JP2003121327A - Bonding strength testing machine for bonding wire and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To standardize the bonding strength test of a bonding wire while enhancing reliability. SOLUTION: A gripping block (1), a grip fixture (2) held in the gripping block (1), the cutter (3) held in the gripping block (1) so as to be movable vertically, and a tensile tester 9 connected to the grip fixture (2), are provided to the bonding strength testing machine for the bonding wire. After the bonding wire (5) bonded to the electrode (7) of an electronic part (6) is gripped by the grip fixture (2), the bonding wire (5) is cut by the cutter (3), and the grip fixture (2) gripping the bonding wire (5) is moved upwardly by the tensile tester (9) to measure the strength of the bonding wire (5) and the bonded parts (5a and 5b) of the bonding wire (5).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bonding strength testing device and a bonding strength testing method for measuring the bonding strength of a bonding wire having an end connected to an electrode of an electronic component by wire bonding.

[0002]

2. Description of the Related Art At present, from the viewpoint of productivity and cost, in many cases, electrodes of electronic parts such as semiconductor chips are electrically connected to connection terminals of external leads by bonding wires (thin metal wires). For example, wire bonding is performed by a thermocompression bonding method in which a heated tip of a thin metal wire is pressed against a connected portion or an ultrasonic thermocompression bonding method in which ultrasonic waves are simultaneously applied. The bonding wire is firmly bonded to the electrode, the bonding part shows a stable resistance value for a long time, the loop-shaped bonding wire itself has sufficient mechanical strength, and the bonding wire is not melted by the operating current. This is the quality required for the wire. In particular, if a connection failure occurs at the bonding portion of the bonding wire, the semiconductor device fails to exhibit the desired electrical characteristics, leading to failure. Most of the failures of the semiconductor device result from the connection failure at the bonding portion. Therefore, inspecting the wire bonding and the joint state is very important for supplying a semiconductor device having high quality and stable electrical characteristics, and has been widely performed conventionally.

FIG. 5 shows a conventional bonding strength test method for bonding wires. FIG. 5A shows an electrode formed on the upper surface of a semiconductor chip (6) which is an electronic component.
The state where (7) and the connection terminal (8) of the external lead are electrically connected by the bonding wire (5) at the joint portion (wire neck portion) (5a, 5b) is shown. It is preferable to form the bonding wire (5) from a metal that is chemically stable, has high electrical conductivity and mechanical strength, and has good bondability with the electrode (7). Therefore, for example, gold or aluminum is used as a base metal, and various elements are added in trace amounts as necessary.

When testing the mechanical strength of the bonding wire (5) and the connecting portions (5a, 5b) of the bonding wire (5), first, the bonding wire formed in a loop shape.
The vicinity of the central portion of (5) is cut with a nipper (13) or a cutter, and the bonding wire (5) is opened to expose the cut pieces (5c, 5d) as shown in FIG. 5 (b). Next, the cut pieces (5c, 5d) of the bent bonding wire (5) are respectively pulled outward in the directions of the arrows by using tweezers or the like not shown,
As shown in FIG. 5 (c), the cutting pieces (5c, 5d) of the bonding wire (5) stretched substantially vertically are held by the tip of the jig (12). By a tensile tester (not shown) connected to the jig (12), the jig (12) is pulled upward, the bonding wire (5) is broken or the joints (5a, 5b) are connected to the electrode (7) or the connection terminal (8). ) And the bond strength when peeled off.

[0005]

In the bonding strength test method of pulling and breaking the loop-shaped bonding wire (5) whose both ends are fixed to the bonding portion (5a, 5b), the bonding wire (5) is directly Since the cutting is performed with the nippers (13) or the like, an external force is applied to the joint (5a) with the electrode (7) and the joint (5b) with the connection terminal (8) through the bonding wire (5).
After cutting, when pulling up the bonding wire (5) in a state where it can be easily grasped by the jig (12), an external force is similarly applied to each joint (5a, 5b). In this case, the reason why the bonding strength of the bonding wire (5) to which a tensile force is applied by the tensile tester is low is the effect of cutting or pulling up the bonding wire (5), or the bonding portion (5a, 5b) of the semiconductor device. It is difficult to determine whether it is due to the improper joining, and proper test data cannot be obtained. The same applies when the bonding wire (5) itself is damaged for some reason.

Further, in the above-mentioned bonding strength test method, the loop-shaped bonding wire (5) is cut, after cutting, the bonding wire (5) is stretched, and the cut pieces (5c, 5d) are cut.
It is necessary to prepare the test before gripping the nipper (13), tweezers and jig (1
Since the tester manually conducts the test preparation process using 2) while visually observing with a microscope, it takes a lot of labor and time, which is not preferable in terms of work efficiency.

Therefore, the present invention provides a bonding wire bonding strength testing device and a bonding strength testing method capable of always measuring bonding strength of a bonding wire under the same conditions and obtaining highly reliable measurement data. With the goal. Another object of the present invention is to provide a bonding strength test apparatus and bonding strength test method for a bonding wire, in which a strength test is smoothly prepared by continuous operation to reduce the test time and labor. A further object of the present invention is to provide a standardized bond strength test device and bond strength test method for bonding wires that can be performed without applying unnecessary external force to the bonding wires.

[0008]

A bonding strength testing apparatus for a bonding wire according to the present invention comprises a gripping block (1),
Grip jigs (2, 4) held in the grip block (1)
A cutter (3) held in the grip block (1) so as to be vertically movable, and a tensile tester (9) connected to the grip jigs (2, 4). After gripping the bonding wire (5) fixed to the electrode (7) of the electronic component (6) with the grip jigs (2, 4), the bonding wire (5) is cut by the cutter (3).
Since it is cut, without applying excessive external force to the bonding wire (5) with the bonding wire (5) fixed,
A part of the bonding wire (5) can be cut by the cutter (3) to open the loop. Further, the grip jig (2, 4) holding the bonding wire (5) is moved upward by the tensile tester (9) to move the bonding wire (5) and the bonding portion (5a, 5b) of the bonding wire (5). Since the strength is measured, following cutting, the grip jigs (2, 4) are moved above the bonding portions (5a, 5b) of the bonding wires (5) to continuously and smoothly operate the tensile tester (9 ) To join (5a, 5b)
The bonding strength of can be measured. The measurement of the joint strength of the joints (5a, 5b) means the measurement of the peel strength of the joints (5a, 5b) or the tensile strength of the bonding wire (5) itself.

In the embodiment of the present invention, the grip jig
(2, 4) is a pair of elastic arms (2a, 2b, 4a, 4
b) and a holding part (2c, 4c) which is provided at each tip of the arm part (2a, 2b, 4a, 4b) and holds the bonding wire (5).
And a holding drive device (2d) that brings one of the arm portions (2a, 4a) closer to the other. The cutter (3) includes a blade (3a) for cutting the bonding wire (5) and a cutting drive device for moving the blade (3a) toward the bonding wire (5).
And (3b).

The strength test method of the bonding wire according to the present invention comprises the steps of gripping the bonding wire (5) having both ends fixed by the joints (5a, 5b) with the grip jigs (2, 4) and the grip jig ( The process of cutting the bonding wire (5) gripped by 2, 4) by the cutter (3) and the gripping jig (2, 4) while gripping the cut bonding wire (5) by the grip jig (2, 4). 4) moving the bonding portion (5a, 5b) in a direction substantially opposite to that in which a tensile force is applied to the bonding wire (5), and the bonding wire (5) breaks or the bonding portion (5a, 5b) due to the tensile force. ) Is peeled off, the tensile tester (9) connected to the grip jig (2, 4) is used to measure the tensile strength of the bonding wire (5) or the peeling strength of the joints (5a, 5b). Including.

In the embodiment of the present invention, the joint portions (5a, 5b)
The cut piece (5) of the bonding wire (5)
Grasp c) with the grip jig (2), and use the tensile tester (9) to pull the bonding wire (5) in tensile strength or the joints (5a, 5b).
After measuring the peel strength of one of the bonded parts (5a, 5b), the cutting piece (5d) of the bonding wire (5) connected to the other of the bonding parts (5a, 5b) is held by the grip jig (2), and the tensile tester (9 ), The tensile strength of the bonding wire (5) or the peel strength of the other part of the joint (5a, 5b) may be measured. Also, the process of gripping the bonding wire (5) with the first and second grip jigs (2, 4) and the bonding wire (5) between the first and second grip jigs (2, 4) In the process of cutting in 3) and while gripping each cut piece (5c, 5d) of the cut bonding wire (5), move the first and second grip jigs (2, 4) simultaneously or separately. The process of applying tensile force to the bonding wire (5) and
When (5) breaks or the joints (5a, 5b) peel off, the first
And a tensile tester connected to the second grip jig (2, 4)
The step (9) may include a step of measuring the tensile strength of the bonding wire (5) or the peel strength of the joints (5a, 5b).

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a bonding strength test apparatus for a bonding wire and a bonding strength test method according to the present invention will be described with reference to FIGS. The bonding wire bonding strength test apparatus according to the present embodiment shown in FIGS. 1 and 2 grips a bonding wire (5) having an end connected to an electrode (7) of a semiconductor chip (6) which is an electronic component. A grip jig (2) and a cutter (3) that moves vertically to cut the loop-shaped bonding wire (5) are held in the box-shaped grip block (1). The grip jig (2) includes arm portions (2a, 2b) in which a pair of elongated plate-like members are arranged substantially in parallel.
And bonding wires at the tips of the arms (2a, 2b).
A holding part (2c) for gripping and fixing (5) is provided, and is formed of an elastic member made of metal or resin. As shown in FIG. 2, in order to concentrate the gripping force of the bonding wire (5), the arms (2a, 2a, 2a, 2
b) is a taper-shaped gripping bonding wire
In order to prevent the (5) from falling off, the tips of the arm portions (2a, 2b) are made to face each other and project inward. However, the total amount of inward projection at each tip is smaller than the diameter of the bonding wire (5). Further, the arm portions (2a, 2b) are arranged such that one arm portion (2a) is brought closer to the other arm portion (2b), and the holding portion (2c)
Bonding wire (5)
A gripping drive device (2d) for gripping is provided in the grip block (1). The clamping drive device (2d) is composed of a solenoid (2e) equipped with a plunger (2f) .When the solenoid (2e) is energized, the plunger (2f) resists the elasticity of one arm (2a) and Since the side part of the arm part (2a) is pressed toward the other arm part (2b), the arm part (2a, 2b) can elastically grip the bonding wire (5) at the tip.

The cutter (3) is a blade portion (3a) for cutting the bonding wire (5) held by the grip jig (2).
And a cutting drive device (3b) for moving the blade portion (3a) substantially vertically toward the bonding wire (5). As shown in FIG. 1, as the cutting drive device (3b), for example, a rack (3c)
And a pinion (3d) is formed in the grip block (1), and the pinion (3d) is operatively connected to the motor through a reduction gear (not shown). The pinion (3
The d) can be rotated in the normal and reverse directions to move the cutter (3) together with the blade (3a) in the vertical direction. In the present embodiment, a cutter (3) having one blade portion (3a) is shown, but other cutting instruments such as scissors having two blade portions and cutting the bonding wire (5) by shearing force are used. The included cutter (3) can also be used. The grip jig (2) grips the vicinity of the cutting piece (5c) of the bonding wire (5) by the tensile tester (9) connected to the end of the grip jig (2) opposite to the holding part (2a, 2b). )
Can be pulled vertically upward together with the grip block (1) to measure the bonding strength of the bonding wire (5) and one of the bonding portions (5a). The bonding strength test apparatus for the bonding wire according to the present embodiment has a grip jig (2) for gripping the bonding wire (5) and a grip jig (2).
The cutter (3) that cuts the bonding wire (5) in the gripping state by and the tensile tester (9) that can measure without changing the gripped state before cutting are provided as a single device. Unlike the conventional example of FIG. 5 in which the test preparation is performed, the bonding strength can be smoothly measured in a short time after cutting.

FIG. 3 shows a bonding wire strength test method according to the present embodiment using the above-described bonding strength test apparatus. First, as shown in Fig. 3 (a), each joint (5a, 5a
b) holds the bonding wire (5) fixed to the electrode (7) of the semiconductor chip (6) and the connection terminal (8) of the external lead with the grip jig (2). FIG. 3A shows the same state as FIGS. 1 and 2. Next, as shown in FIG. 3 (b), the cutter (3) is lowered almost vertically from the grip block (1) to cut the bonding wire (5) gripped by the grip jig (2).
At this time, since the bonding wire (5) is completely supported and fixed by the grip jig (2), an excessive external force or an external force is applied to the bonding wire (5) and one of the joints (5a) connected to the electrode (7). No load is applied. After cutting, while gripping the cut piece (5c) of the bonding wire (5) connected to the one joint part (5a) with the grip jig (2), the grip jig (2) is connected to the one joint part (5a). It is moved upward in the substantially opposite direction, and then, as shown in FIG.
As shown in, a tensile force is applied to the bonding wire (5). In the present embodiment, after cutting, since it is not necessary to move and deform the bonding wire (5) to a position and a state where it can be easily grasped, an extra external force is not applied to one joint portion (5a) before the test, and The bonding strength test can be performed without re-holding the bonding wire (5). Figure 1
As shown in, the tensile tester (9) connected to the grip jig (2) is operated to pull up the grip jig (2) at a predetermined speed. As a result, as shown in FIG. 3 (d), the bonding portion (5
A) is peeled off or the bonding wire (5) is broken, and the tensile peel strength or the tensile breaking strength can be measured as the bonding strength by a tensile tester (9) connected to the grip jigs (2, 4). After that, the cutting piece (5d) of the bonding wire (5) connected to the other joint portion (5b) is gripped by the grip jig (2), and the other joint portion (5b) is pulled by the tensile tester (9). Measure the peel strength or the tensile breaking strength of the bonding wire (5).

Since it is necessary to newly hold the bonding wire (5) when measuring the bonding strength of the other bonding portion (5b), as shown in FIG. 4, the first and second grip jigs ( 2, 4) may be provided. In the strength testing method for the bonding wire (5) using the bonding strength testing device shown in FIG. 4, first, each pair of arm portions (2a, 2b, 4a) of the first and second grip jigs (2, 4) is first tested. , 4b) holding part (2c, 4c)
Then, the vicinity of the central portion of the loop-shaped bonding wire (5) is gripped. Next, the bonding wire (5) between the holding parts (2c, 4c) is cut by the cutter (3) arranged between the first and second grip jigs (2, 4). At this time, the cutter (3)
Since both sides of the are held by the grip jigs (2, 4), no load is applied to the joints (5a, 5b) at both ends through the bonding wire (5). After cutting, with the grip jig (2, 4),
Each cut piece (5c, 5d) of the cut bonding wire (5)
While gripping, the first and second grip jigs (2, 4) are moved by the tensile tester (9) connected as shown in FIG. When the tensile tester (9) is connected to both the first and second grip jigs (2, 4), they are moved at the same time. Only one of the first and second grip jigs (2, 4)
When the tensile tester (9) is connected, after moving one, the connection is switched to move the other. Tensile tester
(9) pulls up the first and second grip jigs (2, 4) to apply a tensile force to the bonding wire (5), so that the bonding wire (5) is broken or its joints (5a, 5b) are Tensile strength of the bonding wire (5) at the time of peeling or the joint
Measure the peel strength of (5a, 5b).

[0016]

As described above, the bonding strength test apparatus and the bonding strength test method for the bonding wire according to the present invention reduce unnecessary load applied to the bonding wire and the bonding portion before the test, and always under the same conditions. The bonding wire and its bonding portion can be measured, and a highly reliable strength test result can be obtained. Further, the operations of cutting the bonding wire and performing the strength test can be smoothly transferred, so that the bonding strength test can be made uniform and standardized, and the workability can be improved.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of a bond strength test apparatus according to the present invention.

FIG. 2 is a partially enlarged perspective view of the bond strength testing device shown in FIG.

FIG. 3 is a process diagram showing an embodiment of a strength test method according to the present invention.

FIG. 4 is a perspective view showing another embodiment of the bonding strength test apparatus according to the present invention.

FIG. 5 is a process diagram showing an embodiment for carrying out a conventional bonding strength test method.

[Explanation of symbols]

(1) ・ ・ Gripping block, (2) ・ ・ Grip jig (first grip jig), (2a, 2b, 4a, 4b) ・ ・ Arm part,
(2c, 4c) ・ ・ Holding part, (3) ・ ・ Cutter, (3a) ・ ・ Blade part, (3b) ・ ・ Cutting drive device, (4) ・ ・ Second grip jig, (5) ・ ・Bonding wire, (5a, 5b)
・ Joints, (5c, 5d) ・ ・ Cut pieces, (6) ・ ・ Electronic parts (semiconductor chips), (7) ・ ・ Electrodes, (9) ・ ・ Tensile tester,

Continued front page    F-term (reference) 2G061 AA01 AB01 BA04 CA01 CB02                       CC01 EA01 EB03                 5F044 JJ00

Claims (5)

[Claims] 1. A gripping block, a grip jig held in the grip block, a cutter held in the grip block so as to be vertically movable, and a tensile tester connected to the grip jig. Comprising, after holding the bonding wire fixed to the electrode of the electronic component by the grip jig, the bonding wire is cut by the cutter, and the grip jig holding the bonding wire is moved upward by the tensile tester. A bonding strength test apparatus for bonding wire, wherein the strength of the bonding wire and the strength of the bonding portion of the bonding wire are measured. 2. The grip jig comprises a pair of elastic arm portions, a holding portion which is provided at each tip of the arm portions and holds the bonding wire, and one of the arm portions approaches one of the other. The bonding wire bonding apparatus according to claim 1, further comprising: a clamping drive device that causes the bonding wire to be cut, and a cutting drive device that moves the blade part toward the bonding wire. Strength test equipment. 3. A process of gripping a bonding wire having both ends fixed by a joint with a grip jig, a process of cutting the bonding wire gripped by the grip jig with a cutter, and a step of cutting the cut bonding wire. While gripping with the grip jig, a process of moving the grip jig in a direction substantially opposite to the bonding portion to give a tensile force to the bonding wire, and the tensile force breaking the bonding wire or peeling the bonding portion. And a step of measuring the tensile strength of the bonding wire or the peel strength of the bonding portion with a tensile tester connected to the grip jig. 4. The cutting piece of the bonding wire connected to one of the joints is gripped by the grip jig, and the tensile strength of the bonding wire or the peel strength of one of the joints is measured by the tensile tester. After measuring
A step of gripping a cutting piece of the bonding wire connected to the other of the bonding portions with the grip jig, and measuring the tensile strength of the bonding wire or the peel strength of the other bonding portion by the tensile tester. The bonding strength test method for the bonding wire according to claim 3. 5. The first and second bonding wires are provided.
Gripping with the grip jig, cutting the bonding wire between the first and second grip jigs with the cutter, gripping the cut pieces of the cut bonding wire, And a step of moving the second grip jig at the same time or separately to give a tensile force to the bonding wire, and when the bonding wire is broken or the joint portion is peeled off by the tensile force, the first and second The bonding strength test method for a bonding wire according to claim 3, further comprising a step of measuring a tensile strength of the bonding wire or a peel strength of the bonding portion by a tensile tester connected to the grip jig.