JPH08316260A - Wire bonding method and semiconductor manufacturing apparatus - Google Patents

Abstract

PURPOSE: To obtain a wire bonding method in which an ultralow loop in an arch height of about 100μm can be realized without damaging the neck part of a wire loop by a method wherein the operation of a bonding tool is controlled in a specific sequence. CONSTITUTION: The operation of a bonding head and that of a table on which the bonding head is mounted are controlled, a connecting electrode on a semiconductor chip 10 and a terminal 15 for external derivation on a package are connected by a bonding wire 13 which is pulled out from a bonding tool 5. In this case, one end of the bonding wire 13 is connected to the connecting electrode on the semiconductor chip 10, and the operation of the bonding tool 5 is controlled in the sequence of a first rise (1), a first fall and a parallel movement (2), a second rise (3) and a second fall and a parallel movement (4). Then, the other end of the bonding wire 13 is connected to the terminal 15 for external derivation on the package. For example, an operating track in a first fall and a parallel movement (2) and a second fall and a parallel movement (4) is set to be an arc shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire bonding technique, and for example, in an operation locus of a bonding tool in a wire bonder for bonding a gold wire or the like, an arch height can be increased without damaging a neck portion of a wire loop. The present invention relates to a wire bonding method capable of realizing an ultra-low loop of about 100 μm and a technique effectively applied to a semiconductor manufacturing apparatus.

[0002]

2. Description of the Related Art For example, in a wire bonder for gold wire bonding, the bonding tool itself can be moved in the Z-axis direction as a technology studied by the inventor, which is not publicly known. The XY table on which is mounted is movable in the X-axis and Y-axis directions, and the connection electrodes on the semiconductor chip and the external lead-out terminals of the package are connected by bonding wires by the operation control of the bonding tool and the XY table. It

By the way, in recent packages such as VLSI logic devices, the number of pins has been increased and the thickness has been reduced. For example, in order to realize a thin plastic package, the development of a technique / apparatus for forming a low loop and the wire material. Development is being demanded.

Therefore, in order to realize the low loop of the bonding wire, the development of the wire material has been mainly made at present. In the nail head bonding, the wire is directly under the ball due to the thermal effect of the discharge current when the wire is melted to form the ball. Since the neck recrystallizes and the arch height is determined by the length of the neck, the wire is being developed to control the discharge current and at the same time add an additive element that is difficult to recrystallize to shorten the neck. There is.

As for the wire bonding process, a loop forming technique for stabilizing the arch height has been developed. For example, in order to reduce the arch height, the clamper is controlled to pull out the bonding wire from the capillary. It is considered that the bonding is realized by reducing the loop to some extent by reducing the amount.

A technique relating to such wire bonding is described in documents such as "Practical course VLSI packaging technique (bottom)" P22 to P30 issued by Nikkei BP on May 31, 1993. .

[0007]

However, in the above-mentioned discharge current control, wire development, and clamper control techniques, bonding can be achieved by lowering the loop to some extent, but the neck portion of the loop is damaged. Since this damage cannot be reduced, the tensile strength of the wire cannot be obtained, which causes a disconnection during molding after wire bonding.

Therefore, an object of the present invention is to control the operation locus of the bonding tool to realize an ultra-low loop with an arch height of about 100 μm without damaging the neck portion of the wire loop. It is to provide a wire bonding method and a semiconductor manufacturing apparatus.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0010]

Of the inventions disclosed in the present application, a representative one will be briefly described below.
It is as follows.

That is, according to the wire bonding method of the present invention, by controlling the operation of the bonding head and the table on which the bonding head is mounted, the connection electrode on the semiconductor chip and the external lead terminal of the package are pulled out from the bonding tool. The present invention is applied to the case where the bonding wire is connected by the bonding wire, and the operation of the bonding tool after connecting one of the bonding wires to the connection electrode on the semiconductor chip is performed by the first rising, the first descending and parallel movement, The other of the bonding wires is connected to the external lead-out terminal of the package by controlling the second ascending, the second descending, and the parallel movement in this order.

[0012] Specifically, the operation control of the bonding tool is operated up to several times as high as the arch height of the wire loop required for the first ascent, and then the wire loop is moved for the first descending and parallel movement. To the position of the external lead-out terminal of the package by the second descending and parallel movement. The arch height of the wire loop is about 100 μm,
Further, the operation loci in the first descending and parallel moving and the second descending and parallel moving are arcuate.

Further, in the semiconductor manufacturing apparatus of the present invention, at least the bonding wire is positioned at the position of the connection electrode on the semiconductor chip and one of the bonding wires is connected to the connection electrode on the semiconductor chip in order to control the operation trajectory of the bonding tool. Connect, then raise to a height several times higher than the required wire loop arch height, then descend and translate to near the wire loop arch height, then raise the wire loop length and then descend. Further, there is provided means for parallelly moving and positioning at the position of the external lead-out terminal of the package to connect the other bonding wire to the external lead-out terminal of the package.

[0014]

According to the wire bonding method and the semiconductor manufacturing apparatus described above, the operation of the bonding tool in the wire bonding between the connection electrode on the semiconductor chip and the external lead-out terminal of the package is the first ascending, descending and parallel operation. By performing the movement, the second ascent and descent and the parallel movement, the arch height of the wire loop is determined by the locus of the first ascending and descending and the parallel movement, and the second ascending and descending the second time. And the length of the wire loop can be determined by the translation.

For example, when the arch height of the wire loop is to be suppressed to about 100 μm, the wire is operated by operating the bonding tool up to a height several hundred times the arch height of 100 μm, for example, 300 to 500 μm. A low loop can be achieved.

Further, since the arch height of the wire loop, that is, the length of the neck portion corresponding to this arch height is determined by the trajectory of the first ascent and descent and the parallel movement of the first time, the loop is made low. It is possible to suppress the friction between the bonding tool and the wire, as compared with the conventional reverse mode operation that enables the above, and thereby reduce the damage given to the neck portion of the wire.

Further, the shape of the wire loop and the arch height and the like differ depending on the motion locus in the first first downward movement and parallel movement and the second second downward movement and parallel movement. When the locus is arcuate, the shape of the wire loop becomes gentler and the arch height can be made lower than that of a straight line.

As a result, the arch height is about 10 without damaging the neck portion of the wire loop.
Since the ultra-low loop of 0 μm can be achieved, it is possible to realize both reduction of damage at the neck portion of the wire loop and ultra-low loop of the wire loop.

[0019]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is an external perspective view showing an example of a wire bonder which is an embodiment of the present invention, FIG. 2 is an explanatory view showing the state of each wire bonding process in the wire bonder of this embodiment, and FIG. 3 is a bonding tool. 4 is an explanatory view showing an example of the operation locus of the bonding tool and the wire loop state of the wire, FIG. 4 is an explanatory view showing an example of the operation path of the bonding tool in the prior art compared with this embodiment, and FIG. Cross-sectional view showing the main part relation of,
FIG. 6 is an explanatory diagram showing another example of the conventional technique.

First, the structure of the wire bonder of this embodiment will be described with reference to FIG.

The wire bonder of this embodiment is a wire bonder for nail head bonding by a thermocompression bonding method using, for example, a gold (Au) wire. A feeder section 2 for carrying and carrying out wire bonding by stopping at a predetermined position, an unloader section 3 for housing the wire-bonded substrate, and an X-axis, Y-axis, and Z-axis direction for driving on the chip. It comprises a bonding head portion 4 for wire bonding between the connection electrode and the external lead-out terminal on the substrate.

The bonding head unit 4 detects a capillary 5 (bonding tool) through which a gold wire is passed, a tool holder 6 to which the capillary 5 is attached, an XY table 7 that moves in the X-axis and Y-axis directions, and the positions of the chip and the substrate. A tool holder 6 including a camera 8 and having a capillary 5 attached at its tip is moved up and down, and a gold wire is connected between the bonds by controlling the operation with an XY table 7 on which the bonding head 4 is mounted. A loop is formed, and at this time, the relative position between the substrate and the chip die-bonded thereon is detected by the camera 8 mounted on the bonding head unit 4 so that the gold wire is connected to a predetermined position. Has become.

Further, in order to control the movement locus of the capillary 5 by the relative movement control of the tool holder 6 to which the capillary 5 is attached to the bonding head portion 4 and the XY table 7 on which this bonding head portion 4 is mounted. Is connected to the controller 9 (head control means) to control a series of wire bonding operations, and in particular, after one of the gold wires is connected to the connection electrode on the semiconductor chip, the operation of the capillary 5 is Controlled in the order of 1 rise, 1st fall and parallel movement, 2nd rise, 2nd fall and parallel movement, the other of the gold wires is connected to the external lead-out terminal of the package. .

Next, regarding the operation of this embodiment, the basic operation of wire bonding will be described with reference to FIG.

First, the chip 1 supplied from the loader unit 1
The substrate 11 on which 0 is die-bonded is conveyed by the feeder unit 2, stopped at a predetermined position on the feeder unit 2 and positioned at the wire bonding position. At the same time, the capillaries 5 of the bonding head unit 4 are also positioned at the positions of the predetermined connection electrodes on the chip 10.

Then, the gold wire 13 is formed from the wire spool 12.
(Bonding wire) is supplied, and the tip of the gold wire 13 passed through the capillary 5 is melted by a ball forming torch 14 such as an electric torch or a gas flame to form a ball (FIG. 2).
(a)). Further, the capillaries 5 press-bond the balls onto the connection electrodes on the chip 10 die-bonded onto the substrate 11 (FIG. 2 (b)).

After that, the gold wire 13 is guided to the inner lead 15 of the external lead-out terminal on the substrate 11, and the capillary 5 is inserted.
The gold wire 13 is crimped onto the inner lead 15 at the edge of (Fig. 2 (c)). Then, the gold wire 13 is sandwiched by the clamper 16 and pulled to cut the gold wire 13 (FIG. 2 (d)).

As a result, the bonding of one wire is completed, and thereafter, the above basic operation is repeated for all the connection electrodes on the chip 10 and the inner leads 15 of the external lead-out terminals, so that one substrate 11 is formed. Wire bonding is completed.

Then, the substrate 11 on which wire bonding has been completed is conveyed by the feeder unit 2, and this wire-bonded substrate 11 is stored in the unloader unit 3. All the substrates 11 stored in the loader unit 1 are subjected to the above operation.
Repeat for.

Next, regarding the operation control of the capillary 5 during wire bonding, which is a feature of this embodiment,
After connecting one of the gold wires 13 to the connection electrode on the chip 10, the procedure until the other of the gold wires 13 is connected to the inner lead 15 of the external lead-out terminal under the control of a predetermined locus is shown in FIG. explain.

In FIG. 3, the broken line portion shows the loop shape of the gold wire 13 after the wire bonding is completed, and the solid line portion shows the movement locus of the tip of the capillary 5. Has become.

First, after connecting one of the gold wires 13 to the connection electrode on the chip 10, the gold wire 13 is operated up to several times as high as the arch height of the wire loop required by the first rise (). After that, it is moved to the arch height of the wire loop by, for example, an arc-shaped trajectory by the first descending and parallel movement ().

Further, the wire loop is operated by the length of the wire loop required for the second ascent (). After that, the second descending and parallel movement is performed to the position of the inner lead 15 of the external lead-out terminal, for example, in an arcuate locus ().

Then, a positioning operation is performed to connect the inner lead 15 to a predetermined position (-). Thereby, the other of the gold wires 13 can be connected to the inner lead 15 of the external lead-out terminal.

In this series of movements of the capillary 5, the arch height of the wire loop is substantially determined by the first ascent and then the first ascent and translation, for example in this case the first ascent. 300-50
After operating up to a height of 0 μm, it moves in an arcuate trajectory by the first descending and parallel movement, so the arch height is about 1
It can be set to 00 μm. It should be noted that this movement locus can also be moved along the lines'- 'indicated by the one-dot chain line.

Therefore, according to the wire bonder of this embodiment, one of the gold wires 13 is connected to the connection electrode on the chip 10 and the other of the gold wires 13 is connected to the inner lead 15 of the external lead-out terminal. By controlling the operation locus of the capillary 5, the arch height of the wire loop can be made extremely low to about 100 μm, and damage to the neck portion of the wire loop can be reduced.

For example, in the prior art compared with this embodiment, in the case of the reverse mode operation which enables the low loop as shown in FIG. 4, when the gold wire 13 is taken out from the capillary 5 by the reverse operation. As shown in Fig. 5, it rubs against the inside of the capillary 5 and damage remains on the neck,
Further, in the case of the normal mode operation as shown in FIG. 6, the gold wire 13 is not rubbed and only bending force is applied to the gold wire 13 to cause less damage, but the loop cannot be made low, and a compatible technique as in the present embodiment is desired. It is rare.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the embodiments and various modifications can be made without departing from the scope of the invention. Needless to say.

For example, the wire bonder of this embodiment has been described as a wire bonder for nail head bonding by thermocompression bonding using a gold wire.
The present invention is not limited to the above-described embodiment, but can be widely applied to nail head bonding by the ultrasonic combined thermocompression bonding method and wire bonder by the wedge bonding by the ultrasonic method.

In the wedge bonding by the ultrasonic method, a wire is crimped by a bonding tool called a wedge while applying ultrasonic waves to a connecting electrode on a chip and a terminal for external extraction, and can be bonded at room temperature. The feature is that it is suitable for fine pitch of electrodes as compared with nail head bonding.

In the wedge bonding, since an aluminum wire is used as a wire, the aluminum wire has low strength and is easily corroded. Therefore, the aluminum wire can be mainly used for a hermetically sealed ceramic package.

[0043]

Advantageous effects obtained by typical ones of the inventions disclosed in the present application will be briefly described.
It is as follows.

(1). After connecting one of the bonding wires to the connection electrode on the semiconductor chip, the operation of the bonding tool is changed to the first rising, the first lowering and parallel movement, the second rising, and the second rising. By controlling the descending and parallel movements in order and connecting the other side of the bonding wire to the external lead-out terminal of the package, the arch height of the wire loop can be determined by the first ascending and descending and parallel movements. The first rise raises the arch height of the wire loop to approximately 100 by operating to several times the arch height.
It becomes possible to make an ultra low loop to μm.

(2) According to the above (1), the length of the neck portion corresponding to the arch height of the wire loop can be determined by the trajectory of the first ascent and descent and the parallel movement of the first time. It is possible to suppress rubbing between the tool and the wire and reduce damage to the neck portion of the wire loop.

(3) In the above (1), when the operation locus of the bonding tool in the first descending and parallel movement and the second descending and parallel movement is arcuate, the shape of the wire loop is determined by this operation locus. Further, since the arch height and the like can be changed in accordance with this shape, it becomes possible to make the shape of the wire loop gentle by making the motion locus arc-shaped and further achieve an ultra-low loop of the arch height. .

(4) By the above (1) to (3), it is possible to control the movement locus of the bonding tool in the wire bonder to reduce the damage in the neck portion of the wire loop and to realize the ultra-low loop of the wire loop. Can be realized.

[Brief description of drawings]

FIG. 1 is an external perspective view showing an example of a wire bonder that is an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a state in each processing procedure of wire bonding in the wire bonder of the present embodiment.

FIG. 3 is an explanatory diagram showing an example of an operation locus of a bonding tool and a loop state of a wire in the present embodiment.

FIG. 4 is an explanatory diagram showing an example of an operation trajectory of a bonding tool in a conventional technique compared with this embodiment.

5 is a sectional view showing a main part relationship between a bonding tool and a wire in FIG.

FIG. 6 is an explanatory diagram showing another example of the operation locus of the bonding tool in the related art compared with the present embodiment.

[Explanation of symbols]

 1 Loader Section 2 Feeder Section 3 Unloader Section 4 Bonding Head Section 5 Capillary (Bonding Tool) 6 Tool Holder 7 XY Table 8 Camera 9 Control Section (Head Control Means) 10 Chip 11 Board 12 Wire Spool 13 Gold Wire (Bonding Wire) 14 Ball forming torch 15 Inner lead 16 Clamper

Continued Front Page (72) Inventor Yasushi Ishii 3-3 Fujibashi, Ome City, Tokyo 2 Inside Hitachi Tokyo Electronics Co., Ltd.

Claims (5)

[Claims] 1. A wire bonding for connecting a connection electrode on a semiconductor chip and an external lead-out terminal of a package with a bonding wire pulled out from a bonding tool by controlling operation of a bonding head and a table on which the bonding head is mounted. A method of connecting one of the bonding wires to a connection electrode on the semiconductor chip, and then performing operations of the bonding tool including a first raising, a first lowering and a parallel movement;
And the second lowering and parallel movement are controlled in this order to connect the other of the bonding wires to the external lead-out terminal of the package. 2. The wire bonding method according to claim 1, wherein the operating means of the bonding tool is:
After operating to a height several times as high as the arch height of the wire loop required for the first ascent, the first descending and parallel movement is made to operate near the arch height of the wire loop, and further to the second The wire bonding method is characterized in that the wire loop is operated for the length of the wire loop by the ascent of the wire and then moved to the position of the external lead-out terminal of the package by the second descending and parallel movement. 3. The wire bonding method according to claim 1, wherein the arch height of the wire loop is about 100 μm by controlling the operation (trajectory) of the bonding tool by the wire bonding method.
And a wire bonding method. 4. The wire bonding method according to claim 1, 2 or 3, wherein the operation loci in the first descending and parallel movement and in the second descending and parallel movement are arcuate. Wire bonding method. 5. A semiconductor manufacturing method in which a bonding head and a table on which the bonding head is mounted are controlled in operation to connect a connection electrode on a semiconductor chip and an external lead terminal of a package with a bonding wire drawn from a bonding tool. An apparatus, at least, positioning the bonding tool at a position of a connection electrode on the semiconductor chip to connect one of the bonding wires to a connection electrode on the semiconductor chip, and then an arch of a wire loop required. The height of the wire loop is raised several times, and then the wire loop is lowered and translated to the vicinity of the arch height, and the wire loop is raised by the length of the wire loop and then lowered and translated to the outside of the package. Position it at the position of the lead-out terminal and A semiconductor manufacturing apparatus comprising means for connecting the other of the wire to the external lead-out terminal of the package.