JP2951862B2 - Cleaning method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning method applicable to fields requiring precise cleaning of electronic parts and optical parts.

[0002]

Technical Background of the Invention and Problems Thereof Conventionally, chlorofluorocarbon has been frequently used for cleaning electronic components such as semiconductors and mounting substrates and optical components such as lenses, but fluorocarbon has problems such as destruction of the ozone layer. Was. Therefore, various studies have been made on a cleaning agent and a cleaning method that substitute for CFCs, and in recent years, cleaning has been carried out with an aqueous cleaning agent, especially in fields requiring precise cleaning such as semiconductors and liquid crystal color filters, and then alcohol has been used. Cleaning methods of performing steam drying with a hydrophilic organic solvent such as described above have come to be implemented. However, in the cleaning method of performing steam drying with a hydrophilic organic solvent after performing the above-described cleaning with an aqueous cleaning agent, a solvent attack, that is, plastic parts or the like, is performed due to exposure to high-temperature organic solvent vapor near the boiling point. In addition to problems such as whitening and cracking of the resin film, and a large amount of heat of condensation, the amount of condensate generated on the surface of the object to be cleaned is small, so cleaning is likely to be insufficient, and hydrophilic properties such as alcohol Since the solvent easily dissolves water, there is a problem that residue (stain) is easily generated on the object to be cleaned.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a cleaning method capable of washing without causing whitening or cracking of a plastic part or a resin film and without causing stains. Aim.

[0004]

The present inventors have conducted intensive studies to achieve the above object. As a result, the object to be cleaned is washed with a water-based cleaning agent and then rinsed with water, preferably pure water, to obtain a hydrophilic solvent. In the washing method of performing steam drying with a volatile organosiloxane after draining with, using a specific combination of a hydrophilic solvent and a volatile organosiloxane, specifically, as a volatile organosiloxane It has been found that it is effective to select and use a solvent having a boiling point of less than 160 ° C. and a boiling point of a hydrophilic solvent or, in the case of azeotropic boiling, at least 15 ° C. higher than its azeotropic temperature,
We have filed a patent application earlier (Japanese Patent Application No. 6-319647).
According to this method, it is possible to obtain a good cleaning property for a general material to be cleaned. When cleaning a large amount of material to be washed into the tank or cleaning a large amount of material in a short time, a large amount of hydrophilic solvent is brought into the steam drying tank in a short time. It was found that volatilization and removal could not be performed well, and there was a problem that solvent attack and spots were likely to occur.
Therefore, the present inventors further studied, and as a result, the object to be washed was washed with a water-based detergent, then rinsed with water, preferably pure water, drained with a hydrophilic solvent, and then with a volatile organosiloxane. In the washing method of performing steam drying, use a volatile organosiloxane having a boiling point of less than 160 ° C and a boiling point of the hydrophilic solvent (c) or at least 15 ° C higher than the azeotropic temperature in the case of azeotropic boiling. In the above-mentioned washing method, it was found that the above-mentioned problem can be solved by further providing a step of rinsing with a volatile organosiloxane between the step of draining with a hydrophilic solvent and the step of steam drying with a volatile organosiloxane. The invention has been completed. That is, the present invention aims at removing dirt components adhering to the object to be washed, (1) (a) a step of washing with a water-based detergent (2) (b) a step of rinsing with water (3) ( c) Step of draining with a hydrophilic solvent (4) (d) Step of rinsing with a volatile organosiloxane (5) Step of steam drying with a volatile organosiloxane of the same type as (d) above A cleaning method that performs sequential processing,
As the volatile organosiloxane (d), the boiling point is 160 ° C.
The washing method is characterized by using a solvent having a boiling point of less than or less than (c) a boiling point or an azeotropic temperature of at least 15 ° C. higher than the azeotropic temperature.

Hereinafter, the cleaning method of the present invention will be described step by step. In the present invention, first, as a step (1), dirt components adhering to an object to be washed are washed with an aqueous detergent. Examples of objects to be washed include electronic components such as semiconductors and mounting boards, and optical components such as lenses.The materials include glass and plastic, and especially plastic parts as described below. It is preferable to use a component having the resin component or a component provided with a resin film. As the aqueous detergent (a) used in the step (1), an aqueous solution of a surfactant is generally used. The type of the surfactant is not particularly limited, and a nonionic surfactant, an anionic surfactant, a cationic surfactant,
Any of the amphoteric surfactants may be used. Specific examples include glycerin fatty acid ester, sorbitan fatty acid ester, sucrose fatty acid ester, polyoxyethylene (hereinafter referred to as POE) alcohol ether, POE alkylphenol ether, POE fatty acid ester, POE glycerin fatty acid ester, POE sorbitan fatty acid ester, POE Nonionic surfactants such as fatty acid amide, POE / polyoxypropylene (hereinafter referred to as POP) block copolymers; sodium alkylbenzene sulfonate, sodium alkyl POE sulfonate, sodium alkylbenzene POE sulfonate, sodium glycerin fatty acid monoester sodium phosphate Anionic surfactants such as tetraalkylammonium chloride,
Examples include cationic surfactants such as trimethylbenzylammonium chloride; amphoteric surfactants such as alkylaminoalkanoic acid and trialkylaminomaleic acid. The cleaning method is not particularly limited, and any method such as immersion, immersion rocking, immersion ultrasonic cleaning, and shower cleaning may be used. The cleaning with the aqueous cleaning agent may be performed in only one tank, or may be performed in a plurality of tanks.

[0006] Next, in the step (2), rinsing with the water of the step (b) is performed to remove the surfactant and the like, which are components of the water-based detergent remaining on the article to be washed. As the water in (b), it is preferable to use pure water. The rinsing according to (b) may be performed in only one tank or in multiple tanks. However, if particularly precise cleaning is required, use multiple tanks and use pure water from which suspended particulates and ionic components have been removed. Is preferably used in at least the final rinsing tank. The rinsing method is not particularly limited, and any method such as immersion, immersion rocking, immersion ultrasonic rinsing, and shower rinsing may be used. If drying is attempted at the stage of rinsing with water or pure water, the evaporation rate is slow and not only takes time to dry, but also stains easily occur, so the hydrophilic solvent of (c) is used as the next step (3). To remove water from the surface of the object to be washed, that is, to drain water. The draining method is not particularly limited, and any method such as immersion, immersion rocking, immersion ultrasonic cleaning, and showering may be used. If you try to dry after draining with a hydrophilic solvent,
A hydrophilic solvent generally has a large surface tension and thus is easily condensed. Further, since the heat of evaporation is large, not only time is required for drying but also stains are easily generated. Therefore, in the next step, when the vapor drying is performed with the volatile organosiloxane (d), as described above, the amount of the hydrophilic solvent (c) brought into the tank in the next step due to the complicated shape, etc. When cleaning a large amount of material to be cleaned or a large amount of material to be cleaned in a short period of time, a large amount of hydrophilic solvent is brought into the steam drying tank in a short period of time, so that volatilization and removal cannot be performed successfully. ,
Therefore, the occurrence of solvent attack and spots cannot be completely prevented. Therefore, in the present invention, before steam drying,
By providing the step (4), ie, the step (d) of rinsing with the volatile organosiloxane, the amount of the hydrophilic solvent (c) brought into the steam drying step (5) is reduced. The method of rinsing with the volatile organosiloxane (d) in the step (4) is not particularly limited, and any method such as immersion, immersion rocking, immersion ultrasonic rinsing, or shower rinsing may be used. The step (4) may be performed in only one tank, or may be performed in a plurality of tanks. By providing a plurality of tanks, it is possible to perform good cleaning without a solvent attack or a stain which is a feature of the present invention. it can.

Finally, the washing is completed in the step (5), that is, the step of performing steam drying with the same kind of volatile organosiloxane as the above (d). At this time, (c) adhering to the article to be washed is (C) By being washed off by the condensate of d), (c) is introduced into (d) as the number of washings increases. The volatile organosiloxane (d) has good wet-spreadability and a high drying rate, and does not cause solvent attack on the plastic even at the condensation temperature.However, the hydrophilic solvent (c) cannot be used at such a high temperature. It causes solvent attack on the plastic, and has poor wet-spreading properties and a low drying speed, so that stains are easily generated on the object to be washed. Therefore, as described above, if (c) brought into (d) accumulates in (d), solvent cracks and spots are likely to occur.

In the present invention, in order to prevent these problems, (c) and (d) are selected so as to satisfy the following conditions. That is, when the volatile organosiloxane (d) has a boiling point of less than 160 ° C., preferably less than 110 ° C. and azeotropes with the boiling point of the hydrophilic solvent of (c) or the hydrophilic solvent of (c), The above problem can be prevented by selecting a material having a temperature higher than the azeotropic temperature by 15 ° C. or more, preferably by 20 ° C. or more.
This temperature difference preferentially volatilizes the hydrophilic solvent of (c) during the steam cleaning and causes the volatile organosiloxane of (d) to evaporate.
(c) is the temperature difference required to prevent accumulation. If the temperature difference is smaller than this, as described above, if (c) and (d) accumulate in (d) with the continuation of the steam drying operation, solvent attack and spots are likely to occur. And the boiling point of (d) is 16
The reason why the boiling point is lower than 0 ° C., preferably lower than 110 ° C. is that if the boiling point is higher than this, plastic parts may be softened and deformed during steam drying or parts that are vulnerable to thermal shock such as glass may be damaged.

The hydrophilic solvent (c) is not particularly limited, but has a high hydrophilicity and excellent drainability, and
Alcohol solvents such as methanol, ethanol and isopropyl alcohol are recommended because of excellent compatibility with the volatile organosiloxane (d). (D)
Examples of the volatile organosiloxanes include hexamethyldisiloxane and octamethyltrisiloxane in the sense of satisfying the boiling point of less than 160 ° C, preferably less than 110 ° C, and hexamethyldisiloxane is particularly preferred. The following are examples of combinations of these (c) and (d). Hexamethyldisiloxane (boiling point; 100 ° C) and methanol (azeotrope with hexamethyldisiloxane at 58.7 ° C), hexamethyldisiloxane and ethanol (boiling point;
78 ° C), hexamethyldisiloxane and isopropyl alcohol (azeotrope with hexamethyldisiloxane at 76.4 ° C),
Octamethyltrisiloxane (boiling point: 149 ° C) and methanol, octamethyltrisiloxane and ethanol, octamethyltrisiloxane and isopropyl alcohol.

In the present invention, even if the washing is continued, the hydrophilic solvent of (c) does not accumulate in the volatile organosiloxane of (d) in the steam washing tank used in the step (5).
It is not necessary to replace or regenerate (d) in the steam cleaning tank, and it is only necessary to add consumption. Since the hydrophilic solvent of (c) is carried into the volatile organosiloxane of (d) in the rinsing tank used in the step (4), it is preferable to periodically exchange and regenerate the liquid.

[0011]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. Examples 1 to 2 and Comparative Examples 1 to 3 A 10 cm × 10 cm glass plate coated with an acrylic photoresist agent was used as a test specimen, and ten sheets were placed in a net basket. After rinsing with water, rinsing was performed with tap water and then with pure water. Next, after draining with the hydrophilic solvent shown in Table 1, rinsing with the volatile organosiloxane shown in Table 1 was performed, and steam drying was performed for one minute in the steam drying tank shown in FIG. 2 using the same volatile organosiloxane. Was done. Observation of the surface condition of the test specimen after the initial cleaning and after repeating the cleaning 10 times and 100 times, and analyzing the liquid composition in the steam drying tank by gas chromatography to determine the draining agent brought in from the draining tank Table 1 also shows the measurement results of the accumulated amount. Comparative Example 1 is a comparative example in which steam drying was directly performed after draining, and Comparative Example 2 is a relationship between the boiling point of the hydrophilic solvent used in draining and the boiling point of the volatile organosiloxane used in steam drying. Comparative Example 3 and Comparative Example 3 are comparative examples in which isopropyl alcohol was used instead of volatile organosiloxane as a steam drying agent. FIG. 1 is a schematic diagram of the cleaning step of this embodiment, and FIG. 2 shows a steam drying tank used for steam drying of a volatile organosiloxane.

Examples 3 to 5 and Comparative Examples 4 to 6 A 10 cm × 10 cm glass plate coated with an epoxy resin was used as a test specimen, and ten sheets were placed in a net basket and washed with an aqueous detergent shown in Table 2. After that, they were rinsed with tap water and then with pure water. Next, after draining with a hydrophilic solvent also shown in Table 2, rinsing with a volatile organosiloxane shown in Table 2 was performed, and steam drying was performed for 1 minute in the steam drying tank shown in FIG. 2 with the same volatile organosiloxane. Was done. Observation of the surface condition of the test specimen after the initial cleaning and after repeating the cleaning 10 times and 100 times, and analyzing the liquid composition in the steam drying tank by gas chromatography to determine the draining agent brought in from the draining tank Table 2 shows the measurement results of the accumulated amount.
Shown in Comparative Example 4 is a comparative example in which steam drying was performed directly after draining, and Comparative Example 5 shows the relationship between the boiling point of the hydrophilic solvent used in draining and the boiling point of the volatile organosiloxane used in steam drying. Comparative Example 6 and Comparative Example 6 are comparative examples using isopropyl alcohol instead of volatile organosiloxane as a steam drying agent. Note that the washing process is the same as in Examples 1 and 2.

[0013]

[Table 1]

[0014]

[Table 2]

[0015]

As described above, according to the cleaning method of the present invention, it is intended to clean a large amount of the material to be cleaned brought into the tank in the next step or to clean a large amount of the material in a short time. Even in this case, it is possible to perform cleaning without leaving stains on the material to be cleaned, and without causing solvent attack on the plastic material or the material to be cleaned coated with a resin film.

[Brief description of the drawings]

FIG. 1 is a view schematically showing a cleaning step in an embodiment of the present invention.

FIG. 2 is a schematic view showing a steam drying tank used in an example.

[Explanation of Signs] 1 ... Steam desiccant (100ml) 2 ... Glass container (cylindrical) 3 ... Chiller (3mm inside diameter steel pipe, refrigerant 5 ° C water) 4 ... Steam phase 5 ... Heating device

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Shigeo Yamafuji 6-2-31 Roppongi, Minato-ku, Tokyo Toshiba Silicone Co., Ltd. (56) References JP-A-8-173919 (JP, A) JP-A-7 -265817 (JP, A) JP-A-4-124289 (JP, A) JP-A-6-238244 (JP, A) JP-A-7-179897 (JP, A) JP-A-6-134444 (JP, A) ) Patent 2723359 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) B08B 3/08

Claims (2)

(57) [Claims] (1) (1) (a) a step of washing with a water-based cleaning agent (2) (b) a step of rinsing with water (3) ( c) Step of draining with a hydrophilic solvent (4) (d) Step of rinsing with a volatile organosiloxane (5) Step of steam drying with a volatile organosiloxane of the same type as (d) above A cleaning method that performs sequential processing,
As the volatile organosiloxane (d), the boiling point is 160 ° C.
A washing method characterized by using a solvent having a boiling point or an azeotrope of at least 15 ° C. higher than the azeotropic temperature of the hydrophilic solvent (c). 2. The volatile organosiloxane of (d) having a boiling point of less than 110 ° C. and a boiling point of the hydrophilic solvent in the step (c) or, in the case of azeotropic boiling, at least 20 ° C. higher than its azeotropic temperature. The cleaning method according to claim 1, wherein