JPH04155915A - Development of processed substrate - Google Patents

Abstract

PURPOSE:To prevent development and defects due to the residue by a method wherein after prerinsing a processed substrate or rensing the substrate following development, a developing cup is washed with a developing solution and the developing solution is newly supplied for development of the substrate after eliminating a rinsing solution through a first drain or the developing solution is supplied after the rinsing solution evaporates by itself. CONSTITUTION:An exposed processed substrate 3 is secured by suction to a spin chuck 2 of a developing machine. Using isopropyl alcohol(IPA) as a prerinsing solution, the spin chuck 2 is rotated. With an upper cup 5 being raised, methylisobutyl ketone(MIBK), a developing solution, is supplied through a developing solution inlet 7 of the upper cup 5 and IPA is eliminated through a first drain 10. Nextly, the spin chuck 2 and upper cup 5 are lowered. Then, MIBK is supplied through the developing solution inlet 7 of the upper cup 5 for developing the processed substrate 3. After that, the upper cup is lowered and MIBK is eliminated through the first drain 10. Thus, the development is finished.

Description

[Detailed Description of the Invention] [Summary] Regarding a method for developing a substrate to be processed, the purpose of the present invention is to eliminate uneven development and residue-based defects by using a developing cup of a developing machine that holds a developer and performs development with a developer. After cleaning, a developing solution is supplied again to perform development, or a developing solution is supplied after the rinsing solution remaining in the developing cup has evaporated, and development is performed. Configure the method.

[Industrial application field]

The present invention relates to a method for developing a substrate to be processed used for forming a semiconductor device.

Thin film formation technology, photolithography (photolithography or electron beam lithography), semiconductor layer formation technology, etc. are used to form semiconductor devices.

For this reason, photo-etching technology involves forming a resist layer by coating a substrate thinly with resist using a spin coating method or the like, and then selectively exposing the resist layer to ultraviolet rays or electron beams. A resist pattern is created by immersing the substrate in a developer and selectively etching the resist.

There are two types of resist: "negative type" in which the irradiated area is insoluble in the developer, and "positive type" in which the irradiated area is soluble in the developer.

After the development is completed, the substrate to be processed is cleaned using a rinsing liquid to prevent the resist pattern from swelling.

Here, the term "substrate to be processed" refers to a semiconductor wafer forming a semiconductor device, a mask substrate for performing projection exposure on the semiconductor wafer, a reticle forming the mask substrate, and the like.

[Conventional technology]

Developing a substrate to be processed is performed using a developing machine.

There are various types of developing machines, and although it is difficult to generalize, Figure 1 is a cross-sectional view of a single-fed dip developing machine used by the inventor. Explain how.

The developing machine has a spin chuck 2 in the center of the lower cup 1, which is rotated at high speed by a motor and has a vacuum suction function, so that it can vacuum suck the substrate 3 to be processed, and can slide up and down and is in contact with the rotating shaft. An O ring 4 is provided at the upper end of the lower cup 1, and a spin chuck 2
It is possible to seal hermetically in the event of a fall.

Further, on the lower cup l, an upper cup 5 that can be slid up and down or a ring shape is provided with the spin chuck 2 in the center, and a second drainage channel (hereinafter referred to as a second drain) 6 is provided in the center. It is equipped with a developing and liquid introduction lower.

In addition, there is a ○ ring 8 on the bottom surface of the upper cup 5.
When the upper cup 5 descends and comes into contact with the lower cup 1, an airtight seal is achieved, and a developing cup 9 for storing the developer is formed.

(The above corresponds to A and B in Figure 1) Next, after storing the developer in the developer cup 9, development is performed.
After that, to remove this developer, it is sufficient to raise the upper cup 5, and the developer is discharged through a first drainage channel (hereinafter referred to as first drain) 10 formed between it and the lower cup 1. .

(The above corresponds to C in the same figure) In the developing process, the substrate 3 to be processed is suctioned and fixed to the spin chuck 2 as shown in FIG. , the substrate 3 to be processed is cleaned by spraying a rinse liquid 12 from the spray nozzle 11 to remove dust adhering to the substrate 3 to be processed.

In this case, the rinse liquid 12 is scattered by centrifugal force and is discharged from the second drain 6 provided in the upper cup 5. (The above is A in the same figure) Next, the spin chuck 2 and the upper cup 5 are lowered, and the upper cup 5 is brought into contact with the lower cup l.
A developer is supplied from the developer introduction lower into the developer cup 9 until the substrate 3 to be processed is immersed, thereby performing development. (The above is B in the same figure) Next, after immersion for a predetermined time and development is completed, the upper cup 5 is raised, and the developer is discharged from the first drain 10.

(See Figure C) Next, raise the spin chuck 2 and lower the upper cup 5 to return it to its original position, rotate the spin chuck 2 with a motor, spray the rinse liquid 12 from the spray nozzle 11 to rinse it, and then spin the The rotation speed of the chuck 2 is increased to dry the substrate 3 to be processed.

The processing target substrate 3 was developed through such a process.

However, in the rinsing process performed after the substrate 3 to be processed is suctioned and fixed to the spin chuck 2 and the rinsing process performed after development, the rinsing liquid 12 is not completely discharged, and some of the rinsing liquid remains in the developing cup 9. was unavoidable.

[Invention or problem to be solved]

Single-wafer deep development is carried out using a developing machine.
It is carried out by taking the steps of brining → development → rinsing, or by taking the steps of development → rinsing.

However, since development processing is performed continuously, a portion of the previously used rinse liquid often remains in the developing cup, which causes uneven development, which is a problem.

[Means to solve the problem]

The above problem involved coating a resist on a substrate to be processed, selectively exposing the substrate to ultraviolet rays or electron beams, and then setting the substrate in a developing machine and immersing it in a developer to selectively etch the resist. In a developing method in which a resist pattern is obtained on a substrate to be processed by rinsing it afterwards, is it possible to wash the developing cup of a developing machine that holds a developing solution and performs development with a developing solution, and then supply the developing solution again to perform development? Alternatively, the problem can be solved by configuring a method for developing a substrate to be processed, characterized in that the developing solution is supplied after the rinsing solution remaining in the developing cup evaporates, and development is performed.

[Effect]

When substrates to be processed are continuously developed using a single-wafer type developing machine, some developer or rinsing solution remains in the developing cup of the developing machine.

In this case, there is no problem if the developing solution is left and the developing solution is supplied to this, but if the rinsing solution is left and the developing solution is supplied to this and the developing is carried out, the resist Since the solubility in the toner differs within and between the surfaces of the substrate to be processed, uneven development occurs on the substrate to be processed.

Furthermore, significant differences appear in development between substrates to be processed, resulting in a decrease in quality.

Therefore, in the present invention, after performing brining, or after rinsing after development if brining is not performed, the developing cup is washed with developer, the rinsing liquid is drained through the first drain, and then the developer is added again. supply it and develop it, or
Alternatively, wait for the rinsing liquid to evaporate before supplying the developer.
It is used for developing.

In this way, if development is performed with the rinse liquid removed, high-quality development can be achieved.

〔Example〕

A 5-inch square reticle dry plate made of quartz is used as the substrate to be processed.
After forming chromium (Cr) and chromium oxide (CrzOs) to a thickness of 700 and 300 mm on this substrate by sputtering, E, which is a positive resist for electron beams, was applied.
BR-9 was spin coded to a thickness of approximately 5000 people.

Then, set this substrate to be processed in an electron beam exposure device,
A pattern for LSI was selectively exposed.

Next, this substrate 3 to be processed was suctioned and fixed to a spin chuck 2 of a developing machine shown in FIG.

First, using isopropyl alcohol (abbreviated as IPA) as a rinsing liquid, dust was removed by spraying twice from the spray nozzle 11 at a rate of 70 CC/min for 10 seconds each while rotating the spin chuck 2 at 20 rpm. (The above corresponds to FIG. 1 A) Next, with the upper cup 5 raised, use methyl isobutyl ketone (abbreviated as MIBK) as a developer, and 5
00cc/min flow rate for 5 seconds, first drain 1
IPA was excluded through 0.

(This completes the brining process.) Next, after lowering the spin chuck 2 and the upper cup 5, 300 cc of MIBK is supplied from the developer introduction lower of the upper cup 5, which is provided at eight locations, to fill the developer cup 9. The substrate 3 to be processed was immersed and developed for 150 seconds. (The above corresponds to B in the figure) Next, the upper cup 5 was raised and MIBK was discharged through the first drain 10 to complete the development.

(The above corresponds to C in the same figure) Next, raise the spin chuck 2 and add IPA as a rinsing liquid.
With the spin chuck 2 rotating at 20 Orpm, IPA was sprayed from the spray nozzle 11 at a flow rate of 70 CC/min for 30 seconds for rinsing, and then the rotation speed was increased to 120 Orpm and held for 30 seconds. Dry. (The above corresponds to A in the same figure) The characteristics of the reticle dry plate thus formed were compared with those developed by a conventional method.

In other words, 100 mm in the center of a 5 inch square reticle board.
Five sheets each having 19×19 2 μm line and space test patterns formed on a mm square area were made, and the pattern width distribution, pattern width variation, and number of defects were compared.

In Table 1, 3σ is the average value of each 5 sheets, and it is 0.03 μm when the present invention is applied and the developer cup is cleaned with developer.
It has been improved.

Furthermore, MAX-NIN is a result of comparing the average value of five sheets with respect to the pattern width, and it is found that the pattern width is improved by 0.02 μm when the developing cup is cleaned with developer.

In addition, the number of defects is the number of residual defects after etching, and shows the average value for 5 substrates, and 0.6 is 3 defects in 5 substrates, or 1°8 This indicates that there were 9 defects.

By applying the present invention in this way, variations in pattern width are reduced and the number of defects is reduced.

〔Effect of the invention〕

By implementing the present invention, it is possible to reduce development unevenness and the number of defects when developing a substrate to be processed after selectively exposing a resist, thereby improving the quality of semiconductor device formation.

Note that this method can also be applied to etching apparatuses having a similar structure.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the developing machine for explaining the developing operation. In the figure, 1 is the lower cup, 2 is the spin chuck, and 3 is the lower cup.
1 is a substrate to be processed, 5 is an upper cup, 6 is a second drain, 7 is a developer inlet, 9 is a developer cup, 10 is a first drain, 11 is a spray nozzle, and 12 is a rinse liquid.

Claims (1)

[Claims] After a resist is coated on a substrate to be processed and the substrate is partially exposed by projection exposure or contact exposure, the substrate is set in a developing machine and immersed in a developer to process the above-described process. In a developing method in which the resist is selectively etched and then rinsed to obtain a resist pattern on the substrate to be processed, the developer cup of the developing machine that holds the developer and performs development is cleaned with the developer, and then the developer is supplied again. 1. A method for developing a substrate to be processed, characterized in that the development is carried out by using a developing cup, or by waiting for the evaporation of a rinsing liquid remaining in a developing cup and then supplying a developing solution.