JPH06216018A - Coating device - Google Patents

Abstract

PURPOSE:To prevent the cleaning liquid intruding between a rotary holding means and the material to be treated. CONSTITUTION:In the coating device with which the material W to be treated, which is held by a rotary holding means 50, is coated with a treatment solution 58 while it is being rotated and the back side cleaning is performed by a cleaning liquid 68, a cleaning liquid intrusion preventing stepped part 78 is formed in the direction along the circumference of the cleaning liquid intrusion preventing part 78. As a result, a cleaning liquid intrusion preventing gap 80 is formed between the preventing stepped part and the back side of the material to be treated when the material to be treated is mounted, and the intrusion of the cleaning water into the gap when the cleaning operation is conducted can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating device.

[0002]

2. Description of the Related Art Generally, a resist coating apparatus as shown in FIG. 8, for example, is known as a coating apparatus for rotating an object to be processed such as a semiconductor wafer and applying a processing solution such as a photoresist solution to the object. . This coating apparatus includes a spin chuck 2 that is a rotation holding unit that horizontally holds and holds an object to be processed, for example, a semiconductor wafer W, and a resist liquid supply that drops a resist liquid as a processing liquid on the center of the surface of the wafer W. It has a nozzle 4 and an outer container 6 and an inner container 8 which are provided to surround the wafer W on the spin chuck 2 and to collect the resist liquid and the cleaning liquid scattered outward.

Then, during spin coating of the treatment liquid,
The scattered resist solution circulates to the back surface of the wafer due to the air flow generated by the rotation, and this adheres to the peripheral portion of the back surface of the wafer and causes particles in the subsequent steps. Therefore, below the spin chuck 2,
A back surface cleaning nozzle 10 that discharges a cleaning liquid for cleaning the resist liquid adhering to the back surface of the wafer W is provided, and after the resist liquid is applied, the back surface cleaning is performed using a highly volatile cleaning liquid (solvent) such as thinner. Is supposed to do.

[0004]

By the way, when performing the above-mentioned back surface cleaning, in order to completely remove the resist adhering to the back surface of the wafer, the direction of discharge of the cleaning liquid from the cleaning nozzle 10 is made variable, and the cleaning liquid 12 is chucked. It is also discharged toward the back surface of the wafer slightly outside the peripheral portion of the wafer, so that the back surface of the wafer as close as possible to the chuck is cleaned. However, when the back surface of the wafer close to the chuck 2 is also cleaned in this way, the scattered cleaning liquid 12 penetrates between the back surface of the wafer and the chuck 2 due to, for example, a capillary phenomenon as shown by an arrow 14, and the center of the back surface of the wafer and This will wet the surface of the chuck 2.

When the surface of the chuck 2 gets wet with the cleaning liquid as described above, the temperature of the chuck itself lowers due to the heat of vaporization of the highly volatile cleaning liquid, especially because it rotates at a high speed, and the next unprocessed wafer in this state. There was an improvement in that the temperature profile of the wafer itself was deteriorated when the wafer was sucked and held by the chuck 2, and as a result, the in-plane uniformity of the film thickness of the resist film coated on the wafer surface was impaired. For example, if the profile of the wafer temperature is deteriorated by using a normal resist solution, there is an improvement point that the thickness of the resist film becomes thinner in a portion where the wafer temperature is lower than in a portion where the wafer temperature is high. In particular, when a water-soluble polymer or gelatin whose viscosity changes sensitively with temperature is used as the resist solution, the in-plane uniformity of the film thickness of the resist film is further impaired.

Further, as described above, when the surface of the chuck 2 gets wet with the cleaning liquid, particles tend to adhere to this portion, and the yield also decreases due to the particles. The present invention has been made to pay attention to the above problems and to solve them effectively. An object of the present invention is to provide a coating device capable of preventing the cleaning liquid from entering between the rotation holding means and the object to be processed.

[0007]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention applies a treatment liquid while rotating an object to be treated which is held by a rotation holding means having a flat upper surface, In a coating device configured to clean the processing liquid adhering to the back surface of the object to be processed with a cleaning liquid discharged from a cleaning liquid discharge nozzle, the object to be processed is provided on a peripheral portion of an upper surface of the rotation holding means. A cleaning liquid intrusion prevention step portion is formed to form a cleaning liquid intrusion prevention gap for preventing the cleaning liquid from invading when placed and held.

[0008]

Since the present invention is constructed as described above, when the object to be treated is adsorbed and held on the upper surface of the rotation holding means, the cleaning water intrusion prevention step portion is formed on the peripheral portion of the upper surface of the holding means. Therefore, a cleaning liquid intrusion prevention gap is formed between this and the back surface of the object to be processed. Therefore, when cleaning the processing liquid adhering to the back surface of the object to be processed with the cleaning liquid discharged from the cleaning liquid discharge nozzle, the cleaning liquid accumulates in the vicinity of the entrance of the above-mentioned blocking gap, and this exerts the function of a plug, and the cleaning liquid is further inside. Can be prevented from entering.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the coating apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. 1 is a sectional view showing an embodiment of a coating apparatus according to the present invention, FIG. 2 is a plan view showing a processing mechanism equipped with the coating apparatus of the present invention, and FIG. 3 shows a rotation holding means of the coating apparatus of the present invention. FIG. 4 is a sectional view, FIG. 4 is a plan view showing the rotation holding means of the coating apparatus of the present invention, and FIG. 5 is a partially enlarged view showing the rotation holding means shown in FIG. In this embodiment, the case where the coating apparatus is applied to a resist coating apparatus that coats a resist on a target object will be described. The same parts as those of the conventional device are designated by the same reference numerals.

The processing mechanism 18 in which various processing devices such as a resist coating device are incorporated as shown in FIG. 2 will be described. The processing mechanism 18 is an object to be processed, for example, a semiconductor wafer W (hereinafter, simply referred to as a wafer). A processing apparatus unit 20 in which processing apparatuses for performing various processes are disposed, and a loading / unloading mechanism 22 for automatically loading / unloading the wafer W into / from the processing apparatus unit 20. . The carry-in / carry-out mechanism 22 has a wafer carrier 24 for storing the unprocessed wafer W, a wafer carrier 26 for storing the processed wafer W, an arm 28 for sucking and holding the wafer W, and the arm 28 for X ( An alignment stage 32 for aligning the wafer W and transferring the wafer W between the processing mechanism unit 20 and a moving mechanism 30 for moving in the left and right, Y (front and back), Z (vertical) and θ (rotation) directions. It has and.

The processing unit 20 is provided with a transport mechanism 36 which is movable along a transport path 34 formed in the X direction from the alignment stage 32. The transfer mechanism 36 is provided with a main arm 38 that is movable in the X, Y, Z, and θ directions. On one side of the transfer path 34, an adhesion processing device 40 that performs an adhesion process for improving the adhesion between the wafer W and the resist liquid film, and a solvent remaining in the resist applied to the wafer W are heated and evaporated. A pre-baking device 42 for performing the heating and a cooling device 44 for cooling the heat-treated wafer W are provided. On the other side of the transfer path 34, the wafer W
Coating device 4 according to the present invention for coating the resist liquid on the surface of
6 and a surface coating layer coating device 48 for coating and forming a CEL film or the like on the resist of the wafer W in order to prevent diffused light reflection during the exposure process.

The coating apparatus 46 according to the present invention holds a wafer W as an object to be processed on the upper surface thereof, for example, a spin chuck 50 which is a rotation holding means for rotating by holding it by vacuum suction, and the spin chuck 50. It has a spin motor 52 for rotating. The spin chuck 50 is formed in a flat plate shape and has a flat upper surface, and a plurality of holding vacuum holes (not shown) connected to a vacuum pump or the like are provided in the center thereof.

A bottom plate 56 is provided below the spin chuck 50 so that the rotary shaft 54 of the spin chuck 50 is inserted therethrough. Above the bottom plate 56, a processing liquid such as a resist supplied to the upper portion of the wafer W is provided. A container 60 is formed to prevent the liquid 58 from splashing. Specifically, the container 60 covers the outer periphery of the spin chuck 50 and has an annular outer container 60A whose upper end is slightly higher than the horizontal level of the spin chuck, and a lower part of the spin chuck. It is mainly configured by an annular inner container 60B extending in the outer peripheral direction. Both outer containers 6
The 0A and the inner container 60B are formed so as to be gradually inclined downward toward the outer side in the radial direction of the spin chuck, and are configured to guide the resist liquid adhering to these wall surfaces toward the bottom plate 56.

Further, the bottom plate 56 is formed so as to be gently inclined in one direction, and the container 60 is formed at the uppermost position.
An exhaust pipe 62 for exhausting the inside is connected, and a drain pipe 64 for discharging the resist liquid flowing down in the container, a cleaning liquid described later, and the like is connected at the lowest position. Further, on the bottom plate 56 slightly inward in the radial direction of the peripheral portion of the inner container 60B, a partition wall 66 is provided so as to stand up in an annular shape so as to prevent the drainage and the like from entering the inside.

Below the spin chuck 50, a cleaning liquid 68 such as thinner is applied toward the back surface of the wafer.
A plurality of cleaning liquid discharge nozzles 70 for discharging the cleaning liquid, for example, two cleaning liquid discharge nozzles 70 are provided. Specifically, these discharge nozzles 70 are arranged point-symmetrically with respect to the rotation center of the spin chuck, so that the back surface can be effectively cleaned even for a wafer having a large radius such as an 8-inch wafer. It is configured. The inclination angle θ of each discharge nozzle 70 with respect to the vertical direction may be set to, for example, about 45 °, or may be set within the range of 25 to 65 °, for example, in relation to the rotation speed with the spin chuck.

Each of the discharge nozzles 70 is connected to a cleaning liquid supply unit 74 having a cleaning liquid tank, a supply pump and the like via a pipe 72 and the like. In addition, the cleaning liquid supply unit 74 has a control means 76 including, for example, a microprocessor in which a cleaning process is programmed in advance.
The control means 76 also controls the number of rotations of the spin motor 52.
Here, when the cleaning liquid 68 made of, for example, thinner is released to remove the resist liquid adhering to the back surface of the wafer, the cleaning liquid 68 enters between the upper surface of the spin chuck 50 and the lower surface of the wafer W. It will wet the surface of the lever. Therefore, in order to prevent this, in the peripheral portion of the upper surface of the spin chuck 50 whose upper surface is flat,
The cleaning liquid intrusion prevention stepped portion 78 that is cut out in a stepped shape is formed in an annular or donut shape along the circumferential direction of the chuck 50.

In this case, the width L1 and the height H1 of the blocking step 78 depend on the size of the wafer W, but in the case of a 6 inch wafer, for example, about 5 mm and 0.2, respectively.
Set to about 0.5 mm. In this case, the diameter R1 of the chuck is, for example, 80 mm, while the diameter R2 between the step portions is set to 70 mm, but it is not limited to these numerical values. Then, the wafer W is attached to the spin chuck 50 having the blocking step 78 formed as described above.
Is held by suction, a cleaning liquid intrusion prevention gap for preventing the cleaning liquid 68 from entering between the back surface of the wafer and the upper surface of the chuck during cleaning between the blocking step portion 78 and the peripheral portion of the back surface of the wafer. 80 can be formed. In addition, above the spin chuck 50, the wafer W
A resist liquid supply nozzle 82 for supplying a processing liquid, for example, a resist liquid 58, is provided in the upper center.

Next, the operation of this embodiment configured as described above will be described. First, the unprocessed wafer W is unloaded from the wafer carrier 24 by the arm 28 of the loading / unloading mechanism 22 and placed on the alignment stage 32. Next, the wafer W on the alignment stage 32 is held by the main arm 38 of the transfer mechanism 36,
Each of the processing devices 40 to 48 is sequentially conveyed and processed.
Then, the processed wafer W is returned to the alignment stage 32 by the main arm 38, further carried by the arm 28, and stored in the wafer carrier 26.

In the resist coating apparatus 16 according to the present invention among the above processing apparatuses, the resist film forming operation is performed as follows. First, the wafer W is placed on the spin chuck 50, and this is suction-held by vacuum suction. Then, by driving the spin motor 52 while holding the wafer W, the spin chuck 50 and the wafer W adsorbed to the spin chuck 50 are rotated at a high speed, for example, at a rotation speed of 2000 rpm, and at the same time, a predetermined amount is supplied from the resist solution supply nozzle 82. Resist solution 58 is dropped and supplied onto the wafer W. At this time, the atmosphere in the container 60 is exhausted with a predetermined suction force via the exhaust pipe 62.

The supplied resist solution is used to rotate the wafer W.
Is applied to the wafer surface while being uniformly spread in the radial direction from the center of the wafer by the centrifugal force, and the surplus is scattered outward from the peripheral portion of the wafer by shaking off by the high speed rotation, and the inner wall surface of the outer container 60A. And inner container 60B
And the mist-like resist liquid adheres to the side surface and the back surface of the wafer W. If left as it is, it may cause particles. When the coating process for a predetermined time is completed in this way, the control means 76 drives the cleaning liquid supply part 74 to discharge the cleaning liquid 68 such as thinner from both cleaning liquid discharge nozzles 70 to clean the back surface of the wafer W and the side rinse. (Dissolving and removing the resist on the peripheral portion of the wafer W) is performed to remove the coating liquid adhering thereto.

When performing the back surface cleaning, the spin motor 58 is controlled by the control means 76 while the cleaning liquid 68 is being discharged, and the rotation speed of the wafer 2 is, for example, 500 to 2000 rpm.
By increasing or decreasing within the range of, the centrifugal force applied to the cleaning liquid that collides with the back surface of the wafer 2 and gradually increases, the scattered cleaning liquid reaches the inner wall surface of the outer container 64A and the outer wall surface of the inner container, These surfaces will be washed.

In cleaning the back surface of the wafer, for example, by changing the inclination angle θ of the discharge nozzle 70, the back surface of the wafer that is as close as possible to the peripheral surface of the chuck 50 is cleaned. Even so, the scattered cleaning liquid 68 tends toward the rotation center of the wafer and tends to infiltrate between the back surface of the wafer and the upper surface of the chuck. However, as shown in FIG. 6, in the present embodiment, since the blocking step 78 is provided on the peripheral edge of the upper surface of the spin chuck 50, when the wafer W is suction-held on the chuck upper surface, the blocking step 78 is formed. A cleaning liquid blocking gap 80 is formed between 78 and the back surface of the wafer. Therefore, the cleaning liquid scattered in the direction of the rotation center of the wafer is trapped by the action of the surface tension, the adhesive force and the like at the opening 80A of the blocking gap 80 and forms the liquid pool 84 there. It is possible to prevent the cleaning liquid from entering the blocking gap 80. That is, when the liquid pool 84 is formed at the opening end of the blocking gap 80, air is trapped inside the gap, and the trapped air pressure prevents further infiltration of the cleaning liquid.

Since the infiltration of the cleaning liquid is thus prevented, the chuck front surface and the wafer back surface are not wetted by the cleaning liquid containing particles. Therefore, in the conventional apparatus, since the chuck surface was wet with the volatile cleaning liquid, the temperature of the chuck itself was partially lowered by the heat of vaporization of the cleaning liquid. Since the chuck surface is never wet with the cleaning liquid, the temperature profile of the chuck surface is appropriately maintained without lowering the temperature. Therefore, even when the next unprocessed wafer is placed and held on this chuck, the temperature profile of the wafer is properly maintained, and even if the resist solution is sensitive to temperature, it is evenly distributed. By coating on the wafer surface, the in-plane uniformity of the resist film can be significantly improved. Further, as described above, since the chuck surface and the wafer back surface are not wetted by the cleaning liquid containing particles,
Residual particles can be reduced, and a decrease in yield due to this can be prevented.

Although the diameter R1 of the chuck 50 is set to 80 mm in the above embodiment, it is not limited to this.
For example, as shown in FIG. 7, the diameter R1 of the chuck 50 is set as large as possible within a range that does not prevent the rear surface of the wafer from being gripped by a handling arm (not shown).
The width L1 of the blocking step portion 78 may be set to be about 20 mm and set to be as long as about 20 mm. By setting the width of the blocking step portion 78 to be long in this way, it is of course possible to obtain the same effects as those shown in the previous embodiment, and the wafer is increased by the width of the blocking step portion 78. Since the back surface of W can be covered, it is possible to prevent the temperature change from occurring in the peripheral portion of the wafer W corresponding to this portion, and it is possible to further improve the in-plane uniformity of the film thickness of the resist film.

In the present invention, the case where a semiconductor wafer is used as the object to be processed has been described, but the present invention is not limited to this, and can be applied to, for example, a printed circuit board, an LCD substrate, a CD, and the like. The invention is not limited to a resist coating apparatus, but a developing solution coating apparatus, an etching solution coating apparatus,
It can also be applied to a magnetic liquid coating device, a cleaning device, and the like.

[0026]

As described above, according to the coating apparatus of the present invention, the following excellent operational effects can be exhibited. Since the cleaning liquid intrusion prevention step is formed to prevent the cleaning liquid from entering between the object to be processed and the rotation holding means, the holding means is not cooled by the heat of vaporization of the cleaning liquid, It does not adversely affect the temperature profile of the object to be placed. Therefore, the in-plane uniformity of the film thickness of the applied processing liquid can be significantly improved. Further, the surface of the holding means is not coated with the cleaning liquid containing particles, so that it is possible to suppress the decrease in yield due to the remaining particles.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a coating apparatus according to the present invention.

FIG. 2 is a plan view showing a processing mechanism equipped with the coating apparatus of the present invention.

FIG. 3 is a sectional view showing a rotation holding means of the coating apparatus of the present invention.

FIG. 4 is a plan view showing a rotation holding means of the coating apparatus of the present invention.

FIG. 5 is an enlarged view showing a rotation holding unit shown in FIG.

FIG. 6 is an operation explanatory view for explaining the operation of the coating apparatus of the present invention.

FIG. 7 is an enlarged view showing a main part of a modified example of the coating apparatus of the present invention.

FIG. 8 is a cross-sectional view showing a conventional coating device.

[Explanation of symbols]

 46 coating device 50 spin chuck (rotating and holding means) 58 resist liquid (treatment liquid) 60A outer container 60B inner container 68 cleaning liquid 70 cleaning liquid discharge nozzle 78 cleaning liquid intrusion prevention step 80 cleaning liquid infiltration prevention gap 82 resist liquid supply nozzle 84 liquid pool W Semiconductor wafer (processing target)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number in the agency FI Technical indication location H01L 21/68 P 8418-4M (72) Inventor Akihiro Fujimoto 2655 Tsukuri Tsukuyo, Kikuchi-gun, Kumamoto Prefecture Within Tokyo Electron Kyushu Co., Ltd.

Claims (1)

[Claims] 1. A processing liquid is applied to a target object held by a rotation holding means having a flat upper surface while rotating the target object, and the processing liquid adhering to the back surface of the target object is discharged from a cleaning liquid discharge nozzle. In a coating device configured to clean with the discharged cleaning liquid, a peripheral portion of the upper surface of the rotation holding means is provided for preventing the cleaning liquid from entering when the object is placed and held on the upper surface. A coating apparatus, wherein a cleaning liquid intrusion prevention step portion for forming a cleaning liquid infiltration prevention gap is formed.