CN112614789A - Control method for metal impurities on surface of silicon wafer - Google Patents
Control method for metal impurities on surface of silicon wafer Download PDFInfo
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- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 title claims abstract description 180
- 229910052710 silicon Inorganic materials 0.000 title claims abstract description 179
- 239000010703 silicon Substances 0.000 title claims abstract description 179
- 239000002184 metal Substances 0.000 title claims abstract description 53
- 238000000034 method Methods 0.000 title claims abstract description 46
- 239000012535 impurity Substances 0.000 title claims abstract description 29
- 229910021642 ultra pure water Inorganic materials 0.000 claims abstract description 92
- 239000012498 ultrapure water Substances 0.000 claims abstract description 92
- 229910021645 metal ion Inorganic materials 0.000 claims abstract description 73
- 238000005507 spraying Methods 0.000 claims abstract description 25
- 238000001035 drying Methods 0.000 claims abstract description 24
- 238000009736 wetting Methods 0.000 claims abstract description 23
- 239000002253 acid Substances 0.000 claims abstract description 12
- 238000001095 inductively coupled plasma mass spectrometry Methods 0.000 claims abstract description 11
- 239000007788 liquid Substances 0.000 claims abstract description 5
- 238000004458 analytical method Methods 0.000 claims abstract description 4
- 239000000243 solution Substances 0.000 claims description 22
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- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims description 8
- 239000010409 thin film Substances 0.000 claims description 8
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- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 claims description 3
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 3
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- 238000010521 absorption reaction Methods 0.000 description 2
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- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
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- 230000007547 defect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000008595 infiltration Effects 0.000 description 1
- 238000001764 infiltration Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
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- 229920006395 saturated elastomer Polymers 0.000 description 1
- XJKVPKYVPCWHFO-UHFFFAOYSA-N silicon;hydrate Chemical compound O.[Si] XJKVPKYVPCWHFO-UHFFFAOYSA-N 0.000 description 1
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- H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
- H01L21/67005—Apparatus not specifically provided for elsewhere
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- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L22/00—Testing or measuring during manufacture or treatment; Reliability measurements, i.e. testing of parts without further processing to modify the parts as such; Structural arrangements therefor
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Abstract
The invention relates to a method for managing and controlling metal impurities on the surface of a silicon wafer, which comprises the following steps: providing a silicon wafer; wetting, namely spraying ultrapure water on the silicon wafer to fully wet the surface of the silicon wafer; drying the silicon wafer with the fully wet surface; repeating the steps of the wetting treatment and the drying treatment; carrying out acid solution treatment, and treating the surface of the silicon wafer by using an acid solution to obtain a treatment solution; performing analysis treatment, and analyzing the content of metal ions in the treatment liquid by using ICPMS; and a judging step, comparing the detected metal ion content with a metal pollution lower limit value, and judging whether the ultrapure water can continuously clean the silicon wafer. Therefore, the method can detect the pollution amount of the metal ions in the ultrapure water to the silicon wafer, can determine the relative influence of the metal ions in the ultrapure water on the increase or decrease of the metal content on the surface of the silicon wafer, and has the advantages of simple operation and high accuracy.
Description
Technical Field
The invention belongs to the field of semiconductor silicon chips, and particularly relates to a method for controlling metal impurities on the surface of a silicon chip.
Background
Silicon wafers are widely used as substrates for semiconductor devices. In a semiconductor device, metal contamination of a substrate degrades the performance of the device, and therefore a silicon wafer with less metal contamination is required.
In the related technology, the metal impurity content of the silicon wafer is mainly controlled by controlling the metal impurity content of the finally cleaned ultrapure water, and the metal ion content of the ultrapure water is mainly measured by an ICPMS (Inductively coupled plasma mass spectrometry) or AA atomic absorption spectrophotometer, but the detection method can only know the amount of the metal impurities in the ultrapure water, and cannot completely determine whether the metal ions can cause the metal content on the surface of the silicon wafer to increase or decrease. Therefore, it is important to develop a management and control method that can improve the above technical problems.
Disclosure of Invention
In order to solve the technical problem, the invention provides a method for managing and controlling metal impurities on the surface of a silicon wafer, which comprises the following steps: providing a silicon wafer; wetting, namely spraying ultrapure water on the silicon wafer to fully wet the surface of the silicon wafer; drying the silicon wafer with the fully wet surface; repeating the steps of the wetting treatment and the drying treatment; carrying out acid solution treatment, and treating the surface of the silicon wafer by using an acid solution to obtain a treatment solution; performing analysis treatment, and analyzing the content of metal ions in the treatment liquid by using ICPMS; and a judging step, comparing the detected metal ion content with a metal pollution lower limit value, and judging whether the ultrapure water can continuously clean the silicon wafer. Therefore, the method can detect the pollution amount of the metal ions in the ultrapure water to the silicon wafer, can determine the relative influence of the metal ions in the ultrapure water on the increase or decrease of the metal content on the surface of the silicon wafer, and has the advantages of simple operation, low price and easy availability of reagents. In addition, the method can be used for monitoring the long-term change trend of the metal ion content on the surface of the silicon wafer. The inventor finds that the number of the finally delivered silicon wafer with the overproof metal impurity content is obviously lower than that of the finally delivered silicon wafer with the overproof metal impurity content which is managed and controlled by the existing method.
The method can directly and accurately obtain the metal impurity content on the surface of the silicon wafer, and does not need to indirectly predict the metal impurity content on the surface of the silicon wafer through the metal impurity content of ultrapure water.
According to the embodiment of the invention, in the judging step, when the content of the detected at least one metal ion is greater than or equal to the lower limit value of metal pollution, the content of the metal ion in the ultrapure water can affect the performance of the silicon wafer, and the ultrapure water is stopped from being used for cleaning the silicon wafer; and when the detected contents of all metal ions are less than the metal pollution lower limit value, the ultrapure water can continuously clean the silicon wafer. Therefore, the method can directly judge whether the metal ions in the ultrapure water can influence the performance of the silicon wafer or not, can directly judge whether the ultrapure water can continuously clean the silicon wafer or not, and is simple and convenient to operate.
According to an embodiment of the present invention, the silicon wafer is a silicon wafer having a hydrophilic thin film. Therefore, the silicon wafer with the hydrophilic film has a hydrogen bond mutual attraction effect with water molecules, the water retaining capacity of the silicon wafer with the hydrophilic film is better, and compared with a hydrophobic silicon wafer, after drying treatment, the silicon wafer with the hydrophilic film can retain more metal ions on the surface of the silicon wafer, so that higher signal intensity of the metal ions can be obtained.
According to the embodiment of the invention, the silicon wafer with the hydrophilic film is obtained after being treated by chemicals; the chemical comprises NH4OH and H2O2Mixed solution of (2) and HCl/H2At least one of O solutions.
According to the embodiment of the present invention, the contact angle of the silicon wafer with the ultrapure water is 5 to 30 °. This makes it possible to retain more metal ions and further improve the accuracy of the detection result.
According to an embodiment of the present invention, the number of repetitions is not less than 3; for example, the number of repetitions is 3, 4, 5, 6 or more. By repeating the steps of the wetting process and the drying process, the accuracy of the measurement result can be improved.
Further, the number of repetitions is preferably 3 or 4. At the moment, the content of the metal ions retained on the surface of the silicon wafer reaches a saturation value, the steps of wetting treatment and drying treatment are continuously repeated, the measured content of the metal ions cannot be continuously increased, and the content of the metal ions retained on the surface of the silicon wafer can be more accurately detected.
According to the embodiment of the invention, in the wetting treatment, the spraying direction of the ultrapure water is vertical to the plane of the silicon wafer.
According to an embodiment of the invention, the wetting treatment comprises: and placing the silicon wafer in a wafer boat and in a horizontal spin dryer capable of spraying ultrapure water.
According to an embodiment of the invention, the wetting treatment comprises: and ultrapure water is sprayed above the center of the silicon wafer, the silicon wafer rotates, and the ultrapure water is thrown to an area outside the center through centrifugal force, so that the surface of the silicon wafer is completely covered with the ultrapure water.
Specifically, after the ultrapure water is sprayed on the surface of the silicon wafer, the metal ions in the ultrapure water can remain on the surface of the silicon wafer after the drying treatment.
According to an embodiment of the invention, the drying process comprises: and (3) spin-drying the ultrapure water on the surface of the silicon wafer by using a horizontal spin dryer.
The acid solution comprises a hydrofluoric acid solution.
According to an embodiment of the invention, the metal ion comprises Na+、K+、Ca2+At least one of (1).
Drawings
FIG. 1 is a flow chart of a method for controlling metal impurities on a silicon wafer surface according to the present invention.
FIG. 2 shows the detection of Na on the surface of a silicon wafer according to the present invention+Correlation graph of content and spraying times.
FIG. 3 shows the surface K of a silicon wafer measured by the present invention+Correlation graph of content and spraying times.
FIG. 4 shows the surface Ca of the silicon wafer measured by the present invention2+Correlation graph of content and spraying times.
Detailed Description
The following describes embodiments of the present invention in detail. The following examples are illustrative only and are not to be construed as limiting the invention. The examples, where specific techniques or conditions are not indicated, are to be construed according to the techniques or conditions described in the literature in the art or according to the product specifications. The reagents used are not indicated by manufacturers, and are all conventional products available on the market.
In the existing method, metal impurities on the surface of a silicon wafer are indirectly controlled by controlling the metal impurities of ultrapure water, the metal impurity content of the ultrapure water is used for indirectly predicting the metal impurity content of the surface of the silicon wafer, the metal impurities in the ultrapure water are mainly measured by an ICPMS or AA atomic absorption spectrophotometer, the metal impurity content of the surface of the silicon wafer can only be indirectly predicted by the metal impurity content of the ultrapure water in the existing detection method, and the influence of the metal ions in the ultrapure water on the metal ion content of the silicon wafer cannot be determined. Specifically, the existing detection method can only detect a fixed content of metal ions in the ultrapure water, but cannot determine the content of the metal ions in the ultrapure water retained on the surface of the silicon wafer after the surface of the silicon wafer is cleaned with the ultrapure water, that is, the existing detection method cannot determine the relative influence of the metal ions in the ultrapure water on the increase or decrease of the metal content on the surface of the silicon wafer.
In order to solve the above technical problem, the present invention provides a method for controlling metal impurities on a surface of a silicon wafer, as shown in fig. 1, the method includes the following steps:
s100, providing a silicon wafer
According to an embodiment of the present invention, the silicon wafer is a silicon wafer having a hydrophilic thin film. Further, the contact angle of the silicon wafer with ultrapure water is 5 to 30 °, for example, may be 5 °, 6 °, 7 °, 8 °, 9 °, 10 °, 11 °, 12 °, 13 °, 14 °, 15 °, 16 °, 17 °, 18 °, 19 °, 20 °, 21 °, 22 °, 23 °, 24 °, 25 °, 26 °, 27 °, 28 °, 29 °, 30 °. Therefore, the silicon wafer has hydrophilicity, and compared with a hydrophobic silicon wafer, the silicon wafer with the hydrophilic film can be enriched with more metal ions, so that the influence of the metal ions in the ultrapure water on the metal content of the surface of the silicon wafer can be more accurately detected.
Illustratively, the silicon wafer having a hydrophilic thin film may be a silicon wafer having a hydrophilic silicon oxide thin film. The silicon oxide and water have a hydrogen bond attraction effect, so that the silicon wafer with the hydrophilic film can retain water, metal ions in the water can be retained on the surface of the silicon wafer, and the measurement accuracy is further improved.
The silicon chip with the hydrophilic film is obtained after being treated by chemicals. Specifically, the chemical comprises NH4OH and H2O2Mixed solution of (2) and HCl/H2At least one of O solutions.
The silicon wafer with the hydrophilic film has already been subjected to a final cleaning step, such as RCA, SC1, SC2, and the like, that is, the surface of the silicon wafer with the hydrophilic film has no metal ions, and thus the performance of the silicon wafer is not affected.
S200, carrying out wetting treatment, namely spraying ultrapure water on the silicon wafer to fully wet the surface of the silicon wafer
According to the embodiment of the invention, in the wetting treatment, the spraying direction of the ultrapure water is vertical to the plane of the silicon wafer.
According to an embodiment of the present invention, the wetting treatment includes: and placing the silicon wafer in a wafer boat and in a horizontal spin dryer capable of spraying ultrapure water.
The surface of the silicon wafer is fully wetted, which means that each area on the silicon wafer is wetted by ultrapure water, and a water film is formed on the surface. Compared with partial infiltration, the method for fully wetting the surface of the silicon wafer to achieve full coverage can improve effective signals of measurement, and further improve the accuracy of measurement results.
For example, the center spray can be matched with the rotation mode, the ultrapure water at the center is thrown to the area outside the center by using the centrifugal force, and finally the full coverage of the surface of the silicon wafer is achieved. The method specifically comprises the following steps: and ultrapure water is sprayed above the center of the silicon wafer, the silicon wafer rotates, and the ultrapure water is thrown to an area outside the center through centrifugal force, so that the surface of the silicon wafer is completely covered with the ultrapure water.
S300, drying the silicon wafer with the fully wet surface
According to an embodiment of the invention, the drying process comprises: and (3) spin-drying the ultrapure water on the surface of the silicon wafer by using a horizontal spin dryer.
S400, repeating the steps of wetting treatment and drying treatment
The inventor finds that if the steps of wetting treatment and drying treatment are carried out only once, the metal ions retained on the surface of the silicon wafer cannot reach the saturation enrichment value, and the problem of inaccurate control method exists. If the steps of wetting treatment and drying treatment are repeated, the content of the metal ions retained on the surface of the silicon wafer can be increased along with the increase of the repetition times, and when the saturated enrichment value is reached, the repetition times are continuously increased, so that the content of the metal ions retained on the surface of the silicon wafer can not be continuously increased.
According to the embodiment of the present invention, the number of repetitions is not less than 3 times, and may be, for example, 3 times, 4 times, 5 times, 6 times, or more. Thus, the accuracy of the detection result can be further improved by repeating the steps of the wetting treatment and the drying treatment.
The inventor obtains through a plurality of experiments that when the repetition times are 3 times or 4 times, the metal ions enriched on the surface of the silicon wafer reach the saturation enrichment value of the silicon wafer. If the number of repetitions is increased further, the measured metal ion content does not increase further, but remains unchanged.
S500, performing acid solution treatment, and treating the surface of the silicon wafer with the acid solution to obtain a treatment solution
According to an embodiment of the present invention, the acid solution comprises a hydrofluoric acid solution. This makes it possible to contain metal ions in the obtained treatment liquid. The concentration of the acid solution is not limited in the present invention, and can be selected by those skilled in the art according to the use requirement.
S600, analyzing and processing, and analyzing the content of metal ions in the processing liquid by using ICPMS
According to an embodiment of the invention, the metal ion comprises Na+、K+、Ca2+At least one of (1).
It is to be understood that the parameters of ICPMS analysis are not particularly limited by the present invention and may be selected by one skilled in the art depending on the metal ion to be detected.
S700, a judging step, namely comparing the detected metal ion content with a metal pollution lower limit value, and judging whether the ultrapure water can continuously clean the silicon wafer
According to the embodiment of the invention, when the content of the detected at least one metal ion is greater than or equal to the lower limit value of metal pollution, the metal ion content in the ultrapure water can affect the performance of the silicon wafer, and the ultrapure water cannot be used for cleaning the silicon wafer continuously. When the detected contents of all metal ions are less than the lower limit value of metal pollution, the contents of the metal ions do not influence the performance of the silicon wafer, and the silicon wafer can be cleaned by using the ultrapure water. Wherein, the lower limit value of the metal pollution refers to the lowest value of the metal ion content which influences the performance of the silicon chip.
The existing method indirectly reflects the pollution amount of metal ions in the ultrapure water to a silicon wafer by measuring the content of the metal ions in the ultrapure water. The method can improve the problem, and the method can directly obtain the pollution amount of the metal ions in the ultrapure water to the silicon wafer.
The examples of the invention described below, unless otherwise indicated, all reagents used are commercially available or can be prepared by the methods described herein.
Note that, atom/cm2The conversion relationship with ppt is known to those skilled in the art. In particular for Na+For example, 100ppt is 3.71 × 109Atom/cm2. For K+For example, 100ppt ═ 2.18 × 109Atom/cm2. For Ca2+For example, 100ppt ═ 2.13 × 109Atom/cm2。
Example 1
The ultrapure water sample used in example 1 was ultrapure water after the silicon wafer was washed for a certain period of time, in which the metal ion content was unknown, and the method for controlling the metal impurities on the surface of the silicon wafer was as follows.
(1) A silicon wafer having a hydrophilic film is provided. The silicon wafer having a hydrophilic thin film is a silicon wafer having a hydrophilic silicon oxide thin film, and the silicon wafer having a hydrophilic thin film has been subjected to final cleaning (RCA, SC1, SC2 cleaning, etc. have been completed). The contact angle of the silicon wafer and the ultrapure water is 15 degrees.
(2) And spraying ultrapure water on the silicon wafer to fully wet the surface of the silicon wafer. And placing the silicon wafer in a wafer boat and a horizontal spin dryer capable of spraying ultrapure water. The ultrapure water at the center is thrown to the area outside the center by centrifugal force by using a center spraying and rotation mode, and finally the surface of the silicon wafer is completely covered with ultrapure water. The spraying direction of the ultrapure water is vertical to the plane of the silicon wafer during spraying.
(3) And drying the surface of the silicon wafer. And (4) spin-drying the ultrapure water on the surface of the silicon wafer by using a horizontal spin dryer.
(4) Repeating the steps (2) to (3) for 1 time. That is, the number of spraying in example 1 was 2.
(5) And treating the surface of the silicon wafer by using a hydrofluoric acid solution to obtain a treatment solution.
(6) The metal ion content in the treatment solution was analyzed by ICPMS.
The measurement results are: na on the surface of the silicon wafer, as shown in FIGS. 2 to 4+The content of (A) is 0.00198834X 1010Atom/cm2I.e. 0.54 ppt. K on the surface of a silicon wafer+The content of (A) is 0.00029X 1010Atom/cm2I.e. 0.133 ppt. Ca on the surface of silicon wafer2+The content of (A) is 0.00437199X 1010Atom/cm2I.e. 2.05 ppt.
The control method further comprises the following steps: (7) and comparing the detected metal ion content with a metal pollution lower limit value, and judging whether the ultrapure water can continuously clean the silicon wafer.
It should be noted that different substrates have different requirements for the metal impurity content on the silicon wafer surface, i.e., the lower limit of metal contamination varies according to the final product. Further, when the content of the detected at least one metal ion is greater than or equal to the lower limit value of metal pollution, the content of the metal ion in the ultrapure water influences the performance of the silicon wafer, and the ultrapure water cannot be used for cleaning the silicon wafer continuously. When the detected contents of all metal ions are less than the lower limit value of metal pollution, the contents of the metal ions do not influence the performance of the silicon wafer, and the silicon wafer can be cleaned by using the ultrapure water.
Example 2
The method of reference example 1 was used to measure the metal impurity content of the silicon wafer surface, and it was different from example 1 in that the number of repetitions in step (4) was 3. That is, the number of spraying in example 2 was 4.
The measurement results are: na on the surface of the silicon wafer, as shown in FIGS. 2 to 4+In an amount of 0.00641831x1010Atom/cm2I.e. 1.73 ppt. K on the surface of a silicon wafer+The content of (A) is 0.00126989X 1010Atom/cm2I.e. 0.58 ppt. Ca on the surface of silicon wafer2+The content of (A) is 0.0121022X 1010Atom/cm2I.e. 5.68 ppt.
Example 3
The method of reference example 1 was used to measure the metal impurity content of the silicon wafer surface, and it was different from example 1 in that the repetition of step (4) was 4 times. That is, the number of spraying in example 3 was 5.
Na measured on the surface of the silicon wafer as shown in FIGS. 2 to 4+、K+And Ca2+The content of metal ions was the same as that measured in example 2.
Example 4
The method of reference example 1 was used to measure the metal impurity content of the silicon wafer surface, and it was different from example 1 in that the repetition of step (4) was 5 times. That is, the number of spraying in example 4 was 6.
Na measured on the surface of the silicon wafer as shown in FIGS. 2 to 4+、K+And Ca2+The content of metal ions was the same as that measured in example 2.
Comparative example 1
The concentration by heating was used for improving the accuracy, and the content of metal ions in the ultrapure water sample in example 1 was measured by ICPMS (inductively coupled plasma mass spectrometry).
The measurement results are: na in ultrapure water+In an amount of<0.35ppt。K+In an amount of<0.43ppt。Ca2+In an amount of<0.39ppt。
Comparative example 2
The method of reference example 1 was used to measure the content of metal impurities on the surface of a silicon wafer, and it was different from example 1 in that step (4) was omitted, that is, step (5) was directly performed after step (3). That is, the number of times of repeating the steps of the wetting treatment and the drying treatment is 0, that is, the number of times of spraying is 1.
The measurement results are: na on the surface of the silicon wafer, as shown in FIGS. 2 to 4+The content of (A) is 0.0013X 1010Atom/cm2I.e. 0.35 ppt. K on the surface of a silicon wafer+The content of (A) is 0.00029X 1010Atom/cm2I.e. 0.133 ppt. Ca on the surface of silicon wafer2+The content of (A) is 0.0043X 1010Atom/cm2I.e. 2.02 ppt.
As can be seen from the results of measurement combining the examples and comparative examples, as shown in FIGS. 2 to 4, when the number of repetitions was 3, that is, when the number of spraying was 4, metal ions (Na) were concentrated on the surface of the silicon wafer+、K+And Ca2+) The content reaches saturation, the spraying times are continuously increased, and metal ions (Na) are enriched on the surface of the silicon chip+、K+And Ca2+) The content does not continue to increase but remains unchanged.
The method improves the defects of the existing detection method, and when the performance of the substrate is reduced, the method can judge whether the ultrapure water for cleaning the silicon wafer pollutes the silicon wafer, can directly judge whether the reason for reducing the performance of the substrate is caused by the ultrapure water for cleaning the silicon wafer, and can quickly search the reason for reducing the performance of the substrate.
And the method can determine the relative influence of the metal ions in the ultrapure water on the increase or decrease of the metal content on the surface of the silicon wafer.
The method can detect whether the content of metal ions in the ultrapure water for cleaning the silicon wafer influences the performance of the silicon wafer, namely whether the ultrapure water can continuously clean the silicon wafer. For example, when a silicon wafer is washed with ultrapure water for a certain period of time, the metal ion content in the ultrapure water is unknown. The method of the invention is used for detecting the ultrapure water after a period of time, can directly measure the metal ion content in the ultrapure water enriched on the surface of the silicon wafer, determine whether the ultrapure water can be continuously used for cleaning the silicon wafer, and determine whether the ultrapure water can influence the performance of the silicon wafer. When the content of the detected at least one metal ion is greater than or equal to the lower limit value of metal pollution, the content of the metal ion in the ultrapure water can affect the performance of the silicon wafer, and the ultrapure water cannot be used for cleaning the silicon wafer continuously.
In the description herein, references to the terms "one embodiment," "another embodiment," "yet another embodiment," "an example," "another example," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (10)
1. A method for managing and controlling metal impurities on the surface of a silicon wafer is characterized by comprising the following steps:
providing a silicon wafer;
wetting, namely spraying ultrapure water on the silicon wafer to fully wet the surface of the silicon wafer;
drying the silicon wafer with the fully wet surface;
repeating the steps of the wetting treatment and the drying treatment;
carrying out acid solution treatment, and treating the surface of the silicon wafer by using an acid solution to obtain a treatment solution;
performing analysis treatment, and analyzing the content of metal ions in the treatment liquid by using ICPMS;
and a judging step, comparing the detected metal ion content with a metal pollution lower limit value, and judging whether the ultrapure water can continuously clean the silicon wafer.
2. The management and control method according to claim 1, wherein in the judging step, when the detected content of at least one metal ion is greater than or equal to a metal pollution lower limit value, the silicon wafer is not cleaned by using ultrapure water;
and when the detected contents of all metal ions are less than the metal pollution lower limit value, the ultrapure water can continuously clean the silicon wafer.
3. The management and control method according to claim 1, wherein the silicon wafer is a silicon wafer with a hydrophilic thin film.
4. The management and control method according to claim 3, wherein the silicon wafer with the hydrophilic film is obtained after chemical treatment;
the chemical comprises NH4OH and H2O2Mixed solution of (2) and HCl/H2At least one of O solutions.
5. The method for managing and controlling according to claim 3, wherein the contact angle of the silicon wafer with the ultrapure water is 5-30 °.
6. The management and control method according to claim 1, wherein the number of repetitions is not less than 3;
optionally, the number of repetitions is 3 or 4.
7. The management and control method according to claim 1, wherein in the wetting treatment, the spraying direction of ultrapure water is perpendicular to the plane of the silicon wafer;
optionally, the wetting treatment comprises: and placing the silicon wafer in a wafer boat and in a horizontal spin dryer capable of spraying ultrapure water.
8. The management and control method according to claim 7, wherein the wetting treatment includes: and ultrapure water is sprayed above the center of the silicon wafer, the silicon wafer rotates, and the ultrapure water is thrown to an area outside the center through centrifugal force, so that the surface of the silicon wafer is completely covered with the ultrapure water.
9. The management and control method according to claim 1, wherein the drying process includes: spin-drying the ultrapure water on the surface of the silicon wafer by using a horizontal spin dryer;
optionally, the acid solution comprises a hydrofluoric acid solution.
10. The management and control method of claim 1, wherein the metal ions comprise Na+、K+、Ca2+At least one of (1).
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115793416A (en) * | 2023-01-16 | 2023-03-14 | 广州粤芯半导体技术有限公司 | Semiconductor device preparation method and method for monitoring chemical impurities in photoetching process |
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| JPH05251542A (en) * | 1992-03-04 | 1993-09-28 | Fujitsu Ltd | Monitoring method for purity of pure water |
| US20080121027A1 (en) * | 2006-06-29 | 2008-05-29 | Texas Instruments Incorporated | Method for measuring contamination in liquids at ppq levels |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05251542A (en) * | 1992-03-04 | 1993-09-28 | Fujitsu Ltd | Monitoring method for purity of pure water |
| US20080121027A1 (en) * | 2006-06-29 | 2008-05-29 | Texas Instruments Incorporated | Method for measuring contamination in liquids at ppq levels |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115793416A (en) * | 2023-01-16 | 2023-03-14 | 广州粤芯半导体技术有限公司 | Semiconductor device preparation method and method for monitoring chemical impurities in photoetching process |
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