JP3385533B2 - Semiconductor device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device,
The present invention relates to reduction of electromagnetic noise emission of a flip-chip connection type semiconductor device having a chip capacitor mounted therein, or prevention of malfunction due to electromagnetic noise from the outside.

[0002]

2. Description of the Related Art FIG. 5 is a schematic diagram of a flip-chip connection type semiconductor device in which a conventional chip capacitor is mounted. In this structure, the chip capacitor 3 is mounted horizontally on the interposer 2.

Since the chip capacitor 3 is mounted to reduce power source noise, it is desirable to mount it as close to the semiconductor chip 1 as possible. However, in the case of the interposer 2 which is conventionally used for flip-chip connection in this type of semiconductor device, the area near the semiconductor chip has the highest wiring density, and it is difficult to provide the chip capacitor land in the immediate vicinity of the semiconductor chip. . The procedure for mounting a chip capacitor is to mount the chip capacitor first, then reflow, then mount the semiconductor chip, then reflow the semiconductor chip, and then mount the chip capacitor in the same process, and then reflow all at once. There is a way. In any case, the chip capacitor itself is lightweight and small, and is mounted between the two lands, so
If the reflow temperature varies during reflow, so-called chip rising occurs, and only one electrode may be connected.

[0004]

In the conventional semiconductor device described above, two chip capacitor lands 9 are required for one chip capacitor, a power source and a ground.
Since two chip capacitor lands 9 are required, it is difficult to mount the chip capacitor in the immediate vicinity of the semiconductor chip 1. Although not shown in FIG. 5, when the lid is attached, it overlaps with the attachment portion of the chip capacitor 3 and it is necessary to enlarge the cavity portion of the lid or move the chip capacitor mounting portion to a place further away from the semiconductor chip. is there.

Therefore, an object of the present invention is to incorporate a chip capacitor in a semiconductor device, the chip capacitor is connected between a power supply and ground by an interposer and a lid of the semiconductor device, and the chip capacitor is connected at one end to the interposer and to the other end. Is connected to a lid, and the lid is electrically connected to the ground through an interposer to reduce power supply noise and high frequency noise at the time of operation, which is a problem in a semiconductor device operating at high speed. As another purpose, air holes are provided in the lid to relieve the water vapor pressure stress when assembling the semiconductor device.

[0006]

The semiconductor device of the present invention comprises:
In a flip-chip connection type semiconductor device, a lid and a chip capacitor are mounted, the lid has means for electrically connecting to the ground of an interposer substrate, and the chip capacitor is mounted in a vertical type. Is connected to a power source on the interposer, and the other end is electrically connected to the lid. Further, the lid is characterized by being provided with an air hole.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing a first embodiment of the present invention. As shown in FIG. 1, this embodiment is particularly effective for a semiconductor device that performs flip-chip connection. A semiconductor chip 1 and a plurality of chip capacitors 3 are mounted on the interposer 2. The chip capacitor 3 is connected to the interposer only at one end surface. Although not shown in FIG. 1, the semiconductor chip surface protection and the strength reinforcement are achieved by the underfill resin at the flip-chip connection portion. A conductive paste is applied to the back surface of the semiconductor chip 1 and the other end surface of the chip capacitor 3, and a metal lid 4 is mounted at a position to cover the semiconductor chip 1 and the chip capacitor 3. An air hole 5 is provided in the lid 4.

FIG. 2 is a sectional view of the present invention. The assembly of this semiconductor device is performed as follows. First, the semiconductor chip 1 is mounted on the interposer 2. Next, the chip capacitor 3 is mounted, but it is mounted on the interposer so that only one end surface is connected. Solder is used for connection and fixing. The solder may be applied on the interposer as preliminary solder before mounting, or the chip capacitor may be pre-solder plated. After that, so-called reflow is performed, and the interposer 2, the semiconductor chip 1, and the chip capacitor 3 are electrically connected. Next, the underfill resin 7 is applied and cured. Then, a conductive paste is provided on the back surface of the semiconductor chip 1, the other end surface of the chip capacitor 3, and a part of the interposer 2 (where the lid 4 is in contact with the interposer outside the semiconductor chip and where a power supply pad is provided in advance). 6 is applied, the lid 4 is mounted, and then the conductive paste 6 is fixed.
After that, the solder balls 8 are mounted on the interposer 2, reflowed, and steps such as marking are performed to complete the assembly of the semiconductor device.

FIG. 3 shows a second embodiment of the present invention.
A reinforcing frame called a stiffener 10 is provided between the lid 4 and the interposer 2. The lid 4 is electrically connected in the order of the ground pad of the interposer 2, the stiffener 10 and the lid by using the conductive paste as in the first embodiment. With this structure, the rigidity of the semiconductor device is improved due to the presence of the stiffener 10, so that it can be applied to a larger semiconductor chip. Further, since the area of the lid 4 is increased, the heat dissipation is improved, and the lid 4 can be applied to a semiconductor chip with high heat generation.

FIG. 4 shows a third embodiment of the present invention.
The lid 4 is slightly larger than the outer shape of the interposer 2,
A metal plate processed into a concave shape. The height of the lid 4 is set to be the same as the height of the side of the interposer 2 which is not the mounting surface of the semiconductor chip 1 with the conductive paste 6 having a desired thickness applied to the back surface of the semiconductor chip 1. The chip capacitor 3 is preferably mounted in the immediate vicinity of the semiconductor chip, but it may be mounted on the outer peripheral edge of the interposer 2. Even with this structure, the chip capacitor 3 is mounted vertically. Further, the lid 4 is a solder which is applied to the outer peripheral portion of the interposer or is supplied in the shape of a solder ball when the solder ball 8 is mounted, and is electrically connected to the interposer 2. The feature of this embodiment is that the mounting position of the chip capacitor 3 is highly flexible.

Since both the first and second embodiments are presumed to be mounted in the immediate vicinity of the semiconductor chip,
Although the number of mounted devices is limited, in the third embodiment, since it can be mounted anywhere on the interposer 2, a plurality of devices can be mounted to increase the capacity and chip capacitors with different allowable withstand voltage and frequency characteristics are mounted. Thus, the characteristics of the semiconductor device can be optimized. Moreover, since the area of the lid 4 is large as in the second embodiment, the thermal resistance can be reduced. Further, since the lid 4 is also supported by the chip capacitor 3, even when a large external heat sink (not shown) is mounted on the lid 4, the deformation of the lid 4 can be minimized.

[0012]

As described above, the present invention provides (1)
Since the chip capacitor 3 can be mounted in the immediate vicinity of the semiconductor chip 1, the electric characteristics with respect to power source noise are improved,
(2) The semiconductor chip 1 and the chip capacitor 3 can be fixed by one reflow, which simplifies the manufacturing process. (3) The shape abnormality of the underfill resin fillet due to the mounting of the chip capacitor 3 can be reduced and the connection reliability can be improved. (4) The semiconductor chip 1, the chip capacitor 3, and the lid 4 can be fixed together and electrically connected at the same time, so that the manufacturing process is simplified. (5) The conductive paste 6 The thickness can be reduced and the thermal resistance of the semiconductor device can be reduced. (6) Since the lid 4 is electrically connected to the ground, electromagnetic noise emission at the time of operation of the semiconductor chip 1 is reduced, and conversely electromagnetic waves from outside are reduced. Semiconductor chip 1 due to noise
This has the effect of preventing the malfunction of.

Conventionally, in the case of the interposer 2 used in the flip chip connection in the semiconductor device of this type, the region near the semiconductor chip has the highest wiring density, and the chip capacitor land is provided in the immediate vicinity of the semiconductor chip.
It was difficult. According to the present invention, since the chip capacitor is mounted upright, the mounting land area is half, and the chip capacitor can be mounted near the semiconductor chip. The procedure for mounting the chip capacitor is to mount the chip capacitor first, reflow, and then mount the chip.
There is a method of reflowing, a method of mounting a semiconductor chip and a chip capacitor in the same step as in the present invention, and performing batch reflowing. In any case, the chip capacitor itself is lightweight and small, and it is mounted across two lands, so if there is variation in the reflow temperature during reflow, so-called chip standing occurs and only one electrode is connected. There is. In the present invention, since the chip capacitor is mounted vertically, the solder reflow is originally performed only at one place, a phenomenon such as chip standing does not occur, and there is no need to perform reflow in two steps.

When the chip capacitor 3 is mounted near the chip 1, the underfill resin 7 may be prevented from spreading and, as a result, the fillet shape on the side surface of the semiconductor chip may be wavy. If the fillet shape is not correct, the thermal stress applied to the semiconductor chip may concentrate on the abnormal shape portion, leading to the destruction of the semiconductor chip. In the present invention, the chip capacitor is mounted in the immediate vicinity of the semiconductor chip, but since it is a vertical type, the possibility of hindering the spread of the underfill resin is reduced.

When the lid 4 is attached, the conductive paste 6 is applied to the back surface of the semiconductor chip 1, one end surface of the chip capacitor 3 and the lid ground connection portion on the interposer. Since the conductive paste 6 may be, for example, a silver paste, it can be applied at three locations with one nozzle. After that, the lid 4 is placed at a predetermined position, and a pressing force is applied to uniformly and thinly arrange the back surface of the semiconductor chip. The manufacturing process is easy because it only requires two steps of coating the conductive paste 6 and curing.

In the present invention, an air hole 5 is provided in the lid 4. As a result, even when a material having a high solvent content, that is, a material having a high fluidity is used for the conductive paste 6, it is possible to remove gas during curing. Since the conductive paste has high fluidity, the lid can be pressed to shorten the distance between the back surface of the semiconductor chip and the lid 4, and as a result, the thermal resistance of the semiconductor device can be reduced. Needless to say, the air holes 5 can prevent the interposer from being destroyed and the underfill resin from peeling off due to the water vapor pressure due to the reflow after mounting the solder balls. Lid 4 is interposer 2
Is connected to the ground via. As a result, it is possible to prevent the generation of electromagnetic radiation noise and the intrusion from the outside.

[Brief description of drawings]

FIG. 1 is a schematic view of a semiconductor device showing a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a semiconductor device showing the first embodiment of the present invention.

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

FIG. 4 is a cross-sectional view of a semiconductor device showing a third embodiment of the present invention.

FIG. 5 is a schematic diagram of a flip-chip connection type semiconductor device on which a conventional chip capacitor is mounted.

[Explanation of symbols]

1 semiconductor chip 2 Interposer 3 chip capacitors 4 lid 5 air holes 6 Conductive paste 7 Underfill resin 8 solder balls 9 Land for chip capacitors 10 Stiffener

Claims (6)

(57) [Claims] 1. In a flip-chip connection type semiconductor device, a lid and a chip capacitor are mounted, the lid has means for electrically connecting to the ground of an interposer substrate, and the chip capacitor is mounted vertically. A semiconductor device, wherein one end of the chip capacitor is connected to a power source on the interposer and the other end is electrically connected to the lid. 2. The semiconductor device according to claim 1, wherein a stiffener as a reinforcing frame is inserted between the lid and the interposer. 3. The lid is made slightly larger than the outer shape of the interposer, and a metal plate processed into a concave shape is used. A semiconductor chip is attached to one surface of the interposer so as to be enclosed between the lid and the interposer, 2. The semiconductor device according to claim 1, wherein the height of the lid is the same as the height of the side of the interposer which is not the semiconductor chip mounting surface. 4. The semiconductor device according to claim 3, wherein the lid is a solder supplied by being applied to the outer peripheral portion of the interposer when the solder ball is mounted, and is electrically connected to the interposer. 5. The semiconductor device according to claim 3, wherein the lid is a solder ball-shaped solder supplied to the outer peripheral portion of the interposer when the solder balls are mounted, and is electrically connected to the interposer. 6. The semiconductor device according to claim 1, wherein an air hole is provided in the lid.