KR20090100070A - System for cleaning semiconductor device - Google Patents

Abstract

PURPOSE: A system for cleaning a semiconductor device is provided to reduce a processing time by configuring a chamber for a wafer cleaning process. CONSTITUTION: In a system for cleaning a semiconductor device, a photo process apparatus(200) includes a scanner(240), a coater(230), an evaporator(220), and a cleaner(260). The scanner projects beam to a wafer and forms a certain pattern, and the coater coats a wafer. The evaporator deposits the material injected into a wafer, and the cleaner unifies the scanner, the coater, and the evaporator into one track. The cleaner washes the foreign material on the wafer by using air bubbles.

Description

Semiconductor Cleaning System {SYSTEM FOR CLEANING SEMICONDUCTOR DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor cleaning system. In particular, various particles remain on the front and rear surfaces of a wafer due to etching and peeling during the process of manufacturing a semiconductor device, thereby reducing defects in the manufacturing process. It is a technique related to the washing apparatus for.

The semiconductor device may be operated according to a predetermined purpose by injecting impurities into a predetermined region of a silicon wafer or depositing a new material. Manufacturing equipment for manufacturing such a semiconductor device is commonly referred to as semiconductor equipment, and can be divided into equipment that enters the preprocessing line, equipment that enters the postprocessing line, and service equipment.

The process of manufacturing a semiconductor device is very complicated and divided into various stages. For example, a representative example of a semiconductor device is a semiconductor memory device in which an ion implantation process injects impurities into a portion of a silicon wafer, a process of depositing a material such as an oxide film or a nitride film in a portion of a region, or a material that has already been deposited. Etching processes such as chipping or chipping silicon wafers and chemical mechanical polishing to planarize the deposited material must be performed. In addition, it is possible to manufacture a highly integrated semiconductor memory device in a small area only if each step is performed exactly at a designated point on the silicon wafer. However, most of the processes performed on silicon wafers cause contaminants on the front or back of the silicon wafer, requiring more effort to remove them.

When contaminants are generated on a silicon wafer, the contaminants are very difficult to accurately perform in a predetermined position at various stages to be performed later. An example is defocus. Poor focus refers to a case in which the contamination on the silicon wafer causes misalignment between the equipment and the wafer, or the bending causes the contamination. To prevent this phenomenon, a cleaning process must be performed to remove contaminant particles generated on the wafer after various processes.

As mentioned above, processes on the wafer produce contaminants, and cleaning processes, whether to ensure the performance of the semiconductor device without defects or to improve the yield in manufacturing the semiconductor device, are to completely remove the contaminants on the wafer. It is a goal. However, since it is impossible to completely remove the contaminants through the cleaning process, the main purpose is to minimize the amount of contaminants before and after the cleaning process by removing the contaminants as much as possible. For reference, the apparatus for such a cleaning process is included in both the equipment entering the above-mentioned preprocessing line, the equipment entering the post-processing line, and the service equipment.

The contaminants generated on the silicon wafer in the process of manufacturing the semiconductor device can be largely divided into particles (particles), organic contaminants, metal contaminants, natural oxide film and the like. Because of the variety of contaminants, there may be a variety of cleaning methods to remove them. However, since the time required for the manufacturing process of the semiconductor device is also very important, various cleaning solutions are mixed and cleaned in a batch to effectively remove various kinds of contaminants.

Currently, the wet cleaning process used in the semiconductor process is based on the RCA substrate cleaning process published by Kern and Puotinen in the 1970s without any significant change in the composition of the chemical solution. RCA cleaning involves SC1 (Standard Clean-1, Ammonia peroxide mixture, APM) process using mainly ammonia basic solution and SC2 (Standard Clean-2, Hydrochloric acid and peroxide mixture (HPM) process using mainly acidic solution, hydrochloric acid. There are two major ways to use. More specifically, the SC1 process is commonly used to remove particles and organic contaminants at a temperature of 75-90 ° C. by mixing ammonia, hydrogen peroxide, and water in a ratio of 1: 1: 5. This causes the etching of the wafer surface by ammonia and the oxidation reaction of the wafer surface by hydrogen peroxide simultaneously to effectively remove the particles on the wafer surface. However, the cleaning solution used in the SC1 process could not avoid metal contamination on the surface due to the low redox potential, and the SC2 process appeared to remove it. The SC2 process is used to remove transitional metal contaminants by mixing hydrochloric acid, hydrogen peroxide, and water in a ratio of 1: 1: 5. This effectively removes metal contaminants electrically coupled to the wafer surface by electrochemical reactions with hydrogen peroxide and hydrochloric acid.

In addition, the wet cleaning process includes a SPM (Surfuric acid peroxide mixture) process using a solution of sulfuric acid and hydrogen peroxide in a 4: 1 ratio that is effective for removing organic contaminants or large particles on the silicon wafer surface, and a natural oxide film on the silicon wafer surface. However, there is a diluted HF (DHF) process that uses a solution of 10- or 100-fold dilution of hydrofluoric acid (HF) with DI water.

The above-described wet cleaning process, which applied the chemical in the liquid state, had the convenience of the process or the low cost effect, but it was difficult to integrate the process and difficult to clean the minute circuit due to the reduction of design rules. As a result, in recent years, although the technology is difficult to implement, dry cleaning equipment has been developed to enable the cleaning of fine circuits using plasma gas. Specifically, dry cleaning functions to wash off the oxide film remaining on the wafer in the intermediate stage of the etching process of cutting out unnecessary parts of the circuit in the entire semiconductor process and the ashing process of removing the photoresist (PR). Equipment was developed. However, dry cleaning equipment is still not used to remove various kinds of contaminants and efforts are being made to remove contaminants that are difficult to remove only by conventional wet cleaning processes.

In order to solve the above-mentioned conventional problems, the present invention prevents poor focusing in the subsequent manufacturing process by contaminants on the front and rear of the silicon wafer by cleaning the silicon wafer by generating air bubbles using an ultrasonic oscillator in the wet cleaning process. It provides a cleaning equipment for.

The present invention is unified in one track, a scanner for making light into a wafer to form a shape, a coater for coating a wafer, a vapor deposition machine for depositing a substance injected into the wafer, and a scanner, a coater, and a vapor deposition machine. It provides a photo process semiconductor equipment including a scrubber for cleaning the foreign matter on the wafer transferred to the air bubbles.

Preferably, the cleaner includes a chamber for immersing the wafer in the cleaning liquid, a nozzle for injecting gas for bubble generation into the chamber, an ultrasonic generator for scanning ultrasonic waves into the chamber, and a reflector for reflecting the ultrasonic waves to the outside.

Preferably, the ultrasonic generator is characterized by scanning the ultrasonic wave of 400MHz for 20 seconds. In addition, the ultrasonic generator is mounted on one side of the chamber, the reflector is characterized in that it is included in the chamber opposite the ultrasonic generator.

Preferably, the cleaning liquid used in the chamber is water (H ₂ O), in particular pure water (DI water) is used. In addition, the gas injected into the chamber is characterized in that the nitrogen (N2).

Preferably, the photoprocess semiconductor device further includes a plate for heating or cooling the wafer.

The present invention also provides an air bubble including a chamber for immersing a wafer in water, a nozzle for injecting nitrogen gas for bubble generation into the chamber, an ultrasonic generator for scanning ultrasonic waves in the chamber, and a reflector for reflecting the ultrasonic waves to the outside. Provide a scrubber.

Preferably, the ultrasonic generator is characterized in that for 20 seconds to scan 400MHz ultrasonic wave is mounted on one side of the chamber, the reflector is characterized in that it is contained in the chamber opposite the ultrasonic generator.

The present invention can effectively control the foreign matter on the front and rear of the wafer, so that the defect caused by the foreign matter in the coating process after the cleaning process, the defect caused by the poor focus caused by the foreign matter in the scanning process, and the foreign matter due to the foreign matter There is an advantage that can prevent the phenomenon such as contamination.

In addition, the present invention, unlike the conventional cleaning equipment can simplify the configuration of the chamber (chamber) for the wafer cleaning process has the advantage that it can be included in the equipment for performing the photo process to reduce the process time.

Hereinafter, with reference to the accompanying drawings will be described in detail an embodiment of the present invention.

1 is a perspective view illustrating a cleaning apparatus for performing a cleaning process according to an embodiment of the present invention. In particular, the cleaning apparatus of the present invention effectively removes foreign matter remaining on the front and rear surfaces of the wafer when the wafer is transferred to the photo process through various processes, thereby causing defects due to coating defects on the wafer or poor focus in subsequent scanning processes. It is to prevent this from happening.

As shown, the scrubber according to an embodiment of the present invention, the chamber 100 for immersing the wafer in the cleaning liquid, the nozzle 160 for injecting the gas for generating bubbles into the chamber, the ultrasonic in the chamber 100 Ultrasonic generator 140 for scanning the, and a reflecting plate 120 for reflecting the ultrasonic wave to the outside.

The cleaning liquid contained in the chamber 100 uses water (H ₂ O), and particularly preferably pure water (DI water). In addition, nitrogen (N 2) is used as a gas for bubble generation. In the present invention, since an additional chemical reaction is generated by a cleaning liquid or a gas to remove foreign substances remaining on the wafer by generating vortices caused by ultrasonic waves and injecting air bubbles, the wafer may be damaged by nitrogen (N _2). ) And stable water (H ₂ O).

In addition, the ultrasonic generator 140 scans ultrasonic waves having a frequency of about 400 MHz for about 20 seconds to generate vortices with vibrations in the chamber 100. The vortices generated in this way can remove foreign substances remaining on the front and rear surfaces of the wafer. The ultrasonic generator 140 is mounted on one side (side) of the chamber 140, and the reflector plate 120 is included in the chamber 140 positioned opposite to the side on which the ultrasonic generator 140 is mounted. The reflective plate 120 reflects the ultrasonic waves scanned by the ultrasonic generator 140 when they reach the opposite side of the chamber through the plurality of wafers contained in the chamber 100 and send them to the outside.

Hereinafter, the process of cleaning the wafer in the chamber 100 will be described in detail. The chamber 100 contains a plurality of wafers to be cleaned and water (H ₂ O), which is a cleaning liquid, and nitrogen (N ₂ ) is injected to generate air bubbles. With the injection of nitrogen (N ₂ ), the ultrasonic generator 140 scans the ultrasonic waves into the chamber 100 to explode bubbles around the wafer. Vortex in the chamber 100 is generated due to the energy generated by the bubbles burst along with the vibration due to the ultrasonic waves, and the vortices can wash away the particles remaining on the front and rear surfaces of the wafer. Ultrasonic waves scanned by the ultrasonic generator 140 and blown off by air bubbles around the wafer are reflected by the reflector 120 and removed out of the chamber 100.

FIG. 2 is a conceptual diagram for describing a photoprocessing apparatus 200 including the cleaning apparatus illustrated in FIG. 1.

As shown, the photoprocessing equipment 200 includes a cleaning device 260 using air bubbles on an internal track. The photo process equipment 200 includes a scanner 240 for shooting light onto a wafer to form a shape, a coater 230 for coating a wafer, a deposition machine 220 for depositing a material injected into a wafer, and a scanner 240. ), The coating machine 230, and the deposition unit 220 and the unitary track, and includes a cleaning device 260 for cleaning the foreign matter on the wafer to be delivered to each of the air bubbles. In addition, the photoprocess semiconductor device may further include a plate 210 for heating or cooling the wafer.

In the conventional case, the apparatus for cleaning the wafer is composed of several stages, and each stage requires several accessory apparatuses for processing the necessary cleaning liquid and waste generated after cleaning, so that the total volume of the equipment for the cleaning process is quite large and complicated. It was difficult to include in the photo process equipment 200 for performing the photo process. However, the cleaning device 260 according to an embodiment of the present invention can be simply configured through the chamber 100, the ultrasonic generator 140, and the nozzle 160 for cleaning, so that the photoprocessing equipment 200 may be It's easy to configure one line with the other devices included.

Defects occur when the coating process or the scanning process is performed while leaving a lot of foreign matter on the front and rear surfaces of the wafer transferred to the photo processing apparatus 200 through various processes. As shown in FIG. 2, the cleaning device using air bubbles 260 removes foreign substances by injecting ultrasonic waves before an initial step of HMDS (Hexa Methyl Di Silazane, Si ₂ (CH ₃ ) ₆ ) to coat the wafer. An example is shown. Here, the HMDS step is performed to change the surface of the wafer to hydrophobicity. Photoresist is mainly used in the photo process (Photoresist) is mainly composed of an organic solvent, to improve the adhesion of the photoresist on the wafer by performing the HMDS step on the wafer that can be easily hydrophilic.

The cleaning device 260 removes foreign matter remaining on the front and back sides of the wafer from the track in the photo processing apparatus 200 immediately before performing the coating process, thereby preventing coating defects and focus defects in the scanning equipment. And a single track with devices for performing different processes, greatly reducing the time for cleaning.

In addition, a preferred embodiment of the present invention is for the purpose of illustration, those skilled in the art will be able to various modifications, changes, substitutions and additions through the spirit and scope of the appended claims, such modifications and changes are the following claims It should be seen as belonging to a range.

1 is a perspective view for explaining a cleaning apparatus for performing a cleaning process according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram for describing a photoprocessing apparatus including the cleaning device illustrated in FIG. 1.

Claims (11)

A scanner for shooting light onto a wafer to form a shape; A coater for coating the wafer; An evaporator for depositing material injected into the wafer; And The scanner, the coater, and the evaporator are united in one track, and a cleaner for cleaning foreign substances on the wafers transferred to each other using air bubbles. Photo process semiconductor equipment comprising a. The method of claim 1, The scrubber A chamber for dipping the wafer in a cleaning liquid; A nozzle for injecting gas for bubble generation into the chamber; An ultrasonic generator for injecting ultrasonic waves into the chamber; And Photo process semiconductor equipment comprising a reflector for reflecting the ultrasonic wave to the outside. The method of claim 2, The ultrasonic generator is a photo process semiconductor equipment, characterized in that for 20 seconds to scan the ultrasonic wave of 400MHz. The method of claim 2, And the ultrasonic generator is mounted on one side of the chamber, and the reflector is included in the chamber opposite to the ultrasonic generator. The method of claim 2, The cleaning liquid is water (H ₂ O) Photo process semiconductor equipment, characterized in that. The method of claim 5, And the water is pure water (DI water). The method of claim 2, The gas is a photo process semiconductor equipment, characterized in that the nitrogen (N2). The method of claim 1, The photo process semiconductor device further comprises a plate for heating or cooling the wafer. A chamber for immersing the wafer in water; A nozzle for injecting nitrogen gas for bubble generation into the chamber; An ultrasonic generator for injecting ultrasonic waves into the chamber; And Reflector for reflecting the ultrasonic wave to the outside Air bubble cleaner comprising a. The method of claim 9, And the ultrasonic generator scans 400 MHz ultrasonic waves for 20 seconds. The method of claim 9, And the ultrasonic generator is mounted on one side of the chamber, and the reflector is included in the chamber opposite to the ultrasonic generator.

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