JPS6142421B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to semiconductor wafers (hereinafter referred to as wafers).
This invention relates to an improvement of a rotating holder for wafers for vacuum suction and rotation.

A conventional rotating holder consists of an integrally formed rotating body 1 as shown in FIG. 1, and its upper surface 1a is relatively wide and flat so as to stably hold a wafer 2, and its legs 1b are It has a thin cylindrical shape that makes it easy to rotate at high speeds. An air passage (IC) is provided in the center of the rotating body 1 along the rotation axis, and an air passage (IC) is provided in the leg 1b so as to drive the rotating body 1 and fit into a motor equipped with a vacuum source. A relatively large-diameter hole 1d is formed, and a countersunk-shaped hole 1e is formed in the upper surface 1a so that the wafer 2 can be easily attracted.

Now, the main use of this rotating body 1 is a photoresist coating process used in photolithography. That is, in the photoresist coating process, as shown in FIG.
The photoresist film is dropped onto the center of the rotating body 1, that is, on the central axis of the rotating body 1, and then rotated at 2000 to 4000 rpm to form a photoresist film with a uniform thickness on the surface of the wafer 2.

In this case, while the wafer 2 is being rotated, the rotating body 1 must maintain a vacuum in the air passage 1c, but the wafer 2 is generally about 100 to 300 μm thick; Wafers that are broken immediately after vacuum holding, during rotation, or broken due to malfunction are often held. Therefore, if photoresist is dropped in such a case, an accident may occur in which the photoresist gets into the air passage 1c. This accident actually results in a huge drop in productivity. The reason is that this air passage 1
Since c is kept in a vacuum, photoresist dropped by mistake will penetrate deep into the vacuum circuit and damage the sensor controlling the degree of vacuum and the vacuum source. Therefore, whenever such an accident occurs, the equipment must be disassembled and cleaned, which greatly reduces productivity.

This invention was made in order to eliminate the drawbacks of the conventional ones.By providing an air passage in the upper part of the rotating holder to avoid the center part, the photoresist can be maintained even if the wafer breaks. It is an object of the present invention to provide a rotating holder that prevents air from entering the passageway.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows an embodiment of the present invention. In the figure, a seating portion 3f is provided on the upper surface 3a of the rotating body 3, and a female thread 3h is machined on the inner peripheral surface of the seating portion 3f. has been done. Further, 3g is a plate-shaped body with both main surfaces flat, and a plurality of vacuum suction holes 3e each having a countersunk surface are provided at positions deviating from the central axis of the rotating body 3. ing. or,
On the outer peripheral surface of the plate-shaped body 3g, there is a female thread 3 of the seated part 3f.
A male screw 3i corresponding to h is machined, and this plate-shaped body 3g is screwed into the rotating body 3 and fixed. Furthermore, the thickness of this plate-shaped body 3g is shorter than the depth of the seated portion 3f, so that the air passage 3c and the vacuum suction hole 3e communicate with each other when the upper surface 3a is flat. It is designed so that it does not interfere with

In the rotating body 3 according to this embodiment, the vacuum suction hole 3e of the plate-shaped body 3g is provided at a position deviating from the central axis of the rotating body 3, so that even if the wafer 2 is cracked, the photoresist is directly exposed to the air. This reduces the number of accidents caused by people entering the passageway 3c. Also, air passage 3
Even if the photoresist enters into the area c, the air passage is inevitably long in this embodiment, so it is less likely to go deep into the device, and maintenance becomes easier. Therefore, usually only this rotating body 3 is removed and the plate-like body 3 is removed.
Just unscrew g and clean it with an organic solvent.

Now, in the above embodiment, by installing the packing 3j between the seating portion 3f and the plate-shaped body 3g, it is possible to improve the airtightness and further increase the vacuum suction force. Furthermore, if a groove is formed in the seated portion 3f to form a liquid reservoir 4 as shown in FIG. 3, most of the invading photoresist can be captured in the liquid reservoir 4. However, in this case, it is effective to form the liquid reservoir 4 directly below the vacuum suction hole 3e.

Note that aluminum, stainless steel, and the like are suitable as materials constituting the rotary holder of the present invention.

Further, in the above embodiment, the embodiment has been described with respect to a semiconductor wafer, but it is obvious that the present invention is not limited to this, and can also be used for a rotating holder for a wafer-shaped body made of glass, crystal, sapphire, or other materials.

As described above, the present invention provides a separate body in which a vacuum suction hole is provided in a seating portion bored on the upper surface of a rotating body having a T-shaped cross section at a position that avoids the air passage provided in the central axis of the rotating body. This has the effect of reducing accidents in which the photoresist damages the air passage of the rotating body and the inside of the mounting device during the photoresist coating process. Furthermore, if packing is installed at the bottom of the plate-shaped body, the vacuum density will be improved, and the accident of the wafer coming off during rotation will be reduced. Furthermore, by forming a liquid reservoir at the bottom of the vacuum suction hole, damage to the inside of the device can be further reduced.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional wafer rotating holder, and FIGS. 2 and 3 are sectional views showing an embodiment of the present invention. 3...Rotating holder, 3c...Air passage, 3a
...Top part, 3f... Seat part, 3g... Plate body, 3e... Vacuum suction hole, 3h... Female screw, 3i
... Male thread, 3j... Packing, 4... Groove.
Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. A rotating body having a T-shaped cross section, a seating portion formed by drilling the upper surface of the rotating body into a disk shape, and a seating portion provided at the center of the rotating body and having one end connected to the rotating body. An air passage that opens at the lower end surface of the leg of the body and the other end opens at the seated portion, and a male thread is formed on the outer circumferential surface in correspondence with the female thread formed on the inner circumferential surface of the seated portion. a plate-shaped body screwed into the seated part so that the upper surface of the rotating body is flat and the lower surface does not come into contact with the seated part, and a center part of the plate-shaped body 1. A wafer rotation holder, characterized in that the wafer is vacuum suction-held on the upper surface of the rotary body, the wafer being held by vacuum suction on the upper surface of the rotating body. . 2. The wafer rotation holder according to claim 1, wherein the seating portion has a groove formed in its bottom surface. 3. The wafer according to claim 1 or 2, characterized in that packing for improving vacuum density is interposed between the bottom surface of the seating portion and the lower surface of the plate-shaped body. rotating holder.