JP2011110616A - Polishing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To independently treat a sample piece after the sample piece is polished while restraining damage on a polishing cloth used for polishing. <P>SOLUTION: A coating material 103 formation face of a base 101 is brought into contact with a polishing cloth and polished, and the coating material 103 on a top of a sample piece 102 is removed to expose a surface 121, which is a polishing object of the sample piece 102. Sequentially, the surface 121 of the sample piece 102 exposed by removing the coating material 103 is brought into contact with the polishing cloth fixed to a rotating polish plate, so as to polish the surface 121 of the sample piece 102. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a polishing method for polishing a surface of a sample to be observed, for example, for surface observation.

  In the analysis of a solid sample, the surface of the sample is polished to a mirror surface, the obtained mirror surface is processed by chemical modification or the like, and then the processed surface is observed with a microscope or the like. Moreover, the composition of the location determined by the result of this observation is analyzed by, for example, SIMS (Secondary Ion-microprobe Mass Spectrometry). Such an analysis is important in conducting research on electronic devices and semiconductor materials.

  In the above-described polishing of the sample, a polishing apparatus using various polishing cloths is generally used. As shown in FIGS. 2A and 2B, this polishing apparatus is configured such that a polishing cloth 201 containing an abrasive is fixed to a polishing board 202 and the polishing board 202 rotates. A sample holder 203 that rotates is disposed on the polishing board 202, and the sample 204 to be polished is fixed to the sample holder 203. In this polishing apparatus, the pressure is applied to the pressure unit 205 of the sample holder 203 to which the sample 204 is fixed, and the polishing cloth 201 fixed to the rotating polishing disk 202 is brought into contact with the polishing symmetry surface of the sample 204 for polishing. (Refer nonpatent literature 1). In addition, in this apparatus, the water supply part 206 is provided and water supply is possible to the area | region where the grinding | polishing board 202 is installed.

  Here, the sample to be analyzed as described above is a small sample piece with a dimension of several millimeters, and in this state, it is not easy to fix it to the sample holder. For this reason, as is well known, a minute sample piece is embedded in a resin or the like, the resin is molded into a cylindrical shape or the like, and polished together with a molded body of the resin. Thus, by handling the sample piece sealed in the resin molded body, for example, it becomes possible to make the object to be polished a dimension that can be mounted on the polishing apparatus.

  By the way, the resin used for sealing the sample piece has strength and resistance such that it can withstand the polishing operation attached to the sample holder. Therefore, it is not easy to remove the resin used for sealing from the sample piece. For this reason, surface observation of the sample after sample preparation processing such as polishing is performed in a state where the sample piece is sealed in the resin molded body. However, when a measurement device or an analysis device used for observation or the like is intended for a small sample piece having a size of about several millimeters, it can be attached to the device in a state where it is sealed in a resin body as described above. become unable.

  In order to solve the above problems, a method has been proposed in which a fine sample piece is bonded and fixed to a support such as glass and the sample piece is polished by holding the support (see Non-Patent Document 2). According to this method, after the sample piece is polished, it can be removed from the support, and measurement and analysis can be performed with an apparatus that is intended for a small sample piece.

Automatic polishing equipment catalog, “Ecomet 250 + Automet 250 Ecomet 300 + Automet 300”, Sankei Co., Ltd. Tomohiro Haraguchi, “Mechanical Polishing of Semiconductor Materials—Toward Preparation of TEM Samples”, 2006 Miyazaki University Faculty of Engineering Education Research Support Technology Center, Technical Center Report vol. 4, 2006.

  However, in the above-described technique, since the sample piece is not embedded, for example, when the shape of the sample piece is approximately a rectangular parallelepiped, the side surface (end face) perpendicular to the polishing surface of the sample piece is exposed and provided. become. Here, in the polishing using the moving (rotating) polishing cloth, for example, the polishing cloth just before entering the polishing surface of the sample piece is bent as well known. When the location where the polishing cloth is bent in this way enters the edge of the sample piece having an end surface perpendicular to the polishing surface, the polishing cloth is applied to the edge, and the sample piece and the polishing cloth are The smooth sliding between them may be hindered, and the polishing cloth may be damaged.

  On the other hand, when the sample piece is sealed with resin and polished as described above, the end portion of the resin molded body can be chamfered, and the load on the polishing cloth can be suppressed. Further, since the sample piece is embedded in the resin molded body, the edge portion does not occur on the polishing cloth. However, as described above, when a sample is sealed and polished in a resin molded body, it is not easy to handle a sample piece alone after polishing.

  The present invention has been made to solve the above-described problems, and after the sample piece is polished in a state where damage to the polishing cloth used for polishing is suppressed, the sample piece can be handled alone. The purpose is to do so.

  The polishing method according to the present invention includes a first step of placing a sample on a sample fixing portion of a base, a second step of covering and wrapping the sample placed on the sample fixing portion with a covering material, and a rotating polishing plate A third step in which the covering material forming surface of the base is brought into contact with a fixed polishing cloth containing an abrasive to remove the covering material on the top of the sample to expose the surface of the sample; and the covering material is removed The surface of the exposed sample is brought into contact with a polishing cloth fixed to a rotating polishing plate, and at least a fourth step of polishing the surface of the sample, and the covering material is made of a material that is polished together with the sample by polishing. The covering material is made of a material that does not cause a chemical reaction with the sample, and the covering material is made of a material that melts by at least one of heating and chemical reaction in a range where the sample does not change.

  As described above, according to the present invention, since the sample is coated with a removable covering material and then polished, the polishing is performed in a state where the occurrence of damage to the polishing cloth used for polishing is suppressed. The excellent effect of being able to handle the sample piece alone is obtained.

It is process drawing explaining the grinding | polishing method in embodiment of this invention. It is process drawing explaining the grinding | polishing method in embodiment of this invention. It is process drawing explaining the grinding | polishing method in embodiment of this invention. It is process drawing explaining the grinding | polishing method in embodiment of this invention. It is explanatory drawing which shows the structure of a grinding | polishing apparatus. It is a top view which shows the partial structure of a grinding | polishing apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1A to 1D are process diagrams for explaining a polishing method according to an embodiment of the present invention. 1A to 1D schematically show cross sections. First, as shown in FIG. 1A, the sample piece 102 is arranged on the sample fixing portion (sample fixing surface) 111 of the base 101. The base 101 can be made of a material such as metal, plastic, glass, or ceramic, for example. Further, for example, the sample piece 102 may be bonded and fixed to the sample fixing portion 111 with a wax often used for bonding the object to be polished to the holder by polishing or the like.

  Next, as shown in FIG. 1B, the sample piece 102 arranged in the sample fixing unit 111 is covered with a covering material 103 and wrapped. Here, as shown in FIG. 1B, it is important that the covering material 103 is formed in a shape having a curved surface and no protrusions. It is important that the covering material 103 is made of a material that is polished together with the sample piece 102 by polishing. It is important that the covering material 103 is made of a material that does not cause a chemical reaction with the sample piece 102.

  In addition, it is important that the covering material 103 is made of a material that can be melted by at least one means of heating temperature and chemical reaction within a range where the sample piece 102 does not change. For example, the covering material 103 may be made of metal gallium, an alcohol wax that softens at 55 ° C., a Sn / 57Bi / 26In alloy (solder material) having a melting point of 75 ° C., or the like.

  For example, when gallium is used, the covering material 103 is dissolved by heating to about 28 ° C. or higher, which is the melting point of gallium. When such a low-melting-point metal is used as the covering material 103, it is important to maintain the ambient temperature at 20 ° C. or lower so that the covering material 103 does not melt in the following steps such as polishing. On the other hand, when the above-described alcohol wax or solder material is used, it is not necessary to reduce the ambient temperature so much in a process such as polishing.

  Next, using a polishing apparatus (see Non-Patent Document 1), the surface of the base 101 on which the coating material 103 is formed is brought into contact with a polishing cloth fixed on a rotating polishing plate and containing an abrasive, and then polished. Thus, as shown in FIG. 1C, the covering material 103 on the upper part of the sample piece 102 is removed, and the surface 121 of the sample piece 102 to be polished is exposed. In this polishing, the purpose is to expose the surface 121, and it is preferable that the particle size of the abrasive is coarse and the polishing rate is high. Here, since the covering material 103 has a curved surface and does not include an edge (projection) having an angle that damages the polishing cloth, the polishing cloth is not damaged in this polishing. .

  Subsequently, the surface 121 of the sample piece 102 exposed by removing the covering material 103 is brought into contact with a polishing cloth fixed to a rotating polishing plate, and the surface 121 of the sample piece 102 is polished. In this polishing, the particle size of the abrasive is gradually reduced to shift from rough polishing to final finish polishing (mirror polishing).

  Here, in the state where the surface 121 is exposed, the exposed surface 121 and the polishing surface 131 of the covering material 103 are continuously present, and a surface continuous with the surface 121 and the polishing surface 131 is formed. Therefore, the polishing surface 131 of the covering material 103 functions as a guide surface with respect to the relatively moving polishing cloth, and the polishing cloth passes through the edge of the sample piece 102 without bending. And slide with the surface 121. Moreover, the side part (side surface) with respect to the surface 121 of the sample piece 102 is covered with the coating | covering material 103, and does not touch polishing cloth. Therefore, according to the present embodiment, damage to the polishing cloth at the edge of the sample piece 102 is suppressed.

  As described above, the surface 121 to be polished of the sample piece 102 is polished to a desired state, and then the covering material 103 is removed. For example, when the covering material 103 is made of gallium, since the melting point of gallium is 28 ° C., it may be heated to about 30 ° C., for example. By this heating, the covering material 103 is dissolved and removed, and as shown in FIG. 1D, only the sample piece 102 is placed in the sample fixing portion 111. Thereafter, the sample piece 102 is removed from the sample fixing portion 111 by washing with an alcohol-type agent such as ethanol, an aromatic solvent, and a water-soluble detergent and dissolving the adhesive (wax). As described above, according to the present embodiment, the sample piece 102 can be easily detached, and the polished sample piece 102 can be handled independently, and analysis using various analyzers can be performed.

  It should be noted that the present invention is not limited to the embodiment described above, and that many modifications can be implemented by those having ordinary knowledge in the art within the technical idea of the present invention. It is obvious. For example, the sample pieces are various solid materials such as ceramic, glass, metal (alloy), and semiconductor. The material used for the coating material is not limited to gallium, alcohol wax, and solder material. The material is polished together with the sample by polishing and does not cause a chemical reaction with the sample. It should just be comprised from the material which can be melt | dissolved by at least one.

  The material that dissolves by a chemical reaction is, for example, a material that dissolves in a solution such as a solvent (solvent) in which a sample does not dissolve and an acid. For example, if a resin that dissolves in a solvent that does not dissolve the sample is used as the coating material, the coating material can be removed from the sample by dissolution using a solvent. Further, for example, when a metal material that dissolves in an acid that does not dissolve the sample is used as the coating material, the coating material can be removed from the sample by dissolution using an acid.

  In addition, it is important that the coating material has a hardness enough to be polished together with the sample by polishing, but if the hardness is too low, the coating material is peeled off. Therefore, the coating material needs to have a hardness that does not peel off during polishing. Among these, it is preferable that the coating material has the same hardness as the sample.

  DESCRIPTION OF SYMBOLS 101 ... Base, 102 ... Sample piece, 103 ... Covering material, 111 ... Sample fixing | fixed part, 121 ... Surface, 131 ... Polishing surface.

Claims (1)

A first step of placing a sample on the sample fixing portion of the base;
A second step of covering and wrapping the sample arranged in the sample fixing part with a covering material;
The covering material forming surface of the base is brought into contact with a polishing cloth fixed on a rotating polishing plate and containing an abrasive to remove the covering material on the top of the sample to remove the surface of the sample. A third step of exposing;
And at least a fourth step of abutting the surface of the sample exposed by removing the covering material with the polishing cloth fixed to the rotating polishing plate and polishing the surface of the sample,
The covering material is composed of a material that is polished together with the sample by the polishing,
The covering material is composed of a material that does not cause a chemical reaction with the sample,
The said covering material is comprised from the material melt | dissolved by at least 1 of the heating of the temperature of the range which does not change the said sample, and a chemical reaction. The polishing method characterized by the above-mentioned.