JPH03122648A - Developing method for positive type photoresist - Google Patents

Abstract

PURPOSE:To prevent the occurrence of irregularity of development with simple operation by controlling the supply timing of pure water, developer and pure water. CONSTITUTION:At a prerinsing stage, the supply of the pure water is stopped after starting the supply of the developer, and the supply of the developer is stopped after starting the supply of the washing pure water. For example, the pure water 2 is supplied from a pure water feeding nozzle 6 to all the surface of a photoresist. Next, the developer 3 is supplied to all the surface of the photoresist 4 through a developer feeding nozzle 7. The supply of the pure water 2 is stopped three seconds after starting the supply of the developer 3, and the supply of only the developer 3 is performed for 20 seconds. Then, the supply of the pure water 2 for washing is started just before completing the supply of the developer 3 and the supply of the developer 3 is stopped. The supply of the pure water 2 is performed for 60 seconds. After completing the above-mentioned stage, the revolving speed of a table 5 is made high and the blow of N2 is performed to dry a substrate 1. Thus, the irregularity of development is prevented from occurring.

Description

[Detailed explanation of invention] (Usage field in industrial industrial) The present invention is related to the development method of the positive photo resist, and in more detail, adjust the supply of pure water, development liquid and cleaning pure water. The present invention relates to a method for developing a positive photoresist, which aims to eliminate unevenness in development.

(Prior art and its problems) Photoresist is coated on the surface of a wafer and developed by dropping a chemical onto the center of the wafer held in a wafer chuck on a rotatable turntable, and while rotating the turntable. Spin method for developing,
A dip method is known in which development is performed by immersion in a tank containing a developer and a cleaning solution. Among these, the spin method has recently become the main method because it is easy to control development and has a high throughput.

In the case of the spin method, a substrate with a photoresist layer on its surface that has been exposed to some pattern using a laser or ultraviolet light is placed on a rotating turntable, and while the substrate is being rotated, a spray is applied from a nozzle opening upward. , by showering or dripping the developer,
Pure water is supplied in this order to perform development. In other words, first, the photoresist surface is made to adapt to the water by forming a water film on the photoresist surface using pure water, and then the exposed portions of the photoresist are decomposed by flowing a developer using one of the methods mentioned above.・Melting to form a pattern. When the development is completed, the supply of the developer is stopped and at the same time, pure water is supplied to wash away the developer.

After that, water is removed by rotating the turntable at high speed, and nitrogen gas is blown to dry the wafer, thereby completing the development process.

However, even with this development method, since the photoresist is water repellent, it is not compatible with water and it is difficult to form a uniform film of water on the photoresist surface, making it difficult to develop the photoresist surface. The switching between the liquid and the liquid tends to be uneven, and as a result, when developing the photoresist,
Local development unevenness is likely to occur, and such development unevenness becomes significant when developing a photoresist with a submicron film thickness.

Also, when supplying water when stopping development,
The time for switching from developer to water must be short and uniform, and since this switching is difficult to perform smoothly, there is a problem in that uneven development is likely to occur in this case as well.

As a means to prevent such uneven development.

It is possible to appropriately control the rotation speed of the turntable, the amount of pure water, and the amount of developer, but it is extremely difficult to set the conditions for such control means, and it is difficult to control the amount of rotation of the turntable and the amounts of pure water and developer. Also, uneven development occurs due to changes in liquid temperature, and both of these causes a decrease in product yield.

JP-A No. 60-243655 discloses that in order to prevent such uneven development, 1%
A method is disclosed in which the resist surface is activated by using the following sodium hydroxide or developer, and after development, the developer is neutralized with a dilute acidic solution.

This method activates the resist surface,
Although it can be expected to have some effect in terms of improving compatibility with water and preventing uneven development, the use of two types of processing solutions in addition to pure water and developer will only make operations more frequent. Moreover, consideration must be given to waste liquid treatment after using this treatment liquid, which not only increases the complexity of the process but also imposes a large economic burden.

(Effects of the Invention) Therefore, an object of the present invention is to provide a method for developing a positive photoresist that can prevent uneven development with a simple operation and eliminates frequent operations and economic waste. It's about doing.

(Means for Solving the Problems) The present invention has been proposed to achieve the above-mentioned object. This invention has a technical feature in that it prevents the occurrence of unevenness.

That is, according to the present invention, a substrate on which a positive photoresist layer is formed is subjected to (1) a pre-rinsing process using pure water, (2) a developing process using a developer, and (2) a development stop/cleaning process using pure water.

When carrying out wet development through a process consisting of A method for developing a patterned photoresist is provided.

According to the present invention, by controlling the supply timing of pure water and developer in each process,
Although it is possible to change a positive photoresist without uneven development, the supply of pure water in the pre-rinsing process is stopped 1 to 4 seconds after the start of supply of developer, and By controlling the process to occur 1 to 4 seconds after the start of water supply, an excellent effect of preventing uneven development can be achieved. When this is done, uneven development can be most effectively prevented.

(Description of preferred embodiments of the invention) As mentioned above, the technical feature of the present invention is that while the substrate is being rotated at high speed, pure water is first sprayed or showered uniformly from the center of the substrate to the outermost periphery. Then, while supplying pure water, the developer is supplied evenly from the center to the outermost part of the substrate from another spray or shower nozzle, and both are supplied simultaneously for several seconds. After that, the supply of pure water is stopped.

The rotation of the board needs to be done at high speed.

The zero rotation speed is preferably at least 1.00 rpm, preferably 120 to 1400 rpm.
If it is less than 100 Orp, the supply of the liquid on the substrate becomes uneven, which causes uneven development on the photoresist surface, which is not preferable.

■The supply of pure water, developer, and pure water for each of the pre-rinsing process, ■developing process, and ■developing stop process is ■0.5 to 2
．． Off/a+in, 10 to 60 seconds; ■100 to 500 cc/akin, 10 to 120 seconds;
(2) 0.5 to 2.5 Q, /n1in for 30 to 90 seconds, and the supply of both liquids is overlapped for 1 to 4 seconds, preferably 2 to 3 seconds in the transition stage of (2) to (2). Also in the transition stage from ■ to ■, the supply of both liquids is overlapped for 1 to 4 seconds, preferably 1 to 2 seconds.

In any stage, it is extremely important to supply both liquids in duplicate, and if the duplication supply time is outside the above range, suitable development will not be achieved.

In addition, it is desirable to supply the amount of pure water in the development stop step (■) that is at least three times the amount of the developing solution (■). If the supply of pure water (■) is too small, the development will not be stopped quickly and may result in overdevelopment. Therefore, uneven development is likely to occur.

(Example) Hereinafter, the present invention will be explained based on Examples.

Example 1 In FIG. 1, which shows a cross-sectional view of an example of a developing apparatus for developing a positive photoresist of the present invention, a positive photoresist 4 placed on a substrate l having a diameter of 220 mm is rotated on a turntable 5. By setting it to 1100 Drp, from the pure water feed nozzle at Ig/min for 10 seconds,
Pure water 2 was sprayed onto the entire surface of the photoresist, then developer 3 was applied at 250 ml/win.
The developer was supplied to the entire surface of the photoresist through a developer feed nozzle 7 using a one-way shower system. Stop supplying pure water 3 seconds after starting supply of developer, and continue supplying only developer for 20 minutes.
It went for seconds. Immediately before the supply of the developer was finished, pure water for cleaning was started to be supplied in an in/win manner, and then the supply of the developer was stopped. Pure water was used for washing for 60 seconds.

After the above steps are completed, the rotation speed of the turntable 5 is increased to 200 rpm, and N2 blowing is performed for about 60 seconds.
The substrate was allowed to dry.

It was confirmed that the positive photoresist thus obtained was developed without any uneven development over the entire surface.

Example 2 Supply of pure water in pre-rinsing process at 1.5127w1
n for 60 seconds, and supply the developer at 500 ml/lll1n.
The same procedure as in Example 1 was carried out, except that the supply of pure water in the cleaning step was 90 seconds at 2.0β/n+in, and the overlap supply time of both was 2 seconds. went. As a result, no unevenness was observed on the developed surface.

Comparative Example 1 In the pre-rinsing step, pure water was supplied at iI2/+in for 10 seconds, and at the same time as the supply of pure water was stopped, the supply of developer was started. Developing solution supply is 250ml/ll1in
141! for 20 seconds, and at the same time, the supply of pure water in the cleaning process is stopped. /ll1in and washed for 60 seconds.

The rotation speed of the turntable was the same as in Example 1.

As a result, irregular curved development unevenness, observed as a rainbow-like striped pattern, occurred in several places in the radial direction of the developed surface.

Comparative Example 2 The rotation speed of the turntable on the 1D floor was set to 80 Or
The same procedure as in Example 1 was carried out except that pm was used.

As a result, as in Comparative Example 1, irregular curved development unevenness of 11J occurred in several places.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of a developing device for developing a positive photoresist of the present invention. In the figure, 1 is a substrate, 2 is pure water, 3 is a developer, 4 is a photoresist, 5 is a turntable, 6 is a pure water feed nozzle, 7 is a developer feed nozzle, and 8 is a motor. Written amendment (spontaneous) November 6, 1990 Patent Application No. 2600 of 1999 Name of the invention Relationship with the case of a person amending the developing method of a positive photoresist Patent applicant's agent Address: 113 and above

Claims (1)

[Claims] (1) The substrate on which the positive photoresist layer is formed is subjected to (1) a pre-rinsing process using pure water, (2) a developing process using a developer, (3) a development stop/cleaning process using pure water. When carrying out wet development through the steps consisting of, the supply of pure water in the pre-rinsing step is stopped after the supply of the developer is started, and the supply of the developer is stopped after the supply of the cleaning pure water is started. How to develop positive photoresist. (2) The supply of pure water in the pre-rinsing process is stopped 1 to 4 seconds after the start of supply of developer, and the supply of one developer is stopped 1 to 4 seconds after the start of supply of cleaning pure water. The developing method according to claim (1), wherein the developing method comprises: (3) The developing method according to claim 1, wherein the developing is performed on a turntable rotating at a speed of at least 1,000 rpm.