Improvement method for adsorbed particles in testing process of particle detector

Abstract

The invention relates to an improvement method for adsorbed particles in a test process of a particle detector, which belongs to the technical field of semiconductor wafer detection equipment and comprises the following operation steps: 1, simultaneously starting a fan and a high-pressure generator; and secondly, the fan sucks air into the air collecting pipe, and the air is blown out downwards through the air outlet pipes to generate airflow. And 3, applying high voltage to the spray point by the high-voltage generator. Under the action of a strong electric field of the needle tip, air flowing through the air outlet pipe is ionized to form airflow containing a large number of positive and negative ions, namely ion wind. And 4, blowing the ionic wind to the detector below and the air around the detector. Through a fan and high-voltage ionization mode, an active electrostatic neutralization environment is created, the problem of electrostatic adsorption generally faced by a silicon wafer and particle detector in testing is effectively solved, and the device has important significance in improving product quality and detection reliability.

Description

Technical Field

[0001] This invention relates to the field of semiconductor wafer inspection equipment technology, and specifically to an improved method for detecting particles adsorbed during the testing process of a particle detector. Background Technology

[0002] In the silicon wafer particle inspection process, electrostatic adsorption is the core cause of secondary contamination of silicon wafer surfaces. Static electricity (voltages up to 500–1000V) is easily generated during the silicon wafer conveying, loading, unloading, and scanning processes within the inspection equipment. This static electricity attracts suspended particles in the air (such as silicon powder and polymer particles with a diameter of 0.05–1μm), leading not only to false positives (misjudging particles as inherent defects in the silicon wafer) but also to a decrease in the cleanliness of the silicon wafer after inspection, affecting the yield of subsequent manufacturing processes.

[0003] When a particle detector is in operation, static electricity is generated on its surface due to friction and other reasons. This static electricity acts like a magnet, attracting airborne particles. This causes these particles to not enter the detector through the normal sampling channel, but instead to be "incorrectly" attracted to critical components of the detector (such as optical windows and sensors). This results in: The measured value is too high: The detector also includes these adsorbed particles in its calculation, resulting in a reading higher than the actual particulate matter concentration in the environment.

[0004] Data distortion: It fails to accurately reflect environmental conditions, affecting the accuracy and reliability of the detection. Summary of the Invention

[0005] This invention addresses the shortcomings of existing technologies by providing an improved method for particle detectors to remove adsorbed particles during testing. By using a fan and high-voltage ionization, an active electrostatic neutralization environment is created, effectively solving the common electrostatic adsorption problem faced by silicon wafers and particle detectors during testing. This method is of great significance for improving product quality and testing reliability.

[0006] The above-mentioned technical problems of the present invention are mainly solved by the following technical solutions: An improved method for detecting adsorbed particles in a particle detector during testing is disclosed. The improved structure includes a detection chamber with an operating table inside, on which the detector is placed. An electrostatic dissipator is located at the top of the detection chamber, facing the detector below. The electrostatic dissipator includes a collecting duct with a fan mounted on it. A high-voltage generator is located on the side of the fan. Several outlet ducts connected to the fan are located at the lower end of the collecting duct, and each outlet duct contains a discharge needle connected to the high-voltage generator's circuitry.

[0007] An improved method for static electricity elimination includes the following steps: Step 1: Start the fan and high-voltage generator simultaneously.

[0008] Step 2: The fan draws air into the air collection duct and blows it downwards through each air outlet duct to generate airflow.

[0009] Step 3: The high-voltage generator applies a high voltage to the discharge needle. Under the influence of the strong electric field at the needle tip, the air flowing through the outlet duct is ionized, forming an airflow containing a large number of positive and negative ions, i.e., "ion wind".

[0010] Step 4: The "ion wind" blows towards the detector below and the air around it.

[0011] A high-voltage generator applies a high voltage to the discharge needle, creating an extremely strong electric field at the needle tip. This electric field ionizes the air molecules flowing through it, breaking them down into positively charged ions and negatively charged ions.

[0012] Preferably, if the detector surface has a negative static charge, it will attract positive ions in the airflow and thus be neutralized; if the detector surface has a positive static charge, it will attract negative ions in the airflow and thus be neutralized.

[0013] As a preferred method, the static electricity on the surface of the detector is neutralized, thus losing its electrostatic attraction to suspended particulate matter in the air; the particulate matter will no longer be "erroneously" adsorbed onto the key components of the detector, thereby ensuring that the detector can accurately reflect the particulate matter situation in the environment.

[0014] Preferably, the testing chamber adopts an aluminum alloy frame structure, and the surface of the aluminum alloy frame is coated with a conductive coating.

[0015] The present invention can achieve the following effects: This invention provides an improved method for removing adsorbed particles during testing in a particle detector. Compared with existing technologies, this method creates an active electrostatic neutralization environment through a combination of a fan and high-voltage ionization, effectively solving the common problem of electrostatic adsorption faced by silicon wafers and particle detectors during testing. This is of great significance for improving product quality and testing reliability.

[0016] Improved detection accuracy: By eliminating electrostatic interference, the measurement values ​​are not lowered or the data is distorted due to particle adsorption.

[0017] Active solution: Unlike passive antistatic materials, this method actively and continuously eliminates static electricity, resulting in a more thorough effect.

[0018] The structure is relatively simple: it consists of mature components such as a fan, a high-voltage generator, and a discharge needle, making it easy to implement and maintain.

[0019] Highly adaptable: It can be easily installed as an improvement module for existing testing rooms.

[0020] This increases the electrostatic elimination efficiency of silicon wafer surfaces from 60%–70% to over 99%, with residual electrostatic voltage ≤100V, 100% coverage of edge areas, and completely blocks the path of electrostatically adsorbed particles. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the present invention.

[0022] Figure 2 This is a schematic diagram of the static dissipation device of the present invention.

[0023] In the diagram: 1. Testing chamber; 2. Static dissipator; 3. Detector; 4. Operating table; 5. High voltage generator; 6. Fan; 7. Collector duct; 8. Exit duct; 9. Discharge needle. Detailed Implementation

[0024] The technical solution of the invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings.

[0025] Example: Figure 1 and Figure 2 As shown, an improved method for detecting adsorbed particles in a particle detector during testing is described. The improved structure includes a detection chamber 1, which is constructed with an aluminum alloy frame and coated with a conductive coating. An operating table 4 is located inside the detection chamber 1, on which the detector 3 is placed. An electrostatic dissipator 2 is located at the top of the detection chamber 1, facing the detector 3 below. The electrostatic dissipator 2 includes a collecting duct 7, a fan 6 mounted on the collecting duct 7, a high-voltage generator 5 located on the side of the fan 6, and nine outlet ducts 8 connected to the fan 6 at the lower end of the collecting duct 7. Each outlet duct 8 contains a discharge needle 9 connected to the circuit of the high-voltage generator 5.

[0026] An improved method for static electricity elimination includes the following steps: Step 1: Start the fan 6 and the high-voltage generator 5 simultaneously.

[0027] Step 2: The fan 6 draws air into the air collection pipe 7 and blows it downward through each air outlet pipe 8 to generate airflow.

[0028] Step 3: The high voltage generator 5 applies a high voltage to the discharge needle 9. Under the influence of the strong electric field at the needle tip, the air flowing through the outlet pipe 8 is ionized, forming an airflow containing a large number of positive and negative ions, namely "ion wind".

[0029] Step 4: "Ion wind" blows towards the detector 3 below and the air around it.

[0030] If the surface of the detector has a negative static charge, it will attract positive ions in the airflow and thus be neutralized.

[0031] If the surface of the detector has a positive static charge, it will attract negative ions in the airflow and thus be neutralized.

[0032] When the static electricity on the surface of the detector is neutralized, it loses its electrostatic attraction to suspended particulate matter in the air; the particulate matter will no longer be "erroneously" adsorbed onto the key components of the detector, thus ensuring that the detector can accurately reflect the particulate matter situation in the environment.

[0033] In summary, the improved method for handling adsorbed particles during testing in this particle detector, through a combination of a fan and high-voltage ionization, creates an active electrostatic neutralization environment. This effectively solves the common problem of electrostatic adsorption faced by silicon wafers and particle detectors during testing, and is of great significance for improving product quality and testing reliability.

[0034] The aim is to overcome the static electricity generated during the conveying, loading, unloading, and scanning processes of existing silicon wafer inspection equipment. A retrofit solution for silicon wafer inspection equipment by adding a static electricity dissipator is provided, with the specific objectives: 1. Improve the static electricity elimination efficiency on the silicon wafer surface to over 99%, reduce the residual static voltage on the silicon wafer surface to ≤100V, and achieve 100% static electricity elimination coverage in the edge area.

[0035] 2. Eliminate static electricity on the loading / unloading platforms and conveyor arms inside the testing equipment; the surface static voltage should be ≤100V, reducing particle adsorption by more than 90%. The above description is only a specific embodiment of the present invention, but the structural features of the present invention are not limited thereto. Any changes or modifications made by those skilled in the art within the scope of the present invention are covered by the patent scope of the present invention.

Claims

1. In a method of improving the detection of particles by a particle counter during a test, the improvement comprising: The improved structure includes a testing chamber (1), an operating table (4) is provided in the testing chamber (1), a testing instrument (3) is placed on the operating table (4), and an electrostatic eliminator (2) is provided on the upper part of the testing chamber (1) facing the testing instrument (3) below; the electrostatic eliminator (2) includes an air collection pipe (7), a fan (6) is provided on the air collection pipe (7), a high voltage generator (5) is provided on the side of the fan (6), and several air outlet pipes (8) connected to the fan (6) are provided at the lower end of the air collection pipe (7), and each air outlet pipe (8) is provided with a discharge needle (9) connected to the phase circuit of the high voltage generator (5); An improved method for static electricity elimination includes the following steps: Step 1: Start the fan (6) and the high-voltage generator (5) simultaneously; Step 2: The fan (6) draws air into the air collection pipe (7) and blows it downward through each air outlet pipe (8) to generate airflow; Step 3: The high voltage generator (5) applies a high voltage to the discharge needle (9); under the action of the strong electric field at the tip of the needle, the air flowing through the air outlet pipe (8) is ionized, forming an airflow containing a large number of positive and negative ions, namely "ion wind"; Step 4: The "ion wind" blows towards the detector (3) below and the air around it.

2. The method of claim 1 wherein the particle detector is improved in that during the test the adsorbed particles are: If the surface of the detector has a negative static charge, it will attract positive ions in the airflow and thus be neutralized; If the surface of the detector has a positive static charge, it will attract negative ions in the airflow and thus be neutralized.

3. The method of claim 2 wherein the particle detector is improved in that during the test the adsorbed particles. When the static electricity on the surface of the detector is neutralized, it loses its electrostatic attraction to suspended particulate matter in the air; the particulate matter will no longer be "erroneously" adsorbed onto the key components of the detector, thus ensuring that the detector can accurately reflect the particulate matter situation in the environment.

4. The method of claim 1 wherein the particle detector is improved by adsorbing particles during testing, and wherein: The testing chamber (1) adopts an aluminum alloy frame structure, and the surface of the aluminum alloy frame is coated with a conductive coating.

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