JP2001340817A - Removal method and removal apparatus of pollutant adhering to surface - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a safe and efficient method for removing pollutants adhering to a surface which is capable of treating pollutants adhering to surfaces of a variety of articles such as substrates of electronic devices, e.g. semiconductor substrates, glass substrates for liquid crystals within a short time to remove the pollutants and clean the surfaces. SOLUTION: A treatment liquid produced by dissolving ozone in an organic solvent having 0.6 or higher distribution coefficient to ozone in gas phase is brought into contact with the surface of an object to be treated to which pollutants adhere to remove the pollutants adhering to the surface of the object to be treated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cleaning articles requiring removal of contaminants, and more particularly to a method for cleaning substrates for electronic devices. More specifically, the present invention relates to the removal of an organic film such as a photoresist used for processing a semiconductor wafer or a liquid crystal substrate, and cleaning of organic contamination generated throughout the wafer process. . More broadly, the present invention relates to cleaning organic contamination of precision metal and glass workpieces.

[0002]

2. Description of the Related Art Removal of a photoresist used for microfabrication on an oxide film or a polysilicon film usually involves a mixture of sulfuric acid (3 volumes or 4 volumes) and hydrogen peroxide (1 volume) (called piranha). And heat to 110-140 ° C for 1
A method of soaking for 0 to 20 minutes is used. When high-concentration ion implantation is performed with a resist mask, the resist deteriorates and cannot be removed by piranha treatment, and ashing with plasma-excited oxygen is widely used.
However, ashing all of the photoresist leaves trace metal from the resist on the wafer surface and harmful devices to the wafer surface due to the high energy plasma. Therefore, ashing is performed while leaving the resist film, and thereafter, the resist is removed by piranha treatment. Attempts have been made to mix ozone instead of hydrogen peroxide in this piranha treatment, but due to the low solubility of ozone, removal requires a longer treatment,
Hardly used.

Recently, a resist removal method using ozone water has appeared. The solubility of ozone in water increases as the temperature decreases, and the amount of dissolved ozone reaches 70 to 100 ppm in ultrapure water at about 5 ° C. When the resist is removed with such low-temperature and high-concentration ozone water, a 800-nm-thick positive-type novolak resin-based photoresist film widely used in LSI manufacturing can be stripped in about 10 to 15 minutes. (Peel rate 70 ~
80 nm / min). Organic substances such as dioctyl phthalate (DOP), siloxanes, and hexamethyldisilazane (HMDS) contaminate the surfaces of silicon wafers and oxide films from the atmosphere in a clean room for manufacturing semiconductor devices, which degrades device characteristics. It is known that the device yield is reduced.

As a wet cleaning method for removing organic substances on a silicon wafer or an oxide film, the above-mentioned piranha treatment has been most effective. However, SO ₄ ²⁻ remains on the wafer and generates fine particles under the influence of the environmental atmosphere, and tends to cause haze. To remove this completely, usually SC-1 treatment (standard composition _{NH 4 OH: H 2 O 2} : H 2 O = 1 volume: 1
Volume: 5 volume). The SC-1 treatment alone has the effect of decomposing and removing organic substances, and the effect of removing fine particles has conventionally been considered to be the most effective. However, in SC-1, Fe, Al, Ca, Mg, Z
n, Ni, etc. are easily deposited on the wafer during cleaning, and it is difficult to control the cleanliness of the chemical and the cleaning tank. So rare HF SC-1
Except for the chemical oxide film generated by the treatment, SC-2 treatment (standard composition is HC
1: H ₂ O ₂ : H ₂ O = 1 volume: 1 volume: 6 volume) is a conventional means of semiconductor cleaning, and is called an RCA method. In order to remove the surface residual SO ₄ ^2- , a technique of performing a large amount of rinsing with heated water for a long time is also used, but the achievable cleanliness is poor when the RCA method is usually followed.

[0005] As a cleaning method for organically contaminated wafers, the conventional treatment relying on piranha treatment is not satisfactory in terms of economy, productivity and safety. Ozone water has emerged as a new cleaning method to solve these problems. Ozone water is 20-30 at room temperature
Since ppm is obtained, it is intended to remove organic contamination of the wafer by this oxidizing power.

[0006]

With the advancement of semiconductor devices, especially VLSI, reduction of organic contamination on the wafer surface is becoming more and more important. Until recently, the roadmap published by the Semiconductor Industry Association of America did not mention surface organic carbon concentrations. Although published at the end of 1997, an organic carbon concentration of 1 × 10 ¹⁴ atoms / cm ² was allowed, but in 2009, this concentration required 1.8 × 10 ¹³ atoms / cm ² . This cleanliness is, of course, necessary even after the resist is peeled off. The piranha cleaning liquid is repeatedly used in terms of economy, but if the methyl silicon layer on the oxide film generated by the positive resist adhesive HMDS is to be removed to such a high cleanliness level, the piranha cleaning liquid deteriorated by repeated use. Then it becomes difficult, so the number of uses must be severely limited. Therefore, the use amount of sulfuric acid increases, which not only deteriorates the economic efficiency but also complicates wastewater treatment. In addition, since the removal of the resist on the metal film is damaged by a strong acid treatment, the film is damaged by using N-methylpyrrolidone (NMP) as a remover at about 70 ° C.
Minute dissolution treatment has been performed. In this case, ultrapure water rinsing is performed after rinsing with an organic solvent such as isopropyl alcohol. This treatment requires a large amount of an organic solvent, is not desirable in terms of economy, and is expensive in wastewater treatment.

Therefore, although ozone water treatment is expected, semiconductor-grade high-purity ozone water is produced by absorbing high-purity gas containing ozone into ultrapure water. By the way, when a gas containing ozone is injected into a container containing a liquid, the concentration of ozone in the gas is C _G [mg / L], and the concentration of ozone in the saturated liquid is C _L [mg / L]. When, the distribution coefficient D = C _L / C _G. Here, when the liquid is water, in one research example, the value of D is 0.2 at 25 ° C, the value of D is 0.28 at 20 ° C, and the value of D is 0.47 at 5 ° C.
The ozone concentration obtained with a normal high-purity ozone gas generator is about 200 mg / L,
The saturation concentration is 40 ppm at 5 ° C. and 94 ppm at 5 ° C. In practice, only a concentration slightly lower than this concentration can be obtained as described above. Moreover, ozone is easily decomposed in water, and the ozone concentration in the ozone water cleaning tank cannot be maintained at the highest level unless ozone gas is constantly circulated and ozone gas is injected. Further, if there is an obstacle to the flow such as a wafer carrier in the cleaning tank, a portion where ozone is insufficient on the wafer surface is formed, and the resist peeling speed is reduced. Even if the stripping speed of the resist itself has a value of about 100 nm / min, in order to completely remove all the wafers in the wafer carrier up to the methyl silicon layer, twice the processing time calculated from the stripping speed. Need more. That is, the removal of the resist film having a thickness of 1 μm takes 20 to 30 minutes.
Takes minutes.

According to the present invention, the immersion type resist stripping including the complete removal of the resist adhesive can be shortened, and the carbon content of the surface after the treatment can be reduced to the order of 10 ¹² atoms / cm ² . An object of the present invention is to provide a cleaning method which is also effective as a photoresist removing method.

Organic substances detected in the largest amount on a wafer in a semiconductor clean room are usually DOP.
The amount often exceeds 200 ng on the surface of the 6 ″ wafer. This DOP forms a fine spot-like oil film on the wafer surface, and the contaminating fine particles adhered to the surface are strongly adhered to the surface by the liquid crosslinking of the oil film. It is trapped and difficult to remove by cleaning, a phenomenon that can be significantly more significant on the backside of the wafer than on the frontside, because the backside of the wafer must be held in the device manufacturing process like a vacuum chuck. Because the surface of the material is usually lipophilic, it is contaminated by DOP or the like, and is transferred.In the semiconductor device manufacturing process, the back surface of the wafer is the front surface of the adjacent wafer. Face to face,
In some cases, a large number of sheets are processed at the same time, and at this time, the influence of organic substance contamination and fine particle contamination on the back side reaches the device forming surface to be faced. It is known that the contamination by DOP or the like hinders the removal of metal contamination in the cleaning process, and the adverse effects caused by the backside include metal contamination.

Accordingly, the present invention also provides a method of cleaning a substrate surface capable of strongly removing contaminant contaminants on the front and back surfaces of a wafer and removing contaminant metals. Further, since this organic contamination removal is extremely powerful and the pollution to the environment can be easily controlled, the present invention provides a cleaning method applicable to cleaning bodies other than electronic device substrates.

[0011]

To attain this object, the present invention firstly comprises dissolving ozone in an organic solvent having a distribution coefficient of 0.6 or more with ozone in a gas. Provided is a cleaning agent for removing contaminants.

According to the present invention, secondly, the distribution coefficient of the ozone in the gas on the surface of the object to which the contaminant adheres is 0.6.
An object of the present invention is to provide a method for removing contaminants adhering to a surface, which comprises contacting a treatment liquid in which ozone is dissolved in an organic solvent as described above to remove contaminants adhering to the surface of the object.

[0013]

Further, according to the present invention, as a preferred embodiment of the above method, a liquid film of the processing liquid is formed on the surface of the object to which the contaminant adheres, and the liquid film is continuously or intermittently formed. A method for removing contaminants adhering to a surface, characterized in that the surface of the object to be treated is brought into contact with the ozone-containing treatment liquid by supplying a new treatment liquid and moving the liquid film.

This is because certain organic solvents, such as acetic acid, dissolve ozone about ten times more than water, as discussed below, and even in liquid films, the ozone therein is not sufficient to act on surface-attached contaminants. It depends on the quantity. If the ozone concentration in the atmosphere in contact with the liquid film is higher than the equilibrium concentration with ozone in the liquid, ozone is easily diffused into the liquid film and the ozone concentration of the liquid rises to near saturation in a short time.

Accordingly, the present invention provides, as another preferred embodiment of the above method, a method of forming a liquid film of the organic solvent on a surface of a processing object to which a contaminant adheres in an atmosphere containing ozone, and continuously or intermittently. Providing a method for removing contaminants adhering to a surface, characterized by contacting the surface of an object to be treated with an ozone-containing treatment liquid by supplying a new solvent to the liquid film and moving the liquid of the film. Is what you do.

According to the present invention, in removing the above-mentioned contaminants adhering to the surface, the ozone-containing organic solvent liquid after the removal treatment is returned and combined with the organic solvent for dissolving ozone, and supplied as a treatment liquid for removing the object to be treated. It is an object of the present invention to provide a processing method and apparatus for circulating and using an organic solvent liquid. Non-polar organic solvents such as acetic acid are less likely to be decomposed by ozone. For example, acetic acid is one of the most stable substances to ozone in a common organic solvent, and has high solubility in ozone. This dissolved ozone has a strong reactivity with organic substances having an unsaturated bond, and has not only a decomposing effect, but also a carboxylic acid or carbon dioxide gas which is finally stable to ozone if sufficient reaction time is obtained. Decomposes into water. That is, in this circulation process, purification necessary for the removal treatment is performed, and the life of the removal treatment liquid can be extended. The most economical treatment of the present invention, which is extremely economical, is provided.

The supply of the organic solvent liquid may be carried out by spraying the liquid. In this case, the movement of the liquid on the membrane may be caused to flow down or by centrifugal force. Further, this liquid supply may be performed by liquefying the vapor generated from the heated liquid on the surface of the object to be cooled, and in this case, the adhered contaminants are removed by the vapor cleaning mechanism by the flow of the condensate. Will be removed. The present invention also provides an apparatus for removing adhering contaminants on the surface of the object to be processed, in which the liquid film on the surface of the object to be processed is moved in the chamber into which the ozone gas is introduced by supplying the organic solvent liquid.

In the present invention, when the contaminants adhering to the surface of the object to be treated are removed by the organic solvent, the organic solvent molecules are slightly adsorbed on the surface of the object to be treated. However, the amount of adsorption is as low as (10 ¹³ -10 ¹⁴ ) atoms / cm ^{2 in} carbon concentration. This is because even if the organic solvent contained in the contacted liquid is an organic substance, the molecule contains few carbon atoms and has an extremely high concentration of coexisting ozone. This is a feature of the present invention. In addition, the adhesion of the organic substance thus adsorbed to the object to be treated is weak, and the carbon concentration can be easily further reduced to a low order of 10 ¹² atoms / cm ² by the oxidizing treatment. The oxidizing treatment includes, for example, oxidizing washing such as alkali / hydrogen peroxide washing, or oxidizing treatment with ozone under irradiation of ultraviolet rays of 184.9 nm and 253.7 nm. Further, when the surface of the object to be processed is made of a silicon oxide film, the adsorbed molecules can be removed to a carbon concentration level close to this by slightly peeling off the surface layer with dilute hydrofluoric acid.

The organic solvent used in the present invention, which has a partition coefficient with ozone in the gas of 0.6 or more, is generally a non-polar organic solvent. The partition coefficient (D) is the partition coefficient of ozone between the organic solvent in the liquid phase in the standard state and the inert gas in the gas phase in contact with the organic solvent. That is, D = saturated ozone concentration in organic solvent (mg / L) / equilibrium ozone concentration in gas (mg / L). The partition coefficient of the organic solvent used in the present invention is preferably 1.0 or more, more preferably 1.5 or more, and further preferably 2.0 or more. If the organic solvent has a distribution coefficient with ozone in the gas of 0.6 or more,
Although it can be used in the present invention without particular limitation,
A preferable organic solvent from the viewpoint of effects on hygiene and the like is represented by the formula:
A fatty acid represented by C _n H _{2n + 1} (COOH) [n = 1, 2, or 3] and dichloromethane, and particularly preferably the fatty acid. The fatty acids include acetic, propionic and butyric acids. These organic solvents can be used alone or in combination of two or more.

In the present invention, the ozone concentration in the treatment liquid is preferably at least 100 ppm, more preferably at least 20 ppm. If the ozone concentration is less than 100 ppm, a sufficient pollutant removing action may not be obtained. Fatty acids having a purity of 99.7% as described above have substantially D = 1.
Since it is 9, an ozone solution having a concentration about 10 times higher than that of pure water can be obtained. Therefore, it shows much stronger pollutant removal capacity than ozone water. The removal treatment may be immersion in this ozone solution, but it is preferable to use an organic solvent having a very small surface tension of 30 dyn / cm or less for treatment with the liquid film. The liquid easily spreads in the form of a film on the entire surface of the object. Here, when the liquid moves, the surface contaminants acted on by the liquid also move at the same time, and efficient removal progresses. Also, the fine particles caught by the attached organic matter are easily removed because the organic matter dissolves in the liquid having a small surface tension and the liquid moves.

Among these carboxylic acids, acetic acid with n = 1 is preferred, because it is cost-effective, a commercially available product of high purity is easily obtained, and there is almost no problem in terms of toxicity. Melting point 16
Although it is difficult to handle at ℃, there is no problem at normal clean room temperature, and there is also an advantage in recovery as described later. Since propionic acid with n = 2 has a melting point of −20 ° C., the action of the acid is weakened and the ozone can be made high-concentration and low-temperature treatment can be performed on the object to be susceptible to acid. n =
Butyric acid No. 3 has a flash point of 72 ° C. and is about 20 ° C. higher than acetic acid or propionic acid. When it is desired to promote the reaction by heating, a treatment at about 70 ° C. is possible without danger.

Acetic acid, which contains a little water, dissolves the inorganic salt more easily and has a lower coagulation temperature and is easier to use. 97% purity
But D = 1.7, 95% D = 1.5, 90% D =
When D = 1.1 at 1.3 and 85%, a sufficiently high concentration ozone liquid can be obtained. Therefore, by adding water containing 5% by volume or less of inorganic acid, especially hydrofluoric acid, to acetic acid, metal contaminants can be removed well at the same time. Since such a high D value can be obtained, when ozone gas obtained by a high-purity ozone gas generator is bubbled from a large number of micropores to acetic acid having a purity of 85% or more, even if the ozone concentration is about 100 mg / L, the ozone concentration can be easily obtained. Is 100 ppm or more, which can be provided to the present invention. When an ozone gas having an ozone concentration of 200 mg / L is used, the ozone concentration of the liquid becomes 200 ppm or more in several minutes. When a glass filter is used as a divergent device for bubbling ozone gas, it can reach a concentration close to saturation in about 5 minutes, and the ozone concentration can be enhanced to nearly 400 ppm.

When an ozone gas having an ozone concentration of 300 mg / L is used, the ozone concentration of the liquid increases proportionally according to Henry's law, and the water content in the acetic acid is increased to 30% in consideration of the safety of the processing apparatus. Even so, the ozone concentration in the liquid becomes 200 ppm or more, and the effect of the removal treatment of the present invention can be sufficiently obtained. The blue-violet color of the liquid having such an ozone concentration becomes extremely sharp. Since the color density has a positive correlation with the ozone concentration, the ozone concentration of the liquid can be controlled to a predetermined value by simple colorimetry.

When it is not desired to use an acid or a water-soluble solvent which may cause rusting after the treatment, dichloromethane is preferred as the organic solvent. When D = 2.0, ozone is hardly decomposed and toxicity is relatively low. Further, dichloromethane is suitable for carrying out the present invention by a steam cleaning mechanism, and when carried out with a mixed solution with acetic acid, the effect of removing contaminants is further enhanced.

When a carboxylic acid is used in the present invention, a substrate for electronics industry is most suitable as the object to be treated. Adhered contaminants generated by adsorption from an environmental atmosphere or contact with an organic material can be easily removed. In particular, the positive type novolak resin-based resist on the silicon oxide film can be removed at a peeling rate of 1 μm / min to 6 μm / min, which is almost two orders of magnitude higher than the conventional one. In the case of dichloromethane, the object to be processed is preferably a metal processed product or a glass processed product, and a clean surface having a superior water droplet contact angle evaluation can be obtained as compared with the case of using alone for removing oily dirt and pitch / wax.
The shape of the object to be processed is preferably a plate shape, but may be any shape as long as the movement of the liquid film is not largely uneven.

In order to carry out the present invention, it is necessary to perform treatment in an airtight chamber or a fume hood so that harmful ozone gas does not pollute the ambient air. Since the treatment is performed at room temperature, the evaporation of the organic solvent is relatively small. The exhaust pipe from the hermetic chamber is connected to an ozone decomposer utilizing ultraviolet irradiation of a wavelength of 253.7 nm or alkali solution treatment. If a cooling mechanism is provided in the exhaust system, the organic solvent can be liquefied and recovered. When acetic acid is used, it easily freezes, so that a high recovery rate can be obtained. Therefore, the present invention can be implemented with almost no pollution of the environment.

When the wafer is put in a carrier and immersed in ozone-containing acetic acid for the resist removal treatment according to the present invention, the resist is peeled off at a high speed, so that the influence of the carrier as in the case of immersion in ozone water is small, and the periphery is even. The resist can be stripped. However, in the case of the immersion treatment, the treatment liquid is used repeatedly. Therefore, if the treated wafer is immediately put into a pure water rinsing bath, a dissolved substance precipitates on the wafer surface and conversely causes contamination. Therefore, a rinse tank for acetic acid is required, and the amount of the chemical solution in the apparatus becomes too large.

In the treatment with the liquid film of the present invention, even if the amount of the liquid is small, the ozone concentration is high, so that the reaction to the contaminants is fast, and the liquid moves and the dissolved contaminants are separated from the object with time. Therefore, the removal ability is higher than the immersion method. The movement of the liquid in the form of a film utilizes the spreading from the center due to the falling or centrifugal force. The moving speed of the liquid is sufficient if the supply amount is about 1 to 3 mL per minute for a 6-inch wafer. The apparatus can be configured in the same manner as a usual spray cleaning apparatus, single wafer spin cleaning apparatus, or steam cleaning apparatus. In order to quickly increase the ozone concentration in the liquid film processing which is a feature of the present invention, and to maintain the concentration, an inlet and an outlet for ozone gas are provided in chambers of these apparatuses,
It is effective to fill the chamber with ozone gas, which is a feature of the present invention. However, when using a high concentration ozone gas having an ozone concentration exceeding 200 mg / L, it is not necessary to introduce the ozone gas into the chamber.

[0029]

EXAMPLES The ozone gas used in the following examples is a small discharge type ozone generator containing oxygen containing 1% of nitrogen at 0.1%.
The ozone concentration obtained by flowing 5 to 2 L / min is about 200 mg / L. Acetic acid that absorbs ozone gas is 99% pure
(Remaining water) was used. The photoresist film subjected to the removal treatment in each embodiment is 800 nm and 1.5 μm thick on a p-type silicon wafer provided with a 100 nm oxide film. The processing for forming the resist film was performed by a standard procedure using a coating apparatus that is used in a normal LSI process. First apply HMDS, 100 ℃ including evacuation
After cooling to room temperature, a novolak resin-based resist was applied in the above thickness. Baking is performed at 140 ° C for 1 minute for thin resist films and at 90 ° C for 2 minutes for thick resist films.
For the latter, a sample in which a high dose of ion implantation was performed was also prepared.

In an advanced VLSI, the amount of organic matter remaining after the resist is stripped is extremely small (2 × by organic carbon concentration).
(10 ¹³ atoms / cm ² or less), the amount of organic matter remaining on the silicon oxide film after the resist is stripped in the present embodiment is determined by the high-sensitivity charging described in Japanese Patent Application No. 10-253346. The absolute amount of surface organic carbon was determined by particle activation analysis.

The cleaning effect on organic contamination on the silicon wafer in the present invention was confirmed by the same charged particle activation analysis that the residual organic carbon concentration after cleaning was sufficiently reduced by using a sample which was intentionally strongly contaminated with organic. . Also, since it is known that most of the contaminants that contaminate silicon wafers in a clean room of a semiconductor factory are DOP, a ¹⁴ C-labeled DOP was synthesized, and the intentionally contaminated silicon wafer was used. The remaining amount after washing was determined by measuring radioactivity by radioluminography using an imaging plate.

When the contaminants adhering to the flat surface are oils and fats or HMDS, the contact angle of the water droplet is increased. Therefore, the effect of removing such contaminants is determined by whether the contact angle of the water droplet is reduced to about several degrees. did.

Embodiment 1 FIG. 1 is a conceptual diagram of an apparatus for removing a plurality of wafers with a photoresist film placed in a carrier by immersing the wafers in an ozone acetic acid solution. The draft made for the experiment is divided into a front room 1, a processing room 2, and a rear room 3, and there is a glass door on the whole surface. However, the inside of the draft is isolated from the outside during operation, and all operations are performed outside. You. An atmosphere containing ozone and acetic acid in the processing chamber is provided in the front and rear chambers so that the quartz glass carrier 5 containing seven wafers 4 can be put into the processing chamber from the front chamber and taken out through the rear chamber after processing. And a door opening 6 that can be opened and closed with an air displacement mechanism (not shown) to prevent the air from leaking out of the draft.

The quartz glass tank 7 is a tank for performing ozone treatment in acetic acid, and the quartz glass tank 8 is an acetic acid rinse tank. The quartz glass tank 9 is an overflow rinsing tank in which ultrapure water is supplied and drained through an inlet pipe 11 having a valve 10 and a drain pipe 12.

Acetic acid is supplied to a rinsing tank from an introduction pipe 14 having a valve 13, and acetic acid filled in the rinsing tank is supplied to a conducting pipe 15.
To enter the ozone treatment tank 7. Acetic acid that has undergone wafer processing is gradually discharged to a drain tank through a drain pipe 17 having a valve 16. The amount of the processing solution in each tank is about 5 L.

Ozone gas is introduced into the ozone treatment tank through a quartz glass tube 18, and the tip 19 of the tube is disposed at the bottom of the tank, and is provided with a large number of fine holes for gas diffusion. When ozone gas was supplied at a rate of 2 L / min, the ozone concentration in the acetic acid reached 200 ppm or more in 5 minutes.

A carrier on which a wafer having a resist film of 800 nm is set is mounted on the robot arm 20 in the front chamber, immersed in an ozone acetic acid tank having an ozone concentration of 200 ppm or more for 1 minute, and then rinsed in an acetic acid rinsing tank for 1 minute. Acetic acid drops were dropped for 30 seconds, and when the wafer surface reached a state where the wafer surface was covered with a thin acetic acid film, it was transferred to an ultrapure water tank and overflow rinsed for 3 minutes, and the carrier was taken out in the rear chamber. When the wafer was spin-dried and inspected with the naked eye, no resist remained on the entire surface.

The wafer is cut into 2 cm × 2 cm chips,
When the charged particle activation analysis was performed, the surface organic carbon concentration was 4 × 10 ¹⁴ atoms / cm ² . Although the resist has been removed, there is a possibility that a part of the methyl silicon layer may remain in addition to the adsorption of acetic acid molecules. However, this ozone acetic acid treatment has a stripping ability of 800 nm / min or more, that is, a strong stripping ability of one digit or more by the ozone water treatment, to the novolak resin-based resist.

Acetic acid vapor and ozone gas generated in the draft are exhausted from an exhaust port 21 by a fan and exhausted as shown in the conceptual diagram of FIG. When the ozone concentration in the acetic acid in the tank 7 exceeds 100 ppm, the blue-violet color due to ozone becomes vivid. Since the color density has a positive correlation with the ozone concentration, the light source 22 and the light receiving unit 23 measure the absorbance at a wavelength of 595 nm, and when the ozone concentration reaches a predetermined value, the supply of ozone gas is stopped. Ozone emissions can be controlled to a minimum.

The exhaust pipe 24 following the exhaust port terminates in a freezing chamber 26 with an outlet pipe 25. The freezing chamber is housed in a heat exchanger 27 capable of not only cooling but also heating. The effluent pipe is detachable from the acetic acid recovery tank 28 and the ozone exhaust pipe 29
Protrudes into the attached sealed tube 30. A blower 31 was connected to the ozone exhaust pipe, and the atmosphere in the sealed draft was exhausted by the blower during the operation of this embodiment. At this time, the inside of the freezing room is lowered to 10 ° C. or less by operating the heat exchanger, and the acetic acid in the exhaust is frozen inside the room. After a series of operations, the frozen acetic acid is heated and melted and collected in a tank.

The exhaust gas passed through the blower was discharged from a low-pressure mercury lamp.
It is introduced into a 7 nm UV irradiator to decompose ozone and acetic acid that is slightly remaining. In this example, no ozone odor or acetic acid odor was felt in the atmosphere outside the draft.

Example 2 Ozone acetic acid immersion 1 of Example 1
The remaining amount of organic carbon was slightly higher in
Similarly, the treatment was performed at an ozone concentration of 200 ppm or more. Wafers in which a high dose ion implantation was performed on a 1.5 μm resist film were also used, and wafers without resist coating were added as controls to the following six types of samples and set on a carrier. The pure water rinse was treated for 10 minutes by exchanging a 1 MHz ultrasonic vibrator with an overflow rinse tank attached to the lower part in order to remove acetic acid molecules adsorbed on the surface. (1) 800 nm resist film wafer (2) 1.5 μm resist film wafer (3) B ⁺ ion implanted wafer at 30 KeV and dose of 1 × 10 ¹⁴ / cm ² (4) Ashing 1 μm to (3) (5) Wafer that has been implanted with B ⁺ ions at 30 KeV and at a dose of 1 × 10 ¹⁵ / cm ² (6) Wafer that has undergone 1 μm ashing on (5) No resist remained with the naked eye, except that only × 10 ¹⁵ / cm ² clearly left the resist. However, when the surface dust count was performed, contamination by the desorption resist from the 1 × 10 ¹⁵ / cm ² ion-implanted resist film was remarkable. .
The number of fine particles of 2 μm or more was 15 or less. As a result of the charged particle activation analysis, the amount of organic carbon was all (7 to 10) ×
At 10 ¹³ atoms / cm ² , it is estimated that the resist including those implanted at 1 × 10 ¹⁴ / cm ² was completely removed, and most of the methyl silicon layer was also removed. For these wafers, NH ₄ OH: H ₂ O ₂ : H ₂ O = 1 volume: 1
Volume: After a 12-volume SC-1 wash, the residual organic carbon content is (4-7) × 10 ¹² atoms / cm ^{2 for} all samples.
The methyl silicon layer and the adsorbed acetic acid were completely removed.

Example 3 Since ozone acetic acid has a high resist dissolving ability, ozone acetic acid was supplied to a wafer by a spray nozzle 32 as shown in FIG. 3, and an attempt was made to remove the resist by flowing down a liquid film. In a chamber 34 covered with a lid 33 that can be moved up and down, there are an inlet pipe 36 and an ozone gas outlet pipe 37 through which ozone gas can be supplied by a valve 35, and a table 39 on which the carrier 5 on which the wafer 4 is set is slightly rocked by a shaft 38. It has been incorporated. The valve 40 is located at the discharge pipe 41 of the processed acetic acid, is closed during the processing, and discharges after the processing. Ozone gas is introduced into the chamber at a rate of 2 L / min, the carrier is rocked, and ozone acetic acid is dropped onto the wafer from the spray nozzle located on the wafer. Spraying is first performed until the entire surface of the wafer is wet, and thereafter, intermittently performed so that ozone acetic acid drops from the lower end of each wafer.

The spraying of ozone acetic acid is carried out by sending ozone acetic acid in an absorption vessel 42 having an impinger structure into a spray pipe 45 at a nitrogen pressure through an electromagnetic valve 44 by a three-way cock 43. Ozone acetic acid was prepared by previously sending ozone gas at a rate of 1 L / min into acetic acid in a 500 mL container through a valve 46 and an inlet pipe 47 and a perforated nozzle 48 via a valve 46 to absorb ozone. The acetic acid was introduced through the introduction pipe 49 and the valve 50.

The resist was stripped except for the sample (5) shown in Example 2. The spraying process was performed for 10 minutes including the intermittent stop time, with a spray liquid amount of 20 cc per sheet.
Thereafter, only nitrogen-containing oxygen was flowed from the inlet tube 36 to dry the acetic acid on the wafer. In contrast, Example 2
After the SC-1 washing was performed in the same manner as in Example 1, the amount of residual organic carbon was (3 to 7) × 10 ¹² atoms / cm ² , and 0.1%.
The number of particles having a size of 6 μm or more was 10 or less for each wafer. When the same treatment was performed with propionic acid instead of acetic acid, the residual carbon amount was not significantly different from that of acetic acid.

Example 4 Sample (5) of Example 2 (1)
The ozone acetic acid spraying treatment was performed on the × 10 ¹⁵ ion-implanted resist in the same manner as in Example 3. However, 1 /
200 volumes of hydrofluoric acid (49% by weight) were added. 10 minutes, 1
With intermittent spraying of 20 cc per sheet, the resist could hardly be removed, but it was clearly embrittled. When the wafer was subjected to high-pressure jet spray of ultrapure water and spin-dried, the contact angle of water droplets on the oxide film surface was 5 ° or less. On the other hand, when the SC-1 cleaning was performed, the residual organic carbon amount was 6 × 10 ¹² atoms / cm ² , and the high-dose ion-implanted resist could be removed.

Example 5 For four oxidized wafers having the same specifications as those used in each of the above examples, Na labeled with ²² Na was labeled with 7 × 10 ¹¹ atoms / cm ² and ⁵⁷ Ni, respectively. Cu labeled with Fe labeled with the Ni in 2 × 10 ¹¹ atoms / cm ^{2, 59} Fe in 5 × 10 ¹¹ atoms / cm ^{2, 64} Cu
Was intentionally contaminated at 5 × 10 ¹¹ atoms / cm ² . This contamination causes the chlorides of the respective elements to adhere to the wafer surface so as to be substantially uniform by an evaporation method devised with an aqueous solution.
It was dehydrated at ℃. Thereafter, HMDS coating treatment was performed, and the ability to remove metal contamination by hydrofluoric acid-containing ozone acetic acid treatment when there was strong organic contamination was examined.

Spraying was performed with hydrofluoric acid-containing ozone acetic acid in the same manner as in Example 4 and stopped in 3 minutes as in Example 3, and the carrier was rinsed with ultrapure water for 1 minute using a spin dryer with pure water rinse. . For all wafers, the water droplet contact angle is less than 4 °,
It was found that the methyl silicon layer by HMDS was substantially removed. Further, the measurement of the radioactivity of each wafer showed that all the elements became 3 × 10 ⁹ atoms / cm ² or less, and it was found that this treatment was also effective for removing metal contamination.

[Embodiment 6] A wafer having the same specification as that used in each of the above embodiments was immersed in hydrofluoric acid to remove an oxide film. Cu labeled with ⁶⁴ Cu that emits gamma rays in time
Is adsorbed at 1 × 10 ¹¹ atoms / cm ^2, and 1 × 10 ¹⁴ molecules (2.4 × 10 ¹⁵ carbon atoms) of ¹⁴ C-labeled DOP, which has a very long half-life and emits only β rays, are adsorbed on its back surface. / Cm ² . The sample was subjected to hydrofluoric acid-containing ozone acetic acid treatment and pure water rinsing / drying in the same manner as in Example 5 to measure gamma rays. As a result, the residual amount of Cu was 2 × 1
It was ⁹ atoms / cm ² . The ^{6 4} beta rays from Cu disappeared after 1 week performed beta ray measurement was determined the residual amount of DOP, was 7 × 10 ¹² atoms / cm ² at a carbon concentration. Therefore, this ozone acetic acid treatment is sufficiently effective in removing contaminants such as organic substances and metals attached to the back surface.

Embodiment 7 A single-wafer spin ozone acetic acid treatment apparatus as shown in FIG. 4 was prepared by modifying a single-wafer washing machine capable of spin cleaning, spin rinsing and spin drying of diluted hydrofluoric acid.
A low-pressure mercury lamp 54 was incorporated in a lid 53 of a chamber 52 having a spin axis 51. Three C-200UZs were used in parallel. 184.9nm UV light from mercury lamp without loss
A part of the lid was formed as a synthetic quartz glass plate 57 so as to reach the surface of the wafer to be processed 56 held in the substrate. An ozone gas introduction pipe 59 supplied by a valve 58 is provided in the chamber 52.
And an exhaust pipe 60, and an acetic acid introduction pipe 61 that rotates only during ozone acetic acid treatment and drops acetic acid or ozone acetic acid at the center of the wafer, and an ultrapure water introduction pipe 62 for rinsing ultrapure water after treatment are attached. are doing. Inflow is made by valves 63 and 64, respectively.

With respect to the sample (1) of the 800 nm resist film shown in Example 2 and the sample (4) ashed after ion implantation, the resist was stripped by this apparatus. In each case, the rotational speed of the wafer was 100 rpm, and ozone gas having an ozone concentration of 200 mg / L was supplied at 2 L / min. From 61, 200 ppm or more ozone acetic acid prepared in an ozone absorbing container similar to that shown in Example 3 was introduced into the center, and about 80 drops were dropped in one minute when the entire surface of the wafer was wet. Thereafter, ultrapure water is allowed to flow in for 20 seconds for spin rinsing, introduction of ozone is stopped, and the wafer is spin-dried at 4000 rpm.
UV light was applied for a minute. As a result of charged particle activation analysis of the wafer, residual organic carbon was 3 and 5 × 10 ¹² atoms / cm.
^{In 2} , both the resist and the methyl silicon layer were sufficiently removed.

[Embodiment 8] In the apparatus of FIG. 4 used in the previous embodiment, the chamber lid 53 is simply provided with the function of a lid without providing a low-pressure mercury lamp. An acid inlet tube was added. 800n shown in Example 2
After the ozone acetic acid treatment and the pure rinsing were performed on the (1) sample of the m resist film in the same manner as in the previous example, the diluted hydrofluoric acid (hydrofluoric acid: water-1 volume: 50 volume) was rinsed for 15 seconds, and the pure water rinse was performed. After 15 seconds, spin drying was performed in the same manner as in the previous example. The residual carbon content is 1 × 10 ¹³ atoms / cm ^2, which is slightly higher than that of the previous embodiment, but the adsorbed molecules which can be sufficiently used in device manufacture are removed.

[Embodiment 9] An oxide film is removed as in Embodiment 6.
SC-1 process on the wafer¹⁴C-labeled DO
Dissolve P in hexane and apply over the entire surface
To a DOP concentration of 1 × 10¹⁴Molecule / cm^TwoIntentional
A contaminated sample was made. Introducing pipe 6 using the apparatus of Example 7
1 to 99% pure propionic acid was introduced, and
Perform the treatment for 1 minute and rinse with pure water and UV irradiation
Was. However, the rotation speed of the wafer is 50 rpm, the wafer
The amount of dripping after wet was 50 drops. Radioactivity after treatment
As a result of measurement, the residual DOP was 2 × 10¹¹Molecule (5
× 10 ¹²Carbon atom / cm^Two), DOP is sufficiently removed
Came.

[Embodiment 10] An embodiment in which the liquid film processing according to the present invention is performed by a steam cleaning mechanism will be described with reference to FIG. A lid 65 that can be moved up and down,
And a cooling pipe 70 for cooling a plate-like glass workpiece 69 containing a carrier 68 set above the liquid.
1 constitutes this device. The feature of this device is that an ozone gas introduction pipe 73 having a valve 72 and an ozone gas exhaust pipe 74 are provided. The leading end of the introduction tube is connected to a perforated tube 75 for generating a fine gas of ozone and dichloromethane by generating fine bubbles of ozone gas in the liquid. The device was made of stainless steel plates and tubes.

A glass plate coated with a pitch for lens polishing is set on a carrier as a deliberately contaminated sample, and about 200 mg / L
Steam cleaning was performed while flowing ozone gas having a concentration of 2 L / min. Each was dried in 10 minutes and the contact angle of water droplet was measured.
The angle is reduced from 0 to 35 ° to about 10 ° or less. After this, C-20
When UV irradiation with 0 UZ was performed for 2 minutes, the water droplet contact angle was 3 °. In the case of a cleaning product using only dichloromethane, ultraviolet irradiation required 20 minutes or more to obtain this angle.

[Embodiment 11] An iron plate from which oily dirt was required to be removed as a pre-plating treatment was set on the carrier of Embodiment 9 and subjected to steam cleaning treatment and ultraviolet treatment for 2 minutes in the same manner as in this embodiment. The contact angle changed from 55 ° before washing to 4 °.

Example 12 200 mg / L to 300 m
An ozone generator capable of obtaining g / L high-concentration ozone at a flow rate of 0.5 to 1 L / min was prepared. A quartz glass impinger (volume 1) with a quartz glass filter at the nozzle end
00 mL) with acetic acid added with water in different proportions,
1% containing 220mg / L of ozone created by the generator
Nitrogen-containing oxygen gas was bubbled, and after 5 minutes, the concentration of ozone dissolved in the liquid was measured assuming that ozone was saturated.
The quantitative method is a volumetric analysis method using a reaction in which potassium iodide is converted to iodine with ozone. The dotted line in FIG. 6 shows the relationship between the acetic acid concentration of the aqueous acetic acid and the obtained saturated ozone concentration (liquid temperature is 20 ° C.).

The acetic acid concentration of ozone-saturated aqueous acetic acid and the novolak resin-based resist IX555 of ozone-saturated acetic acid
FIG. 6 shows the relationship between the peeling speed and the peeling speed (manufactured by JSR Corporation). An experiment to determine this relationship was performed as follows. The above IX5 is applied to the 100 nm oxide film wafer on which the HMDS coating treatment has been performed as described above.
55 was applied to a thickness of 1.5 μm, baked at 140 ° C. for 60 seconds, cut into squares of 2 cm × 2 cm, and 10 mL of the above ozone-saturated acetic acid was added to the bottom of a small quartz beaker and rocked. Then, the time required for the resist to be completely peeled off is determined with the naked eye, and the peeling speed is calculated from the value. From this figure, it can be seen that when 220 mg / L ozone gas is used, the ozone saturation amount is 380 mg / L, and the peeling rate of acetic acid having a purity of 98% or more against the novolak resin resist IX555 reaches 6 μm / min or more. In the present invention, when the ozone concentration in acetic acid approaches 400 mg / L, a resist film having a thickness of 1.5 μm can be removed in a very short time of about 15 seconds.

Embodiment 13 As in the previous example, when the concentration of ozone gas is increased and a glass filter is used to emit ozone, acetic acid having a high concentration of about 400 ppm of ozone can be easily obtained, and novolak can be obtained by contact for 30 seconds or less. Since the resin-based resist can be removed, it can be said that such a treatment with acetic acid having a high ozone concentration preferably uses a single-wafer spin cleaning mechanism.
Therefore, a resist removing apparatus having a cross-sectional view shown in FIG. 7 was prepared using the single wafer spin cleaning mechanism of the seventh embodiment.

The wafer 55 to be processed in the single-wafer spin processing is configured such that the support member 55 is driven by a rotation mechanism 76 by a spin rotation shaft 51 and spins.
Chamber 5 for collecting the processing liquid scattered during spin processing
It is surrounded by two. This single-wafer processing mechanism and a support table 7 for a wafer cassette 77 for accommodating all of the wafers to be processed.
8 and a transfer robot 79 for automatically loading and unloading wafers between the cassette and the supporting member 55.
0 is provided. It should be noted that a mechanism for automatically opening a part 80 of the wall surface of the chamber when the wafer enters and exits is provided. A processing liquid supply pipe 83 having a nozzle 82 for discharging ozone acetic acid on the surface of the wafer at a terminal thereof,
An acetic acid supply pipe 85 having a nozzle 84 for discharging acetic acid for rinsing at the end thereof penetrates. Incidentally, these two supply pipes can be integrated into one by a valve operation.

A liquid discharge pipe 86 for discharging acetic acid collected at the bottom of the chamber, a gas introduction pipe 87 for replacing the atmosphere in the housing, and an ozone decomposer (not shown) using a catalyst such as Mn. 2) penetrates the housing wall. The housing is provided with an openable / closable door 6 for taking a wafer cassette in and out, and opens and closes only when ozone and acetic acid are discharged from the atmosphere in the housing. The ozone acetic acid solution can be prepared by feeding ozone gas to the acetic acid 88 stored in the ozone absorbing container 42 to the ozone radiator 89 of the quartz glass filter through the pipe 59 through the valve 58. Normally, a saturated ozone concentration is almost reached by 5 minutes of ventilation. This liquid is supplied to the nozzle 82 by the supply pipe 83 for a predetermined time through a Teflon (registered trademark) liquid supply pump indicated by P and a precision filter for dust indicated by F. The supply of acetic acid to the ozone absorbing container and the discharge from the container are performed by a pipe 91 having a valve 90.
Do with. Acetic acid 92 for rinsing is placed in a separate container 93 with valve 9
4 is supplied through a pipe 95. The rinsing liquid is sent to the rinsing nozzle 84 for a predetermined time by a pipe 85 passing through a liquid sending pump and a dust precision filter.

As described above, HMDS was applied to a 6 ″ wafer having a 100 nm oxide film to form a 1.5 μm film of photoresist IX555, and 25 films baked at 140 ° C. for 60 seconds were prepared. About 300 mL of acetic acid was placed in an ozone absorbing container 87, and nitrogen-containing oxygen having an ozone concentration of 220 mg / L was bubbled from an ozone diffuser at a flow rate of 1 L / min. The maximum concentration reaches 380 mg / L per minute.The wafer 56 is rotated at 1000 rpm and the ozone acetic acid is discharged from the nozzle 82 at a speed of 1.5 mL / second. Further, the acetic acid in the acetic acid container 93, which has been continuously released for 20 seconds, is rinsed from the nozzle 84 at a speed of 1.5 mL / second for 10 seconds, and the rotation of the wafer is reduced by 40 minutes. The wafer was spin-dried for 30 seconds after increasing to 0 rpm, and processed continuously for 25 wafers after replacing the wafer in the cassette, but the time required for the visual stripping despite the fact that the resist decomposition residue in the ozone absorbing container should accumulate. About 15 seconds remained the same until the end.

The cassette from which all of the wafers have been peeled is taken out of the housing, and then subjected to spin-drying after 10 minutes of ultrapure water overflow rinsing with a normal cleaning device, and 2 cm × 2 cm square chips are cut out from these wafers. When the amount of residual organic carbon was examined by charged particle activation analysis (0.8
In to 2.6) × 10 ¹³ atoms / cm ^2, HMDS film not resist but also was found to have been almost removed.
The reason why the processing solution is not deteriorated is that when the waste ozone acetic acid solution after the single-wafer processing returns to the ozone-saturated container, high-concentration ozone is always present. It is considered that the purification proceeds to a purity level sufficient for reuse, while acetic acid hardly changes even at a high concentration of ozone. That is, in this treatment method, the treatment solution can be circulated and reused, and it can be said that only newly required acetic acid is used for rinsing. The rinsing liquid is gradually discharged by the valve 90 because the amount of liquid in the absorption container increases. However, since the acetic acid purity of the discharge is high, the acetic acid is recovered at an extremely high recovery rate by distillation and can be used for rinsing.

Embodiment 14 A technegas apparatus used for medical diagnosis of the respiratory system is an apparatus for creating an argon atmosphere in which ultrafine carbon dust of 0.1 μm or less is dispersed.
The microparticles are labeled with ^99m Tc with a half-life of 6 hours. The wafer with the resist film used in the previous embodiment with this apparatus
The film surface of C was contaminated, and the radiation dose due to the attached carbon particles on the entire surface was determined by radioluminography using an imaging plate, and found to have a radioactivity of 2600 PSL / cm ² . A single-wafer experimental device was prepared exclusively for the radiation experiment. The resist was removed under the same stripping conditions using an acetic acid solution having the same ozone concentration as in the previous experiment, rinsed with acetate, dried, and then subjected to the same radioluminography measurement. The radiation dose based on the residual carbon particles was 20 PSL / cm ² or less of the background. This ozone acetic acid treatment was found to be effective for removing fine particles.

[Embodiment 15] According to Henry's law, the ozone concentration of the ozone acetic acid solution also increases in proportion to the ozone concentration in the gas emitted in acetic acid. The relationship between the acetic acid concentration in the aqueous acetic acid and the saturated ozone concentration when the ozone concentration in oxygen was increased to 280 mg / L is shown by the broken line in FIG. When the acetic acid concentration is reduced to 80% by volume, explosion-proofing of the device is not required, and there are many structural advantages. If the ozone concentration in the gas to be radiated is 280 mg / L even if there is moisture, the ozone concentration in acetic acid will be 250 ppm, the stripping speed of the novolak resin resist will be about 1 μm / min, and single wafer spin processing will be possible. . Novolak resin resist IQ2002 (Tokyo Ohka Kogyo Co., Ltd.)
The experiment was performed in exactly the same manner as in Example 12 except that the ozone concentration in oxygen was 280 mg / L, acetic acid was 80% by volume (remaining water) in both containers, and the ozone acetic acid release time was 1 minute. The macroscopic resist stripping time was 45 seconds on average. When the residual organic carbon concentration was measured in the same manner as in Example 12, the concentration was 3 × 10 ¹³ atoms / cm ² or less, and most of the HMDS layer could be removed. Furthermore, when the SC-1 treatment was performed thereafter, the residual organic carbon concentration was 5%.
At less than × 10 ¹² atoms / cm ² , a degree of cleanliness that could be said to be too sufficient was obtained.

[0066]

In the semiconductor lithography process, the positive resist on the oxide film, including the methylsilicon layer at the interface derived from the adhesive HMDS, is to be removed until the residual organic carbon content is 10 ¹³ atoms / cm ² or less. Then, in the conventional method, piranha treatment whose composition is sufficiently controlled is performed, and SC-
One process must follow. Piranha treatment is 130
High temperature treatment of about ℃ is required, and the component H ₂ O ₂ is decomposed to H ₂ O to dilute the solution, reducing the effect. At that time, sulfuric acid becomes a mist and scatters, thus causing environmental pollution. Countermeasures have become an important issue. The present invention is for ozone treatment,
Although a closed system is required, the exhausted ozone gas can be easily decomposed, and the amount of the organic solvent such as acetic acid scattered is small because the treatment is performed at room temperature, and when acetic acid is used, it can be recovered by cooling before the decomposition treatment. In the present invention, if the ozone acetic acid solution after the removal treatment is restored to an ozone dissolving (absorbing) solution for bubbling ozone, the ability to decompose ozone-treated contaminants, such as a novolak resin-based resist, is strong. In the case of the resin, naphthoquinone azide of the photosensitizer through phthalic acid etc.
Decomposes into glyoxal and glyoxylic acid, and finally from formic acid into water and carbon dioxide. That is, purification is performed in the process of ozone bubbling, and acetic acid is used for a long life.
In short, the organic solvent is purified by ozone, and the amount of use is extremely small compared with the case where the other resist remover that merely dissolves accumulates and degrades the dissolved substance, and has an effect of being excellent in economical efficiency. Therefore, in the present invention, both ozone and such an organic solvent can easily take measures against environmental pollution. In particular, acetic acid is very safe because of its very low toxicity.

Further, compared with the piranha treatment and the conventional ozone treatment, the treatment method of the present invention has a stripping speed for such a resist that is one to two orders of magnitude higher. This is because the organic solvents used in the present invention have an ozone solubility of about 10 times that of water, and these organic solvents are not easily decomposed by ozone. In addition, since these organic solvents have a low surface tension and easily spread on the surface of the object, the surface of the object can be efficiently treated with the organic solvent liquid film having a high ozone concentration. Therefore, it can be processed with a small amount of liquid,
Since the liquid film treatment is performed in an ozone atmosphere in order to keep the ozone concentration in the liquid film as high as possible, the amount of ozone gas used can be smaller than in the case of ozone water treatment.

Since the positive resist stripping ability of the present invention is extremely strong, the 1 × 10 ¹⁴ / cm ² B ⁺ ion-implanted resist easily dissolves, and even with the 1 × 10 ¹⁵ / cm ² implanted resist,
If high-pressure jet spray cleaning is performed later, a chemical action (brittleness) that can be sufficiently removed can be given. The resist in which the ion-implanted layer has been ashed can be removed by a one-minute sheet-wafer ozone acetic acid liquid film treatment. In addition, since the surface tension of the liquid is small, in the device manufacturing process having a fine pattern, the resist removing effect can be easily provided to every corner of the pattern, and fine particles can be removed well. In addition, since the acid treatment with strong oxidizing power using high-concentration ozone enables removal of various contaminants such as removal of metal contamination, it has an advantage as a cleaning agent.

The carboxylic acid molecules such as acetic acid adsorbed by the treatment of the present invention are ionized during the subsequent pure water rinse. These molecules ionized easily oxidized, for example, lost by decomposition in a very short time in the UV-ozone treatment, the other alkali - the same in the hydrogen peroxide treatment, the present invention is easily surface organic carbon concentration of 10 ¹² atoms / Cm ² .

The effect of the liquid film treatment of the ozone organic solvent in the ozone atmosphere according to the present invention can be easily applied to the vapor cleaning of dichloromethane having high ozone solubility, low surface tension and relatively low toxicity. This treatment, in combination with the short-time ultraviolet ozone treatment, has the effect of simplifying the advanced removal of contaminants such as organic substances when adhesion of water is not desirable.

[0071]

[Brief description of the drawings]

FIG. 1 is a conceptual diagram in a case where the present invention is performed by immersion of an object to be processed.

FIG. 2 is a conceptual diagram relating to the treatment of an ozone exhaust gas containing acetic acid.

FIG. 3 is a longitudinal sectional view of a liquid film falling-down processing apparatus using an ozone acetic acid liquid spray according to the present invention.

FIG. 4 is a longitudinal sectional view of a single-wafer liquid film transfer processing apparatus under ozone acetic acid droplets of the present invention.

FIG. 5 is a longitudinal sectional view of a dichloromethane vapor cleaning apparatus in an ozone atmosphere according to the present invention.

FIG. 6 shows the relationship between the acetic acid concentration of hydrous acetic acid and the saturated ozone concentration obtained in Example 12 (dotted line: ozone concentration: 220 ppm, dashed line: ozone concentration: 280 ppm), and the acetic acid concentration of ozone-saturated aqueous acetic acid and novolak resin. The relationship (solid line) with the stripping rate for the system resist is shown.

FIG. 7 is a conceptual diagram illustrating a resist removing apparatus according to the present invention.

[Explanation of symbols]

1. Pre-draft room 2. Draft processing room
3. Post-draft room 4. 4. Wafer to be processed Wafer carrier
6. 6. Door that can be opened and closed Ozone acetic acid treatment tank 8. Acetate rinse tank
9. Pure water rinse tank 10. Pure water valve 11. Inlet pipe for pure water 1
2. 12. Water distribution pipe for pure water Acetic acid valve 14. Acetic acid introduction tube 1
5. Acetic acid conduit 16. Drain valve 17. Drain pipe 1
8. Ozone gas introduction pipe 19. Ozone emission tube 20. 21. Robot arm for carrier movement Draft exhaust 22. Ozone colorimetric light source 2
3. Ozone colorimetric light receiving section 24. Exhaust pipe 25. Dissolved acetic acid outlet tube 2
6. Acetic acid freezing chamber 27. Heat exchanger for cold heat 28. Acetic acid recovery tank 2
9. Ozone exhaust pipe 30. Tank cap sealed tube 31. Blower 3
2. Ozone acetic acid spray nozzle 33. Chamber lid 34. Chamber 3
5. Ozone gas valve 36. Ozone gas inlet pipe 37. Ozone gas discharge pipe 3
8. Carrier swing axis 39. Carrier swing table 40. Acetic acid discharge valve 4
1. Acetic acid discharge pipe 42. Ozone absorption container 43.3 way cock 44.
Electromagnetic valve for nitrogen pressure feed 45. Ozone acetic acid spray tube 46. Ozone gas valve 4
7. Ozone gas inlet pipe 48. Ozone gas emission nozzle 49. Acetic acid introduction tube 5
0. Acetic acid valve 51. Spin washer spin axis 52. Chamber 5
3. Chamber lid 54. Low pressure mercury lamp 55. Wafer support 5
6. Target wafer 57. Synthetic quartz glass plate 58. Ozone gas valve 5
9. Ozone gas inlet pipe 60. Ozone gas discharge pipe 61. Acetic acid introduction tube 6
2. Pure water introduction pipe 63. Acetic acid valve 64. Pure water valve 6
5. Chamber lid 66. Dichloromethane reservoir 67. Heater 6
8. Object carrier 69. Plate-shaped object 70. Cooling pipe
71. Chamber 72. Ozone gas valve 73. Ozone gas introduction pipe 7
4. Ozone gas discharge pipe 75. Ozone gas emission tube 76. Rotating mechanism 7
7. Wafer cassette 78. Support base 79. Transfer robot 8
0. Housing 82. Nozzle 83. Treatment liquid supply pipe 8
4. Nozzle 85. Acetic acid supply pipe 86. Liquid discharge pipe 8
7. Gas inlet tube 88. Acetic acid Ozone diffuser 9
0. Valve 91. Piping 92. Acetic acid for rinsing

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] November 2, 2000 (200.11.
2)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction contents]

In the present invention, the ozone concentration in the treatment liquid is preferably at least 100 ppm, more preferably at least 200 ppm. If the ozone concentration is less than 100 ppm,
Sufficient pollutant removal action may not be obtained. Fatty acids having a purity of 99.7% as described above have substantially D =
Since it is 1.9, an ozone liquid having a concentration approximately 10 times higher than that of pure water can be obtained. Therefore, it shows much stronger pollutant removal capacity than ozone water. The removal treatment may be immersion in this ozone solution, but it is preferable to use an organic solvent having a very small surface tension of 30 dyn / cm or less for treatment with the liquid film. The liquid easily spreads in the form of a film on the entire surface of the object. Here, when the liquid moves, the surface contaminants acted on by the liquid also move at the same time, and efficient removal progresses. Also, the fine particles caught by the attached organic matter are easily removed because the organic matter dissolves in the liquid having a small surface tension and the liquid moves.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0051

[Correction method] Change

[Correction contents]

With respect to the sample (1) of the 800 nm resist film shown in Example 2 and the sample (4) ashed after ion implantation, the resist was stripped by this apparatus. In each case, the rotational speed of the wafer was 100 rpm, and ozone gas having an ozone concentration of 200 mg / L was supplied at 2 L / min. From the acetic acid introduction tube 61,
200 ppm or more of ozone acetic acid prepared in an ozone absorbing container similar to that shown in Example 3 was introduced into the center, and when the entire surface of the wafer was wet, about 80 drops were dropped in one minute. After this 2
After spin-rinsing by flowing ultrapure water for 0 seconds, the introduction of ozone was stopped, and the wafer was spin-dried at 4000 rpm.
Ultraviolet irradiation was performed at 00 rpm for 1 minute. As a result of charged particle activation analysis of the wafer, residual organic carbon was 3 and 5 × 10 ¹²
At atoms / cm ^{2 both} the resist and the methyl silicon layer were sufficiently removed.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0052

[Correction method] Change

[Correction contents]

[Embodiment 8] In the apparatus of FIG. 4 used in the previous embodiment, the chamber lid 53 is simply provided with the function of a lid without providing a low-pressure mercury lamp. An acid inlet tube was added. 800n shown in Example 2
m resist film (1) after the ozone acetic acid treatment and pure water rinsing in the same manner as in the previous examples for samples, dilute hydrofluoric acid (hydrofluoric acid: water -1 vol: 50 vol) rinses 15 seconds, deionized water After rinsing for 15 seconds, spin drying was performed as in the previous example. The residual carbon content is 1 × 10 ¹³ atoms / cm ^2, which is slightly higher than that of the previous embodiment, but the adsorbed molecules which can be sufficiently used in device manufacture are removed.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0060

[Correction method] Change

[Correction contents]

The wafer 55 to be processed in the single-wafer spin processing is configured such that the support member 55 is driven by a rotation mechanism 76 by a spin rotation shaft 51 and spins.
Chamber 5 for collecting the processing liquid scattered during spin processing
It is surrounded by two. This single-wafer processing mechanism and a support table 7 for a wafer cassette 77 for accommodating all of the wafers to be processed.
8 and a transfer robot 79 for automatically loading and unloading wafers between the cassette and the supporting member 55.
0 is provided. It should be noted that a mechanism is provided for automatically opening a part 81 of the wall surface of the chamber when the wafer enters and exits. A processing liquid supply pipe 83 having a nozzle 82 for discharging ozone acetic acid on the surface of the wafer at a terminal thereof,
An acetic acid supply pipe 85 having a nozzle 84 for discharging acetic acid for rinsing at the end thereof penetrates. Incidentally, these two supply pipes can be integrated into one by a valve operation.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0061

[Correction method] Change

[Correction contents]

A liquid discharge pipe 86 for discharging acetic acid collected at the bottom of the chamber, a gas introduction pipe 87 for replacing the atmosphere in the housing, and an ozone decomposer (not shown) using a catalyst such as Mn. ) And the ozone exhaust pipe 37 that passes through the housing wall surface. The housing is provided with an openable / closable door 6 for taking a wafer cassette in and out, and opens and closes only when ozone and acetic acid are discharged from the atmosphere in the housing. The ozone acetic acid solution can be prepared by feeding ozone gas to the acetic acid 88 stored in the ozone absorbing container 42 to the ozone radiator 89 of the quartz glass filter through the pipe 59 through the valve 58. Normally, a saturated ozone concentration is almost reached by 5 minutes of ventilation. This liquid is supplied to the nozzle 82 by the supply pipe 83 for a predetermined time through a Teflon liquid supply pump indicated by P and a precision filter for dust indicated by F. The supply of acetic acid to the ozone absorbing container and the discharge from the container are performed by a pipe 91 having a valve 90. Acetic acid 92 for rinsing is supplied to another container 93 through a pipe 95 having a valve 94. The rinsing liquid is sent to the rinsing nozzle 84 for a predetermined time by a pipe 85 passing through a liquid sending pump and a dust precision filter.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0062

[Correction method] Change

[Correction contents]

As described above, HMDS was applied to a 6 ″ wafer having a 100 nm oxide film to form a 1.5 μm film of photoresist IX555, and 25 films baked at 140 ° C. for 60 seconds were prepared. About 300 mL of acetic acid was placed in the ozone absorption container 42 and nitrogen-containing oxygen having an ozone concentration of 220 mg / L was bubbled from the ozone diffuser at a flow rate of 1 L / min. The maximum concentration reaches 380 mg / L per minute.The wafer 56 is rotated at 1000 rpm and the ozone acetic acid is discharged from the nozzle 82 at a speed of 1.5 mL / second. further continued only 20 seconds release of acetic acid in acetic acid container 93 was 10 seconds rinsed at a rate of 1.5 mL / sec from a nozzle 84, the rotation of the wafer 400 After rotating to 30 rpm for 30 seconds, the wafer was replaced with a wafer in a cassette and processed continuously for 25 wafers. About 15 seconds remained the same until the end.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/304 643 H01L 21/304 647A 647 21/30 572B 21/306 21/306 R F-term (Reference) 2H096 AA25 AA27 CA01 LA02 LA03 3B116 AA02 AA03 AB44 BB02 BB89 3B201 AA02 AA03 AB01 AB44 BB03 BB04 BB89 BB93 BB96 BB98 CC01 CC13 CC21 CD22 5F043 AA40 BB27 DD08 DD13 DD30 EE07 EE08 046

Claims (19)

[Claims] 1. The method according to claim 1, further comprising the step of:
A surface-attached contaminant characterized by removing a contaminant adhering to the surface of an object to be processed by contacting a processing solution in which ozone is dissolved in an organic solvent having a distribution coefficient of 0.6 or more with ozone in a gas. Removal method. 2. The surface of the object to which the contaminant adheres,
Forming a liquid film of the processing liquid, and supplying the new processing liquid to the liquid film continuously or intermittently to move the liquid film, thereby bringing the surface of the processing object into contact with the ozone-containing processing liquid; The method for removing contaminants adhering to a surface according to claim 1, characterized in that: 3. A liquid film of the organic solvent is formed on the surface of the object to which the contaminant adheres in an atmosphere containing ozone, and a new solvent is continuously or intermittently supplied to the liquid film. 2. The method for removing contaminants adhering to a surface according to claim 1, wherein the surface of the object to be treated is brought into contact with the ozone-containing treatment solution by moving the film solution. 4. The method according to claim 2, wherein the supply of the processing liquid or the organic solvent is performed by spraying. 5. An ozone-containing organic solvent liquid after the contaminant removal treatment is returned to a container of the organic solvent for dissolving ozone in the organic solvent, and circulated as a treatment liquid for treating another object to be treated. The method for removing contaminants adhering to a surface according to any one of claims 1 to 4, wherein the method is used. 6. The contaminant adhering to a surface according to claim 3, wherein the supply of the organic solvent liquid is performed by condensing the vapor generated from the heated liquid on the cooled surface of the object to be processed. Removal method. 7. The organic solvent of the formula: C _n H _{2n + 1} (COO
H) The method for removing contaminants adhering to a surface according to claims 1 to 6, wherein the fatty acid is a fatty acid represented by [n = an integer of 1, 2 or 3]. 8. The method according to claim 7, wherein water containing 5% by volume or less of an inorganic acid is added to the organic solvent comprising the fatty acid. 9. The method according to claim 7, wherein the organic solvent comprising the fatty acid contains 15 to 30% by volume of water. 10. The method according to claim 1, wherein the organic solvent is dichloromethane. 11. A container for preparing a treatment liquid by bubbling a gas containing ozone and dissolving the ozone in an organic solvent having a distribution coefficient of 0.6 or more with ozone in the gas; A pipe for transporting into a processing chamber having a; a mechanism for forming a liquid film of the processing liquid on the entire processing surface of the processing object to which the contaminant adheres in the chamber and moving the liquid of the film; A pipe for returning the liquid that has reached the bottom of the chamber after the processing to the container, for removing contaminants adhering to the surface of the object to be processed. 12. A chamber having an inlet and an outlet for a gas containing ozone, and the distribution coefficient of ozone in the gas over the entire processing surface of the object to be processed held in the chamber is 0.6.
An apparatus for removing contaminants adhering to the surface of an object to be processed, comprising a mechanism for forming a liquid film of an organic solvent and moving the liquid of the film. 13. The sprayer according to claim 11, wherein the mechanism for forming the liquid film is a sprayer that is provided above or to the side of the object held in the chamber and that operates continuously or intermittently. Or the apparatus for removing contaminants adhering to the surface of an object to be processed according to item 12. 14. A mechanism for forming a liquid film of the organic solvent on the surface of the object to be processed and moving the liquid in a film form, wherein the organic solvent reservoir provided below the object to be processed held in the chamber. 13. The apparatus for removing contaminants adhering to the surface of an object to be processed according to claim 12, wherein the apparatus is a steam cleaning mechanism including a heater for the liquid and a cooler provided on a side of the object to be processed. 15. A partition coefficient with ozone in a gas is 0.6.
A mechanism for forming a liquid film of the processing liquid in which ozone is dissolved in an organic solvent on the surface of the processing object and moving the film-like liquid holds the plate-shaped processing object substantially horizontally in the chamber. And a mechanism for discharging the solvent to the plate surface. A device for removing contaminants adhering to the surface of a plate-shaped object to be processed. 16. The formula: C in which ozone is dissolved in an amount of 100 ppm or more.
_n H _{2n + 1} (COOH) [n = 1, 2 or an integer of 3] A mechanism for supplying a fixed amount of a treatment liquid composed of a fatty acid, a tip nozzle of the supply liquid transport pipe and a waste liquid discharge pipe A chamber provided with an exhaust gas introduction pipe, an exhaust pipe thereof, and an openable and closable doorway for entering and exiting an object to be processed, and a liquid supplied from the nozzle by rotating the object to be processed in the chamber to generate a centrifugal force. An apparatus for removing contaminants adhering to the surface of a plate-shaped object to be processed, comprising: a mechanism for forming a liquid film by using the apparatus; and a mechanism for transporting the object to be processed. 17. The formula: C _n H _{2n + 1} (COOH), wherein n is an integer of 1, 2, or 3, which dissolves at least 150 ppm of ozone, optionally at least 200 ppm, and contains 15 to 30% by volume of water. A mechanism for supplying a fixed amount of fatty acid represented by the formula: , A mechanism for rotating a plate to be processed in the chamber to form a liquid film by centrifugal force by the liquid supplied from the nozzle, and a transport mechanism for the object to be processed. An apparatus for removing contaminants adhering to the surface of a plate-like workpiece. 18. The apparatus according to claim 15, wherein a mechanism for irradiating ultraviolet rays to the surface of the plate-shaped workpiece through a synthetic quartz glass plate is added in the chamber. Removal device. 19. A partition coefficient with ozone in a gas is 0.6.
A cleaning agent for removing pollutants, characterized by dissolving ozone in the organic solvent described above.