JPS6231340B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a developing method, and an object of the present invention is to uniformly apply a developing solution to an object to be developed, such as a semiconductor wafer coated with a photosensitive resin (photoresist). In particular, an object of the present invention is to uniformly develop a mask-exposed photoresist within a relatively large diameter wafer in a semiconductor wafer kit etching process, thereby uniformly forming a fine photoresist pattern.

In current IC and LSI production, the photoetch process occupies a very important position. The photo-etch process means coating one main surface of a semiconductor wafer with photoresist → soft bake → mask pattern exposure → development → hard bake → etching.

Initially, the development process used the so-called "dip method," in which the entire wafer was immersed in a developer and rinse solution, but in recent years, due to demands for improved productivity, A method of spraying a developing solution and a rinsing solution onto the semiconductor wafer surface is being considered. This method has excellent mass productivity, and there are currently many opportunities for its adoption.

First, a conventional method of spray development will be explained with reference to FIG. A semiconductor wafer 1 is fixed by a spinner head 2 using a vacuum chuck method, and a rotating device 3
The wafer 1 is rotated at about 1000 rpm, for example. Then, the developing solution 5 is ejected in the form of mist from the tip of one nozzle 4 to develop the photoresist on the wafer 1. When applying both the developer and rinse by spraying, a separate nozzle is required for rinsing. In this method, the mist of the developer is generated by a commonly used method based on Bernoulli's principle.

However, in the above method, as a result of studies by the present inventors, it was impossible to uniformly form fine patterns, especially when developing a positive resist.The reason for this will be investigated.

In the method shown in FIG. 1, as shown in FIGS. 2 and 3, the shape in which the developer 5 hits the wafer 1 will be an elliptical jet portion 6 if the jet nozzle of the nozzle 4 has a slit shape, for example. Then, the wafer 1 is rotated around its center and a developer is applied to the entire surface. At this time, the amount of developer is different between the center and the periphery of the spouting part 6, and since the wafer 1 is rotating, the centrifugal force is acting on the liquid on the wafer 1, so naturally the center of the wafer 1 There will be excess or deficiency in development at the edges. When the minimum dimension of the resist pattern is 10 μm or more, the development variation within the wafer 1 is within the tolerance and there is no major problem. The difference in development at the edges cannot be ignored. This becomes more noticeable as the diameter size of the wafer 1 becomes larger, such as 5 inch size.

According to the inventor's study, when the nozzle 4 is kept stationary,
As shown in Fig. 2, the liquid 5 is sprayed and irradiated, the wafer 1 is rotated, the liquid 5 is applied, and the positive resist is developed to form a resist pattern. In this case, a large amount of liquid was ejected, resulting in a pattern of approximately 3.3 μm, and at the periphery of the wafer 1, the pattern was approximately 2.8 μm, which did not meet the allowable range. That is, it has been found that it is impossible to uniformly form a resist pattern of 3 μm or less using the methods shown in FIGS. 1, 2, and 3. Currently, in semiconductor integrated circuits, it is necessary to form a resist pattern of 3 μm or less due to the demand for higher density. However, uniform microfabrication is not possible using conventional spray development methods.

In the development mechanism of photoresists, the development reaction occurs quickly in negative resists, so the first
Although it is possible to achieve a certain degree of uniform development using the method shown in the figure, the development reaction of positive resists proceeds slowly, and therefore, uneven supply of the developer makes the development of positive resists largely uneven. Therefore, as mentioned above, the methods shown in FIGS. 1, 2, and 3 pose particular problems in the development of positive resists.

Note that it is also possible to irradiate the entire main surface of the wafer 1 with the jetting part 6 of the nozzle at once, but in this method, the amount of liquid jetted is greatly different between the central part and the peripheral part of the jetting part 6, and it is difficult to uniformly apply the liquid. is not possible.

The present invention was made as a result of the recognition of such problems, and in order to perform uniform development processing on a relatively large object to be developed, for example, a nozzle having a plurality of ejection holes is placed on a wafer 1 as shown in FIG. like,
The jetting portions 6a, 6b, and 6c are formed in one direction, and the nozzle is moved in a direction substantially perpendicular to this direction to uniformly supply the developer to the entire main surface of the wafer 1, thereby processing a fine pattern. It can be formed uniformly on the main surface of the body.

FIG. 5 shows an example of a photoresist developing apparatus used in the photoresist developing method according to an embodiment of the present invention.

10 is a nozzle having an introduction part 11 for atomized developer, and the developer introduced here is passed through a slit-like path 1.
Divided into three at 2, three spout ports 13a, 13
It is ejected from b and 13c. This jet hole 13a,
13b and 13c are linearly arranged in one direction,
The spouting part 14 (1) of the developer from each spout
4a, 14b, 14c) are superimposed on a silicon wafer 1 coated with, for example, a positive photoresist. The diameters of wafer 1 are 1 inch, 2 inches, and 3
inch, 4 inches, and 5 inches, so the number of jet ports can be arbitrarily set according to the diameter.In the present invention, the number of jet ports can be set arbitrarily depending on the diameter. It is important to completely cover the diametrical direction with the spouting part 14. That is, as shown in 6a, 6b, and 6c in FIG. 4, the developer is irradiated in such a manner that the trajectory of the developer completely covers the diametrical direction of the wafer 1 or more. In the method of the present invention, the nozzle 10 is
The controller 16 causes an oscillating movement via the arm 17 in a direction perpendicular to the arrangement direction of the developer jetting portions 6a, 6b, and 6c. This movement allows uniform application of the developer over the entire main surface of the wafer 1, and the swing period is determined by the control device 16.

18 is a spinner head on which the wafer 1 is placed;
Reference numeral 19 denotes a shower cut, that is, a developer outlet, which is in contact with the peripheral part of the back surface of the wafer 1, and a brush-like member 2
0 to cause the developer to fall. The wafer 1 is vacuum-adsorbed to the spinner head 2, but during development, in the present invention, the wafer 1 is either not rotated or even rotated.
Since the speed is about 50 rpm, there is a risk that the developer will flow around to the back side of the wafer 1 and the vacuum chuck will not be able to be formed. Therefore, the brush-like member 20 is brought into contact with the wafer 1, and the developer spilled from the brush-like member 20 is transmitted thereto and falls to the lower part. 20 contacts the wafer 1 by connecting the support 21 to the stopper 22 by the link 23.
Push it up.

Note that when the liquid on the wafer 1 is shaken off and the wafer 1 is dried after the development is completed, the wafer 1 needs to be rotated at high speed. At that time, the shower cut 19 is lowered at 21 and 23 to release the friction between the wafer 1 and the brush-like member 20, and the wafer 1 is rotated at high speed. Reference numeral 24 denotes a control device for controlling the rotation of the wafer 1 and vertically controlling the brush-shaped portion. With this configuration, rotational motion can be incorporated into the final drying process using the vacuum chuck method.

In addition, when forming a fine pattern of photosensitive resin on a semiconductor wafer, after development is completed, in order to improve the pattern size accuracy of the fine pattern, the developer is quickly removed from all areas on the semiconductor wafer almost simultaneously (rinsing process). It is also necessary to remove the rinse solution and dry it. Therefore, in order to perform these development, rinsing, and drying steps quickly, continuously, and simply, it is necessary to provide a mechanism for rotating the semiconductor wafer.

By using the above-described apparatus, it has become possible to uniformly apply the developer onto the wafer 1. That is,
Normally, the liquid ejected from the ejection holes is strong at the center and weak at the edges, so in the present invention, uniform development can be achieved by applying the liquid in the state shown in FIG. Furthermore, in the present invention, the wafer 1 is entirely covered in the diametrical direction with 6a, 6b, and 6c, and the developer is applied by the reciprocating movement of the nozzle without rotating the wafer 1, so that the wafer 1 is coated in the center and the periphery of the wafer 1. The state of application of the developer becomes much more uniform than in the case shown in FIGS. 1 and 2. As a result of applying the positive photoresist to the main surface of the wafer 1 and exposing it to a mask with a 3 μm pattern, and implementing the method of the present invention, the tolerance was approx.
It became possible to perform development of 0.1 μm or less over the entire main surface of the wafer 1, and it was possible to perform uniform photoresist development of 3 μm or less, which was impossible with conventional methods. As mentioned above, the present invention was particularly effective in developing positive type photoresists, which have a slow development reaction.

Furthermore, in carrying out the method of the present invention, as shown in FIG.
During development, lift up the rinsing nozzle 30 and move the developing nozzle 10 in the direction of the arrow to perform development, then move the nozzle 10 upward and direct the nozzle 30 downward to dispense the rinsing liquid as shown in Figure 4. By irradiating and rinsing in the same manner, uniform rinsing can be achieved.

As described above, the present invention enables a nozzle having a plurality of ejection holes arranged in at least one direction to eject developing solution from each ejection hole in a superimposed manner, and to spread the width of this overlapping portion onto one principal surface of the photosensitive material. A semiconductor wafer whose width is larger than the width of the semiconductor wafer coated with resin, and which is placed almost horizontally on a rotating body by moving the nozzle in a direction different from the above direction, for example, in a direction perpendicular to the above direction. By applying the solution to the entire surface and rotating and drying the semiconductor wafer after development, it is possible to perform a uniform development process over the entire main surface of the semiconductor wafer. The present invention greatly contributes to the formation of fine photoresist patterns on semiconductor wafers, and since the semiconductor wafer is rotated on a spinner head and can be performed in a single step of development, rinsing, and drying, it can fully automate the formation of fine patterns. This is highly effective for mass production.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a conventional spray developing device, FIGS. 2 and 3 are diagrams of a state in which a developer is irradiated onto a wafer surface by the device in FIG. 1, and FIG. 4 is an embodiment of the present invention. FIG. 5A is a partial cross-sectional schematic front view of a spray developing device that has a multi-hole nozzle and performs an oscillating motion used in the method of the present invention, and FIG. is A's-'
The line sectional view and FIG. 6 are schematic diagrams of a developing device used in the present invention, which is equipped with two nozzles, one for developing and one for rinsing. 1... Semiconductor wafer, 6a, 6b, 6c... Developer jetting part, 10... Nozzle, 13a, 13b, 13c
...Ejection hole, 14a, 14b, 14c...Ejection part, 1
5... Support shaft, 17... Arm, 18... Spinner head, 20... Brush shaped portion, 30... Rinse nozzle.

Claims (1)

[Scope of Claims] 1. A plurality of ejection holes for ejecting a developing solution are arranged in at least one direction, and the solution is ejected from the nozzle so that the developing solution ejected from each ejection hole forms an overlapping part. one principal surface of a semiconductor wafer coated with a photosensitive resin is placed in the overlapping section, and one principal surface of the semiconductor wafer is coated with a photosensitive resin and has one principal surface smaller in width in the one direction than the overlapping section, and the plurality of ejection holes are arranged in the one direction. is moved in different directions, the solution is applied to the entire main surface of the semiconductor wafer placed substantially horizontally on a rotating body, and after development, the semiconductor wafer is rotated and dried. 2. The developing method according to claim 1, characterized in that a solution deriving body is brought into contact with the other main surface of the semiconductor wafer. 3. The developing method according to claim 1, wherein the photosensitive resin is positive type.