JP2002270679A - Thin board deforming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an inexpensive thin board deforming device that has a simple structure and can obtain high accuracy, even if the device is rotated at a high speed. SOLUTION: When the thin board mounting device 22 of this thin board deforming device 23 deforms a wafer 20 to make it into an arbitrary surface form, a chuck plate 1 is deformed, following the rear-surface form of the wafer 20 and vacuum-holds the wafer 20. Simultaneously, struts 3 of a deformation- maintaining device 21 are fixed, based on a vacuum pressure and maintain the deformation of the chuck plate 1. Thereafter, the surface form of the wafer 20 is maintained by means of the deformation-maintaining device 21, which is not provided with any device used for deforming the chuck plate 1 by removing the thin board mounting device 22 from the surface of the wafer 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a silicon wafer,
Also, the present invention relates to an apparatus used for processing the surface of a thin plate such as a device surface formed on a silicon wafer, and more specifically, an apparatus for processing while maintaining a state in which the thin plate is deformed into an arbitrary surface shape. The present invention relates to a thin plate deforming device used for a device.

[0002]

2. Description of the Related Art Conventionally, the final finishing of a silicon wafer,
Alternatively, the flattening process of each interlayer film generated in the process of forming devices on the surface of a silicon wafer such as an LSI is performed by bringing a wafer held by a chuck of a constant pressure type into contact with a soft grinding pad and a slurry. A polishing method called free polishing, which is called polishing, in which the surface is polished by relative movement while supplying a working liquid mixed with abrasive grains, is used.

[0003]

In recent years, however, semiconductor chips have been developed in order to improve the degree of integration.
While the design rules are becoming finer, the wafer size is increasing over several years in order to improve production efficiency, and not only the surface of each device forming the LSI is flattened, but also the silicon used as the LSI base material. It has become an important technical issue, including flattening of the wafer itself. However, in the currently adopted processing method using loose abrasives, the chuck for fixing the wafer is intended for constant pressure pressurization,
Since the chuck itself does not have the ability to maintain its shape, and the polishing pad is also soft and has a low shape correction ability, it is a processing method that is difficult to flatten in principle. Technology innovation is desired.

For this reason, in principle, instead of a chuck of a constant pressure and pressurization type, which can easily perform flattening processing with higher precision, a chuck for maintaining and fixing the shape of a wafer and a grindstone for fixing abrasive grains are used. Attempts have been made in part to use a processing method using fixed abrasive grains for cutting. However, even in this method, there is a drawback that the difference in thickness of the wafer itself appears as a difference in film thickness of a device formed on the wafer surface, which has been one factor that hinders the adoption of a processing method using fixed abrasive grains. To solve this problem, there has been proposed a thin plate deforming apparatus for deforming a chuck for fixing a wafer into an arbitrary shape in accordance with a difference in thickness of the wafer (for example, Japanese Patent Application Laid-Open No. 62-79647). Since it is used in an environment where sludge or sludge is generated, and because an actuator that deforms the chuck plate and its control circuit are built into the chuck that requires stable rotation, brushes etc. for energization are required. However, there have been problems such as fluctuation of rotation speed and fluctuation of the rotation shaft.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a thin plate deforming apparatus which solves the above-mentioned problem by enabling the deformation means to be removed by fixing and maintaining the deformation of the suction means by the fixing and maintaining means. It is.

[0006]

According to a first aspect of the present invention, there is provided a sheet deforming apparatus (23) for maintaining a state in which a thin plate (20) is deformed into an arbitrary surface shape.
Deformation means (22) for transforming 0) into an arbitrary surface shape;
Suction means (1) deformed according to the shape of the back surface of the deformed thin plate (20) and capable of adsorbing to the back surface, and fixing and maintaining means (21) for fixing and maintaining the suction means (1) at the deformed position. ), And after the deformation of the suction means (1) is fixed and maintained by the fixing and maintaining means (21), the deforming means (22) is removed from the surface of the thin plate (20). It is in the thin plate deformation device (23).

According to a second aspect of the present invention, the suction means (1) has a plurality of predetermined shapes formed by a concave groove (1c) having an upper surface capable of adsorbing to the rear surface of the thin plate (20) and having a lower surface. (For example, a triangular shape), and the thin plate (2) is formed by using the groove (1c) as a polygonal line.
A chuck plate (1) that can be elastically deformed according to the back surface shape of (0), wherein the fixed maintaining means (21) moves each of the elements (1d) in a predetermined movement direction and at any position. The thin plate deformation device (23) according to claim 1, characterized in that it is a support mechanism provided with a plurality of columns (3) that are fixedly supported on the plate.

According to a third aspect of the present invention, the deforming means (22) includes a plurality of correction front faces (18) abutting on the surface of the thin plate (20) at positions facing the plurality of columns (3).
The thin plate deformation device (23) according to claim 2, further comprising an up-and-down mechanism (18) having a) and moving the correction front surface (18a) in the predetermined moving direction.

According to a fourth aspect of the present invention, a reference surface (16) is provided on the deforming means (22) and the fixed maintaining means (21).
a, 19a), and the reference surface (16a, 19a)
Are the deforming means (22) and the fixed maintaining means (21)
The thin plate deforming device (23) according to any one of claims 1 to 3, wherein when attached, the thin plate deforming device (23) comes into contact with each other to regulate the inclination and the distance.

According to a fifth aspect of the present invention, the fixed maintaining means (21) is disposed on the main body (2) and the main body (2), and supports the plurality of columns (3) in the predetermined moving direction. Plunger (for example, 3a, 4, 5, 8, 7, 11)
A vacuum chamber (25) communicating with the upper surface of the chuck plate (1) and an external vacuum source; and a vertically moving member (14) vertically moved based on the pressure of the vacuum chamber (25). When the vacuum pressure is supplied by the vacuum source, the vertically moving member (14) moves the support (3) through the plunger (eg, 3a, 4, 5, 8, 7, 11) to the main body (3). The thin plate deformation device (23) according to any of claims 2 to 4, wherein the thin plate deformation device (23) is fixed to (2) and the upper surface of the chuck plate (1) sucks the rear surface of the thin plate (20). is there.

[Operation] The deforming means (22) of the thin plate deforming device (23) deforms the thin plate (20) into an arbitrary surface shape. Then, the suction means (1) is deformed in accordance with the shape of the back surface of the thin plate (20) and sucks in vacuum, and the support (3) of the fixing and maintaining means (21) is fixed based on the vacuum pressure. Maintain the deformation of 1). Thereafter, when the deforming means (22) is removed from the surface of the thin plate 20, the thin plate (2) is removed.
The surface of 0) is maintained in a shape deformed by the deforming means (22).

Note that the reference numerals in parentheses are for the purpose of comparison with the drawings, but are for the purpose of facilitating the understanding of the present invention. It has no effect.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments according to the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a thin plate deforming device 23 according to the present invention, FIG. 2 is a sectional view showing a deformation maintaining device 21 of the thin plate deforming device according to the present invention, and FIG.
FIG. 4 is a bottom view showing the chuck plate 1 mounted on the device 1, FIG. 4 is a partially enlarged sectional view showing a support mechanism of the deformation maintaining device 21, and FIG.
FIG. 2 is a sectional view showing a thin plate attaching device 22 of the thin plate deforming device according to the present invention. In this embodiment, the vertical direction and the horizontal direction mean the vertical direction and the horizontal direction in the sectional views shown in FIGS. 1, 2, 4, and 5, respectively. As shown in FIG. 1, the thin plate deforming device 23 according to the present invention includes a deformation maintaining device (fixing maintaining device) 21, a substantially disk-shaped chuck plate (sucking device) 1, and a wafer 20 in this order from below. And a thin plate mounting device (deformation means) 22.

As shown in FIG. 2, the deformation maintaining device 21
Has a chuck body (main body) 2 which can be mounted with the same diameter as the chuck plate 1, and is mounted so that the chuck plate 1 has a vacuum chamber 24. On the upper surface of the chuck plate 1, a pocket 1a for vacuum-sucking the back surface of the wafer 20 is provided.
The pocket 1a communicates with a vacuum chamber 24 on the lower surface of the chuck plate 1 through an air suction hole 1b. As shown in FIG. 3, the lower surface of the chuck plate 1 is
c, the element 1d is divided into a plurality of elements 1d having a predetermined shape (for example, a triangular shape). Each element 1d is configured to be elastically deformable by using the concave groove 1c as a polygonal line. It is attached. The chuck body 2 is provided with the chuck plate 1 in the vertical direction at a position near each apex of an element 1 d provided on the lower surface of the chuck plate 1.
Are provided, and a supporting mechanism is configured.

As shown in FIG. 4, the column 3 is held by a bush 4 fixed to the chuck body 2 in a state where there is almost no gap in the vertical direction and in the horizontal direction. The tip is in contact with the chuck plate 1. Also,
The lower rear end of the column 3 has a tapered hole 3a that opens downward, and the tapered hole 3a has a plurality of split grooves 3b radial from the center. By providing a plurality of claws 3c formed between them,
It is configured to easily spread radially outward by a force acting from the inside of the tapered hole 3a.

The support 3 has a plurality of balls 5 respectively corresponding to a plurality of claws 3c provided in the tapered hole 3a, and the support 3 is in a state where the support 3 is freely movable in the vertical direction (details will be described later). .) A ball guide 6 for maintaining the taper hole 3a and the ball 5 at the initial relative position, and a spring 7 for urging the ball 5 downward through the ball guide 6 to regulate the vertical position. ing. A ball retainer 8 is provided at the lower rear end of the column 3 to regulate the vertical initial relative position between the tapered hole 3a and the ball 5 and has a ball guide groove to prevent the ball 5 from being biased. The pin 9 fixed to the ball retainer 8 is
Into the groove 3b provided in the tapered hole 3a of
The rotation direction phase between the ball 5 and the ball retainer 8 is regulated, that is, the ball 5 and the claw 3c are regulated to have the same phase. Further, between the ball retainer 8 and the plate 10 fixed to the chuck body 2 in contact with the rear end of the column 3, a column pressure spring 11 is provided. The tip of 3 is the chuck plate 1
Is pressurized and pressurized. Above bush 4, tapered hole 3
a, ball 5, ball retainer 8, springs 7 and 1
1 and the like constitute a so-called plunger.

On the other hand, as shown in FIG. 2, a diaphragm 12 is provided below the chuck body 2 opposite to the upper side where the chuck plate 1 is mounted, to form a vacuum chamber 25. 13 by chuck body 2
Fixed to. The diaphragm 12 has a taper rod (vertical moving member) 14 for fixing the vertical position of the column 3 at a position corresponding to each column 3 and a piece 15.
Are fixed so as to sandwich the diaphragm 12.
The tip taper portion 14a of the taper rod 14 is
Is inserted further inside the plurality of balls 5 arranged inside the tapered hole 3a, and the ball 5 is in contact with the tapered hole 3a via the ball 5 with almost no gap (see FIG. 4).

The chuck body 2 is provided with a vent hole 2a for vacuum-sucking the wafer 20.
a is two vacuum chambers 24, 25 between the chuck plate 1 above and below the chuck body 2 and the diaphragm 12;
And the diaphragm 12 and the ring 13 are also opened at positions corresponding to the ventilation holes 2a, respectively, so that they can communicate with an external vacuum source (not shown). Further, the chuck body 2 has three reference pins 16 each having a reference surface 16a for regulating a relative inclination and a distance from the thin plate mounting device 22 so as to penetrate an outer peripheral portion of the chuck surface of the chuck plate 1. The above (for example, four) are provided (see FIG. 3).

Since the deformation maintaining device 21 according to the present invention has the above configuration, in the open state where the external vacuum source does not work, when the chuck plate 1 is pushed down, the chuck plate 1
Is also moved downward, and the tapered rod 14 is also pushed down via the ball 5. Since the tapered rod 14 is attached to the diaphragm 12 having low rigidity, the claw provided on the support 3 is provided. 3c moves downward together with the column 3 without exerting a reaction force enough to open it,
That is, it does not hinder the downward movement of the column 3. In addition, when the chuck plate 1 moves upward, the taper rod 14 moves upward together with the column 3 without opening the claw 3c. That is,
In this open state, the column 3 is freely moved in response to the force of the column pressure spring 11 that pressurizes and presses the column 3 against the vertical external force acting on the chuck plate 1. Deform to.

Next, the wafer 20 is placed above the chuck plate 1.
In a vacuum suction state in which an external vacuum source is operated with an external force, the external force based on the atmospheric pressure acting on the surface of the wafer 20 and the external force based on the atmospheric pressure acting on the lower surface of the diaphragm 12 support the chuck plate 1. 3, while being almost offset via the ball 5 and the tapered rod 14, the tip tapered portion 14 provided on the tapered rod 14 via the ball 5
Due to the wedge action of a and the tapered hole 3a of the column 3, the claw 3c provided in the tapered hole 3a of the column 3 spreads in the radial direction and is fixed to the bush 4 by friction. In this process, an external force due to the atmospheric pressure acting on the surface of the wafer 20 acts to slightly deform the chuck plate 1 downward. However, the external force is repelled by the column pressing spring 11 which pressurizes and presses the chuck plate 1. The deformation of the chuck plate 1 is prevented. Therefore, in this vacuum suction state, the chuck plate 1 is fixed while maintaining its shape.

It is also possible to increase the frictional fixing force of the column 3 by appropriately forcibly pressing the lower surface of the diaphragm 12, and by forcibly pressing before the external vacuum source is actuated, so that the wafer can be suctioned. It is also possible to fix the column 3 to the support.

Next, the thin plate mounting device 22 according to the present invention will be described.
Will be described with reference to the drawings. As shown in FIG. 5, the thin plate mounting device 22 is provided with a vertically movable mechanism 18 that can be arbitrarily moved up and down at positions facing the plurality of columns 3 of the deformation maintaining device 21 on the carrier body 17. The end face of the vertical mechanism 18 has a correction front surface 18a. The up-down mechanism 18 itself is composed of a piezo element or the like, and its control technique and the technique of measuring the thickness data of an insulating film or the like formed on the surface of a wafer are well-known techniques, and thus detailed description is omitted.

The thin plate mounting device 22 controls the control unit 2 based on the film thickness data of the wafer 20 at positions respectively opposed to the plurality of columns 3 of the deformation maintaining device 21 measured by an external measuring device.
Numeral 6 can control the correction front surface 18a formed on the end face of each of the up-and-down mechanisms 18 formed of a piezo element or the like to an arbitrary desired position. In addition, since the up-down mechanism 18 is provided at a position facing the column 3, the chuck plate 1 can be deformed or fixed with high accuracy when a wafer 20 described later in detail is attached.

The carrier body 17 is provided with a vent hole 17a for holding the wafer 20 by vacuum suction, so that the carrier body 17 can communicate with an external vacuum source (not shown). Further, the carrier body 17 has a reference surface 19a at a position corresponding to the reference pin 16 of the deformation maintaining device 21 for regulating the relative inclination and distance, similarly to the reference surface 16a of the reference pin 16. Reference pin 19 is provided.

The thin plate mounting device 22 has a wafer 20
A vertical mechanism 18 for deforming the surface shape of the wafer 20 into a desired shape is provided. However, if a constant surface shape of the wafer 20 is required, the vertical mechanism 18 may not be provided. 17 may be formed by directly forming a fixed correction front.

Hereinafter, the operation of attaching the wafer 20 by the deformation maintaining device 21 and the thin plate attaching device 22 will be described with reference to the drawings. First, as shown in FIG. 5, in order to obtain a desired wafer surface shape from the film thickness data measured in advance of the wafer 20, a correction front surface 18 formed on an end face of the vertical mechanism 18 is used.
In a state where a is controlled, the wafer 20 is sucked by an external vacuum source to be in a holding state. In this holding state, the surface of the wafer 20 comes into contact with the correction front surface 18a under the influence of the atmospheric pressure acting on the back surface of the wafer 20 and is corrected and deformed to a desired wafer surface shape to some extent. Therefore, it is not corrected and deformed to the target wafer surface shape.

The wafer 20 held by the thin plate mounting device 22
In the operation of attaching the wafer 20 to the deformation maintaining device 21 which is a chuck for processing and holding the wafer 20, the wafer 20 is moved to the respective reference pins 16 of the open deformation maintaining device 21 in which the external vacuum source is not working. The thin plate mounting device 22 is moved until the respective reference pins 19 of the held thin plate mounting device 22 contact each other. Since the moving means is not a special method, the description is omitted.

As shown in FIG. 1, when the reference pin 16 and the reference pin 19 are in contact with each other, the relative inclination of the deformation maintaining device 21 and the thin plate mounting device 22 is regulated as described above, The distance between the straightening surface 18a of the mounting device 22 and the chuck plate 1 of the deformation maintaining device 21 is regulated. The distance is equal to or less than the minimum thickness of the wafer 20, that is, the column pressing spring 11 provided on the column 3 supporting the chuck plate 1 is compressed by the thickness of the wafer 20, and the wafer 2 is compressed.
0 is adjusted to a distance at which pressurization and pressurization that can sufficiently correct the deformation are performed.

For this reason, the surface of the wafer 20 is corrected and deformed by the pressurizing pressure of the column pressing spring 11 so as to contact the correction front surface 18a of the thin plate mounting device 22, and the chuck plate 1 of the deformation maintaining device 21 Then, the wafer 20 is elastically deformed into a shape absorbing the thickness difference, and comes into contact with the back surface of the wafer 20. From this state, when an external vacuum source (not shown) joined to the deformation maintaining device 21 is operated to bring the vacuum plate into a vacuum suction state, the column supporting the chuck plate 1 as described above remains elastically deformed. 3 is fixed to the chuck body 2, and the wafer 20 is vacuum-sucked to the chuck plate 1 while maintaining the surface shape. Thereafter, when the external vacuum source connected to the thin plate mounting device 22 is stopped and the thin plate mounting device 22 is removed from the deformation maintaining device 21, the surface shape of the wafer 20 is corrected and deformed to a desired shape and maintained. Thus, it is possible to obtain the deformation maintaining device 21.

As described above, the deformation maintaining device 21 having a simple structure is not a conventional thin plate deforming device having a built-in actuator for deforming the chuck plate and its control circuit.
Thereby, the surface shape of the wafer 20 can be maintained and the surface can be processed. That is, it is possible to obtain an inexpensive thin plate deforming device 23 having a simple structure. In addition, the thin plate deformation device 2
Since the deformation maintaining device 21 of the third embodiment has a simple structure, high accuracy can be obtained and high reliability can be obtained even when used in an environment where grinding fluid or sludge is generated.

[0031]

According to the first aspect of the present invention, the deforming means deforms the thin plate into an arbitrary surface shape, the suction means deforms and adheres according to the back surface shape of the thin plate, and the fixing maintaining means deforms and adheres. After the fixing is maintained, the deforming means is removed from the surface of the thin plate, so that the surface shape of the thin plate is maintained by the suction means and the fixing maintaining means which are not provided with the conventional actuator for deforming the chuck plate and its control circuit. , The surface can be processed. That is, an inexpensive thin plate deforming device having a simple structure can be obtained. Further, since the suction means and the fixing and maintaining means have simple structures, high precision can be obtained and high reliability can be obtained even when used in an environment where a grinding fluid or sludge is generated.

According to the second aspect of the present invention, the suction means is a chuck plate that has an upper surface that is attracted to the back surface of the thin plate and that is elastically deformed in accordance with the shape of the back surface of the thin plate using a concave groove formed on the lower surface as a polygonal line. The fixing and maintaining means is a supporting mechanism that supports the chuck plate movably in the vertical direction and can be fixed at an arbitrary position, so that the chuck plate is attached to the back surface of the thin plate in a state where the chuck plate is attracted to the back surface of the thin plate. It is deformed following, and the support mechanism can fix the chuck plate at an arbitrary position.
Thus, the thin plate can be fixed while maintaining the surface shape.

According to the third aspect of the present invention, since the deforming means is provided with an up-down mechanism for vertically moving a plurality of correction fronts in contact with the surface of the thin plate at positions facing the plurality of columns, The surface shape of the thin plate can be made a desired shape based on, for example, film thickness data. Further, since the correction front face is provided at a position facing the support column of the supporting mechanism, the chuck plate can be deformed or fixed with high accuracy following the back surface of the thin plate.

According to the fourth aspect of the present invention, the deforming means and the fixing and maintaining means are provided with a reference surface, and when the deforming means and the fixing and maintaining means are mounted, the reference surfaces come into contact with each other and have an inclination and a distance. Therefore, while restricting the relative inclination of the deforming means and the fixing and maintaining means, the distance can be regulated, and the thin plate can be pressurized and pressurized so that the deformable deformation can be sufficiently performed.

According to the fifth aspect of the present invention, when the vacuum pressure is supplied by the vacuum source, the vertical moving member fixes the column to the main body via the plunger, and the upper surface of the chuck plate has the upper surface of the thin plate. Therefore, the fixing maintaining means can fix the deformation of the thin plate while adsorbing the thin plate with the vacuum pressure supplied by one vacuum source.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a thin plate deforming apparatus according to the present invention.

FIG. 2 is a sectional view showing a deformation maintaining device of the thin plate deformation device according to the present invention.

FIG. 3 is a bottom view showing a chuck plate mounted on the deformation maintaining device.

FIG. 4 is a partially enlarged cross-sectional view showing a column of the deformation maintaining device.

FIG. 5 is a sectional view showing a thin plate attaching device of the thin plate deforming device according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 suction means (chuck plate) 1c concave groove 1d element 2 main body (chuck body) 3 support 14 vertical moving member (taper rod) 16a reference surface 18 vertical mechanism 18a straightening surface 19a reference surface 20 thin plate (wafer) 21 fixed maintaining means (deformation) Maintenance device) 22 Deformation means (thin plate mounting device) 23 Thin plate deformation device 25 Vacuum chamber

Claims (5)

[Claims] 1. A thin plate deforming apparatus for maintaining a state in which a thin plate is deformed into an arbitrary surface shape, a deforming means for deforming the thin plate into an arbitrary surface shape, and deforming according to a back surface shape of the deformed thin plate. An adsorbing means that is freely adsorbable to the back surface; and a fixing maintaining means for fixing and maintaining the adsorbing means at its deformed position. After the deformation of the adsorbing means is fixed and maintained by the fixing and maintaining means, the deformation The thin plate deforming device, wherein the means is removed from the surface of the thin plate. 2. The suction means, wherein an upper surface is freely adsorbable on a rear surface of the thin plate, and is divided into a plurality of elements having a predetermined shape by a concave groove on a lower surface, and the concave groove is used as a polygonal line to form the thin plate. A chuck plate capable of elastically deforming in accordance with the shape of the back surface, wherein the fixed maintaining means includes a plurality of columns for supporting each of the elements so as to be movable in a predetermined moving direction and fixed at an arbitrary position. The thin plate deformation device according to claim 1, wherein the device is a support mechanism. 3. The deforming means has a plurality of correction fronts abutting on the surface of the thin plate at positions facing the plurality of columns, and includes a vertical mechanism for moving the correction fronts in the predetermined moving direction. The thin plate deformation device according to claim 2, characterized in that: 4. A reference surface is provided on the deforming means and the fixing and maintaining means, and the reference surface is in contact with each other when the deforming means and the fixing and maintaining means are attached to regulate the inclination and the distance. The thin plate deformation device according to any one of claims 1 to 3, characterized in that: 5. The fixing and maintaining means communicates with a main body, a plunger disposed on the main body and supporting the plurality of columns in the predetermined moving direction, and an upper surface of the chuck plate and an external vacuum source. A vacuum chamber; and a vertically moving member that moves vertically based on the pressure of the vacuum chamber. The vertically moving member fixes the support to the main body via the plunger by a vacuum pressure based on the vacuum source. The thin plate deformation apparatus according to any one of claims 2 to 4, wherein an upper surface of the chuck plate sucks a rear surface of the thin plate.