JPH086260A - Method for developing resist and device therefor - Google Patents

Abstract

PURPOSE:To eliminate the defect of formation of the part remaining without being developed which is generated by the air bubble sticking to a resist film surface as a result of bubble inclusion, etc., at the time of dropping a developer to a substrate to be treated in resist development used for semiconductor production or color filter production, etc. CONSTITUTION:This device has a rotary chuck 7 which attracts the substrate 1 to be treated by vacuum and rotates the substrate, a vacuum deaerator 12 which forms deaerated pure water by vacuum deaeration of the pure water, a deaerated pure water dropping nozzle 13 which forms a liquid build-up by dropping the deaerated pure water onto the resist film 2 of the substrate 1 to be treated and a developer dropping nozzle 4 which substitutes the deaerated pure water build-up 14 with the developer. This method for developing the resist comprises forming the deaerated pure water build-up on the substrate l to be treated prior to development of the resist film and absorbing the air bubble sticking onto the resist film to the deaerated pure water, then substituting the deaerated pure water with the developer without bringing the pure water into contact with the air.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for developing a resist such as a semiconductor substrate and a color filter, and more particularly to a method and apparatus for developing a resist used for manufacturing semiconductors, color filters and the like.

[0002]

2. Description of the Related Art Conventionally, in the development in photolithography for manufacturing semiconductors and the like, Japanese Patent Application Laid-Open No. 4-260043 and JP-A-4-260043 have been proposed as a technique for preventing development residual defects due to minute bubbles adhering to the surface of a semiconductor wafer when developing droplets are dropped. Kaihei 3-266418 has been proposed. These conventional techniques will be described with reference to FIGS.

To form the resist pattern shown in FIG. 4, a soluble film (3) which is soluble in a developing solution such as polyvinyl alcohol is previously rotated on the surface of the resist film (2) on the substrate (1) to be processed. Nozzle (4) under the developing liquid drop
In this method, the developing solution (5) is dropped to form a developing solution heap (6) and the developing treatment is performed. The rotary chuck (7) in FIG. 4 holds the substrate (1) to be processed by suction and rotates it.

This prior art is characterized in that a soluble film (3) is applied to the surface of the resist film (2) in advance, which is a method in which a developing solution (5) is applied to a substrate (1) to be processed. This is to prevent air bubbles from directly adhering to the resist film (2) when supplied. Further, even if bubbles adhere to the soluble film (3), the developing solution (5) permeates while melting the soluble film (3),
As the development progresses, the bubbles rise up, and it is possible to prevent the undeveloped portion, that is, the development defect due to the bubbles during the development from occurring.

Next, another conventional technique will be described with reference to FIG.
Will be described. This is because before the resist film (2) on the substrate (1) to be processed is developed, pure water (9) or the like is discharged from a rinse nozzle (8) used for cleaning the substrate to be processed after development, to be processed. The resist film (2) which is the surface to be developed of the substrate (1) is uniformly covered with pure water (9) to be pre-wet, and then the substrate (1) to be processed is rotated so that the pure water (9) becomes a resist. This is a method in which the film (2) is shaken off to such an extent that the film is wet, and then a developing solution is dropped from a nozzle (4) below the developing solution droplets to form a developing solution puddle and a developing process is performed.

Pre-wetting with pure water or the like in the prior art of FIG. 5 is to prevent bubbles from adhering to the resist film (2) during the supply of the developing solution, as in the prior art of FIG. In this method, the substrate to be processed (2)
Is pre-wet with pure water before development processing,
Generally, the resist film (2), which has a strong tendency to be hydrophobic, can be made hydrophilic to some extent, and the developing solution (5) and the resist film (2) are well compatible with each other, so that air bubbles adhere to the resist film (2). It becomes difficult.

This developing method is generally used for TM in semiconductor manufacturing and the like.
Although it is carried out in a developing process using a developing solution of an alkaline aqueous solution such as AH, the method is disclosed in JP-A-3-266418.
In the developing method using an organic solvent such as an electron beam resist as in the "resist developing method", the pre-wetting liquid is used as a low developing solvent under limited conditions.

Further, the above-mentioned prior-art pre-wetting method tends to reduce development defects due to air bubbles, but cannot sufficiently bring about the effect. As a specific example, in the development process using an alkaline developer and TMAH on a 6-inch semiconductor substrate, the number of defects when the pre-wetting method is not used is 2-3 per substrate, and when the pre-wet formulation is used, the number of defects is per substrate. About 1 to 2 are generated.

[0009]

In the prior art shown in FIG. 4, the above-mentioned problems of the prior art are as follows. First, after the resist is applied to the substrate to be processed and the resist is exposed, that is, immediately before the developing process, the substrate is processed. Since a film soluble in a developing solution such as polyvinyl alcohol must be formed on the upper surface by spin coating, a coating cup and a chemical solution pipe for spin coating are required.

For example, in order to realize this in an actual production line of semiconductors or the like, the following three examples can be considered based on the above. That is, in the first example, the soluble film coating device is newly installed as a single unit. In the second example, a soluble film coating unit is added to the developing device. In the third example, a soluble solution discharge nozzle is added to the developing cup of the developing device, and the developing cup is also changed to a shape capable of applying a soluble film.

In common with the above-mentioned examples, in operation, management of the chemical solution itself of the soluble solution, particle management of the substrate to be processed after coating, uniformity of coating film, chemical solution replacement work, coating cup replacement The point is that the number of management items and work such as cleaning work will increase. In addition, it is also necessary to upgrade relatively large-scale facilities. Therefore, there are problems that a new load is applied to the work loading and that a relatively large amount of cost is required to renew the equipment.

Next, regarding the problem in the conventional technique shown in FIG. 5, in this conventional technique, the resist film surface of the substrate to be treated is pre-wet with pure water or the like in advance to make it hydrophilic so that the resist film surface is kept under the development droplet. However, even if this method is used, in the actual development process of semiconductor manufacturing, the development defects due to the bubbles are slightly reduced, but one defect is generated for each semiconductor substrate. Experimental results show that some defects occur. Therefore, there is a problem that development defects due to bubbles cannot be completely eliminated even by using the conventional technique of FIG.

[0013]

The present invention provides a semiconductor substrate,
In a method of developing a resist such as a color filter, before developing an exposed resist film on a substrate to be processed, degassed degassed pure water is dropped onto the substrate to be processed to obtain a degassed pure water solution. It is a resist developing method characterized by forming a heap, and the substrate to be processed is rotated while dropping the developing solution on the formed degassed pure water solution heap to form a degassed pure water solution heap. The resist developing method is characterized in that development processing is performed by substituting with a developing solution. In addition, a rotary chuck for adsorbing and rotating the substrate to be processed, a vacuum degassing mechanism for degassing pure water by vacuum to generate degassed pure water, and dropping degassed pure water on the resist film of the substrate to be processed. A resist developing apparatus, comprising: a degassed pure water dropping nozzle for forming a liquid pool and a developing liquid drop nozzle for replacing the degassed pure water liquid pool with a developing solution.

[0014]

In the present invention, before developing the resist film,
A degassed deionized water solution is formed on the substrate to be processed, the bubbles adhering to the resist film are absorbed by the degassed deionized water, and the degassed deionized water is replaced with a developer without touching the air. It has an effect of eliminating the undeveloped portion on the resist film and the occurrence of development defects. Although oxygen in the atmosphere is considerably dissolved in water, a natural oxide film is easily formed in pure water used for semiconductor substrates, color filters, etc.
Dissolved oxygen is removed because problems tend to occur. The method is to blow nitrogen gas into pure water and bubble it to expel dissolved oxygen. For this reason, nitrogen is usually dissolved in pure water, and no more gas can be taken into pure water. Therefore,
By degassing this in a vacuum, pure water can newly dissolve the gas and has the effect of absorbing the bubbles adhering to the resist film.

[0015]

Next, an embodiment of the present invention will be described with reference to the drawings. [Embodiment 1] FIG. 1 shows a first embodiment. In the resist developing method of this embodiment, first, a vacuum pipe (10) and a pure water supply pipe (11) are provided as an example of a pure water degassing method on a substrate (1) to be processed that is suction-held on a rotary chuck (7). Using a vacuum deaerator (12) equipped with, the deaerated pure water that has been vacuum deaerated by being exposed to a vacuum at a degree of vacuum of about 600 mmHg for 5 minutes or more is dropped from the deaerated pure water dropping nozzle (13) and deaerated. A pure water puddle (14) is formed.

At this time, the substrate (1) to be processed is rotated at a high speed of about 2000 rpm while dripping deaerated pure water, and the rotational speed is gradually reduced to form a degassed pure water puddle (14). .
The reason is that when the substrate (1) to be processed is kept stationary and degassed pure water is dropped, air bubbles easily adhere to the resist film (2) due to the entrainment of air. That is, when degassed pure water is dropped while the substrate (1) to be processed is rotated at high speed, the adhered bubbles are scattered with the degassed pure water to the outside of the substrate due to the centrifugal force, so that the bubbles remaining on the resist film (2) are removed. The number will be very small.

Generally, the size of the bubbles adhering to the resist film when the developing solution is dropped directly onto the resist film is about 10 μm to 100 depending on the size of the undeveloped portion which is a development defect.
It is estimated to be about μm. In the case of pure water, the size of bubbles is considered to be almost the same. Here, the bubbles remaining on the resist film (2) in the degassed pure water are about 2 minutes if they are bubbles of about 100 μm due to the substrate suction action of the degassed pure water having a high substrate absorbability. It became clear as a result of the following experiment that it disappears.

FIG. 3 is a diagram showing the experimental apparatus. About 10cc of pure water (16) in the transparent Teflon tube (15)
Is enclosed and is connected to an air-conbum type vacuum generator (19) through a joint (17) and a suction pipe (18). A vacuum gauge (20) for measuring the ultimate vacuum in the transparent Teflon tube (15) is connected to the joint (17).

The experiment was conducted by the following method. First, Fig. 3
When the vacuum generator (19) is operated in this state, the pure water (16) in the transparent Teflon tube (15) is degassed and bubbles (21) are generated by degassing. Vacuum gauge (20) at this time
Was 620 mmHg, and it was left for 10 minutes in that state. Next, with the deaeration completed, a transparent Teflon tube (15)
A small impact is applied to the inner surface of the Teflon tube to remove the bubbles (21) caused by defoaming, and the transparent Teflon tube (15) is divided by the dividing section (22).

Using the degassed pure water in the Teflon tube (15) as a sample, the absorption time of bubbles was measured by the following method. The bubbles are made visible by blowing air into the surface of degassed pure water with a syringe and a needle (not shown) and attaching them to the inner wall of the transparent Teflon tube (15). The bubbles to be observed are bubbles adhering within a depth of 1 mm to 3 mm from the surface of degassed pure water in contact with the air layer (23), which is close to the state of bubbles adhering to the resist film in the actual development process. The size selected was about 100 μm by visual inspection.

When the disappearance time of bubbles on the inner wall of the transparent Teflon tube (15) was measured 10 times by the above method, the average time was about 120 seconds. Regarding the deaeration time, it was confirmed that the same results as in this experiment could be obtained by performing deaeration for 5 minutes or more prior to the experiment. From the above experimental results, it was found that the bubbles with a size of 100 μm or less disappeared in degassed pure water within about 2 minutes.

Therefore, the bubbles remaining on the resist film (2) in the degassed pure water solution pool (12) on the substrate (1) to be processed are absorbed by the degassed pure water within about 2 minutes and disappear. It can be analogized. In this case, when the substrate (1) on which the degassed pure water solution (12) is placed is rotated or stopped at a low speed, the degassed pure water moves, so that the bubbles are degassed. It is presumed that the water is easily absorbed by pure water, and the bubble disappearance time becomes shorter than 2 minutes.

Now, let us return to the first embodiment. The degassed pure water solution puddle (14) is formed on the substrate (1) to be processed and left for about 2 minutes to eliminate the bubbles on the resist film (2), and then the following developing process is started. The substrate (1) to be processed is rotated while dropping the developing solution onto the central portion of the substrate (1) to be processed from the nozzle (13) for developing liquid drops onto the degassed pure water solution pool (14).

By this operation, the degassed pure water solution puddle (14) on the substrate (1) to be processed is replaced with the developing solution. In the replacement operation, the substrate (1) to be processed is rotated at a rotation speed such that the surface of the resist film (2) does not come into contact with the atmosphere. Further, the flow rate of the developing solution dropped from the developing liquid drop nozzle (4) is also relatively increased, the flow rate is suppressed, and the dropping operation is performed so that bubbles are not mixed by the dropping. By the above operation,
The degassed pure water solution pool (14) is replaced with a developing solution, the developing solution pool is formed on the substrate (1) to be processed, and the substrate is left for about 1 minute for development. Then, pure water or the like is discharged from the rinse nozzle (8) while rotating the substrate (1) to be processed, and after cleaning, the substrate (1) to be processed is rotationally dried to complete all development processing. To do.

As described above, in this embodiment, the bubbles adhering to the resist film (2) during the formation of the degassed pure water solution pool (14) are absorbed by the degassed pure water, and the developer is degassed pure water. Bubbles are not present on the resist film (2) because the liquid is dropped onto the puddle (14) and replaced. Therefore,
Undeveloped resist film due to air bubbles, that is, development defects, can be eliminated without the burden of relatively large-scale facility renewal or new operational management.

[Second Embodiment] FIG. 2 is a diagram showing a second embodiment. In the resist developing method of the first embodiment, the developing solution is dripped from the developing liquid drop nozzle (4) to the center of the substrate (1) to be processed until the degassed pure water solution pile (14) is replaced with the developing solution. Since the process is continued, the development in the vicinity of the central portion of the substrate (1) to be processed proceeds faster than in the other portions. For example, in the case of a semiconductor substrate pattern, the pattern line width in the vicinity of the central portion becomes narrower than the other portions. Tends to. In order to improve the problems as described above, in the second embodiment, a plurality of developing liquid drop nozzles (4) are provided and arranged on the center line of the surface of the substrate (1) to be processed.

The operation and developing process of this embodiment are exactly the same as those of the first embodiment. However, the developing liquid drop operation from the developing liquid drop nozzle (4) in this embodiment has the same dropping timing in all the nozzles, but the following measures are required. That is, since the flow rate of the developing solution per unit area of the substrate surface of each developing liquid drop nozzle (4) varies due to the rotation operation of the substrate to be processed (1), the developing solution flow rate of each developing liquid drop nozzle (4). The number of nozzles in the central portion of the substrate (1) to be processed is the smallest, and the number of nozzles in the outermost peripheral portion is the largest, that is, it is necessary to gradually increase the flow rate of the developing solution as the nozzles move to the outer peripheral portion. By doing so, the developing solution is evenly dropped on the substrate 1 to be processed, so that a more uniform developing pattern can be obtained.

[0028]

As described above, according to the present invention, a degassed pure water solution puddle is formed on a substrate to be processed before the resist film is developed, and bubbles adhering to the resist film are purely degassed. After being absorbed in water, the degassed pure water is replaced with the developing solution without touching the air, so that bubbles remaining on the resist film can be eliminated. Therefore, it has an effect that an undeveloped portion on the resist film, that is, a development defect caused by adhesion of bubbles is eliminated. Further, according to the present invention,
This has the advantage that development defects can be eliminated without the burden of relatively large-scale facility renewal and new operational management.

[Brief description of drawings]

FIG. 1 is a diagram showing a resist developing method according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a resist developing method according to a second embodiment of the present invention.

FIG. 3 is a diagram showing an experimental apparatus in a bubble absorption experiment of degassed pure water.

FIG. 4 is a diagram showing a resist developing method in a first known example of the related art.

FIG. 5 is a diagram showing a resist developing method in a second known example of the related art.

[Explanation of symbols]

 1 substrate to be processed 2 resist film 3 soluble film 4 developing liquid drop nozzle 5 developing solution 6 developing solution solution 7 rotating chuck 8 rinse nozzle 9 pure water 10 vacuum piping 11 pure water supply piping 12 vacuum deaerator 13 degassing pure Water dripping nozzle 14 Degassed pure water liquid fill 15 Transparent Teflon pipe 16 Pure water 17 Joint 18 Suction piping 19 Vacuum generator 20 Vacuum gauge 21 Bubbles due to defoaming 22 Dividing part 23 Air layer

Claims (3)

[Claims] 1. In a method of developing a resist for a semiconductor substrate, a color filter, etc., before developing an exposed resist film on a substrate to be processed, deaerated pure water deaerated on the substrate to be processed is treated. A method for developing a resist, which comprises dripping and forming a degassed pure water puddle. 2. The development treatment is performed by rotating the substrate to be processed while dropping a developing solution on the formed degassed pure water solution puddle and replacing the degassed pure water solution puddle with the developing solution. The resist developing method according to claim 1, wherein the resist developing method is used. 3. A rotary chuck for adsorbing and rotating a substrate to be processed, a vacuum degassing mechanism for degassing pure water by vacuum to generate degassed pure water, and a degassing pure on the resist film of the substrate to be processed. A resist developing device comprising: a degassed pure water dropping nozzle for dropping water to form a liquid puddle, and a developing liquid drop lower nozzle for replacing the degassed pure water liquid puddle with a developing solution.