JPS621314B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coating apparatus, and more particularly to a double-sided coating apparatus for simultaneously and uniformly coating both sides of a wafer with photoresist.

In manufacturing semiconductor devices such as ICs (integrated circuits) and LSIs (large-scale integrated circuits), there is a process to partially form diffusion layers, wiring layers, insulating protective films, etc. on the surface of semiconductor thin plates (wafers). In each of these operations, it is necessary to apply a photoresist (photosensitive agent; hereinafter also simply referred to as resist) on the wafer surface in advance.

2. Description of the Related Art Conventionally, a resist coating apparatus having a structure shown in FIG. 2 has been known as an apparatus for coating a flat surface of a disk-shaped wafer 1 as shown in FIG. 1. In this device, a suction jig 4 is placed in the center of a processing chamber 3 covered by a cover 2. This suction jig 4 is fixed in communication with the upper end of a hollow shaft 8 rotatably attached to a bearing guide 6 of a support base 5 via a ball bearing 7. Further, a rotary joint 9 is connected to the lower end of the shaft 8, and this rotary joint 9 is connected to a vacuum source 11 via a pipe 10 or the like. Therefore, when the wafer 1 is placed on the suction surface, which is the upper surface of the suction jig 4, and the suction surface is evacuated, the wafer 1 is held in vacuum on the suction surface. On the other hand, at the bottom of the shaft 8 is a pulley 1 that is hung on an endless flat belt 12 that is rotated by a motor (not shown).
3 is installed. On the other hand, above the suction jig 4, a nozzle 15 for dropping the resist liquid 14 is arranged. Note that 16 is an exhaust section.

In such a conventional resist coating apparatus, the cover 2 is opened, the wafer 1 is placed on the suction jig 4, and then the cover 2 is closed. After that, wafer 1
While maintaining the wafer 1 in a vacuum, the motor is driven to rotate the wafer 1 at high speed, and the resist liquid 14 is dripped onto the wafer 1 from the nozzle 15. As a result, the resist liquid 14 is uniformly spread and applied over the entire upper surface of the wafer 1 due to centrifugal force.

By the way, as shown in FIG. 3, when forming the resist pattern 14a on both sides of the wafer 1, in the conventional apparatus described above, the resist liquid 14a is applied to one side of the wafer 1.
After coating the wafer 1, the vacuum operation of the suction jig 4 is released and the wafer 1 is taken out from the processing chamber 3.
After drying the resist liquid 14 applied to one side, the wafer 1 is turned over and placed on the suction surface of the suction jig 4 again, and the resist liquid 14 is applied to the other side of the wafer 1 again using the above procedure. Must be.

However, in this method, after the resist liquid 14 is applied to one side of the wafer 1, the wafer 1 is taken out from a clean processing chamber for drying and other operations, and then put back into the processing chamber, which often results in foreign matter adhering to the wafer surface. This results in a decrease in photoetching yield. Furthermore, since the wafer 1 is handled many times, external forces are applied to the wafer 1 many times, causing many problems such as the wafer 1 being more likely to crack.

Accordingly, an object of the present invention is to simultaneously apply a coating material to both sides of an object to be coated, thereby shortening the process length and reducing foreign matter on the back side of the object to be coated.

In order to achieve such an object, the present invention holds the outer circumferential end of the object to be coated with a V-groove chuck that presses down a constant pressure using a spring force, rotates it at high speed, and causes the V-groove chuck to generate pressure due to this rotation. Stable rotation is achieved by canceling centrifugal force using the flyball effect, and coating liquid is applied to both sides of the object by simultaneously supplying the coating liquid to both sides of the object. .

Hereinafter, the present invention will be explained in detail with reference to Examples.

4 to 6 are diagrams showing a resist double-sided coating apparatus according to an embodiment of the present invention, in which FIG. 4 is a front sectional view, FIG. 5 is an enlarged view showing a wafer support mechanism, and FIG. is also a side view.

As shown in FIG. 4, this device has a base 17 disposed on a support stand 5. A horizontally extending hollow rotating shaft 18 is attached to the base 17 through a bearing 19 so as to be rotatable therethrough. A flat pulley 21 on which a flat belt 12 for transmitting power from a motor 20 is hung is attached to one end of the rotating shaft 18, and the rotating shaft 18 is rotated at high speed by the drive of the motor 20. As shown in FIGS. 5 and 6, on the outer periphery of the other end of the rotating shaft 18, four levers 22, etc. are arranged at 90 degree intervals to form a support mechanism for supporting the wafer 1. . Each lever 22
extends along the axial direction of the rotating shaft 18, one left end projects from the end surface of the rotating shaft 18, and a V-groove chuck 24 having a V-groove 23 on the inner surface of the projecting end is fixed by a screw 25. ing. The centers of each V-groove 23 of the V-groove chuck 24 of each lever 22 are located on the same plane, and are adapted to bite into the peripheral edge of one wafer 1 when the lever 22 is closed. Further, each lever 22 is swingably attached to the rotating shaft 18 via a pin 26 at a central bent portion. Each lever 22 also has a compression spring 2 attached to the outer periphery of the rotating shaft 18.
7 so that it always closes. Further, a fly ball 28 is slidably inserted into the right end of the lever 22 at the other end and is fixed by a lock screw 29. This fly ball 28 serves to prevent the V-groove chuck 24 from moving away from the periphery of the wafer 1 and the wafer 1 from coming off the V-groove 23 due to the centrifugal force caused by the high-speed rotation of the rotating shaft 18. That is,
By adjusting the mounting position of the fly ball 28 whose mounting position is freely adjustable, the centrifugal force caused by the right end lever portion, the fly ball 28, etc., and the urging force by the compression spring are more effective than the centrifugal force caused by the wafer 1, the V-groove chuck 24, and the left end lever portion. By making it large, the wafer 1 can be held securely even under high speed rotation. Therefore, the fly ball 28 cancels the centrifugal force caused by the V-groove chuck 24 and the like.

On the other hand, a frame-shaped release plate 30 is disposed so as to surround the outside of each lever 22, and serves to open each lever 22 and release the clamp of the wafer 1 held in the V-groove chuck 24. This open plate 30 is moved parallel to the rotating shaft 18 so that the fourth
As shown in the figure, the rods 32 are attached to the tips of a plurality of rods 32 that slide on the base 17 via slide bearings 31. A collar 34 is attached to the middle of the rod 32, and one side of the collar 34 contacts the cam 33. A return spring 35 is disposed between the other side of the collar 34 and a part of the base 17, so that the collar 34 is always in contact with the cam 33. The movement follows the cam curve of the cam 33. Therefore,
By the rotation of the cam 33, the rod 32 is rotated to the rotation axis 1.
It reciprocates back and forth along the axial direction of the lever 8, and when it moves forward, it comes off the lever 22, and when it moves backward, it moves away from the lever 22.
Narrow down the raised right end part in the radial direction,
Expand the left end lever part in the radial direction. As a result, the V-groove chuck 24 releases the wafer 1 by the backward movement of the release plate 30 (the lever opens), and holds the wafer 1 by the forward movement (the lever closes).

On the other hand, the rotating shaft portion protruding from the left end of one end of the base 17 is covered by a cover 2 that can be opened and closed.
It is located inside the processing chamber 3. Further, the cover 2 is provided with an exhaust section 16 to forcibly exhaust the scattered resist. Also, the nozzle 3 at the tip penetrates through the cover 2.
6 facing approximately the center of the left side of the wafer 1 held in the V-groove chuck 24.
The wafer 1 is passed through the hollow part of the rotating shaft 18 and the nozzle 38 at the tip thereof is held in the V-groove chuck 24.
A resist supply mechanism is formed by a second resist solution supply pipe 39 facing approximately the center of the right side of the main pipe 41 and a main pipe 41 connecting the first and second resist solution supply pipes 37 and 39 to the pump 40. There is.

Next, a resist coating operation on both surfaces of a wafer using such an apparatus will be explained. First, after opening the cover 2, the cam 33 is operated to move the opening plate 30 backward, and the V-groove chuck 24 at the end of each lever 22 is opened. Thereafter, the wafer 1 is supplied to the holding position using a generally known wafer loader (not shown), and the cam 3
The release plate 30 is moved forward by the movement 3, and the restoring force of the compression spring 27 causes the four V-groove chucks 24 to hold the wafer 1. In this state, the wafer loader is removed from the processing chamber 3 and the cover 2 is closed.

Next, the rotating shaft 18 is rotated by the motor 20 via the flat belt 12, and the wafer 1 held in the V-groove chuck 24 is rotated. At this time, due to rotation, V
The centrifugal force generated in the groove chuck 24 acts in the opening direction of the V-groove chuck, but the centrifugal force is canceled by the fly ball 28 provided on the lever 22. Therefore, the wafer 1 is held at a constant pressure and will not come off. Then, the pump 40 pumps the nozzle 3.
6 and 38, the resist liquid 14 is simultaneously supplied onto the surface of the wafer 1 from both sides of the wafer 1, and the resist liquid 14 is uniformly applied to both sides of the wafer 1 at the same time.

According to such an embodiment, the work efficiency can be improved because the resist coating work for each side of the wafer 1 can be done by applying the resist solution once. Also,
The number of times wafer 1 is handled is reduced compared to before.
Moreover, since the pressure is maintained at a constant pressure by a compression spring, the incidence of cracking and chipping of the wafer 1 is also reduced. Furthermore, since the resist solution is coated on both sides of the wafer 1 once it is placed in the processing chamber, there is no need to take the wafer 1 out of the processing chamber 3 or dry it, unlike in conventional equipment. . Therefore, the probability that foreign matter will adhere to the surface of the wafer 1 is reduced, and the wafer 1 is less likely to be contaminated. Therefore, the maskability of the resist film formed by this apparatus is improved, and the manufacturing yield of diffusion layers, wiring layers, insulating protective films, etc. is increased. Also,
Reliability will also improve.

Further, according to this apparatus, since the wafer 1 is handled by chucking the periphery of the wafer 1, the wafer 1 is
The flat surface of the product is kept clean at all times, preventing contamination during chuck, which improves product yield. Furthermore, because of the peripheral edge support structure of the wafer 1, the structure of each part is simplified and the entire apparatus becomes compact.

Note that the present invention is not limited to the above embodiments. That is, the wafer support mechanism may have any other structure as long as it supports the wafer through the periphery of the wafer.

Further, the apparatus of the present invention may have a structure in which the wafer is supported in a horizontal state or the like and the resist liquid is applied to both surfaces of the wafer.

Furthermore, in the apparatus of the present invention, the object to be coated may be something other than a wafer, and the object to be coated may be something other than resist.

As described above, according to the double-sided coating apparatus of the present invention, it is possible to simultaneously and uniformly apply a coating material such as a resist to both surfaces of a plate-shaped object to be coated. Therefore, it is possible to shorten the coating process and reduce contamination of the object to be coated. Therefore, if applied to resist coating on wafers used in semiconductor manufacturing, it is possible to improve manufacturing yield and reduce manufacturing costs.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a wafer, FIG. 2 is a partially sectional front view of a conventional resist coating device, FIG. 3 is a front view of a wafer with resist coated on both sides, and FIG. 4 is a front view of a wafer coated with resist on both sides. FIG. 5 is an enlarged sectional view showing a part of FIG. 4, and FIG. 6 is a side view of FIG. 5. 1...Wafer, 14...Resist liquid, 18...
Rotating shaft, 22...Lever, 24...V groove chuck, 27...Compression spring, 28...Fly ball, 30...Release plate, 33...Cam, 36,3
8... Nozzle.

Claims (1)

[Claims] 1. A support mechanism that holds and rotates the object to be coated via the outer periphery of the object to be coated, and a coating material supply mechanism that sprays a coating material onto both surfaces of the object to be coated, and the support mechanism has a high-speed A rotating shaft consisting of a hollow shaft that rotates at A plurality of dogleg-shaped levers with a V-groove chuck attached to the inner side and a fly pole attached to the other end so that the attachment position can be adjusted freely;
A double-sided device characterized by comprising a spring that urges each lever in a direction in which each V-groove chuck holds the object to be coated in close proximity to each other, and an opening plate that opens each lever against this spring. Coating device.