JPH0669258A - Silver paste supply unit - Google Patents

Abstract

PURPOSE:To supply stable silver paste without consuming wasteful man-hours irrespective of a size of a semiconductor element to be placed on an island of a semiconductor lead frame. CONSTITUTION:The silver paste supply unit comprises a screen 13 having a plurality of meshlike holes 12 of a small rectangular shape having different sizes, and rotatable screen drivers 14, 14' at both ends of the screen 13. A squeegee 10 is fixed to an end of a syringe 1 to be vertically and laterally moved simultaneously with the syringe 1. Thus, a hole having a small diameter of a size matching the size of a semiconductor element to be placed can be simply selected. Since the paste supplied to the hole 12 of the small rectangular shape is supplied to an island of a semiconductor lead frame 8 through the mesh, the paste can be stably supplied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silver paste supply unit in a semiconductor device manufacturing apparatus, and more particularly to a silver paste supply unit in a semiconductor element die bonding apparatus.

[0002]

2. Description of the Related Art A conventional silver paste supply unit has a hollow cylindrical syringe 1 and a silver paste supply nozzle 2 having a small diameter hole fixed to the lower end of the syringe 1 as shown in FIG.
And an air supply tube 3 that feeds air into the silage 1.
And a dispensing device 4 that controls the pressure and pressurization time of air sent into the syringe 1, a syringe holding block 5 that holds the syringe 1 fixedly, and can move up and down, and a syringe that moves the syringe holding block 5 up and down. The vertical drive device 6 is provided, and after the syringe vertical drive device 6 lowers the syringe 1 onto the island 9 of the semiconductor lead frame 8 supplied on the guide rail 7, the silver paste supply nozzle 2 is supplied by the dispensing device 4. A certain amount of silver paste was supplied from the tip of the.

[0003]

In this conventional silver paste supply unit, since the small diameter hole of the silver paste supply nozzle 2 fixed to the tip of the syringe 1 is only one place, only a very small amount of silver paste can be supplied and it can be mounted. The size of the semiconductor element (semiconductor pellet) has been limited to a small one having a square shape with a side of 1 to 2 mm.

Therefore, in order to supply the amount of silver paste required for mounting a large-sized semiconductor element, the hole diameter of the silver paste supply nozzle 2 is increased or the setting of the dispensing device 4 is changed to adjust the pressure of the supplied air. Although the pressure was increased and the pressurization time was lengthened, the supplied silver paste concentrates at one point and rises, or the silver paste drips from the tip of the silver paste supply nozzle 2 to cause die bonding failure. There was a problem.

For this reason, as shown in FIGS. 5 (a) and 5 (b), a plurality of small diameter holes 17 at the tip of the silver paste supply nozzle 2 are provided depending on the size of the semiconductor element to be mounted. Each time the size is changed, the syringe 1 has to be removed from the syringe holding block 5 and only the silver paste supply nozzle 2 at the tip has to be replaced, resulting in a waste of man-hours for the replacement work.

[0006]

The silver paste supply unit of the present invention comprises a squeegee having a lower surface opening fixed to the tip of a syringe, and a screen having a plurality of small holes on a mesh below the squeegee at different intervals. A screen feed drive device that fixes both ends of the screen and is rotatable, and two syringe drive devices that operate the syringe holding block vertically and horizontally.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the invention will be described with reference to the drawings.

FIG. 1 is a perspective view of a silver paste supply unit according to a first embodiment of the present invention. Hollow cylindrical syringe 1
A silver paste supply nozzle 2 having a small diameter hole at the lower end of
A squeegee 10, which is an L-shaped block having an opening on the lower surface, is fixed. The syringe 1 is a syringe drive device 6,1.
A cap that is fixed to a syringe holding block 5 that can move up and down and left and right by 1 and that connects an air supply tube 3 that feeds air into the syringe 1 at the upper end of the syringe 1 while keeping the inside of the syringe 1 in a sealed state. Is provided, and at the tip of the air supply tube 3, a dispensing device 4 that controls the pressure and pressurization time of the air sent into the syringe 1 is installed. Below the squeegee 10, a screen 13 having a plurality of mesh-shaped small holes of different sizes, preferably small rectangular holes 12, provided at regular intervals is fixed to two left and right screen feed drive devices 14, 14 '.

Next, the operation of the silver paste supply unit according to the first embodiment of the present invention will be described with reference to the drawings.

First, in FIG. 2A, the screen feed driving devices 14 and 14 'are rotated to match the size of the semiconductor element (semiconductor pellet) mounted on the island 9 of the semiconductor lead frame 8 supplied below the screen 13. The screen 13 is operated so that the small rectangular hole 12 located directly below the silver paste supply nozzle 2. Next, the vertical drive device 6 of the syringe 1 causes the gap between the back surface of the screen 13 and the front surface of the semiconductor lead frame 8 to be several tens of μm.
After descending to a height of ˜0.1 mm, the dispensing device 4 is operated to supply a fixed amount of the silver spacer 15 onto the screen 13 (FIG. 2 (b)). At this time, the screen 13 is pushed downward by the squeegee 10 and is under tension. In this state, the left and right driving device 11 of the syringe 1 operates the syringe 1 to a position where the tip of the squeegee 10 passes through the small rectangular hole 12 (see FIG. 2).
(C)). Next, the syringe 1 is raised by the vertical drive device 6, and at the same time, the semiconductor lead frame 8 is fed by one pitch (FIG. 2D), and the syringe 1 is returned to the position of FIG. 2A by the horizontal drive device 11. The above operation is repeated and the silver paste is supplied onto all the islands 9 of the semiconductor lead frame 8.

Next, FIG. 3 shows a second embodiment of the present invention. In the first embodiment, cotton cloth or the like is fixed to the outer circumference of each pair of screen driving devices 14 and 14 'and the squeegee 10. The cleaning roller 16 is provided. Other configurations and operations are the same as those in the first embodiment.

Since the cleaning roller 16 can wipe off the silver paste remaining on the front and back surfaces of the screen 13, the silver paste can be supplied more stably and the cleaning frequency of the screen 13 can be reduced. Have.

[0013]

As described above, according to the present invention, a plurality of small holes having different sizes are provided on the screen below the syringe,
Preferably, the small rectangular holes and the driving device capable of sending the screen to the left and right with a constant pitch are provided, so that the silver paste suitable for the size of the semiconductor element mounted on the semiconductor lead frame can be supplied with one touch.

Further, since each of the small rectangular holes has a mesh shape, there is an effect that the silver paste can be uniformly and stably supplied without dropping of the silver paste.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of the present invention.

FIG. 2 is a diagram showing an operation of the first exemplary embodiment of the present invention.

FIG. 3 is a front view showing a second embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a conventional silver paste supply unit.

FIG. 5 is a cross-sectional view showing a conventional silver paste supply nozzle.

[Explanation of symbols]

 1 Syringe 2 Silver Paste Supply Nozzle 3 Air Supply Tube 4 Dispensing Device 6 Syringe Vertical Drive 8 Semiconductor Lead Frame 9 Island 10 Squeegee 11 Syringe Horizontal Drive 12 Small Rectangular Hole 13 Screen 14 Screen Feed Drive 15 Silver Paste 16 Cleaning Roller 17 Small diameter hole for supply nozzle

Claims (1)

[Claims] 1. A hollow cylindrical silver paste storage component (hereinafter referred to as a syringe), a silver paste supply nozzle having a small diameter hole fixed to the lower end of the syringe, and an air supply tube for feeding air into the syringe. It has a dispensing device that controls the pressure of the air to be sent and the pressurization time,
In a silver paste supply unit that supplies a certain amount of silver paste to a semiconductor element mounting portion (hereinafter referred to as an island) of a semiconductor lead frame, an L-shaped block (hereinafter referred to as a squeegee) having a bottom opening fixed to the tip of the syringe.
A screen having a plurality of mesh-shaped small holes each having a different size under the squeegee at regular intervals, a screen feed drive device capable of fixing both ends of the screen and rotating, and holding and holding the syringe, A silver paste supply unit comprising: a syringe holding block that can be moved left and right; and a syringe drive device that moves the syringe holding block vertically and horizontally.