JPH11204603A - Method for collecting a very small quantity of contaminant on surface of semiconductor wafer and contaminant collecting apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable analysis of a trace amount of contaminant on a surface of a semiconductor wafer with extreme high sensitively by using a trenched wafer as a contaminant collecting wafer, and increasing a contaminant collecting area to collect a trace amount of contaminant, with high yield. SOLUTION: A silicon wafer, a wafer oxidized with a surface, or a wafer formed with an SiO2 layer on a surface through chemical vapor deposition is formed as a trenched wafer with irregularities on a surface by photoetching. Since a wafer 4 is a trenched structure, a contaminant deposited area on the surface increases by several times. Then, a semiconductor process to be intended to detect contamination is processed by the trenched wafer 4, and a very small quantity of contaminant is deposited on the trenched wafer 4. Subsequently, a trace amount of the deposited contaminant 2 is analyzed by atomic absorption spectrophotometry and the like, and a trace amount of metallic element is detected. As a result, a trace amount of contaminant which could not be detected until now can be detected, since the contaminant deposition becomes double or more by the increase of the deposition area which is doubled or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for collecting contaminants when a semiconductor contaminant on a wafer surface is analyzed by atomic absorption spectrometry, ion chromatography, or high-frequency plasma emission mass spectrometry.

In particular, the present invention is characterized by providing high analytical sensitivity by efficiently recovering a small amount of contaminants.

[0003]

2. Description of the Related Art FIG. 2 shows a conventional method for collecting contamination on the surface of a semiconductor wafer.

FIG. 2A shows a mirror-like silicon mirror wafer (1 in FIG. 2) for collecting semiconductor contamination. Conventionally, using the above wafer, a semiconductor process in which contamination is to be detected is processed or left in a clean room environment in which contamination is to be detected, and trace contaminants (metals, ions, organic substances) (2 in FIG. 2) are adhered. Atomic absorption spectrometry was used to recover the attached trace contaminants into an acid solution such as hydrofluoric acid or nitric acid, and the solution (3 in FIG. 2) was analyzed to detect trace metal elements (FIG. 2 (b)). ).

Similarly, in the ion chromatography method, trace ions and trace organic ions are detected in pure water.

In the high-frequency plasma emission mass spectrometry, trace elements are recovered in an acid solution such as hydrofluoric acid or nitric acid and detected.

[0007] However, this method has a problem that as the cleanliness of the clean room, the manufacturing apparatus and the wafer surface increases, the amount of contamination adhering to the contamination recovery wafer is too small to be detected in the subsequent analysis.

In addition, the conventional silicon wafer surface collecting apparatus has a problem that as the degree of cleanliness of the environment increases, the amount of contamination required for detection in subsequent analysis does not adhere.

[0009]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a method for collecting contamination that can analyze very small amounts of contamination on the surface of a semiconductor wafer with extremely high sensitivity. Another object of the present invention is to provide a contamination recovery apparatus capable of recovering a minute amount of contamination on the surface of a silicon wafer at a high yield.

[0010]

According to a first aspect of the present invention, there is provided a method for collecting trace contamination on a wafer, wherein a trench-type wafer is used as a contamination collection wafer to increase the contamination collection area and to reduce the amount of trace contamination. It is characterized by being collected by. According to the present invention, the contamination recovery area is increased several times (depending on the aspect ratio of the trench-type wafer) as compared with the conventional mirror wafer, and the amount of contaminant attached is increased. It has the effect of being possible.

According to a second aspect of the present invention, there is provided a pollution recovery apparatus,
The present invention is characterized in that it is possible to increase the area for collecting contamination by using a trench-shaped wafer having irregularities and to collect trace contamination at a high yield. According to the present invention, the contamination recovery apparatus has a trench-type wafer structure, and thus has an effect of having a contaminated adhesion area several times (similar to the above) as compared with the related art.

[0012]

As described above, the use of the method and apparatus for collecting contamination on the surface of a semiconductor wafer according to the present invention makes it possible to more than double the detection sensitivity in the analysis of trace contamination of semiconductor contaminants.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.

First, a silicon wafer or a wafer whose surface has been oxidized, or SiO 2 by a chemical vapor deposition method
A wafer having _two layers formed on the surface is formed by photoetching into a trench type having an uneven surface (FIG. 1).
(A)). Since the wafer has a trench structure, the surface of the wafer has several times the contamination area (depending on the aspect ratio of the trench wafer) as compared with a conventional mirror-like mirror wafer.

Next, a semiconductor process in which contamination is to be detected is processed by the above-mentioned trench type wafer to attach a minute amount of contamination (FIG. 1B).

Subsequently, the adhered trace contaminants are recovered in an acid solution such as hydrofluoric acid or nitric acid by atomic absorption spectrometry, and the solution (3 in FIG. 1) is analyzed to detect a trace metal element (FIG. 1 ( c)).

Similarly, in the ion chromatography method, trace ions and trace organic ions are detected in pure water.

In the high frequency plasma emission mass spectrometry, trace elements are recovered in an acid solution such as hydrofluoric acid or nitric acid and detected.

In the subsequent analysis, the amount of adhered trace contamination that could not be detected below the lower limit of detection is increased by a factor of two or more, and the amount of adhesion is doubled and can be detected.

As a result, the qualitative and quantitative analysis of the contaminants on the wafer surface by the atomic absorption spectrometry, the ion chromatography, or the high-frequency plasma emission mass spectrometry can be improved.

The surface condition of the trench type wafer is S
Since it can take the form of i or SiO ₂ , it can be selected and used depending on the processing step or state.

[0022]

As described above, the use of the method and apparatus for collecting contamination on the surface of a semiconductor wafer according to the present invention makes it possible to more than double the detection sensitivity in the analysis of trace contamination of semiconductor contaminants.

[Brief description of the drawings]

FIG. 1 is a process chart showing an embodiment of collecting surface contamination using a trench wafer of the present invention.

FIG. 2 is a view showing a conventional silicon wafer surface contamination recovery method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mirror wafer 2 Trace contamination 3 Recovery solution 4 Trench type wafer

Claims (2)

[Claims] 1. A method of sampling semiconductor contaminants on a wafer, wherein a trench-type wafer is used as a wafer for contaminant recovery, wherein a contaminant recovery area is increased and microcontamination is recovered in a high yield. For collecting micro-pollutants. 2. A contaminant recovery apparatus for sampling a semiconductor contaminant, wherein a concavo-convex trench-type wafer is used, a contaminant recovery area is increased, and a very small amount of contaminants is recovered in a high yield. Pollution recovery equipment.