JP2000269310A - Semiconductor wafer support device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor wafer support device of a structure, wherein a semiconductor wafer can be uniformly and closely supported, there is no possibility of a fall-off or the like even at the time of transportation of the wafer, and there is not a possibility that electrostatic breakdown of the wafer or the like is generated at the ion implantation. SOLUTION: This semiconductor wafer support device is one constituted in such a structure that a semiconductor wafer 12 with a resist 13 coated on its upper surface is mounted on a back plate 11, and the outer peripheral part of the wafer 12 is fixed with clamps 15. The clamps 15 have a downward slant surface 17 and at the same time, are dividedly arranged in the direction of the outer periphery of the wafer 12. The wafer 12 is fixed in such a way that the outer peripheral ends of the wafer 12 are independently pressed by the slant surfaces 17 from the upper side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor wafer supporting apparatus for supporting, for example, a semiconductor wafer for carrying it.

[0002]

2. Description of the Related Art The prior art will be described with reference to FIGS. 4 is a schematic cross-sectional view, FIG. 5 is a plan view, FIG. 6 is a view for explaining a charging state at the time of ion implantation, and FIG. 7 is a view for explaining a surface potential without a clamp. FIG. 8 is a diagram for explaining the surface potential at the moment when breakdown occurs when there is a clamp.

In FIG. 4 to FIG. 8, reference numeral 1 denotes a back plate made of, for example, aluminum (Al), which is grounded, and 2 denotes a semiconductor wafer mounted on the upper surface of the back plate 1; 1.3μ on top of
The resist 3 is applied so as to have a thickness of about 1.5 μm to about 1.5 μm.
The periphery is cut at a width of 5 mm.

[0004] Reference numeral 4 denotes an upper fixing member opposed to the upper side of the back plate 1, and 5 is formed of aluminum suspended from the upper fixing member 4 by a clamp spring 6 and supported so as to be capable of moving up and down. The clamp 5 has four clamp pieces 7 protruding inward from the clamp 5. The clamp 5 is grounded via a clamp spring 6.

[0005] Then, in such a configuration,
Semiconductor wafer 2 placed on the upper surface of back plate 1
The upper part of the outer peripheral end of the resist 3 is pressed by the pressing piece 7 of the clamp 5 with a small force that does not damage the surface of the resist 3 by the urging force of the clamp spring 6, and is fixed on the back plate 1. Thus, the clamp 5
The semiconductor wafer 2 fixed and supported on the back plate 1 is transferred to, for example, an ion implantation apparatus (not shown), and is implanted with the resist 3 patterned into a predetermined shape as a mask.

[0006] However, in the above prior art,
Since the fixing of the semiconductor wafer 2 transferred to the ion implantation apparatus is performed by pressing the surface of the resist 3 with the clamp body 5, the semiconductor wafer 2 may be electrostatically damaged by the ion implantation. there were. That is, as shown in FIGS. 6 to 8, when the clamp 5 is not used, for example, the semiconductor wafer 2
Has a constant potential lower than the breakdown voltage.

[0007] However, since the surface of the resist 3 is pressed by the clamp 5, positive charges on the resist 3 are charged in the surface of the resist 3 and the clamp 5. A strong electric field is generated in the vicinity of the position where the pressing member 7 is pressed, and the breakdown voltage is exceeded in the vicinity of the pressing position of the holding piece 7 to cause electrostatic breakdown. In a region away from the pressing position of the presser piece 7, since the electric field is weak, the voltage does not exceed the breakdown voltage, and the breakdown does not occur.

For this reason, if the position where the pressing piece 7 of the clamp 5 presses is limited to the semiconductor wafer 2 only, the semiconductor wafer 2 usually has a rounded outer peripheral end due to beveling, and Since the peripheral cut width of the resist 3 is narrow, it is not possible to obtain a large allowance for pressing by the pressing piece 7. Further, the pressing force by the holding piece 7 cannot be increased because there is a possibility of damage or chipping, and the semiconductor wafer 2 moves when the semiconductor wafer 2 is moved together with the small holding allowance, so that the semiconductor wafer 2 comes off the holding piece 7. In some cases, they fall off.

In addition, when the semiconductor wafer 2 is pressed in an inclined state in which one pressing piece 7 is pressed earlier than the other because the pressing piece 7 is pressed and fixed by the annular clamp 5, the semiconductor wafer 2 is pressed first. The contacted portion strongly adheres to the back plate 1 and hardly adheres to the opposite side in the diameter direction, and the adhered state differs depending on the portion. In such a situation, the heat radiation through the back plate 1 is not evenly performed, the temperature of the semiconductor wafer 2 fluctuates in the plane, the outgassing of the resist 3 is poor, and the degree of vacuum of the apparatus is low. Problems such as lowering occur.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to fix and support a semiconductor wafer evenly in close contact with a back plate. The temperature distribution in the plane becomes uniform, the outgassing characteristics of the resist are improved, and there is no danger of falling off when the semiconductor wafer is transferred, and the situation such as electrostatic breakdown when performing ion implantation etc. It is an object of the present invention to provide a semiconductor wafer support device which does not cause the risk of occurrence.

[0011]

According to the present invention, there is provided a semiconductor wafer supporting apparatus comprising: a semiconductor wafer having a resist applied to an upper surface thereof mounted on a back plate; and an outer peripheral portion fixed by a clamp. In the apparatus, the clamp has a downward inclined surface, and the outer peripheral end of the semiconductor wafer is fixed by pressing the outer peripheral end from above by the inclined surface. It is characterized by being arranged in a plurality along the outer peripheral direction of the wafer,
Furthermore, the individual clamps are provided so as to be independently moved up and down and pressed.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIGS. 1 is a schematic cross-sectional view, FIG. 2 is a plan view, and FIG. 3 is a view showing a state where a semiconductor wafer is mounted with a center shift.

1 to 3, reference numeral 11 denotes a back plate made of aluminum (Al), which is grounded. Reference numeral 12 denotes a semiconductor wafer mounted on a flat upper surface of the back plate 11. The outer peripheral end of 12 is rounded by beveling. A resist 13 is applied on the upper surface of the semiconductor wafer 12 so as to have a thickness of about 1.3 μm to 1.5 μm, and an outer peripheral portion of the resist 13 is cut to a width of, for example, 1.5 mm ± 0.5 mm. I have.

An upper fixing member 14 is disposed above the back plate 11 so as to be opposed to the upper fixing member 14. The upper fixing member 14 has a plurality of, for example, four clamps 15 made of arc-shaped aluminum, each having a corresponding clamp spring. 16 and is supported by a guide (not shown) so as to be independently movable in the vertical direction. The arc-shaped clamp 15 is attached to the back plate 11.
A downwardly inclined surface having an arc length substantially equal to a length obtained by equally dividing the outer periphery of the semiconductor wafer 12 mounted thereon into four parts, and further expanding outward. 17
Is provided on the inner side.

Further, the inclination angle θ of the inclined surface 17 of the clamp 15 is appropriately determined by the curvature of the outer peripheral edge of the semiconductor wafer 12, the coating thickness of the resist 13, the peripheral cut width, and the like. The angle is set so as not to come into contact with the resist 13 when it comes into contact with the outer peripheral edge of the wafer 12. The clamps 15 are grounded.

With this configuration, the semiconductor wafer 12 placed on the upper surface of the back plate 11 is provided on the outer peripheral end of the rounded semiconductor wafer 12 with the inclined surfaces 17 of the individual clamps 15. And is pressed and fixed and supported by the urging force of the clamp spring 16 from above. At this time, the clamp 15 does not press the resist 13 and does not touch it. Therefore, the resist 13 is not damaged by the clamp 15. Further, even if the fixed and supported semiconductor wafer 12 is deviated from the center for some reason, the semiconductor wafer 12 is always pressed by the back plate 11 by the clamp 15 and is supported so as to be directed toward the center. It does not fall off the plate 11.

That is, as shown in FIG. 3, the clamp 1 presses the outer peripheral end of the semiconductor wafer 12 on the side shifted outward.
5 is pushed upward by the inclined surface 17 being pushed outward and compresses the clamp spring 16, and the interval H ₁ with the back plate 11 is increased. On the other hand, on the side shifted inward, the clamp 15 is pushed down by the extension of the clamp spring 16, and the distance H ₂ between the clamp 15 and the back plate 11 is reduced. This allows
The clamp 15 always presses the outer peripheral edge of the semiconductor wafer 12 without coming off and does not come into contact with the resist 13. As a result, the semiconductor wafer 12 is pressed downward and toward the center by the compression of the clamp spring 16 by the pressing of the inclined surface 17 of the clamp 15 which is urged with a larger urging force than the expanded one.

And, since it is configured as described above,
For example, even when the semiconductor wafer 12 supported on the back plate 11 is transferred to an ion implantation apparatus (not shown), and ions are implanted using the resist 13 patterned into a predetermined shape as a mask, some external force is applied during the transfer process. In addition, even if the semiconductor wafer 12 may be decentered on the back plate 11,
The outer peripheral edge is always pressed by the clamp 15 and does not fall off. Further, since the clamp 15 presses the outer peripheral edge of the semiconductor wafer 12 and does not contact the resist 13 on the upper surface, the distribution of the positive charges charged in the surface of the resist 13 at the time of ion implantation is uniform. And the semiconductor wafer 12 does not break down electrostatically.

Furthermore, since the semiconductor wafer 15 is independently pressed and fixed by the individual clamps 15, even in a situation where one clamp 15 is pressed in an inclined state to be pressed earlier than the other, The semiconductor wafer 12 is not pressed only by the clamp 15 that presses first, but is pressed by all the clamps 15, and the entire surface of the semiconductor wafer 12 is in close contact with the back plate 11. Thereby, the heat radiation through the back plate 11 is also performed uniformly, the temperature distribution of the semiconductor wafer 12 becomes uniform in the plane, and the outgassing of the resist 13 is also performed uniformly, so that the outgassing characteristics are improved. Thus, there is no fear that the degree of vacuum of the apparatus is reduced.

[0020]

As is apparent from the above description, according to the present invention, the semiconductor wafer is uniformly fixed and supported on the back plate, and the temperature distribution in the plane of the semiconductor wafer becomes uniform. The outgassing characteristics of the resist are also improved, so that there is no danger of falling off when transferring the semiconductor wafer, and there is no danger of causing electrostatic destruction and the like.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an embodiment of the present invention.

FIG. 2 is a plan view showing an embodiment of the present invention.

FIG. 3 is a diagram showing a state where a semiconductor wafer according to an embodiment of the present invention is placed with a center shift;

FIG. 4 is a schematic sectional view showing a conventional technique.

FIG. 5 is a plan view showing a conventional technique.

FIG. 6 is a view for explaining a charging state at the time of ion implantation in the related art.

FIG. 7 is a diagram for explaining a surface potential in the related art when there is no clamp.

FIG. 8 is a diagram for explaining a surface potential at the moment when breakdown occurs in a case where a clamp exists in the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Back plate 12 ... Semiconductor wafer 13 ... Resist 15 ... Clamp 16 ... Clamp spring 17 ... Inclined surface

Claims (3)

[Claims] 1. A semiconductor wafer supporting apparatus comprising: a semiconductor wafer having a resist applied to an upper surface thereof mounted on a back plate; and an outer peripheral portion fixed by a clamp, wherein the clamp has a downward inclined surface. ,
A semiconductor wafer support device, wherein an outer peripheral end of the semiconductor wafer is pressed from above by the inclined surface and fixed. 2. The semiconductor wafer supporting apparatus according to claim 1, wherein a plurality of clamps are arranged along an outer peripheral direction of the semiconductor wafer. 3. The semiconductor wafer supporting apparatus according to claim 1, wherein the individual clamps are provided so as to move up and down independently.