JPH09115928A - Diebonding method and its device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a diebonding method and its device which can suppress liquid leak of epoxy resin occurring at nozzle terminal being attached to a syringe. SOLUTION: A needle bulb 10 contacts to inner wall 3d of a nozzle 3 with tapered shape and closes route 3 during waiting time for an applying work of epoxy resin 2, therefore the epoxy resin 2 is prevented from leaking from a nozzle terminal 3a. After a syringe 1 is transferred to a predetermined position by an arm 4 and it descends, terminal of a needle 12 contacts to a lead frame 13, and the needle bulb 10 opens when the syring 1 descends until it contacts to the nozzle terminal 3a. The epoxy resin 2 is ejected to the lead frame 13 from the nozzle by providing air with a higher pressure than an atmospheric pressure into the syringe 1 under condition. When the ejection of the epoxy resin 2 finishes, air supplying stops and the syringe 1 is elevated by the arm 4 above the lead frame 13, therefore liquid leak does not occur because the needle bulb 10 closes again.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die bonding apparatus for applying a required amount of epoxy resin to a predetermined portion to fix a semiconductor chip.

[0002]

2. Description of the Related Art Conventionally, in a manufacturing process in which a semiconductor chip is arranged in a package and connected to a lead frame, a die bonding apparatus for bonding and fixing the semiconductor chip to the lead frame with an epoxy resin is used.

A die bonding apparatus is an apparatus for applying a fixed amount of epoxy resin to a predetermined position (position where a bonding pad is provided) on a lead frame and fixing a semiconductor chip to the position where the epoxy resin is applied. Is.

In the process of manufacturing this semiconductor chip,
The accuracy of the amount of epoxy resin applied is important. In particular, for a minute semiconductor chip having a size of about 300 μm square, it is necessary to apply about 0.01 μL (microliter) of epoxy resin and apply a hemispherical shape with a diameter of about 500 μm.

This epoxy resin is applied by a method called a dispensing method. In this dispensing method, a liquid epoxy resin 2 is stored in a syringe 1,
This is a method in which a certain amount of epoxy resin 2 is extruded from a nozzle 3 provided on a syringe tip end 1a using air pressure and applied onto a lead frame.

The epoxy resin 2 is applied to the syringe 1
Is moved to a predetermined position by the driving means 4 and then lowered. When the tip 3a of the nozzle 3 comes into contact with the surface of the lead frame, the lowering is stopped, and the syringe rear end (upper end) 1b.
The compressed air is supplied by the tube 6 connected to the via the flange 5, and the epoxy resin 2 is extruded and applied.

[0007]

By the way, in the prior art, the syringe 1 and the nozzle 3 stand by above the lead frame until the next application except at the moment of applying the epoxy resin 2 to the lead frame. Becomes During this time, the pressure in the syringe 1 is kept at a pressure that equilibrates with the atmospheric pressure.

However, even when the pressure inside the syringe 1 is kept in equilibrium, the epoxy resin 2 naturally drops from the nozzle tip 3a due to its own weight and vibration. This is referred to as liquid sag 7, and the liquid sag 7 is attached to and accumulated in the nozzle tip due to surface tension (see FIG. 3). The epoxy resin 2 described above when the epoxy resin 2 is accumulated at the nozzle tip 3a
It becomes difficult to control the coating amount of the chip, and when die-bonding a small chip to a lead frame, the entire chip is covered with epoxy resin, or the tip of a collet (not shown) for adsorbing the chip and moving it, etc. It will adhere to and become dirty.

Therefore, in order to prevent the liquid dripping, the pressure in the syringe 1 is reduced to a pressure lower than the atmospheric pressure during the time other than the epoxy resin application work so that the excess epoxy resin 2
However, air bubbles are generated because air is taken in from the tip 3a of the nozzle while waiting for the application work of the epoxy resin 2, and the amount of application can be precisely controlled. No (see Figure 4).

The inventors of the present invention have obtained a 360 μm square and a thickness of 160.
Die bonding 1000 μm semiconductor chips,
The number of surface contaminations of the semiconductor chip due to the epoxy resin and the defective shear strength of the semiconductor chip were measured. as a result,
The contamination of the surface of the semiconductor chip was 64, and the shear strength defect was 24.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above problems and provide a die bonding method and an apparatus therefor capable of suppressing liquid sagging of an epoxy resin generated at the tip of a nozzle attached to a syringe. is there.

[0012]

In order to achieve the above object, the present invention provides a method of die bonding using a syringe containing a bonding resin, in which a needle valve protruding from and retracting to a nozzle at the tip of the syringe is housed. The needle valve is opened when the nozzle at the tip comes into contact with the lead frame.

Further, according to the present invention, in a device for die-bonding using a syringe containing a bonding resin, a needle valve is provided at a nozzle at the tip of the syringe so as to be openable and closable.

In addition to the above construction, in the present invention, a spring for biasing the needle valve to the closed state may be provided between the needle valve and the syringe.

With the above structure, while the bonding resin applying operation is on standby, the needle valve comes into contact with the tapered inner wall of the nozzle to close the resin path, so that the bonding resin drops (drips) from the nozzle tip. Never. When the syringe moves to a predetermined position and then descends, the needle tip of the needle valve comes into contact with the lead frame and the needle valve opens. By supplying air having a pressure higher than the atmospheric pressure into the syringe in this state, the bonding resin is discharged from the nozzle to the lead frame. When the discharging of the bonding resin is completed, the supply of air is stopped, the syringe is separated from the lead frame, and the needle valve is closed, so that the liquid does not drip.

When a spring for biasing the needle valve to the closed state is provided between the needle valve and the syringe, the needle valve is pressed against the inner wall of the nozzle, so that the liquid dripping is suppressed more reliably. It can be used even if the bonding speed becomes faster.

[0017]

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

FIGS. 1A and 1B are conceptual views showing an embodiment of an apparatus to which the die bonding method of the present invention is applied. The same reference numerals are used for the same members as in the conventional example shown in FIGS. 3 and 4.

As shown in FIG. 1A, a discharge hole (for example, an inner diameter of about φ) of an epoxy resin 2 as a bonding resin is formed.
A top-shaped valve (hereinafter referred to as "needle valve") with a needle on a dispensing nozzle 3 having a diameter of 0.2 mm).
10 are provided. The lower portion of the valve body 11 of the needle valve 10 is formed in a taper shape of approximately 45 degrees, and the needle 12 is connected to the tip (lower end) thereof. The length of the needle 12 is longer than the length of the path 3c for discharging the epoxy resin 2 of the nozzle 3. The rear end (upper end) 3 of this nozzle 3
At point b, the tip 1a of a substantially cylindrical syringe 1 containing an epoxy resin 2 of about 70 Pa · s is attached.
A flange 5 is attached to the rear end 1b of the syringe 1, and a tube 6 for supplying compressed air into the syringe 1 is connected thereto. The syringe 1 is provided with an arm 4 as a drive unit for moving the syringe 1 vertically and horizontally and holding it.

Next, the operation will be described.

While waiting for the application of the epoxy resin 2, the needle valve 10 contacts the tapered inner wall 3d of the nozzle 3 and closes the path 3c of the epoxy resin 2, so that the epoxy resin 2 drops from the nozzle tip 3a ( There is no dripping. When the syringe 1 is moved to a predetermined position by the arm 4 and then descends, the tip 12a of the needle 12 contacts the lead frame 13, and when the syringe 1 descends until it contacts the nozzle tip 3a, the needle valve 10 opens. In this state, by supplying air having a pressure higher than the atmospheric pressure from the tube 6 into the syringe 1, the epoxy resin 2 is discharged from the nozzle 3 to the lead frame 13. When the discharge of the epoxy resin 2 is completed, the supply of air is stopped, the syringe 1 is raised by the arm 4 above the lead frame 13, and the needle valve 10 is closed again. Therefore, the liquid does not drip while waiting for die bonding.

With such a die bonding apparatus,
No pressure is applied to the bonding pad of the copper lead frame.
Dispensing could be performed at 5 Kgf / cm ² and a pressing time of 30 msec.

Next, the basis for the optimum conditions will be described.

The outer diameter of the needle for opening and closing the valve in the nozzle attached to the syringe containing the epoxy resin is preferably 30% to 60% of the inner diameter of the epoxy resin discharge hole of the nozzle.

FIG. 2 is a conceptual diagram showing another embodiment of the die bonding method of the present invention.

The difference from the embodiment shown in FIGS. 1A and 1B is that a spring 14 for biasing the needle valve 10 to a closed state is provided between the needle valve 10 and the syringe 1. It is a point.

With this structure, the needle valve 10 can be smoothly opened and closed even when the epoxy resin 2 having a high viscosity of 130 Pa · s to 330 Pa · s is die-bonded or is die-bonded at a high speed. No dripping will occur.

As described above, according to the present embodiment, the application amount of the epoxy resin can be stably controlled only by controlling the air pressure in the syringe and the time for supplying the air pressure. Further, in the die bonding process of the semiconductor chip, it is possible to prevent liquid sagging of the epoxy resin, and to secure a stable supply of the epoxy resin coating amount.

According to the present embodiment, the thickness is 360 μm square and the thickness is 1
Die-bond a 60 μm semiconductor chip to 1
The frequency of occurrence of contamination and poor shear strength on the surface of 000 semiconductor chips was examined. As a result, 64 out of 1000 semiconductor chip surface stains became 2
The number of defective shear strength, which was 24 out of 0, was reduced to 3, respectively.

[0030]

In summary, according to the present invention, the following excellent effects are exhibited.

In the process of die-bonding a semiconductor chip using a liquid epoxy resin, when the needle valve contacts the inner wall of the nozzle and the needle exposed from the nozzle tip contacts the lead frame while the die bonding apparatus is on standby. Since the needle valve only separates from the inner wall of the nozzle, it is possible to prevent the epoxy resin from dripping at the tip of the nozzle.

[Brief description of the drawings]

1A and 1B are conceptual diagrams showing an embodiment of a die bonding method of the present invention.

FIG. 2 is a conceptual diagram showing another embodiment of the die bonding method of the present invention.

FIG. 3 is a conventional example of a die bonding method.

FIG. 4 is another conventional example of a die bonding method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Syringe 2 Bonding resin (epoxy resin) 3 Nozzle 3a Nozzle tip 3d Inner wall 4 Driving means (arm) 10 Needle valve 12 Needle 13 Lead frame

Claims (3)

[Claims] 1. A method of die-bonding using a syringe containing a bonding resin, wherein a needle valve protruding from and retracting to a nozzle at the tip of the syringe is accommodated, and the needle valve when the nozzle at the tip of the syringe abuts on a lead frame A die bonding method characterized in that the opening is made. 2. An apparatus for die bonding using a syringe containing a bonding resin, wherein a needle valve is provided at a nozzle at the tip of the syringe so as to be openable and closable. 3. The die bonding apparatus according to claim 2, wherein a spring for urging the needle valve in a closed state is provided between the needle valve and the syringe.