JPH03147325A - Drying of precision cleaning - Google Patents

Abstract

PURPOSE:To execute a cleaning and drying operation of an extremely high cleaning degree over the whole surface of a cleaned face without causing a stain or the like by a method wherein, after a work has been immersed in pure water and its cleaning operation has been finished, a pulling-up speed of the work is set to an ultralow speed when the work is pulled up from the pure water and the work and a drying gas at its periphery are heated to increase their temperature by using heat rays such as infrared rays or the like. CONSTITUTION:A work 1, as an object to be cleaned, which has been handed over from a precision cleaning operation in a previous stage by using a holder 11 is immersed in pure water 2 inside a pure-water cleaning tank 4; the work 1 is pulled up into a drying gas 3 vertically from the surface of the pure water 2 at an ultralow speed as far as possible. In a pulling-up process, the drying gas 3 is heated to increase its temperature by using infrared rays as heat rays which are radiated from infrared lamps 16, 16; also the work 1 is heated to increase its temperature and its drying operation is promoted; an ultraprecise drying operation is executed without producing a stain or the like on a cleaned face and without causing a disturbance by a spraying operation of the drying gas 3.

Description

[Detailed description of the invention] Production 5! ．． 12- Field of Application> The disclosed technology belongs to the technical field of ultra-precision cleaning of parts such as wafers of electronic devices, parts of optical lenses and glass cages.

<Summary of the gist> The invention of this application is to clean the object to be cleaned, which has been transported from the previous manufacturing process, etc., in a predetermined number of stages using a chemical solution or ultrasonic waves, and then clean it in a pure water cleaning tank. Relating to a drying method for precision cleaning in which finishing cleaning is performed with water, and the object to be cleaned is lifted from the pure water of the pure water cleaning tank into the drying gas at the upper part to remove the pure water adhering to the cleaning surface. This invention is particularly a method for lifting an object to be cleaned, which has been immersed in pure water in a pure water cleaning tank for final cleaning, from the surface of the pure water into the dry gas above at an extremely low speed vertically or the like. Precision cleaning is performed by emitting heat rays such as infrared rays onto the object to be cleaned using an infrared lamp or near-infrared lamp in a drying gas so that it can be instantly and quickly dried in the lifting process. This invention relates to a drying method.

<Prior art> As is well known, modern civil life and industrial society owe much to precision science and technology, and in particular to electronic equipment, electronically controlled mechanical devices, and optical equipment. The precision of equipment and optical equipment has become extremely demanding, and because of their precision, so-called IC parts and electronic optical parts do not allow dust to adhere to the product surface, and can be manufactured with micron-level precision. degree is required, therefore,
In the cleaning process at the final stage of the manufacturing process for these types of precision parts, ultra-precision cleaning at the submicron level is now required, going beyond precision cleaning at the micron level. BACKGROUND ART It has become essential to have a process in which a workpiece to be cleaned (hereinafter referred to as a workpiece) manufactured in a process is subjected to cleaning with a chemical solution or ultrasonic waves in the final cleaning process, and then turned into a product.

Problems to be Solved by the Invention> However, in the cleaning process in the United States, after the precision cleaning process, the object to be cleaned is immersed in pure water inside the pure water washing tank, and the cleaning process is carried out using the pure water. Final finishing cleaning (1 step - After cleaning, remove the object to be cleaned from the pure water, remove the pure water that adheres to the cleaning surface of the workpiece, and dry the air, cleaning gas, etc. in the F part. The spray is dry due to the gas.

However, both theoretically and practically, it is almost impossible to obtain 100% pure pure water and dry gas in the deionized water cleaning tank, and there is a very small amount of water in the submicron level. There are dust and residual chemical components from chemical cleaning in the previous process. Therefore, in the final cleaning process, the cleaning surface is If pure water adheres to the surface of the workpiece, the dust and chemical solution concentrated on the cleaning surface of the workpiece during the drying stage by blowing drying gas will remain as so-called stains, making it difficult to perform ultra-precision cleaning at submicron scale. The problem was that I couldn't make it come true.

<Object of the Invention> The object of the invention of this application is to solve the problem of ultra-precision cleaning in the final cleaning process in the manufacturing process of ultra-precision parts of electronic devices and optical products based on the above-mentioned conventional technology, and to conduct experiments. Through theoretical analysis of test results, etc., it is possible to almost completely prevent the adhesion of dust, etc. that would cause stains on the cleaning surface during the lifting process of a workpiece immersed in pure water in a pure water cleaning tank. In this way, it is an object of the present invention to provide an excellent precision cleaning drying method that is beneficial to the field of cleaning technology application in the ultra-precision parts manufacturing industry.

Means and Actions for Solving the Problems〉1 In order to solve the problems mentioned above, the structure of the present invention, which is summarized in the above-mentioned claims, is intended to solve the problems mentioned above. In the cleaning process that follows the manufacturing process of precision parts, etc., when finishing cleaning the workpiece after completing the predetermined number of stages of precision cleaning in the deionized water cleaning tank with pure water, the pure water in the deionized water cleaning tank A lateral laminar flow is applied to the water in advance,
Make sure to capture and filter any residual chemical solution from the previous stage of the pure water, and circulate the dry gas in the upper part at a predetermined low speed in the lateral and downward directions. J
3. Filter and capture dust up to the submicron level using a filter, etc., and turn on an infrared lamp, etc.
Heat rays such as infrared rays are radiated to the rising part of the workpiece, the workpiece is crushed there, and the workpiece after immersion is washed with pure water (when it is lifted from the negative pure water into the dry gas at the top). , raise the water perpendicularly to the water surface at the lowest speed possible, and apply pure water to the surface of the object to be cleaned in a thin film by the height created by the agglomerated horns and surface tension of the purified water, and The thin film of pure water that adheres to the cleaning surface adheres to the specified height, but the upper edge of the adhesion height immediately comes into contact with the drying gas, so it is pulled up at a very low speed. It dries instantly, and is further heated by heat rays such as infrared rays to speed up the drying speed as much as possible, removing dust and stains from the concentration effect of the previous chemical on the cleaning surface. We have taken technical measures to ensure that 1q of products with a cleaning surface that has been ultra-precisely cleaned and dried as designed can be produced without causing any problems.

<Background of the Invention> According to the experiments and tests conducted by the applicant, who is a person skilled in the art, although there are differences in the size of the cleaning surface of a workpiece immersed in pure water during final finishing cleaning, pure water If the blood adheres in the form of spots or blocks, that is, in the form of water droplets, dust or chemicals from the previous stage will adhere due to concentration during the drying process, but pure water adhering to the washed blood may form a thin film over a wide area. It has been found that when the material is in an adherent state, the adhesion of atom dust and chemical solution does not occur so much even when drying is performed using a drying gas due to the concentration effect.

Based on such data and results, as shown in FIG. 3 (the solid line in FIG. 3 is a hydrophilic aspect, and the opposite is shown in the dotted line in the case of hydrophobicity), for example, optical A glass plate 1 of a component workpiece is immersed in pure water 2 of a cleaning tank (not shown) in a finishing cleaning tank, and then pulled up into a dry gas 3 at the top at an ultra-low speed as close to zero as possible. When pulled up, due to the balance between the cohesive force and surface tension of the pure water 2, the cleaning surface 2 of the 9 objects 1 (to be washed) is connected to the drying gas 3 at the top, with a film of pure water 2 adhering to a height h. Therefore, when the object to be cleaned 1 is pulled up at an extremely low speed in the direction of the arrow, that is, perpendicularly to the water surface, the thin film of pure water 2 adhering to the surface to be cleaned rises above the predetermined height h. Therefore, when the object 1 to be cleaned is pulled up at an extremely low speed, the thin film of adhered pure water 2 immediately comes into contact with the drying gas 3 above the height h of the purified water 2, and the object 1 to be cleaned is pulled up. At extremely low speeds, the upper edge of the adhering pure water 2 dries instantaneously, preventing the adhesion of dust due to the shrinkage phenomenon and stains due to the residual chemical solution from the previous stage. It has been found that it is possible to obtain the object 1 to be cleaned, which has a surface to be cleaned that has been dried ultra-precisely on a submicron scale.

As mentioned above, this is due to the thin, wide-area water film part around the top of the height h of the adhering pure water on the cleaning surface of the object to be cleaned 1 due to the cohesive force and surface tension of the pure water. Further, near the top of the height h, the edge of the thin film of pure water immediately comes into contact with the drying gas 3, so that drying occurs instantaneously. I realized that it was something that would happen.

Therefore, according to this theory, spot-like or block-like water droplet-like adhesion 1i[! C: The theoretical analysis that water does not occur and therefore stains do not occur can be obtained.

Therefore, in the process of lifting the object 1 to be cleaned from the pure water 2, it is sufficient to perform a laminar flow of the pure water to the side.

Furthermore, by lighting an infrared lamp 16 or the like to emit infrared rays, near-infrared rays, etc., to the workpiece 1, the workpiece 1 and the drying gas in its vicinity are heated to the temperature of
It has also been found that the drying speed of pure water can be increased as much as possible.

<Embodiment> Next, an embodiment of the invention of this application will be described below with reference to FIG. 3 and according to FIGS. 1.2.

In the illustrated embodiment, reference numeral 4 denotes a pure water cleaning tank for finishing cleaning 2, in which predetermined pre-stage precision cleaning (a) of a plurality of predetermined stages (not shown) is shown.
Storage tanks 5 and 5' for circulating pure water 2 are provided on both front and rear sides of the tank, and the circulation pump 6, filter 7, and water are heated to a predetermined temperature. It has a heater 8 and is connected by a circulation circuit 9. Inside the tank body, there are perforated plates 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10. It is installed vertically and allows the pure water 2 to flow in a laminar flow in the lateral direction at a predetermined low speed so that the flow velocity in the upper and lower parts becomes the circumferential velocity towards the storage tank 5 or 65'. In a circulation process outside the tank body, it is heated to a predetermined temperature by a heater 8, and at the same time, a filter 7 completely removes dust and other submicron particles.

The internal number of the tank body is a holder that immerses the workpieces 1 (in Fig. 1, a predetermined number of them are arranged in parallel from the front side to the back side) into the pure water 2, taking over from the previous stage precision cleaning. 1
The workpiece 1 can be freely immersed and pulled up by a suitable lifting device 12, and a dry gas 3 such as air is contained in the water 13 above the water surface of the pure water 2. On the other hand, a circulation fan 14 having a built-in Nabumicron trapping filter that circulates the inside of the DiX-shiba 13 at a predetermined low speed and a heater 15 that heats the dry gas 3 to a predetermined temperature are provided at a predetermined position and orientation.

Further, infrared lamps 16, 16 for emitting heat rays are installed at both sides of the elevated position level of the workpiece 1.

The workpiece 1 manufactured in the previous stage and precisely cleaned in a predetermined number of stages using a predetermined cleaning liquid or ultrasonic waves is cleaned with pure water [for the final cleaning in 4, the circulation pump 6, filter 7, and heater 8 are The pure water 2, which has been heated to a predetermined temperature after removing dust on the order of microns, is passed through the circulation circuit 9 from the storage tank 5 side to the 5' side via perforated plates 10, 10, etc., so that the speed of the upper and lower parts is the same. The dry gas 13 in the upper part is caused to flow laterally in a laminar flow state, and the air 3 in the upper dry gas is brought into the diton bar 13 at a predetermined level by a circulation fan 14 and a heater 15. It captures and removes medium-sized submicron dust at low speed and circulates it.

Then, the infrared lamps 16 and 16 are turned on to emit hot infrared rays to heat the 1"L dry gas 13 and raise its temperature.

This position is located at the elevated level of the workpiece 1.

Then, the object to be cleaned 1 that has been baton-touched from the previous precision cleaning by the holder 11 is immersed in the pure water 2 in the pure water cleaning tank 4, and after a predetermined time has elapsed, it is heated as close to zero as possible via the lifting device 12. It is pulled up vertically from the surface of pure water 2 into dry gas 3 at extremely low speed.

In the lifting process, the purified water 2 adheres to the cleaning surface of the object 1 to be cleaned in a thin film form by a predetermined height h according to the above-mentioned principle, but does not rise above the top of the height. When the drying gas 3 comes into contact with the drying gas 3, the drying action is instantaneous compared to the ultra-low rising speed, and since it is performed on the thin film of pure water 2, as mentioned above, spot blocking occurs. No water droplet-like concentration phenomenon occurs, and
The drying gas 3 is heated and heated by the infrared rays of heat rays emitted from the infrared lamp 16.16, and the workpiece 1 is also heated and heated, so drying is accelerated, and therefore, stains etc. do not occur on the cleaning surface. In addition, the blowing of the drying gas 3 does not cause any disturbance due to etc., and ultra-precise drying is performed as designed.

By repeating the drying operation as described above, highly accurate drying can be achieved.

As mentioned above, while the object 1 to be cleaned is being raised and lowered relative to the pure water 2, by creating a laminar lateral flow with respect to the pure water 2 in the supplementary water cleaning tank 4, a layer with exactly the same speed in the vertical direction is created. The drying gas 3 is also circulated so that the circulation fan 14 forms a laminar flow toward the upper side by the circulation fan 14, and the drying gas 3 is circulated. It is also possible to filter and remove dust that is filtered by the filter in the fan 14 and turned into submicron particles.

It goes without saying that the embodiments of the invention of this application are not limited to the above-mentioned embodiments; for example, various embodiments can be adopted, such as being applicable to the precision cleaning process using a chemical solution in the first stage. .

Effects of the Defense> As described above, according to the invention of this application, a deionized water cleaning tank using deionized water in 33 steps is used for finishing cleaning, which is one variation of precision cleaning in the finishing process of ultra-precision parts such as electronic parts and optical parts. After cleaning by immersing the workpiece in pure water, in the process of lifting the workpiece from the pure water, the speed at which the pure water is pulled up is set to an extremely low speed so that the surface of the workpiece to be cleaned is covered with pure water. Due to the balance between the cohesive force and surface tension of pure water, the thin film of water adheres to a certain height and rises, and does not rise any further. Pure water in the form of water droplets does not adhere,
In addition, since the workpiece and the drying gas around it are heated and heated with heat rays such as infrared rays and near-infrared rays, the drying speed is accelerated and instantaneous drying is performed as quickly as possible. There is no condensation of sub-micron dust or cleaning liquid used in the previous process, so there is no staining, and the cleaning surface is extremely clean during cleaning and drying.
The excellent effect of being defeated is Qin.

In addition, since the pure water for finishing cleaning is circulated laterally in the cleaning tank as a laminar flow, dust and other particles that accidentally enter the cleaning tank do not accumulate and are reliably captured by filtration during the circulation process. It has the effect of being removed.

In addition, since the upper drying gas is also subjected to precision filtration treatment, even during the drying process of the cleaning surface of the object to be cleaned, which is pulled up from pure water at an ultra-low speed, dust in the order of 100 microns can be accidentally mixed in. It also has the excellent effect of not adding stones.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention, FIG. 2 is a side view of the same, and FIG. 3 is a sectional view of the basic embodiment. 2...Pure water, 1...Object to be cleaned, 17...Heat ray J 2--1 Purity 1-11 Decontaminated object 17--Kyo repeat

Claims (2)

[Claims] (1) In a drying method in which moisture is removed from the surface of the object to be cleaned in a dry gas after final cleaning with pure water following the preliminary precision cleaning of the object, the object to be cleaned is immersed in the above-mentioned purified water. A drying method for precision cleaning, characterized in that an object is pulled up from the water surface into the drying gas at an extremely low speed, and then heat rays are radiated onto the object to be cleaned in the drying gas. (2) The precision cleaning drying method according to claim 1, wherein the heat ray is an infrared ray.