JP3799519B2 - Screen printing machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a screen printing machine in which cream solder is formed high on a semiconductor wafer and the cream solder is easily removed from a screen mask.
[0002]
[Prior art]
The screen printing machine extrudes cream solder on a screen mask by moving a squeegee, and deposits the cream solder on a substrate or a semiconductor wafer from a mask hole of the screen mask.
[0003]
By the way, in order to mount a chip on a wafer, it is desirable to form a bump at a required height as a ball shape by heating cream solder on the wafer.
[0004]
However, in the case of a conventional screen printing machine, as shown in FIG. 4, the cream solder 101 adhering on the substrate or wafer 100 is deformed after coming out of the mask hole 103 of the screen mask 102, and the height h is reduced. There is a problem that the required height cannot be taken because it becomes lower.
[0005]
Further, the cream solder does not pass smoothly when passing through the mask hole 103 of the screen mask 102, and a part of the cream solder adheres to the inner surface of the mask hole 103, or further wraps around the back surface of the screen mask 102. There was also a problem. In addition, because of this, the screen mask must be frequently cleaned.
[0006]
Conventionally, a special reflow apparatus is used to heat the cream solder, which increases the equipment cost and requires an installation space for providing the equipment.
[0007]
[Problems to be solved by the invention]
The present invention has been made in view of the above points, and the height of the cream solder to be deposited on the semiconductor wafer is held so as not to collapse as much as possible, and the cream solder has mask holes of the screen mask. It is intended to provide a screen printing machine which is designed to pass smoothly when passing, and further does not require a separate reflow device for heating.
[0008]
[Means for Solving the Problems]
Therefore, the gist of the present invention is that a heater is provided on the support table of the substrate so that the substrate is heated to a predetermined temperature before the squeegee printing operation is finished and the cream solder comes out of the mask hole. on the other hand, the top of the screen mask, during the printing operation of the squeegee is retracted from the screen mask, at the same time as the completion of the printing operation of the squeegee, overlying the screen mask, provided in the form covering of an inverted box, further said cover physician body, a suction device for the heater suck flux and air internal when activated, and characterized in that connecting the cooling device for feeding the cool air inside immediately sucked inside the flux and air by the suction device Is in the screen printer.
[0009]
In the above structure, the screen mask may be subjected to heat treatment processing or peeling processing. As a result, when the cream solder passes through the mask holes of the screen mask, it becomes easier to pass smoothly.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic explanatory view, and FIGS. 2 and 3 are operation explanatory views.
[0011]
In the figure, 1 is a squeegee. The squeegee 1 is moved on the screen mask by an apparatus similar to a conventionally known apparatus, and is lifted at the end of printing to leave the screen mask. 2 is cream solder.
[0012]
Reference numeral 3 denotes a screen mask, which is provided with mask holes 4, 4, 4,... In a required pattern. Further, the screen mask 3 is subjected to heat treatment processing or peeling processing in the present embodiment. In the present embodiment uses the SUS of Teflon (registered trademark) processing processed 80 [mu].
[0013]
Reference numeral 5 denotes a semiconductor wafer. Reference numeral 6 denotes a support table for the wafer 5, which includes a heater 7 and heats the wafer 5 to a predetermined temperature at a predetermined timing. In this embodiment, a ceramic heater is used as the heater 7. Further, the support table 6 is lifted and lowered by the base 8 and is moved in the horizontal direction so as to be displaced from the bottom of the screen mask 3 as in the conventional case.
[0014]
9 is a cover that is provided on the top of the screen mask 3 and retracts from the screen mask 3 during the printing operation of the squeegee 1 and covers the screen mask 3 at the same time as the printing operation of the squeegee 1 is finished. is there.
[0015]
A suction device 10 is connected to the cover body 9 and sucks out air in the cover body 9 at an appropriate timing.
[0016]
Reference numeral 11 denotes a cooling device that is connected to the cover body 9 and sends cold air into the cover body 9 at an appropriate timing.
[0017]
Next, the operation of the above embodiment will be described.
When the printing operation of the squeegee 1 is completed, at the same time, the cover 9 is covered on the screen mask 3, while the heater 7 of the support table 6 is activated to raise the temperature of the wafer 5 at a stroke to near 260 ° C. At this time, the suction device 10 is also operated to suck out the flux in the cover body 9 together with the air. Then, immediately after this, the cooling device 11 is operated to send cold air into the cover body 9.
[0018]
As described above, since the wafer 5 is heated to a high temperature close to 260 ° C., the cream solder 2 contracts and is further cooled from the top by cold air to maintain its height, It is possible to smoothly pass through the mask hole 4 without resistance from the screen mask subjected to the peeling treatment. As a result, the cream solder 2 is completely removed in the form of the mask hole 4 and is instantaneously cooled from the upper side by the cold air. Therefore, the cream solder 2 begins to harden and retains its shape before it loses its shape. Therefore, as shown in FIG. 3, the height H of the cream solder 2 is maintained higher than the conventional one, and the required height can be taken.
[0019]
Further, as described above, since the cream solder 2 can be easily removed from the mask hole 4 of the screen mask 3, a part of the cream solder 2 does not adhere to the mask hole 4 or wrap around the back surface of the screen mask 3. . Therefore, it is not necessary to clean the screen mask as frequently as in the prior art. When the screen mask is subjected to heat treatment or peeling treatment as in the present invention, the omission is further improved and the effect is further increased.
[0020]
In addition, since the heater 7 for heating is provided on the wafer support table 6, it is not necessary to install a separate reflow device. Therefore, the cost for providing the reflow device can be saved and the installation space can be saved.
[0021]
【The invention's effect】
Since the present invention has the above-described configuration and operation, the height of the cream solder to be deposited on the semiconductor wafer can be maintained higher than the conventional level and the required height can be obtained.
[0022]
Further, when the cream solder passes through the mask hole of the screen mask, it passes smoothly. Therefore, unlike the conventional case, a situation in which a part of the cream solder remains attached to the inner surface of the mask hole or further wraps around the back surface of the screen mask does not occur, and it is not necessary to frequently clean the screen mask. In addition, when the screen mask is subjected to heat treatment or peeling treatment, the omission is further improved, and this effect is further enhanced.
[0023]
Moreover, since it is not necessary to install a reflow apparatus separately, the cost for providing this can be saved and the installation space can also be saved.
[Brief description of the drawings]
FIG. 1 is a schematic explanatory diagram of the present invention.
FIG. 2 is a diagram for explaining the operation of the present invention, and shows a state in which cream solder is filled in a mask hole of a screen mask.
FIG. 3 is a diagram for explaining the operation of the present invention, showing a state in which the wafer is separated from the screen mask.
FIG. 4 is an explanatory diagram of a screen mask and cream solder in the case of using a conventional screen printing machine.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Squeegee 2 Cream solder 3 Screen mask 4 Mask hole 5 Semiconductor wafer 6 Wafer support table 7 Heater 8 Base 9 Cover 10 Suction device 11 Cooling device

Claims (1)

A squeegee printing operation is completed by installing a heater on the substrate support table, and the solder is heated to a predetermined temperature before cream solder comes out of the mask hole. retracted from the screen mask, at the same time as the completion of the printing operation of the squeegee, overlying the screen mask, provided in the form covering of an inverted box, further said cover member, the inner portion when the heater is operated A screen printing machine comprising: a suction device that sucks out flux and air; and a cooling device that sends cold air into the interior immediately after the suction of the flux and air inside the suction device.

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