TWI617809B - Method of examining quality of silicon material - Google Patents

Abstract

The invention relates to a method for testing the quality of a raw material, comprising the steps of: providing a raw material; immersing the raw material in an acid solution, dissolving the surface layer of the raw material in the acid solution, and leaving the remaining portion of the raw material undissolved Extracting from the acid solution; taking a portion of the acid solution in which the surface layer of the niobium material is dissolved, and detecting the metal content in the acid solution taken; determining the grade of the niobium material as a plurality of predetermined grades according to the detected metal content One of them. Thereby, the quality of the raw material can be quickly and accurately determined.

Description

检验Test method for raw material quality

The invention relates to the quality inspection of bismuth raw materials; in particular to a method for testing the quality of bismuth raw materials.

The twins are made of tantalum raw materials. The conventional methods for casting twins include CZ and directional solidification. No matter which method is used to cast the twins, they are all after the casting. The detection device detects the carrier lifetime of the wafer and the distribution of the red zone in the life map of the carrier to evaluate the quality of the wafer. The aforementioned red region is a region in which metal is concentrated in the germanium, and the carrier life in the red region is relatively low.

However, in addition to the process conditions in the casting process, the quality of the raw materials in the casting process is one of the main factors affecting the quality of the twins. At present, the manufacturers of crystal enamel are buying a large amount of bismuth raw materials, and then sampling the raw materials into crystal slabs, and then pushing the quality of the raw materials by the quality of the enamel. However, it takes a long time to melt the raw material and then solidify it into crystals. The quality of the raw materials in the above-mentioned manner will make the time for testing the quality of the raw materials excessive. In addition, the quality of the raw materials is uneven. If the raw materials with better quality and poor quality are taken at the same time, the overall quality of the crystals will be degraded. When the quality of the raw materials is reversed, the quality will be better.矽 Raw materials are misjudged as poor quality.

In view of the above, an object of the present invention is to provide a method for testing the quality of a raw material of tantalum, which can effectively reduce the time for judging the quality of the raw material.

In order to achieve the above object, the present invention provides a method for testing the quality of tantalum raw materials, comprising the steps of: A, providing a raw material; B, immersing the raw material in an acid solution, so that the surface layer of the raw material is dissolved in After the acid solution, the remaining portion of the ruthenium raw material that has not been dissolved is taken out from the acid solution; C, a portion of the acid solution in which the surface layer of the ruthenium raw material is dissolved in step B is taken, and the metal content in the acid solution taken is detected. D, determining the grade of the tantalum raw material according to the metal content detected in step C is one of a plurality of predetermined levels.

The effect of the present invention is that the level of the bismuth raw material can be determined by detecting the metal content in the acid solution in which the surface layer of the bismuth raw material is dissolved, and the quality of the bismuth raw material can be determined quickly and accurately. Quality, effectively reducing the time to judge the quality of raw materials.

〔this invention〕

S101~S105‧‧‧Steps

S201~S204‧‧‧Steps

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a flow chart showing the quality of a raw material in accordance with a preferred embodiment of the present invention for detecting the quality of the raw material.

Figure 2 is a flow chart showing the quality of another crucible material in the preferred embodiment described above.

Fig. 3 is a diagram showing the life-time mapping of the wafers of the first-stage tantalum raw material cast in the above preferred embodiment.

Fig. 4 is a view showing the carrier life of the wafer of the second stage of the above-described preferred embodiment.

Fig. 5 is a view showing the carrier life of the wafer of the third stage of the above-described preferred embodiment.

In order to explain the present invention more clearly, a preferred embodiment will be described in detail with reference to the drawings. Referring to FIG. 1 and FIG. 2, a flow chart of a method for testing the quality of a raw material according to a preferred embodiment of the present invention includes the following steps: in step S101, a raw material is obtained, and the raw material includes at least one A block can also be a plurality of blocks. The raw material taken is washed to remove impurities on the surface of the tantalum raw material. In the embodiment, the step of washing is to immerse the niobium raw material in a first acid liquid, wherein the first acid liquid comprises hydrofluoric acid and nitric acid. However, not limited thereto, the first acid solution may be acetic acid, sulfuric acid, hydrochloric acid, phosphoric acid or the like. Thereafter, the ruthenium raw material is taken out from the first acid liquid, placed in the deionized water, and washed in an overflow manner.

Step S102, providing a second acid solution, and taking a portion of the metal content in the second acid solution to obtain a background value. In this embodiment, an Inductively Couple Plasma Optical Emission Spectrometer (Inductively Couple Plasma Optical Emission Spectrometry, ICP/OES) detects metal content. In this embodiment, the second acid solution comprises hydrofluoric acid and nitric acid, and the ratio is 1:11, but not limited thereto. In the implementation, the second acid solution may also be acetic acid, sulfuric acid, hydrochloric acid, phosphoric acid or the like. The metal component among the detected metal contents includes at least one of iron (Fe), aluminum (Al), copper (Cu), and magnesium (Mg), and the metal components detected in the present example are Ag, Al, and B. , Ba, Bi, Ca, Cd, Co, Cr, Cu, Fe, Ga, In, K, Li, Mg, Mn, Na, Ni, Pb, Sr, Tl, Zn.

Step S103, immersing the cleaned raw material in the second acid solution, dissolving the surface layer of the tantalum raw material in the second acid liquid, and oxidizing the surface layer of the tantalum raw material into cerium oxide by nitric acid, and then using hydrogen The characteristics of the ceric acid corroding cerium oxide dissolve the cerium oxide, thereby dissolving the metal impurities in the surface layer of the cerium material together in the second acid liquid. The remainder of the bismuth material that has not been dissolved is then removed from the second acid solution. The extracted raw material is then placed in the deionized water and washed in an overflow manner for casting into a wafer. The time for the bismuth raw material to be immersed in the second acid liquid is at least 5 minutes, and the metal content dissolved in the embodiment for 10 to 15 minutes and immersed for 5 minutes or more can correspond to the quality of the final casting into a crystal crucible.

Step S104, taking a portion of the second acid solution in which the surface layer of the niobium material is dissolved in step S103, and detecting the metal content in the second acid solution taken. In this embodiment, the inductively coupled plasma emission spectrometer is also used. The metal content is detected, and the detected metal component is the same as step S102.

Step S105, determining, according to the metal content detected in step S104, the level of the niobium material is one of a plurality of predetermined levels, the predetermined levels being predefined, and the predetermined levels are at least two levels, In the embodiment, the predetermined grades are three grades, which are first to third grades respectively, wherein the quality of the first grade of tantalum raw material is the highest, the quality of the second grade of tantalum raw material is second, and so on. Since the metal content has an effect on the carrier lifetime of the crucible material being cast into a crucible, the definition of the predetermined grade is mainly determined by the amount of total metal content. In addition, since the four metals of iron, aluminum, copper and magnesium have higher influence on the life of the last cast-forming carrier than other metals, the content of each of the four metals of iron, aluminum, copper and magnesium or the total content of the metal. The amount of iron is also one of the factors determining the grade. Therefore, in addition to the main factor of determining the predetermined grade by the total metal content, the content of iron, aluminum, copper and magnesium can be given different weights. Define the auxiliary factors for the predetermined level, For example, the weight of iron is the highest, the weight of aluminum is second, and so on. In this embodiment, the background value of step S102 is subtracted from the metal content detected in step S104 to determine the grade of the tantalum material.

In order to reuse the remaining second acid solution, the steps shown in Figure 2 are further performed:

In step S201, another raw material is supplied, and the other raw material is washed to wash away impurities on the surface of the other raw material. The cleaning step is the same as step S101, and is not described herein.

Step S202, immersing the other bismuth raw material in the remaining second acid solution (ie, the second acid solution in which the surface layer of the bismuth raw material is dissolved in step S103), so that the surface layer of the other bismuth raw material is dissolved in the second acid solution. Thereafter, the remaining portion of the other raw material that has not been dissolved is taken out from the second acid liquid; the other raw material taken out is placed in the deionized water and washed in an overflow manner for casting into a crystal crucible. use.

Step S203, taking a portion of the second acid solution in which the surface layer of the other tantalum material is dissolved in step S202, and detecting the metal content in the second acid solution taken by the inductively coupled plasma emission spectrometer, the detected metal component The same as step S102.

Step S204, the metal content of the second acid liquid measured before immersing the other raw material is a new background value (ie, the metal content measured in step S104), and deducting the new one according to the metal content detected in S203. The background value is used to determine the rank of the other raw material as one of the predetermined ranks in step S105.

If there are other niobium materials, the steps S201 to S204 are repeated to determine the grades of the other niobium materials.

Hereinafter, please refer to Table 1 and FIG. 3 to FIG. 5 to illustrate the use of the test method for the quality of the raw materials of the present embodiment to select three different grades (first to third) of tantalum raw materials according to the predetermined grade classifications, and The average carrier life of each of the grades of tantalum raw materials was determined by directional solidification method, wherein the total metal content, iron content, aluminum content, copper content, and magnesium content were all after subtracting the background value. Among them, although the total metal content of the third-stage niobium raw material is smaller than that of the second grade, the third-stage niobium raw material has a large iron content and a higher weight due to the iron content, and thus is judged to be the third grade.

The first-stage bismuth raw material has the lowest total metal content detected. It can be clearly seen from Fig. 3 that the red zone of the top of the first-stage bismuth raw material has the smallest red zone and the average carrier lifetime of the strontium. The highest, that is, the highest quality of the crystal. Please cooperate with Figure 4 and Figure 5. The total metal content and magnesium content of the second-grade tantalum raw material are higher than that of the third-grade tantalum raw material, but the iron content of the second-grade tantalum raw material is less than that of the third-grade tantalum raw material. The average carrier lifetime of the second stage of the germanium raw material is higher than the average carrier lifetime of the third stage of the germanium raw material, and the second stage The red zone of the top of the crucible of the crucible material is also smaller than the red zone of the top of the crucible of the third grade.

From the above, it can be seen that the grade of the raw material determined by the method for testing the quality of the raw material of the present invention can surely correspond to the quality of the crystal, and the present invention can be compared with the method of pushing the quality of the raw material with the quality of the wafer. Effectively reduce the time to judge the quality of raw materials. In addition, since the present invention only partially dissolves the ruthenium raw material (only dissolves the surface layer), the time of immersion in the acid solution is short, and the time for waiting for the dissolution of the ruthenium raw material can be reduced, and the productivity of the test can be increased. The inductively coupled plasma emission spectrometer can be used to quickly and accurately determine the quality of the raw materials. What's more worth mentioning is that after the grading and screening of the raw materials, the same grade of bismuth raw materials are cast into crystal enamel, which can ensure the casting of high-quality enamel, avoid mixing different grades of bismuth raw materials, and make the metal content more Many raw materials affect the quality of the wafer.

The above is only a preferred embodiment of the present invention, and equivalent changes to the scope of the present invention and the scope of the patent application are intended to be included in the scope of the present invention.

Claims (8)

The invention relates to a method for testing the quality of a raw material, comprising the following steps: A. providing a raw material; B. immersing the raw material in the acid liquid, so that the surface layer of the raw material is dissolved in the acid liquid, and the raw material is not The remaining part of the solution is taken out from the acid solution; C. Take a portion of the acid solution in the surface layer in which the bismuth raw material is dissolved in step B, and detect the metal content in the acid solution taken; and D, according to the test in step C The metal content determines that the grade of the tantalum material is one of a plurality of predetermined levels. The method for testing the quality of the raw material as described in claim 1, wherein the step A comprises washing the raw material. The method for testing the quality of the raw material according to claim 1, wherein the step B comprises detecting the metal content in the acid solution to obtain a background value; and the step D is deducting the background value according to the detected metal content to determine The grade of the raw material. The method for testing the quality of the raw material as described in claim 3, wherein the step D comprises the following steps: E. providing another raw material; F, immersing the other raw material in the surface layer of the raw material in the step B In the acid solution, after dissolving the surface layer of the other raw material in the acid solution, the remaining portion of the other raw material is not taken out from the acid solution; G, the step F is dissolved in the other raw material. a portion of the acid layer of the surface layer, and detecting the metal content in the acid solution taken; H, according to the metal content detected in step G minus the metal content detected in step C, to determine the grade of the other raw material is One of the predetermined levels in step D. The method for inspecting the quality of the raw material according to claim 1, wherein the metal component among the metal contents detected in the step C includes at least one of iron, aluminum, copper, and magnesium. The method for testing the quality of the raw material according to claim 1, wherein the acid solution in the step B comprises hydrofluoric acid and nitric acid. The method for testing the quality of the raw material as described in claim 1, wherein the bismuth raw material is immersed in the acid liquid in the step B for at least 5 minutes. The method for inspecting the quality of the raw material as described in claim 1, wherein in step C, the metal content is detected by an inductively coupled plasma emission spectrometer.