Particle pollution control packaging method and system for wafer box

Abstract

The invention discloses a particle pollution control packaging method and system for a wafer box, and particularly relates to the technical field of semiconductor manufacturing, and the method comprises the steps: removing pollutants through plasma and ultrasonic cleaning; gas replacement is performed to generate stable nitrogen laminar flow; a drying agent is conveyed through a track and filled through a photoelectric sensor; sealing with an adhesive tape and covering with a protective film; operation data are collected and analyzed, parameters are dynamically adjusted, and continuous optimization is achieved. According to the particle pollution control packaging method and system for the wafer box, the complete wafer box particle pollution control system is constructed through the steps of cleaning before packaging, gas replacement, drying agent filling, adhesive tape sealing, protective film covering and the like and cooperative operation of corresponding system modules; pollutants on the surface of the wafer box are removed, external pollution particles are isolated, moisture in the box is controlled, physical protection is enhanced, particle pollution control over the whole packaging process of the wafer box is achieved, and the quality safety of wafers in the storage and transportation process is guaranteed.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing technology, and particularly relates to a particle contamination control packaging method and system for a wafer cassette. Background Art

[0002] In the semiconductor manufacturing industrial chain, the wafer is the core raw material, and the storage and transportation links after its production are crucial. As a professional carrier container, the wafer cassette can accurately fix the wafer by virtue of the internal symmetrical groove design, avoiding physical collision damage during transportation; at the same time, it uses anti-static materials to effectively prevent potential hazards caused by static electricity to the wafer. In addition, the closed space formed by the internal sealing rubber ring of the wafer cassette makes conventional wafer manufacturers think that additional tape sealing and fixing are not required to meet the daily transportation and storage needs.

[0003] However, in actual application scenarios, obvious drawbacks are exposed in the wafer cassettes for long-term storage. Through research, it is found that for wafer cassettes not sealed and fixed with an outer tape, after 3 to 12 months of long-term storage, the particle contamination on the wafer surface is significantly aggravated. The particle concentration with a diameter of 0.16 - 0.3 μm increases by as much as 30% - 50%. And high-end chip manufacturing has almost stringent standards for particle contamination control. For example, it is required that the number of particles with a diameter ≤ 0.1 μm should be strictly controlled within 100 pieces / cm 2 Below, this pollution problem seriously affects the wafer quality and poses a hidden danger to the yield rate of chip manufacturing, and an effective solution needs to be urgently sought. Summary of the Invention

[0004] The main purpose of the present invention is to provide a particle contamination control packaging method and system for a wafer cassette, which can effectively solve the problems involved in the above background art.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] A particle contamination control packaging method for a wafer cassette, the method comprising the following steps:

[0007] S1. Conduct pre-packaging cleaning, and use the synergistic effect of plasma and ultrasonic waves to remove pollutants;

[0008] S2. Conduct gas replacement for the wafer cassette, control the flow rate and opening time of the nitrogen filling port, and generate a stable nitrogen laminar flow state;

[0009] S3. Conduct desiccant filling, and detect the number of desiccants through an orbital conveying system and a photoelectric sensor and push them into the wafer cassette;

[0010] S4. Implement tape sealing and protective film covering to complete basic sealing and enhance scratch resistance;

[0011] S5. Collect and analyze the operation data of each link, including but not limited to nitrogen flow rate, desiccant quantity, tape sticking pressure, and cleaning time, evaluate the performance indicators of each link, and generate an optimized adjustment plan for the packaging process;

[0012] S6. Dynamically adjust the parameters according to the optimization results to achieve continuous optimization.

[0013] Preferably, in the gas displacement step in S2, the diameter range of the top nitrogen filling port is 4 - 6 mm, the diameter range of the sidewall nitrogen filling port is 1.5 - 2.5 mm, and the sidewall nitrogen filling ports are staggeredly distributed; the flow rate range of the top nitrogen filling port is 90 - 110 L / min, the opening time is 8 - 12 seconds, and the flow rate range of the sidewall nitrogen filling port is 15 - 25 L / min.

[0014] Preferably, in the desiccant loading step in S3, the desiccants are grouped according to the quantity required for each box, and each group of desiccants is placed in an independent pushing groove; the optoelectronic sensor detects the grouped quantity of desiccants, and if it is less than the set value, an alarm is issued; the grouped pushing unit pushes the desiccants into the wafer box at a speed range of 8 - 12 cm / s.

[0015] Preferably, in the tape sealing step in S4, a static - electricity - proof tape with a thickness of 0.08 - 0.12 mm is wound around the joint of the wafer box lid to complete the basic sealing; a transparent polyurethane protective film covers the outer layer of the static - electricity - proof tape, and the sticking pressure range is 0.4 - 0.9 N / cm2.

[0016] 5. According to the method for controlling particle contamination packaging for a wafer box described in claim 1, preferably, in the pre - packaging cleaning step in S1, hydrogen is introduced, the air pressure range is controlled at 13 - 17 Pa, the power range is 120 - 140 W, and the treatment time range is 3 - 5 minutes; the frequency range of the ultrasonic generating device is 38 - 62 kHz, the power range is 180 - 220 W, and the treatment time range is 1.5 - 2.5 minutes.

[0017] Preferably, in the step of optimizing and adjusting the packaging process based on the data of each link in S5,

[0018] S5.1. Collect the operation data of each link, including but not limited to nitrogen flow rate, desiccant quantity, tape sticking pressure, and cleaning time;

[0019] S5.2. Analyze the correlation of the data of each link, and evaluate the stability of nitrogen laminar flow displacement, the accuracy of desiccant loading, the integrity of tape sealing, and the improvement of cleaning effect;

[0020] S5.3. Based on the analysis results, determine the direction and amplitude of optimization and adjustment, and generate the optimized integration result of the packaging process.

[0021] Preferably, in the dynamic optimization and adjustment step in S6,

[0022] S6.1. Dynamically adjust the parameters in steps 1 to 4 based on the optimized integration result of the packaging process;

[0023] S6.2. According to the nitrogen laminar flow replacement result, for every 1 unit difference in turbulence intensity, adjust the flow rate of the top nitrogen filling port by ±5 L / min; for every 1 unit difference in replacement efficiency, adjust the opening time by ±1 second;

[0024] S6.3. According to the detection result of the desiccant filling quantity, for every 1 unit difference in quantity, adjust the detection threshold of the photoelectric sensor by ±0.1 unit; for every 1 unit difference in pushing efficiency, adjust the pushing speed by ±1 cm / s;

[0025] S6.4. According to the tape sealing and protection result, for every 1 unit difference in sealing integrity, adjust the thickness of the anti-static tape by ±0.01 mm; for every 1 unit difference in adhesion, adjust the pasting pressure of the polyurethane protective film by ±0.1 N / cm 2 ;

[0026] S6.5. According to the cleaning synergy enhancement result, for every 1 unit difference in cleanliness, adjust the plasma treatment pressure by ±1 Pa; for every 1 unit difference in removal rate, adjust the treatment time by ±0.5 minutes; for every 1 unit difference in synergy effect, adjust the ultrasonic frequency by ±2 kHz;

[0027] S6.6. Through the above dynamic adjustment, generate dynamic optimization and adjustment parameters and feedback them to steps 1 to 4 to achieve continuous optimization of the packaging process.

[0028] A particle contamination control packaging system for a wafer cassette, which uses the above-mentioned particle contamination control packaging method for a wafer cassette to package the wafer cassette. The system includes the following modules:

[0029] A cleaning enhancement module for performing the pre-packaging cleaning step described in S1;

[0030] A nitrogen filling control module for performing the gas replacement step described in S2;

[0031] A desiccant filling module for performing the desiccant filling step described in S3;

[0032] A sealing and protection module for performing the tape sealing and protective film covering steps described in S4;

[0033] A process optimization module for performing the optimization and adjustment step of the packaging process based on the data of each link described in S5;

[0034] A dynamic adjustment module for performing the step of dynamically adjusting the parameters of each link according to the optimization adjustment scheme described in S6.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1. Through steps such as pre-packaging cleaning, gas replacement, desiccant filling, tape sealing, and protective film covering, and the coordinated operation of corresponding system modules, the present invention constructs a complete particle pollution control system for wafer boxes, which can effectively remove contaminants on the surface of wafer boxes, isolate external pollution particles, control the humidity inside the box, and enhance physical protection, realizing particle pollution control throughout the packaging process of wafer boxes and ensuring the quality and safety of wafers during storage and transportation.

[0037] 2. The present invention adopts a synergistic cleaning process of plasma and ultrasonic waves. The chemical reaction of plasma is used to decompose contaminants, and the cavitation effect of ultrasonic waves is used to peel off stubborn impurities. The combination of the two can efficiently remove various contaminants such as dust and oil stains on the surface of wafer boxes, providing a clean initial state for wafer boxes and reducing the potential risk of particle pollution during the packaging process from the source.

[0038] 3. By optimizing the diameter, distribution, flow rate, and time parameters of the nitrogen filling port, a stable and uniform nitrogen laminar flow is formed inside the wafer box, effectively replacing the air inside the box and isolating the intrusion of external pollution particles, creating a clean storage environment for wafers, reducing the risk of wafer pollution caused by the intrusion of external particles, and improving the cleanliness control ability during the packaging process.

[0039] 4. Through multiple protection measures such as desiccant filling, antistatic tape sealing, and covering with a transparent polyurethane protective film, the present invention realizes the adsorption control of moisture inside the box, physical sealing at the joints, and surface scratch resistance protection. It can not only prevent wafer oxidation caused by moisture condensation but also block the particle intrusion path and protect the surface of the wafer box, comprehensively improving the sealing performance and comprehensive protection ability of the wafer box. Description of the Drawings

[0040] Figure 1 is a flowchart of the packaging method of the present invention;

[0041] Figure 2 is a box plot of the particle number distribution under different storage times of the present invention;

[0042] Figure 3 is an interaction diagram of 0.16um particles of the present invention;

[0043] Figure 4 is an interaction diagram of 0.2um particles of the present invention;

[0044] Figure 5 is an interaction diagram of 0.3um particles of the present invention. Detailed Embodiments

[0045] To make the technical means, creative features, achieved objectives and effects of the present invention easily understood, the present invention will be further described below in conjunction with specific embodiments.

[0046] The present invention relates to a particle contamination control packaging method and system for a wafer cassette, aiming to effectively control particle contamination during the packaging process of the wafer cassette through a series of scientific and rigorous steps and corresponding functional modules, and ensure the quality and safety of wafer products during packaging, transportation and storage. The specific embodiments will be described in detail below.

[0047] As Figure 1 shown, the present invention discloses a particle contamination control packaging method for a wafer cassette. The specific steps of this method include pre-packaging cleaning, gas replacement, desiccant filling, and tape sealing and protective film covering;

[0048] Specifically, for the pre-packaging cleaning step of step S1, it is a key step to remove contaminants on the surface of the wafer cassette. The present invention adopts the synergistic action of plasma and ultrasonic waves to achieve the cleaning of the surface of the wafer cassette;

[0049] During the cleaning process, hydrogen is introduced, and the air pressure range is controlled at 13 - 17 Pa, the power range is 120 - 140 W, and the treatment time range is 3 - 5 minutes; at the same time, the frequency range of the ultrasonic generator is 38 - 62 kHz, the power range is 180 - 220 W, and the treatment time range is 1.5 - 2.5 minutes.

[0050] Taking specific data as an example, when the hydrogen pressure is 15 Pa, the power is 130 W, and the treatment time is 4 minutes; when the frequency of the ultrasonic generator is 50 kHz, the power is 200 W, and the treatment time is 2 minutes, the plasma can chemically react with the contaminants on the surface of the wafer cassette to decompose or vaporize them; the ultrasonic waves, through the cavitation effect generated by high-frequency vibration, can peel off stubborn contaminants from the surface of the wafer cassette. The synergistic action of the two can effectively remove various contaminants on the surface of the wafer cassette, including dust, oil stains, etc.;

[0051] Furthermore, for the gas replacement step of step S2, its purpose is to form a stable nitrogen laminar flow state inside the wafer cassette to isolate possible contaminant particles in the outside world and provide a clean environment for the wafer. This step is achieved by setting nitrogen filling ports with specific diameters and distributions and precisely controlling the flow rate and opening time of the nitrogen filling ports.

[0052] On the wafer cassette, the diameter of the top nitrogen filling port is designed to be 4 - 6 mm, and the diameter of the sidewall nitrogen filling port is 1.5 - 2.5 mm, and the sidewall nitrogen filling ports are arranged in a staggered manner. This design can make nitrogen more evenly distributed inside the wafer cassette and avoid dead corners where gas replacement is insufficient;

[0053] Specifically, the flow rate of the top nitrogen filling port is controlled at 90 - 110 L / min, and the opening time is 8 - 12 seconds; the flow rate range of the sidewall nitrogen filling port is 15 - 25 L / min;

[0054] For example, in actual operation, when the diameter of the top nitrogen filling port is 5 mm, the flow rate is set at 100 L / min, the opening time is 10 seconds, the diameter of the sidewall nitrogen filling port is 2 mm, and the flow rate is set at 20 L / min, through the coordination of gas flow rate and time, a nitrogen laminar flow can be quickly and stably formed inside the wafer cassette, and the original air and possible contaminant particles inside the cassette can be fully displaced.

[0055] Furthermore, for the step S3 of desiccant loading, its main function is to remove the possible moisture inside the wafer cassette, prevent problems such as water vapor condensation and oxidation on the wafer surface caused by moisture, and thus affect the wafer performance. This step realizes the accurate loading of desiccant through the collaborative work of the track conveying system and the photoelectric sensor.

[0056] The desiccants are grouped according to the quantity required for each cassette, and each group of desiccants is placed in an independent pushing groove. The photoelectric sensor real-time detects the grouped quantity of desiccants. Once the detected quantity is less than the set value, an alarm will be immediately issued to remind the operator to replenish the desiccants in time; the grouped pushing unit pushes the desiccants into the wafer cassette at a speed range of 8 - 12 cm / s.

[0057] For example, if a certain type of wafer cassette requires 5 packs of desiccants per cassette, the desiccants are divided into 5 groups and placed in the pushing groove, and the photoelectric sensor real-time monitors the presence status of each group of desiccants; when the pushing unit pushes the desiccants into the wafer cassette at a speed of 10 cm / s, the desiccant loading work can be completed quickly and accurately, ensuring both the loading efficiency and the accuracy of the quantity of desiccants in each wafer cassette.

[0058] For the step S4 of tape sealing and protective film covering, it is mainly used for physically sealing and surface protection of the wafer cassette. An anti-static tape with a thickness of 0.08 - 0.12 mm is wound around the joint of the wafer cassette lid to complete the basic sealing work, preventing external particles from entering the wafer cassette through the joint. At the same time, a transparent polyurethane protective film is covered on the outer layer of the anti-static tape to enhance the scratch resistance performance and protect the surface of the wafer cassette from damage during handling and storage.

[0059] In actual operation, the winding of the anti-static tape needs to be closely attached to the joint to ensure the sealing effect, and the pasting pressure of the transparent polyurethane protective film is controlled at 0.4 - 0.9 N / cm 2 ;

[0060] When the pasting pressure is set at 0.6 N / cm 2When in use, it can firmly paste the protective film on the surface of the anti-static tape, and will not cause the deformation or damage of the anti-static tape due to excessive pressure, effectively improving the sealing and protection performance of the wafer cassette.

[0061] Furthermore, due to differences in production environment, raw material batch composition content, etc., even under established raw materials and production parameters, the key quality parameters of the product may still fluctuate. The present invention further sets up steps S5 for collecting and analyzing data and S6 for dynamic optimization and adjustment;

[0062] In step S5, by collecting the operation data of each link such as nitrogen gas flow rate, desiccant quantity, tape sticking pressure, cleaning treatment time, etc., and analyzing the correlation of the data of each link, evaluate the stability of nitrogen laminar flow replacement, the accuracy of desiccant filling, the integrity of tape sealing, and the improvement of cleaning effect, so as to determine the direction and range of optimization and adjustment, and generate the optimized integration result of the packaging process.

[0063] For example, through the analysis of a large amount of packaging data, it is found that when the combination of nitrogen gas flow rate and opening time is unreasonable, the nitrogen laminar flow state is unstable, resulting in a small amount of pollution particles still existing in some wafer cassettes;

[0064] Based on this analysis result, in step S6, dynamic optimization and adjustment are carried out on the gas replacement link, and the flow rate range and opening time range of the top and side wall nitrogen filling ports are adjusted according to the optimized integration result to further optimize the nitrogen laminar flow state;

[0065] Specifically, based on the optimized integration result of the packaging process, the parameters in steps 1 to 4 are dynamically adjusted;

[0066] According to the nitrogen laminar flow replacement result, for every 1 unit difference in turbulence intensity, the flow rate of the top nitrogen filling port is adjusted by ±5 L / min; for every 1 unit difference in replacement efficiency, the opening time is adjusted by ±1 second;

[0067] According to the detection result of the desiccant filling quantity, for every 1 unit difference in quantity, the detection threshold of the photoelectric sensor is adjusted by ±0.1 unit; for every 1 unit difference in pushing efficiency, the pushing speed is adjusted by ±1 cm / s;

[0068] According to the tape sealing and protection result, for every 1 unit difference in sealing integrity, the thickness of the anti-static tape is adjusted by ±0.01 mm; for every 1 unit difference in adhesion, the sticking pressure of the polyurethane protective film is adjusted by ±0.1 N / cm 2 ;

[0069] According to the cleaning synergy enhancement result, for every 1 unit difference in cleanliness, the plasma treatment air pressure is adjusted by ±1 Pa; for every 1 unit difference in removal rate, the treatment time is adjusted by ±0.5 minutes; for every 1 unit difference in synergy effect, the ultrasonic frequency is adjusted by ±2 kHz;

[0070] Through the above dynamic adjustment, dynamic optimization adjustment parameters are generated and fed back to Steps 1 to 4 to achieve continuous optimization of the packaging process, so as to correct the effect differences caused by production environment fluctuations or raw material changes.

[0071] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention. For the process parameters not specified under specific conditions in the following embodiments, they are usually in accordance with conventional conditions.

[0072] Based on the above packaging method, 125 wafers of the same batch are divided into 5 groups (25 wafers in each group), and different packaging method combinations (vacuum / nitrogen filling, with / without tape, with / without desiccant) are adopted. The temperature is 15 - 35°C, the humidity is ≤55%RH, and the storage period is 3 - 12 months. Among them, Group A is for three months, Group B is for six months, Group C is for nine months, and Group D is for twelve months. Specifically:

[0073] Example 1: It is processed by adopting the method of vacuum + not winding tape.

[0074] Cleaning before packaging: Use the cleaning enhancement module, introduce hydrogen, set the air pressure to 15 Pa, the power to 130 W, and the processing time to 4 minutes; at the same time, set the frequency of the ultrasonic generating device to 50 kHz, the power to 200 W, and the processing time to 2 minutes to clean the wafer cassette.

[0075] Gas replacement: Use the nitrogen filling control module to evacuate the wafer cassette to a vacuum state without nitrogen filling.

[0076] Subsequent operations: In this example, the operations of desiccant loading, tape sealing, and protective film covering are not performed;

[0077] After detection, due to ineffective sealing, a small amount of dust particles enter the wafer cassette after it is placed for a period of time, and the cleaning effect gradually decreases over time.

[0078] Example 2: It is processed by adopting the method of vacuum + winding tape.

[0079] Cleaning before packaging: The same as Example 1, clean the wafer cassette through the cleaning enhancement module with the same parameter settings.

[0080] Gas replacement: Evacuate the wafer cassette to a vacuum state.

[0081] Tape sealing: Use the sealing protection module to wind an anti-static tape with a thickness of 0.1 mm at the joint of the lid of the wafer cassette to complete the basic sealing. In this embodiment, the operations of filling desiccant and covering the protective film are not carried out;

[0082] After testing, compared with Embodiment 1, due to the effect of tape sealing, the amount of dust particles entering the cassette is significantly reduced. However, due to the lack of nitrogen filling and desiccant loading, there is still a certain risk of moisture influence.

[0083] Embodiment 3: Adopt the method of vacuum + winding tape + desiccant for treatment;

[0084] Cleaning before packaging: Keep the same cleaning operations and parameters as in Embodiment 1.

[0085] Gas replacement: Pump the wafer cassette to vacuum.

[0086] Desiccant loading: Use the desiccant loading module to group the desiccant into 5 packages per cassette. The photoelectric sensor monitors in real time, and the grouping and pushing unit pushes the desiccant into the wafer cassette at a speed of 10 cm / s.

[0087] Tape sealing: Use the sealing protection module to wind an anti-static tape with a thickness of 0.1 mm. In this embodiment, the operations of covering the protective film and nitrogen filling are not carried out;

[0088] After testing, the desiccant effectively reduces the moisture content in the cassette. However, due to the lack of nitrogen filling, there is still a risk that a small amount of oxygen may cause oxidation of the wafer.

[0089] Embodiment 4: Adopt the method of nitrogen filling + winding tape for treatment;

[0090] Cleaning before packaging: The cleaning operations and parameters are the same as in Embodiment 1.

[0091] Gas replacement: Through the nitrogen filling control module, the diameter of the top nitrogen filling port is 5 mm, the flow rate is set to 100 L / min, and the opening time is 10 seconds; the diameter of the sidewall nitrogen filling port is 2 mm, the flow rate is set to 20 L / min, and a nitrogen laminar flow is formed inside the wafer cassette.

[0092] Tape sealing: Use the sealing protection module to wind an anti-static tape with a thickness of 0.1 mm at the joint of the lid of the wafer cassette, and cover a transparent polyurethane protective film on the outer layer of the anti-static tape, and the pasting pressure is set to 0.6 N / cm 2 , and the operation of filling desiccant is not carried out in this embodiment;

[0093] After testing, the nitrogen laminar flow effectively isolates the external pollution particles, and the tape sealing and protective film covering further enhance the protection effect. However, due to the lack of desiccant placement, the moisture inside the cassette is not treated.

[0094] Example 5: Treatment is carried out by means of nitrogen filling + tape winding + desiccant.

[0095] Cleaning before packaging: The same cleaning method and parameters as in Example 1 are adopted to ensure the cleanliness of the surface of the wafer cassette.

[0096] Gas replacement: Using the nitrogen filling control module, gas replacement is carried out according to the parameters of the top nitrogen filling port diameter of 5 mm, flow rate of 100 L / min, opening time of 10 seconds; side wall nitrogen filling port diameter of 2 mm, flow rate of 20 L / min to form a stable nitrogen laminar flow.

[0097] Desiccant loading: Through the desiccant loading module, 5 packs of desiccant per box are grouped and placed. Monitored by the photoelectric sensor, the grouped pushing unit pushes the desiccant into the wafer cassette at a speed of 10 cm / s.

[0098] Tape sealing and protective film covering: Using the sealing and protection module, an anti-static tape with a thickness of 0.1 mm is wound at the joint of the wafer cassette lid, and a transparent polyurethane protective film is covered, and the pasting pressure is 0.6 N / cm 2 ;

[0099] After testing, this example combines the multiple advantages of nitrogen filling to isolate pollution, desiccant to remove moisture, tape sealing and protective film protection. The particle pollution, moisture and surface damage risks in the wafer cassette are effectively controlled, and the packaging effect is the best.

[0100] Based on the wafer cassettes processed in the above five examples for testing, combined with the attached Figures 2 - 5 Analysis shows that:

[0101] Based on Example 1, from the box plot, at different particle sizes (≥0.16 μm, ≥0.2 μm, ≥0.3 μm, ≥RE), as the storage time increases, the number of particles shows an obvious upward trend;

[0102] When stored for 3 months, the number of particles of each particle size is relatively small, but by 12 months, the number of particles ≥0.16 μm reaches 2.08, with a large growth rate. This is because this scheme only performs vacuum treatment and does not perform tape sealing, so it cannot effectively block the entry of external particles, resulting in the accumulation of particle pollution in the wafer cassette over time. At the same time, due to the lack of the action of nitrogen filling and desiccant, the moisture and oxygen that may exist in the box will also have a potential impact on the wafer.

[0103] Compared with Example 1, at the same storage time, the number of particles of each particle size in the wafer cassette in Example 2 is reduced;

[0104] When stored for 12 months, the number of particles ≥ 0.16μm is 1.44, which indicates that the tape seal blocks the entry of external particles into the wafer cassette to a certain extent. However, since nitrogen filling is not carried out, there is still a certain amount of oxygen in the cassette, and there is no desiccant to remove moisture. Therefore, although the particle contamination situation has improved, it will still increase over time.

[0105] Judging from the data, Example 3 has further improvement in controlling particle contamination. The addition of the desiccant effectively reduces the moisture content in the cassette and reduces problems such as particle adsorption caused by moisture.

[0106] When stored for 12 months, the number of particles ≥ 0.16μm is 1.12. However, since nitrogen filling is not carried out, the oxygen in the cassette may still cause reactions such as oxidation on the wafer surface, which in turn affects the particle situation. Therefore, the number of particles will still increase over time, but the growth rate is relatively smaller than that of Example 1 and Example 2.

[0107] The nitrogen filling treatment in Example 4 has a significant effect in isolating external contaminated particles. From Figures 2 to 5 it can be seen that the number of particles of each particle size is relatively stable and small at different storage times;

[0108] When stored for 12 months, the number of particles ≥ 0.16μm is 0.96. The nitrogen laminar flow effectively isolates the entry of external particles. At the same time, the tape seal and the protective film coverage enhance the protection effect. However, due to the absence of a desiccant, the moisture in the cassette may have a certain impact on the wafer. However, from the perspective of particle contamination, the overall protection effect is good.

[0109] Example 5 combines the multiple advantages of nitrogen filling to isolate contamination, desiccant to remove moisture, tape seal and protective film protection. During the entire storage period, the number of particles of each particle size always remains at the lowest level;

[0110] When stored for 12 months, the number of particles ≥ 0.16μm is only 0.56, which fully proves the effectiveness and superiority of the packaging method and system proposed by the present invention in controlling particle contamination in the wafer cassette, and can ensure the quality of the wafer to the greatest extent during long-term storage.

[0111] Through the detection and analysis of the wafer cassettes processed in the above five examples, it is obvious that different packaging methods have significant differences in the control effect of particle contamination in the wafer cassette. The packaging method of Example 5 (nitrogen filling + taping + desiccant) performs best in suppressing particle contamination and can provide the most stable and clean storage environment for the wafer;

[0112] In Example 1 (vacuum + no tape winding), due to insufficient protective measures, the problem of particle contamination is the most serious. The results of this study provide an important reference for selecting appropriate wafer cassette packaging methods in actual production, and further verify the scientificity and practicability of the packaging method and system in the present invention.

[0113] Furthermore, the present invention also discloses a particle contamination control packaging system for a wafer cassette based on the above packaging method. Specifically, the system includes a nitrogen filling control module, a desiccant loading module, a sealing protection module, a cleaning enhancement module, a process optimization module, and a dynamic adjustment module;

[0114] The cleaning enhancement module is used to perform the pre-packaging cleaning step described in S1. It integrates a plasma processing device and an ultrasonic generating device;

[0115] The plasma processing device can introduce hydrogen, and accurately control the air pressure at 13 - 17 Pa, the power at 120 - 140 W, and the processing time at 3 - 5 minutes; the ultrasonic generating device can adjust the frequency at 38 - 62 kHz, the power at 180 - 220 W, and the processing time at 1.5 - 2.5 minutes. The two work together to achieve the cleaning of the wafer cassette.

[0116] The nitrogen filling control module is used to perform the gas replacement step described in S2. This module mainly includes a nitrogen filling port device, a gas flow rate control unit, and a time control unit;

[0117] The nitrogen filling port device is installed according to the design with a top nitrogen filling port diameter of 4 - 6 mm, a sidewall nitrogen filling port diameter of 1.5 - 2.5 mm and a staggered distribution; the gas flow rate control unit can accurately adjust the top nitrogen filling port flow rate at 90 - 110 L / min and the sidewall nitrogen filling port flow rate at 15 - 25 L / min; the time control unit accurately controls the opening time of the nitrogen filling port at 8 - 12 seconds. Through the coordinated work of each part, a stable nitrogen laminar flow state is formed inside the wafer cassette.

[0118] The desiccant loading module is responsible for performing the desiccant loading step described in S3. It consists of an orbital conveying system, a photoelectric sensor detection unit, and a grouping pushing unit;

[0119] The orbital conveying system is used to convey desiccant groups; the photoelectric sensor detection unit monitors the number of desiccant groups in real time and triggers an alarm when the number is less than the set value; the grouping pushing unit pushes the desiccant into the wafer cassette at a speed of 8 - 12 cm / s to ensure that the desiccant is accurately loaded into the wafer cassette.

[0120] The sealing protection module performs the tape sealing and protective film covering steps described in S4. This module includes an anti-static tape winding device and a transparent polyurethane protective film pasting device;

[0121] The anti-static tape winding device can accurately wind an anti-static tape with a thickness of 0.08 - 0.12 mm at the joint of the lid of the wafer cassette; the transparent polyurethane protective film pasting device then covers the protective film on the outer layer of the anti-static tape with a pasting pressure of 0.4 - 0.9 N / cm 2 to complete the sealing and surface protection of the wafer cassette.

[0122] The process optimization module executes the steps of optimizing and adjusting the packaging process based on the data of each link described in S5. By collecting and analyzing the operation data of each link, evaluating the performance indicators of each link, determining the optimization direction and amplitude, and generating the optimized integration result of the packaging process;

[0123] The dynamic adjustment module then executes the steps of dynamically adjusting the parameters of each link according to the optimization adjustment plan described in S6 based on the result generated by the process optimization module, and dynamically adjusts the relevant parameters of the nitrogen filling control module, the desiccant filling module, the sealing protection module, and the cleaning and strengthening module to achieve continuous optimization of the packaging process.

[0124] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A particle contamination control packaging method for a wafer cassette, characterized in that, The method includes the following steps: S1. Conduct pre-packaging cleaning, and use the synergistic effect of plasma and ultrasonic waves to remove pollutants; S2. Conduct gas replacement for the wafer cassette, control the flow rate and opening time of the nitrogen filling port, and generate a stable nitrogen laminar flow state; S3. Load desiccants, detect the quantity of desiccants through an orbital conveying system and a photoelectric sensor, and push them into the wafer cassette; S4. Implement tape sealing and protective film covering to complete basic sealing and enhance scratch resistance; S5. Collect and analyze the operation data of each link, including but not limited to nitrogen flow rate, quantity of desiccants, tape sticking pressure, cleaning treatment time, evaluate the performance indicators of each link, and generate an optimization and adjustment plan for the packaging process; S6. Dynamically adjust parameters according to the optimization results to achieve continuous optimization.

2. A particle contamination control packaging method for a wafer cassette according to claim 1, characterized in that: In the gas replacement step described in S2, the diameter range of the top nitrogen filling port is 4 - 6 mm, the diameter range of the sidewall nitrogen filling port is 1.5 - 2.5 mm, and the sidewall nitrogen filling ports are staggeredly distributed; the flow rate range of the top nitrogen filling port is 90 - 110 L / min, the opening time is 8 - 12 seconds, and the flow rate range of the sidewall nitrogen filling port is 15 - 25 L / min.

3. A particle contamination control packaging method for a wafer cassette according to claim 1, characterized in that: In the desiccant loading step described in S3, the desiccants are grouped according to the quantity required for each cassette, and each group of desiccants is placed in an independent pushing groove; the photoelectric sensor detects the grouped quantity of desiccants, and if it is less than the set value, an alarm is issued; The grouped pushing unit pushes the desiccants into the wafer cassette at a speed range of 8 - 12 cm / s.

4. A method for controlling particle contamination packaging for a wafer cassette according to claim 1, characterized in that: In the tape sealing step described in S4, an anti-static tape with a thickness of 0.08 - 0.12 mm is wound around the joint of the wafer cassette lid to complete basic sealing; a transparent polyurethane protective film is covered on the outer layer of the anti-static tape, and the sticking pressure range is 0.4 - 0.9 N / cm2.

5. A particle contamination control packaging method for a wafer cassette according to claim 1, characterized in that: In the pre-packaging cleaning step described in S1, hydrogen is introduced, the pressure range is controlled at 13 - 17 Pa, the power range is 120 - 140 W, and the treatment time range is 3 - 5 minutes; the frequency range of the ultrasonic generating device is 38 - 62 kHz, the power range is 180 - 220 W, and the treatment time range is 1.5 - 2.5 minutes.

6. A method for controlling particle contamination packaging for a wafer cassette according to claim 1, characterized in that: In the step of optimizing and adjusting the packaging process based on the data of each link described in S5, S5.

1. Collect the operation data of each link, including but not limited to nitrogen flow rate, quantity of desiccants, tape sticking pressure, cleaning treatment time; S5.

2. Analyze the correlation of the data of each link, and evaluate the stability of nitrogen laminar flow replacement, the accuracy of desiccant loading, the integrity of tape sealing, and the improvement of cleaning effect; S5.

3. Based on the analysis results, determine the direction and amplitude of optimization and adjustment, and generate the optimization and integration result of the packaging process.

7. A particle contamination control packaging method for a wafer cassette according to claim 6, characterized in that: In the dynamic optimization and adjustment step described in S6, S6.

1. Dynamically adjust the parameters in steps 1 to 4 based on the optimization and integration result of the packaging process; S6.

2. According to the nitrogen laminar flow replacement result, for every 1 unit difference in turbulence intensity, the flow rate of the top nitrogen filling port is adjusted by ±5 L / min; for every 1 unit difference in replacement efficiency, the opening time is adjusted by ±1 second; S6.

3. According to the detection results of the desiccant filling quantity, for every 1-unit difference, the detection threshold of the photoelectric sensor is adjusted by ±0.1 unit; for every 1-unit difference in the pushing efficiency, the pushing speed is adjusted by ±1 cm / s; S6.

4. According to the tape sealing protection results, for every 1-unit difference in sealing integrity, the thickness of the anti-static tape is adjusted by ±0.01 mm; for every 1-unit difference in adhesion, the sticking pressure of the polyurethane protective film is adjusted by ±0.1 N / cm 2 ; S6.

5. According to the cleaning synergy enhancement results, for every 1-unit difference in cleanliness, the plasma treatment pressure is adjusted by ±1 Pa; for every 1-unit difference in the removal rate, the treatment time is adjusted by ±0.5 minutes; for every 1-unit difference in the synergy effect, the ultrasonic frequency is adjusted by ±2 kHz; S6.

6. Through the above dynamic adjustments, dynamic optimization adjustment parameters are generated and fed back to steps 1 to 4 to achieve continuous optimization of the packaging process.

8. A particle contamination control packaging system for a wafer cassette, which packages the wafer cassette by applying the particle contamination control packaging method for a wafer cassette according to any one of claims 1-7, characterized in that, The system includes the following modules: A cleaning enhancement module for performing the pre-packaging cleaning step described in S1; A nitrogen filling control module for performing the gas replacement step described in S2; A desiccant filling module for performing the desiccant filling step described in S3; A sealing protection module for performing the tape sealing and protective film covering steps described in S4; A process optimization module for performing the optimization and adjustment step of the packaging process based on the data of each link described in S5; A dynamic adjustment module for performing the step of dynamically adjusting the parameters of each link according to the optimization adjustment plan described in S6.

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