JP3521136B2 - Cleaning method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning method and a cleaning apparatus for cleaning objects to be cleaned such as optical parts and electronic parts. 2. Description of the Related Art Conventionally, for example, in cleaning an optical element or the like, a cleaning system such as a non-aqueous solvent, a detergent, a hydrophilic solvent, and a fluorocarbon vapor is generally used. However, as is well known, CFCs have a significant impact on the environment, and are globally abolished. In recent years, various alternative methods of cleaning systems using chlorofluorocarbon have been proposed. Of which
As one possible alternative cleaning method, Patent International Publication No. W
There is a cleaning method disclosed in O 91/13697. In this cleaning method, in a first cleaning step, a basic cleaning agent based on a non-aqueous cleaning agent such as a low molecular weight siloxane or isoparaffin or a surfactant or a hydrophilic solvent is used as a drainer or a cleaning agent. A method is used in which a mixture with a cleaning performance improving agent is used, which is further immersed in a second cleaning step in a basic cleaning agent based on low molecular weight siloxane or isoparaffin and then dried. [0004] As a drying method, hot air drying at 60 ° C or less or vapor drying of perfluorocarbon is performed, and as ancillary equipment, specific gravity difference separation of water and oil in the cleaning liquid, separation of only the basic cleaning agent, and resupply. Proposing system. [0005] In the above prior art, in the first cleaning step (water draining / cleaning step),
The object to be cleaned is immersed in a non-aqueous solvent such as low molecular weight siloxane or isoparaffin or a mixture of these with a surfactant or a hydrophilic solvent. However, since the non-aqueous solvent hardly dissolves water and surfactant remaining on the object to be cleaned in the step before the first step, draining and cleaning cannot be performed effectively, and the non-aqueous solvent in the second cleaning is not used. The surface of the object to be cleaned, which has reached the cleaning step using the basic cleaning agent, is in a state where moisture or the like adheres. [0006] When moisture remains on the surface of the object to be cleaned, the drying method in the next step has no chemical dissolving power, so that water cannot be removed unless some physical force is applied. However, physical force is relatively less uniform than chemical dissolving power and is more susceptible to the conditions of hardware use. It is the current situation. In the case where a cleaning performance improving agent such as a surfactant is mixed in a non-aqueous solvent in the first cleaning step, rinsing the surfactant is required for the non-aqueous solvent in the second cleaning. It is very difficult in only the steps. That is, as a result, in both cases, residues composed of moisture and a surfactant are apt to remain on the surface of the object to be cleaned, and the use of the conventional method is unsuitable especially for cleaning in a field where appearance quality is a problem. Further, in the above prior art, since the drying temperature of the hot air drying is low, it is effective when the object to be cleaned is easily affected by the temperature, but on the other hand, there is a disadvantage that the drying time is uniformly required. there were. SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and a cleaning method capable of obtaining the best cleaning quality of an object to be cleaned without leaving the residue and without requiring a drying time. The aim is to provide a method. [0011] In order to solve the above-mentioned problems, the invention according to claim 1 is a method for cleaning an object to be cleaned such as an optical component or an electronic component. A step of immersing the object to be cleaned in a non-aqueous solvent that is at least one selected from a low molecular weight polyorganosiloxane selected from an organosiloxane and a cyclic polydiorganosiloxane, and using a non-aqueous solvent of the same type as the non-aqueous solvent. Decompression
And a step of vapor drying . The linear polydiorganosiloxane is preferably, for example, octamethyltrisiloxane, hexamethyldisiloxane or decamethyltetrasiloxane, and the cyclic polydiorganosiloxane is, for example, octamethylcyclotetrasiloxane. Decamethylcyclopentasiloxane is preferred. The object to be washed is a highly dry linear polydiorgan.
From polysiloxanes and cyclic polydiorganosiloxanes
Selected from selected low molecular weight polyorganosiloxanes
Immersed in at least one type of non-aqueous solvent , and the residue of the water or surfactant in the previous step remaining on the surface of the object to be cleaned is replaced with a non-aqueous solvent. The processing is performed by a cleaning line that lifts and finally vapor-cleans and dries. In this cleaning method, since vapor cleaning and drying are applied to the final finishing step, compared to a series of methods such as immersion pulling up and hot air drying, a cleaning sample having a complicated shape with a large amount of liquid residue is removed. However, the desired cleaning quality can be satisfied, and the cleaning finish quality can be improved. Further, since the cleaning and drying are performed by vapor, even if the non-aqueous solvent used as the vapor is contaminated, the non-aqueous solvent liquid that condenses and adheres to the surface of the object to be cleaned as a vapor and performs the cleaning action is removed by distillation. As clean as the liquid
Then, the danger of ignition is reduced by the vapor under reduced pressure, and the vapor becomes safe, and cleaning with a clean liquid is performed. For example, when the present invention is applied to cleaning of an optical element, an abrasive, a centering oil, a fingerprint and the like are removed in a degreasing step using an aqueous cleaning agent or a semi-aqueous cleaning agent, and then the cleaning agent using water or pure water. Is washed and rinsed, and then water is replaced (dehydrated) with IPA as a solvent that rapidly dissolves water.
After the replacement of PA, cleaning and drying with a vapor of a non -aqueous solvent of the same type as the non -aqueous solvent in the previous step are finally performed under reduced pressure. In this case, by using IPA as a solvent for rapidly dissolving water in a step before the step of immersing the optical element in the non-aqueous solvent having a high drying property, the optical element adheres to the surface of the object to be cleaned. The obtained water is immediately dissolved by the IPA, and is uniformly dissolved and dispersed in the solvent liquid. Therefore, even if an object to be cleaned is washed or rinsed with water or pure water and immersed in IPA as a solvent for rapidly dissolving water, residual water on the surface to be cleaned is dissolved and dispersed in the IPA, so that there is no water. When immersed in a non-aqueous solvent, the IPA on the surface is completely replaced by the non-aqueous solvent, so that the surface is uniformly wetted. In this state, when the object to be cleaned is lifted and the vapor is cleaned and dried, no stains due to residual moisture on the surface to be cleaned are eliminated, and good cleaning quality can be obtained. For the regeneration of the non-aqueous solvent used as the final finishing liquid, a water separator utilizing the difference in solubility and specific gravity with water and IPA is used. The exhaust gas and the waste liquid after the drying under reduced pressure vapor are passed through a water tank while being cooled.
The IPA used in the previous dehydration step is dissolved in water, but the non-aqueous solvent used for vapor drying is insoluble in water.
Separation occurs in the lower layer of water in which A is dissolved, and as a result, only the non-aqueous solvent can be taken out. By sending the non-aqueous solvent to the vapor tank, repeated use becomes possible. The IPA in the dehydration step is controlled so that the amount of water dissolved is always 10% by weight or less (preferably 5% by weight or less). It is completely removed by passing it through a separator. Therefore, such a reproducing method is a good reproducing method having an extremely low IPA content. Example 1 A cleaning step as shown in FIG. 1 was set and cleaning was performed. In FIG. 1, part A is a degreasing step (first step), part B is a washing / rinsing step (second step), part C is a dehydration step (third step), and part D is a solvent solution for dissolving water. The replacement step (fourth step) between IPA and the non-aqueous solvent and the vapor cleaning / drying step (fifth step). The cleaning apparatus of this embodiment has 11 treatment tanks 1
The first and second treatment tanks 1 are provided with a surfactant 2 as an aqueous cleaning solution (Olympus Chemical Tech Co., Ltd.).
Aqueous cleaning solution; EE-1110), and an alkaline surfactant 3 (Olympus Chemical Tech Co., Ltd., aqueous cleaning solution; EE-112) in the third and fourth treatment tanks 1.
0), pure water 4 is poured into the fifth to seventh treatment tanks 1, IPA 5 is placed in the eighth and ninth treatment tanks 1, and low-molecular-weight polysiloxane 6 ( Olympus Chemtech Co., Ltd., non-aqueous cleaning solution; EE-3110) was added. The eleventh processing tank 1 is a reduced-pressure vapor machine for performing vapor cleaning and drying of the low-molecular-weight polysiloxane 6 under reduced pressure. The low-molecular-weight polysiloxane 6 used was composed mainly of octamethyltrisiloxane. Ultrasonic vibrators 7 are all disposed at the bottom of the first to ninth treatment tanks 1, and a closed pump 8 is provided except for the tank containing pure water 4.
An overflow circulating tank (indicated by the symbol P) was used. The symbol F indicated by 9 is a filter. In particular, the first
In the treatment tank 1 of No. 0, an IPA separator 10 was interposed in the circulation process to separate the brought-in IPA 5 (lower layer) from the low-molecular-weight polysiloxane 6 and regenerate only the low-molecular-weight polysiloxane 6. The frequency and output of the ultrasonic wave are 40 KHz and 600 W, and the flow rate of the overflow is 5 ml / m
in. An optical lens was used as an object to be cleaned (cleaning sample) 11, and this was quickly cleaned by a three-point support basket attached to the tip of a swing arm 12. The three-point support basket is shown in FIGS. This basket supports the object 11 to be cleaned soon after the rod-shaped SUS frame 13 comes into contact with the outer periphery of the object 11 to be cleaned from three places. In order to prevent this, a serrated fixing member (Teflon (registered trademark) claw) 14 is provided. In this embodiment, the number of cleaning lenses per basket was set to 60. Further, as described above, the eleventh treatment tank 1
As shown in FIG. 1, it is a reduced-pressure vapor machine, and is provided with a reduced-pressure drying tank 15 and a vapor generator 16 so that vapor cleaning and drying can be performed under reduced pressure of the low-molecular-weight polysiloxane 6. A collection tank 17 and a recycling tank 18 are interposed between the reduced-pressure drying tank 15 and the vapor generator 16 so that the low-molecular-weight polysiloxane 6 is recycled by the pump 8 and the filter 9. In the present embodiment, the swinging speed of the swinging arm 12 was 2 S / 50 mm reciprocating stroke, and the washing time was 1 min for each bath. The reduced pressure vapor conditions include a degree of vacuum of 100 Torr, a reduced pressure time of 1 min, and a steam feed time of 1 minute.
0 sec, scavenging time 15 sec, solvent vapor temperature 1
It was set at 40 ° C. After washing in the above washing step, visual evaluation under a fluorescent lamp was performed after washing, coating and resistance.
Table 1 shows the results. According to this example, the cleaning quality was at a good level. [Table 1] In order to verify the effects of the present invention in comparison with the above-mentioned conventional technology, the conventional technology was implemented. In the conventional technology, most lenses (objects to be cleaned) were stained. Oops. Hereinafter, a first modification in which the steps after degreasing with an aqueous cleaning agent are the same as the steps according to the first embodiment will be described. Specifically, after performing the first step which is primary degreasing with a non-aqueous solvent or a semi-aqueous solvent, the second step which is secondary degreasing with an aqueous cleaning agent is performed, and then water or pure water is used. The third step of washing and rinsing the second step liquid is performed, and the fourth step of water rinsing by IPA is performed.
After that, a fifth step of replacing the IPA with a non-aqueous solvent to clean the object to be cleaned is performed, and a cleaning method and apparatus including a sixth step of performing vapor cleaning and drying of the non-aqueous solvent under reduced pressure will be described. . This cleaning method is an effective method as a cleaning step for removing a pitch remaining after polishing of an optical element or a resin-based protective film applied for a subsequent step. The solid pitch, resin and the like adhering to the lens and the like cannot be degreased only by the washing step of the aqueous detergent, and the degreasing step using a non-aqueous or semi-aqueous solvent is indispensable. This washing process is dissolution rather than emulsification. Compatibility is achieved by utilizing the properties of a solvent having the same solubility parameter as the object to be cleaned. In the next step, a series of washing steps such as replacement of water, replacement of IPA with a non-aqueous solvent having high drying properties, and drying under reduced pressure vapor are taken. That is, the steps after the aqueous cleaning agent are the same as the steps of the embodiment of the invention according to the first embodiment,
The effect is the same. By performing this step, solid deposits such as pitch, fingerprints, abrasives, oil and the like can be removed at once, and the finished quality can be improved without stains. Next, a specific example in which this cleaning method is performed will be described with reference to FIG. A cleaning step as shown in FIG. 4 was set, and the cleaning was performed. The cleaning device is composed of 14 treatment tanks 1, and the first to third treatment tanks 1 each include an organic solvent 2.
2 (made by Olympus Chemitec Corporation, EE-411)
0), the fourth to seventh treatment tanks 1 contain an alkaline surfactant 3
(For example, the EE-1120), the eighth to tenth processing tanks 1
And pure water 4 is poured into the treatment tank 1, and
PA5 and the thirteenth and fourteenth processing tanks 1 were charged with low molecular weight polysiloxane 6 (for example, EE-3110). E
E-4110 is a non-aqueous terpene hydrocarbon solvent. In FIG. 4, part H is a primary degreasing step, part I is a secondary degreasing step, part J is a cleaning rinse step, part K is a draining step, and part L is a replacement of IPA and a vapor cleaning / drying step. As the low molecular weight polysiloxane 6, one containing octamethyltrisiloxane as a main component was used. All of the processing tanks 1 except the fourteenth tank are provided with ultrasonic vibrators 7.
In addition, a closed overflow circulation tank was used except for the processing tank 1 in which the pure water 4 was put. As a cleaning sample, the polished pitched lens was cleaned. Other cleaning conditions are the same as in the first embodiment. The washing was performed in each of the first to thirteenth tanks while applying ultrasonic waves in each tank for one minute. The lens was washed by the main washing step, and an anti-reflection coating was applied to the washed lens. In addition, as a drying process, a reduced-pressure vapor (EE-3110, a working liquid manufactured by Olympus Chemtech Co., Ltd.) was used. The conditions of the reduced pressure vapor were as follows: the degree of vacuum was 100 Torr, the reduced pressure time was 1 min, the vapor feed time was 10 sec, the scavenging time was 15 sec, and the vapor temperature of the low molecular weight polysiloxane 6 was set at 140 ° C. After the cleaning, the appearance was evaluated without any spots due to the pitch attached to the lens, and the results were good. The cleaning quality was equivalent to that of the conventional 14-tank-level trichlorene-CFC cleaning machine. Table 2 shows the results (as Modification Example 1). [Table 2] When low-molecular-weight polysiloxane 6 used octamethylsiloxane and decamethyltetrasiloxane in the final finishing step, the same experimental results were obtained, and the effect was confirmed. As described above, according to the cleaning method of the present invention, the final finish of the object to be cleaned is good without leaving any residue on the surface of the object to be cleaned and without increasing the drying time. To achieve a stable quality.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a process chart showing a cleaning method of Example 1. FIG. 2 is a plan view showing a basket used in the first embodiment. FIG. 3 is a side view showing the basket used in the first embodiment. FIG. 4 is a process chart showing a cleaning method according to a first modification of the first embodiment; [Description of Signs] 1 Treatment tank 2 Surfactant 3 Alkaline surfactant 4 Pure water 5 IPA 6 Low molecular weight polysiloxane 11 Object to be washed 22 Organic solvent

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-245451 (JP, A) JP-A-5-128595 (JP, A) JP-A-5-295577 (JP, A) International Publication No. 91/013697 (WO, A1) (58) Field surveyed (Int. Cl. ⁷ , DB name) B08B 1/00-7/04

Claims (1)

(57) [Claims 1] A non-aqueous solvent which is at least one selected from low molecular weight polyorganosiloxanes selected from linear polydiorganosiloxanes and cyclic polydiorganosiloxanes. immersing the said non
Vacuum vapor drying using non-aqueous solvent of the same kind as aqueous solvent
A cleaning method.