KR20080003616A - Silica slurry for chemical mechanical polishing semiconductor devices including hydro peroxide - Google Patents

Abstract

A silica slurry containing a hydro peroxide for CMP(Chemical Mechanical Polishing) of semiconductor devices is provided to reduce generation of organic defects and to improve productivity and yield of the semiconductor devices by making a silicon surface have hydrophilicity after completing the CMP. A silica slurry for CMP of semiconductor devices includes fumed silica particles. A wafer is introduced into a CMP equipment(S10). The wafer is polished by using the silica slurry containing a hydro peroxide(S20). The wafer is cleaned by using a cleaning solution containing hydrofluoric acid(S30). The wafer is cleaned by using deionized water(S40). The wafer is dried(S50). The wafer is withdrawn from the CMP equipment(S60). The fumed silica particles are 0.1 to 50 wt% of a total slurry. A silical particle is over 10 wt% of the total slurry. The hydro peroxide is 0.1 to 3 vol%.

Description

Silica slurry for chemical mechanical polishing semiconductor devices including hydro peroxide}

1 is a view illustrating a water droplet contact angle of a CMP silicon surface using a CMP poly slurry for a semiconductor device according to the prior art.

2 is a view illustrating a water droplet contact angle of a CMP silicon surface of a CMP silica slurry of a semiconductor device according to an embodiment of the present invention.

Figure 3 is a graph illustrating the removal rate of silicon after the CMP of the silicon surface while adjusting the hydrogen peroxide content of the silica slurry for CMP of the semiconductor device according to an embodiment of the present invention.

4 is a flowchart illustrating a method of performing a CMP process with a silica slurry for a semiconductor device CMP containing hydrogen peroxide according to an embodiment of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CMP slurry of a semiconductor device used in a semiconductor manufacturing process and a CMP method of a semiconductor device using the same. CMP method of the device.

The CMP process is a process of chemically and mechanically polishing a semiconductor substrate using a slurry containing an abrasive, in particular. The CMP process is excellent in planarization characteristics and is essential for the manufacturing process of highly integrated semiconductor devices. The CMP process includes a metal CMP process, a silicon nitride film CMP process, a silicon oxide film CMP process, a silicon CMP process, and other processes for polishing the film quality depending on the film quality to be polished.

In particular, the process of polishing silicon is cleaned with a cleaning solution containing hydrofluoric acid (HF) in the cleaning process that proceeds after polishing. The use of other cleaning solutions, SC-1 or ammonia water, can damage exposed metals, and ammonia water can damage silicon surfaces. Therefore, after polishing the silicon by the CMP process, it is generally cleaned with a cleaning solution containing hydrofluoric acid. By the way, after washing | cleaning with the cleaning solution containing hydrofluoric acid after a silicon CMP process, a silicon surface will become hydrophobic. When the polished silicon surface is hydrophobic, it becomes very difficult to remove organic defects generated in the CMP process or the like.

Typically, when cleaning the polished silicon surface with a hydrofluoric acid-containing cleaning solution, the silicon surface is treated with hydrofluoric acid, and then finally cleaned with deionized water, and the like. Cannot be cleaned properly.

In FIG. 1, when the silicon surface is hydrophobic, the contact angle θ1 between the water droplet and the silicon surface is illustrated. In general, the contact angle θ1 reaches about 52 °. The more hydrophobic the surface of the substrate, the larger the contact angle θ1.

In this case, an ashing step or a sulfuric acid cleaning step is further required to remove organic defects remaining on the silicon surface or the like. If the ashing process or sulfuric acid cleaning process is further performed, a separate cleaning device is needed, and the production time is delayed, resulting in low productivity and contamination of the cleaning device and the cleaning tank.

Therefore, after the silicon CMP process, measures to deal with the phenomenon that the silicon surface becomes hydrophobic are urgently needed.

An object of the present invention is to provide a silica slurry for CMP of a semiconductor device which makes the surface of the substrate hydrophilic after the CMP process.

Another object of the present invention is to provide a CMP method of a semiconductor device using a silica slurry for CMP of a semiconductor device to make the surface of the substrate hydrophilic after the CMP process.

Technical problems of the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

Silica slurry for CMP of a semiconductor device according to an embodiment of the present invention for achieving the above technical problem includes hydrogen peroxide.

The silica slurry for CMP of the semiconductor device may include fumed silica particles.

Fumed silica particles can be prepared by silicon oxidation in a hot gas phase.

The fumed silica particles may be contained in an amount of 0.1 to 50 wt% of the entire slurry, and in particular, 10 wt% or more.

Hydrogen peroxide may be contained in 0.01 to 3vol% of the total slurry, in particular 0.1 to 1vol%.

Hydrogen peroxide may be added in the liquid phase, and the pH concentration may be 11 or more.

Silica slurry for CMP of the semiconductor device of the present invention may be specifically for polishing the silicon surface.

CMP method of a semiconductor device according to an embodiment of the present invention for achieving the above another technical problem, the step of introducing a wafer into the CMP equipment, polishing the wafer using a silica slurry for CMP of the semiconductor device containing hydrogen peroxide Washing the wafer with a cleaning solution containing hydrofluoric acid, washing the wafer with deionized water, drying the wafer, and deriving the wafer from the CMP equipment.

Specific details of other embodiments are included in the detailed description and the drawings.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various forms. It is provided to fully convey the scope of the invention to those skilled in the art, and the present invention is defined only by the scope of the claims. In the drawings, the size and relative size of each component may be exaggerated for clarity.

Hereinafter, a CMP silica slurry of a semiconductor device according to an embodiment of the present invention will be described.

In the silica slurry for CMP of the semiconductor device according to the embodiment of the present invention, silica particles are used as an abrasive and include hydrogen peroxide.

The silica particles may be fumed silica particles. Fumed silica particles are silica particles that are produced using a silicon oxidation reaction in a hot gas phase. Compared with the silica particles produced by other methods, the composition is denser and harder, and the polishing rate is high, so that about 60% of the silicon oxide film may be polished when the silicon is polished. That is, the selectivity ratio of silicon to silicon oxide film is about 1: 0.6. More detailed methods of making fumed silica particles are well known and are therefore omitted.

The silica particles may be contained in an amount of 0.1 to 50 wt% of the entire slurry, and particularly may be contained in more than 10 wt%. Since the content of the silica particles is closely related to the removal rate of the film to be polished, too little or too much content is not good. If the content is too small, the polishing process is stable and the flattening uniformity of the polished film quality can be improved, but the polishing rate is lowered, resulting in lower productivity. On the contrary, when the content is large, the polishing rate is high, so that the productivity can be increased, but the flattening uniformity of the polished film quality is lowered, and scratches may occur on the film quality surface. In this embodiment, various experiments were carried out to contain 0.1 to 50 wt% of silica particles used as an abrasive, and in particular, experiments were carried out to contain 10 wt% or more. FIG. 2 is a diagram illustrating the results after performing the CMP process using the silica slurry for CMP, in which silica particles are contained in a proportion of 12 wt% of the total slurry. In the experimental results of this embodiment, the contact angle θ2 between the water droplet and the silicon surface is about 10 ° or less. In other words, it can be seen that the silicon surface is changed to hydrophilic.

Silica slurry for CMP of the semiconductor device according to an embodiment of the present invention contains hydrogen peroxide. Hydrogen peroxide may be added in the liquid phase, and may be added at 0.001 to 10 vol% of the total slurry. In this example, the experiment was performed by adding 0.1 vol%, and FIG. 2 is a diagram illustrating the result.

Table 1 illustrates various experimental results according to the content of hydrogen peroxide. More specifically, the CMP silica slurry of the semiconductor device including hydrogen peroxide according to various embodiments of the present invention is a result of counting defects such as particles and scratches on the surface of the silicon after CMP.

Content ratio (vol%) 0 0.1 0.3 0.7 1.0 particle - 5763 3270 2179 8194 scratch 69 2 48 60 67

Referring to Table 1, it can be seen that the number of particles and the number of scratches on the surface change according to the change in the content of hydrogen peroxide. When the content of hydrogen peroxide was 0%, the counting was meaningless because the number of particles was too large and was not written. Those who wish to implement the technical idea of the present invention will be able to further optimize through more various experiments.

Table 2 shows the hydrogen ion concentration (hereinafter referred to as pH) of the slurry according to the content ratio of hydrogen peroxide.

Content ratio (vol%) 0 One 3 pH 11.16 11.14 11.04

Referring to Table 2, it can be seen that the pH varies depending on the content of hydrogen peroxide, but there is no significant difference. Silica slurry for CMP of the semiconductor device according to an embodiment of the present invention may be strongly alkaline having a pH of 11 or more.

Based on the experimental results of Table 1 and Table 2, the silica slurry for CMP of the semiconductor device according to the embodiment of the present invention may contain hydrogen peroxide as 0.01 to 3vol% of the total slurry, in particular 0.1 to 1vol% have. In addition, the pH of the slurry may be 11 or more.

Silica slurries for CMP of semiconductor devices according to embodiments of the present invention are particularly useful for CMP of silicon. In general, the silica slurry is mainly used to CMP the silicon oxide film. In the case of polysilicon CMP slurry (hereinafter referred to as polyslurry), the silicon oxide film polishing rate is very inferior to that of silicon. Therefore, in the case of the poly slurry manufactured to contain hydrogen peroxide, which is the technical idea of the present invention, it may take longer to polish the silicon surface whose surface is oxidized.

Figure 3 is a graph showing the experimental results of performing the CMP process using a silica slurry for CMP of the semiconductor device containing hydrogen peroxide according to an embodiment of the present invention. Specifically, it is a graph showing the removal amount of silicon while adjusting the content of hydrogen peroxide. The X axis represents the hydrogen peroxide content, and the Y axis represents the amount of silicon removed per minute.

Referring to FIG. 3, it can be seen that the silicon removal amount decreases as the content of hydrogen peroxide increases. In addition, it can be seen that when the amount becomes about 0.3 vol% or more, the change in removal amount is rapidly decreased.

Therefore, those who wish to carry out the technical idea of the present invention, in the embodiment of the present invention described in detail herein in search of the optimum content in consideration of the particle prevention ability, scratch prevention ability, and reduction rate according to the content of hydrogen peroxide content I can make it.

4 is a view illustrating a process of CMP a wafer using a silica slurry for CMP of a semiconductor device containing hydrogen peroxide according to an embodiment of the present invention.

Referring to FIG. 4, a method of CMP a wafer using a silica slurry for CMP containing hydrogen peroxide according to an embodiment of the present invention includes introducing a wafer into a CMP apparatus (S10), and the wafer includes hydrogen peroxide. Polishing using a CMP silica slurry of a semiconductor device (S20), cleaning the wafer with a cleaning solution containing hydrofluoric acid (S30), cleaning the wafer with deionized water (S40), and drying the wafer. (S50), and the step of extracting the wafer from the CMP equipment (S60).

Although embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features thereof. I can understand that. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

As described above, when the silicon surface is CMP using the silica slurry for CMP of the semiconductor device containing hydrogen peroxide according to the embodiments of the present invention, the silicon surface becomes hydrophilic after CMP, and various defects including organic property defects are much higher. Less generation can significantly reduce productivity, yield and manufacturing cost of semiconductor devices.

Claims (20)

Silica slurry for CMP of a semiconductor device containing hydrogen peroxide. The method of claim 1, CMP silica slurry of the semiconductor device is a CMP silica slurry of a semiconductor device containing fumed silica particles. The method of claim 2, The fumed silica particles are silica slurry for CMP of a semiconductor device manufactured by a silicon oxidation reaction in a high temperature gas phase state. The method of claim 3, wherein The fumed silica particles are 0.1 to 50wt% of the total slurry of the silica slurry for CMP of the semiconductor device. The method of claim 4, wherein The silica particles are silica slurry for CMP 10wt% or more of the total slurry. The method of claim 1, The hydrogen peroxide is a silica slurry for CMP of the semiconductor device is 0.01 to 3vol% of the total slurry. The method of claim 6, The hydrogen peroxide is silica slurry for CMP of the semiconductor device is 0.1 to 1vol% of the total slurry. The method of claim 1, The hydrogen peroxide is a silica slurry for CMP of a semiconductor device is added in a liquid phase. The method of claim 1, CMP silica slurry of the semiconductor device is a CMP silica slurry of a semiconductor device having a pH concentration of 11 or more. The method of claim 1, Silica slurry for CMP of the semiconductor device is for polishing the silicon surface of the CMP silica slurry of the semiconductor device. Introducing the wafer into the CMP equipment, Polishing the wafer using a silica slurry for CMP of a semiconductor device including hydrogen peroxide, Cleaning the wafer with a cleaning liquid containing hydrofluoric acid, Cleaning the wafer with deionized water, Drying the wafer, and CMP method of a semiconductor device comprising the step of deriving the wafer from the CMP equipment. The method of claim 11, The CMP silica slurry of the semiconductor device comprises fumed silica particles CMP method of a semiconductor device. The method of claim 12, The fumed silica particles are a CMP method of a semiconductor device manufactured by a silicon oxidation reaction in a high temperature gas phase state. The method of claim 13, The fumed silica particles are 0.1 to 50wt% of the total slurry of the CMP method of the semiconductor device. The method of claim 14, The silica particles are CMP method of the semiconductor device is more than 10wt% of the total slurry. The method of claim 11, The hydrogen peroxide is CMP method of the semiconductor device is 0.01 to 3vol% of the total slurry. The method of claim 16, The hydrogen peroxide CMP method of the semiconductor device is 0.1 to 1vol% of the total slurry. The method of claim 11, The hydrogen peroxide is a CMP method of a semiconductor device is added in a liquid phase. The method of claim 11, CMP silica slurry of the semiconductor device is a CMP method of a semiconductor device having a pH concentration of 11 or more. The method of claim 11, The polishing step is a step of polishing a silicon surface CMP method of a semiconductor device.

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