KR20060080902A - Organic contaminants removal in fine pattern using hypercritical mixing fluid - Google Patents

Abstract

The present invention relates to a method for cleaning a microcircuit, and more particularly, when carbon dioxide is above a certain temperature and a certain atmospheric pressure, it becomes a supercritical fluid state having an intermediate property of a liquid and a gas, and further pressurizes to make an ultrahigh pressure state to increase density. It is a technology that cleans microcircuits by making a mixed fluid by mixing a very small amount of organic solvent and ultrapure water (3rd DW) to further increase cleaning power. In addition, semi-automated cleaning is possible through the continuous arrangement of the fluid pump, and the cleaning of the microcircuits includes an eco-friendly recovery / filtration process that recovers the carbon dioxide, the organic solvent, and the DW used in the cleaning process, and filters and reuses it. Is done. Through this, we developed a method that enables the implementation of microcircuits of printed circuit boards (PCB, Rigid PCB, Flexible PCB, Optical PCB), dramatically improves existing environmental pollution processes, and realizes products that utilize the characteristics of materials.

CO2, DW, Organic Solvent, Microcircuit, Recovery / Reuse, Printed Circuit Board

Description

Organic Contaminants Removal in fine pattern using hypercritical mixing Fluid

1 is a block diagram for explaining the equipment implementation of the ultra-high pressure fluid according to the present invention,

2 is a flowchart illustrating a clean microcircuit cleaning process using an ultrahigh pressure fluid according to the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to cleaning substrates during a microcircuit manufacturing process, and more particularly, to a method for cleaning a microcircuit substrate using ultra high pressure carbon dioxide.

A brief summary of the microcircuit fabrication process is divided into oxidation process, diffusion process, pattern process, etching and pattern deposition process. Each of these processes must go through a cleaning process to remove contaminants from the substrate surface. Chemicals widely used in microcircuit cleaning include ammonia and sulfuric acid, and megasonic is used as a physical method.

  The conventional microcircuit cleaning process is largely divided into a UV process for firstly removing particles and metal impurities using a chemical, and a second process using a DIW to remove residual chemicals, and a third process for removing organic materials.

However, the cost of each process is enormous. In particular, in the case of a flexible printed circuit board using a low temperature optical waveguide material, since the semiconductor level is required to be cleaned, the development of an improved cleaning technology is urgently needed.

  Also, in the actual process, the radicals generated in each process on the microcircuit interfere with the physical and chemical bonds between the thin films and reduce the production yield. The chemical and physical cleaning used to remove this creates crystallographic bonds and residual ions in the thin film, which degrades the performance and causes another production yield reduction. Therefore, it is required to introduce a microcircuit cleaning apparatus using ultra high pressure, which is a new cleaning method that is environmentally friendly and does not generate ions.

  Recently, due to the demand for environmental protection and low manufacturing costs, the reduction of chemical consumption is becoming an important issue. As the environment changes, the development of an eco-friendly process that maintains the ability to remove contaminants in the conventional liquid cleaning process and does not generate any waste water at all will be an important technology in the future. Therefore, several physical cleanings (Ultrasonic cleaning), wet cleaning and dry cleaning have been proposed since 1990, aiming to add new functions and lower the cost of the cleaning process.

  In the wet cleaning method, the cleaning function is gradually being improved. However, due to the problem that a very large amount of ultrapure water is used in the entire production process of the microcircuit board, the cleaning function, the running cost of the cleaning process, Problems such as wastewater treatment remain. In addition, the surface treatment of the microcircuit currently used has a large number of chemicals are used in large quantities, which always includes problems such as the cost of chemicals, post-treatment costs, worker safety, environmental pollution.

  That is, since a large amount of wastewater and wastes are generated due to a large number of chemicals and a large amount of water used in the cleaning process, problems such as cost increase, worker safety problems, and pollution generation occur. Therefore contaminants rather than treatment

There is a strong demand for the development of a new process that does not generate pollutants from the standpoint of not generating any at all.

An object of the present invention is to provide an environment-friendly cleaning method using almost no ultrapure water by reusing the mixed gas used after cleaning can be recycled with little use of chemicals.

  It is still another object of the present invention to provide a cleaning method having high economical efficiency by reducing the cleaning cost by using environmentally friendly ultrahigh pressure mixed fluid and reducing the cost due to the simplification of the process.

The present invention relates to a method for cleaning a microcircuit, and more particularly, to a method for cleaning a microcircuit with ultra high pressure carbon dioxide, a very small amount of an organic solvent and ultrapure water.

 The microcircuit cleaning method according to the present invention includes an ultrahigh pressure fluid generating process for generating an ultrahigh pressure fluid using an ultrahigh pressure fluid generating device; A stirring step of mixing and stirring the ultrahigh pressure fluid, the organic solvent and the ultrapure water to generate an ultrahigh pressure mixed fluid; Activation process through the nozzle; A cleaning process for cleaning the microcircuit using the activated ultrahigh pressure mixed fluid; And a recovery / reuse process for recovering the ultra-high pressure mixed fluid used in the cleaning process, filtration, and reuse. It is made, including.

 Hereinafter, the present invention will be described in detail for each process with reference to the drawings.

 1 is a block diagram illustrating an ultrahigh pressure mixed fluid generating device and cleaning according to the present invention, and FIG. 2 is a flow chart illustrating microcircuit cleaning using the ultrahigh pressure mixed fluid according to the present invention.

 Ultra High Pressure Carbon Dioxide Fluid Production Process (F100)

It becomes a supercritical fluid having intermediate properties between liquid and gas at a constant temperature (31 degrees) and a constant pressure (73 atmospheres). In this state, the pressure is further increased to increase the density, thereby making the ultrahigh pressure fluid. In addition, by using multiple pumps, pressure loss can be minimized, which can entail a drastic improvement in processing capacity.

 Mix / Activation Process (F200)

This step is a step of mixing the ultra-high pressure fluid generator, the carbon dioxide supplying device, the organic solvent and ultrapure water using a stirring device.

That is, in the mixing zone of the ultra-high pressure fluid generator, the ultra-high pressure carbon dioxide, organic solvent, and ultrapure water generated in advance are mixed and the mixed fluid is stirred using a stirring device to generate the ultra-high pressure mixed fluid.

 Cleaning process (S400)

In this step, the ultra-high pressure mixed fluid is sprayed onto a microcircuit requiring cleaning to clean contaminants present on the microcircuit.

In other words, the ultra-high pressure mixed fluid is sprayed onto the surface of the microcircuit using an injector to clean contaminants.

Ultra-high pressure mixed fluids replace chemicals in the particle and metal impurities removal process. In addition, the mixed fluid of the polar organic solvent and the non-polar ultrapure water is adsorbed on the surface of the substrate during the cleaning process and serves to remove organic substances that impair the performance of the microcircuit.

 Recovery / filtration / reuse process (S500)

This process is to recover and filter the ultra-high pressure mixed fluid used for cleaning the substrate in the cleaning process, and to reuse it in the ultra-high pressure mixed fluid production process.

The recovered ultra-high pressure mixed fluid contains contaminants and various foreign substances generated during the cleaning process and cannot be reused as they are.

Therefore, the recovered ultra-high pressure mixed fluid is to be separated and filtered and then used again using a separation and filtration device. When the filtration apparatus lowers the pressure of the ultrahigh pressure fluid, the fluid having a medium property of liquid and gas becomes a gaseous state, and its dissolving power is very low. At this time, the phase separation occurs naturally and is separated into a very small amount of organic solvent, ultrapure water and carbon dioxide. The filtration process uses a filter that can remove fine particles and a filtration device that also performs deionization to remove ions. However, even if not reused in the case of the present invention does not generate salt even when mixing the waste water (acidic water and alkaline water) generated after washing, since it becomes neutral water during mixing, natural drainage is possible without additional treatment. The present invention is therefore a very environmentally friendly technique.

Through the present invention, it will be possible to clean the micropattern gradually decreasing in size up to several nanometers, and will result in drastic reductions or non-generation of wastewater and waste liquid from the current cleaning method. On the other hand, the operating cost can be reduced by recycling the used solvent.

Claims (7)

Converting carbon dioxide into a supercritical fluid state and then mixing and mixing an organic solvent and ultrapure water, and then pressurizing to produce an ultrahigh pressure mixed fluid; A cleaning process for cleaning the microcircuit board by using the ultrahigh pressure mixed fluid; A mixed fluid separation and recovery / filtration step after the washing step; Cleaning process technology for microcircuits characterized in that The method of claim 1, wherein the ultra-high pressure mixed fluid refers to a mixed fluid in which carbon dioxide, ultrapure water and an organic solvent form the same phase. The ultra-high pressure mixed fluid is adsorbed on the surface of the microcircuit to remove the organic substances that hinder the performance of the substrate, the cleaning process of the microcircuit using the ultra-high pressure mixed fluid, characterized in that to replace the organic solvent Cleaning the Rigid PCB Using the Ultra High Pressure Fluid Cleaning of Flexible PCB Using the Ultra High Pressure Mixed Fluids Cleaning of Optical Rigid PCB Using the Ultra High Pressure Mixed Fluid -1 Cleaning of Impurity Walls Formed in the Optical Waveguides in the Photosensitive Circuit Board of FIG. -2 Cleaning of impurities generated during the replication process (embossing process) in the photocurable circuit board of FIG. Cleaning of the Optical Flexible PCB Using the Ultra High Pressure Mixed Fluid -1 Cleaning of Impurity Walls Formed in the Optical Waveguide of the Flexible Circuit Board of FIG. -2 Cleaning of impurities generated during the copying process (embossing process) in the flexible circuit board of FIG.

Images