A post-cmp wafer thickness measurement apparatus and method, cleaning chamber

Abstract

The present application relates to a kind of CMP process wafer thickness measurement device and method, cleaning chamber, belong to the technical field of semiconductor manufacturing process, solve the wafer surface film thickness measurement in prior art needs separate step, process step waste, low production efficiency;It can cause the re-falling and attachment of particle;Equipment space occupies big, equipment manufacturing cost problem of rising.The CMP process wafer thickness measurement device of the present application, including wafer thickness measurement equipment;Wafer thickness measurement equipment is set in cleaning chamber, and located above the dry gas injection port above cleaning agent pool;Wafer thickness measurement equipment is used to measure wafer thickness in the rising process after wafer cleaning is completed.It is realized to measure the CMP effect while being dried in Malangoni.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing process technology, and in particular to a wafer thickness measurement device after the CMP process, a CMP effect measurement device and method based on Marangoni drying, and a cleaning chamber. Background Technology

[0002] CMP (Chemical Mechanical Polishing) is a process that uses mechanical force combined with chemical assistance to planarize a wafer. To protect the patterns on the wafer and remove unevenness caused by etching, film planarization is necessary for subsequent photolithography and other processes. Before CMP, various deposition films with different functions and thicknesses are typically generated through multiple deposition processes. Therefore, CMP consists of multiple polishing processes, with different degrees of polishing applied at different stages to selectively protect the patterns. Monitoring the CMP polishing process and measuring the CMP effect requires determining the film thickness on the wafer surface after CMP. However, during the polishing process, the high-speed rotation of the polishing head and bearing disk can easily cause polishing fluid to splash out or form a mist. This splashed polishing fluid can easily accumulate and crystallize. If these crystals fall off or remain on the wafer surface, it becomes impossible to accurately measure the film thickness on the wafer surface after polishing. Therefore, after CMP, the wafer must be cleaned to accurately measure the film thickness on the wafer surface.

[0003] In existing technologies, measuring the CMP effect requires transferring the wafer to a thickness gauge in the measurement chamber after cleaning to measure the thickness of the thin film on the wafer surface. This method presents several problems. In multi-CMP processes, multiple CMP operations are required, with the wafer being cleaned and then measured in the measurement chamber after each CMP cycle, resulting in numerous repetitive steps and low production efficiency. Furthermore, the transfer of the wafer to the measurement chamber may introduce solid particles that settle on the wafer surface, compromising measurement accuracy and potentially causing surface damage. The transfer of the wafer from the cleaning unit to the measurement chamber and then from the thickness gauge platform to the next process step requires multiple gripping operations by a robotic arm. These gripping operations apply physical force, increasing the risk of wafer breakage with each subsequent gripping operation. Additionally, the entire process necessitates a separate measurement chamber for measuring the wafer surface thickness, resulting in significant space requirements and increased manufacturing costs. Summary of the Invention

[0004] Based on the above analysis, the present invention aims to provide a wafer thickness measurement device and method and a cleaning chamber after the CMP process, which can solve at least one of the following technical problems: (1) The wafer surface film thickness measurement requires a separate step, which wastes process steps and has low production efficiency; (2) During the process of transferring the wafer to the measurement chamber, particles may fall and adhere again, reducing measurement accuracy, posing a risk of wafer scratches, and affecting subsequent production processes; (3) When the wafer is transferred to the thickness gauge platform and then enters the subsequent process, it needs to withstand the force generated by the multiple gripping of the robot arm, which increases the risk of wafer breakage; (4) The entire manufacturing process requires a separate measurement chamber to measure the wafer surface film thickness, which occupies a large space and increases the equipment manufacturing cost.

[0005] On one hand, the present invention provides a wafer thickness measurement device after CMP process, including wafer thickness measurement equipment;

[0006] The wafer thickness measuring device is installed inside the cleaning chamber and is located above the dry gas injection port above the cleaning agent tank.

[0007] The wafer thickness measuring device is used to measure the wafer thickness during the rising process after wafer cleaning.

[0008] Furthermore, the wafer thickness measurement device includes an optical transmitter and an optical receiver;

[0009] Both the optical transmitter and the optical receiver are located inside the cleaning chamber and above the dry gas injection port above the cleaning agent pool.

[0010] The optical emitter is used to emit detection light;

[0011] The optical receiver is used to receive the detection light after it has been reflected and refracted by the wafer surface.

[0012] Furthermore, the optical transmitter is a laser transmitter, and the optical receiver is a laser receiver.

[0013] Furthermore, the optical transmitter, optical receiver, and dry gas injection port are activated simultaneously.

[0014] Furthermore, the wafer rise direction is parallel to the wafer surface, and the optical transmitter and optical receiver are 1-4 cm away from the wafer surface.

[0015] Furthermore, the optical transmitter and optical receiver are mounted at a position no higher than the highest position of the rising wafer.

[0016] Furthermore, the optical transmitter is a linear optical transmitter, and the optical receiver is a linear optical receiver.

[0017] Furthermore, the linear optical emitter and the linear optical receiver are placed horizontally, the detection width d1 of the detection light of the linear optical emitter is not less than the wafer diameter d, and the detection width d2 of the detection light of the linear optical receiver is not less than 1.1 times d1.

[0018] Furthermore, the drying process is Marangoni drying, and the wafer is raised under the action of a lifting mechanism after the cleaning is completed.

[0019] On one hand, the present invention provides a method for measuring wafer thickness after a CMP process, comprising:

[0020] After the CMP process, the wafer enters the cleaning chamber;

[0021] After the wafer is cleaned in the cleaning agent pool in the cleaning chamber, it is lifted by the lifting device.

[0022] As the wafer begins to rise, the drying gas nozzle begins to inject Marangoni drying gas;

[0023] When the highest point of the wafer is aligned with the dry gas nozzle, the wafer thickness measurement device above the dry gas nozzle starts working to detect the thickness of the rising wafer in real time.

[0024] Furthermore, the drying gas injection port is disposed on the injection rod, and the injected gas is a mixture of high-temperature vapor of isopropanol and nitrogen, with a volume ratio of isopropanol to nitrogen of 1:4 to 4:1.

[0025] On the other hand, the present invention provides a wafer cleaning chamber after the CMP process, comprising: a wafer thickness measuring device, a lifting device, a cleaning tank and a drying gas jet bar;

[0026] The drying gas injection rod is located above the cleaning tank and is used to inject drying gas;

[0027] The wafer thickness measuring device is located above the drying gas injection rod and is used to measure the wafer thickness during the upward process after the wafer cleaning is completed.

[0028] The lifting device is used to lift the cleaned wafer along the wafer surface direction;

[0029] The cleaning tank contains liquid cleaning agent.

[0030] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0031] (1) The existing wafer surface thin film thickness measurement requires a separate step, and the wafer surface thin film thickness measuring device is installed in a separate measuring chamber. The measuring device of this application is based on the Marangoni drying device and is installed above the gas jet rod of the Marangoni drying device. It is not necessary to set up a separate device for measuring the wafer surface thin film thickness, saving valuable equipment space and significantly reducing equipment manufacturing costs.

[0032] (2) In the prior art, the wafer surface thin film thickness measurement is a separate measurement process after cleaning and drying following CMP. The CMP effect measurement of the present invention completely overlaps with the Marangoni drying time, effectively utilizing the Marangoni drying time after CMP cleaning, reducing process steps, compressing process time, and improving the production efficiency of the entire semiconductor production line. The efficiency improvement is extremely significant in processes that require multiple CMP operations.

[0033] (3) The wafer surface thin film thickness measurement of the present invention is based on Marangoni drying. The thickness of the wafer surface thin film after drying is measured online in real time, which effectively prevents secondary contamination of particles that may be caused by the conveying equipment and process in the prior art, avoids wafer scratches, and reduces the number of times the wafer is gripped and placed by the robot, thus reducing the occurrence of wafer breakage due to the mechanical force of the robot gripping.

[0034] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from the description and drawings, which are particularly pointed out. Attached Figure Description

[0035] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0036] Figure 1a A schematic diagram showing the process before the drying of Marangoni begins;

[0037] Figure 1b Schematic diagram of the drying process of Marangoni;

[0038] Figure 1c This is a schematic diagram showing the process after the Marangoni drying is complete.

[0039] Figure 2a A schematic diagram showing the CMP effect measurement based on Marangoni drying before it begins;

[0040] Figure 2b A schematic diagram illustrating the CMP effect measurement based on Marangoni drying;

[0041] Figure 2c This is a schematic diagram showing the CMP effect measurement after Marangoni drying. Detailed Implementation

[0042] In a single CMP process, measuring the CMP effect requires a separate measurement process, resulting in wasted steps. In a multi-CMP process, multiple CMP operations are required, with each wafer undergoing cleaning and then being measured in a measurement chamber, leading to numerous repetitive steps and low production efficiency. Furthermore, the transfer of wafers to the measurement chamber may introduce solid particles that settle on the wafer surface, compromising measurement accuracy and causing surface damage. The transfer of wafers from the cleaning unit to the measurement chamber and onto the thickness gauge platform, and then from the thickness gauge platform to the next process step, requires multiple gripping operations by a robotic arm. These gripping operations apply physical force, increasing the risk of wafer breakage with each subsequent gripping operation. Additionally, the entire process necessitates a separate measurement chamber for determining the wafer surface film thickness, resulting in significant space requirements and increased manufacturing costs.

[0043] Based on the above issues, and considering the cleaning process after CMP, the wafer is first placed in a cleaning solution tank, where solid particles on the surface are washed away using liquid cleaning agents such as deionized water. Then, the cleaning solution is completely removed from the wafer surface via Marangoni drying. The Marangoni drying process is as follows: Figure 1a , Figure 1b and Figure 1c As shown, Marangoni drying involves lifting the wafer from the cleaning agent tank using a lifting device. At the solid-liquid interface between the wafer and the cleaning agent, a mixture of heated isopropanol (IPA) vapor and nitrogen is sprayed through a spray rod, forming a gas-solid-liquid three-phase interface. Since isopropanol is soluble in water, isopropanol and water form mixed droplets. Under the action of the gas, the surface tension changes, and the mixed droplets are drawn away by deionized water, thus drying the wafer. Because the driving force of this process is the change in liquid surface tension at the gas-solid-liquid three-phase interface, the process is relatively slow. To accommodate this process, the lifting device lifts the wafer at a slow speed, resulting in a long drying time. This invention utilizes the Marangoni drying time to measure the CMP effect, providing a CMP effect measurement device and method based on Marangoni drying.

[0044] The wafer thickness measurement device after CMP process provided by the present invention includes:

[0045] Wafer thickness measurement equipment;

[0046] The wafer thickness measuring device is installed inside the cleaning chamber and above the dry gas injection port above the cleaning agent pool. It is used to measure the wafer thickness during the rising process after the wafer cleaning is completed.

[0047] Specifically, the wafer thickness measurement equipment includes an optical transmitter and an optical receiver; the optical transmitter and the optical receiver are located in the cleaning chamber, both above the dry gas injection port; the optical transmitter is used to emit detection light; the optical receiver is used to receive the detection light after it has been reflected and refracted by the wafer surface.

[0048] The CMP effect measurement device of this invention measures the CMP effect by measuring the film thickness on the surface of a wafer after cleaning and drying following CMP. This differs significantly from existing methods for measuring thin films on wafer surfaces.

[0049] (1) From the perspective of the measuring device, the measuring device of the present invention is integrated with the Marangoni drying device, making full use of the idle space of the Marangoni drying device, turning two devices into one device, greatly reducing the space occupied by the equipment and greatly reducing the equipment cost.

[0050] (2) In terms of measurement method, current methods for measuring the thickness of thin films on wafer surfaces involve placing the wafer horizontally on the measurement platform of the measuring equipment and fixing the wafer with a fixing device. Unlike the current measurement method, the present invention directly measures the thickness of the wafer during the Marangoni drying process. Since the Marangoni drying process uses a lifting device to vertically lift the wafer out of the cleaning agent tank, the present invention adopts a vertical measurement method.

[0051] (3) From the perspective of the measurement process, the existing technology places the wafer horizontally on the measurement platform of the measuring equipment and measures the thickness of the thin film on the wafer surface by rotating the wafer. The present invention measures the thickness of the thin film on the wafer surface based on Marangoni drying, and the wafer moves in a vertical linear motion.

[0052] (4) From the perspective of process flow, the Marangoni drying after the existing CMP process is completed in the cleaning chamber, which is a subsequent cleaning process of CMP, while the measurement of the wafer surface film thickness is completed in the measurement chamber, which is a separate measurement process; In this invention, the wafer surface film thickness is measured during the Marangoni drying to complete the subsequent cleaning and measurement of CMP, which is completed in one step in the cleaning equipment chamber, and the cleaning, drying and measurement after the CMP process are integrated into one process.

[0053] Considering the extremely wide range and classification of light based on wavelength, and based on the Marangoni drying equipment and process flow, a laser emitter was specifically chosen as the optical transmitter, and a laser receiver as the optical receiver. This is because laser equipment is relatively small in size, has good laser directionality, and provides excellent measurement results.

[0054] Based on the foregoing analysis, the present invention measures the CMP effect by simultaneously measuring the film thickness on the wafer surface during the Marangoni drying process. Therefore, the optical transmitter, optical receiver, and gas jet rod start and stop working simultaneously, thereby achieving synchronous measurement and drying.

[0055] Considering the size of the equipment and the measurement requirements of the optical measurement equipment, the optical transmitter and receiver are positioned 1-4 cm away from the wafer lifting motion plane, which is the wafer plane during the lifting process. If the optical transmitter and receiver are too close to the wafer lifting motion plane, the laser path may be too short, resulting in a small displacement of the detection light emitted by the optical transmitter after reflection and refraction on the wafer surface film, making it unrecognizable and measurable by the optical receiver. Furthermore, being too close makes the optical transmitter and receiver prone to collisions with the wafer lifting device, hindering equipment replacement and maintenance. Therefore, the minimum distance between the optical transmitter and receiver and the wafer lifting motion plane is 1 cm. If the optical transmitter and receiver are too far from the wafer lifting motion plane, the laser path may be too long, resulting in a large displacement of the detection light emitted by the optical transmitter after reflection and refraction on the wafer surface film, exceeding the detection range of the optical receiver and making it unmeasurable. Therefore, the distance between the optical transmitter and receiver and the wafer lifting motion plane is determined to be 1-4 cm.

[0056] The horizontal positions of the optical emitter and receiver are the same as the horizontal position of the lifting device when the wafer is raised to its highest position. Since the CMP effect measurement device is based on Marangoni drying, the lifting device's displacement, start point, and end point are fixed during Marangoni drying. The horizontal positions of the optical emitter and receiver are determined by the start and end times of the CMP effect measurement. To achieve effective measurement of the CMP effect by measuring the thin film thickness at various locations on the entire wafer surface, the CMP effect measurement device must measure the thin film thickness at all locations on the wafer surface. The measurement start time is the same as the drying start time, and the measurement end time is the same as the drying end time. Therefore, the horizontal position of the optical emitter and receiver is above the gas jet bar, the same as the horizontal position of the lifting device when the wafer is raised to its highest position.

[0057] Specifically, when the optical transmitter is a linear optical transmitter and the optical receiver is a linear optical receiver, the CMP effect measurement device can not only measure the thickness of the thin film at various locations on the entire wafer to obtain an accurate measurement of the CMP effect, but also minimize the equipment manufacturing cost of the optical transmitter and optical receiver and reduce the space occupied by the equipment.

[0058] To ensure that the CMP effect measurement device can measure the thickness of the thin film at various locations on the entire wafer, the linear optical emitter and linear optical receiver are placed horizontally, and the length d1 of the linear optical emitter is not less than the wafer diameter d. To ensure that the detection light emitted by the optical emitter has a large displacement after reflection and refraction of the thin film on the wafer surface, and is still within the detection range of the optical receiver so that it can be received and measured, the length d2 of the linear optical emitter is not less than 1.1 times d1.

[0059] After CMP (Chemical Motion Processing), the polishing slurry particles on the wafer surface are cleaned using chemical cleaning agents such as deionized water and isopropanol. After cleaning, the wafer is lifted from the cleaning agent using a lifting device, and isopropanol vapor is used to dry the wafer surface using the Marangoni principle. Because the lifting device is in contact with the wafer edge, isopropanol tends to accumulate at the contact area due to liquid surface tension. This accumulated isopropanol may contain particles from the cleaning agent. Therefore, cleaning with isopropanol not only causes isopropanol accumulation but also results in particle residue, adversely affecting subsequent processes. To avoid this problem, in one possible solution, the laser emitted by the optical emitter of this invention can also be used to dry the residual liquid accumulated at the contact area between the lifting device and the wafer edge.

[0060] The present invention provides a method for measuring the CMP effect based on Marangoni drying, such as... Figure 2a , Figure 2b and Figure 2c As shown, using the aforementioned CMP effect measurement device based on Marangoni drying, the lifting device starts by lifting the wafer from the cleaning agent pool, and the Marangoni drying gas injection rod starts to spray gas. When the highest point of the wafer is aligned with the drying gas injection nozzle, the optical transmitter and optical receiver start to work. As the lifting device slowly and gradually lifts the wafer to the highest point, the optical receiver detects the detection light emitted by the optical transmitter and reflected and refracted by the wafer surface to obtain the thickness of the thin film at various positions on the entire wafer surface. The CMP effect is measured by the thickness of the thin film at various positions on the entire wafer surface.

[0061] In one possible approach, the gas injected by the gas jet is a mixture of high-temperature isopropanol vapor and nitrogen, with a volume ratio of isopropanol to nitrogen of 1:4 to 4:1, meaning the volume percentage of isopropanol is 20%-80%. Considering that the isopropanol content in the gas directly affects the Marangoni drying rate, and that CMP effect measurement starts and ends simultaneously with the Marangoni drying process, the ratio of isopropanol to the inert nitrogen gas directly affects the speed and duration of the entire drying and CMP effect measurement. If the isopropanol content is below 20%, the Marangoni drying rate is slow, resulting in a slow overall drying and CMP effect measurement process and low production efficiency. Conversely, if the isopropanol content is too high and the nitrogen content is too low, the Marangoni effect diminishes, and the drying rate actually slows down. Therefore, the gas injected by the gas jet is a mixture of high-temperature isopropanol vapor and nitrogen, with a volume ratio of isopropanol to nitrogen of 1:4 to 4:1.

[0062] The following detailed description of preferred embodiments of the present invention illustrates the principles of the invention and is not intended to limit the scope of the invention.

[0063] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the term "connected" should be interpreted broadly. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For those skilled in the art,

[0064] Throughout the text, the terms “top,” “bottom,” “above,” “below,” and “on top” refer to the relative positions of components of the device, such as the relative positions of the top and bottom substrates within the device. It is understood that the device is multifunctional and independent of its spatial orientation.

[0065] The working surface of this invention can typically be a plane or a curved surface, and can be inclined or horizontal. For ease of explanation, the embodiments of this invention are placed on a horizontal surface and used on a horizontal surface, thereby defining "height" and "vertical".

[0066] Example 1

[0067] One specific embodiment of the present invention discloses a wafer thickness measurement device based on Marangoni drying after the CMP process, which is operable on wafers with a maximum diameter of 200 mm.

[0068] The wafer thickness measurement device after the CMP process includes a wafer thickness measuring device. The wafer thickness measuring device is installed in the cleaning chamber and is located above the dry gas injection port above the cleaning agent pool. It is used to measure the wafer thickness during the rising process after the wafer cleaning is completed. The wafer thickness measuring device includes a laser emitter and a laser receiver.

[0069] A laser emitter emits detection light to measure the thickness of the thin film on the wafer surface after CMP.

[0070] The laser receiver receives the detection light after it has been reflected and refracted by the wafer surface.

[0071] The gas injection rod injects a mixture of high-temperature isopropanol vapor and nitrogen, with a volume ratio of isopropanol to nitrogen of 2:1.

[0072] The laser emitter is a linear laser emitter, and the laser receiver is a linear laser receiver.

[0073] The distance between the laser emitter and the laser receiver and the moving plane of the wafer lifting is 2 cm.

[0074] The laser emitter, laser receiver, and gas jet rod start and stop working simultaneously.

[0075] The linear optical transmitter and the linear optical receiver are placed horizontally. The length of the linear optical transmitter is 200mm and the length of the linear optical receiver is 220mm.

[0076] The laser emitted by the laser emitter can also dry the residual isopropanol that accumulates at the contact point between the lifting device and the edge of the wafer.

[0077] Example 2

[0078] One specific embodiment of the present invention discloses a method for measuring wafer thickness after a CMP process.

[0079] The wafer thickness measurement device used in this embodiment is based on the CMP process and can operate on wafers with a maximum diameter of 180mm. The device includes a wafer thickness measurement apparatus; the wafer thickness measurement apparatus is located inside the cleaning chamber and above the dry gas jet nozzle above the cleaning agent tank, and is used to measure the wafer thickness during the rising process after the wafer cleaning is completed. It includes a laser emitter and a laser receiver.

[0080] The gas injection rod injects a mixture of high-temperature isopropanol vapor and nitrogen, with a volume ratio of isopropanol to nitrogen of 1:2.

[0081] The laser emitter emits detection light to measure the thickness of the thin film on the wafer surface after CMP; the laser receiver receives the detection light after reflection and refraction by the wafer surface.

[0082] The laser emitter is a linear laser emitter, and the laser receiver is a linear laser receiver.

[0083] The distance between the laser emitter and the laser receiver and the motion plane for wafer lifting is 1.5 cm.

[0084] The linear optical transmitter and the linear optical receiver are placed horizontally. The length of the linear optical transmitter is 190mm and the length of the linear optical receiver is 210mm.

[0085] During implementation, the lifting device begins to lift the wafer from the cleaning agent pool, and the Marangoni drying gas injection bar begins to spray gas. When the highest point of the wafer is aligned with the drying gas injection nozzle, the optical transmitter and optical receiver begin to work. As the lifting device slowly and gradually lifts the wafer to its highest point, the optical receiver detects the thickness of the thin film on the wafer surface by detecting the detection light emitted by the optical transmitter and reflected and refracted by the wafer surface. The thickness of the thin film on the wafer surface is used to obtain the CMP effect.

[0086] Example 3

[0087] This embodiment provides a wafer cleaning chamber after a CMP process, including: a laser emitter, a laser receiver, a lifting device, a cleaning tank, an isopropanol jetting rod, a laser heater, and a temperature detector. This embodiment is suitable for wafers with a maximum diameter of 180 mm.

[0088] The laser emitter is a linear laser emitter, and the laser receiver is a linear laser receiver.

[0089] The distance between the laser emitter and the laser receiver and the motion plane for wafer lifting is 1.5 cm.

[0090] The linear optical transmitter and the linear optical receiver are placed horizontally. The length of the linear optical transmitter is 190mm and the length of the linear optical receiver is 210mm.

[0091] The isopropanol spray bar is located above the cleaning tank and is used to spray isopropanol to dry the wafer.

[0092] The lifting device is used to lift the cleaned wafer along the wafer surface.

[0093] The cleaning tank contains deionized water.

[0094] The laser heater is located above the isopropanol jet bar, level with the highest position of the wafer lifting device.

[0095] Temperature detectors are used to monitor the temperature of the area where the wafer contacts the lifting device and the lower edge of the wafer in real time.

[0096] The heating element of the laser heater is rectangular in shape.

[0097] The laser heater is 2 cm away from the wafer plane.

[0098] The heating temperature of the laser heater is 30-50℃, which is achieved by detecting and adjusting the laser power of the laser heater through a temperature detector.

[0099] The width of the laser heater heating body is 108mm, and the height of the heating body of the heating device is 27mm.

[0100] After CMP, the polishing slurry particles on the wafer surface are cleaned with deionized water. After cleaning, the wafer is lifted from the cleaning agent using a lifting device. As the wafer is lifted to its highest position, the isopropyl alcohol jetting rod begins to spray gas. When the highest point of the wafer is aligned with the dry gas nozzle, the laser emitter and laser receiver start working. As the lifting device slowly and gradually lifts the wafer to its highest point, the laser receiver detects the thickness of the thin film at various locations on the entire wafer surface by detecting the detection light emitted by the optical emitter and reflected and refracted by the wafer surface.

[0101] After the isopropanol spraying rod finishes spraying, the laser heater is activated. The laser heater irradiates the area where the wafer contacts the lifting device and the lower edge of the wafer after isopropanol spraying and drying, thus achieving complete drying of the entire wafer.

[0102] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A wafer thickness measuring device in a post-CMP cleaning chamber, characterized in that, Including wafer thickness measurement equipment; The wafer thickness measuring device is installed inside the cleaning chamber and above the drying gas injection port above the cleaning agent pool; it is installed above the gas injection rod of the Marangoni drying device; after the wafer cleaning is completed, it rises in a direction parallel to the wafer surface under the action of the lifting mechanism. The wafer thickness measuring device is used to measure the wafer thickness during the rising process after the wafer cleaning is completed. When the highest point of the wafer is flush with the dry gas injection port, the wafer thickness measuring device starts to work, realizing the measurement of the thin film at various positions on the surface of the entire rising wafer. The wafer thickness measurement device includes a linear optical emitter and a linear optical receiver. The optical emitter is a laser emitter, and the optical receiver is a laser receiver. The linear optical emitter and the linear optical receiver are placed horizontally. The detection width d1 of the detection light of the linear optical emitter is not less than the wafer diameter d, and the detection width d2 of the detection light of the linear optical receiver is not less than 1.1 times d1. The linear optical emitter is used to emit detection light, and the linear optical receiver is used to receive the detection light after reflection and refraction by the wafer surface. The linear optical emitter, the linear optical receiver and the dry gas injection port start working simultaneously. The linear optical transmitter and the linear optical receiver are 1-4 cm away from the wafer surface, and their horizontal positions are the same as the horizontal positions of the lifting device when the wafer is lifted to its highest position. The laser emitted by the linear optical emitter can also be used to dry residual liquid that accumulates at the contact point between the lifting device and the wafer edge.

2. The wafer thickness measurement device after CMP process according to claim 1, characterized in that, Both the linear optical transmitter and the linear optical receiver are located inside the cleaning chamber and above the dry gas injection port above the cleaning agent pool.

3. The wafer thickness measurement device after CMP process according to claim 2, characterized in that, The linear optical transmitter and the linear optical receiver are installed at a position no higher than the highest position of the rising wafer.

4. A method for measuring wafer thickness after a CMP process using the apparatus described in any one of claims 1-3, characterized in that, include: After the CMP process, the wafer enters the cleaning chamber; After the wafer is cleaned in the cleaning agent pool in the cleaning chamber, it is lifted by the lifting device. As the wafer begins to rise, the drying gas nozzle begins to inject Marangoni drying gas; When the highest point of the wafer is aligned with the dry gas nozzle, the wafer thickness measurement device above the dry gas nozzle starts working to detect the thickness of the rising wafer in real time.

5. The wafer thickness measurement method after CMP process according to claim 4, characterized in that, The drying gas nozzle is located on the spray rod, and the sprayed gas is a mixture of high-temperature vapor of isopropanol and nitrogen, with a volume ratio of isopropanol to nitrogen of 1:4 to 4:

1.

6. A wafer cleaning chamber after a CMP process, characterized in that, include: The wafer thickness measuring device, lifting device, cleaning tank, and drying gas injection bar as described in any one of claims 1-3; The drying gas injection rod is located above the cleaning tank and is used to inject drying gas; The wafer thickness measuring device is located above the drying gas injection rod and is used to measure the wafer thickness during the upward process after the wafer cleaning is completed. The lifting device is used to lift the cleaned wafer along the wafer surface direction; The cleaning tank contains liquid cleaning agent.

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