JP2000223524A - Wire bonder and wire-bonding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a wire bonder and a wire-bonding method whereby the chip height is detectable, without needing a separate exclusive appearance inspector. SOLUTION: In this wire bonding for connecting electrodes 3a of a chip 3 to electrodes 2a on a board 2 through bonding wires 4, a ball formed on the top end of the wire 4 is contacted and bonded to the electrode 3a, the height position of a capillary tool 13 is detected at a timing at which a touch sensor detects the contact and the detection result is stored in a detection result memory, the chip height is computed, based on the stored detection result, and the obtained chip height is compared with a predetermined allowance of the chip height to output the comparison result. Thus it is possible to inspect the chip height in the wire bonding, without needing a separate exclusive inspector.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a wire bonding apparatus and a wire bonding method for electrically connecting a semiconductor chip to a substrate.

[0002]

2. Description of the Related Art As a method for electrically connecting a semiconductor chip mounted on a substrate to a circuit on the substrate, a method using wire bonding is known. In this wire bonding, the end of the wire is pressed against the electrode formed on the chip and bonded, and then the wire is guided to the circuit electrode of the substrate to perform bonding, thereby connecting the electrode of the chip and the electrode of the substrate. Is made to conduct through.

[0003] By the way, semiconductor packages tend to be smaller and thinner, and in a wire bonding step, it is required to manage the wire height after bonding to be equal to or less than a predetermined height. If the wire height exceeds a predetermined height and becomes excessive, the resin may not be completely covered at the time of resin sealing after bonding, and the protection of the wire may be insufficient. Also, depending on the type of product, such as a thermal head substrate for a printer, the chip height after mounting may be required to be within a certain allowable range. As described above, since the height of the chip mounted on the substrate needs to be controlled within a predetermined range, conventionally, after the wire bonding, a chip height inspection is performed by a special appearance inspection device.

[0004]

However, in this conventional method, the height of the chip is detected optically by separately picking up an image of the chip on the substrate with a visual inspection device after wire bonding. 1 sec. For detecting the height of one tip. The above-described time is required, and there is a problem that one board requires a considerable inspection time.

Accordingly, an object of the present invention is to provide a wire bonding apparatus and a wire bonding method capable of detecting a chip height without requiring a special appearance inspection apparatus separately.

[0006]

According to a first aspect of the present invention, there is provided a wire bonding apparatus for connecting an electrode of a chip mounted on a substrate to an electrode of the substrate by a bonding wire. Height detection means for detecting the height, a detection result storage unit for storing a detection result by the height detection means, a chip height allowable value storage unit for storing a chip height allowable value, A tip height comparing means for comparing with a height allowable value.

According to a second aspect of the present invention, there is provided a wire bonding method for connecting an electrode of a chip mounted on a substrate and an electrode of the substrate by a bonding wire, wherein the bonding tool is connected to the electrode of the chip mounted on the substrate. Contacting a ball formed at the tip of a bonding wire held at the tip of the bonding wire to bond the ball to an electrode of a chip and detecting the height of the electrode by height detecting means; A step of storing the detected chip height in the detection result storage unit, a step of calculating the chip height based on the stored detection result, and a step of comparing the obtained chip height with a predetermined allowable value of the chip height. And outputting the comparison result.

According to the present invention, the tip height is calculated and obtained based on the height of the electrode detected when the ball held at the tip of the bonding tool is brought into contact with the tip electrode during wire bonding. Thus, the chip height can be inspected at the time of wire bonding without requiring a special inspection device separately.

[0009]

Embodiments of the present invention will now be described with reference to the drawings. 1 is a perspective view of a wire bonding apparatus according to an embodiment of the present invention, FIG. 2 is a perspective view of a substrate to be wire-bonded, FIG. 3 is a block diagram showing a configuration of a control system of the wire bonding apparatus, and FIG. FIG. 3 is a flowchart of the wire bonding method.

First, the structure of a wire bonding apparatus will be described with reference to FIG. A substrate 2 is mounted on the upper surface of the base 1, and elongated chips 3 are mounted in a row on the upper surface of the substrate 2. The chip 3 is electrically connected to the substrate 2 by bonding wires 4.

A movable table 10 is provided beside the base 1. The movable table 10 includes an X-axis motor 10X and a Y-axis motor 10Y. Movable table 10
A drive box 11 is provided on the upper side, and a horn 12 extends forward from the drive box 11. A capillary tool 13 is held at the tip of the horn 12, and a wire 15 fed from a spool 14 is inserted into the capillary tool 13. The wire 15 is clamped by a clamper 16 disposed above the capillary tool 13.

The torch 1 is located near the capillary tool 13.
7 are provided. By generating a spark between the distal end of the torch 17 and the wire 15 protruding from the distal end through the capillary tool 13, the distal end of the wire 15 is melted into a spherical shape to form a ball. When the X-axis motor 10X and the Y-axis motor 10Y are driven, the drive box 11 on the movable table 10 moves horizontally in the X and Y directions. Z not shown in the drive box 11
An axis motor is provided, and by driving the Z-axis motor, the capillary tool 13 moves up and down. The drive box 11 is provided with a camera 20.
Captures an image of the chip 3 on the substrate 2. Reference numeral 21 denotes a display monitor, which displays an imaging screen of the camera 20, a screen at the time of operation / input, and a predetermined notification.

Next, the substrate 2 and the chip 3 to be wire-bonded will be described with reference to FIG. In FIG. 2, an electrode 2a is formed on a substrate 2, and an electrode 3a is formed on a chip 3 mounted on the substrate 2. The electrode 2a and the electrode 3a are connected by a bonding wire 4. In this wire bonding, the ball formed at the distal end of the wire 15 is connected to the capillary tool 1 as described above.
3 by pressing against the electrode 3a.

In this bonding operation, the height position of the capillary tool 13 at the timing when the capillary tool 13 brings the ball into contact with the electrode 3a is detected by a touch sensor (not shown).
The starting point in the height direction of the loop of the bonding wire connecting a and the electrode 2a is obtained, and the height h of each electrode 3a can be obtained. Further, the substrate 2 and the chip 3
Are formed with recognition marks 2b and 3c for position recognition, respectively.

Next, the configuration of a control system of the wire bonding apparatus will be described with reference to FIG. In FIG. 3, a bonding operation control unit 30 controls the entire bonding operation by the wire bonding apparatus. The head driving unit drives an X-axis motor 10X for horizontally moving the drive box 11, a Y-axis motor 10Y, and a Z-axis motor 18 for vertically moving the capillary tool 13. Recognition section 33 is camera 20
The position of the chip 3 is recognized based on the data captured by the camera.

The ground height detector 34 is a height detector, and the lower end of the capillary tool 13 is connected to the electrode 3 of the chip 3.
The timing at which the capillary tool 13 a comes into contact is detected by the touch sensor 35, and the height position of the capillary tool 13 at that timing is obtained from the signal of the encoder of the Z-axis motor 18. That is, the height at each electrode 3a of the chip 3 (hereinafter, abbreviated as "chip height") is determined. The chip height obtained here is stored in the chip height detection result storage unit 37. The chip height comparison / determination unit 36 is a chip height comparison unit, and compares the chip height detection result with an allowable value stored in the chip height allowable value storage unit 38 to determine whether the chip height is acceptable. Do. The result of the pass / fail judgment is displayed on the display unit 32 and displayed on the screen of the monitor 21.

This wire bonding apparatus is configured as described above. The wire bonding method will be described below with reference to the flow chart of FIG. First, in FIG. 1, the substrate 2 on which the chip 3 is mounted is carried in, and is mounted on the base 1 (ST1). Next, an image of the substrate 2 is taken by the camera 20, whereby the recognition mark 2b of the substrate 2 is first recognized (ST2). Next, the recognition mark 3c of the chip 3 is similarly recognized (ST3). Then, wire bonding is performed between the electrode 3a of the chip 3 and the electrode 2a of the substrate 2 (ST
4).

At this time, the capillary tool 13 is
The height position of the upper surface of the electrode 3a is determined by the ground height detector 34 from the timing of contact with a, and is stored in the chip height detection result storage 37 (ST5). This process is sequentially performed on all the bonding targets. If there is no wire to be bonded in ST6, the chip height is calculated (ST7), and the obtained chip height is set to the chip height allowable. The value is compared with the allowable value stored in the value storage unit 38, and the comparison result is output (ST8).

As a result of the comparison, if the error exceeds the allowable value (ST9), error processing is performed (ST10), and the judgment result is displayed on the monitor 21. If the value is equal to or less than the allowable value in the determination of ST9 and the determination is a pass, the bonding of the next chip 3 is sequentially performed. That is, the steps after ST2 are repeated until it is confirmed in ST11 that there is no next chip. When it is confirmed that there is no next chip, the substrate 2 is unloaded (ST
12) End the wire bonding step.

As described above, the wire bonding method according to the present embodiment utilizes the detection result of the grounding height of the capillary tool, which has conventionally been used only for specifying the starting point in the height direction of the loop formation of the bonding wire. Then, the chip height is obtained. This eliminates the need for re-recognition by a visual inspection device separately for a product requiring chip height management after mounting, thereby simplifying the process and reducing equipment costs.

[0021]

According to the present invention, the tip height is calculated based on the electrode height detected when the ball held at the tip of the bonding tool is brought into contact with the tip electrode during wire bonding. Therefore, the chip height can be inspected at the same time in the wire bonding step without using a special appearance inspection apparatus, thereby simplifying the step and reducing the equipment cost.

[Brief description of the drawings]

FIG. 1 is a perspective view of a wire bonding apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view of a substrate to be wire-bonded according to an embodiment of the present invention.

FIG. 3 is a block diagram illustrating a configuration of a control system of the wire bonding apparatus according to the embodiment of the present invention;

FIG. 4 is a flowchart of a wire bonding method according to an embodiment of the present invention;

[Explanation of symbols]

 2 Substrate 3 Chip 4 Bonding wire 20 Camera 33 Recognition unit 34 Ground height detection unit 35 Touch sensor 36 Chip height comparison / determination unit 37 Chip height detection result storage unit 38 Chip height allowable value storage unit

Claims (2)

[Claims] 1. A wire bonding apparatus for connecting an electrode of a chip mounted on a substrate to an electrode of the substrate by a bonding wire, comprising: height detecting means for detecting the height of the electrode of the chip; A detection result storage unit that stores a detection result of the detection unit, a chip height allowable value storage unit that stores a chip height allowable value, and a chip height comparison unit that compares the detection result with a height allowable value. A wire bonding apparatus comprising: 2. A wire bonding method for connecting an electrode of a chip mounted on a substrate and an electrode of the substrate by a bonding wire, the tip of the bonding wire held by a bonding tool on the electrode of the chip mounted on the substrate. By contacting the ball formed in the part,
Bonding the ball to an electrode of the chip and detecting the height of the electrode by height detecting means; storing the detection result in a detection result storage unit; and detecting the chip height based on the stored detection result. A wire bonding method, comprising: calculating a height of the chip, comparing the obtained chip height with a predetermined allowable value of the chip height, and outputting a comparison result.