JPH07110456B2 - Wafer bonding method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a wafer bonding method for bonding a wafer to a carrier plate with wax.

[Conventional technology]

Generally, when the surface of the wafer is mirror-finished, the wafer is adhered to the end surface of the carrier plate with wax. For example, after applying molten wax to the surface of a wafer, the wafer is pressed onto a carrier plate and bonded to obtain a uniform bonding surface over the entire surface.

[Problems to be solved by the invention]

However, when the wafer is left in the state of being adhered to the carrier plate in this manner, the wax interposed between the wafer and the carrier plate is solidified and shrunk, but the shrinkage ratio is different in each part of the wafer. Since they are different, there is a problem that the wafer is distorted. In addition, when the carrier plate and the wafer are bonded with wax, air bubbles are likely to be present between the carrier plate and the wafer, and it is difficult to obtain a uniform bonding surface due to the air bubbles.

The present invention has been made in view of the above circumstances, and an object thereof is to be able to remove the strain generated in the wafer bonded to the carrier plate, and to generate bubbles between the carrier plate and the wafer. It is an object of the present invention to provide a wafer bonding method that can obtain a uniform bonding surface over the entire surface and therefore can smoothly perform polishing of the wafer in the subsequent step.

[Means for solving problems]

In order to achieve the above object, the present invention is to press a wafer against a carrier plate and then rotate the wafer by a predetermined angle.

[Action]

In the wafer bonding method of the present invention, when the wafer is pressed against the carrier plate, the wax interposed between the wafer and the carrier plate is cooled, and when the viscosity becomes high, the wafer is rotated. To remove the strain on the wafer and expel air bubbles to the outside.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 6.

5 and 6 show an example of a wafer twisting device, FIG. 5 is a front view, and FIG. 6 is a plan view. This wafer twisting device is provided with a tilting table 2 which is installed on a base 1 so as to descend from left to right in FIG.
A carrier plate elevating mechanism 3 installed on the right end side of the tilt table 2, a twisting machine rotating mechanism 4 standing on the tilting table 2, and a twisting machine 5 supported by the twisting machine rotating mechanism 4. It is composed mainly of and.

The tilt table 2 is provided with a pair of parallel transport roller rows 20 along the longitudinal direction (tilt direction) thereof, and guide rollers 21 are installed at appropriate positions laterally of the both transport roller rows 20. Has been done. The carrier plate CP to which the wafer W is adhered is transferred by the transfer roller row 20 and the guide roller 21. Further, a shock absorbing mechanism 22 and a pair of stoppers 23 are installed in the right end portion of the tilt table 2 near the carrier plate lifting mechanism 3.

The carrier plate elevating mechanism 3 includes a cylinder 30 fixed to the base 1, an upper and lower table 31 movably supported in the up and down direction by the cylinder 30 and a guide mechanism (not shown), and an upper and lower table 31. And 7 cushioning members 32 which are appropriately arranged in the upper and lower portions of the tilt table 2 and lift the carrier plate CP.

In the twisting machine rotating mechanism 4, the mounting plate 41 is rotatably mounted on the upper end of the column 40 standing on the inclined cable 2 and the positioning is stopped at a predetermined angle (every 120 ° in FIG. 6). Is installed as. Then, the mounting plate 41
Is formed by notching three discs at equal intervals.
The twisting machine 5 is attached to each of these notches.

The twisting machines 5 are 4 inches, 5 inches, and 6 inches, respectively.
This is for twisting the wafer W of inch diameter. The wafer W of 4 inch diameter has 8 to 7 wafers on the carrier plate CP.
Similarly, wafers W having a diameter of 5 inches and a diameter of 6 inches are bonded to each other on the carrier plate CP by 6 to 5 pieces, respectively.
One, four or three are glued together. Each of the twisting machines 5 has the same configuration, and as a representative, a wafer W having a diameter of 5 inches will be described with reference to FIGS. 1 to 4.

The twisting machine 5 for the 5-inch diameter wafer W is the mounting plate.
Cylinder 51 mounted on bracket 41 via bracket 50
And is connected to the piston rod 51a of this cylinder 51,
Also, a central shaft 53 which penetrates the mounting plate 41 and the guide bearing 52 and is slidably supported in the vertical direction by the guide bearing 52,
A base plate 54 attached to the tip of the central shaft 53, and arranged so as to face the attachment plate 41 so as to approach and separate from each other,
The upper end is fixed to the mounting plate 41 and the lower end is fixed to the base plate 54.
Slide shaft 56 slidably fitted in the upper guide bearing 55
A drive gear 58 rotatably attached to an intermediate portion of the central shaft 53 via a bearing 57, a twist arm 59 attached to the lower surface of the drive gear 58, and a drill provided in the twist arm 59. A cylinder 61 rotatably connected between one of the plurality of holes 59a and a cylinder receiving member 60 fixed to the upper surface of the base plate 54, and the drive gear 58 penetrating the base plate 54. Three types of pressing and rotating mechanisms 62, 63, which are arranged down to the position
It is mainly composed of 64 and. The pressing rotation mechanism 62 is driven by the driven gear 65 meshed with the drive gear 58.
And a support shaft 67 having the driven gear 65 mounted thereto via a spring pin 66, and supporting the support shaft 67 rotatably around the axis and slidably up and down, and piercing the base plate 54. Guide bearings 6 fitted in two arc-shaped long holes 54a, 54b
8 and a rotation arm 70, which is rotatably connected to the base plate 54 via a pin 69, and rotates the guide bearing 68 about the pin 69 along the elongated holes 54a, 54b. 71 and a pin 7 rotatably attached to an intermediate portion of the rotating arms 70, 71.
2 and cylinders 74 and 75 that are rotatably connected between brackets 73 that are attached to the upper surface of the base plate 54 and that drive the rotating arms 70 and 71, and that are attached to the lower ends of the support shafts 67. The suction pad (pressing portion) 76 is made of silicon rubber and has a hole 76a, and a weight 77 mounted on the suction pad 76. The spring pin 66 is
When an excessive torque is generated between the driven gear 65 and the support shaft 67, the engagement relationship between the two is released. Further, when the guide bearings 68 fitted in the long holes 54a, 54b are located at both ends of the long holes 54a, 54b, the guide bearing 6
The driven gear 65 at the upper end of the support shaft 67 fitted into the gear 8 surely meshes with the drive gear 58.

Further, in the pressing / rotating mechanism 63, an end plate 78 is connected to the upper end of the support shaft 67, and the end plate 78 is connected to the end plate 78.
A locking metal fitting 79 having a substantially inverted U-shaped cross section is engaged with 78 so as to allow a predetermined length of vertical motion, and
79 is connected to the lower end of the piston rod 81a of the cylinder 81 installed via the bracket 80 on the base plate 54, while the guide bearing 68 for supporting the support shaft 67 is fixed to the base plate 54. Since other configurations are the same as those of the pressing and rotating mechanism 62, the same reference numerals are given and the description thereof will be omitted. Further, in the pressing rotation mechanism 64 as well, a guide bearing 68 for supporting the support shaft 67 is fixed to the base plate 54, and other configurations are similar to those of the pressing rotation mechanism 62, so the same reference numerals are given and described. Is omitted.

When performing the method of the present invention using the twisting device configured as described above, that is, when twisting the wafer W adhered by wax on the carrier plate CP,
First, a predetermined twisting machine 5 is positioned above the carrier plate elevating mechanism 3 by the twisting machine rotating mechanism 4 according to the diameter of the wafer W (4,5, 6 inches). Here, when the diameter of the wafer W to be twisted is 5 inches, the twisting machine 5 for 5 inches is disposed above the carrier plate elevating mechanism 3 as described above. At the same time, each cylinder is selected according to the number of wafers W on the carrier plate CP (6 or 5).
74 and 75 are actuated to position the four guide bearings 68 at one end of both ends of the elongated holes 54a and 54b through the rotating arms 70 and 71. That is, when the number of wafers W is 6, in FIG. 2, six driven gears 65 are arranged around the drive gear 58 at equal intervals. Further, when the number of the wafers W is 5, in FIG. 2, the five driven gears 65 except the lowermost driven gear 65 are arranged at equal intervals around the drive gear 58. To be done.
In this case, the pressing rotation mechanism 63 having the lowermost driven gear 65 is the piston rod of the cylinder 81 in FIG.
By pulling up the locking metal fitting 79 at the tip of 81a, the support shaft 67 is lifted together with the end plate 78,
The suction pad 76 at the lower end of the other of the pressing rotation mechanism 62,62,62,6
It is located higher than the suction pads 76 of 2,64. Furthermore, by connecting the tip of the piston rod of the cylinder 61 to one of the plurality of holes 59a of the twist arm 59 attached to the drive gear 58, the twist angle of each suction pad 76 (for example, 30
To 16 °).

In this state, from the left side of FIG. 6, the carrier plate CP, in which a predetermined number of wafers W are adhesively mounted at predetermined positions with wax, is placed on the pair of transport roller rows 20 and on the guide rollers 21 on both sides. It guides and transfers it to the right end of the tilt table 2. When the carrier plate CP stops on the tilt table 2 above the carrier plate lifting mechanism 3 by the shock absorbing mechanism 22 and the pair of stoppers 23, the cylinder 30 of the carrier plate lifting mechanism 3 lifts the upper and lower tables 31. Then, the carrier plate CP is lifted via the cushion material 32 on the upper and lower tables 31, while the cylinder 51 of the twisting machine 5 lowers the base plate 54 together with the central shaft 53, and the pressing and rotating mechanisms 62, 63, 64 are moved. Each suction pad 76 is brought into contact with each wafer W on the carrier plate CP. In this case, each suction pad 76 is pressed against the upper surface of the wafer W by the weight 77 attached to the upper part thereof.

Then, by operating the cylinder 61, the drive gear 58 is rotated by a predetermined angle. As a result, each driven gear 65 meshed with the drive gear 58 rotates by a required twist angle, so that the support shaft 67 on which each driven gear 65 is mounted.
However, it rotates by the above-mentioned twist angle together with the suction pad 76 at its lower end. Therefore, each wafer W is twisted by a required angle by each suction pad 76. As a result, the distortion of the wafer W due to the contraction of the wax between the carrier plate CP and the wafer W is removed, and the bubbles existing between the carrier plate CP and the wafer W are expelled to the outside. In this case, the wafer W is twisted once or plural times by reciprocating the piston rod of the cylinder 61, and at the time of twisting, the wax interposed between the wafer W and the carrier plate CP is cooled and the viscosity is It is desirable from the time when the wax is added to just before the wax is solidified.

〔The invention's effect〕

As described above, according to the present invention, since the wafer is rotated by a predetermined angle after the wafer is pressed and brought into contact with the carrier plate, it is possible to remove the distortion caused by the wax generated in the wafer, and the carrier. There is an excellent effect that a uniform adhesive surface can be obtained over the entire surface without generating bubbles between the plate and the wafer, and therefore the wafer can be polished smoothly.

[Brief description of drawings]

1 to 6 show an embodiment of the present invention,
1 is a front view of the twisting machine, FIG. 2 is a plan view thereof, FIG. 3 is a view taken along the line III-III of FIG. 2, and FIG. 4 is a view taken along the line IV-IV of FIG. FIG. 5 is a front view showing the overall structure, and FIG. 6 is a plan view of the same. W: Wafer, CP: Carrier plate.

Claims (1)

[Claims] 1. A wafer bonding method for bonding a wafer to a carrier plate with wax, which comprises pressing the wafer against the carrier plate and then rotating the wafer by a predetermined angle.