Device and method for cleaning particles on surface of wafer

Abstract

The invention belongs to the technical field of semiconductor technologies, and discloses a device and method for cleaning particles on the surface of a wafer, the device comprises a first shell, a second shell and an adsorption cavity, the first shell and the second shell are symmetrically buckled to form a vacuum cleaning cavity, a cleaning assembly is arranged in the vacuum cleaning cavity, and the adsorption cavity is internally provided with an adsorption assembly. And the second shell is connected with the adsorption cavity. The method solves the problem that particles exist in grooves in the surface of a current semiconductor wafer and cannot be cleaned.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor process, and in particular, relates to a method and device for cleaning particles on the surface of a wafer. Background Art

[0002] In the semiconductor wet process, after the wafer is wet-etched or debonded with chemical liquid, the wafer surface is soaked and rinsed with pure water to clean it. However, due to the dirtiness of the tank or the influence of pure water particles, there are usually 0.3um-1um particles on the wafer surface. These particles will be adsorbed in the grooves on the wafer surface, and nitrogen purging cannot clean them up. Summary of the invention

[0003] The technical problem solved by the present invention is: to provide a method and device for cleaning particles on the surface of a wafer, thereby solving the problem that particles exist in grooves on the surface of a semiconductor wafer and cannot be cleaned.

[0004] The technical solution of the present invention is: the present invention provides a device for cleaning particles on the surface of a wafer, comprising: a first shell, a second shell and an adsorption chamber, the first shell and the second shell are symmetrically buckled to form a vacuum cleaning chamber, a cleaning component is provided in the vacuum cleaning chamber, and the second shell is connected to the adsorption chamber.

[0005] Furthermore, a side of the second shell close to the adsorption chamber is provided with an opening and communicated with the adsorption chamber, a vacuum pump is provided in the adsorption chamber, a vacuum tube is provided on the side wall of the adsorption chamber, and the vacuum pump is connected to the vacuum tube.

[0006] Furthermore, a wafer stage is provided on a side of the second shell close to the first shell, and the wafer stage includes a fixing pad and a positioning column, and the fixing pad and the positioning column are both arranged along the circumference of the second shell.

[0007] Furthermore, a sealing ring is provided on a side of the second shell close to the first shell. The sealing ring is arranged along the circumference of the second shell, and the diameter of the sealing ring is larger than the diameter of the wafer stage.

[0008] Furthermore, the cleaning assembly includes a brush head and a lifting shaft fixedly connected to the brush head, a plurality of tufted brushes are provided on the side of the brush head facing the first shell, and a plurality of adsorption holes are also provided on the brush head, and the adsorption holes penetrate the brush head in a direction parallel to the axis of the lifting shaft.

[0009] Furthermore, the device also includes a cabinet, the vacuum cleaning chamber is arranged in the cabinet, an axial flow fan is provided on one side of the cabinet, and an exhaust port is provided on the other side, and the axial flow fan and the exhaust port are symmetrically arranged along both sides of the vacuum cleaning chamber.

[0010] Furthermore, a first filter is provided on the side of the axial flow fan close to the vacuum cleaning chamber, a second filter is provided on the side of the axial flow fan away from the vacuum cleaning chamber, and a third filter is provided on the side of the exhaust port close to the vacuum cleaning chamber. The first filter, the second filter and the third filter are all arranged in parallel.

[0011] Furthermore, a lifting column is provided on a side of the first shell away from the second shell, a cylinder is provided on the top of the cabinet, and the lifting column is movably connected to the cylinder.

[0012] Furthermore, the first shell, the second shell and the positioning column are all made of ceramic, the sealing ring is made of rubber, and the fixing pad is made of silicone.

[0013] The present invention also provides a method for cleaning particles on a wafer surface, comprising:

[0014] Step 1: Turn the wafer over and place it on the wafer stage, with the side of the wafer to be cleaned facing downward;

[0015] Step 2: turning on the axial flow fan to allow air to pass through the interior of the cabinet to purge the interior of the vacuum cleaning chamber in the cabinet;

[0016] Step 3: opening the exhaust port to allow the purged particles to pass through the third filter and be drawn away through the exhaust port;

[0017] Step 4: lower the first shell by adjusting the lifting column on the top of the cabinet through the cylinder, so that the first shell and the second shell are closed, and fix the edge of the wafer through the positioning column so that the wafer is tightly attached to the fixing pad;

[0018] Step 5: Turn on the vacuum pump of the adsorption chamber to put the inside of the vacuum cleaning chamber into a sub-vacuum state;

[0019] Step 6: The brush head is brought close to the wafer surface by adjusting the lifting axis, and the wafer surface is rotationally brushed.

[0020] Step 7: Turn on the vacuum pump of the adsorption chamber to allow the scrubbed particles to pass through the adsorption holes on the brush head and enter the adsorption chamber.

[0021] The beneficial effects of the present invention are as follows: the device for cleaning particles on the surface of a wafer provided by the present invention is to place the surface of the wafer to be cleaned face down in a vacuum cleaning chamber, perform rotary brushing through a cleaning component, evacuate the vacuum cleaning chamber through an adsorption chamber, adsorb particles that fall after brushing, and reduce particle pollution. The vacuum environment can significantly reduce particle pollution in the air, and prevent external dust or other tiny particles from adhering to the surface of the wafer, thereby improving cleanliness and production yield. In a conventional environment, the surface of the wafer is easily reacted with oxygen in the air, resulting in the formation of an oxide layer. Vacuum brushing can prevent this oxidation phenomenon and ensure that the surface remains clean and pure. The removal of pollutants in a vacuum environment is more thorough, and stubborn organic or inorganic substances, especially fine particles and residual chemicals, can be effectively removed. Brushing the surface of the wafer can reduce the residual chemicals used in the cleaning process, thereby reducing the risk of chemical corrosion or adverse reactions. The process parameters can be better controlled, the fluctuation of the external environment can be reduced, and the repeatability and stability of the process can be increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 A device for cleaning particles from a wafer surface provided by an embodiment of the present invention;

[0024] Figure 2 for Figure 1 The schematic diagram of the vacuum cleaning chamber structure is shown;

[0025] Figure 3 for Figure 1 Schematic diagram of the cleaning component structure shown.

[0026] Description of reference numerals:

[0027] 1-cabinet, 2-first shell, 3-second shell, 4-vacuum cleaning chamber, 5-cleaning component, 6-adsorption chamber, 7-wafer, 8-axial flow fan, 9-cylinder, 10-first filter, 11-second filter, 12-third filter, 13-exhaust port;

[0028] 21-lifting column, 31-fixing pad, 32-positioning column, 33-sealing ring, 51-brush, 52-adsorption hole, 53-lifting shaft, 61-vacuum tube. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] In the present invention, the terms "first", "second", etc. are mainly used to distinguish different devices, elements or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance and quantity of the indicated devices, elements or components. Unless otherwise specified, "plurality" means two or more.

[0031] The following is a detailed description of the implementation of the present invention in conjunction with the specific drawings:

[0032] Figure 1 The present invention provides a device for cleaning particles on the surface of a wafer, the device comprising: a cabinet 1 and a first shell 2 and a second shell 3 arranged in the cabinet 1, the first shell 1 and the second shell 2 symmetrically buckle to form a vacuum cleaning chamber 4, a cleaning component 5 is arranged in the vacuum cleaning chamber 4, the cleaning component 5 is arranged near the second shell 3, and is used to scrub the surface dirt of the wafer 7, the end of the second shell 2 away from the first shell 1 is connected to the adsorption chamber 6, the adsorption chamber 6 is provided with a vacuum pump (not shown in the figure) and a vacuum tube 61 connected to the vacuum pump, the end of the vacuum tube 61 is connected to the side wall of the adsorption chamber 6, so that the vacuum cleaning chamber 4 is in a sub-vacuum state, the cleaning component 5 rotates from the lower end to scrub particles on the surface of the wafer, and the scrubbed particles enter the adsorption chamber 6 due to gravity and adsorption to be collected. The adsorption chamber 6 is arranged outside the cabinet 1 and is detachably connected to the cabinet 1, so that it is convenient to take out the particles that fall after scrubbing.

[0033] In the semiconductor wet process, chemical liquid is used to wet etch or de-glue the wafer, and finally pure water is used to soak and rinse the wafer surface to achieve the cleaning effect. However, usually due to the dirty tank or the influence of pure water particles, there are 0.3um-1um particles on the wafer surface. These particles will be adsorbed in the grooves on the wafer surface. It is impossible to clean them up by just purging with nitrogen. Therefore, the inverted brushing and sub-vacuum adsorption method are used, which has a higher cleaning efficiency.

[0034] An axial flow fan 8 is also provided on one side of the cabinet 1, and an exhaust port 13 is provided on the other side. The axial flow fan 8 and the exhaust port 13 are symmetrically arranged along the vacuum cleaning chamber 4. The wind from the axial flow fan 8 blows away particles on the wafer 7 in a horizontal direction, making it easier to further clean the wafer 7.

[0035] The air inlet and outlet of the axial flow fan 8 are respectively provided with a first filter 10 and a second filter 11, and a third filter 12 is provided on the side close to the exhaust port 13 on the cabinet 1. The exhaust port 13 is connected to an external exhaust fan to extract the air in the cabinet. The first filter 10, the second filter 11 and the third filter 13 are all arranged in parallel and perpendicular to the wind direction. The first filter 10, the second filter 11 and the third filter are all 0.3um filters to prevent large particles in the air from entering the cabinet 1. At the same time, the particles in the vacuum cleaning chamber 4 are purged in advance. The axial flow fan uses high-purity gas (such as nitrogen or dry air) to remove surface residues. Purge uses airflow to physically blow away tiny particles attached to the surface of the wafer to prevent them from having adverse effects on the microstructure of the wafer, thereby improving the yield. In wafer processing, static electricity easily adsorbs particles, and purging can help eliminate static electricity accumulation and further reduce the probability of contaminants attaching. After the wet cleaning or etching process, purging can effectively remove residual moisture or chemicals to prevent these residual substances from affecting the wafer surface. Using an inert gas (such as nitrogen) to purge the wafer surface can effectively block the oxygen in the air, thereby preventing the wafer from oxidizing in a high temperature or exposed environment. Purging is very effective in the drying process after cleaning, which can quickly remove moisture from the wafer surface, prevent the formation of water stains and stains, and improve surface cleanliness. In the drying step after wet processing, gas purging is a fast and effective means to significantly reduce drying time and improve production efficiency.

[0036] Figure 2 for Figure 1 The schematic diagram of the vacuum cleaning chamber is as follows: Figure 2 As shown, the first shell 2 and the second shell 3 are symmetrically buckled to form a vacuum cleaning chamber 4. A lifting column 21 perpendicular to the first shell is provided on the upper part of the first shell 2. In this embodiment, the lifting columns are four groups arranged circumferentially along the edge of the upper surface of the first shell 2. The lifting columns 21 are fixedly connected to the first shell 2 and movably connected to the cylinder 9 on the top of the cabinet 1. The lifting and lowering of the first shell 2 is controlled by the cylinder 6. When the vacuum cleaning chamber 4 is closed, the first shell 2 is pressed against the second shell 3 to make the vacuum cleaning chamber 4 airtight.

[0037] The second shell 3 is fixedly connected to the cabinet 1, the adsorption chamber 6 is arranged on the outside of the cabinet 1, the bottom of the second shell 3 is connected to the adsorption chamber 6, and a fixing pad 31 and a positioning column 32 are provided on the second shell 3. The fixing pad 31 and the positioning column 32 together constitute a wafer carrier for placing the wafer 7 to be cleaned. In the present embodiment, the fixing pad 31 is made of silicone and contacts with the surface of the wafer. Four groups of positioning columns 32 fix the wafer 7 on all sides to prevent the wafer 7 from shifting during the scrubbing process.

[0038] A sealing ring 33 is also provided on the second shell 3. The sealing ring 33 is arranged on the outermost side of the second shell 3 close to the first shell 2 and is used to seal the vacuum cleaning chamber 4. The sealing ring 33 is made of rubber. The fixing pad 31, the positioning column 32 and the sealing ring 33 are all arranged on the side of the second shell 3 close to the first shell 2, and the fixing pad 31, the positioning column 32 and the sealing ring 33 are arranged in sequence from the inside to the outside along the circumference of the second shell. The diameter of the sealing ring 33 is smaller than the diameter of the upper surface of the second shell 3.

[0039] The first shell 2, the second shell 3 and the positioning column are all made of ceramic material to improve the strength of the vacuum cleaning chamber 4. Ceramic materials have low gas permeability and can effectively prevent air or other gases from penetrating into the vacuum environment, ensuring that a highly stable vacuum state is maintained in the container. This is crucial for semiconductor manufacturing and precision experiments. Ceramic materials show excellent stability in high temperature environments and will not deform or soften like metals or other materials. Ceramics are highly chemically inert to many chemicals and can resist erosion by corrosive gases or liquids. The residual etching liquid on the surface of the wafer is corrosive, and the ceramic cavity is not easily corroded. Ceramic materials generally have a low coefficient of thermal expansion, which means that under extreme temperature changes, the size of the ceramic changes less, and the structural integrity of the container can be maintained, and vacuum leakage or structural damage will not occur due to expansion or contraction. Ceramics are good electrical insulators and are suitable for vacuum sealed containers that require an electrically insulating environment, especially in semiconductor manufacturing, electronic device packaging and other applications that need to avoid electrical interference. Ceramic materials have high mechanical strength and can withstand mechanical stress and external impact that vacuum containers may encounter during operation. At the same time, ceramic materials are relatively light, reducing the weight burden of the container. Ceramic materials have high hardness and good wear resistance. They are suitable for use in high-precision machinery or equipment that runs for a long time, and are easy to use and clean. They can maintain stable physical and chemical properties for a long time in a vacuum environment to ensure service life. Ceramic materials have a smooth surface, are not easy to absorb particulate matter or other pollutants, and do not produce volatile substances.

[0040] Figure 3 for Figure 1 The schematic diagram of the cleaning component structure is as follows: Figure 3As shown, the cleaning component 5 includes a brush head and a lifting shaft 53. The brush head is provided with a brush 51 and an adsorption hole 52. The lifting shaft 53 is arranged on the central axis of the brush head in the vertical direction. The lifting shaft 53 is used to adjust the height of the brush head so that the brush head is close to the surface of the wafer 7. The brush 51 includes a plurality of clusters of bristles. In this embodiment, each cluster of bristles is a polyvinyl alcohol (PVA) soft brush with a length of 1 cm and a diameter of 10 um. The bristles are convenient for cleaning particles in the grooves on the surface of the wafer 7 without damaging the surface of the wafer. The brush head is also provided with a plurality of adsorption holes 52. The adsorption holes 52 penetrate the brush head in a direction parallel to the axis of the lifting shaft 53. The adsorption holes 52 are arranged on the brush head at intervals from the bristles to discharge the particles dropped after brushing. The particles enter the adsorption chamber 6 through the opening at the bottom of the second shell 3.

[0041] Inverted brushing is a method of cleaning by combining gravity and mechanical brushing. Compared with traditional flat brushing, it can reduce the reattachment of particles: inverted brushing uses gravity to prevent the removed particles from falling back onto the wafer surface by placing the wafer surface downward. This reduces the risk of secondary attachment of particles, thereby improving the cleaning effect. During the inverted brushing process, particles and contaminants are more easily removed by the mechanical force of the brush, especially stubborn particles, which improves the overall cleaning efficiency. Inverted placement allows the cleaning liquid to be discharged from the wafer surface more quickly, reducing residual liquid. If the cleaning liquid is retained on the wafer surface, it may leave stains or water stains, which inverted brushing effectively avoids. Inverted brushing allows the brush to contact the wafer surface more effectively, especially when removing tiny particles and contaminants. The pressure applied to the wafer by the brush under the action of gravity is more uniform, thereby improving the comprehensiveness of cleaning. The wafer surface after inverted brushing is usually cleaner, without residual particles or liquid, and is suitable for process steps that require a highly clean surface, such as photolithography or coating processes, to ensure process stability and quality.

[0042] The present invention also provides a method for cleaning particles on a wafer surface, comprising:

[0043] Step 1: Turn the wafer over and place it on the wafer stage, with the side of the wafer to be cleaned facing downward;

[0044] Step 2: turning on the axial flow fan to allow air to pass through the interior of the cabinet to purge the interior of the vacuum cleaning chamber in the cabinet;

[0045] Step 3: opening the exhaust port to allow the purged particles to pass through the third filter and be drawn away through the exhaust port;

[0046] Step 4: lower the first shell by adjusting the lifting column on the top of the cabinet through the cylinder, so that the first shell and the second shell are closed, and fix the edge of the wafer through the positioning column so that the wafer is tightly attached to the fixing pad;

[0047] Step 5: Turn on the vacuum pump of the adsorption chamber to put the inside of the vacuum cleaning chamber into a sub-vacuum state;

[0048] Step 6: The brush head is brought close to the wafer surface by adjusting the lifting axis, and the wafer surface is rotationally brushed.

[0049] Step 7: Turn on the vacuum pump of the adsorption chamber to allow the scrubbed particles to pass through the adsorption holes on the brush head and enter the adsorption chamber.

[0050] Before step 1, the method further includes: lifting the first shell through a lifting column on the first shell by using a cylinder to open the vacuum cleaning chamber.

[0051] This method scrubs the wafer surface upside down so that the particles on the wafer surface fall into the adsorption chamber due to gravity, and at the same time, the scrubbing and cleaning chamber is in a sub-vacuum state to reduce particle contamination: the vacuum environment can significantly reduce particle contamination in the air and prevent external dust or other tiny particles from adhering to the wafer surface, thereby improving cleanliness and production yield. In a conventional environment, the wafer surface is easily reacted with oxygen in the air, resulting in the formation of an oxide layer. Vacuum scrubbing can prevent this oxidation phenomenon, ensuring that the surface remains clean and pure, which is beneficial to subsequent process steps. Contaminants are removed more thoroughly in a vacuum environment, and stubborn organic or inorganic substances, especially fine particles and residual chemicals, can be effectively removed. Scrubbing the wafer surface under vacuum conditions can reduce the residual chemicals used in the cleaning process, thereby reducing the risk of chemical corrosion or adverse reactions. Improve process stability: Performing the scrubbing process in a vacuum can better control process parameters, reduce fluctuations in the external environment, and increase the repeatability and stability of the process.

[0052] Obviously, the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

[0053] Note that in the description of this specification, the description with reference to the terms "some embodiments", "other embodiments", etc. means 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 representation of the above terms does 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.

Claims

1. A device for cleaning particles on a wafer surface, characterized in that: include: A first shell, a second shell and an adsorption chamber, wherein the first shell and the second shell are symmetrically buckled together to form a vacuum cleaning chamber, a cleaning component is arranged in the vacuum cleaning chamber, and the second shell is connected to the adsorption chamber.

2. A device for cleaning particles from a wafer surface as claimed in claim 1, characterized in that: An opening is provided on one side of the second shell close to the adsorption chamber and communicated with the adsorption chamber. A vacuum pump is provided in the adsorption chamber. A vacuum tube is provided on the side wall of the adsorption chamber. The vacuum pump is connected to the vacuum tube.

3. A device for cleaning particles from a wafer surface as claimed in claim 1, characterized in that: include: A wafer stage is provided on one side of the second shell close to the first shell. The wafer stage includes a fixing pad and a positioning column. The fixing pad and the positioning column are both arranged along the circumference of the second shell.

4. A device for cleaning particles from a wafer surface as claimed in claim 3, characterized in that: A sealing ring is further provided on a side of the second shell close to the first shell. The sealing ring is arranged along the circumference of the second shell, and the diameter of the sealing ring is greater than the diameter of the wafer stage.

5. A device for cleaning particles from a wafer surface as claimed in claim 1, characterized in that: The cleaning assembly includes a brush head and a lifting shaft fixedly connected to the brush head, a plurality of tufted brushes are provided on the side of the brush head facing the first shell, and a plurality of adsorption holes are also provided on the brush head, and the adsorption holes penetrate the brush head in a direction parallel to the axis of the lifting shaft.

6. A device for cleaning particles from a wafer surface as claimed in claim 1, characterized in that: The device also includes a cabinet, the vacuum cleaning chamber is arranged in the cabinet, an axial flow fan is arranged on one side of the cabinet, and an exhaust port is arranged on the other side, and the axial flow fan and the exhaust port are symmetrically arranged along the two sides of the vacuum cleaning chamber.

7. A device for cleaning particles from a wafer surface as claimed in claim 6, characterized in that: A first filter is provided on the side of the axial flow fan close to the vacuum cleaning chamber, a second filter is provided on the side of the axial flow fan away from the vacuum cleaning chamber, and a third filter is provided on the side of the exhaust port close to the vacuum cleaning chamber. The first filter, the second filter and the third filter are all arranged in parallel.

8. A device for cleaning particles from a wafer surface as claimed in claim 6, characterized in that: A lifting column is provided on a side of the first shell away from the second shell, a cylinder is provided on the top of the cabinet, and the lifting column is movably connected to the cylinder.

9. A device for cleaning particles from a wafer surface as claimed in claim 1, characterized in that: The first shell, the second shell and the positioning column are all made of ceramic, the sealing ring is made of rubber, and the fixing pad is made of silicone.

10. A method for cleaning particles on a wafer surface, characterized in that: include: Step 1: Turn the wafer over and place it on the wafer stage, with the side of the wafer to be cleaned facing downward; Step 2: turning on the axial flow fan to allow air to pass through the interior of the cabinet to purge the interior of the vacuum cleaning chamber in the cabinet; Step 3: opening the exhaust port to allow the purged particles to pass through the third filter and be drawn away through the exhaust port; Step 4: lower the first shell by adjusting the lifting column on the top of the cabinet through the cylinder, so that the first shell and the second shell are closed, and fix the edge of the wafer through the positioning column so that the wafer is tightly attached to the fixing pad; Step 5: Turn on the vacuum pump of the adsorption chamber to put the inside of the vacuum cleaning chamber into a sub-vacuum state; Step 6: The brush head is brought close to the wafer surface by adjusting the lifting axis, and the wafer surface is rotationally brushed. Step 7: Turn on the vacuum pump of the adsorption chamber to allow the scrubbed particles to pass through the adsorption holes on the brush head and enter the adsorption chamber.

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