JPH03262141A - Lead with bump - Google Patents

Abstract

PURPOSE:To facilitate the manufacture of a lead with a bump by a method wherein the bump is constituted into an embossed protrusion of the form of a rice bowl, which is formed the junction surface of the bump to the lead into a projecting surface and is formed the opposite surface to the projecting surface into a recessed surface. CONSTITUTION:A point part of each lead 10, a projecting part 4a of a pressing tool 4 and a hole part 5a of a die 5 are aligned to one another, the lead 10 is pressed and subsided in the hole part 5a of the die 5 by the projecting part 4a of the tool 4 and an embossed protrusion-shaped bump 11 is formed. Then, the tool 4 and the bump 11 are raised from the die 5 in a state that the projecting part 4a of the too 4 comes into contact to the bump 11 and with the die 5 withdrawn from directly under the tool 4, an electrode part 3a on a substrate 1 placed on a block 6 is aligned to the projecting part 4a of the tool 4. Then, the tool 4 is made to descend, the bump 11 is pressed to the electrode part 3a at the point part of each wiring electrode 3 and when a bonding is performed, the lead 10 is connected with the electrode part 3a via the bump 11. Thereby, the formation of the bump is easy, a process ranging from the formation of the bump to the connection of the electrode 3a with the bump can be continuously performed and the cost of the lead with the bump can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a lead with bumps that is bonded to an electrode portion of a semiconductor substrate or a wiring board.

[Prior Art] Conventionally, in order to bond the leads to the electrode portions of a semiconductor substrate or a wiring board, bumps (protrusions) made of soft metal such as solder or gold are provided on the leads in advance, as shown in FIG. ,
There is a bonding method for bonding these bumps and wiring electrodes.

As the bumped lead used in this method,
As shown in FIG. 6, there is an example in which a bump is formed by etching the tip of a lead into a predetermined shape, and in JP-A No. 62'-299
As disclosed in Japanese Patent No. 241, an example is known in which the bonding surface of a bump formed by etching a lead is roughened into a line or mesh pattern.

[Problems to be Solved by the Invention] However, in the above-mentioned bumped leads, in order to form minute bumps at predetermined positions on the leads, it is difficult to accurately attach molten metal droplets to the leads or to etch the leads. However, the disadvantage is that the process becomes complicated and the cost increases. In particular, as recent liquid crystal display elements and semiconductor substrates are becoming increasingly multi-electrode, it is desired to simplify and reduce the cost of connecting electrodes and leads using bumped leads. In addition, the conventional technology has the disadvantage that it is not easy to change the bamboo shape.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a lead with bumps that is easy to manufacture and join, and whose bump shape can be easily changed.

[Means for Solving the Problems] The bumped lead of the present invention has a bump at a predetermined position of the lead for bonding to an electrode portion of a semiconductor substrate or a wiring board, wherein the bump has a bonding surface. It is characterized by a bowl-shaped protrusion with a convex surface and a concave surface on the opposite side.

The method for manufacturing a lead with a bump according to the present invention is characterized in that the lead is punched out using a suppressor having a convex pressing projection having a shape that matches the concave surface to form the punching projection.

The method for joining a lead with a bump according to the present invention is characterized in that after the pressing tool presses out the ejecting protrusion, the suppressing tool is pressed against the electrode portion while being in contact with the concave surface.

[Function] In the bamboo reed of the present invention, since the bump is formed of a bowl-shaped ejected protrusion provided at the tip of the reed, it can be formed by a simple ejecting process and has a feature of high manufacturability.

In addition, when bonding bumps to electrodes, the bonding press can be fitted into the concave side of the bowl-shaped protrusion, so there is no misalignment between the bonding press and the bump, and the pressing force is applied appropriately. It can be conveyed on the surface.

Furthermore, after a bump is driven out by a pressing tool for driving out, if the bump is pressed against an electrode by a pressing tool for driving out while the pressing tool for driving out is in contact with the bump, the contact between the bump and the electrode is improved. There is no need to align the bonding suppressor and the bump during bonding.

[Example] (First Example) An example of the bumped lead of the present invention is partially cut away and shown in FIG.

This bumped lead has a bump 1 formed of a bowl-shaped protrusion that is pressed out at a right angle to the main surface of the lead by a pressing tool at the distal end of the lead 10. Wiring electrodes 3 are provided on the glass substrate 2, and the convex surfaces of the bumps 11 are pressed against the tips of the wiring electrodes 3.

The lead 10 is made of copper foil with a thickness of 35 μm, and a gold plating layer with a thickness of 2 μm is formed on the surface.

The width of the lead 10 is designed to be 125 μm.

The bump 1 has a maximum diameter d of 80 μm and a protrusion height of 30 μm before bonding.

The manufacturing method and joining method of this bumped REET will be described below in the order of FIGS. 2(a) to 2(f).

First, the tip of the lead 10 is aligned with the protrusion 4a of the pressing tool 4 and the hole 5a of the die 5 (see FIG. 2(a)).

Next, the lead 10 is pressed into the hole 5a of the die 5 by the convex part 4a of the pressing tool 4, thereby forming the bump 1 in the shape of a punched protrusion (see FIG. 2(b)).

Next, with the protrusion 4a of the pressing tool 4 and the bumpy 1 in contact with each other, the pressing tool 4 and the bumpy 1 are pulled up from the die 5 (
(See Figure 2(C)).

Next, at the same time as removing the die 5 from directly below the pressing tool 4,
The electrode portion 3a of the substrate 2 placed on the block 6 and the convex portion 4a of the pressing tool 4 are aligned (see FIG. 2(d)).

Next, the pressing tool 4 is lowered and the bump 1 is pressed against the electrode portion 3a at the tip of the wiring electrode 3 for bonding (crimping) (see FIG. 2(e)).

The pressing force at this time is about 20 to 80 CIf, and the pressing time is about 0.1 second. Further, the block 6 is heated, and the substrate 2 is heated to about 250'C.

The pressing tool 4 is heated to the same temperature as the substrate, or heated to 0°2W.
It is also possible to improve the pressure bonding force by adding some degree of ultrasonic vibration.

In conclusion, as shown in FIG. 3 (f>), the lead 1O and the electrode portion 3a are connected by the bumps 11.

Therefore, according to the present invention, it is easier to form bumps than in the past, and since the suppressor 4 can be used both for punching and bonding, processes from bump formation to connection can be performed continuously on one machine. , and costs can be significantly reduced.

(Second example) Another embodiment of the invention is shown in FIG.

FIG. 3(a) shows a lead having a heat-softening resin layer 7 with a thickness of 20 μm on the upper surface of the lead 10a.

FIG. 3(b) shows the process of punching out bumps 11a on leads 10a. In this case, a groove 4b is provided on the outer periphery of the convex portion 4a of the presser 4, and the resin layer immediately below the convex portion 4a of the presser 4 is pressed by heating or applying ultrasonic vibration to the suppressor 4. 7 is pushed out into the groove 4b of the pressing tool 4, thereby smoothing the deformation of the lead portion where the bump 11a is formed. In other words, bumps 11a having a stable shape can be formed. For this purpose, it is also effective to form the tip of the convex portion 4a of the pressing tool 4 into a mountain shape.

Next, FIG. 3(C) shows the state at the time of connection, but the basic factors for connection can be the same as those in FIG. 2(e) described above.

(Third example) Another embodiment of the invention is shown in FIG.

This bumped lead has a bump 91 at the tip of the lead 90, which is a bowl-shaped protrusion that is pressed out by a suppressor at right angles to the main surface of the lead. An aluminum contact electrode 30 is provided on the semiconductor substrate 21 between the interlayer insulating film 22 and the passivation film 23, and is connected to the bump 91.

The lead 90 has a shape in which a 10 μm thick solder layer 93 is formed on a 20 μm thick copper foil 92, and the solder layer 93 side is the bump bonding surface. At the time of bump bonding, it is preferable to heat the pressing tool, the aluminum contact electrode 30, and the lead 90 to such an extent that the solder layer 93 does not melt, so that it is highly deformable. Of course, in this case, it is also possible to apply ultrasonic vibration to the bumps 91.

According to this embodiment, since the lead 90 is constituted by a two-layer film of copper foil 92 and solder foil 93, the bump bonding surface can be deformed without increasing the pressing force during bonding.

Instead of the solder foil 93, a soft metal foil such as gold foil or tin foil may be used. Also, it is naturally possible to use aluminum foil instead of the copper foil 92, and both sides of the copper foil 92 or aluminum foil can be used. It is also possible to laminate a soft metal foil to the laminate, and plating or vacuum deposition can also be used instead of laminate.
Make sure to comb the tip of the leash thinner than the main part.

The bumped leads described above are particularly suitable for face-down mounting of semiconductor pair chips, and are also suitable for TAB (
tape automated bonding)
suitable for In addition, in order to plate solder foil on aluminum foil, for example, the aluminum oxide film is broken by bubbles caused by ultrasonic vibration in a jet soldering bath that holds a silver-containing solder solution, and a three-layer aluminum-silver solder structure is formed. All you have to do is form.

[Effects of the Invention] As explained above, since the bumped lead of the present invention is provided with a bump consisting of a bowl-shaped punched protrusion, it can be formed by a simple punching process, and unnecessary materials and complicated processes are avoided. It has the characteristics of being easy to manufacture without the need for it.

Furthermore, by changing the shape of the pressing tool for punching out bumps, it is possible to easily form bumps with an optimal shape on the lead.

Furthermore, after punching the bump with the pressing tool, if the bump is pressed against the electrode with the pressing tool while keeping the pressing tool and the bump in contact, the positioning of the pressing tool and the bump can be ensured when joining the bump and the electrode. It is possible to bond the bump and the electrode with uniform pressing force.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view showing an embodiment of the bumped lead of the present invention, FIGS. 2 and 3 are process diagrams showing the method of manufacturing and joining the bumped lead of the present invention, and FIG. 4 are sectional views showing other embodiments of the bumped lead of the present invention;
5 and 6 are cross-sectional views of conventional bumped leads. 10... Lead 10 11... Bump 2... Glass substrate (wiring board) 3... Wiring electrode (electrode part)

Claims (3)

[Claims] (1) In a bumped lead having a bump at a predetermined position on the lead for bonding to an electrode portion of a semiconductor substrate or a wiring board, the bump is a bowl-shaped protrusion whose bonding surface is a convex surface and the opposite surface is a concave surface. A bumped reed characterized by being composed of. (2) The method of manufacturing a bumped lead according to claim 1, wherein the lead is punched out using a pressing tool having a convex pressing projection having a shape that matches the concave surface to form the punched out projection. (3) After punching out the punching projection with the pressing tool,
3. The method of joining bumped leads according to claim 2, wherein the pressing tool is pressed against the electrode portion while being in contact with the concave surface.