JPH06132353A - Semiconductor device - Google Patents

Abstract

PURPOSE:To correct the deviation of a chip from a board in mounting position through solder reflow in a self-aligned manner in a semiconductor device wherein a semiconductor integrated circuit chip is mounted on a board through flip- chip mounting. CONSTITUTION:Solder bumps 1a provided onto a board 2 and solder bumps 2a provided onto a chip 1 are aligned with each other when the chip 1 is correctly mounted on the board 2, furthermore bumps 11a and 22a shifted deviating from each other by a distance smaller than the diameter of the bump are provided to the chip 1 and the board 2 respectively, and the deviation of the chip 1 is corrected by the surface tension of solder when the bumps are melted.

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, the present invention relates to a device capable of automatically correcting a chip mounting error in flip chip mounting.

[0002]

2. Description of the Related Art Flip-chip mounting means, as shown in FIG. 4 (a), a solder bump 1a is previously formed on an electrode portion (not shown) of a preliminary chip 1 and a preliminary solder (hereinafter Preliminary solder on the board side is also referred to as solder bump) 2a is mounted face down on a conductor portion (not shown) of the board 2 on which the solder bumps 2a are formed, and in this state, they are put in a heating furnace to be joined and soldered together. It is a method.

According to this method, the pitch of the electrode pads is increased as compared with wire bonding and TAB (Tape Automated Bonding) mounting, but wire bonding and TAB are used.
In contrast, the electrode pad can be provided only on the peripheral portion of the chip, whereas the flip chip has the advantage that the pad layout can be eliminated because the pad can be formed at any position on the chip surface. Further, since the chip and the substrate are joined by fine soldering, if a defect is found in the chip after mounting on the substrate, it is possible to easily remove the chip and replace it with a good product, so-called rework.

For this reason, in a multi-chip module in which a plurality of unpackaged chips are mounted in the same package, flip chip mounting, which has good reworkability, is considered to be the mainstream for mounting chips on a substrate. There is. The reason for this is that in a multi-chip module, the overall module yield is the yield of a single chip raised to the power of the number of chips, so it is essential to replace defective chips and improve the overall yield. This is because

[0005]

As described above, the flip-chip mounting has a two-dimensional degree of freedom in the pad layout and is easy to rework, and is superior to wire bonding and TAB. However, it is disadvantageous in terms of bonding cost.

That is, as shown by a broken line in FIG. 4B, it is assumed that the center of the solder bump on the chip side is deviated from the center of the solder bump on the substrate side by an amount corresponding to the diameter of the chip. If it does, the two can no longer be joined. For this reason, in flip chip mounting, it is necessary to detect alignment from both the chip side and the package side (board side) and mount the chip with high accuracy, so a special machine called a flip chip bonder is required. This is a die bonder. It is extremely expensive in comparison. Therefore, a dedicated line is required for flip chip mounting, which increases the bonding cost.

The present invention has been made in order to solve the above-mentioned problems of the conventional one, and an object thereof is to provide a semiconductor device capable of performing flip-chip mounting without using an expensive flip-chip bonder. And

[0008]

A semiconductor device according to the present invention has a center of one solder bump of a pair of a solder bump on the substrate side and a solder bump on the chip side, which are to be formed at positions facing each other. Is formed at a position displaced from the center of the other solder bump by a distance shorter than the diameter of the bump.

[0009]

In the present invention, since the device is constructed as described above, even if the chips are mounted while being deviated due to a mechanical conveyance error, they are formed deviated from each other when the chip and the substrate are bonded. Since the solder bump pair pulls the chip back to the proper position due to the surface tension when the solder bump melts, flip chip mounting is possible without using a flip chip bonder.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 shows a cross-sectional structure of a semiconductor device according to an embodiment of the present invention. In the figure, 1 is a semiconductor integrated circuit chip in which solder bumps are formed on an electrode portion (not shown), and 2 is a solder bump on a conductor portion (not shown). It is a substrate to be processed.

In this embodiment, most of the solder bumps 1a,
In the pair 2a, the solder bump forming position of the semiconductor integrated circuit chip 1 and the corresponding solder bump forming position of the substrate are both regular positions, that is, when the chips are mounted without error, the positions are opposed to each other. Although the solder bumps 11a and 22a are formed at the positions, as shown in FIG. 1 (a), the solder bumps 11a and 22a formed at the positions corresponding to the four corners of the chip are displaced from each other by a distance shorter than their diameter. It is formed so as to be located.

Next, the operation and effect will be described. In the present embodiment, since the device is configured as described above, even if the chip and the substrate are misaligned and mounted due to mechanical mounting accuracy, the reflow of the solder causes the self-alignment effect, and the chip and the substrate are separated. The gap is automatically resolved.

That is, as shown in FIG. 1A, for example, the distance between solder bumps is 200 μm, and the diameter of solder bumps is 1
The gap between the chip and the substrate is 70 to 80 μm.
It is assumed that m is less than or equal to the diameter of the solder bump.

At this time, the displacement of the solder bump pairs 11a and 22a at the four corners of the chip is small due to the mounting displacement,
Most of the solder bump pairs have a large amount of displacement.

In this state, when the chip is mounted on the substrate and placed in a heating furnace to melt the solder, first, since the solder bump pairs at the four corners of the chip have a small amount of deviation between their centers,
The surface tension in the molten state acts so as to move the chip to the right side of the substrate so as to minimize its surface area.

Then, in the majority of the solder bump pairs which had a large amount of displacement until then, the amounts of displacement between the centers of the solder bump pairs at the four corners corrected the chip positions to some extent, so that the solder bump pairs in the melted state. The chip is moved to the right of the substrate so that its surface area is reduced by surface tension as much as possible. As a result, the chip moves in a self-aligned manner toward the proper position, and when the chip reaches the proper position, the force relationship between the solder bump pairs at the four corners and the remaining majority of the solder bump pairs causes this position to change. Stabilizes at. Therefore, it is no longer necessary to mount the chip by the flip chip bonder, and the flip chip mounting can be realized by the inexpensive die bonder without newly installing a dedicated line.

Further, FIG. 1B shows a semiconductor device according to another embodiment of the present invention, which is, for example, a chip of 100 solder bump pairs under the same conditions as FIG. 1A. The deviation amount between the pair of solder bumps 11a and 22a at the four corners is, for example, 80 μm.
m, 10 solder bumps 111a, 22 immediately inside
The shift amount of the 2a pair is, for example, 50 μm, and for the remaining 86, the solder bump pair is formed so as to be positioned at the regular position.

And, by configuring in this way,
Even if the chip is mounted off the substrate, the solder bump pairs at the four corners of the chip pull the chip back toward the proper position, and when this is corrected to some extent, the ten solder bump pairs inside the chip To a more regular position, and finally the majority of the remaining solder bump pairs move the chip to the original position and stabilize in this state.
The chip can be moved to the regular position in a self-aligning manner more smoothly and surely than in the embodiment of FIG.

In this embodiment, two kinds of bumps whose positions are displaced are prepared, but it goes without saying that three or more kinds may be prepared. Further, in each of the above-mentioned embodiments, it goes without saying that the locations where the displaced bump pairs are provided are not limited to the four corners of the chip or the inside thereof.

In each of the above embodiments, the multichip
Although the module has been described as an example, the present invention is not limited to this, and can be applied to all semiconductor devices, and the thermal print head shown in FIGS. 2 (a) and 2 (b) can be used. It should be noted that this can be applied to a device in which a semiconductor device is mounted in addition to the original device, and the same effect as that of the above embodiment can be obtained. In FIG. 2, reference numeral 21 is an alumina ceramic substrate, 23 is a heating resistor formed of a thin film or the like on the substrate 21, and 22 is a control IC for controlling the driving of the heating resistor 23 according to an external signal. The control IC 22 is mounted by flip chip.
Reference numeral 24 is a wiring that connects the control IC 22 and the heating resistor 23.

Further, the mounting on the substrate is not limited to the semiconductor integrated circuit chip, but electronic components such as the hybrid IC shown in FIG. 3 may be mounted, which is similar to the above embodiment. Produce an effect. In FIG. 3, 31 is a substrate made of alumina ceramic, 32 is a substrate 3
1 mounted on the 1 by wire bonding, 33,
34 is a chip component such as a chip capacitor,
1 is mounted by flip chip.

Further, in each of the above-described embodiments, only the case where the chip is mounted on the substrate has been described. However, the chip may be mounted in a package, and the same effect as that of each of the above-described embodiments is obtained.

It is needless to say that the parameters such as the solder bump interval and the number thereof are not limited to those described above in each of the above embodiments.

Needless to say, the mutually offset solder bump pairs in each of the above embodiments may be formed by shifting either the substrate side or the chip side from the normal position.

Further, the mutually displaced solder bump pairs in the above embodiments may be formed by dummy solder bumps that are not connected to the original electrodes.
The same effect as that of each of the above-described embodiments is obtained.

As described above, according to the present invention, in the semiconductor device in which the semiconductor integrated circuit chip is flip-chip mounted on the substrate, the solder bumps on the substrate side and the chip which are to be formed at the positions facing each other. Since the center of one of the pair of solder bumps on the side is displaced from the center of the other by a distance corresponding to a distance shorter than the diameter of the solder bump, a mounting error occurs on the chip. However, this can be corrected in a self-aligning manner, and flip-chip mounting can be realized at low cost.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a thermal print head which is an apparatus to which the present invention can be applied.

FIG. 3 is a diagram showing a hybrid IC that is another device to which the present invention can be applied.

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

[Explanation of symbols]

 1 semiconductor integrated circuit chip 2 substrate 1a, 2a solder bump 11a, 22a solder bump 111a, 222a solder bump

[Procedure amendment]

[Submission date] June 30, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

Claims (1)

[Claims] 1. In a semiconductor device in which a semiconductor integrated circuit chip is flip-chip mounted on a substrate, one of a pair of a solder bump on the substrate side and a solder bump on the chip side to be formed at positions facing each other. The semiconductor device is characterized in that its center is displaced from the other center by a distance corresponding to a distance shorter than the diameter of the solder bump.