JP3284890B2 - Bonding method of work with bump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of bonding a bumped work to a bump of a work with a bump, which is bonded to a pad of the work.

[0002]

2. Description of the Related Art In recent years, bumped works have been frequently used as electronic parts (hereinafter referred to as works) such as chips and substrates. Hereinafter, a conventional bonding structure of a work with a bump will be described.

FIG. 8 is a side view of a conventional chip with bumps bonded to a substrate. Reference numeral 1 denotes a substrate as a work, and a pad 2 is formed on an upper surface thereof.
Reference numeral 3 denotes a chip as a work with bumps, and bumps 4 formed on the lower surface thereof are bonded to pads 2 by solder portions 5. In this bonding, after applying a resin 6 as a bond on the substrate 1, the bump 4 is mounted on the solder portion 5 formed on the pad 2, and the solder portion 5 is heated, melted, and solidified. Is thermally cured.

After bonding the bumped chip 3 to the substrate 1, a continuity test is performed to determine whether the bumps 4 are correctly bonded to the pads 2. This continuity test is performed by applying the probe 9 of the tester 8 to the pad 10 of the substrate 1 and applying a current to the chip 3. If it is a non-defective product, the substrate 1 is sent to the next step. In the case of failure, the following repair work was performed. That is, the solder portion 5 is melted again by sending the substrate 1 to a heating furnace and reheating, and the chip 3 with bumps is
Separate from Then, the soldered portions of the substrate 1 and the bumped chip 3 separated from each other are repaired and reused. Of course, in the case of the inexpensive substrate 1 or the work 3 with bumps, there is a case where the substrate 1 is discarded as a defective product without performing the above separation and repair.

[0005]

However, in the above-mentioned conventional repair work, since the solder portion 5 once solidified is reheated in order to melt it, there is a problem that the chip 3 is easily damaged by the reheating. Was. Especially substrate 1
In the case where electronic components other than the chip 3 are mounted, these electronic components are also easily damaged by reheating. After the resin 6 is cured, the continuity test is performed by the tester 8. Therefore, when the repair work is performed, the cured resin 6 must also be peeled from the substrate 1 or the chip 3, and this peeling work is extremely troublesome. There was a problem.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method of bonding a work with bumps, which can easily perform a repair operation in the case of failure in a continuity test after bonding the work with bumps to the work.

[0007]

According to a first aspect of the present invention, there is provided a method of mounting a bumped work on a work by aligning a bump of the work with a bump with the work pad, and performing a heat treatment on the pad. Melting the solder portion to bond the bump on the pad, and forming an alloy layer of the bump and the solder portion, which are dissimilar metals, on the surface of the bump; and conducting a conduction test between the bump and the pad. And, if the result of the continuity test is defective, from the step of breaking the alloy layer by applying vibration to the bumps with a vibrator to separate the workpiece with bumps from the workpiece. A method for bonding a work with bumps was configured.

According to a second aspect of the present invention, a step of applying a resin to the upper surface of the work, a step of aligning the bumps of the work with bumps with the pads of the work and mounting the work with bumps on the work, Melting the solder portion on the pad to bond the bump on the pad, and forming a weak alloy layer of the bump and the solder portion, which are different metals, on the surface of the bump. a step of performing a continuity test of the said bump pad the resin is in an uncured state, not in continuity test
If good, break the alloy layer and work with bumps.
A method of bonding a work with bumps is constituted from the step of separating the work from the work .

[0009]

According to the first aspect of the present invention, a vulnerable alloy layer of a dissimilar metal is formed on the surface of a bump, and when the continuity test results in a failure, vibration is applied to the alloy layer. By doing so, this alloy layer is destroyed, and the work with bumps can be easily separated from the work. In the invention of claim 2,
According to the test, if the continuity test fails, the uncured resin
Work pieces with bumps can be easily separated and repaired.
Can be.

Next, an embodiment of the present invention will be described with reference to the drawings. 1, 2, 3, 4, 5, 6,
FIG. 7 is a bonding step diagram of a work with bumps according to an embodiment of the present invention, which is shown in the order of steps. Hereinafter, a method of bonding a work with bumps will be described with reference to the drawings.

In FIG. 1, pads 12, circuit patterns 13, and pads 14 are formed on the upper surface of a substrate 11. Further, a solder portion 15 is formed on the pad 12. First, the resin 16 is applied to the upper surface of the substrate 11 by the dispenser 17. This resin 16 is thermosetting,
The thermosetting is performed at a temperature higher than the melting point of the solder portion 15. The solder of the solder portion 15 is a low melting point alloy such as tin and lead, and its melting point is, for example, about 200 ° C.

Next, as shown in FIG. 2, the chip 18 is vacuum-sucked to the nozzle 22 of the chip mounter, the bump 19 projecting from the lower surface of the chip 18 is aligned with the pad 12, and the bump 19 is Land on top and mount.
The bump 19 is a metal having a higher melting point than solder, such as gold, silver, or copper.

Next, the substrate 11 is sent to a heating furnace at 220 ° C.
Heat above. Then, the solder portion 15 is melted and the bump 1
On the surface of 9, a thin alloy layer 20 of a metal such as gold, silver or copper as a material of the bump 19 and a metal such as tin or lead as a material of the solder portion 15 is formed. Generally, the alloy layer is weak, and the alloy layer 20 is easily broken by applying vibration as described later.

After bonding the chip 18 to the substrate 11 as described above, a continuity test is performed next. FIG. 4 shows a continuity test, in which a probe 9 of a tester 8 is used.
Is applied to the pads 14 of the substrate 11, and the current conduction state is inspected by the tester 8. At this point, the resin 16 has not been cured. If the continuity test shows a good product,
1 is sent to a heating furnace and heated to thermally cure the resin 16 (FIG. 5). Thus, the bonding of the chip 18 to the substrate 11 is completed.

If the continuity test shown in FIG. 4 indicates a failure, a repair operation is performed by the method shown in FIGS. 6 and 7. That is, as shown in FIG.
1 is pressed to apply vibration to the tip 18. Then, the weak alloy layer 20 is destroyed by this vibration. Thus, the chip 18 can be easily separated from the substrate 11 (FIG. 7).

Since the repair operation is performed in a state where the resin 16 is not cured, the chip 18 can be separated from the substrate 11 without difficulty if the alloy layer 20 is broken as described above.
In this case, since only the thin alloy layer 20 formed on the surface of the bump 19 was destroyed, the chip 18 was damaged as shown in FIG.
When the substrate is separated from the substrate 11, the shape of the bump 19 is not broken, and the shape of the bump 19 is good. Therefore, the chip 18 after the separation can be sufficiently reused. By repairing the resin 16 by removing it, it can be reused. Of course, since the resin 16 is uncured, it can be easily peeled off from the substrate 11 or the chip 13.

The present invention is not limited to the above embodiment. For example, a resin is used as a bond for reinforcing a bonding force. Therefore, if a necessary bonding force can be secured by a solder portion, the resin may not be used. . When a resin is used, the point is that the resin only needs to be uncured when the chip and the substrate are separated as shown in FIG. 7, and therefore, even if the resin is cured at a low temperature equal to or lower than the melting point of the solder. , Which takes a long time to cure,
That is, it may not be cured within the time for performing the steps shown in FIGS. 1 to 7.

[0018]

According to the first aspect of the present invention, by forming an alloy layer of a metal which is a material of the bump and a metal which is a material of the solder portion on the surface of the bump, and applying vibration to the weak alloy layer, Since the work with bumps is separated from the work by destroying the alloy layer, repair work can be performed easily, and the thin alloy layer formed on the surface of the bumps
Breaks the shape of the bumps.
No bumps and good bump shape.
Ru can be fully re-use can work. The invention of claim 2
If the continuity test fails, the uncured resin
Can easily separate the work with
it can. According to the first and second aspects of the present invention, the repair can be performed without heating the work as in the prior art. Therefore, the repair can be performed without damaging the work with bumps or other electronic components mounted on the work. Work can be performed advantageously.

[Brief description of the drawings]

FIG. 1 is a bonding process diagram of a work with bumps according to an embodiment of the present invention.

FIG. 2 is a bonding process diagram of a work with bumps according to an embodiment of the present invention.

FIG. 3 is a bonding process diagram of a work with bumps according to an embodiment of the present invention.

FIG. 4 is a bonding process diagram of a work with bumps according to an embodiment of the present invention.

FIG. 5 is a bonding process diagram of a work with bumps according to an embodiment of the present invention.

FIG. 6 is a bonding process diagram of a work with bumps according to an embodiment of the present invention.

FIG. 7 is a bonding process diagram of a work with bumps according to an embodiment of the present invention.

FIG. 8 is a side view of a bumped chip bonded to a conventional substrate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Substrate (work) 12 Pad 15 Solder part 16 Resin 18 Chip (work with a bump) 19 Bump 20 Alloy layer 21 Exciter

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-8-162499 (JP, A) JP-A-7-211720 (JP, A) JP-A-62-245640 (JP, A) JP-A-6-245640 21117 (JP, A) JP-A-7-7041 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/60

Claims (2)

(57) [Claims] A step of aligning the bumps of the work with bumps with the pads of the work and mounting the work with bumps on the work; and performing a heat treatment to melt a solder portion on the pad and to attach the bump to the pad. Bonding on the bumps and forming an alloy layer of the bumps and the solder portions, which are dissimilar metals, on the surface of the bumps; performing a continuity test between the bumps and the pads; In the case of a failure, a step of breaking the alloy layer by applying vibration to the bumps with a vibrator to separate the work with bumps from the work, Bonding method. 2. A step of applying a resin to the upper surface of the work, a step of aligning the bumps of the work with bumps with the pads of the work, and mounting the work with bumps on the work, Melting the upper solder portion and bonding the bump to the pad;
Of the bump and the solder portion and a dissimilar metal to one another
Causing a weak alloy layer on the surface of the bump;
And performing continuity inspection of the said bump pad the resin is in an uncured state, in the case of failure in the continuity test, the alloy
Break the gold layer and separate the bumped workpiece from the workpiece
And a bonding method for a work with bumps.