JPH04346436A - Bump manufacturing method and device - Google Patents

Abstract

PURPOSE:To provide the bump manufacturing method capable of forming a bump especially having a specific thickness in a bump formation region. CONSTITUTION:During the bump manufacturing method composed of the three steps mentioned as follows i.e., the first melting down step wherein a metallic fine wire drawn out of the end of a capillary 21 is melted down to form a metallic ball 11a; the second press down step wherein the metallic ball 11a is pressed down on a bump formation region 12a provided on the surface of a substrate 12 through the intermediary of the capillary 21; and the third cutting off step wherein the metallic fine wire 11 is torn off in case of isolating the capillary 21 from the bump formation region 12a, before tearing off the metallic fine wire 11, wedge type notches 11c are cut in the outer periphery of the metallic fine wire 11 at specific distance from the bump.

Description

[Detailed description of the invention]

0001

[Industrial Field of Application] The present invention relates to a bump manufacturing method for forming disk-shaped bumps using thin metal wires in the bump forming area of a substrate, and a bump manufacturing apparatus for forming the bumps, particularly for forming disc-shaped bumps with a certain thickness. The present invention relates to a bump manufacturing method and a bump manufacturing apparatus that can form bumps having a large thickness in a bump forming region.

0002

2. Description of the Related Art Next, a conventional bump manufacturing method and a conventional bump manufacturing apparatus will be explained with reference to FIG. Figure 3 shows
FIG. 2 is a sectional side view of a main part in a process order for explaining a conventional bump manufacturing method. In this specification, the same parts, the same materials, etc. are given the same reference numerals throughout the drawings.

[0003] A conventional bump manufacturing method, that is, a bump forming area of a substrate, for example, an electrode 12a of a semiconductor chip 12, is used.
In order to form the disc-shaped bumps 11b (see FIG. 2D) which are metallized to the semiconductor chip 12, first, as shown in FIG. A thin metal wire, for example, a gold (Au) wire 11 containing a small amount of silicon, drawn out from the through hole 21a of a capillary 21 held by an arm (not shown) is melted by hydrogen flame or spark discharge, and the semiconductor chip 12 is melted. A spherical metal ball, that is, a gold ball 11a, is made at the tip of the capillary facing the electrode 12a (FIG. 1(b)).
reference) .

Next, when the bonding arm is advanced in the direction of the semiconductor chip 12 and the capillary 21 held by the bonding arm presses the gold ball 11a against the electrode 12a of the semiconductor chip 12, the gold ball 1
1a is metallically bonded to electrode 12a and is deformed to become a disk-shaped bump 11b (see FIG. 2(c)).

After that, when the gold wire 11 is fixed by a clamper (not shown) constituting the bump manufacturing apparatus and the capillary 21 is separated from the semiconductor chip 12 together with the bonding arm, the heat generated when forming the gold ball 11a is removed. The gold wire 11 is torn off in the vicinity of the bump 11b whose strength has been reduced due to this, and the bump 11b has a stump-shaped remaining gold wire 11d whose wire center is aligned with the separation direction of the capillary 21 and is attached to the semiconductor chip 12. Electrode 12a
(see figure (d)).

Therefore, by repeating this series of operations, a plurality of electrodes 12a of the semiconductor chip 12 can be
This means that bumps 11b can be formed thereon.

[0007]

However, the length H of the remaining gold wire 11d of the bump 11b formed on the electrode 12a of the semiconductor chip 12 by the conventional bump manufacturing method using the conventional bump manufacturing apparatus described above is , it was not constant.

For this reason, there is a problem in that the remaining gold wire 11d is flattened in the direction of the electrode 12a of the semiconductor chip 12, resulting in uneven thickness of the bump 11b whose surface is flattened. The present invention has been made to solve such problems, and its purpose is to provide a bump manufacturing method and a bump manufacturing method capable of forming a bump 11b having a constant thickness on an electrode 12a of a semiconductor chip 12. Our goal is to provide manufacturing equipment.

[0009]

[Means for solving the problem] First objective of the above objectives
(Bump manufacturing method) As shown in FIG. 1, a thin metal wire 11 drawn out from a through hole 21a passing through the tip of a capillary 21 is melted, and a spherical metal is connected to the thin metal wire 11 passing through the through hole 21a. A melting process of forming the ball 11a at the tip of the capillary 21, and
The metal ball 11a is pressed against the bump forming area 12a provided on the surface of the substrate 12 through the metal ball 11a.
In the pressing process, the capillary 21 is deformed into a disk-shaped bump 11b and bonded to the bump forming area 12a, and when the capillary 21 is separated from the bump forming area 12a.
A bump manufacturing method comprising a cutting step of tearing the thin metal wire 11 between the tip of the bump 11b and the bump 11b,
Before tearing the thin metal wire 11, a wedge-shaped notch 11 is formed on the outer peripheral surface of the thin metal wire 11 at a certain distance from the bump 11b.
This is achieved by a bump manufacturing method characterized by making a V-shaped notch (notch).

[0010] The second object of the above objects (bump manufacturing apparatus) is to form a through hole 31a extending from the front end facing the bump forming area 12a provided on the surface of the substrate 12 and a through hole 31a extending from the side surface, as shown in FIG. Side hole 31b leading to 31a
The through hole 31a is held by the bonding arm 32 which alternately moves forward and backward in the direction of the substrate 12.
A capillary 31 from which a thin metal wire 11 is fed out, and a material having a hardness greater than that of the thin metal wire 11, which is movably disposed within a side hole 31b of the capillary 31 and has a wedge-shaped pointed tip directed toward the through hole 31a. It is characterized by comprising a wedge 33 and a wedge driving section 34 that alternately causes the wedge 33 to approach the through hole 31a and move away from the through hole 31a within the side hole 31b according to a predetermined sequence. Achieved by bump manufacturing equipment.

[0011]

[Operation] As shown in FIG. 1, the bump manufacturing method of the present invention involves pulling a fine metal wire, for example, a gold wire 11, connected to a bump formation area on a substrate surface, for example, a bump 11b formed on an electrode 12a of a semiconductor chip 12. Bump 11 before cutting
A notch 11 is formed on the outer peripheral surface of the gold wire 11 at a predetermined distance from b.
I am trying to include c.

[0012] Therefore, when the gold wire 11 with the notch 11c formed on the outer peripheral surface is torn off, the cutting point will be at the notch 11c, so the length of the stump-shaped remaining gold wire 11d explained in FIG. 3 will be the same. H remains constant. Thus, this bump 11b is flattened to form a bump 1 with a flat surface.
1b, its thickness remains constant.

Further, the bump manufacturing apparatus of the present invention is configured such that a wedge 33 with a wedge-shaped pointed end facing the through hole 31a is freely movable within the side hole 31b of the capillary 31, as shown in FIG. ing.

Therefore, the through hole 31 of the capillary 31
Immediately after pressing a gold ball (not shown) formed by melting the gold wire 11 fed out from the capillary 31 onto the electrode 12a of the semiconductor chip 12 with the tip of the capillary 31 to form the bump 11b, the wedge 33 is pressed with the gold wire. When the wedge moves in the direction of the through hole 31a through which the gold wire 11 is passed, the wedge-shaped pointed tip makes a notch 11c in the outer peripheral surface of the gold wire 11.

After that, the gold wire 11 is fixed with a clamper (not shown) and the capillary 31 is separated from the semiconductor chip 12 together with the bonding arm 32.
After being torn off at this notch 11c, the length H of the stump-shaped remaining gold wire 11d explained in FIG. 3 becomes constant. Thus, when this bump 11b is flattened to form a bump 11b with a flat surface, its thickness remains constant.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 is a diagram for explaining an embodiment of the bump manufacturing method of the present invention, FIG. 1(a) to FIG. is an enlarged side view of a main part of a gold wire with a notch in its outer peripheral surface. FIG. 2 is a diagram for explaining an embodiment of the bump manufacturing apparatus of the present invention, in which FIG. 2 (a) is a side sectional view of the main part of the bump manufacturing apparatus, and FIG.
- Figure (d) is a side sectional view of the main part in the process of making a notch in the outer peripheral surface of the gold wire.

An embodiment of the bump manufacturing method of the present invention is similar to the conventional bump manufacturing method explained with reference to FIG.
A thin metal wire, for example, a gold wire 11 containing a small amount of silicon, etc., drawn out from a is melted by hydrogen flame or spark discharge, and a spherical metal ball, that is, a gold ball is placed at the tip of the capillary 21 facing the electrode 12a of the semiconductor chip 12. 11a (see Figure 1(a)).

Next, the capillary 21 is moved toward the semiconductor chip 12 heated to about 200 degrees, and the tip of the capillary 21 presses the gold ball 11a against the electrode of the semiconductor chip 12, for example, the electrode 12a made of an aluminum film. This gold ball 11a deforms as the electrode 1
2a to form a disc-shaped bump 11b firmly adhered to the electrode 12a (see (b) in FIG. 1).
.

Thereafter, the capillary 21 is slightly separated from the semiconductor chip 12 and temporarily stopped without fixing the gold wire 11 with a clamper (not shown). In this state, the two notch forming jigs 22 facing each other with their wedge-shaped tips horizontal are moved in the direction of arrow A, and when the tips of the notch forming jigs 22 press the outer peripheral surface of the gold wire 11, the outer periphery A V-groove-shaped cut, that is, a notch 11c is formed on the surface (see (e) in FIG. 1).

After that, the two notch forming jigs 22 are moved in the direction of arrow A' and returned to their original positions, and then the gold wire 11 is fixed with a clamper, and the capillary 21 is further separated from the semiconductor chip 12. Line 11 is this notch 11
The semiconductor chip 12 will be torn to pieces from c.
The length of the stump-shaped residual gold wire 11d on the surface of the bump 11b formed on the electrode 12a is constant. Thus, this bump 11b is flattened to form a bump 1 with a flat surface.
1b, its thickness remains constant.

Next, an embodiment of the bump manufacturing apparatus of the present invention, which will be described with reference to FIG. 2, is constructed based on a conventional bump manufacturing apparatus. That is, one embodiment of the bump manufacturing apparatus of the present invention has a through hole 31a extending to the tip of the semiconductor chip 12 facing the electrode 12a and a side hole 3 extending from the side surface to the through hole 31a, as shown in FIG.
1b, and is held by a bonding arm 32 that alternately advances and retreats in the direction of the semiconductor chip 12 by a drive device (not shown).
The capillary 31 that feeds out the capillary 31 and the side hole 3 of the capillary 31
The gold wire 11 is made of a material having a hardness greater than that of the gold wire 11 movably disposed within the gold wire 11 with its wedge-shaped pointed end directed toward the through hole 31a, such as an iron-based material having high coercive force characteristics, and is naturally magnetized. A wedge 33 and a gold ball 11a formed by melting a gold wire 11 drawn out from a through hole 31a of a capillary 31 in a predetermined sequence, for example, are connected to the electrode 1 of the semiconductor chip 12 at the tip of the capillary 31.
2a to form the bump 11b, the wedge drive unit 34 alternately causes the wedge 33 to approach the through hole 31a and move away from the through hole 31a within the side hole 31b. It is.

[0022] This wedge drive section 34 includes an electromagnet 34a.
and a power source 34b whose polarity can be freely switched. The electromagnet 34a is disposed outside the wedge 33 in a side hole 31b in which the wedge 33 is accommodated. Therefore, the electromagnet 34a attracts or repulses the wedge 33 in the side hole 31b depending on the polarity of the DC current supplied from the power source 34b, so that the wedge 33
can be freely moved within the side hole 31b.

The power source 34b fixed to the bonding arm 32 also operates a clamper (not shown) that operates the bonding arm 32 and fixes and releases the gold wire 11 passing through the through hole 31a of the capillary 31. Under the control of a central control unit (not shown) that centrally controls the operation, DC current is supplied to the electromagnet 34a while changing the polarity according to a predetermined sequence as described above.

Therefore, in the bump manufacturing apparatus having such a configuration, immediately after the gold ball 11a at the tip of the capillary 31 is formed into a bump 11b on the electrode 12a of the semiconductor chip 12, the power supply 34b supplies the electromagnet 34a with a predetermined polarity. When a direct current is supplied, the wedge 33, which is repelled by the electromagnet 34a, moves vigorously in the direction of the through hole 31a, and its wedge-shaped pointed tip bites into the outer peripheral surface of the gold wire 11 (FIG. 3(b)). and see (c) in the same figure).

After this, the electromagnet 34a is connected to the power source 34b.
When the polarity of the DC current supplied to is reversed, the electromagnet 34a attracts the wedge 33, and the tip of the wedge 33 leaves a notch 11c on the outer circumferential surface of the gold wire 11, separating it from the gold wire 11. (See figure (d))
.

Therefore, in this state, when the gold wire 11 is fixed by the clamper and the capillary 31 is moved together with the bonding arm 32 in a direction away from the semiconductor chip 12, the gold wire 11 is torn off at the notch 11c, as shown in FIG. The length H of the stump-shaped residual gold wire 11d on the surface of the bump 11b described in 3 is constant.

[0027] Thus, this bump 11b is hit flat,
When the bump 11b has a flat surface, its thickness remains constant.

[0028]

As described above, the present invention can provide a bump manufacturing method and a bump manufacturing apparatus that can form bumps having a constant thickness in a bump forming area.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining an embodiment of the bump manufacturing method of the present invention;

FIG. 2 is a diagram for explaining an embodiment of the bump manufacturing apparatus of the present invention;

FIG. 3 is a side cross-sectional view of a main part in a process order for explaining a conventional bump manufacturing method.

[Explanation of symbols]

11 is a gold wire (metal thin wire), 11a is a gold ball (metal ball), 11b is a bump, 11c is a notch, 11d is a remaining gold wire, 12 is a semiconductor chip (substrate), 12a is an electrode (bump formation area), 21 and 31
are capillaries, 21a and 31a are through holes, 31b is a side hole, 22 is a notch forming jig, 32 is a bonding arm, 33 is a wedge, 34 is a wedge drive unit, 34a is an electromagnet, 34b indicate the power supply.

Claims (2)

[Claims] Claim 1: A thin metal wire (11) drawn out from a through hole (21a) passing through the tip of a capillary (21) is melted, and a thin metal wire (11) passing through the through hole (21a) is melted.
11) and a melting step of forming a spherical metal ball (11a) connected to the capillary (11) at the tip of the capillary (21), and providing the metal ball (11a) on the surface of the substrate (12) via the capillary (21). Bump formation area (12a)
a pressing step of deforming the metal ball (11a) into a disc-shaped bump (11b) and joining it to the bump forming region (12a), and separating the capillary (21) from the bump forming region (12a). In the bump manufacturing method, the method includes a cutting step of tearing the thin metal wire (11) between the tip of the capillary (21) and the bump (11b). A method for manufacturing bumps, which comprises making a notch (11c) on the outer peripheral surface of the thin metal wire (11) at a certain distance from the bump (11b) before cutting. 2. A through hole (3) extending through the tip facing the bump forming area (12a) provided on the surface of the substrate (12).
1a) and a side hole (31a) from the side to the through hole (31a)
a capillary (31) that is held by a bonding arm (32) that alternately advances and retreats in the direction of the substrate (12) and feeds out the thin metal wire (11) from the through hole (31a); , a material having a hardness greater than that of the thin metal wire (11), which is movably disposed in the side hole (31b) of the capillary (31) and has a wedge-shaped pointed tip directed toward the through hole (31a). and a wedge (33) that alternately approaches the through hole (31a) and moves away from the through hole (31a) within the side hole (31b) according to a predetermined sequence. A bump manufacturing device comprising: a wedge drive unit (34) for performing the bump manufacturing process.