KR20040077076A - Etching composition for silicon germanium of semiconductor device and etching method using the same - Google Patents

Abstract

PURPOSE: An etching composition for silicon germanium of a semiconductor device and an etching method using the same are provided to prevent damage of a silicon substrate and a silicon layer by removing selectively a silicon germanium layer. CONSTITUTION: A silicon germanium layer, a silicon layer, an oxide layer, and a silicon nitride layer are sequentially formed on a silicon wafer. The first opening region having a sidewall is formed by etching a part of the silicon nitride layer and each exposed part of the oxide layer, the silicon layer, and the silicon germanium layer. The sidewall of the first opening region includes the silicon layer pattern, the silicon germanium layer pattern, the oxide layer pattern, and the silicon nitride layer pattern. An SEG layer(140) is formed by filling up silicon into the first opening region. The second opening region(150) is formed by etching partially the exposed silicon wafer.

Description

Etching composition for silicon germanium of semiconductor device and etching method using same {{EFFECTING COMPOSITION FOR SILICON GERMANIUM OF SEMICONDUCTOR DEVICE AND ETCHING METHOD USING THE SAME}

The present invention relates to an etching composition for silicon germanium in a semiconductor device and an etching method using the same, and more particularly, to an etching composition for silicon germanium in a semiconductor device having a high etching selectivity of silicon germanium to silicon and an etching method using the same. .

In recent years, in an information society that is growing rapidly, semiconductor devices have been highly integrated in order to process large amounts of information faster with the development of various technologies. Thus, in order to form more patterns on the semiconductor substrate, there is a trend that the pattern spacing and pattern width are narrowing.

In particular, as the design rule of the semiconductor device is reduced to 100 nm or less, the space for forming a pattern is becoming narrower.

As such, while the size of the pattern is decreasing, electron mobility is very important for driving a highly integrated semiconductor device. In addition, when leakage current leaks from the source / drain regions formed in the semiconductor substrate to the lower portion of the substrate, a significant amount of current leaks from the entire semiconductor device, thereby lowering the operating speed of the semiconductor device as a whole.

Therefore, efforts have been made to prevent an electric current leaking into the lower portion by filling an insulating film in a semiconductor substrate. The buried insulating layer is located under the active region of the substrate, thereby preventing the electrons from moving downward when a channel is formed in the actual semiconductor device and the electrons move in the source / drain regions. The substrate having the buried insulating film is formed by forming a buried insulating film on a silicon wafer and growing silicon again on the buried insulating film. In general, silicon germanium is used as the buried insulation film.

In the case of forming a silicon nitride film or a silicon oxide film on a silicon wafer made of single crystal silicon, silicon germanium is used since single crystal silicon cannot be subsequently grown again.

As such, in order to selectively form the silicon germanium film in the active region of the substrate, the silicon germanium film should be etched with a higher etching selectivity than silicon. There is also a need for a way to eliminate this at a high selectivity.

In general, the most widely known selective etching liquid of silicon germanium is SC-1, and the wet etching method using the SC-1 may vary the selectivity of silicon germanium to silicon according to the use temperature and time. However, among the materials constituting the SC-1, the surface of the silylcon germanium film is rapidly oxidized due to HF, so that it is difficult to realize a selectivity of about 1:20 or more. Accordingly, when the SiGe is etched as desired, the loss of silicon is increased at the same time, so that the silicon germanium cannot be sufficiently etched, thereby limiting the process application.

Japanese Unexamined Patent Publication No. 13-148473 (hereinafter referred to as "quotation patent") discloses an etching method of silicon germanium. The cited patent etches silicon germanium using an etchant consisting of nitric acid, hydrofluoric acid and deionized water. However, in order to actually apply to the process, the selectivity of silicon germanium to silicon should be about 1: 100 or more, whereas the etchant of the cited patent has a selectivity of about 1: 2 in practice, There is a limit to. That is, in order to etch silicon germanium by a desired amount, silicon consumption is also increased to limit the implementation of selective etching. In addition, after the etching process, the continuous etching occurs during the transfer to the rinse process, causing unnecessary silicon loss.

Accordingly, it is a first object of the present invention to provide an etching composition having a high etching selectivity of silicon germanium to silicon by adjusting the ratio of deionized water to nitric acid, hydrofluoric acid and acetic acid.

A second object of the present invention is to provide an etching composition having a high etching selectivity of silicon germanium to silicon by adjusting the ratio of deionized water to nitric acid and hydrofluoric acid.

A third object of the present invention is to provide a method for selectively etching silicon germanium in a structure in which a silicon film and a silicon germanium film are laminated using an etching composition having a high etching selectivity of silicon germanium to silicon.

A fourth object of the present invention is to provide a method for selectively etching silicon germanium without damaging adjacent silicon films using an etching composition having a high etching selectivity of silicon germanium to silicon.

1A to 1D are cross-sectional views of a semiconductor device sample for describing an etching method according to an exemplary embodiment of the present invention.

2A is a cross-sectional SEM photograph of a semiconductor device sample according to Example 6 of the present invention.

2B is a cross-sectional SEM photograph of a semiconductor device sample according to Comparative Example 3 of the present invention.

<Explanation of symbols for the main parts of the drawings>

100 silicon wafer 110 silicon germanium film

110a: silicon germanium film pattern 120: silicon film

120a: silicon film pattern 123: oxide film

123a: oxide film pattern 126: silicon nitride film

126a: Silicon nitride film pattern 130: First opening region

140: SEG film 1 50: second opening area

In order to achieve the first object, the present invention is a semiconductor device consisting of a composition of 35.4 to 41.3 wt% nitric acid, 0.5 to 0.6 wt% hydrofluoric acid, 1.1 to 2.1 wt% acetic acid and 56 to 63 wt% deionized water It provides an etching composition for silicon germanium.

In order to achieve the second object, the present invention provides an etching composition for silicon germanium of a semiconductor device consisting of a composition of 35.4 to 41.3% by weight of nitric acid, 0.5 to 0.6% by weight of hydrofluoric acid and 49.1 to 65.4% by weight of deionized water. do.

In order to achieve the third object of the present invention, forming a silicon germanium film and a silicon film on a silicon substrate, etching a portion of the silicon germanium film, and sequentially etching the silicon film and a portion of the silicon substrate to Exposing a cross section of a silicon germanium film, a silicon film and a silicon substrate, 35.4 to 41.3 wt% nitric acid, 0.5 to 0.6 wt% hydrofluoric acid, 1.1 to 2.1 wt% acetic acid and 56 to 63 on the exposed silicon substrate Providing an etching composition comprising a first composition of wt% deionized water or a second composition of 35.4 to 41.3 wt% nitric acid, 0.5 to 0.6 wt% hydrofluoric acid and 49.1 to 65.4 wt% deionized water and the silicon germanium A silicon germanium etching chamber of a semiconductor device comprising etching the film faster than the silicon film and the silicon substrate. It provides.

In order to achieve the fourth object, the present invention includes forming an opening by etching a portion of the silicon substrate, embedding silicon germanium in the opening to form a silicon germanium film, and on the silicon substrate on which the silicon germanium film is formed. First composition of 35.4 to 41.3 wt% nitric acid, 0.5 to 0.6 wt% hydrofluoric acid, 1.1 to 2.1 wt% acetic acid and 56 to 63 wt% deionized water or 35.4 to 41.3 wt% nitric acid, 0.5 to 0.6 wt% It provides an etching composition consisting of a second composition of hydrofluoric acid and 49.1 to 65.4% by weight of deionized water, and etching the silicon germanium faster than the silicon.

As described above, by selectively removing the silicon germanium film without damaging the silicon, the silicon substrate or the silicon film can be prevented from being unnecessarily damaged to improve the yield of the semiconductor device.

Hereinafter, the present invention will be described in detail.

First, the first composition of the present invention comprises 35.4 to 41.3 wt% nitric acid, 0.5 to 0.6 wt% hydrofluoric acid, 1.1 to 2.1 wt% acetic acid and 56 to 63 wt% deionized water. When the nitric acid is less than about 35.4% by weight based on the total weight of the first composition, the etching time is delayed for application to a semiconductor process, and when the amount is greater than about 41.3% by weight, the etching time is shortened, but the selectivity of silicon germanium to silicon is reduced. Lowers. Accordingly, the nitric acid is preferably about 35.4 to 41.3 wt% based on the total weight of the first composition.

The hydrofluoric acid is a material for removing the oxide film formed on the surface of the silicon germanium during etching, preferably about 0.5 to 0.6% by weight based on the total weight of the first composition.

The acetic acid is a buffer material that selectively buffers silicon and silicon germanium, and if it is less than about 1.1 wt%, it is insufficient for buffering, and if it exceeds about 2.1 wt%, it is buffered even if the amount is increased. It is saturated with no change in action. Thus, the acetic acid is preferably about 1.1 to 2.1% by weight based on the total weight of the first composition.

The deionized water is a diluent capable of controlling the etching selectivity. When less than about 56% by weight, the silicon is excessively etched to lower the etching selectivity of silicon germanium to silicon. When the deionized water exceeds about 63% by weight, the etching time is excessive. Be delayed. Therefore, the deionized water is preferably about 56 to 63% by weight based on the total weight of the first composition.

The second composition of the present invention comprises 35.4 to 41.3 wt% nitric acid, 0.5 to 0.6 wt% hydrofluoric acid and 49.1 to 65.4 wt% deionized water. If the nitric acid is less than about 35.4% by weight relative to the total weight of the second composition, the etching time is delayed for application to the semiconductor process, and if it exceeds about 41.3% by weight, the etching selectivity of silicon germanium to silicon is lowered. Therefore, the nitric acid is preferably about 35.4 to 41.3% by weight based on the total weight of the second composition.

The hydrofluoric acid is a material for removing the oxide film formed on the surface of the silicon germanium during etching, preferably about 0.5 to 0.6% by weight based on the total weight of the second composition.

The deionized water is a diluent for controlling the etching selectivity. If less than about 49.1% by weight, the silicon is excessively etched to secure the selectivity of silicon germanium to silicon, and when it exceeds about 65.4% by weight, the etching time is increased. There is an excessive delay. Thus, the deionized water is preferably about 49.1 to 65.4% by weight relative to the total weight of the second composition.

The first and second compositions etch silicon germanium to silicon at a selectivity of at least about 1: 100. If the selectivity is less than about 1: 100, silicon is unnecessarily lost by etching up to silicon, which must remain unetched in an actual semiconductor process. Therefore, since the selectivity is insufficient to remove the silicon germanium film as desired, the selectivity is preferably about 1: 100 or more.

A method of preparing a sample for explaining a method of etching silicon germanium using the first and second compositions will be described.

1A to 1D are cross-sectional views of a semiconductor device sample for describing an etching method according to an exemplary embodiment of the present invention.

Referring to FIG. 1A, a silicon germanium film 110, a silicon film 120, an oxide film 123, and a silicon nitride film 126 are sequentially formed on the silicon wafer 100.

Referring to FIG. 1B, a portion of the silicon nitride film is etched and the exposed oxide film, the silicon film, and the silicon germanium film are sequentially etched to form a silicon film pattern 110a, a silicon germanium film pattern 120a, an oxide film pattern 123, and the like. A first opening region 130 exposing the top surface of the silicon wafer 100 is formed using the silicon nitride film pattern 126 as a sidewall.

Referring to FIG. 1C, the SEG film 140 is formed by filling the first opening region with silicon by selective epitaxial growth (SEG, hereinafter referred to as “SEG”).

Referring to FIG. 1D, the silicon nitride film pattern of the partial region spaced apart from the SEG film is etched, and the exposed oxide film pattern, the silicon film pattern, and the silicon germanium film pattern are sequentially etched. The second opening region 150 is formed by etching the exposed silicon wafer by etching the silicon germanium layer pattern.

Thus, the second opening region exposes the silicon nitride film pattern, the oxide film pattern, the silicon film pattern, the silicon germanium film pattern, and a cross section of the silicon substrate.

Another method for preparing a sample for explaining an etching method using the first composition and the second composition is to form a silicon film on a silicon substrate and to form an opening by etching a portion of the silicon film.

Silicon germanium is embedded in the opening to form a silicon germanium film. Therefore, both the silicon film and the silicon germanium film can be exposed on the upper surface.

As such, the etchant including the first composition or the second composition may be applied to a process of selectively etching the silicon germanium film formed adjacent to the single crystal silicon film.

Hereinafter, embodiments of the present invention will be described in detail.

The purity of nitric acid used was about 70%, the purity of hydrofluoric acid was about 50%, and the purity of acetic acid was about 99.9%.

Example 1

A composition comprising about 45.6% by weight of nitric acid, about 0.7% by weight of hydrofluoric acid, about 2.3% by weight of acetic acid and about 51.4% by weight of deionized water on a silicon wafer having a silicon film, a silicon germanium film and a cross section of the silicon wafer exposed. To provide an etching solution consisting of. At this time, the etchant was maintained at about 25 ℃, and overflowed (over-flow) for about 10 seconds.

Example 2

A composition comprising about 45.6% by weight of nitric acid, about 0.7% by weight of hydrofluoric acid, about 2.3% by weight of acetic acid and about 51.4% by weight of deionized water on a silicon wafer having a silicon film, a silicon germanium film and a cross section of the silicon wafer exposed. To provide an etching solution consisting of. At this time, the etchant was maintained at about 25 ℃, overflowed for about 20 seconds.

Example 3

A composition comprising about 45.6% by weight of nitric acid, about 0.7% by weight of hydrofluoric acid, about 2.3% by weight of acetic acid and about 51.4% by weight of deionized water on a silicon wafer having a silicon film, a silicon germanium film and a cross section of the silicon wafer exposed. To provide an etching solution consisting of. At this time, the etchant was maintained at about 25 ℃, overflowed for about 30 seconds.

Example 4

A composition comprising about 41.3 wt% nitric acid, about 0.6 wt% hydrofluoric acid, about 2.1 wt% acetic acid, and about 56 wt% deionized water on a silicon wafer having a silicon film, a silicon germanium film, and a cross section of the silicon wafer exposed. To provide an etching solution consisting of. At this time, the etchant was maintained at about 25 ℃, and overflowed for about 10 seconds.

Example 5

A composition comprising about 41.3 wt% nitric acid, about 0.6 wt% hydrofluoric acid, about 2.1 wt% acetic acid, and about 56 wt% deionized water on a silicon wafer having a silicon film, a silicon germanium film, and a cross section of the silicon wafer exposed. To provide an etching solution consisting of. At this time, the etchant was maintained at about 25 ℃, overflowed for about 20 seconds.

Example 6

A composition comprising about 41.3 wt% nitric acid, about 0.6 wt% hydrofluoric acid, about 2.1 wt% acetic acid, and about 56 wt% deionized water on a silicon wafer having a silicon film, a silicon germanium film, and a cross section of the silicon wafer exposed. To provide an etching solution consisting of. At this time, the etchant was maintained at about 25 ℃, overflowed for about 30 seconds.

Example 7

A composition comprising about 38.6 wt.% Nitric acid, about 0.6 wt.% Hydrofluoric acid, about 2 wt.% Acetic acid and about 58.8 wt.% Deionized water on a silicon wafer having a silicon film, a silicon germanium film and a cross section of the silicon wafer exposed. To provide an etching solution consisting of. At this time, the etchant was maintained at about 25 ℃, and overflowed for about 10 seconds.

Example 8

A composition comprising about 38.6 wt.% Nitric acid, about 0.6 wt.% Hydrofluoric acid, about 2 wt.% Acetic acid and about 58.8 wt.% Deionized water on a silicon wafer having a silicon film, a silicon germanium film and a cross section of the silicon wafer exposed. To provide an etching solution consisting of. At this time, the etchant was maintained at about 25 ℃, overflowed for about 20 seconds.

Example 9

A composition comprising about 38.6 wt.% Nitric acid, about 0.6 wt.% Hydrofluoric acid, about 2 wt.% Acetic acid and about 58.8 wt.% Deionized water on a silicon wafer having a silicon film, a silicon germanium film and a cross section of the silicon wafer exposed. To provide an etching solution consisting of. At this time, the etchant was maintained at about 25 ℃, overflowed for about 30 seconds.

Example 10

An etchant consisting of a composition comprising about 41.3 wt% nitric acid, about 0.6 wt% hydrofluoric acid, and about 58.1 wt% deionized water was provided on a silicon wafer having a silicon film, a silicon germanium film, and a cross section of the silicon wafer exposed. At this time, the etchant was maintained at about 25 ℃, and overflowed for about 10 seconds.

Example 11

An etchant consisting of a composition comprising about 41.3 wt% nitric acid, about 0.6 wt% hydrofluoric acid, and about 58.1 wt% deionized water was provided on a silicon wafer having a silicon film, a silicon germanium film, and a cross section of the silicon wafer exposed. At this time, the etchant was maintained at about 25 ℃, overflowed for about 20 seconds.

Example 12

An etchant consisting of a composition comprising about 41.3 wt% nitric acid, about 0.6 wt% hydrofluoric acid, and about 58.1 wt% deionized water was provided on a silicon wafer having a silicon film, a silicon germanium film, and a cross section of the silicon wafer exposed. At this time, the etchant was maintained at about 25 ℃, overflowed for about 30 seconds.

Comparative Example 1

A composition comprising about 49.5% by weight of nitric acid, about 0.7% by weight of hydrofluoric acid, about 2.5% by weight of acetic acid and about 47.3% by weight of deionized water on a silicon wafer having a silicon film, a silicon germanium film and a cross section of the silicon wafer exposed. To provide an etching solution consisting of. At this time, the etchant was maintained at about 25 ℃, and overflowed for about 10 seconds.

Comparative Example 2

A composition comprising about 49.5% by weight of nitric acid, about 0.7% by weight of hydrofluoric acid, about 2.5% by weight of acetic acid and about 47.3% by weight of deionized water on a silicon wafer having a silicon film, a silicon germanium film and a cross section of the silicon wafer exposed. To provide an etching solution consisting of. At this time, the etchant was maintained at about 25 ℃, overflowed for about 20 seconds.

Comparative Example 3

A composition comprising about 49.5% by weight of nitric acid, about 0.7% by weight of hydrofluoric acid, about 2.5% by weight of acetic acid and about 47.3% by weight of deionized water on a silicon wafer having a silicon film, a silicon germanium film and a cross section of the silicon wafer exposed. To provide an etching solution consisting of. At this time, the etchant was maintained at about 25 ℃, overflowed for about 30 seconds.

Etch amount comparison test by wet etching

The samples prepared in Examples 1 to 12 and Comparative Examples 1 to 3 were cut in a second cross section direction perpendicular to the first cross section exposing the silicon film, the silicon germanium film, and the silicon wafer. The second section of the cut sample was observed with a vertical scanning electron microscope (SEM) image.

When silicon germanium is grown on single crystal silicon, the silicon germanium is strained and grown by lattice constant difference. The thickness measurement by the optical method uses an optical constant (nk) which varies with the degree of deformation and the impurity concentration, but since the difference between the optical constants of silicon and silicon germanium is not large, optical thickness measurement is practically impossible. Do. In addition, the modified silicon germanium grown on the silicon is limited in thickness by which the germanium concentration can grow, so that a general profile meter cannot be used. Therefore, the difference in etching amount was measured by SEM photograph.

Si etching amount SiGe etching amount Selection ratio Example 1 2.7 2740 1014 Example 2 15 5520 368 Example 3 35 9800 280 Example 4 0 1308 1308 Example 5 5 1860 372 Example 6 11 2964 269 Example 7 0 324 324 Example 8 2.1 707 336 Example 9 6.4 988 154 Example 10 0 1286 1286 Example 11 5 1856 371 Example 12 10 2935 293 Comparative Example 1 110 4950 45 Comparative Example 2 237 - - Comparative Example 3 346 - -

Comparative examination of membrane damage by wet etching

The cut surfaces of the samples prepared in Examples 1 to 12 and Comparative Examples 1 to 3 were observed with a vertical scanning electron microscope (SEM) photograph.

Si film surface Membrane deviation Example 1 ○ None Example 2 ○ None Example 3 ○ None Example 4 ○ None Example 5 ○ None Example 6 ○ None Example 7 ○ None Example 8 ○ None Example 9 ○ None Example 10 ○ None Example 11 ○ None Example 12 ○ None Comparative Example 1 × Occur Comparative Example 2 × Occur Comparative Example 3 × Occur

Legend: Good, Bad X, not evaluated.

○: Silicon surface is not eroded or damaged and morphology is uniform

X: The silicon surface is partially eroded or damaged and the morphology is uneven

Referring to Table 1, the composition used in Examples 1 to 12 was found that the etching selectivity of silicon germanium to silicon is about 1: 100 or more. In particular, in the case of Examples 4, 7, and 10, the etching selectivity to silicon germanium was very high so that the amount of etching of the silicon was little. Therefore, the etching selectivity required in the manufacturing process of the semiconductor device was met.

On the other hand, the etching selectivity of Comparative Example 1 was about 1:45, which was very low. In addition, in Comparative Examples 2 and 3, not only the etching amount of silicon increased sharply, but also the etching amount of silicon germanium was excessively excessive, which cannot be observed in the enlarged photograph of the SEM image. Therefore, not only the etching selectivity does not meet the process conditions, but also the amount of etching of silicon germanium and the amount of etching of silicon may cause defects in the semiconductor device.

2A is a cross-sectional SEM photograph of a semiconductor device sample according to Example 6 of the present invention.

2A and 2, when the composition of Example 6 was used, the surface state of the exposed silicon substrate was good. In addition, only the layer where the silicon germanium to be etched is etched, and the films above and below the silicon germanium film were stably present.

2B is a cross-sectional SEM photograph of a semiconductor device sample according to Comparative Example 3 of the present invention.

Referring to Figure 2b and Table 2, when using the composition of Comparative Example 3 it was confirmed that the surface of the exposed silicon substrate is damaged and the morphology is very low. In addition, the etching amount of the silicon germanium film was so excessive that it was not possible to confirm the silicon germanium film remaining on the SEM photograph, and not only the silicon germanium film but also other films located thereon were etched away from the silicon nitride film thereon. Lifting phenomenon occurred.

As a result, it can be seen that the weight of deionized water relative to the total weight of the composition acts as an important factor for the etching selectivity. That is, even when using the same composition, the weight ratio of the used composition played an important role in determining the etching selectivity. In addition, the etching amounts of silicon and silicon germanium also changed with respect to the etching time.

As the weight ratio of deionized water increased, the etching amount of each of silicon and silicon germanium decreased, and when using the composition having the same weight ratio of deionized water, the etching amount increased linearly with longer etching progression time.

Etching was performed at room temperature (approximately 25 ° C) to verify the validity of the process application.

As described above, according to the present invention, when the silicon film and the silicon germanium film are formed adjacent to each other, the silicon germanium film is etched at a high selectivity by a composition in which the concentrations of nitric acid, hydrofluoric acid, acetic acid and deionized water are adjusted. Therefore, during the etching of the silicon germanium film, the silicon film could not be damaged.

As described above, by selectively removing the silicon germanium film without damaging the silicon, the silicon substrate or the silicon film can be prevented from being unnecessarily damaged to improve the yield of the semiconductor device.

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified without departing from the spirit and scope of the invention described in the claims below. And can be changed.

Claims (13)

An etching composition for silicon germanium in a semiconductor device consisting of 35.4 to 41.3 wt% nitric acid, 0.5 to 0.6 wt% hydrofluoric acid, 1.1 to 2.1 wt% acetic acid, and 56 to 63 wt% deionized water. The etching composition of claim 1, wherein the composition etches silicon germanium in a selectivity ratio of 1: 100 or more with respect to silicon. An etching composition for silicon germanium of a semiconductor device, comprising a composition of 35.4 to 41.3 wt% nitric acid, 0.5 to 0.6 wt% hydrofluoric acid, and 49.1 to 65.4 wt% deionized water. The etching composition of claim 3, wherein the composition etches silicon germanium with respect to silicon at a selectivity of at least 1: 100. 5. Forming a silicon germanium film and a silicon film on the silicon substrate; Etching a portion of the silicon germanium film and sequentially etching a portion of the silicon film and the silicon substrate to expose cross sections of the silicon germanium film, the silicon film, and the silicon substrate; A first composition of 35.4 to 41.3 wt% nitric acid, 0.5 to 0.6 wt% hydrofluoric acid, 1.1 to 2.1 wt% acetic acid and 56 to 63 wt% deionized water or 35.4 to 41.3 wt% on the exposed silicon substrate Providing an etchant consisting of a second composition of nitric acid, 0.5-0.6 weight percent hydrofluoric acid and 49.1-65.4 weight percent deionized water; And Etching the silicon germanium film faster than the silicon film and the silicon substrate. The method of claim 5, wherein the silicon germanium layer is etched at least 100 times faster than the silicon layer and the silicon substrate. 6. The method of claim 5, further comprising forming an oxide film and a nitride film after the forming of the silicon film. 7. The method of claim 5, wherein the etching comprises: Silicon germanium etching method of a semiconductor device, characterized in that proceeding at 20 to 30 ℃. The method of claim 5, wherein the forming of the silicon germanium film and the silicon film, Forming a silicon germanium film on the silicon substrate; Forming a silicon film on the silicon germanium film; Etching portions of the silicon film and the silicon germanium film to form openings exposing an upper surface of the silicon substrate; And Silicon germanium etching method of the semiconductor device comprising the step of filling the opening with silicon. Etching a portion of the silicon substrate to form an opening; Embedding silicon germanium in the opening to form a silicon germanium film; The first composition of 35.4 to 41.3 wt% nitric acid, 0.5 to 0.6 wt% hydrofluoric acid, 1.1 to 2.1 wt% acetic acid and 56 to 63 wt% deionized water or 35.4 to 41.3 on the silicon substrate on which the silicon germanium film is formed Providing an etchant consisting of a second composition of wt% nitric acid, 0.5 to 0.6 wt% hydrofluoric acid and 49.1 to 65.4 wt% deionized water; And And etching the silicon germanium faster than the silicon. The method of claim 10, wherein the silicon germanium is etched at least 100 times faster than the silicon. The method of claim 10, wherein the etching comprises: Silicon germanium etching method of a semiconductor device, characterized in that proceeding at 20 to 30 ℃. The silicon germanium etching method of claim 10, further comprising a silicon film on the silicon substrate.