JPH07245256A - Developing of photoresist and device thereof - Google Patents

Abstract

PURPOSE:To eliminate an uneven development due to the unevenness of a temperature distribution in a wafer and to make it possible to develop a pattern in an even size within the surface of the wafer. CONSTITUTION:A wafer 12 is rotated by a spin chuck 2, which has the total area of vacuum exhaust vents capable of obtaining an enough suction force to hold the wafer 12 and has a high temperature, while being held by the chuck 2, a developing solution is dripped on the NC), surface of a photoresist within a time when the unevenness of a temperature distribution in the wafer 12 is not caused by a temperature transfer from the chuck 2, the developing solution is dispersed while the balance between the centrifugal force of the wafer and the surface tension of the photoresist is kept, a thin solution layer 13 is formed and after that, a developing reaction is made to proceed in a state that the rear of the wafer 12 is supported by projected rods 7 in a point contact.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoresist developing method and its apparatus, and more particularly to a photoresist developing method and apparatus for developing a photoresist applied on a glass substrate of a semiconductor wafer or a liquid crystal display panel.

[0002]

2. Description of the Related Art Generally, in manufacturing a semiconductor device or a liquid crystal display device, various patterns are formed on a semiconductor wafer or a glass substrate, which is a substrate, by etching to form semiconductor elements or wirings.

When a pattern is formed by this etching method,
For example, a semiconductor wafer (hereinafter simply referred to as a wafer) is coated with a photoresist, and the photoresist film formed by the coating is irradiated with ultraviolet light or an electron beam through the mask to transfer the pattern of the mask. The photoresist film having the transferred pattern was developed with a developing solution to form a mask pattern.

This photoresist developing apparatus has a rotary table having a vacuum exhaust hole which is in communication with a vacuum source over the entire surface of contact with the wafer and which holds and rotates the wafer by suction.
The wafer was equipped with a nozzle for dropping the developing solution. Then, the developing solution is dropped from the nozzle on the rotated wafer to form a uniform thin liquid layer by dispersing the developing solution on the entire surface of the wafer while balancing the rotational centrifugal force and the surface tension.
The photoresist on the wafer was developed by allowing the wafer to be held on a turntable for a predetermined time.

[0005]

However, in the above-described conventional developing device, the rotary shaft of the rotary table is usually directly connected to the motor, and the temperature of the rotary table increases due to the heat generated by the motor. Further, although the temperature of the developer to be dripped is controlled and maintained at a constant temperature, the temperature control temperature and the temperature of the rotary table do not always match and the temperature of the rotary table is higher. For these reasons, a difference in temperature occurs between a portion of the wafer that is in contact with the rotary table surface and a portion that is not in contact with the surface of the wafer, and the temperature distribution in the wafer surface becomes non-uniform. As a result, the development speed of a photoresist having a high temperature dependency is high in a high temperature area and low in a low temperature area, resulting in a non-uniform photoresist pattern size after development. In particular, in recent years, the pattern has become finer and finer with higher integration, and this problem has become a serious problem.

The problem of quality due to the uneven temperature distribution is found not only in the developing step but also in the photoresist coating step which is the preceding step. This problem is a problem that the film thickness of the photoresist film becomes uneven due to the nonuniform temperature. A photoresist coating device that eliminates the uneven film thickness due to the uneven temperature distribution is disclosed in Japanese Examined Patent Publication No. 62-14
It is disclosed in Japanese Patent No. 5378.

In this coating apparatus, a suction portion having an arc-shaped suction hole is partially projected on the periphery of the rotary table, and the suction hole is vacuumed through a vacuum port formed inside the rotary table and the rotary shaft. It is configured such that only the peripheral portion of the wafer, which is connected to the power source and mounted on the rotary table, is held by vacuum suction. That is, in this device, since the central portion of the wafer can be held without contacting the rotary table at all, it is prevented that the temperature distribution of the wafer becomes non-uniform due to the contact with the rotary table, and the wafer is coated. The feature is that the film thickness of the photoresist is uniform.

When it is considered that the rotary table having such a structure is applied to this developing apparatus, it seems that uneven development due to uneven temperature distribution can be solved at first glance, but normally, the temperature dependence of the development reaction of the photoresist is It is much higher than the temperature dependence of the curing reaction of the photoresist, and even if the contact area with the wafer is small and it is provided in the peripheral part, as long as it is in contact, there is a difference in temperature difference due to heat transfer in that part. Even if the temperature distribution is not uniform on the wafer and the reaction occurs depending on the temperature, uneven development occurs on the wafer surface.

Further, if the vacuum exhaust holes are limited to only the peripheral portion in order to reduce the contact area with the vacuum exhaust holes for adsorbing, the force for holding the wafer is weakened accordingly, and the centrifugal force of the wafer when rotating is exerted. Including the problem of leaving the turntable. In particular, it cannot be applied to a heavy glass substrate for liquid crystal. Further, the protrusion of the peripheral portion causes a depression to be formed in the central portion, which makes it difficult to remove the developing solution and causes a new problem of contaminating a newly developed wafer.

Therefore, an object of the present invention is to provide a photoresist developing method and apparatus capable of developing a pattern having a uniform size in the surface of a substrate to be processed without uneven development caused by uneven temperature distribution of the substrate to be processed. To provide.

[0011]

A feature of the present invention is that a developing solution is dropped onto a substrate to be processed whose main surface is coated with a photoresist, and the substrate is rotated while holding it in surface contact with the back surface of the substrate to be processed. Then, the developing solution is dispersed outwardly by the centrifugal force caused by rotation to form the developing solution film on the photoresist surface, and then the back surface of the processing target substrate is supported by point contact with the processing target substrate stopped. It is a photoresist developing method in which the developer is reacted with the photoresist to develop.

Another feature of the present invention is that the rotary table has a flat surface that comes into contact with the back surface of the substrate to be processed and a vacuum exhaust hole for adsorbing the substrate to be processed, for rotating the substrate to be processed. A nozzle for dropping the developing solution onto the substrate to be processed placed on the rotary table, a plurality of projection members for supporting the substrate to be processed in point contact, and the projection member and the rotary table relative to each other. And a vertically moving mechanism for vertically moving the photoresist.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing a photoresist developing apparatus for explaining an embodiment of the photoresist developing method and apparatus of the present invention. As shown in FIG. 1, this photoresist developing apparatus has a disk-shaped spin chuck 2 that has a flat surface that contacts the wafer 12 and that has a vacuum exhaust hole that adsorbs the wafer 12, and that rotates the wafer 12. Wafer 1 mounted on spin chuck 2
2, a developing nozzle 5 for dropping a developing solution, a plurality of protruding rods 7 for supporting the back surface of the wafer 12 in point contact therewith, and an elevating mechanism 6 for vertically moving the protruding rods 7.

Further, in the same manner as in the prior art, this apparatus also includes a developing cup 1 having a waste liquid outlet for wrapping and accommodating the spin chuck 2, the projecting rod 7, the developing nozzle 5 and the cleaning nozzle 11 and discharging the developing solution and the cleaning solution. A lid 1a for opening and closing the opening of the developing cup 1, a motor 4 directly connected to the rotation shaft 3 of the spin chuck 2, and a vacuum pump connected to a vacuum pipe communicating with a vacuum exhaust hole of the spin chuck 2 are provided. There is.

The elevating mechanism 6 simultaneously moves up and down a plurality of protruding rods 7, and this operation pushes the wafer 12 upward from the spin chuck 2 or the wafer 1.
2 is lowered and placed on the spin chuck 2. The speed of the vertical movement of the protruding bar 7 is
When the wafer 2 is to be mounted on the protrusion bar 7 or is to be transferred or mounted from the spin chuck 2, the speed becomes slower as the tip approaches the wafer so that the wafer 12 is not impacted.

For this reason, the elevating mechanism 6 employs a screw feed type mechanism. In other words, this lifting mechanism has a motor 8 whose rotation speed is variable, a gear 9a attached to the shaft of the motor 8, a nut coaxially mounted on a gear 9b meshing with the gear 9a, and a rotation of the nut. The feed screw 10 moves up and down, and a support member that is attached to the tip of the feed screw 10 and holds the rear ends of at least three protruding rods 7. Of course, a pneumatic cylinder or a hydraulic cylinder may be used more easily than the motor feed. However, in this case, it is important to consider that the above-mentioned speed control is performed in the design.

Further, the spin chuck 2 may be moved up and down instead of moving the protrusion bar 7 up and down. However, in this case, the elevating mechanism becomes complicated and it may cause a failure, so it is not always a good idea. In addition, the developer cup 1 usually has a lid 1
Since a is attached, it is desirable that the protrusion rod 7 be elongated and the stroke be increased so that the wafer 12 comes out above the opening surface of the developing cup 1 as shown by the chain double-dashed line. This simplifies the operation of the wafer loading and unloading mechanism and makes the delivery of the wafer more reliable. Of course, the wafer 12 can be stopped at an intermediate point between this opening surface and the surface of the spin chuck 2.

FIG. 2 is a view showing the vicinity of a spin chuck for explaining one embodiment of the photoresist developing method by the photoresist developing apparatus of FIG. Next, the operation of the above-described photoresist device and the photoresist developing method will be described with reference to FIGS. 1 and 2.

First, as shown in FIG. 2 (a), the protruding rod 7
Is raised and stopped at the place where the front end projects from the opening surface of the developing cup 1. Next, the wafer 12 is placed on the tip of the protruding rod 7 from a loader (not shown). Next, as shown in FIG. 2B, the protrusion rod 7 is lowered by the operation of the elevating mechanism 6 to transfer the wafer 12 onto the spin chuck 2 and evacuate and hold it. Then, the spin chuck 2 is rotated and the developing solution is dropped from the developing nozzle 5. As a result, the developing solution spreads outward and a thin liquid layer 13 is formed on the photoresist surface of the wafer 13 while maintaining the balance between the centrifugal force due to the rotation of the spin chuck 2 and the surface tension of the developing solution. This operation is performed in an extremely short time of 1 to 2 seconds, and there is no temperature transfer from the spin chuck 2 to the wafer 12, so that the temperature distribution of the wafer 12 does not become uneven.

Next, the developing nozzle 5 is rotated to rotate the wafer 1.
2), and as shown in FIG. 2C, the protrusion rod 7 is raised to the midpoint within a short time so that the development reaction of the photoresist is not partially progressed, and the vacuum of the spin chuck 2 is exposed to the atmosphere. The suction force of the returned wafer 12 is eliminated, the wafer 12 is brought into contact with the tip end portion of the protruding rod 7, and the wafer 12 is placed on the protruding rod 7. And the time required for development, for example,
The wafer 12 is kept on the protruding rod 7 until about 60 seconds have passed.

When the development is completed after the lapse of a predetermined time, the protrusion bar 7 is lowered again to transfer the wafer 12 to the spin chuck 2, and the wafer 2 is sucked and held by vacuum exhaust from the vacuum exhaust hole. Then, while rotating the spin chuck 2, the cleaning nozzle 11 is pushed onto the wafer 12, and the cleaning liquid is applied to the wafer 12 from the cleaning nozzle 11 to wash away the residual developer. Then, when the cleaning is completed, the wafer 12 is rotated at a high speed to scatter the cleaning liquid by centrifugal force to dry it.

After the wafer 12 is dried, the cleaning nozzle 11 is pulled in, the vacuum of the spin chuck 2 is returned to the atmosphere, and the protrusion bar 7 is raised to lift the wafer 12 from the spin chuck 2 as shown in FIG. 2 (a). The wafer 12 is placed on the projecting rod 7, and the projecting rod 7 is further raised to project the wafer 12 from the opening surface of the developing cup 1. Then, the wafer 12 is removed from the protruding bar 7 by an unloader (not shown). This operation is repeated to develop the photoresist on many wafers.

On the other hand, in the case of a liquid crystal substrate, a wafer which is a semiconductor substrate is processed in the same manner as a wafer by only replacing the glass plate. However, this glass plate is thicker and heavier than a wafer, and has a rectangular shape that is difficult to balance in rotation. Therefore, if the spin chuck is eccentrically attached, the glass plate may be detached from the spin chuck due to the centrifugal force generated by the rotation. In other words, when attaching the glass plate to the spin chuck, it is necessary to align the center of the glass plate with the rotation center of the spin chuck. Therefore, the photoresist developing apparatus applied to the glass plate is to provide the protrusion bar with a positioning mechanism for aligning the glass plate and the rotation center of the spin chuck.

FIG. 3 is a perspective view showing a modified example of the protruding bar of FIG. A plurality of protruding rods having this positioning function are shown in FIG.
As shown in FIG.
It is composed of two fixing protruding bars 7a in the X direction and the Y direction which are positioned at the center of rotation, and two pressing bars 7b for pressing the glass plate 14 against the fixing protruding bars.

The fixing projection bar 7a is formed by cutting off the tip of the round bar to form a wall surface perpendicular to the mounting surface so that the mounting surface of the glass plate 14 and the side surface of the glass plate 14 contact each other. Further, the pressing protrusion bar 7b has a structure in which a hole is formed in the lateral direction at the tip of a round bar, and a ball 15 and a spring 16 for applying a pressing force to the ball 15 are inserted into this hole. Therefore, the protruding rods 7a, 7b
The glass plate placed on is pressed by the spring 16 via the ball 15 toward the fixing protruding bar 7a and positioned. Further, since the ball 15 is used as the pressing member, the glass plate 14 can be easily inserted and removed with a small force.

FIG. 4 is a sectional view showing another embodiment of the photoresist developing apparatus of the present invention. As shown in FIG. 4, this photoresist developing apparatus is provided with a cooling nozzle 17 that jets cooling water to cool the spin chuck 2 and clean the wafer mounting surface. Other than that is the same as the above-mentioned embodiment.

When the spin chuck 2 is cooled and washed by the cooling nozzle 17, the wafer is rotated by the spin chuck 2.
Or when it is not mounted on the protruding bar 7,
It is not always necessary to carry out every cycle, and it may be carried out periodically according to the number of processed sheets. Pure water is desirable as the cooling water, and its temperature is the same as or slightly lower than that of the temperature-controlled developer, and the spin chuck 2 having a high temperature is cooled to eliminate the difference from the temperature of the developer. This means that when the temperature of the spin chuck 2 is extremely lowered by cooling water, heat is conversely taken from the wafer, the temperature of the temperature-controlled developer drops, the developing speed is lowered, and the processing capacity of the apparatus is reduced accordingly. It will be.

Further, in order to improve the cleaning effect on the mounting surface of the spin chuck 2, the cooling nozzle 17 is periodically moved in the direction of the arrow while rotating the spin chuck 2. As a result, the developer adhering to the mounting surface of the spin chuck 2 in the pretreatment can be completely washed away.

[0030]

As described above, according to the present invention, the substrate to be processed is held by the rotating table surface having a high vacuum exhaust hole total area and a sufficient suction force for holding the substrate to be processed. Rotate and drop the developer onto the photoresist surface of the substrate to be processed within a time period that does not cause uneven temperature distribution on the substrate due to temperature transfer, and distribute the developer while balancing the centrifugal force and surface tension. To form a developer film, and then
By carrying out the development process by advancing the development reaction while the back surface of the substrate to be processed is supported by point contact, uneven development due to uneven temperature distribution of the substrate to be processed due to transfer from a high temperature is eliminated, and There is an effect that development can be performed without variation in pattern dimensions.

Further, even for a substrate to be processed which is heavy and difficult to balance in rotation, by providing means for aligning the center of rotation of the substrate to be rotated with the center of rotation of the turntable, the substrate to be processed can be moved from the turntable. It can be developed without removing it.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a photoresist developing apparatus for explaining an embodiment of a photoresist developing method and apparatus of the present invention.

FIG. 2 is a diagram showing the vicinity of a spin chuck for explaining an example of the photoresist developing method by the photoresist developing apparatus of FIG.

FIG. 3 is a perspective view showing a modified example of the protruding bar of FIG.

FIG. 4 is a sectional view showing another embodiment of the photoresist developing apparatus of the present invention.

[Explanation of symbols]

 1 Development Cup 1a Lid 2 Spin Chuck 3 Rotating Shaft 4, 8 Motor 5 Development Nozzle 6 Lifting Mechanism 7, 7a, 7b Protrusion Rod 9a, 9b Gear 10 Feed Screw 11 Cleaning Nozzle 12 Wafer 13 Thin Liquid Layer 14 Glass Plate 15 Ball 16 Spring 17 Cooling water nozzle

Claims (5)

[Claims] 1. A developing solution is dropped onto a substrate to be processed whose one surface is coated with a photoresist, and is rotated while being held in surface contact with the back surface of the substrate to be processed, and the developing solution is rotated by centrifugal force to rotate the developing solution. Disperse outwardly to form the developer film on the photoresist surface, and then, while the substrate to be processed is stopped, support the back surface of the substrate to be processed by point contact to cause the developer to react with the photoresist. A method of developing a photoresist, which comprises developing. 2. The photoresist developing method according to claim 1, wherein the substrate to be processed is a semiconductor wafer or a glass plate. 3. A rotary table having a flat surface in contact with the back surface of the substrate to be processed and having a vacuum exhaust hole for adsorbing the substrate to be processed, and a rotary table for rotating the substrate to be processed, and mounted on the rotary table. A nozzle for dropping the developing solution onto the processed substrate, a plurality of projecting members for supporting the process substrate in point contact, and an elevating mechanism for vertically moving the projecting member and the rotary table relative to each other. A photoresist developing apparatus comprising: 4. The photoresist developing apparatus according to claim 3, wherein the protrusion member is provided with means for determining a position of the substrate to be processed, which is mounted on the rotary table. 5. The photoresist developing apparatus according to claim 3, further comprising a nozzle that ejects a liquid medium that cools the turntable.