JPS6214436A - Wafer chuck - Google Patents

Abstract

PURPOSE:To simplify the structure of a chuck, facilitate the entry and exit of wafers, and to easily establish insulation by a method wherein a lift mechanism is separated into a lifting member for the lifting of wafers and a driving means for the operation of the lift and the wafer chuck is equipped with an insulating board. CONSTITUTION:As for the structure of a wafer chuck of this design, a lifting member including a fork 5 in a base-side section A for the mounting and supporting of a wafer 1 is separated from a lift-driving means in the stage-side section for the elevating of the fork 5 relative to the base 3. The base 3 is attached to a member 3' with the intermediary of an insulating board 19 made of ceramics or the like. It follows that the chuck may be prevented from further complication in its internal structure because the base-side section is furnished only with the lifting member. Insulation is attained between the base and stage by using an insulating of a simple structure.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a wafer chuck for holding a semiconductor wafer for processing or inspection in a semiconductor manufacturing apparatus.

[Prior art] Manufacturing of various semiconductors such as aligners, coaters, blowers, etc.
At the t position, the semiconductor wafer is subjected to exposure, resist coating,
The wafer is held and fixed by a wafer chuck to perform operations such as blobbing, and after the operation is completed, it is released from the chuck and carried out. Therefore, it is desirable that the wafer chuck not only have a mechanism for simply holding the wafer, but also a mechanism that makes it easy to unload the wafer. Conventionally, four types of mechanisms for carrying out such wafers have been considered: a Bernoulli method, an air carrying-out method, a picking-up method, and a wafer lift method, and these are incorporated into wafer chucks.

The Bernoulli mechanism creates a negative pressure on the top surface of the wafer by blowing an airflow over the top of the wafer, making it easier to lift the wafer from the top of the chuck. It has the disadvantage that there is a risk of adhesion.

In the air unloading method, the wafer is similarly levitated by air, and then unloading air is blown onto the floating wafer using another air release device, and the wafer is taken out of the chuck by the force of the air. An additional drawback is that the wafer becomes unstable, requiring repositioning of the wafer when returning it to the wafer cassette.

The wafer gripping method does not have any of the above drawbacks because the evaporator is taken out mechanically without using fluid. However, in this method, there is a space on the wafer chuck for inserting the hand for loading and unloading the wafer on the underside of the wafer. Conventionally, in order to secure this space, a part of the top surface of the wafer chuck was cut out to form a recess for insertion of the hand. The method of forming this recess is that it is structurally in the cylinder, but it must be large enough to be used as a notch for inserting the hand, and when the wafer is placed on the wafer chuck and held. The flatness of the wafer may deteriorate due to the notch recess, and if a pressing force is applied to a portion of the wafer by a blower or the like, the presence of the notch recess may cause damage to the wafer.

The wafer lift type uses a lift built into the chuck to lift the wafer from the top of the chuck, thereby making it possible to insert the hand.The disadvantage of the presence of the notched recess is that the lift sinks on the chuck surface. This can be almost solved by making the wafers flush with each other, but with this conventional method, the entire lift mechanism is built into the wafer chuck, which not only makes the structure inside the chuck extremely complex, but also causes electrical noise during inspection. If the chuck needs to be electrically insulated independently to isolate the This resulted in interference.

[Object of the Invention] An object of the present invention is to provide a wafer chuck device equipped with a wafer lift type mechanism that facilitates loading and unloading of wafers without complicating the internal structure of the chuck. In addition, it is an object of the present invention to provide the above-mentioned wafer chuck having a structure in which electrical or thermal insulation of the chuck can be easily achieved with a simple structure.

[Structure of the Invention] In order to achieve the above-mentioned problems, in the wafer chuck of the present invention, the lift mechanism is separated into a lift member for lifting the wafer and a lift drive means for moving the same up and down, and the wafer chuck is mounted on the wafer as a chuck. The lift member is attached to a base, which is a section, and the lift drive means is attached to a stage side that supports the base. That is, the wafer chuck of the present invention includes the base, a lift member, a lift drive means, and an insulating member. The base constitutes the main part of the chuck having a flat surface for mounting the wafer on its upper surface, and is supported on the stage.

The lift member is mounted on the base so as to be movable between a raised position and a lowered position, and in the raised position lifts the wafer on the base away from the plane;
In the lowered position, it sinks down so that its upper surface level is substantially equal to or lower than the plane. Lift drive means is provided on a stage that supports a base, and moves the lift member between the open positions by displacement relative to the base. The lift drive means is spaced apart so as not to come into contact with the lift member when the lift member is in the lowered position. The insulating member is attached to the base side to which the lift means is attached in the attached state.

The lift driving means is electrically and/or thermally insulated from the stage side to which the lift driving means is attached.

In one embodiment 1'A of the invention, the lifting means includes a plurality of narrow forks for lifting the wafer from below, and the upper surface of the base has a plurality of preferably groove-like grooves for receiving the forks flush in the lowered position. A recess is provided.

In another embodiment of the invention, lifting means is attached to the base, and the base is supported by the stage via an insulating member.

Effects of the Invention In the wafer chuck of the present invention, as mentioned above, only the lift member, which is a driven part, is attached to the base side, so this lift member is arranged on the outer periphery of the base to make the internal structure of the chuck wm. Since the lift drive means on the stage side and the lift member on the base side are separated, insulation between them in the lift non-operation state is achieved by simply forming a gap, and in addition to this, the lift drive means on the stage side and the lift member on the base side are isolated. Insulation between the stage and the stage can be achieved by interposing a simple layer of insulating material.

[Example] Fig. 1 is a plan view showing an embodiment of the present invention, Fig. 2a is a sectional view of the main part when the lift member is in the lowered position, and Fig. 2b is a sectional view of the main part when the lift member is in the raised position. It is a diagram.

In the figure, the wafer chuck according to the present invention has a wafer 1
It can be considered to be divided into a base side part A for placing and holding the same, and a stage side part B as its supporting part, and the lift member including the fork 5 on the base side part A and the fork 5 on the stage side part. Lift driving means for raising and lowering the base 3 relative to the base 3 are arranged separately from each other.

In the base side portion A, the base 3, which is the main part of the chuck, has a built-in chucking mechanism (not shown), and also has a flat surface 2 on its upper surface on which the wafer 1 is placed, arranged at equal angular intervals of 120 degrees when viewed from the top. Three narrow groove-like recesses 4 extending in the radial direction from the outer peripheral edge to the center are provided on this plane 2. Forks 5 are pivotally supported at the ends of the recesses 4 of the base 3 so as to be movable up and down. This fork 5 is
a thin rod-shaped part 6 that fits exactly in the recess 4 of the base 3 and has an upper surface part that is lower than the base surface in the lowered position and supports the lower surface of the wafer 1 in the raised position;
A shaft portion 7 pivotally supported by the base 3 and a spring 9 that biases the shaft portion 7 downward so that the bar-shaped portion 6 is normally maintained in the lowered position.
and a convex portion 8 that serves as a position guide with respect to the periphery of the wafer 1, and constitutes the aforementioned lift member. This fork 5 can take a raised position by pushing up the lower end of its shaft portion 7 against the spring 9, and can take a lowered position by the spring force of the spring 9 by releasing this pushing up.

The lift driving means of the stage side portion B is responsible for raising and lowering the fork 5, and this will be explained below.

That is, the member 3' supported by a support mechanism (not shown) on the stage 12 supports the base 3 via the insulating plate 19, and also pivotally supports the push-up pin 10 opposite to the lower part of the shaft portion 7 of the fork 5. This push-up bottle 10 is normally urged downward by a spring 18, and when the fork 5 is in the lowered position, a gap is formed between the lower end of the shaft portion 7 and the upper end of the bottle 10, so that they separate from each other. It's like that. A bearing 11 is attached to the lower end of the push-up bottle 10, and this bearing 11 is attached to a helicoid ring 14.
It is in contact with the top surface of the surface with a low coefficient of friction. helicoid ring 1
Stage 4 has spiral protrusions 14a distributed in the same color at 120 degrees on the outer circumferential surface and internal gears 14b on the inner circumferential surface.
It is rotatably supported by a v-roller 13 bearing at 2. The internal gear 14b of the helicoid ring 14 meshes with the drive gear 16 via an intermediate gear 17 attached to the stage 12, and the drive gear 16 is rotated in the forward and reverse directions by the motor 15, thereby rotating the helicoid ring 14 in the forward and reverse directions. . Due to the relationship between the V roller 13 and the spiral protrusion 14a, the helicoid link 14 rotates with upward or downward parallel movement depending on its rotation direction. The upward and downward movements caused by the rotation of the helicoid ring are transmitted to the push-up pin 10 via the bearing 11, and as the push-up pin 10 rises, its upper end comes into contact with the shaft portion 7 of the fork 5, further pushing it against the spring 9. The wafer 1 is lifted up by the fork 5 as shown in FIG. 2b. A hand device (not shown) is inserted between the wafer 1 lifted up in this manner and the upper surface 2 of the base, and the wafer is carried in or out.

When the wafer 1 is placed on the base 3, that is, when the fork 5 is in the lowered position, the shaft portion 7 of the fork 5 and the push-up bin 10 are separated through a gap,
Furthermore, since the base 3 is attached to the member 3- via an insulating plate (ceramic or the like) 19, the base side is electrically and thermally insulated from the stage side. In this case, it should be noted that since the lift mechanism is separated into a two-part valve, it does not interfere with insulation, and the base can be isolated from the stage side by simply interposing the insulating plate 19.

In the above embodiment, the fork 5 was pushed up against the fixed base via the push-up pin 10 by the helicoid ring, but it is also possible to use another cam mechanism instead of the helicoid ring.

In addition, when the base 3 side is movable up and down, the push-up bin 10 is fixedly arranged on the stage side, and when the base is lowered, the fork 5 is prevented from descending by colliding with the push-up bin, so that the upper surface of the base when lowering is prevented. The fork 5 may be lifted relatively to the fork. In this case, there is an advantage that the elevating mechanism of the base can be used in common as the elevating mechanism of the base without providing a separate driving portion for elevating the fork. 3 and 48 and 4b.

In FIGS. 3, 4a and 4b, the same reference numerals are given to the parts having the same effect as in the above embodiment, and 20 is the push-up bottle 10.
This is a member that fixes the stage 12 to the stage 12.

When the base 3 is lowered by means (not shown) when loading and unloading wafers, the lower end of the shaft portion 7 of the fork 5 collides with the upper end of the fixed push-up bin 10, and as shown in FIG. The fork 5 lifts the wafer 1.

Since this method allows the fork to be raised and lowered without an external drive source, it is possible to simplify the mechanism for devices that have a mechanism for moving the base up and down, such as a wafer blobber.

In this example, the fixing member 20 of the push-up bottle 10 is arranged in three places, but instead of the push-up bottle 10, a push-up ring 10' arranged around the entire circumference is installed around the base as shown in Fig. 5. However, if the lower end of the shaft portion 7 of the fork 5 is made to be able to collide with the upper edge of this push-up ring 10', the wafer can be lifted by the fork 5 by lowering the base 3 in any rotational position. becomes possible.

[Effects of the Invention] As described above, according to the present invention, the wafer lift mechanism is divided into two parts, so the lift drive source can be provided outside the chuck, or the lifting mechanism of the chuck itself can be used as the lift drive source. There is an advantage that the chuck can be used in common, and therefore, it is only necessary to incorporate the lift driven part into the base side of the chuck, so that the internal structure of the chuck can be avoided from becoming complicated.

In addition, since it is possible to separate the two parts of the lift mechanism when the lift is not in operation, electrical or thermal insulation of the chuck base can be achieved by simply interposing an insulating layer.
The lift mechanism does not interfere with insulation. Furthermore, the wafer placement surface of the chuck is only provided with a narrow groove-like recess, and the fork fits flush with the recess, ensuring a completely flat wafer placement surface, which prevents deterioration of wafer flatness. There is no fear of damage to the wafer due to local external forces.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an embodiment of the present invention, FIG. 2a is a cross-sectional view of the main part when the lift member is in the lowered position, FIG. 2b is a cross-sectional view of the main part when the lift member is in the raised position, and FIG. FIG. 3 is a plan view showing another embodiment of the present invention, FIGS. 48 and 4b are sectional views of the main parts when the lift member is in the lowered position and the raised position, and FIG. 5 is a plan view showing another embodiment of the present invention. It is a top view which shows yet another Example. 1: Wafer, 2: Wafer mounting plane, 3: Base, 4: Groove-shaped recess, 5: Fork, 7: Shaft,
10: Push-up bottle, 11: Bearing, 12: Stage, 13: V roller, 14: Helicoid ring, 15: Motor, 16: Drive gear, 17: Intermediate gear, 19: Insulating plate.

Claims (1)

[Claims] 1. A base having a flat surface for placing a wafer on its upper surface; when the base is in a raised position with respect to the base, the wafer placed on the base is lifted away from the flat surface, and the wafer is moved to a lowered position. a lift member that is vertically movably supported by the base so that its upper surface level is substantially equal to or lower than the plane; a lift drive means for moving said lift member between said raised position and said lowered position by displacement and is spaced from said lift member when said lift member is in said lowered position; said base and said lift member; A wafer chuck characterized by comprising an insulating member that insulates between a stage and a lift drive means. 2. The lift member includes a plurality of forks that lift the wafer from below, and a plurality of recesses are provided on the upper surface of the base to receive the forks flush in the lowered position. Wafer chuck as described. 3. The wafer chuck according to claim 1, wherein a lift means is attached to the base, and the base is supported by the stage via the insulating member.