JPS63304587A - Forming method for electrical connection contact - Google Patents

Abstract

PURPOSE:To simplify the forming method for electrical connection contact of a semiconductor chip by using a metallic thin wire gripped by a capillary, and by forming a ball by a ball bonding method, and by forming a bumpy contact of a prescribed shape. CONSTITUTION:A metallic thin wire capable of ball bonding, for example, a gold wire 5 of 25mum in diameter is gripped by a capillary 3 made of a ceramic material or the like, and thermal fusion is used to form a ball 6 on a tip of the gold wire 5. Next, thermal welding or the like is used to fix the ball 6 on an input/output electrode pad 2 of a semiconductor chip 1, so that a bottom part 7 of a bumpy contact of about 80 to 100mum in diameter and of about 35 to 45mum in height is formed. While the gold wire 5 is coupled with the bumpy contact, it is made to pass through a hole 4 of the capillary 3. Next the capillary 3 is moved in the desired direction, that is, in a looped state, so that a bumpy contact of a desired shape can be formed in such a simple process.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for forming electrical connection contacts used to connect an electric microcircuit element, typified by an IC chip, to a group of terminal electrodes on a substrate. .

2. Description of the Related Art Conventionally, soldering has often been used to connect the contact area of an electric microcircuit element to a conductor terminal portion on a circuit board. In recent years, for example, due to the miniaturization of IC flat packages and the increase in the number of connection terminals, the so-called pitch distance between the connection terminals has gradually become narrower, and it has become difficult to solve the problem with conventional soldering technology. In addition, recently there has been a movement to try to use the mounting area more efficiently by directly attaching bare IC chips to electrodes on glass substrates for calculators, electronic watches, liquid crystal displays, etc., and this is an effective alternative to soldering. In addition, a fine electrical connection means is desirable (desired).As a method of electrically connecting a bare IC chip to an electrode on a substrate, a protruding contact (hump) formed on the electrode pad of an IC chip by plating technology is used. A known method for forming protruding contacts is to first form a metal vapor deposition film of Cr, Cu, Au, etc. on the electrode pad on the IC substrate, and then apply a resist. After forming a metal coating of , Cr, Au, etc., the excess resist and metal vapor deposition film are removed to form a protruding contact.

Problems to be Solved by the Invention However, in this method, the method of forming the protruding contacts is quite complicated, requiring a large number of processing steps and advanced etching and plating techniques. Therefore, there is a certain limit to the height of the protruding contacts.

The present invention has been made in view of the above problems, and its object is to provide a method for easily forming an electrical connection contact with a high protrusion through extremely simple steps.

Means for Solving the Problems In order to solve the above problems, the method for forming electrical connection contacts of the present invention involves fixing balls onto the input/output electrode pads of a semiconductor chip using a ball bonding method. , by forming the bottom of the protruding contact, and then integrally forming the top of the loop-shaped or inverted U-shaped protruding contact made of metal wire on the top thereof, the electrical connection contact protrudes in two steps. This is what we are trying to achieve.

Function: According to the above-described method of the present invention, an electric wire with a high protrusion can be formed using a simple process of forming a top made of a metal wire on the top of the bottom of a protruding contact using a ball bonding method. This means that connection contacts can be easily formed.

EXAMPLE Hereinafter, a method for forming an electrical connection contact according to an example of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing an electrical connection contact formed by a method for forming an electrical connection contact in an embodiment of the present invention. Figure 2 (a), (b), (C1, (cl), (e
) are cross-sectional views illustrating a method of forming an electrical connection contact in the order of steps in an embodiment of the present invention. FIG. 3 is a sectional view showing a conventional protruding contact formed by a known plating method.

In FIGS. 1, 2, and 3, 1 is a semiconductor chip;
2 is the input/output electrode band, 3 is the capillary, 4 is the hole, 5 is the gold wire, 6 is the ball, 7 is the bottom of the protruding contact, 8 is the top of the protruding contact, 9 is the protrusion formed by the metal fitting technique It is a contact point.

A method of forming the electrical connection contacts as described above will be explained below with reference to FIGS. 1, 2, and 3.

First, as shown in Fig. 2(a), the hole 4 of the capillary 3 made of ceramic material, artificial ruby, etc. has a diameter of 25 μm.
A gold wire 5 having a diameter of φ is passed through the wire, and a ball is formed at the tip thereof with a diameter approximately 2 to 3 times the diameter of the gold wire 5 using thermal energy such as gas flame or electric discharge.

Next, as shown in FIG. 2(b), the ball 6 formed at the tip of the gold wire 5 is brought into contact with the input/output electrode pad/nod 2 of the semiconductor chip 1 via the capillary 3, and then By fixing it, a bottom part 7 of a protruding contact having an outer diameter of about 80 to 100 μmφ and a height of about 35 to 45 μm is formed.

Next, as shown in FIG. 2(C), with the gold wire 5 connected to the bottom 7 of the protruding contact described above passed through the hole 4 of the capillary 3, the capillary 3 is moved in a loop shape to connect the protruding contact. A top portion 8 having a height of about 65 to 80 μm is formed on the top of the bottom portion 7 . The method is to move the capillary 3 vertically in a loop-like trajectory above the bottom part 7 of the protruding contact as shown in FIG. 2(d), and then move it as shown in FIG. 2(e).
By lowering the capillary 3 and cutting out the gold wire, the top 8 of the protruding contact in the shape of a ring or an inverted U-shape can be formed.

The two-stage protruding electrical connection contact shown in FIG. 1 formed by the above method had an outer diameter of about 80 to 100 μm and a total height of about 100 to 125 μm.

In the embodiment, the material of the metal wire is gold, but the material is not limited to gold, and aluminum, copper, etc. can also be used as long as ball bonding is possible. Further, the wire diameter can be selected depending on the purpose such as the outer diameter and height of the protruding contact to be formed.

Further, there is no particular restriction on the shape of the protruding contact to be formed as long as it is a two-stage protruding shape in which the bottom and top are integrated.

Effects of the Invention As described above, according to the method for forming electrical connection contacts of the present invention, electrical connection contacts are formed on the electrode pad portion of an IC chip using the conventional hole bonding method, so that it is not necessary to use the known plating method. Comparatively, complicated steps are not required and it can be formed extremely easily.

In addition, it is easy to form electrical connection contacts with high protrusions, which is of high practical value.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an electrical connection contact in an embodiment of the present invention, and FIGS.
) is a cross-sectional view showing and explaining the method of forming the electrical connection contact shown in FIG. 1 in the order of steps, and FIG. 3 is a cross-sectional view showing a conventional protruding contact formed by a known plating method. 1... Semiconductor chip, 2... Input/output electrode pad, 3... Capillary, 4...
Hole, 5...Gold wire, 6...Pole, 7...Bottom of the protruding contact, 8...Top of the protruding contact, 9... Protruding contact formed by plating technology. Agent's name: Patent attorney Toshio Nakao Haka1 person 1- Semiconductor chips. 2 --One person93zu7electrodeV・nd8-The top of the engraved shape Fig. 1 Fig. 2 Fig. 3

Claims (1)

[Claims] In forming electrical connection contacts on the input/output electrode pads of a semiconductor chip, there is a process of forming a ball at the tip of a metal wire using thermal energy, and a step of inserting the ball formed at the tip of the metal wire into the semiconductor chip using a capillary. crimping onto the output electrode pad to form the bottom of the protruding contact, moving the capillary in a looped trajectory above the bottom of the protruding contact, and then cutting the metal wire;
1. A method for forming an electrical connection contact, comprising the step of forming the top of a ring-shaped or inverted U-shaped protruding contact using a metal wire.