JPH04142018A - Apparatus for sticking wafers - Google Patents

Abstract

PURPOSE:To stick both wafers with good sealability by deforming a surface to be stuck of a member to be from a projecting curve into a flat surface and bringing two wafers gradually into contact with each other from an approxi mately center toward a peripheral part. CONSTITUTION:A surface to be stuck of at least one of a pair of members 11, 12 to be stuck before sealing is a projecting curve, while two wafers 1, 2 are held on the surfaces 13, 14 to be stuck. Both wafers 1, 2 are brought into contact approximately at the center by a driving means, and the surface to be sticked is transformed from the projecting curve to a flat face by heaters 19, 20 being deformation applying means, whereby both wafers 1, 2 are gradually brought into contact with each other from approximately the center toward a periphery. Thus it is possible to stick two wafers 1, 2 to each other with good sealability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a wafer bonding apparatus for bonding two wafers together when manufacturing a multilayer device.

[Prior Art] Multilayer devices, such as SOI (Silicon
One of the methods for manufacturing a semiconductor laminated substrate such as an on-in-layer structure is to bond two wafers together.

FIG. 5 shows a conventional example of a conventional wafer bonding apparatus. After aligning two wafers 1 and 2, a pair of rollers 3.4 presses both wafers 1 and 2. , both rollers 3.4 are rotated from one end to the center and further to the other end to bring the wafers 1 and 2 into close contact with each other.

[Problem to be solved by the invention] When bonding two wafers together in the production of multilayer devices, two important items are improving the adhesion between both wafers and ensuring accurate alignment of both wafers. It becomes a point.

However, in the case of the conventional example shown in FIG. 5, the two wafers 1.2 which have been brought into surface contact in advance are brought into close contact with each other by the rotational movement of both the rollers 3.4, so air is trapped between the two wafers 1.2. bubbles are likely to form. Also, after both rollers 3.4 have passed, there is no pressing force on both wafers 1.2 (
As a result, incomplete bonding may occur between the wafers 1 and 2, or both wafers 1 and 2 may easily separate from the outer periphery. As described above, in the past, there was a problem that the adhesion between both wafers 1.2 was not necessarily sufficient.

Furthermore, the structure for rotationally moving the pair of rollers 3.4 is as follows:
Since a lateral force acts on both wafers 1.2, if the pressing force or rotational force of both rollers 3.4 unexpectedly differs, a relative lateral shift will occur in both wafers 1 and 2. For this reason, there was a problem in that the alignment of both wafers 1 and 2 was likely to go out of order.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a wafer bonding apparatus that can bond two wafers together with good adhesion and accurate alignment.

C Means for Solving the Problem] In order to achieve the above object, a wafer bonding apparatus according to the first invention includes a pair of bonding members each having a pair of bonding surfaces that respectively hold two wafers, A pair of affixing members, one affixing surface of which is deformable into a convex curved surface and a flat surface, and the other affixing surface of which is a deformable or fixed flat surface; a driving means that moves at least one of the pair of attachment members to bring substantially centers of the wafers held on the attachment surfaces into contact with each other; and a deformable one of the attachment surfaces that respectively hold the wafers. and deformation applying means for deforming the sticking surface from a convex curved surface to a flat surface.

Further, the wafer bonding device according to the second invention includes a pair of bonding members each having a pair of bonding surfaces for holding two wafers, one of the bonding surfaces being deformable into a convex curved surface and a flat surface. a pair of sticking members, the other of which is configured of a flat surface that can be deformed into a convex curved surface and a flat surface, or a fixed flat surface; 1. a detection means for detecting a mark on each wafer; and a storage means for storing the position of each mark on both wafers detected by the detection means; a drive means for moving at least one of the pair of attachment members to adjust the relative positions of the wafers held on the attachment surfaces so that substantially centers of the wafers come into contact with each other; control means for aligning the two wafers by controlling the drive means based on the position data of each mark on the two wafers; and deformation applying means for deforming the surface from a convex curved surface to a flat surface.

In addition, it is preferable that the sticking member having the deformable sticking surface is formed of a shape memory alloy, and the deformation imparting means is constituted by a heating means.

Further, the sticking member having the deformable sticking surface may be formed of an elastic body, and the deformation imparting means may be constituted by pressure bonding means.

[For production]

According to the wafer bonding apparatus of the first invention configured as described above, at least one of the bonding surfaces of the pair of bonding members is a convex curved surface before the bonding, and two wafers are attached to these bonding surfaces. Each is retained. By bringing the substantially centers of both wafers into contact with each other by the driving means and by deforming the attachment surface from a convex curved surface to a flat surface by the deformation applying means, both wafers are gradually brought into close contact from the substantially center to the outer periphery.

Further, according to the wafer bonding apparatus of the second invention, the position of each mark on both wafers detected by the detection means is stored by the storage means, and the position data of each mark stored in the storage means is stored. , the drive means is controlled by the control means.

Thereby, the alignment of both wafers can be performed extremely accurately before the two wafers are brought into close contact with each other by the pair of attachment members.

〔Example〕

Hereinafter, an embodiment of a wafer bonding apparatus to which the present invention is applied will be described with reference to FIGS. 1A to 4.

First, FIGS. 1A and 1B show the state before and when two wafers are brought into close contact with each other by a pair of sticking members, respectively.

The wafer bonding apparatus includes a pair of bonding members 11 and 12. These application members 11, 12 are of identical construction and are arranged opposite to each other.

The attachment parts 1.12 are formed in the shape of a disk from a shape memory alloy, and their front side serves as an attachment surface 13.14 for holding the wafer 1.2. Note that the outer diameter of the attachment member 11.12 is approximately 10 mm larger than the outer diameter of both wafers 1.2.

As shown in FIG. 1A before contact, under the normal temperature of the environment in which the device is used, the application members II and 12 are deformed so that their application surfaces 13 and 14 become convex curved surfaces. There is. Ideally, these convex curved surfaces are spherical surfaces, but in this embodiment they are cylindrical surfaces. Note that in the drawings, the curvature is exaggerated, and in reality, the difference in height between the center and the outer periphery of the attachment surface 13, 14 is about 2 to 3W.

In addition, as shown in FIG. 1B when they are adhered, the restored shape memorized in the shape memory alloy attachment members 11.12 is such that their attachment surfaces 13.14 are flat surfaces.

In addition, there is a suction hole 1 for vacuum suction in the pasting member ll, 12.
5.16 are provided, which are perforated in the application surface 13.14. The attachment members 11.12 are supported by support members 17.18 so that their deformation is not hindered. Furthermore, a heater 19.20 is attached to the support member 17.18 on the back side of the pasting member 11.12 as a heating means serving as a means for imparting deformation.

Then, as shown in FIGS. 2A to 2D, the support member 1
7.18 are each mounted horizontally on the drive means 21.22. By means of these drive means 21.22, the support members 17.18 (i.e. the application members 11.12) are moved on the left and right a
It is configured to be movable in the up-down direction, up-down direction, front-back direction (direction perpendicular to the plane of the paper, not shown), and rotatable in the direction of arrow C in a horizontal plane.

Next, the operation of the wafer bonding apparatus configured as described above will be explained.

First, as shown in FIG. 1A, before adhesion, the pasting member 11
．． 12 are both deformed so that their application surfaces 13 and 14 are convex curved surfaces. The deformation can be achieved by incorporating the deformation drive unit inside the support member 17, 18, or by incorporating the deformation drive unit into the support member 11.
12 can be crimped onto a deformation mold. The wafer 1.2 is placed on the attachment surface 13.14 of the deformed attachment member 11.12 and held by vacuum suction through the suction holes 15.16. As a result, the wafer 1.2 is deformed into a convex shape along the application surface 13.14.

After alignment of the wafer 1.2, which will be described later, the application member 11.12 is moved and approached by the drive means 21.22. When the centers of the wafers 1.2 come into contact, the movement of the application member 11.12 is stopped. The pasting member 1112 is then heated by the heater 9.20.

When the specific temperature is reached, the attachment member 11.12 is deformed back to its memorized shape, ie, the attachment surface 13.14 becomes a flat surface, as shown in FIG. 1B.

In this way, by changing the attachment surface 13.14 of the attachment member 11.12 from a convex curved surface to a flat surface, the two wafers 1.2 are brought into close contact with each other, and the attachment surface 13.14 is completely flat. The close contact is complete when this happens.

According to this close contact operation, as the attachment surfaces 13.14 deform, both wafers 1.2 are gradually attached closely from the center to the outer periphery, so that air is trapped between both wafers 1.2 and bubbles are formed. will not occur.

In addition, since a pressing force is applied to the entire wafers 1.2 when the wafers 1.2 are brought into close contact with each other, it is possible to prevent incomplete bonding between the wafers 1.2 and separation of the wafers 1 and 2 from the outer periphery. do not have. Furthermore, since no lateral force acts on both wafers 1.2, there is no relative lateral displacement of both wafers 1.2.

Next, alignment of two wafers will be explained with reference to FIGS. 2A to 4.

First, as shown in FIGS. 2A to 2D, a mounting member 30 made of a rigid body is placed near the bonding position, and a pair of cameras 31. 32 are mounted facing each other. These cameras 31 and 32 can be, for example, CCD cameras. As shown in FIG. 2A, the camera 31 images the wafer 2 held on the attachment surface 14, and as shown in FIG. 2B,
The camera 32 images the wafer 1 held on the attachment surface 13.

As shown in FIG. 3, two marks P and Q for alignment are provided in advance on the bonding surfaces of both wafers 1.2. Note that these marks P and Q may be formed by wafer exposure using a stepper (reduction projection exposure device) or the like.

As shown in FIG. 4, the image signals from the cameras 31 and 32 are input to the control section 40, sent from the control section 40 to the storage section 41, and stored in different storage areas of the storage section 41. Ru. For example, an image memory can be used as the storage unit 41. Then, the control unit 40 controls the storage unit 4
The position data of the marks P and Q of both wafers 1.2 stored in the drive means 21.1 are compared, and based on this, the drive means 21.
A control signal is sent to 22.

Next, the operation of the wafer bonding apparatus configured as described above will be explained.

First, as shown in FIG. 2A, when aligning the wafer 2, the sticking member 11 and the wafer 1 are retracted by the driving means 21, the wafer 2 is imaged by the camera 31, and the image is stored in the storage unit 41. .

Further, as shown in FIG. 2B, when aligning the wafer 1, the sticking member 12 and the wafer 2 are retracted by the driving means 22, the wafer 1 is photographed by the camera 32, and the image is stored in the storage section 41. .

Then, the control unit 40 uses the position data of the marks P and Q of the wafer 1 stored in the storage unit 41 and the mark Q of the wafer 2,
The control signal is compared with the position data of P, and a control signal is sent to the driving means 21, 22 based on the position data. As a result, as shown in FIG. 2C, the pasting member 1112 is moved by the drive means 21.22, and both wafers 1 and 2 are aligned.

In this way, since it is based on the position data of the marks P and Q on both wafers 1.2, alignment of both wafers 1.2 can be performed extremely accurately.

Furthermore, based on the position data, alignment is not limited to aligning the positions of the marks P and Q on both wafers 1.2, but can also be performed such that the positions of the marks P and Q are separated by a predetermined distance. can. In this case, the distance value may be input to the control unit 40 from the outside. Furthermore, pasting side 1
The lateral displacement error of both wafers 1.2 on 3.14 appears as position data, and the installation error of cameras 31 and 32 can also be input as position data in advance, so if the position data is used as the basis, these errors can be absorbed. be able to. Note that since the attachment members 11.12 are rotatable in the direction of arrow C in the horizontal plane, and two marks P and Q are provided on both wafers 1.2, alignment can also be performed by rotating both wafers 1.2 in the horizontal plane. It can be carried out.

After the alignment as described above, as shown in FIG. 2D, the sticking member 11.12 is brought closer by the drive means 20.21 to bring both wafers 1.2 into contact with each other. and,
Both wafers 1.2 are brought into close contact as described above with reference to FIG. 1B.

Although one embodiment of the present invention has been described above, the present invention is not limited to the embodiment, and various effective changes can be made based on the technical idea of the present invention.

For example, in the embodiment, both attachment surfaces are configured to be deformable into a convex curved surface and a flat surface, but one may be a fixed flat surface. Further, in the embodiment, a pair of drive means for moving the pair of sticking members, respectively, is provided, but this driving means may be one that moves one of the sticking members.

In addition, when the attachment member is formed of a shape memory alloy,
The heating means serving as the deformation imparting means is not limited to the heater of the embodiment, but may be a heating chamber or the like for heating the entire body.

Further, it is possible to employ a configuration in which the sticking member is formed of an elastic body that can be elastically deformed, and the sticking surface is deformed into a convex curved surface and a flat surface. In this case, pressure bonding means is used as the deformation imparting means.

[Effects of the Invention] As explained above, according to the first invention, by changing the sticking surface of the sticking member from a convex curved surface to a flat surface, two wafers can be moved from approximately the center to the outer periphery. It can be gradually brought into close contact.

Therefore, it is possible to effectively prevent the generation of air bubbles between the two wafers, the generation of incompletely bonded parts, peeling of the outer periphery, and lateral displacement of both wafers, and it is possible to bond both wafers together with extremely good adhesion. I can do it.

Further, according to the second invention, by moving the sticking member based on the position data of the marks on the two wafers, both wafers can be aligned with extremely high precision. Moreover, alignment based on position data is
In addition to having a large degree of freedom in adjustment, it is also possible to absorb errors in lateral displacement of both wafers on the attachment surface, mounting errors in the detection means, and the like.

Therefore, in combination with the above-mentioned bonding with good adhesion, both wafers can be aligned and bonded extremely accurately.

[Brief explanation of the drawing]

1A to 4 show an embodiment of a wafer bonding apparatus to which the present invention is applied, in which FIG. 1A is a front view of a pair of bonding members before wafer bonding, and FIG. 1B is a front view of a pair of bonding members before wafer bonding. FIGS. 2A to 2D are front views of the entire apparatus for explaining wafer alignment, FIG. 3 is a plan view of the wafer, and FIG. 4 is a block diagram showing the configuration of the alignment control system. be. FIG. 5 is a schematic perspective view of a conventional example of a wafer bonding apparatus. In addition, in the symbols used in the drawings, 1.2... Wafer 11.12... Pasting member 13.14... Pasting surface 19.20... ... Heater 21.22 ... Drive means 31.32 ... Camera 40 ... Control section 41 ...
......Memory section P, Q...
...It's a mark.

Claims (4)

[Claims] (1) A pair of attachment members each having a pair of attachment surfaces that hold two wafers, one attachment surface being deformable into a convex curved surface and a flat surface, and the other attachment surface being convex. A pair of affixing members configured of a flat surface that can be deformed into a curved surface and a flat surface or a fixed flat surface, and at least one of the pair of affixing members is moved to attach the wafers held respectively to both of the wafers. A wafer bonding apparatus comprising: a drive means for bringing the two wafers into contact with each other at substantially the center; and a deformation imparting means for deforming a deformable bonding surface of both of the bonding surfaces holding the wafers from a convex curved surface to a flat surface. (2) A pair of attachment members each having a pair of attachment surfaces that hold two wafers, one attachment surface being deformable into a convex curved surface and a flat surface, and the other attachment surface being convex. a pair of affixing members configured with a fixed flat surface that can be deformed into a curved surface and a flat surface, and a detection means that detects marks provided in advance on both of the wafers respectively held on both of the affixing surfaces; a storage means for storing the position of each mark on the two wafers detected by the detection means; and a relative position of the two wafers respectively held on the two adhesion surfaces by moving at least one of the pair of adhesion members. a drive means for bringing the wafers into contact with each other at approximately their centers; and a drive means for controlling the drive means based on positional data of each mark on the two wafers stored by the storage means to align the two wafers. A wafer bonding apparatus comprising: a control means for controlling the wafers; and a deformation imparting means for deforming a deformable bonding surface of the bonding surfaces holding the wafers from a convex curved surface into a flat surface. (3) The wafer bonding apparatus according to claim 1 or 2, wherein the bonding member having the deformable bonding surface is formed of a shape memory alloy, and the deformation imparting means is constituted by a heating device. (4) The wafer bonding apparatus according to claim 1 or 2, wherein the bonding member having the deformable bonding surface is made of an elastic body, and the deformation imparting means is configured by a pressure bonding device.