JP3947190B2 - Mounting method of semiconductor chip - Google Patents

Description

The present invention relates to a semiconductor chip mounting method and a mounting member thereof, and more particularly to electrode connection in flip chip mounting of a semiconductor bare chip (hereinafter referred to as a semiconductor chip).

In recent years, the electrodes of a semiconductor chip have been made narrower and finer, and the electrode wiring of a mounting member such as an opposing printed wiring board tends to be finer.
In addition, the number of electrode terminals tends to increase due to an increase in the number of I / Os accompanying an improvement in the function of the semiconductor chip.
The electrode of the semiconductor chip is a so-called peripheral (peripheral side) arrangement, which is generally arranged at the peripheral edge of the semiconductor chip. However, with such miniaturization of the electrode and increase in the number of terminals, the electrode shape may be made uniform. It tends to be difficult. Of course, the number of electrodes arranged on each side is not necessarily equal.

When such a semiconductor chip is mounted on a mounting member such as a printed wiring board, the following method has been conventionally employed. (For example, refer to Patent Document 1).
6 and 7 are diagrams showing this prior art. FIGS. 6A to 6C are diagrams showing a semiconductor chip according to a conventional embodiment. FIG. 6A is a top view showing an electrode pad arrangement of a conventional semiconductor chip, and FIGS. 6B and 6C are FIG. 6A.
These are AA sectional drawing and BB sectional drawing.

The semiconductor chip 31 of this conventional embodiment is formed on the outer surface of the semiconductor substrate, and the internal circuit is electrically connected to the electrode 33 formed so that the height from the back surface of the semiconductor substrate is approximately the same. A feature is that a dummy electrode 33d not connected to is added.

6B and 6C, the contact portion between the semiconductor chip electrode 33 and the printed circuit board 32 wiring electrode 34 on the opposite sides of the semiconductor substrate. The total area of each other is equal to each other, and even when connecting by a pressure bonding method such as thermocompression bonding, the pressure applied only to the electrode immediately after the start of thermocompression bonding is equal on opposite sides,
Since it is applied uniformly, there is no difference in the crushing of the electrodes, and uniform connection can be achieved.

7A to 7C show a semiconductor device formed by mounting the semiconductor chip 31 thus formed on the printed circuit board 32 on which the wiring electrode 34 is formed by a flip chip. FIG. 7A is a top view showing an electrode pad arrangement of a semiconductor chip according to a conventional embodiment, and FIGS. 7B and 7C are cross-sectional views taken along line A-A in FIG. It is -B sectional drawing. In FIG. 7A, the printed board 32 is omitted, and only the wiring electrodes 34 of the printed board are shown.

As is apparent from this figure, the electrode 33 of the semiconductor chip 31 and the printed board 3
Since the total contact area of the connecting portion that contacts the two wiring electrodes 34 is equal on the opposite sides, conductive particles (not shown) are included in the adhesive resin 36. Even when connecting with a pressure bonding method such as thermocompression bonding via adhesive, the pressure applied only to the electrode immediately after the start of thermocompression bonding is applied uniformly on the opposite sides, so there is no difference in electrode crushing and uniform connection Can be achieved.

  Here, one connection part on the lower side is indicated by 37, and one connection part on the upper side is indicated by 38.

In addition, in such a semiconductor chip, it is more desirable that the electrodes are arranged in a peripheral manner.

A dummy electrode 33d is formed on the side of the semiconductor chip 31 where the electrode 33 is small, and the contact area can be easily adjusted.

In this way, as shown in FIG. 6A, the area of one connecting portion 37 on the lower side and one connecting portion 38 on the upper side is the connecting portion between the electrode 33 and the wiring electrode 34 of the semiconductor chip 31. Since the number of electrodes is the same, the total contact area on the upper side and the lower side is designed to be equal. In this case, it is necessary to make the upper and lower electrode areas and the left and right electrode areas equal, including the dummy electrodes, at the design stage of the semiconductor electrode. As a result, when flip chip mounting is performed by the thermocompression bonding method, pressure is evenly applied to the electrode connecting portions on opposite sides, so that a uniform mechanical contact is established.

6 pages of JP 2004-193147 A

However, such a conventional semiconductor chip mounting method has a drawback that it cannot be used unless a dummy electrode is formed on the semiconductor chip.
That is, such a method cannot be applied when semiconductor chips that do not have an equal electrode arrangement already exist.

The present invention has been made to solve the above-described problems. That is, this conventional method is sufficient if it is developed retroactively to semiconductor design. Since it cannot be formed, the mounting member can be easily mounted even on a semiconductor chip having no electrode pad on the edge by adopting a solution of forming bumps of the same size on the mounting member on which the semiconductor chip is mounted. It is an object of the present invention to provide a flip chip mounting method that can be mounted on the chip.

The semiconductor chip mounting method according to the present invention is characterized by having the following configuration in mounting a semiconductor chip in which electrode pads formed on the edge are not evenly arranged.
a) forming gold bumps on the electrode pads of the semiconductor chip by wire bonding;
b) An electrode pad is formed at a position facing the gold bump formed in a) on the mounting member for mounting the semiconductor chip.
c) When it is assumed that the electrode pads are uniformly formed on the edge of the semiconductor chip, the electrode pads are formed at positions facing the electrode pads on the mounting member for mounting the semiconductor chip.
d) By wire bonding on the electrode pads on the mounting member formed in c),
Forming gold bumps of almost the same height as the gold bumps formed in a).
e) mounting the semiconductor chip on which the gold bump is formed in a) on the mounting member on which the gold bump is formed in d) by a flip chip mounting method.

In the mounting method of the semiconductor chip according to the present invention, when it is assumed that the electrode pads are formed evenly on the edge of the semiconductor chip, the mounting is performed on the mounting member on which the semiconductor chip is mounted. The formed electrode pad is characterized in that it is not electrically connected to other wiring patterns of the mounting member on which the electrode pad is formed.

In the semiconductor mounting method according to the present invention, the gold wire used in the wire bonding method for forming the gold bump has a diameter of 20 to 30 micrometers and a gold purity of 99.95% or more. Is.

In the semiconductor chip mounting method according to the present invention, it is assumed that the electrode pads are formed evenly on the edge of the semiconductor chip so that the pressing force at the time of flip chip mounting is equally applied to the electrode pads. In some cases, an electrode pad is formed on the mounting member for mounting the semiconductor chip at a position facing the electrode pad.

According to the present invention, since the configuration as described above is adopted, a dummy electrode pad is formed on the mounting member regardless of the number of electrode pads formed on the edge portion of the semiconductor chip. Since gold bumps are formed by wire bonding, and the semiconductor chip is aligned with the mounting member and flip chip mounting is performed, the pressing force is evenly applied to all electrode pads of the semiconductor chip, so the reliability is high. A semiconductor chip can be mounted. Further, since such a configuration is adopted for the mounting member, a mounting member capable of mounting a highly reliable semiconductor chip can be provided.

The best mode for carrying out the present invention will be described with reference to the drawings.
(First embodiment)

In the first embodiment, a surface emitting semiconductor laser chip having only one or two electrodes on a chip, various sensor chips for measuring humidity, temperature, and the like, and a bare chip such as an RFID chip through a gold bump as a substrate The case where it mounts on is demonstrated.
FIGS. 1 to 4 are diagrams for explaining the first embodiment, taking as an example the case of a surface emitting semiconductor laser chip as a chip.

FIG. 1 is a plan view showing an electrode arrangement of a surface emitting semiconductor laser chip, and FIG. 2A is a gold bump having a shape that is sharpened by tearing the tip of the surface emitting semiconductor laser chip by gold wire bonding. FIG. 2 (b) is a plan view when a gold bump is formed by a known method of forming an electrode pad for mounting this chip on a mounting member such as a printed wiring board on which this surface emitting semiconductor laser chip is mounted. A plan view of a mounting member when a wiring pattern is formed and a gold bump is formed,
3A is a diagram in which a sectional view of a mounting member at a position corresponding to the AA sectional view of FIG. 2 is added, and FIG. 3B is a surface emitting semiconductor laser corresponding to the BB sectional view of FIG. FIG. 4 is a diagram showing a state in which a surface emitting semiconductor laser chip is flip-chip mounted on a mounting member.

In FIG. 1, 11 is a surface emitting semiconductor laser chip to be flip chip mounted, 13 is an electrode pad formed on the surface emitting semiconductor laser chip 11, and 18 is a light emitting portion of the surface emitting semiconductor laser chip 11.
In FIG. 2A, reference numeral 13a denotes an electrode pad 1 of the surface emitting semiconductor laser chip 11.
3 is a gold bump formed on 3.

2B and 3B , although not shown in FIG. 2B, 12 is a mounting member such as a printed wiring board, and 14 is a surface-emitting semiconductor to be mounted formed on the mounting member 12. An electrode pad 14d facing the electrode 13 of the laser chip 11 is another wiring pattern formed so that the surface emitting semiconductor laser chip 11 is not inclined when the surface emitting semiconductor laser chip 11 is flip-chip mounted on the mounting member 12. A dummy electrode pad that is not connected, 14dd is a gold bump formed on the dummy electrode pad 14d, and 17 is a wiring pattern drawn from the electrode pad 14.

Next, a method for flip-chip mounting such a surface emitting semiconductor laser chip 11 on the mounting member 12 will be described.
First, a gold bump having a shape whose tip is sharpened by tearing is formed on the electrode pad 13 of the surface emitting semiconductor laser chip 11 by gold wire bonding using a known method. In this case, it is preferable to use a gold wire having a diameter of 20 to 30 micrometers and a purity of 99.95 percent.

Second, an electrode pad 14 is formed on the mounting member 12 at a position facing the gold bump formed on the electrode pad 13 of the surface emitting semiconductor laser chip 11. At the same time,
When it is assumed that the electrode pads are evenly formed on the edge of the surface emitting semiconductor laser chip 11, the electrode pads 1 are positioned on the mounting member 12 so as to face the electrode pads 1.
4d is formed. The electrode pad 14d is a complete dummy electrode that is not connected to other wiring patterns of the mounting member 12. The reason why the dummy electrode 14d is formed in this manner is to apply a uniform load when the surface emitting semiconductor laser chip 11 is mounted on the mounting member 12 as described above, and to prevent tilting during mounting. Then, a predetermined wiring pattern 17 is drawn out from the electrode pad 14. These electrode pads 14 and 14d and the wiring pattern 17 are formed by a known pattern forming method.

Third, a gold bump 14dd is formed on the electrode pad 14d in the same manner as described above. The gold bumps 14dd are formed at substantially the same height as the gold bumps 13a formed on the electrode pads 13 of the surface emitting semiconductor laser chip 11. The formation of substantially the same height in this way makes it possible to apply an equal load to all the gold bumps when the surface emitting semiconductor laser chip 11 is flip-chip mounted on the mounting member 12.
This is because highly reliable mounting is possible. Here, the gold bumps are not formed on the electrode pad 14 because the gold bumps necessary for flip chip mounting are formed on the surface emitting semiconductor laser chip 11 side.

Finally, the surface emitting semiconductor laser chip 11 on which the gold bumps 13a are formed is aligned with the mounting member 12 on which the gold bumps 14dd are formed, overlapped, and flip-chip mounted while applying a predetermined load. As the flip chip mounting method, a known thermocompression bonding method, ultrasonic method, pressure welding method, ACF (anisotropic conductive adhesive tape)
The law etc. can be used. Thus, the mounting of the surface emitting semiconductor laser chip 11 on the mounting member 12 is completed.

In such a semiconductor chip mounting method, when a predetermined load is applied, the gold bumps 14dd formed on the mounting member 12 form the surface emitting semiconductor laser chip 1.
There is a concern that the surface film formed on the surface of 1 may be damaged,
In the case of gold bumps as in the present invention, this is not a problem. The reason is that the compressive yield stress of the gold bump is 400 to 500 MPa at an actual measurement level, and the deformation start stress (yield value) of the gold is the compressive fracture limit stress of the oxide film which is the surface film of the semiconductor chip such as the surface emitting semiconductor laser chip. This is because it is much lower than the value.

Accordingly, since the surface layer film of the surface emitting semiconductor laser chip is not damaged, it goes without saying that no electrical problems such as short circuit and dielectric breakdown occur.
(Second Embodiment)

In the second embodiment, even if an LSI (Large Scale Integrated circuit) having three or more pins is used, a semiconductor chip in which the arrangement of the electrode pads on the four sides is not uniform in the semiconductor chip circuit layout via the gold bump is used as a substrate. The case where it mounts on is demonstrated.
FIG. 5 is a diagram for explaining a second embodiment in such a case.

FIG. 5 is a plan view of a semiconductor chip with nonuniform electrode pad arrangement on the four sides (FIG. 5A).
FIG. 6 is a plan view of a mounting member in which electrode pads and wiring patterns are formed for mounting the semiconductor chip.

In FIG. 5A, reference numeral 21 denotes an LSI of 3 or more, a semiconductor chip in which the electrode pads on the four sides A to D are non-uniformly arranged, and reference numeral 23 denotes the electrode pad. FIG.
, 22 is a mounting member for mounting the semiconductor chip 21, and 24 is the semiconductor chip 2.
1 is an electrode pad for mounting 1, 23 d is a dummy electrode pad for preventing non-uniform pressure when the semiconductor chip 21 is mounted on the mounting member 22, and 27 is a wiring pattern. Since 23d is a dummy electrode pad, there is no wiring pattern. It goes without saying that the dummy electrode pad 23d is formed from the viewpoint as described in the first embodiment.

Such a mounting method of the semiconductor chip 21 on the mounting member 22 is the same as that described in the first embodiment, and therefore the description thereof is omitted. Thus, the semiconductor chip 21 does not tilt during mounting.

It is a top view which shows the electrode arrangement | positioning of the surface emitting semiconductor laser chip which is one embodiment of this invention. 2A is a plan view when gold bumps are formed on the electrodes of the surface emitting semiconductor laser chip of FIG. 1, and FIG. 2B is a chip of a mounting member for mounting the surface emitting semiconductor laser chip. FIG. 2B is a plan view (FIG. 2B) in which electrode pads are formed to mount a wiring pattern, a wiring pattern is formed, and gold bumps are formed. 3A is a diagram in which a cross-sectional view of the mounting member at a position corresponding to the AA cross-sectional view of FIG. 2 is added, and FIG. 3B is a surface light emission corresponding to the BB cross-sectional view of FIG. It is the figure which added sectional drawing of a semiconductor laser chip. It is a figure which shows a mode that the surface emitting semiconductor laser chip of FIG. 1 was flip-chip mounted on the mounting member. It is a figure explaining the 2nd Embodiment of this invention. 6A to 6C are diagrams showing a semiconductor chip according to a conventional embodiment. FIG. 7A is a top view showing an electrode pad arrangement of a conventional semiconductor chip, and FIGS. 7B and 7C are an AA sectional view and a BB sectional view of FIG. 7A. is there.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Surface emitting semiconductor laser chip 12 Mounting member 13 Electrode pad 13a Gold bump 14 Electrode pad 14d Dummy electrode pad 14dd Gold bump 17 Wiring pattern 18 Light emission part 21 Semiconductor chip 22 Mounting member 23 Electrode pad 23d Dummy electrode pad 24 Electrode pad 27 Wiring pattern

Claims (4)

A method of mounting a semiconductor chip, characterized in that, in mounting a semiconductor chip in which electrode pads formed on an edge are not evenly arranged on a mounting member, the following configuration is provided.
a) forming gold bumps on the electrode pads of the semiconductor chip by wire bonding;
b) An electrode pad is formed at a position facing the gold bump formed in a) on the mounting member for mounting the semiconductor chip.
c) When it is assumed that the electrode pads are uniformly formed on the edge of the semiconductor chip, the electrode pads are formed at positions facing the electrode pads on the mounting member for mounting the semiconductor chip.
d) Forming gold bumps of approximately the same height as the gold bumps formed in a) on the electrode pads on the mounting member formed in c) by wire bonding.
e) mounting the semiconductor chip on which the gold bump is formed in a) on the mounting member on which the gold bump is formed in d) by a flip chip mounting method.   2. The method of mounting a semiconductor chip according to claim 1, wherein the electrode pad formed in c) is not electrically connected to other wiring patterns of the mounting member on which the electrode pad is formed.   2. The semiconductor chip mounting according to claim 1, wherein the gold wire used in the wire bonding method for forming the gold bump has a diameter of 20 to 30 micrometers and a gold purity of 99.95% or more. Method.   2. The method of mounting a semiconductor chip according to claim 1, wherein the electrode pads formed in c) are formed so that the pressing force at the time of flip chip mounting is equally applied to each of the electrode pads. Semiconductor chip mounting method.

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