JP3697663B2 - Small workpiece mounting device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement of an apparatus for mounting a micro work on a mounting surface of an object to be mounted, and was developed mainly to detect an appropriate descending amount of a suction nozzle to a ball mounting position in a micro solder ball mounting apparatus. Is.
[0002]
[Prior art]
In the micro solder ball mounting apparatus, the wafer 1 that is a mounting object on which the solder ball is mounted must be formed flat without warping, and must be placed horizontally. As shown in FIG. 1, the wafer 1 is placed on an XY table 4 having an X-axis drive table 2 and a Y-axis drive table 3.
[0003]
However, the level of the XY table 4 may slightly change depending on the movement state, and the wafer 1 itself may not be horizontal due to manufacturing accuracy. Therefore, it is difficult to place the wafer 1 on the XY table while maintaining the level.
[0004]
However, if the flatness and levelness of the wafer 1 are not ensured, even if the suction nozzle 6 that sucks the solder balls 5 is lowered by a certain amount from the height that is the mechanical origin of the lifting device 9, strictly speaking, an XY table. Depending on the position in the wafer 1 placed on the wafer 4, the descent amount may be excessive or insufficient. This excess and deficiency of the descending amount has the following adverse effects when the solder ball 5 is very small (for example, a solder ball having a diameter of 0.1 mm).
[0005]
First, when the lowering amount is larger than necessary, such as the suction nozzle 6 on the right side of FIG. 3, the solder ball 5 bites into the nozzle hole of the suction nozzle 6 and is taken home without mounting the solder ball 5 on the wafer 1. Or the tip of the suction nozzle 6 comes into contact with the flux applied to the wafer 1 to cause the flux to adhere.
[0006]
Second, when the lowering amount is smaller than the required amount as in the suction nozzle 6 on the left side of FIG. 3, the solder ball 5 is dropped from the suction nozzle 6 to the wafer 1 and mounted. Then, depending on how the air is blown when the solder balls 5 are released, the solder balls 5 do not fall straight but roll and may not be mounted at a predetermined position.
[0007]
In some cases, the solder balls 5 sucked by the suction nozzle 6 do not come into contact with the flux applied to the wafer 1, so that the adhesive force of the flux does not act and the solder balls 5 are separated from the nozzle holes of the suction nozzle 6. Sometimes, the solder ball 5 was taken home.
[0008]
For this reason, it is considered to accurately measure the height of the mounting surface using a laser displacement meter or the like, but the laser displacement meter or the like is expensive and the attachment mechanism is complicated, and attachment errors are likely to occur. Therefore, the actual lowering amount of the suction nozzle 6 is not always reflected due to the mounting error.
[0009]
[Problems to be solved by the invention]
Accordingly, the present invention seeks to provide a micro work mounting apparatus that can obtain an appropriate lowering amount of the suction nozzle without using an expensive apparatus such as a laser displacement meter, and can securely mount the micro work on an object to be mounted. To do.
[0010]
[Means for Solving the Problems]
In order to solve the above problems, the present invention employs, as a first invention, the following means for a micro work mounting apparatus for mounting a micro work on a mounting surface of an object to be mounted.
First, a suction nozzle for sucking and holding a minute work is provided.
Secondly, a pressure detecting means for detecting a change in the internal pressure of the suction nozzle is provided.
Third, a moving means for moving the suction nozzle close to and separating from the mounting surface of the mounted object is provided.
Fourth, control means for controlling the moving means is provided.
Fifth, a change in the internal pressure of the suction nozzle is detected by bringing the suction nozzle closer to the mounting surface while applying a negative pressure or a positive pressure to the suction nozzle without holding the micro work.
Sixth, the amount of movement of the suction nozzle to a position where a predetermined pressure is set in advance is obtained. Seventh, the movement of the suction nozzle is controlled by the control means based on the amount of movement, and a minute work is mounted.
[0011]
Further, as the second invention, the following means are added to the first invention.
First, the movement amount is obtained at a plurality of locations on the mounting surface, and the inclination of the mounting surface is calculated.
Second, the movement of the suction nozzle is controlled by the control means based on the calculation result.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described together with examples according to the drawings. FIG. 1 is an explanatory perspective view showing an entire apparatus for mounting a fine solder ball according to an embodiment. In the embodiment, a solder ball 5 and a wafer 1 are selected as an object to be mounted according to the present invention. Of course, the micro work and the mounted object in the present invention are not limited to this.
[0013]
The fine solder ball mounting device is provided with a suction nozzle 6 that holds the solder ball 5 by vacuum suction, an XY table 4 on which the wafer 1 is placed, and a ball supply device 8 that feeds the solder ball 5 one by one. It has been. The XY table 4 is installed on the X-axis drive table 2 and the Y-axis drive table 3 and is configured to be movable on the plane.
[0014]
A vacuum source (not shown) and a pressure detection device 7 that detects a change in the internal pressure of the suction nozzle 6 are connected to the suction nozzle 6. In the figure, reference numeral 12 denotes an air tube for connecting the vacuum source and the suction nozzle 6. The vacuum source serves as a negative pressure source for sucking and holding the solder balls 5 and a negative pressure source for generating internal pressure in the suction nozzle 6 for pressure detection.
[0015]
As a moving device for the suction nozzle 6, there are an elevating device 9 and a horizontal moving device 10 that move the suction nozzle 6 close to and away from the mounting surface of the wafer 1, and the elevating device 9 and the horizontal moving device 10 are controlled by a control device 11. ing.
[0016]
In order to bring the suction nozzle 6 closer to the wafer 1 in the embodiment, an elevating device 9 is used. Therefore, the direction of approaching and separating from the wafer 1 is the vertical direction in the embodiment, but is not limited to this in the present invention. The horizontal moving device 10 is used for the suction nozzle 6 to go to the ball supply device 8 to pick up the solder balls 5, and is a moving device only in the Y-axis direction.
[0017]
Next, a method for detecting the amount of movement up to the ball mounting height in this embodiment will be described. When the solder ball 5 has a diameter of 0.1 mm and protrudes 0.07 mm from the tip of the suction nozzle 6 with the solder ball 5 being sucked by the suction nozzle 6, The appropriate height of the tip (appropriate mounting height) is 0.07 mm above the position of the electrode on the wafer 1. Therefore, the descending amount of the suction nozzle 6 from the mechanical origin of the lifting device 9 to the position is an appropriate moving amount. In order to detect this movement amount, attention is paid to the internal pressure of the suction nozzle 6.
[0018]
First, the suction nozzle 6 is brought close to the mounting position in the wafer 1 while applying a negative pressure from the vacuum source to the suction nozzle 6 without holding the solder ball 5. In the embodiment, the pressure in the suction nozzle 6 is −6.4 Kpa (unit kilopascals) when the suction nozzle 6 is sufficiently separated from the wafer 1 (a position not affected by the wafer 1). 6 changes in the internal pressure.
[0019]
The speed at which the suction nozzle 6 approaches the wafer 1 descends at a high speed from the top of the XY table 4 to a position of 2 mm (about 1.5 mm from the top of the wafer 1), and extremely low speed (0 .. 24 mm / sec) to start detection of the internal pressure in the suction nozzle 6.
[0020]
In the embodiment, when the internal pressure of the suction nozzle 6 from a height of 0.020 mm from the wafer 1 is displayed in a graph, it changes as shown in FIG. The internal pressure of the suction nozzle 6 at a height of 0.022 mm from the wafer 1 is -7.0 Kpa, the internal pressure of the suction nozzle 6 at a height of 0.018 mm from the wafer 1 is -8.0 Kpa, and the height from the wafer 1 is 0.0. The internal pressure of the suction nozzle 6 is −9.0 Kpa at 014 mm, the internal pressure of the suction nozzle 6 is 10.0 Kpa at a height of 0.005 mm from the wafer 1, and the internal pressure of the suction nozzle 6 is 11.0 Kpa at a position in contact with the wafer 1. It is.
[0021]
When the pressure reaches a predetermined pressure (in the embodiment, -0.8 Kpa is set as a threshold value) after the detection is started, the internal pressure of the suction nozzle 6 from the mechanical origin of the lifting device 9 of the suction nozzle 6 is -0. The amount of movement to the lowered position when 8 Kpa is detected is obtained. The amount of movement is such that the tip of the suction nozzle 6 is at a position 0.018 mm above the wafer 1. Based on this amount of movement, the position is 0.07 mm above the position of the electrode on the wafer 1 (appropriate mounting height). The required amount of movement is determined in advance.
[0022]
Pressure detection is performed every time the solder ball is mounted when the flatness of the wafer 1 is not maintained, such as when the wafer 1 is warped. When the flatness of the wafer 1 is maintained but tilted, pressure detection is performed on at least three points on the wafer 1 in order to shorten the tact time. At each point, the plane position (X, Y) and height (Z) of each point is obtained from the descending amount of the suction nozzle 6 from the machine origin, and the inclination of the mounting surface with respect to the ideal horizontal plane is derived by the plane equation (AX + BY + CZ). For each mounting position (X, Y), a method of calculating the height (Z) and determining the descending amount is used.
[0023]
In accordance with the determination of the lowering amount, the control device 11 controls the lifting device 9 to lower the suction nozzle 6 by the lowering amount corresponding to the mounting position and mount it accurately at the mounting position. In addition, the movement to the mounting position (X, Y) in the embodiment is performed by driving the X-axis drive table 2 and the Y-axis drive table 3.
[0024]
In the embodiment, the pressure detection is performed by applying a negative pressure to the suction nozzle 6. However, it goes without saying that the pressure may be positive.
[0025]
【The invention's effect】
The present invention detects a change in the internal pressure of the suction nozzle by bringing the suction nozzle close to the mounting surface while applying a negative pressure or a positive pressure to the suction nozzle without holding a micro work, Since the amount of movement of the suction nozzle to the position is determined, and the movement of the suction nozzle is controlled by the control means based on this amount of movement, and the minute work is mounted on the mounting surface of the object to be loaded. The amount of descent required for mounting can be determined for each mounting point, and the suction nozzle is accurately adjusted with the amount of descent adapted to the mounting location, as shown in Fig. 4, so that the minute work is properly placed on the load. Can be lowered.
[0026]
The effect of the invention of claim 2 is that the amount of movement is obtained at a plurality of locations on the mounting surface, the inclination of the mounting surface is calculated, and the movement of the suction nozzle is controlled by the control means based on the calculation result. If so, it can be lowered with an accurate lowering amount adapted to the mounting position with a small tact time.
[Brief description of the drawings]
FIG. 1 is an explanatory perspective view showing the whole of a small solder ball mounting apparatus according to the present embodiment. FIG. 2 is a graph showing a change in internal pressure. FIG. FIG. 4 is an explanatory diagram showing the relationship between a wafer and a solder ball according to the present invention.
1. . . . . . Wafer 2. . . . . . 2. X-axis drive table . . . . . Y axis drive table4. . . . . . X-Y table5. . . . . . 5. Solder balls . . . . . 6. Suction nozzle . . . . . Pressure detector 8. . . . . . Ball feeder 9. . . . . . Lifting device 10. . . . . Horizontal movement device 11. . . . . Control device 12. . . . . Air tube

Claims (2)

In a micro workpiece mounting device that mounts a micro workpiece on the mounting surface of the mounted object, the suction nozzle that sucks and holds the micro workpiece, the pressure detection means that detects a change in the internal pressure of the suction nozzle, and the suction nozzle are mounted. It is equipped with a moving means for approaching and separating the object mounting surface and a control means for controlling the moving means, and the suction nozzle approaches the mounting surface while applying a negative pressure or a positive pressure to the suction nozzle without holding a minute workpiece. Thus, the change in the internal pressure of the suction nozzle is detected, the amount of movement of the suction nozzle to a position where the predetermined pressure is set in advance is obtained, and the movement of the suction nozzle is controlled by the control means based on this amount of movement to A micro workpiece mounting device characterized by mounting a workpiece. 2. The micro work according to claim 1, wherein the movement amount is obtained at a plurality of locations on the mounting surface, the inclination of the mounting surface is calculated, and the movement of the suction nozzle is controlled by the control means based on the calculation result. On-board equipment.

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