KR19980030939A - Wafer cleaning method - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

Wafer cleaning method.

2. The technical problem to be solved by the invention

It is intended to provide a wafer cleaning method that can effectively remove organic matter, which is an impurity that remains on the wafer surface and can affect device formation.

3. Summary of Solution to Invention

CLAIMS 1. A cleaning method for removing an organic material on a surface of a wafer on which a silicon film implanted with an impurity ion or an ion implantation is formed, the method comprising: growing an oxide film on the silicon film by cleaning the wafer with hydrogen peroxide; And removing an organic material on the wafer by using a mixed solution of sulfuric acid and hydrogen peroxide solution.

4. Important uses of the invention

Used in wafer cleaning process in semiconductor device manufacturing process.

Description

Wafer cleaning method

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of cleaning a wafer in a semiconductor device manufacturing process, and more particularly to a method of cleaning a wafer using sulfuric acid, which is effective for removing organic matter remaining on a wafer.

In general, the wafer after each unit process is cleaned on the surface of the wafer to remove particles or contaminants that may affect the formation of the device and remain on the surface of the wafer. Particles and contaminants that may affect the formation include, firstly, organic matter such as carbon and its series of photoresist residues and surfactant components in the developer, and wiring breakage, which cause crystal defects, pinholes, and poor contact conduction. Minerals from particles of oxides, nitrides, and other equipment that cause pattern defects such as increased resistance; and third, metal impurities such as aluminum, sodium, and copper, which cause problems such as reducing joint leakage and lifetime. An oxide film, that is, spontaneously grown in air and water, which causes poor current conduction and deterioration of film properties. Oxide and the like (Native Oxide).

1 is a conceptual diagram illustrating the prior art and its problems, and is a cleaning process for effectively removing organic substances such as carbon and photoresist residues thereof, and surfactant components in a developer, which cause crystal defects, pinholes, and poor contact conduction. It is about process.

First, the polycrystalline or single crystal silicon film 2 formed on the silicon substrate 1 is deposited, and then impurities (for use as a conductive film) are deposited. Doping), applying a photoresist on the silicon film 2, patterning the photoresist by a series of lithography processes, and then etching the photoresist pattern as an etch barrier. Photoresist residue used as the etch and ion implantation mask while undergoing several unit processes such as patterning a photoresist or implanting impurity ions onto the silicon film 2 of a predetermined portion using a photoresist as an ion implantation mask. And organic substances such as surfactant components in the developer.

Thus, sulfuric acid at about 130 ° C. may be used to prevent the organics from causing crystal defects, pinholes, and poor contact conduction in subsequent processes. ) And hydrogen peroxide ( The wafer was cleaned using a chemical solution mixed with 3: 1.

However, at this time, sulfuric acid (a cleaning solution) ) And phosphorus doped or ion implanted into the silicon film 2 Reacts to form phosphorus in the silicon film 2 ) Is outdiffused to form phosphorus in the silicon film 2. There was a problem such that the concentration of h) decreases.

Disclosure of Invention The present invention devised to solve the above problems is to provide a wafer cleaning method capable of effectively removing organic matter, which is an impurity that may remain on the wafer surface and affect device formation.

1 is a cross-sectional view of a wafer cleaning process in the prior art;

Figure 2 is a cross-sectional view of the wafer cleaning process according to an embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

10 silicon substrate 20 silicon film

30: oxide film

In order to achieve the above object, the present invention provides a cleaning method for removing an organic material on the surface of a wafer on which a silicon film is doped or implanted with impurity ions, wherein the wafer is cleaned using hydrogen peroxide solution to form an oxide film on the silicon film. Growing; And removing the organic material on the wafer using a mixed solution of sulfuric acid and hydrogen peroxide solution.

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

2 is a cross-sectional view of a wafer cleaning process according to an embodiment of the present invention, after depositing a polycrystalline or single crystal silicon film 2 formed on a silicon substrate 10, and then using an impurity (eg, a conductive film) for use as a conductive film. Doping), applying a photoresist on the silicon film 20, patterning the photoresist by a series of lithography process, and then using the photoresist pattern as an etch barrier the silicon film 20 Photoresist residue used as the etch and ion implantation mask while undergoing several unit processes such as patterning a process or implanting impurity ions onto the silicon film 20 at a predetermined portion using a photoresist as an ion implantation mask. And about 30 wafers contaminated with organics such as surfactant component in developer at room temperature before cleaning process with sulfuric acid. Hydrogen peroxide with a concentration of The wafer is cleaned by using a C, and the oxide film 30 is grown on the silicon film 20, and then sulfuric acid of about 130 ° C. ) And hydrogen peroxide ( ) Shows the cleaning of the wafer using a chemical solution mixed with 3: 1.

Thereafter, after the oxide film generated by the hydrogen peroxide solution is removed, a washing process using pure water (DI Water) is performed.

The present invention described above is not limited to the above-described embodiment and the accompanying drawings, and various substitutions, modifications, and changes are possible in the art without departing from the technical spirit of the present invention. It will be evident to those who have knowledge of.

In the present invention as described above, the oxide film is grown on the entire surface of the wafer by performing a cleaning process with hydrogen peroxide prior to the sulfuric acid cleaning process for removing organic substances, which are contaminants that may remain on the surface of the wafer and affect device formation. Next, the phosphorus doped or ion implanted into the silicon film Is sulfuric acid React with phosphorus in the silicon film ) Is outdiffusion and the phosphorus in the silicon film ) Can be prevented from lowering, thereby improving the wafer surface concentration stabilization and cleaning effect.

Claims (3)

In the cleaning method for removing the organic material on the surface of the wafer on which a silicon film implanted with an impurity ion or ion implanted is formed, Cleaning the wafer with hydrogen peroxide solution to grow an oxide film on the silicon film; And And removing the organic matter on the wafer by using a mixed solution of sulfuric acid and hydrogen peroxide water. The method of claim 1, The cleaning process using the hydrogen peroxide water is a wafer cleaning method, characterized in that proceeds at room temperature. The method of claim 2, The concentration of the hydrogen peroxide used in the washing process using the hydrogen peroxide water is about 30 Wafer cleaning method characterized by the above-mentioned.