JPH0781928A - Silicon dioxide coating film producing device - Google Patents

Abstract

PURPOSE:To reduce dust and obtain a silicon dioxide coating film by providing a pipeline to which filters with the pore diameter successively increased toward the downstream side are connected in series, a bypass pipeline, etc., in the filtration means of a circulating line of the specified device. CONSTITUTION:A processing soln. contg. silicon dioxide, etc., is filled in a treating tank 1 in which a substrate 3 to be treated is arranged, and a circulating means 5 and a filtration means 6 are provided between the tank 1 and a processing soln. regulating tank 4. A filter F1 (having a smaller pore diameter of 0.3mum) and a filter F2 (having a larger pore diameter of 0.5mum) are connected to the pipeline of a system 11 of the filtration means 6 in series toward the downstream side. A bypass pipeline 13 having a stop valve V1 is furnished to the filter F1 of the system 11 and to the filter F2 of a system 12 having the same constitution, and the system 11 or 12 is used by switching three-way valves V3 and V4. When the valve V1 is closed, the processing soln. is passed through the filters F1 and F2, and dust is blocked by the filter F1 in this silicon dioxide coating film producing device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silicon dioxide coating manufacturing apparatus, and more particularly, to a silicon wafer on a substrate to be processed such as a semiconductor wafer or a glass substrate in a semiconductor manufacturing process or a manufacturing process of electronic parts such as a liquid crystal display device. The present invention relates to an apparatus for producing a silicon dioxide film that produces a film from a liquid phase.

[0002]

2. Description of the Related Art A liquid phase film forming method (LP
Since the method D) can form a film at a temperature near room temperature and has a good followability even on a submicron level surface irregularity, a film with a uniform thickness and few defects can be obtained. There is. The liquid phase film forming method of this silicon dioxide film is
For example, JP-A-60-33233 and JP-A-62-2
It is proposed by Japanese Patent Publication No. 0876.

FIG. 4 is an explanatory view showing a device structure of a device for producing a silicon dioxide film by a liquid phase film forming method. The processing tank 1 is loaded with a semiconductor substrate or a glass substrate which is the substrate 3 to be processed, and is immersed in a processing liquid 2 containing a hydrosilicofluoric acid solution in a supersaturated state of silicon dioxide. , A silicon dioxide film is deposited. In the treatment liquid adjusting tank 4, the active material 7 such as aluminum is dissolved in order to maintain the supersaturated state of the silicon dioxide of the treatment liquid 2.

When a substrate 3 to be processed, for example, a semiconductor wafer is immersed in a treatment liquid 2 containing silicon dioxide in a supersaturated state and a silicon dioxide film is formed on the surface thereof, particles of silicon dioxide or the like precipitated in the treatment liquid 2. Grows and coarsens, and floats in the processing liquid 2 as so-called dust. Further, particles such as silicon dioxide are deposited in the treatment liquid 2 during film formation and adhere to the inner wall of the treatment tank 1, the inner wall of the pipe passage, the inner wall of the treatment liquid adjusting tank 4, and the like. As the film formation progresses, particles are further deposited on the particles attached to the wall surface, and the film of the particle layer attached to the wall surface gradually becomes thicker. When the particle layer adhering to the inner wall of the tank or the inner wall of the pipe is peeled off, it also becomes dust floating in the treatment liquid 2. This dust often adheres to the surface of the wafer and becomes a defect in the silicon dioxide film, often lowering the yield of semiconductor devices.

Therefore, in order to remove dust such as silicon dioxide particles in the treatment liquid 2, a circulation means 5 and a filtration means 6 are provided to circulate and filter the treatment liquid 2. The circulation means 5 has no pulsation and does not adversely affect the filtration.
Also, a centrifugal pump is used, which allows a relatively large circulation flow rate. As the filtering means, a filter having a pore size of about 0.2 to 1 μm is used. The filter usually has its pore size reduced from upstream to downstream. For example, the upstream filter F ₁
Has a pore size of 0.5 μm, and the downstream filter F ₂ has a pore size of about 0.3 μm. This is because, in order to prevent clogging of the final filter, it is common to arrange a filter having a hole diameter coarser than that of the final filter in the preceding stage (upstream side) thereof.

However, in the above-mentioned apparatus configuration for forming a silicon dioxide film from a liquid phase, the film forming rate is slow, and it takes a very long time to form a film at a film forming rate of, for example, 10 to 20 Å / min. Resulting in. When the film forming speed is low as described above, the inner wall of the tank or the inner wall of the conduit is considerably contaminated by the adhered particle layer of silicon dioxide and the like when the film forming process is performed once. For this reason, the filter is clogged and clogged during one film formation. Therefore, as shown in FIG. 4, two filters 11 and 12 are prepared and used by alternately switching. . That is, for example, the first system 11
When using the filters F ₁ , F ₂ of the three-way valve V ₁ ,
The treatment liquid is circulated and filtered by setting V ₃ to the circulation side 8. Meanwhile, the filters F ₁ and F ₂ of the second system 12 are cleaned. For cleaning the filters F ₁ and F _2, a cleaning solution such as hydrofluoric acid is introduced from the cleaning solution inlet A, and the three-way valve V ₂ and the filter F are used.
₁ and F ₂ are discharged from the three-way valve V ₄ to the cleaning liquid outlet B. Then, the filters F ₁ and F of the first system in use
_{If 2} is clogged and closed, three-way valves V ₂ , V ₄
Is switched to the side of the processing liquid circulation path 8 and the three-way valves V ₁ and V ₃ are switched to the cleaning liquid inlet A and the cleaning liquid outlet B side, respectively, and the processing liquid 2 is filtered by the cleaned filters F ₁ and F ₂ of the second system. Filtering, during which the filter F ₁ , of the first system 11
To clean the F _2.

[0007]

However, in the device configuration as described above, since the filter closing time is short,
It is necessary to switch the filter system at least 2-3 times during one film formation. At the time of this switching, it is necessary to switch the _three- way valves V ₃ and V ₄ on the secondary side of the filter. When the filter is clogged by the dust in the treatment liquid, a considerable amount of silicon dioxide particle layer coating is attached to the inner wall of the secondary side three-way valve. Then, when the three-way valve is switched, the coating of the particle layer adhering to the inner wall of the valve is peeled off, and dust is released into the processing liquid.

The present invention has been made in view of the above problems of the prior art, and extends the substantial blocking time of the filter,
An object of the present invention is to provide a device for manufacturing a silicon dioxide film, which is provided with a filtration means capable of switching filters during film formation without generating dust in the treatment liquid.

[0009]

SUMMARY OF THE INVENTION An apparatus for producing a silicon dioxide film according to the present invention comprises a treatment liquid containing a hydrosilicofluoric acid solution in which silicon dioxide is supersaturated, and the treatment liquid being brought into contact with a substrate to be treated. Processing tank for depositing a silicon dioxide film on the surface of the substrate, a processing solution adjusting tank for dissolving an active material to maintain a supersaturated state of the silicon dioxide of the processing solution, the processing solution, and the processing tank In the apparatus for producing a silicon dioxide film, which comprises a circulation means for circulating the liquid in the liquid adjusting tank and a filtration means arranged in a circulation path of the treatment liquid, the filtration means comprises:
A pipe in which a plurality of filters each having a larger pore size are connected in series from upstream to downstream, and a bypass pipe line having an on-off valve that bypasses each filter except the most downstream filter of the pipe is provided. Characterize.

[0010]

Since the filtering means is provided with a pipe in which a plurality of filters each having a larger pore size are connected from upstream to downstream and a bypass pipe line having an opening / closing valve for bypassing each filter, the filter of each pore size is provided. It is possible to circulate the treatment liquid by bypassing depending on the clogging situation. Therefore,
If you first close all the bypass valves of the bypass pipelines,
The treatment liquid is mainly circulated and filtered by the most upstream filter having the smallest pore size. When film formation progresses and the most upstream filter becomes clogged, the second filter from the upstream
The coating of the deposited particle layer reduces the substantial pore size. Here, the on-off valve of the bypass pipe line of the most upstream filter is opened to bypass the most upstream filter and circulate the processing liquid. At this time, the second filter from the upstream has substantially the same pore size as the pore size at the start of use of the most upstream filter (referred to as the minimum pore size), and the circulation of the treatment liquid is continued with the filter having the smallest pore size. can do.

By thus bypassing the clogged filters in sequence and circulating the treatment liquid, the blockage time due to the substantial clogging of the filters is extended according to the number of filters connected in series. be able to.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The first and second embodiments of the present invention will be described below with reference to the attached FIGS.

In these examples, a treatment tank 1 for depositing a silicon dioxide film on a substrate 3 to be treated from a treatment liquid 2 containing a hydrosilicofluoric acid solution in which silicon dioxide is supersaturated.
A treatment liquid adjusting tank 4 for dissolving the active material in order to maintain the supersaturated state of the treatment liquid silicon dioxide; and a circulation means 5 for circulating the treatment liquid between the treatment tank 1 and the treatment liquid adjusting tank 4.
It is the same as the conventional technique in that the filter means 6 is provided in the circulation path of the treatment liquid.

FIG. 1 shows the construction of the filtering means of the first embodiment of the present invention. In the pipe of the first system 11, two filters F ₁ and F ₂ having large pore diameters are sequentially connected in series from upstream to downstream. In this embodiment, the upstream filter F
₁ has a pore size of 0.3 μm (minimum pore size), and the downstream filter F ₂ has a pore size of 0.5 μm. Except for the filter F ₂ which is the most downstream filter, the filters F ₁ connected in series have a bypass pipe line 13 equipped with an on-off valve V ₁ . The second filter system 12 also has the same configuration as the first filter system 11. First filter system 1
The first and second filter systems 12 can be switched and used by _three- way valves V ₃ and V ₄ .

Next, the operation of this filtering means will be described. At the start of film formation on the substrate 3 to be processed, the filter system 11
Was used. At the start of film formation, the valve V ₁ of the bypass pipe line 13 is closed. Therefore, the treatment liquid is circulated and filtered through the filter F ₁ having a minimum pore diameter of 0.3 μm and the filter F ₂ having a pore diameter of 0.5 μm. Upstream, the small filter F ₁ of the pore diameter is disposed, the minimum hole diameter or on the particles (dust) are blocked by the filter F _1, particles smaller than the pore size of the filter F ₁ (dust) on the downstream Flowing. As the film formation progresses, the filter F
Particles of silicon dioxide deposited in the treatment liquid adhere to ₁ and F _2, and the coating of the particle layer gradually thickens.

FIG. 2 shows the particle layer deposited in the pores of the filter, and (A) shows the pores of the filter having a thickness of 0.5 μm immediately after washing. As the treatment liquid circulates and passes through the pores of the filter, particles of silicon dioxide deposited in the treatment liquid adhere to the pores, and the coating 15 of the particle layer gradually grows. In this way, as shown in (B), the initial pore size of the filter was 0.5 μm, but it decreased to about 0.3 μm as the film formation progressed.

Therefore, the filter F ₁ of the first system had a diameter of 0.3 μm (minimum pore size) at the start of film formation, but the actual pore size becomes about 0.2 μm as the film formation progresses.
At this time, the pore size of the filter F ₂ on the downstream side was about 0.5 μm at the start of film formation, but it was substantially reduced to about 0.3 μm. When the filters are connected in series, the circulating amount of the treatment liquid is limited by the filter having the smallest pore size, so that the pore size of the filter F ₁ is substantially 0.2 μm.
When the amount becomes small, the circulating amount of the processing liquid is reduced, and the film forming speed is reduced. Therefore, at this time, the bypass pipeline 1
The on-off valve V ₁ of _No. 3 is opened. Then, most of the processing liquid flows through the bypass pipe line 13, flows through the filter F ₂ , and is substantially circulated and filtered by the filter F ₂ . At this time, since the pore size of the filter F ₂ is substantially about 0.3 μm (minimum pore size), the minimum pore size for circulating filtration is the same as that at the time of film formation start.

By bypassing the blocked filter F ₁ , the substantial closing time of the filter system 11 is substantially the same as the time when the filter F ₁ is closed, and the filter F ₂ has a substantial pore diameter of 0.3 μm or more. 0.2 μm pore size
It can be extended until the time becomes small. Therefore, as compared with the conventional case where the filter F ₁ having a pore diameter of about 0.3 μm is used as the most downstream filter, the substantial blocking time can be extended to about twice. In this way, according to the filtering means of the present embodiment, it is possible to double the blocking time of the filter while maintaining the filtering hole diameter of the conventional final filter.

FIG. 3 shows the filter means of the second embodiment of the present invention.
The configuration is shown. In this embodiment, from upstream to downstream
Three filters F with large pore size ₁ , F₂ , F₃ Straight
It has piping connected to the rows. The pore size of the filter is
Upstream filter F₁ Is 0.3 μm, and the next fill
Ta F₂ Has a pore size of 0.5 μm, and is the most downstream filter F.₃ 
Is 0.8 μm. Downstream filter F₃ Except each
The on-off valve V₁ , V₂ By-pass pipeline 1
It has 3,14.

The operation of this embodiment is similar to that of the first embodiment. That is, at the start of film formation, the on-off valve V ₁ ,
V ₂ is closed, and particles (dust) in the treatment liquid are mainly circulated and filtered by the filter F ₁ having the smallest pore size.
When the filter F ₁ becomes clogged with the progress of film formation, the valve V ₁ is opened and the processing liquid is allowed to flow into the bypass pipe line 13.
At this time, the next filter F ₂ has a pore size of 0.5 μm
It is substantially reduced from m to about 0.3 μm (minimum pore size). Therefore, even after the filter F ₁ is closed, the treatment liquid can be circulated and filtered by using the filter having the same minimum pore size as that at the beginning of the film formation. When the film formation on the substrate 3 to be processed further progresses and the filter F ₂ becomes clogged, the valve V ₂ is opened, the processing liquid is caused to flow into the bypass pipe line 14, and the processing liquid is circulated mainly through the most downstream filter F _3. Filter. The filter F ₃ had a pore size of 0.8 μm at the start of film formation.
However, when the filter F ₁ becomes clogged, the actual pore size becomes about 0.5 μm,
When the filter F ₂ is clogged, the actual pore diameter is about 0.3 μm (minimum pore diameter).
In this way, while maintaining the minimum pore diameter of 0.3 μm,
The effective blocking time of the filter system can be tripled.

[0021]

As described above, according to the filtering means of the present invention, by sequentially bypassing the filters connected in series, it is possible to greatly extend the blocking time of the filters, and it is possible to increase the blocking time of one time. It becomes possible to perform the membrane treatment without switching the filter system. Further, since the filter closing time is extended, it is possible to employ a filter having a small hole diameter. Thereby, the amount of dust existing in the treatment liquid can be further reduced, and a high-quality silicon dioxide film can be formed. Furthermore, since the filter closing time is extended, the degree of supersaturation of silicon dioxide in the processing liquid can be increased to shorten the required film forming time.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a device configuration of a silicon dioxide film manufacturing apparatus according to a first embodiment of the present invention.

2A and 2B are explanatory views showing that a film of a particle layer grows in a filter hole portion, FIG. 2A shows a pore diameter at the start of film formation, and FIG. Shows a state in which the pores have grown and the pore size has become substantially smaller.

FIG. 3 is an explanatory diagram showing a device configuration of a silicon dioxide film manufacturing apparatus according to a second embodiment of the present invention.

FIG. 4 is an explanatory view showing a device configuration of a conventional silicon dioxide film manufacturing apparatus.

[Explanation of symbols]

1 processing tank 2 processing liquid 3 substrate to be processed 4 processing liquid adjusting tank 5 circulating means 6 filtering means 8 main circulation path 11, 12 filter system 13, 14 bypass piping paths F ₁ , F ₂ , F ₃ filter V ₁ , V ₂ Open / close valve

Claims (1)

[Claims] 1. A treatment solution containing a hydrosilicofluoric acid solution in which silicon dioxide is supersaturated, and a treatment tank for bringing the treatment solution into contact with a substrate to be treated to deposit a silicon dioxide film on the surface of the substrate. A treatment liquid adjusting tank for dissolving an active material in order to maintain the supersaturated state of silicon dioxide in the treatment liquid, a circulation means for circulating the treatment liquid between the treatment tank and the treatment liquid adjusting tank, and circulation of the treatment liquid In the apparatus for producing a silicon dioxide film, which comprises a filtering means arranged in a passage, the filtering means comprises a pipe in which a plurality of filters each having a larger pore size are connected in series from upstream to downstream, and the most downstream of the pipe. And a bypass pipe line provided with an on-off valve that bypasses each of the filters except the above filter.