC chip 2. Therefore, semiconductor IC
It is possible to reliably prevent the LSI circuit of the chip 2 from being illuminated by light and causing the LSI circuit to malfunction or the internal data to be erased.

Further, since the light shielding pattern 6 is formed in accordance with the shape of the gap 8 of the back side signal metal pattern 3b, the area occupied by the light shielding pattern 6 is as small as possible. Therefore, a wide bonding surface between the resin 5 and the glass fiber-containing epoxy resin forming the wiring board 1 can be ensured, so that the bonding strength between the wiring board 1 and the resin 5 can be sufficiently maintained.

By providing the light-shielding pattern 6 in this manner, it is possible to reliably shut off light to the LSI circuit of the semiconductor IC chip 2 while maintaining the adhesive strength between the wiring board 1 and the resin 5. .

The width of the light-shielding pattern 6 is determined by considering the gap between the mounting-side signal metal pattern 3a and the back-side signal metal pattern 3b, light diffraction, and the like. It is desirable that the width be larger than the width of 8 by about 0.2 mm or more.

As described above, according to the semiconductor device of the present invention, in a semiconductor device in which a semiconductor IC chip is mounted face-down on a substrate, the substrate surface on the semiconductor IC chip mounting surface side and the substrate surface on the opposite side to the semiconductor IC chip mounting surface are provided. A light-shielding pattern for shielding the semiconductor IC chip mounting surface from light according to the gap between the metal wiring patterns provided on the substrate surface opposite to the semiconductor IC chip mounting surface. Is provided. Thereby, it is possible to maintain the adhesive strength between the resin provided between the semiconductor IC chip and the substrate and the substrate, and to enable light shielding on the semiconductor IC chip.

[0045]

As described above, in the semiconductor device according to the present invention, the wiring pattern provided on the wiring board is the same as the mounting-side wiring pattern arranged on the semiconductor IC chip mounting surface of the wiring board. A light-shielding pattern formed of a backside wiring pattern disposed on the back surface opposite to the IC chip mounting surface, and on the semiconductor IC chip mounting surface of the wiring substrate, the light-shielding pattern being adapted to a pattern of a gap where the backside wiring pattern is not disposed; Is provided so as to block light incident on the semiconductor IC chip from the back surface of the wiring substrate.

Therefore, light incident from the back surface of the wiring board can be reliably blocked so as not to hit the circuit forming surface of the semiconductor IC chip, and provided between the semiconductor IC chip and the wiring board. The bonding area between the conductive adhesive material and the wiring board can be as wide as possible. As a result, there is an effect that the light-shielding on the circuit forming surface of the semiconductor IC chip can be reliably performed while maintaining the adhesive strength between the conductive adhesive and the wiring substrate.

Further, in the semiconductor device according to the present invention, it is preferable that the light shielding pattern is formed of the same metal material as the wiring pattern.

Therefore, light from the outside can be reliably blocked, and the light-shielding pattern and the wiring pattern can be formed in the same step. Accordingly, a further effect is obtained that a highly reliable semiconductor device can be manufactured at a low cost while suppressing an increase in the number of steps.

Further, in order to solve the above-mentioned problem, in the semiconductor device of the present invention, when a region where the semiconductor IC chip is mounted is a mounting region, at least in the mounting region, the light shielding pattern is formed by the gap portion. It is preferable to adopt a configuration similar to the above pattern.

Therefore, the light-shielding pattern can effectively block the light incident from the back surface of the wiring board with the smallest possible area, so that the bonding area between the conductive adhesive and the wiring board is as large as possible. become. As a result, it is possible to maintain the adhesive strength between the conductive adhesive and the wiring substrate as much as possible, and furthermore, it is possible to more reliably shield the circuit forming surface of the semiconductor IC chip from light.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a semiconductor device according to an embodiment of the present invention.

FIG. 2 is a semiconductor IC of a wiring board in the semiconductor device.
It is a principal part top view on the chip mounting surface side.

FIG. 3 is a plan view of a main part of a back surface side of a wiring board in the semiconductor device.

FIGS. 4A and 4B are process diagrams showing a manufacturing process of the semiconductor device.

FIG. 5 is a cross-sectional view illustrating a configuration of a conventional semiconductor device.

FIG. 6 is a cross-sectional view illustrating a configuration of a conventional semiconductor device.

FIG. 7 is a cross-sectional view showing a configuration of a conventional semiconductor device in which a light-shielding pattern is provided on a side of a wiring substrate on which a semiconductor IC chip is mounted.

FIG. 8A is a cross-sectional view illustrating a configuration of a conventional semiconductor device in which a light-shielding pattern is provided on the back surface of a wiring substrate, and FIG. 8B is a plan view of the wiring substrate viewed from the back surface. is there.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 wiring board 1a semiconductor IC chip mounting surface 1b back surface 2 semiconductor IC chip 3 signal metal pattern (wiring pattern) 3a mounting side signal metal pattern (mounting side wiring pattern) 3b back side signal metal pattern (back side wiring pattern) 5 resin (Conductive adhesive) 6 Light shielding pattern 8 Gap

Claims (3)

[Claims] 1. A semiconductor device in which a semiconductor IC chip is mounted by a face-down mounting method via a conductive adhesive on a wiring board provided with a wiring pattern on both sides, wherein the wiring pattern is formed on the wiring board. A mounting-side wiring pattern disposed on a semiconductor IC chip mounting surface;
A light-shielding pattern which is arranged on the back surface opposite to the C-chip mounting surface and which is arranged on the semiconductor IC chip mounting surface of the wiring board in accordance with the pattern of the gap where the back-side wiring pattern is not arranged; Is provided so as to block light incident on the semiconductor IC chip from the back surface of the wiring substrate. 2. The semiconductor device according to claim 1, wherein said light-shielding pattern is formed of the same metal material as said wiring pattern. 3. A mounting area defined by an area on which the semiconductor IC chip is mounted, wherein at least in the mounting area, the light-shielding pattern is similar to the pattern of the gap. 3. The semiconductor device according to 2.