JPS6181474A - Unit for wafer bonding - Google Patents

Abstract

PURPOSE:A wafer is placed on a mounting plate through an adhesive, then the wafer is pressed stepwise from the center toward its periphery to equalize the thickness of the adhesive layer with high precision, further prevent the wafer from being scratched on its back surface. CONSTITUTION:Wafer 2 is placed on a mounting plate 1 through an adhesive 3 and a press 9 contacting with the wafer 2 is pressed stepwise from the center of the wafer toward its periphery.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wafer bonding device for bonding a wafer to a bonding plate with high precision.

Fig. 4 shows an outline of a conventional wafer bonding device, and conventionally, when attaching a wafer 2 to a bonding plate 1 with an adhesive 3, a metal or resin push rod is used manually. 4 to press the wafer 2 and attach it to the attachment plate 1.

In addition, other conventional wafer bonding devices include one in which an artificial support or the like is attached to the tip of the push rod 4 (not shown);
Alternatively, there is a method in which a plurality of wafers set on an adhesive are heated with a heater, and then bonded by applying pressure with a pressure plate at a constant temperature.

However, in the past, in order to improve the adhesion accuracy, skill and long working hours were required.For this reason, in the conventional technology, the thickness of the adhesive layer was made uniform. As a result, the thickness of the adhesive layer 3 becomes wedge-shaped (Fig. 5).
The thickness of the adhesive layer 3 often becomes non-uniform (FIG. 6), and air bubbles enter therein, which adversely affects the processing accuracy after boring.

Furthermore, since an adhesive is used when pressing the wafer manually, the wafer tends to be tilted laterally, and scratches are likely to occur on the back surface of the wafer.

R "January"! An object of the present invention is to provide a wafer bonding device that can uniformize the thickness of the bonding layer with high precision, has good reproducibility, and does not cause scratches on the back surface of the wafer.

41 [Therefore, to achieve this object, the gist of the present invention is to provide a wafer bonding device for attaching a wafer to a bonding plate (herein, a wafer bonding device that attaches a wafer to a bonding plate via an adhesive). The wafer bonding apparatus is characterized in that a wafer is placed on the wafer, and a wafer pressing member that contacts the wafer downward presses the wafer stepwise from the center toward the outer circumference.

. A wafer 2 is placed on a pasting plate 1 with an adhesive 3 interposed therebetween, and a wafer presser 9 that comes into contact with the wafer 2 can press the wafer 2 in stages from the center toward the outer circumference. composition.

Since the wafer presser 9 can press the wafer 2 in stages from the center to the outer circumference, the thickness of the adhesive layer can be made uniform with high accuracy and its reproducibility can be improved. There is no slippage and scratches on the back surface of the wafer 2 can be prevented.

11 and below, the present invention will be described in detail with reference to FIGS. 1 to 3.

The stand 12 is adapted to place the pasting plate 1 thereon, and is equipped with a heater (not shown).

The pressurizing device 8 is disposed above the table 12 via a frame 11, and a downwardly bulging convex pusher 9 is attached to the piston rod 16 thereof.

This wafer pressing body 9 can be raised and lowered by expanding and contracting an air cylinder or a hydraulic cylinder in the pressurizing device 8.

This wafer pressing body 9 is made up of a plurality (four in the embodiment) of hollow cylindrical pressing members 18, 19, 20, 21 that are fitted in sequence.

Each pressing member 18, 19, 20, 21 is made of, for example, a highly rigid metal, and an elastic material such as an artificial leather cap is pasted on the lower surface, and its diameter is set in order as the pressing members located below are made smaller. When the pressing member receives a force from the wafer, the pressing member 21 is inserted into the pressing member 20, the pressing member 20 is inserted into the pressing member 19, and the pressing member 19 is inserted into the pressing member 18 in this order.

In addition, the connection parts of each pressing member 18, 19, 20, 21 are as follows:
It is sealed with a ring-shaped gasket 14 made of rubber or the like, and the lower end surface of the pressing member 21 is closed, and the internal space 15 formed by each pressing member 18, 19, 20, 21 is in a sealed state. .

The internal space 15 is connected to the internal pressure regulating device 10 via a vibrator 10a. This internal pressure adjustment device 10 is
The internal pressure of the internal space 15 can be changed arbitrarily.

Note that the outer shape of the pressing member 18 is made to approximately match the diameter of the wafer 2.

Next, the operation in the configuration described in (h) will be explained.

First, as shown in Fig. 1, the pasting plate 1 is heated to 150 to 155°C by the heater on the stand 12, and the adhesive 3 with low viscosity (for example, viscosity 20 cp) is applied to the -F. Set wafer 2 on.

(c) The internal pressure of the pressing body 9 is adjusted to 0.8 Kq/cm 2 in gauge pressure by the internal pressure adjusting device 10.

Then, the wafer presser 9 is lowered onto the wafer 2 by the pressurizing device 8 at a speed of 5 mm/sec. :
Press with a pressure of 3 kg/'cm2. After the wafer pressing body 9 comes into contact with the upper surface of the wafer 2, the pressing member 21 first presses the center of the I-wafer 2. moreover,
When the wafer pressing body 9 descends, the pressing members 20.19.
As the wafer 2 is pressed in the order of 18, the wafer pressing member 9 is inserted with the pressing members 21, 20, 119, 18 in sequence as shown in FIG. Pressing can be performed in stages, and there is no fear that the wafer 2 will shift laterally when the wafer 2 is pressed, and no scratches will occur on the back surface of the wafer 2.

That is, the adhesive 3 is gradually spread from the center of the wafer 2 toward the outer periphery, and the thickness of the contact layer is thin and uniform, improving its accuracy and leaving no room for air bubbles.

The pressurizing device 8 stops when the entire surface of the wafer 2 is pressed with a predetermined pressure.

Thereafter, as shown in FIG. 3, the wafer presser 9 is raised to its original position, and the bonding of one wafer 2 is completed. The presser body 9, which has returned to its original position, can return from its inserted state to its original state by the action of internal pressure.

Here, a comparison example will be shown between the thickness and accuracy of the adhesive layer of the adhesive 3 obtained by the apparatus of the present invention and the thickness and accuracy of the adhesive layer obtained by the conventional apparatus.

As is clear from Table 1, the apparatus of the present invention
Since the adhesive layer is bonded by pressing stepwise from the center to the outer circumference, the adhesive layer is bonded with an accuracy of 1 μm or less.
It can be seen that the thickness is extremely reproducible and can be set well to a thickness of 1 or less.

By the way, in the present invention, in addition to the conditions of the above-mentioned embodiments,
The heating of the pasting plate 1 may be set at 18 degrees Celsius to 90 to 250'C, and one portion of the adhesive may be applied at 5 to 60 cp. Further, the internal pressure of the wafer pressing body 9 is 0.2 to 1
．． It is set in the range of 9Kg/cm2, and the pressurizing force of the pressurizing device 8 is set to 0.5 to 10! Similar effects can be obtained by setting J/Cm2 and the lowering speed of the pusher 9 to a range of 0.5 to 10 mm/sea.

Further, since the outer shape of the wafer pressing body 9 can be made almost the same as the diameter of the wafer 2, the wafer 2 can be placed on the attachment plate 1.
If a large number of wafer pressers 9 are set and a plurality of wafer pressers 9 are installed so as to correspond to the wafers 2, it is possible to bond a large number of wafers in a short time, which is efficient.

In addition, since the temperature of the adhesive 3 is high and the viscosity of the adhesive 3 is low in the wafer 2 immediately after bonding, warping and deformation are likely to occur again. According to the wafer bonding apparatus of the present invention, as shown in Table 1, since the adhesive layer can be made thin, warping and deformation are small.
By pressing LL-, the adhesion accuracy can be further improved.

Further, although a four-stage wafer pressing body is used in the embodiment, a four-stage, three-stage, or two-stage configuration may also be used.

As is clear from the above explanation, according to the wafer bonding apparatus of the present invention, the thickness of the bonding layer, which has been a problem in the past, can be made uniform with high precision, and its reproducibility is also improved.
However, it has an unprecedented effect in that it does not cause scratches on the backside of the wafer.

[Brief explanation of the drawing]

Figures 1 to 3 show the structure and operation of the 8-place wafer bonding system of the present invention, with Figure 1 being a partially cutaway front view showing the state of the bonding start surface, and Figure 2 being bonded by pressing. 3 is a partially cutaway front view showing the state at the end of bonding, FIG. 4 is a diagram showing a conventional wafer bonding device, and FIG.
This figure and FIG. 6 are diagrams showing a conventional defective adhesion state. 1. Pasting plate 2. Wafer 3. Adhesive 8. Pressure device 9. Wafer pressing body 10. Internal pressure adjustment device 12. ,,,, stand

Claims (1)

[Claims] In a wafer bonding device for bonding a wafer to a bonding plate, the wafer is placed on the bonding plate via an adhesive, and a wafer pressing body that contacts the wafer downward is configured to press the wafer from the center of the wafer. A wafer bonding device characterized by having a configuration in which pressure is applied in stages in the outer circumferential direction.