Substrate contamination detection method and coating system

Abstract

This application discloses a substrate contamination detection method and coating system, belonging to the field of semiconductor manufacturing technology. The method includes: providing process equipment, the process equipment including a coating chamber and a wafer loading chamber connected to the coating chamber; feeding a substrate into the wafer loading chamber; evacuating the wafer loading chamber to a preset pressure value and obtaining the evacuation time; if the evacuation time meets the set duration, feeding the substrate into the coating chamber; if the evacuation time does not meet the set duration, sending the substrate out of the process equipment. The evacuation time is used as the basis for determining whether the substrate carries moisture. When the evacuation time meets the set duration, the substrate is fed into the coating chamber; when it does not, the substrate is sent out of the process equipment. Moisture screening can be completed before the substrate enters the coating chamber, effectively preventing substrates carrying moisture from entering the coating chamber, and achieving accurate interception and traceability of contamination source substrates.

Description

Technical Field

[0001] This application relates to the field of semiconductor manufacturing technology, and in particular to a substrate contamination detection method and coating system. Background Technology

[0002] In advanced packaging multi-chamber clustered physical vapor deposition (PVD) production lines, large-area (≥510mm*515mm) rectangular substrates made of organic material are typically used as carriers. These substrates have a large surface area and the material itself has a certain degree of hygroscopicity. After wet cleaning, trace amounts of water stains easily remain on their surface and shallow layers. If a substrate carrying trace amounts of moisture is directly introduced into the main process chamber without effective screening, the residual moisture will rapidly sublimate or decompose under high vacuum, releasing water vapor. This causes a decrease in the chamber's reference vacuum, making it difficult to maintain the base vacuum within the process requirements. Continuing to perform pre-cleaning and seed layer deposition processes in this contaminated environment allows water molecules and their decomposition products to participate in or interfere with the film growth process, ultimately leading to a series of problems such as poor contact resistance and deterioration of the metal seed layer film quality, severely impacting device yield and reliability.

[0003] To address the aforementioned issues, traditional incoming material inspection methods, such as offline cleanliness testing and surface contact angle measurement, have limitations such as long testing cycles and the inability to achieve full online inspection. Furthermore, their test results lack a direct correlation with actual venting behavior under vacuum process conditions, making it difficult to meet the urgent need for high-throughput, online, and non-destructive screening in large-scale mass production.

[0004] Currently, the industry generally relies on post-contamination detection methods to address this issue. This involves detecting the vacuum level or residual gas composition within the process chamber after the substrate enters it to determine if it has been contaminated by moisture. However, this method has inherent and difficult-to-overcome technical drawbacks. Firstly, the detection timing is severely delayed. Anomalies are only detected after contaminants have entered the process chamber with the substrate and substantially contaminated the chamber's vacuum environment. By this time, water molecules may have already diffused and adhered to the inner walls of the chamber, the transport robot, and the surface of critical components such as the cooling platform, posing a risk of secondary cross-contamination and increasing the difficulty of chamber maintenance and restoration. Secondly, post-contamination detection cannot accurately intercept, trace, or isolate the contaminated substrate. It also struggles to effectively distinguish problematic substrates from normal ones on the production line. Furthermore, false alarms caused by vacuum fluctuations can lead to unnecessary production line shutdowns or substrate scrapping, severely restricting production efficiency and cost control. Summary of the Invention

[0005] This application aims to at least solve one of the technical problems existing in the prior art. To this end, in a first aspect, this application proposes a substrate contamination detection method that can solve the problem of substrate carrying moisture into the coating chamber.

[0006] Secondly, this application proposes a coating system for implementing the above-mentioned substrate contamination detection method.

[0007] The substrate contamination detection method according to the first aspect of this application includes: The equipment includes a coating chamber and a wafer loading chamber connected to the coating chamber. The substrate is fed into the wafer loading chamber; The wafer loading chamber is evacuated to a preset pressure value, and the evacuation time is obtained. If the vacuuming time meets the set duration, the substrate is sent into the coating chamber; if the vacuuming time does not meet the set duration, the substrate is sent out of the process equipment.

[0008] The substrate contamination detection method according to the embodiments of this application has at least the following beneficial effects: By setting up a wafer loading chamber and pre-loading the substrate into the chamber for vacuum testing, the vacuuming time is used as the criterion for determining whether the substrate carries moisture. If the vacuuming time meets the set duration, the substrate is sent into the coating chamber; otherwise, it is sent out of the process equipment. Since the wafer loading chamber and the coating chamber are relatively independent, the testing process is completed in the wafer loading chamber. Moisture screening can be completed before the substrate enters the coating chamber, effectively preventing substrates carrying moisture from entering the coating chamber. This eliminates the problem of decreased chamber vacuum and subsequent coating quality issues caused by moisture contamination at the source, achieving precise interception and traceability of contaminated substrates.

[0009] According to some embodiments of this application, the step of evacuating the wafer loading chamber to a preset pressure value and obtaining the evacuation time includes: The wafer loading chamber is evacuated to a first pressure value P1, and a first time value t1 is obtained; The loading chamber is evacuated from the second pressure value P2 to the third pressure value P3, and the second time value t2 is obtained.

[0010] According to some embodiments of this application, the step of sending the substrate into the coating chamber when the vacuuming time meets the set duration, and sending the substrate out of the process equipment when the vacuuming time does not meet the set duration, includes: Obtain the first time interval T1 and the second time interval T2; When the first time value t1 is greater than the first time interval T1 and the second time value t2 is greater than the second time interval T2, the substrate is sent out of the process equipment; otherwise, the substrate is sent into the coating chamber. Wherein, the first time interval T1 represents the theoretical time interval from atmospheric pressure to the first pressure value P1 when the substrate does not carry moisture, and the second time interval T2 represents the theoretical time interval from the second pressure value P2 to the third pressure value P3 when the substrate does not carry moisture.

[0011] According to some embodiments of this application, the first pressure value P1 is configured to a low vacuum, and the third pressure value P3 is configured to a high vacuum.

[0012] According to some embodiments of this application, evacuating the wafer loading chamber to a first pressure value P1 includes: evacuating the wafer loading chamber using a dry pump; The step of evacuating the wafer loading chamber from the second pressure value P2 to the third pressure value P3 includes: using a molecular pump to evacuate the wafer loading chamber.

[0013] According to some embodiments of this application, the second pressure value P2 is equal to the first pressure value P1.

[0014] According to some embodiments of this application, the step of sending the substrate into the coating chamber when the vacuuming time meets the set duration, and sending the substrate out of the process equipment when the vacuuming time does not meet the set duration, includes: During the process of evacuating the wafer loading chamber to a first pressure value P1 and obtaining a first time value t1, the first actual evacuation time t11 and a first time threshold t3 are obtained. If the first actual time t11 exceeds the first time threshold t3 and the actual pressure value of the wafer loading chamber is less than the first pressure value P1, the evacuation is stopped and the substrate is sent out of the process equipment.

[0015] According to some embodiments of this application, the step of sending the substrate into the coating chamber when the vacuuming time meets the set duration, and sending the substrate out of the process equipment when the vacuuming time does not meet the set duration, further includes: During the process of evacuating the wafer loading chamber from the second pressure value P2 to the third pressure value P3 and obtaining the second time value t2, the second actual evacuation time t22 and the second time threshold t4 are obtained. If the second actual time t22 exceeds the second time threshold t4 and the actual pressure value of the wafer loading chamber is less than the third pressure value P3, the evacuation is stopped and the substrate is sent out of the process equipment.

[0016] According to some embodiments of this application, the first time threshold t3 satisfies: t3 = 2 * T1, where T1 represents the theoretical time interval from atmospheric pressure to vacuum in the wafer loading chamber to the first pressure value P1 when the substrate does not carry moisture; and / or, The second time threshold t4 satisfies: t4 = 1.5 * T2, where T2 represents the theoretical time interval from the second pressure value P2 to the third pressure value P3 when the substrate does not carry moisture.

[0017] The coating system according to the second aspect of this application is used to implement the above-described substrate contamination detection method.

[0018] The coating system according to the embodiments of this application has at least the following beneficial effects: The coating system in this embodiment, by implementing the aforementioned substrate contamination detection method, can screen for moisture before the substrate enters the coating chamber, achieving pre-emptive detection and judgment. This avoids contamination of the coating chamber, which is beneficial for improving operational efficiency and ensuring equipment lifespan. Simultaneously, it can accurately intercept, trace, and isolate contaminated substrates, which plays a positive role in improving production efficiency and controlling production costs.

[0019] Additional aspects and advantages of this application will be set forth in part in the description which follows, and some of these additional aspects and advantages will become apparent from the description or may be learned by practice of this application. Attached Figure Description

[0020] The present application will be further described below with reference to the accompanying drawings and embodiments, wherein: Figure 1 This is a schematic flowchart of a substrate contamination detection method according to this application; Figure 2 This is a schematic diagram of the coating system of this application. Detailed Implementation

[0021] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0022] In the description of this application, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0023] In the description of this application, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0024] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0025] In the description of this application, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0026] Reference Figure 1 , Figure 2 The embodiments of this application propose a substrate contamination detection method, comprising the following steps: providing a process equipment, the process equipment including a coating chamber and a wafer loading chamber 102 connected to the coating chamber; feeding a substrate into the wafer loading chamber 102; evacuating the wafer loading chamber 102 to a preset pressure value and obtaining the evacuation time; if the evacuation time meets the set duration, feeding the substrate into the coating chamber; if the evacuation time does not meet the set duration, sending the substrate out of the process equipment.

[0027] In advanced packaging multi-chamber clustered physical vapor deposition production lines, large-area organic rectangular substrates are typically used as carriers. These substrates are prone to retaining trace amounts of water stains on their surface after wet cleaning. If a substrate carrying moisture directly enters the coating chamber, the residual moisture will rapidly sublimate or decompose under high vacuum, leading to a decrease in chamber vacuum and affecting coating quality. Furthermore, the residual water stains will evaporate more quickly in a vacuum due to pressure difference, acting as an additional "load" on the vacuuming speed and prolonging the vacuuming time. The detection method of this application creatively utilizes the wafer loading chamber 102 as a detection station. Before the substrate enters the coating chamber, the gas release characteristics of the substrate are evaluated by evacuating the wafer loading chamber 102 and monitoring the vacuuming time. Because the substrate carrying moisture continuously releases water molecules during the vacuuming process, the gas load in the wafer loading chamber 102 increases, and the time required to reach the same pressure is inevitably longer than for a dry substrate. Therefore, by comparing the measured vacuuming time with the set duration, it is possible to accurately determine whether the substrate carries excessive moisture, thereby achieving precise interception of contaminated substrates at the source.

[0028] Therefore, the substrate contamination detection method of this application embodiment can effectively prevent substrates carrying moisture from entering the coating chamber, thereby eliminating the decrease in chamber vacuum and subsequent coating quality problems caused by water vapor contamination from the source, and realizing accurate interception and traceability of contamination source substrates.

[0029] Meanwhile, by utilizing the vacuum in the wafer loading chamber 102, the impact on the vacuum level of the coating chamber can be reduced, thereby improving the overall process efficiency and process rhythm.

[0030] It is understood that the coating system of this application embodiment has various specific implementations. In some embodiments, the coating system is configured as a physical vapor deposition apparatus for depositing metal seed layers in large-size board-level advanced packaging. As an exemplary structural form of the apparatus, it is designed as a leaf-shaped structure, suitable for processing large-area rectangular substrates with a size of not less than 510mm × 515mm. This leaf-shaped structure, by setting multiple functional chambers and arranging them in a cluster around a central transfer chamber 100, can realize the sequential transfer and continuous process processing of substrates, with high production efficiency and process consistency. In this exemplary structure, a transfer chamber 100 is set at the central position of the coating system, and a vacuum robot is provided inside the transfer chamber 100. The vacuum robot is used to transfer substrates between the various chambers. This layout of the central transfer chamber 100 and the vacuum robot enables rapid and clean transfer of substrates between multiple chambers, avoiding exposure of the substrate to the atmospheric environment and ensuring the continuity and stability of the process.

[0031] Reference Figure 2As shown, based on the above embodiment, multiple functional chambers can be configured around the transfer cavity 100. Specifically, the transfer cavity 100 can be surrounded by a physical vapor deposition (PVD) copper chamber 106, a PVD titanium chamber 105, a pre-cleaning chamber 104, a wafer entry chamber 102, a wafer exit chamber 101, and a degassing chamber 103. The PVD copper chamber 106 is used to deposit a copper seed layer on the substrate surface; the PVD titanium chamber 105 is used to deposit a titanium seed layer or a titanium barrier layer on the substrate surface; the pre-cleaning chamber 104 is used to perform ion bombardment or sputtering cleaning on the substrate surface before deposition to remove surface contaminants and oxide layers; the wafer entry chamber 102 serves as a transition chamber for the substrate to enter the vacuum system from the outside; the wafer exit chamber 101 serves as a transition chamber for the substrate to be transferred from the vacuum system to the outside; and the degassing chamber 103 is used to perform heating and degassing treatment on the substrate before coating to remove gas molecules adsorbed inside the substrate. Through the coordinated operation of the aforementioned multiple functional chambers, this coating system can sequentially complete the entire process steps of substrate degassing, pre-cleaning, titanium layer deposition, and copper layer deposition in a vacuum environment, thereby meeting the high-quality preparation requirements of metal seed layers in the advanced packaging field.

[0032] As the first stage for substrates entering the vacuum system, the structure and configuration of the wafer entry chamber 102 significantly impact the implementation of the detection method. In some embodiments, the wafer entry chamber 102 is connected to a dry pump for rough vacuuming and a molecular pump or cold pump for high vacuuming. The dry pump features high pumping speed and is suitable for rapid evacuation from atmospheric pressure to the low vacuum range, quickly removing a large amount of gas from the wafer entry chamber 102, shortening the substrate's residence time within the chamber, and improving production line efficiency. The molecular pump is suitable for fine evacuation from the low vacuum to the high vacuum range, evacuating the wafer entry chamber 102 to a high vacuum level, providing a pressure transition for the subsequent substrate entry into the coating chamber. The cold pump adsorbs gas molecules through low-temperature condensation, achieving a higher ultimate vacuum and a cleaner vacuum environment. Through the combined configuration of the dry pump and the molecular pump or cold pump, the wafer entry chamber 102 achieves a good balance between high pumping speed and high vacuum, satisfying both the time requirements for rapid detection and the vacuum requirements of subsequent processes.

[0033] Based on the structural foundation of the process equipment in the above embodiments, in some embodiments, the detection method includes the following detailed steps. First, the substrate to be tested is introduced into the wafer loading chamber 102, and the chamber door of the wafer loading chamber 102 is closed to form a closed vacuum space. Subsequently, a dry pump is started to evacuate the wafer loading chamber 102, and the vacuum level inside the wafer loading chamber 102 is monitored in real time. During the evacuation process, the first evacuation time is recorded as the vacuum level in the wafer loading chamber 102 decreases from atmospheric pressure to a first preset pressure threshold. When the vacuum level reaches the first preset pressure threshold, a molecular pump is started to continue evacuating to a second preset pressure threshold, and the second evacuation time is recorded as the vacuum level decreases from the first preset pressure threshold to the second preset pressure threshold. After obtaining the first evacuation time and the second evacuation time, the first evacuation time is compared with a first reference time interval, and the second evacuation time is compared with a second reference time interval. If the first evacuation time is greater than the upper limit of the first reference time interval, and the second evacuation time is greater than the upper limit of the second reference time interval, it is determined that there are abnormal volatiles or residues on the surface of the substrate. For substrates identified as having abnormal volatiles, the automatic conveying system directly discharges them from the wafer loading chamber 102 and sends them out of the process equipment, preventing them from entering the subsequent coating chamber. At the same time, an engineer intervention signal is triggered for manual confirmation and cause analysis.

[0034] In the above detection process, the specific values ​​of the first and second preset pressure thresholds have a significant impact on the detection sensitivity and efficiency. In some embodiments, the first preset pressure threshold is preferably 20 Pa, and the second preset pressure threshold is preferably 5E-4 Pa. 20 Pa is chosen as the endpoint pressure of the low vacuum stage because this pressure value is at the end of the high-efficiency pumping range of the dry pump. At this pressure, the competition between the rate at which water molecules desorb from the substrate surface and enter the gas phase and the discharge rate of the pumping system is most sensitive, effectively reflecting the residual moisture status on the substrate surface. 5E-4 Pa is chosen as the endpoint pressure of the high vacuum stage because this pressure value is close to the ultimate vacuum range in which the molecular pump can operate stably. At this pressure, the partial pressure ratio of water molecules in the residual gas can be significantly amplified, thereby improving the detection sensitivity.

[0035] Understandably, the physical principle behind the above detection method is as follows: Water stains remaining on the substrate surface will evaporate more rapidly in a vacuum environment due to pressure difference. In the low vacuum stage, i.e., during the process of pumping from atmospheric pressure to 20 Pa, the evaporation rate of water is mainly limited by mass transfer processes, i.e., the rate at which water molecules diffuse from the substrate surface to the bulk gas phase and the rate at which they are removed by the pumping system. When water stains are present on the substrate surface, the continuously evaporating water molecules constitute an additional "gas load" on the dry pumping speed, slowing down the pressure drop rate within the wafer loading chamber 102, resulting in a significantly longer first pumping time relative to the dry substrate. In the high vacuum stage, i.e., during the process of pumping from 20 Pa to 5E-4 Pa, the gas in the wafer loading chamber 102 is already very rarefied, at which point the gas composition has a significant impact on the pumping rate. The molecular pump exhibits different pumping speeds for different gas molecules; its pumping speed for water molecules (molecular weight approximately 18) is significantly lower than its pumping speed for nitrogen (molecular weight approximately 28) and oxygen (molecular weight approximately 32). Therefore, when residual water stains remain on the substrate surface and water vapor is continuously released, the partial pressure ratio of water vapor in the wafer feed chamber 102 increases, and the effective pumping rate of the molecular pump decreases, resulting in a significantly longer second pumping time relative to the dried substrate. Based on the above physical principle, by monitoring the pumping time in both the low vacuum and high vacuum stages and comparing the measured time with the reference time of the dried substrate, contaminated substrates carrying residual water stains can be accurately and sensitively identified.

[0036] In some embodiments, in order to more comprehensively characterize the outgassing behavior of the substrate under different vacuum levels, the steps of evacuating the wafer inlet chamber 102 to a preset pressure value and obtaining the evacuation time are further refined as follows: The wafer loading chamber 102 is evacuated to a first pressure value P1, and a first time value t1 is obtained. The wafer loading chamber 102 is then evacuated from a second pressure value P2 to a third pressure value P3, and a second time value t2 is obtained. By timing the low-vacuum and high-vacuum stages separately, two sets of independent detection data can be obtained. The low-vacuum stage mainly reflects the rapid release characteristics of moisture adsorbed on the substrate surface, while the high-vacuum stage more sensitively reflects the slow release behavior of moisture absorbed by the shallow surface layer of the substrate. The two sets of data corroborate each other, providing a richer and more reliable information basis for subsequent judgment, effectively improving the accuracy and reliability of the detection.

[0037] It is worth noting that in some embodiments, the second-stage vacuum level can be obtained in various ways: either the vacuum can be continuously pumped to the third pressure level P3 after reaching the first pressure value P1, or the second stage can be entered after the first pressure value P1 has been kept stable for a certain period of time. Since setting the second pressure value P2 to be equal to the first pressure value P1 has the advantages of continuous process and seamless data connection, it can be preferred.

[0038] Furthermore, in some embodiments, the above determination step specifically includes: Obtain the first time interval T1 and the second time interval T2; when the first time value t1 is greater than the first time interval T1 and the second time value t2 is greater than the second time interval T2, send the substrate out of the process equipment; otherwise, send the substrate into the coating chamber.

[0039] The first time interval T1 represents the theoretical time interval for the wafer loading chamber 102 to be evacuated from atmospheric pressure to the first pressure value P1 when the substrate is free of moisture. The second time interval T2 represents the theoretical time interval for the wafer loading chamber 102 to be evacuated from the second pressure value P2 to the third pressure value P3 when the substrate is free of moisture. By comparing the measured times of the two stages with the corresponding theoretical intervals, and using a dual-condition comprehensive judgment—only when the time of both stages exceeds the upper limit of their respective theoretical intervals is it judged as unqualified—false judgments caused by fluctuations in data from a single stage (such as instantaneous changes in pump performance, the influence of ambient temperature and humidity, etc.) can be effectively avoided. This significantly improves the judgment accuracy, reduces the false alarm rate, and avoids unnecessary substrate scrapping and production stoppages caused by false judgments.

[0040] Furthermore, the use of a first time interval T1 and a second time interval T2 is also to avoid misjudgments caused by time fluctuations.

[0041] It is conceivable that the pressure setting during the vacuuming process has a significant impact on detection efficiency and accuracy. In some embodiments, the first pressure value P1 is configured for a low vacuum level, and the third pressure value P3 is configured for a high vacuum level. By setting two detection stages corresponding to the low vacuum and high vacuum ranges respectively, complementary detection can be performed using the differentiated characteristics of water analysis under different vacuum levels, making the detection results more comprehensive and accurate. In the low vacuum stage, the release of water molecules is mainly controlled by the mass transfer process, with a larger time constant, which can reflect the total amount of residual moisture on the substrate surface. In the high vacuum stage, the partial pressure ratio of water molecules in the residual gas is amplified, resulting in higher detection sensitivity and the ability to reflect the residual moisture in the shallow surface layer and microporous structure of the substrate. The two stages complement each other, achieving a comprehensive assessment of the residual moisture status of the substrate. At the same time, the vacuum level created by the detection is used to reduce the impact on the vacuum level of the coating chamber, eliminating the need for complete vacuum breaking in the coating chamber.

[0042] Furthermore, to achieve rapid switching and precise control between different vacuum levels, in some embodiments, a dry pump is used to evacuate the wafer loading chamber 102 to a first pressure value P1, and a molecular pump is used to evacuate the wafer loading chamber 102 from a second pressure value P2 to a third pressure value P3. The dry pump has the characteristics of high pumping speed and suitability for rapid evacuation from atmospheric pressure to low vacuum, enabling it to quickly remove a large amount of gas from the wafer loading chamber 102 and shorten the detection cycle. The molecular pump is suitable for fine evacuation from low vacuum to high vacuum, capable of evacuating the chamber to the high vacuum level required for the process. The combined use of the dry pump and the molecular pump ensures both evacuation efficiency and meets the accuracy requirements of different stages, optimizing the time cost of the detection process.

[0043] In a preferred embodiment, the second pressure value P2 is equal to the first pressure value P1. That is, the end pressure of the first stage is the same as the starting pressure of the second stage. This achieves seamless connection between the two detection stages in terms of pressure, avoiding detection blind spots caused by pressure jumps, making the entire vacuuming process continuous and smooth, and ensuring a unified benchmark for the two sets of time data, making them more comparable and valuable for reference. Specifically, once the vacuum level in the wafer entry chamber 102 is pumped to the first pressure value P1 by the dry pump, the molecular pump is immediately started to continue pumping gas, starting from the same pressure value and progressing to the third pressure value P3, without any waiting or pressure adjustment. This continuous pumping method not only simplifies the detection process and reduces the complexity of the control logic, but also ensures that the gas composition in the wafer entry chamber 102 at the end of the low vacuum stage is consistent with the gas composition at the beginning of the high vacuum stage. The time data of the two stages can more accurately reflect the variation of substrate outgassing behavior in different pressure ranges.

[0044] In some embodiments, considering that when there is a large amount of residual water on the substrate surface, the vacuuming time may be extremely long, severely affecting production line efficiency, the detection method also includes an early termination logic. Specifically, during the process of evacuating the wafer loading chamber 102 to a first pressure value P1 and obtaining a first time value t1, the first actual vacuuming time t11 and a first time threshold t3 are obtained. If the first actual time t11 exceeds the first time threshold t3 and the actual pressure value of the wafer loading chamber 102 is less than the first pressure value P1, the vacuuming is stopped, and the substrate is sent out of the process equipment. That is, if it is found in the roughing stage that the actual evacuation time has exceeded the set threshold but the pressure is still not up to standard, there is no need to continue waiting; the substrate is directly determined to be unqualified and sent out. This design can avoid unlimited continuous evacuation in the case of extremely severe contamination, significantly shorten the detection time of abnormal substrates, and prevent the production cycle of the entire production line from being disrupted due to a few severely contaminated substrates.

[0045] Furthermore, a similar early termination logic is implemented during the high vacuum phase. Specifically, during the process of evacuating the wafer loading chamber 102 from the second pressure value P2 to the third pressure value P3 and obtaining the second time value t2, the second actual evacuation time t22 and the second time threshold t4 are obtained. If the second actual time t22 exceeds the second time threshold t4 and the actual pressure value of the wafer loading chamber 102 is less than the third pressure value P3, the evacuation is stopped, and the substrate is sent out of the process equipment. By setting a time threshold as a termination condition during the high vacuum phase, the detection efficiency can be further optimized while ensuring detection accuracy, and the service life of the molecular pump can be avoided due to prolonged full-load operation caused by a few severely contaminated substrates. At the same time, the introduction of early termination logic also reduces energy consumption and equipment wear, resulting in significant economic benefits.

[0046] In some embodiments, the first time threshold satisfies: t3 = 2 * T1, where T1 represents the theoretical time interval for the wafer loading chamber 102 to be evacuated from atmospheric pressure to the first pressure value P1 when the substrate does not carry moisture; the second time threshold satisfies: t4 = 1.5 * T2, where T2 represents the theoretical time interval for the wafer loading chamber 102 to be evacuated from the second pressure value P2 to the third pressure value P3 when the substrate does not carry moisture. Establishing a clear numerical correlation between the time threshold and the theoretical time interval provides a scientific theoretical basis for the threshold setting. Using a threshold of 2 times the theoretical time in the low vacuum stage is to leave sufficient detection window for the rapid release of surface-adsorbed moisture, while avoiding misjudgment due to occasional instantaneous outgassing pulses in the roughing stage. Using a threshold of 1.5 times the theoretical time in the high vacuum stage is to balance detection accuracy and efficiency based on the characteristic that the outgassing behavior is more sensitive under high vacuum, because the influence of water vapor on the pumping speed of the molecular pump is more significant in the high vacuum stage, and the time extension is more obvious than in the low vacuum stage, so the threshold multiple can be appropriately reduced. This threshold design achieves a good balance between rapid identification of contaminated substrates and thorough detection of slightly contaminated substrates.

[0047] The following describes a detection method according to one specific embodiment of this application. (Refer to...) Figure 2As shown, in this embodiment, the coating system is a leaf-type physical vapor deposition (PVD) apparatus used for large-size board-level advanced packaging metal seed layer deposition, suitable for rectangular substrates with dimensions not less than 510mm × 515mm. This PVD apparatus has a multi-chamber cluster structure, with a central transfer chamber 100. A vacuum manipulator is installed inside the transfer chamber 100 to transfer the substrate between the chambers. Surrounding the transfer chamber 100 are a copper PVD chamber 106, a titanium PVD chamber 105, a pre-cleaning chamber 104, a wafer entry chamber 102, a wafer exit chamber 101, and a degassing chamber 103. The wafer entry chamber 102 is the aforementioned wafer entry chamber 102, with a volume of approximately 150L, ​​equipped with a dry pump with a pumping speed of 100L / s and a molecular pump with a pumping speed of 1800L / s.

[0048] During testing, the substrate is first introduced into the wafer loading chamber 102. After the chamber door is closed, the dry pump is started to evacuate the wafer loading chamber 102. As the vacuum level is evacuated from atmospheric pressure to the first pressure value P1, the system continuously monitors the actual evacuation time. For a dry substrate, the theoretical upper limit for evacuation from atmospheric pressure to 20 Pa is 22 seconds. If the actual evacuation time reaches 44 seconds (twice the theoretical upper limit) and the pressure inside the wafer loading chamber 102 has not yet dropped to 20 Pa, the substrate is determined to carry excessive moisture. Vacuuming is immediately stopped, the substrate is removed from the process equipment, and an engineer alarm is triggered.

[0049] If the dry pump operation phase is successful, meaning the actual evacuation time is less than twice the theoretical maximum, and the pressure reaches 20 Pa, the molecular pump is activated to continue evacuating the wafer loading chamber 102 from 20 Pa to a high vacuum of 5E-4 Pa. For the dried substrate, the theoretical maximum time for evacuation from 20 Pa to 5E-4 Pa is 50 seconds. If the actual evacuation time reaches 75 seconds (1.5 times the theoretical maximum) and the pressure has not yet dropped to 5E-4 Pa, the substrate is deemed unqualified, evacuation is stopped, and the substrate is removed. If evacuation is completed within the specified time for both phases, the substrate is deemed qualified, and a vacuum robot transfers the substrate from the wafer loading chamber 102 to the coating chamber for subsequent processes.

[0050] Based on the above method, during the testing of a certain batch of substrates, the time taken to pump from atmospheric pressure to 20 Pa was 26 seconds, exceeding the theoretical limit of 22 seconds by 4 seconds; the time taken to pump from 20 Pa to 5E-4 Pa using a molecular pump was 58 seconds, exceeding the theoretical limit of 50 seconds by 8 seconds. Since both stages exceeded their respective theoretical ranges, the system determined that the substrate was contaminated. The automatic transfer system moved it to the wafer exit chamber 101 and triggered an engineer's alarm. Offline testing by the engineer confirmed the presence of invisible residual water stains on the substrate's edge area, fully validating the effectiveness and sensitivity of the detection method proposed in this application.

[0051] It is understandable that in actual production line operation, the amount of residual water stains on the substrate surface is not constant, but rather varies within a certain range due to factors such as fluctuations in the cleaning process, substrate storage time, and environmental conditions. For slightly contaminated substrates, the vacuuming time may only slightly exceed the baseline range. In this case, the dual-condition comprehensive judgment logic can effectively identify and intercept the contamination, while avoiding misjudgments caused by exceeding the critical limit in a single stage. For severely contaminated substrates, the early termination logic can intervene in a timely manner to avoid prolonged ineffective vacuuming. Therefore, the detection method of this application embodiment has good adaptability and identification capability for substrates with different degrees of contamination.

[0052] Furthermore, in the specific implementation of the detection method, there are multiple implementation schemes for obtaining the reference time interval. In some embodiments, the reference time interval can be obtained through theoretical calculation, that is, based on the volume of the wafer loading chamber 102, the pumping speed curve of the dry pump, the pumping speed curve of the molecular pump, and the pumping characteristics under different gas compositions, combined with the gas release model of the substrate in the wafer loading chamber 102, the theoretical gas release time and reasonable fluctuation range of the dried substrate in each pressure range are calculated.

[0053] In other embodiments, the reference time interval can be obtained through experimental calibration. This involves performing repeated tests under identical conditions using a known dry substrate, statistically analyzing the distribution range of evacuation times, and using this as a baseline. These two methods can mutually verify and complement each other to obtain a more accurate reference interval. In actual production line applications, the reference time interval can also be periodically calibrated and updated based on changes in equipment status. For example, the reference interval can be recalibrated after maintenance of the dry pump or molecular pump to ensure that the testing standard matches the actual performance of the equipment.

[0054] In some embodiments, the execution and judgment results of the detection method can be integrated with the automated control system of the production line. When the substrate is judged to be qualified, the automated control system generates an entry permission signal. Based on this signal, the vacuum robot transfers the substrate from the loading chamber 102 to the transfer chamber 100, and sequentially feeds it into the degassing chamber 103, the pre-cleaning chamber 104, the physical vapor deposition titanium chamber 105, and the physical vapor deposition copper chamber 106 for corresponding processing according to the preset process route. When the substrate is judged to be unqualified, the automated control system generates an interception signal. The vacuum robot directly transfers the substrate from the loading chamber 102 to the exit chamber 101, triggering an audible and visual alarm or sending an alarm message to the engineer's terminal. Simultaneously, the automated control system can also record and store detection data, including but not limited to substrate number, detection time, two-stage evacuation time, judgment result, and other key information, for subsequent data traceability and quality analysis. This deep integration with the production line automation system enables the detection method to operate online and automatically without manual intervention, achieving high-throughput screening capabilities.

[0055] In some embodiments, the detection method also incorporates substrate identification information for management. Specifically, before the substrate enters the wafer loading chamber 102, its identification information is recorded in the system via barcode scanning or RFID. After detection, the judgment result is associated with the substrate's identification information and stored in the production execution system. When a substrate is determined to be unqualified, the production execution system can automatically record the substrate's anomaly information and generate a summary report of contaminated substrates in subsequent statistical reports, providing data support for engineers to analyze the stability of the cleaning process and optimize cleaning parameters. Through this information-based management approach, the detection method not only achieves substrate screening and interception but also provides valuable feedback information for process improvement.

[0056] It is conceivable that the detection method of this application is not only applicable to detecting water stains on the substrate surface, but also to detecting other types of volatile residues or contaminants. In wet cleaning processes, in addition to water stains, trace amounts of organic solvents, surfactants, or other chemical reagents may remain on the substrate surface. These residues will also volatilize or decompose under vacuum, releasing additional gas molecules and prolonging the vacuuming time. Therefore, the detection method of this application has broad applicability, not limited to moisture detection, but also extended to the online screening of other volatile contaminants. When the target contaminant is something other than water stains, only the detection parameters such as the first pressure value, the second pressure value, and the reference time interval need to be adjusted according to the volatility characteristics of the contaminant, without requiring substantial modifications to the detection method and equipment.

[0057] Furthermore, in some embodiments, the detection results of the testing method are also used for grading. Specifically, in addition to the two grading results of pass and fail, a "caution" level is also set. When only one stage of the two-stage test time exceeds the reference range, or when the deviation of both stages from the reference range is small but does not meet the judgment criteria, the system can determine that the substrate is at the "caution" level. For substrates at the "caution" level, the system still allows them to enter the coating chamber for processing, but at the same time issues a warning message to the engineer, suggesting that the product corresponding to the substrate be closely monitored in subsequent processes. This grading method increases the flexibility of the detection system, and can reduce unnecessary substrate scrapping and lower production costs while ensuring product quality.

[0058] In some embodiments, the wafer loading chamber 102 is also equipped with a heating device. Before or during vacuum testing, the substrate can be moderately heated by the heating device to accelerate the evaporation of residual moisture and shorten the vacuuming time. However, heating also alters the temperature state of the substrate, potentially affecting subsequent processes. Therefore, whether to use heating assistance requires comprehensive evaluation based on specific process requirements. When heating assistance is used, the reference time interval of the testing method should be calibrated under the same temperature conditions as the testing conditions to ensure the accuracy of the test results.

[0059] This application also proposes a coating system for implementing the above-described substrate contamination detection method. Since the coating system of this embodiment employs the detection method of the above-described embodiments, this embodiment possesses all the beneficial effects of the above-described embodiments.

[0060] In some embodiments, the coating system is configured as a physical vapor deposition apparatus for depositing metal seed layers in large-size board-level advanced packaging. As an exemplary structural form of the apparatus, it is designed as a leaf-shaped structure, suitable for processing large-area rectangular substrates with dimensions not less than 510mm × 515mm. This leaf-shaped structure, by setting multiple functional chambers clustered around a central transfer chamber 100, enables sequential transfer and continuous process processing of substrates, resulting in high production efficiency and process consistency. In this exemplary structure, a transfer chamber 100 is located at the center of the coating system, and a vacuum robot is installed inside the transfer chamber 100 for transferring substrates between the chambers. This layout of the central transfer chamber 100 and the vacuum robot enables rapid and clean transfer of substrates between multiple chambers, avoiding exposure of the substrates to the atmospheric environment and ensuring process continuity and stability.

[0061] Reference Figure 2As shown, based on the above embodiment, multiple functional chambers can be configured around the transfer cavity 100. Specifically, the transfer cavity 100 can be surrounded by a physical vapor deposition (PVD) copper chamber 106, a PVD titanium chamber 105, a pre-cleaning chamber 104, a wafer entry chamber 102, a wafer exit chamber 101, and a degassing chamber 103. The PVD copper chamber 106 is used to deposit a copper seed layer on the substrate surface; the PVD titanium chamber 105 is used to deposit a titanium seed layer or a titanium barrier layer on the substrate surface; the pre-cleaning chamber 104 is used to perform ion bombardment or sputtering cleaning on the substrate surface before deposition to remove surface contaminants and oxide layers; the wafer entry chamber 102 serves as a transition chamber for the substrate to enter the vacuum system from the outside; the wafer exit chamber 101 serves as a transition chamber for the substrate to be transferred from the vacuum system to the outside; and the degassing chamber 103 is used to perform heating and degassing treatment on the substrate before coating to remove gas molecules adsorbed inside the substrate. Through the coordinated operation of the aforementioned multiple functional chambers, this coating system can sequentially complete the entire process steps of substrate degassing, pre-cleaning, titanium layer deposition, and copper layer deposition in a vacuum environment, thereby meeting the high-quality preparation requirements of metal seed layers in the advanced packaging field.

[0062] As the first stage for substrates entering the vacuum system, the structure and configuration of the wafer entry chamber 102 significantly impact the implementation of the detection method. In some embodiments, the wafer entry chamber 102 is connected to a dry pump for rough vacuuming and a molecular pump or cold pump for high vacuuming. The dry pump features high pumping speed and is suitable for rapid evacuation from atmospheric pressure to the low vacuum range, quickly removing a large amount of gas from the wafer entry chamber 102, shortening the substrate's residence time within the chamber, and improving production line efficiency. The molecular pump is suitable for fine evacuation from the low vacuum to the high vacuum range, evacuating the wafer entry chamber 102 to a high vacuum level, providing a pressure transition for the subsequent substrate entry into the coating chamber. The cold pump adsorbs gas molecules through low-temperature condensation, achieving a higher ultimate vacuum and a cleaner vacuum environment. Through the combined configuration of the dry pump and the molecular pump or cold pump, the wafer entry chamber 102 achieves a good balance between high pumping speed and high vacuum, satisfying both the time requirements for rapid detection and the vacuum requirements of subsequent processes.

[0063] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application. Furthermore, unless otherwise specified, the embodiments and features described in the embodiments of this application can be combined with each other.

Claims

1. A method for detecting substrate contamination, characterized in that, include: The equipment includes a coating chamber and a wafer loading chamber connected to the coating chamber. The substrate is fed into the wafer loading chamber; The wafer loading chamber is evacuated to a preset pressure value, and the evacuation time is obtained. If the vacuuming time meets the set duration, the substrate is sent into the coating chamber; if the vacuuming time does not meet the set duration, the substrate is sent out of the process equipment.

2. The substrate contamination detection method according to claim 1, characterized in that, The step of evacuating the wafer loading chamber to a preset pressure value and obtaining the evacuation time includes: The wafer loading chamber is evacuated to a first pressure value P1, and a first time value t1 is obtained; The loading chamber is evacuated from the second pressure value P2 to the third pressure value P3, and the second time value t2 is obtained.

3. The substrate contamination detection method according to claim 2, characterized in that, The step of sending the substrate into the coating chamber when the vacuuming time meets the set duration, and sending the substrate out of the process equipment when the vacuuming time does not meet the set duration, includes: Obtain the first time interval T1 and the second time interval T2; When the first time value t1 is greater than the first time interval T1 and the second time value t2 is greater than the second time interval T2, the substrate is sent out of the process equipment; otherwise, the substrate is sent into the coating chamber. Wherein, the first time interval T1 represents the theoretical time interval from atmospheric pressure to the first pressure value P1 when the substrate does not carry moisture, and the second time interval T2 represents the theoretical time interval from the second pressure value P2 to the third pressure value P3 when the substrate does not carry moisture.

4. The substrate contamination detection method according to claim 2, characterized in that, The first pressure value P1 is configured for low vacuum, and the third pressure value P3 is configured for high vacuum.

5. The substrate contamination detection method according to claim 4, characterized in that, The step of evacuating the wafer loading chamber to a first pressure value P1 includes: using a dry pump to evacuate the wafer loading chamber; The step of evacuating the wafer loading chamber from the second pressure value P2 to the third pressure value P3 includes: using a molecular pump to evacuate the wafer loading chamber.

6. The substrate contamination detection method according to claim 2, characterized in that, The second pressure value P2 is equal to the first pressure value P1.

7. The substrate contamination detection method according to claim 2, characterized in that, The step of sending the substrate into the coating chamber when the vacuuming time meets the set duration, and sending the substrate out of the process equipment when the vacuuming time does not meet the set duration, includes: During the process of evacuating the wafer loading chamber to a first pressure value P1 and obtaining a first time value t1, the first actual evacuation time t11 and a first time threshold t3 are obtained. If the first actual time t11 exceeds the first time threshold t3 and the actual pressure value of the wafer loading chamber is less than the first pressure value P1, the evacuation is stopped and the substrate is sent out of the process equipment.

8. The substrate contamination detection method according to claim 7, characterized in that, The step of sending the substrate into the coating chamber when the vacuuming time meets the set duration, and sending the substrate out of the process equipment when the vacuuming time does not meet the set duration, further includes: During the process of evacuating the wafer loading chamber from the second pressure value P2 to the third pressure value P3 and obtaining the second time value t2, the second actual evacuation time t22 and the second time threshold t4 are obtained. If the second actual time t22 exceeds the second time threshold t4 and the actual pressure value of the wafer loading chamber is less than the third pressure value P3, the evacuation is stopped and the substrate is sent out of the process equipment.

9. The substrate contamination detection method according to claim 8, characterized in that, The first time threshold t3 satisfies: t3 = 2 * T1, where T1 represents the theoretical time interval from atmospheric pressure to the first pressure value P1 when the substrate does not carry moisture; and / or, The second time threshold t4 satisfies: t4 = 1.5 * T2, where T2 represents the theoretical time interval from the second pressure value P2 to the third pressure value P3 when the substrate does not carry moisture.

10. A coating system, characterized in that, Used to implement the substrate contamination detection method according to any one of claims 1 to 9.

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