JPH03129830A - Bump formation - Google Patents

Abstract

PURPOSE:To enhance the workability, productivity, reliability, etc., by a method wherein, after spraying a viscous resin containing flux constituent over an alumi-electrode by an ink-jet mechanism, a metal for making a ball bump is bonded onto the resin to be heated and melted down so that a bump may be formed on the alumi-electrode. CONSTITUTION:A protective film 13 is formed on an alumi-electrode 12 partly opened on a semiconductor substrate 11; a contact metallic layer 14 and a barrier metallic layer 15 are successively formed in the same width as that of the surface of the alumi- electrode 12; and then these elements are processed in the specified areas by a method such as etching process. At this time, a resist film 16 is formed on the contact metallic layer 14 and the barrier metallic layer 15 with the space between the areas C and D in the state of an opening part while a viscous resin 17 containing flux constituent is sprayed over the opening part between the areas C and D by the process such as ink-jetting process, etc., to bond-form a resin film 17. Then, a metallic ball 18 previously formed in specific shape enters the opening part to be processed at the melting down temperature thereof so that a knoll bump 19 may be formed. Through these procedures, both workability and productivity can be enhanced while enabling the bump 19 in excellent economic efficiency and high reliability to be formed without fail.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention is directed to TAB (Tape Automated B)
The present invention relates to a method for forming bumps on semiconductor devices used in semiconductor devices.

(Prior art) Conventionally, as a technology in this field, for example, Japanese Patent Application Laid-open No. 5
There was one described in No. 0-68053.

FIG. 2 is a perspective view illustrating such conventional bump formation.

As shown in this figure, a viscous material dropping device A and a semiconductor chip B on which bumps are to be formed are prepared. Viscous material dropping device A
has a funnel-shaped viscous material storage section 1, with an opening 2 at the top and an outlet 3 at the bottom.

The viscous material storage section 1 is supported by a horizontally movable support 4, and a viscous material pushing rod 5 is provided along the center of the outlet 3 within this storage section 1, and this pushing rod 5 is connected to an arm 6. It is supported by and can be raised and lowered. On the upper surface of the semiconductor chip B, the light emitting elements 7 are arranged in a "h" shape, and around the semiconductor chip 18, electrode pads 8 connected to the light emitting elements 7 are arranged.

Therefore, a conductor paste 9 made by kneading solder powder with flux is put into the viscous material storage section 1, and the outlet 3 of the viscous material dripping device A is aligned above the electrode pad 8 on which a bump is to be formed. is dropped to form a bump IO.

Hereinafter, the formation of the bump will be explained with reference to FIG.

(a) A viscous material extrusion rod 5 is provided at the bottom outlet portion of the viscous material storage section in which the conductive paste 9 is stored, and is positioned directly above the electrode pad 8 on the semiconductor chip B; (b) The viscous material extrusion rod By lowering the rod 5 a certain distance, (c) extruding an appropriate amount of conductor paste 9 to the outside, and immediately after that, by instantly pulling back the viscous material extrusion rod 5, (d) the conductor paste 9 extruded to the outside of the outlet. is dropped onto the electrode pad 8 in the form of droplets of a certain size due to inertia and its own weight.

(Problem B to be Solved by the Invention) However, since the device with the above configuration is a mechanism that moves up and down, there is a possibility that the conductive paste may drip. In addition, since the arm repeatedly moves up and down in the conductor paste, the viscosity of the paste changes rapidly, making it difficult to drop a constant amount of water.In addition, the conductor paste is dripped almost naturally, resulting in a slow bump formation speed. There was a problem.

The present invention eliminates the above-mentioned problems such as dripping of the conductor paste, changes in viscosity, and slow bump formation speed, and uses an inkjet method to adhere resin containing a flux component and supply metal balls to each electrode in bulk. By doing so,
It is an object of the present invention to provide a bump forming method that can improve workability, productivity, reliability, etc.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a bump forming method for forming a bump on an external lead electrode disposed on the main surface of a semiconductor element. A contact metal layer and a barrier metal layer are formed on the electrode, a resist film is formed by opening a part of the metal layer, a sticky resin containing a flux component is adhered to the electrode, and a metal ball is supplied. The bumps are formed by attaching the bumps to the resin and melting the resin by heating.

(Function) According to the present invention, as described above, a sticky resin containing a flux component is sprayed onto an aluminum electrode by an inkjet method, and then a ball-shaped bump composition metal is attached onto the resin, By heating this, it can be melted and a bump can be formed on the aluminum electrode.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view of a bump forming process showing an embodiment of the present invention.

First, as shown in FIG. 1(a), a protective film 13 is formed with a hole formed in a part of the aluminum electrode 12 provided on the semiconductor substrate 11, and a contact is made with the same width as the surface of the aluminum electrode 12. sequentially forming a metal layer 14 and a barrier metal layer 15;
Process these into predetermined areas using methods such as etching,
Shape as shown.

Here, the contact metal layer 14 and the barrier metal layer 1
5, a resist film 16 is formed with holes formed in the area between C and D by photolithography or the like. Subsequently, a sticky resin 17 containing a flux (pine tar (abietic acid)) component is sprayed onto the opening between the areas C and D using an inkjet method or the like to adhere thereto.

Therefore, In, 5nPb, which was processed into a predetermined shape in advance,
, Au Sn, Au Si, etc. metal ball 18
The metal balls 18 are either supplied to the surface of the semiconductor substrate 11 and rolled to be placed into the openings. As a result, Figure 1 (
Adhesively maintain the state shown in a) with the resin 17,
It is attached on top of the aluminum electrode 12 as a material that will become a bump.

Next, as shown in FIG. 1(b), the metal ball 18
is processed at its melting temperature (for example, around 230° C.) to form a circular cone-shaped bump 19.

Note that by changing the distance between the openings C and D of the protective film 13, it is possible to determine whether the tip and cross section of the metal layer 14.15 are exposed to the outside of the bump 19 or included inside.
Either state can be selected. Of course, the number is not limited either.

Furthermore, it goes without saying that various sizes of the metal balls 18 can be selected depending on the size (area), height, etc. of the bumps 19.

The resin 17 acts as a flux and evaporates and disappears when heated. Furthermore, after that, the resist film 16 is dissolved and removed using an organic solvent or the like, and at the same time, the residue of the resin 17 as a flux is removed even more cleanly.

In the above steps, it is preferable that the heat treatment is performed not only during melting but also in an inert atmosphere.

Note that the present invention is not limited to the above embodiments,
Various modifications are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

(Effects of the Invention) As described above in detail, according to the present invention, a sticky resin containing a Franks component is sprayed onto a metal electrode by an inkjet method, and then a ball-shaped bump is formed on the resin. A composition metal can be deposited and melted by heating to form a bump on the metal electrode.

Therefore, workability and productivity in bump formation are improved,
It is possible to reliably form bumps that are economically superior and have high reliability.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a bump forming process showing an embodiment of the present invention;
FIG. 2 is a perspective view illustrating conventional bump formation, and FIG. 3 is a diagram illustrating the bump formation state. 11... Semiconductor substrate, 12... Aluminum electric bridge, 13.
...Protective film, 14... Contact metal layer, 15...
Barrier metal layer, 16... Resist film, 17... Adhesive resin containing Franks component, 18... Metal ball, 19... Bump.

Claims (1)

[Claims] A method for forming bumps on external lead-out electrodes arranged on the main surface of a semiconductor device, comprising: (a) forming a contact metal layer and a barrier metal layer on the external lead-out electrodes; (b) further comprising the steps of: Adhering a sticky resin containing a flux component onto the electrode with a resist film formed by opening a part of the metal layer, (c) supplying a metal ball and adhering it to the resin, (d)
) A bump forming method, which comprises forming bumps by melting the resin by heating.