Method and device for collecting substances on surface of wafer

Abstract

The invention provides a method and device for collecting substances on the surface of a wafer, and the method comprises the steps: enabling the wafer to be inverted, and enabling the surface of the wafer to face downwards; a scanning device is arranged below the wafer, the top end of the scanning device carries scanning liquid, and the surface of the wafer is in contact with the scanning liquid; the wafer and the scanning device move relatively, and the scanning device scans at least part of the surface of the wafer, so that the scanning liquid dissolves substances on the surface of the wafer and collects the substances into the scanning liquid. According to the method, the step of atomizing or vaporizing the HF etching wafer surface is omitted, and the collection difficulty and cost are reduced; the wafer is inverted, so that particle pollution caused by the fact that particles on a fan filter unit (FFU) fall onto the surface of the wafer is avoided; meanwhile, the method is not only suitable for the hydrophilic wafer surface, but also suitable for the hydrophobic wafer surface, and has the advantages of being wide in application range and high in scanning and collecting accuracy.

Description

Technical Field

[0001] The invention belongs to the field of semiconductor manufacturing, and in particular relates to a method and a device for collecting wafer surface materials. Background Art

[0002] With the rapid development of the semiconductor manufacturing industry, the requirements for the preparation process of semiconductor devices are becoming increasingly higher. However, in the production process of semiconductor devices, there may be contaminants on the surface of the wafer of the semiconductor device formed through several processes, such as metal particle impurities or organic impurities. Specific contaminants may cause different defects in semiconductor devices.

[0003] For the metal particle impurities on the surface of the wafer, the existing technology uses the wafer surface vapor phase decomposition technology (VPD) for treatment. This technology first introduces HF gas (hydrofluoric acid gas) into the processing chamber to etch the wafer containing different types of films (such as bare film, oxide film or SiN film (silicon nitride film), etc.) to form a hydrophobic surface, and then uses an acidic solution to recover the trace metal particle impurities on the wafer surface. However, the above technology has the following shortcomings: on the one hand, after different types of wafers are etched with HF gas, the hydrophobic properties of the wafer surface are different, or tiny Si-containing particles are attached to the wafer surface, which causes repeated scanning failures when the negative pressure nozzle scans the wafer surface; on the other hand, after HF gas etches the wafer containing the SiN film, the silicon matrix composition in the recovered acidic solution will be complex. When the recovered acidic solution is subjected to ICPMS testing, the ICPMS signal will be suppressed or a false positive result will occur; at the same time, the particles in the processing chamber of the machine are easy to fall on the wafer surface to cause particle contamination, thereby reducing the production yield of semiconductor devices. Summary of the invention

[0004] The purpose of the present invention is to provide a method and device for collecting wafer surface materials, so as to solve the defects existing in the prior art when collecting wafer surface materials, thereby achieving the purpose of reducing the difficulty of collection, saving costs and expanding the scope of application.

[0005] To achieve the above-mentioned purpose, the present invention provides a method for collecting substances on the surface of a wafer, which comprises: inverting the wafer so that the surface of the wafer faces downward; arranging a scanning device under the wafer, the top of the scanning device carries a scanning liquid, and the surface of the wafer contacts the scanning liquid; the wafer and the scanning device move relative to each other, and the scanning device scans at least a portion of the surface of the wafer, so that the scanning liquid dissolves the substances on the surface of the wafer and collects them in the scanning liquid.

[0006] Preferably, a scanning head is provided on the top of the scanning device; a groove is provided on the top of the scanning head, and the groove is used to accommodate the scanning liquid.

[0007] Preferably, the liquid level of the scanning liquid is greater than the depth of the groove, so that the top of the scanning liquid protrudes out of the groove.

[0008] Preferably, the volume range of the groove is 0.2 mL to 1 mL.

[0009] Preferably, the wafer is sucked by a wafer suction cup and turned upside down.

[0010] Preferably, when collecting materials on the surface of the wafer, the wafer rotates; and / or the scanning device performs a number of straight-line reciprocating motions from the center of the wafer to the edge of the wafer.

[0011] Preferably, the rotation speed of the wafer is less than 10 rad / min, and the movement speed of the scanning device is less than 10 cm / min.

[0012] Optionally, the wafer surface is a hydrophilic surface or a hydrophobic surface.

[0013] Optionally, the wafer surface includes one or more of a Si film, a SiN film, a SiO2 film, and a SiON film.

[0014] Optionally, the substance on the surface of the wafer includes metal ions.

[0015] Preferably, the scanning liquid is an acidic solution or a mixture of an acidic solution and hydrogen peroxide.

[0016] Preferably, the acidic solution is a dilute HNO3 solution or a dilute HF solution.

[0017] Preferably, the concentration of the acidic solution is in the range of 2%-10%.

[0018] Preferably, in the mixture of the acidic solution and hydrogen peroxide, the concentration of the hydrogen peroxide is in the range of 3%-12%.

[0019] Optionally, the substance on the surface of the wafer includes organic matter.

[0020] Preferably, the scanning liquid is an organic solvent.

[0021] Preferably, the acidic solution or the mixture of the acidic solution and hydrogen peroxide is collected for ICPMS testing.

[0022] Preferably, the organic solvent is collected for GCMS testing.

[0023] Optionally, it can be implemented using a VPD machine.

[0024] The present invention also provides a device for collecting materials on the surface of a wafer, which includes: a wafer holding device, used to invert the wafer so that the wafer surface faces downward; a scanning device, arranged below the wafer holding device, and having a scanning liquid contained on the top; a control device, respectively connected to the wafer holding device and the scanning device, and configured to execute any of the methods for collecting materials on the surface of a wafer as described above.

[0025] Preferably, a scanning head is provided on the top of the scanning device, and a groove is provided on the top of the scanning head for accommodating the scanning liquid.

[0026] Optionally, the wafer holding device is a wafer suction cup, and a vacuum chamber is provided at the end of the wafer suction cup for adsorbing the wafer and inverting the wafer.

[0027] Preferably, the device for collecting materials on the surface of the wafer further comprises a manipulator device, and the manipulator device is connected to the wafer suction cup and is used for flipping, moving and rotating the wafer.

[0028] Preferably, a driving mechanism is connected to the bottom end of the scanning head, which can drive the scanning head to move relative to the wafer surface.

[0029] Preferably, the scanning head is made of PFA material or hydrophobic material.

[0030] Optionally, the hydrophobic material includes PTFE material.

[0031] In summary, compared with the prior art, the method and device for collecting wafer surface substances provided by the present invention have the following beneficial effects: by directly contacting the scanning liquid set on the scanning head with the wafer surface, the scanning liquid directly dissolves and collects the substances on the wafer surface, which omits the step of atomizing or vaporizing HF to etch the wafer surface, thereby reducing the difficulty and cost of collection; further, by inverting the wafer so that the wafer surface faces downward, particle contamination caused by particles on the fan filter unit (FFU) falling onto the wafer surface is avoided; at the same time, the method and device are not only applicable to hydrophilic wafer surfaces, but also to hydrophobic wafer surfaces, and have the advantages of a wide range of applications and high scanning and collection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic structural diagram of the device for collecting materials on the surface of a wafer according to the present invention. DETAILED DESCRIPTION

[0033] The following will be combined with the attached embodiment of the present invention Figure 1 , the technical solutions, structural features, objectives achieved and effects in the embodiments of the present invention are described in detail.

[0034] It should be noted that the drawings are in a very simplified form and use non-precise proportions. They are only used to conveniently and clearly assist in explaining the embodiments of the present invention, and are not used to limit the conditions for the implementation of the present invention. Therefore, they have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of size, without affecting the effects and purposes that can be achieved by the present invention, should still fall within the scope of the technical content disclosed by the present invention.

[0035] It should be noted that, in the present invention, the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or equipment including a series of elements includes not only the elements explicitly listed, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment.

[0036] Since semiconductor devices may have impurity particles on their wafer surfaces after being processed through a process, in order to analyze the physical and chemical properties of the impurity particles, the present invention provides a method for collecting materials on the wafer surface. The method can be implemented using a VPD machine, wherein the wafer is inverted so that the wafer surface faces downward; a scanning device is disposed under the wafer, and a scanning liquid is carried on the top of the scanning device, and the wafer surface is contacted with the scanning liquid; the wafer or the scanning device is moved so that the wafer and the scanning device move relative to each other, and the scanning device scans at least a portion of the surface of the wafer, so that the scanning liquid dissolves the materials on the wafer surface and collects them in the scanning liquid. The method omits the step of etching the wafer surface with atomized or vaporized HF, so that the collection method provided by the present invention is applicable to various types of wafer surfaces (such as hydrophilic surfaces or hydrophobic surfaces), while also reducing the difficulty and cost of collection; further reducing the influence of Si-containing substances generated on the wafer surface after HF gas etching on subsequent tests, and improving the accuracy of scanning liquid analysis; and at the same time, by inverting the wafer so that the wafer surface faces downward, particle contamination caused by particles on the fan filter unit (FFU) falling onto the wafer surface is avoided.

[0037] Please refer to Figure 1, which shows a schematic structural diagram of a device for collecting wafer surface substances provided by an exemplary embodiment of the present invention, the collecting device includes: a wafer holding device 100, used to invert the wafer 200 so that the wafer surface faces downward; a scanning device 300, which is arranged below the wafer holding device 100, and a scanning head 301 is provided on the top thereof, and a groove 302 is provided on the top of the scanning head 301, and a scanning liquid 303 is carried in the groove 302. The collecting device also includes a control device (not shown in the figure), which is respectively connected to the wafer holding device 100 and the scanning device 300, and is configured to execute the method for collecting wafer surface substances provided by the present invention. Based on the collecting device provided in this embodiment, the method for collecting wafer surface substances proposed in the present invention is further described in detail.

[0038] In this embodiment, a wafer suction cup is used as the wafer holding device 100, and a vacuum chamber is provided at one end of the wafer suction cup, and a robot device is connected to the other end. Figure 1 As shown, first, the vacuum chamber of the wafer suction cup is adsorbed on the bottom surface of the wafer, and the movement of the manipulator device drives the wafer suction cup to move and take the wafer 200 out of the disc; the control device sends a flip command to the wafer suction cup to control the wafer suction cup to flip the wafer 200 upside down so that the wafer surface faces downward. In other embodiments, the wafer holding device 100 can be a clamping component, and the wafer 200 is taken out of the disc by the clamping claws at the end of the clamping component, and the wafer 200 is turned upside down so that the wafer surface faces downward; or the wafer holding device 100 can also be a supporting component, and the wafer 200 is taken out of the disc by the manipulator device and flipped, so that the wafer surface is placed on the supporting component with the surface facing downward. By setting the wafer surface downward, the secondary contamination caused by the contaminated particles of the FFU falling onto the wafer surface when collecting the wafer surface material is avoided.

[0039] The wafer is, for example, an 8-inch or 12-inch polished silicon wafer. The wafer surface is a hydrophilic surface or a hydrophobic surface. The wafer surface includes one or more of a Si film, a SiN film, a SiO2 film, and a SiON film. Each film layer on the wafer surface is formed by thermal oxidation or a chemical vapor deposition process or a physical vapor deposition process.

[0040] Next, the scanning liquid 303 in the groove 302 at the top of the scanning head 301 is brought into contact with the surface of the wafer. The liquid level of the scanning liquid 303 is greater than the depth of the groove 302, so that the top of the scanning liquid 303 protrudes out of the groove 302. With this arrangement, while ensuring that the scanning liquid 303 is in contact with the wafer surface, the hard contact between the wafer surface and the scanning head 301 can be effectively avoided, reducing the damage to the wafer surface caused by contact friction. Preferably, the volume range of the groove 302 is 0.2mL to 1mL. The scanning head is made of PFA (soluble polytetrafluoroethylene) material or hydrophobic material, and the hydrophobic material includes PTFE (polytetrafluoroethylene) material. Due to the hydrophobicity of PTFE material, the scanning liquid will not remain in the groove, effectively avoiding cross contamination of the scanning liquid.

[0041] Further, when the scanning liquid 303 contacts the surface of the wafer, the control device controls the movement of the wafer 200 and / or the scanning device 300 respectively, so that the wafer 200 and the scanning device 300 move relative to each other, and the scanning liquid 303 scans the surface of the wafer, thereby dissolving the substances on the surface of the wafer and collecting them in the scanning liquid 303. Specifically, the bottom end of the scanning head 302 is connected with a driving mechanism, which can drive the scanning head 302 to move relative to the surface of the wafer. In some embodiments, the wafer 200 remains in a stationary state, and the driving mechanism drives the scanning head 302 to move circumferentially or radially along the surface of the wafer, driving the scanning liquid 303 to move along the surface of the wafer to achieve the collection of the substances on the surface of the wafer; or the scanning device 300 is kept in a fixed state, the wafer 200 is moved or the wafer 200 rotates, so that the wafer 200 and the scanning device 300 move relative to each other, so that the scanning range of the scanning liquid 303 covers at least part of the surface of the wafer, thereby achieving the collection of the substances on the surface of the wafer. In order to make the moving range of the scanning liquid 303 cover the entire surface of the wafer 200, the wafer 200 rotates, and the scanning device 300 performs several straight-line reciprocating motions from the center of the wafer 200 to the edge of the wafer 200, so that the scanning device 300 scans the entire surface of the wafer 200. Preferably, the rotation speed of the wafer is less than 10 rad / min, and the movement speed of the scanning device is less than 10 cm / min, so as to ensure that the scanning range of the scanning liquid 303 covers the entire surface of the wafer 200.

[0042] When the substance on the surface of the wafer is a metal ion, the scanning liquid 303 is an acidic solution or a mixture of an acidic solution and hydrogen peroxide. When the scanning liquid 303 is an acidic solution, the concentration range of the acidic solution is 2%-10%; when the scanning liquid 303 is a mixture of an acidic solution and hydrogen peroxide, the concentration range of the acidic solution is 2%-10%, and the concentration range of the hydrogen peroxide is 3%-12%. The acidic solution is a dilute HNO3 solution or a dilute HF solution. In this embodiment, a 5% HNO3 solution is used as the scanning liquid 303. The 5% HNO3 solution can dissolve the metal ions on the surface of the wafer and will not react with silicon, thereby realizing the collection of metal ions on the surface of the wafer and reducing secondary contamination of the wafer. In another embodiment, a mixture of 5% HF solution and 10% hydrogen peroxide is used as the scanning liquid 303. Although the HF solution can react with silicon, due to the short contact time between the scanning liquid 303 and the wafer surface and the low reaction rate between the HF solution and silicon, the HF solution has a weak dissolving effect on the Si-containing film layer on the wafer surface. Therefore, the scanning liquid 303 can collect metal ions on the metal surface but will not collect a large amount of Si-containing substances, thereby reducing the interference of the silicon substrate and improving the accuracy of the data results.

[0043] Further, the acidic solution or the mixture of the acidic solution and hydrogen peroxide that has collected the metal ions on the surface of the wafer is taken out from the groove 302 of the scanning head using a pipette and stored in a sample bottle. In this embodiment, the collected acidic solution or the mixture of the acidic solution and hydrogen peroxide is subjected to ICPMS testing (inductively coupled plasma mass spectrometry testing), and the ICPMS liquid collection tube is inserted into the sample bottle for elemental quantitative analysis, and the metal ions are tested using ICPMS.

[0044] When the substance on the surface of the wafer is organic, the scanning liquid 303 is an organic solvent, such as methanol or isopropyl alcohol (IPA). The organic solvent is dripped into the groove 302 of the scanning head 301, and the wafer 200 rotates with the wafer suction cup as the axis. The scanning device 300 can move linearly and uniformly from the center to the edge of the wafer 200, and the moving range of the organic solvent covers the entire surface of the wafer, so that the organic matter on the surface of the wafer is dissolved in the organic solvent. The organic solvent collected from the organic matter on the surface of the wafer is taken out from the groove 302 of the scanning head using a pipette and stored in a sample bottle. In this embodiment, the organic solvent is collected for GCMS testing (gas phase mass spectrometry testing), and the sampling system of GCMS takes samples from the sample bottle and performs component analysis to complete the test process of detecting organic matter using GCMS.

[0045] In summary, compared with the prior art, the method and device for collecting wafer surface materials provided by the present invention directly dissolve and collect materials on the wafer surface by bringing the scanning liquid set on the scanning head into direct contact with the wafer surface, thereby omitting the step of etching the wafer surface with atomized or vaporized HF, thereby reducing the difficulty and cost of collection; further, by inverting the wafer so that the wafer surface faces downward, particle contamination caused by particles on the fan filter unit (FFU) falling onto the wafer surface is avoided; at the same time, the method and device are not only applicable to hydrophilic wafer surfaces, but also to hydrophobic wafer surfaces, and have the advantages of a wide range of applications and high scanning and collection accuracy.

[0046] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. A method for collecting materials on the surface of a wafer, characterized in that: include: Turn the wafer upside down so that the wafer surface faces downward; A scanning device is arranged below the wafer, a scanning liquid is carried on the top of the scanning device, and the surface of the wafer is in contact with the scanning liquid; The wafer and the scanning device move relatively to each other, and the scanning device scans at least a portion of the surface of the wafer, so that the scanning liquid dissolves the substances on the surface of the wafer and collects them in the scanning liquid.

2. The method for collecting wafer surface material as claimed in claim 1, characterized in that: A scanning head is arranged on the top of the scanning device; a groove is arranged on the top of the scanning head, and the groove is used to contain the scanning liquid.

3. The method for collecting wafer surface material as claimed in claim 2, characterized in that: The liquid level of the scanning liquid is greater than the depth of the groove, so that the top of the scanning liquid protrudes out of the groove.

4. The method for collecting wafer surface material as claimed in claim 3, characterized in that: The volume range of the groove is 0.2 mL to 1 mL.

5. The method for collecting wafer surface material as claimed in claim 1, characterized in that: The wafer is sucked by the wafer chuck and turned upside down.

6. The method for collecting wafer surface material as claimed in claim 1, characterized in that: When collecting materials on the surface of the wafer, the wafer rotates; and / or the scanning device performs a number of straight-line reciprocating motions from the center of the wafer to the edge of the wafer.

7. The method for collecting wafer surface material as claimed in claim 6, characterized in that: The rotation speed of the wafer is less than 10 rad / min, and the movement speed of the scanning device is less than 10 cm / min.

8. The method for collecting wafer surface material as claimed in claim 1, characterized in that: The wafer surface is a hydrophilic surface or a hydrophobic surface.

9. The method for collecting wafer surface material as claimed in claim 1, characterized in that: The wafer surface includes one or more of a Si film, a SiN film, a SiO2 film, and a SiON film.

10. The method for collecting wafer surface material as claimed in claim 1, characterized in that: The substances on the surface of the wafer include metal ions.

11. The method for collecting wafer surface material according to claim 10, characterized in that: The scanning liquid is an acidic solution or a mixture of an acidic solution and hydrogen peroxide.

12. The method for collecting wafer surface material according to claim 11, characterized in that: The acidic solution is a dilute HNO3 solution or a dilute HF solution.

13. The method for collecting wafer surface material according to claim 11, characterized in that: The concentration of the acidic solution ranges from 2% to 10%.

14. The method for collecting wafer surface material according to claim 11, characterized in that: In the mixed solution of the acidic solution and hydrogen peroxide, the concentration of the hydrogen peroxide is in the range of 3%-12%.

15. The method for collecting wafer surface material as claimed in claim 1, characterized in that: The substances on the surface of the wafer include organic substances.

16. The method for collecting wafer surface material as claimed in claim 15, characterized in that: The scanning liquid is an organic solvent.

17. The method for collecting wafer surface material as claimed in claim 11, characterized in that: The acidic solution or the mixture of the acidic solution and hydrogen peroxide is collected for ICPMS testing.

18. The method for collecting wafer surface material as claimed in claim 16, characterized in that: The organic solvent was collected for GCMS analysis.

19. The method for collecting wafer surface material as claimed in claim 1, characterized in that: Implemented using VPD machine.

20. A device for collecting materials on the surface of a wafer, characterized in that: include: A wafer holding device, used to invert the wafer so that the wafer surface faces downward; A scanning device, arranged below the wafer holding device, with scanning liquid contained on the top thereof; The control device is connected to the wafer holding device and the scanning device respectively, and is configured to execute the method for collecting wafer surface material as described in any one of claims 1-19.

21. The device for collecting wafer surface material as claimed in claim 20, characterized in that: A scanning head is arranged on the top of the scanning device, and a groove is arranged on the top of the scanning head for accommodating the scanning liquid.

22. The device for collecting wafer surface material as claimed in claim 20, characterized in that: The wafer holding device is a wafer suction cup, and a vacuum chamber is arranged at the end of the wafer suction cup for adsorbing the wafer and turning the wafer upside down.

23. The device for collecting wafer surface material as claimed in claim 22, characterized in that: It also includes a robot device, which is connected to the wafer suction cup and is used for flipping, moving and rotating the wafer.

24. The device for collecting wafer surface material as claimed in claim 21, characterized in that: The bottom end of the scanning head is connected with a driving mechanism, which can drive the scanning head to move relative to the wafer surface.

25. The device for collecting wafer surface material as claimed in claim 21, characterized in that: The scanning head is made of PFA material or hydrophobic material.

26. The device for collecting wafer surface material as claimed in claim 25, characterized in that: The hydrophobic material includes PTFE material.

Images