JPH0757580A - Transferring conductive bump, conductive bump transferring base material, transferring method for conductive bump - Google Patents

Abstract

PURPOSE:To easily and accurately form an electric circuit or an electric circuit section by providing a transfer section and a plurality of conductive projections not located on the same straight line. CONSTITUTION:Three or more conductive projections 11 having the taper angle of 20 deg. or below and not located on the same straight line are provided on a transfer section 1 having a low-melting point metal layer on the surface to obtain a transferring conductive bump B. The transfer section 1 of the conductive bump B of a conductive bump transfer base material is brought into contact with the electrode section of an object to be transferred, the conductive bump B is heat-pressed to the electrode section 4, then the carrier of the conductive bump transfer base material is peeled from the conductive bump B, and the conductive bump B is transferred and formed on the object to be transferred.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive bump which can be easily and highly accurately formed on an electric circuit or an electric circuit component, a base material for holding the conductive bump, and the conductive bump. And a method of forming the same.

[0002]

2. Description of the Related Art With the progress of technology in recent years, electronic devices have been made lighter and thinner and smaller and smaller. There is a strong demand for dense packaging. 2. Description of the Related Art Conventionally, in this field, a semiconductor element is provided with a protrusion (bump) made of metal to serve as a connection terminal, and mounting is performed by this. Such a mounting method using bumps is useful as a method for improving the mounting density of various electric / electronic components other than semiconductor elements.

However, it is technically difficult to directly form the bump as described above on a semiconductor element or other electric / electronic parts, and there is a problem that it causes a yield in manufacturing electronic equipment.

Therefore, it has been proposed to form bumps on electric / electronic components by a transfer method. However, the method of forming bumps on ITO glass, which is currently mainly used as this transfer method, is still unsatisfactory in terms of manufacturing cost, manufacturing method, bump transfer method, and the like.

In addition, alignment marks on the circuit board are used for alignment when mounting the semiconductor element on the circuit board, but this does not provide sufficient connection reliability.

An object of the present invention is to solve the above problems and to easily and highly accurately form an electric circuit or electric circuit component, and to improve connection reliability in mounting semiconductors and the like. An object is to provide an excellent conductive bump and a base material that holds the conductive bump. Another object of the present invention is to provide a method capable of easily and highly accurately forming a conductive bump on an electric circuit or electric circuit component.

[0007]

SUMMARY OF THE INVENTION The above-mentioned object is the present invention, that is, a transfer conductive bump having a transfer portion and three or more conductive protrusions which are not located on the same straight line. And a self-alignment part that has a conductive protrusion that can penetrate the support and can be detachably held by the support, and that supports the bump-shaped conductive protrusion of the connected body at three or more support points. And a conductive bump for transfer, which has a low melting point metal layer on the surface of the transfer portion,
And a conductive bump transfer base material in which the conductive protrusions of the transfer conductive bump are detachably held by a support, and the conductive bumps of the conductive bump transfer base material are bonded to a transfer target. After that, the method is achieved by a method for transferring conductive bumps, which is characterized in that the support is released.

[0008]

In the above conductive bump for transfer, the bump-shaped conductive protrusions of the connected body are supported at three or more supporting points by the three or more conductive protrusions which are not collinear. Allows self-alignment. In addition, the conductive bump transfer base material in which the conductive protrusions of the bumps are detachably held by the support facilitates the transfer formation of the bumps.

[0009]

EXAMPLES The present invention will be described in detail below with reference to examples. FIG. 1 is a schematic perspective view showing an embodiment of the transfer conductive bump of the present invention. In the figure, B indicates a conductive bump for transfer, which is configured to have a transfer portion 1 and three conductive protrusions 11 which are not located on the same straight line.

In the conductive bump for transfer of the present invention, the transfer portion is bonded to a transfer target such as an electric circuit or an electric circuit component.
On the other hand, three or more conductive protrusions that are not located on the same straight line serve as a connection portion with a bump-shaped conductive protrusion of a connected body such as a semiconductor element.

The conductive bumps for transfer are made of a conductive substance, and as the conductive substance, low melting point metal such as solder, indium, tin, lead, or an alloy made of these is preferably used. . As shown in the schematic sectional view of FIG. 2, the surface of the transfer portion of the conductive bump is made of the low melting point metal 121 as described above, and the other portions are made of the metal 122 other than the low melting point metal. If a two-layer structure is adopted, the low melting point metal 121 on the surface of the transfer portion will bond to the transfer target.
When the transfer is performed, the metal 122 other than the low melting point metal is used.
This is preferable because it can be pressure bonded. As the metal 122 other than the low melting point metal, the low melting point metal 121
On the other hand, a metal having good wettability is preferably used, and examples of such a metal include copper and nickel.

The shape of the transfer portion of the conductive bump is not particularly limited, but a mushroom shape as shown in FIG. 1 is preferable because bonding and transfer to a transfer target can be easily performed.

On the other hand, the conductive protrusions are parts other than the transfer parts of the conductive bumps (for example, the conductive bump B shown in FIG. 1).
Three or more on the same plane), it is preferable that these conductive protrusions are located on the same circumference so that the bump-shaped conductive protrusions of the connected body can be stably supported.

Further, the conductive protrusions have a four-point support type as shown in FIG. 3 in addition to the mode in which the bump-shaped conductive protrusions of the connected body are supported at three points as shown in FIG. However, if the number of protrusions is too large, it becomes difficult to form the protrusions. Therefore, the number of protrusions is preferably 3 to 6.

Further, the conductive protrusion preferably has a shape penetrating the support in order to be detachably held by the support of the conductive bump transfer base material. As the shape of the sex protrusion, for example, as shown in FIG.
A columnar shape, a needle shape, or the like having a specific taper angle as shown in is preferable. The taper angle in this specification means
It refers to the angle α between the length direction and the side surface of the conductive protrusion 11 as shown in FIG. 1. When the conductive protrusion has a taper angle in this manner, the support can be easily peeled off after the conductive bump is bonded to the transfer target, which is preferable. The taper angle is preferably 20 ° or less, preferably about 5 to 15 °. When the taper angle exceeds 20 °, the conductive protrusion may be separated from the support before being transferred, which is not preferable.

As described above, the conductive bumps for transfer have the conductive protrusions releasably held by the support to serve as a conductive bump transfer base material. FIG. 4 is a schematic cross-sectional view showing an example of the conductive bump transfer base material, in which the conductive protrusions 11 of the transfer conductive bump B are held by the support 2.

The support may be any one having electrical insulation and appropriate flexibility, for example, polyester resin, epoxy resin, urethane resin, polystyrene resin, polyamide resin, polyimide resin. ,
ABS resin, polycarbonate resin, silicone resin,
Fluorine-based resins and the like can be mentioned. If a transparent resin is used among these resins, the alignment at the time of bump transfer can be easily performed, and among them, a polyimide resin is preferably used because it has excellent heat resistance and mechanical strength.

The thickness of the support is 5 to 500 μm.
It is preferably about m. When the thickness of the support is less than 5 μm, the heat resistance and mechanical strength of the support become insufficient, while when it exceeds 500 μm, the flexibility of the support becomes insufficient.

In FIG. 4, the conductive protrusion 11 is removably held while penetrating the support 2. However, the conductive protrusion 11 is usually held by the support at the same time when it is formed. That is, a through-hole is formed in the support, and the through-hole is filled with the conductive substance until it protrudes from the opening of the through-hole to form the conductive protrusion and the transfer portion of the conductive bump. At the same time, the conductive protrusion is held by the support.

At this time, the through hole is formed in a shape corresponding to the shape of the conductive protrusion as described above. This through hole is formed by machining, plasma processing,
Laser processing, lithography using a support having photoreactivity, and the like are performed, and the through holes are filled with a conductive substance by a CVD method, a plating method, or the like.

In the above conductive bump transfer substrate,
After the transfer portion of the conductive bump is bonded to the transfer target, the support is separated from the conductive bump, whereby the conductive bump is transferred and formed on the transfer target. FIG. 5 is a schematic diagram showing a method of transferring and forming the conductive bumps.

The conductive bump transfer forming method will be described in more detail with reference to FIG. First, FIG.
As shown in (a), the transfer portion of the conductive bump B of the conductive bump transfer base material S is brought into contact with the electrode portion 4 of the transferred body 3. Here, as described above, when the transfer portion of the conductive bump B has a mushroom shape as shown in FIG. 1, the contact with the electrode portion 4 and the bonding described below can be easily performed.
Then, as shown in FIG. 5B, the conductive bump B is bonded to the electrode portion 4 by thermocompression bonding. Here, since at least the surface of the transfer portion of the conductive bump B is made of the low melting point metal as described above, the thermocompression bonding can be easily performed. After that, as shown in FIG. 5C, the support 2 of the conductive bump transfer base material S is separated from the conductive bumps B.

By the method as described above, the conductive bumps can be easily transferred and formed on the transferred object.

The conductive bump formed by the above method is connected to a connected body such as a semiconductor element. FIG. 6 is a schematic diagram showing this connection method. This connection method will be described below with reference to FIG. First, as shown in FIG. 6A, the bump-shaped conductive protrusions of the connection target are positioned above the conductive bumps formed by the above method on the transfer target. At this time, it is not necessary to strictly align the bump-shaped conductive protrusions of the connected body with the conductive bumps on the transferred body, as long as they are partially overlapped when viewed from above. Then, as shown by the arrow in FIG. 6A, after the bump-shaped conductive protrusions of the connected body are moved in the direct downward direction and brought into contact with the conductive protrusions of the conductive bumps on the transferred body, , Perform alignment by shifting horizontally. After that, as shown in FIG. 6B, the bump-shaped conductive protrusions of the connected body and the conductive bumps on the transferred body are bonded by thermocompression bonding.

In the present invention, as described above, the conductive bumps transferred and formed on the transferred material have three or more conductive protrusions which are not located on the same straight line. As described above, it is possible to easily mount a semiconductor or the like.

As shown in FIG. 7, the conductive bumps of the present invention are transferred and formed on the semiconductor element side, and bump-like conductive protrusions are formed on the electric circuit or electric circuit component side. Good. Also in this case, the semiconductor element or the like can be easily mounted in the same manner as described above.

Further, the conductive bump for transfer, the conductive bump transfer base material and the conductive bump transfer method of the present invention are as follows:
In addition to the mounting of electric / electronic components such as semiconductor elements, the present invention can be applied to a test head for conducting a continuity inspection of the electric / electronic components, a circuit board, etc. and a manufacturing method thereof.

[0028]

In the conductive bumps for transfer of the present invention, self-alignment is performed by three or more conductive protrusions that are not located on the same straight line, and the connection between the bumps and the semiconductor element is more reliable and easy. Has become. Further, since the conductive bump transfer base material of the present invention is such that the conductive protrusions of the conductive bumps are detachably held on the support, the transfer transfer of the bumps is facilitated. There is. Therefore, according to the present invention, the conductive bump can be easily and highly accurately formed on the electric circuit or the electric circuit component, and the semiconductor or the like can be surely and easily mounted.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing one embodiment of a transfer conductive bump of the present invention.

FIG. 2 is a schematic cross-sectional view showing another embodiment of the transfer conductive bump of the present invention.

FIG. 3 is a schematic perspective view showing another embodiment of the transfer conductive bump of the present invention.

FIG. 4 is a schematic cross-sectional view showing an example of a conductive bump transfer base material of the present invention.

FIG. 5 is a schematic cross-sectional view showing an example of a conductive bump transfer method of the present invention.

FIG. 6 is a schematic diagram showing a method of connecting the conductive bumps to the body to be connected.

FIG. 7: Conductive bumps are transferred and formed on the semiconductor element side,
It is a schematic diagram which shows the example which formed the bump-shaped electroconductive protrusion on the electric circuit or the electric circuit component side.

[Explanation of symbols]

 1 Transfer Part 11 Conductive Protrusion Part B Transfer Conductive Bump

Claims (6)

[Claims] 1. A conductive bump for transfer having a transfer portion and three or more conductive protrusions which are not located on the same straight line. 2. The conductive bump for transfer according to claim 1, wherein the conductive protrusion is capable of penetrating the support and being releasably held by the support. 3. The conductive bump for transfer according to claim 1, wherein the conductive protrusion is a self-alignment portion that supports the bump-shaped conductive protrusion of the connected body at three or more supporting points. 4. The conductive bump for transfer according to claim 1, which has a low melting point metal layer on the surface of the transfer portion. 5. A substrate for transfer of conductive bumps, wherein the conductive protrusion of the conductive bump for transfer according to claim 1 is detachably held by a support. 6. A method for transferring a conductive bump, comprising bonding the conductive bump of the conductive bump transfer base material according to claim 5 to a transfer target and then removing the support.