Method for testing metal on surface of substrate

Abstract

The invention provides a substrate surface metal testing method, and belongs to the field of semiconductors. The substrate surface metal testing method comprises the following steps: providing a substrate to be detected, wherein the surface of the substrate is provided with an oxide layer; removing an oxide layer on the surface of the substrate by adopting hydrogen fluoride steam; the substrate with the oxide layer removed is subjected to heating treatment at a set temperature and then cooled; after cooling treatment, metal on the surface of the base body is extracted through scanning liquid; and testing the extracted metal. The method comprises the following steps: providing a substrate to be detected, wherein the surface of the substrate is provided with an oxide layer; removing an oxide layer on the surface of the substrate by adopting hydrogen fluoride steam; the substrate with the oxide layer removed is subjected to heating treatment at a set temperature and then cooled; after cooling treatment, metal on the surface of the base body is extracted through scanning liquid; the extracted metal is tested, so that the detection steps can be reduced, the condition of pollution introduction is avoided, and the purpose of detecting various metals can be achieved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a method for testing metal on the surface of a substrate. Background Art

[0002] Monitoring of metal content on the silicon wafer surface is pervasive throughout every step of wafer processing and manufacturing, such as crystal pulling, tumbling, chamfering, wire cutting, etching, polishing, cleaning, and epitaxy. Each process controls the metal level on the silicon wafer surface within a certain range. In particular, some power devices, such as CIS devices, have extremely high requirements for the metal content on the silicon wafer surface. Since metal leakage is the primary cause of device failure, the metal level on the silicon wafer must be strictly controlled during processing. Low-temperature oxidation technology is typically used to create a thick oxide layer to seal the back surface, preventing subsequent high-temperature heat treatments, especially epitaxy, from diffusing doped elements to the wafer surface. In addition to requirements for uniformity and density, this back-sealed oxide layer also has requirements for the metal content within the oxide layer.

[0003] VPD-ICPMS is the mainstream method for analyzing metals on silicon wafer surfaces. The main difficulty in metal measurement is the influence of high-silicon matrix. The influence of high-silicon matrix on the test mainly manifests in the following two aspects: 1) Matrix effect. Ultra-high-silicon matrix causes matrix suppression effect on the target trace metal test, that is, mass discrimination, which often causes all the elements to be tested to have low results; 2) Mass spectrometry interference caused by high-silicon matrix often causes high test results, such as: 30 Si 18 O. 28 SiFH and 29 SiF affects 48Ti, 28 Si2H2 and 29 Si2 influence 58 Ni, 28 Si 16 O2 impact 60 You.

[0004] Chinese patent application publication number CN118731145A discloses a method for manually detecting the metal content within a thick oxide layer on a silicon wafer. This patent involves manually shaking the wafer, etching away the surface oxide layer with a hydrogen fluoride (HF) solution, then heating the silicon substrate with a hot plate. A second manual shake scan recovers the surface metal, and the recovered liquid is heated and evaporated to dryness. Finally, the recovered liquid is tested for Ti content. This manual method for detecting the metal content within a thick oxide layer on a silicon wafer has the following drawbacks:

[0005] (1): Manual shaking etching makes it difficult to control the direction of the scanning liquid movement, resulting in etching failure and uneven etching.

[0006] (2): Manually shaking the wafer to scan and recover metal from the silicon wafer makes it difficult to control the direction of the scanning liquid movement, which can easily cause scanning failure and cannot guarantee that the metal on the entire silicon wafer surface is collected.

[0007] (3): Manual shaking uses a large volume of solution (1-5 mL) to remove the oxide layer. The volume of the residual liquid is large, and it takes longer to heat and evaporate it.

[0008] (4): The recovery liquid was scanned by hand-cranking, and a second evaporation to remove silicon was performed before the test, which increased the process variables and amplified the measurement error.

[0009] (5): After the scanning liquid is evaporated, a large volume of 5-10 mL of solution is used to extract the sample. High dilution multiples will cause measurement errors.

[0010] (6): This method is prone to human contamination and has HF operation safety risks.

[0011] Therefore, how to control the influence of the silicon substrate in the measurement of ultra-fine trace metals on thick oxide silicon wafers, while reducing process contamination and achieving effective and accurate quantitative detection of multiple elements, is a problem that needs to be solved in the current metal measurement of thick oxide silicon wafers.

[0012] It should be noted that the information disclosed in the background technology section of the invention is only intended to deepen the understanding of the general background technology of the invention, and should not be regarded as an admission or any form of implication that the information constitutes prior art already known to those skilled in the art. Summary of the Invention

[0013] The purpose of the present invention is to provide a substrate surface metal testing method to solve the problem of how to accurately measure the metal on the surface of a silicon wafer.

[0014] In order to solve the above technical problems, the present invention provides a substrate surface metal testing method, comprising:

[0015] Providing a substrate to be inspected, wherein the substrate has an oxide layer on its surface;

[0016] Using hydrogen fluoride vapor to remove the oxide layer on the substrate surface;

[0017] The substrate after the oxide layer is removed is heated at a set temperature and then cooled;

[0018] After the cooling treatment, the metal on the substrate surface is extracted using a scanning fluid;

[0019] The extracted metals were tested.

[0020] Preferably, the thickness of the oxide layer is

[0021] Preferably, the reaction formula for removing the oxide layer on the surface of the substrate using hydrogen fluoride vapor is:

[0022] SiO2+HF=H2SiF6+H2O, the hydrogen fluoride vapor etching time is 15min-30min, and the temperature of the reaction chamber is 15±2℃.

[0023] Preferably, when hydrogen fluoride vapor is used to remove the oxide layer on the surface of the substrate, an inert gas is introduced, and the inert gas purge rate is 3-10 L / min.

[0024] Preferably, the substrate is heated at a temperature of 150-250° C., the heating time is 5-15 minutes, and the cooling time is 10-30 minutes.

[0025] Preferably, a heating plate and a plurality of gaskets are provided, wherein the plurality of gaskets are arranged on the surface of the heating plate, and the substrate from which the oxide layer is to be removed is subjected to a heating treatment at a set temperature, comprising:

[0026] The substrate after the oxide layer is removed is placed on the surface of a plurality of gaskets, and the substrate is heated by using a heating plate.

[0027] Preferably, the substrate includes silicon polycrystalline, silicon single crystal, silicon wafer, silicon epitaxial wafer, or amorphous silicon thin film.

[0028] Preferably, the scanning fluid comprises:

[0029] 150-200 μL of a mixture of hydrogen fluoride and hydrogen peroxide, wherein the mass fraction of hydrogen fluoride is 1-5%, and the mass fraction of hydrogen peroxide is 1-6%.

[0030] Preferably, a scanning system is provided, which includes a supporting assembly, a driving mechanism and a control mechanism, wherein the supporting assembly is used to support the substrate, the driving end of the driving mechanism is connected to a scanning head, and the scanning head is in contact with the scanning liquid, and the control mechanism is connected to the driving mechanism, and the rotation angle, radius and speed of the driving mechanism are set by the control mechanism, and the rotation angle, radius and speed of the scanning head are adjusted so that the scanning liquid passes over the entire surface of the substrate.

[0031] Preferably, testing of the extracted metals includes:

[0032] Recover the scanning liquid into a sample bottle, and dilute the recovered scanning liquid to a set volume to obtain a test sample;

[0033] The test samples were subjected to metal testing.

[0034] Compared with the prior art, the substrate surface metal testing method of the present invention has the following advantages:

[0035] The present invention provides a substrate to be detected, wherein the substrate has an oxide layer on its surface; uses hydrogen fluoride vapor to remove the oxide layer on the substrate surface; heats the substrate after the oxide layer is removed at a set temperature and then cools it; after the cooling treatment, uses a scanning liquid to extract metal on the substrate surface; and tests the extracted metal. This method can reduce the number of detection steps, avoid the introduction of contamination, and achieve the purpose of being able to detect multiple metals. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic diagram of the structure of a pre-processing machine in one embodiment;

[0037] Figure 2 Schematic diagram of a structure in which a substrate is placed in a cavity in one embodiment of the present invention;

[0038] Figure 3 This is a schematic structural diagram of placing a substrate on a gasket surface for heat treatment in one embodiment of the present invention;

[0039] Figure 4 is a schematic diagram of recovering the scanning liquid on the surface of a substrate in one embodiment of the present invention;

[0040] Figure 5 Schematic diagram of testing a sample in one embodiment of the present invention

[0041] Figure 6 This is a flow chart of a method for testing metal on a substrate surface in one embodiment of the present invention;

[0042] Figure 7 1 is a schematic diagram of the remaining silicon substrate after a silicon wafer is processed using the method provided by the present invention in one embodiment of the present invention;

[0043] Figure 8 This is a schematic diagram comparing the recovery effect of 50 ppt spiked in one embodiment of the present invention;

[0044] Figure 9 This is a schematic diagram comparing the recovery effect of 100 ppt spiked solution in one embodiment of the present invention;

[0045] Figure 10 1 is a schematic diagram of the detection limit of the method obtained after a silicon wafer is processed using the detection method provided by the present invention in one embodiment of the present invention;

[0046] In the figure,

[0047] 100- pre-processing machine; 101- film box transfer stage;

[0048] 110- chamber; 120- heating plate;

[0049] 130-gasket; 140-scanning system;

[0050] 200-silicon wafer; 300-PFA sample bottle;

[0051] 310-scanning head; 320-scanning fluid;

[0052] 400-Inspection machine. DETAILED DESCRIPTION

[0053] In order to make the objects, advantages and features of the present invention clearer, the substrate surface metal testing method proposed in the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. It should be understood that the drawings in the specification do not necessarily show the specific structure of the present invention in proportion, and the illustrative features used to illustrate certain principles of the present invention in the drawings in the specification may also adopt a slightly simplified drawing method. The specific design features of the present invention disclosed herein include, for example, specific dimensions, directions, positions and shapes, which will be determined in part by the specific application and use environment. In addition, in the embodiments described below, the same figure mark is sometimes used in common between different drawings to represent the same part or a part with the same function, and its repeated description is omitted. In this specification, similar numbers and letters are used to represent similar items. Therefore, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0054] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0055] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0056] The core idea of ​​the present invention is to provide a method for testing metal on the surface of a substrate, which can reduce the number of detection steps, avoid the introduction of contamination, and achieve the purpose of being able to detect a variety of metals.

[0057] In order to realize the above idea, the present invention provides a substrate surface metal testing method, Figures 1 to 10 A specific embodiment of a substrate surface metal testing method disclosed herein includes the following steps S1 to S5.

[0058] Step S1: providing a substrate to be inspected, wherein the substrate has an oxide layer on its surface.

[0059] Specifically, refer to Figures 1 to 3 、 Figure 6 As shown, the substrate to be detected can be silicon polycrystalline, silicon single crystal, silicon wafer, silicon epitaxial wafer, amorphous silicon film, etc. Any substrate whose surface metal needs to be detected can adopt the method provided by this embodiment. In this embodiment, for the convenience of explanation, silicon wafer 200 is preferably used as the substrate. An oxide layer is formed on the surface of silicon wafer 200. The thickness of the oxide layer is For greater than The oxide layer may also be referred to as a thick oxide layer in this field.

[0060] During the specific operation, the silicon wafer is placed in a clean room and placed on the wafer cassette transfer stage 101 of the pre-processing machine 100, waiting for the next step of processing. It should be noted that the silicon wafer is kept in a Class 100 or higher clean room environment during the processing process. The pre-processing work is completed in a fume hood. The fume hood requires a Class 10 dust-free environment, sufficient exhaust, and a negative pressure state. The exhaust removes the air, keeping the silicon wafer surface dry and reducing detection interference.

[0061] The equipment for processing silicon wafers further includes a chamber 110 , a robotic arm (not shown in the figure), a vacuum pen (not shown in the figure), a heating plate 120 , a gasket 130 on the surface of the heating plate 120 , and the like.

[0062] Step S2: using hydrogen fluoride vapor to remove the oxide layer on the surface of the substrate.

[0063] Specifically, refer to Figure 2 and Figure 6As shown, a robotic arm is used to transport the silicon wafer to the chamber 110. Hydrogen fluoride (HF) vapor is introduced into the chamber 110 to etch the oxide layer to remove the oxide layer. The pretreatment machine 100 is set to allow the HF vapor to be introduced for a time period of 15 minutes to 30 minutes, and the temperature of the chamber 110 is set to 15±2°C. That is, the HF vapor etches the oxide layer for a time period of 15 minutes, 20 minutes, 30 minutes, or any other time period between 15 minutes and 30 minutes. The temperature of the HF vapor during etching of the oxide layer is 15±2°C.

[0064] The reaction formula for HF to remove the oxide layer is:

[0065] SiO2+HF=H2SiF6+H2O.

[0066] After etching the oxide layer with HF vapor, an inert gas, such as nitrogen or helium, is introduced into the cavity 110 for purging to remove the reaction product water vapor. At the same time, the silicon base is purged away by the nitrogen. In this embodiment, nitrogen is preferably used as the inert gas. The purge rate of the nitrogen is 3-10 L / min. The silicon base is a silicon wafer including pure silicon, a silicon compound (e.g., an oxide layer), a passivation layer, etc.

[0067] It should be noted that, in this embodiment, the oxide layer may be etched repeatedly with HF vapor and purged with nitrogen gas to completely remove the oxide layer.

[0068] Step S3: heating the substrate from which the oxide layer has been removed at a set temperature and then cooling it down.

[0069] Specifically, refer to Figure 1 、 Figure 3 and Figure 6 As shown, the silicon wafer 200 in the chamber 110 is removed using a vacuum pick and placed on the gasket 130 on the heating plate 120. The heating temperature of the heating plate 120 is 150-250°C, and the heating treatment time is 5-15 minutes, which is used to drive out the silicon. The principle of the drive-out silicon treatment is that H2SiF6 decomposes under heating conditions to produce SiF4 (SiF4 boiling point -86°C) and HF (HF boiling point 19.5°C), both of which evaporate in gaseous form.

[0070] The specific reaction formula is: H2SiF6=SiF4+HF.

[0071] Finally, the oxide layer metal remains on the surface of the silicon wafer. The HF steam etching method results in less water vapor residue on the surface of the silicon wafer, and a shorter heating time can achieve efficient silicon substrate removal effect, with a silicon removal efficiency of 99.52%. The surface of the heating plate 120 is a composite material of quartz and ceramic, which can meet higher temperature heating. There are 3 gaskets 130 on the surface of the heating plate 120, which are evenly distributed on the surface of the heating plate 120. The three gaskets 130 are used to support the silicon wafer. The material of the gasket 130 is pure quartz. The silicon wafer is in contact with 3 high-purity quartz gaskets, and does not contact the entire heating plate 120, which reduces the risk of contamination introduction and makes the operation of taking and placing the wafer more convenient.

[0072] Then turn off the heating plate to cool the silicon wafer. The cooling time is 10-30 minutes.

[0073] Step S4: After the cooling treatment, a scanning liquid is used to extract the metal on the surface of the substrate.

[0074] Specifically, refer to Figure 1 、 Figure 4 and Figure 6As shown, after the cooling process, a vacuum pen is used to suck the back side of the silicon wafer 200 (i.e., the side without silicon oxide). The silicon wafer 200 is then returned to the pre-processing machine 100 and placed in a scanning system 140 (i.e., VPD). The scanning system 140 includes a support assembly, a drive mechanism, and a control mechanism. The support assembly supports the substrate. The drive end of the drive mechanism is connected to a scanning head 310. The control mechanism is connected to the drive mechanism. The control mechanism sets the rotation angle, radius, and speed of the drive mechanism, adjusting the rotation angle and speed of the scanning head 310 so that the scanning liquid sweeps across the entire surface of the substrate. The drive mechanism can be a servo motor. The control mechanism can be a control panel, a controller, etc. The scanning head 310 can be steered at any angle under the control of the drive mechanism. Then, a scanning liquid 320 is dripped onto the surface of the silicon wafer 200 at a predetermined coordinate position. The scanning liquid 320 is a mixture of 150-200 μL of hydrogen fluoride and hydrogen peroxide, used to extract metal from the surface of the silicon wafer 200. The mass fraction of hydrogen fluoride is 1-5%, and the mass fraction of hydrogen peroxide is 1-6%. By setting the rotation angle, radius, and speed of the drive mechanism of the scanning system 140, the direction and movement speed of the scanning liquid 320 can be set, ensuring that the scanning liquid 320 passes completely across the surface of the silicon wafer 200. This can avoid manual vibrating etching, which makes it difficult to control the movement direction of the scanning liquid 320, resulting in etching failure and uneven etching. It can also avoid manual vibrating scanning to recover metal from the silicon wafer, which makes it difficult to control the movement direction of the scanning liquid, easily resulting in scanning failure and inability to ensure that the metal on the entire silicon wafer surface is collected. Since the total volume of the scanning liquid 320 in this embodiment is 150-200 μL, where "μL" represents the volume unit "microliter", the scanning liquid 320 in this embodiment has a smaller volume than a mixture measured in milliliters. The smaller scanning liquid volume extraction can achieve a lower method detection limit, making the measurement of ultra-fine trace metal elements more accurate.

[0075] Step S5: Testing the extracted metals.

[0076] Specifically, refer to Figures 4 to 6 As shown, the test of the extracted metal includes: recovering the scanning liquid into a sample bottle, and diluting the recovered scanning liquid to a set volume to obtain a test sample. The test sample is subjected to a metal test. The sample with the extracted metal is transferred to a 2mL PFA sample bottle 300, and ultrapure water is added to dilute the sample to 1mL to obtain a scanning sample. The 1mL scanning sample is transferred to the ICPMS / MS detection machine 400 for metal testing. In this step, there is no need to heat and evaporate the scanning recovery liquid again for silicon-based treatment, which reduces the operating steps, reduces interference and error introduction, shortens the sampling process time, and improves the testing efficiency of the sample.

[0077] Ginseng Figure 7 As shown in FIG, the signal intensity of 29Si on the surface of the silicon wafer is measured to measure the effect of removing the silicon substrate on the surface of the silicon wafer. Figure 7 It can be seen that when the oxide layer thickness is After the silicon wafer is etched only with HF, the signal intensity value of 29Si is 763367. The thickness of the oxide layer is The silicon wafer is etched by HF vapor by this method, and after heating, the signal intensity value of 29Si is 3655. The silicon wafer without oxide layer is etched by HF only, and the signal intensity value of 29Si is 3477. Therefore, the thickness of the oxide layer is This method uses HF vapor etching on silicon wafers, and after heating, the result is close to that of silicon wafers without an oxide layer. The silicon substrate removal rate reaches 99.52%. The remaining silicon substrate level is consistent with that of bare silicon wafers, and subsequent scanning recovery liquid does not need to be heated and evaporated again to remove the silicon substrate.

[0078] The above test method was evaluated using the following steps:

[0079] Step 1: Select 6 pieces of oxide layer with thickness of The six wafers come from the same ingot and are adjacent to each other, having been processed on the same machine.

[0080] Step 2: Divide the six wafers into two groups (Group 1 and Group 2), each containing three wafers (wafer 1, wafer 2, and wafer 3). Select one wafer from each group and leave it unspiked, while the other two wafers are spiked. Group 1 wafers are spiked with 100 μL of the 500 ppt standard solution (corresponding to a theoretical spiked amount of 50 pg and a concentration of 50 ppt in 1 mL of solution). Group 2 wafers are spiked with 200 μL of the standard solution (corresponding to a theoretical spiked amount of 100 pg and a concentration of 100 ppt in 1 mL of solution). Distribute the 100 μL and 200 μL standard solutions evenly over the wafer surfaces. Allow the wafers to air dry after spiking.

[0081] Step 3: After the silicon wafer etching and heating treatment described in the reference technical solution, wafer 1 is scanned once, and the concentration result obtained is C0. Wafer 2 and wafer 3 are scanned three times in succession (i.e., Scan 1 / Scan 2 / Scan 3), and the three concentration results C1 / C2 / C3 are obtained.

[0082] Absolute spike recovery % = (C1-C0) / Ctheoretical*100% formula (1);

[0083] Relative spike recovery % = C1 / (C1+C2+C3)*100% formula (2).

[0084] Ginseng Figure 8 and Figure 9As shown, Figure 8 3 is a schematic diagram comparing the recovery effect of 50 ppt spiked in one embodiment of the present invention. Figure 9 This figure compares the recovery performance of a 100 ppt spike solution in one embodiment of the present invention. The absolute recoveries of Scan 1 for 50 and 100 ppt spike solutions ranged from 77% to 114% for all 20 elements, demonstrating that the sample preparation and testing process are stable and effective, capable of fully recovering all metals from the silicon wafer surface without introducing significant contamination. The relative recoveries of Scan 1 for 50 and 100 ppt spike solutions approached 90% to 100% for all 20 elements, demonstrating the effectiveness and reliability of this method's single-scan testing results.

[0085] Ginseng Figure 10 As shown, Figure 10 This is a schematic diagram of the method detection limit (MDL) obtained after using the detection method provided by the present invention on silicon wafers in one embodiment of the present invention. Eleven surface-clean silicon wafers were subjected to the technical process, and three times the standard deviation of the results was the method detection limit (MDL). This method can achieve an extremely low method detection limit of 2E5 atoms / cm for 20 metal elements. 2 -3E7 atoms / cm 2 .

[0086] It can be seen from the above data that the substrate surface metal testing method provided in this embodiment can reduce the number of testing steps, avoid the introduction of contamination, and achieve the purpose of detecting a variety of metals.

[0087] In summary, the above embodiments provide a detailed description of different configurations of the substrate surface metal testing method. Of course, the above description is only a description of the preferred embodiment of the present invention, and is not any limitation to the scope of the present invention. The present invention includes but is not limited to the configurations listed in the above implementation. Those skilled in the art can draw inferences based on the contents of the above embodiments. Any changes and modifications made by ordinary technicians in the field of the present invention based on the above disclosure are within the scope of protection of the claims.

Claims

1. A method for testing metal on a substrate surface, characterized in that: include: Providing a substrate to be inspected, wherein the substrate has an oxide layer on its surface; Using hydrogen fluoride vapor to remove the oxide layer on the substrate surface; The substrate after the oxide layer is removed is heated at a set temperature and then cooled; After the cooling treatment, the metal on the substrate surface is extracted using a scanning fluid; The extracted metals were tested.

2. The substrate surface metal testing method according to claim 1, characterized in that: The thickness of the oxide layer is 3. The substrate surface metal testing method according to claim 1, characterized in that: The reaction formula for removing the oxide layer on the substrate surface by using hydrogen fluoride vapor is: SiO2+HF=H2SiF6+H2O, the hydrogen fluoride vapor etching time is 15min-30min, and the temperature of the reaction chamber is 15±2℃.

4. The substrate surface metal testing method according to claim 1, characterized in that: When hydrogen fluoride vapor is used to remove the oxide layer on the surface of the substrate, an inert gas is introduced, and the inert gas purge rate is 3-10 L / min.

5. The substrate surface metal testing method according to claim 1, characterized in that: The substrate is heated at a temperature of 150-250° C. for 5-15 minutes, and cooled for 10-30 minutes.

6. The substrate surface metal testing method according to claim 5, characterized in that: A heating plate and a plurality of gaskets are provided, wherein the plurality of gaskets are arranged on the surface of the heating plate. The substrate from which the oxide layer is to be removed is subjected to a heating treatment at a set temperature, comprising: The substrate after the oxide layer is removed is placed on the surface of a plurality of gaskets, and the substrate is heated by using a heating plate.

7. The substrate surface metal testing method according to claim 1, characterized in that: The substrate includes silicon polycrystal, silicon single crystal, silicon wafer, silicon epitaxial wafer and amorphous silicon film.

8. The substrate surface metal testing method according to claim 1, characterized in that: The scanning fluid comprises: 150-200 μL of a mixture of hydrogen fluoride and hydrogen peroxide, wherein the mass fraction of hydrogen fluoride is 1-5%, and the mass fraction of hydrogen peroxide is 1-6%.

9. The substrate surface metal testing method according to claim 8, characterized in that: A scanning system is provided, comprising a support assembly, a drive mechanism, and a control mechanism. The support assembly is used to support the substrate. A scanning head is connected to a drive end of the drive mechanism, and the scanning head contacts the scanning liquid. The control mechanism is connected to the drive mechanism. The control mechanism is used to set the rotation angle, radius, and speed of the drive mechanism, and adjust the rotation angle, radius, and speed of the scanning head so that the scanning liquid sweeps over the entire surface of the substrate.

10. The substrate surface metal testing method according to claim 1, characterized in that: The tests for the extracted metals include: Recover the scanning liquid into a sample bottle, and dilute the recovered scanning liquid to a set volume to obtain a test sample; The test samples were subjected to metal testing.

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