JPH03280525A - Adhesion of wafer and device therefor - Google Patents

Abstract

PURPOSE:To make constant a pressing force and to increase the evenness of a wax layer under the lower surfaces of wafers by a method wherein pressing to the wafers is performed by headers which are mechanically rolled. CONSTITUTION:A cylinder 8 is made to operate, a load plate 5 is descended, heated headers 6 are respectively made to negotiate with the outside end edges of wafers 22 and the wafers 22 are put in a state that they are applied a load. A motor 36 is driven and when a swinging plate 7 is rotated via a gear 17, spherical heads 21 of swinging arms 20 are respectively moved in individual long holes 35 from the outside to the inside, curved surface parts 19 of the headers 6 are rolled and each pressing point using the headers 6 goes being moved from the outside end edge to the inside end edge of each wafer 22. The plate 5 and other leads are always applied to the wafers 22 via rotating rollers 24 and the wax 39 existing under the lower surfaces of the wafers 22 is squeezed from the outside to the inside.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides an adhesive method and method for fixing a semiconductor wafer (hereinafter abbreviated as "r-wafer") to a ceramic plate during mirror polishing. The present invention relates to an apparatus used directly for carrying out the bonding method.

(Prior Art) A wafer is bonded to a ceramic plate with wax and subjected to mirror polishing. The thickness of the wax layer existing on the lower surface of the wafer is related to the finishing accuracy in the mirror polishing. In other words, if the wax layer is thick, the mirror-polished surface may have uneven thickness, or the parallelism may be poor, resulting in unevenness.

Therefore, conventionally, care has been taken to reduce the thickness of the wax layer existing on the lower surface of the wafer as much as possible, and wax is manually infiltrated into the lower surface of the wafer. in particular,
After infiltrating the wax into the bottom surface of the wafer, the worker uses a jig to squeeze out the wax present on the bottom surface of the wafer, or presses the flat precision surface of a press against the top surface of the wafer to remove the wax present on the bottom surface of the wafer. I was squeezing out the wax. The thickness of the wax layer made thin by these means is 0.5p to 1.5p. It was OIL.

(Problems to be Solved by the Invention) As mentioned above, there are variations in the thickness of conventional wax layers, which causes variations in the finishing accuracy of mirror polishing, and it is difficult to make the wax layer thinner and more uniform. A means to do so was desired.

Furthermore, in the case of manual processing, the wax is heated to 150-160°C during squeezing, but due to the effects of this heat, there are limits to the size and weight of the ceramic plates used, and as a result, the number of wafers attached is limited. In addition to being limited to a maximum of 5 wafers, if the wafer has a large diameter (for example, 5 inches φ), the wax layer thickness for the - wafer
There are problems such as not being uniform in each part.

The present invention has been made with the object of providing a means that does not have the above-mentioned problems.

(Means for solving the problem) That is, the wafer bonding method which is the first invention of the present application is as follows:
A wafer bonding method in which a wafer is placed on a ceramic plate, wax is infiltrated into the lower surface of the wafer, and the wax is heated while pressing the upper surface of the wafer to fix the wafer to the ceramic plate. Pressing is carried out using a header with a curved surface while mechanically rolling the header, and by squeezing out excess wax present on the underside of the wafer, the wax layer on the underside of the wafer is made as thin as possible. The bonding device according to the second invention includes a load plate that is moved up and down by the operation of a cylinder, a header that is protruded from the lower surface of the load plate to press the upper surface of the wafer, and a load plate that is configured to tilt the header. The header includes a swinging plate that is attached to the upper part of the plate and can be rotated reciprocally within a certain angle range, the header has a curved surface portion on the lower surface and a swinging arm that projects upward on the upper surface, and the load plate is , a regulating hole into which the center portion of the swing arm is loosely fitted to permit linear reciprocating movement of the swing arm in only one direction, and the swing plate is loosely fit into the top portion of the swing arm; It has a long hole that allows the top rocking plate to move in the radial direction.

(Function) According to the first aspect of the invention, since the wafer is pressed by a mechanically rolling head, the pressing force is always constant and the wax layer on the lower surface of the wafer becomes uniform.

Further, according to the second invention, the header protruding below the load plate presses the top surface of the wafer, and at the same time, the swinging arm is tilted by rotating the swinging plate within a certain angle range, The pressure point on the top surface of the wafer of the curved header is moved from one end to the other, thereby squeezing out the wax present on the bottom surface of the wafer.

(Example) Hereinafter, the present invention will be explained based on the accompanying drawings.

Fig. 1 is a longitudinal sectional view showing an embodiment of the device according to the present invention, Fig. 2 is an enlarged sectional view of the same essential part, Fig. 3 is an enlarged sectional view taken along the line m-■ in Fig. 2, and Fig. 4 is an enlarged sectional view of the same main part. Supplementary explanatory diagram regarding the shape of the ivy, Fig. 5 is a v-■ arrow view in Fig. 2, Fig. 6
The figure is an explanatory diagram of movement of a load point with respect to a wafer, and FIGS. 7(a) and 7(a) are explanatory diagrams for carrying out the present invention.

First, the bonding device will be explained.

As shown in FIG. 1, the adhesive device of the present application has a gate post 2 erected on a pedestal 1, a temperature-adjustable cushion plate 3 is placed on the pedestal 1, and the gate post 2, the pedestal 1, and a roof plate are placed on the pedestal 1. A load plate 5, a header 6, and a swing plate 7, which will be described later, are arranged in the space divided by 4.

8 is a cylinder attached to the center of the roof plate 4, and the operating rod 9 of the cylinder 8 is made to protrude downward;
The above-described load plate 5 is attached to the lower end of the operating rod 9. In other words, the load plate 5 is configured to move up and down by the operation of the cylinder 8. The upper part of the load plate 5 has a small diameter (hereinafter, the core part is referred to as the "boss part 5aJ") and the lower part has a large diameter (hereinafter, the core part is referred to as the "boss part 5aJ"). "flange part 5"
b), and an upper plate 10 is attached to the upper surface of the plate 5 to transfer the load.
A leg 11 is attached to the end edge of the frame in a hanging manner. A hook 12 for hooking the operating rod 9 is fixed on the upper plate 10, and screw holes 15 are formed in the upper plate 10 so that a plurality of weights 13 can be fixed with bolts 14. There is. Reference numeral 16 denotes a bearing for a gear 17, which will be described later, and the bearing 16 is also attached to the upper plate l.

installed on top. The above-mentioned leg 11 is engaged with a guide piece 18 attached to the gate post 2, so that the load plate 5 cannot be rotated unintentionally.

The header 6 is provided to protrude from the lower surface of the load plate 5 described above. This header 6 has a heat retention function of 150 to 160° C., has a curved surface 19 on the lower surface, and has a prismatic swinging arm 20 protruding from the top surface, with a spherical head on the top of the swinging arm 20. It is equipped with 21. However, the curved surface 19 is formed only in the central portion, and the edge portions are formed to be straight lines when viewed from the side. This is because if the surface up to the edge is curved, line pressure will be applied to all parts of the wafer 22, causing cracks 23 at the end of the wafer 22, as shown in FIG.

A rotating roller 24 is attached to the lower part of the swing arm 20, and the rotating roller 24 has the role of receiving and stopping the load of the load plate 5. Further, 25 is a retaining pin attached to the swing arm 20 slightly above the rotating roller 24.

The header 6 including the swing arm 20 is attached to the load plate 5 via a frame 26 .

Specifically, a receiving hole 27 is formed on the lower surface of the load plate 5, the frame 26 is fitted into the receiving hole 27, and the top plate 2 of the frame 26 is inserted into the receiving hole 27.
8 and the bottom of the receiving hole 27 (the upwardly recessed part in the drawing) are connected by a wire 29 and a splinter 30, and the retaining pin 25 is present above the ring body 28 of this frame body 26, and the top plate 28
In other words, the header 6 is mounted below the rotating roller 24 (in other words, with the retaining pin 25 and the rotating roller 24 sandwiching the top plate 28).

Reference numeral 34 denotes a regulation hole penetrating the flange portion 5b of the load plate 5, and the regulation hole 34 is a long hole facing the center of the load plate 5, similar to the slot holes 32 and 33 described above.
The prismatic swing arm 20 of the header 6 is inserted into the regulation hole 34.
or inserted. Therefore, the swing arm 20 is configured to swing toward the center of the load plate 5.

The swing plate 7 is rotatably attached to the boss portion 5a of the load plate 5, and is driven by a gear 17 driven by a motor 36.
It is meshed with. A long hole 35 is formed in the swing plate 7, with one end approaching the center of the swing plate 7 and the other end facing away from the center of the swing plate 7.
0 spherical head 21 is fitted. That is, by driving the motor 36, the swing plate 7 is moved at a predetermined angle (an angle in the range in which the spherical head 21 or the elongated hole 35 is moved from one end to the other end) via the gear 17.
There is a configuration in which the spherical head 21 is moved reciprocally and linearly in the radial direction of the rocking plate 7.

Next, the implementation of the invention related to the method of the present application using the above-mentioned inventive device will be described.

First, 12 4-inch φ wafers 22 or 8 5-inch φ wafers 22 are placed on a predetermined position on the ceramic plate 38 and wax 39 is injected, and the wax 39 permeates the lower surface of the wafer 22. (See Figure 7).

On the other hand, the cylinder 8 is driven to raise the load plate 5, the frame 26 attached to the load plate 5, and the header 6 suspended on the frame 26 by about 125 mm, and the spherical head 21 is inserted into the elongated hole. Set it on the edge near the outside of 35,
The wax-infiltrated ceramic plate 38 prepared above is aligned and set on the cushion plate 3 heated to 150 to 160° C., and a cushioning material 40 is applied to the upper surface of the wafer 22. This cushioning material 40 is made of paper with a pressure of approximately 80 JL, and has two roles: to provide a pressure gradient to the pressing force due to the curved surface 19, and to prevent foreign matter from entering.

Next, the cylinder 8 is activated to lower the load plate 5, and each header 6 heated to 150 to 160° C. is brought into contact with the outer edge of each wafer 22, so that the wafer 22 is loaded. . Here, when the edge of the wafer 22 is subjected to a pressing force, cracks 23 are likely to occur, but in this case, the wafer 22 is pressed by the flat part of the header 6, and no cracks 23 occur.

Then, the motor 36 is driven and the gear 17 is intervened to rotate the swinging plate 7. As a result, the spherical head 2 of the swinging arm 20
1 moves inside the elongated hole 35 from the outside to the inside and connects to the header 6.
The curved surface portion 19 of the wafer 22 rolls, and the pressing point by the header 6 moves from the outer edge of the wafer 22 to the inner edge. During this process, the load on the load plate 5 and other loads is always applied to the wafer 22 via the rotating roller 24. Therefore, the wax 39 on the bottom surface of the wafer 22 (heated from the cushion plate 3 and the header 6) The wax 39) with improved properties is squeezed out from the outside to the inside.

Note that the level L of the load applied to the rotating roller 24 changes when the header 6 is transferred, but in the above embodiment, the frame 26 is attached to the load plate 5 with wires 29 and springs 30, and as a result, When the level L changes, the splinter 30 expands and contracts, but the load itself does not change.

If the pressing point moves inward in this way, wafer 2
The wax layer on the lower surface of 2 is 0.4p or less, and the cylinder 8 is operated to raise the load plate 5 and header 6 to the upper limit position, and the motor 36 is driven in reverse to rotate the swing plate 7 in the reverse direction. and return the header 6 to its original position.

The movement of the device up to this point constitutes one cycle, which takes about 90 seconds. Note that the movement of the above device for one cycle can be automatically performed using a sensor or a limit switch.
It is also possible to use a configuration in which a buzzer notifies the end of the cycle.

(Effects of the Invention) As explained above, according to the invention of the present application, it is possible to reduce the thickness of wax to 0.4 μL or less without variation, and as a result, the processing accuracy in mirror polishing is significantly improved. . According to the apparatus of the present invention, it is possible to save labor and increase the amount of adhesion processing.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view showing an embodiment of the device according to the present invention, Fig. 2 is an enlarged sectional view of the same essential parts, Fig. 3 is an enlarged sectional view taken along the line -■ in Fig. 2, and Fig. 4 is a header. Supplementary explanatory diagram regarding the shape of Figure 5 is a v-■ arrow view in Figure 2, Figure 6
The figure is an explanatory diagram of movement of a load point with respect to a wafer, and FIG. 7C (0) is an explanatory diagram for carrying out the present invention. 5... Load plate 7... Rocking plate 20... Rocking arm 35... Long hole 39... Wax 6... Header 8... Cylinder 22... Wafer 38... ceramic plate

Claims (2)

[Claims] (1) A wafer bonding method in which a wafer is placed on a ceramic plate, wax is infiltrated into the lower surface of the wafer, and the wax is heated while pressing the upper surface of the wafer to fix the wafer to the ceramic plate. Pressure is applied to the upper surface while mechanically rolling the header with a curved header to squeeze out excess wax on the lower surface of the wafer, thereby making the wax layer on the lower surface of the wafer as thin as possible. Characteristic wafer bonding method. (2) a load plate that is moved up and down by the operation of a cylinder; a header that projects from the bottom surface of the load plate to press the top surface of the wafer; and a header that is attached to the top of the load plate to tilt the header; the header has a curved surface on its lower surface and a swinging arm projecting upward on its upper surface; The rocking plate has a regulation hole into which the center part is loosely fitted to allow the rocking arm to move in a straight line in only one direction; A bonding device characterized by having a long hole that moves the plate in the radial direction.