KR19990043548A - High Temperature Oxide Film Deposition Method on Tungsten Silicide Film - Google Patents

Abstract

The present invention relates to a high temperature oxide film deposition method on a tungsten silicide film.

The present invention includes the steps of depositing a tungsten silicide film on a wafer, after the deposition of the tungsten silicide film, arranging the wafers horizontally and heat treating, cleaning the heat-treated wafers and arranging the cleaned wafers horizontally. It comprises a step of depositing a high temperature oxide (HTO: High Temperature Oxide).

Therefore, when the high temperature oxide film is formed on the tungsten silicide film, the arrangement and cleaning conditions of the wafer are modified to prevent particles from being generated by the tungsten oxide formed on the tungsten silicide film, thereby forming a homogeneous high temperature oxide film.

Description

High Temperature Oxide Film Deposition Method on Tungsten Silicide Film

The present invention relates to a high temperature oxide (HTO) deposition method on a tungsten silicide (W-Silicide) film.

As the degree of integration of semiconductors increases, polycrystalline silicon is approaching its limit as an interconnect material for connecting devices. The polysilicon has high contact resistance and surface resistance, and thus high speed cannot be obtained. Therefore, a silicide film, which is a compound of metal and silicon, is used instead of the polycrystalline silicon.

As the silicide film deposition method, evaporation, sputtering, and chemical vapor deposition (CVD) are used. Currently, the best chemical vapor deposition method is used the most in terms of reproducibility and uniformity.

Tungsten silicide (W-Silicide) film, which is one of the silicides, is used in various processes. In addition, other films may be deposited on the tungsten silicide film. One of them is a high temperature oxide film.

1 is a process flowchart showing a method for depositing a high temperature oxide film on a tungsten silicide film according to a conventional method.

As shown in FIG. 1, a tungsten silicide film is deposited on a semiconductor substrate by chemical vapor deposition. Next, in the heat treatment step of the deposited tungsten silicide film, the uniformity of the tungsten silicide film is improved and the resistance is minimized. Next, the cleaning step removes contaminants and particles on the tungsten silicide layer so as not to adversely affect the next process. Next, a high temperature oxide film is deposited on the tungsten silicide film after the cleaning step.

The process of depositing a high temperature oxide film on the conventional tungsten silicide film has the following problems.

When the tungsten silicide film is deposited, tungsten oxide and silicon oxide are inevitably generated during the deposition process. The presence ratio of the tungsten oxide and the silicon oxide may be present in a large amount of the tungsten oxide or vice versa depending on the process conditions and conditions.

FIG. 2 is a schematic configuration diagram of a chamber showing a wafer arrangement state during heat treatment and deposition in a high temperature oxide film deposition method on a tungsten silicide film according to a conventional method.

The tungsten oxide is volatile and out gassed by high heat during the heat treatment and high temperature oxide film deposition. As shown in FIG. 2, the wafer 14 has a bottom surface 12 in the process chamber 10. The outgassed tungsten oxide is recombined to form particles on the tungsten silicide layer when the heat treatment and the high temperature oxide film process are arranged vertically with respect to each other. In this case, the tungsten oxide grows in the form of large particles, and these particles grow as impurities and cause problems in various processes.

In the cleaning process, the tungsten silicide film reacts with hydrogen fluoride to form the silicon oxide by the tungsten oxide and the surplus silicon, and the depth of penetration into the tungsten silicide film increases as the cleaning time by the hydrogen fluoride increases. Thus, the thick silicon oxide film and the tungsten oxide film are formed.

The thickness of the silicon oxide and powdery tungsten oxide formed on the tungsten silicide layer is directly influenced by not only hydrogen fluoride but also an upper film deposition temperature or a heat treatment temperature. That is, the outgassed tungsten oxide is recombined to form particles on the tungsten silicide layer when the gas is outgassed by high heat, and the wafers are arranged to face each other and the smooth flow of gas is disturbed. Form.

The thickness of the tungsten oxide and the silicon oxide formed on the tungsten silicide layer was measured by Transmission Electron Spectroscope (TEM), and particle analysis was performed by AES (Auger Electron Spectroscope). As a result of TEM after the deposition of the high temperature oxide film on the tungsten silicide layer, the silicon oxide was formed on the interface between the tungsten silicide layer and the high temperature oxide layer, and the powdered tungsten oxide was crystallized.

An object of the present invention is to solve the problems of the prior art to remove the tungsten oxide and silicon oxide generated on the surface of the tungsten silicide layer when the tungsten silicide layer is deposited to prevent particles generated when using a high temperature, It is to provide a high temperature oxide film deposition method on the tungsten silicide film.

1 is a process flowchart showing a method for depositing a high temperature oxide film on a tungsten silicide film according to a conventional method.

FIG. 2 is a schematic configuration diagram of a chamber showing a wafer arrangement state during heat treatment and deposition in a high temperature oxide film deposition method on a tungsten silicide film according to a conventional method.

3 is a process flowchart showing a method for depositing a high temperature oxide film on a tungsten silicide film according to the present invention.

4 is a schematic configuration diagram of a chamber showing a wafer arrangement state during heat treatment and deposition in a high temperature oxide film deposition method on a tungsten silicide film according to the present invention.

* Explanation of symbols for main parts of the drawings

30; Process chamber 32; Susceptor

34; wafer

The high temperature oxide film deposition method on the tungsten silicide film according to the present invention for achieving the above object is a step of depositing a tungsten silicide film on a wafer, after the deposition of the tungsten silicide film to arrange the wafer horizontally, the heat treatment Cleaning the wafer, and depositing a high temperature oxide (HTO) on the tungsten silicide layer by arranging the cleaned wafer horizontally.

SC-1 (Standard Chemical-1) may be used as the cleaning solution of the cleaning step.

The washing step may use a washing liquid in which sulfuric acid and hydrogen peroxide are mixed at a mixing ratio of 5 to 7: 1.

The washing step includes washing with a washing liquid mixed with sulfuric acid and hydrogen peroxide in a mixing ratio of 5 to 7: 1 and a washing liquid mixed with hydrogen fluoride and deionized water in a mixing ratio of 190 to 210: 1 and after washing, SC- 1 (Standard Chemical-1) it may comprise a step of repeated cleaning with a cleaning liquid.

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

3 is a process flowchart showing a high temperature oxide film deposition method on a tungsten silicide film according to the present invention.

As shown in FIG. 2, a tungsten silicide film is deposited on a wafer by chemical vapor deposition as the first tungsten silicide film deposition step. Next, as a heat treatment step, the composition is uniform after deposition and the resistance is minimized by having a stoichiometric ratio between tungsten and silicon. In other words, the grain size increases in the amorphous state where the grain size is small and changes from the hexagonal structure to the crystalline structure of the tetragonal structure. Decreases the resistance. The grain sizes are arranged in a uniform size and are typically maintained at 1000 mm 3 size. After the heat treatment, the sheet resistance is 2 to 3 Ω. It also improves adsorption properties and improves surface roughness. When the wafers are arranged vertically to face each other during the heat treatment process, the tungsten oxide outgassed by the high temperature is hindered by the vertical arrangement of the wafer to recombine with the wafer to form particles on the tungsten silicide layer. do.

4 is a schematic configuration diagram of a chamber showing a wafer arrangement state during heat treatment and deposition in a high temperature oxide film deposition method on a tungsten silicide film according to the present invention.

As shown in FIG. 4, the outgassed tungsten oxide should be smoothly removed by arranging the wafer 34 horizontally with respect to the susceptor 32 in the process chamber 30. Next, as a cleaning step, particles and impurities on the surface of the tungsten silicide layer are removed so that the upper layer to be deposited thereon is well deposited. The etchant used for the cleaning is SC-1 (Standard Chemical-1). Alternatively, the mixture is washed with an etchant in which hydrogen fluoride (HF) and deionized water are mixed at a mixing ratio of 200: 1, followed by washing with SC-1 (Standard Chemical-1) etchant. The tungsten silicide film reacts with hydrogen fluoride to form silicon oxide by tungsten oxide and surplus silicon, and as the cleaning time by hydrogen fluoride increases, the depth of penetration into the tungsten silicide film also increases to form thick silicon oxide and tungsten oxide. . Therefore, after washing with the aqueous hydrogen fluoride solution, must be re-washed with SC-1 to remove the powdered tungsten oxide.

Next, as the high temperature oxide film deposition step on the cleaned tungsten silicide layer, as shown in FIG. 4, the wafer 34 is arranged horizontally with respect to the susceptor 32 in the process chamber 30. That is, due to the trace amount of tungsten oxide remaining on the cleaned wafer, particle formation caused by tungsten oxide outgassing by the high temperature of 700 ° C. to 1000 ° C. during deposition of the high temperature oxide film is prevented in advance.

Therefore, according to the present invention, by modifying the arrangement and cleaning conditions of the wafer when forming the high temperature oxide film on the tungsten silicide film as described above, it is possible to prevent the generation of particles by the tungsten oxide formed on the tungsten silicide film to form a uniform high temperature oxide film It is effective to form.

Although the present invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the technical scope of the present invention, and such modifications and modifications are within the scope of the appended claims.

Claims (4)

In the method of depositing a high temperature oxide film on a tungsten silicide film in a semiconductor device manufacturing process, Depositing a tungsten silicide film on the wafer; Thermally arranging the wafers horizontally after depositing the tungsten silicide layer; Cleaning the heat-treated wafer; And Arranging the cleaned wafers horizontally to deposit the high temperature oxide (HTO) on a tungsten silicide layer; A high temperature oxide film deposition method on a tungsten silicide film comprising a. The method of claim 1, The cleaning solution of the cleaning step is SC-1 (Standard Chemical-1) characterized in that the high temperature oxide film deposition method on the tungsten silicide film. The method of claim 1, The cleaning step is a high temperature oxide film deposition method on the tungsten silicide film, characterized in that for using a cleaning solution mixed with sulfuric acid and hydrogen peroxide in a mixing ratio of 5 to 7: 1. The method of claim 1, The washing step may include washing with a washing liquid in which sulfuric acid and hydrogen peroxide are mixed at a mixing ratio of 5 to 7: 1, and a washing liquid mixed with hydrogen fluoride and deionized water at a mixing ratio of 190 to 210: 1; And Repeated washing with the SC-1 (Standard Chemical-1) cleaning solution after the cleaning; high temperature oxide film deposition method on the tungsten silicide film, characterized in that it comprises a.