JPH11186123A - Development of photosensitive film formed on wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a development method in which neither dissolved photosensitive film particles nor fine residues of a developer and a cleaning solvent remain on a wafer even of the rotating speed of the wafer is reduced. SOLUTION: A wafer 10, in which a material layer 11 for forming a desired pattern and a photosensitive film 12 coated on the layer 11 are formed, is attached to a wafer holder 14 so that the surface of the film 12 faces the ground. Then, a developer 28 is jetted onto the surface of the film 12 using a developer jetting unit 16 to thereby cause the film 12 to react with the developer 28. A cleaning solvent is thereafter jetted onto the surface of the film 12, which has already been jetted with the developer 28, using the cleaning solvent jetting unit 16. The developer jetting step and the cleaning solvent jetting step are performed while the water is being rotated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a semiconductor device, and more particularly, to a method for developing a photosensitive film formed on a wafer.

[0002]

2. Description of the Related Art Generally, a semiconductor device is manufactured through a number of steps. A photo process for forming a material layer formed on a wafer into a desired pattern from such many processes is an essential process for manufacturing a semiconductor device. Such a photo process includes a coating process of forming a photosensitive film, for example, a photoresist film on a wafer,
An exposure step of selectively irradiating predetermined regions of the photoresist film with light such as ultraviolet light, and a development step of developing the photoresist film on the wafer after the exposure step is completed to form a photoresist pattern of a desired form. including.

On the other hand, the conventional developing process proceeds with the surface of a photosensitive film formed on a wafer facing upward.
At this time, the photosensitive film dissolved in the developing solution during the developing process is present as fine particles in the developing solution. In such a conventional developing process, the removal of the dissolved photosensitive film particles, the developing solution and the cleaning solution existing on the wafer is performed by rotating the wafer and bouncing out of the wafer by centrifugal force. .

However, if the wafer is rotated with the surface of the photosensitive film facing upward, in order to remove the dissolved photosensitive film particles, the developing solution and the cleaning solution present on the wafer,
The photosensitive film particles dissolved in the developing solution, the developing solution and the cleaning solution are accelerated by the centrifugal force and collide with the side wall of the photosensitive film pattern. As described above, in the conventional developing process, when a force is applied to the side wall of the photosensitive film pattern, the photosensitive film pattern having a small contact area with the lower film is pressed, falls, or is separated from the substrate. Thus, there is a problem that a desired pattern cannot be formed sufficiently.

[0005] The problem that the photosensitive film pattern is pushed or collapsed often occurs particularly near the edge of the wafer. The larger the diameter of the wafer, the larger the area where the pattern is generated. This will increase the defective rate. In the conventional developing process, a method of reducing the rotation speed of the wafer is used to minimize the problem caused by the centrifugal force. However, when the rotation speed is reduced, the dissolved photosensitive film particles, the developing solution and the cleaning solution are not sufficiently repelled by the substrate. Therefore, even after the development process is completed, fine residues of the photosensitive film particles and the developing solution and the cleaning solution dissolved on the wafer remain, thereby causing other problems.

On the other hand, as another method for minimizing such a problem due to the centrifugal force, the contact area between the photosensitive film pattern and the lower film is increased by reducing the diameter of the wafer or increasing the pattern size. Although there is a method, this is a contradictory method in view of the current technology trend in which semiconductor devices are highly integrated and the size of a wafer is enlarged, and it is very difficult to realize the method.

[0007]

SUMMARY OF THE INVENTION The present invention has been devised in order to solve the above-mentioned problems, and the photosensitive film particles dissolved on the wafer can be developed even when the rotation speed of the wafer is reduced. It is an object of the present invention to provide a developing method in which fine residues of a liquid and a cleaning liquid do not remain.

[0008]

According to the present invention, there is provided a method for developing a photosensitive film formed on a wafer, comprising the steps of: forming a material layer for forming a desired pattern; and coating the material layer with the material layer. Mounting the exposed wafer on which the photosensitive film is formed in a wafer holder such that the surface of the photosensitive film faces downward, and injecting a developing solution onto the surface of the photosensitive film using a developer injecting device to expose the photosensitive film; The method includes reacting the film with the developing solution, and injecting a cleaning solution onto a surface of the photosensitive film reacted with the developing solution using a cleaning solution spraying device. The step of spraying the developing solution and the step of spraying the cleaning solution are performed while the wafer is rotating.

The developing liquid ejecting apparatus and the cleaning liquid ejecting apparatus may be the same ejecting apparatus or different ejecting apparatuses. It is preferable that the number of the developing solution ejecting devices and the number of the cleaning solution ejecting devices are plural, and it is preferable that the developing solution ejecting device and the cleaning solution ejecting device move along the surface of the photosensitive film. It is desirable to apply a slight vibration to the wafer for a smooth reaction during the reaction of the developer.

The rotational speed of the wafer is a composite component of the force of the weight of the fine particles of the photosensitive film dissolved in the development reaction stage, the weight of the washing solution and the developing solution, and the centrifugal force of the rotating motion of the wafer. Is desirably adjusted so as to be inclined with respect to the side wall of the photosensitive film pattern. Before performing the developing solution reaction step, a pre-rinsing step may be further included.

The method for developing a photosensitive film formed on a wafer according to the present invention is to reduce the rotational speed of the wafer by about 1,000 rpm while maintaining a sufficient rinsing effect by the effect of gravity as compared with the conventional method. Therefore, it is possible to prevent the photoresist pattern from collapsing due to the centrifugal force and to prevent the development from being pushed, thereby reducing the defective rate of the semiconductor element.

Also, desired results can be expected if the present invention is applied not only to currently used 8-inch wafers but also to 12-inch wafers. This is desirable in view of the trend that a sufficient rinsing effect is required to be achieved while further reducing the rotation speed of the wafer in a developing process in accordance with an increase in the diameter of the wafer.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments according to the present invention will be described below in detail with reference to the accompanying drawings. However, it should not be construed that the present invention is limited to the following embodiments. In the drawings, the thickness of layers, regions, and the like are exaggerated for clarity. The same reference numerals in the drawings denote the same components.

In general, the developing process is performed through a pre-rinsing step, a developing step, and a post-rinsing step. In the pre-rinsing step, the surface of the photosensitive film such as a photoresist is washed and the temperature is adjusted, and in the post-rinsing step, the developing solution discharged on the photosensitive film surface during the developing process is washed away. A wafer having a material layer for forming a desired pattern and a photosensitive film coated on the material layer is subjected to an exposure process and a pre-rinse process, and then a development process is performed. The development step is roughly divided into a developer discharge step and a development reaction step.

In the developing solution discharging step, the developing solution is discharged onto the wafer having the photosensitive film formed thereon by an injection device such as a nozzle. At this time, the developer should be uniformly and simultaneously discharged onto the entire surface of the photosensitive film. In the developing reaction step, the developing solution uniformly discharged on the photosensitive film in the developing solution discharging step selectively dissolves the exposed portion of the photosensitive film. At this time, if the developing solution is affected by the physical force, a part of the unexposed photosensitive film side wall reacts with the developing solution, so that the exposed portion of the photosensitive film and the developing solution are affected by the physical force. It is desirable that the rotational speed of the wafer be adjusted so that a pure chemical reaction occurs without being affected.

During the development reaction step, the wafer goes through a post-rinse step in order to remove the photosensitive film and the developer dissolved by reacting with the developer from the wafer.
In the post-rinsing step, the dissolved photosensitive film and the developing solution are removed from the wafer by using a cleaning solution sprayed from a spraying device such as a nozzle, and at this time, the wafer is rotated to appropriately remove the dissolved photosensitive film and the developing solution. By applying a gentle centrifugal force, it can be efficiently removed.

However, the above-described problem due to the centrifugal force mainly occurs from the post-rinsing stage. Therefore, the present invention is to improve the post-rinsing step to minimize the problem due to the centrifugal force. FIG. 1 is a schematic view for explaining the developing method of the present invention.

Referring to FIG. 1, a wafer 10 on which a material layer 11 such as an oxide film and a photosensitive film 12 such as a photoresist are sequentially formed is placed on a wafer holder 14 having a vacuum chuck. I do. At this time, the surface of the photosensitive film 12
Unlike the conventional method in which the surface 12a is placed upward, in the method of the present invention, the surface 12a of the photosensitive film 12 is placed downward. Placing the surface 12a of the photosensitive film 12 facing downward is not only the centrifugal force but also the centrifugal force when the dissolved photosensitive film and the developing solution are removed from the wafer from the development reaction stage, and the centrifugal force described above is applied. This is to minimize problems caused by force. Then, in order to develop the photosensitive film 12, a developing solution is ejected from an ejecting device 16 such as a nozzle toward the surface 12a of the photosensitive film 12 (developing solution discharging step). Preferably, a pre-rinsing step is performed before the developing solution discharging step.

After the developing solution discharging step is performed, a developing solution reaction step is subsequently performed. At this time, it is desirable to apply fine vibration to the wafer for a smooth reaction. The developer reaction step is described in detail again below. In order to remove the photosensitive film and the developing solution dissolved in the developing solution reaction step from the wafer, the cleaning liquid 18 is sprayed from the spraying device 16 toward the surface 12a of the photosensitive film 12 (post-rinsing step). Although only one injection device 16 is shown in FIG. 1, a plurality of injection devices 26a, 26b, 26c can jet the cleaning liquids 27, 28, 29 as shown in FIG. 2, and the number of the injection devices varies according to need. be able to.
Further, the developing solution and the cleaning solution can be jetted from the same jetting device as shown in FIG. 1, or can be jetted from different jetting devices. In FIG. 2, reference numerals 20, 21, and 22 denote a wafer, a material layer for forming a desired pattern, and a photosensitive film, respectively, as in FIG. Reference numeral 22a indicates the surface of the photosensitive film, and reference numeral 24 indicates a wafer holder. Injection device 16 or 26a, 26b, 26c can also move along surface 22a or 22a of photosensitive film 12 or photosensitive film 22 for efficient rinsing.

In a developing step including a developing liquid discharging step and a developing liquid reaction step and a post-rinsing step, a wafer holder is provided.
The wafer 10 or the wafer 20 installed on the wafer holder 14 or the wafer holder 24 is rotated in the a or b direction by a device (not shown) that generates a rotational motion such as a motor,
Or rotate in the opposite direction. At this time, the rotation speed of the wafer may be different between the developing stage and the post-rinsing stage. FIG. 3 is an enlarged cross-sectional view of the portion A in FIG. 1, and shows that the photosensitive film portion and the developing solution dissolved in the developing solution in the developing reaction step are removed from the wafer while following the post-rinsing step.

Referring to FIG. 3, a portion 32 of the photosensitive film 12 exposed in the exposure process is dissolved in a developing solution, and a portion 34 of the photosensitive film 12 not exposed in the exposing process is not dissolved in the developing solution. . The portion 32 of the dissolved photosensitive film 12 remains as fine particles 36 in the developer. As shown in FIG. 3, in the developing method of the present invention, in the post-rinsing step, such fine particles 36 and the developing solution and the cleaning solution do not remain on the wafer 10 and the portion of the photosensitive film 12 that has not been exposed. This is to minimize the influence of the fine particles 36 and the liquid due to the centrifugal force on the liquid crystal 34 (that is, the photosensitive film pattern). For this purpose, by appropriately adjusting the rotation speed of the wafer and adjusting the own weight of the fine particles 36 and the liquid due to the gravity and the centrifugal force accompanying the rotation of the wafer, the fine particles 36 and the liquid are removed from the wafer 10 by c.
Alternatively, it can be bounced in the direction d (that is, in a direction that does not hit the side wall of the photosensitive film pattern). At this time, the rotation speed of the wafer depends on the line width and height of the photosensitive film pattern, and also depends on the degree of adhesion between the photosensitive film pattern and the lower film (that is, the type of the lower film). In the above, the development process of the positive photoresist has been described.
The process is the same except that the unexposed portion of the photosensitive film is developed even in the case of developing the negative photoresist.

Next, a comparative example with the present invention will be described. In order to compare the conventional developing method with the developing method of the present invention, first, as shown in FIG. 4, a plurality of 8-inch wafers 40 on which an oxide film 41 and a photosensitive film 42 are sequentially formed are prepared. The exposure process was performed on the photosensitive film formed on the wafer. According to the conventional developing method and the developing method of the present invention, a width of 0.15 to 0.5 μm (approximately 0.3 μm) is applied to the exposed photosensitive film 42 using the different wafers 40.
Thus, a photosensitive film pattern having a height of 4,000 to 10,000 angstroms was formed. As a result, the 8-inch wafer 40
In the case where the line width is 0.3 μm or less, in the conventional developing method, when the rotation speed of the wafer 40 is approximately 3,500 rpm or less, the photosensitive film particles dissolved in the edge of the wafer 40 and the developing solution due to a decrease in the rinsing effect due to the centrifugal force. And a fine residue of the washing liquid remained.

On the other hand, in the case of the developing method according to the present invention,
Even when the rotation speed of the wafer 40 was approximately 2,500 rpm, no dissolved photosensitive film particles and fine residues of the developing solution and the cleaning solution remained on the edge of the wafer 40. Here, when developing a photosensitive film formed on an 8-inch wafer, the line width is
When the thickness is 0.3 μm, the rotation speed of the wafer should be approximately 3,000 rpm or less in order to minimize the problem that the photosensitive film pattern is pushed or collapsed by the centrifugal force accompanying the rotation of the wafer.

Therefore, the developing method of the present invention, in which the rotation speed of an 8-inch wafer can be reduced to 3,000 rpm or less, can achieve a sufficient rinsing effect while minimizing the problems associated with centrifugal force.

Although the present invention has been described in the above embodiments, the present invention is not limited to the examples shown in the above-described embodiments, and the present embodiments are merely examples of the present invention. The purpose of the present invention is to provide a complete disclosure and completely inform the person of ordinary knowledge of the scope of the invention. Various persons within the technical idea and scope of the present invention may be provided by those of ordinary skill in the art. Obviously, modifications and improvements are possible.

[0026]

As described above, the method of developing a photosensitive film formed on a wafer according to the present invention is more effective than the conventional method in that a sufficient rinsing effect is achieved by the effect of gravity while the rotational speed of the wafer is reduced. Can be reduced by about 1,000 rpm, so that the photoresist pattern can be prevented from collapsing due to the centrifugal force and the pushed development can be prevented, and the defective rate of the semiconductor element can be reduced.

[0027] Also, a desired result can be expected even when applied to a 12-inch wafer as well as an 8-inch wafer currently in use. This can be said to be desirable in view of the trend that it is required to reduce the rotational speed of the wafer in the developing process and to achieve a sufficient rinsing effect by increasing the diameter of the wafer.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram illustrating a developing method of the present invention.

FIG. 2 is a view showing that there are a plurality of injection devices shown in FIG. 1;

FIG. 3 is an enlarged cross-sectional view enlarging A in FIG. 1;

FIG. 4 is a cross-sectional view showing a sample for comparing the present invention with a conventional technique.

[Description of Signs] 10: Wafer 11: Material layer 12: Photosensitive film 12a: Surface of Photosensitive film 12: Wafer holder 16: Injecting device 18: Cleaning liquid

Claims (10)

[Claims] 1. A wafer on which a material layer for forming a desired pattern and an exposed photosensitive film coated on the material layer are formed is mounted on a wafer holder such that the surface of the photosensitive film faces downward. A step of injecting a developing solution onto the surface of the photosensitive film using a developing solution spray device to cause the photosensitive film to react with the developing solution; and a cleaning solution spraying device on the surface of the photosensitive film reacted with the developing solution. Injecting a cleaning liquid using the method, wherein the step of injecting the developing liquid and the step of injecting the cleaning liquid are performed while the wafer is rotating, the method of developing a photosensitive film formed on a wafer. 2. The method for developing a photosensitive film formed on a wafer according to claim 1, wherein the developing solution ejecting device and the cleaning solution ejecting device are the same ejecting device. 3. The method for developing a photosensitive film formed on a wafer according to claim 1, wherein the developing solution ejecting device and the cleaning solution ejecting device are different from each other. 4. The method for developing a photosensitive film formed on a wafer according to claim 1, wherein the number of the developing solution ejecting devices is plural. 5. The method for developing a photosensitive film formed on a wafer according to claim 1, wherein the number of the cleaning liquid ejecting apparatuses is plural. 6. The method for developing a photosensitive film formed on a wafer according to claim 1, wherein the developer spray device moves along the surface of the photosensitive film. 7. The method for developing a photosensitive film formed on a wafer according to claim 1, wherein the cleaning liquid spraying device moves along the surface of the photosensitive film. 8. The method for developing a photosensitive film formed on a wafer according to claim 1, wherein a minute vibration is applied to the wafer during the reaction of the developing solution. 9. The rotation speed of the wafer is determined by the difference between the weight of the fine particles of the photosensitive film dissolved in the developing reaction step, the weight of the cleaning solution and the developing solution, and the centrifugal force of the rotating motion of the wafer. 2. The method according to claim 1, wherein the direction of the synthesized component is adjusted so as to be inclined with respect to the side wall of the photosensitive film pattern. 10. The method of claim 1, further comprising a pre-rinsing step before performing the developing solution reaction step.
3. The method for developing a photosensitive film formed on a wafer according to item 2.