JPH04225542A - Semiconductor device - Google Patents

Abstract

PURPOSE:To make easy a fixing workability in a semiconductor device by a method wherein a metallic bump is respectively provided on the semiconductor chip side and the substrate lead side, both metallic bumps are connected by a heat-compressing or by a melt-compressing in a condition that only one bump is melted, and also both the metallic bumps differ in sort and shape. CONSTITUTION:Metallic bumps 5, 6 are respectively formed on a wire 2 of a chip 1 and a lead 4 of a substrate 3, both bumps are connected by a thermo- compression bonding method or a fusion bonding method in a condition that only one metallic bump is melted. The metallic bumps 5, 6 are made of different materials selected from Au, Pd, Pt, Ni, Cu, or their alloys, Pb-Sn, Pb-In, Sn-In or the like, and differ in size and shape.

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 semiconductor device in which a semiconductor chip is attached by a wireless bonding method, particularly a flip chip bonding method or a tape carrier bonding method.

0002

[Prior Art and Problems] Conventionally, as shown in FIG. 8, a semiconductor device mounted via solder bumps has solder bumps 6' attached to either wiring 2' of a semiconductor chip 1' or leads 4' of a substrate 3'. is provided, and the other is bonded to the bump 6' by a thermocompression method or a reflow method for mounting.

However, recently, when a defect occurs in a semiconductor device, repair work is required in which the semiconductor chip 1' is once removed from the substrate 3', the defective part is repaired, and the chip 1' is reattached. In the conventional structure, when the chip 1' is peeled off, the cracks 10' due to thermal fatigue fracture of the bumps 6' occur inconsistently on the substrate 3' side or the chip 1' side, making it troublesome to form bumps when reattaching them. It takes
Or, there is a problem such as not being able to reattach it.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a semiconductor device which eliminates such conventional problems and facilitates repair work of the semiconductor device.

[0005]

[Means for Solving the Problems] In the semiconductor device of the present invention, metal bumps are provided on the semiconductor chip side and the substrate lead side, and both metal bumps are bonded by thermocompression bonding, or only one metal bump is melted. The metal bumps are of different types or have different shapes.

If the reflow method is used as a means for joining the two metal bumps, both bumps will melt and become integrated, and the effects of the present invention cannot be obtained. This is based on the free bonding method.

[0007] There are two ways to use different types of metal bumps. That is, in one embodiment, one of the metal bumps is made of a high melting point metal, such as Au, Pd, Pt, Ni, C.
u or an alloy thereof, and the other is a low melting point metal,
For example, Pb, Sn, In or Pb-Sn,
An alloy such as Pb-In or Sn-In is used.

[0008] In another embodiment, the low melting point metals or the high melting point metals are used as metal bumps, and different metals among the low melting point metals or high melting point metals are combined, including Pb-Sn. , S of Pb-In alloy
This also includes combinations in which the concentrations of n and In are changed.

In this latter aspect, it is desirable to use a combination of low melting point metals or high melting point metals having different hardness and melting point.

[0010] As an embodiment of making the metal bumps irregularly shaped, both metal bumps are made to have different sizes, that is, one bump shape is smaller than the other. Of course, in this variant form of the metal bump, there are a plurality of forms in combination with the different types of bumps, but there is also a form in which both metal bumps are made of the same metal and have shapes that are different in size from each other. It is also good to do this.

[0011]

[Operation] According to the present invention, two metal bumps of different types or irregular shapes provided on the semiconductor chip side and the substrate lead side are joined by thermocompression bonding or by fusion bonding with only one metal bump melted. Breakage during chip peeling always occurs near the bonding interface between both metal bumps.

[0012] Therefore, when the chip is reattached, the newly formed metal bump can be bonded to fill the broken surface of the other metal bump.

[0013]

[Embodiment] An embodiment of the present invention will be described with reference to the drawings. FIGS. 1 and 2 explain the principle and operation of the present invention. 3 is a substrate, and 4 is a lead made of Cu, Al, Ni, etc. formed on the substrate 3. A large number of the wirings 2 and leads 4 are provided on the chip 1 and the substrate 3, but for convenience of explanation, only one corresponding pair is shown.

On the wiring 2 of the chip 1 and on the leads 4 of the substrate 3
On the top, metal bumps 5 and 6 are formed by an arbitrary method such as a wire bonding method (FIG. 1(A)),
Both metal bumps 5 and 6 are joined by thermocompression bonding or fusion bonding with only one metal bump melted (FIG. 1(B)).

The metal bumps 5 and 6 are made of Au, Pd, P
t, Ni, Cu or their alloys, Pb,
Sn, In or their alloy Pb-Sn
, Pb-In, Sn-In, and the like.

When repairing the above semiconductor device, the chip 1
The metal bumps 5 and 6 to be bonded when peeling off from the substrate 3
A crack 10 occurs at or near the bonding interface between the two (FIG. 2(A)), and then new metal bumps 5' are formed on the chip 1 (FIG. 2(B)), and the substrate 3 By thermocompression bonding or fusion bonding with only one of the metal bumps melted, both bumps 5' and 6 are bonded with the bump 5' filling the crack 10 in the metal bump 6.

The above bonding can be performed in the atmosphere, preferably in an inert gas such as N2 gas, by a local heating method such as laser beam heating.

3 to 6 illustrate combinations of metal bumps 5 and 6, and FIG. 3 shows a combination of metal bumps 5 and 6, and FIG.
, Pd, Pt, Ni or an alloy thereof,
Low melting point metals, namely Pb, Sn, In or their alloys Pb-Sn, Pb-In, Sn-In
This shows the combination with etc. FIG. 3(A) shows, as an example, an embodiment of the same shape in which the metal bumps 5 are made of Au and the bumps 6 are made of Sn, and FIG. 3(B) shows an embodiment of a different size in which the metal bumps 5 are smaller than the metal bumps 6. It is.

FIG. 4 shows a combination of metal bumps 5 and 6 made of different types of low melting point metals, and FIG. 4A shows an example in which the metal bumps 5 and 6 are made of Sn and the bump 6 is made of Pb-S.
FIG. 4(B) shows an aspect of the same shape using n, and FIG. 4(B) shows an aspect of the irregular shape.

FIG. 5 shows a combination of metal bumps 5 and 6 made of different types of high melting point metals, and FIG. The shape is shown, and FIG. 5(B) shows the size and size of the irregular shape.

FIG. 6 shows an embodiment in which the metal bumps 5 and 6 are made of the same kind of low melting point metals or the same kind of high melting point metals, and have different sizes.

FIG. 6(A) shows metal bumps 5 and 6 as an example.
Figure 6 (B
) is the case where Au is used for each of the metal bumps 5 and 6.

In the embodiments shown in FIGS. 3 to 6, one of a low melting point metal and a high melting point metal is shown as an example, but other combinations of metal bumps may be freely selected. It is also optional to reverse the metals of 5 and 6.

Furthermore, as shown in FIGS. 4 and 5, when selecting different types of metals from low-melting point metals or high-melting point metals, one should be selected to have a higher melting point or a harder metal than the other. Further, in the embodiment shown in FIG. 6, when the chip 1 is peeled off, the metal bumps 5 and 6 are broken and separated approximately at the bonding interface.

FIG. 7 illustrates another example of the operation in the case of the previous embodiment shown in FIG. 3(B). In the figure, when the chip 1 is peeled off from the substrate 3, destruction occurs at the wiring 2 side of the metal bump 5 or at the bonding interface between the bump 5 and the wiring 2, and part or all of the metal bump 5 is removed from the metal bump 6. (Figure 7(B)). Even in that case, chip 1
When a new metal bump 5' is formed (FIG. 7(C)) and thermocompression bonded onto the substrate 3, the bump 5' pushes the bump 5 on the bump 6 into the bump 6, and the bumps 5, 5' ，
6 becomes integrally joined.

[0026]

[Effect] According to the present invention, when a chip is peeled off to repair a semiconductor device, destruction always occurs near the bonding interface between both metal bumps, so one metal bump maintains almost its bump shape. When reinstalling, it can be bonded to the newly formed bump by thermocompression bonding, or it can be fused and bonded with only one metal bump melted to establish electrical continuity. Therefore, it is possible to provide a repairable semiconductor device and achieve the intended purpose.

[Brief explanation of the drawing]

FIG. 1 is a partially enlarged front view showing bonding of a semiconductor device of the present invention.

FIG. 2 is a front view illustrating the repair action of the present invention.

FIG. 3 is a front view showing an aspect of a metal bump.

FIG. 4 is a front view showing another aspect of the metal bump.

FIG. 5 is a front view showing still another aspect of the metal bump.

FIG. 6 is a front view showing still another aspect of the metal bump.

FIG. 7 is a front view showing another action in the repair of the present invention.

FIG. 8 is a front view showing a conventional example.

[Explanation of symbols]

1 Semiconductor chip
2 Wiring 3 Board
4 Lead 5, 5',
6 Metal bump

Claims

[Claims] 1. Metal bumps are provided on the semiconductor chip side and the substrate lead side, respectively, and both metal bumps are bonded by thermocompression bonding or fusion bonded with only one metal bump melted, and both metal bumps are of different types. or semiconductor devices that are irregularly shaped. 2. The semiconductor device according to claim 1, wherein one of the metal bumps is a high melting point metal bump and the other is a low melting point metal bump. 3. The semiconductor device according to claim 1, wherein the metal bumps have low melting points and are different from each other. 4. The semiconductor device according to claim 1, wherein the metal bumps have high melting points and are different from each other. 5. The semiconductor device according to claim 2, wherein the metal bumps have shapes of different sizes. 6. Both the metal bumps are of the same type,
2. The semiconductor device according to claim 1, wherein the semiconductor device has shapes that are different in size from each other.